JP2014229522A - Power supply system, and method of preheating battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system or the like capable of heating an electrolyte with efficiency under a low-temperature environment, for example, and of enhancing an ionic conductivity.SOLUTION: A power supply system comprises: a main battery 6 including a positive electrode, a negative electrode, and an electrolyte; and a high-frequency wave generation device 7 for applying a high-frequency voltage to the electrodes of the main battery. The high-frequency wave generation device 7 is operated to apply the high-frequency voltage between the electrodes of the main battery 6, and thereby, the electrolyte is heated.

Description

  The present invention relates to a power supply system and a battery preheating method, and more particularly to a power supply system and a battery preheating method capable of heating the inside of the battery.

  Lithium ion secondary batteries have already been put into practical use as batteries for notebook computers and mobile phones due to advantages such as high energy density, small self-discharge, and excellent long-term reliability. However, in recent years, electronic devices have been enhanced in functionality and used in electric vehicles, and development of lithium ion secondary batteries with higher energy density has been demanded.

  Since this lithium secondary battery has a wide potential window and electrolysis occurs when water is used as the electrolyte, a non-aqueous solvent is used. However, since the non-aqueous solvent has a low lithium ion solubility, the ion conductivity is smaller than that of the aqueous solvent. Therefore, in general, in order to impart high ion conductivity to the lithium secondary battery, a salt that is easily dissociated such as LiPF6 is dissolved. However, a salt that is easily ion-dissociated is generally a salt having a large molecular weight, and when this is dissolved, the viscosity of the electrolytic solution increases. For this reason, when it melt | dissolves in large quantities, it will result in the ionic conductivity falling rather.

  Further, even in a low temperature environment such as winter, the viscosity of the electrolytic solution is increased, so that the ionic conductivity is lowered, and a phenomenon that cannot follow the rapid charge / discharge occurs.

  As a method for increasing the ionic conductivity of the non-aqueous electrolyte, a method in which the inside of the battery is raised to an appropriate temperature before use can be considered. That is, by increasing the temperature, the function of the battery can be improved by a method of decreasing the viscosity of the electrolytic solution and increasing the ionic conductivity. A NAS battery is a practical application of this concept. At normal temperature, solid sodium sulphide is heated to a liquid to enable ionic conduction. However, warming up the entire battery has a large energy loss and takes time, and maintenance is an issue both in terms of equipment and cost, so it has been partially adopted as an installation to stabilize power in factories and the like. Only.

  Moreover, as a technique for increasing the temperature of the battery, Patent Documents 1 and 2 describe a method of heating the entire battery of, for example, a lithium ion secondary battery.

Japanese Patent Application No. 9-89777 (Japanese Patent Laid-Open No. 10-284133) Japanese Patent Application No. 2001-213821 (Japanese Patent Laid-Open No. 2003-032901)

  However, this method is not efficient because energy loss outside the battery is large and battery members other than the electrolyte solution are also heated. In addition, it is possible to secure a power source for heating the battery during charging, but when used for automobiles, motorcycles, bicycles, the power source for driving and gasoline fuel are diverted for heating the entire battery. If the above-described energy loss is large, problems such as a decrease in travel distance occur.

  Therefore, the present invention has been made in view of the above-described problems, and provides a power supply system and a battery preheating method capable of improving battery characteristics by efficiently heating a battery in a low temperature environment, for example. For the purpose.

In order to achieve the above object, a power supply system according to one aspect of the present invention is as follows:
A main battery including a positive electrode, a negative electrode, and an electrolyte;
A high frequency generator for applying a high frequency voltage to the electrode of the main battery;
A power supply system comprising:
A power supply system that operates the high-frequency generator and heats the electrolytic solution by applying a high-frequency voltage between the electrodes.

  The frequency of the high-frequency current can be selected from a frequency region in which only the electrolytic solution obtained from the AC conductivity measurement of the main battery is efficiently heated. For example, the electrolytic solution in the battery can be heated by applying a high frequency whose center potential matches the potential between the positive electrode and the negative electrode of the battery element.

  In addition, the battery has a structure in which a plurality of positive electrodes and negative electrodes are respectively formed, and a high-frequency voltage with a center voltage of 0 V is applied between the positive electrodes or the negative electrodes at the frequency obtained in the same manner as described above. By doing so, the electrolyte solution inside the battery can be heated.

  ADVANTAGE OF THE INVENTION According to this invention, the main battery can be heated rapidly, the power supply system which can heat a battery efficiently, and can improve battery characteristics and the battery preheating method can be provided.

