JP7516809B2 - Power storage device - Google Patents

Description

The present invention relates to an energy storage device that includes an energy storage element and an exterior body that houses the energy storage element.

Patent Document 1 discloses a battery module that includes a stack of multiple rectangular battery cells and a pair of end plates arranged on both sides of the stack in the stacking direction. In this battery module, a protrusion is arranged between the endmost rectangular battery cell and the end plate, protruding from one of the rectangular battery cell and the end plate toward the other.

JP 2019-160693 A

In the above-mentioned conventional battery module (energy storage device), a protrusion between the end plate and the rectangular battery cell (energy storage element) at the very end of the stack (energy storage element row) ensures a gap between the energy storage element and the end plate for the energy storage element to displace. This aims to suppress deformation of the energy storage elements at the ends of the energy storage element row. However, such a configuration that allows the energy storage elements to displace can, for example, cause the energy storage elements to displace and press against the exterior body that houses the energy storage element row from the inside, which can cause a safety issue such as deformation or damage to the exterior body.

The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and aims to provide a storage device with improved safety and a simple configuration.

The energy storage device according to one aspect of the present invention comprises an energy storage element array consisting of a plurality of energy storage elements arranged in a first direction, a pair of end plates sandwiching the energy storage element array in the first direction, and an exterior body having a main body portion that houses the energy storage element array and the pair of end plates, the main body portion being formed in a box shape having an opening on a side in a second direction intersecting with the first direction, and the pair of end plates being connected by a connecting member arranged on the second direction side of the energy storage element array, and not connected on the other direction side.

According to this configuration, since the connecting member connecting the pair of end plates is disposed on the side of the opening of the exterior body, the possibility of the opening side of the box-shaped main body being deformed to widen when one or more energy storage elements swells is reduced. In other words, the connecting member connecting the pair of end plates is located in the part of the main body that is easily deformed, and the box-shaped main body is located on the side of the energy storage element array where there is no connecting member. This allows the pair of end plates and the main body to efficiently suppress bulging of the energy storage element array. In addition, since only one connecting member is required inside the exterior body, the configuration for restraining the energy storage element array can be simplified and the energy storage device can be made smaller. In this way, the energy storage device according to this embodiment is an energy storage device with improved safety and a simple configuration.

Each of the plurality of storage elements may have a gas exhaust valve and be arranged with the gas exhaust valve facing the second direction, and the connecting member may be arranged in a position facing the gas exhaust valves of the plurality of storage elements and have a through hole that penetrates in the second direction.

According to this configuration, the connecting member applies a restraining force in a first direction to the pair of end plates, and when any of the storage elements is opened, the gas discharged from the gas discharge valve can be sent in a second direction. This makes it possible to efficiently discharge the gas to the outside. This, for example, suppresses an increase in the internal pressure of the exterior body, and as a result, reduces the possibility of deformation or damage to the exterior body due to an increase in internal pressure.

Each of the plurality of storage elements may have a gas exhaust valve and be arranged with the gas exhaust valve facing the second direction, and the connecting member may be arranged in a position facing the gas exhaust valves of the plurality of storage elements and may have a flow path forming portion that forms a gas flow path extending in the first direction.

According to this configuration, the connecting member applies a restraining force in a first direction to the pair of end plates, and when any of the storage elements is opened, the gas discharged from the gas discharge valve can be sent in the arrangement direction of the storage elements. This makes it possible to efficiently discharge the gas to the outside. This, for example, suppresses an increase in the internal pressure of the exterior body, and as a result, reduces the possibility of deformation or damage to the exterior body due to an increase in internal pressure. In addition, since there is no need to use a separate member that forms a gas flow path, this contributes to simplifying or miniaturizing the configuration of the storage device.

The present invention provides a simple configuration of an energy storage device with improved safety.

1 is a perspective view showing an external appearance of a power storage device according to an embodiment; FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. 1 is a first perspective view showing the appearance of a restraint member and an energy storage element array according to an embodiment; 11 is a second perspective view showing the appearance of the restraint member and the energy storage element array according to the embodiment; FIG. 4 is a cross-sectional view showing the structural relationship between an energy storage element array, a restraining member, and a main body portion according to the embodiment. FIG. FIG. 11 is a perspective view showing the appearance of a restraining member and an energy storage element array according to a modified example of the embodiment. FIG. 4 is a cross-sectional view of a connecting member according to an embodiment.

