Battery cell explosion-proof structure and battery cell

Abstract

The utility model provides a battery cell explosion-proof structure and a battery cell. The battery cell explosion-proof structure comprises an air outlet formed in a mounting base, wherein the air outlet is blocked by a valve plate; a cavity is formed in the shell, the shell is fixedly connected and kept in the thermal environment space below the mounting foundation, and an opening facing the air outlet is formed in one end of the shell; the lower end of the push rod is inserted into the shell through the opening in a sliding and sealing manner, and the upper end is exposed outside the shell; the filler is filled in the shell, and the volume of the filler is increased along with the increase of the temperature; when the volume of the filler is increased to drive the push rod to get close to the air outlet, the puncture part gradually gets close to and punctures the valve plate. According to the explosion-proof structure of the battery cell, the filler is arranged in the shell, and the filler drives the push rod to pierce the valve plate due to the temperature rise in the thermal environment space, so that the effect of reducing the pressure in the shell of the battery cell is realized, the safety performance of the battery cell is improved, and the explosion-proof structure of the battery cell has good practicability.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and in particular to an explosion-proof structure of a battery cell. The utility model also relates to a battery cell provided with the explosion-proof structure of the battery cell. Background Art

[0002] With the country's planning and support for the development of the new energy vehicle industry, the market share of new energy vehicles has continued to increase, and pure electric or hybrid vehicles have become more and more popular in people's lives. Among them, the safety of vehicle battery packs has become one of the important performance indicators of battery vehicles. The battery pack contains multiple cells, which can generate electricity through electrochemical reactions and transmit it outside the battery pack to provide electricity to the electric vehicle and drive the electric vehicle.

[0003] When the battery cell is in an abnormal working state and the temperature inside the battery cell is too high, the battery cell will experience thermal runaway, which will cause the electrode group inside the battery cell to be damaged and melted, and a large amount of gas will be generated. The accumulation of this gas in the battery pack will cause the pressure inside the battery pack to continue to increase. If the gas generated by the battery module cannot be discharged to the outside of the battery cell, the battery cell and the battery pack containing the battery cell will explode, causing damage to the vehicle and personnel.

[0004] In order to prevent the battery cell from exploding due to thermal runaway, a pressure relief exhaust device is usually provided on the shell of the battery cell, which is used to discharge the gas in the battery cell to the outside of the battery cell when the internal pressure of the battery cell is too high due to thermal runaway, so as to prevent the battery cell from exploding due to excessive internal pressure. Generally speaking, the pressure relief exhaust device on the shell of the battery cell is usually an explosion-proof valve. When the pressure in the battery cell reaches a certain threshold, the explosion-proof valve is pushed by the gas in the battery cell and opens, thereby reducing the pressure of the gas discharged from the battery cell. However, the existing explosion-proof valve is triggered by the pressure of the gas in the battery cell and the triggering pressure value is large. In the case of thermal runaway of some battery cells, the temperature in the battery cell is first too high, and then the battery cell is prone to deflagration and produces a large amount of gas, causing the pressure in the battery cell to rise rapidly in a short period of time. At this time, the explosion-proof valve cannot immediately exhaust the gas to reduce the pressure, thereby causing the battery cell to explode. Utility Model Content

[0005] In view of this, the utility model aims to provide a battery core explosion-proof structure, which can reduce the pressure inside the battery core when the temperature of the battery core is too high, thereby improving the safety performance of the battery core.

[0006] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0007] A battery cell explosion-proof structure comprises an air outlet, which is arranged on a mounting base and is blocked by a valve sheet; a shell with a cavity formed inside, the shell is fixedly connected and maintained in a thermal environment space below the mounting base, and one end of the shell is provided with an opening facing the air outlet; a push rod, the lower end of the push rod is inserted into the shell through the opening in a sliding and sealed manner, the upper end is exposed to the outside of the shell and is formed with a puncture portion facing the valve sheet; a filler is filled in the shell, the volume of the filler increases with the increase of temperature; when the push rod is driven close to the air outlet due to the increase of the volume of the filler, the puncture portion gradually approaches and punctures the valve sheet.

