JP2008004274A - Electricity storage element - Google Patents

Abstract

Provided is a power storage device that can easily weld a laminated electrode and a current collector plate and reduce dead space in a box-shaped battery can.
A power storage device includes a wound body and a negative electrode and positive electrodes that are wound by laminating and winding electrodes 1a and 1b constituting a negative electrode and a positive electrode and a separator 1s that insulates the electrodes 1a and 1b. Current collector plates 21 and 22 are provided. The wound body 11 includes opposing flat laminated portions 10a and 10b, arc laminated portions 10c and 10d facing and adjacent to the flat laminated portions 10a and 10b, and electrode foil laminated portions extending from the flat laminated portions 10a and 10b. 10e and 10f. The current collecting plate 21 has a pair of current collecting pieces 2a and 2b and a coupling portion 2c that couples the base ends thereof. In the wound bodies 11 and 12, the flat laminated portions 10b and 10b are in contact with each other, and the pair of current collecting pieces 2a and 2b are welded to the opposing electrode foil laminated portions 10e and 10f.
[Selection] Figure 1

Description

  The present invention relates to a power storage element. In particular, the present invention relates to a structure of a winding battery suitable for in-vehicle use such as a lithium ion secondary battery.

  In the wound battery, for example, the electrodes constituting the negative electrode and the positive electrode are coated with an active material on both sides of the metal foil except for the ends. A wound battery constitutes a wound body in which these electrodes are sandwiched between separators, and power storage elements wound tightly in a flat shape are stacked. Further, in the wound battery, a structure in which current collector plates are welded to both ends of the wound body is housed in a battery can.

As such a winding type battery, the ends of the electrodes constituting the separator, the negative electrode, and the positive electrode can be bent without difficulty, and by sandwiching the bent ends with a pair of plate-like members, A wound battery that does not require welding to a current collector plate has been invented (see, for example, Patent Document 1).
JP 2004-241149 A

  FIG. 10 is a perspective external view showing a state in which a pair of plate-like members are attached to a wound body of a wound battery according to Patent Document 1. FIG. FIG. 10 of the present application corresponds to FIG. In FIG. 10, a wound body 81 has a negative electrode and a positive electrode that are wound in a flat shape having a substantially oval cross section through a separator. The end edge of the separator is stuck by a tape 88. The wound body 51 is formed with a straight laminated portion 90 and a pair of arc laminated portions 91. Cutouts 92 are formed at both ends of the arc stack 91.

  In FIG. 10, the exposed portion 90 b in the linear laminated portion 90 is bent up and down from the approximate center in the thickness direction. The pair of exposed portions 90b bent up and down are sandwiched between a pair of substantially U-shaped plate-like members 95a and 95b. Then, the pair of plate-like members 95 forming a pair are inverted to each other, both the plate-like members 65a and 65b are substantially in close contact with each other, and the exposed portion 60b is held therebetween. In this state, the plate-like members 65a and 65b are welded together by, for example, laser welding. In FIG. 10, the code | symbol 96 has shown the welding location.

  For example, a wound battery used in an electric vehicle such as a hybrid vehicle is required to have a high output and has a large number of stacked electrodes joined to a current collector plate. In addition, since the electrodes are extended very thin, there is a problem that it is difficult to join the current collector plate to the stacked electrodes.

  Further, in-vehicle wound batteries use a substantially rectangular parallelepiped box-shaped battery can in order to effectively use the interior space of the vehicle. And the winding body as shown by patent document 1 is accommodated in this box-shaped battery can. However, when the number of windings of the electrode is increased in order to obtain a high output, there is a problem that the arc diameter of the wound body is increased and a dead space is generated in the battery can. A battery structure that reduces dead space in the battery can is desired. The above can be said to be the subject of the present invention.

  The present invention has been made in view of such a problem, and provides a power storage element that can easily join a laminated electrode and a current collector plate and reduce dead space in a box-shaped battery can. With the goal.

  The present inventor makes it easy to join the current collector plate and the stacked electrodes by dividing and arranging the wound body in which the power storage elements are stacked, and to reduce the dead space in the box-type battery can. As a result, the inventors have invented the following new electricity storage device.

