Self-sealing electrolyte cells, batteries, and self-sealing electrolyte control methods

Abstract

This invention relates to the field of lithium-ion pouch batteries, specifically to a self-replenishing battery cell, a battery, and a self-replenishing control method. The self-replenishing battery cell is equipped with a preheating electrolyte-releasing replenishment component, and an adapted replenishment control method enables automatic electrolyte replenishment. The self-replenishing battery cell structure provided in this application is suitable for cells of different capacities and can significantly extend battery cycle performance. The replenishment method can melt the sealed capsule as needed to achieve automatic electrolyte replenishment. Furthermore, the heat generation of the battery cell is controlled during the self-replenishment process, without opening the casing, drilling holes, or disassembling the seal, achieving effective and safe automatic replenishment with great application potential.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion pouch batteries, and more specifically, to self-replenishing cells, batteries, and self-replenishing control methods. Background Technology

[0002] In the field of battery technology, replenishable electrolyte batteries, as a type of battery that can extend lifespan and improve cycle performance, are widely used in power tools, energy storage systems, and portable devices. Early replenishable electrolyte batteries typically used an open structure, maintaining cell performance by manually adding electrolyte periodically. However, this type of battery suffers from problems such as electrolyte evaporation, leakage, and high maintenance costs.

[0003] With technological advancements, most existing replenishable batteries employ a combination of external replenishment tubes, sealing plugs, and threaded sealing caps. A typical approach involves creating a separate replenishment hole on the battery casing, and replenishment is achieved through steps such as injecting electrolyte, inserting the sealing plug, and tightening the sealing cap. However, this structure has significant technical limitations. First, the external design of the replenishment channel and sealing components leads to a complex overall structure with numerous parts, increasing manufacturing difficulty and cost. Second, the sealing reliability is low; external seals are prone to failure during long-term use due to thermal expansion and contraction, mechanical vibration, or aging of the sealing material, causing electrolyte leakage or the entry of external gases, thus affecting battery safety and cycle life. More critically, current technologies require multiple steps in production and replenishment, including injecting electrolyte, inserting the sealing plug, tightening the sealing cap, settling, opening the cap for formation, re-opening and removing the plug for replenishment, and resealing. This cumbersome operation is highly dependent on manual labor or external equipment. This repeated opening and unsealing process easily introduces air impurities or moisture during replenishment, increasing the risk of internal contamination and leakage, and is difficult to automate for mass production. Furthermore, due to the presence of the electrolyte filling hole and sealing components, the battery cell cannot achieve a truly fully sealed state, and it is impossible to realize the automatic electrolyte filling function without openings or unsealing in the finished battery cell. This has become a major bottleneck restricting the development of battery integration and maintenance-free operation.

[0004] Therefore, how to provide a self-filling liquid structure for soft-pack cells that can overcome the above defects and achieve full sealing, no external liquid filling hole, no sealing plug or sealing cap has become a technical problem that urgently needs to be solved in the current battery field. Summary of the Invention

[0005] The purpose of this invention is to provide a self-filling battery cell, a battery, and its preparation method and application. The self-filling battery cell has a fully sealed, soft-pack self-filling structure without external filling holes, sealing plugs, or sealing caps.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a self-sealing electrolyte battery cell, comprising a battery cell body, an aluminum-plastic film, a positive electrode tab, and a negative electrode tab. A top sealing area is provided at the junction of the aluminum-plastic film and the positive and negative electrode tabs. The positive electrode tab includes a positive electrode sheet tab and an external metal tab, and the negative electrode tab includes a negative electrode sheet tab and an external metal tab. The positive electrode sheet tab, the negative electrode sheet tab, and the external metal tab are welded together through a welding area. Includes a liquid replenishment component located in the top sealing area, which is fixedly positioned between the aluminum-plastic film and the positive electrode tab and / or the negative electrode tab; The electrolyte replenishment assembly and the main body of the battery cell are located in the same sealed cavity; The fluid replenishment assembly includes a sealed capsule and an electrolyte replenishment solution disposed within the sealed capsule; The current-carrying capacity of the positive electrode tab and negative electrode tab > the current-carrying capacity of the external metal tab > the current-carrying capacity of the welding area; The sealed capsule abuts against the welding area.

[0007] In an optional embodiment, the sealed capsule is configured as a meltable capsule bag, the meltable capsule bag having a melting temperature of 95~115°C; Optionally, the material of the meltable capsule bag includes one or more of PE, PP, EVA, and TPU.

