JP6260860B2 - Electrolytic aluminum foil, battery electrode and storage device using the same, and method for producing electrolytic aluminum foil - Google Patents

Description

  The present invention relates to an electrolytic aluminum foil obtained by an electrolysis method, a battery electrode using the same, an electricity storage device, and a method for producing the electrolytic aluminum foil.

Aluminum foil is used as one member of an electrode of an electricity storage device. An electrode of an electricity storage device such as a lithium ion secondary battery (LIB), an electric double layer capacitor (EDLC), or a lithium ion capacitor (LIC) is used by being immersed in an organic electrolyte. For example, the electrode has a structure in which an active material such as LiMn ₂ O ₄ (lithium manganate), LiCoO ₂ (lithium cobaltate) or activated carbon is fixed to a current collector made of an aluminum foil.

  The aluminum foil is generally produced by rolling, but most of the thickness is greater than 20 μm. When an aluminum foil is used as an electrode for an electricity storage device, the thinner the foil, the higher the energy density of the electricity storage device. Therefore, a thinner aluminum foil has been demanded. However, in the manufacturing method by rolling, the above-mentioned thickness is the limit that can be reduced in mass production.

  As a method for producing a thin aluminum foil of 20 μm or less, a method of producing an electrolytic aluminum foil by a method (electrolytic method) of depositing aluminum by electrolytic reduction from an electrolytic solution containing aluminum ions is known. For example, as described in Patent Document 1, an electrolytic aluminum foil in which a cathode drum and an anode plate are arranged to face each other via an aluminum electrolytic solution in which at least an aluminum halide is dissolved in alkylsulfone, and a power source is connected between both electrodes. There are manufacturing equipment. There is known a method of energizing this apparatus and depositing an aluminum film as a foil on the peripheral surface of the cathode drum while rotating the cathode drum, and immediately peeling it to obtain an electrolytic aluminum foil continuously.

  In addition, it is known that surface roughness should be considered when using a metal foil as a current collector for an electricity storage device. Patent Document 2 describes means for roughening the surface by injecting alumina particles onto the surface of an aluminum foil used as a current collector, whereby when the electrode active material is applied to the aluminum foil, the adhesion between the two is achieved. It is described that the property can be improved as compared with the conventional case, and as a result, an increase in contact resistance can be suppressed.

JP 2012-246561 A JP 11-162470 A

  The electrolytic aluminum foil used for the electricity storage device is usually flat on the electrode side and rough on the deposition side. As it is, there is a problem in that the battery characteristics of the front and back sides are different and the charge / discharge efficiency of the electricity storage device is not stabilized.

  Therefore, the present invention provides an electrolytic aluminum foil that solves the above problems, can be continuously manufactured, and can stabilize the charge and discharge efficiency. Moreover, it aims at providing the electrode for batteries using the same, and an electrical storage device. Moreover, the manufacturing method for obtaining continuously the electrolytic aluminum foil in which both surfaces were roughened to the same extent is provided.

The present invention applies a current between a cathode drum partially immersed in a plating solution for forming a foil and an anode plate, forms an aluminum electrolytic film on the cathode drum, and then peels off the substrate peeling surface and the deposited material. In the method for producing an aluminum foil having a surface, when the aluminum electrolytic membrane is formed, the surface roughness Ra of the cathode drum is set to 0.1 μm or more and 0.6 μm or less so that the roughness Ra of the substrate peeling surface is 0. By making the applied current under the condition of 0.25 A / dm ² or more and 20 A / dm ² or less in the range of 1 μm or more and 0.6 μm or less, and forming the aluminum electrolytic membrane to a thickness of 5 μm or more and 25 μm or less The roughness Ra of the precipitation surface is in the range of 0.1 μm or more and 0.6 μm or less, and the difference between the roughness Ra of the substrate peeling surface and the precipitation surface is 0.2 μm or less.
The foil forming plating solution to be used preferably contains at least (1) a dialkyl sulfone, (2) an aluminum halide, and (3) a nitrogen-containing compound.
The nitrogen-containing compound used is ammonium halide, hydrogen halide salt of primary amine, hydrogen halide salt of secondary amine, hydrogen halide salt of tertiary amine, general formula: R ¹ R ² R ³ R ⁴ N · A quaternary ammonium salt represented by X (R ^{1 to} R ⁴ are the same or different alkyl groups, X represents a counter anion with respect to a quaternary ammonium cation), at least one selected from the group consisting of nitrogen-containing aromatic compounds; It is preferable to do.

