JP2017168634A - Electrode for electrochemical device, electrochemical device, method for manufacturing electrode for electrochemical device, and method for manufacturing electrochemical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for an electrochemical device capable of suppressing short-circuit defects between electrodes due to burrs and debris, an electrochemical device, a method for manufacturing an electrode for an electrochemical device, and a method for manufacturing an electrochemical device.SOLUTION: An electrode 21 for an electrochemical device includes: a current collector foil 211; and active material layers 212, 213. The current collector foil is a current collector foil made of a porous metal and having a first main surface 211a and a second main surface 211b opposite to the first main surface, and is provided at the peripheral edge of the current collector foil with a first region 211c having a first thickness and a second region 211d having a second thickness larger than the first thickness. The active material layer is formed on the first main surface.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electrode for an electrochemical device having a current collector foil and an active material layer, an electrochemical device, a method for producing an electrode for an electrochemical device, and a method for producing an electrochemical device.

  In general, an electrochemical device such as a lithium ion capacitor, an electric double layer capacitor, or a lithium ion secondary battery is configured such that a positive electrode and a negative electrode face each other through a separator and are sealed together with an electrolytic solution. When a voltage is applied between the positive electrode and the negative electrode, charges are accumulated on the positive electrode and the negative electrode. The electrodes (positive electrode and negative electrode) are generally those in which an electrode layer containing an active material such as activated carbon is laminated on a current collector such as a metal foil.

  Here, in such an electrochemical device, burrs and burrs may be generated during the manufacturing process. As a result, there is a problem in that the positive and negative electrodes are conducted through the burr and burr scrap and a short circuit failure occurs.

  Therefore, in order to solve such a problem, for example, Patent Document 1 describes that it is difficult to generate burrs in the current collector foil by managing gap adjustment and the like of the electrode cutting device.

  Patent Document 2 describes that the generated burrs are crushed so that the burrs generated by cutting the tabs do not damage the electrodes and the separator.

  Further, Patent Document 3 describes that a burr generated on an electrode sheet can be prevented from breaking through the separator by folding the separator to form a multilayer structure.

Japanese Patent Application Laid-Open No. 08-096803 JP 2005-251709 A Japanese Patent Laid-Open No. 2001-282897

  However, even if the techniques described in Patent Documents 1 to 3 are used, depending on the material of the current collector foil, burrs may be generated in the current collector foil during the manufacturing process of the electrochemical device, or the burrs may be removed to generate burrs. May occur. This may cause a short circuit failure between the electrodes due to burrs and burrs.

  In view of the circumstances as described above, an object of the present invention is to provide an electrode for an electrochemical device, an electrochemical device, a method for producing an electrode for an electrochemical device, and a production of an electrochemical device capable of suppressing a short circuit failure between electrodes. It aims to provide a method.

In order to achieve the above object, an electrode for an electrochemical device according to one embodiment of the present invention includes a current collector foil and a first active material layer.
The current collector foil is a current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, and is provided at the periphery of the current collector foil A first region having a first thickness and a second region having a second thickness greater than the first thickness.
The first active material layer is formed on the first main surface.

According to this configuration, the current collector foil has a first region having a first thickness at the periphery and a second region having a second thickness greater than the first thickness inside the periphery. Thereby, in the electrochemical device in which the first region faces the electrode via the separator, a predetermined distance is ensured between the first region and the electrode.
Therefore, even if burrs are formed in the first region or burrs are attached to the first active material layer on the first region, conduction between the electrodes through the burrs and burrs Is suppressed.
Therefore, the electrochemical device having the electrode of the present invention can have a configuration in which occurrence of a short circuit failure between the electrodes is prevented.

  The electrode for an electrochemical device may further include a second active material layer formed on the second main surface.

  Thereby, the capacity | capacitance of an electrochemical device can be enlarged compared with the case where the active material layer is formed only in one surface of current collection foil.

The first region is a region where the porous metal is compressed,
The second region may be a region where the porous metal is not compressed.

  As a result, the current collector foil in the first region is densified and hardened, and the generation of burrs and debris from the current collector foil is suppressed.

  The porous metal may be porous aluminum.

  As a result, the current collector foil in the first region has a higher density than when a plain foil is used for the current collector foil. Therefore, the formation of burrs on the cut surface of the electrode and the generation of burrs are more effectively suppressed.

