JP2021086662A - Lithium ion secondary battery, current control circuit, and capacity-recovering method of lithium ion secondary battery - Google Patents

Abstract

To provide a lithium ion secondary battery which can eliminate an initial irreversible capacity without largely changing a conventional battery configuration, and which allows a capacity reduced by repetition of charge and discharge to be recovered.SOLUTION: A lithium ion secondary battery comprises: a positive electrode connected to a positive electrode terminal; a negative electrode connected to a negative electrode terminal; an electrolyte solution; a lithium ion-supplying electrode serving to supply lithium ions to the positive electrode, the negative electrode or the electrolyte solution; a case; a current control circuit in the case, which includes a switching element for controlling the connection of the lithium ion-supplying electrode with the positive electrode or the negative electrode; and a control signal generation mechanism serving to generate a control signal outside the case. The switching element operates on the basis of the control signal from the control signal generation mechanism.SELECTED DRAWING: Figure 1A

Description

The present invention relates to a lithium ion secondary battery, a current control circuit, and a method for recovering the capacity of the lithium ion secondary battery.

Energy capacity is large in load leveling devices such as solar power generation and wind power generation, instantaneous voltage drop countermeasure devices for electronic devices such as computers, and energy storage systems such as energy regeneration devices for electric vehicles and hybrid cars. There is a need for a power storage device capable of rapid charging and discharging. Lithium-ion secondary batteries and lithium-ion capacitors have been proposed as power storage devices capable of such rapid charge / discharge and long life.

The lithium ion secondary battery uses a lithium metal oxide such as lithium cobalt oxide for the positive electrode, and can store electric charges by using lithium ions as the lithium ion metal oxide. Further, in the negative electrode, lithium ions can be stored between layers of the carbon material. Further, since a non-aqueous electrolytic solution can be used to obtain a large potential difference between the electrodes, a large amount of energy can be stored.

In a conventional lithium ion secondary battery, charging and discharging are performed by passing lithium ions between the positive electrode and the negative electrode, but some lithium ions remain trapped in the negative electrode, so that the capacity is irreversible at the initial stage. There is a problem that the amount of lithium ions involved in the transfer decreases and the capacity gradually decreases by repeating charging and discharging over a long period of time.

In response to the above problem, a technique has been proposed in which a third electrode and a third electrode serving as a lithium ion supply source are provided in the lithium ion secondary battery. However, when the terminal from the third electrode is provided outside the battery case, , There is a problem that the electrode configuration becomes complicated because equipment for connecting to other electrodes and turning on / off is required.

In order to solve these problems, for example, Patent Document 1 has three electrodes of lithium poles containing lithium in advance together with a positive electrode and a negative electrode, and has an electrical insulation / connection function between the electrodes. A lithium ion secondary battery having a characteristic three-electrode has been proposed.

Then, in the above-mentioned lithium ion secondary battery, before sealing, a shape memory alloy or the like is used to raise the temperature of the battery, the shape memory alloy is extended, the lithium electrode is connected to the negative electrode and discharged, and the lithium electrode is discharged. Lithium ions are transferred from the negative electrode to the negative electrode, and then the lithium electrode and the negative electrode are insulated by the insulation / connection function, and the negative electrode and the positive electrode are connected to move the lithium ions from the negative electrode to the positive electrode.

According to the above-mentioned lithium ion secondary battery, by causing an electrode reaction between the lithium electrode and the negative electrode in advance, lithium ions corresponding to the irreversible capacity are moved to the negative electrode, and the irreversible capacity generated in the first charge is eliminated. It is said that it can be done.

Japanese Unexamined Patent Publication No. 2000-306608

However, according to Patent Document 1, the method described in Patent Document 1 can eliminate the initial irreversible capacitance, but what is described about recovering the capacitance after repeated charging and discharging. There was no suggestion.

The present invention has been made in view of the above problems, and its main purpose is to eliminate the initial irreversible capacity without significantly changing the conventional battery configuration, and to reduce the initial irreversible capacity by repeating charging and discharging. It is an object of the present invention to provide a lithium ion secondary battery capable of recovering the generated capacity, a current control circuit included in the lithium ion secondary battery, and a method for recovering the capacity of the lithium ion secondary battery using the current control circuit. ..

That is, the lithium ion secondary battery of the present invention has a positive electrode connected to a positive electrode terminal, a negative electrode connected to a negative electrode terminal, an electrolytic solution, and lithium that supplies lithium ions to the positive electrode, the negative electrode, or the electrolytic solution. A lithium ion secondary battery having an ion supply electrode and a case.
A current control circuit including a switching element for controlling the connection between the lithium ion supply electrode and the positive electrode or the negative electrode is provided inside the case, and a control signal generation mechanism for generating a control signal is provided outside the case. The switching element is characterized in that it operates based on a control signal from the control signal generation mechanism.

