Electric Vehicles and Their Batteries Development in China

Prof. Feiyu KangDept. of Materials Sci. & Eng.Tsinghua University, China

17th November, 2009

Outline

• The development trends of electric vehicles

• Fuel cell electric vehicle (FCEV)• Hybrid electric vehicle (HEV)• Purely battery-powered electric vehicle

(BEV)– Lithium iron battery (LIB)– Super-capacitor (EDLC)

• Future development trends (LIB+EDLC)

Electric Vehicles

Classification of EV

• Electric vehicles (EVs): fuel replaced with electricity, combustion engine replaced with electric motors.

• EVs are classified into three categories: – Purely battery-powered electric vehicles, BEV; – Hybrid electric vehicles, HEV and plug-in hybrid elect

ric vehicles, PHEV ；– Fuel cell electric vehicles, FCEV

EV MarketEurope: electric vans China: buses

USA: cars India: mini cars

USA strongly develops LIB cars• On 7th Jan. 2009, A123 Systems of the US announced the

plan to build the first LIB factory in Southeast of Michigan in order to help the US economy get rid of the dependency on petroleum. After that several factories will be built in the US to meet the battery demands for 5 million hybrids and 500,000 Plug-in hybrids by the end of 2013.

• A123 Systems will invest 2,3 billion US dollars in the new factory and apply a loan of 1.84 billion dollars from the stimulation program named ATVMIP with a total sum of loan for 25 billion dollars for high-tech cars operated by the Energy Ministry of US.

• Before that LIB manufacturer EnerDel has also applied 480,000 dollars of low-interest load from the Ministry of Energy. The manufacturing capacity of LIB will reach 600,000 battery bags by 2011 and 1.2 million by 2015.

Ministry of Finance,Ministry of Science and Technology

“Announcement about promoting pilot cities of energy saving and new energy cars”

• Programs of energy saving and new energy cars have been implemented and promoted in 13 cities in China, such as Beijing, Shanghai, Chongqing, Changchun, Dalian, Hangzhou, Jinan, Wuhan, Shenzhen, Hefei, Changsha, Kunming and Nanchang. The program gives financial support to encourage energy saving and new energy cars in public transportation, taxes, public service, environment and hygiene and postal services.

• Hybrid cars and light business cars must save energy for over 5% and hybrid buses should save energy for over 10%.

• Battery manufacturers must provide a quality guarantee of over 3 years or 150 thousand km.

Financial surpport for public and business vehicles (x10,000 Yuan)

Energy saving and new energy

vehicles

Fuel saving rate

Highest power rate

BSG type 10-20% 20-30% 30-100%

Hybrid 5-10% 0.4 -- -- --

10-20% 2.8 3.2 --

20-30% -- 3.2 3.6 4.2

30-40% -- -- 4.2 4.5

over 40% -- -- -- 5.0

BEV 100% -- -- -- 6.0

FCEV 100% -- -- -- 25.0

“Ten cities thousand cars” –program to promote EVs

• The aim of the program is to test 1000 new energy cars in 10 cities within the next 3 years, in order to promote the scale and commercialization of new energy cars. The national goal of new energy cars is to reach 10,000 cars by 2010 and EV will take up 10% of market share by 2012.

2 national projects of priority

• “Energy saving and new energy cars” and “High technology of cars” are the two important national projects with a focus on research and commercialization of new energy cars and LIBs.

Government approved 10 types new energy cars

• BYD ： F3DM, F6DM and E6• Huachen: 华晨尊驰混合动力• Changan: 长安杰勋混合动力• Cherry: 奇瑞 A516 混合动力• Yiqi: 一汽奔腾混合动力；• Joint ventures:• SAIC-Volkswagen: 上海大众途安混合动力车和领驭电动车• SAIC-GM: 上海通用君越混合动力。

Bottlenecks and Priority

• Advanced batteries, motors and control system are bottlenecks. – LIB, improve the energy and power densities,

cycle life (target: 2000 recently, 5000 in future), reliability, and quick charge, low cost.

– Driving motor, using permanent magnet, improve power, power density, efficiency, life and reliability, low cost.

• Priority:– Buses, low-speed cars and special vehicles

Fuel Cell Electric Vehicles

Proton Exchange Membrane Fuel Cell, PEMFC

Advantages of PEMFC

• Not limited by Carnot cycle• High energy conversion• Quick start in room temperature and no

loss of electrolyte• Easy water emission and long life• High power and energy rate• Suitable for mobile power and ideal power

for EV

Fuel Cell City BusTsinghua University and Shenli Science Technology Company Tsinghua University and Shenli Science Technology Company

Tsinghua University project group provided 5 fuel cell buses for the 2008 Olympic games.

Fuel Cell Vehicles Tongji University & Shangqi

Properties: Power ： 24KW

FCE Power ： 30KW

Battery stack ： 30AH

Peak Speed ： 108.3 km/h

Gradient ： > 20°

Acceleration ： 14.9s(0-80km)

Range ： 209 km

Economy ： .394kgH2/100kmTongji University project group provided 20 fuel cell Passats for the Olympic games.

