Battery cell and electric device
By setting slits at the edge of the separator and designing a stacked structure for the empty foil area of the electrode, the short circuit problem caused by separator deformation in the stacked cell was solved, improving the cell's safety and energy density.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NINGDE AMPEREX TECHNOLOGY LTD
- Filing Date
- 2025-03-18
- Publication Date
- 2026-07-16
AI Technical Summary
In a laminated battery cell, when multiple positive or negative tabs are brought together, the edge of the separator may be bent and deformed, causing a short circuit between the positive and negative electrode plates, which poses a risk of thermal runaway and affects the safety of the battery cell.
A cut is made at the edge of the diaphragm, and the empty foil areas of multiple first electrodes are stacked along the first direction. The cut design reduces the deformation of the diaphragm edge, ensures the insulation effect between the diaphragm and the electrodes, and avoids short circuits.
This reduces the possibility of short circuits at electrode contacts, lowers the risk of thermal runaway in the battery cell, and improves the safety and energy density of the battery cell.
Smart Images
Figure CN2025083236_16072026_PF_FP_ABST
Abstract
Description
Battery cells and electrical equipment Cross-references to related applications
[0001] This application claims priority to Chinese patent application CN202410383564.1 entitled "Battery Cell and Electrical Equipment", filed on March 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of battery technology, and more specifically, to a battery cell and an electrical device. Background Technology
[0003] With the rapid development of electronic information technology, various electronic devices are also developing towards intelligence and multi-functionality, and the requirements for battery safety are becoming increasingly stringent.
[0004] Currently, electrode assemblies generally consist of positive and negative electrodes, with a separator placed between them to achieve insulation. However, in laminated cells, when multiple positive or negative tabs converge along the stacking direction of the positive and negative electrodes, they act on the separator, causing its edges to bend and deform. This can lead to short circuits between the positive and negative electrodes, potentially causing thermal runaway and other problems that affect the cell's safety. Summary of the Invention
[0005] This application provides a battery cell and an electrical device that can effectively improve the safety of the battery cell.
[0006] In a first aspect, embodiments of this application provide a battery cell, including an electrode assembly. The electrode assembly has a stacked structure, comprising a plurality of first electrodes and a plurality of second electrodes, which are stacked along a first direction, with the first electrodes and second electrodes having opposite polarities. Each first electrode includes a first current collector and a first active material layer. The first current collector includes a first coating area and a first empty foil area. The surface of the first coating area is provided with the first active material layer, while the surface of the first empty foil area is not provided with the first active material layer. The electrode assembly also includes a separator, which is disposed between the first electrodes and the second electrodes. The first empty foil area extends beyond the separator along a second direction, and the first empty foil areas of the plurality of first electrodes are stacked and converged along the first direction. The separator has an edge extending beyond the first coating area along the second direction, and a cut is provided on the edge. The cut is located on the side of the first empty foil area closer to the first coating area in a third direction, with the first direction, the second direction, and the third direction being perpendicular to each other.
[0007] In the above technical solution, the separator is disposed between the first electrode and the second electrode, which can serve as an insulator between the first electrode and the second electrode. The first empty foil area extends beyond the separator in the second direction, and the first empty foil areas of multiple first electrodes are stacked and closed in the first direction, which facilitates the lead-out of the battery cell from the first empty foil area to realize the electrical connection between the battery cell and the load. By providing a cut at the edge of the separator, the cut is located on the side of the first empty foil area in the third direction close to the first coating area, so that when the first empty foil areas of multiple first electrodes are closed, the part of the edge of the separator that overlaps with the first empty foil area bends with the first empty foil area as the first empty foil area is closed, while the other part of the edge of the separator is not easily deformed, so as to remain between the first electrode and the second electrode, which can reduce the possibility of short circuit between the first electrode and the second electrode, thereby reducing the risk of thermal runaway of the battery cell and improving the safety of the battery cell.
[0008] In some embodiments of this application, along the first direction, the projection of the diaphragm and the projection of the first empty foil area have an overlapping region, and along the second direction, the length of the overlapping region is L1, the length of the cut is L2, and L2≤L1 is satisfied.
[0009] In the above technical solution, by ensuring that the length L1 of the overlapping area and the length L2 of the cut satisfy L2≤L1 along the second direction, the cut does not extend beyond the edge of the separator, and the separator can cover the first coating area. This reduces the possibility of short circuit between the first electrode and the second electrode, thereby reducing the risk of thermal runaway in the battery cell and improving the safety of the battery cell.
[0010] In some embodiments of this application, along a first direction, the edges of the two diaphragms located on both sides of the first electrode are connected to each other.
[0011] In the above technical solution, by connecting the edges of the two diaphragms located on both sides of the first electrode along the first direction, the possibility of the first electrode contacting the second electrode or the cell casing can be reduced, thereby reducing the possibility of a short circuit between the first electrode and the second electrode, and thus reducing the risk of thermal runaway in the cell and improving the safety of the cell.
[0012] In some embodiments of this application, along a third direction, the first empty foil area and the first coated area have a space between them, and along a first direction, the projection of the cut falls into the space between them.
[0013] In the above technical solution, along the third direction, the first empty foil area and the first coated area have a space between them, which makes it difficult for the first coated area to deform when multiple first empty foil areas are closed. Along the first direction, the projection of the cut falls into the space between them, which can separate the part of the edge of the separator that overlaps with the first empty foil area and the part that overlaps with the first coated area. This makes the part of the edge of the separator that overlaps with the first empty foil area bend as the first empty foil area is closed, while the part of the edge of the separator that overlaps with the first coated area is not prone to deformation. This can reduce the possibility of short circuit between the first electrode and the second electrode, thereby reducing the risk of thermal runaway of the cell and improving the safety of the cell.
