JP2013134893A - Connection structure, secondary battery, and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure which allows for enhancement of volume energy density by reducing the area of an uncoated part, and to provide a secondary battery and a vehicle.SOLUTION: The connection structure electrically connects an electrode body 21 where a positive electrode sheet 24 formed by coating a metal foil 24a with an active material and a negative electrode sheet 25 are layered while sandwiching a sheet-like separator 23, with collector terminals 17, 18, respectively, by bonding. A non-coated region 27 not coated with the active material extends along at least one side of the positive electrode sheet 24 and negative electrode sheet 25. The positive electrode sheet 24 is bonded to the collector terminal 17 in the non-coated region 27, and the bonding region 35 of the non-coated region 27 and the collector terminal 17 extends in the extension direction of the non-coated region 27.

Description

  The present invention provides a connection structure for joining and electrically connecting an electrode body and a current collecting member, a secondary battery in which the electrode body and the current collecting member are connected by the connection structure, and the secondary battery. It relates to the mounted vehicle.

  Conventionally, lithium ion secondary batteries and nickel metal hydride secondary batteries are known as secondary batteries. For example, in a lithium ion secondary battery, a plurality of electrode sheets each having an active material layer formed on a metal sheet (aluminum foil or copper foil) are laminated or wound to form an electrode body in which the electrode sheet forms a layer. The electrode body is housed in a case (for example, Patent Document 1).

  In patent document 1, while providing the current collection member electrically connected with the uncoated part formed in the edge part of an electrode sheet, this current collection member is electrically connected with the electrode terminal provided so that it may protrude from a case (For example, Patent Document 1).

JP 2006-236790 A

  By the way, recently, there is a strong demand for improving the volume energy density and reducing the size or capacity of the secondary battery. Since the active material layer is not formed on the uncoated part of each electrode sheet in the secondary battery, it is considered that the volume energy density can be improved by reducing the area of the uncoated part. It is done.

  However, in Patent Document 1, there is no specific disclosure about how to set the joining region between the current collecting member and the uncoated part, and the volume energy is reduced by reducing the area of the uncoated part. It was desired to improve the density.

  This invention was made paying attention to the problem which exists in the said prior art, The objective is the connection structure which can make the area of an uncoated part small, and can improve a volume energy density, secondary It is to provide a battery and a vehicle.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a layered electrode body in which a positive electrode sheet in which an active material is applied to a metal sheet and a negative electrode sheet sandwich a sheet-like separator therebetween, A connection structure for joining and electrically connecting a current collecting member, wherein the positive electrode sheet and the negative electrode sheet each have an uncoated portion on which at least one active material is not applied on at least one side The positive electrode sheet and the negative electrode sheet are joined to the current collecting member in the uncoated part, and the joining region between the uncoated part and the current collecting member is: The gist is that it extends along the direction in which the uncoated portion extends.

  According to this, the uncoated part to which the active material is not apply | coated is each extended along the at least any one side at the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet are joined to and electrically connected to the current collecting member in the uncoated part, and the joint region between the uncoated part and the current collecting member extends from the uncoated part. It extends along the direction. For this reason, for example, the amount of protrusion of the uncoated portion in the positive electrode sheet and the negative electrode sheet is set to be small compared to the case where the joining region is provided so as to extend along the direction orthogonal to the extending direction of the uncoated portion. be able to. Accordingly, the volume energy density can be improved by reducing the area of the uncoated portion.

  Invention of Claim 2 is the connection structure of Claim 1, The said uncoated part and the said current collection member are joined by seam welding, The said joining area | region is the said uncoated part. The gist is that the shape extends continuously in the extending direction.

  According to this, the uncoated part and the current collecting member are joined by seam welding, and the joining region has a shape extending continuously in the extending direction of the uncoated part. For this reason, even if it sets the length of the width direction in a joining area | region small, the joining area of an uncoated part and a current collection member is ensured, and it can electrically connect reliably.