[0008] Furthermore, the puncture portion includes a base plate fixed to the upper end of the push rod, and a plurality of puncture needles arranged on the base plate; the puncture needles are distributed on the base plate at intervals along the extension direction of the valve sheet.

[0009] Furthermore, the valve plate is provided with a plurality of notches corresponding to the positions of the puncture needles.

[0010] Furthermore, a blocking portion extending radially along the push rod is provided on the lower end of the push rod; when the push rod approaches the air outlet, the blocking portion can gradually approach and abut against the top inner wall of the shell.

[0011] Furthermore, the outer periphery of the blocking portion is sealed and fitted with the inner wall of the shell, and a filling space is formed between the blocking portion and the bottom inner wall of the shell, and the filler is located in the filling space.

[0012] Furthermore, a channel extending along the axial direction is formed in the push rod, and the channel is connected to the filling space.

[0013] Furthermore, the filler is paraffin.

[0014] Furthermore, the installation base is a battery cell cover plate.

[0015] Furthermore, an elastic member is provided between the push rod and the housing, and the elastic member is compressed and stores energy when the push rod is close to the mounting base.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] The battery cell explosion-proof structure described in the utility model arranges a filler in the shell and utilizes the characteristic that the volume of the filler increases with the increase of temperature. The volume of the filler increases with the increase of temperature in the thermal environment space, and then the filler drives the push rod to puncture the valve sheet, and the gas in the battery pack is discharged through the outlet, thereby achieving the effect of reducing the pressure in the battery cell shell, improving the safety performance of the battery cell, and having good practicality.

[0018] The puncture part on the push rod includes a base plate and a plurality of puncture needles arranged on the base plate. The puncture needles are spaced apart along the extension direction of the valve sheet. Through the arrangement of the plurality of puncture needles, the puncture part can create a larger opening on the valve sheet when puncturing the valve sheet, thereby ensuring that the valve sheet can be ruptured due to the pressure in the battery cell, so that the gas in the battery cell can be discharged.

[0019] The valve plate is provided with a plurality of notches corresponding to the positions of the puncture needles. The notches serve as the weak points of the valve plate, and the puncture needles can easily puncture the valve plate through the notches, thereby ensuring that the valve plate can be opened by the push rod.

[0020] A blocking portion is provided at the lower end of the push rod. When the push rod is close to the air outlet, the blocking portion can abut against the inner wall of the top of the shell, thereby preventing the push rod from separating from the shell.

[0021] The outer periphery of the blocking portion fits tightly with the inner wall of the shell to form a filling space. The filler is arranged in the filling space. There is a large contact area between the filler and the blocking portion. When the volume of the filler increases and pushes the push rod toward the air outlet, the force of the filler pushing the push rod is increased, thereby increasing the force of the puncture portion to puncture the valve plate and ensuring that the valve plate ruptures.

[0022] A channel connected to the filling space is formed in the push rod, and the filling amount of the filler in the channel can be increased, while at the same time facilitating the push rod to be pushed toward the air outlet to a certain extent.

[0023] Paraffin is used as a filler in the shell cavity. It is solid at room temperature, so it can be filled in the shell to avoid leakage from the shell. At the same time, paraffin can melt when the battery pack is thermally runaway to increase its volume, thereby effectively pushing the shell to move. At the same time, the temperature at which the detection device is triggered can be controlled by selecting paraffin with different grades.

[0024] The battery cover serves as an installation base to facilitate the installation and maintenance of the battery explosion-proof structure.

[0025] An elastic member is provided between the push rod and the shell, which can apply pressure to the push rod to prevent the push rod from moving and damaging the valve plate when the explosion-proof structure of the battery cell is not triggered, thereby reducing the sealing of the battery cell and affecting the normal operation and service life of the battery cell.

