Lithium battery pack with excellent cycle performance and preparation method thereof

Abstract

The present invention discloses a lithium battery pack with excellent cycle performance and a preparation method thereof, which belongs to the technical field of lithium battery pack preparation. The preparation method of the lithium battery pack with excellent cycle performance comprises the following steps: step 1: using polyvinylidene fluoride, N-methyl pyrrolidone, an organic active substance and a modified conductive agent as raw materials, preparing a positive electrode slurry, applying it to the AB surface of the aluminum current collector to obtain a positive electrode sheet; step 2: using graphite, carboxymethyl cellulose and deionized water as raw materials, obtaining a negative electrode slurry, applying it to the AB surface of the copper current collector to obtain a negative electrode sheet; step 3: winding the diaphragm, positive electrode sheet and negative electrode sheet into a core, vertically inserting it into a steel shell, drying it, injecting an electrolyte, welding it, obtaining a lithium battery, and then connecting the lithium batteries in series to obtain a lithium battery pack. The lithium battery pack prepared by this method has excellent energy density, cycle stability and rate performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery pack preparation, and particularly relates to a lithium battery pack with excellent cycle performance and a preparation method thereof. Background Art

[0002] Lithium-ion batteries, as a new energy storage device with high energy density, long life, and environmental friendliness, are a key development direction in future energy storage technology. Electrode materials are a key determinant of lithium battery performance. Cathode materials, such as lithium iron phosphate, lithium manganese oxide, and ternary lithium, each possess unique electrochemical properties. For example, lithium iron phosphate offers high stability, safety, and environmental friendliness, but its theoretical capacity is relatively low. Lithium manganese oxide offers lower costs, making it suitable for the production of large and medium-sized cells, but suffers from insufficient high-temperature stability and a low theoretical capacity. Ternary lithium batteries combine the advantages of lithium cobalt oxide and lithium manganese oxide, offering high energy density and excellent cycle performance. Graphite-based carbon materials have long been the mainstream anode materials, but the development of new materials such as graphene has opened up new avenues for improving anode performance. Through appropriate blending of cathode and cathode materials, carbon coating, and surface modification, the conductivity, stability, and lithium storage capacity of the electrodes can be significantly improved, thereby extending the battery's cycle life.

[0003] Patent CN118919680A discloses an ultra-high current lithium iron phosphate battery and its preparation method. First, a positive electrode slurry is prepared and coated on an aluminum foil surface to form a positive electrode sheet. The positive electrode sheet is then assembled with the negative electrode and separator, and the electrolyte is injected and sealed. Compared to the prior art, this invention improves the material's high current charge and discharge capabilities by coating the lithium iron phosphate with modified carbon nanotubes, thereby enhancing the battery's rate and cycle performance. However, the energy density, cycle stability, and rate performance of the lithium battery prepared using this method still need to be improved. Summary of the Invention

[0004] The object of the present invention is to provide a lithium battery pack with excellent cycle performance and a preparation method thereof, so as to solve the technical problems of poor energy density, cycle stability and rate performance of lithium battery packs in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing a lithium battery pack with excellent cycle performance, comprising the following steps:

[0007] Step 1: Add polyvinylidene fluoride to a container containing N-methylpyrrolidone and stir until completely dissolved. Mix and grind the organic active material and the modified conductive agent and add them to the container. Continue stirring and mixing to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on the AB surface of the aluminum current collector, dried, and compacted to obtain a positive electrode sheet.

[0008] Step 2: Graphite, carboxymethyl cellulose and deionized water are mixed and stirred to obtain a negative electrode slurry, and then the negative electrode slurry is evenly coated on the AB surface of the copper current collector, dried, and compacted to obtain a negative electrode sheet;

[0009] Step 3: Wind the diaphragm, positive electrode sheet, and negative electrode sheet into a core through a winding machine, and then insert the core vertically into the steel shell. After drying, inject electrolyte and weld to obtain a lithium battery. Then connect the lithium batteries in series to obtain a lithium battery pack.

[0010] Preferably, in the step 1, the amount ratio of polyvinylidene fluoride, N-methylpyrrolidone, organic active substance and modified conductive agent is (1-2) g: (8-12) mL: (5-8) g: (2-3) g, the mixing and grinding time is 10-15 min, and the stirring and mixing time is continued for 4-6 h. First, it is dried at 50-60 ° C for 10-12 h, and then vacuum dried at 80-85 ° C for 8-10 h; in the step 2, graphite, The dosage ratio of carboxymethyl cellulose and deionized water is (3-5) g: (1-2) g: (5-7) mL; in the step three, the diaphragm is composed of a polypropylene film, and the electrolyte is composed of lithium hexafluorophosphate, dimethyl carbonate, diethyl carbonate, cyclohexylbenzene and 1,2-dimethoxy-4,5-dinitrobenzene, and the dosage ratio is (10-12) g: (20-32) g: (12-18) g: (0.2-0.6) g: (0.1-0.4) g.

[0011] Preferably, the method for preparing the organic active substance comprises the following steps:

[0012] Q1: Tetrachloroperylene anhydride is added to an argon-filled container, followed by propionic acid, and then aminotriglycol monomethyl ether. The mixture is heated, stirred, and refluxed for reaction. After completion of the reaction, the mixture is poured into methanol, filtered, separated, purified, and recrystallized to obtain compound 1. Compound 1 is added to a container, followed by addition of cuprous iodide and L-proline. After vacuuming and introducing argon, dimethyl sulfoxide is added, the mixture is heated, stirred, and refluxed for reaction. After completion of the reaction, the mixture is poured into distilled water, stirred, filtered, washed, rotary evaporated, separated, purified, and precipitated to obtain compound 2.

