JP2011166044A - Accumulation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a large-capacity accumulator device by restraining a decrease in lithium ion concentration inside an electrolyte. <P>SOLUTION: In the accumulator device, a siloxane compound is bonded to the surface of a binder for constituting at least one of positive and negative electrode layers, or to the surface of a carbon material particle for composing at least one of the positive and negative electrode layers, thus suppressing reduction in lithium ions, from the inside of an electrolyte and attaining a large-capacity accumulator device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electricity storage device such as a lithium ion secondary battery or an electrochemical capacitor.

  An example of a conventional electricity storage device is a wound electrochemical capacitor. The electrochemical capacitor includes a device in which a pair of positive and negative electrodes each having an electrode layer made of a conductive material and a binder are formed on a current collector made of a metal foil and stacked or wound with a separator interposed therebetween. And an electrolyte containing a lithium salt impregnated in the element as a solute, and a case containing the element together with the electrolyte. The positive electrode and the negative electrode are welded to the terminals, respectively, and are drawn out of the case.

  As prior art document information relating to this application, for example, Patent Document 1 is known.

JP 2008-243888 A

  The capacity of a conventional power storage device may decrease. One possible cause is that lithium ions in the electrolytic solution are combined with binders or carbon material particles in the electrode layer, and the lithium ion concentration in the electrolytic solution is reduced.

  Accordingly, an object of the present invention is to realize a large-capacity electric storage device by suppressing a decrease in the lithium ion concentration in the electrolytic solution.

  In order to achieve this object, the present invention provides a siloxane compound on the surface of the binder constituting at least one of the positive and negative electrode layers, or the carbon material particles constituting at least one of the positive and negative electrodes. Combined.

  In the present invention, a siloxane-treated carboxymethylcellulose layer is provided on the surface of the positive electrode.

  In this way, the present invention allows the binder material, the carbon material particles, or the carboxymethyl cellulose layer as a separator and the siloxane compound to be bonded in advance, so that the reaction between lithium ions in the electrolytic solution and the electrode layer, or in the electrolytic solution. The decrease in the lithium ion concentration due to the reaction between the lithium ion and the electrolyte solvent can be suppressed.

  For example, since the siloxane portion of the binder to which the siloxane compound is bonded has an O atom having an unshared electron pair, the lithium ion in the electrolytic solution is coordinated to the O atom, and the lithium ion is in an ionic state. It can be held stably. By changing the electrode potential, lithium ions can be released into the electrolytic solution.

  As described above, the present invention can suppress the deterioration of the capacity of the electricity storage device by suppressing the decrease in the lithium ion concentration in the electrolytic solution, and can further suppress the occurrence of a fine short circuit due to the reaction product and the change in product resistance. It is.

Partially cutaway perspective view of the electricity storage device of the present invention The perspective view which shows the manufacturing process of the electrical storage device of this invention The figure which shows change with time of product resistance of the electricity storage device

Example 1
Hereinafter, in the first embodiment of the present invention, a configuration will be described by taking a lithium ion capacitor, that is, an electrochemical capacitor 1 as an example of an electricity storage device.

  As shown in FIG. 1, the electrochemical capacitor 1 is obtained by winding a positive electrode 2 and a negative electrode 3 with a separator 4 interposed therebetween. The positive electrode 2 and the negative electrode 3 are impregnated with an electrolytic solution having a lithium salt as a solute. The wound positive electrode 2, negative electrode 3, and separator 4 are accommodated in a case 5. A sealing rubber 6 is inserted into the opening of the case 5, and the opening of the case 5 is sealed with the sealing rubber 6.

  The positive electrode 2 and the negative electrode 3 have current collector layers 7 and 8 that are core materials, respectively, and electrode layers 9 and 10 formed on both surfaces of the current collector layers 7 and 8. The electrode layer 10 of the negative electrode 3 is pre-doped with lithium ions, which can be occluded and desorbed. By pre-doping with lithium ions, the potential of the negative electrode 3 can be lowered and the potential difference between the positive electrode 2 and the negative electrode 3 can be increased.

