Secondary battery head cover assembly, secondary battery including the same and assembling method thereof

1. A secondary battery head cover assembly, comprising a head cover and an insulation structure, wherein the insulation structure comprises a top connection sheet and two naked battery core insulation sheets, and the two naked battery core insulation sheets are connected to two long sides of the top connection sheet, respectively,

an electrode pole is provided on the head cover, and an electrode pole through hole is provided at a position on the top connection sheet corresponding to the electrode pole, the top connection sheet is located below the head cover and is connected to the head cover,

wherein, the head cover is further provided with a liquid injection hole, and the top connection sheet is further provided with a liquid injection through hole,

wherein, the liquid injection through hole is provided correspondingly below the liquid injection hole.

2. The secondary battery head cover assembly according to claim 1 , wherein, at least one connecting hole for connecting to the head cover is provided on the top connection sheet, at least one connecting piece is provided on a lower surface of the head cover, and the connecting piece is fitted with and connected to the connecting hole.

3. The secondary battery head cover assembly according to claim 2 , wherein, the connecting piece is a riveting piece or an engaging piece.

4. The secondary battery head cover assembly according to claim 1 , wherein, a lower plastic is provided on the head cover, and the top connection sheet is fixed with the lower plastic by hot melting.

5. The secondary battery head cover assembly according to claim 1 , wherein, the top connection sheet and the two naked battery core insulation sheets are integrated as a whole.

6. The secondary battery head cover assembly according to claim 1 , wherein, the head cover is further provided with an explosion-proof valve, and the top connection sheet is further provided with an explosion-proof valve air hole,

wherein, the explosion-proof valve air hole is provided correspondingly below the explosion-proof valve.

7. The secondary battery head cover assembly according to claim 1 , wherein, the head cover is further provided with a reversing sheet, and the top connection sheet is further provided with a reversing sheet air hole,

wherein, the reversing sheet air hole is provided correspondingly below the reversing sheet.

8. The secondary battery head cover assembly according to claim 1 , wherein, the electrode pole passes through the electrode pole through hole.

9. A secondary battery, comprising a naked battery core and the secondary battery head cover assembly according to claim 1 , wherein

the naked battery core is located below the top connection sheet, and the two naked battery core insulation sheets cover two main side surfaces of the naked battery core.

10. The secondary battery according to claim 9 , wherein, the two naked battery core insulation sheets comprise:

two main insulation regions directly connected with the top connection sheet, respectively;

the two main insulation regions cover the two main side surfaces of the naked battery core, respectively.

11. The secondary battery according to claim 10 , wherein, the two main insulation regions completely cover the two main side surfaces of the naked battery core, respectively.

12. The secondary battery according to claim 10 , wherein, one of the two naked battery core insulation sheets comprises:

a side insulation region formed by extending the main insulation region outward along two lateral sides perpendicular to the long side, and a bottom insulation region formed by extending the main insulation region outward along a side away from the top connection sheet, wherein the bottom insulation region is provided with an electrolyte permeation hole;

the side insulation region covers a narrow side surface of the naked battery core, the bottom insulation region covers a bottom surface of the naked battery core, the side insulation regions located on different naked battery core insulation sheets which cover the same side of the naked battery core are connected with each other, and the two bottom insulation regions are also connected with each other.

13. The secondary battery according to claim 10 , further comprising a chassis plate, wherein the chassis plate is fixedly attached to a surface of one of the bottom insulation regions.

14. The secondary battery according to claim 1 , wherein, the two naked battery core insulation sheets have consistent structures.

15. The secondary battery according to claim 10 , wherein, crease lines are provided at a junction between the main insulation region and the side insulation region, and at a junction of a junctional region between the main insulation region and the bottom insulation region.

16. The secondary battery according to claim 10 , wherein:

the side insulation regions located on different naked battery core insulation sheets which cover the same side of the naked battery core are connected with each other by hot melting,

and/or

the two bottom insulation regions are connected with each other by hot melting.

17. A method for assembling the secondary battery according to claim 9 , comprising steps as follows:

connecting the top connection sheet to the head cover;

welding the naked battery core and the head cover; and

wrapping the naked battery core by the naked battery core insulation sheet.