JP2008047458A - Electrode for power storage device, and power storage device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for a power storage device for which simple and practical predoping technology can be applied for obtaining of higher capacity by predoping, improvement of energy density with higher voltage and higher output, since the level of demand is high for high energy density and high output/high efficiency charging property in the power storage device, and to provide the power storage device using the electrode for the power storage device. <P>SOLUTION: Electrical conductivity in the electrode is 5.0×10<SP>-2</SP>S/cm or more; and the width of holes going through front and back surfaces of the collector is 0.4 mm or less in the electrode provided with a collector with holes going from the front to back surfaces and an electrode layer, containing active substance formed on the collector in the electrode for the power storage device and the power storage device provided with the electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrode for an electricity storage device having high energy density and high output characteristics, which can be manufactured based on a simple and practical pre-doping technique, and an electricity storage device including the electrode.

  In recent years, midnight power storage systems, home-use distributed power storage systems based on solar power generation technology, and power storage systems for electric vehicles have attracted attention from the viewpoint of effective use of energy aimed at conservation of the global environment and resource saving. Yes. Among them, in a combination of a high-efficiency engine and a power storage system (for example, a hybrid electric vehicle) or a combination of a fuel cell and a power storage system (for example, a fuel cell electric vehicle), the engine or the fuel cell operates at maximum efficiency. Therefore, operation at a constant output is essential, and in order to cope with load-side output fluctuations or energy regeneration, the power storage system side is required to have high output discharge characteristics and high rate charge characteristics. In order to meet this demand, research and development has been carried out in power storage systems to increase the output of lithium ion batteries characterized by high energy density or to increase the energy density of electric double layer capacitors characterized by high output. Yes.

On the other hand, in a power storage device such as a lithium ion battery or a capacitor, attention has been paid to a technology for increasing the capacity and voltage of the power storage device by previously supporting lithium ions on the active material (hereinafter referred to as pre-doping). For example, this pre-doping is applied to a high-capacity material such as an insoluble infusible substrate containing a polyacene-based skeleton structure described in Non-Patent Document 1, Patent Document 1, Non-Patent Document 2, Non-Patent Document 3, etc. Thus, as described in Non-Patent Document 4, it is possible to design an electricity storage device that fully utilizes its characteristics (high capacity). Pre-doping is a technology that has been practically used for a long time. For example, in Non-Patent Document 5 and Patent Document 2, lithium is pre-doped on an insoluble infusible substrate containing a polyacene skeleton structure as a negative electrode active material. A high voltage and high capacity power storage device is disclosed. Regarding pre-doping, a method of incorporating lithium in advance into an electricity storage device using a lithium-supported electrode, a method of mixing lithium metal or the like at the time of electrode formation, and the like are known, but for a simple and practical pre-doping method, an active material There is a method in which a lithium metal foil is brought into contact with an electrode that contains. This technique has a small number of electrodes and is effective for a coin type using relatively thick electrodes. However, the process is complicated in a stacked structure battery or a wound structure battery in which a plurality of thin electrodes are stacked. Alternatively, there are problems in handling thin lithium metal, and a simple and practical pre-doping method is required.

As a method for solving this problem, Patent Document 3 includes a hole penetrating the front and back surfaces, the negative electrode active material can reversibly carry lithium, and the lithium derived from the negative electrode is disposed facing the negative electrode or the positive electrode. An organic electrolyte battery is disclosed which is supported by electrochemical contact with lithium and has an opposing area of lithium of 40% or less of the negative electrode area. In this battery, an electrode layer is formed on a current collector provided with a through hole, and lithium metal and a negative electrode disposed in the battery are short-circuited, so that lithium ions pass through the current collector through-hole, Doped in the negative electrode. In an example of Patent Document 3, an expanded metal is used for a current collector having a through hole, an organic material using an insoluble infusible substrate containing LiCoO _{2 as} a positive electrode active material and a polyacene skeleton structure as a negative electrode active material. An electrolyte battery is disclosed, and the negative electrode active material can be easily pre-doped with lithium ions from lithium metal disposed in the battery. However, the discharge rate of the battery is at the maximum 2C level, and for example, there is no description about output characteristics exceeding 100C.

Patent Document 4 discloses that the use of a current collector having a hole penetrating the front and back surfaces with a porosity of 1% to 30% reduces the dropout of the electrode from the current collector. There is no description about. Patent Document 5 uses an insoluble infusible substrate containing a polyacene skeleton structure having a specific surface area of 1900 m ² / g as a positive electrode, an insoluble infusible substrate containing a polyacene skeleton structure as a negative electrode, and these active materials. A capacitor is disclosed which is formed on a current collector provided with a through hole and pre-doped with lithium ions from a lithium metal disposed in a battery into a negative electrode active material. Although this capacitor voltage exceeds 3.3V and the energy density is about 15 Wh / l, which is higher than that of the conventional capacitor, only the output characteristics up to 50C are disclosed, and the case of using a current collector with a through hole is disclosed. There is no description about the characteristics of the capacitor at high output. Patent Document 6 discloses that by filling a hole of a current collector having a through-hole, it is easy to form an electrode layer and prevent the electrode from falling off, but there is no description regarding output.

