Vehicle Batteries in China and Germany

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2 A Study on: Vehicle Batteries in China and Germany Commissioned as part of the German Chinese Sustainable Fuel Partnership (GCSFP) Date: Project participants: German project leader: Fuel Cell and Battery Consulting (FCBAT), Prof. Dr. habil. Jürgen GARCHE German project partners: Hoppecke Batterien GmbH & Co KG., Dr. Bernhard RIEGEL Institute for Power Electronics and Electrical Drives (ISEA) of RWTH Aachen, Prof. Dr. Dirk Uwe SAUER Chinese project leader: China Electronics Technology Group Co. No. 18 th Research Institute, Dr. Chengwei XIAO

3 Executive Summary This document has been written in the framework of the German-Chinese Sustainable Fuel Partnership (GCSFP). The aim of this study is to describe the stateof-the-art in battery development for different types of EVs in China and in Germany in order to provide a basis for further mutual cooperation. Chapter 1 Introduction This chapter gives an overview about the history and the general state-of-the-art of the battery development in both countries. Chapter 2 Demand on Propulsion Batteries for Cars This chapter describes the battery requirements of different types of electric vehicles, i.e. Hybrid Electric Vehicle (HEV), Plug-In Hybrid Electric Vehicle (PHEV), Extended Range Electric Vehicle (EREV), Battery Electric Vehicle (BEV), Fuel Cell - Hybrid Electric Vehicle (FC-HEV) and Fuel Cell - Plug-In Electric Vehicle (FC-PHEV). In general the focus is on the Li-ion battery, but for HEVs also Ni-MH batteries and advanced lead-acid batteries are considered. Chapter 3 Battery Tests This chapter describes battery test procedures and battery test conditions used in China and Germany and also other countries. It is arranged in a performance part (capacity/energy, power, self discharge, charge, efficiency), a life time part and a safety and abuse part (electrical safety: overcharge, overdischarge, short circuit; physical abuse: mechanical abuse [drop test, penetration test] and thermal abuse). The basic structure of the German and the Chinese test procedures is in a first approximation the same. In detail, however, there are differences. Both parties should work out a common position for the development of international ISO and IEC battery test procedures.

4 Chapter 4-6 Battery Development in China / Germany / other countries The aim of the chapters 4, 5, and 6 is to give information about batteries and not to give an assessment, which would be difficult as long as it would be based on information gathered from different sources without any practical confirmation tests. The chapters 4, 5, and 6 are concentrating on cells with higher capacity ( 5 Ah). It is, however, to be noticed that also in the next years consumer cells will be still used for EVs caused by their relatively low costs. Therefore also information is given about consumer cells. These 3 chapters give information about the battery development in China, Germany, and other relevant countries. In the beginning of all three chapters it is to find an overview about the most important traction battery companies and R&D institutes which are involved in battery development. Then a description about traction batteries (Li-ion, Ni-MH, and Lead-acid) follows. Unfortunately only few detailed overviews about battery data were received from the companies and literature. Therefore it was created a standard table with the most important data of the battery such as voltage, capacity, energy and power values, dimension, mass etc. in order to give the possibility to compare the different batteries in a first approximation. A detailed overview on few batteries is given in the appendix. Furthermore it is to mention that some companies haven t given any information about their products. Nevertheless the authors believe that the study represents the current state-of-the-art in the traction battery area. Even if not all battery data are available, it is not expected, that market-near new battery systems are missing. Available battery data are mostly given only for battery products which are already on the market e.g. for power tools or portable applications. Data on the newest developments for the automotive sector are rarely published. In general it is to assess that in China a mature Li-ion technology exists with high capacity in the consumer battery area. Nearly ½ of the world Li-ion battery production is located in China. This consumer cell technology know-how is already transferred to the EV battery area. There are pilot lines for EV batteries which have still manual assembly steps. These pilot lines are capable of being converted to mass-production lines.

5 In Germany such technology level is not yet reached at this time. There are prototype batteries with good electrical parameters but with relatively high costs. However, Germany is a large supplier of Li-battery components (see appendix 9.5.2). The Chinese cost are about 30 % lower, due to production via modern pilot lines, relatively low material costs (own production) and low labor costs. Besides China, also Japan and Korea belong to the market leaders in the Li-ion battery development and production. These three countries are the current benchmark. Battery Development in China The following table gives a quantitative overview about Chinese cells/batteries, which are described in more detail in chapter 4. Table 1: Overview about described Chinese cells/batteries Battery System Number of producers Number of cells Cell (battery) capacity (batteries) Li-Ion Ah Ni-MH Ah Advanced Lead-Acid 1 (1) (60 Ah) Battery Development in Germany The following table gives a quantitative overview about German cells/batteries described in more detail in chapter 5. Table 2: Overview about described German cells/batteries Battery System Number of producers Number of cells (batteries) Li-Ion 5 13 (3) Cell capacity 5 60 Ah (12V/30Ah, 24V/30Ah, 24V/40Ah) Ni-MH Ah, Ah Advanced Lead-acid 4 (10) ( Ah) Battery Development in other countries The following table gives a quantitative overview about cells / batteries coming from the other countries beside China and Germany (mainly from USA, Japan, and Korea) and which are described in more detail in chapter 6.

