Battery early warning device and method based on double anti-explosion valve structure

Abstract

The invention provides a battery early warning device and method based on a double anti-explosion valve structure, the battery early warning device comprises a positive electrode cover plate, the positive electrode cover plate is provided with a plurality of exhaust holes, the lower part of the positive electrode cover plate is connected with an exhaust anti-explosion sheet, the exhaust anti-explosion sheet is provided with an exhaust anti-explosion weak structure, an early warning anti-explosion structure is installed below the exhaust anti-explosion sheet, and the early warning anti-explosion structure is connected with the exhaust anti-explosion sheet. The positive electrode cover plate and the exhaust explosion-proof sheet are respectively connected with the early-warning explosion-proof structure, the lower part of the early-warning explosion-proof structure is connected with a connecting aluminum sheet through an insulating rubber ring, the connecting aluminum sheet is provided with a plurality of diversion holes, and the early-warning explosion-proof structure, the insulating rubber ring and the connecting aluminum sheet are respectively connected with an insulating sealing ring. The problem that an existing battery safety valve is subjected to passive pressure relief and lacks thermal runaway early warning capacity is solved, the battery double-safety-valve thermal runaway early warning technology with the graded pressure relief and dynamic early warning functions is adopted, the safety perception and prevention disposal time of the battery in a thermal runaway scene is prolonged, and therefore the thermal runaway risk of the power battery is reduced.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically relating to a battery early warning device and method based on a dual explosion-proof valve structure. Background Technology

[0002] With the surge in demand for lithium-ion batteries from new energy vehicles, energy storage power stations, and other fields, battery safety has become a core bottleneck restricting the industry's development. Under abnormal operating conditions such as overcharging, short circuits, high temperatures, and mechanical impacts, lithium-ion batteries are prone to chain reactions, including electrolyte decomposition, oxygen release from the positive electrode material, and reaction between the negative electrode and the electrolyte. These reactions are accompanied by the accumulation of large amounts of heat and combustible gases (such as CO and CH4), ultimately triggering thermal runaway.

[0003] To mitigate the aforementioned problems, existing technologies generally employ a single explosion-proof valve structure: when the internal pressure of the battery reaches a preset threshold, the explosion-proof valve's rupture disc or opening mechanism activates, releasing gas pressure. However, this solution has significant limitations: firstly, a single explosion-proof valve only has a passive pressure relief function and lacks early warning capability—when the explosion-proof valve opens, the battery has already entered the later stages of thermal runaway, at which point the heat and gas release rate is rapid, making external intervention measures such as fire extinguishing and power cut-off ineffective; secondly, low-temperature environments, battery aging, and other issues can lead to a decrease in the threshold response accuracy of the single explosion-proof valve, making it prone to situations where pressure relief occurs before thermal runaway, resulting in battery performance degradation or failure to activate even when the pressure exceeds the threshold, thus exacerbating the risk of explosion.

[0004] In summary, current battery safety protection technologies struggle to achieve synergistic effects between "explosion-proof pressure relief" and "thermal runaway early warning," and suffer from issues such as delayed warnings and low reliability. Therefore, there is an urgent need for an integrated, highly reliable structural design that can efficiently relieve pressure while simultaneously triggering early warning of thermal runaway, buying time for subsequent interventions and fundamentally reducing the incidence of battery safety accidents. Summary of the Invention

[0005] The purpose of this invention is to provide a battery early warning device and method based on a dual explosion-proof valve structure, which improves the safety perception and prevention and handling time of batteries in thermal runaway scenarios, thereby reducing the risk of thermal runaway of power batteries and reducing personal injury and property loss.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A battery warning device based on a dual explosion-proof valve structure includes: a positive electrode cover plate with multiple vent holes; a lower part of the positive electrode cover plate connected to an explosion-proof venting sheet; the explosion-proof venting sheet having a weak explosion-proof venting structure; an early warning explosion-proof structure installed below the explosion-proof venting sheet; the positive electrode cover plate and the explosion-proof venting sheet being connected to the early warning explosion-proof structure respectively; the early warning explosion-proof structure being connected to a connecting aluminum sheet via an insulating rubber ring; the connecting aluminum sheet having multiple flow guiding holes; and the early warning explosion-proof structure, the insulating rubber ring, and the connecting aluminum sheet being connected to an insulating sealing ring respectively.

[0008] Furthermore, a pressure sensor is installed in the sealed cavity formed by the exhaust explosion-proof plate and the early warning explosion-proof structure.

