JP2014072348A - Electrochemical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical device capable of responding to a high voltage and also being thinned.SOLUTION: An electrochemical device comprises: a first element 10; a second element 20; an outer sheet 4 covering the first element and the second element; and a partition sheet 30 laminated between the first element and the second element inside the outer sheet, for partitioning between a first electrolytic solution and a second electrolytic solution. The device further includes seal portions 40-44 in which a peripheral portion of the outer sheet 4 integrally sandwiches a peripheral portion of the partition sheet 30. In the first seal portion 40, first lead terminals 18 and 19 and second lead terminals 28 and 29 are led out to the outside of the seal portion 40 at different positions along a longitudinal direction of the first seal portion 40.

Description

  The present invention relates to an electrochemical device that is preferably used as an electric double layer capacitor or the like, and more particularly to an electrochemical device that can be made thinner.

  Electrochemical devices such as electric double layer capacitors are constructed with material limitations so that they can withstand voltages higher than electrolysis by connecting several single cells in series to handle high voltages. Techniques to supplement with design are taken. Needless to say, a single cell has a pair of lead terminals and is connected in series by connecting one lead terminals of a plurality of single cells.

  Originally, since the single cell has drawn out the lead terminal to the outside of the exterior body, the connecting portion is connected outside the exterior body. One method is to overlap the lead terminals to be connected to a plurality of single cells, and then to weld them, causing an increase in thickness due to the overlapping of the lead terminals. Usually, when overlapping the lead terminals, In many cases, a resin for bonding is formed and heat-sealed, which leads to a further increase in thickness. An increase in thickness is not preferable because it may cause deterioration of the sealing performance of the outer package.

  On the other hand, the thickness of the terminal also affects the strength of the terminal, which may cause problems in terminal bonding during mounting. It is difficult to meet the requirements at the same time. In recent years, lithium batteries and the like are often used in the field of IC cards and the like, and their application to electric double layer capacitors is also being studied. At this time, the thickness of the battery product in the IC card is required to be very thin, for example, 0.9 mm or less.

  As an electrochemical device used in an IC card or the like, for example, a device shown in Patent Document 1 shown below is known. However, the device shown in Patent Document 1 is a single cell, and it is necessary to connect several single cells in series in order to cope with a high voltage. For example, when a single cell as shown in Patent Document 1 is simply laminated, the exterior sheet becomes double, and the total thickness increases accordingly.

JP 2011-151171 A

  The present invention has been made in view of such a situation, and an object thereof is to provide an electrochemical device that can be made thin while being able to cope with a high voltage.

In order to achieve the above object, an electrochemical device according to the present invention comprises:
A first element in which a pair of first internal electrodes are stacked so as to sandwich the first separator layer;
A second element in which a pair of second internal electrodes are laminated so as to sandwich the second separator layer;
An exterior sheet covering at least the first element and the second element;
A partition sheet that is laminated between the first element and the second element inside the exterior sheet and separates the first electrolyte solution and the second electrolyte solution;
A first lead terminal connected to at least one first internal electrode of the pair of first internal electrodes;
An electrochemical device having a second lead terminal connected to at least one second internal electrode of the pair of second internal electrodes,
A seal part that is integrated so that a peripheral part of the exterior sheet sandwiches a peripheral part of the partition sheet;
In the seal portion, the first lead terminal and the second lead terminal are drawn out of the seal portion at different positions along the longitudinal direction of the seal portion.

  In the electrochemical device according to the present invention, two or more elements partitioned by the partition sheet can be accommodated in the exterior sheet. Therefore, it can cope with a high voltage. Moreover, since two or more elements are stacked via the partition sheet, it contributes to miniaturization of the device as compared with the case where two or more elements are arranged in the horizontal direction.

  Furthermore, in the electrochemical device according to the present invention, the first lead terminal of the first element and the second lead terminal of the second element are drawn out of the seal portion at different positions along the longitudinal direction of the seal portion. Yes. For this reason, it is possible to reduce the thickness of the seal part in the lead-out part of the lead terminal. The thickness of the battery product in the IC card is required to be very thin, for example, 0.9 mm or less, and the problem with the thinning of the electrochemical device is the thickness of the seal portion at the lead terminal lead-out portion. . Although the thickness of each member which comprises an electrochemical device can be made thin, since a seal | sticker part becomes the total thickness of a some member, it is a part which tends to cause a relative thickness increase. For this reason, conventionally, it has been difficult to relatively reduce the thickness of the seal portion in the lead-out portion of the lead terminal. However, the present invention makes it possible to reduce the thickness for the first time. In particular, in the present invention, a thickness of 0.9 mm or less can be achieved while stacking two or more cells.

Preferably, the electrochemical device according to the present invention comprises
A pair of first lead terminals connected to each of the pair of first internal electrodes;
A pair of second lead terminals connected to each of the pair of second internal electrodes,
These four lead terminals are drawn out to the outside of the seal portion at different positions all along the longitudinal direction of the seal portion.

