JP5811034B2 - Non-aqueous power storage device and lithium ion secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous power storage device and a lithium ion secondary battery.

  Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. The electrode assembly that constitutes the secondary battery includes a stacked type and a wound type. In the laminated electrode assembly, a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are alternately laminated with a separator interposed therebetween.

  When a secondary battery is used as a power source for a traveling motor, such as an electric vehicle or a hybrid vehicle, large current charging, large current discharging and large capacity are required. Charging / discharging with a large current is accompanied by large heat generation inside the battery.

  The separator plays a role of ensuring the insulation between the positive electrode and the negative electrode and allowing the movement of ions in the electrolytic solution constituting the secondary battery. Conventionally, as a separator, a microporous film using a general-purpose polymer such as polypropylene (PP) or polyethylene (PE) has been mainly used. However, PP and PE have a low melting point, and the durability tends to decrease due to large heat generation inside the battery due to charging / discharging with a large current. In addition, when the internal short circuit occurs, the microporous film made of PP or PE shrinks due to the short-circuit reaction heat that occurs instantaneously, the area becomes small, and the positive electrode and the negative electrode may be short-circuited.

  In order to enhance heat resistance, a so-called ceramic coat separator having a surface covered with a porous coat layer containing ceramic particles (powder) has been proposed and implemented. In addition, from the viewpoint of preventing contact between the positive electrode and the negative electrode, the flat surfaces of the separator are joined together by heat welding or adhesion to form a bag shape.

  In addition, a separator for obtaining a sealed lead battery having a long charge / discharge cycle life has been proposed as a sealed lead battery separator (see Patent Document 1). The separator of Patent Document 1 is mainly composed of thermoplastic synthetic resin fibers having high heat resistance, and glass fibers having a fiber diameter of 3 μm or less are dispersed in the separator in a range of 10 wt% to 25 wt% of the entire separator. A sheet of felt-like non-woven fabric is folded in half into a U-shape that is large enough to wrap the electrode plate, and the opposite left and right ends are welded to form a bag. Polypropylene fibers are mentioned as thermoplastic synthetic resin fibers having high heat resistance.

Japanese Patent Publication No. 7-60676

  The separator described in Patent Document 1 is made of a felt-like nonwoven fabric in which glass fibers are dispersed mainly with thermoplastic synthetic resin fibers having high heat resistance. However, even though heat resistance is high, since polypropylene has a melting point of about 165 ° C., ultrasonic welding and heat welding are possible. However, in the case of a ceramic coat separator, heat welding or ultrasonic welding cannot be performed.

  The purpose of making the separator into a bag shape is to reduce the man-hours when manufacturing the electrode assembly. More specifically, the number of sheet-like positive electrodes, sheet-like negative electrodes, and separators depends on the capacity of the power storage device (secondary battery), but when used as a vehicle power source, several tens of each are required. . Therefore, when manufacturing an electrode assembly, it is necessary to laminate several dozens of positive electrodes, separators, and negative electrodes alternately without misalignment. On the other hand, when the positive electrode and the negative electrode are accommodated in a bag-shaped separator, the bag-shaped separator in which the positive electrode is accommodated and the bag-shaped separator in which the negative electrode is accommodated may be alternately stacked, which greatly increases the man-hours. To reduce.

  Further, in a state where the electrode assembly is housed in the case of the power storage device (secondary battery) and incorporated in the power storage device, the separator does not necessarily need to maintain a bag shape. The secondary battery manufacturing process includes a process of impregnating the active material applied to the positive electrode and the negative electrode constituting the electrode assembly housed in the battery case with an electrolyte solution. In the case of bonding with an adhesive, it is disadvantageous for the impregnation of the electrolytic solution.

  The present invention has been made in view of the above problems, and its object is to reduce the man-hour when manufacturing an electrode assembly using a ceramic coat separator or a ceramic separator that cannot be thermally welded. An object is to provide a water-based power storage device and a lithium ion secondary battery.

