Cylindrical battery and electric device

Abstract

The application relates to the technical field of batteries, in particular to a cylindrical battery and an electric device. The cylindrical battery comprises a shell, a winding core, electrolyte and a current collecting disc. The winding core comprises a positive electrode sheet, a negative electrode sheet and a separator, is arranged in the shell, has a tab, and the electrolyte is arranged in the shell. The current collecting disc is arranged in the shell, is provided with a contact protrusion on one side facing the winding core, and the tab is in abutment with the contact protrusion. The contact protrusion is arranged on the current collecting disc, the tab and the contact protrusion form stable and reliable point contact or line contact, the local contact pressure is increased and the electronic transmission path is optimized, the contact resistance and ohmic resistance between the current collecting disc and the tab are effectively reduced, the battery can support a higher charging and discharging current, the rate performance and power output capacity are improved. Meanwhile, due to the existence of the contact protrusion, a gap exists between the current collecting disc and the winding core, a small movement space is provided for the tab, and the tab is prevented from being torn due to stress concentration.

Description

Technical Field

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

[0002] With the increasing demands for range in new energy vehicles and energy storage systems, improving battery energy density and pursuing high-rate discharge have become core directions for industry development. Currently, cylindrical batteries mostly use high-nickel ternary cathode materials. However, while these materials offer high specific capacity, they are also prone to gas generation during high-temperature cycling, causing battery swelling. If a current collector with non-fully covered tabs is used to alleviate gas generation, it reduces the stable and effective contact between the current collector and the tabs, leading to increased battery impedance. Furthermore, insufficient wettability of the electrode sheets during high-rate charge and discharge can also affect the battery's rate performance. Summary of the Invention

[0003] This application provides a cylindrical battery and an electrical device for reducing the internal resistance of the battery.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] On one hand, this application provides a cylindrical battery, comprising:

[0006] case;

[0007] A core is disposed in a housing. The core includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a positive current collector and a positive active material disposed on the positive current collector. The negative electrode sheet includes a negative current collector and a negative active material disposed on the negative current collector.

[0008] The negative electrode current collector has a blank area without negative electrode active material, and part of the blank area is bent to form an electrode tab. At least one side of the blank area is provided with a groove along the thickness direction of the negative electrode current collector.

[0009] The positive electrode active material on the positive electrode sheet includes ternary materials; among which, the molecular formula of the ternary material is LiNi. x Co y M 1-x-y O2, 0.8≤x<1, 0<y<0.2, M is selected from at least one of Mn and Al;

[0010] An electrolyte, disposed in the shell, comprises a cyclic carbonate solvent and a fluorosulfonamide compound, wherein the cyclic carbonate solvent accounts for less than or equal to 30% by mass in the electrolyte, and the fluorosulfonamide compound accounts for 2%-30% by mass in the electrolyte;

[0011] The collector plate is located in the housing. The side of the collector plate facing the winding core has a contact protrusion, and the electrode lug abuts against the contact protrusion.

[0012] As an alternative implementation, the collector plate is provided with an exhaust notch, and the projection of the exhaust notch at least partially coincides with the projection of the tab along the height direction of the cylindrical battery.

[0013] As an alternative implementation, the projection of the current collector along the height direction of the cylindrical battery is in the shape of a herringbone, a V-shape, or spokes.

[0014] As an optional implementation method,

[0015] The height of the contact protrusion ranges from 0.1mm to 0.5mm; and / or,

[0016] The maximum width of the contact protrusion ranges from 0.5mm to 6mm; and / or,

[0017] The maximum length of the contact protrusion ranges from 3mm to 10mm; and / or,

[0018] There are multiple contact protrusions, and the interval between two adjacent contact protrusions ranges from 0.2mm to 10mm.

[0019] As an optional implementation method,

[0020] The electrode tabs are welded to the collector plate;

[0021] The solder joint between the electrode tab and the collector plate is located on the contact protrusion; and / or,

[0022] The current collector is a one-piece molded part, and the contact protrusion is formed by the indentation of part of the current collector towards the core; and / or, along the thickness direction of the negative electrode current collector, the depth of the groove is 40% to 90% of the thickness of the blank area.

[0023] As an optional implementation method,

[0024] The positive electrode active material also includes doping elements, including at least one selected from Mg, Ti, Nb, Zr, B, W, Al, and P; and / or,

[0025] The positive electrode active material is a mixed structure of single-crystal particles and polycrystalline particles. The mass content of single-crystal particles is C1, and C1 satisfies: 70% ≤ C1 < 100%.

[0026] As an optional implementation, the negative current collector on the negative electrode sheet is copper foil;

[0027] Wherein, the elongation of the negative electrode current collector is ≥10%; and / or,

[0028] The tensile strength of the negative electrode current collector ranges from 300MPa to 800MPa.

[0029] As an alternative implementation, the negative electrode active material on the negative electrode sheet includes graphite and silicon carbon;

[0030] The silicon content of the negative electrode active material ranges from 5% to 50% by mass.

[0031] As an optional implementation, the fluorosulfonamide compound includes one or more of N,N-dimethylaminosulfonyl fluoride, N,N-diethylaminosulfonyl fluoride, N-ethyl-N-methylaminosulfonyl fluoride, N,N-di(fluoromethyl)aminosulfonyl fluoride, N,N-di(difluoromethyl)aminosulfonyl fluoride, N,N-di(trifluoromethyl)aminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide, wherein the fluorosulfonamide compound constitutes 5%-25% by mass in the electrolyte.

[0032] On the other hand, this application provides an electrical device including the aforementioned cylindrical battery.

