JP2016048634A - Power storage device, and manufacturing method of power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device which reduces a welding defect in a welding part between a termination member that holds a power storage element, and a frame., and a manufacturing method of the power storage device.SOLUTION: The power storage device includes at least one power storage element 1 and a holding member 3 for holding the power storage element 1. The holding member 3 includes: a termination member 30 that is disposed along the power storage element 1 in a first direction; and a frame 31 that is disposed along the power storage element in a second direction. The holding member 3 includes: a welding part 32 where fixing part of the termination member 31 and a fixing part of the frame 31 are welded along an edge of a predetermined area in the state where the fixing parts are overlapped; and a communication part for communicating the fixing part of the termination member 30, the fixing part of the frame 31, an enclosure area surrounded by the welding part 32 and the outside of the enclosure area.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device including a power storage element and a method for manufacturing the power storage device.

  Since an electric vehicle requires a large-capacity power source, an assembled battery structure including a plurality of batteries is used. As shown in FIG. 15, this type of assembled battery structure includes a battery 91, a pair of sandwiching members 92 and 92 disposed at both ends of the battery 91, and a fastening member 93 that connects the sandwiching members 92 and 92 to each other. . The clamping member 92 and the fastening member 93 are fastened (joined) by a nut 94, a screw, or the like.

  In recent years, due to the demand for weight reduction, in the assembled battery structure 90, the fixing portion between the clamping member 92 and the fastening member 93 may be joined by welding without using a nut 94 or a screw (see Patent Document 1). In this welding, in order to increase the welding area and secure the bonding strength of the fixed portion, the welded portion 95 is in an annular shape surrounding the predetermined region 96 in a state where the fixed portions are overlapped with each other as shown in FIG. May be welded.

  However, in this case, a small hole is formed in the welded portion 95 (that is, a welding defect is generated), and the strength of the welded portion may be lowered.

  Specifically, the parts to be joined between the clamping member 92 and the fastening member 93 are overlapped and welded in an annular shape so as to surround the predetermined region 96 at the overlapped part. That is, the welded portion 95 is formed in a closed ring shape at the fixing portion between the clamping member 92 and the fastening member 93. At this time, in the region surrounded by the welded portion 95 and the portion (fixed portion) where the clamping member 92 and the fastening member 93 are overlapped, air expands due to heat during welding and immediately after welding (before cooling and solidifying). ) May be blown out through the welded portion 95. In this case, a hole remains in the hardened welded portion 95 (that is, a welding defect occurs), and as a result, the strength (weld strength) of the welded portion 95 between the clamping member 92 and the fastening member 93 that holds the battery decreases.

JP 2010-92610 A

  Therefore, an object of the present invention is to provide a power storage device with few welding defects in a welded portion between a terminal member holding a power storage element and a frame, and a method for manufacturing the power storage device.

The power storage device according to the present invention includes:
At least one power storage element;
A holding member for holding the electricity storage element,
The holding member has a termination member disposed along the power storage element in the first direction, and a frame disposed along the power storage element in the second direction intersecting the first direction,
The termination member has a fixing portion joined to the frame,
The frame has a fixing portion joined to the termination member,
The holding member
In a state where the fixed portion of the end member and the fixed portion of the frame are overlapped, a welded portion in which the fixed portions are welded along the peripheral edge of the predetermined region;
It has a fixed part of the end member, a fixed part of the frame, and an enclosed area surrounded by the welded part and a communicating part that communicates the outside of the enclosed area.

  According to such a configuration, when the power storage device is manufactured, when the terminal member fixing portion and the frame fixing portion are welded, the surrounding region surrounded by the welding portion, the terminal member fixing portion, and the frame fixing portion. In this case, even if a gas such as air expands, the gas flows out from the communicating portion. For this reason, at the time of manufacturing, it is possible to prevent gas from being ejected from the welded part immediately after welding, thereby preventing the occurrence of holes or the like due to the gas jetting in the welded part, that is, welding defects in the welded part. Can be prevented. For this reason, a high-quality power storage device can be obtained.

  Further, when the member to be welded has a metal layer having a boiling point lower than the melting point of the base material in the member, the metal constituting the metal layer is evaporated (vaporized) by heat when welding the member. That is, gas is generated. In the above power storage device, since the communication portion is provided, even if the metal constituting the metal layer evaporates (vaporizes) due to heat generated when welding the termination member and the frame at the time of manufacture, the gas metal ( Generated gas) flows out from the enclosed area to the outside through the communication portion.

