JP2012059863A - Power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element having excellent low-resistance.SOLUTION: A power storage element includes at least an element 1 in which sheet-like cathodes 2 and sheet-like anodes 3 are laminated with separators 4 interposed between the cathode and the anode and which comprises: lead parts 2c formed at two opposite parts on an outer peripheral surface and each drawing out an electrode from the cathode 2; and lead parts 3c formed at two opposite parts on an outer peripheral surface except for the lead parts 2c and each drawing out an electrode from the anode 3. The separator 4 comprises: a plurality of separating parts 4a interposed between the cathodes 2 and the anodes 3; and relay parts 4b connecting the separating parts 4a to each other. The separator 4 is bent at a part of the relay parts 4b to be alternately folded from the opposite direction so that the separating parts 4a is laminated. At least a part of the relay part 4b is exposed from between the lead part 2c and the lead part 3c adjacent to each other.

Description

  The present invention relates to a power storage element used for backup power source, regeneration, power storage, etc. of various electronic devices, hybrid vehicles and fuel cell vehicles.

  Conventionally, during operation of a device, part of the energy used is energy that is unnecessarily consumed from the device as heat energy or the like. It has been considered that the consumed energy is temporarily stored as electric energy in an electric storage element and reused when necessary, thereby reducing the consumed energy and improving the efficiency.

  At this time, an energy storage element that can extract energy necessary for operation of the device with a necessary output is essential. There are roughly two types of storage element candidates: capacitors and secondary batteries.

  FIG. 10 is a front sectional view showing a method of taking out each electrode of an electric double layer capacitor shown as an example of a conventional capacitor.

  The element 200 includes a strip-shaped positive electrode and negative electrode facing each other, and a separator interposed between the positive electrode and the negative electrode.

  Each of the positive electrode and the negative electrode is formed with lead electrode portions 201 and 202 in which no electrode portion is formed on one end side, and the lead electrode portions 201 and 202 face each other so as to protrude from each other. The lead electrode portions 201 and 202 are each formed by winding the positive electrode, the negative electrode, and the separator so as to form both ends in the winding axis direction.

  The lead electrode portion 201 of the positive electrode is joined to the metal terminal plate 203 by welding or the like, and the positive electrode is drawn out from the terminal plate 203 to an external circuit.

  The negative electrode electrode portion 202 is joined by welding from the inner bottom surface and the outer bottom surface of the bottomed cylindrical metal case 204, and the negative electrode is drawn out from the outer surface of the metal case 204 to an external circuit.

  In addition, an insulating tape (not shown) or the like is interposed between the surface of the terminal plate 203 and the inner surface of the metal case 204 so that they do not come into contact with each other.

  By taking out each electrode in this way, the contact area between the element 200 serving as a lead terminal such as the terminal plate 203 and the metal case 204 and the element 200 can be increased, so that the resistance inside the capacitor is reduced. be able to.

  As prior art document information relating to this application, for example, Patent Document 1 is known.

JP 2007-258414 A

  Like the electric double layer capacitor, the conventional power storage device draws out the respective electrodes from the lead electrode portions 201 and 202 formed on one end side of the current collector of each electrode, and the lead electrode portions 201 and 202 are connected to the terminal plate. By directly bonding to the bottom surface of 203 or the inner bottom surface of the metal case 204, the contact area between the element 200, the terminal plate 203, and the metal case 204 is increased to reduce the resistance.

  However, for power storage devices mounted on electronic devices that require more energy instantaneously, there is a demand not only for lowering the resistance by the configuration of the electric double layer capacitor but also for improving the output density by further lowering the resistance. .

  In view of the above, an object of the present invention is to provide a power storage element used in a power storage device having excellent output characteristics due to low resistance.

  In order to solve the above problems, the power storage device according to the present invention is laminated with a separator interposed between a pair of sheet-like electrodes, and is formed at two opposing positions on the outer peripheral surface to draw out one electrode. And an element having a second electrode lead part formed at two opposing positions on the outer peripheral surface excluding the first electrode lead part and leading out the other electrode, an electrolyte contained in the element, and At least an exterior body that contains an element and an electrolyte, and the separator includes a plurality of separate portions interposed between the pair of electrodes, and a relay portion that connects the separate portions, and the separator includes the relay The bent part is formed in a part of the part, and the separate part is stacked by alternately folding in the opposite direction, and at least a part of the relay part is provided adjacent to each other. It is characterized in that is exposed to the outside through between the first and second electrode lead-out portion.

  With this configuration, the power storage element of the present invention can halve the current collection resistance of the electrode as compared with the conventional method of taking out current from one end of the belt-like electrode body.

  Further, in the case where elements are accommodated as much as possible in the same space which is a cube, a connection area of about 2.55 times can be provided. Therefore, the connection resistance between the connection member and the element can be significantly reduced, and the product characteristics with lower resistance can be expressed, and the output characteristics of the power storage device can be improved.

