Pavela,⁎ , Christian Thielb, Stefanie Degreifc, Darina Blagoevaa, Matthias Buchertc, Energy, Transport and Climate Directorate, Joint Research Centre, European Commission, Westerduinweg
Trang 1UNCORRECTED PR
OOF
3Q1 Claudiu C Pavela,⁎ , Christian Thielb, Stefanie Degreifc, Darina Blagoevaa, Matthias Buchertc,
Energy, Transport and Climate Directorate, Joint Research Centre, European Commission, Westerduinweg 3, 1755 LE Petten, The Netherlands
Energy, Transport and Climate Directorate, Joint Research Centre, European Commission, Enrico Fermi 2749, I - 21027 Ispra, (VA), Italy
Oeko-Institut e.V., Rheinstrasse 95, 64295 Darmstadt, Germany
8
a b s t r a c t
9 a r t i c l e i n f o
10 Article history:
11 Received 7 September 2016
12 Received in revised form 6 December 2016
13 Accepted 19 January 2017
14 Available online xxxx
15
20 The development of new high-efficiency magnets and/or electric traction motors using a limited amount of
21 critical rare earths or none at all is crucial for the large-scale deployment of electric vehicles (EVs) and related
22 applications, such as hybrid electric vehicles (HEVs) and e-bikes For these applications, we estimated the
23 short-term demand for high-performing NdFeB magnets and their constituent rare earths: neodymium,
praseo-24 dymium and dysprosium In 2020, EV, HEV and e-bike applications combined could require double the amount
25 used in 2015 To meet the global deployment target of 7.2 million EVs sales in 2020 proposed by the International
26 Energy Agency, the demand for NdFeB in the EV sector might increase by up to 14 times in only 5 years (2015–
27 2020) Due to concerns about the security of supply of rare earths some manufacturers have decided to develop
28 and adopt alternative solutions By assessing up-to-date available component substitutes, we show that the
29 permanent magnet synchronous-traction motor (PSM) remains the technology of choice, especially for hybrid
30 vehicles (HEV and PHEV) Better material efficiency and a larger adoption of motors free of rare earths have
31 the potential to reduce the pressure on rare earths supply for use in electric road transport applications However
32 even if such substitution measures are successfully implemented, the demand growth for rare earths in the EV
33 sector is expected to increase significantly by 2020 and beyond
34
© 2017 Joint Research Centre, European Commission Published by Elsevier B.V This is an open access article under
36 Keywords:
37 Critical materials
38 Rare earths
39 Electric vehicles
40 Substitution
41 Permanent magnet
42
44
45
46 Contents
48 1 Introduction 0
49 2 Sources and approach 0
50 3 Estimation of permanent magnets demand in traction motors used in electric road transport applications 0
51 3.1 Applications of permanent magnets in electric traction motors 0
52 3.2 Estimation of NdFeB magnet demand in electric vehicle types BEV and PHEV 0
53 3.3 Market momentum of hybrid vehicles and estimation of NdFeB magnet demand in HEV applications 0
54 3.4 Estimation of NdFeB magnet demand in e-bikes 0
55 3.5 Supply issues for rare earths and their demand for electric road transport applications (H&EVs and e-bikes) 0
56 4 Substitution opportunities of rare earths in electric traction motors 0
57 4.1 Rare earths substitution in NdFeB magnets and improved material efficiency 0
58 4.2 Reducing the amount of NdFeB magnet in electric traction motor: dematerialisation 0
59 4.3 Component substitution for PSM traction motors in EVs and HEVs 0
60 5 Impact of substitution on short-term demand for critical rare earths– Nd, Pr and Dy – in H&EV and e-bike applications 0
61 6 Conclusions 0
62 Acknowledgements 0
63 References 0
64
Sustainable Materials and Technologies xxx (2017) xxx–xxx
⁎ Corresponding author.
E-mail address: claudiu.pavel@ec.europa.eu (C.C Pavel).
SUSMAT-00036; No of Pages 11
http://dx.doi.org/10.1016/j.susmat.2017.01.003
2214-9937/© 2017 Joint Research Centre, European Commission Published by Elsevier B.V This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/ 4.0/ ).
Contents lists available atScienceDirect Sustainable Materials and Technologies
j o u r n a l h o m e p a g e :w w w e l s e v i e r c o m / l o c a t e / s u s m a t
Please cite this article as: C.C Pavel, et al., Role of substitution in mitigating the supply pressure of rare earths in electric road transport applications, (2017),http://dx.doi.org/10.1016/j.susmat.2017.01.003
Trang 2UNCORRECTED PR
OOF
65 1 Introduction
66 Countries gathered at the 2015 Paris Climate Conference (COP21)
67 agreed to increase their efforts to limit climate change Transport is a
68 growing sector that contributes almost one-quarter of current global
69 energy-related GHG emissions More than half of this is related to
70 road passenger transport[1,2] For example, in Europe, transport
71 accounts for more than 30% offinal energy consumption and the
72 European Commission is already taking actions to decarbonise the
73 transport sector[3] Limiting global temperature increases to below
74 2 °C requires sustainable transportation solutions Electromobility for
75 various transport modes coupled with a low-carbon power system is
76 seen as a promising sustainable solution Electrified road transport is
77 not a new concept, but it is only recently that electric vehicles (EVs)
78 have gained relevant mass-market sales through third-generation
79 technology Several factors push up the electromobility trend, such as
80 the increasing volatility of oil prices, air quality concerns, climate change
81 agreements, more stringent emission standards and market
momen-82 tum for EVs At the end of 2015, the global EV stock accounted for
83 over 1.26 million units and global EV sales in 2015 amounted to over
84 550,000 cars[4] Although the number of electric vehicles on the road
85 is still very low when compared to the total number of passenger cars
86 worldwide (0.1%), the shift towards electrified powertrains is becoming
87 more apparent For instance, in 2015 the share of passenger EVs
88 exceeded 1% of new market sales in Norway, the Netherlands,
89 Sweden, Denmark, France, China and the UK[4]
90 Several countries have set up ambitious sales and/or stock targets
91 regarding vehicle electrification as guidance for creating national
92 roadmaps and for gathering support from policymakers Among various
93 uptake scenarios, the International Energy Agency (IEA) and the Electric
94 Vehicles Initiative (EVI), a multi-government policy forum composed
95 today of 16 members, presented an aggregated global deployment
96 target of 7.2 million in annual sales of EVs and 24 million in EVs stock
97 by 2020[5] This is an important milestone in meeting the global
98 deployment target of 100 million EVs by 2030 as announced at COP21
99 in the Paris declaration on electromobility and climate change and call
100 for action[4] An even more ambitious target (140 million EVs by
101 2030) is presented by IEA under the 2 °C scenario[4] For instance in
102 Europe the combined targets aim to reach up to 8–9 million EVs
103 on the road by 2020, but specific targets and timelines are subject to
104 negotiation with the EU's member states[6]
105 It is important to consider here the impact of availability of material
106 resources and their secure supply on the future deployment pathway of
107 EVs in view of the overall concerns about the supply of certain materials
108 in the global transition to a sustainable energy future[7–10] In previous
109 studies conducted by the European Commission's Joint Research Centre
110 (JRC) we showed that several low-carbon energy technologies could be
111 at risk because of potential bottlenecks in the supply chains of certain
112 metals[11–13] Among these technologies, electric vehicles are of
113 particular concern due to the dependence on critical rare earths used
114 in NdFeB permanent magnets (PM), which are essential for producing
115 light, compact and high efficiency traction motors Such magnets
116 contain neodymium (Nd), praseodymium (Pr) and dysprosium (Dy)
117 rare earths in their composition Dysprosium is used as an additive to
118 improve the magnet coercivity at high temperatures[14]
119 In recent years, traditional asynchronous motors have been
continu-120 ously replaced by more efficient devices containing permanent
121 magnets, e.g high efficient PM synchronous-traction motors (PSM) in
122 EVs, HEVs and e-bikes[15] Due to the high energy density of NdFeB,
123 this magnet is also increasingly used in high-tech applications and
124 energy-related devices such as generators in wind turbines[16,17]
125 Consequently, it is expected that the global demand for Nd, Pr and
126 Dy elements will increase in the coming years as the market in these
127 sectors will most likely increase[16,18–20]
128 A series of events, such as imposing export restrictions on rare earth
129 elements (REEs) by the near-monopolist China, caused the supply crisis
130 from 2010 to 2011 that drove up prices by between 4 and 9 times in less
131 than a year[21–24] As a result, the costs of products containing rare
132 earths increased Although prices for rare earths have declined since
133
2013, concerns regarding the supply of rare earths continue among
134 industry and governments as another supply crisis remains a distinct
135 possibility[16,18] These supply concerns are also due to the current
136 reorganisation of rare earth market as well as introduction by the
137 Chinese government of various measures to limit REE production,
138 driven by environmental, social and resources preservation aspects
139 Based on specific risk assessments, rare earths are in general
evalu-140 ated as‘critical materials’[25–30] Different mitigation strategies such
141
as the development of new mines and recycling are being considered,
142 but both are seen as unrealistic to be implemented in the short-term
143 From one side many barriers prevent a fast and sustainable primary
144 production and on the other side large volumes of secondary rare
earth-145 based products are not expected to enter soon into the recycling circuit
146 [24,31,32] In the midst of this is the substitution A complete and direct
147 (one-by-one) replacement of all critical materials by other more readily
148 available or less critical without decreasing product performance, raise