  The invention according to claim 3 is the connection structure according to claim 1 or 2, wherein the current collecting member has a plate-like member, and an outer peripheral end surface of the plate-like member is joined to the uncoated portion. In addition, the gist of the joining region extends along the outer peripheral end surface of the plate-like member.

  According to this, the outer peripheral end surface of the plate-shaped member in the current collecting member is joined to the uncoated portion. For this reason, the length of the width direction in a joining area | region can be set further narrowly, and the area of an uncoated part can be made small.

  The gist of the invention according to claim 4 is that, in the connection structure according to claim 3, the uncoated portion having a layer shape is joined to the outer peripheral end face. According to this, since the uncoated part which made the layer form is joined to the end surface of a plate-shaped member, it can manufacture simply compared with the structure joined individually.

  The gist of the invention described in claim 5 is that, in the secondary battery, the electrode body and the current collecting member are connected by the connection structure according to any one of claims 1 to 4. According to this, since the volume energy density can be improved by reducing the area of the uncoated portion, the secondary battery can be reduced in size and increased in capacity.

The gist of the invention described in claim 6 is that the secondary battery according to claim 5 is mounted in a vehicle.
According to this, since the volume energy density can be improved by reducing the area of the uncoated portion, the secondary battery can be reduced in size and increased in capacity. Therefore, for example, when the capacity of the secondary battery is increased, the amount of electric power (usage time) that can be used by one full charge in the vehicle can be improved. In addition, when the secondary battery is downsized, the degree of freedom of the location where the secondary battery is installed in the vehicle can be improved.

  According to the present invention, the volume energy density can be improved by reducing the area of the uncoated portion.

The perspective view which shows a lithium ion secondary battery typically. The disassembled perspective view which shows an electrode body typically. The front view which shows a lithium ion secondary battery typically. (A) is the left view which shows a lithium ion secondary battery typically, (b) is the sectional view on the AA line shown to (a). The perspective view which shows typically the lithium ion secondary battery in another embodiment.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, a lithium ion secondary battery (hereinafter simply referred to as “secondary battery”) 10 as a secondary battery mounted on a vehicle (for example, an industrial vehicle or a passenger vehicle) is generally flat. A case 11 having a cubic shape is provided. The case 11 is a flat plate assembled to the main body member 12 so as to cover (seal) the main body member 12 formed in a bottomed cylindrical shape (in this embodiment, a square cylindrical shape) and the opening 12a of the main body member 12. The lid member 13 is formed in a rectangular flat plate shape in the present embodiment. The main body member 12 and the lid member 13 are both made of metal (for example, stainless steel or aluminum). Hereinafter, for convenience of explanation, the longitudinal direction of the case 11 indicated by the arrow Y1 in FIG. 1 is indicated as the left-right direction, the short direction (thickness direction) of the case 11 indicated by the arrow Y2 is indicated as the front-rear direction, and the arrow Y3 The height direction of the case 11 to be shown is indicated as the vertical direction.

  The lid member 13 is provided with a positive electrode terminal 15 and a negative electrode terminal 16 having a cylindrical shape (substantially cylindrical shape) projecting upward from the upper surface of the lid member 13. Further, a base end (one end) of a current collecting terminal 17 as a current collecting member made of metal (for example, aluminum) and electrically connected to the positive electrode terminal 15 is fixed to the lower surface (inner surface) of the lid member 13. Yes. In addition, a base end (one end) of a current collecting terminal 18 as a current collecting member made of metal (for example, copper) and electrically connected to the negative electrode terminal 16 is fixed to the lower surface (inner surface) of the lid member 13. Yes. In the present embodiment, the positive electrode terminal 15, the negative electrode terminal 16, and the current collecting terminals 17 and 18 are in an insulated state from the case 11 (the main body member 12 and the lid member 13). The current collecting terminals 17 and 18 will be described in detail later.

