Battery cells, battery packs and electrical equipment

Abstract

The embodiments of the present application disclose a battery cell, a battery pack and an electrical device, belonging to the field of battery technology. The battery cell is provided with a pressure relief hole and an explosion-proof valve on the bottom wall of the shell, and a first flow channel and a second flow channel are provided on the bottom wall. The first flow channel extends along the circumferential edge of the bottom wall and is connected with the accommodating cavity, and the second flow channel is connected between the first flow channel and the pressure relief hole, so that exhaust space is reserved for the bottom of the battery cell through the first flow channel and the second flow channel. When the battery cell thermally runs away, the uncontrolled airflow can enter the second flow channel through the first flow channel at the edge, and converge at the pressure relief hole from the second flow channel, break through the pressure relief hole to achieve pressure relief; at the same time, the relevant parameters of the second flow channel and the pressure relief hole are satisfied so that when thermal runaway occurs, the airflow and pressure of the airflow converged at the pressure relief hole through the second flow channel are moderate, and the valve breaking time of the airflow breaking through the explosion-proof valve is moderate, thereby ensuring the stability and safety of the battery cell.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to battery cells, battery packs and electrical equipment. Background Art

[0002] Batteries are core components of new energy vehicles, mobile phones, laptops and other electrical equipment, and their safety performance is particularly important. At present, some batteries are equipped with explosion-proof valves at the bottom. However, due to gravity, the electrode components and bottom support plates inside the battery will occupy the bottom space. When thermal runaway occurs, the airflow cannot converge on the explosion-proof valve, making it impossible for the explosion-proof valve to release pressure in time, thus affecting the safety performance of the battery. Summary of the invention

[0003] Purpose of the invention: An embodiment of the present application provides a battery cell, aiming to overcome the technical problem that the explosion-proof valve at the bottom of the existing battery cell cannot release pressure in time; another purpose of the embodiment of the present application is to provide a battery pack; the third purpose of the embodiment of the present application is to provide an electrical device.

[0004] Technical solution: A battery cell according to an embodiment of the present application includes:

[0005] A shell, the shell has a first direction, the shell is provided with a receiving cavity with an opening at one end, the shell comprises a bottom wall, the bottom wall is located at an end of the receiving cavity away from the opening and is opposite to the opening along the first direction, and the bottom wall is provided with a pressure relief hole penetrating along the first direction;

[0006] an explosion-proof valve, the explosion-proof valve being connected to the bottom wall and covering the pressure relief hole;

[0007] A first flow channel and a plurality of second flow channels are provided on a side of the bottom wall facing the accommodating cavity, wherein the first flow channel extends along the circumferential edge of the bottom wall and is connected to the accommodating cavity, and the plurality of second flow channels are arranged around the explosion-proof valve at intervals, and the second flow channels are connected to the pressure relief hole and the first flow channel;

[0008] The second flow channel includes a first surface and a second surface opposite to each other, the first surface and the second surface are connected to the hole wall of the pressure relief hole, the minimum distance between the first surface and the second surface is 1 mm, the number of the second flow channels is , the maximum dimension of the second flow channel along the first direction is h mm, and the minimum cross-sectional area of ​​the pressure relief hole perpendicular to the first direction is S mm 2 ; The battery cell meets:

[0009]

[0010] In some embodiments, the battery cell satisfies at least one of the following conditions:

[0011] (1)

[0012] (2)75≤S≤1300;

[0013] (3)0.1≤h≤1.8.

[0014] In some embodiments, among the plurality of second flow channels, at least part of the second flow channels include:

[0015] A main flow channel, one end of which is connected to the pressure relief hole, and the other end of which is connected to the first flow channel;

[0016] A branch flow channel, one end of which is connected to the main flow channel, and the other end of which is connected to the first flow channel.

[0017] In some embodiments, the branch flow channel is provided in plurality;

[0018] The plurality of branch flow channels all extend in the same direction, or the extending directions of at least two of the branch flow channels intersect.

[0019] In some embodiments, a plurality of the second flow channels extend in a divergent manner around the pressure relief hole.

[0020] In some embodiments, the bottom wall comprises:

[0021] a convex portion, wherein the pressure relief hole and the second flow channel are both arranged on the convex portion;

[0022] The peripheral portion is connected to the circumferential edge of the convex portion in a surrounding manner, and the convex portion is protruded toward the accommodating cavity relative to the peripheral portion.

