JP2013196959A - Power storage device, secondary battery and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device which can reduce a dead space of the power storage device in comparison with a conventional technique if a junction area between a tab part and a collector terminal is the same, and easily joint the tab part and the collector terminal, also provide a secondary battery and a vehicle.SOLUTION: A tab part 12 includes: a collection part which is a part from the bottoms of the tab parts to a position where the tab parts overlap; a straight advance part which is closer to a tip side than the collection part and extends in a direction in which the tab part projects; and a folding part which is closer to the tip side than the straight advance part and formed by being folded from the straight advance part. A collection terminal 13 includes a first member 17 and a second member 18 which hold the tab parts therebetween. The first and second members respectively include a holding surface 19c and a holding surface 18d for holding the folding part. A slit 18a to which the straight advance part is inserted is formed on one of the first member and the second member which is closer to an electrode 11. The tab part disposed in a position closest to the first member side among the plurality of tab parts is jointed to the holding surface of the first member, and the tab part disposed in a position closest to the second member side among the plurality of tab parts is jointed to the holding surface of the second member.

Description

  The present invention relates to a power storage device, a secondary battery, and a vehicle, and particularly relates to a rechargeable power storage device, a secondary battery, and a vehicle equipped with the power storage device, such as a secondary battery and a capacitor.

  2. Description of the Related Art Secondary batteries such as nickel metal hydride secondary batteries and lithium ion secondary batteries use an electrode in which an active material is applied (supported) on a current collector made of metal foil. A laminated electrode body (power generation element) laminated with a separator sandwiched between a plurality of positive electrode current collectors and a plurality of negative electrode current collectors, or a strip-shaped positive electrode current collector A secondary battery is configured by accommodating a wound electrode body wound in a substantially long cylindrical shape with a strip-shaped separator sandwiched between a current collector and a strip-shaped negative electrode current collector together with an electrolyte solution in a battery case Is done. And extraction of the electric power from an electrode body is performed via the current collection terminal connected to the active material non-application part (tab part) of a collector.

  As shown in FIG. 8, the electrode tabs (dub portions) 52 of the plurality of electrode plates 51 are inserted into slits 54 arranged in parallel to the current collecting comb 53 as shown in FIG. There has been proposed a configuration in which a connecting member 56 having a pole column 55 is electrically connected to the current collecting comb 53. The connecting member 56 has a plurality of ridges 57 that sandwich the current collecting comb 53. The pole column 55 means an electrode terminal of the secondary battery.

Japanese Patent Laid-Open No. 11-25951

  In the current collecting structure of Patent Document 1, the electrode tab 52 is joined to the current collecting comb 53 in a state of being inserted into the plurality of slits 54. Therefore, in order to increase the bonding area between each electrode tab 52 and the current collecting comb 53, it is necessary to increase the protruding length of the electrode tab 52 from the electrode plate 51 and to increase the thickness of the current collecting comb 53. There is. As a result, there is a problem that the distance from the base end of the electrode tab 52 to the surface of the current collecting comb 53 opposite to the surface facing the electrode plate 51 increases, and the dead space of the secondary battery increases. In addition, a plurality of electrode tabs 52 are usually inserted into one slit 54, but in order to facilitate the insertion of the plurality of electrode tabs 52, the width of the slit 54 needs to be widened. However, if the width of the slit 54 is increased, it is difficult to uniformly weld the plurality of electrode tabs 52 and the current collecting comb 53 inserted in the slit 54, and the joint portion between the electrode tab 52 and the current collecting comb 53 is difficult. There is also a problem that the electrical resistance increases. In addition, this problem is not limited to the current collecting structure in the secondary battery, but also applies to the power storage device such as a capacitor.

  The present invention has been made in view of the above problems, and its object is to reduce the dead space of the power storage device as compared with the conventional technology if the joint area between the tab portion and the current collecting terminal is the same. It is another object of the present invention to provide a power storage device, a secondary battery, and a vehicle on which the power storage device can be mounted, in which the tab portion and the current collecting terminal can be easily joined.

  In order to achieve the above object, the invention according to claim 1 is a power storage device that is electrically connected to a current collecting terminal in a state where a plurality of tab portions protrudingly formed on the electrode are stacked, the tab portion being A collecting portion that is a portion between the base of the tab portion and the tab portion overlapping, a rectilinear portion extending in a protruding direction of the tab portion on the distal end side from the collecting portion, and a distal end side from the rectilinear portion. And a bent portion formed by bending from the straight portion. The current collecting terminal includes a first member and a second member that sandwiches the tab portion in cooperation with the first member, and the first member and the second member are the tab portions in the bent portion. In the overlapping direction of the first member and the second member, the rectilinear portion is inserted into the first member and the second member closer to the electrode. A slit is formed. The tab portion arranged closest to the first member among the plurality of tab portions is joined to the clamping surface of the first member, and is most adjacent to the second member among the plurality of tab portions. The tab portion disposed on the second member is joined to the clamping surface of the second member.

