JP2013161758A - Connection structure, power storage device, and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure capable of suppressing heat generation accompanying electric power supply, a power storage device, and a vehicle.SOLUTION: A connection structure includes an electrode body 21 layered with a separator 22 sandwiched between a positive electrode sheet 23a and a negative electrode sheet 23b each having a metal foil 24a coated with an active material, and a current collecting terminal 30. The positive electrode sheet 23a and the negative electrode sheet 23b each have a non-coating region 25 (electrode lead 27) which is not coated with the active material. The current collecting terminal 30 has a main body part 30a electrically connected to a positive electrode terminal 15 and connection parts 35a to 35c electrically connected to the non-coating region 25. The main body part 30a has a reduction part 32 decreasing in the sectional area obtained by cutting with a plane orthogonal to a direction in which one side having the non-coating region 25 formed extends, from a base end 30b to a tip end 30c at positions where the connection parts 35a to 35c are provided, and is electrically connected to the positive electrode terminal 15 at a position of the reduction part 32 on the side of the base end 30b.

Description

  The present invention relates to a connection structure including an electrode body and a current collector, a power storage device in which the electrode body and the current collector are connected by this connection structure, and a vehicle equipped with the power storage device.

  Conventionally, lithium ion secondary batteries and nickel metal hydride secondary batteries are well known as power storage devices. For example, in a lithium ion secondary battery, an electrode body (positive electrode sheet and negative electrode sheet) in which an active material is applied to at least one surface of a metal sheet is layered, and an electrolyte salt (lithium salt) is dissolved. The nonaqueous electrolyte is housed in a case (battery tank) (for example, Patent Document 1).

  In the secondary battery of Patent Document 1, in the electrode body, an uncoated portion (electrode lead) that is not coated with an active material in the electrode sheet is connected to a connection portion formed on a current collecting member (current collecting terminal). On the other hand, the electrode body and the external terminal are electrically connected by connecting the current collecting member to the external terminal. And in patent document 1, the connection part is formed along the direction where the edge | side (edge part) in which the uncoated part was formed is extended.

JP 2003-249423 A

  However, in the current collecting member of Patent Document 1, at the position where the connection portion is provided, the cross-sectional area cut by a plane orthogonal to the extending direction of the side (edge) where the uncoated portion is formed is formed constant. Yes. For this reason, in the secondary battery of Patent Document 1, heat generation (Joule heat generation) increases as the current flowing through the current collection member (current collection terminal) increases as it approaches the connection position with the external terminal. There is a risk of it.

  This invention was made paying attention to the problem which exists in the said prior art, The objective is to provide the connection structure which can suppress the heat_generation | fever accompanying energization, a secondary battery, and a vehicle. is there.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a state in which a sheet-like separator is sandwiched between a positive electrode sheet and a negative electrode sheet in which an active material is applied to at least one surface of a metal sheet. And a current collecting member electrically connected to the electrode body and an external terminal, wherein an active material is applied to each of the positive electrode sheet and the negative electrode sheet. An uncoated portion that is not formed is formed on at least one side, and the current collecting member is electrically connected to the external terminal, and the uncoated portion is provided in the body portion. A plurality of connecting portions arranged side by side in the extending direction of the one side, and the main body portion is a base end that is one of the end portions in the extending direction of the one side And the tip which is the other end In addition, the cross-sectional area cut by a plane orthogonal to the extending direction of the one side at a position where the connection portion is provided has a reduction portion that decreases from the base end portion toward the tip end portion. The gist of the invention is that it is electrically connected to the external terminal at a position on the base end side or a position on the base end side with respect to the reduced portion in the main body.

  According to this, the main body portion of the current collecting member has one side where the uncoated portion is formed at a position where the uncoated portion to which the active material is not applied is electrically connected. The cross-sectional area cut | disconnected by the surface orthogonal to the extending direction of has a reduced part which becomes small toward a front-end | tip part from a base end part. And the current collection member is electrically connected with the external terminal in the position of the base end part side in the reduction | decrease part of a current collection member, or the position of the base end part side rather than the reduction | decrease part in a main-body part. For this reason, the electrical resistance (resistance value) at the position where the connecting portion is provided in the current collecting member (main body portion) becomes smaller as the position becomes closer to the connecting position between the current collecting member and the external terminal. Therefore, heat generation due to energization can be suppressed.

  According to a second aspect of the present invention, in the connection structure according to the first aspect, the connection portion is formed to extend from a portion of the main body portion that is disposed on the electrode body side, and the extension of the connection portion. The gist is that the cross-sectional area cut along the plane orthogonal to the outgoing direction becomes smaller toward the end of the connecting portion on the tip side.

