Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment, an electrode assembly of the battery cell comprises a first pole piece, the first pole piece comprises a first main body and a first tab, the first main body comprises a first active material layer, the first main body has a first end face and a second end face which are opposite in the width direction of the first pole piece, the first tab is connected to the first end face, and the second tab is connected to the second end face. One end of the first active substance layer extends to the second end surface, the first main body is provided with two opposite third end surfaces along the length direction of the first pole piece, and two ends of the first active substance layer respectively extend to the two third end surfaces; at least one of the two third end faces is connected with the second end face through the chamfered face, so that the sharp degree of sharp corners between the second end face and the third end faces can be reduced. The risk of short circuit failure caused by the fact that a sharp corner between the second end face and the third end face pierces the isolating membrane in the falling mechanical test process of the battery cell and when the battery cell is in the falling working condition is reduced, the safety of the battery cell falling mechanical test is improved, and the qualified rate of the battery cell falling test is increased.

Description

Technical Field

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

[0002] With the rapid development of new energy technologies, battery cells have been widely used in electronic devices, electric vehicles, electric two-wheelers, power tools, and other fields. As the application of battery cells becomes more widespread, higher requirements are being placed on their safety. Summary of the Invention

[0003] This application provides a battery cell and an electrical device to improve the safety performance of the battery cell.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including an electrode assembly, the electrode assembly including a first electrode sheet, the first electrode sheet including a first body and a first tab, the first body including a first active material layer, the first body having opposing first end faces and second end faces along the width direction of the first electrode sheet, the first tab being connected to the first end face, one end of the first active material layer extending to the second end face, and the first body having opposing third end faces along the length direction of the first electrode sheet, the two ends of the first active material layer extending to the two third end faces respectively; wherein, at least one of the two third end faces is connected to the second end face through a chamfered surface.

[0005] In one or more of the above optional embodiments, at least one of the two third end faces is connected to the second end face via a chamfered surface. This reduces the sharpness of the corners between the second and third end faces, lowering the risk of these corners piercing the separator. This reduces the risk of short-circuit failure during drop testing due to the corners piercing the separator, improving the safety and pass rate of the drop test. Furthermore, the chamfered surface connection between at least one of the two third end faces also reduces the risk of short circuits caused by the corners piercing the separator during drop testing, further enhancing the battery's safety performance.

[0006] In some embodiments of the first aspect of this application, the chamfered surface includes at least one bevel.

[0007] In one or more of the above optional embodiments, the chamfered surface includes at least one bevel, which not only helps to reduce the sharpness between the second end face and the third end face, but also makes the chamfered surface easier to form, facilitating the cell manufacturing process.

[0008] In some embodiments of the first aspect of this application, the chamfered surface includes a bevel, a first rounded surface and a second rounded surface, the bevel is connected to the second end face through the first rounded surface, and the bevel is connected to the third end face through the second rounded surface.

[0009] In one or more of the above optional embodiments, the inclined surface and the second end face are connected by a first rounded corner surface, and the inclined surface and the third end face are connected by a second rounded corner surface. This avoids the formation of sharp corners between the inclined surface and the second end face, as well as between the inclined surface and the third end face, reducing the risk of sharp corners piercing the separator. It also reduces the risk of short circuit in the battery cell caused by sharp corners between the second and third end faces piercing the separator, thereby improving the safety performance of the battery cell in drop mechanical testing, increasing the pass rate of the battery cell drop test, and enhancing the safety performance of the battery cell under drop conditions.

[0010] In some embodiments of the first aspect of this application, the chamfered surface includes a plurality of the inclined surfaces, and two adjacent inclined surfaces are set at an obtuse angle.

[0011] In one or more of the above optional embodiments, the chamfered surface includes multiple bevels, that is, multiple chamfering processes are performed between the second end face and the third end face to further reduce the sharpness of the corner between the second end face and the third end face, further reduce the risk of the corner piercing the separator and causing a short circuit, thereby further improving the safety performance of the battery cell drop mechanical test, increasing the battery cell drop test pass rate and the safety performance of the battery cell under drop conditions.

[0012] In some embodiments of the first aspect of this application, the chamfered surface further includes a first rounded surface and a second rounded surface, one of the chamfered surfaces is connected to the second end face through the first rounded surface, and the other chamfered surface is connected to the third end face through the second rounded surface.

[0013] In one or more of the above optional embodiments, one inclined surface is connected to the second end face through a first rounded corner surface, and one inclined surface is connected to the third end face through a second rounded corner surface. This avoids the formation of sharp corners between the inclined surface and the second end face, as well as between the inclined surface and the third end face, reducing the risk of sharp corners piercing the separator. It also reduces the risk of short circuit in the battery cell caused by sharp corners between the second and third end faces piercing the separator, thereby improving the safety performance of the battery cell in drop mechanical testing, increasing the pass rate of the battery cell drop test, and enhancing the safety performance of the battery cell under drop conditions.

[0014] In some embodiments of the first aspect of this application, the chamfered surface further includes a third rounded corner surface, and two adjacent chamfered surfaces are connected through the third rounded corner surface.

[0015] In one or more of the above optional embodiments, two adjacent inclined surfaces are connected by a third rounded corner surface to avoid the formation of sharp corners between adjacent inclined surfaces, reduce the risk of short circuit of the battery cell caused by the sharp corner between the second end face and the third end face piercing the isolation membrane, improve the safety performance of battery cell drop mechanical test, increase the pass rate of battery cell drop test and the safety performance of battery cell under drop conditions.

[0016] In some embodiments of the first aspect of this application, the radius of the first rounded corner is R1, the radius of the second rounded corner is R2, the radius of the third rounded corner is R3, 0.6≤R3 / R1≤1.5, and 0.6≤R3 / R2≤1.5.

[0017] In one or more of the above optional embodiments, by limiting the ratio of the radius of the third rounded corner surface to the radius of the first rounded corner surface to 0.6≤R3 / R1≤1.5, the difference between the radius of the third rounded corner surface and the radius of the first rounded corner surface can be controlled within a reasonable range, so that the difference between the radius of the third rounded corner surface and the radius of the first rounded corner surface is not too large or too small. This reduces the risk of tearing due to uneven stress on the first electrode during the charging and discharging process of the battery cell caused by the difference between the radius of the first rounded corner surface and the radius of the third rounded corner surface being too large or too small, thereby improving the safety performance of the battery cell. By limiting the ratio of the radius of the third rounded corner to the radius of the second rounded corner to 0.6≤R3 / R2≤1.5, the difference between the radius of the third rounded corner and the radius of the second rounded corner can be controlled within a reasonable range. This ensures that the difference between the radius of the third rounded corner and the radius of the second rounded corner is not too large or too small, reducing the risk of tearing due to uneven stress on the first electrode during the charging and discharging process caused by the difference between the radius of the second rounded corner and the radius of the third rounded corner being too large or too small, thereby improving the safety performance of the battery cell.

[0018] In some embodiments of the first aspect of this application, the radius of the first rounded corner is R1, the radius of the second rounded corner is R2, and the radius of the third rounded corner is R3, where 0.2mm≤R1≤3mm, 0.2mm≤R2≤3mm, and 0.2mm≤R3≤3mm.

[0019] In one or more of the above optional embodiments, R1 ≥ 0.2mm helps reduce the processing difficulty of the first rounded corner surface, improving the manufacturability and practicality of the battery cell. R2 ≥ 0.2mm helps reduce the processing difficulty of the second rounded corner surface, improving the manufacturability and practicality of the battery cell. R3 ≥ 0.2mm helps reduce the processing difficulty of the third rounded corner surface, improving the manufacturability and practicality of the battery cell. R1 ≤ 3mm reduces the energy density loss caused by processing the first rounded corner surface. R2 ≤ 3mm reduces the energy density loss caused by processing the second rounded corner surface. R3 ≤ 3mm reduces the energy density loss caused by processing the third rounded corner surface.