[0014] In some embodiments of this application, the first coating area has a first edge at one end in the second direction and a second edge at the other end in the third direction. The first coating area also has a third edge and a fourth edge connected together. The third edge is connected to the first edge, and the fourth edge is connected to the second edge. The edge at which the first coating area intersects with the first empty foil area in the second direction is the fourth edge. In the third direction, a gap space is formed between the first empty foil area and the third edge. The third edge is inclined relative to the second direction. In the direction away from the fourth edge, the width of the gap space gradually increases in the third direction.
[0015] In the above technical solution, by making the third edge inclined relative to the second direction, and gradually increasing the width of the spacing space in the third direction away from the fourth edge, the possibility of multiple first empty foil areas short-circuiting with the second electrode during the shrinking deformation process can be reduced, thereby reducing the risk of thermal runaway of the battery cell and improving the safety of the battery cell.
[0016] In some embodiments of this application, the first corner of the second electrode has a first notch, and when viewed along a first direction, the first empty foil area at least partially overlaps with the first notch.
[0017] In the above technical solution, by ensuring that the first empty foil area and the first notch at least partially overlap when viewed along the first direction, the volume of the first empty foil area protruding from the first coating area can be reduced. The space reserved between the electrode assembly and the cell housing for accommodating the first empty foil area is reduced, which can improve the energy density of the cell. Furthermore, when the cell is subjected to external force or drops, the electrode assembly is less likely to shake relative to the cell housing, and the possibility of the first empty foil area short-circuiting with the second electrode is also less, thereby reducing the risk of thermal runaway of the cell and improving the safety of the cell.
[0018] In some embodiments of this application, the second corner of the first electrode has a second notch, and when viewed along the first direction, the first notch and the second notch do not overlap; the second electrode includes a second empty foil area, and when viewed along the first direction, the second empty foil area at least partially overlaps with the second notch, and the second empty foil areas of a plurality of second electrodes are stacked and converged along the first direction.
[0019] In the above technical solution, when viewed along the first direction, the first notch and the second notch do not overlap, and the second empty foil area overlaps with the second notch at least partially, which can reduce the possibility of short circuit caused by contact between the first empty foil area and the second empty foil area; the second empty foil areas of multiple second electrodes are stacked and gathered along the first direction, which can facilitate the lead-out of the battery cell from the second empty foil area to realize the electrical connection between the battery cell and the load.
[0020] In some embodiments of this application, the diaphragm has a third notch and a fourth notch, and when viewed along a first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch.
[0021] In the above technical solution, the diaphragm has a third notch and a fourth notch. When viewed along the first direction, the first empty foil area overlaps at least partially with the third notch, and the second empty foil area overlaps at least partially with the fourth notch, so that the third notch can be used to accommodate the first empty foil area and the fourth notch can be used to accommodate the second empty foil area, which facilitates the connection of multiple first empty foil areas and multiple second empty foil areas respectively.
[0022] In some embodiments of this application, an insulating layer is provided on the first empty foil area, and the insulating layer is connected to the first active material layer.
[0023] In the above technical solution, by setting an insulating layer on the first empty foil area, the insulating layer is connected to the first active material layer, which can play an insulating role between the first empty foil area and the second electrode, reducing the possibility of the burrs on the end face of the second electrode that extends beyond the first coating area coming into contact with the first empty foil area and short-circuiting. In addition, the insulating layer can reduce the possibility of the first empty foil area coming into contact with the second electrode after it is closed, thereby reducing the possibility of thermal runaway of the battery cell and improving the safety of the battery cell.
[0024] In some embodiments of this application, the insulating layer extends beyond the edge of the diaphragm along the second direction.
[0025] In the above technical solution, by making the insulating layer extend beyond the edge of the separator along the second direction, the possibility of the burrs on the end face of the second electrode extending beyond the first coating area coming into contact with the first empty foil area and short-circuiting can be further reduced. In addition, the insulating layer can reduce the possibility of the first empty foil area coming into contact with the second electrode after it is closed, thereby reducing the possibility of thermal runaway of the battery cell and improving the safety of the battery cell.
[0026] In some embodiments of this application, along the first direction, the projection of the diaphragm and the projection of the first empty foil area have an overlapping region, and along the second direction, the length of the overlapping region is L1, and the length of the insulating layer is L3, satisfying L3 > L1.
[0027] In the above technical solution, by ensuring that the length L1 of the overlapping area and the length L3 of the insulating layer satisfy L3 > L1 along the second direction, the possibility of the burrs on the end face of the second electrode extending beyond the first coating area coming into contact with the first empty foil area and short-circuiting can be further reduced. In addition, the insulating layer can reduce the possibility of the first empty foil area coming into contact with the second electrode after it is closed, thereby reducing the possibility of thermal runaway of the battery cell and improving the safety of the battery cell.
[0028] In some embodiments of this application, the thickness of the insulating layer is H1, and the thickness of the first active material layer is H2, satisfying H1≤H2.
[0029] In the above technical solution, by ensuring that the thickness H1 of the insulating layer and the thickness H2 of the first active material layer satisfy H1≤H2, the insulating layer does not exceed the first active material layer in the thickness direction. This ensures that setting the insulating layer does not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell.
[0030] In some embodiments of this application, the thickness of the insulating layer is H, which satisfies 0.005mm≤H≤0.1mm.
[0031] In the above technical solution, when the thickness H of the insulating layer is greater than or equal to 0.005 mm, the insulation layer is thicker, resulting in better insulation between the first empty foil area and the second electrode, higher insulation reliability, and a reduced possibility of short circuit between the first empty foil area and the second electrode, thereby reducing the possibility of thermal runaway in the battery cell. When the thickness H of the insulating layer is less than or equal to 0.1 mm, the insulation layer does not extend beyond the first active material layer in the thickness direction, thus the addition of the insulating adhesive layer does not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell. Therefore, when the thickness H of the insulating layer is between 0.005 mm and 0.1 mm, it not only provides better insulation between the first empty foil area and the second electrode, higher insulation reliability, and reduces the possibility of short circuit between the first empty foil area and the second electrode, thereby reducing the possibility of thermal runaway in the battery cell, but also ensures that the insulation layer does not extend beyond the first active material layer in the thickness direction, thus the addition of the insulating layer does not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell.
