Battery cell unit and solid-state battery

Abstract

The utility model relates to the technical field of lithium batteries. The utility model provides a battery cell unit and a solid-state battery. The battery cell unit comprises a positive electrode, a lithium-free negative electrode and a solid-state electrolyte layer arranged between the positive electrode and the lithium-free negative electrode, the positive electrode comprises a positive electrode current collector and a positive electrode active material layer arranged on the positive electrode current collector; the lithium-free negative electrode comprises a negative electrode current collector; and an elastic buffer layer is arranged on one side, far away from the solid electrolyte layer, of the negative current collector. The lithium-free negative electrode is used, the function of the battery can be realized without arranging an active material layer on the negative electrode current collector, and the energy density of the battery can be improved. And the elastic buffer layer is also arranged in the lithium-free negative electrode, so that the influence of the volume change of the lithium-free negative electrode on the battery in the deposition and stripping process of lithium ions is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery technical field, especially a kind of battery cell unit and solid-state battery. BACKGROUND

[0002] With the development and progress of science and technology, lithium ion battery is increasingly widely used in power, energy storage, 3C and other fields, and the market requires higher and higher energy density of lithium ion battery.

[0003] Generally, in lithium ion solid-state battery, the thinner the current collector material of negative electrode is, the more the energy density of battery is improved, but limited by safety and other issues, the current collector material of negative electrode cannot be thinned continuously after reaching a certain threshold, which also leads to the energy density of lithium ion solid-state battery cannot be improved continuously.

[0004] To solve the above problems, the utility model provides a new lithium ion solid-state battery and battery cell unit, by adopting lithium-free negative electrode, without setting active material layer technical scheme, on the basis of realizing battery charge and discharge, the energy density of battery is significantly improved, and in order to reduce the bad influence of the volume change of battery during battery discharge, the utility model also sets up elastic buffer layer for reducing the above change. UTILITY MODEL CONTENT

[0005] To solve the above problems, the utility model provides a kind of battery cell unit and solid-state battery.The technical scheme of the utility model is as follows:

[0006] The first aspect of the utility model is to propose a battery cell unit.The battery cell unit includes a positive electrode, a lithium-free negative electrode and a solid-state electrolyte layer arranged between the positive electrode and the lithium-free negative electrode;The positive electrode includes a positive electrode current collector and a positive electrode active material layer arranged on the positive electrode current collector;

[0007] The lithium-free negative electrode includes a negative electrode current collector;

[0008] The side of the negative electrode current collector away from the solid-state electrolyte layer is provided with an elastic buffer layer.

[0009] The utility model uses lithium-free negative electrode, and the negative electrode current collector does not need to set active material layer to realize battery function, under the same battery thickness, more battery cell units can be accommodated, and the energy density of battery can be greatly improved.The utility model also sets up elastic buffer layer, reduces the influence of volume change of lithium-free negative electrode on battery during deposition and stripping process of lithium ion.

[0010] Preferably, the positive electrode active material layer is arranged on both sides of the positive electrode current collector, wherein the thickness of the positive electrode active material layer on one side is 10 μm-100 μm.

[0011] Preferably, the solid-state electrolyte layer comprises a first solid-state electrolyte layer and a second solid-state electrolyte layer arranged in a stack.

[0012] Preferably, the first solid-state electrolyte layer is arranged between the positive electrode active material layer and the negative current collector, and the thickness of the first solid-state electrolyte layer is 5-50 μm.

[0013] Preferably, the second solid-state electrolyte layer is arranged between the first solid-state electrolyte layer and the negative current collector, and the thickness of the second solid-state electrolyte layer is 2-20 μm.

[0014] Preferably, the first solid-state electrolyte layer and / or the second solid-state electrolyte layer comprises a polymer solid-state electrolyte layer.

[0015] Preferably, the elastic buffer layer comprises at least one of a foam layer and an aerogel layer.

[0016] Preferably, the thickness of the elastic buffer layer is 20-200 μm.

