Secondary battery, battery pack, and electric apparatus

Abstract

The present application discloses a secondary battery, a battery pack, and an electric apparatus. The secondary battery has a first direction and a second direction that intersect. The secondary battery comprises a casing, an electrode assembly, and a top cover assembly. The casing has an accommodating cavity, and the electrode assembly is disposed within the accommodating cavity. The top cover assembly comprises a top cover plate and a lower insulating member. The top cover plate is connected to the casing and seals the accommodating cavity, and the lower insulating member is located within the accommodating cavity and is connected to the top cover plate. The top cover plate is provided with a pressure relief member, the lower insulating member is provided with a recess, and an orthographic projection of the pressure relief member on the lower insulating member in the first direction is located within the recess. The lower insulating member has a side wall enclosing the recess, the side wall is provided with an exhaust channel, and the exhaust channel extends through the side wall in the second direction. In the second direction, there is a gap between the side wall and the casing, and the exhaust channel communicates with the gap and the recess, respectively. A size of the gap in the second direction is e mm, and a size of the exhaust channel in the first direction is a mm, wherein e and a satisfy: 1 ≤ e / a ≤ 4.

Description

Secondary batteries, battery packs and electrical devices

[0001] This application claims priority to Chinese Patent Application No. 202411714976.5, filed on November 27, 2024, entitled "Secondary Battery, Battery Pack and Power Consumption 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 secondary battery is equipped with an explosion-proof valve on its top cover. In the event of thermal runaway within the battery, the valve opens promptly to release internal pressure and prevent explosion. To ensure the battery's insulation performance, an insulating component is installed between the electrode assembly core and the top cover plate. However, during use, the insulating component may experience obstructed venting, affecting the pressure relief function of the explosion-proof valve. Summary of the Invention

[0004] This application provides a secondary battery to solve the problem of poor venting of insulation components affecting the pressure relief of explosion-proof valves in existing secondary batteries. Another objective of this application is to provide a battery pack, and yet another objective is to provide an electrical device.

[0005] In a first aspect of this application, a secondary battery is provided, having intersecting first and second directions. The secondary battery includes a housing, an electrode assembly, and a top cover assembly. The housing has a receiving cavity. 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 covers the receiving cavity. The lower insulating member is located within the receiving cavity and connected to the top cover sheet. The top cover sheet has a pressure relief member, and the lower insulating member has a bottom wall and a side wall. The bottom wall is spaced apart from the pressure relief member along the first direction, and the side wall is connected to the periphery of the bottom wall to form a groove. The orthographic projection of the pressure relief member onto the lower insulating member along the first direction is located within the groove. An exhaust channel is provided on the side wall, penetrating the side wall along the second direction. Along the second direction, there is a gap between the side wall and the housing, and the exhaust channel communicates with both the gap and the groove. The gap along the second direction has a dimension of e mm, and the exhaust channel along the first direction has a dimension of a mm, where e and a satisfy: 1 ​​≤ e / a ≤ 4.

[0006] In some embodiments, along the first direction, the dimension of the sidewall is b mm, where b and a satisfy: 0.5 ≤ (ba) ≤ 10.

[0007] In some embodiments, 0.5 ≤ a ≤ 5, and / or 1 ≤ b ≤ 15.

[0008] In some embodiments, 1≤a≤3, and / or, 2≤b≤11.

[0009] In some embodiments, the secondary battery has a third direction intersecting the first direction and the second direction respectively, and the size of the exhaust channel along the third direction is c mm, where c satisfies: 0.5≤c≤10.

[0010] In some embodiments, 0.5 ≤ e ≤ 10.

[0011] In some embodiments, along the second direction, the minimum dimension between the sidewall and the pressure relief member is f mm, and the minimum distance between the pressure relief member and the housing is d mm, where f and d satisfy: 1≤(df)≤5.

[0012] In some embodiments, 1≤f≤45, and / or, 2≤d≤50.

[0013] In some embodiments, the sidewall is provided with a plurality of exhaust channels, the total opening area of ​​the plurality of exhaust channels being S1 mm. 2 The area of ​​the sidewall facing the housing along the second direction after removing the plurality of exhaust channels is S2 mm. 2 S1 and S2 satisfy: 0.5≤S1 / S2≤5.

[0014] In some embodiments, 50 ≤ S1 ≤ 2000, and / or 50 ≤ S2 ≤ 800.

[0015] In some embodiments, the lower insulating member has a plurality of through holes, which penetrate the bottom wall along the first direction and communicate with the groove, and the total area of ​​the plurality of through holes is S3 mm. 2 The area of ​​the pressure relief component facing the bottom wall is S4 mm. 2 S3 and S4 satisfy: 1≤S3 / S4≤3.

[0016] In some embodiments, 50 ≤ S3 ≤ 6000, and / or 50 ≤ S4 ≤ 2000.

[0017] In some embodiments, 50 ≤ S3 ≤ 3000, and / or 50 ≤ S4 ≤ 1500.

[0018] In a second aspect of this application, a battery pack is provided, including a secondary battery provided according to the first aspect of this application.

[0019] In a third aspect of this application, an electrical device is provided, comprising a secondary battery provided according to the first aspect of this application, or a battery pack provided according to the second aspect of this application.

