JP2012060052A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device having excellent low-resistance.SOLUTION: A power storage device at least includes: an element 1 in which sheet-like cathodes 2 and sheet-like anodes 3 are laminated with separators interposed between them and which comprises lead parts 2c and 3c provided at two opposite parts of the cathode 2 and the anode 3, respectively, and each drawing out an electrode; electrolyte impregnated within the element 1; and a first frame 5 and a second frame 8 respectively having a pair of connection parts 5a and 8a which are connected with the pair of leads 2c and 3c respectively. The first frame 5 and the second frame 8 are insulated from each other. The inside surface of the first frame 5 is opposed to the element 1 and a part of the inside surface of the second frame 8 is opposed to the outside surface of the first frame 5. The first frame 5 has a protrusion part at a position opposed to the second frame 8, and the second frame 8 has an open hole, at a position opposed to the first frame 5, in the opposed direction so that the protrusion part is exposed on the outside surface of the second frame 8 through the open hole.

Description

  The present invention relates to a power storage device used for backup power source, regeneration, or power storage 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. 13 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.

  In FIG. 13, the element 100 is composed of strip-shaped positive and negative electrodes, and a separator interposed between the positive and negative electrodes.

  Each of the positive electrode and the negative electrode is formed with lead electrode portions 101 and 102 that are not formed with an electrode portion at one end, and the lead electrode portions 101 and 102 face each other so as to protrude from each other. . The element 100 is formed by winding the positive electrode, the negative electrode, and the separator so that the lead electrode portions 101 and 102 form both ends in the winding axis direction.

  The lead electrode portion 101 of the positive electrode is joined to the metal terminal plate 103 by welding or the like, and the positive electrode is drawn out from the terminal plate 103 to an external circuit.

  The negative electrode lead electrode portion 102 is joined by welding from the inner bottom surface and the outer bottom surface of the bottomed cylindrical metal case 104, and the negative electrode is drawn out from the outer surface of the metal case 104 to an external circuit.

  An insulating tape (not shown) or the like is interposed between the surface of the terminal board 103 and the metal case 104 so that the inner surface does not contact the inner surface.

  By taking out the respective electrodes in this manner, the contact area between the element 100 serving as a lead terminal such as the terminal plate 103 and the metal case 104 and the element 100 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

  Certainly, the conventional power storage device like the electric double layer capacitor reduces the current collecting resistance of the electrode by pulling out each electrode from the electrode non-formed portion such as the lead electrode portions 101 and 102, and By directly bonding the electrode-unformed portion to the bottom surface of the terminal plate or the inner bottom surface of the outer case, the contact area between the element 100, the terminal plate 103, and the outer case 104 has been 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 device whose output characteristics are improved by reducing resistance.

  In order to solve the above-described problems, the power storage device according to the present invention is formed by stacking a separator between a pair of sheet-like electrodes, and is formed at two opposing positions on the outer peripheral surface to draw out the electrode from one electrode. An element having a pair of second electrode lead portions that are formed at two opposing positions on the outer peripheral surface different from those of the first electrode lead portions, and the inside of the element; A first frame having a pair of first connection portions joined to a pair of first electrode lead portions formed in the element, and a second electrode lead portion formed in the element. At least a second frame having a pair of second connecting portions joined to each other, the first frame and the second frame are insulated from each other, the inner surface of the first frame faces the element, and In the second frame A part of the side surface is opposed to the outer surface of the first frame, the first frame has a protruding portion at a position facing the second frame on the outer surface, and the second frame is A through hole in the opposite direction is provided at a location facing the first frame, and the protruding portion is exposed to the outer surface of the second frame through the through hole.

  With this configuration, the power storage device of the present invention can halve the current collecting 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. Accordingly, the connection resistance between each frame and the element can be greatly reduced, and the product characteristics with lower resistance can be developed, and the output characteristics of the power storage device can be enhanced.

1 is an exploded perspective view showing an electric double layer capacitor in Example 1 of the present invention. (A) The perspective view which showed the electric double layer capacitor in Example 1 of this invention, (b) The partial front sectional view which showed an example of the joining method of the 2nd flame | frame used for the electric double layer capacitor, and a case The top view which showed the mode of current collection of one electrode used for the electric double layer capacitor in Example 1 of this invention The exploded perspective view which showed the electric double layer capacitor in Example 2 of this invention (A) The perspective view which showed the electric double layer capacitor in Example 2 of this invention, (b) The partial front view which showed an example of the joining method of the upper surface part of a 2nd frame used for the same electric double layer capacitor, and a connection part Sectional drawing, (c) The partial front sectional view which showed another example of the joining method of the upper surface part of a 2nd frame used for the same electrical double layer capacitor, and a connection part The exploded perspective view which showed the electric double layer capacitor in Example 3 of this invention The perspective view which showed the electric double layer capacitor in Example 3 of this invention The exploded perspective view which showed the electric double layer capacitor in Example 4 of this invention (A) The perspective view which showed the electric double layer capacitor in Example 4 of this invention, (b) The perspective view which showed the structure provided with the terminal part of the electric double layer capacitor Front sectional drawing which extracted and showed the mode of junction with the element used for the electric double layer capacitor in Example 5 of the present invention, and the 1st frame The disassembled perspective view which showed the structure of the element used for the electric double layer capacitor in Example 6 of this invention (A) Top view showing an element used for an electric double layer capacitor in Example 6 of the present invention, (b) Top view showing an element used for an electric double layer capacitor in Example 1 of the present invention Front sectional view showing an electric double layer capacitor as an example of a conventional power storage device (A) The perspective view which showed the element used for the conventional electrical storage apparatus, (b) The exploded view which decomposed | disassembled the element and extracted and showed a part of one electrode foil

  The invention described in Example 1 of the present invention and claims 1, 3, 4, 6, 7, 9, 11, and 12 will be described below with reference to the drawings, but 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 electric double layer capacitor according to a first embodiment of the present invention, FIG. 2 (a) is a perspective view of the electric double layer capacitor, and FIG. 2 (b) is an electric double layer capacitor. It is the partial front sectional view showing an example of the joining method of the 2nd frame and a case.