149 the price or both, is very limited[33] However, the substitution of
150 rare earths and other critical materials appears to be a feasible solution,
151 especially in cases where the substitution takes place at the product,
152 component or technology level rather than the element level[34–36]
153 According to Smith and Eggert[36], material substitution has
‘multifac-154 eted’ dimensions and the authors identify five types of substitution in
155 the case of NdFeB magnet: element-for element,
technology-for-156 element, grade-for-grade, magnet-for magnet and system-for-system
157 substitution The literature seems to agree on the fact that substitution
158 represents an essential component of the strategy towards a sustainable
159 use of scarce resources or environmentally problematic materials
160 [37–40]
161 Comprehensive information about the substitution of rare earths in
162 permanent magnets and the impact of this approach on reducing
163 reliance on rare earths in relation to the widespread adoption of electric
164 vehicles is limited in the literature The state-of-the-art of some rare
165 earths-free propulsion motors was addressed in several reviews
166 [15,41,42] Here we intend to complement the literature by assessing
167 the current technological status of these components and offer an
out-168 look on further developments We are focusing on the most promising
169 electric propulsion motor concepts that could be applicable at a large
170 scale within a short period in electric road transport applications
171 (i.e electric vehicles, HEVs and e-bikes)
172
In this paper wefirst estimate the demand for permanent magnets
173 for reaching the global deployment targets for electric vehicles in
174
2020 and describe its link to material resources availability The
compe-175 tition for PM-based traction motors from other applications, in
particu-176 lar HEVs and e-bikes, is also evaluated Then we analyse in-depth the
177 possible substitutes for rare earths-based traction motors and assess
178 their ability to enter into serial production in the short-term (2020)
179 Finally, we evaluate the impact of substitution on reducing the demand
180 for rare earths in electric traction motors under different scenarios
181
2 Sources and approach
182 The research was carried out during 2015–2016 based on
informa-183 tion collected from a wide variety of sources, including academic
184 articles, relevant documents and reports on critical raw materials,
185 industry publications, etc Although an exhaustive survey on the most
186 recent industrial developments is difficult to carry out because of the
187 high level of confidentiality in automotive industries research, this
188 paper integrates the best available information with additional
informa-189 tion gathered from interviews with material scientists, technical experts
190 from industry and academics Over ten interviews have been conducted
191 with European automakers (e.g Daimler, BMW, etc.) and research
pro-192 ject consortium (e.g MotorBrain, CRM_Innonet, etc.) inquiring about
193 their concerns on rare earths supply and feasibility of substitution of
Trang 3UNCORRECTED PR
OOF
194 permanent magnet or rare earths in electric traction motors In most of
195 the cases the experts asked to remain anonymous
196 The demand for rare earths in these applications was estimated
197 using the average amount of permanent magnets in different types of
198 electric powertrains and based on the elemental composition of
199 NdFeB magnets The deployment targets for EVs are those presented
200 by the International Energy Agency (IEA) Other scenarios were used
201 as complementary information and are referenced throughout the
202 paper Our demand projections for permanent magnets and rare earths
203 represent a baseline necessary to carry out a more in-depth substitution
204 analysis
205 From our analysis and interviews with experts it is clear that magnet
206 producers and automotive industries have looked at different types of
207 substitution, some of them being more prevalent than others Four
208 main approaches to reduce the demand for rare earths are evaluated in
209 this paper: improving material usage through a better material efficiency,
210 dematerialization (using less NdFeB magnet), direct substitution of rare
211 earths in magnet (element-for-element substitution) and adoption of
212 rare earth-free traction motors (defined as component substitution)
213 The impact of substitution on decreasing the demand for rare earths
214 in three electric transport sectors– EVs, HEVs and e-bikes – was
calcu-215 lated based on assumed scenarios While the potential of improving
216 material efficiency is estimated according with industry experts,
217 adoption rate of rare earth-free motors and dematerialisation are
218 more arbitrarily chosen in order to highlight in impact of component
219 substitution on decreasing the future demand for rare earths
220 3 Estimation of permanent magnets demand in traction motors
221 used in electric road transport applications
222 3.1 Applications of permanent magnets in electric traction motors
223 Today, the NdFeB alloy is a high power magnet with the largest sales
224 share in the permanent magnets market[43] Based on their high energy
225 density NdFeB magnets are widely used in the automotive industry
226 either for electric traction motors or for non-traction electric
compo-227 nents such as audio speakers, transmission, electric power steering,
228 electronic sensors, etc.[17] Since the magnet content is estimated as
229 negligible in non-traction components[44], in this paper we take into
230 account only electric traction motors
231 There is a large diversity of electric propulsion systems available
232 today In general electric vehicles refer to the passenger cars that have
233 an electric motor as the primary source of propulsion using electrical
234 energy from the grid stored in rechargeable batteries[6,45] The
235 EV group comprises: battery electric vehicles (BEVs), fuel cell electric
236 vehicles (FCEVs), range-extended electric vehicles (REEVs) and
plug-237 in electric vehicles (PHEVs) Hybrid electric vehicles (HEVs) are not
238 part of EV category since the electric motor represents a secondary
239 propulsion source in combination with an internal combustion engine
240 (ICE) In this paper we will refer to the electric vehicle types BEV and
241 PHEV as well as HEV as these three classes are the most common
242 variants and they may make use of NdFeB magnet[46]
243 Currently most HEVs and EVs (abbreviated as H&EV) use
synchro-244 nous motors with NdFeB permanent magnets It is estimated that
245 by 2025 between 90 and 100% of H&EVs sales will be based on this
tech-246 nology[47] Overall several reasons explain the common use of rare
247 earth-based PSM in H&EVs[41,48,49]:
248 • The very strong magnetic field of integrated NdFeB magnets allows a
249 light and compact motor design;
250 • PSMs have a high efficiency since no external power system is needed
251 to induce a magneticfield in the rotor The magnetic field is provided
252 by permanent magnet whereas other motor concepts require
electric-253 ity to generate this electricfield;
254 • PSMs supply high torque and can be more easily controlled
255 E-bikes represent an additional application for NdFeB-based PSM
257 because of their ability to offer low weight and compact size Significant
258 growth rates for e-bikes were registered in the recent years, with almost
259 all production and demand concentrated in China[50]
260 3.2 Estimation of NdFeB magnet demand in electric vehicle types BEV and
261 PHEV
262 Based on the current technology, a PSM for an electric vehicle needs
263 between 1 and 2 kg NdFeB depending on motor power, car size, model,
264 etc.[44,47] If all of the EVs (BEV and PHEV) sold worldwide in 2015
265 (about 550,000 passenger cars) had been produced with NdFeB
266 magnets, then up to 1100 tonnes of NdFeB would have been required
267 This amount represents just over 1% of the global production of NdFeB
268 magnets, which was estimated to range between 79,000 tonnes[51]
269 and about 80,000 tonnes[52]in 2015 To meet the global deployment
270 target of 7.2 million EV sales in 2020[5], the number of EVs produced
271 would need to grow progressively on average by approximately 67%
272 compound annual growth rate (CAGR) from 2015 until 2020 Assuming
273 that all 7.2 million EVs will use PSM motors, these would require
274 between 7200 and 14,400 tonnes of NdFeB magnets in 2020 This
trans-275 lates to a significant increase in the annual demand for NdFeB magnets
276
in EVs by up to 14 times in only 5 years (Fig 1)
277 Today China dominates the production of NdFeB magnets by 85–
278 90%, the rest being produced in Japan (10%) and in other countries
279 from Europe, the USA, etc.[52] Their manufacture appears to continue
280
to move to China where access to REEs remains cheapest and most
281 secure[18]
282 3.3 Market momentum of hybrid vehicles and estimation of NdFeB magnet
283 demand in HEV applications
284 The number of new H&EVs models significantly increased from 12 to
285
60 in the period 2010–2014 (Fig 2) In 2014 hybrid types HEV and PHEV
286 constituted 65% of the new electric models launched The high market
287 momentum of HEV, and more recently PHEV, reflect consumer
prefer-288 ence for no compromises in range compared to BEV, combined with
289 lower fuel consumption compared to conventional ICE vehicles
290 The evolution of H&EV penetration rates of these models is very
291 sensitive to several factors, such as the price of oil, the cost and efficiency
292
of the battery-pack, regulations, government support, infrastructure,
293 customer preferences, etc An additional factor that could potentially
294
influence the future adoption of electric and hybrid vehicles derives
295 from the availability of rare earths and downstream products (e.g
296 NdFeB magnet) It is estimated that all HEV and PHEV commercialised
Fig 1 Evolution of global annual sales of electric vehicles (BEV and PHEV) since 2010 [4]
and 2020 deployment target [5] Estimation of NdFeB demand is based on the assumption that all EVs use NdFeB-PSM technology The error bar represents the standard error calculated based on the minimum and maximum amount of NdFeB magnet used in a PSM.
