Battery

Abstract

A battery 1 includes a laminate cell 10, a housing 11, and a sealing body 12. The laminate cell 10 has a positive electrode lead 4 and a negative electrode lead 5. The housing 11 accommodates the laminate cell 10. The housing 11 has an opening 111 through which the positive electrode lead 4 and the negative electrode lead 5 pass. The sealing body 12 seals the opening 111 of the housing 11. The sealing body 12 is made of a porous body having air permeability.

Description

battery

[0001] The present invention relates to a battery.

[0002] 2. Description of the Related Art Conventionally, a battery including a laminate cell and a metal case that houses the laminate cell has been known.

[0003] For example, a solid-state lithium-ion battery has been disclosed that includes a laminate as a power generating element, a first container that houses the laminate, a terminal connected to the laminate and extending outside the first container, and a second container that houses the first container. The laminate includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer. The first container is made of a first film and a second film. The second container has a metal body and a metal lid. The lid has a hole through which the terminal passes. The lid is hermetically fixed to the body by welding, adhesive, or the like. The gap between the terminal and the hole is filled with a filler material (see Patent Document 1 below).

[0004] Japanese Patent Application Laid-Open No. 2022-81801

[0005] When a solid-state lithium-ion battery such as that described in Patent Document 1 is used in a vacuum environment, the gas inside the second container may expand, causing the second container to deform.

[0006] The present invention provides a battery that can suppress deformation of the casing when the battery is used in a vacuum environment.

[0007] The present invention [1] includes a battery comprising: a laminated cell having leads; a housing having an opening through which the leads pass and containing the laminated cell; and a sealing body made of a porous body having air permeability and sealing the opening of the housing.

[0008] According to this configuration, the sealing member that seals the opening of the housing is made of a porous material that has air permeability.

[0009] Therefore, when the battery is used in a vacuum environment, the gas inside the housing passes through the sealing member and is discharged to the outside of the housing.

[0010] As a result, when the battery is used in a vacuum environment, deformation of the housing due to expansion of the gas inside the housing can be suppressed.

[0011] The present invention [2] includes the battery according to the above [1], wherein the laminate cell comprises a cell having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, a current collector laminated on the cell, a laminate film covering the laminate of the cell and the current collector, and the lead connected to the current collector, at least a portion of which is exposed from the laminate film.

[0012] The present invention [3] includes the battery according to the above [1] or [2], wherein the housing is made of metal and the sealing body is made of the insulating porous body.

[0013] With this configuration, the rigidity of the housing can suppress expansion of the laminate cell, while the sealing member can insulate the leads from the housing.

[0014] The present invention [4] includes the battery of any one of the above [1] to [3], wherein the sealing body has a slit through which the lead passes and is adhered to the inner surface of the opening.

[0015] With this configuration, the battery can be manufactured through a simple process of housing the laminated cell in the housing, inserting the sealing body into the opening of the housing while passing the leads through the slits, and then adhering the sealing body to the inner surface of the opening.

[0016] Therefore, the efficiency of battery production can be improved.

[0017] According to the battery of the present invention, deformation of the casing can be suppressed when the battery is used in a vacuum environment.

[0018] FIG. 1A is a perspective view of a battery according to one embodiment of the present invention. FIG. 1B is an exploded view of the battery shown in FIG. 1A. FIG. 2A is a plan view of the laminate cell shown in FIG. 1B. FIG. 2B is an A-A cross-sectional view of the laminate cell shown in FIG. 2A. FIG. 3A is a cross-sectional view showing the layer structure of the cell shown in FIG. 2B. FIG. 3B is an enlarged view of the laminate cell shown in FIG. 2B. FIG. 4A is a plan view of the positive electrode current collector shown in FIG. 3B. FIG. 4B is a B-B cross-sectional view of the positive electrode current collector shown in FIG. 4A. FIG. 5 is a C-C cross-sectional view of the laminate cell shown in FIG. 2A.

[0019] 1A and 1B, the battery 1 includes a laminate cell 10, a housing 11, and a sealing body 12. The battery 1 is an all-solid-state battery that uses a solid electrolyte as the electrolyte.

