JP5086566B2 - Electricity storage element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power storage element capable of connecting a current collector foil and a plate-shape terminal by welding jointing even if the number of current collection foil becomes many. <P>SOLUTION: The power storage element comprises a wound-around body 8 or a laminate in which a positive electrode part and a negative electrode part are arranged so as to interpose a separator and a plate-shape terminal 2 in which respectively the positive electrode part and the negative electrode part are connected through a plurality of layers of current collection foil 9. A plurality of auxiliary current collection plates 12 are provided which have a current collection jointing part 10 to joint by welding with one of a plurality of bundles bundling separately a plurality of layers of current collection foil 9 and a terminal jointing part 11 to joint by welding with the plate-shape terminal 2. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to power storage elements such as secondary batteries and capacitors.

In recent years, demand for hybrid vehicles, electric vehicles, fuel cell vehicles, and the like has increased, and there has been a demand for further increase in current and miniaturization of storage elements. As a power storage element, a laminated body in which a positive electrode portion and a negative electrode portion are arranged so as to sandwich a separator, and a plurality of layers of current collector foil drawn from each of the positive electrode portion and the negative electrode portion are welded and joined. A structure having a plate-shaped terminal is proposed (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2004-87260 (FIG. 2)

  In a power storage device, it is generally known to increase the areas of the positive electrode portion and the negative electrode portion as a technique for increasing current, that is, charging and discharging a larger current. On the other hand, since the storage element is also required to be miniaturized, at least it is not desirable to increase the volume of the storage element, and it is difficult to end the service life in a short time even if a large current can flow. There is no need to reduce the thickness of the active material formed on the positive electrode portion and the negative electrode portion so as not to decrease. From the above, in order to increase the areas of the positive electrode portion and the negative electrode portion, the current collector foil that becomes a substrate of the active material in the positive electrode portion and the negative electrode portion and collects the generated charges is thinned.

  However, when the area of the positive electrode part and the negative electrode part is enlarged and the current collector foil is made thin, the number of layers of the laminate in which the positive electrode part and the negative electrode part are arranged so as to sandwich the separator increases. This increases the number of current collector foils to be welded to the terminal. If the number of current collector foils that are welded to the plate-shaped terminals increases, the surface layer side of the bundled current collector foils will melt too much and break easily, and the current collector foils on the plate-shaped terminal side will be difficult to melt and will be joined. It became difficult to weld.

  In view of the above points, an object of the present invention is to provide a power storage element that can connect a current collector foil and a plate-like terminal by welding joint even when the number of current collector foils is increased.

In the present invention, a wound body or a laminate in which a positive electrode part and a negative electrode part are arranged so as to sandwich a separator, and each of the positive electrode part and the negative electrode part is a plurality of layers of current collector foil In a power storage device having a plate-like terminal connected via a current collector, a current-collecting joint for welding and joining one of a plurality of bundles obtained by dividing and bundling the plurality of layers of current-collecting foils, and welding and joining the plate-like terminal have a plurality of auxiliary collector plate having a terminal joint, wherein the auxiliary current collector plate, the bending between the terminal joint portions and the collector junction is provided, each of the plurality of said bundles, In the place which weld-joins with the said current collection junction part, it inclines toward the said plate-shaped terminal, It is characterized by the above-mentioned.

  According to the present invention, since the plurality of layers of current collector foils are separately welded and joined for each of the plurality of auxiliary current collector plates, the number of current collector foils welded and joined at one place can be reduced. Specifically, if the current collecting foils are equally divided, the number of current collecting foils can be reduced to the number obtained by dividing the number of current collecting foils by the number of auxiliary current collecting plates, and welding joining can be easily performed.

The auxiliary current collector plate is provided with a bend between the current collector joint portion and the terminal joint portion, and each of the plurality of bundles is connected to the current collector joint portion by welding. Tilt in the direction. Because the bent part is bent at a predetermined angle, the terminal joint is kept along the plate-like terminal, and the current collector foil bundled for welding joint is placed along the current collector joint without forcibly bending. Can be joined. For this reason, the damage by forcibly bending the current collector foil can be prevented.

