WO2025100353A1 - Battery cell - Google Patents

Abstract

A battery cell (100) comprises: battery elements (110); an exterior film (140) wound around the battery elements (110); and a spacer (150) at least partially positioned between the battery element (110) and the exterior film (140).

Description

Battery Cell

The present invention relates to a battery cell.

In recent years, various types of battery cells have been developed. A battery cell includes a battery element and an exterior material that seals the battery element.

Patent Document 1 describes a battery module. The battery module includes a plurality of unit cells, and an upper retaining member and a lower retaining member located on either side of the unit cells in the stacking direction of the unit cells. An adhesive is bonded between the unit cell in the uppermost layer of the unit cells and the upper retaining member, and another adhesive is bonded between the unit cell in the lowermost layer of the unit cells and the lower retaining member.

Patent Document 2 describes a film-cased battery. The film-cased battery is equipped with a film-casing material. A solid barrier material is provided on the inner surface of the end of the film-casing material from which the positive and negative terminals are pulled out.

Patent Document 3 describes a lithium ion secondary battery. The lithium ion secondary battery comprises a battery element, a battery can that houses the battery element, and a sealing plate provided at the upper opening of the battery can. A foamed resin sheet is disposed between the lower part of the battery element and the battery can. Another foamed resin sheet is disposed between the upper part of the battery element and the sealing plate.

JP 2019-053892 A International Publication No. 2018/021550 JP 2002-231297 A

In a battery cell, an exterior film may be wrapped around the battery element. Certain functions may be required of a battery cell with an exterior film wrapped around the battery element.

One object of the present invention is to improve the performance of a battery cell. Other objects of the present invention will become apparent from the description of this specification.

One aspect of the present invention is as follows.
1. A battery element;
An exterior film wrapped around the battery element;
a spacer located at least partially between the battery element and the exterior film;
A battery cell comprising:
2. A terminal electrically connected to the battery element is further provided,
the battery element has a shape having a longitudinal direction and a lateral direction perpendicular to a direction from a side where the battery element is located to a side where the terminal is located,
1. The battery cell according to 1., wherein at least a portion of the spacer is located on at least one of both sides of the battery element in the longitudinal direction.
3. The battery cell according to 1. or 2., wherein the battery element and the exterior film are physically joined to each other via the spacer.
4. The battery cell according to any one of 1. to 3., wherein the battery element and the exterior film are thermally coupled to each other via the spacer.
5. The battery cell according to any one of 1. to 4., wherein a plurality of the battery elements are physically joined to one another via the spacer.
6. The battery cell according to any one of 1. to 5., wherein the spacer at least partially includes an adhesive.

The above aspect of the present invention can improve the functionality of the battery cell.

FIG. 2 is a perspective view of a battery cell according to an embodiment. FIG. 2 is a side view of a battery cell according to an embodiment with an exterior film removed. FIG. 2 is a schematic cross-sectional view of a virtual plane α shown in FIG. 1 .

Below, an embodiment of the present invention will be described with reference to the drawings. In all drawings, similar components are given similar reference symbols and descriptions will be omitted as appropriate.

FIG. 1 is a perspective view of a battery cell 100 according to an embodiment. FIG. 2 is a side view of the battery cell 100 according to an embodiment with the exterior film 140 removed. FIG. 3 is a schematic cross-sectional view of the imaginary plane α shown in FIG. 1.

In each figure, the X direction, the Y direction, and the Z direction are shown for the purpose of explanation. The X direction indicates the front-rear direction of the battery cell 100. The Y direction is a direction perpendicular to the X direction. The Y direction indicates the left-right direction of the battery cell 100. The Z direction is a direction perpendicular to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 100. The arrows indicating the X direction, the arrows indicating the Y direction, and the arrows indicating the Z direction indicate the rear, right, and up directions of the battery cell 100, respectively. In FIG. 2, the white circle with an X indicating the Y direction indicates that the arrow indicating the Y direction extends from the front to the back of the paper. In FIG. 3, the white circle with an X indicating the X direction indicates that the arrow indicating the X direction extends from the front to the back of the paper. The relationship between the X direction, the Y direction, and the Z direction and the front-rear direction, left-right direction, and up-down direction of the battery cell 100 is not limited to the example of the explanation in the embodiment.