[0017] Preferably, the foam layer is selected from a stack of any one or more of a polyurethane layer, a foamed polyethylene layer, a foamed polystyrene layer, a foamed ethylene-propylene-diene rubber layer, a chloroprene rubber layer, a synthetic foamed polybutadiene rubber layer, a foamed thermoplastic polyurethane layer, an ethylene-vinyl acetate copolymer layer, a chemically cross-linked polyethylene foam layer, a nitrile rubber layer, a styrene-butadiene rubber layer, an electron radiation cross-linked polyethylene foam layer, and an electron radiation cross-linked polypropylene foam layer.

[0018] Preferably, the aerogel layer is selected from a stack of any one or more of a silicon dioxide aerogel layer, a titanium dioxide aerogel layer, a zirconium oxide aerogel layer, an aluminum oxide aerogel layer, a tungsten oxide aerogel layer, a silicon carbide aerogel layer, and a graphene aerogel layer.

[0019] A second aspect of the utility model provides a solid-state battery.

[0020] The utility model discloses a lithium-free negative electrode, when the solid-state battery is charged, lithium ions move from the positive electrode to the negative electrode, and the lithium ions are deposited on the negative electrode current collector at the contact interface between the negative electrode current collector and the solid-state electrolyte layer, and when the solid-state battery is discharged, the lithium deposited on the negative electrode current collector is stripped, the above process enables the negative electrode current collector to realize the function of the battery without an active material layer, and improves the energy density of the battery, however, in the above process, the deposition and stripping of lithium ions change the volume of the battery, therefore, the elastic buffer layer is arranged in the application to reduce the influence of the volume change of the lithium ion battery in the above process. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] Wherein the same parts are indicated by the same reference numerals. It should be noted that the words "front", "back", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "bottom" and "top", "inner" and "outer" refer to the directions towards or away from the geometric center of a particular part.

[0023] Figure 1 Structure diagram of solid-state battery in the embodiment of the present application;

[0024] Figure 2 Structure diagram of the battery cell unit in the embodiment of the present application. It should be noted that, Figure 1 The solid-state battery shown in the figure includes two battery cell units, and the two battery cell units share an elastic buffer layer. In order to distinguish a single battery cell unit, Figure 2 The position of the elastic buffer layer is not shown in the figure.

[0025] In the above drawings, each figure number mark represents:

[0026] 1. Negative current collector;

[0027] 2. Second solid-state electrolyte layer;

[0028] 3. First solid-state electrolyte layer;

[0029] 4. Positive active material layer;

[0030] 5. Positive current collector;

[0031] 6. Elastic buffer layer. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the summary of the application and the detailed description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the use of the terms "including" and "having" and variations thereof herein is meant to encompass the inclusion of but not limited to.

[0034] In the description of the specific embodiments of the application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0035] In the present application, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it independent or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0036] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents a "or" relationship between the front and rear associated objects.

[0037] Throughout this utility, numerical values represent approximate measurements or limits to encompass minor deviations from given values and embodiments having about the referenced values and embodiments having the referenced exact values. Except in the Examples provided at the end of the DETAILED DESCRIPTION, all numerical values of parameters (e.g., amounts or conditions) in this specification, including the attached claims, are to be interpreted as being modified in all instances by the term "about" whether or not "about" actually appears before the numerical value. "About" indicates that the value presented is a close approximation to the exact value. If the inexactness is not otherwise apparent from the context, then the inexactness is understood to be within a range of values that one of ordinary skill in the art would consider to be about the value presented. For example, "about" can include a variation less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects, optionally less than or equal to 0.1%.

[0038] In addition, the disclosure of ranges includes all values and further divisions of ranges within the entire ranges, including the endpoints and subranges given for the ranges.

[0039] The first aspect of the utility is to propose an electric core unit, the electric core unit includes a positive electrode, a lithium-free negative electrode and a solid electrolyte layer arranged between the positive electrode and the lithium-free negative electrode;The positive electrode includes a positive electrode current collector and a positive electrode active material layer arranged on the positive electrode current collector;The lithium-free negative electrode includes a negative electrode current collector;The negative electrode current collector is provided with an elastic buffer layer on the side away from the solid electrolyte layer.

