Solid state battery

Abstract

The utility model relates to the technical field of solid-state batteries, and discloses a solid-state battery. The solid-state battery comprises a positive plate and a negative plate which are sequentially stacked, a solid-state electrolyte layer is further arranged between the positive plate and the negative plate, at least one side edge of the negative plate is arranged to exceed the positive plate, and the exceeding distance is set to be b; the solid-state battery further comprises a supporting piece, the supporting piece is arranged on the outer side of the positive plate and corresponds to the position, exceeding the positive plate, of the negative plate, the thickness of the supporting piece in the direction perpendicular to the positive plate is h1, the thickness of the positive plate is h2, h1 / h2 is 0.6-1, the width of the supporting piece in the direction, exceeding the positive plate, of the negative plate is a, and a / b is 0.5-1. According to the utility model, the solid-state electrolyte layers on the two sides of the positive plate can be effectively supported, the condition that the solid-state electrolyte layers are broken in the pressing process is avoided, and the safety and the reliability of the solid-state battery are improved.

Description

Technical Field

[0001] This utility model relates to the field of solid-state battery technology, and in particular to solid-state batteries. Background Technology

[0002] All-solid-state batteries use solid electrolytes. Because they use solid electrolytes instead of liquid organic electrolytes, their safety performance is greatly improved. The assembly process of all-solid-state batteries requires high pressure, typically using isostatic presses or thermostatic presses, with pressure ranges from 200 MPa to 1000 MPa.

[0003] Because all-solid-state batteries use traditional electrodes with extremely large negative and extremely small positive electrodes, an overhang region is formed around the positive electrode. This overhang region in solid-state batteries is prone to short circuits because there is no separator winding; the positive and negative electrodes are stacked on top of each other without an insulating layer for protection. Furthermore, solid-state batteries require significant pressure during assembly, and under this high pressure, the shear force between the electrodes can easily cause the solid electrolyte layer to rupture, leading to a short circuit.

[0004] Therefore, there is an urgent need for a solid-state battery to solve the above problems. Summary of the Invention

[0005] Based on the above, the purpose of this utility model is to provide a solid-state battery that can effectively support the solid electrolyte layers on both sides of the positive electrode, avoid the solid electrolyte layers from cracking during the pressing process, and improve the safety and reliability of the solid-state battery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A solid-state battery includes a positive electrode and a negative electrode stacked sequentially, a solid electrolyte layer is disposed between the positive electrode and the negative electrode, and at least one edge of the negative electrode extends beyond the positive electrode by a distance b.

[0008] The solid-state battery also includes a support member disposed outside the positive electrode and corresponding to the position where the negative electrode extends beyond the positive electrode. The thickness of the support member along the direction perpendicular to the positive electrode is set to h1, the thickness of the positive electrode is set to h2, and h1 / h2 is set to 0.6-1. The width of the support member along the direction where the negative electrode extends beyond the positive electrode is a, and a / b is set to 0.5-1.

[0009] The beneficial effects of this utility model are as follows:

[0010] Solid-state batteries consist of positive and negative electrode sheets stacked sequentially, with a solid electrolyte layer between them. At least one side of the negative electrode sheet extends beyond the positive electrode sheet. This extra-large size of the negative electrode sheet prevents lithium ions extracted from the positive electrode from reaching the negative electrode and causing lithium plating due to insufficient intercalation sites. Since solid-state battery fabrication requires pressing, a support structure is included to prevent the solid electrolyte layer from cracking under shear forces during pressing. This support structure is positioned outside the positive electrode sheet, corresponding to the position where the negative electrode sheet extends beyond the positive electrode sheet. The thickness of the support structure is 0.6-1 times the thickness of the positive electrode sheet, and the width of the support structure is 0.5-1 times the width of the negative electrode sheet extending beyond the positive electrode sheet. It can be understood that the thickness of the support structure is the thickness perpendicular to the positive electrode sheet, and the width of the support structure is the width of the support structure along the direction where the negative electrode sheet extends beyond the positive electrode sheet. If these thickness ratios are too small, the intended support effect will not be achieved; if they are too large, the solid electrolyte layer and the negative electrode sheet will be damaged. If the aforementioned width ratio is too small, the solid electrolyte layer may bend or break during the pressing process, causing a short circuit between the positive and negative electrodes. If the ratio is too large, the support will extend beyond the edge of the solid electrolyte layer and the negative electrode, taking up extra space. If the support is folded to the back side of the negative electrode, it will also cause poor contact between the negative electrode and the adjacent positive electrode, thus affecting the normal use of the solid-state battery. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram showing the relationship between the positive electrode, the negative electrode, and the solid electrolyte layer.