The following describes an energy storage device according to an embodiment of the present invention (including its modified examples) with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement positions, and connection forms shown in the following embodiments are merely examples and are not intended to limit the present invention. Also, the dimensions in each figure are not strictly shown.

In the following description and drawings, the X-axis direction is defined as the arrangement direction of multiple energy storage elements, the direction in which the long sides of the energy storage element container face each other, or the thickness direction of the container. The Y-axis direction is defined as the arrangement direction of the electrode terminals of one energy storage element, or the direction in which the short sides of the energy storage element container face each other. The Z-axis direction is defined as the arrangement direction of the main body and the lid in the exterior body of the energy storage device, the arrangement direction of the energy storage element and the bus bar, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect with each other (orthogonal in the following embodiments and their modifications). Depending on the mode of use, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the Z-axis direction will be described as the up-down direction below.

In the following embodiments, expressions such as parallel and perpendicular that indicate relative directions or attitudes may be used, but these expressions may not strictly refer to those directions or attitudes. For example, two directions being parallel does not only mean that the two directions are completely parallel, but also means that the two directions are substantially parallel, that is, that there is a difference of, for example, about a few percent. In the following description, for example, the positive direction of the X-axis indicates the direction of the arrow on the X-axis, and the negative direction of the X-axis indicates the direction opposite to the positive direction of the X-axis. Furthermore, when the term X-axis direction is simply mentioned, it means either one of two directions parallel to the X-axis. The same applies to terms related to the Y-axis and Z-axis.

(Embodiment)
[1. General Description of the Power Storage Device]
First, an overall description of a power storage device 1 according to an embodiment will be given with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the external appearance of the power storage device 1 according to an embodiment. Fig. 2 is an exploded perspective view of the power storage device 1 according to an embodiment.

The storage device 1 is a device that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. For example, the storage device 1 is a battery module (battery pack) used for power storage or power source applications. Specifically, the storage device 1 is used as a battery for driving or starting the engine of a moving object such as an automobile, motorcycle, watercraft, ship, snowmobile, agricultural machinery, construction machinery, or railroad vehicle for electric railway. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and gasoline-powered automobiles. Examples of the above-mentioned railroad vehicles for electric railways include trains, monorails, and linear motor cars. The storage device 1 can also be used as a stationary battery for home use or for power generation.

1 and 2, the energy storage device 1 includes a plurality of energy storage elements 20, an exterior body 10 that houses the plurality of energy storage elements 20, and a restraining member 50. In this embodiment, the exterior body 10 houses eight energy storage elements 20. The number of energy storage elements 20 included in the energy storage device 1 is not limited to eight. The energy storage device 1 may include one or more energy storage elements 20. In this embodiment, one energy storage element row 24 is formed by a plurality of energy storage elements 20 arranged in the X-axis direction, and the energy storage element row 24 is subjected to a restraining force in the X-axis direction by the restraining member 50. The X-axis direction is an example of a first direction. The energy storage element row 24 may include spacers and insulating films, not shown.

The exterior body 10 has a main body 12 that houses the storage element array 24, and a lid 11. A bus bar plate 17 is disposed between the storage element array 24 housed in the main body 12 and the lid 11. A plurality of bus bars 33 are held on the bus bar plate 17. For example, conductive members such as electric wires and electrical equipment such as a control circuit are disposed between the bus bar plate 17 and the lid 11, but illustration and description of these are omitted.

The exterior body 10 is a rectangular (box-shaped) container (module case) that constitutes the outer shell of the energy storage device 1. In other words, the exterior body 10 is a member that fixes the energy storage element array 24 and the bus bar plate 17, etc., in predetermined positions and protects them from impacts and the like. The exterior body 10 is formed of an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyether sulfone (PES), ABS resin, or a composite material thereof, or a metal with an insulating coating, etc.

The lid 11 of the exterior body 10 is a rectangular member that closes the opening 15 of the main body 12, and has a positive electrode side external terminal 91 and a negative electrode side external terminal 92. The external terminals 91 and 92 are electrically connected to the multiple storage elements 20, and the storage device 1 charges with electricity from the outside and discharges electricity to the outside via the external terminals 91 and 92. The external terminals 91 and 92 are formed of a conductive material made of metal, such as aluminum or an aluminum alloy.