[0020] A secondary battery according to an embodiment of this application has intersecting first and second directions. The secondary battery includes a casing, an electrode assembly, and a top cover assembly. The casing has a receiving cavity, in which the electrode assembly is disposed. The top cover assembly includes a top cover sheet and a lower insulating member. The top cover sheet is connected to the casing and seals the receiving cavity, and the lower insulating member is located within the receiving cavity and connected to the top cover sheet. The top cover sheet is provided with a pressure relief member. The lower insulating member has a bottom wall and a side wall. The bottom wall is spaced apart from the pressure relief member along the first direction, and the side wall is connected to the periphery of the bottom wall to form a groove. The orthographic projection of the pressure relief member along the first direction onto the lower insulating member is located within the groove. An exhaust channel is provided on the side wall, penetrating the side wall along the second direction. Along the second direction, there is a gap between the side wall and the casing, and the exhaust channel communicates with the gap and the groove respectively. The dimension of the gap along the second direction is e mm, and the dimension of the exhaust channel along the first direction is a mm, where e and a satisfy: 1≤e / a≤4.

[0021] In the embodiments of this application, an exhaust channel is provided on the sidewall of the lower insulating member, facing the housing, and communicating with the receiving cavity through the gap between the sidewall and the housing. Thus, when the secondary battery vents abnormally, the exhaust channel is less likely to be blocked by the electrode assembly, and the exhaust channel provides a flow path for the thermal runaway gas, allowing it to smoothly reach the pressure relief component and open for pressure relief. When the size e of the gap and the size a of the exhaust channel satisfy the range of 1 ≤ e / a ≤ 4, the sizes of the gap and the exhaust channel are within a reasonable range, ensuring that a large amount of thermal runaway gas can quickly be discharged from the exhaust channel into the groove and act on the pressure relief component, causing it to open and quickly relieve pressure. Furthermore, within this range, the secondary battery can also maintain a good cycle life.

[0022] The battery pack provided in this application includes the secondary battery as provided 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.

[0023] An electrical device according to an embodiment of this application includes a secondary battery as provided in any of the foregoing embodiments, or a battery pack as provided in any of the foregoing embodiments. It is understood that the electrical device according to an embodiment of this application includes all the technical features and effects of the aforementioned secondary battery, which will not be repeated here. Attached Figure Description

[0024] 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.

[0025] Figure 1 is a schematic diagram of the overall structure of a secondary battery according to some embodiments of this application;

[0026] Figure 2 is an exploded view of a secondary battery according to some embodiments of this application;

[0027] Figure 3 is a side view of a secondary battery along a second direction according to some embodiments of this application;

[0028] Figure 4 is a side view of the top cover assembly along a second direction according to some embodiments of this application;

[0029] Figure 5 is a cross-sectional view of section AA in Figure 3;

[0030] Figure 6 is a structural schematic diagram of the lower insulating member according to some embodiments of this application;

[0031] Figure 7 is a side view of the lower insulating member along the second direction according to some embodiments of this application;

[0032] Figure 8 is a bottom view of the lower insulating member along a first direction according to some embodiments of the present application, wherein the through hole is circular;

[0033] Figure 9 is a bottom view of the lower insulating member along a first direction according to some embodiments of this application, wherein the through hole is square;

[0034] Figure 10 is a bottom view of the lower insulating member along a first direction according to some embodiments of the present application, wherein the through hole is diamond-shaped;

[0035] Figure 11 is a partial cross-sectional view of a secondary battery according to some embodiments of this application, wherein the exhaust channel does not penetrate the sidewall along the first direction toward the top cover plate, and the direction of thermal runaway gas flow is indicated by arrows; and

[0036] Figure 12 is a partial cross-sectional view of a secondary battery according to some embodiments of the present application, wherein the exhaust channel extends through the sidewall toward the top cover plate in a first direction, and the direction of thermal runaway gas flow is indicated by arrows.

[0037] 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. Groove; 3211. Side wall; 3212. Bottom wall; 322. Exhaust channel; 323. Through hole; 4. Gap; Z, First direction; Y, Second direction; X, Third direction. Detailed Implementation

[0038] 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.

[0039] 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", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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 of this application.

[0040] 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 technical features indicated. Therefore, features defined as "first" or "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" is not limited to being perfectly perpendicular at 90°; for example, an angle between 80° and 100° is considered perpendicular. Similarly, "parallel" is not limited to being perfectly parallel; for example, a perfect parallel angle within a 10° range is considered parallel.

[0041] It should also be noted that in the accompanying drawings of this application, an arrow labeled Z indicates the first direction Z, an arrow labeled Y indicates the second direction Y, and an arrow labeled X indicates the third direction X. The introduction of the first direction Z, the second direction Y, and the third direction X is to facilitate the description of the structural positional relationships of the secondary battery, thereby aiding in understanding its structure. In the embodiments of this application, the first direction Z is the height direction of the secondary battery, the second direction Y is the width direction of the secondary battery, and the third direction X is the length direction of the secondary battery. Furthermore, the first direction Z, the second direction Y, and the third direction X intersect each other. Moreover, the first direction Z, the second direction Y, and the third direction X are perpendicular to each other.

[0042] 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 being used more and more. As the main power source for new energy vehicles, power batteries have become one of the key components of electric vehicles. Power batteries typically consist of multiple secondary batteries, among which 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 an explosion-proof valve. When abnormal gas production inside the secondary battery causes a rapid increase in internal pressure, the explosion-proof valve can open in time to release the internal pressure and prevent the secondary battery from exploding. At the same time, to ensure the insulation performance of the secondary battery, a lower insulating component is installed between the top cover and the electrode assembly to ensure the insulation performance at the top cover. However, the lower insulating component has the problem of hindering the transmission of abnormal gas production from the secondary battery to the explosion-proof valve, which may cause the explosion-proof valve to fail to release pressure in time, posing a risk of explosion to the secondary battery.