According to the present invention, it is possible to provide an electrolytic aluminum foil that can be continuously manufactured and whose both surfaces are roughened to the same extent. By using this electrolytic aluminum foil for an electricity storage device, it is possible to provide a battery with stable discharge / charge efficiency. Moreover, since this electrolytic aluminum foil can be manufactured by a simple process that does not require blasting or etching for injecting alumina particles, manufacturing cost can be reduced.
Moreover, the manufacturing method for obtaining easily the electrolytic aluminum foil which was thin and roughened to the same extent on both surfaces can be provided.

It is a figure which shows the relationship between the surface roughness Ra of a cathode drum, and the roughness Ra of the back surface of an electrolytic aluminum foil. It is a figure which shows the relationship between the surface roughness Ra of a cathode drum, and the peeling stress of an electrolytic aluminum foil. It is the surface observation photograph (Ra = 0.33 micrometer) of the cathode drum after an etching. It is the surface observation photograph (Ra = 0.33 micrometer) of the back surface of an electrolytic aluminum foil. It is the surface observation photograph (Ra = 0.36 micrometer) of the surface of an electrolytic aluminum foil. It is a figure which shows the relationship between etching time and surface roughness Ra of a cathode drum. It is a figure which shows the relationship between the current density and the surface roughness Ra of the electrolytic aluminum foil. It is a figure which shows the relationship between the thickness of electrolytic aluminum foil, and surface roughness Ra. It is a cross-sectional photograph of the electrolytic aluminum foil of this invention. FIG. 10 is a partial schematic diagram of FIG. 9. It is the schematic which shows an example of the electrolytic aluminum foil manufacturing apparatus used with the manufacturing method of this invention. It is a schematic diagram of the cross section of the electrolytic aluminum foil manufacturing apparatus of FIG. It is an example of the application product (electric storage device) of electrolytic aluminum foil. It is a cross-sectional schematic diagram of the electrical storage device of FIG.

The present inventors have conducted intensive studies in view of the above points.
As a result, the electrolytic aluminum foil tends to increase the roughness of the substrate peeling surface (hereinafter simply referred to as the back surface) when a substrate (cathode drum) with increased surface roughness is used. It has been found that it is difficult to make it larger than 0.6 μm.
On the other hand, the deposition surface that is not in contact with the cathode drum (hereinafter simply referred to as the surface) always has a certain degree of roughness Ra when the electrolytic membrane is formed. Therefore, in order to obtain an electrolytic aluminum foil having the same degree of roughness Ra on both sides by the same simple manufacturing process as before, the electrolytic aluminum foil has a surface roughness Ra as small as possible according to the roughness Ra of the back surface. It was found that it should be manufactured as follows.

The electrolytic aluminum foil of the present invention obtained in consideration of the above points has a surface roughness Ra of 0.1 μm or more and 0.6 μm or less.
Specifically, as will be described later, the roughness Ra of the front surface and the back surface can be controlled in units of 0.1 μm, so that an electrolytic aluminum foil having a difference in roughness Ra of both surfaces of 0.2 μm or less can be obtained. it can.
By using said electrolytic aluminum for an electrical storage device, the discharge / charge efficiency of the electrical storage device can be stabilized.

Next, the manufacturing method of the electrolytic aluminum foil of this invention is demonstrated.
The method for producing an electrolytic aluminum foil of the present invention is obtained by applying an electric current between a cathode drum partially immersed in a plating solution for forming a foil and an anode plate, forming an aluminum electrolytic film on the cathode drum, and then peeling off. In the method for producing an electrolytic aluminum foil, the surface roughness Ra of the cathode drum is 0.1 μm or more and 0.6 μm or less, and the current applied when forming the aluminum electrolytic film is 0.25 A / dm ^2. The conditions are 20 A / dm ² or less and the roughness Ra of both surfaces is in the range of 0.1 μm to 0.6 μm.

