Battery cell, battery device and electric device

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a single battery, a battery device and a power utilization device, the single battery comprises a shell and an electrode assembly, the shell contains an electrolyte, and the electrolyte contains lithium ions; the shell is provided with a positive electrode leading-out part; the electrode assembly comprises a positive plate, the positive plate comprises a positive current collector, a positive conductive member and a positive active material layer, the aluminum layer comprises a main body part and a connecting part, at least part of the main body part is covered with the positive active material layer, and the connecting part is not covered with the positive active material layer; the connecting part comprises a first connecting sub-part and a second connecting sub-part, the first connecting sub-part is connected between the main body part and the second connecting sub-part, and the positive conductive component is electrically connected to the surface, opposite to the supporting base body, of the second connecting sub-part; the positive plate further comprises a blocking piece, and the blocking piece covers at least part of the area of the surface, back to the supporting base body, of the first connector part.

Description

Technical Field

[0001] This application belongs to the field of battery technology, and in particular relates 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, etc.

[0003] During use, over-discharge of individual battery cells can easily lead to problems such as electrical sparking, combustion, and explosion, seriously affecting the reliability of individual battery cells. Therefore, improving the reliability of individual battery cells is an important research direction in the field of battery technology.

[0004] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Utility Model Content

[0005] The purpose of this application is to provide a battery cell, a battery device, and an electrical device that can improve the reliability of the battery cell.

[0006] The technical solution adopted in the embodiments of this application is:

[0007] In a first aspect, a battery cell is provided, comprising a casing and an electrode assembly: the casing contains an electrolyte having lithium ions; the casing is provided with a positive electrode lead-out portion; the electrode assembly includes a positive electrode sheet, the positive electrode sheet including a positive current collector, a positive conductive member, and a positive active material layer, the positive conductive member being electrically connected to the positive electrode lead-out portion; the positive current collector includes a connected support substrate and an aluminum layer, the support substrate, the aluminum layer, and the positive active material layer being stacked along the thickness direction of the positive current collector, the aluminum layer being located between the positive active material layer and the support substrate. The aluminum layer includes a main body and a connecting portion arranged and connected along a first direction. At least a portion of the main body is covered with a positive electrode active material layer, while the connecting portion is not covered with a positive electrode active material layer. The first direction is perpendicular to the thickness direction of the positive electrode current collector. The connecting portion includes a first connecting sub-part and a second connecting sub-part. The first connecting sub-part is connected between the main body and the second connecting sub-part. The positive electrode conductive member is electrically connected to the surface of the second connecting sub-part facing away from the supporting substrate. The positive electrode sheet also includes a blocking member that covers at least a portion of the surface of the first connecting sub-part facing away from the supporting substrate.

[0008] By adopting the technical solution of this embodiment, the second connecting part of the positive electrode conductive component electrically connects the positive electrode lead-out part and the positive electrode current collector part, thereby realizing the transmission of electrical energy; while the blocking member covers at least a portion of the surface of the first connecting part of the connecting part facing away from the supporting substrate, the blocking member can separate the lithium ions in the electrolyte from at least a portion of the first connecting part, prevent the lithium ions from contacting the first connecting part, increase the difficulty of lithium ions contacting the first connecting part, reduce the risk of the first connecting part forming Li-Al alloy, reduce the risk of the first connecting part pulverizing corrosion, reduce the risk of the connecting part being open-circuited, reduce the risk of thermal runaway of the battery cell under over-discharge conditions, and improve the reliability of the battery cell.

[0009] In some embodiments, the blocking element is an insulating component.

[0010] By adopting the technical solution of this embodiment, the blocking member has insulating properties, which can insulate the first connecting part from other components (e.g., negative electrode sheet, etc.), reduce the short circuit risk of the battery cell, and help improve the reliability of the battery cell.

[0011] In some embodiments, the insulating component includes at least one of PP, PET, or fiberglass.

[0012] By adopting the technical solution of this embodiment, on the one hand, the PP, PET, and glass fiber components have good insulation properties, reducing the short-circuit risk of the battery cell and preventing lithium ions from contacting the first connector, thus reducing the risk of Li-Al alloy formation in the first connector; on the other hand, the PP, PET, and glass fiber components have good corrosion resistance and can maintain a stable structural morphology in the electrolyte, thereby reliably preventing lithium ions from contacting the first connector, reducing the risk of Li-Al alloy formation in the first connector, lowering the risk of thermal runaway in the battery cell under over-discharge conditions, and improving the reliability of the battery cell.

[0013] In some embodiments, the electrode assembly includes a negative electrode and a separator, the separator being used to separate the positive electrode and the negative electrode, and the porosity of the separator being less than that of the separator.

[0014] By adopting the technical solution of this embodiment, lithium ions can pass through the pore channels in the barrier and come into contact with the first connector. The porosity of the barrier is less than that of the separator, making it more difficult for lithium ions to pass through the barrier than for them to pass through the separator. This effectively increases the difficulty for lithium ions to pass through the barrier and come into contact with the first connector, reduces the risk of Li-Al alloy formation in the first connector, lowers the risk of thermal runaway in the battery cell under over-discharge conditions, and improves the reliability of the battery cell.

[0015] In some embodiments, the porosity of the blocking element is less than or equal to 5%, and optionally, the porosity of the blocking element is less than or equal to 2%.

[0016] By adopting the technical solution of this embodiment, the porosity of the blocking component is small, making it difficult for lithium ions to pass through the blocking component. This reduces the risk of forming a Li-Al alloy in the first connector, lowers the risk of thermal runaway in the battery cell under over-discharge conditions, and improves the reliability of the battery cell.

[0017] In some embodiments, the resistivity of the blocking element is greater than or equal to 10. 12 Ω·cm, optionally, the resistivity of the blocking element is greater than or equal to 10 Ω·cm. 16 Ω·cm.

[0018] By adopting the technical solution of this embodiment, the blocking member has good insulation performance. The blocking member can better insulate the first connecting part and other components, reduce the risk of short circuit in the battery cell, and improve the reliability of the battery cell.

[0019] In some embodiments, the thickness of the blocking element is T1, wherein T1 ≥ 5 μm, and optionally, 8 μm ≤ T1 ≤ 18 μm.

[0020] By adopting the technical solution of this embodiment, the blocking member can effectively prevent lithium ions from passing through the blocking member, reduce the risk of lithium ions coming into contact with the first connector, reduce the risk of the first connector forming a Li-Al alloy, reduce the risk of thermal runaway of the battery cell under over-discharge conditions, and improve the reliability of the battery cell.

[0021] In some embodiments, the electrolyte is a liquid electrolyte, and the contact angle between the blocking member and the liquid electrolyte is greater than or equal to 70°; optionally, the contact angle between the blocking member and the liquid electrolyte is greater than or equal to 90°.

[0022] By adopting the technical solution of this embodiment, the liquid electrolyte is less likely to wet the blocking component, and lithium ions in the electrolyte are less likely to come into contact with the first connector through the blocking component, thereby reducing the risk of Li-Al alloy formation in the first connector, reducing the risk of thermal runaway of the battery cell under over-discharge conditions, and improving the reliability of the battery cell.

[0023] In some embodiments, the positive electrode conductive member and the positive electrode active material layer are spaced apart, and the blocking member covers at least a portion of the first connector located between the positive electrode conductive member and the positive electrode active material layer.

[0024] By adopting the technical solution of this embodiment, the first connector can be exposed through the gap between the positive electrode conductive member and the positive electrode active material layer, making it easier for lithium ions in the electrolyte to contact the first connector. The blocking member covers at least a portion of the exposed part of the first connector, which can prevent lithium ions in the electrolyte from contacting the exposed part of the first connector. This effectively reduces the risk of Li-Al alloy formation in the first connector, reduces the risk of thermal runaway of the battery cell under over-discharge conditions, and improves the reliability of the battery cell.

[0025] In some embodiments, along a first direction, the side of the blocking member facing away from the positive electrode conductive member covers the end of the positive electrode active material layer near the first connector.

[0026] By adopting the technical solution of this embodiment, the blocking member can cover the end of the positive electrode active material layer near the first connector. Due to the obstruction of the blocking member, lithium ions are less likely to pass through the end of the positive electrode active layer near the first connector and come into contact with the first connector, which reduces the risk of Li-Al alloy formation in the first connector, reduces the risk of thermal runaway of the battery cell under over-discharge conditions, and improves the reliability of the battery cell.

[0027] In some embodiments, the positive electrode active material layer includes a first active material portion and a second active material portion arranged along a first direction, the end of the second active material portion near the first connector portion is connected to the first active material portion, and the thickness of the first active material portion is less than the thickness of the second active material layer; the blocking member covers at least a portion of the surface of the first active material portion facing away from the main body portion, and the blocking member does not cover the surface of the second active material portion facing away from the main body portion.

[0028] By adopting the technical solution of this embodiment, during the forming process of the positive electrode sheet, the positive electrode active material layer can be rolled to compress the positive electrode active material layer; the setting of the first active material part can reduce the rolling pressure on the edge of the positive electrode active material layer, reducing the risk of edge cracking of the positive electrode active material layer; in addition, the blocking member can utilize the space on the side of the first active material part facing away from the main body, reducing the risk of the blocking member protruding from the surface of the second active material part facing away from the main body, and reducing the problem of edge bulging after the positive electrode sheet is wound.

[0029] In some embodiments, along the direction from the main body portion toward the positive electrode active material layer, the blocking member does not protrude from the surface of the second active material portion facing away from the main body portion.

[0030] By adopting the technical solution of this embodiment, the blocking member does not protrude from the surface of the second active material portion facing away from the main body portion, which can effectively reduce the problem of edge bulging after the positive electrode sheet is wound.

[0031] In some embodiments, along the first direction, the size of the portion of the barrier member covering the positive electrode active material layer is W, wherein 0.1mm≤W≤1mm, and optionally, 0.2mm≤W≤0.5mm.

[0032] By adopting the technical solution of this embodiment, the blocking member can cover the end of the positive electrode active material layer near the first connector. Due to the obstruction of the blocking member, lithium ions are less likely to pass through the end of the positive electrode active layer near the first connector and come into contact with the first connector, reducing the risk of Li-Al alloy formation in the first connector, reducing the risk of thermal runaway of the battery cell under over-discharge conditions, and improving the reliability of the battery cell. It can also reduce the space occupied by the blocking member and increase the energy density of the battery cell. Therefore, the reliability and energy density of the battery cell can be balanced.

[0033] In some embodiments, the blocking member is bonded to the end of the positive electrode active material layer near the first connector portion.

[0034] By adopting the technical solution of this embodiment, the blocking member is bonded to the positive electrode active material layer. On the one hand, the blocking member can be fixed so that it can stably prevent lithium ions from contacting the first connector. On the other hand, the bonding between the blocking member and the positive electrode active material layer can also prevent lithium ions from passing between the blocking member and the positive electrode active material layer and thus contacting the first connector. This reduces the risk of Li-Al alloy formation in the first connector, lowers the risk of thermal runaway of the battery cell under over-discharge conditions, and improves the reliability of the battery cell.

[0035] In some embodiments, the positive electrode sheet further includes an insulating member covering at least a portion of the surface of the first connector facing away from the support substrate, at least a portion of the insulating member being located between the positive electrode conductive member and the positive electrode active material layer, and the portion of the insulating member located between the positive electrode conductive member and the positive electrode active material layer being covered by a blocking member.

[0036] By adopting the technical solution of this embodiment, the insulating component can support the first connector, thereby reducing the risk of cracking in the first connector. Furthermore, the insulating component covers the portion of the first connector located between the positive conductive member and the positive active material layer, also achieving insulation in this area, reducing the short-circuit risk of the battery cell and improving its reliability. At the gap between the positive conductive member and the positive active material layer, the blocking component and the insulating component can form a double-layer structure, effectively preventing lithium ions from contacting the first connector, reducing the risk of Li-Al alloy formation in the first connector, lowering the risk of thermal runaway in the battery cell under over-discharge conditions, and improving the reliability of the battery cell.

[0037] In some embodiments, an insulating member covers the end of the positive electrode active material layer near the connection portion and forms a covering area, and a blocking member covers at least a portion of the surface of the covering area facing away from the aluminum layer.

[0038] By adopting the technical solution of this embodiment, the blocking member can prevent lithium ions from contacting the first connector through the covered area, reducing the risk of Li-Al alloy formation in the first connector, reducing the risk of thermal runaway of the battery cell under over-discharge conditions, and improving the reliability of the battery cell.

[0039] In some embodiments, along the direction from the connecting portion to the main body portion, the side of the blocking member facing away from the positive electrode conductive member protrudes from the edge of the covered area facing away from the positive electrode conductive member.

[0040] By adopting the technical solution of this embodiment, the blocking member can completely cover the coverage area, which can effectively prevent lithium ions from contacting the first connector through the coverage area, reduce the risk of the first connector forming a Li-Al alloy, reduce the risk of thermal runaway of the battery cell under over-discharge conditions, and improve the reliability of the battery cell.

[0041] In some embodiments, the positive electrode conductive member includes a first conductive portion and at least one second conductive portion, the first conductive portion being connected to the second conductive portion, and the first conductive portion being welded to the surface of the second connecting portion facing away from the support substrate to form a first solder mark.

[0042] By adopting the technical solution of this embodiment, the first conductive part of the positive electrode conductive component is welded to the second connecting part, and the electrical connection between the positive electrode conductive component and the second connecting part is simple and convenient to process and manufacture.

[0043] In some embodiments, along a first direction, the side of the barrier member facing away from the positive electrode active material layer covers at least a portion of the area of ​​the first solder mark.

[0044] By adopting the technical solution of this embodiment, the blocking component covering the first solder mark can block burrs, metal debris and other components on the first solder mark, reduce the short circuit risk of the battery cell and improve the reliability of the battery cell. In addition, the blocking component can also prevent lithium ions from moving to the first solder mark, reduce the risk of lithium ions moving to the first connector through the first solder mark, reduce the risk of Li-Al alloy forming in the first connector, reduce the risk of thermal runaway of the battery cell under over-discharge conditions, and improve the reliability of the battery cell.

[0045] In some embodiments, along the direction from the main body to the connection portion, the side of the blocking member facing away from the positive electrode active material layer protrudes beyond the portion of the first solder mark facing away from the positive electrode active material layer.

[0046] By adopting the technical solution of this embodiment, the blocking component can completely cover the first solder mark, which can effectively prevent lithium ions from contacting the first connector through the first solder mark, reduce the risk of Li-Al alloy formation in the first connector, reduce the risk of thermal runaway of the battery cell under over-discharge conditions, and improve the reliability of the battery cell.

[0047] In some embodiments, the blocking element is bonded to the first solder mark.

[0048] By adopting the technical solution of this embodiment, the blocking member is bonded to the first solder layer. On the one hand, the blocking member can be fixed, so that the blocking member can better prevent lithium ions from contacting the first connector. On the other hand, the blocking member and the first solder layer are bonded together, which can prevent lithium ions from passing between the blocking member and the first solder layer and thus contacting the first connector. This reduces the risk of Li-Al alloy formation in the first connector, lowers the risk of thermal runaway of the battery cell under over-discharge conditions, and improves the reliability of the battery cell.