According to the lithium ion secondary battery, the current control circuit including the switching element inside the case is controlled from the outside of the case before charging / discharging or at a predetermined time within the charging / discharging period to control the lithium ion. By connecting the supply electrode to the positive electrode or the negative electrode, lithium ions can be supplied to the positive electrode, the negative electrode or the electrolytic solution, the initial irreversible capacity can be eliminated, and the capacity reduced by repeated charging and discharging can be eliminated. Can be recovered.

Further, since the lithium ion secondary battery of the present invention is provided with a current control circuit inside the case and has only positive electrode terminals and negative electrode terminals as connection terminals with the outside of the case, it is connected to the conventional one. The lithium ion secondary battery of the present invention can be used without changing the method.

In the lithium ion secondary battery of the present invention, it is desirable that the current control circuit includes the switching element and a resistor connected in series with the switching element.

In the lithium ion secondary battery of the present invention, when the current control circuit includes the switching element and a resistor connected in series with the switching element, the lithium ion supply electrode and the positive electrode or the negative electrode It is possible to keep the current flowing between the lithium ion supply electrode and the positive electrode or the negative electrode in an appropriate range at the time of connection.

In the lithium ion secondary battery of the present invention, it is desirable that the current control circuit includes the switching element and a diode connected in series with the switching element.

In the lithium ion secondary battery of the present invention, if the current control circuit includes the switching element and a diode connected in series with the switching element, when the lithium ion supply electrode is connected to the positive electrode or the negative electrode, the current control circuit is connected. Even when the potential is reversed due to over-discharging or the like, it is possible to prevent the current from flowing in the direction opposite to the target direction, and it is possible to prevent an accident or the like from occurring due to the backflow.

In the lithium ion secondary battery of the present invention, the switching element is a magnetic switch, and it is desirable that the control signal generation mechanism magnetically controls on / off of the magnetic switch.

In the lithium ion secondary battery of the present invention, if the switching element is a magnetic switch and the control signal generation mechanism can magnetically control the on / off of the magnetic switch, a simple operation can be performed at any time. The lithium ion supply electrode can be connected and insulated from the positive electrode or the negative electrode.

In the lithium ion secondary battery of the present invention, the switching element is a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal to control the current flowing through the semiconductor element. It is desirable to control the on / off of the semiconductor element by doing so.

In the lithium ion secondary battery of the present invention, the switching element is a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal to control the current flowing through the semiconductor element. As a result, if the on / off control of the semiconductor element can be performed, the lithium ion supply electrode can be connected and insulated from the positive electrode or the negative electrode at an arbitrary time by a simple operation.

The current control circuit of the present invention includes a positive electrode connected to a positive electrode terminal, a negative electrode connected to a negative electrode terminal, an electrolytic solution, and a lithium ion supply electrode that supplies lithium ions to the positive electrode, the negative electrode, or the electrolytic solution. A current control circuit that controls the connection between the lithium ion supply electrode that supplies the lithium ions and the positive electrode or the negative electrode in the lithium ion secondary battery having the case.
The current control circuit is arranged inside the case and has a switching element.
The switching element is characterized in that it operates based on a control signal transmitted from the outside of the case.

According to the current control circuit of the present invention, the switching element provided in the current control circuit can be turned on / off based on the control signal from the outside of the case, so that it can be turned on / off before charging / discharging or within the charging / discharging period. Lithium ions can be supplied to the positive electrode, the negative electrode, or the electrolytic solution at a predetermined time, the initial irreversible capacity can be eliminated, and the capacity reduced by repeated charging and discharging can be recovered.

In the current control circuit of the present invention, it is desirable that the current control circuit includes the switching element and a resistor connected in series with the switching element.

In the current control circuit of the present invention, when the current control circuit includes the switching element and a resistor connected in series with the switching element, the lithium ion supply electrode is connected to the positive electrode or the negative electrode. Sometimes the current flowing between the lithium ion supply electrode and the positive or negative electrode can be kept in an appropriate range.

In the current control circuit of the present invention, it is desirable that the current control circuit includes the switching element and a diode connected in series with the switching element.

In the current control circuit of the present invention, if the current control circuit includes the switching element and a diode connected in series with the switching element, when the lithium ion supply electrode is connected to the positive electrode or the negative electrode, the current control circuit is connected. Even when the potential is reversed due to over-discharging or the like, it is possible to prevent the current from flowing in the direction opposite to the target direction, and it is possible to prevent an accident or the like from occurring due to the backflow.

