Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, an electrode assembly and a current collecting member. The electrode assembly comprises a main body and a first tab, and the first tab is arranged at one end of the main body facing the first wall in the first direction. The current collecting member comprises a current collecting body and a first protrusion. In the first direction, at least part of the current collecting body is located between the first tab and the first wall of the shell. The first protrusion is arranged on the first surface of the current collecting body facing the first wall, and the first protrusion is welded to the first wall. Part of the current collecting body is arranged outside the first protrusion and connected to the first tab. The first protrusion comprises a side wall and an end wall. The side wall extends along the circumference of the end wall. One end of the side wall is connected to the current collecting body, and the other end is connected to the end wall. The end wall is welded to the first wall. The minimum thickness of the side wall is greater than the maximum thickness of the current collecting body, which can improve the reliability of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Currently, batteries are widely used in new energy vehicles, electronic devices, and other fields. As the demand for batteries increases, higher requirements are being placed on their reliability. Utility Model Content

[0003] This application provides a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery cell.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a casing, an electrode assembly, and a current collector; the casing includes a first wall; the electrode assembly is housed within the casing, the electrode assembly including a main body and a first tab, the first tab being disposed at one end of the main body facing the first wall along a first direction; the current collector includes a current collector body and a first protrusion, at least a portion of the current collector body is located between the first tab and the first wall along the first direction, the current collector body has a first surface facing the first wall, the first protrusion is disposed on the first surface, the first protrusion is welded to the first wall, a portion of the current collector body is disposed around the outside of the first protrusion and connected to the first tab; the first protrusion includes a side wall and an end wall, the side wall is located between the end wall and the current collector body along the first direction, the side wall extends circumferentially along the end wall, one end of the side wall is connected to the current collector body, the other end is connected to the end wall, the end wall is welded to the first wall, and the minimum thickness of the side wall is greater than the maximum thickness of the current collector body.

[0005] In the above technical solution, a portion of the current collector body is arranged around the outside of the first protrusion and connected to the first tab. The end wall of the first protrusion is welded to the first wall. The side wall is located between the current collector body and the end wall along the first direction. The current of the first tab of the electrode assembly passes through the current collector body and the side wall in sequence and then reaches the first wall. The minimum thickness of the side wall is greater than the maximum thickness of the current collector body. This can improve the current carrying capacity of the portion of the first protrusion located in the current path between the first tab and the first wall, reduce the risk of the side wall being melted when the current flows through the first protrusion, improve the stability of the electrical connection between the first wall and the first tab, and thus improve the reliability of the battery cell.

[0006] In some embodiments of the first aspect of this application, the first protrusion is welded to the first wall to form a first weld mark, and the minimum thickness of the end wall located in the area surrounding the first weld mark is greater than the maximum thickness of the current collector body.

[0007] In the above technical solution, the minimum thickness of the area of ​​the end wall of the first protrusion located on the outer periphery of the first solder mark is greater than the maximum thickness of the current collector body, which can improve the overall current carrying capacity of the first protrusion, further reduce the risk of the first protrusion being melted when current flows through the first protrusion, further improve the stability of the electrical connection between the first wall and the first electrode tab, and thus further improve the reliability of the battery cell.

[0008] In some embodiments of the first aspect of this application, the current collector body is welded to the first electrode tab to form a second solder mark; the second solder mark is disposed around the first protrusion, or there are multiple second solder marks, and the multiple second solder marks are disposed at circumferential intervals along the first protrusion.

[0009] In the above technical solution, the current collector body is welded to the first electrode tab to form a second solder mark, which facilitates the electrical connection between the current collector body and the first electrode tab and ensures good stability of the electrical connection. The second solder mark is arranged around the first protrusion, resulting in a larger connection area between the first electrode tab and the current collector body, which is beneficial to improving the current carrying capacity. There are multiple second solder marks, which are spaced apart circumferentially along the first protrusion. Along the circumference of the first protrusion, the space between two adjacent second solder marks provides space for electrolyte flow and gas emission from inside the electrode assembly, which is beneficial to improving the wetting efficiency and performance of the electrode assembly, as well as facilitating the external venting of the electrode assembly, reducing the risk of accidents such as explosions and fires, and improving the reliability of the battery cell.

[0010] In some embodiments of the first aspect of this application, the first wall is provided with a through hole, the through hole penetrates the first wall, at least a portion of the first protrusion passes through the through hole and is welded to the first wall to form a first weld mark portion.

[0011] In the above technical solution, a through hole is provided in the first wall, and at least a portion of the first protrusion passes through the through hole of the first wall and is welded to the first wall to form a first weld mark. This allows welding to be performed from the outside of the first wall, and the welding status between the first protrusion and the first wall is visible during the welding process, enabling real-time assessment of the welding condition and making the connection more convenient. The first protrusion passing through the through hole of the first wall also serves a positioning function, improving the stability of the connection between the first wall and the first protrusion.

[0012] In some embodiments of the first aspect of this application, the first wall has an inner surface facing the body portion, one end of the through hole extends to the inner surface, and the inner surface is closer to the body portion than the first solder mark portion.

[0013] In the above technical solution, one end of the through hole extends to the inner surface of the first wall facing the main body. The inner surface of the first wall is closer to the main body than the first solder mark. Therefore, the first solder mark does not extend to the inner surface or does not extend to a position flush with the inner surface of the first wall. This makes a part of the first wall located on the side of the first solder mark facing the electrode assembly, reducing the risk of leakage at or near the first solder mark and improving the reliability of the battery cell.

[0014] In some embodiments of the first aspect of this application, along the first direction, the minimum distance between the first solder mark and the inner surface is H, where 0.5mm≤H≤1.5mm.

[0015] In the above technical solution, by ensuring that H is greater than or equal to 0.5 mm, the size of the portion of the first wall located on the side of the first solder joint facing the electrode assembly is relatively large, reducing the risk of leakage from the first wall or the first solder joint and improving the reliability of the battery cell. By ensuring that H is less than or equal to 1.5 mm, the size of the portion of the first wall located on the side of the first solder joint facing the electrode assembly is not too large, which is beneficial for the first solder joint to have a larger size in the first direction, improving the welding strength of the first wall and the first protrusion, thereby enabling the battery cell to have better reliability. Therefore, 0.5 mm ≤ H ≤ 1.5 mm can reduce the risk of battery cell leakage and improve the welding strength of the first wall and the first protrusion, thereby enabling the battery cell to have high reliability.

[0016] In some embodiments of the first aspect of this application, 0.8mm ≤ H ≤ 1mm.

[0017] In the above technical solution, by making H greater than or equal to 0.8 mm, the size of the portion of the first wall located on the side of the first solder joint facing the electrode assembly is larger, which can further reduce the risk of leakage from the first wall or the first solder joint and further improve the reliability of the battery cell. When H is less than or equal to 1 mm, the size of the portion of the first wall located on the side of the first solder joint facing the electrode assembly is not too large, which is beneficial for the first solder joint to have a larger size in the first direction, further improving the welding strength of the first wall and the first protrusion, thereby making the battery cell have better reliability. Therefore, 0.8 mm ≤ H ≤ 1 mm can further reduce the risk of battery cell leakage and improve the welding strength of the first wall and the first protrusion, thereby making the battery cell have higher reliability.

[0018] In some embodiments of the first aspect of this application, the hole wall surface of the through hole includes a first wall surface and a chamfered surface arranged along the first direction, the chamfered surface connecting the first wall surface and the inner surface, and the end of the first wall surface away from the chamfered surface being connected to the surface of the first solder mark portion.

[0019] In the above technical solution, when the hole wall surface of the through hole includes a chamfered surface connected to the inner surface of the first wall, the chamfered surface and the first solder mark are connected through the first hole wall surface. In this case, the first solder mark does not extend to the chamfered surface, so that the first solder mark does not extend to the inner surface or does not extend to a position flush with the inner surface. This makes a part of the first wall located on the side of the first solder mark facing the electrode assembly, reducing the risk of leakage at or near the first solder mark and improving the reliability of the battery cell.

[0020] In some embodiments of the first aspect of this application, the first wall is provided with a shielding member, the shielding member is located on the side of the first solder mark portion away from the main body portion, and in a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the shielding member overlaps with at least a portion of the orthographic projection of the first solder mark portion; at least a portion of the shielding member is located within the through hole.

[0021] In the above technical solution, by positioning the shielding member on the side of the first solder mark away from the main body, and ensuring that at least a portion of the orthographic projection of the shielding member overlaps with at least a portion of the orthographic projection of the first solder mark in a projection plane perpendicular to the first direction, the shielding member can protect the first solder mark, reducing the risk of damage to the first solder mark by external forces, thereby reducing the risk of welding failure of the first wall and the second region, and thus improving the reliability of the battery cell. Furthermore, by positioning at least a portion of the shielding member within a through-hole, the space occupied by the shielding member on the external surface of the casing is reduced or avoided, thus reducing the volume of the battery cell.

[0022] In some embodiments of the first aspect of this application, the through hole includes a first hole segment and a second hole segment. Along the first direction, the first hole segment is further away from the main body than the second hole segment. The hole wall surface of the first hole segment and the hole wall surface of the second hole segment are connected by a first stepped surface. The cross-sectional area of ​​the first hole segment is larger than the cross-sectional area of ​​the second hole segment. At least a portion of the first protrusion is located in the second hole segment, and the cross-section is perpendicular to the first direction. At least a portion of the shielding member is accommodated in the first hole segment and abuts against the first stepped surface.

[0023] In the above technical solution, by at least partially accommodating the shielding member within the first hole segment, the space occupied by the shielding member on the outside of the casing is reduced or avoided, thereby reducing the volume of the battery cell. The shielding member abuts against the first stepped surface, facilitating its installation, and the first stepped surface also limits the shielding member, preventing it from moving further into the through hole and improving its stability.

[0024] In some embodiments of the first aspect of this application, a portion of the first protrusion is accommodated in the first hole segment, a clearance groove is provided on the side of the shield facing the first step surface, and the end of the first protrusion away from the current collecting body extends to the clearance groove.

[0025] In the above technical solution, by providing a clearance groove on the side of the shielding member facing the first step surface, and extending the end of the first protrusion away from the current collecting body to the clearance groove, it is convenient to set the first protrusion and the shielding member, and the risk of interference between the shielding member and the first protrusion is reduced.

[0026] In some embodiments of the first aspect of this application, the through hole includes a first hole segment and a second hole segment. Along the first direction, the first hole segment is further away from the main body than the second hole segment. The hole wall surface of the first hole segment and the hole wall surface of the second hole segment are connected by a first stepped surface. The cross-sectional area of ​​the first hole segment is larger than the cross-sectional area of ​​the second hole segment. At least a portion of the first protrusion is located in the second hole segment. The first wall has opposing inner and outer surfaces. One end of the through hole extends to the inner surface, and the other end of the through hole extends to the outer surface. A portion of the first solder mark extends from the first stepped surface in a direction from the outer surface toward the inner surface, and another portion of the first solder mark is accommodated in the first hole segment.

