Battery pack

Abstract

The present invention provides a battery pack that can suppress relative vertical movement of each battery cell in the battery module with respect to the case. [Solution] The battery module comprises a plurality of battery cells 63 stacked in a predetermined stacking direction, and a plurality of separators 70 located between two adjacent battery cells and sandwiching one battery cell from above and below, and a case 22 capable of housing the battery module, the case comprising a lower support portion 38 that supports the separators from below, and an upper pressing portion 49 that presses down on the separators from above.

Description

Technical Field

[0004] ,

[0006] ,

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

Background Art

[0002] Patent Document 1 below discloses a battery pack having a plurality of battery modules and a battery case for housing each battery module. Each battery module has a plurality of battery cells stacked in a predetermined direction and a module case for housing the plurality of battery cells.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is possible to provide a plurality of separators made of insulating members located between adjacent battery cells in the battery module of the battery pack of Patent Document 1 above. Patent Document 1 has room for improvement regarding suppressing each battery cell from moving relative to the module case in the vertical direction when such a design change is made.

[0005] In consideration of the above facts, an object of the present invention is to obtain a battery pack capable of suppressing each battery cell of a battery module from moving relative to a case in the vertical direction.

Means for Solving the Problems

[0006] The battery pack of the first embodiment comprises a battery module having a plurality of battery cells stacked in a predetermined stacking direction, and a plurality of separators located between two adjacent battery cells and sandwiching one battery cell from above and below, and a case capable of housing the battery module, wherein the case comprises a lower support portion that supports the separators from below and an upper pressing portion that presses down on the separators from above.

[0007] In the first embodiment of the battery pack, each battery cell is sandwiched from above and below by a separator. Furthermore, the case capable of housing the battery module includes a lower support portion that supports each separator from below and an upper pressing portion that presses each separator from above. Therefore, the battery pack of the first embodiment can suppress relative vertical movement of each battery cell of the battery module with respect to the case.

[0008] The battery pack of the second embodiment comprises, in the first embodiment, an upper case having an upper retaining portion and a lower end opening located below the upper retaining portion and through which the battery module can pass, and a lower case having a lower support portion and connected to the lower end of the upper case.

[0009] In the battery pack of the second embodiment, the battery module can be housed inside the upper case through the lower end opening of the upper case which has an upper retaining portion. Furthermore, when the lower case is connected to the lower end of the upper case in this state, each separator is sandwiched vertically between the upper retaining portion of the upper case and the lower support portion of the lower case.

[0010] In the third embodiment, the battery pack, when the direction perpendicular to the stacking direction in a plan view is defined as the orthogonal direction in the first or second embodiment, comprises a pair of upper retaining portions that are separated from each other in the orthogonal direction.

[0011] The battery pack case of the third embodiment is provided with a pair of upper retaining portions that are spaced apart from each other in orthogonal directions. Therefore, the battery pack of the third embodiment is more effective at suppressing relative vertical movement of each battery cell with respect to the case compared to the case in which the case is provided with only one upper retaining portion.

[0012] In the fourth embodiment of the battery pack, at least one of the upper pressing portion and the lower support portion is elastically deformable in any of the first to third embodiments.

[0013] In the fourth embodiment of the battery pack, at least one of the upper pressing portion and the lower support portion is elastically deformable. Therefore, even when there are variations in the vertical dimensions of each separator, the fourth embodiment of the battery pack can suppress relative vertical movement of each battery cell with respect to the case.

[0014] The fifth embodiment of the battery pack, in any of the first to fourth embodiments, comprises a pair of end plates that are separated from each other in the stacking direction and sandwich all the battery cells and all the separators in the stacking direction, the lower support portion supports the end plates from below, and the upper pressing portion presses the end plates from above.