6 Table 3: Overview about cells/batteries from countries beside China and Germany Battery System Number of producers Number of cells Cell capacity Li-Ion Li-Polymer (1 battery) Ah (31 V/50 Ah) Ni-MH Ah Advanced Lead-acid 3 (3 batteries) (12 V Ah 150 V/6 Ah) ZEBRA V/64 Ah Worldwide Lithium Resources and Lithium-Battery Recycling The demand on Li (used as Li 2 CO 3 ) until 2020 for Li-batteries is as follows: - Germany plans to introduce 1 mil. BEVs until 2020 i.e Tt Li 2 CO 3 -supply. - China plans to introduce 4.7 mil. BEVs until i.e Tt. Li 2 CO 3 -supply. - Worldwide it is expected to have a car production of about 100 mil. cars per annum with about 3 % BEVS (3 mil. cars) in 2020, i.e Tt Li 2 CO 3 are needed annually. Today s annual production of Li amounts to about 100 Tt Li 2 CO 3, which is used in different industries. Therefore the Li production has to increase strongly. Fortunately there are enough Li 2 CO 3 resources, which are given between 20 and 160 mil. t. Beside the increase of the Li 2 CO 3 raw material production also the recycling capacities of Li-batteries have to increase. China addressed that problem in the framework of the 863 programme and Germany in the framework of the economy stimulation package 2. Chapter 7 Energy Supply for Electric Vehicles This chapter takes a look on the main questions which are related to the electric energy supply for EVs (PHEV, EREV, and BEVs). 7.1 Energy Demand for EVs For Germany, it is estimated to have about 1 mil. EVs (2 %) in 2020, i.e. 3,2 TWh / 0.5 % of the today annual electrical energy consumption (590 TWh) will be necessary if all EVs are BEVs. Especially if a "controlled charge" (where the power-supply industry determines the charge time) is used, about 18 mil. EVs could be driven without any increase of the power station capacity.

7 In China it is expected to have about mil. EVs (3-5 %) in 2020, which is related to an annual electrical energy demand of 9-15 TWh, that is about % of the today annual electrical energy generation (6.400 TWh). 7.2 CO 2 Emissions The CO 2 emission of EVs is zero on a Tank-to-Wheel (TTW) basis. On a Well-to- Wheel (WTW) basis, however, the sources of the power generation mix must be taken into consideration (see next Table). Well-to-wheel CO 2 emission for a BEV (compact class) with Li-ion Battery, NEDC (Table 43) EU-Mix Germany China France USA Japan g CO 2 /km Grid buffering From theoretical point of view, an additional benefit of EVs could be the storage of the fluctuating renewable energies and peak shaving. This grid buffering is also called vehicle-to-grid (V2G) option. The grid control could be related to energy service (compensation of low or zero renewable output) and power service (contribution to peak power). In short and middle time scale, however, these benefits are small, caused by the low total EV battery capacity. It must be pointed out, that all V2G considerations are assuming that the lifetime of batteries is large enough to meet both the mobility and the grid demand. At present and in the near future, however, this would not be given. The overnight recharge, as the preferred charge option for EVs and BEVs batteries, is a contribution to the grid buffering too. 7.4 Infrastructure for Electric mobility It is important to standardize the charge hardware as early as possible. The main charge option is the household outlet with the common limitations of 230 V -16 A. For BEV having only the battery as energy source, fast charge based on 400 V is desirable. For fast charge about 10% charge losses in form of heat are to be taken into account. Therefore for fast charge a battery cooling is recommended. At higher charge power, a liquid cooling is definitely necessary. This implies a standardization of the batteries, which should have prerequisites for liquid cooling.

8 Chapter 8 Recommendations This chapter gives proposals for further cooperation between China and Germany in the battery related electro mobility area, as 1. Regulations, Codes & Standards (RCS) 2. Energy Supply (Grid and Hardware) 3. Parameter and Safety Tests Harmonization 4. Battery Benchmarking 5. Battery Data Recording 6. Research & Development 7. Cooperation between Companies 8. Annual Chinese-German Meeting on Batteries 9. Joint Demonstration Programs These recommendations must be agreed by both parties. If both sides are deeply interested to go a mutual way for the EV development and deployment, these recommendations must be realized in whole or at least in a major part. Chapter 9 Appendix During the preparation of this study many literature were looked through and interviews were carried out. This way, a lot of information has been gathered. A part of this information, however, was too detailed and would go beyond the scope of this study whereas other parts would not directly meet its main topic. As this information is interesting anyway in the framework of this study, the following information is given in the appendix: - cell/battery test manuals - battery components (active masses, electrolyte, separator etc.) producers and products - detailed cell/battery data - actual battery news. We believe that this appendix is very valuable for people concerned in more detail with the battery subject in China and Germany. Because the volume of the presented information takes more than 250 pages, the appendix is to be found on the GCSFP-website

9 Table of Content 1 Introduction Requirements on propulsion batteries for cars Introduction Hybrid electric vehicles (HEVs) Micro Hybrid Mild Hybrid Full hybrid electric vehicles Plug-In Hybrid Electric Vehicles (PHEVs) Extended-Range Electric Vehicle (EREV) Fuel Cell Hybrids (FC-HEV and FC-PHEV) Battery Electric Vehicle (BEV) Battery Tests Introduction Test Procedures Parameter and Lifetime Tests Safety and Abuse Tests Evaluation Summary Battery development in China Introduction Chinese Battery Companies and Institutes Chinese Battery Products Summary Battery development in Germany Introduction German Battery Companies and Institutes German Battery Products Summary and comparison with China Battery development in other countries Introduction Battery producers Li-Ion Batteries Ni-MH batteries Advanced Lead-acid batteries Na-NiCl 2 high temperature battery (ZEBRA) Battery R&D institutions on Lithium batteries Products Lithium-ion batteries Ni-MH batteries Na-NiCl2 battery ( ZEBRA ) Lead-acid batteries... 64

