Square battery cover plate with adaptive explosion-proof valve and secondary liquid supplement bin and square battery

Abstract

The application discloses a square battery cover plate with an adaptive explosion-proof valve and a secondary liquid supplement bin and a square battery. The square battery cover plate comprises an explosion-proof valve, wherein the explosion-proof valve comprises a sensor structure arranged in a circular exhaust bin of the battery cover plate and a one-way air pressure adjusting device arranged around the top outer side of the sensor structure; the sensor structure comprises sensors for detecting the gas composition, pressure and temperature inside the battery, and the three sensor axis lines are connected in a triangular shape and are connected through at least two vertically-separated connecting plates; a high-enthalpy solid-solid phase change material in the form of a circular peak heat flow reduction is embedded in the thermal protection material of the lower connecting plate made of a porous thermal protection material with low thermal conductivity, ablation resistance and impact resistance, so as to form a distributed metal dot array; the bottom of the battery cover plate is provided with a secondary liquid supplement bin for storing electrolyte, and the stored electrolyte is automatically supplemented into the battery. The application can intelligently detect the changes of the gas composition, pressure and temperature inside the battery, realize intelligent pressure relief and explosion prevention, and automatically supplement liquid.

Description

Technical Field

[0001] This invention relates to the field of square battery technology, and in particular to a square battery cover plate and a square battery having an adaptive explosion-proof valve and a secondary liquid replenishment tank. Background Technology

[0002] There are three main types of lithium battery packaging: cylindrical, pouch, and prismatic. According to a research report released by Guolian Securities, prismatic batteries account for over 90% of the domestic power and energy storage market. The structural safety design of these batteries is crucial. Prismatic batteries generally consist of a battery cover and a battery casing. The design of the battery cover is particularly important. The battery cover comprises four main parts: a top cover plate, positive and negative terminals, an explosion-proof device, and an injection hole. When a battery experiences thermal runaway, the internal temperature and pressure increase. When the pressure exceeds the withstand pressure of the explosion-proof valve, the passive gas pressure explosion-proof valve of the battery cover opens, releasing gas or spraying flames, or even igniting and exploding with the outside air. During thermal runaway, the internal temperature of the battery can reach over 900°C, causing the plastic of the battery casing and battery cover to melt, resulting in heat spread. The lack of early warning regarding the temperature and gas levels inside the battery casing means that the safety hazards of prismatic batteries persist.

[0003] Chinese invention patent CN117977117A discloses a square battery with a stopper between the battery cover and the electrode assembly. When the battery experiences thermal runaway, the stopper supports the electrode assembly. The stopper has a high-strength, high-pore structure to ensure airflow to the pressure relief mechanism. The main innovation of this invention patent is the stopper, which isolates the thermal runaway electrode assembly from the thermal runaway degree of the battery cover to a certain extent. However, it cannot reduce the battery's safety hazards. In addition, the energy of heat and gas generation in the battery cannot be reduced. Can the battery's safety be fundamentally solved through design?

[0004] Chinese invention patent CN201478351U relates to a first electrode and a second electrode of a square battery cover. The second electrode includes a top cover, a bottom plate, and a safety film. The safety film is located on the bottom plate, with its center recessed downwards and connected to the bottom plate. It can achieve pressure relief and power cut-off to prevent the battery from exploding and endangering personal safety. This invention adopts a passive pressure relief method, which cannot provide early warning and handling of battery safety hazards. It can only reduce the severity of battery safety disasters to a certain extent, but cannot actively control the situation or reduce the frequency of accidents. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and defects of the prior art and provide a square battery cover and a square battery with an adaptive explosion-proof valve and a secondary liquid replenishment tank. The square battery cover integrates an intelligent sensor for monitoring the gas, temperature and pressure inside the square battery, and is equipped with a one-way air pressure regulating device, a distributed metal array for rapid cooling turbulence, and a secondary liquid replenishment tank. It aims to solve the problems of excessive free electrolyte in existing square batteries, which affects the battery's electrical and safety performance, or the safety hazards caused by the passive valve opening in the event of battery thermal runaway.

