Solid-state battery processing method

Abstract

The present application relates to the technical field of solid-state battery, and discloses a solid-state battery processing method. The solid-state battery processing method comprises the following steps: stacking positive electrode sheets and negative electrode sheets in sequence to form a battery cell unit, a solid-state electrolyte layer is arranged between the positive electrode sheets and the negative electrode sheets, the negative electrode sheet is arranged to protrude beyond the positive electrode sheet on at least one side in the circumferential direction, and an overhang region is formed; the battery cell unit is placed in the vertical direction; a filling glue is arranged in the overhang region, and a protective layer is formed after the filling glue is cured; and the battery cell unit is pressed to form a solid-state battery. The present application effectively reduces the possibility of short circuit in the overhang region, improves the safety and reliability of the solid-state battery, and is more efficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-state battery, and particularly relates to a solid-state battery processing method. BACKGROUND

[0002] The all-solid-state battery is a battery using a solid-state electrolyte. The all-solid-state battery greatly improves the safety performance of the battery because the all-solid-state battery uses a solid-state electrolyte instead of a liquid organic electrolyte. A large pressure is needed for pressing during the assembly of the all-solid-state battery. Because the all-solid-state battery adopts a traditional negative electrode large and a positive electrode small, an overhang region is formed in the circumferential direction of the positive electrode. Under high pressure, the shear force generated between the electrode sheets easily causes the solid-state electrolyte layer to break, thereby causing a short circuit problem.

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

[0004] Therefore, there is an urgent need for a solid-state battery processing method to solve the above problems. SUMMARY

[0005] Based on the above, the purpose of the present application is to provide a solid-state battery processing method which effectively reduces the possibility of short circuit of the overhang region and improves the safety and reliability of the solid-state battery; and the efficiency is higher.

[0006] To achieve the above purpose, the present application adopts the following technical scheme:

[0007] The 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-state electrolyte layer is arranged between the positive electrode sheet and the negative electrode sheet, and the negative electrode sheet is arranged to protrude beyond the positive electrode sheet on at least one side in the circumferential direction and form an overhang region;

[0009] The battery cell unit is placed in the vertical direction;

[0010] A filling glue is arranged in the overhang region, and the filling glue forms a protective layer after curing;

[0011] The battery cell unit is pressed to form a solid-state battery.

[0012] The present application has the following beneficial effects:

[0013] The application firstly forms an electric core unit by stacking the positive electrode sheet and the negative electrode sheet in turn, and a solid-state electrolyte layer is arranged between adjacent electrode sheets of the electric core 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 circumferential direction of the positive electrode sheet and the negative electrode sheet. In order to avoid the solid-state electrolyte layer corresponding to the overhang area from being broken due to the shearing force when the solid-state battery is pressed, a filling glue is arranged in the overhang area before pressing, so that the filling glue can play a supporting role on the overhang area after solidification, thereby avoiding the solid-state electrolyte layer from being broken. Specifically, the electric core unit needs to be placed vertically before the filling glue is arranged, the overhang area is filled by the flowability of the filling glue, and then a protection layer is formed by solidification of the filling glue, so as to effectively support the solid-state electrolyte layer in the circumferential direction 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 glue coating method can be completed at one time, and it is not necessary to fill the overhang area in the circumferential direction of each positive electrode sheet, so that the processing efficiency is higher. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the contents of the embodiments of the present application and the drawings.

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

[0016] Fig. 2 is a flowchart of a solid-state battery processing method provided by the specific embodiment of the present application;

[0017] Fig. 3 is a schematic diagram of injecting glue into the vertically placed electric core unit by using the solid-state battery processing method provided by the specific embodiment of the present application.

[0018] In the drawings:

[0019] 100, electric core unit; 101, overhang area; 110, negative electrode sheet; 120, positive electrode sheet; 130, solid-state electrolyte layer;

[0020] 200, glue gun;

[0021] 300, doctor blade. DETAILED DESCRIPTION

[0022] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same or like components or elements having the same or similar functions. The embodiments described below are exemplary and intended to provide an explanation of the present application and are not intended to restrict the present application.

[0023] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are only for descriptive purposes 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 explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "above", "over" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The "below", "under" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0026] The technical solutions of the present application are further illustrated below in conjunction with the drawings and through specific embodiments.

