Carbon current collector for batteries

Abstract

To provide a carbon current collector for a battery with good electrical and mechanical properties.SOLUTION: A carbon current collector for a battery includes a sintered product of an inorganic binder, and a carbon powder uniformly dispersed in the sintered material of the inorganic binder, the carbon powder contains graphite powder, and at least two frequency peaks exist in the frequency distribution of the particle size of the graphite powder measured by a laser diffraction method, and a content of the graphite powder is 60 mass% or more with respect to the mass of the carbon current collector for the battery.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to carbon current collectors for batteries, and more particularly to rod-shaped carbon current collectors for cylindrical dry cell batteries. [Background technology]

[0002] Manganese dry cell batteries have long been widely used as power sources for electronic devices such as portable devices and information equipment. In manganese dry cell batteries, a cylindrical positive electrode mixture is housed in a bottomed cylindrical negative electrode container. A separator is placed between the positive electrode mixture and the negative electrode container. A carbon rod, which functions as a positive electrode current collector, is press-fitted into the center of the positive electrode mixture. The carbon rod is electrically connected to a positive electrode terminal plate that covers the opening of the battery container. Various types of such carbon rods have been disclosed.

[0003] Patent Document 1 discloses a carbon rod (carbon current collector for batteries) obtained by mixing carbonaceous powders such as graphite, carbon black, and coke with clay and firing the mixture. Patent Document 1 states that when the above carbon rod is used in a manganese dry cell, the permeability of the electrolyte can be suppressed.

[0004] Patent Document 2 discloses a carbon current collector for dry cell batteries comprising a sintered inorganic binder and carbon powder uniformly dispersed within the sintered inorganic binder. Patent Document 2 discloses that the carbon current collector for dry cell batteries is obtained by mixing carbon powder, an inorganic binder, an additive, and water, then reducing the pressure and degassing the mixture, compressing and molding it, and finally drying and firing it. Furthermore, Patent Document 2 states that the carbon powder content in the above mixture is more than half.

[0005] Furthermore, Patent Document 3 discloses a sliding material comprising a calcined inorganic binder and carbon powder uniformly dispersed in the calcined product. Patent Document 3 discloses a method for producing a carbon-based solid sliding material, which includes mixing carbon powder with an inorganic binder, shaping it into a desired form, and then calcining it in a non-oxidizing atmosphere. Patent Document 3 discloses that the inorganic binder content should be 50% by mass or more. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-97897 [Patent Document 2] Japanese Patent Publication No. 2012-204080 [Patent Document 3] Japanese Patent Publication No. 2008-207998 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the method described in Patent Document 1, cracks may occur during firing, resulting in the failure to obtain carbon rods (carbon current collectors for batteries), and the obtained carbon current collectors for batteries may not have sufficient strength to assemble the battery.

[0008] According to the invention described in Patent Document 2, a current collector rod for dry cell batteries (carbon current collector for batteries) has been obtained that has good electrical properties and also somewhat good mechanical properties. In this case, although cracking during firing has been reduced, it was still sometimes not possible to obtain sufficient strength to assemble the battery.

[0009] Therefore, the present invention provides a carbon current collector for batteries that possesses both excellent electrical and mechanical properties. [Means for solving the problem]

