Preparation method of solid-state battery cell and solid-state battery cell

Abstract

The present invention relates to a preparation method of a solid-state battery cell and a solid-state battery cell. The preparation method of the solid-state battery cell comprises: providing a prefabricated cell, the prefabricated cell comprising an aluminum-plastic film and a bare cell; performing a first injection process on the prefabricated cell, the substances injected in the first injection process comprising a monomer, an initiator and an electrolyte; performing a curing process on the prefabricated cell, so that the monomer is polymerized under the action of the initiator to form a gel electrolyte; the gel electrolyte wraps the bare cell; performing a first exhaust process on the aluminum-plastic film to discharge the by-products in the aluminum-plastic film; performing a second injection process on the prefabricated cell to inject a thick flame retardant into the aluminum-plastic film, the thick flame retardant is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with a fire-extinguishing microcapsule; performing a second exhaust process on the aluminum-plastic film to exhaust the air in the aluminum-plastic film. The method can improve the safety of the solid-state battery cell.

Description

Technical Field

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

[0002] In recent years, the rapid development of electric vehicles and energy storage industries has put forward higher requirements for the energy density, cost, cyclability and safety of secondary batteries. Traditional secondary batteries use liquid electrolytes, and there is a problem of battery thermal runaway during long-term use. In the process of battery thermal runaway, the flammable, easy to oxidize and highly chemically active characteristics of the electrolyte make it the key to the thermal runaway process. Thermal runaway causes include overcharging, external heating, internal short circuit and mechanical failure. During the charging and discharging process, a part of the lithium often cannot be embedded in the negative electrode, but is deposited on the surface of the negative electrode to form lithium dendrites. The growth of lithium dendrites pierces the diaphragm to cause an internal short circuit, and overheating begins. After that, the SEI film, diaphragm, electrolyte, and cathode materials successively decompose and release heat and oxygen, which promotes the further accumulation of heat, and finally reaches the combustion conditions of the electrolyte. The battery undergoes thermal runaway and eventually catches fire and explodes.

[0003] Solid-state batteries use solid electrolytes or semi-solid electrolytes to replace liquid electrolytes. Solid electrolytes or semi-solid electrolytes can be further subdivided into solid polymer electrolytes, gel polymer electrolytes, polyelectrolytes, composite polymer electrolytes and inorganic electrolytes. Solid electrolytes or semi-solid electrolytes can effectively avoid the leakage and volatilization of liquid electrolytes. However, due to various uncontrollable factors, solid-state batteries can still experience thermal runaway and cause battery fire and explosion. Therefore, it is necessary to further suppress thermal runaway to further improve the safety of the battery. Summary of the invention

[0004] Based on this, it is necessary to provide a method for preparing a solid-state battery cell and a solid-state battery cell to address the safety issues in the prior art.

[0005] In a first aspect, the present invention provides a method for preparing a solid-state battery cell, comprising:

[0006] Providing a prefabricated battery cell, wherein the prefabricated battery cell comprises an aluminum-plastic film and a bare battery cell;

[0007] Performing a first injection process on the prefabricated battery cell, wherein the substances injected in the first injection process include monomers, initiators and electrolytes;

[0008] The prefabricated battery cell is subjected to a curing process so that the monomer is polymerized under the action of the initiator to form a gel electrolyte; the gel electrolyte wraps the bare battery cell;

[0009] Performing a first exhaust process on the aluminum-plastic film to discharge byproducts in the aluminum-plastic film;

[0010] The prefabricated battery cell is subjected to a second injection process to inject a thick flame retardant into the aluminum-plastic film, wherein the thick flame retardant is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with fire extinguishing microcapsules;

[0011] The aluminum-plastic film is subjected to a second exhaust process to exhaust the air in the aluminum-plastic film.

[0012] The preparation method of the solid-state battery cell comprises: providing a prefabricated cell, the prefabricated cell comprising an aluminum-plastic film and a bare cell; performing a first injection process on the prefabricated cell, the substances injected in the first injection process comprising a monomer, an initiator and an electrolyte; performing a curing process on the prefabricated cell, so that the monomer is polymerized under the action of the initiator to form a gel electrolyte; the gel electrolyte wraps the bare cell; performing a first exhaust process on the aluminum-plastic film to discharge the byproducts in the aluminum-plastic film; performing a second injection process on the prefabricated cell, so as to inject a thick flame retardant into the aluminum-plastic film, the thick flame retardant is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with a fire extinguishing microcapsule; performing a second exhaust process on the aluminum-plastic film to exhaust the air in the aluminum-plastic film. The fire extinguishing microcapsules in the thick flame retardant can block the chain reaction of combustion, and the fire extinguishing microcapsules can also reduce the temperature and isolate oxygen to a certain extent, thereby improving the safety of the battery.

