Power storage module and power storage device

Abstract

To reduce a temperature unevenness of a power storage module.SOLUTION: A power storage module includes a plurality of unit cells. The plurality of unit cells is stacked in a stacking direction. Each of the plurality of unit cells includes a case. The case has a rectangular parallelepiped shape with six outer surfaces. The six outer surfaces include a terminal surface and an opposite surface. The terminal surface indicates an outer surface on which a positive electrode terminal and a negative electrode terminal are provided among the six outer surfaces. The opposite surface indicates an outer surface located opposite the terminal surface. Each of the terminal surface and the opposite surface is parallel to the stacking direction. The plurality of unit cells is arranged in the stacking direction so that the terminal surface and the opposite surface alternate with each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage module and an energy storage device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2014-232735 discloses a structure in an electricity storage module in which, when the internal pressure of a unit cell increases, the space between the unit cells is not blocked and air flows around the unit cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-232735 Summary of the Invention [Problem to be solved by the invention]

[0004] An energy storage module includes multiple unit cells. A unit cell may have a single terminal surface. The "terminal surface" refers to the outer surface of the unit cell on which the terminals are provided. When there is a single terminal surface, both the positive terminal and the negative terminal are provided on one outer surface. When there is a single terminal surface, there is a tendency for the temperature near the terminal surface to become locally high. As a result, there is a possibility that the temperature unevenness of the energy storage module will increase.

[0005] An object of the present disclosure is to reduce temperature unevenness in an electricity storage module. [Means for solving the problem]

[0006] The technical configuration and effects of the present disclosure will be described below. However, the mechanism of action includes speculation. The mechanism of action does not limit the technical scope of the present disclosure.

[0007] 1. The energy storage module includes a plurality of unit cells. The plurality of unit cells are stacked in a stacking direction. Each of the plurality of unit cells includes a case. The case has a rectangular parallelepiped shape with six outer surfaces. The six outer surfaces include a terminal surface and an opposite surface. The terminal surface refers to an outer surface of the six outer surfaces on which a positive terminal and a negative terminal are provided. The opposite surface refers to an outer surface located opposite the terminal surface. The terminal surface and the opposite surface are each parallel to the stacking direction. The plurality of unit cells are lined up in the stacking direction so that the terminal surfaces and the opposite surfaces alternate.

[0008] In a single cell, the opposite side of the terminal side tends to be cooler than the terminal side. By arranging the single cells so that the terminal side and the opposite side alternate, the high temperature points (terminal side) are dispersed within the energy storage module. Furthermore, between adjacent single cells, the terminal side of one single cell is adjacent to the opposite side of the other single cell. It is expected that heat will diffuse from the terminal side of one single cell to the opposite side of the other single cell. The synergistic effect of these actions is expected to reduce temperature unevenness. Hereinafter, an arrangement in which the terminal side and the opposite side are arranged alternately will also be referred to as an "alternate arrangement."

[0009] 2. The energy storage module described in "1" above may include, for example, the following configuration: The six outer surfaces further include four connection surfaces. Each of the four connection surfaces connects a terminal surface to an opposite surface. Of the distances between two outer surfaces facing oppositely among the six outer surfaces, the distance between the terminal surface and the opposite surface is the longest.

[0010] In a single cell, the greater the distance between the terminal surface and the opposite surface, the greater the temperature difference between the terminal surface and the opposite surface. It is believed that the greater the distance between the terminal surface and the opposite surface, the more effective the alternating arrangement.

[0011] 3. The energy storage module according to "1" or "2" above may include, for example, the following configuration: The energy storage module further includes bus bars. The bus bars extend along the stacking direction. The bus bars connect every other two unit cells.

[0012] In an alternating arrangement, every other two single cells may be connected.

[0013] 4. The electricity storage module according to any one of the above items "1" to "3" may include, for example, the following configuration: At least one of a liquid inlet and a gas exhaust valve is provided on the opposite surface.

