Battery pack

Abstract

To provide a battery pack with which it is possible to protect a battery module, as well as reduce component counts and the device weight.SOLUTION: A battery pack 10 attached under the floor of a vehicle body 1 comprises two battery modules 11 juxtaposed in a longitudinal direction, and a battery case 20 having a cross member 50 extending in a lateral direction. The cross member 50 includes an upper cross member 52, a lower cross member 51 located at a position overlapping the upper cross member 52 as seen in a vertical direction, and a bolt-fixing part 53 which is in contact with the bottom face of a case body 21 and fixes the upper cross member 52 and the lower cross member 51 to each other with a bolt B3. A first protrusion 321 protruding downward and extending continuously in the longitudinal direction is provided integrally to the bottom face of the case body 21, and the first protrusion 321 intersects the cross member 50 at a position overlapping the bolt-fixing part 53 as seen from the vertical direction.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a battery pack that is mounted under a floor of a vehicle body. [Background technology]

[0002] In recent years, research and development has been conducted on secondary batteries (hereafter referred to as batteries) that contribute to energy efficiency in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Electric vehicles such as battery-powered electric vehicles are equipped with large-capacity batteries. The battery is housed in a case and attached, for example, below the floor panel of the vehicle body, but if a curb, flying stone, or other object strikes the case from below while the vehicle is moving, a structure is required to protect the battery from the load input caused by the collision.

[0004] In contrast, for example, in the vehicle underbody structure described in Patent Document 1, a protective plate is disposed under the battery case, and a protrusion is provided on the bottom plate of the battery case or on the protective plate at a position below the intermediate plate of the battery stack. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-138187 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, a protective plate is placed under the battery case to protect the battery stack, but this increases the number of parts and the weight of the vehicle. There is a demand for a system that can protect the battery while reducing the number of parts and weight.

[0007] The present invention provides a battery pack that can protect a battery module while reducing the number of parts and the weight. [Means for solving the problem]

[0008] The present invention relates to A battery pack that is mounted under the floor of a vehicle body, a battery module including a plurality of battery cells stacked in a first direction among horizontal directions, at least two of which are arranged side by side in a second direction among the horizontal directions perpendicular to the first direction; A case that houses the battery module, The case is a case body on which the battery module is placed; a cross member extending in the first direction inside the case and provided between the at least two battery modules arranged side by side in the second direction; The cross member is The upper cross member, A lower cross member is disposed below the upper cross member in a position overlapping the upper cross member when viewed from the up-down direction; a fastening portion that abuts against a bottom surface of the case body and fastens the upper cross member and the lower cross member to each other with a fastening member; At least one first protrusion is integrally provided on a bottom surface of the case body, protruding downward and continuously extending in the second direction, The first protrusion intersects with the cross member at a position overlapping with the fixed portion of the cross member when viewed from the up-down direction. Effect of the Invention

[0009] According to the present invention, it is possible to protect the battery module while reducing the number of parts and the weight of the vehicle. [Brief description of the drawings]

[0010] [Figure 1]1 is a perspective view of a battery pack 10 attached to a vehicle body 1. FIG. [Diagram 2] FIG. 2 is an exploded perspective view of the battery pack 10. [Diagram 3] 2 is a partial perspective view of the battery module 11 as viewed from the cover plate 15 side. FIG. [Figure 4] FIG. 2 is a top view of the battery module 11. [Diagram 5] FIG. 2 is an enlarged perspective view of the cross member 50. [Figure 6] 1 is a top view showing the positional relationship between the cross member 50 and the front and rear battery modules 11. FIG. [Figure 7] 7 is a cross-sectional view taken along line AA in FIG. 6. [Figure 8] 7 is a cross-sectional view taken along line BB in FIG. 6. [Figure 9] FIG. 2 is a top view of the battery pack 10 with the cover 22 removed. [Figure 10] FIG. 2 is a bottom view of the battery pack 10. [Figure 11] 10 is a cross-sectional view taken along line CC in FIG. 9. [Figure 12] 10 is a cross-sectional view taken along line DD in FIG. 9. [Figure 13] 1 shows this embodiment (upper row) in which the third protrusion 327 is provided between the water jacket 70 and the rear frame 41, and a comparative example (lower row) in which the third protrusion 327 is provided directly below the rear frame 41. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A battery pack according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The drawings are to be viewed in the direction of the reference symbols, and in the following description, the front-rear, left-right, and up-down directions are described according to the direction as seen by the driver of the vehicle. In the drawings, the front of the vehicle is indicated as Fr, the rear as Rr, the left as L, the right as R, the top as U, and the bottom as D.

[0012] 1 is a perspective view of a battery pack 10 attached under the floor of a vehicle body 1. In this embodiment, for example, the battery pack 10 is attached under a floor panel 3 of the vehicle body 1. The vehicle to which the battery pack 10 is attached is, for example, an electric vehicle such as a battery-powered electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0013] The floor panel 3 has a plurality of (four here) bolt holes 4 arranged side by side in the left-right direction. The bolt holes 4 are part of a fixing portion that fixes the battery pack 10 to the floor panel 3. A bolt B3 of a bolt fixing portion 53 (described later) is inserted into the bolt hole 4, and the battery pack 10 is fixed to the floor panel 3 by fastening the bolt B3 to the bolt fixing portion 53.

[0014] 2 is an exploded perspective view of the battery pack 10. The battery pack 10 includes four battery modules 11, a junction box 17, a battery ECU (Electronic Control Unit) 18, a battery case 20 that houses these, and a water jacket 70.

