Battery pack

Abstract

To increase strength of a case provided with a through-hole.SOLUTION: A battery pack 10 comprises a battery module 100, and a pack case 300 for housing the battery module 100. The pack case 300 has a side wall plate 322 for defining a through-hole 324, and a reinforcement member 350 for at least partially covering the through-hole 324.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a battery pack.

Background Art

[0002] In recent years, various battery packs have been developed. A battery pack includes a battery module and a housing that houses the battery module.

[0003] Patent Document 1 describes a battery compartment. The battery compartment includes an aluminum profile and a fixing frame. The aluminum profile is provided with protrusions. The fixing frame is provided with grooves. The protrusions of the aluminum profile and the grooves of the fixing frame are connected to each other by welding.

[0004] Patent Document 2 describes a dissimilar material welding joint. The dissimilar material welding joint includes an upper plate, a lower plate, and a joining auxiliary member. A part of the joining auxiliary member is inserted into a hole provided in the upper plate. The said part of the joining auxiliary member has a welding metal that joins the lower plate and the joining auxiliary member to each other.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] A housing that houses a battery module may define a through hole for passing members such as a cable. However, the strength of the housing may be reduced by the through hole. Therefore, there may be a demand for improving the strength of the housing provided with the through hole.

[0007] An example of the object of the present invention is to improve the strength of a housing provided with a through hole. Other objects of the present invention will become apparent from the description herein.

Means for Solving the Problems

[0008] One aspect of the present invention is as follows. 1. A battery module, A housing that houses the battery module, and The housing has a first member that defines a through hole and a second member that at least partially covers the through hole, a battery pack. 2. The battery pack according to 1., wherein the first member is an extruded product. 3. The battery pack according to 2., wherein the second member is a cast product. 4. The battery pack according to any one of 1. to 3., wherein the first member and the second member are at least partially welded to each other. 5. The battery pack according to any one of 1. to 4., wherein the first member and the second member are at least partially sealed to each other. 6. The battery pack according to any one of 1. to 5., wherein a portion located at at least one of both ends of the through hole of the first member and the second member are joined to each other. 7. The battery pack according to any one of 1. to 6., further comprising a cable passing through the through hole.

Effects of the Invention

[0009] According to the above aspect of the present invention, the strength of the housing provided with the through hole can be improved.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0012] FIG. 1 is a schematic plan view of a battery pack 10 according to an embodiment. FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. For the sake of explanation, in FIG. 1, the upper plate 330 shown in FIG. 2 is removed.

[0013] In the embodiment, the battery pack 10 is mounted on an automobile. Specifically, the battery pack 10 is mounted between the front wheels and the rear wheels of the automobile. Hereinafter, unless otherwise specified, the battery pack 10 is described as being mounted on an automobile. However, the battery pack 10 is also applicable to uses other than automobiles.

[0014] In each figure, for the purpose of explanation, the X direction, Y direction, and Z direction are shown. The X direction indicates the front-rear direction of the battery pack 10. The Y direction is orthogonal to the X direction. The Y direction indicates the left-right direction of the battery pack 10. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery pack 10. The arrow indicating the X direction, the arrow indicating the Y direction, and the arrow indicating the Z direction respectively indicate the front direction, left direction, and up direction of the battery pack 10. In FIG. 1, the white circle with a black dot indicating the Z direction indicates that the arrow indicating the Z direction extends from the back to the front of the paper surface. In FIG. 2, the white circle with a black dot indicating the X direction indicates that the arrow indicating the X direction extends from the back to the front of the paper surface. However, the relationships between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery pack 10 are not limited to this example.

[0015] In an embodiment, the front-rear direction, left-right direction, and up-down direction of the battery pack 10 are determined by the automobile on which the battery pack 10 is mounted. The X direction, Y direction, and Z direction respectively indicate the front-rear direction, left-right direction, and up-down direction of the automobile. The arrow indicating the X direction, the arrow indicating the Y direction, and the arrow indicating the Z direction respectively indicate the front direction, left direction, and up direction of the automobile. However, the relationships between the front-rear direction, left-right direction, and up-down direction of the battery pack 10 and the front-rear direction, left-right direction, and up-down direction of the automobile are not limited to this example.

