Battery pack

Abstract

The present invention relates to a battery pack in which a stack, in which a plurality of battery cells are stacked, is pressed by both side surfaces of a case from both ends in the stacking direction of the battery cells via a gasket body, and the stack is held between both side surfaces of the case, the gasket body having an opening extending in the thickness direction of the gasket body, a protruding part protruding into the opening part of the gasket body is formed on the side face, abutting against the gasket body, of the shell. As a result, displacement of the gasket body in the surface direction of the side surface of the case can be prevented, and the cell stack can be more stably held.

Description

Technical Field

[0001] The present invention relates to a battery pack that houses a battery stack formed by stacking a plurality of battery cells, and more specifically, to a configuration of a battery pack configured to hold the stacked state of a plurality of battery cells by pressing both ends of the battery stack with the side surfaces of a housing. Background Art

[0002] As configurations of battery packs that house a battery stack formed by stacking a plurality of battery cells, various structures have been proposed. For example, Patent Document 1 describes the following structure: A battery array formed by stacking a plurality of battery cells is arranged in an installation space inside a box-shaped housing, and a set of adjustment shims formed by a plurality of adjustment shims is interposed between the end of the battery array in the stacking direction of the battery cells and the side surface of the housing, and a wedge member is inserted between the end of the battery array on the opposite side and the side surface of the housing to press the battery array and the set of adjustment shims. In addition, Patent Document 2 discloses the following structure: Battery cells are arranged on the surface of a flat chassis having three substantially perpendicular wall surfaces, and a holding plate is arranged via an adjustment plate on the surface of the battery cells opposite to the surface in contact with the chassis, and its edge is connected to the wall surface of the chassis, and the battery cells are fixed in such a way that the holding plate presses the battery cells against the surface of the chassis.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-528973

[0004] Patent Document 2: International Publication No. 2016 / 189745

[0005] As one of the structures of a battery pack that houses a battery stack in a frame (housing), a structure has been proposed in which the battery stack is held between the two side surfaces of the frame while being pressed from both ends in the stacking direction of a plurality of battery cells. In this case, more specifically, as Figure 4 shown, first, a plurality of battery cells 2 are stacked in the thickness direction with a resin frame 2a interposed therebetween, and resin plates 3 and 4 are arranged at both ends thereof. In this state, the plurality of battery cells 2 are pressed and clamped by the plates 3 and 4 (refer to arrow P), and the battery cells 2 are brought into close contact with each other with the resin frame 2a interposed therebetween to form a battery stack 1a. Then, the battery stack 1a is assembled together with a gasket 6 (which may be formed by stacking a plurality of gaskets) inside the housing 5 (refer to arrows S and T). At this time, the surface of the plate 4 of the battery stack 1a abuts against one side surface 5r of the housing 5, and the plate 3 of the battery stack 1a faces the other side surface 5l of the housing 5 with the gasket 6 interposed therebetween. The side surfaces 5r and 5l of the housing 5 apply a compressive force to the battery stack 1a and the gasket 6 in the stacking direction of the battery cells 2, thereby stably holding the battery stack 1a inside the housing 5. Then, a bus bar module 7 for electrically connecting a plurality of battery cells 2 and a cushioning material 8 for pressing and protecting the battery stack 1a from above are arranged.

[0006] As described above, in the structure in which the battery stack 1a and the gasket 6 are pressed and held from both side surfaces of the housing 5, when the gasket 6 is adhered with double-sided tape or the like so as not to shift in the surface direction of the side surface of the housing 5 (in the case where a plurality of gaskets are stacked, the gaskets are also adhered with double-sided tape), if the gasket 6 is merely clamped between the side surface 51 of the housing 5 and the plate 3, then as Figure 5 schematically depicted, when the battery stack 1a is tilted and a component in the surface direction is generated in the pressing force F acting on the battery stack 1a, sliding or the like occurs at the interface of the double-sided tape adhering the gasket 6. Therefore, as indicated by the arrow z, the gasket 6 may be displaced in the surface direction from the housing 5, and a phenomenon in which the gasket 6 and the battery stack 1a float from the housing 5 may occur. SUMMARY OF THE INVENTION

[0007] In view of the above circumstances, the main technical problem to be solved by the present invention is how to prevent the gasket from shifting in the surface direction of the side surface of the housing in a battery pack having a structure in which a battery stack formed by stacking a plurality of battery cells is pressed from both ends in the stacking direction of the battery cells by both side surfaces of the housing and the battery stack is held in the housing via the gasket.

