JP5900128B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device.

  Conventionally, as a secondary battery which is a kind of power storage device, for example, a lithium ion secondary battery or a nickel-hydrogen secondary battery is well known. In such a secondary battery, an electrode assembly in which an electrode sheet obtained by applying an active material to a metal sheet is layered, and an external terminal member that is formed outside the case and extracts power is electrically connected by a connecting member. (For example, patent document 1).

  In the terminal of Patent Document 1, a shaft portion of the external terminal member is formed with a screw portion disposed outside the case and a base end portion connected to the connection member inside the case. This external terminal member is a case in which the gasket sandwiched between the hole formed in the case and the external terminal member is compressed and deformed by screwing and tightening a nut to the screw portion, and the sealing property is secured. It is fixed to.

  And in patent document 1, while forming an external terminal member from aluminum, while reducing an electrical resistance, the intensity | strength of a screw part is improved by performing an alumite process on the surface. For this reason, in patent document 1, it is suppressing that the screw part of an external terminal member is damaged when tightening a nut strongly, reducing the electrical resistance in a terminal.

JP-A-2005-71847

  However, in Patent Document 1, the surface hardness of the external terminal member is merely increased. For this reason, in Patent Document 1, for example, when the nut is strongly tightened to improve the sealing performance, the external terminal member is tightened in the axial direction (tightening axial force) generated by tightening the nut. The terminal member cannot be sufficiently prevented from breaking.

  In order to avoid such a problem, the external terminal member and the connection member are fixed to the case with a fixing member (for example, a stud bolt) made of a metal having higher strength than the metal forming the connection member or the external terminal member. It is also conceivable to electrically connect the external terminal member and the connecting member. Here, the metal for forming the fixing member can be selected from a plurality of types of metals based on viewpoints such as workability and cost as the fixing member. However, when a metal having a lower conductivity than the connection member or the external terminal member is selected as the metal forming the fixing member, the strength of the fixing member can be improved, but there is a problem that the electrical resistance is increased. For this reason, it is expected not only to improve the strength, but also to suppress an increase in electrical resistance regardless of the type of metal forming the connection member. Such a problem also occurs in an electric double layer capacitor, for example.

  The present invention has been made paying attention to the problems existing in the above-described conventional technology, and an object of the present invention is to provide a power storage device capable of suppressing an increase in electrical resistance while improving strength.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a case, an electrode assembly accommodated in the case, an external terminal portion formed outside the case, made of metal, and having an insertion hole. The external terminal portion is made of the same metal and is electrically connected to the electrode assembly inside the case, a fixing portion for fixing the external terminal portion, the external terminal portion and the connection portion. A conductive portion having an insertion hole, wherein the fixing portion, the external terminal portion, and the connecting portion are insulated from the wall of the case, and the fixing portion is the external terminal And a shaft portion made of a metal having higher strength than the connection portion, the case has a terminal wall through which the shaft portion penetrates, and the shaft portion serves as an insertion hole of the external terminal portion. One side that is inserted and the external terminal portion is connected to one end side The connecting portion is connected to the other end side, the external terminal portion and the connecting portion are fixed to the terminal wall by the fixing portion, the conductive portion penetrates the terminal wall, and the external portion is connected to the one end side. The terminal portion is connected in surface contact, while the connection portion is connected to the other end side, and the external terminal portion and the connection portion are made of the same metal and extend along the axial direction of the shaft portion. The shaft portion is inserted through the insertion hole of the conductive portion, and the shaft portion is inserted through the insertion hole of the external terminal portion and the insertion hole of the conductive portion. The gist is that the diameter of the location is the same.

  According to this, the fixed portion has a shaft portion made of a metal having higher strength than the external terminal portion and the connection portion, and the other end side of the shaft portion is connected to the external terminal portion on one end side. The connection part is coupled to the external terminal part and the connection part are fixed to the terminal wall. For this reason, the intensity | strength in the fixing | fixed part which fixes an external terminal part and a connection part to a case can be improved. The conductive portion extends along the axial direction of the shaft portion and penetrates the terminal wall. The external terminal portion is connected to one end side, the connection portion is connected to the other end side, and the external terminal portion and the connection portion are electrically connected. It is connected. And this conductive part consists of the same metal as an external terminal part and a connection part. For this reason, a conductive path made between the external terminal portion and the connecting portion is formed by the conductive portion made of the same metal as the external terminal portion and the connecting portion, and the metal whose conductivity is lower than that of the external terminal portion and the connecting portion. Even if it is a case where it forms by, it can suppress that an electrical resistance becomes high. Therefore, it is possible to suppress an increase in electrical resistance while improving the strength.

In order to solve the above-mentioned problem, the invention according to claim 2 includes a case, an electrode assembly accommodated in the case, an external terminal portion formed of metal formed outside the case, and the external terminal portion. And a connection part electrically connected to the electrode assembly inside the case, a fixing part for fixing the external terminal part, and an electrical connection between the external terminal part and the connection part. A conductive portion, wherein the fixing portion, the external terminal portion, and the connecting portion are insulated from the wall of the case, and the fixing portion has a strength higher than that of the external terminal portion and the connecting portion. The case has a shaft portion made of a high metal, the case has a terminal wall through which the shaft portion penetrates, and the shaft portion is connected to the external terminal portion on one end side and the terminal portion on the other end side. A connection part is connected, and the external terminal part and the connection part are The fixing portion is fixed to the terminal wall, the conductive portion penetrates the terminal wall, the external terminal portion is connected to one end side, the connection portion is connected to the other end side, and the external portion The terminal portion and the connection portion are made of the same metal and extend along the axial direction of the shaft portion, and the terminal wall includes an insulating member disposed on the electrode assembly side, and the connection portion Includes a connecting portion connected to the shaft portion inside the case, and a current collecting member formed separately from the connecting portion and electrically connected to the electrode assembly. The electrical member is formed with a first contact surface that contacts the insulating member and a second contact surface that is opposite to the first contact surface and contacts the connecting portion. The gist is that the member is sandwiched between the insulating member and the connecting portion.

