JP2019216059A - Porous membrane, battery member, and zinc battery - Google Patents

Abstract

To provide a porous membrane and a battery member which enable production of a zinc battery with excellent life performance.SOLUTION: A porous membrane arranged between a positive electrode and a negative electrode in a zinc battery contains a calcium component. Here, the calcium component may contain calcium hydroxide. The porous membrane may further contain an indium component. The porous membrane has a porous substrate, and the calcium component may be supported on the porous substrate. The invention also relates to a battery member which has a collector, an electrode material, and the porous membrane in this order.SELECTED DRAWING: None

Description

  The present invention relates to a porous membrane, a battery member, and a zinc battery.

  As a zinc battery using a zinc negative electrode, a nickel zinc battery, an air zinc battery, a silver zinc battery and the like are known. For example, a nickel-zinc battery is a water-based battery using an aqueous electrolyte such as an aqueous solution of potassium hydroxide, and thus has high safety and a high electromotive force as a water-based battery due to the combination of a zinc electrode and a nickel electrode. It is known to have. Furthermore, nickel-zinc batteries can be used in industrial applications (for example, applications such as backup power supplies) and automotive applications (for example, applications such as hybrid vehicles) because of their low cost in addition to excellent input / output performance. Sex is being considered.

  A nickel zinc battery includes a positive electrode and a negative electrode that face each other with a porous film interposed therebetween. As a porous membrane used for a nickel zinc battery, a microporous film separator having a nickel layer on its surface is known (for example, see Patent Document 1 below).

JP-A-5-343096

  By the way, zinc batteries are required to have excellent life performance.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a porous membrane and a battery member capable of obtaining a zinc battery having excellent life performance. Another object of the present invention is to provide a zinc battery having excellent life performance.

  The present invention provides, as a first aspect, a porous membrane disposed between a positive electrode and a negative electrode of a zinc battery, the porous membrane containing a calcium component. According to such a porous membrane, a zinc battery having excellent life performance can be obtained.

  In a first embodiment, the calcium component preferably comprises calcium hydroxide.

  In the first embodiment, the porous membrane may further contain an indium component. According to such a porous membrane, it is possible to obtain a zinc battery having excellent life performance and suppressing self-discharge.

  In the first embodiment, the porous membrane has a porous substrate, and the calcium component may be supported on the porous substrate. Even with such a porous membrane, a zinc battery having excellent life performance can be obtained.

  The present invention provides, as a second aspect, a battery member having a current collector, an electrode material, and the above-described porous film in this order. According to such a battery member, a zinc battery having excellent life performance can be obtained.

  The present invention provides, as a third aspect, a zinc battery including a positive electrode, a negative electrode, and the above-described porous film, wherein the porous film is disposed between the positive electrode and the negative electrode. According to such a zinc battery, excellent life performance can be obtained.

  According to the present invention, it is possible to provide a porous membrane and a battery member capable of obtaining a zinc battery having excellent life performance. Further, according to the present invention, a zinc battery having excellent life performance can be provided.

  In the present specification, a numerical range indicated by using “to” indicates a range including numerical values described before and after “to” as a minimum value and a maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or lower limit value of a numerical range of a certain step can be arbitrarily combined with the upper limit value or lower limit value of the numerical range of another step. 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 values shown in the examples. “A or B” only needs to include either A or B, and may include both. The materials exemplified in the present specification can be used singly or in combination of two or more unless otherwise specified. In the present specification, the content of each component in the composition, if there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, the total amount of the plurality of substances present in the composition Means Further, in this specification, the term “layer” includes, when observed in a plan view, a structure having a partly formed shape in addition to a structure having a partly formed whole surface. Further, in this specification, the term "step" is used not only for an independent step but also for the case where the intended action of the step is achieved even if it cannot be clearly distinguished from other steps. included.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

  Examples of the zinc battery (for example, a zinc secondary battery) according to the present embodiment include a nickel zinc battery, an air zinc battery, and a silver zinc battery. As a basic configuration of the zinc battery according to the present embodiment, a configuration similar to a conventional zinc battery can be used.

