Cylindrical battery monomer, battery device and power utilization device

Abstract

The utility model provides a cylindrical battery cell, a battery device and an electric device. The cylindrical battery monomer comprises a shell, an electrode assembly and an electrode terminal, the shell is provided with a first wall part, the electrode assembly is at least partially accommodated in the shell, and the electrode assembly comprises a tab. The electrode terminal is disposed on the first wall portion, and the electrode terminal is electrically connected to the tab. The first wall part is provided with a weak part, and the weak part is configured to be capable of being damaged when the cylindrical battery monomer is subjected to pressure relief, so that at least part of the first wall part is opened and drives the electrode terminal to move, and at least part of the connection position of the electrode terminal and the tab is damaged. And the first wall part can be at least partially opened when the cylindrical battery monomers are decompressed, so that emissions can be conveniently discharged to the outside. The electrode terminal is driven by the first wall part to displace, so that at least part of the connection position of the electrode terminal and the tab is damaged, the overcurrent capacity between the electrode terminal and the tab is reduced, further development of thermal runaway can be inhibited, and the reliability of the cylindrical battery monomer can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular to a cylindrical battery monomer, a battery device and a power utilization device. BACKGROUND

[0002] Batteries are widely used in the field of new energy, for example, electric vehicles, new energy vehicles, etc. New energy vehicles and electric vehicles have become a new trend in the development of the automobile industry. The development of battery technology needs to consider various design factors, such as battery life, energy density, discharge capacity, charge-discharge rate, and other performance parameters. In addition, the reliability of the battery also needs to be considered. However, the reliability of the current battery is poor. CONTENT OF THE INVENTION

[0003] The purpose of the embodiments of the present application is to provide a cylindrical battery monomer, a battery device and a power utilization device, which aims to improve the problem of poor reliability of the battery in the related art.

[0004] In a first aspect, the embodiments of the present application provide a cylindrical battery monomer, which comprises a shell, an electrode assembly and an electrode terminal, the shell has a first wall part; the electrode assembly is at least partially accommodated in the shell, the electrode assembly comprises a tab; the electrode terminal is arranged on the first wall part, and the electrode terminal is electrically connected with the tab; wherein the first wall part has a weak part, the weak part is configured to be damaged when the cylindrical battery monomer is depressurized, so that at least part of the first wall part is opened, and the first wall part can drive the electrode terminal to move in a direction away from the tab when the first wall part is opened, so that the connection position of the electrode terminal and the tab is at least partially damaged.

[0005] In the above technical solution, the first wall part of the cylindrical battery monomer can be split along at least part of the weak part when the cylindrical battery monomer is depressurized, so that the first wall part is at least partially opened, thereby facilitating the discharge of the discharge material in the cylindrical battery monomer to the outside, and realizing depressurization. In this process, the electrode terminal is displaced under the driving of the first wall part, so that the connection position of the electrode terminal and the tab is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal and the tab, which is conducive to inhibiting the further development of thermal runaway and improving the reliability of the cylindrical battery monomer.

[0006] As an optional technical solution of the embodiments of the present application, the first wall part can cause the electrode terminal and the tab to be disconnected when the first wall part is opened.

[0007] In the technical solution, the first wall part can be at least partially opened when the cylindrical battery cell is depressurized, thereby driving the electrode terminal to move in a direction away from the tab, causing the electrical connection between the electrode terminal and the tab to fail, thereby breaking the circuit between the electrode terminal and the tab, and more favorably preventing further development of thermal runaway and improving the reliability of the cylindrical battery cell.

[0008] As an optional technical solution of the embodiment, the weak part is arranged around the electrode terminal.

[0009] In the technical solution, the weak part is arranged around the electrode terminal, so that the first wall part is relatively weak around the electrode terminal. When the cylindrical battery cell is depressurized, the first wall part around the electrode terminal is more likely to locally deform or locally separate, thereby facilitating displacement of the electrode terminal, causing the electrical connection between the electrode terminal and the electrode assembly to fail, causing the cylindrical battery cell to break the circuit when depressurized, thereby preventing further development of thermal runaway and improving the reliability of the cylindrical battery cell.

[0010] As an optional technical solution of the embodiment, the first wall part has a pressure relief part, the electrode terminal is arranged in the pressure relief part, and the weak part is an annular structure arranged around the pressure relief part and the electrode terminal.

[0011] In the technical solution, when the weak part is an annular structure, the first wall part is more likely to crack along the weak part as a whole when the cylindrical battery cell is depressurized, causing the pressure relief part to be more likely to flip open or separate from the first wall part, thereby opening a larger opening for pressure relief, which is conducive to improving the timeliness of pressure relief of the cylindrical battery cell and improving the reliability of the cylindrical battery cell. In addition, when the pressure relief part flips open or separates from the first wall part, the electrode terminal is displaced to a greater extent, which is more likely to cause the electrical connection between the electrode terminal and the electrode assembly to fail, thereby preventing further development of thermal runaway and improving the reliability of the cylindrical battery cell.

[0012] As an optional technical solution of the embodiment, the weak part is a circular ring.

[0013] In the technical solution, when the weak part is a circular ring, the weak part is more uniformly stressed at each position, and the first wall part is more likely to crack along the entire circumference of the weak part when the cylindrical battery cell is depressurized, causing the pressure relief part to be more likely to separate from the first wall part, thereby opening a larger opening for pressure relief, which is conducive to improving the timeliness of pressure relief of the cylindrical battery cell and improving the reliability of the cylindrical battery cell. In addition, when the pressure relief part separates from the first wall part, the electrode terminal is displaced to a greater extent, which is more likely to cause the electrical connection between the electrode terminal and the electrode assembly to fail, thereby preventing further development of thermal runaway and improving the reliability of the cylindrical battery cell.

[0014] As an optional technical solution of the embodiment of the present application, the area of the normal projection of the pressure relief part along the axial direction of the cylindrical battery monomer is S1, and the area of the normal projection of the first wall part is S2, and the following is met: 10%≤S1 / S2≤90%.

[0015] In the above technical solution, when S1 / S2≥10%, the area of the normal projection of the pressure relief part along the axial direction of the cylindrical battery monomer is relatively large, so that the pressure relief part is easily affected by the discharge inside the cylindrical battery monomer, thereby opening in time when the cylindrical battery monomer is pressure relieved, which is beneficial to improving the timeliness of the pressure relief of the cylindrical battery monomer. When S1 / S2≤90%, the area of the normal projection of the pressure relief part along the axial direction of the cylindrical battery monomer is not too large, which can reduce the risk of the weak part being cracked due to the change of the gas pressure inside the cylindrical battery monomer, and is beneficial to improving the reliability of the cylindrical battery monomer. Therefore, when 10%≤S1 / S2≤90%, the timeliness and reliability of the pressure relief of the battery monomer can be considered.

[0016] As an optional technical solution of the embodiment of the present application, 20%≤S1 / S2≤55%.

[0017] In the above technical solution, when S1 / S2≥20%, the area of the normal projection of the pressure relief part along the axial direction of the cylindrical battery monomer is larger, so that the pressure relief part is more easily affected by the discharge inside the cylindrical battery monomer, thereby opening in time when the cylindrical battery monomer is pressure relieved, which is more beneficial to improving the timeliness of the pressure relief of the cylindrical battery monomer. When S1 / S2≤55%, the area of the normal projection of the pressure relief part along the axial direction of the cylindrical battery monomer is not too large, which can reduce the risk of the weak part being cracked due to the change of the gas pressure inside the cylindrical battery monomer, and is beneficial to improving the reliability of the cylindrical battery monomer. Therefore, when 20%≤S1 / S2≤55%, the timeliness and reliability of the pressure relief of the battery monomer can be considered.

[0018] As an optional technical solution of the embodiment of the present application, the first wall part is provided with a plurality of weak parts, and the plurality of weak parts are arranged along the radial direction of the cylindrical battery monomer.

[0019] In the above technical solution, by arranging a plurality of weak parts, the plurality of weak parts are sequentially arranged around the electrode terminal along the radial direction of the cylindrical battery monomer, and when the cylindrical battery monomer is pressure relieved, the first wall part is more easily opened at least partially, thereby driving the electrode terminal to move away from the lug, so that the connection position of the electrode terminal and the lug is at least partially damaged, the overcurrent capacity between the electrode terminal and the lug is reduced, thereby inhibiting the further development of thermal runaway, and the reliability of the cylindrical battery monomer is improved.

[0020] As an optional technical solution of the embodiment of the present application, the weak part comprises a plurality of weak segments, and the plurality of weak segments are arranged at intervals along the circumferential direction of the cylindrical battery monomer.

[0021] In the technical solution, the plurality of weak sections are arranged along the circumference of the cylindrical battery cell, and the first wall portion can be cracked along at least one weak section when the cylindrical battery cell is depressurized, so that the first wall portion is at least partially opened to facilitate the discharge of the discharge material in the cylindrical battery cell to the outside, thereby achieving pressure relief. In this process, the electrode terminal is displaced under the action of the first wall portion, so that the connection position of the electrode terminal and the tab is at least partially destroyed, thereby reducing the overcurrent capacity between the electrode terminal and the tab, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell. Along the circumference of the cylindrical battery cell, the part of the first wall portion between the two adjacent weak sections has a higher strength, which is beneficial to reduce the risk of cracking of the weak section due to the change of the internal gas pressure of the cylindrical battery cell, and is beneficial to improve the reliability of the cylindrical battery cell.

[0022] As an optional technical solution of the embodiment of the present application, the first wall portion is provided with a first groove, and the first groove includes a plurality of groove sections, and the plurality of groove sections are arranged along the circumference of the cylindrical battery cell. The groove bottom wall of each groove section forms a weak section.

[0023] In the technical solution, the weak section is formed on the first wall portion by opening the first groove on the first wall portion. The first groove can include a plurality of groove sections arranged along the circumference of the cylindrical battery cell, and the groove bottom wall of each groove section corresponds to form a weak section. The first wall portion can be cracked along at least one groove section when the cylindrical battery cell is depressurized, so that the first wall portion is at least partially opened to facilitate the discharge of the discharge material in the cylindrical battery cell to the outside, which is simple, convenient and low in cost.

[0024] As an optional technical solution of the embodiment of the present application, the groove section extends along the circumference of the cylindrical battery cell, and along the circumference of the cylindrical battery cell, the first wall portion is configured to crack along the groove section and tear the part of the first wall portion between the two adjacent groove sections when the cylindrical battery cell is depressurized.

[0025] In the technical solution, the groove section extends along the circumference of the cylindrical battery cell, and the first wall portion can be cracked along at least one groove section when the cylindrical battery cell is depressurized, and then tear the part of the first wall portion between the two groove sections along the circumference of the cylindrical battery cell, thereby opening a larger opening to facilitate the discharge of the discharge material in the cylindrical battery cell to the outside. In this process, the electrode terminal is displaced under the action of the first wall portion, so that the connection position of the electrode terminal and the tab is at least partially destroyed, thereby reducing the overcurrent capacity between the electrode terminal and the tab, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell.

[0026] As an optional technical solution of the embodiment of the present application, the first wall portion is provided with a lead-out hole, the electrode terminal is at least partially threaded in the lead-out hole, and a plurality of groove segments are arranged around the lead-out hole; the groove segments extend in the radial direction of the cylindrical battery monomer, and the first wall portion is configured to be torn apart from the lead-out hole and torn along at least part of the groove segments when the cylindrical battery monomer is depressurized.

[0027] In the above technical solution, by making the groove segments extend in the radial direction of the cylindrical battery monomer, the first wall portion can be torn apart from the position of the lead-out hole where the electrode terminal is arranged first when the cylindrical battery monomer is depressurized, and then the first wall portion can be torn along the extension direction of the groove segments, thereby opening a larger opening to facilitate the discharge of the discharge material in the cylindrical battery monomer to the outside. In this process, the electrode terminal can not only be displaced under the action of the first wall portion, but also be moved outward under the action of the discharge material, so that the connection position of the electrode terminal and the tab is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal and the tab, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery monomer.

