Battery pack case

Abstract

To obtain a battery pack case which can absorb an impact even if an impact is applied thereto from a direction orthogonal to a direction of lamination of multiple cells in a plan view.SOLUTION: A battery pack case 10 includes: metallic cell cases 12 each of which houses multiple laminated cells 18 and has a bottom wall 14 on which the multiple cells 18 are placed and a peripheral wall 16 facing wall surfaces 18L, 18R directed in a direction orthogonal to a lamination direction of the cells 18 in a plan view; and resin cell dampers 20 each of which is integrally erected at the bottom wall 14 between the peripheral wall 16 and one of the wall surfaces 18L, 18R of the cell 18 by outsert molding and covers at least the one of the wall surfaces 18L, 18R when viewed in the orthogonal direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A battery pack case that houses a battery stack made up of multiple stacked cells and compresses and restrains the battery stack in the stacking direction has a structure that includes one side wall that abuts against one end of the housed battery stack and presses it toward the other side in the stacking direction, and another side wall that abuts against the other end of the housed battery stack and presses it toward one side in the stacking direction (see, for example, Patent Document 1). The one side wall and the other side wall are made of a first metal plate, a second metal plate that is located on the outside in the stacking direction and faces the first metal plate, and an intervening member that is interposed between them and has a lower density than the metal that makes them up. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-129474 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is still room for improvement in the structure of the battery pack case that can absorb impact (maintain high strength) when impact is applied from a direction perpendicular to the stacking direction of multiple cells in a plan view.

[0005] Therefore, an object of the present invention is to provide a battery pack case that can absorb impact even when the impact is applied from a direction perpendicular to the stacking direction of the multiple cells in a plan view. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention No. 1 Aspects ofThe battery pack case is a metal cell case that houses a plurality of stacked cells, the cell case having a bottom wall on which the plurality of cells are placed and a peripheral wall that faces a wall surface that faces in a direction perpendicular to the stacking direction of the cells in a plan view, and a resin cell damper that is integrally erected by outsert molding on the bottom wall between the peripheral wall and the wall surface of the cell, and that covers at least the wall surface when viewed from the perpendicular direction. The bottom wall is formed with a plurality of through holes for outsert molding the cell damper. .

[0007] No. 1 Aspects of According to the invention, a resin cell damper is integrally provided by outsert molding on the bottom wall of the cell case between the peripheral wall of the cell case and the wall surface facing in a direction perpendicular to the stacking direction of the cells, covering at least the wall surface as viewed from the perpendicular direction. 。

[0008] Here, the bottom wall of the cell case has a plurality of through holes for outsert molding the cell damper. It is formed. Therefore, the support rigidity of the bottom wall for the cell damper is improved compared to when a single through-hole for outsert molding the cell damper is formed in the bottom wall of the cell case. .

[0009] As a result, even if an impact is applied from a direction perpendicular to the stacking direction of the multiple cells in a plan view, the impact is absorbed by the cell damper. Impact absorption efficiency is improved with respect to impacts applied in a direction perpendicular to the cell stacking direction.

[0010] Also, Second aspect of the present invention The battery pack case is First Aspect The battery pack case The cell damper is approximately the same size as the surrounding wall. It is formed.

[0011] Second Aspect According to the invention, the cell The damper is almost the same size as the cell case wall. Therefore, The insulation between each cell and the cell case is improved, and the cell dampers are provided separately for each wall surface facing in a direction perpendicular to the stacking direction of each cell, for example. Compared to when the cell damper is installed, Bending The rigidity is improved, and the impact absorption efficiency is improved against an impact applied in a direction perpendicular to the stacking direction of the cells.

[0012] Furthermore, the present invention Third Aspect The battery pack case is A battery pack case according to the first or second aspect, a resin holding member that is integrally provided on the outer surface of the peripheral wall by outsert molding and that is capable of holding at least the wiring; of It is prepared.

[0013] Third Aspect According to the invention, a resin holding member capable of holding at least the wiring is integrally provided on the outer surface of the peripheral wall of the cell case by outsert molding. Therefore, even if an impact is applied from a direction perpendicular to the stacking direction of the multiple cells in a plan view, the impact is absorbed by the holding member.