The first active material layer is provided on the first region, has a third region having a third thickness, and is provided on the second region, and has a fourth thickness greater than the third thickness. A fourth region having a thickness of
The second active material layer is provided on the first region, has a fifth region having a fifth thickness, and is provided on the second region, and has a sixth thickness greater than the fifth thickness. And a sixth region having a thickness of.

  The third region has a higher density and higher hardness than the fourth region, and the fifth region has a higher density and higher hardness than the sixth region. Thereby, slipping and powdering off of the active material layer from the current collector foil are suppressed, and the reliability of the electrochemical device is improved.

  The first thickness may be not less than 60% and not more than 95% with respect to the second thickness.

  Thereby, the electrochemical device according to the present invention has a configuration in which short circuit defects due to burrs and burrs are suppressed while a desired capacitance is secured.

In order to achieve the above object, an electrochemical device according to an embodiment of the present invention includes an electrode and a separator.
The electrode is a current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, and is provided on the periphery of the current collector foil A current collector foil having a first region having a first thickness and a second region having a second thickness that is spaced apart from the periphery of the current collector foil and is greater than the first thickness; A first active material layer formed on the main surface and a second active material layer formed on the second main surface.
The separator is laminated on the electrode.

  The electrochemical device has a configuration in which electrodes having a first thickness smaller than the second thickness are opposed to each other via a separator at the periphery. Thereby, as shown in the figure, a predetermined distance is ensured between the first region of one electrode and the first region of the other electrode.

  Therefore, even if burrs are formed in the first region, or even if burrs are attached to the first and second active material layers on the first region, the gaps between the electrodes through the burrs and burrs Is suppressed. That is, it is possible to suppress the occurrence of short-circuit defects due to burrs and burrs.

  The electrochemical device may further include a second active material layer formed on the second main surface.

  Thereby, the capacity | capacitance of an electrochemical device can be enlarged compared with the case where the active material layer is formed only in one surface of current collection foil.

In order to achieve the above object, a method for producing an electrode for an electrochemical device according to an aspect of the present invention comprises:
A current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, and a first active material layer formed on the first main surface And prepare an electrode sheet comprising
Pressing a partial region of the electrode sheet from a direction perpendicular to the first main surface and the second main surface to form a press region on the electrode sheet;
The electrode sheet is separated by cutting the press area to form an electrode.

  According to this manufacturing method, a press area is formed on the electrode sheet. Thereby, the current collection foil in a press area | region is densified and high-hardened. Therefore, by setting the cut portion of the electrode sheet as a press region, the generation of burrs, debris, and the like accompanying the cutting of the electrode sheet is suppressed.

  In the step of preparing the electrode sheet, an electrode sheet including the current collector foil, the first active material layer, and a second active material layer formed on the second main surface may be prepared. Good.

  Thereby, the capacity | capacitance of an electrochemical device can be enlarged compared with the case where the active material layer is formed only in one surface of current collection foil.

  The porous metal may be porous aluminum.

  As a result, the current collector foil in the first region has a higher density than when a plain foil is used for the current collector foil. Therefore, the formation of burrs on the cut surface of the electrode and the generation of burrs are more effectively suppressed.

  In the step of pressing the electrode sheet, the electrode sheet may be pressed with a load at which the thickness of the current collector foil in the press region is 60% or more and 95% or less compared to before pressing.

  As a result, it is possible to manufacture an electrochemical device in which short-circuit defects due to burrs and burrs are suppressed while a desired capacitance is ensured.

  In the step of pressing the electrode sheet, a first press die for pressing the electrode sheet from the first active material layer side, and a second press for pressing the electrode sheet from the second active material layer side You may press the said electrode sheet simultaneously with a type | mold.

In the step of pressing the electrode sheet,
You may press the said electrode sheet with the press type | mold which presses the said electrode sheet from the said 1st active material layer side.

The step of pressing the electrode sheet includes:
A first pressing step of pressing the electrode sheet with a first press die for pressing the electrode sheet from the first active material layer side;
And a second pressing step of pressing the electrode sheet with a second press die that presses the electrode sheet from the second active material layer side.

In order to achieve the above object, a method for producing an electrochemical device according to an aspect of the present invention includes:
A current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, the first thickness provided at the periphery of the current collector foil A current collector foil having a first region having a first thickness and a second region having a second thickness larger than the first thickness and spaced from the periphery of the current collector foil; and on the first main surface Preparing an electrode comprising the formed first active material layer;
A power storage element is formed by laminating the electrode and the separator,
The above electricity storage element is accommodated in an exterior body and immersed in an electrolytic solution.

