Lithium ion battery capacity detection and direct-current internal resistance detection method

Abstract

A lithium ion battery capacity detection and direct current internal resistance detection method comprises the following steps: placing a battery on a capacity DCIR detector, fully charging the battery with a 1C current in a constant current and constant voltage mode, putting the battery aside, completely discharging the battery with a 1C current in a constant current mode, and recording the discharge capacity as C; putting the battery aside after the capacity detection is completed, and performing constant-current charging on the battery by using 20-80% of the shipment state-of-charge SOC ofthe battery, the charging quantity being the shipment SOC; and putting the battery aside, discharging the battery with a 3C current in a constant current mode, putting the battery aside, and chargingthe battery with a 3C current in a constant current mode, wherein the capacity DCIR detector can calculate points at will in the discharging and charging process, and a DCIR value is obtained by calculating the voltage difference and the current difference. According to the invention, capacity detection and DCIR (Direct Current Internal Resistance) detection are completed by one device, the production efficiency is high, only one action of putting the battery on a cabinet and taking the battery down from the cabinet and one grading action need to be carried out, and the device investment cost,the later maintenance cost and the labor hour cost of operators are saved.

Description

Technical field [0001] The invention belongs to the technical field of storage batteries, and specifically relates to a method for detecting the capacity of a lithium battery and the DC internal resistance DCIR. Background technique [0002] As the mainstream battery of electric vehicles, battery capacity and DC internal resistance DCIR have a very important influence when determining its charging strategy. In the prior art, the lithium battery capacity detection and the DC internal resistance DCIR detection are completely separated, and are completed independently by two devices, the capacity division cabinet and the DCIR detector. Capacity detection is to charge the battery with constant current and constant voltage through the capacity-dividing cabinet. After a certain period of time, the battery is discharged with constant current and the discharged power is the capacity of the battery; DC internal resistance DCIR detection: Use 1~3C current to charge the battery Perform con...

AI Technical Summary

Problems solved by technology

The deficiencies of the existing technology are: 1. There are many grades when the battery capacity is tested in the cabinet, and different gears are tested on the DCIR detector, and then there are many gears for secondary classification, which is not convenient for production management; 2. Battery capacity detection It is necessary to complete the action of loading and unloading the cabinet once, and DCIR needs to complete the action of loading and unloading the cabinet again. It needs to be transported between the capacity detection and the DCIR detection, resulting in waste of time, actions and personnel, and low efficiency; 3. The battery capacity detection and DCIR detection are separated, and two different devices need to be purchased. The cost of equipment and later maintenance costs will increase by at least 30%, and the waste of investment costs

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