Battery module

Abstract

The utility model provides a battery module, which is provided with a plurality of stacked battery units and insulating parts for alternately fixing the plurality of battery units, the insulating parts comprise a first insulator and a second insulator which is more easily deformed than the first insulator, and before the swelling amount of the plurality of battery units reaches a specified amount, the second insulator is fixed on the first insulator. The insulating member disposed between the battery cells is pressed in the radial direction and deforms in the radial direction, and when the swell amount of the plurality of battery cells reaches a predetermined amount, the deformation of the insulating member in the radial direction is stopped, and when the swell amount of the plurality of battery cells reaches a predetermined amount, the deformation of the insulating member in the radial direction is reduced. The deformation of the plurality of battery cells is suppressed by the elastic force in the extending direction of the insulating member, and the movement of the plurality of battery cells is suppressed. As a result, the occurrence of defects associated with the expansion of the battery cell can be suppressed.

Description

Technical Field

[0001] The present utility model relates to a battery module. Background Art

[0002] In recent years, a battery pack formed by stacking a plurality of battery cells to form a battery module and housing the battery module has been used in vehicles and the like. Patent Document 1 describes a structure in which an elastomer is provided at the central portion of the battery cell to relieve the stress concentration caused by the expansion of the central portion of the battery cell.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-61210

[0004] In addition, as a related art, a mechanism for making the length of a bus bar adjustable is known. Here, when the bus bar is arranged in a state fixed to the battery cell, it is conceivable that the bus bar may be deformed as the battery cell expands.

[0005] If a mechanism that suppresses the deformation of these battery cells and allows the bus bar to deform is combined, although the occurrence of bus bar damage can be suppressed, it will lead to an increase in the mass of the bus bar itself, an increase in the volume of the bus bar, and thus an increase in the mass and volume of the battery pack itself. And it may lead to complication of bus bar welding, insufficient welding strength, deviation, and sometimes the cover is likely to fall off due to the increase and complication of conductive components, and short circuits are likely to occur. Summary of the Utility Model

[0006] In view of the above situation, the present utility model provides a battery module that can suppress the occurrence of adverse conditions accompanying the expansion of battery cells.

[0007] The battery module according to the present utility model includes a plurality of stacked battery cells and insulating members that alternately fix the plurality of battery cells. The insulating members include a first insulator and a second insulator that is more deformable than the first insulator. Before the expansion amount of the plurality of battery cells reaches a specified amount, the insulating members disposed between the battery cells are pressed in the radial direction and deformed to become thinner in the radial direction. When the expansion amount of the plurality of battery cells reaches the specified amount, the deformation of the insulating members becoming thinner in the radial direction stops, and the deformation of the plurality of battery cells is suppressed and the movement of the plurality of battery cells is suppressed by the elastic force in the extending direction of the insulating members.

[0008] According to the present utility model, a battery module that suppresses the occurrence of adverse conditions accompanying the expansion of battery cells can be provided. Brief Description of the Drawings

[0009] Figure 1A 、 Figure 1B 、 Figure 1C 、 Figure 1D, Figure 1E , Figure 1F , Figure 1G and Figure 1H are diagrams showing the structure of a battery module according to an embodiment.

[0010] Figure 2A , Figure 2B , Figure 2C , Figure 2D and Figure 2E are diagrams showing the configuration of an insulating member according to an embodiment.

[0011] Figure 3A , Figure 3B , Figure 3C , Figure 3D , Figure 3E , Figure 3F and Figure 3G are diagrams showing various configuration examples of battery cells and insulating members according to an embodiment. Detailed Embodiment

[0012] A battery module according to an embodiment will be described below with reference to the accompanying drawings. Figure 1A , Figure 1B , Figure 1C , Figure 1D , Figure 1E , Figure 1F , Figure 1G and Figure 1H are diagrams showing a plurality of battery cells 11 constituting the battery module and insulating members 12 and 13 for fixing the battery cells 11 to each other. In addition, a case where the battery cells 11 are formed to be thinner in the front - rear direction than in the left - right direction and the up - down direction and are stacked with the front - rear direction as the stacking direction will be described. Figure 1A is a diagram showing a plurality of battery cells 11 from the viewpoint of the left - right direction, Figure 1B is a diagram showing a plurality of battery cells from the viewpoint of the up - down direction. In addition, in Figure 1A , Figure 1B , in order to distinguish the insulating member 12 and the insulating member 13, the insulating member 13 is shown thicker, but typically, both are strip - shaped with the same thickness.

[0013] A battery module is a module that aggregates a plurality of battery cells 11 and adjusts the capacity or voltage to an appropriate value by series or parallel connection. In addition, by connecting a plurality of battery modules to each other and housing them in a case, they can be packaged as one system to form a battery pack.

[0014] For ease of explanation, Figure 1A and Figure 1BAmong them, a plurality of battery cells 11 will be described in sequence as battery cells 11a, 11b, 11c, and 11d starting from the left (front) side in the figure. The number of battery cells provided in one battery module is not limited to these.

