JP2020123482A - Lead-acid battery separator, lead-acid battery and manufacturing method thereof, and adhesion improving method - Google Patents

Abstract

To provide a lead-acid battery separator capable of improving the adhesion between an electrode and a separator.SOLUTION: A lead-acid battery separator according to a first embodiment includes a swelling agent and can swell by contact with sulfuric acid. The lead-acid battery separator according to a second embodiment is a swelling body including a swelling agent and sulfuric acid.SELECTED DRAWING: None

Description

The present invention relates to a lead storage battery separator, a lead storage battery, a method for manufacturing the same, and a method for improving adhesion.

The lead storage battery has a structure in which a separator and an electrode are laminated. As a lead-acid battery separator, a separator containing glass fiber can be used (see, for example, Patent Document 1 below).

JP-A-4-106869

By the way, a lead-acid battery separator is required to have high adhesion between the electrode and the separator from the viewpoint of obtaining excellent battery characteristics.

It is an object of the present invention to provide a lead storage battery separator that can improve the adhesion between the electrode and the separator. It is another object of the present invention to provide a lead acid battery including the lead acid battery separator and a method for manufacturing the same. A further object of the present invention is to provide a method for improving adhesion, which can improve the adhesion between the lead storage battery electrode and the separator.

One aspect of the present invention provides a lead storage battery separator that contains a swelling agent and is swellable by contact with sulfuric acid. Another aspect of the present invention provides a lead storage battery separator, which is a swelling body containing a swelling agent and sulfuric acid.

Another aspect of the present invention provides a lead storage battery which includes an electrode and the above-described lead storage battery separator, and the lead storage battery separator is laminated on the electrode.

Another aspect of the present invention provides a method for producing a lead storage battery, which comprises a step of bringing sulfuric acid into contact with a separator that is laminated on an electrode and that contains a swelling agent.

Another aspect of the present invention provides a method for improving adhesion, in which the swelling agent is used to improve the adhesion between the lead storage battery electrode and the separator.

According to these lead-acid battery separators, lead-acid batteries and manufacturing methods thereof, and adhesion improving methods, it is possible to improve the adhesion between the electrode and the separator, and to improve the battery characteristics of the lead-acid battery. it can.

According to the present invention, the adhesion between the electrode and the separator can be improved, and the battery characteristics of the lead storage battery can be improved.

It is a figure which shows the result of a swelling test.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

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

A first aspect of the lead-acid battery separator according to the present embodiment contains a swelling agent and is swellable by contact with sulfuric acid. A second aspect of the lead-acid battery separator according to the present embodiment is a swollen body (swelled body) containing a swelling agent and sulfuric acid. The lead acid battery separator according to the second aspect can be obtained by bringing the lead acid battery separator according to the first aspect into contact with sulfuric acid. When the lead acid battery separator swells due to contact with sulfuric acid, the thickness of the separator increases, for example, 1.5 times or more.

According to the present embodiment, the sulfuric acid is brought into contact with the lead storage battery separator containing the swelling agent so that the separator swells, and thus the adhesion between the electrode and the separator can be improved, and the battery of the lead storage battery can be It is possible to improve characteristics (for example, discharge characteristics). According to this embodiment, the pressure applied to the laminated body of the electrode and the separator can be preferably maintained (high group thickness retention).

The adhesion improving method according to the present embodiment is a method for improving the adhesion between the lead storage battery electrode and the separator, and uses a swelling agent to improve the adhesion between the lead storage battery electrode and the separator.

The lead storage battery according to the present embodiment includes an electrode and a lead storage battery separator according to the present embodiment (hereinafter, simply referred to as “separator” in some cases), and the separator is laminated on the electrode. The lead storage battery according to the present embodiment includes a positive electrode and a negative electrode as electrodes. The lead storage battery according to the present embodiment may include a plurality of positive electrodes and/or a plurality of negative electrodes. The separator according to this embodiment may be in contact with at least one selected from the group consisting of a positive electrode and a negative electrode. Other layers may be disposed between the separator according to this embodiment and the positive electrode and/or the negative electrode. The lead-acid battery according to this embodiment may include an electrolytic solution containing sulfuric acid (eg, a sulfuric acid aqueous solution).