As a simple and practical pre-doping method as described above, an electrode layer is formed on a current collector provided with a through hole, and a lithium metal disposed in the battery and a negative electrode are short-circuited, thereby collecting lithium ions. A technique for passing through a through-hole of a body and supporting it on an electrode active material is disclosed. However, for example, when a current collector having a through hole (with a gap) is used at a high output load exceeding 100 C, the capacity is larger than when a current collector such as a metal foil (without a gap) is used. Has the problem of lowering.
T.A. Yamabe, M .; Fujii, S .; Mori, H .; Kinoshita, S .; Yata: Synth. Met. , 145, 31 (2004) JP 59-3806 S. Yata, Y. et al. Hato, K .; Sakurai, T .; Osaki, K .; Tanaka, T .; Yamabe: Synth. Met. , 18, 645 (1987) S. Yata, H .; Kinoshita, M .; Komori, N .; Ando, T .; Kashiwamura, T .; Harada, K .; Tanaka, T .; Yamabe: Synth. Met. 62, 153 (1994) S. Yata, Y. et al. Hato, H .; Kinoshita, N .; Ando, A .; Anekawa, T .; Hashimoto, M .; Yamaguchi, K .; Tanaka, T .; Yamabe: Synth. Met. 73, 273 (1995) Shigeru Yada, Industrial Materials, Vol. 40, no. 5, 32 (1992) JP-A-3-233860 WO98 / 33227 WO00 / 07255 WO03 / 003395 publication WO04 / 097867

  The required level for high energy density and high output / high rate charging characteristics in power storage devices such as lithium ion batteries and capacitors is high. In order to meet this demand, it is considered that high capacity by high-capacity material by lithium pre-doping, or improvement of energy density by high voltage, high output is an essential technology for the future development of electricity storage devices, The above-described pre-doping technique using a current collector having a through-hole is useful in practical application of an electricity storage device that requires pre-doping. However, when this practical pre-doping technology is applied to power storage devices that are characterized by high output characteristics, pre-doping can be carried out easily, but compared to the case where a conventional metal foil is used for the current collector. It is difficult to extract sufficient characteristics at high output load, that is, at high current load. Therefore, the present invention is applicable to a practical pre-doping technique using a current collector having a conventional through hole, and provides an electrode for an electricity storage device excellent in high output load characteristics and an electricity storage device using the same. is there.

The present inventor has conducted research while paying attention to the problems of the prior art as described above, and as a result, an electrode including a current collector having holes penetrating the front and back surfaces and an active material formed on the current collector In the electrode for an electricity storage device having a layer, the electrical conductivity of the electrode is 5.0 × 10 ⁻² S / cm or more, and the width of the hole penetrating the front and back surfaces of the current collector is 0.4 mm or less. As a result, it has been found that the output characteristics expected in the device design can be sufficiently exhibited even under high output load, and the present invention has been completed.

The electrode for an electricity storage device according to claim 1 is an electrode having a current collector having a hole penetrating the front and back surfaces and an electrode layer containing an active material formed on the current collector. 5.0 × 10 ⁻² S / cm or more, and the width of the hole penetrating the front and back surfaces of the current collector is 0.4 mm or less.

  The electrode for an electricity storage device according to claim 2 is characterized in that the porosity of the current collector having holes penetrating the front and back surfaces is 10% or more and 90% or less.

  According to the first or second aspect of the present invention, when this electrode is applied to a conventional practical pre-doping technique, it is possible to sufficiently exhibit output characteristics expected in device design at high output load.

  The electricity storage device according to claim 3 is characterized in that the electrode for electricity storage device described in claim 1 or 2 is used for the positive electrode and / or the negative electrode.

  The electricity storage device according to claim 4 is a positive electrode including a positive electrode active material capable of occluding and releasing lithium, a negative electrode including a negative electrode active material capable of occluding and releasing lithium, and an electrolytic solution in which a lithium salt is dissolved in a non-aqueous solvent. The positive electrode and / or the negative electrode is an electrode according to any one of claims 1 to 3, wherein the positive electrode active material and / or the negative electrode active material is provided with lithium through holes of the current collector. It is characterized by pre-doping by passing.

  According to the third and fourth aspects, a simple and practical pre-doping technique using a current collector having a through-hole can be applied. Further, in the high output load characteristic which is a problem of this technique, an excellent output characteristic is obtained. Can be obtained.

The electrode for an electricity storage device of the present invention is an electrode having a current collector having holes penetrating the front and back surfaces and an electrode layer containing an active material formed on the current collector. 10 ⁻² S / cm or more and the width of the hole penetrating the front and back surfaces of the current collector is 0.4 mm or less. By using this electrode, it is possible to obtain an excellent output characteristic with respect to the high output load characteristic which has been a problem of a simple and practical pre-doping technique using a current collector having a conventional through hole.

  An embodiment of the present invention will be described as follows.

The electrode for an electricity storage device of the present invention is an electrode having a current collector having holes penetrating the front and back surfaces and an electrode layer containing an active material formed on the current collector. The electrode for an electricity storage device is characterized by being 10 ⁻² S / cm or more and a width of a hole penetrating the front and back surfaces of the current collector being 0.4 mm or less.

