JP2024055518A - Battery housing structure - Google Patents

Abstract

To provide a battery housing structure capable of efficiently utilizing a battery mounting space while securing the whole battery rigidity by a skeleton.SOLUTION: A lower bracket 22 in a battery fastening bracket 2 bonded with a battery module 1, and a reinforcement member 4 arranged outside a lower case 32 configure a skeleton configuration part 5 having a substantially rectangular closed cross section structure. An inclined part 32b of the lower case 32 in a battery case 3 is arranged in a direction along a diagonal line to the substantially rectangular closed cross section structure inside the skeleton configuration part 5. Thereby, a battery mounting space can be efficiently utilized while securing the whole battery rigidity by skeleton configuration part 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a battery housing structure (a housing structure consisting of a battery fastening bracket and a battery case).

Conventionally, electric vehicles, plug-in hybrid vehicles, and the like are equipped with batteries (also called traction batteries) that store electricity to supply power to the motor that serves as the driving force source for the vehicle. Generally, this type of battery is often placed under the floor of the vehicle. In order to extend the vehicle's driving range by using electric power, a battery mounting structure that efficiently uses the battery mounting space under the vehicle floor is required.

Generally, a battery (also called a battery pack) consists of a battery module housed inside a battery case. Battery cases are often formed by drawing sheet metal. As a result, the battery case does not have a skeleton (a skeleton to ensure the rigidity of the entire battery). For this reason, reinforcing members are added as separate components from the battery case, and the skeleton is formed using these reinforcing members.

Figure 3 is a cross-sectional view showing a part of a conventional battery housing structure (a part toward one side in the vehicle width direction) (hatching that indicates a cross section is omitted in this Figure 3). In this Figure 3, the arrow OUT indicates the outside in the vehicle width direction, and the arrow UP indicates the upward direction.

As shown in FIG. 3, a battery fastening bracket b is joined to the side of a battery module a that houses multiple battery cells (not shown). This battery fastening bracket b is made up of an upper bracket b1 and a lower bracket b2, and the flange portions b3 and b4 of these brackets b1 and b2 are overlapped and fastened together. The battery case c that houses the battery module a is made up of an upper case c1 and a lower case c2, and the flange portion b4 of the lower bracket b2 is joined to the inner surface of the lower case c2, so that the battery module a is supported inside the battery case c via the battery fastening bracket b.

The reinforcing member d is joined to the lower case c2, and the reinforcing member d and the lower case c2 form a substantially rectangular closed cross-sectional structure, which forms a skeleton (a skeleton for ensuring the rigidity of the entire battery). In other words, the shaded area in FIG. 3 functions as the skeleton.

JP 2016-141316 A

However, in conventional battery housing structures, the framework is formed by reinforcing member d that protrudes outward in the vehicle width direction from the side of lower case c2, so it cannot be said that the space under the vehicle floor where the battery is mounted is used efficiently. In other words, since reinforcing member d is joined to lower case c2 and a closed cross-sectional structure is formed by reinforcing member d and lower case c2, in order to increase the cross-sectional area of the closed cross-sectional structure to ensure sufficient rigidity, the amount of protrusion to the side from lower case c2 is large. As a result, there is a limit to how much space can be saved in order to mount the battery (battery pack).

The present invention was made in consideration of these points, and its purpose is to provide a battery housing structure that can efficiently use the battery mounting space while ensuring the rigidity of the entire battery through the skeleton.

The solution of the present invention for achieving the above object is based on a battery housing structure including a battery fastening bracket connected to a battery module, a battery case to which the battery fastening bracket is connected and which surrounds the outer periphery of the battery module, and a reinforcing member connected to the outer surface of the battery case. This battery housing structure is characterized in that a skeleton component having a substantially rectangular closed cross-sectional structure is formed by the battery fastening bracket and the reinforcing member, and the components of the battery case are arranged inside the skeleton component in a direction along a diagonal line to the substantially rectangular closed cross-sectional structure.

