CN117477114A

CN117477114A - Battery cell

Info

Publication number: CN117477114A
Application number: CN202310896591.4A
Authority: CN
Inventors: 大冈爱佳
Original assignee: Aesc Japan
Current assignee: Aesc Japan
Priority date: 2022-07-28
Filing date: 2023-07-20
Publication date: 2024-01-30
Also published as: JP2024043689A

Abstract

The invention provides a battery cell. The battery cell includes: a battery element; a front cover for covering one end of the battery element in a given direction; and at least a portion of the exterior film being wound around the battery element in a given direction. The outer film has rounded corners along the battery element at least 1 corner of the battery element around a given direction.

Description

Battery cell

Technical Field

The present invention relates to a battery cell.

Background

In recent years, various structures of battery cells such as lithium ion secondary battery cells have been developed. For example, the battery cells described in patent documents 1 to 3 include battery elements, 2 covers, and an exterior film. The 2 covers cover both ends of the battery element in the longitudinal direction. The exterior film is wound around the battery element in the longitudinal direction.

Prior art literature

Patent literature

Patent document 1: international publication No. 2021/157731

Patent document 2: JP patent publication 2011-108623

Patent document 3: JP-A2011-108626

(mode 1)

For example, in the battery cells described in patent documents 1 to 3, the outer coating film may not be sufficiently strongly wound around the battery element. In this case, the volume of the battery cell may not be sufficiently reduced. Therefore, the volume energy density of the battery cell may not be sufficiently high.

An example of the object of embodiment 1 of the present invention is to increase the volumetric energy density of a battery cell. Other objects of embodiment 1 of the present invention will be apparent from the description of the present specification.

(mode 2)

For example, in the battery cell described in patent document 1, the exterior film includes: a winding part wound around the battery element; and 2 lead-out portions led out from the winding portion. The 2 lead-out portions are joined to each other to form a sealing portion. However, in this structure, the seal portion needs to be bent in order to suppress the protrusion of the seal portion.

An example of the object of embodiment 2 of the present invention is to suppress protrusion of a sealing portion of an exterior film. Other objects of embodiment 2 of the present invention will be apparent from the description of the present specification.

(mode 3)

For example, in the battery cell described in patent document 1, when the exterior film is wound around the lid member, the end portion of the exterior film is exposed. When the end of the outer coating film is exposed, it becomes difficult to suppress a short circuit of the outer coating film through a conductor such as a conductive sheet contained in the outer coating film.

An example of the object of embodiment 3 of the present invention is to suppress exposure of the end portion of the exterior film. Other objects of embodiment 3 of the present invention will be apparent from the description of the present specification.

(mode 4)

For example, in the battery cell described in patent document 2, wrinkles may be formed in the exterior film due to deformation of the shape of the exterior film. However, if the wrinkles of the exterior film exist around the battery element of the exterior film, the wrinkles may be transferred to the battery element. As a result, the characteristics of the battery cells may be affected by the wrinkles.

An example of the object of embodiment 4 of the present invention is to stabilize the characteristics of the battery cell. Other objects of embodiment 4 of the present invention will be apparent from the description of the present specification.

(mode 5)

A certain strength may be obtained in the longitudinal direction of the battery cell. However, for example, in the battery cell described in patent document 3, it is difficult to ensure the strength of the battery cell in the longitudinal direction of the battery cell in the battery element cell.

An example of the object of embodiment 5 of the present invention is to ensure the strength of the battery cell in the longitudinal direction. Other objects of embodiment 5 of the present invention will be apparent from the description of the present specification.

Disclosure of Invention

Embodiment 1 of the present invention is as follows.

1.1A battery cell includes: a battery element; a cover member covering one end of the battery element in a predetermined direction; and an exterior film at least a portion of which is wound around the given direction at the battery element, the exterior film having rounded corners along the battery element at least 1 corner of the battery element around the given direction.

1.2 on the basis of the battery cell of 1.1, corners of the cover, which are juxtaposed in the given direction with the at least 1 corners of the battery element, are rounded.

1.3 in the case of the battery cell according to 1.1 or 1.2, a folding line is provided at least at 1 corner of the battery element in the exterior film around the given direction.

1.4 the battery cell according to any one of 1.1 to 1.3, further comprising: and a cover member covering the other end of the battery element in the predetermined direction.

Embodiment 2 of the present invention is as follows.

2.1A battery cell includes: a battery element; a cover member that covers an end portion of the battery element; and an exterior film having a winding portion wound around the battery element and a lead-out portion led out from the winding portion, at least a part of the winding portion and at least a part of the lead-out portion being joined to each other.

2.2 the battery cell according to 2.1, wherein the junction of the winding portion and the lead portion overlaps at least a part of a surface of the battery element facing in a predetermined direction.

2.3 the battery cell according to 2.1, wherein the battery element includes: a given length in the 1 st direction between the end portion and the other end portion on the opposite side of the end portion; a width in a 2 nd direction orthogonal to the 1 st direction; and a thickness in a 3 rd direction shorter than the width and orthogonal to the 1 st and 2 nd directions, wherein a joint portion of the winding portion and the lead portion overlaps at least a part of a surface of the battery element substantially orthogonal to the 3 rd direction.

2.4 the battery cell according to 2.1, wherein the battery element includes: a given length in the 1 st direction between the end portion and the other end portion on the opposite side of the end portion; a width in a 2 nd direction orthogonal to the 1 st direction; and a thickness in a 3 rd direction shorter than the width and orthogonal to the 1 st and 2 nd directions, wherein a joint portion of the winding portion and the lead portion overlaps at least a part of a surface of the battery element substantially orthogonal to the 2 nd direction.

2.5 the battery cell according to any one of 2.1 to 2.4, wherein the joint portion between the winding portion and the lead portion is located at an arbitrary portion other than the lower portion around the battery element.

Embodiment 3 of the present invention is as follows.

3.1A battery cell includes: a battery element; a tab electrically connected to the battery element; a cover member that covers an end portion of the battery element and guides out the tab; and an exterior film, at least a portion of which is wound around the battery element, at least a portion of the cover covering at least a portion of an end of the exterior film.

3.2 in addition to the battery cell described in 3.1, at least a portion of the cover covers at least a portion of the outer peripheral surface of the exterior film.

3.3 the battery cell according to 3.1 or 3.2, further comprising: and a further cover member that covers the other end portion on the opposite side of the end portion of the battery element.

Embodiment 4 of the present invention is as follows.

4.1A battery cell includes: a battery element; a tab electrically connected to the battery element via a collecting portion of a current collector led out from the battery element; a cover member that covers one end of the battery element and guides out the tab; and an outer coating film, at least a part of which is wound around the battery element, wherein the outer coating film has wrinkles around the collecting portion of the current collector.

4.2 the battery cell according to 4.1, wherein the cover has a size larger than the size of the battery element when viewed from the lead-out direction of the tab.

4.3 the battery cell according to 4.1, wherein the cover has a size smaller than the size of the battery element when viewed from the lead-out direction of the tab.

Embodiment 5 of the present invention is as follows.

5.1A battery cell includes: a battery element; a cover member that covers an end portion of the battery element in the longitudinal direction; an exterior film at least a part of which is wound around the battery element in the longitudinal direction; and a reinforcement body provided along the longitudinal direction of the battery element.

5.2 the battery cell according to 5.1, wherein one end of the reinforcing body in the longitudinal direction is joined to the lid member.

5.3 in addition to the battery cell described in 5.1 or 5.2, at least a part of the reinforcing body has a lead-out portion of the exterior film that is bent a plurality of times.

ADVANTAGEOUS EFFECTS OF INVENTION

According to embodiment 1 of the present invention, the volumetric energy density of the battery cell can be increased.

According to embodiment 2 of the present invention, the protrusion of the sealing portion of the exterior film can be suppressed.

According to embodiment 3 of the present invention, the exposure of the end portion of the exterior film can be suppressed.

According to embodiment 4 of the present invention, the characteristics of the battery cell can be stabilized.

According to embodiment 5 of the present invention, the strength of the battery cell in the longitudinal direction can be ensured.

Drawings

Fig. 1 is a front perspective view of a battery cell according to embodiment 1.

Fig. 2 is an enlarged front perspective view of a part of the battery cell according to embodiment 1.

Fig. 3 is a right side view of the battery cell according to embodiment 1.

Fig. 4 is a schematic view of section A-A of fig. 3.

Fig. 5 is a diagram for explaining example 1 of the method for manufacturing a battery cell according to embodiment 1.

Fig. 6 is a diagram for explaining example 2 of the method for manufacturing a battery cell according to embodiment 1.

Fig. 7 is a right side view of a battery cell according to embodiment 2.

Fig. 8 is a schematic view of section B-B of fig. 7.

Fig. 9 is a diagram for explaining an example of a method for manufacturing a battery cell according to embodiment 2.

Fig. 10 is a cross-sectional view of a battery cell according to a modification.

Fig. 11 is a front perspective view of a battery cell according to embodiment 3.

Fig. 12 is a front enlarged perspective view of a part of a battery cell according to embodiment 3.

Fig. 13 is a right side view of a battery cell according to embodiment 3.

Fig. 14 is a schematic view of section C-C of fig. 12.

Fig. 15 is a diagram showing a modification of fig. 14.

Fig. 16 is a front perspective view of a battery cell according to embodiment 4.

Fig. 17 is a front enlarged perspective view of a part of a battery cell according to embodiment 4.

Fig. 18 is a right side view of a battery cell according to embodiment 4.

Fig. 19 is a schematic view of section D-D of fig. 18.

Fig. 20 is a diagram for explaining example 1 of a method for manufacturing a battery cell according to embodiment 4.

Fig. 21 is a diagram for explaining example 2 of a method for manufacturing a battery cell according to embodiment 4.

Fig. 22 is a front perspective view of a battery cell according to a modification.

Fig. 23 is a front perspective view of a battery cell according to embodiment 5.

Fig. 24 is a front enlarged perspective view of a part of a battery cell according to embodiment 5.

Fig. 25 is a right side view of a battery cell according to embodiment 5.

Fig. 26 is a diagram showing a battery cell according to a modification.

Detailed Description

(embodiment 1)

Embodiment 1 of the present invention will be described below with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof is omitted.

Fig. 1 is a front perspective view of a battery cell 10A according to embodiment 1. Fig. 2 is a front enlarged perspective view of a part of the battery cell 10A according to embodiment 1. Fig. 3 is a right side view of battery cell 10A according to embodiment 1. Fig. 4 is a schematic view of section A-A of fig. 3. Fig. 3 illustrates a state of transmitting the exterior film 300A for the sake of explanation. In fig. 4, a drawing of a lead portion 304A described later is omitted.

In the drawings, for the sake of explanation, X direction, Y direction, and Z direction are labeled. The X direction represents the front-rear direction of the battery cell 10A. The Y direction is orthogonal to the X direction. The Y direction represents the left-right direction of the battery cell 10A. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 10A. The direction pointed by the arrow representing the X direction, the direction pointed by the arrow representing the Y direction, and the direction pointed by the arrow representing the Z direction are the rear direction, the left direction, and the upper direction, respectively. The relationship among the X direction, Y direction, Z direction, front-rear direction, left-right direction, and up-down direction of the battery cell 10A is not limited to this example.