  In the present invention, in the current collecting terminal, the clamping surfaces of the first member and the second member having a clamping part that clamps the tab part clamp the tab part. The tab portion is sandwiched between the sandwiching surfaces in a state where a plurality of bent portions are stacked between the sandwiching surfaces. The tab portion arranged closest to the first member among the plurality of tab portions is joined to the clamping surface of the first member, and the tab portion arranged closest to the second member among the plurality of tab portions is second. It is joined to the clamping surface of the member. And since it can respond by enlarging a clamping surface in order to enlarge the junction area of a tab part and a clamping surface, ie, the junction area of a tab part, and a current collection terminal, unlike conventional technology, The distance from the base end to the surface opposite to the surface facing the electrodes of the first member and the second member does not change, and there is no problem that the dead space of the power storage device increases. If the joint area of the tab portion and the current collecting terminal is the same, the distance from the base end of the tab portion to the surface opposite to the surface facing the electrodes of the first member and the second member is shortened. Compared to the technology, the dead space of the power storage device can be reduced. Also, even if the width of the slit is widened in order to facilitate the insertion of a plurality of tab portions, unlike the conventional technology, the tab portions are not joined to both sides of the slit, so that the joining state is adversely affected. Absent. Therefore, if the joint area between the tab portion and the current collecting terminal is the same, the dead space of the power storage device can be reduced as compared with the prior art, and the tab portion and the current collecting terminal can be easily joined. it can.

  According to a second aspect of the present invention, in the first aspect of the present invention, the plurality of tab portions include at least two groups that are bent in opposite directions, respectively, in the stacking direction of the tab portions in the rectilinear portion. It is joined to the first member and the second member in a state. In this invention, when joining a tab part and the 1st member and the 2nd member by pressure bonding, compared with the case where it joins in the same position in the state where all of a plurality of tab parts were piled up, force required for pressure bonding is obtained. Can be small. In addition, when the tab portion and the first member and the second member are joined by welding, the entire tab can be welded uniformly as compared to the case where welding is performed at the same position in a state where all of the tab portions are overlapped. It becomes easy.

  Invention of Claim 3 has two slits spaced apart in the lamination direction of the tab part in the rectilinear advance part as the slit in the invention of Claim 1 or Claim 2, and a plurality of the tabs The section has at least two groups that pass through each of the slits, and the two groups are folded in the direction of approaching each other in the stacking direction of the tab section in the rectilinear section, and the folded sections of the two groups overlap each other. The part is joined to the clamping surface of the first member and the clamping surface of the second member.

  Each tab portion is guided to a joint location with respect to the first member and the second member through the slit, and the bending angle of the tab portion according to the distance between the base end of each tab portion and the slit, that is, the base end of the tab portion The angle formed by the portion between the slit and the slit is different from the surface of the current collector, and the bending portion becomes larger as the tab portion is farther away. When the bending angle increases, the bending force applied to the tab portion due to expansion / contraction of the current collector during charge / discharge of the power storage device increases, and the tab portion is likely to deteriorate. In this invention, since it has two slits spaced apart in the stacking direction of the tab portion in the rectilinear portion, the value that maximizes the distance between the base end of the tab portion and the slit is a configuration in which one slit is provided. The maximum bending angle of the tab portion is also smaller than that of the configuration in which one slit is provided. Therefore, the tab portion is less likely to be deteriorated than in the case of one slit.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the tab portion is joined to the first member and the second member by welding. In this invention, compared with the case where a tab part, a 1st member, and a 2nd member are electrically connected by crimping | bonding, the electrical resistance of a junction part becomes small.

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein the tab portion, the first member, and the second member are the first member and the second member. Any one of the members is joined to each other in a state of being caulked and fixed to the other. In this invention, welding work becomes unnecessary for the joining work of a tab part, a 1st member, and a 2nd member.

  The power storage device according to any one of claims 1 to 5, wherein the electrode includes a positive electrode and a negative electrode, and has a separator that insulates the positive electrode from the negative electrode. It is a secondary battery. Therefore, the secondary battery of this invention has the effect of the invention as described in any one of Claims 1-5.

  A seventh aspect of the invention is a vehicle equipped with the power storage device according to any one of the first to fifth aspects. Therefore, the vehicle of the present invention can obtain the effect of the power storage device. In addition, when a power storage device with reduced dead space is mounted, it is easier to secure a space for mounting on a vehicle than a power storage device with the same capacity, and the degree of freedom of the vehicle body structure is increased.

  According to the first to sixth aspects of the present invention, the dead space of the power storage device can be reduced as compared with the prior art if the joint area between the tab portion (active material non-applied portion) and the current collecting terminal is the same. In addition, it is possible to provide a power storage device and a secondary battery in which the tab portion and the current collecting terminal can be easily joined. According to invention of Claim 7, the vehicle from which the effect of the said electrical storage apparatus is acquired can be provided.

