Fluid supplement capsule, method of making and using same, battery, device

Abstract

This application provides a replenishment bladder, its preparation method and application, battery, and device, relating to the field of battery technology. The rupture pressure threshold of the replenishment bladder's shell can be reduced under the influence of environmental changes during the later stages of battery cycling. Thus, even when the internal pressure of the battery has not increased, but the internal environment changes due to battery cycling, the bladder ruptures and releases liquid substances, effectively replenishing the electrolyte or additives consumed during battery cycling. Therefore, this application can avoid the side reactions and increased internal resistance exacerbated by excessive electrolyte, slow down the rate of battery capacity decay, and extend the battery's cycle life.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a fluid replenishment bag, its preparation method and application, battery, and device. Background Technology

[0002] In the later stages of battery cycling, the electrolyte or additives inside the battery decrease, leading to accelerated battery capacity decay.

[0003] Currently, the common strategy is to increase the initial electrolyte content inside the battery. However, excessive electrolyte can exacerbate side reactions inside the battery and lead to increased internal resistance. Summary of the Invention

[0004] This application provides a electrolyte replenishment bag, its preparation method and application, a battery, and a device. Its main purpose is to solve the problem that excessive electrolyte can exacerbate side reactions within the battery and lead to increased internal resistance.

[0005] According to a first aspect of this application, a fluid resuscitation bag is provided, comprising:

[0006] The capsule has a cavity inside, which contains a liquid substance containing the same or partially the same components as the electrolyte. The capsule is designed to rupture when the pressure on the fluid replenishment capsule is not less than the rupture pressure threshold, so that the liquid material inside the capsule can flow out of the capsule. The rupture pressure threshold is reduced by changes in the environment in which the fluid replenishment capsule is located, including at least changes in temperature and / or chemical environment.

[0007] In some embodiments of this application, the initial value of the rupture pressure threshold is between 1 MPa and 6 MPa, wherein the initial value of the rupture pressure threshold is determined by the material of the bladder shell, the radius of the fluid replenishment bladder, and the thickness of the bladder shell.

[0008] In some embodiments of this application, the capsule shell of the fluid replenishment bladder is made of a biodegradable polymer material, which causes the capsule shell to degrade over time after rupture.

[0009] In some embodiments of this application, the elastic modulus of the shell decreases with increasing temperature, resulting in a lower rupture pressure threshold at higher temperatures; and / or, The hydrolysis rate of the capsule is accelerated under the influence of an acidic environment, which makes the rupture pressure threshold smaller the higher the acidity of the environment.

[0010] In some embodiments of this application, the biodegradable polymeric material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate.

[0011] In some embodiments of this application, the liquid substance contains at least one of the following additives: fluoroethylene carbonate (FEC), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB).

[0012] In some embodiments of this application, the thickness of the capsule shell is 200 nm to 1000 nm; or / and, The average radius of the infusion bag is 5 μm to 50 μm; The thickness of the capsule shell and the average radius of the fluid replenishment capsule are determined by the process parameters of the fluid replenishment capsule preparation process. The process parameters include at least one of the following: emulsification speed, polymer concentration, and solvent evaporation rate.

[0013] According to a second aspect of this application, a method for preparing a fluid replenishment bag is provided, wherein the fluid replenishment bag is the fluid replenishment bag described in the first aspect above, and the preparation method includes: Preparation of capsules containing liquid substances; The capsule shell is dried to obtain the fluid replenishment capsule.

[0014] In some embodiments of this application, the shell is made of a biodegradable polymer material, the mechanical properties of which decrease under heating or electrochemical action; The fluid replenishment bladder is designed such that when the pressure it withstands reaches the rupture pressure threshold, the bladder shell ruptures and releases liquid substances. The rupture pressure threshold decreases as the mechanical properties of the degradable polymer material decrease.

[0015] In some embodiments of this application, the preparation of a capsule containing a liquid substance includes: Degradable polymeric materials are dissolved in volatile solvents to obtain polymer oil phase solutions; A composite emulsion is obtained by mixing a polymer oil phase solution with a liquid substance and then emulsifying the mixture. The volatile solvents in the complex emulsion are evaporated to obtain a capsule containing liquid substances.

[0016] In some embodiments of this application, the biodegradable polymeric material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate; In polylactic acid-polymethyl methacrylate copolymers, the ratio of polylactic acid to polymethyl methacrylate is between 3:7 and 7:3.

[0017] In some embodiments of this application, the volatile solvent is dichloromethane (DCM); or / and, The mass fraction of the polymer oil phase solution ranges from 5% to 20% w / v; the higher the mass fraction of the polymer oil phase solution, the thicker the capsule shell.

[0018] In some embodiments of this application, the polymer oil phase solution is mixed with a liquid substance and then emulsified to obtain a composite emulsion, including: Using an aqueous solution containing emulsifier as the continuous phase, a polymer oil phase solution is mixed with a liquid substance and then subjected to high-speed shear emulsification to obtain a composite emulsion.

[0019] In some embodiments of this application, the emulsifier is polyvinyl alcohol (PVA), and the mass fraction of the emulsifier is between 1% and 2%; or / and, When the polymer oil phase solution is mixed with the liquid substance, the volume ratio of the polymer oil phase solution to the liquid substance is between 3:1 and 5:1; or / and, The rotation speed of high-speed shear emulsification is between 8000 rpm and 15000 rpm. The faster the rotation speed of high-speed shear emulsification, the smaller the radius of the replenishment bladder.

[0020] In some embodiments of this application, the volatile solvent in the composite emulsion is evaporated to obtain a capsule containing liquid substances, comprising: The volatile solvents in the volatile composite emulsion cause the biodegradable polymer material to be deposited and precipitated on the surface of the liquid substance, resulting in a capsule containing the liquid substance.

[0021] In some embodiments of this application, the volatile solvents in the volatile complex emulsion include: The composite emulsion was stirred in a water bath to allow the volatile solvents to evaporate. The water bath temperature is between 30°C and 40°C, and the stirring speed is between 300 rpm and 500 rpm.

[0022] According to a third aspect of this application, a diaphragm is provided, wherein the fluid replenishment bladder of the first aspect is applied to the diaphragm, the diaphragm comprising a base membrane and a coating applied to the surface of the base membrane; The coating comprises a replenishment capsule dispersed in an aprotic solvent and a binder.

[0023] In some embodiments of this application, the adhesive is polyvinylidene fluoride (PVDF); or / and, The mass ratio of the fluid replenishment bladder to the binder in the coating is between 20:80 and 30:70; or / and, The aprotic solvent is N-methylpyrrolidone (NMP).

[0024] According to a fourth aspect of this application, a battery is provided, wherein the battery includes the liquid replenishment bladder of the first aspect or the diaphragm of the third aspect described above.

[0025] According to a fifth aspect of this application, an apparatus is provided, wherein the apparatus includes the battery described in the fourth aspect above.

