JP7461722B2 - Power Supplies - Google Patents

Description

The present invention relates to a power supply device.

Power supply devices such as battery packs are used as power sources for power-assisted bicycles, electric motorcycles, power tools, electric cleaners, and the like. Power supply devices aim to achieve high output and high capacity by arranging a large number of secondary battery cells and connecting them in series or parallel. Each secondary battery cell has a safety valve on one end face of the cylindrical outer can, for example on the positive electrode side, to release high-pressure, high-temperature gas outside the cell if some abnormality occurs inside the cell. The safety valve detects when the outer can becomes high pressure and opens, releasing the high-pressure, high-temperature gas inside the outer can to the outside of the cell.

In order to meet the recent demand for higher output, power supply devices that combine multiple battery blocks, each of which has multiple secondary battery cells arranged in a row, are being used. For example, a structure in which multiple battery blocks 940A, 940B are connected is used, as in the power supply device 900 shown in the exploded perspective view of Figure 14. In the case of such a structure, among the end faces of the secondary battery cells that have safety valves, those located on the front side of the power supply device 900 can be discharged to the outside relatively smoothly even if the safety valve is opened.

However, in cases where the end face of the secondary battery cell with the safety valve is located on the inside of the power supply device, i.e., on the side where the battery blocks are connected to each other, the high-temperature, high-pressure gas discharged from the safety valve has nowhere to go and may be released in an unintended direction. In particular, since a battery block connects multiple secondary battery cells in series or parallel, it can be difficult to concentrate the faces with safety valves on a specific side, and in configurations where multiple battery blocks are connected to each other, it is difficult to avoid the occurrence of secondary battery cells with the face with the safety valve located on the connecting side, and it has generally been difficult to create a configuration that prevents the discharge of high-pressure gas at this interface.

JP 2008-251472 A JP 2008-251470 A

One of the objectives of the present invention is to provide a power supply device that enhances safety by regulating the direction of gas discharge even if the safety valve of a battery cell is opened.

a first end face of the battery block that holds the first and second battery cells in a parallel position with the first end face being flush with the first outer can; and a separator plate arranged between the first and second battery blocks, wherein the first and second battery blocks are spaced apart with an insulating space between them, and at least one of the battery cells included in opposing battery blocks is arranged with the exhaust valves facing each other across the insulating space, and at least one surface of the separator plate has a gas exhaust direction regulating wall that defines a gas exhaust path that guides gas released when the exhaust valve is opened in a predetermined direction, the gas exhaust direction regulating wall being formed as a convex stripe so as to partially provide a space in the extension direction , and the gas exhaust direction regulating wall is formed integrally on both sides of the separator, and a heat absorption sheet is arranged on the end faces of the first and second battery cells.

With the above configuration, even if the internal pressure of any of the battery cells rises and gas is discharged, the direction of the gas discharge can be controlled by the gas discharge direction control wall provided on the separator, so safety can be increased by designing it so that gas is not sprayed onto undesirable areas.

1 is a vertical cross-sectional view showing a power supply device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a battery assembly of the power supply device of FIG. 1 . FIG. 3 is an exploded perspective view of the battery assembly of FIG. 2 . FIG. 4 is a further exploded perspective view of the battery assembly of FIG. 3 . FIG. 4 is a side view of one of the battery blocks in FIG. 3 . 6 is a vertical cross-sectional view of the battery block of FIG. 5 taken along line VI-VI. 7 is a vertical cross-sectional view of the battery block of FIG. 5 taken along line VII-VII. FIG. 7 is an enlarged cross-sectional view of a main portion of FIG. 6 . 4 is a perspective view showing a state in which a separator is attached to one of the battery blocks in FIG. 3. FIG. FIG. 10 is a perspective view showing a state in which a separator plate is removed from FIG. 9 . FIG. FIG. 11 is a plan view of a separator of a power supply device according to a second embodiment. FIG. 11 is a plan view of a separator of a power supply device according to a third embodiment. FIG. 13 is an exploded perspective view showing a conventional power supply device. FIG. 4 is an exploded perspective view showing how exhaust spaces are formed between battery blocks.

In addition to the above configuration, a power supply device according to one embodiment of the present invention may be configured as follows. The gas discharge direction control wall is provided on the separator in an area where one end face of the battery cells is adjacent to each other. With the above configuration, even if gas is discharged from one battery cell, the gas discharge direction control wall interposed between the end faces prevents the gas from heating the exhaust valve of the adjacent battery cell, thereby improving safety.

