Battery pack mounting structure, battery pack and battery pack protection structure

Abstract

To improve a natural vibration frequency of an entire structure in which a battery pack is mounted.SOLUTION: A lower case 1 has a bottom plate 1a, a side plate 1b, and a flange part 1c and houses a battery stack 2. A stack pedestal 3 connects an end of the battery pack 2 with the side plate 1b. An EA material 20 is disposed facing a surface, which is opposite to a surface connected with the stack pedestal 3, of the side plate 1b. A connection member 8 has a bottom plate 8a, a side plate 8b, and a top plate 8c and is provided so as to cover an end of the EA material 20. A bulk material 7 is inserted between the connection member 8 and the side plate. A connection member 9 connects the bottom plate 1a with the bottom plate 8a. The connection member 10 connects the flange part 1c with the top plate 8c.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack mounting structure, a battery pack, and a battery pack protection structure. [Background technology]

[0002] Hybrid and electric vehicles are equipped with battery packs containing battery stacks to supply power to the motor. Because vehicles are subject to vibrations while driving and impacts from collisions, it is necessary to prevent the battery stack from coming into contact with other components even in such cases.

[0003] For example, Patent Document 1 proposes a battery pack that can prevent a support member supporting an equipment base from coming into contact with a battery stack even in the event of a side impact. This battery pack has a structure in which a battery stack is supported by a stack base that has a deformation portion that deforms when subjected to a side impact. One end of the stack base is connected to a bottom plate of the battery pack case, and the other end is connected to a side plate of the battery pack case, with a deformation portion configured as a bending member provided between them. When a side impact is applied to the side plate of the battery pack case, the bending member that constitutes the deformation portion bends, thereby preventing the battery stack from coming into contact with the bottom plate or side plate of the battery pack case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-137537 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a structure such as that described in Patent Document 1, which uses bent members to protect the battery pack or which uses many members to support the battery stack, there is a problem in that the natural frequency of the entire structure on which the battery pack is mounted decreases.

[0006] The present disclosure has been made in consideration of such problems, and aims to improve the natural frequency of the entire structure on which the battery pack is mounted. [Means for solving the problem]

[0007] The battery pack mounting structure according to the present disclosure includes a lower case that houses a battery stack, a first bottom plate, a first side plate, and a flange portion extending from the first side plate, a stack base that connects an end of the battery stack to the first side plate, an energy absorbing material arranged facing a second surface opposite to a first surface of the first side plate to which the stack base is connected, a second bottom plate, a top plate, and a second side plate that connects ends of the second bottom plate and the top plate on the second surface side, a first connecting member that is arranged to cover the end of the energy absorbing material on the second surface side, a bulk material inserted between the first connecting member and the second surface, a second connecting member that connects the first bottom plate and the second bottom plate, and a third connecting member that connects the flange portion to the top plate.

[0008] The battery pack according to the present disclosure has a battery stack, a first bottom plate, a first side plate, and a flange portion extending from the first side plate, and is equipped with a lower case that houses the battery stack, and a stack base that connects an end of the battery stack to the first side plate, wherein an energy absorbing material is arranged to face a second surface opposite to a first surface of the first side plate to which the stack base is connected, a second bottom plate, a top plate, and a second side plate that connects the ends of the second bottom plate and the top plate on the second surface side, wherein a first connecting member is arranged to cover the end of the energy absorbing material on the second surface side, a bulk material is inserted between the first connecting member and the second surface, a second connecting member is arranged to connect the first bottom plate and the second bottom plate, and a third connecting member is arranged to connect the flange portion to the top plate.

[0009] The protective structure for a battery pack according to the present disclosure includes an energy absorbing material, a second bottom plate, a top plate, and a second side plate connecting ends of the second bottom plate and the top plate, and further includes a first connecting member provided to cover the end of the energy absorbing material, a bulk material arranged with one end facing the energy absorbing material across the second side plate, a second connecting member one end of which is connected to the second bottom plate, and a third connecting member one end of which is connected to the top plate, A battery stack is housed in a lower case having a first bottom plate, a first side plate, and a flange portion extending from the first side plate, a stack base connects an end of the battery stack to the first side plate, the other end of the bulk material faces a second surface opposite to a first surface of the first side plate to which the stack base is connected, the other end of the second connecting member is connected to the first bottom plate, and the other end of the third connecting member is connected to the flange portion.

