JP2014107210A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery having a high capacity usable as a stationary storage battery.SOLUTION: In a secondary battery having a cathode 11P, an anode 11N, a separator 13, and an electrolyte 14, the cathode 11P and/or the anode 11N are formed as comprising a plurality of electrode plates disposed so as to overlap each other via a gap through which the electrolyte 14 circulates, with current collectors 12P, 12N of the plurality of electrode plates being electrically connected together by collector connection parts 16P, 16N, whereby a secondary battery having a high capacity usable as a stationary storage battery is obtained.

Description

  The present invention relates to a secondary battery used for a stationary storage battery or the like.

  In recent years, secondary batteries have also been used as stationary storage batteries for storing electricity generated by solar power generation or wind power generation. When a secondary battery is used as a stationary storage battery, one of the required performances is an increase in capacity.

  As a method of increasing the capacity of the secondary battery, it is conceivable that the electrode is first thickened. However, if the electrode is thickened, the active material located inside the electrode away from the surface of the electrode does not contribute to charge / discharge. It becomes difficult to utilize all of the active material contained in the. Therefore, even if the electrode is made thicker, a capacity proportional to the thickness of the electrode cannot be obtained, so that the capacity is improved by various methods.

  For example, in Patent Document 1, a capacity is improved by forming a groove in an electrode of a deposited film or a sintered film and securing a flow path of an electrolytic solution.

JP 2006-120445 A

  However, in the method of Patent Document 1, it is difficult to form an electrode having a thickness of, for example, 200 μm or more. Even if a groove can be formed in the thickness direction, the active material around the groove contributes to charging and discharging. Since the active material away from the groove does not contribute to charging / discharging, there is a problem that the capacity cannot be increased.

  The present invention has been made in view of the above problems, and an object thereof is to provide a secondary battery having a high capacity that can be used as a stationary storage battery.

  The secondary battery of the present invention includes a positive electrode, a negative electrode, a separator, and an electrolyte solution, and at least one of the positive electrode and the negative electrode includes a plurality of electrode plates each having a current collector, and the current collector And a plurality of electrode plates arranged so as to overlap each other via a gap, and having the electrolyte solution in the gap. And

  According to the present invention, it is possible to provide a secondary battery having a high capacity that can be used as a stationary storage battery by allowing an electrolytic solution to flow through a gap between a plurality of electrode plates arranged to overlap each other. it can.

It is sectional drawing which shows the 1st example of embodiment of the secondary battery of this invention. It is sectional drawing which shows the 2nd example of embodiment of the secondary battery of this invention. It is sectional drawing which shows the 3rd example of embodiment of the secondary battery of this invention. It is sectional drawing which shows the 4th example of embodiment of the secondary battery of this invention. It is sectional drawing which shows the conventional secondary battery.

  Hereinafter, the secondary battery of the present invention will be described in detail with reference to the drawings. As shown in FIG. 5, the secondary battery generally includes a positive electrode 1 </ b> P, a negative electrode 1 </ b> N, a separator 3, an electrolyte solution 4, and a case 5 that houses them. The positive electrode 1P and the negative electrode 1N are formed on the surfaces of the positive electrode side current collector 2P and the negative electrode side current collector 2N, which are metal foils, for example, as application electrodes containing a positive electrode active material and a negative electrode active material, respectively, and lead 7P , 7N and are electrically connected to the positive external terminal 8P and the negative external terminal 8N. The separator 3 is disposed between the positive electrode 1P and the negative electrode 1N. The case 5 accommodates the positive electrode 1P, the negative electrode 1N, and the separator 3 and is filled with the electrolytic solution 4, and is provided with a lid (not shown) in order to maintain airtightness.

(First example of embodiment)
A first example of the embodiment of the secondary battery of the present invention will be described. In the present embodiment, as shown in FIG. 1, the positive electrode 11P is composed of three electrode plates 11Pa, 11Pb and 11Pc, and the negative electrode 11N is similarly composed of three electrode plates 11Na, 11Nb and 11Nc. The separator 13 and the electrolytic solution 14 are housed in a case 15.

