JP6664195B2 - Zinc secondary battery - Google Patents

Description

  The present invention relates to a zinc secondary battery.

  Although zinc secondary batteries such as nickel zinc secondary batteries have been developed and studied for a long time, they have not yet been put to practical use. This is because zinc constituting the negative electrode generates dendritic crystals called dendrites at the time of charging, and this dendrite breaks through the separator and causes a short circuit with the positive electrode. Therefore, in a zinc secondary battery such as a nickel zinc secondary battery, a technique for preventing a short circuit due to zinc dendrite is strongly desired.

In order to address such problems or demands, batteries using a hydroxide ion conductive ceramic separator have been proposed. For example, Patent Literature 1 (International Publication No. 2013/118561) discloses that in a nickel zinc secondary battery, a separator made of a hydroxide ion conductive inorganic solid electrolyte is used as a positive electrode in order to prevent a short circuit caused by zinc dendrite. and it is is disclosed that provided between the negative electrode, the general formula as an inorganic solid electrolyte ^{_{body: M 2+ 1-x M 3+}} x (OH) 2 a n- x / n · mH 2 O ( ^{wherein, M 2+} is at least is at least one divalent cation, M ³⁺ is at least one or more trivalent cations, a ^n-is the n-valent anion, n represents an integer of 1 or more, x is 0 It is proposed to use a layered double hydroxide (LDH) having a basic composition of (.1 to 0.4). Further, Patent Document 2 (WO 2015/098610) discloses a layered double hydroxide-containing composite material including a porous substrate and a functional layer containing a layered double hydroxide. It describes that the functional layer does not have water permeability.

  On the other hand, in order to obtain a high voltage and a large current, a laminated battery formed by combining a plurality of unit cells is widely used. The stacked battery has a configuration in which a stacked body formed by connecting a plurality of cells in series or in parallel is housed in one battery container.

WO 2013/118561 WO 2015/098610

The present applicant has succeeded in developing a ceramic separator (inorganic solid electrolyte separator) which is highly densified so as to have hydroxide ion conductivity but not to have water permeability. In addition, the formation of such a ceramic separator on a porous substrate has also been successful. When a secondary battery such as a nickel zinc battery is formed using such a separator (or a separator with a porous substrate), a short circuit due to zinc dendrite can be prevented. In order to maximize this effect, it is desired that the hydroxide ion conductive ceramic separator reliably separates the inside of the battery container between the positive electrode side and the negative electrode side. However, when the inside of the battery container is reliably partitioned between the positive electrode side and the negative electrode side by the hydroxide ion conductive ceramic separator, there is a problem that the overcharge resistance may be reduced. That is, when overcharged in a zinc secondary battery such as a nickel zinc battery, oxygen (O ₂ ) may be generated at the positive electrode. However, the hydroxide ion conductive ceramics described above have a high degree of denseness such that only hydroxide ions are substantially passed therethrough, and thus do not allow O ₂ to pass through. For this reason, if O ₂ can be efficiently sent from the positive electrode chamber to the negative electrode chamber, thereby oxidizing Zn of the negative electrode with O ₂ and returning it to ZnO while securing high density of the separator, This is advantageous because overcharge resistance can be improved.

  The present inventors have recently proposed, in a zinc secondary battery provided with a separator structure including a hydroxide ion conductive separator, a positive electrode chamber, a negative electrode chamber, and a By providing a gas flow path structure that communicates gas with the upper space, a zinc secondary battery that can improve overcharge resistance while securing excellent separator characteristics effective in preventing short circuit due to zinc dendrite is provided. The knowledge that it can be provided was obtained. It has also been found that the zinc secondary battery can be provided in the form of a laminated battery having a simple structure that is easy to assemble.

  Therefore, an object of the present invention is to provide a zinc secondary battery having a separator structure including a hydroxide ion conductive separator, while ensuring excellent separator characteristics effective in preventing short circuit due to zinc dendrites, An object of the present invention is to provide a zinc secondary battery capable of improving charge resistance. It is another object of the present invention to provide a zinc-ion secondary battery in the form of a stacked battery having a simple structure that is easy to assemble.

According to one embodiment of the present invention, a closed container,
A positive electrode chamber and a negative electrode chamber, which are provided in a closed container and open or communicate with each other at the top,
A positive electrode housed in the positive electrode chamber;
A cathode electrolyte containing the alkali metal hydroxide aqueous solution, which is accommodated in the cathode chamber;
A negative electrode housed in the negative electrode chamber and containing zinc and / or zinc oxide;
A negative electrode electrolyte contained in the negative electrode chamber and containing an aqueous alkali metal hydroxide solution,
A separator structure including a separator provided to partition the positive electrode chamber and the negative electrode chamber, and having a hydroxide ion conductivity but having no water permeability,
A positive electrode gas flow path structure provided on the opposite side of the positive electrode to the separator in the positive electrode chamber and communicating gas between the positive electrode and an upper space of the positive electrode chamber;
A negative electrode gas flow path structure provided on the opposite side of the negative electrode to the separator in the negative electrode chamber, and gas-communicating between the negative electrode and an upper space of the negative electrode chamber;
A zinc secondary battery comprising:

1 is a schematic cross-sectional view of a zinc secondary battery according to one embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a zinc secondary battery according to another embodiment of the present invention. FIG. 4 is a schematic sectional view of a zinc secondary battery according to still another embodiment of the present invention. FIG. 4 is a schematic sectional view of a zinc secondary battery according to still another embodiment of the present invention. FIG. 4 is a schematic sectional view of a zinc secondary battery according to still another embodiment of the present invention. It is a schematic diagram which shows the gas flow path structure provided with the lattice-shaped uneven | corrugated shape. It is a schematic diagram which shows the gas flow path structure provided with the slit-shaped uneven | corrugated shape. FIG. 3 is a schematic diagram showing a gas flow path structure including a gap space functioning as a gas flow path provided along both right and left ends of an electrode. It is a schematic cross section showing one mode of a separator with a porous substrate. It is a schematic cross section which shows another aspect of the separator with a porous base material. It is a schematic diagram which shows a layered double hydroxide (LDH) plate-like particle. 3 is an SEM image of the surface of the porous alumina substrate manufactured in Example 1. 3 is an XRD profile obtained for a crystal phase of a sample in Example 1. 3 is an SEM image showing the surface microstructure of the film sample observed in Example 1. 3 is an SEM image of a microstructure of a polished cross section of the composite material sample observed in Example 1. FIG. 2 is an exploded perspective view of a denseness determination measurement system used in Example 1. FIG. 2 is a schematic cross-sectional view of a denseness determination measurement system used in Example 1. FIG. 2 is an exploded perspective view of a closed container for measurement used in a denseness determination test II of Example 1. FIG. 2 is a schematic cross-sectional view of a measurement system used in a denseness determination test II of Example 1. FIG. 9 is a top view schematically illustrating a positional relationship between components of a separator structure manufactured in Example 2. FIG. 4 is a process chart showing a procedure for producing a separator structure produced in Example 2. 4 is a photograph of a separator structure manufactured in Example 2. 4 is a photograph of a laminate before heat fusion bonding produced in Example 2. 4 is a photograph of a laminate after heat fusion bonding produced in Example 2. 4 is a photograph of the laminated nickel-zinc battery cartridge produced in Example 2. It is a conceptual diagram which shows an example of a He transmittance measurement system. FIG. 18B is a schematic cross-sectional view of a sample holder used in the measurement system shown in FIG. 18A and its peripheral configuration. It is a conceptual diagram which shows an example of a Zn transmission rate measuring apparatus. FIG. 19B is a schematic cross-sectional view of a sample holder used in the measurement device shown in FIG. 19A. 9 is a graph showing the relationship between the He transmittance and the Zn transmission ratio measured in Example 3.

Zinc secondary battery present invention relates to zinc secondary battery. In the present specification, a zinc secondary battery is a hydroxide ion conductive ceramic separator such as a nickel zinc secondary battery, a silver zinc secondary battery, a manganese zinc secondary battery, and various other alkaline zinc secondary batteries. Can be applied to various zinc secondary batteries. Particularly, a nickel zinc secondary battery is preferable. Therefore, in the following general description, the description may be made based on a nickel-zinc secondary battery which is a typical example, but the secondary battery to which the separator structure of the present invention can be applied is limited to a nickel-zinc secondary battery. However, the present invention can be applied to the above-mentioned various secondary batteries that can employ a hydroxide ion conductive ceramic separator. The battery to which the separator structure can be applied may be a unit battery having one pair of the positive electrode and the negative electrode, or a laminated battery having two or more unit batteries of the positive electrode and the negative electrode. You may. Further, the stacked battery may be a series stacked battery or a parallel stacked battery.

  FIG. 1 schematically shows an example of a zinc secondary battery according to the present invention. The zinc secondary battery 100 shown in FIG. 1 includes a positive electrode chamber 12 and a negative electrode chamber 14, a positive electrode 16, a positive electrode electrolyte (not shown), a negative electrode 18, a negative electrode electrolyte (not shown), and a separator. The structure 20, the cathode gas channel structure 22, and the anode gas channel structure 24 are provided in a closed container 102. As shown in FIG. 1, the zinc secondary battery preferably includes a plurality of at least one (preferably, both) of the positive electrode chamber 12 and the negative electrode chamber 14, and typically includes a stacked battery (or a stacked battery). (Assembled battery). However, the present invention is not limited to this, and may have a configuration of a unit cell having only one positive electrode chamber 12 and one negative electrode chamber 14. The positive electrode chamber 12 and the negative electrode chamber 14 are provided in a closed container 102, and are opened or communicated with each other at the top. The positive electrode chamber 12 contains a positive electrode 16 and a positive electrode electrolyte, and the positive electrode electrolyte contains an alkali metal hydroxide aqueous solution. The negative electrode chamber 14 contains a negative electrode 18 and a negative electrode electrolyte. The negative electrode 18 contains zinc and / or zinc oxide, and the negative electrode electrolyte contains an aqueous alkali metal hydroxide solution. The separator structure 20 includes a separator 28 having hydroxide ion conductivity but not having water permeability, and is provided so as to partition the positive electrode chamber 12 and the negative electrode chamber 14. Further, a positive electrode gas flow path structure 22 is provided in the positive electrode chamber 12 on the side opposite to the separator 28 of the positive electrode 16, and communicates gas between the positive electrode 16 and the upper space of the positive electrode chamber 12. Further, a negative electrode gas flow path structure 24 is provided in the negative electrode chamber 14 on a side opposite to the separator 28 of the negative electrode 18, and communicates gas between the negative electrode 18 and an upper space of the negative electrode chamber 14. Needless to say, a current collector, a wiring, and / or a terminal are connected to the positive electrode 16 and the negative electrode 18, respectively, so that electricity can be taken out of the zinc secondary battery 100. In such a zinc secondary battery 100, the positive electrode 16 and the negative electrode 18 are surely separated by the separator structure 20 including the separator 28 having hydroxide ion conductivity but not having water permeability. Accordingly, the zinc dendrite that grows from the negative electrode toward the positive electrode is prevented by the separator 28, whereby a short circuit between the positive and negative electrodes due to the zinc dendrite can be effectively prevented.

As described above, in the zinc secondary battery 100 including the separator structure 20 including the hydroxide ion conductive separator 28, the positive electrode chamber 12 and the negative electrode chamber 14 are formed on the opposite sides of the positive electrode 16 and the negative electrode 18 from the separator 28. By providing gas passage structures 22 and 24 for gas communication with the upper space of the electrode chamber of each of the above, excellent separator characteristics effective in preventing a short circuit due to zinc dendrite are secured, and overcharge resistance is improved. An improved zinc secondary battery can be provided. That is, when overcharged in a nickel zinc battery or the like, oxygen (O ₂ ) can be generated at the positive electrode, but a separator having no water permeability has a high degree of denseness such that substantially only hydroxide ions pass therethrough. Thus, impervious to _{O 2.} In this regard, according to the zinc secondary battery having the configuration of the present invention, O ₂ generated in the positive electrode 16 at the time of overcharging passes through the positive electrode gas flow path structure 22 on the side opposite to the separator 28 of the positive electrode 16 to the upper space. O _{2 that} has escaped and moved to the upper space can reach the negative electrode 18 through the negative electrode gas flow path structure 24 on the opposite side of the negative electrode 18 from the separator 28. At this time, O ₂ moves on the side opposite to the separator 28 of the positive electrode 16 and the negative electrode 18, so that the hydroxide ion conduction performed through the separator 28 does not need to be hindered. In this way, O ₂ can escape to the upper side of the positive electrode and be sent to the negative electrode side through the upper space, whereby Zn of the negative electrode can be oxidized by O ₂ and returned to ZnO. Through such an oxygen reaction cycle, in a zinc secondary battery provided with a separator structure including a hydroxide ion conductive separator, the overcharge resistance is improved without impairing the hydroxide ion conductivity of the separator. Can be done.

  Such a battery configuration according to the present invention is particularly suitable for providing a zinc secondary battery in the form of a stacked battery having a simple structure that is easy to assemble. Examples of such a laminated battery include a laminated battery using an open-top battery cartridge 10 as shown in FIGS. 1 to 3 and an open-top electrode cartridge 11 as shown in FIGS. Stacked batteries. In the present specification, the battery cartridge is a battery built-in component that accommodates the positive electrode 16, the negative electrode 18, and the separator structure 20 in a water-impermeable container that is open at the top and that can be handled independently. In this specification, the electrode cartridge is a water-impermeable container that is open at the top and contains an electrode for a zinc secondary battery (that is, the negative electrode 18 or the positive electrode 16) and can be handled independently. This is a component with built-in electrodes. An electrolytic solution may be charged in the battery cartridge 10 and the electrode cartridge 11 in advance. The water-impermeable container that constitutes the battery cartridge 10 and the electrode cartridge 11 may be entirely formed of a hard member (typically, a rigid member), or may be partially or entirely formed of a flexible film or the like. The water-impermeable container may be in the form of a flexible pack or a flexible bag in the latter case. The battery cartridge 10 can function as a unit battery in a sealed zinc secondary battery by being accommodated in the sealed container 102 in a state where an electrolyte is contained therein. The electrode cartridge 11 is housed in a sealed container 102 together with a counter electrode (the positive electrode 16 or the negative electrode 18) in a state where an electrolyte is also contained therein, so that the electrode cartridge 11 can be used as a main component of a sealed zinc secondary battery. Can work. In any case, it is sufficient to ensure the hermeticity in the hermetically sealed container 102 that is to be finally accommodated, so that the battery cartridge 10 and the electrode cartridge 11 can have a simple configuration with an open top. That is, when preparing the battery cartridge 10 and the electrode cartridge 11, it is possible to prepare the cartridge with an extremely simple configuration in which the upper part is left open without sealing the upper end part. Then, as shown in FIGS. 1 to 3, only the plurality of battery cartridges 10 are accommodated in the sealed container 102, or as shown in FIGS. In this case, the zinc secondary battery 100 in the form of a laminated battery having overcharge resistance can be provided only by alternately housing the positive electrode 16) in the closed container 102. In this manner, the sealed zinc secondary battery 100 as a stacked battery having a desired number of layers can be assembled very easily. In particular, in the case of a stacked battery using the electrode cartridge 11 as shown in FIGS. 4 and 5, the stacking of a plurality of flexible films is not required, and the housing section (for example, the positive electrode 16) for the counter electrode (for example, the positive electrode 16) (Positive electrode chamber) can be provided as a common storage compartment without being isolated from each other, so that it is possible to provide a stacked battery with a greatly simplified configuration that is extremely easy to manufacture.