[0020] In some embodiments of the first aspect of this application, the angle between the inclined surface and the second end face is greater than or equal to 151° and less than or equal to 178°.

[0021] In one or more of the above optional embodiments, the angle between the inclined surface and the second end face is greater than or equal to 151°, which reduces the sharpness of the included angle between the inclined surface and the second end face. This reduces the risk of short-circuit failure caused by the included angle between the second end face and the third end face piercing the separator during drop mechanical testing, thereby improving the safety of the battery cell during drop mechanical testing, increasing the pass rate of the battery cell during drop testing, and improving the safety performance of the battery cell. An angle between the inclined surface and the second end face is less than or equal to 178°, which reduces processing difficulty and improves the manufacturability of the battery cell.

[0022] In some embodiments of the first aspect of this application, the angle between the inclined surface and the second end face is greater than or equal to 160° and less than or equal to 170°.

[0023] In one or more of the above optional embodiments, the angle between the inclined surface and the second end face is greater than or equal to 160°, making the included angle between the inclined surface and the second end face less sharp. This further reduces the risk of short-circuit failure caused by the included angle between the second end face and the third end face piercing the separator during drop mechanical testing, thereby improving the safety of the battery cell during drop mechanical testing, increasing the pass rate of the battery cell drop test, and improving the safety performance of the battery cell. An angle between the inclined surface and the second end face is less than or equal to 170°, further reducing processing difficulty and improving the manufacturability of the battery cell.

[0024] In some embodiments of the first aspect of this application, the chamfered surface includes a plurality of the inclined surfaces, and two adjacent inclined surfaces are set at an obtuse angle; the ratio of the supplementary angle between the angle of the one of the two adjacent inclined surfaces closer to the third end face and the second end face to the supplementary angle between the angle of the one of the two adjacent inclined surfaces closer to the second end face and the second end face is greater than or equal to 1.05 and less than or equal to 1.5.

[0025] In one or more of the above optional embodiments, the ratio of the supplementary angle between the angle of the one closer to the third end face and the second end face of two adjacent inclined planes to the supplementary angle between the angle of the one closer to the second end face and the second end face of two adjacent inclined planes is greater than or equal to 1.05. This reduces the processing difficulty of the cutter, facilitates variable cutting, thereby reducing the processing difficulty of the first electrode sheet and improving the manufacturability of the battery cell. The ratio of the supplementary angle between the one closer to the third end face and the second end face of two adjacent inclined planes to the supplementary angle between the angle of the one closer to the second end face and the second end face of two adjacent inclined planes to the supplementary angle between the angle of the two inclined planes to the second end face is less than or equal to 1.5. This reduces the sharpness of the angle between the inclined plane and the second end face, lowers the risk of short-circuit failure caused by the angle piercing the separator, improves the safety of the battery cell drop test, increases the pass rate of the battery cell drop test, and also reduces the risk of short circuit caused by the sharp angle between the inclined plane and the second end face piercing the separator when the battery cell is under drop conditions, thus improving the safety performance of the battery cell.

[0026] In some embodiments of the first aspect of this application, the ratio of the supplementary angle between the angle of the one closer to the third end face among two adjacent inclined planes and the second end face to the supplementary angle between the angle of the one closer to the second end face among two adjacent inclined planes and the second end face is greater than or equal to 1.1 and less than or equal to 1.3.

[0027] In one or more of the above optional embodiments, the ratio of the supplementary angle between the angle of the one closer to the third end face and the second end face of two adjacent inclined planes to the supplementary angle between the angle of the one closer to the second end face and the second end face of two adjacent inclined planes is greater than or equal to 1.1. This further reduces the processing difficulty of the cutter, facilitates variable cutting, and thus further reduces the processing difficulty of the first electrode sheet, further improving the manufacturability of the battery cell. The ratio of the supplementary angle between the one closer to the third end face and the second end face of two adjacent inclined planes to the supplementary angle between the angle of the one closer to the second end face and the second end face of two adjacent inclined planes to the supplementary angle between the angle of the two inclined planes to the second end face is less than or equal to 1.3. This further reduces the sharpness of the angle between the inclined plane and the second end face, further reducing the risk of short-circuit failure caused by the sharp angle between the inclined plane and the second end face piercing the separator, further improving the safety of the battery cell during drop testing and increasing the pass rate of the drop test. It also reduces the risk of short circuit in the battery cell caused by the sharp angle between the inclined plane and the second end face piercing the separator when the battery cell is under drop conditions, improving the safety performance of the battery cell.

[0028] In some embodiments of the first aspect of this application, the number of inclined planes is less than or equal to 3.

[0029] In one or more of the above optional embodiments, the number of bevels is less than or equal to 3, which alleviates the problem that too many bevel cuts during the manufacturing process cause interference during the operation of the winding tool, thereby making it impossible to guarantee the cutting accuracy.

[0030] In some embodiments of the first aspect of this application, the chamfered surface intersects the third end face at a first position along the width direction of the first electrode sheet, and the distance between the first position and the second end face is L1, where 1mm≤L1≤5mm.

[0031] In one or more of the above optional embodiments, L1≥1mm reduces the risk of debris generated during chamfering being easily entangled into the battery cell and reduces the difficulty of chamfering; L1≤5mm reduces the capacity loss caused by processing the chamfered surface, thereby reducing energy density loss and ensuring product competitiveness.

[0032] In some embodiments of the first aspect of this application, 2mm ≤ L1 ≤ 3.5mm.

[0033] In one or more of the above optional embodiments, L1≥2mm further reduces the risk of debris generated during chamfering being easily entangled into the battery cell and further reduces the difficulty of chamfering; L1≤3.5mm further reduces the capacity loss caused by processing the chamfered surface, thereby further reducing energy density loss and ensuring product competitiveness.

[0034] In some embodiments of the first aspect of this application, the chamfered surface intersects the third end face at a first position along the width direction of the first electrode, the distance between the first position and the second end face is L1, and the size of the first active material layer is L, 0.01≤L1 / L≤0.2.

[0035] In one or more of the above optional embodiments, L1 / L≥0.01 reduces the difficulty of multi-segment cutting and reduces cell yield loss when the chamfered surface is multi-segmented. L1 / L≤0.2 reduces energy density loss during chamfering and ensures high product competitiveness.

[0036] In some embodiments of the first aspect of this application, 0.03 ≤ L1 / L ≤ 0.1.

[0037] In one or more of the above optional embodiments, L1 / L≥0.03, when the chamfered surface is multi-segmented, can further reduce the difficulty of multi-segment cutting and processing, thereby reducing cell yield loss. L1 / L≤0.1 further reduces energy density loss when processing the chamfered surface, ensuring higher product competitiveness.

[0038] In some embodiments of the first aspect of this application, each of the third end faces is connected to the second end face via a chamfered surface.

[0039] In one or more of the above optional embodiments, each third end face is connected to the second end face via a chamfered surface. The sharpness of the corners between the second end face and each third end face is relatively small, reducing the risk of the sharp corners piercing the separator. This reduces the risk of short circuit failure during drop testing due to the sharp corners piercing the separator, thus improving the safety and pass rate of the drop test. The chamfered surface connection between each third end face and the second end face further reduces the risk of short circuit during drop testing due to the sharp corners piercing the separator, improving the safety performance of the battery cell.

[0040] In some embodiments of the first aspect of this application, the electrode assembly is a wound structure, the first electrode is a positive electrode, one of the two third end faces is the winding end of the first electrode along the winding direction of the electrode assembly, the other of the two third end faces is the winding start end of the first electrode, and the winding end is connected to the second end face through a chamfered surface.