  According to this, the cross-sectional area cut | disconnected by the surface orthogonal to the extension direction of the said connection part becomes small toward the edge part of the front end side of a connection part. For this reason, a connection part can be easily inserted between an uncoated part and an uncoated part, and a connection part and an uncoated part can be connected.

  The invention according to claim 3 is the connection structure according to claim 1 or 2, wherein the connection portion is connected to the uncoated portion so as to sandwich the uncoated portion from both sides. The gist.

According to this, since the connecting portion is connected so as to sandwich the uncoated portion, the electrical resistance (resistance value) at the connecting portion between the connecting portion and the uncoated portion can be reduced.
The invention according to claim 4 is the connection structure according to any one of claims 1 to 3, wherein in the electrode body, the positive electrode sheet and the negative electrode are wound by winding the positive electrode sheet and the negative electrode sheet. The gist is that the sheet has a layered shape, and the uncoated portions are formed at both ends of the electrode body in the direction in which the winding axis extends.

  According to this, an electrode body can be easily formed by winding a positive electrode sheet and a negative electrode sheet. Even in such an electrode body, the electrical resistance (resistance value) at the position where the connecting portion is provided in the current collecting member is made smaller as it is closer to the connecting position between the current collecting member and the external terminal, The heat generation associated with can be suppressed.

  According to a fifth aspect of the present invention, in the power storage device, the electrode body and the external terminal are electrically connected via the current collecting member by the connection structure according to any one of the first to fourth aspects. The summary is as follows. According to this, it can control that a current collection member generates heat with energization. For this reason, it can suppress having a bad influence on the performance as an electrical storage apparatus by the heat_generation | fever in a current collection member.

  The gist of the invention described in claim 6 is that the power storage device according to claim 5 is mounted in a vehicle. According to this, it can suppress that the performance as an electrical storage apparatus is adversely affected by the heat_generation | fever in a current collection member. Therefore, it is possible to suppress the replacement cycle of the power storage device from being shortened.

  According to the present invention, heat generation due to energization can be suppressed.

Sectional drawing which shows a secondary battery typically. The disassembled perspective view which shows an electrode body typically. The schematic perspective view for demonstrating the connection structure of a current collection terminal and an electrode lead. The perspective view which shows typically the current collection terminal at the time of seeing from the downward direction. The schematic perspective view for demonstrating the connection structure of a current collection terminal and an electrode lead. Sectional drawing which shows typically the secondary battery in 2nd Embodiment. The disassembled perspective view which shows typically the electrode body in 2nd Embodiment. The perspective view which shows typically the current collection terminal in 2nd Embodiment. The model left view for demonstrating the connection structure of the current collection terminal and electrode lead in 2nd Embodiment. The perspective view which shows typically the current collection terminal in another embodiment. The perspective view which shows typically the current collection terminal in another embodiment.

(First embodiment)
A first embodiment of the present invention will be described below 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 has a flat plate shape (this embodiment) assembled to the main body member 12 so as to seal the main body member 12 formed in a bottomed cylindrical shape (square tube shape in the present embodiment) and the opening 12a of the main body member 12. It is formed from a lid member 13 having a rectangular flat plate shape. 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 in FIG. This is indicated as the front-rear direction. In FIG. 1, the direction perpendicular to the paper surface is the front-rear direction.

  On the outer surface (upper surface) of the lid member 13, a positive electrode terminal 15 as an external terminal (electrode terminal) having a cylindrical shape (substantially cylindrical shape) and a negative electrode terminal 16 as an external terminal (electrode terminal) are provided so as to protrude. It has been. In the secondary battery 10 of the present embodiment, charging and discharging are performed via the positive terminal 15 and the negative terminal 16. The positive terminal 15 and the negative terminal 16 are insulated from the case 11 (the main body member 12 and the lid member 13).

  In addition, the case 11 accommodates (contains) an electrode body 21 having a rectangular parallelepiped shape (substantially rectangular parallelepiped shape) that is flat in the left-right direction. In the electrode body 21, a sheet-like base material having conductivity is used. A positive electrode sheet 23 a and a negative electrode sheet 23 b formed by applying an active material are layered with a separator (diaphragm) 22 interposed therebetween. The electrode body 21 is housed in the case 11 in a state of being covered with an insulating bag 11a made of an insulating material. In the case 11, for example, a lithium ion secondary battery or a nickel hydride secondary battery is used. Further, an electrolyte corresponding to the type of the secondary battery 10 is filled.

  As shown in FIG. 2, the positive electrode sheet 23a and the negative electrode sheet 23b include a metal foil 24a as a metal sheet as the base material having a rectangular sheet shape. The metal foil 24a 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 24a is different between the positive electrode sheet 23a and the negative electrode sheet 23b.

