JP5625344B2 - Air battery conditioning method and air battery manufacturing method - Google Patents

Description

  The present invention relates to an air battery conditioning method and an air battery manufacturing method.

  In recent years, from the viewpoint of protecting the global environment, a high-performance secondary battery is required to be applied to an electric vehicle or a hybrid vehicle as a low-pollution vehicle.

  In order to improve and improve the performance of the secondary battery, it is effective to condition the battery at the time of manufacturing or using the battery. For example, as described in Patent Document 1, in the case of a secondary battery using a liquid electrolyte, in order to improve the liquid wettability of the electrode layer and increase the battery capacity, The battery can be conditioned by repeating several cycles of charging and discharging. In general, the charge / discharge rate for battery conditioning is lower than when the battery is used. This is because when charging / discharging was performed at a high rate, liquid wetting was uneven and it was considered undesirable.

  On the other hand, among the secondary batteries, the air battery is a battery that uses oxygen as an air electrode active material, and takes in air from the outside during discharge. Therefore, other batteries having an air electrode and a negative electrode active material in the battery are used. In comparison with this, it is possible to increase the proportion of the negative electrode active material in the battery container. Therefore, in principle, the electric capacity that can be discharged is large, and it is easy to reduce the size and weight. Further, since the oxidizing power of oxygen used as the air electrode active material is strong, the battery electromotive force is relatively high. Furthermore, since oxygen has a feature that it is a clean material without resource restrictions, the air battery has a small environmental load. It is considered that the battery performance can be further improved by conditioning the battery of the air battery having such many advantages.

JP 2004-342520 A

  The present inventors performed conditioning of an air battery using a conventional conditioning method as described in Patent Document 1. However, in the charging / discharging process of the air battery, the generation and disappearance of the solid oxide are accompanied. Therefore, as described in Patent Document 1, the charging / discharging is simply performed for several cycles to improve the wettability of the electrode layer with respect to the electrolytic solution. However, the battery performance could not be improved only by the use. This is because in an air battery, rather than the wettability of the electrode layer, the increase in the reaction starting point in the electrode layer and the promotion of oxygen around the reaction starting point are important factors for improving battery performance. It was. In particular, when a conventional conditioning method is used in a lithium-air secondary battery, the size of a product during discharge (hereinafter referred to as a discharge product) increases, so that the discharge product is not decomposed during charging. We faced the problem that the nucleation growth mode is larger than the nucleation and the Coulomb efficiency (charge capacity / discharge capacity) becomes very low. In particular, when the discharge product, which is an insulator, covers the electrode surface, a path for electron conduction and oxygen / lithium ion diffusion cannot be formed at all, and the charge / discharge cycle cannot be repeated thereafter.

  This invention is made | formed in view of the above, and makes it a subject to provide the conditioning method of an air battery and the manufacturing method of an air battery in order to obtain an air battery with high coulomb efficiency.

In order to solve the above problems, the present invention has the following configuration. That is,
1st this invention is the conditioning method of an air battery which charges / discharges an air battery at a high rate compared with the charge / discharge rate at the time of normal use.

In the first aspect of the present invention and the present invention described below, “in normal use” refers to a case where the air battery is charged / discharged at a rate set in advance so as to be suitable for a predetermined application. The predetermined application is not particularly limited from a large power source such as an in-vehicle power source to a small power source such as a mobile phone power source. Specific examples of the “rate” or “charge / discharge rate” include current density (mA / cm ² ) during charge / discharge. “Charging and discharging air batteries at a higher rate than in normal use” means that the charge / discharge rate is relatively higher than the charge / discharge rate set in advance to be suitable for a given application. This means that the air battery is charged and discharged.

  In the first aspect of the present invention, when the capacity of the air battery during normal use is below a predetermined value, the air battery is charged and discharged at a higher rate than the charge / discharge rate during normal use. Conditioning is preferably performed. By doing in this way, even if it is a case where the capacity | capacitance of an air battery falls, a capacity | capacitance can be recovered by conditioning.

