Solid-state battery processing method

Abstract

The invention relates to the technical field of solid-state batteries, and discloses a solid-state battery processing method. The solid-state battery processing method comprises the following steps that a positive plate and a negative plate are sequentially stacked to form a battery cell unit, a solid-state electrolyte layer is arranged between the positive plate and the negative plate, at least one side of the negative plate in the circumferential direction exceeds the positive plate, and an overhang area is formed; placing the battery cell units along the vertical direction; pouring glue is arranged in the overhang area, and a protective layer is formed after the pouring glue is cured; and pressing the battery cell unit to form the solid-state battery. According to the invention, the possibility of short circuit in an overhang area is effectively reduced, and the safety and reliability of the solid-state battery are improved; meanwhile, the efficiency is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a solid-state battery processing method. Background Art

[0002] All-solid-state batteries are batteries that use solid electrolytes. Since all-solid-state batteries use solid electrolytes instead of liquid organic electrolytes, the safety performance of the battery is greatly improved. During the assembly process of all-solid-state batteries, a lot of pressure is required for pressing. Since all-solid-state batteries use traditional pole pieces with large negative poles and small positive poles, an overhang area is formed in the circumference of the positive pole piece. Under high pressure, the shear force generated between the pole pieces can easily cause the solid electrolyte layer to rupture, causing a short circuit problem.

[0003] In the prior art, the above problem is solved by providing a structure with insulating properties on the positive electrode sheet, but the efficiency is low.

[0004] Therefore, a solid-state battery processing method is urgently needed to solve the above problems. Summary of the invention

[0005] Based on the above, the purpose of the present invention is to provide a solid-state battery processing method, which effectively reduces the possibility of short circuit in the overhang area, improves the safety and reliability of the solid-state battery; and at the same time is more efficient.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A solid-state battery processing method comprises the following steps:

[0008] The positive electrode sheet and the negative electrode sheet are stacked in sequence to form a battery cell unit, and a solid electrolyte layer is arranged between the positive electrode sheet and the negative electrode sheet, and at least one side of the negative electrode sheet is arranged beyond the positive electrode sheet in a circumferential direction to form an overhang area;

[0009] Placing the battery cell unit in a vertical direction;

[0010] Providing a potting glue in the overhang area, wherein the potting glue forms a protective layer after being cured;

[0011] The battery cell units are pressed to form a solid-state battery.

[0012] The beneficial effects of the present invention are:

[0013] The present invention first forms a battery cell unit by stacking the positive electrode sheet and the negative electrode sheet in sequence, and a solid electrolyte layer is arranged between the adjacent electrode sheets of the battery cell unit. Since the area of ​​the positive electrode sheet is smaller than the area of ​​the negative electrode sheet, an overhang area is arranged between at least one side of the circumference of the positive electrode sheet and the negative electrode sheet. In order to avoid the shear force from easily causing the solid electrolyte layer in the corresponding overhang area to rupture when the solid-state battery is pressed, thereby causing a short circuit problem, before pressing, a perfusion glue is also arranged in the overhang area, so that the perfusion glue can play a supporting role in the overhang area after curing, thereby avoiding the rupture of the solid electrolyte layer. Specifically, before setting the perfusion glue, the battery cell unit needs to be placed vertically, the overhang area is filled by the fluidity of the perfusion glue, and then a protective layer is formed by curing the perfusion glue to achieve effective support for the solid electrolyte layer in the circumference of the positive electrode sheet, thereby avoiding short circuit after pressing, and improving the safety and reliability of the solid-state battery. In addition, the above-mentioned glue coating method can be completed at one time, without the need to fill the overhang area in the circumference of each positive electrode sheet, and the processing efficiency is more rigid. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0015] Figure 1 It is a schematic diagram of the relationship between the negative electrode sheet, positive electrode sheet, solid electrolyte layer and overhang area of ​​the solid-state battery;

[0016] Figure 2 is a flow chart of a solid-state battery processing method provided by a specific embodiment of the present invention;

[0017] Figure 3 It is a schematic diagram of injecting glue into a vertically placed battery cell unit using a solid-state battery processing method provided in a specific embodiment of the present invention.

