Preparation method of semi-solid cylindrical battery with high-porosity composite pole piece

Abstract

The invention provides a preparation method of a semi-solid cylindrical battery with high-porosity composite pole pieces, which comprises the following steps: A, according to the formula of positive and negative composite pole pieces, gluing a binder, sequentially adding a conductive agent, a solid electrolyte and positive and negative main materials into a stirring kettle, and uniformly stirring to respectively obtain positive and negative composite slurry; b, respectively coating and drying the positive and negative electrode paste to form positive and negative electrode composite pole pieces, and respectively rolling, slitting, cutting, welding tabs and winding the positive and negative electrode composite pole pieces to prepare a cylindrical battery cell; and C, injecting the in-situ curing electrolyte precursor into the cylindrical battery cell, standing for 1 minute under vacuum of-80kPa, standing for 12-48 hours in an environment of 20-35 DEG C after laser welding of a cap, and curing for 4-12 hours in a rotatable in-situ curing device at 60-80 DEG C to obtain the in-situ curing composite solid-state battery. And the cycle electrical performance of the solid-state battery can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a method for preparing a semi-solid cylindrical battery with a high-porosity composite pole piece. Background Art

[0002] Lithium-ion batteries are widely used in digital products and new energy vehicles due to their high energy density and low self-discharge characteristics. However, the energy density of traditional organic liquid electrolytes has reached a bottleneck, and in extreme cases, they are prone to fire and explosion accidents, limiting the commercial application of large-capacity and high-energy lithium secondary batteries. Therefore, it is crucial to improve the safety and electrochemical performance of lithium-ion batteries, especially to design and develop high-performance electrolytes.

[0003] Solid-state electrolytes have significant safety advantages over traditional organic electrolytes because they can reduce the flammable components in the battery. However, solid-state electrolytes also face problems such as large solid-solid interface impedance and low ionic conductivity, which affect the battery's charge and discharge performance and rate performance. Polymer solid electrolytes can significantly improve the safety and cycle performance of lithium-ion batteries due to their good flexibility and excellent interface contact properties. However, at room temperature, the low ionic conductivity of polymer solid electrolytes limits their industrial application.

[0004] In order to solve these problems, researchers usually use organic / inorganic composite solid electrolytes to improve the interface contact and ionic conductivity of solid-state batteries. However, due to the phase separation between ceramic fillers and polymers, the uneven penetration distribution of in-situ solidified electrolyte precursors in the low porosity inside cylindrical batteries, and the uneven heating during the in-situ curing process, the in-situ polymerization distribution is uneven, and large polymer blocks agglomerate, resulting in poor experimental repeatability of composite electrolytes and reduced electrochemical cycle performance. Therefore, it is necessary to develop a method for preparing in-situ polymerized solid cylindrical batteries based on high-porosity composite pole pieces. Summary of the invention

[0005] The present invention provides a method for preparing a semi-solid cylindrical battery with a high-porosity composite pole piece, so as to solve the problem of poor quality of battery preparation in the prior art and achieve the goal of greatly improving the cycle electrical performance of the solid-state battery.

[0006] The present invention provides a method for preparing a semi-solid cylindrical battery with a high-porosity composite pole piece, comprising the following steps:

[0007] A. According to the formula of the positive and negative composite electrode sheets, the binder is first glued, and then the conductive agent, solid electrolyte, positive electrode main material, and negative electrode main material are added to the stirring tank in sequence and stirred evenly to obtain positive and negative electrode composite slurries respectively;

[0008] B. The positive and negative electrode slurries are respectively coated and dried to form positive and negative electrode composite sheets, and the positive and negative electrode sheets are respectively rolled, slit, cut, tab welded, and wound to form cylindrical battery cells;

[0009] C. Then, the in-situ cured electrolyte precursor is injected into the cylindrical battery cell, allowed to stand for 1 minute under a vacuum of -80 kPa, and after laser welding the cap, allowed to stand for 1248 hours in an environment of 20-35°C, and cured in a rotatable in-situ curing device at 6080°C for 4-12 hours to obtain an in-situ cured composite solid-state battery.

