JP2024021614A - battery cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the thickness of a lid material in the state of securing the strength of the lid material.

SOLUTION: A battery cell 10 comprises: a battery element 100; a front lid material 210 for covering one end of the battery element 100; an outer packaging film 300 that is at least partially wound around the battery element 100; and a rib 212 that is provided in the front lid material 210.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to battery cells.

In recent years, various structures of battery cells such as lithium ion secondary battery cells have been developed. For example, the battery cell described in Patent Document 1 includes a battery element, two lid members, and an exterior film. The two lids cover both longitudinal ends of the battery element. The outer film is wrapped around the length of the battery element.

Japanese Patent Application Publication No. 2011-108623

Due to certain demands such as improving volumetric energy density, the thickness of the lid material may be reduced. However, if the thickness of the lid material is simply reduced, it may be difficult to ensure the strength of the lid material.

An example of an object of the present invention is to reduce the thickness of a lid material while maintaining the strength of the lid material. Other objects of the invention will become apparent from the description herein.

One aspect of the present invention is as follows.
[1]
battery element;
a lid material that covers one end of the battery element;
an exterior film at least partially wrapped around the battery element;
Ribs provided on the lid material;
A battery cell comprising:
[2]
The battery cell according to [1], wherein at least a portion of the rib defines a space communicating with an accommodation space formed by the lid material and the exterior film.
[3]
further comprising a current collector drawn out from the battery element,
[1] or [2], wherein the height of the rib in a region that does not overlap with the current collector in the protruding direction of the rib is higher than the height of the rib in a region that overlaps with the current collector in the protruding direction of the rib; ] The battery cell described in .
[4]
further comprising a current collector drawn out from the battery element,
The rib is provided in a region that does not overlap with the current collector in the protruding direction of the rib,
The battery cell according to [1] or [2], wherein the rib is not provided in a region overlapping with the current collector in the protruding direction of the rib.
[5]
It has a folding part that is folded inside the lid material, and a folding part that is folded with respect to the folding part, and further includes a current collector pulled out from the battery element,
The height of the rib in a region overlapping with the folded portion of the current collector in the protruding direction of the rib is higher than the height of the rib in a region overlapping with the folded portion of the current collector in the protruding direction of the rib. , [1] or the battery cell according to [2].
[6]
It has a folding part that is folded inside the lid material, and a folding part that is folded with respect to the folding part, and further includes a current collector pulled out from the battery element,
The rib is provided in a region that overlaps with the folded portion of the current collector in the protruding direction of the rib,
The battery cell according to [1] or [2], wherein the rib is not provided in a region that overlaps with the bent portion of the current collector in the protruding direction of the rib.

According to the above aspect of the present invention, the thickness of the lid material can be reduced while maintaining the strength of the lid material.

FIG. 2 is a front perspective view of a battery cell according to an embodiment. FIG. 2 is an enlarged front perspective view of a portion of the battery cell according to the embodiment. FIG. 2 is a right side view of a battery cell according to an embodiment. FIG. 3 is a rear view of the front lid material according to the embodiment. 3 is a side view of a portion of a battery cell according to modification 1. FIG. FIG. 7 is a rear view of the front lid material according to Modification Example 1; 7 is a side view of a portion of a battery cell according to modification 2. FIG.

Embodiments and modifications of the present invention will be described below with reference to the drawings. In all the drawings, similar components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

FIG. 1 is a front perspective view of a battery cell 10 according to an embodiment. FIG. 2 is an enlarged front perspective view of a portion of the battery cell 10 according to the embodiment. FIG. 3 is a right side view of the battery cell 10 according to the embodiment. In FIG. 3, for the sake of explanation, the exterior film 300 is shown in a transparent state.