The 1st embodiment is shown, (a) is a partial schematic diagram of an electrode body, (b) is a partially omitted schematic sectional view in the AA line of (a), and (c) is a perspective view of the 2nd member. The schematic cross section corresponding to before the welding of the figure of FIG.1 (b). The schematic cross section of a secondary battery. The 2nd Embodiment is shown, (a) is a partial schematic diagram of an electrode body, (b) is a schematic cross section corresponding to FIG. The 3rd embodiment is shown, (a) is a fragmentary perspective view of the 1st member, and (b) is a schematic sectional view corresponding to Drawing 4 (b). (A), (b) is a schematic cross section of another embodiment. The schematic cross section of the secondary battery of another embodiment. The perspective view which shows the current collection structure of a prior art.

(First embodiment)
A first embodiment in which the present invention is embodied in a stacked secondary battery will be described below with reference to FIGS.

  As shown in FIGS. 1A and 1B, the current collector terminal connection structure of the electrode body 10 in the secondary battery as the power storage device collects current in a state where a plurality of tab portions 12 provided on the electrode 11 are stacked. In this configuration, the terminal 13 is electrically connected. As shown in FIG. 1B, the electrode body 10 has a configuration in which a positive electrode 11p and a negative electrode 11n as electrodes 11 are stacked in a plurality of layers with a separator 14 between them being sandwiched therebetween. FIG. 1B is schematically drawn for easy understanding of the configuration of the electrode body 10, and in actuality, the number of positive electrodes 11p and negative electrodes 11n is several tens.

  The electrode 11 has an active material layer 16 in which an active material is applied to a metal current collector 15. The current collector 15 is formed of, for example, copper foil, and the active material layer 16 is formed on both surfaces of the current collector 15. The current collector 15 is provided with an active material non-applied portion 15a continuously on one end side in the width direction, and on the upper end side in FIG. 12 are joined by welding. The tab portion 12 is formed to protrude from the electrode. In FIG. 1B, the tab portion 12 and the current collector 15 are shown integrally, and hatching of electrodes and the like is omitted.

  The active material varies depending on the type of secondary battery such as a nickel metal hydride battery and a lithium ion battery. In addition, when the electrode body 10 is configured even in the same type of secondary battery, the electrode body 10 is different from the one applied to the positive electrode serving as the positive electrode 11p and the one applied to the negative electrode serving as the negative electrode 11n.

  The current collecting terminal 13 includes a metal first member 17 and a metal second member 18 that cooperates with the first member 17 to sandwich the tab portion 12. As shown in FIG. 1A, the first member 17 includes a main body portion 19 having a plate-like holding portion 19 a for holding the tab portion 12, and a column portion 20 extending perpendicularly to the main body portion 19. Yes. As shown in FIG. 1B, the main body 19 is formed with bent portions 19b extending along both sides of the sandwiching portion 18c of the second member 18 so as to be continuous with the sandwiching portion 19a. The column part 20 constitutes an electrode terminal of a secondary battery to be described later, and the column part 20 is formed with a male screw part 20a.

  As shown in FIG. 1C, the second member 18 is formed of a rectangular flat plate, has a slit 18a extending in the longitudinal direction thereof, and a tapered portion that becomes wider toward the opening end side on the opening side of the slit 18a. 18b is formed. As shown in FIG. 1 (a), the slit 18a is formed in the width direction of the tab portion 12 (left and right in FIG. 1 (a)) when the second member 18 cooperates with the first member 17 to sandwich the tab portion 12. Direction). The portions on both sides of the second member 18 sandwiching the slit 18a constitute the clamping portion 18c. Here, “extending in the width direction of the tab portion” is not limited to being parallel to the width direction of the tab portion, but includes a case where the tab portion is inclined within ± 30 degrees.

As shown in FIGS. 1A and 1B, the second member 18 is located between the body portion 19 of the first member 17 and the electrode 11, and cooperates with the first member 17 to form a tab portion. 12 is sandwiched.
As shown in FIG. 1 (b), the tab portion 12 extends obliquely in the assembly portion (FIG. 1 (b)) that is a portion between the base (base end) of the tab portion 12 and the tab portion 12 overlapping. Part), a rectilinear portion extending in the protruding direction of the tab portion 12 on the tip side from the collecting portion, and a bent portion formed by being bent from the rectilinear portion on the tip side from the rectilinear portion. In FIG. 1 (b), the straight part is a part extending through the slit 18a and extending in the vertical direction, and the bent part is shown in FIG. 1 (b) after passing through the slit 18a and then in the horizontal direction (horizontal direction). It is an extended part.

  The main body portion 19 and the second member 18 of the first member 17 are provided on both sides of the bent portion in the overlapping direction of the tab portion 12 in the bent portion, and have a holding surface 19c and a holding surface 18d that sandwich the bent portion, respectively. A slit 18 a into which the rectilinear portion is inserted is formed in the main body portion 19 of the first member 17 and the second member 18 closer to the electrode 11 (in this embodiment, the second member 18).