  For this reason, at least one fixing part of the fixing part of the termination member and the fixing part of the frame has a metal layer having a boiling point lower than the melting point of the base material of either the fixing part of the termination member or the fixing part of the frame. Even if it has, the ejection of the gas (welding defect) in a welding part is prevented reliably. Thereby, a high-quality power storage device can be obtained.

  The communication portion is a through hole provided in at least one of the fixing portion of the termination member and the fixing portion of the frame, and is configured by a through hole that communicates the surrounding region and the outside of the surrounding region. May be.

  With a simple configuration such as a through-hole, a configuration for allowing gas to flow out from the surrounding region is realized, whereby a power storage device with few welding defects can be obtained.

Also,
The welded portion is a shape in which a part of the peripheral shape of the predetermined region is opened,
The communication part may be constituted by the opened part in the welded part.

  As described above, by opening a part of the peripheral shape of the predetermined region, a configuration in which gas flows out from the surrounding region is realized, and a power storage device with few welding defects can be obtained.

in this case,
The peripheral shape of the predetermined region is an oval shape having a pair of opposing arc portions and a pair of straight portions connecting the ends of the arc portions,
It is preferable that the communication part is provided in the linear part.

  According to such a configuration, when a force in a direction away from the overlapped terminal member fixing portion and the frame fixing portion is applied, both ends of the welded portion face each other in a straight line, so that stress is welded. Concentration at each end of the portion is effectively prevented.

  The power storage element expands and contracts with charge and discharge. When the power storage element expands, at least one of the termination member and the frame disposed along the power storage element is pushed by the power storage element, and thereby a force is applied to the welded portion between the termination member and the frame. When this force is applied to the welded portion in the shearing direction, the welded portion is easily broken as compared with a case where a force is applied to the welded portion in the compressing direction.

  For this reason, in the power storage device, when the fixing portion of the terminal member is disposed between the fixing portion of the frame and the power storage element, when the power storage element expands, the force applied to the welded portion due to the expansion is increased. The welded portion can be compressed, and as a result, the strength of the welded portion can be sufficiently ensured.

In addition, a method for manufacturing a power storage device according to the present invention includes:
The fixing portion of the termination member arranged along the electricity storage element in the first direction and the fixing portion of the frame arranged along the electricity storage element in the second direction intersecting the first direction are overlapped,
Welding along the periphery of the predetermined region in the overlapped fixed portion so that the welded portion of the fixed portion of the terminal member and the fixed portion of the frame have a shape that opens a part of the peripheral shape of the predetermined region;
In this method, the open portion of the welded portion is used to form a communicating portion through which gas can flow out from the surrounding region surrounded by the fixing portion of the end member, the fixing portion of the frame, and the welding portion.

  According to such a configuration, even if gas such as air expands in the surrounding region surrounded by the welded portion, the fixing portion of the termination member, and the fixing portion of the frame, the gas flows out from the communicating portion, so that welding immediately after welding is performed. It is possible to prevent gas from being ejected from the part. Thereby, it is possible to prevent a hole or the like due to the ejection of the gas from occurring in the welded portion, and to obtain a power storage device with few weld defects in the welded portion.

  As described above, it is possible to provide a power storage device with few welding defects in the welded portion between the terminal member holding the power storage element and the frame, and a method for manufacturing the power storage device.

FIG. 1 is a perspective view of a power storage device according to an embodiment. FIG. 2 is a perspective view of a power storage element according to the power storage device according to the embodiment. FIG. 3 is a front view of the power storage element according to the power storage device according to the embodiment. FIG. 4 is an exploded perspective view of the power storage device according to the embodiment. FIG. 5 is a perspective view of the inner spacer, the outer spacer, and the power storage element of the power storage device according to the embodiment. FIG. 6 is an enlarged perspective view of a portion surrounded by a broken line in FIG. 1 and schematically showing a fixed portion, a welded portion, and a communicating portion. FIG. 7 is a schematic diagram schematically illustrating a state where the fixed portion is viewed from the outside to the inside of the power storage device. FIG. 8 is a cross-sectional view schematically showing the VIII-VIII cross section of FIG. FIG. 9 is a flowchart showing the steps of the method for manufacturing the power storage device. FIG. 10 is a diagram illustrating a specific example of the shape of the welded portion and the communication portion. FIG. 11 is a diagram showing another specific example of the shape of the welded portion and the communication portion. FIG. 12 is a diagram showing another specific example of the shape of the welded portion and the communication portion. FIG. 13 is a diagram showing another specific example of the shape of the welded portion and the communication portion. 14 is a cross-sectional view schematically showing the XIV-XIV cross section of FIG. FIG. 15 is a front view of a specific example of a conventional power storage device. FIG. 16 is an enlarged schematic view of a part of a conventional power storage device.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the name of each component (each component) of this embodiment is a thing in this embodiment, and may differ from the name of each component (each component) in background art.