  In the positive electrode 2 and the negative electrode 3, a part of the electrode layers 9 and 10 is removed, and the positive electrode lead terminal 11 and the negative electrode lead terminal 12 are connected to the exposed current collector layers 7 and 8, respectively. The positive electrode lead terminal 11 and the negative electrode lead terminal 12 are drawn out of the case 5.

  As the binder material constituting the electrode layers 9 and 10 of the electrochemical capacitor 1, carboxymethylcellulose ammonium salt as shown in (Formula 1) is mainly used, and this is kneaded in an aqueous solution and then heated and dried. Carboxymethylcellulose (hereinafter referred to as CMC) remains in the electrode layer 9, and the CMC is separated into the current collector layers 7 and 8 by surrounding the carbon material or conductive material as another constituent member of the electrode layers 9 and 10. It performs the function of holding.

  In this carboxymethyl cellulose, there is a possibility that the carboxyl group part undergoes a dehydration condensation reaction by the Fuchser ester reaction in the presence of hydrogen ions and alcohol, but in the presence of lithium ions, the reaction shown in (Chemical Formula 2) Can occur. In (Chemical Formula 2), lithium ion reacts with the carboxyl group as an acid to produce lithium enolate, and the hydroxyl group of carboxymethylcellulose reacts to cause esterification. When this reaction occurs, lithium ions in the product electrolyte decrease, which affects product characteristics such as capacity reduction and resistance increase.

  In addition, as a material of the binder, a vinyl alcohol copolymer, an allyl alcohol copolymer, a polycarboxylic acid, a carboxyl group-containing copolymer, a vinyl acetate copolymer, etc. composed of a material containing a hydroxyl group, a carboxyl group, and an ester are used. Even in the case of being configured, a reaction similar to (Chemical Formula 2) may occur. Therefore, in the process of manufacturing the electricity storage device such as the electrochemical capacitor 1, the amount of the binder material is modified in advance by using several types of siloxaneation methods described later in the process before housing the element in the case 5. The product characteristics can be improved.

  If the binder material contains a polyamine or aramid skeleton, the reaction with lithium ions is unlikely to occur. However, the lithium ion can be stabilized by modifying the binder using several siloxaneization methods described below. Therefore, it is possible to reduce the opportunity of the reaction of the electrolytic solution with the solvent, suppress the reaction between the lithium ions and the electrolytic solution, and improve the product characteristics.

  A siloxane compound is bonded to the electrode layer 9 and the electrode layer 10 of the positive electrode 2 and the negative electrode 3. Here, lithium ions in the electrolytic solution may be bonded to the electrode layers 9 and 10, but the siloxane compound bonded to the electrode layers 9 and 10 is larger than the total weight of lithium bonded to the CMC. Like that.

  Next, the material of each member of the present embodiment will be described.

  In the positive electrode 2 of this example, the current collector layer 7 is made of an aluminum foil, and the electrode layer 9 is mainly composed of a phenol resin-based activated carbon as a carbon material. In the negative electrode 3, the current collector layer 8 is made of copper foil, and the electrode layer 10 is mainly composed of graphite as a carbon material. Further, the separator 4 is made of cellulose, and the case 5 is made of stainless steel.

Further, as the siloxane compound, polysiloxane in which both ends are epoxy-modified is used in this example. Further, as the electrolytic solution, an electrolytic solution having a lithium salt as a solute, in which the electrolyte cation is lithium ion (Li ⁺ ) and the electrolyte anion is fluorine-containing ion (for example, BF ₄ ⁻ ) was used. As a solvent for this electrolytic solution, a mixed solvent in which ethylene carbonate having a high dielectric constant (hereinafter referred to as EC) and diethyl carbonate having a low viscosity (hereinafter referred to as DEC) were mixed at a weight ratio of 1: 1 was used.