Hereinafter, as necessary, the side indicated by the arrow indicating the X direction will be referred to as the +X side, and the side opposite the side indicated by the arrow indicating the X direction will be referred to as the -X side. Hereinafter, as necessary, the side indicated by the arrow indicating the Y direction will be referred to as the +Y side, and the side opposite the side indicated by the arrow indicating the Y direction will be referred to as the -Y side. Hereinafter, as necessary, the side indicated by the arrow indicating the Z direction will be referred to as the +Z side, and the side opposite the side indicated by the arrow indicating the Z direction will be referred to as the -Z side.

The imaginary plane α shown in Figs. 1 and 3 is a plane perpendicular to the X direction at approximately the center of the battery cell 100 in the X direction according to the embodiment. For the sake of explanation, the dimensional ratio of the battery cell 100 in the Y direction to the Z direction shown in Fig. 3 is greater than the dimensional ratio of the battery cell 100 in the Y direction to the Z direction shown in Fig. 1.

As shown in Figures 1 to 3, the battery cell 100 according to the embodiment includes a plurality of battery elements 110, a pair of terminals 120, a pair of lid members 130, an exterior film 140, and a spacer 150.

In the example shown in FIG. 3, multiple battery elements 110 overlap each other in the Y direction. Hereinafter, as necessary, multiple battery elements 110 overlapping each other in the Y direction are collectively referred to as a laminate 110G. Each battery element 110 has an approximately rectangular parallelepiped shape. Specifically, when viewed from the X direction, each battery element 110 has a shape having a longitudinal direction and a transverse direction perpendicular to the X direction. When viewed from the X direction, the longitudinal direction of each battery element 110 is oriented in the Z direction. When viewed from the X direction, the transverse direction of each battery element 110 is oriented in the Y direction. In the examples shown in FIG. 1 and FIG. 3, when viewed from the X direction, the laminate 110G has a shape having a longitudinal direction and a transverse direction perpendicular to the X direction, similar to each battery element 110. The number of battery elements 110 included in the battery cell 100 is not limited to the example shown in FIG. 3. For example, the battery cell 100 may include only one battery element 110, two battery elements 110, or four or more battery elements 110.

As shown in FIG. 3, each battery element 110 has a plurality of positive electrodes 112, a plurality of negative electrodes 114, and a separator 116. In each battery element 110, the plurality of positive electrodes 112 and the plurality of negative electrodes 114 are arranged alternately in the Y direction. The area perpendicular to the Y direction of each negative electrode 114 is larger than the area perpendicular to the Y direction of each positive electrode 112. In the example shown in FIG. 3, the dimension in the Z direction of each negative electrode 114 is larger than the dimension in the Z direction of each positive electrode 112. As shown in FIG. 3, when viewed from the X direction, the separator 116 includes a zigzag portion 116a and a surrounding portion 116b. When viewed from the X direction, the zigzag portion 116a is alternately folded at the folded portion on the +Z side of the zigzag portion 116a and the folded portion on the -Z side of the zigzag portion 116a. When viewed from the X direction, the zigzag portion 116a separates the positive electrodes 112 and negative electrodes 114 adjacent in the Y direction, with the folded portion on the +Z side of the zigzag portion 116a covering the end on the +Z side of the positive electrode 112 and the folded portion on the -Z side of the zigzag portion 116a covering the end on the -Z side of the negative electrode 114. When viewed from the X direction, the surrounding portion 116b surrounds the positive electrodes 112 and negative electrodes 114 that are alternately arranged in the Y direction and the zigzag portion 116a.

The structure of the separator 116 is not limited to the structure shown in FIG. 3. For example, the separator 116 may not include the surrounding portion 116b and may include only the zigzag portion 116a. Alternatively, the battery element 110 may include a plurality of separators 116 having a substantially sheet shape perpendicular to the Y direction, instead of the separator 116 shown in FIG. 3. When the battery element 110 includes a plurality of separators 116 having a substantially sheet shape perpendicular to the Y direction, the plurality of positive electrodes 112, the plurality of negative electrodes 114, and the plurality of separators 116 are stacked in the Y direction with each separator 116 separating the positive electrodes 112 and the negative electrodes 114 adjacent to each other in the Y direction. Alternatively, the positive electrodes 112, the negative electrodes 114, and the separators 116 may be wound so that the separators 116 are disposed between the positive electrodes 112 and the negative electrodes 114. In one example, the positive electrode 112, the negative electrode 114, and the separator 116 are wound with one of both sides of the positive electrode 112 and the negative electrode 114 covered by the separator 116. In another example, a laminate including a plurality of unit laminates including the positive electrode 112, the separator 116, and the negative electrode 114 in this order may be wound. However, the winding structure of the positive electrode 112, the negative electrode 114, and the separator 116 is not limited to these examples.

