Metal member, electrode terminal provided with same, and power storage module

Abstract

The present disclosure relates to a metal member, an electrode terminal provided with the metal member, and an electricity storage module. Provided is a technique for reducing the risk of scattering of molten metal when welding a metal member, which is provided with a first metal member and a second metal member that overlap each other, and another metal member. A metal member disclosed herein includes a first member made of metal and a second member made of metal. The second member has a space between the first member and the second member in which gas can be retained. The second member has a vent hole that communicates the space with outside air.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a metal member, an electrode terminal provided with the metal member, and a power storage module. BACKGROUND

[0002] In recent years, secondary batteries such as lithium-ion secondary batteries and power storage modules including the same have been increasingly widespread. Such secondary batteries and power storage modules are suitable for use in, for example, vehicle drive power sources such as electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like.

[0003] Japanese Patent Application Publication No. 2001-87879 discloses a laser welding method in which laser light is irradiated to a plurality of materials to be welded that are overlapped with each other and the materials to be welded are fused to be joined to each other. The method is characterized in that a hole having a smaller diameter than a joining predetermined diameter is formed in advance in a material to be welded that is different from a material to be welded that is irradiated with laser light first, laser light having a larger diameter than the diameter of the hole is irradiated to a position of the material to be welded that is not formed with the hole and corresponds to the hole, and the materials to be welded are fused to be joined to each other. It is described in the publication that the hole is a vent hole. Thus, when there is an impurity between the materials to be welded, the impurity is evaporated due to the heat of fusion and the evaporated gas generated thereby escapes from the hole. Thus, a good welding state is achieved, and thus a sufficient joining strength can be obtained.

[0004] Japanese Patent Application Publication No. 2019-166533 discloses a configuration of laser lap welding in which a first member configured to face an irradiation side of laser light and a second member overlapped with a side of the first member opposite to the irradiation side are joined by irradiating laser light. The first member has at least one through-hole provided through in a direction in which the second member is overlapped. The first member and the second member are joined by a welding portion that includes, from a region in which the first member and the second member are overlapped, a portion of a boundary between the overlapped region and a through region to the through region projected to the second member. It is described in the publication that, by this configuration, the joining strength of the overlapped members can be improved.

[0005] A manufacturing method of a joined structure in which a first member composed of an iron-based material subjected to plating treatment and a second member different in material from the first member are joined is disclosed in Japanese Patent Application Publication No. 2020-19061. The manufacturing method includes a step of forming a through-hole in the second member; a step of superimposing the first member and the second member with the through-hole facing the first member; a step of inserting an iron-based insert member into the through-hole of the second member until the insert member abuts against the first member, the insert member including an insertion portion and a non-insertion portion, and provided with a through-hole that communicates from the insertion portion to the non-insertion portion; and a step of forming a weld metal portion at an abutment portion of the first member and the insert member to join the first member and the insert member. In the publication, it is described that, with this structure, the first member composed of the iron-based material subjected to the plating treatment and the second member different in material from the first member can be joined in a sound state without a pore defect without a gap being provided between the two members.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2001-87879

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-166533

[0010] Patent Document 3: Japanese Patent Application Publication No. 2020-19061

[0011] When welding another member made of metal to a metal member provided with a first member made of metal and a second member made of metal that overlap each other, in a case where there is a space between the first member and the second member in which gas can be trapped, for example, the gas in the space can expand due to heat imparted. Due to the gas, molten metal sometimes scatters to the surroundings. The scattering of the molten metal can degrade the quality of the welding of the metal member and the other member, and thus is not preferable. SUMMARY

[0012] Problems to be Solved by the Invention

[0013] Therefore, the present application was completed in view of the above circumstances, and aims to provide a technique that reduces the risk of scattering of molten metal when welding a metal member provided with a first member made of metal and a second member made of metal that overlap each other and another metal member.

[0014] Means for Solving the Problems

[0015] According to the technology disclosed herein, a metal member is provided. The metal member includes a first member made of metal and a second member made of metal. The second member has a space in which gas can be trapped between the first member. The second member has a vent hole that communicates the space with outside air. According to this structure, when welding the metal member having the first member made of metal and the second member made of metal that overlap each other and another metal member, the risk of scattering of molten metal can be reduced.

