Power storage device

Abstract

To provide a power storage device having an exterior body with improved reliability.SOLUTION: A power storage device includes a power storage element 100 and an exterior body that houses the power storage element, and the exterior body includes an exterior body main body 11 having an opening 13 that forms an opening in a first direction, and a lid body 50 that covers the opening, and the exterior body main body is disposed in the opening and has a protrusion 16 that protrudes in the first direction, and the lid body includes a through hole 52, and the protrusion is inserted into the through hole, and includes a welded portion 17 that is welded to the lid body.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electricity storage device. [Background technology]

[0002] Patent Document 1 discloses a battery pack. The battery pack includes a battery module and a housing that houses the battery module. The housing has a main body portion with an opening, and a plate-shaped lid member fixed to the main body portion so as to cover the opening. The main body portion has a bottom wall and an upper wall that faces the bottom wall and has an opening. The lid member has a plurality of through holes. Each of the plurality of through holes is provided at a position that overlaps with a screw hole provided in the upper wall. A bolt is inserted into each of the plurality of through holes, and the bolt is fastened to the screw hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-168300 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional battery pack, the cover member is fixed to the main body by only a number of bolts. Therefore, for example, loosening of one bolt leads to a decrease in the fixing force of the cover member to the main body. This decrease in fixing force may allow foreign matter to enter the inside of the housing.

[0005] The present invention was made by the present inventors by newly focusing on the above-mentioned problems, and has an object to provide an electricity storage device including an exterior body with improved reliability. [Means for solving the problem]

[0006] An energy storage device according to one embodiment of the present invention comprises an energy storage element and an exterior body that houses the energy storage element, the exterior body comprising an exterior body main body having an opening that forms an opening in a first direction, and a lid body that covers the opening, the exterior body main body being positioned at the opening and comprising a protrusion that protrudes in the first direction, the lid body having a through hole, the protrusion being inserted into the through hole, and comprising a welded portion welded to the lid body. Effect of the Invention

[0007] According to the present invention, it is possible to provide an electricity storage device including an exterior body with improved reliability. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. [Diagram 3] FIG. 3 is an enlarged perspective view of a protruding portion according to the embodiment. [Figure 4] FIG. 4 is a plan view showing the configuration of the protrusion and its surroundings according to the embodiment. [Diagram 5] FIG. 5 is a cross-sectional view showing a configuration of a protrusion and its surroundings according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a configuration of a protrusion and its surroundings according to the first modification of the embodiment. [Figure 7] FIG. 7 is an enlarged perspective view of a protrusion according to the second modification of the embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing a configuration of a protrusion and its surroundings according to the second modification of the embodiment. [Figure 9] FIG. 9 is an enlarged perspective view of a protrusion according to the third modification of the embodiment. [Figure 10] FIG. 10 is a side view showing a convex portion and a protruding portion according to the third modification of the embodiment. [Figure 11] FIG. 11 is a perspective view showing a configuration of a protrusion and its surroundings according to the third modification of the embodiment. [Figure 12] FIG. 12 is a cross-sectional view showing a protrusion that does not pass through a through hole provided in a lid body and the configuration around the protrusion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (1) An energy storage device according to one embodiment of the present invention comprises an energy storage element and an exterior body that houses the energy storage element, the exterior body comprising an exterior body main body having an opening that forms an opening in a first direction, and a lid body that covers the opening, the exterior body main body being disposed at the opening and comprising a protrusion that protrudes in the first direction, the lid body having a through hole, the protrusion being inserted into the through hole, and comprising a welded portion welded to the lid body.

[0010] According to the energy storage device described in (1) above, when the lid is placed on the exterior body, the protrusion provided on the exterior body is inserted into the through hole of the lid, so that the lid can be positioned efficiently or accurately. The protrusion is further welded to the lid at least at the welded portion. Therefore, the protrusion can also serve to fix the lid to the exterior body. In this way, the energy storage device according to this aspect is an energy storage device equipped with a highly reliable exterior body.

[0011] (2) In the energy storage device described above in (1), the welded portion may cover the through hole when viewed from the first direction.

[0012] According to the electricity storage device described in (2) above, the welded portion of the protrusion can cover the through hole formed in the lid from the outside of the lid. This makes the through hole more reliably sealed. In other words, the hermeticity of the through hole against gas or liquid is improved.

[0013] (3) In the energy storage device described above in (1) or (2), the opening may have an opening end surface facing the lid body, and the opening end surface may have a joint portion that is joined to the lid body.

[0014] According to the electricity storage device described in (3) above, the bonding area between the lid and the exterior body includes at least the bonding area between the opening end face and the lid and the bonding area between the welding portion of the protrusion and the lid, so that the lid and the exterior body are bonded more firmly.

[0015] (4) In the energy storage device described above in (3), the protruding portion may be adjacent to the joint portion when viewed from the first direction.

[0016] According to the electricity storage device described in (4) above, when viewed from the first direction, it is easy to make the joint and the welded part continuous or overlap each other, which makes it easier to maintain hermeticity against gas or liquid, for example, in the vicinity of the protruding part of the exterior body.

[0017] (5) In the power storage device according to any one of (1) to (4) above, the protrusions may be arranged along a second direction perpendicular to the first direction.

