WO2021019958A1

WO2021019958A1 - Resin member, active material retaining member, electrode, lead storage battery, and electric car

Info

Publication number: WO2021019958A1
Application number: PCT/JP2020/024410
Authority: WO
Inventors: 啓太鈴木
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2019-07-26
Filing date: 2020-06-22
Publication date: 2021-02-04
Also published as: WO2021019628A1; JPWO2021019958A1

Abstract

A lead storage battery 100 comprises a positive electrode 10 and a negative electrode 20, wherein the positive electrode 10 includes a tube 10a for retaining an active material, the tube 10a includes a resin member, the resin member includes a base material comprising polyester and a resin retained on the base material, the resin comprises an epoxy resin and an acrylic resin, and the content of the epoxy resin is over 0 mass% to 70 mass% or less based on the total amount of the epoxy resin and the acrylic resin.

Description

Resin members, active material holding members, electrodes, lead-acid batteries and electric vehicles

The present invention relates to a resin member, an active material holding member, an electrode, a lead storage battery, and an electric vehicle.

Lead-acid batteries are widely used as secondary batteries for industrial or consumer use, and in particular, lead-acid batteries for electric vehicles (for example, lead-acid batteries for automobiles, so-called batteries), UPS (Uninterruptable Power Supply), and disaster prevention (emergency). ) There is a great demand for lead-acid batteries for backup such as wireless power supplies and telephone power supplies.

In lead-acid batteries, an active material holding member capable of holding (accommodating) an active material may be used. For example, a lead-acid battery contains an active material holding member, a core metal (current collector) inserted in the active material holding member, and an electrode material (active material) filled between the active material holding member and the core metal. It is provided with an electrode having an electrode material (see, for example, Patent Document 1 below).

Japanese Unexamined Patent Publication No. 8-203506

By the way, the electrolytic solution in lead-acid batteries tends to contain sulfuric acid. Therefore, when an electrode having an active material holding member is used, the active material holding member comes into contact with sulfuric acid. However, conventionally, when the active material holding member contains a resin material, the mechanical strength (for example, tensile strength) of the active material holding member may decrease when the active material holding member comes into contact with sulfuric acid. When the mechanical strength of the active material holding member decreases, the active material holding member tends to deteriorate with the charge / discharge cycle, so that the active material leaks from the active material holding member and the battery life tends to decrease. Therefore, it is required that the resin member for obtaining the active material holding member suppresses the decrease in mechanical strength when it is brought into contact with sulfuric acid.

One aspect of the present invention is to provide a resin member capable of suppressing a decrease in mechanical strength when brought into contact with sulfuric acid. Another aspect of the present invention is to provide an active material holding member using the resin member. Another aspect of the present invention is to provide an electrode having the active material holding member, a lead storage battery provided with the electrode, and an electric vehicle provided with the lead storage battery.

One aspect of the present invention is a resin member used for an active material holding member, which comprises a base material containing polyester and a resin held on the base material, and the resin comprises an epoxy resin and an acrylic resin. Provided is a resin member containing, and the content of the epoxy resin is more than 0% by mass and 70% by mass or less based on the total amount of the epoxy resin and the acrylic resin.

According to such a resin member, it is possible to suppress a decrease in mechanical strength (for example, tensile strength) when the resin member is brought into contact with sulfuric acid. By obtaining the active material holding member using such a resin member, even if the active material holding member comes into contact with sulfuric acid in the lead storage battery, the decrease in the mechanical strength of the active material holding member is suppressed, and the charge / discharge cycle is accompanied. Sufficient battery life can be ensured by suppressing deterioration of the active material holding member.

Another aspect of the present invention provides an active material holding member including the above-mentioned resin member.

Another aspect of the present invention provides an electrode having the above-mentioned active material holding member and the active material held by the active material holding member.

Another aspect of the present invention provides a lead-acid battery comprising a positive electrode and a negative electrode, wherein at least one selected from the group consisting of the positive electrode and the negative electrode is the above-mentioned electrode.

Another aspect of the present invention provides an electric vehicle provided with the lead-acid battery described above.

According to one aspect of the present invention, it is possible to provide a resin member capable of suppressing a decrease in mechanical strength when brought into contact with sulfuric acid. According to another aspect of the present invention, it is possible to provide an active material holding member using the resin member. According to another aspect of the present invention, it is possible to provide an electrode having the active material holding member, a lead storage battery provided with the electrode, and an electric vehicle provided with the lead storage battery.

It is a schematic cross-sectional view which shows the lead storage battery which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the lead storage battery which concerns on one Embodiment of this invention.

Hereinafter, a mode for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

Since the specific gravity changes depending on the temperature, it is defined in this specification as the specific gravity converted at 20 ° C. In the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one step can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another step. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. “A or B” may include either A or B, or both. Unless otherwise specified, the materials exemplified in the present specification may be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. The term "process" is included in the term not only in an independent process but also in the case where the desired action of the process is achieved even if it cannot be clearly distinguished from other processes.

The resin member according to this embodiment is a resin member used for the active material holding member. The resin member according to the present embodiment includes a base material containing polyester and a resin held on the base material, the resin contains an epoxy resin and an acrylic resin, and the content of the epoxy resin is the epoxy. It is more than 0% by mass and 70% by mass or less based on the total amount of the resin and the acrylic resin. The resin member according to the present embodiment may be a sheet-shaped, tubular-shaped, or the like, and may be a resin sheet (sheet-shaped resin member).