  As described above, the battery cartridge 10 and the electrode cartridge 11 have an advantage that a laminated battery can be extremely easily manufactured. Normally, when a zinc secondary battery is configured as a stacked battery, it is assumed that each of the cells is housed in a closed container and sealed in a liquid-tight manner to prevent leakage of the electrolytic solution. The complicated operation is very troublesome and troublesome, and the more the number of layers of the stacked battery is, the more remarkable the trouble becomes. In this regard, in the battery cartridge 10 and the electrode cartridge 11, since the battery or the electrode is housed in the water-impermeable container opened at the top and has the separator 28, the electrolyte (not shown) is placed in the closed container 102. ) And if necessary, the counter electrode is inserted, and the basic configuration of the battery is completed. For this reason, no troublesome sealing structure and sealing work for the upper end portion is required. Moreover, the battery cartridge 10 or the electrode cartridge 11 can be formed while imparting sufficient liquid tightness only by sealingly joining the separator structure 20 and the water-impermeable partition member 26 by heat sealing or the like. The troublesome sealing operation required for the battery container is greatly reduced (or can be eliminated at all). Therefore, the number of layers of the stacked battery can be easily increased. However, it is needless to say that a sealed battery is desirable for practical use. However, the hermeticity of the battery is as follows. It can be easily realized simply by sealing the terminal (in this case, it is needless to say that necessary terminal connections should be made). In addition, since the hardness of the battery container is only required to be ensured by the separately prepared sealed container 102, the battery cartridge 10 and the electrode cartridge 11 are not necessarily required to be hard, and it can be said that the degree of freedom in selecting the material of the cartridge is high. .

  According to a preferred embodiment of the present invention, the zinc secondary battery 100 further includes a water-impermeable partition member 26 that partitions the positive electrode chamber 12 and / or the negative electrode chamber 14 together with the separator structure 20. The member 26 itself, or a combination of the water-impermeable partition member 26 and the separator structure 20, forms a top-open water-impermeable container. The configuration in which the water-impermeable partition member 26 itself forms a main part of the water-impermeable container is in the form of the battery cartridge 10 as shown in FIGS. The combination with 20 forms a water-impermeable container in the form of an electrode cartridge 11 as shown in FIGS. In any case, the water-impermeable partition member 26 is liquid-tightly sealed and joined so that an internal space (that is, the positive electrode chamber 12 and / or the negative electrode chamber 14) can be formed in the separator structure 20. As long as it constitutes a water-impermeable container with an open top (ie, a water-impermeable material), any material may be used regardless of rigidity and flexibility. Examples of the water-impermeable partition member 26 include not only a flexible film 26a as shown in FIGS. 1 and 4, but also a rigid plate 26b as shown in FIGS. That is, the water-impermeable partition member 26 is preferably a flexible film or a rigid plate. The rigid plate 26b preferably has an outer edge wall protruding at both left and right ends and a lower end to secure a space for accommodating the positive electrode 16 and the negative electrode 18, and the outer edge wall is sealed with the separator structure 20 (preferably the frame 32 thereof). Preferably, they are joined.

  As shown in FIGS. 1 and 4, when the water-impermeable partitioning member 26 includes the flexible film 26 a, the plurality of battery cartridges 10 or the electrode cartridges 11 are housed in the sealed container 102 for the zinc secondary battery 100. At this time, there is an advantage that a plurality (preferably as many as possible) of the battery cartridges 10 or the electrode cartridges 11 can be easily packed in the closed container 102 without much concern about design requirements such as dimensional tolerances. . That is, even if the battery cartridge 10 is relatively roughly packed, the stress is easily dispersed by the flexibility of the battery cartridge 10 or the electrode cartridge 11 (and the fluidity of the electrolytic solution therein), and the structural stability and the performance stability are secured. You. Preferably, the flexible film 26a includes a resin film. The resin film preferably has resistance to an alkali metal hydroxide such as potassium hydroxide and can be bonded by heat fusion. For example, a PP (polypropylene) film, a PET (polyethylene terephthalate) film , PVC (polyvinyl chloride) film and the like. As the flexible film including the resin film, a commercially available laminate film can be used, and a preferable laminate film has a structure of two or more layers including a base film (for example, a PET film or a PP film) and a thermoplastic resin layer. A heat laminated film is exemplified. The preferred thickness of the flexible film (for example, a laminated film) is 20 to 500 μm, more preferably 30 to 300 μm, and still more preferably 50 to 150 μm. In the case of the battery cartridge 10, the outer edges of the pair of flexible films 26a other than the upper ends are sealed and joined to each other with the separator structure 20 (preferably the frame 32 or the flexible film 34) interposed therebetween. Thus, the positive electrode electrolyte and the negative electrode electrolyte can be reliably held in the water-impermeable container without liquid leakage. In the case of the electrode cartridge 11, the outer edge of the flexible film 26 a other than the upper end portion is sealingly joined to the separator structure 20 (preferably the frame 32) so that the positive electrode electrolyte or the negative electrode electrolyte can be leaked without leakage. It can be reliably held in the water-impermeable container. The sealing joint is preferably performed by an adhesive or heat fusion. The adhesive is preferable because an epoxy resin-based adhesive is particularly excellent in alkali resistance. The sealing and joining by heat fusion may be performed using a commercially available heat sealing machine or the like. The upper end of the water-impermeable container does not need to be sealed by heat sealing, and therefore can accommodate the battery member with a simple configuration.

  On the other hand, as shown in FIGS. 2, 3 and 5, when the water-impermeable partitioning member 26 includes the rigid plate 26b, the water-impermeable partitioning member 26 becomes a rigid battery cartridge 10 or an electrode cartridge 11, so that handleability, structural stability and performance stability are improved. This has the advantage that the film has improved durability, is less likely to be damaged such as a film tear, and has high durability. The rigid plate 26b preferably includes a resin plate. The resin constituting the rigid plate 26b is preferably a resin having resistance to an alkali metal hydroxide such as potassium hydroxide, more preferably a polyolefin resin, an ABS resin, a PP resin, a PE resin, or a modified polyphenylene ether. And more preferably an ABS resin, a PP resin, a PE resin, or a modified polyphenylene ether. By sealing and joining the outer edges other than the upper end portion to the separator structure 20, the positive electrode electrolyte and / or the negative electrode electrolyte can be reliably held in the water-impermeable container without liquid leakage. The sealing joint is preferably performed by an adhesive or heat fusion. The adhesive is preferable because an epoxy resin-based adhesive is particularly excellent in alkali resistance.

Gas flow path structure The positive gas flow path structure 22 is provided in the positive electrode chamber 12 on the side opposite to the separator 28 of the positive electrode 16, and makes gas communication between the positive electrode 16 and the upper space of the positive electrode chamber 12. The negative electrode gas flow path structure 24 is provided in the negative electrode chamber 14 on the side opposite to the separator 28 of the negative electrode 18, and communicates gas between the negative electrode 18 and the upper space of the negative electrode chamber 14. A positive electrode gas channel structure 22 and a negative electrode gas channel structure 24 (both may be referred to as a gas channel structure hereinafter). The gas flow path structures 22 and 24 are not particularly limited as long as they can provide a flow path suitable for efficiently sending oxygen gas (O ₂ ) generated in the positive electrode 16 to the negative electrode 18 through the upper space. Instead, it can have various structures.

  According to a preferred embodiment of the present invention, as shown in FIGS. 1 and 2, the cathode gas passage structure 22 and / or the anode gas passage structure 24 include a gas passage member 25 having a void functioning as a gas passage. May be included. The gas flow path member 25 preferably has a mesh, non-woven, woven, slender, or porous structure. The material of the gas passage member 25 is not particularly limited. For example, in the case of the gas flow path member 25 having a mesh shape, it is preferable that the gas flow path member 25 is formed of a metal or resin such as copper, nickel, or polypropylene resin. Further, in the case of the slanted gas flow path member 25, a slanted resin plate is preferable, but a slanted metal plate may be used. It is preferable that the gas flow path member 25 does not contain the electrolytic solution (that is, it is in gas communication with the upper space) because the oxygen gas can easily pass therethrough. This state can be realized, for example, by charging the electrolyte so as to wet the electrodes. It is preferable that the outer circumferences of the positive electrode 16 and the negative electrode 18 are not covered with anything so that the oxygen gas can be released from the positive electrode 16 and the oxygen gas can be efficiently absorbed by the negative electrode 18.

  According to another preferred embodiment of the present invention, as shown in FIG. 3, the cathode gas passage structure 22 is provided as a gas passage provided on the inner surface of the water-impermeable partition member 26 on the cathode 16 side. The concave / convex shape including the concave / convex shape 27a providing a functioning void and / or the negative gas flow channel structure 24 provided on the negative surface of the water-impermeable partition member on the negative electrode side and providing a void serving as a gas flow channel. 27a. In this case, the zinc secondary battery can be manufactured with a smaller number of parts without separately using another member such as the gas flow path member 25, so that the productivity is improved. In this case, as shown in FIG. 3, the water-impermeable partition member 26 provided with the concavo-convex shape 27a is a rigid plate 26b that prevents deformation of the gas flow path structure and stably serves as a flow path. Although it is preferable because it can function, the flexible film 26a may be used. Alternatively, the positive electrode 16 and / or the negative electrode 18 may be provided with a concavo-convex shape instead of or together with the water-impermeable partition member 26. For example, the positive electrode gas channel structure 22 includes a concave / convex shape provided on the surface of the positive electrode 16 on the side opposite to the separator 28 to provide a void that functions as a gas channel, and / or the negative electrode gas channel structure 24 includes: The negative electrode 18 may include a concave / convex shape provided on the surface of the negative electrode 18 on the side opposite to the separator 28 to provide a void functioning as a gas flow path. In any case, the concavo-convex shape 27a may be any shape that provides a desired void, but is lattice-shaped, slit-shaped, or embossed in that the shape can be easily provided and gas can be efficiently passed. Is preferred. For example, an uneven shape such as a lattice shape as shown in FIG. 6 or a slit shape as shown in FIG. 7 is given. It is preferable that the uneven shape 27a does not contain an electrolytic solution (that is, it is in gas communication with the upper space) because oxygen gas can easily pass therethrough. This state can be realized, for example, by charging the electrolyte so as to wet the electrodes. It is preferable that the outer circumferences of the positive electrode 16 and the negative electrode 18 are not covered with anything so that the oxygen gas can be released from the positive electrode 16 and the oxygen gas can be efficiently absorbed by the negative electrode 18.

  According to still another preferred embodiment of the present invention, as shown in FIG. 8, the positive electrode gas flow path structure 22 includes a gap space 27b functioning as a gas flow path provided along the left and right ends of the positive electrode 16, In addition, it is preferable that the negative electrode gas flow path structure 24 includes a gap space 27b functioning as a gas flow path provided along both left and right ends of the negative electrode 18. Also in this case, the zinc secondary battery can be manufactured with a smaller number of parts without separately using another member such as the gas flow path member 25, so that the productivity is improved. Also in this case, as shown in FIG. 8, the water-impermeable partitioning member 26 forming the interstitial space 27b is a rigid plate 26b which prevents deformation of the gas flow path structure and stably serves as a flow path. Although it is preferable because it can function, the flexible film 26a may be used. A member similar to the gas passage member 25 described above, such as a mesh or a nonwoven fabric, may be inserted into the gap space 27b. Alternatively, the same shape as the above-described uneven shape 27a may be provided by slitting the left and right inner surfaces of the water-impermeable partition member 26 including the rigid plate 26b. It is preferable that no electrolytic solution is contained in the gap space 27b (that is, the gap space 27b is in gas communication with the upper space) because oxygen gas can easily pass therethrough. This state can be realized, for example, by charging the electrolyte so as to wet the electrodes. It is preferable that the outer circumferences of the positive electrode 16 and the negative electrode 18 are not covered so that the oxygen gas can be released from the positive electrode 16 and the oxygen gas can be efficiently absorbed by the negative electrode 18.

  As described above, it is preferable that the positive electrode gas channel structure 22 has no positive electrode electrolyte and the negative electrode gas channel structure 24 has no negative electrode electrolyte. This makes it easier for the cathode gas passage structure 22 and the anode gas passage structure 24 to be in gas communication with the upper space (of the cathode chamber 12 and the anode chamber 14), so that oxygen gas can be more efficiently passed. . This state can be realized, for example, by charging the electrolyte so as to wet the electrodes. In addition, water repellency may be provided to the positive electrode gas flow channel structure 22 and / or its periphery, and / or water repellency may be provided to the negative electrode gas flow channel structure 24 and / or its surroundings. With this configuration, it is possible to prevent the flow path from being blocked by the entry of the electrolytic solution into the gas flow path structure. The imparting of water repellency may be performed by any method, for example, by applying a water repellent or surface treating the material itself.

  As described above, various modes can be adopted for each of the positive electrode gas channel structure 22 and the negative electrode gas channel structure 24, but different modes are adopted for the positive electrode gas channel structure 22 and the negative electrode gas channel structure 24. Needless to say, Further, the two or more aspects described above may be appropriately combined in the positive electrode gas channel structure 22 itself, and the two or more aspects described above may be appropriately combined in the negative electrode gas channel structure 24 itself.

Buffer Member As shown in FIGS. 1 to 5, it is preferable that a buffer member 36 capable of holding an electrolytic solution is further provided between the separator 28 and the positive electrode 16 and / or the negative electrode 18. The buffer member 36 is not particularly limited as long as it has a liquid retaining property. Preferred examples include a nonwoven fabric, a woven fabric, a water-absorbing resin, a liquid retaining resin, and the like, and a nonwoven fabric is particularly preferred. In the case of a water-absorbing resin or a liquid-retaining resin, it is preferable that the resin is formed in a granular shape and the granular resin is disposed in a sheet shape. The buffer member 36 can exhibit various functions such as a buffer material, a liquid retaining material, a fall prevention material, a bubble escape material, and the like, so that the constituent particles are prevented from falling from the positive electrode 16 and the negative electrode 18 and / or generated. The electrolyte can be sufficiently brought into contact with and held by the separator 28 while allowing bubbles to escape, so that the hydroxide ion conductivity of the separator 28 can be maximized.

