EV Battery Pre-cooling with Phase Change Material
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Solution Overview
Problem
The recharging of electric vehicle traction batteries is often terminated prematurely due to excessive heat, which limits the battery's state of charge as the charging station terminates recharging when the battery temperature reaches a maximum allowable temperature.
Innovation Solution
A method and system for pre-cooling the traction battery by using a Phase Change Material (PCM) surrounded by a refrigerant coolant, controlled by a controller that detects proximity to the charging station and discharge rate, to lower the battery temperature before arrival, allowing for extended recharging without exceeding the maximum temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recharging is performed at high rate to quickly restore battery energy, then the state of charge increases rapidly, but the battery temperature rises to maximum allowable temperature causing premature termination of recharging
Solution Approach 1:
The system performs preliminary cooling of the battery using PCM before high-rate recharging begins. The controller detects when the vehicle is approaching a charging station and activates the cooling system in advance, lowering the battery temperature so that when fast charging starts, the battery can absorb more heat before reaching the maximum temperature threshold, thereby enabling higher state of charge achievement.
Solution Approach 2:
The patent utilizes phase change material (PCM) that transitions from solid to liquid phase during the cooling process. The PCM absorbs latent heat from the battery as it melts, providing efficient cooling without requiring continuous energy input. This phase transition mechanism enables rapid heat absorption to maintain battery temperature within acceptable limits during high-rate recharging.
2Temperature
If battery cooling is performed continuously to maintain low temperature, then the battery temperature remains below maximum limit, but energy is consumed during driving to operate the cooling system
Solution Approach 1:
Instead of continuous cooling during driving, the system performs cooling in advance when the vehicle is approaching a charging station. The controller monitors vehicle location and charging station proximity, activating the cooling system only when needed before recharging begins. This on-demand preliminary cooling approach maintains battery temperature without continuous energy consumption during normal driving operations.
Solution Approach 2:
The PCM-based cooling system is self-regulating through its phase change properties. Once the PCM is cooled to its phase transition temperature, it automatically begins absorbing heat from the battery as it melts, providing passive cooling without requiring continuous active control or energy input. The system leverages the inherent thermodynamic properties of the PCM to maintain battery temperature.
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 enables the traction battery to be cooled to a target temperature upon arrival at the charging station, allowing for a greater state of charge to be achieved without premature termination of recharging, thus enhancing the battery's range and fast-charge capabilities.
Implementation Method 1
The PCM may be configured to convert from a liquid state to a solid state as the PCM is being cooled to thereby pre-cool the traction battery
Implementation Method 2
cooling a phase change material ("PCM") surrounding at least a portion of the traction battery by circulating refrigerant coolant to the PCM to cool the PCM
Implementation Method 3
cooling a phase change material ("PCM") surrounding at least a portion of the traction battery by circulating refrigerant coolant to the PCM to cool the PCM
Data Source
AI summary
A method and system for an electric vehicle include a controller and a battery cooling system. The controller automatically detects when the vehicle is being driven to a charging station. The controller controls the battery cooling system to pre-cool a traction battery of the vehicle as the vehicle is being driven to the charging station so that the traction battery is cooled to a target temperature upon the vehicle reaching the charging station. The battery cooling system includes a phase change material (PCM) surrounding at least a portion of the traction battery. The traction battery is pre-cooled by circulating refrigerant coolant to the PCM to cool the PCM and thereby pre-cool the traction battery.