  The electrode plates 11Pa, 11Pb, and 11Pc are formed on the surfaces of the positive electrode current collectors 12Pa, 12Pb, and 12Pc, respectively, as application electrodes that include a positive electrode active material. The electrode plates 11Pa of the positive electrode current collectors 12Pa, 12Pb, and 12Pc , 11Pb and 11Pc are joined to each other to constitute a positive electrode side current collector joint 16P. Furthermore, the positive electrode side current collector bonding portion 16P is electrically connected to the positive electrode side external terminal 18P through a lead 17P.

  The electrode plates 11Na, 11Nb, and 11Nc are formed on the surfaces of the negative electrode current collectors 12Na, 12Nb, and 12Nc, respectively, as coated electrodes that include a negative electrode active material. The negative electrode side current collectors 12Na, 12Nb, and 12Nc The portions where the plates 11Na, 11Nb, and 11Nc are not formed are joined together to form a negative electrode side current collector joint 16N. Further, the negative electrode side current collector joint portion 6N is electrically connected to the negative electrode side external terminal 18N via a lead 7N.

  The electrode plates 11Pa, 11Pb and 11Pc constituting the positive electrode 11P, and the electrode plates 11Na, 11Nb and 11Nc constituting the negative electrode 11N (may be simply referred to as electrode plates as well. Similarly, the current collectors 12Pa to 12Pc and the current collectors) 12Na to 12Nc may be simply referred to as current collectors) so as to overlap each other with a gap between them, even if the thickness of the positive electrode 11P and the negative electrode 11N is increased overall, the positive electrode 11P and the negative electrode Since the electrolyte solution can be circulated through the gaps between the electrode plates constituting 11N, the contact area between the active material contained in the electrode plate and the electrolyte solution is increased, and the contribution ratio to charge / discharge of the active material is improved. Capacity can be improved. It should be noted that the size of the gap (distance between the electrode plates) interposed between the electrode plates is not particularly limited as long as the electrolyte solution can be circulated.

  For example, in the case of a coated electrode, the electrode plate may be produced as follows. For example, 80% by mass of an active material, 10% by mass of acetylene black as a conductive assistant, 10% by mass of polyvinylidene fluoride as a binder, and 15% by mass of NMP (N-methylpyrrolidone) as a solvent are added. To make a slurry. An electrode containing an active material, a conductive additive, and a binder by applying the prepared slurry to a metal foil serving as a current collector by a known sheet forming method such as a doctor blade method and drying the solvent. A plate can be produced. In addition, you may repeat the process of apply | coating and drying a slurry on metal foil in multiple times.

  As the material of the current collector, a material having corrosion resistance that does not cause a reaction such as dissolution at the potential of the positive electrode may be used on the positive electrode side. Examples of such materials include metal materials and alloys including nickel, aluminum, tantalum, niobium, titanium, gold, platinum, etc., carbonaceous materials such as graphite, hard carbon, glassy carbon, ITO glass, tin oxide, etc. Inorganic conductive oxide materials can be used. Among these, nickel, aluminum, titanium, gold, and platinum are preferable because they have excellent corrosion resistance and can be easily obtained. Aluminum is particularly preferable because it is passivated by forming an oxide film on the surface and excellent in corrosion resistance even at a high potential.

  For the negative electrode side, a material that does not cause side reactions such as alloying with an alkali metal such as Li or Na at the potential of the negative electrode may be used. Examples of such materials include metal materials and alloys including copper, nickel, brass, zinc, aluminum, stainless steel, tungsten, gold, platinum, carbonaceous materials such as graphite, hard carbon, and glassy carbon, ITO glass. An inorganic conductive oxide material such as tin oxide can be used. In particular, it is preferable to use aluminum or nickel from the viewpoint of high conductivity and relatively low cost. Aluminum, in particular, has high conductivity and is relatively inexpensive like copper and nickel, and cannot be used because it forms an alloy with Li, but is inactive with Na. Also, it can be used as a current collector.

  A foil, mesh, or expanded metal made of these metal materials may be used as a current collector, or a conductive material using a metal material, a carbonaceous material, or an inorganic conductive oxide material such as ITO glass or tin oxide as a filler. Alternatively, a conductive ink or the like applied to the electrode surface and dried may be used. Moreover, although metal, such as platinum, aluminum, and titanium, may be vapor-deposited on the electrode surface, in the present embodiment, a metal foil (for example, punching metal) having a through hole or a mesh shape is used as a current collector. It is preferable to use these metals.