  (1) A pair of electrodes constituting a negative electrode and a positive electrode, a pair of wound bodies in which a separator for insulating these electrodes is laminated and wound in a flat shape, and a pair of current collectors connecting these negative electrodes and positive electrodes The winding body includes a pair of opposed flat laminated portions, a pair of arc laminated portions facing each other adjacent to the flat laminated portions, and the pair of flat laminated portions. A pair of electrode foil laminated portions extending in opposite directions from each other, and the current collector plate includes a pair of current collector pieces facing each other, and a coupling portion that couples the base ends of these current collector pieces The pair of wound bodies are arranged such that the flat laminated portions are in contact with each other and the electrode foil laminated portions are opposed to each other, and the pair of current collecting pieces are disposed on the opposed electrode foil laminated portions. Energy storage element.

  The electricity storage device according to the invention of (1) includes a pair of wound bodies and a pair of current collector plates. The wound body is formed by laminating a pair of electrodes constituting a negative electrode and a positive electrode, and a separator for insulating these electrodes, and winding them in a flat shape. Each current collector plate connects negative electrodes and positive electrodes. The wound body has a pair of flat laminated portions, a pair of arc laminated portions, and a pair of electrode foil laminated portions. The pair of flat stacked portions are opposed to each other. A pair of circular arc lamination parts are facing and adjoining these flat lamination parts. The pair of electrode foil laminates extend in opposite directions from the pair of flat laminates.

  In the electricity storage device according to the invention of (1), the current collector plate has a pair of current collector pieces and a coupling portion. The pair of current collecting pieces face each other. The coupling portion couples the base ends of the pair of current collecting pieces. In the pair of wound bodies, the flat laminated portions are in contact with each other. Moreover, a pair of winding body is arrange | positioned so that an electrode foil laminated part may each oppose. And a pair of current collection piece is joined to the electrode foil lamination | stacking part which opposes.

Here, the active material is apply | coated to each electrode of a pair of metal foil to the electrode which comprises a negative electrode and a positive electrode. For example, a carbon material such as graphite is used as the negative electrode active material. As the positive electrode active material, a Li-containing composite oxide such as LiCoO ₂ is used. The separator may electrically insulate a pair of electrodes, and the separator separates both electrodes so that the electrode serving as the negative electrode and the electrode serving as the positive electrode are in direct contact with each other and are not short-circuited. As the separator, a microporous film of polyolefin resin such as polyethylene or polypropylene is usually used. However, the separator is not limited to the above materials.

  The wound body may be formed by alternately laminating a strip-shaped separator and a pair of electrodes constituting a negative electrode and a positive electrode, and the core is pulled out after being wound around a plate-shaped core (core material). . Here, the separator is laminated with both side edges of the pair of electrodes left so that one side edge extending in the axial direction of the wound is a negative electrode and the other side edge is a positive electrode. It is preferable that the active material is applied only to a region where the separator is laminated on each side of the pair of electrodes, and the region where the active material is not applied is overlapped and joined to the current collector plate.

  For each current collector plate, connecting the negative electrodes and the positive electrodes means that the negative electrodes of the pair of wound bodies and the positive electrodes are mechanically and electrically connected to each other. The plate is preferably joined by welding the negative electrode and the positive electrode. As the welding method, ultrasonic welding, laser welding, and resistance welding can be considered. In these welding methods, it is preferable to pressurize or heat the surfaces in such a manner that the surfaces overlap each other, and the joining strength is easily guaranteed.

  Here, when the wound body is viewed from a plane, it is formed in a substantially rectangular shape. Further, when the wound body is viewed from the front, it is a quadrilateral surrounded by a pair of parallel straight lines and a pair of arcs curved outward. The cube is formed in a flat shape. The wound body is provided with a cavity through which the core is pulled out in the winding axis direction as described above. For example, as for a pair of electrode foil lamination | stacking parts, it is preferable that the circular arc lamination | stacking part of both wings in a pair of flat lamination | stacking part is deleted, and only a flat lamination | stacking part is left. And the flat laminated part which opposes through a cavity is bent, and a pair of electrode foil laminated part is formed. Here, one electrode foil lamination part becomes a negative electrode, and the other electrode foil lamination part becomes a positive electrode.

