Battery pack

Abstract

To provide a battery pack capable of effectively preventing a collision between a case and a cell module.SOLUTION: A battery pack 10 includes: two cell modules 12 that is arranged in a first direction with an intermediate space 16 interposed therebetween, in which a longitudinal direction is parallel to the first direction and a lateral direction is parallel to a second direction; a case 44 that houses the two cell modules 12 having a main wall which is a front wall 54 or a rear wall 50 located away from the two cell modules 12 in the second direction; and a reinforcement 60 having at least a first wall 62 disposed along the main wall. The reinforcement 60 overlaps the intermediate space 16 and a part of each of the two cell modules 12 in a front view.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This specification discloses a battery pack to be installed in a vehicle. [Background technology]

[0002] In recent years, electric vehicles that use a motor as one of their power sources have become widespread. Such electric vehicles are equipped with a battery pack that supplies power to the motor. A battery pack is usually configured by housing multiple cell modules and battery-related equipment in a case. Patent Document 1 discloses such a battery pack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-234870 Summary of the Invention [Problem to be solved by the invention]

[0004] Depending on the shape of the space in which the battery pack is installed, multiple cell modules may be arranged in the longitudinal direction of the cell modules. In this case, the battery pack case is elongated in one direction, which tends to reduce its rigidity. As a result, when the vehicle collides with an obstacle, there is a risk that the battery pack case will deform and collide with the cell modules.

[0005] Therefore, this specification discloses a battery pack that can effectively prevent collisions between the case and the cell modules. [Means for solving the problem]

[0006] The battery pack disclosed in this specification comprises two cell modules arranged in a first direction with an intermediate space between them, each with its longitudinal direction parallel to the first direction and its short direction parallel to a second direction; a case that houses the two cell modules, the case having a main wall that is a front wall or a rear wall positioned away from the two cell modules in the second direction; and a reinforcement having at least a first wall arranged along the main wall, wherein the reinforcement overlaps the intermediate space and a portion of each of the two cell modules when viewed from the front.

[0007] With this configuration, deformation of the case around the intermediate space is effectively suppressed, and collision between the battery case and the cell module is effectively prevented.

[0008] In this case, the case may further have a bottom wall and a top wall, and the reinforcement may further have a second wall disposed along the bottom wall or the top wall.

[0009] With this configuration, the reinforcement has a three-dimensional shape, which improves the rigidity of the reinforcement and, ultimately, the battery case, thereby more effectively preventing collisions between the battery case and the cell modules.

[0010] Furthermore, the case may further include a fastening bracket for fastening the case to the vehicle body, the fastening bracket having a portion attached to the main wall, the fastening bracket overlapping the reinforcement in a front view.

[0011] When a vehicle collides, stress tends to concentrate around the fastening bracket. With the above configuration, the battery case is reinforced around the fastening bracket, more effectively preventing deformation of the battery case. Furthermore, with the above configuration, the fastening bracket, the main wall, and the first wall overlap in the plate thickness direction, further improving the rigidity of the battery case.

[0012] The cell module may also include a stack of multiple battery cells and an end plate provided at the end of the stack on the intermediate space side, and the battery pack may include a protector interposed between the end plate and the first wall to prevent contact between the cell module and the first wall.

[0013] With this configuration, when the main wall of the battery case deforms toward the cell module, the main wall contacts the protector before the cell module does, and this contact inhibits further deformation of the main wall, effectively preventing contact between the main wall and the cell module.

[0014] In this case, the end plate may have a rib protruding toward the intermediate space, the protector may be attached to the rib, and the center of gravity of the protector may be located above the center of gravity of the cell module.

[0015] With this configuration, when the protector is pressed by the main wall, the cell module rotates in a direction away from the main wall, thereby more effectively preventing contact between the cell module and the battery case. [Effects of the Invention]

[0016] According to the technology disclosed in this specification, collisions between the case and the cell module are effectively prevented. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a perspective view of the battery pack. [Figure 2] FIG. 1 is a diagram showing the arrangement of a battery pack in a vehicle. [Figure 3] FIG. 2 is a plan view of the battery pack. [Figure 4] 4 is a cross-sectional view taken along the line AA in FIG. 3. [Figure 5] BB cross-sectional view of FIG. 3. [Figure 6] FIG. 10 is a cross-sectional view showing another example of a battery pack. DETAILED DESCRIPTION OF THE INVENTION

[0018] The configuration of the battery pack 10 will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of the battery pack 10. FIG. 2 is a diagram showing the position of the battery pack 10 in a vehicle. FIG. 3 is a plan view of the battery pack 10. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB in FIG. 3. In the following description, Fr, Up, and Rh respectively indicate the front, top, and right sides as seen by a user seated in the seat 100. In the following description, the terms front, back, left, and right generally refer to the front, back, left, and right sides as seen by a user seated in the seat 100. In addition, the case upper 52 of the battery case 44 is not shown in FIGS. 1 and 3.

