Traction Battery Pre-cooling for Rapid EV Charging
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Solution Overview
Problem
The existing cooling systems for traction batteries in electric vehicles are inefficient at maintaining battery temperature during rapid charging, as they lack sufficient cooling capacity when the vehicle is parked at a charging station, leading to potential overheating and the need to slow or inhibit the recharging process.
Innovation Solution
A method and system that pre-cools the traction battery while the vehicle is being driven to a charging station, using a controller to adjust the cooling based on distance, recharging rate, battery temperature, and state of charge, leveraging increased airflow for effective cooling before rapid charging begins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling system operates at full capacity during rapid charging, then the battery temperature can be maintained within safe limits, but the energy consumption increases and the system complexity increases
Solution Approach 1:
The cooling system is activated before the vehicle reaches the charging station to pre-cool the battery, reducing the cooling demand during rapid charging. This preliminary action allows the battery to start charging at a lower temperature, enabling faster charging rates without exceeding temperature thresholds and reducing the need for continuous high-capacity cooling operation.
Solution Approach 2:
The cooling system operates intermittently rather than continuously, switching between active cooling phases and passive cooling phases. During driving to the charging station, cooling is activated periodically to reduce battery temperature, then deactivated during charging if temperature remains within acceptable ranges, thereby reducing overall energy consumption while maintaining temperature safety.
2Temperature
If the cooling system is designed with high cooling capacity for rapid charging, then the battery temperature can be maintained during fast charging, but the hardware cost and system complexity increase
Solution Approach 1:
The cooling system performs pre-cooling of the battery before rapid charging begins, which reduces the thermal load during charging. This allows the use of a less complex cooling system design, as the peak cooling demand during charging is reduced by the preliminary cooling action performed during driving to the charging station.
Solution Approach 2:
The cooling system incorporates variable capacity operation, dynamically adjusting between high-capacity cooling during pre-cooling phases and reduced or zero cooling during charging phases. This dynamic operation allows a single cooling system to handle varying thermal demands without requiring continuously high capacity, thereby reducing overall system complexity and hardware costs.
3Speed
If rapid charging is performed without pre-cooling, then the charging speed is maintained, but the battery temperature exceeds safe limits requiring charging to slow or stop
Solution Approach 1:
The cooling system activates before the vehicle arrives at the charging station to pre-cool the battery, ensuring the battery starts charging at a lower temperature. This preliminary cooling action enables sustained rapid charging speeds without temperature excursions that would force charging to slow or stop, as the battery has thermal headroom to absorb charging heat generation.
4Temperature
If the cooling system operates continuously to maintain battery temperature, then the battery temperature remains within limits, but the energy consumption from the battery increases, reducing driving range
Solution Approach 1:
The cooling system operates periodically rather than continuously, activating during driving to the charging station to reduce battery temperature, then deactivating during charging or when temperature is acceptable. This periodic operation significantly reduces energy consumption from the battery compared to continuous operation, thereby preserving driving range while still maintaining temperature within safe limits when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach maintains the battery temperature within safe limits during recharging, allowing for faster and uninterrupted charging without the need for cooling system operation in all cases, thereby extending battery life and reducing hardware costs.
Implementation Method 1
The battery cooling system may include a coolant pump, a radiator, and hoses to circulate coolant through the battery pack
Implementation Method 2
the radiator, and hoses to circulate coolant through the battery pack
Implementation Method 3
the radiator dissipates heat from the coolant to the surrounding air
Implementation Method 4
circulate coolant through the battery pack
Data Source
AI summary
Methods and systems for electric vehicles, such as a battery electric vehicle (BEV) and a plug-in hybrid electric vehicle (PHEV), include pre-cooling a traction battery of the vehicle upon an indication that the vehicle is being driven to a charging station. The pre-cooling is done by an on-board battery cooling system. The pre-cooling depends on the distance between the vehicle and the charging station.