Battery mounting structure in vehicle

Abstract

The invention relates to a battery mounting structure in a vehicle. A battery mounting structure in a vehicle is provided with: a battery laminate configured by laminating a plurality of square batteries in the thickness direction of the square batteries; a lower case having an opening on the upper surface thereof; an upper case, which is attached to the upper part of the lower case so as to close the opening, and which has an open lower surface; a fastening member that fastens the lower case and the upper case such that a force in the thickness direction is applied to the battery stack from the lower case and the upper case; and a cross member that is a part of a vehicle body frame member that supports the lower case and the upper case, extends in the vehicle width direction, and the lower surface of the cross member applies a force in the thickness direction to the upper surface of the upper case.

Description

Technical Field

[0001] This invention relates to a battery mounting structure in a vehicle. Background Technology

[0002] The following battery module is disclosed in Japanese Patent Application Publication No. 2021-140874: In order to suppress the deviation of the pressure applied to the multiple secondary batteries constituting the battery stack, a spacer is provided between the housing housing the battery stack and the battery stack. Summary of the Invention

[0003] In recent years, there has been a demand for higher energy density in battery modules. However, to increase the energy density of battery modules, it is necessary to reduce the space occupied by components other than the battery stack within the casing. That is, if spacers are installed inside the battery casing as in Japanese Patent Application Publication No. 2021-140874, it is difficult to increase the energy density of the battery module.

[0004] In view of the above facts, the object of the present invention is to obtain a battery mounting structure in a vehicle that can easily improve the energy density of a battery module having a housing and a battery pack.

[0005] The battery mounting structure in the vehicle according to the first embodiment includes: a battery stack, which is formed by stacking a plurality of rectangular batteries with terminals provided on both ends in the longitudinal direction and in a cuboid shape along the thickness direction of the rectangular batteries; a lower housing, which has an opening on its upper surface and houses the battery stack in such a way that the thickness direction is consistent with the vertical direction; an upper housing, which is mounted on the upper part of the lower housing to block the opening and has an opening on its lower surface; a fastening member, which fastens the lower housing and the upper housing by applying a force in the thickness direction from the lower housing and the upper housing to the battery stack; and a crossbeam, which is part of a vehicle frame member that supports the lower housing and the upper housing, extends in the vehicle width direction, and the lower surface of the crossbeam applies a force in the thickness direction to the upper surface of the upper housing.

[0006] The battery mounting structure in the vehicle according to the first embodiment includes a battery stack, which is constructed by stacking multiple rectangular batteries, each with terminals at both ends in the longitudinal direction and in a cuboid shape, along the thickness direction of the rectangular batteries. The lower housing houses the battery stack in a manner where the thickness direction aligns with the vertical direction. Furthermore, when the lower and upper housings are fastened together by fastening members, a force in the thickness direction of the rectangular batteries is applied to the battery stack from both the lower and upper housings. Additionally, the lower surface of a crossbeam extending along the vehicle width direction applies a force in the thickness direction of the rectangular batteries to the upper surface of the upper housing. Therefore, the battery mounting structure in the vehicle according to the first embodiment can apply pressure in the thickness direction of the rectangular batteries to each battery without the need for spacers. Thus, the battery mounting structure in the vehicle according to the first embodiment easily increases the energy density of the battery module having a lower housing, an upper housing, and a battery stack.

[0007] In the second embodiment of the battery mounting structure in the vehicle, in the first embodiment, the battery stack has a plurality of planar battery cells formed by arranging a plurality of square batteries on a plane orthogonal to the thickness direction, the plurality of planar battery cells being arranged along the thickness direction, and a single cooler is provided in the gap formed between two adjacent planar battery cells, which contacts each of the square batteries constituting the planar battery cells.

[0008] According to the battery mounting structure in the vehicle of the second method, multiple prismatic batteries can be cooled by a small number of coolers.

[0009] In the third type of vehicle battery mounting structure, in the first or second type, the lower surface of the crossbeam contacts the upper surface of the upper housing.

