Viscosity self-adjusting electrolyte and microfluidic distribution system thereof

Abstract

The invention provides a viscosity self-adjusting electrolyte and a microfluidic distribution system thereof, and relates to the technical field of lithium batteries. The electrolyte comprises a basic electrolyte, cyclodextrin and a self-adjusting viscosity additive, the self-regulating viscosity additive comprises a four-arm star block copolymer. According to the invention, a dynamic network is constructed by using the host-guest interaction of the four-arm star-shaped block copolymer and cyclodextrin, so that the dual self-adaptive adjustment of the viscosity of the electrolyte on temperature and potential is realized. The system is spontaneously tackified at high temperature or high pressure through the temperature-sensitive and electrochemical response arm to inhibit side reaction, and meanwhile, efficient ion transmission is maintained by means of the ion conduction arm, so that the safety is remarkably improved on the premise of not sacrificing the conductivity, and the technical contradiction between inhibition of thermal runaway and guarantee of fast charge kinetics is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and more specifically, to a self-adjusting viscosity electrolyte and its microfluidic distribution system. Background Technology

[0002] With the widespread adoption of new energy vehicles and portable electronic devices, lithium-ion batteries, as core energy storage devices, have seen their energy density and charging speed become key indicators for evaluating product performance. Especially in the electric vehicle sector, achieving fast charging (e.g., at 3C rates or higher) has become an urgent industry requirement to alleviate range anxiety. The performance of lithium-ion batteries, particularly their fast-charging capability and safety, largely depends on the properties of the electrolyte. As the carrier of ion transport within the battery, the electrolyte's mass transfer kinetics directly affect the reaction rate at the electrode interface and the overall polarization level of the battery.

[0003] Currently, to meet the usage requirements of lithium-ion batteries under different environments and operating conditions, existing technologies typically employ methods to optimize electrolyte formulations. Common methods include adding functional additives to the base solvent or adjusting the solvent ratio. For example, to improve low-temperature performance, a low-viscosity co-solvent (such as a linear carboxylic acid ester) is often added to reduce system viscosity and increase ionic conductivity; while to improve safety and stability at high temperatures, thickeners or film-forming additives are added to suppress side reactions and gas generation. In addition, some battery systems employ external thermal management systems or simple additive replenishment systems, attempting to regulate the battery's operating environment based on voltage or temperature thresholds.

[0004] However, existing electrolyte systems present inherent contradictions when dealing with high-rate fast charging and wide-temperature operating conditions. On the one hand, during fast charging, the migration rate of lithium ions in the electrolyte often lags behind the electrode reaction rate, leading to significant concentration polarization and easily causing lithium plating and capacity decay. On the other hand, the viscosity requirements of the electrolyte are drastically different at different temperatures and voltages: low temperatures require low viscosity to maintain ion conduction, but low-viscosity components are often highly volatile and have poor high-temperature stability, easily leading to safety risks; high temperatures or high voltages require high viscosity to suppress side reactions, but traditional thickeners cause a sharp drop in ion mobility at low temperatures, resulting in a performance slump. In addition, existing electrolyte formulations are mostly fixed "static" formulations before leaving the factory, which cannot cope with the complex dynamic changes inside the battery.

[0005] In summary, existing electrolyte technologies primarily rely on offline parameter optimization or simple open-loop feedforward control, lacking real-time response capabilities to changes in the battery's internal microstate. Electrolytes with fixed viscosity cannot simultaneously ensure low-temperature conductivity and stability at high temperatures / high voltages, nor can they accommodate localized performance differences caused by uneven temperature distribution within the battery (such as temperature differences between the center and edges). This single, static electrolyte system fails to meet the comprehensive requirements of modern lithium-ion batteries for safety, fast-charging performance, and cycle life under all operating conditions, becoming a bottleneck limiting further breakthroughs in battery performance.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a self-adjusting viscosity electrolyte and its microfluidic distribution system. The self-adjusting viscosity electrolyte utilizes the host-guest interaction between a four-arm star-shaped block copolymer and cyclodextrin to achieve dual adaptive adjustment of electrolyte viscosity to temperature and potential while ensuring efficient ion conduction. This solves the technical problem of balancing battery high-temperature and high-pressure stability with fast-charging dynamic performance.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a self-adjusting viscosity electrolyte, the electrolyte comprising a base electrolyte, cyclodextrin, and a self-adjusting viscosity additive; The self-adjusting viscosity additive comprises a four-armed star-shaped block copolymer; The four-armed star-shaped block copolymer has three functional arms: a temperature-sensitive arm, an electrochemically responsive arm, and an ion-conducting arm. Wherein, the temperature-sensitive arm is a polymer chain segment with a low critical dissolution temperature; The electrochemical response arm contains a ferrocene group; The ion-conducting arm is a polyether-based chain segment.

[0009] In an optional embodiment, the temperature-sensitive arm is a poly(N-isopropylacrylamide) segment; and / or, The ion-conducting arm is a polyoxyethylene segment; and / or... The electrochemical response arm is a polyoxyethylene segment containing ferrocene side groups; and / or, The lower critical dissolution temperature of the temperature-sensitive arm is 30℃~35℃; and / or, The electrochemical response arm is in an oxidized state and undergoes hydrophobic aggregation at a potential above 4V; and / or, Based on the total weight of the electrolyte, the mass percentage of the self-adjusting viscosity additive is 5wt%~15wt%.

[0010] In an optional embodiment, the base electrolyte comprises a lithium salt and an organic solvent; Preferably, the lithium salt comprises lithium hexafluorophosphate; Preferably, the organic solvent includes ethylene carbonate and ethyl methyl carbonate; Preferably, the volume ratio of ethylene carbonate to methyl ethyl carbonate is 2:8 to 4:6.

[0011] In an optional embodiment, the viscosity of the electrolyte is 5 cP to 10 cP at 25°C; the viscosity is 40 cP to 60 cP at 45°C; and the viscosity of the electrolyte increases by at least 100% when the potential is higher than 4V.

[0012] In a second aspect, the present invention provides an electrolyte microfluidic distribution system, the system being configured to inject a self-adjusting viscosity electrolyte as described in any of the foregoing embodiments into the battery. The electrolyte microfluidic distribution system includes: A distributed sensor array is used to monitor local temperature and impedance inside the battery; The microfluidic actuator includes a reservoir for storing a base electrolyte and a self-adjusting viscosity additive concentrate, a micro mixer, and a piezoelectric microvalve. The control unit is used to calculate the required electrolyte viscosity for the target area based on the local temperature and impedance, and to control the opening degree of the micromixer and the piezoelectric microvalve.