[0015] In the fifth embodiment of the battery pack, the upper retaining portion and the lower support portion clamp the end plate from above and below. Therefore, the fifth embodiment of the battery pack can suppress relative vertical movement of each battery cell with respect to the case. [Effects of the Invention]

[0016] As described above, the battery pack according to the present invention has the excellent effect of suppressing relative vertical movement of each battery cell in the battery module with respect to the case. [Brief explanation of the drawing]

[0017] [Figure 1] This is a perspective view of the battery pack according to the embodiment, seen from above. [Figure 2] It is an exploded perspective view seen from above the battery pack. [Figure 3] It is a plan view of the battery pack. [Figure 4] It is a cross-sectional view taken along the 4-4 arrow line in FIG. 3. [Figure 5] It is a cross-sectional view taken along the 5-5 arrow line in FIG. 3. [Figure 6] It is a cross-sectional view taken along the 6-6 arrow line in FIG. 3. [Figure 7] It is a cross-sectional view taken along the 7-7 arrow line in FIG. 3. [Figure 8] It is a cross-sectional view taken along the 8-8 arrow line in FIG. 3.

Mode for Carrying Out the Invention

[0024] Furthermore, as shown in Figures 2 and 6, an annular plane 31, which is a plane perpendicular to the vertical direction, is formed at the lower end of the upper component 30. The planar shape of the annular plane 31 is a rectangle in which the front-to-back dimension is larger than the left-to-right dimension. The annular plane 31 has a pair of left and right fixed surfaces 32 that extend in the front-to-back direction when viewed from above. In addition, an annular connecting flange 36 is provided at the upper end of the upper component 30. The planar shape of the connecting flange 36 is a rectangle in which the front-to-back dimension is larger than the left-to-right dimension. The upper surface of the connecting flange 36 is a plane perpendicular to the vertical direction.

[0025] Lower support portions 38 are fixed to the upper surface of each fixed surface 32. Each lower support portion 38 is a rectangular prismatic member extending along the front-rear direction and is elastic. Each lower support portion 38 is made of, for example, sponge. The lower support portions 38 are provided along the entire length of the fixed surface 32 in the front-rear direction. The bottom surface of the lower support portion 38 is fixed to the fixed surface 32 in an airtight manner. Furthermore, the front end surface of the lower support portion 38 is fixed in an airtight manner to the front end surface of the inner circumferential surface of the upper component 30, and the rear end surface of the lower support portion 38 is fixed in an airtight manner to the rear end surface of the inner circumferential surface of the upper component 30.

[0026] Furthermore, one end of a ventilation duct (not shown) is connected to the front end opening 27 of the lower case 24. The other end of the ventilation duct is connected to a cooling fan (not shown) on the outside of the lower case 24.

[0027] The upper case 45 is a one-piece molded product made of die-cast aluminum. The hollow upper case 45 has an upper wall 46, a peripheral wall portion 52, and a connecting flange 57.

[0028] The planar shape of the upper wall 46 that constitutes the upper end of the upper case 45 is a rectangle in which the front-to-back dimension is greater than the left-to-right dimension. The upper wall 46 is a flat plate portion perpendicular to the vertical direction. An upper end opening 47 is formed in the upper wall 46 that penetrates the upper wall 46 in the vertical direction. The planar shape of the upper end opening 47 is a rectangle in which the front-to-back dimension is greater than the left-to-right dimension. The portions that constitute the left and right sides of the upper wall 46 are upper pressing portions 49 that extend linearly in the front-to-back direction in a plan view. The upper end of the peripheral wall portion 52 is connected to the outer peripheral edge of the upper wall 46. The annular peripheral wall portion 52 has a front wall portion 53, a rear wall portion 54, and a pair of side wall portions 55. As shown in Figures 4 to 6, the thickness of the front wall portion 53 and the rear wall portion 54 is greater than that of the side wall portions 55. The front and rear ends of the left side wall 55 are connected to the left ends of the front wall 53 and rear wall 54, respectively, and the front and rear ends of the right side wall 55 are connected to the right ends of the front wall 53 and rear wall 54, respectively. The lower surface of the circumferential wall 52 is a plane perpendicular to the vertical direction. Furthermore, in a plan view, the inner circumferential surface of the circumferential wall 52 is located on the outer side of the upper end opening 47. A lower end opening 56 is formed at the lower end of the circumferential wall 52 (see Figures 6 to 8). Furthermore, linear connecting flanges 57 extending in the front-rear direction are provided at the lower ends of both the left and right sides of the outer circumferential surface of the circumferential wall 52. The lower surface of each connecting flange 57 is a plane perpendicular to the vertical direction, and the lower surface of the connecting flange 57 is continuous with the lower surface of the circumferential wall 52.

