Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment, the battery cell comprises a packaging bag, an electrode assembly and a first electric connector, and the packaging bag comprises a main body part and a sealing part. The electrode assembly is accommodated in the main body part, the electrode assembly comprises an electrode body and a plurality of first tabs, the plurality of first tabs are stacked and folded to form a first folded part, and the thickness H of the battery cell is less than or equal to 2.5 mm. The first electric connecting piece comprises a first connecting part, a first bending part and a first extending part, the first connecting part is connected with the first folding part, the first extending part extends out of the packaging bag from the sealing part, and the first bending part is connected with the first connecting part and the first extending part. In the thickness direction of the electrode assembly, the projection of the first extending part and the projection of the first connecting part are at least partially overlapped. And the first bending part can provide a buffering effect to reduce the possibility that the first tab is broken or the first electric connecting piece is separated from the first tab, so that the risk of failure or short circuit of the battery cell is reduced, and the safety and reliability of the battery cell can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell and an electrical device. Background Art

[0002] With the rapid development of electronic information technology, various electronic devices are also moving towards intelligence and multi-functions, and the requirements for battery safety and reliability are becoming higher and higher.

[0003] At present, in order to improve the current capacity of the battery cell, multiple tabs are set in the battery cell. After the multiple tabs are stacked along the thickness direction of the battery cell, they are connected to the electrical connector. The bending of the tabs will increase the thickness of the battery cell. Therefore, in ultra-thin batteries, the tabs are not bent again after being folded, and they are directly extended out of the packaging bag of the battery cell after being connected to the electrical connector. However, in this structure, the connection between the electrical connector and the tab is in a tight state, and it is easy to cause the tab to break or the electrical connector to fall off after being stressed, affecting the safety and reliability of the battery cell. Summary of the invention

[0004] The present application provides a battery cell and electrical equipment, which can improve the safety and reliability of the battery cell.

[0005] In a first aspect, the present application provides a battery cell, the battery cell comprising a packaging bag, an electrode assembly and a first electrical connector, the packaging bag comprising a main body and a sealing portion. The electrode assembly is accommodated in the main body, the electrode assembly comprises an electrode body and a plurality of first pole ears, the plurality of first pole ears are stacked and gathered to form a first gathered portion, and the thickness H of the battery cell is less than or equal to 2.5 mm. The first electrical connector comprises a first connecting portion, a first bending portion and a first extending portion, the first connecting portion is connected to the first gathered portion, the first extending portion extends out of the packaging bag from the sealing portion, and the first bending portion connects the first connecting portion and the first extending portion. Wherein, along the thickness direction of the electrode assembly, the projection of the first extending portion at least partially overlaps with the projection of the first connecting portion.

[0006] In the above technical solution, the electrode assembly is accommodated in the main body of the packaging bag, so that the packaging bag can play a protective role on the electrode assembly. By making a plurality of first tabs stacked and gathered to form a first gathered portion, the first electrical connector includes a first connection portion, a first bending portion and a first extension portion, the first connection portion is connected to the first gathered portion, and the first extension portion extends out of the packaging bag from the sealing portion, so that when the battery cell is subjected to external force, the first electrical connector is directly subjected to force, while the first tab is not directly subjected to force, and the first electrical connector can play a buffering role, reducing the possibility that the first tab pulls the electrode body and causes damage to the electrode body. Further, the first bending portion connects the first connection portion and the first extension portion, so that when the first extension portion extending out of the packaging bag is subjected to force, the first bending portion can provide a buffering effect, thereby making the force acting on the first connection portion smaller, and can reduce the possibility of the first tab breaking or the first electrical connector being separated from the first tab when the battery cell is subjected to force, thereby reducing the risk of battery cell failure or short circuit, and can improve the safety and reliability of the battery cell. By adopting this solution, the thickness H of the battery cell can be less than or equal to 2.5 mm. By making the projection of the first extension portion and the projection of the first connection portion at least partially overlap along the thickness direction of the electrode assembly, that is, the first extension portion and the first connection portion can be stacked in the thickness direction of the electrode assembly, the space occupied by the first electrical connector in the thickness direction of the electrode assembly can be smaller and does not exceed the electrode body, which can reduce the space occupied by the electrode assembly in its thickness direction, which is beneficial to improving the energy density of the battery cell.

[0007] In some embodiments of the present application, the plurality of first electrode tabs are gathered along the thickness direction of the electrode assembly to form a first gathered portion, and portions of the plurality of first electrode tabs located in the first gathered portion are stacked along the thickness direction of the electrode assembly.

[0008] In the above technical solution, since the thickness of the battery cell is relatively small, a first gathered portion is formed by gathering a plurality of first pole ears along the thickness direction of the electrode assembly, and portions of the plurality of first pole ears located in the first gathered portion are stacked along the thickness direction of the electrode assembly. The first gathered portion formed after the plurality of first pole ears are gathered can extend in a direction perpendicular to the thickness direction of the electrode assembly, and the first gathered portion does not exceed the electrode body in the thickness direction of the electrode assembly, thereby reducing the space occupied by the electrode assembly in its thickness direction, which is beneficial to improving the energy density of the battery cell.

[0009] In some embodiments of the present application, along the thickness direction of the electrode assembly, the first connecting portion is located between the first gathered portion and the first extending portion.

[0010] In the above technical solution, the first connecting portion is located between the first gathering portion and the first extending portion along the thickness direction of the electrode assembly, that is, the first gathering portion, the first connecting portion and the first extending portion can be stacked in the thickness direction of the electrode assembly. This allows the first electrical connector and the first gathering portion to occupy a smaller space in the thickness direction of the electrode assembly and not exceed the electrode body, thereby reducing the space occupied by the electrode assembly in its thickness direction, which is beneficial to improving the energy density of the battery cell.

[0011] In some embodiments of the present application, the first extension portion extends out of the packaging bag along a first direction. Along the first direction, an end of the first extension portion close to the electrode body and an end of the first connection portion close to the electrode body are connected through a first bending portion.

[0012] In the above technical solution, by connecting one end of the first extension portion close to the electrode body and one end of the first connection portion close to the electrode body along the first direction through the first bending portion, when the part of the first extension portion extending out of the packaging bag is subjected to force, the first bending portion can provide a buffering effect, thereby making the force acting on the first connection portion smaller, and reducing the possibility of the first pole ear breaking or the first electrical connector detaching from the first pole ear when the battery cell is subjected to force, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell.

