Air tightness detecting system used for lithium battery and detecting method thereof

Abstract

The present invention discloses an air tightness detecting system used for the lithium battery, wherein the air tightness detecting system comprises the following components: a pressurizing and pressure relieving mechanism, a sealing mechanism, a detecting sealing chamber, a downstream precise flow leak detector and a reference volume chamber. The sealing chamber comprises a base of the tested workpiece, a first sealing gasket, an upper sealing cover and a second sealing gasket which is placed on an appropriate position of the upper sealing cover. Thereby the detecting system is divided into an inner chamber of the workpiece and an outer chamber of the workpiece. The inner chamber of the workpiece and the outer chamber of the workpiece are provided with a controllable valve channel for connecting or switching-off with the pressurizing and pressure relieving mechanism and the downstream precise flow leak detector. The reference volume chamber is a closed container and is connected with the inner chamber of the workpiece through the downstream flow lead detector. The invention simultaneously discloses a method for detecting the detecting system. The air tightness detecting system of the invention can detect the little leakage generated in the manufacturing process of the lithium battery effectively, quickly and reliably.

Description

technical field [0001] The invention relates to a detection system for the airtightness of a lithium ion battery, and the involved lithium ion battery can be square, cylindrical or other shapes. Background technique [0002] The air tightness detection of lithium-ion batteries is an important part of monitoring the battery welding and assembly process, and is one of the main production processes of lithium-ion battery manufacturing. In order to ensure product quality, the sampling rate of air tightness testing is required to be 100%. [0003] There are currently two methods for airtightness detection of lithium-ion batteries: immersion bubble detection and differential pressure airtightness detection: [0004] Immersion bubble detection method: immerse the battery in liquid, pressurize the inside of the battery to a certain pressure with pure nitrogen and keep the pressure; then detect the air leakage of the battery by visually observing the air bubbles generated when the a...

AI Technical Summary

Problems solved by technology

[0004] Immersion bubble detection method: immerse the battery in liquid, pressurize the inside of the battery to a certain pressure with pure nitrogen and maintain the pressure; then detect the air leakage of the battery by visually observing the air bubbles generated when the air leaks outside the battery. This detection method is simple It is clear that the detection cost is low, but its shortcomings are: (1) the reliability of detection is highly dependent on the operator's visual inspection, and its human factors are strong, and it is easy to miss detection in the continuous operation process; (2) detection automation The degree is low, and the detection speed is slow; (3) the internal pressure of the battery is close to the tolerance limit of the workpiece during detection, which constitutes additional constraints on the mechanical strength of the structural design of the workpiece; (4) the detection of consumables (nitrogen) causes waste of resources; Pressurized gas injection may have a negative impact on subsequent processes

The main disadvantages of this method are: (1) the internal pressure of the battery is close to the bearing limit of the workpiece during detection, which constitutes additional constraints on the mechanical strength of the structural design of the workpiece; (2) the detection of consumables (nitrogen) causes waste of resources; Internal pressurized gas injection, which may have a negative impact on subsequent processes

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