[0026] The electrolyte replenishment bladder, its preparation method, application, battery, and device provided in this application have a rupture pressure threshold that can be reduced under environmental changes during the later stages of battery cycling. This allows the bladder to rupture and release liquid substances even when the internal pressure of the battery has not increased, due to changes in the internal environment caused by battery cycling. This effectively replenishes the electrolyte or additives consumed during battery cycling. Therefore, this application can avoid the side reactions and increased internal resistance exacerbated by excessive electrolyte, slow down the rate of battery capacity decay, and extend the battery's cycle life.

[0027] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0028] The accompanying drawings are provided for a better understanding of this solution and do not constitute a limitation of this application. Wherein: Figure 1 This is a schematic diagram of the structure of a fluid infusion bag provided in an embodiment of this application; Figure 2 A method for preparing a fluid infusion bag provided in the embodiments of this application; Figure 3 This is a schematic diagram of the cross-sectional structure of a diaphragm provided in an embodiment of this application. Detailed Implementation

[0029] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0030] As lithium-ion batteries reach the later stages of their lifespan, the total amount of electrolyte or key additives often depletes, leading to accelerated performance degradation. Specifically, in the later stages of battery cycling, the internal expansion force increases dramatically. This expansion force originates from the continuous thickening of the solid electrolyte interfacial film and gas generation within the battery. Under the pressure of this expansion force, the electrolyte migrates from areas of high pressure to areas of low pressure, causing localized drying zones in high-pressure areas (such as the negative electrode interface), which in turn triggers lithium plating. Simultaneously, the depletion of key film-forming additives in the later stages of cycling accelerates side reactions in the solid electrolyte interfacial film, resulting in a doubling of the battery capacity decay rate.

[0031] Therefore, this application provides a fluid replenishment sac, which is a miniature container that internally encapsulates a functional liquid and is capable of releasing the functional liquid in response to specific external stimuli.

[0032] The following description, with reference to the accompanying drawings, describes the fluid replenishment bag, its preparation method and application, battery, and device according to embodiments of this application.

[0033] Figure 1 This is a schematic diagram of the structure of a fluid replenishment bag provided in an embodiment of this application.

[0034] like Figure 1 As shown, the fluid resuscitation bag includes: The capsule has a cavity inside, which contains a liquid substance containing the same or partially the same components as the electrolyte. The capsule is designed to rupture when the pressure on the fluid replenishment capsule is not less than the rupture pressure threshold, so that the liquid material inside the capsule can flow out of the capsule. The rupture pressure threshold is reduced by changes in the environment in which the fluid replenishment capsule is located, including at least changes in temperature and / or chemical environment.

[0035] In the embodiments of this application, the shell constitutes the external structure of the replenishment bladder, primarily used to isolate the liquid substance inside the bladder from the external environment, thereby preventing premature leakage or unintended interactions between the liquid substance and other components inside the battery. In one possible embodiment, the shell is made of a material with specific mechanical properties and environmental sensitivity characteristics, such as a biodegradable polymer material.

[0036] The liquid substance contains components that are the same as or partially the same as the electrolyte. The electrolyte is a liquid medium inside the battery used for ion conduction, typically containing lithium salts and organic solvents, and is an essential component for the normal operation of the battery. In this application, the liquid substance is encapsulated inside a casing as a component to be replenished to the electrolyte inside the battery.

[0037] In this application, the rupture pressure threshold is a pre-set critical pressure value, representing the minimum pressure required for the electrolyte reservoir to undergo structural failure under external force. When the local pressure of the environment in which the electrolyte reservoir is located is below this rupture pressure threshold, the reservoir can maintain its structural integrity based on its own mechanical strength, ensuring the sealing of the internal electrolyte. When the local pressure reaches or exceeds this rupture pressure threshold, the internal stress of the reservoir material exceeds its strength limit, causing the reservoir structure to disintegrate, thereby releasing the electrolyte contained within into the external environment. It should also be noted that the rupture pressure threshold is designed to match the local mechanical stress generated during the later stages of battery cycling due to electrode volume expansion and gas production.

[0038] In one possible embodiment, the burst pressure threshold decreases under the influence of changes in temperature and / or chemical environment. The effect of temperature change can be an increase in temperature, which refers to the local temperature rise caused by the Joule heating effect resulting from increased internal resistance during battery operation or by an increase in external ambient temperature. The effect of changes in chemical environment refers to the side reactions such as oxidative decomposition of electrolyte components during battery charging and discharging, such as under high-voltage conditions, generating protons or Lewis acid products, thereby altering the local chemical microenvironment at the electrode or separator interface. The factors affecting the burst pressure threshold can be temperature increase, changes in electrochemical environment, or a combination of both.

[0039] Specifically, the fluid replenishment bladder of this application utilizes the physicochemical properties of the bladder shell material to achieve a change in the rupture pressure threshold. When the battery experiences a temperature rise during the later stages of cycling, the elastic modulus of the bladder shell material decreases due to thermal softening, resulting in a decrease in the actual mechanical strength of the bladder shell and consequently a reduction in the critical pressure value required for rupture. Simultaneously, when the electrochemical environment deteriorates during the later stages of cycling (e.g., electrolyte decomposition at high voltage producing acidic substances), the chemical bonds (e.g., ester bonds) in the bladder shell material undergo hydrolysis and chain scission reactions in this acidic microenvironment, leading to a decrease in the molecular weight and deterioration of the mechanical properties of the bladder shell material, which further reduces the actual rupture pressure value. Therefore, both temperature rise and electrochemical environmental factors can independently or synergistically weaken the bladder shell material, thereby dynamically lowering the initially designed rupture pressure threshold.

[0040] The electrolyte replenishment bladder provided in this application has a rupture pressure threshold that decreases under the influence of temperature or chemical environment during the later stages of battery cycling. This allows the bladder to rupture and release liquid substances even when the internal battery pressure has not increased, due to temperature or electrochemical environment changes caused by battery cycling. This effectively replenishes the electrolyte or additives consumed during battery cycling. Therefore, this application can avoid the side reactions and increased internal resistance exacerbated by excessive electrolyte, slow down the rate of battery capacity decay, and extend the battery's cycle life.

[0041] In one possible implementation of this application embodiment, the initial value of the rupture pressure threshold is between 1 MPa and 6 MPa, wherein the initial value of the rupture pressure threshold is determined by the material of the bladder shell, the radius of the fluid replenishment bladder, and the thickness of the bladder shell.

[0042] In the embodiments of this application, the rupture pressure threshold is a dynamically changing critical value that decreases under heating or electrochemical effects. However, it is necessary to set the numerical range of the rupture pressure threshold in the initial state before being affected by heating or electrochemical effects.

[0043] In this application, the initial value of the rupture pressure threshold refers to the inherent critical value of the rupture pressure of the bladder shell when the fluid replenishment bladder has not experienced significant heating or electrochemical environmental degradation. It is a reference value that is dynamically adjusted downwards due to subsequent heating or electrochemical effects.