[0013] In some embodiments of the present application, along the thickness direction of the electrode assembly, the height of the first bent portion is T, and the thickness of the first electrical connector is h, satisfying 3×h≤T≤H.

[0014] In the above technical solution, when T is greater than or equal to 3×h, the buffer distance of the first bent portion is longer, the risk of the first electrical connector being broken due to force is lower, the risk of battery cell failure or short circuit is reduced, and the safety and reliability of the battery cell can be improved; when T is less than or equal to H, the first bent portion does not exceed the main body of the packaging bag in the thickness direction of the electrode assembly, and the impact on the energy density of the battery cell is relatively small; therefore, when 3×h≤T≤H, the risk of the first electrical connector being broken due to force can be lowered, the risk of battery cell failure or short circuit is reduced, and the safety and reliability of the battery cell can be improved, and the first bent portion does not exceed the main body of the packaging bag in the thickness direction of the electrode assembly, and the impact on the energy density of the battery cell is relatively small.

[0015] In some embodiments of the present application, the first connecting portion and the first gathered portion are welded to form a welding area. Along the first direction, the length of the welding area is L, satisfying 0.3 mm ≤ L ≤ 0.8 mm.

[0016] In the above technical solution, when L is greater than or equal to 0.3mm, the area of ​​the welding zone can be larger, the connection strength between the first connecting portion and the first gathering portion can be greater, and the possibility of the first electrical connector being forced to separate from the first pole ear is lower, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell; when L is less than or equal to 0.8mm, the space occupied by the welding zone in the first direction can be smaller, which is beneficial to improving the energy density of the battery cell; therefore, when 0.3mm≤L≤0.8mm, the connection strength between the first connecting portion and the first gathering portion can be greater, the possibility of the first electrical connector being forced to separate from the first pole ear is lower, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell, and the space occupied by the welding zone in the first direction can be smaller, which is beneficial to improving the energy density of the battery cell.

[0017] In some embodiments of the present application, along the first direction, the spacing distance between the welding area and the first bending portion is D1, satisfying 0.1 mm≤D1≤0.5 mm.

[0018] In the above technical scheme, when D1 is greater than or equal to 0.1mm, the buffer distance provided by the first bending portion is larger when the first extension portion is subjected to force, thereby further reducing the possibility of the first pole ear breaking or the first electrical connector being detached from the first pole ear, thereby reducing the risk of battery cell failure or short circuit, and further improving the safety and reliability of the battery cell; when D1 is less than or equal to 0.5mm, the risk of the first electrical connector being inserted back into the electrode body when falling can be reduced, which is beneficial to improving the safety and reliability of the battery cell; therefore, when 0.1mm≤D1≤0.5mm, it can reduce the possibility of the first pole ear breaking or the first electrical connector being detached from the first pole ear, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell, and can also reduce the risk of the first electrical connector being inserted back into the electrode body when falling, which is beneficial to improving the safety and reliability of the battery cell.

[0019] In some embodiments of the present application, the first connecting portion and the first gathering portion are welded to form a welding area, and the length of the welding area along the first direction is L; the electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked together, and the spacing distance between the welding area and the negative electrode sheets along the first direction is D2, satisfying 0.15≤L / D2≤3.

[0020] In the above technical scheme, when L / D2 is greater than or equal to 0.15, the length of the welding area between the negative electrode plate and the sealing portion can account for a relatively large proportion, thereby making the connection strength between the first connecting portion and the first gathering portion higher, reducing the possibility of the first electrical connector being separated from the first pole ear; when L / D2 is less than or equal to 3, the portion of the first pole ear that is not welded to the first electrical connector between the negative electrode plate and the sealing portion can account for a relatively large proportion, thereby facilitating the gathering of multiple first pole ears; therefore, when 0.15≤L / D2≤3, both the connection strength between the first connecting portion and the first gathering portion can be made higher, reducing the possibility of the first electrical connector being separated from the first pole ear, and facilitating the gathering of multiple first pole ears.

[0021] In some embodiments of the present application, the first connecting portion and the first gathered portion are welded to form a welding area, and the area of ​​the welding area is S, which satisfies 0.6 mm 2 ≤S≤12mm 2 .

[0022] In the above technical solution, when S is greater than or equal to 0.6 mm 2 , which can make the connection area between the first connecting portion and the first gathered portion larger, the connection strength higher, reduce the possibility of the first electrical connector being separated from the first pole ear, thereby reducing the risk of battery cell failure or short circuit, and can improve the safety and reliability of the battery cell; when S is less than or equal to 12mm 2 , which can make the space occupied by the welding area smaller, so that the packaging bag has more space to accommodate the electrode body, which is beneficial to improve the energy density of the battery cell; therefore, when 0.6mm 2 ≤S≤12mm 2 It can not only make the connection area between the first connecting portion and the first gathered portion larger and the connection strength higher, reduce the possibility of the first electrical connector being separated from the first pole ear, thereby reducing the risk of battery cell failure or short circuit, and can improve the safety and reliability of the battery cell, but also make the space occupied by the welding area smaller, so that the packaging bag has more space for accommodating the electrode body, which is beneficial to improve the energy density of the battery cell.

[0023] In some embodiments of the present application, the first electrical connector further includes a second connecting portion and a second bending portion. Along the thickness direction of the electrode assembly, the first connecting portion, the second connecting portion, and the first extending portion are stacked, the second connecting portion is located between the first connecting portion and the first extending portion, the first bending portion connects the first connecting portion and the second connecting portion, and the second bending portion connects the second connecting portion and the first extending portion.

[0024] In the above technical solution, the first electrical connector also includes a second connecting portion and a second bending portion; along the thickness direction of the electrode assembly, the first connecting portion, the second connecting portion and the first extension portion are stacked, the second connecting portion is located between the first connecting portion and the first extension portion, the first bending portion connects the first connecting portion and the second connecting portion, and the second bending portion connects the second connecting portion and the first extension portion, so that when the first extension portion is subjected to force, the first bending portion, the second connecting portion and the second bending portion can all provide a buffering effect, further making the force acting on the first connecting portion smaller, which can further reduce the possibility of the first pole ear breaking or the first electrical connector detaching from the first pole ear when the battery cell is subjected to force, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell.