  Of the plurality of tab portions 12, the tab portion 12 disposed closest to the first member 17 is joined to the clamping surface 19 c of the first member 17. Of the plurality of tab portions 12, the tab portion 12 disposed closest to the second member 18 is joined to the clamping surface 18 d of the second member 18. The plurality of tab portions 12 include the first member 17 and the first member 17 in a state including two groups that are bent in opposite directions in the stacking direction of the tab portions 12 in the rectilinear portion with the rectilinear portion inserted into the slit 18a. The two members 18 are joined. In this embodiment, the tab portion 12 is joined (welded) to the first member 17 and the second member 18 by resistance welding.

  In the first member 17 and the second member 18, the clamping surfaces 19 c and 18 d of the plate-like clamping portions 19 a and 18 c that clamp the tab portion 12 are virtual extension surfaces of the surface of the electrode 11 (in FIG. 1A, parallel to the paper surface). The tab portion 12 is sandwiched in a state extending in a direction intersecting with the other plane, preferably in a direction perpendicular to the plane.

Next, the manufacturing method (assembly method) of the electrode body 10 provided with the current collection terminal connection structure comprised as mentioned above is demonstrated.
The manufacturing method of the electrode body 10 first prepares a current collector base formed of a strip-shaped metal foil. The current collector base is the length of the plurality of electrodes 11 of the laminated electrode body 10, and the width is the width of the region where the active material is applied and the width of the active material non-application portion 15 a that joins the tab portion 12. With total width. The active material is applied to the current collector substrate to form the active material layer 16 on both sides. The positive electrode active material is applied to the positive electrode current collector substrate, and the negative electrode active material is applied to the negative electrode current collector substrate. Next, the tab portion 12 is welded at a predetermined interval to the active material non-applied portion 15a of the current collector base material on which the active material layer 16 is formed. Thereafter, the current collector substrate is cut to the length of the electrode 11 to form the positive electrode 11p and the negative electrode 11n. Note that the tab portion 12 may be welded after the current collector base material on which the active material layer 16 is formed is cut to the length of the electrode 11.

  Next, a predetermined number of positive electrodes 11p and negative electrodes 11n are stacked with a separator 14 in between. As shown in FIG. 3, the tabs 12p of the positive electrode 11p are arranged in a state where they overlap at the same position, and the tab parts 12n of the negative electrode 11n overlap each other at a position where they do not overlap with the tab part 12p of the positive electrode 11p. Be placed. In this state, the current collecting terminals 13 are joined to the tab portion 12p of the positive electrode 11p and the tab portion 12 of the negative electrode 11n, respectively.

  The tab portion 12p of the positive electrode 11p will be described as an example. First, in a state where the tab portion 12p is gathered, the second member 18 is moved to insert an intermediate portion (straight forward portion) of the tab portion 12p gathered in the slit 18a. . Next, the tab portion 12p at the tip side from the portion inserted into the slit 18a is divided into two groups, and each group is bent in the opposite direction along the clamping surface 18d of the second member 18, respectively. At this time, the positions of the tips of the tab portions 12p are not the same, and the bending angle θ of the tab portion 12p (shown in FIG. 1B) depends on the distance between the base end of each tab portion 12p and the slit 18a, that is, the tab portion. As the angle formed between the base end of 12p and the slit 18a and the surface of the current collector 15 increases, the tip protrudes from the clamping surface 18d. As a result, the tab portion 12 has a gathering portion, a rectilinear portion, and a bent portion from the root side.

  Next, as shown in FIG. 2, the main body portion 19 is arranged at a position where the holding portion 19 a can be held in cooperation with the holding portion 18 c of the second member 18. In this state, the clamping surfaces 19c and 18d clamp the tab portion 12p in a state where the projection 19d formed on the clamping surface 19c is in contact with a part of the tab portion 12p. Further, the bent portion 19b engages with the tip of the tab portion 12p that has come out of the clamping surface 18d to bend the tip of the tab portion 12p. In FIG. 2, the negative electrode 11n, the separator 14, and the active material layer 16 are not shown.

  Next, the tab portion 12p is joined to the first member 17 and the second member 18 by projection welding, which is a type of resistance welding. In projection welding, current and pressure are concentrated on the protrusion 19d, and welding is performed in a state where the current density is increased with a small current. After the end of welding, the protrusion 19d disappears, and the tab 12p is joined (welded) to the first member 17 and the second member 18 by resistance welding as shown in FIG. 1 (b). . Similarly, the tab 12n of the negative electrode 11n is joined to the current collecting terminal 13 to complete the electrode body 10.