Separator Structure The separator structure 20 is a structure including the hydroxide ion conductive separator 28, separates the positive electrode 16 and the negative electrode 18, and does not have water permeability (preferably water permeability and gas permeability). Therefore, since the positive electrode 16 and the negative electrode 18 are reliably separated by the separator structure 20 including the separator 28, zinc dendrite that grows from the negative electrode 18 toward the positive electrode 16 during charging and discharging is prevented by the separator 28, A short circuit between the positive and negative electrodes due to zinc dendrites can be effectively prevented. Preferably, the separator structure 20 is provided with a frame 32 along the outer periphery of the separator 28, and the outer periphery of the water-impermeable partition member 26 and the separator structure 20 are interposed via the frame 32 except for the upper end. Liquid-tight. This makes it possible to easily manufacture a water-impermeable container incorporating the hydroxide ion conductive separator 28 while ensuring sufficient liquid tightness at the junction between different types of members. As shown in FIGS. 1 to 5, the separator structure 20 preferably includes a frame 32 along the outer edge of the separator 28, and the water-impermeable partition member 26 and the separator structure 20 are interposed via the frame 32. It is preferable that they are adhered in a liquid-tight manner. The frame 32 is preferably a resin frame, and more preferably the water-impermeable partition member 26 and the resin frame 32 are bonded by an adhesive and / or heat fusion. The adhesive is preferably an epoxy resin-based adhesive because it is particularly excellent in alkali resistance, and a hot-melt adhesive may be used. Heat welding includes laser welding, thermocompression bonding, hot plate welding, ultrasonic welding, high frequency welding, and other welding using heating (for example, welding by pressing in a heated mold (eg, a mold), soldering iron). Welding by heating, etc.), and is not particularly limited. In any case, it is desired that liquid-tightness be ensured at the joint between the water-impermeable partition member 26 and the frame 32. The resin constituting the frame 32 is preferably a resin having resistance to an alkali metal hydroxide such as potassium hydroxide, more preferably a polyolefin resin, an ABS resin, a PP resin, a PE resin, or a modified polyphenylene ether, More preferably, it is an ABS resin, a PP resin, a PE resin, or a modified polyphenylene ether. As shown in FIGS. 1 and 4, the separator structure 20 may further include a flexible film 34 along at least a part of the outer edge of the frame 32. As the flexible film 34, the same as the flexible film 26a constituting the water-impermeable partition member 26 described above can be used. Further, the flexible film 34 may be directly adhered along the outer edge of the separator 28 without using the frame 32. More preferably, the flexible film 34 and the resin frame 32 or the flexible film 34 and the separator 28 are bonded by an adhesive and / or heat fusion as described above. For example, bonding or sealing by heat fusion may be performed using a commercially available heat sealing machine or the like.

Separator The separator 28 is a member having hydroxide ion conductivity but not having water permeability (preferably water permeability and gas permeability), and is typically in the form of a plate, a film, or a layer. In the present specification, “having no water permeability” means “a test for determining denseness I” employed in Example 1 described later or a method for measuring the water permeability by a method or configuration equivalent thereto when the object to be measured ( For example, water that has contacted one side of the LDH film and / or the porous substrate does not permeate to the other side. That is, the fact that the separator 28 does not have water permeability means that the separator 28 has a high degree of denseness that is impervious to water, and is not a porous film or other porous material having water permeability. Means For this reason, the configuration is extremely effective in physically preventing penetration of the separator by zinc dendrite generated during charging and preventing short circuit between the positive and negative electrodes. Needless to say, the porous substrate 30 may be attached to the separator 28 as shown in FIGS. In any case, since the separator 28 has hydroxide ion conductivity, it is possible to efficiently transfer necessary hydroxide ions between the positive electrode electrolyte and the negative electrode electrolyte and to charge the positive electrode chamber and the negative electrode chamber. A discharge reaction can be realized. In the case of a nickel zinc secondary battery, the reactions during charging in the positive electrode chamber and the negative electrode chamber are as shown below, and the discharging reaction is reversed.
− Positive electrode: Ni (OH) ₂ + OH ⁻ → NiOOH + H ₂ O + e ⁻
- _{negative: ZnO + H 2 O + 2e} - → Zn + 2OH -

However, the negative electrode reaction is constituted by the following two reactions.
- dissolution reaction of _{ZnO: ZnO + H 2 O +} 2OH - → Zn (OH) 4 2-
- precipitation reaction of ^{_{Zn: Zn (OH) 4 2-}} + 2e - → Zn + 4OH -

The He permeability of the separator 28 per unit area is preferably 10 cm / min · atm or less, more preferably 5.0 cm / min · atm or less, and still more preferably 1.0 cm / min · atm or less. A separator having a He permeability of 10 cm / min · atm or less can extremely effectively suppress the permeation of Zn in the electrolytic solution. For example, as shown in FIG. 25 described later, when the He permeability is 10 cm / min · atm or less, the Zn transmission ratio per unit area when evaluated under water contact is significantly reduced. In this sense, it can be said that the upper limit of the He permeability of 10 cm / min · atm has a critical significance with respect to the Zn permeation suppression effect in the hydroxide ion conductive separator. As described above, it is considered that the separator of this embodiment is capable of effectively suppressing the growth of zinc dendrites when used in a nickel-zinc secondary battery, because the permeation of Zn is significantly suppressed. The He permeability is obtained through a step of supplying He gas to one surface of the separator to allow the He gas to pass through the separator, and a step of calculating the He permeability to evaluate the denseness of the hydroxide ion conductive separator. Measured. The He permeability is calculated by the formula of F / (P × S) using the permeation amount F of the He gas per unit time, the differential pressure P applied to the separator when the He gas permeates, and the membrane area S through which the He gas passes. calculate. By performing gas permeability evaluation using He gas as described above, it is possible to evaluate the presence / absence of denseness at a very high level. As a result, substances other than hydroxide ions (particularly, zinc dendrite growth) It is possible to effectively evaluate a high degree of denseness such as not transmitting (causing Zn) as much as possible (transmitting only a trace amount). This is because the He gas has the smallest structural unit among various kinds of atoms or molecules that can constitute the gas, and has very low reactivity. That is, He forms He gas with He atoms alone without forming molecules. In this regard, since the hydrogen gas is composed of H ₂ molecules, the gas constituent unit is smaller for He atoms alone. In the first place, H ₂ gas is dangerous because it is a combustible gas. Then, by employing the index of the He gas permeability defined by the above-described formula, it is possible to easily perform an objective evaluation of denseness regardless of various sample sizes and differences in measurement conditions. Thus, it can be simply, safely and effectively evaluated whether or not the separator has a sufficiently high density suitable for a separator for a zinc secondary battery. The measurement of the He transmittance can be preferably performed according to the procedure shown in Example 3 described later.

The separator 28 has a Zn permeation ratio per unit area of preferably 10 m ⁻² · h ⁻¹ or less, more preferably 5.0 m ⁻² · h ⁻¹ or less, when evaluated under water contact. It is 4.0 m ^-2 · h ^-1 or less, more preferably 3.0 m ^-2 · h ^-1 or less, and even more preferably 1.0 m ^-2 · h ^-1 or less. Such a low Zn transmission rate means that transmission of Zn in the electrolytic solution can be extremely effectively suppressed. For this reason, it is considered in principle that the growth of zinc dendrite can be effectively suppressed when used in a nickel zinc secondary battery. The Zn transmission rate is determined through a step of transmitting Zn through the separator for a predetermined time and a step of calculating the Zn transmission rate. The permeation of Zn to the separator is achieved by bringing the first aqueous solution containing Zn into contact with one surface of the hydroxide ion conductive separator, and the second aqueous solution or water containing no Zn on the other surface of the separator. This is done by contact. Further, the Zn transmission rate is determined by the Zn concentration C ₁ of the first aqueous solution before the start of the Zn transmission, the liquid volume V ₁ of the first aqueous solution before the start of the Zn transmission, the second aqueous solution or the Zn of the water after the completion of the Zn transmission. Using the concentration C ₂ , the liquid volume V ₂ of the second aqueous solution or water after the completion of Zn permeation, the permeation time t of Zn, and the film area S through which Zn permeates, (C ₂ × V ₂ ) / (C ₁ × V ₁ × t × S). The unit of each parameter of C ₁ , C ₂ , V ₁ , V ₂ , t and S is particularly limited as long as the units of the concentrations C ₁ and C ₂ are aligned and the units of the liquid volumes V ₁ and V ₂ are aligned. However, it is preferable that the unit of the Zn transmission time t be h and the unit of the film area S be m ² . The Zn concentration C1 of the first aqueous solution before the permeation of Zn is preferably in the range of 0.001 to ₁ mol / L, more preferably 0.01 to 1 mol / L, and still more preferably 0.05 to 0.1 mol / L. It is 8 mol / L, particularly preferably 0.2 to 0.5 mol / L, most preferably 0.35 to 0.45 mol / L. Further, the permeation time of Zn is preferably 1 to 720 hours, more preferably 1 to 168 hours, still more preferably 6 to 72 hours, and particularly preferably 12 to 24 hours. By performing the evaluation of Zn permeability using a Zn-containing aqueous solution and a Zn-free liquid as described above, it is possible to evaluate the presence or absence of denseness at an extremely high level. As a result, zinc dendrite can be used in a zinc secondary battery. It is possible to reliably and accurately evaluate a high degree of denseness such that Zn that causes growth is not transmitted as much as possible (only a very small amount is transmitted). Then, by employing the index of the Zn transmission rate defined by the above-described formula, an objective evaluation of the denseness can be easily performed regardless of various sample sizes and differences in measurement conditions. This Zn transmission ratio can be an effective index for determining the difficulty of zinc dendrite precipitation. This is because, when a hydroxide ion conductive separator is used as a separator in a zinc secondary battery, even if Zn is contained in the negative electrode electrolyte on one side (the zinc negative electrode side) of the separator, the other side ( This is because it is theoretically considered that the growth of zinc dendrites in the positive electrode electrolyte is effectively suppressed unless Zn permeates the positive electrode electrolyte (which is essentially free of Zn). Thus, according to this aspect, it is possible to reliably and accurately evaluate whether or not the separator has a sufficiently high density suitable for a zinc secondary battery separator. The measurement of the Zn transmission ratio can be preferably performed according to the procedure shown in Example 3 described later.

  The separator 28 is preferably a ceramic separator made of an inorganic solid electrolyte. By using a hydroxide ion conductive inorganic solid electrolyte as the separator 28, the electrolyte solution between the positive and negative electrodes is isolated and the hydroxide ion conductivity is ensured. And since the inorganic solid electrolyte constituting the separator 28 is typically a dense and hard inorganic solid, it is necessary to physically prevent the penetration of the separator by zinc dendrite generated during charging to prevent a short circuit between the positive and negative electrodes. Becomes possible. As a result, the reliability of a zinc secondary battery such as a nickel zinc battery can be greatly improved. It is desired that the inorganic solid electrolyte body be densified to such a degree that it does not have water permeability. For example, the inorganic solid electrolyte body preferably has a relative density of 90% or more, more preferably 92% or more, and still more preferably 95% or more, as calculated by the Archimedes method. The material is not limited to this as long as it is dense and hard. Such a dense and hard inorganic solid electrolyte body can be manufactured through a hydrothermal treatment. Therefore, a simple green compact that has not been subjected to hydrothermal treatment is not dense and is brittle in a solution, which is not preferable as the inorganic solid electrolyte body of the present invention. However, any manufacturing method can be adopted as long as a dense and hard inorganic solid electrolyte body can be obtained, even if it has not undergone hydrothermal treatment.

  The separator 28 or the inorganic solid electrolyte body may be a composite of a particle group including an inorganic solid electrolyte having hydroxide ion conductivity and an auxiliary component that assists densification and hardening of the particle group. Good. Alternatively, the separator 28 is composed of an open-porous porous body as a base material and an inorganic solid electrolyte (for example, a layered double hydroxide) deposited and grown in the pores so as to fill the pores of the porous body. It may be a complex. Examples of the substance constituting the porous body include ceramics such as alumina and zirconia, and insulating substances such as a porous sheet made of a foamed resin or a fibrous substance.

The inorganic solid electrolyte body has a general formula: M ²⁺ _1−x M ³⁺ _x (OH) _{2 An} ⁻ _{x / n} · mH ₂ O (where M ²⁺ is a divalent cation and M ³⁺ is 3 Is a cation having a valence, An ^- is an anion having a valence of n, n is an integer of 1 or more, x is 0.1 to 0.4, and m is 0 or more. And preferably comprises a layered double hydroxide (LDH) having the formula: In the above general formula, M ²⁺ may be any divalent cation, but preferred examples include Mg ²⁺ , Ca ²⁺ and Zn ²⁺ , more preferably Mg ²⁺ . M ³⁺ can be any trivalent cation, but preferred examples include Al ³⁺ or Cr ³⁺ , more preferably Al ³⁺ . A ^n- may be any anion, preferred examples OH ^- and _CO ^{3 2-} and the like. Therefore, in the general ^{formula, M 2+} comprises ^{Mg 2+, M 3+} comprises ^{Al 3+, A n-is} OH ^- and / or _CO preferably contains ^{3 2-.} n is an integer of 1 or more, preferably 1 or 2. x is from 0.1 to 0.4, preferably from 0.2 to 0.35. It is also possible to replace the part or all of the M ³⁺ in the general formula tetravalent or higher valency cation, in which case, the anion A ^n- coefficients x / n of the above general formula It may be changed as appropriate. m is an arbitrary number meaning the number of moles of water, and is a real number or an integer of 0 or more, typically more than 0 or 1 or more.

  It is preferable that the inorganic solid electrolyte body is densified by hydrothermal treatment (that is, a hydrothermal compound). Hydrothermal treatment is extremely effective for integrally densifying a layered double hydroxide, particularly an Mg-Al type layered double hydroxide. For densification by hydrothermal treatment, for example, as described in Patent Document 1 (International Publication No. WO 2013/118561), pure water and a plate-like compact are placed in a pressure vessel, and 120 to 250 ° C, preferably, The reaction can be performed at a temperature of 180 to 250 ° C. for 2 to 24 hours, preferably 3 to 10 hours. However, a more preferable manufacturing method using the hydrothermal treatment will be described later.

  The porous substrate 30 may be provided on one side or both sides of the separator 28. When the porous substrate 30 is provided on one surface of the separator 28, the porous substrate 30 may be provided on the surface of the separator 28 on the negative electrode side, or may be provided on the surface of the separator 28 on the positive electrode side. It goes without saying that the porous substrate 30 has water permeability, so that the positive electrode electrolyte and the negative electrode electrolyte can reach the separator 28, but the presence of the porous substrate 30 allows It is also possible to stably retain hydroxide ions. Further, since the strength can be given by the porous base material 30, the separator 28 can be thinned to reduce the resistance. In addition, a dense film or layer of an inorganic solid electrolyte (preferably LDH) can be formed on or in the porous substrate 30. When a porous substrate is provided on one surface of the separator 28, a method of preparing a porous substrate and forming an inorganic solid electrolyte on the porous substrate may be considered (this method will be described later). On the other hand, when a porous substrate is provided on both surfaces of the separator 28, it is conceivable to perform densification by sandwiching a raw material powder of an inorganic solid electrolyte between two porous substrates. Although the porous substrate 30 is provided over the entire surface of one surface of the separator 28 in FIGS. 1 to 5, the porous substrate 30 may be provided only on a part of one surface of the separator 28 (for example, a region involved in charge / discharge reaction). . For example, when the inorganic solid electrolyte body is formed in a film shape or a layer shape on or in the porous substrate 30, the porous substrate 30 is provided over the entire surface of one side of the separator 28 due to the manufacturing method. Typically. On the other hand, when the inorganic solid electrolyte body is formed in a self-standing plate shape (which does not require a base material), the porous base material 30 is formed only on a part of one surface of the separator 28 (for example, a region involved in the charge / discharge reaction). May be retrofitted, or the porous substrate 30 may be retrofitted over the entire surface on one side.