In order to achieve the above object, the invention according to claim 1 is a stacked electrode in which a positive electrode sheet electrode and a negative electrode sheet electrode are stacked with a ceramic separator interposed therebetween. The assembly is a non-aqueous power storage device housed in a case together with an electrolytic solution, wherein the electrolytic solution contains a substance having a melting point of 25 ° C. or higher, and at least one of the positive electrode and the negative electrode Comprises the electrode assembly in a state of being accommodated in a bag-shaped ceramic separator in which the opposing planes of the ceramic separator are joined to each other by the substance, and the substance is ethylene carbonate. The Here, the “ceramic separator” is not limited to a separator made entirely of ceramic, but also includes a ceramic coated separator in which a ceramic layer is formed on both sides of a resin layer, and a separator made of ceramic at least on one side. means.

  In the present invention, at least one of the positive electrode sheet-like electrode and the negative electrode sheet-like electrode constituting the multilayer electrode assembly is configured to be accommodated in a bag-like ceramic separator. To do. Therefore, if both the positive electrode and the negative electrode are accommodated in the bag-shaped ceramic separator, the bag-shaped ceramic separator in which the positive electrode sheet is accommodated and the negative electrode sheet The electrode assembly can be assembled by alternately laminating a predetermined number of the bag-shaped ceramic separators containing the. Further, if only one of the positive electrode and the negative electrode is accommodated in the bag-shaped ceramic separator, a predetermined number of the bag-shaped ceramic separator in which one is accommodated and the other electrode alternately. By laminating, the electrode assembly can be assembled. That is, in any case, since the electrode assembly can be assembled by performing the stacking operation for the total number of the positive electrode and the negative electrode, the positive electrode, the negative electrode, and the sheet shape Compared to the case where the separators are alternately stacked, the number of manufacturing steps of the electrode assembly can be reduced.

  Further, in a state where the electrode assembly is housed in the case of the power storage device (secondary battery) and incorporated in the power storage device, the separator does not necessarily need to maintain a bag shape. In the manufacturing process of the power storage device (secondary battery), there is a process of impregnating the active material applied to the positive electrode and the negative electrode constituting the electrode assembly housed in the case with an electrolyte solution. When it is welded or bonded with an adhesive, it is disadvantageous for the impregnation of the electrolytic solution. However, according to the present invention, since the ceramic separator is bonded in a bag shape between the opposing surfaces of the ceramic separator by a substance constituting the electrolyte, the electrolyte is contained in the case while the electrode assembly is accommodated in the case. When the material is injected (supplied), the substance dissolves in the electrolytic solution, so that there is no disadvantage for the impregnation of the electrolytic solution.

Also, for solid at normal temperature in the ethylene carbonate has a melting point of 39 ° C., the electrode sheet of the electrode sheet or the negative electrode for the positive electrode, it is easy to store in a state of being accommodated in a bag-like ceramic separator, moreover, the ceramic separator When joining, it melts easily and fulfills the function of a bonding agent.

According to a second aspect of the present invention, in the first aspect of the invention, the electrode assembly is configured in a state where at least the positive electrode is accommodated in the bag-shaped ceramic separator. The area for the positive electrode and that for the negative electrode are not the same, and the area for the positive electrode is smaller. Therefore, when the positive electrode is accommodated in the bag-shaped ceramic separator, the size of the ceramic separator is the same as that of the negative electrode, compared with the case where the negative electrode is accommodated in the bag-shaped ceramic separator. This makes it easy to secure a location for applying the material for use.

According to a third aspect of the invention, a lithium ion secondary battery having the configuration of a nonaqueous electricity storage device according to claim 1 or claim 2. Therefore, the lithium ion secondary battery of the present invention has the same effect as that of the first or second aspect of the invention.

  ADVANTAGE OF THE INVENTION According to this invention, the nonaqueous electrical storage apparatus and lithium ion secondary battery which can reduce the man-hour at the time of manufacturing the electrode assembly using the ceramic coat separator and ceramic separator which cannot be heat-welded can be provided. .

(A) is a partially broken perspective view of a secondary battery, (b) is a perspective view of a state in which a positive electrode is accommodated in a bag-shaped ceramic separator. The perspective view which shows the state which accommodates a positive electrode in a bag-shaped ceramic separator. The perspective view which shows the structure of an electrode assembly. (A), (b), (c) is a schematic perspective view which shows the procedure in which a positive electrode is accommodated in the bag-shaped ceramic separator of another embodiment.