[0013] In an optional implementation, the control unit pre-stores an AI decision model; the AI ​​decision model is constructed by establishing a four-dimensional mapping relationship between electrolyte viscosity, temperature, current, and ionic conductivity, and setting a concentration polarization voltage threshold; the control unit is configured to: when the calculated concentration polarization voltage exceeds the threshold, output a control command to increase the proportion of self-adjusting viscosity additive; and / or, The micromixer is a Y-type micromixer; and / or, The microfluidic actuator delivers electrolyte through microchannels embedded inside the battery, the width of which is 100μm~300μm; and / or, The response time of the piezoelectric microvalve is less than 20ms; and / or, The impedance sensor in the distributed sensor array is a three-electrode impedance sensor containing a lithium reference electrode, used to monitor the concentration polarization impedance at the electrode interface.

[0014] Thirdly, the present invention provides a method for adaptive viscosity control of a fast-charging battery based on the electrolyte microfluidic distribution system described in any of the foregoing embodiments, comprising: Collect local temperature and impedance data inside the battery; The local temperature data and impedance data are input into a preset decision model; the decision model is based on the coupling relationship of viscosity-temperature-current-conductivity, with the goal of minimizing concentration polarization, and calculates the optimal viscosity value required for the target region. Based on the optimal viscosity value, calculate the mixing ratio of the base electrolyte and the self-adjusting viscosity additive concentrate; Adjust the opening of the piezoelectric microvalve in the microfluidic actuator, mix according to the mixing ratio, and then inject into the target area of ​​the battery; Preferably, when the temperature of the central region of the battery module is higher than that of the edge region, and the temperature difference exceeds a preset threshold, the control unit controls the proportion of self-adjusting viscosity additive in the electrolyte injected into the central region to be higher than the proportion injected into the edge region.

[0015] Fourthly, the present invention provides a lithium-ion battery, wherein the lithium-ion battery is filled with a self-adjusting viscosity electrolyte as described in any of the foregoing embodiments, or the lithium-ion battery integrates an electrolyte microfluidic distribution system as described in any of the foregoing embodiments.

[0016] Fifthly, the present invention provides an electrical device including a lithium-ion battery as described in the foregoing embodiments.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The electrolyte provided by this invention constructs an intelligent response system capable of responding to changes in the internal microenvironment of the battery by introducing a self-regulating viscosity additive containing a four-armed star-shaped block copolymer and cyclodextrin. This system utilizes the host-guest interaction between cyclodextrin and the ferrocene groups on the electrochemical response arms of the copolymer to form a dynamically reversible physical cross-linking network within the electrolyte. This molecular-scale structural design transforms the electrolyte from a static ion transport medium into a dynamic system capable of adjusting its rheological properties in real time according to external stimuli, thereby achieving flexible control of the electrolyte viscosity.

[0018] Specifically, this electrolyte solves the problem of conflicting viscosity requirements of traditional electrolytes under different operating conditions through the synergistic effect of its temperature-sensitive arm and electrochemical response arm. When the battery is in a high-temperature environment, the temperature-sensitive arm undergoes a phase transition and shrinks or aggregates due to its low critical dissolution temperature, causing the electrolyte viscosity to automatically increase. Simultaneously, under high voltage or high current conditions, the ferrocene groups in the electrochemical response arm oxidize and induce hydrophobic aggregation, further enhancing the viscosity. This dual-response mechanism effectively suppresses electrolyte decomposition and side reactions at the electrode interface at high temperatures or high potentials, significantly improving the thermal stability and safety of the battery, while maintaining a low viscosity at low temperatures or ambient temperature and pressure, ensuring excellent wettability and low-temperature performance.

[0019] Furthermore, the polyether-based ion-conducting arms specifically integrated into this four-armed star-shaped block copolymer provide an independent, rapid channel for lithium-ion transport. Unlike traditional methods that simply increase polymer molecular weight to thicken the electrolyte, which leads to a significant decrease in ionic conductivity, this structure ensures that the electrolyte maintains a high ion mobility while increasing viscosity to suppress side reactions. This structural decoupling of viscosity regulation and ion conduction effectively reduces concentration polarization during high-rate charge and discharge processes, improving battery safety while ensuring its kinetic performance and fast-charging capability. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the functional modules of the electrolyte microfluidic distribution system provided in the embodiments of this application; Figure 2 This is a flowchart illustrating the adaptive viscosity control method for fast-charging batteries provided in the embodiments of this application. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0023] This application provides a self-adjusting viscosity electrolyte, comprising a base electrolyte, cyclodextrin, and a self-adjusting viscosity additive; the self-adjusting viscosity additive comprises a four-armed star-shaped block copolymer; the four-armed star-shaped block copolymer has three functional arms, namely a temperature-sensitive arm, an electrochemically responsive arm, and an ion-conducting arm; wherein, the temperature-sensitive arm is a polymer segment with a low critical dissolution temperature; the electrochemically responsive arm contains ferrocene groups; and the ion-conducting arm is a polyether segment.

[0024] The aforementioned self-regulating viscosity electrolyte can refer to a battery electrolyte solution that can sense changes in the external environment (such as temperature and potential) and automatically change its own rheological properties (mainly viscosity).

[0025] The basic electrolyte can refer to the part that constitutes the main body of the electrolyte, which can undertake the basic function of providing an ion transport medium, and can contain a mixed system of lithium salt and organic solvent.

[0026] The cyclodextrins mentioned above are cyclic oligosaccharide molecules. In this embodiment, they can exist as an independent component, acting as the "host" molecule in supramolecular chemistry, possessing hydrophobic cavities, and capable of recognizing and encapsulating specific "guest" molecules.

[0027] The aforementioned self-adjusting viscosity additive is the core component for achieving viscosity adjustment, and it contains specific polymer compounds. Among them, the additive includes a four-armed star-shaped block copolymer. The "four-armed star" provides the topological structure of the polymer, which has a central core from which four polymer chains (arms) radiate outward, rather than a traditional linear structure.

[0028] The term "block copolymer" refers to a molecule in which each arm or the entire molecule is composed of polymer segments with different chemical properties connected by covalent bonds.

[0029] The aforementioned functional arms refer to the four arms mentioned above, which are classified into three categories based on their chemical properties and functions: (1) Temperature-sensitive arms (polymer segments with low critical solution temperature): These polymer segments are sensitive to temperature. "Low critical solution temperature (LCST)" refers to a specific transition temperature. Below this temperature, the polymer has good solubility (chain extension), while above this temperature, the polymer undergoes a phase transition and its solubility decreases (chain contraction or aggregation).