[0026] Another object of the present invention is to provide a battery cell, in which the battery cell explosion-proof structure as described above is provided.

[0027] The battery cell described in the utility model and the battery cell explosion-proof structure described above have the same beneficial effects as the prior art, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of the overall structure of the battery core explosion-proof structure according to the first embodiment of the utility model;

[0030] Figure 2 This is a schematic diagram of the internal structure of the battery core explosion-proof structure when it is not triggered according to the first embodiment of the utility model;

[0031] Figure 3 This is a schematic diagram of the internal structure of the battery core explosion-proof structure when it is triggered according to the first embodiment of the utility model;

[0032] Description of reference numerals:

[0033] 1. air outlet; 101. valve plate; 102. notch;

[0034] 2. Installation foundation;

[0035] 3. Shell; 301. Connector; 302. Bump; 303. Second sealing ring;

[0036] 4. push rod; 401. substrate; 402. needle; 403. blocking part; 404. first sealing ring; 405. channel;

[0037] 5. Filler; 6. Cell cover; 7. Elastic part. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0039] In the description of the present invention, it should be noted that if there are terms such as "upper", "lower", "inner", "outer" and the like indicating orientation or positional relationship, they 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 limiting the present invention. In addition, if there are terms such as "first" and "second", they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0040] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection" and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0042] Embodiment 1

[0043] This embodiment relates to a battery cell explosion-proof structure, which is used to reduce the pressure in the battery pack when the battery cell is overheated or thermal runaway occurs. Figure 1 , Figure 2 and Figure 3 As shown, the battery core explosion-proof structure of this embodiment includes an air outlet 1, a shell 3, a push rod 4 and a filler 5.

[0044] Among them, the air outlet 1 is arranged on a mounting base 2, and the air outlet 1 is blocked by a valve plate 101. A cavity is formed in the shell 3, and the shell 3 is fixedly connected and maintained in the thermal environment space below the mounting base 2, and one end of the shell 3 is provided with an opening facing the air outlet 1. The lower end of the push rod 4 is inserted into the shell 3 through the above-mentioned opening in a sliding and sealed manner, and the upper end of the push rod 4 is exposed to the outside of the shell 3, and a puncture portion facing the valve plate 101 is formed. The shell 3 is filled with a filler 5, and the volume of the filler 5 can increase with the increase of temperature. When the push rod 4 is driven close to the air outlet 1 due to the increase in the volume of the filler 5, the puncture portion gradually approaches and punctures the valve plate 101, so that the valve plate 101 ruptures under the action of the pressure in the battery cell, and the air outlet 1 is opened to discharge the gas in the battery cell.

[0045] It is understandable that the push rod 4 has an opening at the upper end of the shell 3 and is inserted into the shell 3, and can move along the length direction of the push rod 4 away from or close to the valve plate 101. When the push rod 4 is away from the valve plate 101, part of the push rod 4 is located in the cavity of the shell 3 and occupies part of the volume of the cavity, and the volume of the cavity is small at this time. When the push rod 4 is close to the mounting base 2, part of the push rod 4 leaves the cavity, and the volume of the cavity becomes larger at this time. Since the volume of the filler 5 changes with temperature, when the volume of the filler 5 increases, the filler 5 drives the push rod 4 to approach the valve plate 101, thereby increasing the volume of the cavity to accommodate the filler 5. When the temperature of the thermal environment space in the battery cell is raised to a preset value, the volume of the filler 5 increases and drives the push rod 4 to move, so that the puncture portion on the push rod 4 pierces the valve plate 101 to discharge the gas in the battery cell.

[0046] As described above, by arranging the filler 5 in the shell 3 and utilizing the characteristic that the volume of the filler 5 increases with the increase of temperature, the volume of the filler 5 increases with the increase of temperature in the thermal environment space, and then the filler 5 drives the push rod 4 to pierce the valve sheet 101, and the gas in the battery pack is discharged through the outlet 1, thereby achieving the effect of reducing the pressure in the battery cell shell 3, improving the safety performance of the battery cell, and having good practicality.

