Single battery and battery pack

Abstract

The invention discloses a single battery and a battery pack, and belongs to the technical field of batteries, the single battery comprises: a shell having an accommodating cavity and an opening communicated with the accommodating cavity; the cover plate covers the opening and is connected with the shell, and the cover plate is provided with a first groove and a through hole communicated with the first groove and the containing cavity; and the first sealing piece penetrates through the through hole. The through hole is formed in the cover plate, then the first sealing piece penetrates through the through hole, the first sealing piece and the through hole are in interference fit, and therefore the anti-explosion structure is formed, due to the fact that an original indented anti-explosion valve is provided with a cover plate material and machining errors, the actual valve opening pressure and the preset valve opening pressure have large errors, and a battery cannot be opened in time for pressure relief; according to the explosion-proof structure, the valve opening accuracy is high, when thermal runaway happens to the battery, after the interior reaches the preset pressure, gas generated in the battery can rapidly extrude the first sealing piece out of the interior of the through hole, so that the battery can be subjected to pressure relief through the through hole, and explosion of the battery is prevented.

Description

Technical Field

[0001] This application belongs to the technical field of batteries, and particularly relates to a single battery and a battery pack. Background Art

[0002] In order to improve the safety during the use of batteries, an explosion-proof valve is often provided thereon to achieve the effect of explosion prevention. For cylindrical batteries, the cover plate is usually welded to the steel shell with an open bottom, and then a notch is provided on the cover plate to form an explosion-proof valve structure on the cover plate. However, due to processing errors and production fluctuations, the actual opening pressure of the notch and the set pressure deviate greatly. In the case of thermal runaway of the cylindrical battery, the internal pressure of the battery cannot be relieved in time, which may cause the battery to explode. Summary of the Invention

[0003] Object of the Invention: The embodiments of this application provide a single battery, aiming to overcome the technical problem that when the battery undergoes thermal runaway, the internal pressure of the battery cannot be relieved in time, which may cause the battery to explode; another object of the embodiments of this application is to provide a battery pack.

[0004] Technical Solution: A single battery according to an embodiment of this application includes:

[0005] A housing having a receiving cavity and an opening communicating with the receiving cavity;

[0006] A cover plate covering the opening and connected to the housing, the cover plate having a first groove and a through hole communicating the first groove and the receiving cavity;

[0007] A first seal member passing through the through hole and having an interference fit with the through hole, the first seal member having a connecting groove communicating with the receiving cavity, and the connecting groove being configured to increase the contact area between the first seal member and the internal gas of the receiving cavity.

[0008] In some embodiments, the inner wall of the connecting groove is an arc surface or a spherical surface.

[0009] In some embodiments, the inner wall of the connecting groove includes a plurality of planes, and two adjacent planes are connected to each other and inclined to each other.

[0010] In some embodiments, the first seal member is a flexible structure; the first seal member includes:

[0011] A first main body portion disposed in the first groove;

[0012] A second main body part is connected to the first main body part. The second main body part passes through the through hole into the accommodation cavity and is in interference fit with the through hole. The connection groove is formed on a side of the second main body part facing away from the first main body part.

[0013] A folding part is located in the accommodation cavity and is connected to the second main body part. The folding part surrounds the second main body part and extends in a direction away from the connection groove along the radial direction of the second main body part.

[0014] In some embodiments, an inclined surface is provided on the outer periphery of the folding part. Along the radial direction of the second main body part and in a direction away from the connection groove, the minimum distance from the inclined surface to the cover plate gradually decreases.

[0015] In some embodiments, the first groove has a side wall, and the side wall is inclined with respect to the height direction.

[0016] Along a direction perpendicular to the height direction, there is a spacing D between the first main body part and the side wall. In a direction of the first main body part facing away from the second main body part, the spacing D gradually increases.

[0017] In some embodiments, the single battery includes:

[0018] A second seal, which covers the first groove and is connected to the cover plate.