[0023] In some embodiments, a groove is provided on a side of the bottom wall facing away from the accommodating cavity, and the peripheral portion and the convex portion form the groove.

[0024] In some embodiments, the housing further comprises:

[0025] A plurality of side walls are sequentially connected and surround the circumferential edge of the peripheral portion, the plurality of side walls are spaced apart from the convex portion, and the first flow channel is arranged between the convex portion and the plurality of side walls.

[0026] Accordingly, a battery pack described in an embodiment of the present application includes the battery cell described in any of the above embodiments.

[0027] Correspondingly, an electrical device described in an embodiment of the present application includes the battery pack described above.

[0028] Beneficial effect: The battery cell of the embodiment of the present application is provided with a pressure relief hole and an explosion-proof valve on the bottom wall of the shell, and a first flow channel and a second flow channel are provided on the bottom wall, the first flow channel extends along the circumferential edge of the bottom wall and is connected with the accommodating cavity, and the second flow channel is connected between the first flow channel and the pressure relief hole, so that exhaust space is reserved for the bottom of the battery cell through the first flow channel and the second flow channel. When the battery cell is thermally runaway, the out-of-control airflow can enter the second flow channel through the first flow channel at the edge, and converge at the pressure relief hole from the second flow channel, breaking through the pressure relief hole to achieve pressure relief; at the same time, the relevant parameters of the second flow channel and the pressure relief hole meet In the event of thermal runaway, the air flow rate and pressure of the airflow converging at the pressure relief hole through the second flow channel are moderate, and the time it takes for the airflow to break through the explosion-proof valve is moderate, thereby ensuring the stability and safety of the battery cell.

[0029] The battery pack of the embodiment of the present application may include all the technical features and beneficial effects of the above-mentioned battery cells, which will not be repeated here.

[0030] The electrical equipment of the embodiment of the present application may include all the technical features and beneficial effects of the above-mentioned battery pack, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 An exploded schematic diagram of parts of a battery cell provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of an exploded view of a battery cell provided in an embodiment of the present application when viewed from another angle;

[0034] Figure 3 A schematic diagram of the three-dimensional structure of a housing of a battery cell provided in the first embodiment of the present application;

[0035] Figure 4 for Figure 3 A schematic diagram of the main structure of the housing of the battery cell;

[0036] Figure 5 for Figure 4 A schematic diagram of the rear view structure of the housing of the battery cell;

[0037] Figure 6 For along Figure 5 Schematic diagram of the cross-sectional structure along the AA line;

[0038] Figure 7 For along Figure 5 Schematic diagram of the cross-sectional structure along the middle BB line;

[0039] Figure 8 for Figure 7 A schematic diagram of the local enlarged structure of the middle A area;

[0040] Fig. 9 A schematic diagram of the front structure of a housing of a battery cell provided in a second embodiment of the present application;

[0041] Fig.10 for Fig. 9 A schematic diagram of the rear view structure of the housing of the battery cell;

[0042] Fig.11 For along Fig.10 Schematic diagram of the cross-sectional structure of the CC line;

[0043] Fig.12 For along Fig.10 Schematic diagram of the cross-sectional structure of the middle DD line;

[0044] Fig.13 for Fig.12 A schematic diagram of the local enlarged structure of the middle B area;

[0045] Figure markings: 100-shell; 110-accommodating chamber; 111-opening; 120-bottom wall; 121-first flow channel; 122-second flow channel; 123-main flow channel; 124-branch flow channel; 125-first surface; 126-second surface; 127-convex portion; 128-peripheral portion; 129-groove; 130-pressure relief hole; 140-side wall; 200-explosion-proof valve; 300-top cover assembly; 400-electrode assembly; 500-support plate; 600-insulating film. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0047] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined.

[0048] The applicant noted that the existing battery cell structure is to push out the positive / negative poles and the pressure relief device. This structural form has certain limitations on the electrical connection between batteries and the exhaust safety. Therefore, the battery cell with a pressure relief device at the bottom of the aluminum shell came into being. However, the bottom pressure relief device requires that the bottom of the battery cell has sufficient exhaust space to ensure that the airflow in the shell cavity can converge at the bottom pressure relief device position. Due to the influence of gravity on the electrode assembly and the bottom support plate, the airflow often cannot converge at the pressure relief device, resulting in the failure to release pressure in time, affecting the safety performance of the battery cell.

