Anti-explosion valve structure and lithium battery
By introducing an expansion structure into the explosion-proof valve structure of the lithium battery, the problem of failure of the safety valve plate caused by melting the injection molded parts is solved, ensuring that the safety valve plate can work normally under high temperature conditions, and improving the safety of the battery.
Patent Information
- Application Number
- CN202420555173.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-21
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-03-21
AI Technical Summary
The existing lithium battery explosion-proof valve structure melts and bonds to the safety valve plate under high temperature conditions, resulting in the failure of the safety valve plate and increases the risk of battery explosion.
An explosion-proof valve structure is designed, including safety valve sheet, injection molded parts and expansion structure. The expansion structure expands when it reaches the set temperature to open the injection molded parts to avoid adhesion with the safety valve sheet and ensure that the safety valve sheet is at high temperature and low pressure conditions. It can work normally.
It effectively avoids the risk of failure of the safety valve plate caused by melting the injection molded parts, improves the safety of the battery, ensures that the safety valve plate can release pressure normally under high temperature conditions, and prevents the battery from exploded.
Smart Images
Figure CN222191066U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of batteries, in particular to an explosion-proof valve structure and a lithium battery. Background Art
[0002] In the prior art, an explosion-proof valve is generally installed in the upper cover assembly of a lithium battery. The explosion-proof valve includes a safety valve sheet and an injection molded part. The injection molded part is used to protect the safety valve sheet from being deformed by external forces and causing it to fail. When the internal pressure of the battery increases to the set pressure of the safety valve sheet, the safety valve sheet is opened to release the internal pressure of the battery, thereby preventing the battery from exploding. However, this mechanism of triggering the safety valve sheet to break has the following disadvantages: if the battery temperature is overheated, causing the injection molded part to melt and adhere to the safety valve sheet, the safety valve may be sealed by the injection molded part and fail. Utility Model Content
[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides an explosion-proof valve structure, which can effectively prevent the melting of the injection molded part from causing the safety valve plate to fail.
[0004] The utility model also provides a lithium battery with the explosion-proof valve structure.
[0005] The explosion-proof valve structure according to the first embodiment of the utility model includes:
[0006] Safety valve plate, installed on the upper cover plate of the lithium battery;
[0007] An injection molded part connected to the upper cover plate, the injection molded part is covered on the outer periphery of the safety valve plate, and the injection molded part is arranged on a side of the safety valve plate facing the lithium battery cell; a containing space is formed between the injection molded part and the safety valve plate;
[0008] A safety structure is arranged in the accommodating space; the safety structure includes an expansion structure, and the expansion structure is configured to expand toward one side of the injection molded part when a set temperature is reached.
[0009] The explosion-proof valve structure according to the embodiment of the utility model has at least the following beneficial effects:
[0010] By installing a safety structure on the safety valve sheet, and the safety structure can expand when the set temperature is reached, the risk of the injection molded parts of the battery melting and sticking to the safety valve sheet under high temperature and low pressure conditions, causing the safety valve to be sealed by the injection molded parts and fail, is avoided.
[0011] In an embodiment of the present invention, the difference between the set temperature of the expansion structure and the melting temperature of the injection molded part is 0°C to 20°C.
[0012] In an embodiment of the present invention, the set temperature of the expansion structure is not lower than the melting temperature of the injection molded part.
[0013] In an embodiment of the present utility model, the safety structure comprises an adhesive layer, the expansion structure is in sheet form, and the expansion structure is connected to the safety valve sheet via the adhesive layer.
[0014] In an embodiment of the present utility model, the area of the expansion structure is not greater than the area of the bonding layer, and there is a distance between the edge of the bonding layer and the edge of the safety valve sheet.
[0015] In an embodiment of the present invention, the distance between the edge of the adhesive layer and the edge of the safety valve sheet is 1 mm to 3 mm.