[0014] Also, Fourth aspect of the present invention The battery pack case is Third Aspect In the battery pack case of claim 1, a plurality of the holding members are provided.

[0015] Fourth Aspect According to the invention, a plurality of holding members are provided, and therefore, compared to a case where a single holding member is provided, the impact absorption efficiency is improved with respect to an impact applied in a direction perpendicular to the stacking direction of the cells.

[0016] Also, Fifth aspect of the present invention The battery pack case is No. 1~ Fourth Any one of One aspect In this battery pack case, the bottom wall is formed in a rectangular shape with the stacking direction of the cells as its longitudinal direction, and the peripheral wall is formed to face a wall surface facing the stacking direction of the cells, and a resin end plate that contacts the wall surface is integrally formed by outsert molding on the inner surface of the peripheral wall that faces the wall surface facing the stacking direction of the cells.

[0017] Fifth AspectAccording to the invention, a resin end plate that contacts the inner surface of the peripheral wall of the cell case, which faces the wall surface facing the stacking direction of the cells, is integrally formed by outsert molding. Therefore, the length in the stacking direction of the battery pack case that houses a battery stack formed by stacking multiple cells is reduced compared to when the end plate is not integrally formed by outsert molding. This makes it possible to reduce the size of a gripping member, such as a robot hand, that grips the battery pack case when installing the battery pack case in a vehicle body. [Effects of the Invention]

[0018] As described above, according to the present invention, even if an impact is applied in a direction perpendicular to the stacking direction of the plurality of cells in a plan view, the impact can be absorbed. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic perspective view showing a battery pack case according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. [Figure 3] 2 is a schematic perspective view showing, in partial cross section, a cell damper that constitutes a part of the battery pack case according to the first embodiment. FIG. [Figure 4] 4A is a schematic plan view showing an enlarged view of a step portion of a bottom wall of a cell case that constitutes a battery pack case according to the first embodiment, and FIG. 4B is a schematic cross-sectional view taken along the line BB in FIG. [Figure 5] 3 is a schematic cross-sectional view showing a mold for manufacturing the battery pack case according to the first embodiment. FIG. [Figure 6] FIG. 10 is a schematic perspective view showing a battery pack case according to a second embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view taken along the line CC in FIG. 6. [Figure 8] FIG. 2 is a schematic perspective view showing a battery pack case provided with end plates. [Figure 9] FIG. 9 is a schematic cross-sectional view taken along the line DD in FIG. 8, showing the battery stack. [Figure 10] FIG. 10 is a schematic cross-sectional view corresponding to FIG. 9 showing a conventional battery pack case together with a battery stack. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For ease of explanation, the arrow UP shown in each drawing indicates the upward direction of the battery pack case, the arrow FR indicates the forward direction of the battery pack case, and the arrow RH indicates the rightward direction of the battery pack case. In the following description, unless otherwise specified, when directions such as up / down, front / rear, and left / right are mentioned, they refer to up / down in the up / down direction of the battery pack case, front / rear in the front / rear direction of the battery pack case, and left / right in the left / right direction of the battery pack case.

[0021] First Embodiment First, a first embodiment will be described. As shown in Fig. 1, a battery pack case 10 according to the first embodiment includes a metal cell case 12 that houses a plurality of stacked cells 18 (see Figs. 2 and 9). The cell cases 12 are provided in pairs, one on the left and one on the right, and in the following description, when it is necessary to distinguish between the left and right cell cases 12, the left cell case 12 will be referred to as "cell case 12L" and the right cell case 12 as "cell case 12R."

[0022] As shown in Figures 1 and 2, the cell case 12 is in the shape of a rectangular housing and has a bottom wall 14 having an approximately rectangular flat plate shape on which multiple cells 18 stacked in the front-to-back direction are placed, and a peripheral wall 16 having an approximately rectangular flat plate shape that faces left and right wall surfaces 18L, 18R (see Figures 2 and 9) that face a direction perpendicular to the stacking direction of the cells 18 when viewed in a plane, and front and rear wall surfaces 18F, 18B (see Figures 2 and 9) that face the stacking direction of the cells 18.