[0018] According to the energy storage device described in (5) above, for example, by increasing the number of protrusions, the bonding area between the lid and the exterior body can be increased. Therefore, the number and layout of the protrusions can be appropriately determined according to the specifications required for the exterior body.

[0019] (6) In the electricity storage device according to any one of (1) to (5) above, the protrusion may be connected to an inner circumferential surface of the opening.

[0020] According to the energy storage device described in (6) above, the through hole of the lid is provided at a position overlapping with the opening of the exterior body (internal space of the exterior body main body) when viewed from the first direction, which allows the lid to be made smaller than when the through hole of the lid is provided outside the opening when viewed from the first direction.

[0021] Hereinafter, a description will be given of a power storage device (including its modified examples) according to an embodiment of the present invention with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection of the components, manufacturing processes, and the order of the manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, the dimensions and the like are not strictly illustrated in each drawing. Furthermore, the same reference numerals are used for the same or similar components in each drawing.

[0022] In the following description and drawings, the X-axis direction is defined as the arrangement direction of a pair of terminals in one energy storage element, or the opposing direction of a pair of short side surfaces in one energy storage element. The Y-axis direction is defined as the arrangement direction of multiple energy storage elements, the opposing direction of a pair of long side surfaces in one energy storage element, or the thickness direction of the energy storage element. The Z-axis direction is defined as the arrangement direction of the container body and the cover plate in the container of the energy storage element, the arrangement direction of the exterior body and the cover in the exterior body, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect with each other (orthogonal in this embodiment). Note that, depending on the mode of use, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the following description will be given assuming that the Z-axis direction is the up-down direction.

[0023] In the following description, for example, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the opposite direction to the positive X-axis direction. When simply referring to the X-axis direction, it refers to both or either of the positive and negative X-axis directions. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the directions or attitudes are not strictly speaking the same. For example, two directions being parallel not only means that the two directions are completely parallel, but also means that the directions are substantially parallel, that is, that there is a difference of, for example, about several percent. Furthermore, in the following description, when the word "insulation" is used, it means "electrical insulation". An insulating material has a volume resistivity of 1×10 10 It is preferable that the material used is one having a resistance of Ωm or higher.

[0024] (Embodiment) [1. General description of the power storage device] First, an outline of the configuration of the energy storage device 1 in the present embodiment will be described. Fig. 1 is a perspective view showing the external appearance of the energy storage device 1 according to the embodiment. Fig. 2 is an exploded perspective view of the energy storage device 1 according to the embodiment. In Fig. 2, the protrusion 16 is shown in a state before the welded portion 17 is formed. Inside the exterior body 10, in addition to the members shown in Fig. 2, a bus bar and the like are housed, and further, spacers arranged along the energy storage elements 100, restraining members for restraining the plurality of energy storage elements 100, and the like may be arranged. However, illustration and description of these members are omitted.

[0025] The power storage device 1 is a device that can be charged with electricity from the outside and can discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. The rectangular parallelepiped here is a hexahedron with all faces formed of rectangles or squares. The power storage device 1 is, for example, a battery module (battery pack) used for power storage or power supply. Specifically, the power storage device 1 is used as a battery for driving or starting an engine of a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV: Automatic Guided Vehicle), or a railway vehicle for an electric railway. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of the above-mentioned railway vehicles for an electric railway include electric trains, monorails, linear motor cars, and hybrid electric trains equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0026] 1 and 2, the energy storage device 1 includes an exterior body 10 and an energy storage element unit 101 having one or more energy storage elements 100. The energy storage element unit 101 is housed in the exterior body 10. The exterior body 10 is a box-shaped (approximately rectangular parallelepiped) container (module case) that constitutes the housing of the energy storage device 1. In other words, the exterior body 10 is disposed outside the energy storage element unit 101 and protects the energy storage element unit 101. The exterior body 10 is formed from 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), polyethersulfone (PES), polyamide (PA), ABS resin, or a composite material thereof. The exterior body 10 thereby prevents the energy storage element 100 and the like from coming into contact with external metal members and the like.

[0027] The exterior body 10 includes an exterior body main body 11 and a lid body 50. The exterior body main body 11 is a bottomed rectangular cylindrical housing including an opening 13 that forms an opening 13a. The opening 13 is provided at an end of the exterior body main body 11 in the positive direction of the Z axis, and the opening 13a formed by the opening 13 is oriented in the positive direction of the Z axis. The positive direction of the Z axis is an example of a first direction. More specifically, as shown in FIG. 2, the exterior body main body 11 includes a pair of side wall portions 14 that face each other in the X axis direction and a pair of side wall portions 15 that face each other in the Y axis direction. In this embodiment, the opening 13 is formed by the ends (hereinafter simply referred to as "upper ends") of the pair of side wall portions 14 and the pair of side wall portions 15 in the positive direction of the Z axis. Each of the X axis direction and the Y axis direction is an example of a second direction.

