A quasi-solid-state lithium ion battery and a preparation process thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 江苏国轩新能源科技有限公司
- Filing Date
- 2026-05-19
- Publication Date
- 2026-08-07
AI Technical Summary
[0005]为了减少准固态电解质固化工艺参数模糊、固化过程体积膨胀导致界面接触恶化、以及与现有产线适配性差等技术缺陷，本申请提供一种准固态锂离子电池及制备工艺
1、本申请通过采用特定的拘束压力和注液系数组合，有效控制了极片厚度增长，确保了电极与电解质间的紧密接触，大幅降低界面阻抗。有效解决了准固态电解质固化过程中的体积膨胀及界面接触问题，显著提升了电池的首周库伦效率、倍率性能及循环稳定性。
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Abstract
Description
Technical Field
[0001] This invention relates to the technical field of lithium batteries, and in particular to a quasi-solid-state lithium-ion battery and its preparation process. Background Technology
[0002] With the global energy structure transformation, lithium-ion batteries have been widely used in new energy vehicles, consumer electronics, and energy storage due to their advantages such as high energy density and long cycle life. However, traditional commercial lithium-ion batteries generally use liquid organic electrolytes, which pose safety hazards such as volatility, leakage, and flammability, limiting their application in extreme environments.
[0003] While solid-state electrolytes can significantly improve battery safety and broaden the operating temperature window, their high interfacial impedance and poor compatibility with existing production lines have hindered their commercialization. Polymer quasi-solid-state electrolytes combine the high ionic conductivity of liquid electrolytes with the safety of solid electrolytes, and also possess good mechanical flexibility and ease of processing, making them a highly promising next-generation battery material.
[0004] Currently, the core challenge in the transition from laboratory to mass production of quasi-solid-state electrolytes is the lack of clear in-situ curing process parameters. The selection of parameters such as curing temperature, time, and pressure directly affects the completeness of the polymerization reaction, the control of volume expansion, and the interfacial contact state, thus impacting the final electrochemical performance of the battery. Furthermore, in existing quasi-solid-state battery fabrication methods, the liquid injection coefficient is often directly adopted from the parameters of liquid electrolytes, leading to uneven pressure on the electrodes and increased internal resistance after curing due to volume expansion. Therefore, developing a stable, parameter-controllable, and compatible quasi-solid-state battery fabrication process is a pressing technical problem that the industry needs to solve. Summary of the Invention
[0005] To reduce technical defects such as ambiguous curing process parameters for quasi-solid electrolytes, deterioration of interfacial contact due to volume expansion during curing, and poor compatibility with existing production lines, this application provides a quasi-solid lithium-ion battery and its preparation process.
[0006] Firstly, the fabrication process of a quasi-solid-state lithium-ion battery provided in this application adopts the following technical solution: A fabrication process for a quasi-solid-state lithium-ion battery includes the following steps: Under an inert atmosphere and a dew point ≤-60℃, lithium salt and plasticizer are mixed evenly to obtain a basic electrolyte. Polymer monomers and thermal initiators are added to the basic electrolyte and stirred until completely dissolved to obtain a quasi-solid electrolyte precursor solution. The quasi-solid electrolyte precursor solution is injected into the battery cell for wetting; the injection coefficient of the quasi-solid electrolyte precursor solution is 1.8-2.3 g / Ah. The impregnated cells are subjected to in-situ thermal curing with the following parameters: temperature 35-45℃, time 40-48h, and a restraint pressure of 0.1-0.3MPa is applied during the in-situ thermal curing process. The cured cells are then subjected to formation and capacity testing to obtain a quasi-solid-state lithium-ion battery.
[0007] In one specific implementation, the polymer monomer is polyethylene glycol diacrylate.
[0008] In one specific implementation, the thermal initiator is azobisisobutyronitrile (AIBN).
[0009] In one specific implementation, the lithium salt comprises lithium bis(trifluoromethanesulfonyl)imide and lithium hexafluorophosphate, wherein lithium hexafluorophosphate accounts for 1-2% of the total mass of the lithium salt.
[0010] In one specific implementation, the plasticizer comprises ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7.
[0011] In one specific implementation, the current collector surface of the positive electrode is provided with an LATP ceramic layer with a thickness of 5-8 μm.