  The zinc battery according to the present embodiment includes a positive electrode, a negative electrode, and a porous film disposed between the positive electrode and the negative electrode. The zinc battery according to this embodiment may include a battery member (battery member for zinc battery) having an electrode (a positive electrode or a negative electrode; an electrode for a zinc battery) and a porous film. The battery member according to the present embodiment has a current collector, an electrode material, and a porous film in this order, and includes, for example, a current collector, an electrode material supported on the current collector, and a support And a porous film. The porous membrane according to the present embodiment is a porous membrane disposed between a positive electrode and a negative electrode of a zinc battery, and contains a calcium component.

  According to the present embodiment, excellent life performance can be obtained in the zinc battery. The reason why such an effect is obtained is not clear, but the present inventors speculate as follows. However, the cause is not limited to the following contents.

In a zinc battery, zinc hydroxide (Zn (OH) ₂ ) is generated at the negative electrode by a discharge reaction. Zinc hydroxide is soluble in the electrolytic solution, and when zinc hydroxide is dissolved in the electrolytic solution, tetrahydroxyzincate ions ([Zn (OH) ₄ ] ²⁻ ) diffuse into the electrolytic solution. When the tetrahydroxyzincate ion is reduced to zinc by the charging reaction, the generation of zinc proceeds unevenly on the negative electrode. As a result, the morphological change of the negative electrode progresses and the distribution of the charging current becomes non-uniform, so that zinc is locally deposited on the negative electrode, and dendrite (dendritic deposition) occurs. When the dendrite penetrates the porous membrane and reaches the positive electrode, a short circuit occurs and the life performance deteriorates.
In contrast, in the present embodiment, the porous membrane contains a calcium component. The calcium component reacts with tetrahydroxy zincate ions in the negative electrode or on the negative electrode surface to form calcium tetrahydroxy zincate (CaZn (OH) ₄ ). Since calcium tetrahydroxyzincate is hardly dissolved in the electrolytic solution, diffusion of tetrahydroxyzincate ions into the electrolytic solution is suppressed. This makes it difficult for zinc to deposit on the negative electrode, and suppresses the generation of dendrites. As described above, in this embodiment, excellent life performance can be obtained.

  Hereinafter, a nickel zinc battery will be described as an example of the zinc battery according to the present embodiment.

  The zinc battery according to the present embodiment includes, for example, a battery case, an electrolytic solution, and an electrode group (for example, an electrode group). The electrolyte and the electrode group are housed in a battery case. The zinc battery according to the present embodiment may be either before or after chemical formation.

  The electrolytic solution contains, for example, a solvent and an electrolyte. Examples of the solvent include water (for example, ion-exchanged water). Examples of the electrolyte include basic compounds and the like, and alkali metal hydroxides such as potassium hydroxide (KOH), sodium hydroxide (NaOH), and lithium hydroxide (LiOH). The zinc battery according to the present embodiment can be used as an alkaline zinc battery using an alkaline electrolyte. The electrolytic solution may contain components other than the solvent and the electrolyte. For example, potassium phosphate, potassium fluoride, potassium carbonate, sodium phosphate, sodium fluoride, sodium hydroxide, lithium hydroxide, zinc oxide, oxide It may contain antimony, titanium dioxide, a nonionic surfactant, an anionic surfactant and the like.

  The electrode group includes, for example, a separator, and a positive electrode (a positive electrode plate or the like) and a negative electrode (a negative electrode plate or the like) opposed to each other with the separator interposed therebetween. The positive electrode has, for example, a positive electrode current collector and a positive electrode material supported by the positive electrode current collector. The negative electrode has, for example, a negative electrode current collector and a negative electrode material supported by the negative electrode current collector. The positive electrode and the negative electrode may be either before or after chemical formation. In the electrode group, the positive electrodes and the negative electrodes are connected by, for example, straps.

  The separator may be a single layer or a plurality of layers, and has at least the porous membrane according to the present embodiment. The porous film may be disposed between the positive electrode and the negative electrode, may be in contact with at least one of the positive electrode and the negative electrode, or may not be in contact with at least one of the positive electrode and the negative electrode.