  Furthermore, in comparison with the manufacturing method in which a plurality of sheet-like separators are laminated one by one, the axis of the separator and the electrode is arranged in order to fold the separator on the laminated electrodes at the time of device fabrication. In particular, the separators are folded in alternating directions by applying uniform stress and tension in the vicinity of the bent part, so that the separation position of the separators in the opposing direction of each electrode varies due to the pressing of the shaft. And the effect of suppressing short circuit in the device is obtained.

  In addition, since the separator is integrally formed, the electrolyte solution impregnation variation in the separate portion can be suppressed by impregnating the electrolyte solution while using the relay portion of the separator.

  In addition, since the separator is folded and stacked so that the relay portion is exposed from the adjacent first and second electrode lead portions as described above, the first and second electrode lead portions overlap with each other. It can be suppressed that the separator is carbonized by being electrically connected to the upper frame, or that the electrical connection is insufficient.

The disassembled perspective view which showed the electrical storage element used for the electric double layer capacitor in Example 1 of this invention (A) is the top view of the electrical storage element used for the electric double layer capacitor in Example 1, (b) is the partial front view which showed the electrical storage element 1 is an exploded perspective view showing an electric double layer capacitor in Example 1 of the present invention. The top view which showed the mode of the current collection of one electrode used for the electric double layer capacitor in Example 1 of this invention The top view which showed the separator used for the electric double layer capacitor in Example 1 of this invention (A) The exploded perspective view which showed the element used for the electric double layer capacitor in Example 2 of this invention, (b) The top view of the element (A)-(g) The assembly top view which showed the lamination | stacking method of the electrode used for the electric double layer capacitor in Example 2 of this invention (A) The exploded perspective view which showed the element used for the electric double layer capacitor in Example 3 of this invention, (b) The top view of the element Partial front sectional view showing a state in which the positive electrode and the upper frame used in the electric double layer capacitor in Example 4 of the present invention are in contact with each other Front sectional view showing a conventional power storage device (A) The perspective view which showed the element used for the conventional electrical storage apparatus, (b) The partial top view which showed the mode of current collection of one electrode used for the element

  Hereinafter, the first embodiment of the present invention and the invention described in claims 1 and 2 will be described with reference to the drawings. However, the present invention is not limited to the following contents.

  In the following description of the power storage device in the present invention, an electric double layer capacitor is used as an example of the power storage device, but the power storage device in the present invention is not limited to the above electric double layer capacitor.

  FIG. 1 is an exploded perspective view of an element 1 used for an electric double layer capacitor in the present embodiment.

  FIG. 2A is a top view of the element 1 used in the electric double layer capacitor in the present embodiment, and FIG. 2B is a partial front view showing the element 1.

  In FIG. 1, an element 1 that is a power storage element used for the electric double layer capacitor of the present example has a positive electrode 2 and a negative electrode 3 that are rectangular foils facing each other as a pair of electrodes, and a separator interposed between the pair of electrodes. The part 4a and the relay part 4b that connects the separate parts 4a are stacked while interposing the strip-shaped separators 4 formed alternately and continuously.

  When the element 1 is manufactured, a plurality of the positive electrodes 2 and the negative electrodes 3 are prepared, and when the separator 4a of the separator 4 is supplied between the positive electrodes 2 and the negative electrodes 3, the left and right or the front and rear are alternately reversed. Folding and laminating, the separation part 4a is just interposed between the positive electrode 2 and the negative electrode 3 facing each other.

  When the separator 4 is folded and stacked, a part of the relay portion 4b is bent, whereby the separator 4 is stacked.

  The positive electrode 2 and the negative electrode 3 are obtained by forming electrode layers 2b and 3b mainly composed of activated carbon on the front and back surfaces of rectangular current collectors 2a and 3a made of, for example, aluminum foil. When the electrode layers 2b and 3b are formed on the current collectors 2a and 3a, respectively, current collectors that do not form the electrode layers 2b and 3b on both ends in the longitudinal direction of the rectangular current collectors 2a and 3a. It forms so that the lead parts 2c and 3c which are body exposed parts may be provided.

  The positive electrode 2 and the negative electrode 3 are opposed to each other so that the longitudinal directions of the positive electrode 2 and the negative electrode 3 that are rectangular are orthogonal to each other, and a plurality of positive electrodes 2, negative electrodes 3, and separators 4 are stacked with a separator 4 interposed therebetween. Element 1 is configured. At this time, since the positive electrode 2 and the negative electrode 3 are arranged so that their longitudinal directions are orthogonal to each other, the lead portions 2c and 3c are exposed to be orthogonal to each other.

  In other words, when the stacking distance of the stacked elements 1 is the height of the element 1, the element 1 used in the electric double layer capacitor of this embodiment forms a substantially cross-shaped column, and the projecting ends of the four sides are respectively It is comprised by the aggregate | assembly of lead part 2c, 3c.

