JP5310284B2 - Metal secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal secondary battery that keeps the battery performance by suppressing an increase of internal resistance even if the volume of an electrode, especially, a negative electrode, changes due to charging or discharging of the battery. <P>SOLUTION: The metal secondary battery includes a power generation unit having a positive electrode, a solid electrolyte layer, a first electrolytic solution layer, and a negative electrode in this order. A first electrolytic solution is contained in the first electrolytic solution layer. Therefore, even if the volume of the negative electrode changes, the first electrolytic solution is filled in between the solid electrolyte layer and the negative electrode. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a metal secondary battery.

  In recent years, from the viewpoint of protecting the global environment, a high-performance and high-capacity high-performance power supply is required to be applied to electric vehicles, hybrid vehicles, and the like as low-pollution vehicles. Also, in fields other than automobiles and the like, secondary batteries capable of improving the performance of mobile tools are required due to the global spread of mobile tools such as information-related devices and communication devices.

  Among secondary batteries, lithium-based metal secondary batteries, in particular, have a large electric capacity that can be discharged in principle and high output, and various studies have been conducted. Examples of the form of the lithium metal secondary battery include a lithium ion secondary battery using a lithium composite oxide or the like as a positive electrode active material, a lithium air battery using oxygen as a positive electrode active material, and the like. In such a lithium-based metal secondary battery, for example, a positive electrode including the positive electrode active material or the like, an electrolyte layer including an electrolyte and / or a solid electrolyte, and a negative electrode including Li or the like are stacked in this order. By generating a battery reaction in the power generation section, electrical energy can be extracted to the outside.

  As a technique related to the secondary battery, a form in which an electrolyte layer and a solid electrolyte layer are used in combination with an electrolyte layer is disclosed. For example, Patent Document 1 discloses a secondary battery including a power generation unit having a lithium negative electrode, a separator containing a non-aqueous electrolyte, OHARA glass (lithium ion conductor), and a positive electrode in this order. Non-Patent Document 1 discloses a secondary battery in which a solid electrolyte (membrane) is provided between a Li negative electrode and a positive electrode, a non-aqueous electrolyte is provided on the Li negative electrode side, and an aqueous electrolyte is provided on the positive electrode side. It is disclosed.

Special table 2007-524204 gazette

J.P. Zheng et al., “Theoretical Energy Density of Li-Air Batteries”, Journal of The Electrochemical Society, 155 (6) A432-A437 (2008)

However, in a metal secondary battery as described in Patent Document 1 or Non-Patent Document 1, when a discharge reaction of the battery occurs, a component (for example, Li) in the negative electrode elutes into the electrolyte as ions (or For example, it is considered that the reaction of depositing as Li ₂ O on the positive electrode side occurs, and the volume of the negative electrode decreases with discharge. When the volume of the negative electrode decreases, the liquid level of the electrolyte solution between the negative electrode and the solid electrolyte is considered to change, and a void is formed between the solid electrolyte and the negative electrode, increasing the internal resistance. There was a risk of adverse effects.

  The present invention has been made in view of the above, and is a case where the volume of an electrode, particularly a negative electrode, is changed by charging or discharging of a battery in a metal secondary battery using a solid electrolyte and an electrolyte together as an electrolyte layer. However, an object of the present invention is to provide a metal secondary battery that can suppress an increase in internal resistance and maintain battery performance.

In order to solve the above problems, the present invention has the following configuration. That is,
The present invention includes a power generation unit having a positive electrode, a solid electrolyte layer, a first electrolyte layer, and a negative electrode in this order, and the first electrolyte layer includes a first electrolyte , and the first electrolyte layer In addition, an electrolyte replenishment part is connected, and the liquid level of the electrolyte contained in the electrolyte solution replenishment part is higher than the position of the first electrolyte solution layer,
The first electrolyte layer and the electrolyte replenishment unit are always in fluid communication,
When the volume of the negative electrode changes, the first electrolytic solution is replenished from the electrolytic solution replenishment unit to the first electrolytic solution layer by the amount of the negative electrode volume change, or from the first electrolytic solution layer Even when the volume of the negative electrode changes due to the movement of the first electrolytic solution to the electrolytic solution replenishment section, the space between the solid electrolyte layer and the negative electrode is filled with the first electrolytic solution. It is a metal secondary battery.

  In the present invention, the “first electrolytic solution” is particularly limited as long as it is an electrolytic solution capable of conducting ions (for example, metal ions) that travel between the positive electrode and the negative electrode by the battery reaction of the metal secondary battery. Instead, a non-aqueous electrolysis solution or an aqueous electrolyte solution can be used. The “first electrolyte solution layer” is a layer containing the first electrolyte solution, and may have other separators and the like. The first electrolyte layer is in contact with both the negative electrode and the solid electrolyte layer, and ion conduction between the negative electrode and the solid electrolyte layer is enabled. “Even when the volume of the negative electrode changes” is a concept that includes the case where the volume of the negative electrode is not changed and the case where the volume of the negative electrode is changed in addition to the case where the volume of the negative electrode is changed. is there. “Filled with the first electrolyte solution” means that, for example, even when the volume of the negative electrode changes as the battery is charged and discharged, no gap is generated between the negative electrode and the solid electrolyte layer. In addition, it means that the space between the negative electrode and the solid electrolyte layer is filled with the first electrolyte so that no voids remain.

