Battery pack

Abstract

To suppress an increase of vertical input load on a busbar.SOLUTION: In a battery pack, a housing of the battery pack accommodating one or two or more battery modules has a partitioning wall part and an upper cover member which is arranged so as to cover a busbar from above. An upper end part of the partitioning wall part includes a first portion which does not overlap the busbar in plane view, and a second portion which overlaps the busbar. An overlapping portion of the busbar that overlaps the second port in plan view is arranged above the second portion. The upper cover member has a first opposing part that lies opposite the first portion in a vertical direction, and a second opposing part that lies opposite the overlapping part in the vertical direction. In the vertical direction, a first distance between the first portion and the first opposing part is smaller than a total sum of a second distance between a lower end part of the overlapping part and the second portion, and a third distance between an upper end part of the overlapping part and the second opposing part.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] The following Patent Document 1 discloses a floor structure for an electric vehicle having a lower floor below an upper floor and separated from the upper floor. The upper floor includes side members and side sills on the outside thereof, the lower floor includes a battery mounting portion provided with members arranged in a lattice pattern, a frame is provided around the mounting portion that is detachably attached to the side members of the upper floor, and an extension frame is provided at approximately the center of the frame in the front-rear direction, extending outward and detachably attached near the center pillar mounting portion of the side sill. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2936959 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a battery pack, when a load is input from below to the battery pack, the load is transmitted to the floor panel via the bus bar, which can result in a large vertical load being input to the bus bar.

[0005] An object of the present invention is to suppress an increase in the vertical input load to the bus bar. [Means for solving the problem]

[0006] In a battery pack according to one aspect of the present invention, a housing of the battery pack that houses one or more battery modules has a partition wall portion and an upper cover member arranged to cover the bus bar from above. An upper end portion of the partition wall portion includes a first portion that does not overlap with the bus bar in a plan view and a second portion that overlaps with the bus bar. An overlapping portion of the bus bar that overlaps with the second portion in a plan view is arranged above the second portion. The upper cover member has a first opposing portion that faces the first portion in the vertical direction and a second opposing portion that faces the overlapping portion in the vertical direction. In the vertical direction, a first distance between the first portion and the first opposing portion is smaller than the sum of a second distance between a lower end portion of the overlapping portion and the second portion and a third distance between an upper end portion of the overlapping portion and the second opposing portion. Effect of the Invention

[0007] According to the present invention, it is possible to suppress an increase in the vertical input load to the bus bar. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic partial side view for explaining a battery pack according to an embodiment, showing an arrangement position of the battery pack in a vehicle. [Diagram 2] FIG. 2 is a partial perspective view showing an arrangement relationship between the battery pack and a floor panel according to the embodiment. [Diagram 3] FIG. 13 is a diagram for explaining a battery pack according to an embodiment, and is a schematic partial plan view showing the arrangement relationship between a lower cover member, a battery module, a partition wall portion, and a bus bar. [Figure 4] 1 is a diagram for explaining a battery pack according to an embodiment, and is a schematic partial plan view showing the arrangement relationship between a floor panel, a lower cover member, a partition wall portion, and a bus bar. FIG. [Diagram 5] 1 is a diagram for explaining a battery pack according to an embodiment, and is a schematic partial front oblique view showing the arrangement relationship between a floor panel, a lower cover member, a partition wall portion, and a bus bar. FIG. [Figure 6]This is a schematic partial cross-sectional view showing key parts in a cross section along line AA in Figure 5 to explain the battery pack of the embodiment, and is a diagram showing the arrangement relationship between the floor panel, the upper cover member, the lower cover member, the partition wall portion, and the bus bar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a battery pack according to an embodiment will be described with reference to the drawings. In each drawing, FR and RR indicate the front and rear in the vehicle longitudinal direction, LH and RH indicate the left and right in the vehicle width direction, and UP and DN indicate the upper and lower in the vehicle vertical direction. In the following description, the front and rear in the vehicle longitudinal direction, and the upper and lower in the vehicle vertical direction are simply referred to as the "vehicle front", "vehicle rear", "upper", and "lower", respectively. Elements having the same function are given the same reference numerals, and duplicated descriptions will be omitted.