[0008] In an optional embodiment, the wall thickness of the meltable capsule bag on the side closer to the welding area is less than the wall thickness on the side farther from the welding area.

[0009] In an optional implementation, the mass of electrolyte replenishment is 3% to 20% of the initial electrolyte volume injected into the cell body.

[0010] In a second aspect, the present invention provides a self-replenishing battery, comprising the self-replenishing cell of claim 1 and a replenishment control system.

[0011] Thirdly, the present invention provides a self-replenishing fluid control method, comprising the following steps: S1: The battery cell is controlled to discharge at a current of 20C~30C through the liquid replenishment control system, so that the temperature of the welding area rises to 80℃~90℃; S2: The electrolyte replenishment control system controls the cell to discharge at a current of 40C~60C, and the welding area is heated to 105℃~110℃, causing the sealed capsule to melt and the electrolyte replenishment to flow into the cell, thus completing the electrolyte replenishment.

[0012] In an optional embodiment, after the electrolyte replenishment flows into the cell, the process further includes: S3: The battery cell is controlled to discharge at a current of 12C~18C through the liquid replenishment control system, so that the internal temperature of the battery cell is maintained at ≥95℃; Optionally, it also includes: S4: The cell discharge is cut off by the liquid replenishment control system, and then the cell capacity and internal resistance are retested by the liquid replenishment control system.

[0013] In optional implementations, in S1 and S2, the discharge includes one or more of the following methods: (1) Constant current discharge; (2) Constant power discharge; (3) Pulse discharge; (4) Intermittent discharge.

[0014] In an optional implementation, the cell voltage, DC internal resistance, temperature, number of cycles, and high-temperature, high-rate service time are collected by the liquid replenishment control system, and the real-time capacity and health status of the cell are calculated. Cell health status = Cactual / Cinitial × 100%, where Cinitial is the initial capacity of the battery and Cactual is the real-time capacity of the battery.

[0015] In an optional implementation, self-replenishment is performed when the following conditions are met simultaneously: (1) The cell health status drops below 90%; (2) The DC internal resistance of the self-replenishing battery cell increases by 15% to 25% compared to the initial DC internal resistance value of the cell; (3) The self-replenishing electrolyte cell is within the safe temperature range of 10℃~45℃ and the voltage is normal; (4) The self-replenishing electrolyte cell is in a static, non-charging, and non-high-power output state.

[0016] The present invention has the following beneficial effects: This application provides a self-replenishing electrolyte cell structure and a corresponding electrolyte replenishment control method. The self-replenishing electrolyte cell structure is suitable for cells of different capacities and can significantly extend the battery cycle performance. The electrolyte replenishment method can melt the sealed capsule as needed to achieve automatic electrolyte replenishment. Furthermore, the cell heat generation is controlled during the self-replenishment process, and the cell does not need to be opened, drilled, or unsealed, thus achieving effective and safe automatic electrolyte replenishment, which has great application prospects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the self-filling electrolyte cell of this application; wherein: 1. Battery cell body; 2. Aluminum-plastic film; 3. Positive electrode tab; 31. Positive electrode sheet tab; 32. External metal tab; 4. Negative electrode tab; 41. Negative electrode sheet tab; 5. Top sealing area; 6. Welding area; 7. Liquid replenishment assembly; 71. Sealing capsule. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] like Figure 1 As shown, the present invention provides a self-replenishing electrolyte cell, including a cell body 1, an aluminum-plastic film 2, a positive electrode tab 3, and a negative electrode tab 4. A top sealing area 5 is provided at the junction of the aluminum-plastic film 2 with the positive electrode tab 3 and the negative electrode tab 4. The positive electrode tab 3 includes a positive electrode sheet tab 31 and an external metal tab 32, and the negative electrode tab 4 includes a negative electrode sheet tab 41 and an external metal tab 32. The positive electrode sheet tab 31, the negative electrode sheet tab 32, and the external metal tab 32 are respectively welded together through a welding area 6. The invention also includes an electrolyte replenishment component 7 disposed in the top sealing area 5. The electrolyte replenishment component 7 is fixedly disposed between the aluminum-plastic film 2 and the positive electrode tab 3 and / or the negative electrode tab 4; the electrolyte replenishment component 7 and the battery cell body 1 are located in the same sealed cavity; the electrolyte replenishment component 7 includes a sealing capsule 71 and an electrolyte replenishment solution disposed inside the sealing capsule; when the sealing capsule 71 is heated, the electrolyte replenishment solution can overflow from the sealing capsule 71; the current carrying capacity of the positive electrode tab 31 and the negative electrode tab 41 is greater than the current carrying capacity of the external metal tab 32, which is greater than the current carrying capacity of the welding area 6; the sealing capsule 71 abuts against the welding area 6.

