High safety solid-state battery

Abstract

The utility model discloses a kind of high safety solid-state batteries, its features include composite positive pole piece, solid electrolyte layer and composite negative pole piece, wherein composite positive pole piece includes positive pole piece ontology and first transition layer, the composite negative pole piece includes negative pole piece ontology and second transition layer, solid electrolyte layer is between composite positive pole piece and composite negative pole piece, and with the first transition layer and second transition layer adjacent.In the above scheme, solid electrolyte layer and composite positive pole piece, composite negative pole piece can be assembled into high performance high safety solid-state battery by pressing process, can effectively solve the abnormality of internal short circuit in all-solid-state battery assembly process, while the comprehensive performance of battery is improved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and more specifically to a high-safety solid-state battery. Background Technology

[0002] With the continuous expansion of the electric vehicle and large-scale energy storage equipment markets, higher demands are being placed on the energy density, safety, and cycle life of rechargeable batteries. Traditional batteries use organic electrolytes that are flammable at high temperatures, posing significant safety hazards. Solid-state batteries, which use non-flammable solid electrolytes instead of flammable organic electrolytes, promise high energy density and high safety, and are considered the most promising next-generation batteries. However, during assembly, solid electrolytes exhibit poor flexibility, making the batteries prone to internal short circuits and interface failures during use, ultimately leading to a decline in battery capacity and cycle life.

[0003] To improve battery performance and safety, it is necessary to design a high-safety solid-state battery. Utility Model Content

[0004] This utility model provides a high-safety solid-state battery, characterized by a composite positive electrode, a solid electrolyte layer, and a composite negative electrode. The composite positive electrode includes a positive electrode body and a first transition layer, while the composite negative electrode includes a negative electrode body and a second transition layer. The solid electrolyte layer is located between the composite positive and negative electrodes and is adjacent to both the first and second transition layers. In this solution, the solid electrolyte layer, composite positive electrode, and composite negative electrode can be assembled into a high-performance, high-safety solid-state battery through a pressing process. This effectively solves the problem of internal short circuits in the assembly process of all-solid-state batteries and improves the overall performance of the battery.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This application provides a high-safety solid-state battery;

[0007] Furthermore, the area ratio of the first transition layer to the positive electrode body is ≥1.

[0008] Furthermore, the thickness of the first transition layer is ≤1μm.

[0009] Furthermore, the area ratio of the second transition layer to the negative electrode body is ≥1.

[0010] Furthermore, the thickness of the second transition layer is ≤1μm.

[0011] Furthermore, the first transition layer and the second transition layer are of one or more types selected from polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, and polyethylene oxide.

[0012] Furthermore, the thickness of the solid electrolyte layer is 10-30 μm.

[0013] Furthermore, the solid-state battery is assembled into a battery through a pressing process, with a pressing temperature of ≤100℃ and a pressure of ≤6MPa.

[0014] This application discloses a high-safety solid-state battery, characterized by the use of a lamination process to assemble a solid electrolyte layer, a composite positive electrode, and a composite negative electrode into a battery. During assembly, there is no risk of accidental contact due to improper cutting dimensions of the positive and negative electrodes, puncture of the solid electrolyte by burrs on the edges of the positive and negative electrodes, or rupture of the solid electrolyte leading to an internal short circuit. The first transition layer on the composite positive electrode and the second transition layer on the composite negative electrode can be well integrated with the solid electrolyte layer to form an integrated unit cell through the lamination process, which greatly reduces the risk of internal short circuits in the battery. At the same time, it ensures the interface adhesion between the electrodes and the solid electrolyte layer, reduces the risk of interface failure, and significantly improves the overall performance of the battery. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of solid-state battery assembly. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical applications of the present invention, and to enable those skilled in the art to understand the present invention and design various embodiments with various modifications suitable for a particular purpose.

[0017] Example 1

[0018] Polyvinylidene fluoride (PVDF) is coated onto the surface of the positive electrode 1 to form a first transition layer 2 with a coating thickness of 0.5 μm. The area ratio of the PVDF layer to the positive electrode 1 is 1. PVDF is then coated onto the surface of the negative electrode 5 to form a second transition layer 4 with a coating thickness of 0.3 μm. The area ratio of the PVDF layer to the negative electrode 5 is 1. A solid electrolyte layer 3 with a thickness of 20 μm is selected. The hot press pressing process conditions are set as follows: temperature 60℃, pressure 3 MPa. The composite positive electrode, solid electrolyte layer 3, and composite negative electrode are pressed into a unit sheet structure.

[0019] Comparative Example 1

[0020] A solid electrolyte layer 3 with a thickness of 20μm was selected, and the hot press pressing process conditions were set at 60℃ and 3MPa to press the positive electrode 1, solid electrolyte layer 3, and negative electrode 5 into a unit sheet structure.