In the current control circuit of the present invention, the switching element is a magnetic switch, and the control signal generation mechanism generates a magnetic control signal and controls the current input to the magnetic switch to perform on / off control. Is desirable.

In the current control circuit of the present invention, the switching element is a magnetic switch, and the control signal generation mechanism generates a magnetic control signal and controls the current input to the magnetic switch to perform on / off control. If possible, the lithium ion supply electrode can be connected and insulated from the positive electrode or the negative electrode at any time with a simple operation.

In the current control circuit of the present invention, the switching element is a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal to control the current flowing through the semiconductor element. It is desirable to control the on / off of the semiconductor element.

In the current control circuit of the present invention, the switching element is a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal to control the current flowing through the semiconductor element. If the on / off control of the semiconductor element can be performed, the lithium ion supply electrode can be connected and insulated from the positive electrode or the negative electrode at any time by a simple operation.

The capacity recovery method of the lithium ion secondary battery of the present invention is the above-mentioned capacity recovery method of the lithium ion secondary battery.
By generating a control signal from the control signal generation mechanism, the lithium ion supply electrode and the positive electrode or the negative electrode are connected via the switching element, and before charging / discharging or at a predetermined time within the charging / discharging period. It is characterized in that lithium ions are supplied from the lithium ion supply electrode to the positive electrode, the negative electrode or the electrolytic solution to recover the capacity of the lithium ion secondary battery.

According to the lithium ion secondary battery of the present invention, a switching element constituting a current control circuit provided inside the case by generating a control signal from a control signal generation mechanism provided outside the case. Since it can be turned on and off, lithium ions can be supplied to the positive electrode, the negative electrode, or the electrolytic solution before charging / discharging or at a predetermined time within the charging / discharging period with a simple operation, and the initial irreversible capacity can be supplied. Can be eliminated, and the capacity reduced by repeated charging and discharging can be recovered.

According to the lithium ion secondary battery of the present invention, the lithium ion supply electrode and the positive electrode are used before charging / discharging or at a predetermined time within the charging / discharging period by using the current control circuit including the switching element inside the case. Alternatively, by connecting to the negative electrode, lithium ions can be supplied to the positive electrode, the negative electrode, or the electrolytic solution, the initial irreversible capacity can be eliminated, and the capacity reduced by repeated charging and discharging can be recovered. it can. Further, the lithium ion secondary battery of the present invention can be used without changing the connection method from the conventional one.

Further, according to the current control circuit of the present invention, the switching element provided in the current control circuit can be turned on / off based on the control signal from the outside of the case, so that it is before charging / discharging or during the charging / discharging period. Lithium ions can be supplied to the positive electrode, the negative electrode, or the electrolytic solution at a predetermined time, the initial irreversible capacity can be eliminated, and the capacity reduced by repeated charging and discharging can be recovered.

Further, according to the capacity recovery method of the lithium ion secondary battery of the present invention, a current control circuit provided inside the case is generated by generating a control signal from a control signal generation mechanism provided outside the case. Since the switching elements constituting the above can be turned on and off, lithium ions can be supplied to the positive electrode, the negative electrode or the electrolytic solution before charging / discharging or at a predetermined time within the charging / discharging period by a simple operation. Therefore, the initial irreversible capacity can be eliminated, and the capacity reduced by repeated charging and discharging can be recovered.

FIG. 1A is a schematic cross-sectional view schematically showing an embodiment of a lithium ion secondary battery in which the positive electrode and the lithium electrode of the present invention are connected. FIG. 1B is a schematic cross-sectional view schematically showing another embodiment of a lithium ion secondary battery in which the negative electrode and the lithium electrode of the present invention are connected. FIG. 2 is a circuit diagram showing an example of a current control circuit. FIG. 3 is a circuit diagram showing a switching circuit including a transistor. FIG. 4 is a circuit diagram showing a switching circuit including a MOS-FET. FIG. 5 is a schematic cross-sectional view schematically showing another embodiment of the lithium ion secondary battery of the present invention.

(Detailed description of the invention)
The lithium ion secondary battery of the present invention supplies a positive electrode connected to a positive electrode terminal, a negative electrode connected to a negative electrode terminal, an electrolytic solution, and a lithium ion supply that supplies lithium ions to the positive electrode, the negative electrode, or the electrolytic solution. A lithium-ion secondary battery having a pole and a case,
A current control circuit including a switching element for controlling the connection between the lithium ion supply electrode and the positive electrode or the negative electrode is provided inside the case, and a control signal generation mechanism for generating a control signal is provided outside the case. The switching element is characterized in that it operates based on a control signal from the control signal generation mechanism.