[0016] Hereinafter, as necessary, the side indicated by the arrow indicating the X direction is referred to as the +X side, and the opposite side of the side indicated by the arrow indicating the X direction is referred to as the -X side. Hereinafter, as necessary, the side indicated by the arrow indicating the Y direction is referred to as the +Y side, and the opposite side of the side indicated by the arrow indicating the Y direction is referred to as the -Y side. Hereinafter, as necessary, the side indicated by the arrow indicating the Z direction is referred to as the +Z side, and the opposite side of the side indicated by the arrow indicating the Z direction is referred to as the -Z side.

[0017] Referring to FIGS. 1 and 2, the battery pack 10 according to the embodiment will be described.

[0018] As shown in FIG. 1, the battery pack 10 includes a plurality of battery modules 100, a junction box 200, and a pack housing 300.

[0019] In the example shown in FIG. 1, four battery modules 100 are arranged in two rows and two columns in the X direction and the Y direction, respectively. The number and arrangement of the battery modules 100 are not limited to the number and arrangement shown in FIG. 1. For example, the number of battery modules 100 mounted on the battery pack 10 may be only one. Alternatively, the battery pack 10 may include, for example, five or more battery modules 100.

[0020] Each battery module 100 has a plurality of battery cells (not shown) stacked in a direction perpendicular to the Z direction. The plurality of battery cells are electrically connected to each other in series, in parallel, or in a combination of series and parallel. As shown in FIG. 1, each battery module 100 further has a module housing 110 that houses the battery cells (not shown). Each module housing 110 has a substantially rectangular parallelepiped shape. As shown in FIG. 1, when viewed from the Z direction, each module housing 110 has a substantially rectangular shape having a pair of sides substantially parallel to the X direction and a pair of other sides substantially parallel to the Y direction. As shown in FIG. 1, protrusions 112 are provided on both sides in the Y direction of each module housing 110. When viewed from the Z direction, each protrusion 112 extends in the X direction. However, the shape of the protrusion 112 is not limited to the shape shown in FIG. 1.

[0021] As shown in FIG. 1, the junction box 200 is located on the +X side with respect to the two battery modules 100 located on the +X side. The position where the junction box 200 is arranged is not limited to the position shown in FIG. 1. The plurality of battery modules 100 and the junction box 200 are electrically connected by a bus bar (not shown).

[0022] As shown in FIGS. 1 and 2, the pack housing 300 has a lower plate 310, side frames 320, an upper plate 330, and a support frame 340. The pack housing 300 houses a plurality of battery modules 100 and a junction box 200.

[0023] The lower plate 310 has a substantially plate shape that is substantially perpendicular to the Z direction. The plurality of battery modules 100 and the junction box 200 are located on the +Z side with respect to the +Z side surface of the lower plate 310. As shown in FIG. 1, the lower plate 310 has a substantially rectangular shape having a pair of long sides substantially parallel to the X direction and a pair of short sides substantially parallel to the Y direction. The shape of the lower plate 310 is not limited to the example shown in FIG. 1.

[0024] As shown in FIG. 2, each battery module 100 is located on the +Z side with respect to the +Z side surface of the lower plate 310 with a thermal conductive adhesive 150 positioned between the -Z side surface of the module housing 110 and the +Z side surface of the lower plate 310. The -Z side surface of the module housing 110 and the +Z side surface of the lower plate 310 are physically adhered to each other via the thermal conductive adhesive 150 and are thermally coupled to each other via the thermal conductive adhesive 150. Therefore, the thermal conductivity between the battery module 100 and the lower plate 310 can be improved by the thermal conductive adhesive 150. However, the -Z side surface of the module housing 110 and the +Z side surface of the lower plate 310 may be in direct contact with each other without the thermal conductive adhesive 150 being provided.