[0049] In some embodiments, the connecting portion includes a base portion and at least one protrusion, the base portion being connected between the protrusion and the main body portion, the size of the protrusion being smaller than the size of the base portion along a second direction, the second direction being perpendicular to the first direction and the thickness direction of the positive electrode current collector; a first conductive portion is welded to at least one of the base portion and the protrusion to form a first solder mark; the portion of the connecting portion located between the first solder mark and the positive electrode active material layer forms a first connecting sub-portion, and the other portion of the connecting portion forms a second connecting sub-portion.

[0050] By adopting the technical solution of this embodiment, the welding method between the first conductive part and the connecting part is flexible and diverse, and can meet different usage requirements.

[0051] In some embodiments, the first solder mark includes a first solder mark portion, wherein the protrusion is welded to the first conductive portion to form the first solder mark portion.

[0052] By adopting the technical solution of this embodiment, the protrusion is welded to the first conductive part, which has a simple structure and is easy to process and manufacture.

[0053] In some embodiments, the protrusion includes a first protruding sub-part and a second protruding sub-part, the first protruding sub-part being connected between the base portion and the second protruding sub-part, the size of the second protruding sub-part being smaller than the size of the first protruding sub-part along a second direction, and at least one of the first protruding sub-part and the second protruding sub-part being welded to a first conductive portion.

[0054] By adopting the technical solution of this embodiment, along the second direction, the size of the second protruding sub-part is smaller than the size of the first protruding sub-part, and the size of the protruding part near the base part is large, which is beneficial to improving the current carrying capacity of the part of the protruding part near the base part and improving the current carrying capacity of the positive electrode sheet; in addition, along the second direction, the size of the second protruding sub-part is small, which is beneficial to reducing the space occupied by the protruding part and improving the energy density of the battery cell.

[0055] In some embodiments, the first solder mark includes a second solder mark portion, wherein the first conductive portion is soldered to the surface of the substrate portion facing away from the supporting substrate to form the second solder mark portion.

[0056] By adopting the technical solution of this embodiment, the first conductive part is welded to the base part. Along the second direction, the base part has a large size, which is beneficial to increase the welding area between the positive electrode conductive component and the connecting part, improve the current carrying capacity of the positive electrode sheet, and improve the reliability of the battery cell.

[0057] In some embodiments, along the second direction, the size of the main body is L1 and the size of the base is L2, wherein 0.8 ≤ L2 / L1 ≤ 1.

[0058] By adopting the technical solution of this embodiment, with the design of 0.8≤L2 / L1≤1, along the second direction, the size of the main body is equal to or not much different from the size of the base body. The larger size of the base body is beneficial to increasing the size of the base body and the welding area of ​​the first conductive part, thereby improving the current carrying capacity of the positive electrode sheet and improving the fast charging performance of the battery cell.

[0059] In some embodiments, along the second direction, the size of the second solder mark is L3 and the size of the base portion is L2, wherein 0.8 ≤ L3 / L2 ≤ 1.

[0060] By adopting the technical solution of this embodiment, with the design of 0.8≤L3 / L2≤1, along the second direction, the size of the second solder mark is equal to or not much different from the size of the base part, the welding area of ​​the base part and the first conductive part is large, the overcurrent capacity of the positive electrode sheet is good, and the fast charging performance of the battery cell is good.

[0061] In some embodiments, the first solder mark further includes a first solder mark portion, the first conductive portion includes a first conductive part and at least one second conductive part, the second conductive part is connected between the first conductive part and the second conductive part, the first conductive part is soldered to the surface of the base portion facing away from the supporting base to form the second solder mark portion, and the second conductive part is soldered to the surface of the protrusion facing away from the supporting base to form the first solder mark portion.

[0062] By adopting the technical solution of this embodiment, the protrusion and the base are simultaneously welded to the first conductive part, which increases the welding area between the positive electrode conductive component and the positive electrode current collector, which is beneficial to improving the current carrying capacity of the positive electrode sheet and improving the fast charging capability of the battery cell.

[0063] In some embodiments, the first solder mark and the second solder mark are directly connected.

[0064] By adopting the technical solution of this embodiment, the first solder mark and the second solder mark form a whole first solder mark, which is convenient for processing and manufacturing and helps to reduce the manufacturing cost of the positive electrode sheet.

[0065] In some embodiments, there are multiple protrusions, multiple second conductive parts, and multiple second conductive elements; along a second direction, multiple protrusions are spaced apart, multiple second conductive elements are spaced apart, and multiple second conductive parts are spaced apart; each second conductive element is connected to each other in a one-to-one correspondence; the first conductive element is continuously arranged along the second direction, multiple second conductive elements are connected to the edge of the first conductive element facing away from the base portion, each second conductive element is welded to each protrusion in a one-to-one correspondence, and multiple second conductive elements are electrically connected to the positive electrode lead-out portion.

[0066] By adopting the technical solution of this embodiment, the first conductive electronic part is continuously arranged along the second direction, and multiple second conductive electronic parts can be connected into a whole. The first conductive electronic part can provide good support for the second conductive electronic parts, which can reduce the risk of the second conductive part and the electrode sheet of the inserted electrode assembly when the second conductive part is bent, reduce the short circuit risk of the battery cell, and improve the reliability of the battery cell. In addition, the first conductive electronic part is larger in size along the second direction, which is conducive to increasing the welding area between the first conductive electronic part and the base part, which is conducive to improving the current carrying capacity of the positive electrode sheet, and improving the fast charging performance and reliability of the battery cell. Furthermore, the first conductive electronic part can be divided into multiple regions along the second direction according to the multiple second conductive electronic parts, and one region can correspond to one second conductive electronic part. Electrons in each region can be transferred to the positive electrode lead-out part through the corresponding second conductive electronic part, so that the electrons in the positive electrode current collector are transferred in regions. The electron transmission path from each region to the corresponding second conductive electronic part is short, which is conducive to reducing the electron transmission distance, reducing the overall resistance of the positive electrode sheet, and improving the fast charging performance and reliability of the battery cell.

[0067] In some embodiments, there are two aluminum layers, which are respectively connected to opposite sides of the support substrate along the thickness direction of the positive current collector; there are two positive conductive members, whose first conductive portions are respectively welded to the second connecting portions of the two aluminum layers to form two first solder marks; there are two positive active material layers, which respectively cover the main body of the two aluminum layers on the surface facing away from the support substrate; there are two blocking members, which respectively cover at least a portion of the first connecting portions of the two aluminum layers on the surface facing away from the support substrate.

[0068] By adopting the technical solution of this embodiment, both opposite sides of the positive current collector are covered with a layer of positive active material, which can increase the capacity of the active material on the positive electrode sheet, thus improving the capacity and energy density of the battery cell. The two blocking components can protect the first connecting parts of the two aluminum layers respectively, reducing the risk of Li-Al alloy formation, pulverization corrosion, and open circuit at the connection, and lowering the risk of thermal runaway in the battery cell under over-discharge conditions, thereby improving the reliability of the battery cell. In addition, the two positive conductive components can electrically connect the aluminum layers on both sides, thereby breaking the insulation limitation of the supporting substrate on the two aluminum layers, effectively improving the conductivity of the positive electrode sheet, improving the fast charging performance of the battery cell, reducing the heat generation of the battery cell, and improving the reliability of the battery cell.

[0069] In some embodiments, along the direction from the main body to the connection portion, the portion of the blocking member protruding from the base portion forms a blocking portion, and along the second direction, the blocking portion is located on one side of the second conductive portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the positive current collector.

[0070] By adopting the technical solution of this embodiment, the blocking part can block burrs, metal debris and other components at the edge of the base part away from the positive electrode active material layer, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0071] In some embodiments, the blocking portions of the two blocking members are abutted together.

[0072] By adopting the technical solution of this embodiment, after the blocking parts of the two blocking members are attached, they can wrap the burrs, metal debris and other parts on the edge of the base part, reduce the risk of metal debris falling off, reduce the short circuit risk of the battery cell, and improve the reliability of the battery cell.

[0073] In some embodiments, along the first direction, the second conductive portion is located on the side of the protrusion facing away from the base portion, and the second conductive portions of the two positive electrode conductive members are welded together to form a second solder mark.

[0074] By adopting the technical solution of this embodiment, the second conductive parts of the two positive electrode conductive components are welded together to form a whole, thereby breaking the insulation limitation of the supporting substrate and facilitating connection with the positive electrode lead-out part.

[0075] In some embodiments, the blocking element covers at least a portion of the second solder mark.

[0076] By adopting the technical solution of this embodiment, the blocking component can cover the second solder mark, blocking sharp protrusions, metal debris and other components on the second solder mark, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0077] In some embodiments, the thickness of the connecting portion is T2, wherein 0.1μm≤T2≤2μm, and optionally, 0.5μm≤T2≤1.5μm.

[0078] By adopting the technical solution of this embodiment, the thickness of the connecting portion is reduced. A thinner connecting portion helps reduce the weight and cost of the positive electrode current collector, while also increasing the energy density of the battery cell. However, a thinner connecting portion results in poorer current carrying capacity and more severe heat generation. Consequently, in the event of over-discharge of the battery cell, the lithium intercalation potential is higher, increasing the risk of thermal runaway. The blocking component of this embodiment can prevent lithium ions from intercalating into the first connecting portion, reducing the risk of Li-Al alloy formation, reducing the risk of pulverization and corrosion of the first connecting portion, reducing the risk of open circuit in the connecting portion, and lowering the risk of thermal runaway in the battery cell under over-discharge conditions, thus improving the reliability of the battery cell. Therefore, both the reliability and energy density of the battery cell can be simultaneously considered.

[0079] In some embodiments, the thickness of the connecting portion is greater than at least a portion of the thickness of the main body portion.

[0080] By adopting the technical solution of this embodiment, the thickness of the connecting part is large, and the current carrying capacity of the connecting part is good, which is beneficial to improving the current carrying capacity of the positive electrode sheet. In addition, the large thickness of the connecting part results in a low lithium intercalation potential when the battery cell is over-discharged, which helps to reduce the risk of Li-Al alloy formation in the first connecting part, the risk of powdering corrosion in the first connecting part, the risk of open circuit in the connecting part, and the risk of thermal runaway in the battery cell under over-discharge conditions, thereby improving the reliability of the battery cell.

[0081] In some embodiments, the positive electrode includes a conductive protective layer, at least a portion of which is located between the positive electrode active material layer and the main body.

[0082] By adopting the technical solution of this embodiment, the conductive protective layer can play a buffering and lubricating role between the positive electrode active material layer and the main body, which can alleviate the damage to the main body caused by particles in the positive electrode active material layer during the rolling process of the positive electrode sheet, and is conducive to improving the conductivity of the main body and improving the current carrying capacity of the positive electrode sheet.

[0083] In some embodiments, the support substrate is an insulating substrate.

[0084] By adopting the technical solution of this embodiment, the support substrate is made of insulating material, which can reduce internal short circuits caused by puncture, reduce the probability of internal short circuits in battery cells, and improve the reliability of battery cells.

[0085] Secondly, a battery device is provided, comprising a plurality of the aforementioned battery cells.

[0086] The battery device of this application embodiment uses the above-mentioned battery cell, and the reliability of the battery cell is beneficial to improving the reliability of the battery device.

[0087] Thirdly, an electrical device is provided, comprising the aforementioned battery cell or battery device, wherein the battery cell or battery device is used to store or provide electrical energy.

[0088] The electrical device in this application uses the aforementioned battery cell and battery device, which improves the reliability of the electrical device.

[0089] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0090] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0091] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0092] Figure 2 This is a schematic diagram of the structure of a battery device provided in some embodiments of this application.

[0093] Figure 3 The diagram shows the structure of a single battery cell provided in some embodiments of this application.

[0094] Figure 4 Cross-sectional view of an electrode assembly provided in some embodiments of this application.

[0095] Figure 5 For along Figure 4 Sectional view along line AA in the middle.

[0096] Figure 6 This is a schematic diagram of the positive electrode sheet in an unfolded state, provided in some embodiments of this application.

[0097] Figure 7 For along Figure 6 Sectional view along the middle BB line.

[0098] Figure 8 For other embodiments of this application, the positive electrode sheet is provided along... Figure 6 Sectional view along the middle BB line.

[0099] Figure 9 This is a schematic diagram of the structure of the positive electrode sheet in the unfolded state after the hidden blocking member is provided in some embodiments of this application.

[0100] Figure 10 For along Figure 9 A magnified view of a section at point D.

[0101] Figure 11 for Figure 9 The diagram shows the structure of the positive electrode plate after concealing the insulating component and the positive electrode conductive component.

[0102] Figure 12 For along Figure 11 A magnified view of a section at point E in the middle.

[0103] Figure 13 This is a schematic diagram of the structure of the positive electrode sheet in the unfolded state after the hidden blocking member is provided in some embodiments of this application.

[0104] Figure 14 For along Figure 13 A magnified view of a section at point F.

[0105] Figure 15 for Figure 13 The diagram shows the structure of the positive electrode plate after concealing the insulating component and the positive electrode conductive component.

[0106] Figure 16 For along Figure 15 A magnified view of a section at point G.

[0107] Figure 17 For along Figure 6 Sectional view of the CC line.

[0108] The following are the labeling elements in the figure:

[0109] 1000, Vehicle; 1100, Battery Unit; 1200, Controller; 1300, Motor; 100, Battery Cell; 10, Electrode Assembly; 1, Positive Electrode Sheet; 11, Positive Electrode Current Collector; 111, Supporting Substrate; 112, Aluminum Layer; 1121, Main Body; 11211, First Part; 11212, Second Part; 11213, Third Part; 1122, Connecting Part; 11221, First Connecting Sub-part; 11222, Second Connecting Sub-part; 1131, Substrate; 1132, Protrusion; 11321, First Protruding Sub-part; 11322, Second Protruding Sub-part; 12, Positive Electrode Active Material Layer; 121, First Active Material Part; 122, Second Active Material 13. Positive electrode conductive component; 131. First conductive part; 1311. First conductive sub-part; 1312. Second conductive sub-part; 132. Second conductive part; 14. Conductive protective layer; 2. Negative electrode sheet; 21. Negative electrode current collector; 22. Negative electrode active material layer; 3. Isolator; 41. First solder mark; 411. First solder mark part; 412. Second solder mark part; 42. Second solder mark; 51. Blocking component; 511. Blocking part; 52. Insulating component; 60. Covering area; 20. Outer shell; 201. End cap; 2011. Positive electrode lead-out part; 2012. Negative electrode lead-out part; 202. Shell; 300. Box body; 301. First box body part; 302. Second box body part. Detailed Implementation

[0110] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0111] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0112] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0113] In this document, the term "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 throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments in any suitable manner.

[0114] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0115] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "Several" means one or more, unless otherwise explicitly specified.

[0116] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0117] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0118] In the description of the embodiments of this application, unless otherwise expressly specified and limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it may be directly connected to or indirectly connected to the other element.

[0119] 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.

[0120] In this application, "multiple" means two or more (including two).

[0121] A single battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0122] A battery device can refer to a single physical module that includes one or more battery cells to provide higher voltage and capacity.

