Method and apparatus for detecting inner pressure of lithium ion battery

Abstract

The invention relates to a method and device for detecting internal pressure of a lithium ion cell, which are characterized in that: formula (P0*V0=P1*(V0+deltaV), temperature is constant) is enacted on the basis of Boyle law, wherein P0 is internal gas pressure of the cell, V0 is volume of internal gas of the cell under pressure P0, P1 is atmospheric pressure, and deltaV is change quantity of internal gas volume of the cell under atmospheric pressure. The detecting method includes steps: 1. measuring the change quantity deltaV of the internal gas volume of the cell; 2. measuring the internal gas volume V0 of the cell; 3. calculating the internal gas pressure P0 of the cell. A device for detecting deltaV is constituted of a gas discharge pipeline with a cell clip, a gas transmission pipe, a glass burette with scale, a three-valve rubber pipette bulb, a water tank and an iron support. The method and the device realize real time, effective and accurate measurement for internal pressure of the cell, instruct improvement of cell body structure and safety valve design, and ensure elimination of safety hidden trouble.

Description

Technical field [0001] The invention relates to a method and device for detecting the performance of a lithium ion battery, in particular to a method and device for detecting the internal pressure of a lithium ion battery. Background technique [0002] With the wide application of lithium-ion batteries, more and more people pay more attention to their safety. Lithium-ion batteries are a closed reaction vessel, due to internal chemical or physical effects in different environments during processing, performance testing and use. Gas is generated, and the accumulation of gas causes the internal pressure of the battery to rise. Therefore, the ultimate pressure design of the safety valve must be within a safe range. If the ultimate pressure value is too high, the gas inside the battery cannot be discharged in time, causing the battery to explode and cause a safety accident. If it is too low, it will lead to premature battery failure and reduce the service life. Therefore, it is necess...

AI Technical Summary

Problems solved by technology

Especially at present, people have simulated the battery under various usage conditions and carried out a series of safety tests around temperature changes, such as hot box, overcharge, acupuncture, short circuit, extrusion, etc., which play an important role in verifying the safety performance of the battery. However, these tests focus on monitoring the temperature change of the battery, but there are few precise and effective methods for the detection of the internal pressure of the battery. Add pressure-sensitive paper during the process, then dissect the battery and take out the pressure-sensitive paper, compare the color of the pressure-sensitive paper with the conventional standard color card, so as to know the pressure and distribution of various parts in the battery

Although information about the internal pressure of the battery can be obtained, this method can only be used for qualitative analysis and has hysteresis; at present, the internal pressure of lithium-ion batteries can only be judged from whether the battery safety valve is opened, which has hysteresis and is not accurate enough sex

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