[0041] In one or more of the above optional embodiments, the first electrode is a positive electrode. The winding end of the positive electrode is connected to the second end face through a chamfered surface. This reduces the sharpness of the corner between the second and third end faces, thereby lowering the risk of the sharp corner piercing the separator and causing a short circuit failure in the battery cell after the electrode assembly expands to contact the outer casing, thus improving the safety performance of the battery cell. The chamfered surface connecting the winding end of the positive electrode to the second end face also reduces the risk of short circuit failure during drop testing due to the sharp corner piercing the separator, improving the safety and pass rate of the drop test. Furthermore, the chamfered surface further reduces the risk of short circuit when the battery cell is in a drop condition due to the sharp corner piercing the separator, improving the safety performance of the battery cell.

[0042] In some embodiments of the first aspect of this application, the battery cell is a cylindrical battery cell.

[0043] In one or more of the above optional embodiments, the battery cell is a cylindrical battery cell. By connecting at least one of the third end faces of the first electrode of the cylindrical battery cell to the second end face through a chamfered surface, the sharpness of the corner between the second and third end faces can be reduced, lowering the risk of the corner piercing the separator. This reduces the risk of short-circuit failure due to the corner piercing the separator during drop testing, improving the safety and pass rate of the cylindrical battery cell in drop testing. Connecting at least one of the two third end faces to the second end face through a chamfered surface further reduces the risk of short circuit due to the corner piercing the separator during drop testing, improving the safety performance of the cylindrical battery cell.

[0044] Secondly, embodiments of this application provide an electrical device including the battery cell provided in any of the above embodiments.

[0045] In one or more of the above optional embodiments, the battery cell provided by any of the above embodiments has good safety, which is beneficial to improving the electrical safety of electrical equipment powered by the battery cell. Attached Figure Description

[0046] 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.

[0047] Figure 1 An exploded view of a cylindrical battery cell provided in an embodiment of this application;

[0048] Figure 2 This is a schematic diagram of the structure of the electrode assembly provided in the embodiments of this application;

[0049] Figure 3 This is a schematic diagram of the structure of the first electrode provided in some embodiments of this application;

[0050] Figure 4 This is a schematic diagram of the structure of the first electrode provided in other embodiments of this application;

[0051] Figure 5 This is a schematic diagram of the structure of the first electrode provided in some embodiments of this application;

[0052] Figure 6 This application provides a schematic diagram of the structure of a first electrode sheet in some of its embodiments.

[0053] Figure 7A schematic diagram of the structure of the first electrode provided in some other embodiments of this application;

[0054] Figure 8 This application provides a schematic diagram of the structure of a first electrode sheet in some further embodiments;

[0055] Figure 9 A schematic diagram of the structure of the first electrode provided in some further embodiments of this application;

[0056] Figure 10 A schematic diagram of the structure of the first electrode provided in some other embodiments of this application;

[0057] Figure 11 Schematic diagram of the structure of the first electrode provided in some other embodiments of this application;

[0058] Figure 12 Schematic diagram of the structure of the first electrode provided in some other embodiments of this application;

[0059] Figure 13 This is a schematic diagram of the structure of the first electrode provided in some other embodiments of this application.

[0060] Icons: 100-cell; 10-casing; 11-shell; 12-cover; 20-electrode assembly; 21-first electrode; 211-first body; 2111-first active material layer; 2112-first current collector; 21121-first region; 21122-second region; 212-first tab; 2121-fourth end face; 2122-fifth end face; 2113-first end face; 2114-second end face; 211 5 - Third end face; 2115' - Winding end; 2115” - Winding start end; 2116 - Chamfered surface; 21161 - Inclined surface; 21162 - First rounded corner surface; 21163 - Second rounded corner surface; 211164 - Third rounded corner surface; 22 - Second electrode; 23 - Separator; X - Width direction of the first electrode; Y - Length direction of the first electrode; Z - Thickness direction of the first electrode; K - Winding direction; Q1 - First position. Detailed Implementation

[0061] 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 and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0062] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0064] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0065] In the description of the embodiments of this application, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on this application. Furthermore, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0066] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," and "connect" 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. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0067] Currently, judging from market trends, the application of battery cells is becoming increasingly widespread. Battery cells are widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in power tools, drones, energy storage devices, and many other fields. As the application areas of battery cells continue to expand, the market demand is also constantly increasing, and the requirements for battery cell safety are becoming increasingly stringent.

[0068] The electrode assembly of a battery cell includes a positive electrode and a negative electrode. Along the length of the positive electrode, the opposite ends of the positive electrode are the cutting positions during the positive electrode manufacturing process. Similarly, along the length of the negative electrode, the opposite ends of the negative electrode are the cutting positions during the negative electrode manufacturing process. The positive electrode and the cutting positions of the positive electrode form right-angled sharp corners on their respective end faces in the width direction and at their respective end faces. These right-angled sharp corners can easily puncture the separator, leading to short-circuit failure of the battery cell. This risk is even greater during drop tests and when the battery cell is under drop conditions, thus reducing the safety performance of the battery cell.

[0069] Based on the above considerations, in order to alleviate the problem of reduced cell safety caused by the sharp right angles formed by the electrode end face and the end face in the width direction of the electrode piercing the separator, the present application provides a cell including an electrode assembly. The electrode assembly includes a first electrode, the first electrode includes a first body and a first tab, the first body includes a first active material layer, the first body has a first end face and a second end face opposite to each other along the width direction of the first electrode, the first tab is connected to the first end face, one end of the first active material layer extends to the second end face, and the first body has two opposite third end faces along the length direction of the first electrode, the two ends of the first active material layer respectively extend to the two third end faces; wherein, at least one of the two third end faces is connected to the second end face through a chamfered surface.

[0070] At least one of the two third end faces is connected to the second end face via a chamfered surface. This reduces the sharpness of the corners between the second and third end faces, lowering the risk of these corners piercing the separator. This reduces the risk of short-circuit failure during drop testing due to the corners piercing the separator, thus improving the safety and pass rate of the drop test. Furthermore, the chamfered surface connection also reduces the risk of short circuits caused by the corners piercing the separator during drop testing, further enhancing the cell's safety performance.

[0071] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical equipment such as electric two-wheelers, power tools, drones, and energy storage devices. The battery cells conforming to the operating conditions of this application can also be used as the power supply system for electrical equipment, which helps improve the safety performance of the battery cells.

[0072] This application provides an electrical device that uses battery cells as a power source. The electrical device can be, but is not limited to, electronic devices, power tools, electric vehicles, drones, and energy storage devices. Electronic devices can include mobile phones, tablets, laptops, etc.; power tools can include electric drills, chainsaws, etc.; and electric vehicles can include electric cars, electric motorcycles, electric bicycles, etc.

[0073] like Figure 1 , Figure 2 As shown, this application provides a battery cell 100, which includes a housing 10 and an electrode assembly 20; the electrode assembly 20 is housed within the housing 10.

[0074] The outer casing 10 forms a receiving space. The receiving space can be used to house the electrode assembly 20, electrolyte, etc. The outer casing 10 can be a rigid shell 11, such as a steel shell or an aluminum shell, forming a steel shell battery cell or an aluminum shell battery cell. The outer casing 10 can also be formed of a softer material, such as an aluminum-plastic film or a steel-plastic film, forming a pouch battery cell.

[0075] like Figure 1 As shown, the outer shell 10 may include a shell 11 and a cover 12. The shell 11 is a hollow structure with an opening at least one end, and the cover 12 is used to cover the opening of the shell 11 so that the cover 12 and the shell 11 together form an outer shell 10 with a receiving space.

[0076] The electrode assembly 20 includes a first electrode 21, a second electrode 22, and a separator 23. The first electrode 21 and the second electrode 22 have opposite polarities, that is, one of the first electrode 21 and the second electrode 22 is the positive electrode, and the other of the first electrode 21 and the second electrode 22 is the negative electrode.