[0123] A single battery cell typically includes an electrode assembly and a housing for containing the electrode assembly. The electrode assembly typically includes a positive electrode, a negative electrode, and a separator that separates the positive and negative electrodes.

[0124] During use, individual battery cells may experience over-discharge (i.e., the battery cell continues to discharge at a voltage below the preset lower limit of operation). Over-discharge can cause thermal runaway problems such as electrical sparking, combustion, and explosion, seriously affecting the reliability of the battery cell. In particular, the thermal runaway problem is especially prominent in high-energy-density battery cells.

[0125] In some battery cells, the positive electrode sheet includes a positive current collector, a positive conductive component, and a positive active material layer. The positive current collector includes a connected support substrate and an aluminum layer. The support substrate, aluminum layer, and positive active material layer are stacked along the thickness direction of the positive current collector, with the aluminum layer located between the support substrate and the positive active material layer. The support substrate provides good mechanical strength to the positive current collector, thereby reducing the thickness of the aluminum layer and increasing the capacity of the positive active material corresponding to the aluminum layer in the cell volume. This achieves high energy density in the battery cell and extends the driving time of the device. However, in actual use, over-discharge during battery cell operation is a contributing factor to thermal runaway in the battery cell.

[0126] The aluminum layer includes a main body and a connecting part connected to each other. The surface of the main body is covered with a positive electrode active material layer. The connecting part includes a first connecting part and a second connecting part. The first connecting part is connected between the second connecting part and the main body. The positive electrode conductive component is electrically connected to the second connecting part. Because the positive electrode conductive component has good conductivity, the second connecting part has good current carrying capacity. However, the first connecting part is relatively thin, resulting in poor current carrying capacity and easy heat generation.

[0127] In battery devices, due to manufacturing process deviations or the influence of factors such as the battery cell's operating environment, some battery cells exhibit inconsistencies. If the voltage of any one battery cell cannot be effectively monitored by the battery management system, these cells are at risk of over-discharge. When battery cells are connected in series, if one or more cells experience over-discharge, these cells will also be forced to over-discharge by the other cells. Under over-discharge conditions, the positive electrode potential of the battery cell will gradually decrease. When the positive electrode potential is lower than the lithium intercalation potential of aluminum, lithium ions released from the electrolyte are easily embedded in the first connector to form a Li-Al alloy (lithium-aluminum alloy), leading to the destruction of the structure of the first connector and even the failure of the positive electrode current collector.

[0128] Especially with thinner aluminum layers, when a battery cell is over-discharged, the first connector has poor current-carrying capacity and high temperature. The first connector is prone to reacting with lithium ions to form a Li-Al alloy, reducing its resistance to lithium-ion intercalation and increasing its lithium intercalation potential. This makes it easier for the positive electrode potential to reach the lithium intercalation potential. The formed Li-Al alloy easily causes the first connector to pulverize and corrode, damaging the aluminum layer structure and even causing the first connector to break and lose its current-carrying capacity, forming a partial open circuit. After the open circuit, the high voltage of the external battery cells will be applied to the open circuit point, which may cause the battery cell to have reverse voltage (i.e., the positive electrode potential is negative). The reverse voltage can even reach -30V or higher, causing the battery cell temperature to rise abnormally. In some cases, reverse high voltage may ignite the internal electrode plates, electrolyte, and other components of the battery cell, causing the battery cell to catch fire and explode, seriously affecting the reliability of the battery cell.

[0129] Based on this, this application provides a battery cell in which at least a portion of the surface of the first connector of the positive electrode sheet facing away from the supporting substrate is covered with a blocking element. The blocking element can prevent lithium ions from contacting the first connector, increasing the difficulty of lithium ions contacting the first connector, reducing the risk of Li-Al alloy formation in the first connector, reducing the risk of powdering corrosion in the first connector, reducing the risk of open circuit in the connector, reducing the risk of thermal runaway in the battery cell under over-discharge conditions, and improving the reliability of the battery cell.

[0130] The battery cells described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0131] The battery device disclosed in this application can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. 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. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0132] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0133] like Figure 1 As shown, a battery device 1100 is installed inside the vehicle 1000. The battery device 1100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 1100 can be used to power the vehicle 1000; for example, the battery device 1100 can serve as the operating power source for the vehicle 1000.

[0134] The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0135] In some embodiments of this application, the battery device 1100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0136] like Figure 2 As shown, the battery device 1100 includes a housing 300 and a battery cell 100. The housing 300 is used to house the battery cell 100, and the housing 300 can have various structures.

[0137] In some embodiments, the housing 300 may include a first housing portion 301 and a second housing portion 302, which overlap each other, and together define a receiving space for accommodating the battery cell 100. The second housing portion 302 may be a hollow structure with one open end, and the first housing portion 301 may be a plate-like structure, covering the open side of the second housing portion 302 to form a housing 300 with a receiving space. Alternatively, both the first housing portion 301 and the second housing portion 302 may be hollow structures with one open side, with the open side of the first housing portion 301 covering the open side of the second housing portion 302 to form a housing 300 with a receiving space. Of course, the first housing portion 301 and the second housing portion 302 may be of various shapes, such as cylinders, cuboids, etc.

[0138] To improve the sealing performance after the first housing part 301 and the second housing part 302 are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 301 and the second housing part 302.

[0139] Assuming that the first box part 301 covers the top of the second box part 302, the first box part 301 can also be called the upper box cover, and the second box part 302 can also be called the lower box.

[0140] In the battery device 1100, there can be one or more battery cells 100. If there are multiple battery cells 100, they can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 100 are connected in both series and parallel.

[0141] Multiple battery cells 100 can be directly connected in series, parallel, or in a mixed manner, and then the whole composed of multiple battery cells 100 can be housed in the housing 300; of course, multiple battery cells 100 can also be connected in series, parallel, or in a mixed manner to form a battery module, and multiple battery modules can then be connected in series, parallel, or in a mixed manner to form a whole, and housed in the housing 300.

[0142] For example, the battery cell 100 may be the smallest unit that makes up the battery device 1100.

[0143] like Figures 3-5 As shown, in some embodiments, the battery cell 100 includes a housing 20 and an electrode assembly 10, at least a portion of which is housed within the housing 20.

[0144] The outer shell 20 may be a hollow structure, with an internal space for accommodating the electrode assembly 10 and the electrolyte.

[0145] In some embodiments, the housing 20 includes a housing 202 and an end cap 201, the housing 202 having an opening and the end cap 201 for closing the opening.

[0146] The housing 202 is a component used to cooperate with the end cap 201 to form an internal cavity of the battery cell 100. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0147] The housing 202 and the end cap 201 can be separate components. For example, an opening can be provided on the housing 202, and the end cap 201 can be used to close the opening to form an internal cavity of the battery cell 100.

[0148] The housing 202 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 202 can be determined according to the specific shape and size of the electrode assembly 10. The housing 202 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0149] The shape of the end cap 201 can be adapted to the shape of the housing 202 to fit the housing 202. The material of the end cap 201 can be the same as or different from the material of the housing 202. Optionally, the end cap 201 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 201 is not easily deformed when subjected to compression and impact, so that the battery cell 100 can have higher structural strength and improve reliability.

[0150] The end cap 201 is connected to the housing 202 by welding, bonding, snap-fitting or other means.

[0151] The housing 202 may be open at one end or open at both ends. In some examples, the housing 202 may be a structure with an opening on one side, with one end cap 201 covering the housing 202. In other examples, the housing 202 may be a structure with openings on both sides, with two end caps 201 covering the two openings of the housing 202 respectively.

[0152] In some embodiments, the electrode assembly 10 is a component in the battery cell 100 where an electrochemical reaction occurs. The electrode assembly 10 may be entirely housed within the housing 20 or partially housed within the housing 20. For example, a portion of the tabs of the electrode assembly 10 may extend outside the housing 20.

[0153] Optionally, the electrode assembly 10 is entirely housed within the housing 20.

[0154] In some embodiments, the electrode assembly 10 includes a positive electrode 1 and a negative electrode 2. During the charging and discharging process of the battery cell 100, lithium ions are inserted and extracted back and forth between the positive electrode 1 and the negative electrode 2.

[0155] In some embodiments, the positive electrode 1 may include a positive current collector 11 and a positive active material layer 12 disposed on at least one surface of the positive current collector 11.

[0156] As an example, the positive current collector 11 has two surfaces opposite each other in its own thickness direction, and the positive active material layer 12 is disposed on either or both of the two opposite surfaces of the positive current collector 11.

[0157] As an example, the positive current collector 11 may be a composite current collector. The composite current collector may include a polymer material substrate and an aluminum layer 112. The composite current collector may be formed by coating aluminum or an aluminum alloy onto the surface of a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0158] As an example, the positive electrode active material layer 12 includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to 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, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0159] In some embodiments, the negative electrode 2 may include a negative electrode current collector 21 and a negative electrode active material layer 22 disposed on at least one surface of the negative electrode current collector 21.

[0160] As an example, the negative electrode current collector 21 has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer 22 is disposed on either or both of the two opposite surfaces of the negative electrode current collector 21.

[0161] As an example, the negative electrode current collector 21 can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloy, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper 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.).

[0162] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 100. As an example, the negative electrode active material may 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 may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cell 100 may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0163] In some embodiments, the negative electrode current collector 21 may be made of copper.

[0164] In some embodiments, the electrode assembly 10 further includes a separator 3 disposed between the positive electrode 1 and the negative electrode 2. The separator 3 serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0165] In some embodiments, the separator 3 is a separator membrane. The separator membrane in this application can be any known porous structure separator membrane with good chemical and mechanical stability.

[0166] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different. The separator 3 can be a separate component located between the positive electrode 1 and the negative electrode 2, or it can be attached to the surface of the positive electrode 1 or the surface of the negative electrode 2. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0167] In some embodiments, the battery cell 100 further includes an electrolyte that acts as a conductor of ions between the positive electrode 1 and the negative electrode 2. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0168] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0169] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0170] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0171] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell 100, such as additives that improve the overcharge / fast charge performance of the battery cell 100, additives that improve the high-temperature performance of the battery cell 100, additives that improve the low-temperature performance of the battery cell 100, etc.

[0172] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0173] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0174] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0175] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0176] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0177] In some embodiments, the separator 3 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode 1 and the negative electrode 2, and serves to both transport ions and isolate the positive and negative electrodes.

[0178] In some embodiments, the electrode assembly 10 is a wound structure. Exemplarily, both the positive electrode 1 and the negative electrode 2 are strip structures, and the positive electrode 1, the separator 3, and the negative electrode 2 are wound into a wound structure.

[0179] In some embodiments, the electrode assembly 10 has a stacked structure.

[0180] As an example, multiple positive electrode plates 1 and multiple negative electrode plates 2 can be set, and multiple positive electrode plates 1 and multiple negative electrode plates 2 can be stacked alternately.

[0181] As an example, multiple positive electrode plates 1 can be provided, and negative electrode plates 2 can be folded to form multiple stacked folded segments, with a positive electrode plate 1 sandwiched between adjacent folded segments.

[0182] As an example, both the positive electrode 1 and the negative electrode 2 are folded to form multiple stacked folded segments.

[0183] As an example, multiple separators 3 can be provided, each disposed between any adjacent positive electrode 1 or negative electrode 2.

[0184] As an example, the separator 3 can be continuously arranged between any adjacent positive electrode 1 or negative electrode 2 by folding or rolling.

[0185] In some embodiments, the electrode assembly 10 may be cylindrical, flat, or polygonal, etc.

[0186] In some embodiments, the battery cell 100 includes an electrode lead. The electrode lead is used to connect to an external circuit to enable charging or discharging of the battery cell 100. Exemplarily, when multiple battery cells 100 are assembled into a group, the electrode lead is used to connect to a busbar component.

[0187] There are two electrode leads, which are insulated from each other. The two electrode leads are a positive electrode lead 2011 and a negative electrode lead 2012. The positive electrode lead 2011 is electrically connected to the positive electrode plate 1, and the negative electrode lead 2012 is electrically connected to the negative electrode plate 2, so as to output or input electrical energy of the battery cell 100.

[0188] In some examples, the electrode leads can be electrode terminals disposed on the housing 20. The electrode terminals are formed independently of the housing 20 and are assembled together during the production process of the battery cell 100. As an example, the electrode terminals are insulatedly disposed on the end cap 201 or the housing 202.

[0189] In some examples, the electrode lead-out may also be part of the housing 20. For example, the electrode lead-out may be the end cap 201 of the housing 20, or the electrode lead-out may be the end wall of the housing 202 opposite to the end cap 201.

[0190] See Figure 6 and Figure 7As shown, in some embodiments, the battery cell 100 includes a casing 20 and an electrode assembly 10; the casing 20 contains an electrolyte having lithium ions; the casing 20 is provided with a positive electrode lead-out portion 2011; the electrode assembly 10 includes a positive electrode sheet 1, the positive electrode sheet 1 includes a positive electrode current collector 11, a positive electrode conductive member 13, and a positive electrode active material layer 12, the positive electrode conductive member 13 being electrically connected to the positive electrode lead-out portion 2011; the positive electrode current collector 11 includes a connected support substrate 111 and an aluminum layer 112, the support substrate 111, the aluminum layer 112, and the positive electrode active material layer 12 being stacked along the thickness direction of the positive electrode current collector 11, the aluminum layer 112 being located between the positive electrode active material layer 12 and the support substrate 111; the aluminum layer 112 includes a first direction The main body 1121 and the connecting part 1122 are arranged and connected to each other. At least a portion of the main body 1121 is covered with a positive electrode active material layer 12, while the connecting part 1122 is not covered with the positive electrode active material layer 12. The first direction is perpendicular to the thickness direction of the positive electrode current collector 11. The connecting part 1122 includes a first connecting sub-part 11221 and a second connecting sub-part 11222. The first connecting sub-part 11221 is connected between the main body 1121 and the second connecting sub-part 11222. The positive electrode conductive member 13 is electrically connected to the surface of the second connecting sub-part 11222 facing away from the supporting substrate 111. The positive electrode sheet 1 also includes a blocking member 51, which covers at least a portion of the surface of the first connecting sub-part 11221 facing away from the supporting substrate 111.

[0191] The electrolyte contains lithium ions. This can be understood as lithium ions contained in the electrolyte itself, or lithium ions extracted from the positive electrode active material layer 12, or lithium ions extracted from the negative electrode active material layer 22, entering the electrolyte.

[0192] The positive electrode conductive component 13 can refer to a component used for electrically connecting the positive electrode lead-out portion 2011 and the positive electrode current collector 11. For example, the positive electrode conductive component 13 can be made of aluminum foil, which has good conductivity, which is beneficial to improving the overcurrent capacity between the positive electrode current collector 11 and the positive electrode lead-out portion 2011, and is beneficial to improving the fast charging performance of the battery cell 100. Of course, in other examples, the positive electrode conductive component 13 can also be made of other materials with good conductivity.

[0193] In some examples, the positive electrode lead-out portion 2011 can be directly connected to the positive conductive member 13; for example, the positive electrode lead-out portion 2011 is directly soldered to the positive conductive member 13.