  The porous film is preferably in contact with at least the negative electrode from the viewpoint of easily obtaining excellent life performance. For example, one surface of the porous film is in contact with the positive electrode, and the other surface of the porous film is in contact with the negative electrode. The porous membrane may be arranged on both surfaces of the positive electrode or the negative electrode, respectively. The porous film is in contact with, for example, at least one of the positive electrode material of the positive electrode and the negative electrode material of the negative electrode. When the porous film is in contact with the positive electrode material, the electrode group includes a battery member having a current collector (a positive electrode current collector), a positive electrode material, and a porous film in this order. When the porous film is in contact with the negative electrode material, the electrode group includes a battery member having a current collector (a negative electrode current collector), a negative electrode material, and a porous film in this order.

  When the porous film is not in contact with the positive electrode or the negative electrode, a porous film containing no calcium component can be disposed between the positive electrode or the negative electrode and the porous film. The separator may be, for example, an embodiment having the porous membrane according to the present embodiment between two porous membranes containing no calcium component.

  The porous membrane according to the present embodiment is a porous membrane having porosity, and may be a membrane containing a calcium component. The porous membrane may have, for example, any of a mode composed of a calcium component (for example, a mode composed of calcium alone or a calcium compound) and a mode composed of a calcium component and other components.

  The calcium component is a component containing at least a calcium atom, and is at least one selected from the group consisting of simple calcium and a calcium compound. Examples of the calcium compound include calcium hydroxide, calcium oxide, calcium sulfate and the like. The calcium compound preferably contains calcium hydroxide from the viewpoint of easily obtaining excellent life performance.

  The content of the calcium component in the porous membrane is preferably in the following range based on the total amount of the porous membrane (when the porous membrane has a porous substrate described below, excluding the porous substrate. The same applies hereinafter). The content of the calcium component is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, particularly preferably 20% by mass or more, from the viewpoint of easily obtaining excellent life performance, and 40% by mass or more. % Or more is very preferable, 60% by mass or more is very preferable, and 70% by mass or more is still more preferable. The content of the calcium component is preferably 99% by mass or less, more preferably 97% by mass or less, still more preferably 95% by mass or less, particularly preferably 90% by mass or less, from the viewpoint of easily obtaining excellent life performance, and 85% by mass or less. % Or less, and still more preferably 80% by mass or less.

  The porous membrane may further contain other metal components other than the calcium component. Examples of the metal component include an indium component and a bismuth component. The porous film preferably contains an indium component from the viewpoint of suppressing self-discharge. The indium component is a component containing at least an indium atom, and is at least one selected from the group consisting of indium alone and an indium compound.

  The reason why the self-discharge can be suppressed when the porous film contains the indium component is not clear, but the present inventors speculate as follows. However, the cause is not limited to the following contents.

  In a zinc battery, zinc deposition occurs locally on the negative electrode, as described above. The deposited zinc promotes the generation of hydrogen gas in the electrolyte (decomposition of the electrolyte), and as a result, promotes self-discharge due to the decrease of the electrolyte (self-discharge occurs remarkably especially in a high-temperature environment). obtain). On the other hand, when the porous film contains an indium component, the indium component can form an alloy with the precipitated zinc, thereby suppressing self-discharge caused by zinc (particularly, self-discharge in a high-temperature environment (for example, 35 ° C. or higher)). Discharge can be suppressed). By suppressing self-discharge, it is easy to obtain excellent life performance.

  Examples of the indium compound include indium sulfate, indium nitrate, indium oxide, and the like. The indium compound preferably contains indium sulfate from the viewpoint of easily suppressing self-discharge.

  When the porous film contains an indium component, the content of the indium component is preferably in the following range based on the total amount of the porous film. The content of the indium component is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more, from the viewpoint of easily suppressing self-discharge. The content of the indium component is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less, from the viewpoint of easily obtaining excellent life performance.

  In the porous membrane, the ratio of the content of the calcium component to the content of the indium component (the content of the calcium component / the content of the indium component) is preferably in the following range in terms of mass ratio. The content of the calcium component / the content of the indium component is preferably 1 or more, more preferably more than 1, more preferably 5 or more, and particularly preferably 10 or more, from the viewpoint of easily suppressing self-discharge. The content of the calcium component / the content of the indium component is preferably 60 or less, more preferably 50 or less, still more preferably 40 or less, particularly preferably 30 or less, and most preferably 20 or less, from the viewpoint of easily obtaining excellent life performance. Preferably, 10 or less is very preferred.