According to this, the fixed portion has a shaft portion made of a metal having higher strength than the external terminal portion and the connection portion, and the other end side of the shaft portion is connected to the external terminal portion on one end side. The connection part is coupled to the external terminal part and the connection part are fixed to the terminal wall. For this reason, the intensity | strength in the fixing | fixed part which fixes an external terminal part and a connection part to a case can be improved. The conductive portion extends along the axial direction of the shaft portion and penetrates the terminal wall. The external terminal portion is connected to one end side, the connection portion is connected to the other end side, and the external terminal portion and the connection portion are electrically connected. It is connected. And this conductive part consists of the same metal as an external terminal part and a connection part. For this reason, a conductive path made between the external terminal portion and the connecting portion is formed by the conductive portion made of the same metal as the external terminal portion and the connecting portion, and the metal whose conductivity is lower than that of the external terminal portion and the connecting portion. Even if it is a case where it forms by, it can suppress that an electrical resistance becomes high. Therefore, it is possible to suppress an increase in electrical resistance while improving the strength. The current collecting member electrically connected to the electrode assembly is in contact with the insulating member formed on the terminal wall of the case at the first contact surface, and is a surface opposite to the first contact surface. The two contact surfaces are in contact with the connecting portion connected to the shaft portion, and the current collecting member is sandwiched between the insulating member and the connecting portion of the case. Therefore, it can suppress that the electrical resistance in the contact part of a current collection member and a connection part becomes high.
According to a third aspect of the present invention, in the power storage device according to the first aspect, the terminal wall has an insulating member disposed on the electrode assembly side, and the connection portion has an inside of the case. A connecting portion connected to the shaft portion; and a current collecting member formed separately from the connecting portion and electrically connected to the electrode assembly, wherein the current collecting member includes the insulating member And a second contact surface that is opposite to the first contact surface and that contacts the connecting portion, and the current collecting member includes the insulating member and the first contact surface. The gist is that it is clamped by the connecting portion.

According to a fourth aspect of the present invention, in the power storage device according to the second or third aspect , the fixed portion is a shaft coupling portion disposed on the side opposite to the second contact surface side in the coupling portion. A male screw portion is formed on one of the shaft portion and the shaft coupling portion, and a female screw portion is formed on the other of the shaft portion and the shaft coupling portion. The gist is that the male screw portion and the female screw portion are screwed together.

According to this, a shaft part and a connection part can be easily connected by screwing a male screw part and a female screw part.
The gist of a fifth aspect of the present invention is the power storage device according to the fourth aspect , further comprising a regulating portion that regulates the shaft coupling portion from rotating with the rotation of the shaft portion.

According to this, it can suppress that a shaft connection part rotates with rotation of a shaft part. Therefore, the male screw portion and the female screw portion can be easily screwed together by rotating the shaft portion.
According to a sixth aspect of the present invention, in the power storage device according to the fifth aspect , the restricting portion includes a first restricting portion formed in the connecting portion, and a second restricting portion formed in the shaft connecting portion. The first restricting portion and the second restricting portion are configured to rotate in the shaft connecting portion by restricting the rotation of the shaft connecting portion by abutting in a direction orthogonal to the axial direction of the shaft portion. The gist is to regulate

  According to this, the 1st control part formed in the connection part and the 2nd control part formed in the shaft connection part contact | abut in the direction orthogonal to the axial direction of a shaft part. Therefore, the rotation of the shaft coupling portion accompanying the rotation of the shaft portion can be reliably restricted.

According to a seventh aspect of the present invention, in the power storage device according to the sixth aspect , the first restricting portion is a recess formed in the connecting portion, and the second restricting portion is formed in the shaft connecting portion. The gist is that the outer wall surface is in contact with the inner wall surface of the recess to restrict the rotation of the shaft coupling portion. According to this, rotation of the shaft coupling portion accompanying rotation of the shaft portion can be suitably restricted with a simple configuration.

A gist of an eighth aspect of the present invention is the power storage device according to any one of the second to seventh aspects, wherein the connecting portion and the conductive portion are integrally formed.
According to this, while being able to form a connection part and an electroconductive part easily, an electrical resistance can be restrained low compared with the case where a connection part and an electroconductive part are formed in a different body.

The invention according to claim 9 is the power storage device according to any one of claims 1 to 8 , wherein the power storage device is a secondary battery. According to this, as a secondary battery, strength can be improved while suppressing an increase in electrical resistance.

  According to the present invention, the strength can be improved while suppressing an increase in electrical resistance.

The perspective view which shows a secondary battery typically. The disassembled perspective view which shows an electrode assembly typically. AA sectional view taken on the line in FIG. The disassembled perspective view which shows a secondary battery typically. The perspective view which shows typically the state which looked at the secondary battery disassembled partially from the lower surface side. The perspective view which shows typically the secondary battery in another embodiment. The perspective view which shows typically the electrode assembly in another embodiment. BB sectional drawing shown in FIG.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, a secondary battery 10 as a power storage device mounted on a vehicle (for example, an industrial vehicle or a passenger vehicle) includes a case 11 having a flat and substantially rectangular parallelepiped shape as a whole. The case 11 is formed of a wall portion 12a having a rectangular flat plate shape when viewed from the front, and four wall portions 12b extending at right angles from the respective edge portions of the wall portion 12a, and one end thereof is sealed with the wall portion 12a as a whole. A main body member 12 having a cylindrical shape (in this embodiment, a flat rectangular cylindrical shape) is provided. The case 11 includes a lid member 13 that is assembled to the main body member 12 and seals (closes) the opening 12c of the main body member 12 (in this embodiment, a rectangular flat plate). The main body member 12 and the lid member 13 are both made of metal (for example, stainless steel or aluminum). In the following description, the longitudinal direction of the case 11 indicated by the arrow Y1 is indicated as the left-right direction, the height direction of the case 11 indicated by the arrow Y2 is indicated as the vertical direction, and the short direction of the case 11 indicated by the arrow Y3 is indicated as the front-back direction. Show.