[0023] The bottom wall 14 has a rectangular, flat bottom wall main body 14A with its longitudinal direction extending in the front-to-rear direction, and step portions 15 formed on both left and right end portions of the bottom wall main body 14A. The step portions 15 are formed in a generally inverted "L" shape in cross section as seen from the front-to-rear direction so as to protrude upward, and the left and right end portions of the bottom walls 18D (see FIGS. 2 and 9) of each cell 18 are placed on its upper wall 15U to support each cell 18. In other words, a space S is formed between the bottom wall 18D of each cell 18 and the bottom wall main body 14A.

[0024] The peripheral wall 16 has left and right side wall portions 16L, 16R erected integrally from both left and right end portions of the step portion 15 (upper wall 15U) in the bottom wall 14, and front and rear side wall portions 16F, 16B erected integrally from both front and rear end portions of the bottom wall 14. The left and right side wall portions 16L, 16R are formed in the shape of rectangular flat plates with the front and rear direction as the longitudinal direction, and are formed to a height at least equal to the height of the cells 18.

[0025] The front and rear side wall portions 16F, 16B are cut out at their left and right lower end portions in a generally inverted "L" shape to conform to the shape of the step portion 15, and are formed in a generally inverted "convex" shape when viewed from the front-rear direction. The left and right side wall portions 16L, 16R and the front and rear side wall portions 16F, 16B are integrally continuous in the circumferential direction.

[0026] In addition, a flange portion 16A extending to the left (outward) is integrally formed at the upper end of the left side wall portion 16L of the cell case 12L, and a flange portion 16A extending to the right (outward) is integrally formed at the upper end of the right side wall portion 16R of the cell case 12R.

[0027] Additionally, the upper end of the left side wall 16L of the cell case 12R is bent in a crank shape so as to be close to the upper end of the right side wall 16R of the cell case 12L. That is, the upper end of the left side wall 16L of the cell case 12R protrudes leftward (outward) in a substantially "L" shape in a cross section seen from the front-to-rear direction (see FIG. 2).

[0028] As shown in Figures 1 to 3, in the cell case 12 (cell cases 12L, 12R), cell dampers 20 made of resin (including foamed resin) are integrally erected by outsert molding at the left-right center of the upper wall 15U of the step portion 15 between the left and right side wall portions 16L, 16R and the left and right wall surfaces 18L, 18R of the cell 18.

[0029] The cell damper 20 has a damper body 22 formed in the shape of a rectangular flat plate having approximately the same size (length and height) as the left and right side wall portions 16L, 16R so that it can cover at least the left and right wall surfaces 18L, 18R of each cell 18 when viewed from the left and right direction, and a fixing portion 24 formed at the lower end of the damper body 22 and fixed to the upper wall 15U of the step portion 15.

[0030] The fixing portion 24 is integrally formed by outsert molding so as to sandwich the upper wall 15U of the step portion 15 from above and below. That is, as shown in Fig. 4, a plurality of slit-shaped elongated hole portions 15A, each having a longitudinal direction in the front-rear direction, are bored as through-holes at predetermined intervals along the front-rear direction in the center of the left-right direction of the upper wall 15U of the step portion 15.

[0031] Therefore, as shown in Figure 5, the cell case 12 is placed in a mold 38 consisting of a core 38A and a cavity 38B, and then the void portion formed in the mold 38, i.e., the void portion that has the same shape as the cell damper 20, is filled with resin and solidified, resulting in a structure in which the peripheral portion (upper wall 15U) of each long hole portion 15A is clamped by the fixing portion 24.

[0032] That is, as shown in FIG. 3, the fixing portion 24 has an axial portion 24A that is filled into each long hole portion 15A, an upper flange portion 24B that protrudes integrally from the upper end of the axial portion 24A and is in close contact with the upper surface of the upper wall 15U of the step portion 15, and a lower flange portion 24C that protrudes integrally from the lower end of the axial portion 24A and is in close contact with the lower surface of the upper wall 15U of the step portion 15.