[0012] In one specific implementation, the chemical formula of the LATP ceramic is Li. 1.3 Al 0.3 Ti 1.7 (PO4)3.
[0013] In one specific implementation, the negative electrode active material in the negative electrode sheet includes a graphite and silicon-carbon composite material, wherein the silicon-carbon composite material accounts for 14-20% of the total mass of the negative electrode active material.
[0014] Secondly, the quasi-solid-state lithium-ion battery provided in this application adopts the following technical solution: A quasi-solid-state lithium-ion battery is prepared using the aforementioned quasi-solid-state lithium-ion battery preparation process.
[0015] In one specific implementation, the quasi-solid-state lithium-ion battery has a first-cycle coulombic efficiency of ≥86.4% in the voltage range of 2.5-4.3V and a DC internal resistance of ≤3.67mΩ at 50% SOC.
[0016] In summary, this application has the following beneficial effects: 1. This application effectively controls the electrode thickness growth by employing a specific combination of restraint pressure and electrolyte injection coefficient, ensuring close contact between the electrode and electrolyte and significantly reducing interfacial impedance. It effectively solves the volume expansion and interfacial contact problems during the solidification process of quasi-solid electrolytes, significantly improving the battery's first-cycle coulombic efficiency, rate performance, and cycle stability.
[0017] 2. In this application, it is preferred to introduce an LATP ceramic coating on the surface of the positive electrode to increase the lithium-ion transport channels and stabilize the positive electrode structure.
[0018] 3. The curing temperature selected in this application is compatible with the baking and aging process temperatures in existing battery production, eliminating the need for large-scale production line modifications and facilitating rapid mass production. Attached Figure Description
[0019] Figure 1 This is a diagram showing the state of the electrolyte in Comparative Example 1 after 48 hours of heating and curing.
[0020] Figure 2 This is a diagram showing the state of the electrolyte in Comparative Example 2 after 48 hours of heating and curing. Detailed Implementation
[0021] Unless otherwise specified, all raw materials used in this application were commercially available. Polyethylene glycol diacrylate (CAS: 26570-48-9) was purchased from Hefei Qianrui Technology Co., Ltd. Azobisisobutyronitrile (CAS: 78-67-1) was purchased from Hefei Qianrui Technology Co., Ltd. Lithium bis(trifluoromethanesulfonyl)imide (CAS: 90076-65-6) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Lithium hexafluorophosphate (CAS: 21324-40-3) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Ethylene carbonate (CAS: 96-49-1) was purchased from Hefei Qianrui Technology Co., Ltd. Ethyl methyl carbonate (CAS: 623-53-0) was purchased from Hefei Qianrui Technology Co., Ltd.
[0022] The present application will be further described in detail below with reference to embodiments and comparative examples.
[0023] Example Example 1
[0024] This embodiment provides a fabrication process for a quasi-solid-state lithium-ion battery, including the following steps: Under an inert atmosphere and at a dew point ≤ -60℃, 18 kg of lithium salt and 55 kg of plasticizer were mixed evenly to obtain a basic electrolyte. 25 kg of polyethylene glycol diacrylate and 0.3 kg of azobisisobutyronitrile were then added to the basic electrolyte and stirred until completely dissolved to obtain a quasi-solid-state electrolyte precursor solution. The lithium salt comprised the following components by mass percentage: 98.5% lithium bis(trifluoromethanesulfonyl)imide and 1.5% lithium hexafluorophosphate. The plasticizer comprised ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7.
[0025] The conductive agent (EX671D, 9% solid content, Tiannai) and ternary lithium Ni78 (LiNi) were added. x Co y Mn zO2 (x+y+z=1) and binder (BV-SW-5130, Finoline) are added to a kneader at a mass ratio of 1.12:97.88:1. After gluing, kneading, and high-speed dispersion, N-methylpyrrolidone is added to adjust the viscosity to between 3000-7000 mPa·s, resulting in a positive electrode slurry with a fineness ≤30μm. The positive electrode slurry is then coated on both sides of an aluminum foil. After drying, it is transferred to a die head to coat a 6μm thick LATP ceramic layer. Following drying, rolling, and die-cutting, the positive electrode sheet is obtained. The chemical formula of LATP ceramic is Li. 1.3 Al 0.3 Ti 1.7 (PO4)3.