[0016] According to the technology disclosed herein, an electrode terminal for an electrical storage device is provided. The electrode terminal includes the metal member described above. According to this structure, when welding the metal member described above and another metal member, the risk of scattering of molten metal can be reduced. Thus, the welding quality of the electrode terminal and another member can be improved.

[0017] According to the technology disclosed herein, an electrical storage module having an electrode terminal and a bus bar is provided. The electrical storage module includes the metal member described above. The electrode terminal includes a first member and a second member. The bus bar includes a third member. According to this structure, when welding the electrode terminal and the bus bar, the risk of scattering of molten metal can be reduced. Thus, the electrical storage module in which the welding quality of the electrode terminal and the bus bar is improved can be constructed. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a perspective view of an electrical storage module 100.

[0019] Figure 2 is a II-II sectional view of Figure 1

[0020] Figure 3 is a view as seen from the upper surface 141 side of the bus bar 14.

[0021] REFERENCE NUMERALS

[0022] 100 electrical storage module

[0023] 12 electrical storage device

[0024] 14 bus bar

[0025] 14h through hole

[0026] 30 case

[0027] 40 positive electrode terminal

[0028] 50 negative electrode terminal

[0029] 54 negative electrode external terminal

[0030] 56 first member

[0031] 58 second member​

[0032] 581 First Page

[0033] 582 concavity

[0034] 58h vent

[0035] 58S Space

[0036] 60 Insulating components Detailed Implementation

[0037] The following describes one embodiment of the energy storage device disclosed herein. The embodiment described herein is not specifically limited to the technology disclosed herein. Unless otherwise specifically mentioned, the technology disclosed herein is not limited to the embodiment described herein. The accompanying drawings are schematic and do not necessarily reflect the actual object. Components and parts that perform the same function are appropriately labeled with the same reference numerals, and sometimes repeated descriptions are omitted. In the accompanying drawings, the reference numerals “R,” “L,” “U,” “D,” “F,” and “Rr” respectively represent “right,” “left,” “up,” “down,” “front,” and “rear.” Unless otherwise specifically mentioned, the expression “A~B” indicates “above A and below B,” and also includes the meaning of “above A and below B.”

[0038] In this specification, "energy storage device" refers to a device that generates charge and discharge by the movement of charge carriers between a pair of electrodes (positive and negative electrodes) via an electrolyte. Energy storage devices include secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, as well as capacitors such as lithium-ion capacitors and double-layer capacitors. For example, an energy storage device can be a lithium-ion secondary battery.

[0039] Figure 1 This is a 3D view of the energy storage module 100. (See diagram below.) Figure 1 As shown, the energy storage module 100 includes multiple energy storage devices 12 and a busbar 14. For example... Figure 1 As shown, the energy storage devices 12 are arranged with their first surfaces 30a facing each other. Here, the multiple energy storage devices 12 are arranged in a direction from one first surface 30a of each energy storage device 12 towards the first surface 30a of the other. The direction in which the multiple energy storage devices 12 are arranged is... Figure 1 The direction from the rear (Rr) side to the front (F) side. Hereinafter, the direction in which the multiple energy storage devices 12 are arranged will also be referred to as the "arrangement direction P".

[0040] exist Figure 1 In the illustrated configuration, the energy storage device 12 has a cuboid-shaped housing 30, with a pair of opposing first surfaces 30a, a pair of opposing second surfaces 30b, and a bottom surface 30c. Here, the first surface 30a is rectangular and is the surface with the largest area in the housing 30. Figure 1As shown, the pair of opposing first surfaces 30a are surfaces extending from the pair of opposing long sides of the bottom surface 30c. Here, the second surface 30b is a rectangle, and is the surface sandwiched between the pair of opposing first surfaces 30a. Figure 1 As shown, the pair of opposing second faces 30b are faces that extend from the pair of opposing short sides of the bottom face 30c.