  Further, in the case 11 (main body member 12), an electrode in which the positive electrode sheet 21 and the negative electrode sheet 22 form a layered structure (laminated structure) with a sheet-like separator (diaphragm) 23 sandwiched therebetween (intervened state). The assembly 25 is housed (stored). The electrode assembly 25 has a rectangular parallelepiped shape (substantially rectangular parallelepiped shape) flat in the left-right direction as a whole, and supplies electric power stored by charging. The electrode assembly 25 is accommodated in the case 11 while being covered with an insulating bag (not shown) made of an insulating material. The case 11 is filled with an electrolyte (electrolyte) according to the type of the secondary battery 10 such as a lithium ion secondary battery or a nickel hydride secondary battery.

  As shown in FIG. 2, the positive electrode sheet 21 and the negative electrode sheet 22 include a metal foil 26 as a thin metal plate (metal sheet) having a rectangular sheet shape. The metal foil 26 is formed of a metal corresponding to the type of the secondary battery 10 such as a lithium ion secondary battery or a nickel hydride secondary battery. The metal used for the metal foil 26 is different between the positive electrode sheet 21 and the negative electrode sheet 22. In the present embodiment, the metal foil 26 of the positive electrode sheet 21 is made of aluminum, while the metal foil 26 of the negative electrode sheet 22 is made of copper.

  Except for the non-application area | region 26b as an uncoated part set by the fixed width over the full width of the left-right direction from the upper end 26a used as one side of each metal foil 26 on both surfaces (front surface and rear surface) of each metal foil 26 The active material is applied to the entire surface, and the active material layer 27 is formed. That is, the non-application area 26 b extends along the upper end 26 a of the metal foil 26. Note that an active material corresponding to the type of the secondary battery 10 is applied to the metal foil 26. The active material applied to the metal foil 26 is different between the positive electrode sheet 21 and the negative electrode sheet 22.

  In the upper end 26a of each positive electrode sheet 21, on the right side from the center in the left-right direction, a non-application region 26b is punched to form a rectangular (substantially rectangular) positive lead 21a extending upward (the lid member 13). ing. Also, on the left side of the upper end 26a of each negative electrode sheet 22 from the center in the left-right direction, a non-application region 26b is punched to form a rectangular (substantially rectangular) negative lead 22a extending upward (the lid member 13). Is formed. For this reason, the active material layer 27 is not formed on the surfaces of the positive electrode lead 21a and the negative electrode lead 22a, and forms a part of the aforementioned uncoated portion. The separator 23 is made of an insulating resin material and is a rectangular porous sheet having an extremely fine pore structure. The separator 23 is interposed between the positive electrode sheet 21 and the negative electrode sheet 22 to insulate the positive electrode sheet 21 and the negative electrode sheet 22 from each other.

  The electrode assembly 25 is layered by laminating a plurality of positive electrode sheets 21 and negative electrode sheets 22 in the front-rear direction (thickness direction) with the separator 23 sandwiched between the positive electrode sheet 21 and the negative electrode sheet 22. Formed. Specifically, in the electrode assembly 25, the positive electrode sheet 21 and the negative electrode sheet 22 are alternately arranged in the order of... → positive electrode sheet 21 → negative electrode sheet 22 → positive electrode sheet 21. In the present embodiment, the front-rear direction indicated by the arrow Y <b> 3 is the stacking direction of the positive electrode sheet 21 and the negative electrode sheet 22 in the electrode assembly 25.

  As a result, as shown in FIG. 1, at the upper end of the electrode assembly 25, on the right side of the center in the left-right direction, the positive electrode current collector 28 that forms a layer with the positive electrode lead 21a sandwiching the separator 23 therebetween is It is formed to extend toward. Further, on the left side of the upper end of the electrode assembly 25 on the left side of the center in the left-right direction, a negative electrode current collector portion 29 is formed so as to extend upward, with the negative electrode lead 22a forming a layered state with no separator 23 interposed therebetween. . That is, the positive electrode current collector 28 and the negative electrode current collector 29 are spaced apart from each other along the extending direction of the non-coating region 26b at the upper end of the electrode assembly 25. It is formed at the center (substantially the center).

  As shown in FIG. 3, the positive electrode current collector 28 (positive electrode lead 21 a) is formed outside the case 11 (wall portion 12 b) and is made of metal (aluminum in the present embodiment). And are electrically connected. The negative electrode current collector 29 (negative electrode lead 22a) is electrically connected to a negative electrode external terminal 30 made of metal (copper in this embodiment) formed outside the case 11 (wall portion 12b). Yes.

  In the present embodiment, the connection structure between the positive electrode current collector 28 and the positive external terminal part 30 is bilaterally symmetrical to the connection structure between the negative electrode current collector 29 and the negative external terminal part 30. Therefore, in the following description, the junction structure between the positive electrode current collector 28 and the positive external terminal part 30 will be mainly described in detail, and the connection structure between the negative electrode current collector 29 and the negative external terminal part 30 will be described. The description is omitted or simplified by attaching the same reference numerals.

  As shown in FIG. 3, the positive electrode current collector 28 is made of the same metal as the metal (aluminum) forming the metal foil 26 of the positive electrode sheet 21 and the external terminal portion 30 for the positive electrode, and has a rectangular flat plate shape in plan view. The current collecting member 31 is joined and electrically connected to one end (base end) side. Here, the “same metal” in this specification does not intend only a metal having the completely same composition. For example, the main composition is the same, such as aluminum and an aluminum alloy, or copper and a copper alloy. The metal which is is also included.

  More specifically, as shown in FIGS. 4 and 5, the current collecting member 31 is disposed opposite to the upper end (each upper end 26 a) of the electrode assembly 25 inside the case 11. Each positive electrode lead 21 a constituting the positive electrode current collector 28 is bent along a surface (lower surface) of the current collector 31 that faces the electrode assembly 25. Then, the positive electrode current collector 28 is a state in which the positive electrode leads 21a constituting the positive electrode current collector 28 are gathered, and the surface of the current collector 31 facing the electrode assembly 25 is subjected to, for example, ultrasonic welding or Joined by resistance welding.

