Battery cell and electric device

Abstract

The present application provides a battery cell and an electric device. The battery cell comprises an electrode assembly. The electrode assembly has a laminated structure. The electrode assembly comprises multiple first electrode sheets, multiple second electrode sheets, and multiple separators. Each first electrode sheet comprises a first uncoated region, each second electrode sheet comprises a first notch, and in a first direction, at least a portion of the first uncoated region is exposed to the first notch; the first notch comprises a first edge and a second edge connected to each other, and in a second direction, the first uncoated region extends beyond the first edge; and each separator comprises a first protruding portion extending beyond a corresponding second edge in a third direction, first protruding portions of the multiple separators are connected to each other, and when viewed in the first direction, the first protruding portions are located in the first notches. The insulation between the first uncoated regions and the second electrode sheets can be achieved, and when the battery cell is subjected to external force or falls, the possibility of a short circuit resulting from contact between the first uncoated regions and the second electrode sheets is relatively low, thereby making the battery cell safer, and generating less impact on the energy density of the battery cell.

Description

Battery cells and electrical equipment Cross-references to related applications

[0001] This application claims priority to Chinese patent application CN202410840359.3, entitled "Battery Cell and Electrical Equipment", filed on June 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery cell and an electrical device. Background Technology

[0003] With the rapid development of electronic information technology, various electronic devices are also developing towards intelligence and multi-functionality, and the requirements for battery safety are becoming increasingly stringent.

[0004] Currently, battery cells typically use adhesive tape to insulate the electrodes from opposite polarities. However, the overlap of the adhesive tape with the active material layer of the battery cell increases the cell's thickness and affects its energy density. Summary of the Invention

[0005] This application provides a battery cell and an electrical device that can improve the energy density of the battery cell.

[0006] In a first aspect, this application provides a battery cell, which includes an electrode assembly. The electrode assembly has a stacked structure and includes a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators. The first electrodes and second electrodes have opposite polarities. The plurality of first electrodes and second electrodes are stacked along a first direction, and the plurality of separators are respectively disposed between the first electrodes and the second electrodes. Each first electrode has a first empty foil area, and each second electrode has a first notch. Along the first direction, at least a portion of the first empty foil area is exposed to the first notch. The first notch has a first edge and a second edge, and the first edge is connected to the second edge. Along the second direction, the first empty foil area extends beyond the first edge. The separators have a first extended portion that extends beyond the second edge along a third direction, and the first extended portions of the plurality of separators are connected. When viewed along the first direction, the first extended portion is located within the first notch. The first direction is the thickness direction of the electrode assembly, and the first direction, the second direction, and the third direction are perpendicular to each other.

[0007] In the above technical solution, each first electrode has a first empty foil area, and each second electrode has a first notch. Along the first direction, at least a portion of the first empty foil area is exposed to the first notch, which can reduce the volume of the first empty foil area protruding from the electrode assembly. This results in a smaller gap space reserved between the electrode assembly and the shell for accommodating the first empty foil area, which is beneficial to improving the energy density of the battery cell. Furthermore, when the battery cell is subjected to external force, the possibility of the electrode assembly shaking relative to the shell is small, and the possibility of the first empty foil area short-circuiting with the second electrode is also small, which can reduce the risk of thermal runaway of the battery cell. The separator has a first protruding portion extending beyond the second edge along the third direction. The first protruding portions of multiple separators are connected, so that the first protruding portions of multiple separators can achieve insulation between the first empty foil area and the second electrode. This can reduce the possibility of the first empty foil area short-circuiting with the second electrode when the battery cell is subjected to external force or dropped, resulting in higher safety of the battery cell. Moreover, the first protruding portion does not increase the thickness of the electrode assembly, and the first protruding portion is located within the first notch and does not extend beyond the edge of the electrode assembly in the length or width direction, thus having a small impact on the energy density of the battery cell.

[0008] In some embodiments of this application, the electrode assembly has a first side and a second side opposite to each other along a first direction; along the first direction, first protrusions of a plurality of diaphragms converge toward the first side and are connected.

[0009] In the above technical solution, by having the first protruding parts of multiple diaphragms converge and connect towards the first side along the first direction, the connection method of the first protruding parts of multiple diaphragms is simple and easy to operate.

[0010] In some embodiments of this application, the plurality of diaphragms includes a first diaphragm located on the second side, the width of the first extended portion of the first diaphragm along the third direction is W1, and the thickness of the electrode assembly is H1, satisfying W1≥H1.

[0011] In the above technical solution, by making the width W1 of the first extended portion of the first separator along the third direction and the thickness H1 of the electrode assembly satisfy W1≥H1, the first extended portion of the first separator can extend to the second side of the electrode assembly, so that the first extended portions of multiple separators can be connected on the first side of the electrode assembly, thereby facilitating the fabrication of the battery cell.

[0012] In some embodiments of this application, the plurality of diaphragms includes a first diaphragm located on the second side, wherein the width of the first extended portion of the first diaphragm along the third direction is W1, satisfying W1≥2mm.

[0013] In the above technical solution, by making the width W1 of the first extended portion of the first diaphragm along the third direction satisfy W1≥2mm, the first extended portion of the first diaphragm can extend to the first side of the electrode assembly, so that the first extended portions of multiple diaphragms can be connected on the first side of the electrode assembly.