The gas discharge direction control walls can be formed on both sides of the separator. With the above configuration, the gas discharge direction control walls of the separator interposed between the battery blocks can control the gas discharge direction for the battery cells arranged on both sides of the separator, further enhancing safety.

The gas discharge direction control wall can be formed integrally with the separator plate.

The gas discharge direction control wall can be made of glass fiber reinforced PBT.

The separator can be made of mica, glass epoxy or aluminum.

The gas discharge direction control wall can be formed in a straight line extending vertically.

The gas discharge direction control wall can also be formed in a straight line extending horizontally.

Furthermore, the gas discharge direction control wall may be formed in a curved shape.

The power supply device may further include an exterior case that houses the plurality of battery blocks.

The following describes the embodiments of the present invention based on the drawings. However, the embodiments shown below are merely examples of configurations for embodying the technical ideas of the present invention, and the present invention is not limited to the following. In addition, the members shown in the claims are in no way specified as members of the embodiments. In particular, the dimensions, materials, shapes, and relative positions of the components described in the embodiments are merely explanatory examples, and are not intended to limit the scope of the present invention, unless otherwise specified. The sizes and positional relationships of the components shown in each drawing may be exaggerated to clarify the explanation. Furthermore, in the following explanation, the same names and symbols indicate the same or similar components, and detailed explanations will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured with the same material so that multiple elements are shared by one material, or conversely, the function of one material may be shared by multiple materials. In addition, the contents described in some examples and embodiments may be applicable to other examples and embodiments.

The power supply device described below will be described as being applied mainly as a driving power source for electric vehicles such as electric scooters, electric carts, and electric cars that run only on a motor. The power supply device of the present invention may also be used in hybrid cars that run on both an engine and a motor, or in applications other than electric vehicles that require high output, such as home and factory power storage devices.
[Embodiment 1]

A power supply device according to the first embodiment is shown in Figs. 1 to 8. In these figures, Fig. 1 is a vertical cross-sectional view showing a power supply device 100 according to one embodiment of the present invention, Fig. 2 is a perspective view showing a battery assembly 40 of the power supply device 100 in Fig. 1, Fig. 3 is an exploded perspective view of the battery assembly 40 in Fig. 2, Fig. 4 is a further exploded perspective view of the battery assembly 40 in Fig. 3, Fig. 5 is a side view of the battery block 40A in Fig. 3, Fig. 6 is a vertical cross-sectional view taken along line VI-VI of the battery block 40A in Fig. 5, Fig. 7 is a vertical cross-sectional view taken along line VII-VII of the battery block 40A in Fig. 5, and Fig. 8 is an enlarged cross-sectional view of a main part of Fig. 6. The power supply device 100 shown in these figures has a battery assembly 40 built into an exterior case 9. The battery assembly 40 is covered on one side with an insulating plate 4 as shown in Figs. 2, 3, 4, etc. The battery assembly 40 comprises a pair of battery blocks 40A, 40B, which are connected by being arranged in opposing positions (left and right in Fig. 1). A separator 64 is arranged between the battery blocks 40A, 40B as shown in Fig. 3. Furthermore, a heat absorbing sheet 68 is arranged between the separator 64 and the battery blocks 40A, 40B as shown in the exploded perspective view of Fig. 4. In addition, a circuit board 8 is arranged on the top surface of the battery assembly 40, on which a charge/discharge circuit for controlling the charging and discharging of the battery cells 1, a protection circuit, and the like are mounted.
(Battery blocks 40A, 40B)

As shown in Figures 1 to 7, each battery block 40A, 40B has multiple battery cells 1 arranged in a parallel position with both ends on the same plane, and lead plates 45 connected to end electrodes 13 at both ends. The battery assembly 40 has a pair of opposing battery blocks 40A, 40B arranged side by side in the axial direction of the battery cells 1, and an insulating space 6 is provided between the pair of battery blocks 40A, 40B. As shown in Figure 5 and other figures, the lead plates 45 are current collecting terminals made of a metal plate or the like. As shown in the enlarged cross-sectional view of Figure 8, each battery block 40A, 40B has end electrodes 13 arranged opposite each other across the insulating space 6.
(Battery cell 1)