  As shown in FIGS. 3 and 4, on the other end (tip) side of the current collecting member 31, from the edge on the wall 12 a side disposed on the side opposite to the opening 12 c, toward the opening 12 c. An extending cutout 31a is formed. A conductive portion 32 having a cylindrical shape (substantially cylindrical shape) is engaged with the notch portion 31a. In the conductive portion 32, a connecting portion 33 that forms a flat rectangular shape (substantially rectangular parallelepiped shape) along the upper end (each upper end 26 a) of the electrode assembly 25 is connected to the end portion (lower end portion) on the electrode assembly 25 side. It is installed. In the present embodiment, the lower surface 31b as the second contact surface disposed on the electrode assembly 25 side of the current collecting member 31 is the opposite surface of the lower surface disposed on the electrode assembly 25 side of the connecting portion 33 ( The top surface is in contact with and in surface contact. The connecting portion 33 is formed separately from the current collecting member 31.

  As shown in FIGS. 3 and 5, the connecting portion 33 is formed with a recess 33 a that forms a rectangular parallelepiped space that opens in a square shape when viewed from below on the lower surface disposed on the electrode assembly 25 side. An insertion hole 32a formed by the conductive portion 32 is opened in the ceiling portion of the recess 33a. That is, the insertion hole 32a penetrates the conductive portion 32 and the connecting portion 33 in the vertical direction. In the present embodiment, the current collecting block 35 is formed by the conductive portion 32 and the connecting portion 33 that are integrated. The current collecting block 35 (conductive portion 32 and connecting portion 33) of the present embodiment is formed from the same metal (aluminum in the present embodiment) as the metal foil 26 of the positive electrode sheet 21 and the external terminal portion 30 for the positive electrode. .

  Further, a fixing nut 34 as a shaft connecting portion having a rectangular parallelepiped shape (substantially rectangular parallelepiped shape) is fitted and accommodated in the recess 33a. That is, the fixing nut 34 is disposed on the side opposite to the lower surface 31 b of the current collecting member 31 in the connecting portion 33. The fixing nut 34 is formed of another metal (iron in this embodiment) having a higher tensile strength than the metal (aluminum in this embodiment) forming the current collecting member 31 and the current collecting block 35.

  As shown in FIG. 5, in the state accommodated in the recessed part 33a, the side wall surface 34a as an outer wall surface of the fixing nut 34 is in contact with the inner wall surface 33b of the recessed part 33a facing each other. As shown in FIG. 4, the fixing nut 34 has a screw hole 34 b as a female screw portion that communicates a lower surface disposed on the electrode assembly 25 side and a surface (upper surface) opposite to the electrode assembly 25. Is formed.

  Further, as shown in FIG. 4, the wall portion 12b of the main body member 12 facing the opposite surface (upper surface 31c) of the lower surface 31b of the current collecting member 31 has a rectangular shape in plan view. A hole 12d that communicates the outside and the inside of 11 is formed. The hole 12d is made of an insulating material (for example, a resin material), and has an insulating member that is flattened in the surface direction of the current collecting member 31 (in this embodiment, is a square tube with a heaven). A current collecting terminal holder 37 is assembled. In the present embodiment, the wall portion 12b facing the opposite surface (upper surface 31c) of the lower surface 31b of the current collecting member 31 and provided with the hole 12d serves as a terminal wall.

  In the current collecting terminal holder 37, the flat plate-shaped top plate portion 37 a arranged along the wall portion 12 b is aligned with the hole portion 12 d of the case 11 in plan view at the center in plan view so as to match the electrode assembly 25. A hole 37b is formed to communicate the lower surface arranged on the side and the opposite surface (upper surface). And the current collection block 35 and the current collection member 31 are assembled | attached to the current collection terminal holder 37 in the state which pinched | interposed the current collection member 31 between the top-plate part 37a and the current collection block 35 (connection part 33). Is housed. In the present embodiment, of the current collecting member 31, the upper surface 31 c as the first contact surface that is the opposite surface of the lower surface 31 b abuts on the top plate portion 37 a of the current collecting terminal holder 37 formed on the case 11. In surface contact. In this manner, the current collecting member 31 is sandwiched between the current collecting terminal holder 37 (top plate portion 37a) and the current collecting block 35 (connecting portion 33).

  Further, an external terminal holder 38 made of an insulating material (for example, a resin material) and having an annular shape in a plan view is assembled on the outer surface of the wall portion 12b of the main body member 12, and the hole portion 12d is formed in a plan view. The outer terminal holder 38 surrounds the outer terminal holder 38. The external terminal holder 38 is assembled with the positive external terminal portion 30 with an O-ring 39 made of an insulating material interposed therebetween. The external terminal portion 30 has an annular shape having an insertion hole 30a in the center in plan view, and the insertion hole 30a is a hole portion in plan view when the external terminal portion 30 is assembled to the external terminal holder 38. 12d is consistently matched.

  The external terminal portion 30 for the positive electrode is assembled to the main body member 12 (hole 12d) with the external terminal holder 38 and the O-ring 39 sandwiched between them by a stud bolt 40 having a substantially cylindrical shape extending in the vertical direction as a whole. It has been. More specifically, the stud bolt 40 includes a male screw portion and a shaft portion that are suspended from the lower surface disposed on the electrode assembly 25 side of the nut portion 40a having a hexagonal flat plate shape in plan view. 1 screw part 40b and the 2nd screw part 40c projected and formed from the opposite surface (upper surface) of the lower surface among nut parts 40a are provided. The stud bolt 40 of this embodiment is a different type of metal (iron in this embodiment) having a higher tensile strength than the metal (the aluminum in this embodiment) that forms the current collecting member 31, the current collecting block 35, and the external terminal portion 30. Formed from.

  As shown in FIG. 3, the nut portion 40 a that forms part of the stud bolt 40 faces the external terminal portion 30. The stud bolt 40 has a first screw portion 40 b inserted through the insertion hole 30 a of the external terminal portion 30, the hole portion 37 b (hole portion 12 d) of the current collecting terminal holder 37, and the insertion hole 32 a of the conductive portion 32. At the same time, it is screwed (threaded) into the screw hole 34 b of the fixing nut 34. Therefore, the external terminal portion 30, the O-ring 39, the external terminal holder 38, the wall portion 12b of the main body member 12, the top plate portion 37a of the current collecting terminal holder 37, the current collecting member 31, and the current collecting block 35 (the conductive portion 32). And the connecting portion 33) are sandwiched between the nut portion 40a and the fixing nut 34 in this order.

