Power supply device

Abstract

This power supply device comprises: a battery pack which is obtained by disposing, in prescribed positions in a resin battery holder, a plurality of secondary battery cells having an exhaust valve that opens when internal pressure exceeds a set pressure; and an outer case inside which the battery pack is housed. The battery pack is provided with a metal horizontal structure material that passes through a center portion in the horizontal direction. A gas exhaust passage is provided which achieves communication between the inside and the outside of the battery pack via the horizontal structure material.

Description

power supply

[0001] The present disclosure relates to a power supply device that houses multiple secondary battery cells in an outer case, and in particular to a power supply device that houses secondary battery cells in an outer case that have a discharge valve that opens when the internal pressure exceeds a set pressure.

[0002] Power supply devices that house a battery pack containing multiple battery cells in an exterior case are used as power sources for energy storage systems for factories and homes, as well as for vehicles such as hybrid and electric vehicles. These power supply devices house multiple battery cells as a battery pack in an exterior case, and to ensure safety, the battery cells are equipped with a vent valve. The vent valve of the battery cell opens when the internal pressure exceeds a set pressure in an abnormal situation, preventing the battery case from bursting. Because the vent valve opens when the battery cell is being used abnormally, the gas and other ejected materials reach high temperatures and pressures, which can cause various thermal problems.

[0003] International Publication No. 2020 / 166501

[0004] In the above-described power supply device, if any battery cell experiences thermal runaway and emits high-temperature, high-pressure gas, etc., the thermal damage may spread to other battery cells, potentially resulting in the entire battery pack being ignited. As shown in FIG. 22 , if a fire spreads to a battery pack 90 consisting of multiple secondary battery cells 91, the plastic battery holder 92 may melt due to high temperatures. If the battery holder 92 melts, it may no longer be able to support the multiple secondary battery cells 91 in a predetermined orientation, resulting in the multiple secondary battery cells 91 randomly overlapping each other, as shown in FIG. 22 . When multiple secondary battery cells 91 overlap each other in this manner, an airway for venting gas emitted from the secondary battery cells 91 to the outside is not secured, resulting in the interior being filled with gas, which is undesirable. In particular, in recent years, demand for high capacity power supply devices has led to the need to house multiple secondary battery cells in a densely packed configuration. Therefore, in power supply devices equipped with such batteries, a technology for quickly venting gas generated within the battery pack to the outside is highly desirable.

[0005] A power supply device according to one aspect of the present disclosure includes a battery pack formed by arranging a plurality of secondary battery cells in fixed positions in a resin battery holder, each cell having a discharge valve that opens when the internal pressure exceeds a set pressure, and an exterior case that houses the battery pack. The battery pack includes a metal horizontal structural member that passes horizontally through the center, and a gas discharge passage that connects the inside and outside of the battery pack is provided via the horizontal structural member.

[0006] According to the power supply device of the present disclosure, a gas exhaust passage is provided that connects the inside and outside of the battery pack via a horizontal metal structural member that penetrates horizontally through the center of the battery pack. Therefore, even if a secondary battery cell experiences thermal runaway and catches fire in other secondary battery cells, causing the fire to spread to the battery pack, the gas generated inside the battery pack can be reliably exhausted to the outside of the battery pack and safely exhausted to the outside of the outer case.

[0007] FIG. 1 is a perspective view of a power supply device according to a first embodiment of the present disclosure. FIG. 2 is a vertical cross-sectional view of the power supply device shown in FIG. 1 taken along line II-II. FIG. 3 is a vertical cross-sectional view of the power supply device shown in FIG. 1 taken along line III-III. FIG. 4 is a horizontal cross-sectional view of the power supply device shown in FIG. 1 taken along line IV-IV. FIG. 5 is an exploded perspective view of the power supply device shown in FIG. 1. FIG. 6 is an exploded rear perspective view of the power supply device shown in FIG. 5, viewed from below. FIG. 7 is an exploded perspective view of the inner case of the power supply device shown in FIG. 5. FIG. 8 is an exploded rear perspective view of the inner case of the power supply device shown in FIG. 7, viewed from below. FIG. 9 is a vertical cross-sectional view of line IX-IX of the power supply device shown in FIG. 1. FIG. 10 is an enlarged cross-sectional view showing an exhaust duct of the power supply device shown in FIG. 9. FIG. 11 is an enlarged cross-sectional view of the exhaust duct of the power supply device shown in FIG. 2. FIG. 12 is an enlarged plan view of the battery pack of the power supply device shown in FIG. 4. FIG. 13 is a schematic cross-sectional view showing a state in which a fire has spread inside the power supply device according to the first embodiment of the present disclosure, causing a large number of secondary battery cells to overlap randomly. Fig. 14 is a cross-sectional perspective view showing another example of a horizontal structural member of the power supply device according to embodiment 1. Fig. 15 is a cross-sectional perspective view showing another example of a horizontal structural member. Fig. 16 is a cross-sectional perspective view showing another example of a horizontal structural member. Fig. 17 is a cross-sectional perspective view showing another example of a horizontal structural member. Fig. 18 is a cross-sectional perspective view showing another example of a horizontal structural member. Fig. 19 is a cross-sectional view showing another example of a horizontal structural member. Fig. 20 is an exploded perspective view showing an example of fixing a horizontal structural member to the outer peripheral wall of an inner case. Fig. 21 is a vertical cross-sectional view of a power supply device according to embodiment 2 of the present disclosure. Fig. 22 is a schematic cross-sectional view showing a state in which a fire has spread inside a conventional power supply device, causing a large number of secondary battery cells to overlap randomly.

[0008] A power supply device according to one embodiment of the present disclosure comprises a battery pack consisting of a plurality of secondary battery cells arranged in fixed positions in a resin battery holder, each cell having a discharge valve that opens when the internal pressure exceeds a set pressure, and an exterior case that houses the battery pack. The battery pack has a metal horizontal structural member that passes horizontally through the center, and a gas discharge passage that connects the inside and outside of the battery pack is provided via the horizontal structural member.

[0009] According to the above configuration, the assembled battery, which is made up of multiple secondary battery cells arranged in fixed positions using battery holders, is provided with a metal horizontal structural member that penetrates horizontally through the center. Therefore, even if a secondary battery cell goes into thermal runaway and emits high-temperature, high-pressure gas that causes other secondary battery cells to catch fire, leading to the fire spreading throughout the assembled battery and causing the plastic battery holder to melt and the multiple secondary battery cells to overlap in random positions, a gas exhaust passage that connects the inside and outside of the assembled battery is formed via the metal horizontal structural member, so that gas generated inside the assembled battery can be passed through the gas exhaust passage and efficiently exhausted.

[0010] In a power supply device according to another embodiment of the present disclosure, the horizontal structural members have a cross-sectional shape with a groove or a cylindrical portion and have a ventilation portion extending in the axial direction. With the above configuration, since the horizontal structural members have a cross-sectional shape with a cylindrical portion or a groove, the axially extended cylindrical portion or the groove acts as a ventilation portion through which gas can pass, allowing gas inside the battery pack to be efficiently exhausted to the outside.

[0011] In a power supply device according to another embodiment of the present disclosure, the horizontal structural members are made of structural steel. This configuration has the advantage that horizontal structural members with excellent heat resistance can be easily prepared. Furthermore, by using structural steel for the horizontal structural members, it is possible to increase rigidity while providing ventilation sections, and it is also possible to reliably ensure a gas exhaust passage even when a large external force is applied to the horizontal structural members.