[0014] 5. The energy storage module described in "4" above may include, for example, the following configuration: A gas release valve is provided on the opposite surface. In a plan view seen from the normal direction of the opposite surface, the bus bar has a shape that does not overlap with the gas release valve.

[0015] If the bus bar overlaps the gas release valve, the gas release valve may be interfered with by the bus bar. If the bus bar does not overlap the gas release valve, the gas release valve can function smoothly.

[0016] 6. The energy storage module described in "3" above may include, for example, the following configuration: A bus bar is disposed between the terminal surfaces and extends across the opposite surface. The bus bar includes a portion that extends away from the opposite surface.

[0017] By extending the bus bar away from the opposite surface, interference of the bus bar with adjacent unit cells can be reduced. The bus bar may be entirely away from the opposite surface, or may be partially away from the opposite surface. The bus bar may be locally away from the opposite surface.

[0018] 7. The energy storage module according to any one of the above items "1" to "3" may include, for example, the following configuration: At least one of the four connection surfaces is provided with at least one of a liquid inlet and a gas release valve.

[0019] 8. The energy storage module described in "3" above may include, for example, the following configuration: In a plan view seen from the normal direction of the opposite surface, the bus bar extends parallel to the stacking direction to connect the two unit cells.

[0020] 9. The energy storage module described in "3" above may include, for example, the following configuration: In a plan view seen from the normal direction of the opposite surface, the bus bar connects the two unit cells by extending in a direction intersecting the stacking direction.

[0021] 10. The energy storage module described in "3" above may include, for example, the following configuration: At least a portion of the bus bar is fixed to the opposite surface.

[0022] In an alternating arrangement, misalignment of the unit cells may occur. Fixing the bus bar to the opposite surface is expected to reduce misalignment. For example, the bus bar may be fixed to the opposite surface with an adhesive or the like.

[0023] 11. The energy storage module described in "3" above may include, for example, the following configuration: In a projection view of the positive electrode terminal, the negative electrode terminal, and the opposite surface projected from the stacking direction onto an imaginary plane perpendicular to the opposite surface, the tips of the positive electrode terminal and the negative electrode terminal are located inside the opposite surface.

[0024] In the projection view of "11" above, the tip of the terminal does not protrude from the opposite surface, which is expected to improve space efficiency.

[0025] 12. The energy storage module described in "11" above may include, for example, the following configuration: In a projection view, the tips of the positive electrode terminal and the negative electrode terminal are in contact with opposite surfaces.

[0026] In the projection view of "11" above, the tip of the terminal is in contact with the opposite surface, which is expected to improve space efficiency.

[0027] 13. The energy storage module described in "11" above may include, for example, the following configuration: The bus bar has a first main surface and a second main surface. The first main surface faces the unit cell. The second main surface is located on the opposite side of the first main surface. When the second main surface, which is on the axis of the positive terminal or the negative terminal, is also projected in a projection view, the second main surface is located inside the opposite surface.

[0028] In the projection diagram of "13" above, the busbars do not protrude from the opposite side, which is expected to improve space efficiency.

[0029] 14. The energy storage module described in "13" above may include, for example, the following configuration: In a projection view, the second main surface is in contact with the opposite surface.

[0030] In the projection diagram of "13" above, the bus bar is in contact with the opposite surface, which is expected to improve space efficiency.

[0031] 15. A power storage device includes the power storage module according to any one of the above items "1" to "14."