  In the electrochemical device according to the present invention, the first internal electrode and the second internal electrode which are adjacent to each other in the stacking direction via the partition sheet may be connected inside the exterior sheet, but the seal portion via the lead terminal It is preferable to be connected outside. Compared to the case where the first internal electrode and the second internal electrode are connected inside the exterior sheet, there is no thickness addition by the exterior sheet when the connection is made outside the seal portion via the lead terminal. Can contribute to the reduction in thickness. Therefore, at least four lead terminals are pulled out to the outside of the seal portion at positions that are all different along the longitudinal direction of the seal portion, thereby further reducing the thickness of the device.

  Preferably, one of the pair of first lead terminals and one of the pair of second lead terminals are adjacent to each other along the longitudinal direction of the seal portion, and outside the seal portion. Are electrically connected. With this configuration, it is easy to connect the first element and the second element in series, the withstand voltage of the device can be increased corresponding to the number of elements, and the device can be further thinned. Can be realized. In addition, the wiring resistance between the terminals can be reduced to the minimum. The connection portion thus connected may be used as a terminal for controlling the voltage by connecting to a balance circuit or the like. If necessary, one of the pair of first lead terminals and one of the pair of second lead terminals are connected so that the first element and the second element are connected in parallel. You may connect.

  Preferably, a part of the seal part has a first seal part (top seal part) for pulling out a lead terminal, and the first lead terminal and the second lead terminal are long in the first seal part. It is pulled out of the first seal portion at different positions along the direction.

  Preferably, the first seal portion includes a sealing tape that sandwiches the first lead terminal and the second lead terminal, together with a peripheral portion on the first seal portion side of the partition sheet, and a first portion of the exterior sheet. It is formed by being sandwiched between the peripheral portions on the seal portion side and thermally sealed. By heat-sealing, the sealing tape and the peripheral edge portion on the first seal portion side of the partition sheet are integrated with heat, and the lead terminal take-out portion has good sealing inside the exterior sheet. In addition, the thickness of the first seal portion can be reduced to the minimum while maintaining good sealing.

Preferably, both ends of the first seal portion in the longitudinal direction are continuously formed so that one end of a third seal portion (side seal portion) is connected to each other, and the other end of these third seal portions The second seal part (bottom seal part) is formed continuously,
The third seal part is formed by heat sealing a part of the peripheral edge of the partition sheet sandwiched between the exterior sheets,
The second seal part is formed by heat sealing the other part of the peripheral edge of the partition sheet by being sandwiched by folding the exterior sheet.

  With this configuration, the first electrolyte solution of the first element and the second electrolyte solution of the second element are separated from each other inside the exterior sheet while keeping the thickness of the device thin, and these It is possible to effectively prevent the solution from leaking outside the exterior sheet.

  Preferably, there is further provided a support sheet for preventing the first lead terminal and the second lead terminal pulled out from the first seal portion from being bent. By comprising in this way, the bending of the 1st lead terminal and 2nd lead terminal withdraw | derived from the 1st seal | sticker part can be prevented effectively.

  Preferably, the support sheet is formed by extending one of peripheral edges on the first seal portion side of the exterior sheet located in the first seal portion to the outside. By comprising in this way, formation of a support sheet becomes easy.

  Preferably, the protruding length of the support sheet is longer than the protruding lengths of the first lead terminal and the second lead terminal. By comprising in this way, the bending of the 1st lead terminal and 2nd lead terminal withdraw | derived from the 1st seal | sticker part can be prevented effectively.

1A is a perspective view of an electric double layer capacitor according to an embodiment of the present invention, and FIG. 1B is a perspective view of an electric double layer capacitor according to another embodiment of the present invention. 2A is a schematic cross-sectional view taken along line IIA-IIA in FIG. 1A. 2B is a schematic cross-sectional view taken along the line IIB-IIB in FIG. 1B. FIG. 3 is a schematic perspective view showing an example of a manufacturing method of the electric double layer capacitor shown in FIG. FIG. 4A is a perspective view showing a continuation process of FIG. 4B is a schematic cross-sectional view taken along line IVB-IVB in FIG. 4A. FIG. 5 is a perspective view showing a step subsequent to FIG. FIG. 6 is a perspective view showing a step subsequent to FIG. FIG. 7 is a perspective view showing a step subsequent to FIG. FIG. 8 is a perspective view showing a step subsequent to FIG. FIG. 9 is a perspective view showing a step subsequent to FIG. FIG. 10 is a perspective view showing a step subsequent to FIG. FIG. 11 is a perspective view showing a step subsequent to FIG. FIG. 12 is a perspective view showing a step subsequent to FIG. FIG. 13 is a perspective view showing a step subsequent to FIG. FIG. 14 is a perspective view of an electric double layer capacitor according to another embodiment of the present invention. FIG. 15 is an exploded perspective view of an electric double layer capacitor according to still another embodiment of the present invention.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
First Embodiment As shown in FIG. 1A, an electric double layer capacitor (EDLC) 2 as an electrochemical device according to an embodiment of the present invention has an exterior sheet 4. The exterior sheet 4 has a front surface 4a and a back surface 4b formed by folding a single sheet 4 around the peripheral edge 4c.

  In the present embodiment, the exterior sheet 4 has a rectangular shape in which the length W0 in the Y-axis direction is longer than the length L0 in the X-axis direction, but is not limited thereto, and may be a square, other polygonal shapes, or It may be circular, elliptical, or other shapes. In this embodiment, the direction in which the front surface 4a and the back surface 4b of the exterior sheet 4 overlap is the thickness direction (Z-axis direction), and the directions orthogonal to each other are the X-axis and Y-axis.