[0032] In some embodiments of this application, 0.01mm ≤ H ≤ 0.05mm.
[0033] In the above technical solution, when the thickness H of the insulating layer is greater than or equal to 0.01 mm, the insulation layer can be made thicker, resulting in better insulation between the first empty foil area and the second electrode, higher insulation reliability, and a reduced possibility of short circuit between the first empty foil area and the second electrode, thereby reducing the possibility of thermal runaway in the battery cell. When the thickness H of the insulating layer is less than or equal to 0.05 mm, the insulation layer does not exceed the first active material layer in the thickness direction, so that the addition of the insulating adhesive layer does not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell. Therefore, when the thickness H of the insulating layer is 0.01 mm to 0.05 mm, it can not only further improve the insulation effect between the first empty foil area and the second electrode, resulting in higher insulation reliability and a reduced possibility of short circuit between the first empty foil area and the second electrode, thus reducing the possibility of thermal runaway in the battery cell, but also ensure that the insulation layer does not exceed the first active material layer in the thickness direction, so that the addition of the insulating layer does not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell.
[0034] In some embodiments of this application, the insulating layer includes polymeric materials and auxiliary materials. The polymeric materials include at least one of ethylene, propylene, vinylidene fluoride, acrylic acid, acrylate, styrene, acrylonitrile, polyamide, maleic anhydride, vinyl chloride, and propylene chloride. The auxiliary materials include carboxymethyl cellulose and polyoxyethylene ether.
[0035] In the above technical solution, the insulating layer includes polymer materials and auxiliary materials. The polymer materials include at least one of ethylene, propylene, vinylidene fluoride, acrylic acid, acrylate, styrene, acrylonitrile, polyamide, maleic anhydride, vinyl chloride, and propylene chloride. The auxiliary materials include carboxymethyl cellulose and polyoxyethylene ether. This allows the insulating layer to have low hardness, making it less likely to be damaged when the first empty foil area is retracted. It also allows the insulating layer to adhere to the separator, reducing the possibility of the separator's edges lifting when subjected to external force or falling, thereby reducing the possibility of short circuit between the first electrode and the second electrode, reducing the possibility of thermal runaway in the battery cell, and improving the safety of the battery cell. Furthermore, it makes the preparation of the insulating layer less difficult and less costly, and the insulating layer can be attached to the first empty foil area in different shapes, thus having a wide range of applications.
[0036] In some embodiments of this application, the first electrode is a positive electrode and the second electrode is a negative electrode.
[0037] Secondly, embodiments of this application provide an electrical device, including a battery cell as described above, the battery cell being used to provide electrical energy. Attached Figure Description
[0038] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0039] Figure 1 is a three-dimensional structural diagram of a battery cell provided in some embodiments of this application;
[0040] Figure 2 is a three-dimensional structural schematic diagram of the electrode assembly of the battery cell provided in some embodiments of this application;
[0041] Figure 3 is an exploded structural diagram of the electrode assembly of a battery cell provided in some embodiments of this application;
[0042] Figure 4 is a schematic diagram of the structure of the first electrode of the battery cell provided in some embodiments of this application;
[0043] Figure 5 is a schematic diagram of the structure of the first current collector of the battery cell provided in some embodiments of this application;
[0044] Figure 6 is a schematic diagram of a partial structure of a battery cell provided in some embodiments of this application;
[0045] Figure 7 is a partially enlarged structural diagram of point A in the battery cell in Figure 6;
[0046] Figure 8 is a cross-sectional schematic diagram of a portion of the structure of a battery cell provided in some embodiments of this application;
[0047] Figure 9 is a schematic diagram of the structure of the second electrode of the battery cell provided in some embodiments of this application;
[0048] Figure 10 is a schematic diagram of the structure of the second current collector of the battery cell provided in some embodiments of this application;
[0049] Figure 11 is a schematic diagram of the structure of the separator of the battery cell provided in some embodiments of this application;
[0050] Figure 12 is a schematic diagram of a partial structure of a battery cell provided in some other embodiments of this application;
[0051] Figure 13 is a partially enlarged structural diagram of point B in the battery cell in Figure 12.
[0052] Icons: 10-Battery cell; 100-Electrode assembly; 110-First electrode; 110a-Second notch; 111-First current collector; 1111-First coating area; 1111a-First edge; 1111b-Second edge; 1111c-Third edge; 1111d-Fourth edge; 1112-First empty foil area; 112-First active material layer; 120-Second electrode; 120a-First notch; 121-Second current collector; 1211-Second coating area; 1212-Second empty foil area; 122-Second active material layer; 130-Separator; 130a-Third notch; 130b-Fourth notch; 131-Edge portion; 1311-Cutout; 1312-Second cutout; 140-Insulating layer; 150-Second insulating layer; 200-Battery cell casing; X-First direction; Y-Second direction; Z-Third direction. Specific embodiments.
[0053] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.
[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having" and any variations thereof in the specification, claims and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0055] The terms "first," "second," etc., in the specification, claims, or the accompanying drawings of this application are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.
[0056] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.
[0057] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.
[0058] A battery typically consists of a positive electrode, a negative electrode, and a separator. The separator is positioned between the positive and negative electrodes to provide insulation between them. With the development of the new energy industry, batteries are increasingly moving towards higher energy density and power density, resulting in more compact internal structures. If the separator deforms, it can cause direct contact between the positive and negative electrodes, leading to short circuits and thermal runaway within the cell. In stacked battery structures, the deformation of multiple positive or negative tabs when they are brought together acts on the separator, causing its edges to bend and deform, posing a safety hazard. The tabs are brought together by pressing them together along their thickness direction, facilitating welding and connection to external electrical connectors.
