Battery Control Device Using Voltage Difference for Charge Restriction
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Solution Overview
Problem
Existing battery control methods fail to reliably prevent performance deterioration in secondary batteries, especially when temperature changes occur during usage, leading to inaccurate charge/discharge restrictions and potential resistance increases.
Innovation Solution
A battery controlling device that calculates the voltage difference between closed-circuit and open-circuit voltages of a secondary battery over predetermined periods and compares this value to a permissible limit, outputting a signal to restrict charge/discharge if exceeded, thereby mitigating temperature-induced performance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature measurement is used to control charge/discharge, then charge/discharge restriction can be implemented, but measurement precision deteriorates due to temperature differences between surface and internal battery
Solution Approach 1:
The patent uses voltage difference as an intermediary parameter to indirectly assess battery state without directly measuring internal temperature. By calculating the difference between open-circuit voltage and closed-circuit voltage, the system obtains information about ion concentration unevenness and actual battery conditions without the need for direct internal temperature measurement, thus resolving the measurement precision problem.
Solution Approach 2:
The patent replaces the mechanical/physical temperature measurement system (thermocouples, thermistors) with an electrical measurement system that uses voltage detection and computation. This substitution eliminates the need for physical contact with the battery interior and avoids the fundamental limitation of surface temperature measurement, thereby improving both measurement precision and reliability.
2Productivity
If high current charge/discharge is performed, then productivity increases, but battery performance deteriorates due to internal resistance increase
Solution Approach 1:
The patent implements a feedback control mechanism where the voltage difference is continuously monitored and used to adjust charge/discharge current in real-time. When the voltage difference exceeds the threshold, the system automatically restricts current, creating a closed-loop control that prevents performance deterioration while maximizing productivity during normal operation.
Solution Approach 2:
The patent employs dynamic current restriction rather than static limits. The charge/discharge current is adjusted based on real-time voltage difference measurements, allowing the system to adapt to changing battery conditions. This dynamic approach enables high current operation when safe and automatically restricts current when deterioration risk is detected, optimizing both productivity and reliability.
Data Source
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AI summary
A battery controlling device includes: a voltage detecting unit configured to detect a closed-circuit voltage of a secondary battery; an open-circuit-voltage computing unit configured to compute an open-circuit voltage of the secondary battery; and an assembled-battery controlling unit configured to discriminate whether a computed value computed based on a voltage difference between the closed-circuit voltage and the open-circuit voltage of the secondary battery in a continuous predetermined period is exceeding a permissible value determined in advance or not. If the computed value is exceeding the permissible value determined in advance, the assembled-battery controlling unit outputs a signal that carries out charge/discharge restriction of the secondary battery.