A semi-solid battery in-situ solidification method and semi-solid battery
By employing a phased impregnation and curing method, the problems of impregnation difficulties and uneven curing in semi-solid batteries were solved, thereby improving the electrochemical performance and safety of the batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING ELECTRIC VEHICLE
- Filing Date
- 2026-03-30
- Publication Date
- 2026-07-07
AI Technical Summary
In existing technologies, the difficulty in wetting and uneven curing of semi-solid batteries leads to poor electrochemical performance and safety.
A phased impregnation and curing method is adopted, including high-temperature impregnation, low-temperature impregnation, and phased curing processes. By controlling temperature and pressure, the electrolyte is ensured to penetrate evenly and form a uniform gel network structure.
This achieves uniform penetration of the electrolyte inside the cell, improving the wetting effect and structural stability of the cell, and enhancing the cycle life, capacity retention, and safety performance of the battery.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery material technology, and more specifically, relates to an in-situ curing method for semi-solid batteries and a semi-solid battery. Background Technology
[0002] With the development of battery cell technology, improving energy density and safety has become increasingly important, and semi-solid-state batteries using polymer solid electrolytes are one such approach. To obtain polymer solid electrolytes, an in-situ solidification process is typically used. Specifically, in existing technologies, in-situ solidification usually involves injecting the electrolyte, monomers, and initiator into the battery cell at once before formation, followed by room-temperature wetting. Then, external conditions such as heating are applied to trigger the decomposition of the initiator, thereby in-situ polymerization to form a gel. This method has significant drawbacks: Firstly, due to the introduction of monomers, the electrolyte has a high viscosity at room temperature, making it difficult to quickly penetrate into the micropores of the battery cell electrodes and the gaps in the separator, easily leading to poor wetting and localized dry areas. Secondly, because the initiator is present simultaneously with the monomers and electrolyte, the solidification reaction may be prematurely triggered during wetting, forming localized gel blocks that hinder further diffusion of the electrolyte and severely affect the overall wetting uniformity of the battery cell, resulting in wetting difficulties.
[0003] Furthermore, the maximum pressure and temperature are typically applied directly to the battery cell during the curing stage. This forces the already impregnated electrolyte out of the cell, disrupting the impregnation state (i.e., the electrolyte in the separator and electrode pores is forced to the edges and surface, resulting in: more electrolyte, faster polymerization, more cross-linking, and thicker curing at the edges / surface; less electrolyte, slower polymerization, less cross-linking, or even no curing at the interior / deep within the electrode), leading to uneven curing. In addition, the instantaneous high temperature and pressure can cause the initiator to decompose rapidly, triggering a violent polymerization reaction. The large amount of heat generated may cause localized overheating, inducing side reactions, generating unnecessary impurities, and affecting the battery's electrochemical performance and safety.
[0004] Therefore, in order to solve the problems of difficult wetting, uneven curing, and poor electrochemical performance and safety of batteries, it is urgent to propose a new in-situ curing method for semi-solid batteries. Summary of the Invention
[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an in-situ curing method for semi-solid-state batteries and a semi-solid-state battery itself. This invention improves curing uniformity, optimizes the structure of the cured gel, and enhances cell performance by controlling the wetting and curing conditions in stages.
[0006] To achieve the above objectives, the present invention provides an in-situ solidification method for semi-solid batteries, the method comprising the following steps: S1: Mix the polymer monomer with the electrolyte to form a gel precursor liquid 1; mix the initiator with the electrolyte to form a gel precursor liquid 2; inject the gel precursor liquid 1 into the battery cell for high-temperature impregnation; S2: Inject the gel precursor liquid 2 into the battery cell after it has been impregnated in the high-temperature stage, and then perform impregnation in the medium-temperature stage and the low-temperature stage in sequence. S3: The cells that have been immersed in the low-temperature stage are sequentially cured under low-temperature and low-pressure conditions, medium-temperature and medium-pressure conditions, and high-temperature and high-pressure conditions to obtain a semi-solid-state battery.
[0007] In this invention, the polymerizing monomer is a carbonate organic reactive monomer and / or an acrylate organic reactive monomer, preferably at least one of pentaerythritol tetraacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, 2-bromoethyl acrylate, hydroxypropyl acrylate, isostearyl acrylate, isobutyl methacrylate, 4-hydroxybutyl acrylate, tributyltin acrylate, propane-1,3-yl diacrylate, 4-ethylphenyl acrylate, hydroxyethyl acrylate, diallyl carbonate, propane trimethylol acrylate, and butyl methacrylate.
