Lithium Battery Matching via Voltage Difference Grading
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Solution Overview
Problem
Current methods for equalizing and matching lithium secondary batteries face challenges in controlling the range of consumable current, leading to inconsistent state of charge and reduced reliability of battery groups, with high equalization costs and inefficient charging processes.
Innovation Solution
A method that uses the full charge state consumable current as a control standard, correlating it with voltage differences to grade battery cells, and designs the equalization current and charger cut-off current to match the consumable current range, ensuring consistent state of charge and extended battery group service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the requirement for consistency is set too high for battery matching, then the reliability of the matched battery group is improved, but the pass rate of available batteries becomes low
Solution Approach 1:
The patent applies preliminary action by measuring and recording the voltage of each battery cell before assembly, then using this pre-measured voltage data to screen and match batteries. This allows the sorting system to predict consumable current based on voltage characteristics, enabling reliable matching without requiring extensive post-assembly testing, thus maintaining high reliability while improving pass rate.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical testing system that measures actual consumable current through lengthy charging-discharging cycles with a voltage-based prediction system. By substituting direct consumable current measurement with voltage measurement and prediction algorithms, the system achieves reliable battery matching without the time-consuming and resource-intensive traditional methods, thereby improving both reliability and productivity.
2Productivity
If the requirement for consistency is set too low for battery matching, then the pass rate of available batteries is improved, but the reliability of the matched battery group becomes low
Solution Approach 1:
The patent implements feedback by continuously monitoring the voltage of battery cells during storage and使用前 periods, then using this feedback information to adjust and optimize the matching process. The system records voltage changes over time and uses this data to refine predictions of consumable current, ensuring that even with lower consistency requirements, the matched battery groups maintain reliable performance through data-driven adjustments.
3Ease of operation
If grade dividing is based on voltage difference, then the measurement process is simplified, but the accuracy of dividing grades according to battery self-consumption is reduced
Solution Approach 1:
The patent introduces voltage as an intermediary parameter that correlates with consumable current. Instead of directly measuring consumable current through complex charging-discharging cycles, the system uses voltage measurement as an intermediary that can predict consumable current characteristics. This intermediary approach simplifies the measurement process while maintaining adequate accuracy for practical battery matching applications.
Solution Approach 2:
The patent changes the measurement parameter from direct consumable current measurement to voltage measurement. By shifting from measuring the actual current consumption over time to measuring the electrical potential difference, the system achieves a simpler, faster, and sufficiently accurate method for grading batteries according to their self-consumption characteristics.
4Productivity
If the range of consumable current of battery cells is not controlled, then the battery group can be assembled quickly, but the state of charge becomes inconsistent and service life is reduced
Solution Approach 1:
The patent applies preliminary action by measuring and recording the voltage of each battery cell before assembly, then using this pre-measured voltage data to screen and match batteries. This allows the sorting system to predict consumable current based on voltage characteristics, enabling reliable matching without requiring extensive post-assembly testing, thus maintaining high reliability while improving pass rate.
Data Source
AI summary
In the present invention, a method and system for equalizing and matching lithium secondary batteries belong to the field of secondary batteries. A lithium secondary battery is divided into more than one grade according to the magnitude of a consumable current Ic, the number of grades is h, the lithium secondary battery is divided into grades corresponding to the consumable current according to the magnitude of a voltage difference ΔV, a battery cell at a grade same as that of the consumable current and the voltage difference is selected for matching, so the range of the consumable current of the battery group can be controlled. The battery system configured in the method of the present invention converts consumable current grading into voltage difference grading after laying, so as to be convenient and swift; the range of the consumable current of the battery cell, the laying time, the equalization charging period, the equalization current, and the charger cutoff current are all under control, and are matched with each other, the equalization cost is low, and the charging equalization time is short; the laying service life and the maintenance period of the battery group can be designed or predicted during matching, and how many times of charging/discharging is required to charge the battery group to be balanced after the battery group is laid for an extremely long time is estimated in advance; the battery group reject rate is reduced, and the battery group reliability is improved.