[0194] In some examples, the positive electrode lead-out portion 2011 can be connected to the positive electrode conductive member 13 by a conductive element (e.g., an adapter plate, a current collector, etc.). For example, one side of the conductive element is welded to the positive electrode conductive member 13, and the other side of the conductive element is welded to the positive electrode lead-out portion 2011.

[0195] The support substrate 111 serves to support the aluminum layer 112. The support substrate 111 can be made of conductive material, which can improve the conductivity of the positive current collector 11 and help improve the fast charging capability of the battery cell 100.

[0196] The support substrate 111 can be made of insulating material. For example, the positive electrode current collector 11 is a composite current collector, and the polymer material substrate of the composite current collector forms the support substrate 111. The aluminum layer 112 can refer to a layer of aluminum or aluminum alloy material formed on the surface of the insulating substrate. The aluminum layer 112 is provided on one side of the support substrate 111 along its own thickness direction, or the aluminum layer 112 is provided on two opposite sides of the support substrate 111 along its own thickness direction. The positive electrode active material layer 12 is located on the side of the aluminum layer 112 facing away from the support substrate 111, so that the support substrate 111, the aluminum layer 112 and the positive electrode active material layer 12 are stacked along the thickness direction of the positive electrode current collector 11, and the aluminum layer 112 is located between the support substrate 111 and the positive electrode active material layer 12.

[0197] The aluminum layer 112 includes a main body 1121 and a connecting portion 1122. The aluminum layer 112 is divided into two parts along a first direction: one part is the main body 1121, and the other part is the connecting portion 1122. A portion of the main body 1121 is covered with the positive electrode active material layer 12, or the entire main body 1121 is covered with the positive electrode active material layer 12, while the connecting portion 1122 is not covered with the positive electrode active material layer 12. The main body 1121 and the connecting portion 1122 are separated by the end face of the positive electrode active material layer 12 near the connecting portion 1122. It should be noted that the portion of the positive electrode conductive member 13 and the positive electrode current collector 11 not covered with the positive electrode active material layer 12 together form the tab of the positive electrode sheet 1.

[0198] The positive electrode active material layer 12 can be directly covered on the surface of the main body 1121 facing away from the supporting substrate 111. Other conductive structures can also be provided between the positive electrode active material layer 12 and the main body 1121. For example, the conductive structure can be formed by mixing a conductive agent and a binder. The binder bonds the positive electrode active material layer 12 and the main body 1121, while the conductive agent is responsible for conducting electrons. The conductive agent can be carbon black, graphite, etc., and the binder can be polyvinylidene fluoride, etc.

[0199] The first direction can refer to the direction perpendicular to the thickness direction of the positive electrode current collector 11; the second direction can refer to the direction perpendicular to both the thickness direction of the positive electrode current collector 11 and the first direction.

[0200] In some examples, the electrode assembly 10 has a wound structure, and when the positive electrode 1 is in the unfolded state, the first direction can be referred to as the width direction of the positive electrode 1 (see reference). Figure 6The thickness direction of the positive electrode current collector 11 can be found in the thickness direction of the positive electrode sheet 1 (see Z direction in the original text). Figure 7 (Y direction in the text); the second direction can be referred to the length direction of positive electrode 1 (see also...). Figure 6 (Central X direction). When the positive electrode 1 is in a wound state, the second direction can also be referred to the winding direction of the positive electrode 1 (see reference). Figure 4 (The direction indicated by the middle arrow V).

[0201] In some examples, the electrode assembly 10 is a stacked structure, and the first direction can be the width direction of the positive electrode 1 (see reference). Figure 6 (Z direction in the text), the second direction can be referred to the length direction of positive electrode 1 (see also...) Figure 6 (in the X direction).

[0202] With the positive electrode plate 1 in its unfolded state, the connecting portion 1122 is divided into two parts along the first direction. The part closer to the main body portion 1121 is the first connecting sub-part 11221, and the part farther from the main body portion 1121 is the second connecting sub-part 11222. The positive electrode conductive member 13 is electrically connected to the surface of the second connecting sub-part 11222 facing away from the supporting substrate 111. The positive electrode conductive member 13 is not electrically connected to the first connecting sub-part 11221. The positive electrode conductive member 13 can be directly welded to the surface of the second connecting sub-part 11222 facing away from the supporting substrate 111, or it can be electrically connected by means of bonding, snap-fitting, etc. The positive electrode conductive member 13 electrically connects the second connecting sub-part 11222 of the positive electrode current collector 11 and the positive electrode lead-out portion 2011, thereby realizing the input and output of electrical energy.

[0203] The blocking member 51 can prevent lithium ions from contacting the first connector 11221. The blocking member 51 can cover a part of the surface of the first connector 11221 facing away from the support substrate 111, or it can cover the entire surface of the first connector 11221 facing away from the support substrate 111. The blocking member 51 can separate the lithium ions in the electrolyte from the first connector 11221, increasing the difficulty for lithium ions to contact the first connector 11221 and reducing the risk of the first connector 11221 forming a Li-Al alloy. The blocking member 51 can completely prevent lithium ions from passing through, or it can only allow a part of the lithium ions to pass through, thereby increasing the difficulty for lithium ions to contact the first connector 11221.

[0204] The blocking member 51 can directly cover the surface of the first connecting sub-part 11221 facing away from the support base 111. For example, the blocking member 51 and the surface of the first connecting sub-part 11221 facing away from the support base 111 can be covered by gravure printing, bonding or static adsorption. Other components (e.g., insulating member 52) can also be provided between the blocking member 51 and the surface of the first connecting sub-part 11221 facing away from the support base 111.

[0205] By adopting the technical solution of this embodiment, the positive electrode conductive member 13 is electrically connected to the second connecting part 11222 of the connecting part 1122 of the positive electrode lead-out portion and the positive electrode current collector 11, thereby realizing the transmission of electrical energy. The blocking member 51 covers at least a portion of the surface of the first connecting part 11221 of the connecting part 1122 that faces away from the supporting substrate 111. The blocking member 51 can separate the lithium ions in the electrolyte from at least a portion of the first connecting part 11221, preventing the lithium ions from contacting the first connecting part 11221. This increases the difficulty of lithium ions contacting the first connecting part 11221, reduces the risk of the first connecting part 11221 forming a Li-Al alloy, reduces the risk of the first connecting part 11221 undergoing powdering corrosion, reduces the risk of the connecting part 1122 being open-circuited, and reduces the risk of thermal runaway of the battery cell 100 under over-discharge conditions, thereby improving the reliability of the battery cell 100.

[0206] When the positive electrode potential is lower than the lithium intercalation potential, lithium ions easily form a Li-Al alloy upon contact with the first connector 11221, thereby corroding the first connector 11221, damaging the aluminum layer 112, and creating a local open circuit. This local open circuit is the root cause of over-discharge failure of the battery cell 100. However, in this embodiment, the battery cell 100, by using the blocking member 51 to cut off or block the pathway between the first connector 11221 and lithium ions, can effectively avoid or slow down the corrosion caused by the formation of Li-Al alloy in the first connector 11221, reducing the occurrence and probability of over-discharge failure in the battery cell 100. By using the blocking component 51 to cut off or block the pathway between the first connector 11221 and lithium ions, the corrosion degree of the first connector 11221 can be effectively alleviated, the original structure of the aluminum layer 112 can be maintained, the risk of reverse high voltage caused by the first connector 11221 being open-circuited can be reduced, thereby causing the battery cell 100 to fail, the corrosion resistance of the first connector 11221 to low voltage (positive electrode potential is less than lithium intercalation potential) can be improved, and the overall reliability of the battery cell 100 can be improved.

[0207] In some embodiments, the blocking member 51 is an insulating component.

[0208] The blocking component 51 is made of insulating material; for example, rubber, plastic, etc.

[0209] By adopting the technical solution of this embodiment, the blocking member 51 has insulation properties, which can isolate the first connecting part 11221 from other components (e.g., negative electrode 2, etc.), reduce the short circuit risk of the battery cell 100, and help improve the reliability of the battery cell 100.

[0210] In some embodiments, the insulating component is made of at least one of PP (Polypropylene), PET (Polyethylene terephthalate), or fiberglass.

[0211] PP parts are made of PP material. PET parts are made of PET material. Fiberglass parts are made of fiberglass material.

[0212] The materials used for insulating components include one or more of PP, PET, or glass fiber.

[0213] By adopting the technical solution of this embodiment, on the one hand, the PP part, PET part, and glass fiber part have good insulation properties, reducing the short-circuit risk of the battery cell 100, and can also prevent lithium ions from contacting the first connector 11221, reducing the risk of the first connector 11221 forming a Li-Al alloy; on the other hand, the PP part, PET part, and glass fiber part have good corrosion resistance properties, and can maintain a stable structural morphology in the electrolyte, thereby reliably preventing lithium ions from contacting the first connector 11221, reducing the risk of the first connector 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0214] In some embodiments, the electrode assembly 10 includes a negative electrode 2 and a separator 3, the separator 3 being used to separate the positive electrode 1 and the negative electrode 2, and the porosity of the blocking member 51 being less than the porosity of the separator 3.

[0215] Porosity is the ratio of the volume occupied by pores in a material to the total volume of the material, usually expressed as a percentage. Porosity is an important parameter for measuring the structural characteristics of porous materials, reflecting the degree of development and distribution of pores within the material. Porosity can be measured using the methods described in GB / T24586-2009.

[0216] By adopting the technical solution of this embodiment, lithium ions can pass through the pore channels in the blocking member 51 and come into contact with the first connecting part 11221. The porosity of the blocking member 51 is less than that of the separator 3, making it more difficult for lithium ions to pass through the blocking member 51 than for lithium ions to pass through the separator 3. This effectively increases the difficulty for lithium ions to pass through the blocking member 51 and come into contact with the first connecting part 11221, reduces the risk of the first connecting part 11221 forming a Li-Al alloy, reduces the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improves the reliability of the battery cell 100.

[0217] In some embodiments, the porosity of the blocking member 51 is less than or equal to 5%.

[0218] In some examples, the porosity of the barrier 51 can be 5% or any value between 0% and 5%. For example, the porosity of the barrier 51 is 0.1%, 1%, 2%, 3%, 4%, and 5%.

[0219] By adopting the technical solution of this embodiment, the porosity of the blocking member 51 is small, making it difficult for lithium ions to pass through the blocking member 51, reducing the risk of the first connecting part 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0220] In some embodiments, the porosity of the blocking member 51 is less than or equal to 2%, making it difficult for lithium ions to come into contact with the first connector 11221 through the blocking member 51. This effectively reduces the risk of the first connector 11221 forming a Li-Al alloy, lowers the risk of thermal runaway in the battery cell 100 under over-discharge conditions, and improves the reliability of the battery cell 100.

[0221] In some embodiments, the resistivity of the blocking element 51 is greater than or equal to 10. 12 Ω·cm.

[0222] Resistivity is a physical quantity that describes the degree to which a material impedes the flow of electric current. It is a scalar quantity used to measure the ability of a material to impede the flow of current per unit length and unit cross-sectional area. The higher the resistivity of the blocking element 51, the better its insulation performance.

[0223] Resistivity can be obtained using the four-probe method. During the test, the sample of the blocking component 51 is placed on the test platform, and the device is adjusted so that the four probes are gently pressed onto the sample, maintaining good contact and ensuring that the four probes are on the same straight line with uniform spacing. The test current is set to 10μA, and the value displayed on the instrument is recorded to obtain the conductivity of the blocking component 51.

[0224] The resistivity of the blocking element 51 can be 10. 12 Ω·cm and greater than 0 12 For any value of Ω·cm, for example, the resistivity of the blocking element 51 can be 10. 12 Ω·cm, 10 13 Ω·cm, 10 14 Ω·cm, 10 15 Ω·cm, 10 16 Ω·cm, 10 17 Ω·cm, 10 18 Ω·cm.

[0225] By adopting the technical solution of this embodiment, the resistivity of the blocking member 51 is greater than or equal to 10. 12 The Ω·cm value gives the blocking member 51 good insulation performance. The blocking member 51 can better insulate the first connecting part 11221 from other components, reduce the risk of short circuit in the battery cell 100, and improve the reliability of the battery cell 100.

[0226] In some embodiments, the resistivity of the blocking element 51 is greater than or equal to 10. 16 Ω·cm. This makes the blocking member 51 have better insulation performance. The blocking member 51 can better insulate the first connecting part 11221 and other components, reduce the risk of short circuit in the battery cell 100, and improve the reliability of the battery cell 100.

[0227] In some embodiments, the thickness of the blocking member 51 is T1, wherein T1 ≥ 5 μm.

[0228] The value of T1 can be 5 μm or any value greater than 5 μm. For example, the value of T1 can be 5 μm, 6 μm, 7 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, or 25 μm.

[0229] The design of T1≥5μm enables the blocking element 51 to effectively prevent lithium ions from passing through the blocking element 51, reducing the risk of lithium ions coming into contact with the first connector 11221, reducing the risk of the first connector 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0230] In some embodiments, 8μm≤T1≤18μm.

[0231] The design with T1 ≥ 8 μm allows the barrier 51 to better prevent lithium ions from passing through it, reducing the risk of lithium ions coming into contact with the first connector 11221, reducing the risk of Li-Al alloy formation in the first connector 11221, and lowering the risk of thermal runaway in the battery cell 100 under over-discharge conditions, thus improving the reliability of the battery cell 100. The design with T1 ≤ 18 μm reduces the space occupied by the barrier 51, which is beneficial to improving the volumetric energy density of the battery cell 100.

[0232] In some embodiments, the electrolyte is a liquid electrolyte, and the contact angle between the blocking member 51 and the liquid electrolyte is greater than or equal to 70°.

[0233] The contact angle between the barrier 51 and the liquid electrolyte refers to the angle formed between the surface of the barrier 51 and the liquid electrolyte droplet when a droplet of liquid electrolyte is placed on the surface of the barrier 51. This angle is an important parameter for measuring the wettability of the liquid electrolyte on the surface of the barrier 51, reflecting the hydrophilicity or hydrophobicity of the barrier 51 surface to the electrolyte. The larger the contact angle, the more difficult it is for the liquid electrolyte to wet the barrier 51.

[0234] Contact angle test: Take a sample from the blocking component 51 and use a microsyringe or pipette to drop an appropriate amount of liquid electrolyte onto the sample surface. Capture an image of the droplet on the surface using the camera of the contact angle measuring instrument. Analyze the acquired images using an algorithm to calculate the contact angle between the electrolyte and the sample surface.

[0235] The contact angle between the blocking member 51 and the liquid electrolyte can be 70° or any value greater than 70°. For example, the contact angle between the blocking member 51 and the liquid electrolyte can be 70°, 80°, 90°, 100°, 110°, 120°, 150°, or 170°.

[0236] By adopting the technical solution of this embodiment, the contact angle between the blocking member 51 and the liquid electrolyte is greater than or equal to 70°, which makes it difficult for the liquid electrolyte to wet the blocking member 51. Lithium ions in the electrolyte are not likely to come into contact with the first connector 11221 through the blocking member 51, thereby reducing the risk of the first connector 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0237] In some embodiments, the contact angle between the blocking member 51 and the liquid electrolyte is greater than or equal to 90°.