The active material holding member according to the present embodiment includes a resin member according to the present embodiment. The active material holding member is a member for holding the active material of the battery. The "active material" includes both the post-chemical active material and the raw material of the pre-chemical active material. The active material holding member according to the present embodiment may include a tubular portion (for example, a cylindrical portion) including the resin member according to the present embodiment. The tubular portion can be formed by the resin member according to the present embodiment. The active material holding member can hold (accommodate) the active material inside the tubular portion. The active material holding member according to the present embodiment may include a plurality of tubular portions.

The electrode according to the present embodiment has an active material holding member according to the present embodiment and an active material held by the active material holding member. The lead-acid battery according to the present embodiment includes a positive electrode and a negative electrode, and at least one selected from the group consisting of the positive electrode and the negative electrode is the electrode according to the present embodiment. The lead-acid battery according to the present embodiment may include a separator arranged between the positive electrode and the negative electrode, and may not include the separator. The lead-acid battery according to the present embodiment may include an electrolytic solution. The electrolytic solution may contain sulfuric acid. The lead storage battery according to the present embodiment may be a liquid type lead storage battery, a control valve type lead storage battery, or the like, and may be a closed type lead storage battery, an open type lead storage battery, or the like.

According to this embodiment, it is possible to suppress a decrease in mechanical strength (for example, tensile strength) when the resin member is brought into contact with sulfuric acid. Therefore, by obtaining the active material holding member using such a resin member, even if the active material holding member comes into contact with sulfuric acid in the lead storage battery, the decrease in the mechanical strength of the active material holding member is suppressed, and the charge / discharge cycle As a result, deterioration of the active material holding member is suppressed, so that the battery life can be sufficiently ensured. Although polyester has a feature (oxidation resistance) that is difficult to be decomposed by oxygen generated from the positive electrode, it tends to be easily deteriorated with respect to sulfuric acid. On the other hand, in the present embodiment, since the resin containing the epoxy resin and the acrylic resin is held on the base material, it is possible to suppress a decrease in mechanical strength while maintaining the feature that it is difficult to be decomposed by oxygen generated from the positive electrode.

Examples of the polyester in the base material of the resin member according to the present embodiment include polyalkylene terephthalate such as polyethylene terephthalate. The base material may contain a material other than polyester. Examples of materials other than polyester include polyolefins (polyethylene, polypropylene, etc.), polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polycarbonate, and the like. The substrate does not have to contain at least one of these materials (eg, polyolefin).

The polyester content is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more, and 95% by mass or more, based on the total amount of the resin constituting the base material. By mass% or more is extremely preferable, 97% by mass or more is very preferable, and 99% by mass or more is even more preferable. The resin constituting the base material may be substantially made of polyester (substantially, 100% by mass of the resin constituting the base material is polyester).

As the base material, non-woven fabric, woven cloth, etc. can be used. The fibers in the substrate may be oriented. For example, the nonwoven fabric may have an MD direction (mechanical direction) in the manufacture of the nonwoven fabric and a CD direction (width direction) orthogonal to the MD direction. Since the fibers are easily oriented in the MD direction, the MD direction tends to have higher mechanical strength than the CD direction. Therefore, a non-woven fabric having high mechanical strength in the CD direction has high mechanical strength even in a direction in which the mechanical strength is relatively low (CD direction).

The base material may be a porous body having pores. The base material preferably includes a portion having an average pore diameter in the following range. The average pore diameter of the base material is preferably 60 μm or less, more preferably 50 μm or less, further preferably 45 μm or less, and particularly preferably 40 μm or less, from the viewpoint of easily suppressing the outflow of the electrode material. The average pore diameter of the base material is preferably more than 2 μm, more preferably 5 μm or more, further preferably 10 μm or more, particularly preferably 20 μm or more, and extremely preferably 30 μm or more, from the viewpoint that the electrical resistance of the base material is likely to decrease. , 35 μm or more is very preferable. From these viewpoints, the average pore diameter of the base material is preferably more than 2 μm and 60 μm or less. The average pore diameter can be measured by a pore distribution measuring device (for example, AUTO PORE IV 9520 manufactured by Shimadzu Corporation).

Basis weight of the substrate, from the viewpoint of resistance of the substrate is likely to decrease, preferably 200 g / ^{m 2} or less, more preferably 150 g / ^{m 2} or less, more preferably 130 g / ^{m 2} or less, 110g / ^{m 2} or less Especially preferable. The basis weight of the base material is preferably 70 g / m ² or more, more preferably 80 g / m ² or more, and more preferably 90 g, from the viewpoint of easily withstanding deterioration due to contact with sulfuric acid in the battery and deterioration due to oxygen generated during charging. / M ² or more is more preferable, and 100 g / m ² or more is particularly preferable. From these viewpoints, the basis weight of the base material is preferably 70 to 200 g / m ² . The basis weight of the base material means the mass per unit area measured according to JIS L1913.

The resin held on the base material contains an epoxy resin and an acrylic resin. By using an epoxy resin and an acrylic resin, deterioration of sulfuric acid can be suppressed and mechanical strength can be maintained.

Acrylic resin is a resin having a structural unit derived from a monomer having a (meth) acryloyl group. The acrylic resin may be a homopolymer of one kind of monomer, or may be a copolymer of two or more kinds of monomers. The content of the structural unit derived from the monomer having a (meth) acryloyl group in the acrylic resin is 50% by mass or more, 70% by mass or more, or 90% by mass or more based on the total mass of the structural units constituting the acrylic resin. It may be there. The acrylic resin may consist of structural units derived from a monomer having a (meth) acryloyl group.

As the epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, still ben Type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, alicyclic epoxy resin, Examples thereof include diglycidyl ether compounds of polycyclic aromatics (polyfunctional phenols, anthracene, etc.), phosphorus-containing epoxy resins in which a phosphorus compound is introduced therein, and the like.