[0043] In view of this, embodiments of this application provide a secondary battery aimed at solving at least one of the above-mentioned problems.

[0044] Referring to Figures 1-7, this application provides a secondary battery with intersecting first direction Z and second direction Y. The secondary battery includes 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 covers the receiving cavity 11. The lower insulating member 32 is located in the receiving cavity 11 and is connected to the top cover plate 31. The top cover plate 31 is provided with a pressure relief member 311. The lower insulating member 32 has a bottom wall 3212 and a side wall 3211. The bottom wall 3212 is spaced apart from the pressure relief member 311 along the first direction Z. The side wall 3211 is connected to the periphery of the bottom wall 3212 to form a groove 321. The orthographic projection of the pressure relief member 311 along the first direction Z on the lower insulating member 32 is located in the groove 321. An exhaust channel 322 is provided on the side wall 3211, and the exhaust channel 322 penetrates the side wall 3211 along the second direction Y. Along the second direction Y, there is a gap 4 between the side wall 3211 and the housing 1, and the exhaust channel 322 communicates with both the gap 4 and the groove 321. The dimension of the gap 4 along the second direction Y is e mm, and the dimension of the exhaust channel 322 along the first direction Z is a mm, where e and a satisfy: 1≤e / a≤4.

[0045] In the secondary battery provided in this embodiment, an exhaust channel 322 is provided on the side wall 3211 of the lower insulating member 32. The exhaust channel 322 faces the housing 1 and communicates with the receiving cavity 11 through the gap 4 between the side wall 3211 and the housing 1. Thus, when the secondary battery vents abnormally, the exhaust channel 322 is less likely to be blocked by the electrode assembly 2, and the exhaust channel 322 effectively provides a flow path for thermal runaway gas, allowing the thermal runaway gas to smoothly reach the pressure relief member 311 and open the pressure relief member 311 for smooth pressure relief. Furthermore, within the aforementioned size range, a good cycle life of the secondary battery can be guaranteed.

[0046] Referring to Figures 6 and 7, the groove 321 of the lower insulator 32 is shown. The groove 321 provides a gas-carrying space and prevents the lower insulator 32 from compressing the pressure relief member 311. It also facilitates the direct action of thermal runaway gas on the pressure relief member 311 within the groove 321, allowing the pressure relief member 311 to open and release pressure. Referring to Figure 5, when the electrode assembly 2 abnormally generates gas (i.e., generates thermal runaway gas), the exhaust channel 322 provided on the side wall 3211 provides a path for the thermal runaway gas to flow into the groove 321. The opening of the groove 321 faces the pressure relief member 311, and the exhaust channel 322 on the side wall 3211 will not be blocked by the electrode assembly 2. The exhaust channel 322 faces the housing 1 of the secondary battery, and there is a gap 4 between the side wall 3211 and the housing 1, through which the exhaust channel 322 communicates. Since the lower insulator 32 is located within the receiving cavity 11, this gap 4 communicates with the receiving cavity 11. Electrode assembly 2 is disposed within the receiving cavity 11, therefore, thermal runaway gas generated by abnormal gas production in electrode assembly 2 will also accumulate within the receiving cavity 11. When the internal pressure of the secondary battery continuously increases due to thermal runaway gas, the thermal runaway gas will enter the groove 321 from within the receiving cavity 11 through the gap 4 and the exhaust channel 322, and directly act on the pressure relief component 311. When the pressure on the pressure relief component 311 reaches a certain value, the pressure relief component 311 will open and promptly discharge the thermal runaway gas to relieve pressure and prevent the secondary battery from exploding.

[0047] In some embodiments, the exhaust channel 322 not only penetrates the sidewall 3211 along the second direction Y, but also penetrates the sidewall 3211 towards the top cover plate 31 along the first direction Z, forming a U-shaped exhaust groove on the sidewall 3211. This reduces the manufacturing difficulty and facilitates the molding of the lower insulating component 32, while also minimizing obstruction of the thermal runaway gas flow path, allowing the thermal runaway gas to reach the groove 321 more quickly and act on the pressure relief component 311 to open and release pressure. Specifically, the thermal runaway gas generated by the abnormal gas production of the electrode assembly 2 flows from the receiving cavity 11 to the gap 4. After reaching the top cover plate 31, the airflow is blocked by the top cover plate 31 and the housing 1 and redirected, flowing into the exhaust channel 322. Since the exhaust channel 322 penetrates the sidewall 3211 towards the top cover plate 31, the airflow, which is redirected by the top cover plate 31 and the housing 1, loses some obstruction from the sidewall 3211 and directly enters the exhaust channel 322. As a result, the thermal runaway gas reaches the groove 321 more quickly and puts pressure on the pressure relief component 311, forcing the pressure relief component 311 to open and release pressure, thereby further increasing the pressure relief rate and reducing the possibility of secondary battery explosion.

[0048] Referring to Figure 11, when the exhaust channel 322 only penetrates the side wall 3211 along the second direction Y but not along the first direction Z towards the top cover plate 31, a portion of the thermal runaway gas will impact the top cover plate 31 along the first direction Z and be blocked by the top cover plate 31. Blocked by the top cover plate 31 and the housing 1, this portion of the thermal runaway gas is redirected and flows along the side wall 3211, entering the groove 321 through the exhaust channel 322 to act on the pressure relief member 311 and open it for pressure relief.