Each figure is labeled with an X direction, a Y direction, and a Z direction for explanation. The X direction indicates the front-rear direction of the battery cell 10. The Y direction is perpendicular to the X direction. The Y direction indicates the left and right direction of the battery cell 10. The Z direction is perpendicular to both the X direction and the Y direction. The Z direction indicates the vertical direction of the battery cell 10. The direction indicated by the arrow indicating the X direction, the direction indicated by the arrow indicating the Y direction, and the direction indicated by the arrow indicating the Z direction are backward, leftward, and upward, respectively. However, the relationship of the battery cell 10 in the X direction, Y direction, Z direction, front and back direction, left and right direction, and up and down direction is not limited to this example.

Note that a white circle with an X indicating the X direction, Y direction, or Z direction indicates that the direction from the front to the back of the page is the direction indicated by the arrow indicating the direction. A white circle with a black dot indicating the X direction, Y direction, or Z direction indicates that the direction from the back of the page to the front is the direction indicated by the arrow indicating the direction.

The battery cell 10 includes a battery element 100, a positive electrode tab 110, a negative electrode tab 120, a front lid material 210, a rear lid material 220, and an exterior film 300. The exterior film 300 has a wrap portion 302 and a pull-out portion 304.

The battery element 100 has a substantially rectangular parallelepiped shape. The longitudinal direction of the battery element 100 is approximately parallel to the X direction. The length of the battery element 100 in the X direction is, for example, not less than 300 mm and not more than 500 mm, preferably not more than 450 mm, although it is not limited to the following. The lateral direction of the battery element 100 is approximately parallel to the Z direction. Although the length of the battery element 100 in the Z direction is not limited to the following, for example, it is 90 mm or more and 130 mm or less, preferably 120 mm or less. The thickness direction of the battery element 100 is approximately parallel to the Y direction. Although the thickness of the battery element 100 in the Y direction is not limited to the following, for example, it is 20 mm or more and 50 mm or less, preferably 45 mm or less. However, the shape of battery element 100 is not limited to this example.

The battery element 100 has at least one positive electrode (not shown), at least one negative electrode (not shown), and at least one 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 portion of the separator is located between a positive electrode and a negative electrode adjacent in the Y direction. For example, each of a plurality of sheet-like separators may be located between a positive electrode and a negative electrode adjacent to each other in the Y direction. Alternatively, the meander-shaped separators may be alternately folded back and forth at both ends in the Z direction. In this example, a portion of the separator located between both ends in the Z direction is arranged between a positive electrode and a negative electrode adjacent in the Y direction. Alternatively, the positive electrode, negative electrode, and 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 so that both surfaces of one of the positive electrode and the negative electrode are covered with the separator. In another example, a laminate including a plurality of unit laminates including a positive electrode, a separator, and a negative electrode in this order may be wound. However, the winding structures of the positive electrode, negative electrode, and separator are not limited to these examples.

As shown in FIG. 3, the positive electrode tab 110 is arranged in front of the battery element 100. The positive electrode tab 110 is electrically connected to the positive electrode current collector 102a. The positive electrode current collector 102a is drawn out from the positive electrode of the battery element 100 toward the front. Thereby, the positive electrode tab 110 is electrically connected to the plurality of positive electrodes of the battery element 100.

As shown in FIG. 3, the negative electrode tab 120 is arranged at the rear of the battery element 100. Negative electrode tab 120 is electrically connected to negative electrode current collector 104a. The negative electrode current collector 104a is drawn out from the negative electrode of the battery element 100 toward the rear. Thereby, the negative electrode tab 120 is electrically connected to the plurality of negative electrodes of the battery element 100.

The front lid member 210 covers the front end of the battery element 100. The front lid member 210 is made of, for example, resin, metal, or the like. The front end of the positive electrode tab 110 protrudes from the front surface of the front lid member 210. When viewed from the front, the front lid member 210 has a substantially rectangular shape. When viewed from the front, the longitudinal direction of the front lid 210 is approximately parallel to the Z direction, and the lateral direction of the front lid 210 is approximately parallel to the Y direction.

The rear lid member 220 covers the rear end of the battery element 100. The rear lid material 220 is made of, for example, resin, metal, or the like. A rear end portion of the negative electrode tab 120 protrudes from the rear surface of the rear lid member 220. When viewed from the rear, the rear lid member 220 has a substantially rectangular shape. When viewed from the rear, the longitudinal direction of the rear lid 220 is approximately parallel to the Z direction, and the lateral direction of the rear lid 220 is approximately parallel to the Y direction.