The content of the epoxy resin is more than 0% by mass and 70% by mass or less based on the total amount of the epoxy resin and the acrylic resin. In this case, by using the epoxy resin and the acrylic resin, the effect of suppressing the deterioration of sulfuric acid and maintaining the mechanical strength is sufficiently exhibited. The content of the epoxy resin is 65 from the viewpoint of easily suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid and from the viewpoint of easily reducing the electric resistance value when the resin member is brought into contact with sulfuric acid. It is preferably mass% or less, more preferably 60% by mass or less, further preferably 55% by mass or less, and particularly preferably 50% by mass or less. The content of the epoxy resin is preferably 45% by mass or less, more preferably 40% by mass or less, further preferably 35% by mass or less, from the viewpoint of further suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid. It is preferable, and 30% by mass or less is particularly preferable. The content of the epoxy resin is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, from the viewpoint of easily suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid. , 20% by mass or more is particularly preferable. The content of the epoxy resin is determined from the viewpoint of further suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid and from the viewpoint of easily reducing the electric resistance value when the resin member is brought into contact with sulfuric acid. 25% by mass or more is preferable, and 30% by mass or more is more preferable. The content of the epoxy resin is preferably 35% by mass or more, more preferably 40% by mass or more, still more preferably 45% by mass or more, from the viewpoint of further reducing the electric resistance value when the resin member is brought into contact with sulfuric acid. , 50% by mass or more is particularly preferable. From these viewpoints, the content of the epoxy resin is preferably more than 0% by mass and 65% by mass or less, and more preferably more than 0% by mass and 40% by mass or less. The content of the epoxy resin can be confirmed by, for example, TG-DTA.

The content of the resin retained on the base material can be measured by the following procedure using a TG-DTA measuring device (for example, TG8120 manufactured by Rigaku Co., Ltd.).
First, a sample obtained by grinding a base material on which a resin is held is weighed in a container (aluminum pan) for a thermogravimetric / differential thermal measurement device (TG-DTA) by about 5.0 mg, and the mass W1 [mg] is recorded. .. In the measuring device, the inert gas (helium) is flowed at a flow rate of 100 ml / min. The temperature is raised from room temperature (for example, 25 ° C.) to 100 ° C. at a heating rate of 10 ° C./min and held at 100 ° C. for 10 minutes to remove water in the sample. Then, the temperature is further raised to 380 ° C. at a heating rate of 10 ° C./min, and the temperature is maintained at 380 ° C. for 20 minutes. Subsequently, the temperature is further raised to 500 ° C. at a heating rate of 10 ° C./min, and the temperature is maintained at 500 ° C. for 5 minutes. The mass loss amount W2 [mg] of the sample in the above heating process is calculated.
On the other hand, as the reference sample, the temperature is similarly raised only for the base material on which the resin is not retained, and the mass reduction amount W3 [mg] of the reference sample in this temperature raising process is calculated.
The resin content is calculated as the ratio of the difference between the mass reduction amount W2 of the sample and the mass reduction amount W3 of the reference sample to the mass W1 of the sample "(W2-W3) / W1 × 100 (%)". ..

The total amount of epoxy resin and acrylic resin is preferably in the following range based on the total mass of the base material. The total amount of the epoxy resin and the acrylic resin is preferably 1% by mass or more, more preferably 3% by mass or more, and 5% by mass or more from the viewpoint of easily suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid. Is more preferable, 7% by mass or more is particularly preferable, 10% by mass or more is extremely preferable, 12% by mass or more is very preferable, and 15% by mass or more is even more preferable. The total amount of the epoxy resin and the acrylic resin is preferably 30% by mass or less, more preferably 25% by mass or less, and more preferably 20% by mass or less from the viewpoint of easily suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid. Is more preferable, and 15% by mass or less is particularly preferable. From these viewpoints, the total amount of the epoxy resin and the acrylic resin is preferably 1 to 30% by mass.

The resin held on the base material may include a resin other than the epoxy resin and the acrylic resin. Examples of the resin other than the epoxy resin and the acrylic resin include rosin-based resin, terpene-based resin, petroleum-based resin, melamine resin, phenol resin, styrene resin and the like.

The total amount of epoxy resin and acrylic resin is preferably in the following range based on the total mass of the resin held on the base material. The total amount of the epoxy resin and the acrylic resin is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more, extremely preferably 95% by mass or more, 97. Mass% or more is very preferable, and 99% by mass or more is even more preferable. The resin held on the base material is substantially composed of an epoxy resin and an acrylic resin (substantially, 100% by mass of the resin held on the base material is an epoxy resin and an acrylic resin). You may.

The resin may be retained on the inner or outer surface of the substrate, or on the surface in the pores of the substrate (collectively, collectively referred to as "on the substrate") and on the substrate. It may be attached to. The resin may be held on a part of the base material or may be held on the entire base material.

The content of the resin held on the base material of the resin member in the active material holding member of the lead storage battery after chemical conversion can be measured by, for example, the following procedure. First, the lead-acid battery after chemical conversion is disassembled, and the electrodes are washed with running water for 12 hours. The electrodes are then dried in air at 45 ° C. for 72 hours. Subsequently, the active material holding member is taken out from the electrode (for example, the boundary position between the upper joint and the active material holding member and the boundary position between the lower joint and the active material holding member are cut off to take out the active material holding member). .. Then, after removing the core metal and the active material from the active material holding member, the content of the resin held on the base material of the resin member is measured.

In the resin member according to the present embodiment, the pores in the range of 0.006 to 0.1 μm measured by the mercury press-fitting method may be less than 10% by volume of the total pore amount.