[0025] In some embodiments of the present application, the electrode assembly further includes a plurality of second pole tabs, the second pole tabs have opposite polarities to the first pole tabs, and the plurality of second pole tabs are stacked and gathered to form a second gathered portion. The battery cell further includes a second electrical connector, the second electrical connector includes a third connecting portion, a third bending portion, and a second extending portion, the third connecting portion is connected to the second gathered portion, and the third bending portion is connected to the third connecting portion and the second extending portion.

[0026] In the above technical solution, a plurality of second tabs are stacked and gathered to form a second gathered portion. The battery cell also includes a second electrical connector, which includes a third connector, a third bent portion, and a second extension portion, the third connector is connected to the second gathered portion, and the third bent portion is connected to the third connector and the second extension portion, so that when the second extension portion extending out of the packaging bag is subjected to force, the third bent portion can provide a buffering effect, thereby making the force acting on the third connector smaller, which can reduce the possibility of the second tab breaking or the second electrical connector being separated from the second tab when the battery cell is subjected to force, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell.

[0027] In some embodiments of the present application, the electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces stacked together, each first pole piece includes a first coating region and a first pole ear, and along the thickness direction of the electrode assembly, the first pole ears of the plurality of first pole pieces at least partially overlap. Each second pole piece includes a second coating region and a second pole ear, and along the thickness direction of the electrode assembly, the second pole ears of the plurality of second pole pieces at least partially overlap.

[0028] In the above technical solution, by making the first pole tabs of the plurality of first pole sheets at least partially overlap along the thickness direction of the electrode assembly, the plurality of first pole tabs can be easily gathered and connected. By making the second pole tabs of the plurality of second pole sheets at least partially overlap along the thickness direction of the electrode assembly, the plurality of second pole tabs can be easily gathered and connected.

[0029] In some embodiments of the present application, each first pole piece has a first notch, each second pole piece has a second notch, and when viewed along the thickness direction of the electrode assembly, the first notch and the second notch do not overlap. When viewed along the thickness direction of the electrode assembly, the first pole tab at least partially overlaps the second notch. The second pole tab at least partially overlaps the first notch.

[0030] In the above technical solution, by making each first pole piece have a first notch and each second pole piece have a second notch, when observed along the thickness direction of the electrode assembly, the first notch and the second notch do not overlap; when observed along the thickness direction of the electrode assembly, the first pole ear and the second notch at least partially overlap; the second pole ear and the first notch at least partially overlap, which can reduce the possibility of short circuit caused by contact between the first pole ear and the second pole ear; can reduce the volume of the first pole ear and the second pole ear protruding from the electrode body, and the spacing space reserved between the electrode assembly and the packaging bag for accommodating the first pole ear and the second pole ear is reduced, which can improve the energy density of the battery cell.

[0031] In some embodiments of the present application, the first pole piece has a first angular position and a second angular position, the second pole piece has a third angular position and a fourth angular position, the first notch is located at the first angular position of the first pole piece, and the first pole ear is located at the second angular position of the first pole piece. The second notch is located at the third angular position of the second pole piece, and the second pole ear is located at the fourth angular position of the second pole piece.

[0032] In the above technical solution, by making the first notch located at the first angular position of the first pole piece, the first pole ear located at the second angular position of the first pole piece, the second notch located at the third angular position of the second pole piece, and the second pole ear located at the fourth angular position of the second pole piece, it is possible to facilitate the preparation of the first notch, the first pole ear, the second notch, and the second pole ear, and to facilitate the lead-out of the first pole ear and the second pole ear, further reducing the possibility of short circuit between the first pole ear and the second pole piece, and between the second pole ear and the first pole piece.

[0033] In a second aspect, the present application provides an electrical device, which includes a battery cell as described above, and the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can also be obtained based on these drawings.

[0035] Figure 1 A schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0036] Figure 2A three-dimensional schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0037] Figure 3 A three-dimensional schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0038] Figure 4 for Figure 3 A schematic diagram of the partial enlarged structure of the A part of the middle battery cell;

[0039] Figure 5 A schematic structural diagram of a battery cell from one perspective provided in some embodiments of the present application;

[0040] Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure of part of the battery cell along the BB;

[0041] Figure 7 for Figure 6 A schematic diagram of the partial enlarged structure of the C part of the middle cell;

[0042] Figure 8 A schematic diagram of a partially enlarged structure of a battery cell provided in some other embodiments of the present application;

[0043] Fig. 9 for Figure 3 A schematic diagram of the partial enlarged structure at D of the middle cell;

[0044] Fig.10 A three-dimensional schematic diagram of a partial structure of a battery cell provided in some other embodiments of the present application;

[0045] Fig.11 A schematic diagram of the structure of the first pole piece of a battery cell provided in some other embodiments of the present application;

[0046] Fig.12 A schematic diagram of the structure of the second pole piece of a battery cell provided in some other embodiments of the present application.

[0047] Icons: 10-battery cell; 100-packaging bag; 110-main body; 120-sealing part; 200-electrode assembly; 201-electrode body; 210-first pole piece; 211-first pole ear; 211a-first gathering part; 212-first coating area; 213-first notch; 220-second pole piece; 221-second pole ear; 221a-second gathering part; 222-second coating area; 223-second notch; 310-first electrical connector; 311-first connecting part; 3111-welding area; 312-first bending part; 313-first extension part; 314-second connecting part; 315-second bending part; 320-second electrical connector; 321-third connecting part; 322-third bending part; 323-second extension part; X-thickness direction of electrode assembly; Y-first direction; Z-second direction. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0050] The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0051] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0052] In the embodiments of the present application, the same reference numerals represent 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 the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0053] With the development of the new energy industry, battery cells are gradually developing in the direction of high energy density and high power density, so that battery cells can provide higher current and longer battery life. Among them, the overcurrent capacity of the battery cell directly affects the power supply of the battery cell. At present, in order to improve the overcurrent capacity of the battery cell, a plurality of pole ears are provided in the battery cell. The plurality of pole ears are stacked along the thickness direction of the battery cell and connected to the electrical connector, and the electrical connector extends directly out of the packaging bag of the battery cell. The connection between the electrical connector and the pole ear is in a tight state. The electrical connector is pulled by force, which may easily cause the pole ear to break or the electrical connector to fall off, affecting the safety and reliability of the battery cell.

