Electricity storage device

Abstract

A power storage device is provided with: a first cell stack group in which substantially rectangular parallelepiped-shaped first cell stacks having a substantially rectangular shape in plan view are stacked in the vertical direction, and a second cell stack group in which substantially rectangular parallelepiped-shaped second cell stacks having a substantially rectangular shape in plan view are stacked in the vertical direction; a second cell stack group in which substantially rectangular second cell stacks having a substantially rectangular shape in plan view are stacked in the vertical direction, the second cell stack group being disposed below the first cell stack group with a direction intersecting the longitudinal direction of the first cell stack group as the longitudinal direction; and a first frame member which is disposed between the first cell stack group and the second cell stack group, to which the first cell stack group and the second cell stack group are fixed, and which is directly or indirectly fixed to a vehicle frame.

Description

Technical Field

[0001] This disclosure relates to energy storage devices. Background Technology

[0002] Japanese Patent Application Publication No. 2013-134809 discloses a technology related to a battery pack (hereinafter referred to as a "storage device") that holds a battery module (hereinafter referred to as a "battery stack") containing multiple battery cells. In this prior art, multiple battery stacks are stacked vertically, thereby increasing the battery capacity.

[0003] However, in the aforementioned prior art, since the same battery stacks are stacked in the vertical direction, there are concerns about vibration tolerance. Summary of the Invention

[0004] This disclosure provides an energy storage device that can improve vibration resistance.

[0005] The first type of energy storage device includes: a first battery stack, in which a first battery stack of approximately rectangular parallelepiped shape that is generally rectangular in shape when viewed from above is stacked along the vertical direction; a second battery stack, in which a second battery stack of approximately rectangular parallelepiped shape that is generally rectangular in shape when viewed from above is stacked along the vertical direction, the second battery stack having a long side direction that intersects the long side direction of the first battery stack as its long side direction and being disposed below the first battery stack; and a first frame member, the first frame member being disposed between the first battery stack and the second battery stack, fixing the first battery stack and the second battery stack respectively, and being directly or indirectly fixed to the vehicle frame.

[0006] The first embodiment of the energy storage device includes a first battery stack, a second battery stack, and a first frame member. In the first battery stack, the first battery stacks, which are approximately rectangular in shape when viewed from above, are stacked vertically. In the second battery stack, the second battery stack, which is also approximately rectangular in shape when viewed from above, is stacked vertically. Furthermore, the second battery stack has its long side intersecting the long side of the first battery stack as its long side direction and is positioned below the first battery stack. The first frame member is positioned between the first and second battery stacks and fixes both the first and second battery stacks to it, and is directly or indirectly fixed to the vehicle frame.

[0007] For example, as a comparative example, when a roughly rectangular, cuboid-shaped battery stack is stacked vertically with its long sides aligned in the same direction as when viewed from above, its vibration tolerance weakens relative to the width direction of the battery stack (the direction of the short side orthogonal to the long side direction). Therefore, in the comparative example, there is concern about the vibration tolerance relative to a vibration G in a specific direction.

[0008] In contrast, in this embodiment, by directly or indirectly fixing the first and second battery stacks, which are respectively fixed in a state where their long sides intersect in the first and second battery stacks, to the vehicle frame, it is possible to change the direction of weakened vibration tolerance in the first and second battery stacks and achieve a balance between the direction of stronger vibration tolerance and the direction of weaker vibration tolerance, thereby offsetting the weaker direction. Therefore, in this embodiment, as an energy storage device, vibration tolerance can be improved, and the effects of resonance can be suppressed.

[0009] Furthermore, the term "intersecting" here has the following meanings: in addition to being perfectly orthogonal, it also includes what is called approximately orthogonal. Additionally, "directly or indirectly fixed" has the following meanings: in addition to structures that directly fix the first frame member to the vehicle frame, it also includes structures that are indirectly fixed via brackets, etc. Moreover, as for the "vehicle frame," depending on the location where the energy storage device is installed, examples include crossbeams extending along the width direction of the vehicle, longitudinal beams extending along the front-rear direction of the vehicle, etc.

[0010] Based on the first type of energy storage device, in the second type of energy storage device, in the first battery stack, a plurality of first battery cells are stacked along the long side of the first battery stack, and in the second battery stack, a plurality of second battery cells are stacked along the long side of the second battery stack.

