JP6992692B2 - Lithium-sulfur battery and method for manufacturing lithium-sulfur battery - Google Patents

Description

The present invention relates to a lithium-sulfur battery and a method for manufacturing a lithium-sulfur battery.

Secondary batteries are widely used in digital home appliances, electric vehicles, hybrid vehicles, solar power generation equipment, and the like. A lithium secondary battery is mentioned as this secondary battery, and among the lithium secondary batteries, a lithium sulfur battery (for example, Patent Document 1 and the like) has been attracting attention in recent years. In a lithium-sulfur battery, a positive electrode material having a sulfur-containing active material and a current collector and a negative electrode material having a lithium-containing active material and a current collector are opposed to each other via a separator. It is configured by arranging multiple electrodes side by side and accommodating them in the exterior body. The lithium-sulfur battery may also be housed in a case. Lithium ions pass through the separator.

Japanese Unexamined Patent Publication No. 2013-114920

At the positive electrode of a lithium-sulfur battery, lithium polysulfide is generated during the multi-step reaction between sulfur and lithium, but lithium polysulfide (Li 2S _x , ₁ ≦ x ≦ 8) tends to elute into the electrolytic solution. The eluted lithium polysulfide diffuses as an anion. In Patent Document 1, the separator is made of a polymer non-woven fabric, a resin microporous film, or the like, but anions of lithium polysulfide permeate the separator and diffuse into the negative electrode. When the polysulfide ion reacts with lithium in the negative electrode, the charging reaction is not promoted (a so-called redox shuttle phenomenon occurs), and the charge / discharge capacity and charge / discharge efficiency decrease.

The present invention has been made in view of such circumstances, and is a method for manufacturing a lithium-sulfur battery and a lithium-sulfur battery in which a positive electrode and a negative electrode are well separated to suppress a decrease in charge / discharge capacity and charge / discharge efficiency. The purpose is to provide.

The lithium sulfur battery according to the present invention has a flat plate-shaped first collector, two first electrodes provided on each plane of the first collector and having the same polarity, and the first collector. The first electrode material having a bag-shaped cation exchange film accommodating the first electrode, the flat plate-shaped second current collector, and the first electrode facing the first electrode via the cation exchange film. 2 A second electrode material provided on the plane of the current collector and having a second electrode having a polarity different from that of the first electrode is provided, and one of the first electrode and the second electrode is active containing sulfur. The positive electrode has a substance, and the other is a negative electrode having an active material containing lithium.

The method for manufacturing a lithium sulfur battery according to the present invention is a method for manufacturing a lithium sulfur battery having a positive electrode having an active material containing sulfur and a negative electrode having an active material containing lithium, and is a flat plate-shaped first current collector. Two first electrodes having the same polarity are provided on each plane of the body, the first current collector provided with the first electrode is covered with a cation exchange film, and the end portion of the cation exchange film is covered with a cation exchange film. A first electrode material is produced by bonding, and a second electrode having a polarity different from that of the first electrode is provided on a flat surface of a flat plate-shaped second current collector to produce a second electrode material, and the first electrode is produced. The material and the second electrode material are arranged so that the first electrode and the second electrode face each other, and the first electrode material and the second electrode material are covered with an exterior body.

According to the present invention, since the first electrode of the first electrode material is covered with an ion exchange membrane, the positive electrode and the negative electrode can be well separated, and deterioration of charge / discharge capacity and charge / discharge efficiency can be suppressed. ..

It is a schematic plan view which shows the lithium-sulfur battery which concerns on Embodiment 1 of this invention. FIG. 2 is a schematic cross-sectional view taken along the line II-II of FIG. It is a schematic plan view of an electrode material. FIG. 3 is a sectional view taken along line IV-IV of FIG. It is a schematic cross-sectional view which shows the battery which concerns on Embodiment 2. FIG. It is a schematic sectional drawing which shows the battery which concerns on Embodiment 3. FIG. It is a schematic sectional drawing which shows the battery which concerns on Embodiment 4. FIG. It is a schematic cross-sectional view which shows the battery which concerns on Embodiment 5.

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments thereof.
Embodiment 1.
As shown in FIGS. 1 and 2, the lithium-sulfur battery 1 (hereinafter referred to as battery 1) according to the first embodiment includes an exterior body 2, positive electrode materials 5, and 5, and negative electrode materials 6, 7. , 7 and so on. The positive electrode terminal 3 and the negative electrode terminal 4 project from a part of the peripheral portion of the exterior body 2. The battery 1 alone or a combination of the battery 1 and another battery 1 may be housed in a case (not shown).

