Pouch cylindrical battery and electrical apparatus

Abstract

In order to overcome the problem that existing pouch batteries are prone to deformation when subjected to large external forces and thus exhibit low safety, the present invention provides a pouch cylindrical battery, comprising a jelly roll. The jelly roll comprises a positive electrode sheet, a separator and a negative electrode sheet. The negative electrode sheet comprises a negative electrode current collector and negative electrode active material layers arranged on the surfaces of the negative electrode current collector, the sum of the thicknesses of the negative electrode active material layers being 12 μm-20 μm. The negative electrode active material layers each comprise a negative electrode silicon-based active material, the negative electrode silicon-based active material comprising pure silicon particles. A first end of the jelly roll is provided with a positive tab, and a second end of the jelly roll is provided with a negative tab, in the axial direction of the jelly roll, the projection of the positive tab on the end surface of the second end of the jelly roll not intersecting the negative tab. In the present invention, because the positive tab and the negative tab are not on the same straight line, when the jelly roll is subjected to a large external force, the same deformation will not generate a large reaction force, and the positive and negative tabs and the positive and negative electrode sheets are less prone to be in contact with each other, such that the jelly roll is less prone to fire or explosion, improving the safety of jelly rolls used in batches.

Description

A soft-pack cylindrical battery and its power application device

[0001] This application claims priority to Chinese Patent Application No. 202411894216.7, filed on December 20, 2024, entitled "A Soft-Pack Cylindrical Battery and an Electrical Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of battery technology, specifically to a soft-pack cylindrical battery and an electrical device thereof. Background Technology

[0003] Lithium-ion batteries, with their advantages of high energy density, long cycle life, and small volume-to-weight ratio, have become the ideal power source for portable electronic devices such as e-cigarettes. In recent years, with the continuous development of the e-cigarette market, consumers' expectations for e-cigarettes have also been constantly upgrading. They not only pursue long battery life, but also have increasingly higher demands for cell energy density, and the same is true in the field of pouch cells.

[0004] However, as the energy density of pouch cylindrical cells increases, the safety and reliability of the cells also deteriorate. If the original conventional cell structure design is still used, its safety and reliability cannot meet industry requirements. This is also a major bottleneck that limits the improvement of energy density in the field of pouch cylindrical cells.

[0005] As shown in Figure 1, in existing technology, the positive and negative tabs of a pouch battery are located at both ends of the winding core, with the extension line of the positive tab coinciding with that of the negative tab along the length of the winding core. When a large external force (e.g., ≥13KN) is applied to the surface of the winding core, the core will undergo significant deformation. Since the positive and negative tabs are located on the same straight line, they are prone to contact with the positive and negative electrode plates when the core undergoes significant deformation, potentially leading to fire or explosion of the winding core, posing a hidden danger to its mass application. Therefore, overcoming the aforementioned technical problems and defects is a key issue that needs to be addressed. Summary of the Invention

[0006] To address the problems of low energy density, easy deformation under large external forces, and low safety of existing pouch batteries, this invention provides a pouch cylindrical battery and an electrical device.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] The present invention provides a soft-pack cylindrical battery, comprising a soft-pack casing and a core disposed within the soft-pack casing, wherein the core comprises a positive electrode sheet, a separator, and a negative electrode sheet;

[0009] The negative electrode sheet includes a negative electrode current collector and negative electrode active material layers disposed on both sides of the surface of the negative electrode current collector, wherein the total thickness of the negative electrode active material layers is 12μm-20μm.

[0010] The negative electrode active material layer includes a negative electrode silicon-based active material, which includes pure silicon particles, and the pure silicon particles have a mass percentage content of 65-100% in the negative electrode silicon-based active material.

[0011] The positive electrode sheet, the separator, and the negative electrode sheet are stacked and wound together to form the core. The positive electrode sheet and the negative electrode sheet are separated by the separator in the core. The positive electrode sheet is provided with a positive electrode tab located at the first end of the core. The negative electrode sheet is provided with a negative electrode tab located at the second end of the core. The projection of the positive electrode tab along the axial direction of the core onto the second end face of the core does not intersect with the projection of the negative electrode tab along the axial direction of the core onto the second end face of the core.

[0012] Optionally, the thickness of the negative electrode sheet is 18μm-28μm.