[0029] The exhaust duct 58 shown in Figures 1 and 2 is a hollow member that extends in the front-to-rear direction and has openings on both the front and rear surfaces and the bottom surface. The front-to-rear dimensions of the exhaust duct 58 are larger than the front-to-rear dimensions of the upper end opening 47 of the upper case 45. As shown in Figures 1 and 3, the front end of the bottom surface of the exhaust duct 58 is fixed to the front end of the upper wall 46 of the upper case 45, and the rear end of the bottom surface of the exhaust duct 58 is fixed to the rear end of the upper wall 46 of the upper case 45.

[0030] As shown in Figure 2, the battery module 60 comprises a battery stack 61 and a pair of end plates 85 and 97.

[0031] As shown in Figure 2, the battery stack 61, which extends in the front-to-back direction in a plan view, comprises a plurality of battery cells 63, which are lithium-ion secondary batteries, and a plurality of separators 70, which are insulating members, located between adjacent battery cells 63.

[0032] Each battery cell 63 is rectangular in shape. The front shape of each battery cell 63 is a rectangle, with the left-right dimension being larger than the top-down dimension. A positive terminal 64 and a negative terminal 65 are provided on the top surface of each battery cell 63. As shown in Figures 2 and 3, the orientation of each battery cell 63 is set so that the positive terminal 64 and the negative terminal 65 are alternately arranged in the front-back direction in a plan view. Furthermore, a smoke exhaust section 66 is formed on the top surface of each battery cell 63, located between the positive terminal 64 and the negative terminal 65. The smoke exhaust section 66 is a thinner part of the top surface of the battery cell 63 compared to the surrounding area. That is, the mechanical strength of the smoke exhaust section 66 is lower than that of other parts of the top surface of the battery cell 63. For example, if the internal pressure of the battery cell 63 reaches a predetermined value due to an internal short circuit, the smoke exhaust section 66 will rupture. That is, the smoke exhaust section 66 will open. When the exhaust valve 66 opens, the internal components (debris) of the battery cell 63 are smoothly discharged to the outside of the battery cell 63 via the exhaust valve 66. These internal components include, for example, internal electrodes (current collector terminals), electrolyte, and gas (smoke).