FIG. 1A is a schematic cross-sectional view schematically showing an embodiment of a lithium ion secondary battery in which a positive electrode of the present invention and a lithium electrode are connected, and FIG. 1B is a schematic cross-sectional view of connecting a negative electrode of the present invention and a lithium electrode. It is the schematic sectional drawing schematically showing another embodiment of the lithium ion secondary battery of the embodiment.
As shown in FIG. 1A, the lithium ion secondary battery 10 includes a positive electrode 11 connected to the positive electrode terminal 11t via the wiring 11a, a negative electrode 13 connected to the negative electrode terminal 13t via the wiring 13a, and an electrolytic solution 15. , Electrolyzing while preventing the lithium ion supply electrode 17 that supplies lithium ions to the positive electrode 11, the negative electrode 13 or the electrolytic solution 15 and the case 19 from direct contact with the positive electrode 11, the negative electrode 13 and the lithium ion supply electrode 17 to cause a short circuit. It is configured to include a separator 14 having a role of passing a liquid, lithium ions, or the like.

Further, inside the case 19, a current control circuit 20 including a switching element 21 for controlling the connection between the lithium ion supply electrode 17 and the positive electrode 11 is provided, and outside the case 19, control for generating a control signal is provided. A signal generation mechanism 30 is provided.
As shown in FIG. 1B, the current control circuit 25 may include a current control circuit 25 that connects the negative electrode 13 and the lithium ion supply electrode 17 via the switching element 27. Although not shown, the current control circuit 25 that connects the negative electrode 13 and the lithium ion supply electrode 17 via the switching element 27 and the current that connects the positive electrode 11 and the lithium ion supply electrode 17 via the switching element 21. Both current control circuits of the control circuit 20 may be provided.

The configuration of the current control circuit 20 is not particularly limited, and may include a switching element and a resistor connected in series with the switching element, and is connected in series with the switching element and the switching element. It may have a diode, but it is desirable to have both a resistor and a diode.

FIG. 2 is a circuit diagram showing a detailed example of the current control circuit 20.
A diode 11d and a resistor 11e are arranged in the wiring 17a connected to the lithium ion supply electrode 17, and are connected to the positive electrode 11 via the switching element 21. As a result, it is possible to prevent a reverse current from flowing through the current control circuit 20 when the potential is reversed due to over-discharging or the like, and the current flowing through the current control circuit 20 can be kept within a preferable range. The current control circuit 25 may also be provided with a diode and a resistor. The resistance value of the resistor is preferably 50Ω to 10kΩ.

The switching element constituting the current control circuit is a magnetic switch, and the control signal generation mechanism provided outside the case of the lithium ion secondary battery is a method of controlling the on / off of the magnetic switch by magnetism. The switching element constituting the current control circuit may be a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal to control the current flowing through the semiconductor element. By doing so, a method of controlling the on / off of the semiconductor element may be used.

As a switching method using a magnetic switch, a conventionally used method is used, for example, a reed switch type switching method in which a reed switch is operated by a magnet, and a Hall effect is used to amplify the Hall voltage generated by a magnetic field. Examples include a method in which the hose element to be detected is used as a switching element, a method in which the resistance of the element is increased by a magnetic field by utilizing the magnetoresistive effect, and the like, and any method may be used.

As the control signal generation mechanism, for example, the connection and insulation of the current control circuit can be controlled by controlling the strength of the magnetic field acting on the switching element by using an electromagnetic coil or a magnet.
Among these, a method of switching by using a reed switch and moving a magnet arranged outside the case closer to or further away from the reed switch is simple and desirable.

Examples of the method using a semiconductor element as the switching element include a method using a switching circuit including a transistor and a method using a switching circuit including a MOS-FET.

FIG. 3 is a circuit diagram showing a switching circuit including a transistor.
The DC component of the current flowing between the positive electrode terminal and the negative electrode terminal can be used for charging / discharging the lithium ion secondary battery, and the AC or pulse component can be used as the control signal.
A capacitor is provided in the wiring between the positive electrode terminal and the negative electrode terminal to cut the DC component, and the control signal from the control signal source 40 is transmitted to the inside of the case through the positive electrode terminal and the negative electrode terminal. Inside the case, control signals in which the DC component is cut by a capacitor are transmitted from the positive electrode terminal and the negative electrode terminal to the current control circuit, respectively. The control signal is connected between the base and the emitter of the transistor, and switching is performed between the collector and the emitter in conjunction with the control signal. The emitter side is directly connected to the lithium electrode and the collector side is connected to the positive electrode, but the current is limited by a resistor.