  As shown in FIG. 1, the power storage device includes a power storage element 1, a spacer 2 adjacent to the power storage element 1, and a holding member 3 that holds the power storage element 1 and the spacer 2 together. The holding member 3 is formed of a conductive material. Accordingly, the power storage device includes an insulator 4 disposed between the power storage element 1 and the holding member 3.

  As shown in FIGS. 2 and 3, the power storage device 1 includes an electrode body including a positive electrode and a negative electrode, a case 10 that houses the electrode body, and a pair of external terminals 11 that are disposed on the outer surface of the case 10. .

  The case 10 includes a case main body 100 having an opening, and a cover plate 101 that closes the opening of the case main body 100, and a pair of external terminals 11 are disposed on the outer surface.

  The case main body 100 includes a closing part 100a (see FIG. 3) and a cylindrical body part 100b connected to the periphery of the closing part 100a so as to surround the closing part 100a.

  The trunk portion 100b includes a pair of first walls 100c that face each other with a space therebetween, and a pair of second walls 100d that face each other across the pair of first walls 100c.

  Each of the first wall 100c and the second wall 100d is formed in a rectangular shape. That is, each surface of the first wall 100c and the second wall 100d is a flat surface and is a quadrangular region. The trunk | drum 100b is formed in the square cylinder shape. One end of the trunk portion 100b is closed by the closing portion 100a. On the other hand, the other end of the trunk portion 100 b is opened and closed by the lid plate 101.

  In the present embodiment, the surface area of the first wall 100c is larger than the surface area of the second wall 100d. Accordingly, the body 100b is formed in a flat rectangular tube shape.

The power storage device according to the present embodiment includes a plurality of power storage elements 1. Each of the plurality of power storage elements 1 is aligned in one direction. In the present embodiment, each of the plurality of power storage elements 1 is aligned with the first wall 100c of the case 10 oriented in one direction. The power storage device includes a bus bar that electrically connects the external terminals 11 of two adjacent power storage elements 1.
In the following description, for convenience, the direction in which the electricity storage elements 1 are aligned is referred to as the X-axis direction. In addition, one of the two axial directions orthogonal to the direction in which the power storage elements 1 are aligned (X-axis direction) is referred to as a Y-axis direction, and the remaining one direction is referred to as a Z-axis direction. Accordingly, in FIG. 1, three orthogonal axes (coordinate axes) corresponding to the X-axis direction, the Y-axis direction, and the Z-axis direction are supplementarily illustrated.

  The spacer 2 has an insulating property. The spacer 2 will be described more specifically. The power storage device includes a plurality of power storage elements 1 as described above. Accordingly, the power storage device includes two types of spacers 2 (2A and 2B) as shown in FIG. That is, the power storage device includes, as spacers 2, a spacer (hereinafter referred to as an internal spacer) 2 </ b> A disposed between two power storage elements 1 and a spacer adjacent to the power storage element 1 at the end of the plurality of power storage elements 1. 2B (hereinafter referred to as an external spacer).

  As shown in FIG. 5, the inner spacer 2 </ b> A includes a base 20 </ b> A adjacent to the case main body 100 of the power storage element 1 and a restricting portion 21 </ b> A that prevents displacement of the two power storage elements 1 adjacent to the base 20 </ b> A. The inner spacer 2 </ b> A is disposed between two adjacent power storage elements 1. The restricting portion 21A is formed at each corner of the base 20A of the inner spacer 2A.

  Since the power storage device according to this embodiment includes a plurality of power storage elements 1 as described above, the internal spacers 2 </ b> A are disposed between the adjacent power storage elements 1. That is, the power storage device includes a plurality of internal spacers 2A.

  The external spacer 2B includes a base (hereinafter referred to as a base) 20B having a first surface facing the power storage element 1 (the first wall 100c of the case body 100) and a second surface opposite to the first surface, And a restricting portion (hereinafter referred to as a restricting portion) 21B that determines the position of the power storage element 1 adjacent to the base 20B. The base 20B of the outer spacer 2B and the terminal member 30 described later of the holding member 3 are opposed to each other. That is, the external spacer 2 </ b> B is disposed between the power storage element 1 and the termination member 30.