The current collector having a hole penetrating the front and back surfaces in the present invention is described in Patent Documents 3 to 6, but includes a hole penetrating the front and back surfaces of the current collector. For example, punching, etching, etc. Examples include conductive substrates (such as punching foils, etching foils, and perforated foils) with holes penetrating the front and back surfaces, foamed conductive substrates, conductive material nets, and non-woven fabrics of conductive materials. Further, a punching foil, etching foil or perforated foil of 30 μm or less is preferable. The current collector is made of metal, carbon or the like having high conductivity. For example, the current collector has a conductivity of 10 ⁰ S / cm or more, that is, the electrical conductivity of the electrode of the present invention (5.0 × 10 ⁻² S / cm) having sufficiently high electrical conductivity. The material of the current collector is the voltage / output design of the electricity storage device using the electrode for the electricity storage device of the present invention, the type of active material / conductive material / binder contained in the electrode layer formed on the designed output current collector, or the electrolytic solution In the case of using as a non-aqueous storage device having an electrolytic solution in which a lithium salt is dissolved in a non-aqueous solvent, the positive electrode current collector is made of aluminum, a negative electrode current collector, or the like. As the material, copper is generally used.

The shape of the hole penetrating the front and back surfaces of the present invention is not particularly limited, but various shapes such as a circle, an ellipse, a rectangle, and a polygon are possible as the shape visible on the front surface or the back surface, and the hole passes through the current collector. It is possible to penetrate the current collector front and back surfaces in various shapes such as linear, curved, and three-dimensional.

The porosity of the current collector having holes penetrating the front and back surfaces of the present invention is not particularly limited, but is 10% or more and 90% or less, more preferably more than 30% and 60% or less. In the present invention, the porosity means the volume ratio of holes penetrating the front and back surfaces in the current collector volume. Specifically, the current collector area is A (cm ² ), the current collector thickness is B (cm), the current collector weight is W (g), and the current collector material When the specific gravity ρ (g / cm ³ ) is used, the porosity is “1−W / (A × B × ρ)” × 100%, and in the prior art, this is called the ratio of through-holes, porosity. There is also. This porosity is preferably set large in order to increase the speed of pre-doping or improve the uniformity of pre-doping, but if it is too large, from the viewpoint of ease of electrode layer formation on the current collector and electrode strength It is not preferable.

The width of the hole penetrating the front and back surfaces of the present invention is 0.4 mm or less, more preferably 0.35 mm or less. When the width of the hole is too large, even if the electric conductivity of the electrode satisfies the range of the present invention, it becomes difficult to obtain the high output load characteristic which is the object of the present invention. Moreover, about a minimum, Preferably it is 0.05 mm or more, More preferably, it is 0.1 mm or more, and manufacture of a collector will become difficult when too small. The width of the hole in the present invention refers to the shortest distance from all points in the hole to the current collector, and twice the maximum value is defined as the hole width in the present invention. When the cross section of the hole is a circle, the maximum value of the shortest distance from the point in the hole to the current collector is the radius, and the width of the hole is twice the radius, that is, the diameter. When the cross section of the hole is rectangular, the maximum value of the shortest distance from the point in the hole to the current collector is ½ of the length of the short side, and the width of the hole is the length of the short side of the hole. When the cross section of the hole is elliptical, the maximum value of the shortest distance from the point in the hole to the current collector is the short axis radius, and the width of the hole is the short axis diameter. In the case of an irregular hole, the width of the hole is determined in each cross section as described above, and 80% or more of the width is preferably within the scope of the present invention.

In the electrode for an electricity storage device of the present invention, an electrode layer containing an active material is formed on a current collector having holes penetrating the front and back surfaces. The electrode layer is formed on both sides or one side of the current collector having a through-hole, and can also be formed in the current collector hole. The electrode layer contains an active material as a main component, and can be formed using a conductive material and a binder as necessary. The type of the binder is not particularly limited, and examples thereof include fluorine resins such as polyvinylidene fluoride and polytetrafluoroethylene, and polyolefins such as fluorine rubber, SBR, acrylic resin, polyethylene, and polypropylene. . The amount of the binder is not particularly limited and is appropriately determined depending on the average particle diameter, shape, and the like of the active material. For example, the ratio is preferably about 1 to 30% of the weight of the active material. In addition, the type and amount of the conductive material are not particularly limited, and are appropriately determined depending on the electronic conductivity, average particle size, shape, and the like of the active material. Examples of the material include carbon black and acetylene black. Examples thereof include carbon materials such as graphite and metal materials. The amount of the conductive material is not particularly limited, and an amount necessary for obtaining the electrical conductivity of the electrode described later is added. The electrode for the electricity storage device of the present invention is formed on the current collector using a known electrode molding method such as coating molding, press molding, roll molding, etc., using the above active material, if necessary, a conductive material and a binder. And can be manufactured.

