Square battery cover plate with self-adaptive anti-explosion valve and secondary liquid supplementing bin and square battery

Abstract

The invention discloses a square battery cover plate with a self-adaptive anti-explosion valve and a secondary liquid supplementing bin and a square battery. The square battery cover plate comprises an anti-explosion valve, and the anti-explosion valve comprises a sensor structure arranged in a round exhaust bin of the battery cover plate and a one-way air pressure adjusting device arranged on the periphery of the outer side of the top of the sensor structure. The sensor structure comprises sensors for detecting gas components, pressure and temperature in the battery, and the connecting lines of the axes of the three sensors are triangular and are connected through at least two connecting plates which are vertically separated from each other; a circular high-enthalpy-value solid-solid phase change material for realizing peak heat flow reduction is embedded into a thermal protection material of a lower-layer connecting plate made of a porous thermal protection material with low thermal conductivity, ablation resistance and impact resistance, so that a distributed metal dot matrix is formed; and a secondary electrolyte supplementing bin is arranged at the bottom of the battery cover plate and is used for automatically supplementing the stored electrolyte into the battery. According to the invention, gas composition, pressure and temperature changes in the battery are intelligently detected to realize intelligent pressure relief, explosion prevention and automatic liquid supplement.

Description

Technical Field

[0001] The present invention relates to the technical field of square batteries, and in particular to a square battery cover plate and a square battery with an adaptive explosion-proof valve and a secondary liquid replenishing tank. Background Art

[0002] There are three main types of mainstream lithium battery packaging, namely cylindrical, soft-pack and square batteries. According to the research report released by Guolian Securities, from the perspective of market application, square batteries account for more than 90% of the domestic power and energy storage market. The structural safety design of the battery is crucial. Square batteries are generally composed of a battery cover and a battery shell. The design of the battery cover is particularly important. The battery cover consists of a top cover plate, positive and negative poles, an explosion-proof device, and a liquid injection hole. When the battery thermally runs away, the temperature and pressure inside the battery increase. When the pressure exceeds the explosion-proof valve tolerance pressure, the passive air pressure explosion-proof valve of the battery cover opens, releasing gas or spraying flames, and even burning and exploding with the outside air. When the battery thermally runs away, the internal temperature of the battery is as high as 900°C or above, causing the battery shell and battery cover plastic to melt, causing heat to spread. There is no advance warning of the temperature and gas inside the battery shell, resulting in the existence of safety hazards of square batteries.

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

[0004] Chinese invention patent CN201478351U involves a first electrode and a second electrode of a square battery cover, wherein the second electrode includes a top cover, a bottom plate and a safety film, wherein the safety film is located on the bottom plate, and its center is depressed downward and connected to the bottom plate, so as to achieve pressure relief and power off, thereby preventing the battery from exploding and endangering personal safety. This invention adopts a passive pressure relief method, and cannot provide early warning and treatment of battery safety hazards, and can only reduce the severity of battery safety disasters to a certain extent, but cannot actively control and reduce the frequency of accidents. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and to provide a square battery cover and a square battery with an adaptive explosion-proof valve and a secondary liquid replenishing tank; the square battery cover is integrated with an intelligent sensor for monitoring the gas, temperature and pressure in the square battery, and is provided with a one-way air pressure regulating device, a distributed metal lattice for realizing rapid cooling turbulence and a secondary liquid replenishing tank, aiming to solve the problem that there is too much free electrolyte in the existing square battery, which affects the electrical performance and safety performance of the battery, or there is a safety hazard in the passive opening of the valve when the battery is thermally runaway.

[0006] One object of the present invention is to provide a square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment bin, including an explosion-proof valve, the explosion-proof valve including a sensor structure arranged in a circular exhaust bin of the battery cover and a one-way air pressure regulating device arranged around the outer side of the top of the sensor structure; the sensor structure is connected and fixed to the inner wall of the exhaust bin through a triangular plate inscribed in a circle, the sensor structure includes three sensors for detecting the gas composition, pressure and temperature inside the battery, the axis line of the three sensors is triangular and connected by at least two vertically spaced connecting plates to form a stable structure; 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 is embedded with a circular high enthalpy solid-solid phase change material for achieving peak heat flow reduction to form a distributed metal lattice; there is a secondary liquid replenishment bin at the bottom of the battery cover, which is used to automatically replenish the electrolyte in the battery during the use of the battery.

