Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment, the battery cell comprises an electrode assembly, the electrode assembly comprises a first pole piece group, a second pole piece group, a first pole piece connecting part and a second pole piece connecting part, the first pole piece group and the second pole piece group are laminated along a first direction, and the size of the first pole piece group along a second direction is larger than that of the second pole piece group along the second direction. The first pole piece group comprises a first positive pole piece and a first negative pole piece; and the second pole piece group comprises a second positive pole piece and a second negative pole piece. The first positive current collector of the first positive pole piece, the first pole piece connecting part and the second positive current collector of the second positive pole piece are integrally formed. And the first negative current collector of the first negative pole piece, the second pole piece connecting part and the second negative current collector of the second negative pole piece are integrally formed. The positive pole lug and the negative pole lug in the electrode assembly can be arranged at any position, so that the application range of the battery cell is wider, and the relative position between the first pole piece group and the second pole piece group is more stable.

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 developing towards intelligence and multifunctionality, and the energy density requirements for batteries are getting higher and higher. In order to adapt to different electrical equipment, batteries of different shapes need to be used. For example, a battery with steps is composed of stacked electrode groups of various sizes, and multiple electrode groups are electrically connected through tabs, so that the tabs need to be set in the overlapping area of ​​multiple electrode groups, which limits the structure of the battery cell. Summary of the invention

[0003] The present application provides a battery cell and an electrical device, which can expand the application scope of the battery cell.

[0004] In a first aspect, the present application provides a battery cell, the battery cell includes an electrode assembly, the electrode assembly includes a first electrode sheet group and a second electrode sheet group stacked along a first direction, a first electrode sheet connection portion and a second electrode sheet connection portion, the size of the first electrode sheet group along the second direction is greater than the size of the second electrode sheet group along the second direction, and the first direction is perpendicular to the second direction. The first electrode sheet group includes a first positive electrode sheet and a first negative electrode sheet stacked along the first direction, the first positive electrode sheet includes a first positive electrode current collector, and the first negative electrode sheet includes a first negative electrode current collector. The second electrode sheet group includes a second positive electrode sheet and a second negative electrode sheet stacked along the first direction, the second positive electrode sheet includes a second positive electrode current collector, and the second negative electrode sheet includes a second negative electrode current collector. The first electrode sheet connection portion connects the first positive electrode current collector and the second positive electrode current collector, and the first positive electrode current collector, the first electrode sheet connection portion, and the second positive electrode current collector are integrally formed. The second electrode sheet connection portion connects the first negative electrode current collector and the second negative electrode current collector, and the first negative electrode current collector, the second electrode sheet connection portion, and the second negative electrode current collector are integrally formed.

[0005] In the above technical solution, the first electrode sheet group and the second electrode sheet group are stacked along the first direction, the size of the first electrode sheet group along the second direction is larger than the size of the second electrode sheet group along the second direction, and the first direction is perpendicular to the second direction, so that a step is formed on at least one side of the electrode assembly along the second direction, so that when the battery cell is assembled in the battery compartment of the electrical equipment, other components in the battery compartment can be placed at the step, which is beneficial to improve the space utilization of the battery compartment, and further improve the compactness of the internal structure of the electrical equipment. The first electrode sheet connection portion is connected to the first positive current collector and the second positive current collector, and the first positive current collector, the first electrode sheet connection portion, and the second positive current collector are integrally formed; the second electrode sheet connection portion is connected to the first negative current collector and the second negative current collector, and the first negative current collector, the second electrode sheet connection portion, and the second negative current collector are integrally formed, so that the first positive electrode sheet of the first electrode sheet group and the second positive electrode sheet of the second electrode sheet group can be electrically connected through the first electrode sheet connection portion, and the first negative electrode sheet of the first electrode sheet group and the second electrode sheet The second negative electrode sheet of the group can be electrically connected through the second electrode sheet connecting part, so that the positive and negative electrodes of the electrode assembly can be led out through only one of the first electrode sheet group and the second electrode sheet group. The positive electrode tabs and the negative electrode tabs in the electrode assembly can be set at any position, so that the application range of the battery cell is wider, and the relative positions between the first positive electrode sheet and the second positive electrode sheet, and between the first negative electrode sheet and the second negative electrode sheet can be made more stable, reducing the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group, and the reliability of the battery cell is higher.

[0006] In some embodiments of the present application, a first diaphragm is provided between the first negative electrode plate and the first positive electrode plate, and a second diaphragm is provided between the second negative electrode plate and the second positive electrode plate. The electrode assembly includes a first diaphragm connecting portion, the first diaphragm connecting portion connects the first diaphragm and the second diaphragm, and the first diaphragm, the first diaphragm connecting portion, and the second diaphragm are integrally formed. The first diaphragm connecting portion is provided between the first electrode plate connecting portion and the second electrode plate connecting portion.

[0007] In the above technical solution, a first diaphragm is provided between the first negative electrode plate and the first positive electrode plate, so that the first diaphragm plays an isolating and insulating role between the first negative electrode plate and the first positive electrode plate. A second diaphragm is provided between the second negative electrode plate and the second positive electrode plate, so that the second diaphragm plays an isolating and insulating role between the second negative electrode plate and the second positive electrode plate. By making the first diaphragm connecting portion connect the first diaphragm and the second diaphragm, and the first diaphragm, the first diaphragm connecting portion, and the second diaphragm are integrally formed, the relative position between the first diaphragm and the second diaphragm can be made more stable, reducing the possibility of displacement of the second electrode plate group relative to the first electrode plate group, and the reliability of the battery cell is higher. The first diaphragm connecting portion is arranged between the first pole piece connecting portion and the second pole piece connecting portion, so that the first diaphragm connecting portion plays an isolating and insulating role between the first pole piece connecting portion and the second pole piece connecting portion, and after the first pole piece group and the second pole piece group are prepared and formed, the first pole piece connecting portion, the second pole piece connecting portion and the first diaphragm connecting portion are bent once so that the second pole piece group can be stacked on the first pole piece group, which is convenient for the preparation of the electrode assembly.

[0008] In some embodiments of the present application, the first electrode connecting portion connects one side of the first positive electrode collector along the second direction and one side of the second positive electrode collector along the second direction. The second electrode connecting portion connects one side of the first negative electrode collector along the second direction and one side of the second negative electrode collector along the second direction.

[0009] In the above technical solution, by making the first pole piece connecting portion connect one side of the first positive electrode collector along the second direction and one side of the second positive electrode collector along the second direction, and the second pole piece connecting portion connects one side of the first negative electrode collector along the second direction and one side of the second negative electrode collector along the second direction, after the first pole piece group and the second pole piece group are prepared and formed, the first pole piece connecting portion and the second pole piece connecting portion are bent once so that the second pole piece group can be stacked on the first pole piece group, which is convenient for the preparation of the electrode assembly.

[0010] In some embodiments of the present application, along the third direction, the length of the first diaphragm connection portion is greater than or equal to the length of the first pole piece connection portion, and / or the length of the first diaphragm connection portion is greater than or equal to the length of the second pole piece connection portion. The first direction, the second direction and the third direction are perpendicular to each other.

[0011] In the above technical solution, by making the length of the first diaphragm connection part greater than or equal to the length of the first pole piece connection part along the third direction, and / or the length of the first diaphragm connection part greater than or equal to the length of the second pole piece connection part, the first diaphragm connection part can further provide better isolation and insulation effect between the first pole piece connection part and the second pole piece connection part, thereby reducing the possibility of short circuit of the electrode assembly and improving the safety of the battery cell.

[0012] In some embodiments of the present application, along the third direction, the length of the first electrode sheet connection portion is L1, the length of the first positive electrode sheet is L2, and the length of the second positive electrode sheet is L3, satisfying 0.1≤L1 / L2≤1; 0.1≤L1 / L3≤1. The first direction, the second direction, and the third direction are perpendicular to each other.

[0013] In the above technical scheme, when L1 / L2 is greater than or equal to 0.1, and L1 / L3 is greater than or equal to 0.1, the length of the first electrode sheet connection portion can be made larger, so that the connection strength between the first positive electrode collector and the second positive electrode collector is higher, and the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group is further reduced, and the reliability of the battery cell is higher; when L1 / L2 is less than or equal to 1, and L1 / L3 is less than or equal to 1, it is convenient to prepare the first electrode sheet connection portion; therefore, when 0.1≤L1 / L2≤1, 0.1≤L1 / L3≤1, it is possible to make the connection strength between the first positive electrode collector and the second positive electrode collector higher, further reduce the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group, the reliability of the battery cell is higher, and it is convenient to prepare the first electrode sheet connection portion.

[0014] In some embodiments of the present application, the first pole piece connection portion connects one side of the first positive electrode current collector along the third direction and one side of the second positive electrode current collector along the third direction. The second pole piece connection portion is connected to one side of the first negative electrode current collector along the third direction and one side of the second negative electrode current collector along the third direction. The first direction, the second direction and the third direction are perpendicular to each other.

[0015] In the above technical solution, by making the first pole piece connecting portion connect one side of the first positive electrode collector along the third direction and one side of the second positive electrode collector along the third direction, and the second pole piece connecting portion is connected to one side of the first negative electrode collector along the third direction and one side of the second negative electrode collector along the third direction, after the first pole piece group and the second pole piece group are prepared and formed, the first pole piece connecting portion and the second pole piece connecting portion are bent once so that the second pole piece group can be stacked on the first pole piece group, which is convenient for the preparation of the electrode assembly.

[0016] In some embodiments of the present application, along the second direction, the length of the first diaphragm connecting portion is greater than or equal to the length of the first pole piece connecting portion, and / or the length of the first diaphragm connecting portion is greater than or equal to the length of the second pole piece connecting portion.

[0017] In the above technical solution, by making the length of the first diaphragm connection part greater than or equal to the length of the first pole piece connection part along the second direction, and / or the length of the first diaphragm connection part greater than or equal to the length of the second pole piece connection part, the isolation and insulation effect between the first diaphragm connection part and the second pole piece connection part can be further improved, thereby reducing the possibility of short circuit of the electrode assembly and improving the safety of the battery cell.