  When the positive electrode 2 and the negative electrode 3 in which the rectangular current collectors 2a and 3a are rectangular in order to form the element 1, the electrode layers 2b and 3b formed on the respective electrodes are used. The shapes are preferably congruent square shapes, and the electrode layer 2b of the positive electrode 2 is preferably opposed to the electrode layer 3b of the negative electrode 3 with little deviation. Furthermore, in the present embodiment, in consideration of a shift in stacking the electrodes, a configuration in which the electrode layer 3b is larger than the area of the electrode layer 2b is preferable. This is because, particularly when the electrolyte anion approaches the electrode layer 2b in charging but the electrode layer 3b is not opposed, the vicinity of the electrode layer 2b becomes acidic, thereby the binder material of the electrode layer 2b and the separator 4 This is because a portion facing the electrode layer 2b may be deteriorated. Since the element 1 is configured such that the lead portions 2c and 3c are exposed in a direction orthogonal to each other, if the electrode layers 2b and 3b are simply formed in the same shape, one electrode is substantially the same as the other electrode. It turns 90 degrees to face each other, and an unopposed portion is often formed in each of the electrode layers 2b and 3b.

  FIG. 3 is an exploded perspective view of the electric double layer capacitor in the present embodiment.

  In FIG. 3, the electric double layer capacitor of this example plays a role of the element 1, an electrolyte solution (not shown) impregnated in the element 1, and an exterior body that accommodates the element 1 and the electrolyte solution, The lower frame 5 and the upper frame 6 are substantially U-shaped.

  The lower frame 5 is composed of, for example, a substantially U-shaped aluminum plate, and is composed of a pair of opposing connection portions 5a and a bottom surface portion 5b that relays the pair of connection portions 5a. The cross-shaped element 1 with respect to the lower frame 5 is disposed on the inner surface of the bottom surface portion 5 b, and the inner surfaces of the pair of connection portions 5 a of the lower frame 5 are connected to the pair of negative electrode lead portions 3 c of the element 1. While contacting the assembly, the assembly of the connecting portion 5a and the lead portion 3c is joined.

  Like the lower frame 5, the upper frame 6 is composed of, for example, a U-shaped aluminum plate, and is composed of a pair of opposed flat plate-like connection portions 6a and an upper surface portion 6b that relays the pair of connection portions 6a. Has been. The upper frame 6 is provided with respect to the element 1 such that the upper surface portion 6b is positioned on the element 1, and the inner surfaces of the pair of connection portions 6a of the upper frame 6 are connected to the positive lead portion 2c of the element 1. While contacting the assembly, the connecting portion 6a and the lead portion 2c are joined.

  The lower frame 5 and the upper frame 6 may be made of nickel, iron, copper, or the like.

  Then, the lower frame 5 and the upper frame 6 are joined and insulated by interposing between the lower frame 5 and the upper frame 6 that are in contact with modified polypropylene as an insulating member (not shown). Insulation, sealing and fixing between the abutting lower frame 5 and upper frame 6 can be considered, for example, by applying heat to the substrate and fusing it, or by applying an epoxy adhesive instead of the modified polypropylene and solidifying it. There is no particular limitation as long as it can be used.

  When the lower frame 5 and the upper frame 6 are joined, in the present embodiment, in order to improve the mechanical strength against an increase in internal pressure due to gas generation during charging / discharging, the connecting portion 5a of the lower frame 5 and the upper frame 6 is used. 6a, a guide groove 6c is formed at a position where the side edge portion of the connection portion 5a abuts on the inner surface of the connection portion 6a, and the side edge portion of the connection portion 5a abuts on the inner surface of the guide groove 6c. The frame 5 slides along the direction in which the guide groove 6c is formed, contacts the upper frame 6, and is fixed with the side end portion of the connecting portion 5a buried in the guide groove 6c.

  Then, as shown in FIG. 3, similarly, a guide groove 5c is formed on the inner surface of the connection portion 5a where the side edge portion of the connection portion 6a abuts, and the connection portion 6a is buried in the guide groove 5c. The side edge part of is fixed.

  With this configuration, compared to a configuration in which the lower frame 5 and the upper frame 6 are simply fixed with an insulating member interposed therebetween, the connection portions 5a and 6a are fixed by the grooves formed of metal, so that the mechanical strength is particularly high. improves.

  In addition, as shown in FIG. 3, in this embodiment, a through hole 6d is formed on the upper surface portion 6b of the upper frame 6 at a position where the connecting portion 5a abuts, and the through hole 6d is formed at the end portion of the connecting portion 5a. A protrusion 5d for fitting into the through hole 6d is formed at a position corresponding to the above, and the lower frame 5 and the upper frame 6 are joined by inserting and fitting the protrusion 5d into the through hole 6d. In addition, the mechanical strength can be further increased.

  In order to bring the guide grooves 5c and 6c and the through hole 6d into contact with the connecting portions 5a and 6a, it is naturally necessary to interpose the insulating member as described above. In order to perform the above-described insulation, an elastic body having an insulating property such as rubber is provided in advance as an insulating member in the guide grooves 5c and 6c and the through hole 6d, and the connection portions 5a and 6a are crimped. Good.