[0040] The utility adopts a lithium-free negative electrode, when the solid-state battery is charged, lithium ions move from the positive electrode to the negative electrode, and the lithium ions are deposited on the negative electrode current collector at the contact interface between the negative electrode current collector and the solid electrolyte layer, and when the solid-state battery is discharged, the lithium deposited on the negative electrode current collector will be stripped, the above process enables the negative electrode current collector to realize the function of the battery without setting the active material layer, and can improve the energy density of the battery, however, in the above process, the deposition and stripping of lithium ions will change the volume of the battery, therefore, the elastic buffer layer is also arranged in the application to reduce the influence of the volume change of the lithium ion battery in the above process.

[0041] The utility sets the elastic buffer layer at the negative electrode current collector instead of the positive electrode current collector, because the positive electrode active material layer is arranged on both sides of the positive electrode current collector, and the negative electrode active material layer is not arranged at the negative electrode current collector, therefore, setting at the negative electrode can reduce the influence on the energy density of the battery.

[0042] The utility model discloses, only need to set up the elastic buffer layer at the negative current collector, and the elastic buffer layer can be individually arranged at the negative current collector of each battery cell unit, also can be commonly arranged between the negative current collector of adjacent battery cell units, so that adjacent battery cell units can share this elastic buffer layer, and the setting mode of the above elastic buffer layer is only an example, and is not limited.

[0043] In some embodiments, the positive active material layer is disposed on both sides of the positive current collector, wherein the thickness of the single-sided active material layer is 10-100 μm.

[0044] In practical applications, the thickness of the single-sided active material layer can be specifically selected as 10 μm, 15 μm, 18 μm, 20 μm, 25 μm, 28 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm. The above values are only examples and are not limited.

[0045] In some embodiments, the solid-state electrolyte layer comprises a first solid-state electrolyte layer and a second solid-state electrolyte layer arranged in layers.

[0046] The utility model uses the solid-state electrolyte layer instead of the traditional electrolyte and diaphragm, improves the safety of the battery, and at the same time improves the moving speed of lithium ions and increases the energy density of the battery.

[0047] In some embodiments, the first solid-state electrolyte layer is disposed between the positive active material layer and the negative current collector, and the thickness of the first solid-state electrolyte layer is 5-50 μm. In practical applications, the thickness of the first solid-state electrolyte layer can be specifically selected as 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm. The above values are only examples and are not limited.

[0048] In some embodiments, the second solid-state electrolyte layer is disposed between the first solid-state electrolyte layer and the negative current collector, and the thickness of the second solid-state electrolyte layer is 2-20 μm.

[0049] In practical applications, the thickness of the second solid-state electrolyte layer can be specifically selected as 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm. The above values are only examples and are not limited.

[0050] The solid electrolytes in the first solid electrolyte layer and the second solid electrolyte layer may include, but are not limited to, one or more of halide solid electrolytes, sulfide solid electrolytes, and oxide solid electrolytes.

[0051] The halide solid electrolyte may be selected from: Li2CdC 1.65 , 0.5 , 10 , 2.19 , 12 , 0.75 , 12 , 12 , 12 , 12 , 12 , 10 , 0.5 , 0.5 , 10.35 , 10 , 0.5 , 12 , 9.81 , 3.25 , 0.5 , 0.5 , 1.35 , 0.81 , 12 , 0.25 、Li2MgC l4 、Li2Cd I4 、Li2ZnI4, Li3OCl, LiI, Li5ZnI4, Li3OCl 1-x Br x (where 0 < x < 1) and combinations thereof.