[0032] Hereinafter, an embodiment of the present disclosure (hereinafter may be abbreviated as "the present embodiment") will be described. However, the present embodiment does not limit the technical scope of the present disclosure. The present embodiment is illustrative in all respects. The present embodiment is non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the claims. For example, it is also intended from the beginning that any configuration may be extracted from the present embodiment and arbitrarily combined. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a conceptual diagram showing an example of a vehicle according to an embodiment of the present invention. [Figure 2] 1 is a schematic perspective view illustrating an example of a power storage device according to an embodiment of the present invention. [Figure 3] 1 is a first schematic perspective view showing an example of an electricity storage module according to the present embodiment. [Figure 4] FIG. 1 is a schematic perspective view showing an example of a unit cell according to the present embodiment. [Figure 5] FIG. 2 is a schematic plan view illustrating an example of a bus bar according to the present embodiment. [Figure 6] FIG. 2 is a second schematic perspective view showing an example of the electricity storage module according to the present embodiment. [Figure 7] 1 is a first schematic cross-sectional view showing an example of a bus bar according to the present embodiment. [Figure 8] FIG. 4 is a second schematic cross-sectional view showing an example of a bus bar according to the present embodiment. [Figure 9] FIG. 2 is a first projection view in this embodiment. [Figure 10] FIG. 2 is a second projection view in this embodiment. [Figure 11] FIG. 2 is a conceptual diagram showing an example of a terminal structure in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0034] -Key terms- "Comprise," "include," "have," and variations thereof are open-ended terms. Open-ended terms may or may not include additional elements in addition to the required elements. "Consisting of" is a closed term. However, even a structure expressed in closed terminology may include additional elements that are normally associated with the technology or that are unrelated to the technology in question. "Consisting essentially of..." is a semi-closed term. Semi-closed terminology allows for the addition of elements that do not substantially affect the basic and novel characteristics of the technology in question.

[0035] Expressions such as "may" and "may" are used in the permissive sense, meaning "to have the possibility," rather than in the obligatory sense, meaning "to have to."

[0036] Geometric terms should not be interpreted in a strict sense. Examples of geometric terms include "parallel," "perpendicular," and "orthogonal." For example, directions, angles, distances, and the like may be displaced relative to one another as long as substantially the same or similar functions are obtained. Geometric terms may include, for example, tolerances, errors, and the like in design, work, and manufacturing. The dimensional relationships in each figure may not match the actual dimensional relationships. The dimensional relationships in each figure may be changed to aid the reader's understanding. For example, length, width, thickness, and the like may be changed. Some components may be omitted.

[0037] A "rectangular parallelepiped shape" has six outer surfaces. The planar shape of each outer surface may be, for example, rectangular or square. Expressions such as "rectangular parallelepiped," "rectangular," and "square" indicate that the shape does not necessarily have to be a strict rectangular parallelepiped, rectangle, square, or the like. For example, each outer surface does not have to be flat. For example, the outer surface may be curved inward or outward. For example, each corner may be rounded. For example, each side does not have to be straight. For example, the outer surfaces do not have to be perpendicular to each other at their junctions. For example, the junctions (edges, corners) between the outer surfaces may be rounded. For example, if the junctions between the outer surfaces are rounded, the boundary between the outer surfaces may not be clear. For example, a weld bead or the like may be formed at the junction between the outer surfaces. For example, the areas of two outer surfaces facing opposite each other may be different. The rectangular parallelepiped shape includes a "cubic shape," a "quadratic prism shape," etc. The cubic shape and the quadratic prism shape do not necessarily have to be a strict cube or a quadratic prism.

[0038] Terms expressing relative or absolute positioning, such as "contact," "flush," and "identical," are not limited to strictly expressing such positioning. These terms also express states that include tolerances, errors, and the like. For example, the positions of objects may be displaced relative to one another as long as substantially the same or similar functions are obtained. Note that in a projection drawing, "a mode in which an object fits inside a surface" includes "a mode in which an object contacts a surface."

[0039] Elements described in the "singular" may also include the plural unless otherwise specified. For example, a single cell may refer to a plurality of single cells (single cells).

[0040] "At least one of A and B" includes "A" only, "B" only, and "both A and B." "At least one of A and B" can also be written as "A and / or B."

[0041] "Case width" refers to the outer dimension in the W direction. "Case height" refers to the outer dimension in the H direction. "Case thickness" refers to the outer dimension in the T direction. The W direction, H direction, and T direction may be perpendicular to one another. The H direction may be, for example, parallel to the vertical direction, or may be non-parallel. The H direction may be, for example, parallel to the vehicle's traveling direction, or may be non-parallel. The T direction may be, for example, parallel to the vehicle's traveling direction, or may be non-parallel.