  In the first aspect of the present invention, it is preferable that the air battery is charged and discharged and the battery is conditioned while maintaining the temperature of the air battery at a temperature higher than that during normal use. By doing in this way, penetration of the electrolyte solution in an electrode layer can be promoted, a reaction field can be increased, and battery performance can be improved.

  The second aspect of the present invention is to produce a power generation unit having an air electrode, an electrolyte, and a negative electrode, and to charge and discharge the power generation unit at a higher rate than the power generation unit production process and the charge / discharge rate during normal use. It is a manufacturing method of an air battery which has a conditioning process.

  In the conditioning process according to the second aspect of the present invention, it is preferable to charge and discharge the power generation unit while maintaining the temperature of the power generation unit at a higher temperature than that during normal use. By doing in this way, the penetration of the electrolyte solution in the electrode layer can be promoted, the reaction field can be increased, and an air battery with better performance can be manufactured.

According to the first aspect of the present invention, during battery conditioning, the air battery is charged and discharged at a higher rate than during normal use. When discharging at a high rate, discharge products with small dimensions are uniformly deposited, but the discharge products do not block the path for electron conduction and oxygen / lithium ion diffusion, and the electrolyte solution to the electrode layer Penetration can be promoted and the cell reaction field can be increased. In addition, when charging at a high rate, the minute discharge products generated by the high rate discharge can be efficiently decomposed, so that the remaining discharge products can be reduced. Further, along with the decomposition reaction of the discharge product (for example, Li ₂ O ₂ → 2Li ⁺ + O ₂ ↑ + 2e ⁻ ), oxygen supply can be promoted to the inside of the electrode layer, and the effective surface area related to the battery reaction is increased. Can be made. Thus, according to the first aspect of the present invention, it is possible to provide a conditioning method for an air battery that can increase the reaction field, promote oxygen supply, and provide a battery having excellent coulomb efficiency. it can.

  According to the second aspect of the present invention, the air battery is manufactured after conditioning the power generation unit by the conditioning method according to the first aspect of the present invention. Therefore, the reaction field is increased, oxygen supply is promoted, and an air battery excellent in coulomb efficiency can be manufactured.

3 is a flowchart for explaining a method of conditioning an air battery according to an embodiment of the present invention. It is a flowchart for demonstrating the manufacturing method of the air battery of this invention which concerns on one Embodiment. It is a figure for demonstrating one form of the air battery which can apply this invention. It is a figure which shows a battery characteristic in the case of conditioning an air battery by the conventional method. It is a figure which shows the battery characteristic at the time of conditioning an air battery by the method which concerns on a reference example. It is a figure which shows the battery characteristic at the time of conditioning an air battery by the method which concerns on an Example.

  Hereinafter, the case where the present invention is applied to a lithium-air battery will be mainly described. However, the present invention is not limited to this form, and can be applied to other air batteries.

1. Air Battery Conditioning Method FIG. 1 is a flowchart for explaining an air battery conditioning method S10 (hereinafter simply referred to as “method S10”) according to an embodiment of the present invention. As shown in FIG. 1, the method S10 includes a step S1 of charging and discharging at a predetermined rate during normal use, a step S2 of checking the battery capacity and checking whether the battery capacity is greater than a predetermined value, When a negative determination (battery capacity is equal to or less than a predetermined value) is made in step S2, step S3 performs charging / discharging at a higher rate than the charge / discharge rate during normal use, and an affirmative determination (battery capacity) Step S4 for continuing charging / discharging at a predetermined rate during normal use. Hereinafter, each process will be described.

(Process S1)
Step S1 is a step of operating the air battery in a predetermined application by charging and discharging at a preset rate for normal use. The charge / discharge rate during normal use is not particularly limited, and may be appropriately selected depending on the use of the battery, the connection form of the battery, and the like.