[0019] In some embodiments, the cover plate has a second groove communicating with the first groove. The second seal is disposed in the second groove. The dimension of the second groove in the height direction of the housing is L1, and the dimension of the second seal in the height direction is L2, satisfying: L1≥L2.

[0020] In some embodiments, the cover plate includes an inner circular part and an outer circular part. The outer circular part surrounds the inner circular part. The inner side of the outer circular part is connected to the inner circular part, and the outer side of the outer circular part is connected to the housing. The first groove and the through hole are provided on the inner circular part. The second seal covers the first groove and the through hole and is connected to the inner circular part.

[0021] The cover plate further includes a notch, which is provided between the inner circular part and the outer circular part and is respectively connected to the inner circular part and the outer circular part. At least part of the notch is an arc-shaped structure.

[0022] A battery pack includes the single battery described above.

[0023] Beneficial effects: The single cell of the embodiment of the present application includes: a housing having a receiving cavity and an opening communicating with the receiving cavity; a cover plate covering and sealing the opening and connected to the housing, the cover plate having a first groove and a through hole communicating the first groove and the receiving cavity; a first seal passing through the through hole and in interference fit with the through hole, the first seal having a connecting groove communicating with the receiving cavity, and the connecting groove being configured to increase the contact area between the first seal and the internal gas of the receiving cavity. By providing a through hole in the cover plate and then using the first seal to penetrate the through hole to make an interference fit between the two, an explosion-proof structure is formed. Due to the cover plate material and processing error of the original scored explosion-proof valve, there is a large error between the actual opening pressure and the preset opening pressure, and the battery cannot open the valve and relieve pressure in time. The explosion-proof structure of the present application has high opening accuracy. When the battery undergoes thermal runaway and reaches the preset pressure inside, the gas generated inside the battery can quickly extrude the first seal out of the inside of the through hole, so that the battery can relieve pressure through the through hole to prevent the battery from exploding. At the same time, a connecting groove is provided on the first seal, and the setting of the connecting groove increases the contact area between the gas generated inside the battery and the first seal, making it easier for the gas with a certain pressure to push the first seal. When the battery undergoes thermal runaway, the through hole is easier to open, further improving the opening accuracy of the explosion-proof structure. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 Is a perspective view of the single cell of the embodiment of the present application;

[0026] Figure 2 Is a front view cross-sectional view of the single cell of the embodiment of the present application;

[0027] Figure 3 Is a partial cross-sectional view of the connection between the cover plate and the housing of the embodiment of the present application;

[0028] Figure 4 For the embodiment of the present application Figure 3 Is a partial enlarged view of area A in;

[0029] Figure 5 Is a perspective view of the first seal of the embodiment of the present application;

[0030] Figure 6 Is a front view cross-sectional view of the first seal of the embodiment of the present application, wherein the inner wall of the connecting groove is spherical;

[0031] Figure 7 A perspective view of the first seal of the embodiment of the present application, wherein the inner wall of the connecting groove is an arc surface;

[0032] Figure 8 A perspective view of the first seal of the embodiment of the present application, wherein the inner wall of the connecting groove is a plane;

[0033] Figure 9 A front sectional view of the first seal of the embodiment of the present application, wherein the inner wall of the connecting groove is a plane;

[0034] Figure 10 A front view of the cover plate of the embodiment of the present application;

[0035] Figure 11 A top sectional view of the cover plate of the embodiment of the present application;

[0036] Figure 12 A top sectional view of the cover plate of the embodiment of the present application, wherein the second seal is connected to the cover plate;

[0037] Figure 13 For the embodiment of the present application Figure 12 A partial enlarged view of area B in the embodiment;

[0038] Figure 14 A perspective view of a single cell with a second seal of the embodiment of the present application;

[0039] Reference numerals: 10 - housing; 11 - accommodating cavity; 12 - opening; 20 - cover plate; 21 - first groove; 211 - side wall; 22 - through hole; 23 - second groove; 24 - inner circular part; 25 - outer circular part; 26 - notch; 30 - first seal; 31 - connecting groove; 32 - first main body part; 33 - second main body part; 34 - folding part; 341 - inclined surface; 40 - second seal; X - height direction. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0041] In the description of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality" is two or more, and at least one means one, two, or more, unless otherwise specifically defined.