[0238] By adopting the technical solution of this embodiment, the liquid electrolyte is less likely to wet the blocking member 51, and the lithium ions in the electrolyte are less likely to come into contact with the first connector 11221 through the blocking member 51, thereby effectively reducing the risk of the first connector 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0239] In some embodiments, the positive electrode conductive member 13 and the positive electrode active material layer 12 are spaced apart, and the blocking member 51 covers at least a portion of the first connecting part 11221 located between the positive electrode conductive member 13 and the positive electrode active material layer 12.

[0240] The positive electrode conductive member 13 and the positive electrode active material layer 12 are spaced apart, and a gap is formed between the positive electrode conductive member 13 and the positive electrode active material layer 12, which separates the positive electrode conductive member 13 from the positive electrode active material layer 12, so that the positive electrode conductive member 13 does not come into contact with the positive electrode active material layer 12. The first connecting sub-part 11221 can be exposed through the gap, and the exposed part of the first connecting sub-part 11221 can be completely covered by the blocking member 51, or it can be partially covered by the blocking member 51.

[0241] In some examples, the positive conductive member 13 may cover the side of the first connector 11221 facing away from the positive active material layer 12, and other parts of the first connector 11221 may be exposed from the gap between the positive active material layer 12 and the positive conductive member 13.

[0242] In some examples, the positive electrode conductive member 13 may not cover the first connector portion 11221, and the entire first connector portion 11221 is exposed from the gap between the positive electrode active material layer 12 and the positive electrode conductive member 13.

[0243] By adopting the technical solution of this embodiment, the first connector 11221 can be exposed through the gap between the positive electrode conductive member 13 and the positive electrode active material layer 12, making it easier for lithium ions in the electrolyte to contact the first connector 11221. The blocking member 51 covers at least a portion of the exposed part of the first connector 11221, which can prevent lithium ions in the electrolyte from contacting the exposed part of the first connector 11221. This effectively reduces the risk of the first connector 11221 forming a Li-Al alloy, reduces the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improves the reliability of the battery cell 100.

[0244] In some embodiments, along a first direction, the side of the blocking member 51 facing away from the positive electrode conductive member 13 covers the end of the positive electrode active material layer 12 near the first connector portion 11221.

[0245] Based on the fact that the blocking member 51 covers the exposed portion of the first connecting part 11221, the blocking member 51 extends toward the positive electrode active material layer 12 and covers the surface of the positive electrode active material layer 12 facing away from the aluminum layer 112, such that the blocking member 51 covers the area of ​​the surface of the positive electrode active material layer 12 facing away from the aluminum layer 112 near the first connecting part 11221.

[0246] By adopting the technical solution of this embodiment, the blocking member 51 can cover the end of the positive electrode active material layer 12 near the first connector portion 11221. Due to the obstruction of the blocking member 51, lithium ions are less likely to pass through the positive electrode active layer near the end of the first connector portion 11221 and come into contact with the first connector portion 11221, thereby reducing the risk of the first connector portion 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0247] In some embodiments, the positive electrode active material layer 12 includes a first active material portion 121 and a second active material portion 122 arranged along a first direction. The end of the second active material portion 122 near the first connecting portion 11221 is connected to the first active material portion 121. The thickness of the first active material portion 121 is less than the thickness of the second active material layer. The blocking member 51 covers at least a portion of the surface of the first active material portion 121 facing away from the main body portion 1121, and the blocking member 51 does not cover the surface of the second active material portion 122 facing away from the main body portion 1121.

[0248] As an example, the positive electrode active material layer 12 is divided into two parts along the first direction, wherein the part closer to the first connector 11221 is the first active material part 121, and the part farther away from the first connector 11221 is the second active material part 122.

[0249] In some examples, the thickness of the first active material portion 121 is less than the thickness b of the second active material portion 122, such that the surface of the first active material portion 121 facing away from the main body portion 1121 is closer to the main body portion 1121 than the surface of the second active material portion 122 facing away from the main body portion 1121.

[0250] In some examples, the first active material portion 121 and the second active material portion 122 may have a generally equal thickness structure, with the thickness of the first active material portion 121 being less than the thickness b of the second active material portion 122, so that the first active material portion 121 and the second active material portion 122 form a stepped structure.

[0251] In some examples, the second active material portion 122 may have a generally uniform thickness structure. Along the direction from the main body portion 1121 to the connecting portion 1122, the thickness of the first active material portion 121 decreases starting from the second active material portion 122, such that the thickness of the first active material portion 121 is less than the thickness b of the second active material portion 122. The direction from the main body portion 1121 to the connecting portion 1122 can be found in [reference needed]. Figure 7 The positive direction of the Z-axis.

[0252] For example, along the direction from the main body 1121 to the connecting part 1122, the thickness of the first active material part 121 decreases in a stepped manner, making the first active material part 121 a stepped structure; or, along the direction from the main body 1121 to the connecting part 1122, the thickness of the first active material part 121 decreases slowly, and the shape of the first active material part 121 is more rounded or smooth, which helps to reduce stress concentration and improve the structural strength of the positive electrode 1.

[0253] The blocking member 51 covers a portion of the surface of the first active material portion 121 facing away from the main body portion 1121, or the blocking member 51 covers the entire surface of the first active material portion 121 facing away from the main body portion 1121, while the blocking member 51 does not cover the surface of the second active material portion 122 facing away from the main body portion 1121; along the thickness direction of the positive electrode current collector 11, the projection of the blocking member 51 coincides with the projection of the first active material portion 121, but does not coincide with the projection of the second active material portion 122.

[0254] By adopting the technical solution of this embodiment, during the forming process of the positive electrode sheet 1, the positive electrode active material layer 12 can be rolled to compress the positive electrode active material layer 12; and the provision of the first active material part 121 can reduce the rolling pressure on the edge of the positive electrode active material layer 12, reducing the risk of edge cracking of the positive electrode active material layer 12; in addition, the blocking member 51 can utilize the space on the side of the first active material part 121 facing away from the main body part 1121, reducing the risk of the blocking member 51 protruding from the surface of the second active material part 122 facing away from the main body part 1121, and reducing the problem of edge bulging after the positive electrode sheet 1 is wound.

[0255] In some embodiments, along the direction from the main body 1121 toward the positive electrode active material layer 12, the blocking member 51 does not protrude from the surface of the second active material portion 122 facing away from the main body 1121.

[0256] By adopting the technical solution of this embodiment, the blocking member 51 does not protrude from the surface of the second active material portion 122 facing away from the main body portion 1121, which can effectively reduce the problem of edge bulging after the positive electrode sheet 1 is wound.

[0257] Of course, in other examples, the blocking member 51 can also cover at least a portion of the surface of the second active material portion 122 facing away from the main body portion 1121.

[0258] In some embodiments, along the first direction, the size of the portion of the blocking member 51 covering the positive electrode active material layer 12 is W, wherein 0.1mm≤W≤1mm, and optionally, 0.2mm≤W≤0.5mm.

[0259] As an example, the value of W can be 0.1mm, 1mm, or any value between 0.1mm and 1mm. For example, the value of W can be, but is not limited to, 0.1mm, 0.2mm, 0.25mm, 0.3mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm.

[0260] With a W≥0.1mm design, the blocking element 51 can cover the end of the positive electrode active material layer 12 near the first connector 11221. Due to the obstruction of the blocking element 51, lithium ions are less likely to pass through the positive electrode active layer near the end of the first connector 11221 and come into contact with the first connector 11221, reducing the risk of Li-Al alloy formation in the first connector 11221 and reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, thus improving the reliability of the battery cell 100. With a W≤1mm design, the space occupied by the blocking element 51 is reduced, and the energy density of the battery cell 100 is increased. Therefore, the reliability and energy density of the battery cell 100 can be balanced.

[0261] In some embodiments, 0.2mm≤W4≤0.5mm can better balance the reliability and energy density of the battery cell 100.

[0262] In some embodiments, the blocking member 51 is bonded to the end of the positive electrode active material layer 12 near the first connector portion 11221.

[0263] The blocking member 51 is bonded to the surface of the positive electrode active material layer 12 facing away from the aluminum layer 112. An adhesive is provided between the blocking member 51 and the positive electrode active material layer 12, and the blocking member 51 and the positive electrode active material layer 12 are bonded together by the adhesive.

[0264] In some examples, the blocking member 51 is adhered to the surface of the first active material portion 121 facing away from the main body portion 1121.

[0265] By adopting the technical solution of this embodiment, the blocking member 51 is bonded to the positive electrode active material layer 12. On the one hand, the blocking member 51 can be fixed so that the blocking member 51 can stably prevent lithium ions from contacting the first connector 11221. On the other hand, the bonding between the blocking member 51 and the positive electrode active material layer 12 can also prevent lithium ions from passing between the blocking member 51 and the positive electrode active material layer 12, thereby preventing them from contacting the first connector 11221. This reduces the risk of the first connector 11221 forming a Li-Al alloy, lowers the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improves the reliability of the battery cell 100.

[0266] In some embodiments, the positive electrode sheet 1 further includes an insulating member 52, which covers at least a portion of the surface of the first connector 11221 facing away from the support substrate 111. At least a portion of the insulating member 52 is located between the positive electrode conductive member 13 and the positive electrode active material layer 12, and the portion of the insulating member 52 located between the positive electrode conductive member 13 and the positive electrode active material layer 12 is covered by a blocking member 51.

[0267] The insulating component 52 can refer to a component capable of insulation. The insulating component 52 covers a portion of the surface of the first connecting part 11221 facing away from the support substrate 111, or the insulating component 52 covers the entire surface of the first connecting part 11221 facing away from the support substrate 111. The insulating component 52 and the positive electrode active material layer 12 are distributed along a first direction. The insulating component 52 can be, but is not limited to, an insulating coating, an insulating adhesive (e.g., hot melt adhesive), or an insulating tape. The material of the insulating component 52 can be PP (Polypropylene), PET (Polyethylene Terephthalate), PI (Polyimide), etc.

[0268] For example, a portion of the insulating member 52 is located between the positive conductive member 13 and the positive active material layer 12, and another portion of the insulating member 52 may extend between the positive conductive member 13 and the first connecting sub-part 11221; or, the entire insulating member 52 is located between the positive conductive member 13 and the positive active material layer 12.

[0269] The insulating element 52 is located between the positive electrode conductive member 13 and the positive electrode active material layer 12. This portion is located between the first connecting sub-part 11221 and the blocking element 51. At least a portion of the surface of this portion facing away from the support substrate 111 is covered by the blocking element 51.

[0270] In some battery cells 100, the positive electrode conductive member 13 is bent before being connected to the positive electrode lead-out portion 2011. During the bending process of the positive electrode conductive member 13, the first connecting portion 11221 is also bent, which may cause cracks in the first connecting portion 11221. The insulating member 52 can cover the first connecting portion 11221 and support it, thereby reducing the risk of cracks in the first connecting portion 11221. In addition, the insulating member 52 covers the part of the first connecting portion 11221 located between the positive electrode conductive member 13 and the positive electrode active material layer 12, which can also achieve insulation of this part, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100. In the gap between the positive electrode conductive member 13 and the positive electrode active material layer 12, the blocking member 51 and the insulating member 52 can form a double-layer structure, which can effectively prevent lithium ions from contacting the first connector 11221, reduce the risk of the first connector 11221 forming a Li-Al alloy, reduce the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improve the reliability of the battery cell 100.

[0271] In some embodiments, the insulating member 52 covers the end of the positive electrode active material layer 12 near the connection portion 1122 and forms a covering area 60, and the blocking member 51 covers at least a portion of the surface of the covering area 60 facing away from the aluminum layer 112.

[0272] The end of the insulating member 52 near the positive electrode active material layer 12 covers the end of the positive electrode active material layer 12 near the connecting portion 1122, and the overlapping portion of the insulating member 52 and the positive electrode active material layer 12 forms a covering area 60.

[0273] In some examples, the insulating element 52 may also be attached to the end of the positive electrode active material layer 12 near the connection portion 1122 to form a covering area 60.

[0274] In some examples, a portion of the insulating element 52 can be embedded within the end of the positive electrode active material layer 12 near the connection portion 1122, thereby forming a covering area 60, which contains both positive electrode active material and insulating material. For example, the insulating element 52 may be made of hot melt adhesive material. When the hot melt adhesive is in contact with the positive electrode active material layer 12, it can be embedded within the gaps in the positive electrode active material layer 12, thereby forming the covering area 60. Of course, in other examples, the insulating element 52 may also be made of other materials.

[0275] A portion of the surface of the covered area 60 facing away from the aluminum layer 112 is covered with the blocking element 51, or the entire surface of the covered area 60 facing away from the aluminum layer 112 is covered with the blocking element 51.

[0276] By adopting the technical solution of this embodiment, the blocking member 51 can prevent lithium ions from contacting the first connecting part 11221 through the covered area 60, thereby reducing the risk of the first connecting part 11221 forming a Li-Al alloy, reducing the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improving the reliability of the battery cell 100.

[0277] In some embodiments, along the direction from the connecting portion 1122 to the main body portion 1121, the side of the blocking member 51 facing away from the positive electrode conductive member 13 protrudes from the edge of the covering area 60 facing away from the positive electrode conductive member 13.

[0278] Along the thickness direction of the positive current collector 11, the projection of the covering area 60 is located within the projection range of the blocking member 51. Along the direction from the connecting portion 1122 to the main body portion 1121, the blocking member 51 can extend from the positive conductive member 13 to the side of the covering area 60 opposite to the positive conductive member 13.

[0279] By adopting the technical solution of this embodiment, the blocking member 51 can completely cover the coverage area 60, which can effectively prevent lithium ions from contacting the first connecting part 11221 through the coverage area 60, reduce the risk of the first connecting part 11221 forming Li-Al alloy, reduce the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improve the reliability of the battery cell 100.

[0280] See Figure 8 As shown, the battery cell 100 may also exclude the insulating component 52, and the blocking component 51 extends directly from the first solder mark 41 to the positive electrode active material layer 12.

[0281] See Figures 9-12 As shown, in some embodiments, the positive electrode conductive member 13 includes a first conductive part 131 and a second conductive part 132. The first conductive part 131 is connected to the second conductive part 132. The first conductive part 131 is welded to the surface of the second connecting sub-part 11222 facing away from the support substrate 111 and forms a first solder mark 41.

[0282] The positive electrode conductive component 13 includes a first conductive portion 131 and a second conductive portion 132. The first conductive portion 131 refers to the part of the positive electrode conductive component 13 that is welded to the second connecting portion 11222. The trace left by the welding of the first conductive portion 131 and the second connecting portion 11222 is called the first weld mark 41. The second conductive portion 132 refers to the part that is electrically connected to the positive electrode conductive component 13. The number of second conductive portions 132 can be one or more. Multiple second conductive portions 132 are arranged at intervals along the length direction of the positive electrode sheet 1. The first conductive portion 131 and the second connecting portion 11222 can be welded by methods such as roll welding, laser welding, and ultrasonic welding.

[0283] By adopting the technical solution of this embodiment, the first conductive part 131 of the positive electrode conductive member 13 is welded to the second connecting part 11222, and the electrical connection between the positive electrode conductive member 13 and the second connecting part 11222 is simple and convenient to process and manufacture.

