Battery module

Abstract

To provide a battery module that reduces the risk of occurrence of failure caused by expansion of a battery cell.SOLUTION: A battery module includes: a plurality of battery cells 11 stacked one another; and insulation members 12, 13 that alternately fix the plurality of battery cells 11. The insulation members 12, 13 each include a first insulator, and a second insulator more deformable in comparison with the first insulator. The insulation members 12, 13 arranged between the battery cells 11 are pressed along a radial direction to be deformed to be thin in the radial direction until the expansion amount of the plurality of battery cells 11 reaches a prescribed amount. After the expansion amount of the plurality of battery cells 11 reaches the prescribed amount, the insulation members 12, 13 stop the radial thinning deformation, and suppress deformation of the plurality of battery cells 11 by elasticity in a stretching direction to suppress movement of the plurality of battery cells 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure 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 storing this battery module has been used in vehicles and the like. Patent Document 1 describes a structure in which an elastic body is provided at the center of a battery cell to relieve the concentration of pressure due to the expansion of the center of the battery cell.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a further related technique, it is known to provide a mechanism that gives variability to the length of a bus bar. Here, when the bus bar is arranged in a state fixed to the battery cell, it is conceivable that the bus bar may deform as the battery cell expands.

[0005] Combining the suppression of deformation of these battery cells with a mechanism for allowing deformation of the bus bar can suppress the occurrence of damage to the bus bar, but it is conceivable that the mass of the bus bar itself increases, the volume of the bus bar increases, and the mass and volume of the battery pack itself increase. Furthermore, there is a possibility of complication of bus bar welding, insufficient welding strength, and occurrence of variations, and an increase in conductive components and complication may make the cover easier to come off and short circuits more likely to occur.

[0006] The present disclosure provides a battery module that suppresses the occurrence of problems associated with the expansion of battery cells.

Means for Solving the Problem

[0007] The battery module according to the present disclosure includes a plurality of stacked battery cells and an insulating member that alternately fixes the plurality of battery cells. The insulating member includes a first insulator and a second insulator that is more easily deformed than the first insulator. Until the expansion amount of the plurality of battery cells reaches a predetermined amount, the insulating member disposed between the battery cells is deformed by being pressed in the radial direction and becoming thinner in the radial direction. When the expansion amount of the plurality of battery cells reaches a predetermined amount, the insulating member stops deforming to become thinner in the radial direction, and suppresses the deformation of the plurality of battery cells and suppresses the movement of the plurality of battery cells by the elastic force in the stretching direction. Thereby, while allowing a certain amount of expansion of the battery cells, it is possible to suppress a change in the distance between the cells.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a battery module that suppresses the occurrence of problems associated with the expansion of battery cells.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0010] Embodiment 1 Hereinafter, the battery module 1 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing a plurality of battery cells 11 constituting the battery module 1 and insulating members 12 and 13 for fixing the battery cells 11 to each other. Note that the battery cells 11 are formed thinner in the front-rear direction than in the left-right direction and the up-down direction, and will be described as being stacked with the front-rear direction as the stacking direction. FIG. 1(a) is a diagram showing a plurality of battery cells 11 from the viewpoint of the left-right direction, and FIG. 1(b) is a diagram showing a plurality of battery cells from the viewpoint of the up-down direction. In FIGS. 1(a) and 1(b), the insulating member 13 is thickly displayed for distinguishing the insulating member 12 and the insulating member 13, but typically it is a string-like shape with the same thickness.

[0011] The battery module 1 is configured by bundling a plurality of battery cells 11 and adjusting the capacity and voltage to appropriate values by series / parallel connection. Note that by connecting a plurality of battery modules 1 to each other and housing them in a case to form a single system package, a battery pack can be formed.

[0012] Hereinafter, for ease of explanation, the plurality of battery cells 11 shown in FIGS. 1(a) and 1(b) will be described as battery cells 11a, 11b, 11c, and 11d from the left (front) side in the figure. The number of battery cells provided in one battery module 1 is not limited to these.

[0013] As shown in FIGS. 1(a) and 1(b), the plurality of battery cells 11 are alternately fixed by insulating members 12 and 13 in the form of strings. More specifically, the battery cell 11a and the battery cell 11c are fixed by the insulating member 12, and the battery cell 11b and the battery cell 11d are fixed by the insulating member 13.

[0014] Next, the insulating members 12 and 13 will be described. Since the configurations of the insulating member 12 and the insulating member 13 can be made substantially the same, only the insulating member 12 will be described.