[0028] As an optional technical solution of the embodiment of the present application, the groove segment is an equal-width groove extending along a straight-line trajectory.

[0029] In the above technical solution, by arranging the groove segment as an equal-width groove extending along a straight-line trajectory, the manufacturing is simple and convenient, thereby facilitating the reduction of manufacturing cost.

[0030] As an optional technical solution of the embodiment of the present application, the groove width of the groove segment gradually increases from one end of the groove segment close to the electrode terminal to one end of the groove segment away from the electrode terminal.

[0031] In the above technical solution, by making the groove width of the groove segment gradually increase from one end of the groove segment close to the electrode terminal to one end of the groove segment away from the electrode terminal, it is beneficial to reduce the resistance of the first wall portion tearing along the extension direction of the groove segment, and a larger opening can be quickly opened when the cylindrical battery monomer is depressurized, thereby facilitating the rapid depressurization of the cylindrical battery monomer and improving the timeliness of the depressurization of the cylindrical battery monomer.

[0032] As an optional technical solution of the embodiment of the present application, in the radial direction of the cylindrical battery monomer, the groove segment includes a first end away from the electrode terminal, the first ends of a plurality of groove segments are located on a first circular line, the area of the region defined by the first circular line is S3, and in the axial direction of the cylindrical battery monomer, the area of the orthographic projection of the first wall portion is S2, and it is satisfied that 10%≤S3 / S2≤90%.

[0033] In the technical solution, when S3 / S2≥10%, the area of the region defined by the first circular line is larger, so that the region defined by the first circular line is easily affected by the discharge inside the cylindrical battery cell, thereby opening in time when the cylindrical battery cell is depressurized, which is conducive to improving the timeliness of the cylindrical battery cell depressurization. When S3 / S2≤90%, the area of the region defined by the first circular line is not too large, which can reduce the risk of the weak section cracking due to the change of the internal gas pressure of the cylindrical battery cell, and is conducive to improving the reliability of the cylindrical battery cell. Therefore, when 10%≤S3 / S2≤90%, the timeliness and reliability of the battery cell depressurization can be considered.

[0034] As an optional technical solution of the embodiment of the application, 20%≤S3 / S2≤55%.

[0035] In the technical solution, when S3 / S2≥20%, the area of the region defined by the first circular line is larger, so that the region defined by the first circular line is more easily affected by the discharge inside the cylindrical battery cell, thereby opening in time when the cylindrical battery cell is depressurized, which is more conducive to improving the timeliness of the cylindrical battery cell depressurization. When S3 / S2≤55%, the area of the region defined by the first circular line is not too large, which can reduce the risk of the weak section cracking due to the change of the internal gas pressure of the cylindrical battery cell, and is conducive to improving the reliability of the cylindrical battery cell. Therefore, when 20%≤S3 / S2≤55%, the timeliness and reliability of the battery cell depressurization can be considered.

[0036] As an optional technical solution of the embodiment of the application, the first wall portion is provided with a lead-out hole, the electrode terminal is at least partially arranged in the lead-out hole, and a plurality of groove segments are arranged around the lead-out hole. Along the radial direction of the cylindrical battery cell, the minimum distance between the groove segment and the lead-out hole is L, which satisfies: 1mm≤L≤4mm.

[0037] In the technical solution, when L≤4mm, the minimum distance between the groove segment and the lead-out hole along the radial direction of the cylindrical battery monomer is small, so that the area near the lead-out hole is relatively weak. Thus, the first wall portion is prone to crack at the position of the lead-out hole when the cylindrical battery monomer is depressurized, and then the first wall portion can tear along the extension direction of the groove segment, thereby opening a larger opening to facilitate the discharge of the discharge material in the cylindrical battery monomer to the outside. In this process, the electrode terminal can not only be displaced under the action of the first wall portion, but also be moved outward under the action of the discharge material, so that the connection position of the electrode terminal and the tab is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal and the tab, inhibiting the further development of thermal runaway, and improving the reliability of the cylindrical battery monomer. When L≥1mm, the minimum distance between the groove segment and the lead-out hole along the radial direction of the cylindrical battery monomer is not too small, which can reduce the risk of cracking of the weak section due to the change of the internal gas pressure of the cylindrical battery monomer, thereby improving the reliability of the cylindrical battery monomer. Therefore, when 1mm≤L≤4mm, the cylindrical battery monomer has high reliability.

[0038] As an optional technical solution of the embodiment, the first wall portion is provided with a lead-out hole, and the electrode terminal is at least partially arranged in the lead-out hole. The area surrounded by the orthographic projection of the hole wall surface of the lead-out hole along the axial direction of the cylindrical battery monomer is S4, and the area of the orthographic projection of the first wall portion is S2, and 15%≤S4 / S2≤85% is satisfied.

[0039] In the technical solution, when S4 / S2≥15%, the area surrounded by the orthographic projection of the hole wall surface of the lead-out hole along the axial direction of the cylindrical battery monomer is large, and the lead-out hole is large, so that the strength of the first wall portion is low. Thus, when the cylindrical battery monomer is depressurized, the first wall portion is prone to at least partially open, thereby driving the electrode terminal to displace, so that the connection position of the electrode terminal and the tab is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal and the tab, inhibiting the further development of thermal runaway, and improving the reliability of the cylindrical battery monomer. When S4 / S2≤85%, the area surrounded by the orthographic projection of the hole wall surface of the lead-out hole along the axial direction of the cylindrical battery monomer is not too large, and the lead-out hole is not too large, so that the first wall portion has sufficient strength to resist the impact of the outside, thereby protecting the electrode assembly and reducing the risk of cracking of the first wall portion due to the change of the internal gas pressure of the cylindrical battery monomer, thereby improving the reliability of the cylindrical battery monomer. Therefore, when 15%≤S4 / S2≤85%, the cylindrical battery monomer has high reliability.

[0040] As an optional technical solution of the embodiment, 25%≤S4 / S2≤55% is satisfied.

[0041] In the technical scheme, when S4 / S2≥25%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole along the axial direction of the cylindrical battery monomer is larger, the lead-out hole is larger, and the strength of the first wall part is lower. Thus, when the cylindrical battery monomer is depressurized, the first wall part is more likely to be at least partially opened, thereby driving the electrode terminal to be displaced, and the connection position of the electrode terminal and the tab is at least partially damaged, the overcurrent capacity between the electrode terminal and the tab is reduced, and the further development of thermal runaway is inhibited, thereby improving the reliability of the cylindrical battery monomer. When S4 / S2≤55%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole along the axial direction of the cylindrical battery monomer is not too large, the lead-out hole is not too large, and the first wall part has sufficient strength to resist external impact, thereby protecting the electrode assembly and reducing the risk of the first wall part being cracked due to the change in the internal gas pressure of the cylindrical battery monomer, thereby improving the reliability of the cylindrical battery monomer. Therefore, when 25%≤S4 / S2≤55%, the cylindrical battery monomer has higher reliability.

[0042] As an optional technical scheme of the embodiment, the thickness of the weak part is H1, the thickness of the first wall part is H2, and 0.05≤H1 / H2≤0.9 is met.

[0043] In the technical scheme, when H1 / H2≥0.05, the thickness of the weak part is larger, and the risk of the weak part being cracked due to the change in the internal gas pressure of the cylindrical battery monomer is reduced, thereby improving the reliability of the cylindrical battery monomer. When H1 / H2≤0.9, the thickness of the weak part is not too large, thereby facilitating the timely cracking of the weak part when the cylindrical battery monomer is depressurized, and improving the timeliness of the depressurization of the cylindrical battery monomer. Therefore, when 0.05≤H1 / H2≤0.9, the thickness of the weak part is moderate, the weak part is neither easily cracked due to the change in the internal gas pressure of the cylindrical battery monomer nor timely cracked when the cylindrical battery monomer is depressurized, and the timeliness of the depressurization of the cylindrical battery monomer is improved.

[0044] As an optional technical scheme of the embodiment, 0.35≤H1 / H2≤0.65 is met.

[0045] In the technical solution, when H1 / H2 is greater than or equal to 0.35, the thickness of the weak part is greater, and the risk of the weak part cracking due to the change of the internal gas pressure of the cylindrical battery cell is reduced, thereby improving the reliability of the cylindrical battery cell. When H1 / H2 is less than or equal to 0.65, the thickness of the weak part is not too large, thereby facilitating the timely cracking of the weak part when the cylindrical battery cell is depressurized, and improving the timeliness of the cylindrical battery cell. Therefore, when 0.35≤H1 / H2≤0.65, the thickness of the weak part is moderate, the weak part is neither prone to cracking due to the change of the internal gas pressure of the cylindrical battery cell nor timely cracking when the cylindrical battery cell is depressurized, thereby improving the timeliness of the cylindrical battery cell.

[0046] As an optional technical solution of the embodiment, the first wall part is provided with a first groove, and the first wall part forms the weak part at a region where the first groove is arranged.

[0047] In the technical solution, the weak part is formed on the wall part by arranging the first groove on the first wall part, and the first wall part cracks along at least a part of the first groove when the battery cell is depressurized, which is simple, convenient and low in cost.

[0048] As an optional technical solution of the embodiment, the first groove is arranged on a surface of the first wall part facing the inside of the shell, and / or the first groove is arranged on a surface of the first wall part away from the inside of the shell.

[0049] In the technical solution, when the first groove is arranged on the surface of the first wall part facing the inside of the shell, the first groove faces the inside of the battery cell, and the first groove is not exposed to the outside of the cylindrical battery cell, thereby reducing the risk of the position of the first wall part where the first groove is arranged being oxidized due to being exposed to the outside of the cylindrical battery cell. When the first groove is arranged on the surface of the first wall part away from the inside of the shell, the manufacturing is simple, convenient and low in cost.

[0050] As an optional technical solution of the embodiment, the shell comprises a shell body and an end cover, the shell body comprises an integrally formed bottom wall and a side wall, one end of the side wall is arranged around the bottom wall, and the other end of the side wall is arranged to form an opening; the end cover closes the opening; and the bottom wall is the first wall part.

[0051] In the technical solution, the bottom wall is the first wall part, and the electrode terminal is arranged on the bottom wall, which is convenient for installing the electrode terminal and facilitates the accurate installation of the electrode terminal and the stability of the connection between the electrode terminal and the electrode assembly. In addition, the bottom wall is provided with the weak part, so that the cylindrical battery cell can be depressurized from the side where the bottom wall is arranged, and the heat management component can be arranged on the side where the end cover is arranged to manage the temperature of the cylindrical battery cell.

[0052] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned cylindrical battery cell.

[0053] Thirdly, embodiments of this application also provide an electrical device, the electrical device including the above-mentioned cylindrical battery cell, the cylindrical battery cell being used to provide electrical energy to the electrical device. Attached Figure Description

[0054] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0056] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0057] Figure 3 This is a schematic diagram of the structure of a cylindrical battery cell provided in some embodiments of this application;

[0058] Figure 4 Exploded views of cylindrical battery cells provided in some embodiments of this application;

[0059] Figure 5 Schematic diagrams of the housing structure provided for some embodiments of this application;

[0060] Figure 6 A top view of the housing provided for some embodiments of this application;

[0061] Figure 7 for Figure 6 A cross-sectional view at position AA in the middle;

[0062] Figure 8 Schematic diagrams of the housing structure provided for other embodiments of this application;

[0063] Figure 9 Top view schematic diagram of the housing provided for other embodiments of this application;

[0064] Figure 10 for Figure 9 A cross-sectional view at position BB in the middle;

[0065] Figure 11 A top view of the housing provided for some embodiments of this application;

[0066] Figure 12 for Figure 11 a cross-sectional view along the line C-C;

[0067] Figure 13 a top view of a housing provided for further embodiments of the present application;

[0068] Figure 14 for Figure 13 a cross-sectional view along the line D-D;

[0069] Figure 15 a top view of a housing provided for further embodiments of the present application.