[0284] In some embodiments, along a first direction, the blocking member 51 covers at least a portion of the first solder mark 41 on the side opposite to the positive electrode active material layer 12.

[0285] The blocking member 51 covers the surface of the first conductive part 131 facing away from the second connecting part 11222. The blocking member 51 covers a portion of the first solder mark 41, or the blocking member 51 covers the entire first solder mark 41.

[0286] By adopting the technical solution of this embodiment, the blocking member 51 covers the first solder mark 41, which can block burrs, metal debris and other components on the first solder mark 41, reduce the short circuit risk of the battery cell 100 and improve the reliability of the battery cell 100. In addition, the blocking member 51 can also prevent lithium ions from moving to the first solder mark 41, reduce the risk of lithium ions moving to the first connector 11221 through the first solder mark 41, reduce the risk of the first connector 11221 forming a Li-Al alloy, reduce the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improve the reliability of the battery cell 100.

[0287] In some embodiments, along the direction from the main body 1121 to the connecting portion 1122, the side of the blocking member 51 facing away from the positive electrode active material layer 12 protrudes from the portion of the first solder mark 41 facing away from the positive electrode active material layer 12.

[0288] Along the thickness direction of the positive electrode current collector 11, the projection of the first solder mark 41 is located within the projection range of the blocking member 51. Along the direction from the main body 1121 to the connecting part 1122, the blocking member 51 can extend from the positive electrode active material layer 12 to the side of the first solder mark 41 opposite to the positive electrode active material layer 12.

[0289] By adopting the technical solution of this embodiment, the blocking member 51 can completely cover the first solder mark 41, which can effectively prevent lithium ions from contacting the first connector 11221 through the first solder mark 41, reduce the risk of the first connector 11221 forming a Li-Al alloy, reduce the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improve the reliability of the battery cell 100.

[0290] In some embodiments, the blocking member 51 is bonded to the first solder mark 41.

[0291] An adhesive is provided between the blocking member 51 and the first solder mark 41, and the blocking member 51 and the first solder mark 41 are bonded together by the adhesive.

[0292] By adopting the technical solution of this embodiment, the blocking member 51 is bonded to the first solder mark 41 layer. On the one hand, the blocking member 51 can be fixed, so that the blocking member 51 can better prevent lithium ions from contacting the first connector 11221. On the other hand, the blocking member 51 and the first solder mark 41 are bonded together, which can prevent lithium ions from passing through the gap between the blocking member 51 and the first solder mark 41, thereby preventing them from contacting the first connector 11221. This reduces the risk of the first connector 11221 forming a Li-Al alloy, reduces the risk of thermal runaway of the battery cell 100 under over-discharge conditions, and improves the reliability of the battery cell 100.

[0293] In some embodiments, the connecting portion 1122 includes a base portion 1131 and at least one protrusion 1132. The base portion 1131 is connected between the protrusion 1132 and the main body portion 1121. Along a second direction, the size l1 of the protrusion 1132 is smaller than the size L2 of the base portion 1131. The second direction is perpendicular to the first direction and the thickness direction of the positive electrode current collector 11. The first conductive portion 131 is welded to at least one of the base portion 1131 and the protrusion 1132 to form a first solder mark 41. The portion of the connecting portion 1122 located between the first solder mark 41 and the positive electrode active material layer 12 forms a first connecting sub-portion 11221, and the other portion of the connecting portion 1122 forms a second connecting sub-portion 11222.

[0294] The connecting portion 1122 includes a base portion 1131 and at least one protrusion 1132. The base portion 1131 connects the protrusion 1132 and the main body portion 1121. The protrusion 1132 is a protruding structure formed by extending outward from the edge of the base portion 1131 away from the main body portion 1121. Along the second direction, the dimension l1 of the protrusion 1132 is smaller than the dimension L2 of the base portion 1131. Along the second direction, the dimension L2 of the base portion 1131 is equal to or similar to the dimension L1 of the main body portion 1121.

[0295] In some examples, the protrusion 1132 is welded to the first conductive portion 131 to form a first solder mark 41.

[0296] In some examples, the base portion 1131 is welded to the first conductive portion 131 to form a first solder mark 41.

[0297] In some examples, both the base portion 1131 and the protrusion 1132 are welded to the first conductive portion 131 to form a first solder mark 41.

[0298] The connection portion 1122 is divided into two parts based on the edge of the first solder mark 41 near the positive electrode active material layer 12. The part located near the reference and close to the positive electrode active material layer 12 is the first connection sub-part 11221, and the part located far from the reference and away from the positive electrode active material layer 12 is the second connection sub-part 11222.

[0299] In the manufacturing process of some positive electrode sheets 1, positive electrode conductive components 13 of equal width are first welded to the edge of the connecting portion 1122 of equal width to form an equal width solder mark. Then, the edge of the positive electrode sheet 1 is die-cut to obtain the first conductive portion 131 and the second conductive portion 132 of the positive electrode conductive component 13, as well as the protrusion 1132 and the base portion 1131 of the positive electrode current collector 11.

[0300] By adopting the technical solution of this embodiment, the welding method between the first conductive part 131 and the connecting part 1122 is flexible and diverse, and can meet different usage requirements.

[0301] In some embodiments, the first solder mark 41 includes a first solder mark portion 411, and the protrusion 1132 is welded to the first conductive portion 131 to form the first solder mark portion 411.

[0302] The mark left by welding the protrusion 1132 to the first conductive part 131 is the first solder mark 411; if only the protrusion 1132 is welded to the first conductive part 131, the first solder mark 411 is the first solder mark 41. If both the protrusion 1132 and the base part 1131 are welded to the first conductive part 131, the first solder mark 411 is a part of the first solder mark 41.

[0303] By adopting the technical solution of this embodiment, the protrusion 1132 is welded to the first conductive part 131, which has a simple structure and is easy to process and manufacture.

[0304] In some embodiments, there are multiple protrusions 1132, which are arranged at intervals along a second direction. There are multiple first conductive parts 131, which are welded to the multiple protrusions 1132 in a one-to-one correspondence. There are multiple second conductive parts 132, which are connected to the multiple first conductive parts 131 in a one-to-one correspondence. The multiple second conductive parts 132 are electrically connected to the positive electrode lead-out portion 2011.

[0305] The positive electrode conductive component 13 is divided into multiple portions spaced apart along the second direction. Each portion includes a first conductive part 131 and a second conductive part 132. The multiple first conductive parts 131 are spaced apart along the second direction, and the multiple second conductive parts 132 are spaced apart along the second direction. The multiple first conductive parts 131 and the multiple second conductive parts 132 are connected one-to-one. The multiple first conductive parts 131 are welded one-to-one with the multiple protrusions 1132. The traces left by the welding of the multiple first conductive parts 131 and the multiple protrusions 1132 are the first solder marks 411.

[0306] By adopting the technical solution of this embodiment, the main body 1121 can be divided into multiple regions along the second direction according to multiple protrusions 1132, and each region can correspond to one protrusion 1132. Electrons in each region can be transferred to the electrode lead-out portion through the corresponding protrusion 1132, so that the electrons of the positive electrode current collector 11 are transferred in regions. The electron transmission path in each region to the corresponding protrusion 1132 is short, which helps to reduce the electron transmission distance, reduce the overall resistance of the positive electrode sheet 1, and improve the fast charging performance and reliability of the battery cell 100.

[0307] In some embodiments, the protrusion 1132 includes a first protrusion sub-part 11321 and a second protrusion sub-part 11322. The first protrusion sub-part 11321 is connected between the base portion 1131 and the second protrusion sub-part 11322. Along the second direction, the size l3 of the second protrusion sub-part 11322 is smaller than the size l2 of the first protrusion sub-part 11321. At least one of the first protrusion sub-part 11321 and the second protrusion sub-part 11322 is welded to the first conductive portion 131.

[0308] When the positive electrode 1 is in the unfolded state, the protrusion 1132 has a stepped structure. The protrusion 1132 is divided into two parts along the first direction. The larger part is the first protrusion sub-part 11321, and the smaller part is the second protrusion sub-part 11322. The first protrusion sub-part 11321 is closer to the base part 1131 than the second protrusion sub-part 11322.

[0309] In some examples, the first protruding sub-part 11321 is welded to the first conductive part 131 to form the first solder mark 411.

[0310] In some examples, the second protruding sub-part 11322 is welded to the first conductive part 131 to form the first solder mark 411.

[0311] In some examples, the first protruding sub-part 11321 and the second protruding sub-part 11322 are both welded to the first conductive part 131 to form the first solder mark part 411.

[0312] By adopting the technical solution of this embodiment, along the second direction, the size l3 of the second protruding sub-part 11322 is smaller than the size l2 of the first protruding sub-part 11321, and the size L2 of the protruding part 1132 near the base part 1131 is large, which is beneficial to improving the current carrying capacity of the part of the protruding part 1132 near the base part 1131, and is beneficial to improving the current carrying capacity of the positive electrode sheet 1; in addition, along the second direction, the size l3 of the second protruding sub-part 11322 is small, which is beneficial to reducing the space occupied by the protruding part 1132, and is beneficial to improving the energy density of the battery cell 100.

[0313] See Figures 13-16 As shown, in some embodiments, the first solder mark 41 includes a second solder mark portion 412, and the first conductive portion 131 is soldered to the surface of the base portion 1131 facing away from the supporting base 111 to form the second solder mark portion 412.

[0314] The trace left by welding the base portion 1131 to the first conductive portion 131 is the second solder mark 412. If only the base portion 1131 is welded to the first conductive portion 131, the second solder mark 412 is the first solder mark 41. If both the protrusion 1132 and the base portion 1131 are welded to the first conductive portion 131, the first solder mark 411 and the second solder mark 412 together form the first solder mark 41.

[0315] By adopting the technical solution of this embodiment, the first conductive part 131 is welded to the base part 1131. Along the second direction, the size L2 of the base part 1131 is large, which is beneficial to increase the welding area between the positive electrode conductive member 13 and the connecting part 1122, improve the current carrying capacity of the positive electrode sheet 1, and improve the reliability of the battery cell 100.

[0316] In some embodiments, along the second direction, the size of the main body portion 1121 is L1, and the size of the base portion 1131 is L2, wherein 0.8 ≤ L2 / L1 ≤ 1.

[0317] In some examples, along the second direction, the dimension L1 of the main body 1121 may refer to the length of the main body 1121.

[0318] In some examples, along the second direction, the dimension L2 of the base portion 1131 can refer to the length of the base portion 1131.

[0319] As an example, the value of L2 / L1 can be 0.8, 1, or any value between 0.8 and 1. For example, the value of L2 / L1 can be, but is not limited to, 0.8, 0.9, or 1.

[0320] In some examples, L2 / L1 = 1, and along the second direction, the size L1 of the main body 1121 is equal to the size L2 of the base 1131, so that the main body 1121 and the base 1131 form an equal length structure, which is more conducive to increasing the welding area of ​​the base 1131 and the first conductive part 131, thereby improving the current carrying capacity of the positive electrode 1 and improving the fast charging performance of the battery cell 100.

[0321] In some examples, 0.8 ≤ L2 / L1 < 1, along the second direction, the size L1 of the main body 1121 is larger than the size L2 of the base 1131, along the second direction, the base 1131 may be centrally located relative to the main body 1121, and the aluminum layer 112 forms a notch structure at the opposite ends of the base 1131. Alternatively, along the second direction, the base 1131 may be biased toward one end of the main body 1121. For example, one end of the base 1131 is flush with one end of the main body 1121, and the aluminum layer 112 forms a notch structure at the other end of the base 1131.

[0322] By adopting the technical solution of this embodiment, with the design of 0.8≤L2 / L1≤1, along the second direction, the size L1 of the main body 1121 is equal to or not much different from the size L2 of the base part 1131. The larger size L2 of the base part 1131 is beneficial to increase the size L2 of the base part 1131 and the welding area of ​​the first conductive part 131, thereby improving the current carrying capacity of the positive electrode 1 and improving the fast charging performance of the battery cell 100.

[0323] In some embodiments, along the second direction, the size of the second solder mark 412 is L3, and the size of the base portion 1131 is L2, wherein 0.8 ≤ L3 / L2 ≤ 1.

[0324] Along the second direction, the dimension L3 of the second solder mark 412 may refer to the length of the second solder mark 412.

[0325] As an example, the value of L3 / L2 can be 0.8, 1, or any value between 0.8 and 1. For example, the value of L3 / L2 can be, but is not limited to, 0.8, 0.9, or 1.

[0326] By adopting the technical solution of this embodiment, with the design of 0.8≤L3 / L2≤1, along the second direction, the size L3 of the second solder part 412 is equal to or not much different from the size L2 of the base part 1131, the welding area of ​​the base part 1131 and the first conductive part 131 is large, the overcurrent capacity of the positive electrode 1 is good, and the fast charging performance of the battery cell 100 is good.

[0327] In some embodiments, L3 / L2 = 1, and along the second direction, the size L3 of the second solder portion 412 is equal to the size L2 of the base portion 1131, which can effectively increase the welding area of ​​the base portion 1131 and the first conductive portion 131, resulting in good overcurrent capacity of the positive electrode 1 and good fast charging performance of the battery cell 100.

[0328] In some embodiments, the first solder mark 41 further includes a first solder mark portion 411, and the first conductive portion 131 includes a first conductive sub-portion 1311 and at least one second conductive sub-portion 1312. The first conductive sub-portion 1311 is connected between the second conductive sub-portion 1312 and the second conductive portion 132. The first conductive sub-portion 1311 is soldered to the surface of the base portion 1131 facing away from the supporting base 111 to form the second solder mark portion 412. The second conductive sub-portion 1312 is soldered to the surface of the protrusion 1132 facing away from the supporting base 111 to form the first solder mark portion 411.

[0329] Both the protrusion 1132 and the base portion 1131 are welded to the first conductive portion 131. The portion of the first conductive portion 131 welded to the base portion 1131 is the first conductive part 1311, and the portion of the first conductive portion 131 welded to the protrusion 1132 is the second conductive part 1312.

[0330] In some examples, when the positive electrode 1 is in the unfolded state, the first conductive portion 131 is divided into two parts along the first direction, wherein the part near the substrate portion 1131 is the first conductive part 1311, and the part covering the protrusion 1132 is the second conductive part 1312. The dividing line between the first conductive part 1311 and the second conductive part 1312 can be seen on the side of the substrate portion 1131 facing away from the positive electrode active material layer 12.

[0331] By adopting the technical solution of this embodiment, the protrusion 1132 and the base portion 1131 are simultaneously welded to the first conductive portion 131, which increases the welding area between the positive electrode conductive component 13 and the positive electrode current collector 11, which is beneficial to improve the current carrying capacity of the positive electrode sheet 1 and improve the fast charging capacity of the battery cell 100.

[0332] In some embodiments, the first solder mark 411 and the second solder mark 412 are directly connected.

[0333] The first solder mark 411 and the second solder mark 412 form a whole first solder mark 41, and there is no obvious dividing line between them; the whole first solder mark 41 can cover the dividing line between the protrusion 1132 and the base part 1131; in the actual manufacturing process, the first solder mark 411 and the second solder mark 412 are formed by die cutting the solder mark of equal width as described above.