The electric conductivity of the electrode of the present invention is 5.0 × 10 ⁻² S / cm or more, preferably 1.0 × 10 ⁻¹ S / cm or more. This electric conductivity is the electric conductivity in the thickness direction of the electrode. In the present invention, the front and back surfaces of the electrode are sandwiched between cylindrical terminals with a copper radius of 2 mmΦ in the thickness direction, and a pressure of ² kgf / cm ² is applied. It can be determined by measuring the current that flows when a voltage is applied across the terminals. If the electrical conductivity of the electrode is less than the lower limit, the capacity drop is larger than when using a current collector that does not have holes penetrating the front and back surfaces, such as metal foil, at high output load. The effect of the invention cannot be obtained. In addition, the upper limit of the electric conductivity is not particularly limited, and it is better for the purpose of obtaining the effects of the present invention. For example, when the active material powder is molded by the above method, it is usually 1.0 × 10 ¹ S / cm or less.

In order to obtain the electrical conductivity of the electrode of the present invention, as described above, it is common to add a conductive material to the active material and mold the electrode. However, the active material surface is a material having high electrical conductivity. A method such as coating with can also be used. When a conductive material is added, the amount is appropriately determined depending on the electrical conductivity, particle size and shape of the conductive material or the electrical conductivity, particle size and shape of the active material so as to obtain the above-described electrical conductivity. For example, 1 to 50% of the weight of the active material, preferably 5 to 40%, more preferably 10% to 30% can be used. In particular, when the electrical conductivity of the active material is low, or when the particle size of the active material is small, the conductive material may be required 10% or more.

Also, when the contact resistance between the electrode layer and the current collector is large, for example, an electrode layer using an insoluble infusible substrate containing activated carbon or a polyacene skeleton structure as an active material is formed on the current collector made of aluminum. In this case, it is possible to form a thin conductive material layer on the surface of the current collector and form an electrode layer thereon.

When there is no description about the electrode for electrical storage devices of the present invention so far, both the positive electrode and the negative electrode are common. Hereinafter, the active material used for the electrode for an electricity storage device of the present invention will be described separately for a positive electrode and a negative electrode.

In the present invention, the active material for obtaining a positive electrode for an electricity storage device is not particularly limited, but for example, activated carbon, an organic semiconductor such as an insoluble infusible substrate containing a polyacene skeleton structure, and occlusion and release of lithium. Known metal oxides and metal sulfides can be used. Examples of the metal oxide include lithium, such as lithium composite cobalt oxide, lithium composite nickel oxide, lithium composite manganese oxide, or a mixture thereof, and a system in which one or more different metal elements are added to these composite oxides. In addition to metal oxides, metal oxides that can occlude and release lithium such as vanadium pentoxide, manganese dioxide, and molybdenum disulfide but do not contain lithium can also be obtained by pre-doping lithium into the positive electrode or negative electrode in power storage devices. It can be used in the present invention. The particle size of the active material used for these positive electrodes is preferably 2 μm or less, for example, from the output surface.

In the present invention, the thickness of the positive electrode for the electricity storage device (1/2 of the electrode thickness when electrode layers are formed on both sides of the current collector) is appropriately determined depending on the type of active material, the design output of the electricity storage device used, and the like. For example, in the case of an insoluble infusible substrate containing activated carbon or a polyacene skeleton structure, it is preferably 150 μm or less, more preferably 100 μm or less, and when a metal oxide is used, 50 μm or less, 5 μm or more, and further 30 μm or less, 5 μm or more. Is desirable.

In the present invention, the active material for obtaining the negative electrode for an electricity storage device is not particularly limited. For example, activated carbon, an organic semiconductor such as an insoluble infusible substrate containing a polyacene skeleton structure, a graphite material, carbon Examples thereof include materials that can occlude and release lithium, such as series substances, tin oxide, silicon oxide, tin, and silicon. In particular, activated carbon and an insoluble and infusible substrate containing a polyacene skeleton structure are examples of preferable materials because of excellent output characteristics. The particle size of the active material used for these negative electrodes is preferably 2 μm or less, for example, from the output surface.

In the present invention, the thickness of the negative electrode for an electricity storage device (1/2 of the electrode thickness when electrode layers are formed on both sides of the current collector) is appropriately determined depending on the type of active material, the design output of the electricity storage device used, and the like. For example, in the case of an insoluble and infusible substrate containing a polyacene skeleton structure, the thickness is desirably 80 μm or less and 5 μm or more.

The electricity storage device of the present invention is one in which the positive electrode and / or the negative electrode uses the electrode for the electricity storage device, and in particular, a positive electrode containing a positive electrode active material capable of occluding and releasing lithium, and a negative electrode active material capable of occluding and releasing lithium. A positive electrode and / or a negative electrode is an electrode for the electricity storage device, and the positive electrode active material and / or the negative electrode active material has a through-hole of a current collector. It is pre-doped by passing lithium.

The configuration of these electricity storage devices (cell configuration, arrangement of lithium for pre-doping) and the pre-doping method are described in, for example, Patent Documents 3 to 6, but in the present invention, the above-described front and back surfaces are applied to the positive electrode and / or the negative electrode. In an electrode having a current collector having a through-hole and an electrode layer containing an active material formed on the current collector, the electrical conductivity of the electrode is 5.0 × 10 ⁻² S / cm or more, and By using the electrode for an electricity storage device characterized in that the width of the hole penetrating the front and back surfaces of the current collector is 0.4 mm or less, compared to the case where a conventional metal foil is used for the current collector, It is possible to extract sufficient output characteristics at the time of output load, that is, at the time of large current load.