[0042] Existing large cylindrical batteries usually adopt a steel shell with an open bottom. The wound core electrode group is arranged inside the shell and is encapsulated by peripheral laser welding of the bottom cover plate to the open end of the shell; a notch is provided on the bottom sealing cover plate, and the ratio of the circumference of the notch to the circumference of the corresponding circle is usually less than 0.95, which can thus function as an explosion-proof valve. By controlling the residual thickness of the notch on the cover plate, it is ensured that the explosion-proof valve can be normally opened under the set air pressure, meeting the explosion-proof pressure for opening when the battery cell gets out of control, preventing the battery from deforming and causing the shell to burst or the battery cell to explode, and ensuring the safety of the battery cell. Large cylindrical batteries usually have a relatively small capacity. Only by ensuring that the explosion-proof valve opens at the set pressure can the safety of the battery cell be guaranteed. For cylindrical batteries with a steel shell, due to processing errors and production fluctuations, the actual opening pressure of the notch explosion-proof valve on the cover plate deviates greatly from the set pressure. In extreme cases such as thermal runaway of the cylindrical battery, the inside of the battery cannot be depressurized in time, and there may be risks such as the shell bursting or the battery exploding.

[0043] In view of this, an embodiment of the present application provides a single battery to overcome at least one of the above technical problems.

[0044] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 , in the embodiment of the present application, the single battery includes: a shell 10, a cover plate 20, and a first sealing member 30. The single battery can be a cylindrical battery, and the shell 10 of the cylindrical battery is usually made of a metal material, such as steel or aluminum. The main function of the shell 10 is to provide the structural support of the battery and protect the internal components. The cover plate 20 of the cylindrical battery is usually located at one end of the battery and is used to enclose the structure of the battery and protect the internal components. It is usually made of a metal material, such as aluminum or steel.

[0045] The housing 10 has a receiving cavity 11 and an opening 12 communicating with the receiving cavity 11. The cover plate 20 seals the opening 12 and is connected to the housing 10. The cover plate 20 has a first groove 21 and a through hole 22 communicating the first groove 21 and the receiving cavity 11. The first seal 30 is inserted through the through hole 22 and is in interference fit with the through hole 22. The first seal 30 has a connection groove 31 communicating with the receiving cavity 11, and the connection groove 31 is configured to increase the contact area between the first seal 30 and the internal gas of the receiving cavity 11. It can be understood that the receiving cavity inside the housing 10 can be used to accommodate the wound core electrode group of the battery. Then, by covering and sealing the opening of the housing 10 with the cover plate 20, the housing 10 can be closed, playing a role in protecting the internal structure of the battery. In order to quickly discharge the gas generated inside the battery and relieve the pressure inside the battery in extreme cases such as thermal runaway of the battery, a through hole 22 can be provided on the cover plate 20, and the through hole 22 is sealed by the first seal 30. The first seal 30 is inserted through the through hole and is in interference fit with the inner wall of the through hole 22, so that the first seal 30 is in close contact with the inner wall of the through hole 22, preventing the electrolyte inside the battery receiving cavity 11 from leaking through the through hole 22. The interference fit between the first seal 30 and the inner wall of the through hole 22 forms an explosion-proof structure. Compared with the original scored explosion-proof valve (due to the cover plate material and processing errors, the original scored explosion-proof valve may have relatively high strength and hardness, resulting in a large error between the actual opening pressure and the preset opening pressure, and the battery cannot open the valve and relieve pressure in time in extreme cases), the connection strength between the first seal 30 and the inner wall of the through hole 22 is generally less than the strength of the score, so this structure has higher opening accuracy. When the battery undergoes extreme conditions such as thermal runaway, a large amount of gas will be rapidly generated, causing the internal pressure of the battery to continuously increase. When the internal pressure reaches the preset pressure, the gas inside the battery can quickly extrude the first seal out of the inside of the through hole, enabling the battery to relieve pressure through the through hole and preventing the battery from exploding.