[0016] In an embodiment of the present invention, the area of the bonding layer is 30% to 90% of the area of the safety valve plate.
[0017] In the embodiment of the present utility model, the thickness of the bonding layer is defined as H1, the thickness of the expansion structure is defined as H2, and the height of the accommodation space is defined as H3, wherein H1+H2=(30%-95%)H3.
[0018] In an embodiment of the utility model, the injection molded part is provided with a through hole penetrating the injection molded part, the expansion structure is a granular material, and the particle size of the expansion structure is larger than the aperture of the through hole.
[0019] The lithium battery of the second embodiment of the utility model comprises the above-mentioned explosion-proof valve structure. Since the lithium battery adopts the above-mentioned explosion-proof valve structure, it at least has all the beneficial effects of the explosion-proof valve structure.
[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:
[0022] Figure 1 This is a schematic diagram of the structure of an explosion-proof valve according to an embodiment of the utility model;
[0023] Figure 2 This is a schematic structural diagram of an explosion-proof valve according to another embodiment of the utility model.
[0024] Figure Number:
[0025] Safety valve plate 100, upper cover plate 110;
[0026] Injection molded part 200, accommodating space 210;
[0027] Safety structure 300 , expansion structure 310 , and adhesive layer 320 . DETAILED DESCRIPTION
[0028] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.
[0029] In the description of the present invention, it should be understood that the descriptions involving orientation, such as the orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0030] In the description of the present utility model, "a plurality" means more than two. If there is a description of "first" or "second", it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0031] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0032] At present, an explosion-proof valve is usually installed in the upper cover plate 110 assembly of a lithium battery. The explosion-proof valve mainly includes a safety valve sheet 100 and an injection molded part 200 arranged on the periphery of the safety valve sheet 100. The function of the injection molded part 200 is to protect the safety valve sheet 100 from being directly squeezed and deformed by external force, which may cause the safety valve sheet 100 to fail. When the internal pressure of the battery increases to the set pressure of the safety valve sheet 100, the safety valve sheet 100 will be opened to release the pressure inside the battery, thereby preventing the battery from exploding. However, the existing explosion-proof valve structure does not take into account the situation where the injection molded part 200 melts due to the high temperature generated inside the battery. When the injection molded part 200 melts and adheres to the safety valve sheet 100 due to the high temperature generated inside the battery, the melted injection molded part 200 may seal the safety valve sheet 100, resulting in the safety valve sheet 100 being unable to break open when its set pressure is reached, thereby causing the risk of battery explosion. In order to solve the above technical problems, this embodiment discloses an explosion-proof valve structure, which can effectively prevent the injection molded part 200 from melting and causing the safety valve plate 100 to fail, thereby improving the safety factor of the battery. Figure 1 and2 The explosion-proof valve structure of this embodiment is described in detail.
[0033] Reference Figure 1 , Figure 2 As shown, the explosion-proof valve structure of the utility model includes a safety valve sheet 100, an injection molded part 200 and a safety structure 300. The safety valve sheet 100 is installed on the upper cover plate 110 of the lithium battery. The injection molded part 200 is connected to the upper cover plate 110 and is covered on the outer periphery of the safety valve sheet 100. The injection molded part 200 is arranged on the side of the safety valve sheet 100 facing the lithium battery cell; a receiving space 210 is formed between the injection molded part 200 and the safety valve sheet 100; the injection molded part 200 generally adopts a mesh structure to ensure that the receiving space 210 is connected to the inside of the battery; the safety structure 300 is arranged in the receiving space 210; the safety structure 300 includes an expansion structure 310, and the expansion structure 310 is configured to expand toward one side of the injection molded part 200 when the set temperature is reached to push the injection molded part 200 open, thereby preventing the injection molded part 200 from sticking to the safety valve sheet 100, thereby ensuring that the safety valve sheet 100 can function normally when its set pressure is reached.