[0010] The inventors, after diligent research, discovered that the above problems could be solved by the following means, and thus completed the present invention. That is, the present invention is as follows: <Aspect 1> A carbon current collector for a battery comprising a sintered product of an inorganic binder and carbon powder uniformly dispersed in the sintered product of the inorganic binder, The carbon powder contains graphite powder, and In the frequency distribution of particle sizes of the graphite powder measured by laser diffraction, there are at least two frequency peaks, and A carbon current collector for a battery, wherein the content of the graphite powder is 60% by mass or more relative to the mass of the carbon current collector for the battery. <Aspect 2> The carbon current collector for a battery according to aspect 1, wherein in the frequency distribution of particle sizes of the graphite powder, the largest particle size among at least two particle sizes corresponding to the frequency peak is at least twice the smallest particle size. <Aspect 3> The carbon current collector for a battery according to aspect 1 or 2, wherein, in the frequency distribution of particle sizes of the graphite powder, the difference between the largest particle size and the smallest particle size among at least two particle sizes corresponding to the frequency peak is 10 μm or more. <Aspect 4> A carbon current collector for a battery according to any one of aspects 1 to 3, wherein in the frequency distribution of the particle size of the graphite powder, at least two particle sizes corresponding to the frequency peaks are all 150 μm or less. <Aspect 5> A carbon current collector for a battery according to any one of aspects 1 to 4, wherein the particle size corresponding to the frequency peak in the frequency distribution of the particle size of the inorganic binder measured by laser diffraction is smaller than the smallest particle size among at least two particle sizes corresponding to the frequency peak of the carbon powder. <Aspect 6> A carbon current collector for a battery according to any one of aspects 1 to 5, wherein the ratio of the mass of the carbon powder to the sintered inorganic binder is 1.5 to 6.0. <Aspect 7> The carbon current collector for a battery according to any one of aspects 1 to 6, wherein the sintered inorganic binder is a sintered inorganic binder selected from the group consisting of kaolinite, sericite, montmorillonite, and bentonite clays, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, and silicone rubber. <Aspect 8> A mixture is provided by mixing carbon powder and inorganic binder powder. To mold the mixture to provide a molded product of a desired shape, and The molded product is dried and fired. Includes, The carbon powder contains at least two types of graphite powders, for the at least two types of graphite powders, the particle diameters corresponding to the frequency peaks in the frequency distribution of the particle diameters measured by the laser diffraction method are different from each other, and the content of the graphite powder is 60% by mass or more based on the mass of the carbon current collector for a battery. A method for manufacturing a carbon current collector for a battery.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a carbon current collector for a battery having good electrical characteristics and mechanical characteristics.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is an explanatory diagram of a frequency peak and the corresponding particle diameter in the particle size distribution of the graphite powder in the present invention. [Figure 2] FIG. 2 is a diagram showing the particle size distribution of graphite A (D50: 38.8 μm) in an example. [Figure 3] FIG. 3 is a diagram showing the particle size distribution of graphite B (D50: 4.8 μm) in an example. [Figure 4] FIG. 4 is a diagram showing the particle size distribution (frequency) of a mixture of two types of graphite in equal amounts.

Embodiments for Carrying Out the Invention

[0013] 《Carbon Current Collector for a Battery》 The carbon current collector for a battery of the present invention is a carbon current collector for a battery including a sintered product of an inorganic binder and carbon powder uniformly dispersed in the sintered product of the inorganic binder, where the carbon powder contains graphite powder, and in the frequency distribution of the particle diameters of the graphite powder measured by the laser diffraction method, at least two frequency peaks exist, and the content of the graphite powder is 60% by mass or more based on the mass of the carbon current collector for a battery.

[0014] Conventionally, it has been known that electrical properties can be improved by increasing the content of carbonaceous particles, as described in Patent Document 2, and that mechanical properties can be improved by increasing the content of inorganic binders, as described in Patent Document 3. However, it has been difficult to improve both electrical and mechanical properties simultaneously.

[0015] In response to this, the inventors conducted diligent research and, surprisingly, discovered that by uniformly mixing graphite particles of multiple different particle sizes, it is possible to improve mechanical properties without impairing electrical properties. In particular, the carbon current collector for batteries of the present invention can have sufficient compressive strength to suppress cracking when covering the positive electrode terminal plate during battery assembly.

[0016] Although we do not wish to be bound by theory, it is thought that this effect is due to the fact that smaller graphite particles fill the cavities between larger graphite particles, resulting in a dense arrangement of graphite, and that the spaces between them are further filled with an inorganic binder, thereby achieving high mechanical strength even with a small amount of inorganic binder, and that the carbon current collector for batteries as a whole has high conductivity and flexibility due to the large amount of graphite particles that have high conductivity and flexibility.

[0017] In this invention, "frequency distribution" refers to a graph obtained by plotting data obtained by laser diffraction, with the horizontal axis representing the logarithm of particle size and the vertical axis representing frequency.

[0018] In the frequency distribution shown in Figure 1, the maximum frequency values ​​A1 and A2 are referred to as "frequency peaks," and the particle sizes B1 and B2 that take place at these frequency peaks are referred to as "particle sizes corresponding to frequency peaks."