In the present invention, the first electrolyte layer, shall be the form of the electrolyte replenishing portion is connected. The “electrolyte replenisher” is not particularly limited as long as the electrolyte can be replenished from the outside of the power generation unit to the first electrolyte layer. By connecting the electrolyte replenishment part to the first electrolyte layer, the electrolyte can be appropriately replenished between the negative electrode and the solid electrolyte layer even when the volume of the negative electrode changes due to charging or discharging of the battery. The space between the negative electrode and the solid electrolyte layer is always filled with the electrolytic solution, and no voids are generated.

In the present invention, when the volume of the negative electrode is changed, only the volume change of the negative electrode, the first electrolyte layer from the electrolyte replenishing unit, the electrolytic solution is replenished, or electrolyte replenishment from the first electrolyte layer in part, it shall be the form in which the electrolyte is moved. When the electrolyte is appropriately replenished or moved (including removal) by the volume change of the negative electrode, the space between the negative electrode and the solid electrolyte layer is always filled with the electrolyte. There is no gap between the two. In addition, the electrolytic solution is not replenished excessively, and the amount of the electrolytic solution is adjusted as appropriate, so there is no waste.

In the present invention, the liquid level of the stored in the electrolyte replenishing portion electrolyte, than the position of the first electrolyte layer is positioned higher, and the liquid level of the electrolyte solution contained in the electrolyte replenishing portion , that has received a predetermined pressure. Here, “the level of the electrolyte contained in the electrolyte replenishment part” refers to the level of the electrolyte surface at the highest position in the electrolyte replenishment part. “Position higher than the position of the first electrolyte layer” means that the level of the electrolyte in the electrolyte replenishment section is the electrolyte in the first electrolyte layer even when the volume of the electrode changes. (In particular, a position higher than the interface position between the first electrolyte layer and the solid electrolyte layer). “The surface of the electrolyte is under a predetermined pressure” means, for example, that when the electrolyte replenisher is a closed system, an inert gas adjusted to a predetermined pressure is electrolyzed inside the electrolyte replenisher. A mode in which the liquid level of the electrolytic solution is subjected to a predetermined pressure by being brought into contact with the liquid level of the liquid, a mode in which the liquid level of the electrolytic solution is subjected to atmospheric pressure when the electrolytic solution replenishment unit is an open system, Can be mentioned. The predetermined pressure is preferably not less than atmospheric pressure. In this way, with a simple configuration, the electrolyte is automatically replenished from the electrolyte replenishment part to the first electrolyte layer or the electrolyte is replenished from the first electrolyte layer as the volume of the negative electrode changes. The electrolyte solution can be automatically removed to the part. Therefore, the space between the negative electrode and the solid electrolyte layer is always filled with the electrolytic solution, and no gap is generated between the negative electrode and the solid electrolyte layer.

  In the present invention, a second electrolyte solution layer containing a second electrolyte solution may be further provided between the positive electrode and the solid electrolyte layer. Here, the “second electrolytic solution” is not particularly limited as long as it is an electrolytic solution capable of conducting ions traveling between the positive electrode and the negative electrode by the battery reaction of the metal secondary battery. Alternatively, an aqueous electrolyte can be used. The “second electrolyte solution layer” is a layer containing a second electrolyte solution, and may have other separators and the like. The second electrolyte layer is in contact with the positive electrode and the solid electrolyte layer, and ion conduction between the positive electrode and the solid electrolyte layer is enabled.

  Further, in the present invention further including the second electrolyte solution layer between the positive electrode and the solid electrolyte layer, the positive electrode electrode even when the electrolyte replenishment portion is connected to the second electrolyte solution layer and the volume of the positive electrode is changed. The solid electrolyte layer may be filled with the second electrolytic solution. “Even when the volume of the positive electrode changes” is a concept including the case where the volume of the positive electrode is not changed and the case where the volume of the positive electrode is changed in addition to the case where the volume of the positive electrode is changed. is there. “Filled with the second electrolytic solution” means that no gap is formed between the positive electrode and the solid electrolyte layer or no gap remains even when the volume of the positive electrode changes. It means that the space between the positive electrode and the solid electrolyte layer is filled with the first electrolytic solution. The electrolyte solution replenishment unit can have the same form as the electrolyte solution replenishment unit connected to the first electrolyte solution layer, except that the type of the electrolyte solution to be accommodated is appropriately selected.

  Furthermore, in the present invention, when the volume of the positive electrode or the negative electrode changes due to charging or discharging of the battery, a pressure applying unit that applies pressure so that no void is generated between the positive electrode or the negative electrode and the solid electrolyte layer is further provided. It is preferable to provide. Here, “applying pressure so as not to generate a gap between the positive electrode or negative electrode and the solid electrolyte layer” means, for example, applying pressure to the electrolyte replenishment section to allow the electrolyte to flow into the electrolyte layer. For example, it is possible to include a configuration that does not cause voids in the electrolyte layer by applying pressure to at least a part of the power generation unit. The “pressure applying unit” is not particularly limited as long as it is a unit capable of pressing at least a part of the power generation unit, and a known pressurizing device or the like can be used. Thereby, it can be set as a battery so that between an anode and a solid electrolyte layer may always be filled with electrolyte solution, and battery performance can be maintained.