[0021] Example 2

[0022] Polymethyl methacrylate (PMMA) is coated onto the surface of the positive electrode 1 to form a first transition layer 2 with a coating thickness of 0.3 μm. The area ratio of the PMMA layer to the positive electrode 1 is 1.05. Polyvinylidene fluoride (PVDF) is coated onto the surface of the negative electrode 5 to form a second transition layer 4 with a coating thickness of 0.3 μm. The area ratio of the PVDF layer to the negative electrode 5 is 1. A solid electrolyte layer 3 with a thickness of 30 μm is selected. The hot press pressing process conditions are set to 70 °C and 4 MPa. The composite positive electrode, solid electrolyte layer 3, and composite negative electrode are pressed into a unit sheet structure.

[0023] Example 3

[0024] Polyacrylonitrile is coated onto the surface of the positive electrode 1 to form a first transition layer 2 with a coating thickness of 0.5 μm and an area ratio of 1.1 between the polyacrylonitrile layer and the positive electrode 1. Polymethyl methacrylate is coated onto the surface of the negative electrode 5 to form a second transition layer 4 with a coating thickness of 0.2 μm and an area ratio of 1.05 between the polymethyl methacrylate layer and the negative electrode 5. A solid electrolyte layer 3 with a thickness of 10 μm is selected. The hot press pressing process conditions are set at 80°C and 5 MPa to press the composite positive electrode, solid electrolyte layer 3, and composite negative electrode into a unit sheet structure.

[0025] Example 4

[0026] Polyvinylidene fluoride (PVDF) is coated onto the surface of the positive electrode 1 to form a first transition layer 2 with a coating thickness of 0.3 μm. The area ratio of the PVDF layer to the positive electrode 1 is 1.05. Polyethylene oxide (PEO) is coated onto the surface of the negative electrode 5 to form a second transition layer 4 with a coating thickness of 0.3 μm. The area ratio of the PEO layer to the negative electrode 5 is 1.05. A solid electrolyte layer 3 with a thickness of 30 μm is selected. The hot press pressing process conditions are set as follows: temperature 50℃, pressure 4 MPa. The composite positive electrode, solid electrolyte layer 3, and composite negative electrode are pressed into a unit sheet structure.

[0027] Example 5

[0028] Polyethylene oxide is coated onto the surface of the positive electrode 1 to form a first transition layer 2 with a coating thickness of 0.9 μm. The area ratio of the polyethylene oxide layer to the positive electrode 1 is 1.05. Polyacrylonitrile is coated onto the surface of the negative electrode 5 to form a second transition layer 4 with a coating thickness of 0.9 μm. The area ratio of the polyacrylonitrile layer to the negative electrode 5 is 1. A solid electrolyte layer 3 with a thickness of 30 μm is selected. The hot press pressing process conditions are set to 100℃ and 6MPa. The composite positive electrode, solid electrolyte layer 3, and composite negative electrode are pressed into a unit sheet structure.

[0029] 100 cells were fabricated according to the above-described embodiments and comparative examples, and the cell short-circuit rate was calculated. The cell short-circuit rate in Comparative Example 1 was 2%, while the cell short-circuit rate in Examples 1-5 was 0%. The test results demonstrate that this application can significantly reduce the risk of internal short circuits in the battery, ensure battery interface adhesion, and improve the overall battery performance.

[0030] Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of this utility model without creative effort should fall within the protection scope of this utility model. Structures, devices, and operating methods not specifically described and explained in this utility model, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A high safety solid-state battery, characterized by, include: A composite positive electrode, a solid electrolyte layer, and a composite negative electrode are provided. The composite positive electrode includes a positive electrode body and a first transition layer. The composite negative electrode includes a negative electrode body and a second transition layer. The solid electrolyte layer is located between the composite positive electrode and the composite negative electrode and is adjacent to the first transition layer and the second transition layer.

2. The solid-state battery as described in claim 1, characterized in that, The area ratio of the first transition layer to the positive electrode body is ≥1.

3. The solid-state battery as described in claim 1, characterized in that, The thickness of the first transition layer is ≤1μm.

4. The solid-state battery as described in claim 1, characterized in that, The area ratio of the second transition layer to the negative electrode body is ≥1.

5. The solid-state battery as described in claim 1, characterized in that, The thickness of the second transition layer is ≤1μm.

6. The solid-state battery as described in claim 1, characterized in that, The thickness of the solid electrolyte layer is 10-30 μm.

7. The solid-state battery as described in claim 1, characterized in that, The solid-state battery is assembled into a battery through a pressing process, with a pressing temperature of ≤100℃ and a pressure of ≤6MPa.

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