(Process S2)
Step S2 is a step of confirming the capacity (for example, discharge capacity) of the air battery and determining whether or not the capacity is larger than a predetermined value. The capacity of the air battery can be confirmed by a known means electrically connected to the air battery. For example, it can be confirmed by performing a known charge / discharge test. Regarding the capacity, when the capacity of the air battery in the initial state (for example, at the time of shipment) is 100%, an arbitrary capacity of about 50 to 80% can be set as the predetermined value.

(Process S3)
Step S3 is a step of performing charge / discharge at a rate higher than the charge / discharge rate according to step S1 when a negative determination (battery capacity is equal to or less than a predetermined value) is made in step S2. In step S3, the battery is conditioned so that the capacity of the air battery becomes larger than a predetermined value. As a charging / discharging rate which concerns on process S3, it can be set as a high rate about 2 to 5 times with respect to the charging / discharging rate which concerns on process S1, for example. In process S3, it controls so that a charge / discharge cycle may be repeated 2-50 times, for example. Alternatively, the charge / discharge cycle may be repeated for a predetermined time. In step S3, charge and discharge are performed at a higher rate than in normal use, so that discharge products with small dimensions are uniformly deposited in the air battery. Does not block the path for ion diffusion. And in an air battery, electrolyte solution osmosis | permeation to an electrode layer can be accelerated | stimulated and a battery reaction field can be increased. In addition, when charging at a higher rate than during normal use, the minute discharge products generated by the high rate discharge can be efficiently decomposed, so that the remaining discharge products can be reduced. Further, along with the decomposition reaction of the discharge product (for example, Li ₂ O ₂ → 2Li ⁺ + O ₂ ↑ + 2e ⁻ ), oxygen supply can be promoted to the inside of the electrode layer, and the effective surface area related to the battery reaction is increased. Can be made. According to step S3, the air battery is conditioned in this way, and the air battery performance can be improved so that the battery capacity becomes larger than a predetermined value.

  When a highly viscous solvent is used for the electrolyte of the air battery, the electrode (particularly the porous air electrode) has poor wettability, and the charge / discharge reaction field is not sufficiently formed. May not be possible. Therefore, in step S3, it is preferable that high rate charge / discharge be performed while maintaining the temperature of the air battery at a higher temperature than during normal use. By doing in this way, the viscosity of electrolyte solution can be reduced and the circumference | surroundings of the liquid to an electrode can be improved. Specifically, when a lithium air battery is used as the air battery, it is preferable to perform step S3 while maintaining the temperature at about 45 to 100 ° C.

(Process S4)
On the other hand, if an affirmative determination (the battery capacity is greater than the predetermined value) is made in step S2, the air battery maintains a necessary and sufficient capacity during normal use. Therefore, it is not necessary to condition the air battery, and charging / discharging may be performed as it is at a rate during normal use.

  Thus, method S10 has process S1-S4 (especially process S3). Through the steps S1 to S4, the battery capacity of the air battery is appropriately maintained and improved, and sufficient battery performance can be always obtained during normal use. In particular, since the air battery is appropriately conditioned by the step S3, according to the method S10, the reaction field can be increased, the oxygen supply can be promoted, and a battery having excellent coulomb efficiency can be obtained. It can be set as the conditioning method of an air battery.

  In the method S10 described above, the step S3 is performed after the step S2 for determining whether the capacity of the air battery is larger than a predetermined value. However, the step S2 is not essential in the present invention. The conditioning method according to the present invention may be in a form in which charging / discharging is performed at a higher rate than the charging / discharging rate during normal use. For example, the conditioning method is normally used in step S1, and every predetermined time and period. The form which can be switched to the high rate charging / discharging by process S3 may be sufficient.