[0077] The positive electrode includes a positive current collector and a positive active material layer, with the positive active material layer disposed on at least one side of the positive current collector. For lithium-ion cells, the positive current collector can be made of aluminum. The positive active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The positive current collector can be a composite current collector or a non-composite current collector.

[0078] The negative electrode includes a negative current collector and a negative active material layer, with the negative active material layer disposed on at least one side of the negative current collector. For lithium-ion cells, the material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. The negative current collector can be a composite current collector or a non-composite current collector.

[0079] The separator 23 is used to insulate and separate the first electrode 21 and the second electrode 22, reducing the risk of short circuit in the cell 100. The material of the separator 23 may include PP (polypropylene) or PE (polyethylene), etc.

[0080] The electrode assembly 20 can be a stacked structure or a wound structure.

[0081] In embodiments where the electrode assembly 20 has a stacked structure, the first electrode 21, the separator 23, and the second electrode 22 are stacked in a certain order more than once.

[0082] In embodiments where the electrode assembly 20 has a wound structure, the first electrode 21, the separator 23, the second electrode 22, and another separator 23 are stacked in a certain order and then wound to form a wound electrode assembly; or, the separator 23, the first electrode 21, the other separator 23, and the second electrode 22 are stacked in a certain order and then wound to form a wound electrode assembly. The wound electrode assembly can be a flat wound electrode assembly or a cylindrical electrode assembly.

[0083] In embodiments where the electrode assembly 20 has a cylindrical structure, the battery cell 100 can be a cylindrical battery cell 100. By connecting at least one of the third end faces 2115 of the first electrode 21 of the cylindrical battery cell 100 to the second end face 2114 via a chamfered surface 2116, the sharpness of the angle between the second end face 2114 and the third end face 2115 can be reduced, lowering the risk of the sharp angle piercing the separator 23. This reduces the risk of short-circuit failure of the cylindrical battery cell 100 during drop testing due to the sharp angle piercing the separator 23, thereby improving the safety and drop test pass rate of the cylindrical battery cell 100. At least one of the two third end faces 2115 is connected to the second end face 2114 through a chamfered surface 2116, which can reduce the risk of short circuit of the cylindrical cell 100 caused by the sharp corner between the second end face 2114 and the third end face 2115 piercing the isolation membrane 23 when the cylindrical cell 100 is in a drop condition, thereby improving the safety performance of the cylindrical cell 100. Figure 1 The image shows the case where cell 100 is a cylindrical cell 100. Figure 2 The diagram shows the case where the electrode assembly 20 has a cylindrical structure.

[0084] like Figure 3 , Figure 4As shown, in some embodiments, the first electrode 21 includes a first body 211 and a first tab 212, and the first body 211 includes a first active material layer 2111.

[0085] The first body 211 includes a first current collector 2112 and a first active material layer 2111. Along the thickness direction Z of the first electrode, the first current collector 2112 has the first active material layer 2111 on at least one side.

[0086] Along the width direction X of the first electrode, the first active material layer 2111 extends to the second end face 2114. Understandably, along the width direction X of the first electrode, one end of the first active material layer 2111 and one end of the first current collector 2112 are flush together to form the second end face 2114 of the first body 211.

[0087] Along the length direction Y of the first electrode, the two ends of the first active material layer 2111 extend to two third end faces 2115 respectively. Understandably, along the length direction Y of the first electrode, the two opposite end faces of the first active material layer 2111 are flush with the two opposite end faces of the first current collector 2112, thereby forming two opposite third end faces 2115 of the first body 211 at both ends along the length direction Y of the first electrode.

[0088] In embodiments where the first electrode 21 is a positive electrode, the first active material layer 2111 is a positive active material layer, and the first current collector 2112 is a positive current collector. The first current collector 2112 and the first active material layer 2111 together form the first body 211 of the first electrode 21. Along the length direction Y of the first electrode, the two opposite end faces of the first active material layer 2111 are flush with the two opposite end faces of the first current collector 2112, thereby forming two opposite third end faces 2115 at both ends along the length direction Y of the first electrode.

[0089] like Figure 3As shown, in some embodiments, along the width direction X of the first electrode, the first current collector 2112 includes a first region 21121 covered by a first active material layer 2111 and a second region 21122 not covered by the first active material layer, the first region 21121 and the second region 21122 being connected. Along the width direction X of the first electrode, a first tab 212 is connected to one end of the second region 21122 opposite to the first region 21121. This end of the second region 21122 opposite to the first region 21121 forms a first end face 2113 of the first body 211 along the width direction X of the first electrode. The end of the second region 21122 opposite to the first region 21121 and the end of the first active material layer 2111 opposite to the first region 21121 are flush together, forming a second end face 2114 of the first body 211 along the width direction X of the first electrode.

[0090] like Figures 4-6 As shown, in another embodiment, along the width direction X of the first electrode, one end of the first current collector 2112 is flush with one end of the first active material layer 2111 to form the first end face 2113 of the first body 211, and the other end of the first current collector 2112 is flush with the other end of the first active material layer 2111 to form the second end face 2114 of the first body 211. The first tab 212 is connected to one end of the first current collector 2112 located at the first end face 2113.

[0091] It should be noted that, in embodiments where the electrode assembly 20 has a stacked structure, the width direction X, length direction Y, and thickness direction Z of the first electrode can be perpendicular to each other. In embodiments where the electrode assembly 20 has a wound structure, the width direction X of the first electrode is parallel to the extension direction of the winding axis of the electrode assembly 20, and the length direction Y of the first electrode corresponds to the winding direction K of the electrode assembly 20.

[0092] In an embodiment where the first electrode 21 is a negative electrode, the first active material layer 2111 is a negative active material layer, and the first current collector 2112 is a negative current collector. The first current collector 2112 and the first active material layer 2111 together form the first body 211 of the first electrode 21. Along the length direction Y of the first electrode, the two opposite end faces of the first active material layer 2111 are flush with the two opposite end faces of the first current collector 2112, thereby forming two opposite third end faces 2115 at both ends along the length direction Y of the first electrode. Along the width direction X of the first electrode, one end of the first current collector 2112 is flush with one end of the first active material layer 2111 to form the first end face 2113 of the first body 211, and the other end of the first current collector 2112 is flush with the other end of the first active material layer 2111 to form the second end face 2114 of the first body 211. The first tab 212 is connected to the end of the first current collector 2112 located at the first end face 2113.

[0093] In some embodiments, the first electrode tab 212 may be a split electrode tab that protrudes from the first end face 2113 and whose dimension in the length direction Y of the first electrode is smaller than the dimension of the first current collector 2112, such as... Figure 3 , Figure 4 As shown. In other embodiments, the first tab 212 may also be a full tab that protrudes from the first end face 2113 and has a dimension in the length direction Y of the first electrode equal to the dimension of the first current collector 2112, such as... Figure 5 , Figure 6 As shown.

[0094] like Figure 5 , Figure 6 As shown, in some embodiments, at least one of the two third end faces 2115 is connected to the second end face 2114 via a chamfered surface 2116.

[0095] Among them, such as Figure 5 As shown, it is possible to connect only one third end face 2115 through a chamfered face 2116, which helps to reduce capacity loss and increase energy density.

[0096] like Figure 6As shown, each third end face 2115 and the second end face 2114 can also be connected by a chamfered surface 2116. Each third end face 2115 and the second end face 2114 are connected by the chamfered surface 2116. The sharpness of the corners between the second end face 2114 and each third end face 2115 is small, which reduces the risk of the sharp corners between the second end face 2114 and the third end face 2115 piercing the isolation membrane 23. This reduces the risk of short circuit failure of the cell 100 during the drop mechanical test due to the sharp corners between the second end face 2114 and the third end face 2115 piercing the isolation membrane 23, thereby improving the safety of the cell 100 drop mechanical test and increasing the pass rate of the cell 100 drop test. Each third end face 2115 is connected to the second end face 2114 through a chamfered surface 2116, which can reduce the risk of short circuit of the battery cell 100 caused by the sharp corner between the second end face 2114 and the third end face 2115 piercing the isolation membrane 23 when the battery cell 100 is in a drop condition, thereby improving the safety performance of the battery cell 100.