  The surface roughness Ra of the cathode drum is 0.1 μm or more and 0.6 μm or less. If it is less than 0.1 μm, the roughness of the back surface will be smaller than the minimum roughness (0.1 μm) of the surface, so that it will not be possible to make it the same level as the surface roughness. On the other hand, the surface roughness Ra of the cathode drum is 0.6 μm or less. When the surface roughness Ra of the cathode drum exceeds 0.6 μm, as shown in FIG. 2, the deposited electrolytic aluminum electrolytic membrane is brought into close contact with the cathode drum due to the anchor effect, and the peeling stress described later exceeds 10 MPa. It becomes difficult to peel from the drum.

The current density is 0.25 A / dm ² or more and 20 A / dm ² or less. When it is less than 0.25 A / dm ^2, the deposition efficiency of the plating film is lowered and it is difficult to continuously produce the plating film. On the other hand, if it exceeds 20 A / dm ² , the surface roughness Ra exceeds 0.6 μm and becomes rough. As shown in FIG. 1, the roughness Ra of the back surface does not exceed 0.6 μm even if the surface roughness of the cathode drum is roughened. If the surface roughness Ra exceeds 0.6 μm, the roughness of the back surface Can not be as much as. Details will be described later in Examples. In addition, if it exceeds 20 A / dm ² , stable plating treatment becomes difficult due to decomposition of nitrogen-containing compounds, etc., or the film becomes dark due to a side reaction product generated due to insufficient complex ions of aluminum or excessive electrons due to excessive electrons. It is easy to come out.
In terms of film formation efficiency, the current density is preferably 1 A / dm ² or more, more preferably 3 A / dm ² or more. When the surface roughness Ra is suppressed to 0.55 μm or less, it is preferably 15 A / dm ² or less, and when it is suppressed to 0.50 μm or less, 10 A / dm ² or less is preferable.

  The thickness of the electrolytic aluminum foil is not particularly limited, but is preferably 5 μm or more. When the thickness is less than 5 μm, the aluminum electrolytic membrane is easily broken when it is peeled off from the cathode drum, which may cause a problem when a long electrolytic aluminum foil is produced. The upper limit is not particularly limited, but is preferably 20 μm or less. When used for an electricity storage device, it is superior to a rolled foil in the effect of improving the high energy density of the electricity storage device by reducing the thickness.

Below, the further preferable point in this invention is described.
The electrolytic aluminum foil can be obtained by electrodeposition from a plating solution for forming a foil containing at least (1) a dialkyl sulfone, (2) an aluminum halide, and (3) a nitrogen-containing compound. An aluminum foil having a thickness of 5 μm or more and 20 μm or less, which is very difficult to manufacture by a rolling method, can be easily manufactured by an electrolytic method. As the foil forming plating solution, for example, the following can be used. The thickness can be 15 μm or less.

  Dialkyl sulfone to be included in the plating solution for forming foil is one having 1 to 6 carbon atoms in the alkyl group such as dimethyl sulfone, diethyl sulfone, dipropyl sulfone, dihexyl sulfone, methyl ethyl sulfone (both linear and branched). Dimethylsulfone can be preferably employed from the viewpoint of good electrical conductivity and availability.

  Examples of the aluminum halide include aluminum chloride and aluminum bromide, but from the viewpoint of minimizing the amount of moisture contained in the plating solution which is a factor that hinders the precipitation of aluminum. The halide is preferably anhydrous.

  The aluminum halide is desirably 1.5 to 6.0 mol and more desirably 2.0 to 4.0 mol with respect to 10 mol of the dialkyl sulfone. If the blending amount of the aluminum halide is less than 1.5 mol with respect to 10 mol of the dialkyl sulfone, the formed aluminum film may be darkened or the film forming efficiency may be lowered. On the other hand, if it exceeds 6.0 mol, the liquid resistance of the plating solution increases, and the plating solution may generate heat and decompose.

  The amount of the nitrogen-containing compound added can be, for example, 0.001 to 2.0 mol with respect to 10 mol of dialkyl sulfone. If the dialkyl sulfone is less than 0.001 mol, darkening is likely to occur in the foil. On the other hand, if it exceeds 2.0 mol, the amount of moisture in the plating solution for foil formation increases, and it becomes difficult to deposit the aluminum foil. As for the addition amount of a nitrogen-containing compound, it is more preferable to add 0.005-0.2 mol with respect to 10 mol of dialkyl sulfones.