[0019] With respect to the particle sizes described herein, "Dx" (where x is a number greater than 0 and less than 100) indicates the particle size at which the cumulative frequency reaches x% when the particle size distribution is obtained by laser diffraction. For example, D10 and D50 indicate particle sizes at which the cumulative frequency reaches 10% and 50%, respectively. In particular, D50 is sometimes referred to as the median diameter.

[0020] The following describes each component of the present invention.

[0021] <Sintered products of inorganic binders> In the present invention, the sintered inorganic binder is obtained by firing the inorganic binder together with carbon powder at a temperature below the melting point of the inorganic binder, thereby sintering the inorganic binder.

[0022] As such inorganic binders, at least one inorganic binder selected from the group consisting of kaolinite, sericite, montmorillonite, and bentonite clays, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, and silicone rubber can be used.

[0023] From the viewpoint of improving the mechanical properties of a carbon current collector for batteries, it is preferable that the particle size corresponding to the frequency peak in the frequency distribution of inorganic binder particle sizes measured by laser diffraction is smaller than the smallest of the at least two particle sizes corresponding to the frequency peak of carbon powder.

[0024] For example, if the smallest particle size among at least two particle sizes corresponding to the frequency peak of the carbon powder is 6 μm, then the particle size corresponding to the frequency peak in the frequency distribution of the inorganic binder particle size measured by laser diffraction may be 1 μm or more, 2 μm or more, or 3 μm or more, and may also be less than 6 μm, 5 μm or less, or 4 μm or less.

[0025] <Carbon powder> Carbon powder is carbon powder uniformly dispersed in a sintered inorganic binder. This carbon powder contains graphite powder.

[0026] Furthermore, the carbon powder may contain other carbon powders besides graphite powder.

[0027] From the viewpoint of improving the electrical properties of the resulting carbon current collector for batteries, it is preferable that the carbon powder content be 60% or more by mass, 65% or more by mass, 67% or more by mass, or 70% or more by mass, relative to the mass of the carbon current collector for batteries. From the viewpoint of improving the mechanical properties of the resulting carbon current collector for batteries, it is preferable that the content be 85% or less by mass, 83% or less by mass, 80% or less by mass, 77% or less by mass, or 75% or less by mass.

[0028] From the viewpoint of improving the electrical properties of the resulting carbon current collector for batteries, the ratio of the mass of carbon powder to the mass of the sintered inorganic binder in a carbon current collector for batteries is preferably 1.5 or more, 1.7 or more, 2.0 or more, 2.3 or more, 2.5 or more, 3.0 or more, or 3.5 or more. From the viewpoint of improving the mechanical properties of the resulting carbon current collector for batteries, this ratio is preferably 6.0 or less, 5.5 or less, 5.0 or less, 4.7, 4.5 or less, or 4.0 or less.

[0029] (Graphite powder) For example, artificial graphite or natural graphite can be used as graphite powder.

[0030] The graphite powder content is 60% by mass or more relative to the mass of the carbon current collector for batteries. From the viewpoint of improving the mechanical strength of the resulting carbon current collector for batteries, a content of 65% by mass or more, 67% by mass or more, or 70% by mass or more is preferable. This content may be 85% by mass or less, 80% by mass or less, 77% by mass or less, or 75% by mass or less.

[0031] In the frequency distribution of graphite powder particle sizes measured by laser diffraction, at least two frequency peaks are present.

[0032] For example, the above state of frequency peaks can be obtained by using at least two types of graphite powders with different average particle sizes, such as at least two types of graphite powders with different D50 values ​​as measured by the cumulative distribution of laser diffraction.

[0033] In the frequency distribution of particle sizes of graphite powder, it is preferable from the viewpoint of improving the mechanical properties of the graphite powder that, among at least two particle sizes corresponding to frequency peaks, the largest particle size is 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, or 10 times larger than the smallest particle size. The largest particle size may be 20 times or less, or 15 times or less, than the smallest particle size.

[0034] In the frequency distribution of particle sizes of graphite powder, it is preferable from the viewpoint of improving the mechanical properties of graphite powder that the difference between the largest particle size and the smallest particle size among at least two particle sizes corresponding to frequency peaks is 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, 55 μm or more, or 60 μm or more. The above difference may be 100 μm or less, 90 μm or less, 80 μm or less, 75 μm or less, 70 μm or less, or 65 μm or less.