[0012] In a power supply device according to another embodiment of the present disclosure, the structural steel is one of channel steel, angle steel, C-shaped steel, I-shaped steel, H-shaped steel, T-shaped steel, steel pipe, and square steel pipe. This configuration has the advantage of being able to reduce manufacturing costs by selectively using commercially available structural steel as horizontal structural members.

[0013] In a power supply device according to another embodiment of the present disclosure, the horizontal structural member has a plurality of ventilation holes formed on one of its side, vertical, or bottom surfaces. According to the above configuration, by forming a plurality of ventilation holes on one of its side, vertical, or bottom surfaces, gas generated inside the battery pack can be effectively exhausted while flowing through the ventilation holes into the ventilation section of the horizontal structural member. Furthermore, forming a plurality of ventilation holes in a metal horizontal structural member also has the advantage of being lightweight.

[0014] In another embodiment of the power supply device of the present disclosure, the battery holder has a compartment gap that extends horizontally to separate the battery pack, and horizontal structural members can be inserted into the compartment gap. With this configuration, the horizontal structural members can be inserted into the compartment gap that separates the battery pack, allowing for simple and easy insertion of the horizontal structural members that penetrate the battery pack. Furthermore, in the event of a fire spreading inside the battery pack, gases generated from the areas on both sides separated by the compartment gap can be efficiently exhausted.

[0015] In a power supply device according to another embodiment of the present disclosure, the battery holder can store multiple rechargeable battery cells arranged horizontally in a vertical orientation parallel to each other. With this configuration, even if the multiple rechargeable battery cells arranged in an upright orientation in the battery holder fall over due to the spread of fire and become randomly stacked, gas generated inside the battery pack can be efficiently discharged to the outside.

[0016] In a power supply device according to another embodiment of the present disclosure, the horizontal structural member can be fixed to the exterior case. This configuration has the advantage that by fixing the horizontal structural member to the exterior case, the exterior case can be reinforced via the horizontal structural member. Another advantage is that the horizontal structural member can be reliably positioned in a predetermined position and in the correct orientation relative to the battery block.

[0017] In another embodiment of the power supply device according to the present disclosure, the exterior case includes an inner case that houses a battery pack and an outer case that covers the inner case. The inner case is formed into a box shape by connecting a bottom plate and an upper plate with an outer peripheral wall. The bottom plate is provided with a fixing portion for fixing a horizontal structural member, and the horizontal structural member can be fixed to the fixing portion via a fixing device. According to this configuration, by fixing the horizontal structural member to the bottom plate of the inner case, the rigidity of the inner case can be increased via the horizontal structural member. Therefore, even in an abnormal situation where gas is generated inside the inner case and a large load is placed on the inner case, the reinforcement by the horizontal structural member can suppress deformation or damage of the inner case, thereby improving safety. Furthermore, since the horizontal structural member is fixed to the fixing portion provided on the bottom plate of the inner case with a fixing device, the horizontal structural member can be fixed simply and firmly.

[0018] In another embodiment of the present disclosure, the power supply device includes an outer case including an inner case that houses a battery pack and an outer case that covers the inner case. The inner case has a box shape with a bottom plate and an upper plate connected by an outer peripheral wall, and both ends of the horizontal structural members can be fixed to the outer peripheral wall via fixing members. This configuration has the advantage that the central portion of the inner case can be structurally reinforced by fixing both ends of the horizontal structural members to the outer peripheral wall of the inner case. In particular, the rigidity of the inner case can be improved by applying tension to the horizontal structural members via the fixing members fixed to the outer peripheral wall.

[0019] In another embodiment of the power supply device of the present disclosure, the outer case comprises an inner case that houses a battery pack and an outer case that covers the inner case, and the inner case has a laminated structure on a portion of its outer wall, and a laminated portion having inner and outer plates stacked on top of each other, and the laminated portion has a recess that has a predetermined depth and extends in the planar direction on the opposing surfaces of one or both of the inner and outer plates, and the recess forms a closed exhaust duct between the inner and outer plates, and the exhaust duct is connected to the inside of the inner case through an inner opening that is opened in the inner plate, and is connected to the outside of the inner case through an outer opening that is opened in the outer plate, and the inner opening and outer opening are positioned at both ends of the exhaust duct.

[0020] According to the above configuration, the gas discharged to the outside of the battery pack through the gas discharge passage is passed through an exhaust duct provided in the inner case and discharged to the outside, which has the characteristic that the gas can be safely discharged while suppressing the spread of fire inside the inner case.

[0021] In a power supply device according to another embodiment of the present disclosure, the horizontal structural member can be connected to the exhaust duct of the inner case, and the gas exhaust passage can be connected to the inside of the exhaust duct. With the above configuration, since the horizontal structural member is connected to the exhaust duct and the gas exhaust passage is connected to the inside of the exhaust duct, gas that is discharged from the inside of the battery pack through the gas exhaust passage can be efficiently flowed into the inner case and discharged to the outside of the inner case.

[0022] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to these. Furthermore, this specification in no way specifies the components set forth in the claims as components of the embodiments. The dimensions, materials, shapes, and relative positions of components described in the embodiments are not intended to limit the scope of the present invention, and are merely illustrative examples, unless otherwise specified. The size and relative positions of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present invention may be configured with the same components, so that multiple elements are served by one component, or conversely, the functions of one component may be shared by multiple components.

[0023] The power supply device of the present disclosure is suitable for use as a stationary power storage power supply for power storage systems for home, business, factory, etc., as a backup power supply for servers, or as a power supply for vehicles such as hybrid cars and electric cars, heavy machinery, etc. Below, as one embodiment of the present disclosure, a power supply device used as a power supply for a power storage system will be described.

[0024] [Embodiment 1] A power supply device according to embodiment 1 of the present disclosure is shown in Figures 1 to 11. In these figures, Figure 1 is a perspective view showing the power supply device according to embodiment 1, Figure 2 is a cross-sectional view of the power supply device of Figure 1 taken along line II-II, Figure 3 is a cross-sectional view of the power supply device of Figure 1 taken along line III-III, Figure 4 is a horizontal cross-sectional view of the power supply device of Figure 1 taken along line IV-IV, Figure 5 is an exploded perspective view of the power supply device of Figure 1, Figure 6 is an exploded rear perspective view of the power supply device of Figure 5 seen from below, Figure 7 is an exploded perspective view of the inner case, Figure 8 is an exploded rear perspective view of the inner case of Figure 7 seen from below, Figure 9 is a cross-sectional view of the power supply device of Figure 1 taken along line IX-IX, and Figures 10 and 11 are enlarged cross-sectional views showing exhaust ducts of the inner case.

[0025] The power supply device 100 shown in these figures includes a battery pack 10, which is made up of multiple secondary battery cells 1 arranged in fixed positions in battery holders 20. Each battery cell has a vent valve that opens when the internal pressure exceeds a set pressure, and an exterior case 2 that houses the battery pack 10. The battery pack 10 includes a metal horizontal structural member 7 that penetrates horizontally through the center of the battery holder 20. A gas exhaust passage 8 that connects the inside and outside of the battery pack 10 is provided through this horizontal structural member 7. The power supply device disclosed herein has a structure in which the battery pack 10, which is made up of multiple secondary battery cells 1, is housed in an exterior case 2. A particular feature of the power supply device disclosed herein is that the battery pack 10 is provided with a gas exhaust passage 8 that connects the inside and outside of the battery pack 10 through the metal horizontal structural member 7 that penetrates the center of the battery holder 20. Therefore, with regard to the structure other than the battery pack, any structure that has already been adopted in the past or that will be developed in the future can be used. The exterior case 2 for housing the battery pack 10 will be described in detail below, taking as an example an exterior case 2 including an inner case 3 and an outer case 5.