It is a perspective view which shows the structure of a battery. It is a figure which shows the structure of the power supply system which heats electrolyte solution between different electrodes. It is a figure which shows the structure of the battery which has multiple electrodes. It is a figure which shows the structure of the multipolar battery which can heat the electrolyte solution between same poles. It is a figure which shows the structure of the battery system which heats interpolar electrolyte solution. It is a Cole-Cole figure of an example for calculating | requiring the high frequency to apply. It is a figure which shows an example of the relationship between the ionic conductivity of electrolyte solution, and temperature. It is a figure which shows an example of the relationship between the application time of high frequency, and calculation temperature. It is a figure which shows the other structure of the power supply system which heats the electrolyte solution between different electrodes.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an appearance of an example of a battery. The battery 1 generally includes a battery element 2 composed of a positive electrode, a negative electrode, an electrolyte, and the like, an exterior film 3 that seals the battery element 2, and a positive electrode lead terminal and a negative electrode lead terminal that are drawn to the outside of the outer film 3. (4, 5).

  FIG. 2 shows a configuration of an example of a battery system that heats the electrolyte solution between different electrodes. As shown in FIG. 2, the power supply system 20 includes a main battery 6, a high frequency generation circuit 7, an auxiliary battery 8, and the like. Note that the auxiliary battery 8 is not necessarily an essential configuration, and a system that does not include the auxiliary battery 8 may be used (details will be described later with reference to FIG. 9).

  The main battery 6 may be, for example, the battery 1 of FIG. 1, but is not necessarily limited to this, and the battery performance is reduced due to the increase in the viscosity of the electrolyte in a low temperature environment. Any configuration may be used as long as it can cause a problem.

  The auxiliary battery 8 may be basically any battery as long as it can be driven by supplying power to the high-frequency generation circuit 7. As long as the auxiliary battery 8 is not inferior to the main battery in terms of low-temperature characteristics, for example, a battery system having a lower capacity than that of the main battery is used even if a battery having a lower energy density or a higher cost is used. As such, it does not affect energy density or cost.

  In the example of FIG. 2, the high frequency generation circuit 7 is electrically connected to the positive electrode lead terminal and the negative electrode lead terminal (4, 5), and the high frequency signal is generated between the electrodes in the battery via the lead terminal (4, 5). Apply voltage. Details of the high-frequency voltage and the auxiliary battery will be described later again.

  The power supply system 20 also has a switch 10 for switching the connection state of the high frequency generation circuit 7. By operating this switch 10, the battery lead terminal is electrically connected to the high frequency generation circuit 7 and the battery lead terminal is electrically connected to a predetermined load (not shown). It is possible to switch. Switching of the switch 10 may be performed by a user operation, or may be automatically performed at a predetermined timing by a control circuit (not shown) provided in the power supply system 20.

  When the power supply system 20 has a control circuit (not shown) and a predetermined input operation (for example, button operation) is performed by the user, the control circuit issues a control signal, and the switch is based on the control signal. 10 may be automatically switched.

  The power supply system 20 may include a temperature sensor that measures the temperature of the main battery 6 and / or the environmental temperature. In this case, the control circuit (not shown) (i) determines whether or not the detected temperature of the main battery 6 is below a predetermined reference value, and (ii) is below the predetermined reference value. In this case, it is estimated that the viscosity of the electrolytic solution is lowered, and at least a process of starting application of a high-frequency voltage to the main battery may be performed.

  When the power supply system 20 is large, a measuring device that performs AC conductivity measurement (AC impedance measurement) on the main battery may be provided as a part of the power supply system 20. This device is for obtaining a plot (or a numerical value corresponding to it) on the complex impedance surface obtained from the AC conductivity measurement of the main battery, and determines the value of the applied high-frequency voltage based on the measurement result. (It will be described later in detail).

  Next, a method for using the power supply system 20 of the present embodiment configured as described above will be briefly described.

  When the use of the main battery 6 is started, when it is determined that the environmental temperature is low and the viscosity of the electrolyte of the main battery is high, for example, the user performs an operation (example) such as pressing a predetermined button. The switch 10 is switched to apply a high frequency voltage to the main battery 6. Thereby, the high frequency generated using the energy of the auxiliary battery 8 is applied between the electrodes in the main battery 6, and as a result, a high frequency current flows inside the battery and the electrolyte is heated.

  When it is judged that the environmental temperature is low and the viscosity of the electrolyte solution of the main battery is high, it is usually assumed that the ionic conductivity of the battery is low and the performance is not exhibited, but according to this embodiment, The high frequency generated using the energy of the auxiliary battery makes it possible to heat the electrolyte of the main battery, and the discharge rate of the main battery can be improved. When the main battery is operated, it self-heats due to the internal resistance of the main battery, and thereafter there is no need to use the auxiliary battery.

