Active venting device for a high capacity battery

Abstract

The application discloses an active release device of a large-capacity battery, which comprises a pressure relief cavity connected with a battery cover plate, a driving assembly, a pressure relief membrane and a positioning pin, the core of the driving assembly is a memory spring, the upper end of the memory spring is connected with a conical cap provided with a breathable hole, the lower end of the memory spring is connected with a bottom cap fixed with the lower part of the pressure relief cavity, and the pressure relief membrane is located at the upper part of the pressure relief cavity. The active release device can be used in the state of short circuit, overcharge and overdischarge and abuse of the battery, when the internal temperature of the battery reaches the response temperature range of the driving device, the memory spring will be deformed and displaced, the conical cap is driven to pierce the pressure relief membrane, and the high-pressure mixed gas in the battery is released, so that the accurate pressure reduction at a specific temperature can be realized, the deformation and explosion of the battery shell are prevented, the thermal runaway of the battery is prevented, and the use safety of the battery is improved.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a venting structure for a large-capacity battery. Background Technology

[0002] Lithium-ion batteries use organic electrolytes. During battery operation, factors such as overcharging, over-discharging, heavy use, and short circuits can cause the internal temperature of the battery to rise. Data shows that when the internal temperature of the battery reaches 70°C, the electrolyte begins to slowly decompose. At 85°C, the decomposition rate accelerates, and further temperature increases produce a large amount of mixed gas, increasing the internal pressure of the battery. This can cause casing deformation, bulging, and in severe cases, explosions and fires.

[0003] Currently, explosion-proof devices are typically installed on the battery casing. Common explosion-proof devices include explosion-proof valves, explosion-proof membranes, explosion-proof needles, and explosion-proof grooves. Explosion-proof membranes are the most widely used method, involving a thin metal film laminated to the pressure relief port on the cover. This membrane can withstand a certain pressure; when the pressure exceeds its tolerance, it ruptures, releasing gas and reducing danger. However, due to varying manufacturing processes, the pressure relief accuracy of explosion-proof membranes is relatively poor. Similarly, adding grooves or grooves to the battery casing also presents challenges in controlling pressure relief accuracy. Some explosion-proof valves use explosion-proof needles with a conical needle-like head. However, this type of needle is easily punctured by external factors (such as impacts or pressure), affecting battery life.

[0004] Shape memory alloys (MMEs) possess excellent shape memory properties and good mechanical properties. When an MME is deformed under external force in its martensitic state, it recovers its original shape upon heating to the parent phase. Typically, the output displacement reaches 30-50% of the original length of the MME. Utilizing the specific temperature deformation characteristics of MMEs, they can be designed as driving components to open battery vents. This allows for precise pressure relief within a specific temperature range, thereby reducing safety risks during battery use. Summary of the Invention

[0005] To address the issue of precise and safe pressure relief in batteries, this application provides a pressure relief device with a simple structure and reliable operation. It employs a pressure relief driving component made of shape memory alloy, which can deform and displace within a specific temperature range to apply stress to the pressure relief diaphragm of the pressure relief port, thereby achieving precise and safe pressure relief.

[0006] An active discharge device for a large-capacity battery includes a pressure relief chamber, a drive assembly, a venting membrane, and a positioning pin. The core of the drive assembly is a memory spring. The upper end of the memory spring is connected to a conical cap, and the lower end is connected to a circular bottom cap. The conical cap has several vent holes, and the circumference of the folded edge of the circular bottom cap has several positioning holes. The surface of the bottom cap has several circular vent holes.

[0007] Furthermore, the drive assembly is located below the explosion diaphragm within the pressure relief chamber.

[0008] Furthermore, the vent holes on the conical cap are triangular and are evenly distributed along the surface of the cone.

[0009] Furthermore, the vertical distance between the top of the conical cap of the drive assembly and the explosion vent membrane is no more than 5 mm.

[0010] Furthermore, the pressure relief chamber is a cylindrical tube with a positioning ring on the body, and the positioning ring is welded to the connection hole of the battery cover.

[0011] Furthermore, the upper inner wall of the pressure relief chamber is provided with a circular recess, and the explosion relief membrane is welded to the circular recess.

[0012] Furthermore, the pressure relief chamber is located on a cylindrical body below the battery cover and is provided with positioning holes. The number and position of the positioning holes are the same as those of the positioning holes on the bottom cap of the drive device.

[0013] Furthermore, the bottom cap of the drive assembly is flush with the pressure relief chamber and fixed with a locating pin.

[0014] Furthermore, the bottom cap and the pressure relief chamber are fixed together by a locating pin.

[0015] Furthermore, the memory spring is made of CuZnAl memory alloy, and its operating temperature is 80-95℃.

[0016] Furthermore, the positioning pin is a rivet or bolt, made of stainless steel or aluminum.

[0017] Furthermore, the cap and pressure relief chamber are made of stainless steel or aluminum.

[0018] This application also provides a high-capacity battery, including the aforementioned active discharge device for the high-capacity battery.