The white circle with X indicating the X direction, Y direction, or Z direction indicates a direction from the near side of the paper surface to the depth, and is directed by an arrow indicating the direction.

The battery cell 10A includes a battery element 100A, a positive electrode tab (tab) 110A, a negative electrode tab 120A, a front cover 210A, a rear cover 220A, and an exterior film 300A. The exterior film 300A has a winding portion 302A and a lead-out portion 304A.

The battery element 100A has a substantially rectangular parallelepiped shape. The longitudinal direction of battery element 100A is substantially parallel to the X direction. The length of the battery element 100A in the X direction is not limited to the following, but is, for example, 300mm to 500mm, and preferably 450 mm. The short side direction of battery element 100A is substantially parallel to the Z direction. The length of battery element 100A in the Z direction is not limited to the following, but is, for example, 90mm to 130mm, preferably 120 mm. The thickness direction of battery element 100A is substantially parallel to the Y direction. The thickness of the battery element 100A in the Y direction is not limited to the following, and is, for example, 20mm to 50mm, preferably 45 mm. However, the shape of battery element 100A is not limited to this example.

As shown in fig. 4, battery element 100A has at least 1 positive electrode 102A, at least 1 negative electrode 104A, and at least 1 separator 106A. In the example shown in fig. 4, the battery element 100A schematically has 1 positive electrode 102A, 2 negative electrodes 104A, and 4 separators 106A. The number of positive electrodes 102A, the number of negative electrodes 104A, and the number of separators 106A are not limited to the example shown in fig. 4.

The positive electrodes 102A and the negative electrodes 104A are alternately stacked in the Y direction. The area of the negative electrode 104A in the direction perpendicular to the Y direction is larger than the area of the positive electrode 102A in the direction perpendicular to the Y direction. In the example shown in fig. 4, the length of the negative electrode 104A in the Z direction is longer than the length of the positive electrode 102A in the Z direction.

In addition to separators 106A located at both ends of battery element 100A in the Y direction, separators 106A are located between positive electrode 102A and negative electrode 104A adjacent in the Y direction. In the example shown in fig. 4, a separator 106A is provided on the left side of the anode 104A located on the leftmost side. Further, a separator 106A is provided on the right side of the anode 104A located on the rightmost side. The area of the separator 106A in the direction perpendicular to the Y direction is larger than the area of the negative electrode 104A in the direction perpendicular to the Y direction. In the example shown in fig. 4, the length of the separator 106A in the Z direction is longer than the length of the negative electrode 104A in the Z direction.

As shown in fig. 3, positive electrode tab 110A is disposed in front of battery element 100A. The rear end portion of the positive electrode tab 110A is electrically connected to the positive electrode collector 102 aA. The positive electrode current collector 102aA is led forward from the positive electrode 102A. Thus, the positive electrode tab 110A is electrically connected to the plurality of positive electrodes 102A.

As shown in fig. 3, negative electrode tab 120A is disposed behind battery element 100A. The distal end portion of the negative electrode tab 120A is electrically connected to the negative electrode collector 104 aA. The negative electrode current collector 104aA is drawn rearward from the negative electrode 104A. Thus, the negative electrode tab 120A is electrically connected to the plurality of negative electrodes 104A.

The front cover 210A covers the front end of the battery element 100A. The front cover 210A contains, for example, resin, metal, or the like. The front end of the positive electrode tab 110A protrudes from the front surface of the front cover 210A. The front cover 210A has a substantially rectangular shape with rounded corners around 4 corners in the X direction as viewed from the front. The long side direction of the front cover 210A is substantially parallel to the Z direction, and the short side direction of the front cover 210A is substantially parallel to the Y direction, as viewed from the front. The angle 4 around the X direction of the front cover 210A is aligned with the angle 4 around the X direction of the battery element 100A in the X direction.

The rear cover 220A covers the rear end of the battery element 100A. The rear cover 220A contains, for example, resin, metal, or the like. The rear end of the negative electrode tab 120A protrudes from the rear surface of the rear cover 220A. The rear cover 220A has a substantially rectangular shape with rounded corners around 4 corners in the X direction as viewed from the rear. The long side direction of the rear cover 220A is substantially parallel to the Z direction, and the short side direction of the rear cover 220A is substantially parallel to the Y direction, as viewed from the rear. The angle 4 around the X direction of the rear cover 220A is aligned with the angle 4 around the X direction of the battery element 100A in the X direction.

As shown in fig. 1 and 2, the winding portion 302A has a substantially tubular shape that is open both forward and rearward. The front cover 210A is disposed inside the opening in front of the winding portion 302A. The rear cover 220A is disposed inside the opening at the rear of the winding portion 302A. The winding portion 302A is wound around the battery element 100A, the front cover 210A, and the rear cover 220A around the X direction for 1 week. As a result, as shown in fig. 4, front cover 210A, rear cover 220A, and winding portion 302A form accommodating space 500A that accommodates battery element 100A. In the housing space 500A, an electrolyte solution, not shown, is housed together with the battery element 100A. In addition, the manner of winding the battery element 100A of the winding portion 302A is not limited to the above-described example.

An outer peripheral surface of the front cover 210A around the X direction and an inner peripheral surface of the opening in front of the wound portion 302A around the X direction are joined to each other by, for example, thermal welding. Thereby, a front seal 510A is formed in front of the accommodation space 500A.

An outer peripheral surface of the rear cover 220A around the X direction and an inner peripheral surface of the opening at the rear of the wound portion 302A around the X direction are joined to each other by, for example, thermal welding. Thereby, the rear seal 520A is formed behind the accommodation space 500A.

As shown in fig. 1 and 2, the lead-out portion 304A is led out from the corner of the upper left side of the battery element 100A of the winding portion 302A, as viewed from the front. Specifically, as shown in fig. 2, the lead-out portion 304A includes a 1 st lead-out portion 304aA and a 2 nd lead-out portion 304bA. The 1 st lead-out portion 304aA is led out from one of both ends of the winding portion 302A around the circumferential direction in the X-direction. The 2 nd lead-out portion 304bA is led out from the other of the two ends of the winding portion 302A around the circumferential direction in the X direction. The 1 st lead-out portion 304aA and the 2 nd lead-out portion 304bA are joined to each other by, for example, thermal fusion. Thus, the side seal 530A is formed on the upper left side of the housing space 500A as viewed from the front. The lead portion 304A is bent along the upper surface of the battery element 100A. The lead portion 304A may not be bent. The shape of the bending of the lead portion 304A is not limited to the shape according to embodiment 1.

As shown in fig. 4, the winding portion 302A has rounded corners along the battery element 100A at least 1 corner of the battery element 100A around the X direction. Specifically, the Z-direction ends of the separator 106A located at the Y-direction ends of the battery element 100A are bent toward the Y-direction center of the battery element 100A. The winding portion 302A is wound along the curvature of both end portions of these separators 106A in the Z direction at the 4 angle around the X direction of the battery element 100A. For example, a case where the Z-direction both ends of the separator 106A located at both ends in the Y-direction of the battery element 100A are not bent toward the center in the Y-direction of the battery element 100A and are substantially parallel to the Z-direction will be studied. Alternatively, a case where the 4-angle around the X direction of the battery element 100A of the winding portion 302A is not wound along the bends of both ends of the separators 106A in the Z direction but becomes substantially right angle will be studied. In embodiment 1, the volume of the battery cell 10A can be reduced as compared with those cases. Therefore, in embodiment 1, the volumetric energy density of the battery cell 10A can be improved as compared with the case described above.

As shown in fig. 1 and 2, in embodiment 1, the 4 corners of the front cover 210A, which are aligned with the 4 corners of the battery element 100A around the X direction, have rounded corners. Therefore, the wound portion 302A can be more easily rounded at the 4 corners around the X direction of the battery element 100A than in the case where the 4 corners of the front cover 210A are not rounded. Similarly, the 4 corners of the rear cover 220A, which are aligned with the 4 corners of the battery element 100A around the X direction, are rounded. Therefore, the wound portion 302A can be more easily rounded at the 4 corners around the X direction of the battery element 100A than in the case where the 4 corners of the rear cover 220A are not rounded.

The above-described 4 corners of the front cover 210A may not have rounded corners. Alternatively, only a part of the above-described 4 corners of the front cover 210A may be rounded. Likewise, the above-described 4 corners of the rear cover 220A may not have rounded corners. Alternatively, only a part of the above-described 4 corners of the rear cover 220A may be rounded.

The radius of curvature of the circle of the wound portion 302A at the upper left corner of the battery element 100A, that is, the corner where the lead-out portion 304A of the battery element 100A around the X direction is led out, is sometimes smaller than the radius of curvature of the circle of the wound portion 302A at the remaining 3 corners of the battery element 100A around the X direction, as viewed from the front. This is because the angle at which the lead portion 304A of the battery element 100A is led out around the X-direction becomes the starting point of the joint of the 1 st lead portion 304aA and the 2 nd lead portion 304 bA. That is, in the winding portion 302A, the angle at which the lead-out portion 304A of the battery element 100A is led out in the X direction is more difficult to round along the battery element 100A than the remaining 3 angles of the battery element 100A in the X direction. The radius of curvature of the circle of the winding portion 302A at the corner where the lead portion 304A of the battery element 100A is led out around the X direction can be adjusted by, for example, the shape of the corner of at least one of the front cover 210A and the rear cover 220A.

Fig. 5 is a diagram for explaining example 1 of a method for manufacturing a battery cell 10A according to embodiment 1. In example 1, the battery cell 10A is manufactured as follows.

First, battery element 100A is manufactured. The battery element 100A has at least 1 positive electrode 102A, at least 1 negative electrode 104A, and at least 1 separator 106A.

Next, the positive electrode tab 110A and the front cover 210A are joined to each other. Similarly, the negative electrode tab 120A and the rear cover 220A are joined to each other. Next, the positive electrode tab 110A and the positive electrode collector 102aA are bonded to each other. Similarly, the negative electrode tab 120A and the negative electrode collector 104aA are joined to each other. After the positive electrode tab 110A and the positive electrode collector 102aA are joined to each other, the positive electrode tab 110A and the front cover 210A may be joined to each other. Similarly, after the negative electrode tab 120A and the negative electrode collector 104aA are joined to each other, the negative electrode tab 120A and the rear cover 220A may be joined to each other.

Next, the exterior film 300A is wound around the battery element 100A, the front cover 210A, and the rear cover 220A in the X direction for 1 week. Thereby, a winding portion 302A is formed around the battery element 100A, the front cover 210A, and the rear cover 220A in the X direction. The excess length of the exterior film 300A is drawn out from the upper left corners of the battery element 100A, the front cover 210A, and the rear cover 220A as a drawn-out portion 304A, as viewed from the front.