[0033] Each resin separator 70 is a hollow member with a roughly rectangular parallelepiped shape and an open front. The separator 70 is an integrally molded product comprising a base plate portion 71, a bottom plate portion 72, side plate portions 73, an elastic support portion 74, a retaining portion 75, a projection 76, and a central pressing portion 78. The base plate portion 71, which has a rectangular front shape, has a vertical dimension smaller than its horizontal dimension. The bottom plate portion 72 protrudes forward from the lower edge of the base plate portion 71, and the left and right side plate portions 73 protrude forward from the left and right side edges of the base plate portion 71. The lower ends of the left and right side plate portions 73 are connected to the left and right side ends of the bottom plate portion 72, respectively. The upper ends of the left and right side plate portions 73 are located above the upper end of the base plate portion 71. A pair of left and right elastic support portions 74 protrude upward from the upper surface of the bottom plate portion 72 (see Figures 2 and 8). A pair of left and right retaining portions 75 are provided on both the left and right ends of the upper surface of the base plate portion 71 and on the inner surfaces of the left and right side plate portions 73. The left and right retaining portions 75 are flat plate-shaped parts perpendicular to the vertical direction, and their planar shape is a rectangle with a front-to-back dimension greater than the left-to-right dimension. The left and right retaining portions 75 are located below the upper end of the side plate portion 73. Furthermore, the front surfaces of the left and right retaining portions 75 are continuous with the front surfaces of the side plate portion 73. Furthermore, projections 76 are provided on the lower surfaces of the left and right retaining portions 75, pointing downward (see Figure 8). The rear part of the central retaining portion 78 is fixed to the center of the upper surface of the base plate portion 71 in the left-to-right direction. The central retaining portion 78 is a flat plate-shaped part perpendicular to the vertical direction, and its planar shape is a rectangle with a front-to-back dimension smaller than the left-to-right dimension. A smoke exhaust recess 79 is formed on the front edge of the central retaining portion 78. A pair of left and right projections 80 are provided on the lower surface of the central retaining portion 78, pointing downward (see Figure 8). The front end of the central retaining portion 78 and the front end surface of the side plate portion 73 are approximately aligned in the front-rear direction. The front-rear dimensions of the portions of the bottom plate portion 72 and the side plate portion 73 located in front of the front surface of the base plate portion 71 are slightly smaller than the front-rear dimensions of the battery cell 63. The left-right distance between the left and right side plate portions 73 is slightly larger than the left-right dimensions of the battery cell 63. Furthermore, when the elastic support portion 74, the retaining portion 75, the projection 76, the central retaining portion 78, and the projection 80 are in a free state, the vertical distance H1 (see Figure 2) between the upper end of the elastic support portion 74 and the lower ends of the projections 76 and 80 is smaller than the vertical dimension H2 (see Figure 2) of the battery cell 63.

[0034] As shown in Figure 2, the battery module 60 includes a pair of resin end plates 85 and 97. The front end plate 97 is located directly in front of the foremost battery cell 63, and the rear end plate 85 is located directly behind the rearmost battery cell 63.

[0035] As shown in Figures 2, 4, 5, and 8, one battery cell 63 is provided directly in front of each separator 70. Furthermore, the portion of the battery cell 63 excluding its front end is inserted into the space enclosed by the substrate portion 71, bottom plate portion 72, and side plate portion 73 of each separator 70. When the battery cell 63 is inserted into this space, as shown in Figure 8, the lower surface of the battery cell 63 contacts the upper ends of the left and right elastic support portions 74, and the lower ends of the left and right protrusions 76 and left and right protrusions 80 contact the upper surface of the battery cell 63. As described above, when the elastic support portion 74, retaining portion 75, protrusion 76, central pressing portion 78, and protrusion 80 are in a free state, the vertical distance H1 between the upper end of the elastic support portion 74 and the lower ends of the protrusions 76 and 80 is smaller than the vertical dimension H2 of the battery cell 63. Therefore, at least one of the elastic support portion 74, the retaining portion 75 (projection 76), and the central pressing portion 78 (projection 80) is elastically deformed by the battery cell 63. In other words, the battery cell 63 is sandwiched vertically by the elastic support portion 74 and the projections 76 and 80. As a result, the vertical relative movement of the battery cell 63 with respect to the separator 70 is substantially restricted. Furthermore, as shown in Figure 8, the inner surfaces of the left and right side plates 73 face the left and right sides of the battery cell 63 while forming a minute gap. As a result, the horizontal relative movement of the battery cell 63 with respect to the separator 70 is substantially restricted. In addition, the smoke exhaust portion 66 of the battery cell 63 is located directly below the smoke exhaust recess 79 of the central pressing portion 78.