[0020] (1) Laminated Cell As shown in FIGS. 2A and 2B , a laminated cell 10 includes a plurality of cells 2, a plurality of current collectors 3, a positive electrode lead 4 as an example of a lead, a negative electrode lead 5 as an example of a lead, and a laminated film 6.

[0021] (1-1) Cell In this embodiment, the cell 2 has a sheet shape. When viewed from the thickness direction of the cell 2, the cell 2 has a substantially rectangular shape. The shape of the cell 2 is not limited. The cell 2 may have a plate shape or a film shape. Furthermore, the cell 2 may have a substantially circular shape when viewed from the thickness direction of the cell 2.

[0022] The thickness of the cell 2 is, for example, 100 μm or more, preferably 200 μm or more, and for example, 1000 μm or less, preferably 800 μm or less.

[0023] 3A , the cell 2 has a positive electrode layer 21, a negative electrode layer 22, and a solid electrolyte layer 23. The cell 2 does not have a current collector. The cell 2 is composed of the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23. The cell 2 is a bare cell independent of the current collector 3. However, the cell 2 may be integrated with the current collector 3.

[0024] (1-1-1) Positive Electrode Layer The positive electrode layer 21 is disposed away from the negative electrode layer 22 in the thickness direction of the cell 2. The positive electrode layer 21 is disposed on the opposite side of the solid electrolyte layer 23 from the negative electrode layer 22 in the thickness direction of the cell 2. The positive electrode layer 21 is in contact with the solid electrolyte layer 23 but is not in contact with the negative electrode layer 22.

[0025] The positive electrode layer 21 is made of a powder containing a positive electrode active material. In this embodiment, the positive electrode layer 21 does not contain a resin such as a binder. In this embodiment, the positive electrode layer 21 is made of a mixture of a powder of the positive electrode active material and a powder of a solid electrolyte. The positive electrode layer 21 does not necessarily have to contain the solid electrolyte. The positive electrode layer 21 may be made of only the positive electrode active material.

[0026] The positive electrode active material may be, for example, a lithium-containing oxide. Examples of the lithium-containing oxide include lithium-nickel composite oxide (LiNi X M 1-X O2), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium nickel cobalt aluminum composite oxide (LiNi 0.8 Co 0.15 Al 0.05 O2, NCA-based layered oxide), lithium manganate (spinel-type lithium manganate (LiMn2O4)), and Li-excess composite oxide (Li2MnO3-LiMO2).

[0027] The positive electrode active material is not limited to lithium-containing oxides as long as it is capable of inserting and extracting lithium ions. Examples of the positive electrode active material include olivine-based compounds (LiMPO4) and sulfur-containing compounds (Li2S).

[0028] In the above chemical formula, M represents a transition metal.

[0029] As the positive electrode active material, a lithium-containing oxide containing at least one selected from the group consisting of Co, Ni, and Mn is preferable, from the viewpoint of easily obtaining a high capacity.

[0030] In addition, the surface of the positive electrode active material may be covered with a coating material from the viewpoint of improving rate characteristics.

[0031] As a coating material, for example, Li4Ti5O 12 , LiTaO3, Li4NbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, LiBO2, alumina (Al2O3), and carbon (C).

[0032] The positive electrode active materials can be used alone or in combination of two or more kinds.

[0033] The solid electrolyte exhibits lithium ion conductivity. Examples of the solid electrolyte include organic solid electrolytes and inorganic solid electrolytes.

[0034] Inorganic solid electrolytes include, for example, sulfides, oxides, nitrides, and hydrides.

[0035] The sulfide may, for example, contain LiS and another sulfide containing at least one element selected from the group consisting of Group 13 elements, Group 14 elements, and Group 15 elements of the periodic table.

[0036] Examples of Group 13 elements, Group 14 elements, and Group 15 elements of the periodic table include P, Si, Ge, As, Sb, and Al, preferably P, Si, and Ge, and more preferably P.