  On both surfaces (front surface and rear surface) of each metal foil 24a, there is an uncoated region 25 as an uncoated portion set at a constant width from the upper edge 24b as one side of each metal foil 24a over the entire width in the left-right direction. Except for this, an active material is applied to the entire surface, and an active material layer 26 is formed. That is, the non-application area | region 25 is extended along the upper edge part 24b of each metal foil 24a. In the present embodiment, the left-right direction indicated by the arrow Y1 is the direction in which the upper edge portion 24b extends. In addition, the active material according to the kind of secondary battery 10 is apply | coated to the metal foil 24a. The active material applied to the metal foil 24a is different between the positive electrode sheet 23a and the negative electrode sheet 23b.

  Further, by punching out the non-application region 25 of the positive electrode sheet 23a and the negative electrode sheet 23b, a positive electrode lead 27 having a rectangular shape (substantially rectangular shape) is formed on the upper left end of the positive electrode sheet 23a (on the lid member 13 side). ), And a negative electrode lead 27 having a rectangular shape (substantially rectangular shape) is formed upwardly extending (extending) at the upper right end of the negative electrode sheet 23b. Has been. Therefore, the active material layer 26 is not formed on the surfaces of the positive electrode lead 27 and the negative electrode lead 27 of this embodiment, and forms a part of the non-application region 25. The separator 22 is made of an insulating resin material and is a rectangular porous sheet having an extremely fine pore structure.

  The electrode body 21 is formed by laminating a positive electrode sheet 23a and a negative electrode sheet 23b in the front-rear direction (thickness direction) with a separator 22 interposed therebetween. More specifically, the positive electrode sheet 23a and the negative electrode sheet 23b are alternately arranged in the order of... → positive electrode sheet 23a.fwdarw.negative electrode sheet 23b.fwdarw.positive electrode sheet 23a. In the present embodiment, the front-rear direction indicated by the arrow Y3 is the stacking direction of the electrode bodies 21 (the positive electrode sheet 23a and the negative electrode sheet 23b).

  As shown in FIG. 3, each electrode lead 27 for the positive electrode is divided into a plurality (six in this embodiment) in the stacking direction (front-rear direction) of the electrode body 21, and each electrode lead 27 is separated from the plurality of electrode leads 27. Six electrode current collectors 28a, 28b, and 28c are formed. Similarly, each electrode lead 27 for negative electrode is divided into a plurality (six in this embodiment) in the stacking direction (front-rear direction) of the electrode body 21, and six electrode current collectors each including a plurality of electrode leads 27. A portion 28 is formed. In the following description, the electrode current collectors 28a, 28b, and 28c are collectively referred to as an electrode current collector 28 unless otherwise distinguished.

  In this manner, the electrode lead 27 (electrode current collector 28) for the positive electrode and the electrode lead 27 (electrode current collector 28) for the negative electrode are located above (the lid) at the end (upper edge) of the electrode body 21. It is formed to extend (extend) toward the member 13 side. In the present embodiment, the vertical direction is the extending direction (extending direction) of each electrode lead 27 (electrode current collector 28).

  As shown in FIG. 1, in the secondary battery 10 of the present embodiment, the electrode lead 27 for the positive electrode (electrode current collector 28) and the positive electrode terminal 15 are connected by a current collecting terminal 30 as a current collecting member. Electrically connected. Further, the negative electrode lead 27 (electrode current collector 28) and the negative electrode terminal 16 are electrically connected by a current collecting terminal 31 as a current collecting member. Hereinafter, the connection structure (junction structure) by the current collection terminals 30 and 31 is demonstrated in detail.

  The current collecting terminal 31 of the present embodiment has the same configuration (shape) as the current collecting terminal 30, and the connection structure between the current collecting terminal 31 and the negative electrode lead 27 (electrode current collecting portion 28) is as follows. This is symmetrical to the connection structure between the current collecting terminal 30 and the positive electrode lead 27 (electrode current collecting portion 28). Therefore, in the following description, the configuration of the current collector terminal 30 and the connection structure between the current collector terminal 30 and the positive electrode lead 27 (electrode current collector 28) will be mainly described in detail. The junction structure between the current collecting terminal 31 and the negative electrode lead 27 (electrode current collecting portion 28) is denoted by the same reference numeral, and the description thereof is omitted or simplified.