The electrode material 5 of the positive electrode has a current collector 51, an electrode 52, and a cation exchange membrane (hereinafter referred to as an ion exchange membrane) 53.
The current collector 51 has a rectangular plate shape, and square flat plate-shaped electrodes 52 are provided on both planes. The ion exchange membrane 53 covers the side surface and the flat surface of the electrode 52, and the exposed portion of the side surface and the flat surface of the current collector 51.

FIG. 3 is a schematic plan view of the electrode material 5, and FIG. 4 is a sectional view taken along line IV-IV of FIG.
As shown in FIGS. 2 to 4, the ion exchange membrane 53 has a bag shape, and the current collector 51 and the electrode 52 are housed inside the bag. The ion exchange membrane 53 has a bag shape by adhering the peripheral edges of two sheet-shaped ion exchange membranes. The ion exchange membrane 53 may be formed into a bag shape by bending a single rectangular ion exchange membrane at the central portion in the longitudinal direction and aligning the ends thereof.
The tab 51a protrudes from a part of the peripheral edge of the current collector 51. The tab 51a protrudes from a part of the peripheral edge of the ion exchange membrane 53 and is adhered to the ion exchange membrane 53 via the adhesive layer 54. The peripheral edge portion of the ion exchange membrane 53 other than the protruding portion of the tab 51a is bonded by heat welding. The current collector 51 and the tab 51a may be integrally formed or may be formed separately.

The electrode 52 has an active material containing sulfur or a sulfur compound, carbon, and a binder.
Examples of sulfur include crystalline sulfur, insoluble sulfur, and those compounded with carbon. The active material may contain lithium.
Examples of carbon include carbon black, graphitized carbon black, activated carbon, graphite, carbon nanotubes (CNT), carbon fiber (CNF) and the like.
As the binder, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), fluororesin (polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HEP), polytetrafluoroethylene (polytetrafluoroethylene) PTFE))), polyimide, polyamideimide, sodium alginate, polyvinylidene acid, polyethylene oxide and the like can be mentioned.
A porous polyolefin film or a glass separator may be provided on the electrode 52 as a liquid-retaining layer.
Examples of the current collector 51 include aluminum foil, carbon-coated aluminum foil, stainless steel foil, and the like, perforated foil having holes in them, aluminum mesh, and stainless steel mesh.
The electrodes 52 and 52 and the current collector 51 are housed in a bag-shaped ion exchange membrane 53.

The ion exchange membrane 53 is preferably a fluorine-based cation exchange membrane. Examples of the fluorine-based cation exchange membrane include "Nafion" (registered trademark, perfluorocarbon sulfonic acid (PFSA) membrane, manufactured by DuPont), "F-1850" (manufactured by FuMA-Tech), and the like. The thickness of the ion exchange membrane 53 is preferably 5 to 100 μm. When "Nafion" having a thickness of 50 μm is used as the ion exchange membrane 53, the ends of the ion exchange membrane 53 can be heat welded to each other at 180 ° C. When "F-1850" having a thickness of 50 μm is used as the ion exchange membrane 53, the ends of the ion exchange membrane 53 can be heat welded to each other at 200 ° C.
The adhesive layer 54 at the portion where the tab 51a of the ion exchange membrane 53 protrudes is made of a substance capable of adhering the tab 51a to the ion exchange membrane 53 due to an anchor effect, physical interaction, chemical interaction, or the like. For example, an acrylic resin or an epoxy resin can be used.

An electrolytic solution is injected into the bag-shaped ion exchange membrane 53. As the electrolytic solution, an organic solvent in which a lithium salt that conducts lithium ions is dissolved is used. A solution in which lithium polysulfide is dissolved may be used as the electrolytic solution on the positive electrode side. Examples of the Li salt include lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium bis (fluorosulfonyl) imide (LiFSI), lithium trifluoromethanesulfonate, lithium tetrafluoroborate (LiBF ₄ ), and lithium hexafluorophosphate (LiPF). ₆ ), lithium bis (pentafluoroethanesulfonyl) imide (LiBETI), lithium perchlorate and the like can be mentioned. Examples of the organic solvent include glyme-based (ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme), diethylene glycol diethyl ether (ethyl diglyme), diethylene glycol dibutyl ether. (Butyl Diglime)), tetrahydrofuran (THF), N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (DMC) EMC), propylene carbonate (PC), 1,3-dioxolane (DOL), fluoroethylene carbonate (FEC), vinylene carbonate (VC), or a mixture thereof.