[0021] In this invention, the electrolyte replenishment component is configured to release electrolyte upon heating, and the sealing capsule in the electrolyte replenishment component is configured to abut against the welding area. By setting the current carrying capacity gradient of the electrode tab, external metal tab, and welding area, the welding area of ​​the self-replenishing battery cell has the highest temperature rise when current passes through it, which heats the sealing capsule and releases the electrolyte replenishment into the battery cell body, ultimately achieving fully sealed automatic electrolyte replenishment.

[0022] In an optional embodiment, the sealed capsule is configured as a meltable capsule bag, and the meltable capsule bag has a melting temperature of 95~115℃.

[0023] Optionally, the melting temperature of the meltable capsule bag is 95~105℃.

[0024] In an optional embodiment, the material of the meltable capsule bag includes one or more of PE, PP, EVA, and TPU.

[0025] Optionally, the meltable capsule bag is a PE / PP / EVA copolymer.

[0026] In this invention, a polymer with a melting temperature of 95~115℃ is selected as the material for the fusible capsule bag. Combined with the aforementioned current capacity gradient setting, the self-replenishing battery cell experiences the highest temperature rise at the welding area during high-current charging and discharging. Once the temperature reaches the melting temperature of the fusible capsule bag, the fusible capsule bag, which is in contact with the welding area, melts upon heating, thereby releasing electrolyte into the self-replenishing battery cell. During this period, the temperature of the battery cell body is below 90℃, which will not affect the battery cell body. Furthermore, the polymer material used in the fusible capsule bag remains stable inside the battery cell and does not react with the substances inside the battery. Moreover, since the fusible capsule bag and the battery cell body are located in the same sealed cavity, the melting of the capsule bag will not affect the overall sealing performance of the self-replenishing battery cell.

[0027] In an optional embodiment, the mass of the electrolyte replenishment is 3% to 20% of the initial electrolyte volume of the battery cell. If it is less than 3%, the battery cell cannot be completely wetted, and if it is more than 20%, the amount of gas generated inside the battery cell will increase.

[0028] In an optional embodiment, the capacity of the battery cell body is 5 Ah to 100 Ah.

[0029] Optionally, the battery cell body has a height of 120–280 mm, a width of 120–280 mm, and a thickness of 5–20 mm.

[0030] In an optional embodiment, the meltable capsule bag has a length of 100-300 mm, a width of 5-15 mm, and a thickness of 5-15 mm.

[0031] In this invention, a sealing capsule is disposed in the top sealing area. From a dimensional perspective, due to area limitations at the top sealing area and the packaging process, the size of the sealing capsule can be slightly larger than the size of the battery cell body along the length of the top sealing area. In the other two directions, the size of the sealing capsule is limited by the size of the top sealing area, and its thickness cannot exceed the thickness of the battery cell body. From a capacity perspective, the weight of the electrolyte replenishment in the sealing capsule is 3% to 20% of the initial electrolyte filling volume of the battery cell body, and the size of the sealing capsule can be adjusted according to the required amount of electrolyte replenishment. Overall, the overall size of the sealing capsule can be adjusted according to the size and capacity of the self-replenishing battery cell.

[0032] In an optional embodiment, the wall thickness of the meltable capsule bag is 0.03~0.2 mm.

[0033] In an optional embodiment, the wall thickness of the fusible capsule bag on the side closer to the welding area is less than the wall thickness on the side farther from the welding area.

[0034] In an optional embodiment, the wall thickness of the meltable capsule bag on the side near the welding area is 0.03~0.1 mm.

[0035] In an optional embodiment, the wall thickness of the meltable capsule bag on the side away from the welding area is 0.1~0.2 mm.

[0036] In this invention, the wall thickness of the fusible capsule bag on the side closer to the welding area is less than the wall thickness on the side farther from the welding area, so that the fusible capsule bag can be directionally melted at high temperature.

[0037] In an optional embodiment, the welding area includes a first welding area and a second welding area; The positive electrode tab and the external metal tab are connected by welding in the first welding area, and the negative electrode tab and the external metal tab are connected by welding in the second welding area.

