JP7603564B2 - Energy Storage Devices - Google Patents

Description

The present invention relates to an electricity storage device.

In view of climate-related disasters, there is a need to reduce _CO2 emissions, and so there is growing interest in electric vehicles equipped with secondary batteries.

Patent Document 1 describes a secondary battery that includes a partition wall that separates the first space and the second space from each other and allows metal ions to pass between the first space and the second space, a negative electrode that is disposed inside the first space and absorbs and releases metal ions, and a positive electrode that is disposed inside the second space and absorbs and releases metal ions. Here, the first space contains a first aqueous electrolyte solution that contains metal ions, and the second space contains a second aqueous electrolyte solution that contains metal ions and has a pH lower than that of the first aqueous electrolyte solution.

International Publication No. 2020/218456

However, the structure of containing the first aqueous electrolyte solution and the second aqueous electrolyte solution in the first space in which the negative electrode is disposed and the second space in which the positive electrode is disposed, respectively, is complex, which increases the time required to manufacture the secondary battery. In addition, during the secondary battery manufacturing process, there is a high possibility that either the first aqueous electrolyte solution or the second aqueous electrolyte solution will be mixed with the other electrolyte solution, which reduces the yield. Furthermore, due to the thermal cycle during charging and discharging of the secondary battery, the partition wall may peel off, which increases the possibility that components contained in either the first space or the second space will be mixed with the other space, which reduces durability.

The present invention aims to provide an electricity storage device that can be manufactured in a shorter time and with improved yield and durability.

In one aspect of the present invention, in an electricity storage device, a positive electrode plate having a positive electrode composite layer formed on both sides of a positive electrode collector, a negative electrode plate having a negative electrode composite layer formed on both sides of a negative electrode collector, and a solid electrolyte layer sandwiched between the positive electrode plate and the negative electrode plate are provided within an exterior body, a joining member is further provided within the exterior body so as to separate a first space in contact with the positive electrode plate and the solid electrolyte layer from a second space in contact with the negative electrode plate and the solid electrolyte layer, a first electrolyte composition is disposed in the first space, and a second electrolyte composition is disposed in the second space.

The first electrolyte composition may be different from the second electrolyte composition.

The above-mentioned power storage device may have a plurality of the positive electrode plates and/or the negative electrode plates and the solid electrolyte layers, and adjacent solid electrolyte layers may be joined via the joining member so that the positive electrode plates do not contact the second space and the negative electrode plates do not contact the first space.

The above-mentioned electric storage device further includes an end member in the exterior body, the end member having a positive electrode composite layer formed on one side of the positive electrode collector and a retaining plate formed on the other side, the solid electrolyte layer is sandwiched between the end member and the negative electrode plate adjacent to the end member, the solid electrolyte layer sandwiched between the end member and the negative electrode plate adjacent to the end member and the retaining plate are joined via the joining member so that the positive electrode collector and the positive electrode composite layer constituting the end member do not come into contact with the second space, and the retaining plate and the exterior body may be joined via the joining member.

The above-mentioned electric storage device further includes an end member in the exterior body, the end member having a negative electrode composite layer formed on one side of the negative electrode collector and a retaining plate formed on the other side, the solid electrolyte layer is sandwiched between the end member and the positive electrode plate adjacent to the end member, the solid electrolyte layer sandwiched between the end member and the positive electrode plate adjacent to the end member and the retaining plate are joined via the joining member so that the negative electrode collector and the negative electrode composite layer constituting the end member do not come into contact with the first space, and the retaining plate and the exterior body may be joined via the joining member.

In the above-mentioned electricity storage device, at least a portion of the region of the solid electrolyte layer that is not in contact with the first space and the second space may be joined to the exterior body via the joining member.

In the above-mentioned power storage device, the joining member may be provided in an area of the solid electrolyte layer that is not sandwiched between the positive electrode plate and the negative electrode plate.

In the above-mentioned power storage device, the positive electrode plate, the negative electrode plate, and the solid electrolyte layer are generally rectangular in plan view, and the areas where the joining members are provided may overlap at least part of two sides of the adjacent solid electrolyte layers other than the sides that are in contact with the first space and the second space.

