Secondary battery, battery pack and electric device

Abstract

Disclosed in the present application are a secondary battery, a battery pack and an electric device. The secondary battery comprises a casing, an electrode assembly and a top cover assembly, wherein the casing has an accommodating cavity configured to accommodate the electrode assembly; the top cover assembly comprises a top cover plate and a lower insulating member, the top cover plate being connected to the casing and covering and sealing the accommodating cavity; the lower insulating member is connected between the top cover plate and the electrode assembly; the top cover plate is provided with a pressure relief member; the lower insulating member has a second recess, which is disposed on the side of the lower insulating member facing the electrode assembly and is in communication with the accommodating cavity; and the second recess has a second bottom wall, which is spaced apart from the pressure relief member, and the second bottom wall is configured to rupture when the internal pressure of the secondary battery reaches a threshold value, such that the internal pressure of the secondary battery directly acts on the pressure relief member. In the present application, the lower insulating member is provided with the second recess, the second bottom wall shields the top cover plate to reduce the exposed metal area of the top cover plate, and the second bottom wall ruptures to achieve normal pressure relief of the battery, thereby improving the safety of the secondary battery.

Description

Secondary batteries, battery packs and electrical devices

[0001] This application claims priority to Chinese Patent Application No. 202411452697.6, filed on October 17, 2024, entitled "Secondary Battery, Battery Pack and Electrical Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of battery technology, specifically relating to a secondary battery, a battery pack, and an electrical device. Background Technology

[0003] The top cover assembly of a secondary battery typically includes a lower insulating component under the top cover sheet, an explosion-proof valve mounted on the top cover sheet, and a vent hole positioned between the top cover sheet and the electrode assembly, opposite the explosion-proof valve. This vent hole directs gas to the explosion-proof valve in case of abnormal gas generation, causing the valve to open and release internal pressure, preventing battery explosion. However, electrode tabs or other metallic foreign objects may also come into contact with the explosion-proof valve through the vent hole, potentially causing an internal short circuit and posing a risk of corrosion and cracking of the explosion-proof valve. Summary of the Invention

[0004] This application provides a secondary battery to solve the problem of short circuits caused by tabs or other metallic foreign objects in existing batteries connecting to the explosion-proof valve through the vent hole of the lower insulator; another objective of this application is to provide a battery pack, and yet another objective is to provide an electrical device.

[0005] Technical solution: A secondary battery according to an embodiment of this application includes:

[0006] The shell has a receiving cavity;

[0007] Electrode assembly is disposed in the receiving cavity;

[0008] A top cover assembly includes a top cover sheet and a lower insulating member. The top cover sheet is connected to the housing and seals the receiving cavity. The lower insulating member is disposed between the top cover sheet and the electrode assembly, and is connected to both the top cover sheet and the lower insulating member. A pressure relief member is provided on the top cover sheet. The lower insulating member has a second groove, which is located on the side of the lower insulating member facing the electrode assembly and communicates with the receiving cavity. The second groove has a second bottom wall along the direction of the lower insulating member towards the top cover sheet. The second bottom wall is spaced apart from the pressure relief member and is configured to burst open when the internal pressure of the secondary battery reaches a threshold, so that the internal pressure of the secondary battery directly acts on the pressure relief member.

[0009] In some embodiments, the lower insulating member has a first gap, the first gap is disposed on the second bottom wall, and the first gap penetrates the second bottom wall along the direction of the lower insulating member toward the top cover sheet.

[0010] In some embodiments, the orthographic projection of the pressure relief member onto the lower insulation member is at least partially located on the second bottom wall and at least partially located within the first gap.

[0011] In some embodiments, the lower insulating member has a plurality of the first gaps, the plurality of first gaps being spaced apart and surrounding the edge of the second bottom wall.

[0012] In some embodiments, the lower insulating member is further provided with a third groove, which is disposed on the side of the second bottom wall facing the electrode assembly and communicates with the second groove.

[0013] In some embodiments, the third groove is disposed around the edge of the second bottom wall.

[0014] In some embodiments, the lower insulating member has a first gap, the first gap is disposed on the second bottom wall, and the first gap penetrates the second bottom wall along the direction of the lower insulating member toward the top cover plate, and the third groove communicates with the first gap.

[0015] In some embodiments, the third groove has a third bottom wall, the first gap is disposed on the third bottom wall, the third bottom wall forms at least a portion of the second bottom wall, and the first gap penetrates the third bottom wall in the direction of the lower insulator toward the top cover sheet.

[0016] In some embodiments, the lower insulating member is provided with a plurality of the third grooves, and the lower insulating member is provided with a first gap, the first gap penetrating the second bottom wall, the first gap being disposed between two adjacent third grooves and communicating with the two third grooves respectively.

[0017] In some embodiments, the lower insulating member is provided with a plurality of the third grooves, and two adjacent third grooves intersect and communicate with each other.

[0018] In some embodiments, the length of the first gap is L2mm and the width of the first gap is W1mm; a connecting portion is provided between two adjacent first gaps, and the dimension of the connecting portion along the circumference of the second bottom wall is L1mm; satisfying:

[0019] 0.1≤L1≤5;

[0020] 0.5≤L2≤20;

[0021] 0.1≤W1≤5.

[0022] In some embodiments, along the direction of the lower insulating member toward the top cover sheet, the dimension of the third bottom wall is H3mm and the dimension of the second bottom wall is H4mm, satisfying: 0.02≤H3 / H4≤0.8; wherein, 0.1≤H3≤4, 0.5≤H4≤5.