With this feature, a battery fastening bracket arranged inside the battery case is used to construct a skeletal component of a closed cross-sectional structure using this battery fastening bracket and a reinforcing member, making it possible to construct a closed cross-sectional structure (skeletal component) with a sufficiently large cross-sectional area without the reinforcing member protruding significantly outward. In addition, because the components of the battery case are arranged inside this skeletal component in a direction along the diagonal of the approximately rectangular closed cross-sectional structure, it is possible to obtain a sufficiently high rigidity of the skeletal component.

In the present invention, a skeletal component with a substantially rectangular closed cross-sectional structure is formed by the battery fastening bracket and reinforcing member, and the components of the battery case are arranged inside the skeletal component in a direction along a diagonal line of the substantially rectangular closed cross-sectional structure. In other words, the skeletal component is formed from components that have not previously been used as a skeleton. This makes it possible to save space by efficiently using the battery mounting space while still ensuring the rigidity of the entire battery through the skeletal component.

FIG. 1A is a cross-sectional view showing a part of a battery housing structure according to an embodiment, and FIG. 1B is a cross-sectional view for explaining a framework component. 1 is a cross-sectional view for comparing a battery housing structure according to an embodiment with a battery housing structure according to a conventional technology. FIG. 1 is a cross-sectional view showing a part of a conventional battery housing structure.

The following describes an embodiment of the present invention with reference to the drawings. In this embodiment, the present invention is applied to a battery (driving battery) mounted on an electric vehicle. Vehicles to which the battery housing structure according to the present invention is applied are not limited to electric vehicles, but may also be hybrid vehicles, plug-in hybrid vehicles, etc.

Figure 1(a) is a cross-sectional view showing a part of the battery housing structure according to this embodiment (hatching that indicates a cross section is omitted in this Figure 1(a)). In this Figure 1(a), the arrow OUT indicates the outside in the vehicle width direction, and the arrow UP indicates the upward direction.

As shown in FIG. 1(a), a battery fastening bracket 2 is joined to a battery module 1 that houses multiple battery cells (not shown). The battery fastening bracket 2 includes an upper bracket 21 and a lower bracket 22.

The upper bracket 21 is an L-shaped member with a vertical portion 21a and a flange portion 21b.

The vertical portion 21a is joined to the side surface 11 of the battery module 1.

The flange portion 21b extends outward in the vehicle width direction from the lower end of the vertical portion 21a. In addition, a through hole 21c that penetrates the flange portion 21b in the vertical direction is provided, and a nut N is welded to the upper surface of the flange portion 21b corresponding to the position where the through hole 21c is provided.

The lower bracket 22 has a lower horizontal portion 22a, a vertical portion 22b, and a flange portion 22c.

The lower horizontal portion 22a extends along the vehicle width direction below the battery module 1. The outer end (the outer end in the vehicle width direction) of this lower horizontal portion 22a is located slightly outboard (outside in the vehicle width direction) of the side surface 11 of the battery module 1.

The vertical portion 22b extends upward from the outer end of the lower horizontal portion 22a in the vehicle width direction so as to be parallel to the side surface 11 of the battery module 1.

The flange portion 22c extends outward in the vehicle width direction from the upper end of the vertical portion 22b. The flange portion 22c is provided with a through hole 22d that penetrates in the vertical direction. The through hole 22d is provided at a position that communicates with the through hole 21c formed in the upper bracket 21 when the flange portions 21b, 22c are overlapped. A fastener B is inserted into the through holes 21c, 22d from below, and the fastener B is screwed into a nut N, thereby fastening the upper bracket 21 and the lower bracket 22 together.

The battery fastening bracket 2 may be disposed over the entire side surface 11 of the battery module 1 in the fore-and-aft direction of the vehicle body (the direction perpendicular to the paper surface in FIG. 1(a)), or may be disposed within a predetermined range in the fore-and-aft direction of the vehicle body.

The battery module 1 is housed in a battery case 3. The battery case 3 includes an upper case 31 and a lower case 32. The upper case 31 and the lower case 32 are formed by drawing sheet metal.

The upper case 31 has an upper horizontal portion 31a, a vertical portion 31b, and a flange portion 31c. Although not shown, the upper case 31 also has a front wall portion that covers the front side of the battery module 1 and a rear wall portion that covers the rear side of the battery module 1.