[0046] Meanwhile, a connection groove 31 communicating with the accommodation cavity 11 is provided on the first seal 30. When the battery undergoes thermal runaway, part of the gas in the accommodation cavity 11 can enter the connection groove 31, increasing the contact area between the first seal 30 and the gas. The gas entering the connection groove 31 can squeeze the inner wall of the connection groove 31. Since the gas is fluid, the direction of the force acting on the inner wall of the connection groove 31 is the same as the direction of the height direction X and some intersects with the direction of the height direction X. For this force intersecting with the direction of the height direction X, there will also be some component forces along the height direction X, which can help push the first seal 30, making it easier for the gas to push the first seal 30. When the battery undergoes thermal runaway, the through hole 22 is easier to open, further improving the valve opening accuracy of the explosion-proof structure. The size of the inner wall area of the connection groove 31 can be set as needed. By changing the size of its inner wall area, the opening pressure of the battery can be adjusted.

[0047] Please refer to Figure 6 and Figure 7 , in combination with the above embodiments, in some embodiments, the inner wall of the connection groove 31 is an arc surface or a spherical surface. It can be understood that the inner wall surface of the connection groove 31 can be set as a spherical surface. As Figure 6 shown, this structure can increase the contact area between the first seal 30 and the gas inside the battery. At the same time, when the gas acts on the spherical surface, a part of the force can push the first seal 30 along the height direction X under the action of the spherical surface, which can increase the thrust of the gas on the first seal 30, facilitating the first seal 30 to be promptly pushed out of the inside of the through hole 22, and is conducive to the battery to release pressure in a timely manner. The inner wall surface of the connection groove 31 can also be set as an arc surface. As Figure 7 shown, the dotted part in the figure is the part of the connection groove 31 that is blocked. The connection groove 31 can be regarded as formed by combining two cavities. One cavity is a cylindrical structure, and the other cavity is a conical structure. The inner wall of the connection groove 31 formed by combining these two cavities is an arc surface. While increasing the contact area between the first seal 30 and the gas, the arc surface can also decompose the force acting on it by the gas, so that a part of the component force pushes the inner wall of the connection groove 31 outward along the height direction X. When the battery has a thermal runaway, it is easier to push the first seal 30 out of the inside of the through hole 22, enabling the battery to exhaust gas and release pressure through the through hole 22 in a timely manner.

[0048] Please refer to Figure 8 , in combination with the above embodiments, in some embodiments, the inner wall of the connection groove 31 includes a plurality of planes, and two adjacent planes are connected to each other and are inclined to each other. It can be understood that, as Figure 8As shown, the dashed part in the figure is the part of the connecting groove 31 that is blocked. The inner wall of the connecting groove 31 is composed of multiple planes. Two adjacent planes are connected to each other and are inclined to form a certain angle between two adjacent planes, so as to form the connecting groove 31 that can accommodate a certain amount of gas. Among these planes, the extending direction of at least one plane intersects with the top surface or the bottom surface of the first seal 30. After the gas generated by the thermal runaway of the battery enters the inside of the connecting groove 31, this plane can increase the contact area between the first seal 30 and the gas, and at the same time, it is convenient to decompose the acting force of the gas on this plane, so that a part of the component force pushes the inner wall of the connecting groove 31 along the height direction X. When the battery has a thermal runaway, it is easier to push the first seal 30 out of the inside of the through hole 22, so that the battery can exhaust gas and relieve pressure in time through the through hole 22. Of course, a part of the inner wall of the connecting groove 31 can be set as a plane, and the other part can be set as an arc surface, which can be set according to needs.