[0044] It should be noted that setting the initial value within the range of 1MPa to 6MPa ensures that the pressure is higher than the normal electrode expansion pressure (usually lower than 1MPa) in the early stages of battery cycling, thereby avoiding premature rupture of the electrolyte reservoir due to normal volume changes. At the same time, the upper limit of 6MPa in this range ensures that in the later stages of battery cycling, when the reservoir shell weakens due to thermal softening and chemical degradation, the actual rupture threshold can be reduced to a level that matches the accumulated electrode expansion stress, thereby achieving precise release of electrolyte.

[0045] The initial value of the rupture pressure threshold is determined by the radius of the fluid-filled bladder and the thickness of the bladder shell. The radius of the fluid-filled bladder is the distance from the geometric center of the bladder to its outermost surface; when the bladder is approximately spherical, the radius determines the curvature of the bladder shell. The thickness of the bladder shell is the perpendicular distance from the inner surface to the outer surface of the bladder shell. Given a fixed Young's modulus (i.e., the inherent stiffness of the material) of the bladder shell material, a definite mechanical relationship exists between the initial value of the rupture pressure threshold and the bladder shell thickness and bladder radius.

[0046] Specifically, the relationship between the initial value of the rupture pressure threshold and the capsule thickness and radius can be explained by, but is not limited to, the following formula (1): P ∝ E × (h / R)² Where P is the critical pressure that the capsule can withstand, i.e. the rupture pressure threshold, E is the Young's modulus of the capsule material itself, h is the thickness of the capsule, and R is the radius of the fluid replenishment capsule.

[0047] Therefore, it can be shown that, given a fixed shell material, a greater shell thickness results in higher mechanical strength of the fluid-filled bladder and a higher initial rupture pressure threshold; conversely, a smaller shell thickness leads to a lower initial rupture pressure threshold. Simultaneously, a larger bladder radius makes the shell more prone to deformation under the same pressure, thus resulting in a lower initial rupture pressure threshold; a smaller radius leads to a more stable structure and a higher initial rupture pressure threshold. Therefore, given a fixed shell material, by independently adjusting the radius and thickness of the fluid-filled bladder, an initial rupture pressure threshold can be designed within the range of 1 MPa to 6 MPa.

[0048] It should be further noted that, according to the above formula, the initial value of the rupture pressure threshold for different bladder materials is as follows: when the radius of the fluid replenishment bladder and the thickness of the bladder shell are fixed, the higher the Young's modulus of the bladder shell material itself, the larger the initial value of the rupture pressure threshold; conversely, the lower the Young's modulus of the bladder shell material itself, the lower the initial rupture pressure threshold.

[0049] In one possible implementation of this application, the shell of the fluid replenishment bladder is made of a biodegradable polymer material, so that the shell degrades over time after rupture.

[0050] In the embodiments of this application, the biodegradable polymer material refers to a polymer material that, under specific environmental conditions (e.g., the action of trace amounts of moisture, acidic byproducts, or enzymes inside the battery), undergoes molecular weight reduction and loss of mechanical properties through the breaking of chemical bonds on its main chain, and ultimately decomposes into small molecule products (such as lactic acid, carbon dioxide, and water). Its degradation products are environmentally friendly and relatively inert to the battery's chemical system. Furthermore, the ruptured shell degrades over time, preventing permanent physical blockage within the battery.

[0051] In one possible embodiment, the capsule shell, made of a biodegradable polymer material, also includes, but is not limited to, the following characteristics: The elastic modulus of the capsule decreases with increasing temperature, resulting in a lower rupture pressure threshold at higher temperatures; and / or, The hydrolysis rate of the capsule is accelerated under the action of an acidic environment, which makes the higher the concentration of acidic substances in the environment, the lower the rupture pressure threshold.

[0052] In the embodiments of this application, the elastic modulus is a physical quantity characterizing the ability of a solid material to resist elastic deformation. The higher the value, the greater the stiffness of the material, and the smaller the deformation under the same external force. The decrease in elastic modulus under increasing temperature leads to a decrease in the burst pressure threshold. That is, the higher the temperature, the greater the decrease in the elastic modulus of the shell material, and therefore the smaller the burst pressure threshold.

[0053] In this application, the hydrolysis rate refers to the reaction rate at which hydrolyzable chemical bonds (e.g., ester bonds in the main chain of polylactic acid) in the shell material break down with the participation of water.

[0054] In one possible embodiment, the concentration of acidic substances in the environment can be determined by trace amounts of protons H. + The concentration of other acidic substances is determined, and trace protons H are also considered. + This refers to the acidic byproducts generated by the oxidative decomposition of organic solvents or additives in the electrolyte under high-voltage conditions. Essentially, these are positively charged hydrogen ions. Specifically, in trace amounts of protons (H+)... + In the acidic microenvironment, the hydrolysis rate of the shell material is faster than in a neutral environment, leading to accelerated breakage of the shell polymer chains, a rapid decrease in molecular weight, and consequently, a reduction in mechanical strength and a decrease in the rupture pressure threshold. Specifically, the rate of hydrolysis is higher in trace protons (H). + The higher the concentration, the faster the degradation rate of the shell material, the more severe the deterioration of its mechanical properties, and thus the smaller the rupture pressure threshold.

[0055] In a preferred embodiment, the biodegradable polymeric material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate.

[0056] Specifically, the changes in elastic modulus, hydrolysis rate, and fracture pressure threshold can also be illustrated using, but are not limited to, the following possible examples: Before environmental factors intervene, the initial mechanical parameters (initial elastic modulus E0, wall thickness h) of the bladder determine the initial value of the rupture pressure threshold, namely P (range of 1 MPa–6 MPa). In the early stages of battery cycling, the normal electrode expansion pressure (approximately 0.5 MPa–1 MPa) is far lower than the initial value of the rupture pressure threshold, and the fluid replenishment bladder remains intact.

[0057] Synergistic weakening of the thermal environment: As the number of battery cycles increases, the internal resistance increases, leading to the Joule heating effect and causing a local temperature rise, such as to 45–60°C. The elastic modulus E of the PLA / PMMA shell decreases due to thermal softening. E T (E) T = E0 × [1 - α(T - T0)] Where α is a temperature coefficient, such as 0.5%–1% / ℃, T is the current temperature, and T0 is the initial temperature. The actual rupture threshold is reduced to PT = P × (ET / E0)0.5, for example, a reduction of approximately 10%–30% compared to the initial value of the rupture pressure threshold.

[0058] Electrochemical environmental synergistic degradation: In the later stages of battery cycling, the electrolyte undergoes oxidative decomposition at high voltages (e.g., under conditions >4.3V), generating trace amounts of protons (H). + () or Lewis acidic products, causing a local pH decrease at the electrode / diaphragm interface. The ester bond hydrolysis rate of PLA increases with H. + Increased concentration and temperature accelerate the process. After continuous cycling (e.g., approximately 200–500 cycles), the average molecular weight of the shell material decreases (e.g., by 15%–30%), resulting in a corresponding decrease in the tensile strength of the shell (e.g., by 10%–25%), further reducing the actual rupture threshold.