[0028] The lid 50 is a member that closes the opening 13a of the exterior body 11. A pair of external terminals 90, a positive electrode and a negative electrode, are arranged on the lid 50. The electricity storage device 1 charges with electricity from the outside and discharges electricity to the outside via the pair of external terminals 90. The external terminals 90 are formed of a conductive member made of a metal such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0029] After the energy storage element unit 101 and the like are housed in the exterior body main body 11, the lid body 50 is fixed to the exterior body main body 11. Specifically, a welding portion 17 (see FIG. 1) formed on a protruding portion 16 (see FIG. 2) of the exterior body main body 11 is welded to the lid body 50. In this embodiment, the opening end face 13b (see FIG. 2), which is an end face of the opening 13 of the exterior body main body 11, is further joined to the lid body 50. In this embodiment, the opening end face 13b is joined to the lid body 50 by thermal welding. This makes it possible to maintain a high level of hermeticity against gas or liquid between the lid body 50 and the exterior body main body 11. The configuration of the protruding portion 16 of the exterior body 10 and its surroundings will be described later with reference to FIGS. 3 to 5.

[0030] The energy storage element unit 101 includes one or more energy storage elements 100. The energy storage element unit 101 according to this embodiment includes eight energy storage elements 100. The eight energy storage elements 100 are arranged in the Y-axis direction with their long side surfaces 110a facing the Y-axis direction. The energy storage element unit 101 may include a spacer or holder (not shown) arranged along the energy storage elements 100. The energy storage element unit 101 may include a bus bar holder that holds a bus bar connected to the energy storage elements 100. The energy storage element unit 101 may include a restraining member (not shown) that restrains the multiple storage elements 100 in the arrangement direction. The eight energy storage elements 100 included in the energy storage element unit 101 are connected in series, for example, by multiple bus bars (not shown), but the electrical connection mode is not limited thereto. There is also no particular limitation on the number of energy storage elements 100 included in the energy storage element unit 101. The number of energy storage elements 100 included in the energy storage element unit 101 may be any number from 1 to 7, or may be 9 or more.

[0031] The energy storage element 100 is a secondary battery, more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. As shown in FIG. 2, the energy storage element 100 includes a container 110 having a flat rectangular parallelepiped (rectangular) shape. An electrode body, a current collector, an electrolyte, and the like (not shown) are accommodated inside the container 110. As the electrode body, for example, a wound type formed by winding an electrode plate and a separator, a laminated type (stack type) formed by stacking a plurality of flat electrode plates, or a bellows type electrode body in which an electrode plate is folded in a bellows shape is adopted. The type of electrolyte accommodated in the container 110 is not particularly limited as long as it does not impair the performance of the energy storage element 100, and various types can be selected. The energy storage element 100 may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 100 may be a primary battery. The energy storage element 100 may be a pouch-type energy storage element. The energy storage element 100 may be a battery using a solid electrolyte. The shape of the energy storage element 100 is not limited to the above-mentioned rectangular shape, and may be other shapes such as a polygonal column shape, a cylindrical shape, an elliptical column shape, or an oblong column shape.

[0032] 2, the container 110 is a rectangular parallelepiped case having a pair of long side surfaces 110a, a pair of short side surfaces 110b, a bottom surface 110d, and a terminal arrangement surface 110c. A pair of terminals 120 and a gas exhaust valve 105 are provided on the terminal arrangement surface 110c. After an electrode body and the like are accommodated inside the main body (container main body) of the container 110, the inside of the container 110 is sealed by welding the container main body and a cover plate forming the terminal arrangement surface 110c. The material of the container 110 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

[0033] The terminal 120 is electrically connected to the electrode body accommodated in the container 110, and is provided protruding from the terminal arrangement surface 110c. One of the pair of terminals 120 is electrically connected to the positive electrode of the electrode body, and the other is electrically connected to the negative electrode of the electrode body. The terminal 120 is formed of a conductive material such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0034] [2. Configuration of protruding portion 16 and its surroundings] Next, the configuration of the protrusion 16 and its periphery according to the embodiment will be described with reference to Figs. 3 to 5 in addition to Figs. 1 and 2 described above. Fig. 3 is an enlarged perspective view of the protrusion 16 according to the embodiment. Fig. 3 illustrates the protrusion 16 in a state before the welded portion 17 is formed. Fig. 4 is a plan view (viewed from the Z-axis positive direction) illustrating the protrusion 16 and its periphery according to the embodiment. Fig. 5 is a cross-sectional view illustrating the protrusion 16 and its periphery according to the embodiment. Figs. 3 to 5 illustrate the protrusion 16 in a rectangular region indicated by reference symbol III in Fig. 2. Fig. 5 illustrates a cross-section of a portion of the exterior body 10, which is parallel to the XZ plane passing through the line VV in Fig. 1. In Fig. 5, the approximate arrangement range of the energy storage element unit 101 including one or more energy storage elements 100 is indicated by a dotted line. These supplementary matters regarding Fig. 5 also apply to Fig. 6 described later.

[0035] 2 and 3, the exterior body 11 has protrusions 16 arranged in the opening 13. In this embodiment, as shown in FIG. 2, eight protrusions 16 are arranged in the rectangular opening 13 when viewed from the positive direction of the Z axis (hereinafter also referred to as "planar view"). Each of the eight protrusions 16 protrudes in the positive direction of the Z axis. The following description of the protrusions 16 applies commonly to these eight protrusions 16.

[0036] In this embodiment, the protruding portion 16 is integrally provided with the exterior body 11. That is, the protruding portion 16 is formed of a resin such as PC, PP, PE, PS, or PPS. In this embodiment, the protruding portion 16 is connected to the inner circumferential surface 13c of the opening 13 as shown in FIG. 3. Specifically, the protruding portion 16 includes a connection portion 16b that protrudes from the inner circumferential surface 13c in a direction perpendicular to the inner circumferential surface 13c (the positive direction of the X-axis in FIG. 3), and a protruding main body portion 16a that protrudes from the connection portion 16b in the positive direction of the Z-axis. That is, in this embodiment, the protruding portion 16 is directly connected to the inner circumferential surface 13c of the opening 13.