[0025] The side frames 320 extend from the entire circumference around the Z direction of the +Z side surface of the lower plate 310 toward the +Z side. When viewed from the Z direction, the side frames 320 surround the region where the plurality of battery modules 100 and the junction box 200 are located.

[0026] The upper plate 330 is located on the +Z side with respect to the plurality of battery modules 100, the junction box 200, and the side frame 320. When viewed from the Z direction, the lower plate 310 and the upper plate 330 have substantially the same shape. The side frame 320 and the portion of the upper plate 330 that overlaps the side frame 320 in the Z direction are fastened to each other by a fastener such as a bolt (not shown). With the side frame 320 and the portion of the upper plate 330 that overlaps the side frame 320 in the Z direction being fastened to each other, the lower plate 310, the side frame 320, and the upper plate 330 form an accommodation space for accommodating the plurality of battery modules 100 and the junction box 200.

[0027] As shown in FIG. 1, when viewed from the Z direction, the support frame 340 extends in a frame shape that at least partially surrounds each battery module 100. As shown in FIG. 1, when viewed from the Z direction, the support frame 340 includes an extension 342 located on the +Y side with respect to the battery module 100 on the +Y side, an extension 342 located between the battery module 100 on the +Y side and the battery module 100 on the -Y side, and an extension 342 located on the -Y side with respect to the battery module 100 on the -Y side. When viewed from the Z direction, each extension 342 extends in the X direction. As shown in FIG. 2, each protrusion 112 is located on the +Z side with respect to the +Z side surface of each extension 342. Each protrusion 112 and each extension 342 are fastened to each other by a fastener such as a bolt (not shown). With each protrusion 112 and each extension 342 being fastened to each other, each battery module 100 and the pack housing 300 are attached to each other.

[0028] FIG. 3 is a perspective view of the side wall plate 322 of the side frame 320 according to the embodiment and its periphery. FIG. 4 is a front view of the through hole 324 of the side wall plate 322 according to the embodiment and its periphery. FIG. 5 is a cross-sectional view taken along line B-B of FIG. 4 in a state where the cable 400 penetrates through the through hole 324 of the side wall plate 322 according to the embodiment. In FIG. 5, the white circle with a black dot indicating the Y direction indicates that the arrow indicating the Y direction extends from the back to the front of the paper surface.

[0029] As shown in Fig. 3, the side frame 320 according to this embodiment includes a side wall plate 322. The side wall plate 322 is a portion on the +X side of the side frame 320. The side wall plate 322 has a generally plate shape that is generally perpendicular to the X direction and extends in the Y direction. As shown in Figs. 3 and 5, the side wall plate 322 includes a first side surface 322a on the +X side of the side wall plate 322 and a second side surface 322b on the -X side of the side wall plate 322.

[0030] The side wall plate 322 according to the embodiment is made of a metal such as aluminum. The side wall plate 322 according to the embodiment is an extrusion-molded product. In the extrusion molding for forming the side wall plate 322, the metal forming the side wall plate 322 is extruded in a direction corresponding to the Y direction of the side wall plate 322 shown in FIGS. 3 to 5. However, the method for forming the side wall plate 322 is not limited to extrusion molding. Hereinafter, unless otherwise specified, the side wall plate 322 according to the embodiment will be described as an extrusion-molded product.