[0010] Preferably, the main material of the positive electrode includes any one of lithium iron phosphate, lithium iron manganese phosphate, lithium manganese oxide, nickel-cobalt-manganese ternary, lithium-rich manganese base, lithium nickel manganese oxide, etc., or a combination of at least two; the main material of the negative electrode includes any one of graphite, nano-silicon, silicon-carbon negative electrode, silicon-oxygen negative electrode, tin-based negative electrode, lithium metal, etc., or a combination of at least two.

[0011] Preferably, the conductive agent includes any one of Supper Li P, carbon nanotubes, graphene, conductive graphite, VGCF, etc., or a combination of at least two thereof.

[0012] Preferably, the binder includes any one of PVDF, CMC, SBR, polyacrylic acid PAA, polytetrafluoroethylene PTFE, polyimide PI, etc., or a combination of at least two thereof.

[0013] Preferably, the solid electrolyte includes any one of Li(3x)La(2 / 3-x)TiO3, Li1+xAlxTi2-x(PO4)3 (x=0.2-0.5), Li7-xLa3Zr2-xMxO12 (M is one of the metal elements Nb / Ta / Y / Ca, x=0-2), and sulfur-LISICON, or a combination of at least two thereof.

[0014] Preferably, the in-situ solidified electrolyte precursor includes a polymerizable monomer, an initiator, a lithium salt, an inorganic filler, an inhibitor, a pore-forming agent, and an organic solvent. The mass percentage of the polymerizable monomer is 1%-40%, the mass percentage of the initiator to the mass percentage of the polymerizable monomer is 0.01%-3%, the mass percentage of the inorganic filler to the mass percentage of the polymerizable monomer is 0.0005%-10%, the mass percentage of the inhibitor to the mass percentage of the polymerizable monomer is 0.0005%-10%, the mass percentage of the organic solvent is 60%-90%, the mass percentage of the pore-forming agent is 0-10%, and the mass percentage of the additive is 2-10%.

[0015] Preferably, the polymerizable monomer includes any one of acrylic acid, methacrylic acid, methyl methacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, acrylonitrile, ethylene carbonate, ethylene oxide or 1,3-dioxolane or a combination of at least two thereof; the initiator includes any one of azobisisobutyronitrile, azobisisoheptylnitrile, azoisobutylcyanoformamide, dimethyl azobisisobutyrate, diisopropylbenzene peroxide or dibenzoyl peroxide or a combination of at least two thereof; the lithium salt includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(difluorosulfonyl imide), lithium bis(trifluoromethylsulfonyl imide), bis(oxalate)boron The inorganic filler comprises any one of Al2O3, TiO2, SiO2, ZrO2, Ta2O5 and La2O3 or a combination of at least two thereof; the polymerization inhibitor comprises any one of hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone, p-benzoquinone, methyl hydroquinone or tetrachlorobenzoquinone or a combination of at least two thereof; the pore-forming agent comprises any one of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium chloride, ammonium oxalate and the like or a combination of at least two thereof.

[0016] Preferably, the in-situ curing electrolyte precursor further includes an additive, and the additive includes any one of vinylene carbonate, fluoroethylene carbonate, cyclohexylbenzene, propylene sulfite, ethylene sulfate, fluorobenzene or sodium dodecyl sulfate, or a combination of at least two thereof.

[0017] Preferably, the in-situ curing device includes a base and a curing box, wherein the curing box is arranged above the base, a box cover is installed on the upper end of the curing box, a battery placement plate is installed in the inner cavity of the curing box, a plurality of placement slots are provided on the battery placement plate, and batteries to be cured are placed in the plurality of placement slots, a rotating motor is also installed inside the base, a motor shaft of the rotating motor is connected to one end of the rotating shaft, and the other end of the rotating shaft passes through the bottom end surface of the curing box and is connected to the middle part of the lower end surface of the battery placement plate, and a heating plate is also installed on the inner wall of the curing box.