3 C.C Pavel et al / Sustainable Materials and Technologies xxx (2017) xxx–xxx
Please cite this article as: C.C Pavel, et al., Role of substitution in mitigating the supply pressure of rare earths in electric road transport applications, (2017),http://dx.doi.org/10.1016/j.susmat.2017.01.003
Trang 4UNCORRECTED PR
OOF
297 today use PSM[41,47], thus competing with BEV and other technologies
298 for the same materials The compact size and high performance of PSM
299 makes it the favoured technology for hybrid cars because manufacturers
300 have to cope with space restrictions due to the need to integrate
301 two drive trains into the car (the electric engine and the combustion
302 engine)
303 According to Navigant Research, approximately 2.1 million HEVs
304 were sold globally in 2015[53], mostly in Japan, followed by the USA
305 and Europe[54,55] Global annual HEVs sales are expected to increase,
306 reaching 2.8 million in 2020 under a conservative scenario[53]or
307 over 3.5 million in a more optimistic one[52] Further in our analysis
308 we take into account the average of 3.15 million HEVs sales in 2020
309 An HEV propulsion motor needs less PM material than an EV motor,
310 circa 42% of the EV-motor magnet weight[56] This translates to a range
311 of 0.42–0.84 kg magnet per HEV Under this assumption up to
312 1800 tonnes NdFeB have been used to produce 2.1 million HEVs in
313 2015, representing a small fraction (2.3%) of current global production
314 (Fig 3)
315 The market trends indicate that HEV models will still remain the
316 dominant electric powertrain in the near future[57] Based on our
pro-317 jections, the demand for NdFeB in the global HEV market is not expected
318 to see very significant growth levels in the short-term Up to
319 2650 tonnes of NdFeB would be required for the 3.15 million HEV,
320 about 1.5 times more compared to 2015
321 3.4 Estimation of NdFeB magnet demand in e-bikes
322 E-bikes integrate a small electric motor and rechargeable batteries to
323 assist the rider in pedalling In general, they are classified as bicycles
324 given their ability to be pedalled, distinguishing them from electric
325 scooters and motorcycles Most e-bikes use PSMs with an NdFeB
326 magnet, either as hub motors (integrated in the front or rear wheel)
327
or as mid-drive motors (near the bottom bracket) The amount of
328 NdFeB magnet in an e-bike is estimated to range from 60 g to 350 g
329 [58] Since the NdFeB magnet has to cope with temperatures of
330
up to 100 °C, it needs a low share of dysprosium to withstand
331 demagnetisation According to experts, the loading of dysprosium in
332 NdFeB magnet for e-bikes application is around 1% Dy, much lower
333 compared to 4% found by Hoenderdaal et al.[59] for two-wheel
334 vehicles, which include along e-bikes also electric scooters and electric
335 motorcycles[59] This difference might be also somewhat a result of
336 manufacturer efforts to improve efficiency in materials use Later in
337 this analysis we take into account a conservative loading of 1% Dy in
338 NdFeB magnet for e-bikes
339 The global e-bike sales are much higher than current sales of H&EV
340
It is indicated that about 40 million e-bikes were sold globally in 2013,
341 with China being the biggest market, followed by Europe, Japan and
342 the USA (Fig 4)[50]
343 Due to a high saturation of ownership a slower growth was
344 registered in the e-bike sector during the period 2013–2015[50,52]
345 But the global e-bike market is expected to increase further at a CAGR
346
of over 4% until 2019[60] Based on these data, we estimate that around
347
50 million e-bikes will be sold in 2020 On the assumption that the
348 e-bikes sold in 2015 is similar to that in 2013 and all e-bikes have
349 used an NdFeB-based PSM, circa 2400–14,000 tonnes of NdFeB would
350 have been required in 2015 The maximum amount represents more
351 than 17% of current global NdFeB production and is approximatively
352
13 times higher than the quantity requested for EVs in the same year
353
In 2020 the demand for NdFeB in the e-bikes sector is expected to
354 increase up to 17,500 tonnes using current technology
355 When adding the NdFeB amounts used in the three sectors– EVs,
356 HEVs and e-bikes– the total annual demand for NdFeB magnet in
357
2015 could range from about 4000 tonnes in the lower bound case
358 and up to 16,900 tonnes in the upper bound case The upper and
359 lower bound cases indicate the maximum and minimum masses of
360 NdFeB magnet needed in an e-bike motor The maximum amount of
361 NdFeB requested for these three sectors represents about 21% of the
362 current global production
363 More importantly, the NdFeB demand for these electric road
trans-364 port applications could increase very rapidly in the next 5 years, driven
365
by EV deployment targets (Fig 5) To meet the global deployment target
366
of 7.2 million in 2020, the NdFeB demand is estimated to increase by
367 around 1200% between 2015 and 2020 For HEV and e-bikes this
368 increase is much less compared to EV, for instance by 50% and 25%,
369 respectively
Fig 2 Estimation of new electric vehicles and HEVs models released since 2010 [6]
Fig 3 Evolution of global annual HEV sales, 2020 forecast [53–55] and estimation of the
NdFeB demand for HEV The error bar represents the standard error calculated based on
the minimum and maximum amount of NdFeB magnet used in a PSM Fig 4 Estimated e-bikes sales by country in 2013 in million units [50]
Trang 5UNCORRECTED PR
OOF
370 In 2020, about 11,500–34,500 tonnes NdFeB magnet might be
371 requested globally for the electric road transport applications In the
372 upper bound case the NdFeB amount corresponds to a share of over
373 43% of the current global NdFeB supply When taking into account the
374 forecasted production of NdFeB magnet in 2020, such as 118,000 tonnes
375 [52], this share decreases to about 30%, but still a very significant
376 fraction of the supply
377 3.5 Supply issues for rare earths and their demand for electric road
378 transport applications (H&EVs and e-bikes)
379 The global growth rate of NdFeB consumption for high-tech
applica-380 tions (e.g hard disk drives) and other energy-related devices (e.g wind
381 turbines) is likely to increase in the near future[52], thus competing
382 with NdFeB and its constituent rare earths for electric road transport
383 applications These trends highlight that the REE supply issue must
384 remain high on the agenda of security of supply policies despite recent
385 positive developments such as the lifting China's export bans and
386 decreasing rare earth prices Other factors to be considered are that
387 the rare earths market is still small and dominated by Chinese
produc-388 tion and Chinese demand Thus it may become again susceptible to
389 pricefluctuation
390 In 2014 the global annual production of rare earths (in metal form)
391 was estimated to be around 21,000 tonnes Nd, 6300 tonnes Pr and
392 1400 tonnes Dy[61] The NdFeB magnet is the major application for
393 all three rare earths[61]
394 The composition of NdFeB magnet is presented inTable 1
395 For applications with a shorter operating period (e.g in speakers,
396 computer devices, etc.) the NdFeB permanent magnet is ideal However,
397 for applications like electric traction motors, which have longer
398 operating times and generate significant amounts of heat, NdFeB is
399 less suitable due to its reduced coercivity In fact, at temperatures
400 above 80–120 °C, the coercivity of NdFeB declines significantly
401 Both dysprosium and terbium can be used as a dopant to enhance the
402 coercive force of an NdFeB magnet and enable it to perform stably at
403 higher temperatures Currently, dysprosium is the most convenient
404 dopant because of its low price compared to terbium The dysprosium
405 loading in an NdFeB magnet for electric vehicle can vary between 3.7
406 and 8.7% [59,63], and the resulting compound demonstrates an
407 increased coercivity between 100 and 200 °C For practical reasons
how-408 ever the content of dysprosium in NdFeB magnet used in electric vehicle