  According to this manufacturing method, the electrochemical device according to the present invention is manufactured by forming a power storage element with the electrode and the separator, housing the power storage element in the exterior body, and immersing it in the electrolytic solution. Thereby, the electrochemical device which cannot produce the short circuit defect resulting from a burr | flash or a burr | flash waste can be manufactured.

  In the step of preparing the electrode, an electrode including the current collector foil, the first active material layer, and a second active material layer formed on the second main surface may be prepared.

  Thereby, the capacity | capacitance of an electrochemical device can be enlarged compared with the case where the active material layer is formed only in one surface of current collection foil.

  As described above, according to the present invention, it is possible to provide an electrode for an electrochemical device, an electrochemical device, a method for manufacturing an electrode for an electrochemical device, and a method for manufacturing an electrochemical device that can suppress a short circuit failure between electrodes. .

1 is a perspective view of an electrochemical device according to an embodiment of the present invention. It is sectional drawing of the same electrochemical device. It is an expanded sectional view of the electrode with which the same electrochemical device is provided. It is a top view of the electrode. It is an expanded sectional view of the electrical storage element which concerns on the embodiment which shows the edge part of the electrode. It is a schematic diagram which shows the manufacturing process of the electrochemical device which concerns on embodiment of this invention. It is a schematic diagram which shows the manufacturing process of the same electrochemical device. It is a schematic diagram which shows the manufacturing process of the electrochemical device which concerns on the other manufacturing method of the embodiment. It is a schematic diagram which shows the manufacturing process of the same electrochemical device. It is a schematic diagram which shows the manufacturing process of the electrochemical device which concerns on the comparative example of this invention. It is sectional drawing of the electrode sheet which concerns on the comparative example of this invention. It is a schematic diagram of the electrical storage element which concerns on the comparative example of this invention. It is a schematic diagram of the electrical storage element which concerns on embodiment of this invention. It is an expanded sectional view of the electrode which concerns on the modification of this invention. It is a table | surface which shows the result of having investigated the number of the burr | flash produced | generated with the electrode which concerns on the Example and comparative example of this invention, and a burr | flash waste.

[Configuration of electrochemical device]
FIG. 1 is a perspective view of an electrochemical device 10 according to the present embodiment, and FIG. 2 is a cross-sectional view of the electrochemical device 10 taken along line AA in FIG. In the following drawings, the X, Y, and Z directions are three directions orthogonal to each other.

  As shown in FIGS. 1 and 2, the electrochemical device 10 includes a power storage element 20, an electrode terminal 30, and an exterior body 40.

  As shown in FIG. 2, the electricity storage element 20 includes an electrode 21 and a separator 22. The electrode 21 is opposed to the other electrode 21 through the separator 22 as shown in FIG. The electrode 21 functions as a positive electrode or a negative electrode of the electrochemical device 10.

  FIG. 3 is an enlarged cross-sectional view of the electrode 21, and FIG. 4 is a plan view of the electrode 21. As illustrated in FIG. 3, the electrode 21 includes a current collector foil 211, a first active material layer 212, and a second active material layer 213.

  As shown in FIGS. 3 and 4, the current collector foil 211 has a first region 211c (a region indicated by a dot pattern in FIG. 4) having a first thickness D1 at the periphery, and a second region inside the periphery separated from the periphery. A second region 211d having a thickness D2 is provided. The first region 211c is a region where the current collector foil 211 is compressed in the Z direction, and the second region 211d is a region where the current collector foil 211 is not compressed.

  Here, as shown in FIG. 3, the second thickness D2 is configured to be thicker than the first thickness D1, and the ratio of the first thickness D1 to the second thickness D2 is preferably 60% or more and 95% or less. It is.

  The current collector foil 211 is a porous metal foil having conductivity and having a large number of through holes. Specifically, the current collector foil 211 is a foil made of a porous metal such as aluminum, copper, nickel, or stainless steel, and a porous aluminum foil is particularly preferable. The current collector foil 211 may be a metal foil whose surface is chemically or mechanically roughened.

  As shown in FIG. 3, the first active material layer 212 is formed on the first main surface 211 a of the current collector foil 211. In addition, as shown in the drawing, the first active material layer 212 is provided on the first region 211c, provided on the third region 212a having the third thickness D3, and the second region 211d, and the fourth region 211c. And a fourth region 212b having a thickness D4. As shown in FIG. 3, the fourth thickness D4 is configured to be thicker than the third thickness D3.