  The outer spacer 2B is a shaft portion 23B for determining the position of the termination member 30 with respect to the base 20B, and has a shaft portion 23B protruding from the second surface of the base 20B. The shaft portion 23B is inserted into an insertion hole 300a of the termination member 30 described later.

  As described above, the outer spacer 2 </ b> B according to the present embodiment is disposed adjacent to the inner spacer via the power storage element 1. That is, the power storage device includes a pair of external spacers 2B. The outer spacer 2 </ b> B is adjacent to the power storage element 1 at the end of the plurality of power storage elements 1. That is, a pair of external spacers 2B are provided so as to sandwich a plurality of aligned storage elements 1.

  Each of the pair of external spacers 2 </ b> B faces the case body 100 of the electricity storage device 1 as described above. Therefore, each of the pair of external spacers 2B is disposed such that the first surfaces of the bases 20B of the external spacers 2B face each other. Therefore, in the power storage device, each of the pair of external spacers 2B is disposed so as to be symmetrical with each other in the direction in which the plurality of power storage elements 1 are aligned (hereinafter referred to as the X-axis direction).

  In the present embodiment, the holding member 3 is made of metal. As shown in FIG. 4, the holding member 3 includes a pair of termination members 30 disposed at positions adjacent to the external spacers 2 </ b> B, and a frame 31 that connects each of the pair of termination members 30.

  Each of the pair of termination members 30 has a first surface facing the outer spacer 2B and a second surface opposite to the first surface. Each of the pair of termination members 30 includes a pressure contact portion 300 that contacts an external contact portion 24B extending from the base 20B of the external spacer 2B.

  Termination member 30 is formed in a shape (in this embodiment, a rectangular shape) corresponding to case 10 of power storage element 1 when viewed from one side in the X-axis direction.

  The end member 30 is disposed at a position corresponding to the cover plate 101 of the power storage element 1 and a second end opposite to the first end (at a position corresponding to the closing portion 100a of the power storage element 1). A second end). In addition, the termination member 30 includes a third end disposed at a position corresponding to the second wall 100d of the power storage element 1, and a fourth end opposite to the third end (the other end of the power storage element 1). Second wall 100d and a fourth end disposed at a corresponding position).

  Accordingly, the termination member 30 includes a first corner portion that is a portion where the first end and the third end are connected, and a second corner portion that is a portion where the first end and the fourth end are connected. Have Moreover, the termination | terminus member 30 has the 4th triangle part which is a part to which each of a 2nd end and a 4th end is connected, and the 4th triangle part which is a part to which a 2nd end and a 3rd end are connected. Have.

The termination member 30 has a plurality of fixing portions 301 connected to the frame 31. The fixing portion 301 has a facing surface facing the frame 31 and a surface opposite to the facing surface. The fixing portion 301 of the termination member 30 includes a first fixing portion 301a disposed at each of the first corner portion and the second corner portion, and a second fixing portion 301b disposed at each of the third triangular portion and the fourth corner portion. Have. The facing surface of the fixing portion 301 is included in the second surface of the termination member 30.
Moreover, the press-contact part 300 has the insertion hole 300a formed in the position corresponding to the axial part 23B of the external spacer 2B.

  The frame 31 is a pair of first connection portions 310 extending between the pair of termination members 30, and a pair of first connection portions 310 disposed at positions corresponding to the cover plate 101 of the power storage device 1, and a pair And a pair of second connection portions 311 extending between the end members 30 of the power storage device 1 and a pair of second connection portions 311 disposed at positions corresponding to the closing portions 100a of the power storage device 1.

  The frame 31 has a pair of support portions 312 that are connected to the first connection portion 310 and the second connection portion 311. The frame 31 includes a reinforcing portion 315 that is connected to the first connection portion 310 and the second connection portion 311. The frame 31 has a tongue piece 314 extending from the second connection portion 311.

  The frame 31 according to the present embodiment is formed in a frame shape by connecting the support portion 312 to the first connection portion 310 and the second connection portion 311. Accordingly, in the power storage device in the present embodiment, the first connection portion 310 and the second connection portion 311 that are arranged on one side of the power storage element 1 in a direction orthogonal to the X-axis direction (hereinafter referred to as the Y-axis direction). The member having the support portion 312 is a first connecting member 31A, and the first connection portion 310, the second connection portion 311 and the member having the support portion 312 are arranged on the other side of the power storage element 1 in the Y-axis direction. The following description may be given as the connecting member 31B.