  That is, the stud bolt 40 is driven by the fastening axial force (tightening axial force) along the axial direction (vertical direction in the present embodiment) of the stud bolt 40 generated by screwing the first screw portion 40b into the fixing nut 34. The current collecting member 31, the current collecting block 35 (the conductive portion 32 and the connecting portion 33), and the external terminal portion 30 are fixed to the main body member 12 (wall portion 12b). In this state, the front end surface (upper surface) of the conductive portion 32 extending along the axial direction of the first screw portion 40b is in surface contact with the lower surface of the external terminal portion 30 disposed on the electrode assembly 25 side. Yes. Therefore, the stud bolt 40 (first screw portion 40b) and the conductive portion 32 penetrate the wall portion 12b, and the conductive portion 32 extends along the first screw portion 40b. In the present embodiment, the stud bolt 40 and the fixing nut 34 constitute a fixing portion.

  As described above, in the secondary battery 10 of the present embodiment, the current collecting member 31 connected to the positive electrode current collector 28 and the connecting portion 33 of the current collector block 35 are in contact (surface contact), and the current collector The front end surface of the conductive portion 32 of the electric block 35 and the external terminal portion 30 are in contact (surface contact). In other words, the external terminal portion 30 is connected to the nut portion 40a side which is one end side (base end side) of the first screw portion 40b, while the other end side (distal end side) of the first screw portion 40b. ) Is connected to the connecting portion 33 inside the case 11. And the current collection member 31 and the external terminal part 30 are electrically connected through the current collection block 35 (the connection part 33 and the electroconductive part 32).

  The external terminal portion 30, the current collecting member 31, the current collecting block 35 (the conductive portion 32 and the connecting portion 33), and the stud bolt 40 are isolated from the main body member 12 by the current collecting terminal holder 37 and the external terminal holder 38 made of an insulating material. It is insulated from the wall portion 12b of the main body member 12.

  As shown in FIG. 4, a disc-shaped washer 42 having an insertion hole 42 a communicating with the upper surface and the lower surface is inserted into the second screw portion 40 c of the stud bolt 40, and a hexagon nut 43 is screwed together. ing.

  In the present embodiment, the connecting portion 36 is configured by the connecting portion 33 of the current collecting member 31 and the current collecting block 35. Moreover, in the secondary battery 10 of this embodiment, the electrode assembly 25, the external terminal part 30, the current collection member 31, the current collection block 35, the external terminal part 30, the fixing nut 34, the current collection terminal holder 37, the external terminal holder 38, the O-ring 39, and the stud bolt 40 are respectively formed as a positive terminal 52 as a terminal and a negative terminal 53 as a terminal. The current collecting member 31 and the current collecting block 35 (the conductive portion 32 and the connecting portion 33) connected to the negative electrode current collecting portion 29 are made of the same metal (copper in this embodiment) as the external terminal portion 30 for the negative electrode. Become.

  In addition, when the battery module 50 is configured by arranging (stacking) a plurality of secondary batteries 10 as shown in FIG. 1, for example, the external terminal portion 30 for the positive electrode and the negative electrode between the adjacent secondary batteries 10. The external terminal portion 30 is electrically connected by a bus bar 51 made of metal (for example, aluminum).

  As shown in FIGS. 1 and 3, the bus bar 51 has a substantially rectangular flat plate shape that extends along the direction in which the secondary batteries 10 are juxtaposed (front-rear direction) in plan view, and on the side of the secondary battery 10. The wall portion is suspended from the edge portion of the lower surface to be disposed over the entire circumference. In addition, insertion holes 51 a through which the second screw portions 40 c of the stud bolts 40 are inserted are formed at both ends of the bus bar 51.

  The bus bar 51 is inserted through the second screw portion 40c in the order of the insertion hole 51a of the bus bar 51 and the insertion hole 42a of the washer 42, and the external terminal portion is screwed into the second screw portion 40c. 30 is fixed. In this state, in the bus bar 51, the front end surface (lower end surface) of the wall portion formed on the lower surface of the bus bar 51 is brought into surface contact with the surface (upper surface) opposite to the electrode assembly 25 in the external terminal portion 30, respectively. The terminal unit 30 is electrically connected.

Next, the operation of the secondary battery 10 configured as described above will be described.
In addition, since the positive electrode terminal 52 and the negative electrode terminal 53 have the same operation, the operation and effect of the positive electrode terminal 52 will be described in detail, and the description of the operation of the negative electrode terminal 53 will be omitted.

  As shown in FIG. 3, in the secondary battery 10 of the present embodiment, the connection part 36 (the current collecting member 31 and the connection part 33) that is electrically connected to the electrode assembly 25 and the outside of the case 11 are formed. The positive external terminal portion 30 is connected to the connection portion 36 and a first screw portion 40 b made of iron having higher tensile strength than aluminum forming the external terminal portion 30, and is fixed to the main body member 12. For this reason, in the positive electrode terminal 52, the strength of the stud bolt 40 that fixes the external terminal portion 30, the current collecting member 31, and the connecting portion 33 to the case 11 can be improved.

  More specifically, in the secondary battery 10 of the present embodiment, the external terminal portion 30, the current collecting member 31, and the current collecting block 35 are formed by screwing the first screw portion 40 b of the stud bolt 40 into the fixing nut 34. The O-ring 39 can be compressed and deformed to secure a high sealing performance, while being fixed to the main body member 12. In such a case, a large fastening axial force is generated in the first screw portion 40b. However, in the secondary battery 10 of the present embodiment, the stud bolt 40 is formed from a metal (iron) having a high tensile strength. The stud bolt 40 is suitably suppressed from being damaged by the fastening axial force.

  Moreover, in the secondary battery 10 of this embodiment, the connection part 33 and the external terminal part 30 are electrically connected by the electroconductive part 32 extended along the 1st screw part 40b. As described above, since the conductive portion 32 is formed of the same metal (aluminum) as the connection portion 36 (the current collection member 31 and the connection portion 33) and the external terminal portion 30, the current collection member 31 and the connection portion 32 are connected. In the connection part with the part 33 and the external terminal part 30, it can suppress that another kind of metal adjoins, and can suppress that electrical resistance becomes high by corrosion etc.