  In this example, aluminum was used as the current collector layer 7 of the positive electrode 2, but other metals such as copper, titanium, niobium, tantalum, nickel, hafnium, zirconium, zinc, tungsten, bismuth, antimony, and magnesium. A foil or a foil of these compounds can be used. Among these, it is particularly preferable to use a metal that forms a nonconductive film by anodic oxidation, that is, aluminum, titanium, niobium, tantalum, nickel, hafnium, zirconium, zinc, tungsten, bismuth, antimony, magnesium, and the like.

  In this example, terminal epoxy-modified polysiloxane was used as the siloxane compound (siloxane agent) that siloxaneizes the binder material of the electrode layer 9 and electrode layer 10, but the hydroxyl group and carboxylic acid of the binder material of the electrode layers 9 and 10 were used. As long as it can react with esters, ammonium salts, and dienes, and by holding siloxane in the electrode layer, lithium ions can be localized in the electrolyte in a stable state. This reduces the opportunity for reaction with lithium ions, suppresses the reaction between lithium ions and the electrolyte, and improves product characteristics. Examples of other siloxane compounds include terminal carboxy-modified polysiloxane, terminal silanol-modified polysiloxane, and terminal amino-modified siloxane.

  Next, the manufacturing method of the electrochemical capacitor 1 of a present Example is demonstrated.

  First, a high-purity aluminum foil (Al: 99.99% or more) having a thickness of 30 μm was electrolytically etched in a hydrochloric acid-based etching solution to roughen the surface, whereby the current collector layer 7 of the positive electrode 2 was formed.

  Next, a phenol resin activated carbon powder having an average particle diameter of 5 μm and carbon black and carboxymethyl cellulose (hereinafter referred to as CMC) having an average particle diameter of 0.05 μm as a conductivity-imparting agent are prepared in a weight ratio of 85: 5: 10. First, a siloxane agent is added to water, stirred and mixed, and after adding acid and heating, carbon black and phenol resin activated carbon powder are sequentially added and kneaded to prepare a paste with a predetermined viscosity. The paste is applied to the front and back surfaces of the current collector layer 7 and dried in the atmosphere at 100 ° C. for 1 hour, then pressed at a linear pressure of 75 to 100 kgf / cm, cut to a predetermined size, and the positive electrode 2 is cut. Obtained.

  Furthermore, a 15 μm thick copper foil was used as the current collector layer 8 of the negative electrode 3, and a 30 μm (one side thickness) graphite electrode layer 10 was formed on the front and back surfaces of the current collector layer 8. This graphite electrode layer 10 was made of graphite: acetylene black: binder = 85: 5: 10, and the binder material was mainly composed of CMC material.

The electrode layer 10 is manufactured by adding CMC to water and stirring and mixing, then adding a siloxane compound, heating after adding an acid, carbon black and graphite are sequentially added and kneaded to obtain a paste having a predetermined viscosity. Then, using a comma coater, a die coater or the like, the current collector layer 8 was coated to a thickness of 50 μm (one side thickness), dried at a temperature of 80 ° C., and then a thickness of 30 μm (one side thickness). Then, a graphite electrode layer 10 having an electrode density of 1.2 to 1.5 g / cm ³ was prepared, and this was cut into a predetermined size to obtain a negative electrode 3.

  An example of the reaction during CMC siloxaneation is shown below.

  As the siloxane compound, for example, a double-end epoxy-modified polysiloxane represented by (Chemical Formula 3) was used. As shown above, CMC is added to water and mixed with stirring. Then, a siloxane agent is added, heated by adding an acid or the like, and the reaction shown in (Chemical Formula 4) or (Chemical Formula 5) is performed. Obtain CMC.

  Alternatively, for example, a carboxy-modified polysiloxane represented by (Chemical Formula 6) shown in (Chemical Formula 6) is used, and CMC is added to water and mixed with stirring. Then, the siloxane compound is added, and an acid is added to heat the mixture. A siloxane-modified CMC is obtained by the reaction shown in Chemical Formula 7).