[0023] In some embodiments, the lower insulating member has a first groove disposed on the side of the lower insulating member facing the top cover sheet, the first groove having a first bottom wall, and the orthographic projection of the pressure relief member on the lower insulating member being located within the first groove, such that the pressure relief member is spaced apart from the lower insulating member; a second groove is disposed on the side of the first bottom wall facing the electrode assembly, the second bottom wall forming at least a portion of the first bottom wall.

[0024] In some embodiments, along the direction of the lower insulating member toward the top cover plate, the depth of the second groove is H1 mm, the distance between the side of the first bottom wall facing the electrode assembly and the top cover plate is H2 mm, and the lower insulating member satisfies: 0.01≤H1 / H2≤0.8; wherein, 0.01≤H1≤12, and / or, 1≤H2≤15.

[0025] Accordingly, the battery pack described in this application includes a secondary battery as described in any of the foregoing embodiments.

[0026] Accordingly, an electrical device described in this application includes a secondary battery as described in any of the foregoing embodiments, or a battery pack as described in the foregoing embodiments.

[0027] Beneficial Effects: Compared with the prior art, a secondary battery according to an embodiment of this application includes a housing, an electrode assembly, and a top cover assembly. The housing has a receiving cavity, and the electrode assembly is disposed in the receiving cavity. The top cover assembly includes a top cover sheet and a lower insulating member. The top cover sheet is connected to the housing and seals the receiving cavity. The lower insulating member is disposed between the top cover sheet and the electrode assembly, and is connected to both the top cover sheet and the lower insulating member. A pressure relief member is disposed on the top cover sheet. The lower insulating member has a second groove, which is disposed on the side of the lower insulating member facing the electrode assembly and communicates with the receiving cavity. The second groove has a second bottom wall along the direction of the lower insulating member towards the top cover sheet. The second bottom wall is spaced apart from the pressure relief member. The second bottom wall is configured to burst open when the internal pressure of the secondary battery reaches a threshold, so that the internal pressure of the secondary battery directly acts on the pressure relief member. This application provides a second groove on the lower insulating member with an opening facing the electrode assembly. The second groove has a second bottom wall, which can burst open when the internal pressure of the secondary battery reaches a threshold due to thermal runaway. This allows the internal pressure to directly act on the pressure relief component, enabling the pressure relief component to open and release pressure. This replaces the prior art's method of providing a through hole on the lower insulating member to allow thermal runaway gas to pass through and open the pressure relief component, greatly reducing the area of ​​the exposed metal on the top cover, thereby significantly reducing the risk of internal short circuits in the secondary battery. The second bottom wall is spaced apart from the pressure relief component, providing space for the second bottom wall to burst open, thus facilitating the direct action of the internal pressure of the secondary battery on the pressure relief component. In addition, the second groove allows the second bottom wall to be spaced apart from the electrode assembly, which facilitates the accumulation of gas in the second groove and its action on the second bottom wall during battery thermal runaway, making it easier for the second bottom wall to burst open. At the same time, it also prevents the electrode assembly from contacting the second bottom wall under vibration conditions, which could cause the second bottom wall to crack, ensuring the safety of the secondary battery during normal operation.

[0028] Compared with the prior art, a battery pack according to an embodiment of this application includes a secondary battery as described in any of the foregoing embodiments. It is understood that this battery pack possesses all the technical features and effects of the aforementioned secondary batteries, which will not be repeated here.

[0029] Compared with the prior art, an electrical device according to an embodiment of this application includes a secondary battery as described in any of the foregoing embodiments, or a battery pack as described in the foregoing embodiments. It is understood that this electrical device possesses all the technical features and effects of the aforementioned secondary battery or battery pack, which will not be repeated here. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 is a schematic diagram of the overall structure of a secondary battery according to an embodiment of this application;

[0032] Figure 2 is a schematic diagram of the overall structure of a top cover assembly with multiple first gaps surrounding a second bottom wall according to an embodiment of this application;

[0033] Figure 3 is a top view of Figure 2;

[0034] Figure 4 is an enlarged view of part A in Figure 3;

[0035] Figure 5 is a sectional view of section AA in Figure 3;

[0036] Figure 6 is an enlarged view of part B in Figure 5;

[0037] Figure 7 is a schematic diagram of the overall structure of a top cover assembly in which a first gap is provided in the middle of the second bottom wall according to an embodiment of this application;

[0038] Figure 8 is a top view of Figure 7;

[0039] Figure 9 is a sectional view of section BB in Figure 8;

[0040] Figure 10 is an enlarged view of part C in Figure 8;

[0041] Figure 11 is a schematic diagram of the overall structure of a top cover assembly with a third groove provided on the second bottom wall according to an embodiment of this application;

[0042] Figure 12 is a top view of Figure 11;

[0043] Figure 13 is a sectional view of section CC in Figure 12;

[0044] Figure 14 is a schematic diagram of the overall structure of a top cover assembly that simultaneously provides a first gap and a third groove according to an embodiment of this application.

[0045] Figure 15 is a top view of Figure 14;

[0046] Figure 16 is a sectional view of section DD in Figure 15;

[0047] Figure 17 is a schematic diagram of the overall structure of a top cover assembly in an embodiment of this application, wherein third grooves are respectively provided at both ends of the first gap;

[0048] Figure 18 is a top view of Figure 17;

[0049] Figure 19 is a sectional view of section EE in Figure 18;

[0050] Figure 20 is a schematic diagram of the overall structure of a top cover assembly with third grooves respectively provided at both ends of the first gap according to another embodiment of this application;

[0051] Figure 21 is a top view of Figure 20;

[0052] Figure 22 is a sectional view of section FF in Figure 21;

[0053] Figure 23 is an enlarged view of part D in Figure 22;

[0054] Figure 24 is a schematic diagram of the overall structure of a top cover assembly of a mesh composed of multiple third grooves according to an embodiment of this application;

[0055] Figure 25 is a top view of Figure 24;

[0056] Figure 26 is a sectional view of section GG in Figure 25.