  Usually, an electrode plate made of a coating film or the like contains an electrolyte solution of 40 to 50% of its volume, and ions responsible for electrical conduction (hereinafter sometimes simply referred to as ions) pass through the inside of the electrode plate. However, if the current collector on which the electrode plate is applied is a metal foil, ions that conduct electricity cannot pass through the current collector, and the ion flow path is the current collector. It becomes only the outer periphery. On the other hand, when a metal foil having a through-hole or a mesh-like metal is used as the current collector, the electrolyte solution can be circulated through the electrode plate through the through-hole or mesh opening of the current collector. And the contact area between the electrolyte solution and the capacity can be further improved.

  Further, the size or mesh roughness of the through holes of 12Pc and 12Nc, which are current collectors of the electrode plates 11Pc and 11Nc arranged in the vicinity of the separator 13, is set to be equal to that of the electrode plates 11Pa and 11Na arranged on the side far from the separator 13. It is preferable to make it larger than the size or the mesh roughness of the through holes of 12Pa and 12Na that are current collectors.

  Ions responsible for electrical conduction move between the positive electrode side and the negative electrode side via the separator 13 during charging / discharging of the secondary battery, but the ion concentration is high in the vicinity of the separator 13, and the ion concentration decreases as the distance from the separator 13 increases. Therefore, the charge / discharge efficiency of the electrode plate decreases as the distance between the electrode plate and the separator 13 increases.

  The one away from the separator 13 with a low ion concentration from the vicinity of the separator 13 with a high ion concentration by increasing the size of the through-hole or the mesh roughness of the current collector of the electrode plates 11Pc and 11Nc located in the vicinity of the separator 13 The ions can easily move to the electrode plate, the utilization rate of the active materials of the electrode plates 11Pa and 11Na separated from the separator 13 can be improved, and the capacity is improved.

  Thus, the effect of facilitating the movement of ions in the vicinity of the separator 13 away from the separator 13 is that the porosity of the electrode plates 11Pc and 11Nc arranged in the vicinity of the separator 13 It can also be obtained by making it larger than the porosity of the electrode plates 11Pa and 11Na arranged on the surface.

  In addition, when using metal foil or a mesh-shaped metal as a collector, it is preferable that the thickness shall be 10-300 micrometers. Moreover, when using metal foil, you may use what roughened the surface of metal foil in order to improve the adhesive force with an electrode.

  Further, the current collectors 12Pa to 12Pc and 12Na to 12Nc may be embedded in the electrode plates 11Pa to 11Pc and 11Na to 11Nc, respectively.

  Examples of the active material used for the positive electrode 11P include lithium cobalt composite oxide, lithium manganese composite oxide, manganese dioxide, lithium nickel composite oxide, lithium nickel cobalt composite oxide, lithium vanadium composite oxide, and vanadium oxide. Examples thereof include sodium cobalt composite oxide, sodium manganese composite oxide, manganese dioxide, sodium nickel composite oxide, sodium nickel iron composite oxide, sodium iron composite oxide, and sodium chromium composite oxide.

The active material used for the negative electrode 11N differs depending on whether an aqueous or non-aqueous electrolyte solution 14 is used. When using an aqueous electrolyte, activated carbon or NaTi ₂ (PO ₄ ) ₃ can be used. When using a non-aqueous electrolyte, in addition to an active material that can be used with an aqueous electrolyte, Glass materials such as SN-Sb composite glass, carbon materials such as graphite, hard carbon, and soft carbon, metal Li, metal Na, and alloys capable of inserting and removing Li and Na, titanium oxide, niobium oxide, lithium titanium composite An oxide material such as an oxide or a sodium titanium composite oxide can be used.

  Conductive aids include ketjen black, carbon nanotubes, carbon materials such as graphite and hard carbon instead of acetylene black, powders of metals (aluminum, gold, platinum, etc.), inorganic conductive oxides (indium tin oxide (ITO)) Any material may be used as long as it is chemically stable and conductive in the operating voltage range, such as glass and tin oxide.

  In addition to polyvinylidene fluoride, for example, polytetrafluoroethylene (PTFE), carboxymethylcellulose (CMC), styrene butadiene rubber (SBR), polyacrylic acid (PAA) polyimide resin (PI), polyamide resin, polyamide It is possible to select and use an imide resin, a fluorine rubber, or the like that does not decompose in the potential region to be used and is suitable for the application.