[0027] In the above technical solution, a portion of the first solder mark extends from the first step surface along the outer surface of the first wall toward the inner surface of the first wall, and another portion of the first solder mark is accommodated in the first hole section. This reduces the risk of the first solder mark protruding from the outer surface of the first wall, reduces the risk of the first solder mark being damaged by external forces, and avoids or reduces the space occupied by the first solder mark on the outer surface of the casing, thereby reducing the size of the battery cell.

[0028] In some embodiments of the first aspect of this application, the first protrusion abuts against the first wall, thereby forming a first gap between the first surface and the first wall.

[0029] In the above technical solution, the first protrusion abuts against the first wall, and a first gap is formed between the first surface and the first wall. The electrode assembly can exhaust gas outward through the first gap, which can improve exhaust efficiency and facilitate timely pressure relief of the battery cell, reduce the risk of explosion, fire and other problems, and improve the reliability of the battery cell.

[0030] In some embodiments of the first aspect of this application, the edge of the current collecting body is provided with an edge portion, the edge portion protruding from the first surface, and a second gap is formed between the edge portion and the first wall. Along the first direction, the size of the second gap is H1, 0.2mm≤H1≤1mm.

[0031] In the above technical solution, a second gap is formed between the edge and the first wall. This second gap facilitates the outward venting of air from the electrode assembly, improving venting efficiency and allowing for timely pressure relief of the battery cell, reducing the risk of explosions and fires, and improving the reliability of the battery cell. The second gap also provides space for the current collector to deform closer to the first wall. In the event of abnormal internal pressure in the battery cell, the deformation of the current collector can alleviate the problem. After the current collector component deforms, the edge can abut against the inner surface of the first wall, ensuring that the first gap remains between the inner and first surfaces. This reduces the risk of the first gap being blocked due to deformation of the current collector or the absence of a gap between the first and inner surfaces, thereby reducing the risk of internal pressure buildup leading to explosions and fires in the battery cell and improving its reliability. By ensuring H1 is greater than or equal to 0.2 mm, the second gap is made larger in the first direction, providing a larger venting space between the edge and the inner surface. This improves venting efficiency and facilitates timely pressure relief of the battery cell, reducing the risk of explosions and fires, and enhancing the reliability of the battery cell. It also provides more space for the current collector to deform towards the first wall. In case of abnormal internal pressure in the battery cell, the deformation of the current collector can effectively alleviate the problem. By ensuring H1 is less than or equal to 1 mm, the second gap is not made too large in the first direction, which helps to reduce the size of the battery cell in the first direction and improve the energy density of the battery cell. Therefore, 0.2 mm ≤ H1 ≤ 1 mm ensures that the battery cell has good reliability and energy density.

[0032] Secondly, embodiments of this application provide a battery device, which includes a battery cell provided in any one of the embodiments of the first aspect.

[0033] In the above technical solutions, the battery cell provided in the first aspect embodiment has good reliability, and the battery device including the battery cell also has good reliability.

[0034] Thirdly, embodiments of this application provide an electrical device, which includes a battery cell provided in any embodiment of the first aspect or a battery device provided in any embodiment of the second aspect.

[0035] In the above technical solutions, the reliability of the battery cell provided in the first aspect embodiment and the reliability of the battery device provided in the second aspect embodiment are both good, and the power supply device powered by the battery cell or the battery device also has good power supply reliability. Attached Figure Description

[0036] 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.

[0037] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0038] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0039] Figure 3 Exploded views of a single battery cell provided in some embodiments of this application;

[0040] Figure 4 A schematic diagram of the first wall and the current collection component assembled along a first direction is provided for some embodiments of this application;

[0041] Figure 5 for Figure 4 A sectional view along line A1-A1;

[0042] Figure 6 Schematic diagram of a current collection member having a second solder mark provided in some embodiments of this application;

[0043] Figure 7 A schematic diagram of a current collector with a second solder mark provided for other embodiments of this application;

[0044] Figure 8 Axonometric views of the flow collection components provided in some embodiments of this application;

[0045] Figure 9 for Figure 8 Enlarged view at point B1;

[0046] Figure 10 A schematic diagram of the first wall and the flow collection component assembled along a first direction, provided for another embodiment of this application;

[0047] Figure 11 for Figure 10 A sectional view along line A2-A2;

[0048] Figure 12 A schematic diagram of the first wall and the flow collection component before assembly, provided for some embodiments of this application;

[0049] Figure 13 for Figure 12 Cross-sectional view of the first wall and the flow collection components after assembly;

[0050] Figure 14 A diagram showing the first wall, the current collection member, and the shielding member assembled along a first direction according to some embodiments of this application;

[0051] Figure 15 for Figure 14 A sectional view along line A3-A3;

[0052] Figure 16 A diagram showing the first wall, the current collection member, and the shielding member assembled along a first direction, as provided in other embodiments of this application;

[0053] Figure 17 for Figure 16 A sectional view along line A4-A4;

[0054] Figure 18 A cross-sectional view of the first wall, the flow collecting member, and the shielding member assembled according to some embodiments of this application;

[0055] Figure 19 for Figure 18 A schematic diagram of the first wall, flow collection components, and shielding components before assembly;

[0056] Figure 20 for Figure 18 Enlarged view at B2;

[0057] Figure 21 A schematic diagram of the first wall, the current collection member, and the shielding member assembled along a first direction, provided for further embodiments of this application;

[0058] Figure 22 for Figure 21 Sectional view along line A5-A5;

[0059] Figure 23 for Figure 22 Enlarged view at B3;

[0060] Figure 24 for Figure 21 A schematic diagram of the first wall, flow collection components, and shielding components before assembly;

[0061] Figure 25 A schematic diagram of the first wall, the current collection member, and the shielding member after assembly along a first direction, provided in some further embodiments of this application;

[0062] Figure 26 for Figure 25 Sectional view along line A6-A6;

[0063] Figure 27 for Figure 26 Enlarged view at B4 in the middle;

[0064] Figure 28Axonometric views of the current collection component provided in some embodiments of this application;

[0065] Figure 29 for Figure 28 At point B5;

[0066] Figure 30 A cross-sectional view of the first wall, the flow collecting member, and the shielding member assembled according to some further embodiments of this application;

[0067] Figure 31 Axonometric view of a flow collector provided for further embodiments of this application.

[0068] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing; 12 - Second housing; 20 - Battery cell; 21 - Outer casing; 211 - Housing; 2111 - Opening; 212 - First wall; 2121 - Through hole; 21211 - First wall surface; 21212 - Chamfered surface; 21213 - First hole segment; 21214 - Second hole segment; 21215 - First stepped surface; 2122 - Inner surface of the first wall; 2123 - Outer surface of the first wall; 212' - End cap; 22 - Electrode assembly; 221 - Main body; 222 - First electrode tab; 223 - Second electrode tab; 23 - Electrode terminal; 24 - Current collector; 25 - Current collector component; 251 - Current collector body; 2511 - ... Surface 1; 2512-Second surface; 2513-First groove; 25131-Groove wall of the first groove; 2514-Second groove; 2515-Second protrusion; 2516-Exhaust hole; 252-First protrusion; 2521-Side wall; 2522-End wall; 2523-First part; 25231-Second end face; 2524-Second part; 2525-Transition part; 2526-First end face; 253-Edge part; 2531-First edge part; 2532-Second edge part; 30-Shielding member; 31-Allowing groove; 40-Pressure relief mechanism; X-First direction; Q1-First solder mark part; Q2-Second solder mark part; M-First gap; N-Second gap; 200-Controller; 300-Motor. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0070] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0071] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0072] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0073] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0074] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0075] In this application, "multiple" means two or more (including two).

[0076] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0077] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0078] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0079] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0080] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0081] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0082] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 )), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0083] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0084] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0085] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors 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 substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0086] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0087] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0088] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0089] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0090] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0091] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0092] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0093] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0094] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0095] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from 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 ethers.

[0096] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0097] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0098] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0099] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0100] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0101] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0102] In some implementations, the electrode assembly is a stacked structure.

[0103] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0104] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0105] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0106] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0107] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0108] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0109] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0110] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0111] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0112] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0113] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0114] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0115] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cell assemblies housed within the housing.

[0116] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0117] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0118] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0119] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0120] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0121] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0122] In related technologies, a battery cell includes a casing, an electrode assembly, and a current collector. The electrode assembly and the current collector are housed within the casing. The current collector connects the first tab of the electrode assembly to the wall of the casing. The current collector includes a current collector body and a first protrusion. A portion of the current collector body is arranged around the outside of the first protrusion and connected to the first tab. The first protrusion is connected to the wall of the casing. Along the current flow path, the cross-sectional area decreases from the current collector body to the first protrusion. Therefore, the current flow capacity of the first protrusion is weaker than that of the current collector body. During charging and discharging, the first protrusion is prone to melting due to excessive current, which reduces the reliability of the battery cell.

[0123] Based on the above considerations, in order to improve the reliability of the battery cell, this application provides a battery cell including a casing, an electrode assembly, and a current collector; the casing includes a first wall; the electrode assembly is housed within the casing and includes a main body and a first tab, the first tab being disposed at one end of the main body facing the first wall along a first direction; the current collector includes a current collector body and a first protrusion, at least a portion of the current collector body is located between the first tab and the first wall along the first direction, the current collector body has a first surface facing the first wall, the first protrusion is disposed on the first surface and welded to the first wall, a portion of the current collector body is disposed around the outside of the first protrusion and connected to the first tab; the first protrusion includes a side wall and an end wall, the side wall is located between the end wall and the current collector body along the first direction, the side wall extends circumferentially along the end wall, one end of the side wall is connected to the current collector body, the other end is connected to the end wall, the end wall is welded to the first wall, and the minimum thickness of the side wall is greater than the maximum thickness of the current collector body.

[0124] A portion of the current collector is arranged around the outside of the first protrusion and connected to the first tab. The end wall of the first protrusion is welded to the first wall, and the side wall is located between the current collector and the end wall along the first direction. The current of the first tab of the electrode assembly passes through the current collector and the side wall in sequence and reaches the first wall. The minimum thickness of the side wall is greater than the maximum thickness of the current collector, which can improve the current carrying capacity of the part of the first protrusion located in the current path between the first tab and the first wall, reduce the risk of the side wall being melted when the current flows through the first protrusion, improve the stability of the electrical connection between the first wall and the first tab, and thus improve the reliability of the battery cell.