[0015] The insulating member 12 is a string-like or ring-like member having elasticity. The insulating member 12 is composed of variable insulators 12a and 12b. The insulator 12a is a fibrous material having strong elasticity or little elasticity. The insulator 12b is a material that is softer and more deformable than the insulator 12a. Here, the insulator 12a is the first insulator, and the insulator 12b is the second insulator.

[0016] As an example, for the insulator 12a, it is possible to use a twist of fibers such as cellulose or a rubber with high hardness. For the insulator 12b, it is possible to use a rubber that is soft and easily deformable. The same type of rubber with different hardnesses may be used for the insulator 12a and the insulator 12b.

[0017] Here, Fig. 2(a) is a diagram showing an example of a cross-section perpendicular to the stretching direction of the insulating member 12, and Fig. 2(b) is a diagram showing an example of a cross-section parallel to the stretching direction of the insulating member 12. As shown in Fig. 2(a), in the insulating member 12, a plurality of insulators 12a with a smaller diameter are arranged so as to be embedded inside the insulator 12b with a larger diameter. In other words, the surface of the insulator 12a is covered by the insulator 12b, and the plurality of insulators 12a are enclosed so as to be integrated.

[0018] Fig. 2(c) is a cross-section in the direction in which the insulating member 12 extends, similar to Fig. 2(a), and is an example of a different arrangement of the insulator 12a and the insulator 12b. As shown in Fig. 2(c), the insulator 12a can be configured to be exposed from the surface of the insulator 12b.

[0019] Figs. 2(d) and 2(e) are an example of a different arrangement of the insulator 12a and the insulator 12b. Fig. 2(d) is a fulcrum from the stretching direction of the insulator 12a, and Fig. 2(e) is a diagram shown from a viewpoint perpendicular to the stretching direction of the insulator 12a. As shown in Figs. 2(d) and 2(e), the insulating member 12 can be configured by spirally winding a thin insulator 12b around a bundle of the insulators 12a.

[0020] As shown in FIG. 2(a) here, when an external force in the radial direction is applied to the insulating member 12, the outer diameter thickness and cross-sectional shape are easily deformed. On the other hand, as shown in FIG. 2(b), since the insulating member 12 is difficult to change in the stretching direction in which the insulator 12a is in the fiber direction, it is difficult to deform in the stretching direction as a whole.

[0021] Note that the insulating member 12 is in a string shape or an annular shape and has a sufficient length to be wound around the battery cell 11. Also, the thickness of the insulating member 12 is maximized to one side of the deformation allowance of the battery cell 11 and is less than that. Further, the cross-sectional shapes of the insulator 12a and the insulator 12b do not have to be circular, and can be changed to a square shape, an irregular shape, etc. as long as the insulator 12a is difficult to deform and the insulator 12b is easily deformed. Also, depending on the shapes of the insulator 12a and the insulator 12b, the same material may be used.

[0022] When the insulating member 12 is provided with respect to the battery cell 11, the arrangement can be changed according to the shape. Specifically, when the insulating member 12 is in a string shape, as shown in FIGS. 1(a) and 1(b), it is wound around each or a plurality of the battery cells 11 alternately.

[0023] Here, FIGS. 1(c) and 1(d) are examples of viewpoints from the left-right direction in which the insulating members 12 and 13 are wound at a height that always passes near the center of the battery cell 11. In this case, after adjusting the entire battery cell 11 with the initial pressure, the ends are fixed with an end plate or the like. Also, FIG. 1(e) shows the battery cell 11 and the insulating member 12 from the front-rear direction, and since the insulating member 12 may be wound around the battery cell 11 any number of times more than once, an example of a state where it is wound three times is shown.

[0024] On the other hand, when the insulating members 12 and 13 are annular in the states shown in FIGS. 1(f) and 1(c), the plurality of insulating members are hooked and fixed one cell at a time or in a figure-eight shape by two to three 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. If the lengths do not match, the lengths are adjusted at positions that do not interfere with the stacking surface of the battery cell 11. FIGS. 1(g) and 1(h) are diagrams showing the battery cell 11 and the insulating members 12 and 13 from a vertical perspective when the insulating members 12 and 13 are in a string shape and an annular shape, respectively.

[0025] Here, FIG. 3(a) shows a state in which the insulating member 12 or the insulating member 13 is installed near the center or alternately, and an initial pressure is applied. In particular, FIG. 3(a) is a diagram showing an example of the cross section of the insulating member 12 sandwiched between the battery cells 11a and 11b which are the stacking surfaces, and shows a slightly deformed state. FIG. 3(b) is a cross-sectional view showing a state in which 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 large. As the battery cell 11 expands from the central portion, the insulating member 12 arranged near the center between the respective battery cells 11 is pushed in, and the insulating member 12 is deformed so as to become shorter in the radial direction. That is, until the battery cell 11 reaches a predetermined amount of expansion, the insulating member 12 becomes thin as the central portion of the battery cell 11 deforms, and by allowing the deformation, the concentration of pressure can be alleviated.