[0018] In some embodiments of the present application, along the second direction, the width of the first electrode sheet connecting portion is W1, the width of the first positive electrode sheet is W2, and the width of the second positive electrode sheet is W3, satisfying 0.1≤W1 / W2≤1; 0.1≤W1 / W3≤1.

[0019] In the above technical scheme, when W1 / W2 is greater than or equal to 0.1, and W1 / W3 is greater than or equal to 0.1, the width of the first electrode sheet connection portion can be larger, so that the connection strength between the first positive electrode collector and the second positive electrode collector is higher, and the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group is further reduced, and the reliability of the battery cell is higher; when W1 / W2 is less than or equal to 1, and W1 / W3 is less than or equal to 1, it is convenient to prepare the first electrode sheet connection portion; therefore, when 0.1≤W1 / W2≤1, 0.1≤W1 / W3≤1, it is possible to make the connection strength between the first positive electrode collector and the second positive electrode collector higher, further reduce the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group, the reliability of the battery cell is higher, and it is convenient to prepare the first electrode sheet connection portion.

[0020] In some embodiments of the present application, the first pole piece connection portion is connected to one side of the first positive electrode current collector along the second direction and / or the third direction, the second pole piece connection portion is connected to one side of the first negative electrode current collector along the second direction and / or the third direction, and the first pole piece connection portion and the second pole piece connection portion are located on different sides of the electrode assembly. The first direction, the second direction and the third direction are perpendicular to each other.

[0021] In the above technical solution, by locating the first pole piece connection portion and the second pole piece connection portion on different sides of the electrode assembly, the risk of short circuit caused by contact between the first pole piece connection portion and the second pole piece connection portion can be reduced.

[0022] In some embodiments of the present application, a first pole lug and a second pole lug extend from one end of the battery cell along the third direction, and the first pole piece connecting portion or the second pole piece connecting portion is arranged between the first pole lug and the second pole lug.

[0023] In the above technical solution, a large space is reserved between the first pole lug and the second pole lug. By arranging the first pole piece connection portion or the second pole piece connection portion between the first pole lug and the second pole lug, the preparation of the first pole piece connection portion or the second pole piece connection portion can be facilitated, and the length of the first pole piece connection portion or the second pole piece connection portion can be larger, and the connection strength and the current-carrying capacity can be higher.

[0024] In some embodiments of the present application, the first electrode sheet group includes a plurality of first positive electrode sheets and a plurality of first negative electrode sheets, the second electrode sheet group includes a plurality of second positive electrode sheets and a plurality of second negative electrode sheets, each first positive electrode sheet is connected to a second positive electrode sheet via a first electrode sheet connection portion, and each first negative electrode sheet is connected to a second negative electrode sheet via a second electrode sheet connection portion. The plurality of first electrode sheet connection portions are located on the same side of the electrode assembly, and the plurality of second electrode sheet connection portions are located on the same side of the electrode assembly.

[0025] In the above technical solution, by making the first electrode sheet group include a plurality of first positive electrode sheets and a plurality of first negative electrode sheets, and the second electrode sheet group include a plurality of second positive electrode sheets and a plurality of second negative electrode sheets, the volume of the second electrode sheet group can be made larger, and the step space formed on at least one side of the second electrode sheet group is larger, which can accommodate more components in the battery compartment. By making the plurality of first electrode sheet connecting parts located on the same side of the electrode assembly and the plurality of second electrode sheet connecting parts located on the same side of the electrode assembly, it is possible to facilitate the arrangement of the plurality of first electrode sheet connecting parts and the plurality of second electrode sheet connecting parts, and the possibility of short circuit between the first electrode sheet group and the second electrode sheet group is low.

[0026] In some embodiments of the present application, the first pole piece group also includes a first end pole piece, which is a pole piece in the first pole piece group that is closest to the second pole piece group, and the first positive pole piece and the first negative pole piece are both located on the side of the first end pole piece that is away from the second pole piece group.

[0027] In the above technical solution, by making the first pole piece group also include a first end pole piece, the first end pole piece is a pole piece in the first pole piece group that is closest to the second pole piece group, and the first positive pole piece and the first negative pole piece are both located on the side of the first end pole piece away from the second pole piece group, it is convenient to connect the first positive pole piece with the second positive pole piece through the first pole piece connecting part, and to connect the first negative pole piece with the second negative pole piece through the second pole piece connecting part.

[0028] In some embodiments of the present application, a third diaphragm and a fourth diaphragm are respectively provided on both sides of the first end electrode piece in the thickness direction. The electrode assembly includes a second diaphragm connecting portion, the second diaphragm connecting portion connects the third diaphragm and the fourth diaphragm, and the third diaphragm, the second diaphragm connecting portion, and the fourth diaphragm are integrally formed. The second diaphragm connecting portion is located on a side of the first end electrode piece close to the second electrode piece connecting portion.

[0029] In the above technical solution, by respectively arranging the third diaphragm and the fourth diaphragm on both sides of the first end electrode sheet along the thickness direction, the first end electrode sheet can be isolated and insulated from other electrode sheets, thereby reducing the possibility of short circuit of the electrode assembly. By making the second diaphragm connecting portion connect the third diaphragm and the fourth diaphragm, and the third diaphragm, the second diaphragm connecting portion, and the fourth diaphragm are integrally formed, the relative position between the third diaphragm and the fourth diaphragm can be made more stable, reducing the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group, and the reliability of the battery cell is higher. By making the second diaphragm connecting portion located on the side of the first end electrode sheet close to the second electrode sheet connecting portion, after the first electrode sheet group and the second electrode sheet group are prepared and formed, the first electrode sheet connecting portion, the second electrode sheet connecting portion, and the second diaphragm connecting portion can be bent once so that the second electrode sheet group can be stacked on the first electrode sheet group, thereby facilitating the preparation of the electrode assembly.

[0030] In some embodiments of the present application, the first end electrode plate is a positive electrode plate, the third diaphragm is disposed between the first end electrode plate and the first negative electrode plate, and the fourth diaphragm is disposed between the first end electrode plate and the second negative electrode plate.

[0031] In the above technical solution, by making the first end electrode sheet a positive electrode sheet, the third diaphragm is arranged between the first end electrode sheet and the first negative electrode sheet, and the fourth diaphragm is arranged between the first end electrode sheet and the second negative electrode sheet, positive electrode active material layers can be arranged on both sides of the first end electrode sheet to correspond to the first negative electrode sheet and the second negative electrode sheet respectively, which is beneficial to increase the volume ratio of the active material layer in the electrode assembly, thereby helping to improve the energy density of the battery cell.

[0032] In some embodiments of the present application, the first pole piece connection portion is bent around the first end pole piece. The second pole piece connection portion is bent around the first end pole piece.

[0033] In the above technical solution, by making the first pole piece connection part bend around the first end pole piece, the bending angle of the first pole piece connection part can be made smaller, reducing the possibility of the first pole piece connection part cracking due to excessive bending angle, and the first pole piece connection part occupies a smaller area in the direction perpendicular to the thickness direction of the electrode assembly, which is beneficial to improving the energy density of the battery cell. By making the second pole piece connection part bend around the first end pole piece, the bending angle of the second pole piece connection part can be made smaller, reducing the possibility of the second pole piece connection part cracking due to excessive bending angle, and the second pole piece connection part occupies a smaller area in the direction perpendicular to the thickness direction of the electrode assembly, which is beneficial to improving the energy density of the battery cell.

[0034] In some embodiments of the present application, the electrode assembly further includes a first positive electrode tab and a first negative electrode tab. The first positive electrode tab is connected to one end of the first positive electrode sheet along the third direction, and the first positive electrode sheet and the second positive electrode sheet share the first positive electrode tab. The first negative electrode tab is connected to one end of the first negative electrode sheet along the third direction, and the first negative electrode sheet and the second negative electrode sheet share the second negative electrode tab. The first direction, the second direction and the third direction are perpendicular to each other.

[0035] In the above technical solution, by connecting the first positive electrode tab to one end of the first positive electrode sheet along the third direction, and connecting the first negative electrode tab to one end of the first negative electrode sheet along the third direction, the first positive electrode tab and the first negative electrode tab can be easily led out from one end of the electrode assembly along the third direction. By making the first positive electrode sheet and the second positive electrode sheet share the first positive electrode tab, and the first negative electrode sheet and the second negative electrode sheet share the second negative electrode tab, the positions of the first positive electrode tab and the first negative electrode tab in the second direction of the first electrode sheet group are not restricted, so that the battery cell can be applied to more types of electrical equipment.

[0036] In some embodiments of the present application, the first electrode group further includes a third positive electrode sheet and a third negative electrode sheet stacked along the first direction. Along the first direction, the third positive electrode sheet and the third negative electrode sheet are arranged on a side of the first positive electrode sheet and the first negative electrode sheet away from the second electrode group.

[0037] In the above technical solution, by making the first electrode sheet group further include a third positive electrode sheet and a third negative electrode sheet stacked along the first direction, the number of electrode sheets in the first electrode sheet group can be increased and the capacity of the battery cell can be increased. By making the third positive electrode sheet and the third negative electrode sheet arranged on the side of the first positive electrode sheet and the first negative electrode sheet away from the second electrode sheet group along the first direction, the first positive electrode sheet and the second negative electrode sheet can be closer to the second electrode sheet group, so as to facilitate the first positive electrode collector of the first positive electrode sheet to be connected to the second positive electrode collector through the first electrode sheet connecting portion, and facilitate the first negative electrode collector of the first negative electrode sheet to be connected to the second negative electrode collector through the second electrode sheet connecting portion.

