JP2009123752A - Electric power storage device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power storage device that prevents a positive electrode layer formed on a positive electrode current terminal portion from corroding and has high weight energy density and volume energy density. <P>SOLUTION: The electric power storage device has a positive electrode 2 and a negative electrode 3 disposed opposite each other with a separator 4 interposed and the positive current terminal portion 5 and a negative current terminal portion 6 are disposed without two-dimensionally overlapping with each other, where the positive electrode 2 includes a positive current collecting foil 12, the positive current terminal portion 5, the positive electrode layer 13, and a positive electrode layer projection portion 21 formed on the positive current terminal portion 5, and the negative electrode 3 includes a negative current collecting foil 14, the negative current terminal portion 6, a negative electrode layer 15, a negative current collecting foil overhang portion 23 formed opposite the positive current terminal portion 5, and a negative electrode layer extension portion 24 formed on the negative current collecting foil overhand portion 23. The positive electrode layer 13 and the negative electrode layer 15 has the same shape and the same area with each other, and the negative electrode extension portion 24 is formed covering the entire surface of the positive electrode projection portion 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric power storage device for storing electric power and a manufacturing method thereof.

Examples of the power storage device include a capacitor and a secondary battery.
A multilayer electric double layer capacitor known as one of capacitors includes, for example, a plurality of cells stored in a storage container. The plurality of cells are stacked in parallel with each other. Each cell has a positive electrode having a positive current terminal part, a negative electrode having a negative current terminal part, and a porous separator impregnated with an electrolytic solution.
The positive electrode side electrode and the negative electrode side electrode are arranged to face each other via a separator, and the positive electrode current terminal part and the negative electrode current terminal part are arranged so as not to overlap in a plane. The electric double layer capacitor accumulates electric charges in an electric double layer formed at the interface between the positive electrode or the negative electrode and the electrolyte.

  The positive electrode side electrode and the negative electrode side electrode are made of a positive electrode current collector foil and a negative electrode current collector foil made of a conductor such as aluminum and having a current terminal portion formed at an end thereof, and formed on a current collector foil made of a carbon material such as activated carbon. Each of the positive electrode layer and the negative electrode layer is formed into a sheet shape. Moreover, the positive electrode side electrode and the negative electrode side electrode each have polarizability. The separator is made of an insulating material. The positive electrode layer and the negative electrode layer have the same shape and area as each other, and are orthogonal to the cell stacking direction.

The electric double layer capacitor has a very large capacitance as compared with a general aluminum electrolytic capacitor. In addition, the electric double layer capacitor does not involve a chemical reaction during charge / discharge, and charges are directly accumulated in the positive electrode and the negative electrode, so that a large current can be charged / discharged instantaneously and high charge / discharge efficiency is obtained. be able to. Furthermore, the electric double layer capacitor can realize a charge / discharge count of about 100,000 times or more and a life of about 10 years or more in a normal environment, and has high reliability.
Therefore, the electric double layer capacitor has been attracting attention as a key device for realizing energy saving and reduction of carbon dioxide emission, such as a power source for home appliances and hybrid vehicles.

As a method for producing the positive electrode and the negative electrode of the electric double layer capacitor, after applying and drying the paste of the electrode layer material on a predetermined position of the fed roll-shaped current collector foil, by punching, There is a method of punching the current collector foil on which the electrode layer is formed together with the current terminal portion (for example, see Patent Document 1).
However, in consideration of the occurrence of displacement in the width direction of the current collector foil or dripping of the paste after application, the position of the paste applied to the roll-shaped current collector foil is precisely controlled to the predetermined position. It is very difficult. If the current collector foil is displaced or the paste is dripped, the electrode layer may protrude from the current terminal portion.

  At this time, in the positive electrode and the negative electrode facing each other with the separator interposed therebetween, the positive current terminal portion and the negative current terminal portion are arranged so as not to overlap in a plane, so that they protrude beyond the positive current terminal portion. In the positive electrode layer formed in this manner, there is no opposing negative electrode layer. That is, the positive electrode layer formed on the positive electrode current terminal portion is not covered with the negative electrode layer.

If there is a positive electrode layer that is not covered by the negative electrode layer and a voltage is applied between the positive electrode and the negative electrode, the voltage is applied at the portion of the positive electrode layer that is not covered by the negative electrode layer. Is abnormally high and this part is known to corrode locally.
It is also known that the charge / discharge characteristics of an electric double layer capacitor deteriorate when gas bubbles generated due to corrosion adhere to the positive electrode layer.
Therefore, the positive electrode on which the positive electrode layer is formed so as to protrude from the positive current terminal portion cannot be used, resulting in a problem that the yield is deteriorated and the cost is increased.

