JP4391861B2 - Electric double layer capacitor and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality and low cost electric double-layer capacitor and a reasonable manufacturing method thereof with which excellent energy-volume efficiency can be ensured and connection with external wires can also be realized easily. <P>SOLUTION: The electric double-layer capacitor comprises a laminate 30 which is constituted by the predetermined number of positive and negative electrodes 20 and separators 25 which are provided among these electrodes; a conductive portion 22 which is exposed like a belt from a polarizing electrode 27 as a part of a collecting electrode 23 of each electrode 20; and a sealing portion 40 for sealing, together with internal and external boundaries of a vessel 10, a conductive portion 22 which is led to the external side from the internal and external boundaries of the vessel 10 for accommodating the laminate 30 together with the electrolyte. The manufacturing method thereof comprises the step of manufacturing a sheet 15A, as a material to form the positive and negative electrodes 20, which is provided with a non-laminated layer region 15b for exposing a raw material layer of the collecting electrode 23, and a hot melt resin 26a of the predetermined width which is bonded to the constant location of the non-laminated layer region 15b from the laminated layer region 15a of the raw material layer of the collecting electrode 23 and the raw material layer of the polarizing electrode 27 and the raw material layer of the polarizing electrode 27. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an electric double layer capacitor and a method for manufacturing the same.

  2. Description of the Related Art In recent years, as various types of power storage devices, attention has been focused on application technologies of electric double layer capacitors that can be rapidly charged and have a long charge / discharge cycle life.

The electric double layer capacitor is composed of a winding type in which a strip-shaped positive electrode body and a negative electrode body are rolled into a roll with a separator interposed therebetween, and a flat plate positive electrode body and a negative electrode body interposed between them. However, it is broadly classified into a laminated type in which the layers are alternately stacked. The following Patent Literature 1 to Patent Literature 6 introduce a part of the investigation results of the prior art.
JP-A-7-94374 JP-A-9-186055 JP-A-11-87195 Japanese Patent Laid-Open No. 11-211985 JP 2000-200740 JP 2001-155713 A

In FIG. 6, an example of a laminated type will be described. Reference numeral 10 denotes a container for sealing the laminated body (capacitor main body) together with the electrolytic solution, and 11 denotes a pair of terminal plates (external electrodes) that are partially drawn out of the container 10. In addition, each terminal board 11 is formed in a short shape from aluminum which is lightweight and has a small electric resistance.
The capacitor body is composed into a predetermined laminate by alternately stacking a positive electrode body (positive electrode body) and a negative electrode body (negative electrode body) with a separator interposed therebetween.
A positive electrode body and a negative electrode body are comprised in flat form from the collector electrode and the polarizable electrode (activated carbon electrode) formed in the both surfaces. These collector electrodes are made of a rectangular metal foil (aluminum foil), and a strip-like conductive portion (lead) is integrally formed on one side of a rectangular plane.
The conductive parts have the same polarity, and a converging part having a corresponding polarity is joined to a pair of terminal plates.

  The container 10 is composed of two container members (a bottom side member and a lid side member) formed by cold pressing from a flexible laminated film (for example, aluminum laminate) including a metal intermediate layer in a plurality of resin layers. When these are combined, the accommodating part of a laminated body is formed between the bottom side member and the lid side member by the concave portions facing each other.

  The capacitor body is housed inside the bottom side member, and the lid side member is placed thereon. At the peripheral edge of the container 10, three sides excluding one side from which the pair of terminal plates 11 (part thereof) are drawn are heat welded (heat sealed). The container 10 can be opened at one side from which the pair of terminal plates 11 protrudes. After the electrolytic solution is injected from the opening and the impregnation treatment of the electrolytic solution is finished, the vacuum pump removes air and moisture. The remaining one side is heat welded (heat sealed).

  7 to 9 illustrate a part of the manufacturing process related to the multilayer type electric double layer capacitor. Reference numeral 15 denotes a sheet for forming a positive electrode body and a negative electrode body, and an overlaid region 15a and a separation layer of a collector electrode material layer (aluminum foil) and a polarizable electrode material layer (activated carbon layer) on both sides thereof. A non-multilayer region 15b in which the material layer of the collector electrode is exposed from the material layer of the polar electrode is formed. The sheet 15 is formed into a belt having a predetermined width, and is rolled into a roll shape for convenience of storage and conveyance. By performing die cutting while unfolding the sheet 15, the flat electrode body 20 including the multilayer portion 21 of the collecting electrode and the polarizable electrode and the strip-shaped conductive portion 22 exposed from the polarizable electrode is formed. Yes (see FIG. 7).

