Coating slurry, coated separator, preparation method for separator, and battery

2:

• The coating slurry according to claim 1, wherein a glass transition temperature of the first polyimide type adhesive resin is greater than 200° C., and a glass transition temperature of the second polyimide type adhesive resin is greater than 140° C.

3:

• The coating slurry according to claim 1, wherein the solvent is an organic solvent, the polyimide type adhesive resin is a modified polyimide, and the modified polyimide is soluble in the organic solvent.

5:

• The coating slurry according to claim 1, wherein the coating slurry further comprises a coating pore-expanding agent, and a weight proportion of the coating pore-expanding agent in the slurry is 0.05-5 wt %.

6:

• The coating slurry according to claim 5, wherein the coating pore-expanding agent is one or a combination of water, ethanol, polyethylene glycol, and methanol.

7:

• The coating slurry according to claim 6, wherein the coating slurry further comprises ceramic particles, and a weight proportion of the ceramic particles in the slurry is greater than 0 wt % and less than or equal to 5 wt %;
• preferably, the ceramic particles are any one or a combination of alumina, boehmite, silicon oxide, magnesium oxide, titanium oxide, and zirconium oxide.

8:

• The coating slurry according to claim 7, wherein a weight proportion of the solvent in the slurry is 70-95 wt %;
• preferably, the solvent is one or a combination of acetone, N-methylpyrrolidone, and DMAc.

9:

• A coated separator, comprising a substrate and a polymer layer, and the polymer layer is coated on one side or both sides of the substrate;
• wherein the polymer layer comprises at least two functional groups selected from an imide group, heteroaromatic ring, and aromatic ring, and at least one functional group selected from an ester group, ether bond, thioether bond, a ketone group, an amide group, phenolic hydroxyl ether, a methyl group, a methylene group, a trifluoromethyl group, and C—F bond.

10:

• A coated separator, comprising a substrate and a polymer layer, and the polymer layer is coated on one side or both sides of the substrate;
• wherein the polymer layer is formed by coating the coating slurry according to claim 1.

11:

• A coated separator, comprising a substrate and a polymer layer, and the polymer layer is coated on one side or both sides of the substrate;
• wherein the coated separator has a dielectric breakdown voltage of 2.1-5.0 kV, and a dielectric strength is greater than 4.5 kV/mil.

12:

• The coated separator according to claim 9, wherein a surface layer of the polymer layer has a porous structure;
• preferably, the porous structure is a honeycomb-like and dense porous structure.

13:

• The coated separator according to claim 12, wherein the coated separator further comprises ceramic particles, and the ceramic particles are embedded in the polymer layer, with an island-shaped structure;
• preferably, a diameter of the island-shaped structure is 0.5-2 μm.

15:

• A battery, comprising a coated separator, a positive electrode, a negative electrode, and an electrolyte, and the coated separator is the coated separator according to claim 9.