Battery pack and electric equipment

Abstract

The invention relates to a battery pack and electric equipment. The battery pack comprises a supporting component and a battery monomer which are sequentially arranged along a first direction, the battery monomer is provided with an anti-explosion valve, and the anti-explosion valve comprises a main body part, a valve port formed in the main body part and an anti-explosion sheet; the anti-explosion piece is used for shielding the valve port and comprises an annular part and a middle part, the outer periphery of the annular part is connected to the main body part, the inner periphery of the annular part is connected with the outer periphery of the middle part, and the middle part is arranged to be capable of being separated from the annular part when the battery monomers are in thermal runaway; an avoiding opening is formed in the supporting part and corresponds to the valve opening; the distance between the outer periphery of the annular part and the inner periphery of the annular part is a first distance, in the first direction, the shortest distance between the annular part and the receding opening is a second distance, and the first distance is smaller than the second distance. The annular part is bent and deformed towards the supporting part under the action of the gas of the battery monomer, and cannot be in contact with the avoiding opening.

Description

Technical Field

[0001] This disclosure relates to the field of battery pack technology, and more particularly to a battery pack and an electrical device. Background Technology

[0002] A battery pack is a device used to provide energy to electrical equipment and is a core component of such equipment. The battery pack of a new energy vehicle contains individual battery cells. The explosion-proof valves of these cells and the clearance openings of the supporting components are connected and face towards the bottom of the vehicle. This ensures that in the event of thermal runaway of a battery cell, fumes and other substances are discharged towards the bottom of the vehicle, ensuring the safety of the occupants.

[0003] In related technologies, when a battery cell experiences thermal runaway, it is prone to short-circuiting with the supporting components, which can lead to insulation failure of the battery pack and thermal propagation, thus affecting the safety of the battery pack. Summary of the Invention

[0004] The purpose of this disclosure is to provide a battery pack and electrical device that at least partially solves the aforementioned technical problems.

[0005] To achieve the above objectives, according to a first aspect of this disclosure, a battery pack is provided, including a support member and a battery cell arranged sequentially along a first direction; The battery cell has an explosion-proof valve, which includes a main body, a valve port disposed on the main body, and an explosion-proof plate. The explosion-proof sheet is used to block the valve port and includes an annular portion and a middle portion. The outer periphery of the annular portion is connected to the main body portion, and the inner periphery of the annular portion is connected to the outer periphery of the middle portion. The middle portion is configured to be able to separate from the annular portion in the event of thermal runaway of the battery cell. The support component is provided with a clearance opening, which is arranged correspondingly to the valve port; The distance between the outer periphery of the annular portion and the inner periphery of the annular portion is the first distance, and the shortest distance between the annular portion and the clearance opening in the first direction is the second distance, wherein the first distance is less than the second distance.

[0006] Optionally, in the height direction of the battery pack, the support member is located at the bottom of the battery cell; The second distance is the height difference between the annular portion and the upper surface of the clearance opening.

[0007] Optionally, the intermediate portion is provided with at least one weak portion, the structural strength of the weak portion is less than the structural strength of other parts of the intermediate portion, and / or the melting point of the weak portion is lower than the melting point of other parts of the intermediate portion, so that the intermediate portion can be separated into multiple parts under the action of the gas of the battery cell.

[0008] Optionally, the weak point is constructed as a notch.

[0009] Optionally, there are multiple weak points, and the multiple weak points are arranged at intervals on the middle part along at least one preset trajectory.

[0010] Optionally, the plurality of weak points on each of the preset trajectories are symmetrical about the centerline of the length direction of the middle part or the centerline of the width direction of the middle part.

[0011] Optionally, the at least one preset trajectory includes a first trajectory and a second trajectory, wherein the first trajectory and the second trajectory are symmetrical about the centerline in the length direction or the centerline in the width direction of the middle portion.

[0012] Optionally, both the first trajectory and the second trajectory are arc-shaped trajectories; The convex direction of the first trajectory is opposite to that of the second trajectory.

[0013] Optionally, the at least one preset trajectory includes a first trajectory and a second trajectory, wherein the first trajectory and the second trajectory are constructed as a cross-shaped trajectory; the center of the cross-shaped trajectory coincides with the center of the middle part.

[0014] Optionally, there may be multiple weak points, which are arranged in an array on the middle portion.

[0015] Optionally, the connection strength between the inner periphery of the annular portion and the outer periphery of the intermediate portion is lower than the strength of the intermediate portion.

