Lithium battery structure with notched composite cap

Abstract

The application relates to the technical field of batteries, in particular to a lithium battery structure with a notched composite cover cap, which comprises a battery main body, the outer surface of the battery main body is fixedly installed with a battery shell, the top of the battery main body is fixedly connected with a cover cap groove steel sheet, and the bottom of the cover cap groove steel sheet is fixedly connected with a PCB board. During application of the technical scheme, the cover cap groove steel sheet, the cover cap groove aluminum sheet and the cover cap sealing rubber ring are arranged in cooperation with the lithium battery main body, so that the cover cap groove steel sheet enhances structural strength, assists in conduction and cooperates with a notch to buffer stress during use, the aluminum sheet cooperates with the steel sheet and the rubber ring to stably guarantee packaging and electrical connection by virtue of the light and conductive characteristics, the rubber ring is sealed and leakproof and is adapted to the notch to guarantee structural stability, and therefore the effects of improving the structural stability of the cover cap and the reliability of electrical connection are achieved, and the problems of low assembly precision and large matching deviation caused by combination of a single metal sheet and a sealing element in a traditional cover cap are solved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a lithium battery structure with a notched composite cap. Background Technology

[0002] Currently, lithium batteries occupy a core position in portable electronic devices, new energy vehicles, and energy storage systems due to their advantages such as high energy density and long cycle life. However, the safety performance of lithium batteries remains a key factor restricting their application expansion. Among them, the battery cap, as a core component connecting the cell to the external circuit, directly affects the battery's assembly accuracy, sealing reliability, and safety protection capabilities. Existing lithium battery caps mostly adopt a combination structure of a single metal sheet and a sealing element, which generally has the following shortcomings: On the one hand, the assembly process relies on manual or simple tooling for positioning, resulting in low precision in the fit between the metal sheet and the sealing element. This can easily lead to uneven sealing gaps due to assembly deviations, causing the risk of electrolyte leakage. On the other hand, traditional caps have limited structural strength and lack buffering and protection designs for extreme working conditions, resulting in weak safety protection capabilities.

[0003] Of particular concern is the lack of effective explosion protection in existing battery cap structures. During long-term use of lithium batteries, internal short circuits, overcharging and over-discharging, cell aging, or external impacts can cause abnormal reactions within the battery, leading to short circuits. When a short circuit occurs, a large amount of heat is instantly generated inside the battery, causing the temperature to rise rapidly. When the temperature exceeds the electrolyte decomposition threshold (usually between 130°C and 200°C), the electrolyte decomposes to produce flammable gases such as hydrogen and carbon monoxide, and the internal pressure rises rapidly. Because traditional cap structures lack stress buffering design and the metal sheets... The connection strength with the seal is insufficient to withstand the rapidly increasing internal pressure, which will eventually lead to the rupture or even explosion of the battery casing. The battery explosion will not only produce open flames and ignite surrounding combustibles, causing direct damage to equipment and the environment; more seriously, the high-temperature fragments and shock waves generated by the explosion can easily cause burns, impact injuries and other safety threats to the human body. At the same time, during the explosion, electrolyte and internal harmful substances (such as heavy metals and fluorides) will be released into the air or seep into the soil and water, causing serious environmental pollution and posing long-term potential hazards to the ecosystem and human health. Summary of the Invention

[0004] To improve safety during existing battery applications, this application provides a lithium battery structure with a notched composite cap.

[0005] This application provides a lithium battery structure with a notched composite cap, employing the following technical solution: It includes a battery body, with a battery casing fixedly mounted on the outer surface of the battery body. A cap groove steel sheet is fixedly connected to the top of the battery body. A PCB board is fixedly connected to the bottom of the cap groove steel sheet. A lithium battery positive electrode connection steel sheet is fixedly connected to the bottom of the PCB board. A lithium battery positive electrode connection aluminum sheet is fixedly connected to the bottom of the lithium battery positive electrode connection steel sheet. A lithium battery negative electrode sheet is fixedly connected to the outer top of the cap groove steel sheet. A lithium battery negative electrode connection aluminum sheet is fixedly connected to the outer top of the battery body. The lithium battery negative electrode sheet and the lithium battery negative electrode connection aluminum sheet are electrically connected. The lithium battery positive electrode connection steel sheet and the lithium battery positive electrode connection aluminum sheet are also electrically connected. A battery positive electrode connection pin is fixedly connected to one side of the bottom of the cap groove steel sheet. A lithium battery positive electrode body is fixedly connected to the middle of the top of the cap groove steel sheet. The bottom of the lithium battery positive electrode body is electrically connected to the lithium battery positive electrode connection steel sheet.