[0015] (Battery module) The four battery modules 11 are arranged in two rows in the front-rear direction and two rows in the left-right direction. The four battery modules 11 are electrically connected to each other via electrical connection members (e.g., bus bars) not shown. The battery modules 11 store electric power to be supplied to a motor or the like that serves as a drive source for the vehicle. The number of battery modules 11 can be set arbitrarily, and the arrangement is not particularly limited.

[0016] 3 and 4 are respectively a partial perspective view and a top view of a battery module 11. Each battery module 11 includes a plurality of battery cells 110, an intermediate plate 12, a pair of end plates 13, a pair of restraining members 14, and a pair of cover plates 15.

[0017] The battery cell 110 is, for example, a laminated type cell made of a solid-state battery. In this embodiment, a plurality of battery cells 110 are stacked in the left-right direction. The laminated type cell has a positive electrode connected to a positive electrode tab, a negative electrode connected to a negative electrode tab, a solid electrolyte disposed between the positive electrode and the negative electrode, and a laminated film that accommodates these, and charges and discharges by exchanging ions (e.g., lithium ions) between the positive electrode and the negative electrode via the solid electrolyte. Each battery cell 110 is not limited to a laminated type, and may be a square or cylindrical type, and the electrolyte may be liquid or solid.

[0018] The intermediate plate 12 is provided at the middle in the stacking direction (here, the left-right direction) of the multiple battery cells 110, and extends in a direction (here, the front-rear direction) perpendicular to the stacking direction. The intermediate plate 12 of the front battery module 11 and the intermediate plate 12 of the rear battery module 11 are provided at positions overlapping each other when viewed from the front-rear direction.

[0019] The intermediate plate 12 is a member having a load-bearing capacity greater than that of the battery cells 110, and is an example of a load-bearing member of the present invention. Each battery module 11 may include a plurality of intermediate plates 12.

[0020] The intermediate plate 12 has bolt holes 121 at both ends in the extending direction (front-rear direction here), through which a bolt B1 can be inserted from above. Each battery module 11 is fixed to the battery case 20 by fastening the bolt B1 inserted through the bolt hole 121 to battery fixing portions N1 and N3 of a cross member 50 and a battery fixing portion N1 of a frame member 40, which will be described later.

[0021] The pair of end plates 13 are provided at both ends in the stacking direction of the multiple battery cells 110, and extend in a direction perpendicular to the stacking direction. The end plate 13 of the front battery module 11 and the end plate 13 of the rear battery module 11 are provided at positions overlapping each other when viewed from the front-rear direction.

[0022] The pair of end plates 13, like the intermediate plate 12, are members having a load-bearing capacity greater than that of the battery cells 110, and are an example of the load-bearing members of the present invention. In this manner, each battery module 11 is provided with a plurality of load-bearing members (i.e., the intermediate plate 12 and the pair of end plates 13) spaced apart from each other in the left-right direction.

[0023] The pair of restraint members 14 face each other in the vertical direction and are connected to the pair of end plates 13 to restrain the multiple battery cells 110. The pair of restraint members 14 have, for example, a plate shape and cover the multiple battery cells 110, the intermediate plate 12, and the pair of end plates 13 from the vertical direction.

[0024] The pair of cover plates 15 are provided outside the multiple battery cells 110 in the front-rear direction and extend in the stacking direction. The cover plate 15 has end plate connecting portions 154 that are provided at a left end portion 15L and a right end portion 15R in the longitudinal direction and connect to the pair of end plates 13.

[0025] Furthermore, bolt holes 158 into which bolts B2 can be inserted from above are provided between the left-right center portion and the left end portion 15L of the cover plate 15, and between the left-right center portion and the right end portion 15R. Each battery module 11 is fixed to the battery case 20 by fastening the bolts B2 inserted through the bolt holes 158 to battery fixing portions N2, N4 of the cross member 50 and the battery fixing portion N2 of the frame member 40, which will be described later.

[0026] (Junction box) Returning to FIG. 2, in the junction box 17, electronic components such as conductive members, fuses, contactors, etc. that connect the power system inside the battery case 20 and the DC line outside the battery case 20 are arranged.

[0027] The junction box 17 is disposed on an upper surface of an upper frame 19 that extends in the front-rear direction. The upper frame 19 is provided above the four battery modules 11 in the left-right central portion of the battery case 20.

[0028] (Battery ECU) The battery ECU 18 is a control device that controls charging and discharging of the battery module 11, and includes a processor, a memory, an interface, etc. The battery ECU 18 is disposed on the upper surface of the upper frame 19 at a position rearward of the junction box 17.

[0029] (Battery case) The battery case 20 includes a case body 21 and a cover 22 that covers the case body 21 from above.

[0030] The case body 21 has a tray shape, and the battery module 11 is placed thereon. The case body 21 includes a base plate 31, a water jacket plate 32, a frame member 40, and a cross member 50.

[0031] The battery module 11 is placed on the upper surface of the base plate 31. The base plate 31 is a member extending in the horizontal direction, and is formed by pressing a metal material such as aluminum.

[0032] The water jacket plate 32 is joined to the lower surface of the base plate 31. Specifically, the outer edge of the water jacket plate 32 is joined to the lower surface of the base plate 31 by brazing or the like. The water jacket plate 32 is a member extending in the horizontal direction.

[0033] A water jacket 70 is formed between the base plate 31 and the water jacket plate 32. The water jacket 70 and the water jacket plate 32 will be described in detail later.

[0034] The frame member 40 is joined to the outer edge of the base plate 31 and constitutes the outer frame (i.e., the rear wall, the front wall, the left wall, and the right wall) of the case body 21. The frame member 40 is, for example, an aluminum casting material. Note that, in this embodiment, the base plate 31 and the frame member 40 are constituted by separate members, but this is not limited thereto, and the base plate 31 and the frame member 40 may be formed integrally.