[0007] Preferably, the liquid outlet at the bottom of the secondary liquid replenishment tank is sealed with a pressure-sensitive sealant. During the use of the battery, as the internal pressure of the battery increases, the pressure-sensitive sealant fails, causing the internal electrolyte to automatically replenish into the battery from the secondary liquid replenishment tank.

[0008] The pressure-sensitive sealant has a pressure resistance of 0-0.6 MPa. If the pressure resistance is greater than 0.6 MPa, the pressure-sensitive sealant will fail.

[0009] Wherein, the material of the pressure-sensitive sealant is a zinc oxide-polytetrafluoroethylene mixture or an acrylic pressure-sensitive adhesive.

[0010] There is a secondary liquid replenishing tank under each of the positive and negative end plates of the battery cover, the two secondary liquid replenishing tanks are connected by a connecting vessel, and there is a secondary liquid injection hole on the positive end plate of the battery cover.

[0011] Among them, 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, high molecular polymer and polyol; the porous thermal protection material has a skeleton support structure, preferably a nano-ceramic porous material, an infrared shielding agent, and a composite of one or more of a polymer substrate.

[0012] Wherein, the top of the exhaust bin is connected to an explosion-proof valve protection cover, and the explosion-proof valve protection cover covers the explosion-proof valve at the upper end.

[0013] Among them, the one-way 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, thereby realizing adaptive air pressure regulation and opening one-way exhaust when the battery has thermal runaway.

[0014] Among them, the upper ends of the three sensors are higher than the top end surface of the battery cover, and the lower ends of the three sensors are lower than the bottom end surface protruding from the battery cover.

[0015] Another object of the present invention is to provide a square battery, including the square battery cover with the adaptive explosion-proof valve and the secondary liquid replenishing tank.

[0016] The square battery cover of the present invention has an explosion-proof valve which is an adaptive explosion-proof valve that integrates gas composition, pressure and temperature detection. It can intelligently detect the gas composition, pressure and temperature changes inside the battery. In addition, through a one-way air pressure regulating device and a distributed metal lattice that realizes rapid cooling turbulence, excessive gas temperature and air combustion can be avoided. By setting up a secondary liquid replenishing tank, self-liquid replenishing technology is performed during the use of the battery, thereby reducing the free electrolyte of the square battery and increasing the safety and cycle life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 2 It is a top view of a square battery cover plate without an explosion-proof valve protection cover according to the present invention.

[0019] Figure 3 It is a bottom view of the battery cover with a secondary liquid replenishing tank of the present invention.

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

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

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

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

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

[0025] Fig. 9 It is a right side view of a square battery cover without a secondary liquid replenishing tank according to the present invention.

[0026] Fig.10 It is a top view of the battery explosion-proof valve protection cover of the present invention.

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

[0028] Fig.12 1. It is a bottom view of the battery explosion-proof valve of the present invention.

[0029] Fig.13 This is a diagram of a square battery internal pressure testing device according to the present invention.

[0030] Fig.14 It is a graph showing the changes in test cycles and pressure of square batteries of two different devices of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Please refer to the drawings of the specification. One purpose of the embodiment of the present invention is to provide a square battery cover 100 with an adaptive explosion-proof valve and a secondary liquid replenishment tank, including an explosion-proof valve 1, which is arranged on the battery cover 100, wherein the explosion-proof valve 1 includes a sensor structure arranged in a circular exhaust bin of the battery cover 100 and a one-way air pressure regulating device 1-5 arranged around the outer side of the top of the sensor structure; the sensor structure is connected and fixed to the inner wall of the exhaust bin by a triangular plate 1-1 inscribed in the circle, wherein the triangular plate 1-1 and the sensor 1-3 are fixed The sensor structure includes three sensors 1-3 for detecting the gas composition, pressure and temperature inside the battery. The axis lines of the three sensors 1-3 are triangular and 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 thermal protection material of the lower connecting plate 1-6, which is made of a porous thermal protection material with low thermal conductivity, ablation resistance and impact resistance, is embedded with a circular high enthalpy solid-solid phase change material for achieving peak heat flow reduction to form a distributed metal lattice 1-4.