[0042] In this embodiment, a power storage device and a power storage module for a vehicle will be described. However, the use for a vehicle is merely one example of the application, and the application is arbitrary.

[0043] The term "terminal" is a general term for a "positive electrode terminal" and a "negative electrode terminal." The term "terminal" refers to at least one of a positive electrode terminal and a negative electrode terminal.

[0044] -vehicle- FIG. 1 is a conceptual diagram showing an example of a vehicle in this embodiment. The vehicle 1 may be, for example, a BEV (Battery Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle). The vehicle 1 includes a power storage device 10. The power storage device 10 may be mounted in any position. For example, the power storage device 10 may be disposed under the floor of the vehicle 1.

[0045] -Electricity storage device- FIG. 2 is a schematic perspective view showing an example of a power storage device according to this embodiment. The power storage device 10 includes a power storage module 11. The power storage device 10 may include a plurality of power storage modules 11. The power storage device 10 may include, for example, one to four power storage modules 11. The power storage device 10 may further include, for example, a storage case 20 and a cooler 30. The storage case 20 stores the power storage modules 11. The storage case 20 may include an upper case 21 and a lower case 22. There may be a gap between the power storage modules 11. For example, a partition plate (not shown) may be provided between the power storage modules 11. The cooler 30 may be arranged on the upper case 21 side or the lower case 22 side. The cooler 30 can cool the power storage modules 11. The cooler 30 may include, for example, a refrigerant flow path.

[0046] -Energy storage module- FIG. 3 is a first schematic perspective view showing an example of a power storage module according to this embodiment. The power storage module 11 includes a plurality of unit cells 100. The unit cells 100 may be electrically connected in series or in parallel. A series connection is shown as an example. The number of unit cells 100 is arbitrary as long as it is two or more. The number of unit cells 100 may be, for example, 2 to 200, 10 to 150, or 50 to 100.

[0047] Single cell FIG. 4 is a schematic perspective view showing an example of a unit cell in this embodiment. The unit cell 100 is the smallest unit constituting the power storage device 10. The unit cell 100 may be, for example, a lithium ion battery. Each of the multiple unit cells 100 includes a case 101. The case 101 houses a power generating element (not shown). The power generating element may be of a laminated type or a wound type. The power generating element includes, for example, a positive electrode active material, a negative electrode active material, and an electrolyte. The positive electrode active material may include, for example, lithium iron phosphate, lithium nickel composite oxide, or the like. The negative electrode active material may include, for example, graphite, silicon oxide, silicon, or the like. The electrolyte may be liquid, gel, or solid.

[0048] ·case The case 101 may be made of, for example, metal. The case 101 may be made of, for example, an aluminum alloy. The case 101 has a rectangular parallelepiped shape. The case 101 may be in the form of, for example, a long plate. The width of the case 101 may be, for example, 500 mm or more, 750 mm or more, or 1000 mm or more. The width of the case 101 may be, for example, 2000 mm or less, 1500 mm or less, or 1250 mm or less. The height of the case 101 may be, for example, 50 mm or more, 75 mm or more, or 100 mm or more. The height of the case 101 may be, for example, 200 mm or less, 150 mm or less, 125 mm or less, or 100 mm or less. The thickness of the case 101 may be, for example, 5 mm or more, 10 mm or more, 15 mm or more, or 20 mm or more. The thickness of case 101 may be, for example, 30 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, or 10 mm or less.

[0049] The ratio of width to height may be, for example, 5 to 20. The ratio of width to thickness may be, for example, 50 to 200.