[0013] Optionally, the areal density of the negative electrode is 1.6-2.4 mg / cm³. 2 The compaction density of the negative electrode sheet is 1.1-1.3 g / cm³. 3 .

[0014] Optionally, the projection of the positive electrode tab along the axial direction of the core onto the second end face of the core and the projection of the negative electrode tab along the axial direction of the core onto the second end face of the core are respectively located on both sides of the central axis of the core, and the positive electrode tab and the negative electrode tab are arranged parallel to each other.

[0015] Optionally, the projections of the positive electrode tab along the axial direction of the core onto the second end face of the core and the projections of the negative electrode tab along the axial direction of the core onto the second end face of the core are symmetrically arranged about the central axis of the core.

[0016] Optionally, the projection of the positive electrode on the separator is located inside the projection of the negative electrode on the separator.

[0017] Optionally, the positive electrode tab is welded to the first end of the positive electrode sheet in the width direction.

[0018] Optionally, the negative electrode tab is welded to one end of the negative electrode sheet away from the positive electrode tab in the width direction.

[0019] Optionally, the area where the positive electrode tab is welded to the positive electrode sheet is called the positive electrode tab welding area. The length of the positive electrode tab welding area is L1 mm, and the width of the positive electrode sheet is W mm. The L1 and W satisfy the relationship: L1 < 1 / 2W.

[0020] Optionally, the area where the negative electrode tab is welded to the negative electrode sheet is called the negative electrode tab welding area, and the length of the negative electrode tab welding area projected onto the positive electrode sheet is L2 mm. The relationship between L2 and W is: L2 < 1 / 2W.

[0021] Optionally, L1, L2, and W satisfy the relationship: L1 + L2 < W - 2.

[0022] In another aspect, the present invention provides an electrical device comprising a pouch-type cylindrical battery as described above.

[0023] According to the core provided by the present invention, by using silicon-based active material as the negative electrode, the energy density of the cell is increased by more than 50% compared with that of graphite, and the battery energy density is significantly improved. At the same time, the positive and negative tabs are set at both ends of the core, and since the positive and negative tabs are not on the same straight line, when a large external force (e.g., ≥13KN) is applied to the surface of the core, the positive and negative tabs are not easy to contact when the core undergoes large axial deformation, thus making it less likely for the core to catch fire or explode, thereby improving the safety of the core in mass application. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the structure of a prior art pouch cylindrical battery;

[0025] Figure 2 is a schematic diagram of the structure of a soft-pack cylindrical battery provided in an embodiment of the present invention;

[0026] Figure 3 is a schematic diagram of the unfolded pouch cylindrical battery provided in an embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of the structure of the negative electrode sheet in a soft-pack cylindrical battery provided in an embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of the first structure of a soft-pack cylindrical battery provided by an embodiment of the present invention, in which the positive electrode tab is welded onto the positive electrode sheet.

[0029] Figure 6 is a schematic diagram of a second structure in which the positive electrode tab is welded onto the positive electrode sheet in a soft-pack cylindrical battery according to an embodiment of the present invention.

[0030] Figure 7 is a schematic diagram of a third structure in which the positive electrode tab is welded onto the positive electrode sheet in a soft-pack cylindrical battery according to an embodiment of the present invention.

[0031] Figure 8 is a schematic diagram of the region partitioning on the electrode sheet in a soft-pack cylindrical battery provided by an embodiment of the present invention;

[0032] The reference numerals in the accompanying drawings are as follows:

[0033] 1-Positive electrode sheet; 11-Positive electrode tab; 2-Negative electrode sheet; 21-Negative electrode current collector; 22-Negative electrode active material layer; 23-Negative electrode tab; 3-Separator. Detailed Implementation

[0034] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] In the description of this invention, it should be understood that the terms "side," "inner," "outer," etc., indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0038] As shown in Figures 2-4, in one embodiment, the present invention provides a soft-pack cylindrical battery, including a soft-pack casing (not shown in the figures) and a core disposed within the soft-pack casing. The core includes a positive electrode 1, a separator 3, and a negative electrode 2.