Nitrogen-containing compounds include ammonium halide, hydrogen halide salt of primary amine, hydrogen halide salt of secondary amine, hydrogen halide salt of tertiary amine, general formula: R ¹ R ² R ³ R ⁴ N · X A quaternary ammonium salt represented by (R ^{1 to} R ⁴ are the same or different alkyl groups, X represents a counter anion for a quaternary ammonium cation), and at least one selected from the group consisting of nitrogen-containing aromatic compounds Can be used. These nitrogen-containing compounds may be used alone or in combination of two or more.

Examples of the ammonium halide that can be employed as the nitrogen-containing compound include ammonium chloride and ammonium bromide. In addition, as primary amine to tertiary amine, the carbon number of alkyl groups such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, hexylamine, methylethylamine, etc. 1 to 6 (which may be linear or branched) can be exemplified. Examples of the hydrogen halide include hydrogen chloride and hydrogen bromide. R ¹ in a quaternary ammonium salt represented by the general formula: R ¹ R ² R ³ R ⁴ N · X (R ^{1 to} R ⁴ are the same or different alkyl groups, X represents a counter anion for a quaternary ammonium cation) Examples of the alkyl group represented by ˜R ⁴ include those having 1 to 6 carbon atoms (which may be linear or branched) such as a methyl group, an ethyl group, a propyl group, and a hexyl group. Examples of X include halide ions such as BF ₄ ⁻ and PF ₆ ^{− in} addition to halogen ions such as chlorine ion, bromine ion and iodine ion. Specific examples of the compound include tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, and tetraethylammonium tetrafluoride. Examples of nitrogen-containing aromatic compounds include phenanthroline. Suitable nitrogen-containing compounds include hydrochlorides of tertiary amines such as trimethylamine hydrochloride in terms of facilitating the production of high-purity aluminum foil having a high ductility at a high film formation rate.

  The temperature of the foil forming plating solution can be set to 60 to 150 ° C. When the temperature is less than 60 ° C., the amount of carbon increases and the tensile strength tends to decrease. In addition, darkening tends to occur due to insufficient supply of ions. On the other hand, when the temperature exceeds 150 ° C., the structure of the complex formed by the aluminum halide and the alkyl sulfone changes with time, and it tends to be difficult to obtain a uniform foil continuously. The temperature of the plating solution for forming foil is more preferably 80 ° C. or higher and 120 ° C. or lower, and further preferably 90 ° C. or higher and 115 ° C. or lower.

The foil forming plating solution is prepared by heating a mixture of these components to the melting point of dialkyl sulfone in an atmosphere of nitrogen gas or inert gas, and dissolving the aluminum halide and the nitrogen-containing compound in the molten dialkyl sulfone. It is desirable to do in.
The electroplating treatment environment is preferably a dry atmosphere from the viewpoint of preventing the foil forming plating solution from deteriorating and extending its life.

By using the plating solution for forming the foil, an aluminum electrolytic foil having an aluminum content of more than 98.0 mass% can be obtained. When the aluminum content increases, the volume resistance decreases, so that the storage efficiency can be reduced when used for an energy storage device or the like. Moreover, since heat dissipation improves as volume resistance becomes small, when applying to the site | part where heat dissipation is calculated | required, it is suitable. The aluminum content is more preferably 99.0 mass% or more.
Moreover, when it exceeds 98.0 mass%, when manufacturing an aluminum foil by an electrolysis method, it can suppress that the aluminum film formed on a cathode becomes hard and ductility becomes small, and when peeling an aluminum foil from a cathode It is easy to avoid the problem of cracking.

  Examples of the base material (cathode drum) for forming the aluminum foil include a stainless plate, a titanium plate, an aluminum plate, a nickel plate, and a copper plate. In addition, as a material of an anode plate, aluminum can be illustrated, for example.