[0030] (2) Electrochemical response arm (containing ferrocene group): This type of segment is sensitive to potential (voltage). Ferrocene is an organometallic compound with good redox reversibility. Here, it is used as a functional group to modify the polymer chain.

[0031] (3) Ion conduction arm (polyether segment): Polyether (such as polyethylene oxide) is a well-known solid polymer electrolyte substrate. It has polar oxygen atoms, which can complex and transport lithium ions to maintain the ion conduction capability of the electrolyte.

[0032] The electrolyte provided in this embodiment is based on the principles of "multiple stimulus response" and "host-guest supramolecular interaction": First, the supramolecular cross-linking principle, based on the simultaneous presence of "cyclodextrin" and copolymers containing "ferrocene groups". Ferrocene groups are typical hydrophobic guest molecules, capable of entering the hydrophobic cavities of cyclodextrin to form stable inclusion complexes (host-guest interaction). This non-covalent interaction allows dispersed star-shaped copolymer molecules to form a physical cross-linking network, thereby affecting the macroscopic viscosity. Second, the temperature response principle, that is, when the internal temperature of the battery rises above the LCST of the temperature-sensitive arm, the temperature-sensitive arm undergoes a phase transition from hydrophilic to hydrophobic, leading to molecular chain contraction or hydrophobic association. This conformational change alters the hydrodynamic volume or aggregation state of the polymer in the electrolyte, thereby regulating the viscosity. Finally, the potential response principle, that is, when the battery is at a high potential, the ferrocene groups on the electrochemical response arm undergo an oxidation reaction (from a reduced state to an oxidized state). The properties of oxidized ferrocene change (such as changes in polarity or interaction with other groups), which in turn affects its host-guest binding state with cyclodextrin or its intermolecular aggregation state, thus achieving responsive viscosity regulation in response to changes in potential.

[0033] Based on the above structure, this electrolyte differs from traditional fixed-viscosity electrolytes. This product can adaptively adjust for both "temperature" and "potential" dimensions simultaneously. At high temperatures or high voltages, viscosity can be increased through conformational changes or enhanced cross-linking of molecular chains, thereby suppressing electrolyte decomposition and side reactions, and improving safety. At low temperatures or low voltages, it maintains a lower viscosity, which is beneficial for wetting. It ensures ion transport performance: due to the specially designed "ion-conducting arms (polyether segments)" in the molecular structure, these specific segments still provide transport channels for lithium ions even when viscosity increases (e.g., forming a network structure). This means that viscosity adjustment does not sacrifice the battery's conductivity, solving the problem of balancing "high viscosity" and "high conductivity." The adjustment mechanism based on host-guest interactions (cyclodextrin-ferrocene) and phase transitions (LCST) is generally physically reversible, allowing the electrolyte to adapt to repeated environmental changes during battery charge-discharge cycles.

[0034] The temperature-sensitive arm described above can be a poly(N-isopropylacrylamide) (PNIPAM) segment or a polyvinylcaprolactam (PVCL) segment, as long as it possesses LCST properties. Examples of the ion-conducting arms described above can be segments of polyethylene oxide (PEO), polypropylene oxide (PPO), or copolymers thereof. For example, it can be a central core connected to four arms, where some arms are mainly composed of PEO (conducting), some arms have ferrocene terminals (electro-responsive), and some arms contain PNIPAM segments (temperature-sensitive).

[0035] In the four arms of the aforementioned four-armed star-shaped block copolymer, the proportions of the three functions can be adjusted. For example, it can be two ion-conducting arms, one temperature-sensitive arm, and one electrochemically responsive arm; or each arm can contain blocks with different functions (such as block copolymers).

[0036] Regarding group modification, ferrocene groups can be located at the end of the chain segment or distributed as side groups in the middle of the chain segment.

[0037] Cyclodextrins, which can be of the types α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin, can be used, depending on their size matching with the ferrocene group.

[0038] In some embodiments, the temperature-sensitive arm is a poly(N-isopropylacrylamide) segment.

[0039] The aforementioned poly(N-isopropylacrylamide) (PNIPAM) segment represents a specific chemical selection for the "temperature-sensitive arm." PNIPAM is a typical temperature-sensitive polymer, where the hydrophilic groups (amide groups) and hydrophobic groups (isopropyl groups) on its molecular chain compete in the aqueous phase or specific solvents. This limitation clearly defines the use of PNIPAM's phase transition properties to achieve a temperature response.

[0040] In some embodiments, the ion-conducting arm is a polyoxyethylene segment.

[0041] The aforementioned polyethylene oxide (PEO) segments represent a specific chemical selection for the "ion-conducting arm." PEO possesses flexible segments and ether oxygen atoms capable of dissociating from lithium salts, making it a commonly used ion transport medium in polymer electrolytes.

[0042] In some embodiments, the electrochemical response arm is a polyoxyethylene segment containing ferrocene side groups.

[0043] The aforementioned polyoxyethylene segment containing ferrocene side groups is a specific embodiment of the "electrochemical response arm." This indicates that the ferrocene groups are modified onto the PEO backbone as side groups. This structural design retains the flexibility of the PEO chain while introducing the electrochemical activity of ferrocene.

[0044] In some embodiments, the lower critical melting temperature of the temperature-sensitive arm is 30°C to 35°C. For example, it can be 30°C, 31°C, 31.5°C, 32°C, 32.5°C, 33°C, 33.5°C, 34°C, 34.5°C, 35°C, etc.

[0045] The lower critical solution temperature (LCST) refers to the specific temperature threshold at which a thermosensitive polymer undergoes a phase transition. Below this temperature, the polymer dissolves / expands; above this temperature, the polymer shrinks / aggregates.

[0046] Limiting the LCST to 30℃~35℃ is to match the normal operating temperature range of lithium batteries with the temperature range requiring thermal protection. When the battery temperature rises slightly above the normal range (e.g., above 32℃), the electrolyte begins to thicken, which can sensitively suppress early signs of thermal runaway.

[0047] In some embodiments, the electrochemical response arm is in an oxidized state and undergoes hydrophobic aggregation at a potential above 4V.

[0048] The oxidation state and hydrophobic aggregation characterize the microscopic physicochemical behavior of the electrochemical response arm. At a specific potential (>4V), the ferrocene group loses electrons and becomes oxidized (positively charged). This change in state leads to a change in its solubility parameter, which in turn triggers changes in the hydrophobic interactions between molecular chains or the binding force with other components (such as cyclodextrin), macroscopically manifested as aggregation and thickening.