[0006] One objective of this invention is to provide a square battery cover with an adaptive explosion-proof valve and a secondary electrolyte replenishment chamber. The cover includes an explosion-proof valve comprising a sensor structure arranged within a circular venting chamber of the battery cover and a one-way pressure regulating device arranged around the top outer side of the sensor structure. The sensor structure is connected and fixed to the inner wall of the venting chamber via a triangular plate inscribed in the circle. The sensor structure includes three sensors for detecting the gas composition, pressure, and temperature inside the battery. The axes of the three sensors form a triangle and are connected by at least two vertically spaced connecting plates to form a stable structure. The lower connecting plate, made of a porous thermal protection material with low thermal conductivity, ablation resistance, and impact resistance, incorporates a circular high-enthalpy solid-solid phase change material to achieve peak heat flux reduction, forming a distributed metal lattice. A secondary electrolyte replenishment chamber is located at the bottom of the battery cover for automatically replenishing electrolyte into the battery during use.

[0007] Preferably, the outlet at the bottom of the secondary electrolyte replenishment chamber is sealed with pressure-sensitive sealant. During battery use, as the internal pressure of the battery increases, the pressure-sensitive sealant fails, allowing the electrolyte inside to be automatically replenished from the secondary electrolyte replenishment chamber into the battery.

[0008] The pressure-sensitive sealant has a pressure resistance of 0-0.6 MPa; if the pressure exceeds 0.6 MPa, the pressure-sensitive sealant will fail.

[0009] The pressure-sensitive sealant is made of a zinc oxide-polytetrafluoroethylene mixture or an acrylic pressure-sensitive adhesive.

[0010] There is a secondary liquid replenishment chamber under the positive and negative terminal plates of the battery cover, and the two secondary liquid replenishment chambers are connected by a communicating vessel. There is a secondary liquid injection hole on the positive terminal plate of the battery cover.

[0011] The high-enthalpy solid-solid phase change material has heat absorption and heat conduction functions, and has preset mechanical properties during the solid-solid phase change process; preferably, the high-enthalpy solid-solid phase change material is one of perovskite, polymer, and polyol; the porous thermal protection material has a skeleton support structure, preferably a combination of nano-scale ceramic porous material, infrared shielding agent, and polymer substrate.

[0012] The top of the exhaust chamber is connected to an explosion-proof valve protective cover, which covers the explosion-proof valve at the top.

[0013] The unidirectional air pressure regulating device includes a multi-layer sealing structure. The multi-layer sealing structure is designed based on temperature-sensitive and pressure-sensitive materials to form a multi-level stiffness seal, realizing adaptive air pressure regulation and unidirectional venting in the event of battery thermal runaway.

[0014] The upper ends of the three sensors are higher than the top surface of the battery cover, and the lower ends of the three sensors are lower than the bottom surface of the battery cover.

[0015] Another object of the present invention is to provide a square battery, including the square battery cover having an adaptive explosion-proof valve and a secondary liquid replenishment chamber.

[0016] The square battery cover of this invention features an adaptive explosion-proof valve that integrates gas composition, pressure, and temperature detection. It can intelligently detect changes in gas composition, pressure, and temperature inside the battery. Furthermore, through a one-way pressure regulating device and a distributed metal lattice that achieves rapid cooling turbulence, it can prevent the gas from overheating and igniting in the air. By incorporating a secondary liquid replenishment chamber, it performs self-liquid replenishment during battery use, reducing the free electrolyte in the square battery and increasing its safety and cycle life. Attached Figure Description

[0017] Figure 1 This is a top view of the square battery cover with explosion-proof valve protection cover of the present invention.

[0018] Figure 2 This is a top view of the square battery cover of the present invention without the explosion-proof valve protective cover.

[0019] Figure 3 This is a bottom view of the battery cover with a secondary liquid replenishment compartment according to the present invention.

[0020] Figure 4 This is a bottom view of the battery cover plate of the present invention without a secondary liquid replenishment tank.

[0021] Figure 5 This is a front view of the battery explosion-proof valve of the present invention.

[0022] Figure 6This is a front view of the square battery cover of the present invention.

[0023] Figure 7 This is a front view of the square battery cover of the present invention without a secondary liquid replenishment compartment.