  As shown in FIG. 3, the second active material layer 213 is formed on the second main surface 211 b of the current collector foil 211. In addition, as shown in the drawing, the second active material layer 213 is provided on the first region 211c, provided on the fifth region 213a having the fifth thickness D5, and on the second region 211d. And a sixth region 213b having a thickness D6. As shown in FIG. 3, the sixth thickness D6 is configured to be thicker than the fifth thickness D5.

  The first and second active material layers 212 and 213 include an electrode active material, a binder resin, and a conductive additive. The electrode active material is, for example, non-graphitizable carbon (hard carbon), graphite, soft carbon, activated carbon or polyacene carbide.

  Examples of the binder resin include styrene butadiene rubber, polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, carboxymethyl cellulose, fluorine-based rubber, polyvinylidene fluoride, isoprene rubber, butadiene rubber, and ethylene-propylene rubber.

  The conductive auxiliary agent is a particle made of a conductive material, and improves the conductivity between the electrode active materials. The conductive aid is, for example, a carbon-based material such as graphite or carbon black. These may be single and multiple types may be mixed. The conductive auxiliary agent may be a metal material or a conductive polymer as long as it is a conductive material.

  As shown in FIG. 2, the separator 22 is disposed between one electrode 21 and the other electrode 21, and allows the electrolytic solution to pass therethrough and prevents contact (conduction) between the electrodes 21. The separator 22 is, for example, a woven fabric, a nonwoven fabric, or a synthetic resin microporous film.

  The kind of power storage element 20 is not particularly limited, and can be, for example, a lithium ion capacitor, a lithium ion battery, or an electric double layer capacitor.

  The electrode terminal 30 is an external terminal of the electrode 21. The electrode terminal 30 is electrically connected to the electrode 21 via the wiring L as shown in FIG. 2, and is drawn out through the space between the two exterior films 40a. The electrode terminal 30 is, for example, a foil or a wire made of a conductive material. The electrode terminal 30 may be directly connected to the electrode 21 without using the wiring L.

  As shown in FIG. 2, the exterior body 40 is composed of two exterior films 40 a, and houses and seals the power storage element 20 and the electrolytic solution. The two exterior films 40a are sealed at the periphery of the electricity storage element 20, as shown in the figure.

  The exterior film 40a is a sheet-like material made of a conductive material, and for example, an aluminum laminate material is employed. Moreover, in this embodiment, it may replace with the exterior body 40 and the case etc. which consist of synthetic resins may be utilized.

The electrolyte solution accommodated in the outer package 40 is not particularly limited as long as it is an ionic liquid containing an anion and a cation. Specifically, in the electrolyte solution according to the present embodiment, BP · BF ₄ (5-azoniaspiro [4.4] nonanetetrafluoroborate), LiBF ₄ or LiPF ₆ or the like is used as an electrolyte, and a solvent (carbonate ester or the like). A solution or the like dissolved in is used.

  The electrochemical device 10 according to the present embodiment has the above configuration. In addition, the electrochemical device 10 is not limited to the structure shown in FIGS. For example, the electrochemical device 10 may be composed of a single exterior film in which the exterior body 40 is continuous.

[Effects of electrochemical devices]
FIG. 5 is an enlarged cross-sectional view of the storage element 20 showing the end of the electrode 21. The electrochemical device 10 has a configuration in which current collecting foils 211 having a first thickness D1 thinner than a second thickness D2 are opposed to each other via a separator 22 at a peripheral edge (end portion) as shown in FIG. It is. Thereby, as shown in FIG. 5, a predetermined distance D <b> 7 is ensured between the first region 211 c of one electrode 21 and the first region 211 c of the other electrode 21.

  Therefore, in the electrochemical device 10 according to the present embodiment, burrs are formed in the first region 211c, or burrs and the like are attached to the first and second active material layers 212 and 213 on the first region 211c. Even if it does, the conduction | electrical_connection between the electrodes 21 through the said burr | flash or burr | flash waste will be suppressed. Therefore, it is possible to suppress a short circuit failure between the electrodes 21.

  In particular, by setting the first thickness D1 in the range of 60% or more and 95% or less with respect to the second thickness D2, the electrochemical device 10 can achieve the desired capacitance as described above. The short circuit failure between the electrodes 21 due to burrs and burrs is suppressed.