[0047] Based on the above overall introduction, continue to combine Figure 1 , Figure 2 and Figure 3 As shown, the present embodiment is fixed below the mounting base 2 by a U-shaped connector 301, and the thermal environment space is the space inside the battery cell shell 3. The shell 3 is a cylindrical structure, and the shell 3 can preferably be made of metal material, which has good thermal conductivity, so that the heat in the thermal environment space can be quickly and accurately transferred to the filler 5 in the shell 3, thereby improving the sensitivity of the present battery cell explosion-proof structure to temperature. In addition, the gas outlet 1 of the present embodiment is a waist-shaped hole to increase the gas flow area of ​​the gas outlet 1.

[0048] In order to ensure that the valve sheet 101 is effectively ruptured by being punctured by the puncture part, the puncture part of this embodiment includes a base plate 401 fixed to the upper end of the push rod 4, and a plurality of puncture needles 402 arranged on the base plate 401, and each puncture needle 402 is distributed on the base plate 401 at intervals along the extension direction of the valve sheet 101, and the base plate 401 is a plate-shaped structure slightly smaller than the gas outlet 1. Compared with only a single puncture needle 402, by providing a plurality of puncture needles 402, the puncture part can cause a larger damage hole on the valve sheet 101, thereby reducing the structural strength of the valve sheet 101, ensuring that the valve sheet 101 can be ruptured due to the pressure in the battery cell, so that the gas in the battery cell is discharged.

[0049] Since the push rod 4 is driven to move due to the increase in the volume of the filler 5, the puncture force of the puncture part on the valve sheet 101 is limited. In order to further ensure that the valve sheet 101 can be punctured by the puncture part, the valve sheet 101 of this embodiment is provided with a plurality of notches 102 corresponding to the positions of the puncture needles 402. The notches 102 are the weak points of the valve sheet 101, so that when the puncture needles 402 puncture the notches 102, it is easier to puncture the valve sheet 101. In a specific implementation, the notches 102 can be connected to each other to form an annular notch 102 arranged around the air outlet 1, and the puncture needles 402 are spaced and arranged in an annular shape on the substrate 401 along the extension direction of the notches 102. When the puncture force punctures the valve sheet 101, each puncture needle 402 pierces the notch 102, causing a number of damaged openings on the annular notch 102, so that the connection strength between the middle of the valve sheet 101 and the edge of the valve sheet 101 decreases. Under the action of the pressure in the battery cell, the middle of the valve sheet 101 is disconnected from the edge of the valve sheet 101, causing the valve sheet 101 to rupture.

[0050] In order to prevent the push rod 4 from separating from the shell 3 when moving, a blocking portion 403 extending radially along the push rod 4 is provided on the lower end of the push rod 4 of the present embodiment. When the push rod 4 approaches the air outlet 1, the blocking portion 403 can gradually approach and abut against the top inner wall of the shell 3, so that the push rod 4 is blocked to avoid it from separating from the shell 3, and at the same time prevent the substrate 401 of the puncture portion from being blocked or affecting the smooth exhaust of the air outlet 1.