[0033] The cylindrical battery and electrical device provided in this application have the following advantages:

[0034] 1. By creating grooves in the blank area of ​​the negative electrode sheet, cracks are generated during the bending and flattening process to form the tabs. These cracks are not limited to a single direction; multiple cracks connect to form a network, allowing the electrolyte to flow along the cracks. This effectively improves the wettability of the electrode sheet and enhances the battery's rate performance. Simultaneously, the tab formation in the blank area, i.e., the full tab structure design, also compensates for the insufficient current-carrying capacity caused by the relatively small connection area between the tabs and contact protrusions.

[0035] 2. Contact protrusions are set on the current collector, and the contact protrusions abut against the tabs. This solves the problem of internal damage or weakened current carrying capacity of the tabs caused by grooves. Therefore, the contact protrusions are set to form stable and reliable point or line contact between the tabs and the contact protrusions. By increasing the local contact pressure and optimizing the electron transmission path, the contact resistance and ohmic internal resistance between the current collector and the tabs are effectively reduced, so that the battery can support higher charge and discharge currents and improve rate performance and power output capability.

[0036] 3. At the same time, due to the presence of contact protrusions, there is a gap between the current collector and the core, which provides a small space for the tab to move. When the cell expands during cycling, the tab can undergo micro-sliding or elastic deformation at the contact point, thereby releasing the in-plane tensile stress and avoiding the tab tearing caused by stress concentration. At the same time, the gap between the current collector and the core also provides space for the expansion and micro-displacement of the core.

[0037] 4. Because cyclic carbonate solvents are prone to electrochemical oxidation and decomposition under the high operating voltage of high-nickel cathode materials, resulting in the oxidation of the solvent and the generation of gas, excessive gas production in the battery will affect the rate performance of the battery. Therefore, the mass percentage of cyclic carbonate solvents is limited to less than or equal to 30%.

[0038] 5. Fluorosulfonamide compounds have the advantages of good oxidation resistance and high stability. They can form a protective film on the surface of the active material layer of the negative electrode, inhibiting side reactions between the electrolyte and the negative electrode, reducing high-temperature gas generation, and improving furnace temperature. Therefore, by adding fluorosulfonamide compounds, the high-temperature gas generation of the entire battery cell can be reduced, and the high-temperature rate capability can be improved. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a partially exploded structural diagram of a cylindrical battery provided in an embodiment of this application;

[0041] Figure 2 for Figure 1 One of the schematic diagrams of the current collector of the cylindrical battery shown;

[0042] Figure 3 for Figure 1 The second schematic diagram of the current collector of the cylindrical battery shown;

[0043] Figure 4 for Figure 2 A cross-sectional view of the collector plate shown;

[0044] Figure 5 This is a schematic diagram of the negative electrode sheet provided in an embodiment of this application.

[0045] Explanation of reference numerals in the attached figures:

[0046] 100-Cylindrical battery; 10-Casing; 20-Coil core; 30-Current collector; 32-Contact protrusion; 33-Ventilation notch; 1-Negative electrode sheet; 11-Negative electrode active material; 12-Blank area; 121-Groove. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0048] With the increasing demands for range in new energy vehicles and energy storage systems, improving battery energy density and pursuing high-rate discharge have become core directions for industry development. Currently, cylindrical batteries mostly use high-nickel ternary cathode materials. However, while these materials offer high specific capacity, they are also prone to gas generation during high-temperature cycling, causing battery swelling. If a current collector with non-fully covered tabs is used to alleviate gas generation, it reduces the stable and effective contact between the current collector and the tabs, leading to increased battery impedance. Furthermore, insufficient wettability of the electrode sheets during high-rate charge and discharge can also affect the battery's rate performance.

[0049] To overcome the shortcomings of existing technologies, after repeated consideration and verification, the inventors discovered that by setting blank areas on the negative electrode sheet, and by creating a mesh-like crack pattern in these blank areas through grooves, the electrolyte wettability of the negative electrode sheet can be improved. Furthermore, by setting contact protrusions on the current collector to abut and connect with the tabs, the internal damage or weakened current-carrying capacity of the tabs caused by the grooves can be resolved. In addition, the tabs and current collector can form point / line contact, increasing contact pressure, shortening the electron transport path, significantly reducing ohmic resistance, and improving rate performance. Finally, by controlling the content of cyclic carbonate solvents and fluorosulfonamide compounds in the electrolyte, side reactions and gas generation between the electrolyte and the electrode sheet can be avoided, preventing the battery from achieving high energy density and high rate performance.

[0050] In view of this, this application provides a cylindrical battery, comprising:

[0051] A core, disposed within a housing, includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a positive current collector and a positive active material disposed on the positive current collector. The negative electrode sheet includes a negative current collector and a negative active material disposed on the negative current collector. The negative current collector has a blank area without negative active material, and part of the blank area is bent to form an electrode tab. At least one side of the blank area has a groove along the thickness direction of the negative current collector. The positive active material on the positive electrode sheet includes a ternary material; wherein the molecular formula of the ternary material is LiNi. x Co y M 1-x-yO2, 0.8≤x<1, 0<y<0.2, M is selected from at least one of Mn and Al;

[0052] An electrolyte, disposed in the shell, comprises a cyclic carbonate solvent and a fluorosulfonamide compound, wherein the cyclic carbonate solvent accounts for less than or equal to 30% by mass in the electrolyte, and the fluorosulfonamide compound accounts for 2%-30% by mass in the electrolyte;

[0053] The collector plate is located in the housing. The side of the collector plate facing the winding core has a contact protrusion, and the electrode lug abuts against the contact protrusion.

[0054] By incorporating contact protrusions on the current collector, a stable and reliable point or line contact is formed between the protrusions and the tabs due to their abutting connection. This increases local contact pressure and optimizes the electron transport path, effectively reducing the contact resistance and ohmic internal resistance between the current collector and the tabs. This allows the battery to support higher charge and discharge currents, improving rate performance and power output. Simultaneously, the presence of contact protrusions creates a gap between the current collector and the winding core, providing a small space for the tabs to move. When the cell expands during cycling, the tabs can undergo micro-sliding or elastic deformation at the contact point, releasing in-plane tensile stress and preventing tab tearing caused by stress concentration. The gap between the current collector and the winding core also provides space for the expansion and minor displacement of the winding core.