Next, the outer peripheral surface of the front cover 210A around the X direction and the inner peripheral surface of the opening in front of the wound portion 302A around the X direction are joined to each other by thermal welding. Thereby, the front seal portion 510A is formed. Next, the outer peripheral surface of the rear cover 220A around the X direction and the inner peripheral surface of the opening at the rear of the wound portion 302A around the X direction are joined to each other by thermal welding. Thereby, the rear seal 520A is formed. In the example shown in fig. 5, a front seal 510A is also formed at the front end of the lead-out portion 304A. Further, a rear seal 520A is also formed at the rear end of the lead portion 304A. Thus, the 1 st lead-out portion 304aA and the 2 nd lead-out portion 304bA form the liquid injection opening 304cA. The liquid filling opening 304cA opens upward. The storage space 500A is communicated with the external space through the liquid filling opening 304cA. Next, the electrolyte is injected into the storage space 500A through the injection opening 304cA.

Next, the accommodating space 500A is vacuum-sealed. Specifically, after the accommodating space 500A is evacuated through the liquid filling opening 304cA, the 1 st lead-out portion 304aA and the 2 nd lead-out portion 304bA are joined to each other by thermal fusion, thereby forming the side seal 530A.

By evacuating the accommodating space 500A, the battery element 100A is compressed by the winding portion 302A. Therefore, by evacuating the housing space 500A, the wound portion 302A can be strongly wound around the battery element 100A. Therefore, as shown in fig. 4, both ends in the Z direction of the separator 106A located at both ends in the Y direction of the battery element 100A are bent toward the center in the Y direction of the battery element 100A. Therefore, the winding portion 302A is rounded along the curvature of both ends of these separators 106A in the Z direction at 4 corners around the X direction of the battery element 100A. Therefore, the volume of the battery cell 10A can be reduced. Therefore, the volumetric energy density of the battery cell 10A can be improved.

Next, the lead portion 304A can be bent along the upper surface of the battery element 100A.

In this way, the battery cell 10A is manufactured.

The manufacturing method of the battery cell 10A is not limited to the above-described example. For example, before wrapping the exterior film 300A around the X-direction of the battery element 100A for 1 week, a folding line along at least one of the 4 corners around the X-direction of the battery element 100A may be formed in advance in the exterior film 300A. For example, a folding line may be set in advance at the corner at or near the start point of winding of the exterior film 300A. The outer film 300A can be easily wound around the X-direction of the battery element 100A by the folding line.

Fig. 6 is a diagram for explaining example 2 of a method for manufacturing the battery cell 10A according to embodiment 1. The example 2 is the same as the example 1 described above, except for the following points.

First, battery element 100A was manufactured in the same manner as in example 1. Next, as in example 1, the positive electrode tab 110A and the front cover 210A are joined to each other. Further, the negative electrode tab 120A and the rear cover 220A are joined to each other. Next, as in example 1, the positive electrode tab 110A and the positive electrode current collector 102aA are bonded to each other. Further, the negative electrode tab 120A and the negative electrode collector 104aA are joined to each other. In example 2, as shown in fig. 6, a pouring hole 210aA is provided in the front surface of the front cover 210A. The storage space 500A is communicated with the external space through the filling hole 210aA.

Next, the exterior film 300A is wound around the battery element 100A, the front cover 210A, and the rear cover 220A in the X direction to form the winding portion 302A and the lead-out portion 304A. Next, the outer peripheral surface of the front cover 210A around the X direction and the inner peripheral surface of the opening in front of the wound portion 302A around the X direction are joined to each other by thermal welding. Thereby, the front seal portion 510A is formed. Next, the outer peripheral surface of the rear cover 220A around the X direction and the inner peripheral surface of the opening at the rear of the wound portion 302A around the X direction are joined to each other by thermal welding. Thereby, the rear seal 520A is formed. Next, the 1 st lead-out portion 304aA and the 2 nd lead-out portion 304bA are bonded to each other by thermal fusion. Thereby, the side seal 530A is formed.

Then, the electrolyte is injected into the storage space 500A through the injection hole 210 aA. Next, the accommodating space 500A is vacuum-sealed. Specifically, after the accommodating space 500A is evacuated through the pouring hole 210aA, the pouring hole 210aA is blocked by a given cover member. As in example 1, by evacuating the housing space 500A, the wound portion 302A is rounded along the battery element 100A at least 1 corner of the battery element 100A around the X direction. Therefore, the volume of the battery cell 10A can be reduced. Therefore, the volumetric energy density of the battery cell 10A can be improved.

Next, as in example 1, the lead portion 304A is bent along the upper surface of the battery element 100A.

In this way, the battery cell 10A is manufactured.

While embodiment 1 of the present invention has been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can be adopted.

For example, in embodiment 1, the positive electrode tab 110A and the negative electrode tab 120A are disposed on opposite sides of the battery element 100A in the X direction. However, both the positive electrode tab 110A and the negative electrode tab 120A may be disposed on only one of the front side and the rear side in the X direction of the battery element 100A. In this case, the front end and the rear end of battery element 100A are covered with, for example, 2 covers. Alternatively, only the side of the battery element 100A from which the positive electrode tab 110A and the negative electrode tab 120A are drawn may be covered with a cover. In this example, the exterior film 300A may be sealed on the opposite side of the lid of the battery element 100A and folded along the battery element 100A.

(embodiment 2)

Embodiment 2 and modifications of the present invention will be described below with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof is omitted.

Fig. 7 is a right side view of battery cell 10B according to embodiment 2. Fig. 8 is a schematic view of section B-B of fig. 7. Fig. 7 illustrates a state of being transmitted through the exterior film 300B for the sake of explanation.

In the drawings, for the sake of explanation, X direction, Y direction, and Z direction are labeled. The X direction represents the front-rear direction of the battery cell 10B. The Y direction is orthogonal to the X direction. The Y direction represents the left-right direction of the battery cell 10B. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 10B. The direction pointed by the arrow representing the X direction, the direction pointed by the arrow representing the Y direction, and the direction pointed by the arrow representing the Z direction are the rear direction, the left direction, and the upper direction, respectively. The relationship among the X direction, Y direction, Z direction, front-rear direction, left-right direction, and up-down direction of the battery cell 10B is not limited to this example.

The battery cell 10B includes the battery element 100B, the positive electrode tab 110B, the negative electrode tab 120B, the front cover 210B, the rear cover 220B, and the exterior film 300B. The exterior film 300B has a winding portion 302B and a lead-out portion 304B.

The battery element 100B has a substantially rectangular parallelepiped shape. The longitudinal direction of battery element 100B is substantially parallel to the X direction. The length of the battery element 100B in the X direction is not limited to the following, but is, for example, 300mm to 500mm, and preferably 450 mm. The short side direction of battery element 100B is substantially parallel to the Z direction. The width of battery element 100B in the Z direction is not limited to the following, but is, for example, 90mm to 130mm, preferably 120 mm. The thickness direction of battery element 100B is substantially parallel to the Y direction. The thickness of battery element 100B in the Y direction is not limited to the following, and is, for example, 20mm to 50mm, preferably 45 mm. The shape of battery element 100B is not limited to this example.

The battery element 100B has at least 1 positive electrode not shown, at least 1 negative electrode not shown, and at least 1 separator not shown. For example, a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked in the Y direction. At least a part of the separator is located between the positive electrode and the negative electrode adjacent in the Y direction. For example, a plurality of sheet-like separators may be respectively located between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the 1 sheet-like separator may have a serpentine shape passing through a region between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the positive electrode, the negative electrode, and the separator may be wound such that the separator is disposed between the positive electrode and the negative electrode. In one example, the positive electrode, the negative electrode, and the separator are wound in a state where one or both surfaces of the positive electrode and the negative electrode are covered with the separator. In other examples, a laminate including a plurality of unit laminates including the positive electrode, the separator, and the negative electrode in this order may be wound. However, the wound structure of the positive electrode, the negative electrode, and the separator is not limited to these examples.

The positive electrode tab 110B is disposed in front of the battery element 100B. The rear end portion of the positive electrode tab 110B is electrically connected to the positive electrode collector 102 aB. Positive electrode current collector 102aB is drawn forward from the positive electrode of battery element 100B. Thus, the positive electrode tab 110B is electrically connected to the positive electrode of the battery element 100B.

The negative electrode tab 120B is disposed behind the battery element 100B. The distal end portion of the negative electrode tab 120B is electrically connected to the negative electrode collector 104 aB. The negative electrode current collector 104aB is drawn rearward from the negative electrode of the battery element 100B. Thus, negative electrode tab 120B is electrically connected to the negative electrode of battery element 100B.

The front cover 210B covers the front end of the battery element 100B. The front cover 210B contains, for example, resin, metal, or the like. The front end of the positive electrode tab 110B protrudes from the front surface of the front cover 210B. The front cover 210B has a substantially rectangular shape when viewed from the front. The long side direction of the front cover 210B is substantially parallel to the Z direction, and the short side direction of the front cover 210B is substantially parallel to the Y direction, as viewed from the front.

The rear cover 220B covers the rear end of the battery element 100B. The rear cover 220B contains, for example, resin, metal, or the like. The rear end of the negative electrode tab 120B protrudes from the rear surface of the rear cover 220B. The rear cover 220B has a substantially rectangular shape when viewed from the rear. The long side direction of the rear cover 220B is substantially parallel to the Z direction, and the short side direction of the rear cover 220B is substantially parallel to the Y direction, as viewed from the rear.

The winding portion 302B has a substantially tubular shape that is open both forward and rearward. Thus, the wound portion 302B has an inner circumferential surface 302aB and an outer circumferential surface 302bB. The inner peripheral surface 302aB is located inside the periphery of the battery element 100B of the exterior film 300B around the X direction. The outer peripheral surface 302bB is located outside the periphery of the battery element 100B of the outer film 300B around the X direction.

The front cover 210B is disposed inside the opening in front of the winding portion 302B. The rear cover 220B is disposed inside the opening at the rear of the winding portion 302B. The winding portion 302B winds around the X direction for 1 week at the battery element 100B, the front cover 210B, and the rear cover 220B. Thus, the front cover 210B, the rear cover 220B, and the winding portion 302B form a housing space 500B that houses the battery element 100B. In the housing space 500B, an electrolyte solution, not shown, is housed together with the battery element 100B.

The outer peripheral surface of the front cover 210B around the X direction and the inner peripheral surface 302aB around the X direction of the opening in front of the wound portion 302B are joined to each other by, for example, thermal welding. Thereby, front seal 510B is formed in front of battery element 100B.

The outer peripheral surface of the rear cover 220B around the X direction and the inner peripheral surface 302aB around the X direction of the opening at the rear of the wound portion 302B are joined to each other by, for example, thermal welding. Thereby, rear seal 520B is formed at the rear of battery element 100B.

As shown in fig. 8, the lead-out portion 304B is led out from one end of the corner of the wound portion 302B located on the lower right side of the battery element 100B, as viewed from the front. The lead portion 304B is bent along the right side surface of the battery element 100B. Thus, the lead-out portion 304B has an inner surface 304aB and an outer surface 304bB. Inner surface 304aB is located on the side where battery element 100B is located. The outer surface 304bB is located on the opposite side of the side on which the battery element 100B is located. On the right side surface side of battery element 100B, outer peripheral surface 302bB of wound portion 302B and inner surface 304aB of lead-out portion 304B are joined to each other by, for example, thermal welding. Thereby, a side seal 530B is formed on the right side of battery element 100B. That is, the side seal 530B includes a junction of the winding portion 302B and the lead portion 304B. Side seal 530B is formed along the right side surface of battery element 100B. Therefore, the protrusion of the side seal 530B can be suppressed without bending the side seal 530B.