[0034] It should be understood that the expansion structure 310 is configured to expand toward one side of the injection molded part 200 when the set temperature is reached, which does not mean that the expansion structure 310 can only expand toward one side of the injection molded part 200, but means that the expansion structure 310 can at least expand toward one side of the injection molded part 200 when the set temperature is reached. Generally speaking, the expansion structure 310 expands in multiple directions at the same time when expanding, that is, the expansion structure 310 not only expands toward one side of the injection molded part 200, but also expands in the lateral direction and in the direction away from the injection molded part 200 when expanding, but the main function of the expansion structure 310 is to lift up the injection molded part 200 to prevent the injection molded part 200 from adhering to the safety valve plate 100 and causing the safety valve plate 100 to fail.
[0035] Furthermore, since the expansion structure 310 expands in multiple directions when it expands, the expansion structure 310 will apply pressure to the injection molded part 200 and the safety valve plate 100 at the same time when it expands, and the injection molded part 200 is soft when it melts, and the safety valve plate 100 does not melt when the injection molded part 200 melts. Therefore, when the expansion structure 310 applies pressure to the injection molded part 200 and the safety valve plate 100 at the same time, the injection molded part 200 will be lifted up by the expansion structure 310, and the safety valve plate 100 will not be flushed open under the pressure of the injection molded part 200, that is, the pressure applied by the expansion structure 310 to the safety valve plate 100 when it expands is far from reaching the set pressure of the safety valve plate 100.
[0036] In the embodiment of the utility model, the expansion structure 310 is generally an endothermic expansion material, and is preferably expanded graphite. Expanded graphite can expand instantly when exposed to high temperature, so that the structure is loose, porous and curved; in addition, expanded graphite can also be combined with resin, plasticizer, etc., preferably with a ratio of 5 to 15 parts of expanded graphite, 5 to 30 parts of resin, and 1 to 20 parts of plasticizer. The plasticizer is preferably dibutyl phthalate and dioctyl phthalate, 0.5 to 10 parts of dibutyl phthalate, and 0.5 to 10 parts of dioctyl phthalate. The specific material of the expansion structure 310 can be selected according to actual conditions, and the above materials are only for reference.
[0037] In an embodiment of the present utility model, the difference between the set temperature of the expansion structure 310 and the melting temperature of the injection molded part 200 is 0°C to 20°C, and further preferably 0°C to 10°C. Generally speaking, the expansion rate of the expansion structure 310 at different temperatures is different, that is, the expansion structure 310 generally has an initial expansion temperature and a rated expansion temperature. When the initial expansion temperature of the expansion structure 310 is reached, the expansion structure 310 will begin to expand, but the expansion rate is not fast; when the rated expansion temperature of the expansion structure 310 is reached, the expansion structure 310 will be at an optimal expansion speed; the above-mentioned set temperature generally refers to the initial expansion temperature of the expansion structure 310, that is, when the temperature inside the battery reaches the set temperature, the expansion structure 310 will begin to expand, but the expansion rate will not be very fast. Therefore, in this case, the set temperature of the expansion structure 310 can be higher than the melting temperature of the injection molded part 200, or the set temperature of the expansion structure 310 can be higher than the melting temperature of the injection molded part 200. The set temperature is lower than the melting temperature of the injection molded part 200. However, if the set temperature of the expansion structure 310 is lower than the melting temperature of the injection molded part 200, the expansion structure 310 may fill the accommodating space 210 when the injection molded part 200 is not melted, which may affect the further expansion of the expansion structure 310 and may also cause part of the expansion structure 310 to partially enter the battery and affect the use of the battery. Therefore, it is most preferred that the set temperature of the expansion structure 310 is equal to the melting temperature of the injection molded part 200, but it is difficult to achieve precise control in actual production. Therefore, it is second best that the set temperature of the expansion structure 310 is not lower than the melting temperature of the injection molded part 200, that is, it is second best that the expansion structure 310 starts to expand after the injection molded part 200 starts to melt.
