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CN-122025843-A - Method for preparing 360 Wh/kg high specific energy semi-solid lithium battery

CN122025843ACN 122025843 ACN122025843 ACN 122025843ACN-122025843-A

Abstract

The invention provides a 360 Wh/kg high-specific-energy semisolid lithium battery preparation method which comprises the following steps of S1, preparing a positive electrode material, S2, preparing a negative electrode material, S3, assembling a lamination, S4, packaging a battery cell, S5, injecting liquid and pre-packaging, injecting semisolid electrolyte into the preliminarily packaged battery cell, vacuum standing, vacuum pre-packaging, S6, forming and ageing, namely performing high-temperature ageing, pressure forming and vacuum secondary sealing on the pre-packaged battery cell, and finishing high-temperature ageing treatment, S7, and performing subsequent treatment. According to the preparation method of the 360 Wh/kg high-specific-energy semi-solid lithium battery, the high-specific-energy semi-solid lithium battery with stable structure and excellent performance can be prepared, the problems of low energy density, poor safety, short cycle life and weak low-temperature performance in the prior art can be overcome, and the practical landing and popularization of the next-generation high-performance battery technology are promoted.

Inventors

  • TANG GUANGBIN
  • LIANG WENLEI
  • LI MUDI
  • ZHOU DONGSHENG

Assignees

  • 河南弘康新能源技术有限公司

Dates

Publication Date
20260512
Application Date
20260123

Claims (9)

  1. 1. A preparation method of a 360 Wh/kg high specific energy semi-solid lithium battery is characterized by comprising the following steps: S1, preparing a positive electrode material, namely uniformly mixing a positive electrode active material, a positive electrode conductive agent and a positive electrode binder according to a mass ratio, carrying out positive electrode batching, and then carrying out positive electrode coating, positive electrode rolling, positive electrode die cutting and positive electrode sheet baking to obtain a positive electrode sheet; s2, preparing a negative electrode material, namely uniformly mixing a negative electrode active material, a negative electrode conductive agent and a negative electrode binder according to a mass ratio, carrying out negative electrode batching, and then carrying out negative electrode coating, negative electrode rolling, negative electrode die cutting and negative electrode sheet baking to obtain a negative electrode sheet; s3, lamination assembly, namely alternately stacking the positive electrode plate and the negative electrode plate, and then carrying out tab welding and tab cutting to form a battery core lamination structure; S4, packaging the battery cell, namely performing high-temperature glue pasting, hot-pressing testing, shell loading, shell punching, top side sealing, short circuit testing, protective film pasting and battery cell baking on a battery cell lamination structure to finish primary packaging of the battery cell; s5, injecting liquid and pre-sealing, namely injecting semi-solid electrolyte into the preliminarily packaged battery cell, carrying out vacuum standing, and then carrying out vacuum pre-sealing; s6, formation and aging, namely performing high-temperature aging, pressure formation and vacuum secondary sealing on the pre-sealed battery cell to finish high-temperature aging treatment; s7, carrying out subsequent treatment, namely cutting, folding and scalding, primary standing, capacity division, secondary standing, OCV testing, matching and warehousing on the battery core subjected to high-temperature aging to obtain the 360 Wh/kg high-specific-energy semi-solid lithium battery.
  2. 2. The method for preparing a 360 Wh/kg high-specific-energy semi-solid lithium battery as claimed in claim 1, wherein the positive electrode active material is nickel cobalt lithium manganate or nickel cobalt lithium aluminate, and the nickel content is not less than 85%.
  3. 3. The method for preparing a 360 Wh/kg high specific energy semisolid lithium battery according to claim 1, wherein the negative electrode active material is a silicon-carbon composite material, wherein the silicon content is 10-20 wt%, and the carbon matrix is graphite or hard carbon.
  4. 4. The method for preparing a 360 Wh/kg high-specific-energy semisolid lithium battery according to claim 1, wherein the positive electrode binder is a complex of polyvinylidene fluoride or sodium carboxymethyl cellulose and styrene-butadiene rubber, and the negative electrode binder is a complex of polyvinylidene fluoride or sodium carboxymethyl cellulose and styrene-butadiene rubber.
  5. 5. The method for preparing a 360 Wh/kg high specific energy semisolid lithium battery according to claim 1, wherein the positive electrode coating thickness is 80-120 μm, the negative electrode coating thickness is 60-100 μm, and the pole piece compaction densities after rolling are 3.5-3.9 g/cm3 and 1.6-1.8 g/cm respectively.
  6. 6. The method for preparing a 360 Wh/kg high-specific-energy semi-solid lithium battery according to claim 1, wherein the semi-solid electrolyte consists of solid electrolyte particles and liquid electrolyte, wherein the solid electrolyte particles are oxide or sulfide, the mass ratio of the solid electrolyte particles is 30-50%, the liquid electrolyte is a mixture of a carbonate solvent and a lithium salt, and the lithium salt is lithium hexafluorophosphate or lithium difluorooxalato borate.
  7. 7. The method for preparing the 360 Wh/kg high-specific-energy semi-solid lithium battery according to claim 6, wherein the injection process of the semi-solid electrolyte is performed in a vacuum environment, the vacuum degree is-0.09 to-0.1 MPa, the injection amount is controlled to be 95-105% of a theoretical value, the pressure formation step is to charge to a cut-off voltage by constant current, then charge to current by constant voltage and reduce to 0.05C, the formation temperature is 45-60 ℃ and the formation time is not less than 4 hours, the high-temperature aging treatment temperature is 60-80 ℃ and the duration is 24-72 hours, the battery cell package adopts an aluminum plastic film soft package structure, and the aluminum plastic film has a three-layer composite structure comprising an outer nylon layer, a middle aluminum foil layer and an inner polypropylene layer.
  8. 8. The method for preparing a 360 Wh/kg high specific energy semi-solid lithium battery according to claim 1 or 7, wherein the positive electrode conductive agent is at least one of conductive carbon black, conductive graphite or carbon nanotubes, the negative electrode conductive agent is carbon nanotubes or graphene, the addition amount is 0.05-0.2-wt% of the total mass of the negative electrode, the baking temperature of the negative electrode sheet is 120-150 ℃, the time is 4-8 hours, the environmental dew point is not higher than-40 ℃, the baking temperature of the positive electrode sheet is 180-200 ℃, the time is 6-10 hours, and the environmental dew point is not higher than-50 ℃ so as to sufficiently remove moisture and stabilize the electrode structure.
  9. 9. The method for preparing the 360 Wh/kg high specific energy semi-solid lithium battery according to claim 1, wherein the protective film is a ceramic coating diaphragm, the coating material is alumina or silicon dioxide, the thickness is 2-3 mu m, the base film is polyethylene or porous PET composite film, the total thickness is 9-12 mu m, the diaphragm covers the edges of the positive and negative plates in the lamination process, and the insulation safety of the inside of the battery core is ensured.

