Analysis method for vehicle-mounted battery pack pressure difference problem

Abstract

The invention discloses an analysis method for a vehicle-mounted battery pack pressure difference problem. The method includes firstly, analyzing the battery and finding out a failure module; secondly, testing the static voltage and the internal resistance of the failure module, wherein the failure module is divided into a failure module which is lower than the normal use voltage range but is higher than 0V, a failure module in a normal use voltage range and a failure module close to 0V according to the different static voltages; finally, finding out the failure cell from the failure module, dissembling the failure cell, and analyzing the failure reason and making the improvement. The method has the beneficial effects that starting from the differential pressure large fault module, the failure cell of the failure module can be analyzed through the capacity, direct-current internal resistance, disassembly, self-discharge analysis aspects, and the root cause of the cell failure is foundthrough disassembly of the cell, the cell production is guided to improve the cell quality, and the failure rate of the battery pack pressure difference is fundamentally reduced.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for analyzing the problem of large pressure difference in vehicle-mounted battery packs. Background technique [0002] After statistical analysis of the causes of power lithium battery failures, failures due to large pressure differences account for more than 80%. The problem of inconsistent cell voltage has become one of the main technical problems that power lithium battery enterprises must overcome first. [0003] At present, the usual methods to solve the inconsistent cell voltage are: 1. Use the cell voltage difference as an important criterion for the screening of battery production matching groups, and minimize the voltage difference in the battery pack. 2. Perform dynamic correction by implanting a balancing circuit into the battery pack. The currently used equalization circuits, whether active or passive, have unsatisfactory effects. The main per...

AI Technical Summary

Problems solved by technology

The currently used equalization circuits, whether active or passive, have unsatisfactory effects. The main performance is that the equalization current is small and the equalization time is short. In addition, the equalization circuit is also stable, which will undoubtedly increase the failure of lithium batteries. Probability (protection failure rate is about 20%)

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