Battery cell, battery device, and electric device

Abstract

The application discloses a battery monomer, a battery device and a power utilization device, relates to the technical field of batteries, and discloses a battery monomer, a battery device and a power utilization device, which belong to the technical field of batteries. The battery monomer comprises a shell and an electrode assembly. The shell is provided with an electrode terminal. The electrode assembly is arranged in the shell. The electrode assembly comprises a first pole piece. The first pole piece comprises a first current collector and an active material layer. The first current collector comprises a support base and a metal layer. The metal layer is at least partially located between the support base and the active material layer. The surface of the metal layer, which is away from the support base, is provided with the active material layer. The metal layer comprises a conductive main body part and a first protruding part which extends from the conductive main body part in a first direction. The active material layer comprises a first active material part and a second active material part. According to the battery monomer, the first active material part can play a role in stabilizing the support of the first protruding part, can reduce the probability of local overheating of the battery monomer, and is beneficial to improving the reliability of the battery monomer.

Description

Technical Field

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

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Improving the reliability of individual battery cells is a key research direction in battery technology development. Utility Model Content

[0003] This application aims to at least solve one of the technical problems existing in the prior art. To this end, one objective of this application is to provide a battery cell in which the first active material portion can stably support the first protrusion, thereby reducing the risk of metal layer cracking and failure affecting the overcurrent performance of the metal layer, reducing the probability of local overheating of the battery cell, and improving the reliability of the battery cell.

[0004] This application also proposes a battery device using the aforementioned battery cells.

[0005] This application also proposes an electrical device using the aforementioned battery device.

[0006] In a first aspect, embodiments of this application provide a battery cell, including: a casing and an electrode assembly. The casing is provided with electrode terminals, and the electrode assembly is disposed within the casing. The electrode assembly includes a first electrode sheet, which includes a first current collector and an active material layer. The first current collector includes a supporting substrate and a metal layer. The supporting substrate, the metal layer, and the active material layer are stacked along the thickness direction of the first current collector. The metal layer is at least partially located between the supporting substrate and the active material layer. The surface of the metal layer facing away from the supporting substrate is provided with the active material layer. The metal layer includes a conductive main body and a first protrusion extending from the conductive main body along a first direction perpendicular to the thickness direction of the first current collector. The active material layer includes a first active material portion and a second active material portion. The second active material portion is disposed on the side surface of the conductive main body away from the supporting substrate, and the first active material portion is disposed on the side surface of the first protrusion facing away from the supporting substrate.

[0007] In the above technical solution, the first active material part can play a role in stabilizing and supporting the first protrusion, which can reduce the probability of the first protrusion flipping or deforming, making the structure of the first electrode sheet high, thereby reducing the probability of metal layer cracking failure affecting the metal layer's overcurrent performance, increasing the overcurrent area between the first protrusion and the active material layer, reducing the contact resistance, reducing the probability of local overheating of the battery cell, and helping to improve the reliability of the battery cell.

[0008] In some embodiments, the first active material portion and the second active material portion are adjacent to each other.

[0009] In the above technical solution, by setting the first active material part and the second active material part adjacent to each other, the structural stability of the first active material part can be improved, and the probability of folding and deformation at the connection between the first protrusion and the conductive body part can be reduced. The first active material part can play a role in stably supporting the connection between the first protrusion and the conductive body part, thereby further improving the stabilizing effect of the first active material part on the first protrusion.

[0010] In some embodiments, along the first direction, the height of the first active material portion is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0011] In the above technical solution, by setting the height dimension of the first active material part along the first direction to be greater than or equal to 0.5 mm and less than or equal to 2 mm, it can not only improve the stable support of the first active material part on the first protrusion, but also reduce the space occupied by the first protrusion in the battery cell, which is conducive to further improving the energy density of the battery cell.

[0012] In some embodiments, along the thickness direction of the first electrode, the thickness of the first active material portion is less than the thickness of the second active material portion.

[0013] In the above technical solution, by setting the thickness of the first active material part to be smaller than the thickness of the second active material part, it is beneficial to further enhance the structural stability and reliability of the battery cell and extend the cycle life of the battery cell.

[0014] In some embodiments, the thickness of the first active material portion gradually decreases from the direction from the second active material portion to the first active material portion.

[0015] In the above technical solution, by setting the thickness of the first active material portion to gradually decrease from the second active material portion to the first active material portion, the structural stability and reliability of the battery cell can be further enhanced, which is conducive to further extending the cycle life of the battery cell, further reducing the weight of the battery cell, and further increasing the energy density of the battery cell.

[0016] In some embodiments, the electrode assembly further includes a first conductive element connected to a first protrusion. Along a first direction, a first active material portion is located between a second active material portion and the first conductive element. The first conductive element has a first connecting portion located on the side of the first protrusion away from the support substrate. The first connecting portion is welded to the first protrusion to form a first solder mark. The first active material portion and the first solder mark are spaced apart along the first direction to form a first gap between the first active material portion and the first solder mark.

[0017] In the above technical solution, the electrode assembly further includes a first conductive element, which has a first connecting portion. The first connecting portion is welded to a first protrusion to achieve electrical connection between the first conductive element and the metal layer. The first connecting portion can be welded to the first protrusion to form a first solder mark. Current can flow between the first connecting portion and the first protrusion through the first solder mark, which helps improve the current flow capacity between them. By creating a first gap between the first active material portion and the first solder mark, the problem of incomplete soldering can be reduced, which helps improve the reliability of the connection between the first connecting portion and the first protrusion.

[0018] In some embodiments, the first electrode further includes a protective layer, at least a portion of which is located on the side of the first connection portion away from the first protrusion and fixed to the first connection portion, and the protective layer covers the first solder mark portion.

[0019] In the above technical solution, the protective layer can protect the first connection portion, which is beneficial for protecting the first conductive component. The protective layer can also isolate the first connection portion from other structural components. The protective layer covering the first solder mark reduces the risk of exposure of the first solder mark, lowers the risk of the first solder mark puncturing the separator, further improves the reliability of the connection between the first protrusion and the first connection portion, further reduces the risk of short circuits in the battery cell, and ultimately enhances the reliability of the battery cell.

[0020] In some embodiments, the first conductive element includes an extension connected to the first connection portion, the extension being located on the side of the first connection portion near the second active material portion, at least a portion of the extension being located within the first gap, and the extension being not welded to the first protrusion.

[0021] In the above technical solution, heat is generated during the welding process, and the first conductive component may deform. By providing an extension portion that is not welded to the first protrusion, space can be provided for the deformation of the first connection portion to a certain extent, reducing stress concentration caused by deformation. When the first connection portion cools and shrinks, the extension portion can adapt to the overall deformation trend of the first conductive component, thereby reducing the stress at the first solder joint, improving the stability and reliability of the first solder joint, and reducing the generation of defects such as cracks. Furthermore, the extension portion can extend so that at least part of the extension portion is located within the first gap, which can improve the structural strength of the first protrusion located at the first gap, reduce the probability of the metal layer at the first gap folding or deforming, and further improve the reliability of the battery cell.

[0022] In some embodiments, from the direction of the first conductive element to the first active material portion, the extension portion and the first active material portion are spaced apart to form a second gap between the extension portion and the first active material portion, the protective layer covers the extension portion, and at least a portion of the protective layer is located in the second gap and fixed to the first protrusion portion.

[0023] In the above technical solution, the protective layer covering the extension can improve the integrity of the first connecting part, the extension part and the first protrusion part, and reduce the probability of damage to the extension part. The protective layer can fill at least part of the second gap, thereby improving the structural strength of the first protrusion part located in the second gap, reducing the probability of the metal layer at the second gap folding or deforming, reducing the probability of metal layer cracking and failure affecting the current performance of the metal layer, and further improving the connection strength between the first connecting part and the first protrusion part. This can improve the structural strength and stability of the electrode assembly, enabling the electrode assembly to withstand certain external forces and vibrations without damage, which is more conducive to improving the reliability of the battery cell.

[0024] In some embodiments, the protective layer extends to the first active material portion to cover at least a portion of the first active material portion.

[0025] In the above technical solution, the protective layer can completely fill the gap between the first active material part and the first conductive element, which can further improve the structural strength of the first protrusion located at the second gap. The portion of the protective layer covering the first active material part is beneficial to improving the structural stability of the first active material part and further improving the reliability of the battery cell.

[0026] In some embodiments, the protective layer covers a portion of the first active material portion, and the protective layer is spaced apart from the second active material portion.

[0027] In the above technical solution, by setting the protective layer and the second active material part separately, the probability of the thickness of the second active material part increasing along the thickness direction of the first current collector can be reduced, thereby reducing the risk of internal short circuit in the battery cell and further improving the reliability of the battery cell.

[0028] In some embodiments, along the first direction, the height dimension of the protective layer covering the first active material portion is greater than 0 mm and less than or equal to 1 mm.

[0029] In the above technical solution, by setting a protective layer covering the first active material portion with a height dimension greater than 0 mm and less than or equal to 1 mm along the first direction, the protective layer can cover a portion of the first active material portion and prevent the protective layer from covering the second active material portion. This reduces the probability of deformation of the internal structure of the first electrode and internal short circuit of the battery cell caused by local thickening of the first electrode, which is beneficial to further improve the reliability of the battery cell and further extend the service life of the battery cell.

[0030] In some embodiments, the thickness dimension of the overlap between the protective layer and the first active material portion along the thickness direction of the first current collector is less than or equal to the thickness dimension of the second active material portion.

[0031] In the above technical solution, by setting the thickness dimension of the overlapping part of the protective layer and the first active material part along the thickness direction of the first current collector to be less than or equal to the thickness dimension of the second active material part, the risk of uneven tension of the first electrode sheet can be reduced when the first electrode sheet is processed by rolling. This can help improve the structural stability of the first active material part, make the internal structure of the battery cell more uniform, and help to better improve the stability, integrity and reliability of the battery cell.

[0032] In some embodiments, from the direction from the first conductive element to the first active material portion, the extension extends to the first active material portion to cover a portion of the first active material portion.

[0033] In the above technical solution, the extension covering the portion of the first active material portion can increase the contact area between the first conductive element and the first active material portion, increase the current flow area, improve the conductivity of the electrode assembly, and further improve the structural strength of the metal layer located in the gap between the first active material portion and the first conductive element. It can further reduce the probability of the metal layer located in the gap between the first active material portion and the first conductive element folding or deforming, which is beneficial to further improve the structural stability of the first active material portion and further improve the reliability of the battery cell.

[0034] In some embodiments, along the first direction, the height dimension of the extension covering the first active material portion is greater than 0 mm and less than or equal to 0 mm.

[0035] In the above technical solution, by setting the extension portion to cover the first active material portion with a height dimension greater than 0 mm and less than or equal to 1 mm along the first direction, the extension portion can cover a portion of the first active material portion and prevent the extension portion from covering the second active material portion. This reduces the probability of deformation of the internal structure of the first electrode and internal short circuit of the battery cell caused by local thickening of the first electrode, which is beneficial to further improve the reliability of the battery cell and further extend the service life of the battery cell.

[0036] In some embodiments, the thickness dimension of the overlap between the extension and the first active material portion along the thickness direction of the first current collector is less than or equal to the thickness dimension of the second active material portion.

[0037] In the above technical solution, by setting the thickness dimension of the overlapping part of the extension and the first active material part along the thickness direction of the first current collector to be less than or equal to the thickness dimension of the second active material part, the probability of uneven tension in the first electrode can be reduced, thereby reducing the risks of decreased conductivity, reduced charge and discharge efficiency, and impact on the overall performance of the battery cell. Furthermore, the first electrode can maintain good structural stability and lithium-ion transport performance during lithium intercalation, minimizing lithium-ion loss and thus slowing down the rate of battery capacity decline. This is more conducive to giving the battery cell better charge and discharge performance and a longer service life.

[0038] In some embodiments, along the first direction, the height dimension of the first solder mark is greater than or equal to 1.5 mm and less than or equal to 3 mm.

[0039] In the above technical solution, by setting the height dimension of the first solder mark part along the first direction to be greater than or equal to 1.5 mm and less than or equal to 3 mm, the current flow capacity between the connecting part and the first protrusion part can be further enhanced, the space occupied by the first conductive part can be reduced, and the energy density of the battery cell can be further improved.

[0040] In some embodiments, along the first direction, the distance between the first solder mark portion and the first active material portion is greater than or equal to 0.1 mm and less than or equal to 1 mm.

[0041] In the above technical solution, by setting the interval between the first solder mark and the first active material part along the first direction to be greater than or equal to 0.1 mm and less than or equal to 1 mm, the probability of incomplete soldering during welding can be reduced, and the reliability of the first electrode can be improved.

[0042] In some embodiments, there are two metal layers and two active material layers. Along the thickness direction of the first current collector, the two metal layers are respectively disposed on opposite sides of the support substrate, and the two active material layers are respectively disposed on the side of the two metal layers away from the support substrate. A first conductive element is provided on both sides of the first current collector. The first conductive elements on both sides of the first current collector are disposed opposite to each other, and the first conductive elements are connected to the metal layer on the corresponding side.

[0043] In the above technical solution, by setting two metal layers and two active material layers, the two active material layers can increase the contact area between the first current collector and the electrolyte, which is beneficial to improving the charge and discharge capacity of the battery cell. Simultaneously, the two metal layers can better collect and conduct electrons, improving the battery's charge and discharge efficiency and reducing energy loss. Furthermore, the first current collector can be connected to multiple first conductive components, further enhancing the overcurrent performance of the battery cell.

[0044] In some embodiments, along a first direction, the first conductive element includes a first connecting portion and a second connecting portion, the first connecting portion and the second connecting portion are connected together, the second connecting portion protrudes from the first active material portion in the direction to the first conductive element from the first protrusion portion, the two second connecting portions are welded to form a second solder mark portion, and a protective layer covers at least a portion of the second solder mark portion.

[0045] In the above technical solution, the first conductive element may include a first connecting portion and a second connecting portion, which are connected together. First conductive elements are provided on both sides of the first current collector, and both first conductive elements are connected to the metal layer on their respective sides. The second connecting portions of the two first conductive elements are welded together, which can effectively improve the conductivity of the first electrode, further improve the fast-charging performance of the battery cell, and further improve the reliability of the battery cell. Furthermore, the protective layer covers at least a portion of the second solder mark, which can reduce the risk of the second solder mark being exposed, reduce the risk of the second solder mark puncturing the separator, and further improve the reliability of the battery cell.

[0046] In some embodiments, the second solder mark and the first solder mark are adjacent to each other along the first direction.

[0047] In the above technical solution, the second solder mark and the first solder mark are adjacent, which can improve the integrity of the second solder mark and the first solder mark, and improve the processing efficiency of welding the two first conductive parts.

[0048] In some embodiments, along the first direction, the height dimension of the second solder mark is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0049] In the above technical solution, by setting the height dimension of the second solder mark part along the first direction to be greater than or equal to 0.5 mm and less than or equal to 2 mm, the current carrying capacity of the two first conductive parts can be further enhanced, the space occupied by the first conductive parts can be reduced, and the energy density of the battery cell can be further improved.

[0050] In some embodiments, the protective layer completely covers the second solder mark.

[0051] In the above technical solution, by setting a protective layer to completely cover the second solder mark, the risk of exposure of the second solder mark can be further reduced, which is conducive to further improving the reliability of the battery cell. Furthermore, by setting the distance from the edge of the protective layer to the edge of the second solder mark in the direction from the first active material part to the first conductive part to be greater than 0 mm and less than or equal to 0.5 mm, the edge of the protective layer can be made to extend beyond the edge of the second solder mark, and the height dimension of the protective layer along the first direction can be reasonable, which can further reduce material waste.

[0052] In some embodiments, the electrode assembly further includes a second electrode and a diaphragm, with the first and second electrodes disposed opposite to each other and the diaphragm located between the first and second electrodes. The second electrode includes a second current collector, a second active material layer, and an insulating layer. The second current collector includes a current collector body and a second protrusion extending from the current collector body along a first direction. Along the thickness direction of the second current collector, the second active material layer and the insulating layer are provided on both surfaces of the current collector body. The second active material layer and the insulating layer located on the same surface of the current collector body are arranged along the first direction, and the second active material layer is located on the side of the insulating layer opposite to the second protrusion.

[0053] In the above technical solution, by setting a second electrode and a separator, the first electrode, the second electrode and the separator can work together to achieve the charging and discharging effect of the battery cell, which is conducive to further improving the reliability of the battery cell.

[0054] In some embodiments, along a first direction, the insulating layer includes a first edge and a second edge, the first edge being further away from the second active material layer than the second edge, and the first conductive element includes a third edge close to the second active material portion, the third edge extending beyond the first edge but not beyond the second edge along the direction from the first conductive element to the second active material portion.