[0036] Next, the structure of the rear end plate 85 will be described. The rear end plate 85 is a hollow resin member with a roughly rectangular parallelepiped shape and an open front. The end plate 85 is an integrally molded product comprising a base plate portion 86, a bottom plate portion 87, side plate portions 88, an elastic support portion 89, a retaining portion 90, a projection 91, and a central pressing portion 93. The vertical dimension of the base plate portion 86, which has a rectangular front shape, is smaller than its horizontal dimension. The thickness (front-to-back dimension) of the base plate portion 86 is greater than that of the base plate portion 71 of the separator 70. The bottom plate portion 87 protrudes forward from the lower edge of the base plate portion 86, and the left and right side plate portions 88 protrude forward from the left and right side edges of the base plate portion 86. The lower ends of the left and right side plate portions 88 are connected to the left and right side ends of the bottom plate portion 87, respectively. The upper ends of the left and right side plate portions 88 are located above the upper end of the base plate portion 86. A pair of left and right elastic support parts 89 are provided protruding upward from the upper surface of the bottom plate portion 87 (see Figures 2 and 7). A pair of left and right retaining parts 90 are provided on both the left and right ends of the upper surface of the base plate portion 86 and on the inner surfaces of the left and right side plate portions 88. The left and right retaining parts 90 are flat plate-shaped portions perpendicular to the vertical direction, and their planar shape is a rectangle with a front-to-back dimension greater than the left-to-right dimension. The left and right retaining parts 90 are located below the upper end of the side plate portion 88. Furthermore, the front surfaces of the left and right retaining parts 90 are continuous with the front surface of the side plate portion 88. Furthermore, projections 91 are provided protruding downward from the lower surfaces of the left and right retaining parts 90 (see Figure 7). The rear part of the central retaining part 93 is fixed to the center of the upper surface of the base plate portion 86 in the left-to-right direction. The central retaining part 93 is a flat plate-shaped portion perpendicular to the vertical direction, and its planar shape is a rectangle with a front-to-back dimension smaller than the left-to-right dimension. A smoke exhaust recess 94 is formed at the front edge of the central retaining portion 93. A pair of left and right protrusions 95 are provided on the lower surface of the central retaining portion 93, projecting downwards (see Figure 7). The front end of the central retaining portion 93 and the front end surface of the side plate portion 88 are approximately aligned in the front-rear direction. The front-rear dimensions of the portions of the bottom plate portion 87 and the side plate portion 88 located in front of the front surface of the base plate portion 86 are slightly smaller than the front-rear dimensions of the battery cell 63. The left-right distance between the left and right side plate portions 88 is slightly larger than the left-right dimensions of the battery cell 63. Also, when the elastic support portion 89, the retaining portion 90, and the protrusions 91 are in a free state, the vertical distance between the upper end of the elastic support portion 89 and the lower ends of the protrusions 91 and 95 is H1 (see Figure 2).

[0037] Next, the structure of the front end plate 97 will be described. The front end plate 97 is a roughly rectangular parallelepiped, integrally molded resin product. The vertical and horizontal dimensions of the end plate 97 are approximately the same as those of the end plate 85. The thickness (front-to-back dimension) of the end plate 97 is greater than the base portion 71 of the separator 70 and smaller than that of the end plate 85. The rear surface of the end plate 97 is made of a flat surface. Furthermore, upper end protrusions 98 are provided projecting upward from both the left and right ends of the upper end of the end plate 97.

[0038] As shown in Figures 2, 4, 5, and 7, one battery cell 63 is provided directly in front of the rear end plate 85. Most of the battery cell 63 is inserted into the space enclosed by the base plate portion 86, bottom plate portion 87, and side plate portion 88 of the end plate 85. When the battery cell 63 is inserted into this space, the lower surface of the battery cell 63 contacts the upper ends of the left and right elastic support portions 89, and the lower ends of the left and right protrusions 91 and left and right protrusions 95 contact the upper surface of the battery cell 63. As described above, when the elastic support portion 89, retaining portion 90, protrusion 91, central pressing portion 93, and protrusion 95 are in a free state, the vertical distance H1 between the upper end of the elastic support portion 89 and the lower ends of the protrusions 91 and 95 is smaller than the vertical dimension H2 of the battery cell 63. Therefore, at least one of the elastic support portion 89, retaining portion 90 (protrusion 91), and central pressing portion 93 (protrusion 95) is elastically deformed by the battery cell 63. In other words, the battery cell 63 is sandwiched vertically between the elastic support portion 89 and the protrusions 91 and 95. As a result, the relative vertical movement of the battery cell 63 with respect to the end plate 85 is substantially restricted. Furthermore, as shown in Figure 7, the inner surfaces of the left and right side plates 88 face the left and right sides of the battery cell 63 while forming a small gap. As a result, the relative horizontal movement of the battery cell 63 with respect to the end plate 85 is substantially restricted. In addition, the smoke exhaust portion 66 of the battery cell 63 is located directly below the smoke exhaust recess 94 of each central retaining portion 93.