  The reinforcing part 315 connects the first connection part 310 and the second connection part 311 as described above. Thereby, in the frame 31, the reinforcement part 315 prevents the first connection part 310 and the second connection part 311 from being deformed.

  The tongue piece 314 extends below the closing portion 100 a of the electricity storage device 1. Therefore, in the power storage device, the tongue piece 314 prevents the power storage element 1 from vibrating (vibrating in the Z-axis direction).

  Each of the pair of first connection portions 310 has a first end in a longitudinal direction and a second end opposite to the first end.

  Moreover, each of a pair of 1st connection part 310 is bent along the direction which makes a longitudinal direction. In each of the pair of first connection portions 310, one portion with the bent portion as a boundary is disposed at a position corresponding to the lid plate 101 of the electricity storage device 1. In each of the pair of first connection portions 310, the other with the bent portion as a boundary is disposed at a position corresponding to the second wall 100 d of the energy storage device 1.

  Each of the pair of second connection portions 311 has a first end and a second end opposite to the first end in a longitudinal direction.

  The second connection portion 311 is bent along the direction forming the longitudinal direction. The second connection portion 311 is arranged such that one part with the bent part as a boundary is disposed at a position corresponding to the cover plate 101 of the power storage element 1, and the other part with the bent part as a boundary is the second part of the power storage element 1. It arrange | positions in the position corresponding to the wall 100d.

  The support portion 312 includes a first support portion 312 a connected to the first end of the first connection portion 310 and the first end of the second connection portion 311, and a second end of the first connection portion 310 and the second connection portion 311. And a second support portion 312b connected to the second end.

  The frame 31 has a fixing portion 313 connected to the termination member 30. The fixing portion 313 has a facing surface facing the terminal member 30 and a surface opposite to the facing surface.

  Each frame 31 includes a pair of first fixing portions 313 a formed at the first end and the second end of the first connection portion 310, and a first end and a second end of the second connection portion 311 as the fixing portion 313. And a pair of second fixing portions 313b.

  One first fixing portion 313a overlaps with the fixing portion 301a arranged at one of the first corner portion and the second corner portion of the one end member 30. The other first fixing portion 313a overlaps with the fixing portion 301a arranged at the other corner portion of the first corner portion or the second corner portion of the other end member 30.

  The one second fixing portion 313b overlaps with the fixing portion 301b disposed at one corner of the first triangular member or the fourth corner of the one end member 30. The other second fixing portion 313b overlaps with the fixing portion 301b arranged at the other corner of the third triangular portion or the fourth corner of the other end member 30.

  The fixing portion 301 of the end member 30 and the fixing portion 313 of the frame 31 overlap so that their surfaces (opposing surfaces) face each other.

  The fixing portion 301 of the end member 30 and the fixing portion 313 of the frame 31 are welded. That is, the holding member 3 has a welded portion 32 in which the fixed portions 301 and 313 are welded along the periphery of a predetermined region in a state where the fixed portion 301 of the end member 30 and the fixed portion 313 of the frame 31 are overlapped. Have. For example, as shown in FIG. 7, the peripheral shape of the predetermined region is an oval shape having a pair of opposed arc portions and a pair of linear portions connecting the ends of the arc portions.

  In welding, a general welding method is employed. For example, laser welding using a YAG laser as a laser light source can be employed as the welding.

  The welded portion 32 is a laser beam from either side of the terminating member 30 or the frame 31 in a state where the fixing portion 301 of the terminating member 30 and the securing portion 313 of the frame 31 overlap each other (opposing surfaces). It is formed by irradiation with light or the like. Specifically, the irradiation is performed on a part of the fixed portions 301 and 313, and the irradiated fixed portion 301 of the terminal member 30 and the irradiated fixed portion 313 of the frame 31 are once melted. The welds 32 are formed by mixing and then solidifying.

  A part of the welded portion 32 is recessed from the flat portions on the surfaces of the fixed portions 301 and 313 (so-called bead formation). The welded portion 32 shown in FIGS. 6 and 7 is represented by a solid line in order to explain the shape of the welded portion 32 in detail.

  The welded portion 32 is formed to draw an annular line when viewed from one side in the thickness direction of the fixed portions 301 and 313. Both ends of the line drawn in an annular shape are in a non-contact state as shown in FIG.

  As shown in FIG. 6, the fixing portion 301 of the termination member 30 is disposed between the fixing portion 313 of the frame 31 and the power storage element 1. That is, the fixing portion 301 of the termination member 30 is disposed closer to the power storage element 1 than the fixing portion 313 of the frame 31.