[0013] Figure 2 This is a partially exploded schematic diagram of a solid-state battery provided in a specific embodiment of this utility model;

[0014] Figure 3 This is a partial schematic diagram of a solid-state battery provided in a specific embodiment of this utility model.

[0015] In the picture:

[0016] 110. Positive electrode plate; 111. Positive electrode tab; 112. Positive electrode current collector; 113. Positive electrode active material layer; 120. Negative electrode plate; 130. Solid electrolyte layer;

[0017] 200. Support components;

[0018] 300. Adhesive layer. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0021] Unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and connections within two components or interactions between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 and Figure 2As shown, this embodiment provides a solid-state battery, which includes a positive electrode 110 and a negative electrode 120 stacked sequentially. A solid electrolyte layer 130 is also disposed between the positive electrode 110 and the negative electrode 120, and at least one edge of the negative electrode 120 extends beyond the positive electrode 110 by a distance b. The solid-state battery also includes a support member 200, which is disposed outside the positive electrode 110 and is disposed corresponding to the position where the negative electrode 120 extends beyond the positive electrode 110. The thickness of the support member 200 along the direction perpendicular to the positive electrode 110 is h1, the thickness of the positive electrode 110 is h2, and the ratio of h1 to h2 is 0.6-1. The width of the support member 200 along the direction where the negative electrode 120 extends beyond the positive electrode 110 is a, and the ratio of a to b is 0.5-1.

[0025] The solid-state battery includes a positive electrode 110 and a negative electrode 120 stacked sequentially, with a solid electrolyte layer 130 disposed between the positive electrode 110 and the negative electrode 120. At least one side of the negative electrode 120 extends beyond the positive electrode 110. This ensures that the size of the negative electrode 120 exceeds the size of the positive electrode 110, preventing lithium ions extracted from the positive electrode from reaching the negative electrode and thus avoiding lithium plating due to insufficient intercalation sites. Since the solid-state battery manufacturing process requires pressing, a support member 200 is also provided to prevent the solid electrolyte layer 130 from cracking under shear force during pressing. The support member 200 is disposed outside the positive electrode 110, corresponding to the position where the negative electrode 120 extends beyond the positive electrode 110. The thickness of the support member 200 is 0.6-1 times the thickness of the positive electrode 110, and the width of the support member 200 is 0.5-1 times the width of the negative electrode 120 extending beyond the positive electrode 110. If the aforementioned thickness ratio is too small, it will not provide the intended support effect; if it is too large, it will damage the solid electrolyte layer 130 and the negative electrode 120. If the aforementioned width ratio is too small, the portion of the solid electrolyte layer 130 extending beyond the positive electrode 110 may bend or break during the pressing process, resulting in a short circuit between the positive and negative electrodes. If the ratio is too large, the support member 200 will extend beyond the edges of the solid electrolyte layer 130 and the negative electrode 120, occupying additional space. If the support member 200 is folded to the back side of the negative electrode 120, it will also cause poor contact between the negative electrode 120 and the adjacent positive electrode 110, thus affecting the normal use of the solid-state battery.

[0026] It is understandable that the thickness of the support member 200 is the thickness of the support member 200 along the direction perpendicular to the positive electrode 110, and the width of the support member 200 is the width of the support member 200 along the direction of the negative electrode 120 extending beyond the positive electrode 110.