The inorganic solid electrolyte body may be in any form of a plate, a film, or a layer.If the inorganic solid electrolyte is in the form of a film or a layer, the inorganic solid electrolyte in the form of a film or a layer is formed on or on a porous substrate. It is preferably formed therein. In the case of a plate-like form, sufficient rigidity can be secured and penetration of zinc dendrites can be more effectively prevented. On the other hand, in the case of a film or layer having a thickness smaller than that of the plate, the advantage that the resistance of the separator can be significantly reduced while securing the minimum rigidity for preventing penetration of zinc dendrites is obtained. is there. The preferred thickness of the plate-like inorganic solid electrolyte body is 0.01 to 0.5 mm, more preferably 0.02 to 0.2 mm, and still more preferably 0.05 to 0.1 mm. In addition, the higher the hydroxide ion conductivity of the inorganic solid electrolyte body, the better. However, the inorganic solid electrolyte body typically has a conductivity of 10 ⁻⁴ to 10 ⁻¹ S / m. On the other hand, in the case of a film form or a layer form, the thickness is preferably 100 μm or less, more preferably 75 μm or less, further preferably 50 μm or less, particularly preferably 25 μm or less, and most preferably 5 μm or less. With such a thinness, the resistance of the separator 28 can be reduced. The lower limit of the thickness is not particularly limited because it varies depending on the application, but is preferably 1 μm or more, more preferably 2 μm or more in order to secure a certain degree of rigidity desired as a separator film or layer. is there.

In the case of a positive electrode nickel zinc secondary battery, the positive electrode 16 (typically a positive electrode plate) contains nickel hydroxide and / or nickel oxyhydroxide. For example, when a nickel zinc battery is configured in a discharged state, nickel hydroxide may be used as a positive electrode, and when configured in a fully charged state, nickel oxyhydroxide may be used as a positive electrode. Nickel hydroxide and nickel oxyhydroxide (hereinafter referred to as nickel hydroxide and the like) are positive electrode active materials generally used for nickel-zinc batteries, and are typically in the form of particles. In nickel hydroxide or the like, a different element other than nickel may be dissolved in the crystal lattice thereof, thereby improving the charging efficiency at high temperatures. Examples of such dissimilar elements include zinc and cobalt. Further, nickel hydroxide and the like may be mixed with a cobalt-based component, and examples of such a cobalt-based component include particulates of metallic cobalt and cobalt oxide (for example, cobalt monoxide). . Further, the surface of particles of nickel hydroxide or the like (the dissimilar element may be dissolved therein) may be coated with a cobalt compound. Examples of such a cobalt compound include cobalt monoxide and divalent α-form. Cobalt hydroxide, divalent β-type cobalt hydroxide, compounds of higher cobalt than divalent, and any combinations thereof.

  The positive electrode may further include an additional element in addition to the nickel hydroxide-based compound and a dissimilar element that can be dissolved therein. Examples of such additional elements are scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), Gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erpium (Er), thulium (Tm), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), Rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au) and mercury (Hg), and any combination thereof. The content form of the additional element is not particularly limited, and may be contained in the form of a simple metal or a metal compound (eg, oxide, hydroxide, halide, and carbonate). When a simple metal or a metal compound containing an additional element is added, the addition amount is preferably 0.5 to 20 parts by weight, more preferably 2 to 5 parts by weight, based on 100 parts by weight of the nickel hydroxide-based compound. It is.

  The positive electrode may be configured as a positive electrode mixture by further containing an electrolytic solution or the like. The positive electrode mixture can include nickel hydroxide-based compound particles, an electrolytic solution, and, if desired, a conductive material such as carbon particles, a binder, and the like.

The negative electrode 18 (typically a negative electrode plate) contains zinc and / or zinc oxide. Zinc may be contained in any form of zinc metal, zinc compound and zinc alloy as long as it has electrochemical activity suitable for the negative electrode. Preferable examples of the negative electrode material include zinc oxide, zinc metal, calcium zincate and the like, and a mixture of zinc metal and zinc oxide is more preferable. The negative electrode may be formed in a gel state, or may be mixed with an electrolyte to form a negative electrode mixture. For example, a gelled negative electrode can be easily obtained by adding an electrolytic solution and a thickener to the negative electrode active material. Examples of the thickener include polyvinyl alcohol, polyacrylate, CMC, alginic acid, and the like. Polyacrylic acid is preferable because of its excellent chemical resistance to strong alkalis. When the electrode cartridge 11 is employed as shown in FIGS. 4 and 5, it is preferable that the electrode in the electrode cartridge 11 is the negative electrode 18 and the counter electrode is the positive electrode 16. In this case, even if the shape integrity of the negative electrode is likely to be impaired due to charge / discharge, the shape of the negative electrode 18 is desirably held by the water-impermeable container of the electrode cartridge 11 to continuously participate in charge / discharge. As a result, stable battery performance can be exhibited.

  As the zinc alloy, a zinc alloy containing no mercury and lead, which is known as a non-melonized zinc alloy, can be used. For example, a zinc alloy containing 0.01 to 0.06% by mass of indium, 0.005 to 0.02% by mass of bismuth, and 0.0035 to 0.015% by mass of aluminum has an effect of suppressing hydrogen gas generation. It is preferred. In particular, indium and bismuth are advantageous in improving discharge performance. When a zinc alloy is used for a negative electrode, by reducing the rate of self-dissolution in an alkaline electrolyte, hydrogen gas generation can be suppressed and safety can be improved.

  Although the shape of the negative electrode material is not particularly limited, it is preferably in the form of a powder, whereby the surface area increases and it becomes possible to cope with a large current discharge. The preferred average particle size of the negative electrode material is in the range of 90 to 210 μm in the case of a zinc alloy. When the average particle size is within this range, the surface area is large, so that it is suitable for large-current discharge. It is easy to mix evenly, and the handleability during battery assembly is good.

It is preferable that the current collector zinc secondary battery 100 further includes a positive electrode current collector 17 provided in contact with the positive electrode 16, and the positive electrode current collector 17 exceeds the upper end of the positive electrode 16 or the water-impermeable partition member 26. It is preferable to extend. Further, the zinc secondary battery 100 preferably further includes a negative electrode current collector 19 provided in contact with the negative electrode 18, and the negative electrode current collector 19 extends beyond the upper end of the negative electrode 18 or the water-impermeable partition member 26. Preferably, it extends. In particular, it is preferable that the extending portion of the positive electrode current collector 17 and the extending portion of the negative electrode current collector 19 extend at different positions (for example, symmetrical positions). It is particularly preferred that the protruding portions are connected to each other and / or the extending portions of the plurality of negative electrode current collectors 19 are connected to each other. Alternatively, the positive electrode 16 and the negative electrode 18 may be connected to the separately provided positive electrode terminal and negative electrode terminal inside or outside the battery cartridge 10, the electrode cartridge 11, or the sealed container 102, respectively. Preferred examples of the positive electrode current collector include a nickel porous substrate such as a foamed nickel plate. In this case, for example, by uniformly applying a paste containing an electrode active material such as nickel hydroxide on a nickel porous substrate and drying the paste, a positive electrode plate composed of a positive electrode / a positive electrode current collector can be preferably produced. . At this time, it is also preferable to press the dried positive electrode plate (that is, the positive electrode / positive electrode current collector) to prevent the electrode active material from falling off and to improve the electrode density. Preferred examples of the negative electrode current collector include a copper punched metal. In this case, for example, a mixture comprising a zinc oxide powder and / or a zinc powder and, if desired, a binder (for example, polytetrafluoroethylene particles) is applied on a copper punched metal, and a negative electrode / a negative electrode current collector is formed. Plates can be preferably made. At this time, it is also preferable to press the dried negative electrode plate (that is, the negative electrode / negative electrode current collector) to prevent the electrode active material from falling off and to improve the electrode density.

Electrolyte In the case of a typical zinc secondary battery such as a nickel zinc secondary battery, the positive electrode electrolyte and the negative electrode electrolyte contain an alkali metal hydroxide. That is, an aqueous solution containing an alkali metal hydroxide is used as the positive electrode electrolyte and the negative electrode electrolyte. Examples of the alkali metal hydroxide include potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonium hydroxide and the like, with potassium hydroxide being more preferred. In order to suppress self-dissolution of the zinc alloy, a zinc compound such as zinc oxide or zinc hydroxide may be added to the electrolytic solution. As described above, the positive electrode electrolyte and the negative electrode electrolyte may be mixed with the positive electrode and / or the negative electrode to be present in the form of the positive electrode mixture and / or the negative electrode mixture. Further, the electrolyte may be gelled in order to prevent leakage of the electrolyte. As the gelling agent, it is desirable to use a polymer that absorbs the solvent of the electrolytic solution and swells, and polymers such as polyethylene oxide, polyvinyl alcohol, and polyacrylamide and starch are used.

The material of the sealed container sealed container 102 is not particularly limited as long as it has resistance to alkali metal hydroxides such as potassium hydroxide, polyolefin resins, ABS resins, is preferably made of a resin of the modified polyphenylene ether, More preferred is an ABS resin or a modified polyphenylene ether. In the sealed container 102, the plurality of battery cartridges 10 and the plurality of electrode cartridges 11 may be connected in series with each other, or may be connected in parallel with each other. Since the battery cartridge 10 and the electrode cartridge 11 are open at the top, it goes without saying that the battery cartridge 10, the electrode cartridge 11 and the counter electrode should be housed vertically in the sealed container 102. The sealed container 102 typically includes a main body and a lid. After the battery cartridge 10 or the electrode cartridge 11 and the counter electrode 104 are accommodated together with the electrolytic solution, and the terminal connection is performed as necessary, It is preferable that the lid is closed and the space between the lid and the housing is sealed by a sealing method such as an adhesive or heat fusion.

LDH separator with porous substrate As described above, the separator with a porous substrate preferably used in the zinc secondary battery of the present invention is a separator made of an inorganic solid electrolyte having hydroxide ion conductivity, and at least the separator And a porous substrate provided on one surface. The inorganic solid electrolyte body is in the form of a film or a layer that is densified so as not to have water permeability. A particularly preferred separator with a porous substrate comprises a porous substrate and a separator layer formed on and / or in the porous substrate, wherein the separator layer has a layered structure as described above. It contains double hydroxide (LDH). The separator layer preferably does not have water permeability and air permeability. That is, the porous material can have water permeability and air permeability due to the presence of the pores, but the separator layer is preferably densified with LDH so as not to have water permeability and air permeability. The separator layer is preferably formed on a porous substrate. For example, as shown in FIG. 9, it is preferable that the separator layer 28 is formed as a dense LDH film on the porous substrate 30. In this case, due to the nature of the porous substrate 30, it is needless to say that the LDH may be formed on the surface of the porous substrate 30 and in the pores near the surface as shown in FIG. Alternatively, as shown in FIG. 10, LDH is densely formed in the porous base material 30 (for example, in the surface of the porous base material 30 and in the pores in the vicinity thereof). The portion may constitute the separator layer 28 '. In this regard, the embodiment shown in FIG. 10 has a configuration in which a portion corresponding to the membrane in the separator layer 28 of the embodiment shown in FIG. 9 is removed, but is not limited to this, and is parallel to the surface of the porous substrate 30. It is only necessary that the separator layer exists. In any case, since the separator layer is densified with LDH so as not to have water permeability and gas permeability, it has hydroxide ion conductivity but does not have water permeability and gas permeability (that is, basically does not have water permeability and gas permeability). (Having only hydroxide ions).

  The porous substrate is preferably one on which and / or an LDH-containing separator layer can be formed, and its material and porous structure are not particularly limited. Although it is typical to form an LDH-containing separator layer on and / or in a porous substrate, an LDH-containing separator layer is formed on a non-porous substrate, and then the non-porous LDH-containing separator layer is formed by various known methods. The porous substrate may be made porous. In any case, it is preferable that the porous substrate has a porous structure having water permeability in that the electrolyte can reach the separator layer when incorporated in a battery as a battery separator.

  The porous substrate is preferably composed of at least one selected from the group consisting of a ceramic material, a metal material, and a polymer material. More preferably, the porous substrate is made of a ceramic material. In this case, preferred examples of the ceramic material include alumina, zirconia, titania, magnesia, spinel, calcia, cordierite, zeolite, mullite, ferrite, zinc oxide, silicon carbide, and any combination thereof, and more preferably. Is alumina, zirconia, titania, and any combination thereof, particularly preferably alumina and zirconia, most preferably alumina. When these porous ceramics are used, it is easy to form an LDH-containing separator layer having excellent denseness. Preferred examples of the metal material include aluminum and zinc. Preferred examples of the polymer material include polystyrene, polyether sulfone, polypropylene, epoxy resin, polyphenylene sulfide, hydrophilized fluororesin (tetrafluorinated resin: PTFE, etc.), and any combination thereof. It is further preferable to appropriately select a material having excellent alkali resistance as a resistance to the electrolytic solution of the battery from the various preferable materials described above.

  The porous substrate preferably has an average pore diameter of 0.001 to 1.5 μm, more preferably 0.001 to 1.25 μm, still more preferably 0.001 to 1.0 μm, and particularly preferably 0.001 to 1.0 μm. ０．７0.75 μm, most preferably 0.001 to 0.5 μm. When the content is within these ranges, it is possible to form a dense LDH-containing separator layer so as not to have water permeability while securing desired water permeability to the porous substrate. In the present invention, the average pore diameter can be measured by measuring the longest distance of the pores based on an electron microscope (SEM) image of the surface of the porous substrate. The magnification of the electron microscope (SEM) image used for this measurement is 20000 times, and all the obtained pore diameters are arranged in order of size, and the upper 15 points and the lower 15 points from the average value are combined at 30 points per visual field. The average value of the two visual fields can be calculated to obtain the average pore diameter. For the length measurement, a length measurement function of SEM software, image analysis software (for example, Photoshop, manufactured by Adobe), or the like can be used.

  The surface of the porous substrate preferably has a porosity of 10 to 60%, more preferably 15 to 55%, and still more preferably 20 to 50%. When the content is within these ranges, it is possible to form a dense LDH-containing separator layer so as not to have water permeability while securing desired water permeability to the porous substrate. Here, the porosity of the surface of the porous substrate is adopted because it is easy to measure the porosity using the image processing described below, and the porosity of the surface of the porous substrate is used. This is because it can be said that the porosity roughly represents the porosity inside the porous substrate. That is, if the surface of the porous substrate is dense, it can be said that the inside of the porous substrate is also dense. In the present invention, the porosity of the surface of the porous substrate can be measured by a method using image processing as follows. That is, 1) an electron microscope (SEM) image (magnification: 10,000 or more) of the surface of the porous substrate is acquired, and 2) a grayscale SEM image is read using image analysis software such as Photoshop (made by Adobe). 3) Create a black-and-white binary image in the order of [Image] → [Color Correction] → [Binarization] 4) Divide the number of pixels occupied by the black part by the total number of pixels in the image to the stoma Rate (%). Note that the porosity measurement by this image processing is preferably performed on a 6 μm × 6 μm area on the surface of the porous base material. In order to obtain a more objective index, three areas selected arbitrarily are used. It is more preferable to use the average value of the obtained porosity.