[0035] In the frequency distribution of particle sizes of graphite powder, it is preferable from the viewpoint of improving the mechanical properties of the graphite powder that at least two particle sizes corresponding to frequency peaks are all 150 μm or less, 130 μm or less, 110 μm or less, 100 μm or less, 90 μm or less, 80 μm or less, or 70 μm or less.

[0036] While the particle size corresponding to the frequency peak does not necessarily correspond to the D50 of the graphite powder, a positive correlation exists between the two. The above relationship regarding the particle size corresponding to the frequency peak can be obtained by setting the difference in D50 of the graphite powder to 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, or 30 μm or more, and 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less.

[0037] D50, which has the largest average particle size among the graphite powders, may be, for example, 20 μm or more, 23 μm or more, 25 μm or more, 28 μm or more, 30 μm or more, 33 μm or more, 35 μm or more, or 38 μm or more, and may also be 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 42 μm or less, or 40 μm or less.

[0038] Furthermore, D50, which has the smallest average particle size among the graphite powders, may be 1 μm or more, 2 μm or more, 3 μm or more, or 4 μm or more, and may also be 20 μm or less, 18 μm or less, 15 μm or less, 13 μm or less, 10 μm or less, 8 μm or less, 6 μm or less, or 5 μm or less.

[0039] (Other carbon powders) Other carbon powders that can be used include, for example, spherical carbon powders such as carbon black, and linear carbon powders such as carbon nanotubes, milled fibers, and chopped fibers.

[0040] The D50 of other carbon powders may be, for example, 1 μm or less, 900 nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, 600 nm or less, 550 nm or less, 500 nm or less, 450 nm or less, 400 nm or less, 350 nm or less, or 300 nm or less, and may also be 10 nm or more, 30 nm or more, 50 nm or more, 70 nm or more, 100 nm or more, 120 nm or more, 150 nm or more, 180 nm or more, or 200 nm or more.

[0041] Method for manufacturing carbon current collectors for batteries The present invention's method for manufacturing carbon current collectors for batteries is: To provide a mixture by mixing carbon powder and inorganic binder powder. To mold the mixture to provide a molded product of a desired shape, and The molded product is dried and fired. A method for manufacturing a carbon current collector for batteries, including, The carbon powder comprises at least two types of graphite powder, The particle sizes corresponding to the frequency peaks in the frequency distribution of the particle sizes measured by laser diffraction for the at least two types of graphite powders are different from each other, and The content of the graphite powder is 60% by mass or more relative to the mass of the carbon current collector for the battery.

[0042] <Provision of mixture> The mixture is provided by mixing carbon powder and inorganic binder powder. For the carbon powder and inorganic binder, refer to the description of carbon current collectors for batteries.

[0043] Depending on the type of inorganic binder used, water may be further added to the mixture.

[0044] Furthermore, optional additives may be added to the mixture. Examples of additives include surfactants such as the sodium salt of β-naphthalene sulfonic acid formalin condensate, and thickeners such as gum arabic.

[0045] The means of mixing are not particularly limited and may be known mixing means such as a kneader or disper.

[0046] Of at least two types of graphite powders, the mass of the graphite powder with the smallest particle size corresponding to the frequency peak is m Cmin The mass of the graphite powder with the largest particle size corresponding to the frequency peak is m CMAX When this is the case, the mass ratio m Cmin / mCMAX It is desirable, from the perspective of generating multiple frequency peaks in the frequency distribution, that the value is 0.2 or higher, 0.3 or higher, 0.5 or higher, 0.7 or higher, or 0.9 or higher, and also 5.0 or lower, 4.0 or lower, 3.0 or lower, 2.0 or lower, 1.5 or lower, 1.2 or lower, or 1.1 or lower.

[0047] <Provision of molded products> The molded product is provided by molding a mixture.

[0048] The molding method is not particularly limited and may be a known extrusion molding machine such as a T-die.

[0049] <Drying and firing of molded products> The drying and firing of the molded product can be carried out using known means.

[0050] The firing temperature is not particularly limited as long as it is a temperature at which the inorganic binder can be sintered, for example, 600°C or higher, 650°C or higher, 700°C or higher, 750°C or higher, or 800°C or higher, 850°C or higher, or 900°C or higher, and may be 1200°C or lower, 1150°C or lower, 1100°C or lower, 1050°C or lower, or 1000°C or lower. [Examples]

[0051] The present invention will be specifically described by examples and comparative examples, but the present invention is not limited thereto.