  Therefore, in order to solve the above-described problems, the conventional electric double layer capacitor has a positive electrode side electrode and a negative electrode side electrode facing each other by making the area of the negative electrode layer larger than the area of the positive electrode layer, The entire surface of the positive electrode layer is covered with the negative electrode layer (see, for example, Patent Document 2).

In the conventional electric double layer capacitor, the area of the negative electrode layer is made larger than the area of the positive electrode layer, so that the positive electrode layer formed on the positive current terminal portion is not covered with the negative electrode layer. The positive electrode layer is not present.
At this time, the negative electrode layer that does not face the positive electrode layer, that is, the negative electrode layer corresponding to the outer peripheral portion of the positive electrode layer, cannot store charges and does not function as an electric double layer capacitor.
Therefore, the weight of the electric double layer capacitor increases and the size increases by the amount of the negative electrode layer that does not function as an electric double layer capacitor and the negative electrode current collector foil on which this portion of the negative electrode layer is formed.

JP 2006-324284 A Japanese Patent Laid-Open No. 2002-75802

However, high weight energy density and volume energy density are required for electric double layer capacitors.
The electric double layer capacitor described in Patent Document 2 has a problem in that the weight energy density and the volume energy density are reduced because the extra negative electrode current collector foil and the negative electrode layer increase the weight and increase the size. there were.
Such a problem is not limited to the electric double layer capacitor, and the positive electrode side electrode and the negative electrode side electrode on which the electrode layer is applied and formed are opposed to each other, and the positive electrode current terminal portion and the negative electrode current terminal portion are planar. This is a problem common to power storage devices having a structure arranged so as not to overlap.

  The present invention has been made to solve the above-described problems, and its purpose is to prevent corrosion of the positive electrode layer formed on the positive electrode current terminal portion, and to achieve high weight energy density and volume. An object of the present invention is to provide a power storage device capable of realizing energy density.

  In the power storage device according to the present invention, a positive electrode having a positive current terminal portion and a negative electrode having a negative current terminal portion are arranged to face each other via a separator, and the positive current terminal portion and the negative current terminal portion are planar. The positive electrode is composed of a positive electrode current collector foil formed of a conductor, a positive electrode current terminal portion formed extending from the positive electrode current collector foil, and a positive electrode current collector. A negative electrode current collector foil including a positive electrode layer formed on a conductive foil, and a positive electrode layer protruding from a positive electrode terminal extending from the positive electrode layer, wherein the negative electrode is formed of a conductor. And a negative electrode current terminal part formed extending from the negative electrode current collector foil, a negative electrode layer formed on the negative electrode current collector foil, and a negative electrode current collector part formed so as to face the positive electrode current terminal part The negative electrode current collector foil overhang and the negative electrode layer A negative electrode layer extension formed on the negative electrode current collector foil overhanging portion, the positive electrode layer and the negative electrode layer have the same shape and area, and the negative electrode layer extension is the positive electrode layer It is formed so as to cover the entire surface of the protruding portion.

According to the power storage device of the present invention, the positive electrode layer and the negative electrode layer have the same shape and area. Moreover, the negative electrode side electrode was formed so as to cover the entire surface of the positive electrode electrode layer protruding portion on the negative electrode current collector foil projecting portion formed so as to face the positive electrode current terminal portion and on the negative electrode current collector foil projecting portion A negative electrode layer extension.
Therefore, corrosion of the positive electrode layer (positive electrode layer protrusion) formed on the positive current terminal portion can be prevented, and high weight energy density and volume energy density can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.
In the following embodiments, an electric double layer capacitor will be described as an example of the power storage device.

Embodiment 1 FIG.
FIG. 1 is a perspective view schematically showing a multilayer body 1 of an electric double layer capacitor according to Embodiment 1 of the present invention.
In FIG. 1, the electric double layer capacitor has a multilayer body 1 in which a plurality of cells are stacked in parallel with each other. Each cell of the laminate 1 includes a positive polarizable electrode 2 (hereinafter referred to as “positive electrode 2”) and a negative polarizable electrode 3 (hereinafter referred to as “negative electrode 3”). The configuration is such that the separator 4 is disposed to face the separator 4.

  The positive electrode 2 and the negative electrode 3 each have a positive current terminal 5 and a negative current terminal 6. The positive electrode current terminal portions 5 and the negative electrode current terminal portions 6 of each cell overlap each other in the cell stacking direction. Moreover, the positive electrode current terminal part 5 and the negative electrode current terminal part 6 are arrange | positioned so that it may not overlap planarly.