[0050] Terminal surface, opposite surface, connection surface The case 101 has six outer surfaces. The six outer surfaces are made up of a terminal surface 101a, an opposite surface 101b, and four connection surfaces 101c. That is, the single cell 100 has a single terminal surface 101a. The terminal surface 101a is provided with both a positive electrode terminal 110 and a negative electrode terminal 120. Each of the positive electrode terminal 110 and the negative electrode terminal 120 is electrically connected to a power generating element (not shown) inside the case 101. The opposite surface 101b is located opposite the terminal surface 101a. Each of the four connection surfaces 101c connects the terminal surface 101a and the opposite surface 101b.

[0051] For example, the four connection surfaces 101c may form a cylindrical case body. For example, the four connection surfaces 101c may be one piece, or may be assembled from four plates. For example, the case body may be a rectangular tube. For example, the terminal surface 101a and the opposite surface 101b may each form a lid. The lid may close an opening of the case body. For example, the lid and the case body may be joined by laser welding.

[0052] For example, the four connection surfaces 101c and the opposite surface 101b may form the case body. For example, the case body may be a container having a bottom surface. For example, the case body may be a rectangular cylindrical container with a bottom. The case body may have an opening on the side opposite the bottom surface. The terminal surface 101a may form a lid. The lid may close the opening of the case body.

[0053] At least one of the four connection surfaces 101c may have the largest area among the six outer surfaces. For example, a single connection surface 101c may have the largest area. For example, two connection surfaces 101c facing opposite each other may have the largest area. For example, all four connection surfaces 101c may have the same largest area. Alternatively, at least one of the four connection surfaces 101c may have the smallest area among the six outer surfaces. Alternatively, at least one of the four connection surfaces 101c may have an area intermediate between the largest area and the smallest area.

[0054] For example, terminal surface 101a may have the smallest area of ​​the six outer surfaces. For example, terminal surface 101a may have the largest area of ​​the six outer surfaces. For example, terminal surface 101a may have an area intermediate between the largest area and the smallest area. For example, opposite surface 101b may have the same area as terminal surface 101a, or may have a different area.

[0055] For example, among the six outer surfaces, the distance between two outer surfaces facing opposite each other may be the longest, the distance between terminal surface 101a and the opposite surface 101b. For example, the distance between terminal surface 101a and the opposite surface 101b may be the shortest. For example, the distance between terminal surface 101a and the opposite surface 101b may be an intermediate distance between the maximum distance and the minimum distance. For example, the distance between connection surfaces 101c may be the longest. For example, the distance between connection surfaces 101c may be the shortest. For example, the distance between connection surfaces 101c may be an intermediate distance between the maximum distance and the minimum distance. For example, as shown in FIG. 4, the distance between terminal surface 101a and the opposite surface 101b may indicate the outer dimension (width) in the W direction. For example, the distance between connection surfaces 101c may indicate the outer dimension (thickness) in the T direction. For example, the distance between connection surfaces 101c may indicate the outer dimension (height) in the H direction. In addition, if the distance between two outer surfaces is not constant, the distance between the two outer surfaces shall indicate the shortest distance between the two surfaces.

[0056] Liquid inlet, gas exhaust valve For example, at least one of the liquid inlet 130 and the gas release valve 140 may be provided on the opposite surface 101b. For example, when assembling the single cell 100, an electrolytic solution (liquid electrolyte) can be injected into the case 101 through the liquid inlet 130. The liquid inlet 130 may be blocked by, for example, a sealing plug (not shown). For example, when the internal pressure of the case 101 increases, gas can be released through the gas release valve 140. Alternatively, at least one of the liquid inlet 130 and the gas release valve 140 may be provided on at least one of the four connection surfaces 101c. Alternatively, at least one of the liquid inlet 130 and the gas release valve 140 may be provided on the terminal surface 101a. On the terminal surface 101a, the liquid inlet 130 and the gas release valve 140 may be disposed, for example, between the positive electrode terminal 110 and the negative electrode terminal 120.

