EV Battery Control Device Preventing Cell Cracks via Deterioration Monitoring
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Solution Overview
Problem
In-vehicle batteries face issues due to electrode expansion caused by deterioration, leading to stress concentration and potential cracking, especially at cell lid welded portions and gas discharge valves, as the reaction force against restraints becomes saturated over time.
Innovation Solution
A control device and storage medium that monitor the deterioration of battery cells by acquiring indicator values such as internal resistance or reaction force, and prohibit charging when these values reach predetermined threshold levels, providing notifications to the vehicle occupant and storing transition data to predict when thresholds will be reached based on usage patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the battery continues to be used without special countermeasures, then the battery can operate for extended periods, but stress concentrates on cell components and cracks may occur due to expansion from deterioration
Solution Approach 1:
The control device performs preliminary actions by monitoring deterioration indicators (internal resistance, reaction force) and predicting future threshold exceedances before they occur. When the indicator is predicted to reach the first threshold value after a predetermined time or distance, the system proactively prohibits charging and notifies the user, preventing stress concentration and potential cracking before they happen.
Solution Approach 2:
The system implements continuous feedback by acquiring deterioration indicator values, comparing them against threshold values, and adjusting charging operations accordingly. The control device monitors internal resistance and reaction force values, provides feedback through notifications to the information output device, and adjusts battery usage by prohibiting charging when thresholds are reached or predicted to be reached, thereby maintaining structural integrity while extending safe operational duration.
2Reliability
If restraints are applied to suppress electrode plate expansion, then battery performance is maintained, but reaction force increases and concentrates stress on cell lid and gas discharge valve
Solution Approach 1:
The system converts the harmful effect of accumulated reaction force into a useful monitoring parameter. By measuring the reaction force exerted by electrode plates on restraints and using it as a deterioration indicator, the system can detect when stress on cell components approaches dangerous levels. This allows proactive intervention by prohibiting charging before stress concentration causes cracking, thereby converting the potentially harmful reaction force into a protective monitoring mechanism.
3Reliability
If charging is prohibited when deterioration indicators reach threshold values, then battery safety is improved, but battery usability is reduced
Solution Approach 1:
The system applies partial action by prohibiting charging only when deterioration indicators reach or are predicted to reach specific threshold values, rather than imposing blanket restrictions. The control device selectively manages charging based on actual battery condition, allowing full charging availability when the battery is healthy and only restricting charging when necessary for safety, thereby minimizing impact on usability while maintaining safety.
Data Source
AI summary
A control device for an electric vehicle, in which a drive battery pack is mounted, the drive battery pack being capable of charging the plurality of battery cells using an external power supply, and the drive battery pack having a battery case for storing a plurality of battery cells in a stacked state, the control device including: a storage device that has stored a program; and a processor connected to the storage device, wherein the processor executes the program stored in the storage device to: acquire an indicator value regarding deterioration of the plurality of battery cells; and perform processing for prohibiting charging of the plurality of battery cells from the external power supply when the indicator value has reached a first threshold value.