[0049] Referring to Figures 4, 6, 7, and 12, when the exhaust channel 322 is a U-shaped exhaust groove, a portion of the thermal runaway gas will impact the top cover plate 31 along the first direction Z and be blocked by the top cover plate 31. Blocked by the top cover plate 31 and the housing 1, this portion of the thermal runaway gas is redirected and can pass through the exhaust channel 322 into the groove 321 without being blocked by the side wall 3211, thus acting on the pressure relief component 311 and causing it to open for pressure relief. This allows for faster pressure relief, increases the pressure relief rate, and further reduces the possibility of secondary battery explosion.

[0050] In some embodiments of this application, the dimension a mm along the first direction Z of the exhaust channel 322 is used to limit the opening width of the exhaust channel 322 in the first direction Z, and the dimension e mm along the second direction Y of the gap 4 is used to limit the width of the gap 4 in the second direction Y. It should be noted that the pressure relief component 311 will only open for normal pressure relief when the gas pressure inside the secondary battery reaches a preset opening pressure value. Directly setting the exhaust channel 322 and the gap 4 to be connected allows thermal runaway gas to reach the groove 321 through the gap 4 and the exhaust channel 322 and act on the pressure relief component 311. If the opening width of the exhaust channel 322 is too small or the width of the gap 4 is too narrow, the thermal runaway gas may not be able to reach the pressure relief component 311 quickly for pressure relief, and may still cause the secondary battery to explode.

[0051] It should be noted that when the secondary battery is used in reverse, the lower insulating member 32 supports the electrode assembly 2, and the bottom wall 3212 is used to abut against the electrode assembly 2. With the exhaust channel 322 dimension unchanged, if the gap 4 is larger, the corresponding e / a value is also larger, and the supporting area of ​​the bottom wall 3212 on the electrode assembly 2 is smaller, which will affect the battery's cycle life. Therefore, in this embodiment, e and a satisfy 1≤e / a≤4. The value range of e / a can be any one or any two values ​​from 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 3.6, 3.7, 3.8, 3.9, and 4. When the dimensions a of the exhaust channel 322 and e of the gap 4 satisfy the range of 1 ≤ e / a ≤ 4, the dimensions of the gap 4 and the exhaust channel 322 are within a reasonable range. This ensures that a large amount of thermal runaway gas can be quickly discharged from the exhaust channel 322 into the groove 321 and act on the pressure relief component 311, causing the pressure relief component 311 to open and quickly relieve pressure. When e / a < 1, the width of the gap 4 along the second direction Y is smaller than the width of the exhaust channel 322 along the first direction Z. The bottleneck of airflow is at the gap 4, resulting in a problem where the airflow inflow rate is too slow to achieve the pressure relief effect. When e / a > 4, the dimension of the lower insulating component 32 in the second direction Y is too small. When the secondary battery is used upside down, there is a risk that the support area of ​​the lower insulating component 32 for the electrode assembly 2 is insufficient, which will affect the cycle life of the secondary battery.

[0052] In some embodiments, the dimension a mm of the exhaust channel 322 along the first direction Z further satisfies: 0.5 ≤ a ≤ 5. The dimension e mm of the gap 4 along the second direction Y further satisfies: 0.5 ≤ e ≤ 10. Wherein, the value of a can be any one or any two values ​​from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5. The value of e can be any one or any two values ​​from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10.

[0053] As shown in Figure 4, in some embodiments, the dimension of the sidewall 3211 along the first direction Z is b mm, where b satisfies: 0.5≤(ba)≤10.

[0054] It is understood that the dimension b of the side wall 3211 can be the dimension of the portion of the side wall 3211 without the exhaust passage 322 in the first direction Z, or the dimension of the side wall 3211 in the first direction Z before the exhaust passage 322 is opened.

[0055] It is understood that in the embodiments of this application, (ba) can be any one or any two values ​​from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10. When 0.5≤(ba)≤10, with a reasonable gap 4 between the sidewall 3211 and the shell 1, it can be ensured that the thermal runaway gas can enter the groove 321 from the exhaust channel 322 and quickly open the pressure relief component 311. When (ba)<0.5, not only is it difficult to manufacture the lower plastic part, but the wall thickness of the lower plastic part is too small, and the lower plastic part is easily damaged under vehicle vibration. Moreover, the overall support strength of the sidewall 3211 and even the lower insulation component 32 is low, and the lower insulation component 32 is prone to deformation, affecting the safety of the secondary battery when used in reverse. When (ba) > 10, the exhaust effect of the exhaust channel 322 may be affected, and there is a risk that the pressure cannot be released smoothly. In order to ensure the exhaust effect of the exhaust channel 322, the corresponding side wall 3211 has a larger dimension along the first direction Z, which will occupy too much space inside the secondary battery, resulting in a reduction in the volume of the electrode assembly 2, and thus a reduction in the capacity of the secondary battery.

[0056] In some embodiments, there may be one or more exhaust channels 322. When there are multiple exhaust channels 322, the difference between the dimension of the sidewall 3211 along the first direction Z and the dimension of each exhaust channel 322 along the first direction Z can be small or large. If multiple exhaust channels 322 are arranged at intervals along the third direction X, each exhaust channel 322 can occupy a larger dimension range of the sidewall 3211 in the first direction Z, thus achieving the effect of a larger exhaust channel 322, which facilitates the discharge of thermal runaway gas. If there is only one exhaust channel 322, the difference between the dimension of the exhaust channel 322 and the dimension of the sidewall 3211 in the first direction Z can be smaller to ensure a better exhaust effect. If there are multiple exhaust channels 322 arranged at intervals along the first direction Z, the difference between the dimension of each exhaust channel 322 and the dimension of the sidewall 3211 in the first direction Z can be larger, and the multiple exhaust channels 322 can cooperate to achieve a better exhaust effect.