FIG. 2 is a cross-sectional view schematically showing the electric double layer capacitor according to Embodiment 1 of the present invention. FIG. 3 is a front view showing the electric double layer capacitor according to Embodiment 1 of the present invention.
2 and 3, the laminate 1 is stored in a storage container 11.
The positive electrode 2 includes a positive current collector foil 12 having a positive current terminal portion 5 formed at an end thereof, and a positive electrode layer 13 applied and formed on both surfaces of the positive current collector foil 12. The negative electrode 3 includes a negative electrode current collector foil 14 having a negative electrode current terminal portion 6 formed at an end thereof, and a negative electrode layer 15 applied and formed on one or both surfaces of the negative electrode current collector foil 14. .

A positive electrode current terminal 16 and a negative electrode current terminal 17 for making electrical connection with the outside of the storage container 11 are fixed to the storage container 11 so as to penetrate therethrough.
The positive electrode current terminal portion 5 of each cell is bent toward the positive electrode current terminal 16 side and connected to the positive electrode current terminal 16 by spot welding. Further, the negative electrode current terminal portion 6 of each cell is bent to the negative electrode current terminal 17 side and connected to the negative electrode current terminal 17 by spot welding.

The separator 4 is formed of a porous film impregnated with an electrolytic solution, and has a shape in which a rectangular sheet is folded in half at an intermediate portion in the longitudinal direction. The separator 4 is disposed so as to wrap the positive electrode 2 from the side opposite to the positive electrode current terminal portion 5 of the positive electrode 2 and so that the thickness direction of the separator 4 coincides with the thickness direction of the positive electrode 2. Has been.
Moreover, the separator 4 has a size that covers the entire surface of the positive electrode layer 13 and a positive electrode layer protruding portion described later in order to prevent a short circuit. That is, the two opposite surfaces of the separator 4 are disposed so as to include the positive electrode layer 13 and the positive electrode layer protruding portion.

Next, detailed structures of the positive electrode 2 and the negative electrode 3 of the electric double layer capacitor will be described with reference to FIGS. 4 and 5.
4 is a front view showing positive electrode 2 of the electric double layer capacitor according to Embodiment 1 of the present invention.
In FIG. 4, the positive electrode 2 includes a positive current collector foil 12, a positive current terminal portion 5, a positive electrode layer 13, and a positive electrode layer protruding portion 21.

The positive electrode current collector foil 12 is made of, for example, aluminum. The positive electrode current terminal portion 5 is formed extending from the positive electrode current collector foil 12.
The positive electrode layer 13 is formed by applying a paste of an electrode layer material to be described later (hereinafter abbreviated as “electrode layer paste”) to one or both surfaces of the positive electrode current collector foil 12. The positive electrode layer protruding portion 21 is formed together with the positive electrode layer 13 on the positive electrode current terminal portion 5 when an electrode layer paste is applied to the positive electrode current collector foil 12.

FIG. 5 is a front view showing negative electrode 3 of electric double layer capacitor according to Embodiment 1 of the present invention.
In FIG. 5, the negative electrode side electrode 3 includes a negative electrode current collector foil 14, a negative electrode current terminal portion 6, a negative electrode layer 15, a negative electrode layer protruding portion 22, a negative electrode current collector foil projecting portion 23, and a negative electrode layer. An extension 24.

The negative electrode current collector foil 14 is made of, for example, aluminum. The negative electrode current terminal portion 6 is formed extending from the negative electrode current collector foil 14.
The negative electrode layer 15 is formed by applying an electrode layer paste to one side or both sides of the negative electrode current collector foil 14. The negative electrode layer protruding portion 22 is formed together with the negative electrode layer 15 on the negative electrode current terminal portion 6 when an electrode layer paste is applied to the negative electrode current collector foil 14.

The negative electrode current collector foil projecting portion 23 is formed to extend from the negative electrode current collector foil 14 so as to face the positive electrode current terminal portion 5 with the separator 4 interposed therebetween.
When the electrode layer paste is applied to the negative electrode current collector foil 14, the negative electrode layer extension part 24 is formed on the negative electrode current collector foil projecting part 23 together with the negative electrode layer 15 and the negative electrode layer protrusion 22.

4 and 5, the positive electrode layer 13 and the negative electrode layer 15 have the same shape and area.
Further, the negative electrode layer extension 24 formed on the negative current collector foil projecting portion 23 and the positive electrode layer protrusion 21 formed on the positive current terminal portion 5 face each other with the separator 4 interposed therebetween. The negative electrode layer extension 24 has a larger area than the positive electrode layer protrusion 21 and is formed to cover the entire surface of the positive electrode layer protrusion 21.

Next, a method for manufacturing the electric double layer capacitor will be described. In this embodiment, it is assumed that the positive electrode layer 13 and the negative electrode layer 15 are 100 mm in length and 100 mm in width, respectively.
First, a method for manufacturing the positive electrode 2 and the negative electrode 3 will be described with reference to FIGS.
FIG. 6 is an explanatory diagram showing a method of manufacturing the positive electrode 2 of the electric double layer capacitor according to Embodiment 1 of the present invention. FIG. 7 is an explanatory diagram showing a method for manufacturing the negative electrode 3 of the electric double layer capacitor according to Embodiment 1 of the present invention.