[0038] In some embodiments of the present application, the electrode assembly further includes a second positive electrode tab and a second negative electrode tab. The second positive electrode tab is connected to one end of the third positive electrode sheet along the third direction, and along the first direction, the first positive electrode tab and the second positive electrode tab at least partially overlap and are connected. The second negative electrode tab is connected to one end of the third negative electrode sheet along the third direction, and along the first direction, the first negative electrode tab and the second negative electrode tab at least partially overlap and are connected. The battery cell further includes a package, a first electrical connector and a second electrical connector, and the electrode assembly is accommodated in the package, one end of the first electrical connector is connected to the first positive electrode tab and the second positive electrode tab, and the other end extends out of the package. One end of the second electrical connector is connected to the first negative electrode tab and the second negative electrode tab, and the other end extends out of the package.

[0039] In the above technical solution, by connecting the second positive electrode tab to one end of the third positive electrode sheet along the third direction, along the first direction, the first positive electrode tab and the second positive electrode tab at least partially overlap and are connected; the second negative electrode tab is connected to one end of the third negative electrode sheet along the third direction, along the first direction, the first negative electrode tab and the second negative electrode tab at least partially overlap and are connected, so that the first positive electrode sheet and the third positive electrode sheet are electrically connected through the first positive electrode tab and the second positive electrode tab, and the first negative electrode sheet and the third negative electrode sheet are electrically connected through the first negative electrode tab and the second negative electrode tab. By accommodating the electrode assembly in the packaging, the packaging can protect the electrode assembly. By connecting one end of the first electrical connector to the first positive electrode tab and the second positive electrode tab, and extending the other end out of the package; connecting one end of the second electrical connector to the first negative electrode tab and the second negative electrode tab, and extending the other end out of the package, the positive terminal and the negative terminal of the electrode assembly can be led out of the package through the first electrical connector and the second electrical connector respectively, so as to realize electrical connection between the battery cell and the load.

[0040] In some embodiments of the present application, along the first direction, the first electrode group includes a first portion overlapping with the second electrode group and a second portion not overlapping with the second electrode group. Along the third direction, the projection of the first positive electrode tab and / or the projection of the first negative electrode tab overlaps with the second portion.

[0041] In the above technical solution, in the solution of realizing electrical connection between the pole pieces of the step battery cell through the pole piece, in order to facilitate the pole piece of the first pole piece group and the pole piece of the second pole piece group to be folded and connected, the pole piece of the first pole piece group can only be set in the first part overlapping with the second pole piece group, resulting in the limitation of the setting position of the pole piece. In the present application, the first pole piece group and the second pole piece group are connected through the pole piece connecting part, so that the second pole piece group does not need to be provided with a pole piece, and the pole piece of the first pole piece group can be set at any position along the second direction, that is, the pole piece of the first pole piece group can be set in the second part that does not overlap with the second pole piece group, so that the battery cell can be applied to more types of electrical equipment.

[0042] In some embodiments of the present application, the battery cell further includes a packaging member, the packaging member includes a main body, the main body includes a first main body and a second main body, the first main body and the second main body are arranged side by side along the second direction, the second main body has a first outer surface in the first direction, and the first main body protrudes from the first outer surface. When viewed along the first direction, the first pole piece group includes a first portion overlapping with the second pole piece group and a second portion not overlapping with the second pole piece group, and the first portion and the second portion are arranged and connected along the second direction. The first portion and the second pole piece group are accommodated in the first main body, and the second portion is accommodated in the second main body.

[0043] In the above technical solution, the first main body is made to protrude from the first outer surface of the first main body; the first part of the first electrode group and the second electrode group are accommodated in the first main body, and the second part of the first electrode group is accommodated in the second main body, so that a step is formed in the package corresponding to the electrode assembly, so that the space utilization rate in the package is high, which is beneficial to improving the energy density of the battery cell, and it is convenient to arrange other components of the electrical equipment at the step of the package, which is beneficial to improving the space utilization rate of the battery compartment of the electrical equipment, and thus can improve the compactness of the internal structure of the electrical equipment.

[0044] In a second aspect, the present application provides an electrical device, including a battery cell as described above, and the battery cell is used to provide electrical energy.

[0045] In a third aspect, the present application provides a pole piece, comprising a first sub-pole piece, a second sub-pole piece and a pole piece connecting portion, wherein the size of the first sub-pole piece along the second direction is greater than the size of the second sub-pole piece along the second direction, the first sub-pole piece comprises a first current collector, the second sub-pole piece comprises a second current collector, and the pole piece connecting portion connects the first current collector and the second current collector.

[0046] In some embodiments of the present application, the pole piece connecting portion is integrally formed with the first current collector and the second current collector.

[0047] In the above technical solution, by integrally forming the pole piece connection portion with the first current collector and the second current collector, the preparation of the first current collector, the pole piece connection portion and the second current collector can be facilitated, and the connection strength between the first sub-pole piece and the second sub-pole piece is higher and the relative position is more stable.

[0048] In some embodiments of the present application, a first active material layer is disposed on the surface of the first current collector, a second active material layer is disposed on the surface of the second current collector, and the pole piece connecting portion is an empty foil area.

[0049] In the above technical solution, a first active material layer is provided on the surface of the first current collector, a second active material layer is provided on the surface of the second current collector, and the pole piece connecting portion is a hollow foil area, so that the pole piece connecting portion can realize electrical connection between the first sub-pole piece and the second sub-pole piece, and the thickness of the pole piece connecting portion is small, which is convenient for bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] 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.

[0051] Figure 1 A schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0052] Figure 2 A three-dimensional schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0053] Figure 3 A schematic structural diagram of a battery cell from one perspective provided in some embodiments of the present application;

[0054] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure of part of the battery cell along AA;

[0055] Figure 5 for Figure 4 A schematic diagram of the partial enlarged structure of the B part of the middle cell;

[0056] Figure 6 for Figure 4 A schematic diagram of the partial enlarged structure of the C part of the middle cell;

[0057] Figure 7 for Figure 4 A schematic diagram of the partial enlarged structure at D of the middle cell;

[0058] Figure 8 This is a schematic diagram of the structure of the first positive electrode sheet and the second positive electrode sheet of the battery cell after unfolding in some embodiments of the present application;

[0059] Fig. 9 for Figure 8 Schematic diagram of the cross-sectional structure of part of the battery cell along EE;

[0060] Fig.10 for Fig. 9 A schematic diagram of the partial enlarged structure of the F part of the middle cell;

[0061] Fig.11 This is a schematic diagram of the structure of the first negative electrode sheet and the second negative electrode sheet of the battery cell after unfolding in some embodiments of the present application;

[0062] Fig.12 This is a schematic diagram of the structure of the first diaphragm and the second diaphragm after unfolding in some embodiments of the present application;

[0063] Fig.13 Schematic diagram of the structure of the first positive electrode sheet and the second positive electrode sheet after unfolding in some other embodiments of the present application;

[0064] Fig.14 Schematic diagram of the structure of the first negative electrode sheet and the second negative electrode sheet after unfolding in some other embodiments of the present application;

[0065] Fig.15 A structural schematic diagram of a partial structure of a battery cell provided in some other embodiments of the present application from one perspective;

[0066] Fig.16 A structural schematic diagram of a partial structure of a battery cell provided in some other embodiments of the present application from one perspective;

[0067] Fig.17 A schematic diagram of the structure of the pole piece provided in some embodiments of the present application.

[0068] Icons: 10-battery cell; 100-electrode assembly; 110-first electrode group; 110a-first part; 110b-second part; 111-first positive electrode; 1111-first positive current collector; 1111a-first positive electrode ear; 1112-first positive active material layer; 112-first negative electrode; 1121-first negative current collector; 1121a-first negative electrode ear; 1122-first negative active material layer; 113-first diaphragm; 114-first end electrode; 115-third diaphragm; 116-fourth diaphragm; 117-third positive electrode; 118-third negative electrode; 120-second electrode group; 121-second positive electrode; 1211-second positive electrode Pole collector; 1212-second positive electrode active material layer; 122-second negative electrode plate; 1221-second negative electrode collector; 1222-second negative electrode active material layer; 123-second diaphragm; 131-first electrode plate connection portion; 132-second electrode plate connection portion; 133-first diaphragm connection portion; 134-second diaphragm connection portion; 200-packaging; 210-main body; 211-first main body; 212-second main body; 2121-first outer surface; 310-first electrical connector; 320-second electrical connector; pole piece-20; 201-first sub-pole piece; 202-second sub-pole piece; 203-pole piece connection portion; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] With the development of the new energy industry, batteries are gradually developing in the direction of high energy density and high power density. In order to adapt to different electrical equipment, batteries of different shapes need to be used, including square batteries, cylindrical batteries or special-shaped batteries. For example, special-shaped batteries with steps are composed of stacked pole pieces of various sizes, and generally multiple pole pieces are electrically connected through pole ears, so that the pole ears need to be set in the overlapping area of ​​multiple pole piece groups, so that the pole ears of multiple pole piece groups can be stacked and connected. However, due to the limitation of the position of the pole ears, the structure of the battery cell is also restricted, so that this type of battery cell can only be used for some types of electrical equipment.

[0075] In order to expand the application scope of a battery cell, the present application provides a battery cell, which includes an electrode assembly, the electrode assembly includes a first electrode sheet group and a second electrode sheet group stacked along a first direction, a first electrode sheet connection portion and a second electrode sheet connection portion, the size of the first electrode sheet group along the second direction is greater than the size of the second electrode sheet group along the second direction, and the first direction is perpendicular to the second direction. The first electrode sheet group includes a first positive electrode sheet and a first negative electrode sheet stacked along the first direction, the first positive electrode sheet includes a first positive electrode collector, and the first negative electrode sheet includes a first negative electrode collector. The second electrode sheet group includes a second positive electrode sheet and a second negative electrode sheet stacked along the first direction, the second positive electrode sheet includes a second positive electrode collector, and the second negative electrode sheet includes a second negative electrode collector. The first electrode sheet connection portion connects the first positive electrode collector and the second positive electrode collector. The second electrode sheet connection portion connects the first negative electrode collector and the second negative electrode collector.