[0024] Figure 8 This is a left view of the square battery cover of the present invention.

[0025] Figure 9 This is a right view of the square battery cover plate of the present invention without a secondary liquid replenishment compartment.

[0026] Figure 10 This is a top view of the battery explosion-proof valve protective cover of the present invention.

[0027] Figure 11 This is a top view of the battery explosion-proof valve of the present invention.

[0028] Figure 12 This is a bottom view of the battery explosion-proof valve of the present invention.

[0029] Figure 13 This is a diagram of the internal pressure testing device for the square battery of the present invention.

[0030] Figure 14 This is a graph showing the changes in pressure and testing cycles of two different square battery devices according to the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] Please refer to the accompanying drawings. One objective of this invention is to provide a square battery cover 100 with an adaptive explosion-proof valve and a secondary replenishment chamber. The cover includes an explosion-proof valve 1 disposed on the battery cover 100. The explosion-proof valve 1 includes a sensor structure arranged within a circular exhaust chamber of the battery cover 100 and a one-way pressure regulating device 1-5 arranged around the top outer side of the sensor structure. The sensor structure is connected and fixed to the inner wall of the exhaust chamber via a triangular plate 1-1 inscribed within the circle. The triangular plate 1-1 is fixed to the sensor 1-3. The sensor structure includes three sensors 1-3 for detecting the gas composition, pressure, and temperature inside the battery. The axes of the three sensors 1-3 are connected in a triangular shape and are connected by at least two vertically spaced connecting plates (including an upper connecting plate 1-2 and a lower connecting plate 1-6) to form a stable structure. The lower connecting plate 1-6 is made of a porous thermal protection material with low thermal conductivity, ablation resistance, and impact resistance. A circular high-enthalpy solid-solid phase change material is embedded in the thermal protection material to achieve peak heat flux reduction, thereby forming a distributed metal lattice 1-4.

[0033] In this embodiment, the battery cover, through the arrangement of a circular explosion-proof valve structure, can achieve real-time monitoring of changes in internal pressure, temperature, and gas composition. A pressure sensor is used to quickly detect changes in internal gas pressure, a temperature sensor monitors abnormal temperature rises in the battery, and a gas sensor identifies the release of harmful gases in the early stages of thermal runaway, thus responding promptly to potential safety hazards.

[0034] The circular explosion-proof valve is laser-welded to the top cover of the battery via its edge.

[0035] In this embodiment, based on the thermal runaway characteristics of a single battery cell, the design is based on the measured parameters of valve opening pressure, pressure relief path, flue gas temperature, and exhaust rate during thermal runaway of a single battery cell, thereby improving explosion-proof reliability. Its pressure relief structure is nested and fixed with the corresponding exhaust chamber pressure relief hole to meet dust barrier and heat isolation requirements, and realize exhaust guidance design. Through the directional exhaust guidance technology of the battery cover explosion-proof valve, the exhaust chamber spatial structure, flow path, and flue cooling are completed.

[0036] In addition, by using distributed metal lattice turbulent rapid cooling technology, metal lattices are set on the battery pressure relief injection surface in the exhaust chamber, so that the high-temperature flue gas forms turbulence on the injection surface. Based on the flow heat transfer mechanism, the structural morphology of the metal lattice is optimized, which can enhance the flow heat transfer effect. By adjusting the structural morphology, distribution position and distribution density of the metal lattice in the exhaust chamber, the turbulence intensity is enhanced, and high enthalpy phase change materials are used to achieve the rapid cooling effect of the exhaust chamber.

[0037] In some embodiments, the bottom of the battery cover has a secondary electrolyte replenishment chamber 2, which is used to automatically replenish the electrolyte into the battery during battery use. Preferably, the secondary electrolyte replenishment chamber at the bottom of the battery cover is an integral injection-molded structure with the battery cover, replacing the upper gasket structure. During battery use, it can automatically replenish the electrolyte into the battery, solving the problem that current square batteries have too much free electrolyte, the battery absorbs electrolyte in the pores of the electrode plates and separator, and too much electrolyte remains at the bottom of the battery case, which cannot be fully utilized and causes battery safety hazards.