[0055] The contents of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the contents of this application.

[0056] The following sections provide a detailed description of the specific structure of the cylindrical battery and various possible implementation methods.

[0057] like Figure 1 As shown in the embodiment of this application, the cylindrical battery 100 is used in electrical equipment.

[0058] The cylindrical battery 100 includes a casing 10, a winding core 20, an electrolyte, and a current collector 30. The winding core 20, the electrolyte, and the current collector 30 are respectively disposed in the casing 10. The winding core 20 includes a positive electrode sheet, a negative electrode sheet, and a separator. The winding core 20 has tabs.

[0059] like Figure 2 , Figure 3 and Figure 4 As shown, the collector plate 30 has a contact protrusion 32 on the side facing the winding core 20. The electrode lug abuts against the contact protrusion 32.

[0060] The positive electrode sheet includes a positive current collector and a positive active material disposed on the positive current collector, and the negative electrode sheet 1 includes a negative current collector and a negative active material disposed on the negative current collector.

[0061] By providing contact protrusions 32 on the current collector 30, and through the abutment connection between the contact protrusions 32 and the tabs, a stable and reliable point or line contact is formed between the tabs and the contact protrusions 32. By increasing the local contact pressure and optimizing the electron transport path, the contact resistance and ohmic internal resistance between the current collector 30 and the tabs are effectively reduced, enabling the battery to support higher charge and discharge currents and improving rate performance and power output. Simultaneously, the presence of contact protrusions creates a gap between the current collector and the winding core, providing a small space for the tabs to move. When the cell expands during cycling, the tabs can undergo micro-sliding or elastic deformation at the contact point, thereby releasing in-plane tensile stress and preventing tab tearing caused by stress concentration. The gap between the current collector and the winding core also provides space for the expansion and slight displacement of the winding core. Combined with the overall rigidity of the current collector 30, radial support is provided for the cell, resisting its reciprocating expansion and contraction, preventing the collapse of the internal structure of the cell, and thus extending the battery's cycle life. Moreover, the manifold 30 structure can be formed in one step through mature processes such as stamping and etching, without the need for additional complex production steps or materials. It has good process compatibility and cost advantages, making it easy to carry out large-scale production applications.

[0062] like Figure 5 The negative electrode current collector has a blank area 12 without negative electrode active material 11. Part of the blank area 12 is bent to form an electrode tab. At least one side of the blank area 12 has a groove 121 along the thickness direction of the negative electrode current collector. The electrode tab formed by bending the blank area 12 can be formed by a flattening process. During the flattening operation, the blank area is subjected to extrusion pressure. During the extrusion process, cracks are generated at the edge of the groove 121, and the cracks are not limited to a single direction. Multiple cracks are connected to form a network. During the electrolyte injection process, the electrolyte can flow along the cracks, thereby effectively improving the electrolyte injection efficiency and electrode wettability. The groove 121 can be formed on the negative electrode current collector by laser.

[0063] The electrolyte comprises a cyclic carbonate solvent and a fluorosulfonamide compound, wherein the cyclic carbonate solvent accounts for less than or equal to 30% by mass in the electrolyte, and the fluorosulfonamide compound accounts for 2%-30% by mass in the electrolyte.

[0064] Fluorosulfonamide compounds include one or more of N,N-dimethylaminosulfonyl fluoride, N,N-diethylaminosulfonyl fluoride, N-ethyl-N-methylaminosulfonyl fluoride, N,N-di(fluoromethyl)aminosulfonyl fluoride, N,N-di(difluoromethyl)aminosulfonyl fluoride, N,N-di(trifluoromethyl)aminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide, wherein the fluorosulfonamide compound constitutes 5%-25% by mass in the electrolyte.

[0065] Fluorosulfonamide compounds possess advantages such as good oxidation resistance and high stability. They can form a protective film on the surface of the active material layer of the negative electrode, suppressing side reactions between the electrolyte and the negative electrode, reducing high-temperature gas generation, and improving furnace temperature. When the weight content of fluorosulfonamide compounds in the electrolyte is less than 2%, the addition amount of fluorosulfonamide compounds is relatively small, resulting in a weak inhibitory effect on gas generation and heat generation rates, making it difficult to improve the hot box throughput. When the weight content of fluorosulfonamide compounds in the electrolyte is higher than 30%, the addition amount of fluorosulfonamide compounds is relatively high. Due to the high viscosity of fluorosulfonamide compounds, this will affect the lithium-ion kinetics and cycle performance. Further, 5%-25% is preferred.

[0066] The positive electrode active material on the positive electrode sheet includes ternary materials. The molecular formula of the ternary material is LiNi. x Co y M 1-x-y O2, 0.8≤x<1, 0<y<0.2, M is selected from at least one of Mn and Al.

[0067] High nickel content is LiNi x Co y M 1-x-y The characteristics of O2, with its higher nickel content, mean that more lithium ions can be reversibly inserted and extracted under the same material mass or volume. Although it generates more heat during battery cycling, it has the advantage of directly imparting higher specific capacity and volumetric capacity to the battery's positive electrode, achieving high energy density. In this application, the design of the current collector allows the heat generated by the positive electrode material to be dissipated rapidly, thus combining the advantages of high safety and high energy density.

[0068] As an optional implementation, the current collector 30 includes a positive current collector 30 and a negative current collector 30. The positive current collector 30 is electrically connected to the positive electrode of the core 20 via a positive tab. The negative current collector 30 is electrically connected to the negative electrode of the core 20 via a negative tab. The positive and negative tabs are respectively parts of the positive and negative current collectors, and can be formed into a full-tab cylindrical core through a flattening process, and then the tabs are connected to either the positive or negative current collector 30.