  According to the present invention, since the space between the negative electrode and the solid electrolyte layer is always filled with the electrolyte even when the volume of the electrode, particularly the negative electrode is changed by charging or discharging the battery, It is possible to suppress a decrease in battery performance due to the generation of voids between the solid electrolyte layer.

1 is a diagram schematically showing a configuration of an air battery 100. FIG. 2 is a diagram schematically showing a configuration of an air battery 200. FIG. 2 is a diagram schematically showing a configuration of an air battery 300. FIG. 2 is a diagram schematically showing a configuration of an air battery 400. FIG.

  Hereinafter, the case where the present invention is applied to a lithium-based metal secondary battery, particularly a lithium-air battery will be mainly described.

1. First Embodiment FIG. 1 is a diagram schematically showing an air battery 100 according to a first embodiment. As shown in FIG. 1, the air battery 100 includes a positive electrode 10, a negative electrode 20, a solid electrolyte layer 30 interposed between the positive electrode 10 and the negative electrode 20, and a first electrolyte solution layer interposed between the negative electrode 20 and the solid electrolyte layer 30. 31, and a power generation unit 40 having a second electrolyte solution layer 32 interposed between the positive electrode 10 and the solid electrolyte layer 30, and a housing 50 containing them. In the power generation unit 40, the first electrolyte layer 31 and the second electrolyte layer 32 are separated by the solid electrolyte layer 30. A space is provided above the positive electrode 10 in the housing 50, and the oxygen layer 11 is provided on the surface of the positive electrode 10 by containing an oxygen-containing gas therein. From here, oxygen is taken in and used as a positive electrode active material, and is used for a battery reaction. On the other hand, an electrolyte solution replenishment unit 60 is connected to the first electrolyte solution layer 31 of the power generation unit 40 from the outside of the housing 50 so that the electrolyte solution can be replenished to the first electrolyte solution layer 31. In the air battery 100 according to the first embodiment, the stacked surface of each layer of the power generation unit 40 is a horizontal battery in which the layer is substantially the same as a horizontal plane. Hereinafter, each configuration of the air battery 100 will be described.

<Positive electrode 10>
The positive electrode 10 contains a conductive material, a catalyst, and a binder that binds these.

  The conductive material contained in the positive electrode 10 is not particularly limited as long as it can withstand the environment when the air battery 100 is used and has conductivity. Examples of the conductive material contained in the positive electrode 10 include carbon materials such as carbon black and mesoporous carbon. Further, from the viewpoint of suppressing a decrease in reaction field and a decrease in battery capacity, the content of the conductive material in the positive electrode 10 is preferably set to 10% by mass or more. Further, from the viewpoint of making the form capable of exhibiting a sufficient catalytic function, the content of the conductive material in the positive electrode 10 is preferably 99% by mass or less.

  Examples of the catalyst contained in the positive electrode 10 include cobalt phthalocyanine and manganese dioxide. From the standpoint of achieving a form capable of exhibiting a sufficient catalytic function, the content of the catalyst in the positive electrode 10 is preferably 1% by mass or more. Further, from the viewpoint of suppressing a decrease in reaction field and a decrease in battery capacity, the catalyst content in the positive electrode 10 is preferably 90% by mass or less.

  Examples of the binder contained in the positive electrode 10 include polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). The content of the binder in the positive electrode 10 is not particularly limited, but is preferably, for example, 10% by mass or less, and more preferably 1% by mass to 5% by mass.

  The positive electrode 10 can be produced, for example, by applying a paint composed of carbon black, a catalyst, and a binder to the surface of a positive electrode current collector described later by a doctor blade method. In addition, it can also be produced by hot pressing a mixed powder containing carbon black and a catalyst.

<Oxygen layer 11>
The oxygen layer 11 has a function of guiding oxygen gas present in the housing 50 to the positive electrode 10. The oxygen layer 11 is a passage of air guided to the positive electrode 10. For example, the oxygen layer 11 includes holes provided in the positive electrode current collector that contacts the inside or the outer surface of the positive electrode 10 and collects the current of the positive electrode 10. Function as. That is, the oxygen layer 11 can also be expressed as the positive electrode current collector 11.

  In the air battery 100, the positive electrode current collector has a function of collecting the positive electrode 10. In the air battery 100, the material of the positive electrode current collector is not particularly limited as long as it is a conductive material. Examples of the material for the positive electrode current collector include stainless steel, nickel, aluminum, iron, titanium, and carbon. Examples of the shape of the positive electrode current collector include a mesh (grid) shape.

<Negative electrode 20>
The negative electrode 20 contains a metal that functions as a negative electrode active material. In addition, the negative electrode 20 is provided with a negative electrode current collector (not shown) that contacts the inside or the outer surface of the negative electrode 20 and collects the negative electrode 20.