[0008] To solve the above technical problem, the present invention adopts the following technical solution.

[0009] A first technical solution is a battery pack, wherein a battery stack formed by stacking a plurality of the battery cells is pressed from both ends in the stacking direction of the battery cells by both side surfaces of the housing via a gasket body, and the battery stack is held between the both side surfaces of the housing. The gasket body has an opening extending in the thickness direction thereof, and a convex portion protruding into the opening of the gasket body is formed on the side surface of the housing that abuts against the gasket body.

[0010] In the above structure, the "battery pack" refers to a substance that houses a battery inside a housing and is mounted on an electric vehicle or other mechanical device for driving or working. The "battery cell" can be any battery cell used in the art. Typically, it can be as described with respect to Figure 4As described, a plurality of battery cells are stacked with a resin frame, and plates made of resin are installed at both ends of the stacking direction to form a battery stack. The "gasket body" may be a flat plate-shaped component formed of any material (resin, metal) and sandwiched between components for position adjustment in the art. In the present invention, the gasket body may be a single flat plate-shaped component, but may be a material formed by stacking a plurality of gaskets as flat plate-shaped components as described in the embodiment column described later, thereby enabling the thickness of the gasket body to be appropriately changed by adjusting the number of stacked sheets. The "shell" may be a component in the art that is formed of any material (resin, metal) and has a shape in which the side faces stand upright on a flat plate and is used as a frame. The shell may be a die-cast shell (a shell formed by die casting), but is not limited thereto.

[0011] In the above structure, the gasket body sandwiched between the battery stack and the side surface of the shell has an opening extending in the thickness direction thereof, and a convex portion protruding into the opening is formed on the side surface of the shell to limit the displacement of the gasket body along the surface direction of the side surface of the shell. Thus, even if a force component in the surface direction of the side surface of the shell is generated on the gasket body due to the inclination of the battery stack, the displacement of the gasket body in the surface direction of the side surface of the shell can be prevented, and the battery pack can be held more stably.

[0012] The second technical solution is that in the above-mentioned first technical solution, the opening of the gasket body penetrates the gasket body in the thickness direction of the gasket body, and the convex portion on the side of the shell that abuts against the gasket body is inserted into the opening of the gasket body and extends to the concave portion formed on the surface of the battery stack that abuts against the gasket body.

[0013] According to this structure, the displacement of the battery stack in the surface direction of the side surface of the housing is also restricted, and together with the gasket body, the battery stack is also more stably held in the surface direction of the side surface of the housing.

[0014] The third technical solution is that, in the above-mentioned second technical solution, the protruding length of the convex portion on the side of the shell that abuts against the gasket body is greater than the thickness of the gasket body and less than the sum of the thickness of the gasket body and the depth of the concave portion of the battery stack.

[0015] According to this structure, the pressing force from the side of the housing acts reliably on the battery stack, and the battery stack can be held more stably.

[0016] The fourth technical solution is that, in the above-mentioned first technical solution, the gasket body is a stack of multiple gaskets, each of the multiple gaskets has an opening, and the openings of the multiple gaskets are aligned to form the opening of the gasket body.

[0017] The fifth technical solution is that in the above-mentioned first technical solution, the shell is a die-cast shell.

[0018] In addition, in the present invention, a recess may not be formed on the battery stack. In this case, the convex portion on the side surface of the housing is formed to have a length equal to or less than the thickness of the gasket body.

[0019] According to the present invention, in a battery pack having a structure in which a battery stack formed by laminating a plurality of battery cells is pressed by both side surfaces of a housing from both ends in the lamination direction of the battery cells and a gasket, and the battery stack is held in the housing, it is possible to prevent the gasket from floating and hold the battery stack in the housing more stably. The battery pack of the present invention can be used in various electric vehicles and other mechanical appliances that operate using the power of a battery.

[0020] Other objects and advantages of the present invention will become apparent from the following description of the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A A schematic cross-sectional view of the battery pack to which this embodiment is applied, as viewed from the side.

