Battery Control Apparatus Ion Concentration Nonuniformity
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Solution Overview
Problem
Existing battery control methods that adjust the upper limit value based solely on evaluation values may not ensure the required output, as they do not adequately account for the nonuniform ion concentration and material-related deterioration components during high-rate discharge.
Innovation Solution
A control apparatus and method that use a current sensor and controller to detect current values, calculate an evaluation value for ion concentration nonuniformity, estimate material-related deterioration, and adjust the threshold value to permit deterioration associated with the first deterioration component, ensuring the battery output remains within a permissible range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper limit value is reduced when the evaluation value exceeds the target value to suppress deterioration, then the deterioration due to high rate discharge is suppressed, but the output required by the driver may not be ensured
Solution Approach 1:
The upper limit value is dynamically adjusted based on the integral value of evaluation values exceeding the target value, rather than being fixed or adjusted solely based on instantaneous evaluation values. This allows the system to adapt the discharge power limit in real-time based on the cumulative deterioration impact, resolving the contradiction between suppressing deterioration and ensuring required output.
Solution Approach 2:
The system calculates and monitors the integral value of evaluation values in advance before making decisions about reducing the upper limit value. By accumulating deterioration information over time through integration, the system can proactively adjust the upper limit value before severe deterioration occurs, while still maintaining high output capability during normal operation.
2Power
If the upper limit value is set at the maximum value to satisfy dynamic performance, then the vehicle performance requirements are met, but deterioration due to high rate discharge increases
Solution Approach 1:
The system continuously monitors the evaluation value (which reflects ion concentration nonuniformity and deterioration) and uses this feedback to adjust the upper limit value. When the integral of excessive evaluation values reaches a threshold, the upper limit is reduced, creating a closed-loop control system that balances performance and durability through continuous feedback from the battery state.
Solution Approach 2:
The system changes the upper limit value parameter based on the calculated integral value of evaluation values. By transforming the physical state of the battery (ion concentration distribution) into an evaluation value and then into an integral metric, the system dynamically adjusts the discharge power parameter to optimize both performance and durability.
Data Source
AI summary
A control apparatus controlling discharge of a secondary battery such that a discharge power of the secondary battery does not exceed an upper limit value has a current sensor and a controller. The current sensor detects a current value during charge and discharge of the secondary battery. The controller calculates an evaluation value for determining a first deterioration component depending on nonuniformity of an ion concentration in an electrolyte of the secondary battery by using the detection result of the current sensor, and reduces the upper limit value when the integral value of the evaluation values exceeding a target value exceeds a threshold value. The controller estimates a second deterioration component depending on the material of the secondary battery and changes the threshold value such that deterioration due to the first deterioration component is permitted in association with the second deterioration component.