As shown in FIGS. 1 and 2, the wrapped portion 302 has a substantially cylindrical shape that is open toward both the front and the rear. A front lid member 210 is disposed inside the front opening of the wrapped portion 302. A rear lid member 220 is disposed inside the rear opening of the wrapped portion 302. The wrapped portion 302 is wound once around the battery element 100, the front cover member 210, and the rear cover member 220 in the X direction. Thereby, the front cover material 210, the rear cover material 220, and the wrapped portion 302 form a housing space 500 that accommodates the battery element 100. The housing space 500 accommodates an electrolytic solution (not shown) together with the battery element 100. Note that the manner in which the battery element 100 is wound around the winding portion 302 is not limited to the example described above.

The outer peripheral surface of the front lid member 210 around the X direction and the inner peripheral surface of the front opening of the wrapped portion 302 around the X direction are joined to each other by, for example, heat fusion. As a result, a front sealing portion 510 is formed.

The outer peripheral surface of the rear lid member 220 around the X direction and the inner peripheral surface of the rear opening of the wrapped portion 302 around the X direction are joined to each other by, for example, heat fusion. As a result, a rear sealing portion 520 is formed.

As shown in FIGS. 1 and 2, the pull-out portion 304 is pulled out from the upper left corner of the battery element 100 of the wrapped portion 302 when viewed from the front. Specifically, as shown in FIG. 2, the drawer portion 304 includes a first drawer portion 304a and a second drawer portion 304b. The first drawn-out portion 304a is drawn out from one of both ends of the wrapped portion 302 in the circumferential direction around the X direction. The second drawn-out portion 304b is drawn out from the other of both ends of the wrapped portion 302 in the circumferential direction around the X direction. The first drawer portion 304a and the second drawer portion 304b are joined to each other by, for example, heat fusion. As a result, a side sealing portion 530 is formed when viewed from the front. The drawer portion 304 is bent along the top surface of the battery element 100. However, the drawer portion 304 does not have to be bent. Further, the shape of the folded portion 304 is not limited to the shape according to the embodiment.

FIG. 4 is a rear view of the front lid member 210 according to the embodiment. The front lid member 210 will be described with reference to FIG. 4 and, if necessary, FIGS. 1 to 3.

The front lid member 210 is provided with a front notch 210a. The positive electrode tab 110 passes through the front notch 210a and is pulled out from the front lid member 210 toward the front. Note that the position where the front notch 210a is provided is not limited to the example shown in FIG. 4.

A rib 212 is provided on the rear surface of the front lid member 210. The ribs 212 protrude rearward from the rear surface of the front lid member 210. The ribs 212 can function as a reinforcing member that reinforces the strength of the front lid member 210. Therefore, in the embodiment, the thickness of the front lid member 210 in the X direction can be reduced while maintaining the strength of the front lid member 210, compared to a case where the ribs 212 are not provided.

In the example shown in FIG. 4, the ribs 212 extend in a substantially square grid frame shape when viewed from the X direction. Therefore, a space 212a is defined in the area surrounded by each frame of the rib 212 when viewed from the X direction. Space 212a communicates with accommodation space 500. Therefore, the space 212a can accommodate excess electrolyte. Therefore, deterioration in the performance of the battery cell 10 due to depletion of the electrolyte can be easily suppressed. Therefore, the life of the battery cell 10 can be extended. Alternatively, at least a portion of the positive electrode current collector 102a can be accommodated in the space 212a.

The position where the rib 212 is provided is not limited to the example shown in FIG. 4. The rib 212 may be provided on the front surface of the front lid member 210, for example. Further, the shape of the rib 212 when viewed from the X direction is not limited to the example shown in FIG. 4 .

The rear lid material 220 can also be provided with ribs in the same way as the front lid material 210.