  As will be described later with reference to FIG. 2A, the exterior sheet 4 is laminated at a position where the first element 10 and the second element 20 overlap each other. A pair of first lead terminals 18 and 19 and a pair of second lead terminals 28 and 29 drawn out from the elements 10 and 20 are drawn out of the exterior sheet 4.

  As shown in FIG. 1A, in the present embodiment, the interior of the rectangular exterior sheet 4 includes a first seal part 40, a third seal part 42, and a second seal part formed along the four sides of the exterior sheet 4. 44 and is sealed. In this embodiment, the side from which the lead terminals 18, 19, 28, 29 are pulled out in the X-axis direction is referred to as a first seal portion (top seal portion), and a peripheral portion 4c formed by folding an exterior sheet on the opposite side. The side is referred to as a second seal portion (bottom seal portion). A method of forming these seal portions 40, 42 and 44 will be described later.

  As shown in FIG. 2A, the first element 10 and the second element 20 are stacked in the Z-axis direction through the partition sheet 30 inside the exterior sheet 4. The first element 10 and the second element 20 have the same configuration, and as described later, only the take-out positions of the lead terminals 18, 18 and 28, 29 are different. The first element 10 and the second element 20 each constitute an element of an electric double layer capacitor. In the present embodiment, two capacitor elements are accommodated in the exterior sheet 4.

  As shown in FIG. 4B, the first element 10 has a pair of first internal electrodes 16 and 17 laminated so as to sandwich the first separator layer 11 infiltrated with the first electrolyte solution. One of the first internal electrodes 16 and 17 is a positive electrode and the other is a negative electrode, but the configuration is the same. The first internal electrodes 16 and 17 are in contact with the first active layers 12 and 14 and the first active layers 12 and 14, respectively, which are stacked so as to be in contact with the opposite surfaces of the first separator layer 11. Thus, the first current collector layers 13 and 15 are laminated.

  The second element 20 is the same as the first element 10, and as shown in FIG. 2A, a pair of second internal electrodes 26 and 27 are laminated so as to sandwich the second separator layer 21 infiltrated with the second electrolyte solution. It is. One of the second internal electrodes 26 and 27 is a positive electrode and the other is a negative electrode, but the configuration is the same. The second internal electrodes 16 and 27 are in contact with the second active layers 22 and 24, which are stacked so as to be in contact with the opposite surfaces of the second separator layer 21, and the second active layers 22 and 24, respectively. Thus, the second current collector layers 23 and 25 are laminated.

  The separator layer 11 (21) is configured to electrically insulate the internal electrodes 16 and 17 (26 and 27), respectively, and to be able to permeate the electrolyte solution. For example, the separator layer 11 (21) includes an electrically insulating porous sheet. . The electrically insulating porous sheet is at least selected from the group consisting of monolayers and laminates of films made of polyethylene, polypropylene or polyolefin, stretched films of the above-mentioned resin mixtures, or cellulose, polyester and polypropylene. Examples thereof include a fiber nonwoven fabric made of one kind of constituent material. The thickness of the separator layer 11 (21) is, for example, about 5 to 50 μm.

  The current collector layers 13, 15, 23, and 25 are not particularly limited as long as they are generally highly conductive materials, but metal materials having low electrical resistance are preferably used. For example, copper, aluminum, nickel, etc. Such a sheet is used. The thickness of each of these current collector layers 13, 15, 23, 25 is, for example, about 15 to 50 μm.

  The active layers 12, 14, 22, and 24 include an active material and a binder, and preferably include a conductive aid. The active layers 12, 14, 22, 24 are formed by being laminated on the surface of the sheet constituting each of the current collector layers 13, 15, 23, 25.

  Examples of the active material include porous bodies having various electronic conductivities, such as natural graphite, artificial graphite, mesocarbon microbeads, mesocarbon fibers (MCF), cokes, glassy carbon, and organic compound fired bodies. The carbon material is mentioned. The binder is not particularly limited as long as the above active material, preferably the conductive auxiliary agent, can be fixed to the sheet constituting the current collector layer, and various binders can be used. Examples of the binder include fluorine resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR) and water-soluble polymers (carboxymethylcellulose, polyvinyl alcohol, sodium polyacrylate, Dextrin, gluten, etc.) and the like.

  The conductive assistant is a material added to increase the electronic conductivity of the active layers 12, 14, 22, 24. Examples of the conductive aid include carbon materials such as carbon black and acetylene black, fine metal powders such as copper, nickel, stainless steel, and iron, a mixture of carbon materials and fine metal powders, and conductive oxides such as ITO.

  The thickness of the active layers 12, 14, 22, and 24 is preferably about 1 to 200 μm, for example. The active layers 12, 14, 22, 24 are formed on the current collector layers 13, 15, 23, 25 so as to avoid the portion where the lead terminals are connected. The active layers 12, 14, 22, and 24 can be manufactured by a known method.

  In the present embodiment, the “positive electrode” is an electrode that adsorbs anions in the electrolyte solution when a voltage is applied to the electric double layer capacitor, and the “negative electrode” is a voltage applied to the electric double layer capacitor. In this case, the electrode adsorbs cations in the electrolyte solution. In addition, when recharging after applying a voltage to the electric double layer capacitor once in a specific positive / negative direction, charging is usually performed in the same direction as the first and charged by applying a voltage in the opposite direction. There is little to do.