[0027] As Figs. 1-3As shown, the 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 the battery cell unit 100, and the solid-state 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 beyond the positive electrode sheet 120 at least on one side in the circumferential direction to form an overhang area 101; placing the battery cell unit 100 along the vertical direction; arranging the pouring glue into the overhang area 101, and the pouring glue forms a protective layer after curing; and pressing the battery cell unit 100 to form a solid-state battery.

[0028] First, by stacking the positive electrode sheet 120 and the negative electrode sheet 110 in sequence to form the battery cell unit 100, and the solid-state electrolyte layer 130 is arranged between the adjacent electrode sheets of the battery cell unit 100. Since the area of the positive electrode sheet 120 is smaller than the area of the negative electrode sheet 110, the overhang area 101 is arranged between at least one side of the positive electrode sheet 120 and the negative electrode sheet 110 in the circumferential direction. In order to avoid the shear force causing the solid-state electrolyte layer 130 corresponding to the overhang area 101 to be broken during the pressing to form the solid-state battery, thereby causing a short circuit problem, the pouring glue is arranged into the overhang area 101 before pressing, so that the pouring glue can support the overhang area 101 after curing, thereby avoiding the solid-state electrolyte layer 130 from being broken. Specifically, the battery cell unit 100 needs to be placed vertically before the pouring glue is arranged, and the overhang area 101 is filled by the flowability of the pouring glue, and then the protective layer is formed by curing the pouring glue, so as to effectively support the solid-state electrolyte layer 130 in the circumferential direction of the positive electrode sheet 120, thereby avoiding the short circuit after pressing, and improving the safety and reliability of the solid-state battery. In addition, the above-mentioned gluing method can be completed at one time, and it is not necessary to fill the overhang area 101 in the circumferential direction of each positive electrode sheet 120, and the processing efficiency is higher.

[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. The positive electrode current collector is not particularly limited as long as it has electrical conductivity without causing adverse chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium, baked carbon, or aluminum or stainless steel treated on the surface with one of carbon, nickel, titanium, silver, etc. can be used; the negative electrode current collector can be made of copper, stainless steel, nickel, titanium, etc. In specific embodiments, the positive electrode can be made of aluminum, and the negative electrode can be made of copper. The positive electrode active material layer includes a positive electrode active material, and the positive electrode active material includes nickel-cobalt-manganese ternary material, lithium iron phosphate material, lithium manganese iron 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 material, etc. The solid-state electrolyte includes sulfide, oxide, and polymer solid-state electrolyte; specifically, the sulfide in the solid-state electrolyte can be Li7P3S 11 , Li3PS4, or 80Li2S-20P2S5; the polymer solid-state electrolyte can be polyethylene oxide PEO, polyacrylonitrile PAN, polyvinylidene fluoride PVDF, polymethyl methacrylate PMMA, polypropylene oxide PPO, polyvinylidene chloride PVDC, etc.; the oxide solid-state electrolyte includes lithium oxide, zirconium oxide, lanthanum oxide, etc.

[0030] It is worth noting that by placing the battery cell unit 100 vertically and then setting the pouring glue, the pouring glue can be poured by taking advantage of its fluidity, so that the overhang area 101 can be fully filled.

[0031] Correspondingly, the pouring glue should have a certain fluidity to fully fill the overhang area 101. Since the pouring glue is performed after the battery cell unit 100 is assembled, the battery cell unit 100 is placed vertically, and then the pouring glue is set, the viscosity of the pouring glue cannot be too large, so as to avoid the glue flowing into the battery cell unit 100, affecting the transmission of lithium ions inside the battery cell unit 100; at the same time, the viscosity of the pouring glue cannot be too large, otherwise it is not conducive to the spreading of the pouring glue, causing the glue layer to be too thick in local areas, the glue layer to be thin in local areas, the glue layer to be uneven, affecting the effect of the subsequent protective layer, and still causing the problem of high risk of positive and negative electrode short circuit. Illustratively, the viscosity of the pouring glue is set in the range of 800 Pa.s-65000 mPa.s.

[0032] Optionally, the pouring glue is set as a solid-state electrolyte slurry, which has the same material as the solid-state electrolyte layer 130 and plays a role in conducting lithium ions. It can be understood that by using the above method, the solid-state electrolyte slurry has the same material properties as the solid-state electrolyte layer 130 after solidification, i.e., the overhang area 101 can be used as the solid-state electrolyte layer 130, which is conducive to improving the performance of the solid-state battery.