[Method of manufacturing electrochemical device]
A method for manufacturing the electrochemical device 10 according to the present embodiment will be described. In addition, the manufacturing method shown below is an example and the electrochemical device 10 can also be manufactured by a manufacturing method different from the manufacturing method shown below. 6 and 7 are schematic views showing the manufacturing process of the electrochemical device 10.

  First, as shown to Fig.6 (a), the porous metal foil 221 in which the through-hole used as the origin of the current collection foil 211 is formed is prepared. The thickness of the porous metal foil 221 is not particularly limited, but can be several tens of μm to several hundreds of μm. In addition, the porous metal foil 221 which concerns on this embodiment is a porous aluminum foil, for example.

  Next, an electrode paste (slurry) containing an electrode active material, a binder, and a conductive additive is applied to the front surface 221a and the back surface 221b of the porous metal foil 221, and dried or cured. As a result, as shown in FIG. 6B, an electrode sheet 230 is obtained in which the first active material layer 222 is formed on the front surface 221a and the second active material layer 223 is formed on the back surface 221b.

  Subsequently, as shown in FIG. 6C, the first press die P1 disposed on the first active material layer 222 side along the direction perpendicular to the front surface 221a and the back surface 221b (thickness direction of the electrode sheet 230) and The electrode sheet 230 is simultaneously pressed using the second press die P2 arranged on the second active material layer 223 side. Thereby, as shown to Fig.7 (a), the press area | region 230a is formed in the electrode sheet 230. FIG.

  Subsequently, as shown in FIG. 7B, the electrode sheet 230 is separated by cutting the press region 230 a of the electrode sheet 230 with a cutting machine C. As a result, as shown in FIG. 7C, an electrode 210 is obtained in which a first region 210a is formed at the periphery and a second region 210b is formed inside the periphery spaced from the periphery.

  Next, the electrode 210 is stacked with a separator interposed therebetween, thereby forming a power storage element. Subsequently, the electrode terminal and the electrode 210 are electrically connected through the wiring L, and the power storage element connected to the electrode terminal is accommodated in the exterior body. Next, the electrochemical device 10 is obtained by injecting and sealing the electrolytic solution into the housing space that is partitioned by the exterior body and that houses the power storage element.

  The electrochemical device 10 can be manufactured as described above. The electrode 210 corresponds to the electrode 21, the porous metal foil 221 corresponds to the current collector foil 211, the front surface 221a corresponds to the first main surface 211a, and the back surface 221b corresponds to the second main surface 211b. The first active material layer 222 corresponds to the first active material layer 212, and the second active material layer 223 corresponds to the second active material layer 213.

  Further, the first region 210a corresponds to the first region 211c, the third region 212a, and the fifth region 213a, and the second region 210b corresponds to the second region 211d, the fourth region 212b, and the sixth region 213b.

(Other manufacturing methods)
8 and 9 are schematic views showing a manufacturing process of the electrochemical device 10 according to another manufacturing method of the present embodiment. In the method for manufacturing the electrochemical device 10, as shown in FIGS. 6C and 7A, the electrode sheet 230 is simultaneously pressed using the first and second press dies P 1 and P 2, thereby Although the press area 230a is formed on the sheet 230, the present invention is not limited to this. For example, as shown in FIG. 8, the press region 230a may be formed by pressing the electrode sheet 230 from the first active material layer 222 side by a single press die P3.

  Further, the method of forming the press region 230a on the electrode sheet 230 is not limited to the above manufacturing method, and after either one of the first and second press dies P1 and P2 presses the electrode sheet 230. The press region 230a may be formed by pressing the electrode sheet 230 with the other press die.

  In addition, the method of separating the electrode sheet 230 is not limited to the above manufacturing method. As shown in FIG. 8, the press region 230a of the electrode sheet 230 formed by pressing the press die P3 has the same shape as the press region 230a. The electrode sheet 230 may be separated by punching using the punching die U.

  Alternatively, as shown in FIG. 9, while the electrode sheet 230 is being conveyed, the press area 230a is formed by the roll-shaped cutting machine C while the press area 230a is formed on the electrode sheet 230 by the roll-shaped press machine P4. Therefore, the electrode sheet 230 may be separated. Thereby, it becomes possible to manufacture a strip-shaped electrode used in a wound electrochemical device.

[Effects in electrochemical device manufacturing method]
The effect in the manufacturing method of the electrochemical device 10 will be described using a comparative example. FIG. 10 is a schematic view showing a manufacturing process of an electrochemical device according to a comparative example, and FIG. 11 is a cross-sectional view of an electrode sheet according to the comparative example. 12 is a schematic diagram of a power storage element according to a comparative example, and FIG. 13 is a schematic diagram of a power storage element according to the present embodiment.