[0052] The sulfide solid electrolyte may be selected from: Li2S-P2S5, Li2S-P2S5-MS x (where M is Si, Ge, or Sn and 0 ≤ x ≤ 2), Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 、Li 9.6 P3S 12 、Li7P3S 11 、Li9P3S9O3, Li 10.35 Si 1.35 P 1.65 S 12 、Li 9.81 Sn 0.81 P 2.19 S 12 、Li 10 (Si 0.5 Ge 0.5 )P2S 12 、Li(Ge 0.5 Sn 0.5 )P2S 12 、Li(Si 0.5 Sn 0.5 )PsS 12 、Li 10 GeP2S 12 (LGPS), Li6PS5X (where X is Cl, Br, or I), Li7P2S8I, Li 10.35 Ge 1.35 P 1.65 S 12 、Li 3.25 Ge 0.25 P 0.75 S4, Li 10 SnP2S 12 、Li10 SiP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 , (1-x) P2S 5-x Li₂S (where 0.5 ≤ x ≤ 0.7) and their combinations.

[0053] Oxide solid electrolytes include: perovskite type, garnet type, LISICON type, and NASICON type. Among them, the preferred perovskite type solid electrolyte material is LLTO (lithium lanthanum titanium oxide / lithium lanthanum titanate, Li...). 0.33 La 0.56 TiO3), the preferred garnet-type solid electrolyte material is LLZO (lithium lanthanum zirconium oxide / lithium lanthanum zirconate, Li7La3Zr2O). 12 The preferred solid electrolyte material is NASICON (sodium superionic conductor) type lithium titanium aluminum phosphate LATP (Li 1.3 Al 0.3 Ti 1.7 (PO4)3). The above examples are for illustrative purposes only and are not intended to be limiting.

[0054] In this invention, the first solid electrolyte layer and / or the second solid electrolyte layer comprises a polymer solid electrolyte layer, wherein the polymer solid electrolyte layer can increase the adhesion between the polymer solid electrolyte layer and the active material layer and the current collector. The polymer solid electrolyte layer may be disposed in the first solid electrolyte layer, may be disposed in the second solid electrolyte layer, or may both the first and second solid electrolyte layers contain polymer solid electrolytes.

[0055] The polymer solid electrolyte can be selected from one or more of polyacrylic acid (PAA), PEO (polyoxyethylene), PAN (polyacrylonitrile), PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), and PPC (polymethyl methacrylate).

[0056] In some embodiments, the elastic buffer layer includes at least one of a foam layer and an aerogel layer.

[0057] The elastic buffer layer can be a single-layer foam layer, a multi-layer foam layer, a single-layer aerogel layer, a multi-layer aerogel layer, or a combination of foam and aerogel layers, etc. The above are just examples and are not limitations.

[0058] In some embodiments, the thickness of the elastic buffer layer is 20 μm-200 μm.

[0059] In specific applications, the thickness of the elastic buffer layer can be selected from 20μm, 50μm, 80μm, 100μm, 120μm, 140μm, 150μm, 180μm, and 200μm. The above values ​​are for illustrative purposes only and are not intended to be limiting.

[0060] In some embodiments, the foam layer is a laminate; the foam layer is selected from at least one of the following: polyurethane layer, foamed polyethylene layer, foamed polystyrene layer, foamed EPDM rubber layer, chloroprene rubber layer, synthetic foamed polybutadiene rubber layer, foamed thermoplastic polyurethane layer, ethylene-vinyl acetate copolymer layer, chemically cross-linked polyethylene foam material layer, nitrile rubber layer, styrene-butadiene rubber layer, electron radiation cross-linked polyethylene foam material layer, and electron radiation cross-linked polypropylene foam material layer.

[0061] In some embodiments, the aerogel layer is a laminate; the aerogel layer is selected from at least one of silica aerogel layer, titanium dioxide aerogel layer, zirconium oxide aerogel layer, alumina aerogel layer, tungsten oxide aerogel layer, silicon carbide aerogel layer, and graphene aerogel layer.

[0062] The second aspect of this invention is to provide a solid-state battery comprising a plurality of stacked battery cell units.