[0037] In FIG. 3, the position of the upper end face (end face in the Z-axis positive direction) of the connection part 16b and the position of the opening end face 13b are aligned in the Z-axis direction, but these positions may not be aligned. For example, in the Z-axis direction, the upper end face of the connection part 16b may be positioned in the Z-axis negative direction from the opening end face 13b. The connection part 16b can also be described as being a part of the side wall part (side wall part 14 in FIG. 3) of the exterior body main body 11. In this case, the connection part 16b is a part of the opening 13 in the exterior body main body 11, and the protruding main body part 16a protruding from the connection part 16b in the Z-axis positive direction is described as being a "protruding part" arranged in the opening 13. The protruding part protruding from the connection part 16b in the Z-axis positive direction is described as being connected to the inner circumferential surface 13c of the opening 13 via the connection part 16b.

[0038] The opening 13 is a portion that forms the opening 13a (see FIG. 2), and is constituted by the upper end portions of the pair of sidewall portions 14 and the pair of sidewall portions 15 as described above. The upper end portion of the sidewall portion 14 is a portion that includes the edge of the sidewall portion 14 in the positive Z-axis direction, and is a portion in the range of 1 / 3 of the length of the sidewall portion 14 in the Z-axis direction. More preferably, the upper end portion of the sidewall portion 14 is a portion in the positive Z-axis direction from the energy storage element 100 in the Z-axis direction. The upper end portion of the sidewall portion 15 is also the same, and is a portion that includes the edge of the sidewall portion 15 in the positive Z-axis direction, and is a portion in the range of 1 / 3 of the length of the sidewall portion 15 in the Z-axis direction. More preferably, the upper end portion of the sidewall portion 15 is a portion in the positive Z-axis direction from the energy storage element 100 in the Z-axis direction. The inner circumferential surface 13c is a portion of the inner surface of each of the sidewall portion 14 and the sidewall portion 15 that is included in the opening 13. That is, the inner circumferential surface 13c is an upper end portion of the inner surface of each of the sidewall portion 14 and the sidewall portion 15.

[0039] The protruding body 16a of the protruding portion 16 protrudes in the Z-axis positive direction from the opening end surface 13b, which is the end surface of the opening 13. When the lid body 50 is fixed to the exterior body 11, the protruding body 16a is inserted into a through hole 52 (see Figs. 2 and 5) formed in the lid body 50. This determines the position of the lid body 50 in the XY plane relative to the exterior body 11, and the tip of the protruding portion 16 protrudes from the through hole 52 in the Z-axis positive direction. The tip protruding from the through hole 52 is heat-crimped, and as a result, as shown in Fig. 5, the welded portion 17 is formed. That is, the tip of the protruding portion 16 is heated and pressurized to melt and spread into a substantially disk shape, and then cooled and solidified to form the welded portion 17. In the process of forming the welded portion 17, the mutually opposing portions of the welded portion 17 and the lid body 50 are welded to each other. That is, the welded portion 17 is a part of the protrusion 16, and is a portion joined to the lid body 50 by welding. In Fig. 5, the portion of the welded portion 17 that is welded to the lid body 50 (welded surface portion 17a) is shown typically by a thick dotted line between the welded portion 17 and the lid body 50. In this manner, the protrusion 16 of the exterior body main body 11 is welded to the lid body 50 while penetrating the lid body 50, and thereby functions as a portion that fixes the lid body 50 to the exterior body main body 11.

[0040] Methods for forming the welded portion 17 include thermal crimping, in which the protrusion 16 is directly heated and pressurized with a metal body or the like, or ultrasonic crimping, in which ultrasonic vibrations are applied to the protrusion 16 using a horn while pressure is applied thereto.

[0041] As described above, the energy storage device 1 according to this embodiment includes the energy storage element 100 and the exterior body 10 that houses the energy storage element 100. The exterior body 10 includes an exterior body main body 11 having an opening 13 that forms an opening 13a in the positive direction of the Z axis, and a lid body 50 that covers the opening 13a. The exterior body main body 11 is disposed in the opening 13 and includes a protruding portion 16 that protrudes in the positive direction of the Z axis. The lid body 50 includes a through hole 52. The protruding portion 16 is inserted into the through hole 52. The protruding portion 16 includes a welded portion 17 that is welded to the lid body 50.

[0042] According to this configuration, when the lid body 50 is placed on the exterior body 11 in the manufacturing (assembly) process of the storage battery 1, the protrusion 16 provided on the exterior body 11 is inserted into the through hole 52 of the lid body 50. Therefore, the lid body 50 can be positioned efficiently or accurately with respect to the exterior body 11. The protrusion 16 is further welded to the lid body 50 at least at the welded portion 17. Therefore, the protrusion 16 can also play a role in fixing the lid body 50 to the exterior body 11, and the protrusion 16 is unlikely to be displaced or change in posture with respect to the exterior body 11. For example, a defect such as "loosening of the bolt" that may occur when the lid body 50 is fixed to the exterior body 11 using a bolt is unlikely to occur. Therefore, the storage battery 1 according to this embodiment is provided with an exterior body 10 with improved reliability.