[0018] Beneficial effects: The preparation method of the present invention is simple, wherein the nano-scale solid electrolyte added during the homogenization of the positive and negative electrodes can make the solid electrolyte evenly distributed in the electrode pieces in advance, and the addition of the pore-forming agent in the in-situ solidified electrolyte precursor generates pores during the in-situ solidification process, and the high porosity is conducive to the penetration of the in-situ solidified electrolyte precursor, making the in-situ solidification more uniform. At the same time, an in-situ solidification device is provided to mitigate the uneven distribution of the electrolyte and the uneven temperature distribution during the in-situ solidification process, so that the in-situ solidification is uniform to obtain a semi-solid battery with a uniform composite solid electrolyte, thereby greatly improving the various electrical properties of the solid-state battery.

[0019] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a flow chart of the preparation method of the present invention;

[0022] Figure 2 It is a schematic structural diagram of the in-situ curing device of the present invention;

[0023] Explanation of the reference numerals: base 1, curing box 2, box cover 3, battery placement plate 4, battery 5, rotating motor 6, rotating shaft 7, heating plate 8. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification, claims and accompanying drawings of the present invention are intended to cover non-exclusive inclusions.

[0026] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase "embodiments" in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, the "connection" or "connection" of a mechanical structure may refer to a physical connection. For example, the physical connection may be a fixed connection, such as a fixed connection through a fixing member, such as a fixed connection through a screw, bolt or other fixing member; the physical connection may also be a detachable connection, such as a mutual snap-on or snap-fit ​​connection; the physical connection may also be an integral connection, such as a connection formed by welding, bonding or integral molding. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0029] See also Figure 1 , Embodiment 1:

[0030] A method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode sheet, characterized in that it comprises the following steps:

[0031] A. According to the formula of the positive and negative composite electrode sheets, the binder is first glued, and then the conductive agent, solid electrolyte, positive electrode main material, and negative electrode main material are added to the stirring tank in sequence and stirred evenly to obtain positive and negative electrode composite slurries respectively;

[0032] B. The positive and negative electrode slurries are respectively coated and dried to form positive and negative electrode composite sheets, and the positive and negative electrode sheets are respectively rolled, slit, cut, tab welded, and wound to form cylindrical battery cells;

[0033] C. Then, the in-situ cured electrolyte precursor is injected into the cylindrical battery cell, allowed to stand for 1 minute under a vacuum of -80 kPa, and after laser welding the cap, allowed to stand for 12 hours in an environment of 20°C, and cured in a rotatable in-situ curing device at 60°C for 4 hours to obtain an in-situ cured composite solid-state battery.

[0034] In this embodiment, the main material of the positive electrode includes nickel, cobalt and manganese; the main material of the negative electrode includes a silicon-carbon negative electrode.

[0035] In this embodiment, the conductive agent includes a combination of Supper Li P and carbon nanotubes.

[0036] In this embodiment, the binder includes a combination of polytetrafluoroethylene PTFE and polyimide PI.

[0037] In this embodiment, the solid electrolyte includes lithium lanthanum zirconium oxide (modified) with a particle size of 100-300 nm.

[0038] In this embodiment, the in-situ solidified electrolyte precursor includes a polymerizable monomer, an initiator, a lithium salt, an inorganic filler, an inhibitor, a pore-forming agent, and an organic solvent. The mass percentage of the polymerizable monomer is 3%, the mass percentage of the initiator to the mass percentage of the polymerizable monomer is 3%, the mass percentage of the inorganic filler to the mass percentage of the polymerizable monomer is 1%, the mass percentage of the inhibitor to the mass percentage of the polymerizable monomer is 0.5%, the mass percentage of the pore-forming agent is 3%, and the mass percentage of the additive is 5%.