  And in the secondary battery 10 of this embodiment, as shown by arrow Y4, apart from the stud bolt 40, a metal (this book) that is more conductive than the metal that forms the stud bolt 40 (iron in this embodiment). In the embodiment, aluminum is used to form a conductive path that connects the current collecting member 31 and the external terminal portion 30. Therefore, it is possible to suitably suppress an increase in electrical resistance between the current collecting member 31 and the external terminal portion 30.

  Here, the metal (metal material) for forming the stud bolt 40 can be selected from a plurality of types of metals based on the workability and cost of the stud bolt 40. However, as in this embodiment, the stud bolt 40 is formed of a metal (iron in this embodiment) having a lower conductivity than the metal (aluminum or copper in this embodiment) forming the connection portion 36 and the external terminal portion 30. In this case, although the strength of the stud bolt 40 can be improved, the electrical resistance is increased. For this reason, when connecting the external terminal part 30 and the connection part 36 only by the stud bolt 40, the problem that the electrical resistance in the positive electrode terminal 52 or the negative electrode terminal 53 becomes high arises.

  In this embodiment, apart from the stud bolt 40, the conductive path is formed by the conductive portion 32 made of the same metal (aluminum or copper in the present embodiment) as the connecting portion 36 and the external terminal portion 30. Therefore, an increase in electrical resistance between the connection portion 36 and the external terminal portion 30 is preferably suppressed.

  Moreover, the stud bolt 40 of this embodiment is formed with the metal (iron in this embodiment) which is an electroconductive material. Therefore, in the present embodiment, the stud bolt 40 can function as an auxiliary conductive path, and the electrical resistance between the connection portion 36 and the external terminal portion 30 can be further reduced. Thus, in the secondary battery 10 of the present embodiment, it is possible to achieve both reduction in electrical resistance at the connection portion between the connection portion 36 and the external terminal portion 30 and improvement in tensile strength.

  The fixing nut 34 into which the first screw portion 40b is screwed is accommodated in the concave portion 33a of the connecting portion 33, and the side wall surface 34a of the fixing nut 34 is in contact with the inner wall surface 33b of the concave portion 33a. . For this reason, when the stud bolt 40 is rotated, the inner wall surface 33b of the recess 33a and the side wall surface 34a of the fixing nut 34 are in contact with each other in a direction perpendicular to the axial direction of the first screw portion 40b of the stud bolt 40. Touch.

  Therefore, when the first screw portion 40b is screwed into the fixing nut 34, it is preferable that the fixing nut 34 is rotated in the rotational direction of the stud bolt 40 as the stud bolt 40 rotates around the axis. Can be suppressed. Thereby, the stud bolt 40 can be easily assembled and the external terminal part 30, the current collection block 35, and the current collection member 31 can be easily fixed to the main body member 12. In the present embodiment, a restriction that restricts the rotation of the fixing nut 34 with the rotation of the stud bolt 40 from the recess 33a that becomes the first restricting part and the side wall surface 34a of the fixing nut 34 that becomes the second restricting part. The part is composed.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The stud bolt 40 includes a first screw portion 40b made of metal (iron) having higher strength than the external terminal portion 30 and the connection portion 36 (the current collecting member 31 and the connecting portion 33), and the first screw. The external terminal portion 30 is connected to one end side of the portion 40b, while the connecting portion 36 (connecting portion 33) is connected to the other end side, and the external terminal portion 30 and the connecting portion 36 are fixed to the wall portion 12b. Yes. For this reason, the strength of the stud bolt 40 that fixes the external terminal portion 30 and the connecting portion 36 to the case 11 can be improved. The conductive portion 32 extends along the axial direction of the first screw portion 40b and penetrates the wall portion 12b. The external terminal portion 30 is connected to one end side, and the connection portion 36 is connected to the other end side. 30 and the connection part 36 are electrically connected. The conductive portion 32 is made of the same metal as the external terminal portion 30 and the connection portion 36. Therefore, a conductive path between the external terminal portion 30 and the connection portion 36 is formed by the conductive portion 32 made of the same metal as the external terminal portion 30 and the connection portion 36, and the stud bolt 40 is temporarily connected to the external terminal portion 30 and the connection portion 36. Even if it is a case where it forms with the metal of the electrical conductivity lower than the part 36, it can suppress that an electrical resistance becomes high. Therefore, it is possible to suppress an increase in electrical resistance while improving the strength.

  (2) In the positive electrode terminal 52 and the negative electrode terminal 53, the current collecting member 31 electrically connected to the electrode assembly 25 has the top surface 31 c of the current collecting terminal holder 37 formed on the wall portion 12 b of the case 11. While being in contact with the plate portion 37a, it is in contact with the connecting portion 33 connected to the stud bolt 40 on the lower surface 31b which is the opposite surface to the upper surface 31c. The current collecting member 31 is sandwiched between the current collecting terminal holder 37 and the connecting portion 33 of the case 11. Therefore, it is possible to suppress an increase in electrical resistance at the contact portion between the current collecting member 31 and the connecting portion 33.

  (3) In the positive terminal 52 and the negative terminal 53, the stud bolt 40 is formed with a first screw portion 40b, while the fixing nut 34 is formed with a screw hole 34b. For this reason, the 1st screw part 40b and the connection part 33 can be easily connected by screwing the 1st screw part 40b in the screw hole 34b.

  (4) In the positive electrode terminal 52 and the negative electrode terminal 53, the fixing nut 34 is accommodated in the recess 33 a, thereby restricting the rotation of the fixing nut 34 with the rotation of the stud bolt 40. Therefore, the stud bolt 40 (first screw portion 40b) can be rotated, and the screw hole 34b of the fixing nut 34 and the first screw portion 40b can be easily screwed together.

  (5) In the positive electrode terminal 52 and the negative electrode terminal 53, the inner wall surface 33 b of the recess 33 a formed in the connecting portion 33 and the side wall surface 34 a of the fixing nut 34 are orthogonal to the axial direction of the first screw portion 40 b in the stud bolt 40. Abut in direction. Therefore, the rotation of the fixing nut 34 accompanying the rotation of the stud bolt 40 can be reliably controlled.