[0038] In an optional embodiment, the welding method is ultrasonic welding.

[0039] In an optional embodiment, the sealing capsule abuts against the first welding area and / or the second welding area.

[0040] In this invention, the current-carrying capacity of the positive electrode tab and negative electrode tab is set to be greater than that of the external metal tab, which in turn is greater than that of the welding area. The purpose is to utilize the fact that different areas of the self-replenishing battery cell have different temperatures when a large current is passed through them, so that the welding area has the highest temperature. This causes the fusible capsule to melt and release electrolyte to replenish the battery cell body, thus achieving automatic electrolyte replenishment. In an optional implementation, the above-mentioned overcurrent capacity gradient is achieved as follows: The positive electrode adopts a multi-tab parallel structure of aluminum foil, with a blank width of ≥15 mm for a single current collector and a total current-carrying cross-sectional area of ​​≥25 mm² for multiple foils connected in parallel; the negative electrode adopts a thickened copper foil current collector (8-12 μm) and increases the number of tabs, significantly reducing the substrate tab resistance. The aforementioned blank space for the current collector refers to the area on the battery electrode that is intentionally left uncoated with active material (slurry).

[0041] The cross-sectional area of ​​the external metal tab is moderately reduced, and the cross-sectional area of ​​the external metal tab is controlled to be slightly smaller than the total cross-sectional area of ​​the internal tab: the thickness of the positive electrode aluminum strip is 0.10-0.15 mm and the width is 6-8 mm; the thickness of the negative electrode copper / nickel strip is 0.10-0.15 mm and the width is 6-8 mm, forming a first-stage resistance increase.

[0042] The contact resistance of the welding area is designed to be the highest. Taking ultrasonic welding as an example, by controlling the ultrasonic welding pressure of 0.35-0.55 MPa, amplitude of 25-35 μm, and welding time of 0.2-0.4 s, the area of ​​the welding area is made slightly smaller than the contact area of ​​the electrode tab, thus maintaining a stable contact resistance and ultimately forming a resistance gradient: R(positive electrode tab / negative electrode tab) < R(external metal tab) < R(welding area). This achieves a gradient in the current carrying capacity of different areas, thereby ensuring that the heat generated during discharge is concentrated in the welding area, and thus achieving directional and precise heating of the sealed capsule, releasing electrolyte replenishment into the cell body.

[0043] Secondly, the present invention provides a self-replenishing battery, including the aforementioned self-replenishing cell and a replenishment control system.

[0044] In an optional implementation, the liquid replenishment control system can collect the cell voltage, DC internal resistance (DCR), temperature, cycle number, and high-temperature high-rate service history of the self-replenishing cell and / or self-replenishing battery in real time, and can control the current and voltage of the self-replenishing cell and / or self-replenishing battery.

[0045] Thirdly, the present invention provides a self-liquidation control method for the above-mentioned self-liquidation battery, comprising the following steps: S1: The self-replenishing battery cell is controlled by the liquid replenishment control system to discharge at a current of 20C~30C, so that the temperature of the welding area rises to 80℃~90℃. S2: The self-replenishing battery cell is controlled by the electrolyte replenishment control system to discharge at a current of 40C~60C. The welding area is heated to 105℃~110℃, causing the sealed capsule to melt. The electrolyte replenishment flows into the battery cell body, completing the electrolyte replenishment.

[0046] In this invention, the current carrying capacity of the electrode tab, the external metal tab, and the welding area is set in a gradient. When electrolyte replenishment is required, the electrolyte replenishment control system can control the current through the self-replenishing battery cell, so that the temperature of the welding area rises to a range that can cause the sealing capsule to melt, thereby allowing the electrolyte in the sealing capsule to flow into the battery cell body and complete the automatic electrolyte replenishment.

[0047] In the self-replenishing control method, step S1 is the preheating and temperature equalization stage, which raises the temperature of the welding area to 80℃~90℃, eliminates the temperature difference between the inside and outside of the sealed capsule, and avoids local overheating and damage to the battery. Step S2 is the high-temperature melting stage, which controls the temperature of the welding area to be stable at 105℃~110℃ through real-time closed-loop adjustment of the replenishment control system, counteracts the endothermic effect of the electrolyte, and ensures that the sealed capsule melts and ruptures stably. The melting causes the capsule to break, and the electrolyte replenishment flows into the cell body, completing the automatic replenishment.