[0039] The front end plate 97 is positioned directly in front of the furthest forward separator 70 (battery cell 63), and the rear end plate 85, which is integrated with the battery cell 63, is positioned directly behind the furthest rear separator 70.

[0040] The battery module 60 is held by a gripping device (not shown) on the outside of the lower case 24 and upper case 45, which are separated from each other. Specifically, the gripping device grips a pair of end plates 85 and 97 of the battery module 60 in the front-rear direction. As a result, the battery module 60 is slightly compressed in the front-rear direction by the gripping device. Therefore, the front surface of the battery cell 63 supported by the end plate 85 contacts the rear surface of the substrate portion 71 of the rearmost separator 70, and the front surface of the battery cell 63 supported by the frontmost separator 70 contacts the rear surface of the end plate 97. Furthermore, the front surface of each battery cell 63 supported by each separator 70 other than the frontmost separator 70 contacts the rear surface of the substrate portion 71 of the separator 70 directly in front of it. In addition, adjacent separators 70 face each other in the front-rear direction while forming a small gap between them. At this time, the front-rear dimension of the battery module 60 is slightly smaller than the front-rear dimension of the lower end opening 56 of the upper case 45. In other words, the front-to-back dimension of the battery module 60 is slightly smaller than the front-to-back dimension between the rear surface of the front wall portion 53 and the front surface of the rear wall portion 54. Furthermore, the left-to-right dimension of the battery module 60 is smaller than the left-to-right dimension of the lower end opening 56. Therefore, when the gripping device moves the battery module 60 directly below the lower end opening 56 and then moves upward, the upper part of the battery module 60 is housed in the internal space of the upper case 45 through the lower end opening 56.

[0041] As the gripping device moves further upward, as shown in Figures 6 to 8, the upper ends of the left and right side plates 73 of each separator 70, the upper ends of the left and right side plates 88 of the end plate 85, and the upper ends of the left and right upper end protrusions 98 of the end plate 97 come into contact with the lower surfaces of the left and right upper pressing portions 49, respectively. When the gripping device is then moved away from the battery module 60 and below the upper case 45, the compressive force applied to the battery module 60 by the gripping device disappears, causing the front end plate 97 to press against the rear surface of the front wall portion 53, and the rear end plate 85 to press against the front surface of the rear wall portion 54. That is, a reaction force in the front-rear direction is exerted on the battery module 60 from the front wall portion 53 and the rear wall portion 54, so that the battery module 60 is compressed in the front-rear direction. As a result, the state in which the battery module 60 is supported by the front wall portion 53 and the rear wall portion 54 of the upper case 45 is maintained.

[0042] Next, the connecting flange 36 of the lower case 24, which is positioned directly below the upper case 45, is brought into contact with the lower end surface of the upper case 45. As a result, as shown in Figures 6 to 8, the lower surfaces of the bottom plate portion 72 of each separator 70, the bottom plate portion 87 of the end plate 85, and the bottom surface of the end plate 97 come into contact with the upper surfaces of the left and right lower support portions 38 of the lower case 24, causing each lower support portion 38 to elastically deform. At this time, the upper pressing portion 49, which is in contact with the side plate portions 73, 88 and the upper end protrusion 98, may elastically deform in the vertical direction. In this state, the left and right sides of the connecting flange 36 of the lower case 24 and the left and right connecting flanges 57 of the upper case 45 are fixed to each other using fixing members. These fixing members include, for example, a plurality of bolts that pass through the connecting flanges 36 and 57 in the vertical direction, and a plurality of nuts that are screwed onto each bolt.