The cover 11 is provided with a ventilation chamber (not shown) through which gas moving from the inside or outside of the exterior body 10 passes, and an exhaust pipe 90 that connects the inside of the ventilation chamber to the outside of the exterior body 10. For example, gas inside the exterior body 10 is discharged to the outside of the exterior body 10 through the ventilation chamber and the exhaust pipe 90. More specifically, a valve member that opens when the pressure inside the exterior body 10 (internal pressure) rises to a predetermined value is disposed in the ventilation chamber. Therefore, even if foreign matter such as water or dust flows into the ventilation chamber through the exhaust pipe 90 under normal circumstances, the valve member substantially prevents the foreign matter from flowing into the interior of the exterior body 10. In addition, for example, when the internal pressure of the exterior body 10 becomes equal to or greater than a predetermined value due to the discharge of gas from the energy storage element 20, the valve member opens, and the gas inside the exterior body 10 is discharged from the exhaust pipe 90 to the outside of the exterior body 10 through the ventilation chamber.

The main body 12 of the exterior body 10 is a bottomed rectangular cylindrical housing (enclosure) with an opening 15 formed on the side in the positive direction of the Z axis for accommodating the energy storage element array 24. With the opening 15 covered by the lid 11, the periphery of the opening 15 and the lid 11 are joined by, for example, thermal welding. This ensures airtightness at the opening 15. The positive direction of the Z axis is an example of the second direction.

The energy storage element 20 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The energy storage element 20 has a flattened rectangular parallelepiped shape (square shape), and in this embodiment, as described above, eight energy storage elements 20 are arranged in the X-axis direction.

In this embodiment, the energy storage element 20 includes a metal container 21. The container 21 is a rectangular case having a pair of opposing long sides 21a and a pair of opposing short sides 21b. The container 21 contains an electrode body, a current collector, an electrolyte, and the like. In this embodiment, each of the multiple energy storage elements 20 is arranged in a row in the X-axis direction with the long sides 21a facing the X-axis direction (the short sides 21b parallel to the X-axis direction).

The cover plate 21c of the container 21 is provided with metal electrode terminals 22 (positive and negative terminals) electrically connected to the electrode body inside the container 21. The cover plate 21c of the container 21 is further provided with a gas exhaust valve 23 for exhausting gas inside the container 21 to the outside. The gas exhaust valve 23 has a function of exhausting gas inside the container 21 to the outside of the container 21 by opening (opening the valve) when the internal pressure of the container 21 increases due to evaporation of the electrolyte inside the container 21, for example. The gas exhaust valve 23 having such a function is provided in each of the multiple storage elements 20. In this embodiment, as shown in FIG. 2, each of the multiple storage elements 20 is arranged in a position in which the gas exhaust valve 23 faces the positive direction of the Z axis.

The energy storage element 20 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 20 may also be a primary battery that allows the user to use stored electricity without charging it. In the present embodiment, the energy storage element 20 is illustrated as having a rectangular parallelepiped (corner) shape, but the shape of the energy storage element 20 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape, a cylindrical shape, an oval cylindrical shape, or the like other than a rectangular parallelepiped shape. Furthermore, a laminate type energy storage element may be provided in the energy storage device 1 as the energy storage element 20.

The bus bar 33 is a rectangular plate-like member that is arranged on at least two storage elements 20 while being held by the bus bar plate 17, and electrically connects the electrode terminals 22 of the at least two storage elements 20. The material of the bus bar 33 is not particularly limited, and may be formed of, for example, metals such as aluminum, aluminum alloy, copper, copper alloy, stainless steel, or a combination thereof, or a conductive material other than metal. In this embodiment, five bus bars 33 are used to connect two storage elements 20 in parallel to form four sets of storage element groups, and the four sets of storage element groups are connected in series. In addition, there is no particular limit to the manner of electrical connection of the eight storage elements 20, and for example, all of the eight storage elements 20 may be connected in series by seven bus bars.

The busbar plate 17 is a resin member that holds the busbars 33. The busbar plate 17 holds the multiple busbars 33 as well as a control circuit and electric wires (not shown) and regulates the positions of these components. The busbar plate 17 has multiple busbar openings 17a that hold each of the multiple busbars 33 and expose a portion of each of the multiple busbars 33 to the side of the multiple energy storage elements 20.