[0063] The embodiments of this utility model will be described in more detail below through examples. It should be noted that the embodiments of this utility model are not limited to these examples.

[0064] Example

[0065] In one specific embodiment, such as Figure 1 As shown, a solid-state battery includes two stacked batteries as shown. Figure 2 The battery cell unit shown is as follows. Each battery cell unit includes: two negative current collectors 1, two second solid electrolyte layers 2, two first solid electrolyte layers 3, two positive active material layers 4, and one positive current collector 5.

[0066] Two positive electrode active material layers 4 are respectively attached to the upper and lower surfaces of the positive electrode current collector 5. Two first solid electrolyte layers 3 are respectively attached to the surfaces of the two positive electrode active material layers 4 away from the positive electrode current collector 5. Two second solid electrolyte layers 2 are respectively attached to the surfaces of the two first solid electrolyte layers 3 away from the positive electrode active material layers 4. Two negative electrode current collectors 1 are respectively attached to the surfaces of the two second solid electrolyte layers 2 away from the first solid electrolyte layers 3.

[0067] It should be noted that in this embodiment, because two battery cell units share a single elastic buffer layer 6, therefore... Figure 2 The elastic buffer layer 6 is not shown in the figure. The elastic buffer layer 6 is as follows:Figure 1 The elastic buffer layer 6 is shown in the middle between two battery cell units. However, it is known to those skilled in the art that the elastic buffer layer 6 can also be provided alone at the negative current collector of each battery cell unit.

[0068] It should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electric cell unit, characterized by comprising: Comprising: a positive electrode, a lithium-free negative electrode, and a solid electrolyte layer disposed between the positive electrode and the lithium-free negative electrode; the positive electrode comprises a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector; the lithium-free negative electrode comprises a negative electrode current collector; the negative electrode current collector is provided with an elastic buffer layer on the side away from the solid electrolyte layer.

2. The cell unit of claim 1, wherein, the positive electrode active material layer is disposed on both sides of the positive electrode current collector, wherein the thickness of the positive electrode active material layer on one side is 10-100 μm.

3. The cell unit of claim 1, wherein, the solid electrolyte layer comprises a first solid electrolyte layer and a second solid electrolyte layer stacked.

4. The cell unit of claim 3, wherein, the first solid electrolyte layer is disposed between the positive electrode active material layer and the negative electrode current collector, and the thickness of the first solid electrolyte layer is 5-50 μm.

5. The cell unit of claim 3, wherein, the second solid electrolyte layer is disposed between the first solid electrolyte layer and the negative electrode current collector, and the thickness of the second solid electrolyte layer is 2-20 μm.

6. The cell unit of claim 5, wherein, the first solid electrolyte layer and / or the second solid electrolyte layer comprises a polymer solid electrolyte layer.

7. The cell unit of claim 1, wherein, the elastic buffer layer comprises at least one of a foam layer and an aerogel layer, and the thickness of the elastic buffer layer is 20-200 μm.

8. The cell unit of claim 7, wherein, the foam layer is selected from a stack of any one or more of a polyurethane layer, a foamed polyethylene layer, a foamed polystyrene layer, a foamed ethylene-propylene-diene rubber layer, a chloroprene rubber layer, a synthetic foamed polybutadiene rubber layer, a foamed thermoplastic polyurethane layer, an ethylene-vinyl acetate copolymer layer, a chemically cross-linked polyethylene foam material layer, a nitrile rubber layer, a styrene-butadiene rubber layer, an electron radiation cross-linked polyethylene foam material layer, and an electron radiation cross-linked polypropylene foam material layer.

9. The cell unit of claim 7, wherein, the aerogel layer is selected from a stack of any one or more of a silica aerogel layer, a titanium dioxide aerogel layer, a zirconium oxide aerogel layer, an aluminum oxide aerogel layer, a tungsten oxide aerogel layer, a silicon carbide aerogel layer, and a graphene aerogel layer.

10. A solid-state battery comprising a plurality of the cell units of any one of claims 1-9 stacked.

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