  Alternatively, as a siloxane compound, for example, it may be carried out by a dehydration condensation reaction shown in (Chemical Formula 9) by heating or adding a catalyst in a state where CMC is immersed in both-end silanol-modified polysiloxane shown in (Chemical Formula 8). It is done. As shown in a part of (Chemical Formula 9), since the dehydration condensation reaction occurs by heating between the silal groups, the addition amount needs attention.

  Alternatively, for example, the amine-modified polysiloxane having both ends shown in (Chemical Formula 10) is used as the siloxane compound, CMC is added to water and mixed with stirring, then the siloxane compound is added, and an acid is added and heated. The reaction shown in 11) is carried out to obtain a silanized CMC.

  The above-mentioned examples of the silanization reaction have shown the case where the binder is CMC. As the binder material, vinyl alcohol copolymer and allyl alcohol copolymer composed of a material containing hydroxyl group, carboxyl group, ester and amine are used. Even in the case of being composed of polycarboxylic acid, carboxyl group-containing copolymer, vinyl acetate copolymer, polyamine copolymer, etc., the binder should be modified by the above-mentioned siloxaneation method in a generally similar manner. As a result, the product characteristics can be improved.

  Moreover, the fall of the density | concentration of the lithium ion in electrolyte solution can be suppressed by making the total weight of the couple | bonded siloxane compound larger than the total weight of the lithium ion couple | bonded with CMC.

  Next, the electrode layer 9 of the positive electrode 2 and the electrode layer 10 of the negative electrode 3 are partially shaved to expose the respective current collector layers 7 and 8. Then, the positive electrode lead terminal 11 is welded to the exposed current collector layer 7 of the positive electrode 2 with a laser. A negative electrode lead terminal 12 is welded to the exposed current collector layer 8 of the negative electrode 3 with a laser.

  Thereafter, the positive electrode 2 and the negative electrode 3 were made into a set of two sheets and wound with the separator 4 interposed between them to form an element. This element was inserted together with the electrolytic solution into the case 5 in which lithium was previously disposed on the inner bottom surface, and the element was impregnated with the electrolytic solution.

  Next, the positive electrode lead terminal 11 and the negative electrode lead terminal 12 drawn out from the element inserted into the case 5 together with the electrolytic solution in this way are passed through the holes provided in the sealing rubber 6, and the sealing rubber 6 is inserted into the case. After being fitted into the opening 5, sealing was performed by drawing and curling the vicinity of the opening end of the case 5, and the electrochemical capacitor 1 according to this example was assembled.

  In this example, the siloxane treatment of the electrode layer 9 of the positive electrode 2 was also performed in the same manner.

  Both the positive and negative electrode layers 9 and 10 may be siloxaneated, or one of them may be siloxaneized.

  As a pre-dope method, which is a step after the electrode layer 10 of the negative electrode 3 is silanized, a method by ion migration shown in FIG. As a method by ion migration, the assembled electrochemical capacitor was pre-doped using a jig 13 as shown in FIG. The jig 13 includes a case holding portion 13a electrically connected to the metal case 5 and a lead terminal holding portion 13b electrically connected to the negative electrode lead terminal 12 drawn from the element. The holding portion 13a and the lead terminal holding portion 13b are electrically connected by being joined by a conducting wire 13c. The jig 13 thus configured is attached to an electrochemical capacitor, and in this state, 3. The pre-doping operation is performed by allowing a predetermined time to elapse while applying a voltage of 05 V or higher. On the other hand, as a method by lithium diffusion, a lithium layer is formed by attaching a lithium foil to the negative electrode surface, etc., and a voltage of 3.05 V or more is applied between the leads without using the jig 13. The pre-dope operation is performed by elapse of time. Through this pre-doping operation, lithium disposed on the inner bottom surface of the case 5 is occluded in the electrode layer 10 of the negative electrode 3 as lithium ions.

  As described above, the electrochemical capacitor 1 of this embodiment can be manufactured.

  Hereinafter, the effect of the present embodiment will be described.

  In this embodiment, it is possible to suppress a decrease in the lithium ion concentration in the electrolytic solution and to suppress the capacity deterioration of the capacitor. Furthermore, it is possible to suppress the occurrence of a fine short circuit due to the reaction product and the change in product resistance.