[0037] Specific examples of sulfides include Li2S-SiS2, Li2S-P2S5, Li2S-GeS2, Li2S-B2S3, Li2S-Ga2S3, Li2S-Al2S3, Li2S-GeS2-P2S5, Li2S-Al2S3-P2S5, Li2S-P2S3, Li2S-P2S3-P2S5, LiX-Li2S-P2S5, LiX-Li2S-SiS2, and LiX-Li2S-B2S3 (X: I, Br, or Cl).

[0038] The solid electrolyte is preferably an inorganic solid electrolyte, more preferably a sulfide. The solid electrolyte may be used alone or in combination of two or more. The ratio of the positive electrode active material to the solid electrolyte is not limited.

[0039] The positive electrode layer 21 has a thickness of, for example, 50 μm or more, or preferably 100 μm or more. The positive electrode layer 21 has a thickness of, for example, 500 μm or less, or preferably 300 μm or less.

[0040] (1-1-2) Negative Electrode Layer The negative electrode layer 22 is disposed away from the positive electrode layer 21 in the thickness direction of the cell 2. The negative electrode layer 22 is disposed on the opposite side of the solid electrolyte layer 23 from the positive electrode layer 21 in the thickness direction of the cell 2. The negative electrode layer 22 is in contact with the solid electrolyte layer 23 but is not in contact with the positive electrode layer 21.

[0041] The negative electrode layer 22 is made of a powder containing a negative electrode active material. The negative electrode layer 22 does not contain a resin such as a binder. In this embodiment, the negative electrode layer 22 is made of a mixture of a powder of the negative electrode active material and a powder of a solid electrolyte. The negative electrode layer 22 does not necessarily have to contain the solid electrolyte. The negative electrode layer 22 may be made of only the negative electrode active material.

[0042] The negative electrode active material is not limited as long as it is a material capable of inserting and extracting lithium ions, and examples of the negative electrode active material include carbon materials, metals and alloys thereof, semimetals, and compounds of metals or semimetals.

[0043] Examples of carbon materials include graphite (natural graphite, artificial graphite), hard carbon, and amorphous carbon. Examples of metals and their alloys include lithium and its alloys. Examples of metalloids include silicon. Examples of metal or metalloid compounds include oxides, sulfides, nitrides, hydrates, and silicides (lithium silicides) of metals or metalloids. Examples of metal or metalloid oxides include titanium oxide and silicon oxide.

[0044] The negative electrode active material can be used alone or in combination of two or more thereof. For example, silicon oxide and a carbon material can be used in combination as the negative electrode active material.

[0045] Examples of the solid electrolyte contained in the anode layer 22 include the solid electrolytes described above. Preferably, the solid electrolyte contained in the anode layer 22 is the same as the solid electrolyte contained in the cathode layer 21. The ratio of the anode active material to the solid electrolyte is not limited.

[0046] The thickness of the negative electrode layer 22 is approximately the same as the thickness of the positive electrode layer 21. The thickness of the negative electrode layer 22 is, for example, 50 μm or more, or preferably 100 μm or more. The thickness of the negative electrode layer 22 is, for example, 500 μm or less, or preferably 300 μm or less.

[0047] (1-1-3) Solid Electrolyte Layer The solid electrolyte layer 23 is disposed between the positive electrode layer 21 and the negative electrode layer 22 in the thickness direction of the cell 2. The solid electrolyte layer 23 is made of solid electrolyte powder. The solid electrolyte layer 23 does not contain a resin such as a binder.

[0048] The solid electrolyte may be, for example, the solid electrolyte described above. Preferably, the solid electrolyte is the same as the solid electrolyte contained in the positive electrode layer 21.

[0049] The solid electrolyte layer 23 is thinner than the positive electrode layer 21 and the negative electrode layer 22. The thickness of the solid electrolyte layer 23 is, for example, 10 μm or more, or preferably 30 μm or more. The thickness of the solid electrolyte layer 23 is, for example, 300 μm or less, or preferably 100 μm or less.