[0097] At least one of the two third end faces 2115 is connected to the second end face 2114 via a chamfered surface 2116. This reduces the sharpness of the corners between the second end face 2114 and the third end face 2115, lowering the risk of the corners piercing the separator 23. This reduces the risk of short-circuit failure of the cell 100 during drop testing due to the corners piercing the separator 23, thus improving the safety and pass rate of the cell 100 in drop testing. Furthermore, the connection of at least one of the two third end faces 2115 to the second end face 2114 via a chamfered surface 2116 further reduces the risk of short circuit in the cell 100 due to the corners piercing the separator 23 during drop testing, improving the safety performance of the cell 100.

[0098] like Figure 2 As shown, in an embodiment where the electrode assembly 20 has a wound structure, the first electrode 21 is a positive electrode. Along the winding direction K of the electrode assembly 20, one of the two third end faces 2115 is the winding end 2115' of the first electrode 21, and the other of the two third end faces 2115 is the winding start end 2115' of the first electrode 21. The winding end 2115' is connected to the second end face 2114 through a chamfered surface 2116.

[0099] The first electrode 21 is the positive electrode. The winding end 2115' of the positive electrode is connected to the second end face 2114 through a chamfered surface 2116. This reduces the sharpness of the corner between the second end face 2114 and the third end face 2115, thereby lowering the risk of the sharp corner between the second end face 2114 and the third end face 2115 piercing the separator 23 and causing a short circuit in the cell 100 after the electrode assembly 20 expands to contact the outer casing 10. This improves the safety performance of the cell 100. The connection between the winding end 2115' of the positive electrode and the second end face 2114 through the chamfered surface 2116 also reduces the risk of the cell 100 short-circuiting during drop testing due to the sharp corner between the second end face 2114 and the third end face 2115 piercing the separator 23. This improves the safety of the cell 100 during drop testing and increases the pass rate of the drop test. The positive electrode sheet is connected to the second end face 2114 by a chamfered surface 2116. This can reduce the risk of short circuit in the cell 100 caused by the sharp corner between the second end face 2114 and the third end face 2115 piercing the separator 23 when the cell 100 is in a drop condition, thus improving the safety performance of the cell 100.

[0100] In the embodiment where each third end face 2115 is connected to the second end face 2114 via a chamfered surface 2116, that is, the starting end 2115” and the ending end 2115’ of the positive electrode sheet are respectively connected to the second end face 2114 via a chamfered surface 2116.

[0101] like Figure 5 , Figure 7 As shown, in some embodiments, the chamfered surface 2116 includes at least one bevel 21161. The chamfered surface 2116 including at least one bevel 21161 not only helps to reduce the sharpness between the second end face 2114 and the third end face 2115, but also makes the forming of the chamfered surface 2116 easier, facilitating the manufacturing and forming of the battery cell 100.

[0102] If the chamfered surface 2116 includes at least one bevel 21161, then the first electrode 21 will undergo at least one chamfering process. Each bevel 21161 is arranged at an obtuse angle to the second end face 2114, and each bevel 21161 is arranged at an obtuse angle to the third end face 2115.

[0103] like Figure 5 As shown, the chamfered surface 2116 may include a bevel 21161. For example... Figure 6As shown, the chamfered surface 2116 may also include multiple bevels 21161. In an embodiment where the chamfered surface 2116 includes multiple bevels 21161, the multiple bevels 21161 are arranged sequentially from the second end face 2114 to the third end face 2115. Adjacent bevels 21161 are arranged at an obtuse angle. The chamfered surface 2116 includes multiple bevels 21161, that is, multiple chamfering processes are performed between the second end face 2114 and the third end face 2115, further reducing the sharpness of the corner between the second end face 2114 and the third end face 2115, further reducing the risk of the corner piercing the separator 23 and causing a short circuit, thereby further improving the safety performance of the battery cell 100 in the drop mechanical test, increasing the pass rate of the battery cell 100 in the drop test, and improving the safety performance of the battery cell 100 under drop conditions.

[0104] For example, in some embodiments, the number of bevels 21161 is less than or equal to 3. That is, the number of bevels 21161 can be one, two, or three. Having less than or equal to 3 bevels alleviates the problem of interference during the winding tool's operation caused by too many bevel cuts in the manufacturing process, which could lead to a failure to guarantee cutting accuracy. Figure 7 The diagram shows the case where there are two inclined planes 21161.

[0105] like Figure 7 As shown, in some embodiments, the angle between the inclined surface 21161 and the second end face 2114 is greater than or equal to 151° and less than or equal to 178°.

[0106] In other words, the supplementary angle between the inclined plane 21161 and the second end face 2114 is greater than or equal to 2° and less than or equal to 29°.

[0107] like Figure 7 As shown, the angles between the two inclined planes 21161 and the second end face 2114 are T1 and T2, respectively. Then, 151°≤T1≤178° and 151°≤T2≤178°.

[0108] For example, the angle between the inclined surface 21161 and the second end face 2114 can be 151°, 155°, 158°, 160°, 163°, 165°, 168°, 170°, 173°, 175°, 178°, etc.

[0109] The angle between the inclined surface 21161 and the second end face 2114 is greater than or equal to 151°, which reduces the sharpness of the included angle between the inclined surface 21161 and the second end face 2114. This reduces the risk of short-circuit failure of the battery cell 100 during drop mechanical testing due to the included angle between the second end face 2114 and the third end face 2115 puncturing the separator 23, thereby improving the safety of the battery cell 100 in drop mechanical testing, increasing the pass rate of the drop test, and improving the safety performance of the battery cell 100. The angle between the inclined surface 21161 and the second end face 2114 is less than or equal to 178°, which reduces the processing difficulty and improves the manufacturability of the battery cell 100.

[0110] Furthermore, the angle between the inclined plane 21161 and the second end face 2114 is greater than or equal to 160° and less than or equal to 170°.

[0111] like Figure 7 As shown, the angles between the two inclined planes 21161 and the second end face 2114 are T1 and T2, respectively. Then, 160°≤T1≤170° and 160°≤T2≤170°.

[0112] For example, the angle between the inclined plane 21161 and the second end face 2114 can be 160°, 161°, 162°, 163°, 164°, 166°, 167°, 168°, 169°, 170°, etc.

[0113] The angle between the inclined surface 21161 and the second end face 2114 is greater than or equal to 160°, making the sharpness of the included angle between the inclined surface 21161 and the second end face 2114 less. This further reduces the risk of short-circuit failure of the battery cell 100 during drop mechanical testing due to the included angle between the second end face 2114 and the third end face 2115 puncturing the separator 23, thereby improving the safety of the battery cell 100 in drop mechanical testing, increasing the pass rate of the battery cell 100 in drop testing, and improving the safety performance of the battery cell 100. The angle between the inclined surface 21161 and the second end face 2114 is less than or equal to 170°, further reducing the processing difficulty and improving the manufacturability of the battery cell 100.

[0114] In some embodiments, the chamfered surface 2116 includes a plurality of inclined surfaces 21161, with two adjacent inclined surfaces 21161 being set at an obtuse angle; the ratio of the supplementary angle between the angle of the one of the two adjacent inclined surfaces 21161 closest to the third end face 2115 and the second end face 2114 to the supplementary angle between the one of the two adjacent inclined surfaces 21161 closest to the second end face 2114 and the second end face 2114 is greater than or equal to 1.05 and less than or equal to 1.5.