The present invention provides an energy storage device that can be manufactured in a shorter time and with improved yield and durability.

1 is a cross-sectional view illustrating an example of an electricity storage device according to an embodiment of the present invention. 2 is a cross-sectional view of the electricity storage device of FIG. 1 in the Z-Z' direction. 2A to 2C are diagrams illustrating an example of a method for manufacturing the electricity storage device of FIG. 1 . 2 is a diagram showing a solid electrolyte layer used in a modified example of the electricity storage device in FIG. 1 .

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 shows an example of an electricity storage device according to this embodiment.

The electric storage device 10 includes a positive electrode plate 11 having a positive electrode composite layer 11b formed on both sides of a positive electrode collector 11a, a negative electrode plate 12 having a negative electrode composite layer 12b formed on both sides of a negative electrode collector 12a, and a solid electrolyte layer 13 sandwiched between the positive electrode plate 11 and the negative electrode plate 12, all of which are provided within an exterior body 14. In addition, the electric storage device 10 further includes a joining member 16 provided within the exterior body 14 to separate a first space 15A in contact with the positive electrode plate 11 and the solid electrolyte layer 13 from a second space 15B in contact with the negative electrode plate 12 and the solid electrolyte layer 13. At this time, the positive electrode plate 11 has a positive electrode tab lead 11c extending from the positive electrode collector 11a to the first space 15A side, and the negative electrode plate 12 has a negative electrode tab lead 12c extending from the negative electrode collector 12a to the second space 15B side. Furthermore, in the electricity storage device 10, the first space 15A is filled with a first electrolyte solution as a first electrolyte composition, and the second space 15B is filled with a second electrolyte solution as a second electrolyte composition. This shortens the time required to manufacture the electricity storage device 10. In addition, during the manufacturing process of the electricity storage device 10, the possibility that either the first electrolyte solution or the second electrolyte solution will be mixed with the other electrolyte solution is reduced, improving the yield. Furthermore, due to the thermal cycle during charging and discharging of the electricity storage device 10, the joining member 16 is less likely to peel off, and the components contained in either the first space 15A or the second space 15B are less likely to be mixed into the other space, improving durability.

The exterior body 14 is not particularly limited, but examples thereof include a laminate film.

Examples of materials that can be used to make laminate films include aluminum and stainless steel.

The thickness of the exterior body 14 is not particularly limited, but is, for example, 50 μm or more and 500 μm or less.

The material constituting the joining member 16 is not particularly limited as long as it is capable of joining corresponding members so as to isolate the first space 15A and the second space 15B, but examples include polyolefin resin, epoxy resin, polyurethane resin, acrylic resin, silicone resin, etc.

In the electric storage device 10, an end member 17 having a negative electrode composite layer 17b formed on one side of a negative electrode collector 17a and a holding plate 17c formed on the other side is further provided in the exterior body 14, and a solid electrolyte layer 13 is sandwiched between the end member 17 and a positive electrode plate 11 adjacent to the end member 17. At this time, the end member 17 has a negative electrode tab lead 17d extending from the negative electrode collector 17a to the second space 15B side. In addition, in the electric storage device 10, the solid electrolyte layer 13 sandwiched between the end member 17 and the positive electrode plate 11 adjacent to the end member 17 and the holding plate 17c are joined via a joining member 16 so that the negative electrode collector 17a and the negative electrode composite layer 17b do not come into contact with the first space 15A. In addition, in the electric storage device 10, the holding plate 17c is joined to the exterior body 14 via a joining member 16.

Here, the negative electrode current collector 17a and the negative electrode composite layer 17b may be the same as or different from the negative electrode current collector 12a and the negative electrode composite layer 12b, respectively.

The material constituting the holding plate 17c is not particularly limited as long as it is capable of holding the upper and lower surfaces of the electricity storage device 10 and is chemically stable with respect to the first and second electrolyte solutions, but examples include stainless steel, copper, nickel, polyolefin resin, epoxy resin, polyurethane resin, acrylic resin, silicone resin, etc.