  Regarding the charging of the auxiliary battery 8, the auxiliary battery may be charged together when charging the main battery, and charged using the main battery or other energy for the next use. Is also possible. A specific energy source is a main battery in an electric vehicle, but electricity generated by a gasoline engine in a hybrid vehicle with a gasoline engine. Besides this, it is also possible to use natural energy using wind power or sunlight.

  FIG. 3 shows an exemplary configuration of a battery having a plurality of electrodes. The battery 9 has a plurality of positive electrodes 9c and negative electrodes 9a. The electrodes of the same polarity are connected to each other inside the battery, and the lead terminals (4, 5) are pulled out to the outside, and the exterior film 3 is used. It is hermetically sealed. 2 is the same as the battery configuration in FIG. 2 in that it has one positive lead terminal and one negative lead terminal. In other words, the configuration of FIG. 3 is a battery in which positive electrodes or negative electrodes are divided into two or more sets, and lead terminals corresponding to the respective polarities are drawn out of the film one by one.

On the other hand, FIG. 4 shows a configuration of an example of a multipolar battery capable of heating the electrolyte solution between the same electrodes.
In order to simplify the figure, only two positive electrodes are used. In this battery, a plurality of electrodes (in this case, two positive electrodes) are not connected to each other inside the battery, and are sealed with an exterior film 3 in a state where the respective lead terminals 4 and 4 ′ are pulled out to the outside. Configured. That is, this battery has a configuration having a plurality of lead terminals 4 and 4 ′ having the same polarity.

  FIG. 5 is a diagram illustrating an example of a configuration of a battery system that heats the interpolar electrolyte solution of the battery as illustrated in FIG. 4. The battery system 20 'includes a main battery 6', a high frequency generation circuit 7, a switch 10, and an auxiliary battery 8 as an example. The high frequency generation circuit 7 is connected to the lead terminals 4 and 4 ′ having the same polarity.

  In such a battery system 20 ', when the main battery 6' is heated, a high frequency voltage is applied between the positive electrode lead terminals 4, 4 '. As in the system of FIG. 2, the switch 10 can be switched and used. Note that the switch 10 and the auxiliary battery 8 can be omitted in the same manner as in the system of FIG. 2 described above.

  Next, how to determine the value of the high-frequency voltage applied to the main battery in this embodiment will be described with reference to FIG. FIG. 6 is an example of a Cole-Cole diagram for obtaining a high frequency to be applied. That is, it is a plot on the complex impedance surface obtained from the AC conductivity measurement of the main battery. The resistance value between the real axis intercepts of the first arc from the origin substantially corresponds to the resistance of the electrolytic solution.

Frequency f ₀ above in this section, that is, if the area of the home side in the figure, the bulk resistance and the active material, heating is not at the interface resistance and the charge transfer resistance portion between the active material and the electrolyte, the deterioration of the electrolyte solution Does not occur. On the other hand, the higher the frequency of the applied voltage with respect to the intercept frequency, the smaller the heat generated by the resistance of the electrolytic solution, and the longer the time required for the temperature of the electrolytic solution to rise. Note that the intercept and the value of f ₀ may be obtained graphically using an extrapolation method, a curve fitting method, or the like.

Therefore, a preferable range of the frequency of the applied voltage is 0.9 times to 1.5 times, more preferably 0.95 times to 1.3 times, and still more preferably, with respect to the frequency f ₀ in this intercept. The range is 0.98 times to 1.2 times.

  FIG. 7 is a diagram showing an example of the relationship between the ionic conductivity of the electrolyte and the temperature. The ionic conductivity is proportional to the temperature, and the lower the temperature, the lower the ionic conductivity, and the lower the discharge capacity of the battery. When the electrolyte temperature is heated from minus 10 ° C. to plus 10 ° C. at 20 ° C., the ionic conductivity is approximately doubled, and when heated to 30 ° C. for a total of 40 ° C., the effect is improved approximately three times, and rapid discharge Becomes easier.

  FIG. 8 is a diagram of a simulation result showing an example of the relationship between the application time of high frequency and the calculated temperature. Example of calculating the electrolyte temperature from the Joule heating value when a current of about 3 ItA is passed, assuming that the ratio of the electrolyte in the battery is about 20% by weight and the specific heat of the electrolyte is about 2,000 J / Kg · K. It is. When energized for about 15 seconds, it rises to 20 ° C., and when energized for about 30 seconds, it rises to 30 ° C. In actuality, loss due to latent heat or heat dissipation other than the electrolyte occurs, but the electrolyte can be heated more efficiently than external heating.

  FIG. 9 is a diagram showing another configuration of the power supply system for heating the electrolyte between different electrodes. This power supply system 20 is obtained by omitting the auxiliary battery from the power supply system of FIG. Even if an auxiliary battery is not provided as the power supply system 20, the power supply system 20 is connected to other arbitrary power supply means (not shown) to operate the high-frequency generation circuit 7, so that FIG. The same effect as the form can be obtained.