[0125] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0126] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0127] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0128] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0129] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0130] Please refer to Figure 2 , Figure 2 The exploded view of a battery device 100 provided in some embodiments of this application shows that the battery device 100 may include a housing 10 and a battery cell 20, wherein the housing 10 is used to house the battery cell 20.

[0131] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing 11 and a second housing 12, which are interlocked. The first housing 11 and the second housing 12 can have various shapes, such as cuboids or cylinders. The first housing 11 can be a hollow structure open on one side, and the second housing 12 can also be a hollow structure open on one side. The open side of the second housing 12 interlocks with the open side of the first housing 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing 11 can be a hollow structure open on one side, and the second housing 12 can be a plate-like structure, with the second housing 12 interlocked with the open side of the first housing 11, thus forming a housing 10 with an accommodating space.

[0132] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0133] In some embodiments, the battery device 100 may further include a busbar (not shown in the figure), through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of multiple battery cells 20. The busbar can be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0134] Please refer to Figure 3 , Figure 3 This is an exploded view of a battery cell 20 provided in some embodiments of this application. The battery cell 20 may include a housing 21 and an electrode assembly 22, the electrode assembly 22 being housed within the housing 21.

[0135] In some embodiments, the housing 21 may include a housing 211 and an end cap 212', the housing 211 having an opening 2111, and the end cap 212' closing the opening 2111 of the housing 211. Here, "closed" means covered or shut, and can be either sealed or unsealed.

[0136] The housing 211 is a component used to house the electrode assembly 22. The housing 211 can be a hollow structure with an opening 2111 at one end, or it can be a hollow structure with openings 2111 at both opposite ends. The housing 211 can have various shapes, such as cylindrical or cuboid. The housing 211 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The electrode assembly 22 can be partially or completely located within the housing 211.

[0137] End cap 212' and housing 211 together define a receiving space for accommodating electrode assembly 22 and other components. End cap 212' can be connected to housing 211 by welding, roll sealing, or other methods to close opening 2111 of housing 211. The shape of end cap 212' can be adapted to the shape of housing 211. For example, if housing 211 is a cuboid structure, end cap 212' can be a rectangular plate structure adapted to housing 211; or if housing 211 is a cylindrical structure, end cap 212' can be a circular plate structure adapted to housing 211. The material of end cap 212' can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The materials of end cap 212' and housing 211 can be the same or different.

[0138] In an embodiment where the housing 211 has an opening 2111 at one end, one end cap 212' may be provided. In an embodiment where the housing 211 has openings 2111 at both opposite ends, two end caps 212' may be provided, with the two end caps 212' respectively closing the two openings 2111 of the housing 211, and the two end caps 212' and the housing 211 together defining the receiving space.

[0139] In some embodiments, the battery cell 20 may further include electrode terminals 23, which are disposed on the housing 21 and are used for electrical connection with the tabs of the electrode assembly 22 to input or output electrical energy of the battery cell 20. The electrode terminals 23 may be disposed on the housing 211 of the housing 21 or on the end cap 212' of the housing 21. The electrode terminals 23 and the tabs may be directly connected, for example, by welding the electrode terminals 23 to the tabs. Alternatively, the electrode terminals 23 and the tabs may be indirectly connected, for example, by connecting the electrode terminals 23 to the tabs via a current collector 25. The current collector 25 may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0140] As an example, such as Figure 3As shown, openings 2111 are formed at opposite ends of the housing 211. There are two end caps 212' in the housing 21, one end cap 212' closing one opening 2111 of the housing 211. An electrode terminal 23 is insulatedly disposed on one end cap 212'. The electrode terminal 23 is electrically connected to one tab of the electrode assembly 22. For example, the tab and the electrode terminal 23 are indirectly connected through a current collector 24. The other end cap 212' is electrically connected to another tab of the electrode assembly 22. The other tab of the electrode assembly 22 and the end cap 212' can be indirectly connected through a current collector 25, thereby achieving electrical connection with the end cap 212'.

[0141] Please refer to Figure 4 , Figure 5 , Figure 4 This application provides a schematic diagram of the first wall 212 and the current collection member 25 assembled along the first direction X for some embodiments of the present application. Figure 5 for Figure 4 A cross-sectional view along line A1-A1 shows an embodiment of this application providing a battery cell 20. The battery cell 20 includes a housing 21, an electrode assembly 22, and a current collector 25. The housing 21 includes a first wall 212. The electrode assembly 22 is housed within the housing 21 and includes a main body 221 and a first tab 222. The first tab 222 is disposed at one end of the main body 221 facing the first wall 212 along a first direction X. The current collector 25 includes a current collector body 251 and a first protrusion 252. Along the first direction X, at least a portion of the current collector body 251 is located between the first tab 222 and the first wall 212. The current collector body 251 has a first surface 251 facing the first wall 212. 1. A first protrusion 252 is disposed on a first surface 2511. The first protrusion 252 is welded to the first wall 212. A portion of the current collecting body 251 is disposed around the outside of the first protrusion 252 and connected to the first electrode tab 222. The first protrusion 252 includes a side wall 2521 and an end wall 2522. The side wall 2521 is located between the end wall 2522 and the current collecting body 251 along a first direction X. The side wall 2521 extends circumferentially along the end wall 2522. One end of the side wall 2521 is connected to the current collecting body 251, and the other end is connected to the end wall 2522. The end wall 2522 is welded to the first wall 212. The minimum thickness of the side wall 2521 is greater than the maximum thickness of the current collecting body 251.

[0142] The first wall 212 can be the end cap 212' of the outer casing 21, or it can be part of the wall of the casing 211.

[0143] The electrode assembly 22 includes a first electrode, a second electrode, a separator, a first tab 222, and a second tab 223. The first and second electrodes have opposite polarities, with one being a positive electrode and the other a negative electrode. The separator insulatingly separates the first and second electrodes. The first tab 222 is electrically connected to the first electrode and protrudes from one end of the current collector of the first electrode. The first tab 222 can be integrally formed with the current collector of the first electrode or separately disposed and connected. The second tab 223 is electrically connected to the second electrode and protrudes from one end of the current collector of the second electrode. The second tab 223 can be integrally formed with the current collector of the second electrode or separately disposed and connected. The region corresponding to the active material layer of the first electrode, the region corresponding to the active material layer of the second electrode, and at least a portion of the separator together form the main body 221 of the electrode assembly 22.

[0144] The electrode assembly 22 can be a wound electrode assembly 22 or a stacked electrode assembly 22. The first tab 222 and the second tab 223 can be located at the same end of the main body 221 along the first direction X, which helps to reduce the size of the battery cell 20 along the first direction X and improve the energy density. The first tab 222 and the second tab 223 can be located at opposite ends of the main body 221 along the first direction X, which facilitates the electrical connection between the first tab 222 and the first wall 212 and the second tab 223 and the electrode terminal 23. Figure 3 The diagram shows the first tab 222 and the second tab 223 located at opposite ends of the main body 221 along the first direction X.

[0145] Along the first direction X, the main body 221 and the first wall 212 are located on both sides of the flow collecting body 251. In the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the first wall 212 overlaps with at least a portion of the orthographic projection of the flow collecting body 251, and at least a portion of the orthographic projection of the main body 221 overlaps with at least a portion of the orthographic projection of the flow collecting body 251.

[0146] The first tab 222 is located on the side of the current collector 251 opposite to the first wall 212. The current collector 251 is connected to the first tab 222. There are various ways to connect the current collector 251 and the first tab 222, such as welding or connecting with conductive adhesive. The current collector 251 can have various shapes, such as a rectangular structure or a disc structure. Figure 3 The diagram shows the case where the current collector 251 is a disk structure.

[0147] The first surface 2511 can be the surface of the current collector 251 facing the first wall 212 in the first direction X and being closest to the first wall 212. In some embodiments, the first surface 2511 can be the side of the current collector 251 facing the first wall 212 and having the largest area.

[0148] The first protrusion 252 protrudes from the first surface 2511. Understandably, the first protrusion 252 extends from the first surface 2511 along the direction from the main body 221 toward the first wall 212. The first protrusion 252 can be a columnar structure protruding from the first surface 2511, such as a cylindrical structure, conical structure, prism structure, pyramidal structure, etc. The first protrusion 252 can be a hollow structure, which helps to reduce the weight of the current collector 25, thereby reducing the weight of the battery cell 20 and improving the energy density of the battery cell 20. The dashed line marked P1 in the figure represents the interface between the current collector body 251 and the first protrusion 252, and is not a limitation on the structure of the current collector 25.

[0149] The current collector 251 can be partially arranged around the first protrusion 252. Understandably, the first protrusion 252 is located in the central region of the current collector 251. This allows the current collector 251 and the first tab 222 to form multiple connection points. These multiple connection points can surround the outer periphery of the first protrusion 252, which is beneficial for uniform current distribution in the current collector 251 and reduces the risk of excessive temperature rise due to excessive local current density in the current collector 251. The first protrusion 252 can also be located at the edge of the current collector 251. It should be noted that the central region of the current collector 251 is not limited to the geometric center region of the current collector 251.

[0150] The first protrusion 252 and the current collector 251 can be separately configured and connected, such as by welding or bonding. The material of the first protrusion 252 and the current collector 251 can be the same, facilitating a more stable connection. Alternatively, the materials of the first protrusion 252 and the current collector 251 can be different, allowing for the selection of suitable materials to improve the connection performance between the first protrusion 252 and the first wall 212, as well as between the current collector 251 and the first tab 222, thereby improving the electrical connection performance between the electrode assembly 22 and the first wall 212.

[0151] The first protrusion 252 includes a sidewall 2521 and an endwall 2522, with one end of the sidewall 2521 connected to the endwall 2522. The dashed line shown in Figure P2 is the boundary line between the sidewall 2521 and the endwall 2522, and should not be considered a limitation on the structure of the current-collecting member 25. The sidewall 2521 extends circumferentially along the endwall 2522, and the end of the sidewall 2521 facing away from the endwall 2522 is open, forming an open cavity together with the endwall 2522. The current-collecting body 251 can seal the open end of the cavity formed by the sidewall 2521 and the endwall 2522. Alternatively, the current-collecting body 251 can shield a portion of the open end of the cavity formed by the sidewall 2521 and the endwall 2522. For example, as shown... Figure 5 As shown, the current collector body 251 has a second surface 2512 opposite to the first surface 2511. The second surface 2512 faces the main body portion 221, and a first groove 2513 is provided on the second surface 2512 at a position corresponding to the first protrusion 252. In the direction from the electrode assembly 22 to the first wall 212, the first groove 2513 may extend beyond the first surface 2511. It can be understood that the first groove 2513 extends to the first protrusion 252, and the first protrusion 252 may be a hollow structure. In this embodiment, the first protrusion 252 includes a side wall 2521 and an end wall 2522. The side wall 2521 surrounds the end wall 2522. One end of the side wall 2521 is connected to the current collector body 251, and the other end is connected to the end wall 2522. The side wall 2521 and the end wall 2522 together form part of the first groove 2513. The inner surfaces of the sidewall 2521 and the endwall 2522 are both part of the groove wall surface 25131 of the first groove. The cavity formed by the sidewall 2521 and the endwall 2522 is open to one end of the groove of the first groove 2513 located on the second surface 2512. The cavity formed by the sidewall 2521 and the endwall 2522 is part of the first groove 2513. The other part of the first groove 2513 is located between the extension surface of the first surface 2511 and the extension surface of the second surface 2512.