[0043] Furthermore, for example, the upper end opening 47 of the upper case 45 is used to connect multiple busbars (not shown) to the positive terminal 64 and negative terminal 65 of adjacent battery cells 63. This completes the battery pack 20. The case 22 containing the completed battery pack 20 is then fixed to the vehicle body.

[0044] (Mechanism of action and effect) Next, the operation and effects of the embodiment will be described.

[0045] As described above, in the battery pack 20 of this embodiment, the end plates 85 and 97 of the battery module 60 are pressed against the front wall 53 and rear wall 54 of the upper case 45. That is, the upper case 45 supports the battery module 60 by utilizing the force generated between the battery module 60 and the inner surface of the peripheral wall 52. Furthermore, each battery cell 63 is sandwiched from above and below by each separator 70 and end plate 85. Therefore, even if the battery pack 20 does not have a lower support portion 38 and an upper pressing portion 49, there is little risk of each battery cell 63 moving relative to each separator 70 and end plate 85 in the vertical direction when no external force is applied to the case 22.

[0046] However, if a large vertical impact load is applied to the case 22, for example, in the event of a collision with a vehicle, the force generated between the battery module 60 and the inner surface of the peripheral wall 52 may not be sufficient to maintain the vertical position of each battery cell 63 relative to the case 22 (upper case 45). In other words, the entire battery module 60 may bend in an arch shape when viewed from the side, and there is a risk of misalignment in the height of the upper surface of each battery cell 63. In particular, the reaction force generated on the inner surface of the peripheral wall 52 is less effective on multiple battery cells 63 (for example, 3 to 5 battery cells 63) located in the center of the longitudinal direction of the battery module 60, so misalignment in the height of the upper surface of these multiple battery cells 63 is likely to occur.

[0047] However, in the battery pack 20 of this embodiment, each separator 70 and end plate 85 supporting the battery cell 63 is sandwiched from above and below by the lower support portion 38 of the lower case 24 and the upper pressing portion 49 of the upper case 45. Therefore, even if a large vertical impact load is applied to the case 22, the entire battery module 60 will bend in an arch shape when viewed from the side, and relative vertical movement of each battery cell 63 of the battery module 60 with respect to the case 22 is suppressed. Therefore, for example, there is little risk of the connection state between the positive terminal 64 and negative terminal 65 of each battery cell 63 and the busbar becoming unstable. Furthermore, even if a large vertical impact load is applied to the case 22, there is little risk of the battery module 60 falling out of the case 22. Moreover, when the battery module 60 is assembled to the case 22 using the gripping device, it is less likely that there will be a discrepancy in the height of the upper surface of each battery cell 63. Therefore, the busbar connection work described above can be easily performed.

[0048] Furthermore, the battery module 60 can be housed inside the upper case 45 through the lower end opening 56. In this state, when the lower case 24 is connected to the lower end of the upper case 45, the battery module 60 is sandwiched vertically between the upper pressing portion 49 of the upper case 45 and the lower support portion 38 of the lower case 24. Therefore, the assembly of the battery module 60 into the case 22 is easy.

[0049] Furthermore, the upper case 45 is equipped with a pair of upper pressing portions 49 that are separated in the left-right direction, and the lower case 24 is equipped with a pair of lower support portions 38 that are separated in the left-right direction. Therefore, compared to the case where the upper case 45 has only one upper pressing portion 49 and the lower case 24 has only one lower support portion 38, positional misalignment in the height of the upper surfaces of multiple battery cells 63 is less likely to occur.

[0050] Furthermore, the lower support portion 38 of the lower case 24 is elastically deformable. Therefore, even if there are variations in the vertical dimensions of each separator 70, the battery pack 20 can suppress relative vertical movement of each battery cell 63 with respect to the case 22.