[0035] The frame member 40 has a rear frame 41 provided on the rear edge of the base plate 31, a front frame 42 provided on the front edge of the base plate 31, and a pair of side frames 43, 44 (also referred to as the left side frame 43 and the right side frame 44, respectively) provided on the left and right edges of the base plate 31. The rear frame 41 and the front frame 42 extend in the left-right direction, and the pair of side frames 43, 44 extend in the front-rear direction. The rear frame 41 and the front frame 42 are connected to the pair of side frames 43, 44 by welding or the like.

[0036] The rear frame 41 and the front frame 42 are provided with battery fixing parts N1 and N2 that fix the battery module 11 to the battery case 20. Note that in FIG. 2, the battery fixing parts N1 and N2 provided on the front frame 42 are omitted from illustration.

[0037] The cross member 50 extends in the left-right direction inside the battery case 20. The cross member 50 is provided in the center of the battery case 20 in the front-rear direction, and is disposed between the two battery modules 11 arranged on the front side and the two battery modules 11 arranged on the rear side. The cross member 50, together with the rear frame 41 and the front frame 42, supports a load input from the side of the battery pack 10 due to a collision, and protects the battery modules 11 placed inside the battery case 20.

[0038] Fig. 5 is an enlarged perspective view of the cross member 50. Fig. 6 is a top view showing the positional relationship between the cross member 50 and the front and rear battery modules 11. Fig. 7 is a cross-sectional view taken along line AA in Fig. 6. Fig. 8 is a cross-sectional view taken along line BB in Fig. 6.

[0039] The cross member 50 has a lower cross member 51, an upper cross member 52, and a plurality of (in this embodiment, five) bolt fixing portions 53 that fix the lower cross member 51 and the upper cross member 52 to each other with bolts B3.

[0040] The lower cross member 51 is provided in contact with the base plate 31, and extends in the left-right direction between the pair of side frames 43, 44. The lower cross member 51 is disposed below the upper cross member 52 in a position overlapping with the upper cross member 52 when viewed in the up-down direction. The lower cross member 51 is joined to the base plate 31 and the pair of side frames 43, 44.

[0041] The lower cross member 51 has a battery fixing portion N1 that fastens with a bolt B1 inserted into a bolt hole 121 of the intermediate plate 12 of each battery module 11, and a battery fixing portion N2 that fastens with a bolt B2 inserted into a bolt hole 158 of the cover plate 15 of each battery module 11. The battery fixing portions N1, N2 are provided on the front and rear sides of the lower cross member 51.

[0042] The upper cross member 52 is attached to the upper side of the lower cross member 51. The upper cross member 52 has a battery fixing portion N3 that fastens with a bolt B1 inserted into a bolt hole 121 of the intermediate plate 12 of each battery module 11, and a battery fixing portion N4 that fastens with a bolt B2 inserted into a bolt hole 158 of the cover plate 15 of each battery module 11. The battery fixing portions N3 and N4 are provided on the front and rear sides of the upper cross member 52.

[0043] The battery fixing portion N1 of the lower cross member 51, the battery fixing portion N3 of the upper cross member 52, and the bolt hole 121 of the intermediate plate 12 are located in overlapping positions when viewed from the vertical direction, and the battery module 11 is fixed to the battery case 20 by inserting a bolt B1 through these and fastening them.

[0044] Similarly, the battery fixing portion N2 of the lower cross member 51, the battery fixing portion N4 of the upper cross member 52, and the bolt hole 158 of the cover plate 15 are located in overlapping positions when viewed from the vertical direction, and the battery module 11 is fixed to the battery case 20 by inserting and fastening bolt B2 through these.

[0045] The battery fixing parts N1 and N3 are provided at positions overlapping the bolt fixing parts 53 when viewed from the front-rear direction. The battery fixing parts N2 and N4 are provided between the bolt fixing parts 53 adjacent to each other.

[0046] In this embodiment, the battery module 11 is fixed to both the lower cross member 51 and the upper cross member 52, but this is not limited thereto, and the battery module 11 may be configured to be fixed to only one of the lower cross member 51 and the upper cross member 52. In other words, the battery fixing portions N1, N2 of the lower cross member 51 may not be provided, or the battery fixing portions N3, N4 of the upper cross member 52 may not be provided.

[0047] Furthermore, the upper frame 19 described above is attached to the center of the upper cross member 52 in the left-right direction.

[0048] The lower cross member 51 and the upper cross member 52 are disposed at a distance from each other at a position between adjacent bolt fixing portions 53, and a lightening portion 54 is formed between the lower cross member 51 and the upper cross member 52. This makes it possible to reduce the weight of the battery pack 10. In addition, since the cross member 50 is configured to have the lower cross member 51 and the upper cross member 52, the lightening portion 54 can be formed more easily than when lightening is performed on a cross member configured from a single member.

[0049] The multiple bolt fixing portions 53 are arranged side by side in the direction in which the cross member 50 extends (the left-right direction). Each bolt fixing portion 53 is a portion of the battery case 20 that has a large load-bearing capacity. The number of bolt fixing portions 53 is arbitrary.

[0050] Each bolt fixing portion 53 is disposed at a position overlapping with the intermediate plate 12 or the end plate 13 of the front and rear battery modules 11 when viewed from the front-rear direction.