[0010] The battery pack 1 according to the embodiment includes a housing 5, a partition wall portion 12, a battery module 20, and a bus bar 30.

[0011] 1 and 2, the battery pack 1 is disposed below a floor panel 50 of the vehicle V. The vehicle V is an electric vehicle driven by an electric motor (not shown), and the battery pack 1 is used as a power source that supplies power for driving the vehicle V. The battery pack 1 may be fixed to the underside of the vehicle V by fastening the peripheral portion of the housing 5 to a vehicle body frame member such as a side sill 51 via fasteners such as bolts (not shown).

[0012] 2, the floor panel 50 is a plate-like member having a substantially rectangular shape in a plan view, which separates the inside and outside of the vehicle V and is made of a metal such as iron or steel. A pair of side sills 51 extending in the front-rear direction of the vehicle are joined to both ends of the floor panel 50 in the vehicle width direction. In addition, cross members 52a, 52b extending in the vehicle width direction between the side sills 51 are joined to the upper surface of the floor panel 50. The side sills 51 and the cross members 52a, 52b may be made of a metal such as iron or steel.

[0013] In the illustrated example, the cross members 52a and 52b are elongated members having a generally hat-shaped cross section that opens downward. In the vehicle front-rear direction, the cross member 52a is disposed on the vehicle front side of the floor panel 50, and the cross member 52b is disposed on the vehicle rear side of the cross member 52a.

[0014] Furthermore, a front side member extension 53, a front center member 55a, and a floor member 55b are joined to the upper surface of the floor panel 50. This improves the rigidity of the floor panel 50 in the vehicle front-rear direction. Note that each of these members may be made of metal such as iron or steel.

[0015] The front center member 55a and the front side member extension 53 are disposed to extend in the vehicle front-rear direction on the vehicle front side of the cross member 52a. The front center member 55a is a member having a substantially M-shaped cross section that opens downward. The front side member extension 53 is a long member having a substantially hat-shaped cross section that opens downward.

[0016] As shown in the figure, the front center member 55a is disposed in the center in the vehicle width direction. The front side member extensions 53 are disposed as a pair on the left or right side of the front center member 55a in the vehicle width direction, spaced a predetermined distance from the front center member 55a. The front center member 55a and the front side member extensions 53 are joined at their vehicle front ends to a dash panel (not shown) and at their vehicle rear ends to the cross member 52a by a joining means such as welding.

[0017] The floor member 55b is an elongated member disposed between the cross members 52a and 52b and having a generally hat-shaped cross section that opens downward. The floor members 55b extend in the vehicle front-rear direction as a pair on the left or right of the center of the floor panel 50 at a predetermined distance in the vehicle width direction. The front end of the floor member 55b is joined to the cross member 52a, and the rear end is joined to the cross member 52b by a joining means such as welding.

[0018] When the battery pack 1 is disposed under the floor panel 50, the front center member 55a and the floor member 55b extend in a direction intersecting with the partition wall portion 12 described later. In addition, in a cross section perpendicular to the vehicle front-rear direction at each position in the vehicle front-rear direction, the front center member 55a and the floor member 55b are disposed as reinforcing members 55 disposed at a position closest to the center in the vehicle width direction. For example, in a region of the floor panel 50 on the vehicle front side of the cross member 52a, the front center member 55a is disposed at a position closest to the center in the vehicle width direction. In addition, in a region between the cross members 52a and 52b, the floor member 55b is disposed at a position closest to the center in the vehicle width direction. That is, the front center member 55a and the floor member 55b are disposed at a position closest to the center in the vehicle width direction at each position in the vehicle front-rear direction.

[0019] The center of gravity of the vehicle V is located in the center in the vehicle width direction in a plan view. Therefore, for example, when the vehicle V goes over a step or the like while traveling, if an upward thrust load, which is a load input from below, is input to the vehicle V, a larger proportion of the upward thrust load is input to the center in the vehicle width direction of the floor panel 50. Here, the floor panel 50 includes a front center member 55a and a floor member 55b as reinforcing members 55. Therefore, the area where the reinforcing members 55 are arranged is a high-strength portion with high rigidity in the vertical direction. As a result, even if an upward thrust load is input, deformation of the center in the vehicle width direction of the floor panel 50 is suppressed.