Hereinafter, an embodiment in which the present invention is embodied in a lithium ion secondary battery as a nonaqueous power storage device will be described with reference to FIGS.
As shown in FIG. 1, in a lithium ion secondary battery 10 as a non-aqueous power storage device, a stacked electrode assembly 12 is accommodated in a case 11 constituted by a case main body 11a and a lid 11b. In addition, although not illustrated in the case 11, the electrolyte solution is also accommodated. In the following description, the longitudinal direction of the case 11 shown by the arrow Y1 in FIG. 1A is the left-right direction, the height direction of the case 11 shown by the arrow Y2 is the vertical direction, and the short side of the case 11 shown by the arrow Y3 is shown in FIG. The direction is the front-rear direction.

  In the electrode assembly 12, a plurality of positive electrode sheet-like electrodes 13 and a plurality of negative electrode sheet-like electrodes 14 are alternately arranged with a ceramic separator 15 interposed between the electrode 13 and the electrode 14. It is configured by stacking.

  As shown in FIGS. 1B and 2, the electrodes 13 and 14 are formed in a rectangular shape with active material layers 13 a and 14 a having a metal foil 16 coated with an active material, and the active material is applied to the electrodes 13 and 14. Active material non-applied portions 13b and 14b that are not provided are provided above the active material layers 13a and 14a. Tabs 13c and 14c protrude from the active material non-applied portions 13b and 14b. The tab 13 c is formed on the upper left side of the electrode 13, and the tab 14 c is formed on the upper right side of the electrode 14. In this embodiment, the active material layers 13a and 14a are formed on both surfaces of the electrode 13 and the metal foil 16 constituting the electrode 14, respectively.

  As shown in FIG. 1A, the positive electrode conductive member 18 is welded to the stacked group 17p of the tab 13c of the electrode 13, and the negative electrode conductive member 19 is welded to the stacked group 17n of the tab 14c of the electrode 14. Connected with. The positive electrode conductive member 18 is formed integrally with the positive electrode terminal 20 of the lithium ion secondary battery 10 penetrating the lid 11b. The negative electrode conductive member 19 is formed integrally with the negative electrode terminal 21 of the lithium ion secondary battery 10 penetrating the lid 11b. The positive electrode terminal 20 and the negative electrode terminal 21 are electrically insulated from the case 11 (the case body 11a and the lid body 11b).

  In this embodiment, the ceramic separator 15 is formed in a bag shape with a so-called ceramic coat separator in which a porous ceramic layer is formed on both surfaces of a resin base material in the form of a porous sheet. The tab 13c is accommodated in the bag-shaped ceramic separator 15 so as to protrude from the upper portion of the bag.

  The ceramic separator 15 is not bonded in a bag shape with an adhesive, but is bonded in a bag shape with a substance having a melting point of 25 ° C. or more contained in the electrolytic solution. If the melting point of the substance is 25 ° C. or more, when the electrode 13 is accommodated in the bag-shaped ceramic separator 15, the substance is cooled to the melting point or less in the state where the electrode 13 is sandwiched between the ceramic separators 15 coated with the molten substance. Can be solidified. Further, the melting point of the substance is set to about 25 ° C. or more at room temperature so that the substance stored in a solid state can be easily melted at a temperature of about room temperature when used. In this embodiment, ethylene carbonate (EC) is used as the substance.

  As the electrolytic solution of the lithium ion secondary battery 10, for example, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) is used in the same manner as a general electrolytic solution. . The mixing ratio is, for example, EC: DEC: DMC = 1: 1: 1. EC has a melting point of 39 ° C., DEC has a melting point of −43 ° C., and DMC has a melting point of 2 to 4 ° C.

  As shown in FIG. 2, the bag-shaped ceramic separator 15 is coated with melted EC at predetermined intervals on three sides excluding one side (upper side) of the opposing surfaces of the two ceramic separators 15. Two ceramic separators 15 are joined together with the electrode 13 sandwiched therebetween.

  Next, of the manufacturing steps of the lithium ion secondary battery 10 configured as described above, a bag-shaped ceramic separator manufacturing step in which the electrode 13 constituting the electrode assembly 12 is accommodated in the bag-shaped ceramic separator 15; The process of laminating the electrode 14 and the ceramic separator 15 will be described.