  In the composition process of the laminated body, the required number of positive electrode bodies 20a and negative electrode bodies 20b are alternately laminated with a separator 25 interposed therebetween to form a predetermined laminated body 30. At this time, since the conductive portions 22a and 22b are moved toward one side of the collector electrodes 23a and 23b, the positive electrode body 20a and the negative electrode body 20b are laminated with the front and back being alternately reversed (see FIG. 8). 27 (27a) and 27 (27b) are polarizable electrodes.

  The conductive portions 22 of each electrode body 20 are focused on the same polarity, and the focusing portions 25 are overlapped and joined to a pair of terminal plates 24a and 24b. This joining is processed by spot welding or ultrasonic welding or rivet joining or laser welding. When a heat-meltable resin 26 having a predetermined width is bonded in advance to a fixed position of each terminal plate 24 and one side of the container 10 (an opening from which the terminal plate 24 protrudes to the outside) is heat-sealed, heat constituting the inner surface of the container 10 is obtained. A seal portion 28 that seals the terminal plate 24 together with the opening of the container 10 is formed by thermal welding of the meltable resin and the hot-melt resin 26 of the terminal plate 24 (see FIG. 9). Although not shown, seal portions based on the thermal welding of the hot-melt resins constituting the inner surface of the container 10 are also formed on the other three sides by the heat sealing process. Reference numeral 29 denotes a joint portion between the converging portion of the conductive portion 22 and the terminal plate 24.

  In such an electric double layer capacitor, a high-performance bonding means that has a low resistance and can secure a high-quality bonding portion is required for connection between the terminal plate 24 and the conductive portion 22, which causes a cost increase. In addition, a space for accommodating the joint portion 29 is required inside the container 10, and the multilayer body 30 (capacitor main body) is reduced by that amount, thereby reducing the energy volume efficiency of the electric double layer capacitor (product). is there. In addition, since the terminal plate 24 is a single aluminum plate and has a thickness, it is difficult to bend when connecting to an external wiring (for example, a bus bar). Connection is not easy.

  An object of the present invention is to provide an effective technique for solving such a problem.

In the first invention, as a material for forming a positive electrode and a negative electrode body, an overlapping layer region of a material layer of a collector electrode and a material layer of a polarizable electrode, a material layer of a collector electrode from a material layer of a polarizable electrode A step of creating a sheet comprising a non-multilayer region to be exposed, a heat-meltable resin having a predetermined width bonded to a fixed position of the non-multilayer region, a multilayer portion of a collecting electrode and a polarizable electrode, a rectangular plane A step of forming an electrode body including a conductive portion to which a heat-meltable resin having a predetermined width adheres at a fixed position of a non-multilayer region exposed from one side to one side of a polarizable electrode, and a plurality of positive and negative electrodes A process of composing a laminate by alternately inverting the front and back while interposing a separator between them, and an inside of the container in which the inner surface is formed with a heat-meltable resin The laminated body is accommodated together with an electrolytic solution. And a heat-meltable resin that forms the inner surface together with the opening of the container between the conductive parts of the same-polarity bundle of the conductive parts drawn out from the opening of the container and the conductive part. And a step of sealing by heat welding via a functional resin .

According to the first invention, it is possible to efficiently manufacture a high-quality and inexpensive product (electric double layer capacitor) that has good energy volume efficiency and can be easily and properly connected to external wiring. In the process of creating a sheet, a heat-meltable resin having a predetermined width is also attached to a fixed position of the non-multilayer region. Therefore, in the process of forming an electrode body from the sheet, an electrode body having a heat-meltable resin in the conductive portion is rational. Can be obtained .

As for the electric double layer capacitor, the conductive part exposed in a strip shape from the polarizable electrode as a part of the collecting electrode of each electrode body is drawn out from the opening of the container to the outside, and each conductive material in the bundle of the same polarity is sealed by the seal part. The part is sealed together with the opening of the container. That is, since the conventional terminal board is omitted, the cost of the product can be greatly reduced and the energy volumetric efficiency can be increased. In addition, since the conductive portion of each electrode body is not a single piece having a thickness like a terminal plate, it can be bent freely even if they are bundled, and the follow-up of deformation corresponding to the space (layout) is good. Connection with wiring can be easily performed .

  In FIG. 1, 10 is a container for sealing a laminate (capacitor main body) together with an electrolyte, and 22 is a conductive portion (lead) exposed from a polarizable electrode as a part of a collecting electrode of each electrode body constituting the laminate. It is drawn out from the inner and outer boundaries of the container 10 that houses the laminate together with the electrolyte, and is sealed together with the inner and outer boundaries of the container 10 (opening of the container 10).