[0010] With the above configuration, the load path from the energy absorber to the battery stack via the first side plate and stack base can be arranged in a straight line, reducing the bending of the load path in the vertical direction, thereby improving the natural vibration value of the battery pack mounting structure.

[0011] This makes it possible to improve the natural frequency of the entire structure in which the battery pack is mounted. [Effects of the Invention]

[0012] According to the battery pack mounting structure, battery pack, and battery pack protection structure of the present disclosure, the natural frequency of the entire structure mounting the battery pack can be improved. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view of a typical battery pack mounting structure. [Figure 2] FIG. 1 is an enlarged cross-sectional view of a typical battery pack mounting structure. [Figure 3] 1 is a top view of a battery pack mounting structure according to a first embodiment. [Figure 4] 4 is a cross-sectional view of the battery pack mounting structure taken along the line AA in FIG. 3. [Figure 5] 4 is an enlarged cross-sectional view of the battery pack mounting structure taken along the line AA in FIG. 3. [Figure 6] 2 is a diagram showing a load path in the AA cross section of the battery pack mounting structure according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, the present embodiment will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiment. In addition, the following description and drawings have been simplified appropriately for clarity of explanation.

[0015] [General battery pack] As a premise for understanding the configuration of the battery pack mounting structure according to this embodiment, the configuration of a general battery pack mounting structure and its problems will first be described. A battery pack is configured to be mounted on a vehicle or the like to supply power to drive a motor. FIG. 1 is a cross-sectional view of a general battery pack mounting structure 9000. The general battery pack mounting structure 9000 includes a battery pack 900 and a battery pack protective structure 910 that protects the battery pack 900 from loads such as impacts. The battery pack 900 has a lower case 91, a battery stack 92, a stack base 93, a stack bracket 94, and an upper case 95. The battery pack protective structure 910 includes an energy absorption material (hereinafter referred to as EA material) 20.

[0016] 1, when battery pack 900 is mounted on a vehicle, the X direction, which is the horizontal direction from left to right on the page, is the width direction of the vehicle, the Z direction, which is the vertical direction from bottom to top on the page, is the height direction of the vehicle, and the Y direction, which is the normal direction from the front to the back of the page, is the front-to-rear direction of the vehicle. Note that, hereinafter, the side toward which the X direction arrow points is referred to as the +X side, and the opposite side is referred to as the -X side. The side toward which the Y direction arrow points is referred to as the +Y side, and the opposite side is referred to as the -Y side. The side toward which the Z direction arrow points is referred to as the +Z side, and the opposite side is referred to as the -Z side.

[0017] Although not shown, in the battery pack 900, a plurality of battery stacks 92 extending in the X direction are arranged side by side in the Y direction inside a box-shaped lower case 91 having a bottom plate along the XY plane.

[0018] A typical battery pack mounting structure 9000 has a bilaterally symmetrical configuration. As described above, the battery pack 900 has a lower case 91, a battery stack 92, a stack base 93, a stack bracket 94, and an upper case 95. The battery pack 900 has a bilaterally symmetrical configuration in a cross-sectional view. The lower case 91 is a box-shaped member having a bottom plate extending in the X direction, and the battery stack 92, the stack base 93, and the stack bracket 94 are housed in the lower case 91. The +Z side of the lower case 91 is covered by the upper case 95.

[0019] The configuration of a general battery pack mounting structure 9000 will be described below with reference to an enlarged cross-sectional view. Figure 2 is an enlarged cross-sectional view of the -X side of the general battery pack mounting structure 9000.

[0020] The lower case 91 is a member that connects a bottom plate 91a, which is a plate-like member extending in the -X direction, to a side plate 91b extending in the +Z direction, and further to a flange portion 91c extending in the -X direction.