[0057] Explanation of reference numerals in the attached drawings: 1. Housing; 11. Receiving cavity; 2. Electrode assembly; 3. Top cover assembly; 31. Top cover plate; 311. Pressure relief component; 32. Lower insulating component; 321. First groove; 3211. First bottom wall; 322. Second groove; 3221. Second bottom wall; 323. First gap; 324. Third groove; 3241. Third bottom wall; 325. Connecting part; 326. Body; 3261. Exhaust port. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0059] In the description of this application, it should be understood that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, and "at least one" can mean one, two, or more, unless otherwise explicitly specified. In the description of this application, "perpendicular" means completely perpendicular to 90° or almost completely perpendicular, for example, the range of included angles from 80° to 100° is considered perpendicular. Similarly, "parallel" means completely parallel or almost completely parallel, for example, the range of completely parallel angles from 10° is considered parallel.

[0060] With the increasing prominence of environmental issues, a low-carbon economy has become the mainstream of future economic development. New energy sources will gradually replace traditional polluting energy sources, and power batteries, as a representative of new energy, are gradually gaining recognition from manufacturers and consumers. Secondary batteries, as the main power source for new energy vehicles, have become one of the key components of electric vehicles. As a critical component of secondary batteries, the top cover assembly has a significant impact on the energy density, economy, and safety of the secondary battery. The top cover assembly is equipped with a pressure relief device (explosion-proof valve) to promptly release internal pressure and prevent secondary battery explosion when abnormal gas production causes a rapid increase in internal pressure. Furthermore, to protect the pressure relief component (explosion-proof valve) from the influence of internal components of the secondary battery, the current mainstream design incorporates a boss feature in the area of ​​the lower insulating component (lower plastic) corresponding to the explosion-proof valve. This separates the explosion-proof valve from the electrode assembly, preventing mechanical damage to the explosion-proof valve caused by core vibrations during operation, or interference between the electrode and the explosion-proof valve, which could lead to internal short circuits. Simultaneously, to ensure the venting and pressure relief function of the explosion-proof valve is not affected, a venting through-hole feature is provided on the boss of the lower plastic component, allowing gas generated within the secondary battery to pass smoothly and act on the explosion-proof valve. However, foreign metal objects inside the secondary battery may come into contact with the pressure relief component through the through-hole feature, causing an internal short circuit and thus posing a risk of corrosion and cracking of the pressure relief component.

[0061] In view of this, embodiments of this application provide a secondary battery, which aims to solve the above-mentioned technical problems.

[0062] Referring to Figures 1, 2, 5, and 6, this application provides a secondary battery, including a housing 1, an electrode assembly 2, and a top cover assembly 3. The housing 1 has a receiving cavity 11, and the electrode assembly 2 is disposed in the receiving cavity 11. The top cover assembly 3 includes a top cover plate 31 and a lower insulating member 32. The top cover plate 31 is connected to the housing 1 and seals the receiving cavity 11. The lower insulating member 32 is disposed between the top cover plate 31 and the electrode assembly 2, and is connected to both the top cover plate 31 and the lower insulating member 32. A pressure relief member 3 is provided on the top cover plate 31. 11. The lower insulating member 32 has a second groove 322, which is disposed on the side of the lower insulating member 32 facing the electrode assembly 2 and communicates with the receiving cavity 11. The second groove 322 has a second bottom wall 3221 along the direction of the lower insulating member 32 toward the top cover plate 31. The second bottom wall 3221 is spaced apart from the pressure relief member 311. The second bottom wall 3221 is configured to burst open when the internal pressure of the secondary battery reaches a threshold, so that the internal pressure of the secondary battery directly acts on the pressure relief member 311.

[0063] In this embodiment, a second groove 322 with an opening facing the electrode assembly 2 is provided on the lower insulating member 32, and the second groove 322 has a second bottom wall 3221. The second bottom wall 3221 can burst open when the internal pressure of the secondary battery reaches a threshold due to thermal runaway, allowing the internal pressure to directly act on the pressure relief member 311, thereby opening and releasing pressure from the pressure relief member 311. This replaces the prior art of providing a through hole on the lower insulating member 32 to allow thermal runaway gas to pass through and open the pressure relief member 311, greatly reducing the area of ​​exposed metal on the top cover 31, thereby greatly reducing the risk of internal short circuit in the secondary battery; wherein, the second bottom wall 3221... The spaced arrangement of the second bottom wall 3221 and the pressure relief component 311 provides space for the second bottom wall 3221 to burst, thus facilitating the direct application of internal pressure of the secondary battery to the pressure relief component 311. In addition, the arrangement of the second groove 322 allows the second bottom wall 3221 and the electrode assembly 2 to be spaced apart. This facilitates the accumulation of gas in the second groove 322 and its application to the second bottom wall 3221 during battery thermal runaway, which is more conducive to the bursting of the second bottom wall 3221. At the same time, it can also prevent the electrode assembly 2 from contacting the second bottom wall 3221 under vibration conditions, which could lead to the rupture of the second bottom wall 3221 and ensure the safety of the secondary battery during normal operation.

[0064] Specifically, in this embodiment, the lower insulating member 32 can be a plastic part formed by injection molding or other processes, which can achieve a better insulation effect. The lower insulating member 32 is connected to the top cover plate 31, so that the lower insulating member 32 is fixed in position within the receiving cavity 11 of the housing 1. At the same time, the lower insulating member 32 is connected to the electrode assembly 2. Specifically, a part of the lower insulating member 32 abuts against the electrode assembly 2, so that the electrode assembly 2 is fixed in position within the receiving cavity 11, reducing the movement of the electrode assembly 2 within the housing 1 under vibration conditions, thereby effectively avoiding abnormalities such as breakage of the connection between the electrode tab and the electrode post.

