Manufacturing method of in-situ polymerized semi-solid battery

Abstract

To provide a manufacturing method of a site polymerization type semi-solid battery.SOLUTION: A manufacturing method of a site polymerization type semi-solid battery, contains: an assembling step of assembling a positive electrode plate, a separator, and a negative electrode plate to a case and forms a dry battery cell; a primary liquid implantation step of implanting a liquid-like electrolyte of a lithium battery; an aging and formation step; a secondary liquid implantation step of implanting a mixture of a polymer monomer, a plasticizer, and an initiator, and obtaining the polymer monomer of a combination of vinylene carbonate and tripropargyl phosphate; and an aging step of obtaining the semi-solid battery by performing gelatization by the site polymer under 58°C to 65°C.EFFECT: Since a spatial configuration monomer is contained in a secondary implantation processing, the liquid-like electrolyte may be locked to the spatial configuration after cross-linkage. By comparing it with a chain-like polymer, the semi-solid battery of which an effect of a gel can be obtained with less polymer, a gel construction to be formed is more stable, a thermal stable is excellent, a liquid amount is large, and an impedance is low can be obtained.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of semi-solid batteries, and in particular to a method for manufacturing in situ polymerized semi-solid batteries. [Background technology]

[0002] As the demand for improved energy density of lithium-ion batteries increases, conventional lithium-ion batteries have difficulty meeting the demand for ultra-high specific energy. Currently, the anode materials for commercially available lithium-ion batteries are mainly modified natural graphite and artificial graphite. Despite mature manufacturing technology, the theoretical specific capacity of graphite is 372 mAh g. -1 However, these are only low enough to meet the market demand for high-energy density lithium-ion batteries, making it difficult to meet the market demand for high-energy density batteries. Therefore, the demand for high-energy density batteries has led to a boom in the study of anode materials with the advantage of ultra-high specific energy. Examples include silicon anodes, metal alloy anodes, and metallic lithium anodes. For silicon anode materials, the goal of improving specific capacity is currently achieved mainly by blending a certain amount of silicon material. For metallic lithium anodes, the specific capacity is 3860 mAh·g. -1 and the electrochemical potential is -3.04 V (vs. standard hydrogen electrode). Batteries fabricated with these anode materials effectively increase the energy density to 400 Wh kg -1 Among them, high-nickel ternary lithium batteries have high activity, and when used in combination with high-specific-capacity anode materials, they not only improve the specific energy density but also contribute to improving battery safety.

[0003] However, in the current lithium-ion battery system, high-energy density battery materials currently have many potential safety risks, such as large volume expansion and structural changes of the material itself, and potential risks to cycle life and safety when used in combination with a liquid electrolyte. Liquid electrolytes cannot effectively suppress the extremely large expansion of the silicon negative electrode, the structural changes of the lithium metal negative electrode, and the growth of metal dendrites. Furthermore, the dendrites can pierce the separator, causing a short circuit inside the battery, which poses a more serious safety issue.

[0004] In-situ polymerization semi-solid-state batteries effectively reduce the amount of liquid electrolyte used, improving the battery's energy density while simultaneously reducing potential safety risks associated with liquid electrolytes. Furthermore, semi-solid gel electrolytes can effectively inhibit structural changes in the anode and the growth of metal dendrites to some extent, improving specific energy and significantly improving battery safety. However, the electrolyte formulation and manufacturing method of semi-solid-state batteries have a significant impact on battery impedance. In particular, the conventional in-situ polymerization method results in the polymer being involved in the formation of the anode SEI coating, significantly increasing battery impedance. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a method for manufacturing an in-situ polymerized semi-solid battery. By using a suitable electrolyte formulation and amount, and a special manufacturing process, the impedance of the semi-solid battery can be reduced, the energy density of the battery can be increased, and the safety of the battery can be significantly improved. [Means for solving the problem]

[0006] The object of the present invention is achieved by the following technical means.

[0007] The present invention provides An assembly step (S1) of assembling a positive electrode plate, a separator, and a negative electrode plate into a case to form a dry battery cell; A primary liquid injection step (S2) of injecting a liquid electrolyte for the lithium battery; an aging and formation step (S3); a secondary liquid injection step (S4) of injecting a mixture of a polymer monomer, a plasticizer, and an initiator, wherein the polymer monomer is a combination of vinylene carbonate and tripropargyl phosphate; and an aging step (S5) of gelling the mixture by in situ polymerization to obtain a semi-solid battery.