  The coupling portion of the current collector plate may be formed in a U shape or may be formed in a concave shape, and couples the base ends of a pair of current collecting pieces. For example, a current collector plate previously formed in a tuning fork shape may weld a pair of opposed electrode foil laminates, and as will be described later, a current collector plate formed in a strip shape is used in parallel. After joining the electrode foil laminates thus formed, the central part of the current collector plate may be folded to form a U-shaped coupling part. Further, the current collector plate may be welded to the inside of the pair of opposed electrode foil laminated portions, or may be welded to the outside of the pair of opposed electrode foil laminated portions.

  By joining a pair of current collector pieces to the opposing electrode foil laminate, the pair of wound bodies are held by the pair of current collector pieces without being separated from each other. And the electrical storage element by invention of (1) is accommodated in the substantially rectangular parallelepiped box-shaped battery can. Each apex of the bifurcated arc surface of the electric storage element is accommodated so as to abut on the bottom surface of the battery can. The outer walls of the pair of flat laminated portions formed in opposite directions are accommodated so as to slide on the pair of opposed inner walls of the battery can.

  As described above, the power storage device according to the invention of (1) divides the wound body in which the power storage elements are stacked, so that the inner corner of the substantially rectangular parallelepiped box-shaped battery can and the arc surface of the wound body The dead space formed by can be reduced. This is because, when the wound body is housed in the battery can without being divided, the diameter of the arc contacting the corner is increased. It can also be said that the electricity storage element according to the invention of (1) realizes overcrowding accommodation in the battery can, and it can be said that more power generation elements can be accommodated with respect to the constant capacity of the battery can.

  Further, in the electricity storage device according to the invention of (1), the number of electrodes joined to the current collector plate is reduced by half and the joining strength is improved by dividing and arranging the wound body in which the electricity storage elements are laminated. As will be described later, it is preferable that the wound body has an electrode thickness in the range of 5 μm to 50 μm, and the number of electrode foil laminates in the range of 10 to 40.

  (2) In the wound body, the thickness of the electrode is in the range of “5” μm to “50” μm, and the number of stacked electrode foil laminates is in the range of “10” to “40” ( 1) The electrical storage element as described.

  (3) The electricity collecting element according to (1) or (2), wherein the current collector plate includes an external connection terminal in the coupling portion.

  (4) The electricity storage device according to any one of (1) to (3), which is accommodated in a substantially rectangular parallelepiped box-shaped battery can.

  It is preferable that the battery can and the battery can containing a plurality of power storage elements described later be sealed with a lid.

  (5) A substantially rectangular parallelepiped box-shaped battery can that houses a plurality of sets of the electricity storage device according to any one of (1) to (3).

  Preferably, the set of power storage elements is accommodated in a substantially rectangular parallelepiped box-shaped battery can.

  (6) A pair of electrodes constituting a negative electrode and a positive electrode, a pair of wound bodies obtained by laminating a separator that insulates these electrodes and winding them in a flat shape, and a pair of current collectors connecting these negative electrodes and positive electrodes A pair of flat laminated portions facing each other, a pair of arc laminated portions facing each other adjacent to the flat laminated portions, and directions opposite to each other from the pair of flat laminated portions. A pair of electrode foil stacking parts extending to the storage element, wherein the pair of wound bodies are arranged in parallel at a predetermined distance so that the arc stacking parts face each other. A pair of current collector plates formed in a strip shape so that the electrode foil laminates arranged in parallel are welded together, and the pair of current collector plates so that the flat laminate portions abut each other. A bending step of bending the central portion of the Manufacturing method of the power storage element.

  In the method for manufacturing a power storage element according to the invention of (6), the power storage element includes a pair of wound bodies and a pair of current collector plates. The wound body is formed by laminating a pair of electrodes constituting a negative electrode and a positive electrode, and a separator for insulating these electrodes, and winding them in a flat shape. Each current collector plate connects negative electrodes and positive electrodes. The wound body has a pair of flat laminated portions, a pair of arc laminated portions, and a pair of electrode foil laminated portions. The pair of flat stacked portions are opposed to each other. A pair of circular arc lamination parts are facing and adjoining these flat lamination parts. The pair of electrode foil laminates extend in opposite directions from the pair of flat laminates.