  As shown in FIG. 3, the current collecting terminal 30 is made of metal (for example, aluminum or copper), and is orthogonal to the stacking direction of the electrode body 21 and the extending direction of the electrode lead 27 (electrode current collecting portion 28) as a whole. It has a flat plate-like main body 30a extending along the direction (left-right direction). That is, the main body 30a (the current collecting terminal 30) is formed along the direction in which the upper edge 24b of the metal foil 24a constituting the positive electrode sheet 23a extends. The width in the front-rear direction of the main body 30a is the same (substantially the same) as the thickness in the front-rear direction of the electrode body 21, and the length in the left-right direction of the main body 30a is the left-right direction in each electrode current collector 28. The outer edge portion (left edge portion in the present embodiment) and the left and right edge portions (left edge portion in the present embodiment) of the electrode body 21 are flush with each other (substantially flush). The main body 30a has a base end 30b that is one end in the direction in which the upper edge 24b of the metal foil 24a extends, and a tip 30c that is the other end. Both the base end portion 30b and the tip end portion 30c of the present embodiment are formed in a planar shape.

  And the front-end | tip part 30c side among the main-body parts 30a has comprised the isosceles triangle shape by planar view extended toward the outer side (front-end | tip part 30c side) of the left-right direction from the base end part 30b side. Thereby, the cross-sectional area S cut | disconnected by the surface orthogonal to the direction where the upper edge part 24b of the metal foil 24a extends is small in the main-body part 30a of this embodiment toward the front-end | tip part 30c side from the base end part 30b side. A reduced portion 32 is formed.

  That is, the cross-sectional area S of the main body portion 30a increases from the distal end portion 30c side to the proximal end portion 30b side in the reduced portion 32. In the main body portion 30a, the cross-sectional area S is formed to be constant on the base end portion 30b side of the reduction portion 32. In addition, the current collecting terminal 30 of the present embodiment is electrically connected to the positive electrode terminal 15 at a position on the base end portion 30 b side in the reduced portion 32.

  As shown in FIGS. 3 and 4, the lower surface (part) disposed on the electrode body 21 side in the reduced portion 32 of the main body 30 a is electrically connected to the positive electrode lead 27 (electrode current collector 28). While being connected, a plurality of connection portions 35a to 35c are arranged (formed) side by side in the direction (left-right direction) in which the upper edge portion 24b of each metal foil 24a extends. Therefore, the reduction part 32 of this embodiment is formed in the position where each connection part 35a-35c is provided.

  Each connection part 35a-35c is extended along the direction where the upper edge part 24b of the metal foil 24a is extended, and is mutually parallel. That is, each connection part 35a-35c is suspended from the lower surface of the reduction | decrease part 32 along the surface direction of the electrode lead 27 (positive electrode sheet 23a and negative electrode sheet 23b).

  And among each connection part 35a-35c, the connection part 35a is set so that the left end surface arrange | positioned in the outer side of the left-right direction in the electrode body 21 may become flush | planar (substantially flush) with the front-end | tip part 30c which makes planar shape. And in the current collection terminal 30, it forms in the center of the front-back direction. Further, the two connection portions 35b and 35c remaining in the current collecting terminal 30 are disposed on the base end portion 30b side with respect to the connection portion 35a so as to sandwich the connection portion 35a from both sides in the front-rear direction in the left side view. Yes. In other words, the connection portions 35 a to 35 c are arranged along the edge of the reduction portion 32, and are arranged in a triangular shape in plan view.

  As shown in FIG. 5, the current collecting terminal 30 is arranged so that the connecting portions 35 a to 35 c are inserted between the electrode current collecting portions 28. Specifically, the connection portion 35a is inserted between the electrode current collector portions 28a, the connection portion 35b is inserted between the electrode current collector portions 28b, and the connection portion 35c is It is inserted between the electrode current collectors 28c.

  Each electrode current collector 28a is bonded to the front surface and the rear surface of the connection portion 35a, and each electrode current collector 28b is bonded to the front surface and the rear surface of the connection portion 35b. The electrode current collector 28c is joined to the front surface and the rear surface of the connection portion 35c. Each of the electrode current collectors 28 is joined by, for example, ultrasonic welding or resistance welding (spot welding) in a state where the electrode current collectors 28 are close to (connected to) the connection portions 35a to 35c.

  When joining by ultrasonic welding, a connecting portion and an electrode current collector to be welded are inserted by inserting a horn formed in a rod shape and a jig from the end in the left-right direction between the electrode current collectors 28. 28 is performed in such a state that the horn is vibrated and the horn is vibrated while applying a predetermined load in this state. Also, when joining by resistance welding, a pair of electrodes formed in a rod shape are inserted between the electrode current collectors 28 from the ends in the left-right direction, so that the connection parts and electrode current collectors to be welded are inserted. 28 is performed by energizing the substrate 28 while applying a predetermined load in this state.