[0041] The energy storage device 12, for example, includes a housing 30, electrodes (not shown) housed within the housing 30, and an electrolyte (not shown). Figure 1 As shown, the housing 30 includes a main body 31 and a sealing plate 32. The main body 31 is, for example, a component that houses the electrode body and the electrolyte. Here, the main body 31 has a cuboid shape with one side being an opening. Figure 1 In the arrangement shown, the main body 31 has a pair of opposing first surfaces 30a, a pair of opposing second surfaces 30b, and a bottom surface 30c. Here, the bottom surface 30c faces the opening. The sealing plate 32 is, for example, a member that closes the opening of the main body 31. The sealing plate 32 has a shape corresponding to the opening of the main body 31, here rectangular (including approximately rectangular, the same below). The sealing plate 32 has a first through hole (not shown) and a second through hole 322 (see reference). Figure 2 Here, the first through hole is a through hole through which the positive terminal 40 is inserted. Here, the second through hole 322 is a through hole through which the negative terminal 50 is inserted. It should be noted that the electrode body and electrolyte of the energy storage device 12 can be any type of energy storage device (such as a lithium-ion secondary battery) without any particular restrictions.

[0042] In this embodiment, the energy storage device 12 has a positive terminal 40 and a negative terminal 50 in the housing 30. Figure 1 and Figure 2 In the configuration shown, the positive terminal 40 and the negative terminal 50 are mounted on the sealing plate 32. The negative terminal 50 will be explained first below.

[0043] Figure 2 yes Figure 1 Sectional view II-II. Figure 2 The image shows a magnified cross-section near the connection between the busbar 14 and the negative terminal 50. (See image for enlarged view.) Figure 2As shown, the negative terminal 50 has a negative current collector terminal 52 and a negative external terminal 54. The negative current collector terminal 52 is, for example, a component connected to the negative electrode of an electrode body (not shown). In this embodiment, the negative current collector terminal 52 is flat. The negative current collector terminal 52 is arranged along the inner surface 32d of the sealing plate 32. The negative current collector terminal 52 is connected to the negative electrode of the electrode body, for example, via a current collector plate (not shown). The negative current collector terminal 52 has a through hole 52h. In this embodiment, the negative current collector terminal 52 is connected to the negative external terminal 54 by inserting a portion of the negative external terminal 54 into the through hole 52h. The negative current collector terminal 52 can be, for example, copper or a copper alloy (meaning an alloy containing at least 70% by mass of copper in its entire composition, hereinafter the same).

[0044] The negative external terminal 54 is, for example, a portion connected to the busbar 14. In this embodiment, the negative external terminal 54 has a portion disposed inside the housing 30 and a portion disposed outside the housing 30. Figure 2 As shown, the negative external terminal 54 includes a first member 56 and a second member 58. The first member 56 is, for example, a portion connected to the negative current collector terminal 52. In this embodiment, the first member 56 includes a connecting portion 56a and a shaft portion 56b. The connecting portion 56a is, for example, a portion connected to the second member 58. In this embodiment, the connecting portion 56a is circular. Here, the connecting portion 56a is housed inside the recess 582 of the second member 58. The shaft portion 56b is, for example, a portion connected to the negative current collector terminal 52. In this embodiment, the shaft portion 56b is cylindrical. The shaft portion 56b extends from the connecting portion 56a. The shaft portion 56b is inserted through the through hole 52h of the negative current collector terminal 52.

[0045] The first component 56 is, for example, made of a first metal. The first metal may be, for example, aluminum, an aluminum alloy (meaning an alloy containing at least 70% by mass of aluminum in its total composition, hereinafter the same), copper, or a copper alloy. Although not particularly limited, the first metal and the second metal described later may be the same or different from each other. In the case where the first metal and the second metal are different metals, the first metal is preferably copper or a copper alloy.