  When the element 1 and the lower frame 5 or the upper frame 6 are joined, a welding mark (shown in the figure) is perpendicular to the edge direction of the foil of the lead portions 2c and 3c constituting the element 1 on the outer surface of the connection portions 5a and 6a. None) is preferably formed.

  This is because almost all electrode foils and joints can be formed by one-time welding, and productivity is increased in producing the power storage device of the present invention. In this embodiment, a self-returning pressure regulating valve (not shown) is provided on the upper frame 6 in order to remove gas generated due to decomposition of the electrolyte in the element 1. In the case where an electrolytic solution is used as in this embodiment, the pressure regulating valve is a housing chamber (not shown) that houses the element 1 formed by the lower frame 5 and the upper frame 6 after the lower frame 5 and the upper frame 6 are joined. ) In the lower frame 5 or the upper frame 6 and an injection hole (not shown) for the electrolyte to be injected into the inside of the inside of the inside is provided so as to seal the injection hole. It is preferable from the fact that it can be reduced.

  Further, in consideration of the fact that the electrolyte also flows through the inside of the accommodation chamber, the injection hole is located at a position where the element 1 is not opposed or a position where the element 1 is not in contact with the lower frame 5 and the upper frame 6. Preferably it is formed.

  This is because the electrolytic solution can be injected more smoothly by intentionally opening a space near the injection hole in the storage chamber.

  With this configuration, the electrolytic solution can be impregnated more deeply into the element 1 and productivity can be improved.

  In this way, the electrodes drawn out from the positive electrode 2 and the negative electrode 3 are drawn out from the lead portions 2c and 3c corresponding to the opposite end portions of the respective current collectors 2a and 3a, and the lead portions 2c and 3c are exposed so as not to be short-circuited. By forming each element 1 by making the directions orthogonal to each other and pulling out each electrode by the lower frame 5 and the upper frame 6 provided with the connecting portions 5a and 6a connected to the respective lead portions 2c and 3c, a limited volume is obtained. The contact area between the element 1 and the lower frame 5 and the upper frame 6 serving as external terminals can be increased, and the resistance between the element 1 and the lower frame 5 and the upper frame 6 can be reduced as a power storage device. be able to.

This is because if a device is accommodated so as to be inscribed in a space of the same volume having a cubic shape with the length of one side being r, a conventional spiral-shaped device (approximate connection) that takes out current from the one end side. area: compared with π × r ^2/4), the element 1 of the present invention (approximately connection area: r ² × 2) is a it is possible to obtain the connection area of about 2.55 times the one of the electrodes .

  Furthermore, as compared with the conventional element, the element 1 of the present invention can halve the current collecting resistance of each electrode. The reason will be described in detail below.

  FIG. 4 is a plan view of the element 1 used in the power storage device of the present invention, disassembled and showing the joint location in one electrode and the current collection direction in the electrode.

  FIG. 11A is a perspective view showing an element 200 used in a conventional power storage device, and FIG. 11B is a partial plan view showing a state of current collection of one electrode used in the element.

  In FIG. 11A, the conventional element 200 takes out current from both ends in the winding axis direction. Therefore, in the extraction electrode portions 201 and 202 positioned at both ends, the electrode extraction member (not shown) and Be joined. In that case, it joins by laser welding etc. so that it may extend in the arrow direction shown by Fig.11 (a). Then, as shown in FIG. 11 (b), a joint location 210 formed by welding is formed. Since the element 200 has a winding shape in the joint portion 210, a portion closer to the winding shaft (not shown) has a small interval between the joint portions 210. However, in the portion far from the winding axis, the diameter of the substantially circular ring formed by the current collector end portion is increased at the same time, so that the interval between the joining portions 210 is widened. At this time, as indicated by an arrow shown in FIG. 11 (b), the current flowing in the electrode requires a path for moving to reach the junction 210 at least the distance W of the width of the current collector foil. In addition, it is necessary to move the portion where the interval between the joints 210 is wide by the distance D of the interval. Further, in particular, the portion corresponding to the vicinity of the outermost periphery of the wound element 200 has an interval between the joints 210 located near the outermost periphery of the element 200, no matter how many joints are radially increased around the winding axis. It is difficult to narrow down.

  Compared to the above configuration, as shown in FIG. 4, the positive electrode 2 or the negative electrode 3 used in the present invention has a configuration in which a joint portion 10 is provided at a pair of end portions of the lead portions 2 c and 3 c. Thus, for example, even if the current collector foil of the electrode in FIG. 11B is formed to have the same width as the current collector foil, the current flowing inside the electrode is moved to move to the joint 10 formed at both ends of each electrode. The current collection path is about half as shown by the arrow. In addition, unlike the above-described wound element 200, the element 1 in the present embodiment rarely widens the gap between the joints 10 in each stacked electrode, so that the current collection path increases in the gap direction. While being able to suppress, it is easy to narrow the space | interval of each joining location by the joining location 10 increase. As described above, the power storage device of the present invention can significantly reduce the current collecting resistance inside the element 1.