  In the electric double layer capacitor of this example, a positive electrode 2 and a negative electrode 3 each having a rectangular foil shape are opposed to each other as a pair of electrodes, and a laminate is formed by interposing a separator 4 between the pair of electrodes. A plurality of positive electrodes 2, negative electrodes 3, and separators 4 are prepared, and an element 1 configured by alternately laminating them, an electrolyte solution (not shown) impregnated in the element 1, the element 1 and the electrolyte solution The insulating plate 6 and the O-ring 7 that house and insulate between the first frame 5 and the second frame 8 and the first frame 5 and the second frame 8 that are substantially U-shaped, It is comprised from the bottomed cylindrical case 9 which accommodates a member.

  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 aluminum foil, for example. 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 will be 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.

  Accordingly, the electrode layers 2b and 3b are preferably square in shape.

  The separator 4 constituting the element 1 is not particularly limited as long as it insulates the positive electrode 2 and the negative electrode 3 such as a paper-made material such as cellulose.

  The first frame 5 is made of, for example, a substantially U-shaped aluminum plate, and has a pair of connecting portions 5a facing each other, an upper surface portion 5b serving as a relay portion connecting the pair of connecting portions 5a, and the upper surface portion 5b. The external connection portion 5c is formed and protrudes upward in FIG. The first frame 5 is positioned above the element 1 so that the inner surface of the upper surface portion 5 b faces the element 1 and covers a part of the element 1, and the pair of connection portions 5 a of the first frame 5. Is in contact with and joined to the assembly of the pair of lead portions 2c of the positive electrode 2 of the element 1. That is, in this embodiment, the lead portion 2c corresponds to the first electrode lead portion.

  The insulating plate 6 is disposed on the upper surface portion 5 b of the first frame 5. A through hole 6a that is a through hole is formed in the insulating plate 6 in the thickness direction, and the external connection portion 5c of the first frame 5 is inserted into the through hole 6a, and the external connection portion 5c is connected to the outside from the insulating plate 6 It is configured to be displayed.

  The insulating plate 6 is not particularly limited as long as it is a material that insulates the first frame 5 and the second frame 8 (details will be described later). For example, a sheet made of a rubber-like elastic body made of butyl rubber or ethylene propylene rubber is used. There are a method of interposing, a method of forming an insulating material on at least one of the outer surface of the upper surface portion 5b of each frame and the bottom surface of the upper surface portion 8b in advance to insulate each other. In addition, to the insulating material to be formed, a polyaminoamide compound, a method of applying a modified polyolefin resin, or a solution in which an acrylic-melamine resin is dissolved in a mixed solvent such as water, isopropyl alcohol, petit cellosolve, There is a method of forming by applying a voltage, and a configuration in which an alumite is formed in one of the first frame 5 and the second frame 8 facing each other may be employed. Therefore, the insulating plate 6 is not limited to a plate material as in the name of the member, but may be a layer.

  The second frame 8 is made of, for example, a substantially U-shaped aluminum plate, like the first frame 5, and is an upper surface serving as a relay portion that connects the pair of opposed flat plate-like connection portions 8a and the pair of connection portions 8a. A portion 8b, an exposed hole 8d that is a through hole formed in the thickness direction on the upper surface portion 8b, and an external connection provided on the first frame 5 so as to surround the exposed hole 8d. It is comprised from the external connection part 8c of the 2nd flame | frame 8 which protruded toward the upper surface similarly to the part 5c. Incidentally, as a method of forming the external connection portion 8c, for example, press processing, forging processing, impact processing and the like can be considered.

  The second frame 8 is inserted into the exposed hole 8d so that the external connection portion 5c of the first frame 5 is exposed to the outside of the second frame 8, and the second frame 8 shown in FIG. As described above, the external connection portion 5c is exposed from the opening of the exposed hole 8d. In this case, in this embodiment, the O-ring 7 is interposed between the external connection portion 5c and the exposed hole 8d so that the external connection portion 5c and the inner peripheral surface of the exposed hole 8d are insulated.

  The material constituting the O-ring 7 is not particularly limited as long as it has excellent insulating properties. For example, a peroxide vulcanized rubber such as ethylene propylene rubber or butyl rubber (isobutylene isopropylene rubber), or a resin vulcanized rubber is used. Used. By using these materials, stress relaxation is low as physical properties and moisture permeability is low, so that moisture ingress from the outside to the inside of the power storage device can be suppressed.

  In the present embodiment, the insulating plate 6 and the O-ring 7 are used to insulate the upper surface portion 5b of the first frame 5 and the surface portion of the external connection portion 5c. In the case where is made of butyl rubber or the like, the function of the O-ring 7 may be replaced by the insulating plate 6 by extending a part of the insulating plate 6 to cover the side surface of the external connection portion 5c. As a result, since the O-ring 7 and the insulating plate 6 are configured as an integral member, the interface between the O-ring 7 and the insulating plate 6 is eliminated, the intrusion route of moisture entering from the outside is reduced, and the inside of the power storage device is reduced. Infiltration of moisture can be suppressed.