[0039] The negative electrode sheet 2 includes a negative electrode current collector 21 and negative electrode active material layers 22 disposed on both sides of the surface of the negative electrode current collector 21. The total thickness of the negative electrode active material layers 22 is 12μm-20μm.

[0040] The negative electrode active material layer 22 includes a negative electrode silicon-based active material, which includes pure silicon particles, and the mass percentage of pure silicon particles in the negative electrode silicon-based active material is 65-100%.

[0041] A positive electrode 1, a separator 3, and a negative electrode 2 are stacked and wound together to form a core. The positive electrode 1 and the negative electrode 2 are separated by the separator 3 in the core. A positive electrode tab 11 is provided on the positive electrode 1, which is located at the first end of the core. A negative electrode tab 12 is provided on the negative electrode 2, which is located at the second end of the core. The projection of the positive electrode tab 11 along the axis of the core onto the second end face of the core does not intersect with the projection of the negative electrode tab 12 along the axis of the core onto the second end face of the core.

[0042] Specifically, in one embodiment, negative electrode active material layers 22 are provided on both sides of the surface of the negative electrode current collector 21, and the total thickness of the negative electrode active material layers 22 is 12μm-20μm.

[0043] To better control the stability of the negative electrode silicon-based active material on the negative electrode current collector 21 during battery operation and to improve the conductivity of the negative electrode silicon-based active material, the negative electrode silicon-based active material disposed on one side of the negative electrode current collector 21 in this invention is defined as the first negative electrode active material layer, and the negative electrode silicon-based active material disposed on the other side is defined as the second negative electrode active material layer. The sum of the thicknesses of these active material layers 22 is 12μm-20μm, that is, the sum of the thicknesses of the first negative electrode active material layer and the second negative electrode active material layer is 12μm-20μm. In other words, the thickness of the first negative electrode active material layer is 6μm-10μm, and the thickness of the second negative electrode active material layer is 6μm-10μm. By controlling the sum of the thicknesses of the first and second negative electrode active material layers on the negative electrode 2 to be between 12μm and 20μm, the thickness of the negative electrode 2 is much smaller than that of a conventional negative electrode 2.

[0044] Furthermore, the thickness of the negative electrode silicon-based active material disposed on the negative electrode active material layer on both sides of the negative electrode current collector 21 provided by the present invention can be the same or different. The thickness of the negative electrode silicon-based active material on one side of the negative electrode active material layer can be adjusted separately as needed, or the thickness of the negative electrode silicon-based active material on both sides can be adjusted separately, but the sum of the thicknesses of the negative electrode active material layers 22 on both sides is still controlled between 12μm and 20μm.

[0045] In order to better control the stability of the negative electrode silicon-based active material on the negative electrode current collector 21 during battery operation and improve the conductivity of the negative electrode silicon-based active material, the negative electrode sheet 2 in this invention is provided with negative electrode active material layers 22 on both sides. The sum of the thicknesses of the negative electrode active material layers 22 on both sides is controlled between 12μm and 20μm, so that the thickness of the negative electrode sheet 2 is much smaller than that of the traditional negative electrode sheet 2.

[0046] Specifically, the mass percentage of pure silicon particles in the negative electrode silicon-based active material is any value or a range of any two values ​​from 65%, 75%, 85%, 95%, or 100%. However, it is important to note that 100% pure silicon is only discussed as a theoretical limit. In practical applications, because pure silicon is rarely completely free of impurities in its natural state, the so-called "100% pure silicon" does not actually exist. Even after highly refined processes, silicon materials will still contain trace amounts of impurity elements such as iron, aluminum, and calcium.

[0047] The silicon-based anode active material provided by this invention can be pure silicon, pure silicon and graphite, pure silicon and silicon-carbon materials, or silicon composite materials. When the silicon-based anode active material is pure silicon and graphite, pure silicon and silicon-carbon materials, or silicon composite materials, the mass percentage of pure silicon in the silicon-based anode active material is controlled at 65-100%. By selecting an anode active material containing pure silicon particles, this invention achieves a very high theoretical specific capacity (up to 4200 mAh / g), far exceeding the theoretical specific capacity of traditional graphite anodes (372 mAh / g). Therefore, using an anode active material containing pure silicon particles can significantly improve the energy density of the battery, enabling the battery to store more energy with the same weight or volume. Furthermore, compared to other high-performance anode materials, pure silicon particles have a relatively low cost, giving them a potential cost advantage in large-scale commercial applications.