The inner peripheral surface and the outer peripheral surface of the battery element 100B of the exterior film 300B around the circumference in the X direction can be made of thermoplastic resin such as polypropylene (PP) resin, for example. In this example, the outer peripheral surface 302bB of the winding portion 302B and the inner surface 304aB of the lead-out portion 304B can be set to be thermoplastic resins. Therefore, the outer peripheral surface 302bB of the wound portion 302B and the inner surface 304aB of the drawn portion 304B can be easily joined by thermal fusion.

In embodiment 2, the thickness of battery element 100B in the Y direction is smaller than the width of battery element 100B in the Z direction. In this case, the side surfaces of the battery element 100B on both sides in the Y direction can be made flatter than the side surfaces of the battery element 100B on both sides in the Z direction. For example, when a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators are stacked in the thickness direction of the battery element 100B, the positive electrodes, the negative electrodes, and the ends of the separators are provided on the side surfaces of the both sides in the width direction of the battery element 100B. Alternatively, in the case where the separator is in a serpentine shape passing through the region between the positive and negative electrodes alternately stacked in the thickness direction of the battery element 100B, there is folding back of the separator on the side surfaces of both sides in the width direction of the battery element 100B. Alternatively, when the positive electrode, the negative electrode, and the separator are wound, the positive electrode, the negative electrode, and the separator are bent on the side surfaces of the battery element 100B on both sides in the width direction. Therefore, in any of these structures of battery element 100B, both side surfaces of battery element 100B in the Y direction can be made flatter than both side surfaces of battery element 100B in the Z direction. In embodiment 2, side seal 530B overlaps at least a portion of a surface of battery element 100B that is substantially perpendicular to the Y direction. Specifically, the side seal 530B overlaps at least a portion of the right-facing surface of the battery element 100B. Therefore, the side seal 530B can be disposed along the relatively flat surface of the battery element 100B. Therefore, side seal 530B can be formed more easily than when side seal 530B overlaps a surface of battery element 100B that is substantially perpendicular to the Z direction.

In one example, a plurality of battery cells 10B may be stacked in the Y direction to form a battery module. In this example, the lower surface of each battery cell 10B is desirably flat. In embodiment 2, the side seal 530B is located laterally of the battery element 100B and is not located below the battery element 100B. Therefore, the lower surface of the battery cell 10B can be flattened, as compared with the case where the side seal 530B is located below the battery element 100B. The position where the side seal 530B is provided is not limited to the position according to embodiment 2. The side seal 530B may be located above the battery element 100B, for example. That is, the side seal 530B can be located at any portion other than the lower portion of the periphery of the battery element 100B in the X direction.

In the example shown in fig. 8, the length of the lead portion 304B in the Z direction is substantially equal to the width of the battery element 100B in the Z direction. That is, the side seal 530B overlaps substantially the entire right side surface of the battery element 100B. However, the length of lead portion 304B in the Z direction may be shorter than the width of battery element 100B in the Z direction. For example, the length of lead portion 304B in the Z direction may be 50% or less of the width of battery element 100B in the Z direction. That is, the side seal 530B may overlap only a portion of the right side surface of the battery element 100B.

Fig. 9 is a diagram for explaining an example of a method for manufacturing the battery cell 10B according to embodiment 2. In fig. 9, the direction pointed by the arrow indicating the Y direction and the direction pointed by the arrow indicating the Z direction are the lower direction and the left direction, respectively. In this example, the battery cell 10B is manufactured as follows.

First, battery element 100B is manufactured. The battery element 100B has at least 1 positive electrode, at least 1 negative electrode, and at least 1 separator.

Next, the positive electrode tab 110B and the front cover 210B are joined to each other. Similarly, the negative electrode tab 120B and the rear cover 220B are joined to each other. Next, the positive electrode tab 110B and the positive electrode collector 102aB are bonded to each other. Similarly, the negative electrode tab 120B and the negative electrode collector 104aB are joined to each other. After the positive electrode tab 110B and the positive electrode collector 102aB are joined to each other, the positive electrode tab 110B and the front cover 210B may be joined to each other. Similarly, after the negative electrode tab 120B and the negative electrode collector 104aB are joined to each other, the negative electrode tab 120B and the rear cover 220B may be joined to each other.

Next, the exterior film 300B was wound around the battery element 100B for 1 week in the X direction. Thereby, the winding portion 302B is formed. The excess length of the exterior film 300B is drawn out as a drawn-out portion 304B. In the example shown in fig. 9, the lead-out portion 304B is led out from one end of the wound portion 302B located at the corner of the upper right side of the battery element 100B around the X direction, as viewed from the front. Further, above battery element 100B, outer peripheral surface 302bB of wound portion 302B and inner surface 304aB of lead portion 304B face each other.

Next, as shown in fig. 9, a base material 602B is disposed between the upper surface of the battery element 100B and the inner peripheral surface 302aB of the wound portion 302B. The base 602B is, for example, a relatively high-hardness plate. In a state where the base material 602B is disposed between the upper surface of the battery element 100B and the inner peripheral surface 302aB of the wound portion 302B, the wound portion 302B and the wound portion 304B are hot-pressed in the Y direction by the hot press 600B from above the drawn portion 304B. Thereby, the outer peripheral surface 302bB of the wound portion 302B and the inner surface 304aB of the lead portion 304B are joined to each other by thermal fusion. In this way, the side seal 530B is formed. Next, the substrate 602B is taken out of the housing space 500B.

Next, the outer peripheral surface around the X direction of the front cover 210B and the inner peripheral surface 302aB around the X direction of the opening in front of the wound portion 302B are joined to each other by thermal fusion. Thereby, the front seal portion 510B is formed. Next, the outer peripheral surface around the X direction of the rear cover 220B and the inner peripheral surface 302aB around the X direction of the rear opening of the wound portion 302B are joined to each other by thermal fusion. Thereby, the rear seal 520B is formed.

Next, an electrolyte is injected into the storage space 500B. For example, the electrolyte is injected through an injection hole provided in at least one of the front cover 210B and the rear cover 220B. Next, the accommodating space 500B is vacuum sealed. For example, the accommodating space 500B is evacuated through the filling hole. In this example, after vacuum sealing the receiving space 500B, the pour hole is plugged by a given cap.

In this way, the battery cell 10B is manufactured.

Fig. 10 is a cross-sectional view of a battery cell 10B1 according to a modification. The battery cell 10B1 according to the modification is the same as the battery cell 10B according to embodiment 2, except for the following points.

The exterior film 300B1 according to the modification includes a winding portion 302B1 and a lead portion 304B1. The winding portion 302B1 has an inner peripheral surface 302aB1 and an outer peripheral surface 302bB1. The lead-out portion 304B1 has an inner surface 304aB1 and an outer surface 304bB1.

As shown in fig. 10, the lead-out portion 304B1 is led out from one end of the corner of the wound portion 302B1 located on the upper right side of the battery element 100B, as viewed from the front. The lead portion 304B1 is bent along the upper side of the battery element 100B. On the upper side surface side of battery element 100B, outer peripheral surface 302bB1 of wound portion 302B1 and inner surface 304aB1 of lead portion 304B1 are joined to each other, for example, by thermal welding. Thereby, side seal 530B1 is formed above battery element 100B. That is, the side seal 530B1 includes a junction between the winding portion 302B1 and the lead portion 304B1. Side seal 530B1 is formed along the upper side of battery element 100B. Therefore, the protrusion of the side seal 530B1 can be suppressed without bending the side seal 530B1.

In one example, a plurality of battery cells 10B1 may be stacked in the Y direction to form a battery module. In the modification, the side seal 530B1 overlaps at least a part of the surface of the battery element 100B that is substantially perpendicular to the Z direction. Specifically, the side seal 530B1 overlaps at least a portion of the upward facing surface of the battery element 100B. Therefore, in the modification, the length of the battery module in the Y direction can be shortened by a corresponding amount without the side seal 530B1 between the adjacent battery cells 10B1 in the Y direction, compared to the case where the side seal 530B1 overlaps at least a portion of the surface of the battery element 100B perpendicular to the Y direction. Therefore, in the modification, the volume efficiency of the battery module can be improved as compared with the case where the side seal 530B1 overlaps at least a part of the surface of the battery element 100B substantially perpendicular to the Y direction.

In the example shown in fig. 10, the length of the lead portion 304B1 in the Y direction is substantially equal to the thickness of the battery element 100B in the Y direction. That is, the side seal 530B1 overlaps substantially the entire upper side surface of the battery element 100B. However, the length of the lead portion 304B1 in the Y direction may be shorter than the thickness of the battery element 100B in the Y direction. For example, the length of the lead portion 304B1 in the Y direction may be 50% or less of the thickness of the battery element 100B in the Y direction. That is, the side seal 530B1 may overlap only a portion of the upper side surface of the battery element 100B.

Embodiment 2 and modifications of the present invention are described above with reference to the drawings, and these are examples of the present invention, and various configurations other than those described above can be adopted.

For example, in embodiment 2, the positive electrode tab 110B and the negative electrode tab 120B are disposed on opposite sides of the battery element 100B in the X direction. However, both the positive electrode tab 110B and the negative electrode tab 120B may be disposed on only one of the front side and the rear side in the X direction of the battery element 100B. In this case, the front end and the rear end of battery element 100B are covered with, for example, 2 covers. Alternatively, only the side of the battery element 100B from which the positive electrode tab 110B and the negative electrode tab 120B are drawn may be covered with a cover. In this example, the exterior film 300B may be sealed on the opposite side of the lid of the battery element 100B and folded along the battery element 100B.

Embodiment 3

Embodiment 3 and modifications of the present invention will be described below with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof is omitted.

Fig. 11 is a front perspective view of battery cell 10C according to embodiment 3. Fig. 12 is a front enlarged perspective view of a part of battery cell 10C according to embodiment 3. Fig. 13 is a right side view of battery cell 10C according to embodiment 3. Fig. 14 is a schematic view of section C-C of fig. 12. Fig. 13 illustrates a state of transmitting the exterior film 300C for the sake of explanation.

In the drawings, for the sake of explanation, X direction, Y direction, and Z direction are labeled. The X direction indicates the front-rear direction of the battery cell 10C. The Y direction is orthogonal to the X direction. The Y direction represents the left-right direction of the battery cell 10C. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 10C. The direction pointed by the arrow representing the X direction, the direction pointed by the arrow representing the Y direction, and the direction pointed by the arrow representing the Z direction are the rear direction, the left direction, and the upper direction, respectively. The relationship among the X direction, Y direction, Z direction, front-rear direction, left-right direction, and up-down direction of the battery cell 10C is not limited to this example.

The battery cell 10C includes the battery element 100C, the positive electrode tab 110C, the negative electrode tab 120C, the front cover 210C, the rear cover 220C, and the exterior film 300C. The exterior film 300C has a winding portion 302C and a lead-out portion 304C.