[0059] It should be noted that the combined effects of temperature softening and chemical degradation mean that when the overall battery degradation reaches a certain level (i.e. when the need for replenishment is most urgent), the actual rupture threshold of the replenishment bladder is exactly matched with the electrode expansion stress accumulated in the later stages of cycling. This achieves adaptive and precise triggering, which is especially suitable for scenarios where chemical degradation is dominant (additive depletion, excessive SEI) but mechanical pressure alone has not yet reached the design threshold.

[0060] In a preferred embodiment, the liquid substance contains at least one of the following additives: fluoroethylene carbonate (FEC), vinylene carbonate (VC), and lithium difluoro(oxalato)borate (LiDFOB).

[0061] In the embodiments of this application, the liquid substance adopts a solid electrolyte interphase (SEI) repair electrolyte formulation, and its composition is compatible with the main electrolyte of the battery.

[0062] In a preferred embodiment, the thickness of the capsule shell is 200 nm to 1000 nm; or / and, The average radius of the fluid infusion bag is 5 μm to 50 μm.

[0063] The thickness of the capsule shell and the average radius of the fluid replenishment capsule are determined by the process parameters of the fluid replenishment capsule preparation process. The process parameters include at least one of the following: emulsification speed, polymer concentration, and solvent evaporation rate.

[0064] In the embodiments of this application, by precisely controlling process parameters such as emulsification speed, polymer concentration, and solvent evaporation rate, the shell thickness (200nm to 1000nm) and the average radius of the replenishment bladder (5μm to 50μm) are precisely controlled, and the basic rupture pressure threshold is set in the range of 1 MPa to 6 MPa.

[0065] In one possible implementation of this application, this application also provides a method for preparing a fluid replenishment bag. Figure 2 This is a schematic flowchart illustrating the preparation method of the fluid replenishment bag provided in the embodiments of this application.

[0066] like Figure 2 As shown, the fluid resuscitation bag is Figure 1 The preparation method of the fluid replenishment bag described herein includes the following steps: Step 201: Prepare a capsule containing liquid material.

[0067] In the embodiments of this application, the preparation of a capsule containing liquid material refers to the process of forming a continuous and dense solid polymer encapsulation layer around tiny droplets of liquid material by physical or chemical means.

[0068] The goal is to achieve complete encapsulation of the liquid substance by the shell material, ensuring that the liquid substance is effectively sealed inside the replenishment capsule during storage and use. It should be noted that the shell preparation must be completed without compromising the chemical stability of the liquid substance (e.g., avoiding high temperatures or violent chemical reactions), ensuring the shell is formed and cured.

[0069] Step 202: Dry the capsule shell to obtain the fluid replenishment capsule.

[0070] In the embodiments of this application, drying refers to the process of separating the intermediate product of the replenishment bladder, which has already formed a shell, and removing impurities such as residual solvents, moisture, or emulsifiers from its surface or interior. Drying can be achieved in various ways, such as vacuum drying in a vacuum drying oven at an appropriate temperature, or using processes like freeze drying or spray drying. The purpose of this drying process is to improve the density and mechanical strength of the shell, while preventing residual solvents or moisture from adversely affecting the electrochemical system in subsequent battery applications. After drying, a replenishment bladder that can be directly used for battery separator coating is obtained.

[0071] In one example, the microcapsules obtained after preparing the capsule shell containing liquid can be filtered and collected, washed three times with deionized water, and then dried in a vacuum drying oven at 40°C for 12 h to obtain a final product with uniform particle size and intact capsule shell, namely a liquid replenishment capsule.

[0072] In one possible implementation of this application embodiment, the shell is made of a biodegradable polymer material, and the mechanical properties of the biodegradable polymer material decrease under the action of heating or electrochemistry. The fluid replenishment bladder is designed such that when the pressure it withstands reaches the rupture pressure threshold, the bladder shell ruptures and releases liquid substances. The rupture pressure threshold decreases as the mechanical properties of the degradable polymer material decrease.

[0073] In the embodiments of this application, mechanical properties refer to the mechanical behavior characteristics exhibited by a material under stress, including but not limited to parameters such as the material's elastic modulus, tensile strength, and fracture toughness. Mechanical properties determine the shell's ability to resist external pressure and rupture; that is, the magnitude of the rupture pressure threshold is related to the mechanical properties.

[0074] Specifically, regarding the changes in rupture pressure threshold and mechanical properties with increasing temperature or electrochemical properties, please refer to the above. Figure 1 The instructions for the fluid replenishment capsule are omitted here.

[0075] In one possible implementation of this application embodiment, the preparation of the capsule containing liquid substance can be achieved by, but is not limited to, the following methods: dissolving a biodegradable polymer material in a volatile solvent to obtain a polymer oil phase solution; mixing the polymer oil phase solution with the liquid substance and then emulsifying it to obtain a composite emulsion; evaporating the volatile solvent in the composite emulsion to obtain a capsule containing liquid substance.

[0076] In the embodiments of this application, volatile solvents refer to organic solvents with low boiling points that readily transform from liquid to gaseous state under normal temperature or mild heating conditions. These solvents serve as good solvents for biodegradable polymer materials, forming a homogeneous and transparent polymer solution. In a preferred embodiment, the volatile solvent may be dichloromethane (DCM). The polymer oil phase solution refers to a homogeneous liquid system consisting of the volatile solvent as the continuous phase and the biodegradable polymer material as the solute, serving as the raw material source for forming the capsule shell.

[0077] Emulsification is the process of dispersing one phase into the other phase in the form of tiny droplets by mechanical shearing force between two immiscible liquids (i.e., an oily polymer oil phase solution and a water-insoluble or lipophilic liquid substance).

[0078] In a preferred embodiment, a polymer oil phase solution and a liquid substance are mixed in a certain proportion. Under the action of a high-speed shear emulsification device, the liquid substance is broken into tiny droplets, each of which is surrounded by the polymer oil phase solution, forming a primary emulsion of water-in-oil (W / O). Subsequently, this primary emulsion is further dispersed into an external aqueous phase containing an emulsifier (e.g., an aqueous solution of polyvinyl alcohol (PVA)). After secondary emulsification, a composite emulsion of water-in-oil-in-electrolyte (W / O / E) is formed. In this composite emulsion, the innermost layer is the liquid substance droplets, the middle layer is the polymer oil phase containing dissolved polymer materials, and the outermost layer is the aqueous phase.

[0079] Finally, the evaporation step is typically carried out under conditions of gentle heating (e.g., a water bath at 30°C to 40°C) accompanied by slow stirring. As the volatile solvent gradually diffuses from the emulsion droplets into the aqueous phase and eventually evaporates into the gas phase, the solvent content in the polymer oil phase continuously decreases. This leads to a reduction in the solubility of the degradable polymer at the liquid droplet interface, thereby promoting the gradual deposition and aggregation of polymer chains at the liquid droplet interface, ultimately forming a solid film. Once the volatile solvent is completely removed, this solid film serves as a shell encapsulating the liquid substance, with the internal liquid substance completely encapsulated within this shell, thus obtaining a shell containing the liquid substance.

[0080] In a preferred embodiment, the biodegradable polymeric material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate; In polylactic acid-polymethyl methacrylate copolymers, the ratio of polylactic acid to polymethyl methacrylate is between 3:7 and 7:3.