[0014] In some embodiments of this application, the plurality of diaphragms includes a second diaphragm located on a first side, wherein the width of the first extended portion of the second diaphragm along a third direction is W2, satisfying W2≥0.2mm.

[0015] In the above technical solution, by ensuring that the width W2 of the first extended portion of the second diaphragm along the third direction satisfies W2≥0.2mm, it is easy for the first extended portion of the second diaphragm to connect with the first extended portions of other diaphragms, resulting in a larger connection area and higher connection reliability.

[0016] In some embodiments of this application, the first extensions of multiple diaphragms are connected to form a connecting portion, and when viewed along a third direction, there is a gap between the connecting portion and the first empty foil area.

[0017] In the above technical solution, by making a gap between the connecting part and the first empty foil area when viewed along a third direction, the possibility of interference between the connecting part and the first empty foil area can be reduced, which facilitates the subsequent processing of the first empty foil area. It can also reduce the possibility of the first excess part of multiple diaphragms separating due to interference between the connecting part and other components, thereby further reducing the possibility of short circuit between the first empty foil area and the second electrode, making the cell safer.

[0018] In some embodiments of this application, the first extended portions of a plurality of diaphragms converge toward the center and connect in a first direction.

[0019] In the above technical solution, by having the first protruding parts of multiple diaphragms converge and connect towards the center in the first direction, the connection method of the first protruding parts of multiple diaphragms is simpler and easier to operate. Furthermore, the widths of the first protruding parts of the first diaphragm located on the second side and the first protruding parts of the second diaphragm located on the first side are both smaller, thereby reducing the possibility of interference between the first protruding parts of multiple diaphragms and the first empty foil area during connection, and further facilitating the connection of the first protruding parts of multiple diaphragms.

[0020] In some embodiments of this application, the first overhangs of multiple diaphragms are thermally bonded.

[0021] In the above technical solution, by thermally bonding the first protruding parts of multiple separators, the possibility of separation of the first protruding parts of multiple separators after being soaked in electrolyte is reduced. This allows the first protruding parts of multiple separators to maintain insulation of the first empty foil area and the second electrode, further reducing the possibility of short circuit between the first empty foil area and the second electrode, thus making the cell safer.

[0022] In some embodiments of this application, the first empty foil area is located at the first corner of the first electrode, and the first notch is located at the second corner of the second electrode.

[0023] In the above technical solution, by placing the first empty foil area at the first corner of the first electrode and the first notch at the second corner of the second electrode, it is convenient to prepare the first notch and the first empty foil area, and it is convenient to draw out the first empty foil area.

[0024] In some embodiments of this application, the second electrode has a second empty foil region located at a third corner, and the first electrode has a second notch located at a fourth corner. Along a first direction, the second empty foil region and the second notch at least partially overlap. The second notch has a third edge and a fourth edge, which are connected. Along a second direction, the second empty foil region extends beyond the third edge. The diaphragm has a second extended portion extending beyond the fourth edge along a third direction, and the second extended portions of multiple diaphragms are connected.

[0025] In the above technical solution, by ensuring that the second empty foil area and the second notch at least partially overlap along the first direction, the volume of the second empty foil area protruding from the electrode assembly can be reduced. This results in a smaller gap space reserved between the electrode assembly and the outer casing for accommodating the second empty foil area, which is beneficial for improving the energy density of the battery cell. Furthermore, when the battery cell is subjected to external force, the possibility of the electrode assembly shaking relative to the outer casing is smaller, and the possibility of the second empty foil area short-circuiting with the first electrode plate is also smaller, which can reduce the risk of thermal runaway of the battery cell. By positioning the second empty foil area at the triangular position of the second electrode plate and the second notch at the fourth corner position of the first electrode plate, the preparation of the second notch and the second empty foil area can be facilitated, as well as the lead-out of the second empty foil area. The separator has a second protruding portion extending beyond the fourth edge along the third direction. The second protruding portions of multiple separators are connected, enabling the second protruding portions of multiple separators to achieve insulation between the second empty foil area and the first electrode plate. This reduces the possibility of the second empty foil area short-circuiting with the first electrode plate when the battery cell is subjected to external force or drops, resulting in higher battery cell safety. Moreover, the second protruding portion does not increase the thickness of the electrode assembly, which is beneficial for improving the energy density of the battery cell.

[0026] In some embodiments of this application, the first notch has a fifth edge, the fifth edge and the second edge are spaced apart along a third direction, and the first edge connects the second edge and the fifth edge; the diaphragm has a third overhang extending beyond the fifth edge along a third direction, and the third overhangs of a plurality of diaphragms are connected.

[0027] In the above technical solution, the diaphragm has a third overhang extending beyond the fifth edge in a third direction. The third overhangs of multiple diaphragms are connected, so that the third overhangs of multiple diaphragms can achieve insulation between the first empty foil area and the second electrode. This makes it less likely that the first empty foil area and the second electrode will short-circuit when the cell is subjected to external force or dropped, thus making the cell safer. In addition, the third overhang does not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the cell.

[0028] Secondly, this application provides an electrical device including a battery cell as described above, the battery cell being used to provide electrical energy. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described 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.