[0020] The battery pack 1 has a housing 5 as an exterior member that houses one or more battery modules 20. The housing 5 has a hollow rectangular box shape, and has a flat shape in which the dimension in the vertical direction of the vehicle is smaller than the dimensions in the front-rear direction or width direction of the vehicle as a whole. The shape of the housing 5 can be appropriately set depending on the shape and dimensions of the battery pack 1, the installation method in the vehicle V, and the like. The housing 5 may house auxiliary devices (not shown), such as a controller, switch, relay, etc., that manage the capacity, voltage, temperature, etc. of the battery module 20.

[0021] 6, the housing 5 includes an upper cover member 6 and a lower cover member 10. The upper cover member 6 and the lower cover member 10 are fastened to each other at their peripheral portions via fasteners such as bolts (not shown). The housing 5 is sealed by closing the upper opening of the lower cover member 10 with the upper cover member 6.

[0022] A sealing member (not shown) made of a rubber material or the like may be interposed at the contact portion between the upper cover member 6 and the lower cover member 10. Also, the housing 5 may be sealed by closing the upper opening of the lower cover member 10 with a floor panel 50 instead of the upper cover member 6. In that case, the floor panel 50 corresponds to the upper cover member 6.

[0023] 3 to 6, the lower cover member 10 is a bottomed box-shaped member that is open at the top and made of a metal such as aluminum, and has a substantially rectangular shape in a plan view. In the example shown in FIG. 3, the battery modules 20 are stacked in one layer in the vehicle front side area of ​​the bottom 11 of the lower cover member 10, with two rows in the vehicle width direction and four rows in the vehicle front-rear direction. Also, the battery modules 20 may be stacked in two layers, one above the other, with two rows in the vehicle width direction and two rows in the vehicle front-rear direction, in the vehicle rear side area of ​​the lower cover member 10. Note that the lower cover member 10 may be provided with only one battery module 20.

[0024] The battery module 20 incorporates battery cells (not shown). For example, the battery module 20 may be configured by arranging a plurality of flat battery cells, whose dimension in the vehicle width direction is shorter than the dimension in the vehicle front-rear direction, in parallel in the vehicle width direction and electrically connecting them, and integrating the plurality of battery cells with a module case, which is an exterior member of the battery module 20. Furthermore, electrodes of the battery cells are electrically connected to terminals arranged on the outer circumferential surface of the battery module 20 via a bus bar unit (not shown). The battery module 20 may incorporate only one battery cell.

[0025] The battery cell is configured by, for example, laminating a positive electrode plate and a negative electrode plate with a separator interposed therebetween, and sealing the power generating element together with an electrolyte in an exterior member such as an aluminum can. In one embodiment, the battery cell is a lithium ion secondary battery.

[0026] A partition wall portion 12 that divides the inside of the housing 5 is provided on the bottom portion 11 of the lower cover member 10. In the illustrated example, the partition wall portion 12 is a plate-like member that extends in the vehicle width direction and has a substantially rectangular shape when viewed in the vehicle front-rear direction. Therefore, the extension direction of the reinforcing member 55 of the floor panel 50 described above intersects with the extension direction of the partition wall portion 12. By providing such a partition wall portion 12, the rigidity of the battery pack 1 in the vehicle width direction or the vertical rigidity can be improved.

[0027] In the illustrated example, a plurality of partition wall portions 12 are erected at a predetermined interval in the vehicle front-rear direction. A battery module 20 is disposed between each of the partition wall portions 12. In other words, the partition wall portions 12 separate the plurality of battery modules 20 from each other. In this manner, contact between the battery modules 20 can be suppressed when an external force is applied to the battery pack 1.

[0028] The form of the partition wall portion 12 is not limited to the illustrated example. The partition wall portion 12 may extend in the vehicle longitudinal direction, or may extend in a horizontal or oblique direction that intersects with the vehicle longitudinal direction and the vehicle width direction. In addition, the number of partition wall portions 12 erected on the bottom portion 11 may be one. The shape of the partition wall portion 12 may be appropriately set depending on the shape of the battery pack 1, the shape of the battery module 20, etc.