[0049] In view of this, an embodiment of the present application provides a battery cell to overcome at least one of the above technical problems.

[0050] See also Figure 1 and Figure 2 It should be noted that, in the battery cell provided in the embodiment of the present application, the applicant mainly improves the structure of the shell 100 and the arrangement position of the explosion-proof valve 200, and the following focuses on the improved parts.

[0051] It should also be noted that, in addition to the improved structure described above, the battery cell may also include components such as a top cover assembly 300, an electrode assembly 400, a support plate 500, and an insulating film 600. The top cover assembly 300 is connected to the shell 100 and sealed at the opening of the shell 100, the electrode assembly 400 is disposed in the accommodating cavity 110 of the shell 100, the support plate 500 is disposed on the side of the electrode assembly 400 away from the top cover assembly 300, and is used to support the electrode assembly 400 from below, and the insulating film 600 is coated on the outside of the shell 100 to provide insulation protection.

[0052] Please combine Figure 1 and Figure 3The shell 100 has a first direction X, and the shell 100 is provided with a accommodating cavity 110 having an opening 111 at one end. The shell 100 includes a bottom wall 120, and the bottom wall 120 is located at one end of the accommodating cavity 110 away from the opening 111, and is opposite to the opening 111 along the first direction X. That is to say, the opening 111 and the bottom wall 120 are respectively arranged at two opposite ends of the shell 100 in the first direction X. For the usual placement of the battery cell, the opening 111 is located at the upper end, and the bottom wall 120 is located at the lower end.

[0053] It should be noted that in the present invention, the first direction X is the height direction of the housing 100. Figure 1-2 .

[0054] The bottom wall 120 is provided with a pressure relief hole 130 penetrating along the first direction X. The explosion-proof valve 200 is connected to the bottom wall 120 and covers the pressure relief hole 130. That is, the explosion-proof valve 200 of the pressure relief device of the battery cell targeted by the present application exhausts gas toward the bottom.

[0055] In the embodiment of the present application, the side of the bottom wall 120 facing the accommodating chamber 110 is provided with a first flow channel 121 and a plurality of second flow channels 122. The first flow channel 121 extends along the circumferential edge of the bottom wall 120 and is connected to the accommodating chamber 110. That is, the first flow channel 121 is an annular flow channel, which is arranged around the edge of the bottom wall 120. The plurality of second flow channels 122 are arranged around the explosion-proof valve 200 at intervals from each other. The second flow channels 122 are connected to the pressure relief hole 130 and the first flow channels 121. That is, the plurality of second flow channels 122 are arranged at intervals from each other along the circumference of the pressure relief hole 130, and any two second flow channels 122 are spaced from each other. It should be noted that in the description of the present application, the second flow channels 122 connected to the pressure relief hole 130 are collectively referred to as a second flow channel 122. The second flow channel 122 may have a fork or may not have a fork. Regardless of the form of its structure, as long as it is connected to the pressure relief hole 130 at one place, it can be identified as a second flow channel 122.

[0056] For details, please refer to Figure 4 In the embodiment of the present application, the second flow channel 122 includes a first surface 125 and a second surface 126 opposite to each other, the first surface 125 and the second surface 126 are respectively connected to the hole wall of the pressure relief hole 130, the minimum spacing between the first surface 125 and the second surface 126 is 1 mm, the number of the second flow channels 122 is x, the maximum dimension of the second flow channel 122 along the first direction X is h mm, and the minimum cross-sectional area of ​​the pressure relief hole 130 perpendicular to the first direction X is S mm 2 ; Battery cells meet the following requirements:

[0057]

[0058] By setting the relevant parameters of the second flow channel 122 and the pressure relief hole 130 to satisfy the above relationship, when the battery cell is in thermal runaway, the air flow rate and pressure of the airflow converged at the pressure relief hole 130 through the second flow channel 122 are moderate, so that the time for the airflow to break through the explosion-proof valve is moderate, thereby ensuring the stability and safety of the battery cell.