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

First, the battery element 100 is manufactured. Battery element 100 has at least one positive electrode, at least one negative electrode, and at least one separator.

Next, the positive electrode tab 110 and the front lid member 210 are joined to each other. Similarly, the negative electrode tab 120 and the rear lid material 220 are joined to each other. Next, the positive electrode tab 110 and the positive electrode current collector 102a are joined to each other. Similarly, the negative electrode tab 120 and the negative electrode current collector 104a are bonded to each other. However, after the positive electrode tab 110 and the positive electrode current collector 102a are joined to each other, the positive electrode tab 110 and the front cover material 210 may be joined to each other. Similarly, after the negative electrode tab 120 and the negative electrode current collector 104a are bonded to each other, the negative electrode tab 120 and the rear cover material 220 may be bonded to each other.

Next, the exterior film 300 is wrapped once around the battery element 100, the front lid material 210, and the rear lid material 220 in the X direction. As a result, a wrapped portion 302 is formed. Further, the extra length of the exterior film 300 is pulled out as a pull-out portion 304.

Next, the outer peripheral surface of the front lid member 210 around the X direction and the inner peripheral surface of the front opening of the wrapped portion 302 around the X direction are joined to each other by heat fusion. As a result, a front sealing portion 510 is formed. Next, the outer peripheral surface of the rear lid member 220 around the X direction and the inner peripheral surface of the rear opening of the wrapped portion 302 around the X direction are joined to each other by heat fusion. As a result, a rear sealing portion 520 is formed.

Next, the electrolytic solution is injected into the accommodation space 500 through the gap between the first drawn-out part 304a and the second drawn-out part 304b. Next, the accommodation space 500 is evacuated through the gap between the first drawer portion 304a and the second drawer portion 304b. Next, the first drawer portion 304a and the second drawer portion 304b are joined by heat fusion to form the side sealing portion 530. Thereby, the accommodation space 500 is vacuum sealed.

Note that the method of vacuum sealing the accommodation space 500 is not limited to the example described above. In another example, first, the first drawer portion 304a and the second drawer portion 304b are joined by heat fusion to form the side sealing portion 530. Next, the electrolytic solution is injected into the housing space 500 through a liquid injection hole provided in at least one of the front cover member 210 and the rear cover member 220. Next, the accommodation space 500 is evacuated through the liquid injection hole. Next, the liquid injection hole is closed with a predetermined lid material.

Next, the side sealing portion 530 is bent along the top surface of the battery element 100.

In this way, the battery cell 10 is manufactured.

FIG. 5 is a side view of a portion of a battery cell 10A according to modification 1. FIG. 6 is a rear view of a front lid member 210A according to Modification 1. In FIG. 5, a portion of the front lid member 210A is shown transparent for explanation. In FIG. 5, the exterior film is not illustrated for simplicity of explanation. In FIG. 6, the rib 212A is not illustrated for the sake of explanation. The battery cell 10A according to Modification 1 is the same as the battery cell 10 according to the embodiment except for the following points. The matters described using FIGS. 5 and 6 can be similarly applied to the rear cover material and the negative electrode tab.

As shown in FIG. 5, the front ends of the plurality of positive electrode current collectors 102aA and the rear ends of the positive electrode tabs 110A are joined to each other. The plurality of positive electrode current collectors 102aA are drawn out from the battery element 100A toward the front. The plurality of positive electrode current collectors 102aA are folded inside the front cover member 210A so as to overlap with the battery element 100A in the X direction. The front ends of the plurality of positive electrode current collectors 102aA are substantially parallel to the Y direction. The front end of the positive electrode tab 110A is pulled out forward through the front notch 210aA of the front lid member 210A. The rear end portion of the positive electrode tab 110A is bent at a predetermined angle inside the front lid member 210A with respect to the front end portion of the positive electrode tab 110A. Specifically, the rear end portion of the positive electrode tab 110A is bent at a substantially right angle to the front end portion of the positive electrode tab 110A inside the front cover member 210A when viewed from the Z direction. As a result, the rear end portion of the positive electrode tab 110A is substantially parallel to the Y direction. In Modified Example 1, the front lid member 210A is more parallel to the can be made thinner. Therefore, in Modification 1, the volumetric energy density of the battery cell 10A is improved compared to when the positive electrode current collector 102aA is not folded or when the rear end of the positive electrode tab 110A is substantially parallel to the X direction. You can make it easier to do so.