[0019] The battery pack 10 shown in FIG. 1 is mounted on an electric vehicle and supplies power to a traction motor. An electric vehicle is a vehicle that has a motor as one of its power sources, such as a hybrid electric vehicle, a battery electric vehicle, or a fuel cell electric vehicle. In this example, the battery pack 10 is disposed under a seat 100 (a rear seat in the illustrated example) as shown in FIG. 2. As shown in FIG. 1, in this example, the longitudinal direction of the cell module 12 is the left-right direction of the seat 100, which is the "first direction" in the claims. Furthermore, the lateral direction of the cell module 12 is the front-rear direction of the seat 100, which is the "second direction" in the claims.

[0020] The battery pack 10 includes a battery case 44 (see FIG. 4) that houses multiple cell modules 12, one or more battery-related devices, and these. As shown in FIG. 4, the battery case 44 includes a case lower 46, a case upper 52, and a pair of side panels (not shown). The case lower 46 has a bottom wall 48 on which the cell modules 12 are placed and a rear wall 50 that stands behind the cell modules 12. The case upper 52 also has a front wall 54 that stands in front of the cell modules 12, and a top wall 56 that covers the cell modules 12 from above. The side panels cover both sides of the battery case 44 and function as side walls of the battery case 44. The rear wall 50 and the front wall 54 are located away from the cell modules 12 in the front-to-rear direction (i.e., the short direction of the cell modules 12) and correspond to the "main walls" in the claims.

[0021] The two cell modules 12 are arranged side by side in the left-right direction (i.e., the first direction) with an intermediate space 16 interposed therebetween. The cell module 12 includes a stack 13 and an end plate 39. The stack 13 is configured by stacking a plurality of battery cells 14 and a plurality of separators 15 alternately in the thickness direction. The battery cells 14 are secondary batteries capable of charging and discharging. For example, the battery cells 14 are lithium-ion secondary batteries or sodium-ion secondary batteries. The battery cells 14 may also be all-solid-state batteries. The battery cells 14 are prismatic batteries with a flat, rectangular parallelepiped shape. The plurality of battery cells 14 are electrically connected in series or in parallel by conductors called bus bars. The separators 15 are plates made of an insulating material. Grooves that function as flow paths for the flow of a cooling fluid are formed on the surface of the separators 15.

[0022] 3, an end plate 39 is disposed at one longitudinal end of the laminate 13. This end plate 39 is provided with a rib 40 that protrudes toward the intermediate space 16. As shown in FIG. 3, for example, the rib 40 protrudes from the end plate 39 and is then bent in a substantially U-shape in plan view.

[0023] An intermediate space 16 is provided between two adjacent cell modules 12. The battery pack 10 further includes one or more battery-related devices. The battery-related devices are devices necessary for safely operating the battery pack 10. For example, a battery controller, fuses 24 (see FIG. 3), ducts, a junction box, and a service plug correspond to the battery-related devices. The battery controller is a computer that controls the charging and discharging of the cell modules 12, and is an electronic device generally called an ECU (Electronic Control Unit).

[0024] The fuse 24 (see Figure 3) is an electronic component that protects the cell module 12 from overcurrent. The duct is a flow path that connects the cell module 12 with the cooling flow path and the blower. The junction box is an electronic component that unitizes relays that allow or block the flow of power. The service plug is a component that is installed at the midpoint of the power circuit and blocks high voltage when removed. Some of these battery-related devices are located in the intermediate space 16, and others are located above the cell module 12. In this example, the fuse 24 is located in the intermediate space 16.

[0025] The battery pack 10 described above is fastened to the vehicle body by a fastening bracket 66. As shown in FIG. 4, the fastening bracket 66 has a first piece 66a extending substantially vertically and a second piece 66b extending substantially horizontally from the upper end of the first piece 66a. Therefore, the fastening bracket 66 is a metal fitting having a substantially L-shape as a whole. The first piece 66a is attached to the outer surface of the rear wall 50. The second piece 66b is fastened to the vehicle body. As shown in FIG. 3, two fastening brackets 66 are provided spaced apart in the longitudinal direction. Each of the two fastening brackets 66 is attached to the rear wall 50 within the left-right range of the reinforcement 60. As a result, the rear wall 50 is sandwiched between the reinforcement 60 and the fastening bracket 66, as shown in FIG. 4.