[0049] Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 Combined with the above embodiments, in some embodiments, the first seal 30 is a flexible structure. The first seal 30 includes a first main body portion 32, a second main body portion 33, and a folding portion 34.

[0050] The first main body portion 32 is disposed in the first groove 21. The second main body portion 33 is connected to the first main body portion 32. The second main body portion 33 passes through the through hole 22 into the accommodating cavity 11 and is in interference fit with the through hole 22. The connecting groove 31 is opened on the side of the second main body portion 33 away from the first main body portion 32. The folding portion 34 is located in the accommodating cavity 11 and is connected to the second main body portion 33. The folding portion 34 surrounds the second main body portion 33 and extends in a direction away from the connecting groove 31 along the radial direction of the second main body portion 33. It can be understood that the first seal 30 is a flexible structure and can be made of materials such as rubber and silica gel, having good deformation ability. When the first seal 30 is in interference fit with the through hole 22, the first seal 30 can be closely attached to the inner wall of the through hole 22 to prevent gaps from appearing between the two, improving the sealing effect of the electrolyte. At the same time, when the gas pushes the first seal 30, due to its certain deformation ability, it is easier to be pushed out of the inside of the through hole 22.

[0051] The first main body portion 32 on the first seal 30 is disposed within the first groove 21, the second main body portion 33 passes through the through hole 22, and the opening of the connecting groove 31 is disposed on the side of the second main body portion 33 facing away from the first main body portion 32. The depth at which the connecting groove 31 is formed can be set as needed, and it can be formed only on the second main body portion 33 or extend from the second main body portion 33 into the interior of the first main body portion 32. The folding portion 34 is disposed around the second main body portion 33 and extends radially away from the connecting groove 31 along the second main body portion 33, which can improve the stability of the connection between the first seal 30 and the cover plate 20 to a certain extent, and prevent the first seal 30 from being easily pushed out of the interior of the through hole 22 due to poor interference fit ability between the first seal 30 and the through hole 22. If a higher valve opening pressure needs to be set, the folding portion 34 can be provided on the second main body portion 33. When thermal runaway occurs inside the battery, the generated gas will push the second main body portion 33, and the folding portion 34 can play a certain role in blocking the movement of the second main body portion 33. At the same time, if the through hole 22 needs to be opened, the folding portion 34 and the second main body portion 33 need to be pushed out through the through hole 22 at the same time. The sum of the volumes of the folding portion 34 and the second main body portion 33 is relatively large, and a greater force is required for pushing. Therefore, for a battery that needs to set a relatively large valve opening pressure, the folding portion 34 can be provided on the second main body portion 33 to increase the opening pressure of the explosion-proof structure, and can also play a role in adjusting the opening pressure of the explosion-proof structure to a certain extent.

[0052] Please refer to Figure 4 、 Figure 6 and Figure 9 In combination with the above embodiments, in some embodiments, an inclined surface 341 is provided on the outer periphery of the folding portion 34. Along the radial direction of the second main body portion 33 and away from the connecting groove 31, the minimum distance from the inclined surface 341 to the cover plate 20 gradually decreases. It can be understood that in order to facilitate the interference fit between the first seal 30 and the through hole 22, that is, to facilitate the first seal 30 to penetrate through the through hole 22, a chamfer structure can be provided on the folding portion 34. That is, an inclined surface 341 is provided on the outer periphery of the folding portion 34. Along the radial direction of the second main body portion 33 and away from the connecting groove 31, the minimum distance from the inclined surface 341 to the cover plate 20 gradually decreases. For such an inclined surface 341 in an inclined form, when the first seal 30 penetrates through the through hole 22, it can play a certain guiding role in guiding the second main body portion 33 to penetrate through the through hole 22. At the same time, by setting the folding portion 34 in this form, the folding portion 34 can more easily pass through the through hole 22, which can reduce the installation difficulty of the first seal 30 and reduce the time spent on installation.