2. Air Battery Manufacturing Method In the method S10 described above, the conditioning method according to the present invention has been described as being applied during normal use of an air battery. However, the air battery conditioning method according to the present invention is also applicable as a conditioning method during battery manufacture. FIG. 2 is a flowchart for explaining an air battery manufacturing method S20 (hereinafter simply referred to as “manufacturing method S20”) according to the present invention. As shown in FIG. 2, the manufacturing method S20 includes at least a step S11 for producing a power generation unit, and a charge / discharge rate during normal use of the power generation unit (assumed to be used for a predetermined application after battery manufacture). And step S12 of performing conditioning by charging / discharging at a higher rate than the set charging / discharging rate).

(Process S11)
Step S11 is a step of producing a power generation unit that charges and discharges the air battery. A power generation part will not be specifically limited if it is a form which can function as a power generation part of an air battery. For example, an air electrode and an oxygen layer in contact with the air electrode, a negative electrode, and a layer containing an electrolyte provided between the air electrode and the negative electrode, and optionally a power generation unit further including a current collector or the like. it can. The power generation unit is housed in the housing, and is an air battery after performing step S12 described below.

(Process S12)
Step S12 is a step of charging / discharging the power generation unit produced in step S11 at a higher rate than the charge / discharge rate during normal use. In step S12, the power generation unit is conditioned. As the charge / discharge rate according to step S12, after the air battery is manufactured, charge / discharge is performed at a high rate of about 2 to 5 times the charge / discharge rate set in advance for use in a predetermined application. In step S12, for example, the charge / discharge cycle is controlled to be repeated 2 to 50 times. Alternatively, the charge / discharge cycle may be repeated for a predetermined time. In step S12, by performing charge / discharge at a rate higher than the charge / discharge rate during normal use assumed after manufacture, a small-sized discharge product is uniformly deposited on the power generation unit. The product does not block the path for electron conduction and oxygen / lithium ion diffusion. And in an electric power generation part, electrolyte solution osmosis | permeation to an electrode layer (air electrode, negative electrode) can be accelerated | stimulated, and a battery reaction field can be increased. In addition, when charging at a higher rate than during normal use, the minute discharge products generated by the high rate discharge can be efficiently decomposed, so that the remaining discharge products can be reduced. Further, along with the decomposition reaction of the discharge product (for example, Li ₂ O ₂ → 2Li ⁺ + O ₂ ↑ + 2e ⁻ ), oxygen supply can be promoted to the inside of the electrode layer, and the effective surface area related to the battery reaction is increased. Can be made. As described above, when the battery is manufactured, the air battery with the battery performance increased can be manufactured by performing the process S12 appropriately as compared with the case where the conditioning of the power generation unit is appropriately performed and the conditioning is not performed. In addition, when a highly viscous solvent is used for the electrolyte, the electrode (particularly the porous air electrode) has poor wettability, and the charge / discharge reaction field is not sufficiently formed, so that a sufficiently large charge / discharge capacity can be obtained. There are cases where it is impossible. Therefore, in step S12, it is preferable that high rate charge / discharge be performed while maintaining the temperature of the power generation unit at a higher temperature than during normal use. By doing in this way, the viscosity of electrolyte solution can be reduced, the circumference | surroundings of the liquid to an electrode can be improved, and a more efficient air battery can be manufactured. Specifically, when producing a lithium air battery, it is preferable to perform process S12, hold | maintaining at the temperature of about 45-100 degreeC.

  Thus, manufacturing method S20 produces an electric power generation part by process S11, and after the conditioning of an electric power generation part is appropriately performed by process S12, an air battery is manufactured. By passing through steps S11 and S12, the reaction field can be increased, oxygen supply can be promoted, and an air battery excellent in coulomb efficiency can be manufactured.