[0076] In a battery cell of this structure, the first electrode plate group and the second electrode plate group are stacked along a first direction, the size of the first electrode plate group along the second direction is larger than the size of the second electrode plate group along the second direction, and the first direction is perpendicular to the second direction, so that a step is formed on at least one side of the electrode assembly along the second direction. When the battery cell is assembled in a battery compartment of an electrical device, other components in the battery compartment can be placed on the step, which is beneficial to improving the space utilization of the battery compartment, and further improving the compactness of the internal structure of the electrical device. By making the first electrode sheet connection portion connect the first positive electrode collector and the second positive electrode collector; the second electrode sheet connection portion connects the first negative electrode collector and the second negative electrode collector, the first positive electrode sheet of the first electrode sheet group and the second positive electrode sheet of the second electrode sheet group can be electrically connected through the first electrode sheet connection portion, and the first negative electrode sheet of the first electrode sheet group and the second negative electrode sheet of the second electrode sheet group can be electrically connected through the second electrode sheet connection portion, so that the positive and negative electrodes of the electrode assembly can be led out only through one of the first electrode sheet group and the second electrode sheet group, and the positive electrode tabs and negative electrode tabs in the electrode assembly can be set at any position, so that the application range of the battery cell is wider, and the relative positions between the first positive electrode sheet and the second positive electrode sheet, and between the first negative electrode sheet and the second negative electrode sheet can be made more stable, reducing the possibility of displacement of the second electrode sheet group relative to the first electrode sheet group, and the reliability of the battery cell is higher.

[0077] 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 battery cell can be cylindrical, flat, rectangular or other shapes, etc., which is not limited in the embodiment of the present application.

[0078] The embodiments of the present application provide an electrical device that uses a battery cell 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.

[0079] See also Figure 1 and Figure 2 , Figure 1 A schematic diagram of a 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.

[0080] The present application provides a battery cell 10, which includes an electrode assembly 100, wherein the electrode assembly 100 includes a first electrode plate group 110 and a second electrode plate group 120 stacked along a first direction X, wherein a size of the first electrode plate group 110 along a second direction Y is greater than a size of the second electrode plate group 120 along the second direction Y, and the first direction X is perpendicular to the second direction Y.

[0081] By stacking the first electrode plate group 110 and the second electrode plate group 120 along the first direction X, the size of the first electrode plate group 110 along the second direction Y is greater than the size of the second electrode plate group 120 along the second direction Y, and the first direction X is perpendicular to the second direction Y, so that a step is formed on at least one side of the electrode assembly 100 along the second direction Y, so that when the battery cell 10 is assembled in the battery compartment of an electrical device, other components in the battery compartment can be placed on the step, which is beneficial to improving the space utilization of the battery compartment, and further can improve the compactness of the internal structure of the electrical device.

[0082] See also Figures 3 to 11 , Figure 3 A schematic structural diagram of a battery cell from one perspective provided in some embodiments of the present application; Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure of part of the battery cell along AA; Figure 5 for Figure 4 A schematic diagram of the partial enlarged structure of the B part of the middle cell; Figure 6 for Figure 4 A schematic diagram of the partial enlarged structure of the C part of the middle cell; Figure 7 for Figure 4 A schematic diagram of the partial enlarged structure at D of the middle cell; Figure 8 This is a schematic diagram of the structure of the first positive electrode sheet and the second positive electrode sheet of the battery cell after unfolding in some embodiments of the present application; Fig. 9 for Figure 8 Schematic diagram of the cross-sectional structure of part of the battery cell along EE; Fig.10 for Fig. 9 A schematic diagram of the partial enlarged structure of the F part of the middle cell; Fig.11 This is a schematic diagram of the structure of the first negative electrode sheet and the second negative electrode sheet of the battery cell after they are unfolded in some embodiments of the present application.

[0083] In some embodiments, the battery cell 10 includes a first electrode sheet connection portion 131 and a second electrode sheet connection portion 132, the first electrode sheet group 110 includes a first positive electrode sheet 111 and a first negative electrode sheet 112 stacked along a first direction X, the first positive electrode sheet 111 includes a first positive electrode collector 1111, and the first negative electrode sheet 112 includes a first negative electrode collector 1112. The second electrode sheet group 120 includes a second positive electrode sheet 121 and a second negative electrode sheet 122 stacked along the first direction X, the second positive electrode sheet 121 includes a second positive electrode collector 1211, and the second negative electrode sheet 122 includes a second negative electrode collector 1221. The first electrode sheet connection portion 131 connects the first positive electrode collector 1111 and the second positive electrode collector 1211, and the first positive electrode collector 1111, the first electrode sheet connection portion 131, and the second positive electrode collector 1211 are integrally formed. The second electrode sheet connection portion 132 connects the first negative electrode current collector 1112 and the second negative electrode current collector 1221 , and the first negative electrode current collector 1112 , the second electrode sheet connection portion 132 , and the second negative electrode current collector 1221 are integrally formed.

[0084] By making the first electrode sheet connection portion 131 connect the first positive electrode current collector 1111 and the second positive electrode current collector 1211, and the first positive electrode current collector 1111, the first electrode sheet connection portion 131, and the second positive electrode current collector 1211 are integrally formed; the second electrode sheet connection portion 132 connects the first negative electrode current collector 1112 and the second negative electrode current collector 1221, and the first negative electrode current collector 1112, the second electrode sheet connection portion 132, and the second negative electrode current collector 1221 are integrally formed, so that the first positive electrode sheet 111 of the first electrode sheet group 110 and the second positive electrode sheet 121 of the second electrode sheet group 120 can be electrically connected through the first electrode sheet connection portion 131, and the first negative electrode current collector 1112, the second electrode sheet connection portion 132, and the second negative electrode current collector 1221 are integrally formed. The positive electrode sheet 112 and the second negative electrode sheet 122 of the second electrode sheet group 120 can be electrically connected through the second electrode sheet connecting portion 132, so that the positive and negative electrodes of the electrode assembly 100 can be led out only through one of the first electrode sheet group 110 and the second electrode sheet group 120. The positive electrode tabs and the negative electrode tabs in the electrode assembly 100 can be set at any position, so that the application range of the battery cell 10 is wider, and the relative positions between the first positive electrode sheet 111 and the second positive electrode sheet 121, and between the first negative electrode sheet 112 and the second negative electrode sheet 122 can be made more stable, thereby reducing the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110, and the reliability of the battery cell 10 is higher.

[0085] By integrally forming the first positive current collector 1111, the first electrode sheet connection portion 131, and the second positive current collector 1211, the preparation of the first positive current collector 1111, the first electrode sheet connection portion 131, and the second positive current collector 1211 can be facilitated, and the connection strength between the first positive electrode sheet 111 and the second positive electrode sheet 121 is higher, and the relative position is more stable.

[0086] By integrally forming the first negative electrode current collector 1112, the second electrode sheet connection portion 132, and the second negative electrode current collector 1221, the preparation of the first negative electrode current collector 1112, the second electrode sheet connection portion 132, and the second negative electrode current collector 1221 can be facilitated, and the connection strength between the first negative electrode sheet 112 and the second negative electrode sheet 122 is higher, and the relative position is more stable.

[0087] In some embodiments, the first positive electrode plate 111 further includes a first positive active material layer 1112, which is disposed on both sides of the first positive current collector 1111 along the first direction X. The first negative electrode plate 112 further includes a first negative active material layer 1122, which is disposed on both sides of the first negative current collector 1121 along the first direction X. The second positive electrode plate 121 further includes a second positive active material layer 1212, which is disposed on both sides of the second positive current collector 1211 along the first direction X. The second negative electrode plate 122 further includes a second negative active material layer 1222, which is disposed on both sides of the second negative current collector 1221 along the first direction X.

[0088] The battery cell 10 mainly relies on the movement of metal ions between the positive electrode plate and the negative electrode plate to work. The positive electrode plate includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector. Taking a lithium-ion battery 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, etc. The negative electrode plate includes a negative electrode collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode collector. The material of the negative electrode collector can be copper, and the negative electrode active material can be a carbon material or a silicon material, etc.

[0089] In some embodiments, the electrode assembly 100 is a laminated structure formed by stacking a negative electrode sheet, a separator, and a positive electrode sheet.

[0090] In some embodiments, the battery cell 10 is in the shape of a rectangular parallelepiped with rounded top corners, so as to better fit into a rounded battery compartment in an electrical device.

[0091] In other embodiments, the top corners of the battery cell 10 may also be arranged in a square angle.

[0092] See also Figure 5 and Fig.12 , Fig.12 This is a schematic diagram of the structure of the first diaphragm and the second diaphragm after unfolding in some embodiments of the present application.

[0093] In some embodiments, a first diaphragm 113 is disposed between the first negative electrode sheet 112 and the first positive electrode sheet 111, and a second diaphragm 123 is disposed between the second negative electrode sheet 122 and the second positive electrode sheet 121. The electrode assembly 100 includes a first diaphragm connecting portion 133, the first diaphragm connecting portion 133 connects the first diaphragm 113 and the second diaphragm 123, and the first diaphragm 113, the first diaphragm connecting portion 133, and the second diaphragm 123 are integrally formed. The first diaphragm connecting portion 133 is disposed between the first electrode sheet connecting portion 131 and the second electrode sheet connecting portion 132.

[0094] A first diaphragm 113 is provided between the first negative electrode sheet 112 and the first positive electrode sheet 111, so that the first diaphragm 113 plays a role of isolating and insulating the first negative electrode sheet 112 and the first positive electrode sheet 111. A second diaphragm 123 is provided between the second negative electrode sheet 122 and the second positive electrode sheet 121, so that the second diaphragm 123 plays a role of isolating and insulating the second negative electrode sheet 122 and the second positive electrode sheet 121. By connecting the first diaphragm connecting portion 133 to the first diaphragm 113 and the second diaphragm 123, and the first diaphragm 113, the first diaphragm connecting portion 133, and the second diaphragm 123 are integrally formed, the relative position between the first diaphragm 113 and the second diaphragm 123 can be made more stable, the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 is reduced, and the reliability of the battery cell 10 is higher. The first diaphragm connecting portion 133 is arranged between the first pole piece connecting portion 131 and the second pole piece connecting portion 132, so that the first diaphragm connecting portion 133 plays an isolating and insulating role between the first pole piece connecting portion 131 and the second pole piece connecting portion 132, and after the first pole piece group 110 and the second pole piece group 120 are prepared and formed, the first pole piece connecting portion 131, the second pole piece connecting portion 132, and the first diaphragm connecting portion 133 can be bent once so that the second pole piece group 120 can be stacked on the first pole piece group 110, which is convenient for the preparation of the electrode assembly 100.