[0065] It is understood that the second bottom wall 3221 of the second groove 322 in this embodiment is configured to burst open when the internal pressure of the secondary battery reaches a threshold, so that the internal pressure of the secondary battery directly acts on the pressure relief member 311. At this time, the corresponding second bottom wall 3221 is relatively thin compared with other areas of the lower insulating member 32, so that it can burst open when the internal pressure is large.

[0066] It should be noted that in this embodiment, the second groove 322 is disposed on the side of the lower insulating member 32 facing the electrode assembly 2. This can be understood as the opening of the second groove 322 facing the electrode assembly 2. The second bottom wall 3221 of the corresponding second groove 322 is disposed opposite to the groove opening of the second groove 322. The second bottom wall 3221 is spaced apart from the electrode assembly 2. Thus, when the secondary battery is under vibration, even if the electrode assembly 2 vibrates, it will only contact the groove opening of the second groove 322 and will not contact the second bottom wall 3221. This can effectively ensure the structural integrity of the second bottom wall 3221 when the secondary battery is operating normally, thereby effectively isolating metal foreign objects in the battery through the second bottom wall 3221, and thus effectively avoiding the occurrence of internal short circuits in the secondary battery.

[0067] It should also be noted that in this embodiment, along the direction from the lower insulating member 32 toward the top cover plate 31, the second bottom wall 3221 and the pressure relief member 311 are spaced apart. It can be understood that there is a gap space between the second bottom wall 3221 and the pressure relief member 311, which can provide a bursting space for the second bottom wall 3221, thereby facilitating the direct action of internal pressure on the pressure relief member 311 to achieve rapid pressure relief.

[0068] It should also be noted that, referring to Figure 9, in this embodiment of the application, the lower insulating member 32 may include a body 326, the body 326 having a vent 3261, and a second bottom wall 3221 connected to the wall of the vent 3261, such that the second bottom wall 3221 is spaced apart from the top cover plate 31 and the electrode assembly 2 along the direction of the lower insulating member 32 toward the top cover plate 31. The wall of the vent 3261 and the second bottom wall 3221 form a second groove 322, thus allowing the lower insulating member 32 to pass through the body of the lower insulating member 32. 326 and the second bottom wall 3221 effectively isolate the top cover plate 31 from the electrode assembly 2 and metal foreign objects; they also enable the second bottom wall 3221 to burst open toward the top cover plate 31 so that the internal pressure of the battery can directly act on the pressure relief component 311, facilitating the rapid opening and pressure relief of the pressure relief component 311; at the same time, they can prevent the second bottom wall 3221 from directly contacting the electrode assembly 2, ensuring the structural stability of the second bottom wall 3221 under vibration conditions, and avoiding the risk of increased internal short circuit due to damage to the second bottom wall 3221.

[0069] Please refer to Figures 2-10, 14, 15, 17, 18, and 20-22. In some embodiments, the lower insulating member 32 is provided with a first gap 323. The first gap 323 is disposed on the second bottom wall 3221 and penetrates the second bottom wall 3221 along the direction of the lower insulating member 32 toward the top cover plate 31.

[0070] In this embodiment, by setting the first gap 323, it is easier to break through the second bottom wall 3221 when there is abnormal gas generation or increased internal pressure inside the secondary battery, so as to realize the rapid bursting of the second bottom wall 3221, thereby facilitating the rapid opening and pressure relief of the pressure relief component 311 and improving the safety of the entire battery pack.

[0071] Specifically, in this embodiment, a first gap 323 is provided on the second bottom wall 3221. At this time, the thermal runaway gas in the battery preferentially passes through the first gap 323 and flows into the gap between the pressure relief member 311 and the second bottom wall 3221. Due to the excessively high internal pressure of the battery, the high-pressure thermal runaway gas can impact the second bottom wall 3221 on both sides of the first gap 323 against the top cover plate 31 and cause the second bottom wall 3221 to deform and burst against the top cover plate 31. In this way, the thermal runaway gas acts on the pressure relief member 311 more quickly, realizing the rapid opening of the pressure relief member 311.

[0072] It should be noted that the width of the first gap 323 in this embodiment is small, thereby reducing the metal exposure of the top cover 31 and blocking metal foreign objects. This makes it easier for the second bottom wall 3221 to burst open, while reducing the possibility of metal foreign objects passing through and causing a short circuit inside the secondary battery.

[0073] In some embodiments, the orthographic projection of the pressure relief member 311 onto the lower insulating member 32 is at least partially located on the second bottom wall 3221 and at least partially located within the first gap 323.

[0074] It is understood that in this embodiment, along the direction from the lower insulating member 32 toward the top cover plate 31, the pressure relief member 311 is disposed opposite to the second bottom wall 3221. Furthermore, the pressure relief member 311 is disposed opposite to the first gap 323. In this case, the high-pressure thermal runaway gas can directly act on the pressure relief member 311 after the second bottom wall 3221 bursts, realizing the rapid opening and pressure relief of the pressure relief member 311. In addition, with this structure, when the distance between the pressure relief member 311 and the second bottom wall 3221 is permissible, the bursting of the second bottom wall 3221 can directly act on the pressure relief member 311. The second bottom wall 3221 directly contacts the pressure relief member 311, causing an impact on the pressure relief member 311, thereby causing the weak area of ​​the pressure relief member 311 to break, and enabling the pressure relief member 311 to open and relieve pressure more quickly.