[0013] Q2: Compound 2 is added to a container, and then bipyralidoboric acid pinacol ester, tris (pentafluorophenyl) phosphine and methoxy (cyclooctadiene) iridium polymer are added in sequence, argon is introduced and dichlorohexane is added, heated with stirring and reflux reaction is carried out, after the reaction is completed, rotary evaporation, separation and purification, sedimentation, to obtain compound 3; Compound 3 is added to a container, and then copper bromide is added, argon is introduced, and then a mixed solution of dioxane, methanol and distilled water after deoxygenation by aeration is added to the container, heated with stirring and reflux reaction is carried out, after the reaction is completed, it is added to distilled water, stirred, filtered, washed, rotary evaporated, recrystallized, dried and added to a container containing triisopropylsilyl acetylene, argon is introduced and dimethyl sulfoxide is added, heated with stirring and reaction is carried out, and then it is added to distilled water, filtered, washed, rotary evaporated, separated and purified, sedimentation, to obtain compound 4;

[0014] Q3: Compound 4 was added to a container containing a mixed solution of tetrahydrofuran and deionized water, stirred and mixed, and then tetrabutylammonium fluoride was added to a sample bottle containing a mixed solution of tetrahydrofuran and deionized water. After mixing evenly, the mixture in the sample bottle was added to the container with a syringe, and the mixture was sealed and reacted at room temperature. After the reaction was completed, the mixture was washed, rotary evaporated, separated and purified, and precipitated to obtain compound 5; cuprous chloride and tetramethylethylenediamine were added to a reaction tube containing dichloromethane, stirred and mixed, and compound 5 was added to dichloromethane. After mixing evenly, the mixture was added to the reaction tube. After heating for reaction, the mixture was washed, rotary evaporated, separated and purified, and precipitated to obtain an organic active substance.

[0015] In the above process, the synthesis reaction formula of the organic active substance is as follows:

[0016]

[0017] The results of mass spectrometry analysis of compound 1 were: m / z: 820.09 (100.0%), 818.10 (78.2%), 822.09 (48.2%), 821.10 (42.6%), 819.10 (32.8%), 823.09 (20.1%), 822.10 (10.6%),824.09 (10.4%), 820.10 (8.4%), 824.10 (5.3%), 825.09 (4.3%), 823.10 (2.4%),826.09 (1.1%), 825.10 (1.0%); the results of mass spectrometry analysis of compound 2 were: m / z: 750.17 (100.0%), 752.17 (63.9%), 751.18 (41.9%), 753.18 (28.8%), 752.18 (10.9%), 754.17(10.4%), 754.18 (6.8%), 755.17 (4.3%), 755.18 (1.4%), 756.18 (1.0%); the results of mass spectrometry analysis of compound 3 were: m / z: 1002.35 (100.0%), 1003.35 (69.1%), 1004.34 (48.8%),1001.35 (37.8%), 1005.35 (32.8%), 1004.35 (27.9%), 1006.35 (11.4%), 1006.34(8.0%), The m / z of compound 4 by mass spectrometry analysis were: 1003.36 (5.9%), 1000.35 (4.7%), 1007.34 (4.3%), 1005.34 (4.2%),1007.35 (2.8%), 1001.36 (2.6%), 1005.36 (2.5%), 1004.36 (2.0%), 1008.35(1.5%), 1006.36 (1.2%), 1002.36 (1.1%); the m / z of compound 4 by mass spectrometry analysis were: 1110.44(100.0%), 1112.44 (78.0%), 1111.44 (75.8%), 1113.44 (54.3%), 1112.45 (23.7%), 1114.44 (21.2%), 1114.45 (17.0%), 1115.44 (12.7%), 1113.45 (8.5%), 1115.45(4.4%), 1116.44 (4.3%), 1116.45 (1.3%), 1111.45 (1.3%), 1117.44 (1.0%); mass spectrometry analysis of compound 5 showed m / z: 798.17 (100.0%), 800.17 (63.9%), 799.18 (46.2%),801.18 (32.0%), 800.18 (12.8%), 802.17 (10.4%), 802.18 (8.0%), 803.17 (4.8%),803.18 (1.7%), 804.18 (1.2%); the results of mass spectrometry analysis of organic active substances were: m / z: 1594.32 (100.0%), 1595.32 (68.2%), 1592.32 (57.4%), 1593.32 (53.9%), 1597.32 (35.8%),1596.31 (35.2%), 1596.32 (35.0%), 1598.32 (16.5%), 1597.33 (10.0%), 1595.33(9.5%), 1598.31 (8.0%), 1599.31 (7.0%), 1599.32 (6.0%), 1600.32 (3.9%),1598.33 (3.4%), 1596.33 (2.8%), 1601.32 (1.2%), 1600.33 (1.1%), 1595.31(1.1%), 1600.31 (1.0%).

[0018] Preferably, in Q1, the amount ratio of tetrachloroperylene anhydride, propionic acid and aminotriglycol monomethyl ether is (8-13) g: (180-220) mL: (9-12) g, the heating stirring and reflux reaction temperature is 130-150°C, and the reaction time is 15-18 h; the amount ratio of compound 1, cuprous iodide, L-proline and dimethyl sulfoxide is (3-6) g: (18-20) g: (11-13) g: (100-130) mL, the heating stirring and reflux reaction temperature is 110-120°C, the stirring speed is 600-800 rpm, the reaction time is 16-20 h, and the stirring mixing time is 1-2 h.

[0019] Preferably, in Q2, the amount ratio of compound 2, bipyralidoboric acid pinacol ester, tris(pentafluorophenyl)phosphine, methoxy(cyclooctadiene) iridium polymer and dichlorohexacyclo is (1-1.5) g: (3-3.88) g: (0.081-0.086) g: (0.024-0.027) g: (18-25) mL, the heating stirring reflux reaction temperature is 100-120 ° C, the stirring speed is 600-700 rpm, and the reaction time is 10-12h; compound 3, copper bromide, dioxane, The dosage ratio of methanol, triisopropylsilyl acetylene and dimethyl sulfoxide is (1.2-1.8) g: (2.01-2.25) g: (38-42) mL: (14-18) mL: (1.41-1.84) g: (80-120) mL. The reaction temperature under heating and stirring reflux is 110-130°C, the stirring speed is 600-800 rpm, the reaction time is 10-12h, the stirring reaction time is 1-2h, the heating and stirring reaction temperature is 110-120°C, and the reaction time is 3-5h.

[0020] Preferably, in Q3, the dosage ratio of compound 4 and tetrabutylammonium fluoride is (0.3-0.5) g: (0.2-0.4) mL, and the closed reaction time is 10-12 h; the dosage ratio of cuprous chloride, tetramethylethylenediamine and compound 5 is (3-5) mg: (10-13) μL: (35-41.2) mg, the heating reaction temperature is 50-60°C, and the reaction time is 6-8 h.