[0048] In an optional embodiment, after the electrolyte replenishment flows into the cell, the process further includes: S3: The self-replenishing battery cell is controlled by the liquid replenishment control system to discharge at a current of 12C~18C, so that the internal temperature of the battery cell is maintained at ≥95℃. Optionally, it also includes: S4: The cell discharge is cut off through the liquid replenishment control system.

[0049] In the self-replenishing control method, step S3 is the heat preservation and wetting stage, which prevents the sealed capsule melt port from being resealed by cold, and ensures that the electrolyte replenishment fully wets the diaphragm and electrode under the capillary action of the melt port; step S4 is the end stage, which cuts off the discharge circuit through the replenishment control system, and the self-replenishing cell is naturally heated to room temperature, completing one automatic replenishment. Optionally, the self-replenishing fluid control method also includes: S5: Verify the fluid replenishment effect through the fluid replenishment control system.

[0050] Step S5 in the self-replenishing control method is for effect verification. The cell capacity and internal resistance are automatically retested using the replenishment control system to verify the replenishment effect. The number of replenishment operations is latched (single trigger latch) to prevent repeated replenishment actions and ensure that the replenishment process is controllable and traceable, forming a complete control closed loop with the BMS trigger identification logic mentioned above.

[0051] In optional implementations, in S1, S2, and S3, the discharge includes one or more of the following methods: (1) Constant current discharge; (2) Constant power discharge; (3) Pulse discharge; (4) Intermittent discharge.

[0052] In an optional implementation, the cell voltage, DC internal resistance, temperature, number of cycles, and high-temperature, high-rate service time are collected by the electrolyte replenishment control system, and the real-time capacity and state of health (SOH) of the cell are calculated. Cell health status = Cactual / Cinitial × 100%, where Cinitial is the initial capacity of the battery and Cactual is the real-time capacity of the battery.

[0053] In an optional implementation, self-replenishment is performed when the following conditions are met simultaneously: (1) The cell health status drops below 90%; (2) The DC internal resistance of the self-replenishing battery cell increases by 15% to 25% compared to the initial DC internal resistance value of the cell; (3) The self-replenishing electrolyte cell is within the safe temperature range of 10℃~45℃ and the voltage is normal; (4) The self-replenishing electrolyte cell is in a static, non-charging, and non-high-power output state.

[0054] In an optional implementation, the fluid replenishment control system is a BMS system.

[0055] The BMS system is used to collect parameters such as cell voltage, DC internal resistance, and temperature in self-replenishing cells or batteries in real time. Closed-loop control is carried out according to the process of preheating and temperature equalization and high-temperature melting to accurately match the melting characteristics of the sealed capsule with the electrolyte wetting requirements, so as to achieve fully sealed automatic electrolyte replenishment.

[0056] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0057] Example 1 This embodiment provides a self-replenishing electrolyte cell and a self-replenishing electrolyte battery. The battery cell includes a main body, an aluminum-plastic film, a positive electrode tab, and a negative electrode tab. A top sealing area is provided at the junction of the aluminum-plastic film and the positive and negative electrode tabs. The positive electrode tab includes a positive electrode sheet tab and an external metal tab, and the negative electrode tab includes a negative electrode sheet tab and an external metal tab. The positive and negative electrode sheets tabs are welded to the external metal tab via a welding area. The self-replenishing battery cell has the following specifications: Cell type: 20 Ah capacity soft-pack power cell; Cell size: 14 mm × 150 mm × 145 mm (thickness × width × height); Initial electrolyte filling volume: 130 g. It also includes a replenishing component located in the top sealing area, fixedly positioned between the aluminum-plastic film and the positive and / or negative electrode tabs. The replenishing component and the main body of the battery cell are within the same sealed cavity. The replenishing component includes a sealed capsule and electrolyte replenishment within the sealed capsule. The sealed capsule is a fusible capsule bag with dimensions of 140 mm × 6 mm × 7 mm. mm; electrolyte filling in sealed capsules: 6.5 g; melting temperature of meltable capsule bags: 95~115℃; material of meltable capsule bags: PE / PP / EVA copolymer; Example 2 This embodiment provides a self-replenishing electrolyte cell and a self-replenishing electrolyte battery, which are basically the same as those in Embodiment 1 in terms of setup, except that: Self-filling electrolyte cell: Cell type: 50 Ah high-capacity soft-pack power cell; Cell dimensions: width 220 mm, height 165 mm, thickness 17 mm; Initial electrolyte filling volume: 320 g; Sealed capsule: Capsule dimensions: 210 mm long × 9 mm wide × 9 mm thick; Capsule volume: approximately 17 mL; Compensating electrolyte in capsule: 20 g.