  (6) Further, in the positive electrode terminal 52 and the negative electrode terminal 53, the fixing nut 34 accompanying the rotation of the stud bolt 40 with a simple configuration is brought into contact with the inner wall surface 33b of the recess 33a and the side wall surface 34a of the fixing nut 34. Can be suitably controlled.

  (7) The secondary battery 10 includes a current collecting terminal holder 37 and an external terminal holder 38 made of an insulating material. For this reason, the connection part 36, the conductive part 32, and the external terminal part 30 can be insulated from the case 11.

  (8) In the positive electrode terminal 52 and the negative electrode terminal 53, the connecting portion 33 and the conductive portion 32 are integrally formed as a current collecting block 35. For this reason, while being able to form the electroconductive part 32 and the connection part 33 easily, an electrical resistance can be restrained low compared with the case where the electroconductive part 32 and the connection part 33 are formed in a different body.

(9) As the secondary battery 10, it is possible to suppress an increase in electrical resistance while improving the tensile strength in the connection structure between the connection portion 36 and the external terminal portion 30.
The embodiment is not limited to the above, and may be embodied as follows, for example.

  As shown in FIGS. 6 to 8, the electrode assembly 25 is a state in which the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 are formed in a long sheet shape (band shape) and the separator 23 is sandwiched therebetween. Thus, the positive electrode sheet 21 and the negative electrode sheet 22 may be wound in a spiral shape so that the positive electrode sheet 21 and the negative electrode sheet 22 form a layer (laminated structure).

  In this case, as shown in FIG. 7, in the positive electrode sheet 21, the length of the positive electrode sheet 21 indicated by the arrow Y5 is provided at one end portion (right end portion in this example) in the width direction (left-right direction) indicated by the arrow Y1. The non-application area | region 26b is formed so that it may extend along a direction, and the positive electrode lead 21a which protrudes to the outer side (right side) of the width direction is provided. On the other hand, in the negative electrode sheet 22, a non-application region 26 b is formed at the other end in the width direction (left end in this example) so as to extend along the length direction of the negative electrode sheet 22. A negative electrode lead 22a protruding outward (left side) is provided. As a result, a positive electrode current collector 28 in which the positive electrode lead 21 a forms a layer is formed at the right end (right side) of the electrode assembly 25. Further, a negative electrode current collector 29 in which the negative electrode lead 22 a forms a layer is formed at the left end (left side) of the electrode assembly 25.

  In this case, as shown in FIG. 8, each current collecting member 31 has a rectangular flat plate shape in a plan view, and a sandwiching portion 31 d sandwiched between the current collecting terminal holder 37 and the connecting portion 33, From the edge of the part 31d, a hanging part 31e having a rectangular flat plate shape in a side view hanging from an edge arranged on the outer side in the direction (left-right direction) in which the winding axis of the electrode assembly 25 extends, It is formed in a substantially inverted L shape when viewed from the front. A notch 31a is formed in the clamping part 31d.

  The drooping portion 31e in the positive electrode current collecting member 31 is inserted between the positive electrode current collecting portions 28 from the outer side (right side) in the left-right direction of the electrode assembly 25, and the positive electrode current collecting portions 31e The positive electrode lead 21a forming the portion 28 may be bonded so as to face each other. The same applies to the current collecting member 31 for the negative electrode.

  The conductive part 32 and the connecting part 33 may be formed separately. In this case, the current collecting member 31 may be formed integrally with the conductive portion 32 or the connecting portion 33. Further, the conductive portion 32 and the external terminal portion 30 may be integrally formed. Furthermore, the conductive portion 32 may be formed integrally with the first screw portion 40b by casting or the like.

The current collecting member 31 and the current collecting block 35 may be integrally formed.
(Circle) the electroconductive part 32 may comprise the rectangular tube shape and may be formed in the multiple or single column shape.

  A first screw portion 40b is formed instead of the screw hole 34b of the fixing nut 34, and the external terminal portion 30, the current collecting member 31, and the fixing nut 34 are screwed into the first screw portion 40b. The current collecting block 35 may be sandwiched and fixed to the main body member 12. In this other example, the fixing portion is constituted by the fixing nut 34 having the first screw portion 40b and the nut screwed to the first screw portion 40b, and forms a part of the fixing portion, and the first screw portion 40b The nut to be screwed faces the external terminal portion 30.

In place of the stud bolt 40, the external terminal portion 30, the current collecting member 31, and the current collecting block 35 may be sandwiched and fixed to the main body member 12 by rivets.
The main body member 12 may be formed in a bottomed cylindrical shape, and each external terminal portion 30 may be formed on the outer surface of the lid member 13 that covers the opening 12c of the main body member 12. In this case, the lid member 13 becomes a terminal wall.

  ○ By providing a protrusion on one of the fixing nut 34 and the connecting portion 33 and providing a hole to fit the protrusion on the other, the rotation of the fixing nut 34 with the rotation of the stud bolt 40 is restricted. May be.

  The metal forming the stud bolt 40 may be appropriately changed as long as it has a higher tensile strength than the metal forming the current collecting member 31, the current collecting block 35, and the external terminal portion 30. Further, the stud bolt 40 may be made of a metal having not only a tensile strength but also other mechanical strength such as yield strength and brittle strength.

The conductive part 32 that electrically connects the negative electrode current collector 29 and the external terminal part 30 for the negative electrode may be omitted. In this case, the stud bolt 40 may be formed of copper.
The external terminal portion 30, the conductive portion 32, and the connection portion 36 may be formed from a metal other than aluminum or copper.

  The stud bolt 40 may be formed from the same metal as the metal that forms the external terminal portion 30, the conductive portion 32, and the connection portion 36. Further, the stud bolt 40 may be formed of a metal having higher conductivity than the metal forming the external terminal portion 30, the conductive portion 32, and the connection portion 36. That is, the stud bolt 40 may be formed of a metal having a higher tensile strength (mechanical strength) than the metal forming the external terminal portion 30, the conductive portion 32, and the connection portion 36. The fixing nut 34 can be similarly changed.