  Further, the case 11 accommodates an electrode body 21 that forms a layer with a plurality of electrode sheets in which an active material layer is formed on a metal sheet (metal foil) with a separator interposed therebetween. As shown in FIG. 2, in the electrode body 21, a positive electrode sheet 24 as a positive electrode sheet having a long rectangular sheet shape and a long rectangular sheet shape with a sheet-like separator 23 sandwiched therebetween. The positive electrode sheet 24 and the negative electrode sheet 25 are formed in a layered structure (laminated structure) by winding the negative electrode sheet 25 as a negative electrode sheet in a spiral shape. The separator 23 is a rectangular porous sheet made of an insulating resin material (for example, polyethylene). In the present embodiment, the left-right direction indicated by the arrow Y1 is the direction in which the winding axis of the electrode body 21 (the positive electrode sheet 24 and the negative electrode sheet 25) extends.

Here, the positive electrode sheet 24 and the negative electrode sheet 25 will be described in detail.
The positive electrode sheet 24 includes a metal foil 24a (for example, aluminum foil) as a metal sheet having a rectangular (substantially rectangular) long sheet shape, while the negative electrode sheet 25 is a substantially rectangular long sheet shape. The metal foil 25a (for example, copper foil) is provided as a metal sheet.

  On both surfaces of the metal foil 24a, the metal foil 24a has a predetermined width from one end (side) E1 in the width direction indicated by the arrow Y1 (left side in the present embodiment) over the entire length direction indicated by the arrow Y4. Except for the set non-coated area 27 as an uncoated part, an active material for a positive electrode is applied to the entire surface to form an active material layer 26. Similarly, on both surfaces of the metal foil 25a, a non-application region set with a predetermined width from the other end (side) E2 in the width direction (right side in the present embodiment) across the entire length direction of the metal foil 25a. Except for 27, an active material for a negative electrode is applied to the entire surface, and an active material layer 26 is formed.

  For this reason, in the positive electrode sheet 24 and the negative electrode sheet 25, the non-application area | region 27 is each provided so that it may extend along one side of the length direction in each metal foil 24a, 25a. In the present embodiment, the non-application region 27 of the positive electrode sheet 24 becomes the positive electrode lead 24b extending along the end E1 of the positive electrode sheet 24, and the non-application region 27 of the negative electrode sheet 25 is the negative electrode sheet 25. The negative electrode lead 25b is extended along the end E2. In the present embodiment, the length directions of the positive electrode sheet 24 and the negative electrode sheet 25 are the extending direction (extending direction) of the non-application region 27.

  The electrode body 21 protrudes in one direction (leftward in the present embodiment) in which the positive electrode lead 24b of the positive electrode sheet 24 extends, and the negative electrode lead 25b of the negative electrode sheet 25 corresponds to the winding axis. The positive electrode sheet 24 and the negative electrode sheet 25 are overlapped via a separator 23 so as to protrude to the other side in the extending direction (rightward in the present embodiment), and are wound. The electrode body 21 is housed in the case 11 in a state in which the extending direction of the winding axis coincides with the longitudinal direction of the case 11, and the positive electrode lead 24b is disposed on the left hand side in the case 11. The negative electrode lead 25b is arranged on the right hand.

  For this reason, as shown in FIG. 1, the positive electrode connection part which makes | forms the layered structure in the direction orthogonal to the direction (left-right direction) where the positive electrode lead 24b of the positive electrode sheet 24 is extended in the left end part of the electrode body 21 28 is formed. More specifically, in the present embodiment, at the left end portion of the electrode body 21, the positive electrode lead 24b of the positive electrode sheet 24 is divided into two in the front-rear direction, so that two positive electrode connection portions 28 are arranged in the front-rear direction. Is formed. That is, in each positive electrode connection portion 28, the non-application region 27 (metal foil 24 a) of the positive electrode sheet 24 has a layer shape (laminated structure) in a state where the separator 23 is not sandwiched therebetween.

  On the other hand, a negative electrode connection portion 29 that is layered in a direction orthogonal to the direction in which the negative electrode lead 25b of the negative electrode sheet 25 extends in the right end portion of the electrode body 21 is formed. More specifically, in the present embodiment, at the right end portion of the electrode body 21, the negative electrode lead 25b of the negative electrode sheet 25 is divided into two in the front-rear direction, so that two negative electrode connection portions 29 are arranged in the front-rear direction. Is formed. That is, each negative electrode connection portion 29 has a layered structure (laminated structure) in a state where the non-application region 27 (metal foil 25a) of the negative electrode sheet 25 does not sandwich the separator 23 therebetween. Therefore, in the present embodiment, a plurality of connection portions (a positive electrode connection portion 28 and a negative electrode connection portion 29) are formed at each end portion of the electrode body 21.