  Preferably, the plurality of auxiliary current collector plates and the plate-like terminals are provided with positioning holes that overlap each other, and the plurality of terminal joints overlap each other. Since each of the plurality of auxiliary current collecting plates is provided with a positioning hole, the positional relationship in welding with respect to the current collecting foil can be easily reproduced. In addition, a plurality of auxiliary current collector plates and plate terminals are welded to each other through a guide pin so as to pass through the positioning holes of the plurality of auxiliary current collector plates and the plate terminals. The mutual positional relationship between the plate-like terminals can be uniquely determined and fixed.

  The thickness of the auxiliary current collecting plate is preferably thinner than the thickness of the plate-like terminal. The increase in the number of current collector foils makes it difficult not only to weld and join the plate terminals, but also because the current collector foil has a reduced film thickness. It has become difficult. Although the current collector foil is originally thinner than the plate-like terminal, it is considered that the welding connection of the current collector foil to the plate-like terminal becomes more difficult as the ratio of the film thickness of the current collector foil to the plate thickness of the plate-like terminal becomes smaller. Therefore, even if the thickness of the current collector foil is reduced, the thickness of the auxiliary current collector plate to be directly welded is made thinner than that of the plate-like terminal, so that the thickness of the current collector foil relative to the thickness of the auxiliary current collector plate is reduced. Is made smaller than the ratio of the film thickness of the current collector foil to the plate thickness of the plate-like terminal to facilitate welding.

On the contrary, the current charged / discharged in the wound body or laminate flows from the current collector foil through the auxiliary current collector plate to the plate terminal, but the current density at the auxiliary current collector plate is If it is higher than the current density, abnormal heat generation may occur in the auxiliary current collector. Therefore, even if the thickness of each of the plurality of auxiliary current collectors is smaller than the thickness of the plate-like terminal , the current density at the auxiliary current-collecting plate is not higher than the current density at the plate-like terminal. The total thickness of the auxiliary current collector plates is set to be equal to or greater than the plate thickness of the plate-like terminals.

  ADVANTAGE OF THE INVENTION According to this invention, even if the number of current collection foils increases, the electrical storage element which can connect a current collection foil and a plate-shaped terminal by welding joining can be provided.

  As shown in FIG. 1, a power storage device 1 according to an embodiment of the present invention includes an internal structure 6 having plate-like terminals 2 at both ends, an electrolyte solution (not shown) that immerses the internal structure 6, and plate-like terminals 2. The internal structure 6 and the laminate film exterior 3 that seals the electrolyte solution are exposed. The exterior 3 constitutes a sealed bag portion 4 while exposing the plate-like terminal 2 by providing a heat-welded portion 5 in which the outer peripheral portions of the two laminated films are thermally welded over the entire circumference. The internal structure 6 and the electrolyte solution are sealed in the bag portion 4.

  As shown in FIG. 2 and FIG. 3, the internal structure 6 was collected by a wound body 8 that generates current by charging / discharging, and auxiliary current collector plates 12 and 13 that collect the generated current. A plate-like terminal 2 connected to the external device is provided in order to pass a current to the external device. The plate terminal 2 is provided with a fastening hole 15 for fastening to the wiring of the external device. A plurality of layers of current collector foils 9 are provided at both ends of the wound body 8, and current generated in the wound body 8 flows through the current collector foil 9. The current collector foil 9 is welded to the auxiliary current collector plate 12 at the current collector joint 10. The auxiliary current collector plate 12 is welded to the plate-like terminal 2 at the terminal joint portion 11. The auxiliary current collector plate 12 is provided with an alignment hole 14 that can easily reproduce the positional relationship in welding the auxiliary current collector plate 12 to the current collector foil 9.

  As shown in FIG. 3 and FIG. 4A, a plurality of bundles 30 in which a plurality of layers of current collector foils 9 are separately bundled are formed, and one of the bundles 30 and the auxiliary current collector plate 12 are collected. It is welded and joined at the electrical joint 10. The other of the bundles 30 is welded and joined to the auxiliary current collecting plate 13 at the current collecting joint 17. The auxiliary current collector plates 12 and 13 are welded to the plate-like terminals 2 at the terminal joint portions 11 and 16. Since the plurality of layers of current collector foils 9 are separately welded and joined for each of the plurality of auxiliary current collector plates 12 and 13, the number of stacked current collector foils 9 welded and joined at one place can be reduced. Specifically, since the current collecting foil is equally divided into two, the number of stacked sheets can be reduced to half, so that welding can be easily performed. Since the structures of the range C and the range D in FIG. 3 are in a line symmetrical relationship, the details of the range D can be inferred from FIG. 4A which is an enlarged view of the range C.