  When forming the bag-shaped ceramic separator 15, first, as shown in FIG. 2, liquid EC22 obtained by heating and melting EC on three sides of one side of the two ceramic separators 15 is spaced at a predetermined interval. Apply. Before the liquid EC 22 is solidified, the liquid EC 22 is solidified by pressing the peripheral edges of the two ceramic separators 15 with one electrode 13 sandwiched between the two ceramic separators 15. The ceramic separators 15 are joined in a bag shape. Thus, in the bag-shaped ceramic separator manufacturing process, the bag-shaped ceramic separator 15 in which the electrode 13 is accommodated is manufactured. The electrode 13 is housed in a predetermined position in the bag-shaped ceramic separator 15. The manufactured bag-shaped ceramic separator 15 is stored at a temperature at which EC does not melt.

  In the laminating step, as shown in FIG. 3, a predetermined number of bag-shaped ceramic separators 15 in which the electrodes 13 manufactured in the bag-shaped ceramic separator manufacturing step are accommodated are alternately stacked. Then, the electrode assembly 12 is formed in a state where the tabs 13c and 14c of the electrode 13 and the electrode 14 overlap each other. Therefore, the number of man-hours is reduced as compared with the case where a predetermined number of the electrodes 13, 14 and sheet-like ceramic separators 15 are alternately laminated. Further, the electrode 13 and the electrode 14 are not the same size, and the electrode 13 is smaller than the electrode 14. Therefore, when the size of the ceramic separator 15 is the same as the case where the electrode 13 is accommodated in the bag-shaped ceramic separator 15 as compared with the case where the electrode 14 is accommodated in the bag-shaped ceramic separator 15, the adhesive margin, that is, for bonding It becomes easy to secure a portion where the material (EC) is applied.

  In the welding step for the conductive member after the lamination step, the positive electrode conductive member 18 is placed on the laminated group 17p of the overlapped tab 13c, and the negative electrode conductive member 19 is placed on the laminated group 17n of the overlapped tab 14c. Welded. The electrode assembly 12 to which the positive electrode conductive member 18 and the negative electrode conductive member 19 are welded is accommodated in the case 11, and after the case 11 is sealed with the lid 11b, the electrolyte is injected from an electrolyte injection port (not shown). After a predetermined amount of electrolyte is injected (supplied) into the case 11, the injection port is sealed.

  Since the amount of EC constituting the electrolyte component affects the performance of the lithium ion secondary battery 10, the amount of EC in the injected electrolyte is the EC used in the bag-shaped ceramic separator 15 containing the electrode 13. Assuming that the amount is dissolved in the electrolyte, the composition of the electrolyte is controlled. That is, the EC amount of the electrolytic solution is adjusted based on the EC weight used for the bag-shaped ceramic separator 15 constituting the electrode assembly 12. Even after the EC used for bonding the ceramic separator 15 is dissolved in the electrolytic solution, a part of the EC remains in the bonding portion, and the amount of EC in that portion is larger than that in other portions.

Next, the operation of the lithium ion secondary battery 10 configured as described above will be described.
At the time of manufacturing the lithium ion secondary battery 10, after the electrode assembly 12 is accommodated in the case 11, an electrolytic solution is applied to the active material layers 13 a and 14 a formed on the electrode 13 and the electrode 14 constituting the electrode assembly 12. There is a process of impregnation. In the configuration in which the bag-shaped ceramic separator 15 is bonded in a bag shape with an adhesive, the electrolytic solution cannot be impregnated from the peripheral side bonded with the adhesive, which is disadvantageous for the impregnation of the electrolytic solution. However, in this embodiment, the EC in which the ceramic separator 15 is joined in a bag shape is a substance constituting the electrolytic solution, and is easily dissolved in the electrolytic solution, which is disadvantageous for the impregnation of the electrolytic solution. There is no. The amount of EC used for bonding the ceramic separator 15 is determined in anticipation that the EC used for bonding dissolves in the electrolytic solution, and therefore the bonding EC does not have an adverse effect.

  Although the lithium ion secondary battery 10 is used alone, it is generally used as an assembled battery in which a plurality of lithium ion secondary batteries 10 are connected in series or in parallel. The lithium ion secondary battery 10 is used for various applications. For example, the lithium ion secondary battery 10 is mounted on a vehicle and used as a power source for a traveling motor or a power source for other electrical devices.