[0008] In one embodiment, the total amount of secondary injection is 5 wt.%-30 wt.% of the total amount of primary injection, preferably 10 wt.%-20 wt.%, for example, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, or 19 wt.%, and more preferably 10 wt.%-15 wt.%. In the present invention, the total amount of primary injection is the mass of the lithium battery liquid electrolyte injected into the battery cell during primary injection, and the total amount of secondary injection is the total mass of the polymer monomer, plasticizer, and initiator injected into the battery cell during secondary injection.

[0009] In one embodiment, the polymer monomer accounts for 70 wt.%-95 wt.% (e.g., 70 wt.%, 72 wt.%, 74 wt.%, 74.9 wt.%, 76 wt.%, 78 wt.%, 80 wt.%, 82 wt.%, 84 wt.%, 86 wt.%, 88 wt.%, 90 wt.%, 92 wt.%, 94 wt.%, 95 wt.%, etc.) of the total amount of secondary liquid injection, preferably 80 wt.%-90 wt.%. The plasticizer accounts for 4.8wt.%-29.8wt.% of the total secondary liquid injection (e.g., 4.8wt.%, 5.9wt.%, 7wt.%, 10wt.%, 13wt.%, 15wt.%, 17wt.%, 20wt.%, 22wt.%, 25wt.%, 27wt.%, 29wt.%, 29.8wt.%, etc.). The initiator accounts for 0.01 wt.%-0.4 wt.% (e.g., 0.01 wt.%, 0.05 wt.%, 0.1 wt.%, 0.15 wt.%, 0.2 wt.%, 0.25 wt.%, 0.3 wt.%, 0.35 wt.%, 0.4 wt.%, etc.) of the total amount of the secondary liquid injection, preferably 0.05 wt.%-0.1 wt.%.

[0010] In one embodiment, the weight ratio of vinylene carbonate (VC) to tripropargyl phosphate (TPP) in the polymer monomers is 10:1-100:1, preferably 20:1-50:1, for example, 30:1 or 40:1. VC is the main polymer monomer, and TPP is the auxiliary polymer monomer. TPP contains a phosphate structure, which can reduce the impedance of the semi-solid electrolyte. If the VC content is too high, the battery impedance will be significantly improved. However, if the VC content is too low, the electrolyte will not gel easily, and the semi-solid electrolyte will not be effectively formed.

[0011] In some embodiments, the plasticizer comprises one or more selected from tetraethyl silicate, epoxy-grafted cage epoxy polyhedral oligomeric silsesquioxane, boric acid, and silicon tetrachloride.

[0012] In one embodiment, the plasticizer is one or more selected from tetraethyl silicate (TEOS), epoxy-grafted cage-type epoxy polyhedral oligomeric silsesquioxane (EP-POSS), boric acid (BA), and silicon tetrachloride (SiCl4). The plasticizer is preferably epoxy-grafted cage-type epoxy polyhedral oligomeric silsesquioxane (EP-POSS). EP-POSS has a cage-like structure, which locks the liquid electrolyte within the cage-like structure, inhibiting the flow of the liquid electrolyte and improving safety performance.

[0013] In some embodiments, the initiator comprises one or more selected from 2,2-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyrate) dimethyl, and dibenzoyl peroxide.

[0014] In one embodiment, the initiator is one or more selected from 2,2-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyrate) dimethyl, and dibenzoyl peroxide (BPO). In some embodiments, the initiator is AIBN or BPO.

[0015] In one embodiment, in step S3, the aging temperature is 20°C-50°C and the aging time is 22h-26h, preferably the aging temperature is 45°C-48°C and the aging time is 24h.

[0016] In one embodiment, in step S3, the formation temperature is 40±5° C., and the formation pressure is 2000N-4000N, for example, 2500N, 3000N, or 3500N.

[0017] In one embodiment, in step S5, the aging temperature is 20°C-50°C and the aging time is 22h-26h. Preferably, the aging temperature is 45°C-48°C and the aging time is 24h. In some embodiments, in step S5, the aging temperature is 25±5°C and the aging time is 24±2h.