  The positive electrode connection portion 28 (positive electrode lead 24b) is electrically connected to the tip end portion (one end) of the current collecting terminal 17, while the negative electrode connection portion 29 (negative electrode lead 25b) is the same as described above. The current collector terminal 18 is electrically connected to the tip (one end). The case 11 is filled with a liquid or gel electrolyte (not shown).

  Hereinafter, each positive electrode connecting portion 28 and the current collecting terminal 17 of the electrode body 21 and each negative electrode connecting portion 29 and the current collecting terminal 18 which are characteristic in the secondary battery 10 of the present embodiment are joined and electrically connected. The connection structure (joining structure) for this will be described in detail with reference to FIGS. In the present embodiment, the current collecting terminal 17 and the current collecting terminal 18 are symmetrical in shape. Further, the connection structure between the current collecting terminal 17 and the positive electrode sheet 24 (positive electrode connecting portion 28) and the connection structure between the current collecting terminal 18 and the negative electrode sheet 25 (negative electrode connecting portion 29) are symmetrical. . Therefore, in the following description, only the configuration of the current collector terminal 17 and the connection structure between the current collector terminal 17 and the positive electrode sheet 24 will be described in detail, and the configuration of the current collector terminal 18 and the current collector terminal 18 and About the connection structure with the electrode sheet 25, the description is simplified by attaching | subjecting the same code | symbol.

  As shown in FIGS. 3 and 4, the current collecting terminal 17 is formed by bending a substantially rectangular flat plate made of a metal (aluminum in this embodiment) as a conductive material, for example, by pressing. The current collecting terminal 17 has a rectangular flat plate shape extending in the left-right direction, and a connecting portion 30 that is electrically connected to the positive electrode terminal 15, and a rectangular flat plate shape that is suspended downward from the outer end in the left-right direction of the connecting portion 30. A hanging portion 31 is provided. And the current collection terminal 17 is provided with the insertion part 32 as a plate-shaped member (joining part) arrange | positioned so that it may be inserted between the two positive electrode connection parts 28 in a row by the lower end of the drooping part 31. Yes.

  As shown in FIGS. 3 and 4A, the insertion portion 32 has a rectangular shape (substantially rectangular shape) in a side view extending along a direction in which the positive electrode connection portion 28 (positive electrode lead 24b) extends (the vertical direction in this case). It has a flat plate shape and is arranged in a state in which the thickness direction thereof coincides with the direction (left-right direction) in which the winding axis of the electrode body 21 extends. For this reason, as shown in FIG. 4B, the insertion portion 32 has a front end surface 32a and a rear end surface 32b as outer peripheral end surfaces arranged in a direction orthogonal to the thickness direction, respectively, facing the inner surface of the positive electrode connection portion 28. As shown, each positive electrode connection portion 28 is inserted.

  Further, as shown in FIGS. 3 and 4B, the insertion portion 32 is inserted between the positive electrode connection portions 28 by the thickness of the insertion portion 32, and is disposed on the outer side in the left-right direction of the electrode body 21. The left side surface of the insertion portion 32 and the tip end portion of the positive electrode connection portion 28 are flush with each other when viewed from the front.

  And as shown in FIG. 3, each positive electrode connection part 28 in the electrode body 21 and the insertion part 32 in the current collection terminal 17 are joined and electrically connected in the joining area | region 35 (it shows with light ink). . More specifically, the positive electrode connection portion 28 disposed on the front side of the insertion portion 32 is arranged on the front end surface 32a of the insertion portion 32 so as to gather the positive electrode leads 24b that are layered in the positive electrode connection portion 28. Are joined. Similarly, the positive electrode connection portion 28 disposed on the rear side of the insertion portion 32 is joined to the rear end surface 32b of the insertion portion 32 so that the positive electrode leads 24b that are layered in the positive electrode connection portion 28 gather together. Has been.