FIG. 4 is a circuit diagram showing a switching circuit including a MOS-FET.
The DC component of the current flowing between the positive electrode terminal and the negative electrode terminal can be used for charging / discharging the lithium ion secondary battery, and the AC or pulse component can be used as the control signal.
A capacitor is provided in the wiring between the positive electrode terminal and the negative electrode terminal to cut the DC component, and the control signal from the control signal source 50 is transmitted to the inside of the case through the positive electrode terminal and the negative electrode terminal. Inside the case, control signals in which the DC component is cut by a capacitor are transmitted from the positive electrode terminal and the negative electrode terminal to the current control circuit, respectively. The control signal is connected between the gate (G) and the source (S) of the MOS-FET, and switching is performed between the source (S) and the drain (D) in conjunction with the control signal. The source side is directly connected to the lithium electrode and the drain side is connected to the positive electrode, but the current is limited by a resistor. In a switching circuit using a MOS-FET, the control signal charges the gate-source capacitor to obtain a stable gate voltage, so it is easy to switch on regardless of the polarity of the control signal. Can be obtained.
Note that these current control circuits are an example, and any circuit can similarly switch between the dope electrode and the positive electrode or the negative electrode according to a control signal from the outside.

The above-mentioned diode, resistor and switching element may form a circuit by connecting each element, or these elements may be arranged on a substrate and coated with a resin or the like resistant to an electrolytic solution. Often, these elements may be disposed and connected inside a container that is resistant to electrolytes.

FIG. 5 is a schematic cross-sectional view schematically showing another embodiment of the lithium ion secondary battery of the present invention.
In the lithium ion secondary battery shown in FIG. 1, the current control circuit is arranged in the space between the electrode and the case, but in the lithium ion secondary battery 10 shown in FIG. 5, the current control circuit 20 is the case. It may be arranged in a manner attached to the inside of 19.
In this case, the current control circuit 20 can be more easily protected by coating the current control circuit 20 attached to the inside of the case 19 with a resin or the like resistant to the electrolytic solution.
Although not shown in FIG. 5, the current control circuit 20 may be provided with a diode and a resistor in the same manner as the current control circuit shown in FIG. Further, as the current control circuit, as shown in FIG. 5, the positive electrode 11 and the lithium ion supply electrode 17 may be connected to each other via the switching element 21, but the negative electrode 13 and lithium may be configured. It may be configured by a current control circuit that connects the ion supply electrode 17 via a switching element.
The diodes, resistors, and switching elements that make up the current control circuit 20 may be connected to each other as in the case of the above embodiment, and these elements are arranged on the substrate and inside the case 19. In addition to being attached to the electrolytic solution, the elements may be coated with a resin or the like resistant to the electrolytic solution, or these elements may be arranged inside the container resistant to the electrolytic solution and attached to the inside of the case 19.

Next, the members constituting the lithium ion secondary battery of the present invention other than the current control circuit and the control signal generation mechanism will be described.
The configuration of the lithium ion supply electrode is not particularly limited, but for example, a lithium alloy such as lithium metal or lithium aluminum, a stainless steel plate or an aluminum plate is used as a current collector, and silicon, lithium titanate, or olivine are used as active materials. _{iron, Li 3 V 2 (PO 4} ) 3, LixV 2 that O ₃ such as a lithium-containing compound containing lithium element and one or two or more transition metal elements was applied to the current collector plate, a lithium-ion graphite Examples include those pre-doped with.

Although detailed configurations are omitted in FIG. 1, the positive electrode 11 and the negative electrode 13 are composed of a current collector and an active material layer arranged on one surface or both sides of the current collector.

The positive electrode active material used for the positive electrode is not particularly limited, but _{Li MnO 2} , Li _x Mn ₂ O ₄ (0 <x <2), Li ₂ MnO ₃ , Li _x Mn _1.5 Ni _0.5 O ₄ ( Lithium manganate having a layered structure such as 0 <x <2) or lithium manganate having a spinel structure; LiCoO ₂ , LiNiO ₂ or a part of these transition metals replaced with another metal; LiNi _1/3 Lithium transition metal oxides in which specific transition metals such as Co _1/3 Mn _1/3 O ₂ do not exceed half; these lithium transition metal oxides in excess of Li than their chemical composition; LiFePO ₄ Those having an olivine structure such as, etc. can be mentioned.
In addition, some of these metal oxides are made of aluminum, iron, phosphorus, titanium, silicon, lead, tin, indium, bismuth, silver, barium, calcium, mercury, palladium, platinum, tellurium, zirconium, zinc, lantern, etc. Substituted materials can also be used. In particular, Li _α Ni _β Co _γ Al _δ O ₂ (1 ≦ α ≦ 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. As the positive electrode active material, one type may be used alone, or two or more types may be used in combination.