[0046] The second component 58 is, for example, the location where the welded busbar 14 is located. In this embodiment, the second component 58 is flat. The second component 58 is arranged along the outer surface 32u of the sealing plate 32. Figure 2As shown, the second member 58 has a non-through recess 582 on its first surface 581 in the thickness direction. A connecting portion 56a of the first member 56 is housed in the recess 582, and its peripheral portion is riveted to the inner wall surface of the recess 582. Here, "the peripheral portion of the connecting portion 56a of the first member 56 is riveted to the inner wall surface of the recess 582" means, for example, that the first member 56 is fixed relative to the second member 58 by pressing the peripheral portion of the connecting portion 56a of the first member 56 against the inner wall surface of the insertion hole 582. Here, the second surface 584 in the thickness direction of the second member 58 is a flat surface. In this embodiment, a busbar 14 is welded to the second surface 584.

[0047] In this embodiment, the second component 58 has a space 58S between it and the first component 56. Here, space 58S is a space where gas can be retained. Figure 2 In the manner shown, a space 58S is created between the inner wall of the recess 58 and the connecting portion 56a of the first member 56 housed within the recess 58. For example, when the upper end face of the connecting portion 56a is recessed, a space 58S may be created between the connecting portion 56a and the inner wall surface of the recess 58.

[0048] like Figure 2 As shown, the second component 58 has a vent 58h. The vent 58h is, for example, a through hole that connects the space 58S to the outside air. Here, the vent 58h is provided at a location that can communicate with the through hole 14h of the manifold 14 described later. The size, planar shape, etc. of the vent 58h are not particularly limited as long as the effect of the technology disclosed herein can be achieved, and can be appropriately set.

[0049] The second component 58 is, for example, made of a second metal. The second metal may be, for example, aluminum, an aluminum alloy, copper, or a copper-based alloy. When the first metal and the second metal are different metals, the second metal is preferably aluminum or an aluminum alloy.

[0050] The positive terminal 40 may, for example, have the same construction as the negative terminal 50. Therefore, descriptions related to the construction of the positive terminal 40 are omitted here. The positive terminal 40 is preferably, for example, made entirely of aluminum or an aluminum alloy.

[0051] like Figure 2As shown, the energy storage device 12 includes an insulating member 60. The insulating member 60 is, for example, a member that insulates the negative external terminal 54 from the sealing plate 32, and the sealing plate 32 from the negative current collector terminal 52. In this embodiment, the insulating member 60 is disposed between the negative external terminal 54 and the outer surface 32u of the sealing plate 32, between the negative external terminal 54 and the second through hole 322, and between the inner surface 32d of the sealing plate 32 and the negative current collector terminal 52. As the material constituting the insulating member 60, materials used for insulating members in such energy storage devices (e.g., lithium-ion secondary batteries) can be used without particular limitation. Furthermore, the insulating member 60 can be integrally formed to achieve the above-described functions, or it can be formed by combining multiple components. Although not shown in the figure, the energy storage device 12 also includes the same insulating member on the positive side.

[0052] Busbar 14 is, for example, a component that electrically connects two adjacent energy storage devices 12. In this embodiment, busbar 14 is flat. Figure 1 As shown, the manifold 14 has a through hole 14h. The size, planar shape, etc., of the vent hole 58h are not particularly limited, and can be appropriately set as long as the effect of the technology disclosed herein is achieved. The manifold 14 is, for example, made of aluminum or an aluminum alloy.

[0053] like Figure 3 As shown, the busbar 14 is mounted on two adjacent energy storage devices 12 in the arrangement direction P. In this embodiment, the busbar 14 is mounted on the positive terminal 40 of one of the two adjacent energy storage devices 12 in the arrangement direction P and the negative terminal 50 of the other energy storage device 12.

[0054] Figure 2 This is a view taken from the upper surface 141 side of the busbar 14. (See diagram below.) Figure 3 and Figure 2 As shown, the busbar 14 is mounted on the negative external terminal 54. Figure 3 and Figure 2 In the illustrated configuration, the manifold 14 is mounted on the second surface 584 of the second member 58. In this embodiment, the through hole 14h of the manifold 14 overlaps with the vent hole 58h of the second member 58. Thus, the space 58S communicates with the outside air.