The battery element I00C has a substantially rectangular parallelepiped shape. The longitudinal direction of battery element 100C is substantially parallel to the X direction. The length of the battery element 100C in the X direction is not limited to the following, but is, for example, 300mm to 500mm, and preferably 450 mm. The short side direction of battery element 100C is substantially parallel to the Z direction. The length of battery element 100C in the Z direction is not limited to the following, but is, for example, 90mm to 130mm, preferably 120 mm. The thickness direction of battery element 100C is substantially parallel to the Y direction. The thickness of the battery element 100C in the Y direction is not limited to the following, and is, for example, 20mm to 50mm, preferably 45 mm. The shape of battery element 100C is not limited to this example.

The battery element 100C has at least 1 positive electrode not shown, at least 1 negative electrode not shown, and at least 1 separator not shown. For example, a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked in the Y direction. At least a part of the separator is located between the positive electrode and the negative electrode adjacent in the Y direction. For example, a plurality of sheet-like separators may be respectively located between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the 1 sheet-like separator may have a serpentine shape passing through a region between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the positive electrode, the negative electrode, and the separator may be wound such that the separator is disposed between the positive electrode and the negative electrode. In one example, the positive electrode, the negative electrode, and the separator are wound in a state where one or both surfaces of the positive electrode and the negative electrode are covered with the separator. In other examples, a laminate including a plurality of unit laminates including the positive electrode, the separator, and the negative electrode in this order may be wound. However, the wound structure of the positive electrode, the negative electrode, and the separator is not limited to these examples.

The positive electrode tab 110C is disposed in front of the battery element 100C. The rear end portion of the positive electrode tab 110C is electrically connected to the positive electrode collector 102 aC. The positive electrode current collector 102aC is drawn forward from the positive electrode of the battery element 100C. Thus, the positive electrode tab 110C is electrically connected to the positive electrode of the battery element 100C.

The negative electrode tab 120C is disposed behind the battery element 100C. The tip end portion of the negative electrode tab 120C is electrically connected to the negative electrode collector 104 aC. The negative electrode current collector 104aC is drawn rearward from the negative electrode of the battery element 100C. Thus, negative electrode tab 120C is electrically connected to the negative electrode of battery element 100C.

The front cover 210C covers the front end portion of the battery element 100C. The front cover 210C contains, for example, resin, metal, or the like. The front end of the positive electrode tab 110C is led out from the front surface of the front cover 210C. The front cover 210C has a substantially rectangular shape when viewed from the front. The long side direction of the front cover 210C is substantially parallel to the Z direction, and the short side direction of the front cover 210C is substantially parallel to the Y direction, as viewed from the front.

The rear cover 220C covers the rear end of the battery element 100C. The rear cover 220C contains, for example, resin, metal, or the like. The rear end of the negative electrode tab 120C is led out from the rear surface of the rear cover 220C. The rear cover 220C has a substantially rectangular shape when viewed from the rear. The long side direction of the rear cover 220C is substantially parallel to the Z direction, and the short side direction of the rear cover 220C is substantially parallel to the Y direction, as viewed from the rear.

As shown in fig. 11 and 12, the winding portion 302C has a substantially tubular shape that is open both forward and rearward. Inside the opening in front of the winding portion 302C, a front cover 210C is disposed in addition to a front convex portion 212C described later. Inside the opening at the rear of the winding portion 302C, a rear cover 220C is disposed in addition to a rear convex portion 222C described later. The winding portion 302C winds around the X direction for 1 week at the battery element 100C, the front cover 210C, and the rear cover 220C. Thus, front cover 210C, rear cover 220C, and winding portion 302C form accommodating space 500C for accommodating battery element 100C. In the housing space 500C, an electrolyte solution, not shown, is housed together with the battery element 100C. In addition, the manner of winding the battery element 100C of the winding portion 302C is not limited to the above-described example.

An outer peripheral surface of the front cover 210C around the X direction and an inner peripheral surface of the opening in front of the wound portion 302C around the X direction are joined to each other by, for example, thermal welding. Thereby, the front seal portion 510C is formed.

An outer peripheral surface of the rear cover 220C around the X direction and an inner peripheral surface of the opening at the rear of the wound portion 302C around the X direction are joined to each other by, for example, thermal welding. Thereby, the rear seal 520C is formed.

As shown in fig. 11 and 12, the lead-out portion 304C is led out from the upper left corner of the battery element 100C of the winding portion 302C, as viewed from the front. Specifically, as shown in fig. 12, the lead-out portion 304C includes a 1 st lead-out portion 304aC and a 2 nd lead-out portion 304bC. The 1 st lead-out portion 304aC is led out from one of both ends of the winding portion 302C around the circumferential direction in the X direction. The 2 nd lead-out portion 304bC is led out from the other of the two ends of the winding portion 302C around the circumferential direction in the X direction. The 1 st lead-out portion 304aC and the 2 nd lead-out portion 304bC are bonded to each other by, for example, thermal fusion. Thereby, the side seal 530C is formed as viewed from the front. The lead portion 304C is bent along the upper surface of the battery element 100C. The lead portion 304C may not be bent. The shape of the bending of the lead portion 304C is not limited to the shape according to embodiment 3.

As shown in fig. 11, 12, and 14, a front convex portion 212C is provided on the outer peripheral surface of the front cover 210C. The front convex portion 212C is provided on the entire outer peripheral surface of the front cover 210C. The front convex portion 212C may be provided only on a part of the entire outer peripheral surface of the front cover 210C. The front convex portion 212C is located in front of the front end portion of the exterior film 300. Thereby, the front convex portion 212C covers the front end portion of the exterior film 300C. Therefore, the front convex portion 212C can suppress the exposure of the front end portion of the exterior film 300C. Therefore, even if a conductor such as a conductive sheet contained in the outer film 300C is exposed from the tip portion of the outer film 300C, a short circuit through the outer film 300C of the conductor can be suppressed.

As shown in fig. 11, a rear convex portion 222C is provided on the outer peripheral surface of the rear cover 220C in the same manner as the outer peripheral surface of the front cover 210C. The rear convex portion 222C covers the rear end portion of the exterior film 300C as in the front convex portion 212C. Therefore, the rear convex portion 222C can suppress the exposure of the rear end portion of the exterior film 300C. Therefore, even if a conductor such as a conductive sheet contained in the outer film 300C is exposed from the rear end portion of the outer film 300C, a short circuit through the outer film 300C of the conductor can be suppressed.

In embodiment 3, both the front convex portion 212C and the rear convex portion 222C are provided. However, only one of the front convex portion 212C and the rear convex portion 222C may be provided.

Next, an example of a method for manufacturing the battery cell 10C according to embodiment 3 will be described. In this example, the battery cell 10C according to embodiment 3 is manufactured as follows.

First, battery element 100C is manufactured. The battery element 100C has at least 1 positive electrode, at least 1 negative electrode, and at least 1 separator.

Next, the positive electrode tab 110C and the front cover 210C are joined to each other. Similarly, the negative electrode tab 120C and the rear cover 220C are joined to each other. Next, the positive electrode tab 110C and the positive electrode collector 102aC are bonded to each other. Similarly, the negative electrode tab 120C and the negative electrode collector 104aC are joined to each other. After the positive electrode tab 110C and the positive electrode collector 102aC are joined to each other, the positive electrode tab 110C and the front cover 210C may be joined to each other. Similarly, after the negative electrode tab 120C and the negative electrode collector 104aC are joined to each other, the negative electrode tab 120C and the rear cover 220C may be joined to each other.

Next, the exterior film 300C is wound around the battery element 100C, the front cover 210C, and the rear cover 220C for 1 week in the X direction. Thereby, the winding portion 302C is formed. Further, the excess length of the exterior film 300C is drawn out as a drawn-out portion 304C. In this state, the front convex portion 212C is located in front of the front end portion of the exterior film 300C. Thereby, the front end portion of the exterior film 300C is covered with the front convex portion 212C. Further, the rear convex portion 222C is located rearward of the rear end portion of the exterior film 300C. Thereby, the rear end portion of the exterior film 300C is covered with the rear convex portion 222C.

Next, the outer peripheral surface of the front cover 210C around the X direction and the inner peripheral surface of the opening in front of the wound portion 302C around the X direction are joined to each other by thermal welding. Thereby, the front seal portion 510C is formed. Next, the outer peripheral surface of the rear cover 220C around the X direction and the inner peripheral surface of the opening at the rear of the wound portion 302C around the X direction are joined to each other by thermal welding. Thereby, the rear seal 520C is formed.

Next, the electrolyte is injected into the accommodating space 500C through the gap between the 1 st lead-out portion 304aC and the 2 nd lead-out portion 304 bC. Then, the accommodating space 500C is evacuated through the gap between the 1 st lead-out portion 304aC and the 2 nd lead-out portion 304 bC. Next, the 1 st lead portion 304aC and the 2 nd lead portion 304bC are joined by thermal fusion, thereby forming the side seal 530C. Thereby, the accommodating space 500C is vacuum-sealed.

The method of vacuum sealing the housing space 500C is not limited to the above example. In other examples, first, the 1 st lead portion 304aC and the 2 nd lead portion 304bC are joined by thermal fusion, to form the side seal 530C. Next, the electrolyte is injected into the storage space 500C through the injection hole provided in at least one of the front cover 210C and the rear cover 220C. Then, the accommodating space 500C is evacuated through the filling hole. The filling hole is then plugged by a given cap.

Next, the side seal 530C is bent along the upper surface of the battery element 100C.

In this way, the battery cell 10C is manufactured.

Fig. 15 is a diagram showing a modification of fig. 14.

The front cover 210C1 of the battery cell 10C1 according to the modification has a front coating portion 212C1. The front coating portion 212C1 covers the front end portion of the outer film 300C and the vicinity of the front end portion of the outer peripheral surface of the outer film 300C. Specifically, the front cover 212C1 covers the upper surface of the side seal 530C above the housing space 500C and in the vicinity of the front end of the outer film 300C. When the front coating portion 212C1 covers at least a part of the front end portion of the outer coating film 300C, even if a conductor such as a conductive sheet contained in the outer coating film 300C is exposed from the front end portion of the outer coating film 300C, a short circuit through the outer coating film 300C of the conductor can be suppressed. When the front coating portion 212C1 covers at least a part of the outer peripheral surface of the outer coating film 300C, the position of the front end portion of the outer coating film 300C can be fixed by the front coating portion 212C1.

In one example, the front coating portion 212C1 can be formed by deforming the front convex portion 212C according to embodiment 3. For example, after all the steps of the method for manufacturing the battery cell 10C according to embodiment 3 are completed, heat is applied to the front convex portion 212C and the front convex portion 212C is crushed, whereby the material constituting the front convex portion 212C flows rearward. Thus, the material constituting the front convex portion 212C covers not only the front end portion of the outer coating film 300C but also the outer peripheral surface of the outer coating film 300C. In particular, when the side seal 530C is bent along the battery element 100C before the front convex portion 212C is deformed, the outer surface of the side seal 530C can be covered by the front cover 212C1.

In the example shown in fig. 15, the configuration of the front cover 210C1 is explained. The configuration of the front cover 210C1 in fig. 15 is also applicable to the rear cover.

While embodiment 3 and the modification of the present invention have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can be adopted.

