A test method for continuous withstand voltage of thin films

Abstract

The invention discloses a method for testing continuous withstand voltage of a film, which comprises the following steps: (1) placing the film to be tested on a rewinding and unwinding device to be unwound; (2) setting a booster pump provided by a central control system The pressure range is between 0 and 5MPa; (3) Set the heating rod to work or not through the central control system; (4) Set the intermittent travel speed, boost rate, breakdown current upper limit and / or lower limit; (5) Turn on the test circuit switch, carry out program boosting, and start the test; (6) When the withstand voltage tester automatically powers off and the buzzer sounds, end the test and record the displayed voltage in this area at this time; ( 7) Continuously test different regions of the film to be tested through the winding and unwinding device to obtain the breakdown voltage data of the film. With this method, the pressure and withstand voltage of the separator in the battery can be better simulated, the battery production can be predicted, the waste of raw materials in the battery production process can be reduced, and the yield rate can be improved.

Description

technical field [0001] The invention relates to the field of thin film testing equipment, in particular to a method for testing continuous withstand voltage of thin films. Background technique [0002] With the promotion of electric vehicles, the power battery market is expanding day by day, and higher requirements are put forward for the electrical performance and safety performance of lithium-ion batteries. As one of the key materials of lithium-ion batteries, the diaphragm plays an important role in the electrical performance and safety performance of lithium-ion batteries. [0003] Generally, during the production process of lithium batteries, the battery manufacturer will assemble the positive and negative electrodes of the battery and the diaphragm material, and then load a certain voltage on the positive and negative electrodes of the battery to test the short circuit rate of the lithium battery; in this test, if the resistance of the diaphragm If the voltage value i...

AI Technical Summary

Problems solved by technology

As mentioned in CN 207366690 U, a method for testing the breakdown voltage of a single-point fixed area, although the value of the breakdown voltage of the diaphragm in a certain area can be accurately measured, most of the positions cannot be tested, and it is easy to ignore the existence of The weak point of the breakdown voltage, the sampling has a large randomness, and the test range is limited; and the parallelism of the electrode plate is poor, which may easily lead to a low degree of bonding between the film to be tested and the electrode plate, and the measured data may not necessarily be the separator. The lowest withstand voltage value, so there is a large error in the test results

CN208818795U mentions a kind of test method of isolation film breakdown voltage, adopts conductive rod sliding to do electrode to carry out the test of breakdown voltage, although can test continuously, but in the process of conductive rod movement, there are jitter and parallelism problems, the pressure between two electrodes And the temperature is also uncontrollable, the test stability is poor

Moreover, at present, the soft-pack lithium-ion battery will go through the process of hot and cold pressing during assembly, and there is a certain tension in the diaphragm inside the winding core. Under this pressure and temperature conditions, the withstand voltage characteristics of the diaphragm will change to a certain extent.

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