The thickness of the retaining plate 17c is not particularly limited, but is, for example, 100 μm or more and 1000 μm or less.

In place of the end member 17, an end member may be used in which a positive electrode composite layer is formed on one side of a positive electrode collector and a retaining plate is formed on the other side. In this case, a solid electrolyte layer 13 is sandwiched between the end member and the negative electrode plate 12 adjacent to the end member, and the solid electrolyte layer 13 sandwiched between the end member and the negative electrode plate 12 adjacent to the end member and the retaining plate are joined via a joining member 16 so that the positive electrode collector and the positive electrode composite layer constituting the end member do not come into contact with the second space 15B.

In the energy storage device 10, adjacent solid electrolyte layers 13 are joined via joining members 16 so that the positive electrode plate 11 does not contact the second space 15B and the negative electrode plate 12 does not contact the first space 15A. This improves the vibration resistance and volumetric energy density of the energy storage device 10.

As shown in FIG. 2, the energy storage device 10 has an outer casing 14 and an area of the solid electrolyte layer 13 that is not in contact with the first space 15A and the second space 15B joined together via a joining member 16.

3, the electric storage device 10 can be manufactured by welding and joining the outer periphery of the electrode group obtained by stacking the solid electrolyte layer 13, the positive electrode plate 11, the solid electrolyte layer 13, the negative electrode plate 12, etc., which are generally rectangular in plan view, to the exterior body 14 via the joining member 16, and then filling the first space 15A and the second space 15B with the first electrolyte solution and the second electrolyte solution, respectively. At this time, the joining member 16 is provided in the area of the solid electrolyte layer 13 that is not sandwiched between the positive electrode plate 11 and the negative electrode plate 12. Specifically, the solid electrolyte layer 13 on which the positive electrode plate 11 is stacked has the joining member 16 provided on the side on which the positive electrode tab lead 11c extends, that is, on the side on which the positive electrode plate 11 is stacked on the three sides other than the side in contact with the first space 15A. In addition, the solid electrolyte layer 13 on which the negative electrode plate 12 is stacked has a joining member 16 provided on the side where the negative electrode tab lead 12c extends, i.e., on the side on which the negative electrode plate 12 is stacked on three sides other than the side in contact with the second space 15B. Therefore, in the electricity storage device 10, the areas on which the joining members 16 are provided overlap on two sides of the adjacent solid electrolyte layers 13 other than the sides in contact with the first space 15A and the second space 15B.

The width of the joining member 16 provided on the solid electrolyte layer 13 is not particularly limited, but is, for example, 1 mm or more and 10 mm or less.

The solid electrolyte layer 13 on which the positive electrode plate 11 is laminated may have a bonding member 16 on the side on which the positive electrode plate 11 is not laminated, and the solid electrolyte layer 13 on which the negative electrode plate 12 is laminated may have a bonding member 16 on the side on which the negative electrode plate 12 is not laminated.

In addition, as shown in FIG. 4, the electric storage device 10 may have overlapping areas in which the joining members 16 are provided on parts of two sides other than the sides in contact with the first space 15A and the second space 15B of the adjacent solid electrolyte layer 13.

The length L of the overlap between the regions where the joining members 16 of adjacent solid electrolyte layers 13 are provided is preferably 5 mm or more, and more preferably 10 mm or more. When L is 5 mm or more, the yield and durability of the electricity storage device 10 are improved.

The energy storage device 10 has two positive electrode plates 11, one negative electrode plate 12, and four solid electrolyte layers 13, but the numbers of the positive electrode plates 11, negative electrode plates 12, and solid electrolyte layers 13 are not particularly limited.

In addition, when the energy storage device 10 has multiple positive electrode plates 11, negative electrode plates 12, and solid electrolyte layers 13, the multiple positive electrode plates 11, negative electrode plates 12, and solid electrolyte layers 13 may be the same or different.

The energy storage device 10 is not particularly limited as long as it is a device capable of repeatedly storing and releasing electrical energy, but examples include a lithium ion secondary battery, a lithium air battery, a lithium ion capacitor, a redox flow battery, etc.