  The separator layer is formed on the porous substrate and / or in the porous substrate, preferably on the porous substrate. For example, when the separator layer 28 is formed on the porous substrate 30 as shown in FIG. 9, the separator layer 28 is in the form of an LDH dense film, and this LDH dense film is typically made of LDH. Become. When the separator layer 28 'is formed in the porous substrate 30 as shown in FIG. 10, the separator layer 28' may be formed in the porous substrate 30 (typically, the surface of the porous substrate 30 and the vicinity thereof). Since the LDH is formed densely (in the hole), the separator layer 28 'typically includes at least a part of the porous substrate 30 and the LDH. The separator layer 28 'shown in FIG. 10 can be obtained by removing a portion corresponding to the film in the separator layer 28 shown in FIG. 9 by a known method such as polishing or cutting.

  The separator layer preferably does not have water permeability and air permeability. For example, the separator layer does not allow water to permeate even if one side thereof is brought into contact with water at 25 ° C. for one week, and does not allow the helium gas to permeate even if one side thereof is pressurized with helium gas at an internal / external differential pressure of 0.5 atm. . That is, it is preferable that the separator layer is densified with LDH so as not to have water permeability and air permeability. However, when a defect having local and / or accidental water permeability exists in the functional film, the defect is filled with a suitable repairing agent (for example, an epoxy resin or the like) to repair the water-impermeable and water-impermeable material. Gas retentivity may be ensured and such repair agents need not necessarily have hydroxide ion conductivity. In any case, the surface of the separator layer (typically an LDH dense film) preferably has a porosity of 20% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 7% or less. It is as follows. The lower the porosity of the surface of the separator layer, the higher the denseness of the separator layer (typically an LDH dense film), which is preferable. Here, the porosity of the surface of the separator layer is adopted because it is easy to measure the porosity using the image processing described below. This is because it can be said that the porosity is generally represented. That is, if the surface of the separator layer is dense, the inside of the separator layer can be said to be similarly dense. In the present invention, the porosity of the surface of the separator layer can be measured as follows by a method using image processing. That is, 1) an electron microscope (SEM) image (magnification of 10,000 or more) of the surface of the separator layer is obtained, and 2) a grayscale SEM image is read using image analysis software such as Photoshop (made by Adobe). ) A black-and-white binary image is created in the order of [Image] → [Color Correction] → [Binarization]. 4) The porosity is calculated by dividing the number of pixels occupied by the black portion by the total number of pixels in the image. %). The measurement of the porosity by this image processing is preferably performed on a 6 μm × 6 μm area on the surface of the separator layer. In order to obtain a more objective index, the porosity is obtained on three areas arbitrarily selected. More preferably, the average value of the porosity is adopted.

  The layered double hydroxide is composed of an aggregate of a plurality of plate-like particles (that is, LDH plate-like particles), and the plate surfaces of the plurality of plate-like particles are substantially the same as the surface of the porous substrate (substrate surface). Preferably, they are oriented in such a direction as to intersect vertically or diagonally. This embodiment is a particularly preferable and feasible embodiment when the separator layer 28 is formed as an LDH dense film on the porous substrate 30 as shown in FIG. 9, but as shown in FIG. LDH is densely formed in the porous substrate 30 (typically, in the surface of the porous substrate 30 and in the pores in the vicinity thereof), so that at least a part of the porous substrate 30 forms the separator layer 28 '. This can be realized even in the case of configuring.

  That is, it is known that the LDH crystal has the form of plate-like particles having a layered structure as shown in FIG. 11, but the above-described substantially vertical or oblique orientation is caused by the LDH-containing separator layer (for example, a dense LDH film). ) Is a very advantageous property. This is because, in the oriented LDH-containing separator layer (for example, an oriented LDH dense film), the hydroxide ion conductivity in the direction in which the LDH plate-like particles are oriented (that is, the direction parallel to the LDH layer) is perpendicular to this. This is because there is a conductivity anisotropy that is significantly higher than the conductivity in the direction. In fact, the present applicant has obtained the finding that the conductivity (S / cm) in the orientation direction is one order of magnitude higher than the conductivity (S / cm) in the direction perpendicular to the orientation direction in the oriented bulk body of LDH. ing. That is, the substantially vertical or oblique orientation in the LDH-containing separator layer of the present embodiment is such that the conductivity anisotropy that the LDH oriented body can have has a thickness anisotropy (ie, a direction perpendicular to the surface of the separator layer or the porous substrate). ) Is maximized or significantly increased, and as a result, the conductivity in the layer thickness direction can be maximized or significantly increased. In addition, since the LDH-containing separator layer has a layer form, it is possible to realize a lower resistance than a bulk-type LDH. The LDH-containing separator layer having such an orientation easily conducts hydroxide ions in the layer thickness direction. In addition, since it is densified, it is very suitable for a separator in which high conductivity and denseness in the layer thickness direction are desired.

  Particularly preferably, in the LDH-containing separator layer (typically, a dense LDH film), the LDH plate-like particles are highly oriented in a substantially vertical direction. This high degree of orientation is confirmed by the fact that, when the surface of the separator layer is measured by the X-ray diffraction method, the peak of the (003) plane is not substantially detected or detected smaller than the peak of the (012) plane. It is possible (however, when a porous substrate is used in which a diffraction peak is observed at the same position as the peak caused by the (012) plane, the peak of the (012) plane caused by the LDH plate-like particles is used. This is not the case because it cannot be specified). This characteristic peak characteristic indicates that the LDH plate-like particles constituting the separator layer are oriented in a direction substantially perpendicular to the separator layer (that is, in a vertical direction or an oblique direction similar thereto, preferably in a vertical direction). That is, the peak of the (003) plane is known as the strongest peak observed when an unoriented LDH powder is subjected to X-ray diffraction. However, in the oriented LDH-containing separator layer, the LDH plate-like particles are The peak in the (003) plane is not substantially detected or detected to be smaller than the peak in the (012) plane due to the orientation substantially perpendicular to the layer. This is because the (001) plane to which the (003) plane belongs is a plane parallel to the layered structure of the LDH plate-like particles (l is 3 and 6), so that the LDH plate-like particles are used as the separator layer. On the other hand, when the LDH layer structure is oriented in a substantially vertical direction, the LDH layered structure also faces in a substantially vertical direction. As a result, when the surface of the separator layer is measured by an X-ray diffraction method, the (001) plane (l is 3 and 6). This is because the peak of ()) does not appear or hardly appears. In particular, the peak of the (003) plane, when present, tends to emerge more strongly than the peak of the (006) plane. Therefore, it is easier to evaluate the presence or absence of the orientation in the substantially vertical direction than the peak of the (006) plane. I can say. Therefore, in the oriented LDH-containing separator layer, the fact that the peak of the (003) plane is substantially not detected or detected smaller than the peak of the (012) plane suggests a high degree of vertical orientation. It is preferable.

  The separator layer preferably has a thickness of 100 μm or less, more preferably 75 μm or less, further preferably 50 μm or less, particularly preferably 25 μm or less, and most preferably 5 μm or less. With such a thickness, the resistance of the separator can be reduced. Preferably, the separator layer is formed as a dense LDH film on the porous substrate, in which case the thickness of the separator layer corresponds to the thickness of the dense LDH film. When the separator layer is formed in the porous substrate, the thickness of the separator layer corresponds to the thickness of at least a part of the porous substrate and the thickness of the composite layer composed of LDH. When formed over and over the substrate, it corresponds to the total thickness of the LDH dense film and the composite layer. In any case, when the thickness is as described above, a desired low resistance suitable for practical use for a battery application or the like can be realized. The lower limit of the thickness of the LDH alignment film is not particularly limited because it varies depending on the application, but it is preferably 1 μm or more in order to secure a certain degree of rigidity desired as a functional film such as a separator. Preferably it is 2 μm or more.

  The above-described LDH separator with a porous substrate is prepared by (a) preparing a porous substrate, and (b) uniformly adhering a starting substance capable of giving a starting point of LDH crystal growth to the porous substrate, if desired. Then, (c) the LDH film is formed by subjecting the porous substrate to hydrothermal treatment to form an LDH film.

(A) Preparation of porous substrate The porous substrate is as described above, and is preferably composed of at least one selected from the group consisting of a ceramic material, a metal material, and a polymer material. More preferably, the porous substrate is made of a ceramic material. In this case, preferred examples of the ceramic material include alumina, zirconia, titania, magnesia, spinel, calcia, cordierite, zeolite, mullite, ferrite, zinc oxide, silicon carbide, and any combination thereof, and more preferably. Is alumina, zirconia, titania, and any combination thereof, particularly preferably alumina, zirconia (eg, yttria-stabilized zirconia (YSZ)), and combinations thereof. When these porous ceramics are used, the density of the LDH film tends to be easily improved. When a porous substrate made of a ceramic material is used, it is preferable to perform ultrasonic cleaning, cleaning with ion-exchanged water, and the like on the porous substrate.

  As described above, the porous substrate is more preferably made of a ceramic material. The porous substrate made of a ceramic material may be a commercially available product, or may be a product produced according to a known method, and is not particularly limited. For example, ceramic powder (for example, zirconia powder, boehmite powder, titania powder, etc.), methylcellulose, and ion-exchanged water are kneaded at a desired mixing ratio, and the obtained kneaded product is subjected to extrusion molding, and the obtained molded product is subjected to extrusion molding. After drying at 70 to 200 ° C. for 10 to 40 hours, baking at 900 to 1300 ° C. for 1 to 5 hours can produce a porous substrate made of a ceramic material. The mixing ratio of methylcellulose is preferably 1 to 20 parts by weight based on 100 parts by weight of the ceramic powder. The mixing ratio of the ion-exchanged water is preferably 10 to 100 parts by weight based on 100 parts by weight of the ceramic powder.

(B) Attachment of Starting Material If desired, a starting material capable of providing a starting point for LDH crystal growth may be uniformly attached to the porous substrate. After the starting substance is uniformly attached to the surface of the porous substrate in this manner, by performing the subsequent step (c), the highly densified LDH film can be uniformly applied to the surface of the porous substrate. It can be formed uniformly. Preferred examples of such a starting point include a chemical species that provides an anion that can enter between layers of the LDH, a chemical species that provides a cation that can be a component of the LDH, or LDH.

(I) Chemical species that give anions The starting point of LDH crystal growth can be a chemical species that gives anions that can enter between layers of the LDH. Examples of such _{^{anions, CO 3 2-, OH -,}} SO 3 -, SO 3 2-, SO 4 2-, NO 3 -, Cl -, Br -, and any combinations thereof Can be Therefore, a starting material that can provide such a starting point may be uniformly attached to the surface of the porous base material by an appropriate method according to the type of the starting material. By giving a chemical species that gives an anion to the surface, metal cations such as Mg ²⁺ and Al ³⁺ can be adsorbed on the surface of the porous substrate to generate nuclei of LDH. Therefore, by performing the subsequent step (c), a highly densified LDH film can be uniformly formed on the surface of the porous substrate without unevenness.

According to a preferred embodiment of the present invention, the starting substance can be attached by attaching a polymer to the surface of the porous substrate and then introducing a chemical species that gives an anion to the polymer. In this embodiment, the anion is preferably SO ₃ ⁻ , SO ₃ ²⁻ and / or SO ₄ ²⁻ , and the introduction of the species providing such anion into the polymer is performed by a sulfonation treatment. Is preferred. Polymers that can be used are those that can be anionized (especially sulfonated); examples of such polymers include polystyrene, polyethersulfone, polypropylene, epoxy resins, polyphenylene sulfide, and any combination thereof. . In particular, aromatic polymers are preferred in that they are easily anionized (particularly sulfonated), and examples of such aromatic polymers include polystyrene, polyether sulfone, epoxy resin, polyphenylene sulfide, and any of them. Combinations are included. The most preferred polymer is polystyrene. To attach the polymer to the porous substrate, a solution in which the polymer is dissolved (hereinafter, referred to as a polymer solution) is prepared by coating the surface of the porous substrate (preferably the plate-shaped outermost surface of the porous substrate with particles). ) Is preferably performed. The polymer solution can be easily prepared, for example, by dissolving a polymer solid (for example, a polystyrene substrate) in an organic solvent (for example, a xylene solution). It is preferable to prevent the polymer solution from penetrating into the inside of the porous substrate, since uniform coating can be easily realized. In this regard, the application or application of the polymer solution is preferably performed by spin coating in that the coating can be performed very uniformly. The conditions for the spin coating are not particularly limited, but the spin coating may be performed, for example, at a rotation speed of 1000 to 10000 rpm for about 60 to 300 seconds including dripping and drying. On the other hand, in the sulfonation treatment, the porous substrate to which the polymer is attached may be immersed in a sulfonable acid such as sulfuric acid (for example, concentrated sulfuric acid), fuming sulfuric acid, chlorosulfonic acid, sulfuric anhydride, and the like. Technology may be used. The immersion in the sulfonable acid may be performed at room temperature or at a high temperature (for example, 50 to 150 ° C.), and the immersion time is not particularly limited, but is, for example, 1 to 14 days.

According to another preferred embodiment of the present invention, the origin substance can be attached by treating the surface of the porous substrate with a surfactant containing a chemical species that gives an anion as a hydrophilic group. In this case, the anion is preferably SO ₃ ⁻ , SO ₃ ²⁻ and / or SO ₄ ²⁻ . Typical examples of such surfactants include anionic surfactants. Preferred examples of anionic surfactants include sulfonic acid type anionic surfactants, sulfate ester type anionic surfactants, and any combination thereof. Examples of the sulfonic acid type anionic surfactant include sodium formalin condensate of naphthalene sulfonic acid, alkyl 2Na of polyoxyethylene sulfosuccinate, sodium polystyrene sulfonate, sodium dioctyl sulfosuccinate, and triethanolamine polyoxyethylene lauryl ether sulfate. Can be Examples of the sulfate type anionic surfactant include polyoxyethylene lauryl ether sulfate Na. The treatment of the porous substrate with the surfactant is not particularly limited as long as the surfactant can be attached to the surface of the porous substrate, and the solution containing the surfactant is applied to the porous substrate. It may be performed by coating or immersing the porous substrate in a solution containing a surfactant. The immersion of the porous substrate in the solution containing the surfactant may be performed at room temperature or at a high temperature (eg, 40 to 80 ° C.) while stirring the solution, and the immersion time is not particularly limited. is there.