[0053] Please refer to Figure 4, in combination with the above embodiments, in some embodiments, the first groove 21 has a side wall 211, and the side wall 211 is inclined with respect to the height direction X; along a direction perpendicular to the height direction X, there is a spacing D between the first main body portion 32 and the side wall 211, and in the direction in which the first main body portion 32 faces away from the second main body portion 33, the spacing D gradually increases. It can be understood that when the electrolyte inside the battery needs to be replenished, the electrolyte can be poured through the through hole 22, so it is necessary to take out the first seal 30 from the inside of the first groove 21 and the through hole 22. By setting the side wall 211 of the first groove 21 to an inclined structure, and the spacing D between the first main body portion 32 and the side wall 211 gradually increases in the direction in which the first main body portion 32 faces away from the second main body portion 33, the first groove 21 is in a horn-shaped structure. During the process of taking out the first seal 30, since the opening space of the first groove 21 is relatively large, it is convenient for the user's finger or a tool to be inserted into the inside of the first groove 21 to contact the outer peripheral side of the first main body portion 32, and it is convenient to pull the first main body portion 32 by squeezing the outer peripheral side of the first main body portion 32, so as to take out the entire first seal 30 from the inside of the through hole 22 and the first groove 21. The outer peripheral side of the first main body portion 32 can be provided with a concavo-convex structure, which can increase the friction force of the finger or the tool, and is beneficial to quickly bend and fold the outer peripheral side of the first main body portion 32, facilitating pulling the outer peripheral side of the first main body portion 32 to take out the entire first seal 30, and improving the efficiency of taking out.

[0054] Please refer to Figure 10 , Figure 11 , Figure 12 and Figure 14 , in combination with the above embodiments, in some embodiments, the single battery includes: a second seal 40. The second seal 40 covers the first groove 21 and is connected to the cover plate 20. It can be understood that after the first seal 30 is arranged on the cover plate 20, the second seal 40 can be arranged on the cover plate 20, so that the second seal 40 can cover the first groove 21 where the first seal 30 is located. The periphery of the second seal 40 is welded to the cover plate 20, and the through hole 22 can be secondarily sealed. Even if the electrolyte inside the battery leaks into the first groove 21 through the through hole 22, the second seal 40 can block these leaked electrolytes and prevent them from leaking to the outside of the battery, further improving the sealing effect of the battery. The second seal 40 can be a thin aluminum sheet welded to the cover plate 20.

[0055] Since the cylindrical battery core electrode group occupies a large proportion inside the housing and can accommodate relatively little electrolyte itself (and taking the current 4680 large cylindrical battery as an example, due to the cylindrical housing, it has a good tolerance for gas production. When using materials such as 9-series high-nickel for the positive electrode, the nickel content is high and the activity is high, and it is very easy to have side reactions with the electrolyte, consuming the electrolyte), therefore, electrolyte dryness is likely to occur in the later stage of cycling, resulting in a reduction or termination of the battery cycle life, and the battery cannot be used or recycled in a stepped manner. The structure in this application facilitates the replenishment of electrolyte for the cylindrical battery. When the battery needs to replenish electrolyte, the welded second seal 40 can be removed, the first seal 30 can be taken out through a tool, and then electrolyte can be added to the inside of the battery through the through hole 22. This structure enables the battery to have the function of replenishing electrolyte multiple times, can improve the service life of the battery, and makes it possible to recycle the battery in a stepped manner. At the same time, it has the functions of maintainability and performance repair, that is: the old electrolyte can be replaced at any time according to the battery condition, extending the cycle life of the lithium battery, reducing the frequency of replacing waste batteries at the same time, and reducing resource waste. After the electrolyte replenishment is completed, the first seal 30 is inserted, and a new second seal 40 is re-welded. In order to ensure the sealing performance, the welding track of the second seal 40 needs to be polished, or the weld bead of the secondary welding of the second seal 40 avoids the first weld bead, which can ensure the stability of the welding.

