Battery Charge Voltage Control for Degradation-Adaptive Charging
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Solution Overview
Problem
Existing battery control systems fail to set appropriate upper limit voltages based on the degraded state of batteries, leading to inefficient charging and potential degradation.
Innovation Solution
A battery control device with a degraded battery state estimation unit, storage unit, and upper limit voltage estimation unit that adjusts the upper limit voltage based on the battery's use history, capacity retention rate, and internal resistance increase rate, updating the voltage limits to optimize charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed upper limit voltage is set for secondary batteries, then battery safety is ensured, but charging performance cannot be optimized according to battery degradation state
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed upper limit voltage to a dynamically adjustable upper limit voltage that changes according to the battery's degradation state. The control device estimates the degradation state using multiple parameters (capacity retention rate, internal resistance increase rate, use history) and adjusts the upper limit voltage accordingly, allowing the system to adapt to battery aging while maintaining safety
Solution Approach 2:
The patent implements parameter changes by modifying the upper limit voltage parameter based on the battery's degradation state. Instead of using a single fixed voltage value, the system changes the voltage parameter dynamically according to estimated degradation metrics, enabling optimization of charging performance while ensuring safety through controlled parameter adjustment
2Productivity
If the upper limit voltage is increased to maximize charging capacity, then charging performance improves, but battery degradation and safety risks increase
Solution Approach 1:
The patent applies feedback by continuously monitoring battery parameters (capacity retention rate, internal resistance increase rate, use history) and using this feedback to adjust the upper limit voltage. The control device estimates the degradation state based on measured parameters and feeds this information back to determine the appropriate upper limit voltage, creating a closed-loop control system that balances charging performance and safety
Solution Approach 2:
The system dynamically adjusts the upper limit voltage based on real-time degradation assessment. As the battery degrades, the upper limit voltage is adjusted downward to prevent safety issues, while still allowing maximum safe charging capacity at each stage of battery life. This dynamic adjustment optimizes charging capacity without compromising safety
Data Source
AI summary
A battery control device (an assembled battery control unit 150) has a degraded battery state estimation unit 521, a storage unit 180, and an upper limit voltage estimation unit 1522. The degraded battery state estimation unit 521 estimates a first degraded state of a battery on the basis of at least any one of a use history, a capacity retention rate, and an internal resistance increase rate of the battery and estimates a second degraded state of constituent elements inside the battery with respect to each type of the battery. The storage unit 180 stores information regarding an upper limit voltage of chargeable electric power with respect to each temperature of the battery. The upper limit voltage estimation unit estimates the upper limit voltage of the chargeable electric power of the battery on the basis of the above-described information. The upper limit voltage estimation unit 1522 updates the above-described information on the basis of the first degraded state and the second degraded state.