In the resin member according to the present embodiment, the ratio A / B of the total pore volume A of the pores having a pore diameter of 10 μm or more to the total pore volume B of the pores having a pore diameter of less than 10 μm exceeds 1.40. Good. The total pore volume can be measured with a pore distribution meter (for example, trade name: AUTO PORE IV 9520 manufactured by Shimadzu Corporation). The ratio A / B can be adjusted according to the type or amount of the resin held on the substrate.

The thickness of the resin member (for example, a sheet-shaped resin member) is preferably in the following range. The thickness of the resin member is preferably 0.05 mm or more, more preferably 0.1 mm or more, still more preferably 0.12 mm or more, from the viewpoint of easily suppressing a decrease in mechanical strength when the resin member is brought into contact with sulfuric acid. , 0.15 mm or more is particularly preferable, 0.18 mm or more is extremely preferable, 0.2 mm or more is very preferable, and 0.23 mm or more is even more preferable. The thickness of the resin member is preferably 1 mm or less, more preferably 0.8 mm or less, further preferably 0.6 mm or less, particularly preferably 0.5 mm or less, from the viewpoint of easily reducing the electrical resistance of the resin member. 4 mm or less is extremely preferable, 0.3 mm or less is very preferable, and 0.25 mm or less is even more preferable. From these viewpoints, the thickness of the resin member is preferably 0.05 to 1 mm. As the thickness of the resin member, the average value of the thickness may be used. The average thickness can be measured by the method described in Examples.

The tubular portion of the active material holding member according to the present embodiment has an internal space for accommodating the active material. The cross-sectional shape perpendicular to the axial direction (longitudinal direction) of the tubular portion may be a circle, an ellipse, a quadrangle with rounded corners, or the like. The length of the tubular portion is, for example, 160 to 650 mm. The outer diameter of the tubular portion is, for example, 5 to 12 mm. The inner diameter of the tubular portion is, for example, 5 to 10 mm. The active material holding member according to the present embodiment may have a tubular portion, or may have a portion other than the tubular portion.

The active material holding member according to the present embodiment is for holding an active material by arranging a plurality of (for example, 2 to 19) tubular parts of the active material holding member in a direction orthogonal to the axial direction of the tubular part. A group of tubes may be formed. In the active material holding tube group, the tubular portions of the plurality of active material holding members are arranged side by side with each other. A structure in which a plurality of tubular portions are arranged side by side may be obtained by arranging tubular portions that are separate bodies from each other, or by forming a plurality of through holes between the base materials facing each other. May be done. Connecting portions such as stitches (sewn portions) may be arranged between the adjacent tubular portions. Examples of the type of the active material holding member include a spiral type and a gauntlet type. In the spiral type, the tubular portion is formed by spirally winding the resin sheet. In the gauntlet type, a tubular portion is formed by joining (for example, suturing) resin sheets facing each other. In the active material holding member, the resin sheet is wound around the tubular portion in a state where the pair of sides of the resin sheet having a pair of sides facing each other are oriented in the axial direction of the tubular portion. A shaped portion may be formed. In the active material holding member, a tubular portion may be formed by winding the resin sheet in a spiral shape.

"Spiral" means traveling in the extending direction of the central axis while orbiting around the central axis extending in a predetermined direction. "Swirl" means orbiting in the same plane. For example, in the case of a spiral shape, the tubular portion extends as the resin sheet is wound, whereas in the case of a spiral shape, the tubular portion becomes thicker as the resin sheet is wound, but the tubular portion. Does not stretch. The winding direction (counterclockwise or clockwise) in the spiral case means the direction of rotation of the resin sheet with respect to the central axis. In the case of a spiral shape, the winding direction (counterclockwise or clockwise) means the winding direction when the resin sheet is wound from the inner layer to the outer layer of the tubular portion. The resin sheet may be wound at least once, may be wound more than one turn, and may be wound a plurality of times.

When the base material contains a non-woven fabric in the active material holding member provided with the tubular portion, it is preferable that the MD direction and the CD direction of the non-woven fabric are inclined with respect to the axial direction of the tubular portion. The inclination angle of the tubular portion in the MD direction or the CD direction with respect to the axial direction is preferably in the following range from the viewpoint of easily suppressing the influence of the mechanical strength caused by the fiber orientation and thus ensuring a sufficient battery life. The inclination angle is preferably more than 0 °, more preferably 10 ° or more, further preferably 20 ° or more, particularly preferably 30 ° or more, extremely preferably 40 ° or more, and very preferably 43 ° or more. The inclination angle is preferably less than 90 °, more preferably 80 ° or less, further preferably 70 ° or less, particularly preferably 60 ° or less, extremely preferably 50 ° or less, and very preferably 47 ° or less. From these viewpoints, the inclination angle is preferably more than 0 ° and less than 90 °, more preferably 10 to 80 °, still more preferably 43 to 47 °. When the inclination angle is 45 °, it is presumed that the influence of mechanical strength due to fiber orientation is most easily suppressed.

The electrode according to the present embodiment may have a core metal (current collector) inserted in an active material holding member (for example, a tubular portion). The electrode according to the present embodiment may have an active material holding member having a tubular portion, a core metal inserted in the tubular portion, and an active material filled between the tubular portion and the core metal. The electrode according to this embodiment may have a group of tubes for holding an active material.

The core metal is a rod-shaped member inserted into the active material holding member (for example, a tubular portion), and extends in the axial direction of the tubular portion, for example, at the center of the tubular portion. The core metal can be obtained by casting, for example, by a pressure casting method. The constituent material of the core metal may be any conductive material, and examples thereof include lead alloys such as lead-calcium-tin alloys and lead-antimony-arsenic alloys. The lead alloy may contain selenium, silver, bismuth and the like. The cross-sectional shape perpendicular to the axial direction (longitudinal direction) of the core metal may be circular, elliptical, or the like. The length of the core metal is, for example, 160 to 650 mm. The diameter of the core metal is, for example, 2.0 to 4.0 mm.