10 6.5 State of the art HEV, PHEV, and BEV projects in other selected countries Company Information Co-operations Worldwide Lithium Resources and Lithium-Batterie Recycling Summary Energy supply for electric vehicles Introduction Energy demand for battery electric mobility CO 2 -emission reduction by electric mobility Grid buffering by BEVs Infrastructure for electric mobility Summary Recommendations Introduction Regulations, Codes & Standards (RCS) Energy supply Parameter and safety tests Battery benchmarking Battery data recording Research & Development Cooperation between companies Annual meeting on battery between China and Germany Joint Demonstration programs Appendix References... 84

11 Figures Figure 1: Structural transitions between different drive trains... 6 Figure 2: Power vs. time for the full hybrid function in NEDC for 1200-kg sedan Figure 3: Operating principle of PHEVs Figure 4: Battery SoC in different EREV operation modes Figure 5: Scheme of battery system Figure 6: Size of the Golbal Li-ion Battery Market, Figure 7: Size of the Chinese Li-ion Battery Market, Figure 8: Global Proven Lithium Reserves by Regions Figure 9: The influence of BEVs on the peak power and the daily power consumption in Germany; based on 10 kwh per battery and 3 kw chargers per vehicle Figure 10: Life time (Capacity turnover) of different battery types vs. Depth-of- Discharge, Figure 11: Ragone Diagram for different power sources... 77

12 Tables Table 1: Overview about described Chinese cells/batteries... 4 Table 2: Overview about described German cells/batteries... 4 Table 3: Overview about cells/batteries from countries beside China and Germany... 5 Table 4: Battery requirements for different electric cars... 7 Table 5: Overview on functionalities which define micro-, mild- and full hybrid... 9 Table 6: Assumptions of different US organizations for PHEVs Table 7: USABC goals for advance PHEV batteries Table 8: VDA specification for advanced PHEV batteries Table 9: USABC goals for advanced EV-batteries Table 10: Overview about performance HEV test conditions (HEV) Table 11: Overview about life-time test conditions Table 12: Overview about safety and abuse test conditions Table 13: Evaluation of safety tests based on the FreedomCAR/EUCAR hazard level Table 14: Chinese Li-Battery Companies Table 15: Chinese Nickel - metal hydride battery companies Table 16: Chinese advanced lead-acid battery companies Table 17: Overview on Chinese research organization in the battery field Table 18: Overview about Chinese Li-Ion batteries Table 19: Overview about Chinese Ni-MH batteries Table 20: Overview about Chinese advance lead-acid batteries Table 21: German Li-Battery Companies Table 22: German Ni-MH-Battery Compananies Table 23: German Advanced Lead-Acid Battery (LAB) Companies Table 24: Overview on German battery R&D organizations Table 25: Overview about German Li-Ion batteries Table 26: Overview about Continental Li-Ion battery development Table 27: Overview about German Ni-MH batteries Table 28: Overview (I) about German advanced lead-acid batteries Table 29: Overview on lithium-ion battery manufacturers in Korea Table 30: Overview on lithium-ion battery manufacturers in USA Table 31: Overview on lithium-ion battery manufacturers in Japan Table 32: Overview on lithium-ion battery manufacturers in Canada, France and Hong Kong Table 33: Overview on Ni-MH Battery Companies worldwide beside China and Germany Table 34: Overview on research organization in the field of lithium-ion battery research worldwide beside China and Germany Table 35: Overview about Li-Batteries worldwide beside China and Germany Table 36: Overview about Ni-MH batteries worldwide beside China and Germany Table 37: Data of Ni-MH cells for PHEV and HEV applications worldwide beside China and Germany Table 38: Product information for a ZEBRA (Na-NiCl2) battery by MES DEA

13 Table 39: Overview about advanced lead-acid batteries worldwide beside China and Germany Table 40: Overview on co-operations or joint development projects between automotive industry (incl. suppliers) and battery manufacturers Table 41: Overview about Energy demand in Germany and China for BEVs Table 42: Energy consumption and CO 2 emission of a compact class vehicle as ICEV and BEV Table 43: Well-to-Wheel CO 2 emission for a BEV with Li-ion Battery, NEDC... 72

14 Abbreviation list BATSO - Battery Safety Organization BEV - Battery electric vehicle BMS - Battery Management System BMBF - Bundesministerium für Bildung und Forschung (Federal Ministry of Education and Research, Germany) BMFT - Bundesministerium für Forschung und Technologie (now BMBF) (Federal Ministry of Research and Technology, Germany) BMU - Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Germany) BMVBS - Bundesministerium für Verkehr, Bau und Stadtentwicklung (Federal Ministry of Transport, Building and Urban Affairs, Germany) BMWI - Bundesministerium für Wirtschaft und Technologie (Federal Ministry of Economics and Technology, Germany) BTL - Biomass to Liquid CTL - Coal to Liquid DIN - Deutsches Institut für Normung e.v. (German Institute for Standardization, registered society) DKE - Deutsche Kommission Elektrotechnik, Elektronik und Informationstechnik im DIN und VDE (German Commission for Electrical Engineering, Electronics, and Information Technology in DIN and VDE) DM - Dual Mode (EV) DoD - Depth-of-Discharge, given in percent DoE - U.S. Department of Energy DST - Dynamic Stress Test EREV - Extended Range Electric Vehicle EV - Electric Vehicle, generic term for HEV, PHEV, EREV, and BEV sometimes only used for BEV EUCAR - European Council for Automotive R&D (formerly JRC) E85 - Ethanol Gasoline fuel mixture with 85% Ethanol FC - Fuel Cell FC-EV - Fuel Cell Electric Vehicle FC-HEV - Fuel Cell Hybrid Electric Vehicle FC-PHEV - Fuel Cell Plug-In Hybrid Electric Vehicle FUDS - Federal Urban Driving Schedule (or SFUDS) GTL - Gas to Liquid HE - High Energy HEV - Hybrid Electric Vehicle HP - High Power ICE - Internal Combustion Engine IEC - International Electro technical Commission ISO - International Organization for Standardization INEEL - Idaho National Engineering and Environmental Lab. JCS - Johnson Controls LAB - Lead-Acid Battery LEV - Light Electric Vehicles LIB - German Lithium-Ion Battery Program