409 motor is kept high, up to 7.7%[59] According to experts the actual Dy
410 share in NdFeB magnet for an electric traction motor in EV is around
411 7.5%
412 Taking into account the fraction of rare earths in magnet
composi-413 tion (i.e 30% Nd/Pr (Nd:Pr = 4:1) and 7.5% Dy in H&EVs (or 1% Dy in
414 e-bikes)) and NdFeB demand projected in the previous sections, about
415
920–4050 tonnes Nd, 230–1010 tonnes Pr and 130–355 tonnes Dy
416 would have been required to satisfy the HEVs, EVs and e-bikes market
417
in 2015 In terms of demand/production share, the three sectors
com-418 bined accounted for up to 19% Nd, 16% Pr and 25% Dy of each individual
419 rare earth produced in 2014 The overall supply of rare earths is
fore-420 casted to increase by a factor of 1.38 from 2014 to 2020[52] Assuming
421 that the share of neodymium, praseodymium and dysprosium remains
422 the same with respect to the overall REE supply in 2014, then the global
423 annual supply for these three elements will reach approximatively
424 29,100 tonnes Nd, 8725 tonnes praseodymium and 1940 tonnes Dy in
425 2020
426
If the composition of NdFeB will remain constant, the demand for
427 rare earths in 2020 in these three sectors will increase to a range of
428
2770–8290 tonnes Nd, 690–2075 tonnes Pr and 670–1450 tonnes Dy
429 The maximum demand/supply share in 2020 is projected to be about
430 28% for Nd, 24% for Pr and 75% for Dy It becomes evident that the
431 highest pressure in terms of material supply is expected for dysprosium
432
In particular, up to 56% of the estimated annual Dy supply in 2020
433 (today it is around 6%) would be needed to meet the deployment
434 targets for electric vehicles in 2020 This share is estimated at about
435 12% for Nd and Pr
436 Despite the fact that the production of rare earths and downstream
437 products will increase in the future, however the issue about REE supply
438 and price stability could re-emerge, thus posing a potential bottleneck
439
to the deployment targets for electric vehicles for 2020 and beyond
440 Opening a new primary production of rare earths is unrealistic in a
441 short time (about 8–10 years elapse between the discovery of rare
442 earths deposits and production at the mine) Mining and refining
443
of REE are associated with serious environmental problems, such
444
as soil and water contamination, human health, air pollution, etc
445 The environmental impact might also affect a sustainable production
446 and stable supply chain of rare earths Moreover, large volumes of
447 secondary rare earths production are not expected in the short term
448
to influence the demand/supply balance since many end-of-life
prod-449 ucts containing NdFeB magnet will enter the recycling circuit after
450 many years[59]
451 The spike in prices for rare earths during 2011–2012 and the
per-452 ceived risk associated with their supply and environmental pressure
453 have already led to investments in NdFeB-free motors and the adoption
454
of alternatives Such technologies can either use PM with a reduced
455 level of rare earths or replace the entire NdFeB-based component with
456 other types of drive system, such as an asynchronous motor Alternative
457 electric traction motors that do not require rare earths-based magnets
458 have already been developed for serial production by several
compa-459 nies The main reason for developing REE-free motors was security of
460 supply concerns rather than the price volatility of rare earths[52] In
461 the next section we evaluate the substitution paths for NdFeB-based
462 synchronous motors used in electric powertrains and analyse their
cur-463 rent technology status
Fig 5 Estimation of global annual demand for NdFeB magnet in EV, HEV and e-bike
applications in 2015 and 2020 and the percentage increase assuming that all traction
motors are based on NdFeB-PSM technology Bars correspond to average values The
error bar represents the standard error calculated based on the minimum and
maximum amount of NdFeB magnet used in PSM for each application.
t1:1 Table 1
t1:2 Typical composition of sintered NdFeB for applications at room temperature [62]
t1:3 Chemical element Percentage by weight
t1:4 Neodymium (Nd) and/or praseodymium (Pr) 29–32
t1:7 Aluminium (Al) 0.2–0.4
t1:9 Dysprosium (Dy) ⁎and/or terbium (Tb) 0.8–1.2
t1:10 ⁎ The Dy content could be increased up to 9% to allow the magnet to operate at high
t1:11 temperatures, i.e up to 200 °C.
5 C.C Pavel et al / Sustainable Materials and Technologies xxx (2017) xxx–xxx
Please cite this article as: C.C Pavel, et al., Role of substitution in mitigating the supply pressure of rare earths in electric road transport applications, (2017),http://dx.doi.org/10.1016/j.susmat.2017.01.003
Trang 6UNCORRECTED PR
OOF
464 4 Substitution opportunities of rare earths in electric traction
466 4.1 Rare earths substitution in NdFeB magnets and improved material
467 efficiency
468 At the moment there is no alternative magnet with similar
proper-469 ties to NdFeB or an approach that would enable the full substitution of
470 rare earths with less critical raw materials at large Such solutions may
471 still not be available in the near future Currently, research focuses mostly
472 on reducing the rare earth content through two main approaches:
473 (i) increasing material efficiency in magnet production (e.g grain
bound-474 ary diffusion processes), thus obtaining NdFeB magnets with less rare
475 earth content but with similar performance; (ii) optimising the motor
476 design, enabling high technical performance while using less NdFeB
478 Details about improving material efficiency and rare earths
substitu-479 tion in permanent magnets were already described by our group in the
480 context of NdFeB application in wind turbines[64] In summary, current
481 research indicates a possible reduction of the amount of Nd and Pr
482 needed to produce NdFeB For example, Lacal-Arántegui estimates a
483 rise in material efficiency for neodymium and praseodymium of up to
484 29% from 2015 to 2030 in a permanent magnet of equal magnetic
485 strength and cost[65]
486 As result of research developments, Daimler indicates that the Dy
487 content in permanent magnets in PHEV and HEV vehicles could signi
fi-488 cantly drop from 7.5–9% to approximately 5% in 2020 and afterwards to
489 2.5%[66] Terbium can replace dysprosium without losing performance,
490 but due to its higher price and a supply criticality issue it is not
consid-491 ered a convenient substitute
492 4.2 Reducing the amount of NdFeB magnet in electric traction motor:
493 dematerialisation
494 From the motor design side, high torque densities can be obtained in
495 optimised PSMs by designing new electrical machines while
simulta-496 neously using less NdFeB magnets[67] BMW developed a hybrid
497 motor using fewer magnetic materials embedded into salient rotor
498 structures This led to a reduction of the rare earths content (30% to
499 50% less) in the BMW i3 model compared to other PSM designs[42]
500 Since these motors provide both magnet and reluctance torques, they
501 are also called‘permanent magnet-assisted reluctance motors’ or just
502 ‘hybrid motors’[68] The hybrid motor is similar to the EU co-funded
503 MotorBrain project concept for PSM, which uses ferrite for creating
504 reluctance torque[69]
505 4.3 Component substitution for PSM traction motors in EVs and HEVs
506 Currently, most electric vehicles use PSMs with NdFeB magnets
507 These can be affixed to the rotor's surface (surface magnets) or they
508 can be located in pockets within the rotor (buried magnets) The stator
509 carries windings connected to the power supply to produce a rotating
510 magneticfield The torque results from the interaction between these
511 different magneticfields
512 Alternatives to NdFeB-PSM exist in serial production for several BEV
513 models For example, the Tesla S, Mercedes B-Class and Renault Twizy
514 have an asynchronous machine (ASM) and the Renault Zoe and Renault
515 Kangoo use an electrically excited synchronous machine (EESM)
How-516 ever, since hybrid vehicles have stricter requirements for a compact size