[0008] In this invention, the initiator is an azo initiator and / or a peroxide initiator, preferably at least one of azobisisobutyronitrile, dicumyl peroxide and benzoyl peroxide.
[0009] In this invention, the polymeric monomer accounts for 0.01-1% of the mass percentage of the gel precursor solution 1. In the gel precursor solution 2, the initiator accounts for 0.5-10% of the mass percentage of the gel precursor solution 2.
[0010] This invention changes the electrolyte injection and curing processes of the battery cell from a conventional one-time process to a multi-stage process, specifically: (1) High-temperature wetting: The high-temperature environment significantly reduces the viscosity and surface tension of the gel precursor liquid 1 and increases the diffusion coefficient, allowing the gel precursor liquid 1 to penetrate more easily into the micropores and membrane gaps of the battery cell electrode sheet, thus significantly accelerating the wetting rate. Simultaneously, the pores inside the electrode material gradually expand with increasing temperature, providing more space for further penetration of the gel precursor liquid 1. Furthermore, no initiator is introduced into the high-temperature injection (gel precursor liquid 1), therefore, the high-temperature wetting of this invention will not trigger a curing reaction; The medium-temperature and low-temperature wetting stages allow the electrode material to gradually adapt to the electrolyte environment, reducing problems such as expansion or contraction of the electrode material caused by excessive temperature differences, thus laying the foundation for the subsequent wetting process. After adding the initiator to the gel precursor solution 2, the staged cooling wetting strategy can both prolong the electrolyte penetration process and control the initiator activity by utilizing temperature stages. Specifically, medium-temperature wetting (e.g., 35℃) can promote the uniform diffusion of the remaining electrolyte, while low-temperature wetting (e.g., 25℃) can delay the start of the curing reaction, ensuring that the electrolyte achieves all-round wetting inside the cell before entering the curing process, avoiding wetting dead zones caused by premature local curing.
[0011] (2) Stage-controlled curing process to achieve a more uniform and stable gel network structure. Specifically, staged curing involves reacting in stages at different temperatures and pressures. First, slight polymerization is triggered at low temperature and low pressure to form a preliminary gel network; then, the temperature and pressure are gradually increased to accelerate the reaction and allow the gel network to gradually densify; finally, the cross-linking reaction is completed under high temperature and high pressure to form a stable gel. This staged approach can effectively avoid local overheating or side reactions caused by excessively rapid reaction, while allowing the polymerization reaction to complete gradually, reducing defects, improving the uniformity and performance of the final product, thereby enhancing the interfacial stability and mechanical strength of the semi-solid-state battery; specifically: Low-temperature and low-pressure curing allows the initiator to diffuse slowly and initiate initial curing, avoiding excessively violent local reactions that can generate bubbles. Medium-temperature and medium-pressure curing can accelerate the curing process, while pressure promotes the densification of the internal structure of the battery cell. High temperature and high pressure curing can ensure complete curing reaction and improve the bonding strength between electrolyte and electrode interface; The staged curing process significantly reduces the internal resistance of semi-solid batteries by balancing reaction rate and structural stability, thereby improving cycle life and safety performance.
[0012] According to the present invention, preferably, the amount of electrolyte in the gel precursor solution 1 is x% by weight, and the amount of electrolyte in the gel precursor solution 2 is (100-x)% by weight, based on the total weight of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2.
[0013] According to the present invention, preferably, the amount of electrolyte in the gel precursor solution 1 is 80-90% by weight and the amount of electrolyte in the gel precursor solution 2 is 10-20% by weight, based on the total weight of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2.
[0014] According to the present invention, preferably, the immersion temperature in the high-temperature stage is ≥45°C and the time is 30-42h.
[0015] According to the present invention, preferably, the temperature of the intermediate temperature stage of immersion is 32-40°C and the time is 3-9 hours.
[0016] According to the present invention, preferably, the immersion temperature in the low-temperature stage is 20-28°C and the time is 3-9 hours.
[0017] According to the present invention, preferably, the low-temperature and low-pressure curing temperature is 30-40°C, the pressure is 150-250N, and the time is 0.3-0.8h.