[0013] In some embodiments, the second injection process is performed on the prefabricated battery cell, comprising:

[0014] The angle between the prefabricated battery cell and the horizontal plane is set to 10° to 45°, and the prefabricated battery cell is subjected to a second injection process.

[0015] In some embodiments, the second exhaust process of the aluminum-plastic film includes:

[0016] The aluminum-plastic film is subjected to a second vacuuming process along the side of the aluminum-plastic film; the vacuuming force of the second vacuuming process is smaller than the vacuuming force of the first vacuuming process, and the vacuuming force of the second vacuuming process is smaller than the gravity of the viscous flame retardant.

[0017] In some embodiments, the prefabricated battery cell is provided, and the prefabricated battery cell includes an aluminum-plastic film and a bare battery cell, including:

[0018] Provide a diaphragm, multiple positive electrode sheets and multiple negative electrode sheets;

[0019] The separator, a plurality of positive electrode sheets, and a plurality of negative electrode sheets are stacked to obtain a prefabricated battery cell;

[0020] Providing an aluminum-plastic film, and forming a groove area on the aluminum-plastic film by a stamping process;

[0021] The prefabricated battery core is placed in the groove area and packaged with the aluminum-plastic film to obtain the prefabricated battery core.

[0022] In some embodiments, while punching out a groove area in the middle of the aluminum-plastic film using a stamping process, the method further includes:

[0023] At least one exhaust area is formed at the side of the groove area by a stamping process, and a gap is provided between the exhaust area and the groove area;

[0024] The first exhaust process is performed on the aluminum-plastic film to discharge the by-products in the aluminum-plastic film, including:

[0025] The aluminum-plastic film is cut along the interval between the exhaust area and the groove area, and a first exhaust process is performed on the aluminum-plastic film to exhaust byproducts in the aluminum-plastic film.

[0026] In some embodiments, the electrolyte additive includes at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, vinylene carbonate, fluorobenzene, methylene methanedisulfonate, fluoroethylene carbonate, vinyl sulfate, lithium difluorophosphate, and lithium bis(oxalatoborate).

[0027] In some embodiments, the shell of the fire extinguishing microcapsule comprises at least one of melamine, urea-formaldehyde resin, phenol-formaldehyde resin or melamine resin, and the core of the fire extinguishing microcapsule comprises at least one of perfluorohexanone, 2-bromo-3,3,3-trifluoropropene, dimethyl methyl phosphate, triester phosphate and tributyl phosphate.

[0028] In some embodiments, the monomer includes at least one of polyethylene glycol, ethylene glycol diacetate, pentaerythritol triacrylate, polyethylene glycol diacrylate, and ethoxylated trimethylolpropane triacrylate.

[0029] In some embodiments, the initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile, and azobisisoheptanenitrile.

[0030] In a second aspect, the present invention further provides a solid-state battery cell, comprising:

[0031] A bare cell, wherein the bare cell is formed by laminating a diaphragm, a plurality of positive electrode sheets, and a plurality of negative electrode sheets;

[0032] An aluminum-plastic film, the aluminum-plastic film comprising a groove area for accommodating the bare battery cell;

[0033] A gel electrolyte is located in the aluminum-plastic film and wraps the bare battery cell;

[0034] The thick flame retardant is located in the aluminum-plastic film and is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with fire extinguishing microcapsules.

[0035] The solid-state battery cell comprises a bare cell, which is formed by stacking a diaphragm, multiple positive electrode sheets, and multiple negative electrode sheets; an aluminum-plastic film, which includes a groove area for accommodating the bare cell; a gel electrolyte, which is located in the aluminum-plastic film and wraps the bare cell; a thick flame retardant, which is located in the aluminum-plastic film and contacts the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with a fire extinguishing microcapsule. The fire extinguishing microcapsules in the thick flame retardant can block the chain reaction of combustion, and the fire extinguishing microcapsules can also reduce the temperature and isolate oxygen to a certain extent, thereby improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. 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 these drawings without paying any creative work.