  Since the ceramic separator 15 is used as the separator, the ceramic separator 15 is prevented from shrinking even at a temperature at which the resin-only separator shrinks, compared to the case where the resin-only separator is used as the separator. Therefore, the short circuit between the electrodes hardly occurs and the insulation between the electrodes is maintained.

According to this embodiment, the following effects can be obtained.
(1) A lithium ion secondary battery 10 includes a stacked electrode assembly in which a positive electrode sheet 13 and a negative electrode sheet 14 are stacked with a ceramic separator 15 interposed therebetween. Reference numeral 12 denotes a non-aqueous power storage device housed in the case 11 together with the electrolytic solution. The electrolytic solution contains a substance having a melting point of 25 ° C. or more, and at least one of the electrode 13 and the electrode 14 is an electrode in a state of being accommodated in a bag-like ceramic separator 15 joined by the substance to form a bag. The assembly 12 is configured. Therefore, the number of manufacturing steps of the electrode assembly 12 is reduced as compared to the case where the sheet-like electrode 13 for the positive electrode, the sheet-like electrode 14 for the negative electrode, and the sheet-like separator are alternately laminated. Further, in the manufacturing process of the non-aqueous power storage device (lithium ion secondary battery 10), the active material applied to the electrodes 13 and 14 constituting the electrode assembly 12 housed in the case 11 is impregnated with an electrolytic solution. However, when the separator is thermally welded or bonded with an adhesive, it is disadvantageous for the impregnation of the electrolytic solution. However, since the ceramic separator 15 is joined in a bag shape by a substance constituting the electrolytic solution, when the electrolytic solution is injected into the case 11 with the electrode assembly 12 being accommodated in the case 11, the substance is Since it dissolves in the electrolytic solution, there is no disadvantage for impregnation of the electrolytic solution.

  (2) The positive electrode 13 is accommodated in a bag-shaped ceramic separator 15. Therefore, when the size of the ceramic separator 15 is the same as that when the negative electrode 14 is accommodated in the bag-shaped ceramic separator 15, an area for applying a paste margin, that is, a bonding material (EC) is secured. It becomes easy.

  (3) The substance is ethylene carbonate (EC). Ethylene carbonate is used as an electrolyte for lithium ion secondary batteries and is easily available. In addition, since ethylene carbonate has a melting point of 39 ° C. and is solid at room temperature, it can be easily stored in a state where the electrode 13 is accommodated in the bag-shaped ceramic separator 15, and is easily melted when the ceramic separator 15 is joined. And serve as a bonding agent.

  (4) In the bag-shaped ceramic separator 15 in which the electrode 13 is accommodated, EC in a molten state is applied at predetermined intervals to the three sides of the opposing surfaces of the two ceramic separators 15, and the electrode is interposed between them. It is comprised by joining 13 on both sides. Therefore, the bag-shaped ceramic separator 15 in which the electrode 13 is accommodated can be easily manufactured.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The electrode assembly 12 is formed of a bag-shaped ceramic separator 15 in which not only the positive electrode 13 but also the negative electrode 14 are contained in an electrolyte solution and bonded with a substance having a melting point of 25 ° C. or more. It is good also as the accommodated structure.

  The electrode assembly 12 may be configured by alternately laminating the bag-shaped ceramic separator 15 in which the electrode 14 is accommodated and the electrode 13 not accommodated in the bag-shaped ceramic separator 15. That is, it is sufficient if at least one of the electrode 13 and the electrode 14 constituting the electrode assembly 12 is accommodated in the bag-shaped ceramic separator 15.

  The configuration of the bag-shaped ceramic separator 15 is not limited to the configuration in which two ceramic separators 15 are joined by EC. For example, a single ceramic separator 15 that is twice the size of the bag-shaped ceramic separator 15 to be formed is used. As shown in FIG. Apply with. Next, as shown in FIG. 4 (b), the ceramic separator 15 is folded in two, the electrode 13 is placed on the separator between the opposing surfaces, then folded in half, and the opposing surface folded in half is Joining with liquid EC22, liquid EC22 is solidified. As a result, as shown in FIG. 4C, a bag-shaped ceramic separator 15 in which the electrode 13 is accommodated is obtained.