As shown in FIG. 2, a pair of terminals 120 are located on both sides of the laminate 110G in the X direction. The -X side terminal 120 and the positive electrode 112 of the laminate 110G are electrically connected to each other via the drawn-out positive electrode collector 112a. Therefore, in the embodiment, the -X side terminal 120 is a positive electrode terminal. The drawn-out positive electrode collector 112a is drawn out from the laminate 110G toward the -X side. In one example, the drawn-out positive electrode collector 112a is integrated with the positive electrode collector constituting the positive electrode 112. The +X side terminal 120 and the negative electrode 114 of the laminate 110G are electrically connected to each other via the drawn-out negative electrode collector 114a. Therefore, in the embodiment, the +X side terminal 120 is a negative electrode terminal. The drawn-out negative electrode collector 114a is drawn out from the laminate 110G toward the +X side. In one example, the drawn-out negative electrode current collector 114a is integrated with the negative electrode current collector that constitutes the negative electrode 114. The terminal 120 on the -X side may be the negative electrode terminal, and the terminal 120 on the +X side may be the positive electrode terminal.

As shown in FIG. 2, a pair of lid materials 130 are located on both sides of the laminate 110G in the X direction. Each lid material 130 is, for example, a resin body. As shown in FIG. 1, when viewed from the X direction, each lid material 130 has a substantially rectangular shape having a pair of short sides parallel to the Y direction and a pair of long sides parallel to the Z direction. The -X side terminal 120 at least partially protrudes toward the -X side from the -X side surface of the -X side lid material 130 when the -X side lid material 130 covers the -X side end surface of the laminate 110G. The +X side terminal 120 at least partially protrudes toward the +X side from the +X side surface of the +X side lid material 130 when the +X side lid material 130 covers the +X side end surface of the laminate 110G.

In the embodiment, the exterior film 140 is a flexible laminate film. As shown in FIG. 1 and FIG. 3, the exterior film 140 has a wrapped portion 142 and a pulled-out portion 144. The wrapped portion 142 is wrapped around the X direction of the laminate 110G and the pair of lid materials 130. The outer peripheral surface around the X direction of the -X side lid material 130 and the inner peripheral surface around the X direction of the -X side end of the wrapped portion 142 are joined to each other by a joining method such as heat fusion. Thus, a sealing portion is formed by the -X side lid material 130 and the -X side end of the wrapped portion 142. The outer peripheral surface around the X direction of the +X side lid material 130 and the inner peripheral surface around the X direction of the +X side end of the wrapped portion 142 are joined to each other by a joining method such as heat fusion. Thus, a sealing portion is formed by the +X side lid material 130 and the +X side end of the wrapped portion 142. As shown in FIG. 3, the drawn-out portion 144 includes a first drawn-out portion 144a and a second drawn-out portion 144b. The first drawn-out portion 144a is drawn out from one end of the wound portion 142 in the X direction, and the second drawn-out portion 144b is drawn out from the other end of the wound portion 142 in the X direction. The surfaces of the first drawn-out portion 144a and the second drawn-out portion 144b that contact each other are joined to each other by a joining method such as heat fusion. Thus, a sealing portion is formed by the first drawn-out portion 144a and the second drawn-out portion 144b. In the example shown in FIG. 1 and FIG. 3, when viewed from the X direction, the drawn-out portion 144 is drawn out from a corner on the +Y side and +Z side of the laminate 110G and is bent toward the outer surface on the +Z side of the wound portion 142. However, the way in which the drawn-out portion 144 is drawn out is not limited to the example shown in FIG. 1 and FIG. 3.

In the battery cell 100 according to the embodiment, the pair of lid materials 130 and the exterior film 140 seal the space surrounded by the wrapped portion 142 between the pair of lid materials 130. The laminate 110G is located inside the space sealed by the pair of lid materials 130 and the exterior film 140. The battery cell 100 according to the embodiment contains an electrolyte inside the space sealed by the pair of lid materials 130 and the exterior film 140. However, the battery cell 100 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in the portion corresponding to the separator 116. An all-solid-state battery does not contain an electrolyte. Hereinafter, unless otherwise specified, the battery cell 100 will be described as a battery cell containing an electrolyte.