[0334] In some examples, the first solder mark 411 and the second solder mark 412 adopt a solder joint structure, and the spacing between the solder joints in the first solder mark 411 is the same as the spacing between the solder joints in the second solder mark 412; for example, the solder joints in the first solder mark 411 and the second solder mark 412 are not welded to the boundary line between the protrusion 1132 and the base portion 1131, and the distance between two adjacent solder joints in the first solder mark 411 and the second solder mark 412 is equal to the spacing between the solder joints in the first solder mark 411; for example, the solder joints are welded to the boundary line between the protrusion 1132 and the base portion 1131, thereby connecting the first solder mark 411 and the second solder mark 412 into a single solder mark.

[0335] By adopting the technical solution of this embodiment, the first solder mark 411 and the second solder mark 412 form a whole first solder mark 41, which is convenient for processing and manufacturing and helps to reduce the manufacturing cost of the positive electrode sheet 1.

[0336] In some embodiments, there are multiple protrusions 1132, multiple second conductive portions 132, and multiple second conductive sub-portions 1312; along a second direction, multiple protrusions 1132 are spaced apart, multiple second conductive sub-portions 1312 are spaced apart, and multiple second conductive portions 132 are spaced apart; each second conductive sub-portion 1312 is connected to each other in a one-to-one correspondence with each other second conductive portion 132; a first conductive sub-portion 1311 is continuously arranged along the second direction, multiple second conductive sub-portions 1312 are connected to the first conductive sub-portion 1311, the first conductive sub-portion 1311 is welded to the base portion 1131, each second conductive sub-portion 1312 is welded to each protrusion 1132 in a one-to-one correspondence, and multiple second conductive portions 132 are electrically connected to the positive electrode lead-out portion 2011.

[0337] In some examples, when the positive electrode 1 is in the unfolded state, there are multiple second conductive parts 132 and multiple second conductive sub-parts 1312. Multiple second conductive sub-parts 1312 are spaced apart along the second direction and connected to the edge of the first conductive sub-part 1311 facing away from the positive electrode active material layer 12. The multiple second conductive parts 132 are respectively connected one-to-one to the edge of the multiple second conductive sub-parts 1312 facing away from the positive electrode active material layer 12.

[0338] For example, when the positive electrode 1 is in the unfolded state, the first conductive part 1311 extends outward from the edge opposite to the positive electrode active material layer 12 with multiple protrusions. Each protrusion is divided into two parts along a first direction: a part closer to the substrate 1131 is a second conductive part 1312, and a part farther from the substrate 1131 is a second conductive part 132. These multiple protrusions are spaced apart along a second direction, thereby forming multiple second conductive parts 132 and multiple second conductive parts 1312 arranged spaced apart along the second direction.

[0339] For example, when the positive electrode 1 is in the unfolded state, there are two second conductive parts 132 and two second conductive sub-parts 1312. The two second conductive sub-parts 1312 are spaced apart along the second direction and connected to the edge of the first conductive sub-part 1311 facing away from the positive electrode active material layer 12. The two second conductive parts 132 are respectively connected to the edge of the two second conductive sub-parts 1312 facing away from the positive electrode active material layer 12.

[0340] By adopting the technical solution of this embodiment, the first conductive part 1311 is continuously arranged along the second direction, and multiple second conductive parts 1312 can be connected into a whole. The first conductive part 1311 can provide good support for the second conductive parts 1312, which can reduce the risk between the second conductive parts 132 and the electrode plates of the inserted electrode assembly 10 when the second conductive parts 132 are bent, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100. In addition, the first conductive part 1311 is large in size along the second direction, which is conducive to increasing the welding area between the first conductive part 1311 and the base part 1131, which is conducive to improving the current carrying capacity of the positive electrode plate 1, and improving the fast charging performance and reliability of the battery cell 100.

[0341] See Figure 17 As shown, in some embodiments, there are two aluminum layers 112, which are respectively connected to opposite sides of the support substrate 111 along the thickness direction of the positive current collector 11; there are two positive conductive members 13, whose first conductive portions 131 are respectively welded to the second connecting portions 11222 of the two aluminum layers 112 to form two first solder marks 41; there are two positive active material layers 12, which respectively cover the surfaces of the main body portions 1121 of the two aluminum layers 112 facing away from the support substrate 111; there are two blocking members 51, which respectively cover at least a portion of the surfaces of the first connecting portions 11221 of the two aluminum layers 112 facing away from the support substrate 111.

[0342] By adopting the technical solution of this embodiment, both opposite sides of the positive current collector 11 are covered with a positive active material layer 12, which can increase the capacity of the active material on the positive electrode sheet 1, and is beneficial to improving the capacity and energy density of the battery cell 100. The two blocking members 51 can respectively protect the first connecting parts 11221 of the two aluminum layers 112, reduce the risk of Li-Al alloy formation in the first connecting parts 11221, reduce the risk of powdering corrosion in the first connecting parts 11221, reduce the risk of open circuit in the connecting parts 1122, and reduce the risk of thermal runaway of the battery cell 100 under over-discharge conditions, thereby improving the reliability of the battery cell 100. In addition, the two positive conductive members 13 can electrically connect the aluminum layers 112 on both sides, thereby breaking the insulation limitation of the supporting substrate 111 on the two aluminum layers 112, which can effectively improve the conductivity of the positive electrode sheet 1, improve the fast charging performance of the battery cell 100, reduce the heat generation of the battery cell 100, and improve the reliability of the battery cell 100.

[0343] In some embodiments, along the direction from the main body portion 1121 to the connecting portion 1122, the portion of the blocking member 51 protruding from the base portion 1131 forms a blocking portion 511. Along the second direction, the blocking portion 511 is located on one side of the second conductive portion 132, wherein the second direction is perpendicular to the first direction and the thickness direction of the positive current collector 11.

[0344] The blocking portion 511 can refer to the portion of the blocking member 51 that protrudes from the side of the substrate portion 1131 away from the positive electrode active material layer 12. The blocking portion 511 is located on the side of the second conductive portion 132 along the second direction.

[0345] In some examples, the blocking member 51 has a uniform width structure. The blocking member 51 can cover the first conductive part 131 and the second conductive part 132. The portion of the blocking member 51 that protrudes from the edge of the first conductive part 1311 away from the positive electrode active material layer 12 and is located on one side of the second conductive part 132 forms the blocking part 511.

[0346] In some examples, the projection of the blocking portion 511 does not coincide with the projection of the positive electrode conductive member 13 along the thickness direction of the positive electrode current collector 11.

[0347] During the manufacturing process of the positive electrode sheet 1, the edges of the substrate portion 1131 and the first conductive electronic portion 1311 away from the positive electrode active material layer 12 are die-cut. Burrs, metal debris, and other components may be generated at the edges of the substrate portion 1131 and the first conductive electronic portion 1311 away from the positive electrode active material layer 12. Alternatively, during the use of the positive electrode sheet 1, metal debris and other components may be easily generated at the edges of the substrate portion 1131 and the first conductive electronic portion 1311 away from the positive electrode active material layer 12 under external force, which increases the short circuit risk of the battery cell 100. The blocking portion 511 can block burrs, metal debris, and other components at the edges of the substrate portion 1131 away from the positive electrode active material layer 12, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0348] In some embodiments, the blocking portions 511 of the two blocking members 51 are in contact with each other.

[0349] Along the thickness direction of the positive current collector 11, two blocking members 51 are located on opposite sides of the positive electrode sheet 1. Along the first direction, the blocking portions 511 of the two blocking members 51 are offset from the second conductive portion 132, so that the blocking portions 511 of the two blocking members 51 can be directly attached. The blocking portions 511 of the two blocking members 51 can be attached by means of, but not limited to, bonding or static adsorption.

[0350] By adopting the technical solution of this embodiment, after the blocking portions 511 of the two blocking members 51 are attached, the burrs, metal debris and other components on the edge of the base portion 1131 can be wrapped, reducing the risk of metal debris falling off, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0351] See Figure 7 As shown, in some embodiments, along the first direction, the second conductive portion 132 is located on the side of the protrusion 1132 facing away from the base portion 1131, and the second conductive portions 132 of the two positive electrode conductive members 13 are welded together to form a second solder mark 42.

[0352] When the positive electrode 1 is in the unfolded state, the second conductive part 132 is located on the side of the protrusion 1132 facing away from the base part 1131, so that the two positive electrode conductive members 13 can be directly attached and welded together. The second conductive parts 132 of the two positive electrode conductive members 13 are welded together to form a whole, thereby breaking the insulation limitation of the supporting base 111 and facilitating connection with the positive electrode lead-out part.

[0353] In some embodiments, the blocking element 51 covers at least a portion of the second solder mark 42.

[0354] The blocking element 51 may cover a portion of the second solder mark 42, or the blocking element 51 may cover the entire second solder mark 42.

[0355] By adopting the technical solution of this embodiment, the blocking member 51 can cover the second solder mark 42, and can block the sharp protrusions, metal debris and other components on the second solder mark 42, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0356] In some embodiments, the thickness of the connecting portion 1122 is T2, wherein 0.1μm≤T2≤5μm.

[0357] The value of T2 can be 0.1μm, 5μm, or any value between 0.1μm and 5μm. For example, the value of T2 can be, but is not limited to, 0.1μm, 0.5μm, 1μm, 1.5μm, 2μm, 3μm, 4μm, or 5μm.

[0358] The design with a thickness of 0.1μm ≤ T2 ≤ 5μm results in a smaller thickness T2 for the connection portion 1122. A thinner connection portion 1122 helps reduce the weight and cost of the positive electrode current collector 11, while also increasing the energy density of the battery cell 100. However, a smaller thickness T2 also means poorer current carrying capacity and more severe heat generation in the connection portion 1122. Consequently, in the event of over-discharge of the battery cell 100, the lithium intercalation potential is higher, increasing the risk of thermal runaway. The blocking member 51 in this embodiment can prevent lithium ions from intercalating into the first connecting portion 11221, reducing the risk of Li-Al alloy formation, pulverization corrosion of the first connecting portion 11221, and open circuit formation in the connection portion 1122. This reduces the risk of thermal runaway in the battery cell 100 under over-discharge conditions, improving the reliability of the battery cell 100. Therefore, both the reliability and energy density of the battery cell 100 can be simultaneously considered.

[0359] In some embodiments, 1μm≤T2≤4μm can better balance the reliability and energy density of the battery cell 100.

[0360] In some embodiments, 1.5μm≤T2≤2μm. This allows for a better balance between the reliability and energy density of the battery cell 100.

[0361] In some embodiments, the thickness T2 of the connecting portion 1122 is greater than at least a portion of the thickness of the main body portion 1121.

[0362] For example, the main body 1121 and the connecting part 1122 are of equal thickness, the thickness of the main body 1121 is less than the thickness T2 of the connecting part 1122, and the main body 1121 and the connecting part 1122 form a stepped structure.

[0363] For example, the main body 1121 has an uneven thickness structure, and the connecting part 1122 has an equal thickness structure. The main body 1121 is divided into a first part 11211 and a second part 11212. The first part 11211 is connected between the second part 11212 and the connecting part 1122. The thickness of the first part 11211 is greater than the thickness of the second part 11212. The thickness T2 of the connecting part 1122 is greater than the thickness of the second part 11212. The thickness T2 of the connecting part 1122 is greater than or equal to the thickness of the first part 11211. The first part... The first part 11211 and the second part 11212 can be directly connected. The first part 11211 and the second part 11212 can also be connected through the third part 11213. Along the direction from the main body 1121 to the connecting part 1122, the thickness of the third part 11213 increases from the thickness of the second part 11212 to the thickness of the first part 11211. The third part 11213 can smoothly transition between the second part 11212 and the third part 11213, reducing stress concentration in the positive electrode current collector 11 and improving the structural strength of the positive electrode current collector 11.

[0364] By adopting the technical solution of this embodiment, the thickness T2 of the connecting portion 1122 is relatively large, and the current carrying capacity of the connecting portion 1122 is good, which is beneficial to improving the current carrying capacity of the positive electrode sheet 1. In addition, the large thickness T2 of the connecting portion 1122 results in a low lithium intercalation potential when the battery cell 100 is over-discharged, which helps to reduce the risk of the first connecting sub-portion 11221 forming Li-Al alloy, reduces the risk of powdering corrosion of the first connecting sub-portion 11221, reduces the risk of open circuit of the connecting portion 1122, and reduces the risk of thermal runaway of the battery cell 100 under over-discharge conditions, thereby improving the reliability of the battery cell 100.

[0365] In some embodiments, the positive electrode 1 includes a conductive protective layer 14, at least a portion of which is located between the positive electrode active material layer 12 and the main body portion 1121.

[0366] The conductive protective layer 14 is conductive and can protect the main body 1121. The conductive protective layer 14 can electrically connect the positive electrode active material layer 12 and the main body 1121 to realize the charging and discharging of the battery cell 100.

[0367] In some examples, the conductive protective layer 14 can be made of a mixture of a conductive agent and a binder. The binder bonds the positive electrode active material layer 12 to the main body 1121, while the conductive agent is responsible for conducting electrons. The conductive agent can be carbon black, graphite, etc., and the binder can be polyvinylidene fluoride, etc. Among them, carbon black can reduce the contact resistance between the particles in the positive electrode active material layer 12 and the aluminum layer 112, which is beneficial to improving the performance of the battery cell 100.

[0368] The conductive protective layer 14 may be located partly between the positive electrode active material layer 12 and the main body portion 1121, and partly outside the positive electrode active material layer 12. For example, the end of the conductive protective layer 14 near the positive electrode conductive member 13 covers the first connecting sub-portion 11221; or, the entire conductive protective layer 14 may be located between the positive electrode active material layer 12 and the main body portion 1121.

[0369] The aluminum layer 112 is relatively thin. During the rolling process of the positive electrode sheet 1, the particles in the positive electrode active material layer 12 are prone to squeezing the main body 1121, which can easily cause cracks in the main body 1121 and affect the conductivity of the main body 1121. The conductive protective layer 14 can play a buffering and lubricating role between the positive electrode active material layer 12 and the main body 1121, which can alleviate the damage to the main body 1121 caused by the particles in the positive electrode active material layer 12 during the rolling process of the positive electrode sheet 1. This is beneficial to improving the conductivity of the main body 1121 and improving the current carrying capacity of the positive electrode sheet 1.

[0370] In some embodiments, the support substrate 111 is an insulating substrate.

[0371] By adopting the technical solution of this embodiment, the support substrate 111 is made of insulating material, which can reduce internal short circuits caused by puncture, reduce the probability of internal short circuits in the battery cell 100, and improve the reliability of the battery cell 100.

[0372] In some embodiments, see Figure 2 As shown, a battery device 1100 is provided, which includes a plurality of the aforementioned battery cells 100.

[0373] The battery device 1100 of this application embodiment adopts the above-described battery cell 100, and the reliability of the battery cell 100 is conducive to improving the reliability of the battery device 1100.

[0374] In some embodiments, an electrical device is provided, including the battery cell 100 or the battery device 1100 described above, wherein the battery cell 100 or the battery device 1100 is used to store or provide electrical energy.

[0375] The electrical device of this application embodiment uses the above-mentioned battery cell 100 and battery device 1100, which improves the reliability of the electrical device.