[0018] In some embodiments, in step S5, gelation occurs by in situ polymerization at 58°C-65°C.

[0019] In some embodiments, in step S5, the in-situ polymerization temperature is 60±2°C.

[0020] In one embodiment, in step S5, the in-situ polymerization time is 1.25 h-3 h, for example, 1.5 h, 2 h, 2.5 h.

[0021] In some embodiments, in step S2, the liquid electrolyte of the lithium battery includes a lithium salt, a solvent, and an additive.

[0022] In some embodiments, the lithium salt in the liquid electrolyte of the lithium battery comprises one or more selected from lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, and lithium difluorobis(oxalato)phosphate.

[0023] In one embodiment, in step S2, the lithium salt of the liquid electrolyte of the lithium battery is one or more selected from lithium hexafluorophosphate (LiPF), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiCFSO), lithium tetrafluoroborate (LiBF), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiODFB), and lithium difluorobis(oxalato)phosphate (LiDFBP). In some embodiments, the lithium salt includes lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide. The mass percentage of the lithium salt in the liquid electrolyte of the lithium battery may be 5 wt.%-30 wt.%, for example, 10 wt.%, 15 wt.%, 20 wt.%, 23 wt.%, 25 wt.%, 27 wt.%.

[0024] In some embodiments, in step S2, the solvent is one or more selected from ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate, dimethyl carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, and butyl propionate. In some embodiments, the solvent includes EC, EMC, and DEC. The mass percentage of the solvent in the liquid electrolyte of the lithium battery may be 60 wt.%-90 wt.%, for example, 65 wt.%, 70 wt.%, 75 wt.%, 80 wt.%, or 85 wt.%.

[0025] In some embodiments, in step S2, the additive is one or more selected from lithium difluorophosphate (LiPOF), fluoroethylene carbonate (FEC), ethylene sulfate (DTD), vinylene carbonate, vinylethylene carbonate, 1,3-propane sultone, 1-propene-1,3-sultone, tris(trimethylsilyl)phosphite, tris(trimethylsilyl)borate, lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, lithium tetrafluoroborate, and lithium difluoro(oxalato)phosphate. In some embodiments, the additive includes LiPOF, FEC, and DTD. The mass percentage of the additive in the liquid electrolyte of the lithium battery may be 2 wt.%-10 wt.%, for example, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, or 9 wt.%.

[0026] In one embodiment, the negative electrode plate employs a silicon-doped graphite negative electrode, a lithium metal negative electrode, or a metal alloy negative electrode, and the silicon content of the silicon-doped graphite negative electrode is 3 wt.%-80 wt.%, for example, 4 wt.%, 5 wt.%, 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, 50 wt.%, or 60 wt.%, preferably 5 wt.%-60 wt.%, and more preferably 8 wt.%-30 wt.%. The metal alloy negative electrode includes a Ga-Sn, Ge-Se, or Sn-Al alloy negative electrode. The negative electrode material of the silicon-doped graphite negative electrode includes graphite and a silicon-containing material. In some embodiments, the negative electrode material of the silicon-doped graphite negative electrode is graphite and a silicon-containing material. The amount of silicon added in the silicon-added graphite negative electrode is the mass part of the silicon-containing material in the negative electrode material in the silicon-added graphite negative electrode. The silicon-containing material may contain at least one material selected from a silicon-oxygen material and a silicon-carbon material.

[0027] In one embodiment, the positive plate material (positive electrode material) is a high-nickel material (NCM811, Ni90), NCM111, NCM532, NCM622, NCM712, nickel-cobalt-aluminum material (NCA), lithium manganese iron phosphate (LMFP), or lithium iron (II) phosphate (LiFePO4). x Co y Mn z O2, where x≧0.8. In some embodiments, Ni90 has the structural formula LiNi x Co y Mn z In O2, x≧0.8, y≧0, z≧0, and x+y+z=1. In some embodiments, Ni90 has the structural formula LiNi x Co y Mn z In O2, x≧0.9, y≧0, z≧0, and x+y+z=1. NCM811, NCM111, NCM532, NCM622, and NCM712 represent nickel-cobalt-manganese ternary positive electrode materials with molar ratios of Ni atoms to Co atoms to Mn atoms of 8:1:1, 1:1:1, 5:3:2, 6:2:2, and 7:1:2, respectively.