  From the above, output characteristics can be improved as the power storage device.

  In addition, by reducing the resistance, heat generation at the junction between the element 1 and the lower frame 5 and the upper frame 6 can be suppressed, and performance degradation such as carbonization of the separator 4 and decomposition of the electrolytic solution can be suppressed. .

  Further, in the present embodiment, in order to fold the separator on the stacked electrodes at the time of manufacturing the element, for example, using a pressing means such as a rod-shaped shaft, the separator and the pair of electrodes are uniform, particularly in the vicinity of the bent portion. The separators are folded in alternate directions while applying appropriate pressure and tension. At this time, the shaft is arranged and used so that its longitudinal direction is substantially parallel to the folding line of the folding portion. Compared with the manufacturing method in which a plurality of sheet-like separators are laminated one by one due to the stress and tension applied from this shaft, the arrangement position of the separation part 4a is less likely to vary in each facing direction, There are effects such as short circuit suppression. Furthermore, the straight line accuracy of the folding line is also improved.

  The shape of the shaft is not limited to a rod shape as described above, and may be a plate shape.

  This is because, as shown in FIGS. 1 and 2B, when the separators 4 are stacked while being alternately folded, for example, the separators 4 are stacked while being tensioned using a shaft in order to be folded. However, the parallelism of the separator 4 is increased by the tension at this time. This is because the parallelism of the element 1 is increased, the misalignment during the lamination of the other positive electrode 2 and negative electrode 3 is also suppressed, and the possibility of non-opposing portions between the electrode layers 2b and 3b can be reduced.

  Further, as shown in FIGS. 2 (a) and 2 (b), by using the separator 4 as described above, the separator 4 can be formed integrally, so that the electrolytic solution is impregnated while using the relay portion 4b or the like. By doing so, variation in impregnation of each separate portion 4a is suppressed.

  When the element 1 is configured so that the relay part 4b is exposed from the adjacent positive electrode extraction part and negative electrode extraction part as described above, the element 1 is configured using the integral separator 4, and the positive electrode extraction is performed. It can be suppressed that the separator 4 is carbonized or overlapped with the electrically connected portions of the lead portions 2c and 3c corresponding to the portion or the negative electrode lead-out portion, or the electrical connection becomes insufficient.

  Moreover, in the element which pulls out one electrode from the two opposing positions as in the present invention, the configuration of the separator 4 of the present invention has a remarkable effect.

  This is because when the electrolyte is injected from above in the stacking direction of the element 1, the electrolyte entering the exterior case such as the lower frame 5 and the upper frame 6 is formed by the lead portions 2c and 3c adjacent to the inner surface of the exterior case. It penetrates toward the bottom of the element 1 through the gap. Therefore, by configuring the element 1 so that the relay portion 4b of the separator 4 is exposed from the element 1 as in the present invention in the gap that is the infiltration path of the electrolyte solution, the electrolyte solution is actively supplied from the relay portion 4b. In the element 1 that is impregnated and drawn out from two opposing positions as in the present invention, the separator 4 has improved electrolyte impregnation.

  FIG. 5 is a top view showing the separator 4 used in the electric double layer capacitor of this embodiment.

  In this embodiment, as shown in FIG. 5, the separator 4 has, for example, a substantially rectangular separate portion 4a, a relay portion 4b connected to one end of the separate portion 4a, and another end connected to the relay portion 4b. A separate unit 4a and a relay unit 4b are alternately connected, such as a separate unit 4a. The shape of the separate portion 4a is not particularly limited to the above.

  The separator 4 is not particularly limited as long as the separator 4 insulates the positive electrode 2 and the negative electrode 3 such as a paper material such as cellulose.

  In addition to the activated carbon as described above, the electrode layers 2b and 3b contain a conductive agent such as an ammonium salt of carboxymethyl cellulose, a binder such as polytetrafluoroethylene, and acetylene black, thereby reducing the distance between the activated carbons. In addition, since the electrical conductivity can be improved, the resistance of the element 1 can be further reduced.

  The invention according to the second embodiment and the third aspect of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following contents. Further, the same components as those in the first embodiment will be described with the same reference numerals as those in the first embodiment.

  FIG. 6A is an exploded perspective view showing the configuration of the element 11 used in the electric double layer capacitor described in this embodiment, and FIG. 6B is a top view of the element.

  In FIG. 6A, the element 11 used in the electric double layer capacitor of the present example is formed by laminating the positive electrode 12 and the negative electrode 13 each having a band shape alternately. The separator 4a of the separator 4 according to the first embodiment is interposed between the stacked positive electrode 12 and negative electrode 13.

  In the positive electrode 12 and the negative electrode 13, electrode layers 12b and 13b are formed on the front and back surfaces of current collectors 12a and 13a made of a strip-shaped aluminum foil, respectively. The electrode layers 12b and 13b are formed using means such as intermittent coating, for example, except for a portion that is bent when the positive electrode 12 and the negative electrode 13 are folded.

  FIGS. 7A to 7G are assembly top views sequentially showing the stacking method of the elements 11 in this embodiment.