  The air battery conditioning method (method S10) or the air battery manufacturing method (manufacturing method S20) according to the present invention can be applied to a known air battery or a known air battery manufacturing process. For example, as shown in FIG. 3, power generation having an air electrode 11 and an oxygen layer 12, a negative electrode 13, and a layer 14 (electrolyte layer 14) containing an electrolyte provided between the air electrode 11 and the negative electrode 13. The method S10 can be applied to the air battery 10 in which the unit 15 is accommodated in the housing 16, or the manufacturing method S20 can be applied when the air battery 10 is manufactured. The details of the air battery 10 are as follows, for example. However, the air battery that can be applied to the present invention is not limited to the illustrated form, and a form in which a plurality of power generation units are accommodated in a housing, a form in which a power generation unit is wound, or a plurality of air cells are stacked. Various forms are possible, such as different forms.

(Air electrode 11)
The air electrode 11 contains a conductive material, a catalyst, and a binder for binding them.

  The conductive material contained in the air electrode 11 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 air electrode 11 include carbon materials such as carbon black, ketjen 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 air electrode 11 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 air electrode 11 is preferably 99% by mass or less.

  Examples of the catalyst contained in the air electrode 11 include cobalt phthalocyanine and manganese dioxide. From the viewpoint of providing a form capable of exhibiting a sufficient catalytic function, the content of the catalyst in the air electrode 11 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 content of the catalyst in the air electrode 11 is preferably 90% by mass or less.

  Examples of the binder contained in the air electrode 11 include polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). The content of the binder in the air electrode 11 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 air electrode 11 can be produced, for example, by applying a paint made of carbon black, a catalyst, and a binder to the surface of an air 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 12)
The oxygen layer 12 has a function of guiding oxygen gas present in the housing 16 to the air electrode 11. The oxygen layer 12 is a passage of air led to the air electrode 11. For example, a hole provided in a current collector that collects the air electrode 11 in contact with the inside or the outer surface of the air electrode 11 has oxygen Functions as layer 12. That is, the oxygen layer 12 can also be expressed as the air electrode current collector 12.

  In the air battery 10, the air electrode current collector has a function of collecting the air electrode 11. In the air battery 10, the material of the air electrode current collector is not particularly limited as long as it is a conductive material. Examples of the material for the air electrode current collector include stainless steel, nickel, aluminum, iron, titanium, and carbon. Examples of the shape of such an air electrode current collector include a mesh (grid) shape.

(Negative electrode 13)
The negative electrode 13 contains a metal that functions as a negative electrode active material. The negative electrode 13 is optionally provided with a negative electrode current collector (not shown) that contacts the inside or the outer surface of the negative electrode 13 and collects the negative electrode 13.

  Examples of the metal that can be contained in the negative electrode 13 include Li, Na, K, Al, Mg, Ca, Zn, and Fe, and alloys thereof. From the viewpoint of providing the air battery 10 that can easily increase the capacity, it is preferable that Li is contained.

  The negative electrode 13 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 13 is preferably 10% by mass or less. Further, the content of the binder in the negative electrode 13 is not particularly limited, but is preferably, for example, 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 13 can be the same as in the case of the air electrode 11.

  In the air battery 10, a negative electrode current collector (not shown) may be provided in contact with the inside or the outer surface of the negative electrode 13. The negative electrode current collector has a function of collecting the negative electrode 13. In the air battery 10, the material for 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 10, the negative electrode 13 can be produced by the same method as that for the air electrode 11, for example.

(Electrolyte layer 14)
The electrolyte layer 14 is a layer having an electrolyte that conducts ions between the air electrode 11 and the negative electrode 13. As the electrolyte, a liquid or solid electrolyte can be used without any particular limitation.

  When the electrolytic solution is used as the electrolyte, it is not particularly limited as long as it has metal ion conductivity, and an aqueous electrolytic solution or a non-aqueous electrolytic solution is selected depending on the metal used for the negative electrode. 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 10 is a lithium-air battery, the non-aqueous electrolyte usually contains a lithium salt and a non-aqueous solvent.