[0037] Figure 1 is a flow chart of a method for preparing a solid-state battery cell provided in an embodiment;

[0038] Figure 2 Schematic diagram of the structure of a solid-state battery cell provided in one embodiment.

[0039] Explanation of the reference numerals: 10 - aluminum-plastic film, 20 - bare battery cell, 201 - pole ear, 30 - gel electrolyte, 40 - viscous flame retardant. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0042] It should be understood that spatial relationship terms such as "under", "beneath", "below", "under", "over", "above", etc. may be used here to describe the relationship of one element or feature shown in the figures to other elements or features.

[0043] When used herein, the singular forms "a", "an" and " / the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0044] The "range" disclosed in the present invention is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The range defined in this way can be inclusive or exclusive of end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present invention, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0045] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0046] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0047] If not otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, a method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, a method further comprising step (c) indicates that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b, etc.

[0048] See also Figure 1 The present invention provides a method for preparing a solid-state battery cell, comprising the following steps:

[0049] S101: Provide prefabricated battery cells, including aluminum-plastic film and bare battery cells.

[0050] The aluminum-plastic film may be a sandwich structure, consisting of an outer resistance layer, a barrier layer and a heat-sealing layer. The material of the outer resistance layer may include nylon or polyethylene terephthalate, the material of the barrier layer may include aluminum foil, and the material of the heat-sealing layer may include polyethylene or polypropylene. The bare cell may be a multi-layer structure, consisting of a multi-layer positive electrode sheet, a separator and a multi-layer negative electrode sheet. The bare cell may also include a tab, a part of which is wrapped by the aluminum-plastic film, and the other part is exposed to connect to the external circuit. The aluminum-plastic film wraps the bare cell to protect the internal bare cell.

[0051] S102: performing a first injection process on the prefabricated battery cell, wherein the substances injected in the first injection process include monomers, initiators and electrolytes.

[0052] The top edge of the aluminum-plastic film can be sealed first, and one side of the aluminum-plastic film can be sealed at the same time, and the other side can be kept open, so that the first injection process can be performed from the other open side. Alternatively, the first injection process can be performed in other suitable ways, as long as the mixed solution composed of the monomer, the initiator and the electrolyte can be injected into the aluminum-plastic film, and this embodiment is not limited here.

[0053] Optionally, the monomer includes at least one of polyethylene glycol, ethylene glycol diacetate, pentaerythritol triacrylate, polyethylene glycol diacrylate, and ethoxylated trimethylolpropane triacrylate.

[0054] Optionally, the initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile and azobisisoheptylnitrile.

[0055] Optionally, the weight of the monomer is 1% to 10% of the weight of the electrolyte, and the weight of the initiator is 0.01% to 0.5% of the weight of the electrolyte.

[0056] S103: performing a curing process on the prefabricated battery cell, so that the monomer is polymerized under the action of an initiator to form a gel electrolyte; the gel electrolyte wraps the bare battery cell.

[0057] Among them, after the first injection process is completed, the open side of the aluminum-plastic film can be sealed first (that is, after the first injection process is completed and before the curing process, the prefabricated battery cell is completely sealed), and then the aluminum-plastic film is left to stand for a period of time so that the mixed solution composed of the monomer, initiator and electrolyte completely infiltrates the bare battery cell, and then begins to cure. The curing process specifically places the prefabricated battery cell under a constant pressure and a preset curing temperature for a period of time so that the mixed solution injected by the first injection process is finally cured into a gel electrolyte. Since the standing step has been carried out before curing, each layer of the bare battery cell can be fully infiltrated by the mixed solution. After the curing process, the gel electrolyte can wrap each layer of the bare battery cell, and the gel electrolyte can exist between each layer of the bare battery cell.

[0058] Optionally, the standing time may include 8 hours to 72 hours, the constant pressure used in the curing process may include 1000N to 3000N, and the preset curing temperature may include 50°C to 70°C.

[0059] S104: performing a first exhaust process on the aluminum-plastic film to discharge by-products in the aluminum-plastic film.

[0060] In the curing process, the ideal state is that the mixed solution will be converted into a gel electrolyte. However, in the actual production process, a part of the mixed solution may still not be cured, so there may be some excess liquid mixed solution in the by-product. In addition, some gaseous by-products may be formed during the curing process, so the by-products may contain both gaseous and liquid substances. The first exhaust process can usually be carried out in a vacuum environment. Therefore, in the first exhaust process, by controlling the size of the suction force, both gaseous and liquid by-products will be discharged, and the gel electrolyte will be retained.