[0376] The following description is based on some specific embodiments.

[0377] Example 1

[0378] See Figures 3-7 ,as well as Figures 9-12As shown, in this embodiment, the battery cell 100 includes a housing 20 and an electrode assembly 10. The housing 20 includes an end cap 201 and a shell 202. The electrode assembly 10 is located inside the shell 202. The end cap 201 covers the opening of the shell 202 and has a positive electrode terminal and a negative electrode terminal. The electrode assembly 10 has a wound structure and includes a positive electrode plate 1, a negative electrode plate 2 and a separator 3. The separator 3 is disposed between the positive electrode plate 1 and the negative electrode plate 2.

[0379] In this embodiment, the positive electrode sheet 1 includes a positive current collector 11, a positive conductive member 13, and a positive active material layer 12. The positive current collector 11 includes a supporting substrate 111 and aluminum layers 112 disposed on both sides of the supporting substrate 111. The aluminum layer 112 includes a main body portion 1121 and a connecting portion 1122 arranged and connected along a first direction. The main body portion 1121 is covered by the positive active material layer 12, and the connecting portion 1122 is not covered by the positive active material layer 12. The first direction is perpendicular to the thickness direction of the positive current collector 11. A conductive protective layer 14 is provided between the main body portion 1121 and the positive active material layer 12.

[0380] In this embodiment, the connecting portion 1122 includes a first connecting sub-portion 11221 and a second connecting sub-portion 11222, with the first connecting sub-portion 11221 connected between the main body portion 1121 and the second connecting sub-portion 11222.

[0381] In this embodiment, the positive electrode conductive component 13 includes a first conductive portion 131 and a second conductive portion 132 connected to each other. The second conductive portion 132 is electrically connected to the positive electrode terminal. The first conductive portion 131 and the second connecting portion 11222 are welded to form a first solder mark 41. The portion of the connecting portion 1122 located between the first solder mark 41 and the positive electrode active material layer 12 forms the first connecting portion 11221, and the remaining portion of the connecting portion 1122 forms the second connecting portion 11222.

[0382] In this embodiment, the connecting portion 1122 includes a base portion 1131 and a protrusion 1132. The base portion 1131 is connected between the protrusion 1132 and the main body portion 1121. The protrusion 1132 includes a first protrusion sub-portion 11321 and a second protrusion sub-portion 11322. The first protrusion sub-portion 11321 is connected between the base portion 1131 and the second protrusion sub-portion 11322. Along the second direction, the size l3 of the second protrusion sub-portion 11322 is smaller than the size l2 of the first protrusion sub-portion 11321. Both the first protrusion sub-portion 11321 and the second protrusion sub-portion 11322 are welded to the first conductive portion 131 to form a first solder mark 411. The second direction is perpendicular to the first direction and the thickness direction of the positive electrode current collector 11. The first solder mark 411 forms the first solder mark 41.

[0383] In this embodiment, there are two positive conductive components 13, and the second conductive portions 132 of the two positive conductive components 13 are welded together to form a second solder mark 42.

[0384] In this embodiment, the battery cell 100 further includes an insulating member 52, and the second connecting part 11222 is covered by the insulating member 52. The insulating member 52 is located between the first conductive part 131 and the positive electrode active material layer 12.

[0385] In this embodiment, the battery cell 100 further includes a blocking member 51, which covers the second solder mark 42, the first solder mark 41, the insulating member 52 and the end of the positive electrode active material layer 12 near the first connector 11221. The positive electrode conductive member 13, the insulating member 52 and the positive electrode active material layer 12 are all bonded to the blocking member 51.

[0386] Example 2

[0387] See Figures 13-16 As shown, the difference between this embodiment and Embodiment 1 is that: the first solder mark 41 further includes a second solder mark portion 412, the substrate portion 1131 includes a main body portion 1121 and a substrate portion 1131 arranged and connected along a first direction, the substrate portion 1131 is connected between the main body portion 1121 and the protrusion 1132; at least a portion of the main body portion 1121 is covered with a positive electrode active material layer 12, and the main body portion 1121 forms the main body portion 1121; the substrate portion 1131 is not covered with a positive electrode active material layer 12.

[0388] The first conductive portion 131 includes a first conductive sub-portion 1311 and a second conductive sub-portion 1312. The second conductive sub-portion 1312 is connected between the first conductive sub-portion 1311 and the second conductive portion 1312. The first conductive sub-portion 1311 is welded to the surface of the base portion 1131 facing away from the supporting base 111 to form a second solder mark 412. The second conductive sub-portion 1312 is welded to the surface of the protrusion 1132 facing away from the supporting base 111 to form a first solder mark 411. The first solder mark 411 and the second solder mark 412 together form the first solder mark 41. The protrusion 1132 is not a stepped structure.

[0389] Example 3

[0390] See Figure 8 As shown, the difference between this embodiment and embodiment 2 is that the battery cell 100 does not include the insulating component 52.

[0391] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0392] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The outer casing contains an electrolyte having lithium ions; the outer casing is provided with a positive electrode lead-out portion; An electrode assembly includes a positive electrode sheet, the positive electrode sheet including a positive current collector, a positive conductive component and a positive active material layer, the positive conductive component being electrically connected to the positive electrode lead-out portion; The positive electrode current collector includes a connected support substrate and an aluminum layer. The support substrate, the aluminum layer, and the positive electrode active material layer are stacked along the thickness direction of the positive electrode current collector, and the aluminum layer is located between the positive electrode active material layer and the support substrate. The aluminum layer includes a main body portion and a connecting portion arranged and connected along a first direction. At least a portion of the main body portion is covered by the positive electrode active material layer, and the connecting portion is not covered by the positive electrode active material layer. The first direction is perpendicular to the thickness direction of the positive electrode current collector. The connecting portion includes a first connecting sub-port and a second connecting sub-port. The first connecting sub-port is connected between the main body portion and the second connecting sub-port. The positive electrode conductive member is electrically connected to the surface of the second connecting sub-port facing away from the supporting substrate. The positive electrode also includes a blocking member that covers at least a portion of the surface of the first connector facing away from the support substrate.

2. The battery cell according to claim 1, characterized in that: The blocking component is an insulating part.

3. The battery cell according to claim 2, characterized in that: The insulating component includes at least one of PP, PET, or fiberglass.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The electrode assembly includes a negative electrode and an isolator, the isolator being used to separate the positive electrode and the negative electrode, and the porosity of the isolator being less than that of the isolator.

5. The battery cell according to any one of claims 1 to 3, characterized in that: The porosity of the blocking element is less than or equal to 5%, and optionally, the porosity of the blocking element is less than or equal to 2%.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The resistivity of the blocking element is greater than or equal to 10. 12 Ω·cm, optionally, the resistivity of the blocking element is greater than or equal to 10 Ω·cm. 16 Ω·cm.

7. The battery cell according to any one of claims 1 to 3, characterized in that: The thickness of the blocking element is T1, wherein T1 ≥ 5 μm, and optionally, 8 μm ≤ T1 ≤ 18 μm.

8. The battery cell according to any one of claims 1 to 3, characterized in that: The electrolyte is a liquid electrolyte, and the contact angle between the blocking member and the liquid electrolyte is greater than or equal to 70°; optionally, the contact angle between the blocking member and the liquid electrolyte is greater than or equal to 90°.

9. The battery cell according to any one of claims 1 to 3, characterized in that: The positive electrode conductive member is spaced apart from the positive electrode active material layer, and the blocking member covers at least a portion of the first connecting sub-part located between the positive electrode conductive member and the positive electrode active material layer.

10. The battery cell according to claim 9, characterized in that: Along the first direction, the side of the blocking member facing away from the positive electrode conductive member covers the end of the positive electrode active material layer near the first connector.

11. The battery cell according to claim 10, characterized in that: The positive electrode active material layer includes a first active material portion and a second active material portion arranged along the first direction. The end of the second active material portion near the first connector portion is connected to the first active material portion. The surface of the first active material portion facing away from the main body portion is closer to the main body portion than the surface of the second active material portion facing away from the main body portion. The blocking member covers at least a portion of the surface of the first active material portion facing away from the main body portion, while the blocking member does not cover the surface of the second active material portion facing away from the main body portion.

12. The battery cell according to claim 11, characterized in that: Along the direction from the main body to the positive electrode active material layer, the blocking member does not protrude from the surface of the second active material portion facing away from the main body.

13. The battery cell according to claim 10, characterized in that: Along the first direction, the size of the portion of the barrier covering the positive electrode active material layer is W, wherein 0.1mm≤W≤1mm, and optionally, 0.2mm≤W≤0.5mm.

14. The battery cell according to claim 10, characterized in that: The blocking element is bonded to the end of the positive electrode active material layer near the first connector.

15. The battery cell according to claim 9, characterized in that: The positive electrode sheet further includes an insulating member that covers at least a portion of the surface of the first connector facing away from the support substrate. At least a portion of the insulating member is located between the positive electrode conductive member and the positive electrode active material layer. The portion of the insulating member located between the positive electrode conductive member and the positive electrode active material layer is covered by the blocking member.

16. The battery cell according to claim 15, characterized in that: The insulating element covers the end of the positive electrode active material layer near the connection portion and forms a covering area, and the blocking element covers at least a portion of the surface of the covering area facing away from the aluminum layer.

17. The battery cell according to claim 16, characterized in that: Along the direction from the connecting portion to the main body portion, the side of the blocking member facing away from the positive conductive member protrudes from the edge of the covered area facing away from the positive conductive member.

18. The battery cell according to any one of claims 1 to 3, characterized in that: The positive conductive component includes a first conductive part and at least one second conductive part. The first conductive part is connected to the second conductive part. The first conductive part is welded to the surface of the second connecting part facing away from the support substrate and forms a first solder mark.

19. The battery cell according to claim 18, characterized in that: Along the first direction, the side of the barrier opposite to the positive electrode active material layer covers at least a portion of the first solder mark.

20. The battery cell according to claim 19, characterized in that: Along the direction from the main body to the connecting portion, the side of the blocking member facing away from the positive electrode active material layer protrudes beyond the portion of the first solder mark facing away from the positive electrode active material layer.

21. The battery cell according to claim 19, characterized in that: The blocking element is bonded to the first solder mark.

22. The battery cell according to claim 18, characterized in that: The connecting portion includes a base portion and at least one protrusion. The base portion is connected between the protrusion and the main body portion. Along a second direction, the size of the protrusion is smaller than the size of the base portion. The second direction is perpendicular to the first direction and the thickness direction of the positive current collector. The first conductive portion is welded to at least one of the base portion and the protrusion to form the first solder mark. The portion of the connection located between the first solder mark and the positive electrode active material layer forms the first connection sub-part, and the other portion of the connection forms the second connection sub-part.

23. The battery cell according to claim 22, characterized in that: The first solder mark includes a first solder mark portion, wherein the protrusion is welded to the first conductive portion to form the first solder mark portion.

24. The battery cell according to claim 23, characterized in that: The protrusion includes a first protruding sub-part and a second protruding sub-part. The first protruding sub-part is connected between the base part and the second protruding sub-part. Along the second direction, the size of the second protruding sub-part is smaller than the size of the first protruding sub-part. At least one of the first protruding sub-part and the second protruding sub-part is welded to the first conductive part.

25. The battery cell according to claim 22, characterized in that: The first solder mark includes a second solder mark portion, wherein the first conductive portion is soldered to the surface of the base portion facing away from the supporting base to form the second solder mark portion.

26. The battery cell according to claim 25, characterized in that: Along the second direction, the size of the main body is L1, and the size of the base is L2, wherein 0.8 ≤ L2 / L1 ≤ 1.

27. The battery cell according to claim 25, characterized in that: Along the second direction, the size of the second solder mark is L3, and the size of the base portion is L2, wherein 0.8 ≤ L3 / L2 ≤ 1.

28. The battery cell according to claim 26, characterized in that: The first solder mark further includes a first solder mark portion, the first conductive portion includes a first conductive sub-part and at least one second conductive sub-part, the second conductive sub-part is connected between the first conductive sub-part and the second conductive portion, the first conductive sub-part is soldered to the surface of the base portion facing away from the supporting base to form the second solder mark portion, and the second conductive sub-part is soldered to the surface of the protrusion facing away from the supporting base to form the first solder mark portion.

29. The battery cell according to claim 28, characterized in that: The first solder mark and the second solder mark are directly connected.

30. The battery cell according to claim 28, characterized in that: The number of protrusions is multiple, the number of second conductive parts is multiple, and the number of second conductive subparts is multiple; Along the second direction, a plurality of protrusions are spaced apart, a plurality of second conductive parts are spaced apart, and a plurality of second conductive parts are spaced apart; each second conductive part is connected to each second conductive part in a one-to-one correspondence. The first conductive part is continuously arranged along the second direction, and a plurality of second conductive parts are connected to the side of the first conductive part facing away from the base part. Each second conductive part is welded to each of the protrusions in a one-to-one correspondence, and the plurality of second conductive parts are electrically connected to the positive electrode lead-out part.

31. The battery cell according to claim 22, characterized in that: The number of aluminum layers is two, and the two aluminum layers are respectively connected to the two opposite sides of the support substrate along the thickness direction of the positive electrode current collector; The number of positive electrode conductive components is two, and the first conductive parts of the two positive electrode conductive components are respectively welded to the second connecting parts of the two aluminum layers to form two first solder marks; The number of positive electrode active material layers is two, and the two positive electrode active material layers respectively cover the surface of the main body of the two aluminum layers facing away from the supporting substrate; The number of the blocking elements is two, and the two blocking elements respectively cover at least a portion of the surface of the first connecting part of the two aluminum layers facing away from the supporting substrate.

32. The battery cell according to claim 31, characterized in that: Along the direction from the main body to the connecting portion, the portion of the blocking member protruding from the base portion forms a blocking portion. Along the second direction, the blocking portion is located on one side of the second conductive portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the positive current collector.

33. The battery cell according to claim 32, characterized in that: The blocking portions of the two blocking members are in contact with each other.

34. The battery cell according to claim 31, characterized in that: Along the first direction, the second conductive portion is located on the side of the protrusion facing away from the base portion, and the second conductive portions of the two positive electrode conductive components are welded together to form a second solder mark.

35. The battery cell according to claim 34, characterized in that: The blocking element covers at least a portion of the second solder mark.

36. The battery cell according to any one of claims 1 to 3, characterized in that: The thickness of the connecting part is T2, wherein 0.1μm≤T2≤2μm, and optionally, 0.5μm≤T2≤1.5μm.

37. The battery cell according to any one of claims 1 to 3, characterized in that: The thickness of the connecting portion is greater than at least a portion of the thickness of the main body portion.

38. The battery cell according to any one of claims 1 to 3, characterized in that: The positive electrode includes a conductive protective layer, at least a portion of which is located between the positive electrode active material layer and the main body.

39. The battery cell according to any one of claims 1 to 3, characterized in that: The supporting substrate is an insulating substrate.

40. A battery device, characterized in that: It includes multiple battery cells according to any one of claims 1 to 39.

41. An electrical device, characterized in that: Includes a battery cell according to any one of claims 1 to 39 or a battery device according to claim 40, wherein the battery cell or the battery device is used to store or provide electrical energy.

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