[0018] In the figure:

[0019] 100, battery cell; 101, overhang area; 110, negative electrode sheet; 120, positive electrode sheet; 130, solid electrolyte layer;

[0020] 200, glue gun;

[0021] 300. Scraper. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0024] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0026] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0027] like Figure 1-Figure 3As shown, this embodiment provides a solid-state battery processing method, which includes the following steps: stacking the positive electrode sheet 120 and the negative electrode sheet 110 in sequence to form a battery cell unit 100, and a solid electrolyte layer 130 is arranged between the positive electrode sheet 120 and the negative electrode sheet 110, and the negative electrode sheet 110 is arranged to extend beyond the positive electrode sheet 120 on at least one side in the circumferential direction to form an overhang area 101; placing the battery cell unit 100 in a vertical direction; providing a potting glue in the overhang area 101, and forming a protective layer after the potting glue is cured; and pressing the battery cell unit 100 to form a solid-state battery.

[0028] First, the positive electrode sheet 120 and the negative electrode sheet 110 are stacked in sequence to form a battery cell unit 100, and a solid electrolyte layer 130 is arranged between adjacent electrode sheets of the battery cell unit 100. Since the area of ​​the positive electrode sheet 120 is smaller than that of the negative electrode sheet 110, an overhang area 101 is arranged between at least one side of the circumference of the positive electrode sheet 120 and the negative electrode sheet 110. In order to prevent the shear force from easily causing the solid electrolyte layer 130 corresponding to the overhang area 101 to rupture when the solid-state battery is pressed, thereby causing a short circuit problem, before pressing, a potting glue is also arranged in the overhang area 101, so that the potting glue can play a supporting role for the overhang area 101 after curing, thereby preventing the solid electrolyte layer 130 from rupturing. Specifically, before setting the potting glue, the battery cell unit 100 needs to be placed vertically, and the overhang area 101 is filled by the fluidity of the potting glue, and then the potting glue is solidified to form a protective layer to effectively support the solid electrolyte layer 130 around the positive electrode sheet 120, thereby avoiding short circuits after pressing, and improving the safety and reliability of the solid-state battery. In addition, the above-mentioned glue coating method can be completed at one time, without filling the overhang area 101 around each positive electrode sheet 120, and the processing efficiency is more rigid.

[0029] Specifically, the positive electrode sheet 120 includes a positive electrode current collector and a positive electrode active material layer, and the negative electrode sheet 110 includes a negative electrode current collector and a negative electrode active material layer. There is no particular limitation on the positive electrode current collector, as long as it has conductivity and does not cause adverse chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, fired carbon, or aluminum or stainless steel that has been surface-treated with one of carbon, nickel, titanium, silver, etc. can be used; the negative electrode current collector can be copper, stainless steel, nickel, titanium, etc. In a specific embodiment, aluminum can be used for the positive electrode, and copper can be used for the negative electrode. The positive electrode active material layer includes a positive electrode active material, and the positive electrode active material includes a nickel-cobalt-manganese ternary material, a lithium iron phosphate material, a lithium iron manganese phosphate material, etc.; the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material includes artificial graphite, natural graphite, silicon-based materials, etc. The solid electrolyte includes sulfides, oxides, 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.

[0030] It is worth noting that by placing the battery cell unit 100 vertically and then providing the potting glue, the fluidity of the potting glue can be utilized for potting, so that the overhang area 101 can be fully filled.

[0031] Accordingly, the potting glue should have a certain fluidity to fully fill the overhang area 101. Since the potting glue is applied after the battery cell 100 is assembled, the battery cell 100 is placed vertically, and then the potting glue is applied. Therefore, the viscosity of the potting glue cannot be too large to prevent the glue from flowing into the battery cell 100 and affecting the lithium ion transmission inside the battery cell 100. At the same time, the viscosity of the potting glue cannot be too large. If it is too large, it will be unfavorable for the potting glue to spread, resulting in the glue layer being too thick in some areas, thin in some areas, and uneven in the glue layer, which will affect the effect of the subsequent protective layer and still cause a high risk of short circuit between the positive and negative electrodes. Exemplarily, the viscosity range of the potting glue is set at 800Pa.s-65000mPa.s.