The following describes the case where the power storage device 10 is a lithium ion secondary battery.

The positive electrode collector 11a is not particularly limited, but examples thereof include metal foil such as aluminum foil.

The thickness of the positive electrode collector 11a is not particularly limited, but is, for example, 5 μm or more and 15 μm or less.

The positive electrode composite layer 11b contains a positive electrode active material, and may further contain a solid electrolyte, a conductive additive, a binder, etc., as necessary.

The positive electrode active material is not particularly limited as long as it is capable of absorbing and releasing lithium ions, and examples thereof include _LiCoO2 , Li(Ni5 _/10Co2 / _10Mn3 / ₁₀ ) _O2, Li(Ni6/10Co2/ _10Mn2 / ₁₀ )O2 _, Li(Ni8/10Co1/ _10Mn1 / ₁₀ )O2 _, Li( _{Ni0.8Co0.15Al0.05} ) _{O2 ,} Li( _Ni1 / _6Co4 / _6Mn1 / ₆ ) _{O2 , Li} (Ni1/ _{3Co1 /3Mn1} / ₃ ) _{O2 ,} LiCoO4, and _{LiMn2O4 .} , LiNiO ₂ , LiFePO ₄ , lithium sulfide, sulfur, etc. These positive electrode active materials may be used alone or in combination.

The content of the positive electrode active material in the positive electrode composite layer 11b is not particularly limited, but is, for example, 75% by mass or more and 95% by mass or less.

The thickness of the positive electrode composite layer 11b is not particularly limited, but is, for example, 20 μm or more and 1000 μm or less.

The negative electrode current collector 12a is not particularly limited, but examples thereof include metal foil such as copper foil.

The thickness of the negative electrode collector 12a is not particularly limited, but is, for example, 5 μm or more and 15 μm or less.

The negative electrode composite layer 12b contains a negative electrode active material, and may further contain a solid electrolyte, a conductive additive, a binder, etc., as necessary.

The content of the negative electrode active material in the negative electrode composite layer 12b is not particularly limited, but is, for example, 60% by mass or more and 95% by mass or less.

The negative electrode active material is not particularly limited as long as it is capable of absorbing and releasing lithium ions, but examples include metallic lithium, lithium alloys, metal oxides, metal sulfides, metal nitrides, Si, SiO, carbon materials, etc. These negative electrode active materials may be used alone or in combination.

Examples of carbon materials include artificial graphite, natural graphite, hard carbon, soft carbon, etc.

The thickness of the negative electrode composite layer 12b is not particularly limited, but is, for example, 10 μm or more and 500 μm or less.

The solid electrolyte constituting the solid electrolyte layer 13 is not particularly limited, but examples thereof include lithium ion conductive oxides and lithium ion conductive sulfides.

The thickness of the solid electrolyte layer 13 is not particularly limited, but is, for example, 20 μm or more and 150 μm or less.

The first electrolyte and the second electrolyte may be the same or different.

When the first electrolyte solution and the second electrolyte solution are different, an aqueous electrolyte solution and a non-aqueous electrolyte solution (organic electrolyte solution) can be used as the first electrolyte solution and the second electrolyte solution, respectively.

Aqueous electrolytes contain an electrolyte and water.

Examples of electrolytes contained in the aqueous electrolyte include lithium chloride, lithium sulfate, lithium acetate, and lithium perchlorate. These electrolytes may be used alone or in combination.

The non-aqueous electrolyte contains an electrolyte and an organic solvent.

Examples of electrolytes contained in the non-aqueous electrolyte include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium bisfluorosulfonylimide, and lithium bistrifluoromethanesulfonylimide. These electrolytes may be used alone or in combination.

Examples of organic solvents contained in the non-aqueous electrolyte include propylene carbonate, ethylene carbonate, diethyl carbonate, ethyl methyl carbonate, and diethylene glycol dimethyl ether. These organic solvents may be used alone or in combination.