  This is because a siloxane compound is bonded to the binder material of the positive electrode 2 and the negative electrode 3. That is, since the siloxane compound has O atoms having unshared electron pairs, lithium ions in the electrolytic solution can be coordinated with the O atoms, and the lithium ions can be stably held in an ionic state. When a potential is applied, lithium ions can be released into the electrolytic solution.

  Therefore, this invention can suppress that lithium ion couple | bonds with the binder material of the positive electrode 2 and the negative electrode 3 by coordinating a lithium ion to a siloxane compound. As a result, a reduction in the lithium ion concentration in the electrolytic solution can be suppressed, and a large-capacity capacitor can be realized.

  Here, there is a possibility that the siloxane compound may be slightly combined with the binder material of the positive electrode 2 and the negative electrode 3 only by containing the siloxane compound in the electrolytic solution. Need to bind more than naturally bind. Therefore, in this example, at any time, the weight of the siloxane compound bonded to the binder material of the positive electrode 2 is at least larger than the weight of lithium in the electrolyte solution bonded to the binder material of the positive electrode 2. The siloxane compound bonded to the binder material of the negative electrode 3 is preferably bonded so that the weight of the siloxane compound is greater than that of lithium bonded to the binder material of the negative electrode 3.

  In addition, when most of the sites such as hydroxyl groups that can react with the lithium ion of the binder are silanized, ion migration in the electrode layer is hindered due to steric hindrance, which may increase product resistance. . Therefore, the binder in this example is an electrochemical capacitor using a conventional binder material in which the equilibrium value (resistance value R1 in FIG. 3) of the degradation resistance of the electrochemical capacitor 1 using the binder is not bonded to a siloxane compound. An appropriate amount of a siloxane compound is bonded so as to be smaller than the equilibrium value of the deterioration resistance (resistance value R2 in FIG. 3).

  Here, the deterioration resistance means that the electrolyte solution is sufficient and deteriorates over time due to the reaction between the separator 4, the electrode layers 9 and 10, and each of the electrolyte solution and lithium ions under ideal conditions where the solution does not dry up. The resistance value of the product. The deterioration resistance value of the electrochemical capacitor becomes balanced when a predetermined time is set. In the above description, the resistance value when this equilibrium is achieved is described as the equilibrium value of the degradation resistance.

  That is, as the amount of the siloxane compound in the electrode layers 9 and 10 increases, the initial resistance value increases due to steric hindrance, but the reaction between lithium ions and the electrode layers 9 and 10 and the separator 4 is suppressed, and the resistance value is Almost no increase. Therefore, when the siloxane compound is excessively bonded to the electrode layers 9 and 10, the initial resistance (resistance value R3) of the product is already higher than the average value R2 of the conventional degradation resistance as shown in the comparative example of FIG. However, the effect of suppressing the binding between the electrode layers 9 and 10 and lithium ions cannot be manifested, but if the initial resistance value R1 is lower than the equilibrium value R2 of the conventional degradation resistance as in this embodiment, the steric hindrance The bond between the binder material and lithium ions can be reduced while suppressing the above. As a result, the product resistance can be kept low for a long time.

As described above, in this embodiment, the electrochemical capacitor 1 has been described as an example. However, even in the case of a lithium ion secondary battery, an appropriate amount of a siloxane compound is bonded to the binder material of the negative electrode layer, thereby Since the reaction and the reaction of lithium ions to unnecessary sites of the negative electrode can be suppressed, the reduction of the lithium ion concentration in the electrolytic solution can be suppressed, and a highly reliable lithium ion secondary battery can be realized. . In the case of a lithium ion secondary battery, 10 g of lithium cobaltate (LiCoO ₂ ) powder having an average particle size of about 10 μm as an active material for the positive electrode, 0.3 g of acetylene black as a conductive agent, and polyfluoride as a binder. A positive electrode mixture paste was prepared by thoroughly mixing 0.8 g of vinylidene chloride powder and an appropriate amount of N-methyl-2-pyrrolidone (NMP), and the resulting paste was applied to an aluminum foil having a thickness of 20 μm. Then, after drying, it is rolled to form an active material layer, which is used as a positive electrode and is opposed to the negative electrode.