[0055] In the above technical solution, by reasonably setting the relative positions of the insulating layer and the first conductive element, the probability of the second electrode contacting the first electrode can be reduced, which is conducive to further reducing the risk of short circuit in the battery cell and further improving the reliability of the battery cell.

[0056] In some embodiments, along a first direction, the end of the first active material portion that is away from the second active material portion extends beyond the second active material layer.

[0057] In the above technical solution, by setting the end of the first active material portion that is away from the second active material portion along the first direction to extend beyond the second active material layer, the first active material portion can provide more space for the volume change of the active material, which can further improve the stability of the battery cell, reduce the possibility of safety problems such as thermal runaway of the battery cell, and is more conducive to improving the reliability of the battery cell.

[0058] In some embodiments, the compaction density of the first active material portion is greater than or equal to 1.3 g / cm³. 3 And less than or equal to 1.8 g / cm³ 3 .

[0059] In the above technical solution, the compaction density of the first active material portion is set to be greater than or equal to 1.3 g / cm³. 3 And less than or equal to 1.8 g / cm³ 3This not only enables the first active material part to support the first protrusion, but also stabilizes the structure of the first current collector and reduces the probability of cracking of the first electrode.

[0060] In some embodiments, the binder content of the first active material portion is greater than or equal to 1% and less than or equal to 5%.

[0061] In the above technical solution, by setting the binder content of the first active material part to be greater than or equal to 1% and less than or equal to 5%, the hardness of the first active material part can be improved, the first active material part can support the first protrusion, and the conductive network inside the first active material part can be made reasonable, which is conducive to improving the dynamic performance of the battery cell.

[0062] In some embodiments, the support substrate is constructed as an insulating substrate.

[0063] In the above technical solution, by setting the support substrate to be an insulating substrate, the first current collector can be a composite current collector, which can reduce the weight of the battery cell, reduce the risk of short circuit in the battery cell, and reduce the self-discharge phenomenon of the battery cell. This is beneficial to maintaining the charge of the battery cell, further extending the storage time and service life of the battery cell, and enabling the battery cell to better maintain its performance when stored for a long time or not used.

[0064] Secondly, embodiments of this application also provide a battery device, including the battery cell described in the above embodiments.

[0065] Thirdly, embodiments of this application also provide an electrical device, including the battery device described in the above embodiments.

[0066] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0067] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0068] Figure 1 Schematic diagram of an electrical device provided for some embodiments of this application;

[0069] Figure 2 Schematic diagram of a battery device provided for some embodiments of this application;

[0070] Figure 3 Exploded views of a single battery cell provided in some embodiments of this application;

[0071] Figure 4This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0072] Figure 5 A front view of a first electrode provided for some embodiments of this application;

[0073] Figure 6 A side sectional view of a first electrode provided for some embodiments of this application;

[0074] Figure 7 A side sectional view of the first electrode provided for other embodiments of this application;

[0075] Figure 8 A side sectional view of the first electrode provided for other embodiments of this application;

[0076] Figure 9 A side sectional view of a first electrode provided for other embodiments of this application.

[0077] Figure label:

[0078] Electrical appliance 100,

[0079] Battery assembly 110, housing 1101, first housing section 11011, second housing section 11012, assembly space 11013.

[0080] Battery cell 1,

[0081] 10. Outer shell, 11. End cap, 12. Shell body, 13. Installation space.

[0082] Electrode assembly 20,

[0083] First electrode 30, active material layer 31, first active material portion 311, second active material portion 312, first current collector 32, supporting substrate 321, metal layer 322, conductive main body portion 3221, first protrusion 3222, second gap 33.

[0084] First conductive element 40, extension 41, bending structure 411, second connecting part 42, third edge 43.

[0085] Second electrode 50, second current collector 51, current collector body 511, second active material layer 52, insulating layer 53, first edge 531, second edge 532.

[0086] Diaphragm 60,

[0087] Protective layer 70,

[0088] Electrode terminal 80,

[0089] First solder mark 91, second solder mark 92

[0090] Controller 120, motor 130. Detailed Implementation

[0091] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0092] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0093] 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 description 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 description, claims and foregoing drawings of this application are intended to cover non-exclusive inclusion.

[0094] 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.

[0095] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0096] 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.

[0097] In this application, "multiple" refers to two or more.

[0098] In this application, the battery cell can be a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., and the embodiments of this application are not limited in this regard. The battery cell can be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited in this regard either. Battery cells are generally divided into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited in this regard either.

[0099] A single battery cell may include a casing, electrode components, and electrolyte. The casing houses the electrode components and electrolyte. The electrode components consist of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode components. The positive electrode may include 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 uncoated positive current collector protrudes beyond the coated positive current collector, serving as the positive electrode tab. 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 uncoated negative current collector protrudes beyond the coated negative current collector, serving as the negative electrode tab. In order to achieve the effect of passing large currents without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together.

[0100] The positive electrode current collector can be made of carbon, metal foil, or a composite current collector. For example, if the positive electrode current collector is a metal foil, it can be made of stainless steel, copper, aluminum, nickel, carbon electrode, nickel, titanium, silver-treated aluminum, or stainless steel. For example, if the positive electrode current collector is a composite current collector, it can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0101] The positive electrode active material layer includes a positive electrode active material, which may include at least one of the following: lithium phosphates, lithium transition metal oxides, and their respective modified compounds. Other conventional materials that can be used as positive electrode active material layers in battery cells may also be used as positive electrode active materials. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co0.25Mn0.25O2 (also abbreviated as NCM211), LiNi0.6Co0.2Mn0.2O2 (also abbreviated as NCM622), LiNi0.8Co0.1Mn0.1O2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.80Co0.15Al0.05O2) and their modified compounds.

[0102] The negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, if the negative electrode current collector is a metal foil, it can be made of silver-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrodes, nickel, or titanium. For example, if the negative electrode current collector is a foamed metal, it can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, or foamed carbon. For example, if the negative electrode current collector is a composite current collector, it can include a polymer material substrate and a metal layer. Composite current collectors can be formed by forming metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0103] The negative electrode active material layer includes a negative electrode active material, which can be a negative electrode active material known in the art for use in battery cells. The negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials can include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials can include at least one of elemental tin, tin oxide compounds, and tin alloys. The negative electrode active material of this application can also use other conventional materials that can be used as negative electrode active materials in battery cells. These negative electrode active materials can be used alone or in combination of two or more.

[0104] In some embodiments, the positive current collector can be aluminum foil, and the negative current collector can be a composite current collector. In other embodiments, both the positive and negative current collectors can be composite current collectors.

[0105] The separator can be made of PP (polypropylene) or PE (polyethylene), and can be a single-layer film or a multi-layer composite film. Furthermore, the electrode assembly can be a wound structure or a stacked structure; the embodiments of this application are not limited to these. As an example, the electrode assembly can be a wound structure, where the positive electrode, negative electrode, and separator can be wound into a wound structure. As another example, the electrode assembly can be a stacked structure, where there can be multiple positive and negative electrode sheets, and the multiple positive and multiple negative electrode sheets can be alternately stacked.

[0106] In recent years, with the continuous development of new energy vehicles, battery devices, as the power source of electric vehicles, play an irreplaceable and crucial role. A battery device comprises multiple battery cells, and as a core component of new energy vehicles, it places high demands on the reliability of both the battery device and its individual cells.

[0107] In related technologies, the first protrusion of the first electrode is prone to folding and deformation, and the metal layer located at the first protrusion is prone to cracking, thereby affecting the overcurrent performance within the battery cell and the reliability of the battery cell.

[0108] Based on the above considerations, in order to improve the reliability of the battery cell, a battery cell was designed after in-depth research, including: a shell and an electrode assembly. The shell is provided with electrode terminals, and the electrode assembly is disposed inside the shell. The electrode assembly includes a first electrode plate, which includes a first current collector and an active material layer. The first current collector includes a supporting substrate and a metal layer. The supporting substrate, the metal layer, and the active material layer are stacked along the thickness direction of the first current collector. The metal layer is at least partially located between the supporting substrate and the active material layer. The surface of the metal layer facing away from the supporting substrate is provided with the active material layer. The metal layer includes a conductive main body and a first protrusion extending from the conductive main body along a first direction perpendicular to the thickness direction of the first current collector. The active material layer includes a first active material part and a second active material part. The second active material part is disposed on the side surface of the conductive main body away from the supporting substrate, and the first active material part is disposed on the side surface of the first protrusion facing away from the supporting substrate.

[0109] According to the battery cell of this application, the first active material portion can stably support the first protrusion, which can reduce the probability of the first protrusion folding or deforming, making the structure of the first electrode sheet high, thereby reducing the probability of metal layer cracking failure affecting the current performance of the metal layer, increasing the current area between the first protrusion and the active material layer, reducing the contact resistance, reducing the probability of local overheating of the battery cell, and improving the reliability of the battery cell.

[0110] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. Any electrical device that can be connected to the battery device disclosed in this application is also an applicable electrical device, which helps to broaden the applicability of the battery device.

[0111] This application provides an electrical device that uses a battery 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. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0112] For ease of explanation, the following embodiments use a vehicle as an example of an electrical device 100 according to some embodiments of this application.

[0113] like Figure 1 As shown, Figure 1This is a schematic diagram of an electrical device 100 provided in some embodiments of this application. The electrical device 100 can be a vehicle, which can be a new energy vehicle, such as a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle. A battery device 110 can be installed inside the vehicle, and the battery device 110 can be located at the bottom, front, or rear of the vehicle. The battery device 110 can be used to supply power to the vehicle; for example, the battery device 110 can serve as the vehicle's operating power source or its main power source. The vehicle may also include a controller 120 and a motor 130. The controller 120 controls the battery device 110 to supply power to the motor 130. The battery device 110 is used to meet the power needs of the vehicle during starting, navigation, and driving. The battery device 110 is connected to the vehicle to realize its application within the vehicle.

[0114] like Figure 2 As shown, Figure 2 This is a schematic diagram of a battery device 110 provided in some embodiments of this application. The battery device 110 includes a plurality of battery cells 1 and a housing 1101, with the battery cells 1 installed inside the housing 1101. The housing 1101 forms an assembly space 11013, within which the battery cells 1 are assembled. The housing 1101 can have various shapes, such as a cylinder or a cuboid. The housing 1101 may include a first housing portion 11011 and a second housing portion 11012. The first housing portion 11011 and the second housing portion 11012 are fastened together, forming a closed space inside the housing 1101 for assembling the battery cells 1. Here, "closed" refers to covering or shutting off; it can be sealed or unsealed.

[0115] This application uses a vehicle as an example to illustrate that the electrical device 100 can be part of the vehicle's chassis structure. For example, a portion of the housing 1101 can be at least a part of the vehicle's floor, or a portion of the housing 1101 can be at least a part of the vehicle's crossbeams and longitudinal beams.

[0116] like Figure 3 As shown, Figure 3 The following is an exploded view of a battery cell 1 provided in some embodiments of this application. The battery cell 1 may include a housing 10 and an electrode assembly 20. The electrode assembly 20 is installed inside the housing 10. The housing 10 may be of various shapes, such as a cylinder, a cuboid, etc.

[0117] In the battery device 110, multiple battery cells 1 can be connected in series, in parallel, or in a mixed connection. A mixed connection means that multiple battery cells 1 are connected in both series and parallel. Multiple battery cells 1 can be directly connected in series, in parallel, or in a mixed connection, and then the entire assembly of the multiple battery cells 1 is housed within the housing 1101. Alternatively, the battery device 110 can also consist of multiple battery cells 1 first connected in series, in parallel, or in a mixed connection to form a battery module, and then multiple battery modules connected in series, in parallel, or in a mixed connection to form a whole, which is also housed within the housing 1101. The battery device 110 may also include other structures; for example, the battery device 110 may also include a busbar component, which can be used to realize the electrical connection between multiple battery cells 1.

[0118] Each battery cell 1 can be a secondary battery or a primary battery. A secondary battery refers to a battery cell 1 that can be recharged after discharge to activate its active materials and continue to be used. The battery cell 1 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application is not limited to any of these. The battery cell 1 can be cylindrical, flat, cuboid, or other shapes.

[0119] According to some embodiments of this application, such as Figures 3-6 As shown, the battery cell 1 may include: a housing 10 and an electrode assembly 20. The housing 10 is provided with electrode terminals 80. The electrode assembly 20 is disposed within the housing 10 and includes a first electrode 30. The first electrode 30 includes a first current collector 32 and an active material layer 31. The first current collector 32 includes a supporting substrate 321 and a metal layer 322. The supporting substrate 321, the metal layer 322, and the active material layer 31 are stacked along the thickness direction of the first current collector 32. The metal layer 322 is at least partially located between the supporting substrate 321 and the active material layer 31, and the metal layer 322 faces away from the supporting substrate 321. The surface of the support substrate 321 is provided with an active material layer 31, wherein the metal layer 322 includes a conductive main body portion 3221 and a first protrusion portion 3222 extending from the conductive main body portion 3221 along a first direction, the first direction being perpendicular to the thickness direction of the first current collector 32. The active material layer 31 includes a first active material portion 311 and a second active material portion 312. The second active material portion 312 is disposed on the side surface of the conductive main body portion 3221 away from the support substrate 321, and the first active material portion 311 is disposed on the side surface of the first protrusion portion 3222 opposite to the support substrate 321.

[0120] Among them, such as Figure 3As shown, the battery cell 1 may include a housing 10 and an electrode assembly 20 disposed within the housing 10. The housing 10 may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing, or an aluminum-plastic film, etc. The housing 10 may include an end cap 11 and a housing body 12, which together define an installation space 13. When the battery cell 1 is placed vertically, the end cap 11 may be disposed at at least one end of the housing 10 along the height direction of the battery cell 1. When the battery cell 1 is placed vertically... Figure 3 When setting the orientation, the height direction of battery cell 1 is as follows: Figure 3 In the Z direction. As an example, the housing 10 may include a housing body 12 and an end cap 11. The end cap 11 may be located above the housing body 12, and the housing body 12 may be assembled with the end cap 11. The housing body 12 and the end cap 11 together define an installation space 13. The housing 10 is provided with electrode terminals 80, which may be provided on the end cap 11. The electrode assembly 20 is provided inside the housing 10 and may be installed in the installation space 13. There may be two electrode terminals 80, and both electrode terminals 80 may be connected to the electrode assembly 20 of the battery cell 1.

[0121] The electrode assembly 20 may include a first electrode 30. In this embodiment, the first electrode 30 is described as a negative electrode. The first electrode 30 may include a first current collector 32 and an active material layer 31. The first current collector 32 may include a supporting substrate 321 and a metal layer 322. The supporting substrate 321 may be conductive or insulating. The supporting substrate 321 may be a metal, a polymer material, etc. The metal layer 322 has good conductivity and can be used for current carrying.

[0122] The active material layer 31 may include a first active material portion 311 and a second active material portion 312. Both the second active material portion 312 and the first active material portion 311 can be in direct contact with the electrolyte in the battery cell 1. Both the second active material portion 312 and the first active material portion 311 can conduct ions and electrons, and both can store and release electrical energy. During charging, the active material converts electrical energy into chemical energy through a chemical reaction and stores it. During discharging, this stored chemical energy is converted back into electrical energy through the opposite chemical reaction and released.

[0123] Along the thickness direction of the first current collector 32, the supporting substrate 321, the metal layer 322, and the active material layer 31 can be stacked. When the first current collector 32 is as follows... Figure 6 When setting the direction, the thickness direction of the first current collector 32 can be... Figure 6In the Y-direction, the thickness direction of the first current collector 32 can be perpendicular to the height direction of the battery cell 1. A metal layer 322 is provided on at least one side of the support substrate 321 along the thickness direction of the first current collector 32. The metal layer 322 can be located between the support substrate 321 and the corresponding active material layer 31. This embodiment uses the example of the support substrate 321 having metal layers 322 on both sides along the thickness direction of the first current collector 32. An active material layer 31 is provided on the surface of the metal layer 322 away from the support substrate 321. The active material layer 31 can be coated on the surface of the metal layer 322. The metal layer 322 provides physical support for the active material layer 31, allowing the active material of the active material layer 31 to adhere uniformly to the surface of the metal layer 322. This ensures that the active material layer 31 maintains a stable structure and morphology during the charging and discharging process of the battery cell 1, reducing the probability of the active material layer 31 detaching or deforming, thereby extending the service life of the battery cell 1.