  In the manufacturing method of the electrochemical device so far, the electrode sheet 330 is cut using the cutting machine C as shown in FIG. 10 (a), or the punching die U is used as shown in FIG. 10 (b). It is cut by press working. As a result, as shown in FIG. 11, burrs B1 may be generated on the cut surface S of the electrode sheet 330, or burrs B1 may be peeled off from the metal foil 311 to generate burrs B2.

  Therefore, when such an electrode 310 is stacked via a separator to form a storage element 340 as shown in FIG. 10, the burr B1 formed on the cut surface S of the electrode 310 breaks through the separator, As shown in FIG. 10, when the burr scrap B2 is transferred to the other electrode 310 facing each other through the separator, a short circuit failure between the electrodes 310 may occur.

  On the other hand, in the method for manufacturing the electrochemical device 10 according to the present embodiment, the press region 230a is formed in the electrode sheet 230 as shown in FIG. Thereby, the porous metal foil 221 in the press area 230a is increased in density and hardness. Therefore, by setting the cut portion of the electrode sheet 230 as the press region 230a, the generation of burrs, debris and the like accompanying the cutting of the electrode sheet 230 is suppressed.

  In particular, by setting the metal foil of the electrode sheet 230 to the porous metal foil 221, the metal foil in the press region 230a is densified more than when a plain foil is used for the metal foil. Therefore, it is possible to more effectively suppress the formation of burrs on the cut surface of the electrode 210 and the generation of burrs.

  Therefore, even if the electrode 21 according to the present embodiment is laminated through the separator and the power storage device 20 is configured as shown in FIG. 13, the burr breaks through the separator as shown in FIG. The transfer of burr dust to the electrode 21 on the formed side is suppressed.

  Moreover, in this embodiment, when forming the press area | region 230a in the electrode sheet 230, the load from which the thickness of the porous metal foil 221 in the press area | region 230a becomes 60% or more and 95% or less compared with the thickness before a press. Thus, it is preferable to press the electrode sheet 230. As a result, it is possible to manufacture the electrochemical device 10 in which generation of burrs, burrs, and the like is suppressed while a desired capacitance is ensured.

  If the thickness of the porous metal foil 221 in the press region 230a is 60% or less as compared with the thickness before pressing, the durability of the electrode sheet 230 is reduced, and bending or the like is likely to occur. On the other hand, if it exceeds 95%, the porous metal foil 221 in the press region 230a is not densified so much that it is difficult to suppress the generation of burrs and burr debris derived from the porous metal foil 221.

  Furthermore, the electrode sheet 230 has a configuration in which not only the porous metal foil 221 but also the first and second active material layers 222 and 223 in the press region 230a have high density and high hardness by forming the press region 230a. It becomes. Thereby, when the electrode sheet 230 is cut, the first and second active material layers 222 and 223 can be prevented from slipping or falling off from the porous metal foil 221.

[Modification]
The configuration with the electrode 21 according to the present embodiment is not limited to the above. FIG. 14 is an enlarged cross-sectional view of an electrode 21 according to a modification.

  In the above embodiment, the electrode 21 has a configuration in which the first active material layer 212 is formed on the first main surface 211a of the current collector foil 211 and the second active material layer 213 is formed on the second main surface 211b. However, the present invention is not limited to this, and the first active material layer 212 may be formed only on the first main surface 211a as shown in FIG.

  Electrodes for electrochemical devices (hereinafter referred to as electrodes) according to Examples and Comparative Examples of the present invention were produced, and the amount of burrs and burr waste generated was examined.

[Production of electrodes]
Example 1
The electrode was produced as follows. First, a double-sided electrode having electrode layers coated on both sides of a porous current collector foil was pressed from both sides with a press head to form a compression portion on the porous current collector foil (see FIG. 7A). Since the porous current collector foil was sponge-like and contained voids, the voids were crushed and thinned by pressurization.

  Here, in Example 1, when the thickness of the uncompressed portion was set to 100%, the pressing was performed at such a pressure that the thickness of the compressed portion became 70%. As shown in FIG. 12, the press head was provided with a 45 ° taper in order to prevent the electrode layer from cracking by setting the width of the flat portion at the tip to 1 mm.