[0030] Figure 1 is a three-dimensional structural diagram of a battery cell provided in some embodiments of this application;

[0031] Figure 2 is a perspective view of a portion of the structure of a battery cell provided in some embodiments of this application;

[0032] Figure 3 is an exploded view of a portion of the battery cell structure provided in some embodiments of this application;

[0033] Figure 4 is a schematic diagram of the structure of the first electrode of the battery cell provided in some embodiments of this application;

[0034] Figure 5 is a schematic diagram of the structure of the second electrode of the battery cell provided in some embodiments of this application;

[0035] Figure 6 is a schematic diagram from one perspective of a portion of the battery cell structure provided in some embodiments of this application before the first extended portion is retracted;

[0036] Figure 7 is a schematic diagram from one perspective of the battery cell structure provided in some embodiments of this application in the state after the first extended part is retracted;

[0037] Figure 8 is a partially enlarged structural diagram of point A in the battery cell in Figure 6;

[0038] Figure 9 is a partially enlarged structural diagram of point B in the battery cell in Figure 2;

[0039] Figure 10 is a partially enlarged structural diagram of point C in the battery cell in Figure 6;

[0040] Figure 11 is a schematic diagram of the structure of the separator of the battery cell provided in some embodiments of this application;

[0041] Figure 12 is a schematic diagram from one perspective of a partial structure of a battery cell provided in some other embodiments of this application;

[0042] Figure 13 is a schematic diagram of the structure of the second electrode of the battery cell provided in some other embodiments of this application.

[0043] Icons: 10-Battery cell; 100-Electrode assembly; 110-First electrode; 111-First empty foil area; 112-Second notch; 1121-Third edge; 1122-Fourth edge; 120-Second electrode; 121-First notch; 1211-First edge; 1212-Second edge; 1213-Fifth edge; 122-Second empty foil area; 130-Separator; 130a-First separator; 130b-Second separator; 131-First protrusion; 132-Second protrusion; 133-Third notch; 134-Fourth notch; 135-Third protrusion; 200-Housing; 310-First electrical connector; 320-Second electrical connector; 330-First seal; 340-Second seal; X-First direction; Y-Second direction; Z-Third direction. Specific embodiments.

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0045] 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 specification 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 specification, claims and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] The terms "first," "second," etc., in the specification, claims, or the accompanying drawings of this application are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0047] 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.

[0048] 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.

[0049] Batteries possess outstanding advantages such as high energy density, low environmental pollution, high power density, long lifespan, wide applicability, and low self-discharge coefficient, making them a crucial component of today's new energy development. With the advancement of the new energy industry, batteries are gradually evolving towards higher energy density and higher power density. However, the limited volume of the battery compartment in electrical equipment restricts the ability to increase energy density simply by increasing cell volume. Therefore, modifying the cell's structure to improve its energy density is a more feasible approach.

[0050] Currently, battery cells typically use adhesive tape to insulate the electrodes from opposite polarities. However, to ensure a more secure adhesion, the tape needs to cover a larger area. Consequently, part of the tape used for tab insulation is attached to the active material layer of the electrode. This means that the tape overlaps with the active material layer of the battery cell in the thickness direction, increasing the cell's thickness and thus affecting its energy density.

[0051] To improve the energy density of a battery cell, this application provides a battery cell including an electrode assembly. The electrode assembly has a stacked structure and includes multiple first electrodes, multiple second electrodes, and multiple separators. The first electrodes and second electrodes have opposite polarities. The multiple first electrodes and multiple second electrodes are stacked along a first direction, and multiple separators are respectively disposed between the first electrodes and the second electrodes. Each first electrode has a first empty foil area, and each second electrode has a first notch. Along the first direction, at least a portion of the first empty foil area is exposed to the first notch. The first notch has a first edge and a second edge, and the first edge is connected to the second edge. Along the second direction, the first empty foil area extends beyond the first edge. The separators have a first extended portion that extends beyond the second edge along a third direction, and the first extended portions of the multiple separators are connected. When viewed along the first direction, the first extended portion is located within the first notch. The first direction is the thickness direction of the electrode assembly, and the first direction, the second direction, and the third direction are perpendicular to each other.

[0052] In this type of battery cell, each first electrode has a first empty foil area, and each second electrode has a first notch. Along a first direction, at least a portion of the first empty foil area is exposed to the first notch, which reduces the volume of the first empty foil area protruding from the electrode assembly. This results in a smaller gap between the electrode assembly and the casing for accommodating the first empty foil area, which is beneficial for improving the energy density of the battery cell. Furthermore, when the battery cell is subjected to external force, the possibility of the electrode assembly shaking relative to the casing is relatively small, and the possibility of a short circuit between the first empty foil area and the second electrode is also relatively small, which reduces the risk of thermal runaway in the battery cell. The separator has a first protruding portion extending beyond the second edge along a third direction. The first protruding portions of multiple separators are connected, so that the first protruding portions of multiple separators can achieve insulation between the first empty foil area and the second electrode. This reduces the possibility of a short circuit between the first empty foil area and the second electrode when the battery cell is subjected to external force or drops, resulting in higher safety of the battery cell. Moreover, the first protruding portion does not increase the thickness of the electrode assembly, and the first protruding portion is located within the first notch and does not extend beyond the edge of the electrode assembly in the length or width direction, thus having a small impact on the energy density of the battery cell.