  In the collector terminal connection structure of the electrode body 10 configured as described above, the junction area between the tab portion 12 and the clamping surfaces 19c and 18d, that is, the junction area between the tab portion 12 and the collector terminal 13 is increased. This can be dealt with by enlarging the clamping surfaces 19c and 18d. Since the clamping surfaces 19c and 18d are arranged in a state extending in a direction intersecting with the virtual extension surface of the surface of the electrode 11, even if the clamping surfaces 19c and 18d are enlarged, the base of the tab portion 12 is different from the prior art. The distance from the end to the surface opposite to the surface facing the electrode 11 of the first member 17 and the second member 18 does not change, and there is no problem that the dead space of the secondary battery increases. Moreover, if the joint area of the tab part 12 and the current collection terminal 13 is the same, it will be from the base end of the tab part 12 to the surface on the opposite side to the surface facing the electrode 11 of the 1st member 17 and the 2nd member 18. By reducing the distance, the dead space of the secondary battery can be reduced as compared with the prior art. Further, even if the width of the slit 18a is widened to facilitate the insertion of the plurality of tab portions 12, the tab portion 12 is not joined to both surfaces of the slit 18a unlike the prior art, which adversely affects the joined state. Will not affect. Therefore, if the joining area of the tab part 12 and the current collection terminal 13 is the same, the dead space of a secondary battery can be reduced compared with a prior art, and also the joining of the tab part 12 and the current collection terminal 13 can be achieved. It can be done easily.

  As shown in FIG. 3, the electrode body 10 is accommodated in a battery case (battery case) 31, and a secondary battery 30 is configured together with an electrolytic solution 32. The electrode body 10 has a battery case 31 by a nut 34 screwed to the male screw portion 20a in a state where the column portion 20 of the current collecting terminal 13 penetrates the packing 33 made of an insulating material and the lid portion of the battery case 31. Fixed to. The column portion 20 of the current collecting terminal 13 joined to the tab portion 12p for the positive electrode 11p constitutes the positive electrode terminal 35 of the secondary battery 30, and the current collecting terminal 13 joined to the tab portion 12n for the negative electrode 11n. The column portion 20 constitutes the negative electrode terminal 36 of the secondary battery 30. That is, the secondary battery 30 (power storage device) is electrically connected to the current collecting terminal 13 in a state where a plurality of tab portions 12 protruding from the electrode 11 are stacked.

The secondary battery 30 configured as described above is used for various purposes. For example, the secondary battery 30 is also used in a state of being mounted on a vehicle.
According to this embodiment, the following effects can be obtained.

  (1) The collector terminal connection structure of the secondary battery 30 as the power storage device is a current collector in a state where a plurality of tab portions 12 (tab portions 12p, 12n) provided on the electrode 11 (positive electrode 11p, negative electrode 11n) are stacked. It is electrically connected to the terminal 13. The tab portion 12 includes a collective portion that is a portion between the base of the tab portion 12 and the tab portion 12 overlapping, a rectilinear portion that extends in a protruding direction of the tab portion 12 on the distal end side from the collective portion, and a distal end from the rectilinear portion And a bent portion formed by being bent from the straight portion on the side. The current collecting terminal 13 includes a first member 17 and a second member 18 that cooperates with the first member 17 to sandwich the tab portion 12. The first member 17 and the second member 18 are provided on both sides of the bent portion in the overlapping direction of the tab portion 12 in the bent portion, and have clamping surfaces 19c and 18d that sandwich the bent portion, respectively. A slit 18a into which the rectilinear portion is inserted is formed on the second member 18 closer to the electrode 11 (in this embodiment, the second member 18). The tab portion 12 arranged closest to the first member 17 among the plurality of tab portions 12 is joined to the clamping surface 19c of the first member 17, and the second member 18 side most among the plurality of tab portions 12. The tab portion 12 disposed on the second member 18 is joined to the clamping surface 18 d of the second member 18. Therefore, if the joint area of the tab part 12 and the current collection terminal 13 is the same, the dead space of the secondary battery 30 can be reduced compared with the prior art, and the joint between the tab part 12 and the current collection terminal 13 can be reduced. Can be easily performed.

  (2) The plurality of tab portions 12 are joined to the first member 17 and the second member 18 so as to include at least two groups bent in opposite directions in the stacking direction of the tab portions 12 in the rectilinear portion. ing. Therefore, when joining the tab part 12 and the 1st member 17 and the 2nd member 18 by welding, compared with the case where it welds in the same position in the state which accumulated all the several tab parts 12, the whole is uniform. It becomes easy to weld.

  (3) The tab portion 12 is joined to the first member 17 and the second member 18 by welding. Therefore, when the tab portion 12, the first member 17 and the second member 18 are electrically connected by crimping. In comparison, the electrical resistance of the joint is reduced.

  (4) The first member 17 has a plate-like clamping portion 19a for clamping the tab portion 12, and a bent portion 19b extending along both sides of the clamping portion 18c of the second member 18 is formed continuously to the clamping portion 19a. Has been. Since some of the tab portions 12 are joined to the holding portions 19a and 18c with their tips protruding in the width direction of the holding portions 19a and 18c, when there is no bent portion 19b, the tips of the tab portions 12 are connected to the battery. There is a risk that a short circuit may occur due to contact with the case 31. Therefore, it is necessary to adjust the length of the tab portion 12 so that the tip of the tab portion 12 protruding from the sandwiching portion 19a has a length that does not contact the battery case 31. However, when the bent portion 19b exists, even if the tab portion 12 protruding from the sandwiching portion 19a is long, the tab portion 12 engages with the bent portion 19b and bends toward the electrode 11 side. Since contact with 31 is avoided, there is no need to adjust the length of the tab portion 12.

