GB/T 36363-2018Polyolefin separator for lithium-ion battery (English PDF)

6.2 Standard environment for specimen conditioning and testing

6.2.1 Specimen status conditioning

The specimen shall be conditioned in accordance with the following conditions as specified in GB/T 2918-1998.

a) Temperature. (23 ± 2) °C;

b) Relative humidity. (50 ± 10) %;

c) Duration. not less than 4 h.

6.2.2 Standard environmental conditions of the test

The standard environmental conditions for the test are as follows.

a) Temperature. (23 ± 2) °C;

b) Relative humidity. (50 ± 10) %.

6.3 Appearance

The pinhole is detected with a magnifying glass or optical microscope magnified 10 times. The winding unevenness of the diaphragm roll end face is measured by a gauge having a resolution of not less than 0.5 mm. The rest of the appearance items are visually tested.

6.4 Size

6.4.1 Thickness deviation

It is performed with reference to the provisions of GB/T 6672-2001. The resolution of the thickness gauge shall be no more than 0.1 µm, the position of the measured thickness is as shown in Figure 1. The equidistant tests in the lateral direction forms one group of not less than 3 points, and a group is tested every 200 mm in the longitudinal direction. A total of 5 groups are tested.

6.5.1 Tensile strength, elongation at break

It is performed in accordance with the provisions of GB/T 1040.3-2006, use the type 2 specimen with a width of (15±0.1) mm, the initial distance between the clamps is (100±5) mm, the test speed is (250±10) mm/min.

6.5.2 Heat shrinkage rate

6.5.2.1 Test equipment

The test equipment shall meet the following requirements.

a) Blast-type incubator. accuracy is ± 1 °C;

b) Stainless steel plate;

c) Length measuring instrument. resolution is 0.1 mm or 0.5 mm.

6.5.2.2 Specimen

Cut 3 pieces of square diaphragm of 100 mm × 100 mm in the longitudinal direction of the diaphragm roll, make one edge of the diaphragm is parallel to the longitudinal edge of the diaphragm when cutting it, with a maximum deviation angle not exceeding 5°, make the longitudinal and transverse markings. If the diaphragm width is < 100 mm, the sampling size is 100 mm × diaphragm width.

6.5.2.3 Test procedure

Place the stainless steel plate and two pieces of quantitative filter paper in the middle of the oven, control the temperature so that the stainless steel plate and filter paper reach (90 ± 1) °C or (120 ± 1) °C.

In accordance with the longitudinal and lateral directions of the diaphragm as shown in Figure 3, based on the actual needs, use the length measuring instrument of the corresponding resolution to respectively measure the longitudinal and transverse direction length of the specimen, extend the diaphragm and place it on one of the qualitative filter paper on the stainless steel plate at the middle of the blower type thermostat. After completing it, use another piece of quantitative filter paper to press it, close the thermostat door, start time calculation, maintain for 2 h ± 12 min at 90 °C or for 1 h ± 6 min at 120°C.

7.3.2 Exit-factory inspection

The exit-factory inspection items are. appearance, size, physical properties. The exit-factory inspections shall be carried out batch by batch.

7.4 Decision rules

Appearance and sizes are determined in accordance with the sampling plan of 7.2.

If one of the appearance and size is unqualified, the roll is a non-conforming product.

If there are unqualified items in the physical performance and electrical performance results, the sample shall be re-doubled from the original batch and the unqualified items shall be re-examined. If the physical property is still unqualified, the physical properties of the batch of diaphragms are unqualified; if the re-inspection results are still unqualified, the electrical properties of the batch of diaphragms are unqualified.

In the type inspection, if the appearance, size, physical properties and electrical properties are all qualified, the batch is judged to be qualified.

During the exit-factory inspection, if the appearance, size, physical properties are all qualified, then the batch is qualified.

8.1 Packaging

The end faces of each roll of the diaphragm are protected by a gasket, and after being positioned, they are packed in a plastic film bag and then placed in the box.

The packaging shall ensure that the diaphragm is not damaged during transportation and storage, and is not contaminated by foreign objects. Packaging materials shall be easy to recycle. […]