Battery pack

Abstract

To provide a battery pack that enables increase in rigidity of a case body.SOLUTION: A battery pack 100 includes a plurality of battery modules 51, and a case body 21 forming a space 23 where the plurality of battery modules 51 is housed. The case body 21 includes a bottom portion 26, a side portion 31 erected from the bottom portion 26 and surrounding the space 23, a boss portion 36 connected to the side portion 31 outside of the space 23 and used to fasten the case body 21, and a rib portion 41 extending between the plurality of battery modules 51 adjacent to each other and connected to the side portion 31 in the space 23. The boss portion 36 and the rib portion 41 are opposite to each other with the side portion 31 interposed therebetween.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2020-35554 (Patent Document 1) discloses a battery pack including a drive battery for an electric vehicle and a battery case that houses the battery. The battery case has a case bottom wall, a case front wall, a case rear wall, and left and right case side walls that stand up from the outer periphery of the case bottom wall, and a cross member that consists of a collection of many ribs that stand up from the case bottom wall and connects the left and right case side walls. Cylindrical fixing parts are provided on the outer surfaces of the left and right case side walls in the vehicle width direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-35554 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery pack disclosed in the aforementioned Patent Document 1, the battery case is fixed to the underside of the vehicle floor using a bolt inserted into a cylindrical fixing portion. In such a battery pack, an excessive load is applied to the battery case via the cylindrical fixing portion when the vehicle suddenly accelerates or decelerates, or when the vehicle makes a sharp turn. For this reason, the battery case is required to have high rigidity to withstand such loads.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a battery pack in which the rigidity of the case body is increased. [Means for solving the problem]

[0006] [1] A battery pack comprising: a plurality of battery modules; and a case body that forms a space to house the plurality of battery modules, the case body having a bottom portion, side portions that rise from the bottom portion and surround the space, boss portions that are connected to the side portions outside the space and are used to fasten the case body, and rib portions that extend between the plurality of adjacent battery modules and are connected to the side portions inside the space, the boss portions and the rib portions facing each other across the side portions.

[0007] In a battery pack configured in this manner, bosses and ribs are connected to the side portions from the outside and inside of the space that houses the battery modules, respectively, and these bosses and ribs are arranged opposite each other across the side portion. This configuration allows for a case body that exhibits high rigidity even when an excessive load is applied to the case body via the bosses that fasten the case body.

[0008] [2] The battery pack described in [1], wherein the bottom has a rectangular shape when viewed in a plane, the side rises from the peripheral edge of the bottom, and the case body has a plurality of rib portions that extend in a lattice pattern inside the space when the bottom is viewed in a plane, each connected at an angle of 90° to the side, and a plurality of boss portions that face the plurality of rib portions across the side and extend in a direction perpendicular to the bottom.

[0009] In a battery pack configured in this manner, multiple boss portions are arranged opposite multiple rib portions arranged in a grid pattern, with the sides sandwiched between them, thereby further increasing the rigidity of the case body.

[0010] [3] The battery pack according to [1] or [2], wherein the case body is made of metal, and the bottom, side, boss, and rib are integrally formed with one another.

[0011] In a battery pack configured in this manner, the bottom, side, boss, and ribs are integrally formed from metal, which further increases the rigidity of the case body. [Effects of the Invention]

[0012] As described above, according to the present invention, it is possible to provide a battery pack in which the rigidity of the case body is increased. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an exploded view showing a battery pack according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view showing the battery pack as seen in the direction of the arrows on line II-II in FIG. 1. [Figure 3] 3 is a cross-sectional view showing the battery pack as seen in the direction of the arrows on line III-III in FIG. 1. [Figure 4] 4 is an enlarged top view showing the area surrounded by the two-dot chain line IV in FIG. 1. FIG. [Figure 5] 1. FIG. 4 is a top view showing a first modified example of the case body in FIG. [Figure 6] 1. FIG. 4 is a cross-sectional view showing a second modified example of the case body in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0015] Fig. 1 is an exploded view showing a battery pack according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing the battery pack as seen in the direction of the arrows on line II-II in Fig. 1. Fig. 3 is a cross-sectional view showing the battery pack as seen in the direction of the arrows on line III-III in Fig. 1.

[0016] 1 to 3, a battery pack 100 is mounted on a vehicle 110 such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV). The battery pack 100 is used as a power source for driving the vehicle 110.

[0017] The battery pack 100 has a plurality of battery modules 51. Each battery module 51 is composed of a plurality of battery cells (not shown) stacked in one direction and electrically connected in series. Each battery cell is composed of a rectangular lithium-ion battery.