[0081] In a preferred embodiment, the volatile solvent is dichloromethane (DCM); or / and, The mass fraction of the polymer oil phase solution ranges from 5% to 20% w / v; the higher the mass fraction of the polymer oil phase solution, the thicker the capsule shell.

[0082] In one example, PLA, PMMA, or a copolymer of PLA and PMMA (the PLA:PMMA mass ratio can be adjusted between 3:7 and 7:3 to balance flexibility and thermal stability) is dissolved in dichloromethane (DCM) to prepare a polymer oil phase solution with a mass fraction of 5%–20% w / v. Higher polymer concentrations result in thicker film walls and correspondingly higher trigger pressure thresholds; lower polymer concentrations result in thinner walls and lower thresholds.

[0083] It should be noted that by adjusting the PLA:PMMA mass ratio within the range of 3:7 to 7:3, the overall performance of the capsule shell can be flexibly designed. For example, when the PLA ratio is relatively high (e.g., close to 7:3), the copolymer exhibits a faster degradation rate, stronger acid-catalyzed hydrolysis sensitivity, and a relatively fast thermal softening response; when the PMMA ratio is relatively high (e.g., close to 3:7), the copolymer exhibits better film uniformity, higher mechanical toughness, and better dimensional stability.

[0084] In this application, the mass fraction of the polymer oil phase solution refers to the mass percentage of degradable polymeric material per unit volume of the polymer oil phase solution. %w / v is a way of expressing mass-volume percentage concentration; for example, 5%w / v means that 5 grams of degradable polymeric material are contained in every 100 ml of volatile solvent.

[0085] It should be further explained that controlling the mass fraction of the polymer oil phase solution within the range of 5% to 20% w / v ensures that the solution has sufficient viscosity to stably encapsulate the liquid droplets during emulsification, preventing droplet aggregation. Simultaneously, it avoids excessively high viscosity due to excessive concentration, which could affect the uniformity of emulsification and droplet size. When the mass fraction of the polymer oil phase solution is high, there are more polymer chains per unit volume of oil phase. These polymer chains will all deposit at the interface of the liquid droplets during solvent evaporation, thus forming a thicker capsule. Conversely, when the mass fraction is low, the total amount of deposited polymer material is less, and the resulting capsule thickness is correspondingly thinner.

[0086] In one possible implementation of this application embodiment, when emulsifying the polymer oil phase solution with a liquid substance to obtain a composite emulsion, it can be achieved in the following ways, but not limited to: using an aqueous solution containing an emulsifier as the continuous phase, mixing the polymer oil phase solution with the liquid substance and then performing high-speed shear emulsification to obtain a composite emulsion.

[0087] In the embodiments of this application, the emulsifier is an amphiphilic substance with both hydrophilic and lipophilic groups. Its function is to reduce the interfacial tension between the oil phase and the aqueous phase, and to form a protective film on the surface of the dispersed phase droplets, preventing collision and coalescence between droplets, thereby maintaining the stability of the emulsion. In this application, the emulsifier's role is to stabilize the structure of the composite emulsion, ensuring that during solvent evaporation, the liquid substance is encapsulated by the polymer oil phase, preventing phase separation or leakage.

[0088] An aqueous solution is a liquid system that uses water as the main solvent.

[0089] The continuous phase refers to the phase that constitutes the external continuous medium in an emulsion. In complex emulsions, the continuous phase is the outermost phase, which carries the dispersed phase droplets and provides a flow medium. In this application, the continuous phase is an aqueous solution containing an emulsifier, while the dispersed phase is a composite droplet of liquid substance encapsulated by a polymer oil phase.

[0090] High-speed shear emulsification refers to the process of using a high-speed rotating shear head or homogenizer to apply strong shearing, impact, and cavitation effects to a mixed liquid, thereby breaking one liquid into tiny droplets and dispersing them into another immiscible liquid.

[0091] In a preferred embodiment, the emulsifier is polyvinyl alcohol (PVA), and the mass fraction of the emulsifier is between 1% and 2%.

[0092] The mass fraction refers to the proportion of polyvinyl alcohol in the aqueous solution to the total mass of the aqueous solution. Controlling the mass fraction between 1% and 2% serves two purposes: it ensures that the aqueous phase has sufficient emulsifying ability to stabilize the fine droplets formed under high shear; and this concentration range will not cause the solution viscosity to be too high, thus affecting the emulsification effect or increasing the difficulty of subsequent washing and removal.

[0093] In a preferred embodiment, after mixing the polymer oil phase solution with the liquid substance, the volume ratio of the polymer oil phase solution to the liquid substance is between 3:1 and 5:1.

[0094] The volume ratio refers to the ratio of the volume of the polymer oil phase solution to the volume of the liquid substance. This ratio determines the relative relationship between the total amount of material used to form the capsule and the total amount of liquid substance being encapsulated during emulsification. Controlling the volume ratio between 3:1 and 5:1 ensures that sufficient polymer material is deposited on the surface of the liquid droplets to form a capsule, while avoiding excessively thick capsules or material waste due to an excessively high polymer oil phase ratio.

[0095] In a preferred embodiment, the rotation speed of high-speed shear emulsification is between 8000 rpm and 15000 rpm. The faster the rotation speed of high-speed shear emulsification, the smaller the radius of the replenishment bladder.

[0096] Here, rotational speed refers to the number of revolutions per minute of the rotor in a high-speed shear emulsification device. Rotational speed is a parameter that determines the shear strength and the degree of droplet fragmentation. Controlling the rotational speed within the range of 8000 rpm to 15000 rpm can generate sufficiently strong shear force to break the mixture of polymer oil phase and liquid substance into micron-sized or even submicron-sized droplets, thereby obtaining replenishment bladders of the desired size.

[0097] In one example, using a polyvinyl alcohol (PVA, 1%–2% by mass) aqueous solution as the continuous phase, the polymer oil phase is mixed with a liquid substance containing functional additives (FEC, VC, LiDFOB) at a volume ratio of 3:1–5:1 (oil phase:liquid substance), and then subjected to high-speed shear emulsification (8000–15000 rpm, 2–5 min) to form a stable W / O / E type multi-emulsion. The higher the emulsification speed, the finer the droplet dispersion and the smaller the resulting microcapsule particle size.

[0098] In one possible implementation of this application embodiment, when obtaining a capsule containing liquid substance by evaporating the volatile solvent in the composite emulsion, it can be achieved by, but is not limited to, the following method: evaporating the volatile solvent in the composite emulsion causes the degradable polymer material to be deposited on the surface of the liquid substance, thereby obtaining a capsule containing liquid substance.

[0099] In the embodiments of this application, evaporation refers to the process by which molecules of a liquid substance escape from the liquid surface and transform into a gaseous state before reaching its boiling point. In this application, volatile solvents are removed through evaporation by allowing the solvent to gradually diffuse and evaporate from the emulsion droplets under mild conditions, thereby altering the composition and environment inside the droplets.