  The partition sheet 30 is preferably made of an electrically insulating material, made of a material that does not allow the electrolyte solution described later contained in each of the two elements 10 and 20 to pass therethrough, and can be heat sealed. For example, the partition sheet 30 is made of polypropylene (PP), polyethersulfone (PES), polyethylene (PE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), fluororesin, polyimide (PI), or the like. Preferably there is. The thickness of the partition sheet 6 is preferably 20 to 100 μm.

  The exterior sheet 4 is preferably made of a material that does not allow permeation of the electrolyte solution described later, and is integrated with the peripheral edge of the partition sheet 30 or the sealing tape 40a shown in FIG. 5 by heat sealing. This sealing tape is preferably in the form of a tape such as an adhesive tape in view of workability. However, not only the tape but also a sealant resin that can be applied may be in any form as long as it can be melted and adhered by heat. The exterior sheet 4 is configured to seal the elements 10 and 20 and prevent air and moisture from entering the sheet 4. Specifically, the exterior sheet 4 may be a single-layer sheet, but as shown in FIG. 2A, the exterior sheet 4 is a multilayer sheet in which the metal sheet 4A is laminated so as to be sandwiched between the inner sheet 4B and the outer sheet 4C. Is preferred.

  The metal sheet 4A is preferably made of, for example, aluminum, stainless steel or the like, and the inner sheet 4B is made of an electrical insulating material, and is a partition sheet such as polypropylene that hardly reacts with the electrolyte solution and can be heat sealed. It is preferable that they are made of the same material. The outer sheet 4C is not particularly limited, and is preferably composed of, for example, PET, PC, PES, PEN, PI, fluororesin, PE, polybutylene terephthalate (PBT), and the like. The thickness of the exterior sheet 4 is preferably 5 to 50 μm.

  The lead terminals 18, 19, 28, and 29 are conductive members that function as current input / output terminals for the current collector layers 13, 15, 23, and 25, and have a rectangular plate shape. The thickness of the lead terminals 18, 19, 28, 29 is preferably about 20 to 1000 μm.

  The space surrounded by the exterior sheet 4 and separated by the partition sheet 30 and sealing each element 10 and 20 by the seal portions 40, 42 and 44 is filled with an electrolyte solution (not shown). The part is impregnated inside the electrodes 16, 17, 26, 27 and the separator layers 11 and 21.

As the electrolyte solution, a solution in which an electrolyte is dissolved in an organic solvent is used. Examples of the electrolyte include quaternary ammonium salts such as tetraethylammonium tetrafluoroborate (TEA ⁺ BF4 ⁻ ) and triethylmonomethylammonium tetrafluoroborate (TEMA ⁺ BF4 ⁻ ), ammonium salts, amine salts, and amidine salts. Is preferred. In addition, these electrolytes may be used individually by 1 type, and may use 2 or more types together.

  Moreover, a well-known solvent can be used as an organic solvent. Preferred examples of the organic solvent include propylene carbonate, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, γ-butyrolactone, dimethylformamide, sulfolane, acetonitrile, propionitrile, and methoxyacetonitrile. These may be used alone or in combination of two or more at any ratio.

  The first electrolyte solution accommodated in the space for the first element 10 and the second electrolyte solution accommodated in the space for the second element 20 may be the same or different, but are the same. Is preferred. This is because manufacturing becomes easy. The first electrolyte solution and the second electrolyte solution are separated from each other by the partition sheet 30 and the seal portions 40, 42, and 44.

  In the present embodiment, the end portions of the current collector layers 13, 15, 23, 25 of the internal electrodes 16, 17, 26, 27 on the first seal portion 40 side are the current collector layers 12, 14, 22, 24. The rear ends of the thin plate-like lead terminals 18, 19, 28, 29 are connected to the inside of the end portions by ultrasonic welding, spot welding or the like. The position where the rear end of each lead terminal 18, 19, 28, 29 is connected to the end of each current collector layer 13, 15, 23, 25 differs in the Z-axis direction as shown in FIG. The axial direction is also different.

  As shown in FIG. 2A, the tips of the lead terminals 18, 19, 28, and 29 penetrate the first seal portion 40 and are drawn out of the first seal portion 40. The first seal portion 40 is a portion from which the lead terminals 18, 19, 28, and 29 are pulled out. The first seal portion 40 is particularly required to have a sealing performance as compared with the third seal portion 42 and the second seal portion 44. The thickness T0 is the thickest part among the parts of the EDLC2. In the present embodiment, by adopting a method described later, the thickness T0 of this portion is reduced to 0.9 mm or less, and a suitable sealing performance is successfully maintained.

  As shown in FIG. 1, in the present embodiment, in the first seal portion 40, the first lead terminals 18 and 19 and the second lead terminals 28 and 29 are in the longitudinal direction (Y-axis direction) of the first seal portion 40. Are pulled out to the outside of the first seal portion 40 at different positions. Moreover, one of the pair of first lead terminals 18 and 19 and one of the pair of second lead terminals 28 and 29 are adjacent to each other with a gap W3 along the longitudinal direction of the first seal portion 40. In addition, outside the first seal portion 40, it is electrically connected by the connection piece 50.