  The porous membrane according to the present embodiment may contain a resin material. Examples of the resin material include hydrophilic or hydrophobic polymers. Fluorine-based polymers (eg, polytetrafluoroethylene (PTFE)), nonionic water-soluble polymers (eg, polyethylene oxide (PEOX)), acrylic acid-based polymers (For example, sodium polyacrylate (SPA)), polyamide-based polymer (for example, polyamide), olefin-based polymer (for example, polyolefin), nylon-based polymer (for example, nylon), and styrene-butadiene-based polymer (for example, styrene-butadiene rubber). The resin material can be used as a binder in the porous film.

  The content of the resin material may be in the following range based on the total amount of the porous membrane. The content of the resin material may be 1% by mass or more, 3% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more from the viewpoint of easily obtaining excellent life performance. The content of the resin material is 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, 60% by mass or less, 40% by mass or less, and 30% by mass from the viewpoint of easily obtaining excellent life performance. Hereinafter, it may be 25% by mass or less, or 20% by mass or less.

  The porous membrane may have a porous substrate. In this case, at least the calcium component may be supported on the porous substrate, and a component other than the calcium component (eg, a resin material) may be supported on the porous substrate.

  Examples of the material of the porous substrate include an organic material (such as a resin material) and an inorganic material. Examples of the resin material include a polyamide-based polymer (eg, polyamide), an olefin-based polymer (polyolefin), and a nylon-based polymer (eg, nylon). Examples of the inorganic material include oxides such as alumina, titania, and silicon dioxide; nitrides such as aluminum nitride and silicon nitride; and sulfates such as barium sulfate and calcium sulfate. The porous substrate may be a porous sheet, woven or nonwoven made of these materials.

  The porosity of the porous film is preferably 30% by volume or more, more preferably 40% by volume or more, and still more preferably 50% by volume or more, from the viewpoint of easily obtaining excellent life performance. The porosity of the porous film is preferably equal to or less than 80% by volume, more preferably equal to or less than 70% by volume, and still more preferably equal to or less than 60% by volume, from the viewpoint of easily obtaining excellent life performance. The porosity of the porous membrane can be measured by a mercury intrusion method using a pore distribution measuring device (manufactured by Micromeritics, trade name: AutoPore IV9510). The porosity of the porous membrane can be adjusted by the content of the components (calcium component, resin material, etc.) of the porous membrane.

  The average pore diameter of the porous membrane is preferably 0.1 μm or more, more preferably 0.5 μm or more, and still more preferably 1 μm or more. The average pore diameter of the porous membrane is preferably 10 μm or less, more preferably 7 μm or less, and still more preferably 5 μm or less, from the viewpoint that it is easy for the dendrite to penetrate through the porous membrane to reach the positive electrode and thereby obtain excellent life performance. From these viewpoints, the average pore diameter of the porous membrane is preferably from 0.1 to 10 μm. The average pore diameter of the porous membrane can be measured by a mercury porosimeter (for example, trade name: AutoPore IV9510, manufactured by Micromeritics). The average pore diameter of the porous membrane can be adjusted by the content of the constituent components (calcium component, resin material, etc.) of the porous membrane.

  The thickness of the porous film is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, particularly preferably 20 μm or more, particularly preferably 30 μm or more, and very preferably 40 μm or more from the viewpoint of easily obtaining excellent life performance. It is more preferably at least 50 μm, even more preferably at least 80 μm. The thickness of the porous membrane is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. From these viewpoints, the thickness of the porous film is preferably from 5 to 200 μm. As the thickness (film thickness) of the porous film, an average value of the thickness can be used. For example, the average value of the thickness of any 9 points of a porous film processed so that one side is 10 cm measured with a micrometer (for example, PMU150-25MX manufactured by Mitutoyo Corporation) is the thickness of the porous film. Can be used.

  The porous membrane may contain an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like from the viewpoint of making the membrane hydrophilic, and may include a sulfonation treatment, a fluorine gas treatment, and an acrylic surfactant. Surface treatment may be performed by acid graft polymerization treatment, corona discharge treatment, plasma treatment, or the like. By making it hydrophilic, it is easy to be compatible with the electrolyte solution and it is easy to obtain a sufficient current density.