[0124] The metal layer 322 may include a conductive main body portion 3221 and a first protrusion 3222, which may be arranged along a first direction, such as... Figure 6 As shown, the first protrusion 3222 can be located above the conductive body portion 3221. The first protrusion 3222 can extend from the conductive body portion 3221 along a first direction. When the first current collector 32... Figure 6 When setting the direction, the first direction is parallel to the height direction of the battery cell 1 and perpendicular to the thickness direction of the first current collector 32.

[0125] The active material layer 31 may include a first active material portion 311 and a second active material portion 312. Both the second active material portion 312 and the first active material portion 311 can be coated on the surface of the metal layer 322. The conductive main body portion 3221 has the second active material portion 312 on its surface opposite to the supporting substrate 321. The conductive main body portion 3221 supports the second active material portion 312, and the second active material portion 312 protects the conductive main body portion 3221, thus improving its structural stability. Furthermore, the conductive main body portion 3221 has good conductivity. The second active material portion 312 is coated on the surface of the conductive main body portion 3221, allowing for close contact. This facilitates the rapid transfer of electrons generated by the oxidation-reduction reaction of the active material during the charging and discharging process of the battery cell 1 through the conductive main body portion 3221, enabling normal charging and discharging of the battery cell 1.

[0126] Along the thickness direction of the first current collector 32, a first active material portion 311 may be provided on the surface of the first protrusion 3222 facing away from the supporting substrate 321. The first active material portion 311 may be fixed to at least a portion of the first protrusion 3222. Further, at least a portion of the first protrusion 3222 may be stacked with the first active material portion 311 along the thickness direction of the first current collector 32. The first active material portion 311 may be coated on a portion of the surface of the first protrusion 3222, thereby improving the structural stability of the corresponding first protrusion 3222. The first active material portion 311 and the second active material portion 312 may be arranged along a first direction.

[0127] In the prior art, the first protrusion 3222 of the first electrode 30 is prone to folding and deformation, and the metal layer 322 located at the position of the first protrusion 3222 is prone to cracking, thereby affecting the overcurrent performance in the battery cell 1 and the reliability of the battery cell 1.

[0128] The first active material portion 311 can be coated on a portion of the surface of the first protrusion 3222. The first active material portion 311 can improve the structural stability of the corresponding first protrusion 3222 and effectively reduce the risk of the metal layer 322 at the first protrusion 3222 cracking. Furthermore, by providing the first active material portion 311, the current-carrying area between the first protrusion 3222 and the active material layer 31 can be increased, reducing current concentration and the resistance encountered during current flow, thus reducing contact resistance. The first active material portion 311 enables smoother and more uniform current conduction from the active material layer 31 to the electrode terminal 80, reducing the probability of current concentration at the first protrusion 3222. By providing the first active material portion 311, the resistance difference between the first protrusion 3222 and the active material layer 31 can be reduced, reducing the risk of uneven current distribution and excessively high local current density. This effectively reduces the probability of local overheating of the battery cell 1 due to excessively high local current density, which is beneficial to improving the reliability and stability of the battery cell 1 and extending its service life.

[0129] By providing a first active material portion 311, this application can effectively reduce the risk of metal layer 322 cracking at the first protrusion 3222 caused by vibration and bending, which is beneficial to enhancing the structural stability of the first protrusion 3222, increasing the flow area between the first protrusion 3222 and the active material layer 31, reducing the contact resistance, reducing the probability of local overheating of the battery cell 1, and providing additional lithium-ion storage sites for the battery cell 1, which is beneficial to reducing the probability of lithium plating at the edge of the active material layer 31.

[0130] like Figure 5As shown, along the length direction of the first electrode 30, the length of the first active material portion 311 can be equal to the length of the first protrusion 3222. When the first electrode 30 is as shown... Figure 5 When setting the direction, the length direction of the first electrode 30 is... Figure 5 In the X direction, the length direction of the first electrode 30 is perpendicular to the first direction, and the length direction of the first electrode 30 is perpendicular to the thickness direction of the first current collector 32. The first active material portion 311 can stably support the first protrusion 3222, which can reduce the risk of the first protrusion 3222 flipping or deforming, thereby reducing the risk of the metal layer 322 cracking and failing, which would affect the overcurrent performance of the metal layer 322, and is conducive to improving the reliability of the battery cell 1.

[0131] In the above technical solution, the first active material part 311 can play a role in stabilizing and supporting the first protrusion 3222, which can reduce the probability of the first protrusion 3222 folding or deforming, making the structure of the first electrode 30 high, thereby reducing the probability of the metal layer 322 cracking and failing, which would affect the current performance of the metal layer 322. It can increase the current area between the first protrusion 3222 and the active material layer 31, reduce the contact resistance, reduce the probability of local overheating of the battery cell 1, and help improve the reliability of the battery cell 1.

[0132] According to some embodiments of this application, the support substrate 321 may be conductive or insulating. As an example, the support substrate 321 may be conductive, and the first current collector 32 may be made of a metallic material. A conductive support substrate 321 provides a good transport channel for electrons, which is beneficial for improving electron transport efficiency. This allows electrons in the battery cell 1 to be transported more quickly and efficiently between the first current collector 32 and the active material layer 31 during charging and discharging, helping to reduce obstacles in current transport and improving the charging and discharging efficiency of the battery cell 1. It can also enhance the current collection effect of the first current collector 32, enabling it to better collect and conduct current, resulting in a more uniform current distribution on the first current collector 32. This helps reduce situations where the local current density is too high or too low, allowing the active material layer 31 to participate more fully and uniformly in the electrochemical reaction, thereby improving the overall performance of the battery cell 1.

[0133] As another example, the support substrate 321 can be insulating. An insulating support substrate 321 effectively isolates the first current collector 32 from other conductive components. The insulating support substrate 321 reduces the risk of short circuits in the battery cell 1, minimizing the occurrence of short circuits due to accidental contact during assembly or use. It also reduces self-discharge in the battery cell 1, decreasing the probability of disordered electron conduction in the non-charging / discharging state. This helps maintain the charge of the battery cell 1, extending its storage time and lifespan, and allowing the battery cell 1 to better maintain its performance during long-term storage or when not in use.

[0134] The first current collector 32 can be a composite current collector, which can be constructed as a composite structure of a supporting substrate 321 and a metal layer 322. The metal layer 322 has a small thickness, and the supporting substrate 321 can be made of lightweight materials, such as polymer films. Compared with a current collector constructed of pure metal, the amount of metal used in the first current collector 32 can be reduced, which is beneficial to reducing the weight of the first electrode 30, thereby reducing the weight of the battery cell 1 and increasing the energy density of the battery cell 1. Furthermore, in the event of puncture of the first current collector 32, the probability of the metal layer 322 overlapping with other components can be reduced, which can further reduce the short-circuit risk of the battery cell 1 and further improve the reliability of the battery cell 1.

[0135] According to some embodiments of this application, such as Figure 6 As shown, the first active material portion 311 and the second active material portion 312 are adjacent to each other.

[0136] The first active material portion 311 and the second active material portion 312 are arranged along a first direction, adjacent to each other. The conductive body portion 3221 is provided with the second active material portion 312. The first active material portion 311 is located in part of the structure of the first protrusion 3222. The first active material portion 311 and the second active material portion 312 can form a continuous and stable active material layer 31. Figure 6As shown, along the first direction, the second active material portion 312 can be located below the first active material portion 311. The second active material portion 312 can support the first active material portion 311, which helps to improve the structural stability of the first active material portion 311, thereby further improving the supporting effect of the first active material portion 311 on the first protrusion 3222. Furthermore, the second active material portion 312 is disposed on the conductive body portion 3221, and the first active material portion 311 is disposed on the first protrusion 3222. The first active material portion 311 and the second active material portion 312 are adjacent to each other, which can reduce the probability of folding or deformation at the connection between the first protrusion 3222 and the conductive body portion 3221. The first active material portion 311 can stably support the connection between the first protrusion 3222 and the conductive body portion 3221.

[0137] In the above technical solution, by setting the first active material part 311 and the second active material part 312 adjacent to each other, the structural stability of the first active material part 311 can be improved, and the probability of folding and deformation at the connection between the first protrusion 3222 and the conductive body part 3221 can be reduced. The first active material part 311 can play a role in stably supporting the connection between the first protrusion 3222 and the conductive body part 3221, thereby further improving the stabilizing effect of the first active material part 311 on the first protrusion 3222.

[0138] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the height of the first active material portion 311 is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0139] Among them, such as Figure 6As shown, along the first direction, the height of the first active material portion 311 can be H1, satisfying the relationship: 0.5mm ≤ H1 ≤ 2mm. For example, the height of the first active material portion 311 can be 0.5mm, 0.9mm, 1.2mm, 1.7mm, 2mm, etc. The height of the first active material portion 311 can be within the range of 0.5mm to 2mm, including any value including the endpoint values; any value is an optional height of the first active material portion 311 in this application. If the height of the first active material portion 311 is less than 0.5mm, it will affect the stable support of the first active material portion 311 for the first protrusion 3222. If the height of the first active material portion 311 is greater than 2mm, it will increase the space occupied by the first protrusion 3222 within the battery cell 1, affecting the energy density of the battery cell 1. Therefore, the height of the first active material portion 311 is between 0.5 mm and 2 mm, which can improve the stable support of the first active material portion 311 for the first protrusion 3222 and reduce the space occupied by the first protrusion 3222 in the battery cell 1, which is conducive to further improving the energy density of the battery cell 1.

[0140] In the above technical solution, by setting the height dimension of the first active material part 311 along the first direction to be greater than or equal to 0.5 mm and less than or equal to 2 mm, it can not only improve the stable support of the first active material part 311 on the first protrusion 3222, but also reduce the space occupied by the first protrusion 3222 in the battery cell 1, which is conducive to further improving the energy density of the battery cell 1.

[0141] According to some embodiments of this application, the components of the first active material portion 311 and the second active material portion 312 may be the same, or the components of the first active material portion 311 and the second active material portion 312 may be different.

[0142] In this process, both the first active material portion 311 and the second active material portion 312 can be coated onto the metal layer 322, and both the first active material portion 311 and the second active material portion 312 are fixed to the metal layer 322. When coating the active material layer 31, the first active material portion 311 and the second active material portion 312 can use the same active material, making the first active material portion 311 and the second active material portion 312 constructed as an active material layer 31 with the same composition. This allows the coating process to be completed in one step, which is beneficial for improving the production efficiency of the battery cell 1. After the battery cell 1 is used, the composition of the first active material portion 311 and the second active material portion 312 can change, and the compositions of the first active material portion 311 and the second active material portion 312 can be different.

[0143] In the above technical solution, when coating the active material layer 31, the first active material portion 311 and the second active material portion 312 can use the same active material, thereby completing the coating process in one step. This is beneficial for improving the production efficiency of the battery cell 1 and also for improving the stability of the battery cell 1. After the battery cell 1 is used, the composition of the first active material portion 311 and the second active material portion 312 can change, and the composition of the first active material portion 311 and the second active material portion 312 can be different.

[0144] In some embodiments, along the thickness direction of the first electrode 30, the thickness of the first active material portion 311 is less than the thickness of the second active material portion 312.

[0145] In this case, along the thickness direction of the first electrode 30 (i.e., along the thickness direction of the first current collector 32), the thickness of the first active material portion 311 can be smaller than the thickness of the second active material portion 312. This can reduce problems such as cracking and detachment of the first active material portion 311, and reduce problems such as internal short circuits caused by powder shedding from the edges of the first active material portion 311. This is beneficial to further enhance the structural stability and reliability of the battery cell 1 and to extend the cycle life of the battery cell 1.

[0146] In the above technical solution, by setting the thickness of the first active material part 311 to be smaller than the thickness of the second active material part 312, it is beneficial to further enhance the structural stability and reliability of the battery cell 1 and to extend the cycle life of the battery cell 1.

[0147] According to some embodiments of this application, such as Figure 6 As shown, the thickness of the first active material portion 311 gradually decreases from the second active material portion 312 to the first active material portion 311.

[0148] Along the first direction, from the second active material portion 312 to the first active material portion 311, the thickness of the first active material portion 311 gradually decreases, and its longitudinal cross-section can be constructed as a trapezoid or semi-circle, etc. During the charging and discharging process of the battery cell 1, the volume of the active material changes, thereby generating stress. The gradually decreasing thickness of the first active material portion 311 can better adapt to this volume change and can alleviate stress concentration to a certain extent. Compared with a first active material portion 311 of uniform thickness, the gradually decreasing thickness of the first active material portion 311 can disperse stress through deformation at different locations, further reducing problems such as cracking and detachment of the first active material portion 311 caused by stress concentration, which is beneficial to further improving the cycle life of the battery cell 1. When the battery cell 1 is subjected to external pressure or vibration, the gradually decreasing thickness of the first active material portion 311 can also more effectively absorb and disperse external forces, reducing the risk of damage to the first protrusion 3222, and further enhancing the structural stability and reliability of the battery cell 1.

[0149] The portion of the first active material portion 311 furthest from the second active material portion 312 has the smallest thickness, while the portion closest to the second active material portion 312 has the largest thickness. This saves material and helps reduce the production cost of the battery cell 1. Due to the reduced material usage, the weight of the battery cell 1 is further reduced, which helps to further improve the energy density of the battery cell 1.

[0150] In the above technical solution, by setting the thickness of the first active material part 311 to gradually decrease from the second active material part 312 to the first active material part 311, the structural stability and reliability of the battery cell 1 can be further enhanced, which is conducive to further extending the cycle life of the battery cell 1, further reducing the weight of the battery cell 1, and further increasing the energy density of the battery cell 1.

[0151] According to some embodiments of this application, such as Figure 6 As shown, the electrode assembly 20 also includes a first conductive element 40, which is connected to a first protrusion 3222. Along the first direction, a first active material portion 311 is located between a second active material portion 312 and the first conductive element 40. The first conductive element 40 has a first connecting portion located on the side of the first protrusion 3222 away from the support substrate 321. The first connecting portion is welded to the first protrusion 3222 to form a first solder mark portion 91. The first active material portion 311 and the first solder mark portion 91 are spaced apart along the first direction to form a first gap between the first active material portion 311 and the first solder mark portion 91.

[0152] The electrode assembly 20 may further include a first conductive element 40, which can be electrically connected to the electrode terminal 80. As an example, the first conductive element 40 can be directly welded to the electrode terminal 80, thus facilitating the connection operation and manufacturing. As another example, the first conductive element 40 can be connected to the electrode terminal 80 via a conductive element (e.g., an electrical adapter). Along the thickness direction of the first current collector 32, at least a portion of the first conductive element 40 can be located on the side of the first protrusion 3222 opposite to the support base 321, and the first conductive element 40 can be connected to the first protrusion 3222. The first conductive element 40 can connect the first protrusion 3222 and the electrode terminal 80. As an example, the material of the first conductive element 40 can be the same as the material of the first protrusion 3222.

[0153] The first active material portion 311 and the second active material portion 312 can be arranged along a first direction. Along this first direction, the first conductive element 40 can be disposed opposite to the active material layer 31. The first conductive element 40, the first active material portion 311, and the second active material portion 312 can be arranged sequentially along the first direction. The first active material portion 311 can be located between the second active material portion 312 and the first conductive element 40. The first conductive element 40 can have a first connecting portion. Along the thickness direction of the first current collector 32, the first connecting portion can be correspondingly disposed with the first protrusion 3222. The first connecting portion can be located on the side of the first protrusion 3222 facing away from the supporting substrate 321. The first connecting portion can be welded to the first protrusion 3222, thereby achieving an electrical connection between the first conductive element 40 and the metal layer 322. The first connecting portion can be welded to the first protrusion 3222, thereby forming a first solder mark 91. The first solder mark 91 can be an integral structure, or the first solder mark 91 can also include multiple spaced solder points or solder lines. The first solder joint 91 can be used to pass through the first connecting part and the first protrusion 3222, which helps to improve the current passing capacity between the first connecting part and the first protrusion 3222.

[0154] like Figure 6 As shown, the first active material portion 311 and the first solder mark portion 91 can be spaced apart along a first direction, and a first gap can be formed between the first active material portion 311 and the first solder mark portion 91. By setting the first gap, when the first connecting portion is welded to the first protrusion 3222, the risk of the solder head contacting the first active material portion 311 can be reduced, the problem of incomplete soldering can be reduced, and the reliability of the connection between the first connecting portion and the first protrusion 3222 can be improved.