[0033] In the embodiment of the present application, the battery cover plate can monitor the changes in pressure, temperature and gas composition inside the battery through the arrangement of the circular explosion-proof valve structure, use a pressure sensor to quickly detect changes in internal gas pressure, a temperature sensor to monitor abnormal temperature rise of the battery, and a gas sensor to identify the release of harmful gases in the early stage of thermal runaway, so as to respond to potential safety hazards in a timely manner.

[0034] Wherein, the circular explosion-proof valve is laser welded on the battery top cover through the edge.

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

[0036] In addition, through the distributed metal lattice turbulent rapid cooling technology, by setting a metal lattice on the battery pressure relief injection surface in the exhaust bin, the high-temperature flue gas forms turbulence on the injection surface, and based on the flow heat transfer mechanism, the structural form of the metal lattice is optimized, so that the flow heat transfer effect can be enhanced; by adjusting the structural form, distribution position and distribution density of the metal lattice in the exhaust bin, the turbulence intensity is enhanced, and the high enthalpy phase change material is used to achieve the exhaust bin rapid cooling effect.

[0037] In some embodiments, the bottom of the battery cover is provided with a secondary liquid replenishing tank 2, which is used to automatically replenish the electrolyte therein into the battery during the use of the battery. Preferably, the secondary liquid replenishing tank at the bottom of the battery cover is an integral injection molding structure with the battery cover, replacing the upper gasket structure, and can automatically replenish the electrolyte into the battery during the use of the battery, thereby solving the problem of excessive free electrolyte in the current square battery, the battery adsorbing electrolyte in the pores of the electrode and the diaphragm, and excessive electrolyte remaining at the bottom of the battery shell, which cannot be fully utilized, causing potential safety hazards to the battery.

[0038] In some embodiments, the secondary liquid replenishment tank has a liquid outlet at the bottom, and the liquid outlet is sealed with a pressure-sensitive sealant. During the use of the battery, as the internal pressure of the battery increases, the pressure-sensitive sealant will fail. After failure, the liquid outlet opens, allowing the internal pre-stored electrolyte to be automatically replenished into the battery from the secondary liquid replenishment tank, thereby achieving the function and purpose of automatically replenishing the electrolyte during the use of the battery.

[0039] In some preferred embodiments, the pressure-resistant pressure of the pressure-sensitive sealant is 0-0.6Mpa, which is greater than 0.6Mpa. The adhesive material fails and falls off by timed shedding under a constant or higher load, so that liquid can be replenished. The specific pressure-resistant configuration of the pressure-sensitive sealant can be set according to the needs of the battery, but is not limited thereto. Preferably, the material of the pressure-sensitive sealant is a zinc oxide-polytetrafluoroethylene mixture, or an acrylic pressure-sensitive adhesive, or other available materials.

[0040] In some embodiments, there is a secondary liquid replenishing tank under the positive terminal plate 4 and the negative terminal plate 5 of the battery cover, and the two secondary liquid replenishing tanks are connected by a connecting vessel. There is a secondary liquid filling hole 6 on the positive terminal plate of the battery cover. In addition, there is a primary liquid filling hole 7 next to the negative electrode of the battery.

[0041] Preferably, the two secondary liquid replenishment tanks have the same structure, are the same size, and are symmetrically arranged. During specific implementation, they may be different and are not limited to the shapes and sizes of the embodiments of the present invention.

[0042] In the embodiment of the present application, the secondary liquid replenishing tank of the battery cover adopts a special-shaped structure, and its shape is set according to the shape of the interior of the battery. It can be supported between the battery pole 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 at the same time can store 5-8% of the electrolyte, so that the square battery has no free electrolyte.

