Method for evaluating heat release of lithium ion battery

Abstract

The invention discloses a method for evaluating the heat release of a lithium ion battery. The method comprises the steps that the lithium ion battery is disassembled to obtain a positive electrode sheet, a negative electrode sheet and a separator; the positive electrode sheet, the negative electrode sheet and the separator are washed and dried; and the positive electrode sheet and the negative electrode sheet are sliced, the sliced positive electrode sheet, the sliced negative electrode sheet, the separator and electrolyte are assembled into a miniature full battery, the miniature full battery is used for testing, the overall heat release condition of an entire complex system in the lithium ion battery can be obtained, and the problem that actual situations cannot be reflected by separately testing electrode materials is solved, so that basic data are provided for the design of high-security battery cells.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery testing, in particular to a method for evaluating the heat release of a lithium-ion battery. Background technique [0002] In order to cope with the continuous improvement of the mileage requirements of new energy vehicles, power batteries have been developing in the direction of high energy density. As the energy density of a single battery cell moves towards 300Wh / kg, the safety of the battery cell has become one of the important factors restricting the further improvement of the energy density. Therefore, the thermal safety assessment of batteries has become the focus of research in the lithium battery industry, and the heat release and heat release rate of batteries are the focus of research on the thermal safety of lithium-ion batteries. [0003] When the lithium-ion battery heats up, the internal reaction is very complicated, involving the consumption and regeneration of the neg...

AI Technical Summary

Problems solved by technology

The heat release of the material can be calculated by the temperature change and specific heat capacity of the material, but the specific heat capacity changes due to the structural change of the material itself during the test process, and the heat release of the material obtained through the temperature change will lead to changes in the authenticity of the results. Moreover, the temperature rises slowly during the adiabatic test (usually 0.02°C / min), takes a long time (usually more than tens of hours), and the ARC equipment is expensive, resulting in a low cost-effectiveness ratio of the experiment

[0006] It can be seen that in the past thermal tests of lithium-ion batteries, no matter whether ARC test or DSC test was used, the four main materials of the battery cell (positive electrode, negative electrode, separator and electrolyte) were tested separately or in combination. , due to the mutual promotion of the reactions between the main materials of the battery, the heat release of the materials obtained by separate tests cannot fully reflect the real heat release of the battery

Moreover, ARC equipment is expensive and the test time is long, resulting in a low cost-effectiveness ratio of the experiment

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