[0095] In some embodiments, the material of the diaphragm may be polypropylene (PP) or polyethylene (PE).

[0096] See also Figure 3 , Figure 8 and Fig.11In some embodiments, the first electrode connecting portion 131 connects one side of the first positive electrode current collector 1111 along the second direction Y and one side of the second positive electrode current collector 1211 along the second direction Y. The second electrode connecting portion 132 connects one side of the first negative electrode current collector 1112 along the second direction Y and one side of the second negative electrode current collector 1221 along the second direction Y.

[0097] By connecting the first electrode sheet connection portion 131 to one side of the first positive electrode current collector 1111 along the second direction Y and the second positive electrode current collector 1211 along the second direction Y, and connecting the second electrode sheet connection portion 132 to one side of the first negative electrode current collector 1112 along the second direction Y and the second negative electrode current collector 1221 along the second direction Y, after the first electrode sheet group 110 and the second electrode sheet group 120 are prepared and formed, the first electrode sheet connection portion 131 and the second electrode sheet connection portion 132 can be bent once so that the second electrode sheet group 120 can be stacked on the first electrode sheet group 110, which is convenient for the preparation of the electrode assembly 100.

[0098] In some embodiments, the first direction X is parallel to the thickness direction of the battery cell 10, the second direction Y is parallel to the width direction of the battery cell 10, and the third direction Z is parallel to the length direction of the battery cell 10. By making the first electrode sheet connection portion 131 connect one side of the first positive electrode current collector 1111 along the second direction Y and one side of the second positive electrode current collector 1211 along the second direction Y; the second electrode sheet connection portion 132 connects one side of the first negative electrode current collector 1112 along the second direction Y and one side of the second negative electrode current collector 1221 along the second direction Y, the first electrode sheet connection portion 131 and the second electrode sheet connection portion 132 can be set longer, thereby making the connection strength between the first positive electrode current collector 1111 and the second positive electrode current collector 1211, and the first negative electrode current collector 1112 and the second negative electrode current collector 1221 higher, further reducing the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110, and the reliability of the battery cell 10 is higher.

[0099] See also Fig.12 In some embodiments, along the third direction Z, the length of the first diaphragm connecting portion 133 is greater than or equal to the length of the first pole piece connecting portion 131. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0100] By making the length of the first diaphragm connection part 133 greater than or equal to the length of the first pole piece connection part 131 along the third direction Z, the first diaphragm connection part 133 can further provide better isolation and insulation effect between the first pole piece connection part 131 and the second pole piece connection part 132, thereby reducing the possibility of short circuit of the electrode assembly 100 and improving the safety of the battery cell 10.

[0101] In some embodiments, along the third direction Z, the length of the first diaphragm connecting portion 133 is greater than or equal to the length of the second pole piece connecting portion 132 .

[0102] By making the length of the first diaphragm connection part 133 greater than or equal to the length of the second pole piece connection part 132 along the third direction Z, the first diaphragm connection part 133 can further provide better isolation and insulation effect between the first pole piece connection part 131 and the second pole piece connection part 132, thereby reducing the possibility of short circuit of the electrode assembly 100 and improving the safety of the battery cell 10.

[0103] See also Figure 8 In some embodiments, along the third direction Z, the length of the first electrode connecting portion 131 is L1, and the length of the first positive electrode plate 111 is L2, satisfying 0.1≤L1 / L2≤1. For example, L1 / L2 can be 0.1, 0.3, 0.5, 0.8 or 1.

[0104] The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0105] When L1 / L2 is greater than or equal to 0.1, the length of the first electrode sheet connection portion 131 can be larger, so that the connection strength between the first positive current collector 1111 and the second positive current collector 1211 is higher, and the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 is further reduced, and the reliability of the battery cell 10 is higher; when L1 / L2 is less than or equal to 1, L1 / L3 is less than or equal to 1, which can facilitate the preparation of the first electrode sheet connection portion 131; therefore, when 0.1≤L1 / L2≤1, the connection strength between the first positive current collector 1111 and the second positive current collector 1211 can be higher, and the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 can be further reduced, and the reliability of the battery cell 10 is higher, and the preparation of the first electrode sheet connection portion 131 can be facilitated.

[0106] In some embodiments, along the third direction Z, the length of the first electrode connecting portion 131 is L1, the length of the second positive electrode plate 121 is L3, and 0.1≤L1 / L3≤1. For example, L1 / L3 can be 0.1, 0.3, 0.5, 0.8 or 1.

[0107] When L1 / L3 is greater than or equal to 0.1, the length of the first electrode sheet connection portion 131 can be larger, so that the connection strength between the first positive current collector 1111 and the second positive current collector 1211 is higher, and the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 is further reduced, and the reliability of the battery cell 10 is higher; when L1 / L2 is less than or equal to 1, L1 / L3 is less than or equal to 1, which can facilitate the preparation of the first electrode sheet connection portion 131; therefore, when 0.1≤L1 / L3≤1, the connection strength between the first positive current collector 1111 and the second positive current collector 1211 can be higher, and the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 can be further reduced, and the reliability of the battery cell 10 is higher, and the preparation of the first electrode sheet connection portion 131 can be facilitated.

[0108] See also Figure 3 , Fig.13 and Fig.14 , Fig.13 Schematic diagram of the structure of the first positive electrode sheet and the second positive electrode sheet after unfolding in some other embodiments of the present application; Fig.14 This is a schematic diagram of the structure of the first negative electrode sheet and the second negative electrode sheet after unfolding in some other embodiments of the present application.

[0109] In some embodiments, the first electrode sheet connection portion 131 connects one side of the first positive electrode current collector 1111 along the third direction Z and one side of the second positive electrode current collector 1211 along the third direction Z. The second electrode sheet connection portion 132 connects one side of the first negative electrode current collector 1112 along the third direction Z and one side of the second negative electrode current collector 1221 along the third direction Z. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0110] By connecting the first electrode sheet connection portion 131 to one side of the first positive electrode current collector 1111 along the third direction Z and the second positive electrode current collector 1211 along the third direction Z, and connecting the second electrode sheet connection portion 132 to one side of the first negative electrode current collector 1112 along the third direction Z and the second negative electrode current collector 1221 along the third direction Z, after the first electrode sheet group 110 and the second electrode sheet group 120 are prepared and formed, the first electrode sheet connection portion 131 and the second electrode sheet connection portion 132 can be bent once so that the second electrode sheet group 120 can be stacked on the first electrode sheet group 110, which is convenient for the preparation of the electrode assembly 100.

[0111] In some embodiments, along the second direction Y, the length of the first diaphragm connecting portion 133 is greater than or equal to the length of the first pole piece connecting portion 131 .

[0112] By making the length of the first diaphragm connection part 133 greater than or equal to the length of the first pole piece connection part 131 along the second direction Y, the isolation and insulation effect between the first diaphragm connection part 133, the first pole piece connection part 131 and the second pole piece connection part 132 can be further improved, thereby reducing the possibility of short circuit of the electrode assembly 100 and improving the safety of the battery cell 10.

[0113] In some embodiments, the length of the first diaphragm connecting portion 133 is greater than or equal to the length of the second pole piece connecting portion 132 .

[0114] By making the length of the first diaphragm connection part 133 greater than or equal to the length of the second electrode piece connection part 132 along the second direction Y, the isolation and insulation effect between the first diaphragm connection part 133, the first electrode piece connection part 131 and the second electrode piece connection part 132 can be further improved, thereby reducing the possibility of short circuit of the electrode assembly 100 and improving the safety of the battery cell 10.

[0115] See also Fig.13 In some embodiments, along the second direction Y, the width of the first electrode connecting portion 131 is W1, and the width of the first positive electrode plate 111 is W2, satisfying 0.1≤W1 / W2≤1. For example, W1 / W2 can be 0.1, 0.3, 0.5, 0.8 or 1.

[0116] When W1 / W2 is greater than or equal to 0.1, the width of the first electrode sheet connection portion 131 can be larger, so that the connection strength between the first positive current collector 1111 and the second positive current collector 1211 is higher, and the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 is further reduced, and the reliability of the battery cell 10 is higher; when W1 / W2 is less than or equal to 1, it is convenient to prepare the first electrode sheet connection portion 131; therefore, when 0.1≤W1 / W2≤1, it is possible to make the connection strength between the first positive current collector 1111 and the second positive current collector 1211 higher, further reduce the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110, the reliability of the battery cell 10 is higher, and it is convenient to prepare the first electrode sheet connection portion 131.

[0117] In some embodiments, along the second direction Y, the width of the first electrode connecting portion 131 is W1, the width of the second positive electrode plate 121 is W3, and 0.1≤W1 / W3≤1. For example, W1 / W3 can be 0.1, 0.3, 0.5, 0.8 or 1.

[0118] When W1 / W3 is greater than or equal to 0.1, the width of the first electrode sheet connection portion 131 can be larger, so that the connection strength between the first positive current collector 1111 and the second positive current collector 1211 is higher, and the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110 is further reduced, and the reliability of the battery cell 10 is higher; when W1 / W3 is less than or equal to 1, it is convenient to prepare the first electrode sheet connection portion 131; therefore, when 0.1≤W1 / W3≤1, it is possible to make the connection strength between the first positive current collector 1111 and the second positive current collector 1211 higher, further reduce the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110, the reliability of the battery cell 10 is higher, and it is convenient to prepare the first electrode sheet connection portion 131.