  And the manufacturing method of the electrical storage element by invention of (6) includes the arrangement | positioning process, the joining process, and the bending process. In the arranging step, the pair of wound bodies are arranged in parallel at a predetermined distance so that the circular arc stacked portions face each other. In the joining step, the electrode foil laminated portions arranged in parallel are welded using a pair of current collector plates formed in a strip shape. In the bending step, the central portions of the pair of current collector plates are bent so that the flat laminated portions are in contact with each other.

  Arranging the pair of wound bodies in parallel at a predetermined distance may be placing the pair of wound bodies on a flat surface, and in the bending process, the flat plate portions are brought into contact with each other. The separation distance between the pair of wound bodies is determined in consideration of the extension of the current collector plate formed in a shape and the spring back.

  As a joining method in the joining process, welding is preferable, and ultrasonic welding, laser welding, and resistance welding can be considered. In these welding methods, it is preferable to pressurize or heat the surfaces in such a manner that the surfaces overlap each other, and the joining strength is easily guaranteed. In the laser welding method, it is preferable to irradiate a laser on the current collector plate side. In the resistance welding method, it is preferable to devise so as to melt from the current collector plate side.

  Since the manufacturing method of the electrical storage element by invention of (6) has joined the strip | belt-plate-shaped collector plate to the negative electrodes of a pair of wound bodies mounted on the plane, and positive electrodes with each other by welding, There is an advantage that it is easy. For example, a special jig is required when a current collector plate previously formed in a tuning fork shape is resistance welded to a pair of electrode foil laminates. In the laser welding method, it is necessary to irradiate a laser from two surfaces at opposite positions. In any case, productivity is improved by welding a strip-shaped current collector plate between the negative electrodes and the positive electrodes of a pair of wound bodies placed on a plane.

  (7) The method for manufacturing an electric storage element according to (6), further including an external connection terminal attaching step of joining an external connection terminal to a central portion of the pair of current collector plates after the bending step.

  Since the manufacturing method of the electrical storage element according to the invention of (7) further includes an external connection terminal attaching step for joining the external connection terminal to the center part of the pair of current collector plates after the bending step, the current collector plate is bent. Becomes easy. This is because no protrusions are provided during the bending process.

  The power storage device according to the present invention divides the wound body in which the power storage elements are stacked, so that a dead space formed by the inner corner of the substantially rectangular parallelepiped box-shaped battery can and the arc surface of the wound body is formed. Can be reduced. This is because, when the wound body is housed in the battery can without being divided, the diameter of the arc contacting the corner is increased. Further, in the electricity storage device according to the present invention, the number of the electrodes welded to the current collector plate is halved and the bonding strength is improved by separately arranging the wound bodies on which the electricity storage elements are laminated.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is an exploded perspective view showing an embodiment of a power storage device according to the present invention. FIG. 2 is a perspective external view of a wound body constituting the energy storage device according to the embodiment, and is a state diagram before a pair of electrodes and a separator are wound. FIG. 3 is a perspective external view of the electricity storage device according to the embodiment, and is a state diagram in which a pair of current collecting pieces are joined to a pair of wound bodies.

  FIG. 4 is a diagram comparing a power storage element according to the present invention and a power storage element according to the prior art. FIG. 4 (A) is an enlarged vertical cross-sectional view of the main part of the power storage element according to the present invention, and FIG. It is a principal part expansion longitudinal cross-sectional view of the electrical storage element by. FIG. 5 is a diagram comparing a power storage element according to the present invention and a power storage element according to the prior art. FIG. 5 (A) is an enlarged vertical sectional view of a main part of the power storage element according to the present invention, and FIG. It is a principal part expansion longitudinal cross-sectional view of the electrical storage element by. 6 is a diagram comparing a power storage element according to the present invention and a power storage element according to the prior art, and FIG. 6A is a cross-sectional view of the power storage element according to the present invention housed in a battery can. (B) is a cross-sectional view in the state in which the electrical storage element by a prior art was accommodated in the battery can.