[0026] Graphite (NG-XFH3, Xiangfenghua), silicon-carbon composite material (S0310, Lanxi Zhide), conductive agent (Li-2060, Hexing Chemical), binder (2500C, Weiyi Technology), and thickener (GD1346L, Daoying) were added to a kneader in a mass ratio of 74.46:18.04:2:3.7:1.8. After kneading and high-speed dispersion, water was added to adjust the slurry viscosity to the range of 3000-10000 mPa·s, resulting in a negative electrode slurry with a fineness ≤40μm. The negative electrode slurry was then coated on both sides of a copper foil, and after drying, rolling, and die-cutting, a negative electrode sheet with a thickness of 120.1±3μm was obtained.
[0027] The positive and negative electrode sheets were tested for moisture content. The moisture content of both positive and negative electrode sheets was ≤500ppm. If the moisture content was not up to standard, the electrode rolls were baked until they met the standard, and then rolled and die-cut. The positive electrode sheet, separator, and negative electrode sheet were sequentially stacked, hot-pressed and shaped, with tabs welded, encapsulated in an aluminum-plastic film, and baked to obtain the battery cell.
[0028] Under an inert atmosphere and with a dew point ≤-60℃, the quasi-solid electrolyte precursor solution was injected into the battery cell. After injection, the negative pressure was maintained for 5 minutes, and then the battery cell was transferred to a constant temperature chamber at 25℃±2℃ and left to stand for 24 hours to complete the wetting process. The injection coefficient of the quasi-solid electrolyte precursor solution was 1.8 g / Ah.
[0029] The impregnated battery cells were subjected to in-situ thermosetting with the following parameters: temperature 52℃, time 44h, and a restraint pressure of 0MPa applied during the in-situ thermosetting process. The cured battery cells were then subjected to formation and capacity testing to obtain quasi-solid-state lithium-ion batteries.
[0030] Example 2-12
[0031] The only difference between Examples 2-12 and Example 1 is the injection coefficient and the restraint pressure applied during the in-situ thermosetting process. The injection coefficient and the restraint pressure applied during the in-situ thermosetting process of Examples 2-12 are shown in Table 1.
[0032] Table 1 Example 13
[0033] The only difference between this embodiment and Embodiment 1 is that a restraint pressure of 0.3 MPa is applied during the in-situ thermosetting process.
[0034] Example 14
[0035] The only difference between this embodiment and Embodiment 1 is that a restraint pressure of 0.4 MPa is applied during the in-situ thermosetting process.
[0036] Example 15
[0037] The only difference between this embodiment and Embodiment 1 is that the in-situ thermosetting temperature is 35°C.
[0038] Example 16
[0039] The only difference between this embodiment and Embodiment 1 is that the in-situ thermosetting temperature is 45°C.
[0040] Example 17
[0041] The only difference between this embodiment and Embodiment 1 is that the in-situ thermosetting time is 40 hours.
[0042] Example 18
[0043] The only difference between this embodiment and Embodiment 1 is that the in-situ thermosetting time is 48 hours.
[0044] Example 19
[0045] The only difference between this embodiment and Example 1 is that the lithium salt comprises the following components by mass percentage: 99% lithium bis(trifluoromethanesulfonyl)imide and 1% lithium hexafluorophosphate.
[0046] Example 20
[0047] The only difference between this embodiment and Example 1 is that the lithium salt comprises the following components by mass percentage: 98% lithium bis(trifluoromethanesulfonyl)imide and 2% lithium hexafluorophosphate.
[0048] Example 21
[0049] The only difference between this embodiment and Embodiment 1 is that positive electrode slurry is coated on both sides of the aluminum foil, dried, and then transferred to the die head to coat a 5μm thick LATP ceramic layer. After drying, rolling, and die cutting, the positive electrode sheet is obtained.
[0050] Example 22
[0051] The only difference between this embodiment and Embodiment 1 is that positive electrode slurry is coated on both sides of the aluminum foil, dried, and then transferred to the die head to coat an 8μm thick LATP ceramic layer. After drying, rolling, and die cutting, the positive electrode sheet is obtained.
