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Method for detecting safety of lithium ion battery diaphragm

A lithium-ion battery and detection method technology, which is applied in the direction of testing the strength of materials, measuring devices, and strength characteristics using one-time impact force, which can solve the problem of large differences in changing conditions, inability to reflect the thermal melting process of the diaphragm, and the inability to respond to the deformation process of the diaphragm, etc. problem, to achieve the effect of high consistency

Inactive Publication Date: 2020-03-27
CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] CN105445313A discloses a method for detecting thermal stability of a battery diaphragm, which uses a soldering iron above 200°C to pierce the diaphragm laid on a metal conductor plate / glass plate and rests for more than 1s, and evaluates by measuring the diameter of the pierced hole of the diaphragm The thermal stability of the diaphragm; the above method has certain advantages compared with the traditional baking method, and can more accurately reflect the thermal expansion stability of the diaphragm when it is locally overheated; but the above method is a static test method and can only reflect Under the local high temperature, the change of the perforated area of ​​the diaphragm still has a certain gap from the actual situation. It cannot reflect the deformation process of the diaphragm with the steel needle in the initial process of acupuncture, and cannot reflect the thermal melting process of the diaphragm under the condition of small ohmic heat.
[0006] CN109187172A discloses a device and test method for detecting the puncture strength of a diaphragm, which controls the temperature, humidity, puncture speed and displacement of the environment, limits the size of the diaphragm, measures the thickness of the diaphragm, controls the puncture needle to pierce the diaphragm through the driving mechanism, and records it by the sensor Puncture force and take the average value of three measurements to calculate the puncture strength; the above method is complete and rigorous, but it can only reflect the puncture strength of the separator at a specific puncture speed, and the change of the separator under the dual stress of force and heat during the actual short circuit process of the battery The situation is quite different

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  • Method for detecting safety of lithium ion battery diaphragm
  • Method for detecting safety of lithium ion battery diaphragm
  • Method for detecting safety of lithium ion battery diaphragm

Examples

Experimental program
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Effect test

Embodiment 1

[0050] The present embodiment provides a method for detecting the safety of a lithium ion battery diaphragm, comprising the following steps:

[0051] (1) take 3 each of A1, A2, A3, A4 separators, respectively fix the separator in the middle of the positive pole piece and the negative pole piece through the clamp; wherein, the center of the positive pole piece and the negative pole piece There are round holes, and the diameter of the round holes is 8mm;

[0052] (2) vertically penetrate the diaphragm from top to bottom at a rate of 6 mm / s and a constant temperature (60°C, 130°C, and 300°C, respectively), and keep it for a standing time of 10s; wherein, the The steel needle has a built-in heat resistance wire and a temperature probe, the cone angle of the needle tip of the steel needle is 45°-60°, and the diameter of the steel needle is 5 mm.

[0053] The present embodiment is directed to the influence of the type of diaphragm matrix; the test results are averaged, and the dama...

Embodiment 2

[0058] The present embodiment provides a method for detecting the safety of a lithium ion battery diaphragm, comprising the following steps:

[0059] (1) Take three A1 and B1 separators, respectively, fix the separators between the positive pole piece and the negative pole piece through a clamp; wherein, circles are left in the center of the positive pole piece and the negative pole piece hole, the diameter of the circular hole is 8mm;

[0060] (2) The steel needle vertically penetrates the diaphragm from top to bottom at a rate of 0.2 mm / s and a constant temperature (25° C. and 140° C., respectively), and maintains a standing time of 10 s; wherein, the steel needle The needle has a built-in heat resistance wire and a temperature probe, the cone angle of the needle tip of the steel needle is 45°-60°, and the diameter of the steel needle is 5 mm.

[0061] The present embodiment is directed to the influence of the thickness of the diaphragm base; the test results are averaged, ...

Embodiment 3

[0066] The present embodiment provides a method for detecting the safety of a lithium ion battery diaphragm, comprising the following steps:

[0067] (1) Take three A2 and B2 separators, respectively, and fix the separators in the middle of the positive pole piece and the negative pole piece through a clamp; wherein, the center of the positive pole piece and the negative pole piece is left with a circle hole, the diameter of the circular hole is 8mm;

[0068] (2) vertically penetrate the diaphragm from top to bottom at a rate of 30 mm / s and a constant temperature (40°C, 170°C, and 220°C, respectively), and keep it for a standing time of 10s; The steel needle has a built-in heat resistance wire and a temperature probe, the cone angle of the needle tip of the steel needle is 45°-60°, and the diameter of the steel needle is 5 mm.

[0069] This example is aimed at the influence of the thickness of the ceramic coating; the test results are averaged, and the damage of each diaphrag...

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Abstract

The invention relates to the field of high polymer material detection, in particular to a method for detecting the safety of a lithium ion battery diaphragm. The detection method disclosed by the invention comprises the step of enabling a steel needle to penetrate through a diaphragm, wherein the speed of the steel needle penetrating through the diaphragm is 0.01-100mm / s; wherein a thermal resistance wire and a temperature probe are arranged in the steel needle, and the conical angle of the needle tip of the steel needle is 45-60 degrees. The detection method provided by the invention can reflect the deformation process of the diaphragm along with the steel needle in the initial stage of needling, and also can reflect the hot melting process of the diaphragm under the condition of smallerohmic heat; the method has high conformity with the actual condition of the lithium ion battery, and can more accurately reflect the safety performance of the diaphragm under the conditions of internal short circuit, needling and the like of the battery compared with the conventional test method (such as DSC, thermal shrinkage and the like), thereby providing more reliable evidences for the designand material selection of the safety battery.

Description

technical field [0001] The invention relates to the field of polymer material detection, in particular to a method for detecting the safety of a lithium ion battery diaphragm. Background technique [0002] With the popularization and application of lithium-ion batteries in daily life, the safety of lithium-ion batteries has received more and more attention. As an important part of lithium-ion batteries, the separator plays the role of separating the positive and negative electrodes in the battery; if the battery is damaged due to process defects (dust, burr, lithium dendrite, etc.), external force extrusion, acupuncture, etc. If the positive and negative electrodes are short-circuited, the battery may catch fire, explode and other dangerous situations; therefore, as the first valve for battery safety, the safety performance of the diaphragm is crucial to the overall safety performance of the battery. [0003] Acupuncture test is an important test to evaluate the safety beha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/30
CPCG01N3/30G01N2203/0067G01N2203/0075G01N2203/0222G01N2203/0282G01N2203/0676G01N2203/0682G01N2203/0694
Inventor 张海燕赵元宇刘丙学王建涛李翔庞静
Owner CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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