[0021] Preferably, the preparation method of the modified conductive agent comprises the following steps:

[0022] S1: Cyclohexane, 2-tert-butylphenol, and benzaldehyde are added to a container, diethylamine is added under stirring, the temperature is increased to react, and then heated under reduced pressure for distillation. Subsequently, a mixed solution of anhydrous ethanol and cyclohexane is added to the container, recrystallized, filtered, washed, and dried to obtain intermediate A;

[0023] S2: Add intermediate A, toluene, and tetracycloheptane to a container, heat with stirring at reflux, and purify by rotary evaporation to obtain a crude product. Add the crude product and sodium sulfate to methanol, heat with stirring under a nitrogen atmosphere, and then concentrate in vacuo. Add ethyl acetate, extract, dry, and filter to obtain intermediate B.

[0024] S3: Add intermediate B, graphene and tetrahydrofuran to a container, then add Grubbs catalyst, react at room temperature, and after the reaction is completed, dilute and add to methanol, stir to react, filter, vacuum dry, wash, and dry to obtain a modified conductive agent.

[0025] In the above process, the synthetic reaction formula of the modified conductive agent is as follows:

[0026]

[0027] Preferably, in S1, the dosage ratio of cyclohexane, 2-tert-butylphenol, benzaldehyde, diethylamine and the mixed solution is (80-120) mL: (90-110) g: (62-68) g: (5-6) g: (130-135) mL, the temperature of the reaction is 100-120° C., the reaction time is 20-24 h, the temperature of the heating and reduced pressure distillation is 120-125° C., the reduced pressure distillation time is 1-2 h, and the volume ratio of anhydrous ethanol to cyclohexane is 3:1.

[0028] Preferably, in S2, the amount ratio of intermediate A, toluene, and tetracycloheptane is (14-16) g: (40-60) mL: (9-10.2) g, the heating and stirring reflux temperature is 50-65°C, and the reflux time is 72-90 h. The amount ratio of crude product, sodium sulfate, methanol, and ethyl acetate is (6-10) g: (8-8.5) g: (80-120) mL: (90-110) mL, the heating and stirring temperature is 45-55°C, and the stirring time is 4-6 h. In S3, the amount ratio of intermediate B, graphene, tetrahydrofuran, and Grubbs' catalyst is (50-70) mg: (30-40) mg: (2-4) mL: (1.2-1.5) mg, the reaction time at room temperature is 2-4 h, and the stirring reaction time is 1-2 h.

[0029] Preferably, the lithium battery pack with excellent cycle performance is prepared by the method according to any one of claims 1 to 9.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. The present invention first uses tetrachloroperylene anhydride, aminotriglycol monomethyl ether, biboronic acid pinacol ester, triisopropylsilyl acetylene, tetrabutylammonium fluoride and tetramethylethylenediamine as raw materials to prepare an organic active substance, and then uses 2-tert-butylphenol, benzaldehyde, tetracycloheptane and graphene as raw materials to prepare a modified conductive agent. Applying both to a lithium battery pack can effectively improve its energy density, cycle stability and rate performance.

[0032] 2. The present invention adds the prepared organic active material to the preparation process of the lithium battery pack, which can effectively improve its energy density and cycle stability. The conjugated system of the prepared organic active material is significantly expanded, making the electron cloud distribution wider and the electron transmission efficiency improved. As a result, more electrons participate in the reaction during the charge and discharge process of the lithium battery, thereby increasing the energy density. At the same time, the expansion of the conjugated system enhances the π-π stacking effect between molecules, further improving the charge and discharge efficiency. The stable molecular structure of the organic active material makes the battery less likely to decompose or reconstruct during the charge and discharge process, ensuring the long life and cycle stability of the battery and extending the service life of the lithium battery pack.

[0033] 3. The present invention applies the prepared modified conductive agent to a lithium battery pack, which can effectively improve the cycle stability and rate performance of the battery. The modified conductive agent has a high molecular weight and a complex chemical structure, which enables it to remain relatively stable during the battery charge and discharge process and is not prone to decomposition or degradation. The stable structure helps to reduce the shedding and differentiation of the electrode material, thereby extending the service life of the battery. The stable chemical properties of the modified conductive agent are conducive to its chemical stability in the internal environment of the battery, thereby reducing harmful chemical reactions inside the battery and improving the cycle stability of the battery. At the same time, the conjugated structure and electron transmission channel of the modified conductive agent give it excellent conductive properties, which can enable the battery to transfer charges and ions faster and improve the rate performance of the battery. The quinone group it contains has high redox activity, which can enable the battery pack to quickly carry out charge transfer reactions, reduce the polarization phenomenon inside the battery, and enable the battery to maintain high performance under high rate charge and discharge conditions. At the same time, the presence of the modified conductive agent can also improve the ion transmission rate inside the battery and improve the rate performance of the battery pack. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] Example 1: This example discloses a method for preparing an organic active substance, comprising the following steps:

[0036] Q1: 10.5 g of tetrachloroperylene anhydride was added to a container filled with argon, followed by the addition of 200 mL of propionic acid, followed by the addition of 10.5 g of aminotriglycol monomethyl ether, and the mixture was heated at 140° C. with stirring and reflux for 16 h. After the reaction was completed, the mixture was poured into methanol, filtered, separated and purified, and recrystallized to obtain compound 1; 4.5 g of compound 1 was added to a container, followed by the addition of 19 g of cuprous iodide and 12 g of L-proline. After vacuuming and introducing argon, 120 mL of dimethyl sulfoxide was added, and the mixture was heated at 600 rpm and refluxed at 120° C. for 20 h. After the reaction was completed, the mixture was poured into distilled water, stirred and mixed for 1 h, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 2;

[0037] Q2: 1.25g of compound 2 was added to a container, and then 3.44g of bipyraclostrobin, 0.083g of tris(pentafluorophenyl)phosphine and 0.026g of methoxy(cyclooctadiene)iridium polymer were added in sequence, and 22mL of dichlorohexacyclopenta ... A mixed solution of mL dioxane, 16 mL methanol and 8 mL distilled water was added to a container, heated and stirred at 800 rpm and 130°C for 12 h, and then added to 500 mL distilled water, stirred for 1 h, filtered, washed, rotary evaporated, recrystallized, dried, and added to a container containing 1.63 g triisopropylsilyl acetylene. After argon was introduced, 100 mL dimethyl sulfoxide was added, and the mixture was heated and stirred at 120°C for 4 h. The mixture was then added to distilled water, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 4;

[0038] Q3: 0.4 g of compound 4 was added to a container containing a mixed solution of 120 mL of tetrahydrofuran and 6 mL of deionized water, stirred and mixed, and then 0.3 mL of tetrabutylammonium fluoride was added to a sample bottle containing a mixed solution of 10 mL of tetrahydrofuran and 0.3 mL of deionized water. After mixing evenly, the mixture in the sample bottle was added to the container with a syringe, and the reaction was sealed at room temperature for 12 hours. After the reaction was completed, the mixture was washed, rotary evaporated, separated and purified, and precipitated to obtain compound 5; 4 mg of cuprous chloride and 11.5 μL of tetramethylethylenediamine were added to a reaction tube containing 10 mL of dichloromethane, stirred and mixed, and 38.1 mg of compound 5 was added to 10 mL of dichloromethane. After mixing evenly, it was added to the reaction tube, heated at 50°C for 6 hours, washed, rotary evaporated, separated and purified, and precipitated to obtain an organic active substance.