The separator according to this embodiment may be arranged between the positive electrode and the negative electrode, and at least a part of the separator may be arranged between the positive electrode and the negative electrode. The separator may be bag-shaped. The separator may wrap at least one selected from the group consisting of a positive electrode and a negative electrode. The separator does not have to surround the positive electrode and the negative electrode.

The separator according to the present embodiment contains a swelling agent. When the separator contains the swelling agent, the separator can be swollen when the separator comes into contact with sulfuric acid. As the swelling agent, a compound that does not swell the separator when it contacts water without contacting sulfuric acid can be used. Aluminum sulphate or the like can be used as the swelling agent.

The content of the swelling agent is preferably within the following range based on the total mass of the separator. The content of the swelling agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and more preferably 1% by mass, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator easily swells. The above is more preferable, 2% by mass or more is particularly preferable, 3% by mass or more is extremely preferable, and 3.5% by mass or more is very preferable. The content of the swelling agent is preferably 10% by mass or less, more preferably 8% by mass or less, further preferably 7% by mass or less, particularly preferably 6% by mass or less, from the viewpoint of easily obtaining excellent liquid absorbing property of the separator. It is preferably 5% by mass or less, and very preferably 4% by mass or less. From these viewpoints, the content of the swelling agent is preferably 0.1 to 10% by mass.

The separator according to this embodiment can contain glass fibers. As the glass fiber, a commercially available glass fiber that is usually used for a lead storage battery separator can be used. The glass fiber preferably contains alkali glass. The glass fiber may include C glass. The glass fiber of the C glass composition has excellent acid resistance. As the glass fiber, one kind or two or more kinds of fibers may be mixed and used for obtaining a glass sheet having a desired pore size.

When the separator contains glass fiber, the content of glass fiber is preferably within the following range based on the total mass of the separator. The content of the glass fiber is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, particularly preferably 80% by mass or more, from the viewpoint of easily improving the adhesion between the electrode and the separator. It is preferably 85% by mass or more and very preferably. The content of the glass fiber is preferably 99% by mass or less, more preferably 97% by mass or less, and further preferably 95% by mass or less, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator is likely to swell. , 92 mass% or less is particularly preferable, and 90 mass% or less is extremely preferable. From these viewpoints, the glass fiber content is preferably 50 to 99 mass %.

When the separator contains glass fiber, the content of glass fiber is preferably within the following range with respect to 100 parts by mass of the swelling agent. The content of the glass fiber is preferably 1000 parts by mass or more, more preferably 1500 parts by mass or more, further preferably 2000 parts by mass or more, particularly preferably 2500 parts by mass or more, from the viewpoint of easily improving the adhesion between the electrode and the separator. preferable. The content of the glass fiber is preferably 5,000 parts by mass or less, more preferably 3,000 parts by mass or less, and further preferably 2700 parts by mass or less, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator easily swells. .. From these viewpoints, the content of the glass fiber is preferably 1000 to 5000 parts by mass.

The separator according to the present embodiment can contain an organic binder, and may contain glass fiber and an organic binder. When the separator contains an organic binder, the swelling agent unwinds the entanglement of the organic binder, so that the separator is likely to swell.

As the organic binder, those having excellent acid resistance and water resistance are preferable, and examples thereof include an olefin resin, an acrylic resin, a urethane resin, and a styrene resin. As the organic binder, a thermoplastic resin introduced with a hydrophilic group such as a sulfo group or a carboxyl group may be used from the viewpoint of easily improving the affinity between the separator and the electrolytic solution. The organic binder preferably contains at least one selected from the group consisting of an olefin resin and a styrene resin from the viewpoint of easily achieving both excellent mechanical strength and liquid retaining property of the electrolytic solution. The organic binder may contain at least one selected from the group consisting of polypropylene and polyethylene from the viewpoint of easily obtaining excellent acid resistance and water resistance, and from the viewpoint of easily obtaining excellent affinity of the separator for sulfuric acid. It is more preferable to include polypropylene. The organic binders may be used alone or in combination of two or more.