[0026] (Secondary Battery Cell 1) The power supply device 100 shown in Figures 2, 4, and 7 to 9 houses a battery pack 10, consisting of multiple secondary battery cells 1 arranged in fixed positions using battery holders 20, in an outer case 2. Each secondary battery cell 1 is a cylindrical secondary battery with a cylindrical outer can. A cylindrical secondary battery cell 1 houses an electrode assembly in a cylindrical metal outer can with a bottom, which is filled with electrolyte. The opening of the outer can is crimped and airtightly closed with a sealing body. The sealing body is airtightly fixed to the outer can via an insulating material, and this sealing body is equipped with a discharge valve that opens when the internal pressure exceeds a set pressure to discharge ejected matter such as gas. The end face of the cylindrical secondary battery cell 1 closed by the sealing body is designated as a first end face 1A, and a ring-shaped crimped ridge is formed on the outer periphery of the first end face 1A by crimping. The cylindrical secondary battery cell 1 uses the sealing body and the outer can as positive and negative electrodes.

[0027] A highly energy-efficient non-aqueous electrolyte secondary battery, such as a lithium-ion secondary battery, can be suitably used for such a secondary battery cell 1. However, the power supply device of the present disclosure does not limit the secondary battery cell to a lithium-ion secondary battery. Any rechargeable battery, such as a nickel-metal hydride battery or a nickel-cadmium battery, can also be used for the secondary battery cell.

[0028] (Battery Holder 20) Multiple rechargeable battery cells 1 are arranged in a fixed position in a predetermined orientation via the battery holder 20. The multiple rechargeable battery cells 1 are arranged horizontally in a vertical orientation, parallel to each other, with the first end faces 1A, on which the discharge valves are provided, facing upward. In this embodiment, the vertical direction is perpendicular to the horizontal. The battery holder 20 accommodates the multiple rechargeable battery cells 1 and includes multiple holding sections 21 that cover and hold the outer peripheries of the rechargeable battery cells 1. The battery holders 20 in Figures 2, 7, and 8 are divided into a first holder 20A and a second holder 20B at the midpoint of the length of the rechargeable battery cell 1, and sandwich the rechargeable battery cell 1 from both ends to hold it in a fixed position. The battery holder 20 in Figure 2 holds the multiple rechargeable battery cells 1 parallel to each other with the first end faces 1A arranged on the same plane.

[0029] The battery holder 20 shown in Figures 7 and 8 has multiple holding sections 21 that store multiple rechargeable battery cells 1 in a bale-like arrangement in a plan view. This structure, in which multiple rechargeable battery cells 1 are arranged in a bale-like arrangement, allows for space-saving storage by locating adjacent rows of rechargeable battery cells 1 in the gaps between the linearly arranged rechargeable battery cells 1. Therefore, the battery holder 20 described above can efficiently store a large number of rechargeable battery cells 1 and achieve high capacity. The battery holder 20 that stores multiple rechargeable battery cells 1 in multiple rows and columns is molded from resin in a shape in which multiple holding sections 21 are connected in multiple rows and columns. The battery holder 20 is preferably made of a material with excellent insulating and heat-resistant properties, such as a resin such as polycarbonate or ABS.

[0030] (Battery Assembly 10) Multiple secondary battery cells 1 are arranged in fixed positions using battery holders 20 to form battery blocks 11, and multiple battery blocks 11 are connected together and housed in an exterior case 2 as a battery assembly 10. The battery assembly 10 shown in FIG. 4 includes four battery blocks 11 arranged in four rows, front to back. Each battery block 11 is composed of two battery units 12 separated laterally. 35 secondary battery cells 1 are arranged in each battery unit 12, for a total of 70 secondary battery cells 1 in the battery block 11. Therefore, the battery assembly 10 has 280 secondary battery cells 1. Each battery block 11 is separated into two battery units 12 by a partition gap 24. Each battery unit 12 has 35 secondary battery cells 1 arranged in seven rows in the left-right direction and five rows in the front-to-back direction in FIG. 4. The two battery units 12 are separated into left and right sections, and each battery row has 2×7 secondary battery cells 1 arranged in the same straight line in the extension direction of the battery row, connected together by lead plates 13 .

[0031] (Lead Plates 13) As shown in FIG. 4 , the multiple secondary battery cells 1 housed in the battery holder 20 are connected to each other via lead plates 13 on the upper surface of the battery holder 20. The lead plates 13 connect the positive and negative electrodes of the secondary battery cells 1 at the first end surfaces 1A, connecting the multiple secondary battery cells 1 in parallel and in series. The secondary battery cell 1 shown in FIG. 12 has one electrode formed as a central electrode 1a located in the center of the sealing body, and the other electrode formed as a crimped ridge 1b on the outer casing. The battery block 11 shown in FIG. 4 includes multiple lead plates 13 arranged on the upper surface of the battery holder 20 along the linearly arranged battery rows between adjacent battery units 12 on the left and right. The lead plates 13 arranged between adjacent battery rows connect the secondary battery cells 1 of one linearly arranged battery row in parallel and the secondary battery cells 1 of the other linearly arranged battery row in parallel, thereby connecting the adjacent battery rows in series.

[0032] The lead plate 13 shown in Figure 12 has a main body 13A extending in the direction of the battery string. It has a first connecting tab 13a protruding from the main body 13A and connecting to the center electrode 1a of each secondary battery cell 1 in the opposing battery string, and a second connecting tab 13b protruding from the main body 13A and connecting to the crimping ridge 1b of each secondary battery cell 1 in an adjacent battery string. Insulating walls 22 are provided between the multiple lead plates 13 to insulate adjacent lead plates 13. These insulating walls 22 are positioned above the first end faces 1A of each secondary battery cell constituting the battery string and offset from the center electrode 1a to prevent short-circuiting between the series-connected secondary battery cells 1. Electrode windows 23 are opened on both sides of the insulating walls 22, exposing the center electrodes 1a and crimping ridges 1b of the secondary battery cells 1.

[0033] As described above, the lead plates 13 arranged between adjacent battery rows connect the 14 rechargeable battery cells 1 constituting the linearly arranged battery rows in parallel, and also connect adjacent battery rows in series. Thus, in the battery block 11 as a whole, 70 rechargeable battery cells 1 are connected in a 14-parallel / 5-series configuration. Furthermore, adjacent battery blocks 11 are connected in series with connecting bus bars 14, so that in the battery pack 10 as a whole, 280 rechargeable battery cells 1 are connected in a 14-parallel / 20-series configuration. The lead plates 13 and connecting bus bars 14 are made of highly conductive metal plates such as nickel or aluminum. However, the present disclosure does not limit the connection state of the multiple rechargeable battery cells to the above. The number and arrangement of the rechargeable battery cells constituting each battery block can be varied in various ways, and the arrangement of the multiple battery blocks can also be varied in various ways.