[0059] To improve the safety of the battery cell, this application provides a battery cell including an electrode assembly. The electrode assembly has a stacked structure and includes multiple first electrodes and multiple second electrodes. The multiple first electrodes and multiple second electrodes are stacked along a first direction, and the polarities of the first electrodes and second electrodes are opposite. The first electrode includes a first current collector and a first active material layer. The first current collector includes a first coating area and a first empty foil area. The surface of the first coating area is provided with the first active material layer, and the surface of the first empty foil area is not provided with the first active material layer. The electrode assembly also includes a separator, which is disposed between the first electrodes and the second electrodes. The first empty foil area extends beyond the separator along a second direction. The first empty foil areas of the multiple first electrodes are stacked and converged along the first direction. The separator has an edge portion extending beyond the first coating area along the second direction. A cut is provided on the edge portion. The cut is located on the side of the first empty foil area closer to the first coating area in a third direction. The first direction, the second direction, and the third direction are perpendicular to each other.
[0060] In this type of battery cell, a separator is positioned between the first and second electrodes, providing insulation between them. A first empty foil area extends beyond the separator in a second direction, and multiple first empty foil areas of the first electrodes are stacked and converged in a first direction, facilitating the lead-out of the first empty foil area from the battery cell to achieve electrical connection between the battery cell and the load. By providing a cut at the edge of the separator, located on the side of the first empty foil area closer to the first coating area in a third direction, when the first empty foil areas of the multiple first electrodes converge, the overlapping portion of the separator's edge with the first empty foil area bends as the first empty foil area converges, while other parts of the separator's edge are less prone to deformation, thus maintaining a connection between the first and second electrodes. This reduces the possibility of a short circuit between the first and second electrodes, thereby reducing the risk of thermal runaway and improving the battery cell's safety.
[0061] The battery cell provided in this application embodiment can be a secondary battery or a primary battery, such as a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., and this application embodiment is not limited in this respect. The electrochemical device can be cylindrical, flat, cuboid, or other shapes, etc., and this application embodiment is not limited in this respect either.
[0062] This application provides an electrical device that uses battery cells as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc.
[0063] Referring to Figures 1 to 7, Figure 1 is a three-dimensional structural schematic diagram of a battery cell provided in some embodiments of this application; Figure 2 is a three-dimensional structural schematic diagram of an electrode assembly of a battery cell provided in some embodiments of this application; Figure 3 is an exploded structural schematic diagram of an electrode assembly of a battery cell provided in some embodiments of this application; Figure 4 is a structural schematic diagram of the first electrode plate of a battery cell provided in some embodiments of this application; Figure 5 is a structural schematic diagram of the first current collector of a battery cell provided in some embodiments of this application; Figure 6 is a schematic diagram of a partial structure of a battery cell provided in some embodiments of this application; and Figure 7 is a partially enlarged structural schematic diagram of point A of the battery cell in Figure 6.
[0064] This application provides a battery cell 10, which includes an electrode assembly 100. The electrode assembly 100 has a stacked structure and includes a plurality of first electrode plates 110 and a plurality of second electrode plates 120. The plurality of first electrode plates 110 and the plurality of second electrode plates 120 are stacked along a first direction X, and the polarities of the first electrode plates 110 and the second electrode plates 120 are opposite.
[0065] In some embodiments, the first electrode 110 includes a first current collector 111 and a first active material layer 112. The first current collector 111 includes a first coating area 1111 and a first empty foil area 1112. The surface of the first coating area 1111 is provided with the first active material layer 112, and the surface of the first empty foil area 1112 is not provided with the first active material layer 112.
[0066] In some embodiments, the electrode assembly 100 further includes a diaphragm 130 disposed between the first electrode 110 and the second electrode 120, with a first empty foil region 1112 extending beyond the diaphragm 130 along the second direction Y, and the first empty foil regions 1112 of the plurality of first electrodes 110 being stacked and converged along the first direction X.
[0067] By placing the diaphragm 130 between the first electrode 110 and the second electrode 120, insulation can be provided between the first electrode 110 and the second electrode 120. The first empty foil area 1112 extends beyond the diaphragm 130 along the second direction Y. The first empty foil areas 1112 of the multiple first electrodes 110 are stacked and gathered along the first direction X, which facilitates the lead-out of the battery cell 10 from the first empty foil area 1112 to realize the electrical connection between the battery cell 10 and the load.
[0068] In some embodiments, the diaphragm 130 has an edge portion 131 extending beyond the first coating area 1111 along the second direction Y. A cut 1311 is provided on the edge portion 131. The cut 1311 is located on the side of the first empty foil area 1112 in the third direction Z that is close to the first coating area 1111. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.
[0069] By providing a cut 1311 at the edge 131 of the diaphragm 130, with the cut 1311 located on the side of the first empty foil area 1112 in the third direction Z that is close to the first coating area 1111, when the first empty foil areas 1112 of the multiple first electrodes 110 are closed, the overlapping portion of the edge 131 of the diaphragm 130 and the first empty foil area 1112 bends as the first empty foil area 1112 closes, while the other portion of the edge 131 of the diaphragm 130 is less prone to deformation, thus remaining between the first electrode 110 and the second electrode 120. This reduces the possibility of a short circuit between the first electrode 110 and the second electrode 120, thereby reducing the risk of thermal runaway in the cell 10 and improving the safety of the cell 10.
[0070] In some embodiments, referring to FIG7, along the first direction X, the projection of the diaphragm 130 and the projection of the first empty foil area 1112 overlap, and along the second direction Y, the length of the overlapping area is L1, and the length of the cut 1311 is L2, satisfying L2≤L1. For example, L2 can be L1, 0.9*L1, or 0.8*L1, etc.