As the lithium salt contained in the electrolytic solution, imide salts such as LiTFSI and LiBETI, LiBF ₄ , LiPF ₆ , LiClO ₄ , LiBOB and the like can be used. 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, when using electrolyte solution as electrolyte, it is preferable to set it as the form by which 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 electrolyte layer 14 related to the electrolytic solution is not particularly limited, but the electrolyte solution is contained in a suitably shaped separator or gel polymer filled layer, and the electrolytic solution is added to the separator or gel polymer. By holding, the electrolyte layer 14 having a predetermined shape is produced.

When a solid electrolyte is used for the electrolyte layer 14, the solid electrolyte is not particularly limited as long as it is a solid electrolyte that can be used for the air battery 10. For example, when the air battery 10 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 electrolyte layer 14 relating to the solid electrolyte is not particularly limited, and for example, it can be produced by mixing a powdered solid electrolyte and performing pressure molding.

(Power generation unit 15)
In the air battery 10, the power generation unit 15 is a stacked body in which the above (oxygen layer 12), the air electrode 11, the electrolyte layer 14, and the negative electrode 13 are stacked in this order. The method for laminating the air electrode 11, the electrolyte layer 14, and the negative electrode 13 is not particularly limited, and a separator or gel polymer is disposed between the air electrode 11 and the negative electrode 13, and an electrolyte solution is included in the separator or gel polymer. Thus, a mode in which an electrolyte layer 14 relating to an electrolytic solution is provided between the air electrode 11 and the negative electrode 13, or an electrolyte layer 14 relating to a pressure-molded solid electrolyte is provided between the air electrode 11 and the negative electrode 13. The form etc. to arrange | position can be illustrated.

(Case 16)
The housing 16 accommodates at least the power generation unit 40, the oxygen layer 12, and the oxygen-containing gas. In the air battery 10, the shape of the housing 16 is not particularly limited. For example, in a form in which oxygen is supplied to the air electrode of the air battery 10 by taking in an oxygen-containing gas such as air from the outside by forming a part of the casing 16 in a mesh shape or providing a supply port. There may be a configuration in which oxygen is supplied to the air electrode of the air battery 10 after the oxygen containing gas or the like is accommodated in the housing 16 and sealed in advance. As a constituent material of the casing 16, 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 16 is not particularly limited as long as it contains oxygen, but is preferably air, preferably dry air, or a pressure of 1.01 × 10. An oxygen gas or the like having ⁵ Pa and an oxygen concentration of 99.99% can be used.

  The conditioning method according to the present invention can be performed on such an air battery 10, and the air battery 10 can be manufactured after applying the conditioning method according to the present invention to the power generation unit 15. By performing the conditioning method according to the present invention, the reaction field of the air battery 10 can be increased, the oxygen supply can be promoted, and a battery having excellent coulomb efficiency can be obtained. In addition, after conditioning the power generation unit by the conditioning method according to the present invention, the air cell 10 is manufactured, whereby the reaction field is increased, oxygen supply is promoted, and the air cell 10 having excellent coulomb efficiency is obtained. Can be manufactured.

  Hereinafter, based on an Example, the conditioning method of the air battery which concerns on this invention is demonstrated in detail.

(Production of evaluation cell (air battery))
A layer (thickness: 300 μm) containing ketjen black, MnO ₂ , and a binder (PTFE) in a mass ratio of 80:10:10 was used as an air electrode (positive electrode). The air electrode was provided with Ni 50 mesh (manufactured by Nilaco Corporation, NI-318501) as an air electrode current collector. On the other hand, metallic lithium (Far East Metal, thickness 200 μm, φ15 mm) was used as the negative electrode. Moreover, a nonwoven fabric made of polypropylene (JH1004N, thickness of 200 μm) is used as a separator, and a supporting electrolyte of 0.32 mol / kg as an electrolytic solution (ionic liquid with Li / TFSI added (PP13 / TFSI manufactured by Kanto Chemical Co., Inc.), 1 0.5 mm) was used. Using these, an evaluation cell (F-type cell, manufactured by Hokuto Denko Co., Ltd.) was prepared and evaluated in a glass desiccator equipped with a gas replacement cock (about 50 ml of molecular sieve was installed in the desiccator).