[0038] In some embodiments, the bottom of the secondary electrolyte replenishment chamber has an outlet sealed with pressure-sensitive sealant. During battery use, as the internal pressure of the battery increases, the pressure-sensitive sealant will fail. After failure, the outlet opens, allowing the pre-stored electrolyte inside to be automatically replenished into the battery from the secondary electrolyte replenishment chamber, thus realizing the function and purpose of automatically replenishing electrolyte during battery use.

[0039] In some preferred embodiments, the pressure-sensitive sealant has a pressure resistance of 0-0.6 MPa, or greater than 0.6 MPa. Through timed detachment under constant or higher loads, the sealant material fails and detaches, allowing for fluid replenishment. The specific pressure resistance configuration of the pressure-sensitive sealant can be set according to the battery's needs and is not limited to this. Preferably, the pressure-sensitive sealant is a zinc oxide-polytetrafluoroethylene mixture, an acrylic pressure-sensitive adhesive, or other available materials.

[0040] In some embodiments, there is a secondary liquid filling chamber under the positive terminal plate 4 and the negative terminal plate 5 of the battery cover, and the two secondary liquid filling chambers are connected by a communicating vessel. There is a secondary liquid filling hole 6 on the positive terminal plate of the battery cover, and a primary liquid filling hole 7 next to the negative terminal post of the battery.

[0041] Preferably, the two secondary replenishment chambers have the same structure, size, and are arranged symmetrically. However, in specific implementations, they may differ and are not limited to the shape and size of the embodiments of the present invention.

[0042] In this embodiment, the secondary electrolyte replenishment chamber of the battery cover adopts an irregular structure, and its shape is set according to the shape of the battery's interior. It can be supported between the battery electrode group and the battery cover, and is connected to the outer edge of the integrated injection molded part 10 of the battery cover. It does not affect the airflow discharge of the explosion-proof valve, and can store 5-8% electrolyte, so that the square battery has no free electrolyte.

[0043] Preferably, the total area of ​​the irregularly shaped secondary replenishment chamber is 1000 mm². 2 The battery is 5mm high and 5ml in volume. Specifically, the secondary electrolyte filling chamber is designed using the perforated structure between the battery cover and the battery shell. Secondary electrolyte filling chambers are set below the positive and negative terminal plates, serving as both electrolyte storage and support functions. It does not affect the airflow channel to the explosion-proof valve. During the middle of battery use, the internal pressure rises, the adhesive at the bottom of the secondary electrolyte filling chamber fails, and the electrolyte is automatically injected into the electrode assembly, improving the battery cycle performance. The filling chamber is made of corrosion-resistant, insulating, and heat-insulating materials, reducing the amount of free electrolyte at the bottom of the square battery, ensuring safety performance and improving cycle performance.

[0044] In this embodiment, two integrated injection-molded secondary electrolyte replenishment chambers are provided on the lower side of the positive and negative terminals of the battery cover. These chambers are sealed with pressure-sensitive material to reduce free electrolyte in the battery. As the battery pressure increases during cycling, the pressure-sensitive adhesive material fails, opening the replenishment chambers and allowing the electrolyte to be released a second time. At the same time, the integrated injection-molded secondary electrolyte replenishment chambers can also act as battery electrode support and provide insulation support.

[0045] In this embodiment, the distributed metal dot matrix forms a turbulent rapid cooling device, which enables high-temperature flue gas to form turbulence on the injection surface. Based on the flow heat transfer mechanism, the area of ​​the triangular region where the distributed metal dot matrix is ​​located is 6.15 mm². 2 The structure of the metal dot matrix has a fixed gap between points of 30%-50%, and the area of ​​the embedded points is 2.46 mm². 2 High enthalpy phase change materials.

[0046] In some embodiments, the high-enthalpy solid-solid phase change material has both heat absorption and heat conduction functions, and possesses preset mechanical properties during the solid-solid phase change process; preferably, the high-enthalpy solid-solid phase change material is one of perovskite, polymeric materials, and polyols. By embedding a high-enthalpy solid-solid phase change material inside the protective material, heat is absorbed while exhibiting good thermal conductivity, which provides rapid cooling and turbulence to energy particles such as gases, reducing the contact temperature between thermally runaway gases and the external environment.