15 MOST - Chinese Ministry of Science and Technology NEDC - New European Drive Cycle Ni-MH - Nickel Metal Hydrid Battery OEM - Original Equipment Manufacturer PDA - Personal Digital Assistant PHEV - Plug in Hybrid Electric Vehicle R&D - Research and Development RCS - Regulations, Codes & Standards RT - Room Temperature (23 ± 2 C) SAE - Society of Automotive Engineers SFUDS - Standard Federal Urban Driving Schedule (or FUDS) SLI - Start, Lighting, Ignition SNL - Sandia National Laboratories SoC - State of Charge SUBAT - Sustainable Batteries Three elements - Cathode Material for Li-Ion Batteries, which contains Nickel, Cobalt, and Manganese, each to 1/3 UL - Underwriter Laboratories Inc. UPS - Uninterrupted Power System USABC - United States Advanced Battery Consortium (DOE) VC - Venture Capital VDA - Verband der Automobilindustrie (German Automobile Industry Association) VDE - Verband der Elektrotechnik Elektronik Informationstechnik e.v. (German Association for Electrical Engineering, Electronics, and Information Technology, registered society) VRLA battery - Valve regulated lead-acid battery ZEV - Zero emission vehicle 863 program - Chinese high tech program (launched in March 1986; this date gave the program its name)

16 0 Preface This study is written in the framework of the German-Chinese Sustainable Fuel Partnership (GCSFP). Within the scope of the GCSFP Program, founded by the German Federal Ministry of Transport, Building and Urban Affairs (BMVBS) and the Chinese Central Ministry of Science and Technology (MOST) in December 2003, Germany and China have agreed to work together at a deeper level on questions of improving energy efficiency in road transport and the use of alternative and regenerative fuels. Besides BTL, CTL, GTL, and biodiesel also the electron has been considered as a sustainable fuel in the GCSFP program, which considers both fuel cell electric vehicles and battery electric vehicles. In a joint Chinese-German H2 & FC Workshop in Berlin on May 20th 25th, 2007 both sides presented their national R&D programs with the aim to identify main areas of potential mutual cooperation. Although the main focus of that workshop was H2 & FC, already at this time both sides were interested in cooperation in the field of the battery relevant electric vehicles as well. Later this interest for battery EVs expanded continuously and was highlighted with a Sino-German Electro mobility Workshop dedicated to battery EVs in Shanghai on 5 th December The battery is of main interest in the electro mobility area. To get an overview about the battery development in both countries it was decided to write a battery study. The aim of this study is to give information about the state-of-the-art of the battery development for EVs mainly in China and in Germany in order to provide a basis for cooperation. Furthermore it should be given a first overview about battery performance tests and abuse tests in order to see to what extent the battery data of both countries could be compared. This study will not give final solutions, but will show challenges and give recommendations for mutual projects in the area of traction batteries and the relevant infrastructure. Based on these recommendations detailed projects should be initiated.

17 Not all types of battery relevant cars as mild HEVs, PHEV need a Li-battery; therefore there is also given an overview about alternatives such as Ni-MH batteries and advanced lead-acid batteries. The battery information presented in this study is mainly based on literature studies, conference materials, internet search, and company inquiries. Unfortunately not all, especially German companies have given information about their products. The available battery information was often very different from the given data. Beginning with information only about the voltage and capacity of the battery and ending with very detailed description about temperature and load dependencies of different electrical parameters. To have a possibility of better comparison a standard table was created with the most important data of the battery as voltage, capacity, energy and power values, dimensions, mass etc. Additional detailed data if available are to be found in the appendix. Another point is that many companies have besides their standard products also special customer-designed products for which normally no information is available. Nevertheless the authors believe that their study represents the current state-of the art in the traction battery area, i.e. even if not all battery data are available in detail, it is not expected, that a market near new battery is missing in this study. Besides the battery relevant data, also an overview about battery components (active masses, electrolyte, separator etc.) is given. Because the battery components are not in the centre of this study a short overview is given in the appendix as well. Contrary to battery information, nearly all test procedures for performance tests and abuse tests were available with the exception of the EUCAR test procedures.