[0051] In order to increase the thrust of the filler 5 on the push rod 4 and enable the puncture portion of the follower push rod 4 to effectively puncture the valve sheet 101, in this embodiment, the outer periphery of the blocking portion 403 is sealed and fitted with the inner wall of the housing 3, and a filling space is formed between the blocking portion 403 and the bottom inner wall of the housing 3, and the filler 5 is located in the filling space. When the volume of the filler 5 increases in the filling space due to the increase in the temperature of the thermal environment space, the filler 5 will push against one end of the blocking portion 403. Compared with the filler 5 pushing against the rod of the push rod 4, the setting of the blocking portion 403 can effectively increase the contact area between the filler 5 and the push rod 4, thereby increasing the thrust of the filler 5 on the push rod 4, thereby enabling the puncture portion to effectively puncture the valve sheet 101. In specific implementation, a first sealing ring 404 can be embedded on the outer periphery of the blocking portion 403 to ensure the sealing of the filling space and prevent part of the filler 5 from overflowing from the filling space when the filler 5 expands, making the explosion-proof structure of the battery cell invalid. In addition, a convex block 302 is provided at the upper end of the housing 3 and is arranged around the opening. The second sealing ring 303 is embedded in the convex block 302 to ensure the sealing between the housing 3 and the push rod 4.

[0052] In order to increase the distance that the push rod 4 is pushed out by the filler 5 and ensure that the push rod 4 effectively punctures the valve sheet 101, a channel 405 extending along the axial direction is formed in the push rod 4 of this embodiment, and the channel 405 is connected to the filling space. Without increasing the size of the shell 3, that is, the filling space, the filling amount of the filler 5 can be effectively increased, so that the increase in the volume of the filler 5 is increased, thereby increasing the moving distance of the push rod 4, and can save the space in the battery cell to a certain extent, reducing the space occupied by the explosion-proof structure of the battery cell.

[0053] In order to increase the volume of the filler 5 as the temperature rises, so that the explosion-proof structure of the battery cell of this embodiment can be triggered at a preset temperature value, the filler 54 of this embodiment is paraffin. It can be understood that paraffin is solid at room temperature, and solid paraffin can be easily filled in the shell 3, and compared with the liquid filler 5, it is not easy to leak from the shell 3, so it is easy to produce. At the same time, the melting point of paraffin is about 50-100°C, and the volume changes significantly when the solid paraffin melts into liquid, which can effectively drive the push rod 4 to move. In addition, the temperature range of paraffin melting is close to the temperature range where the battery cell overheats and thermal runaway occurs, and various types of paraffin are divided into different varieties and brands according to the melting point every 2°C. By selecting the appropriate brand of paraffin, the melting temperature of the paraffin can correspond to the thermal runaway temperature of the battery cell, so that when the battery cell overheats and the internal pressure of the battery cell is too high, the puncture part of the push rod 4 can puncture the valve plate 101, so that the gas in the battery cell is discharged through the gas outlet 1, thereby reducing the pressure in the battery cell and improving the safety performance of the battery cell. In specific implementation, the filler 5 of this embodiment uses No. 70 paraffin, which melts when the temperature in the thermal environment space, that is, the temperature in the battery cell housing 3 reaches 70°C.

[0054] In order to facilitate the installation and maintenance of the battery cell explosion-proof structure of this embodiment, in this embodiment, the installation base 2 is the battery cell cover 6. It can be understood that the battery cell cover 6 is a cover on the battery cell shell 3, and the internal components of the battery cell can be maintained by opening the battery cell cover 6. Therefore, the battery cell cover 6 as the installation base 2 can facilitate the maintenance work of the maintenance personnel.

[0055] The battery cell is usually arranged in a battery pack, and the battery pack will be subjected to bumps and vibrations due to the movement of the vehicle. When the battery cell is subjected to bumps and vibrations due to the movement of the vehicle, the push rod 4 and the puncture part may be close to the valve plate 101 due to the vibration, causing damage to the valve plate 101, resulting in a decrease in the sealing of the battery cell, and affecting the normal operation and service life of the battery cell. Therefore, in this embodiment, an elastic member 7 is provided between the push rod 4 and the shell 3, and the elastic member 7 can apply a pressure to the push rod 4, so that when the battery cell explosion-proof structure is not triggered, the push rod 4 can be stably guaranteed in the shell 3 without moving. At the same time, the elastic member 7 is compressed and stored because the push rod 4 is close to the installation base 2, so that the battery cell explosion-proof structure of this embodiment is triggered and the push rod 4 is reset after the temperature in the battery cell drops, so that the battery cell explosion-proof structure has the possibility of being reused after maintenance and overhaul. In a specific implementation, the elastic member 7 is in contact between the blocking portion 403 and the inner wall of the top of the housing 3, and the elastic member 7 can be a spring wound on the push rod 4, which has a simple structure and can effectively achieve the above-mentioned functions. At the same time, the downward pressure exerted by the spring on the push rod 4 should be small, so that the filler 5 can drive the push rod 4 close to the air outlet 1 when the volume increases.