  The connection piece 50 is made of the same material as the lead terminals 18, 19, 28, 29 and has the same thickness. The connection between the two lead terminals 19 and 28 adjacent to each other by the connection piece 50 can be performed by a method similar to the connection between the lead terminal and the current collector layer described above, such as ultrasonic welding.

  In the present embodiment, the gap W3 between the two adjacent lead terminals 19 and 28 is narrower than the gap W4 between the second lead terminals 28 and 29 (the gap between the first lead terminals 18 and 19 is the same), Preferably, it is 0.2 mm or more. If the gap W3 is too narrow, the sealant resin may not easily enter the gap W3 portion of the first seal portion 40, and the thickness of the first seal portion 40 may increase under high temperature and high humidity. is there. If the gap W3 is too wide, the gap W4 between the second lead terminals 28 and 29 (the gap between the first lead terminals 18 and 19 is the same) when the width of the EDLC 2 in the Y-axis direction does not change. It becomes relatively narrow, which is not preferable in terms of terminal handling during mounting.

  The widths W1 and W2 in the Y-axis direction of the second lead terminals 28 and 29 (the same applies to the first lead terminals 18 and 19) may be different. In that case, the relationship of W1 <W2 is preferable for the purpose of reducing the wiring resistance connecting the elements. On the other hand, when it is desired to take out a high voltage instantaneously from the EDLC, the relationship of W1> W2 is preferable because the take-out resistance becomes low. Specifically, the width W1 is preferably 1 to 4 mm, for example. Further, when the EDLC 2 is accommodated in the IC card, the width W0 in the Y-axis direction is preferably 10 to 50 mm, and the length L0 in the X-axis direction is preferably 10 to 50 mm.

  In the present embodiment, the first lead terminal 18 (second lead terminal 29) located outside the pair of first lead terminals 18 and 19 (also the second lead terminals 28 and 29) is located inside. The first lead terminal 19 (second lead terminal 29) is formed so as to protrude in the X-axis direction.

  That is, as shown in FIG. 2A, the protruding length L1 from the first seal portion 40 of the first lead terminal 18 (second lead terminal 29) located on the outer side is the first lead terminal 19 (first number) located on the inner side. It is longer than the protruding length L2 of the 2-lead terminal 29). The protruding length L2 is preferably 3 to 10 mm, and L1-L2 is preferably 1 to 3 mm. By setting L1> L2, it is possible to prevent mishandling of terminals. Further, leakage from the connection piece 50 can be prevented, and a more reliable electrochemical device can be provided.

  In the present embodiment, the first seal portion 40 that is most likely to leak in the past is integrated with the peripheral edge of the partition sheet 30 by heating at the time of heat sealing with the sealing tape 40a shown in FIG. 5, as will be described later. To be formed. At that time, the inner sheet 4B formed on the inner peripheral surface of the exterior sheet 4 is also integrated, and the sealing performance at the first seal portion is improved. Further, since the peripheral edge portion of the partition sheet 30 is integrated with the first seal portion 40, the separation between the space for accommodating the first element 10 and the space for accommodating the second element 20 is maintained well.

  Further, in the second seal portion 44, the bottom side peripheral portion of the partition sheet 30 is sandwiched by being folded at the folded peripheral portion 4c of the exterior sheet 4, and the bottom side peripheral portion of the partition sheet 30 is heated by heat at the time of heat sealing. The outer sheet 4 is integrated with the inner sheet 4B. As a result, the sealing performance at the second seal portion 44 is ensured, and the space for housing the first element 10 and the space for housing the second element 20 are also maintained well.

  In the 3rd seal part 42 shown in Drawing 1 (A), the bottom side peripheral part of partition sheet 30 is inserted by each side peripheral part 4e in surface 4a and back 4b of exterior sheet 4, and by the heat at the time of heat sealing, The bottom edge of the partition sheet 30 is integrated with the inner sheet 4 </ b> B of the exterior sheet 4. As a result, the sealing performance at the third seal portion 42 is ensured, and the space for accommodating the first element 10 and the space for accommodating the second element 20 are also maintained well.

  At both ends in the longitudinal direction of the first seal portion 40, one end of the third seal portion 42 is continuously formed, and the other end of these third seal portions 42 is connected. A second seal portion 44 is formed continuously. Therefore, the inside of the exterior sheet 4 is satisfactorily sealed with respect to the exterior of the exterior sheet 4 while being separated in the Z-axis direction by the partition sheet 30.

  In the EDLC 2 of the present embodiment, two or more elements 10 and 20 partitioned by the partition sheet 30 can be accommodated in the exterior sheet 4. Therefore, it can cope with a high voltage. Moreover, since the two or more elements 10 and 20 are stacked via the partition sheet 30, it contributes to the miniaturization of the device as compared with the case where two or more elements are arranged in the horizontal direction.

  Further, in the EDLC 2 of the present embodiment, the first lead terminals 18 and 19 of the first element 10 and the second lead terminals 28 and 29 of the second element 20 are connected in the longitudinal direction (Z It is pulled out of the seal portion 40 at different positions along the axial direction. For this reason, it is possible to reduce the thickness in the Z-axis direction of the seal portion 40 in the lead portions of the lead terminals 18, 19, 28, and 29.