When the positive electrode active material is used as the positive electrode, the positive electrode active material layer containing the positive electrode active material may be formed into a plate shape and used as it is, or the positive electrode active material containing the positive electrode active material particles on the surface of the current collector. A material layer may be formed to serve as a positive electrode. The average particle size of the positive electrode active material particles in the latter form is not particularly limited, but is preferably 1 to 100 μm, more preferably 1 to 20 μm from the viewpoint of increasing the capacity of the positive electrode active material, reactivity, and cycle durability. Is. Within such a range, the secondary battery can suppress an increase in the internal resistance of the battery during charging / discharging under high output conditions, and can take out a sufficient current. When the positive electrode active material is a secondary particle, it is desirable that the average particle size of the primary particles constituting the secondary particle is in the range of 10 nm to 1 μm, but in the present invention, it is not necessarily in the above range. It is not limited to. However, although it depends on the production method, it is needless to say that the positive electrode active material does not have to be secondary particles due to aggregation, lumpiness, or the like. As the particle size of the positive electrode active material and the particle size of the primary particles, the median diameter obtained by using the laser diffraction method can be used. The shape of the positive electrode active material particles differs depending on the type, manufacturing method, etc., and includes, for example, spherical (powder), plate, needle, columnar, and square, but is limited to these. Any shape can be used without any problem. Preferably, it is desirable to appropriately select the optimum shape that can improve the battery characteristics such as charge / discharge characteristics.

The negative electrode active material used for the negative electrode is not particularly limited as long as it can reversibly store and release lithium, but examples of the negative electrode active material include metals such as Si and Sn, TiO, Ti ₂ O ₃ , and so on. TiO ₂ or _SiO 2, SiO, a metal oxide such as _{SnO 2, Li 4/3 Ti} 5/3 O 4 or _Li 7 composite oxide of lithium and transition metals such as MnN, Li-Pb alloy, Li- Examples thereof include Al-based alloys, Li, and carbon materials such as natural graphite, artificial graphite, carbon black, activated carbon, carbon fiber, coke, soft carbon, and hard carbon. Of these, by using an element that alloys with lithium, it is possible to obtain a battery having a high energy density, a high capacity, and excellent output characteristics as compared with a conventional carbon-based material. The negative electrode active material may be used alone or in combination of two or more. The elements that alloy with lithium are not limited to the following, but are, for example, Si, Ge, Sn, Pb, Al, In, Zn, H, Ca, Sr, Ba, Ru, Rh, Ir. , Pd, Pt, Ag, Au, Cd, Hg, Ga, Tl, C, N, Sb, Bi, O, S, Se, Te, Cl and the like.

Among the above active materials, a carbon material and / or an active material containing at least one element selected from the group consisting of Si, Ge, Sn, Pb, Al, In and Zn are preferable, and the carbon material and Si are preferable. Or, those containing an element of Sn are more preferable.

The current collector constituting the negative electrode or the positive electrode is made of a conductive material, and an active material layer is arranged on one surface or both surfaces thereof. The material constituting the current collector is not particularly limited, and for example, a metal, a conductive polymer material, a conductive resin in which a conductive filler is added to a non-conductive polymer material, or the like can be used.

Examples of the metal include aluminum, nickel, iron, stainless steel, titanium, copper and the like. In addition to these, a clad material of nickel and aluminum, a clad material of copper and aluminum, or a plating material of a combination of these metals is preferable. Further, the foil may be a metal surface coated with aluminum. Of these, aluminum, stainless steel, copper and the like are preferable from the viewpoint of conductivity and battery operating potential.

Examples of the conductive polymer material include polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyphenylene vinylene, polyacrylonitrile, and polyoxadiazole. Since such a conductive polymer material has sufficient conductivity without adding a conductive filler, it is advantageous in terms of facilitating the manufacturing process or reducing the weight of the current collector.

Examples of the non-conductive polymer material include polyethylene (PE; high density polyethylene (HDPE), low density polyethylene (LDPE)), polypropylene (PP), polyethylene terephthalate (PET), polyether nitrile (PEN), and polyimide (PEN). PI), Polyethyleneimide (PAI), Polyethylene (PA), Polytetrafluoroethylene (PTFE), Styrene-butadiene rubber (SBR), Polyacrylonitrile (PAN), Polymethylacrylate (PMA), Polymethylmethacrylate (PMMA), Examples thereof include polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), polystyrene (PS) and the like.