[0016] Optionally, the inner periphery of the annular portion and the outer periphery of the middle portion are connected by a plurality of connecting portions, and the plurality of connecting portions are arranged at intervals. The number of the grooves is multiple, and the multiple grooves are arranged at intervals on the middle part, with the interval between each two adjacent connecting parts being greater than the minimum distance between any two adjacent grooves.

[0017] Optionally, the annular portion and the intermediate portion are integrally formed.

[0018] Optionally, the support component includes a liquid cooling plate located at the bottom of the battery cell, and the liquid cooling plate is provided with the clearance opening.

[0019] According to a second aspect of this disclosure, an electrical appliance is provided, including the battery pack described above.

[0020] The above technical solution isolates the internal structure of the battery cell from the external environment by using the annular portion and the middle portion to jointly block the valve port. When the battery cell experiences thermal runaway, the middle portion can separate from the annular portion, allowing the gas and substances inside the battery cell to escape through the valve port. Since the first distance is less than the second distance—that is, the distance between the outer and inner circumferences of the annular portion is less than the shortest distance between the annular portion and the clearance port in the first direction—even if the annular portion bends and deforms towards the support component under the influence of the gas in the battery cell during thermal runaway, it will not come into contact with the clearance port. This helps reduce the risk of short circuit between the battery cell and the support component during thermal runaway and helps prevent thermal propagation of the battery pack due to short circuits, thereby improving the safety of the battery pack. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0022] Figure 1 This is an exploded view of a battery pack provided in one embodiment of this disclosure.

[0023] Figure 2 This is a cross-sectional schematic diagram of a battery pack provided in one embodiment of this disclosure.

[0024] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0025] Figure 4 This is a bottom view of a battery cell provided in one embodiment of the present disclosure.

[0026] Figure 5 This is a schematic diagram of the structure of the explosion-proof sheet provided in some embodiments of this disclosure.

[0027] Figure 6 This is a schematic diagram of the structure of the explosion-proof sheet provided in some embodiments of this disclosure.

[0028] Figure 7 This is a schematic diagram of the structure of the explosion-proof sheet provided in some embodiments of this disclosure.

[0029] Figure 8 This is a schematic diagram of the structure of the explosion-proof sheet provided in some embodiments of this disclosure.

[0030] Explanation of reference numerals in the attached figures 100-Battery pack; 10-Battery cell; 20-Explosion-proof valve; 21-Main body; 22-Valve port; 30-Explosion-proof plate; 31-Annular part; 32-Middle part; 321-Weak part; 33-Connecting part; 40-Supporting component; 41-Clearing opening; 51-Bottom plate of battery casing; 52-Frame of battery casing; 53-Top cover of battery casing; 61-Centerline of the length direction of the middle part; 62-Centerline of the width direction of the middle part; 71-First trajectory; 72-Second trajectory. Detailed Implementation

[0031] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0032] In this disclosure, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally defined as the upper, lower, top, and bottom of the battery pack in its normal operating state. They are used solely for the convenience of describing this disclosure and for simplification, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or a specific orientational construction and operation. Therefore, they should not be construed as limitations on this disclosure. "Inner" and "outer" refer to the inner and outer contours of the corresponding components. "First direction" and "second direction" can be found in [reference needed]. Figure 3 The first and second directions shown are used, and the terms "first," "second," etc., are used to distinguish one element from another and do not have any order or importance.

[0033] In the description of this disclosure, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "connect," "link," and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0034] Research has found that, in related technologies, the reason why battery cells are prone to short-circuiting with supporting components when thermal runaway occurs is partly due to the fact that safety valves are usually equipped with explosion-proof discs to isolate the inside of the battery cell from the external environment and prevent mutual influence between the internal and external environments. However, when a battery cell experiences thermal runaway, the gas generated inside the cell not only breaks through the explosion-proof disc, but also causes the portion of the explosion-proof disc remaining at the valve port to bend and deform towards the supporting component (such as a liquid cooling plate). This results in a short circuit between the battery cell and the clearance port, causing insulation failure in the battery pack and leading to thermal propagation, which affects the safety of the battery pack.