[0039] This embodiment discloses a method for preparing a modified conductive agent, comprising the following steps:

[0040] S1: 100 mL of cyclohexane, 100 g of 2-tert-butylphenol, and 66 g of benzaldehyde were added to a container, 5.5 g of diethylamine was added under stirring, and the reaction was heated to 110°C for 24 h, followed by heating at 125°C for 1 h under reduced pressure distillation. Subsequently, 132 mL of a mixed solution (composed of anhydrous ethanol and cyclohexane in a volume ratio of 3:1) was added to the container, and the mixture was recrystallized, filtered, washed, and dried to obtain intermediate A.

[0041] S2: 15 g of intermediate A, 50 mL of toluene, and 9.6 g of tetracycloheptane were added to a container, heated at 65°C with stirring and reflux for 72 h, and rotary evaporated for purification to obtain a crude product. 8 g of the crude product and 8.25 g of sodium sulfate were added to 100 mL of methanol, heated at 50°C with stirring under a nitrogen atmosphere for 6 h, and then concentrated in vacuo. 100 mL of ethyl acetate was added, extracted, dried, and filtered to obtain intermediate B.

[0042] S3: 60 mg of intermediate B, 35 mg of graphene and 3 mL of tetrahydrofuran were added to a container, and then 1.35 mg of Grubbs' catalyst was added. The reaction was carried out at room temperature for 4 hours. After the reaction was completed, the mixture was diluted and added to methanol. The mixture was stirred for 1 hour, filtered, vacuum dried, washed, and dried to obtain a modified conductive agent.

[0043] This embodiment discloses a method for preparing a lithium battery pack with excellent cycle performance, comprising the following steps:

[0044] Step 1: Add 1.5g of polyvinylidene fluoride to a container containing 10mL of N-methylpyrrolidone and stir until completely dissolved. Mix 6.5g of organic active material and 2.5g of modified conductive agent and grind them for 15min before adding them to the container. Continue stirring and mixing for 6h to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on the AB surface of the aluminum current collector. First, dry it at 55°C for 12h, then vacuum dry it at 85°C for 9h, and compact it to obtain a positive electrode sheet.

[0045] Step 2: 4 g of graphite, 1.5 g of carboxymethyl cellulose, and 6 mL of deionized water were mixed and stirred to obtain a negative electrode slurry, and then the negative electrode slurry was evenly coated on the AB surface of the copper current collector, dried, and compacted to obtain a negative electrode sheet;

[0046] Step 3: Wind the polypropylene film, positive electrode sheet, and negative electrode sheet into a core through a winding machine, and then insert the core vertically into the steel shell. After drying, inject the electrolyte (consisting of 11g lithium hexafluorophosphate, 26g dimethyl carbonate, 15g diethyl carbonate, 0.4g cyclohexylbenzene and 0.25g 1,2-dimethoxy-4,5-dinitrobenzene), weld it, and obtain a lithium battery. Then, connect the lithium batteries in series to obtain a lithium battery pack.

[0047] Example 2: This example discloses a method for preparing an organic active substance, comprising the following steps:

[0048] Q1: 8 g of tetrachloroperylene anhydride was added to a container filled with argon, followed by 180 mL of propionic acid, followed by 9 g of aminotriglycol monomethyl ether, and the mixture was heated at 140° C. with stirring and reflux for 16 h. After the reaction was completed, the mixture was poured into methanol, filtered, separated and purified, and recrystallized to obtain compound 1; 3 g of compound 1 was added to a container, followed by 18 g of cuprous iodide and 11 g of L-proline. After vacuuming and introducing argon, 110 mL of dimethyl sulfoxide was added, and the mixture was heated at 600 rpm and 120° C. with stirring and reflux for 20 h. After the reaction was completed, the mixture was poured into distilled water, stirred and mixed for 1 h, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 2;

[0049] Q2: 1.5g of compound 2 was added to a container, and then 3g of bipyraclostrobin, 0.081g of tris(pentafluorophenyl)phosphine and 0.024g of methoxy(cyclooctadiene)iridium polymer were added in sequence, argon was introduced, 18mL of dichlorohexacyclopentane was added, 700rpm, 110℃ was heated and stirred under reflux for 12h, after the reaction was completed, rotary evaporation was performed, separation and purification were carried out, and precipitation was performed to obtain compound 3; 1.2g of compound 3 was added to the container, and then 2.01g of copper bromide was added, argon was introduced, and then 38mL of deoxygenated cyclopenta ... A mixed solution of 1 mL of dioxane, 14 mL of methanol, and 8 mL of distilled water was added to a container, heated and stirred at 800 rpm and 130°C for 12 h, and then added to 500 mL of distilled water, stirred for 1 h, filtered, washed, rotary evaporated, recrystallized, dried, and added to a container containing 1.41 g of triisopropylsilyl acetylene. After passing argon, 80 mL of dimethyl sulfoxide was added, heated and stirred at 120°C for 4 h, and then added to distilled water, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 4;

[0050] Q3: 0.3 g of compound 4 was added to a container containing a mixed solution of 120 mL of tetrahydrofuran and 6 mL of deionized water, stirred and mixed, and then 0.2 mL of tetrabutylammonium fluoride was added to a sample bottle containing a mixed solution of 10 mL of tetrahydrofuran and 0.3 mL of deionized water. After mixing evenly, the mixture in the sample bottle was added to the container with a syringe, and the reaction was sealed at room temperature for 12 hours. After the reaction was completed, the mixture was washed, rotary evaporated, separated and purified, and precipitated to obtain compound 5; 3 mg of cuprous chloride and 10 μL of tetramethylethylenediamine were added to a reaction tube containing 10 mL of dichloromethane, stirred and mixed, and 35 mg of compound 5 was added to 10 mL of dichloromethane. After mixing evenly, it was added to the reaction tube, heated at 50°C for 6 hours, washed, rotary evaporated, separated and purified, and precipitated to obtain an organic active substance.