[0071] By ensuring that the length L1 of the overlapping area and the length L2 of the cut 1311 along the second direction Y satisfy L2≤L1, the cut 1311 does not extend beyond the edge 131 of the diaphragm 130, and the diaphragm 130 can cover the first coating area 1111. This reduces the possibility of a short circuit between the first electrode 110 and the second electrode 120, thereby reducing the risk of thermal runaway in the cell 10 and improving the safety of the cell 10.
[0072] Referring to Figure 8, Figure 8 is a cross-sectional schematic diagram of a portion of the structure of a battery cell provided in some embodiments of this application.
[0073] In some embodiments, along the first direction X, the edges 131 of the two diaphragms 130 located on both sides of the first electrode 110 are connected to each other.
[0074] By connecting the edges 131 of the two diaphragms 130 located on both sides of the first electrode 110 along the first direction X, the possibility of the first electrode 110 contacting the second electrode 120 or the cell housing 200 can be reduced, thereby reducing the possibility of a short circuit between the first electrode 110 and the second electrode 120, and thus reducing the risk of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0075] In some embodiments, the first electrode 110 is a positive electrode and the second electrode 120 is a negative electrode.
[0076] In a hard-shell battery cell, the negative electrode can be electrically connected to the load through the cell housing 200, and the second electrode 120 can be electrically connected to the cell housing 200. By connecting the edges 131 of the two layers of separators 130 located on both sides of the first electrode 110 along the first direction X, the possibility of short circuit caused by contact between the positive electrode and the cell housing 200 can be reduced, thereby reducing the risk of thermal runaway of the battery cell 10 and improving the safety of the battery cell 10.
[0077] In other embodiments, along the first direction X, the edges 131 of the two diaphragms 130 located on both sides of the second electrode 120 are connected to each other.
[0078] By connecting the edges 131 of the two diaphragms 130 located on both sides of the second electrode 120 along the first direction X, the possibility of the first electrode 110 contacting the second electrode 120 or the cell housing 200 can be reduced, thereby reducing the possibility of a short circuit between the first electrode 110 and the second electrode 120, and thus reducing the risk of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0079] Since the potential difference between the negative electrode and the cell housing 200 in the pouch cell is greater than that between the positive electrode and the cell housing 200, the possibility of corrosion of the cell housing 200 is relatively high if the negative electrode comes into contact with it. By connecting the edges 131 of the two diaphragms 130 on both sides of the second electrode 120 along the first direction X, the possibility of corrosion of the cell housing 200 due to contact between the negative electrode and the cell housing 200 can be reduced, which is beneficial to extending the service life of the cell 10.
[0080] In some embodiments, along the third direction Z, the first empty foil area 1112 and the first coating area 1111 have a space between them, and along the first direction X, the projection of the cut 1311 falls into the space between them.
[0081] By creating a gap between the first empty foil area 1112 and the first coated area 1111 along the third direction Z, the first coated area 1111 is less likely to deform when multiple first empty foil areas 1112 are closed. Along the first direction X, the projection of the cut 1311 falls into the gap, separating the portion of the edge portion 131 of the separator 130 that overlaps with the first empty foil area 1112 from the portion that overlaps with the first coated area 1111. This makes the overlapping portion of the edge portion 131 of the separator 130 with the first empty foil area 1112 less likely to deform as the first empty foil area 1112 is closed and bent, thus reducing the possibility of a short circuit between the first electrode 110 and the second electrode 120, thereby reducing the risk of thermal runaway in the cell 10 and improving the safety of the cell 10.
[0082] In some embodiments, referring to FIG4, the first coating area 1111 has a first edge 1111a at one end in the second direction Y and a second edge 1111b at one end in the third direction Z. The first coating area 1111 also has a connected third edge 1111c and a fourth edge 1111d, the third edge 1111c being connected to the first edge 1111a and the fourth edge 1111d being connected to the second edge 1111b.
[0083] The edge where the first coated area 1111 intersects with the first empty foil area 1112 along the second direction Y is the fourth edge 1111d. Along the third direction Z, a gap space is formed between the first empty foil area 1112 and the third edge 1111c. The third edge 1111c is inclined relative to the second direction Y. Along the direction away from the fourth edge 1111d, the width of the gap space gradually increases in the third direction Z. The third edge 1111c can be straight, wavy, or curved.
[0084] By setting the third edge 1111c at an angle relative to the second direction Y, and gradually increasing the width of the spacing space in the third direction Z along the direction away from the fourth edge 1111d, the possibility of multiple first empty foil areas 1112 coming into contact with the second electrode 120 and short-circuiting during the shrinking deformation process can be reduced, thereby reducing the risk of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0085] In some embodiments, the first corner of the second electrode 120 has a first notch 120a, and when viewed along the first direction X, the first empty foil area 1112 at least partially overlaps with the first notch 120a.
[0086] In this application, "corner position" refers to the position at the top corner of the electrode. For example, the first empty foil area 1112 is located at the first electrode 110, that is, the two edges and one corner of the first empty foil area 1112 coincide with two edges and one corner of the first electrode 110.
[0087] In some embodiments, the first corner position of the second electrode 120 is the position at one of the apex corners of the second electrode 120.