[0058] Example 3 This embodiment provides a self-replenishing electrolyte cell and a self-replenishing electrolyte battery, which are basically the same as those in Embodiment 1 in terms of setup, except that: Self-filling electrolyte cell: Cell type: 100 Ah high-capacity soft-pack power cell; Cell dimensions: Width 280 mm, Height 280 mm, Thickness 20 mm; Initial electrolyte filling volume: 650 g; Sealed capsule: Capsule dimensions: 260 mm long × 12 mm wide × 14 mm thick; Capsule volume: approximately 17 mL; Compensating electrolyte inside the capsule: 50 g.

[0059] Example 4 This embodiment provides a liquid replenishment control method for the 20 Ah self-liquidating cell and self-liquidating battery provided in Embodiment 1. The liquid replenishment control system is a BMS system, including: S0: Use BMS to collect cell voltage, DC internal resistance, temperature, cycle count, and high-temperature, high-rate service time, and calculate the real-time cell capacity and cell health status; Cell health status = Cactual / Cinitial × 100%, where Cinitial is the initial capacity of the battery, and Cactual is the real-time capacity of the battery; The self-replenishing fluid battery status is: (1) The cell health status dropped to 88%; (2) The DC internal resistance of the self-replenishing electrolyte cell increases by 20% compared to the initial DC internal resistance value of the cell; (3) The self-replenishing electrolyte cell is within the safe temperature range of 25℃ and the voltage is normal, at 3.2 V; (4) The self-replenishing electrolyte cell is in a static state; If all triggering conditions are met, administer fluid replacement.

[0060] S1: The BMS controls the self-replenishing electrolyte cell to discharge at a constant current of 25 C for 45 s, raising the temperature of the welding area to 85℃. S2: The BMS controls the self-replenishing battery cell to discharge at a current of 50 C for 60 s. The temperature sensor is used for real-time closed-loop adjustment to control the temperature of the welding area to rise to 108°C, so that the sealing capsule melts and the electrolyte replenishment flows into the battery cell body. S3: The BMS controls the self-replenishing battery cell to discharge at a current of 15 C for 45 s, so that the internal temperature of the battery cell is kept ≥95℃. S4: The BMS cuts off the discharge circuit, and the battery cell naturally cools to room temperature, completing one automatic electrolyte replenishment cycle. S5: The BMS automatically retests the cell capacity and internal resistance, verifies the electrolyte replenishment effect, and latches the number of electrolyte replenishment operations (single-trigger latch).

[0061] The state of the self-replenishing battery before and after replenishment was tested, and the results are shown in Tables 1 and 2.

[0062] Table 1. Results of fluid rehydration status testing before and after in Example 4

[0063] Examples 5 and 6 The self-replenishing batteries prepared in Examples 2 and 3 were replenished with liquid using the same control method as in Example 4.

[0064] The state of the self-replenishing battery after replenishment was tested, and the results are shown in Table 1.

[0065] Comparative Example 1 This comparative example is basically the same as Example 1, except that no liquid replenishment component was set.

[0066] Table 2. Status detection of batteries in Comparative Example 1 and self-liquidating batteries in Examples 4-6 after liquid replenishment.

[0067] As can be seen from Table 2, the self-liquidating cell structure provided in this application can be applied to cells of different capacities. The cells can maintain a sealed state during the self-liquidating process, and the self-liquidating process will not cause the internal separator of the battery to melt and shrink.

[0068] Comparative Example 2 This comparative example is basically the same as Example 4, except that fluid replenishment is performed only when the self-replenishment triggering condition is partially met. Specifically: (1) The cell health status drops to 95%; (2) The DC internal resistance of the self-replenishing battery cell increases by 5% compared to the initial DC internal resistance value of the cell; (3) The self-replenishing electrolyte cell is within the safe temperature range of 25℃ and the voltage is normal, at 3.2 V; (4) The self-replenishing electrolyte cell is in a static state.

[0069] The state of the self-replenishing battery before and after replenishment was tested, and the results are shown in Table 3.