[0032] Optionally, the injection glue is set to solid electrolyte slurry, and the solid electrolyte slurry is made of the same material as the solid electrolyte layer 130, and plays the role of conducting lithium ions. It can be understood that by adopting the above method, the solid electrolyte slurry has the same physical and chemical properties as the solid electrolyte layer 130 after curing, that is, the overhang area 101 can be used as the solid electrolyte layer 130, which is conducive to improving the performance of the solid-state battery.

[0033] Exemplarily, the solid electrolyte slurry may include sulfides, oxides, and polymer solid electrolytes. Those skilled in the art may set it according to the material of the actual solid electrolyte layer 130 of the solid-state battery to ensure that the solid-state battery has good performance. In other embodiments, the potting glue may also be set to other types of insulating glue in addition to the solid electrolyte slurry. The cured insulating glue makes the overhang area 101 an insulating area and cannot play the role of conducting lithium ions. The types of insulating glue also include the following types: hot melt glue (polyolefin hot melt glue, ethylene and its copolymer hot melt glue, polyester hot melt glue, polyimide hot melt glue, polyurethane hot melt glue, styrene and its block copolymer hot melt glue); light curing glue (unsaturated polyester resin system, polyacid acrylate, epoxy acrylate, polyurethane acrylate, polythiol-polyene system, cationic curing base resin), alumina slurry, epoxy resin glue slurry, etc.

[0034] Specifically, the glue gun 200 is used to set the overhang area 101 with the potting glue, and the glue gun 200 is connected to the potting glue supply device, or the glue gun 200 stores the potting glue. At the same time, the width of the glue outlet of the glue gun 200 is not less than the thickness of the battery cell unit 100, so that the glue injection of all the overhang areas 101 of the battery cell unit 100 can be completed in one time, which is beneficial to improve the consistency of the glue injection between multiple overhang areas 101 while improving the efficiency of the glue injection. It can be understood that the width of the glue outlet is the width of the glue outlet along the thickness direction of the battery cell unit 100, and the thickness direction of the battery cell unit 100 is the direction in which the positive electrode sheet 120 and the negative electrode sheet 110 are stacked in sequence.

[0035] Furthermore, the glue outlet of the glue gun 200 is set at an angle to the overhang area 101 and is tilted toward the direction of movement of the glue gun 200, so that the operator can observe the glue outlet. At the same time, the glue gun 200 moves at a preset speed to apply glue, ensuring that the injection glue can fill the overhang area 101 without causing excessive application. The preset speed is related to the viscosity of the injection glue, and those skilled in the art can set it according to actual conditions, and no specific limitation is made here. Optionally, the angle between the glue outlet and the overhang area 101 is set to 5°-75°; the angle between the glue outlet and the overhang area 101 cannot be too large to prevent the glue from directly impacting the battery cell 100 and flowing into the battery cell 100, affecting the lithium ion transmission; the angle between the glue outlet and the overhang area 101 cannot be too small to prevent the glue gun and the battery cell 100 from interfering and damaging the battery cell 100; specifically, the angle between the glue outlet and the overhang area 101 can be set to 10°, 20°, 30°, 40°, 50°, 60°, 70°, etc. The preset speed is set to 40mm / s-200mm / s. The speed cannot be too fast, resulting in uneven coating, nor too slow. If it is too slow, it may cause poor continuity of the glue layer coating and uneven coating. Specifically, the preset speed is set to 50mm / s, 70mm / s, 90mm / s, 110mm / s, 130mm / s, 150mm / s, 170mm / s, 190mm / s, etc.

[0036] Preferably, after the glue gun 200 is used to set the potting glue to the overhang area 101, the potting glue outside the overhang area 101 is scraped off to avoid the potting glue outside the overhang area 101 from affecting the solid-state battery assembly after curing. The outside of the overhang area 101 includes the surface and side of the battery cell unit 100, and accordingly, the scraper 300 can be set to be L-shaped.