  When the element 11 is formed, the belt-like positive electrode 12, the negative electrode 13, and the separator 4 to be folded are folded in different directions. The folding directions of the positive electrode 12 and the negative electrode 13 are orthogonal to each other, and the separator 4 is folded in a direction different from the folding direction of the positive electrode 12 and the negative electrode 13. For example, first, as shown in FIG. 7 (a), the separate part 4a located at one end of the separator 4 and the electrode layer forming part located at one end of one electrode are overlapped to face each other, as shown in FIG. 7 (b). In addition, the separator 4 is folded and the separate portion 4a is stacked on one electrode, and the electrode layer forming portion located at one end of the other electrode is stacked on the separate portion 4a so as to face each other. 7 (c), the separator 4 stacks the separation portion 4a on the other electrode, and the next electrode layer forming portion of the one electrode is folded so as to face the separation portion 4a. As in (d) to (g), the respective members are alternately folded in the respective directions in the order of the separator 4, the other electrode, the separator 4, the one electrode, and the separator 4, and finally FIG. b) Continue to form the device 11 such as.

  When the element 11 is manufactured, the electrode layer non-formed portions of the bent electrode layers 12b and 13b become lead portions 12c and 13c protruding in the cross direction, respectively. Electrodes are drawn out from the element 11 as the positive electrode extraction portion and the negative electrode extraction portion, particularly using the end sides of the lead portions 12c and 13c. Therefore, when forming the electrode layer non-formed portion, it is preferable that the width is not less than twice the length to be projected as the lead portion.

  The electric double layer capacitor in this embodiment is configured by accommodating the element 11 by a lower frame 5 and an upper frame 6 which are exterior bodies.

  Also in this embodiment, as in the first embodiment, the relay portion 4b of the separator 4 is exposed from between the protruding lead portions 12c and 13c.

  According to this configuration, since each electrode can be drawn out from two locations as in the first embodiment, the resistance can be reduced and the impregnation of the electrolyte in the separator 4 can be improved.

  In addition, by laminating not only the separator 4 but also the positive electrode 12 and the negative electrode 13 alternately, the positive electrode 2 and the negative electrode 3 are laminated as compared with a configuration in which a plurality of foil-like positive electrodes 2 and negative electrodes 3 are laminated. Thus, the effect of improving the charge / discharge balance is reduced because each electrode has less non-opposing portions with the other electrode.

  When manufacturing the element 11, the manufacturing apparatus to be used includes a positive electrode supply unit, a negative electrode supply unit, a separator supply unit, an element placement unit on which stacked members are placed, and a member supplied from each supply unit. Each of the supply parts is supplied from three directions toward the element placement part based on the element placement part, and is efficiently provided. Each member can be folded.

  The invention according to the third embodiment and the fourth aspect of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following contents. Further, the same components as those in the first embodiment will be described with the same reference numerals as those in the first and second embodiments.

  FIG. 8A is an exploded perspective view showing an element 21 used in an electric double layer capacitor as an example of the power storage device in the present embodiment, and FIG. 8B is a top view of the element.

  The positive electrode 12 and the negative electrode 13 used in the element 21 of this example are the same as those used in Example 2.

  As shown in FIG. 8 (a), in the present embodiment, a plurality of positive electrodes 12 and 13 that are opposed to each other and alternately folded and stacked are disposed so that at least one of each electrode is interposed between the positive electrodes 12 and 13. An element is configured using a sheet-like separator 24.

  Since the element 21 is configured in this manner, the positive electrode 12 and the negative electrode 13 are configured using the integrated current collectors 12a and 13a as in the second embodiment. When stacking layers, there is less misalignment in stacking than a configuration in which a plurality of sheet-like electrodes are stacked. Therefore, the effect of short circuit suppression can be enhanced.

  Hereinafter, the invention described in Example 4 and claims 5 and 6 of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following contents. Further, the same components as those in the first embodiment will be described with the same reference numerals as those in the first embodiment.

  FIG. 9 is a partial front sectional view showing a state before the upper frame 6 and the positive electrode 32 used in the electric double layer capacitor in this embodiment are in contact with each other.

  In this embodiment, as shown in FIG. 9, the distance between the lead portions 32 c provided at both ends of the current collector 32 a of the positive electrode 32 is longer than the distance between the pair of connection portions 6 a of the upper frame 6.

  With this configuration, when the inner surface of the connection portion 6a and the lead portion 32c are brought into contact with each other, the current collector 32a in this embodiment does not fit the lead portion 32c, and therefore the lead portions 32c that are in pressure contact with the inner surface of the connection portion 6a. Is configured to be in contact with the inner surface of the connecting portion 6a in a state of being bent and overlapped (swage portion 32d).