  Further, the auxiliary current collector plate 12 is provided with a bend 18 between the current collector joint 10 and the terminal joint 11. Similarly, the auxiliary current collecting plate 13 is also provided with a bend 18 between the current collecting joint 17 and the terminal joint 16. Since the auxiliary current collecting plates 12 and 13 are bent by a predetermined angle θ by the bend 18, the terminal joint portions 11 and 16 are welded to the current collecting joint portions 10 and 17 while being along the plate-like terminal 2. Therefore, the bundled current collector foils 9 can be joined along the auxiliary current collector plates 12 and 13 without forcibly bending them. For this reason, it is possible to prevent damage caused by forcibly bending the current collector foil 9. The angle θ is preferably 135 ° or more and 170 ° or less, and within this range, the current collector foil 9 can be joined along the auxiliary current collector plates 12 and 13 without forcibly bending. Moreover, the height of the edge part by the side of the current collection foil 9 of the auxiliary current collection boards 12 and 13 is set to the center height of the bundle 30 to connect. According to this, since only the specific current collector foil 9 is not greatly bent, breakage can be prevented.

  The plate thickness of the auxiliary current collector plates 12 and 13 is thinner than the plate thickness of the plate-like terminal 2. The increase in the number of current collector foils 9 makes it difficult to weld and join the plate-like terminals 2, and the thickness of the current collector foil 9 decreases, thereby reducing the thickness of the current-collecting foil 9 to the plate-like terminals 2. It has become difficult to weld joints. The current collector foil 9 is originally thinner than the plate-like terminal 2, but the current collector foil 9 becomes thinner, so that the ratio of the film thickness of the current collector foil 9 to the plate thickness of the plate-like terminal 2 becomes small. It is considered that only the electric foil 9 is easily melted, and it is difficult to weld the current collecting foil 9 to the plate-like terminal 2. Therefore, even if the film thickness of the current collector foil 9 is reduced, the thickness of the auxiliary current collector plates 12 and 13 to be directly welded and joined is made thinner than that of the plate-like terminal 2, so The ratio of the film thickness of the current collector foil 9 to the thickness is made smaller than the ratio of the film thickness of the current collector foil 9 to the plate thickness of the plate-like terminal 2 so that only the current collector foil 9 is not easily melted during welding. The current collector plates 12 and 13 are also easily melted to facilitate welding.

  As shown in FIG. 4 (b), the plurality of auxiliary current collector plates 12, 13 and the plate-like terminal 2 are provided with positioning holes 14, 19, 20 that overlap each other, and the positioning holes 14, 19, 20 are Communicate. Since the positioning holes 14 and 19 are provided in the plurality of auxiliary current collecting plates 12 and 13 respectively, the positional relationship in welding with respect to the current collecting foil 9 can be easily reproduced.

  Next, the manufacturing method of the electrical storage element which concerns on embodiment of this invention is demonstrated.

  First, the manufacturing method of the wound body 8 is demonstrated with reference to FIG. First, an active material is applied to both surfaces of the strip-shaped current collector foil 9 that becomes the positive electrode except for the right side portion, and the positive electrode portion 21 is formed on the current collector foil 9. Similarly, the active material is applied to both surfaces except the left one side of the other current collector foil 9 serving as a negative electrode, and the negative electrode portion 25 is formed on the current collector foil 9. In order to prevent the positive electrode portion 21 and the negative electrode portion 25 from coming into direct contact with each other, the negative electrode portion 25 is placed on the strip-shaped separator 24 so that the negative electrode portion 25 does not protrude. In addition, the strip-shaped separator 23 is disposed so as to cover the entire negative electrode portion 25, and the positive electrode portion 21 is disposed so as not to protrude from the separator 23. Then, the separator 24, the current collector foil 9 with the negative electrode portion 25, the separator 23, and the current collector foil 9 with the positive electrode portion 21 are flattened while being stacked. Thus, the wound body 8 is completed. In the wound body 8, the positive electrode portion 21 and the negative electrode portion 25 are arranged so as to sandwich the separator 23 and the separator 24 alternately. In addition, when the electrical storage element 1 is a secondary battery, the active material which causes a chemical reaction is needed, but when the electrical storage element 1 is a capacitor, it is not necessary to raise | generate a chemical reaction.