[0048] Using silicon-based active materials as the negative electrode increases the energy density of the battery cell by more than 50% compared to graphite. However, higher battery energy density leads to poorer battery safety performance. Therefore, this application improves the existing battery structure to enhance battery safety performance.

[0049] As shown in Figure 1, in the prior art, the positive tab 11 and negative tab 23 of the soft-pack cylindrical battery are located at both ends of the core. Along the axial direction of the core, the extension line of the positive tab 11 coincides with the negative tab 23. When a large external force (such as ≥13KN) is applied to the surface of the core, the core will undergo a large deformation. Since the positive tab 11 and negative tab 23 are located on the same straight line, when the core undergoes a large deformation, the positive tab 11 and negative tab 23 are likely to come into contact with their corresponding negative and positive plates, which may cause the core to catch fire or explode, posing a hidden danger to the mass application of the core.

[0050] As shown in Figure 2, the positive electrode tab 11 and the negative electrode tab 23 of the present invention are located at both ends of the core. Along the axial direction of the core, the extension line of the positive electrode tab 11 does not coincide with the negative electrode tab 23. Therefore, when a large external force (e.g., ≥13KN) is applied to the surface of the core, the positive electrode tab 11 and the negative electrode tab 23 are not on the same straight line, and the core is looser than the conventional structure. When the core undergoes large deformation, the positive electrode tab 11 and the negative electrode tab 23 are not likely to come into contact with their corresponding negative electrode 2 and positive electrode 1, thereby making it less likely for the core to catch fire or explode, thus improving the safety of the core in mass application.

[0051] The pouch-pack cylindrical battery mentioned in the embodiments of this application can be a single physical module comprising one or more cores to provide higher voltage and capacity. For example, the battery mentioned in this application can include cores, battery modules, or battery packs. A core is the smallest unit that makes up a battery and can independently perform the functions of charging and discharging. When there are multiple cores, the multiple cores are connected in series, parallel, or mixed through a busbar. In some embodiments, the battery can be a battery module; when there are multiple cores, the multiple cores are arranged and fixed to form a battery module. In some embodiments, the battery can be a battery pack, the battery pack including a battery housing and cores, with the cores or battery modules housed in the battery housing.

[0052] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0053] As shown in Figure 4, in one embodiment, the thickness of the negative electrode 2 is 18μm-28μm.

[0054] Specifically, the thickness of the negative electrode 2 is any one value or a range of any two values ​​from 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm or 28μm; in a preferred embodiment, the thickness of the negative electrode 2 is 18μm-24μm.

[0055] By controlling the thickness of the negative electrode 2 between 18μm and 28μm, this invention can effectively shorten the transmission distance of electrons and lithium ions inside the electrode, which helps to reduce the internal resistance of the battery and improve the rate performance of the battery.

[0056] As shown in Figure 4, in one embodiment, the bifacial areal density of the negative electrode 2 is 1.6-2.4 mg / cm³. 2 The compaction density of negative electrode 2 is 1.1-1.3 g / cm³. 3 .

[0057] Specifically, the areal density of the negative electrode 2 on both sides is 1.6 mg / cm³. 2 1.8 mg / cm 2 2.0 mg / cm2 2.2 mg / cm 2 Or 2.4 mg / cm 2 The value is any one point value or a range of any two point values; in a preferred embodiment, the bifacial areal density of the negative electrode 2 is 1.8 mg / cm³. 2 -2.2mg / cm 2 .

[0058] By optimizing the bifacial density of the negative electrode 2, the thickness of the negative electrode 2 can be controlled, improving the utilization rate of the negative electrode material, thereby increasing the battery capacity and energy density.

[0059] When the areal density of both sides of the negative electrode 2 is greater than 2.2 mg / cm³ 2 This means that more negative electrode active material is loaded on the same area, which theoretically may increase the battery capacity. However, excessively high areal density will increase the thickness of the negative electrode 2, leading to increased internal resistance and affecting the battery's charge and discharge efficiency, thus limiting the increase in battery capacity to some extent. When the bifacial areal density of the negative electrode 2 is less than 1.6 mg / cm³, the battery capacity will be increased. 2 When the amount of active material in the double-sided coating is reduced, the amount of active material in the coating means that the number of lithium ions that can be stored and released during charging and discharging is reduced, and the energy that can be stored per unit volume is also reduced, so the battery capacity will also decrease.