  Examples of the metal that can be contained in the negative electrode 20 include Li, Na, K, Mg, Ca, Al, Fe, Zn, and alloys thereof. From the viewpoint of providing the air battery 100 that can easily increase the capacity, it is preferable that Li is contained.

  The negative electrode 20 only needs to contain at least a negative electrode active material, and may further contain a conductive material that improves conductivity, or a binder that fixes the metal or the like. From the viewpoint of suppressing a decrease in reaction field and a decrease in battery capacity, the content of the conductive material in the negative electrode 20 is preferably 10% by mass or less. Further, the content of the binder in the negative electrode 20 is not particularly limited, but is preferably 10% by mass or less, and more preferably 1% by mass or more and 5% by mass or less. The type and amount of the conductive material and binder that can be contained in the negative electrode 20 can be the same as in the case of the positive electrode 10.

  In the air battery 100, a negative electrode current collector (not shown) is provided in contact with the inside or the outer surface of the negative electrode 20. The negative electrode current collector has a function of collecting the negative electrode 20. In the air battery 100, the material of the negative electrode current collector is not particularly limited as long as it is a conductive material. Examples of the material for the negative electrode current collector include copper, stainless steel, and nickel. Examples of the shape of the negative electrode current collector include a foil shape, a plate shape, and a mesh (grid) shape. In the air battery 100, the negative electrode 20 can be produced by the same method as that of the positive electrode 10, for example.

<Solid electrolyte layer 30>
The solid electrolyte layer 30 is a layer having a solid electrolyte that conducts ions between the positive electrode 10 and the negative electrode 20.

The solid electrolyte is not particularly limited as long as it is a solid electrolyte that can be used for the air battery 100. For example, when the air battery 100 is a lithium air battery, solid electrolytes applicable to lithium air batteries, such as various lithium-containing oxides and other lithium-based solid electrolytes, can be used. Specifically, a NASICON solid electrolyte such as Li _1.5 Ti ₂ Si _0.4 P _2.6 O ₁₂ and Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ , Li ₇ La Garnet type solid electrolytes such as ₃ Zr ₂ O ₁₂ and Li ₆ BaLa ₂ Ta ₂ O ₁₂ , perovskite type solid electrolytes such as Li _0.5 La _0.5 TiO ₃ , Li _3.6 P _0.4 Si _0.5 LISICON solid electrolytes such as O ₄ , Li _3.4 V _0.6 Ge _0.4 O ₄ , Li ₂ O—B ₂ O ₃ , LiCl—Li ₂ O—B ₂ O ₃ , Li ₂ O—SiO ₂ , and _{Li 2 SO 4 -LiPO 4, Li} 2 O-Nb 2 O 5, Li 2 O-Ta 2 O glass types such as ₅ solid electrolyte, polyethylene oxide, polyethylene oxide and ethyl glycidyl ether It can be used a solid polymer electrolyte such as a copolymer. The method for producing the solid electrolyte layer 30 is not particularly limited. For example, the solid electrolyte layer 30 can be produced by mixing a powdered solid electrolyte and performing pressure molding.

<First electrolyte layer 31>
The 1st electrolyte solution layer 31 is a layer which bears conduction of ion between the negative electrode 20 and the solid electrolyte layer 30, and is a layer containing electrolyte solution (1st electrolyte solution). The form of the electrolyte solution contained in the first electrolyte layer 31 is not particularly limited as long as it has metal ion conductivity, and an aqueous electrolyte solution or a non-aqueous electrolyte solution is selected depending on the metal used for the negative electrode. The In particular, a non-aqueous electrolyte is preferable. The type of the non-aqueous electrolyte is preferably selected as appropriate according to the type of metal ion to be conducted. For example, when the air battery 100 is a lithium-air battery, the non-aqueous electrolyte usually contains a lithium salt and a non-aqueous solvent.

Examples of the lithium salt contained in the first electrolyte layer 31 include imide salts such as LiTFSI and LiBETI, LiBF ₄ , LiPF ₆ , LiClO ₄ , LiBOB, and the like. Non-aqueous solvents include propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), butylene carbonate, γ-butyrolactone, sulfolane, acetonitrile, Cations such as 1,2-dimethoxymethane, 1,3-dimethoxypropane, diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and mixtures thereof, quaternary ammonium cations (chain, cyclic), imidazolium cations, pyridinium cations, etc. , TFSA anion, or BETA anion, FSA anion, BF ₄ anion, PF ₆ anion, the ionic liquids having the triflate anion, and anion such as ClO ₄ anion, a, _{C 6} Examples of the fluorine solvent include F ₁₄ , C ₇ F ₁₆ , C ₈ F ₁₈ , C ₉ F ₂₀ , hexafluorobenzene, and hydrofluoroether.