[0119] In other embodiments, the first pole piece connection portion 131 is connected to one side of the first positive electrode current collector 1111 along the second direction Y / or the third direction Z, the second pole piece connection portion 132 is connected to one side of the first negative electrode current collector 1112 along the second direction Y / or the third direction Z, and the first pole piece connection portion 131 and the second pole piece connection portion 132 are located on different sides of the electrode assembly 100. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0120] By locating the first pole piece connection portion 131 and the second pole piece connection portion 132 on different sides of the electrode assembly 100 , the risk of short circuit between the first pole piece connection portion 131 and the second pole piece connection portion 132 can be reduced.

[0121] For example, the first pole piece connection portion 131 and the second pole piece connection portion 132 may be respectively located on both sides of the electrode assembly 100 along the second direction Y. For another example, the first pole piece connection portion 131 and the second pole piece connection portion 132 may be respectively located on both sides of the electrode assembly 100 along the third direction Z. For another example, the first pole piece connection portion 131 is located on one side of the electrode assembly 100 along the second direction Y, and the second pole piece connection portion 132 is located on one side of the electrode assembly 100 along the third direction Z.

[0122] In some embodiments, a first pole lug and a second pole lug extend from one end of the battery cell 10 along the third direction Z, and the first pole piece connecting portion 131 or the second pole piece connecting portion 132 is disposed between the first pole lug and the second pole lug.

[0123] A large space is reserved between the first pole ear and the second pole ear. By setting the first pole piece connection part 131 or the second pole piece connection part 132 between the first pole ear and the second pole ear, the preparation of the first pole piece connection part 131 or the second pole piece connection part 132 can be facilitated, and the length of the first pole piece connection part 131 or the second pole piece connection part 132 can be larger, and the connection strength and the current-carrying capacity can be higher.

[0124] In some embodiments, the first electrode sheet group 110 includes a plurality of first positive electrode sheets 111 and a plurality of first negative electrode sheets 112, and the second electrode sheet group 120 includes a plurality of second positive electrode sheets 121 and a plurality of second negative electrode sheets 122, each first positive electrode sheet 111 is connected to a second positive electrode sheet 121 via a first electrode sheet connection portion 131, and each first negative electrode sheet 112 is connected to a second negative electrode sheet 122 via a second electrode sheet connection portion 132. The plurality of first electrode sheet connection portions 131 are located on the same side of the electrode assembly 100, and the plurality of second electrode sheet connection portions 132 are located on the same side of the electrode assembly 100.

[0125] By making the first electrode sheet group 110 include a plurality of first positive electrode sheets 111 and a plurality of first negative electrode sheets 112, and the second electrode sheet group 120 include a plurality of second positive electrode sheets 121 and a plurality of second negative electrode sheets 122, the volume of the second electrode sheet group 120 can be made larger, and the step space formed on at least one side of the second electrode sheet group 120 is larger, which can accommodate more components in the battery compartment. By making the plurality of first electrode sheet connecting portions 131 and the plurality of second electrode sheet connecting portions 132 located on the same side of the electrode assembly 100, it is convenient to arrange the plurality of first electrode sheet connecting portions 131 and the plurality of second electrode sheet connecting portions 132, and the possibility of short circuit caused by contact between the first electrode sheet group 110 and the second electrode sheet group 120 is low.

[0126] See also Figures 4 to 7 In some embodiments, the first pole piece group 110 further includes a first end pole piece 114, which is a pole piece in the first pole piece group 110 that is closest to the second pole piece group 120, and the first positive pole piece 111 and the first negative pole piece 112 are both located on the side of the first end pole piece 114 that is away from the second pole piece group 120.

[0127] By making the first pole piece group 110 also include a first end pole piece 114, the first end pole piece 114 is the pole piece in the first pole piece group 110 that is closest to the second pole piece group 120, and the first positive pole piece 111 and the first negative pole piece 112 are both located on the side of the first end pole piece 114 that is away from the second pole piece group 120, it is convenient to connect the first positive pole piece 111 with the second positive pole piece 121 through the first pole piece connecting portion 131, and to connect the first negative pole piece 112 with the second negative pole piece 122 through the second pole piece connecting portion 132.

[0128] In some embodiments, the third diaphragm 115 and the fourth diaphragm 116 are respectively provided on both sides of the first end electrode piece 114 in the thickness direction. The electrode assembly 100 includes a second diaphragm connecting portion 134, which connects the third diaphragm 115 and the fourth diaphragm 116, and the third diaphragm 115, the second diaphragm connecting portion 134, and the fourth diaphragm 116 are integrally formed. The second diaphragm connecting portion 134 is located on one side of the first end electrode piece 114 close to the second electrode piece connecting portion 132.

[0129] By respectively arranging the third diaphragm 115 and the fourth diaphragm 116 on both sides of the first end electrode sheet 114 in the thickness direction, the first end electrode sheet 114 can be isolated and insulated from other electrode sheets, thereby reducing the possibility of short circuit of the electrode assembly 100. By making the second diaphragm connecting portion 134 connect the third diaphragm 115 and the fourth diaphragm 116, and the third diaphragm 115, the second diaphragm connecting portion 134, and the fourth diaphragm 116 are integrally formed, the relative position between the third diaphragm 115 and the fourth diaphragm 116 can be made more stable, reducing the possibility of displacement of the second electrode sheet group 120 relative to the first electrode sheet group 110, and the reliability of the battery cell 10 is higher. By locating the second diaphragm connection portion 134 on the side of the first end pole piece 114 close to the second pole piece connection portion 132, after the first pole piece group 110 and the second pole piece group 120 are prepared and formed, the first pole piece connection portion 131, the second pole piece connection portion 132 and the second diaphragm connection portion 134 can be bent once so that the second pole piece group 120 can be stacked on the first pole piece group 110, thereby facilitating the preparation of the electrode assembly 100.

[0130] In some embodiments, the first end electrode sheet 114 is a positive electrode sheet, the third diaphragm 115 is disposed between the first end electrode sheet 114 and the first negative electrode sheet 112 , and the fourth diaphragm 116 is disposed between the first end electrode sheet 114 and the second negative electrode sheet 122 .

[0131] By making the first end electrode sheet 114 a positive electrode sheet, the third diaphragm 115 is arranged between the first end electrode sheet 114 and the first negative electrode sheet 112, and the fourth diaphragm 116 is arranged between the first end electrode sheet 114 and the second negative electrode sheet 122, positive electrode active material layers can be arranged on both sides of the first end electrode sheet 114 to correspond to the first negative electrode sheet 112 and the second negative electrode sheet 122 respectively, which is beneficial to increase the volume ratio of the active material layer in the electrode assembly 100, thereby facilitating improving the energy density of the battery cell 10.

[0132] In other embodiments, the first end electrode plate 114 is a negative electrode plate, the third diaphragm 115 is disposed between the first end electrode plate 114 and the first positive electrode plate 111 , and the fourth diaphragm 116 is disposed between the first end electrode plate 114 and the second positive electrode plate 121 .

[0133] By making the first end electrode sheet 114 a negative electrode sheet, the third diaphragm 115 is arranged between the first end electrode sheet 114 and the first positive electrode sheet 111, and the fourth diaphragm 116 is arranged between the first end electrode sheet 114 and the second positive electrode sheet 121, negative electrode active material layers can be arranged on both sides of the first end electrode sheet 114 to correspond to the first positive electrode sheet 111 and the second positive electrode sheet 121 respectively, which is beneficial to increase the volume ratio of the active material layer in the electrode assembly 100, thereby facilitating improving the energy density of the battery cell 10.

[0134] In some embodiments, the first pole piece connecting portion 131 is bent around the first end pole piece 114 .

[0135] By bending the first pole piece connection portion 131 around the first end pole piece 114, the bending angle of the first pole piece connection portion 131 can be made smaller, thereby reducing the possibility of cracking of the first pole piece connection portion 131 due to excessive bending angle. In addition, the first pole piece connection portion 131 occupies a smaller area in the direction perpendicular to the thickness direction of the electrode assembly 100, which is beneficial to improving the energy density of the battery cell 10.

[0136] In some embodiments, the second pole piece connecting portion 132 is bent around the first end pole piece 114 .

[0137] By bending the second pole piece connection portion 132 around the first end pole piece 114, the bending angle of the second pole piece connection portion 132 can be made smaller, thereby reducing the possibility of cracking of the second pole piece connection portion 132 due to excessive bending angle. In addition, the area occupied by the second pole piece connection portion 132 in the direction perpendicular to the thickness direction of the electrode assembly 100 is smaller, which is beneficial to improving the energy density of the battery cell 10.

[0138] See also Figure 3 , Figure 8 and Fig.11 In some embodiments, the electrode assembly 100 further includes a first positive electrode tab 1111a and a first negative electrode tab 1211a. The first positive electrode tab 1111a is connected to one end of the first positive electrode sheet 111 along the third direction Z, and the first positive electrode sheet 111 and the second positive electrode sheet 121 share the first positive electrode tab 1111a. The first negative electrode tab 1211a is connected to one end of the first negative electrode sheet 112 along the third direction Z, and the first negative electrode sheet 112 and the second negative electrode sheet 122 share the second negative electrode tab. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0139] By connecting the first positive electrode tab 1111a to one end of the first positive electrode sheet 111 along the third direction Z, and connecting the first negative electrode tab 1211a to one end of the first negative electrode sheet 112 along the third direction Z, the first positive electrode tab 1111a and the first negative electrode tab 1211a can be easily led out from one end of the electrode assembly 100 along the third direction Z. By making the first positive electrode sheet 111 and the second positive electrode sheet 121 share the first positive electrode tab 1111a, and the first negative electrode sheet 112 and the second negative electrode sheet 122 share the second negative electrode tab, the positions of the first positive electrode tab 1111a and the first negative electrode tab 1211a in the second direction Y of the first electrode sheet assembly 110 are not restricted, so that the battery cell 10 can be applied to more types of electrical equipment.