[0006] Optionally, the battery body and battery casing are cylindrical in shape, and the outer corners of the battery body and battery casing are rounded.

[0007] Optionally, the battery body is equipped with a BMS management module inside, and a cap sealing ring is fixedly connected to the bottom of the cap groove steel sheet.

[0008] Optionally, the cap sealing ring is made of methyl vinyl silicone rubber and is fitted and sealed on the bottom outer side of the cap groove steel sheet.

[0009] Optionally, the battery casing includes an elastic protective shell and a fusible connection assembly. The elastic protective shell is fixedly installed on the outside of the battery body. A cavity is opened inside the elastic protective shell, and the cavity is filled with flame-retardant fluid. A support assembly is fixedly installed on the outside of the elastic protective shell.

[0010] Optionally, the fusible connection assembly includes an annular groove, which is linearly arranged at equal intervals on the outer surface of the battery body. The inner side of the annular groove is connected to the inner side of the battery body. A sealing ring is fixedly installed inside each annular groove, and fusible connections are provided at equal intervals on the outer surface of the sealing ring.

[0011] Optionally, the fusion assembly includes a connecting groove, which is arranged in a ring at equal intervals on the outer surface of the sealing ring. The inner side of the connecting groove is connected to the interior of the battery body. A fusion sealing plug is fixedly connected inside the connecting groove. The fusion sealing plug is made of Wood alloy and has a maximum temperature resistance of 70 degrees Celsius.

[0012] Optionally, an outer buffer spring frame is fixedly connected to the inner side of the cavity, and an inner buffer spring frame is fixedly installed on the inner side of the cavity. The inner buffer spring frame and the outer buffer spring frame are fixedly connected to each other.

[0013] Optionally, the elastic protective shell is made of elastic metal, including nanostructured copper-tantalum-lithium alloy, high-elasticity titanium alloy, high-elasticity aluminum alloy, pure aluminum, 3J1 high-elasticity alloy, beryllium bronze, and nickel-based alloy.

[0014] Optionally, the outer support assembly includes an outer support steel frame, which is fixedly connected to the outside of the elastic protective shell. A top reinforcing ring is fixedly connected to the top of the outer support steel frame, and the top reinforcing ring is sleeved on the outside of the cap groove steel sheet. A bottom reinforcing circular plate is fixedly installed at the bottom of the outer support steel frame, and the bottom reinforcing circular plate covers the bottom of the battery body. Explosion extension deformation reserved grooves are evenly spaced and arranged in a ring on the outside of the outer support steel frame.

[0015] In summary, this application includes the following beneficial technical effects:

[0016] During the application of this technical solution, by setting a cap groove steel sheet, a cap groove aluminum sheet, and a cap sealing ring, it works in conjunction with the lithium battery body. During use, the cap groove steel sheet enhances structural strength, assists in conductivity, and works with the notch to buffer stress. The aluminum sheet, with its lightweight and conductive properties, works with the steel sheet and the sealing ring to ensure stable encapsulation and electrical connection. The sealing ring prevents leakage and adapts to the notch to ensure structural stability. In this way, the stability of the cap structure and the reliability of electrical connection are improved, which solves the problems of low assembly accuracy and large fit deviation caused by the combination of a single metal sheet and sealing component in traditional caps.

[0017] During the application of this technical solution, by designing an elastic protective shell, an explosion-extending deformation reserved groove, and a supporting outer group, the elastic protective shell undergoes physical deformation when the internal pressure of the battery rises sharply. The explosion-extending deformation reserved groove provides space for deformation. In conjunction with the inner and outer buffer spring frames to absorb pressure, the supporting outer group reinforces the overall structure from the outside. Thus, the explosion-proof effect of buffering pressure through physical deformation and preventing shell rupture is achieved, solving the problem that the traditional cap structure is not strong enough and lacks buffer design, making it easy to rupture under pressure.