[0038] Furthermore, since there may be a difference between the set temperature of the expansion structure 310 and the melting temperature of the injection molded part 200, it means that if the temperature inside the battery reaches the melting temperature of the injection molded part 200 but does not reach the set temperature of the expansion structure 310, there is a situation where the injection molded part 200 melts on the expansion structure 310. At this time, it is equivalent to the injection molded part 200, the safety structure 300 and the safety valve sheet 100 being connected as a whole, which may also affect the normal use of the safety valve sheet 100. Therefore, the set temperature of the expansion structure 310 and the injection molded part 200 are different. 0 should not be too different from the melting temperature of the injection molded part 200, so as to prevent the injection molded part 200 from completely melting and sealing the safety structure 300 and the safety valve plate 100; however, when high temperature is generated inside the battery, the temperature rise rate is generally faster, that is, when the temperature inside the battery is actually out of control, it is difficult for the inside of the battery to stabilize within a smaller temperature range. Therefore, it is preferred that the set temperature of the expansion structure 310 and the melting temperature of the injection molded part 200 have a difference of 0°C to 10°C, which will not have a significant impact on actual production, and can also reduce the difficulty of production, thereby reducing production costs.
[0039] In the embodiment of the present utility model, two different forms of expansion structures 310 are proposed. Figure 1 , Figure 2 As shown, Figure 1 The middle expansion structure 310 is in sheet form. Figure 2 The expansion structure 310 is in a granular shape. Two schemes of the expansion structure 310 are described below.
[0040] by Figure 1 For example, when the expansion structure 310 is in sheet form, the safety structure 300 includes an adhesive layer 320, and the expansion structure 310 is connected to the safety valve sheet 100 through the adhesive layer 320. The connection between the adhesive layer 320 and the expansion structure 310 can better ensure that the expansion structure 310 will expand in the direction of the injection molded part 200 when expanding, and can also better fix the position of the expansion structure 310. The adhesive layer 320 is also in sheet form, and the main function of the adhesive layer 320 is to connect the expansion structure 310 and the safety valve sheet 100. Therefore, the material of the adhesive layer 320 does not need to be limited, and it only needs to achieve the effect of connecting the expansion structure 310 and the safety valve sheet 100.
[0041] Furthermore, to ensure that the expansion structure 310 and the bonding layer 320 do not affect the safety valve sheet 100, the area of the bonding layer 320 should be smaller than the area of the safety valve sheet 100, and there should be a gap between the edge of the bonding layer 320 and the edge of the safety valve sheet 100. In addition, the area of the expansion structure 310 should not be larger than the area of the bonding layer 320. Specifically, it is preferred that the area of the bonding layer 320 is 30% to 90% of the area of the safety valve, and the gap between the edge of the bonding layer 320 and the edge of the safety valve sheet 100 is 1 mm to 3 mm; further, it is preferred that the area of the expansion structure 310 is equal to the area of the bonding layer 320.
[0042] It is conceivable that the expansion structure 310 may also be connected to the inner side of the injection molded part 200 via the adhesive layer 320 .
[0043] In the embodiment of the present invention, the thickness of the adhesive layer 320 is defined as H1, the thickness of the expansion structure 310 is defined as H2, and the height of the accommodation space 210 is defined as H3, wherein H1+H2=(30%-95%)H3. Specifically, the thickness of the adhesive layer 320 plus the thickness of the expansion structure 310 is the thickness of the safety structure 300, and the thickness of the safety structure 300 is preferably not less than 30% of the height of the accommodation space 210 in order to ensure that there is enough expansion structure 310 to expand to push open the melted injection molded part 200, and the thickness of the safety structure 300 is set not higher than 95% of the height of the accommodation space 210 in order to leave room for error. For example, if a high temperature phenomenon occurs briefly inside the battery, the temperature inside the battery rises to above the expansion temperature of the expansion structure 310 in a short period of time and then drops rapidly. In this case, the injection molded part 200 may not melt completely, but can continue to maintain the original frame. In a short period of time, since the temperature reaches above the set temperature of the expansion structure 310, the expansion structure 310 will stop expanding after partial expansion. In this case, since the thickness of the safety structure 300 is less than the height of the accommodating space 210, after such a short high temperature phenomenon occurs, although the expansion structure 310 partially expands, the increase in volume is limited and will not damage the structure of the injection molded part 200. Therefore, the explosion-proof valve structure of this embodiment can continue to be used, avoiding excessive wear of the explosion-proof valve structure, thereby reducing the maintenance cost of the battery.