  Moreover, it is preferable that the 1st electrolyte solution layer 31 is set as the form by which the said electrolyte solution is hold | maintained at a separator or a gel polymer. Examples of the separator include porous membranes such as polyethylene and polypropylene, and nonwoven fabrics such as resin nonwoven fabrics and glass fiber nonwoven fabrics. Examples of the gel polymer include acrylate polymer compounds, ether polymer compounds such as polyethylene oxide, and crosslinked polymers containing these, methacrylate polymer compounds such as polymethacrylate, polyvinylidene fluoride, and polyvinylidene fluoride. Fluorine polymer compounds such as a copolymer of styrene and hexafluoropropylene can be used. The form of the gel polymer is not particularly limited as long as it is a form that can hold the electrolytic solution, such as a particulate form. The production of the first electrolyte layer 31 is not particularly limited, but the electrolyte solution is contained in an appropriately shaped separator or gel polymer filling layer, and the electrolyte solution is held in the separator or gel polymer. By doing so, the first electrolyte solution layer 31 having a predetermined shape is produced.

<Second electrolyte layer 32>
The 2nd electrolyte solution layer 32 is a layer which bears conduction of ion between the positive electrode 10 and the solid electrolyte layer 30, and is a layer containing electrolyte solution (2nd electrolyte solution). The form of the electrolytic solution contained in the second electrolytic solution layer 32 is not particularly limited as long as it has metal ion conductivity, and depending on the type of metal ions to be conducted, an aqueous electrolytic solution or a non-aqueous electrolytic solution is used. A liquid is appropriately selected. For example, when the air battery 100 is a lithium air battery, the electrolyte usually contains a lithium salt and an aqueous or non-aqueous solvent. Specific lithium salts and non-aqueous solvents that can be used for the first electrolyte layer 31 can be appropriately selected and used. Further, like the first electrolyte layer 31, the second electrolyte layer 32 is preferably in a form in which the electrolyte is held by a separator, a gel polymer, or the like. In the 1st electrolyte solution layer 31 and the 2nd electrolyte solution layer 32, the kind of electrolyte solution used may be the same and may differ.

<Power generation unit 40>
In the air battery 100, the power generation unit 40 is a laminate in which the positive electrode 10, the second electrolyte layer 32, the solid electrolyte layer 30, the first electrolyte layer 31, and the negative electrode 20 are laminated in this order. The method for laminating the positive electrode 10, the solid electrolyte layer 30, and the negative electrode 20 is not particularly limited. For example, a separator or gel polymer is disposed on both surfaces of the solid electrolyte layer 30, and the separator or gel polymer includes an electrolyte. Thus, the first electrolyte solution layer 31 and the second electrolyte solution layer 32 are formed on both surfaces of the solid electrolyte layer 30. And the electric power generation part 40 is produced by forming the positive electrode 10 in the 2nd electrolyte solution layer 32 surface, and forming the negative electrode 20 in the 1st electrolyte solution layer 31 surface.

<Case 50>
The housing 50 accommodates at least the power generation unit 40, the oxygen layer 11, and the oxygen-containing gas. In the air battery 100, the shape of the housing 50 is not particularly limited. For example, a part of the casing 50 may be meshed to take in an oxygen-containing gas such as air from the outside, and oxygen may be supplied to the positive electrode of the air battery 100. A form in which oxygen is supplied to the positive electrode of the air battery 100 after an oxygen-containing gas or the like is accommodated and sealed in advance may be used. As a constituent material of the casing 50, a material that can be used for the casing of the air battery can be appropriately used. The oxygen-containing gas taken in or accommodated in the housing 50 (existing in the space 51) is not particularly limited as long as it contains oxygen, but is preferably air, preferably dry air, An oxygen gas having a pressure of 1.01 × 10 ⁵ Pa and an oxygen concentration of 99.99% can be used.

<Electrolyte replenishment part 60>
The electrolytic solution replenishment unit 60 is a portion formed so that the first electrolytic solution layer 31 can be appropriately supplemented with an electrolytic solution. The form of the electrolyte solution replenishment unit 60 is not particularly limited as long as the electrolyte solution can be appropriately replenished in the first electrolyte layer 31. However, in the air battery 100, the electrolyte solution replenishment unit 60 is not limited. The tubular member is formed in a substantially L shape. The material of the tube is not particularly limited as long as it is stable with respect to the electrolytic solution and can appropriately accommodate the electrolytic solution. For example, a material similar to that of the housing 50 can be used. One end portion of the tube is inserted into the first electrolyte solution layer 31 inside the housing 50 from the outside of the housing 50 through, for example, a hole provided in the housing 50, so that the first electrolyte solution layer 31 is inserted. And the electrolyte replenisher 60 are in fluid communication. On the other hand, the other end of the electrolytic solution replenishing unit 60 is located above the upper surface of the first electrolytic solution layer 31. An electrolyte solution similar to the electrolyte solution used for the first electrolyte solution layer 31 is accommodated in the electrolyte solution replenishing unit 60. The electrolyte solution level in the electrolyte solution replenishment unit 60 is higher than that of the first electrolyte solution layer 31, and the electrolyte solution surface of the electrolyte solution replenishment unit 60 is configured to receive a predetermined pressure. For example, the electrolyte replenisher 60 is hermetically sealed, and an inert gas (Ar, N _2, etc.) having a predetermined pressure is present above the electrolyte surface so that a predetermined pressure is applied to the electrolyte surface. Can do. The pressure is not particularly limited as long as the electrolyte can be appropriately replenished from the electrolyte replenisher 60 to the first electrolyte layer 31. For example, the pressure can be a pressure equal to or higher than the atmospheric pressure. On the other hand, the electrolytic solution replenishing unit 60 may be opened so that atmospheric pressure is applied to the electrolytic solution surface. However, from the viewpoint of preventing deterioration of the electrolytic solution and preventing adverse effects on the inside of the battery (particularly the negative electrode), it is preferable that the electrolytic solution replenishing unit 60 is sealed and an inert gas is present inside.