[0018] During the application of this technical solution, by setting up a fusible connection component and a flame-retardant fluid, the fusible structure is triggered to connect when the battery is at high temperature. The flame-retardant fluid chemically interacts with the substances inside the battery to suppress the generation of combustible gases by cooling, isolating oxygen, and interrupting the combustion chain. At the same time, combined with the physical deformation of the elastic protective shell, the pressure rise is slowed down, thereby achieving a fire extinguishing effect of chemical inhibition and physical protection. This solves the problem that traditional caps lack an effective fire extinguishing mechanism and cannot prevent the spread of combustion. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure in Embodiment 1 of this application;

[0020] Figure 2 This is a schematic diagram of the split state structure in Embodiment 1 of this application;

[0021] Figure 3 This is a schematic diagram of the overall structure in Embodiment 2 of this application;

[0022] Figure 4 This is a schematic diagram of the structure of the elastic protective shell in the explosive deformation and expansion state in Embodiment 2 of this application;

[0023] Figure 5 This is a schematic diagram of the overall structure of the external support assembly in the embodiments of this application;

[0024] Figure 6 This is a schematic diagram of the top view of the support outer group structure in the embodiments of this application;

[0025] Figure 7 This is a schematic diagram of the protective shell in a disassembled state in an embodiment of this application;

[0026] Figure 8 This is a schematic diagram of the internal structure of the protective shell in an embodiment of this application.

[0027] Reference numerals: 1. Battery body; 2. Battery casing; 21. Elastic protective shell; 22. Fusible connection assembly; 221. Annular groove; 222. Sealing ring; 223. Fusible connection assembly; 2231. Connecting groove; 2232. Fusible sealing plug; 23. Cavity; 24. Supporting outer assembly; 241. Outer supporting steel frame; 242. Top reinforcing ring; 243. Bottom reinforcing circular plate; 244. Explosion extension deformation reserved groove; 25. Outer buffer spring frame; 26. Inner buffer spring frame; 3. Cap grooved steel sheet; 4. PCB board; 5. Lithium battery positive electrode connecting steel sheet; 6. Lithium battery positive electrode connecting aluminum sheet; 7. Lithium battery negative electrode sheet; 8. Lithium battery negative electrode connecting aluminum sheet; 9. Battery positive electrode connecting pin; 10. Lithium battery positive electrode body; 11. Cap sealing ring. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0029] Example 1

[0030] This application discloses a lithium battery structure with a notched composite cap. For example... Figure 1-8As shown, the battery includes a battery body 1, a battery casing 2 fixedly mounted on the outer surface of the battery body 1, a cap groove steel plate 3 fixedly connected to the top of the battery body 1, a PCB board 4 fixedly connected to the bottom of the cap groove steel plate 3, a lithium battery positive electrode connecting steel plate 5 fixedly connected to the bottom of the PCB board 4, a lithium battery positive electrode connecting aluminum plate 6 fixedly connected to the bottom of the lithium battery positive electrode connecting steel plate 5, a lithium battery negative electrode plate 7 fixedly connected to the outer side of the top of the cap groove steel plate 3, and a lithium battery negative electrode connecting aluminum plate 8 fixedly connected to the outer side of the top of the battery body 1. The lithium battery negative electrode plate 7 and the lithium battery negative electrode connecting aluminum plate 8 are electrically connected. The positive electrode connecting steel sheet 5 and the positive electrode connecting aluminum sheet 6 of the lithium battery are electrically connected. A positive electrode connecting pin 9 is fixedly connected to one side of the bottom of the cap groove steel sheet 3. The positive electrode body 10 of the lithium battery is fixedly connected to the middle of the top of the cap groove steel sheet 3. The bottom of the positive electrode body 10 and the positive electrode connecting steel sheet 5 are electrically connected. During application, the battery body 1 serves as the core to provide electrical energy, and the battery shell 2 on its outer surface provides protection. The cap groove steel sheet 3 on the top of the battery body 1 enhances the overall structural strength, assists in conductivity, and improves structural stability by buffering stress through the notch design. The PCB is connected to the bottom of the cap groove steel sheet 3. The PCB board plays a role in circuit control. The lithium battery positive terminal connecting steel plate 5 at the bottom of the PCB board is electrically connected to the lithium battery positive terminal connecting aluminum plate 6 at the bottom, forming a positive conductive path and reducing the problem of poor contact. The lithium battery negative terminal plate 7 on the outer side of the top of the cap groove steel plate 3 is electrically connected to the lithium battery negative terminal connecting aluminum plate 8 on the outer side of the top of the battery body 1, forming a negative conductive path and ensuring smooth current transmission. The battery positive terminal connecting pin 9 on one side of the bottom of the cap groove steel plate 3 is used for external circuit connection. The bottom of the lithium battery positive terminal body 10 in the middle of the top is electrically connected to the lithium battery positive terminal connecting steel plate 5 to realize power output. The coordinated work of each component not only ensures the reliability of electrical connection, but also improves the assembly accuracy through structural design, solving the problem of large misalignment of traditional caps.