[0070] Fig. 10: box; 11: first box body; 12: second box body; 20: cylindrical battery cell; 21: outer shell; 211: housing; 2111: side wall; 2112: bottom wall; 212: end cover; 213: first wall portion; 22: electrode assembly; 221: main body; 222: tab; 23: electrode terminal; 231: lead-out hole; 241: weak portion; 2411: weak section; 242: first groove; 2421: groove section; 24211: first end; 243: first circular line; 25: current collecting member; 100: battery device; 200: controller; 300: motor; 1000: vehicle. DETAILED DESCRIPTION

[0071] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, any other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0072] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as those commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, and are not used to describe a particular order or primary and secondary relationship.

[0073] The term "embodiment" is mentioned in the present application means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0074] In the description of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; for those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0075] The term "and / or" in the present application is only to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. In addition, the character " / " in the present application generally represents that the front and rear associated objects have an "or" relationship.

[0076] In the embodiments of the present application, the same reference signs represent the same parts, and for the sake of brevity, the detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length and width of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0077] "Multiple" appearing in the present application means two or more (including two).

[0078] In the embodiments of the present application, the cylindrical battery cell can be a secondary battery, which refers to a cylindrical battery cell that can be activated by charging after discharging to continue using the active material.

[0079] The cylindrical battery cell includes but is not limited to lithium ion battery, sodium ion battery, sodium lithium ion battery, lithium metal battery, sodium metal battery, lithium sulfur battery, magnesium ion battery, nickel hydrogen battery, nickel cadmium battery, lead-acid battery, etc.

[0080] The cylindrical battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode and a separator. During the charging and discharging process of the cylindrical battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, which can reduce the risk of short circuit of the positive and negative electrodes, and at the same time allow the active ions to pass through.

[0081] In some embodiments, the positive electrode can be a positive electrode tab, which can include a positive electrode current collector and a positive electrode active material arranged on at least one surface of the positive electrode current collector.

[0082] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode active material is provided on either one or both of the two surfaces of the positive electrode current collector.

[0083] As an example, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, aluminum subjected to silver plating on the surface, stainless steel subjected to silver plating on the surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be employed. The composite current collector can include a high molecular material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a high molecular material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0084] As an example, the positive electrode active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each of them. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or two or more of them can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to simply as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, lithium cobalt oxide (such as LiCo02), lithium nickel oxide (such as LiNi02), lithium manganese oxide (such as LiMn02, LiMn204), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to simply as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to simply as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to simply as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to simply as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1O2(also can be referred to as NCM 811 LiNi 0.85 Co 0.15 Al 0.05 O2) and modified compounds thereof.

[0085] In some embodiments, the positive electrode can employ a foam metal. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, etc. When the foam metal is used as the positive electrode, the foam metal surface can not be provided with the positive electrode active material, or of course can be provided with the positive electrode active material. As an example, the foam metal can also be filled or / and deposited with a lithium source material, a potassium metal or a sodium metal, the lithium source material being a lithium metal and / or a lithium-rich material.

[0086] In some embodiments, the negative electrode can be a negative electrode tab, which can include a negative electrode current collector.

[0087] As an example, the negative electrode current collector can employ a metal foil, a foam metal or a composite current collector. For example, as the metal foil, silver surface treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel or titanium, etc. can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0088] As an example, the negative electrode tab can include the negative electrode current collector and the negative electrode active material provided on at least one surface of the negative electrode current collector.

[0089] As an example, the negative electrode current collector has two opposite surfaces in the thickness direction thereof, and the negative electrode active material is provided on either one or both of the two opposite surfaces of the negative electrode current collector.

[0090] As an example, the negative electrode active material can employ a negative electrode active material known in the art for a cylindrical battery cell. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative electrode active material can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0091] In some embodiments, the material of the positive current collector can be aluminum, and the material of the negative current collector can be copper.

[0092] In some embodiments, the separator is a separator film. The separator film can be any porous structure separator film known to have good chemical stability and mechanical stability.

[0093] As an example, the material of the separator film can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film. When the separator film is a multi-layer composite film, the material of each layer can be the same or different. The separator can be a separate component between the positive and negative electrodes, or can be attached to the surface of the positive and negative electrodes.

[0094] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive and negative electrodes, and functions to transport ions and separate the positive and negative electrodes.

[0095] In some embodiments, the cylindrical battery cell further includes an electrolyte, which functions to conduct ions between the positive and negative electrodes. The electrolyte can be in a liquid state, a gel state, or a solid state. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0096] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium boric oxalate, lithium difluoroboric dioxalate, and lithium tetrafluorophosphoric oxalate.

[0097] In some embodiments, the solvent can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butanedisulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0098] Among them, the gel-state electrolyte includes a polymer as a skeleton network of the electrolyte, and an ionic liquid-lithium salt.

[0099] Among them, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0100] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, a cellulose, or the like.

[0101] As an example, the inorganic solid-state electrolyte can include one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0102] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0103] In some embodiments, the electrode assembly is in a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound into the jelly-roll structure.

[0104] In some embodiments, the electrode assembly is in a stack structure.

[0105] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be alternately stacked.

[0106] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet is folded to form a plurality of folded segments that are stacked.

[0107] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded segments that are stacked.

[0108] As an example, a plurality of separators can be provided, and each of the separators is provided between any adjacent positive electrode sheet or negative electrode sheet.

[0109] As an example, the separators can be continuously provided and provided between any adjacent positive electrode sheet or negative electrode sheet by folding or winding.

[0110] In some embodiments, the electrode assembly can have a cylindrical shape, a flat shape, or a multi-prism shape, or the like.

[0111] In some embodiments, the electrode assembly is provided with a tab. The tab can guide current out of the electrode assembly. The tab includes a positive electrode tab and a negative electrode tab.

[0112] In some embodiments, the cylindrical battery cell can include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, or the like.

[0113] The battery apparatus mentioned in the embodiments of the present application can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of cylindrical battery cells connected in series, in parallel, or in a mixed connection through a busbar component.

[0114] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of cylindrical battery cells; as an example, the battery cell assembly can be a battery module formed by arranging and fixing a plurality of cylindrical battery cells into an independent module.

[0115] As an example, the battery module can be formed by bundling a plurality of cylindrical battery cells with a cable tie.

[0116] In some embodiments, the battery apparatus can be a battery pack, which can include a box and one or more battery cell assemblies accommodated in the box.

[0117] As an example, the battery cell assembly can be a battery module, which can be accommodated in the box by fixing the battery module in the box.

[0118] As an example, the battery cell assembly can also be accommodated in the box by directly fixing a plurality of cylindrical battery cells in the box.

[0119] As an example, the box can include a first box body and a second box body. The first box body and the second box body are buckled so that a closed space is formed inside the box to accommodate the battery cell assembly. Here, closed means covered or closed, which can be sealed or unsealed. The first box body can be a top cover or a bottom plate.

[0120] As an example, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected with the frame, so that a closed space is formed inside the box to accommodate the battery cell assembly.

[0121] As an example, the box can be part of the chassis structure of a vehicle. For example, the top cover of the box can be at least part of the floor of the vehicle, or the frame of the box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0122] In some embodiments, the battery apparatus refers to an energy storage device, which includes a box, at least one side of which is provided with a door. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0123] At present, from the development of market situation, the application of battery is more and more extensive. The battery is not only applied to the energy storage power system of hydropower, thermal power, wind power and solar power station, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment and aerospace and other fields. With the continuous expansion of the application field of battery, the demand of its market is also increasing.

[0124] The development of battery technology needs to consider many design factors, such as battery life, energy density, discharge capacity, charge-discharge rate and other performance parameters. In addition, the reliability of the battery also needs to be considered. However, the reliability of the current battery is poor.

[0125] In some embodiments, in order to improve the reliability of the cylindrical battery cell, a pressure relief mechanism can be generally provided on the shell of the cylindrical battery cell. When the cylindrical battery cell is in thermal runaway, the pressure inside the cylindrical battery cell can be released through the pressure relief mechanism.

[0126] The pressure relief mechanism refers to an element or component that is actuated to release the internal pressure when the internal pressure of the cylindrical battery cell reaches a predetermined threshold. The threshold value is designed according to different design requirements. The threshold value may depend on the material of one or more of the positive electrode plate, the negative electrode plate, the electrolyte and the separator in the cylindrical battery cell.

[0127] The "actuation" mentioned in the present application refers to the action or activation of the pressure relief mechanism to a certain state, so that the internal pressure of the cylindrical battery cell can be released. The action of the pressure relief mechanism can include but is not limited to: at least part of the pressure relief mechanism is broken, broken, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances inside the cylindrical battery cell will be discharged outward from the actuated part as the discharge. In this way, the cylindrical battery cell can be relieved under controllable pressure, thereby avoiding potential more serious accidents.

[0128] The discharge from the cylindrical battery cell mentioned in the embodiments of the present application includes but is not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separator film, high-temperature and high-pressure gas generated by reaction, flame, etc.

[0129] The cylindrical battery cell includes an electrode terminal, which is provided on the shell and is used to electrically connect with the electrode assembly to output or input the electrical energy of the cylindrical battery cell through the electrode terminal. In the prior art, when the pressure relief mechanism is actuated, the electrode terminal still maintains the electrical connection state with the electrode assembly, and the cylindrical battery cell is in a pass-through state, so that the cylindrical battery cell still continues to generate heat when it is in thermal runaway, which further develops the thermal runaway, resulting in poor reliability of the cylindrical battery cell.

[0130] To solve the problem of poor reliability of the cylindrical battery cell, the embodiment of the present application provides a cylindrical battery cell. The cylindrical battery cell comprises a shell, an electrode assembly and an electrode terminal. The shell has a first wall portion. The electrode assembly is at least partially accommodated in the shell, and the electrode assembly comprises a tab. The electrode terminal is arranged on the first wall portion, and the electrode terminal is electrically connected with the tab. The first wall portion has a weak portion configured to be damaged when the cylindrical battery cell is depressurized, so that at least part of the first wall portion is opened, and the first wall portion can drive the electrode terminal to move in a direction away from the tab when the first wall portion is opened, so that the connection position of the electrode terminal and the tab is at least partially damaged.

[0131] The first wall portion of the cylindrical battery cell can be at least partially split along the weak portion when the cylindrical battery cell is depressurized, so that the first wall portion is at least partially opened, thereby facilitating the discharge of the discharge material in the cylindrical battery cell to the outside, and achieving depressurization. In this process, the electrode terminal is displaced under the driving of the first wall portion, so that the connection position of the electrode terminal and the tab is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal and the tab, and thereby facilitating the suppression of further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell.

[0132] The cylindrical battery cell described in the embodiment of the present application is suitable for a battery device and an electric device using the cylindrical battery cell.

[0133] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game machine, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc.

[0134] The following embodiments are described by taking the electric device as a vehicle for convenience of description.

[0135] Please refer to Figure 1 , Figure 1 The structure schematic diagram of the vehicle 1000 provided by some embodiments of the present application is shown. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as the operating power supply of the vehicle 1000.

[0136] The vehicle 1000 can further include a controller 200 and a motor 300, the controller 200 being configured to control the battery device 100 to supply power to the motor 300, for example, for power requirements of the vehicle 1000 during start-up, navigation, and travel.

