Energy storage module having extinguisher sheet

1. An energy storage module comprising:

a cover member accommodating a plurality of battery cells in an internal receiving space, the battery cells being arranged in a first direction, each of the battery cells comprising a vent;

a top plate coupled to a top of the cover member and comprising a plurality of ducts respectively corresponding to the vents of the battery cells;

a top cover coupled to a top of the top plate and having a plurality of discharge openings, each of the ducts being aligned with at least one of the discharge openings; and

an extinguisher sheet between the top cover and the top plate, the extinguisher sheet being configured to emit a fire extinguishing agent at a reference temperature,

wherein the extinguisher sheet has openings respectively corresponding to the ducts, and

wherein the openings in the extinguisher sheet extend entirely through the extinguisher sheet in a direction from the top plate toward the top cover to allow a gas to pass from the battery cells entirely through the extinguisher sheet to above the top cover.

2. The energy storage module of claim 1 , wherein the extinguisher sheet extends in the first direction.

3. The energy storage module of claim 1 , further comprising a plurality of insulation spacers respectively between adjacent ones of the battery cells.

4. The energy storage module of claim 3 , wherein the top plate has openings respectively corresponding to the insulation spacers.

5. The energy storage module of claim 4 , wherein the extinguisher sheet is over the openings in top plate and over the insulation spacers.

6. The energy storage module of claim 1 , wherein the extinguisher sheet has an outer cover comprising polyurea or polyurethane and a fire extinguishing agent in a receiving space formed by the outer cover.

7. The energy storage module of claim 6 , wherein the receiving space has a tube shape or a capsule shape.

8. The energy storage module of claim 7 , wherein the fire extinguishing agent comprises halogenated carbon.

9. The energy storage module of claim 1 , wherein the extinguisher sheet comprises a plurality of sheets respectively configured to emit the fire extinguishing agent at different temperatures.

10. The energy storage module of claim 9 , wherein the sheets of the extinguisher sheet are stacked on each other.

11. The energy storage module of claim 1 , further comprising a plurality of the extinguisher sheets.

12. The energy storage module of claim 11 , wherein each of the extinguisher sheets extends in the first direction.

13. The energy storage module of claim 12 , wherein a first one of the extinguisher sheets is between a first electrode terminal of one of the battery cells and the vent of the one of the battery cells, and

wherein a second one of the extinguisher sheets is between a second electrode terminal of the one of the battery cells and the vent of the one of the battery cells.

14. The energy storage module of claim 11 , wherein the extinguisher sheets are spaced from the battery cells by a first distance, and

wherein an upper end of each of the ducts is spaced from the battery cells by a second distance, the first distance being greater than the second distance.

15. The energy storage module of claim 1 , wherein a proportion of the fire extinguishing agent contained in the extinguisher sheet to the total weight of the extinguisher sheet is in a range from 30% to 50%.

16. The energy storage module of claim 1 , wherein the fire extinguishing agent is contained in the extinguisher sheet in an amount of 0.12 g/cm 3 to 0.82 g/cm 3 .

17. The energy storage module of claim 1 , wherein each of the battery cells comprises:

a negative electrode comprising: a negative electrode current collector; a negative electrode active material layer on the negative electrode current collector; and

a negative electrode function layer on the negative electrode active material layer; and

a positive electrode comprising: a positive electrode current collector; and a positive electrode active material layer on the positive electrode current collector,

wherein the negative electrode function layer comprises flake-shaped polyethylene particles, and the positive electrode active material layer comprises a first positive electrode active material comprising at least one composite oxide of lithium and a metal selected from the group consisting of cobalt (Co), manganese (Mn), nickel (Ni), and a combination of these metals and a second positive electrode active material comprising a compound represented by the Chemical Formula (1):

LiaFe1-xMxPO4  (1)

wherein 0.90≤a≤1.8, 0≤x≤0.7, and M is Mn, Co, Ni, or a combination thereof.

18. The energy storage module of claim 17 , wherein the flake-shaped polyethylene particles have an average particle diameter (D50) in a range from 1 μm to 8 μm.

19. The energy storage module of claim 17 , wherein the flake-shaped polyethylene particles have an average particle diameter (D50) in a range from 2 μm to 6 μm.

20. The energy storage module of claim 17 , wherein the flake-shaped polyethylene particles have a thickness in a range from 0 . 2 μm to 4 μm.

21. The energy storage module of claim 17 , wherein the first positive electrode active material and the second positive electrode active material are contained in a weight ratio in a range from 97:3 to 80:20.

22. The energy storage module of claim 1 , wherein the ducts protrude toward the top cover, and

wherein the ducts extend into the respectively corresponding openings in the extinguisher sheet.