[0059] Specifically, It can be any value among 1.1, 2.0, 6.0, 10, 20, 30, 40, 50, 65 or a range between any two values. When the battery cell in thermal runaway breaks, the time it takes for the valve to rupture is relatively fast, leaving too little time for the driver to react, which reduces the safety of the battery pack and is not conducive to ensuring the driver's personal safety; when When the battery cell with thermal runaway fails, the valve rupture time of the battery cell is relatively slow. Although it gives the electric vehicle driver more reaction time, if the high-temperature gas inside the battery cell with thermal runaway cannot be removed in time, the battery cell with thermal runaway will explode or deflagrate, which also reduces the safety of the battery pack and is not conducive to ensuring the personal safety of the driver. At this time, the airflow rate and pressure of the airflow converged at the pressure relief hole 130 through the second flow channel 122 are moderate, so that the time for the airflow to break through the explosion-proof valve is moderate, thereby ensuring the stability and safety of the battery cell.

[0060] It should be noted that the number x of the second flow channels 122 can be directly counted, and as long as it is connected to the pressure relief hole 130 at one place, it can be identified as one second flow channel 122. For example, in the first and second embodiments of the present application, there are four second flow channels 122. In other embodiments, the number of the second flow channels 122 can be set according to actual needs.

[0061] It should be noted that, in the present invention, the first flow channel 121 and the second flow channel 122 both refer to flow channel grooves, the first surface 125 and the second surface 126 are two side walls of the second flow channel 122, and the minimum spacing l mm between the first surface 125 and the second surface 126 and the maximum dimension h mm of the second flow channel 122 along the first direction X can be measured by conventional measuring devices such as a vernier caliper or a micrometer. Among them, the minimum spacing l between the first surface 125 and the second surface 126 is generally obtained by measuring the spacing from the connection between the first surface 125 or the second surface 126 and the hole wall of the pressure relief hole 130 to the other opposite surface, that is, a vertical line is drawn from one of the connections to the other opposite surface, the length of the vertical line is measured, and the length of the vertical line is taken as the minimum spacing l. It should be noted that the other end of the perpendicular line must be within the relative first surface 125 or the second surface 126. If the perpendicular lines drawn through the two connections to the relative first surface 125 or the second surface 126 respectively fail to fall within the relative surface, the distance between the two connections between the first surface 125, the second surface 126 and the hole wall of the pressure relief hole 130 is directly measured, and the distance is taken as the minimum distance l. For multiple second flow channels 122, after the minimum distance l of each second flow channel 122 is measured, the minimum value is selected as the final minimum distance l.

[0062] It should be noted that the minimum cross-sectional area of ​​the pressure relief hole 130 along the direction perpendicular to the first direction X is S mm. 2 The area can be measured by conventional area measurement means. When the minimum cross-section of the pressure relief hole 130 is a regular shape such as a circle or an ellipse, the area S can be measured and calculated by the area measurement means of a regular shape. When the minimum cross-section of the pressure relief hole 130 is an irregular shape, it can be measured and calculated by the coating method, that is, a coating with uniform mass is attached to the minimum cross-section, the coating attached to the corresponding part is removed, and the mass of the coating is determined. The quotient of the mass of the removed coating and the mass per unit area of ​​the coating that has been predetermined is determined as the area S of the measured minimum cross-section.

[0063] Furthermore, in some embodiments, the battery cell satisfies:

[0064]

[0065] That is, the minimum distance between the first surface 125 and the second surface 126 is By controlling the minimum spacing within the above range, it is possible to further ensure that the airflow rate and pressure of the second flow channel 122 converging at the pressure relief hole 130 are moderate, thereby ensuring the safety of the battery cell, wherein π=3.14.

[0066] Specifically, in some embodiments, the battery cell satisfies:

[0067] 75≤S≤1300.

[0068] That is to say, the minimum cross-sectional area S of the pressure relief hole 130 along the direction perpendicular to the first direction X can be any value among 75, 100, 300, 500, 700, 900, 1100, 1300 or a range between any two values, in units of mm 2 , controlling the area of ​​the pressure relief hole 130 within the above range can meet the exhaust requirements of battery cells of most electrical equipment.

[0069] Specifically, in some embodiments, the battery cell satisfies:

[0070] 0.1≤h≤1.8.

[0071] That is to say, the maximum dimension h of the second flow channel 122 along the first direction X can be any value among 0.1, 0.2, 0.4, 0.6, 0.7, 0.9, 1.0, 1.1, 1.2, 1.4, 1.5, 1.6, 1.7, 1.8, or a range value between any two values. By controlling h within this range, it can further ensure that the air flow rate and pressure of the second flow channel 122 converging at the pressure relief hole 130 are moderate, thereby ensuring the safety of the battery cell.