[0035] In view of this, such as Figures 1 to 8As shown, according to a first aspect of this disclosure, a battery pack 100 is provided, including a support member 40 and a battery cell 10 arranged sequentially along a first direction. The battery cell 10 has an explosion-proof valve 20, which includes a main body 21, a valve port 22 disposed on the main body 21, and an explosion-proof sheet 30. The explosion-proof sheet 30 is used to block the valve port 22 and includes an annular portion 31 and a middle portion 32. The outer periphery of the annular portion 31 is connected to the main body 21, and the inner periphery of the annular portion 31 is connected to the outer periphery of the middle portion 32. The middle portion 32 is configured to separate from the annular portion 31 in the event of thermal runaway of the battery cell 10. The support member 40 is provided with a clearance port 41, which is arranged correspondingly to the valve port 22 and can be used to allow gas from the explosion-proof valve 20 to pass through. The distance between the outer periphery of the annular portion 31 and the inner periphery of the annular portion 31 is a first distance, and the shortest distance between the annular portion 31 and the clearance port 41 in the first direction is a second distance. The first distance is less than the second distance.

[0036] Through the above technical solution, the annular portion 31 and the middle portion 32 can jointly block the valve port 22, thus isolating the interior of the battery cell 10 from the external environment. When the battery cell 10 experiences thermal runaway, the middle portion 32 can separate from the annular portion 31. For example, under the action of gas during thermal runaway of the battery cell 10 (such as gas impact or high temperature), the middle portion 32 can separate from the annular portion 31, allowing the gas and substances inside the battery cell 10 to be discharged through the valve port 22. Since the first distance is smaller than the second distance, that is, the distance between the outer periphery of the annular portion 31 and the inner periphery of the annular portion 31 is smaller than the shortest distance between the annular portion 31 and the clearance opening 41 in the first direction, when the battery cell 10 experiences thermal runaway, even if the annular portion 31 bends and deforms towards the support member 40 under the action of the gas in the battery cell 10, the annular portion 31 will not come into contact with the clearance opening 41 (such as the inner wall of the clearance opening 41). This helps to reduce the risk of short circuit between the battery cell 10 and the support member 40 when thermal runaway occurs, and helps to avoid the thermal propagation phenomenon of the battery pack 100 caused by short circuit, thereby improving the safety of the battery pack 100.

[0037] Furthermore, since the annular portion 31 can reduce the risk of short circuit between the battery cell 10 and the inner wall of the clearance opening 41 in the event of thermal runaway, it also helps to reduce the insulation requirements of the inner wall of the clearance opening 41.

[0038] It is understood that the outer periphery of the annular portion 31 can be connected to the main body portion 21 through the inner wall of the valve port 22, or it can be connected to other parts of the main body portion 21. For example, the outer periphery of the annular portion 31 can also be connected to the main body portion 21 through the end of the valve port 22. This disclosure does not limit this.

[0039] Here, the axial cross-section of the annular portion 31 can be circular or other shapes, such as square, polygon, etc.

[0040] In this disclosure, the support member 40 can be supported at any position of the battery cell 10, and this disclosure does not limit this. As one embodiment, such as Figure 1 and Figure 3 As shown, in the height direction of the battery pack 100, the support member 40 is located at the bottom of the battery cell 10, and the second distance is the height difference between the annular portion 31 and the upper end face of the clearance opening 41. That is, the first direction can be the height direction of the battery pack 100. For example, when the battery pack 100 is used in a vehicle, the first direction can be the height direction of the vehicle. This arrangement facilitates the placement of the other battery cells 10 facing the bottom of the vehicle, thereby helping to ensure the safety of the occupants. The radial direction of the clearance opening 41 can be the second direction.

[0041] It is understandable that the bottom of the battery cell 10 refers to the bottom of the battery cell 10 in the battery pack 100 when in use. For example, when the battery pack 100 is used in a vehicle, the bottom of the battery cell 10 is the part of the battery cell 10 that is close to the ground, and the top of the battery cell 10 is the part of the battery cell 10 that is away from the ground.

[0042] To reduce the risk of blocked discharge from explosion-proof valve 20, as one implementation method, such as Figures 5 to 8 As shown, at least one weak portion 321 is provided on the intermediate portion 32. The structural strength of the weak portion 321 is less than that of the other parts of the intermediate portion 32, and / or the melting point of the weak portion 321 is lower than that of the other parts of the intermediate portion 32, so that the intermediate portion 32 can separate into multiple parts under the action of the gas generated when the battery cell 10 experiences thermal runaway. Since at least one weak portion 321 is provided on the intermediate portion 32, under the action of the gas generated when the battery cell 10 experiences thermal runaway, the weak portion 321 can be broken by the impact of the gas and / or melted by the high temperature of the gas, so that the intermediate portion 32 will not only separate from the annular portion 31, but also separate into multiple parts on its own. This helps to prevent the intermediate portion 32 from being stuck by the structure inside the battery pack 100, and thus helps to reduce the risk of obstruction of the discharge of the explosion-proof valve 20 (such as a reduction in the flow area of ​​the avoidance port 41).