[0034] (Horizontal structural member 7, gas exhaust passage 8) Furthermore, the battery pack 10 shown in Figures 2 to 4 has a horizontal structural member 7 that penetrates four battery blocks 11 arranged in four rows, one behind the other. In the battery pack 10, the horizontal structural member 7 is arranged so that it penetrates horizontally through the center of the battery holder 20. In the battery pack 10 shown in Figure 3, a partition gap 24 is provided in the center to divide the battery block 11 into two battery units 12, one on the left and one on the right. As shown in Figure 4, the partition gaps 24 of each battery block 11 arranged in four rows, one behind the other, are arranged in a straight line, thereby dividing the entire battery pack 10 into left and right sections. The battery pack 10 is positioned in a fixed position by inserting the horizontal structural member 7 into the partition gaps 24 that connect multiple battery blocks 11. The battery pack 10 has a structure in which one battery block 11 is composed of one battery holder 20, but a partition gap 24 that penetrates the center of the battery holder 20 allows the horizontal structural member 7 to be inserted. Alternatively, the battery pack can be constructed such that one battery block is composed of two battery holders, with a partition gap formed between the two battery holders and a horizontal structural member disposed therebetween.

[0035] The horizontal structural members 7 that penetrate the battery pack 10 can have a cross-sectional shape with a groove or a cylindrical portion and a structure with a ventilation portion 70 extending in the axial direction, providing a gas exhaust passage 8 that connects the inside and outside of the battery pack 10. The horizontal structural member shown in FIG. 3 has a U-shaped groove in cross section, with the inside of this groove serving as a ventilation portion 70. A horizontal structural member 7 with this structure can efficiently exhaust gas inside the battery pack 10 to the outside using the ventilation portion 70 as a gas exhaust passage 8. As shown in FIG. 13 , even if a fire spreads inside the power supply device 100 and the battery pack 10 burns, causing the battery holders 20 to melt and resulting in a random overlap of multiple secondary battery cells 1, the horizontal structural member 7 can form gas exhaust passages 8 between the overlapping secondary battery cells 1, connecting the inside and outside of the battery pack 10, and guiding and discharging gas generated from the internal secondary battery cells 1 to the outside of the battery pack 10. Therefore, the horizontal structural members 7 are preferably shaped so that they can maintain communication between the inside and outside of the battery pack 10 and ensure an airway even when many secondary battery cells 1 are folded over and toppled over. The horizontal structural member 7 shown in Figure 3 has a U-shaped cross section, with the opening of the groove oriented sideways. This horizontal structural member 7 allows gas to flow in through the sideways opening, flow into the gas exhaust passage 8, and be exhausted to the outside.

[0036] As shown in Figure 14, horizontal structural members 7 having a U-shaped cross section can also have multiple ventilation holes 73 on the vertical surfaces 74 (side surfaces 71). A horizontal structural member 7 with this structure has the advantage that gas can flow into the interior through the ventilation holes 73 from the vertical surfaces 74, which form the bottom of the groove. Furthermore, the inclusion of ventilation holes 73 also contributes to a lightweight structure. The horizontal structural member 7A shown in Figure 14 has no ventilation holes on the upper or lower horizontal surfaces 72, but only on the vertical surfaces 74 (side surfaces 71). This structure forms ventilation holes 70 within the groove while preventing foreign objects from entering the interior by making the upper horizontal surface 72 a plate-like surface without ventilation holes. Furthermore, horizontal structural members 7 having a U-shaped cross section can also be positioned with the openings of the grooves facing downward. This structure effectively prevents foreign matter from entering the ventilation section formed by the groove, so even if the battery holder melts and multiple secondary battery cells fall over and overlap, the ventilation section can be secured to serve as a gas exhaust passage 8.

[0037] Channel steel, a type of structural steel, can be used as the horizontal structural member 7. Horizontal structural members 7 made of structural steel have the advantage of being highly rigid while providing excellent heat resistance. Furthermore, as structural steel with a cross-sectional shape having a groove or a cylindrical portion, in addition to the channel steel shown in the figure, angle steel, C-shaped steel, I-shaped steel, H-shaped steel, T-shaped steel, steel pipe, square steel pipe, etc. can also be used. Selective use of commercially available structural steel in this way reduces the cost of the horizontal structural member 7 and its manufacturing costs. However, the horizontal structural member 7 is not limited to steel; it can also be made of other metals. For example, the horizontal structural member can be manufactured from aluminum or aluminum alloys. Horizontal structural members manufactured from aluminum or aluminum alloys have the advantage of being lightweight while being able to optimize their cross-sectional shape through extrusion molding.

[0038] Another example of a horizontal structural member 7 made of structural steel is shown in Figures 15 to 18. The horizontal structural member 7B shown in Figure 15 is an angle iron. This horizontal structural member 7B can be arranged in an inverted L-shape, as shown in the figure, to form a ventilation hole 70 between the vertical surface 74 (side surface 71) and the horizontal surface 72 (top surface). This horizontal structural member 7B can also have multiple ventilation holes 73 on the vertical surface 74. Furthermore, as shown in Figure 16, the horizontal structural member 7B made of angle iron can be arranged in a mountain-shaped configuration when viewed from the front, with the two L-shaped surfaces formed as inclined surfaces 75. A horizontal structural member 7C with angle irons arranged in this way has the advantage that the ventilation holes 70 formed on the inside of the two surfaces face downward, thereby efficiently forming a gas exhaust passage 8.

[0039] The horizontal structural member 7D shown in Figure 17 is an I-beam. This horizontal structural member 7D has a ventilation section 70 formed between a vertical surface 74 located in the center and horizontal surfaces 72 connected above and below it. This horizontal structural member 7D can also have multiple ventilation holes 73 opened in the vertical surface 74.

[0040] Furthermore, the horizontal structural member 7E shown in Figure 18 is a rectangular steel pipe with a rectangular cross section. The horizontal structural member 7E with a cylindrical cross section has an internal space serving as a ventilation section 70, forming a gas exhaust passage 8. This horizontal structural member preferably has ventilation holes 73 on all surfaces except the top, such as both side surfaces 71 and the bottom surface 76, allowing gas to efficiently flow in from the outside. The horizontal structural member 7E with a cylindrical cross section thus has the advantage of stably forming a gas exhaust passage 8 inside, regardless of the installation angle, or in other words, even if the installation angle changes due to the spread of fire, thereby reliably exhausting the air inside the battery pack 10 to the outside.

[0041] As described above, by providing a horizontal structural member 7 with a cross-sectional shape including grooves or cylindrical sections, the horizontal structural member 7 can form a vent 70 within itself, effectively forming a gas discharge passage 8. However, the horizontal structural member does not necessarily have to have a cross-sectional shape including grooves or cylindrical sections. Horizontal structural members without a grooved or cylindrical cross-sectional shape can utilize their cross-sectional shape to provide an air passage below the horizontal structural member, even though they do not provide a vent. For example, the horizontal structural member 7F shown in FIG. 19 is a metal rod with a rectangular cross-sectional shape. In this case, the horizontal structural member 7F itself does not have a vent, but even when multiple rechargeable battery cells 1 are tilted so that they overlap, as shown in the figure, a space serving as an air passage 77 is provided below the horizontal structural member 7F. This is because the multiple rechargeable battery cells 1 do not tilt so that they are in close contact with the entire underside of the horizontal structural member 7F. 19 , even a horizontal structural member 7F that does not have a ventilation section has an air passage 77 below it, and this air passage 77 functions as a gas exhaust passage 8 to exhaust gas from the inside to the outside of the battery pack 10. Therefore, in this specification, the term gas exhaust passage 8 is used in a broad sense to include not only the passage formed by the ventilation section 70 of the horizontal structural member 7, but also the passage formed by the air passage 77 formed below and around the horizontal structural member 7.