  (5) Since the secondary battery 30 includes the current collector terminal connection structure having the above-described configuration, the effect of the current collector terminal connection structure can be obtained. Moreover, the junction area of the tab part 12 and the current collection terminal 13 of the electrical power collector 15 can be increased, current collection efficiency can improve, and output density can be raised.

  (6) A vehicle equipped with the secondary battery 30 can obtain the effects of the secondary battery 30. Further, when the secondary battery 30 with reduced dead space is mounted, it is easier to secure a space for mounting on the vehicle than the secondary battery 30 with the same capacity, and the degree of freedom of the vehicle body structure is increased. Get higher.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. 4 (a) and 4 (b). In this embodiment, the tab portion 12 is joined to the first member 17 and the second member 18 in a state in which the sandwiching portion 19a of the first member 17 is disposed closer to the electrode 11 than the second member 18, and the tab The point from which the slit which inserts the rectilinear part (intermediate part) of the part 12 is provided in the 1st member 17 side differs from the said 1st Embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4A, the main body portion 19 of the first member 17 is formed to be bent halfway, and the portion where the column portion 20 is provided is disposed at a position farther from the electrode 11 than the sandwiching portion 19a. Has been. As shown in FIG. 4B, a slit 19e is formed in the clamping part 19a. The surface on the side away from the electrode 11 of the clamping part 19a constitutes the clamping surface 19c.

  As shown in FIG. 4B, the slit 18a is not provided in the second member 18, and in the state before welding, the protrusion 18e is located at a position facing the clamping surface 19c of the first member 17 of the second member 18. Is provided. The second member 18 is formed wider than the first member 17, and the second member 18 is formed with bent portions 18 f extending along both sides of the holding portion 19 a of the first member 17 so as to be continuous with the holding portion 18 c. ing.

  In this embodiment, in the state where the plurality of tab portions 12 are overlapped, the intermediate portion (straight forward portion) is inserted into the slit 19e of the first member 17, and the front end side of the portion inserted into the slit 19e is the clamping surface 19c. Are joined to the first member 17 and the second member 18 in a state of being bent along the line. Therefore, in order to join the tab portion 12 to the first member 17 and the second member 18, first, an intermediate portion (straight forward portion) of the tab portion 12 is inserted into the slit 19 e of the first member 17. Next, the front end side of the intermediate portion (straight forward portion) of the tab portion 12 inserted into the slit 19e is divided into two groups, bent in opposite directions along the clamping surface 19c, and in this state, the second member 18 is moved. The first member 17 is assembled so as to cover the clamping part 19a. In this state, resistance welding is performed to join the tab portion 12 to the first member 17 and the second member 18.

  Accordingly, also in this embodiment, the protrusions 19d and 18e and the bent portions 19b and 18f are different in which one of the first member 17 and the second member 18 is provided, but (1) to (1) in the first embodiment. Basically the same effect as (6) can be obtained.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. In this embodiment, a plurality of slits 19e (two in this embodiment) are provided in the clamping part 19a of the first member 17, and a tab part 12 in which an intermediate part (straight forward part) is inserted in each slit 19e. The point which is joined to the 1st member 17 and the 2nd member 18 in the state where the tip side was piled up without being divided into two from the middle part of is greatly different from a 2nd embodiment. The same parts as those of the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 5A and 5B, two slits 19e are formed in the clamping portion 19a. And the upper surface of the clamping part 19a of the part pinched by the two slits 19e comprises the clamping surface 19c. The second member 18 is formed narrower than the sandwiching portion 19a, and the bent portion 18f is not formed. Further, the protrusion 18 e is formed at the center of the second member 18. That is, as the slits, there are two slits 19e that are separated in the stacking direction of the tab portion 12 in the rectilinear portion. The plurality of tab portions 12 include at least two groups passing through the slits 19e, and the two groups are bent in a direction approaching each other in the stacking direction of the tab portions 12 in the rectilinear portion, and each of the bent portions of the two groups The overlapped portion is joined to the clamping surface 19 c of the first member 17 and the clamping surface 18 d of the second member 18.

  In this embodiment, the plurality of tab portions 12 are divided into two groups, and the intermediate portions (straight advance portions) are inserted into different slits 19e of the first member 17 in a state where they are overlapped for each group. The first member 17 and the second member 18 are joined in a state where the distal end side is bent along the holding surface 19c from the portion inserted into the slit 19e. As shown in FIG. 5 (b), since the clamping surface 19c is one place, the tab portions 12 that are divided into two groups and inserted into different slits 19e are in a state in which the portions on the tip side from the intermediate portion overlap each other. And is sandwiched between the first member 17 and the second member 18 in a state of being placed on the clamping surface 19c and pressed by the protrusion 18e. The tab portion 12 is joined to the first member 17 and the second member 18 by resistance welding.