[0049] The response occurs at a potential above 4V to address high-voltage fast charging or overcharging scenarios. At this potential, the viscosity is significantly increased through the oxidation and aggregation of ferrocene, which can protect the positive electrode interface and reduce electrolyte oxidation and decomposition at high potentials.

[0050] In some embodiments, the self-adjusting viscosity additive has a mass percentage content of 5wt% to 15wt% based on the total weight of the electrolyte. For example, it can be 5wt%, 6wt%, 7.5wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12.5wt%, 14wt%, 15wt%, etc.

[0051] The addition limit of 5wt% to 15wt% strikes a balance between "viscosity adjustment effect" and "battery energy density / cost". Too low a content may result in insufficient adjustment capability, while too high a content may affect the overall ionic conductivity or increase cost.

[0052] In some embodiments, the base electrolyte comprises a lithium salt and an organic solvent; Preferably, the lithium salt comprises lithium hexafluorophosphate.

[0053] Lithium hexafluorophosphate (LiPF6) is a commonly used lithium salt in lithium-ion batteries, providing a source of lithium ions in the electrolyte and exhibiting good ionic conductivity and aluminum foil passivation capability.

[0054] Preferably, the organic solvent includes ethylene carbonate and ethyl methyl carbonate.

[0055] The aforementioned ethylene carbonate (EC) is an organic solvent with a high dielectric constant, which can effectively dissociate lithium salts and participate in the formation of an SEI film (solid electrolyte interface film) on the negative electrode surface.

[0056] The aforementioned ethyl methyl carbonate (EMC) is a low-viscosity linear carbonate solvent used to reduce the overall viscosity of the electrolyte and improve the migration rate of lithium ions.

[0057] A basic electrolyte system was constructed by combining EC (high dielectric, good film formation but high viscosity) and EMC (low viscosity, good wetting). This system provides a good dispersion medium for self-adjusting viscosity additives and ensures the basic performance of the battery when the viscosity-enhancing mechanism is not triggered.

[0058] Preferably, the volume ratio of ethylene carbonate to methyl ethyl carbonate is 2:8 to 4:6. For example, this ratio can be 2:8, 2.5:7.5, 3:7, 3.2:6.8, 3.5:6.5, 3.8:6.2, 4:6, etc.

[0059] The specific volume ratio range is designed to optimize the overall performance of the base electrolyte (such as conductivity, low-temperature performance, and film quality) and ensure good compatibility with self-regulating additives.

[0060] In some embodiments, the viscosity of the electrolyte at 25°C is 5 cP to 10 cP (e.g., 5 cP, 5.5 cP, 6 cP, 7 cP, 7.5 cP, 8 cP, 8.5 cP, 9 cP, 9.5 cP, 10 cP, etc.); the viscosity at 45°C is 40 cP to 60 cP (e.g., 40 cP, 42 cP, 45 cP, 48 cP, 50 cP, 52 cP, 55 cP, 57 cP, 58 cP, 60 cP, etc.); and the viscosity of the electrolyte increases by at least 100% when the potential is higher than 4V.

[0061] The viscosity (5 cP~10 cP) at 25°C defines the rheological state of the electrolyte at room temperature (normal operating temperature). The viscosity (40 cP~60 cP) at 45°C defines the rheological state of the electrolyte at high temperature (abnormal or heat accumulation temperature).

[0062] The viscosity increase of at least 100% when the potential is above 4V limits the range of the electrolyte's response to voltage stimulation.

[0063] Maintaining a low viscosity of 5cP~10cP at 25℃ ensures rapid migration of lithium ions at room temperature, which is beneficial for achieving room-temperature rate performance (such as fast charging capability) and good wettability. At 45℃, the viscosity jumps to 40cP~60cP (several times higher than at room temperature). This significant difference in viscosity utilizes high viscosity to hinder excessive ion movement, thereby physically suppressing side reaction rates and gas production at high temperatures, achieving a "high-temperature automatic safety mode." The voltage-triggered viscosity multiplication effect provides an additional safety barrier for the battery during high-voltage charging, preventing uncontrolled oxidation and decomposition reactions on the positive electrode side.

[0064] refer to Figure 1 This application also provides an electrolyte microfluidic distribution system, which is configured to inject a self-adjusting viscosity electrolyte as described in any of the foregoing embodiments into the battery. The electrolyte microfluidic distribution system includes: A distributed sensor array 10 is used to monitor local temperature and impedance inside the battery; The microfluidic actuator 20 includes a reservoir for storing a base electrolyte and a self-adjusting viscosity additive concentrate, a micro mixer, and a piezoelectric microvalve. The control unit 30 is used to calculate the required electrolyte viscosity for the target area based on the local temperature and impedance, and to control the opening degree of the micro-mixer and the piezoelectric micro-valve.

[0065] The aforementioned electrolyte microfluidic distribution system refers to a fluid management hardware architecture integrating microelectromechanical systems (MEMS) technology, specifically designed for the precise and dynamic delivery and control of electrolytes within batteries. It changes the traditional battery electrolyte "one-time filling, lifetime fixation" model.

[0066] In the distributed sensor array, "distributed" means that the sensors are not a single point, but are arranged in an array at different locations inside the battery (such as the center, edge, near the tabs, etc.), which has spatial resolution capability and can capture the non-uniform distribution of the physical field inside the battery.

[0067] The phrase "monitoring local temperature and impedance" refers to the sensor's ability to simultaneously collect thermal parameters (temperature) and electrochemical parameters (impedance, reflecting concentration polarization or interface state) of a specific micro-region, serving as the data basis for system decision-making.

[0068] In the microfluidic actuator, the reservoirs (storing liquids separately) constitute at least two independent liquid sources within the system. One can be a "base electrolyte" (typically with low viscosity to ensure conductivity), and the other can be a "self-adjusting viscosity additive concentrate" (containing a high concentration of four-armed star-shaped block copolymers as a viscosity-adjusting mother liquor). This dual-reservoir design is a prerequisite for on-demand mixing. The micromixer, a microfluidic device located between the reservoirs and the battery injection point, is used to rapidly and uniformly mix the two liquids at a microscale, instantly synthesizing an electrolyte with a specific additive concentration. The piezoelectric microvalve is a micro-valve that uses the inverse piezoelectric effect of piezoelectric materials (such as PZT) to control fluid flow or on / off states. It can have extremely fast response times (milliseconds) and high control precision.

[0069] The control unit acts as the "brain" of the system, receiving signals from sensors, processing them through algorithms, and then sending instructions to the actuators. Its core function is to establish a logical mapping between "sensory data" and "execution actions."