  The thickness of the battery product in the IC card is required to be very thin, for example, 0.9 mm or less, and the problem with the thinning of the EDLC is the seal at the lead-out portions of the lead terminals 18, 19, 28, 29. This is the thickness of the portion 40. That is, even though the other portions can be made thin, it has been difficult to reduce the thickness of the seal portion 40 in the lead portions of the lead terminals 18, 19, 28, and 29 to 0.9 mm or less. Became possible for the first time. That is, in the present embodiment, a thickness of 0.9 mm or less (more preferably 0.6 mm or less, particularly preferably 0.5 mm or less) can be realized while stacking two or more cells.

  In the EDLC 2 of the present embodiment, the first internal electrode 17 and the second internal electrode 26 that are adjacent to each other in the stacking direction via the partition sheet 30 are connected to the connection piece outside the seal portion 40 via the lead terminals 19 and 28. 50 is connected. The connecting piece 50 is installed in the vicinity of the seal portion 40. In other words, the connection piece 50 is disposed in the vicinity of the side of the exterior body sheet in the present embodiment. By doing in this way, it becomes EDLC corresponding to the high withstand voltage by which the 1st element and the 2nd element were integrated electrically. Compared with the case where the first internal electrode 17 and the second internal electrode 26 are connected inside the exterior sheet 4, it is thinner to connect the device outside the seal portion 40 via the lead terminals 19 and 28. Can contribute to

  The EDLC 2 of this embodiment finally uses the first lead terminal 18 as a positive electrode and the second lead terminal 29 as a negative electrode, whereby the elements 10 and 20 from which the electrolyte solution is separated are connected in series, and the withstand voltage is reduced. improves. In ELDC, the withstand voltage of a single element is determined to be about 2.85 V at maximum, and it is effective to connect the elements in series in order to improve the withstand voltage according to the application. Since the ELDC of this embodiment is extremely thin and has a sufficient withstand voltage, it can be suitably used as a battery for incorporation in a thin electronic component such as an IC card.

  As shown in FIG. 1A, in the present embodiment, one terminal 19 of the pair of first lead terminals 18 and 19 and one terminal 28 of the pair of second lead terminals 28 and 29 Are adjacent to each other along the longitudinal direction of the seal portion 40 and are electrically connected to each other outside the seal portion 40. With this configuration, it is easy to connect the first element 10 and the second element 20 shown in FIG. 2A in series, and the withstand voltage of the device can be increased corresponding to the number of elements. At the same time, the device can be made thinner. The connection portion thus connected may be connected to a balance circuit or the like. In addition, you may comprise so that the 1st element 10 and the 2nd element 20 may be connected in parallel as needed.

  Next, an example of a method for manufacturing the EDLC 2 of the present embodiment will be described with reference to FIGS.

  As shown in FIGS. 3, 4A, and 4B, first, the first element 10 is manufactured. In order to manufacture the 1st element 10, as shown in FIG. 3, the 1st internal electrodes 16 and 17 are arrange | positioned on the surface and back surface of the 1st separator layer 11. As shown in FIG. As shown in detail in FIG. 4B, the rear ends of the first lead terminals 18 and 19 are superposed inside the ends of the current collector layers 13 and 15 of the internal electrodes 16 and 17 on the first seal portion side, respectively. Connected by sonic welding. Internal electrodes 16 and 17 are laminated on both sides of the separator layer 11 so that the active layers 12 and 14 are in contact with each other. As shown in FIGS. 4A and 4B, the laminated body constituting the first element 10 is temporarily fixed by a tape 46.

  A sealing tape 40a is bonded to each lead terminal 18 and 19 at a position in the X-axis direction that becomes the above-described first seal portion 40 so as to sandwich the terminals 18 and 19 therebetween. The terminals 18 and 19 are spaced apart at a predetermined interval (width W4 shown in FIG. 1) in the Y-axis direction, and the width of the tape 40a in the Y-axis direction is a tape that is bonded to the terminals 18 and 19. The width is preferably such that the 40a does not contact each other.

  Specifically, the width of the tape 40a in the Y-axis direction is preferably 0.5 to 3 mm longer than W1. If the width of the tape 40a in the Y-axis direction is too narrow, the sealing performance in the first seal portion 40 shown in FIG. 2A may not be sufficient, and if the width is too wide, the tapes overlap and the thickness of the first seal portion. T0 becomes large, which is not preferable.

  The width of the tape 40a in the X-axis direction corresponds to the length L3 of the first seal portion 40 shown in FIG. 2A in the X-axis direction, and is preferably 2 to 4 mm.

  Next, as shown in FIG. 5, the second element 20 is formed in the same manner as the first element 10, and the first element 10 and the second element 20 are arranged so as to sandwich the partition sheet 30. Since the gap between the lead terminals 19 and 28 (gap W3 shown in FIG. 1A) is small, the tapes 40a bonded to the lead terminals 19 and 28 overlap each other in the Y-axis direction. . However, since the gap between the lead terminals 19 and 28 (the gap W3 shown in FIG. 1A) is appropriately maintained, the first seal portion 40 formed after heat sealing described in a later step is used. Sealing performance is not reduced.