[0011] In the second type of energy storage device, multiple first battery cells are stacked along the long side of the first battery stack in the first battery stack, and multiple second battery cells are stacked along the long side of the second battery stack in the second battery stack. That is, the direction along which the first battery cells and second battery cells are stacked is the long side direction of the first battery stack and the second battery stack.

[0012] Generally, when battery cells are stacked along a width direction orthogonal to the long side of the battery stack, i.e., when the long side of the battery stack is the same as the long side of the battery cells, the approximate central portion of the long side of the battery stack is prone to bending. In this embodiment, since the first battery cell and the second battery cell are stacked along the long side directions of the first battery stack and the second battery stack, respectively, bending of the approximate central portion of the long side directions of the first battery stack and the second battery stack can be suppressed.

[0013] Furthermore, in the first battery cell and the second battery cell, battery cells with the same structure or battery cells with different structures can be used.

[0014] Based on the first or second type of energy storage device, in the third type of energy storage device, an upper battery stack composed of the first battery stack is arranged along the vehicle width direction, a lower battery stack composed of the second battery stack is arranged along the vehicle width direction, and a plurality of the second battery stacks are arranged such that the projected size of the lower battery stack is larger than the projected size of the upper battery stack.

[0015] In the third type of energy storage device, an upper battery stack consisting of a first battery stack is arranged along the width direction of the vehicle. Additionally, a lower battery stack consisting of second battery stacks is arranged along the width direction of the vehicle. Furthermore, in the lower battery stack, multiple second battery stacks are arranged such that the projected size of the lower battery stack is larger than the projected size of the upper battery stack.

[0016] In this way, since the projected size of the lower battery stack is larger than that of the upper battery stack, the center of gravity of the energy storage device can be located on the side of the lower battery stack, which can improve the vibration stability of the energy storage device.

[0017] Based on any of the first to third forms of the energy storage device, in the fourth form of the energy storage device, the energy storage device includes a housing housing that houses the upper battery stack and the lower battery stack. The energy storage device is configured to further include: a lower housing that forms the bottom wall of the housing housing; and a second frame member that is fixed to the lower housing and disposed between the second battery stacks, with the second battery stacks respectively fixed thereon.

[0018] In the fourth type of energy storage device, a housing housing that accommodates an upper battery stack and a lower battery stack is provided. A second frame member is fixed to the lower housing, which forms the bottom wall of the housing housing. The second frame member is disposed between the second battery stacks, and the second battery stacks are respectively fixed to the second frame member.

[0019] In this configuration, since multiple second battery stacks constituting the lower battery stack are respectively fixed to a second frame member fixed to the lower housing, vibration stability in the energy storage device can be further improved.

[0020] As explained above, the energy storage device disclosed herein can improve vibration resistance. Attached Figure Description

[0021] Figure 1 This is a schematic perspective view showing the energy storage device of this embodiment.

[0022] Figure 2 It is shown schematically. Figure 1 A schematic diagram of the energy storage device shown.

[0023] Figure 3A It is shown schematically. Figure 1 The front view of the energy storage device shown.

[0024] Figure 3B It is shown schematically. Figure 1 The side view of the energy storage device shown.

[0025] Figure 4 This is a schematic diagram illustrating a comparative example. Detailed Implementation

[0026] The energy storage device according to one embodiment of the present disclosure will be described using the accompanying drawings. Furthermore, arrows UP, L, and W, appropriately shown in the figures, represent the top, long side direction, and width direction of the battery stack (first battery stack) 12 and battery stack (second battery stack) 14 constituting the energy storage device 10 of this embodiment, respectively. Additionally, the vehicle to which the energy storage device of this embodiment is applicable is an electric vehicle.

[0027] First, the structure of the energy storage device in this embodiment will be described.

[0028] like Figure 1 , Figure 2 As shown, the energy storage device 10 is configured to include multiple battery stacks 12 and 14, for example, disposed on the rear side of the vehicle. Furthermore, Figure 2 It is shown schematically. Figure 1 A schematic diagram of the energy storage device 10 is shown. (As shown) Figure 1 , Figure 2 As shown, battery stacks 12 and 14 are approximately rectangular parallelepipeds. Battery stack 12 is configured to contain multiple battery cells (first battery cells) 20, and battery stack 14 is configured to contain multiple battery cells (second battery cells) 22.

[0029] Battery cells 20 and 22 can be selected from, for example, lithium-ion secondary batteries (including liquid batteries and all-solid-state batteries), lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, cobalt-titanium lithium secondary batteries, and other secondary batteries.