  With this configuration, the electric double layer capacitor in this embodiment has the swage portion 32d so as to abut against the end portion of the lead portion 32c while pressing the end portion of the lead portion 32c, as compared with the first embodiment in which only the end portion of the lead portion 3c abuts and is joined. As a result, the current collector 32a near the end of the lead portion 32c is pushed down so as to overlap, and as a result, the contact area between the connection portion 6a of the frame 6 and the lead portion 32c becomes large, and the swage portion 32d Since the current collector 32a is densely packed (the gap between the current collectors 32a is narrowed and the density is high), the current collector 32a is prevented from being melted by laser welding, and the connection portion 6a of the upper frame 6 has holes. Opening can be prevented and the reliability of manufacturing can be improved.

  Further, in order to more easily form the swage portion 32d in the lead portion 32c, a bent portion (not shown) or a notch (not shown) is previously placed on the lead portion 32c, and the upper frame 6 or the lower frame 5 is formed. It may be obtained by sliding insertion, or may be preferentially bent from the bent portion or notch to the end of the lead portion 32c.

  As a method of forming the bent portion in the lead portion 32c, for example, a roller (not shown) or the like is pressed against a desired position of the lead portion 32c to thereby end the electrode layer 32b on the lead portion 32c side. There is a method of forming in a direction parallel to the side.

  In addition, as a method of forming the above-mentioned cut in the lead part 32c, for example, an electrode layer on the lead part 32c side is pressed by pressing a cut roller (not shown) at the same time as slit processing for forming the end side of the lead part 32c. There is a method of forming on the lead part 32c in a direction parallel to the end side of 32b.

  In addition, although the present Example demonstrated using the positive electrode 32 and the connection part 6a, it uses the same structure also between the negative electrode 3 in Example 1, and the connection part 5a, and is the reliability of manufacturing similarly. Can be improved. Similarly, the lead portions 12c and 13c of the element 11 in the second embodiment are formed by bending a part of the current collectors 12a and 13a, but a swage portion as in the present embodiment is formed. Can do.

  In addition, although the lower frame 5 and the upper frame 6 which were demonstrated as a component in the said Examples 1-3 were the substantially U-shaped metal members provided with a pair of connection parts 5a and 6a, it is limited to this structure. As long as it has a configuration in which at least a pair of connection portions are provided for the configuration in which each electrode is drawn out from both ends in two directions of the element 1 and the electrodes drawn out from two locations are collectively drawn to an external circuit Thus, the special effect of the present invention, that is, lowering the resistance of the power storage device, is achieved.

  Accordingly, one of the lower frame 5 and the upper frame 6 may be a bottomed case-like metal member, and the lower frame 5 and the upper frame 6 are used only as external terminals to accommodate the element 1 and the electrolyte. You may provide separately exterior bodies, such as resin or a metal member.

  In particular, it is preferable that one of the upper frame 5 and the lower frame 6 constitutes the electric double layer capacitor of the present invention by using a metal bottom case to improve the airtightness of the device.

  However, when adopting these configurations, it is necessary to sufficiently insulate so that the lower frame 5 and the upper frame 6 do not directly contact each other.

Incidentally, in the electrolytic solution used in this example, the solvent used is at least one of propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), etc. Fluoroborate (TEABF ₄ ), triethylmethylammonium tetrafluoroborate (TEMAFF ₄ ), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF ₄ ), 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate (EDMIBF _4), 1,2,3- trimethyl imidazolium tetrafluoroborate (TMIBF ₄₎ and 1,3-dimethyl-imidazolium tetrafluoroborate (DMIBF ₄₎ at least one of such You can have, but is not particularly limited solvent, an electrolyte.

  As described above, the present invention is not limited to use as an electrolytic solution, and a configuration in which a binder is included in a solvent and a gel-like one or a solid electrolyte is used may be used.

  Further, the material used for the current collectors 2a and 3a is not limited to aluminum as described above, and titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, silicon, iron, silver, lead, Nickel, copper, platinum, gold, or an alloy thereof may be used. The current collectors 2a and 3a may be untreated plain foils, or may be etched foils that have been subjected to etching treatment to increase the adhesive strength with the electrode layers 2b and 3b.

  In addition to the carbon material such as activated carbon as described above, the electrode layers 2b and 3b include activated carbon that includes a binder such as ammonium salt of carboxymethyl cellulose and polytetrafluoroethylene, and a conductive agent such as acetylene black. Since the distance between the electrodes can be shortened and the conductivity can be improved, the element 1 can have a lower resistance.

  The present invention is not limited to an electric double layer capacitor. Lithium ions are used as an electrolyte cation, lithium is occluded in the carbon material contained in the negative electrode layer, and the positive electrode is an electric double layer capacitor. Even when applied to an electrochemical capacitor that charges and discharges using a positive electrode, and similarly to a storage battery that mainly uses a metal member as a current collecting member for each electrode layer such as a lithium secondary battery. As a power storage device, it is possible to achieve a special effect of realizing low resistance.