[0155] In the above technical solution, the electrode assembly 20 further includes a first conductive element 40, which has a first connecting portion. The first connecting portion is welded to the first protrusion 3222, thereby realizing the electrical connection between the first conductive element 40 and the metal layer 322. The first connecting portion can be welded to the first protrusion 3222 to form a first solder mark 91. Current can pass between the first connecting portion and the first protrusion 3222 through the first solder mark 91, which is beneficial to improving the current passing capacity between the first connecting portion and the first protrusion 3222. By setting a first gap between the first active material portion 311 and the first solder mark 91, the problem of poor soldering can be reduced, which is beneficial to improving the reliability of the connection between the first connecting portion and the first protrusion 3222.

[0156] According to some embodiments of this application, such as Figure 6 As shown, the first electrode 30 may further include a protective layer 70, at least a portion of which is located on the side of the first connecting portion away from the first protrusion 3222 and fixed to the first connecting portion, and the protective layer 70 covers the first solder mark portion 91.

[0157] The protective layer 40 can be configured as an insulating component. At least a portion of the protective layer 70 can be located on the side of the first connecting portion away from the first protrusion 3222 along the thickness direction of the first current collector 32. At least a portion of the protective layer 70 can be bonded to the first connecting portion, thus protecting the first connecting portion. Along the thickness direction of the first current collector 32, the protective layer 70 can isolate the first connecting portion from other structural components, effectively protecting the first conductive component 40. The protective layer 70 can cover the first solder mark 91, and both ends of the first solder mark 91 along the first direction can not extend beyond both ends of the protective layer 70 along the first direction. This reduces the risk of exposure of the first solder mark 91, lowers the risk of the first solder mark 91 puncturing the separator 60, and further improves the reliability of the battery cell 1.

[0158] Along the thickness direction of the first current collector 32, one side of the first solder mark 91 can extend to the side of the first connection portion away from the first protrusion 3222, and the other side of the first solder mark 91 can extend to the side of the first protrusion 3222 away from the first connection portion. This can increase the flow area between the first protrusion 3222 and the first connection portion, improve the flow capacity between the first connection portion and the first protrusion 3222, reduce the risk of heat generation, and further improve the reliability of the connection between the first protrusion 3222 and the first connection portion, thereby improving the fast charging performance and reliability of the battery cell 1.

[0159] In the above technical solution, the protective layer 70 can protect the first connection portion, which is beneficial for protecting the first conductive component 40. The protective layer 70 can isolate the first connection portion from other structural components. The protective layer 70 covers the first solder mark 91, which can reduce the risk of the first solder mark 91 being exposed, reduce the risk of the first solder mark 91 puncturing the separator 60, further improve the reliability of the connection between the first protrusion 3222 and the first connection portion, further reduce the risk of short circuit in the battery cell 1, and further improve the reliability of the battery cell 1.

[0160] According to some embodiments of this application, such as Figure 6 As shown, the first conductive element 40 includes an extension 41 connected to the first connecting portion. The extension 41 is located on the side of the first connecting portion near the second active material portion 312. At least a portion of the extension 41 is located within the first gap. The extension 41 is not welded to the first protrusion 3222.

[0161] The first conductive element 40 may include an extension 41, which may be connected to the first connecting portion and integrally formed with it. The extension 41 may be located on the side of the first connecting portion near the second active material portion 312, and may extend toward the second active material portion 312. The extension 41 may extend to the first gap, and at least a portion of the extension 41 may be located within the first gap. Along the first direction, the end of the extension 41 facing away from the first connecting portion may extend beyond the end of the first solder mark 91 facing the first active material portion 311. The extension 41 is not welded to the first protrusion 3222, but may contact or separate from the first protrusion 3222. The extension 41 may improve the structural strength of the first protrusion 3222 located at the first gap, reduce the probability of the metal layer 322 at the first gap folding or deforming, and further improve the reliability of the battery cell 1.

[0162] In the above technical solution, heat is generated during the welding process, and the first conductive component 40 may deform. By providing an extension 41, which is not welded to the first protrusion 3222, space can be provided for the deformation of the first connection part to a certain extent, reducing stress concentration caused by deformation. When the first connection part cools and shrinks, the extension 41 can adapt to the overall deformation trend of the first conductive component 40, thereby reducing the stress at the first solder mark 91, improving the stability and reliability of the first solder mark 91, and reducing the generation of defects such as cracks. Furthermore, the extension 41 can extend so that at least a portion of the extension 41 is located within the first gap, which can improve the structural strength of the first protrusion 3222 located at the first gap, reduce the probability of the metal layer 322 at the first gap folding or deforming, and further improve the reliability of the battery cell 1.

[0163] According to some embodiments of this application, such as Figure 6 As shown, from the direction of the first conductive element 40 to the first active material portion 311, the extension portion 41 and the first active material portion 311 are spaced apart to form a second gap 33 between the extension portion 41 and the first active material portion 311. The protective layer 70 covers the extension portion 41, and at least a portion of the protective layer 70 is located at the second gap 33 and fixed to the first protrusion 3222.

[0164] In this context, along the first direction from the first conductive element 40 to the first active material portion 311, the extension portion 41 and the first active material portion 311 can be spaced apart, and a second gap 33 can be formed between the extension portion 41 and the first active material portion 311. When the first connecting portion is welded to the first protrusion 3222, the risk of the welding head contacting the first active material portion 311 can be further reduced, the problem of incomplete welding can be further reduced, and the reliability of the connection between the first connecting portion and the first protrusion 3222 can be further improved.

[0165] The protective layer 70 can extend to the second gap 33, with at least a portion of the protective layer 70 located at the second gap 33, and can fill at least a portion of the second gap 33. The protective layer 70 can cover the extension 41, which can improve the integrity of the first connecting portion, the extension 41, and the first protrusion 3222, and reduce the probability of damage to the extension 41. The protective layer 70 can be fixedly connected to the first protrusion 3222 located at the second gap 33, thereby improving the structural strength of the first protrusion 3222 located at the second gap 33, reducing the probability of the metal layer 322 located at the second gap 33 folding or deforming, and reducing the probability of the metal layer 322 cracking and failing, which would affect the overcurrent performance of the metal layer 322, thus further improving the reliability of the battery cell 1.

[0166] The protective layer 70 can be fixedly connected to the first protrusion 3222, and at least a portion of the protective layer 70 is also fixed to the first connecting portion, thereby further improving the connection strength between the first connecting portion and the first protrusion 3222, improving the structural strength and stability of the electrode assembly 20, and enabling the electrode assembly 20 to withstand certain external forces and vibrations without being damaged.

[0167] In the above technical solution, the protective layer 70 covers the extension 41, which can improve the integrity of the first connecting part, the extension 41 and the first protrusion 3222, and reduce the probability of damage to the extension 41. The protective layer 70 can fill at least part of the second gap 33, thereby improving the structural strength of the first protrusion 3222 located at the second gap, reducing the probability of the metal layer 322 located at the second gap 33 folding or deforming, reducing the probability of the metal layer 322 cracking and failing, which would affect the current-carrying performance of the metal layer 322, and further improving the connection strength between the first connecting part and the first protrusion 3222. This can improve the structural strength and stability of the electrode assembly 20, enabling the electrode assembly 20 to withstand certain external forces and vibrations without damage, which is more conducive to improving the reliability of the battery cell 1.

[0168] According to some embodiments of this application, at least a portion of the second gap 33 has a protective layer 70.

[0169] The protective layer 70 can fill at least a portion of the second gap 33, or it can completely fill the second gap 33. This can further improve the structural strength of the first protrusion 3222 located in the second gap 33, further reduce the probability of the metal layer 322 located in the second gap 33 folding or deforming, further reduce the probability of the metal layer 322 cracking and failing, thus affecting the overcurrent performance of the metal layer 322, and further improve the reliability of the battery cell 1.

[0170] In the above technical solution, by setting at least a portion of the second gap 33 to have a protective layer 70, the structural strength of the metal layer 322 located at the second gap 33 can be further improved, the probability of the first current collector 32 located at the second gap 33 being flipped or deformed can be further reduced, the probability of the metal layer 322 cracking and failing and affecting the current flow performance of the metal layer 322 can be further reduced, which is more conducive to improving the reliability of the battery cell 1.

[0171] According to some embodiments of this application, such as Figure 6 As shown, the protective layer 70 extends to the first active material portion 311 to cover a portion of the first active material portion 311.

[0172] The protective layer 70 can extend to the first active material portion 311, completely filling the gap between the first active material portion 311 and the first conductive element 40. This further enhances the structural strength of the first protrusion 3222 located at the second gap 33, reduces the probability of the metal layer 322 at the second gap 33 folding or deforming, and better reduces the probability of the metal layer 322 cracking and failing, thus affecting its overcurrent performance. This is more conducive to improving the reliability of the battery cell 1. The protective layer 70 can connect the first active material portion 311 and the first conductive element 40, further enhancing the connection strength of the components inside the electrode assembly 20 and improving the structural stability of the electrode assembly 20.

[0173] The protective layer 70 covers a portion of the first active material portion 311. The protective layer 70 can bind the edge area of ​​the first active material portion 311, which can reduce the risk of the edge area of ​​the first active material portion 311 collapsing or falling off due to stress concentration. This is beneficial to improving the structural stability of the first active material portion 311 and further improving the reliability of the battery cell 1.

[0174] In the above technical solution, the protective layer 70 can completely fill the gap between the first active material part 311 and the first conductive element 40, which can further improve the structural strength of the first protrusion 3222 located at the second gap. The protective layer 70 covers the part of the first active material part 311, which is beneficial to improving the structural stability of the first active material part 311 and further improving the reliability of the battery cell 1.

[0175] According to some embodiments of this application, the protective layer 70 covers a portion of the first active material portion 311, and the protective layer 70 and the second active material portion 312 are spaced apart.

[0176] The protective layer 70 can extend to the first active material portion 311, and can cover a portion of the first active material portion 311. Along the first direction, when the height of the protective layer 70 covering the first active material portion 311 is less than the height of the first active material portion 311, thus spacing the protective layer 70 from the second active material portion 312, the probability of an increase in the thickness of the second active material portion 312 along the thickness direction of the first current collector 32 can be reduced. This reduces the risk of internal short circuits in the battery cell 1 and helps to further improve the reliability of the battery cell 1.

[0177] In the above technical solution, by setting the protective layer 70 and the second active material part 312 at intervals, the probability of the thickness of the second active material part 312 increasing along the thickness direction of the first current collector 32 can be reduced, thereby reducing the risk of internal short circuit in the battery cell 1 and further improving the reliability of the battery cell 1.

[0178] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the height dimension of the protective layer 70 covering the first active material portion 311 is greater than 0 mm and less than or equal to 1 mm.

[0179] Among them, such as Figure 6 As shown, along the first direction, the height of the protective layer 70 covering the first active material portion 311 is H2, satisfying the relationship: 0mm < H2 ≤ 1mm. For example, the height of the protective layer 70 covering the first active material portion 311 can be 0.1mm, 0.3mm, 0.7mm, 1mm, etc. The height of the protective layer 70 covering the first active material portion 311 can be within the range of 0mm to 1mm, and these are all optional heights of the protective layer 70 covering the first active material portion 311 in this application. If the height of the protective layer 70 covering the first active material portion 311 is equal to 0mm, then the protective layer 70 does not cover the first active material portion 311. If the height of the protective layer 70 covering the first active material portion 311 is greater than 1 mm, the protective layer 70 may cover the second active material portion 312, increasing the thickness at the second active material portion 312. This local thickening of the first electrode 30 leads to inconsistent magnitude and direction of expansion force, potentially causing deformation of the internal structure of the first electrode 30 and possibly resulting in an internal short circuit in the battery cell 1, affecting the reliability and service life of the battery cell 1. Therefore, the height of the protective layer 70 covering the first active material portion 311 is between 0 mm and 1 mm. The protective layer 70 can cover a portion of the first active material portion 311 without covering the second active material portion 312. This reduces the probability of local thickening of the first electrode 30 causing deformation of the internal structure of the first electrode 30 and an internal short circuit in the battery cell 1, which is beneficial for further improving the reliability of the battery cell 1 and extending its service life.

[0180] In the above technical solution, by setting a protective layer 70 to cover the first active material part 311 with a height dimension greater than 0 mm and less than or equal to 1 mm along the first direction, the protective layer 70 can cover part of the first active material part 311 and prevent the protective layer 70 from covering the second active material part 312. This reduces the probability of deformation of the internal structure of the first electrode 30 and internal short circuit of the battery cell 1 caused by local thickening of the first electrode 30, which is beneficial to further improve the reliability of the battery cell 1 and further extend the service life of the battery cell 1.

[0181] According to some embodiments of this application, the thickness dimension of the overlap between the protective layer 70 and the first active material portion 311 along the thickness direction of the first current collector 32 is less than or equal to the thickness dimension of the second active material portion 312.

[0182] During the production and processing of the first electrode 30, it needs to be processed through processes such as rolling. The protective layer 70 can cover a portion of the first active material portion 311, allowing the protective layer 70 and the first active material portion 311 to have an overlapping portion. It should be noted that the thickness dimension along the thickness direction of the first current collector 32 at the overlapping location of the protective layer 70 and the first active material portion 311 refers to the sum of the thickness dimension of the protective layer 70 along the thickness direction of the first current collector 32 and the thickness dimension of the first active material portion 311 along the thickness direction of the first current collector 32. If the thickness of the overlap between the protective layer 70 and the first active material portion 311 along the thickness direction of the first current collector 32 is greater than the thickness of the second active material portion 312, it will cause uneven tension in the first electrode 30 during the rolling process and will restrict the volume change of the first active material portion 311. When the first active material portion 311 deforms, it will cause an increase in internal stress, leading to cracking, detachment, and other phenomena, affecting the cycle life of the battery cell 1. Therefore, by setting the thickness of the overlap between the protective layer 70 and the first active material portion 311 along the thickness direction of the first current collector 32 to be less than or equal to the thickness of the second active material portion 312, the risk of uneven tension in the first electrode 30 during the rolling process can be reduced, and the internal stress of the first active material portion 311 when it deforms can be reduced. This is beneficial to improving the structural stability of the first active material portion 311 and can further improve the stability and integrity of the battery cell 1.

[0183] By rationally setting the thickness dimension of the overlap between the protective layer 70 and the first active material portion 311 along the thickness direction of the first current collector 32, it is beneficial to maintain the uniformity of the internal structure of the battery cell 1. If the overlapping part is too thick, it will lead to inconsistent thickness and performance of various parts inside the battery cell 1, which can easily cause problems such as local overheating, overcharging, and over-discharging during charging and discharging, affecting the overall performance and reliability of the battery cell 1. By setting the thickness dimension of the overlap between the protective layer 70 and the first active material portion 311 along the thickness direction of the first current collector 32 to match the thickness dimension of the second active material portion 312, the internal structure of the battery cell 1 can be made more uniform, and the current distribution more balanced, which is beneficial to improving the stability and reliability of the battery cell 1. Furthermore, it reduces the risk of uneven tension of the first electrode 30 when the first electrode 30 is processed by rolling.

[0184] In the above technical solution, by setting the thickness dimension of the overlap between the protective layer 70 and the first active material part 311 along the thickness direction of the first current collector 32 to be less than or equal to the thickness dimension of the second active material part 312, the risk of uneven tension of the first electrode 30 can be reduced when the first electrode 30 is processed by rolling. This can help improve the structural stability of the first active material part 311, make the internal structure of the battery cell 1 more uniform, and help to better improve the stability, integrity and reliability of the battery cell 1.

[0185] According to some embodiments of this application, such as Figure 6 As shown, in the direction from the first conductive element 40 to the first active material portion 311, the inner end of the protective layer 70 protrudes from the inner end of the extension portion 41.

[0186] Among them, such as Figure 6 As shown, from the direction of the first conductive element 40 to the first active material portion 311, the inner end of the protective layer 70 can protrude beyond the inner end of the extension portion 41. The inner end of the protective layer 70 can be located below the inner end of the extension portion 41. The protective layer 70 can cover the inner end of the extension portion 41, thereby reducing the risk of exposure of the extension portion 41. It can isolate the extension portion 41 from other internal components of the battery cell 1, reduce the probability of short circuit and damage to the battery cell 1, further extend the service life of the battery cell 1, and improve the reliability of the battery cell 1.

[0187] It should be noted that, from the direction of the first conductive element 40 to the first active material portion 311, the end of the protective layer 70 and the extension portion 41 closest to the first active material portion 311 is the inner end.

[0188] The above technical solution can reduce the risk of exposure of the extension 41, which is conducive to further extending the service life of the battery cell 1 and further improving the reliability of the battery cell 1.

[0189] According to some embodiments of this application, such as Figure 7 As shown, from the direction of the first conductive element 40 to the first active material portion 311, the extension portion 41 extends to the first active material portion 311 to cover a portion of the first active material portion 311.