[0137] In some embodiments of the present application, the battery device 100 can not only serve as a power source for the operation of the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0138] Please refer to Figure 2 , Figure 2 An exploded view of the battery device 100 is provided for some embodiments of the present application. The battery device 100 can include a box body 10 and cylindrical battery cells 20, the box body 10 being configured to accommodate the cylindrical battery cells 20.

[0139] The box body 10 has an enclosed space formed inside for accommodating the cylindrical battery cells 20. The box body 10 can have various structures. In some embodiments, the box body 10 can include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 being coupled to each other. The first box body 11 and the second box body 12 can have various shapes, such as a cuboid, a cylinder, etc. The first box body 11 can be a hollow structure with one side open, and the second box body 12 can also be a hollow structure with one side open. The open side of the second box body 12 and the open side of the first box body 11 are coupled to each other, thereby forming the box body 10 with an enclosed space. Alternatively, the first box body 11 can be a hollow structure with one side open, and the second box body 12 can be a plate-shaped structure, the second box body 12 being coupled to the open side of the first box body 11, thereby forming the box body 10 with an enclosed space.

[0140] In the battery device 100, the cylindrical battery cells 20 can be one or multiple. If the cylindrical battery cells 20 are multiple, the multiple cylindrical battery cells 20 can be connected in series, in parallel, or in a mixed connection, the mixed connection referring to a connection in which the multiple cylindrical battery cells 20 are connected in series and in parallel. The multiple cylindrical battery cells 20 can be connected in series, in parallel, or in a mixed connection to form a battery module, and the multiple battery modules can be connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the box body 10. Alternatively, all the cylindrical battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and the whole formed by the cylindrical battery cells 20 is accommodated in the box body 10.

[0141] In some embodiments, the battery device 100 can further include a current collecting component, and the multiple cylindrical battery cells 20 can be electrically connected through the current collecting component to achieve a series connection, a parallel connection, or a mixed connection of the multiple cylindrical battery cells 20. The current collecting component can be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0142] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , Figure 3 A schematic view of a cylindrical battery cell 20 according to some embodiments of the present application. Figure 4 An exploded view of a cylindrical battery cell 20 according to some embodiments of the present application. Figure 5 A schematic view of a housing 211 according to some embodiments of the present application. Figure 6 A top view of a housing 211 according to some embodiments of the present application. Figure 7 A cross-sectional view of position A-A in Figure 6 A cylindrical battery cell 20 according to some embodiments of the present application includes a housing 21 having a first wall portion 213, an electrode assembly 22 at least partially housed in the housing 21, and an electrode terminal 23 disposed on the first wall portion 213 and electrically connected to the electrode assembly 22. The first wall portion 213 has a weakened portion 241 configured to be broken when the cylindrical battery cell 20 is depressurized, so that at least a portion of the first wall portion 213 is opened, and the first wall portion 213, when opened, is capable of moving the electrode terminal 23 in a direction away from the electrode assembly 22, so that the connection between the electrode terminal 23 and the electrode assembly 22 is at least partially broken.

[0143] A cylindrical battery cell 20 refers to the smallest unit that constitutes a battery device 100.

[0144] The housing 21 includes a housing 211 having an open-ended receiving space for receiving the electrode assembly 22, and an end cap 212 connected to the housing 211 and closing the opening.

[0145] The end cap 212 refers to a component that covers the opening of the housing 211 to isolate the internal environment of the cylindrical battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the housing 211 to fit the housing 211. Alternatively, the end cap 212 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cap 212 is less likely to deform when subjected to extrusion and impact, allowing the cylindrical battery cell 20 to have higher structural strength and improved reliability. The material of the end cap 212 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0146] The shell 211 is a component for cooperating with the end cover 212 to form an internal environment of the cylindrical battery cell 20, and the formed internal environment can be used to accommodate the electrode assembly 22, the electrolyte, and other components. The shell 211 and the end cover 212 can be independent components, and an opening can be provided on the shell 211, and the end cover 212 is used to cover the opening to form the internal environment of the cylindrical battery cell 20. Without limitation, the end cover 212 and the shell 211 can also be integrated, specifically, the end cover 212 and the shell 211 can form a common joint surface before other components enter the shell, and when it is necessary to seal the internal environment of the shell 211, the end cover 212 is used to cover the shell 211. The shell 211 can be various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, and the like. Specifically, the shape of the shell 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the shell 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, and the like.

[0147] The electrode assembly 22 is a component in which electrochemical reactions occur in the cylindrical battery cell 20. One or more electrode assemblies 22 can be contained in the shell 211. The electrode assembly 22 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and an isolation film is usually provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet have a portion with active material constituting a main body 221 of the electrode assembly 22, and a portion without active material constituting a tab 222 of the positive electrode sheet and the negative electrode sheet, respectively. The positive electrode tab and the negative electrode tab can be located together at one end of the main body 221 or at two ends of the main body 221, respectively. During the charging and discharging process of the cylindrical battery cell 20, the positive active material and the negative active material react with the electrolyte.

[0148] The first wall portion 213 can be the end cover 212 of the shell 21, or a wall portion of the shell 211 of the shell 21. Exemplarily, in Figure 3 and Figure 4 , the first wall portion 213 is a bottom wall 2112 of the shell 211 opposite to the end cover 212. In other embodiments, the first wall portion 213 is the end cover 212.

[0149] The electrode terminal 23 is used to electrically connect with the tab 222 of the electrode assembly 22 to input or output the electrical energy of the cylindrical battery cell 20. The electrode terminal 23 can be directly connected with the tab 222, such as directly welded with the tab 222. The electrode terminal 23 can also be indirectly connected with the tab 222, such as indirectly connected with the tab 222 through the current collecting member 25.

[0150] As an example, in Figure 3 and Figure 4In the shown embodiment, the housing 211 is formed with an opening at one end only, and the end cover 212 is one, which closes the opening of the housing 211, and the electrode terminal 23 is arranged on the wall opposite to the end cover 212. The electrode assembly 22 is formed with the tab 222 at both opposite ends, the tab 222 at one end of the electrode assembly 22 is the positive tab, and the tab 222 at the other end of the electrode assembly 22 is the negative tab, and the electrode terminal 23 is electrically connected to the positive tab through one current collecting member 25, and the end cover 212 is electrically connected to the negative tab through another current collecting member 25.

[0151] The first wall 213 has a weak portion 241, which functions as a pressure relief, for enabling the first wall 213 to crack along the weak portion 241 to release the pressure inside the cylindrical battery cell 20 when the internal pressure or temperature of the cylindrical battery cell 20 reaches a predetermined threshold. In some embodiments, the strength of the first wall 213 at the position of the weak portion 241 can be lower than that of the first wall 213 at other positions, so that the weak portion 241 can crack under the internal pressure when the internal pressure or temperature of the cylindrical battery cell 20 reaches the predetermined threshold to release the pressure inside the cylindrical battery cell 20. In other embodiments, the melting point of the first wall 213 at the position of the weak portion 241 can be lower than that of the first wall 213 at other positions. In this way, the weak portion 241 can crack under high temperature when the internal pressure or temperature of the cylindrical battery cell 20 reaches the predetermined threshold to release the pressure inside the cylindrical battery cell 20.

[0152] When the first wall 213 cracks along at least a portion of the weak portion 241, the first wall 213 is at least partially opened, and the first wall 213 will be partially deformed or partially separated, thereby pulling the electrode terminal 23 and causing the electrode terminal 23 to displace, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially damaged, and the overcurrent capacity between the electrode terminal 23 and the tab 222 is reduced. The "partial deformation" means that the portion of the first wall 213 is deformed, but the deformed portion does not separate from the first wall 213. The "partial separation" means that the first wall 213 is separated into at least two portions, and the two portions are separated from each other and no longer have a connection relationship.

[0153] In the embodiment in which the electrode terminal 23 is welded to the tab 222, the “the connection position of the electrode terminal 23 and the tab 222 is at least partially destroyed” means that the weld connecting the electrode terminal 23 and the tab 222 is partially or entirely destroyed. When the weld connecting the electrode terminal 23 and the tab 222 is partially destroyed, the electrode terminal 23 and the tab 222 are still in a conduction state, but the overcurrent capacity between the electrode terminal 23 and the tab 222 is reduced, thus reducing the current output by the cylindrical battery cell 20, which is conducive to inhibiting further development of thermal runaway. When the weld connecting the electrode terminal 23 and the tab 222 is entirely destroyed, the electrode terminal 23 and the tab 222 are in an open circuit state, and the cylindrical battery cell 20 no longer outputs current, which is conducive to inhibiting further development of thermal runaway.

[0154] In the embodiment in which the electrode terminal 23 is indirectly connected to the tab 222 through the current collecting member 25, the “the connection position of the electrode terminal 23 and the tab 222 is at least partially destroyed” means that the weld connecting the electrode terminal 23 and the current collecting member 25 and / or the weld connecting the current collecting member 25 and the tab 222 is partially or entirely destroyed. When the weld connecting the electrode terminal 23 and the current collecting member 25 and / or the weld connecting the current collecting member 25 and the tab 222 is partially destroyed, the electrode terminal 23 and the tab 222 are still in a conduction state, but the overcurrent capacity between the electrode terminal 23 and the tab 222 is reduced, thus reducing the current output by the cylindrical battery cell 20, which is conducive to inhibiting further development of thermal runaway. When the weld connecting the electrode terminal 23 and the current collecting member 25 and / or the weld connecting the current collecting member 25 and the tab 222 is entirely destroyed, the electrode terminal 23 and the tab 222 are in an open circuit state, and the cylindrical battery cell 20 no longer outputs current, which is conducive to inhibiting further development of thermal runaway.

[0155] The first wall portion 213 of the cylindrical battery cell 20 can be broken along at least part of the weak portion 241, partially deformed or partially detached when the cylindrical battery cell 20 is depressurized, thus facilitating the discharge of the discharge material in the cylindrical battery cell 20 to the outside, achieving pressure relief. In this process, the electrode terminal 23 is displaced under the action of the first wall portion 213, causing the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, causing the cylindrical battery cell 20 to be in an open circuit state when depressurized, thus inhibiting further development of thermal runaway and improving the reliability of the cylindrical battery cell 20.

[0156] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the first wall portion 213 can cause the electrode terminal 23 and the tab 222 to be in an open circuit state when opened.

[0157] The weak portion 241 is configured to be broken when the cylindrical battery cell 20 is depressurized, to open at least part of the first wall portion 213, and the first wall portion 213, when opened, is configured to move the electrode terminal 23 in a direction away from the tab 222, to break the connection between the electrode terminal 23 and the tab 222.

[0158] In the embodiment in which the electrode terminal 23 is welded to the tab 222, “the connection between the electrode terminal 23 and the tab 222 is broken” means that the weld connecting the electrode terminal 23 and the tab 222 is broken. When the weld connecting the electrode terminal 23 and the tab 222 is broken, the electrode terminal 23 and the tab 222 are in an open circuit state, and the cylindrical battery cell 20 no longer outputs current, which is conducive to inhibiting further development of thermal runaway.

[0159] In the embodiment in which the electrode terminal 23 is indirectly connected to the tab 222 via the current collector 25, “the connection between the electrode terminal 23 and the tab 222 is broken” means that the weld connecting the electrode terminal 23 and the current collector 25 and / or the weld connecting the current collector 25 and the tab 222 is broken. When the weld connecting the electrode terminal 23 and the current collector 25 and / or the weld connecting the current collector 25 and the tab 222 is broken, the electrode terminal 23 and the tab 222 are in an open circuit state, and the cylindrical battery cell 20 no longer outputs current, which is conducive to inhibiting further development of thermal runaway.

[0160] The first wall portion 213 is configured to be at least partially opened when the cylindrical battery cell 20 is depressurized, to move the electrode terminal 23 in a direction away from the tab 222, to break the electrical connection between the electrode terminal 23 and the tab 222, and to open a circuit between the electrode terminal 23 and the tab 222, which is more conducive to inhibiting further development of thermal runaway and to improving the reliability of the cylindrical battery cell 20.

