Battery pack

Abstract

To provide a battery pack capable of applying a restraining force to a battery cell even when a battery cell expands.SOLUTION: A battery pack 1 includes a battery stack 2 formed by stacking a plurality of battery cells 22, a die-cast case 3, a UPR cover 4, a cell damper 5 provided between the upper surface of the battery stack 2 and the lower surface of the UPR cover 4 and connecting the battery stack 2 and the UPR cover 4, and fastening portions 6 provided on the die-cast case 3 and the UPR cover 4 and fastening the die-cast case 3 and the UPR cover 4 in an orthogonal direction X that is perpendicular to the stacking direction Y of the battery cells 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack. [Background technology]

[0002] Patent Document 1 describes a technology for a battery pack that includes a lower box that houses a battery module and an upper box that covers the lower box and forms an enclosed space to house the battery module. In this technology, the lower box and the upper box are provided with fastening parts around their entire peripheries to fasten (fix) the lower box and the upper box together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-539970 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned Patent Document 1, fastening parts are provided in the stacking direction in which multiple battery cells (battery modules) are stacked, which fixes movement in the stacking direction, resulting in a problem in that the upper box cannot expand in the stacking direction when the battery cells expand, and the upper box cannot press against the top surfaces of the battery cells.

[0005] The present disclosure has been made in consideration of the above, and aims to provide a battery pack that can apply a restraining force to a battery cell even when the battery cell expands. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the objectives, the battery pack of the present disclosure comprises a battery stack formed by stacking a plurality of battery cells, a case having an opening and accommodating the battery stack, a cover covering the opening of the case, a cell damper provided between the upper surface of the battery stack and the lower surface of the cover and connecting the battery stack and the cover, and fastening portions provided on the case and the cover and fastening the case and the cover in a direction perpendicular to the stacking direction of the battery cells. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a restraining force to the battery cell even when the battery cell expands. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a battery pack according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the state of the battery pack when the battery cell according to the embodiment expands. DETAILED DESCRIPTION OF THE INVENTION

[0009] Battery packs according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the drawings referred to in the following description merely show a schematic representation of the shape, size, and positional relationship to the extent that the contents of the present disclosure can be understood. In other words, the present disclosure is not limited to the shape, size, and positional relationship exemplified in each drawing.

[0010] [Battery pack configuration] Fig. 1 is a cross-sectional view showing a schematic configuration of a battery pack according to one embodiment. The battery pack 1 shown in Fig. 1 is mounted on a vehicle such as an FCEV (Fuel Cell Electric Vehicle). The battery pack 1 includes a battery stack 2, a die-cast case 3, a UPR cover 4, a cell damper 5, and a fastening portion 6.

[0011] The battery stack 2 is configured by alternately stacking resin frames 21 and battery cells 22, and compressing the plurality of resin frames 21 and the plurality of battery cells 22 via a pair of end plates 23 at both ends of the stacking direction. In the following description, the stacking direction in which the resin frames 21 and battery cells 22 are alternately stacked is referred to as the stacking direction Y (front-to-back direction) of the battery pack 1, the direction perpendicular to the stacking direction Y is referred to as the perpendicular direction X (left-to-right direction) of the battery pack 1, and the vertical direction perpendicular to the stacking direction Y is referred to as the vertical direction Z (up-down direction) of the battery pack 1.

[0012] The battery stack 2 configured in this manner is housed in the die-cast case 3 via shims 24. The shims 24 adjust the gap between the battery stack 2 and the die-cast case 3. The shims 24 bias the battery stack 2 in the stacking direction Y so that the resin frame 21 and battery cells 22 are compressed in the stacking direction Y via a pair of end plates 23 of the battery stack 2, keeping the restraint load within a target value. This is to ensure performance by maintaining the wound state of the battery cells 22 and preventing an increase in battery cell resistance, and to ensure battery stack retention by preventing the battery stack 2 from floating up due to external input. For this reason, the restraint load for the length of the battery stack 2 and die-cast case 3 in the stacking direction Y is determined from the spring constant.

[0013] The die-cast case 3 has a rectangular parallelepiped shape with an opening and houses the battery stack 2 inside. The die-cast case 3 is formed using a material that can stretch in the stacking direction Y when the battery cells 22 expand. In one embodiment, the die-cast case 3 functions as a case.