[0057] Alternating arrangement The plurality of unit cells 100 are stacked in the stacking direction (T direction). The terminal surfaces 101a and the opposite surfaces 101b are parallel to the stacking direction. The unit cells 100 may be in close contact with each other in the stacking direction. There may be gaps between the unit cells 100 in the stacking direction. The plurality of unit cells 100 are arranged in an alternating manner in the stacking direction. That is, as shown in FIG. 3, the plurality of unit cells 100 are arranged in the stacking direction so that the terminal surfaces 101a and the opposite surfaces 101b are staggered. This alternating arrangement is expected to reduce temperature unevenness. The orientation of the unit cells 100 in the H direction may be staggered as shown in FIG. 3, or may be uniform as shown in FIG. 6.

[0058] The energy storage module 11 may have, for example, a single arrangement pattern. That is, in the energy storage module 11, all of the unit cells 100 may be arranged in an alternating arrangement. As long as the energy storage module 11 includes an alternating arrangement, the energy storage module 11 may include a plurality of arrangement patterns. For example, the arrangement pattern may change at the end of the stacking direction. Of the unit cells 100 included in the energy storage module 11, for example, 50% or more, 80% or more, or 90% or more of the unit cells 100 may be arranged in an alternating arrangement.

[0059] Busbar As shown in FIG. 3, the energy storage module 11 may further include a bus bar 150. The bus bar 150 may extend, for example, along the stacking direction (T direction). In the stacking direction, the bus bar 150 may connect every other two unit cells 100. The bus bar 150 may be made of metal, for example. The bus bar 150 may be plate-shaped, for example. The bus bar 150 may have a hole. The bus bar 150 may be connected to a terminal by inserting the terminal into the hole. For example, the bus bar 150 may be welded to an end surface of the terminal.

[0060] For example, in FIG. 3, the W direction is the normal direction to the opposite surface 101b. For example, as shown in FIG. 3, in a plan view seen from the normal direction to the opposite surface 101b, the bus bar 150 may connect two unit cells 100 by extending, for example, parallel to the stacking direction (T direction). The bus bar 150 may extend, for example, linearly. The bus bar 150 may extend, for example, in a curved manner. The bus bar 150 may be bent, for example.

[0061] 3, in a plan view seen from the normal direction of opposite surface 101b, bus bar 150 may have a shape that does not overlap with gas release valve 140. When bus bar 150 does not overlap with gas release valve 140, gas release valve 140 can function smoothly without being interfered with by bus bar 150.

[0062] The bus bar 150 may have a shape that overlaps with the liquid injection hole 130. That is, the liquid injection hole 130 may be disposed directly below the bus bar 150.

[0063] Fig. 5 is a schematic plan view showing an example of a bus bar in this embodiment. Fig. 5 shows a plan view seen from the normal direction of the opposite surface 101b. For example, the bus bar 150 may be curved or bent in an in-plane direction so as not to overlap with the gas release valve 140. The in-plane direction in Fig. 5 refers to a direction that does not go out of the plane of Fig. 5. The in-plane direction in Fig. 5 includes the T direction and the H direction.

[0064] Fig. 6 is a second schematic perspective view showing an example of the energy storage module of this embodiment. In Fig. 6, the W direction is the normal direction to the opposite surface 101b. For example, as shown in Fig. 6, in a plan view seen from the normal direction to the opposite surface 101b, the bus bar 150 may extend in a direction intersecting the stacking direction (T direction) to connect two unit cells 100.

[0065] FIG. 7 is a first schematic cross-sectional view illustrating an example of a busbar according to this embodiment. As illustrated in FIG. 7, the busbar 150 may extend across the opposite surface 101b disposed between the terminal surfaces 101a. For example, the busbar 150 may be curved in an out-of-plane direction. The out-of-plane direction in FIG. 7 indicates a direction intersecting the T direction in the plane of FIG. 7. The out-of-plane direction in FIG. 7 includes the W direction. That is, the busbar 150 may have a portion extending away from the opposite surface 101b. By forming a gap between the busbar 150 and the opposite surface 101b, for example, the gas release valve 140 may function without being interfered with by the busbar 150. The busbar 150 may have a bridge shape, for example. The busbar 150 may be formed in an arc shape, for example. The busbar 150 may be curved in a parabolic shape, for example. The busbar 150 may be curved in a U shape, for example. The bus bar 150 may be bent, for example, in a V shape.