[0061] S105: performing a second injection process on the prefabricated battery cell to inject a thick flame retardant into the aluminum-plastic film, wherein the thick flame retardant is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with a fire extinguishing microcapsule.

[0062] Among them, the thick flame retardant at least surrounds the gel electrolyte and contacts the gel electrolyte to achieve the purpose of flame retardancy. In order to make the thick flame retardant at least surround the gel electrolyte, the second injection process can be performed multiple times. For example, one side of the aluminum-plastic film can be cut, and the prefabricated battery cell is first injected with a part of the thick flame retardant by the second injection process. Then seal the side that has just been cut, and continue to cut the other side of the aluminum-plastic film, and inject part of the thick flame retardant into the prefabricated battery cell again by the second injection process, so that the thick flame retardant at least surrounds the gel electrolyte. Of course, in the actual process, the excess thick flame retardant may be transferred to other positions, but at least it should be ensured that the gel electrolyte is in contact with the thick flame retardant on all sides.

[0063] In addition, since the by-products produced in the curing process have been discharged during the first exhaust process, the aluminum-plastic film contains bare cells wrapped in gel electrolyte. At this time, cutting the side of the aluminum-plastic film will not cause the gel electrolyte to flow out like liquid electrolyte and cause loss.

[0064] Combustion requires four conditions, namely, combustibles (fuel), combustion aids (oxygen), ignition sources (referring to temperature or heat) and uninhibited chain reaction free radicals. The mechanism by which thick flame retardants prevent combustion is mainly through the action of the fire extinguishing microcapsules included in the thick flame retardants, which inhibit three of the four conditions for combustion, namely, combustion aids, ignition sources and chain reaction free radicals. Specifically, the fire extinguishing microcapsules are core-shell structures, the shell material is usually a polymer, and the core material is usually some flame retardants. When the bare battery cell accidentally burns, the shell of the fire extinguishing microcapsule will rupture first due to the heat, releasing the flame retardant in the core. The flame retardant can combine with the active free radicals generated during the flame combustion process to block the chain reaction of combustion, thereby playing a chemical inhibition and fire extinguishing function. In addition, the flame retardant in the core can be liquid. The liquid flame retardant will vaporize quickly when the temperature rises, and will also take away some of the temperature. The vaporized flame retardant may also cause the volume of the entire aluminum-plastic film to expand, so that the bare battery cells are protected by the vaporized flame retardant, thereby isolating oxygen and further playing a flame retardant role.

[0065] In addition, the fire extinguishing microcapsules are usually in powder form. Considering that it is difficult to evenly distribute them around the gel electrolyte if they are directly injected, the powdered fire extinguishing microcapsules are mixed with liquid electrolyte additives to obtain a viscous flame retardant, which can be easily injected.

[0066] Optionally, the electrolyte additive includes at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, vinylene carbonate, fluorobenzene, methylene disulfonate, fluoroethylene carbonate, vinyl sulfate, lithium difluorophosphate, and lithium bis(oxalatoborate).

[0067] Optionally, the shell of the fire extinguishing microcapsule includes at least one of melamine, urea-formaldehyde resin, phenol-formaldehyde resin or melamine resin, and the core of the fire extinguishing microcapsule includes at least one of perfluorohexanone, 2-bromo-3,3,3-trifluoropropylene, dimethyl methyl phosphate, triester phosphate and tributyl phosphate.

[0068] Optionally, the weight of the electrolyte additive is 1% to 5% of the weight of the mixed solution consisting of the monomer, the initiator and the electrolyte, and the weight of the fire extinguishing microcapsule is 1% to 5% of the weight of the mixed solution consisting of the monomer, the initiator and the electrolyte.

[0069] Optionally, the particle size of the fire extinguishing microcapsules may be micrometer-level or nanometer-level, for example, 100 nanometers to 500 micrometers.

[0070] Optionally, after the aluminum-plastic film is subjected to the first exhaust process and before the prefabricated battery cell is subjected to the second injection process, a formation and aging process may also be included. Furthermore, the temperature of the formation process may include 30°C to 50°C, and the clamp pressure of the formation process may include 1000N to 3000N. The formation process is a process of activating the positive and negative electrode materials inside the battery cell through low-rate charge and discharge to improve the battery's charge and discharge performance and comprehensive performance such as self-discharge and storage. It is also a process of SEI film formation.