  An upper surface portion 8 b of the second frame 8 is disposed on the upper surface of the insulating plate 6. And the inner surface of a pair of connection part 8a of the 2nd flame | frame 8 is contact | abutted and joined to the aggregate | assembly of the lead part 3c of the negative electrode 3 which the element 1 has. That is, in the present embodiment, the lead portion 3c corresponds to the second electrode lead portion.

  In addition, the 1st flame | frame 5 and the 2nd flame | frame 8 may be comprised with nickel, iron, copper other than the aluminum plate.

  Moreover, when joining the element 1 and the connection parts 5a and 8a, joining is performed by welding, for example, but at that time, welding is performed so as to form a welding mark so as to be parallel to the stacking direction of the element 1. It is preferable. This can provide many joint points between the positive electrode extraction portion and the negative electrode extraction portion, which are aggregates of the lead portions 2c and 3c, and the connection portions 5a and 8a by one-time welding, thereby improving productivity and reliability. be able to.

  In this embodiment, the element 1, the first frame 5, the insulating plate 6, the O-ring 7, the second frame 8, and these members are accommodated in a bottomed cylindrical case 9.

  In this embodiment, the opening of the case 9 is sealed by the upper surface of the second frame 8.

  When sealing the opening of the case 9, for example, an aluminum material is used for the case 9, and the position where the second frame 8 is disposed from the outer surface of the case 9 is shown in FIG. Welding is performed while forming a welding mark 9e in the direction of the arrow, and the opening of the case 9 is sealed and the second frame 8 is fixed.

  The case 9 may be made of a conductive material such as a metal such as aluminum in consideration of easier welding, but may be made of an insulating material, such as polyphenylene sulfide. It may be a resin or a liquid crystal polymer. In the case where the case 9 is made of a conductive material such as metal, it is preferable that an insulating layer is interposed between the first frame 5 and the second frame 8 at a location facing the inner surface of the case 9. As a method of providing this insulating layer, for example, there is a method of providing a resin tape, an insulating sheet, a resin coat layer or the like between the case 9 and each frame.

  As described above, the power storage device in the present invention taking the electric double layer capacitor of this embodiment as an example is an element in which a positive electrode 2 and a negative electrode 3 each having a pair of lead portions 2c and 3c are stacked with a separator 4 interposed therebetween. 1 and a pair of positive electrode lead portions formed by an assembly of lead portions 2c formed at two opposite positions on the side peripheral surface of the element 1, and two positions facing in a direction orthogonal to the positive electrode lead portion Provided with a pair of negative electrode lead portions formed by an assembly of lead portions 3c formed in the above, and provided with a pair of positive electrode lead portions and a pair of connection portions 5a and 8a respectively joined to the negative electrode lead portions. The first frame 5 and the second frame 8 are at least provided, and the first frame 5 and the second frame 8 are insulated from each other, the inner surface of the first frame 5 faces the element 1, A part of the outer surface of the frame 5 is opposed to a part of the inner surface of the second frame 8, and an external connection is a protruding portion at a position facing the second frame 8 on the outer surface of the first frame 5. The second frame 8 has a through hole at a location facing the first frame 5, and the external connection portion 5 c is exposed to the outer surface of the second frame 8 through the through hole. It is the composition which is.

With the above configuration, the power storage device according to the present invention can draw out electrodes from two locations in each electrode, compared to the conventional configuration in which the positive electrode and the negative electrode are each drawn from one location of the element. In connecting to the first frame 5 and the second frame 8 serving as terminals, the contact area can be increased, and the contact resistance between the element 1 and the first frame 5 and the second frame 8 can be reduced. it can. 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. 3 is an exploded view of the element 1 used in the power storage device of the present invention, showing the joint location in one electrode and the current collection direction in the electrode.

  FIG. 14A is a perspective view showing an element 100 used in a conventional power storage device, and FIG. 14B is an exploded top view showing a joint location in one electrode and a current collecting direction in the electrode. FIG.

  In FIG. 14A, since the conventional element 100 extracts current from both ends in the winding axis direction, the electrode extraction members (not shown) and the electrode extraction members 101 and 102 located at both ends Be joined. In that case, it joins by laser welding etc. so that it may extend in the arrow direction shown by Fig.14 (a). Then, as shown in FIG. 14 (b), a joint location 110 formed by welding is formed. Since the element 100 has a winding shape in the joint portion 110, a portion closer to the winding shaft (not shown) has a small interval between the joint portions 110. 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 joint portions 110 is widened. At this time, as indicated by an arrow shown in FIG. 14B, the current flowing through the electrode requires a path for moving to reach the joint 110 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 110 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 100 has a joint portion 110 located near the outermost periphery of the element 100 no matter how many joint portions are radially increased around the winding axis. It is difficult to reduce the interval.

  Compared with the said structure, as FIG. 3 shows, the positive electrode 2 or the negative electrode 3 used for this invention becomes a structure which has the junction location 10 in a pair of edge part of the lead parts 2c and 3c. Thus, for example, even if the current collector foil of FIG. 14B is formed to have the same width as that of the current collector foil, the current flowing through the electrodes is moved to move to the joints 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 100, the element 1 in the present embodiment rarely increases the interval between the junctions 10 in each of the stacked electrodes, so that the current collection path increases in the interval direction. While being able to suppress, it is easy to narrow the space | interval of each junction location by the increase in the junction location 10. FIG. As described above, the power storage device of the present invention can significantly reduce the current collecting resistance inside the element 1.

  By reducing the resistance of the power storage device in this way, heat generation at the junction between the element 1 and the first frame 5 and the second frame 8 is suppressed, and performance degradation such as carbonization of the separator 4 and decomposition of the electrolytic solution is suppressed. Can be suppressed.