[0043] In the present embodiment, the protrusion 16 is provided integrally with the exterior body 11. Therefore, there is no need to use a separate member such as a bolt to fix the lid 50 to the exterior body 11. Because the protrusion 16 is made of resin, the weight of the electricity storage device 1 can be reduced compared to the case where, for example, a metal bolt is used.

[0044] 1, 2, and 5, in this embodiment, the welded portion 17 covers the through hole 52 when viewed from the positive direction of the Z axis. Specifically, the welded portion 17 is welded to the peripheral portion of the through hole 52 on the lid outer surface 51a. As a result, the through hole 52 is blocked by the welded portion 17 from the outside (from the positive direction of the Z axis).

[0045] In this way, the welded portion 17 welded to the lid body 50 can cover the through hole 52 formed in the lid body 50 from the outside of the lid body 50. This more reliably seals the through hole 52. That is, the hermeticity against gas or liquid in the through hole 52 is improved. By forming the welded portion 17 to a size that covers the through hole 52 in a plan view, the welded portion 17 can more reliably restrict the movement of the lid body 50 in the positive direction of the Z axis. This more reliably suppresses the movement of the lid body 50 in the positive direction of the Z axis relative to the exterior body main body 11.

[0046] In this embodiment, the lid 50 and the exterior body 11 are further joined to the lid 50 by a joint 18 provided at the opening 13 of the exterior body 11. Specifically, as shown in Figs. 3 to 5, the opening 13 has an opening end surface 13b facing the lid 50. The opening end surface 13b has a joint 18 joined to the lid 50. In Figs. 3 and 4, the joint 18 is typically represented by a patterned area, and in Fig. 5, it is typically represented by a thick dotted line with the reference number "18". In this embodiment, the joint 18 is formed by thermal welding. For example, heat sealing may be used as the thermal welding method. Heat sealing is a method of welding at least two members by heat.

[0047] In this manner, by providing opening end face 13b of exterior body main body 11 with joint portion 18, the joint area between lid body 50 and exterior body main body 11 includes at least the joint area between opening end face 13b and lid body 50 and the joint area between welding portion 17 of protrusion 16 and lid body 50. As a result, lid body 50 and exterior body 10 are joined more firmly.

[0048] In Figs. 3 to 5, the joint 18 is provided over almost the entire width of the opening end surface 13b (X-axis direction in Figs. 3 to 5), but this is not essential. The joint 18 may be provided over at least a part of the width of the opening end surface 13b. Even if the joint 18 is provided over only a part of the width, as long as the joint 18 is disposed over the entire extension direction of the opening end surface 13b (Y-axis direction in Figs. 3 to 5), the sealing property against gas or liquid can be ensured between the opening end surface 13b and the lid body 50. That is, the sealing property can be ensured by the joint 18 surrounding the opening 13a in a plan view. However, from the viewpoint of improving the sealing property and / or improving the fixing force of the lid body 50 to the exterior body main body 11, it is preferable that the joint 18 is provided over almost the entire width of the opening end surface 13b. If the space between the lid 50 and the exterior body 11 does not need to be completely sealed against gas or liquid, the joint 18 may be disposed only partially in the direction in which the open end surface 13b extends.

[0049] It is not essential that opening end surface 13b of exterior body 11 is provided with joint portion 18. Even if opening end surface 13b is not provided with joint portion 18, it is sufficient that welding portion 17 of at least one protrusion 16 is welded to lid body 50. This allows lid body 50 to be fixed to exterior body 11 by the at least one protrusion 16.

[0050] In this embodiment, as shown in FIG. 4, the protruding portion 16 is adjacent to the joint portion 18 when viewed from the positive direction of the Z axis.

[0051] According to this configuration, in a plan view, it is easy to make the joints 18 and the welded parts 17 continuous or to make the joints 18 and the welded parts 17 overlap each other. In the present embodiment, in a plan view, a part of the joints 18 and a part of the welded parts 17 of the protruding parts 16 overlap each other (see FIG. 5, for example). This makes it easier to maintain hermeticity against gas or liquid in the vicinity of the protruding parts 16 of the exterior body 10, for example. In a plan view, the amount of protrusion of the protruding parts 16 into the opening 13a (the amount of protrusion in the positive direction of the X-axis in FIG. 4) is small, so that, for example, when a task of housing a member such as the energy storage element 100 inside the exterior body main body 11 is performed, the protruding parts 16 are unlikely to get in the way of the task.

[0052] 4, in plan view, protruding body portion 16a forming an axis portion (rod-shaped portion) having welding portion 17 and opening end surface 13b are continuous in the X-axis direction. This makes it easier to maintain airtightness in the vicinity of protruding portion 16 of exterior body 10, and allows joint portion 18 to be formed over almost the entire width of opening end surface 13b. This is advantageous for increasing the joint area between lid 50 and exterior body 11.

[0053] It is not essential that the protruding body portion 16a and the joint portion 18 are continuous in a plan view. In other words, the protruding body portion 16a and the joint portion 18 may be separated in a plan view. When the protruding body portion 16a and the joint portion 18 are separated, the protruding body portion 16a and the opening end surface 13b may be separated in a plan view. Regardless of whether the protruding body portion 16a and the joint portion 18 are continuous in a plan view or not, at least a part of the protruding body portion 16a and the opening end surface 13b may overlap in a plan view. An embodiment in which the entire protruding portion overlaps with the opening end surface 13b in a plan view will be described later as Modification Example 2.