The lead-acid battery according to the present embodiment may include an electric tank for accommodating electrodes (positive electrode and negative electrode). The electrodes may form a group of electrodes. For example, in the electrode group, positive electrodes and negative electrodes are alternately arranged via separators. Silica particles do not have to be arranged between the positive electrode and the negative electrode. The inside of the battery case may be filled with an electrolytic solution. The electrolytic solution may contain aluminum ions, sodium ions, lithium ions and the like. The electrolytic solution does not have to contain silica particles.

The electrode (positive electrode or negative electrode) after chemical conversion has an electrode material (positive electrode material or negative electrode material) containing an active material. Further, the electrode (positive electrode or negative electrode) may have a current collector. The electrode material can be held by an active material holding member, a current collector, or the like. The positive electrode material is held by, for example, the active material holding member according to the present embodiment. The negative electrode material may be held by any of an active material holding member, a current collector, and the like.

The positive electrode material contains a positive electrode active material after chemical conversion. The chemicalized positive electrode material can be obtained, for example, by chemicalizing an unchemicald positive electrode material containing a raw material for the positive electrode active material. Examples of the method for obtaining the positive electrode material after chemical conversion include a method in which the raw material of the positive electrode active material is directly charged into the active material holding member (for example, a tubular portion) and then formed, and a method of aging and drying the positive electrode material paste containing the raw material of the positive electrode active material. Then, a method of forming the unchemicald positive electrode material after obtaining the unchemicald positive electrode material can be mentioned. Examples of the raw material for the positive electrode active material include lead powder and lead tan. Examples of the positive electrode active material in the positive electrode material after chemical conversion include lead dioxide and the like.

The positive electrode material can further contain additives as needed. Examples of the additive for the positive electrode material include short reinforcing fibers. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers (PET fibers) and the like.

The negative electrode material contains the negative electrode active material after chemical conversion. The chemical negative electrode material can be obtained, for example, by chemicalizing an unchemicald negative electrode material containing a raw material for the negative electrode active material. The negative electrode material after chemical conversion can be obtained, for example, by aging and drying a negative electrode material paste containing a raw material for the negative electrode active material to obtain an unchemicald negative electrode material, and then chemicalizing the unchemicald negative electrode material. Examples of the raw material for the negative electrode active material include lead powder and the like. Examples of the negative electrode active material in the negative electrode material after chemical conversion include porous spongy lead (Sponge Lead) and the like.

The negative electrode material can further contain additives as needed. Examples of the additive for the negative electrode material include barium sulfate, reinforcing short fibers, and a carbon material (carbon conductive material). As the reinforcing short fiber, the same reinforcing short fiber as the positive electrode material can be used.

Examples of carbon materials include carbon black and graphite. Examples of carbon black include furnace black (Ketjen black (registered trademark), etc.), channel black, acetylene black, thermal black, and the like.

The material of the separator is not particularly limited as long as it is a material that blocks the electrical connection between the positive electrode and the negative electrode and allows the electrolytic solution to permeate. Examples of the material of the separator include microporous polyethylene; a mixture of glass fiber and synthetic resin.

The resin member, active material holding member, and electrode according to the present embodiment are preferably used in a liquid lead-acid battery (resin member, active material holding member, and electrode for a liquid lead-acid battery), and lead according to the present embodiment. The storage battery is preferably a liquid lead storage battery. In general, in a liquid lead-acid battery, the entire electrode tends to be immersed in the electrolytic solution, and the amount of the electrolytic solution tends to be larger than that of a control valve type lead-acid battery or the like. In this case, since the discharge capacity is not easily regulated by the amount of the electrolytic solution, the discharge capacity tends to be increased. However, in a liquid lead-acid battery, the stratification of the electrolytic solution increases the concentration of sulfuric acid in the region below the electrode, and the resin member below the active material holding member in the electrode tends to deteriorate. Further, in a liquid lead-acid battery, as the deterioration over time (including deterioration due to the charge / discharge cycle) progresses, the active material (for example, the positive electrode active material) becomes muddy, and the active material easily leaks out. Become. In these cases, if the mechanical strength of the resin member is reduced when it is brought into contact with sulfuric acid, the active material leaks significantly. On the other hand, in the resin member according to the present embodiment, since it is possible to suppress a decrease in the mechanical strength of the resin member when it is brought into contact with sulfuric acid, it is necessary to utilize the advantages of the liquid lead-acid battery while suppressing the leakage of the active material. Can be done.

An example of the lead storage battery according to the present embodiment will be described with reference to FIGS. 1 and 2. 1 and 2 are schematic cross-sectional views showing an example of a lead storage battery. In FIG. 1, positive electrodes and negative electrodes are alternately arranged via separators from the front side to the back side of the drawing. FIG. 1 (b) is an enlarged view showing a region P of FIG. 1 (a). In FIG. 1A, the details inside the tubes and the details of the portions where the tubes are adjacent to each other are omitted. The lead-acid batteries shown in FIGS. 1 and 2 are provided with an electric tank extending in the vertical direction, and FIG. 2 shows a positive electrode when the lead-acid battery is viewed from above in the vertical direction (above in the height direction of the electric tank). , The laminated structure of the negative electrode and the separator is shown.

The lead-acid battery 100 shown in FIGS. 1 and 2 is connected to an electrode group 110, an electric tank 120 accommodating the electrode group 110, connecting

members

130a and 130b connected to the electrode group 110, and connecting

members

130a and 130b. The

electrode columns

140a and 140b are provided, a liquid port plug 150 for closing the liquid injection port of the electric tank 120, and a support member 160 connected to the electric tank 120.