[0029] 6, the partition wall portion 12 has an upper end portion 13 that faces the upper cover member 6 in the vertical direction. The upper side of the partition wall portion 12 may be configured as a separate part. In the illustrated example, the partition wall portion 12 includes a main body portion 12a and an additional portion 12b that is fastened and fixed to the upper side of the main body portion 12a by a bolt.

[0030] Furthermore, the additional portion 12b may include an elastic portion 12c made of foamed polyurethane or the like on the upper side. In this case, the upper surface of the elastic portion 12c of the upper end portion 13 is located at the uppermost position in the partition wall portion 12.

[0031] In the illustrated example, the additional portion 12b is disposed on a part of the upper side of the main body portion 12a, but the additional portion 12b may be disposed on the entire upper side of the main body portion 12a. In one embodiment, the total value of the vertical dimension of the additional portion 12b and the elastic portion 12c may be 5 mm to 20 mm.

[0032] At least a part of the upper end 13 of the partition wall portion 12 is located at a position higher than the upper surface of the battery module 20. In addition, a bus bar 30 (described later) is disposed between the upper end 13 and the upper cover member 6. In the illustrated example, the bus bar 30 is disposed so as to pass through an opening O, which is formed between the main body 12a of the partition wall portion 12 and the upper cover member 6 and opens in a direction intersecting the partition wall portion 12, in the front-rear direction of the vehicle.

[0033] The bus bar 30 is formed by covering a conductor portion made of a metal such as copper with an insulating portion made of an insulating material such as resin. As shown in Fig. 3, the bus bar 30 extends in the front-rear direction of the vehicle above the battery modules 20 and the partition wall portion 12.

[0034] The bus bar 30 is a member that electrically connects one or more battery modules 20 to electrical components arranged inside or outside the housing 5, or electrically connects two or more battery modules 20 to each other. In the illustrated example, the bus bar 30 electrically connects the battery module 20 to a junction box (not shown) equipped with a high-voltage relay and fuse arranged on the vehicle front side of the battery pack 1, and a distribution box (not shown) to which an electric motor is connected arranged on the vehicle rear side of the battery pack 1. Therefore, the power output by the battery module 20 is supplied to the electric motor via the bus bar 30. Note that the location of the electrical components such as the junction box or the distribution box is not limited to inside the housing 5, and may be arranged outside.

[0035] As described above, the bus bar 30 is disposed so as to pass through the battery modules 20 and the upper side of the partition wall portion 12. Therefore, as shown in Fig. 6, the upper end portion 13 of the partition wall portion 12 includes a first portion 13a that does not overlap with the bus bar 30 in a plan view, and a second portion 13b that overlaps with the bus bar 30. The second portion 13b is the region of the upper end portion 13 that is directly below the bus bar 30, and the first portion 13a is the other region.

[0036] An overlapping portion 31 of the busbar 30 that overlaps with the second portion 13b in a plan view is disposed above the second portion 13b. An upper end 31a of the overlapping portion 31 faces the upper cover member 6 in the vertical direction, and a lower end 31b faces the partition wall portion 12 in the vertical direction.

[0037] 3, a support member 32 made of an insulating material such as resin may be attached to the overlapping portion 31. The bus bar 30 can be disposed by fastening the support member 32 to the upper end portion 13 of the partition wall portion 12 using a fastener such as a bolt.

[0038] The upper cover member 6 is a plate-like member having a substantially rectangular shape in a plan view, and is made of a metal such as iron. As shown in Fig. 6, the upper cover member 6 is disposed so as to cover at least the partition wall portion 12 and the bus bar 30 from above. Therefore, the upper cover member 6 has a first opposing portion 6a that faces the first portion 13a of the partition wall portion 12 in the vertical direction, and a second opposing portion 6b that faces the overlapping portion 31 of the bus bar 30 in the vertical direction.

[0039] The upper cover member 6 illustrated in the drawings has a substantially flat cross section when viewed in the vehicle front-rear direction, but is not limited thereto. For example, the upper cover member 6 may further include a member that extends downward in a part thereof, or may have a part that bulges downward, thereby forming a downward extending portion that extends downward. Also, the first opposing portion 6a or the second opposing portion 6b may be the downward extending portion.