18 Values of CO 2 emissions and fuel/energy consumption are dependent on different factors as the car weight, the driving profile etc. Therefore these values are given in the literature in a broader band. The energy consumptions for EVs e.g. vary between 10 kwh/100 km and 20 kwh/100 km. As far as possible the conditions for the values are given. Covered in the study are passenger cars. If detailed data are given e.g. in relation to fuel consumption or CO 2 emissions the type of car or the driving behaviour are described. For Figures and Tables taken from the literature the sources are given. All Figures and tables without references are self drawn. Finally it is to mention that this battery topic is very dynamic. Nearly every week new information in the battery area is given. Some of that information is given in the appendix as well. The study was written by the following team: - Prof. Dr. habil. Jürgen GARCHE, Fuel Cell and Battery Consulting (FCBAT) ( garche@fcbat.eu, phone&fax: Dr. Bernhard RIEGEL, Hoppecke Batterien GmbH & Co KG. ( bernhard.riegel@hoppecke.com, phone Prof. Dr. Dirk Uwe SAUER, Institute for Power Electronics and Electrical Drives - ISEA of RWTH Aachen ( sr@isea.rwth-aachen.de, phone: Dr. XIAO Chengwei, China Electronics Technology Group Co. No. 18th Research Institute, Tianjin, cwxiao@yahoo.com, phone:

19 1 Introduction The battery market is older than 100 years and the world-wide battery sales in 2004 was US $ 31.8 bill. Half of these sales belong to the lead-acid battery for starting application (SLI) in cars. But in the last years besides the traditional applications (SLI, industrial, consumer) new drivers exist for the battery development. These are applications of batteries in electric cars (hybrids, plug-in hybrids and battery EVs) and in storage of renewable energies. Germany Germany has a long tradition in battery development and production, especially related to electric vehicles. The development concerns the conventional lead-acid battery (LAB) as well as the Ni-Cd batteries and also advanced batteries such as the Ni-MH battery (VARTA, DAUG, Hoppecke) and the Na-high temperature battery (ABB, AAB). During the 20 years after the oil crisis (1973) e.g. Volkswagen developed 300 EVs and Daimler-Benz 250 EVs. This development was further accelerated by the California Air Resources Board (CARB), which passed a Zero Emission Vehicle (ZEV) Program in This program laid down that 2 % of the total car fleet by 1998 and 10 % by 2003 must be EVs. As one consequence of the ZEV program in Germany, the German Federal Ministry of Research and Technology (BMFT) initiated a project called Rügen- Project concerning in total 60 EVs from different manufacturers and different types. Also different battery technologies (Pb, Ni-Cd, Ni-MH, Na-S, Na-NiCl 2,) were involved. This project covered the period between1992 and One result of this project was the fact, that efficiencies and CO 2 emissions (based on the mix of German electric power stations) between BEVs and ICE cars don t differ considerably. These disappointing results, besides the limited range of the BEV, led to a change of the electro mobility orientation towards fuel cell EVs in Germany. 1

20 This was practical the end of the German government support for battery and BEV development for a longer time. Battery research was done mainly in the field of offgrid power supply systems based on renewables and therefore at least some exercise survived. Furthermore in this time many German battery companies were sold to foreign companies, as e.g. Sonnenschein, Hagen, Deta Exide (USA), VARTA parts to Hawker (USA), parts to Johnson Controls (USA), and parts of Hoppecke Johnson Controls (USA). This led to a further reduction of the battery R&D in Germany. This situation was aggravated by the fact that the consumer equipment production (cellular phone, camcorder, computer etc.) moved to Far East and therefore the consumer battery R&D and production were strongly reduced in Germany. Despite the finished government support, some start-up company s started in the end of the nineties the development of Li batteries, as e.g. GAIA, Li-Tec and Fortu. For a better efficiency and reduced CO 2 emissions, the German car manufacturers invest mainly in diesel cars instead in EVs. Billions of Euros were spent also for the development of fuel cell vehicles. As an alternative to diesel cars in Far East and USA, hybrid cars have been developed. Since about 3-4 years hybrid electric vehicles are also seen in Germany as an option for the reduction of CO 2 emissions; since at least partial full electric driving is also possible with plug-in hybrid electric vehicles (PHEV), these latter are considered as something desirable. This led to a revival of the battery development in Germany, which is supported also by the option of renewable energy storage. Based on this paradigm change, the German Federal Ministry of Education and Research (BMBF) started a Lithium-Ion Battery program (LIB 2015) with 74 Mio. EUR support and additional 360 Mio. EUR from the industry. The Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) supports a 4-year plug-in vehicle fleet project with 25 Li-Ion battery based cars with 15 Mill. EUR. This project was started by Volkswagen and the energy supplier E.ON in

21 As a part of the German Integrated Energy and Climate Protection Program, agreed on 23rd/24th August 2007 in Meseberg ( Meseberg Program ), a National Innovation Program Electric Mobility has been developed by the Federal Ministry of Transport, Building and Urban Affairs (BMVBS), the Federal Ministry of Economics and Technology (BMWi), the BMBF, and BMU. The national government is aiming for one million electric vehicles until The detailed support measures will be presented at the end of this year. In the framework of the German economy stimulation package II to fight the economic crisis there will be about 500 Mio. EUR spent in the next three years for electro mobility and a large part of that for battery R&D. China Following the Chinese opening-up policy and continuously rapid economic growth, China has seen a vast progress during the past 20 years concerning battery technology and production for lead-acid, nickel metal hydride, and lithium ion batteries. Twenty years ago, in the field of lead-acid battery, manufacturing processes and production equipment have had a low standard with manual operation and no automation. The demand for lead-acid battery grew steadily with the development of some national key sectors like automotive, communication, power and railway, especially in recent year s e-bike and photovoltaic systems. Lead-acid battery technology has changed greatly in the last 20 years. In the 1980s only ordinary flooded SLI batteries were built. But since the 1990 more and more valve regulated lead-acid batteries (VRLA) are produced. The number of lead-acid battery manufacturers in China is estimated to over 1000, and some foreign lead-acid battery enterprises began to set up factories and make investment in China; therefore, China became a lead-acid battery production base for the world. 3