[0054] In this embodiment, the exterior body 11 includes a plurality of (specifically, eight) protrusions 16. The plurality of protrusions 16 are arranged along a direction perpendicular to the protruding direction of the protrusions 16 (the Z-axis positive direction). Specifically, the plurality of protrusions 16 are arranged at the upper end portions of the side walls (the Z-axis positive end portions of the side walls 14 and 15) that constitute the opening 13. More specifically, two protrusions 16 are arranged along the Y-axis direction at the upper end portion of the side wall 14, and two protrusions 16 are arranged along the X-axis direction at the upper end portion of the side wall 15.

[0055] According to this configuration, for example, by increasing the number of protrusions 16, it is possible to increase the bonding area between the lid 50 and the exterior body 11. Therefore, the number and layout of the protrusions 16 can be appropriately determined according to the specifications required for the exterior body 10, for example.

[0056] 3 to 5, in this embodiment, the protrusion 16 is connected to the inner circumferential surface 13c of the opening 13. More specifically, the protrusion 16 is directly connected to the inner circumferential surface 13c.

[0057] According to this configuration, the through hole 52 of the lid 50 is provided at a position overlapping with the opening 13a of the exterior body 10 (internal space of the exterior body main body 11) in a plan view. Therefore, the lid 50 is made smaller than when the through hole 52 of the lid 50 is provided outside the opening 13a in a plan view. More specifically, as shown in FIG. 5, the protrusion 16 is disposed in the positive direction of the Z axis of the energy storage element 100. In other words, at least a part of the protrusion 16 overlaps with a part of the energy storage element 100 in a plan view. That is, in this embodiment, as shown in FIG. 5, the space directly below the protrusion 16 (negative direction of the Z axis) is used as a space for disposing a part of the energy storage element 100 (or the energy storage element unit 101). This, for example, reduces the size of the exterior body 10 and / or improves the energy density of the energy storage device 1.

[0058] The above describes the energy storage device 1 according to the embodiment, focusing on the configuration of the protrusion 16 and its periphery. However, the configuration of the protrusion 16 and its periphery in the energy storage device 1 may be different from the configurations shown in Figures 1 to 5. Therefore, below, modified examples of the configuration of the protrusion 16 and its periphery will be described, focusing on the differences from the above embodiment.

[0059] [3-1. Variation 1] 6 is a cross-sectional view showing the configuration of protrusion 16 and its surroundings according to Variation 1 of the embodiment. In energy storage device 1a according to this variation, exterior body 11 has protrusion 16 arranged at opening 13, protruding in the positive direction of the Z axis. Lid 50 has through hole 52. Protrusion 16 has welded portion 17 welded to lid 50 in a state where protrusion 16 penetrates through hole 52. These configurations are common to energy storage device 1 according to the embodiment.

[0060] In this modification, the lid body 50 has a recess 53, which is different from the electricity storage device 1 according to the embodiment. Specifically, the lid body 50 has a recess 53 formed in a recessed shape from the lid outer surface 51a toward the lid inner surface 51b, and the through hole 52 is located inside the recess 53 in a plan view. Furthermore, at least a part of the welding portion 17 in the penetration direction of the through hole 52 (Z-axis direction) is housed in the recess 53. More specifically, the welding surface portion 17a of the welding portion 17 is welded to the bottom surface of the recess 53 (recess bottom surface 53a).

[0061] In this manner, at least a portion of the welded portion 17 is accommodated in the recess 53, thereby reducing the amount of protrusion of the welded portion 17 from the lid outer surface 51a. This allows, for example, more effective use of the space above the lid body 50 (in the positive direction of the Z axis). In FIG. 6, a portion of the welded portion 17 in the Z axis direction protrudes from the lid outer surface 51a, but the entire welded portion 17 in the Z axis direction may be accommodated in the recess 53.

[0062] [3-2. Variation 2] Fig. 7 is an enlarged perspective view of protrusion 26 according to the second modification of the embodiment. Fig. 7 illustrates protrusion 26 in a state before welded portion 27 is formed. Fig. 8 is a cross-sectional view showing protrusion 26 according to the second modification of the embodiment and the configuration of its periphery. The position of the cross section in Fig. 8 corresponds to the position of the cross section in Fig. 5.

[0063] In energy storage device 1b according to this modification, exterior body main body 11 has protrusion 26 arranged at opening 13, protruding in the positive direction of the Z axis. Lid body 50 has through hole 52. Protrusion 26 has welded portion 27 welded to lid body 50 in a state where protrusion 26 passes through through hole 52. Specifically, welded portion 27 has a portion welded to lid body 50 (welded surface portion 27a). These configurations are common to energy storage device 1 according to the embodiment.

[0064] In this modification, protrusion 26 protrudes in the positive direction of the Z axis from opening end face 13b of exterior body main body 11, which differs from the energy storage device 1 according to the embodiment. That is, in a plan view, protrusion 26 entirely overlaps opening end face 13b. By arranging protrusion 26 on opening end face 13b in this manner, when a task of housing components such as energy storage element 100 inside exterior body main body 11 is performed, protrusion 26 is less likely to get in the way of the task.