  The positive electrode current collector forms a conductive path for current from the positive electrode material. The positive electrode current collector has, for example, a plate shape, a sheet shape, or the like. The positive electrode current collector may be a current collector having a three-dimensional network structure formed of a foamed metal, an expanded metal, a punched metal, a felt-like metal fiber material, or the like. The positive electrode current collector is made of a material having conductivity and alkali resistance. Examples of such a material include a material that is stable even at the reaction potential of the positive electrode (a material having an oxidation-reduction potential that is more noble than the reaction potential of the positive electrode, and a protective film such as an oxide film formed on a substrate surface in an aqueous alkaline solution). And the like, which stabilizes the material). In the positive electrode, the decomposition reaction of the electrolytic solution proceeds as a side reaction to generate oxygen gas, and a material having a high oxygen overvoltage is preferable in that the progress of such a side reaction can be suppressed. Specific examples of a material constituting the positive electrode current collector include platinum; nickel; and a metal material (copper, brass, steel, or the like) plated with metal such as nickel.

  The positive electrode material may be layered (positive electrode material layer). For example, a positive electrode material layer may be formed on the positive electrode current collector, and when the positive electrode current collector has a three-dimensional network structure, the positive electrode material is filled between meshes of the positive electrode current collector to form a positive electrode. A material layer may be formed.

  The positive electrode material contains a positive electrode active material. Examples of the positive electrode active material include nickel oxyhydroxide (NiOOH) and nickel hydroxide. The positive electrode material contains, for example, nickel oxyhydroxide in a fully charged state, and contains nickel hydroxide in a discharged state. The content of the positive electrode active material may be, for example, 50 to 95% by mass based on the total mass of the positive electrode material.

  The positive electrode material can contain additives other than the positive electrode active material. Examples of the additive include a binder, a conductive agent, and an expansion inhibitor. Examples of the binder include hydrophilic or hydrophobic polymers. Carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC), hydroxypropylmethylcellulose (HPMC), sodium polyacrylate (SPA), fluoropolymer (poly) And tetrafluoroethylene (PTFE). The content of the binder may be, for example, 0.01 to 5 parts by mass with respect to 100 parts by mass of the positive electrode active material. Examples of the conductive agent include a cobalt compound (metal cobalt, cobalt oxide, cobalt hydroxide, and the like). The content of the conductive agent may be, for example, 1 to 20 parts by mass with respect to 100 parts by mass of the positive electrode active material. Examples of the expansion inhibitor include zinc oxide. The content of the expansion inhibitor may be, for example, 0.01 to 5 parts by mass with respect to 100 parts by mass of the positive electrode active material.

  The negative electrode current collector forms a conductive path for current from the negative electrode material. The negative electrode current collector has, for example, a flat plate shape, a sheet shape, or the like. The negative electrode current collector may be a current collector having a three-dimensional network structure formed of a foamed metal, an expanded metal, a punching metal, a felt-like metal fiber material, or the like. The negative electrode current collector is made of a material having conductivity and alkali resistance. As such a material, for example, a material which is stable even at the reaction potential of the negative electrode (a material having a redox potential which is more noble than the reaction potential of the negative electrode, and a protective film such as an oxide film formed on a substrate surface in an alkaline aqueous solution) And the like, which stabilizes the material). In the negative electrode, the decomposition reaction of the electrolytic solution proceeds as a side reaction to generate hydrogen gas, and a material having a high hydrogen overvoltage is preferable in that the progress of such a side reaction can be suppressed. Specific examples of the material constituting the negative electrode current collector include metal materials (copper, brass, steel, nickel, and the like) plated with metal such as zinc; lead; tin; and tin.

  The negative electrode material may be layered (negative electrode material layer). For example, a negative electrode material layer may be formed on the negative electrode current collector, and when the negative electrode current collector has a three-dimensional network structure, the negative electrode material is filled between the meshes of the negative electrode current collector to form a negative electrode. A material layer may be formed.

  The negative electrode material contains a negative electrode active material containing zinc. Examples of the negative electrode active material include zinc metal, zinc oxide, and zinc hydroxide. The negative electrode material contains, for example, metallic zinc in a fully charged state and zinc oxide and zinc hydroxide in a discharged state.