[0018] According to the present invention, preferably, the curing temperature under medium temperature and medium pressure conditions is 42-50°C, the pressure is 450-550N, and the time is 0.3-0.8h.
[0019] According to the present invention, preferably, the high temperature and high pressure curing conditions are 70-80°C, 700-800N, and 1-2h.
[0020] In another aspect, the present invention provides a semi-solid battery prepared by the aforementioned in-situ solidification method.
[0021] The beneficial effects of the technical solution of the present invention are as follows: The in-situ curing method for semi-solid batteries of the present invention improves curing uniformity, optimizes the structure of the cured gel, and enhances cell performance by controlling the wetting and curing conditions (liquid injection volume, liquid injection temperature, curing temperature, curing pressure, and curing time) in stages.
[0022] The method of this invention employs a multi-step, staged electrolyte injection strategy during the pre-formation electrolyte injection and wetting process, combined with staged temperature control, to achieve layered electrolyte penetration. This allows the electrolyte to penetrate more evenly and fully into the pores inside the battery cell, precisely matching the pore characteristics of different areas within the battery cell, avoiding localized liquid accumulation or insufficient wetting, and ensuring full contact between the electrolyte and electrode materials, thus achieving thorough wetting and laying a solid foundation for subsequent chemical reactions and charge transfer.
[0023] During the curing process, the method of this invention effectively controls the reaction rate and product structure through a staged pressurization and heating synergistic control mode, avoiding the violent polymerization reaction caused by the decomposition of a large amount of initiator at once, reducing the stress and defect formation inside the system, making the polymerization reaction more uniform and complete, and allowing the cured gel to form a continuous and dense network structure. This not only ensures the unobstructed ion transport channels and reduces the internal resistance of the semi-solid battery, but also enhances the stability of the electrode-electrolyte interface, thereby improving the battery's cycle life, capacity retention, and safety performance.
[0024] Meanwhile, the curing process of this invention, by gradually increasing pressure and temperature, allows the active material particles inside the battery cell to come into closer contact under pressure, and allows the adhesive inside the battery cell to play a full role, reducing internal voids, improving the structural stability of the battery cell, and reducing performance degradation caused by structural changes during charging and discharging.
[0025] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation
[0026] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
[0027] Example 1
[0028] This embodiment provides a method for in-situ curing of semi-solid-state batteries, the method comprising the following steps: S1: Mix the polymerized monomer with the electrolyte to form a gel precursor liquid 1; mix the initiator with the electrolyte to form a gel precursor liquid 2; inject the gel precursor liquid 1 into the battery cell and perform high-temperature impregnation (temperature 45°C, time 36h).
[0029] S2: Inject the gel precursor solution 2 into the battery cell after it has been impregnated in the high temperature stage, and then proceed with the impregnation in the medium temperature stage (temperature 35°C, time 6h) and the low temperature stage (temperature 25°C, time 6h) in sequence.
[0030] S3: The cells that have been impregnated in the low-temperature stage are sequentially cured under low-temperature and low-pressure conditions (temperature 35°C, pressure 200N, time 0.5h, pre-curing), medium-temperature and medium-pressure conditions (temperature 45°C, pressure 500N, time 0.5h, pre-curing), and high-temperature and high-pressure conditions (temperature 75°C, pressure 750N, time 1.5h, formal curing) to obtain a semi-solid-state battery.
[0031] In addition, in this embodiment: Based on the total weight (440g) of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2, the amount of electrolyte used in the gel precursor solution 1 is 85% by weight (374g), and the amount of electrolyte used in the gel precursor solution 2 is 15% by weight (66g). In the gel precursor solution 1: the polymeric monomer accounts for 1% of the mass percentage of the gel precursor solution 1; In the gel precursor solution 2: the initiator accounts for 5% of the mass percentage of the gel precursor solution 2; Based on the total weight of the electrolyte, the electrolyte comprises 15% LiPF6, 80% carbonate solvent (EC ethylene carbonate: EMC methyl ethyl carbonate = 3:7 (mass ratio)) and 5% functional additive (DTD ethylene sulfate: FEC fluoroethylene carbonate = 2:3 (mass ratio)). The polymer monomer is pentaerythritol tetraacrylate; The initiator is azobisisobutyronitrile.