[0010] In a third-party vehicle battery mounting structure, the lower surface of a crossbeam applies pressure along the thickness direction of the prismatic battery to the upper surface of the upper housing. This pressure is applied from the upper housing to the battery stack. Therefore, the third-party vehicle battery mounting structure can utilize the crossbeam to increase the energy density of the battery module.

[0011] As described above, the battery mounting structure in the vehicle of the present invention has the excellent effect of easily improving the energy density of the battery module having a housing and a battery pack. Attached Figure Description

[0012] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, wherein:

[0013] Figure 1 This is a perspective view of the battery mounting structure in the vehicle according to the implementation method.

[0014] Figure 2 It is along Figure 1 A schematic cross-sectional view with arrows 2-2.

[0015] Figure 3 It is a 3D view of a single battery cell.

[0016] Figure 4 This is a top view of the lower casing and the bottommost planar battery cells housed within it.

[0017] Figure 5 It is a schematic cross-sectional view of the lower housing, the upper housing separated from the lower housing, and the battery stack.

[0018] Figure 6 When the lower and upper shells are fixed, Figure 5 The same sectional view. Detailed Implementation

[0019] The battery mounting structure in the vehicle according to the embodiments will now be described with reference to the accompanying drawings. It should be noted that the arrows UP, FR, and LH in the drawings represent the upper side in the vertical direction, the front side in the longitudinal direction, and the left side in the horizontal direction, respectively.

[0020] like Figure 1 as well as Figure 2 As shown, the vehicle 10 employing the battery mounting structure of this embodiment includes: a pair of left and right lower side beams 12, which are part of the vehicle body frame components and extend along the vehicle's longitudinal direction; and a crossbeam 17, which extends along the vehicle's width direction (left-right direction) and is fixed at both ends to the left and right lower side beams 12, and is part of the vehicle body frame components. The lower side beams 12 and the crossbeam 17 are made of metal. Figure 2 As shown, the lower beam 12 has a square cross-section. Multiple through holes 14 are arranged in a front-to-back pattern on the bottom plate 13 of the left and right lower beams 12. Figure 1 (Only one is shown in the figure). Furthermore, on the upper surface of the base plate 13, at positions corresponding to each through hole 14, weld nuts 15 concentric with each through hole 14 are fixed.

[0021] The battery module 20 of this embodiment has a battery housing 22, a battery stack 52, a bolt 75, and a nut 76.

[0022] The battery casing 22 has a lower casing 24 and an upper casing 38. The lower casing 24 and the upper casing 38 are integrally formed metal parts.

[0023] like Figure 1 as well as Figures 4-6As shown, the lower shell 24 is a hollow body with an opening 25 formed on its upper surface. The lower shell 24 has a base plate 26, a front plate 27, a rear plate 28, a pair of side plates 29, and a lower annular flange 30. The base plate 26 is rectangular in plan view, longer in the front-to-back direction than in the left-to-right direction. The lower end of the front plate 27 is fixed to the front edge of the base plate 26, the lower end of the rear plate 28 is fixed to the rear edge of the base plate 26, and the lower ends of the left and right side plates 29 are respectively fixed to the left and right side edges of the base plate 26. Furthermore, the left and right side edges of the front plate 27 are respectively fixed to the front edges of the left and right side plates 29. Similarly, the left and right side edges of the rear plate 28 are respectively fixed to the rear edges of the left and right side plates 29. The left and right side plates 29 are approximately parallel to the vertical direction. However, when viewed from the side, the front plate 27 and the rear plate 28 are inclined relative to the vertical direction. Furthermore, as... Figure 1 as well as Figure 2 As shown, multiple heat dissipation holes 29S are formed as through holes on the front plate portion 27, the rear plate portion 28, and each side plate portion 29. A lower annular flange 30, which appears as a square ring when viewed from above, is fixed to the upper edges of the front plate portion 27, the rear plate portion 28, and the side plate portion 29. Multiple first through holes 34 are formed on the lower annular flange 30, arranged circumferentially. Furthermore, multiple second through holes 35 are formed on the left and right sides of the lower annular flange 30, arranged in the front-rear direction. Multiple weld nuts 76, concentric with each of the first through holes 34, are fixed to the lower surface of the lower annular flange 30.