  7A and 7B are diagrams related to the method for manufacturing a power storage element according to the present invention. FIG. 7A is a plan view of the power storage element in the bonding step, and FIG. 7B is a front view of the power storage element in the bonding step. FIG. 8 is a front view according to the method for manufacturing the electricity storage device according to the present invention, and is a state diagram before the electricity storage device after the bending step is accommodated in the battery can. FIG. 9 is a longitudinal sectional view according to the method for manufacturing a power storage element according to the present invention, and is a state diagram in which the power storage element after the external connection terminal mounting step is accommodated in a battery can.

  Initially, the structure of the electrical storage element by this invention is demonstrated. In FIG. 1, the electric storage element 10 includes a pair of wound bodies 11 and 12 and a pair of current collector plates 21 and 22. The storage element 10 is accommodated in a substantially rectangular parallelepiped box-shaped battery can 3. The lid 4 seals the battery can 3. In the present invention, the wound body 11 and the wound body 12, and the current collector plate 21 and the current collector plate 22 are all the same, but for the sake of convenience of explanation, the reference numerals are changed for distinction. In the following description, the wound body 11 or the current collector plate 21 may be described as a representative.

  In FIG. 2, a wound body 11 is formed by laminating a pair of electrodes 1a and 1b constituting a negative electrode and a positive electrode, and a separator 1s that insulates the pair of electrodes 1a and 1b. The wound body 11 includes a pair of flat laminated portions 10a and 10b, a pair of arc laminated portions 10c and 10d, and a pair of electrode foil laminated portions 10e and 10f. The pair of flat laminated portions 10a and 10b are opposed to each other. The pair of circular arc stacked portions 10c and 10d are opposed to and adjacent to the pair of flat stacked portions 10a and 10b. The pair of electrode foil laminated portions 10e and 10f extend in directions opposite to each other from the pair of flat laminated portions 10a and 10b (see FIG. 3).

  In FIG. 1, the current collecting plate 21 has a pair of current collecting pieces 2a and 2b and a coupling portion 2c. The pair of current collecting pieces 2a and 2b face each other. The coupling | bond part 2c couple | bonds the base end of a pair of current collection piece 2a * 2b. As for a pair of winding bodies 11 * 12, flat lamination | stacking part 10b * 10b is mutually contact | abutted (refer FIG.2 and FIG.3). The pair of wound bodies 11 and 12 are arranged so that the electrode foil laminated portions 10e and 10e and the electrode foil laminated portions 10f and 10f face each other. And a pair of current collection piece 2a * 2b is joined to electrode foil lamination | stacking part 10e * 10e and electrode foil lamination | stacking part 10f * 10f which oppose.

  In FIG. 2, the wound body 11 is formed by alternately laminating strip-shaped separators 1 s and a pair of electrodes 1 a and 1 b constituting a negative electrode and a positive electrode. The wound body 11 is manufactured by winding the core 1c after being wound around the plate-shaped core 1c. In FIG. 2, the separator 1s is laminated, leaving both side edges of the pair of electrodes 1a and 1b so that one side edge extending in the axial direction of the wound is a negative electrode and the other side edge is a positive electrode. Yes. A tape 1t is attached to the end of the separator 1s. The separator 1s electrically insulates the pair of electrodes 1a and 1b. In addition, the active material is applied only to the region where the separator 1s is laminated on both surfaces of the pair of electrodes 1a and 1b. The regions where the active material is not applied are overlapped and joined to the current collector plates 21 and 22.

  When the wound body 11 is viewed from a plane, it is formed in a substantially rectangular shape (see FIG. 7). When the wound body 11 is viewed from the front, it is a quadrilateral surrounded by a pair of straight lines parallel to each other and a pair of arcs curved outward from each other (see FIG. 7). The wound body 11 is formed in a flat shape as a cube (see FIG. 2). In FIG. 2, the wound body 11 is provided with a cavity 10g through which the core 1c is pulled out and penetrates in the winding axis direction.

  In FIG. 3, the pair of electrode foil laminated portions 10e and 10f are formed with notched portions 10h and 10h in which the arc laminated portions 10c and 10d of both blades in the pair of flat laminated portions 10a and 10b are deleted. Only the portions 10a and 10b are left. Then, the flat laminated portions 10a and 10b facing each other through the cavity 10g are bent to form a pair of electrode foil laminated portions 10e and 10f. In FIG. 2, one electrode foil laminate portion 10e is a negative electrode, and the other electrode foil laminate portion 10f is a positive electrode.