[0057] In some embodiments, the dimension a mm of the venting channel 322 along the first direction Z of the lower insulating member 32 further satisfies 0.5 ≤ a ≤ 5. The value of a can be any one or a range between any two of the following: 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5. If the dimension a of the venting channel 322 along the first direction Z is too large, it may cause excessive processing difficulty for the lower insulating member 32, and even lead to a decrease in the support strength of the lower insulating member 32, making it prone to deformation and affecting the safety performance of the secondary battery. If the dimension a of the venting channel 322 along the first direction Z is too small, the venting effect may be unsatisfactory, resulting in failure to release pressure smoothly, and even leading to the explosion of the secondary battery.

[0058] In some embodiments, the dimension b mm of the sidewall 3211 of the lower insulating member 32 along the first direction Z further satisfies: 1 ≤ b ≤ 15. The value of b can be any one or a range between any two values ​​from 1, 1.1, 1.2, 1.3, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15. If the dimension b mm of the sidewall 3211 along the first direction Z is too small, the dimension of the exhaust channel 322 along the first direction Z will be even smaller. In this case, no matter how the exhaust channel 322 is arranged, a good exhaust effect cannot be achieved, resulting in the inability to properly depressurize during thermal runaway of the secondary battery. If the dimension b mm of the side wall 3211 along the first direction Z is too large, the exhaust channel 322 can have multiple layout schemes, all of which can achieve a good exhaust effect. However, they will occupy more internal space of the secondary battery, resulting in a smaller overall volume of the electrode assembly 2, which leads to a smaller overall capacity of the secondary battery and affects the volumetric energy density of the secondary battery.

[0059] As shown in Figure 4, in some embodiments, the secondary battery has a third direction X that intersects the first direction Z and the second direction Y, respectively. Along the third direction X, the size of the exhaust channel 322 is c mm, where c satisfies: 0.5 ≤ c ≤ 10.

[0060] In this embodiment, the dimension c (mm) of the exhaust channel 322 along the third direction X can be any one of 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, or a range between any two values. If the dimension c of the exhaust channel 322 along the third direction X is too small, i.e., c < 0.5, when there is only one exhaust channel 322, the pressure relief area of ​​the exhaust channel 322 is too small. When there are multiple exhaust channels 322, since the dimension of each exhaust channel 322 along the third direction X is too small, the total area of ​​the multiple exhaust channels 322 is still small. Therefore, when the dimension of the exhaust channel 322 along the third direction X is too small, it cannot play the role of exhaust pressure relief, and there is a risk of secondary battery explosion. If the dimension c of the exhaust channel 322 along the third direction X is too large, i.e., c > 10, then the portion of the exhaust channel 322 enclosed by the side wall 3211 along the first direction Z is suspended, and the suspended dimension is too large, resulting in low mechanical strength and poor support strength. Under the condition of the secondary battery being used in reverse, the electrode assembly 2 is compressed by gravity against the lower insulating part 32, which is prone to deformation, causing the area of ​​the exhaust channel 322 to deform or partially close, failing to achieve the expected ventilation and pressure relief function. In severe cases, the lower insulating part 32 may be mechanically damaged and fail.

[0061] As shown in Figure 5, in some embodiments, along the second direction Y, the minimum dimension between the sidewall 3211 and the pressure relief component 311 is f mm, and the minimum distance between the pressure relief component 311 and the housing 1 is d mm, where f and d satisfy: 1≤(df)≤5.

[0062] In this embodiment, the sidewall 3211 forms a groove 321, which is located between the pressure relief member 311 and the housing 1. The orthographic projection of the pressure relief member 311 along the first direction Z onto the lower insulating member 32 falls entirely within the groove 321. This avoids obstructing the pressure relief member 311, thereby ensuring that the thermal runaway gas acts entirely on the pressure relief member 311. This facilitates the opening of the pressure relief member 311 to release pressure when the internal pressure of the secondary battery reaches a certain value.

[0063] It should be noted that, in this embodiment of the application, the minimum dimension between the side wall 3211 along the second direction Y and the pressure relief component 311 is f mm, and the minimum distance between the pressure relief component 311 along the second direction Y and the housing 1 is d mm. f and d satisfy: 1 ​​≤ (df) ≤ 5, which can ensure that the pressure relief component 311 can release pressure smoothly, and is conducive to reserving sufficient gap 4 width to allow the exhaust channel 322 to breathe smoothly. At the same time, it also ensures that the lower insulating component 32 has sufficient support area when the secondary battery is used upside down, thereby ensuring the stable performance of the secondary battery. Among them, the value range of (df) can be any one value or any two values ​​of 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.2, 2.5, 2.8, 3, 3.5, 4, 4.5, 5. If (df) < 1, the gap 4 between the corresponding side wall 3211 and the shell 1 is small, causing the exhaust channel 322 to be unable to vent smoothly. At the same time, the wall thickness of the side wall 3211 itself is small, and the overall support is poor. When the secondary battery is used upside down, the lower insulating component 32 is prone to deformation, or even mechanical failure. There may also be problems with normal battery production due to assembly interference. If (df) > 5, the corresponding dimension of the lower insulating component 32 in the second direction Y is too small. When the secondary battery is used upside down, the supporting area of ​​the lower insulating component 32 for the electrode assembly 2 is insufficient. Under vehicle vibration, the diaphragm may collapse due to insufficient support from the lower insulating component 32, resulting in short circuit of the electrode sheets, affecting the performance and safety of the secondary battery.