[0115] like Figure 7 As shown, the supplementary angles of the angles between two adjacent inclined planes 21161 and the second end face 2114 are T and T, respectively.11 T 21 T 11 T is the supplementary angle between the angle of the one closer to the third end face 2115 to the second end face 2114 of two adjacent inclined planes 21161. 21 The angle between the one of two adjacent inclined planes 21161 closest to the second end face 2114 and the second end face 2114 is the supplementary angle, 1.05≤T 11 / T 21 ≤1.5.

[0116] The ratio of the supplementary angle between the one closer to the third end face 2115 and the second end face 2114 of two adjacent inclined planes 21161 to the supplementary angle between the one closer to the second end face 2114 and the second end face 2114 of two adjacent inclined planes 21161 can be 1.05, 1.1, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc.

[0117] The ratio of the supplementary angle between the angle of the one closer to the third end face 2115 and the second end face 2114 of the two adjacent inclined planes 21161 to the supplementary angle between the angle of the one closer to the second end face 2114 and the second end face 2114 of the two adjacent inclined planes 21161 is greater than or equal to 1.05. This reduces the processing difficulty of the cutter, facilitates variable cutting, thereby reducing the processing difficulty of the first electrode 21 and improving the manufacturability of the battery cell 100. The ratio of the supplementary angle between the one of the two adjacent inclined planes 21161 closest to the third end face 2115 and the second end face 2114 to the supplementary angle between the one of the two adjacent inclined planes 21161 closest to the second end face 2114 and the second end face 2114 is less than or equal to 1.5. This reduces the sharpness of the angle between the inclined plane 21161 and the second end face 2114, lowers the risk of short circuit failure caused by the angle between the inclined plane 21161 and the second end face 2114 piercing the separator 23, improves the safety of the battery cell 100 drop mechanical test and increases the pass rate of the battery cell 100 drop test. It can also reduce the risk of short circuit of the battery cell 100 caused by the sharp corner between the inclined plane 21161 and the second end face 2114 piercing the separator 23 when the battery cell 100 is in drop condition, thus improving the safety performance of the battery cell 100.

[0118] Furthermore, the ratio of the supplementary angle between the angle of the one closer to the third end face 2115 and the second end face 2114 of the two adjacent inclined planes 21161 to the supplementary angle between the angle of the one closer to the second end face 2114 and the second end face 2114 of the two adjacent inclined planes 21161 is greater than or equal to 1.1 and less than or equal to 1.3.

[0119] like Figure 7 As shown, 1.1≤T 11 / T 21 ≤1.3.

[0120] The ratio of the supplementary angle between the one closer to the third end face 2115 and the second end face 2114 of two adjacent inclined planes 21161 to the supplementary angle between the one closer to the second end face 2114 and the second end face 2114 of two adjacent inclined planes 21161 can be 1.1, 1.13, 1.17, 1.18, 1.21, 1.22, 1.23, 1.27, 1.28, 1.3, etc.

[0121] The ratio of the supplementary angle between the one of the two adjacent inclined planes 21161 closest to the third end face 2115 and the second end face 2114 to the supplementary angle between the one of the two adjacent inclined planes 21161 closest to the second end face 2114 and the second end face 2114 is greater than or equal to 1.1, which further reduces the processing difficulty of the cutter, facilitates variable cutting, and thus further reduces the processing difficulty of the first electrode 21 and further improves the manufacturability of the battery cell 100. The ratio of the supplementary angle between the one of the two adjacent inclined planes 21161 closest to the third end face 2115 and the second end face 2114 to the supplementary angle between the one of the two adjacent inclined planes 21161 closest to the second end face 2114 and the second end face 2114 is less than or equal to 1.3. This further reduces the sharpness of the angle between the inclined plane 21161 and the second end face 2114, further reduces the risk of short circuit failure caused by the angle between the inclined plane 21161 and the second end face 2114 piercing the isolation membrane 23, further improves the safety of the battery cell 100 drop mechanical test and increases the pass rate of the battery cell 100 drop test. It can also reduce the risk of short circuit of the battery cell 100 caused by the sharp corner between the inclined plane 21161 and the second end face 2114 piercing the isolation membrane 23 when the battery cell 100 is in drop condition, thus improving the safety performance of the battery cell 100.

[0122] In embodiments where the chamfered surface 2116 includes a bevel 21161, such as Figure 7 As shown, the bevel 21161 can be directly connected to the second end face 2114, and the bevel 21161 can be directly connected to the third end face 2115, making the process of the chamfered surface 2116 simpler.

[0123] In an embodiment where the chamfered surface 2116 includes a bevel 21161, the bevel 21161 can be indirectly connected to the second end surface 2114, and the bevel 21161 can be indirectly connected to the third end surface 2115. For example... Figure 8 As shown, the chamfered surface 2116 includes an inclined surface 21161, a first rounded surface 21162, and a second rounded surface 21163. The inclined surface 21161 is connected to the second end surface 2114 through the first rounded surface 21162, and the inclined surface 21161 is connected to the third end surface 2115 through the second rounded surface 21163.

[0124] The inclined surface 21161 and the second end face 2114 are indirectly connected by the first rounded corner surface 21162, thus creating a smooth transition between the inclined surface 21161 and the second end face 2114. The inclined surface 21161 and the third end face 2115 are indirectly connected by the second rounded corner surface 21163, thus creating a smooth transition between the inclined surface 21161 and the third end face 2115.

[0125] The inclined surface 21161 is connected to the second end face 2114 through the first rounded corner surface 21162, and the inclined surface 21161 is connected to the third end face 2115 through the second rounded corner surface 21163. This avoids the formation of sharp corners between the inclined surface 21161 and the second end face 2114, and between the inclined surface 21161 and the third end face 2115, thereby reducing the risk of sharp corners piercing the separator 23. This also reduces the risk of short circuit in the battery cell 100 caused by the sharp corners between the second end face 2114 and the third end face 2115 piercing the separator 23, improving the safety performance of the battery cell 100 in drop mechanical testing, increasing the pass rate of the drop test, and enhancing the safety performance of the battery cell 100 under drop conditions.

[0126] In an embodiment where the chamfered surface 2116 includes multiple bevels 21161, one of the multiple bevels 21161 can be directly connected to the second end face 2114, another of the multiple bevels 21161 can be directly connected to the third end face 2115, and two adjacent bevels 21161 can also be directly connected, making the process of the chamfered surface 2116 simpler.

[0127] In embodiments where the chamfered surface 2116 includes multiple bevels 21161, one of the multiple bevels 21161 may be indirectly connected to the second end face 2114, and one of the multiple bevels 21161 may be indirectly connected to the third end face 2115. For example... Figure 9 As shown, the chamfered surface 2116 also includes a first rounded surface 21162 and a second rounded surface 21163. One inclined surface 21161 is connected to the second end surface 2114 through the first rounded surface 21162, and the other inclined surface 21161 is connected to the third end surface 2115 through the second rounded surface 21163.

[0128] One inclined surface 21161 is indirectly connected to the second end face 2114 through a first rounded corner surface 21162, thus the inclined surface 21161 and the second end face 2114 have a smooth transition. Another inclined surface 21161 is indirectly connected to the third end face 2115 through a second rounded corner surface 21163, thus the inclined surface 21161 and the third end face 2115 have a smooth transition.

[0129] One inclined surface 21161 is connected to the second end face 2114 through the first rounded corner surface 21162, and the other inclined surface 21161 is connected to the third end face 2115 through the second rounded corner surface 21163. This avoids the formation of sharp corners between the inclined surface 21161 and the second end face 2114, and between the inclined surface 21161 and the third end face 2115, thereby reducing the risk of sharp corners piercing the separator 23. This also reduces the risk of short circuit in the battery cell 100 caused by the sharp corners between the second end face 2114 and the third end face 2115 piercing the separator 23, improving the safety performance of the battery cell 100 in drop mechanical testing, increasing the pass rate of the drop test, and enhancing the safety performance of the battery cell 100 under drop conditions.