  In FIG. 1, the coupling | bond part 2c of the current collection board 21 is formed in the U-shape, and has couple | bonded the base end of a pair of current collection piece 2a * 2b. In FIG. 1, a current collecting plate 21 formed in a tuning fork shape welds a pair of electrode foil laminated portions 10e and 10e facing each other. As shown in FIG. 3, the electrode foil laminated portions 10e and 10e and the electrode foil laminated portions 10f and 10f arranged in parallel were welded using a pair of current collecting plates 210 and 220 formed in a strip shape. Later, the central portions of these strip-shaped current collector plates 210 and 220 may be bent to form a U-shaped coupling portion 2c (see FIG. 1). In FIG. 1, the current collector plates 21 and 22 are welded to the outer sides of the opposing electrode foil laminate portions 10e and 10f. In addition, the code | symbol 2w in a figure has shown the welding location.

  In FIG. 1, the pair of current collecting plates 21 and 22 includes an external connection terminal 2d in each coupling portion 2c. In the pair of external connection terminals 2d and 2d, the storage element 10 is accommodated in the battery can 3, sealed with the lid 4 and protruded from the lid 4 (see FIG. 9).

  Next, the operation of the electricity storage device according to the present invention will be described. In FIG. 1, by welding a pair of current collecting pieces 2 a and 2 b to the opposing electrode foil laminated portions 10 e and 10 e and the opposing electrode foil laminated portions 10 f and 10 f, the pair of wound bodies 11 and 12 are mutually connected. It is hold | maintained to a pair of current collection piece 2a * 2b, without isolate | separating. The power storage element 10 is accommodated in a substantially rectangular parallelepiped box-shaped battery can 3. Each vertex of the arcuate surface bifurcated in the electricity storage element 10 is accommodated so as to contact the bottom surface of the battery can 3. The outer walls of the pair of flat laminated portions 10 a and 10 a formed in opposite directions are accommodated so as to slide on the pair of opposed inner walls 3 a and 3 a in the battery can 3.

  Referring to FIG. 6, a battery can 3 (see FIG. 6 (A)) containing a power storage element 10 according to the present invention divided and arranged by a pair of wound bodies 11, 12, and a single power storage element 100 according to the prior art. The battery can 3 to be accommodated (see FIG. 6B) has the same volume. Comparing FIG. 6 (A) and FIG. 6 (B), in FIG. 6 (A), the lower dead space BDS and the upper The dead space TDS is formed. On the other hand, in FIG. 6B, the lower dead space BDS and the upper dead space TDS are formed by the inner corners of the battery can 3 and the single arc surface of the power storage element 100.

  In FIG. 6, it can be seen that the planar distance W <b> 1 of the electricity storage element 10 is longer than the planar distance W <b> 2 of the electricity storage element 100, and the arc diameter of the electricity storage element 10 is smaller than the arc diameter of the electricity storage element 100. As described above, the power storage element according to the present invention is formed by dividing the wound body on which the power storage elements are stacked, so that the inner surface corner of the substantially rectangular parallelepiped box-shaped battery can and the arc surface of the wound body are formed. Dead space can be reduced.

  Next, referring to FIG. 4, in FIG. 4 (A) showing the electricity storage device 10 according to the present invention, the three divided winding bodies 11, 12, and 13 are arranged so that the flat laminated portions are in contact with each other. Yes. The ends of the wound bodies 11, 12, and 13 are bent to form three electrode foil laminated portions 10e. And the current collecting plate 21a is welded to each electrode foil lamination | stacking part 10e.

  On the other hand, in FIG. 4 (B) showing the power storage element 100 according to the prior art, a wound body 101 in which the wound bodies 11, 12, and 13 are integrated is disposed. The end portion of the wound body 101 is bent to form a single electrode foil laminated portion 101e. And the current collecting plate 21a is welded to the electrode foil lamination | stacking part 101e.

  Here, the thickness of the electrode of each wound body 11, 12, 13 is in the range of 5 μm to 50 μm, and the number of stacked electrodes of the electrode foil laminated portion 10 e welded to the current collector plate 21 a is in the range of 10 to 40. is there. The electrode thickness of the wound body 101 is the same as the electrode thickness of each of the wound bodies 11, 12, and 13, and the number of electrodes stacked in the electrode foil laminate portion 101 e welded to the current collector plate 21 a is It is approximately three times as large as the foil laminated portion 10e.