[0075] Referring to Figures 2-4, in some embodiments, the lower insulating member 32 is provided with a plurality of first gaps 323, which are arranged at intervals and surround the edge of the second bottom wall 3221.

[0076] In this embodiment, multiple first gaps 323 are arranged at intervals, which makes it easier for the second bottom wall 3221 to burst open more quickly when it is impacted by internal pressure, thereby making it easier for the pressure relief component 311 to open quickly to relieve pressure.

[0077] Specifically, it can be understood that multiple first gaps 323 are arranged at intervals. At this time, a connecting part 325 is provided between two adjacent first gaps 323 to separate the two adjacent first gaps 323. The connecting part 325 has a relatively small area and is more likely to break when subjected to high pressure impact inside the battery. This allows the internal pressure of the battery to act on the pressure relief component 311 more quickly, making it easier for the pressure relief component 311 to open and relieve pressure.

[0078] More specifically, the second bottom wall 3221 can be connected to the hole wall of the exhaust hole 3261 through the connecting part 325. At this time, the connecting part 325 between the second bottom wall 3221 and the hole wall of the exhaust hole 3261 is relatively small. When subjected to thermal runaway gas impact, the connecting part 325 can break quickly to realize the rapid bursting of the second bottom wall 3221, thereby facilitating the rapid opening and pressure relief of the pressure relief component 311.

[0079] Referring to Figures 11-25, in some embodiments, the lower insulating member 32 is further provided with a third groove 324, which is disposed on the side of the second bottom wall 3221 facing the electrode assembly 2 and communicates with the second groove 322.

[0080] In this embodiment, the third groove 324 is disposed on the second bottom wall 3221. At this time, the third groove 324 has a third bottom wall 3241, which is thinner than the second bottom wall 3221, and is equivalent to a weak area on the second bottom wall 3221. When the internal pressure increases due to thermal runaway inside the secondary battery, the internal pressure acts on the second bottom wall 3221, and the second bottom wall 3221 breaks from the third bottom wall 3241 of the third groove 324, realizing the rapid bursting of the second bottom wall 3221, thereby realizing the rapid opening and pressure relief of the pressure relief component 311.

[0081] It should be noted that, in this embodiment of the application, a weak area is formed on the second bottom wall 3221 by setting a third groove 324, which makes it easier for the second bottom wall 3221 to burst open. At this time, the second bottom wall 3221 completely seals the exhaust hole 3261, which can completely isolate the metal foreign object and prevent the metal foreign object from contacting the top cover plate 31 and causing a short circuit.

[0082] Please refer to Figures 11, 12, 14, 15, 17, 18, 20 and 21. In some embodiments, the third groove 324 is disposed around the edge of the second bottom wall 3221.

[0083] In this embodiment, the third groove 324 is disposed around the edge of the second bottom wall 3221, which allows the third groove 324 to have a larger distribution area, thus facilitating the bursting of the second bottom wall 3221.

[0084] Please refer to Figures 14, 15, 17, 18, 20 and 21. In some embodiments, the lower insulating member 32 is provided with a first gap 323. The first gap 323 is disposed on the second bottom wall 3221 and penetrates the second bottom wall 3221 along the direction of the lower insulating member 32 toward the top cover plate 31. The third groove 324 communicates with the first gap 323.

[0085] In this embodiment, by using the design of the third groove 324 and the first gap 323 to cooperate, the second bottom wall 3221 can be rapidly opened while the exposed metal area of ​​the top cover 31 is small, thereby enabling the pressure relief component 311 to be opened and relieve pressure quickly.

[0086] Specifically, in this embodiment, the first gap 323 provides an opening for the second bottom wall 3221 to burst open, and the third groove 324 provides a weak area for the second bottom wall 3221, making it easier for the second bottom wall 3221 to burst open. At the same time, the first gap 323 and the third groove 324 are connected. At this time, it is equivalent to the first gap 323 opening up the bottom wall of the third groove 324, thereby reducing the difficulty of the second bottom wall 3221 bursting open.

[0087] Referring to Figures 12, 15 and 18, in some embodiments, the third groove 324 has a third bottom wall 3241, which forms at least a portion of the second bottom wall 3221. A first gap 323 is disposed on the third bottom wall 3241 and extends through the third bottom wall 3241 along the direction of the lower insulating member 32 toward the top cover plate 31.

[0088] In this embodiment, the first gap 323 is directly set on the third bottom wall 3241 of the third groove 324. When the high-pressure gas opens the first gap 323, it directly acts on the third bottom wall 3241 and opens the third bottom wall 3241, realizing the rapid rupture of the third bottom wall 3241, which is more conducive to the bursting of the second bottom wall 3221. It is also more conducive to the rapid opening and pressure relief of the pressure relief component 311.

[0089] Please refer to Figures 11, 18, 20 and 21. In some embodiments, the lower insulating member 32 is provided with a plurality of third grooves 324 and a first gap 323. The first gap 323 penetrates the second bottom wall 3221 and is disposed between two adjacent third grooves 324 and communicates with the two third grooves 324 respectively.

[0090] In this embodiment, multiple third grooves 324 are provided to cooperate with the first gap 323, providing more breakthroughs for the second bottom wall 3221 to burst open, which can further realize the rapid bursting of the second bottom wall 3221.

[0091] Referring to Figures 24-26, in some embodiments, the lower insulating member 32 is provided with a plurality of third grooves 324, and two adjacent third grooves 324 intersect and are connected.

[0092] In this embodiment, multiple third grooves 324 intersect and connect with each other. This not only strengthens the connection between the top cover plate 31 and the electrode assembly 2, preventing metal foreign objects from short-circuiting with the top cover plate 31, but also provides multiple weak areas for the second bottom wall 3221. In the event of thermal runaway inside the battery, this provides more bursting areas for the second bottom wall 3221, thereby enabling the second bottom wall 3221 to burst open more quickly.