[0024] like Figure 1 as well as Figures 4-6 As shown, the upper shell 38 is a hollow body with an opening 39 formed on its lower surface. The upper shell 38 has a top plate 40, a front plate 41, a rear plate 42, a pair of side plates 43, and an upper annular flange 44. The top plate 40 has a rectangular shape that is longer in the front-to-back direction than in the left-to-right direction. Figure 5 as well as Figure 6As shown, a plurality of pressing protrusions 40S extending in the front-rear direction are provided on the lower surface of the top plate portion 40. The upper end of the front plate portion 41 is fixed to the front edge of the top plate portion 40, the upper end of the rear plate portion 42 is fixed to the rear edge of the top plate portion 40, and the upper ends of the left and right side plate portions 43 are respectively fixed to the left and right side edges of the top plate portion 40. Furthermore, the left and right side edges of the front plate portion 41 are respectively fixed to the front edges of the left and right side plate portions 43. Furthermore, the left and right side edges of the rear plate portion 42 are respectively fixed to the rear edges of the left and right side plate portions 43. The left and right side plate portions 43 are approximately parallel to the vertical direction. On the other hand, when viewed from the side, the front plate portion 41 and the rear plate portion 42 are inclined relative to the vertical direction. When viewed from above, a square annular upper flange 44 is fixed to the lower edges of the front plate portion 41, the rear plate portion 42, and the side plate portions 43. On the upper annular flange 44, a plurality of first through holes 48 are arranged circumferentially along the upper annular flange 44. Figure 5 , Figure 6 Only the two first through holes 48 are shown in the diagram. Furthermore, as... Figure 1 As shown, multiple second through holes 49 are arranged along the front-back direction on both sides of the upper annular flange 44. The planar shape of the upper annular flange 44 is substantially the same as that of the lower annular flange 30. Furthermore, the number of first through holes 48 is the same as that of first through holes 34, and the number of second through holes 49 is the same as that of second through holes 35.

[0025] like Figure 5 as well as Figure 6 As shown, the battery stack 52 includes multiple battery cells 54, multiple busbars (not shown) and two coolers 72.

[0026] like Figure 3 As shown, the battery cell 54, serving as a secondary battery, is a square battery with a cuboid-shaped main body shell 55, a pair of covers 58, a positive terminal 60, a negative terminal 62, and safety valves 64 and 66. The metal main body shell 55 is a hollow body with openings at both ends along its length (left-right direction). The main body shell 55 has a pair of upper and lower base plates 56 and a pair of side plates 57 connecting the front and rear edges of the upper and lower base plates 56, respectively. The upper and lower base plates 56 are flat plates orthogonal to the vertical direction, and the left and right side plates 57 are flat plates orthogonal to the horizontal direction.

[0027] Metal caps 58 are fixed to the left and right openings of the substrate portion 56, respectively. A positive terminal 60 is provided on one cap 58, and a negative terminal 62 is provided on the other cap 58. Safety valves 64 and 66 are provided on each cap 58. Electrolyte and the like are contained within the internal space of the battery cell 54, which is formed by the main housing 55 and the pair of caps 58. When the pressure in this internal space reaches a predetermined pressure, the safety valves 64 and 66 open, discharging fumes and other contaminants generated inside the internal space to the outside of the battery cell 54.

[0028] like Figures 4-6 As shown, multiple battery cells 54 are electrically connected to each other in an arrangement on an imaginary plane orthogonal to the vertical direction. That is, multiple battery cells 54 are arranged on the imaginary plane with a substrate portion 56 located at the bottom and a pair of cover portions 58 arranged in the horizontal direction. The overall planar shape of the multiple battery cells 54 arranged on the imaginary plane is approximately rectangular, longer in the front-to-back direction than in the horizontal direction. Hereinafter, the multiple battery cells 54 arranged on the imaginary plane will be collectively referred to as a planar battery cell 68. Figure 4 As shown, in this embodiment, four battery cells 54 are arranged in the left-right direction, and ten battery cells 54 are arranged in the front-back direction. That is, the planar battery unit 68 has 40 battery cells 54. Furthermore, as... Figures 4-6 As shown, three linear gaps 69 extending in the front-to-back direction are formed between the cover portions 58 of the battery cells 54 arranged in the left-right direction. Furthermore, the front-to-back dimension of the planar battery cell 68 is slightly shorter than the front-to-back dimension of the pressing protrusion 40S. The positive terminals 60 and negative terminals 62 of the battery cells 54 facing each other in the left-right direction are connected by a metal busbar (not shown). The positive terminals 60 and negative terminals 62 located on the left edge of the planar battery cell 68 and adjacent to each other in the front-to-back direction are connected by a metal busbar (not shown). The positive terminals 60 and negative terminals 62 located on the right edge of the planar battery cell 68 and adjacent to each other in the front-to-back direction are connected by a metal busbar (not shown). In other words, all the battery cells 54 constituting one planar battery cell 68 are electrically connected to each other.