In FIG. 6, the roll feeder 31 is provided with an aluminum foil roll 32 (first current collector foil roll) that becomes the positive electrode current collector foil 12 and the positive electrode current terminal portion 5. An electrode layer is formed on one or both surfaces of the aluminum foil roll 32 by applying an electrode layer paste to be the positive electrode layer 13 and the positive electrode layer protruding portion 21 with a coating device (not shown). The electrode layer paste applied to the aluminum foil roll 32 is applied on the basis of the center in the width direction of the aluminum foil roll 32.
The positive electrode side electrode 2 is formed by pressing a cutting die (not shown) against the fed aluminum foil roll 32 with a press machine (not shown) to obtain the positive current collector foil 12, the positive current terminal portion 5, and the positive electrode The layer 13 and the positive electrode layer protruding portion 21 are manufactured by being integrally punched.

In FIG. 7, the roll feeder 31 is provided with an aluminum foil roll 33 (second current collector foil roll) serving as the negative electrode current collector foil 14, the negative electrode current terminal portion 6, and the negative electrode current collector foil extending portion 23. Yes. On one side or both sides of the aluminum foil roll 33, an electrode layer paste is applied by a coating apparatus to form the negative electrode layer 15, the negative electrode layer protrusion 22, and the negative electrode layer extension 24, thereby forming an electrode layer. The electrode layer paste applied to the aluminum foil roll 33 is applied with the center in the width direction of the aluminum foil roll 33 as a reference.
The negative electrode side electrode 3 is formed by pressing a metal mold against the fed aluminum foil roll 33 with a press machine, so that the negative electrode current collector foil 14, the negative electrode current terminal portion 6, the negative electrode current collector foil projecting portion 23, the negative electrode layer 15, and the negative electrode The layer protrusion 22 and the negative electrode layer extension 24 are integrally punched.

Here, it is assumed that the aluminum foil rolls 32 and 33 have a width of 300 mm, a thickness of 50 μm, and a length of 200 m. The general thickness of the current collector foils such as the positive electrode current collector foil 12 and the negative electrode current collector foil 14 is 20 μm to 50 μm, and these thicknesses correspond to the charge / discharge current when charging / discharging the electric double layer capacitor. Is selected accordingly.
When the charge / discharge current is large, a thick current collector foil is selected in order to reduce the internal resistance. When the charge / discharge current is small, that is, when the charge / discharge time may be long, a thin current collector foil is selected in order to reduce the size of the electric double layer capacitor.
As the material for the current collector foil, other conductive materials such as copper, stainless steel or nickel may be used in addition to aluminum.

  The electrode layer paste applied to the aluminum foil rolls 32 and 33 is composed of, for example, a carbon material such as activated carbon that has been activated into particles having a diameter of about 10 μm, and a binder for binding the particles. . As the carbon material, steam activated activated carbon, alkaline activated carbon, nanogate carbon, or the like is used. As the binder, fluorine resin such as PTFE (polytetrafluoroethylene) or SBR (styrene butadiene rubber) or acrylic synthetic rubber is used.

The electrode layer paste applied to one or both sides of the aluminum foil rolls 32 and 33 is formed by binding a carbon material to the entire surface of the positive electrode current collector foil 12 and the negative electrode current collector foil 14 with a binder, and the positive electrode layer 13 and the negative electrode layer. An electrode layer such as the electrode layer 15 is formed.
That is, the outer shapes of the positive electrode layer 13 and the negative electrode layer 15 are the same as the positive electrode current collector foil 12 and the negative electrode current collector foil 14.

Moreover, the general thickness of electrode layers, such as the positive electrode layer 13 and the negative electrode layer 15, is 50 micrometers-150 micrometers, and each is optimal by the kind of carbon material used with the positive electrode layer 13 and the negative electrode layer 15 respectively. The thickness is different. Here, for example, the positive electrode layer 13 is 100 μm and the negative electrode layer 15 is 150 μm.
In addition, as a formation method of an electrode layer, there exist a rolling method, a molding method, etc. other than the coating method.

By the way, in general, the coating paste dam of the coating apparatus in which the electrode layer paste applied to the aluminum foil roll is stored is positioned according to a preset coating width (width for applying the electrode layer paste). Has been.
However, as described above, the coating width is kept constant over the entire length of the aluminum foil roll in consideration of the shift in the width direction of the aluminum foil roll and the occurrence of dripping of the electrode layer paste after application. It is difficult. In addition, it becomes more difficult to keep the coating width constant due to misalignment of the coating paste dam and oozing of the electrode layer paste from the contact surface between the coating paste dam and the aluminum foil roll. .
Such a tendency becomes more prominent as the coating speed increases for mass production and cost reduction, and the coating width unevenness increases.