517 and temperature stability, the use of PSM motors is the preferred option
518 chosen by most manufacturers of HEV and PHEV
519 The ASM and EESM technologies are technically available and have
520 good performance, but they are not applied in serial HEV and PHEV
521 production because of their lower power density and higher weight
522 compared to PSM
523 Synchronous machines and ASM operate on different physical
524 principles In ASM, the torque is obtained by electromagnetic induction
525 from the magneticfield of the stator winding The AC Power is supplied
526
to the motor stator Whereas a synchronous motor rotor turns at the
527 same rate as the statorfield, an asynchronous motor rotor rotates at a
528 slower speed than the stator The induction motor stator magnetic
529 field therefore constantly changes relative to the rotor This induces
530
an opposing current in the rotor Thus, currents in the rotor windings
531
in turn create magneticfields in the rotor that react against the
532 statorfield The torque is a result of these different magnet fields The
533 ASM is also called“induction motor” as it bases on the principal of
534 induction
535 Externally excited EESMs only differ from PSMs in their rotor design
536 The PSM uses a permanent magnet in the rotor, whereas the EESM does
537 not use any magnets Electrical current from the battery magnetizes the
538 copper windings in the EESM rotor to create an electrical magnet
539 Other rare earths-free alternative motors are available and some are
540
in the prototype stage with a high potential for the future serial
produc-541 tion of EVs and HEVs Promising alternatives such as ASM with high
rev-542 olution per minute (rpm) and PSM with low-cost magnets (e.g ferrite
543 materials) have the potential to enter into the market for EVs and
544 HEVs Another substitute for PSM might be the switched reluctance
545 motor (SRM) if R&D can successfully solve significant technical
obsta-546 cles such as inverter incompatibility for other engines and high noise
547 due to very small sound-emitting air gaps
548 The current status, major advantages and disadvantages of the most
549 promising motor concepts as well as an outlook to 2020 are given in
550 Table 2
551
A crucial point in developing an electric vehicle is the improvement
552
of overall vehicle efficiency to allow longer operational ranges This
553 means that the efficiency of powertrain designs and their embedded
554 motors is a major issue for vehicle manufacturers Therefore, alternative
555 motor types have to compete with highly efficient PSMs The
compari-556 son shown inTable 2indicates that there is not an optimum substitute
557 for PSM that can satisfy all traction conditions while also fulfilling
558 technical and commercial requirements For instance, compared to
559 PSM, the ASM is less efficient in urban conditions, but more efficient
560
on motorways with high speed This characteristic is a strong advantage
561 for PSM and EESM types, making them more suitable for urban
applica-562 tions Other characteristics of the main technologies - PSM, ASM and
563 EESM are shown inTable 3
564 The industry aims at a higher driving range for EVs, which also
565 require a high efficiency at high speed Other motor types such as the
566 switched reluctance machine (SRM) and transverseflux machine
567 (TFM) are in early stage of development and further research is
neces-568 sary prior to serial production
569 The experts interviewed within this study believe that different
570 electric motor concepts will contribute to the future H&EV market
571 This observation is confirmed by a survey conducted by Hornick[80]
572 Manufacturers will favour a motor type that best meets the specific
573 needs of the vehicle at reasonable cost-effectiveness The ferrite
574 magnet-based motor and switched reluctance motor are potential
can-575 didates as these technologies may offer the lowest cost in car
manufac-576 ture compared to the relative high cost of NdFeB magnet-based PSM
577 [42] Since technical requirements vary with vehicle type and its area
578
of application, a variety of electric traction motors with specific
perfor-579 mance characteristics is needed for the development of efficient and
580 competitive H&EVs
581 The development time of a new electric motor for H&EVs highly
582 depends on economic conditions Based on the MotorBrain project,
583 which developed a new motor prototype in three years[69], we could
584 estimate that about 5 years are needed from the conceptual stage
585 until serial production The time could significantly decrease if electric
586 motor design has merely to be adapted from other similar applications
587 Given the variety of prototypes available today, it is expected that a rare
588 earth-free motor can be produced within a short time
Trang 7UNCORRECTED PR
OOF
t2:1 Table 2
t2:2 Overview of main component substitutes for PSM in EVs and HEVs, and comparison to current state-of-the art PSM.
t2:3 Motor type Rare earths content Current status Major advantages Major disadvantages Outlook 2020 Ref.
t2:4 Permanent synchronous motor (PSM) 0.56 kg REEs per EV motor ⁎
(less in HEV and e-bikes)
Used in all serial HEV and in most serial PHEV and BEV
• High efficiency at low and medium speeds
• Compact size/high power density
• Wide dissemination
• Dependency on rare-earth supply and their price variation
• Lower efficiency at high speed
Maintains a key role in EV and HEV as long
as the price of rare earths do not increase significantly
[41,48,49]
t2:5 Asynchronous motor (ASM) Rare earths free Used in some serial BEV (e.g.
Tesla S, Mercedes B class, Renault Twizy) and PHEV
• Low production costs
• Robustness
• High reliability
• High efficiency at high speed
• Lower efficiency than PSM in urban conditions
• Lower power density than PSM, requiring more package space and weight
• Higher copper demand than PSM
Maintains serial application in some EV and
in mild hybrids, partly as improved ASM with high rpm
[70,71]
t2:6 Externally excited synchronous
t2:7 motor (EESM)
Rare earths free Used in few serial BEV (e.g.
Renault Zoe) and PHEV Also available for HEV
• High efficiency in all speed ranges
• Lower power density than PSM
• More package space needed
• Complex structure resulting in high manufacturing costs
Remains an efficient alternative to PSM, but application in HEV is unlikely
[42,72]
t2:8 ASM with high rpm Rare earths free Serial production announced • Potential for high
ener-gy and material effi-ciency
• Potential for low pro-duction costs
• No experience in serial production yet Offers high potential for serial production in
BEV, HEV and PHEV due to high efficiency and good cost effectiveness
[42,73]
t2:9 PSM with low-cost magnets Rare earths free Prototypes using ferrite or
AlNiCo magnets
• Potential for good over-all performance
• No experience in serial production Offers good potential for serial production
due to high technical performance and reasonable cost effectiveness
[68,74–76]
• Potential for cheap en-gine production
• High noise level
• Requirement for a specific inverter, which
is not compatible to production lines of power electronics for other engines
Needs further R&D to achieve highly efficient and silent engines suitable for serial production
[41,77]
density and efficiency
• Low technology readiness level Might offer high power density and high
efficiency, but needs more intense R&D
[78,79]
t2:12 Hybrid motor (e.g combine
t2:13 synchronous reluctance principle
t2:14 with permanent excitation)
0.37 kg ⁎⁎REEs or less
per motor
Used in the BEV BMW i3 and PHEV BMW 7
• Similar performance as PSM with less rare earths
• Remaining rare earth demand Applied in serial BMW i3 and BMW 7 PHEV
production with high potential for further vehicle types and models
[68,69]
t2:15 ⁎ The rare earths content in PSM takes into consideration the range of 1–2 kg permanent magnet per EV traction motor and the following chemical composition of NdFeB: 30% Nd/Pr (Nd:Pr = 4:1) and 7.5% Dy.
t2:16 ⁎⁎ Value relates to 1 kg NdFeB magnet per traction motor with the same chemical composition as above.