[0051] This embodiment discloses a method for preparing a modified conductive agent, comprising the following steps:

[0052] S1: 80 mL of cyclohexane, 90 g of 2-tert-butylphenol, and 62 g of benzaldehyde were added to a container, 5 g of diethylamine was added under stirring, and the reaction was carried out at 110°C for 24 h, followed by heating at 125°C and distillation under reduced pressure for 1 h. Subsequently, 130 mL of a mixed solution (composed of anhydrous ethanol and cyclohexane in a volume ratio of 3:1) was added to the container, and the mixture was recrystallized, filtered, washed, and dried to obtain intermediate A.

[0053] S2: 14 g of intermediate A, 40 mL of toluene, and 10.2 g of tetracycloheptane were added to a container, heated at 65°C with stirring and reflux for 72 h, and rotary evaporated for purification to obtain a crude product. 6 g of the crude product and 8 g of sodium sulfate were added to 80 mL of methanol, heated at 50°C with stirring under a nitrogen atmosphere for 6 h, and then concentrated in vacuo. 90 mL of ethyl acetate was added, extracted, dried, and filtered to obtain intermediate B.

[0054] S3: 50 mg of intermediate B, 30 mg of graphene and 2 mL of tetrahydrofuran were added to a container, and then 1.2 mg of Grubbs' catalyst was added. The reaction was carried out at room temperature for 4 h. After the reaction was completed, the mixture was diluted and added to methanol. The mixture was stirred for 1 h. The mixture was filtered, vacuum dried, washed, and dried to obtain a modified conductive agent.

[0055] This embodiment discloses a method for preparing a lithium battery pack with excellent cycle performance, comprising the following steps:

[0056] Step 1: Add 1g of polyvinylidene fluoride to a container containing 8mL of N-methylpyrrolidone and stir until completely dissolved. Mix 5g of organic active material and 2g of modified conductive agent and grind them for 15min before adding them to the container. Continue stirring and mixing for 6h to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on the AB surface of the aluminum current collector. First, dry it at 55°C for 12h, then vacuum dry it at 85°C for 9h, and compact it to obtain a positive electrode sheet.

[0057] Step 2: 3 g of graphite, 1 g of carboxymethyl cellulose and 5 mL of deionized water were mixed and stirred to obtain a negative electrode slurry, and then the negative electrode slurry was evenly coated on the AB surface of the copper current collector, dried, and compacted to obtain a negative electrode sheet;

[0058] Step 3: Wind the polypropylene film, positive electrode sheet, and negative electrode sheet into a core through a winding machine, and then insert the core vertically into the steel shell. After drying, inject the electrolyte (consisting of 10g lithium hexafluorophosphate, 20g dimethyl carbonate, 12g diethyl carbonate, 0.2g cyclohexylbenzene and 0.1g 1,2-dimethoxy-4,5-dinitrobenzene), weld it, and obtain a lithium battery. Then, connect the lithium batteries in series to obtain a lithium battery pack.

[0059] Example 3: This example discloses a method for preparing an organic active substance, comprising the following steps:

[0060] Q1: 13 g of tetrachloroperylene anhydride was added to a container filled with argon, followed by the addition of 220 mL of propionic acid, followed by the addition of 12 g of aminotriglycol monomethyl ether, and the mixture was heated at 140° C. with stirring and reflux for 16 h. After the reaction was completed, the mixture was poured into methanol, filtered, separated and purified, and recrystallized to obtain compound 1; 6 g of compound 1 was added to a container, followed by the addition of 20 g of cuprous iodide and 13 g of L-proline. After vacuuming and introducing argon, 130 mL of dimethyl sulfoxide was added, and the mixture was heated at 600 rpm and 120° C. with stirring and reflux for 20 h. After the reaction was completed, the mixture was poured into distilled water, stirred and mixed for 1 h, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 2;

[0061] Q2: 2g of compound 2 was added to a container, and then 3.88g of biboronic acid pinacol ester, 0.086g of tris(pentafluorophenyl)phosphine and 0.027g of methoxy(cyclooctadiene) iridium polymer were added in sequence, argon was introduced, 25mL of dichlorohexacyclopenta ... A mixed solution of 1 mL of dioxane, 18 mL of methanol, and 8 mL of distilled water was added to a container, heated and stirred at 800 rpm and 130°C for 12 h, and then added to 500 mL of distilled water, stirred for 1 h, filtered, washed, rotary evaporated, recrystallized, dried, and added to a container containing 1.84 g of triisopropylsilyl acetylene. After passing argon, 120 mL of dimethyl sulfoxide was added, and the mixture was heated and stirred at 120°C for 4 h. The mixture was then added to distilled water, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 4;

[0062] Q3: Add 0.5 g of compound 4 to a container containing a mixed solution of 120 mL of tetrahydrofuran and 6 mL of deionized water, stir to mix, then add 0.4 mL of tetrabutylammonium fluoride to a sample bottle containing a mixed solution of 10 mL of tetrahydrofuran and 0.3 mL of deionized water, mix evenly, add the mixture in the sample bottle to the container with a syringe, and react in a sealed manner at room temperature for 12 hours. After the reaction is completed, wash, rotary evaporate, separate and purify, and precipitate to obtain compound 5; add 5 mg of cuprous chloride and 13 μL of tetramethylethylenediamine to a reaction tube containing 10 mL of dichloromethane, stir to mix, add 41.2 mg of compound 5 to 10 mL of dichloromethane, mix evenly, add to the reaction tube, heat at 50°C for 6 hours, wash, rotary evaporate, separate and purify, and precipitate to obtain an organic active substance.

[0063] This embodiment discloses a method for preparing a modified conductive agent, comprising the following steps:

[0064] S1: 120 mL of cyclohexane, 110 g of 2-tert-butylphenol, and 68 g of benzaldehyde were added to a container, 6 g of diethylamine was added under stirring, and the reaction was heated to 110°C for 24 h, followed by heating at 125°C and distillation under reduced pressure for 1 h. Subsequently, 135 mL of a mixed solution (composed of anhydrous ethanol and cyclohexane in a volume ratio of 3:1) was added to the container, and the mixture was recrystallized, filtered, washed, and dried to obtain intermediate A.