[0161] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the weak portion 241 is disposed around the electrode terminal 23.

[0162] The weak portion 241 can be a closed structure extending along a closed trajectory. The closed structure is disposed around the outside of the electrode terminal 23. For example, the weak portion 241 can be a ring structure, and the weak portion 241 is disposed around the outside of the electrode terminal 23.

[0163] The weak portion 241 can also be a non-closed structure extending along a non-closed trajectory having a gap at both ends. For example, the weak portion 241 can be a C-shaped structure or a U-shaped structure, and the weak portion 241 is disposed around the outside of the electrode terminal 23.

[0164] The weakened portion 241 can further include a plurality of weakened segments 2411, which are arranged at intervals along the circumference of the cylindrical battery cell 20 and surround the outside of the electrode terminal 23.

[0165] The weakened portion 241 is arranged around the electrode terminal 23, so that the first wall portion 213 is relatively weak in the region around the electrode terminal 23. Thus, when the cylindrical battery cell 20 is depressurized, the first wall portion 213 in the region around the electrode terminal 23 is more likely to locally deform or locally detach, thereby facilitating displacement of the electrode terminal 23, causing the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, causing the cylindrical battery cell 20 to be open-circuited when depressurized, thereby inhibiting further development of thermal runaway, and advantageously improving the reliability of the cylindrical battery cell 20.

[0166] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the first wall portion 213 has a pressure relief portion 244, the electrode terminal 23 is arranged in the pressure relief portion 244, and the weakened portion 241 is an annular structure arranged around the pressure relief portion 244 and the electrode terminal 23.

[0167] The pressure relief portion 244 is the part of the first wall portion 213 located in the region surrounded by the weakened portion 241. The region surrounded by the weakened portion 241 is the region in which the first wall portion 213 forms an opening after the weakened portion 241 is destroyed by the action of the discharge inside the housing 21. In the case where the weakened portion 241 is a closed structure extending along a closed trajectory, the region surrounded by the weakened portion 241 is the region inside the closed structure. In the case where the weakened portion 241 is a non-closed structure, the region surrounded by the weakened portion 241 is the region inside the closed structure formed by the weakened portion 241 itself and the connecting line between the two ends of the weakened portion 241.

[0168] The electrode terminal 23 is arranged in the pressure relief portion 244. When the cylindrical battery cell 20 is depressurized, the pressure relief portion 244 opens, and the electrode terminal 23 is driven by the pressure relief portion 244 to move away from the tab 222, so that the connection position between the electrode terminal 23 and the tab 222 is at least partially destroyed, reducing the overcurrent capacity between the electrode terminal 23 and the tab 222.

[0169] When the weakened portion 241 is an annular structure, the weakened portion 241 can be a closed structure extending along a closed trajectory. For example, the weakened portion 241 can be a circular ring structure, an elliptical ring structure, a racetrack-shaped structure, etc. The weakened portion 241 can also be a non-closed structure with a gap at both ends, for example, the weakened portion 241 can be a 180° circular arc structure, a 270° circular arc structure, etc.

[0170] When the weak portion 241 is in a ring structure, the first wall portion 213 is more likely to crack along the entire weak portion 241 when the cylindrical battery cell 20 is depressurized, so that the pressure relief portion 244 is more likely to flip open or detach from the first wall portion 213, thereby opening a larger opening for pressure relief, which is conducive to improving the timeliness of pressure relief of the cylindrical battery cell 20 and improving the reliability of the cylindrical battery cell 20. In addition, when the pressure relief portion 244 flips open or detaches from the first wall portion 213, the electrode terminal 23 is displaced to a greater extent, which is more likely to cause the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, thereby inhibiting further development of thermal runaway, which is conducive to improving the reliability of the cylindrical battery cell 20.

[0171] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 In some embodiments, the weak portion 241 is in a circular ring shape.

[0172] When the weak portion 241 is in a circular ring shape, the weak portion 241 is more uniformly stressed at different positions, and the first wall portion 213 is more likely to crack along the entire circumference of the weak portion 241 when the cylindrical battery cell 20 is depressurized, so that the pressure relief portion 244 is more likely to detach from the first wall portion 213, thereby opening a larger opening for pressure relief, which is conducive to improving the timeliness of pressure relief of the cylindrical battery cell 20 and improving the reliability of the cylindrical battery cell 20. In addition, when the pressure relief portion 244 detaches from the first wall portion 213, the electrode terminal 23 is displaced to a greater extent, which is more likely to cause the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, thereby inhibiting further development of thermal runaway, which is conducive to improving the reliability of the cylindrical battery cell 20.

[0173] In some embodiments, along the axial direction of the cylindrical battery cell 20, the area of the orthographic projection of the pressure relief portion 244 is S1, and the area of the orthographic projection of the first wall portion 213 is S2, which satisfies: 10%≤S1 / S2≤90%.

[0174] The axial direction of the cylindrical battery cell 20 refers to the extension direction of the central axis of rotation of the cylindrical battery cell 20. Please refer to Figure 3 and Figure 4 The axial direction of the cylindrical battery cell 20 is the X direction shown in the figure.

[0175] The first wall portion 213 is provided with a lead-out hole 231, and the electrode terminal 23 is at least partially disposed in the lead-out hole 231. The pressure relief portion 244 includes the area where the lead-out hole 231 is located.

[0176] S1 represents the area of the orthographic projection of the pressure relief portion 244 along the axial direction of the cylindrical battery cell 20, that is, the area enclosed by the orthographic projection of the weak portion 241 along the axial direction of the cylindrical battery cell 20.

[0177] S2 represents the area of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20. In the calculation, the radius of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 can be measured first, and then S2 can be calculated according to the radius of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20. Considering the case that the first wall portion 213 and the side wall 2111 have a fillet transition, the radius of the side wall 2111 can be taken as the radius of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20.

[0178] S1 / S2 represents the ratio of the area of the pressure relief portion 244 along the axial direction of the cylindrical battery monomer 20 to the area of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20.

[0179] The ratio of the area of the pressure relief portion 244 along the axial direction of the cylindrical battery monomer 20 to the area of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 can be: S1 / S2 = 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc.

[0180] When S1 / S2≥10%, the area of the pressure relief portion 244 along the axial direction of the cylindrical battery monomer 20 is large, so that the pressure relief portion 244 is easily affected by the discharge inside the cylindrical battery monomer 20, thereby opening in time when the cylindrical battery monomer 20 is relieved, which is beneficial to improve the timeliness of the cylindrical battery monomer 20. When S1 / S2≤90%, the area of the pressure relief portion 244 along the axial direction of the cylindrical battery monomer 20 is not too large, which can reduce the risk of the weak portion 241 being cracked due to the change of the gas pressure inside the cylindrical battery monomer 20, and is beneficial to improve the reliability of the cylindrical battery monomer 20. Therefore, when 10%≤S1 / S2≤90%, the timeliness and reliability of the battery monomer can be considered.

[0181] Optionally, 20%≤S1 / S2≤55%.

[0182] The ratio of the area of the pressure relief portion 244 along the axial direction of the cylindrical battery monomer 20 to the area of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 can be: S1 / S2 = 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.

[0183] When S1 / S2≥20%, the area of the normal projection of the pressure relief portion 244 along the axial direction of the cylindrical battery cell 20 is larger, so that the pressure relief portion 244 is more easily affected by the discharge inside the cylindrical battery cell 20, thereby opening in time when the cylindrical battery cell 20 is relieved, and is more conducive to improving the timeliness of the cylindrical battery cell 20. When S1 / S2≤55%, the area of the normal projection of the pressure relief portion 244 along the axial direction of the cylindrical battery cell 20 is not too large, which can reduce the risk of the weak portion 241 being cracked due to the change of the gas pressure inside the cylindrical battery cell 20, and is conducive to improving the reliability of the cylindrical battery cell 20. Therefore, when 20%≤S1 / S2≤55%, the timeliness and reliability of the battery cell can be better balanced.

[0184] Please refer to Figure 8 、 Figure 9 and Figure 10 , Figure 8 for the structural schematic diagram of the shell 211 provided by some embodiments of the present application. Figure 9 for the top view schematic diagram of the shell 211 provided by some embodiments of the present application. Figure 10 for Figure 9 the sectional view of the B-B position in FIG. 8. In some embodiments, the first wall portion 213 is provided with a plurality of weak portions 241, and the plurality of weak portions 241 are arranged along the radial direction of the cylindrical battery cell 20.

[0185] The radial direction of the cylindrical battery cell 20 refers to the direction along the radius of the cylindrical battery cell 20, and the radial direction of the cylindrical battery cell 20 is perpendicular to the axial direction of the cylindrical battery cell 20. Please refer to Figure 10 , the radial direction of the cylindrical battery cell 20 can be the Y direction shown in the figure.

[0186] The first wall portion 213 can be provided with two weak portions 241, three weak portions 241, four weak portions 241, or more than four weak portions 241. The plurality of weak portions 241 are sequentially arranged around the electrode terminal 23 along the radial direction of the cylindrical battery cell 20.

[0187] Please refer to Figure 8 、 Figure 9 and Figure 10 , in the embodiment shown in the figure, the first wall portion 213 is provided with two weak portions 241, both of which are circular rings, one weak portion 241 is arranged outside the electrode terminal 23, and the other weak portion 241 is arranged outside the above-mentioned one weak portion 241. Optionally, the axes of the two weak portions 241 overlap, and overlap with the axis of the electrode terminal 23.

[0188] By setting multiple weak portions 241, the multiple weak portions 241 are sequentially arranged around the electrode terminal 23 along the radial direction of the cylindrical battery cell 20. When the cylindrical battery cell 20 is depressurized, the first wall portion 213 is more likely to be at least partially opened, thereby driving the electrode terminal 23 to move away from the tab 222, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially damaged, reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell 20.

[0189] Please refer to Figure 11 and Figure 12 , Figure 11 The top view schematic diagram of the shell 211 provided in some embodiments of the present application is shown in FIG. 6. Figure 12 For Figure 11 The cross-sectional view of the C-C position in FIG. 5. In some embodiments, the weak portion 241 includes multiple weak segments 2411, and the multiple weak segments 2411 are arranged at intervals along the circumferential direction of the cylindrical battery cell 20.

[0190] The circumferential direction of the cylindrical battery cell 20 refers to the circumferential direction of the cylindrical battery cell 20. The circumferential direction of the cylindrical battery cell 20 is perpendicular to the radial direction of the cylindrical battery cell 20, and the circumferential direction of the cylindrical battery cell 20 is perpendicular to the axial direction of the cylindrical battery cell 20. Please refer to Figure 11 , the circumferential direction of the cylindrical battery cell 20 is the Z direction shown in the figure.

[0191] The weak portion 241 can include two weak segments 2411, three weak segments 2411, four weak segments 2411, or more weak segments 2411. Along the circumferential direction of the cylindrical battery cell 20, the multiple weak segments 2411 are arranged at intervals, and the distance between each adjacent two weak segments 2411 can be the same, in which case the multiple weak segments 2411 are arranged at equal intervals along the circumferential direction of the cylindrical battery cell 20. The distance between each adjacent two weak segments 2411 along the circumferential direction of the cylindrical battery cell 20 can also be different, in which case the multiple weak segments 2411 are arranged at unequal intervals along the circumferential direction of the cylindrical battery cell 20.