[0028] In one embodiment, the positive and negative electrode plates contain a conductive agent, specifically, the conductive agent is one or more selected from carbon black (super P), acetylene black, multi-walled carbon nanotubes (MWCNT), and single-walled carbon nanotubes (SWCNT).

[0029] In one embodiment, the positive and negative electrode plates include an adhesive, specifically, the adhesive is one or more selected from PEO (polyethylene oxide), PVDF (polyvinylidene fluoride), CMC (sodium carboxymethyl cellulose), PU (polyurethane), SBR (styrene butadiene rubber), PVA (polyvinyl alcohol), PAA (polyacrylic acid), and PAN (polyacrylonitrile). [Effects of the Invention]

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1) This invention adopts the technology of in-situ polymerization to fabricate / produce semi-solid batteries, by first injecting a general liquid electrolyte and forming it, and then injecting a polymer monomer and polymerizing it in-situ, which results in a semi-solid battery with low impedance.

[0032] 2) The secondary liquid injection formulation contains tripropargyl phosphate (TPP), a three-dimensional monomer, which allows the liquid electrolyte to lock into a three-dimensional structure after crosslinking.Compared to linear polymers, the gel effect can be achieved with less polymer, and the formed gel structure is more stable, has excellent thermal stability, a large liquid content, and low impedance.

[0033] 3) The method of the present invention is simple and can be applied to the manufacturing process of existing general liquid batteries. The semi-solid battery obtained by this method has the same impedance as a liquid battery, and the drawback of the large impedance of existing semi-solid batteries is significantly improved.

[0034] Other features, objects and advantages of the present invention will become more apparent after a detailed description of non-limiting embodiments is given with reference to the following drawings, in which: [Brief explanation of the drawings]

[0035] [Figure 1] 1 shows the manufacturing flow of an in-situ polymerization type semi-solid battery. [Figure 2] 1 is a graph showing the 25° C., 50% SOC, 3C DCIR of the semi-solid battery according to Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0036] The manufacturing process of the in-situ polymerized semi-solid battery of the present invention is as follows.

[0037] The manufacturing process of the dry battery cells in the examples and comparative examples of the present invention is as follows.

[0038] First, the paste is mixed. The positive electrode paste is made of 9-based ternary material (NCM-Ni90, whose chemical formula is LiNi 0.9 Co 0.05 Mn 0.05 O2):conductive carbon black (Super P):carbon nanotubes (CNT800):adhesive (PVDF_1100)=97:1.1:0.8:1.1, all in mass percentage (wt.%).

[0039] The negative electrode paste had a blend ratio of graphite (BF): silicon-oxygen material (Si-O, purchased from Lanxi Zhide Battery, product number S0210): conductive carbon black (Super P): carbon nanotubes (CNT800): adhesive (sodium carboxymethyl cellulose CMC_500): adhesive (styrene butadiene rubber SBR) = 88.1:6.5:1.8:0.2:1.2:2.2, all percentages by mass (wt.%).

[0040] The paste is then applied. The positive electrode paste is applied to aluminum foil, and the negative electrode paste is applied to copper foil, then dried and wound. The resulting plates are then roll-pressed and cut. They are then wound around an electrode core. The resulting positive and negative electrode plates and separators are used, with the separator being a PE separator (3μm PVDF gel layer + 9μm substrate + 3μm Al2O3 ceramic layer + 3μm PVDF gel layer). The wound electrode core is then hot-pressed, and the top cover is welded before being assembled into a case to create a dry battery cell.