[0029] like Figure 5 as well as Figure 6As shown, the battery module 20 of this embodiment has three planar battery cells 68 with the same structure. Each planar battery cell 68 is electrically connected to the others via a busbar. The three planar battery cells 68 are arranged vertically, and coolers 72 are respectively provided in the gaps 70 formed between adjacent planar battery cells 68. Each cooler 72 is a hollow body whose planar shape is substantially the same as that of the planar battery cell 68, and is made of a metal such as aluminum. Furthermore, each cooler 72 contacts the substrate portion 56 of the main body housing 55 of each battery cell 54 constituting the two planar battery cells 68 located above and below it. One end of a pair of tubes (not shown) is connected to the cooler 72, and the other end of each tube is connected to an electric pump and a heat exchanger on the outside of the battery housing 22. That is, the coolant located inside the pair of tubes and the cooler 72 circulates within the electric pump, heat exchanger, pair of tubes, and cooler 72 by the force generated by the electric pump.

[0030] like Figure 5 As shown, the battery stack 52 of the structure described above is disposed within the interior space of the lower housing 24 in a state separated from the upper housing 38, and is placed on the lower surface of the base plate 26. Furthermore, as... Figure 4 As shown, the front end of the battery stack 52 extends rearward from the front panel 27, and the rear end of the battery stack 52 extends forward from the rear panel 28. Furthermore, as... Figures 4-6 As shown, the left end of the battery stack 52 extends to the right from the left side plate portion 29, and the right end of the battery stack 52 extends to the left from the right side plate portion 29. Furthermore, as... Figure 5 As shown, the upper end of the battery stack 52 is located above the upper end of the lower housing 24.

[0031] And, as Figure 5 As shown, an upper housing 38 covers the upper part of the lower housing 24, which houses the battery stack 52. Although the illustration is omitted, each pressing protrusion 40S of the upper housing 38 contacts the upper surface of the main housing 55 of each battery cell 54 of the uppermost planar battery cell 68 constituting the battery stack 52, and the upper annular flange 44 forms a small gap with respect to the lower annular flange 30 and faces each other from above.

[0032] And, as Figure 6As shown, a downward force is applied to the upper housing 38, causing the upper annular flange 44 to contact the lower annular flange 30 of the lower housing 24. In this state, multiple bolts (fastening components) 75 are inserted into the first through holes 48 formed in the upper annular flange 44 and the first through holes 34 formed in the lower annular flange 30. Welded nuts (fastening components) 76 are screwed into the lower parts of the bolts 75 protruding downward from the first through holes 34, and the heads of the bolts 75 are pressed against the upper surface of the upper annular flange 44. As a result, the pressing protrusions 40S are pressed against the upper surface of the main housing 55 of each battery cell 54 of the uppermost planar battery cell 68 constituting the battery stack 52. Thus, the battery module 20 is completed.

[0033] like Figure 1 as well as Figure 2 As shown, the battery module 20 is fixed to the left and right lower side beams 12. Specifically, with the upper surface of the left edge of the upper annular flange 44 in contact with the lower surface of the base plate 13 of the left lower side beam 12, and the upper surface of the right edge of the upper annular flange 44 in contact with the lower surface of the base plate 13 of the right lower side beam 12, the bolts 78 are inserted from below into the second through holes 35 and 49 of the lower annular flange 30 and the upper annular flange 44. Furthermore, the upper part of each bolt 78 engages with the corresponding welding nut 15, and the head of each bolt 78 presses against the lower surface of the base plate 13. Thus, when the battery module 20 is fixed to the left and right lower side beams 12 using multiple bolts 78, as... Figure 6 As shown, the upper surface of the upper housing 38 is pressed against the lower surface of the crossbeam 17.