A conductive filler may be added to the above-mentioned conductive polymer material or non-conductive polymer material, if necessary. In particular, when the resin used as the base material of the current collector is composed of only a non-conductive polymer, it is necessary to add a conductive filler in order to impart conductivity to the resin. The conductive filler can be used without particular limitation as long as it is a conductive substance. For example, as a material having excellent conductivity, potential resistance, or lithium ion blocking property, metal, conductive carbon, and the like can be mentioned. The metal is not particularly limited, but at least one metal selected from the group consisting of Ni, Ti, Al, Cu, Pt, Fe, Cr, Sn, Zn, In, Sb, and K, or at least one of these metals. It preferably contains an alloy or metal oxide containing. The conductive carbon is not particularly limited, but is selected from the group consisting of acetylene black, vulcan, black pearl, carbon nanofiber, ketjen black, carbon nanotube, carbon nanohorn, carbon nanoballoon, and fullerene at least. It is preferable to include one type. The amount of the conductive filler added is not particularly limited as long as it can impart sufficient conductivity to the current collector, but is generally about 5 to 35% by mass.

The electrolytic solution is not particularly limited, but a solution in which a metal salt is dissolved as an electrolyte in a solvent can be used.
As the solvent, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC). ), Chain carbonates such as dipropyl carbonate (DPC), aliphatic carboxylic acid esters such as methyl formate, methyl acetate, ethyl propionate, γ-lactones such as γ-butyrolactone, 1,2-diethoxyethane. (DEE), chain ethers such as ethoxymethoxyethane (EME), cyclic ethers such as tetrahydrofuran and 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylformamide, acetonitrile, propylnitrile, Nitromethane, ethyl monoglime, phosphate triester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, Examples thereof include aproton organic solvents such as ethyl ether, 1,3-propanesulton, anisole, N-methylpyrrolidone, and fluorinated carboxylic acid esters.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

The metal salt is not particularly limited, but a lithium salt, a sodium salt, a calcium salt, a magnesium salt and the like can be used.
When a lithium salt is used as the metal salt, the lithium salt includes LiPF ₆ , _{LiAsF 6} , LiAlCl ₄ , LiClO ₄ , LiBF ₄ , LiSbF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ CO ₃ , LiC (CF ₃ SO). ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiB ₁₀ Cl ₁₀ , lower aliphatic lithium carboxylate, lithium chloroborane, lithium tetraphenylborate, LiBr, LiI, LiSCN , LiCl, imides and the like.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

In the above-mentioned lithium ion secondary battery of the present invention, the material of the separator is not particularly limited, and for example, a porous film such as polypropylene or polyethylene or a non-woven fabric can be used. Further, as the separator, one in which they are laminated can also be used. Further, polyimide, polyamide-imide, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), cellulose, and glass fiber having high heat resistance can also be used. It is also possible to use a woven fabric separator in which these fibers are bundled into a thread to form a woven fabric.

As the case constituting the lithium ion secondary battery of the present invention, conventionally used materials can be used, and examples thereof include a case made of an aluminum alloy provided with an explosion-proof safety valve, a case made of a nickel-plated steel plate, and the like. ..

The binder is added for the purpose of binding the constituent members in the active material layer or the active material layer and the current collector to maintain the electrode structure. The binder is not particularly limited, and examples thereof include synthetic rubber binders such as polyvinylidene fluoride (PVdF), polyimide, PTFE, and SBR.

The current control circuit of the present invention is a current control circuit that controls the connection between the lithium ion supply electrode that supplies the lithium ions and the positive electrode or the negative electrode in the lithium ion secondary battery having the above configuration, and has a switching element. However, the switching element is characterized in that it operates based on a control signal transmitted from the outside of the case.
Since this current control circuit has been described in detail in the above description of the lithium ion secondary battery of the present invention, the detailed description thereof will be omitted here.

The capacity recovery method of the lithium ion secondary battery of the present invention is the above-mentioned capacity recovery method of the lithium ion secondary battery.
By generating a control signal from the control signal generation mechanism, the lithium ion supply electrode and the positive electrode or the negative electrode are connected via the switching element, and before charging / discharging or at a predetermined time within the charging / discharging period. It is characterized in that lithium ions are supplied from the lithium ion supply electrode to the positive electrode, the negative electrode or the electrolytic solution to recover the capacity of the lithium ion secondary battery.

Since the configuration of the lithium ion secondary battery of the present invention has been described above, a capacity recovery method using the lithium ion secondary battery will be described here.