[0130] Please continue to refer to Figure 9 In an embodiment where the chamfered surface 2116 includes multiple bevels 21161, the chamfered surface 2116 also includes a third rounded corner surface 211164, and two adjacent bevels 21161 are connected by the third rounded corner surface 211164.

[0131] Two adjacent inclined planes 21161 are indirectly connected by a third rounded corner surface 211164, so the two adjacent inclined planes 21161 have a smooth transition.

[0132] The two adjacent inclined surfaces 21161 are connected by a third rounded corner surface 211164 to avoid the formation of sharp corners between the two adjacent inclined surfaces 21161. This reduces the risk of short circuit in the battery cell 100 caused by the sharp corner between the second end surface 2114 and the third end surface 2115 piercing the separator 23, thereby improving the safety performance of the battery cell 100 in the drop mechanical test, increasing the pass rate of the drop test, and improving the safety performance of the battery cell 100 when it is in a drop condition.

[0133] The radii of the first rounded surface 21162, the second rounded surface 21163, and the third rounded surface 211164 can be the same or different.

[0134] like Figure 8 , Figure 9 As shown, in some embodiments, the radius of the first rounded corner 21162 is R1, the radius of the third rounded corner 211164 is R3, and 0.6≤R3 / R1≤1.5.

[0135] For example, R3 / R1 can be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 / 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc.

[0136] By limiting the ratio of the radius of the third rounded corner surface 211164 to the radius of the first rounded corner surface 21162 to 0.6≤R3 / R1≤1.5, the difference between the radius of the third rounded corner surface 211164 and the radius of the first rounded corner surface 21162 can be controlled within a reasonable range. This ensures that the difference between the radius of the third rounded corner surface 211164 and the radius of the first rounded corner surface 21162 is not too large or too small, reducing the risk of tearing due to uneven stress on the first electrode 21 during the charging and discharging process of the battery cell 100 caused by the difference between the radius of the first rounded corner surface 211162 and the radius of the third rounded corner surface 211164 being too large or too small, thereby improving the safety performance of the battery cell 100.

[0137] Please continue to refer to Figure 8 , Figure 9 In some embodiments, the radius of the second rounded corner 21163 is R2, and the radius of the third rounded corner 211164 is R3, where 0.6 ≤ R3 / R2 ≤ 1.5.

[0138] For example, R3 / R2 can be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 / 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc.

[0139] By limiting the ratio of the radius of the third rounded corner surface 211164 to the radius of the second rounded corner surface 21163 to 0.6≤R3 / R2≤1.5, the difference between the radius of the third rounded corner surface 211164 and the radius of the second rounded corner surface 21163 can be controlled within a reasonable range. This ensures that the difference between the radius of the third rounded corner surface 211164 and the radius of the second rounded corner surface 21163 is not too large or too small, reducing the risk of tearing due to uneven stress on the first electrode 21 during the charging and discharging process of the battery cell 100 caused by the difference between the radius of the second rounded corner surface 21163 and the radius of the third rounded corner surface 211164 being too large or too small, thereby improving the safety performance of the battery cell 100.

[0140] Specifically, the radius of the first rounded corner surface 21162 is R1, where 0.2mm ≤ R1 ≤ 3mm. R1 ≥ 0.2mm helps reduce the processing difficulty of the first rounded corner surface 21162, improving the manufacturability and practicality of the battery cell 100. R1 ≤ 3mm reduces the energy density loss caused by processing the first rounded corner surface 21162.

[0141] For example, R1 can be 0.2mm, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 1.9mm, 2mm, 2.2mm, 2.5mm, 2.7mm, 2.9mm, 3mm, etc.

[0142] In some embodiments, the radius of the second rounded corner surface 21163 is R2, where 0.2mm ≤ R2 ≤ 3mm. R2 ≥ 0.2mm helps reduce the processing difficulty of the second rounded corner surface 21163, improving the manufacturability and practicality of the battery cell 100. R2 ≤ 3mm reduces the energy density loss caused by processing the second rounded corner surface 21163.

[0143] For example, R2 can be 0.2mm, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 1.9mm, 2mm, 2.2mm, 2.5mm, 2.7mm, 2.9mm, 3mm, etc.

[0144] In some embodiments, the radius of the third rounded corner surface 211164 is R3, where 0.2mm ≤ R3 ≤ 3mm. R3 ≥ 0.2mm helps reduce the processing difficulty of the third rounded corner surface 211164, improving the manufacturability and practicality of the battery cell 100. R3 ≤ 3mm reduces the energy density loss caused by processing the third rounded corner surface 211164.

[0145] For example, R3 can be 0.2mm, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 1.9mm, 2mm, 2.2mm, 2.5mm, 2.7mm, 2.9mm, 3mm, etc.

[0146] like Figures 7-9 As shown, in some embodiments, the chamfered surface 2116 intersects the third end surface 2115 at a first position Q1. Along the width direction X of the first electrode, the distance between the first position Q1 and the second end surface 2114 is L1, where 1mm≤L1≤5mm.

[0147] In an embodiment where the chamfered surface 2116 includes at least one inclined surface 21161, if the inclined surface 21161 is directly connected to the third end surface 2115, then the first position Q1 is the position where the inclined surface 21161 intersects with the third end surface 2115.

[0148] In the embodiment where the inclined surface 21161 and the third end face 2115 are connected by the second rounded corner surface 21163, the first position Q1 can be the position where the second rounded corner surface 21163 and the third end face 2115 are tangent.

[0149] For example, L1 can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, etc.

[0150] 1mm≤L1 reduces the risk of debris generated during chamfering being easily caught in the cell 100 and reduces the difficulty of chamfering. L1≤5mm reduces the capacity loss caused by processing the chamfered surface 2116, thereby reducing energy density loss and ensuring product competitiveness.

[0151] Furthermore, 2mm≤L1≤3.5mm.

[0152] For example, L1 can be 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, etc.

[0153] L1≥2mm further reduces the risk of debris generated during chamfering being easily entangled into the cell 100 and further reduces the difficulty of chamfering. L1≤3.5mm further reduces the capacity loss generated by processing the chamfered surface 2116, thereby further reducing energy density loss and ensuring product competitiveness.

[0154] In some embodiments, the chamfered surface 2116 intersects the third end surface 2115 at a first position Q1. Along the width direction X of the first electrode, the distance between the first position Q1 and the second end surface 2114 is L1, and the size of the first active material layer 2111 is L, where 0.01≤L1 / L≤0.2.

[0155] For example, L1 / L can be 0.01, 0.03, 0.05, 0.07, 0.09, 0.1, 0.13, 0.15, 0.17, 0.19, 0.2, etc.

[0156] When L1 / L ≥ 0.01, it reduces the difficulty of multi-segment cutting and processing when the chamfered surface 2116 is multi-segmented, thus reducing the loss of 100% yield of the battery cell. When L1 / L ≤ 0.2, it reduces the energy density loss when processing the chamfered surface 2116, ensuring the product's high competitiveness.

[0157] Furthermore, 0.03 ≤ L1 / L ≤ 0.1.

[0158] For example, L1 / L can be 0.03, 0.35, 0.04, 0.45, 0.05, 0.55, 0.06, 0.65, 0.7, 0.75, 0.08, 0.85, 0.09, 0.95, 0.1, etc.

[0159] With L1 / L ≥ 0.03, when the chamfered surface 2116 is multi-segmented, the difficulty of multi-segment cutting can be further reduced, thereby reducing the 100% yield loss of the battery cell. With L1 / L ≤ 0.1, the energy density loss during the processing of the chamfered surface 2116 is further reduced, ensuring higher product competitiveness.