[0051] 7, each bolt fixing portion 53 has a bolt hole 51a provided in the lower cross member 51 and a bolt hole 52a provided in the upper cross member 52. The bolt hole 51a of the lower cross member 51 and the bolt hole 52a of the upper cross member 52 are arranged in a position where they overlap when viewed from the up-down direction. For example, a female thread is formed in the bolt hole 51a of the lower cross member 51, and each bolt fixing portion 53 fixes the lower cross member 51 and the upper cross member 52 to each other by, for example, fastening a bolt B3 inserted through the bolt holes 51a, 52a from above the upper cross member 52 to the bolt hole 51a.

[0052] Further, each bolt fixing portion 53 is provided around the bolt hole 51 a of the lower cross member 51 in contact with the base plate 31 of the case body 21 .

[0053] 7 and 8, each bolt fixing portion 53 (excluding the central bolt fixing portion 53 in the left-right direction) fixes the lower cross member 51 and the upper cross member 52 to the floor panel 3. Specifically, each bolt fixing portion 53 fixes the lower cross member 51 and the upper cross member 52 to the floor panel 3 by inserting the bolt B3 through the bolt hole 4 provided in the floor panel 3 and also through the bolt hole 22a provided in the cover 22, and fastening the bolt B3 to the bolt hole 51a of the lower cross member 51.

[0054] Meanwhile, a bolt fixing portion 53 in the center in the left-right direction fixes the upper frame 19 to the upper cross member 52 by inserting a bolt B3 into a bolt hole 19a (see FIG. 8) formed in the upper frame 19.

[0055] Here, each bolt fixing portion 53 (excluding the central bolt fixing portion 53 in the left-right direction) will be described in detail. The bolt B3 has a lower bolt B3a and an upper bolt B3b. The lower bolt B3a has a male thread formed at the tip (lower end) of the threaded portion for fastening with the bolt hole 51a, and a female thread formed at the head (upper end) for fastening with the upper bolt B3b.

[0056] The male thread of the lower bolt B3a is fastened to the bolt hole 51a, whereby the lower cross member 51 and the upper cross member 52 are fixed to each other.

[0057] In addition, a portion of the head of the lower bolt B3a is exposed from the bolt hole 22a of the cover 22, and the upper bolt B3b is fastened to the female thread formed on the head of the lower bolt B3a from above the bolt hole 4 of the floor panel 3, thereby fixing the lower cross member 51 and the upper cross member 52 to the floor panel 3.

[0058] Returning to Fig. 2, a heat insulating material 34 made of, for example, foamed polypropylene is attached to the battery case 20 from below, covering the water jacket 70 from below. Furthermore, a lower cover 35 is attached to the battery case 20 from below the heat insulating material 34. The lower cover 35 is made of a lightweight material such as resin. Note that the heat insulating material 34 and the lower cover 35 are omitted from illustrations other than Fig. 2.

[0059] The cover 22 is attached to the frame member 40 from above. A seal member 23 (e.g., rubber foam; see Figs. 11 and 12) is provided between the upper surface of the frame member 40 and the outer edge of the cover 22, and the inside of the battery case 20 is sealed by attaching the cover 22 to the upper surface of the frame member 40. The cover 22 is attached to the frame member 40 by, for example, bolts (not shown). Here, with the cover 22 attached, the side of the seal member 23 facing the battery module 11 is the inside of the battery case 20, and the side of the seal member 23 opposite the battery module 11 is the outside of the battery case 20.

[0060] (Water jacket) Fig. 9 is a top view of the battery pack 10 with the cover 22 removed. In Fig. 9, a protrusion 320, which will be described later, is indicated by a dashed line. Fig. 10 is a bottom view of the battery pack 10. In Fig. 10, a water jacket 70 is indicated by a dashed line. The cross section of the water jacket 70 will be described with reference to Fig. 8 mentioned above.

[0061] 2 and 8, the water jacket 70 is configured with flow paths defined by the base plate 31 and the water jacket plate 32, and a coolant (e.g., cooling water) flows inside the water jacket 70 to cool the battery module 11. In this embodiment, the flow paths of the water jacket 70 are defined by providing irregularities in the water jacket plate 32, but the present invention is not limited to this. The base plate 31 may have irregularities, or both the base plate 31 and the water jacket plate 32 may have irregularities.

[0062] 10, in this embodiment, the water jacket 70 has a left water jacket 70L provided on the left side of the battery case 20, and a right water jacket 70R provided on the right side of the battery case 20. The left water jacket 70L and the right water jacket 70R have bilaterally symmetrical shapes.

[0063] A supply port 70a and a discharge port 70b are provided at the front end of each of the water jackets 70L and 70R. Hoses (not shown) are connected to the supply port 70a and the discharge port 70b, and the refrigerant is supplied to each of the water jackets 70L and 70R from the supply port 70a and discharged to the outside from the discharge port 70b.

[0064] Each of the water jackets 70L and 70R has a plurality of flow passages 71, 73, 75, and 77 extending in the front-rear direction and a plurality of flow passages 72, 74, and 76 extending in the left-right direction. The flow passage 71 has a supply port 70a at the front end and extends from the supply port 70a along the left edge or the right edge of the water jacket plate 32. The flow passage 73 extends in the center of the water jacket plate 32 of the flow passage 71. The flow passage 71 and the flow passage 73 are connected by the flow passage 72 at the rear end. The flow passage 75 and the flow passage 77 are provided between the flow passage 71 and the flow passage 73, the flow passage 75 is provided next to the flow passage 73, and the flow passage 77 is provided next to the flow passage 71. The flow passage 73 and the flow passage 75 are connected by the flow passage 74 at the front end. The flow passage 75 and the flow passage 77 are connected by the flow passage 76 at the rear end. The flow passage 77 has an outlet 70b at the front end.

