WO2020137912A1 - Secondary battery - Google Patents

Abstract

A secondary battery (100) according to the present invention comprises a first electrode (10) and a second electrode (20); and a film-like first resin sheet (31) and/or a film-like second resin sheet (32) that contains a solid electrolyte is arranged between the electrodes (10, 20).

Description

Secondary battery

The present invention relates to a secondary battery.

ㆍBatteries convert the chemical energy of the chemical substances inside to electrical energy by an electrochemical redox reaction. In recent years, batteries have been widely used around the world, mainly in portable electronic devices such as electronic devices, communication devices, and computers. Further, batteries are expected to be put to practical use as mobile devices such as electric vehicles and large-scale devices such as stationary batteries such as power load leveling systems in the future, and they are becoming increasingly important key devices.

Among the batteries, lithium-ion secondary batteries are now widely used. A general lithium-ion secondary battery includes a positive electrode using a lithium-containing transition metal composite oxide as an active material and a material capable of inserting and extracting lithium ions (for example, lithium metal, lithium alloy, metal oxide or It has a negative electrode using carbon as an active material, a non-aqueous electrolyte, and a separator.

However, conventional lithium-ion secondary batteries have limitations in output and capacity per unit weight, and new secondary batteries are expected.

JP2015-002167A discloses that a high capacity and a high output, which cannot be obtained by a conventional lithium ion secondary battery, can be obtained. However, with the spread of electric vehicles, high input and quick charging performance are further improved. Expected to let. Further, the battery of the embodiment disclosed in JP2015-002167A can be confirmed to have a life of about 5000 cycles, but further life performance is required for the spread of next-generation mobility including electric vehicles, smart grids, humanoid robots, and drones. It is expected to improve. In addition, a lithium ion battery using a non-aqueous electrolytic solution or a petroleum solvent has a great safety problem, which is a factor that makes it difficult to spread in mobility including automobiles.

An object of the present invention is to provide a novel and highly safe secondary battery that can realize both long life, high output/input and high capacity.

A secondary battery according to an embodiment of the present invention has a first electrode and a second electrode, and a film-shaped first resin sheet or a film-shaped second resin sheet containing a solid electrolyte is It is configured between both electrodes.

In a secondary battery according to an embodiment, the first electrode contains at least nickel oxide, and the second electrode contains at least graphite, graphene, and silicon.

In the secondary battery according to an embodiment, the first resin sheet contains at least lithium niobate.

In the secondary battery according to an embodiment, the weight ratio of the resin of the first resin sheet and lithium niobate is in the following range.
20/100 <lithium niobate/resin <110/100

In the secondary battery according to an embodiment, the solid electrolyte has a perovskite structure.

In the secondary battery according to an embodiment, the solid electrolyte having a perovskite structure is LiBH4.

In the secondary battery according to an embodiment, the resin material of the first resin sheet and the second resin sheet is acrylic resin.

A secondary battery according to an embodiment has a first resin sheet attached to a positive electrode and a second resin sheet attached to a negative electrode.

A secondary battery according to an embodiment has a first electrode and a second electrode, while a lithium ion battery does not have a separator that is conventionally used and a battery made of a film-like electrolyte has a second electrode. Includes a silicon-containing material having a particle size of at least 30 to 200 nm, and includes multilayer graphene, a graphite material, and a binder.

A secondary battery according to an embodiment is not a configuration in which an all-solid battery holds a solid electrolyte powder between a first electrode and a second electrode, but a film in which a solid electrolyte is dispersed in an acrylic resin having as few side chains as possible. Is sandwiched between the first electrode and the second electrode.

A secondary battery according to an embodiment has a structure in which a film-like sheet containing a solid electrolyte as an electrolyte is formed on a negative electrode, and a resin film containing lithium niobate is formed on a positive electrode.

In a secondary battery according to an embodiment, a solid electrolyte contains hydrogen and elemental boron.

A secondary battery according to an embodiment has a mechanism in which a silicon-containing substance expands during charging and an external force is applied to the perovskite layer, whereby a power storage mechanism is developed.

In the secondary battery according to an embodiment, the resin content of the solid electrolyte film sheet is 50% by weight or more.

In a secondary battery according to an embodiment, a film-like sheet formed on a positive electrode contains a polymer having an acrylic group.

In the secondary battery according to an embodiment, the resin content of the film-like sheet containing the lithium niobate powder formed on the surface of the first electrode is 50% by weight or more.

A secondary battery according to an embodiment has a film having tackiness on the surface of a film-like sheet.

In the secondary battery according to an embodiment, the first electrode is made of a material containing at least lithium and nickel.

According to the present invention, it is possible to provide a highly safe secondary battery which has a long life and can realize high output/input and high capacity. At the same time, it is possible to reduce the process cost and provide an all-solid-state battery with excellent versatility and mass productivity.

It is a schematic diagram of the secondary battery which concerns on embodiment of this invention.

Hereinafter, a secondary battery according to an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.

FIG. 1 shows a schematic diagram of the secondary battery 100 of this embodiment. The secondary battery 100 includes an electrode 10, an electrode 20, and a hole transmitting member 30 that transmits a hole. The hole transmission member 30 may be composed of one layer or two or more layers. The electrode 10 faces the electrode 20 via the hole transfer member 30, and the electrode 10 does not physically contact the electrode 20 due to the hole transfer member 30.