[0100] Deposition refers to the process by which a solute in a dissolved state gradually precipitates from a solution due to the removal of the solvent and deposits on a specific interface to form a solid layer. In this application, the deposition process can be described as follows: As the volatile solvent gradually diffuses from the oil phase of the composite emulsion to the aqueous phase and eventually evaporates into the gas phase, the solubility of the degradable polymer material in the polymer oil phase continuously decreases, causing the polymer chains to reach a supersaturated state at the interface between the oil phase and the liquid core, thereby beginning to aggregate, entangle, and ultimately form a dense solid film at this interface.

[0101] In a preferred embodiment, when evaporating the volatile solvent in the composite emulsion, the composite emulsion can be stirred in a water bath to allow the volatile solvent to evaporate. The water bath temperature is between 30℃ and 40℃, and the stirring speed is between 300rpm and 500rpm.

[0102] In the embodiments of this application, a water bath refers to a heating device that uses water as a constant-temperature heat transfer medium. Stirring refers to the operation of causing macroscopic flow and mixing of a liquid through mechanical force.

[0103] It should be noted that the water bath temperature is between 30°C and 40°C. This temperature range is higher than room temperature, which can accelerate the evaporation rate of volatile solvents and shorten the preparation cycle. At the same time, this temperature is lower than the boiling point of most volatile solvents (such as dichloromethane, which has a boiling point of about 39.6°C), ensuring that evaporation takes place in a gentle evaporation manner rather than violent boiling, thereby avoiding damage to the shell structure or the formation of porous defects due to violent vaporization.

[0104] The stirring speed is between 300 rpm and 500 rpm, which is considered slow to medium speed. Its function is to maintain the uniform dispersion of the emulsion without generating strong shear forces. A speed of 300 rpm to 500 rpm can effectively prevent droplet sedimentation and collision agglomeration, while avoiding the generation of eddies or bubbles due to excessive speed, thus ensuring a smooth evaporation process.

[0105] In one possible embodiment, the correspondence between the process parameters of the above-mentioned fluid replenishment bladder preparation process and the product performance can be as follows: polymer concentration (5%→20%, corresponding to wall thickness 200nm→1000nm, trigger pressure 1MPa→6MPa); emulsification speed (8000rpm→15000rpm, corresponding to the radius of the fluid replenishment bladder 50μm→5μm).

[0106] Figure 3 This is a schematic cross-sectional view of the diaphragm provided in an embodiment of this application. The diaphragm integrates the fluid replenishment bladder mentioned in the foregoing embodiments. The specific structural features of the fluid replenishment bladder can be found in the detailed explanation and description of the fluid replenishment bladder in the above examples, and will not be repeated here.

[0107] In one possible implementation of this application embodiment, a diaphragm is also provided. Figure 3 This is a schematic diagram of the cross-sectional structure of a diaphragm provided in an embodiment of this application.

[0108] like Figure 3 As shown above, Figure 1 The fluid replenishment bladder is used in the diaphragm, which includes a base membrane and a coating applied to the surface of the base membrane; The coating is dispersed in a replenishment capsule and binder in an aprotic solvent.

[0109] In one possible embodiment, the binder is polyvinylidene fluoride (PVDF); or / and, The mass ratio of the fluid replenishment bladder to the binder in the coating is between 20:80 and 30:70; or / and, The aprotic solvent is N-methylpyrrolidone (NMP).

[0110] The mass ratio of the fluid filling bladder to the adhesive is between 20:80 and 30:70, for example: 25:80, 30:80, 25:70, etc.

[0111] In one example, the application of the fluid replenishment capsule can be achieved by mixing the prepared biodegradable polymer shell microcapsules (i.e., fluid replenishment capsules) with polyvinylidene fluoride binder at a mass ratio of 20:80–30:70, dispersing them in N-methylpyrrolidone (NMP) to form a uniform slurry, uniformly coating the slurry onto the surface of a commercial PE / PP separator using a slot coating process, with a coating amount of 1–5 g / m², and then vacuum drying at 80°C for 2 h to form a functional composite separator. This can be directly used for the assembly of standard button cells, pouch cells, or cylindrical cells, and is fully compatible with existing battery manufacturing processes without special modifications.

[0112] This application also provides a battery, including the fluid replenishment bladder shown in the example of this application, or the diaphragm shown in the example of this application.

[0113] The specific structural features of the fluid replenishment bladder and the diaphragm can be found in the detailed explanations and descriptions of the fluid replenishment bladder and diaphragm in the examples above, and will not be repeated here.

[0114] This application also provides a device including the battery shown in the example of this application.

[0115] In conjunction with the above embodiments, this application can achieve the following technical effects: 1. The electrolyte replenishment bladder, its preparation method, application, battery, and device provided in this application have a rupture pressure threshold that can be reduced under the influence of temperature or chemical environment during the later stages of battery cycling. This allows the bladder to rupture and release liquid substances even when the internal pressure of the battery has not increased, due to temperature or electrochemical environment changes caused by battery cycling. This effectively replenishes the electrolyte or additives consumed during battery cycling. Therefore, this application can avoid the side reactions and increased internal resistance exacerbated by excessive electrolyte, slow down the rate of battery capacity decay, and extend the battery's cycle life.

[0116] 2. This application initiates coordinated liquid replenishment as soon as the battery degradation signal (temperature rise, voltage abnormality) appears. Compared with single pressure triggering, the timing of liquid replenishment can be advanced, more accurately covering the critical window period when "additives have just been exhausted and electrode expansion stress is still accumulating". This effectively alleviates the capacity decay caused by continuous thickening of the SEI film and interface drying, thereby significantly extending the cycle life of the battery under the same initial liquid injection conditions.

[0117] 3. The fluid replenishment capsule preparation process of this application is mature due to the emulsification-solvent evaporation method, the wide availability and low cost of raw materials (PLA / PMMA, DCM, PVA), and the fact that the preparation cost can be reduced compared to inorganic capsule shell solutions. The equipment is highly versatile and has economic feasibility for direct conversion to existing microcapsule industrial production lines, laying the foundation for the large-scale industrial application of intelligent fluid replenishment membrane technology.

[0118] 4. The liquid replenishment bladder of this application, after the PLA bladder shell is triggered to rupture, can be gradually degraded into small molecules such as lactic acid through hydrolysis in the battery microenvironment, which greatly reduces the risk of long-term physical blockage of lithium ions migrating in the micropores of the separator, and is beneficial to maintaining the ion transport performance of the separator throughout the entire life cycle of the battery.

[0119] 5. The pressure-environment synergy mechanism of this application enables the replenishment bladder to respond to a combination of decay signals such as mechanical pressure, temperature, and electrochemical potential. Compared with a single pressure triggering scheme, it effectively broadens the applicable operating conditions of intelligent replenishment technology. It is particularly suitable for low-rate long-life application scenarios (mainly chemical decay) and batteries under high-temperature conditions (above 45°C), together forming a complete multi-scenario intelligent replenishment solution system.