[0047] Based on the high enthalpy solid-solid phase change material and the thermal protection material used, the coupled ablation effect of high-temperature and high-speed gas, particles and electric arc generated during the thermal runaway process of high-energy-density power battery on the battery top cover is optimized. The chemical composition and macro- and micro-structure of the composite material are optimized. The intrinsic ablation resistance temperature is improved by comprehensively blending nano-level ceramic porous materials, phase change materials, infrared shielding agents and polymer substrates.

[0048] The square battery cover of this application embodiment monitors the pressure, gas composition, and temperature inside the battery in real time. By setting warning values ​​for pressure, temperature, and gas composition, and employing a non-destructive self-regulating strategy for gas pressure, it determines the stiffness transition temperature and opening pressure of the gas pressure regulating device. This allows for early valve opening, reducing the accumulation of energy substances, lowering the temperature of thermal runaway, and preventing the battery from burning or exploding. At the same time, the thermal protection material below the explosion-proof valve prevents the insulation components of the battery electrode assembly from melting when the thermal runaway temperature is too high, thus supporting the battery cover and electrode assembly structure.

[0049] In some embodiments, the top of the exhaust chamber is connected to an explosion-proof valve protective cover 3, which covers the explosion-proof valve 1 at the top.

[0050] In some embodiments, the unidirectional pressure regulating device 1-5 includes a multi-layer sealing structure. This multi-layer sealing structure, based on temperature-sensitive and pressure-sensitive materials, forms a multi-level rigidity seal, reducing the risk of electrolyte leakage and enabling adaptive pressure regulation as well as unidirectional venting in the event of battery thermal runaway. In this embodiment, the square battery cover, through the regulation of the unidirectional pressure regulating device formed by the multi-layer sealing structure, allows the release of internal energy substances after valve opening, preventing external air from entering the battery and triggering further side reactions, thus reducing the degree of thermal runaway.

[0051] Among them, the upper ends of the three sensors are higher than the top surface of the battery cover, such as 0.92mm higher than the battery cover, the lower ends of the three sensors are lower than the bottom surface of the battery cover, the height of the probes of the three sensors is less than 1.34mm, and they are sealed with rubber seals and explosion-proof valves. The distance between the probes of the three sensors is 1.35mm, and the diameter of the probes is 1.47mm.

[0052] In addition, the lower surface of the square battery cover is connected to the electrode plate connecting pieces of the positive and negative batteries, including the positive electrode connecting piece 8 and the negative electrode connecting piece 9. They are irregularly shaped and are connected to the battery cover by riveting and welding, and are connected to the battery electrode assembly in an S-bend shape.

[0053] The battery cover in this embodiment features a directional pressure relief structure for its exhaust chamber, integrating dust and thermal isolation functions. It incorporates thermally conductive particles and employs interface nanotechnology to enhance particle thermal conductivity. This allows for the detection of gas composition, pressure, and temperature within the battery using sensor structures, enabling joint monitoring of multiple physical signals within the square battery, including force, electricity, heat, gas, and fire. Ultimately, it achieves intelligent battery fault diagnosis and thermal runaway early warning based on high specific energy dynamics derived from the intrinsic reaction sequence of materials and the logical order of multiple sensor signals. The accuracy rate of battery fault early warning is ≥95%, and the early warning lead time for severe thermal runaway is ≥30 minutes with an accuracy of ≥90%.

[0054] The battery cover of this application embodiment is adapted to square batteries. It improves upon the passive safety of current battery thermal runaway by adopting active safety technology. Based on the current intelligent detection technology for batteries, it makes a comprehensive judgment on the internal thermal, electrical, and gaseous aspects of the battery, accurately diagnoses battery faults, and analyzes the corresponding handling methods for the battery, providing a good strategy for the battery system. In addition, when a battery safety fault occurs, it can seriously lead to thermal runaway, fire, and explosion, causing property and personal safety hazards. Through intelligent early warning technology, the battery can provide an early warning 30 minutes before thermal runaway, thereby avoiding serious safety accidents.