  As shown in FIGS. 6 and 9A, the separators 23 and 24 are wound around one side of the current collector foil 9 where the positive electrode portion 21 or the negative electrode portion 25 is not formed so as not to overlap. Therefore, one side portion of each current collector foil 9 is not covered with the separators 23 and 24 and is exposed to the left and right side portions of the wound body 8.

  As shown in FIG. 7A, the auxiliary current collecting plate 12 is produced by bending a metal plate with a bend 18. An alignment hole 14 is provided on one side of the bend 18. Similarly, the auxiliary current collecting plate 13 is also produced by bending a metal plate with a bend 18 as shown in FIG. An alignment hole 19 is provided on one side of the bend 18. It can be seen that the auxiliary current collecting plate 13 is congruent with the auxiliary current collecting plate 12 when rotated so that the upper and lower sides are switched. If a plurality of auxiliary current collecting plates 12 are manufactured, the auxiliary current collecting plate 12 can be diverted to the auxiliary current collecting plate 13.

  As shown in FIG. 7C, the plate-like terminal 2 is manufactured by providing the alignment hole 20 on one side of the flat plate and the fastening hole 15 on the other side. Since the auxiliary current collecting plate 12, the plate-like terminal 2, and the auxiliary current collecting plate 13 are overlapped and aligned so that the alignment holes 14, 19, and 20 overlap, from the center of the two alignment holes 14 to the center The distance, the distance from the center of the two alignment holes 19 to the center, and the distance from the center to the center of the two alignment holes 20 are set to be equal. Further, if the diameters of the alignment holes 14, 19, 20 are the same, the alignment can be easily performed by inserting a guide pin of the same diameter into the alignment holes 14, 19, 20.

  Next, as shown in FIG. 8 and FIG. 9B, the bundle 30 and the auxiliary current collector plate 12 are sandwiched together while making a bundle 30 by bundling a plurality of layers of current collector foils 9 with a welding machine 27. The current collector foils 9 of the bundle 30 and the auxiliary current collector plate 12 are welded and joined by ultrasonic welding. Three welding locations by this welding become the current collecting joint 10. Prior to welding, the positional relationship between the current collector foil 9 and the auxiliary current collector plate 12 is aligned using the alignment holes 14. Specifically, the auxiliary current collector plate 12 is arranged with respect to the current collector foil 9 so that the distance between the current collector foil 9 and the alignment hole 14 is a predetermined distance.

  As shown in FIG. 9 (c), the bundle 30 and the auxiliary current collector plate 13 are joined together while making another bundle 30 by bundling the remaining layers of the plurality of layers of current collector foils 9 with a welding machine 27. Each of the current collector foils 9 of the bundle 30 and the auxiliary current collector plate 13 are welded and joined by sandwiching and ultrasonic welding. The welding location by this welding becomes the current collecting joint 17. Prior to welding, alignment is performed in the same manner as in the case of the auxiliary current collector plate 12.

  As shown in FIG. 9 (d), a plurality of auxiliary current collector plates 12, 13 and a plate-like terminal 2 are positioned with respect to each other through a guide pin 28 so as to penetrate the positioning holes 14, 19, 20. The auxiliary current collecting plates 12 and 13 and the plate-like terminal 2 are overlapped. A plurality of auxiliary current collector plates 12 and 13 and the plate-like terminal 2 are sandwiched together by a welding machine 27 and welded together by ultrasonic welding. Thus, the mutual positional relationship between the plurality of auxiliary current collecting plates 12 and 13 and the plate-like terminal 2 can be uniquely determined. Although the welding location by this welding becomes the terminal joint parts 11 and 16 (refer Fig.4 (a)), since it weld-joins by one welding, the several terminal joint parts 11 and 16 have mutually overlapped.

  From the above, according to the electricity storage device 1 of the embodiment, even when the number of the current collector foils 9 increases, the current collector foils 9 are divided into a plurality of bundles 30 and welded to the auxiliary current collector plates 12 and 13 respectively. Therefore, since the plurality of auxiliary current collecting plates 12 and 13 are welded and joined to the plate-like terminal 2, the number of current collecting foils 9 for each bundle 30 can be reduced, and good welding joining is possible.