The electrode material 6 of the negative electrode includes a rectangular plate-shaped current collector 61 and a square flat plate-shaped electrode 62 provided on both planes of the current collector 61.
The electrode material 7 of the negative electrode includes a rectangular plate-shaped current collector 71 and a square flat plate-shaped electrode 72 provided on one plane of the current collector 71.
The electrodes 62 and 72 are made of metallic lithium.
Alternatively, the electrodes 62 and 72 have graphite, Si, SiO, a composite of Si and carbon, or a mixture of graphite and Si or SiO, a binder, and carbon. In this case, lithium may be pre-doped in advance. Examples of the binder include SBR, CMC, fluororesins (PVDF, PVDF-HEP, PTFE), polyimide, polyamide-imide, sodium alginate, polyacrylic acid, polyethylene oxide and the like.
A porous polyolefin film or a glass separator may be provided on the electrodes 62 and 72 as a liquid-retaining layer.
Examples of the current collectors 61 and 71 include copper foil, carbon-coated copper foil, stainless steel foil, and the like, and perforated foil having holes in them. When the electrodes 62 and 72 are made of metallic lithium, a stainless mesh may be used as the current collectors 61 and 71.
The tab 61a protrudes from a part of the peripheral edge of the current collector 61. The current collector 61 and the tab 61a may be integrally formed or may be formed separately. The tab 71a protrudes from a part of the peripheral edge of the current collector 71. The current collector 71 and the tab 71a may be integrally formed or may be formed separately.

As shown in FIG. 2, the electrode material 7, the electrode material 5, the electrode material 6, the electrode material 5, and the electrode material 7 are arranged in this order from the left side of FIG. A porous separator 73 is interposed between the electrode 72 and the ion exchange membrane 53, and a porous separator 63 is interposed between the electrode 62 and the ion exchange membrane 53. Examples of the separators 63 and 73 include separators made of synthetic resin such as PP (polypropylene) and PE (polyethylene), glass separators and the like. A separator made of synthetic resin is preferable from the viewpoint of good flexibility when expanding and contracting.
The plane area of the separators 63 and 73 is preferably larger than the plane area of the electrodes 62 and 72 and smaller than the plane area of the ion exchange membrane 53. As a result, for example, when the ion exchange membrane 53 is made of PFSA, the PTFE skeleton in the PFSA comes into contact with the electrodes 62 and 72 and is reduced and decomposed to prevent defluorination.
The separator 63 facing one side surface of the ion exchange membrane 53 and the separator 73 facing the other side surface of the ion exchange membrane 53 may be integrated.

The tab 51a of one electrode material 5 extends upward, the tab 51a of the other electrode material 5 extends upward, then bends and extends toward one electrode material 5, and the positive electrode is in a state where the ends are overlapped. It is joined to the terminal 3. The positive electrode terminal 3 protrudes from a part of the peripheral edge of the exterior body 2, and the positive electrode terminal 3 is adhered to the exterior body 2 via the adhesive layer 30. The positive electrode terminal 3 may be adhered to the exterior body 2 with the central portion covered with the sealant.
The tab 61a of the electrode material 6 extends downward, and the tabs 71a and 71a of the electrode materials 7 and 7 extend downward and then bend and extend toward the electrode material 6, and the ends thereof are overlapped with each other. , Bonded to the negative electrode terminal 4. The negative electrode terminal 4 protrudes from a part of the peripheral edge of the exterior body 2, and the negative electrode terminal 4 is adhered to the exterior body 2 via the adhesive layer 40. The negative electrode terminal 4 may be adhered to the exterior body 2 with the central portion covered with the sealant.

The exterior body 2 is an insulating film that is impermeable to the electrolytic solution. The exterior body 2 is preferably made of a laminated sheet having a three-layer structure of a synthetic resin layer, a metal layer, and a synthetic resin layer. The exterior body 2 is made by combining two laminated sheets. A single laminated sheet may be bent at the center in the longitudinal direction to align the ends.
Examples of the material of the synthetic resin layer include polyamides such as polypropylene, polyethylene, nylon 6, and nylon 66. Examples of the material of the metal layer include aluminum, aluminum alloy, copper, copper alloy, iron, stainless steel, titanium, and titanium alloy.
The thickness of the exterior body 2 is not particularly limited, but is preferably 15 to 250 μm. When the thickness is 15 to 250 μm, the strength is sufficient and the volumetric energy density of the battery is improved.
An electrolytic solution is injected into the exterior body 2.

Hereinafter, a method for manufacturing the battery 1 according to the present embodiment will be described.
The active material of the positive electrode, carbon, binder and, if necessary, a lubricant are kneaded to obtain a kneaded product. The kneaded material is provided on both planes of the current collector 51 at equal intervals in the extending direction of the planes. The current collector 51 is cut between adjacent kneaded materials and dried to obtain an electrode material having electrodes 52 on both planes. The electrode material is sandwiched between two sheet-shaped ion exchange membranes in a state where the tab 51a of the current collector 51 protrudes from the peripheral portion, and the portion other than the portion where the tab 51a protrudes is adhered by heat welding to form a bag. To obtain the ion exchange membrane 53 of. The portion where the tab 51a protrudes is bonded by providing an adhesive layer 54 with an adhesive. As a result, the electrode material 5 in which the exposed portions of the side surface and the flat surface of the electrode 52 and the side surface and the flat surface of the current collector 51 are covered with the ion exchange membrane 53 can be obtained. Before adhering the entire circumference of the ion exchange membrane 53, the electrolytic solution is injected from this portion, leaving a portion.

