Battery Charging Method Balancing Voltage Imbalance
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Solution Overview
Problem
Battery modules age prematurely due to voltage imbalances among batteries, leading to suboptimal charging and reduced service life, as the maximum voltage triggers overvoltage protection before all batteries reach saturation.
Innovation Solution
A charging method that adjusts the charging voltage and taper voltage values by calculating the difference between maximum and minimum battery voltages, ensuring all batteries reach charging saturation, thereby balancing voltage values and prolonging battery module life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional charging method is used, then charging speed is maintained, but battery voltage imbalance occurs leading to premature aging
Solution Approach 1:
The system performs preliminary detection of battery voltage values before completing the charging process. By detecting voltage imbalances during charging and proactively adjusting the taper voltage value, the system prevents voltage imbalance from causing premature termination, thereby extending battery module service life without significantly impacting charging efficiency
Solution Approach 2:
The system dynamically adjusts the taper voltage value based on detected battery voltage imbalances. When voltage difference exceeds a threshold, the taper voltage is reduced to allow lower-voltage batteries to reach saturation, transforming the fixed voltage parameter into a dynamic one that adapts to real-time battery states
2Reliability
If charging stops when maximum voltage reaches overvoltage protection threshold, then overcharging is prevented, but other batteries cannot reach saturation state
Solution Approach 1:
The system applies different voltage thresholds to different batteries based on their individual voltage levels. Instead of using a uniform overvoltage protection threshold for all batteries, it calculates a customized taper voltage value for each battery considering its relative state of charge, allowing batteries with lower voltages to continue charging to saturation while maintaining overvoltage protection for batteries near their maximum voltage
Solution Approach 2:
The overvoltage protection mechanism transitions from a static fixed threshold to a dynamic adaptive threshold. The taper voltage value is dynamically adjusted based on real-time detection of battery voltage imbalances, enabling the system to flexibly determine when each battery should reach its charging limit
3Device complexity
If fixed taper voltage value is used, then charging control is simple, but voltage imbalance cannot be corrected
Solution Approach 1:
The system automatically detects battery voltage values and self-adjusts the taper voltage value without requiring external intervention. The control unit autonomously compares detected voltage values, determines voltage imbalances, and modifies the taper voltage accordingly, enabling the charging system to self-correct voltage imbalances while maintaining relatively simple control logic
Data Source
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AI summary
A charging method is provided for charging a plurality of batteries of a battery module. The charging method includes: obtaining a maximum voltage value and a minimum voltage value of a plurality of battery voltage values of the batteries according to a relative state of charge of the battery module during a charging process; obtaining a difference value between the maximum voltage value and the minimum voltage value; and adjusting a charging voltage value for charging the batteries and a taper voltage value for determining whether the batteries reach a charging saturation state according to the difference value.