The content of the organic binder is preferably within the following range based on the total mass of the separator. The content of the organic binder is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and 6% by mass or more from the viewpoint of easily improving the adhesion between the electrode and the separator. Particularly preferable, and 7% by mass or more is extremely preferable. The content of the organic binder is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator is likely to swell. The content is preferably 9% by mass or less, particularly preferably 8% by mass or less. From these viewpoints, the content of the organic binder is preferably 1 to 20% by mass.

When the separator contains an organic binder, the content of the organic binder is preferably within the following range with respect to 100 parts by mass of the swelling agent. From the viewpoint of easily improving the adhesion between the electrode and the separator, the content of the organic binder is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, further preferably 150 parts by mass or more, and 200 parts by mass or more. Particularly preferable is 225 parts by mass or more, and it is extremely preferable. The content of the organic binder is preferably 500 parts by mass or less, more preferably 400 parts by mass or less, and further preferably 350 parts by mass or less, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator is likely to swell. It is particularly preferably 300 parts by mass or less, and particularly preferably 250 parts by mass or less. From these viewpoints, the content of the organic binder is preferably 50 to 500 parts by mass.

When the separator contains the glass fiber and the organic binder, the content of the organic binder is preferably within the following range with respect to 100 parts by mass of the glass fiber. The content of the organic binder is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and 7 parts by mass or more from the viewpoint of easily improving the adhesion between the electrode and the separator. Particularly preferable, and 9 parts by mass or more is extremely preferable. The content of the organic binder is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator easily swells. It is preferably 10 parts by mass or less, and particularly preferably 10 parts by mass or less. From these viewpoints, the content of the organic binder is preferably 1 to 30 parts by mass.

The total thickness (film thickness) of the separator according to this embodiment is preferably within the following range. The total thickness of the separator is preferably 0.1 mm or more, more preferably 0.3 mm or more, and 0.4 mm or more from the viewpoint of easily manufacturing the separator by a general papermaking method and easily holding a necessary amount of the electrolytic solution. The above is more preferable, 0.5 mm or more is particularly preferable, 0.8 mm or more is extremely preferable, 1.0 mm or more is very preferable, 1.2 mm or more is further preferable, 1.5 mm or more is further preferable, 1.5 mm Is particularly preferable, and 1.7 mm or more is extremely preferable. The total thickness of the separator is preferably 2.5 mm or less, more preferably 2.0 mm or less, and more preferably 1.8 mm or less from the viewpoint that the electrodes (electrode plates etc.) used can be increased and the capacity of the lead storage battery can be easily increased. More preferably, 1.7 mm or less is particularly preferable. From these viewpoints, the total thickness of the separator is preferably 0.1 to 2.5 mm.

The method for producing the separator according to the present embodiment is not particularly limited, and includes wet papermaking, dry papermaking and the like. Among these, it is preferable to adopt a papermaking method based on a wet method (wet papermaking). This manufacturing method is a swelling agent, a glass fiber, a slurry preparation step of preparing a slurry containing an organic binder, a papermaking step of papermaking the slurry to prepare a papermaking article, and a papermaking article using a pressure machine. The method includes a compressed body producing step of producing a compressed body by compressing in the thickness direction, and a heat treatment step of heat treating the compressed body at a temperature equal to or higher than the softening point of the resin (organic binder), if necessary. By this method, a low cost and thin lead acid battery separator can be easily manufactured. Here, the paper product obtained by paper-making the slurry is a sheet-shaped or mat-shaped molded product in which glass fibers are bonded with an organic binder, and may be referred to as a “glass sheet” hereinafter. The compressed body is obtained by compressing this glass sheet in the thickness direction. The number of glass sheets used for producing the compressed body may be one, or a plurality of glass sheets may be stacked in the thickness direction.

In the slurry preparation step, the swelling agent, the glass fiber and the organic binder are dispersed in a predetermined dispersion medium. The slurry can be prepared by, for example, a mixer, a ball mill, a pulper or the like. Water can be used as the dispersion medium. The content of each raw material component in the slurry can be adjusted so that the content of each raw material component in the obtained lead storage battery separator falls within the above range.