  And in this embodiment, the insertion part 32 and each positive electrode connection part 28 are continuously joined over the whole joining area | region 35 by seam welding. The joining region 35 is provided so as to extend along the direction in which the end E1 of the positive electrode sheet 24 extends and the extending direction (vertical direction in the present embodiment) of the positive electrode connecting portion 28 (positive electrode lead 24b). .

  Seam welding is a type of resistance welding, in which a current is passed between a roller-type electrode disposed so as to sandwich the positive electrode connection portion 28 between the insertion portion 32 and the insertion portion 32, and the positive electrode is applied by the roller-type electrode. In this welding method, the positive electrode connection portion 28 and the current collecting terminal 17 are continuously welded by rolling the connection portion 28 while applying pressure. For this reason, the bonding region 35 of the present embodiment is a concave portion that is slightly recessed from the surface of the positive electrode connection portion 28. Moreover, the current collection terminal 18 of this embodiment is formed from the metal (copper in this embodiment) as an electroconductive material.

  Thus, in the present embodiment, the positive electrode sheet 24 (positive electrode connection portion 28) is bonded to the current collecting terminal 17 in the non-application area 27 and the bonding area between the non-application area 27 and the current collection terminal 17 is. 35 extends along the direction in which the non-application area 27 extends. Moreover, the non-application area | region 27 and the current collection terminal 17 are joined by seam welding, and the joining area | region 35 has the shape extended continuously in the direction where the non-application area | region 27 is extended. Furthermore, in the present embodiment, the front end surface 32a and the rear end surface 32b, which are outer peripheral end surfaces of the insertion portion 32, are joined to the positive electrode connection portion 28 (non-application region 27), respectively, and the joining region 35 is connected to the insertion portion 32. Each extends along the front end face 32a and the rear end face 32b. Further, the outermost portion (left end portion in the present embodiment) in the left-right direction of the positive electrode connecting portion 28 (non-application region 27) is joined to the front end surface 32a and the rear end surface 32b of the insertion portion 32. The same applies to the junction between the current collecting terminal 18 and the negative electrode connecting portion 29 (non-application region 27).

Next, the effect | action of the secondary battery 10 (connection structure of the electrode body 21 and the current collection terminals 17 and 18) comprised as mentioned above is demonstrated.
In the present embodiment, the current collecting terminal 17 and the positive electrode connecting portion 28, and the current collecting terminal 18 and the negative electrode connecting portion 29 are along the direction in which the positive electrode lead 24 b and the negative electrode lead 25 b extend (vertical direction in the present embodiment). It joins in the joining area | region 35 provided so that it might extend. Therefore, in the present embodiment, the length (width) in the left-right direction of the positive electrode lead 24b (non-application region 27) of the positive electrode sheet 24 can be reduced, and the negative electrode lead 25b ( The length (width) in the left-right direction in the non-application area 27) can be reduced. Therefore, for example, compared with the case where the bonding region 35 is provided so as to extend along the direction (left-right direction) orthogonal to the direction in which the positive electrode lead 24 b and the negative electrode lead 25 b extend, the positive electrode at the end of the electrode body 21. The protruding amount of the lead 24b and the negative electrode lead 25b can be set small. For this reason, the area of the positive electrode lead 24b and the negative electrode lead 25b (non-application region 27) can be reduced and the size can be reduced.

  In particular, the positive electrode lead 24 b and the negative electrode lead 25 b are joined to the front end surface 32 a and the rear end surface 32 b arranged in the direction intersecting the thickness direction (left-right direction) in the insertion portion 32, that is, the outer peripheral end surface of the insertion portion 32. Is done. For this reason, the length (width) in the left-right direction orthogonal to the direction in which the bonding region 35 extends is reduced, and the protruding amounts of the positive electrode lead 24b and the negative electrode lead 25b (non-application region 27) at the end of the electrode body 21 are reduced. It can be set suitably small.