[0152] The side wall 2521 and the end wall 2522 can be separately set and connected, or the side wall 2521 and the end wall 2522 can be integrally formed.

[0153] The end wall 2522 is welded to the first wall 212. Along the first direction X, the side wall 2521 is located between the current collector 251 and the end wall 2522, and connects the current collector 251 and the end wall 2522. This makes at least a portion of the side wall 2521 located on the current path between the first tab 222 and the first wall 212. The current path is the path through which the current flows.

[0154] The minimum thickness of sidewall 2521 is the minimum distance between the inner and outer surfaces of sidewall 2521. For example... Figure 5As shown, the minimum thickness of the sidewall 2521 is L1. The maximum thickness of the current collecting body 251 is L, where L < L1. The minimum thickness of the sidewall 2521 is greater than the maximum thickness of the current collecting body 251, meaning that the thickness of the sidewall 2521 at any position is greater than the maximum thickness of the current collecting body 251. Therefore, the thickness of the portion of the sidewall 2521 located in the flow path between the first tab 222 and the first wall 212 is greater than the maximum thickness of the current collecting body 251.

[0155] A portion of the current collector 251 is arranged around the outside of the first protrusion 252 and connected to the first tab 222. The end wall 2522 of the first protrusion 252 is welded to the first wall 212. The side wall 2521 is located between the current collector 251 and the end wall 2522 along the first direction X. The current of the first tab 222 of the electrode assembly 22 passes through the current collector 251 and the side wall 2521 in sequence before reaching the first wall 212. The minimum thickness of the side wall 2521 is greater than the maximum thickness of the current collector 251, which can improve the current carrying capacity of the portion of the first protrusion 252 located in the current path between the first tab 222 and the first wall 212, reduce the risk of the side wall 2521 being melted when the current flows through the first protrusion 252, improve the stability of the electrical connection between the first wall 212 and the first tab 222, and thus improve the reliability of the battery cell 20.

[0156] In some embodiments, the first protrusion 252 is welded to the first wall 212 to form a first solder mark Q1, and the minimum thickness of the area of ​​the end wall 2522 located on the outer periphery of the first solder mark Q1 is greater than the maximum thickness of the current collector body 251.

[0157] Viewed along the first direction X, a portion of the end wall 2522 is located on the outer periphery of the first solder mark Q1. At least a portion of the area of ​​the end wall 2522 located on the outer periphery of the first solder mark Q1 is located on the current path between the first tab 222 and the first wall 212. Therefore, the current of the first tab 222 of the electrode assembly 22 sequentially passes through the current collector 251, the side wall 2521, the area of ​​the end wall 2522 located on the outer periphery of the first solder mark Q1, the first solder mark Q1, and finally reaches the first wall 212. The minimum thickness of the area of ​​the end wall 2522 located on the outer periphery of the first solder mark Q1 is greater than the maximum thickness of the current collector 251; that is, the thickness of the end wall 2522 at any position on the outer periphery of the first solder mark Q1 is greater than the maximum thickness of the current collector 251. The minimum thickness of the end wall 2522 is L2, where L < L2.

[0158] By having a minimum thickness greater than the maximum thickness of the current collector body 251 in the region of the end wall 2522 of the first protrusion 252 located on the outer periphery of the first solder mark Q1, the overall current carrying capacity of the first protrusion 252 can be improved, further reducing the risk of the first protrusion 252 being melted when current flows through it, further improving the stability of the electrical connection between the first wall 212 and the first tab 222, thereby further improving the reliability of the battery cell 20.

[0159] In other embodiments, the end wall 2522 does not have a region surrounding the outer periphery of the first solder mark Q1 (e.g. Figure 11 (As shown). In this case, in the direction perpendicular to the first direction X, a portion of the first solder mark Q1 is located on the end wall 2522, and another portion of the first solder mark Q1 is located on the first wall 212. In this embodiment, in the direction perpendicular to the first direction X, the minimum thickness of the region of the end wall 2522 located inside the first solder mark Q1 can be greater than the maximum thickness of the current collector 251, and the thickness of the region of the end wall 2522 located inside the first solder mark Q1 can be less than the thickness of the current collector 251.

[0160] like Figure 6 As shown, Figure 6 This is a schematic diagram of the structure of a current collector 25 having a second solder mark Q2, provided in some embodiments of this application. In some embodiments, the current collector body 251 is welded to the first tab 222 to form the second solder mark Q2; the second solder mark Q2 is disposed around the first protrusion 252.

[0161] The second solder mark Q2 is disposed around the first protrusion 252, and understandably, the second solder mark Q2 extends 360° circumferentially along the first protrusion 252.

[0162] The current collector 251 is welded to the first tab 222 to form a second solder mark Q2, which facilitates the electrical connection between the current collector 251 and the first tab 222 and ensures good stability of the electrical connection. The second solder mark Q2 is arranged around the first protrusion 252, resulting in a larger connection area between the first tab 222 and the current collector 251, which is beneficial to improving the current carrying capacity.

[0163] like Figure 7 As shown, Figure 7 This is a schematic diagram of a current collector 25 with a second solder mark provided for other embodiments of this application. In other embodiments, there are multiple second solder mark portions Q2, which are spaced apart circumferentially along the first protrusion 252.

[0164] The second solder mark Q2 can be an elongated strip extending in a direction perpendicular to the first direction X. Along the extension direction of the second solder mark Q2, one end of the second solder mark Q2 can extend to the outer edge of the current collector body 251, and the other end of the second solder mark Q2 can be at a distance from the first protrusion 252, so that the projected area of ​​the second solder mark Q2 in the first direction X is larger. This is beneficial to improving the current flow capacity between the first electrode 222 and the current collector 25, and can also reduce the risk of welding energy damaging the first protrusion 252 during the welding process.

[0165] Of course, in other embodiments, along the extending direction of the second solder mark Q2, one end of the second solder mark Q2 is at a distance from the outer edge of the current collector body 251, and the other end of the second solder mark Q2 may be at a distance from the first protrusion 252.

[0166] The multiple second solder marks Q2 can be arranged at uniform intervals along the circumference of the first protrusion 252, or they can be arranged at non-uniform intervals. The number of second solder marks Q2 can be two, three, or more. Figure 7 The diagram shows a configuration where there are three second solder marks Q2, and these three second solder marks Q2 are evenly spaced along the circumference of the first protrusion 252.

[0167] There are multiple second solder marks Q2, which are spaced apart along the circumference of the first protrusion 252. Along the circumference of the first protrusion 252, the space between two adjacent second solder marks Q2 provides space for electrolyte flow and gas discharge inside the electrode assembly 22. This is beneficial to improving the wetting efficiency and performance of the electrode assembly 22, as well as facilitating the external venting of the electrode assembly 22, reducing the risk of accidents such as explosion and fire, and improving the reliability of the battery cell 20.

[0168] There are various welding methods for the current collector 251 and the first tab 222, such as laser welding and ultrasonic welding. In some embodiments, the second surface 2512 of the current collector 251 is connected to the surface of the second solder mark Q2. Before welding, the current collector 251 has a welding area, and the portion of the second surface 2512 located in the welding area contacts the first tab 222. Then, the current collector 251 and the first tab 222 are welded in the welding area by a welding device, and a portion of the second solder mark Q2 is located in the welding area.

[0169] like Figure 8 , Figure 9 As shown, Figure 8 This is an isometric view of the current collection member 25 provided in some embodiments of this application. Figure 9 for Figure 8In the enlarged view at B1, in some embodiments, the first surface 2511 is provided with a second groove 2514. The bottom wall of the second groove 2514 is welded to the first tab 222. The second groove 2514 is recessed from the first surface 2511 in a direction pointing from the first surface 2511 to the second surface 2512. A second protrusion 2515 is formed on the current collector body 251 at a position corresponding to the second groove 2514, protruding from the second surface 2512. The second protrusion 2515 includes the bottom wall of the second groove 2514, so that the bottom wall of the second groove 2514 can abut against the first tab 222, reducing the risk of poor soldering between the current collector body 251 and the first tab 222, and improving the welding quality of the first tab 222 and the current collector 25. A portion of the second solder mark Q2 may be located within the second groove 2514. The dashed line shown at P3 in the figure is the boundary between the second protrusion 2515 and the second surface 2512.

[0170] like Figure 4 , Figure 5 As shown, the first wall 212 can be located on the side of the first protrusion 252 away from the current collecting body 251, and the first wall 212 and the first protrusion 252 are welded together.

[0171] like Figure 10 , Figure 11 As shown, Figure 10 This is a schematic diagram of the first wall 212 and the current collection member 25 assembled along the first direction X, provided in another embodiment of this application. Figure 11 for Figure 10 A cross-sectional view along line A2-A2. In some other embodiments, the first wall 212 is provided with a through hole 2121, the through hole 2121 penetrates the first wall 212, at least a portion of the first protrusion 252 passes through the through hole 2121, and is welded to the first wall 212 to form a first solder mark Q1.

[0172] The through-hole 2121 penetrates the first wall 212, meaning that the through-hole 2121 penetrates both sides of the first wall 212 in its thickness direction. The thickness direction of the first wall 212 can be parallel to the first direction X. Understandably, the two ends of the through-hole 2121 are located on two opposite surfaces of the first wall 212 in its thickness direction. The first wall 212 has an inner surface (inner surface 2122) and an outer surface (outer surface 2123) opposite to each other along the first direction X. The inner surface 2122 of the first wall faces the main body 221. The inner surface 2122 of the first wall can be the surface of the first wall 212 facing the main body 221 in the first direction X and closest to the main body 221. In some embodiments, the inner surface 2122 of the first wall can be the surface of the first wall 21211 facing the main body 221 with the largest area. The outer surface 2123 of the first wall can be the surface of the first wall 212 facing away from the main body 221 in the first direction X and furthest from the main body 221. In some embodiments, the outer surface 2123 of the first wall may be the surface with the largest area on the side of the first wall 212 away from the main body 221. One end of the through hole 2121 extends to the inner surface 2122 of the first wall, and the other end of the through hole 2121 extends to the outer surface 2123 of the first wall.

