Electrode assembly and secondary battery comprising the same, battery module, battery pack and electrical device

1. An electrode assembly, comprising:

a water-based positive electrode plate; and

a negative electrode plate;

wherein:

the water-based positive electrode plate comprises a positive electrode current collector and a positive electrode film layer located on at least one surface of the positive electrode current collector, and the positive electrode film layer comprises a positive electrode active material;

the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector, and the negative electrode film layer comprises a negative electrode active material;

at least part of surface of the water-based positive electrode plate is provided with a plurality of first micropores, and satisfies:

0.001

%

≤

(

S

1

⁢

2

×

H

1

⁢

2

×

D

1

)

/

(

S

1

⁢

1

×

C

1

×

H

11

)

≤

1

⁢

%

,

wherein H 11 represents a numerical value for the thickness of the water-based positive electrode plate in μm, H 12 represents a numerical value for a depth of the first micropores in μm, S 11 represents a numerical value for the area of the water-based positive electrode plate in m 2 , S 12 represents a numerical value for a total area of the plurality of first micropores in m 2 , C 1 represents a numerical value for a compaction density of the water-based positive electrode plate in g/cc, D 1 represents a numerical value for a volume average particle diameter Dv50 of the positive electrode active material in μm;

at least part of surface of the negative electrode plate is provided with a plurality of second micropores, and satisfies:

0

<

(

S

2

⁢

2

×

H

2

⁢

2

×

D

2

)

/

(

S

2

⁢

1

×

C

2

×

H

2

⁢

1

)

≤

2

.

5

⁢

%

,

wherein H 21 represents thickness of the negative electrode plate in μm, H 22 represents a numerical value for the depth of the second micropores in μm, S 21 represents a numerical value for the area of the negative electrode plate in m 2 , S 22 represents a numerical value for a total area of the plurality of second micropores in m 2 , C 2 represents a numerical value for a compaction density of the negative electrode plate in g/cc, D 2 represents a numerical value for a volume average particle diameter Dv50 of the negative electrode active material in μm.

2. The electrode assembly according to claim 1 , wherein:

0.05

%

≤

(

S

1

⁢

2

×

H

1

⁢

2

×

D

1

)

/

(

S

1

⁢

1

×

C

1

×

H

11

)

≤

0

.

5

⁢

%

.

3. The electrode assembly according to claim 1 , wherein:

0.2

%

≤

(

S

2

⁢

2

×

H

2

⁢

2

×

D

2

)

/

(

S

2

⁢

1

×

C

2

×

H

2

⁢

1

)

≤

2

.

0

⁢

%

.

4. The electrode assembly according to claim 1 , wherein:

0<S 12 /S 11≤2 %; and/or

30%≤H 12 /H 11≤100 %; and/or

C 1 is from 2.0 to 3.0; and/or

D 1 is from 0.5 to 1.5.

5. The electrode assembly according to claim 1 , wherein:

0<S 22 /S 21≤0.2 %; and/or

30%≤H 22 /H 21≤100 %; and/or

C 2 is from 1.2 to 2.0; and/or

D 2 is from 12 to 20.

6. The electrode assembly according to claim 1 , wherein the electrode assembly satisfies: 0.1≤A/B≤1.0, A represents (S 12 ×H 12 ×D 1 )/(S 11 ×C 1 ×H 11 ), and B represents (S 22 ×H 22 ×D 2 )/(S 21 ×C 2 ×H 21 ).

7. The electrode assembly according to claim 1 , wherein the electrode assembly satisfies:

0<S 3 /S 22≤5 %, wherein S 3 represents a numerical value for an overlapping area of the plurality of first micropores and the plurality of second micropores in m 2 .

8. The electrode assembly according to claim 1 , wherein the first micropores satisfy at least one of following (1) to (4):

(1) each of first micropores has regular shape;

(2) each of first micropores has an equivalent diameter of from 1 μm to 200 μm;

(3) a center-to-center distance between adjacent first micropores is from 1 mm to 10 mm; and

(4) the plurality of first micropores are distributed in an array or arrays.

9. The electrode assembly according to claim 1 , wherein the second micropores satisfy at least one of following (1) to (4):

(1) each of second micropores has regular shape;

(2) each of second micropores has an equivalent diameter of from 1 μm to 200 μm;

(3) a center-to-center distance between adjacent second micropores is from 1 mm to 10 mm; and

(4) the plurality of second micropores are distributed in an array or arrays.

10. The electrode assembly according to claim 1 , wherein the positive electrode film layer further comprises one or more of a water-based binder and a conductive agent.

11. The electrode assembly according to claim 10 , wherein the water-based binder comprises a compound mixture of xanthan gum and polyethyleneimine.

12. The electrode assembly according to claim 10 , wherein the water-based binder comprises a compound mixture of acrylonitrile-acrylic acid copolymer and polyethyleneimine.

13. A secondary battery comprising an electrolyte and the electrode assembly according to claim 1 .

14. A battery module comprising the secondary battery according to claim 13 .

15. A battery pack comprising the secondary battery according to claim 13 .

16. An electrical device comprising the secondary battery according to claim 13 .

17. The electrode assembly according to claim 1 , wherein the first micropores satisfy at least one of following (1) to (4):

(1) each of first micropores has irregular shape;

(2) each of first micropores has an equivalent diameter of from 1 μm to 200 μm;

(3) a center-to-center distance between adjacent first micropores is from 1 mm to 10 mm; and

(4) the plurality of first micropores are distributed in an array or arrays.

18. The electrode assembly according to claim 1 , wherein the second micropores satisfy at least one of following (1) to (4):

(1) each of second micropores has irregular shape;

(2) each of second micropores has an equivalent diameter of from 1 μm to 200 μm;

(3) a center-to-center distance between adjacent second micropores is from 1 mm to 10 mm; and

(4) the plurality of second micropores are distributed in an array or arrays.