22 In the field of nickel-metal hydride battery, China began to explore the possibility of using hydrogen absorbing alloys as electrode materials in 1970s, and became the third country to make nickel-metal hydride battery production industrialized after the USA and Japan. In the mid-1990s, some enterprises began to introduce abroad and develop independently a number of nickel metal-hydride battery production lines, which helped greatly to improve the technology and make mass production possible. Manufacturers are mainly located in Guangdong, Zhejiang, Shanghai and Tianjin and produce about million cells per year. The products are mainly applied in electric tools, electric toys, and communication devices for the national market as well as for export. In the field of lithium-ion battery, the 1980s saw the start of lithium ion battery research, and the first commercial lithium-ion battery was introduced by Sony (Japan) in Some institutions in China almost simultaneously conducted the research on lithium-ion battery. Since 2000, a large scale production has been established in China featuring mature technology, automation and lower cost, leading to an ever-increasing international market share. Regardless of the competition from Japan and Korea, China s market share has exceeded 50% in 2008, with major lines of small storage cell applied in mobile phone, laptop computer, PDA, digital camera, etc. China has been involved in power battery technology development and research since the 9 th five-year plan ( ) with funding from the hi-tech plan (also called 863 plan) of the Ministry of Science and Technology (MOST). In the 9 th five-year plan, the power battery R&D included lead-acid battery, nickel-metal hydride battery and lithium ion-battery. In the 10 th five-year plan, the fund flew to nickel metal hydride battery, lithium ion battery and some pilot product lines were established. In the 11 th five-year plan, lithium-ion battery chemistry, including lithium-iron phosphate and lithium-manganese spinel, are in the focus of the funding by MOST for research on high power and high energy, and is expected to reach 100,000 units production capacity for HEV, PHEV, and BEV by the end of

23 Meanwhile, in other national science and technology programs, lithium ion batteries and relevant materials are privileged technologies. Presently power battery chemistry in China develops drastically, leading to vast investment in industrial production by some enterprises for electric tools, electric bikes, electric vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, etc. Through national policy guidance and incentives, the power battery technology chemistry has made great achievements with regards to safety, specific power, specific energy and cycle life. Several demonstration vehicles were put into operation. More than 500 electricity-driven vehicles were operated during the Beijing Olympic Games, and the results were successful. Both countries Whereas for HEVs the Ni-MH battery and for Micro-HEVs also the advanced leadacid battery could be used, for PHEVs and BEVs the Li-ion battery is the system of choice, caused by its higher specific energy. The main cathode materials at present are cathode materials with lower cobalt content, as three elements material (Ni 0.3 Co 0.3 Mn 0.3 ), lithium-iron phosphate and lithium-manganese spinels. As anode material mainly graphite and more recently also lithium-titanates are used. The most important battery parameters at the moment are safety and costs. The safety issue will be especially at higher temperatures a problem. By use of lithiumiron phosphate and lithium-titanates the risk is reduced. The costs are at present in Germany in the region of 1,000 /kwh for the battery, in China about 1/3 lower. For the next generation of batteries intensive research in both countries is ongoing for lithium-sulphur, lithium-air and magnesium systems. 5

24 2 Requirements on propulsion batteries for cars 2.1 Introduction There are many different types of vehicles using batteries for propulsion, aiming at different goals - to reduce the fuel consumption and CO 2 emission as much as possible while maintaining the driving performance and comfort - to improve the driving performance while maintaining the fuel consumption The most significant distinction between different hybrids is the degree of hybridisation between the ICE and the electric motor (EM) reaching from the pure conventional ICE drive train to purely electric systems as is shown in the following picture: Figure 1: Structural transitions between different drive trains 1 (ICE-Internal combustion engine, G- Generator, EM Electric Motor, S-Storage Unit, GB-Gear box, D-Differential) This picture gives a general overview. In detail, however, there are also other variants besides the parallel and series hybrid, as e.g. the power-split hybrid or series-parallel hybrid, which belongs to parallel hybrids. They incorporate power-split devices allowing for power paths from the engine to the wheels that can be either mechanical or electrical. 6

25 Reflecting this Figure one has to consider the following types of vehicles: - Hybrid electric vehicle (HEV) - Micro HEV - Mild HEV - Full HEV - Plug-in hybrid electric vehicle (PHEV) - Fuel Cell hybrid electric vehicle (FC-HEV) - Battery electric vehicle (BEV) An overview on the battery demand for the different types of electric vehicles is shown in the following table. Table 4: Battery requirements for different electric cars Vehicle concept Micro Hybrid Mild Hybrid Full Hybrid Plug-In Hybrid Full Electric Vehicle Short description stop/start, limited reg. braking with starter generator, no electric driving stop/start, reg. braking acceleration boost, no electric driving stop/start, reg. braking acceleration boost, short electric driving stop/start, reg. braking, full electric driving reg. braking, full electric driving Typical voltage 12 V V V V V Energy capacity kwh 1 kwh 1 kwh 5-10 kwh kwh 0.6 kwh + 50 Power 2 kw 5-20 k-w kw kw kw lead-acid Lead-acid, NiMH, Li-ion (HE/HP), Li-ion (HE) Technologies Lead-acid & Supercaps NiMH, Li-ion (HP) maybe Lead-acid and maybe NaNiCI2 Li-ion (HP) NaNiCI2 Cycle regime Lifetime Power & energy typical 60-80% SOC, cycle depth during stop mode 1% typical 40-60% SOC typical 40-60% SOC, typical % SOC typical % SOC micro cycle micro cycle micro cycle depth 2% depth 5% depth 1% several 100,000 several 100,000 several 100,000 3,000 full cycles plus 3,000 full cycles micro cycles, microcycles microcycles several 100,000 5 years for lead-acid battery microcycles 5-10 kw for cranking, 5-20 kw/kwh kw/kwh 5-20 kw/kwh 3-5 kw/kwh kw for normal operation 1-3 kw/kg > 100 Wh/kg > 150 Wh/kg Fuel Cell Vehicle from battery point of view essentially a full hybrid or in future a plug-in hybrid These values give a first overview about the battery demand even though they can deviate a little bit from the given values. 7