[0065] (Protruding part on the bottom of the battery case) A plurality of protruding portions 320 protruding downward are provided on the bottom surface of the battery case 20, i.e., the water jacket plate 32. The plurality of protruding portions 320 are integrally provided on the water jacket plate 32. The plurality of protruding portions 320 will be described below with reference to Figs. 8 to 13.

[0066] As shown in Figures 9 and 10, the protrusion 320 includes a first protrusion 321 extending continuously in the front-to-rear direction, a second protrusion 325 provided at the front end of the water jacket plate 32, and a third protrusion 327 provided at the rear end of the water jacket plate 32.

[0067] The protrusions 320 (i.e., the first protrusion 321, the second protrusion 325, and the third protrusion 327) protrude downward below the water jacket 70 (see FIG. 8). Therefore, for example, when an object such as a curb collides with the battery pack 10 from below and a load is input, the load is input to the protrusions 320 before being input to the water jacket 70. This makes it possible to protect the water jacket 70. Note that the protrusions 320 may be configured to have the same protrusion amount as the water jacket 70, that is, the lower end position of the protrusions 320 may coincide with the lower end position of the water jacket 70 in the up-down direction.

[0068] A plurality of first protrusions 321 (five in this embodiment) are arranged in the left-right direction. The front end of each first protrusion 321 is located forward of the cross member 50, and the rear end is located rearward of the cross member 50. Each first protrusion 321 is arranged so as to intersect with the cross member 50 when viewed from the top-bottom direction. In this embodiment, each first protrusion 321 is arranged linearly in the front-rear direction when viewed from the top-bottom direction, but is not limited to this and may be arranged in a curved shape (for example, a wave shape) when viewed from the top-bottom direction.

[0069] When viewed from the top-bottom direction, each of the first protrusions 321 intersects with the cross member 50 at a position overlapping with the bolt fixing portion 53 of the cross member 50. The bolt fixing portion 53 is a portion of the battery case 20 that has a large load-bearing capacity. In other words, when viewed from the top-bottom direction, each of the first protrusions 321 intersects with the cross member 50 at a position overlapping with a portion that has a large load-bearing capacity.

[0070] When an object such as a curb hits the battery pack 10 from below, the load is input to the first protrusion 321 protruding downward from the bottom surface of the battery case 20. The load received by the first protrusion 321 is supported by the bolt fixing portion 53 and the lower cross member 51 and the upper cross member 52 fixed by the bolt fixing portion 53. Therefore, the battery module 11 can be protected from the load input from below the battery pack 10.

[0071] In addition, since the first protrusion 321 is provided integrally with the water jacket plate 32, it is not necessary to provide, for example, a high-strength metal protective plate below the water jacket plate 32 to protect the battery module 11 and the water jacket 70, and the number of parts can be reduced. In addition, it is not necessary to form the base plate 31 and the water jacket plate 32 thick, or to make the resin lower cover 35 out of a high-strength metal, and it is possible to reduce the weight. In this way, it is possible to protect the battery module 11 while reducing the number of parts and the weight of the battery pack 10.

[0072] Furthermore, as mentioned above, the bolt fixing portion 53 fixes the lower cross member 51 and the upper cross member 52 to the floor panel 3, so that the load received by the first protrusion portion 321 due to a collision of an object from below can be supported not only by the bolt fixing portion 53, the lower cross member 51, and the upper cross member 52, but also by the floor panel 3.

[0073] As described above, the lower cross member 51 and the upper cross member 52 are fixed at the battery fixing parts N1, N3 to the intermediate plate 12, which has a large load-bearing capacity among the battery modules 11. This allows the load received by the first protrusion 321 due to a collision of an object from below to be transmitted to the intermediate plate 12 via the bolt fixing part 53, the lower cross member 51, and the upper cross member 52. This allows the load-bearing capacity of the bolt fixing part 53, the lower cross member 51, and the upper cross member 52 to be increased.

[0074] As described above, the battery fixing parts N1, N3 which are the fixing parts between the lower cross member 51 and the upper cross member 52 and the intermediate plate 12 are provided at positions overlapping with the bolt fixing part 53 of the cross member 50 when viewed from the front-rear direction. This shortens the load transmission path from the bolt fixing part 53 to the intermediate plate 12, so that the load received by the first protruding part 321 due to the collision of an object from below can be transmitted to the intermediate plate 12 more efficiently.

[0075] Here, the first protrusions 321 will be described in detail. The five first protrusions 321 include two first protrusions 321a provided at positions overlapping with the intermediate plates 12 of the two battery modules 11 arranged side by side in the front-rear direction when viewed from the top-bottom direction, and three first protrusions 321b provided at positions overlapping with the end plates 13 of the two battery modules 11 arranged side by side in the front-rear direction.

[0076] Since each first protrusion 321a is disposed directly below the intermediate plate 12 of the battery module 11, even if an upward load is applied to the first protrusion 321a, the load can be received by the intermediate plate 12, which has a large load resistance. Therefore, the battery cells 110 can be protected.

[0077] The length of each first protrusion 321a in the front-rear direction is longer than the length of the intermediate plate 12 of each battery module 11 in the front-rear direction, and each first protrusion 321a is provided below the intermediate plate 12 of the front battery module 11 and the intermediate plate 12 of the rear battery module 11. Therefore, when a load input from below the battery pack 10 is received by the first protrusion 321a, the load can be distributed in the front-rear direction and received by the intermediate plate 12.

[0078] Since each first protrusion 321b is disposed directly below the end plate 13 of the battery module 11, even when an upward load is applied to the first protrusion 321b, the load can be received by the end plate 13, which has a large load resistance. Therefore, the battery cell 110 can be protected.