Here, the electrode (first electrode) 10 functions as a positive electrode, and the electrode (second electrode) 20 functions as a negative electrode. When discharging, the potential of the electrode 10 is higher than the potential of the electrode 20, and current flows from the electrode 10 to the electrode 20 via an external load (not shown). When charging, the high potential terminal of the external power supply (not shown) is electrically connected to the electrode 10, and the low potential terminal of the external power supply (not shown) is electrically connected to the electrode 20. Further, here, the electrode 10 is in contact with the current collector (first current collector) 110 to form a positive electrode, and the electrode 20 is in contact with the current collector (second current collector) 120 to be the negative electrode. Is forming.

The hole transmission member 30 is in contact with the electrodes 10 and 20. The hole transmission member 30 may be located in a hole provided so as to connect the electrodes 10 and 20. Alternatively, it may be a non-perforated membrane such as LISICON or NASICON. The hole transfer member 30 includes at least a solid electrolyte material. During discharge, holes generated in the electrode 20 move to the electrode 10 via the hole transfer member 30. On the other hand, during charging, the holes generated in the electrode 10 move to the electrode 20 via the hole transmitting member 30. It is assumed that the potential of the electrode 10 becomes higher than the potential of the electrode 20 due to the movement of the holes from the electrode 10 to the electrode 20, and other mechanism operation can also be assumed. During charging, electrons are imprinted on the electrode 20 to generate a hole in the electrode 10 due to excess cations, and the hole is directed toward the electrode 20 and generated from the electrode 10 on the hole transmitting member 30. It is also possible to cause the holes to collide with each other and dissociate from the material contained in the hole transmitting member 30 that may become the polyvalent cations, transport the polyvalent cations, and cause the polyvalent cations to collide with the electrode 20 to cause the holes. Is. This time, when the hole transfer member 30 is made of a resin film, it is also characterized in that it easily contains high cations, but the polymer material of the resin transfers the holes from the electrode 10 by converting them into radicals. It is a major feature that we have found that we can do it. The holes in the electrode 20 travel in the direction perpendicular to the electric field direction at the electrode 10, and electrons are also accumulated in the direction opposite to the holes. It has now been found that this is a phenomenon caused by graphene used in the electrode 20. At this time, the electrode 10 is a semiconductor material made p-type by doping, and the electrode 20 is a semiconductor material made n-type of the contained silicon. As a result, since holes move faster than ions move, rapid charging can be realized and high input performance can be obtained.

Further, during discharge, a dielectric polarization reaction occurs, electrons stored in the electron storage layer of the electrode 20 are suddenly released from the inside of the electrode to the outside, and holes inside the electrode 20 move to the side of the electrode 10 to provide high output. Tie in with the results you get.

Here, LISICON and NASICON are the following structural materials.
Li _1+x+y Alx(Ti,Ge) _2-x Si _y P _3-y O ₁₂ , Na _1+x Zr ₂ Si _x P _3-x O ₁₂ etc.

It was found that the battery can be obtained by moving the hall in this way. It has been found that this makes it possible to obtain an unprecedentedly high safety, long life, high output/input, and high capacity battery. Further, they have found that a battery can be obtained by utilizing this principle and stacking sheet films. As a result, the process itself has been simplified and the process cost has been greatly reduced compared to the past. In addition, a battery obtained by laminating sheet films can easily be applied to batteries of any size, and since the battery has flexibility that is a feature of the film, a battery that can be applied to any shape can be obtained. Thus, a battery that can be used in a wide range of applications was obtained.

In the secondary battery 100 of this embodiment, the electrode 10 has a p-type semiconductor and the electrode 20 has an n-type semiconductor property. In each case of charging and discharging, the holes move through the hole transmitting member 30.

The hole transmitting member 30 is in contact with the electrodes 10 and 20. Upon discharge, the electrons of the electrode 20 move to the electrode 10 via an external load (not shown) at the same time as being discharged into the hole battery, and the electrode 10 receives the hole via the hole transfer member 30. On the other hand, during charging, the holes of the electrode 10 move to the electrode 20 through the hole transmitting member 30, and the electrode 20 obtains electrons from an external power source (not shown) and the holes from the electrode 10 are generated in the battery. To receive.

⇒We have also found that a battery using holes that operates based on the principle of operation is that the movement of the holes may be offset by the unevenness of the electrode surface, which is a drawback of batteries that use holes. This is because the hole moves straight in a direction perpendicular to the electrode surface, and if there is unevenness, the moving direction of the hole is determined vertically along the unevenness. Therefore, this time, a resin containing a solid electrolyte is provided so that the electrode surface can be smoothed, holes can be moved smoothly, and the battery can have flexibility, and the coating process can be reduced and the process cost can be reduced. We have now found a battery consisting of a film deposited on the surface of an electrode. In addition, they have also found that by utilizing the tackiness of the resin, it is possible to obtain an all-solid-state battery that is strong in an unprecedented vibration test in which electrodes do not shift due to vibration. It was also confirmed that the radicals in the polymer of the resin material transfer holes, and the polymer that becomes an obstacle to trap ions in conventional lithium-ion batteries and all-solid-state lithium-ion batteries has a high performance in this battery system. It was found that it can be promoted.

By this, it was found that the present invention can be effectively expressed and the effect of the present invention which has not been obtained can be obtained.

As described above, in the secondary battery 100 of the present embodiment, the hole generated in the electrode 10 or the electrode 20 moves between the electrode 10 and the electrode 20 via the hole transmitting member 30. Since the holes move between the electrodes 10 and 20 instead of the large form like ions, the secondary battery 100 can efficiently realize a high capacity. Further, in the secondary battery 100 of the present embodiment, the holes move between the electrodes 10 and 20 via the hole transmitting member 30. Since the holes are smaller than the ions and have high mobility, the secondary battery 100 can realize high output and input.