  As described above, the power storage device of the present invention is laminated with a separator interposed between a sheet-like positive electrode and a negative electrode, and is formed at two opposing positions on the outer peripheral surface to draw out the electrode from the positive electrode, An element having a negative electrode extraction part that is formed at two opposite positions on the outer peripheral surface excluding the positive electrode extraction part and draws an electrode from the negative electrode, an electrolyte contained in the element, and the element and the electrolyte are accommodated At least an exterior body, and the separator includes a plurality of separate portions interposed between the positive electrode and the negative electrode, and a relay portion connecting the separate portions, and the separator is bent at a part of the relay portion. Before the separate portions are stacked, and at least part of the relay portions are provided adjacent to each other. It is exposed to the composed between the positive electrode lead-out portion negative electrode lead-out portion.

  With this configuration, each of the elements in a limited space can be obtained by pulling out electrodes drawn from one of the conventional electrode foils from two places by the lower frame and the upper frame having the pair of connection portions. The contact area between the lower frame and the upper frame, which play the role of the pair of electrode lead portions and the external terminals, can be increased, and the resistance of the power storage device can be reduced. Furthermore, compared to a manufacturing method in which a plurality of sheet-like separators are laminated one by one, the separators are laminated while being folded in alternate directions at the time of element production. The separation position of the separate portion is less likely to vary, and effects such as short circuit suppression in the element can be obtained.

  In addition, since the separator is integrally formed, the electrolyte solution impregnation variation in the separate portion can be suppressed by impregnating the electrolyte solution while using the relay portion of the separator.

  In addition, since the separator is folded and laminated so that the relay portion is exposed from the adjacent first and second electrode lead portions as described above, the lower frame overlaps with the first and second electrode lead portions. It is possible to prevent the separator from carbonizing due to electrical connection with the upper frame, or insufficient electrical connection.

  The power storage device according to the present invention includes a first frame and a second frame each having an element that pulls out each electrode from opposite ends of each sheet-like electrode, and a pair of connection portions that draw the electrode from the sheet-like electrode. At least a frame is provided, whereby a contact area when an electrode is drawn out from the element using the lower frame and the upper frame is increased, and a reduction in resistance is achieved.

  Therefore, the power storage device according to the present invention is expected to be used in a mobile body such as an electronic device or an electric vehicle that needs to extract more power in a short time.

1, 11, 21 Element 2, 12, 32 Positive electrode 2a, 3a, 12a, 13a, 32a Current collector 2b, 3b, 12b, 13b, 32b Electrode layer 2c, 3c, 12c, 13c, 32c Lead part 3, 13 Negative electrode 4, 24 Separator 4a Separate part 4b Relay part 5 Lower frame 5a, 6a Connection part 5b Bottom face part 5c, 6c Guide groove 5d Projection part 6 Upper frame 6b Upper surface part 6d Through hole 32d Swage part

Claims (6)

A pair of sheet-like electrodes are stacked with a separator interposed therebetween, and are formed at two opposing positions on the outer peripheral surface to draw out one electrode, and an outer periphery excluding the first electrode leading portion A second electrode lead portion that is formed at two opposite sides of the surface and pulls out the other electrode;
The separator is composed of a plurality of separate parts interposed between the positive electrode and the negative electrode, and a relay part connecting the separate parts,
The separator has a bent part formed in a part of the relay part, and is alternately folded in the opposite direction to stack the separate part, and at least a part of the relay part is provided adjacent to the separator part. A power storage element exposed from between the first electrode lead portion and the second electrode lead portion. At least one of the pair of electrodes is composed of a rectangular foil-shaped current collector and an electrode layer formed on at least one surface of the current collector, and a plurality of the pair of electrodes interpose the separator The electrode layers are formed so as to have electrode layer unformed portions on a pair of opposite sides of the current collector, and the electrode layer unformed portions of the pair of electrodes are the first electrode portions. The power storage device according to claim 1, which is an electrode lead portion and the second electrode lead portion. The pair of electrodes includes a sheet-like current collector, and electrode layers formed so as to have electrode layer non-formed portions at regular intervals in the longitudinal direction on both surfaces of the current collector, and the electrode non-formed portions And the pair of electrodes are alternately folded and stacked so that the electrode layers face each other while interposing a separator of the separator, and the bent portions of the pair of electrodes are the first electrodes. The electricity storage device according to claim 1, wherein the electricity storage element is a lead portion and the second electrode lead portion, and the pair of electrodes have different folding directions. At least a device comprising a pair of electrodes facing each other and a separator interposed therebetween,
The pair of electrodes is composed of a sheet-like current collector and an electrode layer formed on the surface of the current collector and having an intermittent portion where the current collector is exposed at regular intervals. And the pair of electrodes are alternately folded and stacked so that the electrode layers face each other with the separator interposed therebetween, and the respective bent portions of the pair of electrodes are the first electrode lead-out portions. And the second electrode lead-out portion, and the pair of electrodes have different folding directions. The electric storage element according to claim 2, wherein a plurality of electrode layer unformed portions provided on the pair of electrodes are bent in one direction to be folded. 5. The power storage device according to claim 3, wherein a plurality of bent portions each formed by an intermittent portion provided on each of the pair of electrodes are bent in one direction to form a folded portion.

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