  The battery element of the present invention is not particularly limited, but is preferably a battery element of a lithium ion secondary battery. Hereinafter, preferred battery element materials will be described.

[1] Negative electrode The negative electrode is formed, for example, by binding a negative electrode active material to a negative electrode current collector with a negative electrode binder. As long as the negative electrode active material in this embodiment can occlude and release lithium, any material can be used as long as the effects of the present invention are not significantly impaired. Usually, as in the case of the positive electrode, a negative electrode having a negative electrode active material layer provided on a current collector is used. Note that, similarly to the positive electrode, the negative electrode may include other layers as appropriate.

  The negative electrode active material is not particularly limited as long as it is a material capable of occluding and releasing lithium ions, and a known negative electrode active material can be arbitrarily used. For example, carbonaceous materials such as coke, acetylene black, mesophase microbeads, and graphite; lithium metal; lithium alloys such as lithium-silicon and lithium-tin, and lithium titanate are preferably used. Among these, it is most preferable to use a carbonaceous material in terms of good cycle characteristics and safety and excellent continuous charge characteristics. In addition, a negative electrode active material may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Further, the particle size of the negative electrode active material is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 1 μm or more, preferably 15 μm in terms of excellent battery characteristics such as initial efficiency, rate characteristics, and cycle characteristics. These are usually 50 μm or less, preferably about 30 μm or less. In addition, for example, those obtained by coating the above carbonaceous material with an organic substance such as pitch and then firing, those obtained by forming amorphous carbon on the surface using the CVD method, etc. It can be suitably used as a quality material. Here, organic substances used for coating include coal tar pitch from soft pitch to hard pitch; coal heavy oil such as dry distillation liquefied oil; straight heavy oil such as atmospheric residual oil and vacuum residual oil; crude oil And petroleum heavy oils such as cracked heavy oil (for example, ethylene heavy end) produced as a by-product during thermal decomposition of naphtha and the like. Moreover, what grind | pulverized the solid residue obtained by distilling these heavy oils at 200-400 degreeC to 1-100 micrometers can also be used. Furthermore, a vinyl chloride resin, a phenol resin, an imide resin, etc. can also be used.

  For example, the negative electrode active material layer can be formed into a sheet electrode by roll molding the negative electrode active material described above, or a pellet electrode by compression molding. Usually, as in the case of the positive electrode active material layer, The negative electrode active material, the binder, and, if necessary, various auxiliary agents and the like can be produced by applying a coating solution obtained by slurrying with a solvent onto a current collector and drying it. it can.

  The binder for the negative electrode is not particularly limited. For example, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer. Rubber, polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamideimide, carboxymethylcellulose, and the like can be used. The amount of the binder for the negative electrode used is 0.5 to 25 parts by mass with respect to 100 parts by mass of the negative electrode active material from the viewpoints of “sufficient binding force” and “higher energy” which are in a trade-off relationship. Is preferred.

[2] Current collector As the material for the current collector of the negative electrode, a known material can be arbitrarily used. For example, a metal material such as copper, nickel, or SUS is used. Among these, copper is particularly preferable from the viewpoint of ease of processing and cost. The negative electrode current collector is also preferably subjected to a roughening treatment in advance. Furthermore, the shape of the current collector is also arbitrary, and examples thereof include a foil shape, a flat plate shape, and a mesh shape. Also, a perforated current collector such as expanded metal or punching metal can be used.

  For example, the negative electrode can be manufactured by forming a negative electrode active material layer including a negative electrode active material and a negative electrode binder on a negative electrode current collector. Examples of the method for forming the negative electrode active material layer include a doctor blade method, a die coater method, a CVD method, and a sputtering method. After forming a negative electrode active material layer in advance, a thin film of aluminum, nickel, or an alloy thereof may be formed by a method such as vapor deposition or sputtering to form a negative electrode current collector.