[0050] (1-2) Current Collector As shown in FIG. 3B , the current collector 3 is stacked on the cell 2. Specifically, each of the multiple current collectors 3 is stacked alternately with each of the multiple cells 2. The multiple current collectors 3 include a positive electrode current collector 3A and a negative electrode current collector 3B. The positive electrode current collector 3A contacts the positive electrode layer 21 of the cell 2. The negative electrode current collector 3B contacts the negative electrode layer 22 of the cell 2.

[0051] Specifically, in this embodiment, the positive electrode current collector 3A, the first cell 2A, the negative electrode current collector 3B, the second cell 2B, and the positive electrode current collector 3A are stacked in this order from one side to the other in the stacking direction of the cells 2 and the current collectors 3. In the stacking direction, one negative electrode current collector 3B is disposed between the negative electrode layer 22 of the first cell 2A and the negative electrode layer 22 of the second cell 2B. In other words, one current collector 3 is disposed between two cells 2 in the stacking direction.

[0052] As shown in FIGS. 4A and 4B, the current collector 3 has a conductor 31, an insulating member 32, and an adhesive layer 33.

[0053] (1-2-1) Conductor The conductor 31 is made of, for example, a metal. The conductor 31 has a laminated portion 311 and a tab 312.

[0054] The laminated portion 311 extends in a first direction and a second direction. The first direction is perpendicular to the stacking direction. The second direction is perpendicular to both the first direction and the stacking direction. The laminated portion 311 has a sheet shape. The laminated portion 311 has one side S1 and another side S2 in the thickness direction. In other words, the conductor 31 has one side S1 and another side S2 in the thickness direction. The laminated portion 311 contacts the cell 2. When the current collector 3 is a positive electrode current collector 3A, the laminated portion 311 contacts the positive electrode layer 21 of the cell 2. When the current collector 3 is a negative electrode current collector 3B, the laminated portion 311 contacts the negative electrode layer 22 of the cell 2. When viewed from the stacking direction, the laminated portion 311 has a substantially rectangular shape. The laminated portion 311 has multiple edges E1, E2, E3, and E4.

[0055] Edge E1 is disposed at one end of stacked portion 311 in the first direction. Edge E1 extends in the second direction. Edge E1 has a linear shape. Edge E2 is disposed at the other end of stacked portion 311 in the first direction. Edge E2 extends in the second direction. Edge E2 has a linear shape. Edge E3 is disposed at one end of stacked portion 311 in the second direction. Edge E3 extends in the first direction. Edge E3 has a linear shape. Edge E4 is disposed at the other end of stacked portion 311 in the second direction. Edge E4 extends in the first direction. Edge E4 has a linear shape.

[0056] The tab 312 is disposed on an edge of the laminated portion 311. In the present embodiment, the tab 312 is disposed on an edge E3 on one side of the laminated portion 311 in the second direction. The tab 312 protrudes from the edge E3 of the laminated portion 311. The tab 312 may be a separate member from the laminated portion 311 and may be joined to the laminated portion 311. The tab 312 has a belt shape. The tab 312 does not contact the cell 2. When the current collector 3 is a positive electrode current collector 3A, the conductor 31 has a positive electrode tab 312A as the tab 312. When the current collector 3 is a negative electrode current collector 3B, the conductor 31 has a negative electrode tab 312B as the tab 312. When the cell 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are stacked, the negative electrode tab 312B is disposed away from the positive electrode tab 312A. When the cell 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are stacked, the negative electrode tab 312B does not overlap the positive electrode tab 312A in the stacking direction.

[0057] The thickness of the conductor 31 is, for example, 1 μm or more, or preferably 5 μm or more, and for example, 100 μm or less, or preferably 50 μm or less.

[0058] Examples of materials for the conductor 31 include copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), indium (In), lithium (Li), tin (Sn), and alloys thereof.

[0059] (1-2-2) Insulating Member As shown in FIG. 4B , the insulating member 32 is laminated on one surface S1 of the conductor 31. As shown in FIG. 4A , the insulating member 32 is disposed on the laminated portion 311 of the conductor 31. The insulating member 32 is laminated on the peripheral edge of the laminated portion 311 of the conductor 31. When viewed from the lamination direction, the insulating member 32 has a substantially rectangular frame shape. The insulating member 32 has a portion 32A extending along the edge E1 of the conductor 31, a portion 32B extending along the edge E2 of the conductor 31, a portion 32C extending along the edge E3 of the conductor 31, and a portion 32D extending along the edge E4 of the conductor 31. The insulating member 32 is not disposed on the tab 312 of the conductor 31.