As shown in Figures 2 and 3, the spacer 150 is located between the -Z outer surface of the laminate 110G and the +Z inner surface of the portion of the wrapped portion 142 that covers the -Z outer surface of the laminate 110G. Thus, the spacer 150 is at least partially located between the laminate 110G and the exterior film 140. Hereinafter, as necessary, the -Z outer surface of the laminate 110G will be referred to as the outer bottom surface of the laminate 110G, the portion of the wrapped portion 142 that covers the outer bottom surface of the laminate 110G will be referred to as the bottom of the wrapped portion 142, and the +Z surface of the bottom of the wrapped portion 142 will be referred to as the inner bottom surface of the wrapped portion 142.

In an embodiment, the battery cell 100 can be placed on a plate not shown in FIGS. 1 to 3 with the bottom of the winding portion 142 facing downward. When the battery cell 100 is placed on a plate with the bottom of the winding portion 142 facing downward, multiple battery cells 100 can be stacked on top of each other in the Y direction. Thus, multiple battery cells 100 stacked on top of each other in the Y direction can be electrically connected to each other in series, parallel, or a combination of series and parallel to form a battery module.

In the embodiment, the spacer 150 at least partially contains an adhesive. Specifically, the spacer 150 is a cured adhesive. The adhesive is cured, for example, by drying. The spacer 150 is adhered to both the outer bottom surface of the laminate 110G and the inner bottom surface of the wound portion 142. Therefore, the outer bottom surface of the laminate 110G and the inner bottom surface of the wound portion 142 are physically joined to each other via the spacer 150. Therefore, it is possible to suppress the mutual movement of the laminate 110G and the wound portion 142 due to an impact from outside the battery cell 100. Furthermore, in the example shown in FIG. 3, the spacer 150 extends continuously along the outer bottom surface of the laminate 110G. Therefore, the multiple battery elements 110 included in the laminate 110G are physically joined to each other via the spacer 150. Therefore, it is possible to suppress the mutual movement of the multiple battery elements 110 due to an impact from outside the battery cell 100. Therefore, it is possible to improve the function of the battery cell 100.

The -Z side surface of the spacer 150 according to the embodiment can be formed to be approximately flat. When the -Z side surface of the spacer 150 is approximately flat, the battery cell 100 can be stably placed on a plate not shown in FIGS. 1 to 3 with the bottom of the wound portion 142 facing downward, compared to when the spacer 150 is not provided. Furthermore, compared to when the outer bottom surface of the laminate 110G and the inner bottom surface of the wound portion 142 are in direct contact with each other without the spacer 150 being provided, the load on the bottom of the wound portion 142 due to the weight of the laminate 110G can be more easily and uniformly distributed, and damage to the bottom of the wound portion 142 due to the weight of the laminate 110G can be suppressed. Therefore, the function of the battery cell 100 can be improved by the spacer 150.

The spacer 150 according to the embodiment may have thermal conductivity. In one example, the spacer 150 may at least partially include a thermally conductive adhesive. When the spacer 150 has thermal conductivity, the laminate 110G and the wound portion 142 can be thermally coupled to each other via the spacer 150. When the laminate 110G and the wound portion 142 are thermally coupled to each other via the spacer 150, the heat generated from each battery element 110 can be more easily released toward the bottom of the wound portion 142 via the spacer 150, compared to when the spacer 150 is not provided. For example, when the battery cell 100 is placed on a plate via a thermally conductive material such as thermal glue with the bottom of the wound portion 142 facing downward, the heat generated from each battery element 110 can be more easily released to the plate via the spacer 150, the bottom of the wound portion 142, and the thermally conductive material. Therefore, the function of the battery cell 100 can be improved by the spacer 150.

The spacer 150 according to the embodiment may function as a reinforcing member that improves the strength of each battery element 110 included in the laminate 110G. When the spacer 150 functions as a reinforcing member, the strength of each battery element 110 can be improved compared to when the spacer 150 is not provided. Therefore, the function of the battery cell 100 can be improved by the spacer 150.

The spacer 150 does not have to be an adhesive. For example, the spacer 150 may be a rigid plate such as a resin plate. Even if the spacer 150 is a rigid plate, the battery cell 100 can be stably placed on a plate not shown in Figures 1 to 3 with the bottom of the wound portion 142 facing downward, and damage to the bottom of the wound portion 142 due to the weight of the stack 110G can be suppressed, compared to when the spacer 150 is not provided.