  For joining the stacked electrodes to the current collector plate 21a, welding is preferable, and welding methods such as ultrasonic welding, laser welding, and resistance welding are preferably used, and the number of stacked electrodes can be increased by any welding method. By reducing, welding quality improves. This is because, for example, heat conduction is facilitated by reducing the number of stacked electrodes.

  As described above, the electricity storage device according to the present invention can be obtained by appropriately dividing the wound body so that the number of stacked electrodes welded to the current collector plate is in the range of 10 to 40. Thus, reliable joining to the current collector plate becomes possible. Thus, by dividing the wound body into multiple parts, the above-described effects can be obtained, but on the other hand, the number of joints is increased.

  Referring to FIG. 5, in FIG. 5 (A) showing the electricity storage element 10 according to the present invention, the bending length of the electrode foil laminated portion 10e is L1. On the other hand, in FIG. 5B showing the power storage element 100 according to the prior art, the bending length of the electrode foil laminated portion 101e is L2. In FIG. 5, the number of electrodes stacked in the electrode foil stacking portion 101e is approximately twice the number of electrodes stacked in the electrode foil stacking portion 10e. From the above, it is easily understood that L2> L1. And the volume accommodated in a battery can can be increased by dividing | segmenting a wound body.

  Next, the manufacturing method of the electrical storage element by this invention is demonstrated. The manufacturing method of the electrical storage element by this invention includes arrangement | positioning process S1, joining process S2, and bending process S3. In the arranging step S1, the pair of wound bodies 11 and 12 are arranged in parallel at a predetermined distance so that the arc laminated portions 10c and 10d face each other (see FIGS. 3 and 7). In joining process S2, electrode foil lamination | stacking part 10e * 10e and electrode foil lamination | stacking part 10f * 10f arrange | positioned in parallel are welded using a pair of collector plate 210 * 220 formed in strip | belt-plate shape (FIG. 3). And FIG. 7). In the bending step S3, the central portions of the pair of current collector plates 210 and 220 are bent so that the flat laminated portions 10b and 10b come into contact with each other (see FIGS. 1 and 8).

  3 and 7, a pair of current collecting plates 210 and 220 shows the state of the strip before folding, and the pair of current collecting plates 21 and 22 shows the state after folding, It doesn't change. In this specification, the current collector plates 210 and 220 are before folding, and the current collector plates 21 and 22 are bent.

  Since the manufacturing method of the electrical storage element by this invention has joined the strip | belt-shaped collector plate to the negative electrodes and positive electrodes of a pair of winding body mounted on the plane by welding, joining is easy. There is an advantage. As a joining method in joining process S2, welding is preferred and ultrasonic welding, laser welding, and resistance welding can be considered. In these welding methods, the surfaces are overlapped and pressed or heated in the surface direction, so that the joining strength is easily guaranteed. In FIG. 7, in the laser welding method, it is preferable to irradiate a laser on the current collector plate 210 side. In the resistance welding method, it is preferable to devise so as to melt from the current collector plate 210 side.

  In addition, the method for manufacturing a power storage device according to the present invention further includes an external connection terminal mounting step S4 for joining the pair of external connection terminals 2d and 2d to the center of the pair of current collector plates 21 and 22 after the bending step S3. (See FIGS. 1 and 9).

  The method for manufacturing a power storage device according to the present invention further includes an external connection terminal attaching step for joining an external connection terminal to the central portion of the pair of current collector plates after the bending step, so that the current collector plate can be easily bent. Become. This is because no protrusions are provided during the bending process.

  As described above, the power storage device according to the present invention has a current collector by dividing and arranging a pair of electrodes constituting a negative electrode and a positive electrode and a separator wound between these electrodes in a flat shape. The number of stacked electrodes welded to the plate is reduced. The electricity storage device according to the present invention can improve the bonding performance. Moreover, the dead space accommodated in a battery can is reduced by arrange | positioning a winding body separately.