[3] Positive electrode Examples of the positive electrode active material include a lithium-containing composite oxide having a layered structure such as LiMnO ₂ and Li _x Mn ₂ O ₄ (0 <x <2), a lithium-containing composite oxide having a spinel structure, LiCoO ₂ , LiNiO ₂ , compounds in which some of these transition metals are substituted with other metals, olivine compounds such as LiFePO ₄ , LiMnPO ₄ , Li ₂ MSiO ₄ (M: at least one of Mn, Fe, Co) ) Etc. can be used. In particular, as the positive electrode active material contained in the positive electrode, a lithium-containing composite oxide having a spinel structure is preferable because it exhibits a high operating voltage. As the lithium-containing complex oxide having a spinel structure, for example, a portion of the _{LiMn 2 O 4, LiNi 0.5 Mn} 1.5 O 4 Mn of LiMn ₂ O _4, such as Ni, Cr, Co, Fe, Ti , Si, Al, Mg and the like substituted compounds. These may use only 1 type and may use 2 or more types together. The positive electrode is formed, for example, by binding a positive electrode active material so as to cover the positive electrode current collector with a positive electrode binder. Other positive electrode active materials include lithium manganate having a layered structure such as LiMnO ₂ , Li _x Mn ₂ O ₄ (0 <x <2) or lithium manganate having a spinel structure; LiCoO ₂ , LiNiO _2, or these Some transition metals are replaced with other metals; lithium transition metal oxides, such as LiNi _1/3 Co _1/3 Mn _1/3 O _{2, and the} like that do not exceed half the specific transition metals; these lithium transition metals Examples of the oxide include those in which Li is excessive compared to the stoichiometric composition. In particular, Li _α Ni _β Co _γ Al _δ O ₂ (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.7, γ ≦ 0.2) or Li _α Ni _β Co _γ Mn _δ O ₂ (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.6, γ ≦ 0.2) are preferable. A positive electrode active material can be used individually by 1 type or in combination of 2 or more types.

  As the positive electrode binder, the same negative electrode binder can be used. Among these, polyvinylidene fluoride is preferable from the viewpoint of versatility and low cost. The amount of the binder for the positive electrode to be used is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the positive electrode active material from the viewpoints of “sufficient binding force” and “high energy” which are in a trade-off relationship. .

  As the positive electrode current collector, the same as the negative electrode current collector can be used.

  A conductive auxiliary material may be added to the positive electrode active material layer containing the positive electrode active material for the purpose of reducing impedance. Examples of the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.

[4] Electrolytic Solution As the electrolytic solution used in the present embodiment, a nonaqueous electrolytic solution containing a lithium salt (supporting salt) and a nonaqueous solvent that dissolves the supporting salt can be used.

  Nonaqueous solvents include carbonic acid esters (chain or cyclic carbonates), carboxylic acid esters (chain or cyclic carboxylic acid esters), phosphoric acid esters, and the like, and some of the hydrogen atoms of these compounds are substituted with fluorine atoms. An aprotic organic solvent such as a fluorinated solvent can be used.

  Examples of the carbonate (carbonate) solvent include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC); dimethyl carbonate (DMC), diethyl carbonate (DEC), Chain carbonates such as ethyl methyl carbonate (EMC) and dipropyl carbonate (DPC); and propylene carbonate derivatives.

  Examples of the carboxylic acid ester solvent include aliphatic carboxylic acid esters such as methyl formate, methyl acetate, and ethyl propionate; and lactones such as γ-butyrolactone.

As the phosphate ester, a phosphate ester represented by the following formula can be used.
O = P (—O—R ₁ ) (— O—R ₂ ) (— O—R ₃ )
(In the formula, R ₁ , R ₂ and R ₃ are each independently an alkyl group)

  Examples of the phosphate ester include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, trioctyl phosphate, and triphenyl phosphate.

  Among these, electrolytes include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (MEC). It is preferable that carbonic acid esters (cyclic or chain carbonates) such as dipropyl carbonate (DPC) are included.

  In addition, the electrolytic solution is a fluorinated carbonate in which some hydrogen atoms of carbonate are substituted with fluorine atoms, a fluorinated carboxylate ester in which some hydrogen atoms in carboxylic acid ester are substituted with fluorine atoms, or a phosphate ester. May include a fluorinated phosphate ester in which some of the hydrogen atoms are substituted with fluorine atoms, and preferably includes a fluorinated carbonate or a fluorinated phosphate ester.

  The content of the fluorinated carbonate is preferably 0.01% by mass or more and 50% by mass or less in the nonaqueous electrolytic solution. When the fluorinated carbonate is contained in the electrolytic solution, the discharge capacity becomes large, but when it is too much, the viscosity in the electrolytic solution tends to increase and the resistance tends to increase. Therefore, the content of the fluorinated carbonate is preferably 0.1% by mass or more, more preferably 1% by mass or more, and more preferably 2% by mass or more in the nonaqueous electrolytic solution. Further, the content of the fluorinated carbonate is preferably 30% by mass or less, more preferably 15% by mass or less, and more preferably 10% by mass or less in the nonaqueous electrolytic solution.