[0031] Please refer to Figures 1-2The battery body 1 and battery casing 2 are cylindrical in shape, with rounded corners on both sides. The battery body 1 houses a BMS management module. A cap sealing ring 11, made of methyl vinyl silicone rubber, is fixedly connected to the bottom of the cap groove steel sheet 3. The cap sealing ring 11 is fitted and sealed to the outside of the bottom of the cap groove steel sheet 3. When this concave composite cap lithium battery structure is in operation, the cylindrical battery body 1 and battery casing 2 with rounded corners reduce the risk of impact damage during use and improve safety. The BMS module inside the battery body 1... The management module monitors the battery status in real time, enabling precise control of charging and discharging, and enhancing the stability of battery use. The cap groove steel sheet 3 at the top of the battery body 1 is fixed with a cap sealing ring 11 made of methyl vinyl silicone rubber, which is fitted and sealed on the outside of its bottom to effectively prevent electrolyte leakage and ensure sealing reliability. This solves the problem of poor sealing in traditional structures. All components work together: the battery body 1 provides power, the outer shell provides protection, and the cap and related components ensure stable electrical connections. The overall structure, through shape design, sealing rings, and BMS management, improves the safety, sealing, and stability of the battery.

[0032] Example 2

[0033] Please refer to Figures 5-6 The outer support assembly 24 includes an outer support steel frame 241, which is fixedly connected to the outside of the elastic protective shell 21. A top reinforcing ring 242 is fixedly connected to the top of the outer support steel frame 241 and is fitted onto the outside of the cap groove steel plate 3. A bottom reinforcing circular plate 243 is fixedly installed at the bottom of the outer support steel frame 241, covering the bottom of the battery body 1. Explosion-induced deformation pre-reserved grooves 244 are evenly spaced and arranged in a ring on the outside of the outer support steel frame 241. During application, the outer support steel frame 241 of the outer support assembly 24 is fixedly connected to the outside of the elastic protective shell 21, providing stable support for the overall structure. The top reinforcing ring 242 at the top of the outer support steel frame 241 is fitted onto the outside of the cap groove steel plate 3. The outer side of the channel steel sheet 3 enhances the structural strength of the connection between the cap and the battery body 1, reducing the possibility of damage to this part due to excessive force. The bottom reinforcing circular plate 243 of the outer support steel frame 241 covers the bottom of the battery body 1, improving the load-bearing capacity of the bottom of the battery and better coping with the pressure on the bottom. The explosion extension deformation reserved grooves 244 arranged in a ring at equal intervals on the outer side of the outer support steel frame 241 provide sufficient extension space for the elastic protective shell 21 when the internal pressure of the battery increases suddenly, causing it to deform, thus preventing the shell from cracking due to excessive deformation. These structures work together to further improve the overall structural stability and impact resistance of the battery, solving the problem that the traditional battery shell 2 is easily damaged when subjected to uneven force or excessive pressure.

[0034] Please refer to Figures 1-4 and Figures 7-8 The elastic protective shell 21 is made of elastic metal, including nanostructured copper-tantalum-lithium alloy, high-elasticity titanium alloy, high-elasticity aluminum alloy, pure aluminum, 3J1 high-elasticity alloy, beryllium bronze, and nickel-based alloy. An outer buffer spring frame 25 is fixedly connected to the outer side of the cavity 23, and an inner buffer spring frame 26 is fixedly installed on the inner side of the cavity 23. The inner buffer spring frame 26 and the outer buffer spring frame 25 are fixedly connected to each other. In specific applications, the elastic protective shell 21 can be made of nanostructured copper-tantalum-lithium alloy, high-elasticity titanium alloy, high-elasticity aluminum alloy, pure aluminum, 3J1 high-elasticity alloy, beryllium bronze, or nickel-based alloy. These materials provide good elasticity and structural strength to the shell. The outer side of the internal cavity 23 is fixedly connected to the outer buffer spring frame 25, and the inner side is fixedly installed with the inner buffer spring frame 26. The spring frame 26 and the outer buffer spring frame 25 are fixedly connected to each other. During operation, the elastic protective shell 21 can play a preliminary buffering role against external forces such as external impacts due to the elastic properties of its own material. When subjected to greater pressure, the inner and outer buffer spring frames 25 connected to each other in the cavity 23 will further deform to absorb and disperse the pressure, forming a multiple buffering mechanism in conjunction with the elastic protective shell 21. This design enhances the impact resistance of the battery shell 2, improves the protection effect of the battery body 1, solves the problem of insufficient buffering performance of traditional shells, and improves the structural stability of the battery during use. During specific applications, the above materials can be flexibly selected according to the application environment and cost.