[0019] This application uses a memory spring that can deform within a specific temperature range as a driving element. When the temperature of the memory spring reaches its deformation temperature, it can generate deformation displacement, driving the conical striker of the cap to apply stress to the explosion venting membrane, converting surface pressure into point pressure, reducing the difficulty of explosion venting, and at the same time achieving pressure venting within a precise temperature range, improving the reliability of explosion venting, preventing bulging deformation during battery use, preventing thermal runaway caused by the pressure venting port not opening in time, and improving the safety of battery use. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 Overall view of a discharge device for a large-capacity battery

[0022] Figure 2 Exploded view of a discharge device for a high-capacity battery

[0023] Figure 3 View of the drive unit

[0024] Figure 4 View of the explosion venting cavity

[0025] Figure 5 View of the battery cover Detailed Implementation

[0026] The embodiments of this application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement them based on the description.

[0027] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0028] The technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific examples.

[0029] like Figures 1-5As shown in the embodiment of the venting device of this application, an active venting device for a large-capacity battery includes a venting membrane 1, a driving component 2, a pressure relief chamber 3, a positioning pin 4, and a battery cover 5. The core of the driving component 2 is a memory spring 21. The upper end of the memory spring 21 is connected to a conical cap 22, which has several vent holes 23 evenly distributed on it. The lower end of the memory spring 21 is connected to a circular bottom cap 24, which has four positioning holes 25 evenly distributed along its circumference. The surface of the bottom cap has several vent holes, which allows the temperature inside the battery to quickly diffuse to the pressure relief chamber, enabling the memory spring 21 to quickly sense the temperature. When the memory spring 21 reaches its operating temperature, it will elongate and deform, driving the conical cap 22 to apply stress to the venting membrane 1, piercing the venting membrane. The mixed gas inside the battery casing will then diffuse through the vent holes on the cap.

[0030] The cylindrical surface of the pressure relief chamber 3 is provided with a positioning ring 32, which is welded to the connection hole on the battery cover plate 5. The upper cylinder of the pressure relief chamber 3 is provided with a circular recess 31, and the explosion relief diaphragm 1 is welded to the circular recess 31. The lower cylinder of the pressure relief chamber 3 is provided with four positioning holes 33, which are fixed to the positioning holes 25 on the drive assembly by rivets or bolts.

[0031] The drive assembly 2 is located inside the pressure relief chamber 3. The bottom cap 24 is assembled flush with the lower surface of the pressure relief chamber and fixed to the pressure relief chamber 2 by the positioning pin 4. The vertical distance between the top of the conical cap 22 and the explosion relief membrane 1 is no more than 5mm.

[0032] The memory spring 21 is made of CuAlZn memory alloy, with a corresponding temperature range of 80–95°C. At low temperatures, the memory spring is in a stable compressed state. When the temperature reaches its abnormal temperature, the memory spring will undergo elongation deformation. This temperature range is chosen because, in most cases, the electrolyte has already begun to decompose and release gas within this temperature range. The memory spring responds within this temperature range, driving the conical cap 23 to apply point stress to the explosion vent 1, opening the explosion vent, and promptly releasing the mixed gas inside the battery, thus preventing the risk of explosion and fire caused by battery thermal runaway.

[0033] Meanwhile, under the same internal battery pressure, the pressure relief membrane is easier to open when it is pressed at one point than when it is pressed as a whole. This improves the pressure relief efficiency and prevents greater pressure damage inside the battery, thus improving battery safety.

[0034] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of this application and should not be construed as limiting the specific implementation of this application to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of this application, and all such modifications or substitutions should be considered to fall within the scope of patent protection defined by the submitted claims.

Claims

1. An active discharge device for a large-capacity battery, comprising a pressure relief chamber, a driving assembly, a pressure relief diaphragm, and a positioning pin, characterized in that, The drive assembly includes a memory spring, with a conical cap connected to the upper end and a circular bottom cap connected to the lower end. The conical cap has several vent holes, which are triangular and evenly distributed along the surface of the cone. The circular bottom cap has several positioning holes along its circumference at the folded edge, and several circular vent holes on its surface. The pressure relief chamber is a cylindrical tube, and the cylindrical tube body is provided with a positioning ring. The positioning ring is welded to the connection hole of the battery cover plate. The circular bottom cap is fixed to the pressure relief chamber by a positioning pin. The drive assembly is located below the explosion diaphragm inside the pressure relief chamber. The vertical distance between the top of the conical cap of the drive assembly and the explosion relief membrane is less than or equal to 5 mm; The upper inner wall of the pressure relief chamber is provided with a circular recess, and the explosion relief membrane is welded to the circular recess. The memory spring is made of CuZnAl memory alloy, and its operating temperature is 80-95℃.

2. The active discharge device for a large-capacity battery according to claim 1, characterized in that, The pressure relief chamber is located on a cylindrical body below the battery cover and is equipped with positioning holes. The number and position of the positioning holes are the same as those of the positioning holes on the bottom cap of the drive device.

3. The active discharge device for a large-capacity battery according to claim 1, characterized in that, The locating pin is a rivet or bolt, made of stainless steel or aluminum.

4. The active discharge device for a large-capacity battery according to claim 1, characterized in that, The cap and pressure relief chamber are made of stainless steel or aluminum.

5. A high-capacity battery, comprising an active discharge device, characterized in that, The venting device is the venting device according to any one of claims 1-4.

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