[0054] In order to improve the safety and reliability of the battery cell, the present application provides a battery cell, which includes a packaging bag, an electrode assembly and a first electrical connector, and the packaging bag includes a main body and a sealing portion. The electrode assembly is accommodated in the main body, and the electrode assembly includes an electrode body and a plurality of first pole ears, and the plurality of first pole ears are stacked and gathered to form a first gathered portion, and the thickness of the battery cell is less than or equal to 2.5 mm. The first electrical connector includes a first connecting portion, a first bending portion and a first extending portion, the first connecting portion is connected to the first gathered portion, the first extending portion extends out of the packaging bag from the sealing portion, and the first bending portion connects the first connecting portion and the first extending portion. Wherein, along the thickness direction of the electrode assembly, the projection of the first extending portion at least partially overlaps with the projection of the first connecting portion.

[0055] In the battery cell shell of this structure, the electrode assembly is accommodated in the main body of the packaging bag, so that the packaging bag can play a protective role on the electrode assembly. By stacking and folding a plurality of first tabs to form a first folded portion, the first electrical connector includes a first connection portion, a first bending portion and a first extension portion, the first connection portion is connected to the first folded portion, and the first extension portion extends out of the packaging bag from the sealing portion, so that when the battery cell is subjected to external force, the first electrical connector is directly subjected to force, while the first tab is not directly subjected to force, and the first electrical connector can play a buffering role, reducing the possibility of the first tab pulling the electrode body and causing damage to the electrode body. Furthermore, the first bending portion connects the first connection portion and the first extension portion, so that when the first extension portion extending out of the packaging bag is subjected to force, the first bending portion can provide a buffering effect, thereby making the force acting on the first connection portion smaller, which can reduce the possibility of the first tab breaking or the first electrical connector being separated from the first tab when the battery cell is subjected to force, thereby reducing the risk of battery cell failure or short circuit, and improving the safety and reliability of the battery cell. By making the projection of the first extension portion and the projection of the first connection portion at least partially overlap along the thickness direction of the electrode assembly, that is, the first extension portion and the first connection portion can be stacked in the thickness direction of the electrode assembly, the space occupied by the first electrical connector in the thickness direction of the electrode assembly can be smaller and does not exceed the electrode body, which can reduce the space occupied by the electrode assembly in its thickness direction, which is beneficial to improving the energy density of the battery cell.

[0056] The battery cell provided in the embodiment of the present application can be a secondary battery or a primary battery, for example, a lithium ion battery, a sodium ion battery or a magnesium ion battery, etc., which is not limited in the embodiment of the present application. The electrochemical device can be cylindrical, flat, rectangular or other shapes, etc., which is not limited in the embodiment of the present application.

[0057] The embodiments of the present application provide an electrical device that uses an electrochemical device as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like.

[0058] See also Figures 1 to 4 , Figure 1 A schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application; Figure 2 A three-dimensional schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0059] Figure 3 A three-dimensional schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application; Figure 4 for Figure 3 Schematic diagram of the local enlarged structure at A of the middle battery cell.

[0060] The embodiment of the present application provides a battery cell 10, which includes a packaging bag 100, an electrode assembly 200 and a first electrical connector 310. The packaging bag 100 includes a main body 110 and a sealing portion 120. The electrode assembly 200 is accommodated in the main body 110. The electrode assembly 200 includes an electrode body 201 and a plurality of first pole tabs 211. The plurality of first pole tabs 211 are stacked and gathered to form a first gathered portion 211a. The thickness H of the battery cell 10 is less than or equal to 2.5 mm. The first electrical connector 310 includes a first connecting portion 311, a first bending portion 312 and a first extending portion 313. The first connecting portion 311 is connected to the first gathered portion 211a. The first extending portion 313 extends out of the packaging bag 100 from the sealing portion 120. The first bending portion 312 connects the first connecting portion 311 and the first extending portion 313. In the thickness direction X of the electrode assembly, the projection of the first extending portion 313 at least partially overlaps with the projection of the first connecting portion 311.

[0061] By accommodating the electrode assembly 200 in the main body 110 of the packaging bag 100, the packaging bag 100 can protect the electrode assembly 200. By stacking and folding a plurality of first tabs 211 to form a first folded portion 211a, the first electrical connector 310 includes a first connection portion 311, a first bending portion 312, and a first extension portion 313. The first connection portion 311 is connected to the first folded portion 211a, and the first extension portion 313 extends out of the packaging bag 100 from the sealing portion 120. When the battery cell 10 is subjected to external force, the first electrical connector 310 is directly subjected to the force, while the first tab 211 is not directly subjected to the force. The first electrical connector 310 can play a buffering role, reducing the possibility that the first tab 211 pulls the electrode body 201 and causes damage to the electrode body 201. Furthermore, the first bending portion 312 connects the first connecting portion 311 and the first extending portion 313, so that when the first extending portion 313 extending out of the packaging bag 100 is subjected to force, the first bending portion 312 can provide a buffering effect, thereby making the force acting on the first connecting portion 311 smaller, which can reduce the possibility of the first pole ear 211 breaking or the first electrical connector 310 being detached from the first pole ear 211 when the battery cell 10 is subjected to force, thereby reducing the risk of failure or short circuit of the battery cell 10, and improving the safety and reliability of the battery cell 10. This solution can make the thickness of the battery cell 10 less than or equal to 2.5 mm. By making the projection of the first extension portion 313 at least partially overlap with the projection of the first connection portion 311 along the thickness direction X of the electrode assembly, that is, the first extension portion 313 and the first connection portion 311 can be stacked in the thickness direction X of the electrode assembly, the first electrical connector 310 can occupy a smaller space in the thickness direction X of the electrode assembly and does not exceed the electrode body 201, which can reduce the space occupied by the electrode assembly 200 in its thickness direction, which is beneficial to improving the energy density of the battery cell 10.

[0062] In some embodiments, the packaging bag 100 may be an aluminum-plastic film, a steel-plastic film, or the like.

[0063] In some embodiments, the first connecting portion 311 , the first bending portion 312 and the first extending portion 313 are integrally formed.