As shown in the enlarged cross-sectional view of FIG. 8, the battery cell 1 has an outlet of the exhaust valve 2, which opens at a set pressure, on its end surface. The battery cell 1 has end electrodes 13 on both ends. This battery cell 1 has an opening of a metal exterior can made of aluminum or the like that is airtightly sealed with a sealing plate, a protruding electrode is provided on the sealing plate to serve as the first end electrode 13A, and the bottom surface of the exterior can serves as the second end electrode 13B. The outlet of the exhaust valve 2 is provided on the protruding electrode side or on the bottom surface of the exterior can.

The battery cells 1 are cylindrical lithium ion batteries. Lithium ion batteries have a large capacity relative to their size and weight, allowing the total capacity of the power supply device to be large. However, the power supply device of the present invention does not specify that the battery cells be lithium ion batteries. Other rechargeable secondary batteries can be used for the battery cells. Also, while the power supply device 100 in FIG. 1 uses cylindrical batteries as the battery cells, rectangular batteries can also be used for the battery cells. Lead plates 45 are welded to the end electrodes 13 at both ends of each battery cell 1, connecting adjacent battery cells 1 in series or parallel.
(Battery holder 44)

Battery blocks 40A and 40B each have a battery holder 44 that holds multiple battery cells 1 with their outer casings parallel to one another and one end surface flush with one another. As shown in Figs. 4 and 7, the battery holder 44 positions the battery cells 1 in fixed positions. The battery holder 44 is made by molding an insulating material such as plastic. The battery holder 44 in the figure positions all the battery cells 1 in fixed positions in a parallel orientation. The battery cells 1 that are positioned in fixed positions by the battery holder 44 have lead plates 45 welded to both ends, so that the lead plates 45 welded to each end are positioned on the same plane, and each battery cell 1 is positioned in the battery holder 44 so that both ends are positioned approximately on the same plane.

The battery holder 44 has an insertion section 44A into which the battery cell 1 is inserted and positioned in a fixed position. In the power supply devices 100 shown in Figures 4, 6, 7, etc., the battery cells 1 are cylindrical batteries, so the insertion section 44A is cylindrical. The battery holder 44 is made of plastic molded into a tube shape, with the insertion section 44A provided on the inside. The insertion section 44A has openings 44B on both ends that expose the battery ends. The openings 44B expose the ends of the battery cells 1 inserted into the insertion section 44A to the outside from the insertion section 44A. The end faces of the battery cells 1 exposed in the openings 44B become end electrodes 13, to which lead plates 45 are welded and fixed.
(insulation space 6)

As shown in Figure 1, an insulating space 6 is provided between a pair of battery blocks 40A, 40B, and a battery assembly 40 in which end faces of battery cells 1 are arranged on both sides of the insulating space 6 has the exhaust outlet of the exhaust valve 2 positioned facing the insulating space 6. When the exhaust valve 2 opens, high-temperature gas is exhausted from the exhaust outlet and sprayed toward the end faces of the opposing battery blocks 40A, 40B. The high-temperature gas sprayed onto the opposing faces of the opposing battery cells 1 can induce thermal runaway in the battery cells 1. The power supply device 100 in Figures 4 and 6 has a separator 64 positioned in the middle of the insulating space 6.
(Isolation plate 64)

The separator 64 is a heat-resistant insulating sheet that has a heat-resistant temperature, i.e., a melting point, that is not melted by the gas emitted from the exhaust valve 2. For example, heat-resistant paper that has been flame-retardant can be used as the insulating sheet. However, instead of heat-resistant paper, the separator 64 can also be made of paper or nonwoven fabric in which inorganic fibers that are not melted by the gas emitted are gathered in a sheet form, or an inorganic sheet in which inorganic materials are bonded in a thin sheet form. These separators 64 can be made thin, so that the separator 64 can widen the insulating space 6 and smoothly exhaust the gas emitted without reducing the actual volume of the insulating space 6. The insulating separator 64 can insulate the end faces and lead plates 45 of the battery cells 1 that are arranged on both sides. However, the material that constitutes the separator does not necessarily have to be an insulating material. For example, an insulating sheet can be laminated on the surface of the separator to insulate the surface. However, a structure in which the separator is an insulating material and an insulating material is laminated on its surface can further improve the insulation provided by the separator.