As shown in FIG. 5, the protruding direction of the rib 212A inside the front lid member 210A is substantially parallel to the X direction. The height of the rib 212A inside the front lid 210A in the X direction may vary depending on the position inside the front lid 210A. For example, as shown in FIG. 6, the front lid member 210A has a central region 211aA and two side regions 211bA. The central region 211aA overlaps the plurality of positive electrode current collectors 102aA and the positive electrode tab 110A in the X direction. The two side regions 211bA are located on both sides of the central region 211aA in the Z direction. Each side region 211bA does not overlap with the plurality of positive electrode current collectors 102aA and the positive electrode tab 110A in the X direction. The height of the rib 212A in the X direction in each side region 211bA may be higher than the height in the X direction of the rib 212A in the central region 211aA. In this case, the rib 212A may not be provided in the central region 211aA, but the rib 212A may be provided in each side region 211bA. Thereby, in the central region 211aA, the rib 212A can be prevented from interfering with the plurality of positive electrode current collectors 102aA and the positive electrode tab 110A. Further, in each side region 211bA, the height of the rib 212A in the X direction can be ensured.

Also in the first modification, at least a portion of the rib 212A may define a space that communicates with the accommodation space in which the battery element 100A is accommodated.

In Modification 1, a plurality of positive electrode current collectors 102aA are folded in a region overlapping with the central region 211aA in the X direction. However, in a region overlapping with the central region 211aA in the X direction, the plurality of positive electrode current collectors 102aA may not be folded but may simply be drawn out toward the front. Also in this example, the height of the rib 212A in the X direction in each side region 211bA may be higher than the height in the X direction of the rib 212A in the central region 211aA. In this case, the rib 212A may not be provided in the central region 211aA, but the rib 212A may be provided in each side region 211bA. Thereby, in the central region 211aA, the rib 212A can be prevented from interfering with the plurality of positive electrode current collectors 102aA and the positive electrode tab 110A. Further, in each side region 211bA, the height of the rib 212A in the X direction can be ensured.

FIG. 7 is a side view of a portion of a battery cell 10B according to a second modification. In FIG. 7, a portion of the front lid member 210B is shown for explanation. In FIG. 7, the exterior film is not illustrated for simplicity of explanation. The battery cell 10B according to the second modification is the same as the battery cell 10A according to the first modification except for the following points. The matters described using FIG. 7 can be similarly applied to the rear cover material and the negative electrode tab.

As shown in FIG. 7, the front ends of the plurality of positive electrode current collectors 102aB and the rear ends of the positive electrode tabs 110B are joined to each other. The plurality of positive electrode current collectors 102aB are drawn out toward the front from the battery element 100B. The plurality of positive electrode current collectors 102aB are folded inside the front lid member 210B so as to overlap with the battery element 100B in the X direction. The front end portions of the plurality of positive electrode current collectors 102aB are bent at a predetermined angle with respect to the folded portions of the plurality of positive electrode current collectors 102aB. Specifically, the front end portions of the plurality of positive electrode current collectors 102aB are bent at a substantially right angle to the folded portions of the plurality of positive electrode current collectors 102aB inside the front lid member 210B when viewed from the Z direction. It has become a department. As a result, the front ends of the plurality of positive electrode current collectors 102aB are substantially parallel to the X direction. The front end of the positive electrode tab 110B is pulled out forward through the front notch of the front lid member 210B. The rear end portion of the positive electrode tab 110B is not bent inside the front lid member 210A and is substantially parallel to the X direction. In Modification 2, the thickness of the front lid member 210B in the X direction can be made thinner than when the positive electrode current collector 102aB is not folded. Therefore, in Modification 2, the volumetric energy density of the battery cell 10B can be improved more easily than when the positive electrode current collector 102aB is not folded.