Metallic lithium or a composite of graphite, Si, SiO, Si and carbon, or a mixture of graphite and Si or SiO, a binder, and carbon on both planes of the current collector 61 at equal intervals in the extending direction of the plane. The kneaded material having is provided at equal intervals. The current collector 61 is cut between adjacent kneaded materials and dried to obtain an electrode material 6 having electrodes 62 on both planes. Similarly, an electrode material 7 having an electrode 72 provided on one plane of the current collector 71 is obtained. When an electrode material that does not contain lithium is used, the electrode materials 6 and 7 and the metal lithium foil may be bonded in advance.

With the separator 73 interposed between the electrode 72 and the ion exchange membrane 53 and the separator 63 interposed between the electrode 62 and the ion exchange membrane 53, the electrode material 7, the electrode material 5, the electrode material 6, and the electrode The material 5 and the electrode material 7 are arranged.
The electrode material 7, the electrode material 5, the electrode material 6, the electrode material 5, and the electrode material 7 are sandwiched between two sheet-shaped laminated films, and the peripheral portion is left and bonded by heat welding to form a bag-shaped exterior body. Form 2. The protruding portions of the positive electrode terminal 3 and the negative electrode terminal 4 are bonded via the adhesive layers 30 and 40. After injecting the electrolytic solution from the remaining portion of the peripheral portion, the portion is sealed.
The battery 1 is manufactured as described above.

In the battery 1 configured as described above, since the electrode 52 of the electrode material 5 is covered with the ion exchange membrane 53, the electrode 52 and the electrode 72, and the electrode 52 and the electrode 62 are well separated, and the charge / discharge capacity is satisfactorily separated. And the decrease in charge / discharge efficiency can be suppressed.

Embodiment 2.
The battery 10 according to the second embodiment has the same configuration as the battery 1 according to the first embodiment, except that the configuration of the electrode material 8 of the negative electrode is different from the configuration of the electrode material 6 of the negative electrode.
FIG. 5 is a schematic cross-sectional view showing the battery 10. In FIG. 5, the same parts as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.
The electrode material 8 includes a rectangular plate-shaped current collector 81, a square flat plate-shaped electrode 82 provided on both planes of the current collector 81, and a separator 83. The materials of the current collector 81, the electrode 82, and the separator 83 are the same as the materials of the current collector 61, the electrode 62, and the separator 63.
The separator 83 covers the side surface and the flat surface of the electrode 82, and the exposed portion of the side surface and the flat surface of the current collector 81. The separator 83 has a bag shape, and the current collector 81 and the electrode 82 are housed inside the bag shape. The separator 83 has a bag shape by adhering the peripheral edges of two sheet-shaped separators. The separator 83 may be formed into a bag shape by bending one rectangular separator at the center portion in the longitudinal direction and aligning the ends thereof.

The tab 81a protrudes from a part of the peripheral edge of the current collector 81. The tab 81a protrudes from a part of the peripheral edge of the separator 83 and is adhered to the separator 83 via the adhesive layer 84. The ends of the separator 83 other than the protruding portion of the tab 81a are bonded to each other by the adhesive layer 84. Examples of the material of the adhesive layer 84 include an acrylic resin and an epoxy resin. When the separator is a thermoplastic resin such as polypropylene or polyethylene, the separators may be heat-welded to each other. In this case, the adhesive layer 84 may be omitted.
The tab 81a of the electrode material 8 extends downward, and the tabs 71a and 71a of the electrode materials 7 and 7 extend downward and then bend and extend toward the electrode material 8 so that their ends are overlapped with each other. , Bonded to the negative electrode terminal 4. The negative electrode terminal 4 protrudes from a part of the peripheral edge of the exterior body 2, and the negative electrode terminal 4 is adhered to the exterior body 2 via the adhesive layer 40. The negative electrode terminal 4 may be adhered to the exterior body 2 with the central portion covered with the sealant. The current collector 81 and the tab 81a may be integrally formed or may be formed separately.

