Method for testing specific heat capacity of lithium ion battery

Abstract

The invention relates to a method for testing specific heat capacity of a lithium ion battery. The method comprises the following steps: measuring and recording open-circuit voltage and surface temperature of the battery in different SOC (State of Charge) states till the SOC of the battery is equal to 0, performing regression analysis on data representing that the open-circuit voltage of the battery changes along with the surface temperature in the different SOC states, so as to obtain a fitting relationship equation of the open-circuit voltage, open-circuit voltage temperature coefficients and different discharge times of the battery, calculating the open-circuit voltage and the open-circuit voltage temperature coefficients at different recorded time points in corresponding discharge by using the relationship equation, calculating heating power of the battery in discharge at each time point, calculating a released thermal value, calculating the SOC states of corresponding moments according to the discharge time and the discharge power so as to obtain the specific heat capacity in the different SOC states. The change of the specific heat capacity of the battery along with the SOC is obtained by using a method with the combination of experimental testing and statistics calculation, and the method is simple and convenient to execute, low in testing cost and wide in application range.

Description

technical field [0001] The invention belongs to the technical field of specific heat capacity of lithium-ion batteries, and in particular relates to a test method for specific heat capacity of lithium-ion batteries. Background technique [0002] Lithium-based batteries are particularly favored by manufacturers of electric vehicles and electric mopeds because of their long service life, harmlessness to the environment, high specific energy, and high conversion rate. In the application of power battery packs, the thermal performance of lithium batteries is an important factor affecting the cycle life and safety of battery packs. [0003] At present, the specific heat capacity test of lithium-ion batteries mainly relies on the accelerated calorimeter, but due to the size limitation of the sample pool of the accelerated calorimeter equipment, the specific heat test for large-sized batteries cannot be carried out, the test cost is expensive, and the specific heat capacity during ...

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Problems solved by technology

[0003] At present, the specific heat capacity test of lithium-ion batteries mainly relies on the accelerated calorimeter, but due to the size limitation of the sample pool of the accelerated calorimeter equipment, the specific heat test for large-sized batteries cannot be carried out, the test cost is expensive, and the specific heat capacity during the discharge process cannot be obtained. SOC changes

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