  In addition, the holding member 3 includes a communication portion 33 that connects the surrounding region R surrounded by the fixing portion 301 of the end member 30, the fixing portion 313 of the frame 31, and the welding portion 32, and the outside of the surrounding region R. Have. For example, as shown in FIG. 7, the communication portion 33 is provided in an elliptical straight portion. Note that the surrounding region R is usually a very narrow region, but is emphasized and expressed as a relatively wide region in FIG.

  As shown in FIG. 7, the communication portion 33 is formed by a welded portion 32 having a shape in which a part of the peripheral shape of a predetermined region is opened. That is, the communication part 33 is constituted by an open part 33 b in the weld part 32.

  For example, as shown in FIG. 8, the termination member 30 includes a base material 355 and a metal layer 356 that is on the base material 355 and has a boiling point lower than the melting point of the base material 355.

  For example, the metal layer 356 of the fixing portions 301 and 313 is a plating layer formed by plating. The metal layer 356 of the fixing portions 301 and 313 is made of, for example, zinc. On the other hand, the base material 355 of the fixing parts 301 and 313 is made of, for example, a metal having a boiling point higher than that of zinc. The fixing portions 301 and 313 of the present embodiment are formed of galvanized steel plates. That is, the base material 355 is formed of steel that is an iron-based alloy, and the metal layer 356 is formed of zinc.

  The insulator 4 is made of an insulating material. The insulator 4 includes a pair of first insulating portions 40 disposed between each of the pair of first connection portions 310 and the spacer 2 (inner spacer 2A and outer spacer 2B), and a pair of second connection portions 311. It has a pair of 2nd insulation parts 41 arrange | positioned between each and the spacer 2 (inner spacer 2A and outer spacer 2B).

  The insulator 4 has a third insulating portion 42 that is connected to the first insulating portion 40 and the second insulating portion 41. Furthermore, the insulator 4 includes a fourth insulating portion 43 that is connected to a midpoint position of the first insulating portion 40 and a midpoint position of the second insulating portion 41. The insulator 4 has a fifth insulating part 44 extending from the second insulating part 41.

  Next, a method for manufacturing a power storage device for manufacturing the power storage device of the above embodiment will be described with reference to FIG.

  The storage elements 1 and the spacers 2 are alternately arranged, the plurality of storage elements 1 are aligned in the X-axis direction, and a pair of termination members 30 are disposed so as to sandwich the group of aligned storage elements 1 in the X-axis direction, In addition, the pair of frames 31 are arranged so as to sandwich the group of aligned power storage elements 1 in the Y-axis direction (step S1).

The fixing portion 301 of the termination member 30 disposed along the power storage element 1 in the Y-axis direction overlaps the fixing portion 313 of the frame 31 disposed along the power storage element 1 in the X-axis direction intersecting the Y-axis direction. (Step S2).
When the fixing portions 301 and 313 are overlapped with each other, the fixing portion 301 of the termination member 30 is disposed between the fixing portion 313 of the frame 31 and the power storage element 1.

Predetermined regions in the fixed portions 301 and 313 in an overlapped state so that the welded portion 32 between the fixing portion 301 of the end member 30 and the fixing portion 313 of the frame 31 is a part of the peripheral region of the predetermined region. Welding is performed along the peripheral edge (step S3).
For example, the welded portion 32 is formed by laser welding.

Gas can flow out of the surrounding region R from the surrounding region R surrounded by the fixing portion 301 of the end member 30, the fixing portion 313 of the frame 31, and the welding portion 32 by the opened portion 33 b in the welding portion 32. The communication part 33 is formed (step S4).
The communication part 33 may be formed by, for example, an open part in the welded part 32 by performing welding so that the welded part 32 has a shape in which a part of the peripheral shape of the predetermined region is opened.
Welding is performed so that the peripheral shape of the predetermined region is an oval shape having a pair of opposed arc portions and a pair of linear portions connecting the ends of the arc portions in the present embodiment. At this time, the communication part 33 is provided in a linear part.

  As described above, the power storage device of the present embodiment includes at least one power storage element 1 and the holding member 3 that holds the power storage element 1, and the holding member 3 is a terminal that is disposed along the power storage element 1. The end member 30 has a fixing part 301 joined to the frame 31, the frame 31 has a fixing part 313 joined to the end member 30, and a holding member 3 is a state in which the fixing portion 301 of the termination member 30 and the fixing portion 313 of the frame 31 are overlapped, and the welding portion 32 in which the fixing portions 301 and 313 are welded to each other along the peripheral edge of the predetermined region, and the termination member 30. A surrounding portion R surrounded by the fixing portion 301, the fixing portion 313 of the frame 31, and the welded portion 32, and a communication portion 33 that communicates the outside of the surrounding region R.