Therefore, in the current collector terminal connection structure of this embodiment, the following effects can be obtained in addition to the basically same effects as (1) and (3) of the first embodiment. .
(7) A plurality of (two) slits 19e are provided, and the plurality of tab portions 12 are divided into two groups, and an intermediate portion (straight forward portion) is inserted into different slits 19e, and then the tip side from the intermediate portion Is bent along the clamping surface 19c. Each tab portion 12 is guided to a joint portion with respect to the first member 17 and the second member 18 through the slit 19e, and the tab portion 12 has a distance between the base end (base) of each tab portion 12 and the slit 19e. The bending angle, that is, the angle formed between the base end of the tab portion 12 and the slit 19e and the surface of the current collector 15 is different, and the bending portion becomes larger as the tab portion 12 is farther away. When the bending angle increases, the bending force applied to the tab portion 12 due to expansion / contraction of the current collector 15 during charging / discharging of the secondary battery 30 increases, and the tab portion 12 tends to deteriorate. In this embodiment, since a plurality of slits 19e are provided, the value at which the distance between the base end of the tab portion 12 and the slit 19e is maximum is smaller than that in the configuration in which one slit 19e is provided, and the tab The maximum bending angle of the portion 12 is also smaller than in the configuration in which one slit 19e is provided. Accordingly, the tab portion 12 is less likely to be deteriorated than in the case where the number of the slits 19e is one.

  (8) Even if the tab portion 12 inserted into the slit 19e is only bent at the tip side of the intermediate portion (straight forward portion) along the clamping surface 19c, the tip end of the tab portion 12 is the first member. It does not protrude from the 17 pinching portions 19a. Therefore, it is not necessary to form the bent portion 18f in the second member 18, and the structure of the second member 18 is simplified.

The embodiment is not limited to the above, and may be embodied as follows, for example.
When the tab portion 12 is welded to the first member 17 and the second member 18 by resistance welding, the resistance welding is not limited to projection welding, and may be resistance welding performed without providing the projections 19d and 18e. Moreover, you may weld the tab part 12 to the 1st member 17 and the 2nd member 18 not only by resistance welding but other welding methods, for example, ultrasonic welding.

  O You may join the tab part 12, the 1st member 17, and the 2nd member 18 by another method instead of welding. For example, the tab portion 12, the first member 17, and the second member 18 may be joined to each other in a state in which one of the first member 17 and the second member 18 is caulked and fixed to the other. Good. Specifically, as shown in FIG. 6A, the tip of the bent portion 19b of the first member 17 is bent inward, and the holding portion 18c of the second member 18 is moved to the holding portion 19a side of the first member 17. The second member 18 may be fixed to the first member 17 by caulking so as to press. Further, as shown in FIG. 6B, the tip of the bent portion 18f of the second member 18 is bent inward so that the holding portion 19a of the first member 17 is pressed toward the holding portion 18c of the second member 18. Alternatively, the second member 18 may be fixed to the first member 17. In these cases, the tab portion 12 is clamped between the clamping surfaces 19c and 18d in a state of being crimped to each other, and the tab portion arranged closest to the first member 17 among the plurality of tab portions 12 is clamped by the first member. The tab portion 12 that is joined to the surface 19 c and is disposed closest to the second member 18 among the plurality of tab portions 12 is joined to the clamping surface 18 d of the second member 18. Therefore, welding work is not necessary for the joining work of the tab portion 12, the first member 17, and the second member 18.

O Crimping and welding by caulking may be used in combination for joining the tab portion 12, the first member 17, and the second member 18.
○ Even in the configuration in which a plurality of slits 19e are provided, the portion on the front end side of the straight portion (intermediate portion) of the tab portion 12 inserted into each slit 19e is divided into two parts, and the first portion is bent along the clamping surface 19c. The first member 17 and the second member 18 may be joined.

In the configuration in which the slit 18a is provided in the second member 18 as in the first embodiment, a plurality of slits 18a may be provided.
In the configuration in which one slit 18a or 19e is provided, the slits 18a and 19e may be formed not at the center of the sandwiching portions 18c and 19a but at a position offset to one side in the width direction of the sandwiching portions 18c and 19a. In this case, the first end portion of the tab portion 12 inserted into the slits 18a and 19e is bent along the sandwiching surfaces 18d and 19c without being divided into two portions. Joined to the member 17 and the second member 18.

  The present invention is not limited to the stacked electrode body 10 and may be applied to a wound electrode body 10. In that case, as shown in FIG. 7, the tab portion 12p for positive electrode and the tab portion 12n for negative electrode protrude on different sides of the electrode body 10, and the electrode terminal of the secondary battery 30, that is, the positive electrode terminal 35 and The protruding direction of the negative electrode terminal 36 from the battery case 31 may be different from the protruding direction of the tab portion 12 from the electrode body 10. In this case, the shape of the main body portion 19 of the current collecting terminal 13 is different from that in each of the embodiments.