[0072] Please also read Figures 4 to 6 , Figures 9 to 11 In the first and second embodiments of the present application, multiple second flow channels 122 are included, wherein at least part of the second flow channels 122 include a main flow channel 123 and a branch flow channel 124, one end of the main flow channel 123 is connected to the pressure relief hole 130, and the other end is connected to the first flow channel 121, and one end of the branch flow channel 124 is connected to the main flow channel 123, and the other end is connected to the first flow channel 121. By providing the branch flow channel 124, the airflow can enter the second flow channel 122 faster and more evenly through the first flow channel 121, ensuring smooth pressure relief and improving safety.

[0073] Furthermore, in some embodiments, there are multiple branch flow channels 124; the multiple branch flow channels 124 all extend in the same direction, or the extension directions of at least two branch flow channels 124 intersect. For example, in the first embodiment, the branch flow channels 124 are connected to the main flow channel 123 in a divergent manner, and their extension directions must intersect. In the second embodiment, the branch flow channels 124 are all extended in a direction perpendicular to the main flow channel 123. By reasonably setting the extension direction of the branch flow channels 124, the distribution uniformity of the second flow channel 122 in the circumferential direction of the first flow channel 121 can be improved, thereby ensuring smooth exhaust and further improving safety.

[0074] Please refer again Figure 4In some embodiments, the plurality of second flow channels 122 extend in a divergent manner around the pressure relief hole 130. Thus, the second flow channels 122 can be evenly distributed around the first flow channel 121, and the airflow from each area around the first flow channel 121 can quickly enter the second flow channel 122 and merge into the pressure relief hole 130, thereby improving safety.

[0075] Please also read Figures 5 to 8 , Figure 10 to Figure 13 In some embodiments, the bottom wall 120 includes a protrusion 127 and a peripheral portion 128, the pressure relief hole 130 and the second flow channel 122 are both arranged on the protrusion 127, the peripheral portion 128 is surrounded and connected to the circumferential edge of the protrusion 127, and the protrusion 127 is protruded toward the accommodating cavity 110 relative to the peripheral portion 128.

[0076] Furthermore, a groove 129 is provided on the side of the bottom wall 120 away from the accommodating cavity 110, and the peripheral portion 128 and the convex portion 127 enclose the groove 129. In other words, the groove 129 is formed by the convex portion 127 and the groove 129, and is provided on the side of the convex portion 127 away from the groove 129. By providing the groove 129, the thickness of the bottom wall 120 at the convex portion 127 is prevented from being too thick, thereby reducing the weight of the battery cell.

[0077] Furthermore, the housing 100 further includes:

[0078] A plurality of side walls are sequentially connected and surround the circumferential edge of the peripheral portion 128 , the plurality of side walls are spaced apart from the convex portion 127 , and the first flow channel 121 is disposed between the convex portion 127 and the plurality of side walls.

[0079] Next, specific embodiments of the battery cells of the present application are provided, and the present application is described in more detail through the specific embodiments. It can be seen from the following embodiments that in actual implementation, when the battery cells satisfy the relationship of the present application, their safety is in an optimal state.

[0080] Example 1: The battery cell is a square lithium iron phosphate battery (in other embodiments, a ternary battery, a sodium ion battery, a solid-state or semi-solid-state battery type may also be used), and the poles of each battery cell are arranged on the top cover assembly 300, and the pressure relief hole 130 and the explosion-proof valve 200 are arranged on the bottom wall 120 of the shell 100. The electrode assembly 400 and the support plate 500 are arranged in the shell 100. The support plate 500 is located between the bottom wall 120 and the electrode assembly 400, and the electrode assembly 400 is supported by the support plate 500.

[0081] The structures of Examples 2 to 10 and Comparative Examples 1 to 3 are substantially the same as that of Example 1, except for the values ​​of the relevant parameters of the second flow channel 122 and the pressure relief hole 130 .

[0082] The details are as follows:

[0083]

[0084] From the table above we can see that:

[0085] when When the battery cell with thermal runaway breaks the valve relatively quickly, specifically, the time for comparative example 2 to break the valve is only 5.3s. The time for the battery cell with thermal runaway to break the valve is relatively fast, which leaves too little time for the driver of the electric vehicle to react, and the safety of the battery pack is reduced, which is not conducive to ensuring the personal safety of the driver.