[0030] Furthermore, battery cells 20 and 22 are each flattened cuboids and are stacked along the long side of the battery stacks 12 and 14, respectively. In other words, in the battery stacks 12 and 14, the direction along which battery cells 20 and 22 are stacked is the long side direction of the battery stacks 12 and 14. Additionally, rigid plate-shaped end plates 15 are provided at both ends along the long side of the battery stacks 12 and 14. Moreover, battery cells 20 and 22 can have the same structure or different structures. For example, the external dimensions of battery cells 20 and 22 can also be different.

[0031] In this embodiment, the energy storage device 10 is configured to include an upper battery stack 24 stacked in the vertical direction and disposed on the upper side of the energy storage device 10, and a lower battery stack 26 disposed on the lower side of the energy storage device 10.

[0032] The upper battery stack 24 is constructed by stacking multiple (three in this case) battery stacks 12 in a vertical direction. Furthermore, each battery stack 12 is configured such that the stacking direction of the battery cells 20 (arrow A) is the vehicle width direction (arrow W). Adjacent battery stacks 12 in the vertical direction are fixed to each other, for example, by holes (not shown) formed in end plates 15 at both ends along the long side of the battery stack 12 and by through bolts 28.

[0033] Thus, the multiple battery stacks 12 stacked in the vertical direction are referred to as battery stack group (first battery stack group) 16. That is, in this embodiment, the upper battery stack group 24 is composed of battery stack group 16.

[0034] On the other hand, in the lower battery stack 26, multiple (in this case, two) battery stacks 14 are stacked in the vertical direction. Each battery stack 14 is configured such that the stacking direction of the battery cells 22 (arrow B direction) is the vehicle's front-rear direction (arrow L direction). Furthermore, similar to the battery stack 12, adjacent battery stacks 14 in the vertical direction are fixed to each other via holes formed in end plates 15 at both ends of the long side of the battery stack 14 and through bolts 30.

[0035] Thus, the multiple battery stacks 14 stacked vertically are referred to as battery stack groups (second battery stack groups) 18. Furthermore, in this embodiment, multiple (in this case, two rows) battery stack groups 18 are arranged along the vehicle width direction in the lower battery stack group 26. That is, in this embodiment, the lower battery stack group 26 is composed of two battery stack groups 18.

[0036] Here, as Figure 3A , Figure 3BAs shown, in this embodiment, the projected dimensions (W1, L1) of the lower battery stack 26 are set to be larger than the projected dimensions (W2, L2) of the upper battery stack 24. Furthermore, W1 and W2 are the width dimensions along the vehicle width direction, and L1 and L2 are the length dimensions along the vehicle front-to-back direction.

[0037] Furthermore, in this embodiment, a plate-shaped frame member (first frame member) 32 is provided between the upper battery stack 24 and the lower battery stack 26, and the upper battery stack 24 and the lower battery stack 26 are respectively fixed to the frame member 32.

[0038] In this embodiment, the upper battery stack 24 and the lower battery stack 26 can be housed within the housing 34. The housing 34 is configured to include a lower housing 36 and an upper housing 38. The lower housing 36 is plate-shaped, and the upper battery stack 24 and the lower battery stack 26 are covered from the outside by the upper housing 38, with the frame member 32 fixed to the upper housing 38.

[0039] As an example, the upper housing 38 can be fixed to a crossbeam (vehicle frame) 35 extending along the vehicle width direction on the rear side of the upper housing 38, and the frame member 32 and the upper housing 38 can also be fastened together to the crossbeam 35. In addition, the crossbeam 35 can also be a rear crossbeam that forms part of the rear suspension structure.

[0040] On the other hand, a lower battery stack 26 is fixed to the lower housing 36. A plate-shaped frame member (second frame member) 40 is disposed between the battery stack 18 constituting the lower battery stack 26. The frame member 40 is fixed in a state in which it is erected relative to the lower housing 36 and extends along the vehicle's longitudinal direction. The front end of the frame member 40 is joined to the frame member 32, for example, by adhesive, welding, or the like.

[0041] Next, the function and effects of the energy storage device in this embodiment will be explained.

[0042] like Figure 1 , Figure 2 As shown, in this embodiment, the energy storage device 10 is configured to include an upper battery stack 24, a lower battery stack 26, and a frame member 32.