[0026] As is clear from the above explanation, in this example, the battery pack 10 is disposed below the seat 100. Typically, the space below the seat 100 has a smaller front-to-rear dimension than its left-to-right dimension. In order to dispose the battery pack 10 in this space below the seat 100, in this example, the two cell modules 12 are aligned in the left-to-right direction with an intermediate space 16 interposed between them. With this configuration, the front-to-rear dimension of the battery pack 10 can be kept small. As a result, the battery pack 10 can be efficiently disposed in the space below the seat 100, which is elongated in the left-to-right direction.

[0027] In this example, at least some of the battery-related equipment is arranged in the intermediate space 16. With this configuration, the number of components arranged above the cell module 12 can be reduced, and the vertical dimension of the cell module 12 can be kept small.

[0028] However, when the cell modules 12 are arranged in the left-right direction, the battery case 44 naturally becomes elongated in the left-right direction, reducing its rigidity. In this case, for example, if a rear-end collision occurs in which an obstacle collides with the vehicle from behind and a forward load F1 (see FIG. 4) is input to the rear wall 50, there is a risk that the rear wall 50 will be significantly deformed. If the rear wall 50 comes into contact with the battery cells 14 or battery-related devices (e.g., fuses 24) arranged in the intermediate space 16 due to deformation, various problems will occur.

[0029] Therefore, in this example, a reinforcement 60 is disposed in the case lower 46 to suppress deformation of the battery case 44. The reinforcement 60 is a metal panel that reinforces the rear wall 50 and the bottom wall 48 of the case lower 46. As shown in FIG. 4 , the reinforcement 60 has a first wall 62 that runs along the rear wall 50 and a second wall 64 that runs along the bottom wall 48. Therefore, the reinforcement 60 has a generally L-shape as a whole. The reinforcement 60 is disposed inside the case lower 46 and is joined to the inner surface of the case lower 46.

[0030] As shown in FIG. 3 , the left-right range of the reinforcement 60 completely overlaps with and is larger than the left-right range of the intermediate space 16. Therefore, in a front view, the reinforcement 60 overlaps with a portion of each of the two cell modules 12 and the intermediate space 16. As a result, the rear wall 50 around the intermediate space 16 is reinforced by the reinforcement 60, thereby suppressing deformation of the battery case 44 even in the event of a rear-end collision. As a result, contact of the battery case 44 with the battery cells 14 and fuses 24 is effectively suppressed. Note that lines L1 and L2 in FIG. 4 are conceptual diagrams of the rear wall 50 in the event of a rear-end collision. Line L1 represents the case where the reinforcement 60 is not present, and line L2 represents the case where the reinforcement 60 is present.

[0031] In this example, the reinforcement 60 is generally L-shaped and has a first wall 62 that fits along the rear wall 50 and a second wall 64 that fits along the bottom wall 48. By making the reinforcement 60 three-dimensional rather than flat, the rigidity of the reinforcement 60 itself is improved, and deformation of the battery case 44 is more effectively prevented.

[0032] Furthermore, during a rear-end collision, part of the load F1 is transmitted to the rear wall 50 via the fastening bracket 66. Therefore, stress tends to concentrate at the contact points between the fastening bracket 66 and the rear wall 50. In this example, as described above, the fastening bracket 66 is attached to the rear wall 50 within the left-right range of the reinforcement 60. In other words, the area around the fastening bracket 66, where stress tends to concentrate, is reinforced by the reinforcement 60. This suppresses deformation around the fastening bracket 66, and effectively suppresses contact between the battery case 44 and the battery cells 14.

[0033] Furthermore, when the vehicle is running normally, vibrations Fq (see FIG. 4) of the vehicle body are transmitted to the battery case 44 via the fastening bracket 66. As described above, in this example, the periphery of the fastening bracket 66 is reinforced with the reinforcement 60, increasing rigidity. Therefore, even if vibrations Fq are input, the vibrations Fq are quickly damped. As a result, vibrations of the rear wall 50 and bottom wall 48 caused by vibrations of the vehicle body are effectively suppressed. Furthermore, vibrations of the cell module 12 caused by driving the cell module 12 are prevented from being transmitted to the vehicle body.

[0034] In this example, an end plate 39 is attached to one left-right end of the cell module 12. In this example, a protector 68 is disposed between this end plate 39 and the first wall 62. The protector 68 is a member interposed between the end plate 39 and the first wall 62 to prevent contact between them. For example, the protector 68 is a generally block-shaped member attached to a rib 40 protruding from the end plate 39. The rear end of the protector 68 is closer to the first wall 62 than the rear end of the cell module 12. Therefore, when the first wall 62 and the rear wall 50 deform forward, the first wall 62 contacts the protector 68 before the cell module 12. Furthermore, the center of gravity of the protector 68 is higher than the center of gravity of the cell module 12. Therefore, when a forward load is input to the protector 68, the cell module 12 rotates in a direction away from the first wall 62, as indicated by the two-dot chain line in FIG. 5 .