  The content of the negative electrode active material is preferably in the following range based on the total mass of the negative electrode material. The content of the negative electrode active material is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 75% by mass or more, from the viewpoint of easily achieving both excellent life performance and discharge performance. The content of the negative electrode active material is preferably equal to or less than 95% by mass, more preferably equal to or less than 90% by mass, and still more preferably equal to or less than 85% by mass, from the viewpoint of easily achieving both excellent life performance and discharge performance. From these viewpoints, the content of the negative electrode active material is preferably from 50 to 95% by mass.

  The negative electrode material can contain additives other than the negative electrode active material. Examples of the additive include a binder and a conductive agent. Examples of the binder include polytetrafluoroethylene, hydroxyethyl cellulose, polyethylene oxide, polyethylene, and polypropylene. The content of the binder may be, for example, 0.5 to 10 parts by mass with respect to 100 parts by mass of the negative electrode active material. Examples of the conductive agent include an indium compound (such as indium oxide). The content of the conductive agent may be, for example, 1 to 20 parts by mass with respect to 100 parts by mass of the negative electrode active material.

  Next, a method for manufacturing the zinc battery (for example, a nickel zinc battery) according to the present embodiment will be described. The method for manufacturing a zinc battery includes, for example, a component manufacturing process for obtaining a component of the zinc battery, and an assembly process for assembling the components to obtain a zinc battery. In the component member manufacturing process, at least an electrode (a positive electrode and a negative electrode) and a porous film are obtained.

  The electrode is obtained, for example, by adding a solvent (for example, water) to the raw material of the electrode material (the positive electrode material and the negative electrode material) and kneading the same to obtain an electrode material paste (a paste-like electrode material). To form an electrode material layer.

  Examples of the raw material of the positive electrode material include a raw material of the positive electrode active material (for example, nickel hydroxide), an additive (for example, the binder), and the like. Examples of the raw material of the negative electrode material include raw materials of the negative electrode active material (for example, metallic zinc, zinc oxide, and zinc hydroxide), and additives (for example, the binder).

  As a method of forming the electrode material layer, for example, a method of obtaining an electrode material layer by applying or filling an electrode material paste on a current collector and then drying the paste is used. The density of the electrode material layer may be increased by pressing or the like as necessary.

  The porous membrane can be obtained, for example, by volatilizing the dispersion medium after a slurry obtained by dispersing a calcium component and other components (for example, a resin material) in a dispersion medium is brought into contact with an electrode or a porous substrate. it can. For example, the slurry can be brought into contact with the electrode or the porous substrate by applying or impregnating the slurry on the electrode or the porous substrate.

  In the assembling process, the positive electrode and the negative electrode obtained in the component member manufacturing process are alternately stacked via a separator. At least one of the separators has the porous membrane according to the present embodiment. Thereafter, the positive electrodes and the negative electrodes are connected to each other with a strap to form an electrode group.

  Subsequently, after injecting the electrolytic solution into the battery case of the unformed zinc battery, it is left for a certain time. Next, a zinc battery (nickel-zinc battery) is obtained by forming the battery by charging it under predetermined conditions. The formation conditions can be adjusted according to the properties of the electrode active materials (the positive electrode active material and the negative electrode active material).

  The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in the above-described embodiment, an example of a nickel zinc battery (for example, a nickel zinc secondary battery) in which the positive electrode is a nickel electrode has been described. However, a zinc battery is an air zinc battery (for example, air zinc secondary battery) in which the positive electrode is an air electrode. Battery) or a silver-zinc battery whose positive electrode is a silver oxide electrode (for example, a silver-zinc secondary battery).

  As the air electrode of the zinc-air battery, a known air electrode used for a zinc-air battery can be used. The air electrode includes, for example, an air electrode catalyst, an electron conductive material, and the like. As the cathode catalyst, an cathode catalyst that also functions as an electron conductive material can be used.

  As the cathode catalyst, one that functions as a cathode in an air zinc battery can be used, and various cathode catalysts that can use oxygen as a cathode active material can be used. Examples of the air electrode catalyst include a carbon-based material having a redox catalyst function (eg, graphite), a metal material having a redox catalyst function (eg, platinum and nickel), and an inorganic oxide material having a redox catalyst function (a perovskite oxide). Manganese dioxide, nickel oxide, cobalt oxide, spinel oxide, etc.). The shape of the air electrode catalyst is not particularly limited, but may be, for example, particulate. The content of the air electrode catalyst in the air electrode may be 5 to 70% by volume, 5 to 60% by volume, or 5 to 50% by volume based on the total amount of the air electrode. Is also good.