26 2.2 Hybrid electric vehicles (HEVs) Even after decades of development for road vehicles there is no clear-cut definition of hybrid powertrains. The classification of hybrids is somewhat arbitrary and the limits between the various types are floating. Figure 1 distinguishes parallel and series hybrid configurations. In parallel hybrid electric vehicles the combustion engine is the primary source for driving the vehicle forward. Electric motor(s) is (are) added to provide additional power during phases where combustion engines have poor efficiency. The battery is maintained at nearly constant SoC using energy from the combustion engine and kinetic energy during deceleration and braking. In series hybrids the power provided by the ICE is converted by 100% into electricity, which is used to propel the vehicle or is stored in the battery. The EV with range extender is a typical series hybrid. The fuel cell electric vehicle is in fact also a series hybrid. This degree of hybridization depends on the demanded functionality of the car and gives also the name for the hybridization mode. The following table gives an overview about the most important functionalities. 8

27 Table 5: Overview on functionalities which define micro-, mild- and full hybrid Mode Micro Hybrid Mild Hybrid Full Hybrid Improved Generator Cold Cranking Stop - Start Boosting Regeneration Electric driving : full used, +: partially used, 0: not used Hybridization offers a number of improvements for fuel cell electric vehicles (FC). Efficiency is enhanced by storing the energy from regenerative braking, which is not possible with the FC alone. Furthermore the battery helps to avoid working regions of poor efficiency as in the case of ICE-HEVs. Therefore, the energy and power requirements do not differ greatly between the ICE- and FC HEVs. The energy for start-up of the FC and moderate driving performance is easily provided by this type of battery, although at the cost of a somewhat higher depth of discharge (DoD) Micro Hybrid The stop-start function marks the low end of hybridization. Electric propulsion is limited to a velocity of the vehicle corresponding to an enhanced idle rotation speed of the ICE of revolutions per minute (rpm) on start. Besides the support of the start phase, where the car starts in an electric mode while the ICE is only being started, one further main task for the battery is the supply of the power demand during the stop phases while the ICE is shut down. During the stop phase between 400 W and 1500 W must be delivered depending on the auxiliaries and the ambient conditions. 9

28 This leads to significant energy throughputs during the stop phases: 1000 W e.g. will produce 1000 kwh of energy throughput within 4 years and 50,000 km of driving. Depending on the type of starter-generator used, there is substantial potential to regain energy by regenerative braking. The requirements for the battery (preferred 42 V battery) for the start-stop application including power demand during the stop phases are as follows: calendar life power on stop cold cranking power energy throughput during 50,000 km 4 years; W 6 kw, 15s at 25 C 1,000 kwh Besides that described Micro Hybrid Applications, which are called sometimes also Soft Stop and Go Hybrids, there are also Hybrids which are called Stop/Start Hybrids. Here the starter-alternator is only used to start the ICE and regenerative braking is done via the starter alternator (approx. 2 to 3 kw max.). Power required is in the order of 2.5 kw. Huge activities are ongoing to improve 12 V lead-acid batteries to cope with these requirements. Forecasts for the European automotive industry show a steady increase of the Stop/Start Hybrids and maybe in 2015 already all conventional cars are equipped with this type of hybridization. The fuel saving is in the range of 4 to 6% Mild Hybrid The changes in the drive train are larger than in the micro hybrids. An electric motor is inserted in the drive axle and after cranking the car can stay in the EV mode up to a speed of km/h before the ICE starts. This also requires a transformation of all auxiliaries to electric operation instead of mechanical drives (e.g. braking or steering support, climatization). 10

29 In mild-hybrid electric vehicles acceleration of the vehicle is supported by the electric drive with substantial power. Notably, from these power requirements currents of approximately 500 A can result. This, in turn, represents approximately the reasonable limits of the 42-V power net. On the other hand, this allows most of the regenerative braking energy offered during the NEDC to be utilized. The battery requirements for mild hybrids derived from the propulsion system perspective are as follows: Voltage 36V Peak Power 15 kw for 18 s Power, -25 C 6 kw for 15 s Energy 1 kwh Weight < 20 kg Cycle life > cycles (with ± 3% DoD (depth-of-discharge) cycles) Calendar life 15 years Full hybrid electric vehicles Today the majority of the commercial full hybrid electric vehicles are based on the parallel or split-hybrid configuration. A limited range of a few kilometers in pure EV mode is possible. The battery energy is still small (1-2 kwh) but the power is in the region of kw. Therefore the specific power of the battery must be very high. The state of charge of the battery has to be maintained at an intermediate level to deliver peak power to the driving train and to accept charge power from the regenerative braking or the engine. The SoC swing during normal operation is typically less than 50 Wh. Sometimes the Full Hybrid is called also Power Assist Hybrid. Naturally the full hybrid is best suited to shift the electrical power via the battery to where it can be used most efficiently or effectively. Figure 2 shows the simulation results of a 1200-kg sedan while performing the NEDC. 11