[0041] The dry battery cell is baked and then filled with electrolyte. As shown in FIG. 1, after the battery is assembled, a standard lithium battery liquid electrolyte is first filled with a predetermined amount of electrolyte. The electrolyte is a standard lithium battery liquid electrolyte and includes a lithium salt (which may be one or more selected from the group consisting of lithium hexafluorophosphate (LiPF), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiCF3SO3), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiODFB), and lithium difluorobis(oxalato)phosphate (LiDFBP)). After filling, an aging process is performed. The aging temperature is 20°C-50°C, preferably 45°C-48°C, and the aging time is 24 hours. After aging, a conventional formation process is carried out, with the formation temperature at 40±5°C and the pressure at 2000 N. After formation, a secondary injection (5-30 wt.% of the primary injection, preferably 10-20 wt.% of the total amount of the primary injection) is carried out to inject a mixture of polymer monomer, plasticizer, and initiator. The polymer monomer accounts for 70-95 wt.% of the secondary injection, preferably 80-90 wt.%, and the components are a combination of vinylene carbonate (VC) and tripropargyl phosphate (TPP), with a VC:TPP mass ratio of 10:1-100:1, preferably 20:1-50:1. The plasticizer accounts for 4.8-29.8 wt.% of the secondary liquid injection amount and is selected from one or more of tetraethyl silicate (TEOS), epoxy-grafted polyhedral epoxy oligomeric silsesquioxane (EP-POSS), boric acid (BA), and silicon tetrachloride (SiCl4), preferably epoxy-grafted polyhedral epoxy oligomeric silsesquioxane (EP-POSS).The initiator accounts for 0.01-0.4 wt.% of the secondary solution injection, preferably 0.05-0.1 wt.%, and is selected from one or more of 2,2-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ABVN), 2,2'-azobis(isobutyrate) dimethyl (AIBME), and dibenzoyl peroxide (BPO). After injection, aging is performed at an aging temperature of 20-50°C, preferably 25±5°C, for an aging time of 24±2 hours. After aging, the in-situ polymerization temperature is 58-65°C, and the in-situ polymerization time is 1.25-3 hours. Certain additives in the electrolyte are unstable at sustained high temperatures and easily undergo undesired decomposition side reactions with the plate material. Therefore, the temperature and time must be controlled to be neither too high nor too long. This is then followed by the usual capacity grading process to produce the finished battery cells.

[0042] The present invention will be described in detail below with reference to examples. The following examples are intended to help those skilled in the art to understand the present invention in depth, but are not intended to limit the present invention in any way. Those skilled in the art may make some adjustments and improvements without departing from the concept of the present invention, which are within the scope of protection of the present invention.

[0043] Example 1 After baking the dry battery cells, the primary solution was injected, and 450g of a standard lithium battery liquid electrolyte was injected. The general electrolyte used was ethylene carbonate (EC): ethyl methyl carbonate (EMC): diethyl carbonate (DEC): lithium hexafluorophosphate (LiPF6): lithium bis(fluorosulfonyl)imide (LiFSI): lithium difluorophosphate (LiPO2F2): fluoroethylene carbonate (FEC): ethylene sulfate (DTD) = 22:28.2:20:12:12:0.5:4.5:0.8, all in mass percentages (wt.%). After the primary solution injection, the cells were aged at 45°C for 24 hours. The cells were then formed under high-temperature and high-pressure conditions (temperature 40±5°C, pressure controlled to 2000N using a jig). After the formation, a secondary liquid injection was performed. The amount of the secondary liquid injection was 50 g, and the composition was vinylene carbonate (VC): tripropargyl phosphate (TPP): epoxy-grafted cage-type epoxy polyhedral oligomeric silsesquioxane (EP-POSS): 2,2-azobisisobutyronitrile (AIBN): dibenzoyl peroxide (BPO) = 87.1:2.9:9.9:0.08:0.02, all in mass percentages (wt.%). After aging at 25°C for 24 hours, the battery was placed in a high-temperature atmosphere at 60°C and a gel reaction was carried out for 2 hours. The gel polymerization of the electrolyte resulted in the formation of a semi-solid gel electrolyte. Finally, the battery was capacity-graded at room temperature to obtain the finished battery cell.

[0044] Figure 2 shows the 25°C 50% SOC 3C DCIR graph for the semi-solid battery obtained in this example. Specifically, the battery was adjusted to 50% SOC, placed in a 25°C oven, and discharged at a current of 3C for 30 seconds. The graph shows the discharge time on the horizontal axis and the voltage on the vertical axis. The impedance of the battery was calculated to be 53.3 mΩ, which is equivalent to the impedance of a liquid battery.

[0045] Examples 2 to 5 Examples 2 to 5 provide methods for manufacturing in-situ polymerization low-impedance semi-solid batteries, which are basically the same as Example 1. Specifically, the liquid injection amount and electrolyte composition are shown in Table 1.