[0053] The battery cell provided in this application embodiment can be a secondary battery or a primary battery, such as a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., and this application embodiment is not limited in this respect. The battery cell can be cylindrical, flat, cuboid, or other shapes, etc., and this application embodiment is not limited in this respect either.

[0054] This application provides an electrical device that uses battery cells as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc.

[0055] Referring to Figures 1 to 3, Figure 1 is a three-dimensional structural schematic diagram of a battery cell provided in some embodiments of this application; Figure 2 is a three-dimensional schematic diagram of a partial structure of a battery cell provided in some embodiments of this application; and Figure 3 is an exploded schematic diagram of a partial structure of a battery cell provided in some embodiments of this application.

[0056] Some embodiments of this application provide a battery cell 10, which includes an electrode assembly 100. The electrode assembly 100 has a stacked structure and includes a plurality of first electrode plates 110, a plurality of second electrode plates 120, and a plurality of separators 130. The first electrode plates 110 and the second electrode plates 120 have opposite polarities. The plurality of first electrode plates 110 and the plurality of second electrode plates 120 are stacked along a first direction X, and the plurality of separators 130 are respectively disposed between the first electrode plates 110 and the second electrode plates 120.

[0057] Referring to Figures 4 and 5, Figure 4 is a schematic diagram of the structure of the first electrode of the battery cell provided in some embodiments of this application; Figure 5 is a schematic diagram of the structure of the second electrode of the battery cell provided in some embodiments of this application.

[0058] In some embodiments, each first electrode 110 has a first empty foil region 111, and each second electrode 120 has a first notch 121, with at least a portion of the first empty foil region 111 exposed to the first notch 121 along a first direction X.

[0059] By making each first electrode 110 have a first empty foil area 111 and each second electrode 120 have a first notch 121, with at least a portion of the first empty foil area 111 exposed to the first notch 121 along the first direction X, the volume of the first empty foil area 111 protruding from the electrode assembly 100 can be reduced, making the space reserved between the electrode assembly 100 and the housing for accommodating the first empty foil area 111 smaller. This is beneficial to improving the energy density of the battery cell 10, and when the battery cell 10 is subjected to external force, the possibility of the electrode assembly 100 shaking relative to the housing is smaller, and the possibility of the first empty foil area 111 contacting and short-circuiting with the second electrode 120 is also smaller, which can reduce the risk of thermal runaway of the battery cell 10.

[0060] In some embodiments, the battery cell 10 is arranged in a cuboid shape with rounded corners, which can better fit the rounded battery compartment in the electrical device.

[0061] In other embodiments, the apex of the battery cell 10 may also be square.

[0062] Referring also to Figures 6 to 9, Figure 6 is a schematic diagram from one perspective of the partial structure of the battery cell provided in some embodiments of this application before the first extended portion is retracted; Figure 7 is a schematic diagram from one perspective of the partial structure of the battery cell provided in some embodiments of this application after the first extended portion is retracted; Figure 8 is a partial enlarged structural schematic diagram of point A of the battery cell in Figure 6; Figure 9 is a partial enlarged structural schematic diagram of point B of the battery cell in Figure 2.

[0063] In some embodiments, the first notch 121 has a first edge 1211 and a second edge 1212, the first edge 1211 and the second edge 1212 are connected, and the first empty foil region 111 extends beyond the first edge 1211 along the second direction Y. The separator 130 has a first protruding portion 131 extending beyond the second edge 1212 along the third direction Z, and the first protruding portions 131 of a plurality of separators 130 are connected. The first direction X is the thickness direction of the electrode assembly 100, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. Viewed along the first direction X, the first protruding portion 131 is located within the first notch 121, and the first notch 121 refers to the region enclosed by the extension lines of the edges of the cell in the second direction Y and the third direction Z and the first edge 1211 and the second edge 1212. The first protruding portion 131 is located within the first notch 121 and does not extend beyond the edge of the cell in the length or width direction, and does not affect the energy density of the cell.

[0064] By making the diaphragm 130 have a first protruding portion 131 extending beyond the second edge 1212 along the third direction Z, and connecting the first protruding portions 131 of the plurality of diaphragms 130, the first protruding portions 131 of the plurality of diaphragms 130 can achieve insulation between the first empty foil area 111 and the second electrode 120. This makes it less likely that the first empty foil area 111 and the second electrode 120 will come into contact and short-circuit when the cell 10 is subjected to external force or dropped, thus making the cell 10 safer. Furthermore, the first protruding portion 131 does not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the cell 10.

[0065] In some embodiments, the electrode assembly 100 has a first side and a second side opposite to each other along a first direction X. Along the first direction X, first protrusions 131 of a plurality of diaphragms 130 converge toward the first side and connect.

[0066] By causing the first protruding portions 131 of the plurality of diaphragms 130 to converge toward the first side and connect along the first direction X, the connection method of the first protruding portions 131 of the plurality of diaphragms 130 is simple and easy to operate.

[0067] In some embodiments, the plurality of diaphragms 130 includes a first diaphragm 130a located on the second side, the width of the first extended portion 131 of the first diaphragm 130a along the third direction Z is W1, and the thickness of the electrode assembly 100 is H1, satisfying W1≥H1. For example, W1 can be H1, 1.1*H1, or 1.3*H1, etc.