Trang 8UNCORRECTED PR
OOF
589 There are no alternatives to PSM for e-bikes available on a large
pro-590 duction scale Since the current, low rare earth prices give no incentive
591 to manufacturers to develop rare earth-free motors for e-bikes, it seems
592 that industry does not look for alternative solutions that might be
593 accompanied by efficiency losses or higher e-bike weight This
assump-594 tion is confirmed by industry experts Several European manufacturers,
595 e.g Bosch, Brose Antriebstechnik, Derby Cycle located in Germany and
596 Accell Group from the Netherlands, supply high-quality e-bikes to
597 customers who demand high energy efficiency and light powertrains
598 Consequently, the competitiveness of these manufacturers highly relies
599 on the production of premium products Future shortages or high prices
600 of rare earths might be tackled by the fast development of alternative
601 motor systems This is evident in e-bike motors that have mostly been
602 derived from automotive applications like electric power steering or
603 windshield wiper motors
604 5 Impact of substitution on short-term demand for critical rare
605 earths– Nd, Pr and Dy – in H&EV and e-bike applications
606 Future developments in material efficiency, motor design and
607 component substitution may make the challenge associated with rare
608 earths supply and environmental issue less daunting There are
609 expected improvements in terms of efficiency in rare earths usage for
610 production of NdFeB magnets Although the full substitution of rare
611 earths will probably not take place over the coming years, experts
612 consider that the share of Nd and Pr in NdFeB composition may decrease
613 down to 26.5% Nd/Pr from 30% by 2020 Furthermore, a significant drop
614 from 7.5% down to approximatively 5% of the Dy content in NdFeB
615 magnets looks to be feasible for PHEVs and HEVs An optimised PSM
616 design could lead to the use of much less NdFeB magnets (i.e as in the
617 case of the hybrid design used in BMW's i3 motor) Moreover, some
618 manufacturers may continue with or switch to rare earths-free motors
619 for BEVs There are also pilot concepts of REEs-free motors for hybrid
620 vehicles (PHEV and HEV) with a high potential for commercialisation
621 Due to the large number of parameters and the high uncertainty of
622 future technological and economic developments, the precise future
623 penetration rate of substitutions remains unclear Current low prices
624 and a sufficient supply of rare earths give no strong incentive to switch
625
to rare earth-free motors, unless they become more cost and
626 performance-effective In this context, experts see a high potential for
627 the newly developed ASM with high rpm, which has high efficiency
628 and could also achieve low production costs
629 Based on possible technological developments and inputs received
630 from experts, in this paper we have analysed different substitution
631 scenarios along three main parameters: materials efficiency,
632 dematerialisation (less NdFeB content) and component substitution
633 (replacement of PSM by other rare earth-free technology) We grouped
634 them in 4 case scenarios: (i) substitution case A, takes into account an
635 increase in material efficiency; (ii) substitution case B, considers the
636 material efficiency of case A and 30% of component substitution,
637 (iii) substitution case C, on top of the material efficiency of case A it
638 assumes 50% component substitution, and (iv) substitution case D
639 adds dematerialization (i.e 40% less NdFeB magnet on top of case C
640 Table 4gives an overview on the assumptions of the four substitution
641 scenarios and compares them to the reference scenario, which exhibits
642
no substitution and features the same NdFeB demand as shown inFig 5
643 The results obtained from this analysis are presented inFig 6
644 The impact of substitution is revealed through the four different
645 scenarios A, B, C and D The results show that substitution has the
poten-646 tial to reduce the short-term global demand for rare earths in the H&EV
647 and e-bikes sectors Compared to the 2020 reference case a decreasing
648 demand by 12% for Nd and Pr can be achieved by improving material
649
efficiency (substitution case A) This reduction can be more significant
650 (from 38% up to 56%) if an adoption of alternative components
comple-651 ment the material efficiency (e.g 30% or 50% of PSM technology are
652 replaced by rare earth-free electric traction motors as evidenced in
653 substitution case B and C, respectively) If the decrease of NdFeB amount
654 (through dematerialisation) will also take place, the reduction in Nd
655 and Pr demand can reach about 73% (substitution case D)
656
In case of Dy a substantial demand reduction (up to 33%) in H&EVs
657 can be reached just by improving material efficiency, such as by
658 decreasing the Dy loading in the magnet from 7.5% to 5% A decreasing
659
of Dy loading below 5% in NdFeB used in electric traction motors for
660 serial production of electric and hybrid vehicles will likely not take
661 place before 2020 Material efficiency has no impact on e-bikes, which
662 already use a very small loading (1% Dy) Moreover, if 30% of the rare
663 earths' components is replaced, the demand for Dy in electric vehicles
664 could be reduced by half (substitution case C) with respect to the
665
2020 reference case, decreasing further by 80% in case of substitution
666 case D
667 While already in the case of substitution case B the demand for rare
668 earths in 2020 might decrease below the 2015 level in HEV and e-bikes,
669 however even in the most ambitious substitution scenario (D) the
670 growth rate for Nd, Pr and Dy consumption in electric vehicle sector is
671 expected to increase over the next 5 years in order to meet the
t4:1 Table 4
t4:2 Possible substitution scenarios for rare earths in PSM used in H&EV and e-bikes.
t4:3 Substitution scenario - 2020 Material efficiency Dematerialisation Component
substitution (%)
Dy loading ⁎⁎in
PM (H&EVs) (%)
t4:8 Substitution case A (material efficiency) 26.5 5 0 0
t4:9 Substitution case B (material efficiency + low component substitution) 26.5 5 0 30
t4:10 Substitution case C (material efficiency + high component substitution) 26.5 5 0 50
t4:11 Substitution case D (material efficiency + high component substitution +
t4:12 dematerialisation)
26.5 5 Reduction of NdFeB amount
by 40% ⁎⁎⁎ 50
t4:13 ⁎ Nd and Pr are found in ratio 4:1.
t4:14 ⁎⁎ Dy loading in e-bikes is considered 1% in all cases.
t4:15 ⁎⁎⁎ 40% magnet reduction leads to 0.6–1.5 kg NdFeB/electric car and 36–210 g NdFeB/e-bike.
t3:1 Table 3
t3:2 Comparison of principal characteristics of PSM, ASM and EESM [78]
t3:4 Construction space ++ + +
t3:7 Production costs + ++ +
t3:11 ++ very good performance; + good performance; O low performance.
Trang 9UNCORRECTED PR
OOF
672 deployment targets set for 2020 This demand is estimated to be at least
673 3 times more in case of the substitution case D, compared to over 13% in
674 the reference scenario without any substitution
675 The growing demand for rare earths indicates a need for further
ac-676 tions to ensure a secure supply and development of suitable alternatives
677 for rare earths-based PM traction motors This will allow Europe and
678 other countries to accomplish the overall goals of cutting CO2emissions
679 and reducing the transport sector's dependence on oil
680
6 Conclusions
681 Despite the benefits of climate change mitigation and from potential
682 fuel savings, several barriers could hinder the widespread adoption of
683 electric vehicles Among them is the potential supply disruption of
684 critical rare earths for NdFeB magnet-based electric traction motors In
685
2015, the global EV sector consumed around 1% of the total market for
686 NdFeB magnets Driven by efforts to foster EVs adoption and meet
687 ambitious deployment targets of EVs in 2020, the demand for NdFeB
688 could rapidly and significantly increase over the next few years HEVs
689 and e-bikes further compete with EVs for NdFeB-based PSM
690
We estimate that the H&EV and e-bike sectors combined would
691 require over two times more NdFeB magnets in 2020 compared to
692
2015 (between 11,500–34,500 tonnes NdFeB), representing up to 30%
693
of expected global NdFeB supply in 2020 Moreover the market for
694 rare earths-based permanent magnets will likely grow for other
appli-695 cations, e.g high-tech and energy-devices The overall rising demand
696 for NdFeB magnets could have important implications on the supply
697 chain for rare earth, which may also lead to pricefluctuation Dy poses
698 the highest supply risk as up to 75% of its 2020 supply may be required
699
to meet the global electric road transport applications
700 The potential supply risks associated with rare earths for electric
701 road transport applications cannot be easily mitigated as there are no
702 effective substitutes for the rare earths used in permanent magnets
703 However higher material efficiency, dematerialisation and adoption of
704 alternative components, e.g rare earths-free electric traction motors,
705 can attenuate the future increasing demand for rare earths Adoption
706
of different substitution paths should take place in parallel as it does
707 not appear that one substitution method prevails over the others
708 Under the most optimistic substitution scenario, which implies
709 adoption of different types of substitution, the global demand in 2020
710 for H&EV applications could be drastically reduced by 75% for Nd and
711
Pr, and 80% for Dy versus a reference without substitution in the same
712 year But even if such optimistic scenario was to be successfully
imple-713 mented, the global annual demand for rare earths in electric traction
714 motors in electric vehicle applications is expected to grow significantly
715
up to 2020 This calls for an integrated‘security-of-supply’ policy that
716 need to consider various strategies along secure access, recycling and
717 substitution For Europe and other countries/regions that lack domestic
718 supplies, substitution may be an effective short-term solution This
719 paper reveals that a number of high potential options for PMS exist
720 and they could be rapidly brought to commercialisation, should prices
721 for rare earths increase However more R&D investments are needed
722
to further develop these solutions and to search for even better
723 alternatives
724 Acknowledgements
725 This work is part of a research project funded by theEuropean Q2
726 Commission The authors are thankful to various experts from the
727 automotive industry for providing their valuable inputs
728 References
729
[1] International Energy Agency Report, World Energy Outlook, 2015.
730
[2] United Nations Framework Convention on Climate Change, Paris declaration on
731
electro-mobility and climate change & call to action, http://newsroom.unfccc.int/
732 media/521376/paris-electro-mobility-declaration.pdf 2015 (accessed 11.05.16).
733
[3] European Commission, Energy Union Package — A Framework Strategy for a
Resil-734
ient Energy Union With a Forwards-looking Climate Change Policy, COM(2015)80
735
Final(Brussels) 2015.