[0079] The length of each first protrusion 321b in the front-rear direction is longer than the length of the end plate 13 of each battery module 11 in the front-rear direction, and each first protrusion 321b is provided below the end plate 13 of the front battery module 11 and the end plate 13 of the rear battery module 11. Therefore, when a load input from below the battery pack 10 is received by the first protrusion 321b, the load can be distributed in the front-rear direction and received by the end plate 13.

[0080] Each of the multiple first protrusions 321 is positioned at a position that overlaps with the corresponding intermediate plate 12 or end plate 13 when viewed from the top-bottom direction, so that regardless of the position in the left-right direction, the load input from below the battery pack 10 can be received by the multiple first protrusions 321 and supported by the intermediate plate 12 and / or end plate 13.

[0081] The second protrusion 325 extends in the left-right direction and is provided at the front end of the water jacket plate 32. As described above, the supply port 70a and the discharge port 70b are provided at the front end of each of the water jackets 70L, 70R, and the second protrusion 325 is provided discontinuously near the supply port 70a and the discharge port 70b.

[0082] Fig. 11 shows a cross-sectional view taken along line CC in Fig. 9. The second protrusion 325 is provided at a position overlapping with the front frame 42 when viewed from the top-bottom direction. With this configuration, the load input from below the battery pack 10 and received by the second protrusion 325 can be further supported by the front frame 42.

[0083] The front ends of the base plate 31 and the water jacket plate 32 have a front crash stroke portion S1 that extends further outward (forward here) from the second protrusion 325 of the battery case 20. When a horizontal load is applied from the front of the battery pack 10, the base plate 31 and the water jacket plate 32 support a relatively small load, and the front crash stroke portion S1 deforms to absorb a relatively large load. This protects the battery module 11 arranged inside the battery case 20.

[0084] 9 and 10, the third protrusion 327 is provided on the rear end of the water jacket plate 32, and is composed of a plurality of protrusions 327a protruding downward. The plurality of protrusions 327a are arranged side by side in the left-right direction, and adjacent protrusions 327a are arranged at a predetermined interval.

[0085] Fig. 12 shows a cross-sectional view taken along line DD in Fig. 9. The rear end portions of the base plate 31 and the water jacket plate 32 have a rear crash stroke portion S2 that extends further outward (rearward in this case) from the third protrusion 327 toward the outside of the battery case 20. When a horizontal load is applied from the rear of the battery pack 10, the base plate 31 and the water jacket plate 32 support a relatively small load, and the rear crash stroke portion S2 deforms to absorb a relatively large load. This protects the battery module 11 arranged inside the battery case 20.

[0086] Since the third protrusion 327 is composed of a plurality of protrusions 327a, the horizontal portions between the adjacent protrusions 327a can also withstand a horizontal load from the rear. This improves the horizontal load resistance of the rear ends of the base plate 31 and the water jacket plate 32.

[0087] In this embodiment, the third protrusion 327 is provided between the rear frame 41 and the water jacket 70 in the front-rear direction.

[0088] FIG. 13 shows the present embodiment (upper part) in which the third protrusion 327 is provided between the water jacket 70 and the rear frame 41, and a comparative example (lower part) in which the third protrusion 327 is provided immediately below the rear frame 41. In the comparative example, the presence of the third protrusion 327 provided immediately below the rear frame 41 and the rear crush stroke portion S2 lengthens the outer portion of the battery case 20 (i.e., the rear side of the seal member 23). On the other hand, in the present embodiment, the third protrusion 327 is not provided immediately below the rear frame 41, so that the portion of the rear crush stroke portion S2 that is located outside the battery case 20 can be shortened. Therefore, the battery pack 10 can be made compact in the front-rear direction.

[0089] Although one embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. In addition, the components in the above embodiment may be arbitrarily combined within the scope of the invention.

[0090] For example, in the above-described embodiment, the cross member 50 is fixed to the intermediate plate 12, which is an example of a load-bearing member, but this is not limited to this. For example, instead of or in addition to fixing the cross member 50 to the intermediate plate 12, a fixing portion for the cross member 50 may be provided on the end plate 13, which is another example of a load-bearing member, and the cross member 50 and the end plate 13 may be fixed thereto.

[0091] In the above-described embodiment, the second protruding portion 325 is provided at a position overlapping with the front frame 42 when viewed from the top-bottom direction, but this is not limited to this. For example, similar to the third protruding portion 327, the second protruding portion 325 may be provided between the water jacket 70 and the front frame 42 when viewed from the top-bottom direction. Similarly to the third protruding portion 327, the second protruding portion 325 may be formed of a plurality of protrusions arranged side by side in the left-right direction.

[0092] In the above-described embodiment, the third protruding portion 327 is provided between the water jacket 70 and the rear frame 41 when viewed from the top-bottom direction, but this is not limited to this. For example, similar to the second protruding portion 325, the third protruding portion 327 may be provided between the water jacket 70 and the rear frame 41 when viewed from the top-bottom direction.

[0093] This specification describes at least the following items. In parentheses, components corresponding to the above-described embodiment are shown as examples, but the present invention is not limited to these.