In the present invention, the roughness of the front and back surfaces of the electrolytic aluminum foil is measured using an ultra-deep shape measuring microscope (KEYENCE: VK-8500), and the foil is attached to a smooth plate using a double-sided tape. The swell component of the foil was not included, and the arithmetic average roughness Ra was calculated from the roughness curve. The arithmetic average roughness Ra was calculated according to JIS B0601 '2001.
Further, the surface roughness of the cathode drum was similarly calculated by the arithmetic average roughness Ra.
Hereinafter, the term “roughness” refers to the arithmetic average roughness Ra.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is limited to the following description and is not interpreted.
Example 1
FIG. 11 is a view showing the electrolytic aluminum foil manufacturing apparatus used in this embodiment, and FIG. 12 is a schematic view of the cross section of FIG. Electrolytic aluminum foil manufacturing apparatus 1 (hereinafter may be abbreviated as apparatus 1) includes a lid 1a, an electrolytic cell 1b, a cathode drum 1c, an anode plate 1d, a foil outlet 1f, and a gas supply for introducing a heated inert gas G. A mouth 1g, a ceiling 1k, and a DC power source (not shown) are provided. A guide roll 1e, a heater power source 1h, a heater 1i, an electrolyte circulation device 1j, a stirring flow guide 1m, and a stirring blade 1n are provided.
A plating solution L for forming a foil is placed in the electrolytic cell 1b. Also, the water volatilized from the foil forming plating solution L adheres to the lid 1a to form droplets, and if this droplet falls into the foil forming plating solution L, the composition of the solution may change and a uniform foil may not be formed. Therefore, the heated inert gas G is supplied into the lid portion 1a.

The operation of the apparatus 1 will be described below.
First, an electric current is applied between the cathode drum 1c and the anode plate 1d partially immersed in the foil forming plating solution. At this time, the aluminum electrolytic membrane F is deposited on the cathode drum 1c while rotating the cathode drum 1c. During energization, the electrolytic solution L is stirred by the rotation of the stirring blade 1n, and the flow of the electrolytic solution L is generated between the cathode drum 1c and the anode plate 1d by the stirring flow guide 1m. An aluminum electrolytic film is formed on the surface of the cathode drum 1c immersed in the electrolytic solution L.
When the cathode drum 1c is rotated, the formed aluminum electrolytic membrane is exposed on the liquid surface, and the aluminum electrolytic membrane is formed on the surface of the newly immersed cathode drum 1c. Can be formed.

Thereafter, the aluminum electrolytic membrane is peeled off. The aluminum electrolytic membrane rising on the liquid surface is peeled off from the surface of the cathode drum 1c. Thereby, the electrolytic aluminum foil F can be obtained.
The end portion of the peeled electrolytic aluminum foil F is guided to the peeling guide roll 1e, and an openable / closable foil drawer opening 1f formed in the gap between the lid portion 1a formed on the side surface of the apparatus 1 and the electrolytic cell 1b is opened. , Continuously pulled out in the direction of the outside of the device 1.

  The plating solution L for forming foil was constructed with dimethylsulfone, anhydrous aluminum chloride, and trimethylamine hydrochloride so that the molar ratio was 10: 3.8: 0.05. The anode plate was an Al plate with a purity of 99%. The cathode drum was made of Ti.

After depositing an aluminum electrolytic film on the cathode drum under the above conditions, the aluminum electrolytic film was peeled off to obtain an electrolytic aluminum foil.
The plating conditions were an electrolytic solution L treatment temperature of 110 ° C. and a current density of 5 A / dm ² . The rotation speed of the cathode drum was adjusted so that the time of immersion in the electrolytic solution L was 25 minutes. The obtained electrolytic aluminum foil had a width of 200 mm and a length of 400 mm.

First, it was studied to control the roughness of the back surface of the electrolytic aluminum foil.
The surface of the cathode drum was roughened with an etching solution. The surface roughness of the cathode drum was changed by using World Metal Co., Ltd. (trade name T-22) as an etchant, with etching times of 0 minutes, 10 minutes, 12 minutes, 15 minutes, 17 minutes, and 20 minutes. The relationship between the etching time and the surface roughness of the cathode drum is shown in FIG. Note that two types of etching solutions having temperatures of 80 ° C. and 90 ° C. were used.
An electrolytic aluminum foil was manufactured by using the above-described electrolytic aluminum foil manufacturing apparatus shown in FIGS.
In FIG. 1, the horizontal axis indicates the surface roughness of the cathode drum, and the vertical axis indicates the roughness of the back surface of the electrolytic aluminum foil.
FIG. 3 is an observation photograph of the peripheral surface (surface roughness 0.33 μm) of the cathode drum. FIG. 4 is an observation photograph of the back surface (roughness 0.33 μm) of the electrolytic aluminum foil. When the surface roughness of the cathode drum is in the range of 0.35 μm or less, the back surface of the electrolytic aluminum foil has almost the same roughness because the surface property of the cathode drum is transferred almost as it is. However, even if the surface roughness of the cathode drum is rough, the roughness of the back surface of the electrolytic aluminum foil is not so rough. Even if the surface roughness of the cathode drum is rougher than 0.6 μm, the roughness of the back surface is The range is 0.6 μm or less.
Moreover, when the surface roughness of the cathode drum exceeded 0.6 μm, it was often broken when the aluminum electrolytic membrane was peeled off, and the electrolytic aluminum foil could not be obtained continuously.