[0088] By ensuring that the first empty foil area 1112 at least partially overlaps with the first notch 120a when viewed along the first direction X, the volume of the first empty foil area 1112 protruding from the first coating area 1111 can be reduced. The space reserved between the electrode assembly 100 and the cell housing 200 for accommodating the first empty foil area 1112 is reduced, which can improve the energy density of the cell 10. Furthermore, when the cell 10 is subjected to external force or drops, the electrode assembly 100 is less likely to shake relative to the cell housing 200, and the possibility of the first empty foil area 1112 contacting and short-circuiting with the second electrode 120 is also less, thereby reducing the risk of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0089] In other embodiments, along the third direction Z, the first empty foil area 1112 can be disposed in the middle of the first electrode 110. Cutouts 1311 are provided on both sides of the first empty foil area 1112 along the third direction Z. This allows the overlapping portion of the edge portion 131 of the separator 130 and the first empty foil area 1112 to bend as the first empty foil area 1112 is closed when the first empty foil area 1112 is closed. The other portions of the edge portion 131 of the separator 130 are less likely to deform, so as to remain between the first electrode 110 and the second electrode 120. This can reduce the possibility of short circuit between the first electrode 110 and the second electrode 120, thereby reducing the risk of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0090] Referring to Figures 4, 9 and 10, Figure 9 is a schematic diagram of the structure of the second electrode of the battery cell provided in some embodiments of this application; Figure 10 is a schematic diagram of the structure of the second current collector of the battery cell provided in some embodiments of this application.
[0091] In some embodiments, the second electrode 120 includes a second current collector 121 and a second active material layer 122. The second current collector 121 includes a second coating area 1211 and a second empty foil area 1212. The surface of the second coating area 1211 is provided with the second active material layer 122, and the surface of the second empty foil area 1212 is not provided with the second active material layer 122.
[0092] In some embodiments, the second corner of the first electrode 110 has a second notch 110a, and when viewed along the first direction X, the first notch 120a and the second notch 110a do not overlap.
[0093] In some embodiments, the second corner position of the first electrode 110 is the position at one of the apex corners of the first electrode 110.
[0094] When viewed along the first direction X, the second empty foil area 1212 and the second notch 110a at least partially overlap, and the second empty foil areas 1212 of the plurality of second pole pieces 120 are stacked and converged along the first direction X.
[0095] By ensuring that, when viewed along the first direction X, the first notch 120a and the second notch 110a do not overlap, and the second empty foil region 1212 at least partially overlaps with the second notch 110a, the possibility of a short circuit caused by contact between the first empty foil region 1112 and the second empty foil region 1212 can be reduced. The second empty foil regions 1212 of the plurality of second electrode plates 120 are stacked and converged along the first direction X, facilitating the lead-out of the battery cell 10 from the second empty foil region 1212 to achieve electrical connection between the battery cell 10 and the load.
[0096] See Figure 11. Figure 11 is a schematic diagram of the structure of the separator of the battery cell provided in some embodiments of this application.
[0097] In some embodiments, the diaphragm 130 has a third notch 130a and a fourth notch 130b. When viewed along the first direction X, the first empty foil region 1112 at least partially overlaps with the third notch 130a, and the second empty foil region 1212 at least partially overlaps with the fourth notch 130b.
[0098] By making the diaphragm 130 have a third notch 130a and a fourth notch 130b, when viewed along the first direction X, the first empty foil region 1112 at least partially overlaps with the third notch 130a, and the second empty foil region 1212 at least partially overlaps with the fourth notch 130b, so that the third notch 130a can be used to accommodate the first empty foil region 1112, and the fourth notch 130b can be used to accommodate the second empty foil region 1212, which facilitates the connection of multiple first empty foil regions 1112 and multiple second empty foil regions 1212 respectively.
[0099] In some embodiments, along the third direction Z, the second empty foil region 1212 and the second coated region 1211 have a space between them.
[0100] By creating a space between the second empty foil region 1212 and the second coated region 1211 along the third direction Z, the second coated region 1211 is less likely to deform when multiple second empty foil regions 1212 are closed.
[0101] In some embodiments, an insulating layer 140 is provided on the first empty foil area 1112, and the insulating layer 140 is connected to the first active material layer 112.
[0102] By providing an insulating layer 140 on the first empty foil area 1112, the insulating layer 140 is connected to the first active material layer 112, which can provide insulation between the first empty foil area 1112 and the second electrode 120. This reduces the possibility of burrs on the end face of the second electrode 120 extending beyond the first coating area 1111 coming into contact with the first empty foil area 1112 and short-circuiting. Furthermore, the insulating layer 140 can reduce the possibility of the first empty foil area 1112 coming into contact with the second electrode 120 after it is closed, thereby reducing the possibility of thermal runaway in the battery cell 10 and improving the safety of the battery cell 10.
[0103] In some embodiments, along the second direction Y, the insulating layer 140 extends beyond the edge of the diaphragm 130.
[0104] By extending the insulating layer 140 beyond the edge of the diaphragm 130 along the second direction Y, the possibility of short circuits caused by burrs on the end face of the second electrode 120 extending beyond the first coating area 1111 contacting the first empty foil area 1112 can be further reduced. Furthermore, the insulating layer 140 can reduce the possibility of short circuits caused by the first empty foil area 1112 contacting the second electrode 120 after it is closed, thereby reducing the possibility of thermal runaway in the cell 10 and improving the safety of the cell 10.
[0105] In some embodiments, along the first direction X, the projection of the diaphragm 130 overlaps with the projection of the first empty foil region 1112, and along the second direction Y, the length of the overlapping region is L1, and the length of the insulating layer 140 is L3, satisfying L3 > L1. For example, L3 can be 1.1*L1, 1.3*L1, or 1.5*L1, etc.
[0106] By ensuring that the length L1 of the overlapping area and the length L3 of the insulating layer 140 along the second direction Y satisfy L3 > L1, the possibility of the burrs on the end face of the second electrode 120 extending beyond the first coating area 1111 coming into contact with the first empty foil area 1112 and short-circuiting can be further reduced. In addition, the insulating layer 140 can reduce the possibility of the first empty foil area 1112 coming into contact with the second electrode 120 and short-circuiting after it is closed, thereby reducing the possibility of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0107] In some embodiments, the thickness of the insulating layer 140 is H1, and the thickness of the first active material layer 112 is H2, satisfying H1≤H2. For example, H1 can be H2, 0.9*H2, or 0.8*H2, etc.