  When manufacturing the above power storage device, when welding the fixing portion 301 of the termination member 30 and the fixing portion 313 of the frame 31 during the manufacture of the power storage device, the welding portion 32 and the fixing portion 301 of the termination member 30 are used. Even if a gas such as air expands in the surrounding region R surrounded by the frame 31 and the fixing portion 313 of the frame 31, the gas flows out from the communication portion 33 to the outside. For this reason, it is possible to prevent gas from being ejected from the welded portion 32 immediately after welding during the manufacturing, thereby preventing a hole or the like due to the ejection of the gas from occurring in the welded portion 32, that is, the welded portion 32. Can prevent welding defects. For this reason, a high-quality power storage device can be obtained.

  When manufacturing the above power storage device, if the member to be welded has a metal layer 356 having a boiling point lower than the melting point of the base material 355 in the member, the metal layer is heated by the heat at the time of welding the member. The metal constituting 356 evaporates (vaporizes), that is, gas is generated. In the power storage device described above, since the communication portion 33 is provided, even if the metal constituting the metal layer 356 evaporates (vaporizes) due to heat generated when the termination member 30 and the frame 31 are welded during manufacturing, The gas metal (generated gas) flows out from the surrounding region R to the outside through the communication portion 33.

  For this reason, at least one of the fixing portions 301 and 313 of the fixing portion 301 of the termination member 30 and the fixing portion 313 of the frame 31 is the base material of either the fixing portion 301 of the termination member 30 or the fixing portion 313 of the frame 31. Even if the metal layer 356 having a boiling point lower than the melting point of 355 is provided, gas ejection (welding defect) in the welded portion 32 is reliably prevented. Thereby, a high-quality power storage device can be obtained.

The welded portion 32 of the power storage device has a shape in which a part of the peripheral shape of the predetermined region is opened, and the communicating portion 33 is configured by the opened portion 33 b in the welded portion 32.
As described above, by opening a part of the peripheral shape of the predetermined region, a configuration in which gas flows out from the surrounding region R is realized, and a power storage device with few welding defects is obtained.

In the above power storage device, the peripheral shape of the predetermined region is an oval shape having a pair of opposed arc portions and a pair of straight portions connecting the ends of the arc portions, and the communication portion 33 is a straight portion. Is provided.
According to such a configuration, both ends of the welded portion 32 face each other on a straight line when a force in a direction away from the fixed portion 301 of the overlapped termination member 30 and the fixed portion 313 of the frame 31 is applied. Therefore, it is possible to effectively prevent the stress from being concentrated on each end portion of the welded portion 32.

  The power storage element 1 expands and contracts with charge and discharge. When the power storage element 1 expands, at least one of the termination member 30 and the frame 31 disposed along the power storage element 1 is pushed by the power storage element 1, thereby, a welded portion between the termination member 30 and the frame 31. A force is applied to 32. When this force is applied to the welded portion 32 in the shearing direction, the welded portion 32 is easily broken compared to the case where a force is applied to the welded portion 32 in the compression direction. It cannot be secured.

  For this reason, in the power storage device, the fixed portion 301 of the termination member 30 is disposed between the fixed portion 313 of the frame 31 and the power storage element 1, thereby causing the expansion of the power storage element 1. The force applied to the welded portion 32 can be in the direction in which the welded portion 32 is compressed, and as a result, the strength of the welded portion 32 can be sufficiently ensured.

  Note that the power storage device and the method for manufacturing the power storage device according to the present invention are not limited to the above-described embodiments, and various changes are naturally made without departing from the scope of the present invention.

  In the said embodiment, the shape (shape along the periphery of a predetermined area | region) of the welding part 32 is an ellipse shape, as shown in FIG. However, the shape of the welded portion 32 is not limited to an oval shape, and may be, for example, a perfect circle shape, an elliptical shape, or a polygonal shape.

  In the said embodiment, the shape of the welding part 32 was a shape open | released when a part of peripheral shape of the predetermined area | region protruded outside. However, the shape of the welded portion 32 may be a shape that is opened when a part of the peripheral shape of the predetermined region enters inside as shown in FIG. 10, and the predetermined region as shown in FIG. It may be a shape opened by simply cutting off a part of the peripheral shape.

  In the above-described embodiment, the communication portion 33 is provided at a straight portion of the oval weld portion 32. However, the communication part 33 may be provided in the curved part of the ellipse-shaped weld part 32, as shown in FIG.