First, before starting charging / discharging of the lithium ion secondary battery, a current control circuit and a control signal generation mechanism are used, and for example, by connecting the lithium ion supply electrode to the positive electrode or the negative electrode, lithium ions can be positive or negative. By supplying to the electrolytic solution, the shortage of lithium ions captured by the negative electrode or positive electrode can be compensated for, the initial irreversible capacity can be eliminated, and the initial battery capacity is increased from the standard value. Can be made to.

When the capacity is reduced by repeating the charging and discharging, for example, by connecting the lithium ion supply electrode and the positive electrode or the negative electrode at a predetermined time by using the current control circuit and the control signal generation mechanism, the positive electrode, Lithium ions can be supplied to the negative electrode or the electrolytic solution, and the capacity reduced by repeated charging and discharging can be recovered. The capacity recovery process for the capacity decrease due to repeated charging and discharging can be performed a plurality of times. For example, when a lithium ion secondary battery is mounted on a vehicle, the capacity recovery process is performed at the time of periodic inspection or the like. Therefore, it is possible to extend the mileage that can be traveled with one charge.

10 Lithium ion secondary battery 11 Positive electrode 11a, 13a, 17a Wiring 11t Positive electrode terminal 11d Diode 11e Resistor 13 Negative electrode 13t Negative electrode terminal 14 Separator 15 Electrolyte 17 Lithium ion supply electrode 19 Case 20, 25 Current control circuit 21, 27 Switching element 30 Control signal generation mechanism 40, 50 Control signal source

Claims (11)

Lithium ion having a positive electrode connected to a positive electrode terminal, a negative electrode connected to a negative electrode terminal, an electrolytic solution, a lithium ion supply electrode for supplying lithium ions to the positive electrode, the negative electrode or the electrolytic solution, and a case. It ’s a secondary battery,
A current control circuit including a switching element for controlling the connection between the lithium ion supply electrode and the positive electrode or the negative electrode is provided inside the case, and a control signal for generating a control signal is generated outside the case. Equipped with a mechanism
The switching element is a lithium ion secondary battery characterized in that it operates based on a control signal from the control signal generation mechanism. The lithium ion secondary battery according to claim 1, wherein the current control circuit includes the switching element and a resistor connected in series with the switching element. The lithium ion secondary battery according to claim 1 or 2, wherein the current control circuit includes the switching element and a diode connected in series with the switching element. The lithium ion secondary battery according to any one of claims 1 to 3, wherein the switching element is a magnetic switch, and the control signal generation mechanism magnetically controls on / off of the magnetic switch. .. The switching element is a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal, and controls the current flowing through the semiconductor element to control the on / off of the semiconductor element. The lithium ion secondary battery according to any one of claims 1 to 3, wherein the lithium ion secondary battery is used. Lithium ion having a positive electrode connected to a positive electrode terminal, a negative electrode connected to a negative electrode terminal, an electrolytic solution, a lithium ion supply electrode for supplying lithium ions to the positive electrode, the negative electrode or the electrolytic solution, and a case. A current control circuit that controls the connection between the lithium ion supply electrode that supplies the lithium ions in the secondary battery and the positive electrode or the negative electrode.
The current control circuit is arranged inside the case and has a switching element.
The switching element is a current control circuit that operates based on a control signal transmitted from the outside of the case. The current control circuit according to claim 6, wherein the current control circuit includes the switching element and a resistor connected in series with the switching element. The current control circuit according to claim 6 or 7, wherein the current control circuit includes the switching element and a diode connected in series with the switching element. The switching element is a magnetic switch, and the control signal generation mechanism generates a magnetic control signal and controls an on / off control by controlling a current input to the magnetic switch. 8. The current control circuit according to any one of 8. The switching element is a semiconductor element, and the control signal generation mechanism generates a pulse or AC control signal between the positive electrode terminal and the negative electrode terminal, and controls the current flowing through the semiconductor element to control the on / off of the semiconductor element. The current control circuit according to any one of claims 6 to 8, wherein the current control circuit is performed. The method for recovering the capacity of a lithium ion secondary battery according to any one of claims 1 to 5.
By generating a control signal from the control signal generation mechanism, the lithium ion supply electrode and the positive electrode or the negative electrode are connected via the switching element, and before charging / discharging or at a predetermined time within the charging / discharging period. A method for recovering the capacity of a lithium ion secondary battery, which comprises supplying lithium ions from a lithium ion supply electrode to the positive electrode, the negative electrode, or an electrolytic solution to recover the capacity of the lithium ion secondary battery.

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