[0033] Exemplarily, the solid electrolyte slurry can include sulfide, oxide, polymer solid electrolyte, and a person skilled in the art can set 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 injection glue can also be set as other types of insulating glue in addition to the solid electrolyte slurry, and the cured insulating glue makes the overhang area 101 an insulating area and cannot play a role in 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); photocuring glue (unsaturated polyester resin system, polyacrylic acid ester, epoxy acrylate, polyurethane acrylate, polysulfide-polyene system, cationic curing base resin), alumina slurry, epoxy resin glue slurry, etc.

[0034] Specifically, the injection glue is set to the overhang area 101 by the glue gun 200, the glue gun 200 is in communication with the injection glue supply device, or the injection glue is stored in the glue gun 200. 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 injection of all overhang areas 101 of the battery cell unit 100 can be completed at one time, which improves the injection efficiency and is also beneficial to improve the consistency of the injection between multiple overhang areas 101. 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 plate 120 and the negative plate 110 are stacked in turn.

[0035] Furthermore, the nozzle of the glue gun 200 is set at an angle to the overhang area 101 and tilted towards the direction of movement of the glue gun 200, making it easy for the operator to observe the glue dispensing situation. At the same time, the glue gun 200 moves and applies glue at a preset speed to ensure that the glue can fill the overhang area 101 without over-applying. The preset speed is related to the viscosity of the glue, and those skilled in the art can set it according to the actual situation, without making specific limitations here. Optionally, the angle between the glue outlet and the overhang region 101 is set to 5°-75°. The angle should not be too large to prevent the glue from directly impacting the battery cell 100 and flowing into its interior, affecting lithium-ion transport. Conversely, the angle should not be too small to prevent interference between the glue gun and the battery cell 100, which could damage it. Specifically, the angle between the glue outlet and the overhang region 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 should not be too fast, as this will result in uneven coating; nor should it be too slow, as this may lead to poor continuity of the glue layer and uneven coating. Specifically, the preset speeds are set to 50mm / s, 70mm / s, 90mm / s, 110mm / s, 130mm / s, 150mm / s, 170mm / s, 190mm / s, etc.

[0036] Preferably, after applying the potting adhesive to the overhang area 101 using the glue gun 200, the process further includes scraping off the potting adhesive located outside the overhang area 101 to prevent the potting adhesive outside the overhang area 101 from curing and affecting the solid-state battery assembly. The outside of the overhang area 101 includes the surface and side of the cell unit 100, and correspondingly, the scraper 300 can be configured as L-shaped.

[0037] It is worth noting that the formed protective layer does not protrude beyond the edge of the negative electrode 110. By avoiding a protruding protective layer, interference problems that may occur during the subsequent assembly of the cell unit 100 can be effectively reduced, such as interference with the insertion of the cell unit 100 into the casing or packaging bag.

[0038] In this embodiment, the negative electrode 110 extends circumferentially beyond the positive electrode 120. Applying potting compound to the overhang region 101 includes: applying potting compound to the upper side of the overhang region 101; then rotating the cell unit 100 so that the other side of the overhang region 101 faces upwards, and then applying potting compound to that side, until all four sides of the overhang region 101 are covered with potting compound. This operation allows the glue gun 200 to apply compound only to the upper side, facilitating the filling effect by utilizing the fluidity of the potting compound itself.

[0039] Optionally, for the curing operation, curing can be performed after the potting adhesive on each side is applied, followed by rotating the cell unit 100. This involves following the steps of potting adhesive application-curing-rotation-potting adhesive application-curing-rotation-potting adhesive application-curing-rotation-potting adhesive application-curing. These steps ensure the potting adhesive cures as quickly as possible, reducing the impact of its flowability on the filling effect. Alternatively, the potting adhesive can be applied to the entire overhang area 101 before curing, following the steps of potting adhesive application-rotation-potting adhesive application-rotation-potting adhesive application-rotation-potting adhesive application-curing. This reduces the number of curing operations and simplifies the process.

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

[0041] It is worth noting that the four corners of the overhang area 101 (such as...) Fig. 3 The position shown by the dashed line only requires one setting of the potting compound, which can avoid excessive potting compound at the four corners of the overhang area 101 and help improve the consistency of the thickness of the overhang area 101.