[0069] As an optional implementation, the collector plate 30 is provided with an exhaust notch 33. Along the height direction of the cylindrical battery 100, the projection of the exhaust notch 33 at least partially coincides with the projection of the electrode tab.

[0070] By aligning the projection of the venting notch 33 with the projection of the tab, space is reserved to create a directional, low-resistance venting path directly from the tab, the core area of ​​gas generation in the cell, to the battery's pressure relief mechanism. This allows gas generated under abnormal conditions such as high temperature and overcharging to be quickly and orderly guided and released, alleviating internal pressure buildup and effectively suppressing battery swelling, thus improving battery safety and reliability. Actively guiding gas generation through the venting notch 33 reduces mechanical stress fatigue caused by internal pressure changes in high-temperature environments or long-term cycling, helping to maintain the integrity of the casing 10 and internal structure, thereby improving the battery's cycle life and environmental adaptability under harsh conditions.

[0071] Meanwhile, since the electrode tab and the current collector 30 are connected on the contact protrusion, the gas exhaust function and the current collection function are structurally separated. The exhaust notch 33 is specifically responsible for pressure relief, while the current collector 30 focuses on providing a stable electrical connection. This allows for maximizing exhaust efficiency without sacrificing electrical connection performance, achieving decoupling optimization of gas generation mitigation and electrical connection.

[0072] As an alternative implementation, the projection of the current collector 30 along the height direction of the cylindrical battery 100 is in the shape of a herringbone, a V-shape, or a spoke shape.

[0073] The herringbone, V-shaped, or spoke-like design signifies that the current collector 30 itself possesses a truss-like or rib-like reinforcing structure. When the cylindrical battery 100 undergoes radial expansion during cycling, this rigid structure provides mechanical guidance, effectively decomposing and transferring the outward expansion force applied by the core 20 to the robust battery casing 10. This creates a strong, uniform radial constraint on the core 20, resisting its reciprocating expansion and contraction deformation. Through the connection between the current collector 30 and the tabs, it prevents the inner side of the core 20 from collapsing. Simultaneously, the radial support of this rigid structure also suppresses structural relaxation and increased gaps in the core 20 caused by repeated lithium-ion insertion / extraction during long-term charge-discharge cycles. This effectively prevents contact failure between the electrode active material and the current collector, as well as separator wrinkling or localized deformation, thereby maintaining the stability of the ion and electron transport paths and extending the battery's cycle life.

[0074] As an optional implementation, the height of the contact protrusion ranges from 0.1mm to 0.5mm.

[0075] The protrusion height range of 0.1mm-0.5mm ensures sufficient pre-tightening contact force for the tabs without excessive protrusion that could damage the active material layer on the tabs or electrodes. When the tab abuts against the contact protrusion 32, this protrusion height causes a slight elastic deformation of the tab. This deformation significantly increases the local pressure at the contact interface, effectively breaking down the oxide film or impurities on the tab surface, reducing contact resistance, and preventing fatigue or damage to the tab material due to excessive deformation, resulting in a more reasonable stress distribution.

[0076] A protrusion height range of 0.1mm-0.5mm is suitable for one-time forming using a high-precision stamping process. If the depth is less than 0.1mm, the forming effect of the contact protrusion 32 is not obvious, and its improvement effect on the electrode connection is limited; if it is greater than 0.5mm, the material stretching ratio requirement during stamping is too high, which can easily lead to excessive thinning of the substrate of the manifold 30, resulting in microcracks, or require more complex processes, thereby damaging the overall mechanical strength and reliability of the manifold 30.

[0077] As an alternative implementation, the maximum width of the contact protrusion 32 ranges from 0.5mm to 6mm.

[0078] The width range of 0.5mm-6mm creates a tolerant lateral space during assembly, which ensures an effective connection between the tab and the contact protrusion 32. Even if there is a certain assembly deviation between the tab and the collector plate 30 in the width direction or a slight wobbling of the tab itself, it can still ensure that the tab reliably forms an effective contact with the contact protrusion 32, reducing the precision requirements for production assembly and improving production yield and efficiency.

[0079] At the same time, this width provides the necessary lateral deformation space for the tab during cyclic expansion. When cell expansion causes the tab to stretch laterally or bend slightly, sufficient width allows the tab to slide or bend slightly, thereby effectively releasing in-plane stress.

[0080] As an alternative implementation, the maximum length of the contact protrusion 32 ranges from 3mm to 10mm.

[0081] The length range of 3mm-10mm is significantly larger than the contact point size required for the tab to contact the current collector 30. This design ensures that a sufficiently long effective contact line or contact band can be formed between the tab and the contact protrusion 32. The longer contact length facilitates more even current flow from the tab into the current collector 30, avoiding localized overheating caused by excessive current concentration at a single contact point, and improving thermal safety and electrical stability during high-rate charging and discharging. Simultaneously, this length range allows for effective connection of the tab's extended portion. When the battery is subjected to vibration or impact, it prevents excessive swaying or twisting of the tab in the length direction, thereby reducing the risk of tab breakage due to fatigue stress and enhancing the battery's mechanical reliability under dynamic operating conditions.

[0082] As an optional implementation, there are multiple contact protrusions 32, and the interval between two adjacent contact protrusions 32 ranges from 0.2mm to 10mm.

[0083] By setting multiple contact protrusions 32 distributed at specific intervals, multiple parallel current transmission paths are formed between the electrode tab and the current collector 30, which can effectively distribute the total current to each contact point, avoiding excessive current density and local overheating that may be caused by single-point contact. The reasonable spacing ensures that these current paths are fully separated in space, thereby improving the uniformity of current distribution and heat dissipation performance at the contact interface, and enhancing the stability and safety of the battery under high current conditions.