The electrode group 110 includes a plurality of positive electrodes 10, a plurality of negative electrodes 20, and a plurality of separators 30. The positive electrode 10 and the negative electrode 20 are alternately arranged via the separator 30. The space around the positive electrode 10 between the separators 30 is filled with the electrolytic solution 40.

The positive electrode 10 is, for example, a plate-shaped electrode (positive electrode plate), and includes a plurality of tubes (active material holding member) 10a for holding the active material, a core metal (current collector) 10b, a positive electrode material 10c, and a lower portion. It has a collective punishment 10d, an upper collective punishment 10e, and an ear portion 10f. The tube 10a of the positive electrode 10 is formed of a tubular portion capable of accommodating the positive electrode material 10c containing an active material.

The plurality of tubes 10a are arranged side by side with each other to form the active material holding tube group 50. That is, the positive electrode 10 has the active material holding tube group 50. Each tube 10a extends in the height direction (vertical direction) of the electric tank 120. The core metal 10b extends in the axial direction of the tube 10a at the center of the tube 10a. The positive electrode material 10c is filled between the tube 10a and the core metal 10b.

The lower punishment 10d is connected to one end of the tube 10a (lower end in the figure), and the upper punishment 10e is connected to the other end of the tube 10a (upper end in the figure). The lower joint 10d and the upper joint 10e are in contact with the tube 10a and the core metal 10b and the positive electrode material 10c arranged in the tube 10a, and hold the tube 10a, the core metal 10b, and the positive electrode material 10c. The lower collective punishment 10d is attached to the bottom end of the battery case 120 in the tube 10a (the end on one end of the tube 10a). The lower joint 10d is fitted to the end of the tube 10a, and has a base extending in a direction orthogonal to the axial direction of the tube 10a and a plurality of fittings connected to the base and fitted to the end of the tube 10a. It has a joint part. The fitting portion is formed with a recess into which the end portion of the core metal 10b is inserted. The upper collective punishment 10e is attached to the upper end of the electric tank 120 in the tube 10a (the other end of the tube 10a).

One end of the selvage 10f (lower end in the figure) is connected to the upper collective punishment 10e, and the other end of the selvage 10f (upper end in the figure) is connected to the connecting member 130a. The core metal 10b housed in the tube 10a is electrically connected to the pole pillar 140a via the upper connecting seat 10e, the selvage portion 10f, and the connecting member 130a.

The support member 160 has a plurality of protrusions 160a extending in the axial direction (longitudinal direction, for example, the height direction of the electric tank 120) of the tube 10a, and the lower joint 10d is fixed in contact with the plurality of protrusions 160a. ing. That is, the support member 160 supports the portion on the bottom surface side of the electric tank 120 in the lower collective punishment 10d by each protrusion 160a.

The negative electrode 20 is, for example, a plate-shaped negative electrode plate, for example, a paste type negative electrode plate. The negative electrode 20 has a negative electrode current collector and a negative electrode material held by the negative electrode current collector. As the negative electrode current collector, a plate-shaped current collector can be used. The composition of the negative electrode current collector and the core metal 10b of the positive electrode 10 may be the same or different from each other. The negative electrode 20 is electrically connected to the pole pillar 140b via the connecting member 130b.

The method for manufacturing a lead-acid battery according to the present embodiment includes an assembly step of assembling a component including an electrode having an active material holding member to obtain a lead-acid battery. In the assembling step, for example, a non-chemical positive electrode and a non-chemical negative electrode are laminated, and the current collecting portions of electrodes having the same polarity are welded with a strap to obtain an electrode group. This group of electrodes is arranged in the battery case to produce an unchemical battery. The unchemical positive electrode and the unchemical negative electrode may be laminated via a separator.

The lead-acid battery manufacturing method according to the present embodiment may include an active material holding member manufacturing step of manufacturing an active material holding member using a resin member before the assembling step. The active material holding member manufacturing step may include a molding step of molding a base material containing polyester into a tubular shape to obtain a tubular portion. A resin containing an epoxy resin and an acrylic resin may or may not be held on the base material of the resin member in the process of manufacturing the active material holding member. As a first aspect, in the molding step, the tubular portion may be formed by spirally or spirally winding the resin sheet. As a second aspect, in the molding step, a tubular portion may be formed by joining resin sheets facing each other. As a third aspect, in the molding step, the resin sheet is wound in the circumferential direction of the tubular portion in a state where the pair of sides of the resin sheet having a pair of opposite sides face each other in the axial direction of the tubular portion. As a result, a tubular portion may be formed. In the active material holding member manufacturing step, after the molding step, a group of active material holding tubes may be obtained by arranging a plurality of tubular portions in a direction orthogonal to the axial direction of the tubular portion.

The method for manufacturing a lead-acid battery according to the present embodiment includes a resin supporting step of holding a resin containing an epoxy resin and an acrylic resin on a base material before or after the assembling step and before or after the active material holding member manufacturing step. Good. In the resin supporting step, the resin can be held on the base material by impregnating the base material with an emulsion in which the resin is dispersed in water. After impregnating the base material with the emulsion, it may be dried at 60 to 130 ° C. for 1 to 3 hours.

The method for manufacturing a lead-acid battery according to the present embodiment may include an electrode manufacturing step for manufacturing an electrode having an active material holding member. The electrode manufacturing step includes a positive electrode manufacturing step and a negative electrode manufacturing step. The case where the positive electrode has an active material holding member will be described below.

