The present invention relates to a battery.
In recent years, non-aqueous electrolyte secondary batteries, in particular, lithium ion secondary batteries have been developed. The non-aqueous electrolyte secondary battery has a laminate including a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators. The plurality of positive electrodes and the plurality of negative electrodes are alternately stacked, and the plurality of separators separate the positive electrodes and the negative electrodes from each other.
The laminate may swell under specific conditions. Patent Document 1 discloses that the laminate swells in overcharge. Patent Document 1 discloses that pressure is applied between the positive electrode and the negative electrode in overcharge in order to suppress swelling of the laminate.
[Patent Document 1] Japanese Unexamined Patent Publication No. 2002-117904
The present inventor has found that the positive electrode and the negative electrode have a possibility of being short-circuited to each other by expanding the laminate. The present inventors have studied conditions for preventing the occurrence of the short circuit between the short circuit and the positive electrode even if the laminate swells.
An object of the present invention is to suppress the possibility of a short circuit between the positive electrode and the negative electrode even if the laminate swells. Other objects of the present invention are clear from the following description of embodiments.
According to an aspect of the present invention, there is provided a battery including:
a laminate that includes a plurality of first electrodes, a plurality of second electrodes which have polarities different from the plurality of first electrodes and are alternately arranged with the plurality of first electrodes, and a plurality of separators that respectively separate the first electrodes and the second electrodes from each other; and
a plurality of first tabs that respectively protrude from the plurality of first electrodes and are bundled together,
wherein the plurality of first electrodes includes a primary first-electrode, a secondary first-electrode, and a tertiary first-electrode,
the primary first-electrode is located between the secondary first-electrode and the tertiary first-electrode,
the first tab for the primary first-electrode, the first tab for the secondary first-electrode, and the first tab for the tertiary first-electrode are connected to each other at a first position of an equal distance from the secondary first-electrode and the tertiary first-electrode,
the plurality of second electrodes includes a primary second-electrode adjacent to the primary first-electrode,
the plurality of separators includes a first separator that separates the primary first-electrode and the primary second-electrode from each other,
in a case where the laminate does not swell in a thickness direction of the laminate,
the laminate has a thickness T0 from the secondary first-electrode to the tertiary first-electrode,
the first position is spaced from an end portion of the first separator on the first position side by a distance L0 in a direction perpendicular to the thickness direction of the laminate,
the end portion of the first separator on the first position side protrudes toward the first position from an end portion of the primary second-electrode on the first position side, by a distance G in the direction perpendicular to the thickness direction of the laminate, and
the laminate is designed such that, even if the laminate swells in the thickness direction of the laminate, a thickness of the laminate from the secondary first-electrode to the tertiary first-electrode is smaller than 4×{(T0/2)2+L02−(L0−G)2}1/2.
According to another aspect of the present invention, there is provided a battery including:
a plurality of laminates, each including a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators;
a plurality of exterior materials that respectively accommodate the plurality of the laminates and are stacked together;
a plurality of spacers that separate the adjacent exterior materials from each other; and
a member that integrally fixes the plurality of the laminates and the plurality of spacers,
wherein the plurality of exterior materials includes a first exterior material, a second exterior material, and a third exterior material in order,
the plurality of spacers includes a first spacer that separates the first exterior material and the second exterior material from each other and a second spacer that separates the second exterior material and the third exterior material from each other,
the first spacer includes a first portion overlapping the first exterior material and the second exterior material and a second portion protruding toward the second spacer from the first portion of the first spacer,
the second spacer includes a first portion overlapping the second exterior material and the third exterior material and a second portion protruding toward the first spacer from the first portion of the second spacer, and
the second portion of the first spacer and the second portion of the second spacer face each other.
According to the above aspect of the present invention, it is possible to reduce a possibility of a short circuit between the positive electrode and the negative electrode even if the laminate swells.
The above-described object and other objects, features, and advantages will be further clarified by the preferred embodiments described below and the following drawings attached thereto.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the similar components are denoted by the similar reference numerals, and description thereof will not be repeated.
The battery 10 will be described with reference to
In the embodiment, the first electrode 110 is a positive electrode, and the second electrode 120 is a negative electrode. In the example illustrated in
In another example, the first electrode 110 and the second electrode 120 may be a negative electrode and a positive electrode, respectively. As is clear from the description of the embodiment, the configuration according to the embodiment is not limited to an example in which the first electrode 110 and the second electrode 120 are a positive electrode and a negative electrode, respectively. The configuration in the embodiment may be applied to an example in which the first electrode 110 and the second electrode 120 are a negative electrode and a positive electrode, respectively.
The plurality of first electrodes 110 include a first electrode 110a (primary first-electrode), a first electrode 110b (secondary first-electrode), and a first electrode 110c (tertiary first-electrode). The first electrode 110a is located between the first electrode 110b and the first electrode 110c. In the example illustrated in
The first tab 112 (first tab 112a) of the first electrode 110a, the first tab 112 (first tab 112b) of the first electrode 110b, and the first tab 112 (first tab 112c) of the first electrode 110c are connected to each other at the first position P1. The first position P1 is of an equal distance from the first electrode 110b and the first electrode 110c.
The plurality of second electrodes 120 include a second electrode 120a (primary second electrode). The second electrode 120a is adjacent to the first electrode 110a.
The plurality of separators 130 include a separator 130a (first separator). The separator 130a separates the first electrode 110a and the second electrode 120a from each other.