[0056] Please refer to Figure 11 、 Figure 12 and Figure 13 Combined with the above embodiments, in some embodiments, the cover plate 20 has a second groove 23 communicating with the first groove 21. The second seal 40 is disposed in the second groove 23. The dimension of the second groove 23 in the height direction X of the housing 10 is L1, and the dimension of the second seal 40 in the height direction X is L2, satisfying: L1≥L2. It can be understood that the middle part of the cover plate 20 presents a concave structure relative to the edge. This concave structure forms the second groove 23. The second groove 23 communicates with the first groove 21, and the opening of the second groove 23 is larger than the opening of the first groove 21. Since the second seal 40 needs to cover and seal the first groove 21, the second seal 40 can be disposed inside the second groove 23. The dimension L1 of the second groove 23 in the height direction X being greater than or equal to the dimension L2 of the second seal 40 in the height direction X can enable the cover plate 20 to play a certain protective role for the second seal 40. When a relatively large object collides with the cover plate 20, to a large extent, it will first contact the relatively protruding peripheral structure of the cover plate 20, and the peripheral structure of the cover plate 20 bears the acting force, avoiding the object from colliding with the second seal 40 and causing damage to the second seal 40.

[0057] Please refer to Figure 10 、 Figure 11 and Figure 14, in combination with the above embodiments, in some embodiments, the cover plate 20 includes an inner circular portion 24 and an outer circular portion 25. The outer circular portion 25 is disposed around the inner circular portion 24. The inner side of the outer circular portion 25 is connected to the inner circular portion 24, and the outer side of the outer circular portion 25 is connected to the housing 10. A first groove 21 and a through hole 22 are provided on the inner circular portion 24. The second seal 40 covers and seals the first groove 21 and the through hole 22 and is connected to the inner circular portion 24. The cover plate 20 further includes a notch 26. The notch 26 is disposed between the inner circular portion 24 and the outer circular portion 25 and is respectively connected to the inner circular portion 24 and the outer circular portion 25. At least a part of the notch 26 is an arc-shaped structure.

[0058] It can be understood that the inner circular portion 24 can be a circular structure, and the outer circular portion 25 can be an annular structure. The outer circular portion 25 is disposed around the outer periphery of the inner circular portion 24, so that the inner side of the outer circular portion 25 can be connected to the inner circular portion 24, and the outer side can be connected to the housing 10, thereby covering and sealing the housing 10 of the battery through the inner circular portion 24 and the outer circular portion 25. A second groove 23 is formed by inward depression in the middle of the inner circular portion 24. A first groove 21 can be formed by inward depression in the middle of the second groove 23. The first groove 21 communicates with the second groove 23 (the inner diameter of the first groove 21 is smaller than the inner diameter of the second groove 23). A through hole 22 can be provided on the bottom wall of the first groove 21 (the inner diameter of the through hole 22 is smaller than the inner diameter of the first groove 21), so that the first groove 21 communicates with the accommodation cavity 11 of the battery through the through hole 22. The through hole 22 can be blocked by the first seal 30. The second seal 40 disposed in the second groove 23 can cover and seal the first groove 21 and the through hole 22, and can play a certain protective role for the first seal 30 inside the first groove 21. A notch 26 can also be provided on the cover plate 20. The notch 26 is disposed between the inner circular portion 24 and the outer circular portion 25. The thickness of the notch 26 is small. When the internal pressure of the battery increases, the notch 26 is prone to breakage, so that the inner circular portion 24 is lifted, and the accommodation cavity 11 inside the battery is connected to the external environment, thereby releasing the pressure inside the battery. This setting method enables the battery to have a two-stage explosion-proof structure. The first seal 30 and the through hole 22 are the first-stage explosion-proof structure, and the notch 26 and the inner circular portion 24 are the second-stage explosion-proof structure. Through the combined setting of the first seal 30 and the through hole 22, it can be accurately opened according to the preset pressure inside the battery, and the opening stability is relatively high. When the internal pressure of the battery is too high, the inner circular portion 24 can be opened through the notch 26, and the internal pressure of the thermally out-of-control battery can be quickly released, making the battery safety more guaranteed.