736
[4] International Energy Agency, Global EV Outlook 2016, Beyond one million electric
737
cars,
http://www.iea.org/publications/freepublications/publication/Global_EV_Out-738 look_2016.pdf 2016 (accessed 02.06.16).
739
[5] International Energy Agency, Global EV Outlook, Understanding the electric vehicle
740
landscape to 2020, https://www.iea.org/publications/freepublications/publication/
741 GlobalEVOutlook_2013.pdf 2013 (accessed 11.05.16).
742
[6] Amsterdam Round Tables and McKinsey & Company, EVolution: Electric vehicles in
743
Europe – Gearing up for a new phase? https://www.google.nl/url?sa=t&rct=j&q=
744
&esrc=s&source=web&cd=1&ved=
Fig 6 Estimation of global annual demand for Nd, Pr and Dy in 2015 and 2020 in electric
traction motors for H&EVs and e-bikes under different substitution scenarios Bars
correspond to average values The error bar represents the standard error calculated
based on the minimum and maximum amount of NdFeB magnet used in PSM for each
application.
9 C.C Pavel et al / Sustainable Materials and Technologies xxx (2017) xxx–xxx
Please cite this article as: C.C Pavel, et al., Role of substitution in mitigating the supply pressure of rare earths in electric road transport applications, (2017),http://dx.doi.org/10.1016/j.susmat.2017.01.003
Trang 10UNCORRECTED PR
OOF
746 mckinsey.com%2F~%2Fmedia%2FMcKinsey%2520Offices%2FNetherlands%2FLatest%
747 2520thinking%2FPDFs%2FElectric-Vehicle-Report-EN_AS%2520FINAL.ashx&usg=
AFQjCNHD4p87eDheWXdnekdbp2Un1A7XiA&sig2=w0r_9lE64QRl-749 yoSfLNA3Q&cad=rja 2014 (accessed 11.05.16).
750 [7] California Institute of Technology, Resnick institute report Critical materials for
sus-751 tainable energy applications, http://resnick.caltech.edu/docs/R_Critical.pdf 2011
752 (accessed 12.05.16).
753 [8] World Wide Fund – WWF, Critical materials for the transition to a sustainable energy
754 future, http://www.ecofys.com/files/files/wwf-ecofys-2014-critical-materials-report.
755 pdf 2014 (accessed 12.05.16 D:\Programs\SPS\WMS2016\repos\LC85\smt00036\12.
757 [9] UK Energy Research Centre, Materials availability for low-carbon technologies: an
758 assessment of the evidence, http://www.ukerc.ac.uk/asset/34D2BFC5%2D9C0D%
759 2D4C07%2DBA6CD6D15BDE549A/ 2014 (accessed 12.05.16).
760 [10] M.L Bustamante, B Hubler, G Gaustad, C.W Babbitt, Life cycle assessment of jointly
761 produced solar energy materials: challenges and best practices, Sol Energy Mater.
762 Sol Cells 156 (2016) 11–26.
763 [11] R.L Moss, E Tzimas, H Kara, P Willis, J Kooroshy, Critical metals in strategic
764 energy technologies — assessing rare metals as supply-chain bottlenecks in
765 low-carbon energy technologies, European Commission, Joint Research Centre,
766
769 PDF&CatalogueNumber=LD-NA-24884-EN-N 2011 (accessed 12.05.16).
770 [12] R.L Moss, E Tzimas, H Kara, P Willis, J Kooroshy, The potential risks from metals
771 bottlenecks to the deployment of strategic energy technologies, Energ Policy 55
772 (2013) 556–564.
773 [13] R.L Moss, E Tzimas, P Willis, J Arendorf, L Tercero Espinoza, Critical metals in the
774 path towards the decarbonisation of the EU energy sector— assessing rare metals as
775 supply-chain bottlenecks in low-carbon energy technologies, European
Commis-776 sion, Joint Research Centre, https://setis.ec.europa.eu/sites/default/files/reports/
777 JRC-report-Critical-Metals-Energy-Sector.pdf 2013 (accessed 12.05.16).
778 [14] Y Zhang, T Ma, X Liu, P Liu, J Jin, J Zou, M Yan, Coercivity enhancement of Nd-Fe-B
779 sintered magnets with intragranular adding (Pr, Dy, Cu)-H x powders, J Magn Magn.
780 Mater 399 (2016) 159–163.
781 [15] J.-R Riba, C López-Torres, L Romeral, A Garcia, Rare-earth-free propulsion motors for
782 electric vehicles: a technology review, Renew Sust Energ Rev 57 (2016) 367–379.
783 [16] K.S Stegen, Heavy rare earths, permanent magnets, and renewable energies: an
im-784 minent crisis, Energ Policy 79 (2015) 1–8.
785 [17] J Lucas, P Lucas, T Le Mercier, A Rollat, W Davenport, Permanent Magnets Based
786 on Rare Earths: Fundamentals, in Rare Earths — Science, Technology, Production
787 and Use, Elsevier B.V, 2015 213–230.
788 [18] European Rare Earths Competency Network (ERECON), Strengthening of the
789 European rare earths supply chain — challenges and policy options,
http://ec.euro-790
pa.eu/DocsRoom/documents/10882/attachments/1/translations/en/renditions/na-791 tive 2015 (accessed 12.05.16).
792 [19] E Alonso, A.M Sherman, T.J Wallington, M.P Everson, F.R Field, R Roth, R.E.
793 Kirchain, Evaluating rare earth element availability: a case with revolutionary
de-794 mand from clean technologies, Environ Sci Technol 46 (2012) 3406–3414.
795 [20] K Nansai, K Nakajima, S Kagawa, Y Kondo, S Suh, Y Shigetomi, Y Oshita, Global
796 flow of critical metals necessary for low-carbon technologies: the case of
neodymi-797 um, cobalt, and platinum, Environ Sci Technol 48 (2014) 1391–1400.
798 [21] M.A De Boer, K Lammertsma, Scarcity of rare earths elements, ChemSusChem 6
799 (2013) 2045–2055.
800 [22] L Baldi, M Peri, D Vandone, Clean energy industries and rare earth materials:
eco-801 nomic and financial issues, Energ Policy 66 (2014) 53–61.
802 [23] A Golev, M Scott, P.D Erskine, S.H Ali, G.R Ballantyne, Rare earths supply chain:
803 current status, constraints and opportunities, Resour Policy 41 (2014) 52–59.
804 [24] K Habib, H Wenzel, Exploring rare earths supply constraints for the emerging clean
805 energy technologies and the role of recycling, J Clean Prod 84 (2014) 348–359.
806 [25] S Massari, M Ruberti, Rare earth elements as critical raw materials: focus on
inter-807 national markets and future strategies, Resour Policy 38 (2013) 36–43.
808 [26] B Achzet, C Helbig, How to evaluate raw material supply risk — an overview,
809 Resour Policy 38 (2013) 435–447.
810 [27] S Glöser, L.T Espinoza, C Gandenberger, M Faulstich, Raw material criticality in the
811 context of classical risk assessment, Resour Policy 44 (2015) 35–46.
812 [28] European Commission, Report on critical raw materials for the EU, http://ec.europa.
813
eu/DocsRoom/documents/10010/attachments/1/translations/en/renditions/na-814 tive 2014 (accessed 12.05.16).
815 [29] US Department of Energy, Critical materials strategy, http://energy.gov/sites/prod/
816 files/DOE_CMS2011_FINAL_Full.pdf 2011 (accessed 12.05.16).
817 [30] M Goe, G Gaustad, Identifying critical materials for photovoltaic in the US: a
multi-818 metric approach, Appl Energy 123 (2014) 387–396.
819 [31] J.H Rademaker, R Kleijn, Y Yang, Recycling as a strategy against rare earth element
820 criticality: a systemic evaluation of the potential yield of NdFeB magnet recycling,
821 Environ Sci Technol 47 (2013) 10129–10136.
822 [32] L.T Peiró, G.V Méndez, R.U Ayres, Material flow analysis of scares metals: sources,
823 functions, end-uses and aspects for future supply, Environ Sci Technol 47 (2013)
824 2939–2947.
825 [33] T.E Graedel, E.M Harper, N.T Nassar, B.K Reck, On the materials basis of modern
so-826 ciety, PNAS 112 (2015) 6295–6300.
827 [34] N.T Nassar, Limitation to elemental substitution as exemplified by the
platinum-828 group metals, Green Chem 17 (2015) 2226–2235.