[0173] The through hole 2121 can be any hole with the same cross-sectional area along the first direction X, facilitating manufacturing. The through hole 2121 can also be any hole with different cross-sectional areas along the first direction X, such as a stepped hole. The through hole 2121 can have various shapes, such as circular, rectangular, or triangular holes. The shape of the outer contour of the cross-section of the through hole 2121 can match the shape of the outer contour of the cross-section of the sidewall 2521. Both the cross-section of the through hole 2121 and the cross-section of the sidewall 2521 are perpendicular to the first direction X.

[0174] The first protrusion 252 is inserted through the through hole 2121. The first protrusion 252 can be completely located inside the through hole 2121, or the first protrusion 252 can be partially located inside the through hole 2121.

[0175] The first protrusion 252 and the first wall 212 can be connected by ultrasonic welding, laser welding, etc. The first solder mark Q1 can extend circumferentially along the through hole 2121. Along the radial direction of the first through hole 2121, one end of the first solder mark Q1 is connected to the first wall 212, and the other end of the first solder mark Q1 is connected to the first protrusion 252. The radial direction of the first through hole 2121 can be any direction perpendicular to the first direction X.

[0176] A through hole 2121 is provided in the first wall 212. At least a portion of the first protrusion 252 passes through the through hole 2121 of the first wall 212 and is welded to the first wall 212 to form a first weld mark Q1. Welding can be performed from the outside of the first wall 212, and the welding status of the first protrusion 252 and the first wall 212 is visible during the welding process, allowing for real-time assessment of the welding status and making the connection more convenient. The first protrusion 252, passing through the through hole 2121 of the first wall 212, also serves a positioning function, improving the stability of the connection between the first wall 212 and the first protrusion 252.

[0177] like Figure 11 As shown, in some embodiments, the first wall 212 has an inner surface facing the main body 221, and one end of the through hole 2121 extends to the inner surface 2122 of the first wall, which is closer to the main body 221 than the first solder mark Q1.

[0178] Along the first direction X, the inner surface 2122 of the first wall is closer to the main body 221 than the first solder mark Q1. Understandably, along the first direction X, the first solder mark Q1 does not extend to the inner surface 2122 of the first wall or the first solder mark Q1 extends to a position flush with the inner surface 2122 of the first wall.

[0179] One end of the through hole 2121 extends to the inner surface of the first wall surface 21211 towards the main body 221. The inner surface 2122 of the first wall is closer to the main body 221 than the first solder mark Q1. Therefore, the first solder mark Q1 does not extend to the inner surface or does not extend to a position flush with the inner surface 2122 of the first wall. This makes a part of the first wall 212 located on the side of the first solder mark Q1 facing the electrode assembly 22, reducing the risk of leakage at or near the first solder mark Q1 and improving the reliability of the battery cell 20.

[0180] like Figure 11 As shown, in some embodiments, along the first direction X, the minimum distance between the first solder mark Q1 and the inner surface 2122 of the first wall is H, where 0.5mm≤H≤1.5mm.

[0181] H is the distance between the position of the first solder mark Q1 closest to the main body 221 along the first direction X and the inner surface 2122 of the first wall. For example, H can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0182] By ensuring that H is greater than or equal to 0.5 mm, the portion of the first wall 212 located on the side of the first solder mark Q1 facing the electrode assembly 22 is larger, reducing the risk of leakage from the first wall 212 or the first solder mark Q1 and improving the reliability of the battery cell 20. By ensuring that H is less than or equal to 1.5 mm, the portion of the first wall located on the side of the first solder mark Q1 facing the electrode assembly 22 is not too large, which is beneficial for the first solder mark Q1 to have a larger size in the first direction X, improving the welding strength of the first wall 212 and the first protrusion 252, thereby giving the battery cell 20 better reliability. Therefore, 0.5 mm ≤ H ≤ 1.5 mm can reduce the risk of leakage of the battery cell 20 and improve the welding strength of the first wall 212 and the first protrusion 252, thereby giving the battery cell 20 higher reliability.

[0183] In some embodiments, 0.8mm ≤ H ≤ 1mm.

[0184] For example, H can be 0.8mm, 0.82mm, 0.85mm, 0.88mm, 0.91mm, 0.92mm, 0.95mm, 0.98mm, 1mm, etc.

[0185] By ensuring that H is greater than or equal to 0.8 mm, the portion of the first wall 212 located on the side of the first solder mark Q1 facing the electrode assembly 22 is larger, which can further reduce the risk of leakage from the first wall 212 or the first solder mark Q1, and further improve the reliability of the battery cell 20. By ensuring that H is less than or equal to 1 mm, the portion of the first wall located on the side of the first solder mark Q1 facing the electrode assembly 22 is not too large, which is beneficial for the first solder mark Q1 to have a larger size in the first direction X, further improving the welding strength of the first wall 212 and the first protrusion 252, thereby making the battery cell 20 have better reliability. Therefore, 0.8 mm ≤ H ≤ 1 mm can further reduce the risk of leakage of the battery cell 20 and improve the welding strength of the first wall 212 and the first protrusion 252, thereby making the battery cell 20 have higher reliability.

[0186] like Figure 12 , Figure 13 As shown, Figure 12 This is a schematic diagram of the first wall 212 and the current collection member 25 before assembly, provided in some embodiments of this application. Figure 13 for Figure 12 A cross-sectional view of the first wall 212 and the current collecting member 25 after assembly. In some embodiments, the hole wall of the through hole 2121 includes a first wall surface 21211 and a chamfered surface 21212 arranged along the first direction X. The chamfered surface 21212 connects the first wall surface 21211 and the inner surface 2122 of the first wall. One end of the first wall surface 21211 away from the chamfered surface 21212 is connected to the surface of the first solder mark Q1.

[0187] The first wall surface 21211 is arranged around the axis of the through hole 2121, and the intersection line of the plane passing through the axis of the through hole 2121 and parallel to the first direction X with the first wall surface 21211 is parallel to the first direction X.

[0188] The chamfered surface 21212 is arranged around the axis of the through hole 2121, and is connected to the end of the first wall surface 21211 away from the first solder mark Q1 along the first direction X. The chamfered surface 21212 can be an arc surface. Understandably, the intersection line (generatrix of the chamfered surface 21212) of the plane passing through the axis of the through hole 2121 and parallel to the first direction X and the chamfered surface 21212 is an arc. The chamfered surface 21212 can also be a conical surface. Understandably, the intersection line (generatrix of the chamfered surface 21212) of the plane passing through the axis of the through hole 2121 and parallel to the first direction X and the chamfered surface 21212 is an inclined surface. The intersection line of the plane passing through the axis of the through hole 2121 and parallel to the first direction X and the chamfered surface 21212 is arranged at an angle to the first direction X. Understandably, the chamfered surface 21212 is inclined relative to the first wall surface 21211.

[0189] The chamfered surface 21212 reduces the risk of sharp corners appearing at the junction of the first wall surface 21211 and the inner surface 2122 of the first wall, which could damage other structures during assembly.

[0190] The surface of the first solder mark Q1 is connected to the chamfered surface 21212 through the first wall surface 21211. That is, a part of the first wall 212 is located on the side of the first solder mark Q1 facing the main body 221. During the welding process, the first wall 212 is not welded through.

[0191] Therefore, when the hole wall of the through hole 2121 includes a chamfered surface 21212 connected to the inner surface 2122 of the first wall, the chamfered surface 21212 and the first solder mark Q1 are connected through the first hole wall. Thus, the first solder mark Q1 does not extend to the chamfered surface 21212, thereby preventing the first solder mark Q1 from extending to the inner surface or to a position flush with the inner surface. This results in a portion of the first wall 212 being located on the side of the first solder mark Q1 facing the electrode assembly 22, reducing the risk of leakage at or near the first solder mark Q1, and improving the reliability of the battery cell 20.

[0192] like Figure 14 , Figure 15 As shown, Figure 14 This is a diagram showing the first wall 212, the current collection member 25, and the shielding member 30 assembled along the first direction X, according to some embodiments of this application. Figure 15 for Figure 14A cross-sectional view along line A3-A3. In some embodiments, the first wall 212 is provided with a shielding member 30, which is located on the side of the first solder mark Q1 away from the main body 221. Along the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the shielding member 30 overlaps with at least a portion of the orthographic projection of the first solder mark Q1.

[0193] The shielding member 30 may contact the first solder mark Q1, for example, by adhering to the surface of the first solder mark Q1 facing away from the electrode assembly 22. Alternatively, the shielding member 30 may be connected to the first solder mark Q1, for example, by bonding the shielding member 30 to the surface of the first solder mark Q1 facing away from the electrode assembly 22. The shielding member 30 may also not contact the surface of the first solder mark Q1 facing away from the electrode assembly 22, for example, by separating the shielding member 30 from the first solder mark Q1 through a portion of the first wall 212 or a portion of the first protrusion 252, or there may be a gap between the shielding member 30 and the first solder mark Q1.

[0194] The shielding member 30 can be connected to the first wall 212 to improve its stability. For example, the shielding member 30 can be welded to the first wall 212, bonded, or connected by bolts or other fasteners.

[0195] The shielding component 30 can be made of metal, such as aluminum, copper, or stainless steel. It can also be made of non-metal, such as rubber.

[0196] By positioning the shielding member 30 on the side of the first solder mark Q1 away from the main body 221, and ensuring that at least a portion of the orthographic projection of the shielding member 30 overlaps with at least a portion of the orthographic projection of the first solder mark Q1 in a projection plane perpendicular to the first direction X, the shielding member 30 can protect the first solder mark Q1, reduce the risk of the first solder mark Q1 being damaged by external forces, thereby reducing the risk of welding failure of the first wall 212 and the second region, and thus improving the reliability of the battery cell 20.

[0197] like Figure 15 As shown, in some embodiments, the shielding member 30 can be completely located outside the through hole 2121, which facilitates the connection between the shielding member 30 and the first wall 212.

[0198] like Figure 16 , Figure 17 As shown, Figure 16 A diagram showing the first wall 212, the current collection member 25, and the shielding member 30 assembled along the first direction X, as provided in other embodiments of this application. Figure 17 for Figure 16 A cross-sectional view along line A4-A4. In some other embodiments, at least a portion of the shield 30 is located within the through hole 2121.

[0199] If the shielding member 30 is partially located inside the through hole 2121, then part of the shielding member 30 and the first wall 212 share a space in the first direction X, which can reduce the space occupied by the shielding member 30 outside the housing 21 and reduce the volume of the battery cell 20.

[0200] If the shielding member 30 can be completely located inside the through hole 2121, then the shielding member 30 and the first wall 212 will share the space in the first direction X, which can prevent the shielding member 30 from occupying the space outside the housing 21 and reduce the volume of the battery cell 20.