  Practically, it is preferable to divide the winding body so that the number of stacked electrodes to be welded to the current collector plate is in the range of 10 to 40. Reliable joining is possible.

1 is an exploded perspective view showing an embodiment of a power storage device according to the present invention. It is a perspective appearance figure of the winding body which constitutes the electrical storage element by the above-mentioned embodiment, and is a state figure before a pair of electrodes and a separator are wound. FIG. 2 is a perspective external view of the electricity storage device according to the embodiment, and is a state diagram in which a pair of current collecting pieces are joined to a pair of wound bodies. It is a principal part expanded longitudinal cross-sectional view which compared the electrical storage element by this invention with the electrical storage element by a prior art. It is a principal part expanded longitudinal cross-sectional view which compared the electrical storage element by this invention with the electrical storage element by a prior art. It is the figure which compared the electrical storage element by this invention, and the electrical storage element by a prior art, and is a cross-sectional view in the state in which the electrical storage element was accommodated in the battery can. FIG. 7A is a plan view of the power storage element in the joining process, and FIG. 7B is a front view of the power storage element in the joining process. It is a front view which concerns on the manufacturing method of the electrical storage element by this invention, and is a state figure before the electrical storage element after a bending process is accommodated in a battery can. It is a longitudinal cross-sectional view which concerns on the manufacturing method of the electrical storage element by this invention, and is the state figure by which the electrical storage element after the external connection terminal attachment process was accommodated in the battery can. It is a perspective external view which shows the state which attached a pair of plate-shaped member to the winding body of the winding type battery by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a * 1b A pair of electrode 1s Separator 2a * 2b A pair of current collection piece 2c Coupling part 10 Electric power storage element 10a * 10b A pair of flat laminated part 10c * 10d A pair of circular arc laminated part 10e * 10f A pair of electrode foil laminated part 11/12 A pair of wound bodies 21 and 22 A pair of current collector plates

Claims (7)

A pair of electrodes constituting a negative electrode and a positive electrode, a pair of wound bodies in which a separator that insulates these electrodes is laminated and wound in a flat shape, a pair of current collector plates that connect these negative electrodes and positive electrodes, A storage element comprising:
The wound body includes a pair of opposed flat laminated portions, a pair of arc laminated portions opposed to and adjacent to the flat laminated portions, and a pair of extending from the pair of flat laminated portions in opposite directions. An electrode foil laminate, and
The current collector plate has a pair of current collector pieces facing each other, and a coupling portion that couples the base ends of these current collector pieces,
The pair of wound bodies are arranged such that the flat laminated portions are in contact with each other and the electrode foil laminated portions are opposed to each other, and the pair of current collecting pieces are joined to the opposed electrode foil laminated portions. Power storage element.   2. The wound body has a thickness of the electrode in a range of “5” μm to “50” μm, and a number of stacked electrode foil laminates in a range of “10” to “40”. Power storage element.   The power storage device according to claim 1, wherein the current collector plate includes an external connection terminal in the coupling portion.   The electrical storage element in any one of Claim 1 to 3 accommodated in a substantially rectangular parallelepiped box-shaped battery can.   A box-shaped battery can having a substantially rectangular parallelepiped shape that houses a plurality of sets of the power storage elements according to claim 1. A pair of electrodes constituting a negative electrode and a positive electrode, a pair of wound bodies in which a separator that insulates these electrodes is laminated and wound in a flat shape, a pair of current collector plates that connect these negative electrodes and positive electrodes, The wound body includes a pair of opposed flat laminated portions, a pair of arc laminated portions facing each other adjacent to the flat laminated portions, and extending from the pair of flat laminated portions in mutually opposite directions. A pair of electrode foil laminates, and a method of manufacturing an electricity storage device having:
An arrangement step of arranging the pair of wound bodies in parallel so as to be spaced apart from each other by a predetermined distance so that the arc stack portions are opposed to each other;
Using a pair of current collector plates formed in a strip shape, a joining step of welding the electrode foil laminates arranged in parallel,
And a bending step of bending a central portion of the pair of current collector plates so that the flat laminated portions are in contact with each other.   The method for manufacturing an electric storage element according to claim 6, further comprising an external connection terminal attaching step of joining an external connection terminal to a central portion of the pair of current collector plates after the bending step.

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