  In this embodiment, the winding type capacitor has been described as an example. Similarly, when a multilayer capacitor in which a positive electrode and a negative electrode are stacked via a separator is used, a siloxane compound is used as a binder material for the electrode layer. By combining these, a large-capacity capacitor can be realized.

(Example 2)
The main difference between the present example and Example 1 is that the separator 4 is substituted and a silanized binder is applied to the surface of the electrode layer 9 of the positive electrode 2. The siloxane binder formed on the surface of the electrode layer 9 of the positive electrode 2 also serves as the conventional separator 4. The weight of the siloxane compound bonded to the binder material (carboxymethyl cellulose (hereinafter referred to as CMC)) as the separator was set to be larger than the weight of lithium in the electrolyte solution bonded to the binder material.

  As a method for obtaining a siloxane-modified CMC, the above-described material for siloxaneization of CMC and the reaction example are used, and the obtained siloxane-ized CMC paste is applied to the surface of the electrode layer 9 of the positive electrode 2. It is formed by coating and drying.

  This suppresses unnecessary reaction of lithium ions with respect to the positive electrode 2 and the separator 4 and allows the lithium ions to be localized in the electrolyte solution in a stable state. Therefore, an opportunity for reaction with the solvent of the electrolyte solution Can be reduced to suppress the reaction between lithium ions and the electrolyte, thereby improving the product characteristics. In addition, the separator 4 of the electrochemical capacitor 1 as shown in FIG. 1 has conventionally been used with a thickness of several tens of μm. However, in place of the separator 4 of FIG. By forming a layer, it is possible to reduce the thickness, so that the distance between the positive electrode 2 and the negative electrode 3 can be shortened, the product resistance characteristics can be further lowered, and the capacitor characteristics suitable for higher current applications can be exhibited. It can be done.

  Also in this example, as in Example 1, moderate siloxaneization of the CMC layer is preferable. That is, as in Example 1, the initial resistance value R1 of the product is lower than the conventional equilibrium value R2 of the degradation resistance, thereby suppressing the steric hindrance and binding the positive electrode 2 or the CMC layer to the lithium ion. Can be reduced. As a result, the product resistance can be kept low for a long time.

  In addition, as an electrical storage device in a present Example, application with a lithium ion capacitor is realizable.

(Example 3)
In this example, an electrochemical capacitor in which a siloxane compound is bonded to the surfaces of carbon material particles constituting the electrode layers of the positive electrode and the negative electrode to form a siloxane will be described.

  The carbon material particles have a functional group including a hydroxyl group, a carboxyl group, an ester and the like on the surface. These functional groups are formed by using the above reaction to obtain silanized carbon material particles, adding the paste to a kneader in which CMC has already been added, and then sequentially administering electrode materials. .

  The carbon material particles of the positive electrode are made of, for example, phenol resin activated carbon powder or carbon black. The negative electrode and the carbon material particles are made of, for example, graphite or acetylene black.

  In the present embodiment, similarly to the first embodiment, a decrease in the lithium ion concentration in the electrolyte can be suppressed, and a large-capacity electrochemical capacitor 1 can be realized.

  Further, in this embodiment, since the reaction of lithium ions in the electrolyte solution binding to the surface functional groups of the carbon material particles of the electrode layers 9 and 10 can be suppressed, an unnecessary reaction of lithium ions with respect to the electrode layers 9 and 10 Since the decrease in the lithium ion concentration in the electrolyte can be suppressed, the product characteristics can be improved and the life can be extended.

  In order to realize a large capacity, at least the weight of the siloxane compound bonded to the carbon material particles of the positive electrode 2 is larger than the weight of lithium in the electrolytic solution bonded to the carbon material particles of the positive electrode 2. It is preferable to do. Similarly, in the negative electrode 3, the weight of the siloxane compound bonded to the carbon material particles of the negative electrode 3 is preferably larger than the weight of lithium in the electrolyte solution bonded to the carbon material particles of the negative electrode 3.