The laminated electrode body 10 may also have a configuration in which the positive electrode tab portion 12p and the negative electrode tab portion 12n protrude on different sides of the electrode body 10.
The current collecting terminal 13 is not limited to a configuration in which the portions serving as the electrode terminals of the secondary battery 30 are integrally formed, and the main body portion 19 may have a configuration without the column portion 20. In this case, the main body portion 19 is fixed to the battery case while being supported by a support portion (fixing portion) provided on the secondary battery side, and is electrically connected to the electrode terminal or directly to the electrode terminal. It is formed in a configuration that is supported and fixed.

O The method of fixing the current collecting terminal 13 to the electrode terminal (positive terminal or negative terminal) is not limited to the configuration using screwing of the threaded portion.
The first member 17 and the second member 18 are tabs in a state in which the clamping surfaces 19c, 18d of the plate-like clamping portions 19a, 18c that clamp the tab portion 12 extend in a direction intersecting the virtual extension surface of the surface of the electrode 11. What is necessary is just to pinch | interpose the part 12, and it is not necessary to extend in the direction orthogonal to the said virtual extension surface. However, it is preferable to be close to orthogonal in the range of assembly errors and component manufacturing errors.

The electrode 11 (positive electrode 11p, negative electrode 11n) is not limited to the configuration having the active material layer 16 on both sides of the current collector 15, but may have a configuration having the active material layer 16 on one side of the current collector 15.
The tab portions 12, 12p, and 12n are not limited to the configuration in which a member formed separately from the current collector 15 is joined to the active material non-applied portion 15a of the current collector 15 by welding, and the active material of the current collector 15 The structure integrally formed continuously with the non-application part 15a may be sufficient. However, in the case where the tab portion 12 and the like are continuously formed integrally with the active material non-applied portion 15a, the portion that does not become the tab portion 12 and the like is wasted because it is removed from the active material non-applied portion 15a. Occurs.

  When the distal end side is bent along the clamping surfaces 19c and 18d from the rectilinear portion (intermediate portion) of the tab portion 12 inserted into the slit 19e of the first member 17 or the slit 18a of the second member 18, the electrode body 10 is The length of the tab portion 12 may be adjusted by the tab portion 12 in order to prevent (avoid) the tip of the tab portion 12 from contacting the battery case 31 in the state of being accommodated in the battery case 31. In this case, there is no problem even if the bent portion 19b of the first member 17 and the bent portion 18f of the second member 18 are omitted.

  (Circle) the electrode body 10 is not limited to the electrode body used for the secondary battery 30, The electrode body used for capacitors, such as an electric double layer capacitor and a lithium ion capacitor, may be sufficient.

  DESCRIPTION OF SYMBOLS 11 ... Electrode, 11p ... Positive electrode as an electrode, 11n ... Negative electrode as an electrode, 12, 12n, 12p ... Tab part, 13 ... Current collecting terminal, 14 ... Separator, 17 ... 1st member, 18 ... 2nd member, 18a , 19e ... slits, 18c, 19a ... clamping parts, 18d, 19c ... clamping surfaces, 30 ... secondary batteries as power storage devices.

Claims (7)

A power storage device that is electrically connected to a current collecting terminal in a state in which a plurality of tab portions formed to protrude from an electrode are stacked,
The tab portion includes a collective portion that is a portion from the base of the tab portion to the overlap of the tab portion, a rectilinear portion extending in a protruding direction of the tab portion on the tip side from the collective portion, and the rectilinear portion A bent portion formed by being bent from the rectilinear portion on the more distal end side,
The current collecting terminal includes a first member, and a second member that cooperates with the first member to sandwich the tab portion,
The first member and the second member are provided on both sides of the bent portion in the overlapping direction of the tab portion in the bent portion, and each have a sandwiching surface sandwiching the bent portion,
A slit into which the rectilinear portion is inserted is formed on the first member and the second member closer to the electrode,
The tab portion arranged closest to the first member among the plurality of tab portions is joined to the clamping surface of the first member, and is most adjacent to the second member among the plurality of tab portions. The power storage device according to claim 1, wherein the tab portion disposed on the second member is joined to the clamping surface of the second member.   The plurality of tab portions are joined to the first member and the second member in a state including at least two groups bent in opposite directions in the tabular stacking direction of the rectilinear portion. Item 2. The power storage device according to Item 1.   The slit has two slits spaced apart in the stacking direction of the tab portion in the rectilinear portion, and the plurality of tab portions have at least two groups passing through the slits, and the two groups advance the rectilinearly In the stacking direction of the tab portion in the portion, the bent portions of the two groups are joined to the clamping surface of the first member and the clamping surface of the second member. The power storage device according to claim 1 or claim 2.   The power storage device according to any one of claims 1 to 3, wherein the tab portion is joined to the first member and the second member by welding.   The said tab part, the said 1st member, and the said 2nd member are mutually joined in the state in which any one of the said 1st member and the said 2nd member was fixed with respect to the other. Item 4. The power storage device according to any one of Items 3 to 3.   6. The secondary battery according to claim 1, wherein the electrode includes a positive electrode and a negative electrode, and further includes a separator that insulates the positive electrode from the negative electrode.   A vehicle equipped with the power storage device according to any one of claims 1 to 5.