In the present embodiment, since the electrode material 8 of the negative electrode is also packaged together with the electrode material 5 of the positive electrode, the assembleability when laminating the electrode materials 5, 8 and 5 is good.
The separator 83 may be covered with a cation exchange membrane. Then, the ion exchange membrane may be integrated with the separator 83. In this case, the plane area of the ion exchange membrane is made larger than the plane area of the separator 83, and the ends of the ion exchange membrane are heat-welded to each other to form a bag.

Embodiment 3.
The battery 12 according to the third embodiment has the same configuration as the battery 1 according to the first embodiment, except that the current collector has a different configuration and has a lithium supply member 9 for predoping.
FIG. 6 is a schematic cross-sectional view showing the battery 12. In FIG. 6, the same parts as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.
The current collector 55 of the electrode material 5 of the positive electrode has a plurality of through holes 55a in a portion facing the electrode 52. The current collectors 64 and 74 of the electrode materials 6 and 7 of the negative electrode have a plurality of through holes 64a and 74a in the portions facing the electrodes 62 and 72.

The tab 55b of one electrode material 5 extends upward, the tab 55b of the other electrode material 5 extends upward, then bends and extends toward one electrode material 5, and the positive electrode is in a state where the ends are overlapped. It is joined to the terminal 3. The tab 64b of the electrode material 6 extends downward, and the tabs 74b and 74b of the electrode materials 7 and 7 extend downward and then bend and extend toward the electrode material 6, and the ends thereof are overlapped with each other. , Bonded to the negative electrode terminal 4.
In the battery 12, the lithium supply member 9 is adjacent to the electrode material 7. The lithium supply member 9 has a conductive material 91 made of copper foil or stainless steel foil, a lithium foil 92, and a separator 93. The terminal 91a protruding from a part of the peripheral edge of the conductive material 91 extends downward and protrudes from a part of the peripheral edge of the exterior body 2, and the end portion of the terminal 91a is bonded to the exterior body 2 via the adhesive layer 94. Has been done. The end portion of the terminal 91a may be adhered to the exterior body 2 with the central portion covered with the sealant.
A separator 93 is interposed between the lithium foil 92 and the current collector 74 of the electrode material 7. As the material of the separator 93, the same material as that of the separator 73 can be used.

According to this embodiment, when the active material of the negative electrode is graphite, Si, SiO, a composite of Si and carbon, or a mixture of graphite and Si or SiO, the lithium foil 92 and the electrode 72 are short-circuited. As a result, lithium can be easily pre-doped. As electrons flow from the lithium foil 92 to the electrode 72, lithium ions are released into the electrolytic solution, and the lithium ions pass through the through holes 55a, 64a, 74a of the current collectors 55, 64, 74 and diffuse to the negative electrode. It is doped into the electrodes 62 and 72 of.
The current collectors 55, 64, and 74 may have a mesh structure. Examples of cases where the current collectors 55, 64, and 74 have a mesh structure include expanded metal and wire mesh. The lithium supply member 9 may be taken out at the time of resealing.

Embodiment 4.
The battery 13 according to the fourth embodiment has a different laminated structure of the electrode materials from the battery 1 according to the first embodiment.
FIG. 7 is a schematic cross-sectional view showing the battery 13. In FIG. 7, the same parts as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.
The battery 13 includes a positive electrode material 5 and negative electrode materials 7, 7. The configurations of the electrode material 5 and the electrode material 7 are the same as the configurations of the electrode material 5 and the electrode material 7 according to the first embodiment.
In the battery 13, the electrode material 7, the electrode material 5, and the electrode material 7 are arranged in order from the left side of FIG. 7.
The tab 51a of the electrode material 5 extends upward and is joined to the positive electrode terminal 3. The positive electrode terminal 3 protrudes from a part of the peripheral edge of the exterior body 2, and the positive electrode terminal 3 is adhered to the exterior body 2 via the adhesive layer 30. The positive electrode terminal 3 may be adhered to the exterior body 2 with the central portion covered with the sealant.
The tab 71a of one electrode material 7 extends downward, the tab 71a of the other electrode material 7 extends downward, then bends and extends toward one electrode material 7, and the ends are overlapped with each other. , Bonded to the negative electrode terminal 4. The negative electrode terminal 4 protrudes from a part of the peripheral edge of the exterior body 2, and the negative electrode terminal 4 is adhered to the exterior body 2 via the adhesive layer 40. The negative electrode terminal 4 may be adhered to the exterior body 2 with the central portion covered with the sealant.
In the battery 13 configured as described above, since the electrode 52 of the electrode material 5 of the positive electrode is covered with the ion exchange membrane 53, the electrode 52 and the electrode 72 are well separated, and the charge / discharge capacity and charge / discharge efficiency are satisfactorily separated. Can be suppressed.