  The capacitor body is composed into a predetermined laminate by alternately stacking a positive electrode body (positive electrode body) and a negative electrode body (negative electrode body) with a separator interposed therebetween. A positive electrode body and a negative electrode body are comprised in flat form from the collector electrode and the polarizable electrode (activated carbon electrode) formed in the both surfaces. These collector electrodes are made of a rectangular metal foil (aluminum foil), and a strip-shaped conductive portion 22 (lead) is integrally formed on one side of the rectangular plane. The conductive parts 22 have the same polarity and are drawn out from the inner and outer boundaries of the container 10.

  The container 10 is composed of two container members (a bottom side member and a lid side member) formed by cold pressing from a flexible laminated film (for example, aluminum laminate) including a metal intermediate layer in a plurality of resin layers. When these are combined, the accommodating part of a laminated body is formed between the bottom side member and the lid side member by the concave portions facing each other.

  The capacitor body is housed inside the bottom side member, and the lid side member is placed thereon. At the periphery of the container 10, three sides excluding one side from which the convergence of the conductive portion 22 is drawn are heat-welded (heat sealed). The container 10 can be opened at one side where the converging of the conductive portion 22 protrudes, and after the electrolytic solution is injected from the opening and the electrolytic solution is impregnated, the vacuum pump removes air and moisture. The remaining one side is heat welded (heat sealed).

  The heat-meltable resin is bonded to both surfaces of the region of the conductive portion 22 that is connected to the inner and outer boundaries of the container 10, and the conductive portion together with the heat-meltable resin that forms an inner and outer boundary surface (inner surface of the container) by heat sealing. The sealing part 40 which seals the convergence of 22 is formed.

  With such a configuration, the conductive part 22 exposed in a strip shape from the polarizable electrode as a part of the collecting electrode of each electrode body is drawn out from the inner and outer boundaries of the container 10 and connected to an external wiring or the like (external terminal). ). The converging of the conductive portion 22 is sealed without gaps together with the inner and outer boundaries of the container 10 by the seal portion 40. In other words, the conventional terminal plate 24 (see FIGS. 6 and 9) is omitted, and a high-performance bonding means that can secure a high-quality bonding portion 29 with low resistance for connection between the terminal plate 24 and the conductive portion 22 is provided. No longer needed. Further, a space for accommodating the joint portion 29 between the terminal plate 24 and the conductive portion 22 inside the container 10 is not required.

  For this reason, a significant cost reduction and an increase in energy volume efficiency of the electric double layer capacitor (product) can be obtained. In addition, since the conductive portion 22 of each electrode body is not a single piece having a thickness like the terminal plate 24, it can be bent freely even if they are converged, and the followability of deformation corresponding to the space (layout) is good. Also, it can be easily connected to external wiring.

  2 to 4 illustrate a part of the manufacturing process related to the multilayer type electric double layer capacitor. 15A is a sheet for forming the positive electrode body 20a and the negative electrode body 20b, and includes a material layer (aluminum foil) for collecting electrodes and a material layer (activated carbon layer) for polarizable electrodes formed on both sides thereof. The multi-layer region 15a, the non-multi-layer region 15b where the material layer of the collecting electrode is exposed from the material layer of the polarizable electrode, and the heat-meltable resin 26a having a predetermined width bonded to a fixed position of the non-multi-layer region 15b.

  The sheet 15A is formed in a belt shape having a predetermined width, and is rolled into a roll shape for convenience of storage and transportation. The plate-like electrode body 20 is formed by performing die cutting while developing the sheet 15A. The electrode body 20 includes an overlapping layer portion 21 of a collecting electrode and a polarizable electrode and a strip-shaped conductive portion 22 exposed from the polarizable electrode, and a heat-meltable resin 26 having a predetermined width is provided at a fixed position of the conductive portion 22. (See FIG. 2).

  In the composition process of the laminated body, the required number of positive electrode bodies 20a and negative electrode bodies 20b are alternately laminated with a separator 25 interposed therebetween to form a predetermined laminated body 30. At that time, since the conductive portion 22 approaches one side of the collector electrodes 23a and 23b, the positive electrode body 20a and the negative electrode body 20b are stacked while the surfaces are alternately reversed (see FIG. 3). 27 (27a) and 27 (27b) are polarizable electrodes.

  The conductive portions 22 of the electrode bodies 20 are focused on the same polarity and drawn out from the inner and outer boundaries of the container 10 to the outside. After the electrolytic solution impregnation treatment and the like, when one side of the container 10 (opening in which the converging of the conductive portion 22 protrudes from the inner and outer boundaries of the container 10) is heat-sealed, the heat-meltable resin constituting the inner surface of the container 10 And the heat-meltable resin 26 of the conductive portion 22 form a seal portion 40 that seals the converging of the conductive portion 22 together with the opening of the container 10 (see FIG. 4). Although not shown in the figure, also on the other three sides of the container 10, a seal portion based on heat welding of the hot-melt resins constituting the inner surface of the container 10 is formed by the heat sealing process before injection of the electrolytic solution.