[0071] S106: performing a second air extraction process on the aluminum-plastic film to extract the air in the aluminum-plastic film.

[0072] The second air extraction process is performed to maintain the air tightness of the aluminum-plastic film. After the second air extraction process, the aluminum-plastic film can be completely encapsulated to obtain a solid-state battery cell.

[0073] The above steps S102 and S104 to S106 can all be performed in a vacuum environment or an inert gas environment.

[0074] The preparation method of the solid-state battery cell comprises: providing a prefabricated cell, the prefabricated cell comprising an aluminum-plastic film and a bare cell; performing a first injection process on the prefabricated cell, the substances injected in the first injection process comprising monomers, initiators and electrolytes; performing a curing process on the prefabricated cell, so that the monomers are polymerized under the action of the initiator to form a gel electrolyte; the gel electrolyte wraps the bare cell; performing a first exhaust process on the aluminum-plastic film to discharge the by-products in the aluminum-plastic film; performing a second injection process on the prefabricated cell, so as to inject a thick flame retardant into the aluminum-plastic film, the thick flame retardant is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with a fire extinguishing microcapsule; performing a second exhaust process on the aluminum-plastic film to exhaust the air in the aluminum-plastic film. The fire extinguishing microcapsules in the thick flame retardant can block the chain reaction of combustion, and the fire extinguishing microcapsules can also reduce the temperature and isolate oxygen to a certain extent, thereby improving the safety of the battery.

[0075] In some embodiments, the above step S101 includes:

[0076] S1011: Provide a diaphragm, multiple positive electrode sheets, and multiple negative electrode sheets.

[0077] Among them, the positive electrode sheet and the negative electrode sheet are both finished products after rolling, slitting, die-cutting and other steps. The steps of preparing the positive electrode sheet and the negative electrode sheet are relatively conventional and are not limited here.

[0078] S1012: stacking a separator, a plurality of positive electrode sheets, and a plurality of negative electrode sheets to obtain a prefabricated battery cell.

[0079] S1013: providing an aluminum-plastic film, and forming a groove area on the aluminum-plastic film by a stamping process.

[0080] A groove area capable of accommodating the prefabricated battery cell can be punched out on the aluminum-plastic film using a forming mold at a preset stamping temperature. The number of groove areas can be one or two depending on the thickness of the prefabricated battery cell. For example, when the prefabricated battery cell is thin, one groove area can be punched out; and when the prefabricated battery cell is thick, two opposite groove areas can be punched out, and after the aluminum-plastic film is folded along the center line between the two groove areas, the two groove areas can overlap, so as to avoid deformation of the aluminum-plastic film during subsequent packaging due to the excessive thickness of the prefabricated battery cell.

[0081] S1014: placing the prefabricated battery cell in the groove area and encapsulating it with an aluminum-plastic film to obtain the prefabricated battery cell.

[0082] On the basis of the above embodiments, in some embodiments, while executing step S1013, the method for preparing a solid-state battery cell further includes: forming at least one exhaust area on the side of the groove area by a stamping process, and a gap is provided between the exhaust area and the groove area. The above step S104 further includes: cutting the aluminum-plastic film along the gap between the exhaust area and the groove area, and performing a first exhaust process on the aluminum-plastic film to discharge byproducts in the aluminum-plastic film.

[0083] The area of ​​the exhaust area can be smaller than the area of ​​the groove area, the number of exhaust areas can be determined according to the actual production process, and the specific location of the exhaust area can also be determined according to the actual production process, which is not limited in this embodiment. The exhaust area is used to temporarily store the by-product gas generated in the curing process, and the exhaust area can effectively prevent the deformation of the aluminum-plastic film caused by excessive by-product gas formed in the curing process.

[0084] Furthermore, in step S104, after the byproducts of the aluminum-plastic film are discharged, the second injection process of step S105 can be directly continued based on the cut side of the aluminum-plastic film, so that the aluminum-plastic film does not need to be repackaged, and because the process of cutting the aluminum-plastic film can usually be performed in a vacuum or inert gas environment, and the second injection process usually needs to be performed in a vacuum or inert gas environment, there is no need to transfer the aluminum-plastic film. That is, after cutting off the exhaust area, the first exhaust process and the second injection process can be completed simultaneously in the same vacuum or inert gas environment, thereby saving process steps and reducing process costs.