30 Figure 2: Power vs. time for the full hybrid function in NEDC for 1200-kg sedan 2 In this case, the required battery data are as follows: Voltage Peak Power Power, -25 C Energy Weight Cycle life Calendar life ca. 300 V 40 kw for 18 s 6 kw for 15 s 1 to 2 kwh < 50 kg > , ± 3 DoD 15 years 2.3 Plug-In Hybrid Electric Vehicles (PHEVs) Plug-in hybrids are hybrids offering the possibility of charging the battery from the electric grid. The vehicle can run in pure electric mode, as long as energy from the battery is available. Typical pure electric driving ranges are between 15 and 60 km. After the pure electric drive mode the vehicle can continue in the HEV mode, where the battery will be remain more or less in the same DoD, as the following Figure shows: 12

31 SOC / % Charge Depletion- CD (EV mode) Charge Sustaining CS (HEV mode) range / km Figure 3: Operating principle of PHEVs The PHEV architecture is mainly equivalent to a full HEV. Only the battery size is larger to allow for extended electric driving range. The PHEVs are classified into groups related to this maximal electric mode driving range. These groups are called: PHEVXX, i.e. means a PHEV with a maximal electrical driving range of XX miles, e.g. PHEV40 means the electrical driving range amounted to 40 miles or about 60 km. There are different assumption for the number of XX and therefore for the battery performance (see the following Table). Table 6: Assumptions of different US organizations for PHEVs 3 Units USABC 1 MIT 2 EPRI 3 Vehicle Assumptions CD Range Miles CD Operation - All electric All electric Blended All electric All electric Body Type - Cross SUV Mid Car Mid Car Mid Car Mid Car Total Battery Mass kg Total Vehicle Mass kg Battery "Goals" Peak Power kw Energy Capacity kwh Calendar Life years CD Cycle Life cycles 5,000 5,000 2,500 2,400 1,400 CS Cycle Life cycles 300, , ,000 < 200,000 < 200,000 CD: Charge depletion, CS: Charge sustaining 13

32 More specified USABC goals are shown in the following Table. Table 7: USABC goals for advance PHEV batteries 4 Units PHEV-10 (High Power to Energy Ratio) PHEV-40 (Low Power to Energy Ratio) 1) Basic Assumptions Body Type Crossover SUV Midsize Car All Electric Range miles Max. System Mass kg Max. System Volume L ) Power Peak Power (2 sec./ 10 sec. Pulse) kw 50 / / 38 Spec. Density (2 sec./ 10 sec. Pulse) W/kg 830 / / 320 3) Energy Capacity Available Energy kwh 4 12 Total Energy (@ 70% DOD) kwh 6 17 Total Spec. Energy Wh/kg ) Life Calendar Life years Deep Dischargw Cycles (CD Mode) cycles 5,000 5,000 Shallow Dicharge Cycles (CS Mode) cycles 300, ,000 Temperature Range C -46 to to +66 5) Safety Abuse Tests - Acceptable Acceptable Germany follows closely the USABC goals, i.e. the maximal electric driving range is in the order of 15 and 60 km. For the German VDA test conditions see the following table. 14

33 Table 8: VDA specification for advanced PHEV batteries 4 Parameter Unit high power to energy ratio low power to energy ratio Discharge pulse power (10 sec) kw Regenerative braking charge pulse power (10 s) kw 20 (55 Wh pulse) 35 (97 Wh pulse) Available energy (capacity range in which the kwh 0.3 (@ 1C rate) 0.5 (@ 1C rate) required power performance is available) Minimum round-trip efficiency % 90 (25 Wh cycle) 90 (50 Wh cycle) Cold cranking -30 C (three times 2 sec with 10 sec pause in between) kw 5 7 Cycle lifetime in specified SoC range Cycles 300, Wh cycle (7.5 MWh) 300, Wh cycle (7.5 MWh) Lifetime Years > Maximum weight kg Maximum volume l Operating voltage V DC max. 400 V min > 0.55 V max max. < 400 V min > 0.55 V max Max. self discharge rate Wh/d Temperature range - operation temperature - storage temperature Production cost (per piece at 1 million units per year) C -30 to to to to +66 US$ PHEVs require larger battery packs (see Table 6) plus a normally on-board charging interface (about 3 kw), thus increasing the cost of the overall hybrid system considerably. The SoC swing of the battery is much higher than in normal hybrid mode. It is expected that this will affect battery life negatively. The battery cycle life should be 10 years. It is to consider also that the power of the battery is normally going down with the SoC. Therefore at the end of the pure electrical driving the battery is strongly stressed. 2.4 Extended-Range Electric Vehicle (EREV) Whereas the PHEV described in chapter 2.3 is a parallel hybrid (both an ICE and an electric motor are connected in parallel to a mechanical transmission), the EREV is a series hybrid (the ICE drives an electric generator, which both charges a battery and powers the electric motor). From the effiency point of view it is to prefer that the battery is charged in the parking time by the grid, though the charge by the ICE, however, with low efficiency is possible as well. 15