[0120] In summary, the fluid resuscitation bag shown in the embodiments of this application can be used in the following application scenarios: (1) Cost-sensitive consumer electronics batteries (mobile phones / tablets / laptops): Consumer electronics batteries are highly sensitive to manufacturing costs and have a huge annual production scale. The emulsification-solvent evaporation process is mature and the preparation cost is 50%-70% lower than that of inorganic encapsulation solutions. It can be directly connected to existing polymer microcapsule industrial production lines to achieve large-scale, low-cost mass production.

[0121] (2) Low-rate, long-life energy storage system dominated by chemical decay: In applications such as home energy storage and backup power for communication base stations, the battery operates at a low rate (0.1-0.5C) and mechanical pressure accumulates slowly. However, the depletion of additives and excessive SEI thickness often reach the threshold value before the electrode expansion pressure. The pressure-temperature-electrochemical synergistic triggering mechanism of this application can respond to the chemical decay signal before the mechanical pressure triggers it alone, thus advancing the timing of liquid replenishment.

[0122] (3) High-temperature environment application (above 45°C): Outdoor energy storage, fast charging piles in high-temperature areas, and batteries used in factory workshops operate at 45-60°C for a long time under summer / high-temperature conditions. This application utilizes the inherent characteristic of the elastic modulus of PLA / PMMA softening at high temperatures, so that the trigger threshold value decreases in tandem with the temperature rise, and the electrolyte replenishment can be triggered in the middle of the cycle when heat accumulation is obvious.

[0123] (4) Green and sustainable batteries and circular economy scenarios: For products that meet green standards, after the PLA shell breaks, it gradually hydrolyzes into biodegradable products such as lactic acid in the battery microenvironment, which reduces the risk of long-term physical blockage of the membrane micropores and makes the battery more user-friendly when it is retired and recycled.

[0124] In some examples, embodiments of this application may include, but are not limited to, the following embodiments: Example 1: A fluid replenishment bag, comprising: a bag shell, the bag shell having a receiving cavity, the receiving cavity being encapsulated with a liquid substance, the liquid substance containing the same or partially the same components as the electrolyte; The capsule is designed to rupture when the pressure on the fluid replenishment capsule is not less than the rupture pressure threshold, so that the liquid material inside the capsule can flow out of the capsule. The rupture pressure threshold is reduced by changes in the environment in which the fluid replenishment capsule is located, including at least changes in temperature and / or chemical environment.

[0125] Example 2: The initial value of the rupture pressure threshold is between 1 MPa and 6 MPa, wherein the initial value of the rupture pressure threshold is determined by the material of the bladder shell, the radius of the fluid replenishment bladder, and the thickness of the bladder shell.

[0126] Example 3: The capsule shell of the fluid replenishment bag is made of a biodegradable polymer material, which causes the capsule shell to degrade over time after rupture.

[0127] Example 4: The elastic modulus of the capsule decreases with increasing temperature, resulting in a lower rupture pressure threshold at higher temperatures; and / or, The hydrolysis rate of the capsule is accelerated in an acidic environment, which means that the higher the concentration of acidic substances in the environment, the lower the rupture pressure threshold.

[0128] Example 5: The biodegradable polymeric material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate.

[0129] Example 6: The liquid substance contains at least one of the following additives: fluoroethylene carbonate (FEC), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB).

[0130] Example 7: The thickness of the capsule shell is 200 nm to 1000 nm; or / and, The average radius of the infusion bag is 5 μm to 50 μm; The thickness of the capsule shell and the average radius of the fluid replenishment capsule are determined by the process parameters of the fluid replenishment capsule preparation process. The process parameters include at least one of the following: emulsification speed, polymer concentration, and solvent evaporation rate.

[0131] It should be noted that the fluid resuscitation bag involved in the above embodiments may include at least one of Embodiments 1 to 7. For example, Embodiment 1 may be implemented as an independent embodiment, Embodiment 1+2 may be implemented as an independent embodiment, Embodiment 1+3 may be implemented as an independent embodiment, Embodiment 1+4 may be implemented as an independent embodiment, Embodiment 1+2+4 may be implemented as an independent embodiment, Embodiment 1+3+4 may be implemented as an independent embodiment, Embodiment 1+4+5 may be implemented as an independent embodiment, Embodiment 1+2+4+5 may be implemented as an independent embodiment, Embodiment 1+3+4+5 may be implemented as an independent embodiment, etc., and is not limited to these, and will not be listed one by one here.

[0132] Example 8: A method for preparing a fluid replenishment bag, wherein the fluid replenishment bag is any one of the fluid replenishment bags in Examples 1 to 7 above, and the preparation method includes: Preparation of capsules containing liquid substances; The capsule shell is dried to obtain the fluid replenishment capsule.

[0133] Example 9: The capsule shell is made of a biodegradable polymer material, and the mechanical properties of the biodegradable polymer material decrease under heating or electrochemical action; The fluid replenishment bladder is designed such that when the pressure it withstands reaches the rupture pressure threshold, the bladder shell ruptures and releases liquid substances. The rupture pressure threshold decreases as the mechanical properties of the degradable polymer material decrease.

[0134] Example 10: Preparation of a capsule containing a liquid substance includes: Degradable polymeric materials are dissolved in volatile solvents to obtain polymer oil phase solutions; A composite emulsion is obtained by mixing a polymer oil phase solution with a liquid substance and then emulsifying the mixture. The volatile solvents in the complex emulsion are evaporated to obtain a capsule containing liquid substances.

[0135] Example 11: The biodegradable polymer material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate; In polylactic acid-polymethyl methacrylate copolymers, the ratio of polylactic acid to polymethyl methacrylate is between 3:7 and 7:3.

[0136] Example 12: The volatile solvent is dichloromethane (DCM); or / and, The mass fraction of the polymer oil phase solution ranges from 5% to 20% w / v; the higher the mass fraction of the polymer oil phase solution, the thicker the capsule shell.

[0137] Example 13: A polymer oil phase solution was mixed with a liquid substance and then emulsified to obtain a composite emulsion comprising: Using an aqueous solution containing emulsifier as the continuous phase, a polymer oil phase solution is mixed with a liquid substance and then subjected to high-speed shear emulsification to obtain a composite emulsion.

[0138] Example 14: The emulsifier is polyvinyl alcohol (PVA), and the mass fraction of the emulsifier is between 1% and 2%; or / and, When the polymer oil phase solution is mixed with the liquid substance, the volume ratio of the polymer oil phase solution to the liquid substance is between 3:1 and 5:1; or / and, The rotation speed of high-speed shear emulsification is between 8000 rpm and 15000 rpm. The faster the rotation speed of high-speed shear emulsification, the smaller the radius of the replenishment bladder.

[0139] Example 15: Volatilizing the volatile solvent in the complex emulsion to obtain a capsule containing liquid substances, comprising: The volatile solvents in the volatile composite emulsion cause the biodegradable polymer material to be deposited and precipitated on the surface of the liquid substance, resulting in a capsule containing the liquid substance.

[0140] Example 16: The volatile solvents in the volatile complex emulsion include: The composite emulsion is stirred in a water bath to allow the volatile solvents to evaporate; The water bath temperature is between 30°C and 40°C, and the stirring speed is between 300 rpm and 500 rpm.