The upper horizontal portion 31a extends along the vehicle width direction so as to cover the upper side of the battery module 1.

The vertical portion 31b extends downward from the outer end of the upper horizontal portion 31a in the vehicle width direction.

The flange portion 31c extends outward in the vehicle width direction from the lower end of the vertical portion 31b.

The lower case 32 has a lower horizontal portion 32a, an inclined portion 32b, and a flange portion 32c. Although not shown, the lower case 32 also has a front wall portion that covers the front side of the battery module 1 and a rear wall portion that covers the rear side of the battery module 1.

The lower horizontal portion 32a extends along the vehicle width direction so as to cover the underside of the battery module 1. The lower horizontal portion 32a is overlapped on the underside of the lower horizontal portion 22a of the lower bracket 22 and joined to the lower horizontal portion 22a.

The inclined portion 32b is inclined outward in the vehicle width direction as it moves upward from the outer end of the lower horizontal portion 32a in the vehicle width direction. For example, it is inclined at an inclination angle of 60° with respect to the horizontal direction. This value is not limited to this value.

The flange portion 32c extends outward in the vehicle width direction from the upper end of the inclined portion 32b. This flange portion 32c is superimposed on the lower surface of the flange portion 22c of the lower bracket 22 and joined to the flange portion 22c. Furthermore, this flange portion 32c is superimposed on the lower surface of the flange portion 31c of the upper case 31 and is also joined to the flange portion 31c.

A reinforcing member 4 is disposed on the outside of the lower case 32. This reinforcing member 4 has a lower horizontal portion 4a, a vertical portion 4b, and a flange portion 4c.

The lower horizontal portion 4a is overlapped on the underside of the lower horizontal portion 32a of the lower case 32 and joined to the lower horizontal portion 32a. In other words, in this portion, the lower horizontal portion 22a of the lower bracket 22, the lower horizontal portion 32a of the lower case 32, and the lower horizontal portion 4a of the reinforcing member 4 are overlapped on one another and joined together.

The vertical portion 4b extends upward from the outer end of the lower horizontal portion 4a in the vehicle width direction so as to be approximately parallel to the side surface 11 of the battery module 1 and the vertical portion 22b of the lower bracket 22.

The flange portion 4c extends outward in the vehicle width direction from the upper end of the vertical portion 4b. The flange portion 4c of the reinforcing member 4 is overlapped on the underside of the flange portion 32c of the lower case 32 and joined to the flange portion 32c. In other words, in this portion, the flange portion 21b of the upper bracket 21, the flange portion 32c of the lower case 32, and the flange portion 4c of the reinforcing member 4 are overlapped on one another and joined together.

In this way, the battery housing structure is formed by the battery fastening bracket 2, the battery case 3, and the reinforcing member 4, which are joined together, and the battery fastening bracket 2 and the reinforcing member 4 form a skeleton component 5 with a substantially rectangular closed cross-sectional structure.

In Fig. 1(b), the skeletal component 5 is shaded in the same cross section as Fig. 1(a). In other words, the vertical portion 22b and flange portion 22c of the lower bracket 22 in the battery fastening bracket 2 and the lower horizontal portion 4a and vertical portion 4b of the reinforcing member 4 form a substantially rectangular closed cross-sectional structure, and this closed cross-sectional structure forms the skeletal component 5 that functions as a skeleton for ensuring the rigidity of the entire battery (battery pack).

The width (dimension in the vehicle width direction) and height of the framework component 5 are preset so that the battery as a whole has a predetermined rigidity. In other words, the length of the vertical portion 22b and flange portion 22c of the lower bracket 22, and the length of the lower horizontal portion 4a and vertical portion 4b of the reinforcing member 4 are each preset. For example, they are set to ensure a cross-sectional area equivalent to the cross-sectional area of the closed cross-sectional structure formed by the reinforcing member d and the lower case c2 in the conventional technology (shown in FIG. 3).

As described above, by constructing the framework component 5 using the lower bracket 22, a component that has not previously been used as a framework, it is possible to create a closed cross-sectional structure with a sufficiently large cross-sectional area without the reinforcing member 4 protruding significantly outward in the vehicle width direction.