[0160] like Figure 10 , Figure 11 As shown, in an embodiment where the first tab 212 has a split structure, one of the two third end faces 2115 and the first end face 2113 can be connected by a chamfered surface 2116. This reduces the sharpness of the corner between the first end face 2113 and the third end face 2115, thereby reducing the risk of the corner between the first end face 2113 and the third end face 2115 piercing the separator 23. This reduces the risk of short circuit failure of the cell 100 during drop mechanical testing due to the corner between the first end face 2113 and the third end face 2115 piercing the separator 23, improving the safety of the cell 100 drop mechanical testing and increasing the pass rate of the cell 100 drop test. At least one of the two third end faces 2115 is connected to the first end face 2113 through a chamfered surface 2116, which can reduce the risk of short circuit of the battery cell 100 caused by the sharp corner between the first end face 2113 and the third end face 2115 piercing the isolation membrane 23 when the battery cell 100 is in a drop condition, thereby improving the safety performance of the battery cell 100.

[0161] In an embodiment where the first current collector 2112 includes a first region 21121 coated with a first active material layer 2111 and a second region 21122 uncoated with an active material layer, the chamfered surface 2116 connecting the first end face 2113 and the third end face 2115 can be entirely located in the second region 21122, or the chamfered surface 2116 connecting the first end face 2113 and the third end face 2115 can be partially located in the second region 21122 and the other part located in the first region 21121. Figure 9 The diagram shows a case where the chamfered surface 2116 connecting the first end face 2113 and the third end face 2115 is partially located in the second region 21122 and partially located in the first region 21121.

[0162] like Figure 12 , Figure 13 As shown, in an embodiment where the first electrode tab 212 is a full electrode tab, along the width direction X of the first electrode sheet, the first electrode tab 212 has a fourth end face 2121 facing away from the first end face 2113, and along the length direction Y of the first electrode sheet, the first electrode tab 212 has two opposing fifth end faces 2122, which are flush with the two third end faces 2115 respectively. Wherein, as... Figure 12As shown, at least one of the two fifth end faces 2122 is connected to the fourth end face 2121 via a chamfered surface 2116. This reduces the sharpness of the corners between the fourth end face 2121 and the fifth end face 2122, lowering the risk of the corners piercing the separator 23. This reduces the risk of short-circuit failure of the cell 100 during drop testing due to the corners piercing the separator 23, thus improving the safety and pass rate of the cell 100 in drop testing. Furthermore, the connection of at least one of the two fifth end faces 2122 to the fourth end face 2121 via the chamfered surface 2116 further reduces the risk of short circuit in the cell 100 due to the corners piercing the separator 23 during drop testing, improving the safety performance of the cell 100.

[0163] like Figure 13 As shown, at least one of the two third end faces 2115 is connected to the fourth end face 2121 via a chamfered surface 2116. This reduces the sharpness of the corners between the fourth end face 2121 and the third end face 2115, lowering the risk of the corners piercing the separator 23. This reduces the risk of short-circuit failure of the cell 100 during drop testing due to the corners piercing the separator 23, thus improving the safety and pass rate of the cell 100 in drop testing. Furthermore, the connection of at least one of the two third end faces 2115 to the fourth end face 2121 via the chamfered surface 2116 further reduces the risk of short circuit in the cell 100 due to the corners piercing the separator 23 during drop testing, improving the safety performance of the cell 100.

[0164] This application also provides an electrical device, which includes the battery cell 100 provided in any of the above embodiments.

[0165] The battery cell 100 provided in any of the above embodiments has good safety, which is beneficial to improving the electrical safety of electrical equipment powered by the battery cell 100.

[0166] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art.

Claims

1. An electric cell, characterized by, The electrode assembly comprises a first tab, the first tab comprising a first body and a first tab lug, the first body comprising a first active material layer, the first body having opposite first and second end faces along a width direction of the first tab, the first tab lug being connected to the first end face, one end of the first active material layer extending to the second end face, the first body having two opposite third end faces along a length direction of the first tab, two ends of the first active material layer extending to the two third end faces respectively. At least one of the two third end faces is connected to the second end face by a chamfered face. The chamfered face comprises at least one bevel.

2. The electric cell of claim 1, wherein, The chamfered face comprises one bevel, a first rounded face and a second rounded face, the bevel being connected to the second end face by the first rounded face, the bevel being connected to the third end face by the second rounded face.

3. The electric cell of claim 2, wherein, The chamfered face comprises a plurality of bevels, two adjacent bevels being arranged at an obtuse angle.

4. The cell of claim 2, wherein, The chamfered face further comprises a first rounded face and a second rounded face, one bevel being connected to the second end face by the first rounded face, another bevel being connected to the third end face by the second rounded face.

5. The electric cell of claim 4, wherein, The chamfered face further comprises a third rounded face, two adjacent bevels being connected by the third rounded face.

6. The electric cell of claim 5, wherein, The first rounded face has a radius R1, the second rounded face has a radius R2, and the third rounded face has a radius R3, 0.6≤R3 / R1≤1.5, and 0.6≤R3 / R2≤1.

5.

7. The electric cell of claim 6, wherein, The first rounded face has a radius R1, the second rounded face has a radius R2, and the third rounded face has a radius R3, 0.2mm≤R1≤3mm, 0.2mm≤R2≤3mm, and 0.2mm≤R3≤3mm.

8. The electric cell of claim 6, wherein, The angle between the bevel and the second end face is greater than or equal to 151° and less than or equal to 178°.

9. The electric cell of claim 2, wherein, The angle between the bevel and the second end face is greater than or equal to 160° and less than or equal to 170°.

10. The electric cell of claim 9, wherein, The chamfered face comprises a plurality of bevels, two adjacent bevels being arranged at an obtuse angle.

11. The electric cell of claim 2, wherein, The ratio of the supplementary angle of one of the two adjacent bevels close to the third end face to the second end face to the supplementary angle of the other of the two adjacent bevels close to the second end face to the second end face is greater than or equal to 1.05 and less than or equal to 1.

5. The ratio of the supplementary angle of one of the two adjacent bevels close to the third end face to the second end face to the supplementary angle of the other of the two adjacent bevels close to the second end face to the second end face is greater than or equal to 1.1 and less than or equal to 1.

3.

12. The electric cell of claim 11, wherein, The number of bevels is less than or equal to 3.

13. The electric cell of claim 2, wherein, The chamfered face intersects the third end face at a first position, the distance between the first position and the second end face along the width direction of the first tab is L1, 1mm≤L1≤5mm.

14. The electrically charged cell of claim 1, wherein, 2mm≤L1≤3.5mm.

15. The electric cell of claim 14, wherein, ​ 16. The electrically charged cell of claim 1, wherein, The chamfer surface intersects the third end surface at a first position, and the distance between the first position and the second end surface along the width direction of the first tab is L1, and the size of the first active material layer is L, and 0.01≤L1 / L≤0.

2.

17. The electric cell of claim 16, wherein, 0.03≤L1 / L≤0.

1.

18. The electrically core of claim 1, wherein, Each of the third end surfaces is connected to the second end surface through one of the chamfer surfaces.

19. The electrically charged cell of claim 1, wherein, The electrode assembly is in a wound structure, the first tab is a positive electrode tab, and along the winding direction of the electrode assembly, one of the two third end surfaces is a winding end tab of the first tab, and the other of the two third end surfaces is a winding start tab of the first tab, and the winding end tab is connected to the second end surface through one of the chamfer surfaces.

20. The electrically core of claim 1, wherein, The battery cell is a cylindrical battery cell.

21. An electrical device, comprising: A battery cell according to any one of claims 1-20.

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