  Other solvents that can be contained in the non-aqueous electrolyte include, for example, ethylene sulfite (ES), propane sultone (PS), butane sultone (BS), dioxathilane-2,2-dioxide (DD), and sulfolene. 3-methylsulfolene, sulfolane (SL), succinic anhydride (SUCAH), propionic anhydride, acetic anhydride, maleic anhydride, diallyl carbonate (DAC), dimethyl 2,5-dioxahexanoate, 2,5 -Dioxahexaneniate dimethyl, furan, 2,5-dimethylfuran, diphenyl disulfide (DPS), dimethoxyethane (DME), dimethoxymethane (DMM), diethoxyethane (DEE), ethoxymethoxyethane, chloroethylene carbonate , Dimethyl ether, methyl ether Ether, methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, diethyl ether, phenyl methyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), tetrahydropyran (THP), 1,4-dioxane (DIOX), 1,3-dioxolane (DOL), methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl difluoroacetate, methyl propionate, ethyl propionate, propyl propionate, methyl formate , Ethyl formate, ethyl butyrate, isopropyl butyrate, methyl isobutyrate, methyl cyanoacetate, vinyl acetate, diphenyl Disulfide, dimethyl sulfide, diethyl sulfide, adiponitrile, valeronitrile, glutaronitrile, malononitrile, succinonitrile, pimonitrile, suberonitrile, isobutyronitrile, biphenyl, thiophene, methyl ethyl ketone, fluorobenzene, hexafluorobenzene, glyme, ether, acetonitrile , Propiononitrile, γ-valerolactone, dimethyl sulfoxide (DMSO), ionic liquid, phosphazene, or a compound in which some hydrogen atoms of these compounds are substituted with fluorine atoms.

In addition, the electrolytic solution is a fluorine represented by R _v1 —O—R _v2 (R _v1 and R _v2 are each independently an alkyl group or a fluorine-containing alkyl group, at least one of which is a fluorine-containing alkyl group). Ether, O═P (—O—R ₁ ) (— O—R ₂ ) (— O—R ₃ ) (wherein R ₁ , R ₂ and R ₃ are each independently an alkyl group or a fluorine-containing alkyl group) The flame retardant effect can be further increased by including at least one selected from a phosphate ester, an ionic liquid, and a phosphazene.

  Examples of the fluorinated ether include compounds in which some of hydrogen atoms of dimethyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, or diethyl ether are substituted with fluorine atoms.

  A non-aqueous solvent can be used individually by 1 type or in combination of 2 or more types.

Examples of the supporting salt include LiPF ₆ , LiAsF ₆ , LiAlCl ₄ , LiClO ₄ , LiBF ₄ , LiSbF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiN (CF ₃ SO ₂ ) Lithium salts that can be used for ordinary lithium ion batteries such as ₂ can be used. The supporting salt can be used alone or in combination of two or more.

[5] Separator The separator is not particularly limited, but a porous film or nonwoven fabric such as polypropylene, polyethylene, fluorine-based resin, polyamide, polyimide, polyester, polyphenylene sulfide, or the like as a base material. What adhered or joined inorganic substances, such as an alumina and glass, and processed independently as a nonwoven fabric or cloth can be used. Moreover, what laminated | stacked them can also be used as a separator.

[6] Auxiliary battery As a battery that can be used as the auxiliary battery, a secondary battery that can be repeatedly heated with respect to the main battery is preferable. Lead storage battery, lithium / air battery, lithium ion secondary battery, lithium ion polymer secondary battery, iron phosphate lithium ion battery, lithium / sulfur battery, titanate / lithium battery, nickel / cadmium storage battery, nickel / hydrogen rechargeable battery, Examples include nickel / iron batteries, nickel / lithium batteries, nickel / zinc batteries, rechargeable alkaline batteries, sodium / sulfur batteries, redox flow batteries, zinc / bromine flow batteries, and silicon batteries.

  In addition, those capable of low-temperature operation are preferable, lead storage battery, lithium / air battery, lithium ion secondary battery, lithium ion polymer secondary battery, lithium iron phosphate battery, titanic acid / lithium battery, nickel / cadmium storage battery, Examples include nickel / hydrogen rechargeable batteries, nickel / iron batteries, nickel / lithium batteries, nickel / zinc batteries, rechargeable alkaline batteries, redox flow batteries, zinc / bromine flow batteries, and silicon batteries.

[7] High-frequency generator The high-frequency generator is a device for applying an AC voltage from a DC auxiliary battery (example) to the main battery. When applying a high-frequency voltage between the different polarities of the main battery, adjust the AC center potential to the same potential as the main battery potential (in other words, the center potential is the same or substantially the same as the main battery potential). It is preferable to apply an alternating voltage.

  When the center potential is higher than the full charge potential of the main battery, the battery is overcharged, which may adversely affect the battery life and safety. Therefore, for example, when the full charge potential of the main battery is about 4 to 5 V, the difference (Eu = Ec−Ef) between the applied AC center voltage (Ec) and the full charge potential (Ef) of the main battery is preferably Is 0.5 V or less, more preferably 0.3 V or less, and still more preferably 0.1 V or less.