The position where the spacer 150 is arranged is not limited to the example shown in Figures 1 to 3. The spacer 150 may be provided not only between the outer bottom surface of the laminate 110G and the inner bottom surface of the wound portion 142, but also in other parts between the outer peripheral surface around the X direction of the laminate 110G and the inner peripheral surface around the X direction of the wound portion 142. For example, when viewed from the X direction, the spacer 150 may be located on at least one of both sides in the longitudinal direction of the laminate 110G. In other words, the spacer 150 may be located on at least one of the -Z side and +Z side of the laminate 110G.

Next, an example of a method for manufacturing the battery cell 100 will be described. In the following example, the spacer 150 will be described as being a liquid or gel adhesive in an uncured state.

First, a plurality of battery elements 110 are formed. Next, a plurality of battery elements 110 are stacked to form a laminate 110G. Next, the drawn-out positive electrode collector 112a and the -X side terminal 120 are electrically connected to each other, and the -X side surface of the laminate 110G is covered with the -X side lid material 130. The order of the electrical connection of the drawn-out positive electrode collector 112a and the -X side terminal 120 and the covering of the -X side surface of the laminate 110G with the -X side lid material 130 is not particularly limited. In addition, the drawn-out negative electrode collector 114a and the +X side terminal 120 are electrically connected to each other, and the +X side surface of the laminate 110G is covered with the +X side lid material 130. The order of the electrical connection of the drawn-out negative electrode collector 114a and the +X side terminal 120 and the covering of the +X side surface of the laminate 110G with the +X side lid material 130 is not particularly limited.

Next, uncured spacer 150 is applied to the outer bottom surface of laminate 110G. Next, while spacer 150 is in an uncured state, wrapped portion 142 is wrapped around laminate 110G and the pair of lid members 130 in the X direction. Next, spacer 150 is dried and hardened, and the outer bottom surface of laminate 110G and the inner bottom surface of wrapped portion 142 are physically joined to each other via spacer 150.

Next, the outer peripheral surface around the X direction of the -X side lid material 130 and the inner peripheral surface around the X direction of the -X side end of the exterior film 140 are joined together by heat fusion. Also, the outer peripheral surface around the X direction of the +X side lid material 130 and the inner peripheral surface around the X direction of the +X side end of the exterior film 140 are joined together by heat fusion. Next, electrolyte is injected into the space surrounded by the winding portion 142 between the pair of lid materials 130 through the gap between the first pull-out portion 144a and the second pull-out portion 144b. Next, the space surrounded by the winding portion 142 between the pair of lid materials 130 is evacuated through the gap between the first pull-out portion 144a and the second pull-out portion 144b. Next, the surfaces of the first pull-out portion 144a and the second pull-out portion 144b that contact each other are joined together by heat fusion.

The battery cell 100 is manufactured using the method described above.

The above describes the embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

For example, in the embodiment, the terminal 120 electrically connected to the positive electrode 112 and the terminal 120 electrically connected to the negative electrode 114 are located on both sides of the battery element 110 in the X direction. However, both the terminal 120 electrically connected to the positive electrode 112 and the terminal 120 electrically connected to the negative electrode 114 may be located on the same side of the battery element 110, either the +X side or the -X side.

This application claims priority based on Japanese Patent Application No. 2023-189102, filed November 6, 2023, the entire disclosure of which is incorporated herein by reference.

100 battery cell, 110 battery element, 110G laminate, 112 positive electrode, 112a drawn positive electrode current collector, 114 negative electrode, 114a drawn negative electrode current collector, 116 separator, 116a zigzag portion, 116b surrounding portion, 120 terminal, 130 lid material, 140 exterior film, 142 wrapped portion, 144 drawn portion, 144a first drawn portion, 144b second drawn portion, 150 spacer

Claims (6)

A battery element;
An exterior film wrapped around the battery element;
a spacer located at least partially between the battery element and the exterior film;
A battery cell comprising: a terminal electrically connected to the battery element;
the battery element has a shape having a longitudinal direction and a lateral direction perpendicular to a direction from a side where the battery element is located to a side where the terminal is located,
The battery cell according to claim 1 , wherein at least a portion of the spacer is located on at least one of both sides of the battery element in the longitudinal direction. The battery cell according to claim 1 or 2, wherein the battery element and the exterior film are physically joined to each other via the spacer. The battery cell according to any one of claims 1 to 3, wherein the battery element and the exterior film are thermally bonded to each other via the spacer. The battery cell according to any one of claims 1 to 4, wherein the battery elements are physically joined to each other via the spacer. The battery cell according to any one of claims 1 to 5, wherein the spacer at least partially comprises an adhesive.

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