[0055] In this embodiment, the busbar 14 is welded to the positive terminal 40 of one of two adjacent energy storage devices 12 in the arrangement direction P and the negative terminal 50 of the other energy storage device 12. Figure 3 and Figure 3In the manner shown, the busbar 14 is welded to the negative electrode external terminal 54 (welding part 14a). The busbar 14 is also welded to the second member 58. The method for welding the electrode terminal and the busbar 14 can be, for example, laser welding or resistance welding. From the viewpoint of improving welding strength, laser welding is preferred.

[0056] like Figure 3 As shown, the second component 58 and the manifold 14 are welded around the vent 58h. Figure 1 In the illustrated configuration, when the first surface 30a is viewed from the front, welded portions 14a are provided on the left (L) and right (R) sides of the vent 58h. Furthermore, the welded portions 14a can be positioned simply around the vent 58h. In other embodiments, the welded portions 14a may also be provided on the upper (U) and lower (D) sides of the vent 58h. Alternatively, the welded portions 14a may be arranged in a ring shape surrounding the vent 58h.

[0057] like ​ As shown, in the energy storage module 100, a plurality of energy storage devices 12 are constrained in the arrangement direction P. The energy storage module 100 includes spacers 11 and a pair of end plates 17. The spacers 11 are disposed between adjacent energy storage devices 12 in the arrangement direction P. The end plates 17 are respectively disposed at both ends of the plurality of energy storage devices 12 arranged in the arrangement direction P, constraining the plurality of energy storage devices 12. The end plates 17 are bridged by metal constraint bands 18. The ends of the constraint bands 18 are fixed by screws 19.

[0058] As described above, the metal component (here, the negative terminal 50) comprises a first metal component 56 and a second metal component 58. The second component 58 overlaps with the first component 56. The second component 58 has a space 58S between itself and the first component 56, where gas can be trapped. The second component 58 has a vent 58h that connects the space 58S to the outside air.

[0059] In other words, within the metal component (here, the negative end 50), a space 58S exists between the overlapping first component 56 and the second component 58. Here, the second component 58 has a vent 58h, allowing the space 58S to communicate with the outside air. Therefore, for example, when welding other metal components to the metal component, the gas (e.g., air) within the space 58S, which expands due to the applied heat, is discharged into the outside air through the vent 58h. This reduces the internal pressure of the space 58S, thereby reducing the risk of molten metal (e.g., molten second component 58) scattering into the surroundings.

[0060] The second member 58 may also have a non-through recess 582 on the first surface 581. A portion of the first member 56 (here, the connecting portion 56a) may be housed inside the recess 582. A space 58S is created between the inner wall of the recess 582 and the portion of the first member 56 housed within the recess 582. In the space 58S formed by the inner wall of the recess 582 and the portion of the first member 56 housed therein (here, the connecting portion 56a), the internal pressure caused by gas expansion easily increases. Therefore, by providing a vent 58h that connects such a space 58S to the outside air, the effects of the technology disclosed herein can be better achieved.

[0061] The metal constituting the first component 56 and the metal constituting the second component 58 can also be different from each other. Therefore, the first component 56, which serves as a connecting member connected to the negative current collector terminal 52 that collects current from the negative electrode body, and the second component 58, which serves as a connecting member connected to the busbar 14, can be made of different metals. Thus, the conductivity between the electrode body, the negative terminal 50, and the busbar 14 can be improved.

[0062] The metal component (here, the negative terminal 50) may also include a third metal component (here, the busbar 14). The third component may also be placed on the surface of the second component 58 and welded to it. As described above, since a vent 58h is provided in the second component 58, the internal pressure of the space 58S can be reduced. Therefore, when the third component is welded to the second component 58, the risk of molten metal (e.g., molten second component 58) scattering to the surroundings can also be reduced.

[0063] The second component 58 and the third component (here, the manifold 14) can also be welded around the vent 58h. This imparts heat to the area around the vent 58h, which becomes the outlet for gas from space 58S, during welding. Therefore, gas can be discharged from space 58S more efficiently.

[0064] The third component (here, manifold 14) may also have a through hole 14h. The vent 58h of the second component 58 may also be connected to the through hole 14h of the third component. By connecting the through hole 14h with the vent 58h, gas can be discharged from the space 58S more efficiently.