[0094] (1) A battery pack (battery pack 10) that is mounted under a floor of a vehicle body (vehicle body 1), A battery module (battery module 11) including a plurality of battery cells (battery cells 110) stacked in a first direction (left-right direction) among horizontal directions, and at least two battery modules (battery modules 11) arranged side by side in a second direction (front-rear direction) among the horizontal directions perpendicular to the first direction; A case (battery case 20) that houses the battery module, The case is A case body (case body 21) on which the battery module is placed; a cross member (cross member 50) extending in the first direction inside the case and provided between the at least two battery modules arranged side by side in the second direction; The cross member is An upper cross member (upper cross member 52); A lower cross member (lower cross member 51) is arranged below the upper cross member in a position overlapping the upper cross member when viewed from the up-down direction; a fixing portion (bolt fixing portion 53) that abuts against a bottom surface of the case body and fixes the upper cross member and the lower cross member to each other with a fastening member (bolt B3), At least one first protrusion (first protrusion 321) is integrally provided on the bottom surface of the case body, protruding downward and continuously extending in the second direction, The first protrusion intersects with the cross member at a position overlapping with the fixing portion of the cross member when viewed from the up-down direction. Battery pack.

[0095] According to (1), the first protrusion provided on the bottom surface of the case intersects with the cross member at a position overlapping with the fixed portion of the cross member when viewed from the top-bottom direction, so that the load input from below the battery pack and received by the first protrusion can be supported by the fixed portion, the upper cross member, and the lower cross member. Therefore, the battery module can be protected from the load input from below the battery pack. In addition, since the first protrusion is integrally provided on the bottom surface of the case body, it is possible to protect the battery module while reducing the number of parts and weight.

[0096] In the above-described embodiment, the first direction is the left-right direction and the second direction is the front-rear direction, but the first direction may be the front-rear direction and the second direction may be the left-right direction.

[0097] (2) A battery pack according to (1), The fixing portion of the cross member fixes the upper cross member and the lower cross member to a floor panel (floor panel 3). Battery pack.

[0098] According to (2), the load input from below the battery pack and received by the first protruding portion can be further supported by the floor panel.

[0099] (3) A battery pack according to (1) or (2), Each battery module has a load-bearing member (an intermediate plate 12, an end plate 13) that extends in the second direction and has a load-bearing capacity larger than that of the battery cell, At least one of the upper cross member and the lower cross member is fixed to the load-bearing member. Battery pack.

[0100] According to (3), the load input from below the battery pack and received by the first protrusion can be transmitted to the load-bearing member of the battery module via the fixed portion of the cross member and at least one of the upper cross member and the lower cross member.

[0101] (4) A battery pack according to (3), A fixing portion (battery fixing portion N1, N3) between at least one of the upper cross member and the lower cross member and the load-bearing member is provided at a position overlapping with the fixing portion of the cross member when viewed from the second direction. Battery pack.

[0102] According to (4), the load transmission path from the fixed portion of the cross member to the load-bearing member of the battery module is shortened, so that the load input from below the battery pack and received by the first protrusion can be transmitted to the load-bearing member more efficiently.

[0103] (5) A battery pack according to any one of (1) to (4), Further comprising a water jacket (water jacket 70) through which a refrigerant for cooling the battery module flows, The case body includes: A base plate (base plate 31) on which the battery module is mounted; a water jacket plate (water jacket plate 32) joined to a lower surface of the base plate and forming the water jacket between the base plate and the water jacket; a frame member (frame member 40) joined to an outer edge portion of the base plate and constituting an outer frame of the case, A second protruding portion (second protruding portion 325) extending in the first direction is provided on the lower surface of the water jacket plate, The second protrusion is The water jacket is provided with a lower end portion, and the lower end portion protrudes downward from the water jacket or protrudes to a lower end position of the water jacket in the vertical direction. The support is provided at a position overlapping with the frame member when viewed from the up-down direction. Battery pack.

[0104] According to (5), when a load is input from below the battery pack, the load is received by the second protrusion, so that the water jacket can be protected. Also, since the second protrusion is disposed at a position overlapping with the frame member when viewed from the top-bottom direction, the load input from below the battery pack and received by the second protrusion can be supported by the frame member.

[0105] (6) A battery pack according to any one of (1) to (5), Further comprising a water jacket (water jacket 70) through which a refrigerant for cooling the battery module flows, The case body includes: A base plate (base plate 31) on which the battery module is mounted; a water jacket plate (water jacket plate 32) joined to a lower surface of the base plate and forming the water jacket between the base plate and the water jacket; a frame member (frame member 40) joined to an outer edge portion of the base plate and constituting an outer frame of the case, A third protruding portion (third protruding portion 327) protruding downward is provided on the lower surface of the water jacket plate, The third protrusion is The water jacket is provided with a lower end portion, and the lower end portion protrudes downward from the water jacket or protrudes to a lower end position of the water jacket in the vertical direction. The protrusions are arranged in the first direction. Battery pack.

[0106] According to (6), when a load is input from below the battery pack, the load is received by the third protrusion, so that the water jacket can be protected. Also, since the third protrusion is composed of a plurality of protrusions arranged side by side, the portion between the adjacent protrusions can receive the load in a direction parallel to the base plate and the water jacket plate.

[0107] (7) A battery pack according to (6), The plurality of protrusions are provided between the frame member and the water jacket in the second direction. Battery pack.

[0108] According to (7), the crash stroke portion from the tip end of the base plate and the water jacket plate to the multiple protrusions does not need to extend far outside the case, so that the battery pack can be made compact.

[0109] (8) A battery pack according to any one of (1) to (7), Each battery module has at least one load-bearing member (an intermediate plate 12, an end plate 13) extending in the second direction and having a load-bearing capacity greater than that of the battery cell; the load-bearing members of the at least two battery modules arranged side by side in the second direction are arranged in positions overlapping each other when viewed from the second direction, the first protrusion is provided at a position overlapping with the load-bearing members of the at least two battery modules arranged side by side in the second direction when viewed from the up-down direction, The length of the first protrusion in the second direction is longer than the length of the load-bearing member of each battery module in the second direction. Battery pack.