[0141] It should be noted that the preparation method of the fluid replenishment bag involved in the above embodiments may include at least one of Embodiments 8 to 16. For example, Embodiment 8 may be implemented as an independent embodiment, Embodiments 8+9 may be implemented as independent embodiments, Embodiments 8+9+10 may be implemented as independent embodiments, Embodiments 8+11 may be implemented as independent embodiments, Embodiments 8+9+11 may be implemented as independent embodiments, Embodiments 8+9+10+11 may be implemented as independent embodiments, etc., and are not limited thereto, and will not be listed in detail here.

[0142] Example 17: A diaphragm, wherein the fluid replenishment bladder of any one of Examples 1 to 7 above is applied to the diaphragm, the diaphragm comprising a base membrane and a coating applied to the surface of the base membrane; The coating comprises a replenishment capsule and a binder dispersed in an aprotic solvent.

[0143] Example 18: The adhesive is polyvinylidene fluoride (PVDF); or / and, The mass ratio of the fluid replenishment bladder to the binder in the coating is between 20:80 and 30:70; or / and, The aprotic solvent is N-methylpyrrolidone (NMP).

[0144] It should be noted that the diaphragm involved in the above embodiments may include at least one of Embodiments 17 to 18. For example, Embodiment 17 may be implemented as a standalone embodiment, and Embodiments 17+18 may be implemented as standalone embodiments.

[0145] Example 19: A battery comprising a fluid replenishment bladder of any one of Examples 1 to 7, or a separator of any one of Examples 17 to 18.

[0146] Example 20: A device including the battery of Example 19, wherein the device includes, but is not limited to, a vehicle, a robot, a personal smart terminal, etc.

[0147] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

[0148] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0149] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A fluid resuscitation bag, characterized in that, include: The capsule has a cavity inside, which encapsulates a liquid substance containing the same or partially the same components as the electrolyte. The shell is designed to rupture when the pressure on the fluid replenishment bladder is not less than a rupture pressure threshold, so that the liquid substance in the containment cavity can flow out of the shell. The rupture pressure threshold decreases under the influence of changes in the environment in which the fluid replenishment bladder is located.

2. The fluid replacement bag according to claim 1, characterized in that, The initial value of the rupture pressure threshold is between 1 MPa and 6 MPa, wherein the initial value of the rupture pressure threshold is determined by the material of the bladder shell, the radius of the fluid replenishment bladder, and the thickness of the bladder shell.

3. The fluid resuscitation bag according to claim 1 or 2, characterized in that, The capsule shell is made of a biodegradable polymer material, which causes the capsule shell to degrade over time after rupture.

4. The fluid resuscitation bag according to claim 2 or 3, characterized in that, The effects of environmental changes include at least the effects of changes in temperature and / or chemical environment; Wherein, the elastic modulus of the shell decreases under increasing temperature, resulting in a lower rupture pressure threshold as the temperature rises; and / or, The hydrolysis rate of the capsule is accelerated under the action of an acidic environment, so that the higher the concentration of acidic substances in the environment, the lower the rupture pressure threshold.

5. The fluid replacement bag according to claim 3, characterized in that, The biodegradable polymeric material includes at least one of the following: polylactic acid (PLA), polymethyl methacrylate (PMMA), and a copolymer of polylactic acid and polymethyl methacrylate. In the polylactic acid-polymethyl methacrylate copolymer, the ratio of polylactic acid to polymethyl methacrylate is between 3:7 and 7:

3.

6. The rehydration bag according to any one of claims 1-5, characterized in that, The liquid substance contains at least one of the following additives: fluoroethylene carbonate (FEC), vinylene carbonate (VC), and lithium difluorooxalate borate (LiDFOB).

7. The rehydration bag according to any one of claims 1-6, characterized in that, The thickness of the capsule shell is 200 nm to 1000 nm; or / and, The average radius of the fluid replenishment bladder is 5 μm to 50 μm.

8. A method for preparing a fluid replenishment bag, characterized in that, The fluid resuscitation bag is the fluid resuscitation bag according to any one of claims 1-7, and the preparation method includes: Preparation of capsules containing liquid substances; The capsule shell is dried to obtain the fluid replenishment capsule.

9. The method according to claim 8, characterized in that, The shell is made of a biodegradable polymer material, the mechanical properties of which decrease under heating or electrochemical action; The fluid replenishment bladder is designed such that when the pressure on the fluid replenishment bladder reaches a rupture pressure threshold, the bladder shell ruptures and releases the liquid substance, and the rupture pressure threshold decreases as the mechanical properties of the degradable polymer material decrease.

10. The method according to claim 8, characterized in that, The preparation of the capsule containing the liquid substance includes: Degradable polymeric materials are dissolved in volatile solvents to obtain polymer oil phase solutions; The polymer oil phase solution is mixed with the liquid substance and then emulsified to obtain a composite emulsion; The volatile solvent in the composite emulsion is evaporated to obtain a capsule containing the liquid substance.

11. The method according to claim 10, characterized in that, The volatile solvent is dichloromethane (DCM); or / and, The polymer oil phase solution has a mass fraction of 5% to 20% w / v; wherein, the higher the mass fraction of the polymer oil phase solution, the thicker the shell.

12. The method according to claim 10, characterized in that, The composite emulsion is obtained by mixing the polymer oil phase solution with the liquid substance and then subjecting it to high-speed shear emulsification, using an aqueous solution containing an emulsifier as the continuous phase. The emulsifier is polyvinyl alcohol (PVA), and the mass fraction of the emulsifier is between 1% and 2%; or / and, After mixing the polymer oil phase solution with the liquid substance, the volume ratio of the polymer oil phase solution to the liquid substance is between 3:1 and 5:1; or / and, The high-speed shear emulsification rotation speed is between 8000 rpm and 15000 rpm. The faster the high-speed shear emulsification rotation speed, the smaller the radius of the fluid replenishment bladder.

13. The method according to claim 10, characterized in that, The volatile solvents in the composite emulsion that are evaporated include: The composite emulsion is stirred in a water bath to allow the volatile solvent to evaporate. The water bath temperature is between 30°C and 40°C, and the stirring speed is between 300 rpm and 500 rpm.

14. A diaphragm, characterized in that, The fluid replenishment capsule as described in any one of claims 1-7 is applied to the diaphragm, the diaphragm comprising a base membrane and a coating applied to the surface of the base membrane; The coating comprises the fluid filling bladder and an adhesive.

15. The diaphragm according to claim 14, characterized in that, The adhesive is polyvinylidene fluoride (PVDF); or / and, The mass ratio of the fluid replenishment bladder to the adhesive in the coating is between 20:80 and 30:70; or / and, The aprotic solvent is N-methylpyrrolidone (NMP).

16. A battery, characterized in that, The battery includes a fluid replenishment bladder as described in any one of claims 1-7 or a separator as described in any one of claims 14-15.

17. A device, characterized in that, The device includes the battery as described in claim 16.

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