[0040] In addition, the region on the vehicle rear side of the upper cover member 6 may be formed with a bulge that bulges out more toward the upper part of the vehicle than the region on the vehicle front side, depending on the number of stages of the battery modules 20 arranged on the lower cover member 10. This allows more battery modules to be arranged on the vehicle rear side, making the battery pack 1 thinner overall and more space-saving while ensuring more battery capacity.

[0041] In the vertical direction, a first distance D1 between the first portion 13a of the partition wall portion 12 and the first opposing portion 6a of the upper cover member 6 is configured to be smaller than the sum of a second distance D2 between the lower end portion 31b of the overlapping portion 31 of the busbar 30 and the second portion 13b of the partition wall portion 12, and a third distance D3 between the upper end portion 31a of the overlapping portion 31 and the second opposing portion 6b of the upper cover member 6. In other words, the relationship of first distance D1<(second distance D2+third distance D3) is satisfied.

[0042] The first distance D1 refers to the smallest distance in the vertical direction between the first portion 13a of the partition wall portion 12 and the first opposing portion 6a of the upper cover member 6. The second distance D2 refers to the smallest distance in the vertical direction between the lower end portion 31b of the overlapping portion 31 of the busbar 30 and the second portion 13b of the partition wall portion 12. The third distance D3 refers to the smallest distance in the vertical direction between the upper end portion 31a of the overlapping portion 31 of the busbar 30 and the second opposing portion 6b of the upper cover member 6.

[0043] In the illustrated example, the first portion 13a of the partition wall portion 12 and the first opposing portion 6a of the upper cover member 6 are in contact with each other. Therefore, the value of the first distance D1 is zero. On the other hand, the lower end portion 31b of the overlapping portion 31 of the busbar 30 and the second portion 13b of the partition wall portion 12 are configured to be spaced apart by a predetermined distance. Also, the upper end portion 31a of the overlapping portion 31 and the second opposing portion 6b of the upper cover member 6 are configured to be spaced apart by a predetermined distance. Therefore, the sum of the second distance D2 and the third distance D3 is greater than the value of the first distance D1. That is, the above-mentioned magnitude relationship is satisfied.

[0044] The first portion 13a of the partition wall portion 12 and the first opposing portion 6a of the upper cover member 6 may be spaced apart by a predetermined distance. That is, the value of the first distance D1 may be greater than zero. The values ​​of the first distance D1, the second distance D2, and the third distance D3 are not particularly limited, and may be appropriately set depending on, for example, the vertical dimensions, shapes, or installation methods of the battery pack 1, the partition wall portion 12, the battery module 20, or the bus bar 30. In an embodiment, the total value of the second distance D2 and the third distance D3 may be 10 mm to 50 mm.

[0045] 4 and 5, when the battery pack 1 is disposed below the floor panel 50, the bus bar 30 may be disposed so as not to overlap the reinforcing member 55 in a plan view at each position in the vehicle front-rear direction. In the illustrated example, the bus bar 30 is disposed so as not to overlap the front center member 55a and floor member 55b, which are the reinforcing member 55, in a plan view.

[0046] The following describes the effects of the battery pack 1 according to the embodiment.

[0047] (1) A battery pack 1 according to an embodiment is disposed below a floor panel 50, and includes one or more battery modules 20 each having a built-in battery cell, a housing 5 for the battery pack 1 housing the one or more battery modules 20, a partition wall portion 12 erected on a bottom portion 11 of the housing 5 and dividing the interior of the housing 5, and a bus bar 30 electrically connecting the one or more battery modules 20 to an electric component disposed inside or outside the housing 5 or electrically connecting the two or more battery modules 20 to each other. The housing 5 has an upper cover member 6 disposed so as to cover the partition wall portion 12 and the bus bar 30 from above. An upper end portion 13 of the partition wall portion 12 includes a first portion 13a that does not overlap the bus bar 30 in a plan view, and a second portion 13b that overlaps the bus bar 30. The overlapping portion 31 of the busbar 30, which overlaps with the second portion 13b in a plan view, is disposed above the second portion 13b. The upper cover member 6 has a first opposing portion 6a that faces the first portion 13a in the vertical direction, and a second opposing portion 6b that faces the overlapping portion 31 in the vertical direction. In the vertical direction, a first distance D1 between the first portion 13a and the first opposing portion 6a is smaller than the sum of a second distance D2 between the lower end portion 31b of the overlapping portion 31 and the second portion 13b, and a third distance D3 between the upper end portion 31a of the overlapping portion 31 and the second opposing portion 6b.