[0055] Another objective of this invention is to provide a square battery, including the battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber as described in this invention. The battery is a square battery. Due to the use of the battery cover, the square battery can utilize sensor structures to detect the gas composition, pressure, and temperature inside the battery, achieving joint monitoring of multiple physical signals such as force, electricity, heat, gas, and fire within the square battery. Ultimately, it can achieve intelligent battery fault diagnosis and thermal runaway early warning based on high specific energy dynamics based on the intrinsic reaction time sequence of materials and the logical sequence of multiple sensor signals. The accuracy of battery fault early warning is ≥95%, and the early warning lead time for severe thermal runaway is ≥30 minutes, with an accuracy of ≥90%.

[0056] The square battery cover of this application embodiment can be used in LP2270134 square batteries, and the square batteries can be manufactured using... Figure 13 The device shown is used for pressure testing, testing after sealing, and monitoring of changes in internal gas composition, pressure, and temperature during battery heating.

[0057] A stainless steel heater with a maximum power of 300W can be used. An internal pressure testing system is introduced from the side. The test is conducted using a heat insulation plate 400 and a fixture 200. The fixture has a pressure testing hole 500 on the side. After clamping the battery 300, it is placed in an explosion-proof box. The opening pressure of the battery explosion-proof valve is set. When the battery heating element temperature is 130℃, the battery explosion-proof valve opens automatically. The battery temperature is 150℃, and the maximum battery temperature is 500℃. The battery casing is not damaged. The experimental parameters and corresponding valve values ​​are shown in the table below.

[0058] parameter Opening threshold Explosion-proof valve opening pressure ≤0.6Mpa <![CDATA[Percentage of gas component H2]]> ≤1％ Internal static temperature rise rate ≤0.02℃ / min

[0059] The prepared prismatic battery, model LP2270134, uses the same system. The positive electrode material is a high-nickel ternary material, and the negative electrode material is graphite. One type uses a conventional single-fill battery, and the other type uses a secondary replenishment device. The nominal capacity of the battery is 25Ah, and the standard electrolyte filling amount is 62g. The conventional single-fill battery manufacturing process is as follows: sheet preparation, winding, hot pressing, casing, peripheral welding and leak testing, drying, electrolyte filling, open-end formation, and closed-end formation. The initial electrolyte filling amount is 50g. After pre-formation and vacuuming, 12g of electrolyte is added, and then the battery is sealed and formed to obtain a conventional single-fill battery.

[0060] The secondary electrolyte filling device battery's manufacturing process is the same as that of the primary electrolyte filling battery. For example, if the electrolyte density is 1.2 g / cm³, and the secondary electrolyte filling chamber has a volume of 8 ml, the electrolyte volume is 9.6 g, and the primary electrolyte filling volume is 47 g. After the battery is left to stand for 24 hours, pre-formation is performed. The pre-formed battery then receives 7 g of secondary electrolyte, and 8 g of electrolyte is injected into the secondary electrolyte filling chamber for secondary self-replenishment. After sealing the primary and secondary filling ports, formation is then performed to obtain the secondary electrolyte filling device battery. Both types of batteries were subjected to room temperature cycling tests. The pressure changes of the two types of batteries during the cycling process are shown in the table below.

[0061] Loop count One-time liquid-filled battery (kPa) Secondary electrolyte replenishment device battery kPa 1 20.00 18.00 400 57.85 55.80 800 77.97 75.89 1200 95.43 92.67 1600 126.87 124.12 2000 170.66 168.24

[0062] As shown in the table above, the pressure increase of the batteries in both devices during cycling is basically the same, with initial pressures of 20 kPa and 18 kPa, and battery pressures at the end of 2000 cycles of 170.66 kPa and 168.24 kPa, respectively. Figure 14It can be seen that the initial cycle performance of the battery with primary electrolyte injection and the battery with secondary electrolyte injection is the same. When the cycle reaches 1600 cycles, the cycle decay of the battery with secondary electrolyte injection remains unchanged, while the capacity decay rate of the battery with primary electrolyte injection increases. After 1917 cycles, the capacity retention rates of the two batteries are 74.91% and 70.62%, respectively, with the capacity retention rate being 4.29% higher. Due to the increased pressure at 1600 cycles, which exceeds the upper limit of the pressure-sensitive adhesive in the secondary electrolyte replenishment tank, the pressure-sensitive adhesive fails, allowing the electrolyte in the secondary electrolyte replenishment tank to be automatically replenished into the electrode group, resulting in good battery cycle performance and improved battery cycle performance.