[0009] Furthermore, the early warning explosion-proof structure is an early warning explosion-proof sheet with an early warning explosion-proof weak structure, and a pressure sensor is installed on the early warning explosion-proof sheet.

[0010] Furthermore, the warning explosion-proof structure is a warning explosion-proof sheet with a thin film installed at the center position. The thin film is fixed below the working end of the needle, and the needle is installed below the exhaust explosion-proof sheet.

[0011] Furthermore, the film is an ultra-thin insulating film made of polyimide polyester.

[0012] Furthermore, the exhaust explosion-proof sheet is made of aluminum alloy with a thickness of 0.3 mm.

[0013] Furthermore, the connecting aluminum sheet is welded to the battery tab, and the connecting aluminum sheet has uniformly distributed annular flow guide holes.

[0014] Furthermore, the weak structure for exhaust explosion protection or the weak structure for early warning explosion protection is a grooved area with a preset rupture pressure formed by a stamping process, wherein the preset rupture pressure is lower than the rupture pressure of the early warning explosion protection sheet.

[0015] Furthermore, the insulating sealing ring is interference-fitted at the connection between the positive electrode cover and the battery casing.

[0016] The present invention may also include:

[0017] A battery early warning method using the aforementioned battery early warning device: When battery thermal runaway occurs, initially, the battery cell generates a small amount of gas due to the reaction. Under internal pressure, the gas converges along the guide hole and preferentially acts on the surface of the early warning explosion-proof structure, causing the pressure on it to gradually increase. A pressure sensor monitors this change and transmits a signal to the battery management system. As thermal runaway progresses, the battery cell temperature rises, leading to electrolyte decomposition and increased gas generation. The pressure on the early warning explosion-proof structure rises rapidly. When the pressure reaches the rupture threshold, the weak structure of the early warning explosion-proof structure breaks, or the film is punctured by a needle due to gas generated in the early stage of thermal runaway. The entire early warning explosion-proof structure bulges outward, forming a venting gap.

[0018] The moment the explosion-proof structure breaks, the pressure sensor captures the characteristic signal of the sudden pressure change and transmits it to the battery management system. The system then determines that the warning valve has been triggered, quickly initiates an emergency response, cuts off the charging and discharging circuit, improves the efficiency of the liquid cooling system, and sends an audible and visual alarm to the terminal. Through early intervention, the risk of battery explosion and heat spread is effectively reduced.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention sets a pressure gradient between the early warning explosion-proof plate and the exhaust explosion-proof plate, allowing the early warning explosion-proof plate to trigger an early signal in the initial stage of thermal runaway, thus buying critical time for intervention measures such as cooling and power cut-off. To meet the differentiated needs of different application scenarios, the opening pressure threshold can be changed by adjusting the stamping depth of the weak structure of the early warning explosion-proof plate, and the triggering sensitivity can be adjusted by replacing the film with films of different thicknesses and materials. Attached Figure Description

[0021] Appendix Figure 1 This is a schematic diagram of the battery early warning device based on the dual explosion-proof valve structure of the present invention;

[0022] Appendix Figure 2 This is a schematic diagram of the structure of the membrane battery early warning device based on the dual explosion-proof valve structure of the present invention;

[0023] Appendix Figure 3 This is a flowchart of the multi-dimensional protection response after the early warning signal of battery thermal runaway is triggered according to the present invention.

[0024] Explanation of reference numerals in the attached diagram: 1. Positive electrode cover plate, 2. Vent hole, 3. Vent explosion-proof sheet, 4. Early warning explosion-proof structure, 5. Insulating sealing ring, 6. Pressure sensor, 7. Vent explosion-proof weak structure, 8. Early warning explosion-proof weak structure, 9. Insulating small rubber ring, 10. Connecting aluminum sheet, 11. Guide hole, 12. Needle, 13. Thin film. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] This invention provides a battery warning device based on a dual explosion-proof valve structure, as shown in the attached figure. Figure 1 , 2 As shown, it includes: a positive electrode cover plate 1, which has multiple vent holes 2; the lower part of the positive electrode cover plate 1 is connected to a vent explosion-proof sheet 3; the vent explosion-proof sheet 3 has a weak vent explosion-proof structure 7; a warning explosion-proof structure 4 is installed below the vent explosion-proof sheet 3; the positive electrode cover plate 1 and the vent explosion-proof sheet 3 are respectively connected to the warning explosion-proof structure 4; the lower part of the warning explosion-proof structure 4 is connected to a connecting aluminum sheet 10 through an insulating rubber ring 9; the connecting aluminum sheet 10 has multiple guide holes 11; and the warning explosion-proof structure 4, the insulating rubber ring 9, and the connecting aluminum sheet 10 are respectively connected to an insulating sealing ring 5.