[0059] A battery pack includes the single cells described above. A battery pack is an integrated whole composed of multiple single cells, and generally includes components such as battery cells, a battery management system (BMS), connectors, and a protective housing. Its main function is to provide higher voltage, capacity, and energy density to meet the requirements of various applications. Battery packs are usually applied in fields such as electric vehicles, drones, portable electronic devices, energy storage systems, and emergency power supplies.

[0060] In the above embodiments, the descriptions of the respective embodiments have their own focuses. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0061] The single cells and battery packs provided by the embodiments of the present application have been introduced in detail above, and specific examples have been used to elaborate on the principle and implementation manner of the present application. The descriptions of the above embodiments are only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A single cell battery, characterized in that: include: A housing having a receiving cavity and an opening communicating with the receiving cavity; A cover plate, covering the opening and connected to the housing, wherein the cover plate has a first groove and a through hole connecting the first groove and the accommodating cavity; The first sealing member is passed through the through hole and is interference fit with the through hole. The first sealing member has a connecting groove connected to the accommodating cavity. The connecting groove is configured to increase the contact area between the first sealing member and the gas inside the accommodating cavity.

2. The single cell according to claim 1, characterized in that: The inner wall of the connecting groove is an arc surface or a spherical surface.

3. The single cell according to claim 1, characterized in that: The inner wall of the connecting groove includes a plurality of planes, and two adjacent planes are connected to each other and inclined to each other.

4. The single cell according to claim 1, characterized in that: The first sealing member is a flexible structure; the first sealing member comprises: A first main body portion, disposed in the first groove; A second main body portion is connected to the first main body portion, the second main body portion is passed through the through hole to the accommodating cavity and is interference fit with the through hole, and the connecting groove is provided on a side of the second main body portion away from the first main body portion; The folding portion is located in the accommodating cavity and connected to the second main body portion. The folding portion is arranged around the second main body portion and extends in a radial direction of the second main body portion toward a direction away from the connecting groove.

5. The single cell according to claim 4, characterized in that: An inclined surface is disposed on the outer periphery of the folded portion, and a minimum distance from the inclined surface to the cover plate gradually decreases along the radial direction of the second main body portion toward a direction away from the connecting groove.

6. The single cell according to claim 4, characterized in that: The first groove has a side wall, and the side wall is arranged obliquely in the height direction; Along a direction perpendicular to the height direction, there is a distance D between the first main body portion and the side wall, and the distance D gradually increases in a direction in which the first main body portion departs from the second main body portion.

7. The single cell according to claim 4, characterized in that: The single cell battery comprises: A second sealing member is provided, wherein the second sealing member seals the first groove and is connected to the cover plate.

8. The single cell according to claim 7, characterized in that: The cover plate has a second groove connected to the first groove, the second seal is arranged in the second groove, the size of the second groove in the height direction of the shell is L1, the size of the second seal in the height direction is L2, and the following is satisfied: L1≥L2.

9. The single cell according to claim 7, characterized in that: The cover plate includes an inner circular portion and an outer circular portion, the outer circular portion is arranged around the inner circular portion, the inner side of the outer circular portion is connected to the inner circular portion, the outer side of the outer circular portion is connected to the housing, the inner circular portion is provided with the first groove and the through hole, the second sealing member covers the first groove and the through hole, and is connected to the inner circular portion; The cover plate further comprises a notch, which is arranged between the inner circular portion and the outer circular portion and is respectively connected to the inner circular portion and the outer circular portion, and at least a portion of the notch is an arc-shaped structure.

10. A battery pack, characterized in that: Comprising a single cell as claimed in claims 1 to 9.

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