[0027] For example, the width of the negative electrode 120 extending beyond the positive electrode 110 is set to 0.6 mm-5 mm; the width of the support member 200 along the direction of the negative electrode 120 extending beyond the positive electrode 110 is set to 0.3 mm-5 mm. The thickness of the support member 200 is set to 60 μm-400 μm; the thickness of the positive electrode 110 is in the range of 70 μm-500 μm.

[0028] Specifically, the positive electrode 110 includes a positive current collector 112 and a positive active material layer 113, and the negative electrode 120 includes a negative current collector and a negative active material layer. The positive current collector 112 is not particularly limited, as long as it is conductive and will not cause adverse chemical changes in the battery. It can be made of materials such as stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel that has undergone surface treatment with one of carbon, nickel, titanium, or silver. The negative current collector can be made of copper, stainless steel, nickel, titanium, etc. In a specific embodiment, the positive electrode can be made of aluminum, and the negative electrode can be made of copper. The positive active material layer 113 includes a positive active material, including nickel-cobalt-manganese ternary materials, lithium iron phosphate materials, lithium manganese iron phosphate materials, etc. The negative active material layer includes a negative active material, including artificial graphite, natural graphite, silicon-based materials, etc. The solid electrolyte includes sulfide, oxide, and polymer solid electrolytes; specifically, the sulfide in the solid electrolyte can be Li7P3S. 11 Li3PS4 or 80Li2S-20P2S5; polymer solid electrolytes can include polyethylene oxide (PEO), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polypropylene oxide (PPO), polyvinylidene chloride (PVDC), etc.; oxide solid electrolytes include lithium oxide, zirconium oxide, lanthanum oxide, etc.

[0029] It is worth noting that, unlike conventional battery assembly processes, solid-state batteries eliminate the separator. Conventional batteries include a positive electrode, a negative electrode, and a separator, with an adhesive layer on the separator for bonding to the positive and negative electrodes. The positive electrode 110, negative electrode 120, and solid electrolyte layer 130 require greater pressure to achieve a tight fit between them, preventing poor lithium-ion transport among these components, which would result in high ion transport impedance and negatively impact battery performance. Therefore, high pressure is required during solid-state battery assembly. This pressing typically uses an isostatic press or a warm isostatic press, with a pressure range of 200MPa-1000MPa. By controlling the hardness of the support member 200 to be greater than a preset hardness, its support effect on the two adjacent solid electrolyte layers 130 is ensured. For example, the Shore hardness of the support member 200 is 30HA-90HA. The hardness of the support component 200 can be tested using a Shore hardness tester. The testing method can refer to the national standard GB / 531.1-2008, and no specific limitations are made here. The Shore hardness of the support component 200 can be set to 40HA, 50HA, 60HA, 70HA, 80HA, etc.

[0030] Optionally, the shrinkage rate of the support 200 is not less than the shrinkage rate of the positive electrode 110 to avoid excessive shrinkage of the support 200 during the pressing process, which could lead to compression of the solid electrolyte layer 130. For example, the difference between the shrinkage rate of the support 200 and the shrinkage rate of the positive electrode 110 is 0.5%-8%; and / or the shrinkage rate of the support 200 ranges from 1%-15%, and the shrinkage rate of the positive electrode 110 ranges from 3%-12%. Specifically, the difference between the shrinkage rate of the support member 200 and the shrinkage rate of the positive electrode 110 can be set to 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, etc.; the shrinkage rate of the support member 200 can be set to 2%, 4%, 6%, 8%, 10%, 12%, 14%, etc.; and the shrinkage rate of the positive electrode 110 can be set to 4%, 6%, 8%, 10%, etc.

[0031] The shrinkage rate can be measured as follows: Disassemble the empty solid-state battery, remove the cell, clean and dry it, measure the width of the support 200 and the positive electrode 110 before isostatic pressing, seal the cell in a nylon bag and evacuate it, place the sealed cell in the isostatic pressing chamber, apply pressure, and hold the pressure for 10 minutes after the pressure reaches the set pressure value of 600MPa. Release the pressure and remove the cell, and measure the width of the support 200 and the width of the positive electrode 110 after isostatic pressing; Shrinkage rate = (width (after isostatic pressing) / width (before isostatic pressing) - 1) * 100%.