For example, in embodiment 3, the positive electrode tab 110C and the negative electrode tab 120C are disposed on opposite sides of the battery element 100C in the X direction. However, both the positive electrode tab 110C and the negative electrode tab 120C may be disposed on only one of the front side and the rear side in the X direction of the battery element 100C. In this case, the front end and the rear end of battery element 100C are covered with, for example, 2 covers. Alternatively, only the side of the battery element 100C from which the positive electrode tab 110C and the negative electrode tab 120C are drawn may be covered with a cover. In this example, the exterior film 300C may be sealed on the opposite side of the lid of the battery element 100C and folded along the battery element 100C.

Embodiment 4

Embodiment 4 and modifications of the present invention will be described below with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof is omitted.

Fig. 16 is a front perspective view of battery cell 10D according to embodiment 4. Fig. 17 is a front enlarged perspective view of a part of battery cell 10D according to embodiment 4. Fig. 18 is a right side view of battery cell 10D according to embodiment 4. Fig. 19 is a schematic view of section D-D of fig. 18. Fig. 18 illustrates a state of being transmitted through the exterior film 300D for the sake of explanation.

In the drawings, for the sake of explanation, X direction, Y direction, and Z direction are labeled. The X direction indicates the front-rear direction of the battery cell 10D. The Y direction is orthogonal to the X direction. The Y direction represents the left-right direction of the battery cell 10D. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 10D. The direction pointed by the arrow representing the X direction, the direction pointed by the arrow representing the Y direction, and the direction pointed by the arrow representing the Z direction are the rear direction, the left direction, and the upper direction, respectively. The relationship among the X direction, Y direction, Z direction, front-rear direction, left-right direction, and up-down direction of the battery cell 10D is not limited to this example.

The battery cell 10D includes the battery element 100D, the positive electrode tab 110D, the negative electrode tab 120D, the front cover 210D, the rear cover 220D, and the exterior film 300D. The exterior film 300D has a winding portion 302D and a lead-out portion 304D.

The battery element 100D has a substantially rectangular parallelepiped shape. The longitudinal direction of battery element 100D is substantially parallel to the X direction. The length of the battery element 100D in the X direction is not limited to the following, but is, for example, 300mm to 500mm, and preferably 450 mm. The short side direction of battery element 100D is substantially parallel to the Z direction. The length of battery element 100D in the Z direction is not limited to the following, but is, for example, 90mm to 130mm, preferably 120 mm. The thickness direction of battery element 100D is substantially parallel to the Y direction. The thickness of the battery element 100D in the Y direction is not limited to the following, and is, for example, 20mm to 50mm, preferably 45 mm. The shape of battery element 100D is not limited to this example.

The battery element 100D has at least 1 positive electrode not shown, at least 1 negative electrode not shown, and at least 1 separator not shown. For example, a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked in the Y direction. At least a part of the separator is located between the positive electrode and the negative electrode adjacent in the Y direction. For example, a plurality of sheet-like separators may be respectively located between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the 1 sheet-like separator may have a serpentine shape passing through a region between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the positive electrode, the negative electrode, and the separator may be wound such that the separator is disposed between the positive electrode and the negative electrode. In one example, the positive electrode, the negative electrode, and the separator are wound in a state where one or both surfaces of the positive electrode and the negative electrode are covered with the separator. In other examples, a laminate including a plurality of unit laminates including the positive electrode, the separator, and the negative electrode in this order may be wound. However, the wound structure of the positive electrode, the negative electrode, and the separator is not limited to these examples.

As shown in fig. 18, positive electrode tab 110D is disposed in front of battery element 100D. The rear end portion of the positive electrode tab 110D is electrically connected to the positive electrode current collector 102 aD. The positive electrode current collector 102aD is drawn forward from the positive electrode. Thus, the positive electrode tab 110D is electrically connected to the plurality of positive electrodes. As shown in fig. 19, a plurality of positive electrode current collectors 102aD are collected between battery element 100D and front cover 210D. In other words, a plurality of collecting portions of positive electrode current collector 102aD exist between battery element 100D and positive electrode tab 110D. The width in the Y direction of the collection portion of the plurality of positive electrode current collectors 102aD becomes narrower as going forward from battery element 100D. In fig. 19, a plurality of positive electrode current collectors 102aD led out from the battery element 100D and collected are schematically illustrated as a triangular shape.

As shown in fig. 18, negative electrode tab 120D is disposed behind battery element 100D. The distal end portion of the negative electrode tab 120D is electrically connected to the negative electrode current collector 104 aD. The negative electrode current collector 104aD is drawn from the negative electrode to the rear. Thus, the negative electrode tab 120D is electrically connected to the plurality of negative electrodes. As in the example shown in fig. 19, a plurality of collecting portions of negative electrode current collector 104aD are present between battery element 100D and negative electrode tab 120D.

The front cover 210D covers the front end portion of the battery element 100D. The front cover 210D contains, for example, resin, metal, or the like. The front end portion of the positive electrode tab 110D is led forward from the front surface of the front cover 210D. The front cover 210D has a substantially rectangular shape when viewed from the front. The long side direction of the front cover 210D is substantially parallel to the Z direction, and the short side direction of the front cover 210D is substantially parallel to the Y direction, as viewed from the front.

The rear cover 220D covers the rear end of the battery element 100D. The rear cover 220D contains, for example, resin, metal, or the like. The rear end of the negative electrode tab 120D is led out rearward from the rear surface of the rear cover 220D. The rear cover 220D has a substantially rectangular shape when viewed from the rear. The long side direction of the rear cover 220D is substantially parallel to the Z direction, and the short side direction of the rear cover 220D is substantially parallel to the Y direction, as viewed from the rear.

As shown in fig. 16 and 17, the winding portion 302D has a substantially tubular shape that is open both forward and rearward. The front cover 210D is disposed inside the opening in front of the winding portion 302D. The rear cover 220D is disposed inside the opening at the rear of the winding portion 302D. The winding portion 302D winds around the X direction for 1 week at the battery element 100D, the front cover 210D, and the rear cover 220D. Thus, front cover 210D, rear cover 220D, and winding portion 302D form accommodating space 500D for accommodating battery element 100D. The battery element 100D is housed together with an electrolyte solution, not shown, in the housing space 500D. In addition, the manner of winding the battery element 100D of the winding portion 302D is not limited to the above-described example.

An outer peripheral surface of the front cover 210D around the X direction and an inner peripheral surface of the opening in front of the wound portion 302D around the X direction are joined to each other by, for example, thermal welding. Thereby, the front seal portion 510D is formed.

An outer peripheral surface of the rear cover 220D around the X direction and an inner peripheral surface of the opening at the rear of the wound portion 302D around the X direction are joined to each other by, for example, thermal welding. Thereby, the rear seal 520D is formed.

As shown in fig. 16 and 17, the lead-out portion 304D is led out from the upper left corner of the battery element 100D of the winding portion 302D, as viewed from the front. Specifically, as shown in fig. 17, the lead-out portion 304D includes a 1 st lead-out portion 304aD and a 2 nd lead-out portion 304bD. The 1 st lead-out portion 304aD is led out from one of both ends of the winding portion 302D around the circumferential direction in the X direction. The 2 nd lead-out portion 304bD is led out from the other of the two ends of the winding portion 302D around the circumferential direction in the X direction. The 1 st lead-out portion 304aD and the 2 nd lead-out portion 304bD are joined to each other by, for example, thermal fusion. Thereby, the side seal 530D is formed as viewed from the front. The lead portion 304D is bent along the upper surface of the battery element 100D. The lead portion 304D may not be bent. The shape of the bending of the lead portion 304D is not limited to the shape according to embodiment 4.

As shown in fig. 18, the outer film 300D has a front portion 310D, a rear portion 320D, and a central portion 330D. The front portion 310D is located around the periphery of the collecting portion of the positive electrode current collector 102aD in the X direction. Rear portion 320D is located around the periphery of the collecting portion of negative electrode current collector 104aD in the X direction. The central portion 330D is located between the front portion 310D and the rear portion 320D in the X-direction. The center 330D is located around the X-direction of the battery element 100D.

In the exterior film 300D, no wrinkles are present in the central portion 330D, but wrinkles are present in at least one of the front portion 310D and the rear portion 320D. In the shape of the exterior film 300D, wrinkles may be formed in the exterior film 300D due to the deformation. If wrinkles exist in the central portion 330D, the wrinkles may be transferred to the battery element 100D. As a result, the characteristics of the battery cell 10D are sometimes affected by the wrinkles. For example, in a portion where wrinkles are present, unevenness may occur in the interval between the positive electrode and the negative electrode, and the ion resistance may deviate. As another example, deterioration may be promoted in a portion where the resistance between the positive electrode and the negative electrode is relatively small due to non-uniformity in the interval between the positive electrode and the negative electrode, as compared with other portions. Sometimes it is difficult to remove the wrinkles themselves of the outer film 300D. In embodiment 4, even if the central portion 330D is creased, the creasing is moved toward at least one of the front portion 310D and the rear portion 320D. The wrinkles existing in the front portion 310D or the rear portion 320D hardly affect the characteristics of the battery cell 10D. Therefore, in embodiment 4, the characteristics of the battery cell 10D can be stabilized. Further, in embodiment 4, a space formed on the inner surface side of the front portion 310D or the rear portion 320D due to the wrinkles can be used as a space for accommodating an electrolyte solution or a space for accommodating a gas.

The wrinkles of the exterior film 300D may be generated by, for example, a difference between the size of the battery element 100D and the size of the front cover 210D or the rear cover 220D when viewed from the X direction.

In one example, the size of the front cover 210D may be larger than the size of the battery element 100D as viewed in the X direction. For example, the length of front cover 210D in the Y direction may be longer than the thickness of battery element 100D in the Y direction. For example, a plurality of battery cells 10D may be stacked in the Y direction to form a battery module. In this example, a compression pad may be disposed between the central portions 330D of the battery cells 10D adjacent in the Y direction. In this battery module, the length of the front cover 210D in the Y direction may be longer than the thickness of the battery element 100D in the Y direction by a corresponding amount corresponding to the thickness of the compression pad in the Y direction. This enables the plurality of battery cells 10D to be stably stacked in the Y direction. As in the example described above, the size of rear cover 220D may be larger than the size of battery element 100D as viewed in the X direction.

In other examples, the size of the front cover 210D may be smaller than the size of the battery element 100D as viewed from the X direction. For example, the length of front cover 210D in the Y direction may be shorter than the thickness of battery element 100D in the Y direction. For example, a plurality of battery cells 10D may be stacked in the Y direction to form a battery module. In this example, in the case where the length of the front cover 210D in the Y direction is shorter than the thickness of the battery element 100D in the Y direction, contact and interference of the front cover 210D adjacent in the Y direction can be suppressed. Further, the actual thickness of the battery element 100D in the Y direction may be smaller than the thickness of the battery element 100D in the Y direction due to the tolerance of the thickness of the battery element 100D in the Y direction. In this case, even when the length of the front cover 210D in the Y direction is shorter than the thickness of the battery element 100D in the Y direction, the plurality of battery cells 10D can be stably stacked in the Y direction to form the battery module.

Fig. 20 is a diagram for explaining example 1 of a method for manufacturing a battery cell 10D according to embodiment 4. In example 1, the battery cell 10D is manufactured as follows.