[0051] Furthermore, when the battery module 60 is supported by the lower support portion 38 of the lower case 24, the cooling air generated by the cooling fan and flowing into the internal space of the lower component 26 via the ventilation duct and front end opening 27 is prevented from leaking upward from between the lower end of the battery module 60 and the annular plane 31 by each of the lower support portions 38. As a result, the cooling air that flows into the internal space of the lower component 26 flows upward through the minute gaps between each battery cell 63 and the separator 70, the minute gaps between the end plate 85 and the battery cell 63, and the minute gaps between the end plate 97 and the battery cell 63, and is discharged to the outside of the case 22 from the upper end opening 47 of the upper case 45. As a result, each battery cell 63 can be effectively cooled by the cooling air generated by the cooling fan.

[0052] Furthermore, if an internal short circuit occurs in any of the battery cells 63, causing the exhaust valve 66 to open, the internal components (debris) of that battery cell 63 are discharged to the outside of the battery cell 63 via the exhaust valve 66. In this case, for example, the gas (smoke) contained in the internal components is smoothly discharged to the outside of the case 22 through the internal passage of the exhaust duct 58 and at least one of the front end opening and rear end opening of the exhaust duct 58.

[0053] Although the battery packs according to the embodiments have been described above, these can be modified as appropriate without departing from the spirit of the present invention.

[0054] For example, the battery pack 20 does not need to be equipped with a smoke exhaust duct 58.

[0055] Only one of the lower support portion 38 or the upper pressing portion 49 may be elastically deformable.

[0056] The lower support portion 38 may be made of rubber.

[0057] The lower support portion 38 may be manufactured as part of the lower case 24. That is, if the lower case 24 is a single-piece molded product made of die-cast aluminum, the lower support portion 38 is made of aluminum.

[0058] Furthermore, the lower case 24 may be made of resin. In this case, it is preferable that the lower case 24 has ribs to increase its mechanical strength.

[0059] The end plates 85 and 97 do not need to be in contact with the upper retaining portion 49 of the upper case 45.

[0060] The stacking direction of the battery cells 63 and separators 70 in case 22 (the extension direction of the battery module 60) may be different from the front-to-back direction.

[0061] The vehicle may be an electric vehicle that is different from an electric vehicle and is equipped with an electric motor that utilizes power from a battery pack. For example, the vehicle may be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV). [Explanation of Symbols]

[0062] 20 battery packs 22 cases 24 Lower Cases 38 Lower support part 45 Upper Case 49 Upper pressing part 56 Bottom opening 60 Battery Modules 63 battery cells 70 Separators 85 End Plate 97 End Plate

Claims

1. A battery module comprising a plurality of battery cells stacked in a predetermined stacking direction, and a plurality of separators located between two adjacent battery cells and sandwiching one of the battery cells from above and below, A case capable of housing the aforementioned battery module, Equipped with, The aforementioned case is, A lower support portion that supports the separator from below, An upper pressing portion that presses down on the separator from above, A battery pack equipped with the following features.

2. The aforementioned case is, The upper case comprises the upper retaining portion and the lower end opening located below the upper retaining portion and through which the battery module can pass, A lower case having the aforementioned lower support portion and connected to the lower end of the upper case, A battery pack according to claim 1, having the following features.

3. The battery pack according to claim 1 or 2, wherein, in a plan view, the direction perpendicular to the stacking direction is defined as the orthogonal direction, and the case comprises a pair of upper retaining portions that are separated from each other in the orthogonal direction.

4. The battery pack according to claim 1 or claim 2, wherein at least one of the upper pressing portion and the lower support portion is elastically deformable.

5. The battery module comprises a pair of end plates that are separated from each other in the stacking direction and sandwich all the battery cells and all the separators in the stacking direction, The lower support portion supports the end plate from below, The battery pack according to claim 1 or claim 2, wherein the upper pressing portion presses the end plate from above.

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