[0022] Figure 1B A schematic cross-sectional view of the battery pack to which this embodiment is applied, as viewed from above.

[0023] Figure 2A A front view schematic diagram of the side surface of the housing of the battery pack to which this embodiment is applied and in contact with the gasket.

[0024] Figure 2B A top view schematic diagram of the gasket.

[0025] Figure 3A A schematic cross-sectional view of the state before the housing, the gasket, and the battery stack are connected in one form of this embodiment, as viewed from above.

[0026] Figure 3B It is Figure 3A A schematic cross-sectional view of the state after the housing, the gasket, and the battery stack corresponding thereto are connected, as viewed from above.

[0027] Figure 3C A schematic cross-sectional view of the state after the housing, the gasket, and the battery stack are connected in another form of this embodiment, as viewed from above.

[0028] Figure 4 A diagram for explaining a battery pack having a structure in which a battery stack is held between both side surfaces of a frame while being pressed from both ends in the lamination direction of a plurality of battery cells, and showing the state of arranging a plurality of battery cells in the thickness direction for laminating a plurality of battery cells, the state of the battery stack formed by laminating a plurality of battery cells, the state of the gasket and the housing, and the state of the battery pack and the gasket disposed in the housing.

[0029] Figure 5 This is a schematic cross-sectional view from the side, illustrating a state in which a gasket in the prior art floats from a state in which a housing, a gasket, and a battery pack are connected. Specific implementation method

[0030] Some preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same parts.

[0031] First, the structure of the battery pack is explained.

[0032] Reference Figure 1A 、 Figure 1B , in the battery pack 1 of this embodiment, Figure 4 Similarly, a plurality of battery cells 2 are stacked in the thickness direction with a resin frame 2a therebetween to form a battery stack 1a, and the battery stack 1a is arranged together with a gasket 6 arranged at at least one end in a state pressed by the two side surfaces 5l, 5r of the shell 5, and is held between the two side surfaces 5l, 5r of the shell 5. The battery cell 2 can be any battery cell used in the art, and the resin frame 2a can be a component commonly used as a resin component between the battery cells 2. In addition, plates 3, 4 made of insulating resin materials are usually installed at both ends of the battery stack. The shell 5 can typically be a metal shell cast by die casting technology, and specifically, as shown in the figure, it can be a frame formed by uprightly forming side surfaces around a flat plate-shaped component. As shown in the figure, typically, the gasket 6 can be formed by stacking a plurality of resin or metal flat plate-shaped components, and the number of sheets can be adjusted according to the size of the interval between the gaskets 6 (the gasket 6 can be single, in which case it also belongs to the scope of this embodiment). In addition, when the gasket 6 is formed by stacking a plurality of flat plate-shaped members, they can be bonded together using double-sided tape.

[0033] Next, the structure for limiting the displacement of the gasket in the surface direction of the side surface of the housing is described.

[0034] In the structure of the battery pack 1 described above, in the case of this embodiment, as according to Figure 2A 、 Figure 2B As can also be understood, an opening 6a is formed on the gasket 6 along its thickness direction, and a convex portion 5a is formed on the side 51 of the shell. When the gasket 6 is arranged between the side 51 of the shell and the plate 3 of the battery stack 1a, the convex portion 5a is inserted into the opening 6a of the gasket 6 in a manner aligned with the opening 6a of the gasket 6. As a result, the displacement of the gasket 6 along the surface direction of the side 51 of the shell is restricted. In this way, even if the battery stack 1a is slightly tilted and a component of force along the surface direction of the side 51 of the shell is generated, the position of the gasket is maintained, and the battery stack is maintained in a state of being more stably held in the shell.