[0032] In one embodiment, the negative electrode 120 extends circumferentially beyond the positive electrode 110. Correspondingly, the support member 200 is a frame structure, i.e., the support member 200 is annular and fitted around the edge of the positive electrode 110. The frame structure is an insulating frame, which is simple in structure and only needs to be fitted around the circumference of the positive electrode 110 during assembly. The insulating frame also provides more reliable support. Furthermore, the insulating frame is made of an insulating material, providing good insulation performance. For example, the insulating frame material can be PTFE, PE, PET, PI, PC, etc. Optionally, the insulating frame can be integrally formed or divided into several parts, i.e., formed by splicing together several parts; no specific limitation is made here.

[0033] Furthermore, the support member 200 is fitted to the outer wall of the positive electrode 110, or the distance between the support member 200 and the outer wall of the positive electrode 110 is less than or equal to 1 mm, that is, the support member 200 is positioned as close as possible to the outer wall of the positive electrode 110 to improve the support effect. For example, a / b is set to 0.6-1, meaning the width of the support member 200 along the direction of the negative electrode 120 extending beyond the positive electrode 110 can be set wider to increase the support width of the support member 200 for the solid electrolyte layer 130 in this direction. Specifically, a / b can be set to 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0034] Optionally, the four corners of the insulating frame can be set as right angles, or at least one of the four corners of the insulating frame can be set as rounded corners. Rounded corners can reduce stress concentration at the corners of the insulating frame, thereby reducing damage to the solid electrolyte layer 130. For example, all four corners of the insulating frame are set as rounded corners.

[0035] Specifically, the solid electrolyte layer 130 and the negative electrode 120 have the same area and are arranged overlappingly. Correspondingly, a / b is set to 0.6-1, meaning that when the solid electrolyte layer 130 and the negative electrode 120 have the same area, the width of the support member 200 along the direction of the negative electrode 120 extending beyond the positive electrode 110 can be set wider to improve the support for the solid electrolyte layer 130. This prevents the portion of the solid electrolyte layer 130 extending beyond the positive electrode 110 from cracking during pressing. Specifically, a / b can be set to 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0036] Preferably, the insulating frame is bonded to the solid electrolyte layer 130. That is, during assembly, adhesive can be applied to the corresponding positions of the insulating frame and / or the solid electrolyte layer 130 to form an adhesive layer 300 before assembly, which can improve the reliability of the connection between the insulating frame and the solid electrolyte layer 130.

[0037] It is worth noting that the support member 200 can be one or more. When there are two or more support members 200, they are stacked between the solid electrolyte layers 130 on both sides of the positive electrode 110, and the sum of the thicknesses of the two or more support members 200 is set to h3, with h3 / h2 set to 0.6-1. Optionally, adjacent support members 200 can also be bonded together to improve the reliability of the connection between them. Specifically, h3 / h2 can be set to 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0038] like Figure 3 As shown, the positive electrode 110 is further provided with a positive electrode tab 111, which is used to make an electrical connection with the external electrode terminal to realize current transmission. The positive electrode tab 111 passes between two support members 200. This arrangement can reduce the damage to the positive electrode tab 111 caused by the support members 200 after they are installed. The thickness of the support member 200 can be set according to the distance between the positive electrode tab 111 and the two side planes of the positive electrode 110, so that the support members 200 will not generate shear force on the positive electrode tab 111 when it passes between the two support members 200, thus ensuring the reliability of the connection between the positive electrode tab 111 and the electrode, and thus realizing the smooth transmission of current.

[0039] In other embodiments, the support 200 is formed of an adhesive layer, that is, adhesive is coated around the positive electrode 110, and the support 200 is formed after the adhesive has cured.