  On the other hand, when the center voltage (Ec) is lower than the potential (Er) of the main battery, the main battery is in a discharged state, so the capacity of the main battery decreases. Therefore, the difference (El = Er−Ec) is preferably 0.5 V or less, more preferably 0.3 V or less, and still more preferably 0.1 V or less.

  When a high frequency voltage is applied between the same poles of the main battery, the center potential is preferably adjusted to 0V. When the center potential is deviated from 0V, the balance between the electrodes is lost, which may cause a phenomenon that the electromotive voltage is lowered when the main battery is used and a phenomenon that the life of the battery is shortened. For this reason, the absolute value of the central potential of the alternating current applied is preferably 0.3 V or less, more preferably 0.2 V or less, and even more preferably 0.1 V or less.

  The frequency to be applied is described in the description of FIG. 6, but the frequency of the intercept of the real axis obtained by the AC conductivity measurement can heat the electrolyte most efficiently, and the preferable frequency range of the applied voltage is this intercept. The frequency is 0.9 to 1.5 times, preferably 0.95 to 1.3 times, and more preferably 0.98 to 1.2 times.

  In the battery system of this embodiment, the high-frequency current flowing through the main battery is an energy source that causes the temperature of the electrolyte to rise. Since it is more practical that the time required for heating the electrolyte is shorter, it is preferable that the integral amount of the current is larger. Specifically, the average heating current of the main battery is 0.01 ItA or more, preferably 0.1 ItA or more, and more preferably 0.5 ItA or more.

  However, depending on the potential and capacity of the auxiliary battery and the usage, there are restrictions due to its volume and weight. Moreover, a rapid temperature rise is caused by an excessive current, and non-uniform overheating of the electrolyte is induced. Therefore, the average heating current of the main battery is preferably 30 ItA or less, preferably 10 ItA or less, and more preferably 3 ItA or less.

  The battery element of the present invention is not limited to the battery element of the above lithium ion secondary battery, and can be applied to any battery as long as it is desired to operate at a temperature higher than the environmental temperature.

  According to the battery preheating method of this embodiment described above, a high frequency voltage can be applied to the battery, and only the temperature of the electrolytic solution can be quickly and efficiently adjusted to an appropriate temperature. Since it can be heated to an appropriate temperature in a short time, this method may be used immediately before using the battery, which is efficient.

  If charging and discharging with alternating current is repeated at a high potential in the charged state, the electrolyte deterioration on the positive electrode surface, the reduction deterioration of the electrolyte solution on the negative electrode surface is accelerated, and the battery capacity decreases in a short period of time. is there. However, this deterioration can be prevented by controlling the frequency within a predetermined range.

  Furthermore, in the case of a stacked battery having a plurality of positive electrodes or negative electrodes in the battery, the center potential of the applied high frequency is set to zero volts by designing a battery circuit that can apply a high frequency voltage between the positive electrodes or between the negative electrodes. be able to. Therefore, it is possible to design the voltage of the power source used for heating low, and it is possible to select an electrode that does not affect the deterioration of the electrolytic solution. In other words, a high-frequency voltage may be applied between the positive electrodes if the battery causes deterioration of the electrolytic solution in the negative electrode, and a high-frequency voltage may be applied between the positive electrodes if the battery causes deterioration of the electrolytic solution in the positive electrode.

  The battery according to the invention can be used, for example, in all industrial fields that require a power source, as well as in industrial fields related to the transport, storage and supply of electrical energy. Specifically, power supplies for mobile devices such as mobile phones and notebook computers; power supplies for transportation and transportation media such as trains, satellites, and submarines, including electric vehicles such as electric cars, hybrid cars, electric bikes, and electric assist bicycles A backup power source such as a UPS; a power storage facility for storing power generated by solar power generation, wind power generation, etc .;

(Appendix)
This application discloses the following inventions:
1. A main battery including a positive electrode, a negative electrode, and an electrolyte;
A high frequency generator for applying a high frequency voltage to the electrode of the main battery;
A power supply system comprising:
A power supply system that operates the high-frequency generator and heats the electrolytic solution by applying a high-frequency voltage between the electrodes.

2. further,
2. The power supply system according to 1 above, comprising an auxiliary battery connected to the high frequency generator.

3. further,
3. The power supply system according to 1 or 2 above, further comprising a switch that switches a connection state between the high-frequency generator and the main battery.

4). Any of the above 1-3, wherein the frequency of the high-frequency voltage is a value in the range of 0.9 to 1.5 times the frequency of the intercept of the real axis obtained by measuring the AC conductivity of the main battery. The power supply system as described in one.

5. 5. The power supply according to 4 above, wherein the frequency of the high-frequency voltage is a value within a range of 0.95 times to 1.3 times the frequency of the intercept of the real axis obtained by measuring AC conductivity of the main battery. system.