  In the air battery 100, metal ions are exchanged between the negative electrode 20 and the first electrolyte layer 31 as the battery is charged and discharged, and the volume of the negative electrode 20 changes. In the conventional air battery, when the volume of the negative electrode changes, the liquid level of the electrolyte contained in the first electrolyte layer 31 rises and falls, and a gap is generated between the negative electrode 20 and the solid electrolyte layer 30, thereby improving battery performance. There were cases where it had an adverse effect. On the other hand, in the air battery 100, the electrolyte replenishment unit 60 is connected to the first electrolyte solution layer 30, and the electrolyte solution surface of the electrolyte solution replenishment unit 60 is positioned above the first electrolyte solution layer 30. In addition, since atmospheric pressure is applied, even when a void is generated between the negative electrode 20 and the solid electrolyte layer 30 due to a change in volume of the negative electrode 20, the electrolytic solution is automatically generated in the void portion. Flows into the gap (the gap moves to the electrolyte replenishment unit 60), and the space between the negative electrode 20 and the solid electrolyte layer 30 is always filled with the electrolyte. Therefore, it can suppress that battery performance falls by the space | gap which arises with the volume change of the negative electrode 20. FIG.

  Even when the volume of the negative electrode 20 is the smallest under the use conditions of the air battery 100 and the amount of the electrolytic solution in the first electrolytic solution layer 31 is maximized, the electrolytic solution level in the electrolytic solution replenishing unit 60 is the first. It is preferable to be located above one electrolyte layer 31. Therefore, it is preferable that the volume of the electrolyte replenishment unit 60 is larger than the volume reduction amount of the negative electrode 20, and the electrolyte solution replenishment unit 60 can accommodate more electrolyte solution than the volume reduction amount of the negative electrode 20.

3. Second Embodiment FIG. 2 is a diagram schematically showing an air battery 200 according to a second embodiment. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 2, the air battery 200 includes a positive electrode 10, a negative electrode 20, a solid electrolyte layer 30 interposed between the positive electrode 10 and the negative electrode 20, and a first electrolyte solution interposed between the negative electrode 20 and the solid electrolyte layer 30. The power generation part 40 which has the layer 31 and the 2nd electrolyte solution layer 32 interposed between the positive electrode 10 and the solid electrolyte layer 30, and the housing | casing 50 which includes these are provided. In the power generation unit 40, the first electrolyte layer 31 and the second electrolyte layer 32 are separated by the solid electrolyte layer 30. The shape of the casing 50 is not particularly limited, as in the case of the air battery 100. Other than the form in which oxygen-containing gas can be taken in from the outside, for example, by forming a part of the casing 50 into a mesh shape. The casing 50 can be hermetically sealed and the oxygen-containing gas can be present in the space 51. Thereby, the oxygen layer 11 is provided on the surface of the positive electrode 10, and oxygen is taken in from this and used as the positive electrode active material, thereby causing a battery reaction. On the other hand, an electrolyte replenishment unit 160 is connected to the first electrolyte solution layer 31 of the power generation unit 40 from the outside of the housing 50 so that the electrolyte solution can be replenished to the first electrolyte solution layer 31. In the air battery 200 according to the second embodiment, the stacked surface of each layer of the power generation unit 40 is a vertical battery in which the vertical surface is substantially the same. That is, the air battery 200 is different from the air battery 100 in that the battery is a vertical type and includes an electrolyte replenisher 160 instead of the electrolyte replenisher 60.

<Electrolyte replenisher 160>
The electrolyte replenishment unit 160 is a part that is connected to the first electrolyte layer 31 and appropriately replenishes the first electrolyte layer 31 with the electrolyte. The form of the electrolytic solution replenishment unit 160 is not particularly limited as long as the electrolytic solution can be appropriately supplemented to the first electrolytic solution layer 31. However, the air battery 200 can accommodate the electrolytic solution. It is a tubular member. The material of the tube is not particularly limited as long as it is stable with respect to the electrolytic solution and can appropriately accommodate the electrolytic solution. For example, a material similar to that of the housing 50 can be used. One end of the tube is inserted into the first electrolyte solution layer 31 from the outside of the housing 50 through, for example, a hole provided in the housing 50, whereby the first electrolyte solution layer 31 and the electrolyte solution replenishment unit 160 is in fluid communication. On the other hand, the other end of the electrolyte solution replenishment unit 160 is located above the first electrolyte solution layer 31. An electrolyte solution similar to the electrolyte solution used for the first electrolyte layer 31 is accommodated in the electrolyte solution replenishment unit 160. Also in the electrolyte replenishment unit 160, as in the electrolyte solution replenishment unit 60, the liquid level of the electrolyte solution in the electrolyte solution replenishment unit 160 is located above the first electrolyte solution layer 31, and the electrolyte solution replenishment unit The electrolyte solution surface 160 is configured to receive a predetermined pressure. That is, the electrolyte replenishment unit 160 may be a sealed system and may have a form in which an inert gas having a predetermined pressure is contained therein or a form opened to the atmosphere. Further, as in the case of the air battery 100, the volume of the negative electrode 20 is the smallest under the battery usage conditions, and the electrolyte solution replenishment unit 160 has a maximum amount of electrolyte solution in the first electrolyte solution layer 31. It is preferable that the electrolytic solution surface is located above the first electrolytic solution layer 31 (that is, the excess electrolytic solution remains above the first electrolytic solution layer 31). Therefore, it is preferable that the volume of the electrolyte replenishment unit 160 is larger than the volume decrease of the negative electrode 20, and more electrolyte solution is accommodated in the electrolyte solution replenishment unit 60 than the volume decrease of the negative electrode 20.