[0032] Comparative Example 1
[0033] This comparative example provides an in-situ curing method for a semi-solid-state battery, the method comprising the following steps: S1: Mix the polymerized monomer with the electrolyte to form a gel precursor solution 1; mix the initiator with the electrolyte to form a gel precursor solution 2; inject the gel precursor solution 1 into the battery cell to perform the first stage of impregnation (temperature 25°C, time 36h).
[0034] S2: Inject the gel precursor solution 2 into the battery cell after the first stage of impregnation for the second stage of impregnation (temperature 25°C, time 12h).
[0035] S3: The cells that have been impregnated in the low-temperature stage are sequentially cured under low-temperature conditions (temperature 35°C, pressure 750N, time 0.5h, pre-curing), medium-temperature conditions (temperature 45°C, pressure 750N, time 0.5h, pre-curing), and high-temperature conditions (temperature 75°C, pressure 750N, time 1.5h, formal curing) to obtain a semi-solid-state battery.
[0036] In addition, in this comparative example: Based on the total weight (440g) of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2, the amount of electrolyte used in the gel precursor solution 1 is 85% by weight (374g), and the amount of electrolyte used in the gel precursor solution 2 is 15% by weight (66g). In the gel precursor solution 1, the mass ratio of polymeric monomer to electrolyte is the same as in Example 1; In the gel precursor solution 2, the mass ratio of initiator to electrolyte is the same as in Example 1.
[0037] The electrolyte is the same as that in Example 1; The polymer monomers are the same as those in Example 1; The initiator is the same as that in Example 1.
[0038] Comparative Example 2
[0039] This comparative example provides an in-situ curing method for a semi-solid-state battery, the method comprising the following steps: S1-S2 are the same as Comparative Example 1.
[0040] S3: The cells that have been impregnated in the low-temperature stage are sequentially cured under low-pressure conditions (temperature 75°C, pressure 200N, time 0.5h, pre-curing), medium-pressure conditions (temperature 75°C, pressure 500N, time 0.5h, pre-curing), and high-pressure conditions (temperature 75°C, pressure 750N, time 1.5h, formal curing) to obtain a semi-solid-state battery.
[0041] In addition, in this comparative example: Based on the total weight (440g) of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2, the amount of electrolyte used in the gel precursor solution 1 is 85% by weight (374g), and the amount of electrolyte used in the gel precursor solution 2 is 15% by weight (66g). In the gel precursor solution 1, the mass ratio of polymeric monomer to electrolyte is the same as in Example 1; In the gel precursor solution 2, the mass ratio of initiator to electrolyte is the same as in Example 1.
[0042] The electrolyte is the same as that in Example 1; The polymer monomers are the same as those in Example 1; The initiator is the same as that in Example 1.
[0043] Comparative Example 3
[0044] This comparative example provides an in-situ curing method for a semi-solid-state battery, the method comprising the following steps: S1-S2 are the same as in Example 1.
[0045] S3: The cells that have been impregnated in the low-temperature stage are sequentially cured under low-pressure conditions (temperature 75°C, pressure 200N, time 0.5h, pre-curing), medium-pressure conditions (temperature 75°C, pressure 500N, time 0.5h, pre-curing), and high-pressure conditions (temperature 75°C, pressure 750N, time 1.5h, formal curing) to obtain a semi-solid-state battery.
[0046] In addition, in this comparative example: Based on the total weight (440g) of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2, the amount of electrolyte used in the gel precursor solution 1 is 85% by weight (374g), and the amount of electrolyte used in the gel precursor solution 2 is 15% by weight (66g). In the gel precursor solution 1, the mass ratio of polymeric monomer to electrolyte is the same as in Example 1; In the gel precursor solution 2, the mass ratio of initiator to electrolyte is the same as in Example 1.
[0047] The electrolyte is the same as that in Example 1; The polymer monomers are the same as those in Example 1; The initiator is the same as that in Example 1.
[0048] Comparative Example 4
[0049] This comparative example provides an in-situ curing method for a semi-solid-state battery, the method comprising the following steps: S1: The polymerizable monomer, initiator, and electrolyte are mixed to form a gel precursor solution 3; the gel precursor solution 3 is injected into the battery cell for impregnation (temperature 25℃, time 48h). In this comparative example, due to the injection of a large amount of electrolyte at one time, electrolyte aggregation may occur inside the battery cell, making it difficult to fully impregnate some areas, affecting ion conduction efficiency. Furthermore, the electrolyte viscosity is high at room temperature, making impregnation difficult.