At the center of the bus bar plate 17 in the Y-axis direction, a flow path forming portion 19 is provided that extends in the X-axis direction and protrudes in the Z-axis positive direction along the arrangement of the gas exhaust valves 23 of the multiple storage elements 20. The flow path forming portion 19 covers all the gas exhaust valves 23 from the Z-axis positive direction. At the longitudinal ends of the flow path forming portion 19, flow path outlets 18 are provided on both the X-axis positive side and the X-axis negative side, as shown in FIG. 2. Therefore, the gas exhausted from the storage elements 20 mainly passes through the flow path outlets 18 and is released to the outside of the exterior body 10 via the above-mentioned ventilation chamber and exhaust pipe 90. The bus bar plate 17 configured in this manner is fixed to the main body portion 12 of the exterior body 10 by a predetermined method, such as adhesive or heat welding.

The restraining member 50 is a member that applies a restraining force to the storage element array 24 in the arrangement direction (arrangement direction) of the storage elements 20. The restraining member 50 has a pair of end plates 51 and a connecting member 52. In this embodiment, each of the pair of end plates 51 is disposed between the storage element array 24 and the wall portion 13a (see FIG. 2) that faces the main body portion 12 in the X-axis direction. The restraining member 50 and its surrounding configuration will be described below with reference to FIGS. 3 to 5.

[2. Configuration of Restraint Member and Its Surrounding Area]
Fig. 3 is a first perspective view showing the appearance of the restraining member 50 and the energy storage element array 24 according to the embodiment. Fig. 4 is a second perspective view showing the appearance of the restraining member 50 and the energy storage element array 24 according to the embodiment. Fig. 3 illustrates a state in which the restraining member 50 is attached to the energy storage element array 24, and Fig. 4 illustrates a state in which the restraining member 50 is removed from the energy storage element array 24. Fig. 5 is a cross-sectional view showing the structural relationship between the energy storage element array 24, the restraining member 50, and the main body portion 12 according to the embodiment. Fig. 5 illustrates a schematic cross-section of the main body portion 12 and the restraining member 50 in an XZ plane passing through the center of the main body portion 12 in the Y-axis direction, and each energy storage element 20 is illustrated not in cross-section but in side view.

As shown in Figs. 3 to 5, the restraining member 50 according to this embodiment has a pair of end plates 51 that sandwich the energy storage element array 24 in the X-axis direction, and a connecting member 52 that connects the pair of end plates 51. In this embodiment, the restraining member 50 is a member formed of a metal such as iron or an aluminum alloy. For example, each of the pair of end plates 51 and the connecting member 52 are fabricated as separate parts, and then joined by a method such as welding, fastening, or crimping. Note that the restraining member 50 that integrally includes the pair of end plates 51 and the connecting member 52 may be fabricated, for example, by integral molding using additive manufacturing or casting, or by bending a single metal plate.

Each of the pair of end plates 51 is arranged facing the long side surface 21a of the storage element 20 at the end of the storage element row 24. Specifically, the end plate 51 is arranged with, for example, a resin end spacer (not shown) sandwiched between the end plate 51 and the storage element 20. This ensures electrical insulation between the end plate 51 and the storage element 20. In addition, the container 21 of the storage element 20 is protected by the end spacer, so that damage to the container 21 due to interference between the relatively rigid end plate 51 and the container 21 of the storage element 20 is suppressed. Note that the restraining member 50 may have electrical insulation between the storage element 20 and the like, for example, by coating the surface with a resin material. In addition, an insulating member such as a resin film may be arranged in a range close to the end plate 51 or the connecting member 52 of each of the multiple storage elements 20 or the entire storage element row 24.

In addition, in this embodiment, as shown in Figures 2 to 4, the pair of end plates 51 are connected only by a connecting member 52 arranged on the side of the energy storage element array 24 in the positive direction of the Z axis, and are not connected on the other sides. In other words, when viewed from the X axis direction, only one of the four sides of the rectangular end plate 51 is connected to the other end plate 51. As a result, for example, no space is required to place the connecting member 52 on the side (the side in the positive direction of the Y axis and the side in the negative direction of the Y axis) or the bottom side (the side in the negative direction of the Z axis) of the energy storage element array 24. Therefore, the structure consisting of the energy storage element array 24 and the restraining member 50 can be made compact as a whole.