[0084] Multiple spaced contact protrusions 32 jointly bear the mechanical loads applied by the tabs, such as cell expansion force and vibration impact force, effectively dispersing concentrated stress to multiple support points, reducing the stress peak at a single contact point, reducing the risk of plastic deformation or failure at the contact point, and also making the entire connection structure more resistant to mechanical fatigue and more reliable in the long-term cyclic expansion of the battery and vehicle vibration environment.

[0085] The reasonable spacing ensures that even if individual contact protrusions 32 experience slight performance degradation due to minor manufacturing deviations or long-term use, the remaining contact points can still maintain effective connection. This provides redundancy for the electrical connection and reduces the risk of a sudden increase in the overall tab connection resistance or open circuit due to the failure of a single contact point, thereby improving the system-level reliability and long-term consistency of the battery electrical connection.

[0086] As an optional implementation, the electrode tab is welded to the collector plate 30.

[0087] The welding at the contact interface between the electrode tab and the current collector 30 forms a metallurgical bond, eliminating the obstruction to current transmission that may exist in simple mechanical contact due to surface oxide films, contaminants, or micro-gap. This establishes a low-resistance electrical connection, achieving low internal resistance, high power output, and excellent consistency of the battery. The welded connection point has high mechanical strength, effectively resisting the shear forces generated by electrode expansion and contraction during long-term cycling, severe vibrations and impacts during vehicle operation, and possible accidental external compression. This prevents loosening, fretting wear, or detachment between the electrode tab and the current collector 30, ensuring reliable electrical connection throughout the battery's entire lifespan.

[0088] As an optional implementation, the welding point between the electrode tab and the collector plate 30 is located on the contact protrusion 32. Preferably, the collector plate is an integrally formed part, and the contact protrusion 32 is formed by a portion of the collector plate being recessed towards the core.

[0089] The contact protrusion 32 itself is a reinforced structure formed by stamping, and its edges and bottom have higher local rigidity. By setting the weld point on the contact protrusion 32, its three-dimensional structure can effectively resist and disperse the instantaneous thermal stress generated during welding, suppress the spread of the welding heat-affected zone to other areas of the manifold 30 plane, avoid uncontrollable flatness deterioration such as warping and wavy deformation of the manifold 30 as a whole, and ensure the shape accuracy and functional integrity of the manifold 30.

[0090] In some embodiments, the solder joints between the tab and the current collector 30 can be located on the side of the contact protrusion 32 facing away from the core, i.e., the solder joints are positioned away from the tab to prevent the solder joints from forming protrusions. At the same time, the solder joints being positioned away from the tab can limit any possible small spatter or burrs generated during welding to the other side of the current collector, preventing them from causing potential damage to other internal components of the battery (such as the separator), thus improving overall safety and reliability.

[0091] In some embodiments, the depth of the groove 121 along the thickness direction of the negative electrode current collector is 40% to 90% of the thickness of the blank area 12. By limiting the depth of the groove 121, the material failure mode is changed from fracture to controllable cracking. In the subsequent flattening process, the external pressure will preferentially cause controllable plastic deformation and cracking at the bottom of the groove 121, thereby expanding upward or downward to form microcracks.

[0092] If the depth of the groove 121 in this specific embodiment is less than 40% of the thickness of the blank area 12, the remaining thickness of the blank area 12 where the groove 121 is located is relatively thick, resulting in excessively high mechanical strength. During rolling, the stress cannot be effectively concentrated at the bottom of the groove 121, making it difficult to induce the required regular crack network, thus resulting in negligible improvement in electrode wetting. If the depth of the groove 121 in this specific embodiment is greater than 90% of the thickness of the blank area 12, the remaining thickness of the blank area 12 where the groove 121 is located is relatively thin, approaching penetration, resulting in extremely weak load-bearing capacity. Uncontrolled complete breakage may occur during the initial winding tension or rolling stage, generating metal fragments and bringing the risk of micro-short circuits and thermal runaway.

[0093] As an optional implementation, the positive electrode active material also includes a dopant element. The dopant element includes at least one selected from Mg, Ti, Nb, Zr, B, W, Al, and P.

[0094] In the deep delithiation state, high-nickel materials readily transform from an ordered layered structure to a disordered spinel or rock salt phase, accompanied by the release of lattice oxygen and drastic changes in lattice parameters, leading to microcracks within the particles. Dopants possess strong MO bond energies, selectively occupying transition metal or lithium sites to form a stable pillar effect. This effectively suppresses excessive lattice contraction / expansion during cycling, slows down harmful phase transitions, and reduces microcrack formation, thereby maintaining the structural integrity of the active particles.

[0095] As an optional implementation, the positive electrode active material is a mixed structure of single-crystal particles and polycrystalline particles. The mass content of the single-crystal particles is C1. C1 satisfies: 70% ≤ C1 < 100%.

[0096] The design of mixing single-crystal and polycrystalline particles, with a high proportion of single-crystal particles forming a robust and stable skeleton in the electrode, ensures the overall structural durability; while the polycrystalline particles dispersed within act as functional fillers for optimized filling and conduction, avoiding the kinetic limitations that pure single-crystal materials may face and the inherent grain boundary crack problems of pure polycrystalline materials, balancing high capacity and structural stability, reducing gas generation caused by side reactions, and achieving a performance balance.

[0097] By adjusting the ratio of monocrystalline to polycrystalline materials, the lithium-ion diffusion path and resistance to microcracks can be optimized at the material particle level, while suppressing gas generation.

[0098] As an optional implementation, the negative current collector on the negative electrode sheet is copper foil.