  What is necessary is just to adjust suitably the structure ratio of an active material, a conductive support material, and a binder in the range of 50 to 95%, 3 to 40%, and 2 to 10% by weight ratio, respectively.

  In addition, when the electrode plate is produced by itself, such as a sheet formed on a base film or a green compact, it is necessary to electrically connect the produced electrode plate to a current collector. is there. As a method of joining the electrode plate and the current collector, a method of pressure bonding the electrode plate and the current collector, a method of joining using a conductive adhesive, a method such as vapor deposition, CVD, or plating on the surface of the electrode plate An appropriate method may be selected from known methods such as a method of forming a current collector. Alternatively, a single electrode plate may be superimposed on the coated electrode formed on the metal foil, and bonded by a method such as pressure bonding.

The average particle diameter of the active material particles in the electrode plate is selected from a range of 0.1 to 50 μm, for example, in accordance with the use conditions such as the voltage range and temperature of the secondary battery using the active battery. Adjust it.

  The average particle size of the active material particles in the electrode plate can be controlled by adjusting the particle size of the active material powder when the electrode plate is formed by a coated electrode or a green compact. The average particle diameter of the active material particles in the electrode plate is, for example, a photograph taken by distinguishing the active material particles by a scanning electron microscope (SEM) and wavelength dispersive X-ray analysis (WDS) in the cross section of the electrode plate Can be obtained by image analysis.

  The electrolytic solution 14 can be either an aqueous electrolytic solution or a non-aqueous electrolytic solution. In particular, the aqueous electrolyte has a high ionic conductivity and is desirable as the electrolyte 14 of the secondary battery having the electrode structure of the present invention.

As the aqueous electrolyte, for example, an aqueous solution of 0.1 to 10.0 mol / L lithium sulfate, lithium nitrate, lithium hydroxide, lithium chloride, sodium sulfate, sodium nitrate, sodium hydroxide, sodium chloride, or the like can be used. .

The non-aqueous electrolyte is composed of an organic solvent and an electrolyte salt, and an additive for the purpose of forming a film on the electrode surface, preventing overcharge, imparting flame retardancy, or the like may be added as necessary. As the organic solvent, those having a high dielectric constant, low viscosity and low vapor pressure are preferably used. Examples of such materials include ethylene carbonate (EC), propylene carbonate, butylene carbonate, and γ-butyrolactone. , Sulfolane, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, or a mixture of two or more thereof. It is done. As the electrolyte salt, for example LiBF4, LiPF6, LiClO4, LiCF3SO3, LiAsF6, LiN (CF3SO2) 2, or lithium salts such as LiN (C2F5SO2), sodium perchlorate (NaClO _4), tetrafluoride sodium borate (NaBF ₄ ), Sodium hexafluorophosphate (NaPF ₆ ), NaN (FSO ₂ ) ₂ , NaN (CF ₃ SO ₂ ) ₂ , NaN (C ₂ F ₅ SO ₂ ) _{2 and the} like, and sodium salts such as 0.1 It can be used at a concentration of ˜10.0 mol / L. Of these electrolyte salts, NaN (SO ₂ F) ₂ , NaN (CF ₃ SO ₂ ) _2, and NaN (C ₂ F ₅ SO ₂ ) ₂ are mixed with other alkali metal salts to a certain temperature or higher. It can be used as a molten salt.

  The separator 13 impregnated with the aqueous electrolyte solution or the non-aqueous electrolyte solution is required to pass ions and prevent a short circuit between the positive and negative electrodes. Specifically, a polyolefin fibrous nonwoven fabric, a polyolefin microporous film, a glass filter, a ceramic porous material, or the like can be used. Here, examples of the polyolefin include polyethylene and polypropylene, and a separator generally used for a secondary battery such as a lithium ion battery is applicable.

  In the present embodiment, FIG. 1 shows an example in which each of the positive electrode 11P and the negative electrode 11N is composed of three electrode plates. However, as for the number of electrode plates, one of the positive electrode 11P and the negative electrode 11N is plural. As long as it has the electrode plate, there is no particular limitation. In other words, as long as one of the positive electrode 11P and the negative electrode 11N has a plurality of electrode plates, the other may be a single electrode plate.