[0046] Examples 6-7 Examples 6 and 7 provide methods for manufacturing in-situ polymerized low-impedance semi-solid batteries. Except for the type of plasticizer, the other specifications are the same as those of Example 1. Specifically, the injection amount and electrolyte composition are shown in Table 2.

[0047] Comparative Example 1 After baking the dry battery cell, 500g of electrolyte (the electrolyte in this comparative example is a mixture of a general electrolyte, a polymer monomer, a plasticizer, and an initiator) was injected. The electrolyte composition for the primary injection was EC:EMC:DEC:LiPF6:LiFSI:LiPO2F2:FEC:DTD:VC:TPP:EP-POSS:AIBN:BPO = 19.8:25.38:18:10.8:10.8:0.45:4.05:0.72:8.71:0.29:0.99:0.008:0.002 (all weight percentages). After injection, the battery was aged at 45°C for 24 hours. The battery was then placed in a high-temperature atmosphere at 60°C for 2 hours to allow the gel reaction to occur. The electrolyte polymerized and formed a semi-solid gel electrolyte. The battery is then formed under high temperature and high pressure conditions (temperature is controlled to 40±5°C and pressure is controlled to 2000N using a jig), aged for 24 hours at 25°C, and capacity grading is performed at room temperature to obtain the finished battery cell.

[0048] Comparative Example 2 After baking the dry battery cells, 450g of standard lithium battery liquid electrolyte was injected. The general electrolyte used was EC:EMC:DEC:LiPF6:LiFSI:LiPO2F2:FEC:DTD = 22:28.2:20:12:12:0.5:4.5:0.8, all in mass percentages (wt.%). After the initial injection, aging was performed at 45°C for 24 hours. The battery was then formed under high-temperature and high-pressure conditions (temperature controlled at 40±5°C and pressure controlled to 2000N using a jig). After formation, secondary liquid injection was performed. The amount of secondary liquid injected was 50g, and the composition was VC:trimethylene carbonate (TMC):EP-POSS:AIBN:BPO = 87.1:2.9:9.9:0.08:0.02, all mass percentages (wt.%). After aging at 25°C for 24 hours, the battery was placed in a high-temperature atmosphere at 60°C and a gel reaction was carried out for 2 hours, resulting in the formation of a semi-solid gel electrolyte through gel polymerization of the electrolyte. Finally, capacity grading was performed at room temperature to obtain the finished battery cell.

[0049] Comparative Example 3 After baking the dry battery cells, 450g of standard lithium battery liquid electrolyte was injected. The standard electrolyte was EC:EMC:DEC:LiPF6:LiFSI:LiPO2F2:FEC:DTD = 22:28.2:20:12:12:0.5:4.5:0.8, all by mass percentage (wt%). After the primary injection, the cells were aged at 45°C for 24 hours. The cells were then formed under high-temperature and high-pressure conditions (temperature 40±5°C, pressure controlled to 2000N with a jig). After formation, the secondary electrolyte was injected. 50g of secondary electrolyte was injected. The composition was VC:TPP:butanedinitrile (SN):AIBN:BPO = 87.1:2.9:9.9:0.08:0.02, all by mass percentage (wt%). After aging at 25°C for 24 hours, the battery was placed in a high-temperature atmosphere at 60°C for 2 hours to allow the gel reaction to proceed. The electrolyte polymerized into a semi-solid gel electrolyte, and the capacity was graded at room temperature to obtain the finished battery cell.

[0050] Comparative Example 4 After baking the dry battery cells, 450g of standard lithium battery liquid electrolyte was injected. The standard electrolyte was EC:EMC:DEC:LiPF6:LiFSI:LiPO2F2:FEC:DTD = 22:28.2:20:12:12:0.5:4.5:0.8, all by weight. After the primary injection, the cells were aged at 45°C for 24 hours. The cells were then formed under high-temperature and high-pressure conditions (temperature 40±5°C, pressure controlled to 2000N with a jig). After formation, the secondary electrolyte was injected. 50g of secondary electrolyte was injected, with a composition of VC:EP-POSS:AIBN:BPO = 90:9.9:0.08:0.02, all by weight. After aging at 25°C for 24 hours, the battery was placed in a high-temperature atmosphere at 60°C for 2 hours to allow the gel reaction to proceed. The electrolyte polymerized into a semi-solid gel electrolyte, and the capacity was graded at room temperature to obtain the finished battery cell.