[0034] (Functions and Effects)

[0035] Next, the function and effects of this embodiment will be explained.

[0036] The battery mounting structure in the vehicle described above includes a battery stack 52, which is constructed by stacking multiple rectangular battery cells 54, each having a positive terminal 60 and a negative terminal 62 at both ends in the longitudinal direction, in a cuboid shape, along their thickness direction. The lower housing 24 houses the battery stack 52 such that the thickness direction of the battery cells 54 aligns with the vertical direction. When the lower housing 24 and the upper housing 38 are fastened using bolts 75 and weld nuts 76 as fastening components, a vertical force (the thickness direction of the battery cells 54) is applied to the battery stack 52 from the bottom plate 26 of the lower housing 24 and the pressing protrusions 40S of the upper housing 38. Furthermore, the lower surface of the crossbeam 17 extending along the vehicle width direction applies a downward force in the thickness direction of the battery cells 54 to the upper surface of the upper housing 38. Thus, the battery mounting structure in this embodiment, by utilizing the crossbeam 17, the lower housing 24, and the upper housing 38, can apply pressure in the thickness direction to each battery cell 54 without the need for spacers. Therefore, it is easy to increase the energy density of the battery module 20 having the lower housing 24, the upper housing 38, and the battery stack 52.

[0037] It should be noted that when battery cells are stacked in a front-to-back direction to form a battery stack, and this battery stack is placed inside the lower housing, spacers are inserted between the two ends of the battery stack and the inner surfaces of the front and rear plates of the lower housing. However, in order to increase the pressure applied to the battery stack, it is necessary to increase the number of battery cells constituting the battery stack. Therefore, it is not easy to insert the battery stack and spacers between the front and rear plates. In contrast, in the battery module 20 of this embodiment, battery cells 54 are stacked in a vertical direction, and the battery stack 52 is sandwiched between the lower housing 24 and the upper housing 38 in a vertical direction. Therefore, even if the number of planar battery cells 68 is increased to increase the pressure applied to each battery cell 54, assembling the battery module 20 is not difficult.

[0038] Furthermore, a single cooler 72 is inserted into each gap 70 formed between each planar battery cell 68, so that each cooler 72 contacts each battery cell 54 of the planar battery cell 68 located above and below it. Therefore, multiple battery cells 54 can be cooled by a small number of coolers 72.

[0039] Furthermore, for example, if an internal short circuit causes the pressure inside at least one battery cell 54 to reach a predetermined pressure, safety valves 64 and 66 open, discharging smoke generated inside the battery cell 54 to the outside of the battery cell 54. It should be noted that, for example, an internal short circuit may occur if a small foreign object located outside the battery cell 54 enters the battery cell 54 through the gap between the main body housing 55 and the cover 58. In this case, an internal short circuit occurs near the cover 58 inside the battery cell 54. Therefore, in the event of such a short circuit, smoke generated near the cover 58 inside the battery cell 54 can be efficiently discharged to the outside of the battery cell 54 through safety valves 64 and 66 provided on the cover 58.

[0040] Furthermore, since the battery casing 22 of the battery module 20 has multiple heat dissipation holes 29S, smoke discharged from the safety valves 64 and 66 located on the left and right edges of the battery stack 52 (planar battery unit 68) can be discharged to the outside of the battery module 20 through the gaps between the battery stack 52 and the side plate portion 29 via each heat dissipation hole 29S. Additionally, the battery module 20 can discharge smoke discharged from the safety valves 64 and 66 located opposite each linear gap 69 through each linear gap 69 and the gaps between the battery stack 52 and the front plate portion 27, the rear plate portion 28, and the side plate portion 29 via each heat dissipation hole 29S.