[0044] In the embodiment of the present utility model, Figure 2 For example, when the expansion structure 310 is in a granular form, the safety structure 300 does not include the adhesive layer 320, the injection molded part 200 is provided with a through hole penetrating the injection molded part 200, and the particle size of the expansion structure 310 is larger than the aperture of the through hole to prevent the expansion structure 310 from falling into the battery from the accommodation space 210. The expansion structure 310 of this embodiment is simpler, and the volume of the expansion structure 310 preferably accounts for 30% to 95% of the volume of the accommodation space 210.
[0045] The utility model also discloses a lithium battery, which includes the above-mentioned explosion-proof valve structure. Since the lithium battery adopts the above-mentioned explosion-proof valve structure, it at least has all the beneficial effects of the explosion-proof valve structure, which will not be described in detail here. It can be imagined that the explosion-proof valve structure of this embodiment can also be applied to batteries such as sodium batteries.
[0046] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.
[0047] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.
Claims
1. An explosion-proof valve structure, characterized in that: include: Safety valve plate, installed on the upper cover plate of the lithium battery; An injection molded part connected to the upper cover plate, the injection molded part is covered on the outer periphery of the safety valve plate, and the injection molded part is arranged on a side of the safety valve plate facing the lithium battery cell; a receiving space is formed between the injection molded part and the safety valve plate; A safety structure is arranged in the accommodating space; the safety structure includes an expansion structure, and the expansion structure is configured to expand toward one side of the injection molded part when a set temperature is reached.
2. The explosion-proof valve structure according to claim 1, characterized in that: The difference between the set temperature of the expansion structure and the melting temperature of the injection molded part is 0°C to 20°C.
3. The explosion-proof valve structure according to claim 1, characterized in that: The set temperature of the expansion structure is not lower than the melting temperature of the injection molded part.
4. The explosion-proof valve structure according to claim 1, characterized in that: The safety structure comprises an adhesive layer, the expansion structure is in sheet form, and the expansion structure is connected to the safety valve sheet via the adhesive layer.
5. The explosion-proof valve structure according to claim 4, characterized in that: The area of the expansion structure is not greater than the area of the bonding layer, and there is a distance between the edge of the bonding layer and the edge of the safety valve sheet.
6. The explosion-proof valve structure according to claim 5, characterized in that: The distance between the edge of the bonding layer and the edge of the safety valve sheet is 1 mm to 3 mm.
7. The explosion-proof valve structure according to claim 4, characterized in that: The area of the bonding layer is 30% to 90% of the area of the safety valve sheet.
8. The explosion-proof valve structure according to claim 5, characterized in that: The thickness of the bonding layer is defined as H1, the thickness of the expansion structure is defined as H2, and the height of the accommodation space is defined as H3, wherein H1+H2=(30%-95%)H3.
9. The explosion-proof valve structure according to claim 1, characterized in that: The injection molded part is provided with a through hole penetrating the injection molded part, the expansion structure is in a granular form, and the particle size of the expansion structure is larger than the aperture of the through hole.
10. A lithium battery, characterized in that: It comprises an upper cover plate, on which the explosion-proof valve structure according to any one of claims 1 to 9 is installed.