[0027] In this embodiment, the positive electrode cover plate 1 is made of high-strength aluminum alloy and serves as the conductive carrier of the battery's positive electrode. The array of vent holes on the positive electrode cover plate 1 allows the high-pressure thermal runaway gas inside to form a directional venting channel and be quickly released to the outside of the battery through these holes in the event of thermal runaway of the power battery. This reduces the risk of battery explosion.

[0028] The exhaust explosion-proof sheet 3 is made of aluminum alloy sheet with a thickness of 0.3mm. It is connected to the positive electrode cover plate 1 by laser welding. An exhaust explosion-proof weak structure 7 is formed in a specific area by stamping process, that is, a grooved area with a preset rupture pressure. When the battery runs out of control internally, the weak structure will first undergo plastic rupture and instantly release a large amount of high-pressure gas. It is the key link for emergency pressure relief of battery thermal runaway.

[0029] In this embodiment, the first structure of the early warning explosion-proof structure 4 can be made of aluminum material with the same material as the exhaust explosion-proof sheet but with a thinner thickness. The early warning explosion-proof weak structure 8 is also processed by stamping process. Its preset rupture pressure is lower than that of the exhaust explosion-proof sheet. In the early stage of thermal runaway, when the internal pressure of the battery rises slowly, the weak structure of the early warning explosion-proof structure 4 will rupture first. The pressure sensor 6 triggered by mechanical deformation will buy critical time for thermal runaway intervention.

[0030] The second structure of the warning explosion-proof structure 4 can also be a thin film structure, which is a warning explosion-proof sheet with a thin film 13 installed at the center. The thin film 13 is an ultra-thin insulating film made of polyimide polyester. It is fixed below the action end of the needle 12 by an adhesive process. In the early stage of thermal runaway, the generated gas pushes the film to be punctured. The pressure sensor 6 monitors the sudden drop in pressure and transmits it to the battery management system to trigger an alarm.

[0031] Specifically, needle 12 is made of stainless steel and is laser-welded onto the exhaust explosion-proof sheet.

[0032] In this embodiment, the pressure sensor 6 is a miniature pressure sensing element that adopts the silicon-based piezoresistive principle. It is installed in a sealed cavity directly above the early warning explosion-proof sheet. It can detect changes in the pressure borne by the early warning explosion-proof sheet. In the early stage of thermal runaway, when the early warning explosion-proof sheet ruptures and the monitoring pressure drops sharply, it converts the pressure signal into an electrical signal and transmits it to the battery management system to achieve the purpose of early intervention in thermal runaway.

[0033] In this embodiment, both the insulating sealing ring 5 and the insulating rubber ring 9 are made of corrosion-resistant and high-temperature resistant rubber. They are installed at the connection between the positive electrode cover plate 1 and the battery casing and on the outer periphery of the connecting aluminum sheet 10 in an interference fit manner. The insulating sealing ring 5 isolates the electrical connection between the positive electrode cover plate and the metal casing to prevent the battery from short-circuiting.

[0034] In this embodiment, the connecting aluminum sheet 10 is connected to the battery tab by laser welding. When the battery is working normally, it is the main channel for power output. It has a ring of evenly distributed guide holes 11. In the event of thermal runaway, the guide holes guide the high-temperature gas and liquid electrolyte residue generated by the decomposition of the electrolyte to flow to the top explosion-proof area, so that the gas quickly converges to the explosion-proof sheet, ensuring that the explosion-proof sheet can sense the pressure and act in time.

[0035] This embodiment also provides a battery early warning method. The method uses the above-mentioned device. When thermal runaway of the battery occurs, the cell initially generates a small amount of gas due to the reaction. Under the action of internal pressure, the gas converges along the guide hole and preferentially acts on the surface of the early warning explosion-proof structure 4, causing the pressure on it to gradually increase. The pressure sensor 6 monitors this change and transmits a signal to the battery management system. As thermal runaway progresses, the cell temperature rises, causing the electrolyte to decompose and the amount of gas generated to increase. The pressure on the early warning explosion-proof structure 4 rises rapidly. When the pressure reaches the rupture threshold, the early warning explosion-proof weak structure 8 breaks, or the film 13 is punctured by the needle 12 due to the gas generated in the early stage of thermal runaway. The early warning explosion-proof structure 4 bulges outward as a whole, forming a venting gap.