[0043] Preferably, the total area of ​​the special-shaped structure of the secondary liquid replenishment tank is 1000mm 2 , height 5mm, volume 5ml. Specifically, the secondary liquid replenishing tank is designed by utilizing the pore structure between the battery cover and the plate battery shell. Secondary liquid storage tanks are respectively arranged under the positive and negative terminal plates, which have both liquid storage and support functions, and do not affect the battery air flow channel to the explosion-proof valve. In the middle of battery use, the internal pressure rises, and the glue at the bottom of the secondary liquid filling tank fails. The electrolyte is automatically injected into the pole group to improve the battery cycle performance; the liquid filling tank is made of corrosion-resistant, insulating and heat-insulating materials to reduce the amount of free electrolyte at the bottom of the square battery, ensure safety performance and improve cycle performance.

[0044] In the embodiment of the present application, two integrated injection-molded secondary liquid replenishing tanks are provided on the lower side of the poles on the positive and negative sides of the battery cover and sealed by pressure-sensitive materials to reduce free electrolyte in the battery. When the pressure of the battery increases during circulation, the pressure-sensitive adhesive material fails and the liquid replenishing tank is opened, so that the electrolyte is released for a second time. At the same time, the integrated injection-molded secondary liquid replenishing tank can act as a battery pole group bracket and play an insulating support role.

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

[0046] In some embodiments, 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, high molecular polymer and polyol. By embedding a high enthalpy solid-solid phase change material inside the protective material, it absorbs heat and has good heat conduction, plays a rapid cooling turbulence role on energy particles such as gas, and reduces the contact temperature between the thermal runaway gas and the outside world.

[0047] According to the high enthalpy solid-solid phase change material and the coupled ablation effect of high-temperature and high-speed gas, particles and arc on the battery top cover generated by the thermal protection material used in the thermal runaway process of the high-energy-density power battery, the chemical composition and macro-microstructure of the composite material are optimized, and a comprehensive formulation of nano-ceramic porous materials, phase change materials, infrared shielding agents and polymer substrates is adopted to achieve an increase in its intrinsic ablation resistance temperature.

[0048] The square battery cover of the embodiment of the present application monitors the pressure, gas composition and temperature in the battery in real time, sets early warning values ​​for pressure, temperature and gas composition, and adopts a lossless self-regulation strategy for air pressure to determine the stiffness transition temperature and opening pressure of the air pressure regulating device. This allows the valve to be opened in advance, reduce the accumulation of energy substances, lower the temperature of thermal runaway, and achieve a battery without combustion or explosion. At the same time, the thermal protection material under the explosion-proof valve prevents the insulating component of the battery pole group from melting when the thermal runaway temperature is too high, thereby supporting the battery cover and the pole group structure.

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

[0050] In some embodiments, the one-way air pressure regulating device 1-5 includes a multi-layer sealing structure, which is designed based on temperature-sensitive and pressure-sensitive materials to form a multi-level rigidity seal, reduce the risk of electrolyte leakage, and realize adaptive air pressure regulation and one-way exhaust when the battery is opened during thermal runaway. The square battery cover of the embodiment of the present application, through the regulation of the one-way air pressure regulating device formed by the multi-layer sealing structure, can release the energy substances inside the battery after opening the valve, prevent the outside air from entering the battery to cause more side reactions, and reduce the degree of thermal runaway reaction.

[0051] Among them, the upper ends of the three sensors are higher than the top end surface of the battery cover, such as 0.92mm higher than the battery cover, and the lower ends of the three sensors are lower than the bottom end surface protruding from the battery cover. The heights of the probes of the three sensors are lower than 1.34mm, and they are sealed with sealing rubber 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 with the plate connecting pieces of the positive and negative batteries, including the positive connecting piece 8 and the negative connecting piece 9, which are of special-shaped structures, connected to the battery cover by rivet welding, and connected to the battery pole group in an S-shaped shape.

[0053] The battery cover in the embodiment of the present application has a directional pressure relief structure for the exhaust bin, integrated dust isolation and heat isolation functions, and is provided with heat-conductive particles. The interface nanotechnology is used to enhance the thermal conductivity of the particles, and the sensor structure can be used to detect the gas composition, pressure, and temperature inside the battery, so as to realize the joint monitoring of multiple physical signals of "force-electricity-heat-gas-fire" in the square battery, and ultimately realize high specific energy power based on the intrinsic reaction timing of the material and the logical sequence of multiple sensor signals, realize intelligent battery fault diagnosis and thermal runaway warning, and realize the accuracy of battery fault warning ≥95%, the warning lead time of severe thermal runaway ≥30min, and the accuracy ≥90%.