[0068] Wherein, the width of the first extended portion 131 along the third direction Z is the width of the first extended portion 131 when it is in the extended state (i.e. before it is retracted).

[0069] By ensuring that the width W1 of the first extended portion 131 of the first diaphragm 130a along the third direction Z and the thickness H1 of the electrode assembly 100 satisfy W1≥H1, the first extended portion 131 of the first diaphragm 130a can extend to the first side of the electrode assembly 100, so that the first extended portions 131 of the plurality of diaphragms 130 can be connected on the first side of the electrode assembly 100, thereby facilitating the fabrication of the battery cell 10.

[0070] In some embodiments, the width of the first protruding portion 131 of the diaphragm 130 along the third direction Z is greater than or equal to the distance of the diaphragm 130 along the first direction X to the first side. For example, the width of the first protruding portion 131 of the diaphragm 120 located in the middle of the electrode assembly along the first direction X is greater than or equal to H1 / 2 along the third direction Z.

[0071] By making the width of the first extended portion 131 of the separator 130 along the third direction Z greater than or equal to the distance of the separator 130 along the first direction X to the first side, the first extended portions 131 of the plurality of separators 130 can all extend to the first side of the electrode assembly 100, so that the first extended portions 131 of the plurality of separators 130 can be connected to the first side of the electrode assembly 100, thereby facilitating the fabrication of the cell 10.

[0072] In some embodiments, the plurality of diaphragms 130 includes a first diaphragm 130a located on the second side, wherein the width of the first extended portion 131 of the first diaphragm 130a along the third direction Z is W1, satisfying W1≥2mm. For example, W1 can be 2mm, 2.1mm, or 2.3mm, etc.

[0073] By ensuring that the width W1 of the first protruding portion 131 of the first diaphragm 130a along the third direction Z satisfies W1≥2mm, the first protruding portion 131 of the first diaphragm 130a can extend to the first side of the electrode assembly 100, so that the first protruding portions 131 of the plurality of diaphragms 130 can be connected to the first side of the electrode assembly 100.

[0074] In some embodiments, the plurality of diaphragms 130 includes a second diaphragm 130b located on a first side, wherein the width of the first protruding portion 131 of the second diaphragm 130b along the third direction Z is W2, satisfying W2 ≥ 0.2 mm. For example, W2 can be 0.2 mm, 0.25 mm, or 0.3 mm, etc.

[0075] By ensuring that the width W2 of the first extended portion 131 of the second diaphragm 130b along the third direction Z satisfies W2≥0.2mm, it is easy for the first extended portion 131 of the second diaphragm 130b to be connected to the first extended portion 131 of other diaphragms 130, resulting in a larger connection area and higher connection reliability.

[0076] In some embodiments, the distance from the diaphragm 130 to the first side along the first direction X is S, and the width of the first protruding portion 131 of the diaphragm 130 along the third direction Z is greater than or equal to S+0.2mm. For example, the width of the first protruding portion 131 of the diaphragm 130 along the third direction Z is S+0.2mm, S+0.25mm, or S+0.3mm, etc.

[0077] By making the width of the first extended portion 131 of the separator 130 in the third direction Z greater than or equal to S+0.2mm, the first extended portions 131 of the plurality of separators 130 can all extend to the first side of the electrode assembly 100, and facilitate the connection of the first extended portions 131 of the plurality of separators 130 to the first side of the electrode assembly 100, thereby facilitating the fabrication of the cell 10.

[0078] In some embodiments, the first extensions 131 of a plurality of diaphragms 130 are connected to form a connecting portion, and when viewed along the third direction Z, there is a gap between the connecting portion and the first empty foil area 111.

[0079] By ensuring that there is a gap between the connecting part and the first empty foil area 111 when viewed along the third direction Z, the possibility of interference between the connecting part and the first empty foil area 111 can be reduced, which facilitates the subsequent processing of the first empty foil area 111. Furthermore, it can reduce the possibility of the first protruding part 131 of the multiple diaphragms 130 separating due to interference between the connecting part and other components. This further reduces the possibility of short circuit between the first empty foil area 111 and the second electrode 120, resulting in higher safety of the battery cell 10.

[0080] In some embodiments, the first protruding portions 131 of the plurality of diaphragms 130 converge toward the center and connect in a first direction X.

[0081] The first extended portion 131 of this application means that the first extended portion 131 is pressed together in the first direction X.

[0082] By having the first protruding portions 131 of the multiple diaphragms 130 converge and connect towards the center in the first direction X, the connection method of the first protruding portions 131 of the multiple diaphragms 130 is simpler and easier to operate. Furthermore, the widths of the first protruding portions 131 of the first diaphragm 130a on the second side and the first protruding portions 131 of the second diaphragm 130b on the first side are both smaller. This reduces the possibility of interference between the first protruding portions 131 of the multiple diaphragms 130 and the first empty foil area 111 during connection, further facilitating the connection of the first protruding portions 131 of the multiple diaphragms 130.

[0083] In some embodiments, the first overhangs 131 of the plurality of diaphragms 130 are heat-fused together.