[0035] Please refer to Figures 1-4 and Figures 7-8The battery casing 2 includes an elastic protective shell 21 and a fusible connection assembly 22. The elastic protective shell 21 is fixedly installed on the outside of the battery body 1. A cavity 23 is opened inside the elastic protective shell 21, and the cavity 23 is filled with flame-retardant fluid. A support assembly 24 is fixedly installed on the outside of the elastic protective shell 21. The fusible connection assembly 22 includes annular grooves 221, which are linearly arranged at equal intervals on the outer surface of the battery body 1. The inner side of the annular grooves 221 is connected to the inside of the battery body 1. A sealing ring 222 is fixedly installed inside each of the annular grooves 221. Fusible connection assemblies 223 are provided at equal intervals on the outer surface of the sealing rings 222. The fusible connection assemblies 223 include connecting grooves 2231, which are arranged in a ring at equal intervals on the outer surface of the sealing rings 222. The inner side of the connecting grooves 2231 is connected to the inside of the battery body 1. The internal connection of the connecting groove 2231 is fixedly connected to a fusible sealing plug 2232. The fusible sealing plug 2232 is made of Wood's alloy and has a maximum temperature resistance of 70 degrees Celsius. During application, the elastic protective shell 21 is fixed to the outside of the battery shell 2. The flame-retardant fluid filled in the internal cavity 23 can be a phosphate ester such as trimethyl phosphate, a solid material such as aluminum hydroxide ultrafine powder, or a water-based flame-retardant emulsion, which can play a role under specific conditions. The outer support assembly 24 can enhance the overall stability of the shell. In the fusible connecting assembly 22, the annular grooves 221 are equally spaced on the outer surface of the battery body 1 and communicate with the inside. The outer surface of the internal sealing ring 222 has equally spaced fusible connecting groups 223. The connecting grooves 2231 of the fusible connecting group 223 are connected to the inside of the battery body 1. The internal fusible sealing plug 2232 is made of Wood's alloy and has a temperature resistance of 70 degrees Celsius. The temperature reaches 70 degrees Celsius, which acts as a seal. When the internal temperature of the battery rises to 70 degrees Celsius, the fusible sealing plug 2232 melts, and the connecting groove 2231 opens, forming a channel between the annular groove 221 and the inside of the battery body 1 and the cavity 23. At this time, the flame-retardant fluid in the cavity 23 acts on the inside of the battery through the channel: phosphate esters can dilute flammable components and decompose to generate free radicals to interrupt the combustion chain; aluminum hydroxide ultrafine powder decomposes at high temperature, absorbs heat, and forms a flame-retardant film; water-based flame-retardant emulsion evaporates water, absorbs heat, and powder assists in forming a protective layer. These effects effectively inhibit the generation of flammable gases and slow down the temperature rise. The reinforced outer assembly 24, together with the elastic protective shell 21, enhances the structural strength, improves the battery's ability to cope with abnormal conditions, solves the problem of traditional shells lacking targeted protection, and enhances safety.