Further, according to the conditions found here, since the hole transfer part 30 has a solid shape and the present battery is not a chemical battery due to a chemical reaction, it is possible to realize high safety, long life, high capacity and high input/output. I got the result.

Table 1 described later also shows the weight energy densities of the secondary battery 100 of the present embodiment and a general lithium ion battery. As will be understood from the above, according to the secondary battery 100 of the present embodiment, it is possible to greatly improve the capacity performance characteristic which has not been obtained in the past.

As described above, the secondary battery 100 of the present embodiment realizes high capacity and high output. The secondary battery 100 of the present embodiment has the characteristics of a semiconductor battery that transmits holes from the electrode 10 that is a p-type semiconductor through the hole transmitting member 30, and the secondary battery 100 is a physical battery (semiconductor battery It can be said to be a battery based on the principle of battery.

The secondary battery 100 according to the present embodiment is a physical battery that does not use an electrolytic solution and does not involve a chemical reaction. Therefore, even if the electrode 10 and the electrode 20 contact each other to cause a short circuit inside, the secondary battery 100 The temperature rise of the battery 100 can be suppressed and it is difficult to catch fire. In addition, the secondary battery 100 of the present embodiment is excellent in cycle characteristics because the capacity is not significantly reduced by rapid discharge.

By using the electrode 20 as an n-type semiconductor in addition to the electrode 10 as a p-type semiconductor, the effect of the present invention can be easily obtained, and the capacity and output characteristics of the secondary battery 100 can be further improved. ..

Whether or not the electrode 10 and the electrode 20 are a p-type semiconductor and an n-type semiconductor can be determined by measuring the Hall effect. Due to the Hall effect, when a magnetic field is applied while flowing a current, a voltage is generated in the direction in which the current flows and the direction perpendicular to the direction in which the magnetic field is applied. Depending on the direction of the voltage, it can be determined whether the semiconductor is a p-type semiconductor or an n-type semiconductor.

[About electrode 10]
The electrode 10 has a composite oxide containing an alkali metal or an alkaline earth metal. For example, the alkali metal is at least one of lithium and sodium, and the alkaline earth metal is magnesium. The composite oxide functions as a positive electrode active material of the secondary battery 100. For example, the electrode 10 is formed from a positive electrode material in which a composite oxide and a positive electrode binder are mixed. Further, a conductive material may be further mixed with the positive electrode material. The composite oxide is not limited to one kind, and may be plural kinds.

The complex oxide includes a p-type complex oxide which is a p-type semiconductor. For example, the p-type composite oxide has lithium and nickel doped with at least one selected from the group consisting of antimony, lead, phosphorus, boron, aluminum and gallium so as to function as a p-type semiconductor. This composite oxide is represented as, for example, Li _x Ni _y M _z Oα. Here, 0<x<3, y+z=1, and 1<α<4. Further, here, M is an element for functioning as a p-type semiconductor, and M is at least one selected from the group consisting of antimony, lead, phosphorus, boron, aluminum and gallium. Alternatively, it is possible that lithium is not contained. Due to the doping, a structural defect is generated in the p-type complex oxide, which causes formation of holes.

For example, the p-type composite oxide preferably contains lithium nickelate doped with a metal element. As an example, the p-type complex oxide is antimony-doped lithium nickel oxide. Alternatively, it is nickel oxide containing no lithium.

For example, as the active material of the electrode 10, lithium nickel oxide, lithium manganese phosphate, lithium manganate, lithium nickel manganese oxide, lithium manganese niobate, and their solid solutions, and their modified products (antimony, aluminum, magnesium, etc.). Eutectic metal) and complex oxides of each material chemically or physically synthesized, and also when lithium is not contained. For example, nickel oxide and manganese oxide are also included.

The electrode 10 is formed of a positive electrode material in which a composite oxide, a positive electrode binder and a conductive material are mixed.

For example, the positive electrode binder is carboxymethylcellulose (CMC), which has a thickening effect, and is mixed with, for example, MAC-350HC manufactured by Nippon Paper Industries Co., Ltd. and modified acrylonitrile rubber (BM-451B manufactured by Nippon Zeon Co., Ltd.). It is made by. As the positive electrode binder, it is preferable to use a binder composed of a polyacrylic acid monomer having an acrylic group (SX9172 manufactured by Nippon Zeon Co., Ltd.). As the conductive agent, acetylene black, Ketjen black, and various types of graphite, graphene, carbon nanotubes, and carbon nanofibers may be used alone or in combination.

By using the above-mentioned materials as the electrode binder, when the secondary battery 100 is assembled, the electrode 10 is less likely to be cracked and the yield can be kept high. It has also been found that the use of a material having an acrylic group as the positive electrode binder reduces the resistance in hole transfer and suppresses the inhibition of the p-type semiconductor property of the electrode 10.

Note that it is preferable that graphene, a perovskite material, or a solid electrolyte material is present in the positive electrode binder having an acrylic group. As a result, the positive electrode binder does not function as a resistor, it becomes difficult to trap electrons and holes, the electrode 10 easily becomes a p-type semiconductor, and heat generation as in a chemical battery is suppressed. Specifically, when graphene, a perovskite material, or a solid electrolyte material is present in the positive electrode binder having an acrylic group, it is difficult to inhibit the hole transfer and promote the formation of a p-type semiconductor. By including these materials, the acrylic resin layer can cover the active material, and it is suppressed that the active material chemically reacts to become an ionic battery, and the battery takes advantage of hole movement as a semiconductor. Further, even in the case of the present battery, the internal resistance of the battery can be kept low, so that the operation of the electrode 20 can be efficiently performed.