[0065] More specifically, in this modification, the protrusion 26 and the joint 18 are arranged side by side in the width direction of the opening end surface 13b (X-axis direction in Figs. 7 and 8). Therefore, as in the above embodiment, the joint 18 can be arranged to surround the opening 13a (see Fig. 2) in a plan view. As a result, the joint 18 ensures hermeticity against gas or liquid between the opening end surface 13b and the lid 50. In Fig. 8, the protrusion 26 is arranged in the center of the width direction (X-axis direction) of the opening end surface 13b, but the protrusion 26 may be arranged to one side in the width direction. In other words, the joint 18 may be arranged only on one side of the protrusion 26 in the positive X-axis direction or the negative X-axis direction. Even in this case, the joint 18 can be arranged to surround the opening 13a in a plan view.

[0066] [3-3. Variation 3] Fig. 9 is an enlarged perspective view of protrusion 36 according to Modification 3 of the embodiment. Fig. 9 illustrates protrusion 36 in a state before welded portion 37 is formed. Fig. 10 is a side view showing convex portion 19 and protrusion 36 according to Modification 3 of the embodiment. Fig. 10 illustrates a side view (viewed from the negative Y-axis direction) of a portion of exterior body main body 11 in a state in which exterior body main body 11 is cut along an XZ plane passing through line XX in Fig. 9. Fig. 11 is a perspective view showing protrusion 36 according to Modification 3 of the embodiment and the configuration of its surroundings.

[0067] In an energy storage device 1c according to this modification, exterior body 11 has protrusion 36 arranged at opening 13, protruding in the positive direction of the Z axis. Lid 50 has through hole 52. Protrusion 36 has welded portion 37 welded to lid 50 in a state where protrusion 36 passes through through hole 52. Specifically, welded portion 37 has a portion welded to lid 50 (welded surface portion 37a). Furthermore, protrusion 36 is connected to inner circumferential surface 13c of opening 13. These configurations are common to those of energy storage device 1 according to the embodiment.

[0068] In this modification, the protrusion 36 is connected to the inner circumferential surface 13c via the protruding portion 19, which is different from the energy storage device 1 according to the embodiment. The protruding portion 19 protrudes from the inner circumferential surface 13c toward the inside of the exterior body main body 11 (toward the positive direction of the X-axis in Figs. 9 to 11). Specifically, the protruding portion 19 is provided on the inner surface of the side wall portion 14 of the exterior body main body 11, and is connected to the upper surface (inner bottom surface 12a) of the bottom wall portion 12. More specifically, the protruding portion 19 extends from the upper end of the inner surface of the side wall portion 14 (i.e., the inner circumferential surface 13c of the opening 13) along the inner surface to the inner bottom surface 12a. That is, in this modification, the upper end of the protruding portion 19 is a part of the opening 13. The protruding portion 19 is connected to both the side wall portion 14 and the bottom wall portion 12 of the exterior body main body 11, which can improve the rigidity of the exterior body main body 11, for example. In this modification, the protrusion 36 can be disposed by utilizing the space above the protrusion 19, which contributes to improving the rigidity of the exterior body 11. In other words, the internal space of the exterior body 10 can be effectively utilized.

[0069] 9 to 11, convex end face 19a is located in the negative Z-axis direction relative to opening end face 13b. However, convex end face 19a and opening end face 13b may be in the same position in the Z-axis direction. In FIGS. 9 to 11, protrusion 36 is disposed spaced apart from opening end face 13b, but protrusion 36 may be continuous with opening end face 13b.

[0070] [4. Other Modifications] Although the energy storage device 1 according to the embodiment and its modified examples have been described above, the present invention is not limited to the embodiment and its modified examples. In other words, the embodiment disclosed herein is illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

[0071] The protruding portion 16 may not have a welded portion 17 (see FIG. 1 and FIG. 5) that protrudes in the radial direction of the protruding body portion 16a. For example, the outer peripheral surface of the protruding body portion 16a (see FIG. 3) of the protruding portion 16 may be welded to the inner peripheral surface of the through hole 52 (see FIG. 2 and FIG. 5) of the lid body 50. Even in this case, it is possible to close the gap between the outer peripheral surface of the protruding body portion 16a and the inner peripheral surface of the through hole 52 with a resin (a part of at least one of the protruding portion 16 and the lid body 50) that has cooled and solidified after melting. In other words, the protruding body portion 16a may not protrude from the through hole 52. FIG. 12 is a cross-sectional view showing an example of the protruding portion 16 that does not protrude from the through hole 52 of the lid body 50. In FIG. 12, the welded portion 17 is formed by a resin that closes the gap between the outer peripheral surface of the protruding body portion 16a and the inner peripheral surface of the through hole 52. As shown in Fig. 12, the end of the protruding main body portion 16a may be located lower than the lid outer surface 51a, or may be located at the same position as the lid outer surface 51a. This makes it easier to prevent the welded portion 17 from protruding outward from the lid outer surface 51a, and also makes it easier to reduce the amount of protrusion of the welded portion 17 protruding outward from the lid outer surface 51a. The welded portion 17 in Fig. 12 may be formed by ultrasonic welding or the like.