  In the secondary battery 10 of the present embodiment, the active material layer 26 is formed in a larger area by reducing the areas of the positive electrode lead 24b and the negative electrode lead 25b (non-application region 27), thereby increasing the capacity. Can be achieved. Further, in the secondary battery 10 of the present embodiment, the length of the case 11 in the left-right direction is reduced by the amount that the areas of the positive electrode lead 24b and the negative electrode lead 25b (non-application region 27) are reduced. The secondary battery 10 can be reduced in size.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) The non-application area | region 27 to which the active material is not apply | coated is each along the edge part E1 used as one side in the positive electrode sheet 24, and the edge part E2 used as one side in the negative electrode sheet 25. It is extended. The positive electrode sheet 24 is joined to and electrically connected to the current collecting terminal 17 at the positive electrode lead 24 b which is the non-application area 27, and a joining area 35 between the positive electrode lead 24 b and the current collecting terminal 17. Extends along the direction in which the positive electrode lead 24b extends. The same applies to the joining of the negative electrode sheet 25 (negative electrode lead 25 b) and the current collecting terminal 18. For this reason, for example, compared with the case where the bonding region 35 is provided so as to extend along the direction orthogonal to the extending direction of the positive electrode lead 24 b and the negative electrode lead 25 b, the non-contact in the positive electrode sheet 24 and the negative electrode sheet 25 is not. The protrusion amount of the application region 27 can be set small. Accordingly, the volume energy density can be improved by reducing the area of the non-application region 27.

  (2) The positive electrode lead 24b (non-application region 27) of the positive electrode sheet 24 and the current collecting terminal 17 are joined by seam welding, and the joining region 35 extends continuously in the direction in which the positive electrode lead 24b extends. It has a shape. For this reason, even if the length (width) in the direction orthogonal to the direction in which the bonding region 35 extends is set small, the bonding area between the positive electrode lead 24b (positive electrode connection portion 28) and the current collecting terminal 17 is ensured. Can be electrically joined. The same applies to the joining of the negative electrode sheet 25 (negative electrode lead 25 b) and the current collecting terminal 18.

  (3) The positive electrode lead 24 b of the positive electrode sheet 24 is joined to the outer peripheral end surfaces (the front end surface 32 a and the rear end surface 32 b) in the insertion portion 32 of the current collecting terminal 17. For this reason, the length (length in the width direction) in the direction orthogonal to the direction in which the bonding region 35 extends can be set to be narrower, and the area of the positive electrode lead 24b (non-application region 27) can be reduced. The same applies to the joining of the negative electrode sheet 25 (negative electrode lead 25 b) and the current collecting terminal 18.

  (4) The positive electrode lead 24b is joined to the outer peripheral end surfaces (front end surface 32a and rear end surface 32b) of the insertion portion 32 in a layered state. For this reason, it is possible to collectively join the layered positive electrode leads 24b by one seam welding, and it can be easily manufactured as compared with the configuration in which the positive electrode leads 24b are individually joined. . The same applies to the joining of the negative electrode sheet 25 (negative electrode lead 25 b) and the current collecting terminal 18.

  (5) Moreover, since the positive electrode lead 24b (non-application area | region 27) can be reduced in size and a volume energy density can be improved, size reduction and high capacity | capacitance as the secondary battery 10 can be achieved.

  (6) The insertion portion 32 is inserted between the positive electrode connection portions 28 by the thickness of the insertion portion 32, and the left side surface of the insertion portion 32 and the left end portion of the positive electrode connection portion 28 are flush with each other in a front view. Has been. For this reason, the protrusion amount of the positive electrode lead 24b (non-application region 27) from the electrode body 21 can be further reduced. For example, when the left side surface of the insertion portion 32 protrudes outward in the left-right direction from the left end portion of the positive electrode connection portion 28, an installation space for the insertion portion 32 (the current collecting terminal 17) is required by the amount that the insertion portion 32 protrudes. become. On the other hand, when the left side surface of the insertion portion 32 is disposed on the inner side in the left-right direction than the left end portion of the positive electrode connection portion 28, the positive electrode connection portion 28 protrudes outward in the left-right direction from the left side surface of the insertion portion 32. Only waste occurs. The same applies to the joining of the negative electrode sheet 25 (negative electrode lead 25 b) and the current collecting terminal 18.