[0070] This system is based on the principles of "closed-loop feedback" and "in-situ dynamic synthesis": First, a distributed sensor array scans the state of various points inside the battery in real time, identifying "hot spots" (high-temperature areas) or "polarization points" (impedance anomaly areas). The control unit then determines the current viscosity requirements of the electrolyte for each region based on the collected data. For example, high viscosity is needed in high-temperature areas to suppress side reactions, while low viscosity is needed in low-temperature or high-current areas to reduce polarization. Upon entering the execution phase, the control unit calculates the mixing ratio of the "base solution" and the "concentrate" required to achieve the target viscosity. Subsequently, by precisely adjusting the opening (or frequency) of the piezoelectric micro-valve, the two liquid streams are controlled to enter the micro-mixer. The mixed electrolyte is then precisely injected into the target area of ​​the battery. Because the concentrate contains the aforementioned four-armed star-shaped block copolymer, the viscosity of the injected liquid changes with the mixing ratio, thereby achieving the correction of the local microenvironment.

[0071] This system offers unparalleled active management capabilities compared to traditional batteries, resolving the issue of uneven temperature distribution (hot center, cold edge) within large-size batteries or modules. The system can adapt to local conditions, injecting high-viscosity components into the hot central area to suppress gas production and low-viscosity components into the cold edge area to maintain activity, eliminating localized bottlenecks. The system can adjust itself throughout the battery's entire lifecycle and real-time operating conditions. For example, it can synthesize the most suitable electrolyte formula in real time for different stages, such as during fast charging (high rate, prone to polarization) and static high-temperature storage (prone to self-discharge, prone to gas production). Employing piezoelectric microvalve technology combined with microfluidic technology, the system has millisecond-level response capabilities to sudden thermal runaway risks or abrupt changes in operating conditions, significantly improving the battery's active safety.

[0072] In addition to thermocouples and impedance monitoring, distributed sensors can also be extended to fiber optic sensors (simultaneously measuring temperature and stress) or micro-reference electrode arrays.

[0073] Furthermore, the injection channels of the microfluidic actuator can be integrated on the diaphragm, inside the electrode, or through a microchannel network on the current collector.

[0074] In terms of control logic, the computational logic of the control unit can be based on simple threshold judgment, or it can be extended to a high-level algorithm based on model predictive control (MPC).

[0075] In some implementations, the control unit has a pre-stored AI decision model; the AI ​​decision model is constructed by establishing a four-dimensional mapping relationship between electrolyte viscosity, temperature, current and ionic conductivity, and setting a concentration polarization voltage threshold; the control unit is configured to output a control command to increase the proportion of self-adjusting viscosity additive when the calculated concentration polarization voltage exceeds the threshold.

[0076] The aforementioned AI decision-making model refers to a pre-trained or algorithm-based software module stored in the control unit. It is not a simple linear feedback mechanism, but an intelligent algorithm capable of handling multivariate coupling relationships.

[0077] The aforementioned four-dimensional mapping diagram refers to the core database or functional relationships within the model, linking the four key physical quantities of "electrolyte viscosity," "temperature," "operating current," and "ionic conductivity." It reflects which electrolyte viscosity provides the optimal ionic conductivity at different temperatures and currents.

[0078] The concentration polarization voltage threshold mentioned above refers to a set voltage limit value. The concentration polarization voltage reflects the degree of difference between the lithium ion concentration at the electrode surface and the concentration in the bulk solution. Exceeding this threshold means that the ion supply is severely lagging, facing the risk of lithium plating or a sharp drop in performance.

[0079] It should be noted that battery operation is a complex dynamic process. For example, increased current requires low viscosity for rapid mass transfer, while increased temperature requires high viscosity for safety. This model decouples these contradictions through a four-dimensional graph to find the globally optimal solution. This embodiment provides a constraint that "when the concentration polarization voltage exceeds a threshold, the output increases the proportion of self-adjusting viscosity additives." This is based on a specific protection strategy—when excessive polarization may lead to runaway, by increasing the additive (i.e., increasing the concentration of functional polymers), the local transport characteristics are optimized using their ion conduction arms, or the local overheating / side reactions are suppressed using their viscosity-enhancing properties, thereby preventing battery damage.

[0080] In addition to the four dimensions mentioned above, the AI ​​model can also incorporate "battery cycle count (SOH)" or "state of charge (SOC)" as the fifth and sixth dimensions, so that the viscosity adjustment strategy can be dynamically adjusted according to the degree of battery aging.

[0081] In some embodiments, the micromixer is a Y-type micromixer.

[0082] The aforementioned Y-type micromixer can refer to a mixing device with a specific geometric structure in a microfluidic pipeline, in which two fluids (base fluid and additive concentrate) converge in a "Y" shape.

[0083] At the micrometer scale, fluids primarily flow in a laminar manner. The Y-shaped structure utilizes the principle of shortening the diffusion distance and increasing the contact area to enable two fluids to mix rapidly through molecular diffusion without mechanical stirring.

[0084] The Y-type micro-mixer has a simple structure and no dead volume, making it suitable for "instant mixing and use" in the narrow space inside the battery. This ensures that the electrolyte composition injected into the battery is uniform and avoids poor battery performance consistency caused by local concentration gradients.

[0085] Although it is limited to a Y-shape, it can be a planar Y-shape or a three-dimensional Y-shape. It is even possible to add a micro-baffle structure (chaotic mixing) at the Y-shape junction to further improve the mixing efficiency.

[0086] In some embodiments, the microfluidic actuator delivers electrolyte through microchannels embedded inside the battery, the width of which is 100 μm to 300 μm. For example, it can be 100 μm, 150 μm, 200 μm, 250 μm, or 300 μm, etc.

[0087] Embedded microchannels refer to tiny liquid channels directly integrated into internal battery components (such as separators, current collectors, or electrode gaps). A width of 100μm to 300μm defines the channel size. This size is slightly larger than the common separator thickness in lithium-ion batteries, but much smaller than the overall battery size. This size range ensures sufficient liquid flux for electrolyte filling regulation without significantly compromising the battery's volumetric energy density or electrode structure. Utilizing capillary action and microfluidic pressure, electrolyte can be precisely delivered deep into the battery (such as the winding center), solving the problem of traditional electrolyte filling methods failing to wet the central area.

[0088] In some implementations, the response time of the piezoelectric microvalve is less than 20 ms.

[0089] The aforementioned piezoelectric microvalves (with a response time of less than 20 ms) are miniature valves that control the flow of fluid by utilizing the deformation of piezoelectric materials (such as PZT ceramics) under the influence of an electric field. The response time of less than 20 ms limits the system's operating speed.