Hydrogen Station in Beijing

Practical Difficulties of Hydrogen Energy

• The popularization of hydrogen depends on the production, storage and transportation of hydrogen.

• At present, the costs of producing hydrogen are too high and no good methods have been invented to store and transport hydrogen.

• Storing hydrogen by metal hydride suffers from low hydrogen rate and storing by pressure tank consumes too high energy.

Production of H2 ：• Hot methods: steam restructuring,

heat chemical hydrolysis, vaporization and high temperature pyrolysis

• Electro-chemical methods: electrolysis, photo-electrolysis

• Biological methods: photo-biological, microbial fermentation

Storage and Transportation of H2 ：• Gas: Carbon fiber composite mate

rial tank• Liquid: ultra low temperature insul

ation vacuum flask• Solid: Metal hydride

Fuel cells need nano-technology

• Catalyst– Metal– Support

• Hydrogen– Producing– Storage

Hybrid electric vehicles, HEV and plug-in hybrid electric vehicles ， PHEV

BYD’s F3DM hybrid electric car

The car came to the market on 15th Dec. 2008 and the price is 150,000 yuan.

Purely battery-powered electric vehicles, EV

Lithium Ion Battery

Advantages of BEV

• BEV is highly efficient, independent of fuel and has zero emission. It has become the most competitive technology.

• BEV takes advantage of cheap off-peak electricity during the night. In 2007 electricity capacity of China exceeds 700 million KW and off-peak capacity is 920 million KW, which can charge 40 million LIB cars.

• In Chen Liquan’s article “Developing LIB cars is the strategic choice of financial crisis”, LIB cars can replace petroleum with electricity, reduce CO2 emission and store off-peak electricity.

Electric bus for the Olympic games

• Developed by Beijing University of Technology

• Represented by bus line No. 121

• Change batteries in 10 min.

Secondary batteries• Secondary batteries can be charged repeatedly.

They are also called rechargeable batteries. It is convertible direct power. Charging process is to convert electric power into chemical power and releasing process is to convert chemical power into electricity.

• Lead acid battery （ high usage ）• Nickel secondary battery （ Nickel-cadmium, nic

kel-metal battery ）• Lithium ion secondary battery

The characteristics of lead acid battery

Cathode ： PbO2

Anode ： PbElectrolyte ： H2SO4

• Low energy density and efficiency

• Pollution

Ni-H battery • Cathode ： Nickel

• High density sphere Ni(OH)2

• Ni(OH)2

-Ni(OH)2

• Nano-size controlled?

• Ni-H batteries’ energy density is high. Theoretically density of Ni-H is 1.5-2 times higher than Ni-Cd batteries.

• Ni-H battery is more environmental friendly. It does not use cadmium, nor poisonous elements.

• Ni-H battery basically removes the “memory effects”.

Lithium Ion Battery

High power pressure ，about 3.6V ；

High energy density, about 150Wh/kg ；

Environmental friendly, does not contain lead, cadmium or other harmful elements ；

Low energy releasing ； No memory effects

The charge and discharge mechanism of lithium ion battery

Cathode Materials

• LiNi1/3Co1/3Mn1/3O2

• LiMn2O4

• LiFePO4

• Li-V-O compound• 5V cathode material• Multiple anion cathode materials• Other cathode materials

Anode Materials-Carbon Natural graphite300 － 350mAh/g Oxidation

High regul. Modifications Fluorination

Synthesis, mainly MCMB Coating

300 － 330mAh/g Film

Coke 200 － 230 mAh/g

Carbon Low regul. Needle coke 220 － 250 mAh/g

Pitch coke 200 － 230 mAh/g

Phenolic resin 400 － 500 mAh/g

Non regul. Polymer 400 mAh/g

(Amorphous) Pyrolytic carbon 500 － 900 mAh/g

Anode Material-

• Li4Ti5O12 (LTO), nano-particles • Was usually synthesized by solid state rea

ction using Li2CO3 and TiO2. • Very long life cycles (more than 10,000).

ATL- Polymer LIB

Capacity ： From 10 mAh to 10 AhSize ： From 10x20 mm to 70x200 mm

HEATING PAD

BATTERY TRAY

Battery Cable (50 Sq. mm, Flat)

50V/200Ah

Mini Electric Car

Electric Truck

• Mail delivery car

EVs• Buses

– Power requirement• 390V/360Ah

– ATL solution• Module 3.2V/180Ah • Pack: 122S2P

• Water spraying vehicles– Power requirement

• 380V/400Ah– ATL solution

• Module: 3.2V/200Ah • Pack: 120S2P

• Garbage compressed vehicles– Power requirement

• 336V/200Ah– ATL solution

• Module: 3.2V/200Ah • Pack: 104S1P

Battery & Modulus

Electrical core ModulesDimension:5.9*162*255mm Dimension:71*170*285mmEnergy: 3.2V/20Ah Energy: 3.2V/200Ah

10ea cell in parallel

Purely battery-powered electric vehicles, BEV

Supercapacitor

SupercapacitorsNissan’s capacitor for Nissan’s capacitor for hybrid EV 2002hybrid EV 2002

Japanese super capacitor hybrid buses 2002

Sizuki’s100 kW UPS

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EDLC Working principles

Comparison between capacitors, super capacitors and batteries

Capacitor Supercapacitor Battery

Discharge Time 10-6-10-3 sec 1-30 sec 0.3-3 hours

Charge Time 10-6-10-3 sec 1-30 sec 1-5 hours

Energy Density （ Wh/kg ） < 0.1 1-10 20-100

Power density （ W/kg ） > 10,000 1000-2000 50-200

Efficiency About 1.0 0.90-0.95 0.70-0.85

Cycle Life Unlimited > 100,000 500-2000

Super capacitor has the advantages of capacitors and batteries and complements the two traditional technologies. It aims for high power and

energy density.