The positive electrode active material capable of inserting and extracting lithium, the negative electrode active material capable of inserting and extracting lithium, the positive electrode, and the negative electrode in the electricity storage device of the present invention are as described above. The electrolytic solution in which the lithium salt used in the electricity storage device of the present invention is dissolved in a non-aqueous solvent is appropriately determined in accordance with the use conditions such as the type of the positive electrode material, the properties of the negative electrode material, and the charging voltage. Examples of the non-aqueous electrolyte containing a lithium salt include lithium salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, γ-butyrolactone, acetic acid. What was melt | dissolved in the organic solvent which consists of 1 type, or 2 or more types, such as methyl and methyl formate, can be used. The concentration of the electrolytic solution is not particularly limited, but generally about 0.5 to 2 mol / l is practical. As a matter of course, it is preferable to use an electrolytic solution having a water content of 100 ppm or less. Moreover, it is also possible to use a well-known gel electrolyte and solid electrolyte.

In the electricity storage device of the present invention, when a separator is disposed between the positive electrode and the negative electrode for the purpose of insulation and electrolyte holding, the separator is not particularly limited, and a polyethylene microporous film, a polypropylene microporous film, Alternatively, there are a laminated film of polyethylene and polypropylene, a woven fabric made of cellulose, glass fiber, aramid fiber, polyacrylonitrile fiber, or a non-woven fabric, which can be appropriately determined according to the purpose and situation.

In the electricity storage device of the present invention, the positive electrode active material and / or the negative electrode active material is pre-doped by passing lithium through the through holes of the current collector from a lithium source such as lithium metal arranged in the electricity storage device. And For example, in an electricity storage device having a structure in which a positive electrode and a negative electrode are sequentially stacked via a separator, a predetermined amount of lithium metal is disposed outside the stacked body, and the lithium metal and the negative electrode are electrically connected. When injected, since the current collector has through holes, lithium can pass through the positive electrode layer, the separator layer, the negative electrode layer, and the current collector, and all negative electrodes are doped. . The same applies to the case where the positive electrode is pre-doped, and the lithium metal and the positive electrode may be electrically connected. It is also possible to pre-dope the electrode active material on both sides of the current collector from one side of the current electrode by forming electrode layers on both sides of the current collector and attaching lithium metal to one side thereof. A current collector having a hole penetrating the front and back surfaces of only the positive electrode or the negative electrode containing the active material may be used.

  The shape of the electricity storage device of the present invention is not particularly limited, and can be appropriately determined according to the purpose, such as a coin shape, a cylindrical shape, a square shape, and a film shape.

  EXAMPLES Examples will be shown below to further clarify the features of the present invention, but the present invention is not limited to the examples.

  (1) 301 g of a cured phenol resin was placed in a stainless steel dish, and the dish was placed in a square furnace (400 × 400 × 400 mm) and subjected to a thermal reaction. The thermal reaction was performed in a nitrogen atmosphere, and the nitrogen flow rate was 5 liters / minute. The thermal reaction was performed at a rate of 1 ° C./minute until the furnace temperature was raised from room temperature to 630 ° C., held at that temperature for 4 hours, then cooled to 60 ° C. by natural cooling, and the dish was removed from the furnace. The insoluble and infusible substrate of the present invention was obtained. The yield was 180g.

  (2) The insoluble and infusible substrate containing the resulting polyacene skeleton structure was pulverized to an average particle size of 5.4 μm using a planetary ball mill. The obtained insoluble and infusible substrate material was subjected to elemental analysis (measurement machine: PerkinElmer elemental analyzer “PE2400 series II, CHNS / O). In the elemental analysis, the atomic ratio of hydrogen atom / carbon atom was It was 0.27.

(3) Next, 66.7 parts by weight of the insoluble infusible substrate containing the above polyacene skeleton structure, 19 parts by weight of conductive material acetylene black, and 14.3 parts by weight of PVdF (polyvinylidene fluoride) were added to NMP (N-methyl). -2-pyrrolidone) was mixed with 230 parts by weight to obtain a negative electrode mixture slurry. This slurry was formed on both sides of a copper punching foil (current collector having through holes of the present invention) having a hole diameter of 0.3 mm (circular and corresponding to the width of the holes in the present invention), a porosity of 50%, and a thickness of 14 μm. After coating, drying, press working was performed to obtain an electrode. The thickness of the electrode was 62 μm, and the density of the electrode layer was 0.79 g / cm ³ . The electrode front and back surfaces of the electrode having electrode layers formed on both sides of the obtained copper punching foil are sandwiched between cylindrical terminals with a diameter of 2 mmΦ made of copper, and a pressure of ² kgf / cm ² is applied between the upper and lower terminals. The current flowing when a voltage of 1 V was applied to the electrode was measured (hereinafter, the electric conductivity was measured by this method), and the electric conductivity of the electrode was determined to be 1.0 × 10 ⁻¹ S / cm.