[0060] When the cell 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are stacked, the insulating member 32 is disposed around the cell 2. As shown in Fig. 3B , when the cell 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are stacked, the insulating member 32 is disposed between the positive electrode current collector 3A and the negative electrode current collector 3B in the stacking direction. When the cell 2, the positive electrode current collector 3A, and the negative electrode current collector 3B are stacked, the insulating member 32 insulates the positive electrode current collector 3A from the negative electrode current collector 3B.

[0061] In the stacking direction, the thickness of the insulating member 32 is thinner than the thickness of the cells 2. When the current collector 3 does not have the adhesive layer 33, the thickness of the insulating member 32 may be the same as the thickness of the cells 2. The thickness of the insulating member 32 is, for example, 50 μm or more, preferably 75 μm or more, and for example, 500 μm or less, preferably 400 μm or less.

[0062] Examples of materials for the insulating member 32 include polyethylene terephthalate and polyimide.

[0063] (1-2-3) Adhesive Layer As shown in Fig. 4B, an adhesive layer 33 is laminated on the other surface S2 of the conductor 31 at the peripheral edge of the conductor 31. The current collector 3 does not need to have the adhesive layer 33. As shown in Fig. 3B, with one cell 2 stacked between two current collectors 3, the adhesive layer 33 of the current collector 3 arranged on the other side of the cell 2 in the stacking direction is adhered to the insulating member 32 of the current collector 3 arranged on one side of the cell 2 in the stacking direction.

[0064] The sum of the thickness of the adhesive layer 33 and the thickness of the insulating member 32 is equal to or less than the thickness of the cell 2. The thickness of the adhesive layer 33 is, for example, 30 μm or more, preferably 50 μm or more, and for example, 300 μm or less, preferably 200 μm or less.

[0065] The adhesive layer 33 is preferably insulating. Examples of materials for the adhesive layer 33 include resins such as acrylic, polyimide, and silicone, and nonwoven fabrics impregnated with these resins.

[0066] (1-3) Positive Electrode Lead and Negative Electrode Lead As shown in FIG. 2A, a portion of the positive electrode lead 4 is exposed from the laminate film 6. As shown in FIG. 5, the positive electrode lead 4 is joined to the positive electrode tab 312A within the laminate film 6. This electrically connects the positive electrode lead 4 to the positive electrode current collector 3A. The positive electrode lead 4 is not connected to the negative electrode current collector 3B.

[0067] As shown in Fig. 2A , a portion of the negative electrode lead 5 is exposed from the laminate film 6. The negative electrode lead 5 is joined to the negative electrode tab 312B (see Fig. 4A ) within the laminate film 6. This electrically connects the negative electrode lead 5 to the negative electrode current collector 3B (see Fig. 2B ). The negative electrode lead 5 is not connected to the positive electrode current collector 3A.

[0068] The positive electrode lead 4 and the negative electrode lead 5 each have, for example, a substantially rectangular flat plate shape. Examples of materials for the positive electrode lead 4 and the negative electrode lead 5 include pure metals and alloys. Examples of pure metals include copper, nickel, aluminum, gold, and platinum. Examples of alloys include alloys of the above pure metals, stainless steel, and titanium. The positive electrode lead 4 and the negative electrode lead 5 may be plated. For example, the positive electrode lead 4 and the negative electrode lead 5 may be copper plates having a nickel-plated layer and a gold-plated layer.

[0069] 2A and 2B, a laminate film 6 covers the laminate of the cells 2 and the current collectors 3. The laminate of the cells 2 and the current collectors 3 is vacuum laminated. An example of the laminate film 6 is a metal laminate film in which resin films are laminated on both sides of a metal foil.