[0085] In some embodiments, the above step S105 includes: setting the angle between the prefabricated battery cell and the horizontal plane to 10°~45°, and performing a second injection process on the prefabricated battery cell. That is, it is equivalent to keeping the prefabricated battery cell tilted, so that the thick flame retardant can continue to extend a distance into the aluminum-plastic film by its own gravity after injection, so that the thick flame retardant can be distributed to a more ideal position. In particular, battery cell fires usually occur near the pole ear, and the interval between the top edge of the aluminum-plastic film and the bare battery cell is close. If the parallel placement method of the conventional injection process is used, the thick flame retardant will be difficult to enter the interval between the top edge of the aluminum-plastic film and the bare battery cell, and it is even more difficult to fully contact the gel electrolyte near the pole ear. In this embodiment, by setting the angle between the prefabricated battery cell and the horizontal plane to 10°~45°, due to gravity, the thick flame retardant can maintain more sufficient contact with the gel electrolyte near the pole ear, which is more conducive to improving the safety of the battery cell.

[0086] Based on the above embodiments, in some embodiments, the above step S106 includes: performing a second vacuuming process on the aluminum-plastic film along the side of the aluminum-plastic film; the vacuuming force of the second vacuuming process is less than the vacuuming force of the first vacuuming process, and the vacuuming force of the second vacuuming process is less than the gravity of the viscous flame retardant.

[0087] In this embodiment, since the first air extraction process needs to discharge byproducts as much as possible, the suction force of the first air extraction process is relatively large. In the second air extraction process, there are basically no byproducts in the aluminum-plastic film, and only the excess air in the aluminum-plastic film needs to be extracted to ensure the air tightness of the aluminum-plastic film. Therefore, the suction force of the second air extraction process can be smaller than the suction force of the first air extraction process. At the same time, in order to prevent the thick flame retardant from being extracted, and since the aluminum-plastic film is still tilted, the suction force of the second air extraction process also needs to be smaller than the gravity of the thick flame retardant.

[0088] The present invention also provides a solid-state battery cell, comprising: a bare cell 20, which is formed by stacking a diaphragm, multiple positive electrode sheets, and multiple negative electrode sheets; an aluminum-plastic film 10, which includes a groove area for accommodating the bare cell 20; a gel electrolyte 30, which is located in the aluminum-plastic film 10 and wraps the bare cell 20; a viscous flame retardant 40, which is located in the aluminum-plastic film 10 and contacts with the gel electrolyte 30; the viscous flame retardant 40 is formed by mixing an electrolyte additive with a fire-extinguishing microcapsule.

[0089] like Figure 2 As shown, the aluminum-plastic film 10 may be a sandwich structure, consisting of an outer resistance layer, a barrier layer and a heat-sealing layer. The material of the outer resistance layer may include at least one of nylon or polyethylene terephthalate, the material of the barrier layer may include aluminum foil, and the material of the heat-sealing layer may include at least one of polyethylene or polypropylene. The bare battery cell 20 may be a multi-layer structure, consisting of a multi-layer positive electrode sheet, a separator and a multi-layer negative electrode sheet. The bare battery cell 20 may also include a tab 201, a portion of which is wrapped by the aluminum-plastic film 10, and the other portion is exposed to connect to an external circuit. The aluminum-plastic film 10 wraps the bare battery cell 20, which can protect the internal bare battery cell 20.

[0090] Among them, the gel electrolyte 30 is prepared by curing a mixed solution consisting of a monomer, an initiator and an electrolyte under appropriate curing conditions. Optionally, the monomer includes at least one of polyethylene glycol, ethylene glycol diacetate, pentaerythritol triacrylate, polyethylene glycol diacrylate, and ethoxylated trimethylolpropane triacrylate. Optionally, the initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile, and azobisisoheptonitrile. Optionally, the weight of the monomer is 1% to 10% of the weight of the electrolyte, and the weight of the initiator is 0.01% to 0.5% of the weight of the electrolyte.