[0014] The UPR cover 4 is shaped to cover the opening of the die-cast case 3. The UPR cover 4 has a U-shaped cross section. The UPR cover 4 has a flange portion 42 that is fastened (fixed) to the die-cast case 3 (described later) with screws or the like, and a pressing portion 41 on the underside that presses against the die-cast case 3. In one embodiment, the UPR cover 4 functions as a cover.

[0015] The cell damper 5 is provided between the upper surface of the battery stack 2 and the lower surface of the UPR cover 4, and connects the battery stack 2 and the UPR cover 4. The cell damper 5 is a rectangular plate-shaped cushioning material that extends in the width direction and the stacking direction Y. The cell damper 5 is preferably made of an elastic material such as rubber or sponge, but may also be a rigid body.

[0016] The fastening portions 6 are provided in the perpendicular direction X, which is perpendicular to the stacking direction Y of the battery cells 22 in the die-casting case 3 and the UPR cover 4. Specifically, the fastening portions 6 are provided only on the short sides (X direction) of the die-casting case 3 and the UPR cover 4. The fastening portions 6 fasten the die-casting case 3 and the UPR cover 4 in the perpendicular direction X, which is perpendicular to the stacking direction Y of the battery cells 22, using screws or the like (not shown). Specifically, the fastening portions 6 are provided only in the perpendicular direction X at both the front and rear ends of the die-casting case 3 via screws (not shown) and flange portions 42 of the UPR cover 4, and fasten (fix) the die-casting case 3 and the UPR cover 4.

[0017] [When the battery cell expands] Next, a description will be given of the state of the battery pack 1 when the battery cell 22 expands. Fig. 2 is a cross-sectional view showing the state of the battery pack 1 when the battery cell 22 expands.

[0018] The battery pack 1 holds the battery cells 22 only through the frictional force between the die-cast case 3 and the battery stack 2 (see FIG. 1 ). Therefore, as shown in FIG. 2 , when the battery pack 1 and the battery cells 22 expand, the die-cast case 3 expands in the stacking direction Y (see arrow A1), reducing the holding force of the die-cast case 3 on the battery stack 2. However, the UPR cover 4 fastened to the die-cast case 3 by the fastening portions 6 also expands in the stacking direction Y (outward), causing the case itself, consisting of the UPR cover 4 and die-cast case 3, to contract in the vertical direction Z (see arrow B1). As a result, it is possible to prevent a decrease in the holding force of the battery cells 22 provided by the die-cast case 3 and UPR cover 4. That is, by contracting the UPR cover 4 downward in the vertical direction Z, it biases the battery cells 22, thereby providing a restraining force for the battery stack 2.

[0019] According to the embodiment described above, the fastening portions 6 are provided in the perpendicular direction X, which is perpendicular to the stacking direction Y of the battery cells 22 in the die-cast case 3 and UPR cover 4, and the UPR cover 4 fastened to the die-cast case 3 by the fastening portions 6 also stretches in the stacking direction Y (outward), causing the case itself made up of the UPR cover 4 and die-cast case 3 to contract in the vertical direction Z (see arrow B1). As a result, it is possible to prevent a decrease in the holding force of the die-cast case 3 and UPR cover 4 on the battery cells 22.

[0020] Further advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0021] Although some of the embodiments of the present application have been described in detail above with reference to the drawings, these are merely examples, and the present invention can be implemented in other forms that have undergone various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in the disclosure of the present invention. [Explanation of symbols]

[0022] 1 battery pack 2 Battery stack 3 Die-cast case 4 UPR Cover 5 Cell Damper 6 Fastening part 21 Resin frame 22 battery cells 23 End plate 24 Sim 41 Pressing section 42 Flange

Claims

1. a battery stack formed by stacking a plurality of battery cells; a case having an opening and accommodating the battery stack; a cover for covering the opening of the case; a cell damper provided between an upper surface of the battery stack and a lower surface of the cover, the cell damper connecting the battery stack and the cover; fastening portions provided on the case and the cover for fastening the case and the cover together in a direction perpendicular to the stacking direction of the battery cells; Equipped with Battery pack.

2. 2. The battery pack according to claim 1, The case and the cover are It has a rectangular parallelepiped shape, The fastening portion is provided only on the short sides of the case and the cover, Battery pack.

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