[0015] As Figure 1A and Figure 1B shown, a plurality of battery cells 11 are alternately fixed by cord-shaped insulating members 12 and 13. More specifically, battery cell 11a and battery cell 11c are fixed by insulating member 12, and battery cell 11b and battery cell 11d are fixed by insulating member 13.

[0016] Next, the insulating members 12 and 13 will be described. In addition, since the structures of insulating member 12 and insulating member 13 can be substantially the same, only insulating member 12 will be described.

[0017] Insulating member 12 is an elastic cord-shaped or ring-shaped member. Insulating member 12 is composed of deformable insulators 12a and 12b. Insulator 12a is a fibrous raw material with strong elasticity or low elasticity. Insulator 12b is a raw material that is softer and easier to deform than insulator 12a. In addition, insulator 12a is set as the first insulator, and insulator 12b is set as the second insulator.

[0018] As an example, insulator 12a can be made of twisted fibers such as cellulose, or rubber with high hardness. As insulator 12b, rubber that is soft and easy to deform can be used. For insulator 12a and insulator 12b, the same kind of rubber with different hardnesses can also be used.

[0019] Here, Figure 2A is a diagram showing an example of a cross-section perpendicular to the extending direction of insulating member 12, Figure 2B is a diagram showing an example of a cross-section parallel to the extending direction of insulating member 12. As Figure 2A shown, in insulating member 12, a plurality of insulators 12a with small diameters are arranged in such a way that they are buried inside the insulator 12b with a large diameter. In other words, insulator 12b covers the surface of insulator 12a and encloses a plurality of insulators 12a in an integrated manner.

[0020] And Figure 2A similarly, Figure 2C is a cross-section perpendicular to the extending direction of insulating member 12, which is an example of another configuration of insulator 12a and insulator 12b. As Figure 2C shown, insulator 12a can be configured to protrude from the surface of insulator 12b.

[0021] Figure 2D and Figure 2EAs an example of other configurations of the insulators 12a and 12b, Figure 2D is a view point in the extending direction of the insulator 12a, Figure 2E is a view shown from a direction perpendicular to the extending direction of the insulator 12a. As Figure 2D and Figure 2E shown, the insulating member 12 can be formed by spirally winding a thin insulator 12b around a bundle of the insulator 12a.

[0022] Here, as Figure 2A shown, when a radial external force is applied to the insulating member 12, the thickness of the outer diameter or the cross-sectional shape is likely to be deformed. On the other hand, as Figure 2B shown, since the insulator 12a is not likely to change in the fiber direction, i.e., the extending direction, the insulating member 12 as a whole is not likely to be deformed in the extending direction.

[0023] In addition, the insulating member 12 is in a rope shape or a ring shape and has a sufficient length for winding around the battery cell 11. In addition, the maximum allowable amount of deformation of one side of the battery cell 11 is set, and the thickness of the insulating member 12 is less than this. In addition, the cross-sectional shapes of the insulators 12a and 12b may not be circular, and can be changed to a square shape, an irregular shape, etc., as long as the insulator 12a is not easily deformed and the insulator 12b is easily deformed. In addition, depending on the shapes of the insulators 12a and 12b, the same raw material can also be used.

[0024] When the insulating member 12 is provided to the battery cell 11, the arrangement can be changed according to the shape of the insulating member 12. Specifically, when the insulating member 12 is in a rope shape, as Figure 1A and Figure 1B shown, it is wound one by one or in multiple in an alternating manner.

[0025] Here, Figure 1C and Figure 1D are examples of always winding the insulating members 12 and 13 at a height near the center of the battery cell 11 in the left-right direction view point. In this case, after adjusting the entire battery cell 11 with an initial pressure, the ends are fixed with an end plate or the like. In addition, Figure 1E shows the battery cell 11 and the insulating member 12 from the front-back direction view point. Since the insulating member 12 can be wound around the battery cell 11 for any number of turns more than one turn, an example of a state of winding three turns is shown.

[0026] On the other hand, in Figure 1F , Figure 1CWhen the insulating members 12 and 13 are annular in the state shown, the plurality of insulating members are hooked and fixed in a figure-eight manner in units of one battery cell or two to three battery cells. In this case, it is necessary to adjust the lengths of the insulating members 12 and 13 according to the shape of the battery cell 11. When the lengths do not match, the lengths are adjusted at positions where they do not interfere with the stacking surface of the battery cell 11. In addition, Figure 1G and Figure 1H are diagrams showing the battery cell 11 and the insulating members 12 and 13 from the perspective of the vertical direction for the cases where the insulating members 12 and 13 are cord-like and annular, respectively.