The slurry may include a surfactant. When the slurry contains the surfactant, the raw material components are easily dispersed when the lead storage battery separator is manufactured. The surfactant may be decomposed in a subsequent heat treatment. The surfactant may be any of a silane coupling agent, a cationic surfactant, an anionic surfactant, a nonionic surfactant and the like. The content of the surfactant is preferably 0.01 to 5 mass% based on the total mass of the slurry.

In the paper making process, after making the paper (glass sheet) by making the slurry into paper using a general paper machine, in the compression making process, the paper is compressed in the thickness direction using a pressure machine. Thus, a compressed body (lead acid battery separator) can be produced. In order to obtain a desired compact, it is preferable to compress the paper product at 1 to 30 MPa for 1 to 5 minutes. As the paper product (glass sheet) used for producing the compressed body, one sheet may be used alone, or a plurality of sheets may be stacked in the thickness direction and used.

The heat treatment step is not necessarily performed, but can be performed as necessary according to the material constitution of the separator. By heat-treating the compressed body at a temperature equal to or higher than the softening point of the resin (organic binder) in the heat treatment step, the organic binder is softened and the glass fibers or the like can be reliably bound to each other. The treatment temperature is not necessarily limited because it depends on the softening point of the resin (organic binder), but is preferably 100 to 200°C. When the treatment temperature is 100° C. or higher, glass fibers and the like tend to be easily bound to each other. When the processing temperature is 200° C. or lower, the manufacturing process can be simplified easily. The heat treatment step may be performed while appropriately applying pressure, depending on the constituent material of the lead storage battery separator.

The lead storage battery according to the present embodiment can be used as a control valve type lead storage battery. The lead storage battery according to the present embodiment can be used in an electric vehicle. Examples of the electric vehicle include micro hybrid vehicles such as an ISS vehicle (idling start-stop system vehicle) and a power generation control vehicle. The electric vehicle according to the present embodiment includes the lead storage battery according to the present embodiment.

An electrode (for example, an electrode plate) of a lead storage battery has a current collector and an active material filling portion, and the active material filling portion is formed by filling the current collector with the active material. The positive electrode (for example, the positive electrode plate) has a positive electrode current collector and a positive electrode active material filling portion, and the positive electrode active material is filled with the positive electrode active material to form the positive electrode active material filling portion. .. The negative electrode (for example, the negative electrode plate) has a negative electrode current collector and a negative electrode active material filling portion, and the negative electrode active material is filled with the negative electrode active material to form the negative electrode active material filling portion. .. In the present specification, the positive electrode after the chemical conversion and the negative electrode current collector are removed is referred to as a “positive electrode active material”, and the negative electrode after the chemical conversion is removed and the negative electrode current collector is removed is referred to as the “negative electrode active material”.

The positive electrode active material may include β-PbO ₂ as a Pb component. The positive electrode active material may include alpha-PbO _2, it may not include the alpha-PbO _2. The positive electrode active material may contain a Pb component other than PbO ₂ (for example, PbSO ₄ ) and an additive described later, if necessary.

The positive electrode active material is obtained by obtaining an unformed positive electrode active material by aging and drying a paste positive electrode active material (positive electrode active material paste) containing a raw material of the positive electrode active material, and then forming the unformed positive electrode active material. Can be obtained at For the positive electrode, the unformed positive electrode active material is obtained by aging and drying the pasty positive electrode active material filled in the positive electrode current collector (casting grid body, expanded lattice body, etc.). It can be obtained by forming. The unformed positive electrode active material may contain tribasic lead sulfate as a main component. Examples of the raw material of the positive electrode active material include lead powder and lead tin (Pb ₃ O ₄ ).

The positive electrode current collector serves as a conductive path for a current from the positive electrode active material and holds the positive electrode active material. The positive electrode current collector has, for example, a lattice shape. Examples of the composition of the positive electrode current collector include lead alloys such as lead-calcium-tin alloys and lead-antimony-arsenic alloys. Selenium, silver, bismuth and the like may be added to the positive electrode current collector depending on the application. A positive electrode current collector can be obtained by forming these lead alloys in a lattice shape by a gravity casting method, an expanding method, a punching method or the like.