[0033] The fixing portions 24 allow the cell damper 20 to be integrally attached to the upper wall 15U of the step portion 15. The upper flange portion 24B and the lower flange portion 24C are formed so that their lengths in the front-to-rear direction are the same as the length of the damper body 22 in the front-to-rear direction, but this is not limited to this, and they may be formed only around each elongated hole portion 15A, for example.

[0034] Next, the operation of the battery pack case 10 according to the first embodiment configured as above will be described.

[0035] As shown in Figures 1 and 2, a resin cell damper 20 that covers at least the left and right wall surfaces 18L, 18R when viewed from the left and right is integrally erected by outsert molding on the step portion 15 of the bottom wall 14 between the left and right side wall portions 16L, 16R that constitute the peripheral wall 16 of the cell case 12 and the left and right wall surfaces 18L, 18R of the cell 18.

[0036] Therefore, even if an impact is applied to the multiple cells 18 from the left and right direction (a direction perpendicular to the stacking direction of the cells 18) in a plan view, the cell damper 20 can absorb the impact and suppress deformation of the cell case 12 due to the impact. In other words, the battery pack case 10 that houses the multiple stacked cells 18 can maintain high strength against impact.

[0037] Moreover, this cell damper 20 is formed to be approximately the same size as the left and right side wall portions 16L, 16R that constitute the peripheral wall 16 of the cell casing 12. Therefore, it is possible to improve the insulation between each cell 18 and the cell casing 12, and it is also possible to improve the bending rigidity of the cell damper 20 compared to when the cell damper 20 is provided separately for each of the left and right wall surfaces 18L, 18R of each cell 18. In other words, this cell damper 20 can improve the impact absorption efficiency for impacts applied from the left and right direction (the direction perpendicular to the stacking direction of the cells 18).

[0038] Furthermore, a plurality of elongated holes 15A for outsert molding the cell damper 20 are formed in the upper wall 15U of the step portion 15 in the bottom wall 14 of the cell casing 12. Therefore, the support rigidity of the upper wall 15U for the cell damper 20 can be improved compared to when a single large elongated hole 15A for outsert molding the cell damper 20 is formed in the upper wall 15U of the step portion 15. In other words, according to the first embodiment, it is possible to improve the impact absorption efficiency for impacts applied from the left-right direction (directions perpendicular to the stacking direction of the cells 18).

[0039] Furthermore, because the resin cell damper 20 is integrally attached to the cell case 12 by outsert molding in this way, the productivity of the battery pack case 10 can be improved compared to when a separately manufactured cell damper (not shown) is assembled to the cell case 12. Furthermore, because the cost of assembling the separately manufactured cell damper is not required, the manufacturing cost of the battery pack case 10 can be reduced.

[0040] Furthermore, since there is no need for transportation costs for transporting separately manufactured cell dampers, manufacturing costs can be reduced even further, and since there is no need to transport separately manufactured cell dampers by vehicle, etc., the carbon dioxide emitted from such vehicles, etc. can be reduced.

[0041] Second Embodiment Next, a second embodiment will be described. Note that the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed descriptions thereof will be omitted where appropriate.

[0042] As shown in Figures 6 and 7, this second embodiment does not have a cell damper 20, and instead, a resin holding member 30 capable of holding at least wiring (such as a bus bar) 36 is integrally formed by outsert molding on the outer surface of, for example, the left side wall portion 16L that constitutes the peripheral wall 16 of the left cell case 12L. This is the only difference from the first embodiment described above.

[0043] The holding member 30 has a hook portion 32 formed in a hook shape so that the wiring 36 can be fitted in from above, and a fixing portion 34 formed on the base side of the hook portion 32 and fixed to the side wall portion 16L. The holding member 30 is integrally formed by outsert molding so that the fixing portion 34 holds the side wall portion 16L from both the left and right.