(Second example of embodiment)
As in the first example of the above-described embodiment, the second example of the embodiment of the secondary battery according to the present invention includes a positive electrode 21P having three electrode plates 21Pa, 21Pb, and 21Pc as shown in FIG. The negative electrode 21N is composed of three electrode plates 21Na, 21Nb, and 21Nc, which are housed in a case 25 together with the separator 23 and the electrolytic solution 24.

  The other structures of the current collectors 22Pa to 22Pc, 22Na to 22Nc, the current collector junctions 26P and 26N, and the connection structure with the external terminals 28P and 28N are the same as those in the above-described embodiment, and thus the description thereof is omitted. .

  In the present embodiment, the length of each electrode plate in the vertical direction in FIG. 2 is sequentially increased from the electrode plates 22Pa and 22Na located on the side far from the separator 23 to the electrode plates 22Pc and 22Nc located in the vicinity of the separator 23. By setting the length to be shorter, the area of the main surface of the electrode plate located near the separator 23 is smaller than the area of the main surface of the electrode plate located farther from the separator 23. In this way, by reducing the area of the electrode plate located in the vicinity of the separator 23 having a high ion concentration, ions can be easily moved away from the separator 23 having a low ion concentration. The utilization rate of the active material of the board is further improved, and the capacity is further improved. In addition, the area of the electrode plate located on the side away from the separator 23 having a low ion concentration is increased, and the contact area between the electrode plate and the electrolyte solution 24 is increased. Utilization rate is further improved.

(Third example of embodiment)
As in the first and second examples of the above-described embodiment, the third example of the embodiment of the secondary battery according to the present invention includes three electrode plates 31Pa and 31Pb as shown in FIG. The negative electrode 31N is composed of three electrode plates 31Na, 31Nb, and 31Nc, and these are housed in a case 35 together with the separator 33 and the electrolyte solution 34.

  The other structures of the current collectors 32Pa to 32Pc, 32Na to 32Nc, current collector junctions 36P and 36N, and the connection structure with the external terminals 38P and 38N are also the same as those in the above-described embodiment, and thus the description thereof is omitted. .

  In the present embodiment, the electrode plates 31Pc, 31Pb, 31Nc and 31Nb positioned in the vicinity of the separator 33 are further divided into a plurality of small electrode plates (31Pb ′, 31Nb ′, etc.) on the same plane with the gaps 39Pc, 39Pb, It is assumed that they are arranged to have 39Nc and 39Nb. In this way, by dividing one electrode plate into a plurality of small electrode plates and providing a gap between the small electrode plates, ions move between one main surface and the other main surface of the electrode plate. Since such an electrode plate is located closer to the separator 33, the movement of ions further away from the separator 33 is facilitated, and the active material of the electrode plate located farther from the separator 33 can be reduced. The utilization rate is improved and the capacity is improved.

  Further, when the electrode plates adjacent to each other, such as the electrode plates 31Pb and 31Pc and the electrode plates 31Nb and 31Nc, are composed of a plurality of small electrode plates, for example, the gap 39Pb between the small electrode plates of the electrode plate 31Pb And the gap 39Pc between the 31Pc small electrode plates are preferably arranged at positions that do not face each other. By shifting the position of the gap in this way, there is an effect that the movement of ions to the electrode plate located farther from the separator becomes easier.

(Fourth example of embodiment)
In the fourth example of the embodiment of the secondary battery of the present invention, as shown in FIG. 4, the positive electrode 41P is composed of five electrode plates 41Pa, 41Pb, 41Pc, 41Pd and 41Pe, and the negative electrode 41N is composed of five The electrode plates 41Na, 41Nb, 41Nc, 41Nd, and 41Ne are housed in a case 45 together with the separator 43 and the electrolytic solution 44.

Other configurations of current collectors 42Pa to 42Pe, 42Na to 42Ne, current collector junction 46P
The connection structure etc. with 46N and external terminals 48P and 48N are also the same as those in the above-described embodiment, and the description thereof will be omitted.