[0031] For example, when the battery pack 10 is mounted in an automobile, the side wall plate 322 may receive an impact from the +X side of the side wall plate 322. Therefore, the side wall plate 322 needs to have enough strength to protect the battery module 100 from an impact received from the +X side of the side wall plate 322. To reduce the weight of the side wall plate 322, the side wall plate 322 may define a hollow space. If the side wall plate 322 is a casting that defines a hollow space, holes are formed to remove cores that define the hollow space of the casting. In this case, the hollow space of the side wall plate 322 may be an open space due to the holes in a cross section perpendicular to the Y direction of the side wall plate 322. In contrast, if the side wall plate 322 is an extrusion-molded product that defines a hollow space, the hollow space of the side wall plate 322 can be a closed space that is continuous in the Y direction. Therefore, when the side wall plate 322 is an extrusion molded product rather than a casting, and the hollow space of the side wall plate 322 has the same size and the cross-sectional area perpendicular to the Y direction of the side wall plate 322 is the same, the section modulus of the side wall plate 322 can be increased. Furthermore, when the side wall plate 322 is an extrusion molded product rather than a casting, and the section modulus of the side wall plate 322 is the same, the weight of the side wall plate 322 can be reduced.

[0032] As shown in FIGS. 3 to 5, the side wall plate 322 defines a through hole 324. The through hole 324 penetrates the side wall plate 322 in the X direction from one of the first side surface 322a and the second side surface 322b to the other. The through hole 324 is formed in the side wall plate 322 after the side wall plate 322 is formed by extrusion molding. As shown in FIG. 5, the battery pack 10 may include a cable 400. In the example shown in FIG. 5, a part of the cable 400 penetrates the through hole 324, and the cable 400 is drawn out from the accommodation space formed by the lower plate 310, the side frame 320, and the upper plate 330. The cable 400 is electrically connected to at least one of, for example, the battery module 100 and the junction box 200. However, the through hole 324 may be used not to draw out the cable 400 but to draw out other members constituting the battery pack 10.

[0033] As shown in FIGS. 4 and 5, the pack housing 300 has a reinforcing member 350. The reinforcing member 350 at least partially covers the through hole 324. In the example shown in FIGS. 4 and 5, the reinforcing member 350 has a substantially cylindrical shape extending in the X direction. In the example shown in FIGS. 4 and 5, the reinforcing member 350 covers the inner peripheral surface around the through hole 324 in the X direction except for the end portion on the -X side of the through hole 324. The strength of the peripheral portion of the through hole 324 in the side wall plate 322 may be reduced by the through hole 324. However, since the reinforcing member 350 at least partially covers the through hole 324, the strength of the peripheral portion of the through hole 324 in the side wall plate 322 can be improved as compared with the case where the reinforcing member 350 is not provided. The position where the reinforcing member 350 is provided is not limited to the example shown in FIGS. 4 and 5. For example, the reinforcing member 350 may cover the inner peripheral surface around the through hole 324 in the X direction at the end portion on the -X side of the through hole 324.

[0034] The reinforcing member 350 according to the embodiment is, for example, a metal such as aluminum. The reinforcing member 350 according to the embodiment is a cast molded product. When the reinforcing member 350 is formed by casting, it is possible to facilitate the molding of a relatively complex shape such as a substantially cylindrical shape of the reinforcing member 350 as compared with the case where the reinforcing member 350 is formed by a method different from casting. However, the reinforcing member 350 may be formed by a method different from casting.

[0035] In the example shown in FIG. 5, the reinforcing member 350 includes an end portion 352 that protrudes toward the +X side from the first side surface 322a. In the examples shown in FIGS. 4 and 5, a portion around the X-direction of one end on the +X side of the through-hole 324 of the first side surface 322a and an outer peripheral surface around the X-direction of the end portion 352 are welded to each other. Therefore, a welded portion 360 is formed between the portion of the first side surface 322a and the outer peripheral surface of the end portion 352.

[0036] In the examples shown in FIGS. 4 and 5, a portion around the X-direction of one end on the +X side of the through-hole 324 of the first side surface 322a and an outer peripheral surface around the X-direction of the end portion 352 are joined to each other via the welded portion 360. Tools for welding the side wall plate 322 and the reinforcing member 350 to each other are more easily positioned outside the through-hole 324 than inside the through-hole 324. Therefore, in the examples shown in FIGS. 4 and 5, as compared with the case where the inner peripheral surface around the X-direction of the through-hole 324 of the side wall plate 322 and the outer peripheral surface around the X-direction of the reinforcing member 350 are welded to each other, the joining of the side wall plate 322 and the reinforcing member 350 can be facilitated. However, the inner peripheral surface around the X-direction of the through-hole 324 of the side wall plate 322 and the outer peripheral surface around the X-direction of the reinforcing member 350 may be welded to each other.