[0066] 8 is a second schematic cross-sectional view showing an example of a busbar according to this embodiment. As shown in FIG. 8, busbar 150 may be bent out of plane to form a convex shape. As described above, opposite surface 101b, which is disposed between terminal surfaces 101a, may be provided with liquid injection hole 130, gas release valve 140, etc.

[0067] At least a portion of the bus bar 150 may be fixed to the opposite surface 101b. For example, the bus bar 150 may be fixed to the opposite surface 101b by a fixing member 151. The fixing member 151 may have electrical insulation properties. The fixing member 151 may contain, for example, an adhesive. The adhesive may contain, for example, an epoxy resin, an acrylic resin, or the like. For example, if the bus bar 150 connects every other two unit cells 100, there is a possibility that the unit cells 100 may become misaligned. Fixing the bus bar 150 to the opposite surface 101b is expected to reduce the misalignment.

[0068] FIG. 9 is a first projection view of this embodiment. In the first projection view, the positive electrode terminal 110, the negative electrode terminal 120, and the opposite surface 101b are projected from the stacking direction (T direction) onto a virtual plane perpendicular to the opposite surface 101b. For example, in the first projection view, the tips of the positive electrode terminal 110 and the negative electrode terminal 120 may be contained within the opposite surface 101b. In the first projection view, the tips of the terminals do not protrude from the opposite surface 101b, which is expected to improve space efficiency. For example, in the first projection view, the tips of the terminals may be in contact with the opposite surface 101b. In the first projection view, the tips of the terminals are in contact with the opposite surface 101b, which is expected to improve space efficiency.

[0069] FIG. 10 is a second projection view of this embodiment. The second projection view shows the bus bar 150 projected from the stacking direction onto a virtual plane of the first projection view. The dashed-dotted line in the second projection view indicates the axis of the terminal. The bus bar 150 may have a first main surface 150a and a second main surface 150b. The first main surface 150a faces the single cell 100. The second main surface 150b is located on the opposite side of the first main surface 150a. For example, in the second projection view, the second main surface 150b, which is located on the axis of the terminal, may be located inside the opposite surface 101b. In the second projection view, the second main surface 150b does not protrude from the opposite surface 101b, which is expected to improve space efficiency. For example, the bus bar 150 connected to the positive electrode terminal 110 may be located inside the opposite surface 101b. For example, bus bar 150 connected to negative terminal 120 may be located inside opposite surface 101b. For example, both bus bar 150 connected to positive terminal 110 and bus bar 150 connected to negative terminal 120 may be located inside opposite surface 101b.

[0070] For example, in the second projection view, the second main surface 150b may be in contact with the opposite surface 101b. By having the second main surface 150b in contact with the opposite surface 101b in the second projection view, it is expected that space efficiency will be improved. By having the second main surface 150b in contact with the opposite surface 101b in the second projection view, the second main surface 150b can be flush with the opposite surface 101b. "Flush" indicates that the two surfaces are substantially on the same plane. Therefore, for example, it is considered that the outer frames of the energy storage modules 11 will be aligned.

[0071] ·Terminal structure FIG. 11 is a conceptual diagram showing an example of an end structure in this embodiment. At the end in the stacking direction (T direction), the terminal of the unit cell 100 may be electrically connected to, for example, the storage case 20. For example, both types of unit cells 200 may be arranged at the end of the energy storage module 11. Both types of unit cells 200 have two terminal surfaces. The two terminal surfaces face opposite each other. A positive terminal 110 is provided on one terminal surface. A negative terminal 120 is provided on the other terminal surface. By arranging both types of unit cells 200 at the ends in the stacking direction, a plurality of unit cells 100 can be connected in series. Alternatively, the unit cells 100 at both ends may be connected to each other by a long bus bar (not shown).