Description

Method for preparing 360 Wh/kg high specific energy semi-solid lithium battery Technical Field The invention belongs to the technical field, and particularly relates to a preparation method of a 360 Wh/kg high-specific-energy semi-solid lithium battery. Background With the development of electric automobiles, unmanned aerial vehicles and intelligent devices, the requirements on battery energy density, safety and environmental adaptability are increasingly increasing. The traditional lithium ion battery is limited by liquid electrolyte and electrode materials, has the problems of low energy density (generally 200-280 Wh/kg), flammability and explosiveness, short cycle life and poor low-temperature performance, and is difficult to meet the high-end application requirements. In particular, under high-rate discharge and low-temperature environments, the conventional battery has significant capacity degradation and increased safety risks. To break through the bottleneck, semi-solid lithium batteries have become an important development direction. The solid or gel electrolyte is adopted, so that lithium dendrite can be restrained, the thermal stability is improved, and the lithium dendrite is compatible with high specific volume positive and negative electrode materials (such as high nickel ternary and high silicon negative electrode), so that higher energy density and better safety are expected to be realized. However, the existing semi-solid battery still faces the challenges of large interface impedance, complex process, high cost and the like. Therefore, a semisolid lithium battery which has high energy density of 360 Wh/kg, long cycle life (500-1000 times), good low-temperature performance (-20 ℃ to 0 ℃ usable) and can be prepared in a large scale is developed, and the semisolid lithium battery has important practical significance and industrial value. Disclosure of Invention In view of the defects in the prior art, the invention provides a method for preparing a 360 Wh/kg high-specific-energy semi-solid lithium battery, which not only can prepare the high-specific-energy semi-solid lithium battery with stable structure and excellent performance, but also can overcome the problems of low energy density, poor safety, short cycle life and weak low-temperature performance in the prior art, and promote the practical landing and popularization of the next-generation high-performance battery technology. In order to solve the technical problems, the technical scheme adopted by the invention is that the preparation method of the 360 Wh/kg high-specific-energy semi-solid lithium battery comprises the following steps: S1, preparing a positive electrode material, namely uniformly mixing a positive electrode active material, a positive electrode conductive agent and a positive electrode binder according to a mass ratio, carrying out positive electrode batching, and then carrying out positive electrode coating, positive electrode rolling, positive electrode die cutting and positive electrode sheet baking to obtain a positive electrode sheet; s2, preparing a negative electrode material, namely uniformly mixing a negative electrode active material, a negative electrode conductive agent and a negative electrode binder according to a mass ratio, carrying out negative electrode batching, and then carrying out negative electrode coating, negative electrode rolling, negative electrode die cutting and negative electrode sheet baking to obtain a negative electrode sheet; s3, lamination assembly, namely alternately stacking the positive electrode plate and the negative electrode plate, and then carrying out tab welding and tab cutting to form a battery core lamination structure; S4, packaging the battery cell, namely performing high-temperature glue pasting, hot-pressing testing, shell loading, shell punching, top side sealing, short circuit testing, protective film pasting and battery cell baking on a battery cell lamination structure to finish primary packaging of the battery cell; s5, injecting liquid and pre-sealing, namely injecting semi-solid electrolyte into the preliminarily packaged battery cell, carrying out vacuum standing, and then carrying out vacuum pre-sealing; s6, formation and aging, namely performing high-temperature aging, pressure formation and vacuum secondary sealing on the pre-sealed battery cell to finish high-temperature aging treatment; s7, carrying out subsequent treatment, namely cutting, folding and scalding, primary standing, capacity division, secondary standing, OCV testing, matching and warehousing on the battery core subjected to high-temperature aging to obtain the 360 Wh/kg high-specific-energy semi-solid lithium battery. As a further improvement of the present invention, the positive electrode active material is lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminate, and the nickel content is not less than 85%. As a further improvement of the present invention, the negative el