[0054] The battery cover of the embodiment of the present application is suitable for square batteries. It adopts active safety technology after improving the passive safety of current battery thermal runaway. It uses the intelligent detection technology of the current battery to make a comprehensive judgment on the heat, electricity and gas inside the battery, accurately judge the battery failure, and analyze the corresponding processing method of the battery, so as to provide a good strategy for the battery system. In addition, when a battery safety failure occurs, it will seriously cause thermal runaway and fire and explosion, causing property and life safety. Through the intelligent early warning technology, the battery can be warned 30 minutes before thermal runaway, thereby avoiding serious safety accidents.

[0055] Another purpose of an embodiment of the present invention is to provide a square battery, including the battery cover with an adaptive explosion-proof valve and a secondary liquid replenishing tank according to the embodiment of the present invention. The battery is a square battery. The square battery, due to the use of the battery cover, can use the sensor structure to detect the gas composition, pressure, and temperature inside the battery, and realize the joint monitoring of multiple physical signals of "force-electricity-heat-gas-fire" in the square battery, and finally realize high specific energy power based on the intrinsic reaction timing of the material and the logical order of multiple sensor signals, realize intelligent battery fault diagnosis and thermal runaway warning, and achieve battery fault warning accuracy ≥ 95%, severe thermal runaway warning advance time ≥ 30min, and accuracy ≥ 90%.

[0056] The square battery cover plate of the embodiment of the present application can be used for LP2270134 square battery, and the square battery produced can be used Fig.13 The device shown performs pressure testing, testing after sealing, and monitoring changes in gas composition, pressure, and temperature inside the battery during battery heating.

[0057] Among them, a stainless steel heater with a maximum power of 300W can be used, an internal pressure testing system is introduced on the side, and a heat insulation board 400 and a fixture 200 are used for testing. There is a pressure measuring hole 500 on the side of the fixture. The battery 300 is clamped and placed in an explosion-proof box. The opening pressure of the battery explosion-proof valve is set. When the temperature of the battery heating plate is 130°C, the battery explosion-proof valve automatically opens. The battery temperature is 150°C, the maximum battery temperature is 500°C, and the battery shell is not damaged. The corresponding valve opening values ​​of the experimental parameters are shown in the following table.

[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 square battery model is LP2270134, using the same system, the positive electrode material is a high-nickel ternary material, the negative electrode material is a graphite material, one uses a conventional primary liquid injection battery, and the other uses a secondary liquid filling device battery. The nominal capacity of the battery is 25Ah, and the standard liquid filling amount of the battery is 62g. The conventional primary liquid injection battery manufacturing process is sheet making, winding, hot pressing, shelling, peripheral welding and leak testing, drying, liquid filling, open formation, and closed formation. The battery's primary liquid filling amount is 50g. The battery is pre-formed and vacuumed, then 12g of liquid is filled, and then it is sealed and formed to obtain a conventional primary liquid injection battery.

[0060] The secondary liquid injection device battery, the battery manufacturing process is consistent with the primary liquid injection battery manufacturing process. For example, the density of the electrolyte used is 1.2g / cm3, and the volume of the secondary liquid filling tank is 8ml, the amount of electrolyte that can be injected is 9.6g, and the battery primary injection amount is 47g. The battery is pre-formed after standing for 24 hours. The pre-formed battery is refilled with 7g of liquid for the second time, and 8g of electrolyte is injected into the secondary liquid filling tank for secondary self-refilling. Then the primary injection port and the secondary injection are sealed, and then formation is carried out to obtain a secondary liquid injection device battery. The two batteries obtained were subjected to room temperature cycle tests. During the test, the pressure changes of the two batteries during the cycle process are as shown in the following table.