[0072] A plurality of unit cells 100 may form a single row. A plurality of unit cells 100 may form, for example, two or more rows. When a plurality of unit cells 100 form multiple rows, the rows may be electrically connected in parallel or in series. The rows may be arranged, for example, in parallel. The number of unit cells 100 constituting one row may be, for example, 2 to 50. [Explanation of symbols]

[0073] 1 vehicle, 10 energy storage device, 11 energy storage module, 20 storage case, 21 upper case, 22 lower case, 30 cooler, 100, 200 single cell, 101 case, 101a terminal surface, 101b opposite surface, 101c connection surface, 110 positive electrode terminal, 120 negative electrode terminal, 130 liquid injection hole, 140 gas discharge valve, 150 bus bar, 150a first main surface, 150b second main surface, 151 fixing member.

Claims

1. It includes a plurality of single cells, The plurality of unit cells are stacked in a stacking direction, Each of the plurality of unit cells includes a case; The case has a rectangular parallelepiped shape with six outer surfaces, The six outer surfaces include a terminal surface and an opposite surface; The terminal surface indicates an outer surface on which a positive electrode terminal and a negative electrode terminal are provided, among the six outer surfaces, the opposite surface refers to the outer surface located opposite the terminal surface; The terminal surface and the opposite surface are each parallel to the stacking direction, and The plurality of unit cells are arranged in the stacking direction so that the terminal surfaces and the opposite surfaces are alternately arranged. Energy storage module.

2. The six outer surfaces further include four connecting surfaces; Each of the four connection surfaces connects the terminal surface and the opposite surface, Among the six outer surfaces, the distance between two of the outer surfaces facing opposite to each other is the longest, and The energy storage module according to claim 1 .

3. further comprising a bus bar; The bus bar extends along the stacking direction, and The bus bars connect every other two of the unit cells. The energy storage module according to claim 1 or 2.

4. At least one of a liquid inlet and a gas exhaust valve is provided on the opposite surface. The energy storage module according to claim 3 .

5. The gas exhaust valve is provided on the opposite surface, and the bus bar has a shape that does not overlap with the gas release valve in a plan view seen from a normal direction of the opposite surface, The electricity storage module according to claim 4 .

6. the bus bar extends across the opposite surface disposed between the terminal surfaces, and the bus bar includes a portion extending away from the opposite surface; The energy storage module according to claim 3 .

7. At least one of the four connection surfaces is provided with at least one of a liquid inlet and a gas exhaust valve. The energy storage module according to claim 2 .

8. In a plan view seen from the normal direction of the opposite surface, The bus bar extends parallel to the stacking direction to connect two of the unit cells. The energy storage module according to claim 3 .

9. In a plan view seen from the normal direction of the opposite surface, The bus bar extends in a direction intersecting the stacking direction to connect two of the unit cells. The energy storage module according to claim 3 .

10. At least a portion of the bus bar is fixed to the opposite surface. The energy storage module according to claim 3 .

11. In a projection view of the positive electrode terminal, the negative electrode terminal, and the opposite surface projected from the stacking direction onto a virtual plane orthogonal to the opposite surface, tips of the positive electrode terminal and the negative electrode terminal are contained inside the opposite surface. The energy storage module according to claim 3 .

12. In the projection view, the tip ends of the positive electrode terminal and the negative electrode terminal are in contact with the opposite surface. The energy storage module according to claim 11.

13. the bus bar has a first main surface and a second main surface; the first main surface faces the single cell, the second major surface is located opposite the first major surface, and When the second main surface, which is on the axis of the positive electrode terminal or the negative electrode terminal, is also projected onto the projection view, the second main surface is located inside the opposite surface. The energy storage module according to claim 11.

14. In the projection view, the second main surface is in contact with the opposite surface. The energy storage module according to claim 13.

15. A storage battery module comprising the energy storage module according to claim 1. Energy storage device.

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