[0192] By arranging multiple weak sections 2411 along the circumference of the cylindrical battery cell 20, the first wall portion 213 can be broken along at least one weak section 2411 when the cylindrical battery cell 20 is depressurized, so that the first wall portion 213 is at least partially opened, thereby facilitating the discharge of the discharge material in the cylindrical battery cell 20 to the outside, achieving pressure relief. In this process, the electrode terminal 23 is displaced under the action of the first wall portion 213, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially destroyed, reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell 20. Along the circumference of the cylindrical battery cell 20, the part of the first wall portion 213 between the adjacent two weak sections 2411 has higher strength, which is conducive to reducing the risk of the weak portion 241 being broken due to the change of the internal gas pressure of the cylindrical battery cell 20, and is conducive to improving the reliability of the cylindrical battery cell 20.

[0193] Please refer to Figure 11 and Figure 12 In some embodiments, the first wall portion 213 is provided with a first groove 242, and the first groove 242 includes multiple groove sections 2421, and the multiple groove sections 2421 are arranged along the circumference of the cylindrical battery cell 20. The groove bottom wall 2112 of each groove section 2421 forms a weak section 2411.

[0194] Please refer to Figure 11 and 12 The thickness direction of the first wall portion 213 can be the X1 direction shown in the figure, and in the embodiment shown in the figure, the thickness direction of the first wall portion 213 is parallel to the axial direction of the cylindrical battery cell 20.

[0195] The first wall portion 213 has an inner surface and an outer surface arranged opposite to each other along the thickness direction thereof. The inner surface can be provided with the first groove 242, or the outer surface can be provided with the first groove 242.

[0196] The first groove 242 includes multiple groove sections 2421, and the multiple groove sections 2421 are arranged along the circumference of the cylindrical battery cell 20, and the groove sections 2421 are arranged one by one corresponding to the weak sections 2411. Taking the case that the inner surface is provided with the groove sections 2421, that is, the groove sections 2421 are recessed from the inner surface to the outer surface, the part between the groove bottom surface of each groove section 2421 and the outer surface forms a weak section 2411.

[0197] The first wall portion 213 is configured to be cracked along at least one of the groove segments 2421 and tear the portion of the first wall portion 213 between two adjacent groove segments 2421 when the cylindrical battery cell 20 is depressurized, so as to at least partially open the first wall portion 213, thereby facilitating the discharge of the dischargeable substance in the cylindrical battery cell 20 to the outside. This is simple and convenient, and has a low cost.

[0198] Please refer to Figure 11 and Figure 12 In some embodiments, the groove segments 2421 extend along the circumference of the cylindrical battery cell 20, and the first wall portion 213 is configured to be cracked along the groove segments 2421 and tear the portion of the first wall portion 213 between two adjacent groove segments 2421 when the cylindrical battery cell 20 is depressurized.

[0199] The “groove segments 2421 extend along the circumference of the cylindrical battery cell 20” means that the groove segments 2421 are arc-shaped grooves arranged around the axis of the cylindrical battery cell 20.

[0200] By extending the groove segments 2421 along the circumference of the cylindrical battery cell 20, the first wall portion 213 can be cracked along at least one of the groove segments 2421 and then tear the portion of the first wall portion 213 between two adjacent groove segments 2421 along the circumference of the cylindrical battery cell 20 when the cylindrical battery cell 20 is depressurized, so as to open a larger opening, thereby facilitating the discharge of the dischargeable substance in the cylindrical battery cell 20 to the outside. In this process, the electrode terminal 23 is displaced under the action of the first wall portion 213, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially destroyed, thereby reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell 20.

[0201] Please refer to Figure 13 and Figure 14 , Figure 13 A top view of the shell 211 according to some other embodiments of the present application is provided. Figure 14 As Figure 13 A sectional view of the D-D position in FIG. 11 is provided. In some other embodiments, the first wall portion 213 is provided with a lead-out hole 231, the electrode terminal 23 is at least partially arranged in the lead-out hole 231, and the groove segments 2421 are arranged around the lead-out hole 231. The groove segments 2421 extend along the radial direction of the cylindrical battery cell 20, and the first wall portion 213 is configured to be cracked from the lead-out hole 231 and torn along at least part of the groove segments 2421 when the cylindrical battery cell 20 is depressurized.

[0202] The first wall portion 213 is provided with a lead-out hole 231 that penetrates the first wall portion 213 in the thickness direction of the first wall portion 213. In other words, the lead-out hole 231 is a through hole provided in the first wall portion 213. The electrode terminal 23 can be partially or entirely disposed in the lead-out hole 231.

[0203] When the groove segment 2421 extends along the radial direction of the cylindrical battery cell 20, the groove segment 2421 can be a strip-shaped structure extending along the radial direction of the cylindrical battery cell 20, for example, the groove segment 2421 can be a straight groove, or the groove segment 2421 can be in the shape of a fan ring, in which case the axis of the groove segment 2421 can coincide with the axis of the cylindrical battery cell 20.

[0204] By extending the groove segment 2421 along the radial direction of the cylindrical battery cell 20, the first wall portion 213 can first crack from the position of the lead-out hole 231 where the electrode terminal 23 is provided when the cylindrical battery cell 20 is depressurized, and then the first wall portion 213 can tear along the extension direction of the groove segment 2421, thereby opening a larger opening to facilitate the discharge of the discharge material in the cylindrical battery cell 20 to the outside. In this process, the electrode terminal 23 not only can be displaced under the action of the first wall portion 213, but also can be moved outward under the action of the discharge material, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially destroyed, thereby reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell 20.

[0205] Please refer to Figure 13 and Figure 14 In some embodiments, the groove segment 2421 is an equal-width groove extending along a straight trajectory.

[0206] The "groove segment 2421 is an equal-width groove extending along a straight trajectory" means that the groove width of the groove segment 2421 is equal from one end of the groove segment 2421 close to the electrode terminal 23 to the other end of the groove segment 2421 away from the electrode terminal 23.

[0207] By setting the groove segment 2421 as an equal-width groove extending along a straight trajectory, it is simple and convenient to manufacture, thereby facilitating the reduction of manufacturing cost.

[0208] Please refer to Figure 15 , Figure 15 is a top view schematic diagram of the housing 211 provided by some embodiments of the present application. In some embodiments, the groove width of the groove segment 2421 gradually increases from one end of the groove segment 2421 close to the electrode terminal 23 to the other end of the groove segment 2421 away from the electrode terminal 23.

[0209] Along the radial direction of the cylindrical battery monomer 20, the groove segment 2421 includes a first end 24211 away from the electrode terminal 23 and a second end close to the electrode terminal 23, wherein the groove width of the first end 24211 is the largest, and the groove width of the second end is the smallest. The groove width of the groove segment 2421 gradually decreases from the first end 24211 to the second end.

[0210] Please refer to Figure 15 , in Figure 15 , the groove segment 2421 is a fan ring.

[0211] By gradually increasing the groove width of the groove segment 2421 from one end of the groove segment 2421 close to the electrode terminal 23 to the other end of the groove segment 2421 away from the electrode terminal 23, it is beneficial to reduce the resistance of the first wall portion 213 along the extension direction of the groove segment 2421. When the cylindrical battery monomer 20 is depressurized, a larger opening can be quickly opened, which facilitates the rapid depressurization of the cylindrical battery monomer 20, and is beneficial to improve the timeliness of the cylindrical battery monomer 20.

[0212] Please refer to Figure 15 , in some embodiments, along the radial direction of the cylindrical battery monomer 20, the groove segment 2421 includes a first end 24211 away from the electrode terminal 23, and the first ends 24211 of the plurality of groove segments 2421 are located on a first circular line 243. The area of the region defined by the first circular line 243 is S3, and the area of the orthographic projection of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 is S2, which satisfies: 10%≤S3 / S2≤90%.

[0213] The first circular line 243 is a virtual line in a circular shape. In order to facilitate the illustration, the first circular line 243 is shown by a dashed line in Figure 15 . The end of the plurality of groove segments 2421 away from the electrode terminal 23 is located on the first circular line 243.

[0214] S3 represents the area of the region defined by the first circular line 243. It should be noted that the first wall portion 213 is provided with a lead-out hole 231, and the electrode terminal 23 is at least partially arranged in the lead-out hole 231. The region defined by the first circular line 243 includes the region where the lead-out hole 231 is located.

[0215] S3 / S2 represents the ratio of the area of the region defined by the first circular line 243 to the area of the orthographic projection of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20.

[0216] The ratio of the area of the region defined by the first circular line 243 to the area of the orthographic projection of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 can be: S3 / S2=10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc.

[0217] When S3 / S2≥10%, the area of the region defined by the first circular line 243 is larger, so that the region defined by the first circular line 243 is more easily affected by the discharge inside the cylindrical battery cell 20, thereby opening in time when the cylindrical battery cell 20 is depressurized, which is conducive to improving the timeliness of the cylindrical battery cell 20. When S3 / S2≤90%, the area of the region defined by the first circular line 243 is not too large, which can reduce the risk of the weak section 2411 being cracked due to the change of the air pressure inside the cylindrical battery cell 20, which is conducive to improving the reliability of the cylindrical battery cell 20. Therefore, when 10%≤S3 / S2≤90%, the timeliness and reliability of the battery cell can be considered.

[0218] Optionally, 20%≤S3 / S2≤55%.

[0219] The ratio of the area of the region defined by the first circular line 243 to the area of the orthographic projection of the first wall portion 213 along the axial direction of the cylindrical battery cell 20 can be: S3 / S2=20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.

[0220] When S3 / S2≥20%, the area of the region defined by the first circular line 243 is larger, so that the region defined by the first circular line 243 is more easily affected by the discharge inside the cylindrical battery cell 20, thereby opening in time when the cylindrical battery cell 20 is depressurized, which is conducive to improving the timeliness of the cylindrical battery cell 20. When S3 / S2≤55%, the area of the region defined by the first circular line 243 is not too large, which can reduce the risk of the weak section 2411 being cracked due to the change of the air pressure inside the cylindrical battery cell 20, which is conducive to improving the reliability of the cylindrical battery cell 20. Therefore, when 20%≤S3 / S2≤55%, the timeliness and reliability of the battery cell can be considered.

[0221] Please refer to Figure 13 and Figure 14 In some embodiments, the first wall portion 213 is provided with a lead-out hole 231, the electrode terminal 23 is at least partially arranged in the lead-out hole 231, and a plurality of groove sections 2421 are arranged around the lead-out hole 231. In the radial direction of the cylindrical battery cell 20, the minimum distance L between the groove section 2421 and the lead-out hole 231 satisfies: 1mm≤L≤4mm.

[0222] A plurality of groove segments 2421 are arranged around the lead-out hole 231 along the circumferential direction of the cylindrical battery monomer 20, and the plurality of groove segments 2421 are arranged at intervals. The distance between each adjacent two groove segments 2421 can be the same, and in this case, the plurality of groove segments 2421 are arranged at equal intervals along the circumferential direction of the cylindrical battery monomer 20. The distance between each adjacent two groove segments 2421 along the circumferential direction of the cylindrical battery monomer 20 can also be different, and in this case, the plurality of groove segments 2421 are arranged at unequal intervals along the circumferential direction of the cylindrical battery monomer 20.

[0223] L represents the minimum distance between the groove segment 2421 and the lead-out hole 231 along the radial direction of the cylindrical battery monomer 20. The minimum distance between the plurality of groove segments 2421 and the lead-out hole 231 along the radial direction of the cylindrical battery monomer 20 can be equal, and the minimum distance between the plurality of groove segments 2421 and the lead-out hole 231 along the radial direction of the cylindrical battery monomer 20 can also be different.

[0224] The minimum distance between the groove segment 2421 and the lead-out hole 231 along the radial direction of the cylindrical battery monomer 20 can be: L = 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, etc.