  Also in such an air battery 200, when a void is generated between the negative electrode 20 and the solid electrolyte layer 30 due to a change in the volume of the negative electrode 20, the electrolyte automatically flows into the void (the void is replenished with the electrolyte). And the space between the negative electrode 20 and the solid electrolyte layer 30 is always filled with the electrolytic solution. Therefore, it can suppress that battery performance falls by the space | gap which arises with the volume change of the negative electrode 20. FIG.

3. Other Embodiments In the first embodiment and the second embodiment described above, the air batteries 100 and 200 provided with only one power generation unit 40 have been described. However, the present invention is not limited to this embodiment. It is good also as a stack-like air battery, such as a form in which a plurality of power generation units 40 are stacked or a form in which a plurality of power generation units 40 are separately provided in the casing 50. Even in this case. .. Are connected to the first electrolyte layers 31, 31,... Of the power generation units 40, 40,... (Or the electrolyte replenishers 160, 160,. ... and the solid electrolyte layers 30, 30, ... are always filled with an electrolyte, thereby suppressing the internal resistance from increasing due to the voids caused by the volume change of the negative electrodes 20, 20, ..., and reducing the battery performance. it can.

  Moreover, in the said 1st Embodiment and 2nd Embodiment, although demonstrated as what accommodates the electric power generation part 40 which is a laminated body on which the substantially planar layer was laminated | stacked in the housing | casing 50 as it is, this invention. Is not limited to this form. For example, the power generation unit formed in a cylindrical shape by combining one end and the other end of the power generation unit 40 may be accommodated in the housing 50.

  Moreover, in the said 1st Embodiment and 2nd Embodiment, although the form with which the 2nd electrolyte solution layer 32 was provided in the electric power generation part 40 was demonstrated, this invention is not limited to this form. In the present invention, the second electrolytic solution layer 32 is not necessarily required, and the second electrolytic solution layer 32 may not be provided.

  Moreover, in the said 1st Embodiment and 2nd Embodiment, although the form in which the space 51 and the oxygen layer 11 were provided in the housing 50 was illustrated, this invention is not limited to this form. For example, by providing a hole or the like in the housing 50 and taking in an oxygen-containing gas from the outside, the hole may function as an oxygen layer.

  On the other hand, in the first embodiment and the second embodiment in which the first electrolytic solution layer 31 and the second electrolytic solution layer 32 are provided in the power generation unit 40, the electrolytic solution supplementing unit 60 or 160 is provided only in the first electrolytic solution layer 31. For example, as shown in FIG. 3, the metal secondary battery in which the electrolyte replenishment unit 60 ′ having the same configuration as the electrolyte replenishment unit 60 is connected to the second electrolyte layer 32 as shown in FIG. 3. It can also be 300. Further, in the case where the battery is of a vertical type and has an electrolyte replenishment unit 160 instead of the electrolyte replenishment unit 60 as in the metal secondary battery 200, as shown in FIG. The electrolyte replenishing unit 160 ′ having the same form as that of 160 may be the metal secondary battery 400 connected to the second electrolyte layer 32. In the metal secondary battery 300 or 400, the electrolyte replenisher 60 'or 160' contains the same electrolyte as that contained in the second electrolyte layer. The liquid level of the electrolytic solution in the electrolytic solution replenishing units 60 ′ and 160 ′ is higher than the second electrolytic solution layer 32, and the electrolytic solution level in the electrolytic solution replenishing units 60 ′ and 160 ′ is Under atmospheric pressure. As a result, even when the volume of the positive electrode 10 changes as the battery is charged and discharged, the space between the positive electrode 10 and the solid electrolyte layer 30 is always filled with the second electrolyte layer 32. It can suppress that battery performance falls by the space | gap which arises with the volume change of the positive electrode 10. FIG.