  Next, as shown in FIG. 6, the exterior sheet 4 is folded at the peripheral edge 4 c so as to cover the entire elements 10 and 20 arranged so as to sandwich the partition sheet 30, and the front surface 4 a and the back surface 4 b of the sheet are folded. The elements 10 and 20 are covered.

  The exterior sheet 4 and the partition sheet 30 are previously formed long in the Y-axis direction. The width of the exterior sheet 4 and the partition sheet 30 in the X-axis direction is adjusted so that the peripheral edge 4d on the first seal portion side of the exterior sheet 4 and the peripheral edge of the partition sheet 30 overlap with the tape 40a.

  Next, as shown in FIG. 7, the exterior sheet 4 that covers the entire elements 10 and 20 arranged so as to sandwich the partition sheet 30 is set on the jig 60, and the folded peripheral edge 4 c of the exterior sheet 4 is added. The second seal portion 44 is formed by pressure heating.

  Next, as shown in FIG. 8, the peripheral edge 4 d on the first seal part side of the exterior sheet is pressurized and heated to form the first seal part 40. At that time, the peripheral edge portion of the partition sheet 30 is formed integrally with the sealing tape 40a by heating at the time of heat sealing. At that time, the inner sheet 4B (see FIG. 2A) formed on the inner peripheral surface of the exterior sheet 4 is also integrated, and the sealing performance at the first seal portion 40 is improved.

  Next, as shown in FIG. 9, the third seal portion 42 only on one side is formed by the same heat seal as described above, and then the third seal portion 42 is not formed as shown in FIG. The electrolyte solution is injected from the opening end 62 of the exterior sheet 4, and then, as shown in FIG. 11, the final third seal portion 42 is formed by the same heat seal as described above.

  Next, as shown in FIG. 12, the exterior sheet 4 is cut along with the partition sheet 30 along the cutting line 64 outside the third seal portion 42, and the excess exterior sheet 4 ′ is removed. Finally, as shown in FIG. 13, the EDLC 2 of the present embodiment is obtained by connecting the adjacent first lead terminal 19 and the second lead terminal 28 with a connecting piece 50.

  In the manufacturing method according to the present embodiment, the first sealing portion 40 includes an exterior sheet that includes a sealing tape 40 a sandwiching the first lead terminals 18 and 19 and the second lead terminals 28 and 29 together with the peripheral edge portion of the partition sheet 30. 4 is formed by being sandwiched between the peripheral portions 4d on the first seal portion side and heat-sealed. By heat-sealing, the sealing tape 40a and the peripheral portion of the partition sheet 30 are integrated by heat, and the inside of the exterior sheet 4 is well sealed at the lead-out portions of the lead terminals 18, 19, 28, 29. . In addition, the thickness of the first seal portion 40 can be reduced to a minimum while maintaining good sealing.

  With this configuration, the first electrolyte solution of the first element 10 and the second electrolyte solution of the second element 20 are separated from each other inside the exterior sheet 4 while keeping the thickness of the EDLC 2 thin. These solutions can be effectively prevented from leaking outside the exterior sheet 4.

Second Embodiment As shown in FIGS. 1B and 2B, the EDLC 2a according to the present embodiment is formed by bending the first lead terminals 18 and 19 and the second lead terminals 28 and 29 drawn from the first seal portion 40. It further has a support sheet 4f for preventing the above. Others are the same as in the first embodiment, and in the following description, the description of the common parts will be partially omitted, and the different parts will be described in detail.

  In the first embodiment described above, as shown in FIG. 2A, the position in the X-axis direction is the same on the front surface 4 a and the back surface 4 b of the exterior sheet 4 in the peripheral edge portion 4 d on the first seal portion side of the exterior sheet 4. . On the other hand, in the present embodiment, the support sheet 4f is formed by extending one of the peripheral edge parts 4d on the first seal part side of the exterior sheet 4 located in the first seal part 40 to the outside.

  With this configuration, the support sheet 4f can be easily formed. The protruding length L4 of the support sheet 4f is longer than the protruding length L1 of the first lead terminal 18 and the second lead terminal 29. L4-L1 is preferably 0.5 to 2 mm.

  By configuring in this way, bending of the first lead terminals 18 and 19 and the second lead terminals 28 and 29 drawn out from the first seal portion 40 can be effectively prevented. Further, by satisfying L4> L1, there is no possibility that the lead terminal 18 comes into contact with the exposed end of the metal sheet (metal sheet 2A in FIG. 2A) in the peripheral edge portion 4d on the first seal portion side of the exterior sheet 4. Short circuit prevention can be achieved.

  In the present embodiment, the terminal strength can be increased by fixing the first lead terminals 18 and 19 and the second lead terminals 28 and 29 to the support sheet 4f with, for example, a heat seal layer. By fixing to the exterior sheet 4f, terminal misalignment hardly occurs and various terminal connections such as ACF connection are facilitated.

Third Embodiment As shown in FIG. 14, in the EDLC 2b of the present embodiment, either one of the lead terminals 19 and 28 is formed longer than the other, and the longer lead terminal 28 is placed on the way. The bent portion is connected to the other lead terminal 19 as a connecting piece 50a. Others are the same as those of the first embodiment, and have the same effects. In the present embodiment, the connection piece 50a is formed by extending any one of the lead terminals 28, and only one place is to be connected, and the connection between the lead terminals 19 and 28 is facilitated. In addition, connection reliability is improved.