[0043] In this disclosure, the weak part 321 can be constructed in any suitable structure, as one embodiment, such as Figures 5 to 8 As shown, the weak part 321 can be constructed as a notch. The notch is easy to process on the sheet-like middle part 32, and the notch can be processed at any position on the middle part 32 as needed, which is beneficial to control the shape of the middle part 32 after separation.

[0044] As another embodiment of this disclosure, the weak portion 321 may be constructed as a thickness-reduced portion, that is, the thickness of the location where the weak portion 321 is located is thinner than the thickness of other locations of the intermediate portion 32.

[0045] Optionally, such as Figures 5 to 8 As shown, the grooves can be constructed to penetrate the thickness direction of the middle portion 32 on both opposite sides of the middle portion 32. This allows gas inside the battery cell 10 to escape through the grooves, thus facilitating a smoother pressurization process inside the battery cell 10 in the event of thermal runaway. This prevents the battery cell 10 from exploding due to excessively rapid pressure increases, thereby improving the safety of the battery pack 100.

[0046] In this disclosure, the weak points 321 can be arranged on the intermediate portion 32 in any suitable manner as needed, and this disclosure does not limit this. As one embodiment, there can be multiple weak points 321, which are arranged at intervals along at least one preset trajectory on the intermediate portion 32. This arrangement allows the intermediate portion 32 to break into multiple parts along the preset trajectory under the action of gas in the battery cell 10. Thus, by designing the preset trajectory, the controllability of the shape of the fragments separated from the intermediate portion 32 can be improved. Furthermore, the interval arrangement of multiple weak points 321 helps to ensure the rigidity of the explosion-proof sheet 30 when the battery cell 10 does not experience thermal runaway.

[0047] As another embodiment of this disclosure, the weak portion 321 may also extend continuously along a preset trajectory on the middle portion 32.

[0048] Optionally, such as Figure 5 and Figure 6 As shown, the multiple weak points 321 on each preset trajectory are symmetrical about the centerline 61 in the length direction or the centerline 62 in the width direction of the middle part 32. Since the middle part 32 can break along the preset trajectory under the action of the gas in the battery cell 10, this arrangement helps to make the fragments broken off from the middle part 32 along the preset trajectory more uniform.

[0049] Optionally, such as Figure 5 and Figure 6 As shown, at least one preset trajectory includes a first trajectory 71 and a second trajectory 72, and the first trajectory 71 and the second trajectory 72 are symmetrical about the centerline 61 in the length direction of the middle portion 32 or the centerline 62 in the width direction of the middle portion 32.

[0050] Since the middle part 32 can break along the first trajectory 71 and the second trajectory 72 under the action of the gas in the battery cell 10, the first trajectory 71 and the second trajectory 72 are symmetrical about the center line 61 of the length direction of the middle part 32 or the center line 62 of the width direction of the middle part 32. This makes the fragments formed after the middle part 32 breaks symmetrical about the center line 61 of the length direction of the middle part 32 or about the center line 62 of the width direction of the middle part 32, which is beneficial to improving the uniformity of the fragments formed after the middle part 32 breaks.

[0051] This disclosure does not limit the shape and positional relationship of the first trajectory 71 and the second trajectory 72. As one embodiment, such as Figure 5 As shown, both the first trajectory 71 and the second trajectory 72 are arc-shaped trajectories. That is, there are multiple weak points 321. Some of the multiple weak points 321 are arranged at intervals along the first trajectory 71 on the middle part 32, and other parts of the multiple weak points 321 are arranged at intervals along the second trajectory 72 on the middle part 32. The protrusion direction of the first trajectory 71 is opposite to that of the second trajectory 72. This arrangement is beneficial for the middle part 32 to separate fragments with arc-shaped outer edges under the action of the gas generated when the battery cell 10 experiences thermal runaway. Fragments with arc-shaped outer edges have good passage ability and are not easily stuck by the internal structure of the battery pack 100, nor are they easily scratched by the internal structure of the battery pack 100. For example, fragments with arc-shaped outer edges can pass well through the avoidance opening 41 and are not easily scratched by the insulating layer on the inner wall of the avoidance opening 41, thereby helping to reduce the risk of short circuit between the battery cell 10 and the support component 40.