  Next, an electrode was obtained by cutting a portion where the double-sided electrode including the compression part was compressed and separating the double-sided electrode. At this time, the position of the cutting blade was adjusted so that the middle of the flat width in the compression portion was cut (see FIG. 7B).

(Example 2)
The electrode according to Example 2 was manufactured in the same manner as in Example 1 except for the differences from Example 1 described below.

  Differences from the first embodiment are as follows. That is, in Example 2, the compression part was formed in the porous collector foil by operating a press die having the same shape as the punching die and pressing the double-sided electrode. Next, the stage was moved, and the punching die was operated at the same position as the press die as shown in FIG.

(Example 3)
The electrochemical device according to Example 3 was manufactured in the same manner as in Example 1 except for the point different from Example 1 described below.

  Differences from the first embodiment are as follows. That is, in Example 3, the compression part was formed by partially pressing with a roller upstream of the conveyance direction of the double-sided electrode. And the electrode was obtained by cut | disconnecting a press location (compression part) with a slit cut blade downstream in the conveyance direction of a double-sided electrode (refer FIG. 9).

(Comparative example)
Next, electrodes according to Comparative Examples 1 and 2 were produced. The electrode according to Comparative Example 1 was produced in the same manner as the electrochemical device according to Example 1 except that the compression part was not formed on the current collector foil (see FIG. 10A).

  The electrochemical device according to Comparative Example 2 is manufactured in the same manner as the electrochemical device according to Example 2 except that a compression part is formed on the current collector foil by using a press die having the same shape as the punching die. (See FIG. 10B).

[Research]
Next, 10 electrodes each having a size of 100 mm × 100 mm according to Examples and Comparative Examples were prepared, and the number of burrs and burrs generated on the electrodes was examined. Specifically, use a microscope to check how many of each electrode have a size exceeding 30 μm that breaks through the separator, a range of 15 to 30 μm that breaks through a thin separator, and a size of 15 μm or less. did. FIG. 15 is a table showing the results. In addition, the numerical value (number) described in FIG. 15 is an average value of the number of burrs and burrs confirmed in each of the 10 electrodes.

  As shown in FIG. 15, the electrode according to Comparative Example 1 had no burrs or burrs of 15 μm or less, but burrs and burrs in the size range of 15 to 30 μm, and burrs and burrs of more than 30 μm Many were confirmed. Such burrs and burrs are burrs and burrs derived from the current collector foil generated when the double-sided electrode is cut (see FIG. 11).

  Therefore, if the electrode according to Comparative Example 1 is stacked through the separator to form the power storage device, the above-described burrs and burrs may break through the separator and cause a short circuit failure.

  As shown in FIG. 15, the electrode according to Comparative Example 2 has more burrs and burrs having a size in the range of 15 to 30 μm, and more burrs and burrs than 30 μm, as compared with the electrode according to Comparative Example 1. It was. Similar to Comparative Example 1, such burrs and burrs are also burrs and burrs derived from the current collector foil generated when the double-sided electrodes are punched out.

  Therefore, if an electrical storage element is configured using the electrode according to Comparative Example 2, the burr scraps are transferred to the stacked electrode, and a short circuit failure may occur (see FIG. 12). Therefore, in order to manufacture an electrochemical device using the electrode according to Comparative Example 2, a step of removing burrs and debris is necessary, and productivity is reduced.

  On the other hand, as shown in FIG. 15, the electrodes according to Examples 1 and 2 are reduced in the generation of burrs and debris and reduced in size as compared with the electrodes according to Comparative Examples 1 and 2. Was confirmed. It was also confirmed that the cut surface of the current collector foil was in a clean state as if the plain foil was cut.

  Thereby, it can be said that the manufacturing method of the electrode which concerns on Example 1 and 2 is a method which can suppress that a burr | flash and a burr | flash scrap generate | occur | produce in an electrode. Therefore, even if it comprises an electrical storage element using the electrode which concerns on Examples 1-3, generation | occurrence | production of the short circuit defect like the comparative examples 1 and 2 is suppressed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, A various change can be added.

  For example, although the laminated film type electrochemical device has been described as an example of the electrochemical device 10 in the above embodiment, the present invention can also be applied to a wound type electrochemical device.