[0052] Example 23
[0053] The only difference between this embodiment and Embodiment 1 is that graphite, silicon-carbon composite material, conductive agent, binder, and thickener are added to a kneader in a mass ratio of 86:14:2:3.7:1.8. After kneading and high-speed dispersion, water is added to adjust the viscosity of the slurry to the range of 3000-10000 mPa·s, resulting in a negative electrode slurry with a fineness ≤40μm.
[0054] Example 24
[0055] The only difference between this embodiment and Embodiment 1 is that graphite, silicon-carbon composite material, conductive agent, binder, and thickener are added to a kneader in a mass ratio of 80:20:2:3.7:1.8. After kneading and high-speed dispersion, water is added to adjust the slurry viscosity to the range of 3000-10000 mPa·s, resulting in a negative electrode slurry with a fineness ≤40μm.
[0056] Comparative Example 1 Under an inert atmosphere and at a dew point ≤ -60℃, 18 kg of lithium salt and 55 kg of plasticizer were mixed evenly to obtain a basic electrolyte. 25 kg of polyethylene glycol diacrylate and 0.3 kg of azobisisobutyronitrile were then added to the basic electrolyte and stirred until completely dissolved to obtain a quasi-solid-state electrolyte precursor solution. The lithium salt comprised the following components by mass percentage: 98.5% lithium bis(trifluoromethanesulfonyl)imide and 1.5% lithium hexafluorophosphate. The plasticizer comprised ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7.
[0057] The quasi-solid electrolyte precursor solution was injected into a self-made aluminum-plastic film sealing bag and then vacuum-sealed. The initial volume was then measured using the water displacement method and recorded as 0h. The bag was then transferred to a 45℃ oven, and the volume changes were recorded at 18h, 24h, 40h, 48h, and 60h.
[0058] Comparative Example 2 The preparation process of Comparative Example 2 is the same as that of Comparative Example 1, except that Comparative Example 2 is transferred to a 60°C oven.
[0059] Table 2 shows the volume data recorded for Comparative Examples 1-2 at 0h, 18h, 24h, 40h, 48h, and 60h.
[0060] Table 2 Performance testing For Examples 1-24, the following performance tests were performed: The quasi-solid-state lithium-ion batteries prepared in Examples 1-12 were disassembled and the electrode thickness and residual electrolyte volume were measured. The test data are shown in Table 3.
[0061] The quasi-solid-state lithium-ion batteries prepared in Examples 1-24 were subjected to room temperature formation, aging, and capacity testing. The designed capacity was 10 Ah. After the tests, the first-cycle charge-discharge capacity, specific capacity, first-cycle charge-discharge efficiency, and DCIR at 50% SOC were recorded within a voltage range of 2.5-4.3V. The test results are shown in Table 4.
[0062] Table 3 Table 4 Combining Comparative Examples 1-2 and Table 1-2, it can be seen that, according to the water displacement method, the volume of Comparative Examples 1 and 2 increased gradually with the solidification of the electrolyte at different time periods, reaching over 90% solidification within 40-48 hours. Furthermore, the remaining initiator may deactivate with prolonged time, so the time should be controlled within 48 hours. Additionally, in Comparative Example 2, the volume expansion rate was faster, and the initiator was more prone to failure at this temperature. Figure 1 and Figure 2 It can be seen that, Figure 2 The residual amount of electrolyte liquid was relatively large, which actually prevented it from being effective. Figure 1 The curing temperature was good at 45℃, and the electrolyte had already shown signs of yellowing. Therefore, the curing temperature was determined to be 45℃, and the time was set at 40-48 hours to ensure that the polymer electrolyte achieved optimal curing results through in-situ polymerization.
[0063] Combining Examples 1-24 with Table 1, it can be seen that under different restraint pressures and with different injected electrolyte masses, the degree of expansion during the curing process is not entirely consistent, resulting in different electrode thicknesses and different amounts of residual electrolyte. Specifically, regarding the electrode thicknesses between the three groups of injection coefficients in Examples 1-4, 5-8, and 9-12, it can be seen that insufficient injection volume does not result in thinner thickness. This may be because when the electrolyte is insufficient, local wetting is poor, leading to excessive thickness in the electrode pores, which is confirmed by the minimum amount of residual electrolyte. Furthermore, under different restraint pressures, the amount of electrolyte wetting into the electrode pores varies, thus resulting in differences in thickness during the subsequent curing process. A comparison within the two groups of Examples 5-8 and 9-12 shows that the electrode thickness is not significantly different when there is no restraint and when the restraint pressure is 0.2 MPa, while the electrode thickness is relatively smaller when the restraint pressure is 0.05 MPa and 0.1 MPa. Therefore, given a certain expansion coefficient, the injection coefficient cannot be directly referenced from the injection coefficient of liquid electrolyte; furthermore, in order to achieve a better wetting effect, while avoiding excessive expansion during the electrolyte solidification process.