  Further, as described above, by using the first frame 5 and the second frame 8, a total of four electrode lead portions are formed from the positive electrode 2 and the negative electrode 3, and from the element 1 while preventing a short circuit from these electrode lead portions. The electrode can be pulled out. In addition, by housing the element 1, the first frame 5, and the second frame 8 in the case 9, a highly airtight power storage device can be configured.

  Further, the external connection portion 5c is exposed to the outer surface of the second frame 8 through the exposed hole 8d formed in the second frame 8, so that the low resistance as the power storage device is maintained as described above. On the other hand, since the positive electrode 2 and the negative electrode 3 can be connected to a connection member (not shown) such as a bus bar for connecting to an external circuit or the like, a power storage unit is configured by using a plurality of electric double layer capacitors of this embodiment. When connecting to other electronic components or power storage devices, both electrodes can be pulled out from one of them when electrically connecting to other electronic components (not shown) to form an electronic device. (Not shown) can be concentrated and arranged on one side, and the resistance and size of the power storage unit and electronic device can be reduced.

  As a further effect of using both frames, the power storage device of the present invention is different from the conventional power storage device using a wound element, and the external connection portion 5c is exposed by adjusting the hole diameter of the exposure hole 8d. The size of the part can be adjusted freely. Thereby, when drawing out both electrodes from the electrical storage apparatus of this invention, sufficient contact area as an external terminal can be ensured. Thereby, resistance reduction between the external circuit with a connection member etc. and the electrical storage apparatus of this invention can be achieved. Thereby, the resistance of the power storage unit or electronic device using the power storage device of the present invention can be further reduced.

  As shown in FIG. 13, a conventional wound element 100 is used, and a metal case 104 and a terminal plate 103 are joined to both ends of the element 100 in the winding axis direction, and electrodes are drawn out from the element 100. When the power storage device is to reduce the contact resistance with the element 100, the area of the contact surface of the terminal plate 103 with the element 100 needs to be larger than the area of the end calculated from the winding diameter of the element 100. In addition, since the terminal plate 103 also has a function of sealing the opening end portion of the metal case 104, it is necessary to be disposed at the opening end portion of the metal case 104. Therefore, in the conventional power storage device, if one electrode is to be pulled out, one electrode drawn from the metal case 104 needs to be drawn from the opening end of the metal case 104. As described above, there is a limit to the adjustment of the size of the terminal plate 103, and in consideration of the housing efficiency of the element 100 inside the metal case 104 and the space saving as a power storage device, the contact of the opening end of the metal case 104 is possible. This is because it is difficult to increase the area.

  As described above, the present invention has a special effect of being excellent in suppressing the internal resistance of the power storage device and the resistance to the external circuit.

  The element 1 is fixed in the case 9 by interposing an elastic member such as a rubber material between the element 1 and the upper surface portion 5 b of the first frame 5 or between the element 1 and the inner bottom surface of the case 9. The structure which aims at an intensity | strength improvement may be sufficient.

  Further, for example, a configuration may be adopted in which a through hole (not shown) extending to the inside of the case 9 is provided in the external connection portion 5c and a self-returning pressure regulating valve is provided so as to close the opening outside the through hole. Good. However, the formation location of this through hole is not limited to the above.

In addition, in the electrolytic solution used in this example, a solvent using at least one of propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and the like as a solvent, for example, tetraethylammonium tetra Fluoroborate (TEABF ₄ ), triethylmethylammonium tetrafluoroborate (TEMAFF ₄ ), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF ₄ ), 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate use (EDMIBF _4), 1,2,3- trimethyl imidazolium tetrafluoroborate (TMIBF ₄₎ and 1,3-dimethyl-imidazolium tetrafluoroborate (DMIBF ₄₎ at least one of such Although it is Rukoto, 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.

  In addition to the above aluminum foil, the current collectors 2a and 3a are made of titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, silicon, iron, silver, lead, nickel, copper, platinum, gold Alternatively, these alloys may be used. Further, the current collectors 2a and 3a may be plain foils that are not treated, or may be etching foils that have been subjected to etching treatment to increase the adhesive strength with the electrode layers 2b and 3b.

  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, or 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 insulating plate 6 used in this embodiment needs to insulate the first frame 5 and the second frame 8, but it is not necessary to intervene in all locations where the respective frames face each other.

  The main function of the insulating plate 6 is insulation and sealing. In order to satisfy these functions, at least the first frame 5 and the second frame 8 are located at portions facing each other, and the second frame 8 It is preferable that it is located outside the outer shape of the opening of the exposed hole 8d and is formed so as to surround this outer shape. The first and second frames 5 and 8 urge the insulating plate 6 formed as much as necessary in this manner, thereby enabling insulation and sealing. Therefore, in this embodiment, the O-ring 7 has been described as one of the constituent elements. However, the O-ring 7 is not an essential constituent element, and even when not used, the power storage device of the present invention is similarly effective.

  Hereinafter, the second embodiment of the present invention and the invention described in claims 2, 8, and 9 will be described 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.

  4 is an exploded perspective view of the electric double layer capacitor according to the second embodiment of the present invention, FIG. 5A is a perspective view of the electric double layer capacitor, and FIG. 5B is a diagram of the electric double layer capacitor. It is the fragmentary front sectional view which showed an example of the joining method of the upper surface part 18b of the 2nd flame | frame 18, and the connection part 18a, FIG.5 (c) is the joining method of the upper surface part 18b and the connection part 18a of the same electric double layer capacitor. It is a partial front sectional view showing another example.