The separator 64 is positioned in a position parallel to the end faces of the battery cells 1. In the power supply device 100 in Figure 6, the separator 64 is positioned in the middle of the insulating space 6, and insulating spaces 6 for ejected gas are provided on both sides of the separator 64. The separator 64 prevents heat (flashing heat) from the battery blocks 40A, 40B facing the separator 64 from being conducted to the battery blocks 40B, 40A located on the back side of the separator 64.
(Gas discharge direction control wall 65)

The gas discharge direction control wall 65 defines the flow path of gas when gas is discharged from the battery cell 1. By controlling the flow of gas with the gas discharge direction control wall 65, it is possible to guide the gas in any direction and safely discharge the gas from the power supply device 100 to the outside.

Figure 9 shows a perspective view of the separator 64 attached to one of the battery blocks 40A in Figure 3. As shown in this figure, the separator 64 has a gas discharge direction control wall 65 on at least one surface, which defines a gas discharge path 66 that guides the gas released when the discharge valve 2 is opened in a specified direction. With this configuration, even if the internal pressure of any of the battery cells 1 increases and gas is discharged, the gas discharge direction can be controlled by the gas discharge direction control wall 65 provided on the separator 64. As a result, the safety of the power supply device can be improved by designing it so that high-temperature and high-pressure gas is not sprayed on undesirable parts.

That is, in a power supply device 900 that connects multiple battery blocks 940A, 940B as shown in the exploded perspective view of FIG. 14, there are almost no gaps at the connection interface that connects the battery blocks 940A, 940B to each other. Therefore, in the unlikely event that gas is discharged from one of the battery cells, high-temperature and high-pressure gas will be introduced into the small gap, making it difficult to predict the route by which the gas will spread, and it is possible that the gas will leak into components that should not be exposed to high-temperature and high-pressure gas, such as protective circuits.

In particular, many battery cells have a discharge valve on the electrode surface on the positive side to discharge gas when the internal pressure rises, and in a battery block in which multiple battery cells are connected in series or parallel, it can be difficult to arrange the battery cells so that the positive electrode faces only one specific side. That is, in a power supply device 900 that connects two battery blocks 940A, 940B as shown in FIG. 14, it is sometimes impossible to arrange the battery cells so that the positive electrode faces the end side of the battery assembly 940 rather than the connection interface side between the battery blocks 940A, 940B. In such a case, if gas is discharged to the connection interface side, high temperature and high pressure gas can be introduced into the narrow gap as described above, and unintended parts can be exposed to high temperature and high pressure.

It is also possible to form an exhaust space at the connection interface between the battery blocks to introduce gas discharged from the battery cells. By injecting gas into the exhaust space, gas can be smoothly discharged from the battery cells. In particular, by making the exhaust space large-volume, the increase in internal pressure caused by the gas ejected from the exhaust port of the exhaust valve can be slowed down, making the increase in exhaust resistance gentler.

On the other hand, in a battery block using multiple battery cells, the gaps between the batteries have traditionally been filled with potting resin. By integrally adhering the potting resin to the surfaces of multiple battery cells, the thermal energy of the battery cells is conducted to the potting resin, and the potting resin provides heat capacity to protect the battery cells. In this configuration, as shown in the exploded perspective view of Figure 15, a frame 962 is formed around the exhaust space 963 to prevent the potting resin from flowing into the exhaust space 963. This also prevents the potting resin from flowing in through the exhaust port of the exhaust valve of the battery cells, impeding the exhaust of gas.

However, in this configuration, the exhaust space 963 is surrounded by the frame 962, which makes the exhaust space 963 a closed space, making it difficult for the high-temperature, high-pressure gas injected into the exhaust space 963 to escape to the outside. In addition, the high-temperature, high-pressure gas remains within the exhaust space 963, which can heat up the exhaust space 963 and expose the surrounding battery cells to high heat.

In response to this, as shown in Figures 3, 9, etc., a gas discharge direction regulating wall 65 is provided on the separator 64, so that the gas discharge direction can be regulated along the gas discharge direction regulating wall 65. As a result, the gas discharge direction regulating wall 65 can prevent high-temperature, high-pressure gas from flowing toward heat-sensitive components and guide it so that it is safely discharged outside the power supply device. As a result, even if either of the battery cells 1 contained in the opposing battery blocks 40A, 40B are positioned with their discharge valves 2 facing each other through the insulating space 6, the flow of gas during gas release can be regulated and the gas can be safely discharged outside the power supply device.