Next, the operation of the secondary battery 10 (connection structure) configured as described above will be described.
As shown in FIG. 5, when discharging or charging is performed via the positive terminal 15 and the negative terminal 16, the positive terminal 15 and the positive electrode lead 27 (electrode current collector 28) are connected via the current collecting terminal 30. ) (Current indicated by arrow Y4). At this time, the current flowing through the main body 30a (the current collecting terminal 30) flows from the distal end portion 30c side where the single connection portion 35a is provided to the base end portion 30b side where the two connection portions 35b and 35c are provided (positive electrode terminal). 15 side) and may easily generate heat (Joule heat generation) on the base end 30b side. However, in the current collecting terminal 30 of the present embodiment, the cross-sectional area S in the direction orthogonal to the direction in which the upper edge portion 24b extends particularly increases at the positions where the connection portions 35a to 35c are formed. The reduction | decrease part 32 is formed so that it may become. For this reason, the electrical resistance (resistance value) at the position where the connection portions 35a to 35c are formed becomes smaller as the proximity to the proximal end portion 30b. The same applies to the current collecting terminal 31 having the same configuration as the current collecting terminal 30.

  Therefore, in the present embodiment, even when the current flowing through the reduced portion 32 in the main body portion 30a increases as it approaches the base end portion 30b, heat generation due to energization can be suitably suppressed. In addition, when each current collection terminal 30 and 31 generate | occur | produces excessive heat | fever, the temperature rise in case 11 (electrode body 21) will be caused, and it will become easy to generate | occur | produce thermal runaway by this, for example, or generation | occurrence | production of thermal runaway is prevented. For example, the amount of energy required for temperature adjustment (particularly cooling) of the secondary battery 10 to be increased may adversely affect the performance of the secondary battery 10 (electrode body 21).

  In the present embodiment, the current collector terminals 30 and 31 are provided with a plurality of connection portions 35a to 35c. Therefore, the electrode lead 27 can be divided into a plurality of electrode current collectors 28 (electrode current collectors 28a, 28b, 28c) and connected to the connection portions 35a to 35c. For example, when all the electrode leads 27 are brought close to each other and connected to one connection portion, the electrode leads 27 of the positive electrode sheet 23a or the negative electrode sheet 23b that are close to the connection portion in the stacking direction (front-rear direction) of the electrode bodies 21. As a result, there is a surplus at the tip, which causes a shift in the upper end of the electrode current collector 28 so as to incline in the front-rear direction. However, in this embodiment, by providing each connection part 35a-35c, the electrode lead 27 is divided | segmented and joined, the gap | deviation produced in the upper end of each electrode current collection part 28 is made small, and generation | occurrence | production of a dead space is suppressed. ing.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The main body portion 30a of the current collecting terminal 30 has an upper edge at a position where the connection portions 35a to 35c to which the electrode leads 27 (non-application region 25) not coated with the active material are electrically connected are provided. The cross-sectional area S cut | disconnected by the surface orthogonal to the direction where the part 24b extends has the reduction | decrease part 32 which becomes small toward the front-end | tip part 30c from the base end part 30b. The current collecting terminal 30 is electrically connected to the positive electrode terminal 15 at a position on the base end portion 30 b side in the reduced portion 32 of the current collecting terminal 30. For this reason, the electrical resistance (resistance value) in the position where the connection parts 35 a to 35 c are provided in the current collecting terminal 30 (main body part 30 a) becomes smaller as it is closer to the connection position between the current collecting terminal 30 and the positive electrode terminal 15. Become. The same applies to the connection structure between the current collecting terminal 31 and the negative electrode terminal 16. Therefore, heat generation due to energization can be suppressed.

  (2) And in this embodiment, it suppresses that the main-body part 30a (each current collection terminal 30 and 31) generate | occur | produces a heat | fever with electricity supply, and adversely affects the performance as the secondary battery 10 by this heat_generation | fever. Can be suppressed.

  (3) The main body 30a is provided with a plurality of connecting portions 35a to 35c. For this reason, the electrode lead 27 can be divided into small portions and connected to the connection portions 35a to 35c. Compared to the configuration in which all the electrode leads 27 are connected to each other and connected to one connection portion, It is possible to reduce the deviation of the end face of the electrode lead 27 (electrode current collector 28) generated by connecting the connecting portion. Therefore, the dead space in the case 11 can be reduced.

(4) Since the electrode current collectors 28 are connected to the connection portions 35a to 35c so as to sandwich the connection portions 35a to 35c, the connection portions 35a to 35c and the electrode current collectors 28 are connected to each other. The electrical resistance (resistance value) at the connection portion can be reduced.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same reference numerals are given to the same configurations as those of the already described embodiments, and the overlapping description is omitted or simplified.

  As shown in FIG. 6, the electrode body 21 of the present embodiment is a state in which the separator 22, the positive electrode sheet 23 a, and the negative electrode sheet 23 b are formed in a strip shape (long sheet shape) and the separator 22 is interposed therebetween. In the sandwiched state, the positive electrode sheet 23a and the negative electrode sheet 23b are wound in a spiral shape so that the positive electrode sheet 23a and the negative electrode sheet 23b are layered.

