Method for pre-measuring volume of lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, in particular to a method for pre-measuring the volume of a lithium ion battery. The method comprises the steps of: taking at least two batteries to be formulated, measuring the volumes of the two batteries and calculating the average value Cm of the volumes; after the batteries are formulated and aged, charging the batteries to a preset SOC (stage of charge) and standing still to measure the OCV (open-circuit voltage); and determining the volume of the batteries according to the OCV and Cm. The method takes the OCV value of the special SOC of the batteries as input, calculates the pre-measuring volume according to a pre-measuring formula, and can be applied to pre-measuring the volume of lithium ion batteries of different types and volumes, wherein the average pre-measuring error is within 3%, which is smaller than 5% permitted in application of industrial production. The method, on the one hand, solves the problems of long volume test period, large energy consumption, occupancy of a large number of plants and staffs and high production cost in existing industrial application, and on the other hand, overcomes the deficiencies that the volume test steps are miscellaneous with complex and profound theories in laboratory studies and are not appropriate for industrial application.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a method for predicting the capacity of lithium ion batteries. Background technique [0002] With the wide application and rapid development of various portable electronic devices and electric vehicles, their demands on their power systems—chemical power sources have increased dramatically, and the performance requirements for chemical power sources have also become higher and higher. Because of its high energy density, long cycle life, high average output voltage, large output power, superior cycle performance, long service life and environmental protection, lithium-ion batteries have been used in mobile electronic devices, electric vehicles, space and portable Equipment and other fields, and is expected to play a role in the field of electric energy storage. [0003] At present, there are many technical indicators for evaluating the quality of the battery, among ...

AI Technical Summary

Problems solved by technology

Due to the large number of input factors, the model is complex, and it is difficult to be practical. However, the open circuit voltage method that has been reported so far has a good effect in estimating the SOC (battery state of charge) at the initial and final stages of charging, and it needs to be used in combination with other methods.