[0064] According to the formation and capacity testing data of the pouch batteries in Examples 1-12 in Table 4, the lowest capacity performance among the three groups of electrolyte injection coefficients (Examples 1-4, 5-8, and 9-12) is actually achieved with the largest electrolyte injection volume. This is likely because the excess electrolyte, after solidification, lies between the separator and the electrode, resulting in a longer lithium-ion transport path and capacity loss in other forms. When comparing the DCIR data at 50% SOC, it can be seen that the overall resistance of Examples 1-4 is higher, which is consistent with the results of electrode thickness measurements after battery disassembly following solidification. The significant increase in thickness during solidification leads to an overall increase in the battery's internal resistance. Furthermore, in Examples 5-8, Example 7 exhibits the highest charge and discharge capacity, a higher first-cycle coulombic efficiency, and slightly lower internal resistance than Example 6.
[0065] In summary, it was verified that the curing process of the quasi-solid-state electrolyte should be carried out at 45℃ for 40-48 hours, with an injection coefficient of 2.0 g / Ah and a restraint pressure of about 0.1 MPa, resulting in a good electrolyte curing state and optimal performance in terms of first-cycle charge-discharge capacity, first-cycle efficiency, and internal resistance during the formation and capacity testing. The determination of these manufacturing process parameters or ranges provides strong support for leveraging the superior performance of quasi-solid-state electrolyte lithium-ion batteries.
[0066] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A fabrication process for a quasi-solid-state lithium-ion battery, characterized in that, Includes the following steps: Under an inert atmosphere and a dew point ≤-60℃, lithium salt and plasticizer are mixed evenly to obtain a basic electrolyte. Polymer monomers and thermal initiators are added to the basic electrolyte and stirred until completely dissolved to obtain a quasi-solid electrolyte precursor solution. The quasi-solid electrolyte precursor solution is injected into the battery cell for wetting; the injection coefficient of the quasi-solid electrolyte precursor solution is 1.8-2.3 g / Ah. The impregnated cells are subjected to in-situ thermal curing with the following parameters: temperature 35-45℃, time 40-48h, and a restraint pressure of 0.1-0.3MPa is applied during the in-situ thermal curing process. The cured cells are then subjected to formation and capacity testing to obtain a quasi-solid-state lithium-ion battery.
2. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 1, characterized in that, The polymer monomer is polyethylene glycol diacrylate.
3. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 2, characterized in that, The thermal initiator is azobisisobutyronitrile.
4. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 1, characterized in that, The lithium salt includes lithium bis(trifluoromethanesulfonyl)imide and lithium hexafluorophosphate, wherein lithium hexafluorophosphate accounts for 1-2% of the total mass of the lithium salt.
5. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 1, characterized in that, The plasticizer comprises ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:
7.
6. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 1, characterized in that, The current collector surface of the positive electrode is provided with an LATP ceramic layer with a thickness of 5-8 μm.
7. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 6, characterized in that, The chemical formula of the LATP ceramic is Li 1.3 Al 0.3 Ti 1.7 (PO4)3.
8. The fabrication process of the quasi-solid-state lithium-ion battery according to claim 1, characterized in that, The negative electrode active material in the negative electrode sheet includes graphite and silicon-carbon composite material, wherein the silicon-carbon composite material accounts for 14-20% of the total mass of the negative electrode active material.
9. A quasi-solid-state lithium-ion battery, characterized in that, It is prepared using the quasi-solid-state lithium-ion battery preparation process described in any one of claims 1-8.
10. The quasi-solid-state lithium-ion battery according to claim 9, characterized in that, The quasi-solid-state lithium-ion battery has a first-cycle coulombic efficiency of ≥86.4% in the voltage range of 2.5-4.3V and a DC internal resistance of ≤3.67mΩ at 50% SOC.