[0108] By ensuring that the thickness H1 of the insulating layer 140 and the thickness H2 of the first active material layer 112 satisfy H1≤H2, the insulating layer 140 can be made to not exceed the first active material layer 112 in the thickness direction. This ensures that setting the insulating layer 140 will not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the battery cell 10.
[0109] In some embodiments, the thickness of the insulating layer 140 is H, which satisfies 0.005mm ≤ H ≤ 0.1mm. For example, H can be 0.005mm, 0.03mm, or 0.1mm, etc.
[0110] When the thickness H of the insulating layer 140 is greater than or equal to 0.005 mm, the insulation layer 140 is thicker, resulting in better insulation between the first empty foil area 1112 and the second electrode 120, higher insulation reliability, and a reduced possibility of short circuit between the first empty foil area 1112 and the second electrode 120, thereby reducing the possibility of thermal runaway in the cell 10. When the thickness H of the insulating layer 140 is less than or equal to 0.1 mm, the insulation layer 140 does not exceed the first active material layer 112 in the thickness direction, so that the addition of the insulating adhesive layer does not increase the thickness of the electrode assembly 100, which is beneficial to improving... The energy density of the cell 10; therefore, when the thickness H of the insulating layer 140 is 0.005mm-0.1mm, it can not only ensure that the insulating layer 140 has a good insulation effect between the first empty foil area 1112 and the second electrode 120, and the insulation reliability is high, which can reduce the possibility of short circuit between the first empty foil area 1112 and the second electrode 120, thereby reducing the possibility of thermal runaway of the cell 10; it can also ensure that the insulating layer 140 does not exceed the first active material layer 112 in the thickness direction, so that the setting of the insulating layer 140 will not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the cell 10.
[0111] In some embodiments, 0.01mm ≤ H ≤ 0.05mm. For example, H can be 0.01mm, 0.02mm, or 0.05mm, etc.
[0112] When the thickness H of the insulating layer 140 is greater than or equal to 0.01 mm, the insulation layer 140 can be made thicker, resulting in better insulation between the first empty foil area 1112 and the second electrode 120, higher insulation reliability, and a reduced possibility of short circuit between the first empty foil area 1112 and the second electrode 120, thereby reducing the possibility of thermal runaway in the cell 10. When the thickness H of the insulating layer 140 is less than or equal to 0.05 mm, the insulation layer 140 can be made to not exceed the first active material layer 112 in the thickness direction, so that the addition of the insulating adhesive layer does not increase the thickness of the electrode assembly 100, which is beneficial to improving... The energy density of the cell 10; therefore, when the thickness H of the insulating layer 140 is 0.01mm-0.05mm, it can further improve the insulation effect between the insulating layer 140 and the first empty foil area 1112 and the second electrode 120, and increase the insulation reliability. This can reduce the possibility of short circuit between the first empty foil area 1112 and the second electrode 120, thereby reducing the possibility of thermal runaway of the cell 10. Furthermore, it can ensure that the insulating layer 140 does not exceed the first active material layer 112 in the thickness direction, so that the insulating layer 140 does not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the cell 10.
[0113] In some embodiments, the insulating layer 140 includes a polymer material and auxiliary materials. The polymer material includes at least one of ethylene, propylene, vinylidene fluoride, acrylic acid, acrylate, styrene, acrylonitrile, polyamide, maleic anhydride, vinyl chloride, and propylene chloride. The auxiliary materials include carboxymethyl cellulose and polyoxyethylene ether.
[0114] By including polymer materials and auxiliary materials in the insulating layer 140, the polymer materials include at least one of ethylene, propylene, vinylidene fluoride, acrylic acid, acrylate, styrene, acrylonitrile, polyamide, maleic anhydride, vinyl chloride, and propylene chloride, and the auxiliary materials include carboxymethyl cellulose and polyoxyethylene ether, the insulating layer 140 has a lower hardness, making it less likely to be damaged when the first empty foil area 1112 is closed; the insulating layer 140 can be bonded to the diaphragm 130, reducing the possibility of the edge portion 131 of the diaphragm 130 warping when subjected to external force or falling, thereby reducing the possibility of short circuit between the first electrode 110 and the second electrode 120, reducing the possibility of thermal runaway in the battery cell 10, and improving the safety of the battery cell 10; and the insulating layer 140 has lower manufacturing difficulty and cost, and can be attached to the first empty foil area 1112 in different shapes, thus having a wider range of applications.
[0115] Referring to Figures 12 and 13, Figure 12 is a schematic diagram of a partial structure of a battery cell provided in some other embodiments of this application; Figure 13 is a partially enlarged schematic diagram of the battery cell at point B in Figure 12.
[0116] In some other embodiments, a second cut 1312 is provided on the edge portion 131, the second cut 1312 being located on the side of the second empty foil area 1212 in the third direction Z that is close to the second coating area 1211.
[0117] By providing a second cut 1312 at the edge 131 of the diaphragm 130, the second cut 1312 is located on the side of the second empty foil area 1212 in the third direction Z that is close to the second coating area 1211. This allows the overlapping portion of the edge 131 of the diaphragm 130 and the second empty foil area 1212 to bend as the second empty foil area 1212 is closed when the second empty foil area 1212 of the multiple second electrodes 120 is closed. The other portion of the edge 131 of the diaphragm 130 is less likely to deform, so as to remain between the first electrode 110 and the second electrode 120. This reduces the possibility of short circuit between the first electrode 110 and the second electrode 120, thereby reducing the risk of thermal runaway of the cell 10 and improving the safety of the cell 10.
[0118] In some embodiments, a second insulating layer 150 is provided on the second empty foil area 1212, and the second insulating layer 150 is connected to the second active material layer 122.
[0119] By providing a second insulating layer 150 on the second empty foil area 1212, the second insulating layer 150 is connected to the second active material layer 122, which can serve as an insulation between the second empty foil area 1212 and the first electrode 110. This can reduce the possibility of the second empty foil area 1212 contacting the first electrode 110 after it is closed, thereby reducing the possibility of thermal runaway of the battery cell 10 and improving the safety of the battery cell 10.