  As the electron conductive material, a material having conductivity and capable of conducting electrons between the air electrode catalyst and the separator can be used. Examples of the electron conductive material include carbon blacks such as Ketjen black, acetylene black, channel black, furnace black, lamp black, and thermal black; graphites such as natural graphite such as flake graphite, artificial graphite, and expanded graphite; Conductive fibers such as carbon fiber and metal fiber; metal powders such as copper, silver, nickel and aluminum; organic electronic conductive materials such as polyphenylene derivatives; and arbitrary mixtures thereof. The shape of the electron conductive material may be a particle shape or another shape. The electron conductive material is preferably used in a form that provides a continuous phase in the thickness direction at the cathode. For example, the electron conductive material may be a porous material. Further, the electron conductive material may be in the form of a mixture or a composite with the air electrode catalyst, or as described above, may be an air electrode catalyst that also functions as an electron conductive material. The content of the electron conductive material in the air electrode may be 10 to 80% by volume, 15 to 80% by volume, or 20 to 80% by volume based on the total amount of the air electrode. You may.

  As a silver oxide electrode of a silver zinc battery, a known silver oxide electrode used for a silver zinc battery can be used. The silver oxide electrode contains, for example, silver (I) oxide.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.

<Preparation of nickel zinc battery>
(Example 1)
[Preparation of nickel electrode]
A sponge-like nickel metal porous body having a porosity of 96% and a thickness of 1.4 mm was pressure-formed by a roll press to a thickness of 0.8 mm. Next, 88 parts by mass of cobalt-coated nickel hydroxide powder having an average particle diameter of 20 μm and additives (8 parts by mass of cobalt powder, 2 parts by mass of cobalt oxide, 2 parts by mass of zinc oxide, and a 2% by mass aqueous solution of carboxymethyl cellulose 30%) Parts by mass) to obtain a positive electrode material paste. After filling this positive electrode material paste into the above-mentioned porous nickel metal body, it was dried at 80 ° C. for 60 minutes. Then, a nickel electrode was produced by press-molding to a thickness (total thickness) of 0.41 mm by a roll press.

[Production of zinc electrode]
PTFE dispersion (Mitsui / Dupont Fluoro) containing 60 parts by mass of PTFE in a mixed powder obtained by mixing 82 parts by mass of zinc oxide powder, 10 parts by mass of zinc powder, and 5 parts by mass of an additive (indium oxide) After adding 5 parts by mass of Teflon (registered trademark) 31-JR (trade name, manufactured by Chemical Co., Ltd.) and 10 parts by mass of water, the mixture was kneaded in a mortar for 15 minutes while applying shear stress to obtain a kneaded product. Next, after adding 40 parts by mass of water, the mixture was kneaded for 15 minutes to obtain a negative electrode material paste. The negative electrode material paste was rolled to 1.0 mm with a roller to form a sheet, and then two sheets having a predetermined size were cut out. After arranging two sheets (negative electrode material) on both sides of a current collector (a punching metal made of tin-plated copper having a thickness of 0.1 mm), the sheet is subjected to pressure molding and drying to form a zinc electrode having a thickness of 0.4 mm. Produced.

[Preparation of porous membrane]
A slurry was prepared by dispersing 80 parts by mass of calcium hydroxide (Ca (OH) ₂ ) and 20 parts by mass of a resin material (PTFE) in a dispersion medium (water). A nonwoven fabric (VL100 (manufactured by Nippon Advanced Paper Industry Co., Ltd.)) was prepared as a porous substrate. The nonwoven fabric was impregnated into the slurry and then dried, whereby the components contained in the slurry were carried on the nonwoven fabric to obtain a porous membrane. The porosity of the porous membrane was 55% by volume, the average pore diameter was 3 μm, and the thickness was 100 μm.