[0018] In this specification, for convenience in explaining the structure of battery pack 100, an axis that corresponds to the stacking direction of multiple battery cells and extends horizontally is referred to as the "Y axis," an axis that is perpendicular to the Y axis and extends horizontally is referred to as the "X axis," and an axis that extends vertically is referred to as the "Z axis." Battery pack 100 is typically mounted on vehicle 110 so that one of the X axis direction and the Y axis direction corresponds to the front-to-rear direction of vehicle 110, and the other of the X axis direction and the Y axis direction corresponds to the left-to-right direction of vehicle 110.

[0019] The battery pack 100 further includes a case body 21. The case body 21 is made of metal. For example, the case body 21 is formed from aluminum. The case body 21 is generally a box-shaped body that opens upward and has a rectangular parallelepiped appearance. The case body 21 forms a space 23 that houses a plurality of battery modules 51. The plurality of battery modules 51 are arranged in a matrix in the space 23 so as to be spaced apart from one another in the X-axis direction and the Y-axis direction.

[0020] The plurality of battery modules 51 are not limited to being arranged in the matrix form described above, but may be arranged in a line in either the X-axis direction or the Y-axis direction.

[0021] The battery pack 100 further includes a lid 61. The lid 61 is made of a plate material arranged parallel to the X-axis-Y-axis plane, with the Z-axis direction (vertical direction) being the thickness direction. The lid 61 is provided to close the opening of the case body 21. The lid 61 is fastened to a plurality of ribs 41 (described later) using bolts (not shown).

[0022] The case body 21 has a bottom 26 and side portions 31. The bottom 26 has a wall shape with its thickness direction in the Z-axis direction and arranged parallel to the X-axis-Y-axis plane. The bottom 26 has a rectangular shape in a plan view seen in the Z-axis direction. A plurality of battery modules 51 are placed on the bottom 26.

[0023] The side portion 31 rises from the bottom portion 26 and surrounds the space 23. The side portion 31 rises from the peripheral edge of the bottom portion 26 when viewed from above.

[0024] The side portions 31 include a pair of side portions 31s and 31t, and a pair of side portions 31m and 31n. The pair of side portions 31s and 31t face each other in the Y-axis direction, with the space 23 in between. Each of the side portions 31 of the side portions 31s and 31t has a wall shape that is parallel to the X-axis plane, with the Y-axis direction being its thickness direction. The pair of side portions 31m and 31n face each other in the X-axis direction, with the space 23 in between. Each of the side portions 31 of the side portions 31m and 31n has a wall shape that is parallel to the Y-axis plane, with the X-axis direction being its thickness direction.

[0025] The case body 21 further has rib portions 41. The rib portions 41 are provided inside the space 23. The rib portions 41 extend between adjacent battery modules 51. The rib portions 41 rise from the bottom portion 26 and extend in a rib-like manner in one direction parallel to the horizontal direction.

[0026] The case body 21 has a plurality of rib portions 41. The plurality of rib portions 41 includes a plurality of rib portions 41p and a plurality of rib portions 41q.

[0027] The rib portion 41p has a rib shape extending in the Y-axis direction, with the thickness direction being the X-axis direction. One end of the rib portion 41p extending in the Y-axis direction is connected to the side portion 31s, and the other end of the rib portion 41p extending in the Y-axis direction is connected to the side portion 31t. The rib portion 41p is connected to each of the side portions 31s and 31t at an angle of 90°. The multiple rib portions 41p are provided at intervals from each other in the X-axis direction. The multiple rib portions 41p are provided side by side at equal intervals in the X-axis direction. The rib portions 41p are arranged between multiple battery modules 51 adjacent to each other in the X-axis direction.

[0028] Of the multiple rib portions 41p, the rib portion 41p located at one end in the X-axis direction extends in the Y-axis direction along the side portion 31m. Of the multiple rib portions 41p, the rib portion 41p located at the other end in the X-axis direction extends in the Y-axis direction along the side portion 31n.

[0029] The rib portion 41q has a rib shape extending in the X-axis direction, with the Y-axis direction being the thickness direction. One end of the rib portion 41q extending in the X-axis direction is connected to the side portion 31m, and the other end of the rib portion 41q extending in the X-axis direction is connected to the side portion 31n. The rib portion 41q is connected to each of the side portions 31m and 31n at an angle of 90°. The multiple rib portions 41q are provided at intervals from each other in the Y-axis direction. The multiple rib portions 41q are provided side by side at equal intervals in the Y-axis direction. The rib portions 41q are arranged between multiple battery modules 51 adjacent to each other in the Y-axis direction.

[0030] The plurality of rib portions 41 extend in a lattice pattern inside the space 23. The plurality of rib portions 41p and the plurality of rib portions 41q intersect with each other at an angle of 90°.