Furthermore, the presence of graphene, elemental phosphorus, perovskite material, or solid electrolyte material in the acrylic resin layer relaxes the potential and lowers the oxidation potential reaching the active material, while the holes move without being buffered. it can. Further, the acrylic resin layer has excellent withstand voltage. Therefore, it is possible to form a mechanism in the electrode 10 that can be used at a high voltage and safely realize a high capacity and a high output. Further, since no chemical reaction is involved, the temperature rise at high output is suppressed. This can also improve life and safety. In the case of the present battery as well, the internal resistance of the battery can be similarly reduced, the efficiency is high, the performance is high, and the life can be maintained.

[About electrode 20]
The electrode 20 can store and release ions, holes, and electrons generated in the electrode 10. As the active material of the electrode 20, at least graphite, graphene, and a silicon-containing material are added, and in addition, various natural graphite, artificial graphite, silicon-based composite material (silicide), silicon oxide-based material, titanium alloy-based material, and various alloys The composition materials can be used alone or in combination.

For example, the electrode 20 contains a mixture of graphene and silicon. Further, by adding and dispersing phosphorus oxide and sulfur oxide with a high shearing force dispersing machine (for example, Filmix manufactured by Pramix Co., Ltd.), the electrode 20 becomes an n-type semiconductor in this case. Here, graphene is a nano-level layer with 10 or less layers. Graphene may contain carbon nanotubes (CNTs).

In particular, the electrode 20 preferably contains a mixture of graphite, graphene and silicon or silicon oxide. In this case, the hole storage efficiency of the electrode 20 can be improved, and at the same time, the electron storage layer can be provided. Further, since graphene and silicon oxide do not easily function as heating elements, the safety and life of the secondary battery 100 can be improved.

As described above, the electrode 20 is preferably an n-type semiconductor. The electrode 20 has a substance containing graphene and silicon. The substance containing silicon is, for example, SiOxa (xa<2). Further, by using graphene and/or silicon for the electrode 20, even when an internal short circuit occurs in the secondary battery 100, it is difficult to generate heat, and ignition or rupture of the secondary battery 100 can be suppressed.

Also, the electrode 20 may be doped with a donor. For example, the electrode 20 is doped with a metal element as a donor. The metal element is, for example, an alkali metal or a transition metal. As the alkali metal, for example, any of lithium, sodium and potassium may be doped. Alternatively, the transition metal may be doped with copper, titanium or zinc. Alternatively, phosphorus oxide or sulfur oxide may be used.

The electrode 20 may have graphene doped with lithium. For example, doping of lithium may be performed by adding organic lithium to the material of the electrode 20 and heating it, or by utilizing the collision heat of the substance under high dispersion conditions using the above-described filmics. Alternatively, lithium doping may be performed by attaching lithium metal to the electrode 20. Preferably, the electrode 20 contains lithium-doped graphene or graphite or silicon. In the example, it is shown that a method for doping lithium in the electrode 10 by moving it to the electrode 20 and charging it was found. After doping, lithium does not return to the electrode 10, and lithium is used for doping the electrode 20.

The electrode 20 is formed of a negative electrode material in which a negative electrode active material and a negative electrode binder are mixed. As the negative electrode binder, the same one as the positive electrode binder can be used. A conductive material may be further mixed with the negative electrode material.

[About the hole transmission member 30]
The hole transfer member 30 does not have an electrolytic solution, and has been found to have a film sheet shape this time. The hole transmission member 30 preferably contains an acrylic resin. This is due to the fact that the radical transfer function of acrylic resin efficiently transports holes. In addition, the resin film can prevent the solid electrolyte and the electrolyte from slipping off, which leads to an improvement in resistance to vibration tests and collision tests. Furthermore, it has led to the ability to impart flexibility to the battery.

The hole transfer member 30 is bonded to at least one of the electrode 10 and the electrode 20. Alternatively, they are adhered via an electrolyte. A film containing a substance having a perovskite structure is preferably provided. As a result, we have found that the expansion of silicon during charging exerts pressure on the perovskite layer, which has the function of accelerating the movement of holes, enabling faster charging than ever before.

For example, the hole transmission member 30 has a ceramic material. As an example, the hole transfer member 30 has a porous film layer containing an inorganic oxide filler. For example, the inorganic oxide filler preferably contains alumina (α-Al ₂ O ₃ ) as a main component, and holes move on the surface of alumina. Further, the porous membrane layer may further contain ZrO ₂ —P ₂ O ₅ . Alternatively, as the hole transfer member 30, titanium oxide, silica, LiBH 4, or Li _1+x+y Alx(Ti,Ge) _2-x Si _y P _3-y O ₁₂ may be mixed and used.

A film that carries a ceramic material is used for the hole transmission member 30. The film exhibits voltage resistance and oxidation resistance and low resistance. Further, it is preferable to use a flexible film capable of radical movement in the film that promotes hole movement.

The hole transmitting member 30 preferably also has a function as a so-called separator. The hole transfer member 30 has a composition that can withstand the range of use of the secondary battery 100, and is not particularly limited as long as the semiconductor function of the secondary battery 100 is not lost. As the hole transfer member 30, it is preferable to use a film carrying a perovskite material such as LiBH4 or an oxide solid electrolyte. The thickness of the hole transmitting member 30 is not particularly limited, but it is preferably designed to be 6 μm to 25 μm so as to be within the film thickness that can obtain the designed capacity.