[0052] Here, the protruding part of the first trajectory 71 and the protruding part of the second trajectory 72 can be set as the closest part between the first trajectory 71 and the second trajectory 72, or it can be set as the farthest part between the two. This disclosure does not limit this.

[0053] Optionally, such as Figure 6 As shown, at least one preset trajectory includes a first trajectory 71 and a second trajectory 72. The first trajectory 71 and the second trajectory 72 are constructed as a cross-shaped trajectory, with the center of the cross-shaped trajectory coinciding with the center of the middle part 32. That is, the intersection of the first trajectory 71 and the second trajectory 72 coincides with or is located near the central axis of the middle part 32. This arrangement facilitates the breakage of the middle part 32 into four uniformly sized fragments along the cross-shaped trajectory under the action of the gas generated when the battery cell 10 experiences thermal runaway. This helps to prevent any fragment of the middle part 32 from becoming too large and getting stuck in the internal structure of the battery pack 100.

[0054] In addition to the implementation methods described above, the preset trajectory may also extend along the width, length, or diagonal direction of the middle portion 32.

[0055] As another embodiment of this disclosure, such as Figure 7 and Figure 8 As shown, there are multiple weak points 321, which are arranged in an array on the middle part 32. This arrangement facilitates the separation of multiple fragments from the middle part 32 under the action of the gas generated when the battery cell 10 experiences thermal runaway. The size of the fragments can be controlled by adjusting the spacing between adjacent weak points 321.

[0056] Research has found that when a battery cell 10 experiences thermal runaway, if the intermediate portion 32 separates into multiple parts first, fragments of the intermediate portion 32 that have not separated from the annular portion 31 may approach the support member 40 due to the bending and deformation of the annular portion 31. This could result in the fragments of the intermediate portion 32 not being completely separated from the annular portion 31, blocking the valve port 22, or even short-circuiting with the support member 40. Therefore, as an implementation, the connection strength between the inner periphery of the annular portion 31 and the outer periphery of the intermediate portion 32 can be lower than the strength of the intermediate portion 32. This allows the intermediate portion 32 to separate from the annular portion 31 first under the influence of the gas generated during thermal runaway of the battery cell 10, and then separate into multiple parts itself. This helps reduce the risk of fragments of the intermediate portion 32 remaining attached to the annular portion 31, thereby reducing the risk of fragments of the intermediate portion 32 blocking the valve port 22 and short-circuiting with the support member 40.

[0057] Optionally, such as Figures 5 to 8 As shown, the inner periphery of the annular portion 31 and the outer periphery of the intermediate portion 32 are connected by multiple connecting portions 33. These connecting portions 33 are spaced apart, and multiple grooves are arranged at intervals on the intermediate portion 32. The distance between any two adjacent connecting portions 33 is greater than the minimum distance between any two adjacent grooves. Because the distance between any two adjacent connecting portions 33 is greater than the minimum distance between any two adjacent grooves, when the battery cell 10 experiences thermal runaway, the connecting portions 33 can break before the intervals between the grooves. That is, the intermediate portion 32 separates from the annular portion 31 first, and then separates into multiple parts. This helps reduce the risk of fragments of the intermediate portion 32 remaining attached to the annular portion 31, and further reduces the risk of the fragment blocking valve 22 of the intermediate portion 32 and short-circuiting with the support member 40.

[0058] In this disclosure, the annular portion 31 and the intermediate portion 32 can be integrally formed, or the annular portion 31 and the intermediate portion 32 can be formed separately and then connected. This disclosure does not limit this.

[0059] This disclosure does not limit the specific structure of the support component 40, such as Figure 1As shown, the support component 40 may include a liquid cooling plate located at the bottom of the battery cell 10, and the liquid cooling plate is provided with a clearance opening 41. The liquid cooling plate may be disposed at the bottom of the battery cell 10 for heat exchange with the battery cell 10, for example, for cooling and heating the battery cell 10.

[0060] The liquid cooling plate can be spaced apart from the bottom protective plate 51 of the battery casing to form an exhaust channel. This exhaust channel can be connected to the exhaust valve on the battery casing (such as the frame 52 of the battery casing). In this way, when the battery cell 10 experiences thermal runaway, the gas inside the battery cell 10 can be discharged to the outside of the battery pack 100 through the explosion-proof valve 20, the clearance port 41, the exhaust channel and the exhaust valve.