That is, when the coating width is set to 200 mm, the electrode layer may be formed to protrude on the positive electrode current terminal portion or the negative electrode current terminal portion, or the area of the positive electrode layer or the negative electrode layer may be insufficient. There is.
When the electrode layer is formed on the positive electrode current terminal portion and when the area of the negative electrode layer is insufficient, there is a positive electrode layer that is not covered by the negative electrode layer. Corrosion of the positive electrode layer occurs at the portion. In addition, when the area of the positive electrode layer is insufficient, the area of the positive electrode layer that functions as an electric double layer capacitor is reduced, so that the performance as an electric double layer capacitor is impaired.

Therefore, in this embodiment, when the electrode layer paste is applied to the aluminum foil roll 32, the coating width on the aluminum foil roll 32 is 210 mm so that the positive electrode layer protruding portion 21 is formed together with the positive electrode layer 13. It is set to (first coating width).
Therefore, even when the aluminum foil roll 32 is displaced in the width direction, the possibility that the area of the positive electrode layer 13 is insufficient is reduced.

In this embodiment, when the electrode layer paste is applied to the aluminum foil roll 33, the coating width on the aluminum foil roll 33 is 220 mm so that the negative electrode layer extension 24 is formed together with the negative electrode layer 15. (Second coating width) is set.
Therefore, even if the aluminum foil roll 33 is displaced in the width direction, the possibility that the area of the negative electrode layer 15 is insufficient is reduced.
The coating width for the aluminum foil roll 33 is set to be 10 mm wider than the coating width for the aluminum foil roll 32.
Therefore, even if the aluminum foil roll 32 is shifted to the left and right by about 5 mm at the maximum in the width direction, the entire surface of the positive electrode layer protruding portion 21 can be covered by the negative electrode layer extension 24, and the negative electrode layer 15 The uncovered positive electrode layer 13 can be eliminated.

Subsequently, the positive electrode 2 manufactured as described above is wrapped with a separator 4 and is opposed to the negative electrode 3 to form a cell.
The separator 4 may be made of a fibrillated film such as polypropylene, polytetrafluoroethylene (PTFE) or silica-mixed polyethylene in addition to cellulose, glass fiber, and nonwoven fabric such as natural pulp, natural cellulose, and solvent-spun cellulose. A porous film is used. Here, for example, a porous film made of polypropylene and having a thickness of 25 μm is used.

The separator 4 is impregnated with an electrolytic solution. The electrolyte impregnated in the separator 4 can be transmitted in the thickness direction of the separator 4 through the holes formed in the thickness direction of the separator 4.
The electrolytic solution is an electrolyte dissolved in a solvent, an ionic liquid (ionic liquid), or the like.

As the electrolyte, for example, a combination of a cation and an anion is used. At this time, as the cation, pyrrolidinium compound, spirobipyrrolidinium, dimethylpyrrolidinium, diethylpyrrolidinium, ethylmethylpyrrolodium, quaternary ammonium, 1,3-dialkylimidazolium, or 1,2,3-tri Alkyl imidazolium or the like is used. In addition, as anions, salts of BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , or CF ₃ SO ₃ ^— , 1-ethyl-3-methylimidazolium (EMI), 1,2-dimethyl-3-propylimidazo AlCl ₄ of helium (DMPI) ^- and BF ₄ ^- salts such as or the like is used.
As the solvent, one kind of solvent selected from propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dimethoxymethane, diethoxyethane, γ-butyllactone, acetonitrile, propionitrile, or two or more kinds of solvents. A mixed solvent or the like is used.

Next, a stacked body 1 is formed by stacking a plurality of cells formed as described above.
Here, when the stacked body 1 is formed, when the plurality of positive electrode side electrodes 2 and the negative electrode side electrodes 3 are stacked so as to be displaced from each other in a plane, the positive electrode layer 13 that is not covered with the negative electrode layer 15. Will exist.
However, since the positive electrode layer 13 and the negative electrode layer 15 have the same shape, the positive electrode side electrode can be obtained by aligning the positive electrode current terminal portion 5 and the negative electrode current terminal portion 6 with each other as a reference. 2 and the negative electrode 3 can be easily aligned. At this time, the positive electrode side electrode 2 and the negative electrode side electrode 3 can be more easily aligned by using the negative electrode current collector foil projecting portion 23 for alignment.

Subsequently, the laminate 1 formed as described above is stored in the storage container 11, and the positive electrode current terminal portion 5 and the negative electrode current terminal portion 6 of each cell are spotted on the positive electrode current terminal 16 and the negative electrode current terminal 17, respectively. It welds and manufactures an electric double layer capacitor.
The storage container 11 is made of an aluminum laminate film, plastic, various metals, or the like.

