Capacity stabilizing method of lithium ion battery during low-temperature HPPC test

Abstract

The invention relates to a capacity stabilizing method of a lithium ion battery during a low-temperature HPPC test. The method comprises following steps of S1, placing the battery in a 25 DEG C environment cabin so as to allow the battery to achieve heat balancing; S2, emptying the battery capacity in the 25 DEG C environment cabin and allowing the battery to stand for 1h; S3, fully charging the battery in a way of converting constant current to constant voltage in the 25 DEG C environment cabin; S4, placing the battery in a -20 DEG C environment cabin so as to allow the battery to achieve heat balancing; S5, discharging the battery in the -20 DEG C environment cabin with 1C and then allowing the battery to stand 1h; S6, repeating the S5 and stopping the discharging until the voltage of the battery reaches 2.8 V; and S7, obtaining the battery capacity which is the sum of the discharging capacity accumulated through the steps of S5-S6. According to the invention, the method is simple and feasible; in the discharging process, due to the short-term discharging, the temperature of the cell is always maintained in a -20 DEG C environment, so the discharging capacity of the cell will notbe increased caused by accumulation of the heat in the discharging process; the following low-temperature HPPC test is quite accurate; and the test results are quite reliable.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for constant volume of lithium-ion batteries during low-temperature HPPC testing. Background technique [0002] With the successive introduction of fuel vehicle sales restriction policies in various countries, electric vehicles will become the mainstream in the future, and the supply of lithium-ion batteries will also increase. In order to facilitate the docking of vehicle manufacturers, the power matrix of lithium-ion batteries is the Automobile companies are very concerned about the data when designing the BMS control system. The power matrix table mainly includes the DC internal resistance and power data of the battery cell at different temperatures and different SOC (State of Charge). However, at low temperatures, due to the excessive internal resistance of the battery cell, more heat is generated during continuous discharge, resulting in The battery c...

AI Technical Summary

Problems solved by technology

The power matrix table mainly includes the DC internal resistance and power data of the battery cell at different temperatures and different SOC (State of Charge). However, at low temperatures, due to the excessive internal resistance of the battery cell, more heat is generated during continuous discharge, resulting in The battery capacity is too high, resulting in a large data deviation in the follow-up HPPC (The Hybrid Pulse Power Characterization, hybrid pulse power performance test) test

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