[0042] The horizontal structural member 7 has a predetermined length that penetrates the battery pack 10 and is fixed to the outer case 2 via a fastener 78 to hold it in place. The fastener 78 shown in the figure is a bolt. The fastener 78, which is a bolt, is fixed in place by, for example, screwing into a fastener 79 provided on the outer case 2. The outer case 2 shown in the figure includes an inner case 3 that houses the battery pack 10, and a fastener 79 is fixed to the bottom plate 31 of the inner case 3. The fastener 79 shown in the figure is a nut member with an internal thread that can be threaded onto the fastener 78, which is a bolt. The horizontal structural member 7 is screwed to the fastener 79 via the bolt. As described above, the structure that fixes the horizontal structural member 7 to the inner case 3 has the advantage of increasing the rigidity of the inner case 3 via the horizontal structural member 7 and reinforcing it. In particular, this structure achieves the advantage of suppressing deformation or damage to the inner case 3 even in the event of an abnormality, when gas is generated inside the inner case 3 and a large load is applied to the inner case 3. Furthermore, the horizontal structural member 7 is fixed by screws to the fixing portions 79 provided on the bottom plate 31 of the inner case 3, so the horizontal structural member 7 can be easily and firmly fixed and placed in a fixed position on the battery pack 10. The horizontal structural member 7 shown in FIG. 2 is fixed to the inner case 3 via fixing portions 79 at three locations: both ends and the center. The horizontal structural member 7 shown in the figure is fixed to the inner case 3 by screwing bolts that penetrate the top and bottom surfaces of the groove-shaped member with its opening oriented horizontally into the fixing portions 79. However, the fasteners used to secure the horizontal structural member are not limited to the above structure. The horizontal structural member can be fixed in a variety of ways. Furthermore, in an outer case that does not have an inner case, fixing portions can be provided on the bottom plate of the outer case, and the horizontal structural member can be fixed in a fixed position on the outer case via these fixing portions.

[0043] Although the structure in which the lower plate 31 is fixed via the fastening portion 79 has been exemplified as the fixing structure for the horizontal structural member 7, other fixing structures can also be employed. Figure 20 shows an example of a structure for fixing the end of the horizontal structural member 7 to the outer peripheral wall 33 of the inner case 3. The illustrated fixing structure shows the horizontal structural member 7 fixed to the inner plate 35 constituting the outer peripheral wall 33 of the inner case 3 via a fixing member 46. The illustrated fixing member 46 is composed of a bracket 47 fixed to the inner plate 35 and a fastener 48 that fixes the end of the horizontal structural member 7 to the bracket 47. The illustrated bracket 47 is an L-shaped bracket including a connecting piece 47A and a fixing piece 47B. The fixing piece 47B is fixed to a predetermined position on the inner plate 35 so that the connecting piece 47A is positioned vertically along the edge of the insertion opening 44. The fixing piece 47B is fixed to the inner plate 35 by welding or screwing, for example. The connecting piece 47A has an insertion hole 47a through which the bolt 48A of the fastener 48 is inserted. The illustrated insertion hole 47a is a long hole extending horizontally, allowing the connection position with the horizontal structural member 7 to be adjusted. Furthermore, the horizontal structural member 7 has a through hole 7a penetrating the side surface 71 at a position opposite the through hole 47a in the bracket 47. A bolt 48A inserted into this through hole 7a is inserted into the through hole 47a in the bracket 47, and a nut 48B is screwed onto the tip of the bolt 48A to secure the horizontal structural member 7 to the bracket 47. The horizontal structural member 7 secured to the bracket 47 is secured in a fixed position on the outer peripheral wall 33 with the horizontal structural member 7 positioned in a predetermined orientation relative to the insertion opening 44 of the inner plate 35.

[0044] In the above-described fixing structure, the horizontal structural member 7 is fixed to the bracket 47 fixed to the inner plate 35 via fasteners 48, thereby fixing both ends of the horizontal structural member 7 to the outer peripheral wall 33 of the inner case 3. Here, the inner case 3 shown in the figure has a double-walled outer peripheral wall 33, so the structure shown is one in which the horizontal structural member 7 is fixed to the inner plate 35 of the outer peripheral wall 33. However, in an inner case having an outer peripheral wall that is not a laminated structure, both ends of the horizontal structural member can also be fixed directly to the outer peripheral wall via fasteners that penetrate the outer peripheral wall. For example, the horizontal structural member can be fixed to the outer peripheral wall by providing a bent piece on the end face of the horizontal structural member and threading a nut onto a bolt that penetrates the bent piece and the outer peripheral wall.

[0045] Alternatively, the horizontal structural member may be a round bar with threaded ends, and the fixing members may be brackets and nuts attached to both ends of the round bar. In this configuration, the bracket is attached to the outer wall of the inner case, and the round bar is fixed in place by screwing a nut onto the end of the round bar.

[0046] As described above, the structure in which both ends of the horizontal structural member 7 located in the center of the inner case 3 are fixed to the outer peripheral wall 33 of the inner case 3 enables structural reinforcement of the center of the inner case 3. In particular, this configuration has the advantage of improving the rigidity of the inner case 3 because tension is applied to the horizontal structural member 7 via fixing members 46 such as fasteners 48 and brackets 47. Furthermore, in an outer case that does not include an inner case, both ends of the horizontal structural member can be fixed to the outer peripheral wall of the outer case via fixing members to position the horizontal structural member in a fixed position. Even in this case, the structure of the center of the outer case can be reinforced by fixing both ends of the horizontal structural member located in the center of the outer case to the outer peripheral wall.

[0047] (External Case 2) The external case 2 is a metal housing having an internal storage space for storing the battery pack 10. The external case 2 preferably has a function of discharging exhaust gases emitted from the multiple secondary battery cells 1 that make up the battery pack 10 to the outside while suppressing the amount of exhaust gas emitted. Such an external case 2 may be an external case 2 made up of an inner case 3 and an outer case 5. The external case 2 shown in the figure includes the inner case 3 that stores the battery pack 10 and the outer case 5 that covers the inner case 3.

[0048] (Inner case 3) The inner case 3 shown in Figures 5 to 10 is made of metal and is formed into a box shape with a bottom plate 31 and a top plate 32 connected by an outer peripheral wall 33, and houses an assembled battery 10 inside, with multiple secondary battery cells 1 arranged in fixed positions. The inner case 3, which is made of metal plate, has a laminated structure in part of the outer peripheral wall 33. In the inner case 3 shown in the figures, opposing side walls 33X of the outer peripheral wall 33 have a laminated structure, and a laminated portion 34 is formed by an inner plate 35 and an outer plate 36 that are stacked on top of each other.

[0049] 7 and 8, the laminated portion 34 of the inner case 3 is partially provided with a recess 40 of a predetermined depth that extends in the planar direction on the outer surface of the inner plate 35, the surface that faces the outer plate 36, and partially provided with a recess 40 of a predetermined depth that extends in the planar direction on the inner surface of the outer plate 36, the surface that faces the inner plate 35. The inner plate 35 and the outer plate 36 are provided with the recesses 40 in positions that face each other, as shown in Figures 9 and 10, and the inner plate 35 and the outer plate 36 are laminated with the opposing recesses 40 facing each other, thereby forming an exhaust duct 4 with a closed structure between the inner plate 35 and the outer plate 36.