[0056] In summary, the battery cell explosion-proof structure of the present embodiment arranges a filler 5 in the shell 3 and utilizes the characteristic that the volume of the filler 5 increases with the temperature increase, so that the volume of the filler 5 increases due to the temperature increase in the thermal environment space, and then the filler 5 drives the push rod 4 to pierce the valve sheet 101, and the gas in the battery pack is discharged through the outlet 1, thereby achieving the effect of reducing the pressure in the battery cell shell 3, improving the safety performance of the battery cell, and having good practicality.

[0057] Embodiment 2

[0058] This embodiment relates to a battery cell, in which the battery cell explosion-proof structure as described in the first embodiment is provided.

[0059] The battery cell of this embodiment has the same beneficial effects as the prior art by being provided with the battery cell explosion-proof structure as described in the first embodiment, so as to reduce the pressure inside the battery cell shell and improve the safety performance of the battery cell when the battery cell overheats or thermal runaway occurs.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery core explosion-proof structure, characterized in that: include: An air outlet, the air outlet is arranged on the installation base, and the air outlet is blocked by a valve plate; A shell with a cavity formed inside, the shell is fixedly connected and maintained in the thermal environment space below the installation base, and one end of the shell is provided with an opening facing the air outlet; A push rod, the lower end of which is inserted into the housing in a sliding and sealing manner through the opening, the upper end of which is exposed to the outside of the housing and is formed with a puncture portion facing the valve sheet; A filler filled in the shell, wherein the volume of the filler increases with increasing temperature; When the push rod is driven close to the air outlet due to the increase in volume of the filler, the puncture portion gradually approaches and punctures the valve sheet.

2. The explosion-proof structure of the battery cell according to claim 1, characterized in that: The puncture part comprises a base plate fixed on the upper end of the push rod, and a plurality of puncture needles arranged on the base plate; the puncture needles are distributed on the base plate at intervals along the extension direction of the valve sheet.

3. The explosion-proof structure of the battery cell according to claim 2, characterized in that: The valve sheet is provided with a plurality of notches corresponding to the positions of the puncture needles.

4. The explosion-proof structure of the battery cell according to claim 1, characterized in that: A blocking portion extending radially along the push rod is provided on the lower end of the push rod; when the push rod approaches the air outlet, the blocking portion can gradually approach and abut against the top inner wall of the shell.

5. The explosion-proof structure of the battery cell according to claim 4, characterized in that: The outer periphery of the blocking portion is sealed and fitted with the inner wall of the shell, and a filling space is formed between the blocking portion and the bottom inner wall of the shell, and the filler is located in the filling space.

6. The explosion-proof structure of the battery cell according to claim 5, characterized in that: A channel extending along the axial direction is formed in the push rod, and the channel is connected to the filling space.

7. The explosion-proof structure of the battery cell according to claim 1, characterized in that: The filler is paraffin.

8. The explosion-proof structure of the battery cell according to claim 1, characterized in that: The installation base is a battery cell cover plate.

9. The explosion-proof structure of a battery cell according to any one of claims 1 to 8, characterized in that: An elastic member is provided between the push rod and the housing, and the elastic member is compressed and stores energy when the push rod is close to the mounting base.

10. A battery cell, characterized in that: The battery cell is provided with the battery cell explosion-proof structure according to any one of claims 1 to 9.

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