[0043] The upper battery stack 24 is configured such that the vehicle width direction (arrow W direction) is the long side direction of the upper battery stack 24, and the battery stacks 12 are stacked vertically (battery stack 16). The lower battery stack 26 is configured such that the vehicle front-to-back direction (arrow L direction) is the long side direction of the lower battery stack 26, and the battery stacks 18, which are stacked vertically, are arranged in two rows along the vehicle width direction. That is, in this embodiment, the long side direction of the battery stacks 12 constituting the upper battery stack 24 is arranged approximately orthogonally (intersecting) with the long side direction of the battery stacks 14 constituting the lower battery stack 26 in a vertically aligned manner.

[0044] For example, as a comparative example, such as Figure 4 As shown, in the energy storage device 100, when the battery stack 108 of the lower battery stack 106 and the battery stack 104 of the upper battery stack 102 are stacked vertically with their long sides in the same direction, the vibration resistance weakens relative to the width direction (the short side direction orthogonal to the long side direction) of the battery stack 104. Therefore, in the comparative example, there is concern about the vibration resistance relative to a vibration G in a specific direction. Here, since the fixing part of the lower battery stack 106 is subjected to stress, it is necessary to increase the fixing strength by adding fixing points or the like to the fixing part.

[0045] In contrast, in this embodiment, as described above, the long side direction of the battery stack 12 constituting the upper battery stack 24 is arranged approximately orthogonally to the long side direction of the battery stack 14 constituting the lower battery stack 26. Therefore, in this embodiment, a balance can be achieved between the directions of stronger and weaker vibration resistance in the upper battery stack 24 and the lower battery stack 26 by changing the direction of weakened vibration resistance, thus offsetting the weaker direction. As a result, in this embodiment, the energy storage device 10 can improve vibration resistance and suppress the effects of resonance.

[0046] In addition, generally speaking, when battery cells are stacked along a width direction orthogonal to the long side of the battery stack, the long side of the battery stack is in the same direction as the long side of the battery cells, and the approximate central part of the long side of the battery stack is prone to bending.

[0047] In contrast, in this embodiment, battery cells 20 are stacked along the long side of battery stack 12, and battery cells 22 are stacked along the long side of battery stack 14. Therefore, in this embodiment, the long side directions of battery cells 20 and 22 are different from the long side directions of battery stack 12 and battery stack 14, which can suppress the deflection of the approximate central portion of battery stack 12 and battery stack 14.

[0048] Furthermore, although not illustrated, in a battery stack, where both ends are fixed along the long side (a so-called "fixed-at-both-ends" state), the central portion along the long side may sometimes flex due to repeated vibrations caused by vehicle movement. In such cases, it is advisable to fix the central portion of the battery stack along the long side using fastening components such as bolts.

[0049] However, in this embodiment, the effects of resonance can be suppressed within the energy storage device 10, thus suppressing the deformation of the battery stacks 12 and 14 themselves. Therefore, no fastening member is needed at the central portion along the long side of the battery stacks 12 and 14 to suppress deformation. In other words, in this embodiment, the energy storage device 10, which has multiple stacked battery stacks 12 and 14, can be implemented using only the minimum necessary fastening members.

[0050] Therefore, compared with the case where the central part of the battery stacks 12 and 14 is fixed in the long side direction using fastening members, the number of components can be reduced in this embodiment. In addition, the volumetric efficiency of the battery cells 20 and 22 can be improved accordingly with the space not required to ensure the fastening members.

[0051] Furthermore, in this embodiment, in the upper battery stack 24, the battery stack 16 is arranged along the vehicle width direction, and in the lower battery stack 26, the battery stack 18 is arranged along the vehicle front-to-back direction. Moreover, in the lower battery stack 26, multiple battery stacks 18 are arranged along the vehicle width direction, such as... Figure 3A , Figure 3B As shown, the projected dimensions (W1, L1) of the lower battery stack 26 are set to be larger than the projected dimensions (W2, L2) of the upper battery stack 24.

[0052] Thus, in this embodiment, since the configuration space of the lower battery stack 26 is larger than that of the upper battery stack 24, the center of gravity of the energy storage device 10 can be located on the side of the lower battery stack 26, thereby further improving the vibration stability in the energy storage device 10.

[0053] Furthermore, in this embodiment, a housing 34 is provided to house the upper battery stack 24 and the lower battery stack 26. The bottom wall of the housing 34 is formed by a lower housing 36, and a frame member 40 is fixed to the lower housing 36. The frame member 40 is disposed between adjacent battery stacks 18 constituting the lower battery stack 26, and each battery stack 18 is fixed to the frame member 40.