[0050] The inner plate 35 and the outer plate 36 are made of metal and have recesses 40 formed by drawing. The inner plate 35 shown in FIG. 10 has the recess 40 formed by drawing the inner plate 35 to a predetermined depth relative to the surface facing the outer plate 36. The outer plate 36 also has the recess 40 formed by drawing the outer plate 36 to a predetermined depth relative to the surface facing the inner plate 35. The depth (d) of the recess 40 can be, for example, 3 to 5 mm. Therefore, the inner width (D) of the exhaust duct 4 formed by facing the opposing recesses 40 can be 6 to 10 mm. The recesses 40 shown in FIGS. 7 and 8 are rectangular in front view and are formed to have a predetermined vertical width (L) extending in the vertical direction of the inner plate 35 and the outer plate 36, as well as a horizontal width (W) extending in the left-right direction. The vertical width (L), horizontal width (W), and depth (d) of the recesses 40 forming the exhaust duct 4 can be adjusted to adjust the volume of the exhaust duct 4.

[0051] The inner case 3 shown in Figures 5 to 10 has multiple exhaust ducts 4 on opposing side walls 33X. The multiple exhaust ducts 4 can be of the same shape and size, for example, by making the vertical width (L) and horizontal width (W) of each recess 40 equal. Furthermore, the multiple exhaust ducts 4 can be arranged at equal intervals. By arranging the multiple exhaust ducts 4 at equal intervals in this manner, the gas filling the inner case 3 can be smoothly and balancedly exhausted to the outside. The inner case 3 shown in the figures has an exhaust duct 4 with a large horizontal width (W) in the center of the side wall 33X, and three exhaust ducts 4 with smaller horizontal widths (W) than the central exhaust duct 4 are arranged at equal intervals on both sides. The size of the exhaust duct 4 is determined by the recess 40 that forms the exhaust duct 4. The vertical width (L) of the recess 40 is 50% to 80% of the height (Z) of the outer peripheral wall 33, and can be, for example, 8 to 20 cm. The width (W) of the recess 40 varies depending on the number and spacing of the exhaust ducts 4 provided in the side wall 33X, but can be, for example, 5 to 25 cm. In an inner case 3 having multiple exhaust ducts 4 provided in the side wall 33X, the total width (W) of these exhaust ducts 4 is set to, for example, 40 to 60% of the total length (X) of the side wall 33X.

[0052] However, the size, shape, and number of exhaust ducts 4 formed on the side wall 33X can be changed in various ways. For example, the multiple exhaust ducts 4 provided on the side wall 33X can be such that the exhaust duct 4 provided in the center has a wide width while the exhaust ducts 4 located on both ends have a narrow width, as shown in Figure 5, or all of the exhaust ducts 4 can have the same width. Furthermore, the arrangement and number of exhaust ducts 4 provided on the outer peripheral wall 33 of the inner case 3 can also be changed. Exhaust ducts can also be provided on the end walls of the inner case.

[0053] Furthermore, the inner plate 35 shown in FIGS. 7 to 11 has an inner opening 41 at the bottom of the recess 40. The exhaust duct 4 is connected to the interior of the inner case 3 through the inner opening 41 in the inner plate 35. The outer plate 36 shown in FIGS. 7 to 11 also has an outer opening 42 at the bottom of the recess 40. The exhaust duct 4 is connected to the outside of the inner case 3 through the outer opening 42 in the outer plate 36. The inner case 3 shown in FIGS. 9 and 10 has the inner opening 41 and the outer opening 42 located at both ends of the exhaust duct 4, thereby lengthening the exhaust path of gas passing through the exhaust duct 4. The exhaust duct 4 shown in the figures is extended in the vertical direction, with the inner opening 41 and the outer opening 42 located at both upper and lower ends. The exhaust path of this exhaust duct 4 can be lengthened by increasing the vertical width (L) of the recess 40.

[0054] 9 and 10 , the power supply device 100 has the multiple secondary battery cells 1 housed in the inner case 3 arranged so that the first end surface 1A, on which the exhaust valve is provided, faces upward, and the exhaust duct 4 formed in the stacked portion 34 of the side wall 33X is extended in the vertical direction, with the inner opening 41 opening below the exhaust duct 4 and the outer opening 42 opening above the exhaust duct 4. When the secondary battery cells 1 are arranged so that the exhaust valve faces upward in this manner, if a malfunction occurs in any of the secondary battery cells 1 and ejections such as gas are emitted, the ejection from the top side of the battery pack 10 flows toward the side wall 33X through the upper gap 15 formed between the top surface of the battery pack 10 and the top plate 32 of the inner case 3, as shown by arrow A in FIGS. At this time, if the inner opening 41 of the exhaust duct 4 provided in the side wall 33X is open to the lower side of the side wall 33X, the ejected matter such as gas flowing from the upper gap 15 toward the side wall 33X will descend along the side gap 16 formed between the side wall 33X of the inner case 3 and the battery pack 10, as shown by arrow B, and will be guided to the exhaust duct 4 from the inner opening 41 opened at the bottom of the side gap 16 and then exhausted. This lengthens the flow path of the ejected matter such as gas discharged from the secondary battery cells 1 until it is guided to the exhaust duct 4, allowing the pressure and temperature of the gas to be sufficiently reduced inside the inner case 3 before being exhausted to the outside.

[0055] Furthermore, the inner case 3 shown in Figures 5 to 10 has an inner opening 41 and an outer opening 42 that are slit-shaped and extend in the width direction. By providing openings of this shape, it is possible to effectively reduce the pressure and temperature of the gas while increasing the amount of ejected material flowing into the exhaust duct 4. The inner opening 41 and the outer opening 42 shown in Figures 7 and 8 have a slit length (s) that is 50% to 90% of the width (W) of the recess 40, and a slit width (t) that is 1 to 5 times the depth (d) of the recess 40. By adjusting the opening areas of the inner opening 41 and the outer opening 42, the inner case 3 can adjust the flow rate of ejected material such as gas flowing into the exhaust duct 4.

[0056] Furthermore, as shown in FIG. 11 , the exhaust duct 4 located in the center of the side wall 33X connects to the tip of the aforementioned horizontal structural member 7. The horizontal structural member 7 shown in the figure has an open end disposed inside the exhaust duct 4 and open to the interior of the exhaust duct 4, with the gas exhaust passage 8 communicating with the interior of the exhaust duct 4. This structure has the advantage of being able to efficiently exhaust gas generated inside the battery pack 10 to the outside of the battery pack 10 while guiding it to the exhaust duct 4 provided in the inner case 3. The inner case 3 has an insertion opening 44 formed in the inner plate 35 to connect the horizontal structural member 7 to the exhaust duct 4. The insertion opening 44 is shaped and sized to allow the horizontal structural member 7 to be inserted and to connect the gas exhaust passage 8 to the exhaust duct 4.

[0057] As described above, the inner case 3, in which the side walls 33X have a laminated structure and the exhaust duct 4 is formed in the laminated portion 34, can be composed of a lower case 30A formed by connecting inner plates 35 in a vertical position to both sides of the lower plate 31, and an upper case 30B formed by connecting outer plates 36 in a vertical position to both sides of the upper plate 32, as shown in Figures 7 and 8.