In the positive electrode manufacturing step, a positive electrode having a core metal inserted in an active material holding member (for example, a tubular portion) and a positive electrode material filled between the active material holding member and the core metal is obtained. In the positive electrode manufacturing step, for example, after arranging the core metal in the tubular portion, a raw material for a positive electrode active material or the like is filled between the core metal and the tubular portion, and the lower end of the tubular portion is closed with a lower joint. Thereby, a positive electrode having an unchemicald positive electrode material can be obtained. In the positive electrode manufacturing step, the upper end of the tubular portion may be closed with an upper joint.

In the negative electrode manufacturing step, for example, a negative electrode material paste containing a raw material for a negative electrode active material is filled in a negative electrode current collector (for example, a current collector lattice (cast lattice body, expanded lattice body, etc.)), and then aged and dried. Therefore, a negative electrode having a non-chemical negative electrode material can be obtained.

The method for manufacturing a lead storage battery according to the present embodiment may include a chemical conversion treatment step for performing a chemical conversion treatment on the positive electrode and the negative electrode. The chemical conversion treatment step may be carried out after the assembling step, or may be carried out in the electrode manufacturing step before the assembling step (tank chemical conversion). In the chemical conversion treatment step, for example, the chemical conversion treatment is performed by applying a direct current while the positive electrode and the negative electrode are in contact with the electrolytic solution. A lead storage battery can be obtained by adjusting the specific gravity of the electrolytic solution after chemical conversion to an appropriate specific gravity.

The electric vehicle (for example, an electric vehicle) or the power supply device according to the present embodiment includes the lead storage battery according to the present embodiment. The method for manufacturing an electric vehicle or a power supply device according to the present embodiment includes a step of obtaining a lead-acid battery by the method for manufacturing a lead-acid battery according to the present embodiment. The method for manufacturing an electric vehicle or a power supply device according to the present embodiment is, for example, a step of obtaining a lead-acid battery by the method for manufacturing a lead-acid battery according to the present embodiment and an electric vehicle or a power supply device by assembling a component including the lead-acid battery. It is equipped with a process to obtain. Examples of the electric vehicle include a forklift and a golf cart. Examples of the power supply device include UPS, disaster prevention (emergency) wireless power supply, telephone power supply, and the like. According to the present embodiment, a lead storage battery for an electric vehicle (for example, a lead storage battery for an electric vehicle) is provided, and for example, a lead storage battery for a forklift is provided. According to the present embodiment, a lead storage battery for a power supply device is provided.

In lead-acid batteries for electric vehicles, it is easy to design a large electrode height in the battery height direction. Therefore, since the sulfuric acid in the electrolytic solution tends to settle downward, the concentration of the sulfuric acid in the region below the electrode increases due to the stratification of the electrolytic solution, and the resin member below the active material holding member in the electrode tends to deteriorate. In this case, if the mechanical strength of the resin member is reduced when it is brought into contact with sulfuric acid, the active material leaks significantly. On the other hand, the lead-acid battery according to the present embodiment can suppress a decrease in mechanical strength of the resin member when it comes into contact with sulfuric acid, and thus can suppress leakage of an active material. Therefore, it can be suitably used in an electric vehicle. it can.

Hereinafter, the content of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<Making a resin sheet>
(Example 1)
Emulsion containing acrylic resin (manufactured by DIC Corporation, AJ-1800) and epoxy resin (manufactured by DIC Corporation, EN-0270) is mixed with polyester non-woven fabric (including polyethylene terephthalate. Average pore diameter: 38 μm, grain size: 108 g / m ² ) was impregnated for 1 minute. Then, it was dried in a constant temperature bath at 100 ° C. for 1 hour to obtain a resin sheet containing a resin held on a substrate. The total amount of epoxy resin and acrylic resin held on the base material is 15% by mass based on the total mass of the base material, and the mass ratio of epoxy resin and acrylic resin is 20:80 (epoxy resin: acrylic resin). It was.

(Example 2)
A resin sheet was prepared in the same manner as in Example 1 except that the amounts of the epoxy resin and the acrylic resin used in the emulsion were changed. The total amount of epoxy resin and acrylic resin held on the base material is 15% by mass based on the total mass of the base material, and the mass ratio of epoxy resin and acrylic resin is 25:75 (epoxy resin: acrylic resin). It was.

(Example 3)
A resin sheet was prepared in the same manner as in Example 1 except that the amounts of the epoxy resin and the acrylic resin used in the emulsion were changed. The total amount of epoxy resin and acrylic resin held on the base material is 15% by mass based on the total mass of the base material, and the mass ratio of epoxy resin and acrylic resin is 30:70 (epoxy resin: acrylic resin). It was.

(Example 4)
A resin sheet was prepared in the same manner as in Example 1 except that the amounts of the epoxy resin and the acrylic resin used in the emulsion were changed. The total amount of epoxy resin and acrylic resin held on the base material is 15% by mass based on the total mass of the base material, and the mass ratio of epoxy resin and acrylic resin is 50:50 (epoxy resin: acrylic resin). It was.

(Comparative Example 1)
A resin sheet was prepared in the same manner as in Example 1 except that the emulsion was changed to use only acrylic resin without using epoxy resin. The amount of acrylic resin held on the base material was 15% by mass based on the total mass of the base material, and the mass ratio of epoxy resin to acrylic resin was 0: 100 (epoxy resin: acrylic resin).

(Comparative Example 2)
A resin sheet was prepared in the same manner as in Example 1 except that the amounts of the epoxy resin and the acrylic resin used in the emulsion were changed. The total amount of epoxy resin and acrylic resin held on the base material is 15% by mass based on the total mass of the base material, and the mass ratio of epoxy resin and acrylic resin is 75:25 (epoxy resin: acrylic resin). It was.

(Comparative Example 3)
A resin sheet was prepared in the same manner as in Example 1 except that the emulsion was changed to use only an epoxy resin without using an acrylic resin. The amount of the epoxy resin held on the base material was 15% by mass based on the total mass of the base material, and the mass ratio of the epoxy resin and the acrylic resin was 100: 0 (epoxy resin: acrylic resin).