[0021] The battery stack 92 is disposed on the +Z side of the bottom plate 91a. The battery stack 92 has a plurality of battery cells 92a and two end plates 92b. The plurality of battery cells 92a are stacked in the X direction. Although not shown, the plurality of battery cells 92a are electrically connected to each other via connection means. End plates 92b are disposed on both ends of the stack of the plurality of battery cells 92a, i.e., on the +X side end and the -X side end. In other words, in the X direction, the stack of the plurality of battery cells 92a is disposed so as to be sandwiched between the two end plates 92b.

[0022] The stack base 93 is a component arranged inside the box-shape of the lower case 91, i.e., between the inner surface of the lower case 91 and the battery stack 92. In the cross section shown in FIG. 2 , the stack base 93 is a component that connects a flat bottom plate 93a extending in the −X direction to a side plate 93b extending in the +Z direction, and further to a connecting portion 93c extending in the −X direction. The bottom plate 93a is arranged above the bottom plate 91a, i.e., on the +Z side, and the bottom plate 93a and bottom plate 91a are connected by joining or fastening. Hereinafter, locations where multiple components are joined are indicated by thick dashed lines.

[0023] The stack bracket 94 connects the stack base 93 and an end plate 92b of the battery stack 92, and supports the battery stack 92 above the bottom plate 91a of the lower case 91. The stack bracket 94 is a member that connects a connecting portion 94a extending in the +X direction to a support plate 94b extending in the +Z direction. The connecting portion 94a is positioned on the +Z side of the connecting portion 93c, and the connecting portion 94a and the connecting portion 93c are connected by joining or fastening. The support plate 94b is connected to the end plate 92b by joining or fastening.

[0024] Upper case 95 is a member that connects flange portion 95a, which is a plate-like member extending in the +X direction, to side plate 95b extending in the +Z direction, and further to top plate 95c extending in the +X direction. Flange portion 95a is disposed on the +Z side of flange portion 91c, and flange portion 95a and flange portion 91c are connected by bonding or fastening. Note that a spacer 96, for example, may be inserted into the gap on the +X side of the connecting portion between flange portion 95a and flange portion 91c to support flange portion 95a and flange portion 91c.

[0025] On the outer surface of the side plate 91b of the lower case 91, that is, on the surface on the -X side, an EA material 20 is arranged to absorb a load such as an impact in the horizontal direction, that is, in the X direction.

[0026] As described above, the general battery pack mounting structure 9000 has a bilaterally symmetrical configuration in a cross-sectional view, and the +X side of the general battery pack mounting structure 9000 is symmetrical to the -X side. Therefore, a description of the configuration of the +X side of the general battery pack mounting structure 9000 in a cross-sectional view will be omitted.

[0027] As described above, in this configuration, both ends of the battery stack 92 in the X direction are supported by the stack base 93 and the stack bracket 94. Furthermore, by arranging the EA material 20 on both sides of the lower case 91 in the X direction, the battery stack 92 is protected from loads such as impacts in the X direction.

[0028] Next, we will consider the load path, which is the path along which a load is applied in the width direction of the vehicle, i.e., the X direction. Load F is transmitted from the EA member 20 to the battery stack 92 via the connecting parts of the battery pack 900 components. In FIG. 2, load F is transmitted from the EA member 20 to the lower case 91, and then from the lower case 91 to the connecting part between the lower case 91 and stack base 93, via the side plate 93b, the connecting part between the stack base 93 and stack bracket 94, and via the support plate 94b, to the upper side of the end plate 92b. Load F is then transmitted from the end plate 92b to the stack of battery cells 92a.

[0029] In this way, the load path in the X direction in the EA material 20 and the battery pack 900 becomes a meandering path up and down, and therefore the load path of the up and down vibration of the EA material 20 and the battery pack 900 is divided.

[0030] If the load path of the vertical vibration is interrupted, the natural vibration value of the battery pack mounting structure will decrease, leading to the occurrence of resonance phenomena when the vehicle is in operation.

[0031] Therefore, in this embodiment, a battery pack that can suppress meandering of the load path and improve the natural vibration value of the battery pack mounting structure will be described.