  In this embodiment, as shown in FIGS. 4 and 5A, the second frame 18 joined to the element 1 while forming the welding mark 18e includes the bottomed rectangular tube-shaped connecting portion 18a and the connecting portion 18a. It is comprised by the upper surface part 18b which is a plate-shaped cover body joined to this opening part and sealing this opening part. And this upper surface part 18b has the exposure hole 18d formed in the thickness direction like the exposure hole 8d of the 2nd flame | frame 8 of Example 1. FIG. Furthermore, like the external connection portion 8c of the first embodiment, the upper surface portion 18b includes an external connection portion 18c that protrudes to the outside and is disposed so as to surround the opening on the outer side of the exposure hole 18d. Similarly, the positive electrode and the negative electrode can be taken out from one side of the electric double layer capacitor to the outside.

  The external connection portion 18c can be formed by using the same method as the external connection portion 5c of the first embodiment. The first frame 5 is substantially U-shaped as in the first embodiment.

  Further, as shown in FIG. 5B, when the upper surface portion 18b and the connection portion 18a are joined, the upper surface portion 18b is placed on the opening end portion of the connection portion 18a, and the edge of the upper surface portion 18b is welded. As shown in FIG. 5 (a), the weld marks 18f are formed, and as shown in FIG. 5 (c), the outer shape of the upper surface portion 18b is smaller than the outer shape of the opening surface of the connecting portion 18a. Further, a notch 18g is formed inside the opening end of the connecting portion 18a, and the upper surface 18b is locked to the notch 18g, and the locked upper surface 18b is shown in FIG. 5 (c). Alternatively, the welding mark 18f may be formed as shown in FIG.

  By joining as shown in FIG. 5B, joining can be performed with less man-hours, so that productivity can be improved. Further, by bonding as shown in FIG. 5C, the positioning of the upper surface portion 18b is facilitated, so that the reliability of bonding as an electric double layer capacitor can be enhanced.

  In the present embodiment, the positive electrode 2 and the negative electrode 3 are drawn from two locations from the element 1, but unlike the first embodiment, the second frame 18 that draws the electrode from the element 1 is formed by the connecting portion 18a and the upper surface portion 18b. By being configured, it also serves as an exterior member that houses the element 1.

  With this configuration, the electric double layer capacitor of the present embodiment can be reduced in resistance as in the first embodiment, and the number of parts is reduced as compared with the first embodiment. Cost reduction and productivity improvement can be achieved.

  Further, when forming the external connection portion 18c, only the upper surface portion 18b, which is a plate material, can be carried and formed, so that productivity can be improved as compared with the power storage device of the first embodiment.

  In the present embodiment, the second frame 18 that also functions to accommodate the element 1 is configured to have one polarity. Accordingly, the outer shape of the upper surface portion 5b of the first frame 5 is a bottomed rectangular tube shape so that the first frame 5 housed in the second frame 18 together with the element 1 does not contact the inner surface of the second frame 18. The second frame 18 needs to be configured to be smaller than the inner shape of the cylindrical portion of the connecting portion 18a. Or the structure which aims at insulation by interposing the member excellent in the insulation in the location which is easy to contact | abut, such as between the connection parts 5a and 18a. As an insulating member to be interposed, when using an electrolytic solution composed of a solvent and a solute, considering the possibility of constant contact with the electrolytic solution, for example, a modified polypropylene having a low reactivity with the electrolytic solution, Examples include polymethylpentene.

  The invention according to the third embodiment and the fifth 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.

  6 is an exploded perspective view of the electric double layer capacitor in Example 3 of the present invention, and FIG. 7 is a perspective view of the electric double layer capacitor.

  In the present embodiment, as shown in FIG. 6, the second frame 28 is constituted by a rectangular tube-shaped connecting portion 28 a and an upper surface portion 28 b so as to cover the upper portion of the connecting portion 28 a, and is a substantially housing having a side surface and a top surface. It is a body-shaped metal member.

  And this upper surface part 28b has the exposed hole 28d formed in the thickness direction like the exposed hole 8d of the 2nd flame | frame 8 of Example 1. FIG. Furthermore, the upper surface portion 28b is provided with an external connection portion 28c protruding outside so as to surround the opening on the outside of the exposed hole 28d. It is possible to take out the positive electrode and the negative electrode.

  The first frame 5 is substantially U-shaped as in the first embodiment.

  In addition, the electric double layer capacitor according to the present embodiment uses a bottom plate 29 having a plate shape to seal the lower opening of the connection portion 28a, and the lower opening end of the second frame 28. It is the composition joined with. With this configuration, the element 1 is accommodated by the second frame 28 and the bottom plate 29.

  The function first required for the bottom plate 29 used in this embodiment is to seal the lower opening of the connecting portion 28a. By using a light material for the bottom plate 29, the weight can be reduced. Considering the bending elastic modulus of the bottom plate 29 and the sealing of the lower opening of the second frame 28, a metal material such as aluminum is preferable.

  When the bottom plate 29 is joined to the second frame 28, the connection portion 28a of the second frame 28 is connected to the upper surface of the bottom plate 29 so that the upper surface portion 18b of the second frame 18 of the second embodiment is connected to the connection portion 18a. A lower end is disposed, and a method of joining the bottom plate 29 and the second frame 28 by welding or the like from the bottom surface side of the bottom plate 29, or an annular notch is formed on the inner side in the thickness direction at the lower end of the cylindrical connection portion 28a. The bottom plate 29 is accommodated in the annular notch so that the bottom surface of the bottom plate 29 and the lower end surface of the connection portion 28a are flush with each other, and is welded from the outer surface side of the connection portion 28a. Since 29 can be easily fixed, it can be stably bonded, and the sealing strength can be improved as an exterior body of the power storage device.