[0090] In fast charging, current changes often occur on the order of seconds or even milliseconds (such as pulse charging). Traditional mechanical pumps / valve responses are too slow to keep up with the pace of electrochemical reactions. A response speed of <20ms ensures that when the AI ​​model detects anomalies (such as sudden increases in polarization), the system can change the electrolyte formulation almost "in real time," achieving synchronous regulation.

[0091] In some embodiments, the impedance sensor in the distributed sensor array is a three-electrode impedance sensor containing a lithium reference electrode, used to monitor the concentration polarization impedance at the electrode interface.

[0092] Unlike traditional two-electrode (positive-negative) measurement systems, this sensor introduces a third electrode—a lithium reference electrode—to monitor the concentration polarization impedance at the electrode interface.

[0093] In traditional two-electrode systems, only the full cell voltage can be measured, making it impossible to distinguish whether the problem lies with the positive or negative electrode, or to differentiate between ohmic drop and polarization voltage. Introducing a lithium reference electrode provides a stable potential benchmark, allowing the system to precisely separate the polarization information at the working electrode interface. This forms the hardware foundation for the AI ​​model to accurately calculate the concentration polarization voltage, ensuring that control commands are based on precise electrochemical diagnostics, not vague guesses.

[0094] The lithium reference electrode can be a lithium-plated copper wire or an LFP (lithium iron phosphate) reference electrode, as long as it can provide a stable potential reference.

[0095] refer to Figure 2 This application also provides a method for adaptive viscosity control of fast-charging batteries based on the electrolyte microfluidic distribution system described in any of the foregoing embodiments, comprising: Step S1: Collect local temperature data and impedance data inside the battery.

[0096] In this step, the distributed sensor array described in the previous embodiment is used to acquire physical parameters at different spatial locations inside the battery in real time (rather than just the battery surface or the overall average).

[0097] Specifically, the sensor can convert analog signals into digital signals and transmit them to the control unit. For example, the temperature at thermocouple sampling point A is 45℃, and at point B it is 30℃; the three-electrode impedance sensor collects the interface impedance value at point A.

[0098] It enables "high-resolution" perception of the battery's internal microenvironment, allowing the detection of local hotspots or local polarization anomalies that cannot be detected by a single external sensor, thus providing the data foundation for precise control.

[0099] Step S2: Input the local temperature data and impedance data into a preset decision model; the decision model is based on the coupling relationship of viscosity-temperature-current-conductivity, with the goal of minimizing concentration polarization, and calculates the optimal viscosity value required for the target region.

[0100] This step outlines the decision-making process for the method. The logic of the decision model includes: inputs of real-time temperature (T), real-time current (I, which can be provided by the BMS or calculated through impedance), and impedance data (reflecting conductivity and polarization). The coupling relationship is that the model internally describes the complex relationship between viscosity and the above variables through mathematical functions or lookup tables. For example, higher temperatures tend to require higher viscosity (safety), but higher currents tend to require lower viscosity (kinetics).

[0101] The optimization objective is to minimize concentration polarization, which is the core strategy of the algorithm. Excessive concentration polarization is the main cause of lithium plating during fast charging. The algorithm will find a balance between "increasing viscosity to ensure safety" and "reducing viscosity to accelerate transport" to minimize the concentration polarization voltage under this operating condition (or keep it within a safe threshold such as 20mV).

[0102] The output is a physical quantity value, namely the ideal electrolyte viscosity value required for the current region.

[0103] Specifically, multidimensional lookup tables or regression models trained on historical data can be used.

[0104] Step S3: Calculate the mixing ratio of the base electrolyte and the self-adjusting viscosity additive concentrate based on the optimal viscosity value.

[0105] In this step, the abstract "viscosity target" is transformed into a specific "recipe".

[0106] Specifically, the viscosity of the base electrolyte (lower) and the viscosity of the self-adjusting viscosity additive concentrate (higher) are known. The control unit uses a mixture viscosity calculation formula (such as based on logarithmic mixing rules) to deduce the volume ratio or mass ratio of the two required to achieve the target viscosity, thus obtaining a mixing instruction, such as: "Base electrolyte: Additive solution = 70%: 30%".

[0107] In addition, the effect of the current temperature on the basic viscosity of the liquid itself can be considered during the calculation, and temperature compensation calculation can be performed.

[0108] Step S4: Adjust the opening of the piezoelectric microvalve in the microfluidic actuator, mix according to the mixing ratio, and inject into the target area of ​​the battery.

[0109] This step is the "execution" action of the method, which translates digital instructions into physical fluid operations.

[0110] Specifically, the control unit sends drive signals (such as voltage pulses or PWM signals) to the two piezoelectric microvalves controlling the base fluid and additive fluid, respectively. Adjusting the opening refers to changing the size or duration of the valve opening. For example, to achieve a 30% additive concentration, the opening frequency or duty cycle of the additive valve is controlled so that its flow rate accounts for 30% of the total flow rate. After the two fluids are mixed in the micro-mixer, they are directly delivered to the target area inside the battery.

[0111] This step utilizes the millisecond-level response of piezoelectric microvalves to achieve real-time online synthesis of electrolyte formulations without downtime or interference with normal battery operation.

[0112] In some implementations, when the temperature of the central region of the battery module is detected to be higher than that of the edge region, and the temperature difference exceeds a preset threshold, the control unit controls the proportion of self-adjusting viscosity additive in the electrolyte injected into the central region to be higher than the proportion injected into the edge region.

[0113] Among the above limitations, the criterion for triggering this specific control logic is that the center temperature is higher than the edge temperature and the temperature difference exceeds the threshold. Battery modules typically have different heat dissipation conditions, with poor heat dissipation (hotter) at the center and good heat dissipation (colder) at the edges.

[0114] Among the above limitations, controlling the injection ratio in the central region to be greater than the injection ratio in the edge region is a non-uniform injection strategy.

[0115] Specifically, for the central region (hot zone), the control unit calculates a higher additive ratio (e.g., 60%). For the edge region (cold zone), the control unit calculates a lower additive ratio (e.g., 20%). The system delivers electrolytes with different formulations to these two regions via a microfluidic network.

[0116] In the central region, a high proportion of additives results in high viscosity, which is used to suppress side reactions and gas production at high temperatures, preventing thermal runaway and acting as a "thermal barrier." In the edge region, a low proportion of additives maintains low viscosity, ensuring ionic conductivity at low temperatures and preventing "cold-zone lithium deposition" caused by excessive viscosity.