  FIG. 10 shows an internal structure 6 in which an exterior and an electrolyte are removed from a storage element according to another embodiment of the present invention. The power storage element of the other embodiment is different from the power storage element of the embodiment in that the wound body 8 is changed to the stacked body 29. However, the laminated body 29 and the wound body 8 are the same in that a plurality of layers of current collecting foils 9 are provided on both ends, respectively. A plurality of bundles 30 can be formed, and each bundle 30 can be welded to the plurality of auxiliary current collecting plates 12 and 13 one by one. As described above, the embodiment of the present invention can be applied to the laminated body 29 as in the case of the wound body 8. Also, the structure of the laminated body 29 is such that the positive electrode portion and the negative electrode portion are repeatedly arranged with a separator in between, and the current collector foils 9 are provided at both right and left ends from the positive electrode portion and the negative electrode portion. The structure of the wound body 8 is the same in that it is drawn out. Thus, also in other embodiments, the present invention can be carried out similarly to the embodiments, and the same effects can be obtained. That is, even if the current collector foil 9 is thinned and the number of current collector foils 9 is increased, the current collector foil 9 is divided into a plurality of bundles 30 and welded to the auxiliary current collector plates 12 and 13. The number of current collecting foils 9 for each can be reduced, and good welding joining is possible.

It is a perspective view of the electrical storage element which concerns on embodiment of this invention. It is a perspective view of the internal structure which remove | excluded the exterior and the electrolyte from the electrical storage element. It is sectional drawing of the AA direction of FIG. (A) is an enlarged view of the range C of FIG. 3, (b) is an enlarged view of the cross section of the BB direction of FIG. It is a structure figure of a winding body. It is a perspective view of a winding body. (A) is a perspective view of a 1st auxiliary | assistant collector plate, (b) is a perspective view of a 2nd auxiliary collector plate, (c) is a perspective view of a plate-shaped terminal. It is a perspective view in the middle of manufacture of the electrical storage element which concerns on embodiment of this invention. (A) is a figure of the periphery of the collector foil of the cross section of the EE direction of FIG. 6, (b) is a figure of the periphery of the collector foil of the cross section of the FF direction of FIG. ) Is a diagram in which the remaining current collector foil is welded to the second auxiliary current collector plate, and (d) is a diagram in which the first auxiliary current collector plate and the second auxiliary current collector plate are welded to the plate-like terminal. is there. It is a perspective view of the internal structure which remove | excluded the exterior and the electrolyte from the electrical storage element which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power storage element 2 Plate-shaped terminal 6 Internal structure 8 Winding body 9 Current collection foil 10 Current collection junction part 11 Terminal junction part 12, 13 Auxiliary current collection board 14 Positioning hole 16 Terminal junction part 17 Current collection junction part 18 Bending 19, 20 Alignment hole 21 Positive electrode part 23, 24 Separator 25 Negative electrode part 29 Laminate 30 Bundle

Claims (4)

A wound body or laminate in which a positive electrode part and a negative electrode part are arranged so as to sandwich a separator, and each of the positive electrode part and the negative electrode part are connected via a plurality of layers of current collector foils In a storage element having a plate-like terminal,
A plurality of auxiliary current collector plates each having a current collector joint portion that is welded and joined to one of the plurality of bundles obtained by dividing and bundling the current collector foils of the plurality of layers, and a terminal joint portion that is welded and joined to the plate-like terminal; ,
The auxiliary current collector plate is provided with a bend between the current collector joint and the terminal joint,
Each of the plurality of bundles is inclined in the direction of the plate-like terminal at a place where the bundle-welded joint is welded. Each of the plurality of auxiliary current collector plates and the plate-like terminals are provided with positioning holes that overlap each other,
The power storage element according to claim 1, wherein the plurality of terminal joints overlap each other.   3. The power storage device according to claim 1, wherein a thickness of the auxiliary current collecting plate is thinner than a thickness of the plate-like terminal. Total thickness of the auxiliary collector plate of multiple equals the thickness of the plate-like terminals, or power storage device according to claim 3, wherein the greater.

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