[0039] In this embodiment, the polymerization monomer includes a combination of acrylic acid and methacrylic acid; the initiator includes a combination of azobisisobutyronitrile and azobisisoheptylnitrile; the lithium salt includes lithium hexafluorophosphate and lithium tetrafluoroborate; the inorganic filler includes a combination of Al2O3 and TiO2; the inhibitor includes a combination of hydroquinone and p-hydroxyanisole; and the pore-forming agent includes ammonium oxalate.

[0040] In this embodiment, the in-situ solidified electrolyte precursor further includes an additive, and the additive includes a combination of vinylene carbonate and fluoroethylene carbonate.

[0041] Embodiment 2:

[0042] A method for preparing a semi-polymeric solid cylindrical battery with a high-porosity composite pole piece, characterized by comprising the following steps:

[0043] A. According to the formula of the positive and negative composite electrode sheets, the binder is first glued, and then the conductive agent, solid electrolyte, positive electrode main material, and negative electrode main material are added to the stirring tank in sequence and stirred evenly to obtain positive and negative electrode composite slurries respectively;

[0044] B. The positive and negative electrode slurries are respectively coated and dried to form positive and negative electrode composite sheets, and the positive and negative electrode sheets are respectively rolled, slit, cut, tab welded, and wound to form cylindrical battery cells;

[0045] C. Then, the in-situ cured electrolyte precursor is injected into the cylindrical battery cell, allowed to stand for 1 minute under a vacuum of -80 kPa, and after laser welding the cap, allowed to stand for 48 hours in a 35°C environment, and cured for 12 hours at 80°C in a rotatable in-situ curing device to obtain an in-situ cured composite solid-state battery.

[0046] In this embodiment, the main material of the positive electrode includes a combination of lithium iron phosphate and lithium iron manganese phosphate; the main material of the negative electrode includes graphite and nano-silicon.

[0047] In this embodiment, the conductive agent includes a combination of graphene and conductive graphite.

[0048] In this embodiment, the binder includes a combination of polyacrylic acid PAA and polytetrafluoroethylene PTFE.

[0049] In this embodiment, the solid electrolyte includes lithium lanthanum zirconium oxide (modified) with a particle size of 100-300 nm.

[0050] In this embodiment, the in-situ solidified electrolyte precursor includes a polymerizable monomer, an initiator, a lithium salt, an inorganic filler, an inhibitor, a pore-forming agent, and an organic solvent. The mass percentage of the polymerizable monomer is 3%, the mass percentage of the initiator to the mass percentage of the polymerizable monomer is 3%, the mass percentage of the inorganic filler to the mass percentage of the polymerizable monomer is 1%, the mass percentage of the inhibitor to the mass percentage of the polymerizable monomer is 0.5%, the mass percentage of the pore-forming agent is 3%, and the mass percentage of the additive is 5%.

[0051] In this embodiment, the polymerization monomer includes a combination of methyl methacrylate and pentaerythritol tetraacrylate; the initiator includes a combination of azoisobutylcyanamide and dimethyl azobisisobutyrate; the lithium salt includes lithium perchlorate and lithium hexafluoroarsenate; the inorganic filler includes a combination of SiO2 and ZrO2; the inhibitor includes a combination of 2,6-di-tert-butylparacresol and 2,5-di-tert-butylhydroquinone; and the pore-forming agent includes ammonium oxalate.

[0052] In this embodiment, the in-situ solidified electrolyte precursor further includes additives, and the additives include a combination of cyclohexylbenzene, propylene sulfite, and ethylene sulfate.