[0044] That is, a plurality of circular holes 16C are formed at predetermined intervals along the front-rear direction in the approximate center of the side wall 16L in the up-down direction. Therefore, the cell case 12 is placed in a mold (not shown), and then the voids formed in the mold, i.e., the voids having the same shape as the holding member 30, are filled with resin and solidified, whereby the peripheral edge of each hole 16C (side wall 16L) is clamped by the fixing portion 34.

[0045] That is, the fixing portion 34 has an axial portion 34A that fills each hole 16C, an outer flange portion 34B that protrudes integrally from the left end of the axial portion 34A and is in close contact with the outer surface of the side wall portion 16L, and an inner flange portion 34C that protrudes integrally from the right end of the axial portion 34A and is in close contact with the inner surface of the side wall portion 16L. The fixing portion 34 allows a plurality of holding members 30 (for example, five in the illustrated example) to be attached integrally to the side wall portion 16L.

[0046] Next, the operation of the battery pack case 10 according to the second embodiment configured as described above will be described. Note that the description of the operation common to the first embodiment will be omitted as appropriate.

[0047] 6 and 7, for example, a resin holding member 30 capable of holding at least the wiring 36 is integrally provided by outsert molding on the outer surface of the left side wall portion 16L that constitutes the peripheral wall 16 of the left cell case 12L. Therefore, even if an impact is applied to the multiple cells 18 from the left side (a direction perpendicular to the stacking direction of the cells 18) in a plan view, the holding member 30 can absorb the impact and suppress deformation of the cell case 12 due to the impact. In other words, the battery pack case 10 that houses the multiple stacked cells 18 can maintain high strength against impact.

[0048] Moreover, a plurality of the retaining members 30 are provided along the front-rear direction (the longitudinal direction of the side wall portion 16L). Therefore, compared to when a single retaining member 30 is provided, the impact absorption efficiency can be improved with respect to an impact applied from the left side of the cell 18 (the direction perpendicular to the stacking direction of the cells 18).

[0049] Furthermore, because the resin holding member 30 is attached integrally to the cell case 12 by outsert molding in this manner, the productivity of the battery pack case 10 can be improved compared to when a separately manufactured holding member (not shown) is assembled to the cell case 12. Furthermore, because the cost of assembling the separately manufactured holding member is unnecessary, the manufacturing cost of the battery pack case 10 can be reduced.

[0050] <Common matters> Also, as shown in Figures 8 and 9, in the first and second embodiments, end plates 26 that face the front and rear wall surfaces 18F, 18B facing the stacking direction of multiple cells 18 stacked in the front-to-rear direction may be integrally formed on the front and rear side wall portions 16F, 16B of the cell case 12 by outsert molding.

[0051] The end plates 26 are provided on the front and rear side walls 16F, 16B, respectively, to compress and restrain the battery stack 17, which is made up of multiple stacked cells 18, in the stacking direction, and to abut against the front wall surface 18F of the battery stack 17 (cells 18) housed in the cell case 12, pressing it rearward, and to abut against the rear wall surface 18B, pressing it forward. Note that the cell damper 20 in the first embodiment and the holding member 30 in the second embodiment are omitted in Figures 8 and 9 to avoid complicating the drawings.

[0052] The end plate 26 has approximately the same size as the front and rear wall surfaces 18F, 18B of the cell 18, and includes a main body portion 28 disposed on the inner surfaces of the front and rear side wall portions 16F, 16B that constitute the peripheral wall 16 of the cell casing 12, and fixing portions 27 fixed to the front and rear side wall portions 16F, 16B, respectively. The end plate 26 is attached by sandwiching the side wall portions 16F and 16B from the front and rear directions between the fixing portions 27 and the main body portion 28.

[0053] That is, circular holes 16D are formed in the approximate centers of front and rear side walls 16F, 16B. Therefore, cell case 12 is placed in a mold (not shown), and then resin is filled into the gaps formed in the mold, i.e., the gaps having the same shape as end plates 26, and then hardened, whereby the peripheral edges of each hole 16D (side walls 16F and 16B) are sandwiched between fixing portion 27 and main body portion 28, respectively.