(Ii) Chemical species that give cations The starting point of crystal growth of LDH can be a chemical species that gives a cation that can be a component of the layered double hydroxide. Preferred examples of such a cation include Al ³⁺ . In this case, it is preferable that the starting substance is at least one aluminum compound selected from the group consisting of oxides, hydroxides, oxyhydroxides and hydroxy complexes of aluminum. Therefore, a starting material that can provide such a starting point may be uniformly attached to the surface of the porous member by an appropriate method according to the type of the starting material. By giving a chemical species that gives cations to the surface, anions that can enter between layers of the LDH can be adsorbed on the surface of the porous substrate to generate nuclei of the LDH. Therefore, by performing the subsequent step (c), a highly densified LDH film can be uniformly formed on the surface of the porous substrate without unevenness.

According to a preferred embodiment of the present invention, the starting substance can be attached by applying a sol containing an aluminum compound to the porous member. In this case, examples of preferable aluminum compounds include boehmite (AlOOH), aluminum hydroxide (Al (OH) ₃ ), and amorphous alumina, and boehmite is most preferable. The application of the sol containing the aluminum compound is preferably performed by spin coating in that the coating can be performed very uniformly. The conditions for the spin coating are not particularly limited, but the spin coating may be performed, for example, at a rotation speed of 1000 to 10000 rpm for about 60 to 300 seconds including dripping and drying.

According to another preferred embodiment of the present invention, the attachment of the starting substance is performed by performing a hydrothermal treatment on the porous substrate in an aqueous solution containing at least aluminum to form an aluminum compound on the surface of the porous substrate. be able to. The aluminum compound formed on the surface of the porous substrate is preferably Al (OH) ₃ . In particular, an LDH film on a porous substrate (particularly, a ceramic porous substrate) tends to form crystalline and / or amorphous Al (OH) ₃ at an early stage of growth, and this is used as a nucleus to form LDH. Can grow. Then, after the Al (OH) ₃ is uniformly attached to the surface of the porous base material by the hydrothermal treatment in advance, the step (c) accompanied by the hydrothermal treatment is also performed, so that the surface of the porous base material is The LDH film can be uniformly formed without unevenness. In this embodiment, the step (b) and the subsequent step (c) may be continuously performed in the same closed vessel, or the step (b) and the subsequent step (c) may be separately performed in this order. You may.

When the step (b) and the step (c) are continuously performed in the same closed vessel, the raw material aqueous solution (that is, the aqueous solution containing the LDH constituent element) used in the step (c) described later is directly used in the step (b). Can be used. Even in this case, the hydrothermal treatment in the step (b) is performed in a closed vessel (preferably an autoclave) in an acidic to neutral pH range (preferably pH 5.5 to 7.0) at a temperature of 50 to 70 ° C. By performing the heat treatment in a relatively low temperature range, nucleation of Al (OH) ₃ instead of LDH can be promoted. Further, after the nucleation of Al (OH) ₃ , the pH of the aqueous solution of the raw material is increased by maintaining or raising the temperature at the nucleation temperature and the hydrolysis of urea proceeds, so that the pH range suitable for LDH growth is obtained. (Preferably at a pH of more than 7.0), the process can smoothly proceed to the step (c).

On the other hand, when the step (b) and the step (c) are separately performed in this order, it is preferable to use a different raw material aqueous solution for the step (b) and the step (c). For example, in the step (b), nucleation of Al (OH) ₃ is preferably performed using a raw material aqueous solution mainly containing an Al source (preferably not containing other metal elements). In this case, the hydrothermal treatment in the step (b) may be performed at 50 to 120 ° C. in a closed container (preferably an autoclave) different from the step (c). A preferred example of the raw material aqueous solution mainly containing an Al source is an aqueous solution containing aluminum nitrate and urea and not containing a magnesium compound (for example, magnesium nitrate). By using a raw material aqueous solution containing no Mg, precipitation of LDH can be avoided and nucleation of Al (OH) ₃ can be promoted.

According to still another preferred aspect of the present invention, the deposition of the starting substance is performed by evaporating aluminum on the surface of the porous substrate, and then converting the aluminum to an aluminum compound by a hydrothermal treatment in an aqueous solution. Can be. The aluminum compound is preferably Al (OH) ₃ . In particular, by converting into Al (OH) ₃ , the growth of LDH can be promoted using this as a nucleus. Therefore, after the Al (OH) ₃ is uniformly formed on the surface of the porous substrate by hydrothermal treatment, the step (c) accompanied by the hydrothermal treatment is also performed, so that the surface of the porous substrate is highly formed. The densified LDH film can be uniformly formed without unevenness. Aluminum deposition may be either physical vapor deposition or chemical vapor deposition, but physical vapor deposition such as vacuum deposition is preferred. Further, the aqueous solution used for the hydrothermal treatment for converting aluminum is not particularly limited as long as it has a composition capable of producing Al (OH) ₃ by reacting with Al already given by vapor deposition.

(Iii) LDH as starting point
The starting point for crystal growth can be the LDH. In this case, LDH growth can be promoted starting from the LDH nucleus. Then, after the core of the LDH is uniformly adhered to the surface of the porous substrate, the subsequent step (c) is performed, whereby the highly densified LDH film is unevenly formed on the surface of the porous substrate. And can be formed uniformly.

  According to a preferred embodiment of the present invention, the origin substance can be attached by applying a sol containing LDH to the surface of the porous member. The sol containing LDH may be prepared by dispersing LDH in a solvent such as water, and is not particularly limited. In this case, the coating is preferably performed by spin coating. Spin coating is preferred because coating can be performed very uniformly. The conditions for the spin coating are not particularly limited, but the spin coating may be performed, for example, at a rotation speed of 1000 to 10000 rpm for about 60 to 300 seconds including dripping and drying.

  According to another preferred embodiment of the present invention, the deposition of the starting material is performed by depositing aluminum on the surface of the porous substrate and then removing the aluminum (deposited) in an aqueous solution containing a constituent element of LDH other than aluminum. It can be performed by converting to LDH by hydrothermal treatment. Aluminum deposition may be either physical vapor deposition or chemical vapor deposition, but physical vapor deposition such as vacuum deposition is preferred. The aqueous raw material solution used for the hydrothermal treatment for converting aluminum may be an aqueous solution containing a component other than Al already provided by vapor deposition. Preferred examples of such a raw material aqueous solution include a raw material aqueous solution mainly containing an Mg source, and more preferably an aqueous solution containing magnesium nitrate and urea and not containing an aluminum compound (aluminum nitrate). By including the Mg source, it is possible to form an LDH nucleus together with Al already provided by evaporation.

(C) Hydrothermal treatment A porous substrate (to which a starting material can be attached if desired) is subjected to a hydrothermal treatment in a raw material aqueous solution containing the constituent elements of LDH to form an LDH film on the surface of the porous substrate. A preferred raw material aqueous solution contains magnesium ions (Mg ²⁺ ) and aluminum ions (Al ³⁺ ) at a predetermined total concentration, and contains urea. Due to the presence of urea, ammonia is generated in the solution by utilizing the hydrolysis of urea to increase the pH value (for example, the pH is higher than 7.0, preferably higher than 7.0 and lower than or equal to 8.5) and coexist. LDH can be obtained by the metal ions forming hydroxides. Further, since carbon dioxide is generated in the hydrolysis, LDH in which the anion is a carbonate ion type can be obtained. The total concentration of magnesium ions and aluminum ions (Mg ²⁺ + Al ³⁺ ) contained in the raw material aqueous solution is preferably from 0.20 to 0.40 mol / L, more preferably from 0.22 to 0.38 mol / L, still more preferably. It is 0.24 to 0.36 mol / L, particularly preferably 0.26 to 0.34 mol / L. When the concentration is within such a range, nucleation and crystal growth can proceed in a well-balanced manner, and an LDH film excellent in not only orientation but also denseness can be obtained. In other words, when the total concentration of magnesium ions and aluminum ions is low, crystal growth becomes dominant as compared with nucleation, and the number of particles decreases to increase the particle size. It is considered that generation becomes dominant, and the number of particles increases and the particle size decreases.

Preferably, magnesium nitrate and aluminum nitrate are dissolved in the aqueous raw material solution, whereby the aqueous raw material solution contains nitrate ions in addition to magnesium ions and aluminum ions. In this case, the molar ratio (urea / NO ₃ ⁻ ) of urea to nitrate ion (NO ₃ ⁻ ) in the raw material aqueous solution is preferably 2 to 6, and more preferably 4 to 5.

  The porous substrate may be immersed in the raw material aqueous solution in a desired direction (for example, horizontally or vertically). When the porous substrate is held horizontally, the porous substrate may be suspended, floated, or placed in contact with the bottom of the container.For example, the porous substrate may be suspended in the raw material aqueous solution from the bottom of the container. The material may be fixed. In the case where the porous substrate is held vertically, a jig that can vertically set the porous substrate may be placed at the bottom of the container. In any case, the LDH is applied to the porous substrate in a direction substantially perpendicular to or substantially perpendicular thereto (that is, the LDH plate-like particles have their plate surfaces substantially perpendicularly or obliquely intersect with the surface of the porous substrate (substrate surface)). It is preferable to adopt a configuration or arrangement in which the crystal is grown in such a direction as to perform the above.

  In the raw material aqueous solution, the porous substrate is subjected to hydrothermal treatment to form an LDH film on the surface of the porous substrate. This hydrothermal treatment is preferably performed in a closed vessel (preferably an autoclave) at 60 to 150 ° C, more preferably 65 to 120 ° C, further preferably 65 to 100 ° C, and particularly preferably 70 to 100 ° C. 90 ° C. The upper limit temperature of the hydrothermal treatment may be selected so that the porous substrate (eg, polymer substrate) is not deformed by heat. The rate of temperature rise during the hydrothermal treatment is not particularly limited, and may be, for example, 10 to 200 ° C./h, preferably 100 to 200 ° C./h, and more preferably 100 to 150 ° C./h. The duration of the hydrothermal treatment may be appropriately determined according to the desired density and thickness of the LDH film.

  After the hydrothermal treatment, it is preferable to take out the porous substrate from the closed vessel and wash it with ion-exchanged water.

  In the LDH film manufactured as described above, the LDH plate-like particles are highly densified and are oriented in a substantially vertical direction which is advantageous for conduction. That is, the LDH film typically does not have water permeability (preferably water permeability and gas permeability) due to high density. Further, the LDH constituting the LDH film is composed of an aggregate of a plurality of plate-like particles, and the plurality of plate-like particles have their plate surfaces substantially perpendicularly or obliquely intersecting with the surface of the porous substrate. Typically, they are oriented in the same direction. Therefore, when a dense LDH film having sufficient gas tightness is used for a battery such as a zinc-air battery, improvement in power generation performance can be expected, and a secondary battery of a zinc-air battery using an electrolyte that could not be applied conventionally. It is expected to be applied to separators for preventing zinc dendrite growth and carbon dioxide intrusion, which are major barriers to the formation of carbon dioxide. Similarly, application to nickel-zinc batteries, where zinc dendrite development is a major barrier to practical application, is also expected.

  By the way, the LDH film obtained by the above manufacturing method can be formed on both surfaces of the porous substrate. Therefore, in order to make the LDH film suitable for use as a separator, the LDH film on one surface of the porous substrate is mechanically shaved after film formation, or the LDH film is formed on one surface during film formation. It is desirable to take measures to prevent the film from being formed.

  The present invention will be more specifically described by the following examples.

Example 1 : Preparation and evaluation of LDH separator with porous substrate (1) Preparation of porous substrate Boehmite (manufactured by Sasol, DISPAL 18N4-80), methylcellulose, and ion-exchanged water were added to (boehmite): (methylcellulose). : (Ion-exchanged water) was weighed so as to have a mass ratio of 10: 1: 5, and then kneaded. The obtained kneaded material was subjected to extrusion molding using a hand press to form a plate having a size sufficiently exceeding 5 cm × 8 cm and a thickness of 0.5 cm. The obtained molded body was dried at 80 ° C. for 12 hours and then fired at 1150 ° C. for 3 hours to obtain an alumina porous substrate. The porous substrate thus obtained was cut into a size of 5 cm × 8 cm.

  About the obtained porous base material, the porosity of the porous base material surface was measured by the technique using image processing, and was 24.6%. The measurement of the porosity is carried out by: 1) observing the surface microstructure using a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an acceleration voltage of 10 to 20 kV, and scanning the surface of the porous substrate with an electron microscope ( (SEM) image (magnification of 10000 or more) is acquired. 2) A grayscale SEM image is read using image analysis software such as Photoshop (made by Adobe). 3) [Image] → [Color tone correction] → [2 Tone conversion], a black-and-white binary image was created, and 4) the value obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image was used as the porosity (%). The measurement of the porosity was performed on a region of 6 μm × 6 μm on the surface of the porous substrate. FIG. 12 shows an SEM image of the surface of the porous substrate.

  The average pore diameter of the porous substrate was measured and found to be about 0.1 μm. In the present invention, the average pore size was measured by measuring the longest distance of pores based on an electron microscope (SEM) image of the surface of the porous substrate. The magnification of the electron microscope (SEM) image used for this measurement is 20000 times, and all the obtained pore diameters are arranged in order of size, and the upper 15 points and lower 15 points from the average value, a total of 30 points per visual field The average value of the two visual fields was calculated by using to obtain the average pore diameter. For the length measurement, a length measurement function of SEM software was used.

(2) Washing of porous substrate The obtained porous substrate was subjected to ultrasonic cleaning in acetone for 5 minutes, ultrasonic cleaning in ethanol for 2 minutes, and then ultrasonic cleaning in ion exchanged water for 1 minute.

(3) Preparation of raw material aqueous solution As raw materials, magnesium nitrate hexahydrate (Mg (NO ₃ ) ₂ .6H ₂ O, manufactured by Kanto Chemical Co., Ltd.), aluminum nitrate nonahydrate (Al (NO ₃ ) ₃ .9H ₂ O, manufactured by Kanto Chemical Co., Ltd.) and urea ((NH ₂ ) ₂ CO, manufactured by Sigma-Aldrich) were prepared. Magnesium nitrate hexahydrate and aluminum nitrate nonahydrate were weighed such that the cation ratio (Mg ²⁺ / Al ³⁺ ) became 2 and the total metal ion molar concentration (Mg ²⁺ + Al ³⁺ ) became 0.320 mol / L. Into a beaker, and ion-exchanged water was added thereto to make the total volume 600 ml. After stirring the obtained solution, urea weighed at a ratio of urea / NO ₃ ⁻ = 4 was added to the solution, and further stirred to obtain a raw material aqueous solution.

(4) Film formation by hydrothermal treatment In a Teflon (registered trademark) sealed container (internal capacity 800 ml, stainless steel jacket on the outside), the raw material aqueous solution prepared in the above (3) and the porous base material washed in the above (2) are placed. Both were enclosed. At this time, the substrate was floated and fixed from the bottom of a Teflon (registered trademark) closed container, and was horizontally set so that the solution was in contact with both surfaces of the substrate. Thereafter, a hydrothermal treatment was performed at a hydrothermal temperature of 70 ° C. for 168 hours (7 days) to form a layered double hydroxide alignment film (separator layer) on the substrate surface. After a lapse of a predetermined time, the substrate is taken out of the closed container, washed with ion-exchanged water, and dried at 70 ° C. for 10 hours to obtain a dense film of a layered double hydroxide (hereinafter, referred to as LDH) (hereinafter referred to as a film sample). ) Was obtained on a substrate. The thickness of the obtained film sample was about 1.5 μm. Thus, a layered double hydroxide-containing composite material sample (hereinafter, referred to as a composite material sample) was obtained. Although the LDH film was formed on both surfaces of the porous substrate, the LDH film on one surface of the porous substrate was mechanically scraped off to give the composite material a form as a separator.