[0064] In some embodiments, along the second direction Y, the minimum dimension f mm between the sidewall 3211 and the pressure relief member 311 further satisfies: 1 ≤ f ≤ 45. The minimum distance d mm between the pressure relief member 311 and the housing 1 along the second direction Y further satisfies: 2 ≤ d ≤ 50. Wherein, the numerical range of f can be any one or any two values ​​from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45. The numerical range of d can be any one or any two values ​​from 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50.

[0065] It should also be noted that in the above embodiments, any one of dimensions a, b, c, d, e, and f 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, the above dimensions can also be measured using projection. For example, a projection measuring device (such as a digital microscope or image measuring instrument) can be used to acquire an image of the exhaust channel 322 and measure the corresponding dimensions.

[0066] In some embodiments, the sidewall 3211 is provided with a plurality of exhaust channels 322, and the total opening area of ​​the plurality of exhaust channels 322 is S1 mm. 2 The area of ​​the side wall 3211 facing the housing 1 along the second direction Y after removing multiple exhaust channels 322 is S2 mm. 2 S1 and S2 satisfy: 0.5≤S1 / S2≤5.

[0067] In some embodiments, the groove area of ​​the groove 321 is larger than the area of ​​the pressure relief member 311, thus avoiding any impact on the smooth pressure relief of the pressure relief member 311. The larger the total opening area of ​​the exhaust channel 322, the better the air permeability, thus achieving better and faster air permeability, and thereby enabling the pressure relief member 311 to release pressure quickly. Since the exhaust channel 322 is formed on the side wall 3211, the total opening area of ​​the exhaust channel 322 needs to be constrained by the side wall 3211. When the total opening area S1 of the multiple exhaust channels 322 and the remaining area S2 of the side wall 3211 after removing the exhaust channels 322 satisfy the range of 0.5≤S1 / S2≤5, the support of the lower insulating member 32 and the air permeability of the exhaust channel 322 can be guaranteed.

[0068] In some embodiments, the numerical range of S1 / S2 can be any one or any two values ​​from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, and 10. If the ratio of S1 / S2 is too small, the total opening area of ​​the exhaust channel 322 is too small, and the exhaust channel 322 cannot fully perform its function of ventilating and relieving pressure. If the ratio of S1 / S2 is too large, the total opening area of ​​the corresponding exhaust channel 322 is too large, and the remaining area of ​​the corresponding sidewall 3211 is too small. Consequently, the area of ​​the sidewall 3211 used to contact the top cover plate 31 for support is smaller, resulting in lower mechanical strength of the lower insulating member 32. When the secondary battery is used in reverse, the lower insulating component 32 is prone to deformation under the gravity of the electrode assembly 2, which causes the total opening area of ​​the exhaust channel 322 on the side wall 3211 to become smaller or partially closed, and cannot fully play the role of venting and depressurizing. In severe cases, it may lead to mechanical failure of the lower insulating component 32.

[0069] In some embodiments, the total opening area of ​​the plurality of exhaust channels 322 is S1 mm. 2 S1 satisfies: 50 ≤ S1 ≤ 2000. The area of ​​the sidewall 3211, after removing multiple exhaust channels 322, along the second direction Y towards the housing 1, is S2 mm. 2S2 satisfies: 50 ≤ S2 ≤ 800. The value of S1 can be any one or any two values ​​from 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, and 2000. The value of S2 can be any one or any two values ​​from 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 700, and 800. A larger S1 and a smaller S2 result in better exhaust performance of the exhaust channel 322, but may lead to lower mechanical strength of the lower insulating component 32.

[0070] In some embodiments, the bottom wall 3212 is provided with a plurality of through holes 323, which penetrate the bottom wall 3212 along a first direction Z and communicate with the groove 321. The total area of ​​the plurality of through holes 323 is S3 mm. 2 The area of ​​the pressure relief component 311 facing the bottom wall 3212 is S4 mm. 2 S3 and S4 satisfy: 1≤S3 / S4≤3.

[0071] In this embodiment, not only is ventilation and pressure relief achieved through the exhaust channel 322, but multiple through holes 323 can also be provided on the bottom wall 3212. Ventilation through these multiple through holes 323 allows the lower insulating member 32 to achieve better ventilation. Even when the battery is used upside down, with the electrode assembly 2 pressed against the bottom wall 3212 under gravity, some through holes 323 may still allow for smooth ventilation. Through the conduction of the through holes 323 and the exhaust channel 322, the lower insulating member 32 can achieve even better ventilation and pressure relief.

[0072] In some embodiments, the numerical range of S3 / S4 can be any one or any two of the following: 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3. If the ratio of S3 / S4 is too small (e.g., less than 1), the total area of ​​the multiple through holes 323 is smaller than the area of ​​the pressure relief component 311. In this case, the air permeability of the bottom wall 3212 is low, especially when the secondary battery is used in reverse, the multiple through holes 323 may be completely blocked by the electrode assembly 2, thus failing to provide air permeability. If the ratio of S3 / S4 is too large, it means that the area of ​​the multiple through holes 323 exposed to metal components may increase, which increases the risk of metal foreign objects contacting the top cover 31 and the electrode assembly 2, easily causing a short circuit risk.