The embodiment is not limited as described above, and may be embodied as follows, for example.
As shown in FIG. 5, the electrode body 21 includes a positive electrode sheet 24 having a rectangular sheet shape and a negative electrode sheet 25 having a rectangular sheet shape with a separator 23 interposed therebetween (intervened). In the state), they may be laminated in the front-rear direction (thickness direction of the positive electrode sheet 24 and the negative electrode sheet 25). In addition, illustration of case 11 is abbreviate | omitted in FIG. In FIG. 5, the positive electrode lead 24b and the negative electrode lead 25b are illustrated in a simplified manner so as to be located on the same plane. Are arranged alternately.

  In this case, on both surfaces of each metal foil 24a, 25a, except for the non-application region 27 set with a predetermined width from the end E3 as one side on the entire width in the left-right direction of each metal foil 24a, 25a, An active material is applied to the entire surface to form an active material layer 26. Further, the upper left end portion of the metal foil 24a in the positive electrode sheet 24 is provided so as to extend the rectangular positive electrode lead 24b upward, while the upper right end portion of the metal foil 25a in each negative electrode sheet 25 is provided. Is provided so as to extend a rectangular negative electrode lead 25b upward. The positive electrode lead 24b and the negative electrode lead 25b are formed by punching the non-coating region 27 extending along the end portion E3 (one side). Each electrode lead 24b, 25b is formed so as to extend along the direction (left-right direction) in which the end E3 extends. As a result, a positive electrode connection portion 28 is formed at the upper left end portion of the electrode body 21, and a negative electrode connection portion 29 is formed at the upper right end portion of the electrode body 21.

  And in the current collection terminal 17, the insertion part 32 is formed in a rectangular flat plate shape in plan view extending along the extending direction of the positive electrode connection part 28 (each positive electrode lead 24b), and the outer peripheral end face (front end face 32a and Each positive electrode connection portion 28 is seam welded to the rear end face 32b). In this case, the bonding region 35 is provided so as to extend along the direction in which each positive electrode lead 24b (non-application region 27) extends (in this example, the left-right direction). The same applies to the joining of each negative electrode sheet 25 (negative electrode lead 25 b) and the current collecting terminal 18. Even if comprised in this way, the protrusion amount of the positive electrode lead 24b in the electrode body 21 and the negative electrode lead 25b (non-application | coating area | region 27) can be made small.

  The joining of the current collecting terminal 17 and the positive electrode connecting portion 28 (positive electrode lead 24b) and the joining of the current collecting terminal 18 and the negative electrode connecting portion 29 (negative electrode lead 25b) are performed by ultrasonic bonding or spot welding. , Each may be electrically connected.

  The current collecting terminal 17 and the positive electrode connecting portion 28 (positive electrode lead 24 b) may not be continuously joined in the joining region 35. For example, the spot-like welded portions may be joined so as to be intermittently arranged. That is, the joining region 35 only needs to extend along the extending direction of the non-application region 27 in the positive electrode sheet 24 and the negative electrode sheet 25. The same applies to the junction between the current collecting terminal 18 and the negative electrode connecting portion 29.

  O The shape of the current collecting terminal 17 may be changed as appropriate. For example, the insertion portion 32 may be provided with wall portions extending from both end portions in the front-rear direction of the insertion portion 32 toward the outer side in the left-right direction, and the positive electrode connection portion 28 may be joined to the front surface and the rear surface of the wall portion. Good. The same applies to the junction between the current collecting terminal 18 and the negative electrode connecting portion 29.

  In the insertion part 32, the outer side surface in the left-right direction may not be flush with the positive electrode connection part 28. For example, the left side surface of the insertion portion 32 protrudes outward in the left-right direction from the left end portion of the positive electrode connection portion 28, or the left side surface of the insertion portion 32 is disposed inward in the left-right direction from the left end portion of the positive electrode connection portion 28. May be. The same applies to the junction between the current collecting terminal 18 and the negative electrode connecting portion 29.