Next, it was studied to control the surface roughness of the electrolytic aluminum foil. FIG. 7 is a diagram showing the results.
As the plating conditions, first, the current density was set to 2 A / dm ² , and the surface roughness of the electrolytic aluminum foil was measured.
The treatment temperature of the electrolytic solution L was 110 ° C. A cathode drum having an etching time of 0 minute (surface roughness of 0.08 μm) was used.
An aluminum electrolytic film was formed on the surface of the cathode drum until the thickness became 20 μm, and then the electrolytic aluminum foil was peeled off. The surface of the obtained electrolytic aluminum foil had a roughness of 0.36 μm.
Thereafter, was prepared in the same manner at a current density of ^{5A / dm 2, 10A / dm} 2, 15A / dm 2, 20A / dm 2, the roughness of the surface as it increases the current density 0.41 .mu.m, 0.5 [mu] m, 0 When the current density was increased to 25 A / dm ² , the roughness exceeded 0.6 μm to 0.64 μm.

  FIG. 5 is an observation photograph of the surface (roughness 0.36 μm). As described above, an electrolytic aluminum foil having almost the same roughness as the back surface and having the same roughness on both sides could be obtained from the manufacturing process almost the same as the conventional one.

  FIG. 9 is a cross-sectional photograph of an aluminum foil obtained by the electrolytic method of this embodiment. FIG. 10 is a schematic diagram thereof. In this aluminum foil, a large number of aluminum crystal grains a extending in the thickness direction of the foil were observed, and the structure was completely different from that of the rolled foil. In the figure, b is the surface of the foil. The ends of the crystal grains a are exposed on the surface, and the exposed ends of the crystal grains a are convex, so that the surface can be roughened. When the current density is increased, the crystal grain a becomes larger, so that it is presumed that the convexity at the end becomes similar and the roughness increases.

(Example 2)
The thickness of the obtained electrolytic aluminum foil was changed, and the change in the surface roughness due to this thickness was observed.
An electrolytic aluminum foil was produced in the same manner as in Example 1 except that the rotation speed of the cathode roll was adjusted with respect to Example 1.
FIG. 8 shows the result. The specific numerical values are shown in Table 1. When the thickness of the foil is in the range of 10 to 25 μm, the surface roughness tends to increase as the thickness increases. On the other hand, in the thickness range of 10 μm or less, the surface roughness is approximately constant at about 0.2 μm.

Considering from Examples 1 and 2, when producing electrolytic aluminum foil continuously using a production apparatus equipped with a cathode drum, in order to make the roughness of the front and back surfaces the same, the roughness of the surface is It is necessary to control the current density and foil thickness so that the maximum roughness of the back surface is 0.6 μm or less. On the other hand, the roughness of the back surface is 0.1 μm or more of the minimum roughness of the surface. It was confirmed that the surface roughness needs to be controlled.
In addition, it turned out from the result of FIG. 7 of Example 1 and Table 1 that the surface roughness can be sufficiently managed in units of 0.1 m depending on the current density and thickness. On the other hand, it was found from FIG. 1 and FIG. 6 that the roughness of the back surface can be sufficiently managed in units of 0.1 μm by the etching time of the cathode drum. Therefore, as shown in Example 1, the difference in surface roughness between the front surface and the back surface can be controlled to 0.2 μm or less, further 0.1 μm or less, and further 0.05 μm or less.