[0086] when When the battery cell with thermal runaway has a relatively slow valve rupture time, specifically, comparative examples 1 and 3, the rupture times are 20s and 18.7s respectively. The battery cell with thermal runaway has a relatively slow valve rupture time, which gives the electric vehicle driver more reaction time. However, if the high-temperature gas inside the battery cell with thermal runaway cannot be removed in time, the battery cell with thermal runaway will explode or deflagrate, which also reduces the safety of the battery pack and is not conducive to ensuring the personal safety of the driver.

[0087] when Specifically looking at Examples 1-10, the valve rupture time of the battery cell that experiences thermal runaway is between 14s and 16.2s, and the valve rupture time of the airflow breaking through the explosion-proof valve is moderate, thereby ensuring the stability and safety of the battery cell, and giving the electric vehicle driver relatively more reaction time to escape.

[0088] Accordingly, an embodiment of the present application provides a battery pack, which includes a battery cell of any of the above embodiments. It can be understood that the battery pack can include all the technical features and beneficial effects of the above battery cells, which will not be repeated here.

[0089] Correspondingly, an embodiment of the present application provides an electrical device, which may be various types of equipment such as new energy vehicles, computers, energy storage power supply devices, etc. It can be understood that the electrical device may include all the technical features and beneficial effects of the above-mentioned battery pack, which will not be repeated here.

[0090] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0091] The battery pack and electrical equipment provided in the embodiments of the present application are introduced in detail above, and the principles and implementation methods of the present application are explained by using specific examples. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: A shell, the shell has a first direction, the shell is provided with a receiving cavity with an opening at one end, the shell comprises a bottom wall, the bottom wall is located at an end of the receiving cavity away from the opening and is opposite to the opening along the first direction, and the bottom wall is provided with a pressure relief hole penetrating along the first direction; an explosion-proof valve, the explosion-proof valve being connected to the bottom wall and covering the pressure relief hole; A first flow channel and a plurality of second flow channels are provided on a side of the bottom wall facing the accommodating cavity, wherein the first flow channel extends along the circumferential edge of the bottom wall and is connected to the accommodating cavity, and the plurality of second flow channels are arranged around the explosion-proof valve at intervals, and the second flow channels are connected to the pressure relief hole and the first flow channel; The second flow channel includes a first surface and a second surface opposite to each other, the first surface and the second surface are connected to the hole wall of the pressure relief hole, the minimum spacing between the first surface and the second surface is 1 mm, the number of the second flow channels is x, the maximum dimension of the second flow channel along the first direction is h mm, and the minimum cross-sectional area of ​​the pressure relief hole perpendicular to the first direction is S mm 2 ; The battery cell meets:

2. The battery cell according to claim 1, characterized in that: The battery cell meets at least one of the following conditions: (1) (2)75≤S≤1300； (3)0.1≤h≤1.8。 3. The battery cell according to claim 1, characterized in that: Among the plurality of the second flow channels, at least part of the second flow channels include: A main flow channel, one end of which is connected to the pressure relief hole, and the other end of which is connected to the first flow channel; A branch flow channel, one end of which is connected to the main flow channel, and the other end of which is connected to the first flow channel.

4. The battery cell according to claim 3, characterized in that: There are multiple branch flow channels; The plurality of branch flow channels all extend in the same direction, or the extending directions of at least two of the branch flow channels intersect.

5. The battery cell according to claim 1, characterized in that: The plurality of second flow channels extend in a divergent manner around the pressure relief hole with the pressure relief hole as the center.

6. The battery cell according to claim 1, characterized in that: The bottom wall comprises: a convex portion, wherein the pressure relief hole and the second flow channel are both arranged on the convex portion; The peripheral portion is connected to the circumferential edge of the convex portion in a surrounding manner, and the convex portion is protruded toward the accommodating cavity relative to the peripheral portion.

7. The battery cell according to claim 6, characterized in that: A groove is provided on a side of the bottom wall facing away from the accommodating cavity, and the peripheral edge portion and the convex portion surround the groove.

8. The battery cell according to claim 6, characterized in that: The housing further comprises: A plurality of side walls are sequentially connected and surround the circumferential edge of the peripheral portion, the plurality of side walls are spaced apart from the convex portion, and the first flow channel is arranged between the convex portion and the plurality of side walls.

9. A battery pack, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 8.

10. An electrical device, characterized in that: A battery pack comprising the battery pack of claim 9.

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