[0091] The thick flame retardant 40 at least surrounds the gel electrolyte 30 and contacts the gel electrolyte 30 to achieve the purpose of flame retardancy. This is because combustion requires four conditions, namely, combustibles (fuel), combustion aids (oxygen), ignition sources (referring to temperature or heat) and uninhibited chain reaction free radicals. The mechanism by which the thick flame retardant 40 prevents combustion is mainly through the action of the fire extinguishing microcapsules included in the thick flame retardant 40, which inhibits three of the four combustion conditions, namely, combustion aids, ignition sources and chain reaction free radicals. Specifically: the fire extinguishing microcapsule is a core-shell structure, the material of its shell is usually a polymer, and the material of the core is usually some flame retardant. When the bare battery cell 20 accidentally burns, the shell of the fire extinguishing microcapsule is the first to rupture due to heat, releasing the flame retardant in the core. The flame retardant can combine with the active free radicals generated during the flame combustion process to block the chain reaction of combustion, thereby playing a chemical inhibition and fire extinguishing function. In addition, the flame retardant in the inner core may be in liquid form, and the liquid flame retardant will vaporize rapidly when the temperature rises, taking away part of the temperature; the vaporized flame retardant may also cause the volume of the entire aluminum-plastic film 10 to expand, so that the bare battery cells 20 are all protected by the vaporized flame retardant, thereby isolating oxygen and further playing a flame retardant role.

[0092] Optionally, the electrolyte additive includes at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, vinylene carbonate, fluorobenzene, methylene disulfonate, fluoroethylene carbonate, vinyl sulfate, lithium difluorophosphate, and lithium bis(oxalatoborate).

[0093] Optionally, the shell of the fire extinguishing microcapsule includes at least one of melamine, urea-formaldehyde resin, phenol-formaldehyde resin or melamine resin, and the core of the fire extinguishing microcapsule includes at least one of perfluorohexanone, 2-bromo-3,3,3-trifluoropropylene, dimethyl methyl phosphate, triester phosphate and tributyl phosphate.

[0094] Optionally, the weight of the electrolyte additive is 1% to 5% of the weight of the mixed solution consisting of the monomer, the initiator and the electrolyte, and the weight of the fire extinguishing microcapsule is 1% to 5% of the weight of the mixed solution consisting of the monomer, the initiator and the electrolyte.

[0095] Optionally, the particle size of the fire extinguishing microcapsules can be micrometer-level or nanometer-level, for example, 100 nanometers to 500 micrometers.

[0096] Optionally, the solid-state battery cell may be prepared by the method for preparing a solid-state battery cell in any of the above embodiments.

[0097] also, Figure 2This is only for the purpose of showing the relative positional relationship of the various parts of the solid-state battery cell. The specific solid-state battery cell structure should still be based on the textual description in the present invention and the actual product produced. For example, especially for the relative positional relationship between the gel electrolyte and the bare cell, although Figure 2 The gel electrolyte 30 seems to only wrap around the bare cell 20 . However, it should be noted that in the actual structure of the solid-state battery cell, the gel electrolyte 30 can wrap each layer of the bare cell 20 , and the gel electrolyte 30 can exist between each layer of the bare cell 20 .

[0098] The solid-state battery cell comprises a bare cell 20, which is formed by laminating a diaphragm, multiple positive electrode sheets, and multiple negative electrode sheets; an aluminum-plastic film 10, which includes a groove area for accommodating the bare cell 20; a gel electrolyte 30, which is located in the aluminum-plastic film 10 and wraps the bare cell 20; a thick flame retardant 40, which is located in the aluminum-plastic film 10 and contacts the gel electrolyte 30; the thick flame retardant 40 is formed by mixing an electrolyte additive with a fire extinguishing microcapsule. The fire extinguishing microcapsules in the thick flame retardant 40 can block the chain reaction of combustion, and the fire extinguishing microcapsules can also reduce the temperature and isolate oxygen to a certain extent, thereby improving the safety of the battery.

[0099] The present invention also provides a solid-state battery, which includes the solid-state battery cell in any of the above embodiments.