[0050] S2: The impregnated battery cell is then subjected to a single curing process (temperature 75℃, pressure 750N, time 2h) to obtain a semi-solid battery. In this comparative example, the instantaneous application of high pressure and high temperature may lead to uneven stress distribution within the battery cell, resulting in localized structural damage, which in turn affects the battery's cycle life and safety.
[0051] In addition, in this comparative example: The mass of the electrolyte in the gel precursor solution 3 is 440g; In the gel precursor solution 3, the mass ratio of the polymer monomer, initiator and electrolyte is 1:5:94.
[0052] The electrolyte is the same as that in Example 1; The polymer monomers are the same as those in Example 1; The initiator is the same as that in Example 1.
[0053] Test case
[0054] This test example subjected the semi-solid-state batteries prepared in the above embodiments and comparative examples to high-temperature storage at 55℃ and 100% SOC (fully charged battery) to compare capacity recovery rate, capacity retention rate, and DCIR growth rate (DC internal resistance growth rate). The test results are shown in Table 1 below.
[0055] Table 1
[0056] As can be seen from the comparison in Table 1, the process of Example 1 significantly improves the wetting effect and structural stability of the battery cell, enabling the formation of a denser, more uniform, and stable solid electrolyte interphase (SEI) film on the electrode surface. This high-quality SEI film can effectively reduce the occurrence of side reactions, while providing a good ion conduction channel, thereby improving the battery's capacity, cycle performance, and safety performance. Furthermore, optimizing some of the conditions (Comparative Examples 1-3) also yields improvement results.
[0057] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. A method for in-situ solidification of a semi-solid-state battery, characterized in that, The method includes the following steps: S1: Mix the polymer monomer with the electrolyte to form a gel precursor liquid 1; mix the initiator with the electrolyte to form a gel precursor liquid 2; inject the gel precursor liquid 1 into the battery cell for high-temperature impregnation; S2: Inject the gel precursor liquid 2 into the battery cell after it has been impregnated in the high-temperature stage, and then perform impregnation in the medium-temperature stage and the low-temperature stage in sequence. S3: The cells that have been immersed in the low-temperature stage are sequentially cured under low-temperature and low-pressure conditions, medium-temperature and medium-pressure conditions, and high-temperature and high-pressure conditions to obtain a semi-solid-state battery.
2. The in-situ solidification method for semi-solid-state batteries according to claim 1, wherein, Based on the total weight of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2, the amount of electrolyte used in the gel precursor solution 1 is x% by weight, and the amount of electrolyte used in the gel precursor solution 2 is (100-x)% by weight.
3. The in-situ solidification method for semi-solid-state batteries according to claim 2, wherein, Based on the total weight of the electrolyte in the gel precursor solution 1 and the gel precursor solution 2, the amount of electrolyte in the gel precursor solution 1 is 80-90% by weight, and the amount of electrolyte in the gel precursor solution 2 is 10-20% by weight.
4. The in-situ solidification method for semi-solid-state batteries according to claim 1, wherein, The immersion temperature during the high-temperature stage is ≥45℃, and the immersion time is 30-42h.
5. The in-situ solidification method for semi-solid-state batteries according to claim 1, wherein, The immersion temperature during the intermediate temperature stage is 32-40℃, and the time is 3-9 hours.
6. The in-situ curing method for semi-solid-state batteries according to claim 1, wherein, The immersion temperature during the low-temperature stage is 20-28℃, and the time is 3-9 hours.
7. The in-situ curing method for semi-solid-state batteries according to claim 1, wherein, The curing conditions under low temperature and low pressure are 30-40℃, 150-250N, and 0.3-0.8h.
8. The in-situ solidification method for semi-solid-state batteries according to claim 1, wherein, The curing conditions under medium temperature and medium pressure are 42-50℃, 450-550N, and 0.3-0.8h.
9. The in-situ curing method for semi-solid-state batteries according to claim 1, wherein, The high-temperature and high-pressure curing conditions are characterized by a curing temperature of 70-80℃, a pressure of 700-800N, and a curing time of 1-2 hours.
10. A semi-solid battery prepared by the in-situ solidification method for semi-solid batteries according to any one of claims 1-9.