Examples of additives that can be included in the positive electrode active material include carbon materials (excluding carbon fibers) and reinforcing short fibers. Examples of the carbon material include carbon black and graphite. Examples of carbon black include furnace black, channel black, acetylene black, thermal black and Ketjen black. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers, and carbon fibers.

The negative electrode active material may include Pb as a Pb component. The negative electrode active material may contain a Pb component other than Pb (for example, PbSO ₄ ) and an additive described later, if necessary. The negative electrode active material may include porous spongy lead.

The negative electrode active material is obtained by obtaining an unformed negative electrode active material by aging and drying a pasty negative electrode active material (negative electrode active material paste) containing a raw material of the negative electrode active material, and then forming the unformed negative electrode active material. Can be obtained at For the negative electrode, the unformed negative electrode active material is obtained by aging and drying the pasty negative electrode active material filled in the negative electrode current collector (casting grid body, expanded lattice body, etc.). It can be obtained by forming. The unformed negative electrode active material may contain tribasic lead sulfate as a main component. Examples of the raw material for the negative electrode active material include lead powder.

The negative electrode current collector serves as a conductive path for a current from the negative electrode active material and holds the negative electrode active material. The negative electrode current collector may be the same as or different from the positive electrode current collector described above.

Examples of the additive that can be contained in the negative electrode active material include a resin having a sulfo group and/or a sulfonate group, barium sulfate, a carbon material (excluding carbon fiber), and a reinforcing short fiber. Examples of the resin having a sulfo group and/or a sulfonate group include, for example, lignin sulfonic acid, lignin sulfonate, and a condensate of phenols, aminoaryl sulfonic acid, and formaldehyde (for example, bisphenol, aminobenzene sulfonic acid, and Condensation product with formaldehyde). Examples of the carbon material include carbon black and graphite. Examples of carbon black include furnace black, channel black, acetylene black, thermal black and Ketjen black. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers, and carbon fibers.

The pasty positive electrode active material and/or the pasty negative electrode active material may contain a solvent and/or sulfuric acid. Examples of the solvent include water (for example, ion-exchanged water) and an organic solvent.

The method for manufacturing a lead storage battery according to the present embodiment includes a contact step of bringing sulfuric acid into contact with a separator that is laminated on an electrode and that contains a swelling agent (the separator of the above-described first aspect). In the contacting step, a swollen body containing the swelling agent and sulfuric acid (the separator of the second aspect described above) can be obtained.

The specific gravity of sulfuric acid in the contacting step is preferably within the following range. The specific gravity of sulfuric acid is preferably 1.25 or more, more preferably 1.28 or more, and even more preferably 1.3 or more, from the viewpoint of easily improving the adhesion between the electrode and the separator because the separator is likely to swell. The specific gravity of sulfuric acid is preferably 1.35 or less, more preferably 1.32 or less, and further preferably 1.31 or less, from the viewpoint of easily improving the adhesion between the electrode and the separator. From these viewpoints, the specific gravity of sulfuric acid is preferably 1.25 to 1.35.

The method of manufacturing the lead storage battery according to the present embodiment may include an electrode manufacturing step of obtaining an electrode before the contacting step. In the electrode manufacturing process, electrodes (positive electrode and negative electrode) including the above-described current collector and active material filled portion are obtained. The positive electrode and the negative electrode can be produced using, for example, the above-mentioned paste-like positive electrode active material and paste-like negative electrode active material.

The lead-acid battery manufacturing method according to the present embodiment may include a stacking step of stacking the electrode and the separator to obtain a stacked body between the electrode manufacturing step and the contacting step. The method for manufacturing a lead storage battery according to the present embodiment may include an assembly step of assembling a component member including a laminated body of electrodes and a separator to obtain a lead storage battery. The contacting step may be performed either before or after the assembling step.

