automotive battery egvi expert workshop€¦ · automotive battery ... air cathode before and after...
TRANSCRIPT
Automotive Battery – EGVI Expert Workshop
Dr. Ulrich Mähr
Volkswagen AG, Group Research Battery
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High voltage lines
Electrical brake power assist
Cooling
Cross-linking of components
Heating
Power electronics E-Motor and transmissionTraction battery and
battery managment
Infotainment
Remote-steering / online services
Spectrum of new technologies for electric vehicles
3
Battery activities Volkswagen Group Research
Air cathode before and after discharge
Li-ion batteries gen. 1 and 2
Gen 1:
• Benchmark (energy and power, safety)
• Analytics
• Aging models
Gen 2:
• New materials, new cell types
After Li-ion technologies
• Li – sulfur
• Li – oxygen
Safety
failure, accident,
abuse, maintainance,
comfort, reliability
Costs
profitability,
market acceptance
recycling
Energyelectrical driving range,
availability of comfort devices
charging time and infrastructure
driving power,
performance,
dynamics
Power
Durabilitycycles, lifetime
Battery requirements for automotive applications
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Safety
failure, accident,
abuse, maintainance,
comfort, reliability
Costs
profitability,
market acceptance
recycling
Energyelectrical driving range,
availability of comfort devices
charging time and infrastructure
driving power,
performance,
dynamics
Power
Durabilitycycles, lifetime
Battery requirements for automotive applications
5
Hazard
Level
Description
0 No effect
1Passive protection
devices activated
2 Defect / damage
3 Leakage
4 Venting
5 Fire or flame
6 Rupture
7 Explosion
Requirements for the cell: Hazard Level ≤ 4
6
Challenges
• Used materials are sufficient
safe, for improvement of life time
and energy density also new safe
materials have to be developed
• Today safety is ensured by
large efforts on system level
Safety of Li-Ion technology
Research
necessity• Further development of protective mechanisms (cell, module, system)
• Development of intrinsically safe materials
Simulation of a
rear-crashtime [ms]
Accele
ratio
n [g]
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Lithium-plating and dendrite growth
Intact area
Molten and
recoagulated
fibre
Separator
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Damages on cell level during
applicationrare but normal use
• Short cut of anode and cathode by
Lithium dendrites
• Closed pores in the separator
• Melting and recoagulation of the
polymer
Damaged area
Safety
failure, accident,
abuse, maintainance,
comfort, reliability
Costs
profitability,
market acceptance
recycling
Energyelectrical driving range,
availability of comfort devices
charging time and infrastructure
driving power,
performance,
dynamics
Power
Durabilitycycles, lifetime
Battery requirements for automotive applications
9
Challenges
• Consideration of special ambient conditions
Temperature (e.g. South Africa, Northern
Sweden)
Driving strategy (current, Depth of discharge,
SOC, etc.)
• Reliable durability prognosis is needed
(10 …15 years)
• Combination of aging effects in the highly complex
system of a Li-ion cell
Life time of Lithium-Ion cells
Research
necessity• Enhanced life time by materials research
• Development of prediction models for aging behaviour
Laboratory for cell and
battery testing
(VW Gorup Research)
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Aging effects in lithium-ion cells
Influencing parameters for
aging of Li-ion cells
• Temperature
• Time
• Voltage (SOC)
• Current, power
• Charge- and discharge
levels
• Anode, cathode material
• Electrolyte, additives
• Cell type (pouch
prismatic, cylindrical)
• …
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Re
lative
ca
pa
city [%
]
Re
lative
ca
pa
city [%
]
Cycle number
Cycle number
Status / Challenges
• Temperature requirements of automotive
applications differ from consumer
electronics:
Consumer electronics: 0°C to 50°C
Automotive requirement: -30°C to 60°C
• Physics of electrolyte/solvent systems is
limiting factor (cristallization)
Power capability at low temperatures
Research
necessityConsiderable expansion of operating temperatures by novel
electrolytes
Schematic graph: abrupt power decrease of
known Li-ion cells at low temperatures.
Temperature -30°C 23°C 60°C
Po
we
r
Minimum requirement EV
Typical behaviour of
a Li-Ion cell
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Voltage (SOC)
Current, power
Temperature
Time
Charge and discharge levels
0
20
40
60
80
100
0 100 200Cycle number
En
erg
y/ P
ow
er
rate
Cell chemistry
Cell type (pouch, prism., cyl.)
Aging model Application
Voltage (SOC)
-80 -60 -40 -20 0 20 400
1k
2k
3k
4k
5k
6k
Cou
nt
P_Batt [kW]
Power / currents
Temperature
Recovery time
Charge and discharge levels
Target• Reliable life time prediction in real vehicle operation on basis of
laboratory measurements and simple technical operation data
Frequency of …
Verification
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Thank you!
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