<Thickness of resin sheet>
The thickness of the resin sheet was measured at 10 points with a caliper, and the average value of the 10 points was obtained as the thickness of the resin sheet. The results are shown in Table 1.

<Evaluation of pores>
In the resin sheets of Examples 1 to 4, the pores in the range of 0.006 to 0.1 μm measured by the mercury intrusion method were less than 10% by volume of the total pore amount.
In the resin sheets of Examples 1 to 4, the ratio A / B of the total pore volume A of the pores having a pore diameter of 10 μm or more to the total pore volume B of the pores having a pore diameter of less than 10 μm exceeds 1.40. It was. The pore volume ratio of the resin sheet was calculated based on the pore distribution. The pore distribution of the resin sheet was measured using a pore distribution meter (manufactured by Shimadzu Corporation, trade name: AUTO PORE IV 9520). For the pore volume ratio of the resin sheet, the volume of each pore obtained from the measurement result of the pore distribution is "total pore volume of pores having a pore diameter of 10 μm or more" and "total pore volume having a pore diameter of less than 10 μm". It was separated into "pore volume" and calculated based on "total pore volume of pores having a pore diameter of 10 μm or more" / "total pore volume of pores having a pore diameter of less than 10 μm".

<Sulfuric acid deterioration evaluation>
Two sheets, sheet A and sheet B, were prepared as the above-mentioned resin sheets. Sheet B was put into sulfuric acid having a specific gravity of 1.330 (20 ° C.). After leaving the sheet for 12 hours so that sulfuric acid permeates into the sheet, the sheet was held in a constant temperature bath at 70 ° C. and left for 3 weeks. Then, the sheet was thoroughly washed with running water and then dried in a dryer at 60 ° C. for 24 hours.

A 20 mm × 70 mm test piece was cut out from the sheet A not immersed in sulfuric acid and the sheet B immersed in sulfuric acid. The tensile strength of the test piece in the CD direction of the non-woven fabric was measured using an autograph (EZ-FX, manufactured by Shimadzu Corporation). The distance between the chucks was set to 20 mm, and the tensile speed was set to 5 mm / min. The strength maintenance rate [%] was measured from the following formula. The results are shown in Table 1.
Strength retention rate = [(tensile strength of sheet B) / (tensile strength of sheet A)] × 100

<Measurement of electrical resistance>
A lead plate of 70 mm × 70 mm × 1 mm (three or more types of plates specified in JIS H 2105) was placed as a current electrode in the current electrode chamber of the electric resistance test tank described in SBA S0402. A spacer for fixing the test piece was inserted at the place where the test piece was inserted, and then sulfuric acid having a specific gravity of 1.280 (20 ° C.) was added to a height of 10 mm from the upper edge of the test battery. Then, a mercuric sulfate electrode containing a saturated aqueous potassium sulfate solution as an internal solution was placed in a voltage electrode chamber, and then allowed to stand still for 1 hour while maintaining 25 ° C. Then, 1000 mA was energized for 1 minute using an electrochemical measuring device (HZ-5000 manufactured by Hokuto Denko Co., Ltd.), and an electric resistance value R1 was obtained after 1 minute.
Next, five test pieces of 70 mm × 70 mm were cut out from the above-mentioned resin sheet, and the test pieces were immersed in sulfuric acid having a specific gravity of 1.280 (20 ° C.) at 25 ° C. for 24 hours. Then, one of the above-mentioned test pieces was inserted into a place where the test piece was inserted with the test piece sandwiched between spacers and fixed. At this time, the area of the resistance measurement point on the test piece was 6 cm ² . Using the above-mentioned electrochemical measuring device, 1000 mA was energized for 1 minute, and the electric resistance value after 1 minute was obtained. This measurement was carried out on the above-mentioned five test pieces, and the average value R2 of the five electric resistance values was obtained.
Then, the electric resistance value R (unit: mΩ / cm ² ) was obtained by the following formula. The results are shown in Table 1.
R = (R2-R1) / 6 × 1000

10 ... Positive electrode (electrode), 20 ... Negative electrode (electrode), 10a ... Tube (active material holding member), 100 ... Lead storage battery.

Claims

A resin member used for an active material holding member.
A base material containing polyester and a resin held on the base material are provided.
The resin contains an epoxy resin and an acrylic resin.
A resin member having a content of the epoxy resin of more than 0% by mass and 70% by mass or less based on the total amount of the epoxy resin and the acrylic resin.
The resin member according to claim 1, wherein the content of the epoxy resin is more than 0% by mass and 40% by mass or less based on the total amount of the epoxy resin and the acrylic resin.
The resin member according to claim 1 or 2, which has a thickness of 0.05 to 1 mm.
The resin member according to any one of claims 1 to 3, wherein the total amount of the epoxy resin and the acrylic resin is 1 to 30% by mass based on the total mass of the base material.
An active material holding member including the resin member according to any one of claims 1 to 4.
A tubular portion including the resin member is provided.
The substrate contains a non-woven fabric
The active material holding member according to claim 5, wherein the MD direction and the CD direction of the nonwoven fabric are inclined with respect to the axial direction of the tubular portion.
An electrode having the active material holding member according to claim 6 and the active material held by the active material holding member.
Equipped with positive and negative electrodes
The lead-acid battery, wherein at least one selected from the group consisting of the positive electrode and the negative electrode is the electrode according to claim 7.
The lead-acid battery according to claim 8, further comprising a separator arranged between the positive electrode and the negative electrode.
An electric vehicle comprising the lead-acid battery according to claim 8 or 9.