[0032] Embodiment 1 [Battery pack according to the first embodiment] 3 is a top view of the battery pack mounting structure 1000 according to the first embodiment. The X direction, which is the horizontal direction from left to right on the page, is the width direction of the vehicle, the Y direction, which is the vertical direction from bottom to top on the page, is the front-to-rear direction of the vehicle, and the Z direction, which is the normal direction from the back to the front of the page, is the height direction of the vehicle.

[0033] In the battery pack mounting structure 1000, a plurality of battery stacks 2 extending in the X direction are arranged side by side in the Y direction inside a box-shaped lower case 1 having a bottom plate along the XY plane. Fig. 3 shows an example in which four battery stacks 2 are arranged in the Y direction. Note that Fig. 3 is simplified to make it easier to understand the relationship between the lower case 1 and the battery stacks 2, and other components such as electrical wiring connected to each battery stack 2, fixing members for the battery stacks 2, and members for fixing the lower case are omitted as appropriate. Furthermore, the upper side of the battery stack 2, i.e., the +Z side, is covered by an upper case, but is not shown in Fig. 3 for simplification.

[0034] 4 is a cross-sectional view of the battery pack mounting structure 1000 taken along the AA cross section of FIG. 3. The AA cross section is a ZX cross section passing through the center of the battery stack 2. The directions in FIG. 3 are the same as those in FIGS.

[0035] The battery pack mounting structure 1000 includes a battery pack 100 and a battery pack protective structure 110 that protects the battery pack 100 from loads such as impacts. The battery pack 100 has a lower case 1, a battery stack 2, a stack base 3, fastening members 4, and an upper case 5. The battery pack protective structure 110 has a bulk material 7, connecting members 8 to 10, and an EA material 20.

[0036] The battery pack mounting structure 1000 has a bilaterally symmetrical configuration in the AA cross section. In Fig. 4, the lower case 1 is a box-shaped member having a bottom plate extending in the X direction, and the battery stack 2, stack base 3, and fastening members 4 are housed inside the lower case 1. The +Z side of the lower case 1 is covered with the upper case 5.

[0037] The configuration of the battery pack mounting structure 1000 will be described below with reference to enlarged cross-sectional views. Fig. 5 is an enlarged cross-sectional view of the -X side of the battery pack mounting structure 1000 in the AA cross section of Fig. 3 .

[0038] The lower case 1 is a member that connects a bottom plate 1a, which is a plate-like member extending in the -X direction, to a side plate 1b extending in the +Z direction, and further to a flange portion 1c extending in the -X direction. The bottom plate 1a is also referred to as the first bottom plate, and the side plate 1b is also referred to as the first side plate.

[0039] The battery stack 2 is arranged on the +Z side of the bottom plate 1a. The battery stack 2 has a plurality of battery cells 2a and two end plates 2b. The plurality of battery cells 2a are stacked in the X direction. Although not shown, the plurality of battery cells 2a are electrically connected to each other via connection means. End plates 2b are arranged on both ends of the stack of the plurality of battery cells 2a, i.e., on the +X side end and the -X side end. In other words, in the X direction, the stack of the plurality of battery cells 2a is arranged so as to be sandwiched between the two end plates 2b.

[0040] The stack base 3 is a component arranged inside the box-shaped lower case 1, i.e., between the inner surface of the lower case 1 and the battery stack 2. The stack base 3 is a component in which the side plate 3a extends on the -Z side along the inner surface of the side plate 1b and connects to the connecting portion 3b extending in the +X direction. The side plate 3a and the side plate 1b are connected by bonding or fastening. The inner surface of the side plate 1b to which the side plate 3a is connected is also referred to as the first surface.

[0041] The end plate 2b is disposed above the connecting portion 3b of the stack base 3, and is connected to the end plate 2b and the connecting portion 3b by a fastening member 4 that is inserted in the Z direction between the end plate 2b and the connecting portion 3b. The fastening member 4 can be any of various fastening means, such as a screw or a combination of a nut and a bolt.