According to the electric double layer capacitor in accordance with Embodiment 1 of the present invention, positive electrode layer 13 and negative electrode layer 15 have the same shape and area. The negative electrode layer extension 24 has a larger area than the positive electrode layer protrusion 21 and is formed to cover the entire surface of the positive electrode layer protrusion 21.
As a result, the entire surfaces of the positive electrode layer 13 and the positive electrode layer protrusion 21 are covered with the negative electrode layer 15, the negative electrode layer protrusion 22, and the negative electrode layer extension 24.
Therefore, it is possible to prevent an abnormal increase in voltage at the positive electrode layer protruding portion 21 formed on the positive current terminal portion 5 and to prevent corrosion of the positive electrode layer protruding portion 21.

Further, the negative electrode layer extension portion 24 formed on the negative electrode current collector foil projecting portion 23 and the positive electrode layer protruding portion 21 formed on the positive current terminal portion 5 face each other with the separator 4 therebetween.
Thereby, electric charges can be accumulated in the positive electrode layer protruding portion 21, and the positive electrode layer protruding portion 21 can be utilized as an effective area of the electric double layer capacitor.
Therefore, for example, compared with the case where the area of a negative electrode layer is made larger than the area of a positive electrode layer, a high weight energy density and volume energy density are realizable.

The coating width for the aluminum foil roll 33 is set wider than the coating width for the aluminum foil roll 32.
As a result, even if the positive electrode layer protrusion 21 is displaced due to the displacement in the width direction of the aluminum foil roll 32, the entire surface of the positive electrode layer protrusion 21 can be covered by the negative electrode layer extension 24. it can.
Therefore, there is no need to discard the positive electrode 2 formed by shifting the positive electrode layer protruding portion 21, so that the yield can be improved and the cost can be reduced.

Embodiment 2. FIG.
In the first embodiment, the negative electrode layer protruding portion 22 is formed in the negative current terminal portion 6. The negative electrode layer protrusion 22 does not lead to corrosion even if it exists. However, since the negative electrode layer protruding portion 22 cannot store charges, it does not function as an electric double layer capacitor.
Therefore, it is considered that the negative electrode layer protruding portion 22 is used as an effective area of the electric double layer capacitor.

FIG. 8 is a front view showing a positive electrode 2A of an electric double layer capacitor according to Embodiment 2 of the present invention.
In FIG. 8, the positive electrode 2 </ b> A includes a positive current collector foil projecting portion 41 and a positive electrode layer extending portion 42.
The positive electrode current collector foil projecting portion 41 is formed to extend from the positive electrode current collector foil 12 so as to face the negative electrode current terminal portion 6 through the separator 4.
When the electrode layer paste is applied to the positive electrode current collector foil 12, the positive electrode layer extension part 42 is formed on the positive electrode current collector foil projecting part 41 together with the positive electrode layer 13 and the positive electrode layer protrusion 21.

Here, the positive electrode layer extension portion 42 formed on the positive electrode current collector overhang portion 41 and the negative electrode layer protrusion portion 22 formed on the negative current terminal portion 6 face each other with the separator 4 interposed therebetween. . Further, the positive electrode layer extension 42 has a smaller area than the negative electrode layer protrusion 22 and is formed so that the entire surface is covered with the negative electrode layer protrusion 22.
Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

Next, a manufacturing method of the positive electrode 2A will be described with reference to FIG. The description of the manufacturing method similar to that of the first embodiment will be omitted.
FIG. 9 is an explanatory view showing a method of manufacturing the positive electrode 2A of the electric double layer capacitor according to Embodiment 2 of the present invention.

In FIG. 9, the roll feeder 31 is provided with an aluminum foil roll 32 serving as the positive electrode current collector foil 12, the positive electrode current terminal portion 5, and the positive electrode current collector foil projecting portion 41. On one or both sides of the aluminum foil roll 32, an electrode layer is formed by applying an electrode layer paste to be the positive electrode layer 13, the positive electrode layer protruding portion 21, and the positive electrode layer extension portion 42 with a coating apparatus. The electrode layer paste applied to the aluminum foil roll 32 is applied on the basis of the center in the width direction of the aluminum foil roll 32.
The positive electrode side electrode 2A is formed by pressing a die against the fed aluminum foil roll 32 with a press machine, to form a positive current collector foil 12, a positive current terminal portion 5, a positive current collector foil projecting portion 41, a positive electrode layer 13, a positive electrode The layer protrusion 21 and the positive electrode layer extension 42 are integrally punched.