[0051] Comparative Example 5 After baking the dry battery cells, 450 g of a standard lithium battery liquid electrolyte was injected. The standard electrolyte was EC:EMC:DEC:LiPF6:LiFSI:LiPO2F2:FEC:DTD = 22:28.2:20:12:12:0.5:4.5:0.8 (all mass percentages (wt.%)). After the primary electrolyte injection, the cells were aged at 45°C for 24 hours. The cells were then formed under high-temperature and high-pressure conditions (temperature 40±5°C, pressure controlled to 2000 N using a jig). After formation, the secondary electrolyte was injected. 50 g of the secondary electrolyte was injected. The composition was VC:Tert-butyl peroxide = 99.5:0.5 (mass percentage (wt.%)), all mass percentages (wt.%). After aging at 25°C for 24 hours, the battery was placed in a high-temperature atmosphere at 60°C for 2 hours to allow the gel reaction to proceed. The electrolyte polymerized into a semi-solid gel electrolyte, and the capacity was graded at room temperature to obtain the finished battery cell. The structural formula of tert-butyl peroxide is:

[0052] [ka]

[0053] is.

[0054] Performance test: The batteries obtained in each example and comparative example were adjusted to 50% SOC, then placed in a 25°C oven and discharged at a current of 3C for 30 seconds. A graph was created with the discharge time on the horizontal axis and the voltage on the vertical axis. The impedance of the batteries in each example and comparative example was calculated, and the specific impedance values ​​are shown in Tables 1 and 2.

[0055] [Table 1]

[0056] [Table 2]

[0057] Since the impedance of the batteries according to Examples 1 to 7 is close to that of a liquid battery, the manufacturing method of the present invention can effectively reduce the impedance of a semi-solid battery.

[0058] The difference between Examples 1, 4, 6, and 7 is the plasticizer. According to the experimental results, Example 1 uses EP-POSS as a plasticizer, which leads to a decrease in impedance.

[0059] The difference between Examples 1, 2, and 3 is the mass percentage of the polymer monomer in the amount of secondary liquid injected. According to the experimental results, in Example 1, the mass percentage of the polymer monomer in the amount of secondary liquid injected was controlled to 80 wt.%-90 wt.%, which led to a decrease in impedance.

[0060] The difference between Example 1 and Example 5 is the difference between the secondary liquid injection amount and the primary liquid injection amount. According to the experimental results, Example 1 leads to a decrease in impedance by controlling the secondary liquid injection amount to 10 wt.%-15 wt.% of the primary liquid injection amount.

[0061] The difference between Example 1 and Comparative Example 1 is that the liquid injection was not performed twice in Comparative Example 1. The results show that the impedance of the battery according to Example 1 is clearly lower than that of the battery according to Comparative Example 1, which indicates that the manufacturing method of the present invention can effectively reduce the impedance of semi-solid batteries.

[0062] The difference between Example 1 and Comparative Examples 2 and 4 is that Comparative Example 2 uses TMC instead of TPP as the auxiliary polymer monomer, while Comparative Example 4 does not use an auxiliary polymer monomer. The results show that the impedance of the battery according to Example 1 is lower than that of the batteries according to Comparative Examples 2 and 4, and therefore, the impedance of the semi-solid battery can be effectively reduced by using TPP as the auxiliary polymer monomer.

[0063] The difference between Examples 1, 4, 6, and 7 and Comparative Example 3 is that SN is used as a plasticizer in Comparative Example 3. The results show that the impedance of the batteries in Examples 1, 4, 6, and 7 is lower than that of the battery in Comparative Example 3, so using TEOS, EP-POSS, BA, or SiCl4 as a plasticizer can effectively reduce the impedance of semi-solid batteries.

[0064] The difference between Example 1 and Comparative Example 5 is that Comparative Example 5 does not use an auxiliary polymer monomer but uses tert-butyl peroxide as an initiator. The results show that the impedance of the battery according to Example 1 is lower than that of the battery according to Comparative Example 5, which indicates that the use of the auxiliary polymer monomer in combination with the initiators AIBN and BPO can effectively reduce the impedance of the semi-solid battery.

