Electrode plate and manufacturing method therefor, electrode assembly, secondary battery, and power consuming device
Lithium replenishing spaces are disposed on a current collection structure, such that the lithium replenishing spaces communicate with an active layer on one side; and the battery is replenished with lithium by using lithium replenishing agents in the lithium replenishing spaces to offset an irreversible lithium consumption in a cycle process, so as to increase the total capacity and the energy density of the battery. According to the present application, due to average weights M A of corresponding active materials in different distribution regions on the active layer, a sum V0 of internal volumes of lithium replenishing spaces corresponding to each of the distribution regions is controlled in a positively correlated manner based on a change in the average weights of the active materials in the different distribution regions.
1. An electrode plate, comprising:
a current collection structure; and
two active layers respectively arranged on two opposite side surfaces of the current collection structure along a thickness direction of the current collection structure, wherein a plurality of lithium replenishing spaces used to communicate with one of the active layers on one side are arranged on the current collection structure, and the lithium replenishing spaces accommodate lithium replenishing agents, wherein
in distribution regions on the active layer communicating with the lithium replenishing spaces, average weights of active materials per unit area of the active layer are denoted as M A , sums of internal volumes of the lithium replenishing spaces that are covered by projections of the distribution regions along the thickness direction of the current collection structure are denoted as V0, and the distribution regions comprise at least a first distribution region and a second distribution region; and
M A in the first distribution region is less than M A in the second distribution region, and corresponding V0 in the first distribution region is less than corresponding V0 in the second distribution region.
2. The electrode plate according to claim 1 , wherein a depth of each of the lithium replenishing spaces is denoted as d, and a thickness of each of the active layers corresponding to positions of the lithium replenishing spaces is denoted as h; and
h in the first distribution region is less than h in the second distribution region, and corresponding d in the first distribution region is less than corresponding d in the second distribution region.
3. The electrode plate according to claim 2 , wherein the depth d of each of the lithium replenishing spaces satisfies the following relationship:
d
≤
C
A
×
M
A
-
C
C
×
M
C
3
8
6
0
×
0
.
5
3
4
×
(
1
×
P
)
×
1
0
0
0
0
,
wherein
C A is an initial lithium intercalation capacity of a negative electrode active material in mAh/g, C C is an initial lithium deintercalation capacity of a positive electrode active material in mAh/g, M C is an average weight of active materials per unit area of a positive electrode in g/cm 2 , and P is a proportion of opening areas of all lithium replenishing spaces per unit area on the current collection structure, wherein, optionally, the proportion P of the opening areas of all the lithium replenishing spaces per unit area satisfies the following relationship:
10%≤P≤50%.
4. The electrode plate according to claim 2 , wherein the depth d of each of the lithium replenishing spaces satisfies the following relationship:
d
≥
(
C
.
E
.
C
-
C
.
E
.
A
)
×
C
A
×
M
A
3
8
6
0
*
0
.
5
3
4
*
(
1
*
P
)
×
1
0
0
0
0
,
wherein
C.E. C is an initial coulombic efficiency of the positive electrode active material, C.E. A is an initial coulombic efficiency of the negative electrode active material, and C A is the initial lithium intercalation capacity of the negative electrode active material in mAh/g;
and/or
wherein the lithium replenishing spaces are arranged at intervals in one of the active lavers on at least one side, and any adjacent two of the lithium replenishing spaces have an equal spacing.
5. The electrode plate according to claim 1 , wherein the current collection structure comprises at least one current collector along the thickness direction of the current collection structure, the lithium replenishing spaces penetrating through at least one of current collectors provided with the active layers.
6. The electrode plate according to claim 5 , wherein the current collection structure comprises two current collectors, the two active layers are respectively disposed on two side surfaces, facing away from each other, of the two current collectors, and the lithium replenishing spaces penetrate through each of the two current collectors, wherein, optionally, the current collection structure further comprises at least one lithium replenishing layer, and the lithium replenishing layer is located between the two current collectors.
7. The electrode plate according to claim 1 , wherein the lithium replenishing spaces are lithium replenishing holes, and the lithium replenishing holes extend into one of the active layers on either side along the thickness direction of the current collection structure.
8. The electrode plate according to claim 1 , wherein the first distribution region extends around a periphery of the second distribution region.
9. A method for manufacturing an electrode plate, comprising the following steps:
step S 100 : providing two single-sided electrode plates, wherein each of the single-sided electrode plates comprises a current collector and an active layer disposed on one side of the current collector;
step S 200 : providing lithium replenishing holes extending into the active layer in the current collector on at least one of the single-sided electrode plates, and controlling average weights M A of active materials per unit area in at least two distribution regions on the active layer and sums V0 of internal volumes of corresponding lithium replenishing holes to satisfy: M A in a first distribution region being less than M A in a second distribution region, and corresponding V0 in the first distribution region being less than corresponding V0 in the second distribution region, wherein the distribution regions comprise the first distribution region and the second distribution region;
step S 300 : depositing lithium replenishing agents in the lithium replenishing holes; and
step S 400 : attaching side surfaces, facing away from the active layers, of the two single-sided electrode plates to each other.
10. The method for manufacturing an electrode plate according to claim 9 , wherein step S 200 comprises:
step S 210 : obtaining thicknesses h of the active layer in different distribution regions;
step S 220 : uniformly providing the plurality of lithium replenishing holes in the current collector; and
step S 230 : controlling depths d of lithium replenishing holes in a projection region of each of the distribution regions on the current collector, such that h in the first distribution region is less than h in the second distribution region, and corresponding d in the first distribution region is less than corresponding d in the second distribution region.
11. The method for manufacturing an electrode plate according to claim 10 , wherein the depth d of each of the lithium replenishing holes satisfies the following relationship:
d
≤
C
A
×
M
A
-
C
C
×
M
C
3
8
6
0
×
0
.
5
3
4
×
(
1
×
P
)
×
1
0
0
0
0
,
wherein
C A is an initial lithium intercalation capacity of a negative electrode active material in mAh/g, C C is an initial lithium deintercalation capacity of a positive electrode active material in mAh/g, M C is an average weight of active materials per unit area of a positive electrode in g/cm 2 , and P is a proportion of hole areas of all lithium replenishing holes per unit area on the current collection structure.
12. The method for manufacturing an electrode plate according to claim 10 , wherein the depth d of each of the lithium replenishing holes satisfies the following relationship:
d
≥
(
C
.
E
.
C
-
C
.
E
.
A
)
×
C
A
×
M
A
3
8
6
0
*
0
.
5
3
4
*
(
1
*
P
)
×
1
0
0
0
0
,
wherein
C.E. C is an initial coulombic efficiency of the positive electrode active material, C.E. A is an initial coulombic efficiency of the negative electrode active material, and C A is the initial lithium intercalation capacity of the negative electrode active material in mAh/g.
13. An electrode assembly, comprising a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate, wherein
the positive electrode plate and/or the negative electrode plate are/is the electrode plate according to claim 1 .
14. A secondary battery, comprising the electrode assembly according to claim 13 .
15. A power consuming device, comprising the secondary battery according to claim 14 .