[0073] In some embodiments, the total area S3 of the plurality of through holes 323 and the area S4 of the pressure relief member 311 facing the bottom wall 3212 further satisfy at least one of the following characteristics: 50≤S3≤6000, or 50≤S4≤2000. The value of S3 can be any one or a range between any two of the following: 50, 60, 70, 80, 100, 200, 300, 400, 500, 800, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000. The larger the value of S3, the better the air permeability of the corresponding plurality of through holes 323, which is more conducive to air permeability and pressure relief. When S3 < 50, the corresponding air permeability is low, which is not conducive to exhaust and pressure relief. When S3 > 6000, more metal area will be exposed, posing a risk that foreign metal objects can easily cross the top cover plate 31 and electrode assembly 2 through the through hole 323, leading to insulation failure. The value of S4 can be any one or any two values ​​from 50, 60, 70, 80, 100, 200, 300, 400, 500, 800, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000. The larger the value of S4, the faster the thermal runaway gas can be discharged from the secondary battery when the pressure relief component 311 bursts, resulting in higher pressure relief efficiency. If S4 is too large, the sidewall 3211 will not have enough space, resulting in poor overall support of the lower insulating member 32 when the secondary battery is used upside down. When the electrode assembly 2 is compressed by gravity, the lower insulating member 32 is prone to deformation, or even mechanical damage, leading to insulation failure. If S4 is too small, the pressure relief will be too slow, which cannot effectively guarantee the safety performance of the secondary battery. In some embodiments, the total area S3 of the plurality of through holes 323 and the area S4 of the pressure relief member 311 facing the bottom wall 3212 further satisfy at least one of the following characteristics: 50≤S3≤3000, or 50≤S4≤1500.

[0074] Please refer to Figures 8-10. Each through hole 323 can be a circular hole, an elliptical hole, a square hole, a diamond-shaped hole, etc., all of which can facilitate the smooth exhaust of the bottom wall 3212 of the groove 321.

[0075] This application also provides a battery pack, which may include the secondary battery provided in any of the foregoing embodiments. It is understood that the battery pack of this application includes all the technical features and effects of the aforementioned secondary batteries, and will not be repeated here.

[0076] Of course, the battery pack referred to in this application can be a battery module or an integrated battery pack without modules.

[0077] This application also provides an electrical device, which may include a secondary battery or a battery pack as provided in any of the foregoing embodiments. The secondary battery or battery pack is used to supply power to the electrical device. It is understood that the electrical device of this application includes all the technical features and effects of the aforementioned secondary battery, which will not be repeated here.

[0078] 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, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. 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, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0079] The secondary battery of this application will be described in detail below with reference to specific embodiments.

[0080] Table 1

[0081] Table 2

[0082] Please refer to Tables 1 and 2 above. Examples 1-24 in Table 1 correspond to Examples 1-24 in Table 2, and Comparative Examples 1-12 in Table 1 correspond to Comparative Examples 1-12 in Table 2.

[0083] As can be seen from the above embodiments and comparative examples, when the dimension 'a' of the exhaust channel 322 along the first direction Z and the dimension 'e' of the gap 4 along the second direction Y satisfy 1 ≤ e / a ≤ 4, the secondary battery can normally depressurize and exhaust gas during thermal runaway. When 'a' is 0.5 ≤ a ≤ 5 and 'e' is 0.5 ≤ e ≤ 10, the battery depressurization and cycle life are normal, and there will be no interference or mechanical damage. However, when 'a' is 0.4, the cycle life decreases. When 'a' is 10, it will affect depressurization and may even lead to an explosion. When 'e' is 0.2, the battery thermal runaway will delay valve opening, which poses an explosion risk. When 'e' is 20, the battery cycle life will decrease. Therefore, the preferred range for 'a' is 0.5 ≤ a ≤ 5, and the preferred range for 'e' is 0.5 ≤ e ≤ 10.

[0084] Under the condition of keeping 1≤e / a≤4, if the minimum distance d between the pressure relief component 311 and the housing 1 along the second direction Y and the minimum dimension f between the side wall 3211 and the pressure relief component 311 along the second direction Y can satisfy 1≤(df)≤5, then the support area of ​​the lower insulating component 32 on the electrode assembly 2 can be further guaranteed when the secondary battery is used in reverse, thereby maintaining the performance of the secondary battery, that is, guaranteeing the cycle life of the secondary battery when it is used in reverse.

[0085] While maintaining 1≤e / a≤4, further make 0.5≤S1 / S2≤5. At this time, while ensuring normal venting and depressurization of the battery, it can also ensure that the lower insulating part 32 will not be mechanically damaged due to the gravity of the electrode assembly 2 when the battery is used upside down.

[0086] While maintaining 1≤e / a≤4, further make 1≤S3 / S4≤3. At this time, while ensuring the normal venting and depressurization of the battery, it can prevent metal foreign objects from crossing the top cover plate 31 and electrode assembly 2 through multiple through holes 323, which would cause short circuit failure.

[0087] It should be noted that the normal pressure relief of the secondary battery shown in Tables 1 and 2 refers to the pressure relief component 311 (explosion-proof valve) opening to relieve pressure before the weld between the top cover plate 31 and the shell is damaged. The instances of abnormal pressure relief in the comparative examples are due to insufficient area of ​​the channel or orifice leading to the pressure relief component 311 (explosion-proof valve). This results in a slow airflow rate to the pressure relief component 311, meaning the internal pressure of the secondary battery has already reached the opening pressure of the pressure relief component 311 (explosion-proof valve), but has not yet been transmitted to the explosion-proof valve. Meanwhile, the weld between the top cover plate 31 and the shell has already been damaged due to excessive internal pressure (commonly known as an explosion). For example, the normal opening pressure value of the pressure relief component 311 is 0.9 ± 0.2 MPa. Within this internal pressure range, the secondary battery opens the explosion-proof valve to relieve pressure. If the internal pressure exceeds this range, the secondary battery does not explode, and the pressure relief component 311 (explosion-proof valve) opens to relieve pressure, which is considered delayed pressure relief. If the internal air pressure exceeds this range, and the pressure relief component 311 (explosion-proof valve) does not open, the weld between the top cover plate 31 and the outer shell will be damaged, which would constitute an explosion.