[0053] Embodiment three:

[0054] A method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode sheet, characterized in that it comprises the following steps:

[0055] A. According to the formula of the positive and negative composite electrode sheets, the binder is first glued, and then the conductive agent, solid electrolyte, positive electrode main material, and negative electrode main material are added to the stirring tank in sequence and stirred evenly to obtain positive and negative electrode composite slurries respectively;

[0056] B. The positive and negative electrode slurries are respectively coated and dried to form positive and negative electrode composite sheets, and the positive and negative electrode sheets are respectively rolled, slit, cut, tab welded, and wound to form cylindrical battery cells;

[0057] C. Then, the in-situ cured electrolyte precursor is injected into the cylindrical battery cell, allowed to stand for 1 minute under a vacuum of -80 kPa, and after laser welding the cap, allowed to stand for 14 hours in an environment of 22°C, and cured for 6 hours in a rotatable in-situ curing device at 65°C to obtain an in-situ cured composite solid-state battery.

[0058] In this embodiment, the main material of the positive electrode includes a nickel-cobalt-manganese ternary and a lithium-rich manganese-based combination; the main material of the negative electrode includes a silicon-carbon negative electrode and a silicon-oxygen negative electrode combination.

[0059] In this embodiment, the conductive agent includes a combination of graphene and conductive graphite.

[0060] In this embodiment, the binder includes a combination of PVDF, polyacrylic acid PAA, and polytetrafluoroethylene PTFE.

[0061] In this embodiment, the solid electrolyte includes lithium lanthanum zirconium oxide (modified) with a particle size of 100-300 nm.

[0062] In this embodiment, the in-situ solidified electrolyte precursor includes a polymerizable monomer, an initiator, a lithium salt, an inorganic filler, an inhibitor, a pore-forming agent, and an organic solvent. The mass percentage of the polymerizable monomer is 3%, the mass percentage of the initiator to the mass percentage of the polymerizable monomer is 3%, the mass percentage of the inorganic filler to the mass percentage of the polymerizable monomer is 1%, the mass percentage of the inhibitor to the mass percentage of the polymerizable monomer is 0.5%, the mass percentage of the pore-forming agent is 5%, and the mass percentage of the additive is 5%.

[0063] In this embodiment, the polymerization monomer includes a combination of methyl methacrylate, pentaerythritol tetraacrylate, and pentaerythritol triacrylate; the initiator includes a combination of azobisisobutyronitrile, azoisobutylcyanamide, and diisopropylbenzene peroxide; the lithium salt includes a combination of lithium hexafluorophosphate and lithium perchlorate; the inorganic filler includes a combination of Al2O3, TiO2, and Ta2O5; the inhibitor includes a combination of hydroquinone, 2-tert-butylhydroquinone, and benzoquinone; and the pore-forming agent includes ammonium oxalate.

[0064] In this embodiment, the in-situ solidified electrolyte precursor further includes an additive, and the additive includes a combination of vinylene carbonate, fluoroethylene carbonate, and fluorobenzene.

[0065] Embodiment 4:

[0066] A method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode sheet, characterized in that it comprises the following steps:

[0067] A. According to the formula of the positive and negative composite electrode sheets, the binder is first glued, and then the conductive agent, solid electrolyte, positive electrode main material, and negative electrode main material are added to the stirring tank in sequence and stirred evenly to obtain positive and negative electrode composite slurries respectively;

[0068] B. The positive and negative electrode slurries are respectively coated and dried to form positive and negative electrode composite sheets, and the positive and negative electrode sheets are respectively rolled, slit, cut, tab welded, and wound to form cylindrical battery cells;

[0069] C. Then, the in-situ cured electrolyte precursor is injected into the cylindrical battery cell, allowed to stand for 1 minute under a vacuum of -80 kPa, and after laser welding the cap, allowed to stand for 30 hours in a 30°C environment, and cured for 8 hours at 70°C in a rotatable in-situ curing device to obtain an in-situ cured composite solid-state battery.

[0070] In this embodiment, the main material of the positive electrode includes lithium iron phosphate, nickel-cobalt-manganese ternary, and lithium-rich manganese-based combination; the main material of the negative electrode includes graphite, nano-silicon, and silicon-carbon negative electrode combination.