(4) Lithium metal is arranged on one side of the electrode obtained above, this electrode and lithium metal are electrically connected, and ethylene carbonate and methylethyl carbonate are mixed at an electrolyte ratio of 3: 7 (volume ratio). An electrochemical cell was prepared using a solution of LiPF ₆ dissolved in the solvent at a concentration of 1 mol / l. Using this cell, an amount corresponding to 1000 mAh / g per weight of an insoluble infusible substrate containing a polyacene skeleton structure as an active material was pre-doped. Since lithium metal is disposed only on one side of the electrode, the electrode active material on the opposite side is pre-doped by passing lithium through the through hole.

  (5) 93 parts by weight of commercially available activated carbon, 7 parts by weight of conductive material ketjen black and 17 parts by weight of PVdF were mixed with 355 parts by weight of NMP to obtain a positive electrode mixture slurry. A positive electrode mixture slurry was applied to one side of an aluminum foil having a thickness of 30 μm previously coated with a graphite-based conductive paint, dried, and then pressed to obtain an electrode. In this embodiment, the above-mentioned activated carbon electrode is used for the purpose of evaluating the output characteristics of the electrode formed on the current collector having the through-hole, but the configuration of the electricity storage device of the present invention is not limited.

(6) An electrode layer using an insoluble infusible substrate containing a polyacene-based skeleton structure predoped as described above as an active material and an electrode formed on both sides on a current collector provided with a through-hole is used as a negative electrode. Two activated carbon electrodes having a thickness of 105 μm and an electrode layer density of 0.60 g / cm ³ were used as the positive electrode and arranged on both sides of the negative electrode. An electrochemical cell was prepared using a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 3: 7 as an electrolytic solution.

  (7) The manufactured cell was charged to 4.0 V with a constant current of 500 mA, and then discharged to 2.0 V with a current of 10 mA. The capacity at this time was 9.87 mAh. Subsequently, after the same charging as described above, the output characteristics were confirmed while changing the current density. When discharged with a current of 1 A corresponding to 100 C, the capacity was 6.06 mAh, and when discharged with a current of 3 A corresponding to 300 C, the capacity was 3.41 mAh and discharged with a current of 5 A corresponding to 500 C. In the case, the capacity was 1.63 mAh.

(8) Next, for comparison, 66.7 parts by weight of the insoluble infusible substrate containing the polyacene skeleton structure, 19 parts by weight of conductive material acetylene black, and 14.3 parts by weight of PVdF (polyvinylidene fluoride) are added to NMP. A negative electrode mixture slurry was obtained by mixing with 230 parts by weight of (N-methyl-2-pyrrolidone). This slurry was applied to both sides of a copper foil having a thickness of 14 μm (current collector not having through holes), dried, and then pressed to obtain an electrode. The thickness of the electrode was 61 μm, and the density of the electrode layer was 0.8 g / cm ³ . The electric conductivity of the obtained electrode was determined to be 1.1 × 10 ⁻¹ S / cm.

(9) Lithium metal is arranged on both sides of the electrode obtained above, this electrode and lithium metal are electrically connected, and ethylene carbonate and methyl ethyl carbonate are mixed at 3: 7 (volume ratio) as an electrolytic solution. An electrochemical cell was prepared using a solution of LiPF ₆ dissolved in the solvent at a concentration of 1 mol / l. Using this cell, an amount corresponding to 1000 mAh / g per weight of an insoluble infusible substrate containing a polyacene skeleton structure as an active material was pre-doped.

(10) An electrode in which an electrode layer using an insoluble infusible substrate containing a polyacene skeleton structure pre-doped as described above as an active material is formed on both sides on a current collector having no through hole is used as a negative electrode. Two activated carbon electrodes having a thickness of 106 μm and an electrode layer density of 0.60 g / cm ³ were used as the positive electrode and arranged on both sides of the negative electrode. An electrochemical cell (comparative cell) was prepared using a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 3: 7 as an electrolytic solution.

(11) The prepared comparative cell was similarly charged to 4.0 V with a constant current of 500 mA, and then discharged to 2.0 V with a current of 10 mA. The capacity at this time was 10.0 mAh. Subsequently, after the same charging as described above, the output characteristics were confirmed while changing the current density. When discharged at a current of 1 A corresponding to 100 C, the capacity was 6.57 mAh, and when discharged at a current of 3 A corresponding to 300 C, the capacity was 4.04 mAh and discharged at a current of 5 A corresponding to 500 C. In the case, the capacity was 2.00 mAh. When comparing the characteristics of the above cell using the electrode formed on the current collector having the through-hole of the comparative cell and the present invention, the electrode formed on the current collector having the through-hole was obtained at a current of 10 mA equivalent to 1C. The characteristics of the cell used are 99% of the capacity of the comparative cell (the current collector does not have a through hole), and 93% when discharged at a current of 1A corresponding to 100C, and 300C. Even when a current collector having a through hole is used, 84% even at a current corresponding to 3A, and further 82% even at a current corresponding to 5A corresponding to 500C, the current collector does not have a through hole. Sufficient capacity is obtained even when the output is high with respect to the electrode using the electric body.
(Comparative Example 1)