  In the present embodiment, the angle θ formed between the main surface of the electrode plates 41Pa to 41Pe on the positive electrode 41P side and the central surface 43C of the separator 43 (the central surface equidistant from the positive electrode 41P and the negative electrode 41N) is 45 °. It has become. Similarly, the main surfaces of the electrode plates 41Na to 41Ne on the negative electrode 41N side form an angle of 45 ° with the central surface 43C of the separator 43, and 90 ° to the main surfaces of the electrode plates 41Pa to 41Pe on the positive electrode 41P side. It makes an angle. Thus, by arranging the plurality of electrode plates so that the angle θ formed by the main surface of the electrode plate and the center surface 43C of the separator 43 is 5 to 90 °, the vicinity of the separator 43 and the side far from the separator 43 The ions move more easily, the utilization of the active material of the electrode plate located far from the separator 43 is improved, and the capacity is improved.

  The angle θ formed between the main surface of the electrode plate and the central surface of the separator may be confirmed by directly measuring the angle, or the distance between the main surface of the electrode plate and the central surface of the separator is measured at least two points. Then, the difference may be calculated from the length between two points on the separator or the electrode plate.

Hereinafter, the secondary battery of this invention is demonstrated in detail based on an Example. The positive electrode is 80% by mass of sodium manganate (Na _0.66 MnO ₂ ) powder as a positive electrode active material, 10% by mass of acetylene black as a conductive additive, 10% by mass of polyvinylidene fluoride as a binder, and NMP ( N-methylpyrrolidone) is mixed to prepare a slurry, applied onto a Ni mesh (# 80, thickness 200 μm) serving as a positive electrode current collector by a doctor blade method, the solvent is dried, A separately prepared green compact was stacked thereon and pressure-bonded, and cut into a required shape to prepare an electrode plate. The thickness of the electrode plate was adjusted according to the coating conditions, the thickness of the green compact, and the number of sheets to be stacked.

  Five types of positive electrodes (A to E) having different structures were produced using the produced electrode plates.

  The structure A was a single plate electrode having a length of 50 mm and a width of 25 mm. The content of the positive electrode active material amount of the electrode was adjusted by changing the thickness of the electrode plate.

  The structure B corresponds to the first example of the embodiment, and includes a plurality of electrode plates having a length of 50 mm, a width of 25 mm, and a thickness of 0.5 mm. The content of the positive electrode active material amount of the electrode was adjusted by the number of electrode plates.

  The structure C corresponds to the second example of the embodiment, and is configured by three types of electrode plates having a thickness of 0.5 mm, the same width and different lengths, and the shorter the length of the electrode plate, the more It arrange | positions so that it may become the separator vicinity.

  Structure D corresponds to the third example of the embodiment, and is composed of a single plate electrode plate and an electrode plate composed of a plurality of small electrode plates, and the single plate electrode plate is disposed on the side farthest from the separator. It is. A single electrode plate and an electrode plate composed of a plurality of small electrode plates are both 50 mm long and 0.5 mm thick. The small electrode plate is 5 mm long and 0.5 mm thick and has a width of the electrode plate. It is equal to the width, and the gap between adjacent small electrode plates is 5 mm in the length direction. The small electrode plate located on the outer edge of the small electrode plate (corresponding to the small electrode plate located at the top and bottom of the electrode plate composed of the small electrode plates shown in FIG. 3) has a length of 2.5 mm.

The structure E corresponds to the fourth example of the embodiment, and includes a plurality of electrode plates each having a length of 25 mm, a width of 50 mm, and a thickness of 0.5 mm each containing 1 g of a positive electrode active material. The angle formed with the center plane is 45 °.

  Details of each electrode structure are shown in Table 1. In any structure, the length is the length in the vertical direction of the corresponding cross-sectional view, the width is the length in the direction perpendicular to the plane of the corresponding cross-sectional view, and between the electrode plates when using a plurality of electrode plates The gap was 0.5 mm.

  The negative electrode is a mixture of 80% by mass of activated carbon powder as a negative electrode active material, 10% by mass of acetylene black as a conductive additive, 10% by mass of polyvinylidene fluoride as a binder, and 15% by mass of NMP (N-methylpyrrolidone) as a solvent. Thus, a slurry was prepared. This slurry is applied by a doctor blade method onto a Ni mesh (roughness # 80, thickness 200 μm) serving as a negative electrode side current collecting layer, the solvent is dried, and a green compact prepared separately is stacked thereon. By bonding and pressing, a negative electrode plate having a thickness only twice that of the positive electrode plate having the above-described shape was produced.