[0084] Currently, in battery cells where tab insulation is achieved using adhesive tape, the adhesive tape is layered with the tab along a first direction. By attaching two sheets of adhesive tape to each side of the tab along the first direction, the two sheets adhere to each other on both sides of the tab along a third direction, thus covering the tab and insulating it from the electrode. However, after the adhesive tape is soaked in electrolyte, its adhesion decreases, making it prone to failure and separation at the joint, resulting in exposed tabs and a significant risk of short circuits between the tabs and the electrode.

[0085] In this application, by thermally bonding the first protruding portions 131 of multiple separators 130 together, the first protruding portions 131 of multiple separators 130 are integrated, which reduces the possibility of the first protruding portions 131 of multiple separators 130 separating after being immersed in electrolyte. This allows the first protruding portions 131 of multiple separators 130 to maintain insulation from the first empty foil area 111 and the second electrode 120, further reducing the possibility of short circuit between the first empty foil area 111 and the second electrode 120, thus making the cell 10 safer.

[0086] In some embodiments, when the diaphragm 130 is prepared, the width of the first protruding portion 131 of the diaphragm 130 can be set to be large. For example, the width of the first protruding portion 131 of each diaphragm 130 is greater than the thickness of the electrode assembly 100. After the first protruding portions 131 of multiple diaphragms 130 are gathered together and heat-fused together, a connecting portion is formed. The connecting portion is cut so that there is a gap between the connecting portion and the first empty foil area 111 along the third direction Z.

[0087] In other embodiments, the diaphragm 130 can also be prepared according to the required width of the first protruding portion 131 of each diaphragm layer 130 during preparation. For example, for the first diaphragm 130a located on the second side of the electrode assembly 100, the width of the first protruding portion 131 of the first diaphragm 130a is greater than or equal to the thickness of the electrode assembly 100. For the second diaphragm 130b located on the first side of the electrode assembly 100, the width of the first protruding portion 131 of the second diaphragm 130b is less than the distance between the first empty foil area 111 and the second electrode 120 along the third direction Z. After the first protruding portions 131 of the multiple diaphragms 130 are gathered and thermally bonded, a connecting portion is formed, so that there is a gap between the connecting portion and the first empty foil area 111 along the third direction Z.

[0088] In some embodiments, the first empty foil area 111 is located at the first corner of the first electrode 110, and the first notch 121 is located at the second corner of the second electrode 120.

[0089] By positioning the first empty foil region 111 at the first corner of the first electrode 110 and the first notch 121 at the second corner of the second electrode 120, it is easier to prepare the first notch 121 and the first empty foil region 111, and it is also easier to bring out the first empty foil region 111.

[0090] In this application, the term "corner position" refers to the position at the apex of the electrode. For example, the first corner position is the corner formed by the edge of the first electrode 110 along the second direction Y and the edge along the third direction X.

[0091] In some embodiments, the first corner position and the second corner position are two adjacent corner positions of the first pole piece 110.

[0092] By making the first corner and the second corner two adjacent corners of the first electrode 110, the first empty foil area 111 and the second empty foil area 122 can be led out from the same end of the electrode assembly 100, which facilitates the battery cell 10 to be electrically connected to an external device through the first empty foil area 111 and the second empty foil area 122.

[0093] In other embodiments, the first corner and the second corner can be two opposite corners of the first electrode 110. This can be applied to structures where the first empty foil area 111 and the second empty foil area 122 need to be led out from opposite ends of the cell 10.

[0094] See Figures 4 to 6 and Figure 10. Figure 10 is a partially enlarged structural diagram of point C in the battery cell in Figure 6.

[0095] In some embodiments, the second electrode 120 has a second empty foil region 122 located at the third corner, and the first electrode 110 has a second notch 112 located at the fourth corner. Along the first direction X, the second empty foil region 122 and the second notch 112 at least partially overlap.

[0096] By ensuring that the second empty foil region 122 at least partially overlaps with the second notch 112 along the first direction X, the volume of the second empty foil region 122 protruding from the electrode assembly 100 can be reduced. This results in a smaller gap space reserved between the electrode assembly 100 and the outer casing for accommodating the second empty foil region 122, which is beneficial for improving the energy density of the battery cell 10. Furthermore, when the battery cell 10 is subjected to external force, the possibility of the electrode assembly 100 shaking relative to the outer casing is smaller, and the possibility of the second empty foil region 122 short-circuiting with the first electrode 110 is also smaller, which can reduce the risk of thermal runaway of the battery cell 10.

[0097] By positioning the second empty foil region 122 at the triangular position of the second electrode 120 and the second notch 112 at the fourth corner position of the first electrode 110, it is easier to prepare the second notch 112 and the second empty foil region 122, and it is also easier to lead out the second empty foil region 122.

[0098] In some embodiments, the second notch 112 has a third edge 1121 and a fourth edge 1122, the third edge 1121 being connected to the fourth edge 1122, and the second empty foil region 122 extending beyond the third edge 1121 along the second direction Y. The diaphragm 130 has a second extension portion 132 extending beyond the fourth edge 1122 along the third direction Z, and the second extension portions 132 of a plurality of diaphragms 130 are connected.