[0225] When L ≤ 4 mm, the minimum distance between the groove segment 2421 and the lead-out hole 231 along the radial direction of the cylindrical battery monomer 20 is small, so that the area near the lead-out hole 231 is relatively weak. In this way, the first wall portion 213 is easy to crack from the position of the lead-out hole 231 when the cylindrical battery monomer 20 is depressurized, and then the first wall portion 213 can tear along the extension direction of the groove segment 2421, thereby opening a larger opening, facilitating the discharge of the discharge material in the cylindrical battery monomer 20 to the outside. In this process, the electrode terminal 23 not only can be displaced under the action of the first wall portion 213, but also can move outward under the action of the discharge material, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially destroyed, thereby reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery monomer 20. When L ≥ 1 mm, the minimum distance between the groove segment 2421 and the lead-out hole 231 along the radial direction of the cylindrical battery monomer 20 is not too small, which can reduce the risk of the weak section 2411 cracking due to the change of the gas pressure inside the cylindrical battery monomer 20, and is conducive to improving the reliability of the cylindrical battery monomer 20. Therefore, when 1 mm ≤ L ≤ 4 mm, the cylindrical battery monomer 20 has high reliability.

[0226] Please refer to Figure 15 In some embodiments, the first wall portion 213 is provided with a lead-out hole 231, and the electrode terminal 23 is at least partially arranged in the lead-out hole 231. The area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 is S4, and the area of the orthogonal projection of the first wall portion 213 is S2, which satisfies: 15% ≤ S4 / S2 ≤ 85%.

[0227] S4 represents the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20, that is, the area of the lead-out hole 231.

[0228] S4 / S2 represents the ratio of the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 to the area of the orthogonal projection of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20.

[0229] The ratio of the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 to the area of the orthogonal projection of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 can be: S4 / S2 = 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, and the like.

[0230] When S4 / S2≥15%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 is large, and the lead-out hole 231 is large, so that the strength of the first wall portion 213 is low, so that when the cylindrical battery monomer 20 is pressure released, the first wall portion 213 is easily at least partially opened, thereby driving the electrode terminal 23 to displace, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and is beneficial to improve the reliability of the cylindrical battery monomer 20. When S4 / S2≤85%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 is not too large, and the lead-out hole 231 is not too large, so that the first wall portion 213 has sufficient strength to resist external impact, thereby protecting the electrode assembly 22 and reducing the risk of the first wall portion 213 being cracked due to the change of the internal gas pressure of the cylindrical battery monomer 20, thereby improving the reliability of the cylindrical battery monomer 20. Therefore, when 15%≤S4 / S2≤85%, the cylindrical battery monomer 20 has high reliability.

[0231] Optionally, 25%≤S4 / S2≤55%.

[0232] The ratio of the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 to the area of the orthogonal projection of the first wall portion 213 along the axial direction of the cylindrical battery monomer 20 can be: S4 / S2 = 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, and the like.

[0233] When S4 / S2≥25%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 is larger, the lead-out hole 231 is larger, and the strength of the first wall part 213 is lower. Thus, when the cylindrical battery monomer 20 is depressurized, the first wall part 213 is more likely to at least partially open, thereby causing the electrode terminal 23 to displace, causing the connection position of the electrode terminal 23 and the tab 222 to be at least partially damaged, reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and improving the reliability of the cylindrical battery monomer 20. When S4 / S2≤55%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 along the axial direction of the cylindrical battery monomer 20 is not too large, the lead-out hole 231 is not too large, and the first wall part 213 has sufficient strength to resist external impact, thereby protecting the electrode assembly 22 and reducing the risk of the first wall part 213 cracking due to changes in the internal pressure of the cylindrical battery monomer 20, thereby improving the reliability of the cylindrical battery monomer 20. Therefore, when 25%≤S4 / S2≤55%, the cylindrical battery monomer 20 has higher reliability.

[0234] Please refer to Figure 13 and Figure 14 In some embodiments, the thickness of the weak part 241 is H1, and the thickness of the first wall part 213 is H2, satisfying: 0.05≤H1 / H2≤0.9.

[0235] H1 represents the thickness of the weak part 241. When measuring, the thickness of the weak part 241 at different positions can be measured multiple times and the average value is taken as H1.

[0236] H2 represents the thickness of the first wall part 213. When measuring, the thickness of the first wall part 213 at positions other than the weak part 241 can be measured as H2.

[0237] H1 / H2 represents the ratio of the thickness of the weak part 241 to the thickness of the first wall part 213.

[0238] The ratio of the thickness of the weak part 241 to the thickness of the first wall part 213 can be: H1 / H2=0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, etc.

[0239] When H1 / H2≥0.05, the thickness of the weak portion 241 is large, which can reduce the risk of the weak portion 241 cracking due to the change of the gas pressure inside the cylindrical battery cell 20, and is beneficial to improve the reliability of the cylindrical battery cell 20. When H1 / H2≤0.9, the thickness of the weak portion 241 is not too large, which is beneficial to make the weak portion 241 crack in time when the cylindrical battery cell 20 is depressurized, and is beneficial to improve the timeliness of the cylindrical battery cell 20. Therefore, when 0.05≤H1 / H2≤0.9, the thickness of the weak portion 241 is moderate, the weak portion 241 neither easily cracks due to the change of the gas pressure inside the cylindrical battery cell 20, nor can crack in time when the cylindrical battery cell 20 is depressurized, which is beneficial to improve the timeliness of the cylindrical battery cell 20.

[0240] Optionally, 0.35≤H1 / H2≤0.65.

[0241] The ratio of the thickness of the weak portion 241 to the thickness of the first wall portion 213 can be: H1 / H2=0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.65, etc.

[0242] When H1 / H2≥0.35, the thickness of the weak portion 241 is larger, which can further reduce the risk of the weak portion 241 cracking due to the change of the gas pressure inside the cylindrical battery cell 20, and is beneficial to improve the reliability of the cylindrical battery cell 20. When H1 / H2≤0.65, the thickness of the weak portion 241 is not too large, which is beneficial to make the weak portion 241 crack in time when the cylindrical battery cell 20 is depressurized, and is beneficial to improve the timeliness of the cylindrical battery cell 20. Therefore, when 0.35≤H1 / H2≤0.65, the thickness of the weak portion 241 is more moderate, the weak portion 241 neither easily cracks due to the change of the gas pressure inside the cylindrical battery cell 20, nor can crack in time when the cylindrical battery cell 20 is depressurized, which is beneficial to improve the timeliness of the cylindrical battery cell 20.

[0243] Please refer to Figure 13 and Figure 14 In some embodiments, the first wall portion 213 is provided with a first groove 242, and the first wall portion 213 forms a weak portion 241 in the area where the first groove 242 is provided.

[0244] The weak portion 241 is formed on the wall portion by opening the first groove 242 on the first wall portion 213, and the first wall portion 213 cracks along at least part of the first groove 242 when the battery cell is depressurized, which is simple, convenient, and low in cost.

[0245] In some embodiments, the first recess 242 is arranged on a surface of the first wall portion 213 facing the inside of the case 21. And / or the first recess 242 is arranged on a surface of the first wall portion 213 facing away from the inside of the case 21.

[0246] The first recess 242 can be arranged only on the surface of the first wall portion 213 facing the inside of the case 21, that is, the first recess 242 can be arranged only on the inner surface of the first wall portion 213. The first recess 242 can also be arranged only on the surface of the first wall portion 213 facing away from the inside of the case 21, that is, the first recess 242 can be arranged only on the outer surface of the first wall portion 213. The first recess 242 can also be arranged on both the surface of the first wall portion 213 facing the inside of the case 21 and the surface of the first wall portion 213 facing away from the inside of the case 21, that is, the first recess 242 is arranged on both the inner surface of the first wall portion 213 and the outer surface of the first wall portion 213.

[0247] When the first recess 242 is arranged on the surface of the first wall portion 213 facing the inside of the case 21, the first recess 242 faces the inside of the battery cell, and the first recess 242 is not exposed to the outside of the cylindrical battery cell 20, reducing the risk of the position of the first wall portion 213 where the first recess 242 is arranged being oxidized due to being exposed to the outside of the cylindrical battery cell 20. When the first recess 242 is arranged on the surface of the first wall portion 213 facing away from the inside of the case 21, the manufacturing is simple and convenient, and the cost is lower.

[0248] In some embodiments, the case 21 includes a shell 211 and an end cover 212, the shell 211 includes an integrally formed bottom wall 2112 and a side wall 2111, one end of the side wall 2111 is arranged around the bottom wall 2112, the other end of the side wall 2111 is closed to form an opening, and the end cover 212 closes the opening. The bottom wall 2112 is the first wall portion 213.

[0249] The shell 211 includes an integrally formed side wall 2111 and bottom wall 2112, that is, the shell 211 is processed by an integrally forming process, such as stamping, casting, or extrusion forming, and the like. That is, the side wall 2111 and the bottom wall 2112 of the shell 211 are of an integral structure. The first wall portion 213 is the bottom wall 2112 of the shell 211 arranged opposite to the end cover 212 in the axial direction of the cylindrical battery cell 20.

[0250] The bottom wall 2112 is the first wall portion 213, and the electrode terminal 23 is arranged on the bottom wall 2112, so that the electrode terminal 23 is convenient to install, which is conducive to accurate installation of the electrode terminal 23 and makes the stability of the connection between the electrode terminal 23 and the electrode assembly 22 higher. In addition, the bottom wall 2112 is provided with a weak portion 241, so that the cylindrical battery cell 20 can be relieved from the side where the bottom wall 2112 is located when pressure relief, which facilitates the arrangement of a thermal management component on the side where the end cover 212 is located to manage the temperature of the cylindrical battery cell 20.

[0251] The application also provides a battery device 100, which comprises the cylindrical battery cell 20.

[0252] The application also provides a power consumption device, which comprises the cylindrical battery cell 20.

[0253] According to some embodiments of the application, please refer to Figures 3 to 15 .

[0254] The application provides a cylindrical battery cell 20, which comprises a shell 21, an electrode assembly 22 and an electrode terminal 23. The shell 21 has a first wall portion 213. The electrode assembly 22 is at least partially accommodated in the shell 21 and comprises a tab 222. The electrode terminal 23 is arranged on the first wall portion 213 and electrically connected with the electrode assembly 22. The first wall portion 213 has a weak portion 241 configured to be damaged when the cylindrical battery cell 20 is depressurized, so that at least part of the first wall portion 213 is opened, and the first wall portion 213 can drive the electrode terminal 23 to move in a direction away from the tab 222 when opened, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially damaged. The first wall portion 213 of the cylindrical battery cell 20 can be at least partially opened along at least part of the weak portion 241 when the cylindrical battery cell 20 is depressurized, so that the first wall portion 213 is at least partially opened, thereby facilitating the discharge of the discharge material in the cylindrical battery cell 20 to the outside, achieving depressurization. In this process, the electrode terminal 23 is displaced under the driving of the first wall portion 213, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, facilitating the suppression of further development of thermal runaway, and improving the reliability of the cylindrical battery cell 20.

[0255] The weak portion 241 is arranged around the electrode terminal 23. The weak portion 241 is arranged around the electrode terminal 23, so that the first wall portion 213 is relatively weak in the area around the electrode terminal 23. In this way, when the cylindrical battery cell 20 is depressurized, the first wall portion 213 in the area around the electrode terminal 23 is more likely to locally deform or locally detach, thereby facilitating the displacement of the electrode terminal 23, causing the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, causing the cylindrical battery cell 20 to be open-circuited when depressurized, thereby suppressing the further development of thermal runaway and improving the reliability of the cylindrical battery cell 20.

[0256] In some embodiments, the weakened portion 241 is circular. When the weakened portion 241 is circular, the force on each position of the weakened portion 241 is more uniform, and the first wall portion 213 is more likely to crack along the entire circumference of the weakened portion 241 when the cylindrical battery cell 20 is depressurized, so that the pressure relief portion 244 is more easily separated from the first wall portion 213 to open a larger opening for pressure relief, thereby improving the timeliness of the pressure relief of the cylindrical battery cell 20 and improving the reliability of the cylindrical battery cell 20. In addition, when the pressure relief portion 244 is separated from the first wall portion 213, the electrode terminal 23 is displaced to a greater extent, which more easily causes the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, thereby inhibiting further development of thermal runaway and improving the reliability of the cylindrical battery cell 20.