  Furthermore, moderate siloxaneization is preferable in order to reduce the resistance of the electricity storage device. That is, as in the first embodiment, the initial resistance value R1 of the product is lower than the equilibrium value R2 of the conventional deterioration resistance, so that the binding between the carbon material particles and lithium ions can be reduced while suppressing steric hindrance. . As a result, the product resistance can be kept low for a long time.

  Even in a lithium ion secondary battery, the product characteristics can be improved and the life can be extended by siloxaneizing the carbon material particles of the negative electrode.

Example 4
In this example, the positive electrode 2 and the negative electrode 3 that have been silanized by the method shown in Example 1 or the like are carbonized. The following formula (Chemical Formula 12) shows an example of a reaction in which a silanized CMC is partially carbonized by dehydration of a hydroxyl group. Residual hydroxyl groups that have not reacted with the siloxane compound can be eliminated, the number of hydroxyl groups can be reduced, and the reaction between the unreacted hydroxyl groups and lithium can be suppressed.

  In this embodiment, by suppressing the reaction between lithium ions and hydroxyl groups in the electrolyte, a decrease in lithium ion concentration can be suppressed, and a large-capacity electrochemical capacitor can be realized. Further, since the number of hydroxyl groups is reduced by carbonization of silanized CMC, precipitation of a lithium ion solid product can be further suppressed, and as a result, characteristic deterioration of the electrochemical capacitor can be significantly suppressed.

  Similarly, the negative electrode of the lithium ion secondary battery can be carbonized after silanization to improve the capacity and suppress the deterioration of characteristics.

  The electricity storage device of the present invention can realize a large capacity and low ESR, and is useful in various electronic devices or in-vehicle power supplies.

1 Electrochemical capacitor (electric storage device)
2 Positive electrode (electrode)
3 Negative electrode (electrode)
4 Separator 5 Case 6 Sealing rubber 7 Current collector layer 8 Current collector layer 9 Electrode layer 10 Electrode layer 11 Positive electrode lead terminal 12 Negative electrode lead terminal 13 Jig 13a Case hold unit 13b Lead terminal hold unit 13c Conductor

Claims (6)

An element in which a pair of positive and negative electrodes each having an electrode layer made of a carbon material, a conductive material, and a binder are formed on a current collector made of a metal foil and stacked or wound with a separator interposed therebetween, and this element And a storage case in which a siloxane compound is bonded to a binder that constitutes at least one of the positive and negative electrode layers. device. The electricity storage device according to claim 1, wherein the weight of the siloxane compound bonded to the binder constituting the electrode layer is greater than the weight of lithium ions in the electrolyte solution bound to the binder constituting the electrode layer. The electricity storage device according to claim 1, wherein the binder comprises a polysaccharide or a polysaccharide salt. A siloxane-treated carboxymethylcellulose layer is provided on the surface of a positive electrode in which an electrode layer made of a carbon material, a conductive material and a binder is formed on a current collector made of a metal foil, and a current collector made of a metal foil is provided on the opposite surface. An element obtained by laminating or winding a negative electrode in which an electrode layer made of a conductive material and a binder is formed on an electric body, an electrolytic solution having a lithium salt impregnated in the element as a solute, and the element as the electrolytic solution And a case housed together with the electricity storage device. An element in which a pair of positive and negative electrodes each having an electrode layer made of a carbon material, a conductive material, and a binder are formed on a current collector made of a metal foil and stacked or wound with a separator interposed therebetween, and this element An electrolyte containing a lithium salt impregnated in a solute and a case containing the element together with the electrolyte, and binding a siloxane compound to the surface of at least one of the positive and negative carbon material particles constituting the electrode layer An electricity storage device made up of The electric storage device according to claim 1, wherein at least one of the positive and negative electrodes is carbonized.

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