[0063] Comparative example:

[0064] Batteries made with conventional battery caps lack a secondary liquid filling chamber and an integrated sensor for thermal, electrical, and gas coupling. The batteries are manufactured using the aforementioned primary liquid filling battery manufacturing method. The experiment uses a stainless steel heater with a maximum power of 300W. Figure 13 The device shown is clamped for pressure testing. When the battery is placed in the explosion-proof box, the battery explosion-proof valve opens automatically. When the battery heating element temperature is 130°C, the battery temperature is 200°C. The highest battery temperature is 900°C, and the battery casing is completely damaged.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0066] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0067] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment compartment, characterized in that, The system includes an explosion-proof valve, comprising a sensor structure disposed within a circular vent chamber of the battery cover and a one-way pressure regulating device disposed around the top outer side of the sensor structure. The sensor structure is connected and fixed to the inner wall of the vent chamber via a triangular plate inscribed within the circle. The sensor structure includes three sensors for detecting the gas composition, pressure, and temperature inside the battery: a pressure component sensor, a pressure sensor, and a temperature sensor. The axes of the three sensors form a triangle and are connected by at least two parallel and spaced connecting plates. A stable structure is formed; the lower connecting plate, made of a porous thermal protection material with low thermal conductivity, ablation resistance, and impact resistance, incorporates circular high-enthalpy solid-solid phase change materials to reduce peak heat flux, forming a distributed metal lattice; a secondary liquid replenishment chamber is located at the bottom of the battery cover, used to automatically replenish electrolyte into the battery during use; the unidirectional air pressure regulating device includes a multi-layer sealing structure, which is designed based on temperature-sensitive and pressure-sensitive materials to form a multi-level stiffness seal, realizing adaptive air pressure regulation and unidirectional venting in case of battery thermal runaway.

2. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment tank according to claim 1, characterized in that, The outlet at the bottom of the secondary electrolyte replenishment chamber is sealed with pressure-sensitive sealant. During battery use, as the internal pressure of the battery increases, the pressure-sensitive sealant fails, allowing the electrolyte inside to be automatically replenished from the secondary electrolyte replenishment chamber into the battery.

3. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber as described in claim 2, characterized in that, The pressure-sensitive sealant has a pressure resistance of 0-0.6 MPa. If the pressure exceeds 0.6 MPa, the pressure-sensitive sealant will fail.

4. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber as described in claim 2, characterized in that, The pressure-sensitive sealant is made of a zinc oxide-polytetrafluoroethylene mixture or an acrylic pressure-sensitive adhesive.

5. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber as described in claim 2, characterized in that, There is a secondary liquid replenishment chamber under the positive and negative terminal plates of the battery cover. The two secondary liquid replenishment chambers are connected by a communicating vessel. There is a secondary liquid injection hole on the positive terminal plate of the battery cover.

6. The square battery cover with an adaptive explosion-proof valve and a secondary replenishment tank according to claim 1, characterized in that, The high enthalpy solid-solid phase change material has heat absorption and heat conduction functions, and has preset mechanical properties during the solid-solid phase change process; the high enthalpy solid-solid phase change material is one of perovskite, polymer, and polyol.

7. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber according to claim 1, characterized in that, The porous thermal protection material has a skeleton support structure and is a combination of one or more of nano-scale ceramic porous materials, infrared shielding agents, and polymer substrates.

8. The square battery cover with an adaptive explosion-proof valve and a secondary replenishment tank according to claim 1, characterized in that, The top of the circular exhaust chamber is connected to an explosion-proof valve protective cover, which covers the explosion-proof valve at the top.

9. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber according to claim 1, characterized in that, The upper ends of the three sensors are higher than the top surface of the battery cover, and the lower ends of the three sensors are lower than the bottom surface of the battery cover.

10. A square battery, characterized in that, Includes the square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment chamber as described in any one of claims 1-9.

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