When at least one energy storage element 20 in the energy storage element array 24 attempts to expand, the pair of end plates 51 are connected only by the connecting member 52 on the side in the positive direction of the Z axis, and therefore can be said to be prone to deformation so as to open on the other side. However, in this embodiment, as shown in FIG. 5, the connecting member 52 is disposed on the side of the opening 15 of the main body 12 of the exterior body 10, and displacement of the pair of end plates 51 in the part of the main body 12 that is not connected by the connecting member 52 can be suppressed.

Thus, the energy storage device 1 according to this embodiment includes an energy storage element array 24 consisting of a plurality of energy storage elements 20 arranged in a first direction (X-axis direction), a pair of end plates 51 sandwiching the energy storage element array 24 in the X-axis direction, and an exterior body 10. The exterior body 10 has a main body 12 that houses the energy storage element array 24 and the pair of end plates 51. The main body 12 is formed in a box shape having an opening 15 on the side in the second direction (Z-axis positive direction) that intersects with the X-axis direction. The pair of end plates 51 are connected by a connecting member 52 arranged on the Z-axis positive side of the energy storage element array 24, and are not connected on the other side.

With this configuration, the connecting member 52 connecting the pair of end plates 51 is disposed on the side of the opening 15 of the exterior body 10, so that when one or more energy storage elements 20 swell, the possibility of the opening 15 side of the box-shaped main body 12 deforming in such a way that it widens is reduced. In other words, the connecting member 52 connecting the pair of end plates 51 is located in the part of the main body 12 that is easily deformed, and the box-shaped main body 12 is present on the side of the energy storage element array 24 where the connecting member 52 is not located. As a result, the pair of end plates 51 and the main body 12 efficiently suppress the bulging of the energy storage element array 24.

More specifically, for example, a case is assumed in which the electrolyte rapidly vaporizes inside the container 21 of the energy storage element 20, causing the long side surface 21a of the energy storage element 20 to expand. In this case, if there is no restraining member 50, the energy storage element row 24 expands in the X-axis direction, and as a result, a pressing force is applied from the energy storage element row 24 to the wall portion 13a of the main body portion 12. This causes the opening 15 to open (the wall portion 13a to collapse outward), causing deformation. As a result, damage such as cracks may occur at the joint between the opening 15 and the lid body 11 (see FIG. 2). If damage occurs at the joint, the airtightness of the joint is lost, and if gas is subsequently discharged from the gas exhaust valve 23 of the energy storage element 20, the gas inside the exterior body 10 will leak from the damaged part. In other words, an unsafe event occurs in which gas leaks from an unexpected place in the exterior body 10. In this regard, in the energy storage device 1 according to the present embodiment, the energy storage element array 24 is restrained by the restraining member 50, and the restraining force of the connecting member 52 is effectively applied to the side of the opening 15, which is the part of the body 12 that is most likely to deform. This suppresses expansion of the energy storage element array 24 in the X-axis direction on the side of the opening 15, thereby reducing the possibility of damaging the joint between the opening 15 and the lid 11. In addition, the restraining force of the lower end of the box-shaped body 12 (particularly the bottom wall 13b (see FIG. 5)) effectively acts on the lower end (the end on the Z-axis negative side) of the pair of end plates 51, which is considered to be most likely to open because it is not connected. In other words, the part of the body 12 with the highest restraining force in the X-axis direction can suppress the opening (displacement outward) of the lower end of the pair of end plates 51. Therefore, the restraining force of the pair of end plates 51, the connecting member 52, and the body 12 effectively acts on the entire energy storage element array 24, thereby suppressing expansion of the energy storage element array 24. In addition, since only one connecting member 52 needs to be provided inside the exterior body 10, the configuration for restraining the energy storage element array 24 can be simplified and the energy storage device 1 can be made smaller. In this way, the energy storage device 1 according to this embodiment can improve safety with a simple configuration.

In addition, in this embodiment, each of the multiple storage elements 20 has a gas exhaust valve 23, and is arranged with the gas exhaust valve 23 facing in the positive direction of the Z axis. The connecting member 52 is arranged in a position facing the gas exhaust valves 23 of the multiple storage elements 20, and has a through hole 52a that penetrates in the positive direction of the Z axis.