[0065] S2: 16 g of intermediate A, 60 mL of toluene, and 9 g of tetracycloheptane were added to a container, heated at 65°C with stirring and reflux for 72 h, and rotary evaporated for purification to obtain a crude product. 10 g of the crude product and 8.5 g of sodium sulfate were added to 120 mL of methanol, heated at 50°C with stirring under a nitrogen atmosphere for 6 h, and then concentrated in vacuo. 110 mL of ethyl acetate was added, extracted, dried, and filtered to obtain intermediate B.

[0066] S3: 70 mg of intermediate B, 40 mg of graphene and 4 mL of tetrahydrofuran were added to a container, and then 1.5 mg of Grubbs' catalyst was added. The reaction was carried out at room temperature for 4 hours. After the reaction was completed, the mixture was diluted and added to methanol. The mixture was stirred for 1 hour, filtered, vacuum dried, washed, and dried to obtain a modified conductive agent.

[0067] This embodiment discloses a method for preparing a lithium battery pack with excellent cycle performance, comprising the following steps:

[0068] Step 1: Add 2g of polyvinylidene fluoride to a container containing 12mL of N-methylpyrrolidone and stir until completely dissolved. Mix 8g of organic active material and 3g of modified conductive agent and grind them for 15min before adding them to the container. Continue stirring and mixing for 6h to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on the AB surface of the aluminum current collector. First, dry it at 55°C for 12h, then vacuum dry it at 85°C for 9h, and compact it to obtain a positive electrode sheet.

[0069] Step 2: 5 g of graphite, 2 g of carboxymethyl cellulose and 7 mL of deionized water were mixed and stirred to obtain a negative electrode slurry, and then the negative electrode slurry was evenly coated on the AB surface of the copper current collector, dried, and compacted to obtain a negative electrode sheet;

[0070] Step 3: Wind the polypropylene film, positive electrode sheet, and negative electrode sheet into a core through a winding machine, and then insert the core vertically into the steel shell. After drying, inject the electrolyte (consisting of 12g lithium hexafluorophosphate, 32g dimethyl carbonate, 18g diethyl carbonate, 0.6g cyclohexylbenzene and 0.4g 1,2-dimethoxy-4,5-dinitrobenzene), weld it, and obtain a lithium battery. Then, connect the lithium batteries in series to obtain a lithium battery pack.

[0071] Example 4: This example discloses a method for preparing an organic active substance, comprising the following steps:

[0072] Q1: 9 g of tetrachloroperylene anhydride was added to a container filled with argon, followed by the addition of 190 mL of propionic acid, followed by the addition of 10 g of aminotriglycol monomethyl ether, and the mixture was heated at 140° C. with stirring and reflux for 16 h. After the reaction was completed, the mixture was poured into methanol, filtered, separated and purified, and recrystallized to obtain compound 1; 4 g of compound 1 was added to a container, followed by the addition of 18.5 g of cuprous iodide and 11.5 g of L-proline. After vacuuming and introducing argon, 115 mL of dimethyl sulfoxide was added, and the mixture was heated at 600 rpm and 120° C. with stirring and reflux for 20 h. After the reaction was completed, the mixture was poured into distilled water, stirred and mixed for 1 h, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 2;

[0073] Q2: 1.1g of compound 2 was added to a container, and then 3.22g of bipyraclostrobin, 0.082g of tris(pentafluorophenyl)phosphine and 0.025g of methoxy(cyclooctadiene)iridium polymer were added in sequence, and 19mL of dichlorohexacyclopenta ... A mixed solution of mL dioxane, 15 mL methanol and 8 mL distilled water was added to a container, heated and stirred at 800 rpm and 130°C for 12 h, and then added to 500 mL distilled water, stirred for 1 h, filtered, washed, rotary evaporated, recrystallized, dried, and added to a container containing 1.52 g triisopropylsilyl acetylene. After passing argon, 90 mL dimethyl sulfoxide was added, heated and stirred at 120°C for 4 h, and then added to distilled water, filtered, washed, rotary evaporated, separated and purified, and precipitated to obtain compound 4;

[0074] Q3: 0.35 g of compound 4 was added to a container containing a mixed solution of 120 mL of tetrahydrofuran and 6 mL of deionized water, stirred and mixed, and then 0.25 mL of tetrabutylammonium fluoride was added to a sample bottle containing a mixed solution of 10 mL of tetrahydrofuran and 0.3 mL of deionized water. After mixing evenly, the mixture in the sample bottle was added to the container with a syringe, and the reaction was sealed at room temperature for 12 hours. After the reaction was completed, the mixture was washed, rotary evaporated, separated and purified, and precipitated to obtain compound 5; 3.5 mg of cuprous chloride and 11 μL of tetramethylethylenediamine were added to a reaction tube containing 10 mL of dichloromethane, stirred and mixed, and 36 mg of compound 5 was added to 10 mL of dichloromethane. After mixing evenly, it was added to the reaction tube, heated at 50°C for 6 hours, washed, rotary evaporated, separated and purified, and precipitated to obtain an organic active substance.

[0075] This embodiment discloses a method for preparing a modified conductive agent, comprising the following steps:

[0076] S1: 90 mL of cyclohexane, 95 g of 2-tert-butylphenol, and 64 g of benzaldehyde were added to a container, 5.2 g of diethylamine was added under stirring, and the reaction was heated to 110°C for 24 h, followed by heating at 125°C and distillation under reduced pressure for 1 h. Subsequently, 131 mL of a mixed solution (composed of anhydrous ethanol and cyclohexane in a volume ratio of 3:1) was added to the container, and the mixture was recrystallized, filtered, washed, and dried to obtain intermediate A;

[0077] S2: 14.5 g of intermediate A, 45 mL of toluene, and 9.2 g of tetracycloheptane were added to a container, heated at 65° C. with stirring and reflux for 72 h, and rotary evaporated for purification to obtain a crude product. 9 g of the crude product and 8.1 g of sodium sulfate were added to 90 mL of methanol, heated at 50° C. with stirring under a nitrogen atmosphere for 6 h, and then concentrated in vacuo. 95 mL of ethyl acetate was added, extracted, dried, and filtered to obtain intermediate B.

[0078] S3: 55 mg of intermediate B, 32 mg of graphene and 2.5 mL of tetrahydrofuran were added to a container, and then 1.3 mg of Grubbs' catalyst was added. The reaction was carried out at room temperature for 4 h. After the reaction was completed, the mixture was diluted and added to methanol. The mixture was stirred for 1 h, filtered, vacuum dried, washed, and dried to obtain a modified conductive agent.