[0052] Fabrication of carbon current collectors for batteries <Example 1> The following materials were mixed in the following parts by mass using an open kneader for 60 minutes, and the moisture content was adjusted to 20.0% by mass while heating to prepare the mixture. Inorganic binder: bentonite clay, 30 parts by mass Carbon powder: Graphite A (GREEN LIMITED COMPANY, GRAPHITE C92, D50: 38.8 μm), 17.5 parts by mass Carbon powder: Graphite B (Kowa Co., Ltd., LG-92, D50: 4.8 μm), 52.5 parts by mass Surfactant: Sodium salt of β-naphthalene sulfonic acid formalin condensate, 2 parts by mass Thickener: Gum arabic powder, 4 parts by mass Water: 30 parts by mass

[0053] Next, the moisture-adjusted mixture was extruded using an extrusion molding machine so that its cross-section was circular. Then, the extruded mixture was cut to the desired length, and then dried in a dryer at 150°C to evaporate the moisture, obtaining a cylindrical molded body with a diameter of 3 mm and a length of 180 mm.

[0054] The resulting molded body was fired at a temperature of 1150°C in a non-oxidizing atmosphere and then slowly cooled to obtain the carbon current collector for batteries of Example 1. Note that after firing, the mass of the bentonite-based clay was reduced to 95% of its pre-fired mass.

[0055] <Examples 2-4 and Comparative Examples 1-6> Except for changing the amount of each component added as shown in Table 1, carbon current collectors for batteries of Examples 2-4 and Comparative Examples 1-6 were obtained in the same manner as in Example 1. In Table 1, "Graphite C" refers to AGP-40 (D50: 131 μm) from Kobayashi Shoji Co., Ltd.

[0056] Furthermore, the firing process described above reduces the mass of the kaolinite clay to 88% of its original mass.

[0057] Measurement of frequency peaks The particle size distribution of graphite A and B used was measured by laser diffraction using a particle size distribution analyzer (MT3000, Microtrac-Bel). The particle size distributions of graphite A and B are shown in Figures 2 and 3, respectively.

[0058] By summing and normalizing the data from the obtained particle size distributions, the frequency distribution of the graphite mixtures obtained by mixing equal amounts of graphite A and B, as used in Examples 3 and 4, was obtained. This is shown in Figure 4. The particle sizes corresponding to the frequency peaks of graphite A and B were 6.00 μm and 67.86 μm, respectively.

[0059] Figure 4 shows that two frequency peaks are present in Example 3. The particle sizes corresponding to these frequency peaks were 6.54 μm and 67.86 μm. Although not shown in the figures, it can be inferred that at least two frequency peaks are also present in Examples 1 and 2.

[0060] Although not shown in the figures, the particle size distribution was also measured for bentonite-based clay and kaolinite-based clay in the same manner. The particle sizes corresponding to the frequency peaks of bentonite-based clay and kaolinite-based clay were 3.27 μm and 3.57 μm, respectively.

[0061] "evaluation" <Bending strength> The bending strength of the obtained carbon current collector for batteries was measured in accordance with JIS K 7074. Specifically, a load (three-point bending) was applied to one point of a test specimen simply supported at both ends, and the bending strength σb (MPa) was calculated using the fracture load or maximum load obtained by deflecting the test specimen at a predetermined test speed, using the following formula. σ b =(3P b L) / (2bh 2 ) In the formula, L represents the distance between supports (mm), b represents the width of the test specimen (mm), h represents the thickness of the test specimen (mm), and Pb represents the load at failure or maximum load (N).

[0062] <Axial compressive strength> The axial compressive strength of the obtained carbon current collectors for batteries was measured in accordance with JIS R 1608. Specifically, a load was applied to a test specimen fixed in the axial direction using a pressure plate, and the specimen was compressed at a predetermined test speed. The maximum load until the specimen underwent compressive failure was measured.