[0093] Referring to Figure 4, in some embodiments, the length of the first gap 323 is L2 mm, and the width of the first gap 323 is W1 mm; a connecting portion 325 is provided between two adjacent first gaps 323, and the dimension of the connecting portion 325 along the circumference of the second bottom wall 3221 is L1 mm; satisfying:

[0094] 0.1≤L1≤5;

[0095] 0.5≤L2≤20;

[0096] 0.1≤W1≤5.

[0097] In this embodiment of the application, by controlling the dimensions of the first gap and the connecting part 325 within the above-mentioned range, it is possible to ensure that the overall processing difficulty of the lower insulating part 32 is not too high, and at the same time, the qualification rate of the finished product of the lower insulating part 32 can be guaranteed. This avoids the problems of increased production difficulty and low structural strength of the connecting part 325 caused by the first gap 323 being too narrow or the connecting part 325 being too narrow or too long.

[0098] It should be noted that the numerical range of L1 can be any one or any two values ​​from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5. The numerical range of L2 can be any one or any two values ​​from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 20. The numerical range of W1 can be any one or any two values ​​from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5. If the size of the connecting part 325 is too small, it is prone to breakage, leading to internal shortness. If the size of the connecting part 325 is too large, its overall strength may be too high, making it difficult to break. This could result in the second bottom wall 3221 failing to burst open smoothly. Therefore, controlling the size of the first gap and the connecting part 325 within the aforementioned range ensures the smooth production of the lower insulating component 32, prevents the second bottom wall 3221 from having insufficient structural strength to block metal foreign objects, and ensures that the second bottom wall 3221 can burst open smoothly in the event of thermal runaway of the secondary battery. This allows the high internal pressure of the battery caused by the high-temperature gas generated during thermal runaway to directly act on the pressure relief component 311.

[0099] Please refer to Figure 23. In some embodiments, along the direction from the lower insulating member 32 toward the top cover plate 31, the dimension of the third bottom wall 3241 is H3 mm and the dimension of the second bottom wall 3221 is H4 mm, satisfying: 0.02≤H3 / H4≤0.8; where 0.1≤H3≤4 and 0.5≤H4≤5.

[0100] In this embodiment, by controlling the second bottom wall 3221 and the third bottom wall 3241 to satisfy: 0.02≤H3 / H4≤0.8; where 0.1≤H3≤4 and 0.5≤H4≤5, the third bottom wall 3241 can be made thinner than the second bottom wall 3221, which is more conducive to the rapid rupture of the third bottom wall 3241 during the thermal runaway of the secondary battery, thereby enabling the second bottom wall 3221 to burst open rapidly, and the higher internal pressure generated by the thermal runaway directly acts on the pressure relief component 311.

[0101] It should be noted that the numerical range of H3 / H4 can be any one value or any two values ​​from 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, and 0.8. Specifically, the numerical range of H3 can be any one value or any two values ​​from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, and 4. The value of H4 can be any one or any two values ​​from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, and 5. If the value is too small, the lower insulating part 32 will be difficult to process, the yield will be reduced, and the production process cost will be increased; if the value is too small, the third groove 324 and the corresponding third bottom wall 3241 will not be able to assist the second bottom wall 3221 in bursting open.

[0102] Referring to Figures 5, 6, 9, 13, 16, 19, 22, 23, and 26, in some embodiments, the lower insulating member 32 has a first groove 321, which is disposed on the side of the lower insulating member 32 facing the top cover plate 31. The first groove 321 has a first bottom wall 3211, and the orthographic projection of the pressure relief member 311 on the lower insulating member 32 is located within the first groove 321, so that the pressure relief member 311 and the lower insulating member 32 are spaced apart. A second groove 322 is disposed on the side of the first bottom wall 3211 facing the electrode assembly 2, and the second bottom wall 3221 forms at least a portion of the first bottom wall 3211. A first gap 323 may also be provided on the second bottom wall 3221, and the second groove 322 communicates with the first groove 321 through the first gap 323.

[0103] In this embodiment, the opening of the first groove 321 faces the top cover plate 31, and the first bottom wall 3211 of the first groove 321 is spaced apart from the top cover plate 31. Furthermore, the orthogonal projection of the pressure relief member 311 onto the lower insulating member 32 is located within the first groove 321, and the first bottom wall 3211 is spaced apart from the pressure relief member 311. The second groove 322 is located on the side of the first bottom wall 3211 facing the electrode assembly 2, and the second bottom wall 3221 forms at least a portion of the first bottom wall 3211. Therefore, the pressure relief member 311 and the second bottom wall 3221 are correspondingly spaced apart. Thus, the first groove 321 allows the second bottom wall 3221 to be spaced apart from the pressure relief member 311, providing space for the second bottom wall 3221 to burst open into the first groove 321 when the internal pressure of the battery reaches the bursting threshold. Simultaneously, the structure around the opening of the first groove 321 can be connected to the top cover plate 31, achieving structural stability of the top cover assembly 3.

[0104] Referring to Figure 6, in some embodiments, along the direction of the lower insulating member 32 toward the top cover plate 31, the depth of the second groove 322 is H1 mm, the distance between the side of the first bottom wall 3211 toward the electrode assembly 2 and the top cover plate 31 is H2 mm, and the lower insulating member 32 satisfies: 0.01≤H1 / H2≤0.8; wherein, 0.01≤H1≤12, and / or, 1≤H2≤15.