[0036] The implementation principle of the lithium battery structure with a notched composite cap in this application embodiment is as follows: During the application of this battery, its main body 1 serves as the energy storage core of the entire structure, continuously providing electrical energy and forming a close collaborative working relationship with the cap-related components. The outer battery shell 2 provides comprehensive protection and stable support from the outside. The cap recessed steel sheet 3, as the core structure of the composite cap, enhances the overall structural strength and assists in conductivity while effectively buffering stress through its notched design. The cap recessed aluminum sheet connected to its bottom, with its lightweight and conductive properties, works together with the steel sheet and the cap sealing ring 11 to ensure the tightness of the encapsulation and the stability of the electrical connection. The cap sealing ring 11 focuses on sealing and leak prevention, further ensuring the stability of the overall structure through precise adaptation with the notch. This structure has a built-in lithium battery protection function, namely BMS management, which can realize the charging and discharging control of individual cells. It is mainly used in the field of battery packs, compared with the traditional PCBA that uses cells plus external lithium protection. The innovation of this structure lies in its significant simplification of the overall structure and processing flow, while adopting a standard appearance design, ultimately forming a finished battery with multiple protection functions such as overcharge, over-discharge, overcurrent, and short circuit. The lithium battery positive electrode connecting steel sheet 5 and lithium battery positive electrode connecting aluminum sheet 6 work together to build an electrical connection channel between the battery positive electrode and the external circuit. The lithium battery negative electrode sheet 7 and lithium battery negative electrode connecting aluminum sheet 8 complete the electrical connection of the negative electrode. This series of connection structures, with the help of precise assembly design, not only greatly reduces the contact problems caused by component mismatch, but also significantly improves the overall assembly accuracy of the battery. The battery positive electrode connecting pin 9 is specifically used for docking the external circuit with the battery positive electrode. The lithium battery positive electrode body 10 serves as the positive electrode output terminal, and achieves effective energy output through electrical connection with the lithium battery positive electrode connecting steel sheet 5. The PCB board at the bottom of the cap groove steel sheet 3 undertakes the circuit control and signal transmission tasks, thereby ensuring the stability and order of current output.

[0037] The elastic protective shell 21 of the battery casing 2 is made of materials such as beryllium bronze, 301 stainless steel, and 65Mn spring steel. The excellent elasticity and ductility of these materials allow for adaptive deformation when abnormal pressure occurs inside the battery, providing ample buffer space for potential explosive impacts. Simultaneously, its structural strength is sufficient to withstand external collisions and compression during daily use, thus providing stable protection for the battery body 1. During normal battery operation, the battery body 1 stores and releases electrical energy through continuous internal electrochemical reactions. The cap sealing ring 11, made of methyl vinyl silicone rubber, is tightly fitted onto the bottom outer side of the cap groove steel sheet 3, effectively preventing electrolyte penetration and enhancing the battery's sealing performance. This prevents electrolyte leakage from adversely affecting battery performance and the surrounding environment. When abnormal conditions occur inside the battery, such as internal short circuits, overcharging, or over-discharging, the BMS management module will monitor key parameters such as battery voltage, current, and temperature in real time. If the internal battery temperature rises and reaches the threshold for fusion-breaking sealing plug 2232 in the fusion-connection assembly 22, the module will initiate a fusion-breaking process. When the temperature reaches a certain Celsius, the fusible seal plug 2232 made of Wood alloy will melt, making the inner side of the annular groove 221 connected to the inside of the battery body 1. At this time, the flame-retardant fluid filled in the cavity 23 inside the elastic protective shell 21 begins to play its role. Since the fusible seal plug 2232 inside the connecting groove 2231 has been melted, the flame-retardant fluid can enter the inside of the battery body 1 through the connecting groove 2231. When the temperature rises rapidly and the internal pressure of the battery body 1 increases sharply, the electrolyte material inside the battery will enter the cavity 23 while the connecting groove 2231 is connected. At this time, the flame-retardant fluid can assist in flame-retardant work.

[0038] In practical applications, flame-retardant fluids can utilize phosphate esters such as trimethyl phosphate and triethyl phosphate, or solid materials such as ultrafine aluminum hydroxide powder and ammonium dihydrogen phosphate powder. Liquid materials such as water-based flame-retardant emulsions can also be selected based on specific needs. When these flame-retardant fluids come into contact with the materials inside the battery, they react with the electrolyte at high temperatures: If phosphate esters are used, the flammability of the electrolyte can be reduced, interrupting the combustion chain; if ultrafine aluminum hydroxide powder is used, it can decompose at high temperatures and absorb heat, forming a flame-retardant film covering the electrode surface; the water in water-based flame-retardant emulsions evaporates and absorbs heat to achieve cooling, while the powder components assist in the formation of… The protective layer, through these functions, can effectively suppress the generation of flammable gases inside the battery and slow down the rate of temperature rise. In specific applications, its fire extinguishing and explosion-proof principle is as follows: Phosphate ester flame-retardant fluids are inherently non-flammable. When mixed with the high-temperature electrolyte inside the battery, they dilute the concentration of flammable components and reduce the overall flammability of the electrolyte. At the same time, under high temperature, phosphate esters decompose to produce phosphate ester free radicals. These free radicals can quickly capture active free radicals such as hydroxyl radicals and hydrogen radicals generated in the combustion reaction, interrupt the transmission of the combustion chain, and prevent the combustion reaction from continuing, thereby reducing heat release and the generation of flammable gases.