In this embodiment, as shown in FIGS. 2 to 4, the gas exhaust valves 23 are arranged in the array direction (X-axis direction) in the storage element array 24 and are located in the center in the width direction (Y-axis direction). The connecting member 52 is arranged in a position facing these gas exhaust valves 23. That is, the pair of end plates 51 are connected to each other at the center in the width direction by the connecting member 52, so that the pair of end plates 51 can apply a restraining force in the X-axis direction to the storage element array 24 in a balanced manner in the width direction. In addition, as shown in FIGS. 3 and 4, the connecting member 52 has a through hole 52a formed in a range facing at least a part of each of the multiple gas exhaust valves 23 in a plan view (when viewed from the side in the Z-axis positive direction). Therefore, the connecting member 52 applies a restraining force in the X-axis direction to the pair of end plates 51, and when any of the storage elements 20 is opened, the gas discharged from the gas exhaust valve 23 can be sent in the Z-axis positive direction. Therefore, the gas discharged from the gas exhaust valve 23 can be efficiently discharged to the outside of the exterior body 10 through the exhaust pipe 90. This, for example, suppresses an increase in the internal pressure of the exterior body 10, and as a result, reduces the possibility of deformation or damage to the exterior body 10 due to an increase in internal pressure. Note that the number of through holes 52a formed in the connecting member 52 corresponding to the multiple gas exhaust valves 23 is not limited to one. For example, multiple through holes 52a may be formed in the connecting member 52 so that the gas exhaust valves 23 and the through holes 52a have a one-to-one relationship.

The above describes the energy storage device 1 according to the embodiment, but the energy storage device 1 may include a restraining member having a configuration different from that shown in Figures 2 to 5. Therefore, below, modified examples of the restraining member included in the energy storage device 1 will be described, focusing on the differences from the above embodiment.

(Modification)
Fig. 6 is a perspective view showing the appearance of a restraining member 50a and an energy storage element array 24 according to an embodiment of a modified example of the embodiment. Fig. 7 is a cross-sectional view of a connecting member 53 according to the embodiment. Fig. 7 shows a schematic cross-section of the connecting member 53 in the YZ plane passing through line VII-VII in Fig. 6, and the approximate arrangement range of the gas release valves 23 of the energy storage elements 20 is indicated by a dotted area.

As shown in FIG. 6, the restraining member 50a according to this modification has a pair of end plates 51 that sandwich the energy storage element array 24 in the X-axis direction. The pair of end plates 51 are connected by a connecting member 53 arranged on the side of the energy storage element array 24 that faces the opening 15 (see FIG. 2), which is the side in the positive direction of the Z-axis, and are not connected on the other side. These configurations are common to the restraining member 50 according to the embodiment. However, the restraining member 50 according to this modification differs from the restraining member 50 according to the embodiment in that the connecting member 53 has a flow path forming portion 53a that forms a flow path 55 for gas discharged from the gas discharge valve 23 of the energy storage element 20.

That is, in this modified example, each of the multiple storage elements 20 has a gas exhaust valve 23 and is arranged in a position in which the gas exhaust valve 23 faces the second direction (Z-axis positive direction). The connecting member 53 is arranged at a position facing the gas exhaust valves 23 of the multiple storage elements 20, and has a flow path forming portion 53a that forms a gas flow path 55 extending in the first direction (X-axis direction). In this modified example, as shown in Figures 6 and 7, the connecting member 53 is long in the X-axis direction and has a box shape with an opening on the side of the gas exhaust valve 23, and its inner surface functions as the flow path forming portion 53a. As a result, a flow path 55 extending in the X-axis direction (direction perpendicular to the paper surface in Figure 7) is formed inside the flow path forming portion 53a. In addition, exhaust ports 53b are provided at both ends of the connecting member 53 in the longitudinal direction (X-axis direction), and the gas exhausted from the gas exhaust valve 23 passes through the flow path forming portion 53a and the exhaust ports 53b, and is further discharged to the outside of the exterior body 10 via the exhaust pipe 90 (see FIG. 1).

According to this configuration, the connecting member 53 applies a restraining force in the X-axis direction to the pair of end plates 51, and when any of the storage elements 20 is opened, the gas discharged from the gas discharge valve 23 can be sent in the arrangement direction of the storage elements 20 (X-axis direction). This makes it possible to efficiently discharge the gas to the outside. This, for example, suppresses an increase in the internal pressure of the exterior body 10, and as a result, reduces the possibility of deformation or damage to the exterior body 10 due to an increase in internal pressure. In addition, since there is no need to use a separate member that forms a gas flow path, this contributes to simplifying or miniaturizing the configuration of the energy storage device 1.