[0201] By having at least a portion of the shield 30 located within the through hole 2121, the space occupied by the shield 30 on the outside of the housing 21 is reduced or avoided, thereby reducing the volume of the battery cell 20.

[0202] Please continue to refer to Figure 15 , Figure 17 In some embodiments, the shielding member 30 can block the through hole 2121, thereby sealing the through hole 2121 and reducing the risk of leakage.

[0203] like Figures 18-20 As shown, Figure 18 A cross-sectional view of the first wall 212, the current collection member 25, and the shielding member 30 assembled according to some embodiments of this application. Figure 19 for Figure 18 A schematic diagram of the unassembled edge of the first wall 212, the flow collecting component 25, and the shielding component 30. Figure 20 for Figure 18 Enlarged view at B2. In some embodiments, the through hole 2121 includes a first hole segment 21213 and a second hole segment 21214 along a first direction X. The first hole segment 21213 is further away from the main body 221 than the second hole segment 21214. The hole wall surface of the first hole segment 21213 and the hole wall surface of the second hole segment 21214 are connected by a first stepped surface 21215. The cross-sectional area of ​​the first hole segment 21213 is larger than the cross-sectional area of ​​the second hole segment 21214. At least a portion of the first protrusion 252 is located in the second hole segment 21214. The cross-sections of the first hole segment 21213 and the cross-sections of the second hole segment 21214 are both perpendicular to the first direction X. At least a portion of the shielding member 30 is accommodated in the first hole segment 21213 and abuts against the first stepped surface 21215.

[0204] The wall surface of the first hole segment 21213 and the wall surface of the second hole segment 21214 are connected by a first stepped surface 21215, thus the through hole 2121 is a stepped hole. In some embodiments, the first hole segment 21213 and the second hole segment 21214 may be partial segments of the through hole 2121. For example... Figure 13As shown, the first hole segment 21213 and the second hole segment 21214 can also jointly form a through hole 2121. The end of the first hole segment 21213 away from the second hole segment 21214 extends to the outer surface 2123 of the first wall, and the end of the second hole segment 21214 away from the first hole segment 21213 extends to the inner surface 2122 of the first wall. The aforementioned first wall surface 21211 and chamfered surface 21212 can be part of the hole wall surface of the second hole segment 21214.

[0205] The cross-sectional area of ​​the first hole segment 21213 can be the area of ​​the region enclosed by the intersection of the hole wall surface of the first hole segment 21213 and the plane perpendicular to the first direction X. The shape of the first hole segment 21213 can be circular, rectangular, conical, etc. Of course, the first hole segment 21213 can also be a combination of hole segments of various shapes. For example, the part of the first hole segment 21213 near the second hole segment 21214 is a circular hole segment, and the part of the first hole segment 21213 away from the second hole segment 21214 is a conical hole segment.

[0206] The cross-sectional area of ​​the second hole segment 21214 can be the area enclosed by the intersection of the hole wall surface of the second hole segment 21214 and the plane perpendicular to the first direction X. The shape of the second hole segment 21214 can be circular, rectangular, conical, etc. Of course, the second hole segment 21214 can also be a combination of hole segments of various shapes. For example, the part of the second hole segment 21214 near the first hole segment 21213 is a circular hole segment, and the part of the second hole segment 21214 away from the first hole segment 21213 is a conical hole segment.

[0207] The cross-sections of the first hole segment 21213 and the second hole segment 21214 are both perpendicular to the first direction X.

[0208] For example, such as Figures 18-20 As shown, the first hole segment 21213 is a conical hole segment. The large end of the first hole segment 21213 extends to the outer surface 2123 of the first wall, and the small end of the first hole segment 21213 is connected to the outer edge of the first stepped surface 21215, facilitating the entry of welding tools into the through hole 2121 to weld the first wall 212 and the first protrusion 252. The second hole segment 21214 is a combination of a conical hole segment and a cylindrical hole segment. The large end of the conical hole segment of the second hole segment 21214 extends to the inner surface 2122 of the first wall, and the small end of the conical hole segment of the second hole segment 21214 is connected to one end of the cylindrical hole segment of the second hole segment 21214. The other end of the cylindrical hole segment of the second hole segment 21214 is connected to the surface of the first solder mark Q1. The wall surface of the conical hole section of the second hole section 21214 can be the aforementioned chamfered surface 21212, and the wall surface of the cylindrical hole section of the second hole section 21214 can be the aforementioned first wall surface 21211.

[0209] like Figure 19As shown, in some embodiments, the diameter of the cylindrical hole segment of the second hole segment 21214 is D1, where 4mm ≤ D1 ≤ 10mm. Exemplarily, D1 can be 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc.

[0210] By ensuring that D1 is greater than or equal to 4mm, the first protrusion 252 can easily pass through the through hole 2121, and the first protrusion 252 can also have a larger cross-sectional area, facilitating the welding connection between the first wall 212 and the first protrusion 252. By ensuring that D1 is less than or equal to 10mm, the space of the through hole 2121 is not too large, reducing the impact of the through hole 2121 on the strength of the first wall 212, thus giving the first wall 212 better strength. Therefore, 4mm≤D1≤10mm not only facilitates the welding connection between the first wall 212 and the first protrusion 252, but also ensures that the first wall 212 has good strength.

[0211] The first protrusion 252 can be located only within the second hole section 21214, which can reduce the space occupied by the first protrusion 252, reduce the weight of the current collecting member 25, and also make the space of the through hole 2121 not occupied by the first protrusion 252 larger, which facilitates the welding equipment to enter the through hole 2121 to weld the first wall 212 and the first protrusion 252.

[0212] The first protrusion 252 can also be located partly in the second hole section 21214 and the other part extends into the first hole section 21213, so that the first protrusion 252 can be closer to the outside of the outer shell 21, which facilitates welding the first wall 212 and the first protrusion 252.

[0213] Along the direction from the electrode assembly 22 to the first wall 212, the first protrusion 252 may extend beyond the outer surface 2123 of the first wall, or it may not extend beyond the outer surface of the first protrusion 252. For example... Figure 12 As shown, the first protrusion 252 has a first end face 2526 away from the current collecting body 251. Along the direction from the electrode assembly 22 towards the first wall 212, the first end face 2526 is closer to the main body 221 than the outer surface 2123 of the first wall. A space is formed between the first end face 2526 and the extended surface of the outer surface 2123 of the first wall. At least a portion of the blocking member 30 can be located within this space, allowing at least a portion of the blocking member 30 to be located within the first hole segment 21213. The blocking member 30 can be completely located within the first hole segment 21213, or it can be partially located within the first hole segment 21213.

[0214] The shielding member 30 abuts against the first step surface 21215. This can be either that the shielding member 30 is in contact with the first step surface 21215 but not connected, or that the shielding member 30 is connected to the first step surface 21215.

[0215] By having at least a portion of the shielding member 30 accommodated within the first hole segment 21213, the space occupied by the shielding member 30 on the outside of the housing 21 is reduced or avoided, thereby reducing the volume of the battery cell 20. The shielding member 30 abuts against the first stepped surface 21215, facilitating its installation. Furthermore, the first stepped surface 21215 can limit the shielding member 30, preventing it from moving further into the through hole 2121 and improving its stability.

[0216] like Figures 18-20 As shown, in some embodiments, a portion of the first protrusion 252 is accommodated in the first hole segment 21213, and the shielding member 30 is provided with a relief groove 31 on the side facing the first step surface 21215. The end of the first protrusion 252 away from the current collecting body 251 extends to the relief groove 31.

[0217] The clearance groove 31 is formed by recessing from the surface of the shielding member 30 facing the first step surface 21215 in a direction away from the first step surface 21215. The clearance groove 31 can be completely located within the first hole section 21213, or it can be partially located within the first hole section 21213 and partially located within the second hole section 21214. Of course, the clearance groove 31 can also be partially located outside the through hole 2121. In embodiments where the shielding member 30 is provided with the clearance groove 31, the first protrusion 252 can extend into the first hole section 21213.

[0218] By providing a clearance groove 31 on the side of the shielding member 30 facing the first step surface 21215, and extending the end of the first protrusion 252 away from the current collecting body 251 to the clearance groove 31, it is convenient to set the first protrusion 252 and the shielding member 30, and reduce the risk of interference between the shielding member 30 and the first protrusion 252.

[0219] like Figure 20As shown, in some embodiments, the through hole 2121 includes a first hole segment 21213 and a second hole segment 21214. Along the first direction X, the first hole segment 21213 is further away from the main body 221 than the second hole segment 21214. The hole wall surface of the first hole segment 21213 and the hole wall surface of the second hole segment 21214 are connected by a first stepped surface 21215. The cross-sectional area of ​​the first hole segment 21213 is larger than the cross-sectional area of ​​the second hole segment 21214. At least part of the first protrusion 252... Located in the second hole section 21214, the first wall 212 has opposing inner and outer surfaces, with the inner surface facing the main body 221. One end of the through hole 2121 extends to the inner surface, and the other end of the through hole 2121 extends to the outer surface 2123 of the first wall. A portion of the first solder mark Q1 extends from the first step surface 21215 along the outer surface 2123 of the first wall toward the inner surface 2122 of the first wall, and the other portion of the first solder mark Q1 is accommodated in the first hole section 21213.

[0220] Along the first direction X, a portion of the first solder mark Q1 is located on the side of the first step surface 21215 near the main body 221, and another portion of the first solder mark Q1 protrudes from the first step surface 21215 and is located within the first hole section 21213.

[0221] A portion of the first solder mark Q1 extends from the first step surface 21215 along the outer surface 2123 of the first wall toward the inner surface 2122 of the first wall, while another portion of the first solder mark Q1 is accommodated in the first hole section 21213. This reduces the risk of the first solder mark Q1 protruding from the outer surface 2123 of the first wall, reduces the risk of the first solder mark Q1 being damaged by external forces, and avoids or reduces the space occupied by the first solder mark Q1 on the outside of the housing 21, thereby reducing the size of the battery cell 20.

[0222] like Figures 21-24 As shown, Figure 21 This is a schematic diagram of the first wall 212, the current collection member 25, and the shielding member 30 assembled along the first direction X, as provided in some further embodiments of this application. Figure 22 for Figure 21 Sectional view along line A5-A5. Figure 23 for Figure 22 Enlarged view at B3 in the middle. Figure 24 for Figure 21 A schematic diagram of the first wall 212, the current collecting member 25, and the shielding member 30 before assembly. In some embodiments, the first protrusion 252 abuts against the first wall 212, such that a first gap M is formed between the first surface 2511 and the inner surface 2122 of the first wall.

[0223] With the first protrusion 252 abutting against the first wall 212, a portion of the first protrusion 252 is located between the inner surface 2122 and the first surface 2511 of the first wall. A first gap M is provided around the first protrusion 252.