First, battery element 100D is manufactured. The battery element 100D has at least 1 positive electrode, at least 1 negative electrode, and at least 1 separator.

Next, the positive electrode tab 110D and the front cover 210D are joined to each other. Similarly, the negative electrode tab 120D and the rear cover 220D are joined to each other. Next, the positive electrode tab 110D and the positive electrode collector 102aD are bonded to each other. Similarly, the negative electrode tab 120D and the negative electrode collector 104aD are joined to each other. After the positive electrode tab 110D and the positive electrode collector 102aD are joined to each other, the positive electrode tab 110D and the front cover 210D may be joined to each other. Similarly, after the negative electrode tab 120D and the negative electrode collector 104aD are joined to each other, the negative electrode tab 120D and the rear cover 220D may be joined to each other.

Next, the exterior film 300D is wound around the battery element 100D, the front cover 210D, and the rear cover 220D in the X direction. Thereby, a winding portion 302D is formed around the battery element 100D, the front cover 210D, and the rear cover 220D in the X direction. Further, the excess length of the exterior film 300D is led out from the winding portion 302D as a lead-out portion 304D.

Next, the outer peripheral surface of the front cover 210D around the X direction and the inner peripheral surface of the opening in front of the wound portion 302D around the X direction are joined to each other by thermal welding. Thereby, the front seal portion 510D is formed. Next, the outer peripheral surface of the rear cover 220D around the X direction and the inner peripheral surface of the opening at the rear of the wound portion 302D around the X direction are joined to each other by thermal welding. Thereby, the rear seal 520D is formed.

Next, as shown in fig. 20, an electrolyte is injected into the storage space 500D through the injection opening 304 cD. The liquid filling opening 304cD is formed by a gap between the 1 st lead-out portion 304aD and the 2 nd lead-out portion 304 bD.

Next, the accommodating space 500D is vacuum sealed. Specifically, after the accommodating space 500D is evacuated through the liquid filling opening 304cD, the 1 st lead-out portion 304aD and the 2 nd lead-out portion 304bD are joined to each other by thermal fusion, so that the side seal 530D is formed. Sometimes, wrinkles are formed in the exterior film 300D by evacuating the housing space 500D. If the central portion 330D has wrinkles, the wrinkles are moved toward at least one of the front portion 310D and the rear portion 320D.

Next, the lead portion 304D is bent along the upper surface of the battery element 100D.

In this way, the battery cell 10D is manufactured.

Fig. 21 is a diagram for explaining example 2 of a method for manufacturing the battery cell 10D according to embodiment 4. The example 2 is the same as the example 1 described above, except for the following points.

First, battery element 100D was manufactured in the same manner as in example 1. Next, the positive electrode tab 110D and the front cover 210D are joined to each other in the same manner as in example 1. Further, the negative electrode tab 120D and the rear cover 220D are joined to each other. Next, the positive electrode tab 110D and the positive electrode current collector 102aD are bonded to each other in the same manner as in example 1. Further, the negative electrode tab 120D and the negative electrode collector 104aD are joined to each other.

Next, the exterior film 300D is wound around the battery element 100D, the front cover 210D, and the rear cover 220D in the X direction to form the winding portion 302D and the lead-out portion 304D. Next, the outer peripheral surface of the front cover 210D around the X direction and the inner peripheral surface of the opening in front of the wound portion 302D around the X direction are joined to each other by thermal welding. Thereby, the front seal portion 510D is formed. Next, the outer peripheral surface of the rear cover 220D around the X direction and the inner peripheral surface of the opening at the rear of the wound portion 302D around the X direction are joined to each other by thermal welding. Thereby, the rear seal 520D is formed. Next, the 1 st lead-out portion 304aD and the 2 nd lead-out portion 304bD are joined to each other by thermal fusion. Thereby, the side seal 530D is formed.

Next, as shown in fig. 21, an electrolyte is injected into the storage space 500D through the injection hole 210aD provided in the front cover 210D. Next, the accommodating space 500D is vacuum sealed. Specifically, after the accommodating space 500D is evacuated through the pour hole 210aD, the pour hole 210aD is closed by a predetermined lid member. Sometimes, wrinkles are formed in the exterior film 300D by evacuating the housing space 500D. If the central portion 330D has wrinkles, the wrinkles are moved toward at least one of the front portion 310D and the rear portion 320D. The filling hole may be provided in the rear cover 220D.

Next, as in example 1, the lead portion 304D is bent along the upper surface of the battery element 100D.

In this way, the battery cell 10D is manufactured.

Fig. 22 is a front perspective view of a battery cell 10D1 according to a modification. The battery cell 10D1 according to the modification is the same as the battery cell 10D according to embodiment 4, except for the following points.

In the modification, the positive electrode tab 110D1 is led out from the substantially center of the front cover 210D in the Y direction. The negative electrode tab 120D1 is led out from the substantially center of the rear cover in the Y direction. In the modification, a plurality of collecting portions of the positive electrode current collector are also present between the battery element and the positive electrode tab 110D 1. Similarly, a plurality of collector portions of the negative electrode collector are present between the battery element and the negative electrode tab 120D 1. In the modification, wrinkles of the exterior film 300D are also present around the gathered portions of the exterior film 300D. Therefore, in the modification, the characteristics of the battery cell 10D1 can be stabilized as in embodiment 4.

While embodiment 4 and the modification of the present invention have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can be adopted.

For example, in embodiment 4, the positive electrode tab 110D and the negative electrode tab 120D are disposed on opposite sides of the battery element 100D in the X direction. However, both the positive electrode tab 110D and the negative electrode tab 120D may be disposed on only one of the front side and the rear side in the X direction of the battery element 100D. In this case, the front end and the rear end of battery element 100D are covered with, for example, 2 covers. Alternatively, only the side of the battery element 100D from which the positive electrode tab 110D and the negative electrode tab 120D are drawn may be covered with a cover. In this example, the exterior film 300D may be sealed on the opposite side of the lid of the battery element 100D, and folded along the battery element 100D.

Embodiment 5

Embodiment 5 and a modification of the present invention will be described below with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof is omitted.

Fig. 23 is a front perspective view of battery cell 10E according to embodiment 5. Fig. 24 is a front enlarged perspective view of a part of battery cell 10E according to embodiment 5. Fig. 25 is a right side view of battery cell 10E according to embodiment 5. Fig. 25 illustrates a state where the exterior film 300E is penetrated for the sake of explanation.

In the drawings, for the sake of explanation, X direction, Y direction, and Z direction are labeled. The X direction indicates the front-rear direction of the battery cell 10E. The Y direction is orthogonal to the X direction. The Y direction represents the left-right direction of the battery cell 10E. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 10E. The direction pointed by the arrow representing the X direction, the direction pointed by the arrow representing the Y direction, and the direction pointed by the arrow representing the Z direction are the rear direction, the left direction, and the upper direction, respectively. The relationship among the X direction, Y direction, Z direction, front-rear direction, left-right direction, and up-down direction of the battery cell 10E is not limited to this example.

The battery cell 10E includes the battery element 100E, the positive electrode tab 110E, the negative electrode tab 120E, the front cover 210E, the rear cover 220E, the exterior film 300E, and the reinforcing plate 400E. The exterior film 300E has a winding portion 302E and a lead-out portion 304E.

The battery element 100E has a substantially rectangular parallelepiped shape. The longitudinal direction of battery element 100E is substantially parallel to the X direction. The length of the battery element 100E in the X direction is not limited to the following, but is, for example, 300mm to 500mm, preferably 450 mm. The short side direction of battery element 100E is substantially parallel to the Z direction. The length of battery element 100E in the Z direction is not limited to the following, but is, for example, 90mm to 130mm, preferably 120 mm. The thickness direction of battery element 100E is substantially parallel to the Y direction. The thickness of the battery element 100E in the Y direction is not limited to the following, and is, for example, 20mm to 50mm, preferably 45 mm. The shape of battery element 100E is not limited to this example.

The battery element 100E has at least 1 positive electrode not shown, at least 1 negative electrode not shown, and at least 1 separator not shown. For example, a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked in the Y direction. At least a part of the separator is located between the positive electrode and the negative electrode adjacent in the Y direction. For example, a plurality of sheet-like separators may be respectively located between the positive electrode and the negative electrode adjacent to each other in the Y direction. Alternatively, the separator may have a meandering shape with turns back on both sides in the Z direction, as viewed from the X direction. In this example, the portions of the separator between the folds on both sides in the Z direction are arranged between the positive electrode and the negative electrode adjacent in the Y direction. Alternatively, the positive electrode, the negative electrode, and the separator may be wound such that the separator is disposed between the positive electrode and the negative electrode. In one example, the positive electrode, the negative electrode, and the separator are wound in a state where one or both surfaces of the positive electrode and the negative electrode are covered with the separator. In other examples, a laminate including a plurality of unit laminates including the positive electrode, the separator, and the negative electrode in this order may be wound. However, the wound structure of the positive electrode, the negative electrode, and the separator is not limited to these examples.

As shown in fig. 25, positive electrode tab 110E is disposed in front of battery element 100E. The positive electrode tab 110E is electrically connected to the positive electrode current collector 102 aE. The positive electrode current collector 102aE is drawn forward from the positive electrode. Thus, the positive electrode tab 110E is electrically connected to the plurality of positive electrodes.

As shown in fig. 25, negative electrode tab 120E is disposed behind battery element 100E. The negative electrode tab 120E is electrically connected to the negative electrode current collector 104 aE. The negative electrode current collector 104aE is drawn from the negative electrode to the rear. Thus, the negative electrode tab 120E is electrically connected to the plurality of negative electrodes.

The front cover 210E covers the front end portion of the battery element 100E. The front cover 210E contains, for example, resin, metal, or the like. The front end portion of the positive electrode tab 110E protrudes from the front surface of the front cover 210E. The front cover 210E has a substantially rectangular shape when viewed from the front. The long side direction of the front cover 210E is substantially parallel to the Z direction, and the short side direction of the front cover 210E is substantially parallel to the Y direction, as viewed from the front.

The rear cover 220E covers the rear end of the battery element 100E. The rear cover 220E contains, for example, resin, metal, or the like. The rear end of the negative electrode tab 120E protrudes from the rear surface of the rear cover 220E. The rear cover 220E has a substantially rectangular shape when viewed from the rear. The long side direction of the rear cover 220E is substantially parallel to the Z direction, and the short side direction of the rear cover 220E is substantially parallel to the Y direction, as viewed from the rear.

As shown in fig. 23 and 24, the wound portion 302E has a substantially tubular shape that is open both forward and rearward. The front cover 210E is disposed inside the opening in front of the winding portion 302E. The rear cover 220E is disposed inside the opening at the rear of the winding portion 302E. The winding portion 302E is wound around the battery element 100E, the front cover 210E, and the rear cover 220E for 1 week in the X direction. Thus, the front cover 210E, the rear cover 220E, and the winding portion 302E form a housing space 500E that houses the battery element 100E. In the housing space 500E, an electrolyte solution, not shown, is housed together with the battery element 100E. In addition, the manner of winding the battery element 100E of the winding portion 302E is not limited to the above-described example.