Supercapacitor

0 100 200 300 400 500 600

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.2A

4.5A2A

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Vol

tage

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Discharge time (s)

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0 2 4 6 80

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tage

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Energy density / (Wh/Kg)

a (2.8V/100F) 100W/Kg 200W/Kg 500W/Kg 1000W/Kg

Aowei’s Ultracap Bus

Supercapacitor buses produced by Shanghai Aowei

• Vehicle Size:37 Feet 6 Inches Length ； 8 Feet 2 Inches Width ； 11 Feet 1 Inch Height ； 41 Passengers

• Maximum Speed: 30 MPH• Power Source: 5.9 KWH • Ultracapacitors Electric Usage: 1.5 KWH per Mile • Recharging Time: 5-10 Min.• Maximum Range: 3.5 Miles with full air conditioning; 5.5 Miles witho

ut air conditioning • Bus Weight: 12.5 Tons• Acceleration: 4 Feet / S• Maximum Slope:  12 Degrees• Voltage & Current: 600-720V, 200A • Air Conditioning: 15 KW • Vehicle Life: 8-12 Years

Other supercapacitor vehicles produced by Aowei

Properties of hybrid buses produced by Harbin Jurong Co.

• Motor power 20 ～ 30KW• Fuel capacity 100L• Super capacitor capacity 3KW

h• Max. power of super capacitor

120KW• Capacitor pressure 600V• Max. 41 seats• Total mass 17,000kg• Max. speed>50km/h• Starting acceleration >1.2m/s2• Kinetic energy saving and recy

cling• Max. slope degree >12%• Electric air conditioner 9KW

Future Trends forPurely battery-powered

electric vehicles

Lithium Ion Battery + Supercapacitor

Bottleneck of LIB EV’s commercialization

• In order to commercialize LIB EVs, 3 key problems must be solved:– Expensive battery, 80,000 Yuan, which

accounts for over half of the costs of the car– Limited driving distance per charge, less than

200 kilometers and thus battery capacity needs to be improved

– The safety of BEV battery has always been a challenging problem for the researchers.

Potential Solution

• Safety ：• Cathode materials ：

LiFePO4

• Small-sized batteries design

• Hybrid battery system LIB+EDLC

• Lower cost ：• LiNi1/3Co1/3Mn1/3O2

• LiMn2O4

Hybrid System: LIB+EDLC• Combining LIB and EDLC. EDLC has the advantages

of quick charge, no memory discharge, high recycling times and no pollution, but the weaknesses include quick electricity discharge and low energy density. LIB has the advantages of high electricity capacity and long storage time, but the charging time is long. Hybrid EDLC combines the advantages of the two technologies.

• Replacing fuel by electricity and zero emission are the main advantages. Hybrid EDLC EV drives long distance per charge (reaches 300 kilometers) and has high speed (100-120 km per hour) and high energy recycling efficiency.

Comparison of energy and power stored

Future study for LIB+EDLC EVs

• Polymer LIB• High efficiency• Safety• Quick charge and

discharge

• Supercapacitor• Improve energy

density• Improve voltage

range

Charge storage mechanism• Bivalent cation charging to improve capacitance

Univalent cation charging

univalent cation

Bivalent cation charging

bivalent cation

α-MnO2

Mn4+ Mn3+ Mn4+ + e- ↔ Mn3+

2Mn4+ + 2e- ↔ 2Mn3+

Charge storage mechanism• Comparison of Na+, Ca2+,and Al3+ .

Na: 194 F/g

Ca: 310 F/g

Al: 40 F/g

CVs of MnO2 at 2 mV/s

Asymmetric supercapacitor

△EAC △EMnO2

The schematic working voltage of asymmetric capacitor

Negative CAC: 80 F/g

Positive CMnO2: 310 F/g

Current collector

Mass ratio ： 1:4

Coin cell:

Electrolyte: 0.1 mol L-1 Ca(NO3)2

Asymmetric supercapacitor

CVs of MnO2/AC asymmetric supercapacitor at 2 mV/s

Electrochemical performance of capacitor

Asymmetric supercapacitor

Charge-discharge curves of asymmetric capacitor

electrolyte ： 0.1 mol L-1 Ca(NO3)2

Energy density ： 25 Wh/Kg

C = 45 F/g

C = I t / E

I = 0.5 A/g

Electrochemical performance of capacitor

Thank you so much for your attention!