The electrode assembly 25 may be laminated by bending the positive electrode sheet 21 and the negative electrode sheet 22 into a bellows shape with the separator 23 interposed therebetween.
The shape of the case 11 (main body member 12) may be formed in a columnar shape or an elliptical column shape that is flat in the left-right direction.

The present invention may be embodied as an electric double layer capacitor as a power storage device.
○ The secondary battery 10 of the above embodiment is mounted on a vehicle (for example, an industrial vehicle or a passenger vehicle), and is charged by a generator mounted on the vehicle, while the compressor for an air conditioner is supplied with electric power supplied from the secondary battery 10 Alternatively, an electric motor for driving the wheels or an electrical component such as a car navigation system may be driven. According to this, it is possible to suppress an increase in electrical resistance while improving the strength (mechanical strength) of the positive electrode terminal 52 and the negative electrode terminal 53 as the secondary battery 10. For this reason, while being able to suppress suitably that the positive electrode terminal 52 and the negative electrode terminal 53 are damaged by the vibration at the time of driving | running | working, the loss of the electric power accompanying charging / discharging can be reduced.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery (electric storage apparatus), 11 ... Case, 12b ... Wall part (terminal wall), 25 ... Electrode assembly, 30 ... External terminal part, 31 ... Current collecting member, 31b ... Lower surface (2nd contact surface) ), 31c ... Upper surface (first contact surface), 32 ... Conducting portion, 33 ... Connecting portion, 33a ... Recessed portion (regulating portion, first regulating portion), 33b ... Inner wall surface, 34 ... Fixing nut (fixing portion, shaft) (Connection part), 34a ... side wall surface (restriction part, second restriction part, outer wall surface), 34b ... screw hole (female screw part), 36 ... connection part, 37 ... current collecting terminal holder (insulating member), 40 ... stud Bolt (fixed part), 40a ... nut part, 40b ... first screw part (shaft part, male screw part).

Claims (9)

Case and
An electrode assembly housed in the case;
An external terminal part formed of metal formed outside the case and having an insertion hole;
The external terminal part is made of the same metal, and a connection part electrically connected to the electrode assembly inside the case;
A fixing portion for fixing the external terminal portion;
Electrically connecting the external terminal portion and the connection portion, and having a conductive portion having an insertion hole,
The fixed portion, the external terminal portion, and the connection portion are insulated from the wall of the case,
The fixed portion has a shaft portion made of a metal having higher strength than the external terminal portion and the connection portion,
The case has a terminal wall through which the shaft portion passes,
The shaft portion is inserted into the insertion hole of the external terminal portion, the external terminal portion is connected to one end side, while the connection portion is connected to the other end side, and the external terminal portion and the connection portion are Fixed to the terminal wall by the fixing portion;
The conductive portion penetrates the terminal wall,
The external terminal portion is connected to the one end side in surface contact, while the connection portion is connected to the other end side, and the external terminal portion and the connection portion are made of the same metal,
And extends along the axial direction of the shaft portion,
The shaft portion is inserted through the insertion hole of the conductive portion,
In the power storage device, the shaft portion has the same diameter as a portion inserted through the insertion hole of the external terminal portion and a portion inserted through the insertion hole of the conductive portion. Case and
An electrode assembly housed in the case;
An external terminal portion formed of metal formed outside the case;
The external terminal part is made of the same metal, and a connection part electrically connected to the electrode assembly inside the case;
A fixing portion for fixing the external terminal portion;
A conductive portion that electrically connects the external terminal portion and the connection portion;
The fixed portion, the external terminal portion, and the connection portion are insulated from the wall of the case,
The fixed portion has a shaft portion made of a metal having higher strength than the external terminal portion and the connection portion,
The case has a terminal wall through which the shaft portion passes,
The shaft portion has one end side connected to the external terminal portion and the other end side connected to the connection portion, and the external terminal portion and the connection portion are fixed to the terminal wall by the fixing portion. ,
The conductive portion penetrates the terminal wall,
The external terminal portion is connected to one end side while the connection portion is connected to the other end side, and the external terminal portion and the connection portion are made of the same metal,
And extends along the axial direction of the shaft portion,
The terminal wall has an insulating member disposed on the electrode assembly side,
The connection part includes a connection part connected to the shaft part inside the case, and a current collecting member formed separately from the connection part and electrically connected to the electrode assembly. ,
The current collecting member is formed with a first contact surface that contacts the insulating member, and a second contact surface that is opposite to the first contact surface and contacts the connecting portion.
The power storage device, wherein the current collecting member is sandwiched between the insulating member and the connecting portion. The terminal wall has an insulating member disposed on the electrode assembly side,
The connection part includes a connection part connected to the shaft part inside the case, and a current collecting member formed separately from the connection part and electrically connected to the electrode assembly. ,
The current collecting member is formed with a first contact surface that contacts the insulating member, and a second contact surface that is opposite to the first contact surface and contacts the connecting portion.
The power storage device according to claim 1 , wherein the current collecting member is sandwiched between the insulating member and the connecting portion . The fixed portion further includes a shaft coupling portion disposed on the opposite side of the coupling portion from the second contact surface side,
One of the shaft portion and the shaft coupling portion is formed with a male screw portion, while the other of the shaft portion and the shaft coupling portion is formed with a female screw portion, The power storage device according to claim 2 or 3 , wherein the male screw portion and the female screw portion are screwed together. The power storage device according to claim 4 , further comprising a restricting portion that restricts the shaft connecting portion from rotating as the shaft portion rotates. The restricting portion includes a first restricting portion formed in the connecting portion and a second restricting portion formed in the shaft connecting portion, and the first restricting portion and the second restricting portion are The power storage device according to claim 5 , wherein the rotation of the shaft coupling portion is restricted by contacting in a direction orthogonal to the axial direction of the shaft portion. The first restricting portion is a recess formed in the connecting portion;
The power storage device according to claim 6 , wherein the second restricting portion is an outer wall surface that is formed in the shaft coupling portion and contacts an inner wall surface of the recess to restrict rotation of the shaft coupling portion. Power storage device according to any one of claims 2-7, characterized in that it is formed integrally with the conductive portion and the connecting portion. Said power storage device, a power storage device according to any one of claims 1 to 8, which is a secondary battery.