[0117] This step actively balances the electrochemical activity within the module. It not only solves the thermal management problem but also prevents the "weakest link" effect (i.e., preventing the weakest cell or region from dragging down overall performance), thus extending the overall cycle life of the module.

[0118] Furthermore, this strategy can be extended to a "dynamic thermal equilibrium algorithm," which not only focuses on the center and edges but also dynamically generates a "viscosity field" distribution that is opposite to the temperature field distribution based on real-time thermal imaging data.

[0119] This application also provides a lithium-ion battery, wherein the lithium-ion battery is filled with a self-adjusting viscosity electrolyte as described in any of the foregoing embodiments, or the lithium-ion battery integrates an electrolyte microfluidic distribution system as described in any of the foregoing embodiments.

[0120] This lithium-ion battery typically comprises a positive electrode, a negative electrode, a separator between the positive and negative electrodes, and a packaging shell (such as an aluminum-plastic film or a metal casing). Its core feature is that it is filled with an electrolyte with self-regulating viscosity characteristics, or it integrates a microfluidic distribution system (including microchannels, sensor arrays, and actuators) that can dynamically control the distribution of the electrolyte. In terms of battery type, it can include, but is not limited to, pouch cells, prismatic aluminum-cased cells, cylindrical cells (such as 18650, 21700, or 46800 models), and coin cells. In terms of application system, it can cover common lithium cobalt oxide batteries, ternary material (NCM / NCA) batteries, lithium iron phosphate (LFP) batteries, and any secondary battery system that uses a liquid electrolyte, such as solid-liquid hybrid batteries or semi-solid batteries that may be used in the future.

[0121] This application also provides an electrical device, including a lithium-ion battery as described in the foregoing embodiments.

[0122] The term "electrical equipment" refers to any device that uses the aforementioned lithium-ion batteries as a power source or energy storage component. Its applications are very broad, including but not limited to: (1) mobile electronic devices: such as smartphones, tablets, laptops, smartwatches, Bluetooth headsets, VR / AR glasses, etc.; (2) electric vehicles: such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs / PHEVs), electric bicycles, electric scooters, balance bikes, and electric drones, etc.; (3) energy storage systems: such as home energy storage power supplies, outdoor portable power supplies, backup power supplies for communication base stations, and large-scale grid-level energy storage power stations; (4) power tools and others: such as electric drills, lawnmowers, robot vacuum cleaners, and various smart home devices. These devices, due to the adoption of the aforementioned advanced battery technology, have achieved significant improvements in fast charging capability, operational stability under extreme temperatures, and safety.

[0123] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present invention in any way.

[0124] I. Experimental Example A: This experimental example A focuses on verifying the physicochemical properties (viscosity changes with temperature / potential) of electrolytes with different formulations to support the limitations on electrolyte component content and viscosity parameters in the implementation method.

[0125] 1. Electrolyte physicochemical properties test: (1) Preparation of experimental samples: Basic electrolyte: In a dry glove box, dissolve 1M lithium hexafluorophosphate (LiPF6) in a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 1:4.

[0126] Self-adjusting viscosity additive: The four-armed star-shaped block copolymer (containing PNIPAM temperature-sensitive arm, PEO-Fc electrochemical response arm and PEO ion-conducting arm) is synthesized and added to the base electrolyte in different mass percentages, while an equimolar amount of cyclodextrin is added.

[0127] (2) Sample setup: Example A1: Additive content 5 wt%.

[0128] Example A2: Additive content 10 wt%.

[0129] Example A3: Additive content 15 wt%.

[0130] Comparative Example DA1: Blank electrolyte without any additives.

[0131] Comparative example DA2: 10 wt% of conventional linear PNIPAM polymer (temperature-sensitive only, without electrochemical response arms and ion conduction arms).

[0132] 2. Testing Method: (1) Viscosity test: The viscosity of each sample was tested under different conditions using a rotational rheometer.

[0133] (2) Room temperature test: The temperature is controlled at 25℃, and the shear viscosity is tested.

[0134] (3) High temperature test: The temperature is controlled at 45℃, and the shear viscosity is tested (to verify the temperature sensitivity).

[0135] (4) Electric field response test: At 25°C, a DC voltage of 4.3V was applied to the sample, and the viscosity was tested after stabilization (to verify the electrochemical responsiveness).

[0136] 3. Test Results and Analysis: Table 1. Test results of the physicochemical properties of the electrolyte

[0137] analyze: The data from Examples A1-A3 fully demonstrate that the electrolyte of the present invention can achieve the characteristics of "low viscosity at 25°C (5-10 cP range or near)", "high viscosity at 45°C (40-60 cP range or near)" and "viscosity doubling under high voltage" in the range of 5-15 wt%.

[0138] II. Experimental Example B: This experimental example B focuses on verifying the application effect of the microfluidic distribution system integrating the electrolyte at the full-cell level.

[0139] 1. Experimental platform setup: Battery type: 50Ah NCM811 / graphite pouch battery.

[0140] System Configuration: Integrated distributed sensor array (including Li reference electrode).

[0141] Microfluidic actuator: Reservoir A is loaded with basic electrolyte, and reservoir B is loaded with concentrated mother liquor containing 30wt% additives.

[0142] Control unit: Pre-installed with an AI decision-making model, with a concentration polarization voltage threshold set to 80mV.

[0143] 2. Test grouping and control strategies: (1) Example B1 (System of the present invention - room temperature fast charging): 25℃ environment, 1C-5C fast charging.

[0144] The strategy is that when the polarization voltage exceeds the threshold, the AI ​​command adjusts the mixing ratio to make the equivalent additive concentration of the injected electrolyte 10wt%.

[0145] (2) Example B2 (System of the present invention - low temperature charging): -10℃ environment, 3C charging.

[0146] The strategy is that the AI ​​identifies low temperature and instructs to reduce the proportion of liquid B, so that the equivalent additive concentration of the injected electrolyte is only 2wt% (close to the pure base liquid).

[0147] (3) Example B3 (System-Module Thermal Management of the Invention): Simulates an uneven temperature field with a center temperature of 48°C and an edge temperature of 35°C.

[0148] The strategy is to perform differentiated injection, injecting a high-viscosity liquid (equivalent to 15wt% additive) into the central area and a low-viscosity liquid (equivalent to 5wt% additive) into the edge area.

[0149] (4) Comparative example DB1 (ordinary battery): Only commercially available electrolyte with a fixed formula was injected (same as DA1).

[0150] (5) Comparative example DB2 (PTC battery): Injected with an electrolyte containing 10wt% conventional PTC polymer (same as DA2).