[0257] In other embodiments, the weakened portion 241 includes a plurality of weakened segments 2411 that are spaced apart along the circumference of the cylindrical battery cell 20. By spacing the plurality of weakened segments 2411 along the circumference of the cylindrical battery cell 20, the first wall portion 213 can crack along at least one of the weakened segments 2411 when the cylindrical battery cell 20 is depressurized, so that the first wall portion 213 is at least partially opened to facilitate the discharge of the contents of the cylindrical battery cell 20 to the outside environment and achieve pressure relief. In this process, the electrode terminal 23 is displaced under the action of the first wall portion 213, and the connection position between the electrode terminal 23 and the tab 222 is at least partially destroyed, reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting further development of thermal runaway and improving the reliability of the cylindrical battery cell 20. Along the circumference of the cylindrical battery cell 20, the portion of the first wall portion 213 between adjacent weakened segments 2411 has a higher strength, which is beneficial to reducing the risk of the weakened portion 241 cracking due to changes in the internal pressure of the cylindrical battery cell 20 and improving the reliability of the cylindrical battery cell 20.

[0258] The first wall portion 213 is provided with a first groove 242, and the first groove 242 includes a plurality of groove segments 2421 that are spaced apart along the circumference of the cylindrical battery cell 20. The groove bottom wall 2112 of each groove segment 2421 forms a weakened segment 2411. By forming the weakened portion 241 on the first wall portion 213 in the form of the first groove 242, the first groove 242 can include a plurality of groove segments 2421 that are spaced apart along the circumference of the cylindrical battery cell 20, and the groove bottom wall 2112 of each groove segment 2421 corresponds to form a weakened segment 2411. The first wall portion 213 can crack along at least one of the groove segments 2421 when the cylindrical battery cell 20 is depressurized, so that the first wall portion 213 is at least partially opened to facilitate the discharge of the contents of the cylindrical battery cell 20 to the outside environment, which is simple and convenient and has a low cost.

[0259] The first wall portion 213 is provided with a lead-out hole 231, and the electrode terminal 23 is at least partially arranged in the lead-out hole 231, and a plurality of groove segments 2421 are arranged around the lead-out hole 231. The groove segments 2421 extend in the radial direction of the cylindrical battery cell 20, and the first wall portion 213 is configured to be broken from the lead-out hole 231 and torn along at least part of the groove segments 2421 when the cylindrical battery cell 20 is depressurized. By extending the groove segments 2421 in the radial direction of the cylindrical battery cell 20, the first wall portion 213 can be broken from the position of the lead-out hole 231 where the electrode terminal 23 is arranged first when the cylindrical battery cell 20 is depressurized, and then the first wall portion 213 can be torn along the extension direction of the groove segments 2421, thereby opening a larger opening, facilitating the discharge of the discharge material in the cylindrical battery cell 20 to the outside. In this process, the electrode terminal 23 not only can be displaced under the action of the first wall portion 213, but also can be moved outward under the action of the discharge material, so that the connection position of the electrode terminal 23 and the tab 222 is at least partially damaged, thereby reducing the overcurrent capacity between the electrode terminal 23 and the tab 222, thereby inhibiting the further development of thermal runaway, and facilitating the improvement of the reliability of the cylindrical battery cell 20.

[0260] In some embodiments, the groove segments 2421 are equal-width grooves extending along a straight trajectory. By arranging the groove segments 2421 as equal-width grooves extending along a straight trajectory, it is simple and convenient to manufacture, thereby facilitating the reduction of manufacturing cost.

[0261] In other embodiments, the groove width of the groove segments 2421 gradually increases from one end of the groove segments 2421 close to the electrode terminal 23 to the other end of the groove segments 2421 away from the electrode terminal 23. By gradually increasing the groove width of the groove segments 2421 from one end of the groove segments 2421 close to the electrode terminal 23 to the other end of the groove segments 2421 away from the electrode terminal 23, it is beneficial to reduce the resistance of the first wall portion 213 torn along the extension direction of the groove segments 2421, and a larger opening can be quickly opened when the cylindrical battery cell 20 is depressurized, thereby facilitating the rapid depressurization of the cylindrical battery cell 20, and facilitating the improvement of the timeliness of the depressurization of the cylindrical battery cell 20.

[0262] The first wall portion 213 is provided with a lead-out hole 231, and the electrode terminal 23 is at least partially arranged in the lead-out hole 231. In the axial direction of the cylindrical battery monomer 20, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 is S4, and the area of the orthogonal projection of the first wall portion 213 is S2, and it is satisfied that 25%≤S4 / S2≤55%. When S4 / S2≥25%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 in the axial direction of the cylindrical battery monomer 20 is larger, the lead-out hole 231 is larger, and the strength of the first wall portion 213 is lower, so that the first wall portion 213 is more likely to be locally deformed or locally separated when the cylindrical battery monomer 20 is pressure released, thereby causing the electrode terminal 23 to be displaced, causing the electrical connection between the electrode terminal 23 and the electrode assembly 22 to fail, causing the cylindrical battery monomer 20 to be disconnected when pressure released, thereby inhibiting the further development of thermal runaway, and is beneficial to improve the reliability of the cylindrical battery monomer 20. When S4 / S2≤55%, the area surrounded by the orthogonal projection of the hole wall surface of the lead-out hole 231 in the axial direction of the cylindrical battery monomer 20 is not too large, the lead-out hole 231 is not too large, and the first wall portion 213 has sufficient strength to resist external impact, thereby protecting the electrode assembly 22 and reducing the risk of the first wall portion 213 being cracked due to the change in internal pressure of the cylindrical battery monomer 20, and is beneficial to improve the reliability of the cylindrical battery monomer 20. Therefore, when 25%≤S4 / S2≤55%, the cylindrical battery monomer 20 has higher reliability.

[0263] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A cylindrical battery cell, characterized by, include: The outer casing has a first wall portion; An electrode assembly, at least partially housed within the housing, the electrode assembly including tabs; An electrode terminal is disposed on the first wall portion, and the electrode terminal is electrically connected to the electrode tab. The first wall portion has a weak portion, which is configured to be destroyed when the cylindrical battery cell is depressurized, so that at least a portion of the first wall portion is opened, and when the first wall portion is opened, it can drive the electrode terminal to move away from the tab, so that the connection position between the electrode terminal and the tab is at least partially destroyed.

2. The cylindrical battery cell of claim 1, wherein, When the first wall portion is opened, it can disconnect the circuit between the electrode terminal and the tab.

3. The cylindrical battery cell of claim 1, wherein, The weak portion is arranged around the electrode terminal.

4. The cylindrical battery cell of claim 3, wherein, The first wall portion has a pressure relief portion, the electrode terminal is disposed in the pressure relief portion, the weak portion is an annular structure, and the weak portion is disposed around the pressure relief portion and the electrode terminal.

5. The cylindrical battery cell of claim 4, wherein, The weak point is circular.

6. The cylindrical battery cell of claim 4, wherein, Along the axial direction of the cylindrical battery cell, the area of ​​the orthographic projection of the pressure relief portion is S1, and the area of ​​the orthographic projection of the first wall portion is S2, satisfying: 10% ≤ S1 / S2 ≤ 90%.

7. The cylindrical battery cell of claim 6, wherein, 20% ≤ S1 / S2 ≤ 55%.

8. The cylindrical battery cell of claim 4, wherein, The first wall portion is provided with a plurality of weak portions, which are arranged radially along the cylindrical battery cell.

9. The cylindrical battery cell according to claim 3, characterized in that, The weak part includes multiple weak segments, which are spaced apart circumferentially along the cylindrical battery cell.

10. The cylindrical battery cell according to claim 9, characterized in that, The first wall portion is provided with a first groove, the first groove includes multiple groove segments, the multiple groove segments are arranged at intervals along the circumference of the cylindrical battery cell, and the bottom wall of each groove segment forms a weak segment.

11. The cylindrical battery cell according to claim 10, characterized in that, The groove extends circumferentially along the cylindrical battery cell. Along the circumferential direction of the cylindrical battery cell, the first wall portion is configured to split and tear the portion of the first wall portion located between two adjacent groove segments when the cylindrical battery cell is depressurized.

12. The cylindrical battery cell according to claim 10, characterized in that, The first wall portion is provided with an outlet hole, and the electrode terminal is at least partially inserted into the outlet hole, and a plurality of the slot segments are arranged around the outlet hole; The groove extends radially along the cylindrical battery cell, and the first wall is configured to crack from the outlet hole and tear along at least a portion of the groove when the cylindrical battery cell is depressurized.

13. The cylindrical battery cell according to claim 12, characterized in that, The groove segment is a uniform width groove extending along a straight trajectory.

14. The cylindrical battery cell according to claim 12, characterized in that, The width of the groove gradually increases from the end of the groove closer to the electrode terminal to the end of the groove farther from the electrode terminal.

15. The cylindrical battery cell according to claim 10, characterized in that, Along the radial direction of the cylindrical battery cell, the groove segment includes a first end away from the electrode terminal, the first ends of the plurality of groove segments are located on a first circular line, the area of ​​the region defined by the first circular line is S3, and along the axial direction of the cylindrical battery cell, the area of ​​the orthographic projection of the first wall portion is S2, satisfying: 10% ≤ S3 / S2 ≤ 90%.

16. The cylindrical battery cell according to claim 15, characterized in that, 20% ≤ S3 / S2 ≤ 55%.

17. The cylindrical battery cell according to claim 10, characterized in that, The first wall portion is provided with an outlet hole, and the electrode terminal is at least partially inserted into the outlet hole, and a plurality of the slot segments are arranged around the outlet hole; Along the radial direction of the cylindrical battery cell, the minimum distance between the groove and the lead-out hole is L, which satisfies: 1mm≤L≤4mm.

18. The cylindrical battery cell according to any one of claims 1-17, characterized in that, The first wall portion is provided with an outlet hole, and the electrode terminal is at least partially inserted into the outlet hole; Along the axial direction of the cylindrical battery cell, the area enclosed by the orthographic projection of the hole wall of the lead-out hole is S4, and the area of ​​the orthographic projection of the first wall is S2, satisfying: 15% ≤ S4 / S2 ≤ 85%.

19. The cylindrical battery cell according to claim 18, characterized in that, 25% ≤ S4 / S2 ≤ 55%.

20. The cylindrical battery cell according to any one of claims 1-17, characterized in that, The thickness of the weak part is H1, and the thickness of the first wall part is H2, satisfying: 0.05≤H1 / H2≤0.

9.

21. The cylindrical battery cell according to claim 20, characterized in that, 0.35≤H1 / H2≤0.

65.

22. The cylindrical battery cell according to any one of claims 1-17, characterized in that, The first wall portion is provided with a first groove, and the weak portion is formed in the area where the first groove is provided.

23. The cylindrical battery cell according to claim 22, characterized in that, The first groove is disposed on the surface of the first wall portion facing the interior of the housing; and / or The first groove is disposed on the surface of the first wall portion that is away from the interior of the outer casing.

24. The cylindrical battery cell according to any one of claims 1-17, characterized in that, The outer casing includes: The housing includes an integrally formed bottom wall and a side wall, one end of the side wall surrounding the bottom wall and the other end of the side wall forming an opening; End cap, to close the opening; The bottom wall is the first wall portion.

25. A battery device, characterized in that, Includes the cylindrical battery cell according to any one of claims 1-24.

26. An electrical appliance, characterized in that, Includes a cylindrical battery cell according to any one of claims 1-24, the cylindrical battery cell being used to provide electrical energy to the electrical device.

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