[0037] As shown in FIG. 4, the welded portion 360 is provided on the entire circumference around the X direction of the reinforcing member 350. Therefore, by the welded portion 360, the portion around the X direction of one end on the +X side of the through hole 324 on the first side surface 322a and the outer peripheral surface around the X direction of the end portion 352 are sealed to each other. Thus, the sealing performance of the peripheral portion of the through hole 324 of the side wall plate 322 can be improved as compared with the case where the said portion of the first side surface 322a and the said outer peripheral surface of the end portion 352 are not sealed to each other. The sealing positions of the side wall plate 322 and the reinforcing member 350 are not limited to the examples shown in FIGS. 4 and 5. The side wall plate 322 and the reinforcing member 350 can be at least partially sealed to each other.

[0038] In addition to, or instead of, one end on the +X side of the through hole 324, the side wall plate 322 and the reinforcing member 350 may be joined to each other at the other end on the -X side of the through hole 324. For example, the reinforcing member 350 may include an end portion protruding toward the -X side from the second side surface 322b. The portion around the X direction of the other end on the -X side of the through hole 324 on the second side surface 322b and the outer peripheral surface around the X direction of the end portion on the -X side of the reinforcing member 350 may be joined to each other via a welded portion. When the side wall plate 322 and the reinforcing member 350 are joined to each other via a welded portion at the other end on the -X side of the through hole 324, the joining of the side wall plate 322 and the reinforcing member 350 can be facilitated as compared with the case where the inner peripheral surface around the X direction of the through hole 324 of the side wall plate 322 and the outer peripheral surface around the X direction of the reinforcing member 350 are welded to each other. Further, when the side wall plate 322 and the reinforcing member 350 are joined to each other via a welded portion at the other end on the -X side of the through hole 324, the welded portion can seal the portion around the X direction of the other end on the -X side of the through hole 324 on the second side surface 322b and the outer peripheral surface around the X direction of the end portion on the -X side of the reinforcing member 350 to each other.

[0039] In the embodiment, it has been described that the side wall plate 322 of the side frame 320 is reinforced by the reinforcing member 350. However, the positions where the reinforcing member can be applied are not limited to the side wall plate 322, and also include other parts of the pack housing 300. For example, when the pack housing 300 has an extruded product that defines a through hole, a cast product may at least partially cover the through hole of the extruded product as the reinforcing member. In this example, the extruded product and the cast product may be at least partially welded to each other or at least partially sealed to each other.

[0040] FIG. 6 is a cross-sectional view of the side wall plate 322 and the reinforcing member 350A according to Modification 1. FIG. 6 corresponds to FIG. 5 of the embodiment. The reinforcing member 350A according to Modification 1 is the same as the reinforcing member 350 according to the embodiment, except for the following points.

[0041] The reinforcing member 350A according to Modification 1 includes an extending portion 352A, a first end portion 354A, and a second end portion 356A. The extending portion 352A extends from one of the first side surface 322a and the second side surface 322b to the other. The first end portion 354A is provided at the +X side end portion of the extending portion 352A. The first end portion 354A covers a portion around the +X side end of the through hole 324 in the X direction on the first side surface 322a. The portion on the first side surface 322a and the -X side surface of the first end portion 354A are welded to each other. Therefore, a first welded portion 362A is formed between the portion on the first side surface 322a and the surface of the first end portion 354A. The second end portion 356A is provided at the -X side end portion of the extending portion 352A. The second end portion 356A protrudes -X side from the second side surface 322b. The portion around the -X side other end of the through hole 324 in the X direction on the second side surface 322b and the outer peripheral surface around the X direction of the second end portion 356A are welded to each other. Therefore, a second welded portion 364A is formed between the portion on the second side surface 322b and the outer peripheral surface of the second end portion 356A. In Modification 1, with the first end portion 354A facing the +X side and the second end portion 356A facing the -X side, the reinforcing member 350A can be inserted into the through hole 324 from the +X side end of the through hole 324.