[0099] Copper is the second best conductor after silver. Using copper foil as a current collector provides an electron collection and transport path with extremely low resistance for the negative electrode active material layer, which helps to reduce the internal resistance of the entire battery. Especially during high-rate charge and discharge, it can effectively reduce polarization, improve power performance, and reduce heat generation during charge and discharge.

[0100] As an optional implementation, the elongation of the negative electrode current collector is ≥10%.

[0101] As an optional implementation, the tensile strength of the negative electrode current collector ranges from 300MPa to 800MPa.

[0102] High elongation and tensile strength copper foil can better accommodate the volume expansion of the negative electrode material during cycling, reducing the risk of current collector breakage at the welding position of the current collector 30.

[0103] During charging and discharging, especially when using anode materials with significant volume expansion, such as silicon-based materials, the active material layer undergoes periodic expansion and contraction, generating repeated tensile and compressive stresses on the current collector. Copper foil with an elongation of ≥10% possesses sufficient elasticity and plastic deformation capacity, enabling it to absorb and buffer this stress through minute, controllable stretching. This reduces interfacial delamination between the current collector and the active material layer caused by deformation incompatibility, maintaining good electrical contact. It also reduces the risk of fatigue fracture of the current collector itself, preventing the failure of some active materials due to current collector fracture, thereby ensuring the long-term cycle life of the battery.

[0104] Tensile strength and elongation are interrelated; this combination of strength and toughness ensures structural stability and constraint on the active material, preventing brittle fracture and adapting to deformation during manufacturing and use. This enables the current collector to achieve high lifespan and reliability under the complex stress environment of the battery.

[0105] As an alternative implementation, the negative electrode active material on the negative electrode sheet includes graphite and silicon carbon.

[0106] As an optional implementation method, the silicon element accounts for 5%-50% of the mass content of the negative electrode active material.

[0107] Incorporating silicon-carbon materials into graphite anodes can significantly improve the overall average specific capacity of the anode, thereby directly and effectively increasing the energy density of the battery.

[0108] Setting the lower limit for silicon at 5% ensures that its introduction delivers a clear and substantial increase in energy density. Setting the upper limit for silicon at 50% aims to keep the negative impacts of silicon within a range that can be effectively managed by existing material systems and manufacturing processes, ensuring that the battery possesses acceptable cycle life, safety, and commercial viability.

[0109] As an optional implementation, the cyclic carbonate solvent has a mass percentage of less than or equal to 30% in the electrolyte.

[0110] Cyclic carbonates, such as ethylene carbonate (EC), propylene carbonate (PC), or mixtures thereof, exhibit relatively poor oxidation stability, particularly at high operating voltages in high-nickel cathode materials, where they are prone to electrochemical oxidation and decomposition. Strictly controlling their content to ≤30% reduces the number of unstable solvent molecules available for oxidation at the cathode / electrolyte interface, effectively reducing continuous electrolyte decomposition and consumption at high potentials, slowing capacity decay, suppressing gas generation due to solvent oxidation, alleviating battery swelling issues, and improving long-term cycle and storage stability. Cyclic carbonates (especially ethylene carbonate) have relatively limited thermal stability at high temperatures; their decomposition may initiate or participate in chain exothermic reactions. Reducing their proportion in the electrolyte directly lowers the overall reactivity of the electrolyte system under high-temperature and overcharge conditions, helping to improve battery thermal stability, delaying thermal runaway, and providing a wider safety window for the battery management system.

[0111] It should be noted that the following are the processes for preparing cylindrical batteries 100 in multiple embodiments and comparative examples.

[0112] Example 1

[0113] Positive electrode preparation: The positive electrode active material LiNi is prepared... 0.8 Co 0.1 Mn 0.1 O2 (NCM811), conductive agent Super P, and binder PVDF are mixed at a mass ratio of 96.5:2.0:1.5. N-methylpyrrolidone (NMP) is added and stirred to form a uniform slurry. This slurry is then coated onto both sides of a 10μm thick aluminum foil. After drying and rolling, the positive electrode sheet is obtained. The positive electrode active material is doped with Al: 800ppm, Zr: 1800ppm, B: 1000ppm, and W: 860ppm. The positive electrode active material adopts a mixed structure of single-crystal and polycrystalline particles, with single-crystal particles accounting for 80% by mass and polycrystalline particles accounting for 20% by mass.

[0114] Negative electrode preparation: The negative electrode active material (a mixture of graphite and silicon carbon, wherein silicon carbon accounts for 50% by mass and silicon accounts for 10% by mass of the negative electrode active material), conductive carbon black, CMC, and SBR are mixed in a mass ratio of 94.5:1.5:1.5:2.5, deionized water is added and stirred into a slurry, which is then coated on both sides of an 8μm thick copper foil. After drying and rolling, the negative electrode is obtained. The high-ductility electrolytic copper foil has an elongation of 12% and a tensile strength of 350MPa. The blank area of ​​the negative electrode current collector is obtained by laser wire cutting to create a groove with a thickness of 60% of the negative electrode current collector.

[0115] Electrolyte preparation: In an argon-atmospheric glove box with a water content of <10ppm, LiPF6 was dissolved in a mixed solvent (ethylene carbonate EC: propylene carbonate PC: methyl ethyl carbonate EMC = 1:1:2, volume ratio), and 2% fluoroethylene carbonate (FEC) was added as an additive. Then, 20% N,N-dimethylaminosulfonyl fluoride was added, and the mixture was stirred until homogeneous to obtain the electrolyte. The concentration of LiPF6 was 1.2 mol / L, and the total mass percentage of cyclic carbonate solvent (EC+PC) in the electrolyte was 25%.

[0116] Fabrication of the current collector 30: The positive current collector 30 is made of aluminum by stamping and has an overall herringbone (spoke) structure. The current collector 30 has contact protrusions facing the tab, with a height H = 0.3 mm, width W = 3.0 mm, and length L = 6.0 mm. The contact protrusions are used to form point / line contact with the tab.