  By setting the process as described above, it is possible to efficiently manufacture a high-quality and inexpensive product (electric double layer capacitor) that has good energy volume efficiency and can be easily and properly connected to external wiring as described above. In the step of forming the sheet 15A, the heat-meltable resin 26a having a predetermined width is also attached to the fixed position of the non-multilayer region 15b. Therefore, in the step of forming the electrode body 20 from the sheet 15A, the heat-meltable resin is applied to the conductive portion 22. The electrode body 20 having 26 is reasonably obtained.

  FIG. 5 is an explanatory diagram of a process for heat-sealing one side of the container 10. The conductive portions 22 of the electrode bodies 20 are converged with the same polarity aligned with the position of the hot-melt resin 26 (overlapping and bundling). The sealing part 40a is formed by heat welding of the hot-melt resin 35 of the container 10 and the hot-melt resin 26 of the conductive part 22 based on the heat sealing process, and the converging of the conductive part 22 is also sealed together with the opening of the container 10. The In this example, the hot-melt resin 26 is bonded to one side instead of both sides of the conductive portion 22. That is, the sheet 15A is bonded to the hot-melt resin 26a only on one surface of the non-multilayer region 15b, and in the process of forming the electrode body 20 from the sheet 15A, the sheet 15A is die-cut from the front side where the heat-melt resin 26a is present. Two types of electrode body 20a (positive electrode body) and an electrode body 20b (negative electrode body) that is die-cut from the back side without the heat-meltable resin 26a are created.

  It is conceivable that the heat-meltable resin 26 of the conductive portion 22 is not bonded to the non-multilayer region 15b in advance in the step of forming the sheet 15A but is bonded after the electrode body 20 is molded. Thereby, creation of the molding material (sheet) of the electrode body 20 is simplified, and the hot-melt resin 26 is bonded to a fixed position according to the stacking order of the electrode bodies 20a and 20b constituting the stacked body 30. In addition, the heat-bonding resin 26 of each conductive portion 22 is easily bundled so as to be aligned at the shortest distance from the laminate 30. For this reason, in the inside of the container 10, there is no need to give slack to some of the conductive portions 22 for the alignment of the hot-melt resin 26, and the improvement of product performance can be promoted.

1 is an external view of an electric double layer capacitor according to an embodiment of the present invention. It is explanatory drawing of a manufacturing process similarly. It is explanatory drawing of a manufacturing process similarly. It is explanatory drawing of a manufacturing process similarly. It is explanatory drawing of a manufacturing process similarly. It is an external view of the conventional electric double layer capacitor. It is explanatory drawing which similarly concerns on a structure. It is explanatory drawing of a manufacturing process similarly. It is explanatory drawing of a manufacturing process similarly.

Explanation of symbols

10 container 15A sheet 15a multi-layer region 15b non-multi-layer region 20 electrode body 20a positive electrode body (positive electrode body)
20b Negative electrode body (negative electrode body)
22 Conductive part 23 (23a, 23b) Collector electrode 25 Separator 26, 26a Heat-meltable resin 27 (27a, 27b) Polarized electrode 30 Laminate (capacitor body)
40, 40a Seal part

Claims (1)

As a material for forming the positive and negative electrode bodies, a multilayer region of the collector electrode material layer and a polarizable electrode material layer, a non-multilayer region that exposes the collector electrode material layer from the polarizable electrode material layer, Creating a sheet comprising a heat-meltable resin having a predetermined width adhered to a fixed position of the non-multilayer region;
Conductive part where a heat-meltable resin with a predetermined width adheres to a fixed position in a non-multilayer region exposed from a sheet to a multilayered part of a collecting electrode and a polarizable electrode, and from one side of a rectangular flat polarizable electrode to one side Forming an electrode body comprising:
A step of composing a laminate by laminating a plurality of positive and negative electrode bodies while alternately inverting the front and back with a separator interposed therebetween,
The step of accommodating the laminate together with the electrolytic solution from the opening of the container whose inner surface is formed with a heat-meltable resin,
A heat-melting resin that forms the inner surface of the bundle of conductive parts with the same polarity of the conductive parts drawn out from the opening of the container together with the opening of the container together with the heat-melting resin of the conductive part. Sealing by heat welding through,
The manufacturing method of the electrical double layer capacitor characterized by including this .

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