[0031] Fig. 4 is a top view showing the case body in the area surrounded by the two-dot chain line IV in Fig. 1. Note that, hereinafter, the structure of case body 21 will be described with reference to boss portion 36s and rib portion 41p connected to side portion 31s in Figs. 2 to 4, but the relative positions of boss portion 36s and rib portion 41 are the same for each of side portions 31s, 31t, 31m, and 31n.

[0032] 1 to 4, the case body 21 further has a boss portion 36 for fastening the case body 21. The boss portion 36 is connected to the side portion 31 outside the space 23.

[0033] The boss portion 36 protrudes from the outer surface of the side portion 31 disposed outside the space 23. The boss portion 36 extends axially in the vertical direction. The length of the boss portion 36 in the Z-axis direction is the same as the length of the side portion 31 in the Z-axis direction.

[0034] 2 and 3, the top surface 32 of the side portion 31 and the boss portion 36 forms a step with the top surface 42 of the rib portion 41. A lid body 61 is disposed in the step formed by the top surface 32 and the top surface 42. The length of the boss portion 36 in the Z-axis direction is greater than the length of the rib portion 41 in the Z-axis direction.

[0035] The case body 21 has a plurality of boss portions 36. The plurality of boss portions 36 include a plurality of boss portions 36s, a plurality of boss portions 36t, a plurality of boss portions 36m, and a plurality of boss portions 36n.

[0036] The boss portion 36s is connected to the side portion 31s. The plurality of boss portions 36s are provided at intervals in the X-axis direction. The boss portion 36t is connected to the side portion 31t. The plurality of boss portions 36t are X-axis direction The boss portions 36m are spaced apart from one another in the Y-axis direction. The boss portion 36m is connected to the side portion 31m. The boss portions 36m are spaced apart from one another in the Y-axis direction. The boss portion 36n is connected to the side portion 31n. The boss portions 36n are spaced apart from one another in the Y-axis direction.

[0037] As shown in Figures 2 and 3, the case body 21 is fastened to the floor 120 of the vehicle 110 via the boss portion 36. A bolt insertion hole 37 is provided in the boss portion 36. The bolt insertion hole 37 is a through-hole that penetrates the boss portion 36 in the Z-axis direction. The case body 21 is assembled to the vehicle 110 so that the top surface 32 abuts against the floor 120. A bolt 56 is inserted into the bolt insertion hole 37 from below the boss portion 36. The bolt 56 inserted into the bolt insertion hole 37 is screwed into the floor 120, thereby fastening the case body 21 to the vehicle 110.

[0038] As shown in FIG. 4, the bolt insertion hole 37 has a circular opening shape centered on the central axis 210. The boss portion 36 (36s) has a fastening portion 38 and a base portion 39. The fastening portion 38 corresponds to the fastening portion of the boss portion 36 (36s) to the vehicle 110. The fastening portion 38 is provided with the bolt insertion hole 37. The fastening portion 38 has a cylindrical shape centered on the central axis 210. The base portion 39 corresponds to the base portion of the boss portion 36 (36s) protruding from the side portion 31 (31s). The base portion 39 is provided between the side portion 31 (31s) and the fastening portion 38.

[0039] The base 39 is provided so that the width of the base 39 in the X-axis direction increases as it approaches the side portion 31 (31s) from the central axis 210 in the Y-axis direction. The base 39 may have a constricted shape so that the width of the base 39 in the X-axis direction decreases as it approaches the side portion 31 (31s) from the central axis 210 in the Y-axis direction, and further increases as it approaches the side portion 31 (31s).

[0040] The case body 21 is made of die-cast metal (aluminum die-cast). The bottom portion 26, the side portion 31, the boss portion 36, and the rib portion 41 are integrally formed from metal.

[0041] As shown in FIGS. 1 and 4, the boss portion 36 and the rib portion 41 face each other across the side portion 31. The multiple boss portions 36s face each of the multiple rib portions 41p across the side portion 31s. The multiple boss portions 36t face each of the multiple rib portions 41p across the side portion 31t. The multiple boss portions 36m face each of the multiple rib portions 41q across the side portion 31m. The multiple boss portions 36n face each of the multiple rib portions 41q across the side portion 31n.

[0042] As shown in FIG. 4, the boss portion 36 (36s) is connected to the side portion 31 (31s) in a first range Ha in the X-axis direction. The rib portion 41 (41p) is connected to the side portion 31 (31s) in a second range Hb in the X-axis direction. The first range Ha in the X-axis direction is larger than the second range Hb in the X-axis direction. The boss portion 36 and the rib portion 41 are provided such that a portion of the first range Ha and the entire second range Hb overlap each other. A center line 220 of the rib portion 41 (41p), which bisects the second range Hb in the X-axis direction and extends in the Y-axis direction, intersects with the central axis 210 of the bolt insertion hole 37.