[0224] The first protrusion 252 abuts against the first wall 212, forming a first gap M between the first surface 2511 and the first wall 212. The electrode assembly 22 can exhaust gas through the first gap M, which can improve exhaust efficiency and facilitate timely pressure relief of the battery cell 20, reduce the risk of explosion, fire and other problems, and improve the reliability of the battery cell 20.

[0225] Please continue to refer to Figures 21-24 In some embodiments, the first protrusion 252 includes a first portion 2523 and a second portion 2524. The first portion 2523 is closer to the current collecting body 251 than the second portion 2524. The cross-sectional area of ​​the first portion 2523 is larger than the cross-sectional area of ​​the second portion 2524. The cross-sections of the first portion 2523 and the second portion 2524 are both perpendicular to the first direction X. At least a portion of the second portion 2524 is inserted into the through hole 2121. Along the first direction X, the first portion 2523 abuts against the first wall 212.

[0226] The first part 2523 is located at the end opposite to the current collection body 251, which is the second end face 25231, and the first wall 212 abuts against the second end face 25231.

[0227] The cross-sectional area of ​​the first portion 2523 is larger than that of the second portion 2524, and the first portion 2523 abuts against the first wall 212 to form a first gap M. Therefore, the first portion 2523 has better strength and can stably support the first wall 212, thereby forming a stable first gap M between the first wall 212 and the first surface 2511. This also helps to improve the connection stability between the first wall 212 and the second region, thus improving the reliability of the battery cell 20. Since the cross-sectional area of ​​the first portion 2523 is larger than that of the second portion 2524, and the first portion 2523 is located on the current path, it helps to improve the current carrying capacity of the second region, reducing the risk of the second region being melted on the current path when the electrode assembly 22 converges current to the first wall 212, and improving the reliability of the battery cell 20.

[0228] In some embodiments, the first protrusion 252 further includes a transition portion 2525, which connects the first portion 2523 and the second portion 2524. The outer peripheral surface of the transition portion 2525 connects the outer peripheral surface of the second portion 2524 and the second end face 25231. The second end face 25231 and the outer peripheral surface of the transition portion 2525 both abut against the first wall 212.

[0229] In embodiments where the wall surface of the through hole 2121 includes a first wall surface 21211 and a chamfered surface 21212, the chamfered surface 21212 can fit against the outer peripheral surface of the transition portion 2525, thereby achieving that the outer peripheral surface of the transition portion 2525 abuts against the first wall 212. The outer peripheral surface of the transition portion 2525 can be a surface that can match and fit against the chamfered surface 21212.

[0230] The outer peripheral surface of the transition portion 2525 abuts against the first wall 212, and the first portion 2523 abuts against the first wall 212. This facilitates the formation of a stable first gap M between the first wall 212 and the first surface 2511, and also improves the connection stability between the first wall 212 and the second region, thereby improving the reliability of the battery cell 20. The dashed line marked P4 in the figure is the boundary line between the first portion 2523 and the transition portion 2525, and the dashed line marked P5 is the boundary line between the transition portion 2525 and the second portion 2524. These lines should not be taken as limitations on the structure of the current collector 25.

[0231] In an embodiment where the first protrusion 252 includes an end wall 2522 and a side wall 2521, the first portion 2523 may be at least a portion of the side wall 2521, and the second portion 2524 may be at least a portion of the end wall 2522.

[0232] like Figure 21 , Figure 22 , Figure 24 As shown, in some embodiments, the first wall 212 is also provided with a pressure relief mechanism 40, and the first gap M leads to the pressure relief mechanism 40.

[0233] The pressure relief mechanism 40 can be a component such as an explosion-proof valve, an explosion-proof disc, a gas valve, or a pressure relief valve.

[0234] By allowing the first gap M to pass through the pressure relief mechanism 40, it is convenient for the inside of the outer casing 21 to vent through the first gap M to the pressure relief mechanism 40, which facilitates timely pressure relief of the battery cell 20, reduces the risk of explosion, fire and other problems, and improves the reliability of the battery cell 20.

[0235] like Figure 21 , Figure 22 , Figure 24 As shown, in some embodiments, the orthographic projection of the pressure relief mechanism 40 does not overlap with the orthographic projection of the first protrusion 252 in the projection plane perpendicular to the first direction X.

[0236] Specifically, in the projection plane perpendicular to the first direction X, the orthographic projection of the pressure relief mechanism 40 does not overlap with the orthographic projection of the first protrusion 252.

[0237] The orthographic projection of the pressure relief mechanism 40 does not overlap with the orthographic projection of the first protrusion 252, reducing the risk that the first protrusion 252 will interfere with the exhaust of the battery cell 20 through the first gap M to the pressure relief mechanism 40. This facilitates timely pressure relief of the battery cell 20, reduces the risk of explosion, fire and other problems, and improves the reliability of the battery cell 20.

[0238] like Figures 25-27 As shown, Figure 25 This is a schematic diagram of the first wall 212, the current collection member 25, and the shielding member 30 assembled along the first direction X, provided in some embodiments of this application. Figure 26 for Figure 25 Sectional view along line A6-A6, Figure 27 for Figure 26 Enlarged view at B4. In some embodiments, the edge of the current collecting body 251 is provided with an edge portion 253, which protrudes from the first surface 2511. A second gap N is formed between the edge portion 253 and the first wall 212. Along the first direction X, the size of the second gap N is H1, where 0.2mm≤H1≤1mm.

[0239] Specifically, a second gap N is formed between the edge portion 253 and the inner surface 2122 of the first wall.

[0240] The edge portion 253 can be located in the region of the collecting body 251 near the edge of the collecting member 25, or the edge portion 253 can be located at the edge of the collecting body 251, or the edge portion 253 can be located at the collecting body 251 and flush with the edge of the collecting body 251. This arrangement can make the distance between the first protrusion 252 and the edge portion 253 larger, which can further alleviate the problem of the first gap M being blocked after the collecting body 251 is deformed.

[0241] The edge portion 253 is separately disposed from and connected to the current collecting body 251, for example, by welding or bonding. The edge portion 253 can be connected to the edge of the current collecting body 251 and protrude from the first surface 2511, or the edge portion 253 can be connected to the first surface 2511 and located close to the edge of the current collecting body 251. The edge portion 253 and the current collecting body 251 can be made of the same material or different materials.

[0242] The edge portion 253 and the current collection body 251 can also be integrally formed, reducing the manufacturing difficulty of the current collection component 25 and increasing the strength of the current collection component 25. For example, as... Figure 28 , Figure 29 As shown, Figure 28 An isometric view of the current collection member 25 provided in some embodiments of this application. Figure 29 for Figure 28The enlarged view at B5 shows that the edge portion 253 can be a rolled edge structure disposed on the outer edge of the collector body 251. The edge portion 253 includes a first edge portion 2531 and a second edge portion 2532. The first edge portion 2531 is connected to the collector body 251 and protrudes from the first surface 2511. The second edge portion 2532 is connected to the end of the first edge portion 2531 away from the collector body 251 in the first direction X, and the second edge portion 2532 extends towards the first protrusion 252. The edge portion 253 is a rolled edge structure disposed on the outer edge of the collector body 251, which facilitates the manufacturing and shaping of the edge portion 253.

[0243] There can be one or more edge portions 253. In embodiments with multiple edge portions 253, the multiple edge portions 253 can be arranged at circumferential intervals along the collection body 251. It should be noted that H1 is merely a symbol representing the distance between the edge portion 253 and the inner surface 2122 of the first wall, and does not mean that the distance between each edge portion 253 and the inner surface 2122 of the first wall is the same. It can be understood that the distance between any edge portion 253 and the inner surface 2122 of the first wall satisfies 0.2mm to 1mm.

[0244] For example, H1 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0245] A second gap N is formed between the edge portion 253 and the first wall 212. This second gap N facilitates the outward venting of air from the electrode assembly 22, improving venting efficiency and allowing for timely pressure relief of the battery cell 20. This reduces the risk of explosions and fires, thus improving the reliability of the battery cell 20. The second gap N also provides space for the current collector body 251 to deform towards the first wall 212. In the event of abnormal internal pressure in the battery cell 20, the deformation of the current collector body 251 can alleviate the problem. After the current collector 25 deforms, the edge portion 253 can abut against the inner surface 2122 of the first wall, ensuring that a first gap M is always present between the inner surface and the first surface 2511. This reduces the risk of the first gap M being blocked due to deformation of the current collector body 251 or the absence of the first gap M between the first surface 2511 and the inner surface, thereby reducing the risk of explosions and fires caused by internal pressure buildup in the battery cell 20 and improving its reliability. By ensuring that H1 is greater than or equal to 0.2 mm, the second gap N is made larger in the first direction X, providing a larger venting space between the edge 253 and the inner surface. This improves venting efficiency and facilitates timely pressure relief of the battery cell 20, reducing the risk of explosions and fires, and enhancing the reliability of the battery cell 20. It also provides a larger space for the current collector 251 to deform towards the first wall 212. In the event of abnormal internal pressure in the battery cell 20, the deformation of the current collector 251 can effectively alleviate the problem. By ensuring that H1 is less than or equal to 1 mm, the size of the second gap N in the first direction X is not too large, which helps to reduce the size of the battery cell 20 in the first direction X and improve the energy density of the battery cell 20. Therefore, 0.2 mm ≤ H1 ≤ 1 mm ensures that the battery cell 20 has good reliability and energy density.

[0246] Please continue to refer to Figure 27 In some embodiments, the edge portion 253 protrudes from the first surface 2511 by a dimension of H2 along the first direction X, where 1mm≤H2≤4mm.

[0247] H2 can be the distance between the end of the edge portion 253 away from the current collecting body 251 and the first surface 2511 along the first direction X.

[0248] H2 is merely a symbol representing the distance between the edge portion 253 and the first surface 2511, and does not mean that the distance between each edge portion 253 and the first surface 2511 is the same. Understandably, the distance between any edge portion 253 and the first surface 2511 satisfies 1mm to 4mm.

[0249] For example, H2 can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, etc.

[0250] By ensuring that H2 is greater than or equal to 1 mm, the edge portion 253 protrudes a larger size from the first surface 2511, which is beneficial for the edge portion 253 to have higher strength and facilitates the edge portion 253 to abut against the first wall 212 to maintain the stability of the first gap M, thereby improving the reliability of the battery cell 20. H2 is less than or equal to 4 mm, which prevents the size of the edge portion 253 from being too large, reducing the space occupied by the edge portion 253, thereby helping to reduce the volume of the battery cell 20 and provide the energy density of the battery cell 20. Therefore, 1 mm ≤ H2 ≤ 4 mm, which enables the battery cell 20 to have higher reliability and energy density.