[0072] The protrusion 16 does not have to be integral with the exterior body 11. For example, a protrusion manufactured as a separate part from the exterior body 11 may be fixed to the exterior body 11. As a method of fixing, various methods such as welding, adhesion, fitting, or fastening using a bolt may be adopted. When the protrusion is a separate part from the exterior body 11, the protrusion may be fixed to the opening 13 of the exterior body 11 after a member such as the energy storage element 100 is accommodated inside the exterior body 11. This makes it easier to accommodate a member such as the energy storage element 100 inside the exterior body 11.

[0073] A method other than heat sealing may be used to join the opening end surface 13b and the lid body 50. Examples of methods other than heat sealing include ultrasonic welding and laser welding. In ultrasonic welding, for example, the opening end surface 13b is melted by frictional heat caused by ultrasonic vibration and then cooled and solidified, thereby forming the joint portion 18 to be joined to the lid body 50. In laser welding, for example, the opening end surface 13b is melted by irradiation with laser light and then cooled and solidified, thereby forming the joint portion 18 to be joined to the lid body 50. Adhesive bonding may be used as a method to join the opening end surface 13b and the lid body 50. A chemical method using a solvent may be used as a method to join the opening end surface 13b and the lid body 50. For example, the opening end surface 13b may be melted using a solvent such as dichloromethane and then solidified, thereby forming the joint portion 18 to be joined to the lid body 50 on a part or all of the opening end surface 13b.

[0074] The opening end surface 13b and the lid body 50 may be joined using a bolt made of metal or resin. In this case, a gasket may be disposed between the opening end surface 13b and the lid body 50 to ensure airtightness against gas or liquid between the opening end surface 13b and the lid body 50. When the opening end surface 13b and the lid body 50 are joined using a bolt, the portion of the opening end surface 13b that contacts the lid body 50 or the gasket is described as the joint portion 18 of the opening end surface 13b. When a gasket is disposed between the opening end surface 13b and the lid body 50, the protrusion 16 can restrict the movement of the gasket in a direction approaching the inside of the opening 13a. Therefore, the protrusion 16 can suppress the gasket from falling into the inside of the opening 13a.

[0075] When a gasket is disposed between the opening end surface 13b and the lid body 50, the welding portion 17 of the protrusion 16, instead of a bolt, may function as a portion that maintains the gasket in a compressed state between the opening end surface 13b and the lid body 50. For example, in a state in which a gasket is disposed between the opening end surface 13b and the lid body 50, the lid body 50 is pressed toward the opening end surface 13b using a jig or the like. In this state, the tip of the protrusion 16 is melted, and the melted tip is cooled and solidified. That is, the welding portion 17 is formed by heat caulking the tip of the protrusion 16. In this case, the welding portion 17 can limit the movement of the lid body 50 in the Z-axis plus direction relative to the exterior body main body 11, so that the gasket can be maintained in a compressed state between the opening end surface 13b and the lid body 50. In order to obtain this effect uniformly in the extension direction of the opening end surface 13b (X-axis direction and Y-axis direction), it is preferable that a plurality of protrusions 16 are arranged along the extension direction.

[0076] The portion of the protrusion 16 that is inserted into the through hole 52 does not have to be cylindrical as shown in Fig. 3. The portion that is inserted into the through hole 52 may be, for example, a polygonal prism shape such as a square prism. The outer shape of the cross section of the portion that is inserted into the through hole 52 (a cross section perpendicular to the protruding direction of the protrusion 16) may be a shape formed by straight lines and curves.

[0077] The shape of the exterior body 10 does not have to be a rectangular parallelepiped shape as shown in Figures 1 and 2. For example, an exterior body having another shape, such as a cylindrical shape, may be used as the exterior body that houses the energy storage element unit 101.

[0078] At least a part of each of the welded parts 27 and 37 according to the second and third modifications of the embodiment shown in Figures 7 to 11 may be accommodated in a recess 53 (see Figure 6) provided in the lid 50. Additionally, configurations constructed by arbitrarily combining the components included in the above-described embodiment and its modifications are also included within the scope of the present invention. [Industrial Applicability]

[0079] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0080] 1, 1a, 1b, 1c power storage device 10 Exterior body 11 Exterior body 13 Opening 13a aperture 13b Opening end surface 13c Inner surface 16, 26, 36 protrusion 17, 27, 37 Welded area 18 Joint 50 Lid 52 Through hole 100 Energy storage element 101 Energy storage element unit

Claims

1. A storage element; An exterior body that houses the energy storage element, The exterior body is An exterior body having an opening that forms an opening in a first direction; A cover that closes the opening, The exterior body includes a protrusion disposed in the opening and protruding in the first direction, The lid body has a through hole, The protrusion is inserted into the through hole and includes a welding portion welded to the lid. Energy storage device.

2. The welded portion covers the through hole when viewed from the first direction. The power storage device according to claim 1.

3. the opening has an opening end surface facing the lid, The opening end surface has a joint portion that is joined to the lid body. The electricity storage device according to claim 1 or 2.

4. The protruding portion is adjacent to the joint portion when viewed from the first direction. The electricity storage device according to claim 3.

5. The plurality of protrusions are arranged along a second direction perpendicular to the first direction. The electricity storage device according to claim 1 or 2.

6. The protrusion is connected to an inner circumferential surface of the opening. The electricity storage device according to claim 1 or 2.

Images