[0026] After that, when the expansion of the battery cell 11 reaches a predetermined amount of expansion, the insulating member 12 becomes the thinnest shape. At this time, in the insulating member 12, due to the property of being difficult to deform in the stretching direction by the insulator 12a which is a constituent, further deformation is prevented and a strong elastic force is generated. That is, in the insulating member 12, a force in the contracting direction acts in the stretching direction, and this force acts as a force to stop the expansion of the battery cell 11 and also serves as a force to fix the distance between the battery cells 11 so that it cannot vary any further. FIGS. 3(c) and 3(d) are side views and top views of the battery cell 11 and the insulating member 12 showing the state in which the force in the contracting direction acts, indicated by arrows.

[0027] As a result, a force that causes the battery cells 11 to approach each other is applied. Therefore, in the exterior of the battery cell 11, a predetermined expansion is allowed, and an expansion of a predetermined amount or more is prevented, so that the distance between the battery cells 11 can be prevented from spreading by a certain amount or more. Thereby, stress concentration on the bus bar to which the battery cells 11 are connected and breakage can be suppressed.

[0028] Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the gist. That is, the above description has been appropriately omitted and simplified for clarity of explanation, and those skilled in the art can easily change, add, and convert each element of the embodiment within the scope of the present invention.

[0029] For example, as shown in FIG. 3(e), a configuration can be adopted in which another plate-shaped insulating member 14 is further added between the battery cells 11.

[0030] Here, the plate-shaped insulating member 14 is an insulator like the insulating members 12 and 13, and a resin material that does not deform at normal temperature can be used. Here, the plate-shaped insulating member 14 is plate-shaped having a shape equivalent to the front-rear direction surface of the battery cell 11 and an area equivalent to the surface forming the front-rear direction, and is initially restrained simultaneously with the battery cell 11.

[0031] In this case, the insulating member 12 connects the plate-shaped insulating members 14 in the stacking direction. As an example, it connects to the entire side surface of the plate-shaped insulating member 14. At this time, as shown in FIG. 3(f), from a viewpoint from above, the insulating member 12 connects the side surfaces of the plate-shaped insulating members 14 so that the insulating members 14 are alternately connected at the left and right ends. When the insulating member 12 is plate-shaped, an adhesive can be used as a method of connecting to the insulating member 14, but it is not limited thereto.

[0032] On the one hand, the insulating member 13 is installed near the center of the battery cell 11 with respect to the plate-shaped insulating member 14. Here, the installation method of the insulating member 13 is not limited as long as it can be adhered to the center of the plate-shaped insulating member 14. For example, an adhesive can be used.

[0033] When this plate-shaped insulating member 14 sandwiches the battery cell 11, it is constrained together with the battery cell 11. At this time, the insulating member 13 deforms until the battery cell 11 expands to the upper limit of deformation tolerance.

[0034] Then, as shown in Fig. 3(g), when the battery cell 11 reaches the upper limit of deformation tolerance, the expanded battery cell 11 interferes with the plate-shaped insulating member 14 directly or through the insulating member 13. At this time, the distance between the plate-shaped insulating members 14 is maintained within a certain distance by the insulating member 12. The arrow in Fig. 3(g) shows an example of the direction of the applied force.

[0035] Thereby, in the battery module 1, deformation of the battery cell 11 beyond the allowable range can be prevented, and deformation of the bus bar can be suppressed.

Explanation of Reference Numerals

[0036] 1 Battery module 11 Battery cell 12 Insulating member 12a Insulator 12b Insulator 13 Insulating member 14 Plate-shaped insulating member

Claims

【Claim 1】 A plurality of stacked battery cells; An insulating member that alternately fixes the plurality of battery cells to each other; and The insulating member includes a first insulator and a second insulator that is more easily deformed than the first insulator; Until the amount of expansion of the plurality of battery cells reaches a predetermined amount, the insulating member disposed between the battery cells is deformed to be pressed in the radial direction and become thinner in the radial direction; When the amount of expansion of the plurality of battery cells reaches a predetermined amount, the insulating member stops deforming to become thinner in the radial direction, and suppresses the deformation of the plurality of battery cells and suppresses the movement of the plurality of battery cells by the elastic force in the stretching direction; A battery module.

Images