[0035] Regarding the configuration in which the opening 6a is formed in the gasket 6 and the convex portion 5a inserted into the opening 6a is formed on the side surface 5l of the housing as described above, in one aspect, it can be formed as Figure 1A , Figure 1B follows: The opening 6a of the gasket 6 penetrates the gasket 6 in the thickness direction. On the other hand, in alignment with the opening 6a, a recess 3a is formed in the plate 3 of the battery stack. The convex portion 5a of the side surface 5l of the housing penetrates the opening 6a of the gasket 6 and extends to the recess 3a of the plate 3 of the battery stack. Thus, the recess 3a of the plate 3 also restricts the displacement of the gasket 6 in the plane direction of the side surface 5l of the housing, and the plate 3 and the gasket 6 are in surface contact and adhere closely, and the gasket 6 can be held more stably on the side surface 5l of the housing. In addition, in this case, as Figure 3A schematically shown, when the gasket 6 is disposed on the side surface 51 of the housing and then the plate 3 is disposed thereon (refer to arrow x), the tip of the convex portion 5a of the side surface 51 of the housing reaches the recess 3a of the plate 3 through the opening 6a of the gasket 6 (refer to arrow y). At this time, preferably, as Figure 3B shown, the convex portion 5a is formed such that its protruding length a is less than the sum of the thickness c of the gasket 6 multiplied by N (N: the number of gaskets) and the depth b of the recess (a < c×N + b).

[0036] According to this configuration, the pressing force from the side surface 5l of the housing toward the plate 3 is transmitted through the gasket 6, and the gasket 6 is also reliably subjected to the pressing force from both sides thereof. In this way, the battery stack and the gasket 6 can be held more stably without displacement relative to the side surface 5l of the housing.

[0037] In addition, in another aspect, when no recess is formed in the plate 3, the convex portion 5a of the side surface 5l of the housing is formed such that its protruding length a is equal to or less than the thickness c of the gasket 6 multiplied by N. In this case, the displacement of the gasket 6 in the plane direction of the side surface 5l of the housing is also prevented, and the phenomenon that the gasket 6 floats up from between the side surface 5l of the housing and the plate 3 can be prevented.

[0038] Thus, in the configuration of the above-described embodiment, in the case of a battery pack in which a battery stack formed by laminating a plurality of battery cells is pressed by both side surfaces of a housing from both ends in the lamination direction of the battery cells and a gasket, and the battery stack is held in the housing, floating of the gasket is prevented, and the battery stack can be held in the housing more stably. Regarding this point, in the case of the battery pack targeted by the present embodiment, in order to ensure the performance such as holding of the wound body of the battery cell and prevention of an increase in resistance, a certain load needs to be applied to the battery cell, and this load is determined by the spring constant of the housing and the distance between the side surfaces. Since there is a certain degree of deviation in the size of the battery stack sandwiched between the side surfaces of the housing, in order to compensate for this, a gasket is sandwiched between the housing side surface and the battery stack to adjust the load applied to the battery cell. According to the present embodiment, it is advantageous in terms of not impairing the function of the gasket and preventing the gasket from shifting. The battery pack of the present embodiment is advantageously used for a drive device of an electric vehicle or the drive or operation of other mechanical appliances.

[0039] The above is the description of the embodiment of the present invention. However, many modifications and changes can be easily made by those skilled in the art. Obviously, the present invention is not limited to the above-described exemplary embodiments and can be applied to various devices without departing from the concept of the present invention.

Claims

1. A battery pack, characterized in that: The battery stack formed by stacking a plurality of battery cells is pressed by the two side surfaces of the shell from both ends of the stacking direction of the battery cells via the gasket body, and the battery stack is held between the two side surfaces of the shell. The gasket body has an opening extending in a thickness direction thereof, and a convex portion protruding into the opening of the gasket body is formed on a side surface of the housing that contacts the gasket body.

2. The battery pack according to claim 1, characterized in that: The opening of the gasket body penetrates the gasket body in the thickness direction of the gasket body. The convex portion on the side surface of the housing that contacts the gasket body is inserted through the opening of the gasket body and extends to a concave portion formed on the surface of the battery stack that contacts the gasket body.

3. The battery pack according to claim 2, characterized in that: The protruding length of the convex portion on the side surface of the housing abutting against the gasket body is greater than the thickness of the gasket body and less than the sum of the thickness of the gasket body and the depth of the concave portion of the battery stack.

4. The battery pack according to claim 1, characterized in that: The gasket body is a stacked body of a plurality of gaskets, each of the plurality of gaskets has an opening, and the openings of the plurality of gaskets are aligned to form the opening of the gasket body.

5. The battery pack according to claim 1, characterized in that: The housing is a die-cast housing.

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