[0117] Negative current collector 30: It is made of copper material by stamping, and also has a herringbone structure, and has contact protrusions of the same size.

[0118] The collector plate 30 adopts a design that does not completely cover the electrode tab, that is, a directional exhaust channel is reserved between the collector plate 30 and the electrode tab.

[0119] Cell Assembly: The positive electrode sheet, negative electrode sheet, and separator are wound into a 21700 specification core 20. The positive current collector 30 and negative current collector 30 are welded on respectively, ensuring that the welding points are located on the contact protrusions. The core 20 is placed into the steel casing 10, electrolyte is injected, and the casing is sealed with a cap equipped with an explosion-proof valve. After formation and capacity testing, a 21700 cylindrical battery 100 is obtained.

[0120] Example 2

[0121] The difference between Example 2 and Example 1 is that the height H of the contact protrusion is 0.1 mm, the width W is 6 mm, and the length L is 3 mm. The rest of the structure is the same as in Example 1.

[0122] Example 3

[0123] The difference between Example 3 and Example 1 is that the height H of the contact protrusion is 0.5 mm, the width W is 0.5 mm, and the length L is 10 mm. The rest of the structure is the same as in Example 1.

[0124] Example 4

[0125] The difference between Example 4 and Example 1 is that the positive electrode active material in Example 4 is doped with Mg: 1000ppm, Ti: 800ppm, Nb: 500ppm, and P: 600ppm. The rest of the structure is the same as in Example 1.

[0126] Example 5

[0127] The difference between Example 5 and Example 1 is that the positive electrode active material is a mixed structure of single-crystal particles and polycrystalline particles, with the mass content of single-crystal particles being 70% and the mass content of polycrystalline particles being 30%. The remaining structure is the same as in Example 1.

[0128] Example 6

[0129] The difference between Example 6 and Example 1 is that the positive electrode active material is a mixed structure of single-crystal particles and polycrystalline particles, with the mass content of single-crystal particles being 75% and the mass content of polycrystalline particles being 25%. The remaining structure is the same as in Example 1.

[0130] Example 7

[0131] The difference between Example 7 and Example 1 is that the positive electrode active material is a mixed structure of single-crystal particles and polycrystalline particles, with the mass content of single-crystal particles being 85% and the mass content of polycrystalline particles being 15%. The remaining structure is the same as in Example 1.

[0132] Example 8

[0133] The difference between Example 8 and Example 1 is that the positive electrode active material is a mixed structure of single-crystal particles and polycrystalline particles, with the mass content of single-crystal particles being 90% and the mass content of polycrystalline particles being 10%. The remaining structure is the same as in Example 1.

[0134] Example 9

[0135] The difference between Example 9 and Example 1 is that silicon accounts for 5% of the mass of the negative electrode active material. The rest of the structure is the same as in Example 1.

[0136] Example 10

[0137] The difference between Example 10 and Example 1 is that the cyclic carbonate solvent accounts for 30% by mass in the electrolyte. The rest of the structure is the same as in Example 1.

[0138] Example 11

[0139] The difference between Example 11 and Example 1 is that the thickness of the groove is 30% of the thickness of the negative electrode current collector. The rest of the structure is the same as in Example 1.

[0140] Example 12

[0141] The difference between Example 12 and Example 1 is that the thickness of the groove is 95% of the thickness of the negative electrode current collector. The rest of the structure is the same as in Example 1.

[0142] Example 13

[0143] The difference between Example 13 and Example 1 is that the mass percentage of N,N-dimethylaminosulfonyl fluoride is 2%. The rest of the structure is the same as that of Example 1.

[0144] Example 14

[0145] The difference between Example 14 and Example 1 is that the mass percentage of N,N-dimethylaminosulfonyl fluoride is 30%. The rest of the structure is the same as in Example 1.

[0146] Example 15

[0147] The difference between Example 15 and Example 1 is that N,N-dimethylaminosulfonyl fluoride is replaced with N-ethyl-N-methylaminosulfonyl fluoride. The rest of the structure is the same as in Example 1.

[0148] Comparative Example 1

[0149] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 features a non-contact protrusion structure design. The rest of the structure is the same as that of Example 1.

[0150] Comparative Example 2

[0151] The difference between Comparative Example 2 and Example 1 is that the height H of the contact protrusion is 0.05 mm, the width W is 0.3 mm, and the length L is 2 mm. The rest of the structure is the same as that of Example 1.

[0152] Comparative Example 3

[0153] The difference between Comparative Example 3 and Example 1 is that the height H of the contact protrusion is 0.6 mm, the width W is 8 mm, and the length L is 12 mm. The rest of the structure is the same as that of Example 1.

[0154] Comparative Example 4

[0155] The difference between Comparative Example 4 and Example 1 is that the cyclic carbonate solvent accounts for 60% by mass in the electrolyte. The rest of the structure is the same as in Example 1.

[0156] Comparative Example 5

[0157] The difference between Comparative Example 5 and Example 1 is that the positive electrode active material is polycrystalline particles, that is, the mass content of polycrystalline particles is 100%. The rest of the structure is the same as that of Example 1.

[0158] Comparative Example 6

[0159] The difference between Comparative Example 6 and Example 1 is that the blank area of ​​the negative electrode current collector does not have a groove. The rest of the structure is the same as that of Example 1.

[0160] Comparative Example 7

[0161] The difference between Comparative Example 7 and Example 1 is that N,N-dimethylaminosulfonyl fluoride was not added.

[0162] Comparative tests were conducted on high-temperature gas production, rate performance, and cycle performance.