[0037] It is worth noting that the formed protective layer does not protrude from the edge of the negative electrode sheet 110. By avoiding the protruding arrangement of the protective layer, interference problems in the subsequent assembly of the battery cell unit 100 can be effectively reduced, such as interference with the battery cell unit 100 being placed in a shell or a packaging bag.

[0038] In this embodiment, the negative electrode sheet 110 is arranged circumferentially beyond the positive electrode sheet 120, and the pouring glue into the overhang area 101 includes: pouring glue on the side of the overhang area 101 located at the top; then rotating the battery cell unit 100 so that the other side of the overhang area 101 of the battery cell unit 100 faces upward, and then pouring glue on the side until the four sides of the overhang area 101 are all filled with pouring glue. The above operation allows the glue gun 200 to only inject glue on the side located at the top, which is convenient for filling the pouring glue with its own fluidity, so that the injection effect is better.

[0039] Optionally, for the curing operation, the curing operation can be performed after each side of the potting glue is set, and then the battery cell unit 100 is rotated, that is, the steps of injection-curing-rotation-injection-curing-rotation-injection-curing-rotation-injection-curing-rotation-injection-curing, the above steps will cure the potting glue as soon as possible to reduce the influence of the fluidity of the potting glue on the filling effect. Alternatively, the overhang area 101 can be set with potting glue before the curing operation, that is, the steps of injection-rotation-injection-rotation-injection-rotation-injection-curing are followed. The above steps reduce the number of curing times and simplify the process.

[0040] It is worth noting that the second curing operation can use a potting glue with a higher viscosity. By way of example, the viscosity of the potting glue is set to 1000Pa.s-65000Pa.s, and can be specifically set to 5000Pa.s, 15000Pa.s, 20000Pa.s, 25000Pa.s, 30000Pa.s, 35000Pa.s, 40000Pa.s, 45000Pa.s, 50000Pa.s, 55000Pa.s, 60000Pa.s, etc., to reduce the filling effect problem caused by excessive flow of the potting glue during the spin coating process. Correspondingly, the viscosity of the potting glue in the second curing operation is set to 800Pa.s-60000Pa.s, and can be specifically set to 1000Pa.s, 5000Pa.s, 15000Pa.s, 20000Pa.s, 25000Pa.s, 30000Pa.s, 35000Pa.s, 40000Pa.s, 45000Pa.s, 50000Pa.s, 55000Pa.s, etc.

[0041] It is worth noting that the four corners of the overhang area 101 (such as Figure 3 The operation of setting the potting glue is performed only once (the position indicated by the middle dotted line), which can avoid excessive potting glue at the four corners of the overhang area 101, and is beneficial to improving the consistency of the thickness of each part of the overhang area 101.

[0042] Exemplarily, when the pouring glue is set on the first side where the overhang area 101 is located above, the pouring glue is only set on the position overlapping with the positive electrode sheet 120 on this side. That is, when applying glue on the first side, only the overhang area 101 above the positive electrode sheet 120 is applied, and the two ends of this side are not applied first, so as to avoid the loss of end pouring glue caused by the flow of the pouring glue at both ends. When applying glue on the second side, since the front end of this side has been applied with glue, the distance that needs to be applied on the second side is the front end of this side and the overhang area 101 above the positive electrode sheet 120 on this side, that is, the rear end of this side is not temporarily applied with glue. The application of glue on the third side is the same as that on the second side. When applying glue on the fourth side, since the front end and the rear end of this side have been applied with glue, the distance that needs to be applied on the fourth side is the front end, the rear end and the overhang area 101 above the positive electrode sheet 120 on this side.

[0043] In other embodiments, baffles may be provided at the four corners of the overhang area 101 to achieve only one operation of setting the glue at the four corners of the overhang area 101, thereby avoiding problems such as excessive or missing glue at the four corners.

[0044] Optionally, the curing setting is self-curing, light curing, or heat curing. Self-curing can reduce equipment investment and reduce operation steps; the light lamp can use an ultraviolet lamp; heat curing can be done by hot air and / or a heating tube. Those skilled in the art can select the curing method according to the type of potting glue actually selected, and no specific limitation is made here.