[0041] Furthermore, for example, when battery cells are stacked in the front-to-back direction to form a battery stack, spacers are inserted between the two ends of the battery stack and the inner surfaces of the front plate 27 and the rear plate 28. Therefore, the front plate 27 and the rear plate 28 need to be approximately parallel to the vertical direction. However, in the case where such spacers are not present, as in this embodiment, the front plate 27 and the rear plate 28 are tilted relative to the vertical direction. That is, since the battery module 20 does not require such spacers, the design of the lower housing 24 (front plate 27, rear plate 28) has a high degree of freedom.

[0042] The battery module 20 in the vehicle according to the embodiments has been described above, but appropriate design changes can be made without departing from the spirit of the present invention.

[0043] For example, the number of battery cells 54 constituting each planar battery cell 68 may also be different from the number described above.

[0044] The battery stack 52 may also have two or more planar battery cells 68.

[0045] Alternatively, the pressing protrusion 40S can be omitted from the upper housing 38, so that the top plate 40 contacts the upper end of the battery stack 52.

[0046] Alternatively, a safety valve 64 (66) may be provided only on one cover 58 of the battery cell 54.

[0047] The planar shape of each cooler 72 can also be different from the planar shape of the planar battery cell 68. For example, the planar shape of each cooler 72 can also be the same as the overall planar shape of all the battery cells 54 (10 battery cells 54 in the embodiment) arranged in the front-back direction. That is, four coolers can also be provided in the gap 70. In this case, the smoke flowing from the battery cells 54 (safety valves 64, 66) of each planar battery cell 68 to each linear gap 69 flows between the vertically arranged linear gaps 69 through the gaps between adjacent coolers in the left-right direction, so that the smoke can be efficiently discharged to the outside of the battery module 20 from each heat dissipation hole 29S.

[0048] Ribs extending linearly in the front-rear direction and in the left-right direction can also be provided on the bottom surface (upper surface) of the base plate portion 26 of the lower housing 24. The upper ends of these ribs are located below the lower ends of the positive terminals 60 and negative terminals 62 of the battery cells 54 placed on the bottom surface of the base plate portion 26. Furthermore, the ribs extending in the front-rear direction can be located in the linear gaps 69 of the bottommost planar battery cells 68, or the ribs extending in the left-right direction can be located between the left and right adjacent battery cells 54 of the bottommost planar battery cells 68. In this way, the base plate portion 26 can be mechanically strengthened by the ribs, and the battery stack 52 can be positioned relative to the lower housing 24 in the front-rear direction and the left-right direction by the ribs.

[0049] Alternatively, a component different from the crossbeam 17 and the upper housing 38 may be sandwiched between the lower surface of the crossbeam 17 and the upper surface of the upper housing 38. In this case, a downward force is applied from the lower surface of the crossbeam 17 to the upper surface of the upper housing 38 via this component.

Claims

1. A battery mounting structure in a vehicle, wherein, The battery mounting structure in the vehicle includes: A battery stack is constructed by stacking multiple rectangular batteries with terminals on both ends in the length direction and in a cuboid shape along the thickness direction of the rectangular batteries. The lower housing has an opening on its upper surface to house the battery stack in such a way that the thickness direction is consistent with the vertical direction; An upper housing is mounted on top of the lower housing in a manner that blocks the opening, and has an opening on its lower surface; Fastening components fasten the lower housing and the upper housing by applying a force in the thickness direction from the lower housing and the upper housing to the battery stack; as well as A crossbeam, which is part of a vehicle frame component that supports the lower housing and the upper housing, extends along the width direction of the vehicle, and the lower surface of the crossbeam applies a force in the thickness direction to the upper surface of the upper housing.

2. The battery mounting structure in a vehicle according to claim 1, wherein, The battery stack has multiple planar battery cells formed by arranging multiple square batteries on a plane orthogonal to the thickness direction. The plurality of the planar battery cells are arranged along the thickness direction. A single cooler is provided in the gap between two adjacent planar battery cells, which contacts each of the square batteries constituting the planar battery cell.

3. The battery mounting structure in a vehicle according to claim 1 or 2, wherein, The lower surface of the crossbeam is in contact with the upper surface of the upper housing.

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