[0039] When ultrafine aluminum hydroxide powder, a flame-retardant fluid, comes into contact with the interior of a high-temperature battery, it undergoes an endothermic decomposition reaction, releasing water of crystallization and absorbing a large amount of heat. This directly lowers the internal temperature of the battery, slowing down the spread of thermal runaway. The resulting alumina powder has excellent coverage, forming a dense flame-retardant film on the electrode surface, isolating the electrode from contact with the electrolyte and oxygen, preventing further oxidation of the electrode material, and reducing the source of gas generation at the root. When ammonium dihydrogen phosphate powder is used as a flame-retardant fluid, it decomposes at high temperatures to produce phosphoric acid and ammonia. Phosphoric acid can form a glassy flame-retardant coating on the electrode surface, physically blocking heat and mass exchange. Ammonia, as an inert gas, dilutes the oxygen concentration inside the battery, reducing the combustion-supporting effect of oxygen. Simultaneously, the release of ammonia also absorbs some heat, aiding in cooling. The water in the water-based flame-retardant emulsion, upon contact with high temperatures... At low temperatures, it will rapidly evaporate into water vapor. This process requires the absorption of a large amount of latent heat, which can quickly reduce the internal temperature of the battery, making the temperature lower than the decomposition threshold of the electrolyte and the ignition point of the combustible gas. The ultrafine flame-retardant powder in the emulsion, such as aluminum hydroxide, will be evenly distributed on the electrode surface as the water evaporates, forming a continuous flame-retardant coating layer, which further enhances the oxygen and heat insulation effects. At the same time, the presence of surfactants can enhance the wettability of the emulsion on the electrode surface, ensuring that the flame-retardant components are in full contact with the high-temperature area. Through the synergistic effects of the above-mentioned cooling, oxygen isolation, interruption of the combustion chain, and formation of physical barriers, these flame-retardant fluids gradually weaken the thermal runaway reaction inside the battery, reduce the amount of combustible gas generated and the pressure increase, and buy time for structural protection measures such as deformation buffering of the elastic protective shell 21 and space release of the explosion extension deformation reserved groove 244, ultimately reducing the risk of battery shell rupture and explosion.

[0040] Meanwhile, the elastic protective shell 21 deforms under internal pressure. The outer buffer spring frame 25 and inner buffer spring frame 26 work together to further absorb and buffer the pressure, reducing the impact on the battery casing 2. The outer support steel frame 241 supporting the outer assembly 24 reinforces the battery from the outside. The top reinforcing ring 242 is fitted onto the outside of the cap groove steel plate 3, enhancing the structural strength of the connection between the cap and the battery body 1. The bottom reinforcing circular plate 243 covers the bottom of the battery body 1, improving the load-bearing capacity of the battery bottom and preventing explosions at the top and bottom of the battery. The explosion extension deformation pre-reserved groove 244 provides ample space for the deformation of the elastic protective shell 21. Under high pressure, the elastic protective shell 21 can expand through this groove. The pre-deformed groove reduces internal pressure in the battery body 1, preventing the casing from cracking due to excessive deformation. The battery body 1 and battery casing 2 are cylindrical in shape, with rounded corners. This design reduces the risk of damage when the battery bumps into other objects during use and lowers the possibility of internal structural damage due to external impacts. Through the synergistic effect of the components, this concave composite cap lithium battery structure effectively solves the problems of low assembly precision, poor sealing reliability, weak safety protection, and lack of explosion protection in traditional lithium battery caps while ensuring normal power output. It comprehensively improves the safety, reliability, and lifespan of lithium batteries and is suitable for multiple fields such as portable electronic devices, new energy vehicles, and energy storage systems.

