Lithium ion battery

AdvantagesImpressive energy densityGood power densityGood charge/discharge efficiencyLong lifespanNo environmental issues

However, lithium ion battery is sensitive to temperature and could be a risk to fire safety.

The dominant EV battery

High temperatures can be a result of:1.Ambient temperature2.Fast charging3.Drawing large amount of energy from batteries

Lithium ion batteryTemperature problems

Low temperatures can be a result of:Ambient temperature

Temperature gradients can be caused by:Uneven cooling/heating of batteries

Lithium ion batteryTemperature problems

Batteries make up about 70% of the cost of an electric vehicle

Good thermal management can enable longer lifespan, lower costs and improve safety for EV batteries

Thermal ManagementCritical for EV batteries

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No CoolingAir Cooling

Low resistance cells

GCoreLab’s Liquid CoolingGCoreLab’s Liquid Cooling

Source: NREL – Battery Thermal Modeling and Testing

Relative Capacity of Battery vs. Time

GCoreLab’s Liquid Cooling

Battery capacity of 80% for more than 9years

Increased lifespan of 2years compared to Air Cooling

Thermal ManagementCritical for EV batteries

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Chevrolet Volt Ford Focus

Smart fortwo ED Tesla Roadster

Liquid Cooling TechnologyCurrent Users

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Requirements of the thermal system:

1. Temperature (15-40°C)

2. Small temperature range within different battery cells

3. Insulation between battery cells

4. No leakage

5. Light weight (<200kg)

6. Low cost (5-10% of battery cost)

Case StudyThermal Management for Electric Bus

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GCoreLab’s Approach1. Temperature (15-40°C)

- Easily achieved with low flow rates for our liquid cooling/heating system

- Possibility of routing fluid flow to heat sources or cooler regions in vehicle

2. Small temperature range within different battery cells

- Supply of flow to liquid cold plates in a parallel configuration

- Uniform cooling of individual cells

3. Insulation between battery cells

- Insulative thermal interface material

- Overmolding of high thermal conductivity plastics

- Liquid cold plates made out of high thermal conductivity plastics

Case StudyThermal Management for Electric Bus

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GCoreLab’s Approach4. No leakage

- Vacuum brazing

- Liquid cold plate under battery packs

- Pipe connections outside battery box

5. Light weight

- Liquid cold plates made out of aluminium or high thermal conductivity plastics

- Sharing of liquid cold plates amongst individual cells instead of dedicated plates

- Smaller pumps due to lower pressure drops across plates

6. Low cost

- Lower maintenance cost due to smaller pump and lower pressures involved

- Usage of plastic materials instead of the more costly metals

Case StudyThermal Management for Electric Bus

Jacket of minichannels using oblique fins around the battery pack

Thin profile to slot between gaps of the individual cells

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Incorporation in Battery PacksGCoreLab Thermal Solution

Combined system to cool multiple heat generating devices such as motor controllers, ultra-capacitors and motors

Better performance in components

More compact

Lower cost

less equipment

Less weight

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Incorporation in AutomobileGCoreLab Thermal Solution

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Conclusion

High performance thermal management• Higher efficiency, recoverable power and capacity

• Longer battery life/better reliability

• Allows fast charging

• Prevents thermal runaway

• Compact system

Customizable thermal management to incorporate with existing battery packs and components

Thank you!