[0043] When vehicle 110 suddenly accelerates or decelerates, or makes a sharp turn, an excessive load is applied to case body 21 via boss portion 36. In response to this, in the present embodiment, boss portion 36 and rib portion 41 are connected to side portion 31 from the outside and inside of space 23 that houses multiple battery modules 51, respectively, and boss portion 36 and rib portion 41 are configured to face each other across side portion 31, thereby realizing case body 21 that exhibits high rigidity against such loads.

[0044] For example, let us consider a case in which a load in the Y-axis direction is applied to the case body 21 in Fig. 1 via the boss portion 36s. In this case, the load is applied to the boss portion 36s, the side portion 31s, the rib portion 41p, the side portion 31t, and the Boss part 36t By receiving the load integrally, deformation or damage to the case body 21 can be prevented.

[0045] In addition, since the rib portion 41 serves both to partition the space 23 that houses multiple battery modules 51 and to increase the rigidity of the case body 21, it is possible to make the case body 21 smaller or lighter, and to simplify the structure of the case body 21.

[0046] In this embodiment, the plurality of bosses 36 are arranged opposite the plurality of ribs 41 arranged in a grid pattern, with the side portion 31 in between. This configuration further increases the rigidity of the case body 21, and makes it possible to realize a case body 21 that exhibits high rigidity against loads from various directions.

[0047] In the present embodiment, bottom 26, side 31, boss 36, and rib 41 are integrally formed from metal. This configuration eliminates the need for welds between bottom 26, side 31, boss 36, and rib 41, further increasing the rigidity of case body 21. It also increases the airtightness of space 23 that houses multiple battery modules 51.

[0048] Fig. 5 is a top view showing a first modified example of the case body in Fig. 1. Fig. 5 corresponds to Fig. 4. Referring to Fig. 5, in this modified example, the boss portion 36 and the rib portion 41 are provided so that a part of the first area Ha and a part of the second area Hb overlap each other. The center line 220 of the rib portion 41 (41p) and the center axis 210 of the bolt insertion hole 37 are misaligned in the X-axis direction.

[0049] When at least a part of the first area Ha and at least a part of the second area Hb overlap with each other, the boss portion 36 (36s) and the rib portion 41 (41p) face each other with the side portion 31 (31s) interposed therebetween.

[0050] Fig. 6 is a cross-sectional view showing a second modified example of the case body in Fig. 1. Referring to Fig. 6, in this modified example, the length of boss portion 36 in the Z-axis direction is smaller than the length of rib portion 41 in the Z-axis direction.

[0051] As exemplified in this modification, the shape of boss portion 36 for fastening case body 21 to vehicle 110 is not particularly limited. For example, boss portion 36 and rib portion 41 may be configured so that top surface 32 and top surface 42 are flush with each other. Boss portion 36 may have a C-shaped cross section when cut along the X-axis-Y-axis plane, into which a fastening means such as a bolt can be inserted.

[0052] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0053] 21 case body, 23 space, 26 bottom, 31, 31m, 31n, 31s, 31t side, 32, 42 top surface, 36, 36m, 36n, 36s, 36t boss portion, 37 bolt insertion hole, 38 fastening portion, 39 base, 41, 41p, 41q rib portion, 51 battery module, 56 bolt, 61 lid body, 100 battery pack, 110 vehicle, 120 floor portion, 210 central axis, 220 center line, Ha first range, Hb second range.

Claims

1. a plurality of battery modules; a case body that forms a space for accommodating a plurality of the battery modules, The case body is The bottom and a side portion rising from the bottom portion and surrounding the space; a boss portion connected to the side portion outside the space and for fastening the case body; a rib portion extending between the adjacent battery modules and connected to the side portion inside the space; the boss portion and the rib portion face each other across the side portion, The bottom portion has a rectangular shape in a plan view, the side portions rise from the peripheral edge of the bottom portion; The case body is When the bottom portion is viewed from above, a plurality of the rib portions extend in a lattice pattern inside the space and are each connected at an angle of 90° to the side portion; The battery pack has a plurality of boss portions that face the plurality of rib portions with the side portion between them and each boss portion extends in a direction perpendicular to the bottom portion.

2. A plurality of battery modules; a case body that forms a space for accommodating a plurality of the battery modules, The case body is The bottom and a side portion rising from the bottom portion and surrounding the space; a boss portion connected to the side portion outside the space and for fastening the case body; a rib portion extending between the adjacent battery modules and connected to the side portion inside the space; the boss portion and the rib portion face each other across the side portion, The case body is made of metal, The battery pack, wherein the bottom portion, the side portion, the boss portion, and the rib portion are integrally molded with one another.

Images