  More specifically, as shown in FIG. 7, in the positive electrode sheet 23a (metal foil 24a), an edge 24c (left edge in the present embodiment) which is one side in the width direction (shown by an arrow Y1) is provided. The non-application region 25 is formed so as to extend along the length direction (indicated by the arrow Y5) of the positive electrode sheet 23a, and the non-application region 25 is formed to extend to the outer side (left side) in the width direction. The positive electrode lead 27 is used. Similarly, in the negative electrode sheet 23b, an uncoated region 25 extends along the length direction of the negative electrode sheet 23b at the edge 24c (the right edge in the present embodiment) which is the other side in the width direction. The non-application area 25 is formed as an electrode lead 27 for a negative electrode extending outward (right side) in the width direction.

  Then, by winding the positive electrode sheet 23a and the negative electrode sheet 23b with the separator 22 interposed, a positive electrode lead 27 is formed in a layered manner over a plurality of layers at the left end portion of the electrode body 21. An electrode current collector 28 is formed. Similarly, at the right end of the electrode body 21, a negative electrode current collector 28 is formed in which a negative electrode lead 27 is layered over a plurality of layers. That is, electrode leads 27 (electrode current collectors 28) are respectively formed at both ends (both edges) of the electrode body 21 in the direction in which the winding axis extends (left and right direction), and the electrode leads 27 ( It can be said that the electrode current collector 28) has a flat annular shape that continues in the circumferential direction of the electrode body 21. In the present embodiment, the horizontal direction is the extending direction of each electrode lead 27 (electrode current collector 28).

  Further, as shown in FIG. 8, in the current collecting terminal 30 of the present embodiment, the main body 30a is disposed along the upper edge and the left edge of the electrode body 21 by bending the metal plate at a right angle. It is formed in an inverted L shape when viewed from the front. In other words, the main body 30a extends from the extending portion 33a having a rectangular flat plate shape extending toward the outside (left) of the electrode body 21 in the left-right direction, and the outer end (left end) of the extending portion 33a. It is comprised from the flat hanging part 33b suspended so that it might extend along the left edge part of the electrode current collection part 28 (electrode lead 27) for positive electrodes. That is, in the present embodiment, the hanging portion 33b of the current collecting terminal 30 is formed along the direction (vertical direction) in which the electrode lead 27 (edge portion 24c) of the positive electrode sheet 23a extends.

  The hanging portion 33b has an isosceles triangular shape in a side view extending downward from the extending portion 33a. Thereby, in the drooping portion 33b of the current collecting terminal 30, the cross-sectional area S cut along a plane perpendicular to the direction (vertical direction) in which the edge 24c of the metal foil 24a constituting the electrode lead 27 extends is the base end portion 30b. A reduced portion 32 is formed that decreases from the side toward the distal end portion 30c. Since the current collecting terminal 30 of the present embodiment is electrically connected to the positive electrode terminal 15 in the extending portion 33a, the current collecting terminal 30 is connected to the positive electrode terminal 15 at a position closer to the base end portion 30b than the reduced portion 32 in the main body portion 30a. Electrically connected.

  In addition, a surface (part) disposed on the electrode body 21 side in the hanging portion 33b (reduced portion 32) is electrically connected to the electrode lead 27 (electrode current collecting portion 28) for the positive electrode, and the positive electrode sheet A plurality of connection portions 35a and 35b are arranged (formed) side by side in the direction (left-right direction) in which the edge portion 24c of the metal foil 24a constituting the portion 23a extends.

  Each connection part 35a, 35b is extended along the direction where the edge part 24c of the metal foil 24a which comprises the positive electrode sheet 23a is extended, and it is mutually parallel. In other words, the connection portions 35 a and 35 b are formed to extend from the side surface of the reduced portion 32 along the extending direction of the electrode lead 27.

  As shown in FIGS. 6 and 9, the current collecting terminal 30 of the present embodiment is configured such that the connection portions 35 a and 35 b are positive electrode collecting portions 28 from the outer side (left side) of the electrode body 21 in the left-right direction. It is arranged so as to be inserted between (electrode leads 27). One electrode current collector 28a is joined to the front surface of the connection portion 35a, while one electrode current collector 28b is joined to the front surface of the connection portion 35b.

  In the present embodiment, the electrode current collector 28 is not connected (joined) to the rear surfaces of the connection portions 35a and 35b. Therefore, when joining by ultrasonic welding, the connection part to be welded and the electrode current collector part 28 are sandwiched from the front and rear direction by a horn formed in a rod shape and a jig, and a predetermined load is applied in this state. This is done by vibrating the horn while giving In addition, when joining by resistance welding, the connection part to be welded and the electrode current collector part 28 are sandwiched from the front and rear direction by a pair of electrodes formed in a rod shape, and a predetermined load is applied in this state. It is done by energizing while.