[0058] The lower case 30A has inner plates 35 connected in an upright position to both sides of a bottom plate 31 on which the battery pack 10 is placed, and fixing pieces 38 are connected to both ends of the bottom plate 31 for connecting end plates 37 of the upper case 30B and closing plates 27 that form the discharge passage 25. The tips of the fixing pieces 38 are bent inward so as to be horizontal, providing fixing portions 38A for fixing the battery holders 20 of the battery pack 10. The battery pack 10 is fixed to the fixing portions 38A of the fixing pieces 38 via set screws 19 that pass through bosses 20a on the battery holders 20. An insulating sheet 18 is laid on the underside of the battery pack 10 fixed to the lower case 30A to insulate the multiple rechargeable battery cells 1 from the bottom plate 31. The above-mentioned lower case 30A is formed by cutting a metal plate into a predetermined shape, forming a recess 40 in the inner plate 35 by drawing, opening an inner opening 41 by punching, and bending the inner plate 35 and the fixing piece 38 so that they assume a predetermined posture relative to the lower plate 31.

[0059] The upper case 30B has outer plates 36 connected to both sides of the top plate 32 in a vertical position, and an end plate 37 connected to one end of the top plate 32 in a vertical position. The upper case 30B shown in the figures is reinforced by providing multiple stepped uneven portions 39 on the top plate 32. The stepped uneven portions 39 are convex portions that protrude upward from the main body of the planar top plate 32 and extend in a width direction that intersects with the extension direction of the side walls 33X in a plan view. The multiple stepped uneven portions 39 are provided at equal intervals and parallel to each other. The upper case 30B is formed by cutting a metal plate into a predetermined shape, forming recesses 40 in the outer plate 36 and stepped uneven portions 39 in the top plate 32 by drawing, opening outer openings 42 by punching, and bending the outer plate 36 and end plate 37 so that they are in a predetermined position relative to the top plate 32.

[0060] As shown in Figures 9 and 10, the inner case 3 is formed by stacking an outer plate 36 of an upper case 30B on the outside of an inner plate 35 provided on a lower case 30A and connecting the lower case 30A and the upper case 30B together. This structure simply and easily forms a stacked structure for the side wall 33X by connecting the lower case 30A, which has inner plates 35 on both sides, and the upper case 30B, which has outer plates 36 on both sides. The stacked inner plate 35 and outer plate 36 are firmly fixed in close contact with each other, for example, by screws. Furthermore, the upper case 30B shown in the figures includes an end plate 37 connected in a vertical position to one end of the top plate 32. This end plate 37 is fixed by screws to a fixing piece 38 connected to one end of the bottom plate 31.

[0061] The inner case can also be configured with a lower case having outer plates connected vertically to both sides of a lower plate, and an upper case having upper plates connected vertically to both sides of a top plate. This inner case is connected to the upper case by stacking the outer plate and the inner plate with the inner plate provided on the upper case inserted inside the outer plate provided on the lower case to form a stacked portion.

[0062] Furthermore, the inner case 3 has one of the opposing end walls 33Y of the outer peripheral wall 33 closed by an end plate 37, and the other has a discharge path 25 of the collision structure that communicates with the interior of the inner case 3. The discharge path 25 of the collision structure shown in Figure 4 includes a pair of collision plates 26 provided on both sides of the end face of the inner case 3, and a closing plate 27 that is positioned closer to the battery pack 10 than the collision plates 26 and is fixed to a fixing piece 38, with a gap 28 formed between it and both side walls 33X. The pair of collision plates 26 have central tip portions bent inward to form bent portions 26A, and both ends of the closing plate 27 are bent toward the collision plate 26 to form bent pieces 27A. 4 , the exhaust path 25 of this structure causes gas passing through the gap 28 between the bent piece 27A of the closing plate 27 and the side wall 33X to collide with the collision plate 26, and also causes the gas, whose flow direction has been changed by the collision plate 26, to change direction toward the closing plate 27 at the bent portion 26A of the collision plate 26 and collide with the closing plate 27, and then is exhausted to the outside through a wiring opening 29 opened in the end face. This exhaust path 25 snakes the lead wires and output lines drawn from the battery pack 10 in a non-linear manner to lead them out of the inner case 3, preventing ejected material such as gas emitted from the secondary battery cells 1 from turning into a straight-traveling flame and being sprayed out of the inner case 3.

[0063] (Outer Case 5) As shown in Figures 1 to 6, the outer case 5 has a box-like exterior and is hollow, housing the inner case 3 that houses the battery pack 10. The outer case 5 shown in the figures has a structure made up of a combination of multiple metal plates. In the example shown in the exploded perspective views of Figures 5 and 6, the outer case 5 has a box-like overall exterior shape, with a bottom plate 51 and a top plate 52 that are arranged opposite each other and connected by side plates 53 on both sides and end plates 54 on both ends.

[0064] 5 and 6 is composed of a first case 50A formed by connecting side plates 53 to both sides of a top plate 52 and connecting an end plate 54 to one end of the top plate 52, a second case 50B formed by providing fixing pieces 55 on both sides and one end of a bottom plate 51 for fixing the side plates 53 and end plates 54 of the first case 50A, and a third case 50C equipped with a closing plate 56 disposed on the end face opposite the end plate 54 provided on the first case 50A. The outer case 5 is formed by connecting these cases together to form an overall box-like outer shape.

[0065] 5 and 6 has a plurality of stepped uneven portions 58 on the bottom plate 51. The stepped uneven portions 58 are convex portions that protrude upward from the main body of the flat bottom plate 51 and extend in the short direction of the outer case 5. The stepped uneven portions 58 are arranged parallel to one another and reinforce the bottom plate 51 to which the inner case 3 is fixed.

[0066] 5 and 6 also has a plurality of stepped uneven portions 59 on the top plate 52. The stepped uneven portions 59 on the top plate 52 are convex portions that protrude downward relative to the flat main body of the top plate 52 and extend in the short direction of the outer case 5. The stepped uneven portions 59 are parallel to one another, and in particular, the stepped uneven portions 59 protruding downward from the top plate 52 are arranged alternately opposite the stepped uneven portions 39 protruding upward on the top plate 32 of the inner case 3. With this structure, the stepped uneven portions 59 protruding downward from the top plate 52 of the outer case 5 are positioned in recesses formed by the stepped uneven portions 39 protruding upward from the top plate 32 of the inner case 3, thereby reinforcing the outer case 5 and preventing the outer shape of the outer case 5 from becoming larger.

[0067] (Hole 57) Furthermore, the outer case 5 has multiple hole 57 on its outer surface to allow gas to pass through so that jets of gas and other materials emitted from the rechargeable battery cells 1 housed in the inner case 3 and discharged outside the inner case 3 can be discharged outside the outer case 5 without burning. The outer case 5 shown in the figure has multiple hole 57 formed by arranging a metal mesh 57A on the end plate 54 on the end surface. However, the outer case can also have punched metal disposed as multiple holes. By discharging high-temperature, high-pressure gas from the inner case to the outside of the outer case 5 through the multiple hole 57, the outer case described above can effectively prevent external flames caused by jets of gas and other materials from the rechargeable battery cells 1 burning and being sprayed outside the outer case 5.