[0088] The method to test whether the pressure is released normally is as follows: Fix the large surface of the secondary battery with a clamp, process a vent hole on the secondary battery, pressurize the vent hole with a digital display press until the pressure relief component 311 (explosion-proof valve) opens, and record the pressure value on the press. This is the pressure relief value of the battery.

[0089] It should also be noted that whether assembly interference causes the battery to fail to be produced normally, as shown in Table 2, is related to (df) in Table 1. (df) is the distance between the side wall 3211 near the pressure relief component 311 and the housing 1. This value includes the wall thickness of the side wall 3211. If (df) is too small, the lower insulating component 32 will interfere with the inner wall of the housing 1 during assembly and cannot be assembled.

[0090] It should also be noted that when the secondary battery is used upside down, if the supporting area of ​​the lower insulating component 32 for the electrode assembly is too small, the performance of the secondary battery will decrease, resulting in a reduced battery cycle life. The normal cycle life of the battery is 2000 cycles. The specific test method for cycle life is as follows: at 25°C, the lithium-ion batteries prepared in the examples and comparative examples are charged at a 3C rate and discharged at a 1C rate, and a full charge-discharge cycle test is performed until the capacity of the lithium-ion battery decays to 90% of the initial capacity, and the number of cycles is recorded.

[0091] 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.

[0092] 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 having intersecting first direction (Z) and second direction (Y), the secondary battery comprising: The shell (1) has a receiving cavity (11); Electrode assembly (2) is disposed in the receiving cavity (11); as well as 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 covers the receiving cavity (11). The lower insulating member (32) is located in the receiving cavity (11) and connected to the top cover plate (31). The top cover plate (31) is provided with a pressure relief member (311). The lower insulating member (32) has a bottom wall (3212) and a side wall (3211). The bottom wall (3212) is spaced apart from the pressure relief member (311) along the first direction (Z). The side wall (3211) is connected to the periphery of the bottom wall (3212) to form a groove (321). The orthographic projection of the pressure relief member (311) along the first direction (Z) on the lower insulating member (32) is located in the groove (321). An exhaust channel (322) is provided on the side wall (3211) and extends through the side wall (3211) along the second direction (Y). A gap (4) is formed between the side wall (3211) and the housing (1) along the second direction (Y). The exhaust channel (322) communicates with the gap (4) and the groove (321) respectively. The dimension of the gap (4) along the second direction (Y) is e mm, and the dimension of the exhaust channel (322) along the first direction (Z) is a mm. The e and the a satisfy: 1≤e / a≤4.

2. The secondary battery according to claim 1, wherein, Along the first direction (Z), the dimension of the sidewall (3211) is b mm, where b and a satisfy: 0.5 ≤ (ba) ≤ 10.

3. The secondary battery according to claim 2, wherein, 0.5≤a≤5, and / or, 1≤b≤15.

4. The secondary battery according to claim 2, wherein, 1≤a≤3, and / or, 2≤b≤11.

5. The secondary battery according to claim 2, wherein, The secondary battery has a third direction (X) that intersects the first direction (Z) and the second direction (Y) respectively. Along the third direction (X), the size of the exhaust channel (322) is c mm, where c satisfies: 0.5≤c≤10.

6. The secondary battery according to claim 1, wherein, 0.5≤e≤10。 7. The secondary battery according to claim 1, wherein, Along the second direction (Y), the minimum dimension between the sidewall (3211) and the pressure relief component (311) is f mm, and the minimum distance between the pressure relief component (311) and the housing (1) is d mm, wherein f and d satisfy: 1≤(df)≤5.

8. The secondary battery according to claim 7, wherein, 1≤f≤45, and / or, 2≤d≤50.

9. The secondary battery according to claim 1, wherein, The sidewall (3211) is provided with a plurality of exhaust channels (322), and the total opening area of ​​the plurality of exhaust channels (322) is S1 mm. 2 The sidewall (3211), after removing the plurality of exhaust channels (322), has an area of ​​S2 mm on the side facing the housing (1) along the second direction (Y). 2 S1 and S2 satisfy: 0.5≤S1 / S2≤5.

10. The secondary battery according to claim 9, wherein, 50≤S1≤2000, and / or, 50≤S2≤800.

11. The secondary battery according to claim 1, wherein, The lower insulating member (32) is provided with a plurality of through holes (323), which penetrate the bottom wall (3212) along the first direction (Z) and communicate with the groove (321). The total area of ​​the plurality of through holes (323) is S3 mm. 2 The area of ​​the pressure relief component (311) facing the bottom wall (3212) is S4 mm. 2 S3 and S4 satisfy: 1≤S3 / S4≤3.

12. The secondary battery according to claim 11, wherein, 50≤S3≤6000, and / or, 50≤S4≤2000.

13. The secondary battery according to claim 11, wherein, 50≤S3≤3000, and / or, 50≤S4≤1500.

14. A battery pack comprising a secondary battery as described in any one of claims 1-13.

15. An electrical device comprising a secondary battery as described in any one of claims 1-13, or a battery pack as described in claim 14.

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