Also, when the above-mentioned material is contained in a polymer in a film form, the weight ratio of the polymer is 50% or more. As a result, the film is easily adsorbed on the electrodes, is less likely to be displaced, and exhibits stable battery performance. In addition, since it has flexibility, a degree of freedom in the form of the battery can be obtained. It has now been found that it becomes easier to secure the bondability of the contained material by adsorbing to the electrode. In the case of a lithium battery, if the amount of polymer is such an amount, ions will be trapped and it will be difficult to secure battery performance.However, in the case of this battery, since it is not an ion but a hole, the hopping phenomenon of the hole is not effective. It has been found that the battery performance can be improved, the vibration test can be endured, and the specifications can be satisfied as a battery for an electric vehicle.

Furthermore, we have found that it is even better to use an acrylic resin that does not have many side chain groups as the polymer material and is easy to transfer radicals, and we have obtained a battery that satisfies the specifications for electric vehicles.

With such a configuration, the battery of various sizes and shapes can be obtained by simply forming a sheet film, and the manufacturing cost of the conventional battery has been significantly reduced.

[Current collectors 110, 120]
For example, the first current collector 110 and the second current collector 120 are formed of stainless steel or nickel foil. Thereby, the potential width can be expanded at low cost.

An example of the present invention will be described below. However, the present invention is not limited to the following examples.

First, let's look at a conventional lithium-ion battery for comparison.

(Comparative Example 1)
Sumitomo 3M Co., Ltd. lithium nickel manganese cobalt oxide BC-618, Kureha Co., Ltd. PVDF#1320 (solid content 12 parts by weight of N-methylpyrrolidone (NMP) solution), and acetylene black in a weight ratio of 3:1:0. At 0.09, the mixture was stirred with a further N-methylpyrrolidone (NMP) in a double-arm kneader to prepare a positive electrode material. A positive electrode material was applied to an aluminum foil having a thickness of 13.3 μm, dried, and then rolled to a total thickness of 155 μm, and then cut into a specific size to form a positive electrode.

On the other hand, artificial graphite, styrene-butadiene copolymer rubber particle binder BM-400B (solid content 40 parts by weight) manufactured by Nippon Zeon Co., Ltd., and carboxymethylcellulose (Carboxymethylcellulose:CMC) in a weight ratio of 100:2.5. A negative electrode material was prepared by agitating with a proper amount of water at a ratio of 1: using a double-arm kneader. A negative electrode material was applied to a copper foil having a thickness of 10 μm, dried, and then rolled to a total thickness of 180 μm, and then cut into a specific size to form a negative electrode.

A polypropylene microporous film having a thickness of 20 μm was sandwiched between the positive electrode and the negative electrode as a separator to form a laminated structure, which was cut into a predetermined size and inserted into a container case. An electrolytic solution in which 1M of LiPF ₆ was dissolved in a mixed solvent in which ethylene carbonate (Ethylene Carbonate: EC), dimethyl carbonate (Dimethyl Carbonate: DMC) and methyl ethyl carbonate (MEC) were mixed in a dry air environment. After being poured into a can and allowed to stand for a certain period of time, it was precharged at a current corresponding to 0.1 C for about 20 minutes and then sealed, to produce a laminated lithium ion secondary battery. After that, the sample was left for aging for a certain period of time in a room temperature environment.

Next, a graphene battery is given as a comparative example.

(Comparative example 2)
A material obtained by doping lithium nickel oxide (manufactured by Sumitomo Metal Mining Co., Ltd.) with 0.7 wt% of antimony (Sb), Li _1.2 MnPO ₄ (Lithiated Metal Phosphate II) manufactured by Dow Chemical Company, and Li ₂ MnO ₃ (Zhenhua). E-Chem Co., Ltd. ZHFL-01) was mixed so that the weight ratios were 54.7%, 18.2% and 18.2% by weight respectively, and AMS-LAB (Hosokawa Micron Co., Ltd.) Mechanofusion) at a rotation speed of 1500 rpm for 3 minutes to prepare an active material of the electrode 10. Next, an active material, acetylene black which is a conductive member, and a binder (SX9172, manufactured by Nippon Zeon Co., Ltd.), which is a polyacrylic acid monomer having an acrylic group, are mixed with N- at a solid content weight ratio of 92:3:5. A positive electrode material was prepared by stirring with methylpyrrolidone (NMP) in a double-arm kneader.

The positive electrode material was applied to a 13 μm thick SUS current collector foil (manufactured by Nippon Steel & Sumikin Materials Co., Ltd.), dried, and then rolled to have an areal density of 26.7 mg/cm ² . After that, it was cut into a specific size to obtain an electrode 10. When the Hall effect of this electrode 10 was measured, it was confirmed that the electrode 10 was a p-type semiconductor.

On the other hand, a graphene material (“xGnP Graphene Nanoplatelets H type” manufactured by XG Sciences, Inc.) and silicon oxide SiO _xa (“SiOx” manufactured by Shanghai Cedar Cedar Co., Ltd.) are used at a weight ratio of 56.4:37.6. And mixed in NOB-130 (Nobilta) manufactured by Hosokawa Micron Co., Ltd. at a rotation speed of 800 rpm for 3 minutes to prepare a negative electrode active material. Next, a negative electrode active material and a negative electrode binder composed of a polyacrylic acid monomer having an acrylic group (SX9172 manufactured by Nippon Zeon Co., Ltd.) were mixed with N-methylpyrrolidone (NMP) at a solid content weight ratio of 95:5. A negative electrode material was produced by stirring with an arm type kneader.