[0163] The specific testing method for high-temperature gas generation is as follows:

[0164] The battery cells were placed in an environment of 25℃±2℃ and charged to 4.2V with a constant current and constant voltage of 1C. The cutoff current was 0.05C. After being fully charged, the batteries were stored in an environment of 85℃ for 7 days. The explosion-proof valve was observed to see if it opened. The opening rate of the explosion-proof valve was calculated. 15 batteries from the same batch were tested, and the opening rate was calculated (number of open batteries / number of tested batteries).

[0165] The specific testing method for rate performance is as follows:

[0166] At 25℃, the capacitor is charged to 4.2V at a constant current and constant voltage of 0.2C, and then discharged at 0.2C and 3C respectively. Calculate the retention rate of the 3C discharge capacity relative to the 0.2C discharge capacity.

[0167] The specific testing method for cycle performance is as follows:

[0168] The battery cell was placed in an environment of 25℃±2℃ and charged to 4.2V with a constant current and constant voltage of 1C and a cutoff current of 0.05C. After being fully charged, it was left to stand for 10 minutes and then discharged with a constant current of 5C to the cutoff voltage of 2.5V. Three complete charge-discharge cycles were performed, and the discharge capacity of the third cycle was taken as the initial capacity C1.

[0169] Under an environment of 25℃±2℃, continue to cycle according to the charge and discharge regime of step 1 (1C charge / 5C discharge); when the number of cycles reaches 800, stop the test and record the discharge capacity of the 800th cycle as C2.

[0170] Capacity retention rate = (C2 / C1) × 100%.

[0171] The test results are shown in Table 1.

[0172] Table 1. High-temperature gas production, rate performance, and cycle performance data for the examples and comparative examples.

[0173]

[0174] This application also provides an electrical device, including the cylindrical battery 100 described above.

[0175] Since the electrical device in this embodiment includes the cylindrical battery 100 described in any of the above embodiments, the structure and beneficial effects of the electrical device including the cylindrical battery 100 will not be described in detail here.

[0176] The technology is not limited to laptops and tablets; it may be applied to other electronic devices in the future.

[0177] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0178] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0179] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on something” but also “on something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0180] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended 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. Such 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.

Claims

1. A cylindrical battery, characterized in that, include: case; A core is disposed in the housing. The core includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a positive current collector and a positive active material disposed on the positive current collector. The negative electrode sheet includes a negative current collector and a negative active material disposed on the negative current collector. The negative electrode current collector has a blank area where no negative electrode active material is provided, and part of the blank area is bent to form an electrode tab. The blank area has a groove along the thickness direction of the negative electrode current collector on at least one side. The positive electrode active material on the positive electrode sheet includes a ternary material; wherein the molecular formula of the ternary material is LiNi. x Co y M 1-x-y O2, 0.8≤x<1, 0<y<0.2, M is selected from at least one of Mn and Al; An electrolyte is disposed in the shell, the electrolyte comprising a cyclic carbonate solvent and a fluorosulfonamide compound, wherein the cyclic carbonate solvent comprises less than or equal to 30% by mass in the electrolyte, and the fluorosulfonamide compound comprises 2%-30% by mass in the electrolyte; A collector plate is disposed in the housing. The collector plate has a contact protrusion on the side facing the winding core, and the electrode lug abuts against the contact protrusion.

2. The cylindrical battery according to claim 1, characterized in that, The collector plate has an exhaust notch, and the projection of the exhaust notch along the height direction of the cylindrical battery at least partially overlaps with the projection of the tab.

3. The cylindrical battery according to claim 1, characterized in that, Projecting along the height direction of the cylindrical battery, the projection of the current collector is in the shape of a herringbone, a V-shape, or spokes.

4. The cylindrical battery according to claim 1, characterized in that, The height of the contact protrusion ranges from 0.1mm to 0.5mm; and / or, The maximum width of the contact protrusion ranges from 0.5mm to 6mm; and / or, The maximum length of the contact protrusion is 3mm-10mm; and / or, There are multiple contact protrusions, and the interval between two adjacent contact protrusions is 0.2mm-10mm.

5. The cylindrical battery according to claim 1, characterized in that, The electrode tab is welded to the collector plate; Wherein, the solder joint between the electrode tab and the current collector is located on the contact protrusion; and / or, The collector plate is a one-piece molded part, and the contact protrusion is formed by a portion of the collector plate being recessed towards the core; and / or Along the thickness direction of the negative electrode current collector, the depth of the groove is 40% to 90% of the thickness of the blank area.

6. The cylindrical battery according to claim 1, characterized in that, The positive electrode active material further includes doping elements, wherein the doping elements include at least one selected from Mg, Ti, Nb, Zr, B, W, Al, and P; and / or, The positive electrode active material is a mixed structure of single crystal particles and polycrystalline particles, and the mass content of the single crystal particles is C1, wherein C1 satisfies: 70% ≤ C1 < 100%.

7. The cylindrical battery according to claim 1, characterized in that, The negative electrode current collector on the negative electrode sheet is a copper foil; Wherein, the elongation of the negative electrode current collector is ≥10%; and / or, The tensile strength of the negative electrode current collector ranges from 300MPa to 800MPa.

8. The cylindrical battery according to claim 1, characterized in that, The negative electrode active material on the negative electrode sheet includes graphite and silicon carbon; The silicon element accounts for 5%-50% of the mass content of the negative electrode active material.

9. The cylindrical battery according to claim 1, characterized in that, The fluorosulfonamide compounds include one or more of N,N-dimethylaminosulfonyl fluoride, N,N-diethylaminosulfonyl fluoride, N-ethyl-N-methylaminosulfonyl fluoride, N,N-di(fluoromethyl)aminosulfonyl fluoride, N,N-di(difluoromethyl)aminosulfonyl fluoride, N,N-di(trifluoromethyl)aminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide, wherein the mass percentage of the fluorosulfonamide compounds in the electrolyte is 5%-25%.

10. An electrical appliance, characterized in that, Including the cylindrical battery as described in any one of claims 1-9.

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