[0065] As described above, the energy storage device 12 includes a negative terminal 50. By including the negative terminal 50, when the busbar 14 is soldered to the negative terminal 50, gas can be efficiently discharged from the space 58S to the outside air. Therefore, when the busbar 14 is soldered to the energy storage device 12, the risk of molten metal (e.g., molten second component 58) scattering to the surroundings can be reduced. Thus, an energy storage module 100 with improved soldering quality between the electrode terminals and the busbar 14 can be constructed.

[0066] The energy storage module 100 includes a negative terminal 50 comprising a first component 56 and a second component 58 as an electrode terminal. The busbar 14 includes a third component welded to the metal component comprising the first component 56 and the second component 58. Therefore, when the busbar 14 is welded to the energy storage device 12, the risk of molten metal (e.g., molten second component 58) scattering to the surroundings can be reduced. This improves the welding quality between the electrode terminals and the busbar 14 in the energy storage module 100.

[0067] The technology disclosed herein may include the technology described in the following items.

[0068] Item 1:

[0069] A metal component comprising a first metal component and a second metal component overlapping the first metal component, wherein...

[0070] The second component has a space between itself and the first component where gas can be trapped, and has a vent that allows the space to communicate with the outside air.

[0071] Item 2:

[0072] According to the metal component described in item 1, wherein,

[0073] The second component has a non-through recess on its first surface.

[0074] A portion of the first component is housed inside the recess.

[0075] The space is created between the inner wall of the recess and a portion of the first member housed within the recess.

[0076] Item 3:

[0077] The metal component according to item 1 or 2, wherein,

[0078] The metals constituting the first component and the metals constituting the second component are different from each other.

[0079] Item 4:

[0080] The metal component according to any one of items 1 to 3, wherein,

[0081] The metal component also includes a third metal component.

[0082] The third component is placed on the surface of the second component and welded to the second component.

[0083] Item 5:

[0084] According to the metal component described in item 4, wherein...

[0085] The second component and the third component are welded around the vent.

[0086] Item 6:

[0087] According to item 4 or 5, the metal component wherein...

[0088] The third component has a through hole.

[0089] The vent of the second component is connected to the through hole of the third component.

[0090] Item 7:

[0091] An electrode terminal, the electrode terminal being used in an energy storage device, wherein,

[0092] The electrode terminal comprises any one of items 1 to 3.

[0093] Item 8:

[0094] An energy storage module, the energy storage module having electrode terminals and a bus bar, wherein,

[0095] The energy storage module includes the metal component described in any one of items 4 to 6.

[0096] The electrode terminal includes the first component and the second component.

[0097] The busbar includes the third component.

[0098] The embodiments of the technology disclosed herein have been described above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations to the specific examples illustrated above.

Claims

1. A metal component comprising a first metal component and a second metal component overlapping the first metal component, wherein, The second component has a space between itself and the first component where gas can be trapped, and has a vent that allows the space to communicate with the outside air.

2. The metal component according to claim 1, wherein, The second component has a non-through recess on its first surface. A portion of the first component is housed inside the recess. The space is created between the inner wall of the recess and a portion of the first member housed within the recess.

3. The metal component according to claim 1, wherein, The metals constituting the first component and the metals constituting the second component are different from each other.

4. The metal component according to claim 1, wherein, The metal component also includes a third metal component. The third component is placed on the surface of the second component and welded to the second component.

5. The metal component according to claim 4, wherein, The second component and the third component are welded around the vent.

6. The metal component according to claim 4, wherein, The third component has a through hole. The vent of the second component is connected to the through hole of the third component.

7. An electrode terminal, said electrode terminal being used in an energy storage device, wherein, The electrode terminal comprises a metal component as described in any one of claims 1 to 3.

8. An energy storage module, the energy storage module comprising electrode terminals and a busbar, wherein, The energy storage module comprises the metal component as described in any one of claims 4 to 6. The electrode terminal includes the first component and the second component. The busbar includes the third component.

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