[0100] The present invention also provides an electric device, which includes the solid-state battery in any of the above embodiments. The electric device may include various devices using batteries, such as electric vehicles, electric toys, electric tools, ships, spacecraft, etc.; spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0101] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a solid-state battery cell, characterized in that: include: Providing a prefabricated battery cell, wherein the prefabricated battery cell comprises an aluminum-plastic film and a bare battery cell; Performing a first injection process on the prefabricated battery cell, wherein the substances injected in the first injection process include monomers, initiators and electrolytes; The prefabricated battery cell is subjected to a curing process so that the monomer is polymerized under the action of the initiator to form a gel electrolyte; the gel electrolyte wraps the bare battery cell; Performing a first exhaust process on the aluminum-plastic film to discharge byproducts in the aluminum-plastic film; The angle between the prefabricated battery core and the horizontal plane is set to 10° to 45°, and the prefabricated battery core is subjected to a second injection process to inject a thick flame retardant into the aluminum-plastic film, wherein the thick flame retardant is in contact with the gel electrolyte; the thick flame retardant is formed by mixing a liquid electrolyte additive with a fire extinguishing microcapsule; Performing a second air extraction process on the aluminum-plastic film to extract air from the aluminum-plastic film; When the bare battery core burns, the shell of the fire-extinguishing microcapsule ruptures due to heat, releasing the flame retardant in the inner core.

2. The method for preparing a solid-state battery cell according to claim 1, characterized in that: The second exhaust process of the aluminum-plastic film includes: A second vacuuming process is performed on the aluminum-plastic film along the side of the aluminum-plastic film; the vacuuming force of the second vacuuming process is smaller than the vacuuming force of the first vacuuming process, and the vacuuming force of the second vacuuming process is smaller than the gravity of the viscous flame retardant.

3. The method for preparing a solid-state battery cell according to claim 1, characterized in that: The prefabricated battery cell is provided, and the prefabricated battery cell includes an aluminum-plastic film and a bare battery cell, including: Provide a diaphragm, multiple positive electrode sheets and multiple negative electrode sheets; The separator, a plurality of positive electrode sheets, and a plurality of negative electrode sheets are stacked to obtain a prefabricated battery cell; Providing an aluminum-plastic film, and forming a groove area on the aluminum-plastic film by a stamping process; The prefabricated battery core is placed in the groove area and packaged with the aluminum-plastic film to obtain the prefabricated battery core.

4. The method for preparing a solid-state battery cell according to claim 3, characterized in that: While the punching process is used to punch out a groove area in the middle of the aluminum-plastic film, the method further comprises: At least one exhaust area is formed at the side of the groove area by a stamping process, and a gap is provided between the exhaust area and the groove area; The first exhaust process is performed on the aluminum-plastic film to discharge the by-products in the aluminum-plastic film, including: The aluminum-plastic film is cut along the interval between the exhaust area and the groove area, and a first exhaust process is performed on the aluminum-plastic film to exhaust byproducts in the aluminum-plastic film.

5. The method for preparing a solid-state battery cell according to claim 1, characterized in that: The electrolyte additive includes at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, vinylene carbonate, fluorobenzene, methylene methanedisulfonate, fluoroethylene carbonate, vinyl sulfate, lithium difluorophosphate, and lithium bis(oxalatoborate).

6. The method for preparing a solid-state battery cell according to claim 1, characterized in that: The shell of the fire extinguishing microcapsule comprises at least one of melamine, urea-formaldehyde resin, phenol-formaldehyde resin or melamine resin, and the core of the fire extinguishing microcapsule comprises at least one of perfluorohexanone, 2-bromo-3,3,3-trifluoropropylene, dimethyl methyl phosphate, triester phosphate and tributyl phosphate.

7. The method for preparing a solid-state battery cell according to claim 1, characterized in that: The monomer includes at least one of polyethylene glycol, ethylene glycol diacetate, pentaerythritol triacrylate, polyethylene glycol diacrylate, and ethoxylated trimethylolpropane triacrylate.

8. The method for preparing a solid-state battery cell according to claim 1, characterized in that: The initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile and azobisisoheptylnitrile.

9. A solid-state battery cell, characterized in that: The solid-state battery cell is prepared by the method for preparing a solid-state battery cell according to any one of claims 1 to 8, and the solid-state battery cell comprises: A bare cell, wherein the bare cell is formed by laminating a diaphragm, a plurality of positive electrode sheets, and a plurality of negative electrode sheets; An aluminum-plastic film, the aluminum-plastic film comprising a groove area for accommodating the bare battery cell; A gel electrolyte is located in the aluminum-plastic film and wraps the bare battery cell; The thick flame retardant is located in the aluminum-plastic film and is in contact with the gel electrolyte; the thick flame retardant is formed by mixing an electrolyte additive with fire extinguishing microcapsules.

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