[0064] The battery cell 10 also includes an electrolyte, which is contained in the packaging bag 100. The electrode assembly 200 is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell 10 mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode collector, and the part of the positive electrode collector that is not coated with the positive electrode active material layer is used as a positive electrode ear to realize the input or output of electric energy of the positive electrode sheet through the positive electrode ear. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary material or lithium manganese oxide. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode collector, and the part of the negative electrode collector that is not coated with the negative electrode active material layer is used as a negative electrode ear to realize the input or output of electric energy of the negative electrode sheet through the negative electrode ear. The negative electrode current collector may be made of copper, and the negative electrode active material may be made of carbon material or silicon material, etc. The material of the separator may be made of polypropylene (PP) or polyethylene (PE), etc. The electrolyte may include an organic solvent, an electrolyte lithium salt, etc.

[0065] In some embodiments, the electrode assembly 200 may be a laminated structure formed by stacking a negative electrode sheet, a separator, and a positive electrode sheet.

[0066] In other embodiments, the electrode assembly 200 may also be a wound structure formed by winding a negative electrode sheet, a separator, and a positive electrode sheet.

[0067] In some embodiments, the plurality of first electrode tabs 211 are gathered along the thickness direction X of the electrode assembly to form a first gathered portion 211 a , and portions of the plurality of first electrode tabs 211 located in the first gathered portion 211 a are stacked along the thickness direction X of the electrode assembly.

[0068] Since the thickness of the electrode assembly 200 is relatively small, the first gathering portion 211a is formed by gathering the plurality of first pole tabs 211 along the thickness direction X of the electrode assembly. The portions of the plurality of first pole tabs 211 located in the first gathering portion 211a are stacked along the thickness direction X of the electrode assembly. The first gathering portion 211a formed after the plurality of first pole tabs 211 are gathered can extend in a direction perpendicular to the thickness direction X of the electrode assembly. The first gathering portion 211a does not exceed the electrode body 201 in the thickness direction X of the electrode assembly, thereby reducing the space occupied by the electrode assembly 200 in its thickness direction, which is beneficial to improving the energy density of the battery cell 10.

[0069] In some embodiments, after the plurality of first electrode tabs 211 are gathered together, the first gathered portion 211 a may be formed by pressing, welding, or the like.

[0070] In some embodiments, along the thickness direction X of the electrode assembly, the first connection portion 311 is located between the first gathering portion 211 a and the first extending portion 313 .

[0071] By making the first connecting portion 311 located between the first gathering portion 211a and the first extending portion 313 along the thickness direction X of the electrode assembly, that is, the first gathering portion 211a, the first connecting portion 311 and the first extending portion 313 can be stacked in the thickness direction X of the electrode assembly, the space occupied by the first electrical connector 310 and the first gathering portion 211a in the thickness direction X of the electrode assembly can be smaller and do not exceed the electrode body 201, which can reduce the space occupied by the electrode assembly 200 in its thickness direction, which is beneficial to improving the energy density of the battery cell 10.

[0072] In some embodiments, the first extension portion 313 extends out of the packaging bag 100 along the first direction Y. Along the first direction Y, one end of the first extension portion 313 close to the electrode body 201 and one end of the first connection portion 311 close to the electrode body 201 are connected through the first bending portion 312 .

[0073] By connecting one end of the first extension portion 313 close to the electrode body 201 and one end of the first connection portion 311 close to the electrode body 201 along the first direction Y through the first bending portion 312, when the portion of the first extension portion 313 extending out of the packaging bag 100 is subjected to force, the first bending portion 312 can provide a buffering effect, thereby making the force acting on the first connection portion 311 smaller, and reducing the possibility of the first pole tab 211 breaking or the first electrical connector 310 being separated from the first pole tab 211 when the battery cell 10 is subjected to force, thereby reducing the risk of failure or short circuit of the battery cell 10, and improving the safety and reliability of the battery cell 10. Figures 5 to 7 , Figure 5 A schematic structural diagram of a battery cell from one perspective provided in some embodiments of the present application; Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure of part of the battery cell along the BB; Figure 7 for Figure 6 Schematic diagram of the local enlarged structure at C of the medium battery cell.

[0074] In some embodiments, along the thickness direction X of the electrode assembly, the height of the first bent portion 312 is T, and the thickness of the first electrical connector 310 is h, satisfying 3×h≤T≤H. For example, T can be 3×h, H, etc.

[0075] Wherein T includes the thickness of the first connecting portion 311 and the first extending portion 313 , that is, T is the distance along the thickness direction X of the electrode assembly from the first surface of the first connecting portion 311 facing away from the first extending portion 313 to the second surface of the first extending portion 313 facing away from the first connecting portion 311 .

[0076] When T is greater than or equal to 3×h, the buffer distance of the first bending portion 312 is longer, the risk of the first electrical connector 310 being broken by force is lower, the risk of failure or short circuit of the battery cell 10 is reduced, and the safety and reliability of the battery cell 10 can be improved; when T is less than or equal to H, the first bending portion 312 does not exceed the main body 110 of the packaging bag 100 in the thickness direction X of the electrode assembly, and the impact on the energy density of the battery cell 10 is small; therefore, when 3×h≤T≤H, the risk of the first electrical connector 310 being broken by force is lowered, the risk of failure or short circuit of the battery cell 10 is reduced, and the safety and reliability of the battery cell 10 is improved, and the first bending portion 312 does not exceed the main body 110 of the packaging bag 100 in the thickness direction X of the electrode assembly, and the impact on the energy density of the battery cell 10 is small.

[0077] See Table 1, which shows the experimental data of the drop pass rate test of the battery cell.

[0078] Table 1 Drop pass rate test of battery cells

[0079]

[0080] Battery drop pass rate test method:

[0081] 1. Fully charge the finished battery cell, then put it into the fixture and drop it from a height of 1.5m. Each of the six sides of the battery cell should drop 6 times. Each group of 10 batteries should be tested, and each group should be tested 3 times.

[0082] 2. Test the change in the open circuit voltage of the battery cell before and after the drop and whether the battery cell catches fire. The battery cell with voltage drop and fire will be marked as failed.

[0083] According to Table 1, the following conclusions can be drawn:

[0084] 1. Referring to Examples 1-2 and 3-7, when the height T of the first bend is less than 3×h, the buffer distance of the first bend is short, and the risk of the first electrical connector being broken by force is high, resulting in a low drop pass rate of the battery cell. When the height T of the first bend is greater than or equal to 3×h, the buffer distance of the first bend is long, and the risk of the first electrical connector being broken by force is low, resulting in a high drop pass rate of the battery cell, which can improve the safety and reliability of the battery cell.