[0042] The upper case 5 is a member that connects a flange portion 5a, which is a plate-like member extending in the +X direction, to a side plate 5b extending in the +Z direction, and further to a top plate 5c extending in the +X direction. The flange portion 5a is disposed on the +Z side of the flange portion 1c, and the flange portion 5a and the flange portion 1c are connected by joining or fastening. Note that a spacer 6, for example, may be inserted into the gap on the +X side of the connecting portion between the flange portion 5a and the flange portion 1c to support the flange portion 5a and the flange portion 1c.

[0043] An EA material 20 is arranged on the outer surface of the side plate 1b of the lower case 1, i.e., the -X side surface, via a bulk material 7 and a connecting member 8 that transmit loads such as impacts in the horizontal direction, i.e., the X direction. The outer surface of the side plate 1b of the lower case 1 is also referred to as the second surface.

[0044] The connecting member 8 is a member that connects the bottom plate 8a extending in the +X direction to the side plate 8b extending in the +Z direction, and further to the top plate 8c extending in the -X direction, and is fitted into the +X side end of the EA material 20.

[0045] The bulk material 7 is inserted between the side plate 1b and the side plate 8b, and transmits the load from the EA material 20 to the side plate 1b. The bottom plate 8a is also called a second bottom plate, and the side plate 8b is also called a second side plate.

[0046] A connecting member 9, which is a plate-like member extending in the X direction, is disposed on the -Z side of the bottom plate 1a of the lower case 1 and the bottom plate 8a of the connecting member 8. The bottom plate 1a and the connecting member 9 are connected by fastening or joining. The bottom plate 8a and the connecting member 9 are connected by fastening or joining.

[0047] A connecting member 10 is disposed on the +Z side of the flange portion 5a of the upper case 5 and the top plate 8c of the connecting member 8. The connecting member 10 is a member that connects from a connecting portion 10a, which is a plate-shaped member that extends in the -X direction while contacting the flange portion 5a, to a connecting portion 10c, which is a plate-shaped member that extends in the -X direction while contacting the top plate 8c, via a connecting portion 10b that extends in the -Z direction. The flange portion 1c, the flange portion 5a, and the connecting portion 10a are connected by fastening or bonding. The connecting portion 10c, the top plate 8c, and the EA material 20 are connected by fastening or bonding.

[0048] As described above, the battery pack mounting structure 1000 has a symmetrical configuration in the AA cross section, and the +X side of the battery pack mounting structure 1000 is symmetrical to the -X side. Therefore, a description of the configuration of the +X side of the battery pack mounting structure 1000 in the AA cross section will be omitted.

[0049] In this configuration, the EA material 20 is also disposed on both sides of the lower case 1 in the X direction, so that the battery stack 2 is protected from loads such as impacts in the X direction.

[0050] Next, we consider the load path, which is the path along which the load is applied in the width direction of the vehicle, that is, the X direction.

[0051] 6 is a diagram showing the load path at the AA cross section of the battery pack mounting structure 1000. At the AA cross section, the load F is transmitted from the EA material 20, via the bulk material 7, to the side plate 1b of the lower case 1, and then from the side plate 1b, via the connection between the side plate 1b and the stack base 3, the stack base 3, and the fastening structure between the stack base 3 and the end plate 2b using the fastening member 4, to the stack of battery cells 2a.

[0052] In this case, the path of the load F, i.e., the load path, runs in the +X direction from the EA material 20 to the connection between the stack base 3 and the end plate, then runs in the +Z direction, and then runs again in the X direction to enter the stack of battery cells 2a.

[0053] Therefore, compared to the load path in the AA cross section of the general battery pack mounting structure 9000 shown in FIG. 2, the bending of the load path in the up and down direction can be significantly reduced.

[0054] As described above, with this configuration, the load path from the EA material 20 to the battery stack 2 via the side plate 1b of the lower case 1 and the stack base 3 is arranged in a straight line, thereby reducing the bending of the load path in the vertical direction. As a result, it is possible to prevent vertical displacement of the battery pack and the internal components of the battery protective structure, as well as relative displacement between the battery pack and the battery protective structure. This makes it possible to improve the natural vibration value of the entire battery pack mounting structure consisting of the battery pack 100 and the EA material 20.

[0055] Other embodiments The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, in the battery pack 100 according to the above-described embodiment, four battery stacks 2 are arranged in the Y direction, but this is merely an example. In the battery pack, any number of battery stacks 2 greater than or equal to two may be arranged in the Y direction.