[0110] According to (8), the load input from below the battery pack and received by the first protrusion can be supported by the load-bearing member of the battery module. In addition, since the length of the first protrusion in the second direction is longer than the length of the load-bearing member of each battery module in the second direction, the load received by the first protrusion can be dispersed in the second direction, and even if a larger load is input, it can be supported by the load-bearing member.

[0111] (9) The battery pack according to (8), The load-bearing members are provided in a plurality of positions spaced apart from each other in the first direction in each battery module, The first protrusion is provided on a bottom surface of the case and is aligned in the first direction. Each of the first protrusions (first protrusions 321a, 321b) is provided at a position overlapping the corresponding load-bearing member when viewed from the up-down direction. Battery pack.

[0112] According to (9), a plurality of first protrusions are provided in the first direction and are positioned so as to overlap with corresponding load-bearing members, so that the first protrusions can support the load input from below the battery pack regardless of the position in the first direction. [Explanation of symbols]

[0113] 1. Vehicle body 3 Floor Panel 10 Battery pack 11 Battery Module 12 Intermediate plate (load-bearing member) 13 End plate (load-bearing member) 20 Battery case (case) 21 Case body 31 Base Plate 32 Water jacket plate 40 Frame members 50 Cross member 51 Lower cross member 52 Upper cross member 53 Bolt fixing part (fixing part) 70 Water Jacket 110 Battery Cell 321 1st protrusion 321a 1st protrusion 321b 1st protrusion 325 Second protrusion 327 Third protrusion 327a protrusion B3 Bolt (fastening member) N1 Battery fixing part (fixing part) N3 Battery fixing part (fixing part)

Claims

1. A battery pack that is mounted under the floor of a vehicle body, a battery module including a plurality of battery cells stacked in a first direction among horizontal directions, and at least two battery modules arranged side by side in a second direction among the horizontal directions perpendicular to the first direction; A case that houses the battery module, The case is a case body on which the battery module is placed; a cross member extending in the first direction inside the case and provided between the at least two battery modules arranged side by side in the second direction; The cross member is The upper cross member, A lower cross member is disposed below the upper cross member in a position overlapping the upper cross member when viewed from the up-down direction; a fastening portion that abuts against a bottom surface of the case body and fastens the upper cross member and the lower cross member to each other with a fastening member; At least one first protrusion is integrally provided on a bottom surface of the case body, protruding downward and continuously extending in the second direction, The first protrusion portion intersects with the cross member at a position overlapping with the fixing portion of the cross member when viewed from the up-down direction. Battery pack.

2. 2. The battery pack according to claim 1, The fixing portion of the cross member fixes the upper cross member and the lower cross member to a floor panel. Battery pack.

3. 3. The battery pack according to claim 1, Each battery module includes a load-bearing member extending in the second direction and having a load-bearing capacity greater than that of the battery cell, At least one of the upper cross member and the lower cross member is fixed to the load-bearing member. Battery pack.

4. 4. The battery pack according to claim 3, A fixing portion between at least one of the upper cross member and the lower cross member and the load-bearing member is provided at a position overlapping with the fixing portion of the cross member when viewed from the second direction. Battery pack.

5. 3. The battery pack according to claim 1, A water jacket through which a refrigerant for cooling the battery module flows is further provided, The case body includes: A base plate on which the battery module is mounted; a water jacket plate joined to a lower surface of the base plate to form the water jacket between the base plate and the water jacket plate; a frame member joined to an outer edge portion of the base plate and constituting an outer frame of the case, A second protruding portion extending in the first direction is provided on a lower surface of the water jacket plate, The second protrusion is The water jacket is provided with a lower end portion, and the lower end portion protrudes downward from the water jacket or protrudes to a lower end position of the water jacket in the vertical direction. The support is provided at a position overlapping with the frame member when viewed from the up-down direction. Battery pack.

6. 3. The battery pack according to claim 1, A water jacket through which a refrigerant for cooling the battery module flows is further provided, The case body includes: A base plate on which the battery module is mounted; a water jacket plate joined to a lower surface of the base plate to form the water jacket between the base plate and the water jacket; a frame member joined to an outer edge portion of the base plate and constituting an outer frame of the case, A third protruding portion protruding downward is provided on the lower surface of the water jacket plate, The third protrusion is The water jacket is provided with a lower end portion, and the lower end portion protrudes downward from the water jacket or protrudes to a lower end position of the water jacket in the vertical direction. The projections are arranged in the first direction. Battery pack.

7. 7. The battery pack according to claim 6, The plurality of protrusions are provided between the frame member and the water jacket in the second direction. Battery pack.

8. 3. The battery pack according to claim 1, Each battery module includes at least one load-bearing member extending in the second direction and having a load-bearing capacity greater than that of the battery cell; The load-bearing members of the at least two battery modules arranged side by side in the second direction are arranged in positions overlapping each other when viewed from the second direction, The first protrusion is provided at a position overlapping with the load-bearing members of the at least two battery modules arranged side by side in the second direction when viewed from the up-down direction, A length of the first protrusion in the second direction is longer than a length of the load-bearing member of each battery module in the second direction. Battery pack.

9. 9. The battery pack according to claim 8, The load-bearing members are provided in a plurality of positions spaced apart from each other in the first direction in each battery module, The first protrusion is provided on a bottom surface of the case in a plurality of positions aligned in the first direction, Each of the first protrusions is provided at a position overlapping with a corresponding one of the load-bearing members when viewed from the up-down direction. Battery pack.

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