In addition, the insulating space 6 does not have a barrier such as a blocking member, such as a frame that surrounds it. Therefore, the high-temperature, high-pressure gas discharged from the battery cell 1 and introduced into the insulating space 6 is once introduced into the insulating space 6, and is then guided by the gas discharge direction control wall 65 and smoothly discharged to the outside of the insulating space 6. This makes it possible to prevent the high-temperature, high-pressure gas from being trapped between the battery blocks 40A, 40B, and to prevent the high-temperature, high-pressure gas from heating up battery cells other than the battery cell that has experienced thermal runaway.

The gas discharge direction control wall 65 is provided on the separator 64 in an area where one end face of the battery cells 1 is adjacent to each other. As a result, even if gas is discharged from one battery cell, the gas discharge direction control wall 65 interposed between the end faces prevents the gas from heating the valve that provides the exhaust valve 2 of the adjacent battery cell, thereby improving safety. In addition, by forming the gas discharge direction control wall 65 into a convex stripe, it is easy to form it integrally with the separator 64 and it also exhibits strength against gas pressure.

The gas discharge direction control wall 65 is preferably formed on both sides of the separator 64. This makes it possible to control the gas discharge direction for the battery cells arranged on both sides of the separator 64 by the gas discharge direction control wall 65 of the separator 64 interposed between the battery blocks 40A and 40B, further improving safety. However, the gas discharge direction control wall 65 may be formed only on one side of the separator 64. For example, if the battery cells can be arranged so that only the negative electrode side faces one side of the battery block, the gas discharge direction control wall may be omitted. Also, two separators each having a gas discharge direction control wall on only one side may be combined and stacked in a position where the side with the gas discharge direction control wall faces the battery block.

The gas discharge direction regulating wall 65 is preferably formed integrally with the separator 64. Alternatively, the gas discharge direction regulating wall 65 made of a separate material from the separator 64 may be bonded to the separator 64. Such a gas discharge direction regulating wall 65 may be made of glass fiber reinforced PBT. Alternatively, the separator 64 may be made of mica, glass epoxy, or aluminum, which have excellent heat resistance. The gas discharge direction regulating wall 65 may also be made of a separate material from the separator 64. In this case, the gas discharge direction regulating wall 65 may be made of the same material as the separator 64, or may be made of a heat-resistant cushioning material or rubber material.

The gas discharge direction restricting wall 65 shown in FIG. 7 and FIG. 9 is formed in a vertically extending straight line. The details of such a gas discharge direction restricting wall 65 are shown in the side views of FIG. 5 and FIG. 11. The gas discharge direction restricting wall 65 is preferably disposed between the electrodes of the battery cell 1 on the side where the exhaust valve 2 is provided. This makes it possible to prevent the gas discharged from the exhaust valve 2 from being sprayed onto the exhaust valve 2 of another adjacent battery cell, causing thermal runaway of the battery cell. As described above, the exhaust valve 2 is generally provided on the electrode on the positive electrode side, and as a result, it is preferable to provide the gas discharge direction restricting wall 65 between the positive electrodes of the battery cells 1. In the power supply device shown in FIG. 5 and the like, the gas is guided in the vertical direction in the figure by the gas discharge direction restricting wall 65. For this reason, a structure for safely discharging gas to the outside, such as an exhaust duct, is provided as necessary in the vertical direction of the power supply device.
[Embodiment 2]

However, the present invention is not limited to this configuration of the gas discharge direction control walls 65, and they can be of any shape or pattern. For example, in the power supply device according to embodiment 2, the gas discharge direction control walls 65B formed on the separator 64B are formed in straight lines parallel to each other in the horizontal direction, as shown in Fig. 12. With this configuration, the gas sprayed from the battery cells can be safely discharged from the side of the power supply device outside by passing through the insulating space with the gas discharge direction control walls 65B restricting the discharge direction to the horizontal direction in the figure.
[Embodiment 3]