[0045] Furthermore, in the pressing step of the battery cell operation, the pressing pressure is set to a preset pressure, and optionally, the preset pressure is set to 400Mpa-800Mpa to ensure that the contact between the positive electrode sheet 120, the negative electrode sheet 110 and the solid electrolyte layer 130 can meet the normal discharge of the solid-state battery. It is worth noting that under the pressing of the preset pressure, the shrinkage rate of the multiple protective layers is greater than or equal to the shrinkage rate of the battery cell unit 100, so as to ensure that the solid electrolyte layer 130 is not damaged due to too small shrinkage of the protective layer during the pressing process.

[0046] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there will be changes in the specific implementation methods and application scopes. The content of this specification should not be understood as limiting the present invention.

Claims

1. A solid-state battery processing method, characterized in that: The steps include: A plurality of positive electrode sheets (120) and a plurality of negative electrode sheets (110) are stacked in sequence to form a battery cell unit (100), a solid electrolyte layer (130) is arranged between adjacent positive electrode sheets (120) and negative electrode sheets (110), and at least one side of the negative electrode sheet (110) is arranged beyond the positive electrode sheet (120) in a circumferential direction to form an overhang region (101); Placing the battery cell unit (100) in a vertical direction; Providing a potting glue in the overhang area (101), wherein the potting glue forms a protective layer after being cured; The battery cell unit (100) is pressed to form a solid-state battery.

2. The solid-state battery processing method according to claim 1, characterized in that: The potting glue is configured as a solid electrolyte slurry, and the solid electrolyte slurry is made of the same material as the solid electrolyte layer (130).

3. The solid-state battery processing method according to claim 1, characterized in that: The potting glue is applied to the overhang area (101) by means of a glue gun (200), and the width of the glue outlet of the glue gun (200) is not less than the thickness of the battery cell unit (100).

4. The solid-state battery processing method according to claim 3, characterized in that: The glue outlet of the glue gun (200) forms an angle with the overhang area (101) and moves at a preset speed to apply glue.

5. The solid-state battery processing method according to claim 1, characterized in that: After the potting glue is provided on the overhang area (101), the method further comprises: scraping off the potting glue located outside the overhang area (101).

6. The solid-state battery processing method according to claim 1, characterized in that: The negative electrode sheet (110) is arranged to extend beyond the positive electrode sheet (120) in the circumferential direction, and the potting glue is arranged in the overhang area (101), comprising: setting the potting glue on the side of the overhang area (101) located above, rotating the battery cell unit (100), and then setting the potting glue on the side of the overhang area (101) located above, until the potting glue is arranged on all four sides of the overhang area (101).

7. The solid-state battery processing method according to claim 6, characterized in that: When the potting glue is provided on the first side of the overhang area (101) located above, the potting glue is only provided on the position of the side overlapping with the positive electrode sheet (120).

8. The solid-state battery processing method according to claim 6, characterized in that: After setting the potting glue on one side, a curing operation is performed, and then the battery cell unit (100) is rotated; the viscosity of the potting glue is set to 800 Pa.s-60000 Pa.s.

9. The solid-state battery processing method according to claim 6, characterized in that: After the overhang area (101) is completely filled with the potting glue, a curing operation is performed; the viscosity of the potting glue is set to 1000 Pa.s-65000 Pa.s.

10. The solid-state battery processing method according to claim 6, characterized in that: The four corners of the overhang area (101) are provided with the potting glue only once.

11. The solid-state battery processing method according to claim 1, characterized in that: The curing is configured as self-curing, light curing, or heat curing.

12. The solid-state battery processing method according to claim 1, characterized in that: The battery cell unit (100) is pressed with a preset pressure, and under the pressing with the preset pressure, the shrinkage rate of the plurality of protective layers is greater than or equal to the shrinkage rate of the battery cell unit (100).

13. The solid-state battery processing method according to any one of claims 1 to 12, characterized in that: The protective layer does not protrude from the edge of the negative electrode sheet (110).

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