Fourth Embodiment As shown in FIG. 15, in the EDLC 2c of the present embodiment, the connection piece 50 is bonded in advance to the surface of the insulating support sheet 4f1, and the support sheet 4f1 is connected to the back surface 4b of the exterior sheet 4. At the same time, the connecting piece 50 connects the lead terminals 19 and 28. Others are the same as those of the first embodiment, and have the same effects. In the present embodiment, the connection piece 50 and the lead terminals 19 and 28 can be easily connected.

Other Embodiments The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

  For example, the laminate type electrochemical device to which the present invention is applied is not limited to EDLC, and can be applied to lithium batteries, lithium battery capacitors, and the like. In the embodiment described above, the two elements 10 and 20 are accommodated in the exterior sheet 4. However, in the present invention, three or more elements may be stacked via the partition sheet 30. However, the total thickness increases according to the number of stacked elements.

Further, in the above-described embodiment, all the lead terminals 18, 19, 28, 29 are taken out of the seal portion with only one side of the rectangular exterior sheet 4, but the present invention is not limited to this. Instead, the lead terminals 18, 19, 28, and 29 may be taken out from the positions of different sides of the rectangular outer sheet 4.
Furthermore, in the above-described embodiment, the structure in the case where one outer sheet 4 is folded back has been described. However, two outer sheets may be prepared and the bonded peripheral edges (four sides) may be heat sealed. . In this case, it is preferable because the thickness can be further reduced.

2, 2a, 2b, 2c ... electric double layer capacitor 4 ... exterior sheet 4a ... front surface 4b ... back surface 4c ... folded peripheral edge 4d ... first seal part side peripheral part 4e ... side peripheral part 4f, 4f1 ... support sheet 10 ... 1st element 11 ... 1st separator layer 12, 14 ... 1st active layer 13, 15 ... 1st collector layer 16, 17 ... 1st internal electrode 18, 19 ... 1st lead terminal 20 ... 2nd element 21 ... Second separator layer 22, 24 ... Second active layer 23, 25 ... Second current collector layer 26, 27 ... Second internal electrode 28, 29 ... Second lead terminal 30 ... Partition sheet 40 ... First seal portion 42 ... 3rd seal part 44 ... 2nd seal part 50 ... Connection piece

Claims (9)

A first element in which a pair of first internal electrodes are stacked so as to sandwich the first separator layer;
A second element in which a pair of second internal electrodes are laminated so as to sandwich the second separator layer;
An exterior sheet covering at least the first element and the second element;
A partition sheet that is laminated between the first element and the second element inside the exterior sheet and separates the first electrolyte solution and the second electrolyte solution,
A first lead terminal connected to at least one first internal electrode of the pair of first internal electrodes;
An electrochemical device having a second lead terminal connected to at least one second internal electrode of the pair of second internal electrodes,
A seal part that is integrated so that a peripheral part of the exterior sheet sandwiches a peripheral part of the partition sheet;
In the seal part, the first lead terminal and the second lead terminal are drawn out of the seal part at different positions along the longitudinal direction of the seal part. A pair of first lead terminals connected to each of the pair of first internal electrodes;
A pair of second lead terminals connected to each of the pair of second internal electrodes,
2. The electrochemical device according to claim 1, wherein the four lead terminals are pulled out to the outside of the seal portion at different positions along the longitudinal direction of the seal portion.   One of the pair of first lead terminals and one of the pair of second lead terminals are adjacent to each other along the longitudinal direction of the seal portion, and are electrically connected to the outside of the seal portion. The electrochemical device according to claim 2, which is connected to the device.   A portion of the seal portion includes a first seal portion, and the first lead terminal and the second lead terminal are located at different positions along the longitudinal direction of the first seal portion. The electrochemical device according to any one of claims 1 to 3, which is drawn out to the outside.   The first seal portion includes a sealing tape that sandwiches the first lead terminal and the second lead terminal, together with a peripheral portion on the first seal portion side of the partition sheet, on the first seal portion side of the exterior sheet. The electrochemical device according to claim 4, wherein the electrochemical device is formed by being sandwiched between the peripheral portions of the substrate and heat-sealed. At both ends in the longitudinal direction of the first seal portion, one end of the third seal portion is continuously formed so as to be connected, and the second end is connected so as to connect the other end of these third seal portions. The seal part is formed continuously,
The third seal part is formed by sandwiching and heat-sealing the side edge of the partition sheet between the side edges of the exterior sheet,
6. The electrochemical device according to claim 4, wherein the second seal portion is formed by heat-sealing a peripheral edge of the bottom of the partition sheet between the folded peripheral edges of the exterior sheet.   The electrochemical device according to any one of claims 4 to 6, further comprising a support sheet for preventing the first lead terminal and the second lead terminal drawn out from the first seal portion from bending.   The electrochemical device according to claim 7, wherein the support sheet is formed by extending one of peripheral edges on the first seal portion side of the exterior sheet positioned in the first seal portion to the outside.   The electrochemical device according to claim 7 or 8, wherein a protruding length of the support sheet is longer than a protruding length of the first lead terminal and the second lead terminal.

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