[0140] In some embodiments, the portion of the positive electrode current collector not coated with the positive electrode active material layer can be used as a positive electrode tab to achieve power input or output of the positive electrode sheet through the positive electrode tab. The portion of the negative electrode current collector not coated with the negative electrode active material layer can be used as a negative electrode tab to achieve power input or output of the negative electrode sheet through the negative electrode tab.

[0141] See also Figures 4 to 7 In some embodiments, the first electrode sheet group 110 further includes a third positive electrode sheet 117 and a third negative electrode sheet 118 stacked along the first direction X. Along the first direction X, the third positive electrode sheet 117 and the third negative electrode sheet 118 are arranged on a side of the first positive electrode sheet 111 and the first negative electrode sheet 112 away from the second electrode sheet group 120.

[0142] By making the first electrode sheet group 110 further include the third positive electrode sheet 117 and the third negative electrode sheet 118 stacked along the first direction X, the number of electrode sheets in the first electrode sheet group 110 can be increased, and the capacity of the battery cell 10 can be increased. By making the third positive electrode sheet 117 and the third negative electrode sheet 118 arranged on the side of the first positive electrode sheet 111 and the first negative electrode sheet 112 away from the second electrode sheet group 120 along the first direction X, the first positive electrode sheet 111 and the second negative electrode sheet 122 can be closer to the second electrode sheet group 120, so as to facilitate the connection of the first positive current collector 1111 of the first positive electrode sheet 111 with the second positive current collector 1211 through the first electrode sheet connecting portion 131, and facilitate the connection of the first negative current collector 1112 of the first negative electrode sheet 112 with the second negative current collector 1221 through the second electrode sheet connecting portion 132.

[0143] In some embodiments, the electrode assembly 100 further includes a second positive electrode tab (not shown in the figure) and a second negative electrode tab (not shown in the figure). The second positive electrode tab is connected to one end of the third positive electrode sheet 117 along the third direction Z, and along the first direction X, the first positive electrode tab 1111a and the second positive electrode tab at least partially overlap and are connected. The second negative electrode tab is connected to one end of the third negative electrode sheet 118 along the third direction Z, and along the first direction X, the first negative electrode tab 1211a and the second negative electrode tab at least partially overlap and are connected. The battery cell 10 further includes a package 200, a first electrical connector 310 and a second electrical connector 320, and the electrode assembly 100 is accommodated in the package 200, one end of the first electrical connector 310 is connected to the first positive electrode tab 1111a and the second positive electrode tab, and the other end extends out of the package 200. One end of the second electrical connector 320 is connected to the first negative electrode tab 1211a and the second negative electrode tab, and the other end extends out of the package 200.

[0144] By connecting the second positive electrode tab to one end of the third positive electrode sheet 117 along the third direction Z, the first positive electrode tab 1111a and the second positive electrode tab at least partially overlap and connect along the first direction X; the second negative electrode tab is connected to one end of the third negative electrode sheet 118 along the third direction Z, and the first negative electrode tab 1211a and the second negative electrode tab at least partially overlap and connect along the first direction X, so that the first positive electrode sheet 111 and the third positive electrode sheet 117 are electrically connected through the first positive electrode tab 1111a and the second positive electrode tab, and the first negative electrode sheet 112 and the third negative electrode sheet 118 are electrically connected through the first negative electrode tab 1211a and the second negative electrode tab. By accommodating the electrode assembly 100 in the package 200, the package 200 can protect the electrode assembly 100. By connecting one end of the first electrical connector 310 to the first positive electrode tab 1111a and the second positive electrode tab, and extending the other end out of the package 200; connecting one end of the second electrical connector 320 to the first negative electrode tab 1211a and the second negative electrode tab, and extending the other end out of the package 200, the positive terminal and the negative terminal of the electrode assembly 100 can be led out of the package 200 through the first electrical connector 310 and the second electrical connector 320 respectively, so as to realize the electrical connection between the battery cell 10 and the load.

[0145] In some embodiments, the first electrical connector 310 and the first positive electrode tab 1111a and the second positive electrode tab may be welded, and the second electrical connector 320 and the first negative electrode tab 1211a and the second negative electrode tab may be welded.

[0146] In other embodiments, the first electrical connector 310 and the first positive electrode tab 1111a and the second positive electrode tab may be integrally formed, and the second electrical connector 320 and the first negative electrode tab 1211a and the second negative electrode tab may be integrally formed.

[0147] In some embodiments, the first electrical connector 310 and the second electrical connector 320 may be made of a material with good electrical conductivity, such as a metal material such as lead or copper.

[0148] See also Figure 3 , Fig.15 and Fig.16 , Fig.15 A structural schematic diagram of a partial structure of a battery cell provided in some other embodiments of the present application from one perspective; Fig.16 A structural schematic diagram of a partial structure of a battery cell provided in some other embodiments of the present application from one perspective.

[0149] In some embodiments, along the first direction X, the first electrode set 110 includes a first portion 110a overlapping with the second electrode set 120 and a second portion 110b not overlapping with the second electrode set 120. Along the third direction Z, the projection of the first positive electrode tab 1111a and / or the projection of the first negative electrode tab 1121a overlaps with the second portion 110b.

[0150] In the scheme of realizing electrical connection between the pole pieces of the step cell through the pole piece, in order to facilitate the pole piece of the first pole piece group 110 to be connected with the pole piece of the second pole piece group 120, the pole piece of the first pole piece group 110 can only be set in the first part 110a (such as Fig.15 In the present application, the first pole piece group 110 and the second pole piece group 120 are connected by a pole piece connecting portion, so that the second pole piece group 120 does not need to be provided with a pole piece, and the pole piece of the first pole piece group 110 can be set at any position along the second direction Y, that is, the pole piece of the first pole piece group 110 can be set at the second part 110b that does not overlap with the second pole piece group 120. Figure 3 and Fig.16 As shown), the battery cell 10 can be applied to more types of electrical equipment.

[0151] See also Figure 1In some embodiments, the battery cell 10 further includes a packaging member 200, the packaging member 200 includes a main body 210, the main body 210 includes a first main body 211 and a second main body 212, the first main body 211 and the second main body 212 are arranged side by side along the second direction Y, the second main body 212 has a first outer surface 2121 in the first direction X, and the first main body 211 protrudes from the first outer surface 2121. Observed along the first direction X, the first electrode assembly 110 includes a first portion 110a overlapping with the second electrode assembly 120 and a second portion 110b not overlapping with the second electrode assembly 120, the first portion 110a and the second portion 110b are arranged and connected along the second direction Y. The first portion 110a and the second electrode assembly 120 are accommodated in the first main body 211, and the second portion 110b is accommodated in the second main body 212.

[0152] By making the first main body 211 protrude from the first outer surface 2121 of the first main body 211; the first part 110a of the first electrode plate group 110 and the second electrode plate group 120 are accommodated in the first main body 211, and the second part 110b of the first electrode plate group 110 is accommodated in the second main body 212, so that the package 200 forms a step corresponding to the electrode assembly 100, so that the space utilization rate in the package 200 is high, which is beneficial to improving the energy density of the battery cell 10, and it is convenient to arrange other components of the electrical equipment at the step of the package 200, which is beneficial to improving the space utilization rate of the battery compartment of the electrical equipment, and thus can improve the compactness of the internal structure of the electrical equipment.

[0153] In some embodiments, the packaging member 200 may be a packaging bag, and the packaging bag may be an aluminum-plastic film, a steel-plastic film, or the like.

[0154] In other embodiments, the package 200 may be a shell, which may be made of a material with relatively high strength, such as metal materials such as steel and aluminum alloy, or non-metallic materials such as carbon fiber and hard plastic, so that the package 200 has relatively high force-bearing performance, thereby making it less likely for the package 200 to be deformed or damaged due to force or environmental changes, thereby making the battery cell 10 more reliable.

[0155] In some embodiments, the battery cell 10 further includes an electrolyte, which is contained in the package 200. Metal ions move between the positive electrode sheet and the negative electrode sheet through the electrolyte.

[0156] In some embodiments, the electrolyte may include an organic solvent, an electrolyte lithium salt, and the like.

[0157] See also Figure 2 and Figure 3In some embodiments, along the third direction Z, the projection of the first electrical connector 310 is located at the first portion 110a where the first pole piece group 110 overlaps with the second pole piece group 120, and the projection of the second electrical connector 320 is located at the second portion 110b where the first pole piece group 110 does not overlap with the second pole piece group 120.

[0158] See also Fig.15 ,

[0159] In some embodiments, along the third direction Z, the projections of the first electrical connector 310 and the second electrical connector 320 are located at the first portion 110 a where the first electrode set 110 and the second electrode set 120 overlap.

[0160] See also Fig.16 ,

[0161] In some embodiments, along the third direction Z, the projections of the first electrical connector 310 and the second electrical connector 320 are located at the second portion 110 b where the first electrode set 110 and the second electrode set 120 do not overlap.

[0162] In other embodiments, the positions of the first electrical connector 310 and the second electrical connector 320 may be set as required.

[0163] See also Fig.17 , Fig.17 A schematic diagram of the structure of the pole piece provided in some embodiments of the present application.

[0164] 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.

[0165] The electrical device may be any of the aforementioned devices or systems using the battery cell 10 .

[0166] The embodiment of the present application provides a pole piece 20, including a first sub-pole piece 201, a second sub-pole piece 202 and a pole piece connecting portion 203. The size of the first sub-pole piece 201 along the second direction Y is greater than the size of the second sub-pole piece 202 along the second direction Y. The first sub-pole piece 201 includes a first current collector (not shown in the figure), the second sub-pole piece 202 includes a second current collector (not shown in the figure), and the pole piece connecting portion 203 connects the first current collector and the second current collector.

[0167] In some embodiments, the pole piece connection portion 203 is integrally formed with the first current collector and the second current collector.

[0168] By integrally forming the pole piece connection portion 203 with the first current collector and the second current collector, the preparation of the first current collector, the pole piece connection portion 203 and the second current collector can be facilitated, and the connection strength between the first sub-pole piece 201 and the second sub-pole piece 202 is higher and the relative position is more stable.