[Assembly of nickel zinc battery]
After alternately laminating two nickel electrodes and three zinc electrodes via the produced porous membrane, electrode plates having the same polarity were connected by spot welding to prepare an electrode group. This electrode group was placed in a battery case to obtain an unformed nickel-zinc battery. An aqueous solution of 30% by weight of potassium hydroxide containing 1% by weight of lithium hydroxide was injected into an unformed nickel-zinc battery as an electrolyte. Thereafter, the battery was charged at a current of 30 mA for 11 hours in an environment of 25 ° C., and then discharged to 1.0 V at a current of 150 mA. Subsequently, the battery was charged at a current value of 60 mA for 5 hours, and then discharged to 1.3 V at a current value of 150 mA. There was a one hour pause between charging and discharging. Thus, a nickel-zinc battery having a designed capacity of 300 mAh was manufactured.

(Example 2)
A nickel zinc battery was produced in the same manner as in Example 1, except that a slurry was prepared by further adding 10 parts by mass of indium sulfate (In ₂ (SO ₄ ) ₃ ) when producing the porous membrane.

Example 3
A nickel electrode and a zinc electrode were manufactured in the same manner as in Example 1. Next, the slurry prepared in the same manner as in Example 1 was applied to the zinc electrode, and then the dispersion medium was volatilized, thereby forming a porous film on the two negative electrodes of the zinc electrode. After alternately laminating two nickel electrodes and three zinc electrodes on which a porous film is formed via a separator (made of polypropylene, 25 μm in thickness), a nickel-zinc battery is produced in the same manner as in Example 1. did.

(Example 4)
A nickel zinc battery was produced in the same manner as in Example 3, except that a slurry was prepared by further adding 10 parts by mass of indium sulfate (In ₂ (SO ₄ ) ₃ ).

(Comparative Example 1)
Example 1 except that a porous membrane containing a calcium component was not used, and two nickel electrodes and three zinc electrodes were alternately laminated via a separator (made of polypropylene, 25 μm in thickness) during production of an electrode group. A nickel-zinc battery was produced in the same manner as described above.

<Battery performance evaluation>
Using the nickel zinc battery, cycle life performance and self-discharge were evaluated. The results are shown in Table 1.

(Cycle life performance evaluation)
In a 25 ° C. environment, the nickel-zinc battery is charged by charging at a constant voltage of 1.9 V at a current value of 300 mA (1 C) and then charging at a constant voltage until the current value reaches 15 mA (0.05 C). Further, a test in which discharging of the nickel-zinc battery was performed at a constant current of 150 mA (0.5 C) until the battery voltage reached 1.1 V as one cycle was performed at a maximum of 100 cycles. The discharge capacity was measured at the first and 100th cycles of charge and discharge. Then, the ratio of the discharge capacity at the 100th cycle to the discharge capacity at the first cycle was calculated as the capacity retention ratio. The higher the capacity retention ratio, the higher the life performance. The case where the capacity retention ratio was 90% or more was evaluated as “A”, and the case where the capacity maintenance ratio was less than 90% was evaluated as “B”.

  The “C” related to the current value relatively represents the magnitude of the current when the nominal capacity is discharged at a constant current from the fully charged state. The “C” means “discharge current value (A) / battery capacity (Ah)”. For example, a current that can discharge the nominal capacity in one hour is expressed as “1C”, and a current that can be discharged in two hours is expressed as “0.5 C”.

(Self-discharge evaluation)
The nickel zinc battery was left in an environment of 40 ° C. for 60 days, and the discharge capacity before and after the storage was compared. A case where the discharge capacity after leaving was 90% or more of the discharge capacity before leaving was evaluated as “A”, and a case where the discharging capacity after leaving was less than 90% of the discharge capacity before leaving was “B”. Was evaluated.

Claims (6)

A porous membrane disposed between a positive electrode and a negative electrode of a zinc battery,
A porous membrane containing a calcium component.   The porous membrane according to claim 1, wherein the calcium component includes calcium hydroxide.   The porous membrane according to claim 1, further comprising an indium component. Having a porous substrate,
The porous membrane according to any one of claims 1 to 3, wherein the calcium component is supported on the porous substrate.   A battery member comprising a current collector, an electrode material, and the porous membrane according to claim 1 in this order. A positive electrode, a negative electrode, and the porous membrane according to any one of claims 1 to 4, comprising:
A zinc battery, wherein the porous membrane is disposed between the positive electrode and the negative electrode.