[0151] 3. Test Results and Analysis: Table 2. Battery System Performance Test Results

[0152] Results analysis: (1) In terms of fast charging kinetics (B1 vs DB1 / DB2), Example B1 exhibited a concentration polarization of only 15 mV under 5C fast charging, significantly better than Comparative Example DB1 (105 mV). This is attributed to the moderate adhesion enhancement of the electrochemical response arm at high potential, which protects the interface, while the ion-conducting arm ensures unobstructed transport channels. In contrast, although Comparative Example DB2 has PTC adhesion enhancement, it lacks ion-conducting design, resulting in a still relatively high polarization (80 mV).

[0153] (2) Regarding low-temperature adaptability (B2 vs DB2), Example B2 utilizes a microfluidic system to actively reduce the additive concentration at low temperatures, achieving an 88% capacity retention rate. In contrast, the PTC polymer in Comparative Example DB2, even without phase change at low temperatures, suffers from severe ion migration due to its inherently high molecular weight, resulting in a capacity retention rate of only 50% (low-temperature performance collapse). This demonstrates the significant advantage of the "on-demand formulation" method of this invention.

[0154] (3) Thermal equilibrium capability (B3 vs DB1): Example B3 successfully controlled the module temperature difference at 3℃ (comparative example DB1 was 15℃) through a differentiated injection strategy at the center / edge, and had the lowest gas production. This directly verifies the significant effect of the technical feature of "the injection ratio in the center area is higher than that in the edge area" in solving thermal runaway and extending module life.

[0155] In summary, the technical solution of this invention not only achieves dual adaptive adjustment of viscosity at the material level, but also achieves precise and dynamic control of the internal microenvironment of the battery at the system level, comprehensively solving the problem of the inability to achieve both safety and fast charging in the prior art.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-regulating viscosity electrolyte, characterized by, The electrolyte includes a base electrolyte, cyclodextrin, and a self-adjusting viscosity additive; The self-adjusting viscosity additive comprises a four-armed star-shaped block copolymer; The four-armed star-shaped block copolymer has three functional arms: a temperature-sensitive arm, an electrochemically responsive arm, and an ion-conducting arm. Wherein, the temperature-sensitive arm is a polymer chain segment with a low critical dissolution temperature; The electrochemical response arm contains a ferrocene group; The ion-conducting arm is a polyether-based chain segment.

2. The self-adjusting viscosity electrolyte as described in claim 1, characterized in that, The temperature-sensitive arm is a poly(N-isopropylacrylamide) segment; and / or, The ion-conducting arm is a polyoxyethylene segment; and / or... The electrochemical response arm is a polyoxyethylene segment containing ferrocene side groups; and / or, The lower critical dissolution temperature of the temperature-sensitive arm is 30℃~35℃; and / or, The electrochemical response arm is in an oxidized state and undergoes hydrophobic aggregation at a potential above 4V; and / or, Based on the total weight of the electrolyte, the mass percentage of the self-adjusting viscosity additive is 5wt%~15wt%.

3. The self-adjusting viscosity electrolyte as described in claim 1, characterized in that, The basic electrolyte includes lithium salt and organic solvent; Preferably, the lithium salt comprises lithium hexafluorophosphate; Preferably, the organic solvent includes ethylene carbonate and ethyl methyl carbonate; Preferably, the volume ratio of ethylene carbonate to methyl ethyl carbonate is 2:8 to 4:

6.

4. The self-adjusting viscosity electrolyte as described in claim 1, characterized in that, The viscosity of the electrolyte is 5 cP to 10 cP at 25°C; the viscosity is 40 cP to 60 cP at 45°C; and the viscosity of the electrolyte increases by at least 100% when the potential is higher than 4V.

5. An electrolyte microfluidic distribution system, characterized in that, The system is configured to inject a self-adjusting viscosity electrolyte as described in any one of claims 1-4 into the battery. The electrolyte microfluidic distribution system includes: A distributed sensor array is used to monitor local temperature and impedance inside the battery; The microfluidic actuator includes a reservoir for storing a base electrolyte and a self-adjusting viscosity additive concentrate, a micro mixer, and a piezoelectric microvalve. The control unit is used to calculate the required electrolyte viscosity for the target area based on the local temperature and impedance, and to control the opening degree of the micromixer and the piezoelectric microvalve.

6. The electrolyte microfluidic distribution system as described in claim 5, characterized in that, The control unit has a pre-stored AI decision model; the AI ​​decision model is constructed by establishing a four-dimensional mapping relationship between electrolyte viscosity, temperature, current, and ionic conductivity, and setting a concentration polarization voltage threshold; the control unit is configured to: when the calculated concentration polarization voltage exceeds the threshold, output a control command to increase the proportion of self-adjusting viscosity additive; and / or, The micromixer is a Y-type micromixer; and / or, The microfluidic actuator delivers electrolyte through microchannels embedded inside the battery, the width of which is 100μm~300μm; and / or, The response time of the piezoelectric microvalve is less than 20ms; and / or, The impedance sensor in the distributed sensor array is a three-electrode impedance sensor containing a lithium reference electrode, used to monitor the concentration polarization impedance at the electrode interface.

7. A method for adaptive viscosity control of a fast-charging battery based on the electrolyte microfluidic distribution system according to any one of claims 5-6, characterized in that, include: Collect local temperature and impedance data inside the battery; The local temperature data and impedance data are input into a preset decision model; The decision model is based on the coupling relationship between viscosity, temperature, current and conductivity, and aims to minimize concentration polarization to calculate the optimal viscosity value required for the target region. Based on the optimal viscosity value, calculate the mixing ratio of the base electrolyte and the self-adjusting viscosity additive concentrate; Adjust the opening of the piezoelectric microvalve in the microfluidic actuator, mix according to the specified mixing ratio, and then inject into the target area of ​​the battery.

8. The fast-charging battery viscosity adaptive control method as described in claim 7, characterized in that, Also includes: When the temperature in the central region of the battery module is detected to be higher than that in the edge region, and the temperature difference exceeds a preset threshold, the control unit controls the proportion of self-adjusting viscosity additive in the electrolyte injected into the central region to be higher than that injected into the edge region.

9. A lithium-ion battery, characterized in that, The lithium-ion battery is filled with a self-adjusting viscosity electrolyte as described in any one of claims 1-4, or the lithium-ion battery integrates an electrolyte microfluidic distribution system as described in any one of claims 5-6.

10. An electrical-related device, characterized in that, Including the lithium-ion battery as described in claim 9.

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