  In the above embodiment, at least one of the fixing portions 301 and 313 of the fixing portion 301 of the termination member 30 and the fixing portion 313 of the frame 31 has the metal layer 356, but the fixing portions 301 and 313 are The metal layer 356 may not be provided.

In the above embodiment, the communication portion 33 is configured by the opened portion 33 b in the weld portion 32. However, the communication part 33 is constituted by the through-hole 33a, and the part 33b opened to the weld part 32 may not be provided. That is, the welded part 32 may be formed so as to draw a closed annular line when viewed from one side in the thickness direction of the fixed parts 301 and 313.
Specifically, for example, as shown in FIGS. 13 and 14, the communication portion 33 is a through hole provided in at least one of the fixing portions 301 and 313 of the fixing portion 301 of the terminal member 30 and the fixing portion 313 of the frame 31. 33a, which may include a through hole 33a that communicates the surrounding region R with the outside of the surrounding region R.
The through hole 33 a can be provided in at least one of the fixing portion 301 of the termination member 30 and the fixing portion 313 of the frame 31. The through hole 33a penetrates at least one of the fixing portion 301 of the termination member 30 and the fixing portion 313 of the frame 31 in the thickness direction.
Since the communication portion 33 is configured by the through-hole 33a, a configuration in which gas flows out from the surrounding region R to the outside is realized by a simple configuration such as the through-hole 33a. Is obtained.

  In the above embodiment, the through hole 33a is formed in a circular shape when viewed from one side in the thickness direction of the fixing portions 301 and 313, but may be formed in a shape other than a circular shape such as a rectangular shape.

  In the above embodiment, the communication portion 33 is configured by one open hole 33 a and one open portion 33 b in the welded portion 32. However, the communication part 33 may be comprised by the some through-hole 33a. Moreover, the communication part 33 may be comprised by the some open | release site | part 33b in the welding part 32. FIG.

1: electricity storage element,
10: Case, 11: External terminal,
2: Spacer,
2A: inner spacer, 2B: outer spacer,
3: Holding member,
30: Termination member, 301: Fixing part of termination member,
31: Frame, 313: Fixed part of frame,
32: welded part,
33: Communication part
33a: a through hole, 33b: an open part in the weld,
355: Base material, 356: Metal layer 4: Insulator R: Surrounding area.

Claims (7)

At least one power storage element;
A holding member for holding the power storage element,
The holding member has a termination member disposed along the power storage element in a first direction, and a frame disposed along the power storage element in a second direction intersecting the first direction,
The termination member has a fixing portion joined to the frame,
The frame has a fixing portion to be joined to the terminal member,
The holding member is
In a state where the fixed portion of the termination member and the fixed portion of the frame are overlapped, a welded portion in which the fixed portions are welded along the periphery of the predetermined region;
A power storage device comprising: a fixing portion of the termination member; a fixing portion of the frame; and an enclosure region surrounded by the welded portion and a communication portion communicating the outside of the enclosure region.   At least one of the fixing part of the terminal member and the fixing part of the frame is a metal layer having a boiling point lower than the melting point of the base material of either the terminal member fixing part or the frame fixing part. The power storage device according to claim 1, comprising:   The communication portion is a through hole provided in at least one of the fixing portion of the termination member and the fixing portion of the frame, and the through hole communicates the surrounding region and the outside of the surrounding region. The power storage device according to claim 1, comprising: The welded portion has a shape in which a part of the peripheral shape of the predetermined region is opened,
The power storage device according to claim 1, wherein the communication portion is configured by the opened portion in the weld portion. The peripheral shape of the predetermined region is an oval shape having a pair of opposing arc portions and a pair of straight portions connecting the ends of the arc portions,
The power storage device according to claim 4, wherein the communication part is provided in the straight line part.   6. The power storage device according to claim 1, wherein the fixing portion of the termination member is disposed between the fixing portion of the frame and the power storage element. The fixing portion of the termination member arranged along the electricity storage element in the first direction and the fixing portion of the frame arranged along the electricity storage element in the second direction intersecting with the first direction,
Along the periphery of the predetermined region in the overlapped fixed portion so that the welded portion between the fixed portion of the termination member and the fixed portion of the frame has a shape in which a part of the peripheral shape of the predetermined region is opened. Welding
The open portion of the welded portion forms a fixed portion of the end member, a fixed portion of the frame, and a communication portion that allows gas to flow out of the enclosed region surrounded by the welded portion. A method for manufacturing a power storage device.

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