An outer peripheral surface of the front cover 210E around the X direction and an inner peripheral surface of the opening in front of the wound portion 302E around the X direction are joined to each other by, for example, thermal welding. Thereby, the front seal portion 510E is formed.

An outer peripheral surface of the rear cover 220E around the X direction and an inner peripheral surface of the opening at the rear of the wound portion 302E around the X direction are joined to each other by, for example, thermal welding. Thereby, the rear seal 520E is formed.

As shown in fig. 23 and 24, the lead-out portion 304E is led out from the corner of the upper left side of the battery element 100E of the winding portion 302E, as viewed from the front. Specifically, as shown in fig. 24, the lead-out portion 304E includes a 1 st lead-out portion 304aE and a 2 nd lead-out portion 304bE. The 1 st lead-out portion 304aE is led out from one of both ends of the winding portion 302E around the circumferential direction in the X direction. The 2 nd lead-out portion 304bE is led out from the other of the two ends of the winding portion 302E around the circumferential direction in the X direction. The 1 st lead-out portion 304aE and the 2 nd lead-out portion 304bE are bonded to each other by, for example, thermal fusion. Thereby, the side seal 530E is formed as viewed from the front. The lead portion 304E is bent along the upper surface of the battery element 100E. The lead portion 304E may not be bent. The shape of the bending of the lead portion 304E is not limited to the shape according to embodiment 5.

As shown in fig. 23 to 25, the reinforcing plate 400E is disposed above the lead portion 304E. Reinforcing plate 400E is provided along the longitudinal direction of the upper surface of battery element 100E. Thereby, reinforcing plate 400E can function as a reinforcing member for reinforcing the strength of battery element 100E in the X direction. Therefore, in embodiment 5, the strength of the battery cell 10E in the longitudinal direction can be ensured as compared with the case where the reinforcing plate 400E is not provided in the air hole. The position where the reinforcing plate 400E is disposed is not limited to the examples shown in fig. 23 to 25. For example, the reinforcement plate 400E may be disposed along at least a portion of the lower surface, the left side surface, and the right side surface of the battery element 100E.

The front end of the reinforcement plate 400E is joined to the front cover 210E by, for example, laser welding. The rear end of the reinforcement plate 400E is joined with the rear cover 220E, for example, by laser welding. The rigidity of each of front cover 210E, rear cover 220E, and reinforcing plate 400E is higher than the rigidity of battery element 100E. Therefore, in embodiment 5, the strength of the battery element 100E can be reinforced from at least 3 directions by the front cover 210E, the rear cover 220E, and the reinforcing plate 400E.

The reinforcement plate 400E may not be engaged with the front cover 210E and the rear cover 220E. Alternatively, the reinforcement plate 400E may be joined to only one of the front cover 210E and the rear cover 220E.

Next, an example of a method for manufacturing the battery cell 10 according to embodiment 5 will be described. In this example, the battery cell 10E is manufactured as follows.

First, battery element 100E is manufactured. The battery element 100E has at least 1 positive electrode, at least 1 negative electrode, and at least 1 separator.

Next, the positive electrode tab 110E and the front cover 210E are joined to each other. Similarly, the negative electrode tab 120E and the rear cover 220E are joined to each other. Next, the positive electrode tab 110E and the positive electrode collector 102aE are bonded to each other. Similarly, the negative electrode tab 120E and the negative electrode collector 104aE are joined to each other. After the positive electrode tab 110E and the positive electrode collector 102aE are joined to each other, the positive electrode tab 110E and the front cover 210E may be joined to each other. Similarly, after the negative electrode tab 120E and the negative electrode collector 104aE are joined to each other, the negative electrode tab 120E and the rear cover 220E may be joined to each other.

Next, the exterior film 300E is wound around the battery element 100E, the front cover 210E, and the rear cover 220E for 1 week in the X direction. Thereby, the winding portion 302E is formed. The excess length of the exterior film 300E is drawn out as a drawn-out portion 304E.

Next, the outer peripheral surface of the front cover 210E around the X direction and the inner peripheral surface of the opening in front of the wound portion 302E around the X direction are joined to each other by thermal welding. Thereby, the front seal portion 510E is formed. Next, the outer peripheral surface of the rear cover 220E around the X direction and the inner peripheral surface of the opening at the rear of the wound portion 302E around the X direction are joined to each other by thermal welding. Thereby, the rear seal 520E is formed.

Next, the electrolyte is injected into the accommodating space 500E through the gap between the 1 st lead-out portion 304aE and the 2 nd lead-out portion 304 bE. Then, the accommodating space 500E is evacuated through the gap between the 1 st lead-out portion 304aE and the 2 nd lead-out portion 304 bE. Next, the 1 st lead portion 304aE and the 2 nd lead portion 304bE are joined by thermal fusion, thereby forming the side seal 530E. Thereby, the accommodating space 500E is vacuum sealed.

The method of vacuum sealing the housing space 500E is not limited to the above example. In other examples, first, the 1 st lead portion 304aE and the 2 nd lead portion 304bE are joined by thermal fusion, to form the side seal 530E. Next, the electrolyte is injected into the storage space 500E through the injection hole provided in at least one of the front cover 210E and the rear cover 220E. Then, the accommodating space 500E is evacuated through the filling hole. The filling hole is then blocked by a given cap.

Next, the lead portion 304E is bent along the upper surface of the battery element 100E.

Next, the reinforcing plate 400E is mounted above the lead-out portion 304E.

In this way, the battery cell 10E is manufactured

Fig. 26 is a diagram showing a battery cell 10E1 according to a modification. The battery cell 10E1 according to the modification is the same as the battery cell 10E according to embodiment 5, except for the following points.

The exterior film 300E1 of the battery cell 10E1 according to the modification has a winding portion 302E1 and a lead-out portion 304E1. The winding portion 302E1 according to the modification is wound around the battery element 100E, the front cover 210E, and the rear cover 220E in the X direction by 1 week, similarly to the winding portion 302E according to embodiment 5. The lead portion 304E1 according to the modification is led out from the wound portion 302E1 in the same manner as the lead portion 304E according to embodiment 5.

In the example shown in fig. 26, the lead portion 304E1 is bent 2 times as viewed from the X direction. Specifically, the base end portion of the lead portion 304E1 is bent from the upper side to the right side in the vicinity of the upper left corner of the front cover 210E as viewed from the X direction. Further, the substantially central portion of the lead portion 304E1 is bent from the right to the left above the front cover 210E as viewed in the X direction. Therefore, compared with the case where the lead-out portion 304E1 is simply led out, the rigidity of the lead-out portion 304E1 in the X direction can be improved. Therefore, the lead portion 304E1 can function as a reinforcement member that reinforces the strength of the battery element 100E in the X direction. Therefore, in the modification, the strength of the battery cell 10E1 in the longitudinal direction can be ensured as compared with the case where the lead-out portion 304E1 is simply led out.

In the example shown in fig. 26, the front end of the lead-out portion 304E1 is folded in toward the inside of the lead-out portion 304E1 as viewed from the X direction. Therefore, the tip of the lead portion 304E1 can be prevented from being exposed to the outside of the lead portion 304E 1. For example, the lead portion 304E1 may have a conductor such as a conductive sheet. Sometimes the conductor is exposed from the front end of the lead-out portion 304E 1. In the example shown in fig. 26, the conductor exposed from the front end of the lead-out portion 304E1 can be prevented from being exposed to the outside of the lead-out portion 304E 1. Therefore, a short circuit through the outer film 300E1 of the conductor can be suppressed.

The manner of bending the lead portion 304E1 is not limited to the example shown in fig. 26. For example, the lead portion 304E1 may be bent 3 times or more as viewed in the X direction. That is, the drawn portion 304E1 can be bent a plurality of times as viewed from the X direction.

In the modification, similarly to embodiment 5, a reinforcing plate 400E may be further provided. In this case, both the lead portion 304E1 and the reinforcing plate 400E can function as a reinforcing member for reinforcing the strength of the battery element 100E in the X direction.

While embodiment 5 and the modification of the present invention have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above may be employed.

For example, in embodiment 5, the reinforcing plate 400E is provided outside the exterior film 300E. However, the reinforcing plate 400E may be provided inside the exterior film 300E.

In embodiment 5, the positive electrode tab 110E and the negative electrode tab 120E are disposed on opposite sides of the battery element 100E in the X direction. However, both the positive electrode tab 110E and the negative electrode tab 120E may be disposed on only one of the front side and the rear side in the X direction of the battery element 100E. In this case, the front end and the rear end of battery element 100E are covered with, for example, 2 covers. Alternatively, only the side of the battery element 100E from which the positive electrode tab 110E and the negative electrode tab 120E are drawn may be covered with a cover. In this example, the exterior film 300E may be sealed on the opposite side of the lid of the battery element 100E and folded along the battery element 100E.

Claims

1. A battery cell is provided with:

a battery element;

a cover member covering one end of the battery element in a predetermined direction; and

an exterior film, at least a portion of which is wound around the given direction at the battery element,

the outer film has rounded corners along the battery element at least 1 corner of the battery element around the given direction.

2. The battery cell according to claim 1, wherein,

the corners of the cover, which are juxtaposed in the given direction with the at least 1 corner of the battery element, are rounded.

3. The battery cell according to claim 1 or 2, wherein,

at least 1 corner of the battery element in the exterior film around the given direction is provided with a fold line.

4. The battery cell according to claim 1 or 2, wherein,

the battery cell further comprises: and a cover member covering the other end of the battery element in the predetermined direction.

5. A battery cell is provided with:

a battery element;

a cover member that covers an end portion of the battery element; and

an exterior film having a winding portion wound around the battery element and a lead-out portion led out from the winding portion,

at least a part of the winding portion and at least a part of the lead-out portion are engaged with each other.

6. The battery cell according to claim 5, wherein,

the engaging portions of the winding portion and the lead-out portion overlap at least a part of a surface of the battery element facing in a given direction.

7. The battery cell according to claim 5, wherein,

The battery element has: a given length in the 1 st direction between the end portion and the other end portion on the opposite side of the end portion; a width in a 2 nd direction orthogonal to the 1 st direction; and a thickness in a 3 rd direction shorter than the width and orthogonal to the 1 st direction and the 2 nd direction,

the junction of the winding portion and the lead portion overlaps at least a part of a surface of the battery element that is substantially perpendicular to the 3 rd direction.

8. The battery cell according to claim 5, wherein,

the junction of the winding portion and the lead portion overlaps at least a part of a surface of the battery element that is substantially perpendicular to the 2 nd direction.

9. The battery cell according to any one of claims 5 to 8, wherein,

the junction of the winding portion and the lead-out portion is located at an arbitrary portion other than a portion below the periphery of the battery element.

10. A battery cell is provided with:

a battery element;

a cover member that covers an end portion of the battery element in the longitudinal direction;

an exterior film at least a part of which is wound around the battery element in the longitudinal direction; and

and a reinforcing body provided along the longitudinal direction of the battery element.

11. The battery cell according to claim 10, wherein,

one end of the reinforcing body in the longitudinal direction is engaged with the cover member.

12. The battery cell according to claim 10 or 11, wherein,

at least one part of the reinforcing body is provided with a lead-out part of the outer coating film which is bent for a plurality of times.