[0056] The shapes of the components constituting the battery pack mounting structure 1000 are not limited to those described in the above embodiments, and other shapes are also possible as long as they can perform the same functions. [Explanation of symbols]

[0057] 1, 91 Lower case 1a, 91a bottom plate 1b, 91b side plate 1c, 91c flange 2, 92 battery stack 2a, 92a battery cells 2b, 92b end plates 3, 93 stack base 3a, 93a side plate 3b, 93b connection part 4 Fastening members 5, 95 upper case 5a, 95a flange 5b, 95b side plate 5c, 95c top plate 6, 96 spacer 7 Bulk materials 8~10 Connecting members 8a bottom plate 8b side plate 8c Top 10a, 10c, 93c, 4a connection part 10b Liaison Department 20 EA material 94 Stack Bracket 94b Support plate 100, 900 battery pack 110, 910 Battery pack protection structure 1000, 9000 battery pack mounting structure

Claims

1. A battery pack; a battery pack protection structure for protecting the battery pack, The battery pack A battery stack; a lower case that houses the battery stack and has a first bottom plate, a first side plate, and a flange portion extending from the first side plate; a stack base that connects an end of the battery stack and the first side plate, The battery pack protective structure includes: an energy absorbing material disposed opposite to a second surface of the first side plate opposite to a first surface to which the stack base is connected; a first connecting member including a second bottom plate, a top plate, and a second side plate connecting end portions of the second bottom plate and the top plate on the second surface side, the first connecting member being provided to cover the end portion of the energy absorbing material on the second surface side; a bulk material inserted between the first connecting member and the second surface; a second connecting member that connects the first bottom plate and the second bottom plate; and a third connecting member that connects the flange portion and the top plate. Battery pack mounting structure.

2. The stack base has a third side plate connected to the first side plate and a connecting portion extending from the third side plate; the connecting portion of the stack base and a lower end of the end of the battery stack are connected by a fixing member that extends in a direction perpendicular to the first bottom plate and is inserted through the connecting portion of the stack base and the end of the battery stack. The battery pack mounting structure according to claim 1 .

3. a connection portion between the connection portion of the stack base and an end portion of the battery stack, a connection portion between the stack base and the first surface, the bulk material, the second side plate, and the energy absorbing material are arranged side by side in a predetermined direction. The battery pack mounting structure according to claim 2 .

4. A battery pack protected by a battery pack protective structure having an energy absorbing material, a bulk material, and first to third connecting members, A battery stack; a lower case that houses the battery stack and has a first bottom plate, a first side plate, and a flange portion extending from the first side plate; a stack base that connects an end of the battery stack and the first side plate, the energy absorbing material is disposed so as to face a second surface of the first side plate opposite to a first surface to which the stack base is connected, the first connecting member has a second bottom plate, a top plate, and a second side plate connecting end portions of the second bottom plate and the top plate on the second surface side, and is arranged to cover the end portion of the energy absorbing material on the second surface side; the bulk material is inserted between the first connecting member and the second surface; the second connecting member is arranged to connect the first bottom plate and the second bottom plate, The third connecting member is arranged to connect the flange portion and the top plate. Battery pack.

5. A battery pack protection structure for protecting a battery pack having a battery stack, a lower case, and a stack base, An energy absorber; a first connecting member including a second bottom plate, a top plate, and a second side plate connecting ends of the second bottom plate and the top plate, the first connecting member being provided to cover an end of the energy absorbing material; a bulk material having one end facing the energy absorbing material across the second side plate; a second connecting member having one end connected to the second bottom plate; a third connecting member, one end of which is connected to the top plate; the battery stack is housed in a lower case having a first bottom plate, a first side plate, and a flange portion extending from the first side plate; the stack base connects an end of the battery stack to the first side plate, the other end of the bulk material faces a second surface of the first side plate opposite to a first surface to which the stack base is connected, the other end of the second connecting member is connected to the first bottom plate, The other end of the third connecting member is connected to the flange portion. Battery pack protective structure.

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