  The current collecting terminal 31 of the present embodiment has the same configuration (shape) as the current collecting terminal 30, and the connection structure between the current collecting terminal 31 and the negative electrode lead 27 (electrode current collecting portion 28) is as follows. The connection structure between the current collecting terminal 30 and the positive electrode lead 27 (electrode current collecting portion 28) is bilaterally symmetric.

Therefore, according to this embodiment, in addition to the effects (1) to (4) of the first embodiment, the following effects can be obtained.
(5) The electrode body 21 can be easily formed by winding the positive electrode sheet 23a and the negative electrode sheet 23b. Even in such a wound electrode body 21, the electrical resistance (resistance value) at the position where the connecting portions 35 a and 35 b are provided in the main body portion 30 a of the current collecting terminal 30 is the same as that of the current collecting terminal 30. The closer to the connection position with the positive electrode terminal 15, the smaller it is, and the heat generation due to energization can be suppressed. The same applies to the connection structure between the current collecting terminal 31 and the negative electrode terminal 16.

  (6) The electrode current collector 28 of the present embodiment has an annular shape that is continuous in the circumferential direction of the electrode body 21. For this reason, the connecting portions 35a and 35b provided on the current collecting terminals 30 and 31 are inserted between the electrode current collecting portions 28 from the directions (vertical and horizontal directions) perpendicular to the winding axis of the electrode body 21. I can't. However, in each current collection terminal 30 and 31 of this embodiment, each connection part 35a and 35b is provided by providing each connection part 35a and 35b in the surface (part) arrange | positioned at the electrode body 21 side in the hanging part 33b. It can be easily inserted between the electrode current collectors 28. For this reason, in this embodiment, each connection part 35a, 35b and the electrode lead 27 (electrode current collection part 28) can be connected easily.

The embodiment is not limited as described above, and may be embodied as follows, for example.
In the first embodiment, any one of the connection portions 35b and 35c may be omitted. Further, as shown in FIG. 10, in the second embodiment, a connecting portion 35c may be provided instead of or in addition to the connecting portion 35b. In the second embodiment, when the connection portion 35b and the connection portion 35c are formed, an insertion hole 30d for inserting a joining jig (horn, support base, electrode, or the like) may be provided.

  Further, as shown in FIG. 10, each connection portion 35a, 35b is formed to extend from a surface (part) disposed on the electrode body 21 side of the main body portion 30a, and the extension of each connection portion 35a, 35b. You may form so that the cross-sectional area cut | disconnected by the surface orthogonal to a protrusion direction may become small toward the edge part of the front end side of connection part 35a, 35b. Further, when the connection portion 35c is formed instead of or in addition to the connection portion 35b, the connection portion 35c can be configured in the same manner. Further, the same changes can be made in the first embodiment. According to this, each connection part 35a-35c can be easily inserted between the electrode leads 27 (electrode current collection part 28).

  As shown in FIG. 11, the reduced portion 32 has a cross-sectional area S cut along a plane orthogonal to the direction in which the upper edge portion 24b of the metal foil 24a extends, gradually decreasing from the base end portion 30b toward the tip end portion 30c. You may form so that it may become. Even if comprised in this way, the electrical resistance (resistance value) in the position in which the connection parts 35a-35c are provided can be made small, so that it comes close to the connection position of the current collection terminal 30 and the positive electrode terminal 15. FIG. In addition, although the current collection terminal 30 in 1st Embodiment was illustrated in FIG. 11, it can change similarly about the current collection terminal 30 in 2nd Embodiment. Further, the current collecting terminal 31 can be similarly changed.

  Further, the shape of the reduced portion 32 in each of the current collecting terminals 30 and 31 can be appropriately changed as long as the cross-sectional area S is formed smaller from the base end portion 30b toward the tip end portion 30c. For example, the reduced portion 32 (main body portion 30a) may be formed in a conical shape or a pyramid shape having the tip portion 30c as a vertex.

O The reduction | decrease part 32 may be formed in the main body part 30a of the current collection terminals 30 and 31 over the whole.
O The non-application area | region 25 may be formed along the some edge part among the edge parts (side) of the metal foil 24a which comprises the positive electrode sheet 23a and the negative electrode sheet 23b.

  Each of the current collecting terminals 30 and 31 may be configured to have four or more connecting portions. In this case, the electrode body 21 may be formed with the number of electrode current collectors 28 corresponding to the number of connection portions provided in the current collector terminals 30 and 31.