(5) Various evaluations (5a) Identification of film sample The film sample was measured with an X-ray diffractometer (Rigaku RINT TTR III) under the following conditions: voltage: 50 kV, current value: 300 mA, measurement range: 10 to 70 °. When the crystal phase of was measured, the XRD profile shown in FIG. 13 was obtained. Regarding the obtained XRD profile, the JCPDS card NO. It identified using the diffraction peak of the layered double hydroxide (hydrotalcite compound) described in 35-0964. As a result, it was confirmed that the membrane sample was a layered double hydroxide (LDH, hydrotalcite compound). In addition, in the XRD profile shown in FIG. 13, peaks due to alumina constituting the porous substrate on which the membrane sample is formed (peaks marked with a circle in the figure) are also observed. .

(5b) Observation of microstructure The surface microstructure of the film sample was observed using a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an acceleration voltage of 10 to 20 kV. FIG. 14 shows an SEM image (secondary electron image) of the surface microstructure of the obtained film sample.

  The cross section of the composite material sample was polished by CP polishing to form a polished cross section, and the microstructure of the polished cross section was observed using a scanning electron microscope (SEM) at an acceleration voltage of 10 to 20 kV. FIG. 15 shows an SEM image of the polished cross-sectional microstructure of the composite material sample thus obtained.

(5c) Measurement of Porosity The porosity of the film surface was measured for the film sample by a method using image processing. The porosity is measured by 1) observing the surface microstructure with a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an accelerating voltage of 10 to 20 kV, and using an electron microscope (SEM) on the surface of the film. An image (magnification of 10000 or more) is acquired. 2) A grayscale SEM image is read using image analysis software such as Photoshop (made by Adobe) or the like. 3) [Image] → [Color tone correction] → [Two gradations] 2), and a value obtained by dividing the number of pixels occupied by the black portion by the total number of pixels of the image is defined as a porosity (%). The measurement of the porosity was performed for a region of 6 μm × 6 μm on the surface of the alignment film. As a result, the porosity of the film surface was 19.0%. Using the porosity of the film surface, the density D (hereinafter, referred to as surface film density) when viewed from the film surface was calculated by D = 100% − (porosity of the film surface), and the result was 81.0%. %Met.

  Further, the porosity of the polished cross section of the film sample was also measured. The measurement of the porosity of the polished cross section was performed in the same manner as described above except that an electron microscope (SEM) image (magnification of 10000 or more) of the polished cross section in the thickness direction of the film was obtained according to the procedure shown in (5b) above. The measurement was performed in the same manner as the porosity of the film surface. The measurement of the porosity was performed on the film portion of the cross section of the alignment film. The porosity calculated from the cross-section polished surface of the film sample in this way is 3.5% on average (average value of three cross-section polished surfaces), and a very high-density film is formed on the porous substrate. It was confirmed that.

(5d) Denseness test I
A denseness determination test was performed as follows to confirm that the membrane sample had such denseness that it did not have water permeability. First, as shown in FIG. 16A, a 0.5 cm × 0.5 cm square is placed at the center on the membrane sample side of the composite material sample 220 (cut out into 1 cm × 1 cm square) obtained in the above (1). The silicone rubber 222 having the opening 222a was adhered, and the obtained laminate was sandwiched between two acrylic containers 224 and 226 and adhered. The acrylic container 224 disposed on the side of the silicone rubber 222 has a bottom that is removed, so that the silicone rubber 222 is bonded to the acrylic container 224 with its opening 222a opened. On the other hand, the acrylic container 226 disposed on the porous substrate side of the composite material sample 220 has a bottom, and the container 226 contains ion-exchanged water 228. At this time, Al and / or Mg may be dissolved in the ion-exchanged water. That is, by assembling the composite material sample 220 upside down, the respective constituent members are arranged such that the ion-exchanged water 228 is in contact with the porous substrate side of the composite material sample 220. After assembling these components and the like, the total weight was measured. After assembling these components and the like, the total weight was measured. Note that a closed vent hole (not shown) is formed in the container 226, and it goes without saying that the container 226 is opened after being turned upside down. As shown in FIG. 16B, the assembly was placed upside down and kept at 25 ° C. for one week, after which the total weight was measured again. At this time, if water droplets adhered to the inner side surface of the acrylic container 224, the water droplets were wiped off. Then, the density was determined by calculating the difference in the total weight before and after the test. As a result, no change was observed in the weight of the ion-exchanged water even after being kept at 25 ° C. for one week. From this, it was confirmed that the membrane sample (that is, the functional membrane) had high density so as not to have water permeability.

(5e) Denseness test II
A denseness determination test was performed as follows to confirm that the membrane sample had such a tightness that it did not have air permeability. First, as shown in FIGS. 17A and 17B, an acrylic container 230 without a lid and an alumina jig 232 having a shape and a size capable of functioning as a lid of the acrylic container 230 were prepared. The acrylic container 230 has a gas supply port 230a for supplying a gas therein. An opening 232a having a diameter of 5 mm is formed in the alumina jig 232, and a depression 232b for mounting a film sample is formed along the outer periphery of the opening 232a. An epoxy adhesive 234 was applied to the depression 232b of the alumina jig 232, and the film sample 236b side of the composite material sample 236 was placed in the depression 232b, and was bonded to the alumina jig 232 in an air-tight and liquid-tight manner. Then, the alumina jig 232 to which the composite material sample 236 is bonded is air-tightly and liquid-tightly adhered to the upper end of the acrylic container 230 using a silicone adhesive 238 so as to completely cover the open portion of the acrylic container 230, A closed container 240 for measurement was obtained. The closed container for measurement 240 was placed in a water tank 242, and the gas supply port 230 a of the acrylic container 230 was connected to a pressure gauge 244 and a flow meter 246 so that helium gas could be supplied into the acrylic container 230. Water 243 was put into the water tank 242, and the closed container for measurement 240 was completely submerged. At this time, the inside of the measurement closed container 240 is sufficiently airtight and liquid-tight, and the film sample 236b side of the composite material sample 236 is exposed to the internal space of the measurement closed container 240, while the composite material sample 236 is exposed. 236 is in contact with the water in the water tank 242 on the porous substrate 236 a side. In this state, helium gas was introduced into the acrylic container 230 through the gas supply port 230a into the sealed container 240 for measurement. The pressure gauge 244 and the flow meter 246 are controlled so that the pressure difference between the inside and outside of the membrane sample 236b becomes 0.5 atm (that is, the pressure applied to the side in contact with the helium gas becomes 0.5 atm higher than the water pressure applied to the opposite side). Then, whether or not bubbles of helium gas were generated in the water from the composite material sample 236 was observed. As a result, generation of bubbles due to helium gas was not observed. Therefore, it was confirmed that the membrane sample 236b had high density so as not to have air permeability.

Example 2 (Reference): Production of Laminated Nickel-Zinc Battery Cartridge This example is an example of producing a laminated battery-type nickel-zinc battery cartridge (cell pack) having a positive electrode and a negative electrode separated by a separator structure. It is not a production example of the zinc secondary battery of the present invention in that it does not have a structure and a negative electrode gas flow path structure, and thus corresponds to a reference example in that it is not a production example of the zinc secondary battery of the present invention. An electrode cartridge usable in the zinc secondary battery of the present invention is obtained by further providing the positive electrode gas channel structure and the negative electrode gas channel structure in the battery cartridge manufactured in this example. Therefore, it goes without saying that the electrode cartridge of the present invention and a zinc secondary battery provided with the same can be appropriately manufactured by referring to this example.

(1) Production of Separator Structure An LDH film on an alumina substrate was prepared as a separator with a porous substrate in the same procedure as in Example 1. As shown in FIGS. 18A and 18B, a frame 32 made of a modified polyphenylene ether resin was placed along the outer edge of the separator 28 with the porous substrate 30 on the separator 28 side (ie, the LDH film side). At this time, the frame 32 was a square frame, and a step was provided on the inner peripheral edge, and the outer edges of the porous base material 30 and the separator 28 were fitted to the step. On this frame 32, a laminated film (product name: polybag for vacuum sealer, thickness: 50 μm, material: PP resin (base film) and PE resin (thermoplastic resin)) as a flexible film 34 as a flexible film 34 Placed. An opening 34a is formed in the center of the flexible film 34 in advance, and the flexible film 34 is arranged so that the opening 34a corresponds to an open area in the frame 32. The joint between the flexible film 34, the frame 32, and the separator 28 with the porous substrate 30 was heat-sealed and sealed at about 200 ° C. using a commercially available heat sealing machine. FIG. 19 shows a photograph of the separator structure thus manufactured. A region H indicated by a dotted line in FIG. 19 is a region where the heat sealing is performed, and the liquid tightness in this region is ensured. Five such separator structures 20 were produced.

(2) Preparation of positive electrode plate Nickel hydroxide particles to which zinc and cobalt are added so as to form a solid solution are prepared. The nickel hydroxide particles were coated with cobalt hydroxide to obtain a positive electrode active material. A paste is prepared by mixing the obtained positive electrode active material and a 2% aqueous solution of carboxymethyl cellulose. The paste obtained above is uniformly applied to a current collector made of a nickel metal porous substrate having a porosity of about 95% so that the porosity of the positive electrode active material is 50%, and the paste is dried. A positive electrode plate coated over a predetermined area is obtained.

(3) Preparation of negative electrode plate A mixture consisting of 80 parts by weight of zinc oxide powder, 20 parts by weight of zinc powder and 3 parts by weight of polytetrafluoroethylene particles was applied on a current collector made of a copper punched metal, and the porosity was about At 50%, a negative electrode plate is obtained in which the active material portion is applied over a predetermined area.

(4) Production of Laminated Nickel-Zinc Battery Cartridge A nickel-zinc battery cartridge was assembled by the following procedure using the obtained five separator structures 20, three positive plates, three negative plates, and the like. First, a laminated film (product name: polybag for vacuum sealer, thickness: 50 μm, material: PP resin (base film) and PE resin (thermoplastic resin), manufactured by AS ONE Corporation) is used as a pair of flexible films 26a. Prepared. Three negative plates, five separator structures 20, and three positive plates are laminated on the flexible film 26a such that the negative plates and the positive plates are alternately positioned with the separator structures 20 interposed therebetween. Finally, the flexible film 26a was laminated. At this time, the separator structure 20 was arranged such that the porous substrate 30 and the frame 32 were located on the positive electrode plate side. A photograph of the laminate thus obtained is shown in FIG. The overlapping portions of the flexible films 26a, 34, 26a (that is, the portions to be three outer edges) surrounded by the dotted lines in FIG. 20 were heat-sealed at about 200 ° C. using a commercially available heat sealing machine. FIG. 21 shows a photograph of the water-impermeable container sealed by the heat fusion bonding. 21 is cut along the dotted line in the heat-sealed region to obtain a water-impermeable container whose three outer edges are sealed by heat-sealing bonding as shown in FIG. Was. As can be seen from FIG. 22, the upper end of the water-impermeable container is opened without being heat-sealed and sealed, and the outer edges of the flexible bag body are located at different positions from each other between the positive electrode current collector and the negative electrode current collector. At different positions from each other (corresponding to two metal pieces visually recognized in the figure). Thus, the water-impermeable container containing the five separator structures 20, the positive electrode plate and the negative electrode plate is put in a vacuum desiccator, and the positive electrode chamber and the negative electrode chamber in the water-impermeable container are electrolyzed under a vacuum atmosphere. As a solution, a 6 mol / L KOH aqueous solution was injected as an electrolyte. The injection of the electrolytic solution was performed from the open portion at the upper end of the water-impermeable container. FIG. 22 shows a photograph of the thus-obtained laminated nickel-zinc battery cartridge.

Example 3
In this example, Samples 1 to 10 were prepared as follows as LDH-containing composite material samples (separator samples with a porous substrate) in which a dense layered double hydroxide (LDH) film was formed on a porous substrate. .

(1) Preparation of porous substrate Boehmite (manufactured by Sasol, DISPAL 18N4-80), methylcellulose, and ion-exchanged water were mixed at a mass ratio of (boehmite) :( methylcellulose) :( ion-exchanged water) of 10: 1: After weighing so as to be 5, the mixture was kneaded. The obtained kneaded material was subjected to extrusion molding using a hand press, and was molded into a size of 2.5 cm × 10 cm × 0.5 cm in thickness. The obtained molded body was dried at 80 ° C. for 12 hours and then fired at 1150 ° C. for 3 hours to obtain an alumina porous substrate.

  About the obtained porous base material, the porosity of the porous base material surface was measured by the technique using image processing, and was 24.6%. The measurement of the porosity is carried out by: 1) observing the surface microstructure using a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an acceleration voltage of 10 to 20 kV, and scanning the surface of the porous substrate with an electron microscope ( (SEM) image (magnification of 10000 or more) is acquired. 2) A grayscale SEM image is read using image analysis software such as Photoshop (made by Adobe). 3) [Image] → [Color tone correction] → [2 Tone conversion], a black-and-white binary image was prepared, and 4) the porosity (%) was obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image. The measurement of the porosity was performed on a region of 6 μm × 6 μm on the surface of the porous substrate.

  The average pore diameter of the porous substrate was measured and found to be about 0.1 μm. In the present invention, the average pore size was measured by measuring the longest distance of pores based on an electron microscope (SEM) image of the surface of the porous substrate. The magnification of the electron microscope (SEM) image used for this measurement is 20000 times, and all the obtained pore diameters are arranged in order of size, and the upper 15 points and lower 15 points from the average value, a total of 30 points per visual field The average value of the two visual fields was calculated by using to obtain the average pore diameter. For the length measurement, a length measurement function of SEM software was used.

(2) Washing of porous substrate The obtained porous substrate was subjected to ultrasonic cleaning in acetone for 5 minutes, ultrasonic cleaning in ethanol for 2 minutes, and then ultrasonic cleaning in ion exchanged water for 1 minute.

(3) Polystyrene spin coating and sulfonation Only the samples 1 to 6 were subjected to polystyrene spin coating and sulfonation on the porous substrate by the following procedure. That is, 0.6 g of a polystyrene substrate was dissolved in 10 ml of a xylene solution to prepare a spin coating solution having a polystyrene concentration of 0.06 g / ml. 0.1 ml of the obtained spin coat liquid was dropped on a porous substrate, and applied by spin coating at a rotation speed of 8000 rpm. This spin coating was performed for 200 seconds including dripping and drying. The porous substrate coated with the spin coat solution was immersed in 95% sulfuric acid at 25 ° C. for 4 days for sulfonation.