  Using the produced positive electrode and the corresponding negative electrode, a battery evaluation cell having a structure as shown in Table 2 was produced, and the battery characteristics were evaluated.

  Glass filter paper was used as the separator. As the aqueous electrolyte, an aqueous sodium sulfate solution having a concentration of 1 mol / L was used. As the organic electrolyte, a solution obtained by dissolving 1 mol / L of NATSFI in a mixed solvent in which the ratio of ethylene carbonate (EC) and diethyl carbonate (DEC) was EC: DEC = 3: 7 as a volume ratio was used. .

The charge / discharge characteristics of the fabricated cell were confirmed under the following conditions, and the discharge capacity was measured. The measurement results of the discharge capacity are shown in Table 2. Charge / discharge voltage range: 1.6 V upper limit, 0.1 V lower limit (aqueous electrolyte)
Upper limit 3.8V, lower limit 0.1V (organic electrolyte)
Charge / discharge current value: 0.5 mA / cm ² (constant current charge / discharge)
Measurement temperature: 30 ° C

  From Table 2, the sample No. of the structure A composed of only a single plate electrode. Sample Nos. 1, 4, and 9 are arranged such that a plurality of electrode plates are arranged to overlap each other with a gap therebetween. In 2, 3, 5-8, and 10-13, it was confirmed that a high capacity was obtained even when the content of the positive electrode active material was the same.

1P, 11P, 21P, 31P, 41P: Positive electrodes 1N, 11N, 21N, 31N, 41N: Negative electrodes 31Pb ′, 31Nb ′: Small electrode plates 2P, 12P, 22P, 32P, 42P: Positive electrode side current collectors 2N, 12N, 22N, 32N, 42N: Negative electrode side current collector 3, 13, 23, 33, 43: Separator 43C: Separator center plane 4, 14, 24, 34, 44: Electrolyte solution 5, 15, 25, 35, 45: Cases 16P, 26P, 36P, 46P: Positive current collector junctions 16N, 26N, 36N, 46N: Negative current collector junctions 8P, 18P, 28P, 38P, 48P: Positive external terminals 8N, 18N, 28N , 38N, 48N: negative external terminals 39Pb, 39Pc, 39Nb, 39Nc: gaps between small electrode plates

Claims (9)

Having a positive electrode, a negative electrode, a separator and an electrolyte,
At least one of the positive electrode and the negative electrode is
Each of the plurality of electrode plates each having a current collector and a current collector connection portion that electrically connects the current collectors to each other, and the plurality of electrode plates are arranged to overlap each other with a gap therebetween. And
A secondary battery comprising the electrolytic solution in the gap.   The secondary battery according to claim 1, wherein the current collector is made of a metal foil having a through hole or a mesh-like metal.   The mesh roughness of the current collector provided in the electrode plate located in the vicinity of the separator is larger than the mesh roughness of the current collector provided in the electrode plate located on the side far from the separator. The secondary battery according to claim 2, characterized in that:   The porosity of the said electrode plate located in the vicinity of the said separator is larger than the porosity of the said electrode plate located in the side far from the said separator, The two of Claim 1 thru | or 3 characterized by the above-mentioned. Next battery.   The area of the main surface of the electrode plate located in the vicinity of the separator is smaller than the area of the main surface of the electrode plate located on the side far from the separator. Secondary battery. Among the plurality of electrode plates, at least an electrode plate positioned in the vicinity of the separator is a plurality of small electrode plates arranged on the same plane so as to have a gap between each other, and the gap between the small electrode plates is The secondary battery according to claim 1, comprising an electrolytic solution. Among the plurality of electrode plates, the electrode plates are adjacent to each other, and all of the plurality of small electrode plates are arranged so as to have a gap on the same plane, and the gaps between the small electrode plates do not face each other. The secondary battery according to claim 6, wherein the secondary battery is disposed at a position.   The plurality of electrode plates are arranged such that a main surface of the electrode plates and a central surface of the separator form an angle of 5 to 90 °. Secondary battery.   The secondary battery according to claim 1, wherein the electrolytic solution is an aqueous electrolytic solution.

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