  In this embodiment, the upper surface portion 28b of the second frame 28 is integrated with the connecting portion 28a having a cylindrical shape. However, the upper surface portion 28b is joined to the connecting portion 28a. It may be a thing. In the present embodiment, the upper surface portion 28b is described as being located on the top surface of the second frame 28. However, the present invention is not limited to this, and the upper surface portion 28b is disposed when the power storage device of the present embodiment is disposed. When arranged so as to be located on the lower side, even if the name is the upper surface 28b, it is the bottom surface of the power storage device in the present embodiment.

  Hereinafter, the invention described in Example 4 and claim 10 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. 8 is an exploded perspective view showing the electric double layer capacitor in Example 4 of the present invention.

  As shown in FIG. 8, in this embodiment, the same element 1 as in Embodiment 1 is used, and a pair of connecting portions 35a facing each other as in Embodiment 1 is provided, and these connecting portions 35a are plate-shaped upper surface portions 35b. The first frame 35, which is a U-shaped connection member relayed by the above, is connected to the positive electrode 2 of the element 1, and has a bottomed cylindrical shape and two opposing portions on the inner surface of the cylindrical portion are connected to the connecting portion 38 a. The second frame 38 and the negative electrode 3 of the element 1 are connected.

  Each of the first frame 35 and the second frame 38 connected to the element 1 has an inner surface of the upper surface portion 35b of the first frame 35 and an inner bottom surface of the bottom surface portion 38b of the second frame 38 having a bottomed cylindrical shape. The element 1 is disposed so as to face each other, and the second frame 38 accommodates the element 1 together with the first frame 35. In the second embodiment, as in the second embodiment, the outer surface of the connecting portion 35a and a part of the inner surface of the second frame 38 face each other in the second frame 38. Therefore, it is necessary to interpose an insulating material such as a modified polypropylene particularly at the facing portion as in the second embodiment.

  The first frame 35 is preferably formed with a protruding external connection portion 35c that functions as an external terminal on the outer surface of the upper surface portion 35b in order to increase the degree of freedom in external connection after the power storage device is configured.

  Unlike the first to third embodiments, the external connection portion 35c of the present embodiment does not need to be exposed to the outside from the through hole provided in the second frame, so that at least the apex of the external connection portion 35c is present. It is preferable to be configured to be higher than the apex of the open end of the bottom cylindrical second frame 38. Incidentally, in this embodiment, for example, a flat projection provided on the upper surface portion 35b is configured as the external connection portion 35c.

  FIG. 9A is a perspective view showing an electric double layer capacitor according to the fourth embodiment of the present invention, and FIG. 9B shows the fourth embodiment of the present invention in which the second frame 38 is provided with the external connection portion 38c. It is a perspective view of the electric double layer capacitor in.

  In FIG. 9A, the electric double layer capacitor in the present embodiment includes an upper surface portion 35b of the first frame 35 and a second frame that are exposed from the opening of the second frame 38 in order to constitute one power storage device. A sealing insulating material 37 made of an insulating material such as resin is interposed between the openings of 38 and is fused and sealed.

  Incidentally, with respect to the connection between the connection portions 35a, 38a and the element 1, it is preferable that a welding mark 38e or the like is formed in a direction parallel to the stacking direction of the element 1 as in the other embodiments. In addition, in this Fig.9 (a), illustration of the welding trace formed in the connection part 35a is abbreviate | omitted.

  As described above, the electric double layer capacitor of this embodiment is configured.

  With the above configuration, the electric double layer capacitor in this embodiment can suppress the connection resistance and the current collecting resistance between the element 1 and each frame, as in the other embodiments, and compared with the other embodiments. Since the electric double layer capacitor can be configured with a small number of parts, productivity is improved.

  Further, as shown in FIG. 9B, for example, an external connection portion 38c that is a piece of metal that is integrated with the second frame 38 and is formed by bending one end of the opening of the second frame 38 is provided. It may be a configuration. The external connection portion 38 c is bent and disposed on the upper surface portion 35 b of the first frame 35 via the sealing insulating material 37.

  Thereby, since the external connection portions 35c and 38c are provided in the same direction in the electric double layer capacitor according to the present embodiment, a pair of electrodes can be drawn out from one direction. When a power storage unit is configured by preparing a plurality of electric double layer capacitors, a space required for connection using a bus bar (not shown) or the like can be omitted, so that the power storage unit can be downsized. .

  The invention according to the fifth embodiment and the thirteenth 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. 10 is a front cross-sectional view showing a state before the first frame 5 and the positive electrode 42 used in the electric double layer capacitor in this embodiment abut.

  In the present embodiment, as shown in FIG. 10, the distance between both ends of the current collector 42 a of the positive electrode 42 in the electrode drawing direction (lead portion facing direction) is longer than the distance between the pair of connection portions 5 a of the first frame 5.

  With this configuration, when the inner surface of the connection portion 5a and the lead portion 42c are brought into contact with each other, the current collector 42a in this embodiment does not fit the lead portion 42c, and therefore the lead portions 42c that are in pressure contact with the inner surface of the connection portion 5a. Are bent and overlapped with each other (the swage portion 42d) in contact with the inner surface of the connection portion 5a.

  With this configuration, the electric double layer capacitor according to the present embodiment has the swage portion 42d so as to abut against the end portion of the lead portion 42c while pressing the end portion of the lead portion 42c as compared with the first embodiment in which only the end portion of the lead portion 3c abuts and is joined. By forming the current collector 42a near the end of the lead portion 42c, the current collector 42a is pushed down so as to overlap with each other. As a result, the contact area between the connecting portion 5a of the first frame 5 and the lead portion 42c increases, and the swage portion 42d. Since the current collector 42a is densely packed (the gap between the current collectors 42a is narrowed and the density is high), the current collector 42a can be prevented from being melted by laser welding, and the connection portion 5a of the first frame 5 can be prevented. Opening of holes can be prevented, and the reliability of manufacturing can be improved.