[0099] By making the diaphragm 130 have a second protruding portion 132 extending beyond the fourth edge 1122 along the third direction Z, and connecting the second protruding portions 132 of the plurality of diaphragms 130, the second protruding portions 132 of the plurality of diaphragms 130 can achieve insulation between the second empty foil area 122 and the first electrode 110. This makes it less likely that the second empty foil area 122 will come into contact with the first electrode 110 and short-circuit when the cell 10 is subjected to external force or dropped, thus making the cell 10 safer. Furthermore, the second protruding portion 132 does not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the cell 10.

[0100] Referring to Figures 3 and 11, Figure 11 is a schematic diagram of the structure of the separator of the battery cell provided in some embodiments of this application.

[0101] In some embodiments, the diaphragm 130 has a third notch 133 and a fourth notch 134, and along the first direction X, the first empty foil region 111 at least partially overlaps with the third notch 133, and the second empty foil region 122 at least partially overlaps with the fourth notch 134.

[0102] By making the diaphragm 130 have a third notch 133 and a fourth notch 134, along the first direction X, the first empty foil region 111 at least partially overlaps with the third notch 133, and the second empty foil region 122 at least partially overlaps with the fourth notch 134, so that the third notch 133 can be used to accommodate the first empty foil region 111 and the fourth notch 134 can be used to accommodate the second empty foil region 122, which facilitates the connection of multiple first empty foil regions 111 and multiple second empty foil regions 122 respectively.

[0103] In some embodiments, the first notch 121 and the second empty foil region 122 are located at one end of the second electrode 120 along the second direction Y, and the first notch 121 and the second empty foil region 122 are spaced apart along the third direction Z.

[0104] By positioning the first notch 121 and the second empty foil area 122 at one end of the second electrode 120 along the second direction Y, the first empty foil area 111 and the second empty foil area 122 can be led out from one end of the electrode assembly 110 along the second direction Y, facilitating electrical connection of the battery cell 10 to an external device via the first empty foil area 111 and the second empty foil area 122. The first notch 121 and the second empty foil area 122 are spaced apart along the third direction Z, reducing the possibility of short circuits between the first empty foil area 111 and the second electrode 120, and between the second empty foil area 122 and the first electrode 110, thereby reducing the possibility of thermal runaway of the battery cell 10 and improving its safety.

[0105] In some embodiments, the third and fourth corner positions are two adjacent corner positions of the second pole piece 120.

[0106] By making the third and fourth corner positions two adjacent corner positions of the second electrode 120, the first empty foil area 111 and the second empty foil area 122 can be led out from the same end of the electrode assembly 100, which facilitates the battery cell 10 to be electrically connected to an external device through the first empty foil area 111 and the second empty foil area 122.

[0107] In other embodiments, the third and fourth corner positions can be two opposite corner positions of the second electrode 120. This can be applied to structures where the first empty foil region 111 and the second empty foil region 122 need to be led out from opposite ends of the cell 10.

[0108] In some embodiments, the first electrode 110 is a positive electrode and the second electrode 120 is a negative electrode.

[0109] Referring to Figures 12 and 13, Figure 12 is a schematic diagram of a partial structure of a battery cell provided in some other embodiments of this application from one perspective; Figure 13 is a schematic diagram of the structure of the second electrode of a battery cell provided in some other embodiments of this application.

[0110] In other embodiments, the first notch 121 has a fifth edge 1213, which is spaced apart from the second edge 1212 along a third direction Z, and the first edge 1211 connects the second edge 1212 and the fifth edge 1213. The diaphragm 130 has a third protruding portion 135 extending beyond the fifth edge 1213 along a third direction Z, and the third protruding portions 135 of a plurality of diaphragms 130 are connected.

[0111] By making the diaphragm 130 have a third overhang 135 extending beyond the fifth edge 1213 along the third direction Z, and connecting the third overhang 135 of the plurality of diaphragms 130, the third overhang 135 of the plurality of diaphragms 130 can achieve insulation between the first empty foil area 111 and the second electrode 120. This makes it less likely that the first empty foil area 111 and the second electrode 120 will short-circuit when the cell 10 is subjected to external force or dropped, thus making the cell 10 safer. Furthermore, the third overhang 135 does not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the cell 10.

[0112] Referring to Figures 1 and 2, in some embodiments, the battery cell 10 includes a housing 200 having an accommodating space, and the electrode assembly 100 is disposed in the accommodating space.

[0113] In some embodiments, the housing 200 is a packaging bag, which simplifies the installation of the housing 200 and the electrode assembly 100.

[0114] In other embodiments, the housing 200 can be made of a high-strength material, such as steel, aluminum alloy, or other metallic materials, giving the housing 200 high load-bearing capacity. This makes the housing 200 less prone to deformation or damage due to stress or environmental changes, thereby increasing the reliability of the battery cell 10. The housing 200 can also be made of high-strength non-metallic materials such as carbon fiber or rigid plastic.

[0115] The battery cell includes an electrode assembly 100, a housing 200, and an electrolyte. The housing 200 houses the electrode assembly 100 and the electrolyte. The electrode assembly 100 consists of a positive electrode, a negative electrode, and a separator 130. The battery cell 10 primarily operates by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the portion of the positive current collector without the positive active material layer serves as the positive electrode tab, through which electrical energy is input or output to the positive electrode. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary materials, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the portion of the negative current collector without the negative active material layer serves as the negative electrode tab, through which electrical energy is input or output. The negative current collector can be made of copper, and the negative active material can be made of carbon or silicon, etc. The separator can be made of polypropylene (PP) or polyethylene (PE), etc. The electrolyte can include organic solvents, lithium salts, etc.