  ○ The electrolyte solution may be a mixture of a substance that is liquid at room temperature and a substance having a melting point of 25 ° C. or higher, and is a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC). Not exclusively. For example, a mixture of EC and DEC or a mixture of EC and DMC may be used. Further, polypropylene carbonate (PC) may be mixed with a mixture of EC, DEC, and DMC, a mixture of EC and DEC, or a mixture of EC and DMC. As the electrolytic solution, a combination of a high-viscosity (high dielectric constant) solvent and a low-viscosity solvent is preferable because dissociation of the electrolyte salt and ion mobility are improved. EC and PC are high viscosity (high dielectric constant) solvents, and DMC and DEC are low viscosity solvents. Ethyl methyl carbonate (EMC) may be used as the low viscosity solvent.

  ○ The electrolyte solution does not contain ethylene carbonate (EC), is a non-aqueous electrolyte solution that can be used as an electrolyte solution for lithium ion secondary batteries, and contains a substance having a melting point of 25 ° C. or higher as a component. Also good.

  The positions of the tabs 13c and 14c formed on the electrode 13 and the electrode 14 are not limited to the upper left end or the upper right end of the electrode 13 or the electrode 14, but are closer to the center than the left end or the right end at the upper portion of the electrode 13 or the electrode 14. May be.

  The ceramic separator 15 is not limited to a ceramic coat separator in which ceramic layers are formed on both surfaces of a resin base material (resin layer), and may be a separator made entirely of ceramic. Moreover, the ceramic separator by which only one side was ceramic-coated may be sufficient.

(Circle) the electrode assembly 12 is good also as a structure accommodated in the case 11 in the state covered with the insulating bag which consists of an electrically insulating material.
The electrode 13 and the electrode 14 may have a structure in which active material layers 13a and 14a formed by applying an active material to one surface of the metal foil 16 are present. That is, the electrode 13 and the electrode 14 need only have active material layers 13 a and 14 a formed by applying an active material to at least one surface of the metal foil 16.

The non-aqueous power storage device is not limited to the lithium ion secondary battery 10 and may be a capacitor such as a lithium ion capacitor.
The following technical idea (invention) can be understood from the embodiment.

(1) A laminated electrode assembly in which a positive electrode sheet electrode and a negative electrode sheet electrode are laminated with a ceramic separator interposed therebetween is housed in a case together with an electrolyte. A method for manufacturing a water-based power storage device, comprising:
At least one of the positive electrode sheet-like electrode and the negative electrode sheet-like electrode is contained in a bag-shaped ceramic separator bonded with a substance having a melting point of 25 ° C. or more as a component of the electrolytic solution. After forming an electrode assembly and housing the electrode assembly in a case of a power storage device, the substance used for the bonding is dissolved in the electrolyte injected into the case to partially remove the components of the electrolyte A method for manufacturing a non-aqueous power storage device.

  DESCRIPTION OF SYMBOLS 10 ... Lithium ion secondary battery as an electrical storage apparatus, 11 ... Case, 12 ... Electrode assembly, 13 ... Sheet-like electrode for positive electrodes, 14 ... Sheet-like electrode for negative electrodes, 15 ... Ceramic separator.

Claims (3)

A non-aqueous power storage device in which a laminated electrode assembly in which a positive electrode sheet-like electrode and a negative electrode sheet-like electrode are laminated with a ceramic separator interposed therebetween is housed in a case together with an electrolytic solution Because
The electrolyte contains a substance having a melting point of 25 ° C. or higher,
At least one of the positive electrode and the negative electrode is accommodated in a bag-shaped ceramic separator in which the opposing surfaces of the ceramic separator are bonded to each other by the substance, and the electrode assembly is accommodated. constitute a solid, the agent nonaqueous electricity storage device comprising ethylene carbonate der Rukoto. At least the nonaqueous electricity storage device according to claim 1 in which the electrodes for the positive electrode constitutes the electrode assembly in a state of being accommodated in the bag-like ceramic separator. A lithium ion secondary battery provided with the structure of the non-aqueous electrical storage apparatus of Claim 1 or Claim 2 .