1. Conventional Example The evaluation cell was charged / discharged by low-rate charge / discharge (0.02 mA / cm ² ) performed on a conventional secondary battery. The results are shown in FIG. As shown in FIG. 4, in the conventional low-rate charge / discharge, the initial discharge capacity of the evaluation cell is large, but the charge / discharge cannot be repeated after the second cycle. This is presumably because the discharge product, which is an insulator, covered the electrode surface in the evaluation cell, and no path for electron conduction or oxygen / lithium ion diffusion was formed. After that, conditioning was performed at a high rate, but the discharge capacity could not be recovered.

2. If it continued charging and discharging of the evaluation cell in Reference Example in-rate discharge (0.04mA / cm ^2), and continued to charge and discharge of the evaluation cell at a high-rate discharge (0.1mA / cm ²⁾ For the case, the battery behavior was evaluated. The results are shown in FIG. As shown in FIG. 5, when the medium rate charge / discharge or the high rate charge / discharge was continued, the charge / discharge cycle of the evaluation cell could be repeated. The discharge capacity of the evaluation cell in this case was about 90 mAh / g-positive electrode material for medium rate charge / discharge and about 70 mAh / g-positive electrode material for high rate charge / discharge.

3. Example After charging / discharging cycle related to high rate charge / discharge (0.1 mA / cm ² ) 5 times, switching to medium rate charge / discharge (0.04 mA / cm ² ), and subsequently repeating charge / discharge cycle The battery behavior was evaluated. The results are shown in FIG. As shown in FIG. 6, at the time of high rate charge / discharge, the discharge capacity was about 70 mAh / g-positive electrode material as in FIG. 5, but when switched to medium rate charge / discharge, the discharge capacity was about 180 mAh / g. -Increased to a positive electrode material, and was able to realize a discharge capacity about twice that of the medium rate charge / discharge of FIG. In other words, it was found that by conditioning the air battery at a higher rate than the charge / discharge rate during normal use of the air battery, the discharge capacity of the air battery can be increased and a battery having excellent coulomb efficiency can be obtained. . Further, it was found that an air battery having a high discharge capacity at the time of use can be obtained by preconditioning the battery by performing high-rate charge / discharge before using the battery (during manufacture).

Conditioning conditions (rate, temperature, number of cycles, time required for conditioning, etc.) vary depending on battery components and cannot be uniquely determined. In this embodiment, with respect to the battery to be charged and discharged in the usual 0.04 mA / cm ^2, at 2.5 times the 0.1 mA / cm ^2, by about 50 hours conditioning, as described above, the capacitance characteristics 2 I was able to improve it twice.

  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. The air battery conditioning method, the air battery manufacturing method, and the technical scope of the present invention can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Must be understood as encompassed by.

  According to the present invention, an air battery excellent in coulomb efficiency is obtained, and the air battery can be suitably used as a power source for portable devices, electric vehicles, hybrid vehicles, and the like.

10 Air battery 11 Air electrode 12 Oxygen layer (current collector)
13 Negative Electrode 14 Electrolyte Layer 15 Power Generation Unit 16 Case

Claims (3)

While maintaining the temperature of the air battery having an electrolytic solution 45 to 100 ° C., usually at a high rate compared to the charge and discharge rate at the time of use, charging and discharging of the air battery, method of conditioning air battery. The charge / discharge of the air battery is performed at a higher rate than the charge / discharge rate during the normal use when the capacity of the air battery during the normal use becomes a predetermined value or less. Air battery conditioning method. A power generation unit manufacturing step of manufacturing a power generation unit having an air electrode, an electrolyte containing an electrolyte, and a negative electrode;
A conditioning process for charging and discharging the power generation unit at a higher rate compared to the charge and discharge rate during normal use while maintaining the temperature of the power generation unit at 45 to 100 ° C . ;
A method for manufacturing an air battery.

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