[0041] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A lithium battery structure with a notched composite cap, characterized in that; The battery includes a battery body (1), a battery casing (2) is fixedly mounted on the outer surface of the battery body (1), a cap groove steel sheet (3) is fixedly connected to the top of the battery body (1), a PCB board (4) is fixedly connected to the bottom of the cap groove steel sheet (3), a lithium battery positive electrode connection steel sheet (5) is fixedly connected to the bottom of the PCB board (4), a lithium battery positive electrode connection aluminum sheet (6) is fixedly connected to the bottom of the lithium battery positive electrode connection steel sheet (5), and a lithium battery negative electrode sheet (7) is fixedly connected to the outer side of the top of the cap groove steel sheet (3). A lithium battery negative electrode connecting aluminum sheet (8) is fixedly connected to the top outer side of the body (1). The lithium battery negative electrode sheet (7) and the lithium battery negative electrode connecting aluminum sheet (8) are electrically connected. The lithium battery positive electrode connecting steel sheet (5) and the lithium battery positive electrode connecting aluminum sheet (6) are electrically connected. A battery positive electrode connecting pin (9) is fixedly connected to one side of the bottom of the cap groove steel sheet (3). A lithium battery positive electrode body (10) is fixedly connected to the top middle of the cap groove steel sheet (3). The bottom of the lithium battery positive electrode body (10) and the lithium battery positive electrode connecting steel sheet (5) are electrically connected. The battery casing (2) includes an elastic protective casing (21) and a fusible connection assembly (22). The elastic protective casing (21) is fixedly installed on the outside of the battery body (1). A cavity (23) is opened inside the elastic protective casing (21). The cavity (23) is filled with flame-retardant fluid. A support outer assembly (24) is fixedly installed on the outside of the elastic protective casing (21). The fusible connection assembly (22) includes an annular groove (221), which is linearly arranged at equal intervals on the outer surface of the battery body (1). The inner side of the annular groove (221) is connected to the inside of the battery body (1). A sealing ring (222) is fixedly installed inside the annular groove (221), and fusible connection groups (223) are provided at equal intervals on the outer surface of the sealing ring (222).

2. The lithium battery structure with a notched composite cap according to claim 1, characterized in that: The battery body (1) and battery shell (2) are cylindrical in shape, and the outer corners of the battery body (1) and battery shell (2) are rounded.

3. The lithium battery structure with a notched composite cap according to claim 2, characterized in that: The battery body (1) is equipped with a BMS management module inside, and the bottom of the cap groove steel sheet (3) is fixedly connected with a cap sealing ring (11).

4. The lithium battery structure with a notched composite cap according to claim 3, characterized in that: The cap sealing ring (11) is made of methyl vinyl silicone rubber and is fitted and sealed on the bottom outer side of the cap groove steel sheet (3).

5. The lithium battery structure with a notched composite cap according to claim 4, characterized in that: The fusion assembly (223) includes a connecting groove (2231), which is arranged in a ring at equal intervals on the outer surface of the sealing ring (222). The inner side of the connecting groove (2231) is connected to the inside of the battery body (1). A fusion sealing plug (2232) is fixedly connected inside the connecting groove (2231). The fusion sealing plug (2232) is made of Wood alloy and its maximum temperature resistance is 70 degrees Celsius.

6. The lithium battery structure with a notched composite cap according to claim 5, characterized in that: An outer buffer spring frame (25) is fixedly connected to the inner side of the cavity (23), and an inner buffer spring frame (26) is fixedly installed on the inner side of the cavity (23). The inner buffer spring frame (26) and the outer buffer spring frame (25) are fixedly connected to each other.

7. The lithium battery structure with a notched composite cap according to claim 6, characterized in that: The elastic protective shell (21) is made of elastic metal, including nanostructured copper-tantalum-lithium alloy, high-elasticity titanium alloy, high-elasticity aluminum alloy, pure aluminum, 3J1 high-elasticity alloy, beryllium bronze, and nickel-based alloy.

8. The lithium battery structure with a notched composite cap according to claim 7, characterized in that: The outer support assembly (24) includes an outer support steel frame (241), which is fixedly connected to the outside of the elastic protective shell (21). A top reinforcing ring (242) is fixedly connected to the top of the outer support steel frame (241), and the top reinforcing ring (242) is sleeved on the outside of the cap groove steel sheet (3). A bottom reinforcing circular plate (243) is fixedly installed at the bottom of the outer support steel frame (241), and the bottom reinforcing circular plate (243) covers the bottom of the battery body (1). Explosion extension deformation reserved grooves (244) are evenly spaced and arranged in a ring on the outside of the outer support steel frame (241).

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