[0061] Cycle times Primary injection battery Kpa Secondary refilling 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 growth of the batteries of the two devices during the cycle is basically the same, with the initial pressure being 20KPa and 18KPa, and the pressure of the batteries after 2000 cycles is 170.66KPa and 168.24KPa. Fig.14It can be seen that the initial cycle performance of the single-filling battery and the secondary-filling battery is consistent. When the cycle reaches 1600 times, the cycle attenuation of the battery of the secondary-filling device remains unchanged, and the capacity attenuation rate of the battery of the single-filling device increases. After 1917 cycles, the capacity retention rates of the battery of the secondary-filling device and the single-filling battery are 74.91% and 70.62%, respectively, and the capacity retention rate is 4.29% higher. Due to the increase in pressure after 1600 cycles, it exceeds the upper limit of the pressure-sensitive adhesive in the secondary filling tank, and the pressure-sensitive adhesive fails, causing the electrolyte in the secondary filling tank to automatically replenish into the electrode group. The battery cycle performance is good, thereby improving the battery cycle performance.

[0063] Comparative Example:

[0064] The battery made with conventional battery cover does not have a secondary liquid filling chamber and thermal, electrical and gas coupling integrated sensors. The battery is made according to the above-mentioned method of making a single liquid filling battery. The experiment uses a stainless steel heater with a maximum power of 300W, such as Fig.13 The device shown is clamped for pressure testing. The battery is placed in an explosion-proof box. The battery explosion-proof valve opens automatically. When the temperature of the battery heating plate is 130°C, the battery temperature is 200°C, the maximum battery temperature is 900°C, and the battery shell is completely damaged.

[0065] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and 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 considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is therefore intended that all changes falling within the meaning and range of equivalent elements of the claims are included in the present invention.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes 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 tank, characterized in that: The invention comprises an explosion-proof valve, wherein the explosion-proof valve comprises a sensor structure arranged in a circular exhaust chamber of a battery cover and a one-way air pressure regulating device arranged around the outer side of the top of the sensor structure; the sensor structure is connected and fixed to the inner wall of the exhaust chamber by a triangular plate inscribed in a circle, and the sensor structure comprises three sensors for detecting the gas composition, pressure and temperature inside the battery, the axis lines of the three sensors are triangular and connected by at least two vertically spaced connecting plates to form a stable structure; a circular high enthalpy solid-solid phase change material for achieving 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 to form a distributed metal lattice; a secondary liquid replenishing tank is provided at the bottom of the battery cover, which is used to automatically replenish the electrolyte in the battery during the use of the battery.

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

3. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment tank according to claim 2, characterized in that: The pressure-sensitive sealant has a pressure resistance of 0-0.6 MPa. If the pressure is greater than 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 tank according to claim 2, characterized in that: The material of the pressure-sensitive sealant is 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 tank according to claim 2, characterized in that: There is a secondary liquid replenishing tank under each of the positive and negative end plates of the battery cover, and the two secondary liquid replenishing tanks are connected by a connecting vessel. There is a secondary liquid injection hole on the positive end plate of the battery cover.

6. The square battery cover with an adaptive explosion-proof valve and a secondary liquid 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; preferably, the high enthalpy solid-solid phase change material is one of perovskite, high molecular polymer and polyol; the porous thermal protection material has a skeleton support structure, preferably a nano-ceramic porous material, an infrared shielding agent, and a composite of one or more of a polymer substrate.

7. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment tank according to claim 1, characterized in that: The top of the circular exhaust bin is connected to an explosion-proof valve protection cover, and the explosion-proof valve protection cover covers the explosion-proof valve at the upper end.

8. The square battery cover with an adaptive explosion-proof valve and a secondary liquid replenishment tank according to claim 1, characterized in that: The one-way air pressure regulating device comprises a multi-layer sealing structure, which is designed based on temperature-sensitive and pressure-sensitive materials to form a multi-level stiffness seal, thereby realizing adaptive air pressure regulation and opening one-way exhaust when the battery is under thermal runaway.

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

10. A square battery, characterized in that: A square battery cover having an adaptive explosion-proof valve and a secondary liquid replenishing tank as described in any one of claims 1 to 9.

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