[0190] In this embodiment, the extension portion 41 can extend to the first active material portion 311 from the direction of the first conductive element 40 to the first active material portion 311. The extension portion 41 can cover a portion of the first active material portion 311 and can abut against the surface of the first active material portion 311. This can increase the contact area between the first conductive element 40 and the first active material portion 311, increase the current flow area, improve the conductivity of the electrode assembly 20, and further improve the structural strength of the metal layer 322 located in the gap between the first active material portion 311 and the first conductive element 40. This can further reduce the probability of the metal layer 322 in the gap between the first active material portion 311 and the first conductive element 40 folding or deforming, and further reduce the probability of the metal layer 322 cracking and failing, which would affect the current flow performance of the metal layer 322. This is more conducive to improving the reliability of the battery cell 1.

[0191] The extension 41 covers the portion of the first active material portion 311. The extension 41 can bind the edge area of ​​the first active material portion 311, which can reduce the risk of the edge area of ​​the first active material portion 311 collapsing or falling off due to stress concentration. This is beneficial to further improve the structural stability of the first active material portion 311 and further improve the reliability of the battery cell 1.

[0192] In the above technical solution, the extension 41 covers the portion of the first active material portion 311, which can increase the contact area between the first conductive element 40 and the first active material portion 311, increase the current flow area, improve the conductivity of the electrode assembly 20, and further improve the structural strength of the metal layer 322 located in the gap between the first active material portion 311 and the first conductive element 40. It can further reduce the probability of the metal layer 322 located in the gap between the first active material portion 311 and the first conductive element 40 folding or deforming, which is conducive to further improving the structural stability of the first active material portion 311 and further improving the reliability of the battery cell 1.

[0193] According to some embodiments of this application, such as Figure 7 As shown, from the direction of the first conductive element 40 to the first active material portion 311, the edge of the protective layer 70 extends beyond the edge of the first solder mark portion 91.

[0194] In the direction from the first conductive element 40 to the first active material portion 311, the edge of the protective layer 70 may extend beyond the edge of the first solder mark portion 91. In other words, the edge of the protective layer 70 may be located below the edge of the first solder mark portion 91, thereby further reducing the risk of exposure of the first solder mark portion 91, further reducing the risk of the first solder mark portion 91 puncturing the separator 60, and further improving the reliability of the battery cell 1.

[0195] In the above technical solution, by setting the edge of the protective layer 70 to extend beyond the edge of the first solder mark 91, the risk of the first solder mark 91 being exposed can be further reduced, the risk of the first solder mark 91 puncturing the separator 60 can be further reduced, and the reliability of the battery cell 1 can be further improved.

[0196] According to some embodiments of this application, such as Figure 7 As shown, the end of the extension 41 near the first active material portion 311 is formed with a bent structure 411 that bends toward the direction away from the first protrusion 3222, so that the bent structure 411 covers the first active material portion 311.

[0197] Along the first direction, a bending structure 411 can be formed at the end of the extension 41 near the first active material portion 311. The bending structure 411 can be bent in a direction away from the first protrusion 3222, and the bending structure 411 can be constructed as an arc shape, so that the extension 41 can extend to the first active material portion 311. The bending structure 411 can cover a part of the first active material portion 311, and the bending structure 411 can abut against the first active material portion 311. The bending structure 411 can restrain the edge area of ​​the first active material portion 311, which can further reduce the risk of the edge area of ​​the first active material portion 311 collapsing or falling off due to stress concentration. This is beneficial to further improving the structural stability of the first active material portion 311 and further improving the reliability of the battery cell 1. Furthermore, the bending structure 411 can cover the gap between the first active material portion 311 and the first conductive element 40. At least a portion of the bending structure 411 can stably support the first protrusion 3222 located in the gap between the first active material portion 311 and the first conductive element 40. This can further reduce the probability of the first protrusion 3222 located in the gap between the first active material portion 311 and the first conductive element 40 folding or deforming, and further reduce the probability of the metal layer 322 cracking and failing, which would affect the overcurrent performance of the metal layer 322. This is more conducive to improving the reliability of the battery cell 1.

[0198] In the above technical solution, the bending structure 411 can constrain the edge area of ​​the first active material part 311, which is conducive to further improving the structural stability of the first active material part 311. The bending structure 411 can cover the gap between the first active material part 311 and the first conductive element 40, which can further reduce the probability of the first protrusion 3222 located in the gap between the first active material part 311 and the first conductive element 40 folding or deforming, further reduce the probability of the metal layer 322 cracking and failing, which affects the overcurrent performance of the metal layer 322, and is more conducive to further improving the reliability of the battery cell 1.

[0199] According to some embodiments of this application, such as Figure 7As shown, in the direction from the first conductive element 40 to the first active material portion 311, the inner end of the extension portion 41 protrudes from the inner end of the protective layer 70.

[0200] When the extension 41 extends to the first active material portion 311, the extension 41 can cover the gap between the first active material portion 311 and the first conductive element 40, and the protective layer 70 may not completely fill the gap between the first active material portion 311 and the first conductive element 40. From the first conductive element 40 to the first active material portion 311, the inner end of the extension 41 may protrude beyond the inner end of the protective layer 70. Figure 7 As shown, along the first direction, the inner end of the extension 41 can be located below the inner end of the protective layer 70. The protective layer 70 can cover the connection between the extension 41 and the first protrusion 3222, which can reduce the area of ​​the protective layer 70 and the material of the protective layer 70, thus helping to reduce costs.

[0201] In the above technical solution, the protective layer 70 may not completely fill the gap between the first active material part 311 and the first conductive element 40, which can reduce the area of ​​the protective layer 70 and the material of the protective layer 70, thus helping to reduce costs.

[0202] According to some embodiments of this application, such as Figure 7 As shown, along the first direction, the extension 41 covers the first active material portion 311 with a height dimension greater than 0 mm and less than or equal to 1 mm.

[0203] Among them, such as Figure 7As shown, along the first direction, the height of the extension 41 covering the first active material portion 311 is H3, satisfying the relationship: 0mm < H3 ≤ 1mm. For example, the height of the extension 41 covering the first active material portion 311 can be 0.1mm, 0.3mm, 0.7mm, 1mm, etc. The height of the extension 41 covering the first active material portion 311 can be within the range of 0mm to 1mm, and these are all optional heights of the extension 41 covering the first active material portion 311 in this application. If the height of the extension 41 covering the first active material portion 311 is equal to 0mm, then the extension 41 does not cover the first active material portion 311. If the height of the extension 41 covering the first active material portion 311 is greater than 1 mm, the extension 41 may cover the second active material portion 312, increasing the thickness of the second active material portion 312. During the thickening process, the first electrode 30 will generate expansion force. Local thickening of the first electrode 30 can lead to inconsistent magnitude and direction of the expansion force, potentially causing deformation of the internal structure of the first electrode 30 and possibly resulting in an internal short circuit in the battery cell 1, affecting the reliability and lifespan of the battery cell 1. Therefore, the height of the extension 41 covering the first active material portion 311 is between 0 mm and 1 mm. The extension 41 can cover a portion of the first active material portion 311 without covering the second active material portion 312. This reduces the probability of local thickening of the first electrode 30 causing deformation of the internal structure of the first electrode 30 and an internal short circuit in the battery cell 1, further improving the reliability of the battery cell 1 and extending its lifespan.

[0204] In the above technical solution, by setting the extension 41 to cover the first active material part 311 with a height dimension greater than 0 mm and less than or equal to 1 mm along the first direction, the extension 41 can cover part of the first active material part 311 and prevent the extension 41 from covering the second active material part 312, thereby reducing the probability of deformation of the internal structure of the first electrode 30 and internal short circuit of the battery cell 1 caused by local thickening of the first electrode 30, which is beneficial to further improve the reliability of the battery cell 1 and further extend the service life of the battery cell 1.

[0205] According to some embodiments of this application, the thickness dimension of the overlapping part of the extension 41 and the first active material part 311 along the thickness direction of the first current collector 32 is less than or equal to the thickness dimension of the second active material part 312.

[0206] During the production and processing of the first electrode 30, it needs to be processed through processes such as rolling. The extension 41 can cover a portion of the first active material portion 311, and the extension 41 and the first active material portion 311 have an overlapping portion. If the thickness dimension of the overlapping area of ​​the extension 41 and the first active material portion 311 along the thickness direction of the first current collector 32 is greater than the thickness dimension of the second active material portion 312, it will cause local thickening of the first electrode 30, resulting in uneven tension on the first electrode 30 during the rolling process. It should be noted that the thickness dimension of the overlapping area of ​​the extension 41 and the first active material portion 311 along the thickness direction of the first current collector 32 refers to the sum of the thickness dimension of the extension 41 along the thickness direction of the first current collector 32 and the thickness dimension of the first active material portion 311 along the thickness direction of the first current collector 32 at the overlapping position. Uneven tension may cause changes in the internal structure of the first electrode 30, thereby reducing the conductivity of the battery cell 1, decreasing the charge and discharge efficiency, and affecting the overall performance of the battery cell 1. It will also affect the transport of lithium ions at the location of local thickening of the first electrode 30 during the lithium intercalation process, thereby causing the capacity of the battery cell 1 to gradually decrease.

[0207] In the above technical solution, by setting the thickness dimension of the overlapping part of the extension 41 and the first active material part 311 along the thickness direction of the first current collector 32 to be less than or equal to the thickness dimension of the second active material part 312, the probability of uneven tension generated by the first electrode 30 can be reduced, thereby reducing the risks of decreased conductivity, reduced charge and discharge efficiency, and impact on the overall performance of the battery cell 1. Furthermore, the first electrode 30 can maintain good structural stability and lithium-ion transport performance during lithium intercalation, minimizing lithium-ion loss and thus slowing down the rate of decrease in battery capacity. This is more conducive to giving the battery cell 1 better charge and discharge performance and a longer service life.

[0208] According to some embodiments of this application, along the first direction, the height dimension of the first solder mark 91 is greater than or equal to 1.5 mm and less than or equal to 3 mm.

[0209] Among them, such as Figure 6As shown, along the first direction, the height of the first solder mark 91 is H4, satisfying the relationship: 1.5mm ≤ H4 ≤ 3mm. For example, the height of the first solder mark 91 can be 1.5mm, 1.9mm, 2.2mm, 2.7mm, 3mm, etc. The height of the first solder mark 91 can be within the range of 1.5mm to 3mm, including any value including the endpoint value; any value is acceptable for the height of the first solder mark 91 in this application. If the height of the first solder mark 91 is less than 1.5mm, it is prone to causing poor soldering, resulting in a small current-carrying area between the first protrusion 3222 and the first connection portion, affecting the current-carrying capacity between the first connection portion and the first protrusion 3222. If the height of the first solder mark 91 is greater than 3mm, the space occupied by the first conductive element 40 increases, further reducing the energy density of the battery cell 1. Therefore, the height of the first solder mark 91 is between 1.5mm and 3mm, which can further enhance the current flow capacity between the first connection part and the first protrusion 3222, reduce the space occupied by the first conductive element 40, and further improve the energy density of the battery cell 1.

[0210] In the above technical solution, by setting the height dimension of the first solder mark 91 along the first direction to be greater than or equal to 1.5 mm and less than or equal to 3 mm, the current flow capacity between the first connecting part and the first protrusion 3222 can be further enhanced, the space occupied by the first conductive element 40 can be reduced, and the energy density of the battery cell 1 can be further improved.

[0211] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the distance between the first solder mark portion 91 and the first active material portion 311 is greater than or equal to 0.1 mm and less than or equal to 1 mm.

[0212] Among them, such as Figure 6As shown, along the first direction, the distance between the first solder mark 91 and the first active material part 311 is L1, that is, the height dimension of the first gap along the first direction is L1, satisfying the relationship: 0.1mm≤L1≤1mm. For example, the distance between the first solder mark 91 and the first active material part 311 can be 0.1mm, 0.3mm, 0.7mm, 1mm, etc. The distance between the first solder mark 91 and the first active material part 311 can be within the range of 0.1mm to 1mm. Any value, including the endpoint value, is an optional distance between the first solder mark 91 and the first active material part 311 in this application. If the distance between the first solder mark 91 and the first active material part 311 is less than 0.1mm, the solder head may come into contact with the first active material part 311 during soldering, which may lead to a cold solder joint. If the distance between the first solder mark 91 and the first active material portion 311 is greater than 1 mm, the first protrusion 3222 of the first electrode 30 is prone to folding and deformation after die cutting, affecting the reliability of the first conductive element 40. Therefore, the distance between the first solder mark 91 and the first active material portion 311 is between 0.1 mm and 1 mm, which can reduce the probability of incomplete soldering during welding and improve the reliability of the first conductive element 40.

[0213] In the above technical solution, by setting the interval between the first solder mark 91 and the first active material part 311 along the first direction to be greater than or equal to 0.1 mm and less than or equal to 1 mm, the probability of cold solder joints during welding can be reduced, and the reliability of the first electrode 30 can be improved.

[0214] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the protective layer 70 completely covers the first solder mark 91.

[0215] The protective layer 70 can completely cover the first solder mark 91, meaning that neither end of the first solder mark 91 along the first direction extends beyond the ends of the protective layer 70 along the first direction. In other words, from the direction from the first conductive element 40 to the first active material portion 311, the edge of the protective layer 70 extends beyond the edge of the first solder mark 91, and from the direction from the first active material portion 311 to the first conductive element 40, the edge of the protective layer 70 extends beyond the edge of the first solder mark 91. The protective layer 70 can cover the inner end of the first solder mark 91 and the outer end of the first solder mark 91. The protective layer 70 can shield burrs, metal debris, and other structures on the first solder mark 91, thereby further reducing the risk of the first solder mark 91 being exposed, further reducing the risk of the first solder mark 91 puncturing the separator 60, and further improving the reliability of the battery cell 1.

[0216] It should be noted that, from the direction of the first conductive element 40 to the first active material portion 311, the end of the protective layer 70 and the first solder mark portion 91 closest to the first active material portion 311 is the inner end. From the direction of the first active material portion 311 to the first conductive element 40, the end of the protective layer 70 and the first solder mark portion 91 opposite to the first active material portion 311 is the outer end.

[0217] In the above technical solution, the protective layer 70 can shield the burrs, metal debris and other structures on the first solder mark 91, thereby further reducing the risk of the first solder mark 91 being exposed, further reducing the risk of the first solder mark 91 puncturing the separator 60, and further improving the reliability of the battery cell 1.

[0218] According to some embodiments of this application, such as Figure 5 and Figure 6 As shown, there are two metal layers 322 and two active material layers 31. Along the thickness direction of the first current collector 32, the two metal layers 322 are respectively disposed on opposite sides of the support substrate 321, and the two active material layers 31 are respectively disposed on the side of the two metal layers 322 away from the support substrate 321. The first conductive element 40 is provided on both sides of the first current collector 32. The first conductive elements 40 on both sides of the first current collector 32 are arranged opposite to each other, and the first conductive element 40 is connected to the metal layer 322 on the corresponding side.

[0219] The first current collector 32 may include two metal layers 322, two active material layers 31, and a supporting substrate 321. There may be two metal layers 322, which are respectively disposed on opposite sides of the supporting substrate 321 along the thickness direction of the first current collector 32. There may also be two active material layers 31, which are respectively disposed on the side of the two metal layers 322 away from the supporting substrate 321, and the two active material layers 31 may respectively cover the two metal layers 322.

[0220] Along the thickness direction of the first current collector 32, first conductive elements 40 can be provided on both sides of the first current collector 32. Each first protrusion 3222 can be connected to one first conductive element 40. The first conductive elements 40 located on both sides of the first current collector 32 are arranged opposite to each other along the thickness direction of the first current collector 32. Each first conductive element 40 can be connected to the corresponding side metal layer 322. The first connecting portion of each first conductive element 40 can be welded to the first protrusion 3222 of the corresponding side metal layer 322, thereby forming two first solder marks 91.

[0221] like Figure 5As shown, along the length direction of the first electrode 30, each metal layer 322 can form a plurality of first protrusions 3222. The plurality of first protrusions 3222 of each metal layer 322 can be arranged sequentially along the length direction of the first electrode 30. The plurality of first protrusions 3222 of each metal layer 322 can be spaced apart. Each first protrusion 3222 can be provided with a first conductive element 40 on the side away from the support substrate 321. Along the thickness direction of the first current collector 32, two metal layers 322 can be respectively disposed on opposite sides of the support substrate 321. Multiple first conductive elements 40 on both sides of the first current collector 32 can be arranged opposite each other along the thickness direction of the first current collector 32. The first electrode 30 has two groups of first conductive elements, which are respectively disposed on both sides of the first current collector 32. The metal layers 322 and the first conductive elements are connected in a one-to-one correspondence. Each group of first conductive elements includes multiple first conductive elements 40. The multiple first conductive elements 40 in each group of first conductive elements are connected in a one-to-one correspondence with the multiple first protrusions 3222 of the corresponding metal layer 322. The multiple first conductive elements 40 in one group of first conductive elements and the multiple first conductive elements 40 in another group of first conductive elements are arranged opposite each other along the thickness direction of the first current collector 32.