The shape of the positive electrode lead 24b (positive electrode connection portion 28) and the negative electrode lead 25b (negative electrode connection portion 29) may be changed as appropriate.
The number of the positive electrode connection portions 28 and the negative electrode connection portions 29 may be changed as appropriate. For example, each electrode lead 24b, 25b may be divided into four to form four positive electrode connecting portions 28 and negative electrode connecting portions 29, respectively. In this case, each of the current collecting terminals 17 and 18 may be provided with two insertion portions 32, and the insertion portions 32 may be joined so as to be sandwiched between the positive electrode connection portion 28 and the negative electrode connection portion 29.

(Circle) you may change suitably the number of the positive electrode sheet 24 which comprises the electrode body 21, and the negative electrode sheet 25. FIG.
The electrode body 21 may be laminated by bending the electrode sheets 24 and 25 into a bellows shape with the separator 23 interposed therebetween.

  The electrode body 21 may be accommodated in the case 11 in a state where the winding axis line coincides with the height direction (vertical direction) of the case 11. In this case, the positive electrode connection portion 28 and the negative electrode connection portion 29 may be formed at the upper end portion of the electrode body 21.

The shape of the case 11 may be formed in a columnar shape or an elliptical column shape that is flat in the left-right direction.
The non-application region 27 may be formed along a plurality of ends (sides) in the positive electrode sheet 24 and the negative electrode sheet 25.

The secondary battery 10 may be embodied as a nickel hydride secondary battery.
○ 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. Accordingly, the secondary battery 10 can be reduced in size and capacity. Therefore, for example, when the capacity of the secondary battery 10 is increased, it is possible to improve the amount of electric power that can be used in one full charge in the vehicle. In particular, when the electric motor is driven by electric power supplied from the secondary battery 10, the total travel distance that can be traveled by one full charge in the vehicle can be increased. Further, when the secondary battery 10 is reduced in size, the degree of freedom of the installation location of the secondary battery 10 in the vehicle can be improved.

  E1 to E3 ... end (side), 10 ... lithium ion secondary battery (secondary battery), 17, 18 ... current collecting terminal (current collecting member), 21 ... electrode body, 23 ... separator, 24 ... positive electrode sheet (Positive electrode sheet), 24a ... metal foil (metal sheet), 24b ... positive electrode lead, 25 ... negative electrode sheet (negative electrode sheet), 25a ... metal foil (metal sheet), 25b ... negative electrode lead, 26 ... active material layer , 27 ... non-application area (uncoated part), 32 ... insertion part (plate-like member), 32a ... front end face (outer end face), 32b ... rear end face (outer end face), 35 ... joining area.

Claims (6)

Connection for joining and electrically connecting a current collector and a layered electrode body with a sheet-like separator sandwiched between a positive electrode sheet and a negative electrode sheet coated with an active material on a metal sheet Structure,
The positive electrode sheet and the negative electrode sheet are each provided with an uncoated portion not coated with an active material extending along at least one side,
The positive electrode sheet and the negative electrode sheet are bonded to the current collecting member in the uncoated portion, and a bonding region between the uncoated portion and the current collecting member is a direction in which the uncoated portion extends. A connection structure characterized by extending along the line.   The uncoated portion and the current collecting member are joined by seam welding, and the joining region has a shape extending continuously in a direction in which the uncoated portion extends. Item 2. The connection structure according to Item 1. The current collecting member has a plate-like member,
While the outer peripheral end face of the plate-like member is joined to the uncoated part,
The connection structure according to claim 2, wherein the joining region extends along an outer peripheral end surface of the plate-like member.   The connection structure according to claim 3, wherein the uncoated portion having a layer shape is joined to the outer peripheral end surface.   A secondary battery, wherein the electrode body and the current collecting member are connected by the connection structure according to claim 1.   A vehicle comprising the secondary battery according to claim 5.