[0035] By providing such a protector 68, contact between the battery case 44 and the battery cells 14 can be more effectively prevented. That is, if the rear wall 50 and the first wall 62 deform forward in a rear-end collision, the first wall 62 will come into contact with the protector 68 before the battery cells 14. This contact suppresses further deformation of the first wall 62, effectively preventing the first wall 62 from coming into contact with the cell module 12. Furthermore, if the first wall 62 deforms further and the protector 68 is pushed forward by the first wall 62, the cell module 12 will rotate in a direction away from the first wall 62, as shown by the two-dot chain line in FIG. 5 . This more effectively prevents contact between the cell module 12 and the battery case 44.

[0036] If a load is directly transmitted to the battery cell 14 via the protector 68, the battery cell 14 may be deformed. On the other hand, in this example, the protector 68 is attached to the end plate 39 (more precisely, the rib 40). As a result, the load input to the protector 68 is not directly transmitted to the battery cell 14, and deformation of the battery cell 14 is effectively prevented.

[0037] The configurations described above are merely examples, and other configurations may be modified as appropriate as long as the configuration of claim 1 is provided. For example, the reinforcement 60 may have other configurations as long as it is arranged along the front wall 54 or the rear wall 50. For example, the reinforcement 60 may be arranged along the front wall 54 of the battery case 44. As shown in the upper part of FIG. 6, the reinforcement 60 may be flat and have only a first wall 62 that is arranged along the rear wall 50 or the front wall 54. As shown in the middle part of FIG. 6, the reinforcement 60 may be arranged outside the battery case 44 rather than inside. Furthermore, as shown in the lower part of FIG. 6, the second wall 64 of the reinforcement 60 may be arranged along the top wall 56 of the battery case 44.

[0038] In the above description, the protector 68 is attached to the end plate 39. However, the protector 68 may be attached to the first wall 62 as long as it is interposed between the end plate 39 and the first wall 62. Furthermore, the protector 68 may not be necessary.

[0039] In the above description, the seat 100 is positioned such that the front side, as seen from the occupant, faces the front of the vehicle. However, the orientation of the seat 100 may be changed as appropriate. For example, the seat 100 may be positioned such that the front side, as seen from the occupant, faces the rear or side of the vehicle. In this case, the battery pack 10 may be positioned such that its longitudinal direction faces the left-right direction of the seat 100. [Explanation of symbols]

[0040] 10 battery pack, 12 cell module, 13 laminate, 14 battery cell, 15 separator, 16 intermediate space, 24 fuse, 39 end plate, 40 rib, 44 battery case, 46 case lower, 48 bottom wall, 50 rear wall, 52 case upper, 54 front wall, 56 top wall, 60 reinforcement, 62 first wall, 64 second wall, 66 fastening bracket, 66a first piece, 66b second piece, 68 protector, 100 sheet.

Claims

1. Two cell modules arranged in a first direction with an intermediate space therebetween, each having a longitudinal direction parallel to the first direction and a lateral direction parallel to the second direction; a case for accommodating the two cell modules, the case having a main wall that is a front wall or a rear wall positioned away from the two cell modules in the second direction; a reinforcement having at least a first wall disposed along the main wall; The reinforcement overlaps the intermediate space and a portion of each of the two cell modules in a front view. An in-vehicle battery pack characterized by:

2. 2. The battery pack according to claim 1, The case further has a bottom wall and a top wall, The reinforcement further has a second wall arranged along the bottom wall or the top wall. A battery pack characterized by:

3. 2. The battery pack according to claim 1, Further, a fastening bracket for fastening the case to a vehicle body, the fastening bracket having a portion attached to the main wall, The fastening bracket overlaps the reinforcement in a front view. A battery pack characterized by:

4. 4. The battery pack according to claim 1, The cell module comprises: a stack of a plurality of battery cells; an end plate provided at an end of the stack on the intermediate space side; Equipped with the battery pack includes a protector interposed between the end plate and the first wall and preventing contact between the cell module and the first wall. A battery pack characterized by:

5. 5. The battery pack according to claim 4, The end plates have ribs that protrude toward the intermediate space, The protector is attached to the rib, The center of gravity of the protector is located above the center of gravity of the cell module. A battery pack characterized by:

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