[0222] In the above technical solution, by setting two metal layers 322 and two active material layers 31, the two active material layers 31 can increase the contact area between the first current collector 32 and the electrolyte, which is beneficial to improving the charge and discharge capacity of the battery cell 1. At the same time, the two metal layers 322 can better collect and conduct electrons, which can improve the charge and discharge efficiency of the battery cell 1 and reduce energy loss. Furthermore, the first current collector 32 can be connected to multiple first conductive elements 40, which can further enhance the overcurrent performance of the battery cell 1.

[0223] According to some embodiments of this application, the first conductive elements 40 on both sides of the first current collector 32 are parallel or approximately parallel to each other.

[0224] Along the thickness direction of the first current collector 32, the first conductive elements 40 located on both sides of the first current collector 32 can be connected to the corresponding first protrusions 3222. The two first conductive elements 40 arranged opposite each other along the thickness direction of the first current collector 32 are parallel or approximately parallel to each other, so that the current can be evenly conducted and distributed on both sides of the first current collector 32. This can reduce problems such as local overheating of the battery cell 1 and inconsistent battery performance caused by uneven current distribution, thereby further improving the stability of the battery cell 1. If the first conductive elements 40 on both sides of the first current collector 32 are parallel to each other, the two parallel first conductive elements 40 are convenient for standardized production and assembly during the manufacturing process of the battery cell 1, which is conducive to further improving the production efficiency of the battery cell 1.

[0225] In the above technical solution, by setting the first conductive elements 40 on both sides of the first current collector 32 to be parallel or approximately parallel to each other, the current can be evenly conducted and distributed on both sides of the first current collector 32, which can further improve the overall performance and stability of the battery cell 1. If the first conductive elements 40 on both sides of the first current collector 32 are set to be parallel to each other, the production efficiency of the battery cell 1 can also be further improved.

[0226] According to some embodiments of this application, such as Figure 7 As shown, from the first active material portion 311 to the first conductive element 40, the outer end of the protective layer 70 protrudes from the outer end of the first solder mark portion 91.

[0227] In this embodiment, from the first active material portion 311 to the first conductive element 40, the outer end of the protective layer 70 may protrude beyond the outer end of the first solder mark portion 91. Along the first direction, the outer end of the protective layer 70 may be located above the outer end of the first solder mark portion 91, and the protective layer 70 may cover the outer end of the first solder mark portion 91. The protective layer 70 can reduce the risk of exposure of the first solder mark portion 91. The protective layer 70 can shield burrs, metal debris, and other structures on the first solder mark portion 91, thereby reducing the risk of these structures passing through the separator 60 and contacting other components, which is beneficial to further improving the reliability of the battery cell 1.

[0228] It should be noted that, from the direction of the first active material portion 311 to the first conductive element 40, the end of the protective layer 70 and the first solder mark portion 91 that is away from the first active material portion 311 is the outer end.

[0229] As an example, such as Figure 7 As shown, along the first direction, the distance by which the outer end of the protective layer 70 protrudes beyond the outer end of the first solder mark 91 is L2, satisfying the relationship: 0mm < L2 ≤ 0.5mm. For example, the distance by which the outer end of the protective layer 70 protrudes beyond the outer end of the first solder mark 91 can be 0.1mm, 0.2mm, 0.35mm, 0.5mm, etc. The distance between the outer end of the protective layer 70 and the outer end of the first solder mark 91 can be within the range of 0mm to 0.5mm, all of which are optional distances for the outer end of the protective layer 70 protruding beyond the outer end of the first solder mark 91 in this application. If the distance by which the outer end of the protective layer 70 protrudes beyond the outer end of the first solder mark 91 is equal to 0mm, then the outer end of the protective layer 70 does not protrude beyond the outer end of the first solder mark 91. If the distance by which the outer end of the protective layer 70 protrudes beyond the outer end of the first solder mark 91 is greater than 0.5mm, then the height dimension of the protective layer 70 along the first direction will be too large, leading to an increase in the cost of the protective layer 70. Therefore, the distance by which the outer end of the protective layer 70 protrudes beyond the outer end of the first solder mark 91 is between 0.1 mm and 1 mm. This not only allows the outer end of the protective layer 70 to protrude beyond the outer end of the first solder mark 91, but also makes the height dimension of the protective layer 70 along the first direction reasonable, reducing material waste.

[0230] In the above technical solution, by setting the outer end of the protective layer 70 to protrude from the outer end of the first solder mark 91 in the direction from the first active material part 311 to the first conductive element 40, the risk of exposure of the first solder mark 91 can be reduced, which is conducive to further improving the reliability of the battery cell 1. Furthermore, by setting the distance between the outer end of the protective layer 70 and the outer end of the first solder mark 91 to be greater than 0 mm and less than or equal to 0.5 mm, the outer end of the protective layer 70 can protrude from the outer end of the first solder mark 91, and the height dimension of the protective layer 70 along the first direction can be reasonable, reducing material waste.

[0231] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the first conductive element 40 includes a first connecting portion and a second connecting portion 42, the first connecting portion and the second connecting portion 42 are connected together, the second connecting portion 42 protrudes from the first active material portion 311 in the direction to the first conductive element 40 from the first protrusion 3222, the two second connecting portions 42 are welded to form a second solder mark 92, and a protective layer 70 covers at least a portion of the second solder mark 92.

[0232] In this embodiment, along the first direction, the first conductive element 40 may include a first connecting portion and a second connecting portion 42. The first connecting portion and the second connecting portion 42 may be arranged along the first direction, with the first connecting portion located below the second connecting portion 42. The first connecting portion and the second connecting portion 42 are connected and may be integrally formed. The second connecting portion 42 may protrude from the first protrusion 3222 in the direction from the first active material portion 311 to the first conductive element 40. Along the thickness direction of the first current collector 32, first conductive elements 40 are provided on both sides of the first current collector 32. The two second connecting portions 42 may be welded together to form a second solder mark 92.

[0233] As an example, along the thickness direction of the first current collector 32, the second connecting portion 42 located on one side of the first current collector 32 can be bent toward the corresponding second connecting portion 42 located on the other side of the first current collector 32, and the second connecting portion 42 located on one side of the first current collector 32 can be welded to the second connecting portion 42 located on the other side of the first current collector 32. The two second connecting portions 42 located on both sides of the first current collector 32 are connected to each other, thereby forming a second solder mark 92. As another example, along the thickness direction of the first current collector 32, the two second connecting portions 42 located on both sides of the first current collector 32 can be bent toward each other, and the two second connecting portions 42 can be welded together. The two second connecting portions 42 located on both sides of the first current collector 32 are connected to each other, thereby forming a second solder mark 92.

[0234] The second solder mark 92 can be adjacent to the first solder mark 91, or the second solder mark 92 can be separated from the first solder mark 91, both of which can achieve the effect of welding the two first conductive elements 40 together. In the first current collector 32, the support substrate 321 can insulate the two metal layers 322 apart. The first protrusions 3222 of the two metal layers 322 each have corresponding first conductive elements 40 connected to them. The two first conductive elements 40 arranged opposite to each other along the thickness direction of the first current collector 32 are connected to each other, which can effectively improve the conductivity of the first electrode 30, further improve the fast charging performance of the battery cell 1, and further improve the reliability of the battery cell 1.

[0235] The protective layer 70 can cover at least a portion of the second solder mark 92, thereby reducing the risk of exposure of the second solder mark 92 and the risk of the second solder mark 92 puncturing the separator 60, and improving the reliability of the battery cell 1. Along the thickness direction of the first current collector 32, one side of the second solder mark 92 can extend to the side of the first conductive member 40 on one side of the first current collector 32 that is away from the other side of the first conductive member 40, and the other side of the second solder mark 92 can extend to the side of the first conductive member 40 on the other side of the first current collector 32 that is away from the side of the first conductive member 40 on one side of the first current collector 32. This can increase the current flow area between the two first conductive members 40, improve the current flow capacity between the two first conductive members 40, and improve the connection reliability of the two first conductive members 40, which is beneficial to further improving the fast charging performance and reliability of the battery cell 1.

[0236] In the above technical solution, the first conductive element 40 may include a first connecting portion and a second connecting portion 42, which are connected together. First conductive elements 40 are provided on both sides of the first current collector 32, and both first conductive elements 40 are connected to the metal layer 322 on their respective sides. The second connecting portions 42 of the two first conductive elements 40 are welded together, which can effectively improve the conductivity of the first electrode 30, further improve the fast-charging performance of the battery cell 1, and further improve the reliability of the battery cell 1. Furthermore, the protective layer 70 covers at least a portion of the second solder mark 92, which can reduce the risk of exposure of the second solder mark 92, reduce the risk of the second solder mark 92 puncturing the separator 60, and further improve the reliability of the battery cell 1.

[0237] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the second solder mark 92 and the first solder mark 91 are adjacent to each other.

[0238] The second solder mark 92 can be adjacent to the first solder mark 91. The second solder mark 92 and the first solder mark 91 can be arranged along the first direction. The second solder mark 92 and the first solder mark 91 can form a whole solder mark. The second solder mark 92 and the first solder mark 91 can be processed by one roll welding process, which can achieve the effect of connecting two first conductive parts 40 by one roll welding process. This can improve the integrity of the second solder mark 92 and the first solder mark 91 and improve the processing efficiency of welding and connecting two first conductive parts 40.

[0239] In the above technical solution, the second solder mark 92 and the first solder mark 91 are adjacent to each other, which can improve the integrity of the second solder mark 92 and the first solder mark 91 and improve the processing efficiency of welding the two first conductive parts 40.

[0240] As an example, the length of the first conductive element 40 located on one side of the first current collector 32 along the first direction can be smaller than the length of the first conductive element 40 located on the other side of the first current collector 32 along the first direction, thereby reducing the space occupied by the first conductive element 40 and further improving the energy density of the battery cell 1.

[0241] According to some embodiments of this application, such as Figure 6 As shown, along the first direction, the height of the second solder mark 92 is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0242] Along the first direction, the height of the second solder mark 92 is H5, satisfying the relationship: 0.5mm ≤ H5 ≤ 2mm. For example, the height of the second solder mark 92 can be 0.5mm, 0.9mm, 1.2mm, 2mm, etc., and any value, including the endpoint value, is acceptable within the range of 0.5mm to 2mm. If the height of the second solder mark 92 is less than 0.5mm, it will lead to poor soldering, resulting in a small current-carrying area between the two first conductive elements 40, affecting the current-carrying capacity between them. If the height of the second solder mark 92 is greater than 3mm, the space occupied by the first conductive elements 40 increases, reducing the energy density of the battery cell 1. Therefore, a height of 1.5mm to 3mm for the second solder mark 92 can further enhance the current-carrying capacity of the two first conductive elements 40 and reduce the space occupied by the first conductive elements 40, thereby further improving the energy density of the battery cell 1.

[0243] In the above technical solution, by setting the height dimension of the second soldering part 92 along the first direction to be greater than or equal to 0.5 mm and less than or equal to 2 mm, the current carrying capacity of the two first conductive parts 40 can be further enhanced, the space occupied by the first conductive parts 40 can be reduced, and the energy density of the battery cell 1 can be further improved.

[0244] According to some embodiments of this application, such as Figure 7 As shown, the protective layer 70 completely covers the second solder mark 92.

[0245] The protective layer 70 can completely cover the second solder mark 92, meaning that neither end of the second solder mark 92 along the first direction extends beyond the ends of the protective layer 70 along the first direction. In other words, from the direction of the first conductive element 40 to the first active material portion 311, the edge of the protective layer 70 extends beyond the edge of the second solder mark 92, and from the direction of the first active material portion 311 to the first conductive element 40, the edge of the protective layer 70 extends beyond the edge of the second solder mark 92. The protective layer 70 can cover the inner end of the second solder mark 92 and the outer end of the second solder mark 92. The protective layer 70 can further shield burrs, metal debris, and other structures on the second solder mark 92, thereby further reducing the risk of the second solder mark 92 being exposed, further reducing the risk of the second solder mark 92 puncturing the separator 60, and further improving the reliability of the battery cell 1.

[0246] It should be noted that, from the direction of the first conductive element 40 to the first active material portion 311, the end of the protective layer 70 and the second solder mark portion 92 closest to the first active material portion 311 is the inner end. From the direction of the first active material portion 311 to the first conductive element 40, the end of the protective layer 70 and the second solder mark portion 92 opposite to the first active material portion 311 is the outer end.

[0247] As an example, such as Figure 7As shown, along the first direction, from the first active material portion 311 to the first conductive element 40, the distance by which the edge of the protective layer 70 extends beyond the edge of the second solder portion 92 is L3, satisfying the relationship: 0mm < L3 ≤ 0.5mm. For example, the distance by which the edge of the protective layer 70 extends beyond the edge of the second solder portion 92 can be 0.1mm, 0.2mm, 0.35mm, 0.5mm, etc. The distance from the edge of the protective layer 70 to the edge of the second solder portion 92 can be within the range of 0mm to 0.5mm, all of which are optional distances for the edge of the protective layer 70 extending beyond the edge of the second solder portion 92 in this application. If the distance by which the edge of the protective layer 70 extends beyond the edge of the second solder portion 92 is equal to 0mm, then the edge of the protective layer 70 does not extend beyond the edge of the second solder portion 92. If the distance by which the edge of the protective layer 70 extends beyond the edge of the second solder portion 92 is greater than 0.5mm, then the height dimension of the protective layer 70 along the first direction will be too large, leading to an increase in the cost of the protective layer 70. Therefore, the distance by which the edge of the protective layer 70 extends beyond the edge of the second solder mark 92 is between 0.1 mm and 1 mm. This not only allows the edge of the protective layer 70 to extend beyond the edge of the second solder mark 92, but also makes the height dimension of the protective layer 70 along the first direction reasonable, further reducing material waste.

[0248] In the above technical solution, by setting the protective layer 70 to completely cover the second solder mark 92, the risk of exposure of the second solder mark 92 can be further reduced, which is conducive to further improving the reliability of the battery cell 1. Furthermore, by setting the distance from the edge of the protective layer 70 to the edge of the second solder mark 92 in the direction from the first active material part 311 to the first conductive element 40 to be greater than 0 mm and less than or equal to 0.5 mm, the edge of the protective layer 70 can be made to extend beyond the edge of the second solder mark 92, and the height dimension of the protective layer 70 along the first direction can be made reasonable, which can further reduce material waste.

[0249] According to some embodiments of this application, the protective layer 70 is constructed as an adhesive layer.

[0250] The protective layer 70 can be constructed as an adhesive layer, which can firmly adhere to the surface of the corresponding structural component of the first electrode 30. The adhesive layer can bond tightly with the corresponding structural component, making the protective layer 70 less prone to detachment and providing durable protection. The adhesive layer has a certain degree of flexibility, and when subjected to external impact or vibration, the protective layer 70 can act as a buffer, reducing damage to the corresponding structural component. Furthermore, if the protective layer 70 is partially damaged, the adhesive layer is relatively easy to repair or replace; simply reapply or re-attach the adhesive material to the damaged area, which is low-cost and easy to operate. The adhesive-based protective layer 70 also has good insulation properties, reducing the risk of leakage or short circuits in the corresponding structural component, further improving the reliability of the battery cell 1.

[0251] The protective layer 70 can be configured as an adhesive layer, which covers the surface of the first active material portion 311. The surface of the first active material portion 311 has a high surface energy and can uniformly cover the surface of the first active material portion 311. The adhesive layer may include an adhesive, which plays an important role in bonding the active material particles together and fixing them to the first current collector 32 in the first electrode 30. When the structure of the first active material portion 311 becomes relatively more fragile after being thinned, drying too quickly will aggravate the generation of internal stress and affect the uniform distribution of the adhesive, resulting in low adhesion of some active material particles. This will cause powder to fall off the edges, which will result in the loss of active material in the first electrode 30, reduce the capacity of the battery cell 1, and the fallen powder may accumulate inside the battery cell 1, affecting the reliability of the battery cell 1. As an example, the adhesive layer can be made of hot melt adhesive, the main component of which can be polypropylene or polyethylene. The first active material portion 311 can include graphite. The hot melt adhesive can have a high surface energy on the graphite surface and can uniformly cover the graphite surface. By setting the adhesive layer to be made of hot melt adhesive, the occurrence of powder shedding can be reduced, the risk of loss of active material of the first electrode 30 can be reduced, which is conducive to further improving the capacity of the battery cell 1 and further improving the reliability of the battery cell 1.