[0068] (Circuit Board 61) Furthermore, the power supply device 100 shown in Figures 3 to 6 has a circuit board 61 located in a board chamber 60 provided in the third case 50C on the other end surface side of the outer case 5. The third case 50C shown in Figures 3 and 4 forms a board chamber 60 separated from the internal space of the outer case 5 by a shielding plate 62 arranged inside the closing plate 56, protecting the circuit board 61 from jets of high-temperature, high-pressure gas and other objects emitted from the inner case 3. The circuit board 61 is equipped with a charge / discharge circuit that charges and discharges the rechargeable battery cells 1, a protection circuit that monitors the voltage and temperature of the rechargeable battery cells 1 and cuts off the current in the event of an abnormality, and other such circuits. Furthermore, the outer case 5 shown in the figures has positive and negative output terminals 63 and signal terminals 64 connected to the circuit board 61 exposed from the closing plate 56 of the third case 50C.

[0069] In the outer case 5 described above, the inner case 3 is fixed to the bottom plate 51 of the second case 50B, and the lead wires and output lines drawn from the inner case 3 are connected to the circuit board 61 of the third case 50C fixed to the second case 50B, after which the first case 50A is joined to the second case 50B and the third case 50C. The side plates 53 and end plates 54 of the first case 50A are fixed to the fixing pieces 55 of the second case 50B with fixing screws 69, and the third case 50C is fixed to the other end of the first case 50A with fixing screws 69, forming the outer case 5 into a box shape.

[0070] [Embodiment 2] The power supply device 100 described above has one horizontal structural member 7 that penetrates the center of the battery pack 10, but multiple horizontal structural members 7 may also be disposed to penetrate the battery pack 10. The power supply device 200 shown in FIG. 21 has two horizontal structural members 7 disposed in the battery pack 10. The number and arrangement of the rechargeable battery cells 1 housed in the battery pack 10 are individually designed depending on the intended use and purpose. Therefore, the power supply device can change the number of horizontal structural members disposed in the battery pack depending on the number and arrangement of the rechargeable battery cells housed in the battery pack. By providing two horizontal structural members 7, the power supply device 200 shown in the figure can efficiently exhaust gas generated inside the battery pack 10 to the outside.

[0071] The power supply device according to the present disclosure can be suitably used for stationary power storage applications, such as as a power source for power storage systems for home, business, or factory use, as a backup power source for servers, or as a power source for vehicles such as hybrid cars and electric cars.

[0072] 100, 200 Power supply device 1 Secondary battery cell 1A First end face 1a Central electrode 1b Crimping ridge 2 Outer case 3 Inner case 4 Exhaust duct 5 Outer case 7 Horizontal structural member 7a Through hole 8 Gas exhaust passage 10 Assembled battery 11 Battery block 12 Battery unit 13 Lead plate 13A Main body 13a First connecting tab 13b Second connecting tab 14 Connecting bus bar 15 Upper gap 16 Side gap 18 Insulating sheet 19 Set screw 20 Battery holder 20A First holder 20B Second holder 20a Boss portion 21 Holding portion 22 Insulating wall 23 Electrode window 24 Partition gap 25 Discharge path 26 Collision plate 26A Bent portion 27 Closure plate 27A Bent piece 28 Gap 29 Wiring opening 30A Lower case 30B Upper case 31 Lower plate 32 Upper plate 33 Outer peripheral wall 33X Side wall 33Y End wall 34 Laminated portion 35 Inner plate 36 Outer plate 37 End plate 38 Fixing piece 38A Fixing portion 39 Stepped uneven portion 40 Recess 41 Inner opening 42 Outer opening 44 Insertion opening 46 Fixing member 47 Bracket 47A Connecting piece 47a Insertion hole 47B Fixing piece 48 Fixing tool 48A Bolt 48B Nut 50A First case 50B Second case 50C Third case 51 Bottom plate 52 Top plate 53 Side plate 54 End plate 55 Fixing piece 56 Closure plate 57 Hole 57A Metal mesh 58 Step uneven portion 59 Step uneven portion 60 Board chamber 61 Circuit board 62 Shielding plate 63 Output terminal 64 Signal terminal 69 Fixing screw 70 Ventilation portion 71 Side surface 72 Horizontal surface 73 Ventilation hole 74 Vertical surface 75 Inclined surface 76 Bottom surface 77 Airway 78 Fixing device 79 Fixing portion 90 Battery pack 91 Secondary battery cell 92 Battery holder

Claims

1. A power supply device comprising: a battery pack consisting of a plurality of secondary battery cells arranged in fixed positions in a resin battery holder, each of which has a discharge valve that opens when the internal pressure exceeds a set pressure; and an exterior case which houses the battery pack, wherein the battery pack has a metallic horizontal structural member which penetrates horizontally through the center, and a gas discharge passageway which connects the inside and outside of the battery pack via the horizontal structural member.

2. A power supply device as claimed in claim 1, wherein the horizontal structural member has a cross-sectional shape with a groove or a tube portion and has a ventilation portion extending in the axial direction.

3. The power supply device according to claim 2, wherein the horizontal structural member is a steel beam.

4. A power supply device according to claim 3, wherein the structural steel is any one of a channel steel, an angle steel, a C-shaped steel, an I-shaped steel, an H-shaped steel, a T-shaped steel, a steel pipe, and a square steel pipe.

5. A power supply device as claimed in claim 2, wherein the horizontal structural member has a plurality of ventilation holes formed on any one of the side, vertical or bottom surfaces.

6. A power supply device as claimed in any one of claims 1 to 5, wherein the battery holder has a partition gap which partitions the battery pack and extends in the horizontal direction, and the horizontal structural member is inserted into the partition gap.

7. A power supply device according to any one of claims 1 to 5, wherein the battery holder is a battery pack in which the plurality of secondary battery cells are stored in an up-down orientation, aligned horizontally and parallel to each other.

8. A power supply device according to any one of claims 1 to 5, wherein the horizontal structural member is fixed to the exterior case.

9. A power supply device as described in claim 8, wherein the exterior case comprises an inner case for housing the battery pack, and an outer case for covering the inner case, the inner case is formed into a box shape with a lower plate and an upper plate connected by an outer peripheral wall, and a fixing portion for fixing the horizontal structural member is provided on the lower plate, and the horizontal structural member is fixed to the fixing portion via a fixing device.

10. A power supply device as described in claim 8, wherein the exterior case comprises an inner case for housing the battery pack, and an outer case for covering the inner case, the inner case being formed into a box shape with a lower plate and an upper plate connected by an outer peripheral wall, and both ends of the horizontal structural member being fixed to the outer peripheral wall via fixing members.

11. A power supply device according to any one of claims 1 to 5, wherein the outer case comprises an inner case for housing the battery pack, and an outer case covering the inner case, the inner case comprises a laminated portion having an inner plate and an outer plate laminated on each other with a portion of the outer peripheral wall being a laminated structure, the laminated portion has a recess having a predetermined depth and extending in the planar direction partially provided on the opposing surfaces of either or both of the inner plate and the outer plate, and the recess forms a closed exhaust duct between the inner plate and the outer plate, the exhaust duct communicates with the inside of the inner case via an inner opening opened in the inner plate, and communicates with the outside of the inner case via an outer opening opened in the outer plate, the inner opening and the outer opening being positioned at both ends of the exhaust duct.

12. A power supply device according to claim 11, wherein said horizontal structural member is connected to said exhaust duct of said inner case, and said gas exhaust passage communicates with the inside of said exhaust duct.

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