[0042] For example, when applying potting compound to the first side of the overhang region 101, the compound is applied only to the area overlapping the positive electrode 120 on that side. That is, when applying compound to the first side, only the overhang region 101 above the positive electrode 120 is coated, while the ends of that side are not coated initially to avoid missing end-capping compound due to flow of the compound at both ends. When applying compound to the second side, since the front end of that side has already been coated, the distance to be coated on the second side is the front end of that side and the overhang region 101 above the positive electrode 120 on that side; that is, the rear end of that side is not coated temporarily. The coating on the third side is the same as on the second side. When applying compound to the fourth side, since both the front and rear ends of that side have already been coated, the distance to be coated on the fourth side is the front end, the rear end of that side, and the overhang region 101 above the positive electrode 120 on that side.

[0043] In other embodiments, baffles can be provided at the four corners of the overhang area 101 to ensure that the four corners of the overhang area 101 are filled with potting adhesive only once, thus avoiding problems such as excessive or missing potting adhesive at the four corners.

[0044] Optionally, the curing method can be self-curing, light-curing, or heat-curing. Self-curing reduces equipment investment and operational steps; ultraviolet lamps can be used for light curing; and heat curing can be achieved through hot air and / or heating elements. Those skilled in the art can select the curing method based on the type of potting adhesive used, and no specific limitations are made here.

[0045] Furthermore, in the pressing step of the battery cell operation, the pressing pressure is set to a preset pressure, optionally set to 400 MPa-800 MPa, to ensure that the contact between the positive electrode 120, the negative electrode 110, and the solid electrolyte layer 130 is sufficient for the normal discharge of the solid-state battery. It is worth noting that under the preset pressure, the shrinkage rate of the multiple protective layers is greater than or equal to the shrinkage rate of the battery cell 100, thereby preventing damage to the solid electrolyte layer 130 due to insufficient shrinkage of the protective layers during the pressing process.

[0046] 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 method of processing a solid-state battery, characterized by, The method comprises the following steps: Stacking a plurality of positive electrode sheets (120) and a plurality of negative electrode sheets (110) to form a battery cell (100), and a solid-state electrolyte layer (130) is arranged between adjacent positive electrode sheets (120) and negative electrode sheets (110), the negative electrode sheet (110) is arranged to be larger than the positive electrode sheet (120) in the circumferential direction, and an overhang area (101) is formed; Place the battery cell (100) in the vertical direction; Set the injection glue on the side of the overhang area (101) above, rotate the battery cell (100), and then set the injection glue on the side of the overhang area (101) above, until the four sides of the overhang area (101) are provided with the injection glue, and the injection glue forms a protective layer after curing; the injection glue is set on the overhang area (101) by a glue gun (200), the width of the glue outlet of the glue gun (200) is not less than the thickness of the battery cell (100); the viscosity of the injection glue is set to 800 Pa.s-65000 Pa.s; Press the battery cell (100) to form a solid-state battery.

2. The solid-state battery processing method of claim 1, wherein, The injection glue is set as a solid-state electrolyte slurry, and the solid-state electrolyte slurry has the same material as the solid-state electrolyte layer (130).

3. The solid-state battery processing method of claim 1, wherein, The glue outlet of the glue gun (200) forms an angle with the overhang area (101) and moves at a preset speed.

4. The solid-state battery processing method of claim 1, wherein, After setting the injection glue on the overhang area (101), the injection glue outside the overhang area (101) is scraped off.

5. The solid-state battery processing method of claim 1, wherein, When setting the injection glue on the first side of the overhang area (101) above, only the position overlapping with the positive electrode sheet (120) on this side is provided with the injection glue.

6. The solid-state battery processing method of claim 1, wherein, After setting the injection glue on each side, the curing operation is performed, and then the battery cell (100) is rotated; the viscosity of the injection glue is set to 800 Pa.s-60000 Pa.s.

7. The solid-state battery processing method of claim 1, wherein, After setting the injection glue on the overhang area (101), the curing operation is performed; the viscosity of the injection glue is set to 1000 Pa.s-65000 Pa.s.

8. The solid-state battery processing method of claim 1, wherein, The four corners of the overhang area (101) are provided with the injection glue only once.

9. The solid-state battery processing method of claim 1, wherein, The curing is set as self-curing, photocuring, or thermal curing.

10. The solid-state battery processing method of claim 1, wherein, The battery cell (100) is pressed by a preset pressure, and under the pressing of the preset pressure, the shrinkage rate of a plurality of protective layers is greater than or equal to the shrinkage rate of the battery cell (100).

11. The solid-state battery processing method of any one of claims 1-10, wherein, The protective layer does not protrude from the edge of the negative electrode sheet (110).

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