When the connecting member 53 of this modified example is used, the flow path forming portion 19 of the bus bar plate 17 may be used as a portion that houses (covers) the connecting member 53. Even in this case, by positioning the flow path outlet 18 of the bus bar plate 17 at a position opposite the exhaust port 53b of the connecting member 53, the bus bar plate 17 can be positioned so as not to obstruct the flow of gas discharged from the exhaust port 53b.

(Other Modifications)
The power storage device according to the present invention has been described above based on the embodiment and its modified examples. However, the present invention is not limited to the above embodiment and modified examples. As long as the modifications do not deviate from the spirit of the present invention, those having ordinary skill in the art who have made various modifications to the above embodiment or modified examples are also included in the scope of the present invention.

For example, the pair of end plates 51 may be connected by two or more connecting members arranged on the side of the opening 15 in the main body 12 of the exterior body 10. For example, in a plan view, a connecting member may be arranged on each side in the Y-axis direction of the gas exhaust valve 23 of the storage element 20. This allows the pair of end plates 51 to apply a restraining force in the X-axis direction to the storage element array 24 in a balanced manner in the width direction, and does not require a connecting member to be arranged in a position opposite the gas exhaust valve. In this case, the gas flow path can be regulated without relying on the structure of the connecting member.

The exterior housing that houses the energy storage element array 24 and the restraining member 50 does not need to be airtight. For example, the exterior housing may have one or more through holes (openings) in the wall for weight reduction, simplification, or cooling of the energy storage element array 24. Even in this case, if the exterior housing is composed of a main body that houses the energy storage element array 24 and the restraining member 50 and a lid that covers the opening of the main body, deformation or damage to the exterior housing can be suppressed by arranging the connecting member 52 on the side of the opening of the main body.

The restraining member 50 does not have to be made of metal. The restraining member 50 may be made of a highly rigid non-metallic material, such as fiber-reinforced plastic.

In addition, configurations constructed by combining multiple components described above in any desired manner are also included within the scope of the present invention.

The present invention can be applied to a storage device equipped with a storage element such as a lithium-ion secondary battery.

REFERENCE SIGNS LIST 1 Energy storage device 10 Exterior body 11 Lid body 12 Main body 15 Opening 19, 53a Flow path forming portion 20 Energy storage element 21 Container 21a Long side surface 21c Lid plate 22 Electrode terminal 23 Gas exhaust valve 24 Energy storage element array 50, 50a Restraint member 51 End plate 52, 53 Connection member 52a Through hole 53b Exhaust port

Claims (4)

A storage element array including a plurality of storage elements arranged side by side in a first direction;
a pair of end plates sandwiching the energy storage element array in the first direction;
an exterior body having a main body portion that houses the energy storage element array and the pair of end plates,
The main body is formed in a box shape having an opening on a side in a second direction intersecting with the first direction,
the pair of end plates are connected to each other by a connecting member disposed on a side of the energy storage element array in the second direction, and are not connected to each other on a side of the energy storage element array in the other direction;
the connecting member does not have a portion that protrudes in the first direction beyond the end plate on the one side in the first direction of the pair of end plates,
Energy storage device. Each of the plurality of energy storage elements has a gas exhaust valve and is disposed in a position in which the gas exhaust valve faces the second direction,
the connecting member is disposed at a position facing the gas exhaust valves of the plurality of energy storage elements, and has a through hole penetrating in the second direction;
The power storage device according to claim 1. Each of the plurality of energy storage elements has a gas exhaust valve and is disposed in a position in which the gas exhaust valve faces the second direction,
the connecting member is disposed at a position facing the gas exhaust valves of the plurality of energy storage elements, and has a flow path forming portion that forms a gas flow path extending in the first direction;
The power storage device according to claim 1. A storage element array including a plurality of storage elements arranged side by side in a first direction;
a pair of end plates sandwiching the energy storage element array in the first direction;
an exterior body having a main body portion that houses the energy storage element array and the pair of end plates,
The main body is formed in a box shape having an opening on a side in a second direction intersecting with the first direction,
the pair of end plates are connected to each other by a connecting member disposed on a side of the energy storage element array in the second direction, and are not connected to each other on a side of the energy storage element array in the other direction;
The pair of end plates have ends opposite to the second direction in contact with the main body portion in the first direction.
Energy storage device.

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