Embodiment 5.
The battery 16 according to the fifth embodiment has the same configuration as the battery 1 according to the first embodiment, except that the electrode material 11 of the negative electrode has a bag-shaped ion exchange membrane 113.
FIG. 8 is a schematic cross-sectional view showing the battery 16. In FIG. 8, the same parts as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. In the battery 16, the positive electrode material 14, the negative electrode material 11, the positive electrode material 15, the electrode material 11, and the electrode material 14 are arranged in this order.

The electrode material 11 of the negative electrode has a current collector 111, an electrode 112, an ion exchange membrane 113, and a separator 114.
The current collector 111 has a rectangular plate shape, and square flat plate-shaped electrodes 112 are provided on both planes. The ion exchange membrane 113 covers the side surface and the flat surface of the electrode 112, and the exposed portion of the side surface and the flat surface of the current collector 111. The ion exchange membrane 113 has a bag shape by adhering the peripheral portions of two sheet-shaped ion exchange membranes. The ion exchange membrane 113 may be formed into a bag shape by bending a single rectangular ion exchange membrane at the central portion in the longitudinal direction and aligning the ends thereof. A separator 114 is interposed between the outer surface of the electrode 112 and the ion exchange membrane 113. The plane area of the separator 114 is larger than the plane area of the electrode 112 and smaller than the plane area of the ion exchange membrane 113. The materials of the current collector 111, the electrode 112, the ion exchange membrane 113, and the separator 114 are the same as the materials of the current collector 61, the electrode 62, the ion exchange membrane 53, and the separator 63. The ion exchange membrane 113 and the separator 114 may be integrated.

The electrode material 14 of the positive electrode includes a rectangular plate-shaped current collector 141 and a square flat plate-shaped electrode 142 provided on one plane of the current collector 141.
The electrode material 15 for the positive electrode includes a rectangular plate-shaped current collector 151 and a square flat plate-shaped electrode 152 provided on both planes of the current collector 151.
The materials of the members of the electrode materials 14 and 15 are the same as the materials of the members of the electrode material 5.

The tab 111a protrudes from a part of the peripheral edge of the current collector 111. The tab 111a protrudes from a part of the peripheral edge of the ion exchange membrane 113 and is adhered to the ion exchange membrane 113 via the adhesive layer 115. The ends of the ion exchange membrane 113 other than the protruding portion of the tab 111a are bonded to each other by heat welding. Examples of the material of the adhesive layer 115 include acrylic resin and epoxy resin. The current collector 111 and the tab 111a may be integrally formed or may be formed separately.
The tab 111a of one electrode material 11 extends upward, the tab 111a of the other electrode material 11 extends upward, then bends and extends toward one electrode material 11, and the negative electrode is in a state where the ends are overlapped. It is joined to the terminal 4. The negative electrode terminal 4 protrudes from a part of the peripheral edge of the exterior body 2, and the negative electrode terminal 4 is adhered to the exterior body 2 via the adhesive layer 40. The negative electrode terminal 4 may be adhered to the exterior body 2 with the central portion covered with the sealant.
Tabs 141a and 151a project from a part of the peripheral edges of the current collectors 141 and 151 of the electrode materials 14 and 15. The tabs 151a of the electrode material 15 extend downward, the tabs 141a and 141a of the electrode materials 14 and 14 extend downward, then bend and extend toward the electrode material 15, and the ends thereof are overlapped with each other. , Bonded to the positive electrode terminal 3. The positive electrode terminal 3 protrudes from a part of the peripheral edge of the exterior body 2, and the positive electrode terminal 3 is adhered to the exterior body 2 via the adhesive layer 30. The positive electrode terminal 3 may be adhered to the exterior body 2 with the central portion covered with the sealant. The current collectors 141, 151 and the tabs 141a, 151a may be integrally formed or may be formed separately.

In the battery 16 configured as described above, since the electrode 112 of the electrode material 11 of the negative electrode is covered with the ion exchange film 113, the electrode 112 and the electrode 142 and the electrode 112 and the electrode 152 are well separated and charged. It is possible to suppress a decrease in discharge capacity and charge / discharge efficiency.
Since the separator 114 is arranged on the inner surface of the ion exchange membrane 113, it is suppressed that the ion exchange membrane 113 and the electrode 112 come into direct contact with each other to decompose the ion exchange membrane 113. Since the plane area of the separator 114 is larger than the plane area of the electrode 112 and smaller than the plane area of the ion exchange membrane 113, the above-mentioned decomposition can be satisfactorily suppressed and the ends of the ion exchange membrane 113 can be heat-welded to each other. ..

The battery according to the present invention can be laminated by combining an appropriate number of positive electrode materials and negative electrode materials. As the electrode material of the positive electrode and the negative electrode, a material in which the electrodes are provided on one plane of the current collector and a material in which the electrodes are provided on both planes of the current collector can be combined. The energy density of the battery can be improved by laminating a plurality of positive electrode materials and negative electrode materials.