In the power supply device according to the third embodiment, the gas discharge direction regulating wall 65C provided on the separator 64C can also be formed in a curved shape as shown in Fig. 13. In this way, by forming the gas discharge direction regulating wall 65C so as to surround the electrode of the battery cell provided with the exhaust valve, it is possible to regulate the gas injected from here so as not to be accidentally diffused, and to guide the gas to be discharged in the direction of the opening.
(Heat absorbing sheet 68)

Figure 10 shows a perspective view of the battery block 40A of Figure 9 with the separator 64 removed. As shown in this figure, a heat absorbing sheet 68 is arranged on the end faces of the battery blocks 40A and 40B, on the end faces of the multiple battery cells 1. The heat absorbing sheet 68 is at least partially broken by the heat and pressure of the gas released when the exhaust valve 2 is opened, allowing the gas to pass through. Meanwhile, the separator 64 is arranged at a distance from the heat absorbing sheet 68 on the end faces of the battery blocks 40A and 40B, as shown in the cross-sectional view of Figure 6. The separator 64 receives the gas that is released when the exhaust valve 2 is opened and breaks through the heat absorbing sheet 68. With this configuration, even if one battery cell 1 should accidentally release high-temperature, high-pressure gas from the exhaust valve 2, the heat absorption sheet 68 weakens the force and heat of the gas before blowing it onto the separator 64. The heat absorption sheet 68 and the weakened gas are further diffused by the separator 64, lowering the temperature and pressure and making it possible to protect the adjacent battery cell 1.

In the above configuration, an example in which two battery blocks 40A, 40B are connected to form a battery assembly has been described, but the present invention does not limit the number of battery blocks to two, and it may be three or more. In a power supply device in which three or more battery blocks are connected, the battery blocks are arranged at a distance separated by an insulating space 6. In addition, a separator 64 is arranged at each interface connecting the battery blocks, and a gas discharge direction control wall 65 is provided on the separator 64, making it possible to safely discharge gas at each connection interface.

The power supply device of the present invention can be suitably used as a power source for driving electric vehicles such as electric scooters, electric carts, and electric cars, and as a power source for home and factory power storage devices.

DESCRIPTION OF SYMBOLS 100, 900...power supply device 1...battery cell 2...vent valve 4...insulating plate 6...insulating space 8...circuit board 9...exterior case 13...end electrode; 13A...first end electrode; 13B...second end electrode 40, 940...battery assembly 40A, 40B, 940A, 940B...battery block; 40a...opposing surface 44...battery holder; 44A...insertion portion; 44B...opening 45...lead plate 64, 64B, 64C...separator 65, 65B, 65C...gas exhaust direction regulating wall 66...gas exhaust path 68...heat absorbing sheet 962...frame portion 963...exhaust space

Claims (6)

a plurality of battery cells, each of which has an exterior can extending in one direction and is formed into a cylindrical shape, and which is provided with a vent valve at one end face of the cylindrical shape for venting gas when internal pressure increases;
a plurality of battery blocks each holding the plurality of battery cells with the exterior cans in a parallel orientation and with the one end surface being flush with one of the exterior cans;
a separator disposed between the plurality of battery blocks;
A power supply device comprising:
The plurality of battery blocks are arranged to be spaced apart with insulating spaces therebetween,
at least one of the battery cells included in the battery blocks facing each other via the insulating space is arranged in a position such that the exhaust valves face each other;
the separator has a gas discharge direction control wall on at least one surface thereof, the gas discharge path defining the gas discharge passage for guiding the gas discharged in a predetermined direction when the discharge valve is opened , the gas discharge direction control wall being formed in a convex manner so as to partially provide a space in the extension direction ;
the gas discharge direction control walls are integrally formed on both sides of the separator,
A power supply device in which a heat absorbing sheet is disposed on end faces of the plurality of battery cells. 2. The power supply device according to claim 1,
The gas discharge direction control wall is provided on the separator in an area where one end faces of the battery cells are adjacent to each other. 3. The power supply device according to claim 1 ,
The gas discharge direction regulating wall is made of glass fiber reinforced PBT. The power supply device according to any one of claims 1 to 3 ,
The power supply device, wherein the separator is made of mica, glass epoxy or aluminum. The power supply device according to any one of claims 1 to 4 ,
The gas discharge direction regulating wall is formed in a curved shape. The power supply device according to any one of claims 1 to 5 , further comprising:
a power supply device comprising an exterior case that houses the plurality of battery blocks.

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