[0252] In the above technical solution, by setting the protective layer 70 as an adhesive layer, the adhesive layer can firmly adhere to the surface of the corresponding structural components within the battery cell 1. The protective layer 70 can provide durable protection for the corresponding structural components and can act as a buffer, reducing damage to the corresponding structural components. Furthermore, the protective layer 70 has good insulation properties, which can reduce the risk of leakage or short circuits in the corresponding structural components, further improving the reliability of the battery cell 1. When the protective layer 70 needs repair or replacement, the cost is low and the operation is simple. By setting the adhesive layer, the occurrence of powder shedding can be reduced, reducing the risk of loss of active material in the first electrode 30, which is conducive to further improving the capacity of the battery cell 1 and further enhancing its reliability.

[0253] According to some embodiments of this application, such as Figure 4As shown, the electrode assembly 20 also includes a second electrode 50 and a diaphragm 60. The first electrode 30 and the second electrode 50 are disposed opposite to each other. The diaphragm 60 is located between the first electrode 30 and the second electrode 50. The second electrode 50 includes a second current collector 51, a second active material layer 52 and an insulating layer 53. The second current collector 51 includes a current collector body portion 511 and a second protrusion extending from the current collector body portion 511 along a first direction. Along the thickness direction of the second current collector 51, the two surfaces of the current collector body portion 511 are provided with a second active material layer 52 and an insulating layer 53. The second active material layer 52 and the insulating layer 53 located on the same surface of the current collector body portion 511 are arranged along the first direction, and the second active material layer 52 is located on the side of the insulating layer 53 away from the second protrusion.

[0254] The first current collector 32 of the first electrode 30 may be provided with a second active material portion 312 and a first active material portion 311. The current collector body portion 511 of the second electrode 50 is provided with a second active material layer 52 and an insulating layer 53. By providing the first active material portion 311, an additional lithium-ion storage site can be provided for the battery cell 1, which helps to reduce the probability of lithium plating at the edge of the active material layer 31.

[0255] The first electrode 30 is the negative electrode, and the second electrode 50 is the positive electrode with the opposite polarity to the first electrode 30. The first electrode 30 and the second electrode 50 can be connected to the two electrode terminals 80 of the electrode assembly 20, thereby achieving the charging and discharging effect of the battery cell 1. The first electrode 30 and the second electrode 50 are arranged opposite to each other, and a separator 60 can be provided between the first electrode 30 and the second electrode 50. During the charging and discharging process of the battery cell 1, active ions (such as lithium ions) can be inserted and extracted back and forth between the first electrode 30 and the second electrode 50 through the separator 60. The separator 60 can reduce the risk of short circuit between the positive and negative electrodes.

[0256] The second electrode 50 may include a second current collector 51, a second active material layer 52, and an insulating layer 53. The second current collector 51 includes a current collector body 511 and a second protrusion, the second protrusion extending from the current collector body 511 along a first direction. The current collector body 511 and the second protrusion may be arranged along the first direction, and the second protrusion may be located above the current collector body 511. The current collector body 511 may be made of a material with good conductivity, such as metal foil, and the current collector body 511 can collect and conduct current during the charging and discharging process of the battery cell 1. The electrode assembly 20 may include a second conductive structure (not shown in the figure), and the second protrusion may be connected to the second conductive structure.

[0257] Along the thickness direction of the second current collector 51, the current collector body 511 has two opposing surfaces. Each surface of the current collector body 511 is provided with a second active material layer 52 and an insulating layer 53. The active material of the second active material layer 52 can be coated onto the corresponding surface, and the insulating layer 53 can be disposed on the corresponding surface of the current collector body 511. When the second electrode 50 is as... Figure 4 When setting the direction, the thickness direction of the second current collector 51 is... Figure 4 The insulating layer 53 can support the current collector body 511, reducing the risk of bending of the current collector body 511, thereby reducing the risk of cracking of the second current collector 51, and further reducing the risk of the second electrode 50 being affected by cracking of the second current collector 51, thus further improving the reliability of the battery cell 1. The second active material layer 52 and the insulating layer 53 located on the same surface of the current collector body 511 can be arranged along the first direction, and the second active material layer 52 is located on the side of the insulating layer 53 away from the second protrusion, and the second active material layer 52 can be located below the insulating layer 53.

[0258] In the above technical solution, by setting the second electrode 50 and the separator 60, the first electrode 30, the second electrode 50 and the separator 60 can cooperate to achieve the charging and discharging effect of the battery cell 1, which is conducive to further improving the reliability of the battery cell 1.

[0259] According to some embodiments of this application, such as Figure 4 As shown, along the first direction, the insulating layer 53 includes a first edge 531 and a second edge 532. The first edge 531 is further away from the second active material layer 52 than the second edge 532. The first conductive element 40 includes a third edge 43 close to the second active material portion 312. Along the direction from the first conductive element 40 to the second active material portion 312, the third edge 43 extends beyond the first edge 531 but does not extend beyond the second edge 532.

[0260] Among them, along the first direction, such as Figure 4As shown, the insulating layer 53 may include a first edge 531 and a second edge 532. The first edge 531 and the second edge 532 may be disposed opposite to each other and spaced apart along a first direction. The first edge 531 is further away from the second active material layer 52 than the second edge 532. The first edge 531 is located on the side of the insulating layer 53 away from the second active material layer 52. The first conductive element 40 includes a third edge 43. The third edge 43 is located on the side of the first conductive element 40 near the second active material portion 312. Along the direction from the first conductive element 40 to the second active material portion 312, the third edge 43 extends beyond the first edge 531 but does not extend beyond the second edge 532. That is, along the first direction, the setting height of the third edge 43 is higher than the setting height of the second edge 532 and lower than the setting height of the second edge 532. This can reduce the probability of short circuit between the second electrode 50 and the first electrode 30, which is beneficial to further reduce the risk of short circuit in the battery cell 1 and further improve the reliability of the battery cell 1.

[0261] As an example, the end of the second conductive structure facing the second current collector 51 can extend to the insulating layer 53, and the end of the second conductive structure facing the second current collector 51 can overlap with the insulating layer 53. Along the first direction, the overlap height between the end of the second conductive structure facing the second current collector 51 and the insulating layer 53 can be less than or equal to 0.5 mm, thereby reducing the risk of the second conductive structure and the first electrode 30 overlapping, further reducing the probability of short circuit in the battery cell 1, and helping to further improve the reliability of the battery cell 1.

[0262] In the above technical solution, by reasonably setting the relative positions of the insulating layer 53 and the first conductive element 40, the probability of the second electrode 50 contacting the first electrode 30 can be reduced, which is conducive to further reducing the risk of short circuit of the battery cell 1 and further improving the reliability of the battery cell 1.

[0263] According to some embodiments of this application, such as Figure 4 As shown, along the first direction, the end of the first active material portion 311 that is away from the second active material portion 312 extends beyond the second active material layer 52.

[0264] In this configuration, along the first direction, the height of the end of the first active material portion 311 facing away from the second active material portion 312 can be higher than the height of the upper end of the second active material layer 52. During the charging and discharging process of the battery cell 1, the active material on the first active material portion 311 typically undergoes volume changes. A higher first active material portion 311 provides more space for these volume changes, reducing the risk of structural damage to the first electrode 30 due to volume expansion, thereby further improving the stability of the battery cell 1. Furthermore, a higher first active material portion 311 can accommodate more lithium ions. When the battery cell 1 is overcharged, the first active material portion 311 can act as a buffer, reducing the risk of increased internal pressure and temperature in the battery cell 1. This helps reduce the possibility of thermal runaway and other safety issues in the battery cell 1, further improving its reliability.

[0265] In the above technical solution, by setting the end of the first active material part 311 that is away from the second active material part 312 along the first direction and extends beyond the second active material layer 52, the first active material part 311 can provide more space for the volume change of the active material, which can further improve the stability of the battery cell 1, and reduce the possibility of safety problems such as thermal runaway of the battery cell 1, which is more conducive to improving the reliability of the battery cell 1.

[0266] According to some embodiments of this application, the compacted density of the first active material portion 311 is greater than or equal to 1.3 g / cm³. 3 And less than or equal to 1.8 g / cm³ 3 .

[0267] The compaction density of the first active material portion 311 refers to the mass of active material contained in a unit volume after the active material in the first active material portion 311 is compacted under a certain pressure. When measuring the compaction density of the first active material portion 311, a first electrode 30 can be punched into a first circular piece with an area of ​​A. The weight M and thickness L of the first circular piece are measured. Another first electrode 30 is taken, and the first active material portion 311 on its surface is wiped off. This first electrode 30 is then punched into a second circular piece with an area of ​​A. The second circular piece M0 is weighed, and its thickness L0 is measured. The compaction density PD = (M - M0) / A × (L - L0).

[0268] The compaction density of the first active material part 311 is PD, which satisfies the relationship: 1.3 g / cm³. 3 ≤PD≤1.8g / cm 3 The compaction density of the first active material part 311 is expressed in g / cm³. 3 For example, the compaction density of the first active material portion 311 can be 1.3 g / cm³. 3 1.45g / cm3 1.6g / cm 3 1.8g / cm 3 The compacted density of the first active substance part 311 is 1.3 g / cm³. 3 Up to 1.8 g / cm 3 Within the specified range, all are optional compaction densities of the first active substance portion 311 in this application. The compaction density of the first active substance portion 311 is less than 1.3 g / cm³. 3 If the compaction density of the first active material portion 311 is low, the first active material portion 311 will be soft and unable to provide support for the first protrusion 3222. If the compaction density of the first active material portion 311 is greater than 1.8 g / cm³, then... 3 If the compaction density of the first active material portion 311 is too high, it will damage the first current collector 32, leading to a significant decrease in the elongation of the first electrode 30, making the first electrode 30 prone to cracking during subsequent discharge. Therefore, the compaction density of the first active material portion 311 should be around 1.3 g / cm³. 3 Up to 1.8 g / cm 3 In this configuration, the first active material portion 311 can support the first protrusion 3222, and the structure of the first current collector 32 can be stabilized, reducing the probability of cracking of the first electrode 30.

[0269] In the above technical solution, the compaction density of the first active material part 311 is set to be greater than or equal to 1.3 g / cm³. 3 And less than or equal to 1.8 g / cm³ 3 This not only enables the first active material part 311 to support the first protrusion 3222, but also stabilizes the structure of the first current collector 32 and reduces the probability of cracking of the first electrode 30.

[0270] According to some embodiments of this application, the binder content of the first active material portion 311 is greater than or equal to 1% and less than or equal to 5%.

[0271] The binder content of the first active material portion 311 refers to the percentage of the binder's mass to the total mass of the first active material portion 311. To measure the binder content of the first active material portion 311, the battery cell 1 can be disassembled, the first electrode 30 removed, and 10 mg of the first active material portion 311 powder scraped from the first electrode 30 can be tested using a thermogravimetric analyzer at a temperature range of 25-600℃ under a nitrogen atmosphere at a heating rate of 5℃ / min. The loss mass M1 of the first active material portion 311 powder can then be obtained, and the binder content of the first active material portion 311 is calculated as C = (M1 / 10) * 100%.

[0272] The binder content of the first active material portion 311 is C, satisfying the relationship: 1% ≤ C ≤ 5%. For example, the binder content of the first active material portion 311 can be 1%, 2%, 3.5%, 5%, etc., and any binder content within the range of 1% to 5% is acceptable; these are all selectable binder contents for the first active material portion 311 in this application. If the binder content of the first active material portion 311 is less than 1%, then the binder content of the first active material portion 311 is low, the cohesive force of the powder of the first active material portion 311 is low, the first active material portion 311 is loose, and the first active material portion 311 cannot provide support for the first protrusion 3222. If the binder content of the first active material portion 311 is greater than 5%, the excessive binder content will increase the resistance to electron transport within the first active material portion 311 due to the non-conductive nature of the binder, leading to increased impedance and energy loss. Furthermore, an excessively high binder content will occupy the pores and channels between the active material particles in the first active material portion 311, making the diffusion path of lithium ions longer and more tortuous, resulting in slower lithium ion migration during charging and discharging and reduced kinetic performance of the battery cell 1. Therefore, a binder content between 1% and 5% in the first active material portion 311 can improve its hardness, support the first protrusion 3222, and optimize the internal conductive network, thus improving the kinetic performance of the battery cell 1.

[0273] In the above technical solution, by setting the binder content of the first active material part 311 to be greater than or equal to 1% and less than or equal to 5%, the first active material part 311 can support the first protrusion 3222, and the conductive network inside the first active material part 31 can be made reasonable, which is beneficial to improving the dynamic performance of the battery cell 1.

[0274] According to some embodiments of this application, the active material layer 31 has a carbon-based material.

[0275] The active material layer 31 comprises a carbon-based material, which may include graphite and a conductive agent. Graphite provides suitable capacity, and the conductive agent provides a conductive network, thus enabling the first electrode 30 to meet capacity and conductivity requirements. By incorporating a carbon-based material into the active material layer 31, the first electrode 30 can meet capacity and conductivity requirements, further improving the electron transport efficiency of the active material layer 31. This helps reduce the resistance of the battery cell 1 during charging and discharging, further reducing energy loss and improving the charging and discharging efficiency of the battery cell 1. Furthermore, carbon-based materials possess high chemical stability, resisting corrosion and oxidation by the electrolyte, which further enhances the cycle life and reliability of the battery cell 1.

[0276] In the above technical solution, by setting the active material layer 31 to have a carbon-based material, the first electrode 30 can meet the capacity and conductivity requirements, which can further improve the electron transport efficiency of the active material layer 31, which is beneficial to reduce the resistance of the battery cell 1 during the charging and discharging process, further reduce energy loss, further improve the charging and discharging efficiency of the battery cell 1, and further improve the cycle life and reliability of the battery cell 1.

[0277] According to some embodiments of this application, the support substrate 321 is constructed as an insulating substrate.

[0278] The supporting substrate 321 can be insulating, and can be constructed as an insulating substrate. The insulating substrate can effectively isolate the first current collector 32 from other conductive components. The insulating substrate can reduce the risk of short circuits in the battery cell 1, reducing the occurrence of short circuits due to accidental contact during assembly or use. The insulating substrate can also reduce the self-discharge of the battery cell 1, decreasing the probability of disordered electron conduction in the non-charging / discharging state. This helps maintain the charge of the battery cell 1, further extending its storage time and lifespan, allowing the battery cell 1 to better maintain its performance during long-term storage or when not in use.

[0279] By setting the support substrate 321, it can be constructed as an insulating substrate. The first current collector 32 can be a composite current collector, which can be constructed as a composite structure of the support substrate 321 and the metal layer 322. The metal layer 322 has a small thickness, and the support substrate 321 can be made of lightweight materials, such as polymer films. Compared with a current collector constructed of pure metal, the amount of metal used in the first current collector 32 can be reduced, which is beneficial to reduce the weight of the first electrode 30, thereby reducing the weight of the battery cell 1 and increasing the energy density of the battery cell 1. Furthermore, in the event of puncture of the first current collector 32, the probability of the metal layer 322 overlapping with other components can be reduced, which can further reduce the short circuit risk of the battery cell 1 and further improve the reliability of the battery cell 1.

[0280] In the above technical solution, by setting the support substrate 321 as an insulating substrate and the first current collector 32 as a composite current collector, the weight of the battery cell 1 can be reduced, the risk of short circuit of the battery cell 1 can be reduced, and the self-discharge phenomenon of the battery cell 1 can be reduced. This is beneficial to maintaining the charge of the battery cell 1, and further extending the storage time and service life of the battery cell 1, so that the battery cell 1 can better maintain its performance when stored for a long time or not used.

[0281] According to some embodiments of this application, such as Figure 8As shown, the first conductive elements 40 located on both sides of the first current collector 32 can extend along the first direction. The two first conductive elements 40 can be arranged in parallel or approximately parallel. The lengths of the two first conductive elements 40 along the first direction can be equal. Both first conductive elements 40 can be connected to the electrode terminal 80 of the negative electrode. Both first conductive elements 40 can be used for conduction. Both first conductive elements 40 can be welded to the first protrusion 3222 of the corresponding metal layer 322 to form the first solder mark 91.