In addition, the inclined portion 32b of the lower case 32 is disposed inside the framework 5 in a direction along a diagonal line of the approximately rectangular closed cross-sectional structure. In other words, the lower horizontal portion 32a of the lower case 32 is sandwiched between the lower horizontal portion 22a of the lower bracket 22 and the lower horizontal portion 4a of the reinforcing member 4 and joined to these members 22a, 4a, and the flange portion 32c is sandwiched between the flange portion 21b of the upper bracket 21 and the flange portion 4c of the reinforcing member 4 and joined to these members 21b, 4c. The inclined portion 32b is disposed between these joint portions. As a result, the lower case 32 functions as a brace for the framework 5, which is made of an approximately rectangular closed cross-sectional structure. Therefore, the rigidity of the framework 5 can be sufficiently high.

Figure 2 is a cross-sectional view for comparing the battery housing structure according to this embodiment with the battery housing structure according to the prior art (shown in Figure 3). In Figure 2, the reinforcing member d in the battery housing structure according to the prior art is shown superimposed in virtual lines on the battery housing structure according to this embodiment (shown in Figure 1(a)).

As is clear from FIG. 2, in the battery housing structure according to this embodiment, the amount of protrusion (the amount of protrusion outward in the vehicle width direction) of the reinforcing member 4 is smaller than in the battery housing structure according to the conventional technology by the dimension T in the figure, and the battery mounting space can be used efficiently while ensuring the rigidity of the entire battery by the framework component 5.

As described above, according to this embodiment, the rigidity of the entire battery is ensured by the framework component 5, while the battery mounting space can be used efficiently.

-Other embodiments-
The present invention is not limited to the above-described embodiment, and all modifications and applications within the scope of the claims and equivalents thereto are possible.

For example, in the above embodiment, of the upper bracket 21 and lower bracket 22 that constitute the battery fastening bracket 2, the upper bracket 21 is configured to be joined to the side surface 11 of the battery module 1. The present invention is not limited to this, and the lower bracket 22 may be configured to be joined to the side surface 11 of the battery module 1, or both the upper bracket 21 and the lower bracket 22 may be configured to be joined to the side surface 11 of the battery module 1.

In addition, in the above embodiment, the flange portion 21b of the upper bracket 21, the flange portion 32c of the lower case 32, and the flange portion 4c of the reinforcing member 4 are overlapped with each other and integrally joined. The present invention is not limited to this, and the flange portion 31c of the upper case 31 may be overlapped on the upper side of these members and integrally joined.

In the above embodiment, the skeleton component 5 is provided in the lower half of the battery case 3. In other words, the skeleton component 5 is formed by the lower bracket 22 of the battery fastening bracket 2 and the reinforcing member 4. The present invention is not limited to this, and the skeleton component may be provided in the upper half of the battery case 3. In this case, the upper bracket 21 of the battery fastening bracket 2 is formed in the same shape as the lower bracket 22, and the skeleton component is formed by the upper bracket 21 and the reinforcing member. In addition, the upper case 31 is provided with an inclined portion, and the inclined portion is disposed inside the skeleton component in a direction along a diagonal line of the approximately rectangular closed cross-sectional structure.

The present invention can be applied to battery housing structures in electric vehicles, etc.

REFERENCE SIGNS LIST 1 battery module 2 battery fastening bracket 22 lower bracket 22b vertical portion 22c flange portion 3 battery case 32 lower case 32b inclined portion (battery case constituent member) 4 reinforcing member 4a lower horizontal portion 4b vertical portion 5 framework constituent portion

Claims (1)

A battery housing structure including a battery fastening bracket connected to a battery module, a battery case to which the battery fastening bracket is connected and which surrounds an outer periphery of the battery module, and a reinforcing member connected to an outer surface of the battery case,
A battery housing structure characterized in that a skeletal component having an approximately rectangular closed cross-sectional structure is formed by the battery fastening bracket and the reinforcing member, and the components of the battery case are arranged inside the skeletal component in a direction along a diagonal line of the approximately rectangular closed cross-sectional structure.

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