Energy storage module

1. An energy storage module comprising:

a plurality of battery cells arranged in a first direction such that long side surfaces of adjacent ones of the battery cells face one another, each of the battery cells comprising a vent;

a plurality of insulation spacers, each adjacent pair of the battery cells having at least one of the insulation spaces between the long side surfaces of the battery cells, each of the insulation spacers comprising a heat-insulating first sheet and a plurality of flame-retardant second sheets respectively adhered to opposite surfaces of the first sheet by an adhesion member;

a cover member comprising an internal receiving space configured to accommodate the battery cells and the insulation spacers;

a top plate coupled to a top of the cover member, the top plate comprising ducts respectively corresponding to the vents of the battery cells and fluid guide protrusions around fire extinguishing agent openings respectively corresponding to the insulation spacers, the fluid guide protrusions extending above the respectively corresponding insulation spacers;

a top cover coupled to a top of the top plate and having discharge openings respectively corresponding to the ducts; 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 temperature exceeding a reference temperature,

wherein the long side surfaces of adjacent battery cells are spaced apart from each other by a first distance,

wherein a thickness of each of the insulation spacers is less than 50% of the first distance, and

wherein edges of the fire extinguishing agent openings are spaced apart from the corresponding insulation spacer such that, when the fire extinguishing agent is emitted from the extinguisher sheet, the fire extinguishing agent fills spaces between the insulation spacers and the battery cells through the fire extinguishing agent openings.

2. The energy storage module of claim 1 , wherein the first sheet comprises ceramic paper, and the second sheets comprise MICA paper.

3. The energy storage module of claim 2 , wherein the first sheet comprises a ceramic fiber comprising an alkaline earth metal.

4. The energy storage module of claim 1 , wherein each of the insulation spacers has a width-direction size less than twice a height-direction size thereof, and

wherein the first sheet is adhered to the second sheets at opposite ends thereof by the adhesion member.

5. The energy storage module of claim 4 , wherein the insulation spacers further comprise an edge part comprising a plastic material, and

wherein the edge part is formed at peripheral edges of the first and second sheets by insert molding.

6. The energy storage module of claim 5 , wherein the edge part has a width in a range from 3 mm to 6 mm.

7. The energy storage module of claim 4 , wherein one surface of each of the insulation spacers faces the long side surface of one of the battery cells, and the other surface of each of the insulation spacers faces the long side surface of another one of the battery cells.

8. The energy storage module of claim 4 , wherein the first sheet and the second sheets are spaced apart from each other at central portions thereof to form air passages.

9. The energy storage module of claim 8 , wherein the first sheet is spaced apart from each of the second sheets by the adhesion member.

10. The energy storage module of claim 1 , wherein a width-direction size of the insulation spacers is greater than twice a height-direction size thereof, and

wherein the first sheet and the second sheets are adhered to each other by the adhesion member applied to a region adjacent top and bottom ends of each of the first sheet and the second sheets.

11. The energy storage module of claim 10 , wherein one surface of each of the insulation spacers faces the long side surfaces of two of the battery cells, and the other surface of each of the insulation spacers faces the long side surfaces of another two of the battery cells.

12. 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 Mg, Co, Ni or combinations thereof.

13. The energy storage module of claim 12 , wherein the flake-shaped polyethylene particles have an average particle diameter (D50) in a range from 1 μm to 8 μm.

14. The energy storage module of claim 12 , wherein the flake-shaped polyethylene particles have an average particle diameter (D50) in a range from 2 μm to 6 μm.

15. The energy storage module of claim 12 , wherein the flake-shaped polyethylene particles have a thickness in a range from 0.2 μm to 4 μm.

16. The energy storage module of claim 12 , 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.

17. The energy storage module of claim 1 , wherein the insulation spacer is not between the corresponding fluid guide protrusions in the first direction.