As described above, the lithium sulfur battery according to one aspect of the present invention is provided on each plane of the flat plate-shaped first current collector and the first current collector, and has two first electrodes having the same polarity. , And the first electrode material having a bag-shaped cation exchange film accommodating the first current collector and the first electrode, the flat plate-shaped second current collector, and the cation exchange film. A second electrode material provided on a plane of the second current collector facing the first electrode and having a second electrode having a polarity different from that of the first electrode is provided, and the first electrode and the second electrode are provided. One of them is a positive electrode having an active material containing sulfur, and the other is a negative electrode having an active material containing lithium.

According to the above configuration, since the first electrode of the first electrode material is covered with the ion exchange membrane, the positive electrode and the negative electrode can be well separated, and the decrease in charge / discharge capacity and charge / discharge efficiency can be suppressed. ..

In the above-mentioned lithium-sulfur battery, the second electrode material has two second electrodes on both planes of the second current collector, and the first electrode material and the second electrode material are laminated. May be.

According to the above configuration, a plurality of positive electrodes and negative electrodes can be laminated to increase the energy density.

In the above-mentioned lithium-sulfur battery, a porous separator may be provided between the cation exchange membrane and the negative electrode adjacent to the cation exchange membrane.

According to the above configuration, the cation exchange membrane and the negative electrode are in direct contact with each other to prevent the cation exchange membrane from being decomposed.

In the above-mentioned lithium-sulfur battery, the second electrode is a negative electrode, and the second electrode material may include the second current collector and the bag-shaped porous separator accommodating the second electrode. ..

According to the above configuration, direct contact between the cation exchange membrane and the negative electrode prevents the cation exchange membrane from decomposing. Further, the assembleability when laminating the first electrode material and the second electrode material is good.

In the above-mentioned lithium-sulfur battery, the separator may be made of synthetic resin.

According to the above configuration, the flexibility when expanding or contracting is good.

In the above-mentioned lithium-sulfur battery, the plane area of the separator may be smaller than the plane area of the cation exchange membrane and may be larger than the plane area of the negative electrode.

According to the above configuration, the peripheral edge portion of the cation exchange membrane can be adhered by heat welding. The cation exchange membrane can be easily and surely made into a bag. Then, the contact between the cation exchange membrane and the negative electrode is satisfactorily prevented.

In the above-mentioned lithium-sulfur battery, the cation exchange membrane may be a fluorine-based cation exchange membrane.

According to the above configuration, it is physically and chemically stable.

In the above-mentioned lithium-sulfur battery, the end portion of the cation exchange membrane is sealed by heat welding, and the thickness of the cation exchange membrane may be 5 to 100 μm.

According to the above configuration, the ends of the cation exchange membrane can be easily bonded to each other by heat welding.

In the above-mentioned lithium-sulfur battery, the first current collector or the second current collector may have a plurality of through holes.

According to the above configuration, the negative electrode can be easily pre-doped with lithium.

In the above-mentioned lithium-sulfur battery, the first current collector or the second current collector may have a network structure.

According to the above configuration, the negative electrode can be easily pre-doped with lithium.

In the above-mentioned lithium-sulfur battery, in the first electrode material, a tab protruding from a part of the peripheral edge of the first current collector protrudes from a part of the peripheral edge of the cation exchange membrane, and the tab is the positive. It may be adhered to the ion exchange membrane via an adhesive layer.

The cation exchange membrane and the tab cannot be directly bonded. According to the above configuration, the cation exchange membrane and the tab are adhered by the adhesive layer.

The method for manufacturing a lithium sulfur battery according to one aspect of the present invention is a method for manufacturing a lithium sulfur battery having a positive electrode having an active material containing sulfur and a negative electrode having an active material containing lithium, and is a flat plate-shaped first. Two first electrodes having the same polarity are provided on each plane of one current collector, and the first current collector provided with the first electrode is covered with a cation exchange film, and the cation exchange film is provided. The first electrode material is manufactured by adhering the ends, and the second electrode material having a polarity different from that of the first electrode is provided on the plane of the flat plate-shaped second current collector to prepare the second electrode material. The first electrode material and the second electrode material are arranged so that the first electrode and the second electrode face each other, and the first electrode material and the second electrode material are covered with an exterior body.

According to the above configuration, a positive electrode and a negative electrode can be satisfactorily separated by an ion exchange membrane without using a pressure-sensitive adhesive and a sealant, and a lithium-sulfur battery having good charge / discharge capacity and charge / discharge efficiency can be obtained.