According to the electric double layer capacitor according to the second embodiment of the present invention, the positive electrode layer extension portion 42 formed on the positive electrode current collector foil projecting portion 41 and the negative electrode layer protrusion portion formed on the negative current terminal portion 6 22 are opposed to each other via the separator 4. Further, the positive electrode layer extension 42 has a smaller area than the negative electrode layer protrusion 22 and is formed so that the entire surface is covered with the negative electrode layer protrusion 22.
Accordingly, charges can be accumulated in the negative electrode layer protrusion 22 without the presence of the positive electrode layer 13 not covered with the negative electrode layer 15, and the negative electrode layer protrusion 22 can be used as an effective electric double layer capacitor. It can be used as an area.
Therefore, higher weight energy density and volume energy density can be realized.

Embodiment 3 FIG.
In the said Embodiment 1, 2, the positive electrode current terminal part 5 and the negative electrode current terminal part 6 were formed in the same edge | side about the positive electrode current collector foil 12 and the negative electrode current collector foil 14, respectively. However, the present invention is not limited to this, and the positive current collector foil and the negative current collector foil may be formed with a positive current terminal portion and a negative current terminal portion on opposite sides.
Hereinafter, a case where the positive electrode current terminal portion and the negative electrode current terminal portion are formed on opposite sides of the positive electrode current collector foil and the negative electrode current collector foil will be described.

FIG. 10 is a front view showing a positive electrode 2B of an electric double layer capacitor according to Embodiment 3 of the present invention.
10, the positive electrode 2B includes a positive current terminal portion 5B and a positive electrode layer protruding portion 21B instead of the positive current terminal portion 5 and the positive electrode layer protruding portion 21 shown in FIG.
The positive electrode current terminal portion 5 </ b> B extends from the positive electrode current collector foil 12. The positive electrode layer protruding portion 21 </ b> B is formed together with the positive electrode layer 13 on the positive current terminal portion 5 </ b> B when the electrode layer paste is applied to the positive electrode current collector foil 12.

FIG. 11 is a front view showing a negative electrode 3B of an electric double layer capacitor according to Embodiment 3 of the present invention.
In FIG. 11, the negative electrode 3 </ b> B is replaced with a negative current terminal 6, a negative electrode layer protrusion 22, a negative current collector foil extension 23, and a negative electrode layer extension 24 shown in FIG. 5. Part 6B, negative electrode layer protrusion 22B, negative electrode current collector foil extending part 23B, and negative electrode layer extension part 24B.

The negative electrode current terminal portion 6B is formed extending from the side of the negative electrode current collector foil 14 facing the positive electrode current terminal portion 5B. The negative electrode layer protruding portion 22B is formed together with the negative electrode layer 15 on the negative current terminal portion 6B when the electrode layer paste is applied to the negative electrode current collector foil 14.
The negative electrode current collector foil projecting portion 23B extends from the negative electrode current collector foil 14 so as to face the positive electrode current terminal portion 5B with the separator 4 interposed therebetween.
When the electrode layer paste is applied to the negative electrode current collector foil 14, the negative electrode layer extension part 24B is formed on the negative electrode current collector foil projecting part 23B together with the negative electrode layer 15 and the negative electrode layer protrusion 22B.
Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

Next, a manufacturing method of the negative electrode 3B will be described with reference to FIG. The description of the manufacturing method similar to that of the first embodiment will be omitted.
FIG. 12 is an explanatory view showing a method of manufacturing the negative electrode 3B of the electric double layer capacitor according to Embodiment 3 of the present invention.

  In FIG. 12, the roll feeder 31 is provided with an aluminum foil roll 33 serving as the negative electrode current collector foil 14, the negative electrode current terminal part 6B, and the negative electrode current collector foil projecting part 23B. An electrode layer is formed on one or both surfaces of the aluminum foil roll 33 by applying an electrode layer paste to be the positive electrode layer 13, the negative electrode layer protruding portion 22 </ b> B, and the negative electrode layer extension 24 </ b> B using a coating apparatus. The electrode layer paste applied to the aluminum foil roll 33 is applied with the center in the width direction of the aluminum foil roll 33 as a reference.

The negative electrode side electrode 3B is formed by pressing a die against the fed aluminum foil roll 33 with a press machine, and the negative electrode current collector foil 14, the negative electrode current terminal part 6B, the negative electrode current collector foil projecting part 23B, the positive electrode layer 13, and the negative electrode It is manufactured by integrally punching the layer protrusion 22B and the negative electrode layer extension 24B.
At this time, the negative electrode current collector foil projecting portion 23 </ b> B and the negative electrode layer protruding portion 22 </ b> B are located near the center of the aluminum foil roll 33 in the width direction.

According to the electric double layer capacitor according to the third embodiment of the present invention, when manufacturing the negative electrode 3B, the negative electrode current collector foil projecting portion 23B is located near the center in the width direction of the aluminum foil roll 33. Become.
Therefore, the negative electrode layer protrusion 22B can be easily formed.