A negative electrode material was applied to a 13 μm-thick SUS current collector foil (manufactured by Nippon Steel & Sumikin Materials Co., Ltd.), dried, and then rolled to have an areal density of 5.2 mg/cm ² . After that, the electrode 20 was formed by cutting into a specific size.

A sheet of 20 μm thick non-woven fabric supporting α-alumina (“Nano X” manufactured by Mitsubishi Paper Mills Ltd.) is sandwiched between the electrodes 10 and 20 to form a laminated structure, and the laminated structure is made into a predetermined size. It was cut and inserted into the battery container. For the non-woven sheet supporting α-alumina, “Novolite EEL-003” (Vinylene Carbonate (VC)) and Lithium bis(oxalato) borate (LiBOB) from Novotechnologies are used. 2% by weight and 1% by weight, respectively) were soaked.

Next, a mixed solvent prepared by mixing EC (ethylene carbonate), DMC (dimethyl carbonate), and EMC (ethyl methyl carbonate) at a volume ratio of 1:1:1 was prepared, and LiPF ₆ was dissolved in 1M in this mixed solvent. An electrolyte was formed. Then, in a dry air environment, inject the electrolytic solution into the battery container and leave it for a certain period of time, then pre-charge it with a current equivalent to 0.1 C for about 20 minutes, then seal and aged for a certain period in a room temperature environment. A secondary battery was produced by leaving it to stand.

Next, the electrodes of Examples 1 and 2 and Comparative Example 3 will be shown, as well as Examples 1, 2 and Comparative Example 3.

The electrode manufacturing method is shown below.

Graphene (Graphene type-R made by XG Sciencess), which is a conductive member, in a material obtained by adding 0.4% by weight of antimony (Sb) (made by High Purity Science) to lithium nickel oxide (made by JFE Mineral Co., Ltd.), and , A binder composed of a polyacrylic acid monomer having an acrylic group (SX9172 manufactured by Nippon Zeon Co., Ltd.) with a solid content weight ratio of 92:3:5 together with N-methylpyrrolidone (NMP) manufactured by Primix Co., Ltd. A positive electrode material was produced by stirring and dispersing with a fill mix which is a mixer.

The positive electrode material was applied to a 13 μm thick SUS current collector foil (manufactured by Nippon Steel & Sumikin Materials Co., Ltd.), dried, and then rolled to have an areal density of 26.7 mg/cm ² . After that, it was cut into a specific size to obtain an electrode 10. When the Hall effect of this electrode 10 was measured, it was confirmed that the electrode 10 was a p-type semiconductor.

On the other hand, graphite with a long axis particle size of 1 to 10 μm (made by Shanghai Sugisugi Technology Co., Ltd.) and silicon with a spherical particle size of 30 to 200nm (Shanghai Sugisugi Technology Co., Ltd.) in a weight ratio of 1:1 NOB-130 (Nobilta) manufactured by 800 rpm for 3 minutes was mixed, and the mixture was mixed with graphene material (“XGnP Graphene Nanoplatelets H type” manufactured by XG Sciences, Inc.) and cmc (MAC350HC manufactured by Nippon Paper Industries Co., Ltd.). And a binder (BM451B, manufactured by Nippon Zeon Co., Ltd.), which is a 1.4% by weight solution of polyacrylic acid monomer, in a weight ratio of 90.8%, 4,32%, 1.96%, 2 After stirring for a fixed time with a dual-arm mixer at a compounding ratio of 0.92, phosphorus pentoxide (manufactured by Kojundo Scientific Laboratory Co., Ltd.) was added to the stirred mixture at a weight ratio of 1:0.005, It was made into a negative electrode paint with FILMIX (manufactured by PRIMIX Corporation).

A negative electrode material was applied to a 13 μm-thick SUS current collector foil (manufactured by Nippon Steel & Sumikin Materials Co., Ltd.), dried, and then rolled to have an areal density of 5.2 mg/cm ² . After that, the electrode 20 was formed by cutting into a specific size.

(Comparative example 3)
In Comparative Example 3, a PbI ₂ solution concentration of 40% dissolved in N,N-dimethylformamide (DMF) was applied to the negative electrode surface of the electrode 20 by microgravure, followed by drying with CH ₃ NH ₃ I in 2-propanol. Then, a solution in which the concentration of 45% was dissolved was coated and dried from above with microgravure, and further, vacuum drying was carried out under reduced pressure of 100 kPa at 105° C. for 72 hours to obtain a battery. It was confirmed by TOF-SIMS and the like that CH ₃ NH ₃ PbI ₃ was formed in a thickness of about 4 to 6 μm on the surface of the negative electrode obtained by this method.

(Example 1)
Acrylic resin material (acrylic monomer) and LiBH4 (lithium borohalide) (Sigma-Aldrich) in a 1:1 weight ratio of a THF 54 wt% solution in a dew point -60°C atmosphere environment was placed on PET. After coating and drying (vacuum drying at 100° C. for 24 hours at −100 kPa) (so that the film thickness after drying becomes 25 μm), a film is formed and peeled off from PET, and this film (second resin sheet) is prepared as described above. The electrode 20 is transferred and set on the negative electrode surface. A battery is obtained by stacking the positive electrode 10 so as to face it. FIG. 1 shows a solid electrolyte film 32 as a second resin sheet. In Example 1, the solid electrolyte film 32 functions as the hole transmitting member 30.