[0036] The moment the explosion-proof structure 4 breaks, the pressure sensor 6 captures the characteristic signal of the sudden pressure change and transmits it to the battery management system. The system then determines that the warning valve has been triggered, quickly starts an emergency response, cuts off the charging and discharging circuit, improves the efficiency of the liquid cooling system, and sends an audible and visual alarm to the terminal. Through early intervention, the risk of battery explosion and heat spread is effectively reduced.

[0037] The following section discusses what happens when a battery experiences thermal runaway due to internal short circuits, overcharging, or other factors, in conjunction with the attached... Figure 3 The operation process is explained in detail:

[0038] In the initial stage, the internal temperature of the battery cell rises to 80-100℃, and the electrolyte undergoes preliminary decomposition, producing trace amounts of gases such as CH4 and CO. Driven by the internal pressure of the battery cell, the gases converge upward along the channel of the guide hole 11 and preferentially act on the inner surface of the early warning explosion-proof structure 4, causing the local pressure on the early warning explosion-proof structure 4 to slowly rise from the initial 0.1MPa. The pressure sensor 6 captures this pressure change in real time and transmits data to the battery management system at a frequency of 2Hz. When the pressure rises to 0.3MPa, the transmission frequency is automatically increased to 10Hz to mark the abnormal pressure increase signal.

[0039] Furthermore, when the cell temperature exceeds 100℃, the electrolyte decomposes violently, the amount of gas generated surges, and the pressure on the early warning explosion-proof structure 4 enters a rapid rising phase, increasing from 0.3MPa to 0.6MPa within 10 seconds, triggering the first-level early warning preparation; when the pressure reaches the preset rupture threshold of 0.6MPa for the weak structure 8 of the early warning explosion-proof sheet, the scored area first undergoes plastic deformation and completely breaks within 0.1 seconds, and the entire early warning explosion-proof structure 4 bulges outward to form a 2mm wide release gap.

[0040] Furthermore, at the moment the early warning explosion-proof structure 4 breaks, the pressure sensor 6 detects a sudden drop in local pressure. This "sudden rise-sudden fall" characteristic curve is transmitted to the battery management system and is determined to be the trigger of the early warning valve. After receiving the signal, the battery management system initiates an emergency response within 0.5 seconds: cuts off the main circuit charging and discharging current, increases the flow rate of the liquid cooling system, and sends an audible and visual alarm to the terminal to achieve early intervention in thermal runaway, effectively avoids battery explosion and large-scale thermal spread, and improves the battery safety protection level.

[0041] Furthermore, if cooling intervention fails to curb thermal runaway, the cell temperature exceeds 300°C, the positive electrode material decomposes to produce oxygen, which reacts violently with electrolyte vapor to generate a large amount of high-temperature gas. This gas rushes through the guide hole to the area of ​​the exhaust explosion-proof plate 3, causing the pressure on the exhaust explosion-proof plate 3 to rise rapidly, reaching the 1.2MPa rupture threshold and rupturing. The high-pressure gas is then ejected through the exhaust hole 2.

[0042] Furthermore, the warning explosion-proof sheet can employ a stamped weak structure of varying depths to better adapt to the activation pressure of the warning sheet in different scenarios. For example, in high-altitude, low-pressure environments, the gas inside the battery is more likely to expand and accumulate. To prevent the warning explosion-proof sheet from being falsely triggered due to low ambient pressure, a weak structure with a shallow stamping depth can be used, corresponding to a higher activation pressure threshold, ensuring that the warning is only triggered in the early stages of battery thermal runaway. In consumer electronics batteries operating at normal temperature and pressure (such as smartphone and laptop batteries), the sensitivity requirements for early warning of thermal runaway are even higher, requiring a rapid response even with a slight increase in pressure. In this case, a weak structure with a deep stamping depth can be used, lowering the activation pressure threshold and triggering the warning even during the stage of minute gas generation in the cell, giving users more time to react.