In
As illustrated in
The laminate 100 is designed such that, even if the laminate 100 swells in the thickness direction of the laminate 100, the thickness of the laminate 100 from the first electrode 110b to the first electrode 110c is smaller than 4×{(T0/2)2+L02−(L0−G)2}1/2.
The present inventor has found the followings. If the thickness of the laminate 100 from the first electrode 110b to the first electrode 110c is suppressed to be within the above-described range, a possibility of a short circuit between the first electrode 110 and the second electrode 120, in particular, between the first electrode 110a and the second electrode 120a (that is, the first electrode 110a and the second electrode 120a located at the substantially center of the laminate 100) is reduced.
With reference to
The laminate 100 swells from a thickness T0 (
The following expression (1) is established based on Pythagorean theorem.
Δ2=L02+(T0/2)2=L12+(T1/2)2 (1)
Specifically, the distance between the end portion of the first electrode 110b and the first position P1 is constant (Δ in
The condition for reducing the possibility of contact between the first tab 112a of the first electrode 110a and the second electrode 120a may be as represented by the following expression (2).
L
0
−L
1
<G (2)
Specifically, if the first position P1 moves in the direction toward the laminate 100, the first tab 112a of the first electrode 110a is bent and comes into contact with the second electrode 120a as illustrated in
The following expression (3) is derived from the expressions (1) and (2).
T
1<4×{(T0/2)2+L02−(L0−G)2}1/2 (3)
The expression (3) means that the possibility of a short circuit between the first electrode 110a and the second electrode 120a is reduced by suppressing the thickness of the laminate 100 from the first electrode 110b to the first electrode 110c to be smaller than 4×{(T0/2)2+L02−(L0−G)2}1/2.
The battery 10 includes a plurality of first tabs 112 and a plurality of second tabs 122. As described with reference to
The laminate 100 has a first surface 102, a second surface 104, a third surface 106, and a fourth surface 108. The first surface 102 and the second surface 104 are located on sides opposite to each other in the thickness direction of the laminate 100. The third surface 106 is between the first surface 102 and the second surface 104 and is closer to the plurality of first tabs 112 than to the plurality of second tabs 122. The fourth surface 108 is between the first surface 102 and the second surface 104 and is closer to the plurality of second tabs 122 than to the plurality of first tabs 112.
The battery 10 includes a member 300. The member 300 is attached to the laminate 100. In the example illustrated in
Since the member 300 covers the plurality of first tabs 112 side of the laminate 100, it is possible to restrict swelling of the plurality of first tabs 112 side of the laminate 100.
In addition, since the member 300 exposes the plurality of second tabs 122 side of the laminate 100, it is possible to reduce the member 300 attached to the laminate 100. Specifically, as described with reference to
The member 300 covers the laminate 100 over the entire circumference including the first surface 102, the second surface 104, the third surface 106, and the fourth surface 108.
Since the member 300 covers the laminate 100 over the entire circumference, it is possible to restrict swelling of the laminate 100.
The battery 10 includes an exterior material 200. The exterior material 200 accommodates the laminate 100 (for example,
The battery 10 includes an accommodation member 400. The accommodation member 400 defines a space 402. The accommodation member 400 accommodates the exterior material 200 in the space 402.
The accommodation member 400 restricts the swelling of the laminate 100 (exterior material 200) in the thickness direction of the laminate 100 (exterior material 200). Specifically, the length of the space 402 in the thickness direction of the laminate 100 (the exterior material 200) is designed such that the thickness of the laminate 100 is suppressed to be within the above-described range even if the laminate 100 (exterior material 200) swells to the maximum in the space 402.
In the example illustrated in
The battery 10 includes a plurality of exterior materials 200, a plurality of spacers 510, a member 520, a cover 532, and a cover 534. The plurality of exterior materials 200 accommodate the plurality of laminates 100, respectively (for example,
In the example illustrated in
The plurality of exterior materials 200 include a first exterior material 200a, a second exterior material 200b, and a third exterior material 200c. The first exterior material 200a, the second exterior material 200b, and the third exterior material 200c are arranged in order.
The plurality of spacers 510 include a first spacer 510a and a second spacer 510b. The first spacer 510a separates the first exterior material 200a and the second exterior material 200b from each other. The second spacer 510b separates the second exterior material 200b and the third exterior material 200c from each other.
The first spacer 510a includes a first portion 512 and a second portion 514. The first portion 512 of the first spacer 510a overlaps the first exterior material 200a and the second exterior material 200b. The second portion 514 of the first spacer 510a protrudes toward the second spacer 510b from the first portion 512 of the first spacer 510a. In the example illustrated in
The second spacer 510b includes a first portion 512 and a second portion 514. The first portion 512 of the second spacer 510b overlaps the second exterior material 200b and the third exterior material 200c. The second portion 514 of the second spacer 510b protrudes toward the first spacer 510a from the first portion 512 of the second spacer 510b. In the example illustrated in
The second portion 514 of the first spacer 510a and the second portion 514 of the second spacer 510b face each other.
In the example illustrated in
In the example illustrated in
In addition, in the example illustrated in
In the example illustrated in
Also in the example illustrated in
Hitherto, the embodiment of the present invention has been described with reference to the drawings, and various configurations other than the above description can be employed.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2017/037781 | 10/19/2017 | WO | 00 |