  Further, in order to more easily form the swage portion 42d in the lead portion 42c, a bent portion (not shown) or a notch (not shown) or the like is previously placed on the lead portion 42c, and the second frame 8 or the first frame. 5 or may be obtained by bending the bent portion or the notch to the end of the lead portion 42c preferentially.

  As a method of forming the bent portion in the lead portion 42c, for example, a roller (not shown) or the like is pressed against a desired position of the lead portion 42c to be parallel to the end side of the electrode layer 42b on the lead portion 42c side. There is a method of forming in the direction.

  In addition, as a method of forming the above-mentioned cut in the lead part 42c, for example, by pressing a cutting roller (not shown) at the same time as slitting for forming the end side of the lead part 42c, the electrode layer 42b on the lead part 42c side is pressed. There is a method of forming on the lead part 42c in a direction parallel to the end side.

  In addition, although the present Example demonstrated using the positive electrode 42 and the connection part 5a, it uses the same structure also between the negative electrode 3 in Example 1, and the connection part 8a, and is the reliability of manufacturing similarly. Can be improved.

  The invention according to the sixth embodiment and the fourteenth aspect will be described below with reference to the drawings, but is not limited to the following contents.

  FIG. 11 is an exploded perspective view showing how the element 51 used in the electric double layer capacitor in this embodiment is formed.

  12A is a top sectional view of the element 51, the first frame 55, and the second frame 58 used in the electric double layer capacitor in the present embodiment, and FIG. 12B is an electric double layer capacitor in the first embodiment. It is top surface sectional drawing of the element 1 used for FIG.

  As shown in FIG. 11 and FIG. 12A, the electric double layer capacitor in this example is connected to the lead portions 2c and 3c of the positive electrode 2 and the negative electrode 3 whose ends are constituted by sides in the first example. The lead portions 52c and 53c are formed so that the end portions in contact with the portions 55a and 58a are arcuate.

  Thereby, in contrast to the first embodiment in which the connection portions 5a and 8a are flat, the connection portions 55a and 58a of the present embodiment correspond to the shapes of the lead portions 52c and 53c formed on the positive electrode 52 and the negative electrode 53. It becomes the structure which forms a curved surface. In contrast to the first embodiment in which a block body is formed by the first frame 5, the second frame 8, and the case 9, this embodiment has a first frame 55 and a second frame 58 corresponding to the side surfaces of the electric double layer capacitor. Thus, a power storage device in which a curved surface is formed on at least a part of the connection portions 55a and 58a can be formed.

  In the inner surfaces of these curved surfaces, joint portions electrically connected to the lead portions 52c and 53c are formed as connection portions 55a and 58a. When the power storage device according to the present invention is used for charging and discharging, the joint portion serves as a heat transfer path when heat generated inside the power storage device is transferred from the inside to the outside. This is because the joint portion where the temperature is particularly high in the outer surface of the power storage device can be actively cooled to increase the cooling efficiency.

  As described above, the electric double layer capacitors in the present embodiment in which the connection portions 55a and 58a are curved are arranged in parallel to form a unit, and the connection portions 55a and 58a are used as a side surface to cool using a refrigerant. In the case of performing, when the refrigerant flows in the parallel direction of the electric double layer capacitor of each embodiment, the refrigerant covers the outer periphery of the curved surface according to the curved surfaces of the connecting portions 55a and 58a of the electric double layer capacitor of each embodiment. To pass through.

  In FIG. 12B, when a block type electric double layer capacitor is configured as in the first embodiment or the like, when a unit is configured by arranging a plurality of block type electric double layer capacitors in parallel, volume efficiency is considered. In general, the connecting portions 5a and 8a, which are flat surfaces, face each other and are arranged in parallel so as to be close to each other. Thus, when a unit is comprised by the electric double layer capacitor of a block body, the outer surface of the connection parts 5a and 8a which are not facing the other connection parts 5a and 8a will be cooled preferentially with a refrigerant | coolant. On the other hand, an electric double layer capacitor having a curved surface at the junction with the element 51 as in this embodiment is a block electric double layer capacitor as in the first embodiment as shown in FIG. Compared to the curved surface, the surface area is increased, and it is easy to secure a space for the refrigerant to pass through. Therefore, the cooling performance of the electric double layer capacitor can be improved. Can increase the sex.

  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 according to the present invention is a pair of sheet-like positive electrodes and negative electrodes that are stacked with a separator interposed therebetween and formed at two opposing positions on the outer peripheral surface to draw out the electrodes from the first electrode. A device comprising a first electrode lead-out portion and a pair of second electrode lead-out portions formed at two opposing positions on the outer peripheral surface different from those of the first electrode lead-out portion, and pulling out the electrode from the second electrode, and this element A first frame having at least a pair of first connection portions respectively joined to the pair of first electrode lead portions, and joined to the pair of second electrode lead portions, respectively. And a second frame having a pair of second connection portions, the first frame and the second frame are insulated from each other, and the first frame is disposed so as to cover a part of the element. The second frame is A frame facing portion is formed so as to cover the outer surface of the first frame, and the first and second frames are opposed to each other. In the frame facing portion, a through hole is provided in the second frame. A part of the first frame is exposed from the hole.

