System and method for checking gas tightness of soft package battery

Abstract

The invention discloses a system and a method for checking the gas tightness of a soft package battery. According to the technical scheme, the checking method comprises the steps of (1) arranging a standard cavity and a to-be-checked sample, and placing the to-be-checked sample in a seal cavity; (2) performing a positive pressure amplification stage: amplifying the amount of gas discharged from aleakage hole of the soft package battery, and applying a pressure to a working cavity; (3) ending the positive pressure amplification stage, and immediately applying the negative pressure to the working cavity; (4) performing a negative pressure inflation stage: keeping that the standard cavity and the working cavity achieve the set negative pressure at the same time, and separating the cavities to ensure that the pressure in each cavity tends to be stable; and (5) performing a checkout stage: if leakage exists in the soft package battery, overflowing the gas through the leakage hole under thepressure of -10 to -99Kpa, increasing the pressure in the working cavity continuously, comparing the pressure of the working cavity with the pressure of the standard cavity, and calculating a leakageamount through a micro-difference sensor.

Description

technical field [0001] The invention relates to the field of air-tightness detection of soft-pack batteries, in particular to a system and method for checking the air-tightness of soft-pack batteries. Background technique [0002] With the rapid development of the lithium battery industry, it is now widely produced and used in all walks of life. According to the needs of the production process, the battery must be sealed after packaging. Due to technical limitations, it is only possible to effectively seal the hard-packed battery. Detection, the sealing detection method for pouch batteries is still in the bottleneck stage. [0003] Defects and deficiencies of existing technical means for sealing inspection of flexible packaging batteries: [0004] ①Air leak detection method: Including internal pressure measurement, external pressure measurement, volume measurement, deformation measurement and other differential pressure comparison methods, none of which can eliminate the in...

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Problems solved by technology

[0004] ①Air leak detection method: Including internal pressure measurement, external pressure measurement, volume measurement, deformation measurement and other differential pressure comparison methods, none of which can eliminate the influence of air pressure on the shape of flexible packaging and the change in volume

For example: during the inflation or exhaust process of the flexible packaging test, due to the change of the external pressure, the volume of the flexible packaging will change, and when the product is defective, the volume and pressure in the packaging will change, so whether the pressure detection or volume detection is used It is not obvious and cannot be applied in batches to the batch, efficient and stable detection of flexible packaging batteries on the production line

[0005] ②Halogen detection method, VOC detection: through the analysis of volatile gas, liquid specific molecules and elements to determine whether there is leakage, this method cannot be used because there will be residues in the cavity and inside the instrument

[0006] ③ Helium detection method: the detection cost of this method is too high, which is not conducive to the economic benefits of the enterprise

[0008] Although this detection process has high detection accuracy and saves the use of helium to a large extent, the cost of using helium to detect the air tightness of pouch batteries is still high, and other detection methods on the market can only be compared. Well-adapted to hard-pack batteries, there has been no more accurate and fast testing method for air-tightness testing of soft-pack batteries

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