[0071] In this embodiment, the conductive agent includes a combination of carbon nanotubes, graphene, and conductive graphite.

[0072] In this embodiment, the binder includes a combination of PVDF, polytetrafluoroethylene PTFE, and polyimide PI.

[0073] In this embodiment, the solid electrolyte includes lithium lanthanum zirconium oxide (modified) with a particle size of 100-300 nm.

[0074] In this embodiment, the in-situ solidified electrolyte precursor includes a polymerizable monomer, an initiator, a lithium salt, an inorganic filler, an inhibitor, a pore-forming agent, and an organic solvent. The mass percentage of the polymerizable monomer is 3%, the mass percentage of the initiator to the mass percentage of the polymerizable monomer is 3%, the mass percentage of the inorganic filler to the mass percentage of the polymerizable monomer is 1%, the mass percentage of the inhibitor to the mass percentage of the polymerizable monomer is 0.5%, the mass percentage of the pore-forming agent is 5%, and the mass percentage of the additive is 5%.

[0075] In this embodiment, the polymerization monomer includes a combination of acrylic acid, methacrylic acid, pentaerythritol tetraacrylate, and pentaerythritol triacrylate; the initiator includes a combination of azobisisobutyronitrile, azobisisoheptylnitrile, and azoisobutylcyanamide; the lithium salt includes a combination of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate; the inorganic filler includes a combination of Al2O3, TiO2, SiO2, and ZrO2; the inhibitor includes a combination of hydroquinone, p-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol; and the pore-forming agent includes ammonium oxalate.

[0076] In this embodiment, the in-situ solidified electrolyte precursor further includes an additive, and the additive includes a combination of vinylene carbonate, fluoroethylene carbonate, and ethylene sulfate.

[0077] In the present invention, the solid electrolyte is added in advance during the homogenization process of the positive and negative electrodes, so that the solid electrolyte can be evenly dispersed in the positive and negative electrode sheets. After the in-situ solidified electrolyte precursor is added and solidified, a more uniform composite solid electrolyte is formed, which can better solve the problem that the solid electrolyte is difficult to penetrate and infiltrate into the pores of the electrode sheets in the process where the solid electrolyte is dispersed in the electrolyte precursor.

[0078] In addition, the added pore-forming material generates gas when it is thermally decomposed during the in-situ curing process, and the evenly dispersed pore-forming agent particles form more pores during the in-situ polymerization process, which is beneficial to the penetration and infiltration of the in-situ curing electrolyte precursor, and is also beneficial to the uniform distribution of the liquid electrolyte. On the other hand, special pore-forming materials such as (ammonium oxalate) not only generate gas to form pores when they are thermally decomposed, but the generated oxalic acid is also beneficial to neutralize the residual alkali on the surface of the positive electrode material and the surface of the oxide solid electrolyte, reducing the generation of other side reactions during the cycle process, which can effectively improve the high-temperature performance of solid-state batteries.

[0079] See also Figure 2 The in-situ curing device includes a base 1 and a curing box 2, wherein the curing box 2 is arranged above the base 1, a box cover 3 is installed on the upper end of the curing box 2, a battery placement plate 4 is installed in the inner cavity of the curing box 2, a plurality of placement grooves are provided on the battery placement plate 4, and batteries 5 to be cured are placed in the plurality of placement grooves, a rotating motor 6 is also installed inside the base 1, a motor shaft of the rotating motor 6 is connected to one end of a rotating shaft 7, and the other end of the rotating shaft 7 passes through the bottom end surface of the curing box 2 and is connected to the middle part of the lower end surface of the battery placement plate 4, and a heating plate 8 is also installed on the inner wall of the curing box 2.