[0105] In this embodiment, by setting 0.01≤H1 / H2≤0.8, on the one hand, a suitable distance is ensured between the second bottom wall 3221 and the electrode assembly 2, preventing the second bottom wall 3221 from contacting the electrode assembly 2 under vibration conditions, thereby avoiding mechanical damage to the second bottom wall 3221 caused by direct impact from the electrode assembly 2. On the other hand, it is more conducive to the thermal runaway gas converging into the second groove 322 and acting on the second bottom wall 3221, realizing the rapid bursting of the second bottom wall 3221. At the same time, it can also prevent the second bottom wall 3221 from directly contacting the pressure relief component 311 under vibration conditions, thus avoiding mechanical damage to the pressure relief component 311 and preventing the entire battery from being destroyed.

[0106] It should be noted that the numerical range of H1 / H2 can be any one value or any two values ​​from 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, and 0.8. Specifically, the numerical range of H1 can be any one value or any two values ​​from 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.5, 1, 1.5, 2, 3, 4, 5, 8, 10, and 12. The numerical range of H2 can be any one of the following values ​​or a range between any two values: 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 12, 15.

[0107] It should be noted that if the ratio of H1 / H2 is too small, the second bottom wall 3221 is likely to come into contact with the electrode assembly 2 and be damaged by the electrode assembly 2 under vibration conditions, resulting in an excessive exposed metal area of ​​the top cover 31, which may easily cause an internal short circuit in the battery. If the ratio of H1 / H2 is too large, under vibration conditions, although the second bottom wall 3221 is not likely to come into contact with the electrode assembly 2, the second bottom wall 3221 is likely to come into direct contact with the pressure relief component 311, causing mechanical damage to the pressure relief component 311, thereby leading to battery failure.

[0108] It should also be noted that, in the above embodiments, any one of the dimensions H1, H2, H3, H4, L1, L2, and W1 can be measured using some commonly used dimensional measurement methods. For example, measuring tools such as rulers, micrometers, and vernier calipers can be used to measure the corresponding dimensions. Alternatively, a projection method can be used to measure the dimensions by using a projection measuring device (such as a digital microscope or image measuring instrument) to obtain an image of the first gap and the connecting part.

[0109] The secondary battery of this application will be described in detail below with reference to specific embodiments.

[0110] Table 1

[0111] Table 2

[0112] Table 3

[0113] Referring to Tables 1, 2, and 3, as can be seen from the above embodiments and comparative examples, when H1 and H2 satisfy: 0.01≤H1 / H2≤0.8, where 0.01≤H1≤12, and / or 1≤H2≤15, under vibration conditions, the second bottom wall 3221 will neither contact the electrode assembly 2 nor the pressure relief component 311. In this case, during normal operation of the secondary battery, it can be ensured that neither the second bottom wall 3221 nor the pressure relief component 311 will suffer mechanical damage. When H1 and / or H2 are outside the above ranges, under vibration conditions, the second bottom wall 3221 will either contact the electrode assembly 2 or the pressure relief component 311, which will significantly affect the safety of the secondary battery, causing it to malfunction. When H3 and H4 satisfy: 0.02≤H3 / H4≤0.8, where 0.1≤H3≤4 and 0.5≤H4≤5, the third bottom wall 3241 can be successfully destroyed and burst open, thereby allowing the second bottom wall 3221 to burst open smoothly, enabling the secondary battery to release pressure smoothly when the internal pressure reaches the threshold. If the value is too small, the lower insulating part 32 becomes more difficult to process, and may even be impossible to process. If the value is too large, the third bottom wall 3241 will be difficult to burst open, affecting the smooth pressure release during thermal runaway of the secondary battery. When 0.1≤L1≤5, 0.5≤L2≤20, and 0.1≤W1≤5, the lower insulating part 32 can be successfully processed with low process difficulty, and the connecting part 325 can be destroyed when the internal pressure of the battery reaches the threshold. If the value is too small, the lower insulating part 32 will be difficult to process and have a low forming rate. If the value is too large, the connection part 325 will have excessive strength, and when the internal pressure of the battery reaches the threshold, the second bottom wall 3221 will not be able to burst open smoothly, resulting in obstruction of the venting and pressure relief of the pressure relief part 311. Therefore, when the secondary battery of this application embodiment meets the conditions in the table above, the safety and reliability of the secondary battery can be significantly improved.

[0114] Accordingly, the battery pack described in this application includes the secondary battery as described in any of the foregoing embodiments. It is understood that the battery pack in this application includes all the technical features and effects of the aforementioned secondary battery, which will not be repeated here.

[0115] Accordingly, the electrical device described in this application includes a secondary battery as described in any of the foregoing embodiments, or a battery pack as described in the foregoing embodiments. It is understood that the electrical device in this application includes all the technical features and effects of the aforementioned secondary battery or battery pack, and will not be repeated here.

[0116] Of course, the electrical devices referred to in this application can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be new energy vehicles, including pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles; spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. This application does not impose any special limitations on the above-mentioned electrical devices.

[0117] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0118] The foregoing has provided a detailed description of a secondary battery, battery pack, and power-consuming device provided in the embodiments of this application, and specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A secondary battery, wherein, include: The shell (1) has a receiving cavity (11); Electrode assembly (2) is disposed in the receiving cavity (11); A top cover assembly (3) includes a top cover plate (31) and a lower insulating member (32). The top cover plate (31) is connected to the housing (1) and covers the receiving cavity (11). The lower insulating member (32) is disposed between the top cover plate (31) and the electrode assembly (2), and is connected to both the top cover plate (31) and the electrode assembly (2). A pressure relief member (311) is provided on the top cover plate (31), and the lower insulating member (32) has a second groove (322). The second groove (322) is disposed on the lower insulating member. 32) On the side facing the electrode assembly (2), the second groove (322) communicates with the receiving cavity (11); the second groove (322) has a second bottom wall (3221) along the direction of the lower insulator (32) toward the top cover plate (31), the second bottom wall (3221) is spaced apart from the pressure relief member (311), and the second bottom wall (3221) is configured to burst open when the internal pressure of the secondary battery reaches a threshold, so that the internal pressure of the secondary battery acts directly on the pressure relief member (311).