[0061] It is understandable that, such as Figure 1 As shown, the bottom protective plate 51 of the battery casing and the frame 52 of the battery casing can together form the tray of the battery casing. The tray of the battery casing and the top cover 53 of the battery casing can together enclose the battery cell 10 and the liquid cooling plate inside.

[0062] According to a second aspect of this disclosure, an electrical appliance is provided, including the battery pack 100 described above. The electrical appliance may further include an appliance body, the battery pack 100 being used to supply power to the appliance body.

[0063] Here, the electrical equipment can be a vehicle or any other equipment suitable for using the battery pack 100, and this disclosure does not limit it.

[0064] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0065] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0066] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A battery pack, characterized in that, It includes support components and battery cells arranged sequentially along the first direction; The battery cell has an explosion-proof valve, which includes a main body, a valve port disposed on the main body, and an explosion-proof plate. The explosion-proof sheet is used to block the valve port and includes an annular portion and a middle portion. The outer periphery of the annular portion is connected to the main body portion, and the inner periphery of the annular portion is connected to the outer periphery of the middle portion. The middle portion is configured to be able to separate from the annular portion in the event of thermal runaway of the battery cell. The support component is provided with a clearance opening, which is arranged correspondingly to the valve port; The distance between the outer periphery of the annular portion and the inner periphery of the annular portion is the first distance, and the shortest distance between the annular portion and the clearance opening in the first direction is the second distance, wherein the first distance is less than the second distance.

2. The battery pack according to claim 1, characterized in that, In the height direction of the battery pack, the support member is located at the bottom of the battery cell; The second distance is the height difference between the annular portion and the upper surface of the clearance opening.

3. The battery pack according to claim 1, characterized in that, At least one weak part is provided on the intermediate part, the structural strength of the weak part is less than the structural strength of the other parts of the intermediate part, and / or the melting point of the weak part is lower than the melting point of the other parts of the intermediate part, so that the intermediate part can be separated into multiple parts under the action of the gas of the battery cell.

4. The battery pack according to claim 3, characterized in that, The weak part is constructed by a notch.

5. The battery pack according to claim 3, characterized in that, The number of weak parts is multiple, and the multiple weak parts are arranged at intervals on the middle part along at least one preset trajectory.

6. The battery pack according to claim 5, characterized in that, The multiple weak points on each of the preset trajectories are symmetrical about the centerline of the length direction of the middle part or the centerline of the width direction of the middle part.

7. The battery pack according to claim 5, characterized in that, The at least one preset trajectory includes a first trajectory and a second trajectory, wherein the first trajectory and the second trajectory are symmetrical about the centerline in the length direction of the middle portion or the centerline in the width direction of the middle portion.

8. The battery pack according to claim 7, characterized in that, Both the first trajectory and the second trajectory are arc-shaped trajectories; The convex direction of the first trajectory is opposite to that of the second trajectory.

9. The battery pack according to claim 5, characterized in that, The at least one preset trajectory includes a first trajectory and a second trajectory, the first trajectory and the second trajectory being constructed as a cross-shaped trajectory; the center of the cross-shaped trajectory coincides with the center of the middle part.

10. The battery pack according to claim 3, characterized in that, The number of weak parts is multiple, and the multiple weak parts are arranged in an array on the middle part.

11. The battery pack according to any one of claims 1-10, characterized in that, The connection strength between the inner periphery of the annular portion and the outer periphery of the middle portion is lower than that of the middle portion.

12. The battery pack according to claim 4, characterized in that, The inner periphery of the annular portion and the outer periphery of the middle portion are connected by a plurality of connecting portions, which are arranged at intervals. The number of the grooves is multiple, and the multiple grooves are arranged at intervals on the middle part, with the interval between each two adjacent connecting parts being greater than the minimum distance between any two adjacent grooves.

13. The battery pack according to claim 12, characterized in that, The annular portion and the middle portion are integrally formed.

14. The battery pack according to any one of claims 1-10, characterized in that, The supporting component includes a liquid cooling plate located at the bottom of the battery cell, and the liquid cooling plate is provided with the clearance opening.

15. An electrical appliance, characterized in that, Includes the battery pack according to any one of claims 1-14.

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