[0080] Experimental example:

[0081] The preparation of positive electrode sheet includes 97% positive electrode material, 1.5% conductive agent, and 1.5% PVDF binder by weight; the preparation of negative electrode sheet includes 96% positive electrode material, 1.5% conductive agent, and 2.5% CMC+PAA binder by weight.

[0082] In this embodiment, the main material of the positive electrode includes a nickel-cobalt-manganese ternary positive electrode, taking LiNi0.9Co0.5Mn0.5 as an example; the negative electrode includes a silicon-carbon material, taking a silicon-carbon negative electrode with a gram capacity of 450 as an example.

[0083] In this embodiment, the conductive agent is a composite conductive agent of SP and CNT, and single-arm carbon nanotubes are used on the silicon-carbon negative electrode side.

[0084] In this embodiment, a conventional cylindrical battery preparation method includes the following steps:

[0085] A. According to the formula of positive and negative electrode sheets, first glue the binder, then add the conductive agent and the main material in sequence into a stirring kettle and stir evenly to obtain positive and negative electrode slurries respectively;

[0086] B. The positive and negative electrode slurries are coated and dried into positive and negative electrode sheets according to the battery experimental design, and the positive and negative electrode sheets are respectively rolled, slit, cut, welded, and wound to form cylindrical battery cells;

[0087] C. Then inject 5.5g of ordinary high-nickel electrolyte into the cylindrical battery cell, seal it with laser welding after vacuum standing, and complete the production after cleaning, heat shrinking and coding. Let it stand in an environment of 45℃ for 12h, and then let it stand at room temperature for 24h.

[0088] In this embodiment, ordinary high-nickel electrolyte is used as an in-situ solidified electrolyte precursor to remove components such as polymerization monomers, initiators, inhibitors, and pore-forming agents, and other components are consistent.

[0089] The composite solid electrolytes prepared in various embodiments of the present invention were used for performance testing, and the data obtained are shown in the following table:

[0090]

[0091] In summary, the preparation method of the present invention is simple, wherein the nano-scale solid electrolyte added during the homogenization of the positive and negative electrodes can make the solid electrolyte evenly distributed in the electrode pieces in advance, and the addition of the pore-forming agent in the in-situ solidified electrolyte precursor generates pores during the in-situ solidification process, and the high porosity is conducive to the penetration of the in-situ solidified electrolyte precursor, making the in-situ solidification more uniform. At the same time, an in-situ solidification device is provided to mitigate the uneven distribution of the electrolyte and the uneven temperature distribution during the in-situ solidification process, so that the in-situ solidification is uniform to obtain a semi-solid battery with a uniform composite solid electrolyte, thereby greatly improving the various electrical properties of the solid-state battery.

[0092] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode, characterized in that: The following steps are involved: A. According to the formula of the positive and negative composite electrode sheets, the binder is first glued, and then the conductive agent, solid electrolyte, positive electrode main material, and negative electrode main material are added to the stirring tank in sequence and stirred evenly to obtain positive and negative electrode composite slurries respectively; B. The positive and negative electrode slurries are respectively coated and dried to form positive and negative electrode composite sheets, and the positive and negative electrode sheets are respectively rolled, slit, cut, tab welded, and wound to form cylindrical battery cells; C. Then, the in-situ cured electrolyte precursor is injected into the cylindrical battery cell, allowed to stand for 1 minute under a vacuum of -80 kPa, and after laser welding the cap, allowed to stand for 1248 hours in an environment of 20-35°C, and cured in a rotatable in-situ curing device at 6080°C for 4-12 hours to obtain an in-situ cured composite solid-state battery.

2. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 1, characterized in that: The main material of the positive electrode includes any one of lithium iron phosphate, lithium iron manganese phosphate, lithium manganese oxide, nickel-cobalt-manganese ternary, lithium-rich manganese base, lithium nickel manganese oxide, etc., or a combination of at least two; the main material of the negative electrode includes any one of graphite, nano-silicon, silicon-carbon negative electrode, silicon-oxygen negative electrode, tin-based negative electrode, lithium metal, etc., or a combination of at least two.

3. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 1, characterized in that: The conductive agent includes any one of Supper Li P, carbon nanotubes, graphene, conductive graphite, VGCF, etc., or a combination of at least two thereof.

4. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 1, characterized in that: The binder includes any one of PVDF, CMC, SBR, polyacrylic acid PAA, polytetrafluoroethylene PTFE, polyimide PI, etc., or a combination of at least two thereof.

5. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 1, characterized in that: The solid electrolyte includes any one of Li(3x)La(2 / 3-x)TiO3, Li1+xAlxTi2-x(PO4)3 (x=0.2-0.5), Li7-xLa3Zr2-xMxO12 (M is one of the Nb / Ta / Y / Ca metal elements, x=0-2), and sulfur-LISICON, or a combination of at least two thereof.

6. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 1, characterized in that: The in-situ solidified electrolyte precursor includes a polymerizable monomer, an initiator, a lithium salt, an inorganic filler, an inhibitor, a pore-forming agent, and an organic solvent. The mass percentage of the polymerizable monomer is 1%-40%, the mass percentage of the initiator to the mass percentage of the polymerizable monomer is 0.01%-3%, the mass percentage of the inorganic filler to the mass percentage of the polymerizable monomer is 0.0005%-10%, the mass percentage of the inhibitor to the mass percentage of the polymerizable monomer is 0.0005%-10%, the mass percentage of the organic solvent is 60%-90%, the mass percentage of the pore-forming agent is 0-10%, and the mass percentage of the additive is 2-10%.

7. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 6, characterized in that: The polymerizable monomer includes any one of acrylic acid, methacrylic acid, methyl methacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, acrylonitrile, ethylene carbonate, ethylene oxide or 1,3-dioxolane or a combination of at least two thereof; the initiator includes any one of azobisisobutyronitrile, azobisisoheptylnitrile, azoisobutylcyanoformamide, dimethyl azobisisobutyrate, diisopropylbenzene peroxide or dibenzoyl peroxide or a combination of at least two thereof; the lithium salt includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(difluorosulfonyl imide), lithium bis(trifluoromethylsulfonyl imide), lithium bis(oxalatoborate) , lithium difluorooxalatoborate or lithium bis(oxalate)borate, or a combination of at least two thereof; the inorganic filler includes any one of Al2O3, TiO2, SiO2, ZrO2, Ta2O5, and La2O3, or a combination of at least two thereof; the polymerization inhibitor includes any one of hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone, p-benzoquinone, methylhydroquinone, or tetrachlorobenzoquinone, or a combination of at least two thereof; the pore-forming agent includes any one of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium chloride, ammonium oxalate, or the like, or a combination of at least two thereof.

8. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 6, characterized in that: The in-situ solidified electrolyte precursor also includes an additive, and the additive includes any one of vinylene carbonate, fluoroethylene carbonate, cyclohexylbenzene, propylene sulfite, ethylene sulfate, fluorobenzene or sodium dodecyl sulfate, or a combination of at least two thereof.

9. The method for preparing a semi-solid cylindrical battery with a high-porosity composite electrode according to claim 1, characterized in that: The in-situ curing device comprises a base (1) and a curing box (2), wherein the curing box (2) is arranged above the base (1), a box cover (3) is installed at the upper end of the curing box (2), a battery placement plate (4) is installed in the inner cavity of the curing box (2), a plurality of placement slots are provided on the battery placement plate (4), and batteries (5) to be cured are placed in the plurality of placement slots, a rotating motor (6) is also installed inside the base (1), the motor shaft of the rotating motor (6) is connected to one end of a rotating shaft (7), and the other end of the rotating shaft (7) passes through the bottom end surface of the curing box (2) and is connected to the middle part of the lower end surface of the battery placement plate (4), and a heating plate (8) is also installed on the inner wall of the curing box (2).

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