[0063] <Resistivity> A pair of terminals of a voltmeter were attached at a predetermined position with a predetermined distance L apart from each other along the longitudinal direction of a carbon rod. The diameter D of the carbon rod was 3 mm and the distance L was 30 mm. A power source for supplying current to the carbon rod was prepared, and the pair of terminals were attached to both ends of the carbon rod. An ammeter for measuring the current value supplied from the power source was attached between the carbon rod and the power source. A current I (1.0 A) was passed through the carbon rod, and the voltage E at that time was measured.

[0064] Using the current value I, the voltage value E, the diameter D of the carbon rod, and the distance L between the pair of terminals of the voltmeter, the electrical resistance R was obtained from the following formula (1). R=(πD 2 / 4)×(E / LI)···(1)

[0065] The configurations and evaluation results of the examples and comparative examples are shown in Table 1. In Table 1, m Cmin means the mass of the graphite powder having the smallest particle diameter among the particle diameters corresponding to the frequency peak, and m CMAX means the mass of the graphite powder having the largest particle diameter among the particle diameters corresponding to the frequency peak.

[0066]

Table 1

[0067] It can be understood from Table 1 that the carbon current collectors of Examples 1 to 4 have both good electrical characteristics and mechanical characteristics. Among them, when the content of the carbon powder is 70% by mass, the compressive strength is good, and when the content of the carbon powder is 80% by mass, the resistivity is low.

[0068] On the other hand, the carbon current collectors of Comparative Examples 1 to 5 that do not contain two types of graphite powder did not have good mechanical characteristics. Also, the carbon current collector of Comparative Example 6 that contains two types of graphite powder but has a content of graphite powder of 55% by mass also did not have good mechanical characteristics.

Explanation of symbols

[0069] A1, A2 frequency peak Particle size corresponding to frequency peaks B1 and B2

Claims

1. A carbon current collector for a battery comprising a sintered inorganic binder and carbon powder uniformly dispersed in the sintered inorganic binder, The carbon powder contains graphite powder, and The sintered inorganic binder is a sintered inorganic binder selected from the group consisting of kaolinite, sericite, montmorillonite, and bentonite clays, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, and silicone rubber, and In the frequency distribution of particle sizes of the graphite powder measured by laser diffraction, there are at least two frequency peaks, and A carbon current collector for a battery, wherein the content of the graphite powder is 60% by mass or more and 85% by mass or less, relative to the mass of the carbon current collector for the battery.

2. The carbon current collector for a battery according to claim 1, wherein, in the frequency distribution of particle sizes of the graphite powder, the largest particle size among at least two particle sizes corresponding to the frequency peaks is at least twice the smallest particle size.

3. The carbon current collector for a battery according to claim 1 or 2, wherein, in the frequency distribution of particle sizes of the graphite powder, the difference between the largest particle size and the smallest particle size among at least two particle sizes corresponding to the frequency peaks is 10 μm or more.

4. The carbon current collector for a battery according to any one of claims 1 to 3, wherein in the frequency distribution of particle sizes of the graphite powder, at least two particle sizes corresponding to the frequency peaks are all 150 μm or less.

5. A carbon current collector for a battery according to any one of claims 1 to 4, wherein the particle size corresponding to the frequency peak in the frequency distribution of particle sizes of the inorganic binder measured by laser diffraction is smaller than the smallest particle size among at least two particle sizes corresponding to the frequency peak of the carbon powder.

6. A carbon current collector for a battery according to any one of claims 1 to 5, wherein the ratio of the mass of the carbon powder to the sintered inorganic binder is 1.5 to 6.

0.

7. To provide a mixture by mixing carbon powder and inorganic binder powder. To mold the mixture to provide a molded product of a desired shape, and The molded product is dried and fired. A method for manufacturing a carbon current collector for batteries, including, The carbon powder comprises at least two types of graphite powder, The inorganic binder powder is a powder of at least one inorganic binder selected from the group consisting of kaolinite-type, sericite-type, montmorillonite-type, and bentonite-type clays, zeolite, diatomaceous earth, activated clay, silica, aluminum phosphate, silicone resin, and silicone rubber, and The particle sizes corresponding to the frequency peaks in the frequency distribution of the particle sizes measured by laser diffraction for the at least two types of graphite powders are different from each other, and The content of the graphite powder is 60% by mass or more and 85% by mass or less, relative to the mass of the carbon current collector for the battery. A method for manufacturing carbon current collectors for batteries.

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