  As a result, the contact resistance between the element and the first and second frames that extract the electrodes from the element inside the power storage device can be reduced, and the first and second frames from which the respective electrodes are extracted have the protrusions of the first frame as the first frame. Since the structure is exposed through the through holes provided in the two frames, the first and second frames from which the positive and negative electrodes are drawn can be exposed in the same direction, and can be connected to an external circuit or the like. Since it can be performed in one direction as the power storage device, a space required for connection with the power storage device can be reduced, and a power storage unit or an electronic device using the power storage device of the present invention can be downsized.

  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 the contact area when the electrode is drawn out from the element using the first frame and the second 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, 51 Element 2, 42, 52 Positive electrode 2a, 3a, 42a Current collector 2b, 3b, 42b Electrode layer 2c, 3c, 42c, 52c, 53c Lead part 3, 53 Negative electrode 4 Separator 5, 35, 55 First frame 5a, 8a, 18a, 28a, 35a, 38a, 55a, 58a Connection portion 5b, 8b, 18b, 28b, 35b Upper surface portion 5c, 8c, 18c, 28c, 35c, 38c External connection portion 6 Insulating plate 6a Passing hole 7 O Ring 8, 18, 28, 38, 58 Second frame 8d, 18d, 28d Outgoing hole 9 Case 9e, 18e, 18f, 28e, 38e Weld mark 10 Joint point 18g Notch 29 Bottom plate 37 Sealing insulating material 42d Swage Part

Claims (14)

A pair of first electrode lead portions, which are laminated so that a separator is interposed between a pair of sheet-like electrodes and are formed at two opposing positions on the outer peripheral surface to draw one electrode, and these first electrodes At least an element including a pair of second electrode extraction portions that are formed at two opposing positions on the outer peripheral surface excluding the extraction portion and draw out the other electrode, and an electrolyte contained in the element,
A first frame having a pair of first connection portions respectively joined to the pair of first electrode lead portions, and a first frame having a pair of second connection portions respectively joined to the pair of second electrode lead portions. 2 frames are provided, the first frame and the second frame are insulated from each other, and the first frame is disposed so as to cover a part of the element, and the second frame is disposed outside the first frame. A frame facing portion is formed so as to cover the surface, and the first and second frames are opposed to each other. In the frame facing portion, a through hole is provided in the second frame, and the first frame extends from the through hole. A power storage device that is partly exposed. A pair of first electrode lead portions that are stacked so that a separator is interposed between a pair of sheet-like electrodes and that are formed at two opposing positions on the outer peripheral surface to pull out one electrode, and these first electrode lead portions At least an element including a pair of second electrode extraction portions that are formed at two opposing positions on the outer peripheral surface excluding the portion and draw out the other electrode; and an electrolyte contained in the element;
A first frame having a pair of first connection portions respectively joined to the pair of first electrode lead portions, and a first frame having a pair of second connection portions respectively joined to the pair of second electrode lead portions. Two frames are provided, the first frame and the second frame are insulated from each other, the first frame is disposed so as to cover a part of the element, and the second frame includes the element and the second frame. It is arranged so as to cover a part of the outer surface of one frame,
The second frame has at least a bottom portion and a cylindrical portion, the element is housed in the second frame together with the first frame, and the pair of second connection portions are formed on the inner surface of the cylindrical portion of the second frame. Power storage device. The power storage device according to claim 1, wherein a terminal portion that protrudes to the outside through the through hole is provided in a part of the first frame that is exposed from the through hole of the second frame. Each of the first and second frames is made of a U-shaped metal material in which a pair of connecting portions facing each other by bending both ends of the plane portion is formed, and the plane portion of the first frame is defined as the second frame. The first and second frames are arranged in a state where the connecting portions of the first and second frames are rotated by approximately 90 degrees, and the elements including the electrolyte are accommodated. The power storage device according to claim 1, further comprising a bottomed cylindrical outer case. The said 2nd frame is provided with a cylinder part and a bottom part at least, The said 2nd electrode extraction part is formed in the inner surface of the said cylinder part, The said bottom part forms the said frame opposing part with the said 1st frame. The power storage device described. The power storage device according to claim 5, wherein a lid that seals the second frame is provided at an opening of the cylindrical portion of the second frame. A terminal portion formed on the first frame is defined as a first terminal portion, and a second terminal portion projecting in the same direction as the first terminal portion on the outer surface of the second frame where the through hole is formed. The power storage device according to claim 3, wherein: is formed. A lid that covers the opening of the second frame so that a part of the first frame is exposed; and the lid is made of the same material as the second frame or a material having a specific gravity smaller than that of the second frame. The power storage device according to claim 2. The said 1st frame is a U-shaped metal member comprised from the relay part which connects a pair of opposing part and this opposing part, These pair of opposing parts are said 1st connection parts. Power storage device. The power storage device according to claim 9, wherein a terminal portion formed at an opening end portion of the second frame and bent from the outside to the inside of the second frame is provided. The power storage device according to claim 1, wherein the element is configured by alternately stacking a plurality of the pair of electrodes with the separator interposed therebetween. Each of the pair of electrodes includes a current collector made of a sheet-like metal and an electrode portion formed on the surface of the current collector, and opposite ends of the current collector provided in each of the pair of electrodes A pair of current collector exposed portions formed by the current collector is formed, the pair of current collector exposed portions formed on the one electrode is the first electrode lead portion, and the other electrode The power storage device according to claim 1 or 2, wherein a pair of current collector exposed portions formed on the electrodes are the second electrode lead portions. The power storage device according to claim 12, wherein a facing distance between a pair of connecting portions formed on the first and second frames is smaller than a distance between both ends of the current collector in an electrode drawing direction. The power storage device according to claim 12, wherein an end side of the current collector exposed portion formed on each of the pair of electrodes is in an arc shape.

Images