In addition to the electrode shown in FIG. 10, the cathode electrode facing the anode 3 </ b> B is a cathode current collector formed so as to face the anode current terminal as in the embodiment 2 described above. It may include a foil overhanging portion and a positive electrode layer extension portion formed on the positive electrode current collector foil overhanging portion.
Also in this case, the same effects as those of the first to third embodiments can be obtained.

In the first to third embodiments, the electric double layer capacitor has been described as an example of the power storage device. However, the present invention is not limited to this.
The present invention can be applied to a stacked power storage device in which current terminal portions are divided on the positive electrode side and the negative electrode side. Examples of the power storage device include a capacitor such as a hybrid capacitor, a lithium ion capacitor, a nano storage capacitor, and a nano gate capacitor, and a secondary battery such as a lithium ion battery.
Even when applied to these power storage devices, the same effects as in the first to third embodiments can be obtained.

1 is a perspective view schematically showing a multilayer body of an electric double layer capacitor according to Embodiment 1 of the present invention. It is sectional drawing which shows typically the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is a front view which shows the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is a front view which shows the positive electrode side electrode of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is a front view which shows the negative electrode side electrode of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the manufacturing method of the positive electrode of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the manufacturing method of the negative electrode side electrode of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is a front view which shows the positive electrode side electrode of the electric double layer capacitor which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the manufacturing method of the positive electrode of the electric double layer capacitor which concerns on Embodiment 2 of this invention. It is a front view which shows the positive electrode side electrode of the electric double layer capacitor which concerns on Embodiment 3 of this invention. It is a front view which shows the negative electrode side electrode of the electric double layer capacitor which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the manufacturing method of the negative electrode side electrode of the electric double layer capacitor which concerns on Embodiment 3 of this invention.

Explanation of symbols

  2, 2A, 2B Positive electrode side, 3, 3B Negative electrode side electrode, 4 Separator, 5, 5B Positive electrode current terminal portion, 6, 6B Negative electrode current terminal portion, 12 Positive electrode current collector foil, 13 Positive electrode layer, 14 Negative electrode current collector Foil, 15 Negative electrode layer, 21, 21B Positive electrode layer protrusion, 22, 22B Negative electrode layer protrusion, 23 Negative current collector foil overhang, 24, 24B Negative electrode layer extension, 32 Aluminum foil roll (first collection) (Electric foil roll), 33 aluminum foil roll (second current collector foil roll), 41 positive electrode current collector foil projecting portion, 42 positive electrode electrode layer extension portion.

Claims (3)

A positive electrode having a positive current terminal portion and a negative electrode having a negative current terminal portion are arranged to face each other via a separator, and the positive current terminal portion and the negative current terminal portion are arranged so as not to overlap in a plane. A power storage device,
The positive electrode is
A positive electrode current collector foil formed of a conductor;
The positive electrode current terminal portion formed extending from the positive electrode current collector foil;
A positive electrode layer formed on the positive current collector foil;
A positive electrode layer protruding portion that extends from the positive electrode layer and is formed on the positive electrode current terminal.
The negative electrode is
A negative electrode current collector foil formed of a conductor;
The negative electrode current terminal portion formed extending from the negative electrode current collector foil;
A negative electrode layer formed on the negative electrode current collector foil;
A negative electrode current collector foil projecting portion formed extending from the negative electrode current collector foil so as to face the positive electrode current terminal portion;
A negative electrode layer extension part extending from the negative electrode layer and formed on the negative electrode current collector foil overhang part,
The positive electrode layer and the negative electrode layer have the same shape and area, and the negative electrode layer extension is formed to cover the entire surface of the protruding portion of the positive electrode layer. Power storage device. The positive electrode is
A positive current collector foil projecting portion formed extending from the positive current collector foil so as to face the negative current terminal portion;
A positive electrode layer extension extending from the positive electrode layer and formed on the positive electrode current collector foil overhang,
The negative electrode includes a negative electrode layer protrusion that extends from the negative electrode layer and is formed on the negative current terminal.
The power storage device according to claim 1, wherein the negative electrode layer protruding portion is formed to cover the entire surface of the positive electrode layer extension. A positive electrode having a positive current terminal portion and a negative electrode having a negative current terminal portion are arranged to face each other via a separator, and the positive current terminal portion and the negative current terminal portion are arranged so as not to overlap in a plane. A method for manufacturing a power storage device, comprising:
Applying the electrode layer material of the positive electrode on the first current collector foil roll made of a conductor with a first coating width;
Applying the electrode layer material of the negative electrode on the second current collector foil roll made of a conductor with a second coating width wider than the first coating width;
Punching out the positive electrode from the first current collector foil roll coated with the electrode layer material;
Punching out the negative electrode from the second current collector foil roll coated with the electrode layer material;
A method of manufacturing a power storage device, comprising: placing the punched positive electrode and the punched negative electrode facing each other.

Images