[0169] In some embodiments, a first active material layer is disposed on the surface of the first current collector, a second active material layer is disposed on the surface of the second current collector, and the pole piece connecting portion 203 is an empty foil area.

[0170] By providing a first active material layer on the surface of the first current collector and a second active material layer on the surface of the second current collector, and the pole piece connecting portion 203 being a hollow foil area, the pole piece connecting portion 203 can realize electrical connection between the first sub-pole piece 201 and the second sub-pole piece 202, and the thickness of the pole piece connecting portion 203 is small, which is convenient for bending.

[0171] 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.

[0172] 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: An electrode assembly is included, wherein the electrode assembly includes a first electrode sheet group and a second electrode sheet group stacked along a first direction, the size of the first electrode sheet group along the second direction is larger than the size of the second electrode sheet group along the second direction, and the first direction is perpendicular to the second direction; The first electrode sheet group includes a first positive electrode sheet and a first negative electrode sheet stacked along the first direction, the first positive electrode sheet includes a first positive electrode collector, and the first negative electrode sheet includes a first negative electrode collector; The second electrode sheet group includes a second positive electrode sheet and a second negative electrode sheet stacked along the first direction, the second positive electrode sheet includes a second positive electrode collector, and the second negative electrode sheet includes a second negative electrode collector; The electrode assembly includes a first pole piece connection portion and a second pole piece connection portion, the first pole piece connection portion connects the first positive electrode collector and the second positive electrode collector, and the first positive electrode collector, the first pole piece connection portion, and the second positive electrode collector are integrally formed; the second pole piece connection portion connects the first negative electrode collector and the second negative electrode collector, and the first negative electrode collector, the second pole piece connection portion, and the second negative electrode collector are integrally formed.

2. The battery cell according to claim 1, characterized in that: A first separator is disposed between the first negative electrode sheet and the first positive electrode sheet, and a second separator is disposed between the second negative electrode sheet and the second positive electrode sheet; The electrode assembly includes a first diaphragm connecting portion, the first diaphragm connecting portion connects the first diaphragm and the second diaphragm, and the first diaphragm, the first diaphragm connecting portion, and the second diaphragm are integrally formed; The first diaphragm connecting portion is disposed between the first pole piece connecting portion and the second pole piece connecting portion.

3. The battery cell according to claim 2, characterized in that: The first electrode sheet connecting portion connects one side of the first positive electrode current collector along the second direction and one side of the second positive electrode current collector along the second direction; The second electrode sheet connecting portion connects one side of the first negative electrode current collector along the second direction and one side of the second negative electrode current collector along the second direction.

4. The battery cell according to claim 3, characterized in that: Along the third direction, the length of the first diaphragm connecting portion is greater than or equal to the length of the first pole piece connecting portion, and / or the length of the first diaphragm connecting portion is greater than or equal to the length of the second pole piece connecting portion; The first direction, the second direction and the third direction are perpendicular to each other.

5. The battery cell according to claim 3, characterized in that: Along the third direction, the length of the first positive electrode sheet is L2, the length of the second positive electrode sheet is L3, and the length of the first electrode sheet connecting portion is L1, satisfying 0.1≤L1 / L2≤1; 0.1≤L1 / L3≤1; The first direction, the second direction and the third direction are perpendicular to each other.

6. The battery cell according to claim 2, characterized in that: The first electrode sheet connecting portion connects one side of the first positive electrode current collector along the third direction and one side of the second positive electrode current collector along the third direction; The second electrode sheet connecting portion is connected to one side of the first negative electrode current collector along the third direction and one side of the second negative electrode current collector along the third direction; The first direction, the second direction and the third direction are perpendicular to each other.

7. The battery cell according to claim 6, characterized in that: Along the second direction, the length of the first diaphragm connecting portion is greater than or equal to the length of the first pole piece connecting portion, and / or the length of the first diaphragm connecting portion is greater than or equal to the length of the second pole piece connecting portion.

8. The battery cell according to claim 6, characterized in that: Along the second direction, the width of the first electrode sheet connecting portion is W1, the width of the first positive electrode sheet is W2, and the width of the second positive electrode sheet is W3, satisfying 0.1≤W1 / W2≤1; 0.1≤W1 / W3≤1.

9. The battery cell according to claim 1, characterized in that: The first pole piece connection portion is connected to one side of the first positive electrode current collector along the second direction / or the third direction, the second pole piece connection portion is connected to one side of the first negative electrode current collector along the second direction / or the third direction, and the first pole piece connection portion and the second pole piece connection portion are located on different sides of the electrode assembly; The first direction, the second direction and the third direction are perpendicular to each other.

10. The battery cell according to claim 9, characterized in that: A first pole lug and a second pole lug extend from one end of the battery cell along the third direction, and the first pole piece connecting portion or the second pole piece connecting portion is arranged between the first pole lug and the second pole lug.

11. The battery cell according to claim 9, characterized in that: The first electrode sheet group includes a plurality of the first positive electrode sheets and a plurality of the first negative electrode sheets, the second electrode sheet group includes a plurality of the second positive electrode sheets and a plurality of the second negative electrode sheets, each of the first positive electrode sheets is connected to a second positive electrode sheet via a first electrode sheet connecting portion, and each of the first negative electrode sheets is connected to a second negative electrode sheet via a second electrode sheet connecting portion; A plurality of the first pole piece connection portions are located on the same side of the electrode assembly, and a plurality of the second pole piece connection portions are located on the same side of the electrode assembly.

12. The battery cell according to claim 1, characterized in that: The first pole piece group also includes a first end pole piece, which is the pole piece in the first pole piece group closest to the second pole piece group, and the first positive pole piece and the first negative pole piece are both located on the side of the first end pole piece away from the second pole piece group.

13. The battery cell according to claim 12, characterized in that: A third diaphragm and a fourth diaphragm are respectively provided on both sides of the first end pole piece in the thickness direction; The electrode assembly includes a second diaphragm connecting portion, the second diaphragm connecting portion connects the third diaphragm and the fourth diaphragm, and the third diaphragm, the second diaphragm connecting portion, and the fourth diaphragm are integrally formed; The second diaphragm connecting portion is located on a side of the first end pole piece close to the second pole piece connecting portion.

14. The battery cell according to claim 13, characterized in that: The first end electrode sheet is a positive electrode sheet, the third diaphragm is arranged between the first end electrode sheet and the first negative electrode sheet, and the fourth diaphragm is arranged between the first end electrode sheet and the second negative electrode sheet.

15. The battery cell according to claim 12, characterized in that: The first pole piece connecting portion is bent around the first end pole piece; The second pole piece connecting portion is bent around the first end pole piece.

16. The battery cell according to claim 1, characterized in that: The electrode assembly also includes a first positive electrode tab and a first negative electrode tab; The first positive electrode tab is connected to one end of the first positive electrode sheet along the third direction, and the first positive electrode sheet and the second positive electrode sheet share the first positive electrode tab; The first negative electrode tab is connected to one end of the first negative electrode sheet along the third direction, and the first negative electrode sheet and the second negative electrode sheet share the second negative electrode tab; The first direction, the second direction and the third direction are perpendicular to each other.

17. The battery cell according to claim 16, characterized in that: The first electrode group further includes a third positive electrode sheet and a third negative electrode sheet stacked along the first direction; Along the first direction, the third positive electrode sheet and the third negative electrode sheet are arranged on a side of the first positive electrode sheet and the first negative electrode sheet away from the second electrode sheet group.

18. The battery cell according to claim 17, characterized in that: The electrode assembly further includes a second positive electrode tab and a second negative electrode tab; The second positive electrode tab is connected to one end of the third positive electrode sheet along the third direction, and along the first direction, the first positive electrode tab and the second positive electrode tab at least partially overlap and are connected; The second negative electrode tab is connected to one end of the third negative electrode plate along the third direction, and along the first direction, the first negative electrode tab and the second negative electrode tab at least partially overlap and are connected; The battery cell also includes a packaging, a first electrical connector and a second electrical connector. The electrode assembly is accommodated in the packaging, one end of the first electrical connector is connected to the first positive electrode tab and the second positive electrode tab, and the other end extends out of the packaging; one end of the second electrical connector is connected to the first negative electrode tab and the second negative electrode tab, and the other end extends out of the packaging.

19. The battery cell according to claim 16, characterized in that: Along the first direction, the first pole piece group includes a first portion overlapping with the second pole piece group and a second portion not overlapping with the second pole piece group; Along the third direction, a projection of the first positive electrode tab and / or a projection of the first negative electrode tab overlaps with the second portion.

20. The battery cell according to claim 1, characterized in that: The battery cell further includes a packaging member, the packaging member includes a main body, the main body includes a first main body and a second main body, the first main body and the second main body are arranged side by side along the second direction, the second main body has a first outer surface in the first direction, and the first main body protrudes from the first outer surface; When viewed along the first direction, the first pole piece group includes a first portion overlapping with the second pole piece group and a second portion not overlapping with the second pole piece group, and the first portion and the second portion are arranged and connected along the second direction; The first part and the second pole piece group are accommodated in the first main body, and the second part is accommodated in the second main body.

21. An electrical equipment, characterized in that: The invention comprises a battery cell as described in any one of claims 1 to 20, wherein the battery cell is used to provide electrical energy.

22. A pole piece, characterized in that: It includes a first sub-pole piece, a second sub-pole piece and a pole piece connecting portion, the size of the first sub-pole piece along the second direction is larger than the size of the second sub-pole piece along the second direction, the first sub-pole piece includes a first current collector, the second sub-pole piece includes a second current collector, and the pole piece connecting portion connects the first current collector and the second current collector.

23. The pole piece according to claim 22, characterized in that: The pole piece connecting portion is integrally formed with the first current collector and the second current collector.

24. The pole piece according to claim 23, characterized in that: A first active material layer is disposed on the surface of the first current collector, a second active material layer is disposed on the surface of the second current collector, and the pole piece connecting portion is a hollow foil area.

Images