[0027] Here, Figure 3A is a state where the insulating member 12 or the insulating member 13 is provided near the center or alternately arranged, and is a state where an initial pressure is applied. In particular, in Figure 3A is a diagram showing an example of the cross-section of the insulating member 12 sandwiched between the stacking surfaces, i.e., the battery cells 11a and 11b, and shows a slightly deformed state. Figure 3B is a cross-sectional view showing the state where the deterioration of the battery cell 11 progresses and the deformation in the thickness direction of the insulating member 12 arranged between the battery cells 11 becomes larger. As the battery cell 11 expands from the central portion, the insulating member 12 arranged near the central portion between the respective battery cells 11 is squeezed, and the insulating member 12 deforms in a manner of becoming shorter in the radial direction. That is, before the battery cell 11 reaches a specified expansion amount, as the central portion of the battery cell 11 deforms, the insulating member 12 becomes a thin shape, and by allowing the deformation, stress concentration can be alleviated.

[0028] After that, when the expansion of the battery cell 11 reaches the specified expansion amount, the insulating member 12 becomes the thinnest shape. At this time, in the insulating member 12, based on the property of the insulator 12a as a constituent that is not easily deformed in the extending direction, further deformation is prevented, and a strong elastic force is generated. That is, the insulating member 12 acts a force in the contracting direction in the extending direction, and this force acts as a force to prevent the expansion of the battery cell 11, and becomes a force to fix the distance between the battery cells 11 so that it cannot be further changed. Figure 3C and Figure 3D are side views and top views of the battery cell 11 and the insulating member 12 showing the state where the force in the contracting direction acts, indicated by arrows.

[0029] As a result, the battery cells 11 are in a state where a force to approach each other is applied. Therefore, in the exterior packaging of the battery cell 11, a specified expansion is allowed, and expansion beyond the specified amount is prevented, and the distance between the battery cells 11 can be prevented from expanding to more than a certain value. Thereby, stress concentration and breakage of the bus bar connecting the battery cells 11 can be suppressed.

[0030] In addition, the present utility model is not limited to the above-described embodiments and can be appropriately changed without departing from the gist. That is, for the sake of clarity of explanation, the above description has been appropriately omitted and simplified. For those skilled in the art, it is easy to change, add, and transform each element of the embodiment within the scope of the present utility model.

[0031] For example, as Figure 3E shown, it can be configured such that other plate-shaped insulating members 14 are further added between the battery cells 11.

[0032] Here, similar to the insulating members 12 and 13, the plate-shaped insulating member 14 is an insulator, and a resin material that does not deform at normal temperature can be used. Here, the plate-shaped insulating member 14 is plate-shaped with a shape equivalent to the front and rear surfaces of the battery cell 11 and an area equivalent to the area of the front and rear surfaces, and is initially constrained simultaneously with the battery cell 11.

[0033] In this case, the insulating member 12 connects the plate-shaped insulating members 14 in the stacking direction. As an example, it is connected to the entire side surface of the plate-shaped insulating member 14. At this time, as Figure 3F shown, from the upper viewpoint, the insulating member 12 connects the side surfaces of the plate-shaped insulating members 14 in such a manner that the insulating members 14 are alternately connected at the left and right ends. Here, when the insulating member 12 is plate-shaped, an adhesive can be used for the connection method with the insulating member 14, but it is not limited thereto.

[0034] On the other hand, the insulating member 13 is disposed near the center of the battery cell 11 with respect to the plate-shaped insulating member 14. Here, regarding the setting method of the insulating member 13, it is only necessary to be able to adhere to the central portion of the plate-shaped insulating member 14, and the method is not limited. For example, an adhesive can be used.

[0035] When the plate-shaped insulating member 14 clamps the battery cell 11, it is constrained together with the battery cell 11. At this time, the insulating member 13 gradually deforms until the battery cell 11 expands to reach the upper limit of allowable deformation.

[0036] And, as Figure 3G shown, when the battery cell 11 reaches the upper limit of allowable deformation, the expanded battery cell 11 interferes with the plate-shaped insulating member 14 directly or via the insulating member 13. At this time, the distance between the plate-shaped insulating members 14 is maintained within a certain value by the insulating member 12. In addition, Figure 3G the arrow of

[0037] represents an example of the direction of the applied force. Thus, in the battery module, it is possible to prevent deformation of the battery cell 11 beyond the allowable amount and suppress deformation of the bus bar.

Claims

1. A battery module, characterized in that: A plurality of stacked battery cells and an insulating member for alternately fixing the plurality of battery cells are provided. The insulating member includes a first insulator and a second insulator that is more easily deformed than the first insulator. Before the expansion amount of the plurality of battery cells reaches a predetermined amount, the insulating member disposed between the battery cells is pressed in the radial direction and deformed to become thinner in the radial direction. When the expansion amount of the plurality of battery cells reaches a predetermined amount, the insulating member stops deforming in a radial direction and the elastic force of the insulating member in the extending direction suppresses the deformation of the plurality of battery cells, thereby suppressing the movement of the plurality of battery cells.

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