As shown in FIG. 7, the height of the rib 212B in the X direction may vary depending on the shape of the plurality of positive electrode current collectors 102aB. In the example shown in FIG. 7, the height in the X direction of the rib 212B that overlaps the folded portion of the plurality of positive electrode current collectors 102aB in the It is higher than the height in the X direction of the ribs 212B that overlap in the X direction. In this case, ribs 212B are not provided in the region that overlaps in the X direction with the folded portions of the plurality of positive electrode current collectors 102aB, but ribs 212B are provided in the region that overlaps in the X direction with the folded portions of the plurality of cathode current collectors 102aB. It may be. As a result, the ribs 212B can be prevented from interfering with the front end portions of the plurality of positive electrode current collectors 102aB in the region overlapping the bent portions of the plurality of positive electrode current collectors 102aB in the X direction. Further, in the region overlapping in the X direction with the folded portions of the plurality of positive electrode current collectors 102aB, the height of the rib 212B in the X direction can be ensured.

Also in the second modification, at least a portion of the rib 212B may define a space that communicates with the accommodation space in which the battery element 100B is accommodated.

Although the embodiments and modified examples of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above may also be adopted.

In the embodiment, the positive electrode tab 110 and the negative electrode tab 120 are arranged on opposite sides of the battery element 100 in the X direction. However, both the positive electrode tab 110 and the negative electrode tab 120 may be arranged only on one of the front side and the rear side of the battery element 100 in the X direction. In this case, the front end and rear end of the battery element 100 are covered by, for example, two lids. Alternatively, only the side of the battery element 100 from which the positive electrode tab 110 and the negative electrode tab 120 are pulled out may be covered with the lid material. In this example, the exterior film 300 may be sealed and folded along the battery element 100 on the opposite side of the lid material of the battery element 100.

10, 10A, 10B Battery cells 100, 100A, 100B Battery elements 102a, 102aA, 102aB Positive electrode current collector 104a Negative electrode current collector 110, 110A, 110B Positive electrode tab 120 Negative electrode tab 210, 210A, 210B Front cover material 210a, 210aA Front Notch 211aA Central region 211bA Side regions 212, 212A, 212B Rib 212a Space 220 Rear lid material 300 Exterior film 302 Wrapping portion 304 Drawer portion 304a First drawer portion 304b Second drawer portion 500 Accommodation space 510 Front sealing portion 520 Rear sealing section 530 Side sealing section

Claims (6)

battery element;
a lid material that covers one end of the battery element;
an exterior film at least partially wrapped around the battery element;
Ribs provided on the lid material;
A battery cell comprising: The battery cell according to claim 1, wherein at least a portion of the rib defines a space communicating with an accommodation space formed by the lid material and the exterior film. further comprising a current collector drawn out from the battery element,
3. The height of the rib in a region that does not overlap with the current collector in the protruding direction of the rib is higher than the height of the rib in a region that overlaps with the current collector in the protruding direction of the rib. The battery cell described. further comprising a current collector drawn out from the battery element,
The rib is provided in a region that does not overlap with the current collector in the protruding direction of the rib,
The battery cell according to claim 1 or 2, wherein the rib is not provided in a region overlapping with the current collector in the protruding direction of the rib. It has a folding part folded inside the lid material and a folding part folded with respect to the folding part, further comprising a current collector pulled out from the battery element,
The height of the rib in a region overlapping with the folded portion of the current collector in the protruding direction of the rib is higher than the height of the rib in a region overlapping with the folded portion of the current collector in the protruding direction of the rib. , the battery cell according to claim 1 or 2. It has a folding part folded inside the lid material and a folding part folded with respect to the folding part, further comprising a current collector pulled out from the battery element,
The rib is provided in a region that overlaps with the folded portion of the current collector in the protruding direction of the rib,
The battery cell according to claim 1 or 2, wherein the rib is not provided in a region that overlaps with the bent portion of the current collector in the protruding direction of the rib.

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