[0251] like Figure 30 , Figure 31 As shown, Figure 30 A cross-sectional view of the first wall 212, the current collection member 25, and the shielding member 30 assembled according to some further embodiments of this application. Figure 31 This is an isometric view of the current collector 25 provided in some embodiments of this application. In some embodiments, the current collector body 251 is further provided with an exhaust port 2516, which penetrates both sides of the current collector body 251 along the first direction X and communicates with the first gap M. A first region is also provided with an exhaust port 2516, which penetrates both sides of the current collector body 251 and communicates with the first gap M. Gas on the side of the current collector body 251 facing the electrode assembly 22 can enter the first gap M through the exhaust port 2516 and be discharged from the first gap M to the pressure relief mechanism 40. This shortens the exhaust path, facilitates timely pressure relief of the battery cell 20, reduces the risk of explosions, fires, and other problems, and improves the reliability of the battery cell 20.

[0252] The number of vent holes 2516 can be one or more. In embodiments with multiple vent holes 2516, the multiple vent holes 2516 can be spaced apart around the first protrusion 252. The multiple vent holes 2516 spaced apart around the first protrusion 252 can increase the rate at which the current collector body 251 vents towards the first gap M from the side facing the electrode assembly 22, facilitating timely pressure relief of the battery cell 20, reducing the risk of explosion, fire, and other problems, and improving the reliability of the battery cell 20.

[0253] The vent hole 2516 can have various shapes, such as a circular hole, a rectangular hole, or an elongated hole. In some embodiments, the diameter of the vent hole 2516 is D2, where 1mm ≤ D2 ≤ 4mm.

[0254] For example, D2 can be 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, etc.

[0255] With D2 greater than or equal to 1mm, the exhaust rate can be increased, facilitating timely pressure relief and improving the reliability of the battery cell 20. With D2 less than or equal to 4mm, the problem of reduced strength of the current collector body 251 caused by setting the exhaust hole 2516 is alleviated, which is conducive to the current collector component 25 having better strength and the reliability of the electrical connection between the electrode assembly 22 and the first wall 212. Therefore, 1mm≤D2≤4mm makes the battery cell 20 have better reliability.

[0256] This application also provides a battery device 100, which includes the battery cell 20 provided in any of the above embodiments.

[0257] The battery cell 20 provided in any of the above embodiments has good reliability, and the battery device 100 including the battery cell 20 also has good reliability.

[0258] This application also provides an electrical device, which includes the battery cell 20 or the battery device 100 provided in any of the above embodiments.

[0259] The reliability of the battery cell 20 and the battery device 100 provided in the above embodiments are both good, and the power supply device powered by the battery cell 20 or the battery device 100 also has good power supply reliability.

[0260] This application provides a cylindrical battery, which includes a casing 21 and an electrode assembly 22, with the electrode assembly 22 housed within the casing 21. The electrode assembly 22 includes a main body 221, a first tab 222, and a second tab 223, with the first tab 222 and the second tab 223 protruding from opposite ends of the main body 221 along a first direction X. The casing 21 includes a first wall 212 with a through hole 2121 penetrating both sides of the first wall 212 along the first direction X. Specifically, it includes a casing 211 and two end caps 212'. Along the first direction X, the casing 211 has openings 2111 at both ends, and the two end caps 212' respectively cover the two openings 2111. One end cap 212' is insulated with an electrode terminal 23, which is electrically connected to the second electrode tab 223. The other end cap 212' is connected to the first electrode tab 222 through a current collector 25. The end cap 212' connected to the first electrode tab 222 through the current collector 25 is the first wall 212. The current collecting member 25 includes a current collecting body 251 and a first protrusion 252. At least a portion of the current collecting body 251 is located between the first electrode tab 222 and the first wall 212 along the first direction X. The current collecting body 251 is connected to the first electrode tab 222. The current collecting body 251 has a first surface 2511 facing the first wall 212. The first protrusion 252 is disposed on the first surface 2511, passes through a through hole 2121, and is welded to the first wall 212 to form a first solder mark Q1. The first wall 212 has an inner surface facing the main body 221. One end of the through hole 2121 extends to the inner surface 2122 of the first wall. The inner surface 2122 of the first wall is closer to the main body 221 than the first solder mark Q1. Along the first direction X, the minimum distance between the first solder mark Q1 and the inner surface is H, where 0.5mm ≤ H ≤ 1.5mm.

[0261] The through hole 2121 includes a first hole segment 21213 and a second hole segment 21214. Along the first direction X, the first hole segment 21213 is further away from the main body 221 than the second hole segment 21214. The cross-sectional area of ​​the first hole segment 21213 is larger than the cross-sectional area of ​​the second hole segment 21214. The hole wall surface of the first hole segment 21213 and the hole wall surface of the second hole segment 21214 are connected by a first stepped surface 21215. The end of the first hole segment 21213 away from the second hole segment 21214 extends to the outer surface 2123 of the first wall, and the end of the second hole segment 21214 away from the first hole segment 21213 extends to the inner surface 2122 of the first wall. The hole wall of the second hole segment 21214 includes a first wall surface 21211 and a chamfered surface 21212 arranged along the first direction X. The chamfered surface 21212 connects the first wall surface 21211 and the inner surface 2122 of the first wall. One end of the first wall surface 21211 away from the chamfered surface 21212 is connected to the surface of the first solder mark Q1. A portion of the first protrusion 252 is located in the second hole segment 21214, and another portion of the first protrusion 252 extends to the first hole segment 21213. The end face of the first protrusion 252 away from the current collector body 251 is closer to the main body 221 than the outer surface 2123 of the first wall. The first wall 212 is provided with a shielding member 30. The shielding member 30 is located on the side of the first solder mark Q1 away from the main body 221 and is completely located in the first hole segment 21213. Along the projection plane perpendicular to the first direction X, a portion of the orthographic projection of the shielding member 30 overlaps with the orthographic projection of the first solder mark Q1. The shielding member 30 has a relief groove 31 on the side facing the first step surface 21215, and the portion of the first protrusion 252 extending to the first hole section 21213 is located in the relief groove 31.

[0262] The first protrusion 252 includes a sidewall 2521 and an endwall 2522. The sidewall 2521 extends circumferentially along the endwall 2522. One end of the sidewall 2521 is connected to the current collector body 251, and the other end is connected to the endwall 2522. At least one of the sidewall 2521 and the endwall 2522 is connected to the first solder mark Q1. The minimum thickness of the sidewall 2521 is greater than the maximum thickness of the current collector body 251.

[0263] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0264] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, include: The outer shell, including the first wall; An electrode assembly is housed within the housing. The electrode assembly includes a main body and a first electrode tab, wherein the first electrode tab is disposed at one end of the main body facing the first wall along a first direction. A current collecting component includes a current collecting body and a first protrusion. Along the first direction, at least a portion of the current collecting body is located between the first electrode tab and the first wall. The current collecting body has a first surface facing the first wall. The first protrusion is disposed on the first surface and welded to the first wall. A portion of the current collecting body is disposed around the outside of the first protrusion and connected to the first electrode tab. The first protrusion includes a sidewall and an endwall. The sidewall extends circumferentially along the endwall and is located between the endwall and the current collecting body along the first direction. One end of the sidewall is connected to the current collecting body and the other end is connected to the endwall. The endwall is welded to the first wall. The minimum thickness of the sidewall is greater than the maximum thickness of the current collecting body.

2. The battery cell of claim 1, wherein, The first protrusion is welded to the first wall to form a first weld mark, and the minimum thickness of the end wall located on the outer periphery of the first weld mark is greater than the maximum thickness of the current collector body.

3. The battery cell of claim 1, wherein, The current collector body is welded to the first electrode tab to form a second solder mark; The second solder mark is disposed around the first protrusion, or there are multiple second solder marks, which are spaced apart circumferentially along the first protrusion.

4. The battery cell of any one of claims 1-3, wherein, The first wall is provided with a through hole, the through hole penetrates the first wall, at least a portion of the first protrusion passes through the through hole and is welded to the first wall to form a first weld mark portion.

5. The battery cell of claim 4, wherein the cathode comprises a lithium metal oxide. The first wall has an inner surface facing the main body, one end of the through hole extends to the inner surface, and the inner surface is closer to the main body than the first solder mark.

6. The battery cell of claim 5, wherein, Along the first direction, the minimum distance between the first solder mark and the inner surface is H, where 0.5mm≤H≤1.5mm; optionally, 0.8mm≤H≤1mm.

7. The battery cell of claim 5, wherein the cathode comprises a lithium metal oxide. The hole wall includes a first wall surface and a chamfered surface arranged along the first direction. The chamfered surface connects the first wall surface and the inner surface. The end of the first wall surface away from the chamfered surface is connected to the surface of the first solder mark.

8. The battery cell as described in claim 4, characterized in that, The first wall is provided with a shielding member, which is located on the side of the first solder mark portion away from the main body portion. In a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the shielding member overlaps with at least a portion of the orthographic projection of the first solder mark portion. At least a portion of the shield is located within the through hole.

9. The battery cell as described in claim 8, characterized in that, The through hole includes a first hole segment and a second hole segment. Along the first direction, the first hole segment is further away from the main body than the second hole segment. The hole wall surface of the first hole segment and the hole wall surface of the second hole segment are connected by a first step surface. The cross-sectional area of ​​the first hole segment is larger than the cross-sectional area of ​​the second hole segment. At least a portion of the first protrusion is located in the second hole segment. The cross-section is perpendicular to the first direction. At least a portion of the shield is accommodated in the first hole and abuts against the first stepped surface.

10. The battery cell as described in claim 9, characterized in that, A portion of the first protrusion is accommodated in the first hole section, and the side of the shield facing the first step surface is provided with a clearance groove, and the end of the first protrusion away from the current collecting body extends to the clearance groove.

11. The battery cell as described in claim 5, characterized in that, The through hole includes a first segment and a second segment. Along the first direction, the first segment is further away from the main body than the second segment. The wall surface of the first segment and the wall surface of the second segment are connected by a first stepped surface. The cross-sectional area of ​​the first segment is larger than that of the second segment. At least a portion of the first protrusion is located in the second segment. The first wall has opposing inner and outer surfaces. The inner surface faces the main body. One end of the through hole extends to the inner surface, and the other end extends to the outer surface. A portion of the first solder mark extends from the first stepped surface in a direction from the outer surface toward the inner surface. Another portion of the first solder mark is accommodated in the first segment.

12. The battery cell according to any one of claims 1-3, characterized in that, The first protrusion abuts against the first wall, thereby forming a first gap between the first surface and the first wall.

13. The battery cell according to any one of claims 1-3, characterized in that, The edge of the current collecting body is provided with an edge portion, which protrudes from the first surface and forms a second gap between the edge portion and the first wall. Along the first direction, the size of the second gap is H1, where 0.2mm≤H1≤1mm.

14. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-13.

15. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-13 or a battery device as described in claim 14.

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