829 [35] C.C Pavel, A Marmier, E Tzimas, T Schleicher, D Schüler, M Buchert, D Blagoeva,
830 Critical raw materials in lighting applications: substitution opportunities and
impli-831 cation on their demand, Phys Status Solidi A 216 (2016) 2937–2946.
832 [36] B.J Smith, R.G Eggert, Multifaced material substitution: the case of NdFeB magnets,
833 2010–2015, JOM 7 (2016) 1964–1971.
834 [37] T.E Graedel, Material substitution: a resource supply perspective, Resour Conserv.
835 Recycl 34 (2002) 107–115.
836
[38] R.U Ayres, On the practical limits to substitution, Ecol Econ 61 (2007) 115–128.
837
[39] E Nakamura, K Sato, Managing the scarcity of chemical elements, Nat Mater 10
838
(2011) 158–161.
839
[40] D Powell, Sparing the rare earths: potential shortages of useful metals inspire
840
scientists to seek alternatives for magnet technologies, Sci News 180 (2011) 18–21.
841
[41] L Kumar, S Jain, Electric propulsion system for electric vehicular technology: a
re-842
view, Renew Sust Energ Rev 29 (2014) 924–940.
843
[42] J.D Widmer, R Martin, M Kimiabeigi, Electric vehicle traction motors without rare
844
earth magnets, Sustain Mater Technol 3 (2015) 7–13.
845
[43] O Gutfleisch, M.A Willard, E Brück, C.H Chen, S.G Sankar, J.P Liu, Magnetic
mate-846
rials and devices for the 21st century: stronger, lighter, and more energy efficient,
847
Adv Mater 23 (2011) 821–842.
848
[44] J Speirs, Y Houari, M Contestabile, R Gross, B Gross, Materials availability:
849
potential constrains to future low-carbon economy Working paper II: batteries,
850
magnets and materials, UKERC/WP/TPA/2013/003, http://www.ukerc.ac.uk/asset/
851 F21105AE%2D78A7%2D4E9C%2D88C752A2149C8B54/ 2013 (accessed 13.05.16).
852
[45] C Thiel, J Krause, P Dilara, Electric vehicles in the EU from 2010 to 2014 — is full
853
scale commercialisation near?, Joint Research Centre — science and policy report,
854 https://setis.ec.europa.eu/sites/default/files/reports/Electric_vehicles_in_the_EU.
855 pdf 2015 (accessed 23.05.16).
856
[46] Fraunhofer IAO, Strukturstudie BWe mobil 2011,
http://wiki.iao.fraunhofer.de/im-857 ages/studien/strukturstudie-bwe-mobil-2011.pdf 2011 (accessed 23.05.16).
858
[47] CRM_Innonet, Substitution of Critical raw Materials, Deliverable Report D5.3 Final
859
Roadmap Report, 2015.
860
[48] J Paulsen, Developing concepts in e-motor technology, online publication on
re-861
source centre for 3rd international conference advanced E-motor technology,
862
Frankfurt (Germany), http://www.e-motor-conference.com/media/1000786/
863 35833.pdf 2015 (accessed 13.05.16).
864
[49] P Els, Perfecting the electric vehicle drive motor, online publication on resource
865
centre for 3rd international conference advanced E-motor technology, Frankfurt
866
(Germany), http://www.e-motor-conference.com/media/1000786/35836.pdf 2015
867
(accessed 13.05.16).
868
[50] INSG insight, The global e-bike market,
http://www.insg.org/%5Cdocs%5CINSG_In-869 sight_23_Global_Ebike_Market.pdf 2014 (accessed 25.05.16).
870
[51] W.T Benecki, The permanent magnet market — 2015 Presentation at the
confer-871
ence magnetics Orlando, Florida,
http://www.waltbenecki.com/uploads/Mag-872 netics_2013_Benecki_Presentation.pdf 2013 (accessed 20.05.16).
873
[52] Roskill Information Services, Rare Earths: Market Outlook to 2020, 15th ed., 2015.
874
[53] S Shepard, L Jerram, Electric vehicle market forecasts, global forecasts for light duty
875
hybrid, plug-in hybrid, and battery electric vehicles sales and vehicles in use:
876
2015–2024, Navigant researchPublished 4Q 2015 https://www.navigantresearch.
877 com/wp-assets/brochures/MD-EVMF-15-Executive-Summary.pdf 2015 (accessed
878
28.06.16).
879
[54] International Energy Agency, Hybrid & electric vehicles-implementing agreement
880
(IA-HEV) Hybrid and electric vehicles — the electric drive commutes, http://
881 www.ieahev.org/assets/1/7/2016_IA-HEV_BOOK_web_%281%29.pdf 2015 (accessed
882
28.06.16).
883
[55] Y Zhou, E-drive vehicle sales analyses, http://energy.gov/sites/prod/files/2015/07/
884 f24/van011_Zhou_2015_p.pdf 2015 (accessed 23.05.16).
885
[56] M Buchert, et al., Ressourceneffizienz und ressourcenpolitische Aspekte des
886
Systems Elektromobilität Arbeitspaket 7 des Forschungsvorhabens OPTUM:
887
Optimierung der Umweltentlastungspotenziale von Elektrofahrzeugen,
Oeko-888
Institut e.V., Daimer AG, TU Clausthal, Umicore, http://www.oeko.de/oekodoc/
889 1334/2011-449-de.pdf 2011 (accessed 23.05.16).
890
[57] The Boston Consulting Group, Powering autos to 2020 The era of the electric cars?
891 https://www.bcg.com/documents/file80920.pdf 2011 (accessed 23.05.16).
892
[58] EU FP7 Marie-Curie Initial Training Network (EREAN), E-bikes and rare earths,
893 http://erean.eu/wordpress/e-bikes-and-rare-earths/ 2015 (accessed 02.12.2016).
894
[59] S Hoenderdaal, L.T Espinosa, F Marscheider-Weidemann, W Graus, Can a
895
dysprosium shortage threaten green energy technologies? Energy 49 (2013)
896
344–355.
897
[60] PRNewswire, Global E-bike market 2015–2019, http://www.prnewswire.com/
898 news-releases/global-e-bike-market-2015-2019-300018143.html 2015 (accessed
899
26.05.16).
900
[61] European Commission, Report on critical raw materials for the EU Critical raw
ma-901
terials profiles, http://ec.europa.eu/DocsRoom/documents/11911/attachments/1/
902 translations/en/renditions/native 2014 (accessed 20.05.16).
903
[62] E-Magnets UK, How neodymium magnets are made, http://www.ndfeb-info.com/
904 neodymium_magnets_made.aspx (accessed 05.12.16).
905
[63] K Binnemans, P.T Jones, B Blanpain, T van Gerven, Y Yang, A Walton, M Buchert,
906
Recycling of rare earths: a critical review, J Clean Prod 51 (2013) 1–22.
907
[64] C.C Pavel, R Lacal-Arántegui, A Marmier, E Tzimas, D Schüler, M Buchert, D.
908
Blagoeva, Role of rare earths in permanent magnets and review of substitution
op-909
portunities in wind turbines, Manuscript submitted for publication to Renew
Sus-910
tain Energy Rev (2016) (MS Ref No RSER-D-16-01647).
911
[65] R Lacal-Arántegui, Materials use in electricity generators in wind turbines —
state-912
of-the-art and future specification, J Clean Prod 87 (2015) 275–283.
913
[66] K Ruland, Daimler AG, Personal Communication, 2015.
914
[67] J Widmer, EV eMotors without rare earth materials Newcastle University, http://
915
cdn.awsripple.com/www.criticalrawmaterials.eu/uploads/14-05-07-J-Widmer-916 CRM-Workshop-Rare-Earth-FINAL.pdf 2014 (accessed 24.05.16).
917
[68] Green Car Congress press release, BMW's hybrid motor design seeks to deliver high
918
efficiency and power density with lower rare earth use, http://www.
919 greencarcongress.com/2013/08/bmw-20130812.html 2013 (accessed 24.05.16).
920
[69] MotorBrain press release, Compact and efficient electromotor without rare earth
921
metals The “MotorBrain” research team presents the first prototype at the
Hanno-922
ver Messe 2014, http://www.motorbrain.eu/ 2014 (accessed 24.05.16).
923
[70] E-mobil BW, Fraunhofer institute for industrial engineering (IAO): structure study
924
BW e
mobile 2011: Baden-Württemberg on the way to electromobility, http://
925 www.e-mobilbw.de/files/e-mobil/content/DE/Service/Publikationen/e-papers/e_
926 mobil_structure_study_en/files/mobile/index.html#1 2011 (accessed 24.05.16).