Here, when LiBH4 was formed on the surface of the electrode 20 without being formed into a film, it was confirmed that it reacts with water and emits smoke in an environment where the dew point environment does not reach -60°C. Has also found that even in an environment with a poor dew point, it does not emit smoke and can secure safe and stable batteries. It was also confirmed that the non-film type had a large variation in performance. This is because the directionality of the holes varies due to the unevenness of the electrodes, which causes variations in performance, whereas the one formed into a film can smooth the unevenness of the electrodes due to the film, and the directionality of the holes can be improved. It is believed that the performance stability will be improved because it can be made uniform. It was also found that the film-formed product has flexibility and can be applied to any shape and form. In the case where the film was not formed into a film, the LiBH4 layer was deformed and slipped from the electrode surface or a crack was generated, resulting in deterioration in performance.

Furthermore, it was confirmed that when this film was used instead of the separator of Comparative Example 1, it could not operate as a battery. It is considered that this is because the lithium ion cannot operate when there is a large amount of resin and the resistance component is high.

(Example 2)
Next, in addition to the configuration of Example 1, LiNbO ₃ lithium niobate (manufactured by Sigma-Aldrich) was mixed with an acrylic resin material at a weight ratio of 1:1 to prepare a 53% NMP solution, which was coated on PET. It is made into a film by industrial drying (100°C vacuum drying for 24 hours at -100 kPa vacuum) (so that the film thickness after drying becomes 25 μm), and the film is peeled off from PET, and this film (first resin sheet) is used as the electrode of the positive electrode 10. A battery was formed by transferring and setting it on the surface. FIG. 1 shows a film 31 containing lithium niobate as a first resin sheet. In Example 2, the lithium niobate-containing film 31 and the solid electrolyte film 32 function as the hole transmitting member 30.

The batteries of Example 1, Example 2 and Comparative Examples 1 to 3 produced as described above were evaluated by the method shown below.

(Battery initial capacity evaluation)
The capacity comparison performance of each secondary battery was evaluated with the 1C discharge capacity in the specified potential range 1V to 3.8V of Comparative Example 1 as 100. The shape of the battery was a laminated battery using a square battery can this time. Furthermore, the discharge capacity ratio of 10C/1C was measured. With this, high output performance is evaluated. Similarly, the 10C/1C charge capacity ratio was measured. With this, input performance and quick chargeability are evaluated.

(Nail stick test)
With respect to the fully charged secondary battery, an iron round nail having a diameter of 2.7 mm was penetrated at a speed of 5 mm/sec in a room temperature environment, and the heat generation state and appearance were observed. The results are shown in Table 1 below. In Table 1, the secondary battery in which the temperature and appearance of the secondary battery did not change is indicated as "OK", and the secondary battery in which the temperature and appearance of the secondary battery changed were indicated as "NG". ..

(Overcharge test)
The charge rate was maintained at 200% and the current was maintained, and it was determined whether or not there was a change in appearance for 15 minutes or longer. The results are shown in Table 1 below. In Table 1, a secondary battery that did not cause an abnormality is indicated as “OK”, and a secondary battery that has undergone a change (swelling or rupture) is indicated as “NG”.

(Normal temperature life characteristics)
When the secondary batteries of Example 1, Example 2 and Comparative Example 1 to Comparative Example 3 have a specified potential range of 1V to 3.8V, they are charged at 25° C. at 1C/3.8V and then discharged at 1C/1V. The capacity reduction was compared with the capacity of the first time by performing 3000 cycles and 10,000 cycles.

(Evaluation results)
Table 1 shows the evaluation results described above.

The secondary battery of Comparative Example 1 is a so-called general lithium-ion secondary battery. In the secondary battery of Comparative Example 1, overheating was remarkable after 1 second regardless of the nail piercing speed, whereas in the secondary battery of Example 1, there was almost no temperature increase after nail piercing, which was a significant increase. Was suppressed to. When the battery after the nail penetration test was disassembled and examined, the separator was melted over a wide range in the secondary battery of Comparative Example 1, but the secondary battery of Example 1 had holes due to nail penetration, None of the changes in the morphology of the short circuit (melting, etc.) were observed. Therefore, it was confirmed that even if there was a hole, it could operate as a battery. It goes without saying that this is not possible with batteries such as the conventional lithium-ion batteries. It can be said that this is because the battery using the film-shaped solid electrolyte can maintain the original shape of the film and thus can maintain the battery internal structure even from the impact of nail penetration. It is also considered to be caused by the fact that it is not an ion battery and therefore does not involve a chemical reaction. It can be said that the difference in the life test is due to the cause.

Comparative Example 2 shows a difference from Example 1 in terms of rate performance and life due to the influence of the electrolytic solution. From this, it is shown that the present invention obtains major characteristics that cannot be obtained by the battery using the electrolytic solution.

Comparative Example 3 is a solid-state battery in which a solid is formed on the electrode by coating or the like, and this type of battery has problems particularly in a collision test and a vibration test. When a collision test and a vibration test are performed in accordance with the safety and reliability test standards for small secondary batteries represented by UL and CE, there is no risk of ignition or explosion, but both tests have a 1/5 probability. It is known that the battery loses its function, and when the battery that lost the battery performance was disassembled, it was found that the electrode and the solid electrolyte were slipping off from the current collector.

In batteries for electric vehicles and next-generation mobility, the risk of losing the battery function must be eliminated as much as possible, and as a result of repeated research, the present invention has been achieved. It was revealed that the battery function was not lost in the 100 batteries tested.