[0085] 2. Referring to Example 3-7, as the height T of the first bent portion increases, the drop pass rate of the battery cell will increase accordingly.

[0086] In some embodiments, the first connection portion 311 and the first gathered portion 211a are welded to form a welding area 3111. The length of the welding area 3111 along the first direction Y is L, which satisfies 0.3 mm ≤ L ≤ 0.8 mm. For example, L can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm or 0.8 mm.

[0087] When L is greater than or equal to 0.3 mm, the area of ​​the welding area 3111 can be larger, the connection strength between the first connecting portion 311 and the first gathering portion 211a can be greater, and the possibility of the first electrical connector 310 being forced to separate from the first pole ear 211 is lower, thereby reducing the risk of failure or short circuit of the battery cell 10 and improving the safety and reliability of the battery cell 10; when L is less than or equal to 0.8 mm, the space occupied by the welding area 3111 in the first direction Y can be smaller, which is beneficial to improving the energy density of the battery cell 10; therefore, when 0.3 mm≤L≤0.8 mm, the connection strength between the first connecting portion 311 and the first gathering portion 211a can be greater, the possibility of the first electrical connector 310 being forced to separate from the first pole ear 211 is lower, thereby reducing the risk of failure or short circuit of the battery cell 10 and improving the safety and reliability of the battery cell 10, and the space occupied by the welding area 3111 in the first direction Y can be smaller, which is beneficial to improving the energy density of the battery cell 10.

[0088] In some embodiments, along the first direction Y, the distance between the welding area 3111 and the first bending portion 312 is D1, which satisfies 0.1 mm≤D1≤0.5 mm. For example, D1 can be 0.1 mm, 0.4 mm, 1 mm, 3 mm, or 5 mm.

[0089] Among them, along the first direction Y, the spacing distance between the welding area 3111 and the first bending portion 312 is the distance between one end of the welding area 3111 close to the electrode body 201 and the inner surface (the surface facing away from the electrode body 201) of one end of the first bending portion 312 close to the electrode body 201.

[0090] When D1 is greater than or equal to 0.1 mm, when the first extension portion 313 is subjected to force, the buffer distance provided by the first bending portion 312 is relatively large, thereby further reducing the possibility of the first pole ear 211 breaking or the first electrical connector 310 being separated from the first pole ear 211, thereby reducing the risk of failure or short circuit of the battery cell 10, and further improving the safety and reliability of the battery cell 10; when D1 is less than or equal to 0.5 mm, it can reduce the risk of the first electrical connector 310 being inserted into the electrode body 201 when falling, which is beneficial to improving the safety and reliability of the battery cell 10; therefore, when 0.1 mm ≤ D1 ≤ 0.5 mm, it can reduce the possibility of the first pole ear 211 breaking or the first electrical connector 310 being separated from the first pole ear 211, thereby reducing the risk of failure or short circuit of the battery cell 10, and improving the safety and reliability of the battery cell 10, and can also reduce the risk of the first electrical connector 310 being inserted into the electrode body 201 when falling, which is beneficial to improving the safety and reliability of the battery cell 10.

[0091] In some embodiments, the first connection portion 311 is welded with the first gathered portion 211a to form a welding area 3111, and the length of the welding area 3111 along the first direction Y is L. The electrode assembly 200 includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked in a layered manner, and the spacing distance between the welding area 3111 and the negative electrode sheets along the first direction Y is D2, satisfying 0.15≤L / D2≤3. For example, L / D2 may be 0.15, 0.5, 1.3, 2.5, or 3, etc.

[0092] When L / D2 is greater than or equal to 0.15, the length of the welding area 3111 between the negative electrode plate and the sealing portion 120 can be relatively large, thereby increasing the connection strength between the first connecting portion 311 and the first gathering portion 211a, and reducing the possibility of the first electrical connector 310 being separated from the first pole lug 211; when L / D2 is less than or equal to 3, the portion of the first pole lug 211 that is not welded to the first electrical connector 310 between the negative electrode plate and the sealing portion 120 can be relatively large, thereby facilitating the gathering of multiple first pole lugs 211; therefore, when 0.15≤L / D2≤3, both the connection strength between the first connecting portion 311 and the first gathering portion 211a can be relatively high, reducing the possibility of the first electrical connector 310 being separated from the first pole lug 211, and facilitating the gathering of multiple first pole lugs 211.

[0093] In some embodiments, the first connecting portion 311 is welded to the first gathered portion 211a to form a welding area 3111. The area of ​​the welding area 3111 is S, which satisfies the 0.6 mm 2 ≤S≤12mm 2 For example, S can be 0.6 mm 2 , 1.5mm 2 , 5mm 2 , 8mm 2 or 12mm2 wait.

[0094] When S is greater than or equal to 0.6 mm 2 , which can make the connection area between the first connection part 311 and the first gathered part 211a larger, the connection strength higher, and reduce the possibility of the first electrical connector 310 being separated from the first pole ear 211, thereby reducing the risk of failure or short circuit of the battery cell 10, and can improve the safety and reliability of the battery cell 10; when S is less than or equal to 12mm 2 , which can make the space occupied by the welding area 3111 smaller, so that the packaging bag 100 has more space for accommodating the electrode body 201, which is beneficial to improve the energy density of the battery cell 10; therefore, when 0.6mm 2 ≤S≤12mm 2 It can not only make the connection area between the first connecting portion 311 and the first gathering portion 211a larger and the connection strength higher, reduce the possibility of the first electrical connector 310 being separated from the first pole ear 211, thereby reducing the risk of failure or short circuit of the battery cell 10, and can improve the safety and reliability of the battery cell 10, but also make the space occupied by the welding area 3111 smaller, so that the packaging bag 100 has more space for accommodating the electrode body 201, which is beneficial to improve the energy density of the battery cell 10.

[0095] See also Figure 8 , Figure 8 A schematic diagram of a partially enlarged structure of a battery cell provided in some other embodiments of the present application.

[0096] In other embodiments, the first electrical connector 310 further includes a second connection portion 314 and a second bending portion 315. Along the thickness direction X of the electrode assembly, the first connection portion 311, the second connection portion 314, and the first extension portion 313 are stacked, the second connection portion 314 is located between the first connection portion 311 and the first extension portion 313, the first bending portion 312 connects the first connection portion 311 and the second connection portion 314, and the second bending portion 315 connects the second connection portion 314 and the first extension portion 313.