(1) 66.7 parts by weight of an insoluble infusible substrate containing the polyacene-based skeleton structure described in Example 1, 19 parts by weight of conductive material acetylene black, and 14.3 parts by weight of PVdF (polyvinylidene fluoride) are mixed with NMP ( N-methyl-2-pyrrolidone) was mixed with 230 parts by weight to obtain a negative electrode mixture slurry with the same composition. This slurry was made into a copper punching foil having a hole diameter of 0.5 mm (corresponding to the width of the hole in the present invention), a porosity of 50%, and a thickness of 14 μm. The electrode was applied to both sides of the electric body and dried, followed by pressing to obtain an electrode. The thickness of the electrode was 61 μm, and the density of the electrode layer was 0.80 g / cm ³ . The electric conductivity of the obtained electrode was determined to be 1.0 × 10 ⁻¹ S / cm.

(2) Lithium metal is arranged on one side of the electrode obtained above, this electrode and lithium metal are electrically connected, and ethylene carbonate and methylethyl carbonate are mixed at an electrolyte ratio of 3: 7 (volume ratio). An electrochemical cell was prepared using a solution of LiPF ₆ dissolved in the solvent at a concentration of 1 mol / l. Using this cell, an amount corresponding to 1000 mAh / g per weight of an insoluble infusible substrate containing a polyacene skeleton structure as an active material was pre-doped. Since lithium metal is not disposed on one side of the electrode, the electrode active material on the opposite side is pre-doped by passing lithium through the through hole.

(3) In Example 1, an electrode in which an electrode layer using an insoluble infusible substrate containing a polyacene skeleton structure pre-doped as described above as an active material was formed on both sides on a current collector provided with a through hole was used as a negative electrode. The obtained two activated carbon electrodes having a thickness of 105 μm and an electrode layer density of 0.59 g / cm ³ were used as the positive electrode and arranged on both sides of the negative electrode. An electrochemical cell (comparative cell) was prepared using a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 3: 7 as an electrolytic solution.

(4) Similarly, the fabricated comparative cell was charged to 4.0 V with a constant current of 500 mA, and then discharged to 2.0 V with a current of 10 mA. The capacity at this time was 9.59 mAh. Subsequently, after the same charging as described above, the output characteristics were confirmed while changing the current density. When discharged with a current of 1 A corresponding to 100 C, the capacity was 5.83 mAh, and when discharged with a current of 3 A corresponding to 300 C, the capacity was 3.36 mAh and discharged with a current of 5 A corresponding to 500 C. In the case, the capacity was 1.19 mAh. With a current of 10 mA corresponding to 1 C, the comparative cell described in Example 1 (the current collector does not have a through hole) has a capacity of 96%, and is discharged with a current of 1 A corresponding to 100 C. 89%, 83% at a current of 3A corresponding to 300C, 60% at a current of 5A corresponding to 500C, and the same electrode as the electrode formed on the current collector having the through-hole of Example 1 above. Although it has electrical conductivity (1.0 × 10 ⁻¹ S / cm), the width of the hole passing through the front and back surfaces of the current collector is not 0.4 mm or less. Decreases.
(Comparative Example 2)

(1) As a comparison of the electrical conductivity of the electrodes, 80 parts by weight of the insoluble infusible substrate containing the above polyacene skeleton structure, 10 parts by weight of conductive material acetylene black, and 10 parts by weight of PVdF (polyvinylidene fluoride) are NMP. The mixture was mixed with 230 parts by weight of (N-methyl-2-pyrrolidone) to obtain a negative electrode mixture slurry with the same composition. This slurry was formed on both sides of a copper punching foil (current collector having through holes of the present invention) having a hole diameter of 0.3 mm (circular and corresponding to the width of the holes in the present invention), a porosity of 50%, and a thickness of 14 μm. After coating, drying, press working was performed to obtain an electrode. The thickness of the electrode was 61 μm, and the density of the electrode layer was 0.79 g / cm ³ . The electric conductivity of the obtained electrode was determined to be 2.0 × 10 ⁻² S / cm.

(2) Lithium metal is arranged on one side of the electrode obtained above, this electrode and lithium metal are electrically connected, and ethylene carbonate and methylethyl carbonate are mixed at an electrolyte ratio of 3: 7 (volume ratio). An electrochemical cell was prepared using a solution of LiPF ₆ dissolved in the solvent at a concentration of 1 mol / l. Using this cell, an amount corresponding to 1000 mAh / g per weight of an insoluble infusible substrate containing a polyacene skeleton structure as an active material was pre-doped. Since lithium metal is not disposed on one side of the electrode, the electrode active material on the opposite side is pre-doped by passing lithium through the through hole.

(3) In Example 1, an electrode in which an electrode layer using an insoluble infusible substrate containing a polyacene skeleton structure pre-doped as described above as an active material was formed on both sides on a current collector provided with a through hole was used as a negative electrode. The obtained two activated carbon electrodes having a thickness of 106 μm and an electrode layer density of 0.59 g / cm ³ were used as the positive electrode and arranged on both sides of the negative electrode. An electrochemical cell was prepared using a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 3: 7 as an electrolytic solution.