In Example 1, it is considered that the solid electrolyte is in the form of a film, the solid electrolyte itself does not collapse due to collision or vibration, and the binding force of the film resin serves as a protective film that also prevents the electrode from collapsing. Up to now, there has been no film-like solid electrolyte, and the solid electrolyte up to now is generally powder-molded or mixed with a small amount of resin and applied. This is because the solid electrolyte traps ions when an insulator is present in an ion battery, which interferes with ion movement and makes it impossible to obtain battery performance. In the present invention, it has been considered that the ratio of the resin as close to 50% by weight is not possible in the ion battery, and there is no film-shaped one in the world. Then, it is considered that the reason why this battery has succeeded is that this battery is a hole transfer battery, and since holes also have a property of jumping over the skeleton of the resin, it is difficult to become an obstacle. With this configuration, we have now obtained that we can stably satisfy the specifications of next-generation mobility such as electric vehicles.

In Example 2, as in Example 1, the solid electrolyte film 31 was provided on the negative electrode 20, and at the same time, the lithium niobate-containing film 32 was provided on the positive electrode 10 side. As a result, as described above, the safety test problem can be solved, and the performance and life are further improved. This is a flat film in which the lithium niobate-containing film smoothes the uneven surface of the positive electrode surface, and the traveling direction disturbed by the unevenness of the positive electrode surface in the moving direction of the hole having a straight traveling property is efficiently directed to the negative electrode direction. I think that it will come. In addition, the radical transfer function in the polymer used for the resin film transports holes, which promotes efficient hole transfer and leads to improved performance. It is also considered that lithium niobate functions as an anchor that improves the ohmic contact between the solid electrolyte and the positive electrode. At the same time, it can be considered that the results also have the effect of preventing the electrodes from shifting in the vibration test. Further, one of the reasons that this structure has the performance of which life is hardly deteriorated. When LiBH4 is used as the solid electrolyte, LiBH4 generally corrodes the positive electrode when not filmed as in this example. However, it is difficult for the LiBH4 component in the film to reach the positive electrode, and in the configuration of Example 2, a protective film is formed on the positive electrode. It is believed that this resulted in a longer life.

In this way, it became a battery with good impact resistance that could not be obtained with conventional ion batteries, and by discovering this feature, we were able to obtain a highly safe, high capacity, high input/output battery.

In Example 2, it was also confirmed that the lithium niobate and the resin were able to obtain this performance when the weight ratio of the lithium niobate and the resin was within the range of 20:100 to 110:100. When the ratio of lithium niobate was less than 20, the internal resistance of the battery became extremely large. At this stage, it is considered that this is because the ohmic contact property between the electrode and the solid electrolyte is deteriorated as described above. After this, I would like to prove it by finding an analysis method. On the contrary, at present, it is difficult to form a film when the proportion of lithium niobate exceeds 110. Further, when the material was applied without being able to form a film, the electrode could not be smoothed, and rather, the unevenness became large, resulting in deterioration in performance. The range is defined from these things.

In addition, in the above-described Example 1, the configuration in which only the solid electrolyte film 32 is provided as the hole transmitting member 30 between the electrodes 10 and 20 has been described. In the second embodiment, the solid electrolyte film 32 is provided on the negative electrode 20 and the lithium niobate-containing film 31 is provided on the positive electrode 10 at the same time, that is, the solid electrolyte film 32 is used as the hole transfer member 30 between the electrodes 10 and 20. The configuration for providing the film 31 containing lithium niobate has been described. Alternatively, only the lithium niobate-containing film 31 may be provided between the electrodes 10 and 20. That is, it is sufficient that at least one of the lithium niobate-containing film 31 and the solid electrolyte film 32 is provided between the electrodes 10 and 20.

Although the embodiment of the present invention has been described above, the above embodiment merely shows a part of the application example of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

This application claims priority based on Japanese Patent Application No. 2018-248140 filed with the Japan Patent Office on December 28, 2018 and Japanese Patent Application No. 2019-22764 filed with the Japanese Patent Office on February 12, 2019. , The entire contents of which are hereby incorporated by reference.

The secondary battery of the present invention can realize high capacity with high output and rapid charging, and is suitably used as a large safe storage battery or the like. For example, the secondary battery of the present invention is preferably used as a storage battery of a power generation mechanism with unstable power generation such as geothermal power generation, wind power generation, solar power generation, hydraulic power generation, and wave power generation. Moreover, the secondary battery of the present invention is also suitably used for a moving body such as an electric vehicle. Furthermore, since it is highly safe, it is widely used in card batteries, mobile phones and mobile terminals.

Claims (8)

A secondary battery having a first electrode and a second electrode, and a film-shaped first resin sheet or a film-shaped second resin sheet containing a solid electrolyte is formed between the electrodes. The secondary battery according to claim 1, wherein the first electrode contains at least nickel oxide, and the second electrode contains at least graphite, graphene, and silicon. The secondary battery according to claim 1 or 2, wherein the first resin sheet contains at least lithium niobate. The secondary battery according to claim 3, wherein the weight ratio of the resin of the first resin sheet and lithium niobate is in the following range.
20/100 <lithium niobate/resin <110/100 The secondary battery according to claim 1, wherein the solid electrolyte has a perovskite structure. The secondary battery according to claim 5, wherein the solid electrolyte having the perovskite structure is LiBH4. The secondary battery according to any one of claims 1 to 6, wherein the resin material of the first resin sheet and the second resin sheet is an acrylic resin. The secondary battery according to any one of claims 1 to 7, wherein the first resin sheet is attached to a positive electrode and the second resin sheet is attached to a negative electrode.

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