[0054] That is, the fixing portion 27 on the side wall 16F side has an axial portion 27A that fits into the hole 16D of the side wall 16F, and an outer flange portion 27B that integrally projects from the front end of the axial portion 27A and is in close contact with the outer surface of the side wall 16F. The fixing portion 27 allows the end plate 26 to be attached integrally to the side wall 16F.

[0055] Similarly, the fixing portion 27 on the side wall 16B side has an axial portion 27A that fits into the hole 16D of the side wall 16B, and an outer flange portion 27B that integrally projects from the rear end of the axial portion 27A and is in close contact with the outer surface of the side wall 16B. The fixing portion 27 allows the end plate 26 to be attached integrally to the side wall 16B.

[0056] In this way, when the end plate 26 is integrally formed with the cell case 12 by outsert molding, the length in the stacking direction of the battery pack case 10 containing the battery stack 17 formed by stacking multiple cells 18 can be reduced compared to when the end plate 26 is not integrally formed with outsert molding, for example, when the end plate 29 is incorporated into the cell case 12 as a separate body and fixed in the front-to-back direction by screws or the like, as shown in Figure 10.

[0057] Therefore, when the battery pack case 10 is installed in a vehicle body, the maximum distance in the front-to-rear direction of a gripping member (not shown), such as a robot hand, that grips the battery pack case 10 from the front-to-rear direction (the stacking direction of the cells 18) can be reduced. In other words, if the end plates 26 are integrally formed with the cell case 12 by outsert molding, the gripping member, such as a robot hand, that grips the battery pack case 10 can be made smaller. This reduces the power consumption of the power source that operates the gripping member.

[0058] Although the battery pack case 10 according to this embodiment has been described above with reference to the drawings, the battery pack case 10 according to this embodiment is not limited to the one shown in the drawings, and the design can be modified as appropriate within the scope of the gist of the present invention. For example, the battery pack case 10 may be provided with both the cell damper 20 of the first embodiment and the holding member 30 of the second embodiment.

[0059] Furthermore, in the second embodiment, although not shown, a plurality of holding members 30 may be integrally provided by outsert molding on the outer surface of the right side wall portion 16R that constitutes the peripheral wall 16 of the right cell case 12R. Furthermore, it is sufficient that the holding members 30 are formed in a shape that can hold at least the wires 36, and the holding members 30 may be configured to hold items other than the wires 36.

[0060] The shape of the cell casing 12 is not limited to the shape shown in the drawing. The holes 16D for attaching the end plates 26 by outsert molding may be formed in the front and rear side walls 16F and 16B, not just one each, but two (or more) each. In other words, the number of fixing portions 27 may be appropriately determined depending on the number of holes 16D. [Explanation of symbols]

[0061] 10 Battery pack case 12 Cell Case 14 Bottom wall 15A long hole (through hole) 16 Peripheral wall 18 cells 18L wall 18R Wall 20 Cell Damper 26 End plate 30 Retaining member

Claims

1. a metal cell case that houses a plurality of stacked cells, the cell case having a bottom wall on which the plurality of cells are placed and a peripheral wall that faces a wall surface that faces in a direction perpendicular to the stacking direction of the cells in a plan view; a resin cell damper that is integrally provided by outsert molding on the bottom wall between the peripheral wall and the wall surface of the cell, and that covers at least the wall surface when viewed from the perpendicular direction; Equipped with The battery pack case has a plurality of through holes formed in the bottom wall for outsert molding the cell damper.

2. 2. The battery pack case according to claim 1, wherein the cell damper is formed to have substantially the same size as the peripheral wall.

3. 3. The battery pack case according to claim 1, further comprising a resin holding member that is integrally formed on the outer surface of the peripheral wall by outsert molding and that is capable of holding at least the wiring.

4. A battery pack case as described in Claim 3, in which multiple holding members are provided.

5. The bottom wall is formed in a rectangular shape with the stacking direction of the cells as the longitudinal direction, and the peripheral wall is formed so as to face the wall surface facing the stacking direction of the cells, A battery pack case as described in any one of claims 1 to 4, wherein a resin end plate that contacts the wall surface is integrally formed by outsert molding on the inner surface of the peripheral wall opposite the wall surface facing the stacking direction of the cells.

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