[0097] By making the first electrical connector 310 also include the second connector 314 and the second bending portion 315; along the thickness direction X of the electrode assembly, the first connector 311, the second connector 314, and the first extension portion 313 are stacked, the second connector 314 is located between the first connector 311 and the first extension portion 313, the first bending portion 312 connects the first connector 311 and the second connector 314, and the second bending portion 315 connects the second connector 314 and the first extension portion 313, so that when the first extension portion 313 is subjected to force, the first bending portion 312, the second connector 314, and the second bending portion 315 can all provide a buffering effect, further making the force acting on the first connector 311 smaller, and can further reduce the possibility of the first pole ear 211 breaking or the first electrical connector 310 being separated from the first pole ear 211 when the battery cell 10 is subjected to force, thereby reducing the risk of failure or short circuit of the battery cell 10, and can improve the safety and reliability of the battery cell 10.

[0098] In some embodiments, the first connecting portion 311 , the first bending portion 312 , the second connecting portion 314 , the second bending portion 315 and the first extending portion 313 are integrally formed.

[0099] In other embodiments, the first electrical connector 310 may further include a plurality of second connectors 314 and a second bending portion 315 (not shown in the figure), and along the thickness direction X of the electrode assembly, the first connector 311, the plurality of second connectors 314, and the first extension portion 313 are stacked, the plurality of second connectors 314 are located between the first connector 311 and the first extension portion 313, the first bending portion 312 connects the first connector 311 and the second connector 314, one second bending portion 315 connects one second connector 314 and the first extension portion 313, and the other second bending portions 315 are respectively connected between two adjacent second connectors 314. The buffer distance of the first electrical connector 310 can be further extended, the force acting on the first connector 311 can be further reduced, and the possibility of the first pole tab 211 breaking or the first electrical connector 310 being separated from the first pole tab 211 when the battery cell 10 is subjected to force can be further reduced, thereby reducing the risk of failure or short circuit of the battery cell 10, and improving the safety and reliability of the battery cell 10.

[0100] See also Figure 3 and Fig. 9 , Fig. 9 for Figure 3 Schematic diagram of the local enlarged structure at D of the middle battery cell.

[0101] In some embodiments, the electrode assembly 200 further includes a plurality of second pole tabs 221, the second pole tabs 221 have opposite polarities to the first pole tabs 211, and the plurality of second pole tabs 221 are stacked and gathered to form a second gathered portion 221a. The battery cell 10 further includes a second electrical connector 320, the second electrical connector 320 includes a third connecting portion 321, a third bending portion 322, and a second extending portion 323, the third connecting portion 321 is connected to the second gathered portion 221a, and the third bending portion 322 is connected to the third connecting portion 321 and the second extending portion 323.

[0102] By stacking and gathering a plurality of second pole ears 221 to form a second gathered portion 221a, the battery cell 10 further includes a second electrical connector 320, the second electrical connector 320 includes a third connecting portion 321, a third bending portion 322 and a second extending portion 323, the third connecting portion 321 is connected to the second gathered portion 221a, the third bending portion 322 connects the third connecting portion 321 and the second extending portion 323, so that when the second extending portion 323 extending out of the packaging bag 100 is subjected to force, the third bending portion 322 can provide a buffering effect, thereby making the force acting on the third connecting portion 321 smaller, which can reduce the possibility of the second pole ear 221 breaking or the second electrical connector 320 detaching from the second pole ear 221 when the battery cell 10 is subjected to force, thereby reducing the risk of failure or short circuit of the battery cell 10, and improving the safety and reliability of the battery cell 10.

[0103] See also Figure 3 In some embodiments, the electrode assembly 200 includes a plurality of first pole pieces 210 and a plurality of second pole pieces 220 stacked together, each first pole piece 210 includes a first coating region 212 and a first pole ear 211, and along the thickness direction X of the electrode assembly, the first pole ears 211 of the plurality of first pole pieces 210 at least partially overlap. Each second pole piece 220 includes a second coating region 222 and a second pole ear 221, and along the thickness direction X of the electrode assembly, the second pole ears 221 of the plurality of second pole pieces 220 at least partially overlap.

[0104] By making the first pole tabs 211 of the plurality of first pole sheets 210 at least partially overlap along the thickness direction X of the electrode assembly, it is possible to facilitate the folding and connection of the plurality of first pole tabs 211. By making the second pole tabs 221 of the plurality of second pole sheets 220 at least partially overlap along the thickness direction X of the electrode assembly, it is possible to facilitate the folding and connection of the plurality of second pole tabs 221.

[0105] In some embodiments, the first pole piece 210 is a positive pole piece, and the second pole piece 220 is a negative pole piece.

[0106] In other embodiments, the first pole piece 210 is a negative pole piece, and the second pole piece 220 is a positive pole piece.

[0107] See also Figures 10 to 12 , Fig.10 A three-dimensional schematic diagram of a partial structure of a battery cell provided in some other embodiments of the present application; Fig.11 A schematic diagram of the structure of the first pole piece of a battery cell provided in some other embodiments of the present application; Fig.12 A schematic diagram of the structure of the second pole piece of a battery cell provided in some other embodiments of the present application.

[0108] In other embodiments, each first pole piece 210 has a first notch 213, each second pole piece 220 has a second notch 223, and when viewed along the thickness direction X of the electrode assembly, the first notch 213 and the second notch 223 do not overlap. When viewed along the thickness direction X of the electrode assembly, the first pole tab 211 at least partially overlaps the second notch 223. The second pole tab 221 at least partially overlaps the first notch 213.

[0109] By making each first pole piece 210 have a first notch 213, and each second pole piece 220 have a second notch 223, when observed along the thickness direction X of the electrode assembly, the first notch 213 and the second notch 223 do not overlap; when observed along the thickness direction X of the electrode assembly, the first pole ear 211 and the second notch 223 at least partially overlap; the second pole ear 221 and the first notch 213 at least partially overlap, which can reduce the possibility of short circuit caused by contact between the first pole ear 211 and the second pole ear 221; the volume of the first pole ear 211 and the second pole ear 221 protruding from the electrode body 201 can be reduced, and the spacing space reserved between the electrode assembly 200 and the packaging bag 100 for accommodating the first pole ear 211 and the second pole ear 221 is reduced, which can improve the energy density of the battery cell 10.