[0070] (2) Housing As shown in FIG. 1B , the housing 11 houses the laminate cell 10. The housing 11 extends in the second direction. The housing 11 has a cylindrical shape. The shape of the housing 11 is not limited as long as it can house the laminate cell 10. The housing 11 suppresses expansion of the laminate cell 10. The housing 11 is made of, for example, a metal. Examples of metals include aluminum and stainless steel.

[0071] The housing 11 has an opening 111. The opening 111 is located at one end of the housing 11 in the second direction. As shown in Fig. 1A , when the laminate cell 10 is housed in the housing 11, the positive electrode lead 4 and the negative electrode lead 5 extend through the opening 111 to the outside of the housing 11.

[0072] (3) Sealing Body As shown in FIG. 1A , the sealing body 12 is located within the opening 111. The sealing body 12 is adhered to the inner surface of the opening 111. In this way, the sealing body 12 seals the opening 111 of the housing 11. The sealing body 12 is made of a porous body. The porous body is breathable and insulating. Examples of porous bodies include fluororubber sponge and silicone sponge.

[0073] As shown in FIG. 1B , the sealing body 12 has two slits 121A and 121B. The slits 121A and 121B are aligned in a first direction. The slit 121B is positioned away from the slit 121A in the first direction. Each of the slits 121A and 121B extends in the first direction. As shown in FIG. 1A , the positive electrode lead 4 passes through the slit 121A. The negative electrode lead 5 passes through the slit 121B. Note that the slits 121A and 121B may be connected to each other.

[0074] 2. Effects and Advantages (1) According to the battery 1, the sealing body 12 that seals the opening 111 of the housing 11 is made of a porous material that is breathable.

[0075] Therefore, when the battery 1 is used in a vacuum environment, the gas inside the housing 11 passes through the sealing body 12 and is discharged to the outside of the housing 11 .

[0076] As a result, when the battery 1 is used in a vacuum environment, deformation of the housing 11 due to expansion of the gas inside the housing 11 can be suppressed.

[0077] (2) In the battery 1, the housing 11 is made of metal, and the sealing body 12 is made of an insulating porous material.

[0078] Therefore, the rigidity of the housing 11 can suppress expansion of the laminate cell 10 , while the sealing body 12 can insulate the positive electrode lead 4 and the negative electrode lead 5 from the housing 11 .

[0079] (3) According to battery 1, as shown in FIG. 1A , the sealing body has slit 121A through which positive electrode lead 4 passes and slit 121B through which negative electrode lead 5 passes, and is adhered to the inner surface of opening 111.

[0080] Therefore, the battery 1 can be manufactured through a simple process of housing the laminated cell 10 in the housing 11, passing the positive electrode lead 4 through the slit 121A and the negative electrode lead 5 through the slit 121B, inserting the sealing body 12 into the opening 111 of the housing 11, and adhering the sealing body 12 to the inner surface of the opening 111.

[0081] Therefore, the manufacturing efficiency of the battery 1 can be improved.

[0082] The above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and should not be interpreted as being limiting. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the following claims.

[0083] The battery of the present invention can be used as a battery used in a vacuum environment.

[0084] REFERENCE SIGNS LIST 1 Battery 2 Cell 21 Positive electrode layer 22 Negative electrode layer 23 Solid electrolyte layer 3 Current collector 4 Positive electrode lead (an example of a lead) 5 Negative electrode lead (an example of a lead) 6 Laminate film 10 Laminated cell 11 Housing 111 Opening 12 Sealing body 121A Slit 121B Slit

Claims

1. A battery comprising: a laminated cell having leads; a housing having an opening through which the leads pass and containing the laminated cell; and a sealing body made of an air-permeable porous body and sealing the opening of the housing.

2. The battery according to claim 1, wherein the laminate cell comprises: a cell having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer; a current collector laminated on the cell; a laminate film covering the laminate of the cell and the current collector; and the lead connected to the current collector, at least a portion of which is exposed from the laminate film.

3. The battery according to claim 1, wherein the housing is made of metal, and the sealing body is made of the insulating porous body.

4. The battery according to claim 1, wherein the sealing body has a slit through which the lead passes and is adhered to the inner surface of the opening.

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