[0079] This embodiment discloses a method for preparing a lithium battery pack with excellent cycle performance, comprising the following steps:

[0080] Step 1: Add 1.2g of polyvinylidene fluoride to a container containing 9mL of N-methylpyrrolidone and stir until completely dissolved. Mix 6g of organic active material and 2.2g of modified conductive agent and grind them for 15min before adding them to the container. Continue stirring and mixing for 6h to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on the AB surface of the aluminum current collector. First, dry it at 55°C for 12h, then vacuum dry it at 85°C for 9h, and compact it to obtain a positive electrode sheet.

[0081] Step 2: 3.5 g of graphite, 1.2 g of carboxymethyl cellulose, and 5.5 mL of deionized water were mixed and stirred to obtain a negative electrode slurry, and then the negative electrode slurry was evenly coated on the AB surface of the copper current collector, dried, and compacted to obtain a negative electrode sheet;

[0082] Step 3: The polypropylene film, positive electrode sheet, and negative electrode sheet are wound into a core by a winding machine, and then the core is vertically inserted into the steel shell. After drying, the electrolyte (consisting of 10.5g lithium hexafluorophosphate, 22g dimethyl carbonate, 14g diethyl carbonate, 0.3g cyclohexylbenzene and 0.2g 1,2-dimethoxy-4,5-dinitrobenzene) is injected and welded to obtain a lithium battery. The lithium batteries are then connected in series to obtain a lithium battery pack.

[0083] Comparative Example 1: Compared with Example 1, in Comparative Example 1, during the preparation of the organic active substance, tetrachloroperylene anhydride was not added, and other conditions remained unchanged.

[0084] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the preparation of the modified conductive agent, no 2-tert-butylphenol was added, and other conditions remained unchanged.

[0085] Experimental Example: The lithium battery packs prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests. The energy density and cycle performance of the samples were tested in accordance with IEC62660-1-2018. Under room temperature, the sample was charged to 4.35V at a constant current of 1C, and then charged to a current of ≤0.05C at a constant voltage of 4.35V. After standing for 5 minutes, it was discharged at a constant current of 0.2C to a cut-off voltage of 3V. At this time, the actual discharge capacity was recorded as D0. Then, it was charged to 4.35V at a constant current of 1C, and then charged to a current of ≤0.05C at a constant voltage of 4.35V. Finally, it was discharged at a cut-off voltage of 3V at 2C. The actual discharge capacity at this time was recorded as D1. Rate performance = [(D1-D0) / D0] × 100%. The test results are shown in Table 1:

[0086] Table 1

[0087] project <![CDATA[Energy density / Wh·kg -1 > Capacity retention after 300 cycles / % Rate performance / % Example 1 185.3 98.4 95.4 Example 2 182.7 98.1 95.2 Example 3 183.5 97.5 95.3 Example 4 184.8 97.8 94.8 Comparative Example 1 166.2 90.3 94.1 Comparative Example 2 183.3 90.5 85.2

[0088] The test results in Table 1 show that the lithium battery packs prepared in Examples 1-4 of the present invention have excellent energy density, cycle stability, and rate performance. A comparison between Comparative Example 1 and Examples 1-4 shows that the addition of tetrachloroperylene anhydride can effectively improve the energy density and cycle stability of the lithium battery pack; a comparison between Comparative Example 2 and Examples 1-4 shows that the addition of 2-tert-butylphenol can effectively improve the cycle stability and rate performance of the lithium battery pack.

[0089] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0090] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a lithium battery pack with excellent cycle performance, characterized in that: The following steps are involved: Step 1: Add polyvinylidene fluoride to a container containing N-methylpyrrolidone and stir until completely dissolved. Mix and grind the organic active material and the modified conductive agent and add them to the container. Continue stirring and mixing to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on the AB surface of the aluminum current collector, dried, and compacted to obtain a positive electrode sheet. Step 2: Graphite, carboxymethyl cellulose and deionized water are mixed and stirred to obtain a negative electrode slurry, and then the negative electrode slurry is evenly coated on the AB surface of the copper current collector, dried, and compacted to obtain a negative electrode sheet; Step 3: The separator, positive electrode sheet, and negative electrode sheet are wound into a core by a winding machine, and then the core is vertically inserted into a steel shell. After drying, the electrolyte is injected. The electrolyte is composed of lithium hexafluorophosphate, dimethyl carbonate, diethyl carbonate, cyclohexylbenzene and 1,2-dimethoxy-4,5-dinitrobenzene. The usage ratio is (10-12) g: (20-32) g: (12-18) g: (0.2-0.6) g: (0.1-0.4) g. The lithium battery is obtained by welding, and then the lithium battery is connected in series to obtain a lithium battery pack. The preparation method of the organic active substance comprises the following steps: Q1: Tetrachloroperylene anhydride is added to an argon-filled container, followed by propionic acid, and then aminotriglycol monomethyl ether. The mixture is heated, stirred, and refluxed for reaction. After completion of the reaction, the mixture is poured into methanol, filtered, separated, purified, and recrystallized to obtain compound 1. Compound 1 is added to a container, followed by addition of cuprous iodide and L-proline. After vacuuming and introducing argon, dimethyl sulfoxide is added, the mixture is heated, stirred, and refluxed for reaction. After completion of the reaction, the mixture is poured into distilled water, stirred, filtered, washed, rotary evaporated, separated, purified, and precipitated to obtain compound 2. Q2: Compound 2 is added to a container, and then bipyralidoboric acid pinacol ester, tris (pentafluorophenyl) phosphine and methoxy (cyclooctadiene) iridium polymer are added in sequence, argon is introduced and dichlorohexane is added, heated with stirring and reflux reaction is carried out, after the reaction is completed, rotary evaporation, separation and purification, sedimentation, to obtain compound 3; Compound 3 is added to a container, and then copper bromide is added, argon is introduced, and then a mixed solution of dioxane, methanol and distilled water after deoxygenation by aeration is added to the container, heated with stirring and reflux reaction is carried out, after the reaction is completed, it is added to distilled water, stirred, filtered, washed, rotary evaporated, recrystallized, dried and added to a container containing triisopropylsilyl acetylene, argon is introduced and dimethyl sulfoxide is added, heated with stirring and reaction is carried out, and then it is added to distilled water, filtered, washed, rotary evaporated, separated and purified, sedimentation, to obtain compound 4; Q3: Compound 4 was added to a container containing a mixed solution of tetrahydrofuran and deionized water, stirred and mixed, and then tetrabutylammonium fluoride was added to a sample bottle containing a mixed solution of tetrahydrofuran and deionized water. After mixing, the mixture in the sample bottle was added to the container with a syringe, and the mixture was sealed and reacted at room temperature. After the reaction was completed, the mixture was washed, rotary evaporated, separated and purified, and precipitated to obtain compound 5; cuprous chloride and tetramethylethylenediamine were added to a reaction tube containing dichloromethane, stirred and mixed, and compound 5 was added to dichloromethane. After mixing, the mixture was added to the reaction tube, heated for reaction, washed, rotary evaporated, separated and purified, and precipitated to obtain an organic active substance; The preparation method of the modified conductive agent comprises the following steps: S1: Cyclohexane, 2-tert-butylphenol, and benzaldehyde are added to a container, diethylamine is added under stirring, the temperature is increased to react, and then heated under reduced pressure for distillation. Subsequently, a mixed solution of anhydrous ethanol and cyclohexane is added to the container, recrystallized, filtered, washed, and dried to obtain intermediate A; S2: Add intermediate A, toluene, and tetracycloheptane to a container, heat with stirring at reflux, and purify by rotary evaporation to obtain a crude product. Add the crude product and sodium sulfate to methanol, heat with stirring under a nitrogen atmosphere, and then concentrate in vacuo. Add ethyl acetate, extract, dry, and filter to obtain intermediate B. S3: Add intermediate B, graphene and tetrahydrofuran to a container, then add Grubbs catalyst, react at room temperature, and after the reaction is completed, dilute and add to methanol, stir to react, filter, vacuum dry, wash, and dry to obtain a modified conductive agent.