(Example 3)
An applied product of the electrolytic aluminum foil using the electrolytic aluminum foil of the present invention as a positive electrode current collector for an electricity storage device was produced.
The electrolytic aluminum foil obtained in Example 1 (surface roughness 0.36 μm, back surface roughness 0.33 μm) was used as a positive electrode current collector, and a positive electrode active material applied to the surface was used as a positive electrode. An electricity storage device shown in FIG. FIG. 14 is a cross section taken along the line AA in FIG. The power storage device 100 has a configuration in which an organic electrolytic solution containing a fluorine compound is filled in the housing 10 and the electrode unit 8 is immersed in the organic electrolytic solution. The electrode unit 8 has a structure in which a belt-like positive electrode 11, a negative electrode 12, and a separator 3 are laminated in the order of positive electrode-separator-negative electrode-separator to form a laminate, and this laminate is wound. The housing 10 is made of a metal material, and an insulating layer 4 is formed on the inside thereof. In addition, the casing 10 is formed with a positive terminal 5 and a negative terminal 6 that are connection terminals with an external device. The positive terminal 5 and the positive electrode of the electrode unit 8 are electrically connected to the negative terminal 6 and the negative electrode of the electrode unit 8, respectively. Connected. As shown in FIG. 14, since the positive electrode 11 and the negative electrode 12 are physically separated by the separator 3, they are not directly energized. However, the separator 3 is made of a porous material through which the organic electrolyte 7 can permeate, and the positive electrode 11 and the negative electrode 12 are electrically connected via the organic electrolyte 7.
The positive electrode 11 has an electrolytic aluminum foil as a positive electrode current collector, LiMn ₂ O ₄ is applied as a positive electrode active material on the surface thereof, and the negative electrode 12 has a copper foil as a negative electrode current collector, and graphite as a negative electrode active material on the surface thereof. It has been applied. The positive electrode which apply | coated the positive electrode active material to the back surface of the electrolytic aluminum foil of this invention, and the positive electrode which apply | coated the positive electrode active material to the surface were produced. The application of the active material on both the front and back surfaces was good in workability. Then, the charging efficiency and the discharging efficiency of the electricity storage device were compared, and the same performance was obtained in both cases.

  DESCRIPTION OF SYMBOLS 1: Electrolytic aluminum manufacturing apparatus, 1a: Lid part, 1b: Electrolysis tank, 1c: Cathode drum, 1d: Anode plate, 1e: Guide roll, 1f: Foil extraction port, 1g: Gas supply port, 1h: Heater power supply, 1i : Heater, 1j: Electrolyte circulation device, 1k: Ceiling, 1m: Stirring flow guide, 1n: Stirring blade, F: Electrolytic aluminum foil, G: Heated inert gas, L: Plating solution for forming foil, 3: Separator 4: insulating layer, 5: positive electrode terminal, 6: negative electrode terminal, 7: organic electrolyte, 8: electrode unit, 10: housing, 11: positive electrode, 12: negative electrode, 100: electricity storage device

Claims (3)

A base material peeling surface and a deposition surface obtained by peeling after forming an aluminum electrolytic film on the cathode drum by applying an electric current between the cathode drum partially immersed in the foil forming plating solution and the anode plate In the method for producing aluminum foil,
When forming the aluminum electrolytic membrane, the surface roughness Ra of the cathode drum is 0.1 μm or more and 0.6 μm or less, whereby the roughness Ra of the substrate peeling surface is 0.1 μm or more and 0.6 μm or less. And the applied current is 0.25 A / dm ² or more and 20 A / dm ² or less, and the aluminum electrolytic membrane is formed to a thickness of 5 μm or more and 25 μm or less, whereby the roughness Ra of the precipitation surface In the range of 0.1 μm or more and 0.6 μm or less, and the difference in roughness Ra between the substrate peeling surface and the precipitation surface is 0.2 μm or less. 2. The method for producing an aluminum foil according to claim 1 , wherein the foil forming plating solution contains at least (1) a dialkyl sulfone, (2) an aluminum halide, and (3) a nitrogen-containing compound. The nitrogen-containing compound includes ammonium halide, hydrogen halide salt of primary amine, hydrogen halide salt of secondary amine, hydrogen halide salt of tertiary amine, general formula: R ¹ R ² R ³ R ⁴ N · At least one selected from the group consisting of a quaternary ammonium salt represented by X (R ^{1 to} R ⁴ are the same or different alkyl groups, X represents a counter anion for a quaternary ammonium cation), and a nitrogen-containing aromatic compound The method for producing an aluminum foil according to claim 2 , wherein:

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