The present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims. That is, an embodiment obtained by combining technical means appropriately modified within the scope of the claims is also included in the technical scope of the present invention.
The material, configuration, and number of each electrode material, the polarity of the electrodes, the method of adhering the ion exchange membrane and the exterior body, and the like are not limited to the cases described in the first to fifth embodiments.

The case is not limited to the case where the first electrode material and the second electrode material are laminated to form a battery. A plurality of positive electrodes are intermittently provided on the flat surface of the current collector to obtain a positive electrode material, and a plurality of negative electrodes are intermittently provided on the flat surface of the current collector to obtain a negative electrode material. An ion exchange film is interposed in a state where the electrodes of the electrode material face each other, and the two electrode materials and the ends of the ion exchange film are adhered to obtain an electrode unit. By folding the electrode unit in a zigzag manner so that the electrodes are lined up in one direction, the electrode unit may be covered in a bag shape by an ion exchange membrane with the two positive electrodes facing each other across the current collector. Similarly, the two negative electrodes are covered with an ion exchange membrane in a bag shape with the two negative electrodes facing each other across the current collector. Instead of folding the electrode unit in a zigzag manner, the above-mentioned configuration may be obtained by winding the electrode unit.

1, 10, 12, 13, 16 Lithium-sulfur battery 2 Exterior 3 Positive electrode terminal 4 Negative electrode terminal 5, 6, 7, 8, 11, 14, 15 Electrode material 51, 55, 61, 64, 71, 74, 81, 111, 141, 151 Collectors 51a, 55b, 61a, 64b, 71a, 74b, 81a, 111a, 141a, 151a Tabs 52, 62, 72, 82, 112, 142, 152 Electrodes 53, 113 Ion exchange membrane 54, 84, 115 Adhesive layer 63, 73, 83, 114 Separator

Claims (12)

Flat plate-shaped first current collector,
A second electrode provided on each plane of the first current collector and having the same polarity, and a bag-shaped cation exchange membrane accommodating the first collector and the first electrode. 1 electrode material and
A second electrode provided on the plane of the flat plate-shaped second collector and the second current collector facing the first electrode via the cation exchange membrane and having a polarity different from that of the first electrode. With a second electrode material that has
A lithium-sulfur battery in which one of the first electrode and the second electrode is a positive electrode having an active material containing sulfur, and the other is a negative electrode having an active material containing lithium. The second electrode material has two second electrodes on both planes of the second current collector.
The lithium-sulfur battery according to claim 1, wherein the first electrode material and the second electrode material are laminated. The lithium-sulfur battery according to claim 1 or 2, which has a porous separator between the cation exchange membrane and the negative electrode adjacent to the cation exchange membrane. The second electrode is a negative electrode and has a negative electrode.
The lithium-sulfur battery according to claim 3, wherein the second electrode material includes the second current collector and the bag-shaped porous separator accommodating the second electrode. The lithium-sulfur battery according to claim 3 or 4, wherein the separator is made of a synthetic resin. The lithium-sulfur battery according to any one of claims 3 to 5, wherein the plane area of the separator is smaller than the plane area of the cation exchange membrane and larger than the plane area of the negative electrode. The lithium-sulfur battery according to any one of claims 1 to 6, wherein the cation exchange membrane is a fluorine-based cation exchange membrane. The end of the cation exchange membrane is sealed by heat welding.
The lithium-sulfur battery according to any one of claims 1 to 7, wherein the cation exchange membrane has a thickness of 5 to 100 μm. The lithium-sulfur battery according to any one of claims 1 to 8, wherein the first current collector or the second current collector has a plurality of through holes. The lithium-sulfur battery according to any one of claims 1 to 9, wherein the first current collector or the second current collector has a network structure. In the first electrode material, a tab protruding from a part of the peripheral edge of the first current collector protrudes from a part of the peripheral edge of the cation exchange membrane, and the tab has an adhesive layer on the cation exchange membrane. The lithium-sulfur battery according to any one of claims 1 to 10, which is bonded via the lithium-sulfur battery. A method for manufacturing a lithium-sulfur battery having a positive electrode having an active material containing sulfur and a negative electrode having an active material containing lithium.
Two first electrodes having the same polarity are provided on each plane of the flat plate-shaped first current collector.
The first current collector provided with the first electrode is covered with a cation exchange membrane, and the ends of the cation exchange membrane are adhered to prepare a first electrode material.
A second electrode material having a polarity different from that of the first electrode is provided on a flat surface of a flat plate-shaped second current collector to prepare a second electrode material.
The first electrode material and the second electrode material are arranged so that the first electrode and the second electrode face each other.
A method for manufacturing a lithium-sulfur battery in which the first electrode material and the second electrode material are covered with an exterior body.

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