In addition, a polymer gel electrolyte may be prepared by adding a polymer gelling agent to at least one of the first electrolytic solution and the second electrolytic solution. In other words, at least one of the first electrolytic solution and the second electrolytic solution may be prepared as a polymer gel electrolyte having a polymer gelling agent as a matrix.

In addition, instead of filling the first space 15A with a first electrolytic solution, a solid electrolyte having a similar function to the first electrolytic solution may be placed, and instead of filling the second space 15B with a second electrolytic solution, a solid electrolyte having a similar function to the second electrolytic solution may be placed. These solid electrolytes may be placed in the first space 15A or the second space 15B, or may be placed in the first space 15A and the second space 15B.

The solid electrolyte is not particularly limited, but examples thereof include lithium ion conductive oxides and lithium ion conductive sulfides.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the above embodiments may be modified as appropriate within the scope of the spirit of the present invention.

REFERENCE SIGNS LIST 10 Electricity storage device 11 Positive electrode plate 11a Positive electrode current collector 11b Positive electrode composite layer 11c Positive electrode tab lead 12 Negative electrode plate 12a Negative electrode current collector 12b Negative electrode composite layer 12c Negative electrode tab lead 13 Solid electrolyte layer 14 Exterior body 15A First space 15B Second space 16 Joining member 17 End member 17a Negative electrode current collector 17b Negative electrode composite layer 17c Holding plate 17d Negative electrode tab lead

Claims (8)

a positive electrode plate having a positive electrode mixture layer formed on both sides of a positive electrode current collector, a negative electrode plate having a negative electrode mixture layer formed on both sides of a negative electrode current collector, and a solid electrolyte layer sandwiched between the positive electrode plate and the negative electrode plate,
a bonding member is further provided in the exterior body so as to separate a first space in contact with the positive electrode plate and the solid electrolyte layer from a second space in contact with the negative electrode plate and the solid electrolyte layer;
a first electrolyte composition is disposed in the first space;
A second electrolyte composition is disposed in the second space. The power storage device according to claim 1, wherein the first electrolyte composition is different from the second electrolyte composition. The battery includes a plurality of positive and negative electrode plates and a plurality of solid electrolyte layers,
3. The electricity storage device according to claim 1, wherein adjacent solid electrolyte layers are joined via the joining member such that the positive electrode plate does not contact the second space and the negative electrode plate does not contact the first space. an end member having a positive electrode mixture layer formed on one surface of a positive electrode current collector and a holding plate formed on the other surface of the end member is further provided within the exterior body;
the solid electrolyte layer is sandwiched between the end member and the negative electrode plate adjacent to the end member,
a solid electrolyte layer sandwiched between the end member and the negative electrode plate adjacent to the end member and the retaining plate are joined via the joining member so that the positive electrode current collector and the positive electrode mixture layer constituting the end member do not come into contact with the second space,
The power storage device according to claim 3 , wherein the holding plate and the exterior body are joined via the joining member. an end member having a negative electrode mixture layer formed on one surface of a negative electrode current collector and a holding plate formed on the other surface of the end member is further provided within the exterior body;
the solid electrolyte layer is sandwiched between the end member and the positive electrode plate adjacent to the end member,
a solid electrolyte layer sandwiched between the end member and the positive electrode plate adjacent to the end member and the retaining plate are joined via the joining member so that the negative electrode current collector and the negative electrode mixture layer constituting the end member do not come into contact with the first space,
The power storage device according to claim 3 , wherein the holding plate and the exterior body are joined via the joining member. The electric storage device according to any one of claims 3 to 5, wherein at least a portion of the region of the solid electrolyte layer that is not in contact with the first space and the second space is joined to the exterior body via the joining member. The electric storage device according to any one of claims 3 to 6, wherein the joining member is provided in an area of the solid electrolyte layer that is not sandwiched between the positive electrode plate and the negative electrode plate. the positive electrode plate, the negative electrode plate, and the solid electrolyte layer are generally rectangular in plan view,
8. The power storage device according to claim 7, wherein adjacent two sides of the solid electrolyte layer other than the sides in contact with the first space and the second space have overlapping regions in which the joining members are provided.

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