  In addition to or in addition to the above, a pressure applying means (not shown) capable of applying pressure to the electrolyte replenishment unit 60 and the power generation unit 40 may be provided in accordance with the volume change of the electrode. The position where the pressure applying means is provided is not particularly limited. Also, the pressure applied by the pressure applying means is not particularly limited as long as it does not cause excessive pressure in the battery. Furthermore, it can also be set as the form controlled so that a pressure can be provided based on the volume change of the electrode derived | led-out from the discharge amount etc. of the battery using a control apparatus together.

For example, in the above description, electrolysis of the electrolyte solution replenishment unit 60, 160, 60 ′ or 160 ′ (hereinafter simply referred to as “electrolyte replenishment unit”) that has been subjected to a predetermined pressure by an inert gas or air. It can be configured such that pressure can be applied to the liquid surface by pressure applying means. In this case, for example, pressure application that can apply a pressure of 1.01 × 10 ⁵ N / m ² or more and 2.03 × 10 ⁵ N / m ² or less (1 atm to ² atm) to the electrolyte surface in the electrolyte replenishment unit. It is preferable to use a means. When the battery (housing 50) is a closed system, the internal pressure of the battery is set to about 1.01 × 10 ⁵ N / m ² or more and 2.03 × 10 ⁵ N / m ² or less (1 atm to ² atm) in advance. It is also possible to adjust the pressure. According to this embodiment, the electrolytic solution in the electrolytic solution replenishment part can be easily flown into the first electrolytic solution layer 31 or the second electrolytic solution layer 32, and the electrode (positive electrode 10 or negative electrode 20) and the solid electrolyte layer 30 can be made. Can be always filled with the electrolyte layer. In addition, a pressure applying unit is provided between the negative electrode 20 and the casing 50 or between the positive electrode 10 and the casing 50 to apply pressure in a direction substantially the same as the stacking direction of the power generation unit 40. You can also. In this case as well, as described above, a pressure capable of applying a pressure of 1.01 × 10 ⁵ N / m ² or more and 2.03 × 10 ⁵ N / m ² or less (1 atm to ² atm) to the power generation unit 40 when the battery is discharged. It is preferable to use the applying means. Even with this configuration, the gap generated between the electrode and the solid electrolyte layer 30 can be easily and quickly escaped to the outside, and no gap is generated between the electrode and the solid electrolyte layer 30.

Moreover, in the said 1st Embodiment and 2nd Embodiment, although demonstrated that this invention was applied to an air battery, this invention is a metal secondary battery which uses together a solid electrolyte and electrolyte solution as electrolyte. In addition, the present invention can be applied without particular limitation as long as there is a possibility that a change in volume of the electrode occurs due to charging and discharging of the battery and a gap may be generated between the solid electrolyte layer and the electrolyte layer. For example, a lithium ion secondary battery including a layered oxide such as LiCoO ₂ or LiNiO ₂ or a sulfur-based positive electrode material containing S may be used for the positive electrode. In this case, it is not necessary to store the oxygen-containing gas in the housing 50, and it is not necessary to provide the space 51 between the positive electrode 10 and the inner wall of the housing 50.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the invention is not limited to the embodiments disclosed herein. However, the present invention can be modified as appropriate without departing from the spirit or concept of the invention which can be read from the claims and the entire specification, and is understood to be included in the technical scope of the present invention. It must be.

  The present invention can be suitably used as a power source for portable devices, electric vehicles, hybrid vehicles, and the like.

DESCRIPTION OF SYMBOLS 10 Positive electrode 20 Negative electrode 30 Solid electrolyte layer 31 1st electrolyte layer 32 2nd electrolyte layer 40 Power generation part 50 Case 60 Electrolyte replenishment part 100 Metal secondary battery 160 Electrolyte replenishment part 200 Metal secondary battery 300 Metal secondary Battery 400 Metal secondary battery

Claims (4)

The power generation unit includes a positive electrode, a solid electrolyte layer, a first electrolyte layer, and a negative electrode in this order. The first electrolyte layer includes a first electrolyte , and the first electrolyte layer includes an electrolyte solution. A replenishment part is connected, and the liquid level of the electrolyte contained in the electrolyte replenishment part is higher than the position of the first electrolyte layer,
The first electrolyte layer and the electrolyte replenishment unit are always in fluid communication,
When the volume of the negative electrode changes, the first electrolytic solution is replenished from the electrolytic solution replenishment unit to the first electrolytic solution layer by the amount of the negative electrode volume change, or from the first electrolytic solution layer Even when the volume of the negative electrode changes due to the movement of the first electrolytic solution to the electrolytic solution replenishment section, the space between the solid electrolyte layer and the negative electrode is filled with the first electrolytic solution. , Metal secondary battery. The metal secondary battery according to claim 1, further comprising a second electrolyte solution layer containing a second electrolyte solution between the positive electrode and the solid electrolyte layer. An electrolyte replenisher is connected to the second electrolyte layer, and the space between the positive electrode and the solid electrolyte layer is filled with the second electrolyte even when the volume of the positive electrode changes. Item 3. A metal secondary battery according to Item 2 . When a volume of the positive electrode or the negative electrode is changed by charging or discharging a battery, a pressure applying unit is provided that applies pressure so that no void is generated between the positive electrode or the negative electrode and the solid electrolyte layer. The metal secondary battery in any one of Claims 1-3 .

Images