2. The method for preparing a lithium battery pack with excellent cycle performance according to claim 1, characterized in that: In the step 1, the amount ratio of polyvinylidene fluoride, N-methylpyrrolidone, organic active substance and modified conductive agent is (1-2) g: (8-12) mL: (5-8) g: (2-3) g, the mixing and grinding time is 10-15 min, and the stirring and mixing time is continued for 4-6 h. First, it is dried at 50-60° C. for 10-12 h, and then vacuum dried at 80-85° C. for 8-10 h. In the step 2, the amount ratio of graphite, carboxymethyl cellulose and deionized water is (3-5) g: (1-2) g: (5-7) mL. In the step 3, the diaphragm is composed of a polypropylene film.

3. The method for preparing a lithium battery pack with excellent cycle performance according to claim 1, characterized in that: In Q1, the amount ratio of tetrachloroperylene anhydride, propionic acid and aminotriglycol monomethyl ether is (8-13) g: (180-220) mL: (9-12) g, the heating and stirring reflux reaction temperature is 130-150° C., and the reaction time is 15-18 h; the amount ratio of compound 1, cuprous iodide, L-proline and dimethyl sulfoxide is (3-6) g: (18-20) g: (11-13) g: (100-130) mL, the heating and stirring reflux reaction temperature is 110-120° C., the stirring speed is 600-800 rpm, the reaction time is 16-20 h, and the stirring mixing time is 1-2 h.

4. The method for preparing a lithium battery pack with excellent cycle performance according to claim 1, characterized in that: In the Q2, the amount ratio of compound 2, bipyraclostrobin, tris(pentafluorophenyl)phosphine, methoxy(cyclooctadiene) iridium polymer and dichlorohexacyclopentane is (1-1.5) g: (3-3.88) g: (0.081-0.086) g: (0.024-0.027) g: (18-25) mL, the heating stirring reflux reaction temperature is 100-120 ° C, the stirring speed is 600-700 rpm, and the reaction time is 10-12h; compound 3, copper bromide, dioxane, methanol, The dosage ratio of triisopropylsilyl acetylene and dimethyl sulfoxide is (1.2-1.8) g: (2.01-2.25) g: (38-42) mL: (14-18) mL: (1.41-1.84) g: (80-120) mL, the heating and stirring reflux reaction temperature is 110-130°C, the stirring speed is 600-800 rpm, the reaction time is 10-12h, the stirring reaction time is 1-2h, the heating and stirring reaction temperature is 110-120°C, and the reaction time is 3-5h.

5. The method for preparing a lithium battery pack with excellent cycle performance according to claim 1, wherein: In Q3, the dosage ratio of compound 4 and tetrabutylammonium fluoride is (0.3-0.5) g: (0.2-0.4) mL, and the closed reaction time is 10-12 h; the dosage ratio of cuprous chloride, tetramethylethylenediamine and compound 5 is (3-5) mg: (10-13) μL: (35-41.2) mg, the heating reaction temperature is 50-60°C, and the reaction time is 6-8 h.

6. The method for preparing a lithium battery pack with excellent cycle performance according to claim 1, characterized in that: In S1, the dosage ratio of cyclohexane, 2-tert-butylphenol, benzaldehyde, diethylamine and the mixed solution is (80-120) mL: (90-110) g: (62-68) g: (5-6) g: (130-135) mL, the temperature of the reaction is 100-120° C., the reaction time is 20-24 h, the temperature of the heating and reduced pressure distillation is 120-125° C., the reduced pressure distillation time is 1-2 h, and the volume ratio of anhydrous ethanol to cyclohexane is 3:

1.

7. The method for preparing a lithium battery pack with excellent cycle performance according to claim 1, characterized in that: In S2, the amount ratio of intermediate A, toluene, and tetracycloheptane is (14-16) g: (40-60) mL: (9-10.2) g, the heating and stirring reflux temperature is 50-65°C, and the reflux time is 72-90 h. The amount ratio of crude product, sodium sulfate, methanol, and ethyl acetate is (6-10) g: (8-8.5) g: (80-120) mL: (90-110) mL, the heating and stirring temperature is 45-55°C, and the stirring time is 4-6 h. In S3, the amount ratio of intermediate B, graphene, tetrahydrofuran, and Grubbs' catalyst is (50-70) mg: (30-40) mg: (2-4) mL: (1.2-1.5) mg, the reaction time at room temperature is 2-4 h, and the stirring reaction time is 1-2 h.

8. A lithium battery pack with excellent cycle performance, characterized in that: Prepared by the method according to any one of claims 1 to 7.

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