[0043] Furthermore, for scenarios like power batteries (such as electric vehicle battery packs) where the response speed to thermal runaway is extremely critical, pressure changes need to be detected within milliseconds. A diaphragm-type warning valve can be used, employing a thin, brittle polyimide film that can be punctured by a needle when the explosion-proof structure undergoes slight deformation. Combined with pressure sensor signals, this provides a sensitive warning, ensuring the battery management system quickly initiates cooling and power-off procedures.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery early warning device based on a dual explosion-proof valve structure, characterized in that, include: A positive electrode cover plate (1) has multiple vent holes (2). The lower part of the positive electrode cover plate (1) is connected to a vent explosion-proof sheet (3). The vent explosion-proof sheet (3) has a weak vent explosion-proof structure (7). A warning explosion-proof structure (4) is installed below the vent explosion-proof sheet (3). The positive electrode cover plate (1) and the vent explosion-proof sheet (3) are respectively connected to the warning explosion-proof structure (4). The lower part of the warning explosion-proof structure (4) is connected to the connecting aluminum sheet (10) through an insulating rubber ring (9). The connecting aluminum sheet (10) has multiple flow guide holes (11). The warning explosion-proof structure (4), the insulating rubber ring (9), and the connecting aluminum sheet (10) are respectively connected to an insulating sealing ring (5).

2. The battery early warning device based on a dual explosion-proof valve structure according to claim 1, characterized in that, A pressure sensor (6) is installed in the sealed cavity formed by the exhaust explosion-proof plate (3) and the early warning explosion-proof structure (4).

3. The battery early warning device based on a dual explosion-proof valve structure according to claim 2, characterized in that, The warning explosion-proof structure (4) is a warning explosion-proof sheet with a warning explosion-proof weak structure (8), and a pressure sensor (6) is installed on the warning explosion-proof sheet.

4. The battery early warning device based on a dual explosion-proof valve structure according to claim 2, characterized in that, The warning explosion-proof structure (4) is a warning explosion-proof sheet with a film (13) installed at the center. The film (13) is fixed below the working end of the needle (12), and the needle (12) is installed below the exhaust explosion-proof sheet (3).

5. The battery early warning device based on a dual explosion-proof valve structure according to claim 4, characterized in that, The film (13) is an ultra-thin insulating film made of polyimide polyester.

6. The battery early warning device based on a dual explosion-proof valve structure according to claim 5, characterized in that, The exhaust explosion-proof sheet (3) is made of aluminum alloy sheet with a thickness of 0.3 mm.

7. The battery early warning device based on a dual explosion-proof valve structure according to claim 6, characterized in that, The connecting aluminum sheet (10) is welded to the battery tab, and the connecting aluminum sheet (10) has a ring of uniformly distributed flow guide holes (11).

8. The battery early warning device based on a dual explosion-proof valve structure according to claim 7, characterized in that, The exhaust explosion-proof weak structure (7) or the early warning explosion-proof weak structure (8) is a grooved area with a preset rupture pressure formed by a stamping process. The preset rupture pressure is lower than the rupture pressure of the early warning explosion-proof sheet.

9. The battery early warning device based on a dual explosion-proof valve structure according to claim 8, characterized in that, The insulating sealing ring (5) is installed with an interference fit at the connection between the positive electrode cover plate and the battery casing.

10. A battery early warning method, characterized in that, Using the battery warning device according to any one of claims 1-9, when battery thermal runaway occurs, the cell initially generates a small amount of gas due to the reaction. Under the action of internal pressure, the gas converges along the guide hole and preferentially acts on the surface of the warning explosion-proof structure (4), causing the pressure on it to gradually increase. The pressure sensor (6) monitors this change and transmits a signal to the battery management system. As thermal runaway proceeds, the cell temperature rises, causing the electrolyte to decompose and the amount of gas generated to increase. The pressure on the warning explosion-proof structure (4) rises rapidly. When the pressure reaches the rupture threshold, the warning explosion-proof weak structure (8) breaks or the film (13) generates gas in the early stage of thermal runaway and is pushed to be punctured by the needle (12). The warning explosion-proof structure (4) bulges outward as a whole, forming a venting gap. The pressure sensor (6) captures the characteristic signal of the sudden pressure change when the early warning explosion-proof structure (4) breaks and transmits it to the battery management system. The system then determines that the early warning valve is triggered, quickly starts an emergency response, cuts off the charging and discharging circuit, improves the efficiency of the liquid cooling system, and sends an audible and visual alarm to the terminal. Through early intervention, the risk of battery explosion and heat spread is effectively reduced.

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