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

<Production of separator>
(Example 1)
After adding 210 g of glass fibers A (water content: 5% by mass, manufactured by Lauscha, trade name: C-08-R) having a number average fiber diameter of 0.8 μm to 20 kg, a surfactant (dispersant Manufactured by Meisei Chemical Industry Co., Ltd., trade name: PASCOR HA-52, "PASCOR" is a registered trademark) 20 g was added to obtain a mixed solution A. After this mixed solution A was put into a 20 L pulper (manufactured by Kumagai Riki Kogyo Co., Ltd.), the mixed solution A was stirred for 10 minutes. For glass fiber B having a number average fiber diameter of 4.1 μm, a mixed solution (mixed solution B) was prepared by the same procedure and then stirred. After stirring, 4.5 kg was taken from the mixed solution A containing the glass fibers A, 0.5 kg was taken from the mixed solution B containing the glass fibers B, and then these mixed solutions A and B were mixed. A mixed solution C was obtained. That is, this mixed liquid C contained 90% by mass of glass fibers having a number average fiber diameter of 0.8 μm and 10% by mass of glass fibers having a number average fiber diameter of 4.1 μm, based on the total mass of the glass fibers. ..

After adding 4% by mass of aluminum sulfate (swelling agent, manufactured by Nippon Light Metal Co., Ltd.) to the mixed solution C, the mixture was stirred with a stirrer for 10 minutes. Then, a polypropylene emulsion (trade name: TC-4010, water dispersion obtained by amine-neutralizing a propylene-acrylic acid copolymer, manufactured by Unitika Ltd.) as an organic binder is used as a resin component with respect to the total mass of the glass fibers. Was added to the mixed solution C so that the content of the mixture was 9% by mass, and the mixture was stirred for 2 minutes to prepare a slurry A.

Slurry A (540 g) was poured into a φ160 mm round sheet machine (manufactured by Kumagai Riki Kogyo Co., Ltd.) equipped with an 80-mesh wire net while pouring water. Water was injected until the amount of water in the sheet machine became about 80% (7 L), and then the mixture was stirred several times with a stirring rod. Then, water was drained and paper was made to obtain a glass sheet.

This glass sheet was pressed at 410 kPa for 5 minutes with a press (made by Kumagai Riki Kogyo Co., Ltd.) and then dehydrated. After dehydration, it was heated and dried with a rotary dryer (Kumagaya Riki Kogyo Co., Ltd.) for 4 minutes at 120° C., and further sufficiently dried in a constant temperature bath at 105° C. to obtain a separator.

Using a Shopper type thickness meter (manufactured by Yasuda Seiki Co., Ltd.), the thickness was measured at 6 points under pressure of 20 kgf/cm ² (1.96 MPa), and the average value was obtained as the thickness of the separator. The thickness of the separator was 1.7 mm.

(Comparative Example 1)
A separator (thickness: 1.7 mm) was obtained in the same manner as in Example 1 except that aluminum sulfate was removed.

<Swelling test>
A 20 mm×20 mm×1.7 mm thick separator was immersed in sulfuric acid (aqueous solution of sulfuric acid, specific gravity 1.31) and water for 2 minutes and then taken out. Then, the separator was suspended for 2 minutes to remove excess water by its own weight. Then, the presence or absence of swelling of the separator was visually confirmed.

The state (photograph) of the separator after the test is shown in FIG. (A) in FIG. 1 shows the result of immersing the separator of Comparative Example 1 in sulfuric acid, (b) shows the result of immersing the separator of Example 1 in sulfuric acid, and (c) shows Comparative Example 1 The result of immersing the separator of Example 1 in water is shown, and (d) shows the result of immersing the separator of Example 1 in water. Of (a) to (d), swelling of the separator is confirmed only in the case of (b) (when the separator of Example 1 is immersed in sulfuric acid).

Claims (5)

Contains a swelling agent,
A lead-acid battery separator that can swell when contacted with sulfuric acid. A lead storage battery separator, which is a swelling body containing a swelling agent and sulfuric acid. An electrode and the separator for a lead storage battery according to claim 1 or 2,
A lead acid battery, wherein the lead acid battery separator is laminated on the electrode. A method of manufacturing a lead storage battery, comprising a step of bringing sulfuric acid into contact with a separator containing a swelling agent while being laminated on an electrode. A method for improving adhesion, which comprises using a swelling agent to improve the adhesion between a lead storage battery electrode and a separator.