[0116] In some embodiments, the battery cell 10 further includes a first electrical connector 310, which is connected to a first empty foil area 111 and extends out of the housing 200.

[0117] By connecting the first electrical connector 310 to the first empty foil area 111, and extending the first electrical connector 310 out of the housing 200, it is possible to facilitate the electrical connection of external devices to the electrode assembly 100 through the first electrical connector 310.

[0118] In some embodiments, the battery cell 10 further includes a second electrical connector 320, which is connected to the second empty foil area 122 and extends out of the housing 200.

[0119] By connecting the second electrical connector 320 to the second empty foil area 122, and extending the second electrical connector 320 out of the housing 200, it is possible to facilitate the electrical connection of external devices to the electrode assembly 100 through the second electrical connector 320.

[0120] In some embodiments, the battery cell 10 further includes a first seal 330 disposed between the first electrical connector 310 and the housing 200.

[0121] By providing a first seal 330 between the first electrical connector 310 and the housing 200, the sealing performance between the first electrical connector 310 and the housing 200 can be improved, and the sealing performance of the battery cell 10 can be improved.

[0122] In some embodiments, the battery cell 10 further includes a second seal 340 disposed between the second electrical connector 320 and the housing 200.

[0123] By providing a second seal 340 between the second electrical connector 320 and the housing 200, the sealing performance between the second electrical connector 320 and the housing 200 is improved, and the sealing performance of the battery cell 10 is also improved.

[0124] This application provides an electrical device, including a battery cell 10 according to any of the above schemes, the battery cell 10 being used to provide electrical energy to the electrical device.

[0125] The electrical equipment can be any of the aforementioned devices or systems using battery cell 10.

[0126] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0127] 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. 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 in that, The device includes an electrode assembly, which is a stacked structure. The electrode assembly includes a plurality of first electrodes, a plurality of second electrodes, and a plurality of diaphragms. The first electrodes and the second electrodes have opposite polarities. The plurality of first electrodes and the plurality of second electrodes are stacked along a first direction. The plurality of diaphragms are respectively disposed between the first electrodes and the second electrodes. Each first electrode has a first empty foil region, and each second electrode has a first notch, wherein at least a portion of the first empty foil region is exposed to the first notch along the first direction; The first notch has a first edge and a second edge, the first edge being connected to the second edge, and the first empty foil area extending beyond the first edge along a second direction; The diaphragm has a first protruding portion extending beyond the second edge in a third direction, and the first protruding portions of a plurality of diaphragms are connected. When viewed in the first direction, the first protruding portion is located within the first notch. The first direction is the thickness direction of the electrode assembly, and the first direction, the second direction, and the third direction are perpendicular to each other.

2. The battery cell according to claim 1, characterized in that, The electrode assembly has a first side and a second side that are opposite each other along the first direction; Along the first direction, the first extended portions of the plurality of diaphragms converge toward the first side and connect.

3. The battery cell according to claim 2, characterized in that, The plurality of diaphragms includes a first diaphragm located on the second side, the width of the first extended portion of the first diaphragm along the third direction being W1, and the thickness of the electrode assembly being H1, such that W1≥H1.

4. The battery cell according to claim 2, characterized in that, The plurality of diaphragms includes a first diaphragm located on the second side, wherein the width of the first extended portion of the first diaphragm along the third direction is W1, satisfying W1≥2mm.

5. The battery cell according to claim 2, characterized in that, The plurality of diaphragms includes a second diaphragm located on the first side, wherein the width of the first extended portion of the second diaphragm along the third direction is W2, satisfying W2≥0.2mm.

6. The battery cell according to claim 1, characterized in that, The first extended portions of the plurality of diaphragms are connected to form a connecting portion, and when viewed along the third direction, there is a gap between the connecting portion and the first empty foil area.

7. The battery cell according to claim 1, characterized in that, The first extended portions of the plurality of diaphragms converge toward the center and connect in the first direction.

8. The battery cell according to claim 1, characterized in that, The first extended portions of the plurality of diaphragms are heat-fused together.

9. The battery cell according to claim 1, characterized in that, The first empty foil area is located at the first corner of the first electrode, and the first notch is located at the second corner of the second electrode.

10. The battery cell according to claim 9, characterized in that, The second electrode has a second empty foil area located at the third corner, and the first electrode has a second notch located at the fourth corner. Along the first direction, the second empty foil area and the second notch at least partially overlap. The second notch has a third edge and a fourth edge, the third edge being connected to the fourth edge, and the second empty foil area extending beyond the third edge along the second direction; The diaphragm has a second protruding portion extending beyond the fourth edge in a third direction, and the second protruding portions of a plurality of the diaphragms are connected.

11. The battery cell according to claim 1, characterized in that, The first notch has a fifth edge, which is spaced apart from the second edge along the third direction, and the first edge connects the second edge and the fifth edge; The diaphragm has a third protruding portion extending beyond the fifth edge in a third direction, and the third protruding portions of a plurality of diaphragms are connected.

12. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-11, the battery cell being used to provide electrical energy.

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