2. The secondary battery according to claim 1, wherein The lower insulating member (32) is provided with a first gap (323), the first gap (323) is disposed on the second bottom wall (3221), and the first gap (323) penetrates the second bottom wall (3221) along the direction of the lower insulating member (32) toward the top cover plate (31).

3. The secondary battery according to claim 2, wherein The orthographic projection of the pressure relief element (311) onto the lower insulating element (32) is at least partially located on the second bottom wall (3221) and at least partially located within the first gap (323).

4. The secondary battery according to claim 3, wherein The lower insulating member (32) is provided with a plurality of first gaps (323), the plurality of first gaps (323) are arranged at intervals and surround the edge of the second bottom wall (3221).

5. The secondary battery according to claim 1, wherein The lower insulating member (32) is also provided with a third groove (324), which is located on the side of the second bottom wall (3221) facing the electrode assembly (2) and communicates with the second groove (322).

6. The secondary battery according to claim 5, wherein The third groove (324) is disposed around the edge of the second bottom wall (3221).

7. The secondary battery according to claim 6, wherein The lower insulating member (32) is provided with a first gap (323), the first gap (323) is disposed on the second bottom wall (3221), and the first gap (323) penetrates the second bottom wall (3221) along the direction of the lower insulating member (32) toward the top cover plate (31), and the third groove (324) communicates with the first gap (323).

8. The secondary battery according to claim 7, wherein The third groove (324) has a third bottom wall (3241) that forms at least a portion of the second bottom wall (3221), the first gap (323) is disposed on the third bottom wall (3241), and the first gap (323) penetrates the third bottom wall (3241) along the direction of the lower insulating member (32) toward the top cover plate (31).

9. The secondary battery according to claim 5, wherein The lower insulating member (32) is provided with a plurality of the third grooves (324), and the lower insulating member (32) is provided with a first gap (323). The first gap (323) penetrates the second bottom wall (3221). The first gap (323) is disposed between two adjacent third grooves (324) and communicates with the two third grooves (324) respectively.

10. The secondary battery according to claim 5, wherein The lower insulating member (32) is provided with a plurality of the third grooves (324), and two adjacent third grooves (324) intersect and are connected.

11. The secondary battery according to claim 4, wherein The length of the first gap (323) is L2 mm, and the width of the first gap (323) is W1 mm; a connecting part (325) is provided between two adjacent first gaps (323), and the dimension of the connecting part (325) along the circumference of the second bottom wall (3221) is L1 mm; satisfying: 0.1≤L1≤5； 0.5≤L2≤20； 0.1≤W1≤5。 12. The secondary battery according to claim 8, wherein Along the direction of the lower insulating member (32) toward the top cover plate (31), the size of the third bottom wall (3241) is H3 mm, and the size of the second bottom wall (3221) is H4 mm, satisfying: 0.02≤H3 / H4≤0.8; where 0.1≤H3≤4, 0.5≤H4≤5.

13. The secondary battery according to claim 1, wherein The lower insulating member (32) has a first groove (321) disposed on the side of the lower insulating member (32) facing the top cover plate (31). The first groove (321) has a first bottom wall (3211). The orthographic projection of the pressure relief member (311) on the lower insulating member (32) is located in the first groove (321) so that the pressure relief member (311) and the lower insulating member (32) are spaced apart. The second groove (322) is disposed on the side of the first bottom wall (3211) facing the electrode assembly (2). The second bottom wall (3221) forms at least a portion of the first bottom wall (3211).

14. The secondary battery according to claim 13, wherein Along the direction of the lower insulating member (32) toward the top cover plate (31), the depth of the second groove (322) is H1 mm, the distance between the side of the first bottom wall (3211) facing the electrode assembly (2) and the top cover plate (31) is H2 mm, and the lower insulating member (32) satisfies: 0.01≤H1 / H2≤0.8; wherein, 0.01≤H1≤12, and / or, 1≤H2≤15.

15. The secondary battery according to claim 11, wherein The lower insulating member (32) includes a body (326) having an exhaust hole (3261), a second bottom wall (3221) connected to the hole wall of the exhaust hole (3261), and the second bottom wall (3221) is spaced apart from the top cover plate (31) and the electrode assembly (2) along the direction of the lower insulating member (32) toward the top cover plate (31), and the hole wall of the exhaust hole (3261) and the second bottom wall (3221) form the second groove (322).

16. The secondary battery according to claim 15, wherein The second bottom wall (3221) is connected to the wall of the vent (3261) via the connecting part (325).

17. The secondary battery according to claim 1, wherein The lower insulating member (32) is formed by injection molding. The lower insulating member (32) is connected to the top cover plate (31) to fix the position of the lower insulating member (32) in the receiving cavity (11). A part of the lower insulating member (32) abuts against the electrode assembly (2).

18. The secondary battery according to claim 1, wherein The opening of the second groove (322) faces the electrode assembly (2), the second bottom wall (3221) of the second groove (322) is disposed opposite to the groove opening of the second groove (322), and the second bottom wall (3221) is spaced apart from the electrode assembly (2).

19. A battery pack, wherein, Includes the secondary battery as described in any one of claims 1-18.

20. An electrical device, comprising: This includes the secondary battery as described in any one of claims 1-18, or the battery pack as described in claim 19.

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