  (4) The fabricated cell was charged to 4.0 V with a constant current of 500 mA, and then discharged to 2.0 V with a current of 10 mA. The capacity at this time was 9.55 mAh. Subsequently, after the same charging as described above, the output characteristics were confirmed while changing the current density. When discharged at a current of 1 A corresponding to 100 C, the capacity was 5.70 mAh, and when discharged at a current of 3 A corresponding to 300 C, the capacity was 2.32 mAh and discharged at a current of 5 A corresponding to 500 C. In the case, the capacity was 0.25 mAh.

(5) Next, as a comparison, 80 parts by weight of the insoluble infusible substrate containing the above polyacene skeleton structure, 10 parts by weight of conductive material acetylene black and 10 parts by weight of PVdF (polyvinylidene fluoride) were added to NMP (N-methyl). 2-pyrrolidone) was mixed with 230 parts by weight to obtain a negative electrode mixture slurry having the same composition. This slurry was applied to both sides of a copper foil having a thickness of 14 μm (current collector not having through holes), dried, and then pressed to obtain an electrode. The thickness of the electrode was 61 μm, and the density of the electrode layer was 0.79 g / cm ³ . The electric conductivity of the obtained electrode was determined to be 2.2 × 10 ⁻² S / cm.

(6) Lithium metal is arranged on both sides of the electrode obtained above, this electrode and lithium metal are electrically connected, and ethylene carbonate and methyl ethyl carbonate are mixed at 3: 7 (volume ratio) as an electrolytic solution. An electrochemical cell was prepared using a solution of LiPF ₆ dissolved in the solvent at a concentration of 1 mol / l. Using this cell, an amount corresponding to 1000 mAh / g per weight of an insoluble infusible substrate containing a polyacene skeleton structure as an active material was pre-doped.

(7) An electrode in which an electrode layer using an insoluble infusible substrate containing a polyacene skeleton structure predoped as described above as an active material is coated on both sides of a current collector having no through-hole is used as a negative electrode, and The obtained two-sided activated carbon electrodes having a thickness of 104 μm and an electrode layer density of 0.60 g / cm ³ were used as positive electrodes and arranged on both sides of the negative electrode. An electrochemical cell (comparative cell) was prepared using a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / l in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 3: 7 as an electrolytic solution.

(8) The prepared comparative cell was similarly charged to 4.0 V with a constant current of 500 mA, and then discharged to 2.0 V with a current of 10 mA. The capacity at this time was 9.86 mAh. Subsequently, after the same charging as described above, the output characteristics were confirmed while changing the current density. When discharged at a current of 1 A corresponding to 100 C, the capacity was 6.06 mAh, and when discharged at a current of 3 A corresponding to 300 C, the capacity was 3.78 mAh and discharged at a current of 5 A corresponding to 500 C. In the case, the capacity was 0.98 mAh. When comparing the characteristics of this cell using an electrode formed on a current collector having a through-hole and this comparative cell, both of which have an electric conductivity of 2.0 × 10 ⁻² S / cm, equivalent to 1C The characteristics of the cell using the electrode formed on the current collector having a through-hole in the current of 10 mA of the comparison cell (the current collector does not have the through-hole) is 97%, and the capacity is 100C. Is 94% when discharged at a current corresponding to 1A, 61% at a current of 3A corresponding to 300C, and 26% at a current of 5A corresponding to 500C, and the electrical conductivity of the electrode is 5.0 × 10. ^{In the case of −2} S / cm or less, even when the width of the hole penetrating the front and back surfaces of the current collector is 0.4 mm or less, sufficient capacity cannot be obtained at high output load.

The electrode for an electricity storage device and the electricity storage device of the present invention meet the demand for higher energy density and higher output / high rate charging characteristics of a high-output electricity storage device used for, for example, a hybrid electric vehicle, a fuel cell electric vehicle and the like. Yes, it contributes to the increase in the capacity of the electricity storage device by pre-doping, the improvement of the energy density by the increase in voltage, and the increase in output.

Claims (4)

In an electrode having a current collector having holes penetrating the front and back surfaces and an electrode layer containing an active material formed on the current collector, the electrical conductivity of the electrode is 5.0 × 10 ⁻² S / cm or more. And the width | variety of the hole which penetrates the front and back of the collector is 0.4 mm or less, The electrode for electrical storage devices characterized by the above-mentioned.   The electrode for an electricity storage device according to claim 1, wherein the porosity of the current collector having holes penetrating the front and back surfaces is 10% or more and 90% or less.   An electricity storage device comprising a positive electrode, a negative electrode, a separator, and an electrolytic solution, wherein the positive electrode and / or the negative electrode uses the electrode for an electricity storage device according to claim 1 or 2. A positive electrode including a positive electrode active material capable of occluding and releasing lithium, a negative electrode including a negative electrode active material capable of occluding and releasing lithium, and a nonaqueous storage device having an electrolyte solution in which a lithium salt is dissolved in a nonaqueous solvent. Alternatively, the negative electrode is an electrode according to claim 1 or 2, wherein the positive electrode active material and / or the negative electrode active material is pre-doped by passing lithium through the through-hole of the current collector. device.