6). 5. The power supply according to 4 above, wherein the frequency of the high-frequency voltage is a value within a range of 0.98 to 1.2 times the frequency of the intercept of the real axis obtained by measuring the AC conductivity of the main battery. system.

7). When applying a high frequency voltage between different poles,
The center potential of the applied high frequency is not more than a value obtained by adding 0.5 V to the full charge potential of the main battery, and is not less than a value obtained by subtracting 0.5 V from the full charge potential of the main battery.
The power supply system according to any one of 1 to 6 above.

8). The main battery has a plurality of the same polarity, and the electrodes of the same polarity are not coupled together in the battery, and lead terminals are connected to each,
The power supply system according to any one of the above 1 to 7, configured to be able to apply a high-frequency voltage between the electrodes via the lead terminals.

9. 6. The power supply system according to 5 above, wherein when a voltage is applied between the electrodes having the same polarity, an absolute value of a center potential of the high-frequency voltage is 0.3 V or less.

10. The electrolyte solution includes any one of 1 to 9 above, which includes carbonic acid ester, carboxylic acid ester, phosphoric acid ester, and one selected from those obtained by substituting some hydrogen elements of these compounds with fluorine atoms. Power supply system as described in.

11. An automobile equipped with any one of the power supply systems 1 to 10 above.

12 A large-scale power storage system equipped with any one of the power supply systems 1 to 10 above.

13. A method for preheating a battery electrolyte,
A method for preheating a battery, comprising applying a high-frequency voltage between electrodes of a main battery including a positive electrode, a negative electrode, and an electrolytic solution.

14 In the step of applying the high frequency voltage,
Applying a voltage between electrodes of different polarity, or applying a voltage between electrodes of the same polarity but separately provided,
14. The method for preheating a battery as described in 13 above.

DESCRIPTION OF SYMBOLS 1 Film exterior battery 2 Battery element 3 Exterior film 4 Positive electrode lead terminal 5 Negative electrode lead terminal 6 Main battery
7 High-frequency generation circuit 8 Auxiliary battery for heating 9 Battery having multiple electrodes 9a Negative electrode 9b Separator 9c Positive electrode 10 Switch

Claims (14)

A main battery including a positive electrode, a negative electrode, and an electrolyte;
A high frequency generator for applying a high frequency voltage to the electrode of the main battery;
A power supply system comprising:
A power supply system that operates the high-frequency generator and heats the electrolytic solution by applying a high-frequency voltage between the electrodes. further,
The power supply system according to claim 1, comprising an auxiliary battery connected to the high-frequency generator. further,
The power supply system of Claim 1 or 2 provided with the switch which switches the connection state of the said high frequency generator and the said main battery.   The frequency of the high-frequency voltage is a value within a range of 0.9 to 1.5 times the frequency of the intercept of the real axis obtained by measuring the AC conductivity of the main battery. The power supply system according to any one of the above.   The frequency of the high-frequency voltage is a value within a range of 0.95 to 1.3 times the frequency of the intercept of the real axis obtained by measuring the AC conductivity of the main battery. Power system.   The frequency of the high-frequency voltage is a value within a range of 0.98 times to 1.2 times the frequency of the intercept of the real axis obtained by measuring the AC conductivity of the main battery. Power system. When applying a high frequency voltage between different poles,
The center potential of the applied high frequency is not more than a value obtained by adding 0.5 V to the full charge potential of the main battery, and is not less than a value obtained by subtracting 0.5 V from the full charge potential of the main battery.
The power supply system as described in any one of Claims 1-6. The main battery has a plurality of the same polarity, and the electrodes of the same polarity are not coupled together in the battery, and lead terminals are connected to each,
It is configured to be able to apply a high-frequency voltage between the electrodes via the lead terminals,
The power supply system as described in any one of Claims 1-7.   The power supply system according to claim 5, wherein an absolute value of a center potential of the high-frequency voltage is 0.3 V or less when a voltage is applied between the electrodes having the same polarity.   10. The electrolyte solution according to claim 1, wherein the electrolyte includes one selected from a carbonate ester, a carboxylate ester, a phosphate ester, and a compound in which a part of hydrogen elements of these compounds are substituted with fluorine atoms. The power supply system described in the section.   An automobile equipped with the power supply system according to any one of claims 1 to 10.   A large-scale power storage system equipped with the power supply system according to claim 1. A method for preheating a battery electrolyte,
A method for preheating a battery, comprising applying a high-frequency voltage between electrodes of a main battery including a positive electrode, a negative electrode, and an electrolytic solution. In the step of applying the high frequency voltage,
Applying a voltage between electrodes of different polarity, or applying a voltage between electrodes of the same polarity but separately provided,
The battery preheating method according to claim 13.