[0282] like Figure 8 As shown, in this embodiment, the height of the first solder mark 91 along the first direction can be H6, satisfying the relationship: 2mm ≤ H6 ≤ 3mm. For example, the height of the first solder mark 91 can be 2mm, 2.2mm, 2.7mm, 3mm, etc. The height of the first solder mark 91 can be within the range of 2mm to 3mm, including any value including the endpoint value; any value is an optional height of the first solder mark 91 in this application. If the height of the first solder mark 91 is less than 2mm, a poor solder joint will occur, and the current-carrying area between the first protrusion 3222 and the first connection portion will be too small, affecting the current-carrying capacity between the first connection portion and the first protrusion 3222. If the height of the first solder mark 91 is greater than 3mm, the space occupied by the first conductive element 40 will increase, reducing the energy density of the battery cell 1. Therefore, the height of the first solder mark 91 is between 2mm and 3mm, which can further enhance the current flow capacity between the first connection part and the first protrusion 3222, reduce the space occupied by the first conductive element 40, and further improve the energy density of the battery cell 1.

[0283] like Figure 9 As shown, when the two first conductive elements 40 are arranged in parallel and the length of the two first conductive elements 40 along the first direction is equal, the first connecting portion can extend to the first active material portion 311 from the first conductive element 40 to the first active material portion 311 to cover a portion of the first active material portion 311.

[0284] According to some embodiments of this application, in the production of battery cell 1, a first electrode 30, a second electrode 50, and a separator 60 can be fabricated separately, and then the first electrode 30, the second electrode 50, and the separator 60 are assembled together. In the fabrication of the first electrode 30, negative electrode active material (graphite), thickener (CMC), conductive agent (SP), and binder (SBR) are mixed uniformly in a certain mass ratio, and then deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode active slurry. The negative electrode active slurry is directly coated onto different substrates, and then cold-pressed, rolled, coated, slit, and die-cut to obtain the first electrode 30. In the fabrication of the second electrode 50, positive electrode active material (LFP), conductive agent (SP), and binder (PVDF) are mixed uniformly in a certain mass ratio, and then NMP is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode active slurry. The positive electrode active slurry was directly coated onto a 13µm aluminum foil, and then cold-pressed and die-cut to obtain the second electrode 50.

[0285] The second electrode 50, the separator 60, and the first electrode 30 are placed in sequence, with the separator 60 positioned between the positive and negative electrodes to provide isolation. The electrodes are then stacked to obtain the electrode assembly 20. The electrode assembly 20 is installed in the housing 10, electrolyte is injected, and the assembly is sealed to obtain the battery cell 1.

[0286] According to some embodiments of this application, such as Figure 2 As shown, this application also provides a battery device 110, including a battery cell 1 of any of the above embodiments.

[0287] The battery device 110 may include a housing 1101 and at least one battery cell 1. This embodiment uses multiple battery cells 1 as an example, where multiple battery cells 1 can be housed within the housing 1101. The housing 1101 may include a first housing portion 11011 and a second housing portion 11012. The first housing portion 11011 can be assembled with the second housing portion 11012, and the first housing portion 11011 and the second housing portion 11012 together define an assembly space 11013, within which multiple battery cells 1 can be installed. As an example, multiple battery cells 1 can be directly and fixedly connected to the housing 1101. As another example, multiple battery cells 1 can be bundled together with cable ties to form a battery module, which can be fixedly connected to the housing 1101.

[0288] In the above technical solution, using the battery cell 1 in the above embodiment can improve the reliability of the battery device 110 and extend the service life of the battery device 110.

[0289] According to some embodiments of this application, this application also provides an electrical device 100, including a battery device 110 of any of the above schemes.

[0290] The power-consuming device 100 can be any of the aforementioned devices using the battery device 110. Using the battery device 110 in the above embodiments can improve the reliability of the power-consuming device 100.

[0291] According to some embodiments of this application, such as Figures 2-6 As shown, the battery device 110 includes multiple battery cells 1 and a housing 1101. The multiple battery cells 1 are installed inside the housing 1101. The housing 1101 includes a first housing portion 11011 and a second housing portion 11012. The first housing portion 11011 and the second housing portion 11012 together define an assembly space 11013. The multiple battery cells 1 are installed inside the assembly space 11013. The battery cell 1 includes a housing 10 and an electrode assembly 20. The housing 10 may include a housing body 12 and an end cap 11. The housing body 12 and the end cap 11 are fitted together and together define the installation space 13. Electrode terminals 80 are disposed on the end cap 11, and the electrode assembly 20 is installed inside the installation space 13. The electrode assembly 20 includes a first electrode 30, a second electrode 50, a first conductive element 40, a second conductive structural element, and a diaphragm 60. The first electrode 30 is a negative electrode, and the second electrode 50 is a positive electrode with the opposite polarity to the first electrode 30. There are two electrode terminals 80, which are respectively connected to the first electrode 30 and the second electrode 50. The first electrode 30 includes a first current collector 32 and an active material layer 31. The first current collector 32 includes a supporting substrate 321 and two metal layers 322. Along the thickness direction of the first current collector 32, the two metal layers 322 are respectively disposed on opposite sides of the supporting substrate 321. The active material layer 31 is disposed on the side of the metal layer 322 facing away from the supporting substrate 321. The two active material layers 31 are respectively disposed on the side of the two metal layers 322 facing away from the supporting substrate 321. The active material layer 31 includes a first active material portion 311 and a second active material portion 312. First conductive elements 40 are provided on both sides of the first current collector 32. The first conductive elements 40 are connected to the metal layer 322 on the corresponding side. The first conductive elements 40 on both sides of the first current collector 32 are arranged opposite to each other.

[0292] The metal layer 322 includes a conductive main body 3221 and a plurality of first protrusions 3222. The plurality of first protrusions 3222 are arranged along the length direction of the first electrode 30. Each first protrusion 3222 has a corresponding first conductive element 40 connected thereto. Two first conductive elements 40 are arranged opposite each other along the thickness direction of the first current collector 32. The plurality of first conductive elements 40 are arranged along the length direction of the first electrode 30. The first conductive element 40 is located on the side of the second active material portion 312 facing the first protrusion 3222 and spaced apart from the second active material portion 312. The first conductive element 40 connects the first protrusion 3222 and the corresponding electrode terminal 80. Along the first direction, the first active material portion 311 is located between the second active material portion 312 and the first conductive element 40. The conductive main body 3221 is provided with the second active material portion 312, and the first protrusion 3222 is provided with the first active material portion 311. The first active material portion 311 and the second active material portion 312 are adjacent to each other. From the second active material portion 312 to the first conductive element 40, the thickness of the first active material portion 311 is smaller than the thickness of the second active material portion 312, and the longitudinal cross-section of the first active material portion 311 is trapezoidal. Along the first direction, the height of the first active material portion 311 can be 1 mm.

[0293] The first conductive element 40 has a first connecting portion, an extension portion 41, and a second connecting portion 42. The second connecting portion 42, the first connecting portion, and the extension portion 41 are arranged sequentially. The first connecting portion connects between the second connecting portion 42 and the extension portion 41. The extension portion 41 is located on the side of the first connecting portion facing the first active material portion 311. The first connecting portion is welded to the first protrusion 3222 to form a first solder mark 91. The two second connecting portions 42 of the two first conductive elements 40 are welded to form a second solder mark 92. The first electrode 30 also includes a protective layer 70, which is constructed as an adhesive layer. The first active material portion 311 and the first conductive element 40 are spaced apart along a first direction to form a first gap. The first solder mark portion 91 and the first active material portion 311 are spaced apart to form a second gap 33. The protective layer 70 extends to the first active material portion 311 to cover a portion of the first active material portion 311. The protective layer 70 completely fills the first gap and the second gap 33. The thickness dimension of the overlap between the protective layer 70 and the first active material portion 311 along the thickness direction of the first current collector 32 is less than or equal to the thickness dimension of the second active material portion 312.

[0294] Along the first direction, the protective layer 70 completely covers the first solder mark 91 and the second solder mark 92. Along the first direction, the height of the protective layer 70 covering the first active material part 311 can be 0.5 mm, the height of the first solder mark 91 can be 2 mm, and the spacing between the first solder mark 91 and the first active material part 311 can be 0.5 mm.

[0295] The first conductive elements 40 on both sides of the first current collector 32 are parallel to each other. From the first active material portion 311 to the first conductive element 40, each first conductive element 40 protrudes from the first protrusion 3222. The first conductive element 40 on one side of the first current collector 32 is bent towards the first conductive element 40 on the other side of the first current collector 32 and welded to the other first conductive element 40 to form a second solder mark 92. The second solder mark 92 is adjacent to the first solder mark 91 on the other first conductive element 40. The protective layer 70 completely covers the second solder mark 92. From the first active material portion 311 to the first conductive element 40, the outer end of the protective layer 70 protrudes from the outer end of the second solder mark 92. Along the first direction, the height of the second solder mark 92 can be 1 mm.

[0296] The first electrode 30 and the second electrode 50 are disposed opposite to each other, and the diaphragm 60 is located between the first electrode 30 and the second electrode 50. The second electrode 50 includes a second current collector 51, a second active material layer 52, and an insulating layer 53. The second current collector 51 includes a current collector body portion 511 and a second protrusion, which are arranged along a first direction, with the second protrusion located above the current collector body portion 511. The electrode assembly 20 may also include a second conductive structure, and the second protrusion is connected to the second conductive structure. Along the thickness direction of the second current collector 51, the second active material layer 52 and the insulating layer 53 are provided on both surfaces of the current collector body portion 511. Along the first direction, the insulating layer 53 includes a first edge 531 and a second edge 532. The first edge 531 is further away from the second active material layer 52 than the second edge 532. The first conductive element 40 includes a third edge 43 close to the second active material portion 312. Along the direction from the first conductive element 40 to the second active material portion 312, the third edge 43 extends beyond the first edge 531 but does not extend beyond the second edge 532.

[0297] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0298] 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, include: The outer casing is equipped with electrode terminals; An electrode assembly is disposed within the housing. The electrode assembly includes a first electrode sheet, which includes a first current collector and an active material layer. The first current collector includes a supporting substrate and a metal layer. The supporting substrate, the metal layer, and the active material layer are stacked along the thickness direction of the first current collector. The metal layer is at least partially located between the supporting substrate and the active material layer. The active material layer is disposed on the surface of the metal layer facing away from the supporting substrate. The metal layer includes a conductive body portion and a first protrusion extending from the conductive body portion along a first direction, the first direction being perpendicular to the thickness direction of the first current collector. The active material layer includes a first active material portion and a second active material portion, the second active material portion being disposed on the side surface of the conductive body portion away from the support substrate, and the first active material portion being disposed on the side surface of the first protrusion portion away from the support substrate.

2. The battery cell according to claim 1, characterized in that, The first active material portion and the second active material portion are adjacent to each other.

3. The battery cell according to claim 2, characterized in that, Along the first direction, the height of the first active material portion is greater than or equal to 0.5 mm and less than or equal to 2 mm.

4. The battery cell according to claim 1, characterized in that, Along the thickness direction of the first electrode, the thickness of the first active material portion is less than the thickness of the second active material portion.

5. The battery cell according to claim 4, characterized in that, From the second active material portion to the first active material portion, the thickness of the first active material portion gradually decreases.

6. The battery cell according to any one of claims 1-5, characterized in that, The electrode assembly further includes a first conductive element connected to the first protrusion. Along the first direction, the first active material portion is located between the second active material portion and the first conductive element. The first conductive element has a first connecting portion located on the side of the first protrusion away from the support substrate. The first connecting portion is welded to the first protrusion to form a first solder mark. The first active material portion and the first solder mark are spaced apart along the first direction to form a first gap between the first active material portion and the first solder mark.

7. The battery cell according to claim 6, characterized in that, The first electrode further includes a protective layer, at least a portion of which is located on the side of the first connecting portion opposite to the first protrusion and fixed to the first connecting portion, the protective layer covering the first solder mark portion.

8. The battery cell according to claim 7, characterized in that, The first conductive element includes an extension connected to the first connecting portion, the extension being located on the side of the first connecting portion near the second active material portion, at least a portion of the extension being located within the first gap, and the extension being not welded to the first protrusion.

9. The battery cell according to claim 8, characterized in that, From the first conductive element to the second active material portion, the extension portion and the first active material portion are spaced apart to form a second gap between the extension portion and the first active material portion, the protective layer covers the extension portion, and at least a portion of the protective layer is located in the second gap and fixed to the first protrusion portion.

10. The battery cell according to claim 9, characterized in that, The protective layer extends to the first active material portion to cover at least a portion of the first active material portion.

11. The battery cell according to claim 10, characterized in that, The protective layer covers a portion of the first active material portion, and the protective layer is spaced apart from the second active material portion.

12. The battery cell according to claim 11, characterized in that, Along the first direction, the height of the protective layer covering the first active material portion is greater than 0 mm and less than or equal to 1 mm.

13. The battery cell according to claim 11, characterized in that, The thickness of the overlapping portion of the protective layer and the first active material portion along the thickness direction of the first current collector is less than or equal to the thickness of the second active material portion.

14. The battery cell according to claim 8, characterized in that, From the direction from the first conductive element to the first active material portion, the extension extends to the first active material portion to cover a portion of the first active material portion.

15. The battery cell according to claim 14, characterized in that, Along the first direction, the height dimension of the extension covering the first active material portion is greater than 0 mm and less than or equal to 1 mm.

16. The battery cell according to claim 14, characterized in that, The thickness of the overlapping portion of the extension and the first active material portion along the thickness direction of the first current collector is less than or equal to the thickness of the second active material portion.

17. The battery cell according to claim 7, characterized in that, Along the first direction, the height of the first solder mark is greater than or equal to 1.5 mm and less than or equal to 3 mm.

18. The battery cell according to claim 7, characterized in that, Along the first direction, the distance between the first solder mark portion and the first active material portion is greater than or equal to 0.1 mm and less than or equal to 1 mm.

19. The battery cell according to claim 7, characterized in that, There are two metal layers and two active material layers. Along the thickness direction of the first current collector, the two metal layers are respectively disposed on opposite sides of the support substrate, and the two active material layers are respectively disposed on the side of the two metal layers away from the support substrate. The first conductive element is provided on both sides of the first current collector. The first conductive elements on both sides of the first current collector are disposed opposite to each other, and the first conductive element is connected to the metal layer on the corresponding side.

20. The battery cell according to claim 19, characterized in that, Along the first direction, the first conductive element includes a first connecting portion and a second connecting portion, the first connecting portion and the second connecting portion are connected, the second connecting portion protrudes from the first active material portion in the direction to the first conductive element from the first protrusion portion, the two second connecting portions are welded to form a second solder mark portion, and the protective layer covers at least a portion of the second solder mark portion.

21. The battery cell according to claim 20, characterized in that, Along the first direction, the second solder mark and the first solder mark are adjacent to each other.

22. The battery cell according to claim 20, characterized in that, Along the first direction, the height of the second solder mark is greater than or equal to 0.5 mm and less than or equal to 2 mm.

23. The battery cell according to claim 20, characterized in that, The protective layer completely covers the second solder mark.

24. The battery cell according to claim 6, characterized in that, The electrode assembly further includes a second electrode and a diaphragm. The first electrode and the second electrode are disposed opposite to each other, and the diaphragm is located between the first electrode and the second electrode. The second electrode includes a second current collector, a second active material layer, and an insulating layer. The second current collector includes a current collector body and a second protrusion extending from the current collector body along a first direction. Along the thickness direction of the second current collector, the second active material layer and the insulating layer are provided on both surfaces of the current collector body. The second active material layer and the insulating layer located on the same surface of the current collector body are arranged along the first direction, and the second active material layer is located on the side of the insulating layer opposite to the second protrusion.

25. The battery cell according to claim 24, characterized in that, Along the first direction, the insulating layer includes a first edge and a second edge, the first edge being further away from the second active material layer than the second edge, and the first conductive element includes a third edge close to the second active material portion. Along the direction from the first conductive element to the second active material portion, the third edge extends beyond the first edge but does not extend beyond the second edge.

26. The battery cell according to claim 24, characterized in that, Along the first direction, the end of the first active material portion that is away from the second active material portion extends beyond the second active material layer.

27. The battery cell according to any one of claims 1-5, characterized in that, The compacted density of the first active material portion is greater than or equal to 1.3 g / cm³. 3 And less than or equal to 1.8 g / cm 3 .

28. The battery cell according to any one of claims 1-5, characterized in that, The binder content of the first active material portion is greater than or equal to 1% and less than or equal to 5%.

29. The battery cell according to any one of claims 1-5, characterized in that, The supporting substrate is constructed as an insulating substrate.

30. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-29.

31. An electrical device, characterized in that, Includes the battery device according to claim 30.

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