[0110] In some embodiments, the first electrode tab 211 and the first notch 213 are arranged at intervals along the second direction Z, and the second electrode tab 221 and the second notch 223 are arranged at intervals along the second direction Z.

[0111] The thickness direction X, the first direction Y, and the second direction Z of the electrode assembly are perpendicular to each other.

[0112] In other embodiments, the first pole piece 210 has a first angular position and a second angular position, the second pole piece 220 has a third angular position and a fourth angular position, the first notch 213 is located at the first angular position of the first pole piece 210, and the first pole ear 211 is located at the second angular position of the first pole piece 210. The second notch 223 is located at the third angular position of the second pole piece 220, and the second pole ear 221 is located at the fourth angular position of the second pole piece 220.

[0113] By locating the first notch 213 at the first angular position of the first pole piece 210, the first pole ear 211 at the second angular position of the first pole piece 210, the second notch 223 at the third angular position of the second pole piece 220, and the second pole ear 221 at the fourth angular position of the second pole piece 220, it is possible to facilitate the preparation of the first notch 213, the first pole ear 211, the second notch 223, and the second pole ear 221, and to facilitate the lead-out of the first pole ear 211 and the second pole ear 221, thereby further reducing the possibility of short circuit between the first pole ear 211 and the second pole piece 220, and between the second pole ear 221 and the first pole piece 210.

[0114] The angular position in this application refers to the position at the top corner of the pole piece.

[0115] An embodiment of the present application provides an electrical device, comprising a battery cell 10 according to any of the above solutions, and the battery cell 10 is used to provide electrical energy to the electrical device.

[0116] The electrical device may be any of the aforementioned devices or systems using the battery cell 10 .

[0117] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0118] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: A packaging bag, comprising a main body and a sealing portion; An electrode assembly is accommodated in the main body, the electrode assembly comprises an electrode body and a plurality of first pole tabs, the plurality of first pole tabs are stacked and gathered to form a first gathered portion, and the thickness H of the battery core is less than or equal to 2.5 mm; A first electrical connector, comprising a first connecting portion, a first bending portion and a first extending portion, wherein the first connecting portion is connected to the first gathering portion, the first extending portion extends from the sealing portion to the packaging bag, and the first bending portion connects the first connecting portion and the first extending portion; Wherein, along the thickness direction of the electrode assembly, the projection of the first extension portion at least partially overlaps with the projection of the first connection portion.

2. The battery cell according to claim 1, characterized in that: The first electrode tabs are gathered together along the thickness direction of the electrode assembly to form the first gathered portion, and portions of the first electrode tabs located in the first gathered portion are stacked along the thickness direction of the electrode assembly.

3. The battery cell according to claim 2, characterized in that: Along the thickness direction of the electrode assembly, the first connecting portion is located between the first gathering portion and the first extending portion.

4. The battery cell according to claim 2, characterized in that: The first extension portion extends out of the packaging bag along a first direction; Along the first direction, one end of the first extension portion close to the electrode body and one end of the first connection portion close to the electrode body are connected through the first bending portion.

5. The battery cell according to claim 1, characterized in that: Along the thickness direction of the electrode assembly, the height of the first bent portion is T, and the thickness of the first electrical connector is h, satisfying 3×h≤T≤H.

6. The battery cell according to claim 4, characterized in that: The first connecting portion and the first gathered portion are welded to form a welding area. Along the first direction, the length of the welding area is L, satisfying 0.3 mm≤L≤0.8 mm.

7. The battery cell according to claim 6, characterized in that: Along the first direction, the spacing distance between the welding area and the first bending portion is D1, which satisfies 0.1 mm≤D1≤0.5 mm.

8. The battery cell according to claim 4, characterized in that: The first connecting portion and the first gathering portion are welded to form a welding area, and along the first direction, the length of the welding area is L; the electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked together, and along the first direction, the spacing distance between the welding area and the negative electrode sheet is D2, satisfying 0.15≤L / D2≤3.

9. The battery cell according to claim 4, characterized in that: The first connecting portion and the first gathered portion are welded to form a welding area, and the area of ​​the welding area is S, which satisfies 0.6mm 2 ≤S≤12mm 2 .

10. The battery cell according to claim 2, characterized in that: The first electrical connector also includes a second connecting portion and a second bending portion; Along the thickness direction of the electrode assembly, the first connecting part, the second connecting part, and the first extension part are stacked, the second connecting part is located between the first connecting part and the first extension part, the first bending part connects the first connecting part and the second connecting part, and the second bending part connects the second connecting part and the first extension part.

11. The battery cell according to claim 1, characterized in that: The electrode assembly further includes a plurality of second electrode tabs, the second electrode tabs have opposite polarities to the first electrode tabs, and the plurality of second electrode tabs are stacked and gathered to form a second gathered portion; The battery cell further includes a second electrical connector, which includes a third connecting portion, a third bending portion and a second extending portion, wherein the third connecting portion is connected to the second gathering portion, and the third bending portion connects the third connecting portion and the second extending portion.

12. The battery cell according to claim 11, characterized in that: The electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces that are stacked, each of the first pole pieces includes a first coating area and a first pole ear, and along the thickness direction of the electrode assembly, the first pole ears of the plurality of first pole pieces at least partially overlap; each of the second pole pieces includes a second coating area and a second pole ear, and along the thickness direction of the electrode assembly, the second pole ears of the plurality of second pole pieces at least partially overlap.

13. The battery cell according to claim 12, characterized in that: Each of the first pole pieces has a first notch, each of the second pole pieces has a second notch, and when viewed along the thickness direction of the electrode assembly, the first notch and the second notch do not overlap; Observed along the thickness direction of the electrode assembly, the first electrode tab at least partially overlaps with the second notch; and the second electrode tab at least partially overlaps with the first notch.

14. The battery cell according to claim 13, characterized in that: The first pole piece has a first angular position and a second angular position, the second pole piece has a third angular position and a fourth angular position, the first notch is located at the first angular position of the first pole piece, and the first pole lug is located at the second angular position of the first pole piece; The second notch is located at the third corner position of the second pole piece, and the second pole tab is located at the fourth corner position of the second pole piece.

15. An electrical equipment, characterized in that: The electrical device comprises the battery cell according to any one of claims 1 to 14, and the battery cell is used to provide electrical energy.

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