(4) Preparation of raw material aqueous solution As raw materials, magnesium nitrate hexahydrate (Mg (NO ₃ ) ₂ .6H ₂ O, manufactured by Kanto Chemical Co., Ltd.) and aluminum nitrate nonahydrate (Al (NO ₃ ) ₃ .9H ₂ O, manufactured by Kanto Chemical Co., Ltd.) and urea ((NH ₂ ) ₂ CO, manufactured by Sigma-Aldrich) were prepared. Magnesium nitrate hexahydrate and aluminum nitrate nonahydrate were weighed such that the cation ratio (Mg ²⁺ / Al ³⁺ ) became 2 and the total metal ion molar concentration (Mg ²⁺ + Al ³⁺ ) became 0.320 mol / L. Into a beaker, and ion-exchanged water was added thereto to make a total volume of 75 ml. After stirring the obtained solution, urea weighed at a ratio of urea / NO ₃ ⁻ = 4 was added to the solution, and further stirred to obtain a raw material aqueous solution.

(5) Film formation by hydrothermal treatment In a Teflon (registered trademark) sealed container (internal capacity 100 ml, stainless steel jacket on the outside), the raw material aqueous solution prepared in the above (4) and the porous substrate sulfonated in the above (3) (Samples 1 to 6) or the porous substrates (Samples 7 to 10) washed in the above (2) were enclosed together. At this time, the substrate was floated and fixed from the bottom of a Teflon (registered trademark) closed container, and was horizontally set so that the solution was in contact with both surfaces of the substrate. Thereafter, a hydrothermal treatment was performed at a hydrothermal temperature of 70 to 75 ° C. for 168 to 504 hours to form a layered double hydroxide alignment film on the substrate surface. At this time, ten types of alignment films having various densities were produced by appropriately changing the conditions of the hydrothermal treatment. After a lapse of a predetermined time, the substrate is taken out of the closed container, washed with ion-exchanged water, and dried at 70 ° C. for 10 hours to obtain a dense film of a layered double hydroxide (hereinafter, referred to as LDH) (hereinafter referred to as a film sample). ) Was obtained on a substrate. The thickness of the obtained film sample was about 1.0 to 2.0 μm. Thus, Samples 1 to 10 were obtained as LDH-containing composite material samples (hereinafter, referred to as composite material samples). Although the LDH film was formed on both surfaces of the porous substrate, the LDH film on one surface of the porous substrate was mechanically scraped off in order to give the composite material a form as a separator.

(6a) Identification of film sample The crystal phase of the film sample was measured with an X-ray diffractometer (Rigaku RINT TTR III) under the following conditions: voltage: 50 kV, current value: 300 mA, measurement range: 10 to 70 °. To obtain an XRD profile. Regarding the obtained XRD profile, the JCPDS card NO. Identification was performed using the diffraction peak of the layered double hydroxide (hydrotalcite-type compound) described in 35-0964. As a result, it was confirmed that each of the membrane samples 1 to 10 was a layered double hydroxide (LDH, hydrotalcite compound).

(6b) He Permeation Measurement A He permeation test was performed as follows in order to evaluate the denseness of the membrane samples 1 to 10 from the viewpoint of He permeability. First, the He transmittance measurement system 310 shown in FIGS. 23A and 23B was constructed. In the He permeability measuring system 310, He gas from a gas cylinder filled with He gas is supplied to a sample holder 316 via a pressure gauge 312 and a flow meter 314 (digital flow meter), and the dense gas held in the sample holder 316 is provided. The film 318 is configured to be transmitted from one surface to the other surface and discharged.

  The sample holder 316 has a structure provided with a gas supply port 316a, a closed space 316b, and a gas discharge port 316c, and was assembled as follows. First, an adhesive 322 was applied along the outer periphery of the dense film 318 and attached to a jig 324 (made of ABS resin) having an opening at the center. Gaskets made of butyl rubber are disposed as sealing members 326a and 326b at the upper and lower ends of the jig 324, and supporting members 328a and 328b (made of PTFE) having openings formed by flanges from outside the sealing members 326a and 326b. ). Thus, the closed space 316b was defined by the dense film 318, the jig 324, the sealing member 326a, and the support member 328a. Note that the dense film 318 is in the form of a composite material formed on the porous substrate 320, and is arranged so that the dense film 318 side faces the gas supply port 316a. The support members 328a and 328b were tightly fastened to each other by the fastening means 330 using screws so that the He gas did not leak from a portion other than the gas outlet 316c. The gas supply pipe 334 was connected via a joint 332 to the gas supply port 316a of the sample holder 316 thus assembled.

Next, He gas was supplied to the He permeability measuring system 310 via a gas supply pipe 334, and was allowed to permeate the dense film 318 held in the sample holder 316. At this time, the gas supply pressure and the flow rate were monitored by the pressure gauge 312 and the flow meter 314. After transmitting He gas for 1 to 30 minutes, the He permeability was calculated. The calculation of the He permeability is performed by calculating the permeation amount F of the He gas per unit time F (cm ³ / min), the differential pressure P (atm) applied to the dense membrane when the He gas permeates, and the film area S (cm) through which the He gas permeates. ² ) was calculated by the formula of F / (P × S). The He gas permeation amount F (cm ³ / min) was read directly from the flow meter 314. The gauge pressure read from the pressure gauge 312 was used as the differential pressure P. The He gas was supplied such that the differential pressure P was in the range of 0.05 to 0.90 atm. The obtained result was as shown in Table 1 and FIG.

(6c) Zn permeation test In order to evaluate the densities of the membrane samples 1 to 10 from the viewpoint of Zn permeability, a Zn permeation test was performed as follows. First, a Zn transmission measuring device 340 shown in FIGS. 24A and 24B was constructed. The Zn transmission measurement device 340 includes a flanged opening tube (made of PTFE) in which a flange 362a is integrated with a first tank 344 formed of an L-shaped opening tube, and a second tube formed of an L-shaped tube. A flanged opening tube (made of PTFE) in which a flange 362b is integrated with a tank 346 is disposed so that the flanges 362a and 362b face each other, and a sample holder 342 is disposed therebetween. The structure was such that Zn could be transmitted from one surface to the other surface.

  The assembly of the sample holder 342 and its attachment to the device 340 were performed as follows. First, an adhesive 356 was applied along the outer periphery of the dense film 352 and attached to a jig 358 (made of ABS resin) having an opening at the center. As shown in FIG. 24A, packing made of silicone rubber is provided on both sides of the jig 358 as sealing members 360a and 360b, and a pair of flanged opening pipes 362a are provided from outside the sealing members 360a and 360b. , 362b. Note that the dense film 352 is in the form of a composite material formed on the porous base material 354, and the dense film 352 side is where the first aqueous solution 348 containing Zn is injected. It was arranged to face. The flanges 362a and 362b were tightly fastened to each other by a fastening means 364 using screws so that no liquid leakage occurred between them.

On the other hand, a 9 mol / L KOH aqueous solution in which 2.5 mol / L of Al (OH) ₃ and 0.5 mol / L of ZnO were dissolved was prepared as a first aqueous solution 348 to be put into the first tank 344. The Zn concentration C ₁ (mol / L) of the first aqueous solution was measured by ICP emission spectroscopy, and the results were as shown in Table 1. Further, as a second aqueous solution 350 to be put into the second tank 346, a 9 mol / L KOH aqueous solution in which 2.5 mol / L of Al (OH) ₃ was dissolved without dissolving ZnO was prepared. In the measuring device 340 in which the previously prepared sample holder 342 is incorporated, the first aqueous solution 348 and the second aqueous solution 350 are injected into the first tank 344 and the second tank 346, respectively, and the dense solution held by the sample holder 342 is obtained. Zn was transmitted through the film 352. In this state, after performing Zn permeation at the time t shown in Table 1, the liquid volume V ₂ (ml) of the second aqueous solution was measured, and the Zn concentration C ₂ (mol / L) of the second aqueous solution 350 was measured. It was measured by ICP emission spectroscopy. The Zn transmission rate was calculated using the obtained value. The Zn transmission rate is determined by the Zn concentration C ₁ (mol / L) of the first aqueous solution before the start of Zn transmission, the liquid volume V ₁ (ml) of the first aqueous solution before the start of Zn transmission, and the second concentration after the end of Zn transmission. Zn concentration C ₂ (mol / L) of the aqueous solution, liquid volume V ₂ (ml) of the second aqueous solution after the completion of Zn permeation, Zn permeation time t (min), and film area S (cm) through which Zn permeates ² ), and was calculated by the formula of (C ₂ × V ₂ ) / (C ₁ × V ₁ × t × S). The obtained result was as shown in Table 1 and FIG.

DESCRIPTION OF SYMBOLS 10 Battery cartridge 11 Electrode cartridge 12 Positive electrode chamber 14 Negative electrode chamber 16 Positive electrode 17 Positive electrode current collector 18 Negative electrode 19 Negative electrode current collector 20 Separator structure 22 Positive gas flow path structure 24 Negative gas flow path structure 25 Gas flow path member 26 Water Permeable partition member 26a Flexible film 26b Rigid plate 27a Uneven shape 27b Gap space 28 Separator 30 Porous substrate 32 Frame 34 Flexible film 34a Opening 36 Buffer member 100 Sealed zinc secondary battery 102 Closed container

Claims (21)

A sealed container,
A positive electrode chamber and a negative electrode chamber, which are provided in a closed container and open or communicate with each other at the top,
A positive electrode housed in the positive electrode chamber;
A cathode electrolyte containing the alkali metal hydroxide aqueous solution, which is accommodated in the cathode chamber;
A negative electrode housed in the negative electrode chamber and containing zinc and / or zinc oxide;
A negative electrode electrolyte contained in the negative electrode chamber and containing an aqueous alkali metal hydroxide solution,
A separator structure including a separator provided to partition the positive electrode chamber and the negative electrode chamber, and having a hydroxide ion conductivity but having no water permeability,
A positive electrode gas flow path structure provided on the opposite side of the positive electrode to the separator in the positive electrode chamber and communicating gas between the positive electrode and an upper space of the positive electrode chamber;
A negative electrode gas flow path structure provided on the opposite side of the negative electrode to the separator in the negative electrode chamber, and gas-communicating between the negative electrode and an upper space of the negative electrode chamber;
A zinc secondary battery comprising:
The zinc secondary battery further includes a water-impermeable partition member that partitions the positive electrode chamber and / or the negative electrode chamber together with the separator structure, and the water-impermeable partition member itself or a water-impermeable partition member A zinc battery, wherein the combination of the separator and the separator structure forms a water-impermeable container with an open top.   2. The zinc secondary battery according to claim 1, wherein the positive electrode gas channel structure and / or the negative electrode gas channel structure includes a gas channel member having a void functioning as a gas channel.   3. The zinc secondary battery according to claim 2, wherein the gas flow path member has a mesh shape, a nonwoven fabric shape, a woven fabric shape, a saw blade shape, or a porous structure. 4.   The positive electrode gas channel structure includes a concave / convex shape provided on an inner surface of the water-impermeable partition member on the positive electrode side to provide a void that functions as a gas channel, and / or the negative electrode gas channel structure The zinc alloy according to any one of claims 1 to 3, further comprising a concave / convex shape provided on an inner surface of the water-impermeable partition member on the negative electrode side to form a void functioning as a gas flow path. Next battery.   The positive electrode gas flow path structure includes a concave / convex shape provided on a surface of the positive electrode opposite to the separator and providing a void that functions as a gas flow path, and / or the negative electrode gas flow path structure includes the negative electrode. The zinc secondary battery according to any one of claims 1 to 4, further comprising a concave / convex shape provided on a surface opposite to the separator and providing a void functioning as a gas flow path.   The zinc secondary battery according to claim 4, wherein the uneven shape is a lattice shape, a slit shape, or an emboss shape.   The positive electrode gas flow path structure includes a gap space functioning as a gas flow path provided along left and right ends of the positive electrode, and / or the negative gas flow path structure is provided along left and right ends of the negative electrode. The zinc secondary battery according to any one of claims 1 to 6, comprising a gap space functioning as a gas flow path.   The zinc secondary battery according to any one of claims 1 to 7, further comprising a buffer member capable of holding an electrolytic solution between the separator and the positive electrode and / or the negative electrode.   The water repellency is imparted to the positive electrode gas flow channel structure and / or the periphery thereof, and / or the water repellency is imparted to the negative electrode gas flow channel structure and / or the periphery thereof. 12. The zinc secondary battery according to claim 1.   The separator structure comprises a frame along the outer peripheral edge of the separator, the outer peripheral edge of the water-impermeable partition member and the separator structure, except for the upper end, liquid-tight through the frame. The zinc secondary battery according to any one of claims 1 to 9, which is adhered.   The zinc secondary battery according to any one of claims 1 to 10, wherein the water-impermeable partition member is a flexible film or a rigid plate.   The zinc secondary battery according to any one of claims 1 to 11, wherein the separator is a ceramic separator made of an inorganic solid electrolyte body. The inorganic solid electrolyte has a general formula:
^{_{M 2+ 1-x M 3+ x}} (OH) 2 A n- x / n · mH 2 O
^{(Wherein, M 2+} is a divalent ^{cation, M 3+} is a trivalent ^{cation, A n-is} the n-valent anion, n is an integer of 1 or more, x is 0 13. The zinc secondary battery according to claim 12, comprising a layered double hydroxide having a basic composition of 0.1 to 0.4 and m is 0 or more. The separator structure further includes a porous substrate on one or both surfaces of the separator, and the inorganic solid electrolyte is in the form of a film or a layer, and the film or layer of the inorganic solid electrolyte is the porous material. 14. The zinc secondary battery according to claim 13 , which is formed on or in a porous substrate.   The layered double hydroxide is composed of an aggregate of a plurality of plate-like particles, and the plurality of plate-like particles are oriented such that their plate surfaces cross the surface of the porous substrate substantially perpendicularly or obliquely. The zinc secondary battery according to claim 14, wherein the zinc secondary battery is oriented.   The zinc secondary battery according to any one of claims 1 to 15, wherein the separator has a He permeability per unit area of 10 cm / min · atm or less. The zinc secondary battery according to any one of claims 1 to 16, wherein the separator has a Zn permeation rate per unit area of 10 m- ² · h- ¹ or less when evaluated under water contact.   The zinc secondary battery is provided in contact with the positive electrode, a positive electrode current collector extending beyond the upper end of the positive electrode or the water-impermeable partition member, and provided in contact with the negative electrode, The zinc secondary battery according to any one of claims 1 to 17, further comprising a negative electrode or a negative electrode current collector extending beyond an upper end of the water-impermeable partition member.   19. The zinc secondary battery according to any one of claims 1 to 18, wherein the positive electrode includes nickel hydroxide and / or nickel oxyhydroxide, whereby the zinc secondary battery forms a nickel zinc battery.   The zinc secondary battery according to any one of claims 1 to 19, wherein the positive electrode gas channel structure does not include the positive electrode electrolyte, and the negative electrode gas channel structure does not include the negative electrode electrolyte. The zinc secondary battery according to any one of claims 1 to 20, comprising a plurality of at least one of the positive electrode chamber and the negative electrode chamber.