[0120] In some embodiments, the battery cell 10 further includes a battery cell housing with a receiving space, and the electrode assembly 100 is received in the receiving space.
[0121] In some embodiments, the cell housing 100 can be made of a high-strength material, such as steel, aluminum alloy or other metal materials, so that the cell housing 100 has high load-bearing capacity, and thus the cell housing 100 is not easily deformed or damaged by stress or environmental changes, thereby making the electrochemical device 10 more reliable.
[0122] In other embodiments, the cell housing 100 may also be made of high-strength non-metallic materials such as carbon fiber or rigid plastic.
[0123] The battery cell 10 includes an electrode assembly 100, a cell housing 200, and an electrolyte. The cell housing 200 houses the electrode assembly 100 and the electrolyte. The electrode assembly 100 consists of a positive electrode, a negative electrode, and a separator. The battery cell 10 primarily operates by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the portion of the positive current collector without the positive active material layer serves as the positive electrode tab, through which electrical energy is input or output to the positive electrode. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary materials, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the portion of the negative current collector without the negative active material layer serves as the negative electrode tab, through which electrical energy is input or output. The negative current collector can be made of copper, and the negative active material can be made of carbon or silicon, etc. The separator can be made of polypropylene (PP) or polyethylene (PE), etc. The electrolyte can include organic solvents, lithium salts, etc.
[0124] Secondly, embodiments of this application provide an electrical device, including the battery cell 10 as described above, the battery cell 10 being used to provide electrical energy.
[0125] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0126] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A battery cell, characterized in that, The electrode assembly includes an electrode assembly with a stacked structure. The electrode assembly includes a plurality of first electrodes and a plurality of second electrodes, which are stacked along a first direction. The first electrodes and the second electrodes have opposite polarities. The first electrode includes a first current collector and a first active material layer. The first current collector includes a first coating area and a first empty foil area. The first active material layer is disposed on the surface of the first coating area, and the first active material layer is not disposed on the surface of the first empty foil area. The electrode assembly further includes a diaphragm disposed between the first electrode and the second electrode, the first empty foil area extending beyond the diaphragm along a second direction, and the first empty foil areas of the plurality of first electrodes stacked and converged along the first direction; The diaphragm has an edge portion extending beyond the first coating area along the second direction, and a cut is provided on the edge portion. The cut is located on the side of the first empty foil area closer to the first coating area in the third direction, and the first direction, the second direction, and the third direction are perpendicular to each other.
2. The battery cell according to claim 1, characterized in that, Along the first direction, the projection of the diaphragm overlaps with the projection of the first empty foil area. Along the second direction, the length of the overlapping area is L1, and the length of the cut is L2, satisfying L2≤L1.
3. The battery cell according to claim 1, characterized in that, Along the first direction, the edges of the two layers of the separator located on both sides of the first electrode are connected to each other.
4. The battery cell according to claim 1, characterized in that, Along the third direction, the first empty foil area and the first coated area have a space between them, and along the first direction, the projection of the cut falls into the space between them.
5. The battery cell according to claim 4, characterized in that, The first coating area has a first edge at one end in the second direction and a second edge at the other end in the third direction. The first coating area also has a third edge and a fourth edge connected together. The third edge is connected to the first edge, and the fourth edge is connected to the second edge. The edge at which the first coating area intersects with the first empty foil area in the second direction is the fourth edge. Along the third direction, the first empty foil area and the third edge form the gap space. The third edge is inclined relative to the second direction. Along the direction away from the fourth edge, the width of the gap space gradually increases in the third direction.
6. The battery cell according to claim 4, characterized in that, The first corner of the second electrode has a first notch, and when viewed along the first direction, the first empty foil area at least partially overlaps with the first notch.
7. The battery cell according to claim 6, characterized in that, The second corner of the first electrode has a second notch, and when viewed along the first direction, the first notch and the second notch do not overlap. The second electrode includes a second empty foil area. When viewed along the first direction, the second empty foil area at least partially overlaps with the second notch. The second empty foil areas of a plurality of second electrodes are stacked and converged along the first direction.
8. The battery cell according to claim 7, characterized in that, The diaphragm has a third notch and a fourth notch. When viewed along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch.
9. The battery cell according to claim 1, characterized in that, An insulating layer is provided on the first empty foil area, and the insulating layer is connected to the first active material layer.
10. The battery cell according to claim 9, characterized in that, Along the second direction, the insulating layer extends beyond the edge of the diaphragm.
11. The battery cell according to claim 9, characterized in that, Along the first direction, the projection of the diaphragm overlaps with the projection of the first empty foil area. Along the second direction, the length of the overlapping area is L1, and the length of the insulating layer is L3, satisfying L3 > L1.
12. The battery cell according to claim 9, characterized in that, The thickness of the insulating layer is H1, and the thickness of the first active material layer is H2, satisfying H1≤H2.
13. The battery cell according to claim 9, characterized in that, The thickness of the insulating layer is H, which satisfies 0.005mm≤H≤0.1mm.
14. The battery cell according to claim 13, characterized in that, 0.01mm≤H≤0.05mm.
15. The battery cell according to claim 9, characterized in that, The insulating layer comprises a polymer material and auxiliary materials. The polymer material includes at least one of ethylene, propylene, vinylidene fluoride, acrylic acid, acrylate, styrene, acrylonitrile, polyamide, maleic anhydride, vinyl chloride, and propylene chloride. The auxiliary materials include carboxymethyl cellulose and polyoxyethylene ether.
16. The battery cell according to claim 1, characterized in that, The first electrode is the positive electrode, and the second electrode is the negative electrode.
17. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-16, the battery cell being used to provide electrical energy.