  ○ Each of the connecting portions 35a to 35c is formed so that two parallel wall portions make a pair, and an electrode lead 27 (electrode current collecting portion 28) is disposed between each wall portion and caulked, thereby The connecting portions 35a to 35c and the electrode lead 27 may be connected (joined). That is, the connection portions 35a to 35c may be connected to the electrode lead 27 (electrode current collector 28) so as to sandwich the electrode lead 27 (electrode current collector 28) from both sides. According to this, since the connection portions 35 a to 35 c are connected so as to sandwich the electrode lead 27 (non-application region 25), the electrical resistance (resistance value) at the connection portion between each connection portion 35 a to 35 c and the electrode lead 27. ) Can be reduced.

  The arrangement positions of the connection portions 35a to 35c in the current collecting terminals 30 and 31 may be changed as appropriate. In this case, the reduction part 32 may be formed at the position where the connection parts 35a to 35c are provided.

The current collecting terminals 30 and 31 may be appropriately changed in the width in the front-rear direction and the length in the left-right direction.
(Circle) in 1st Embodiment, you may connect one electrode current collection part 28 to each connection part 35a-35c, respectively. Moreover, in 2nd Embodiment, you may connect the electrode current collection part 28 to each connection part 35a, 35b so that it may pinch | interpose from both surfaces of the front-back direction.

The electrode body 21 may be laminated by bending the positive electrode sheet 23a and the negative electrode sheet 23b in a bellows shape with the separator 22 interposed therebetween.
(Circle) you may change suitably the number of the positive electrode sheet 23a which comprises the electrode body 21, and the negative electrode sheet 23b. For example, the electrode body 21 may include one positive electrode sheet 23a and one negative electrode sheet 23b.

  The active material layer 26 may be formed by applying an active material only to one surface of the metal foil 24a on the positive electrode sheet 23a and the negative electrode sheet 23b. That is, the active material layer 26 may be formed by applying the active material to at least one surface of the positive electrode sheet 23a and the negative electrode sheet 23b.

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 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 can suppress that the performance as the secondary battery 10 is adversely affected by the heat generation at the current collecting terminals 30 and 31. Therefore, it can suppress that the replacement cycle of the secondary battery 10 becomes short.

  -You may apply to the electrical double layer capacitor as an electrical storage apparatus.

  S ... Cross-sectional area, 10 ... Secondary battery (power storage device), 15 ... Positive electrode terminal (external terminal), 16 ... Negative electrode terminal (external terminal), 21 ... Electrode body, 22 ... Separator, 23a ... Positive electrode sheet, 23b ... Negative electrode Sheet, 24a ... Metal foil (metal sheet), 24b ... Upper edge (side), 24c ... Edge (side), 25 ... Non-coated area (uncoated part), 27 ... Electrode lead, 30 ... Current collecting terminal (Current collecting member), 30a ... Main body part, 30b ... Base end part, 30c ... Tip part, 31 ... Current collecting terminal (current collecting member), 32 ... Reduction part, 35a-35c ... Connection part.

Claims (6)

A layered electrode body with a sheet-like separator sandwiched between a positive electrode sheet and a negative electrode sheet on which at least one surface of the metal sheet is coated with an active material, and the electrode body and external terminals are electrically connected A current collecting member connected electrically, and a connection structure comprising:
The positive electrode sheet and the negative electrode sheet are each formed with at least one uncoated portion where no active material is applied,
A plurality of the current collecting members are arranged side by side in the extending direction of the one side while being electrically connected to the uncoated portion provided on the main body, and a main body electrically connected to the external terminal Having a connection portion,
The main body has a base end that is one end in the extending direction of the one side and a tip that is the other end, and the one side extends at a position where the connecting portion is provided. A cross-sectional area cut along a plane orthogonal to the direction has a reduced portion that decreases from the base end portion toward the tip end portion, and is located at a position closer to the base end portion in the reduced portion or the reduced portion in the main body portion. Is also electrically connected to the external terminal at a position on the base end side.   The connecting portion is formed to extend from a portion of the main body portion disposed on the electrode body side, and a cross-sectional area cut along a plane orthogonal to the extending direction of the connecting portion is on the distal end side of the connecting portion. The connection structure according to claim 1, wherein the connection structure decreases toward an end portion.   The connection structure according to claim 1, wherein the connection portion is connected to the uncoated portion so as to sandwich the uncoated portion from both sides.   In the electrode body, the positive electrode sheet and the negative electrode sheet are layered by winding the positive electrode sheet and the negative electrode sheet, and both ends of the electrode body in the extending direction of the winding axis are respectively The connection structure according to claim 1, wherein the uncoated portion is formed.   5. The power storage device according to claim 1, wherein the electrode body and the external terminal are electrically connected via the current collecting member by the connection structure according to claim 1.   A vehicle comprising the power storage device according to claim 5.