DESCRIPTION OF SYMBOLS 10 ... Electrochemical device 20 ... Electric storage element 21 ... Electrode 22 ... Separator 30 ... Electrode terminal 40 ... Exterior body 211 ... Current collecting foil 211a First main surface 211b ... Second main surface 212 ... first active material layer 213 ... second active material layer 211c ... first region 211d ... second region 212a ... third region 212b ...・ Fourth region 213a ・ ・ Fifth region 213b ・ ・ Sixth region

Claims (17)

A current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, the first thickness provided at the periphery of the current collector foil A current collector foil comprising: a first region having a second region having a second thickness greater than the first thickness;
An electrode for an electrochemical device, comprising: a first active material layer formed on the first main surface. The electrode for an electrochemical device according to claim 1,
An electrode for an electrochemical device, further comprising a second active material layer formed on the second main surface. The electrode for an electrochemical device according to claim 2,
The first region is a region where the porous metal is compressed,
The electrode for an electrochemical device, wherein the second region is a region where the porous metal is not compressed. The electrode for an electrochemical device according to claim 2,
The electrode for an electrochemical device, wherein the porous metal is porous aluminum. The electrode for an electrochemical device according to claim 2,
The first active material layer is provided on the first region, has a third region having a third thickness, and is provided on the second region, and has a fourth thickness greater than the third thickness. A fourth region having a thickness of
The second active material layer is provided on the first region, has a fifth region having a fifth thickness, and is provided on the second region, and has a sixth thickness greater than the fifth thickness. Electrode for electrochemical devices which has 6th area | region which has thickness of these. The electrode for an electrochemical device according to claim 2,
The electrode for an electrochemical device, wherein the first thickness is 60% to 95% with respect to the second thickness. A current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, the first thickness provided at the periphery of the current collector foil A current collector foil having a first region having a first thickness and a second region having a second thickness larger than the first thickness and spaced from a peripheral edge of the current collector foil; and An electrode comprising a first active material layer formed;
An electrochemical device comprising: a separator laminated on the electrode. The electrochemical device according to claim 7,
An electrochemical device further comprising a second active material layer formed on the second main surface. A current collector foil made of porous metal and having a first main surface and a second main surface opposite to the first main surface, and a first active material layer formed on the first main surface And prepare an electrode sheet comprising
Pressing a partial region of the electrode sheet from a direction perpendicular to the first main surface and the second main surface to form a press region on the electrode sheet;
A method for producing an electrode for an electrochemical device, wherein the electrode sheet is separated by cutting the press region to form an electrode. A method for producing an electrochemical device according to claim 9,
In the step of preparing the electrode sheet, an electrode sheet including the current collector foil, the first active material layer, and a second active material layer formed on the second main surface is prepared. A method for manufacturing an electrode for a device. A method for producing an electrode for an electrochemical device according to claim 10,
The said porous metal is a porous aluminum The manufacturing method of the electrode for electrochemical devices. A method for producing an electrode for an electrochemical device according to claim 10,
In the step of pressing the electrode sheet, the electrode sheet is pressed with a load in which the thickness of the current collector foil in the press region is 60% or more and 95% or less compared with that before pressing. Method. A method for producing an electrode for an electrochemical device according to claim 10,
In the step of pressing the electrode sheet, a first press die that presses the electrode sheet from the first active material layer side and a second press that presses the electrode sheet from the second active material layer side A method for producing an electrode for an electrochemical device, wherein the electrode sheet is simultaneously pressed by a mold. A method for producing an electrode for an electrochemical device according to claim 10,
In the step of pressing the electrode sheet,
The manufacturing method of the electrode for electrochemical devices which presses the said electrode sheet with the press type | mold which presses the said electrode sheet from the said 1st active material layer side. A method for producing an electrode for an electrochemical device according to claim 10,
The step of pressing the electrode sheet includes:
A first pressing step of pressing the electrode sheet with a first press die that presses the electrode sheet from the first active material layer side;
And a second pressing step of pressing the electrode sheet with a second press die that presses the electrode sheet from the second active material layer side. A current collector foil made of a porous metal and having a first main surface and a second main surface opposite to the first main surface, the first thickness provided at the periphery of the current collector foil A current collector foil having a first region having a first thickness and a second region having a second thickness larger than the first thickness and spaced from a peripheral edge of the current collector foil; and Preparing an electrode comprising the formed first active material layer;
By alternately laminating the electrodes and separators to form a storage element,
A method for producing an electrochemical device, wherein the power storage element is housed in an exterior body and immersed in an electrolytic solution. A method for producing an electrochemical device according to claim 16,
In the step of preparing the electrode, an electrode including the current collector foil, the first active material layer, and a second active material layer formed on the second main surface is prepared. Production method.

Images