Battery Control Device for Internal Resistance Calculation
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Solution Overview
Problem
Existing battery control systems face challenges in determining the end-of-life of batteries with non-uniform internal resistance value increase rates, leading to potential errors in determining battery health due to varying energization times and temperatures.
Innovation Solution
A battery control device that sets a calculation invalid time based on the characteristics of internal resistance increase rates, ensuring valid calculations only when energization time exceeds a predetermined threshold, thereby stabilizing the internal resistance value assessment regardless of energization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If internal resistance value is calculated continuously during charging/discharging, then measurement precision is improved, but reliability deteriorates due to non-uniform increase rates during transient states
Solution Approach 1:
The patent applies preliminary action by setting a predetermined time period threshold before performing internal resistance calculations. The control device checks whether the elapsed time since the last charge/discharge operation exceeds this threshold, and only calculates internal resistance when the condition is met. This preliminary time-check action prevents calculations during transient states, ensuring reliable measurements for end-of-life determination.
2Productivity
If calculation is performed at any energization time, then productivity is improved, but measurement precision deteriorates due to transient state interference
Solution Approach 1:
The patent applies parameter changes by using the elapsed time since the last charge/discharge operation as a control parameter. The control device changes its calculation behavior based on whether this time parameter exceeds a predetermined threshold. This parameter-based control ensures that internal resistance calculations are only performed when the battery is in a stable state, improving measurement precision while maintaining monitoring efficiency.
Data Source
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AI summary
A battery monitoring device includes: a current detection unit that detects an electric current flowing through a battery; a voltage detection unit that detects a voltage between both ends of the battery; a temperature detection unit that detects the temperature of the battery; an internal resistance increase rate calculation unit that calculates the internal resistance increase rate of the battery based on the detected electric current, voltage between the both ends, and temperature; and a calculation invalid time setting unit that sets a predetermined calculation invalid time according to the characteristics of the internal resistance increase rate. The calculation results of the internal resistance increase rate is invalidated for an invalid period from the start of charging or discharging of the battery to the lapse of the calculation invalid time.