Battery Pack Deterioration Control via Internal Resistance
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Solution Overview
Problem
Existing methods for charging secondary batteries do not accurately calculate the deterioration coefficient, leading to inadequate control over charge conditions, which accelerates battery deterioration due to prolonged high voltage states and is influenced by storage, usage conditions, and temperature.
Innovation Solution
A battery pack and charger system that includes a measuring section to detect voltage, current, and internal resistance, a controller to calculate the deterioration coefficient by comparing the measured internal resistance to the initial resistance, and dynamically adjust the charge conditions, such as charging current and voltage, to mitigate battery deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fixed charging current and voltage values are used in constant-current constant-voltage method, then charging process is simple to control, but battery deterioration accelerates due to prolonged high voltage states when internal resistance increases
Solution Approach 1:
The patent applies dynamics by transitioning from fixed charging parameters to dynamic adjustment based on battery state. The charging current and voltage are continuously adjusted according to the calculated deterioration coefficient, which is derived from internal resistance measurements. This allows the charging system to adapt to the battery's changing conditions, preventing prolonged high voltage states that accelerate deterioration while maintaining effective charging control.
Solution Approach 2:
The patent implements feedback by measuring the battery's internal resistance during charging, calculating the deterioration coefficient from this measurement, and using this coefficient to adjust the charging parameters. This closed-loop feedback mechanism enables the system to respond to the battery's actual condition, extending the constant-current charging phase and reducing the constant-voltage phase to minimize high voltage exposure and accelerate charging while protecting battery health.
2Loss of time
If internal resistance measurement method is used to determine battery deterioration, then deterioration can be determined quickly, but accurate calculation of deterioration coefficient is difficult due to influence from storage conditions, usage patterns, and temperature
Solution Approach 1:
The patent applies parameter changes by using internal resistance as a measurable parameter that correlates with battery deterioration. By measuring internal resistance at different charging stages and comparing it to initial values, the system calculates a deterioration coefficient that reflects the battery's actual condition. This approach transforms the difficult-to-measure concept of 'battery deterioration' into a quantifiable parameter based on electrical resistance, enabling quick and accurate assessment despite variations in storage and usage conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate calculation of the deterioration coefficient, enabling dynamic control of charge conditions to prevent prolonged high voltage states, thereby suppressing battery deterioration and enhancing battery stability.
Implementation Method 1
a measuring section to detect a voltage, a current, and an internal resistance, of the secondary battery
Data Source
AI summary
A battery pack includes a secondary battery including a plurality of cell blocks, a measuring section, a charge and discharge control switch, a protection circuit, and a memory. The measuring section detects a voltage, a current, and an internal resistance, of the secondary battery. The controller monitors the voltage and the current of the secondary battery and outputs a request signal indicative of a charge condition to charge the secondary battery in accordance with the charge condition which is set. The protection circuit monitors voltages of the plurality of cell blocks. The memory registers an initial internal resistance of the secondary battery. The controller calculates a deterioration coefficient by a ratio of the internal resistance detected by the measuring section to the initial internal resistance registered in the memory, and changes the charge condition in accordance with the deterioration coefficient.