[0054] Thus, in this embodiment, since multiple battery stacks 18 are respectively fixed to the frame member 40 fixed to the lower housing 36, vibration stability can be further improved in the energy storage device 10.

[0055] (Supplementary Notes to this Implementation)

[0056] In this embodiment, the following intentions are explained: Figure 1 The energy storage device 10 shown is disposed on the rear side of the vehicle, and the upper housing 38 of the energy storage device 10 (see reference) Figure 3A The energy storage device 10 is fixed to a crossbeam 35, which forms part of the vehicle frame. This crossbeam 35 is a rear crossbeam of the rear suspension structure, but the vehicle frame is not limited to this. For example, the vehicle frame could also be a rear longitudinal beam, a lower side beam, or the like, extending in the longitudinal direction of the vehicle. In this case, both ends of the energy storage device 10 in the vehicle width direction are fixed. Furthermore, the energy storage device 10 is not limited to being located at the rear of the vehicle; it could also be located at the front of the vehicle.

[0057] In this embodiment, the upper housing 38 is configured to cover the upper battery stack 24, the lower battery stack 26, and the frame member 32 from the outside, but it is not limited to this. For example, the upper housing 38 may be configured to be separated vertically by the frame member 32. Alternatively, the frame member 32 may form a floor panel, with the upper battery stack 24 disposed on the upper side of the floor panel and the lower battery stack 26 disposed on the lower side of the floor panel.

[0058] Furthermore, in this embodiment, the upper battery stack 24 is composed of a battery stack 16, which is composed of three battery stacks 12 stacked in the vertical direction. In addition, the lower battery stack 26 is composed of two battery stacks 18 arranged in the vehicle width direction, which is composed of two battery stacks 14 stacked in the vertical direction.

[0059] However, in this embodiment, as long as the long side direction of the battery stack 12 is arranged approximately orthogonally to the long side direction of the battery stack 14, the number of battery stacks 12 and 14 is not particularly limited. For example, the battery stack group 16 may consist of two battery stacks 12 stacked in the vertical direction, or the battery stack group 18 may consist of three battery stacks 14 stacked in the vertical direction.

[0060] Alternatively, for example, in the upper battery stack 24, the battery stack 16 can be arranged along the front-rear direction of the vehicle, and in the lower battery stack 26, the battery stack 18 can be arranged along the width direction of the vehicle. Moreover, in the upper battery stack 24, multiple battery stacks 16 can be arranged along the front-rear direction of the vehicle, and in the lower battery stack 26, three or more battery stacks 18 can be arranged along the width direction of the vehicle.

[0061] The above describes one embodiment of the present disclosure, but the present disclosure is not limited to such an embodiment. One embodiment and various modifications may be appropriately combined and used. Of course, it may be implemented in various forms without departing from the spirit of the present disclosure.

Claims

1. An energy storage device, wherein, The energy storage device includes: The first battery stack group, in which a first battery stack that is approximately rectangular in shape when viewed from above is stacked in the vertical direction. The second battery stack comprises a generally rectangular, cuboid-shaped battery stack stacked vertically along its length. The second battery stack has its long side intersecting the long side of the first battery stack and is positioned below the first battery stack. A first frame component is disposed between the first battery stack and the second battery stack, and the first battery stack and the second battery stack are respectively fixed thereon, and are directly or indirectly fixed to the vehicle frame.

2. The energy storage device according to claim 1, wherein, In the first battery stack, a plurality of first battery cells are stacked along the long side of the first battery stack, and in the second battery stack, a plurality of second battery cells are stacked along the long side of the second battery stack.

3. The energy storage device according to claim 1, wherein, An upper battery stack consisting of the first battery stack is arranged along the width direction of the vehicle, and a lower battery stack consisting of the second battery stack is arranged along the width direction of the vehicle. Furthermore, a plurality of the second battery stacks are arranged such that the projected size of the lower battery stack is larger than the projected size of the upper battery stack.

4. The energy storage device according to claim 3, wherein, The energy storage device includes a housing that houses the upper battery stack and the lower battery stack. The energy storage device is configured to further include: The lower housing, which forms the bottom wall portion of the receiving housing; and The second frame component is fixed to the lower housing and disposed between the second battery stacks, and the second battery stacks are respectively fixed thereon.

Images