[0048] According to the battery pack 1 according to the embodiment, even if an upward thrust load is input to the battery pack 1 when the vehicle V goes over a step or the like while traveling, the load is transmitted to the upper cover member 6 of the housing 5 or the floor panel 50 disposed above the battery pack 1 via the first portion 13a of the partition wall portion 12, as shown by an arrow B in Fig. 6. This prevents the bus bar 30 from being pinched between the partition wall portion 12 and the upper cover member 6 or the floor panel 50. This makes it possible to prevent an increase in the vertical input load to the bus bar 30 between the partition wall portion 12 and the upper cover member 6 or the floor panel 50.

[0049] (2) In the battery pack 1 according to the embodiment, when the battery pack 1 is disposed below the floor panel 50, at each position in the vehicle longitudinal direction, the bus bar 30 is extended on the floor panel 50 in a direction intersecting with the partition wall portion 12, and is disposed so as not to overlap in a plan view with the reinforcing member 55 disposed at a position closest to the center in the vehicle width direction.

[0050] At each position of the floor panel 50 in the vehicle longitudinal direction, a reinforcing member 55 such as a front center member 55a extending in the vehicle longitudinal direction is disposed at a position closest to the center in the vehicle width direction in order to increase the rigidity of the vehicle in the longitudinal direction. The area of ​​the floor panel 50 where the reinforcing member 55 is disposed is a high-strength portion having high rigidity in the vertical direction. Here, according to the battery pack 1 according to the embodiment, the bus bar 30 does not overlap with the reinforcing member 55 in a plan view. Therefore, when a thrust load is input to the battery pack 1, the bus bar 30 is not pinched between the high-strength portion of the floor panel 50 and the partition wall portion 12. Therefore, an increase in the vertical input load to the bus bar 30 can be more reliably suppressed between the partition wall portion 12 and the upper cover member 6 or the floor panel 50.

[0051] In the above embodiment, an electric vehicle has been described as an example, but it goes without saying that the battery pack 1 according to the embodiment can also be applied to a battery pack that supplies driving power for a hybrid vehicle. [Explanation of symbols]

[0052] 1 Battery pack 5. Cabinet 6 Upper cover member 6a 1st opposing part 6b 2nd opposing part 10 Lower cover member 11 Bottom 12 Partition wall 13 Upper end 13a Part 1 13b Part 2 20 Battery Module 30 Busbar 31 Overlap 31a Upper end 31b Lower end 50 Floor Panel 55 Reinforcement member

Claims

1. A battery pack disposed below a floor panel, One or more battery modules each having a built-in battery cell; a battery pack housing that houses the one or more battery modules; a partition wall portion provided on a bottom portion of the housing to partition an inside of the housing; a bus bar that electrically connects the one or more battery modules to an electric component disposed inside or outside the housing, or electrically connects the two or more battery modules to each other; Equipped with the housing includes an upper cover member disposed so as to cover the partition wall and the bus bar from above, an upper end portion of the partition wall portion includes a first portion that does not overlap with the bus bar in a plan view and a second portion that overlaps with the bus bar; an overlapping portion of the bus bar that overlaps with the second portion in a plan view is disposed above the second portion; The upper cover member has a first opposing portion that faces the first portion in the vertical direction and a second opposing portion that faces the overlapping portion in the vertical direction, In the up-down direction, a first distance between the first portion and the first opposing portion is smaller than a sum of a second distance between a lower end of the overlapping portion and the second portion, and a third distance between an upper end of the overlapping portion and the second opposing portion. Battery pack.

2. 2. The battery pack according to claim 1, wherein, when disposed below the floor panel, at each position in the vehicle fore-and-aft direction, the bus bar extends from the floor panel in a direction intersecting with the partition wall portion and is disposed so as not to overlap, in a plan view, with a reinforcing member disposed at a position closest to a center in the vehicle width direction.

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