[0042] Also in Modification 1, the strength of the peripheral portion of the through hole 324 in the side wall plate 322 can be improved by the reinforcing member 350A. Also in Modification 1, compared with the case where the inner peripheral surface around the X direction of the through hole 324 of the side wall plate 322 and the outer peripheral surface around the X direction of the reinforcing member 350A are welded to each other, the joining of the side wall plate 322 and the reinforcing member 350A can be facilitated. Further, in Modification 1, the first welding portion 362A can seal the portion around the X direction of one end on the +X side of the through hole 324 of the first side surface 322a and the surface on the -X side of the first end portion 354A with each other. Also, the second welding portion 364A can seal the portion around the X direction of the other end on the -X side of the through hole 324 of the second side surface 322b and the outer peripheral surface around the X direction of the second end portion 356A with each other.

[0043] FIG. 7 is a front view of the side wall plate 322B and the reinforcing member 350B according to Modification 2. FIG. 7 corresponds to FIG. 4 of the embodiment. The side wall plate 322B and the reinforcing member 350B according to Modification 2 are the same as the side wall plate 322 and the reinforcing member 350 according to the embodiment, respectively, except for the following points.

[0044] The side wall plate 322B according to Modification 2 defines a first through hole 324B1, a second through hole 324B2, and a third through hole 324B3. The arrangement and shape of each through hole are not limited to the example shown in FIG. 7. In Modification 2, a single reinforcing member 350B at least partially covers a plurality of through holes including the first through hole 324B1, the second through hole 324B2, and the third through hole 324B3. Similar to the embodiment, the side wall plate 322B and the reinforcing member 350B may be at least partially welded to each other or at least partially sealed to each other. Also in Modification 2, the strength of the peripheral portions of the first through hole 324B1, the second through hole 324B2, and the third through hole 324B3 of the side wall plate 322B can be improved by the reinforcing member 350B. Further, in Modification 2, the joining of the side wall plate 322B and the reinforcing member 350B can be facilitated as compared with the case where separate reinforcing members separately cover the first through hole 324B1, the second through hole 324B2, and the third through hole 324B3.

Description of Reference Numerals

[0045] 10 Battery pack, 100 Battery module, 110 Module housing, 112 Protrusion, 150 Thermally conductive adhesive, 200 Junction box, 300 Pack housing, 310 Lower plate, 320 Side frame, 322, 322B Side wall plate, 322a First side, 322b Second side, 324 Through hole, 324B1 First through hole, 324B2 Second through hole, 324B3 Third through hole, 330 Upper plate, 340 Support frame, 342 Extending body, 350, 350A, 350B Reinforcing member, 352 End portion, 352A Extending portion, 354A First end portion, 356A Second end portion, 360 Welded portion, 362A First welded portion, 364A Second welded portion, 400 Cable

Claims

1. A battery module, a housing that houses the battery module, and the housing includes a first member that defines a through hole and a second member that at least partially covers the through hole, a battery pack.

2. The battery pack according to claim 1, wherein the first member is an extruded product.

3. The battery pack according to claim 2, wherein the second member is a cast product.

4. The battery pack according to any one of claims 1 to 3, wherein the first member and the second member are at least partially welded to each other.

5. The battery pack according to any one of claims 1 to 3, wherein the first member and the second member are at least partially sealed to each other.

6. The battery pack according to any one of claims 1 to 3, wherein a portion located at at least one of both ends of the through hole of the first member and the second member are joined to each other.

7. The battery pack according to any one of claims 1 to 3, further comprising a cable passing through the through hole.

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