[0040] Optionally, the adhesive layer can be set as an insulating adhesive to achieve the same insulating effect as the insulating frame. Types of insulating adhesives include hot melt adhesives (polyolefin hot melt adhesives, ethylene and its copolymers hot melt adhesives, polyester hot melt adhesives, polyimide hot melt adhesives, polyurethane hot melt adhesives, styrene and its block copolymers hot melt adhesives); UV-curable adhesives (unsaturated polyester resin systems, polyacrylates, epoxy acrylates, polyurethane acrylates, polythiol-polyene systems, cationic curing base resins), alumina slurries, epoxy resin slurries, etc. Alternatively, a solid electrolyte slurry can be used. After the solid electrolyte slurry cures and forms a support 200 which is placed outside the positive electrode 110, it can have the same performance as the solid electrolyte layer 130 as the insulating frame, thus conducting lithium ions, while the insulating frame does not have this function. The electrolyte slurry can specifically include sulfides, oxides, and polymer solid electrolytes.

[0041] Those skilled in the art can select the coating material, coating method, and curing method according to actual needs, without making specific limitations here.

[0042] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A solid-state battery, characterized in that, It includes a positive electrode (110) and a negative electrode (120) stacked in sequence, and a solid electrolyte layer (130) is provided between the positive electrode (110) and the negative electrode (120). At least one edge of the negative electrode (120) extends beyond the positive electrode (110) by a distance b. The solid-state battery also includes a support member (200), which is disposed outside the positive electrode (110) and is positioned corresponding to the position where the negative electrode (120) extends beyond the positive electrode (110). The thickness of the support member (200) in the direction perpendicular to the positive electrode (110) is set to h1, the thickness of the positive electrode (110) is set to h2, and the ratio of h1 to h2 is set to 0.6-1. The width of the support member (200) in the direction where the negative electrode (120) extends beyond the positive electrode (110) is a, and the ratio of a to b is set to 0.5-1.

2. The solid-state battery according to claim 1, characterized in that, The edges of the negative electrode (120) extend beyond the positive electrode (110), and the support (200) is configured as a frame structure.

3. The solid-state battery according to claim 2, characterized in that, The frame structure can be integrated or divided into separate parts.

4. The solid-state battery according to claim 1, characterized in that, The solid electrolyte layer (130) and the negative electrode (120) have the same area and are arranged in an overlapping manner, with a / b set to 0.6-1.

5. The solid-state battery according to claim 4, characterized in that, The support (200) is bonded to the solid electrolyte layer (130).

6. The solid-state battery according to claim 1, characterized in that, The distance between the support member (200) and the outer wall of the positive electrode (110) is less than or equal to 1 mm, and a / b is set to 0.6-1.

7. The solid-state battery according to claim 1, characterized in that, The support (200) is formed of an adhesive layer.

8. The solid-state battery according to claim 7, characterized in that, The adhesive layer is configured as a solid electrolyte slurry.

9. The solid-state battery according to claim 1, characterized in that, The hardness of the support member (200) is greater than the preset hardness.

10. The solid-state battery according to claim 9, characterized in that, The Shore hardness of the support (200) is 30HA-90HA.

11. The solid-state battery according to claim 1, characterized in that, The shrinkage rate of the support (200) is not less than the shrinkage rate of the positive electrode (110).

12. The solid-state battery according to claim 11, characterized in that, The difference between the shrinkage rate of the support (200) and the shrinkage rate of the positive electrode (110) is 0.5%-8%; and / or the shrinkage rate of the support (200) is in the range of 1%-15%, and the shrinkage rate of the positive electrode (110) is in the range of 3%-12%.

13. The solid-state battery according to any one of claims 1-12, characterized in that, There are two or more support members (200), and the sum of the thicknesses of the two or more support members (200) is set to h3, and the ratio of h3 to h2 is set to 0.6-1.

14. The solid-state battery according to claim 13, characterized in that, The positive electrode plate (110) is provided with a positive electrode tab (111), which is inserted between the two support members (200).

15. The solid-state battery according to claim 13, characterized in that, Two or more of the aforementioned support members (200) are bonded together.

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