[0070] Table 3. Results of state testing of self-liquid-replenishing batteries before and after liquid replenishment in Comparative Example 2

[0071] As can be seen from Tables 1 and 3, if only some of the triggering conditions are met, the battery will become soft due to excessive internal electrolyte, increasing the risk of gas production. However, the self-replenishing electrolyte structure and control method of the present invention can achieve safe and effective electrolyte replenishment and significantly restore the cell performance.

Claims

1. A self-sealing electrolyte battery cell, comprising a cell body, an aluminum-plastic film, a positive electrode tab, and a negative electrode tab, wherein a top sealing area is provided at the junction of the aluminum-plastic film and the positive and negative electrode tabs, the positive electrode tab includes a positive electrode sheet tab and an external metal tab, the negative electrode tab includes a negative electrode sheet tab and an external metal tab, and the positive electrode sheet tab, negative electrode sheet tab, and external metal tab are welded together through a welding area, characterized in that... It includes a liquid replenishment component disposed in the top sealing area, wherein the liquid replenishment component is fixedly disposed between the aluminum-plastic film and the positive electrode tab and / or the negative electrode tab; The liquid replenishment component and the main body of the battery cell are located in the same sealed cavity; The fluid replenishment assembly includes a sealed capsule and an electrolyte replenishment solution disposed inside the sealed capsule; The current-carrying capacity of the positive electrode tab and the negative electrode tab is greater than the current-carrying capacity of the external metal tab, which is greater than the current-carrying capacity of the welding area. The sealing capsule abuts against the welding area.

2. The self-replenishing electrolyte cell according to claim 1, wherein the sealing capsule is configured as a fusible capsule bag, and the melting temperature of the fusible capsule bag is 95~115℃; Optionally, the material of the meltable capsule bag includes one or more of PE, PP, EVA, and TPU.

3. The self-sealing electrolyte cell according to claim 2, wherein the wall thickness of the fusible capsule bag on the side near the welding area is less than the wall thickness on the side away from the welding area.

4. The self-replenishing electrolyte cell according to claim 1, wherein the mass of the electrolyte replenishment is 3% to 20% of the initial electrolyte volume of the cell body.

5. A self-replenishing battery, comprising the self-replenishing cell as described in claim 1 and a replenishment control system.

6. The self-liquidation control method for a self-liquidation battery as described in claim 5, comprising the following steps: S1: The battery cell is controlled to discharge at a current of 20C~30C through the liquid replenishment control system, so that the temperature of the welding area rises to 80℃~90℃; S2: The electrolyte replenishment control system controls the cell to discharge at a current of 40C~60C, and the welding area is heated to 105℃~110℃, causing the sealed capsule to melt and the electrolyte replenishment to flow into the cell, thus completing the electrolyte replenishment.

7. The self-replenishing electrolyte control method according to claim 6, further comprising, after the electrolyte replenishment flows into the cell, the method further includes: S3: The battery cell is controlled to discharge at a current of 12C~18C through the liquid replenishment control system, so that the internal temperature of the battery cell is maintained at ≥95℃; Optionally, it also includes: S4: The cell discharge is cut off by the liquid replenishment control system, and then the cell capacity and internal resistance are retested by the liquid replenishment control system.

8. The self-replenishing fluid control method according to claim 6, wherein in S1 and S2, the discharge includes one or more of the following methods: (1) Constant current discharge; (2) Constant power discharge; (3) Pulse discharge; (4) Intermittent discharge.

9. The self-replenishing fluid control method according to claim 6, The electrolyte replenishment control system collects cell voltage, DC internal resistance, temperature, cycle count, and high-temperature, high-rate service time, and calculates the real-time capacity and health status of the cells. The cell health status is calculated as Cactual / Cinitial × 100%, where Cinitial is the initial capacity of the battery and Cactual is the real-time capacity of the battery.

10. The self-replenishing fluid control method according to claim 6 or 9, wherein self-replenishing fluid is performed when the following conditions are met simultaneously: (1) The cell health status drops below 90%; The cell health status = Cactual / Cinitial × 100%, where Cinitial is the initial capacity of the battery and Cactual is the real-time capacity of the battery. (2) The DC internal resistance of the self-replenishing battery cell increases by 15% to 25% compared to the initial DC internal resistance value of the cell; (3) The self-replenishing electrolyte cell is within the safe temperature range of 10℃~45℃ and the voltage is normal; (4) The self-replenishing electrolyte cell is in a static, non-charging, and non-high-power output state.

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