[0065] Although specific examples of the present invention have been described above, the present invention is not limited to the above-described embodiments, and those skilled in the art may make various modifications or alterations within the scope of the claims, provided that such modifications do not affect the essential content of the present invention.

Claims

1. An assembly step (S1) of assembling a positive electrode plate, a separator, and a negative electrode plate into a case to form a dry battery cell; A primary liquid injection step (S2) of injecting a liquid electrolyte for the lithium battery; an aging and formation step (S3); a secondary liquid injection step (S4) of injecting a mixture of a polymer monomer, a plasticizer, and an initiator, wherein the polymer monomer is a combination of vinylene carbonate and tripropargyl phosphate; and an aging step (S5) of gelling the mixture by in-situ polymerization to obtain a semi-solid battery; A method for producing an in-situ polymerized semi-solid battery, characterized in that the plasticizer contains one or more selected from the group consisting of tetraethyl silicate, epoxy-grafted cage-type epoxy polyhedral oligomeric silsesquioxane, boric acid, and silicon tetrachloride.

2. 2. The method for manufacturing an in-situ polymerized semi-solid battery according to claim 1, wherein the total amount of the secondary liquid injected is 5 wt. % to 30 wt. % of the total amount of the primary liquid injected.

3. 2. The method for manufacturing an in-situ polymerized semi-solid battery according to claim 1, wherein the polymer monomer accounts for 70 wt.%-95 wt.% of the total amount of the secondary liquid injection, the plasticizer accounts for 4.8 wt.%-29.8 wt.% of the total amount of the secondary liquid injection, and the initiator accounts for 0.01 wt.%-0.4 wt.% of the total amount of the secondary liquid injection, and the mass ratio of vinylene carbonate:tripropargyl phosphate in the polymer monomer is 10:1-100:

1.

4. 2. The method for producing an in situ polymerization semi-solid battery according to claim 1, wherein the initiator comprises one or more selected from the group consisting of 2,2-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyrate) dimethyl, and dibenzoyl peroxide.

5. The method for manufacturing an in-situ polymerization semi-solid battery according to claim 1, characterized in that in step S3, the aging temperature is 20°C-50°C, the aging time is 22h-26h, the formation temperature is 40±5°C, and the formation pressure is 2000N-4000N.

6. The method for manufacturing an in-situ polymerization semi-solid battery according to claim 1, wherein in step S5, the aging temperature is 20°C-50°C, the aging time is 22h-26h, and the in-situ polymerization time is 1.25h-3h.

7. 2. The method for producing an in situ polymerized semi-solid battery according to claim 1, wherein in step S2, the lithium salt in the liquid electrolyte of the lithium battery comprises one or more selected from the group consisting of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium bis(oxalate)borate, lithium difluoro(oxalato)borate, and lithium difluorobis(oxalato)phosphate.

8. 2. The method for manufacturing an in-situ polymerized semi-solid battery according to claim 1, wherein the negative electrode plate is a silicon-doped graphite negative electrode, a lithium metal negative electrode, or a metal alloy negative electrode, the silicon-doped graphite negative electrode having a silicon content of 3 wt.%-80 wt.%, and the metal alloy negative electrode comprises a Ga—Sn, Ge—Se, or Sn—Al alloy negative electrode.

9. The material of the positive electrode plate is NCM811, Ni90, NCM111, NCM532, NCM622, NCM712, nickel-cobalt-aluminum material, lithium manganese iron phosphate, or lithium iron (II) phosphate, and the structural formula of Ni90 is LiNi ｘ Co ｙ Mn ｚ O ２ 2. The method for manufacturing an in-situ polymerization semi-solid battery according to claim 1, wherein x≧0.

8.

10. The structural formula of Ni90 is LiNi ｘ Co ｙ Mn ｚ O ２ 10. The method for manufacturing an in-situ polymerization semi-solid battery according to claim 9, wherein y≧0, z≧0, and x+y+z=1.

11. 2. The method for manufacturing an in-situ polymerization type semi-solid battery according to claim 1, wherein in step S5, gelation is carried out by in-situ polymerization at 58°C-65°C.

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