[0060] Specifically, the compaction density of negative electrode 2 is 1.1 g / cm³. 3 1.15g / cm 3 1.2g / cm 3 1.25g / cm 3 Or 1.3g / cm 3 The value is any one point or a range of any two point values. In a preferred embodiment, the compaction density of the negative electrode 2 is 1.15 g / cm³. 3 -1.25g / cm 3 .

[0061] By controlling the compaction density of the negative electrode 2, the porosity and void distribution of the negative electrode 2 can be controlled, thereby adjusting the ion conduction capability of the battery during charging and discharging, and thus changing the rate performance of the battery. When the compaction density of the negative electrode 2 is greater than 1.30 g / cm³... 3 Excessive compaction density can easily lead to excessive stress within the negative electrode 2, causing particle breakage within the silicon-based negative electrode material and affecting electrode performance; when the compaction density of the negative electrode 2 is less than 1.10 g / cm³, the negative electrode 2 will be negatively affected. 3If the compaction density is too low, it will lead to insufficient filling of active material in the negative electrode 2, thereby reducing the battery capacity. On the other hand, it may also lead to an increase in the voids inside the negative electrode 2, thereby increasing the internal resistance of the battery and affecting the rate performance of the battery.

[0062] As shown in Figure 2, in one embodiment, the projection of the positive electrode tab 11 along the axial direction of the core onto the second end face of the core and the projection of the negative electrode tab 12 along the axial direction of the core onto the second end face of the core are located on both sides of the central axis of the core, and the positive electrode tab 11 and the negative electrode tab 12 are arranged in parallel.

[0063] In this invention, the positive electrode tab 11 and the negative electrode tab 23 are disposed at both ends of the core, and the projection of the positive electrode tab 11 on the second end face of the core and the negative electrode tab 12 are located on both sides of the core's central axis and are arranged in parallel. Therefore, when a large external force (e.g., ≥13KN) is applied to the core surface, the core is relatively loose. Since the positive electrode tab 11 and the negative electrode tab 23 are not on the same side of the central axis, when the core undergoes large deformation, the positive electrode tab 11 and the negative electrode tab 23 are not likely to come into contact with their corresponding positive and negative electrodes, thereby making it less likely for the core to catch fire or explode, thus improving the safety of the core in mass application.

[0064] As shown in Figure 2, in one embodiment, the projection of the positive electrode tab 11 along the axial direction of the core onto the second end face of the core and the projection of the negative electrode tab 12 along the axial direction of the core onto the second end face of the core are symmetrically arranged about the central axis of the core.

[0065] The positive electrode tab 11 and negative electrode tab 23 of the present invention are disposed at both ends of the core, and the projection of the positive electrode tab 11 on the second end face of the core and the negative electrode tab 12 are symmetrically arranged about the central axis of the core. Therefore, when a large external force (e.g., ≥13KN) is applied to the surface of the core, the core is relatively loose. Since the positive electrode tab 11 and negative electrode tab 23 are located on both sides of the central axis, when the core undergoes large deformation, the positive electrode tab 11 and negative electrode tab 23 are not likely to come into contact with their corresponding positive and negative electrodes, thereby making it less likely for the core to catch fire or explode, thus improving the safety of the core in mass application.

[0066] Furthermore, since the positive tab 11 and the negative tab 23 are symmetrically arranged about the center of the core, the lead-out position of the negative tab 23 makes the force on the core more uniform in the tab width direction or in the compression direction at a 45-degree angle to the tab width direction. At the same time, it reduces the maximum external force on the tab locally in the tab width direction or in the compression direction at a 45-degree angle to the tab width direction, and reduces the rate of increase of the reaction force perpendicular to the tab width direction. This prevents the electrode from being subjected to excessive pressure or faster impact locally during the compression process, which could lead to electrode breakage and puncture of the diaphragm 3, resulting in short circuit failure within the core. Ultimately, this gives the core good compression resistance.

[0067] In other embodiments, the connecting line between the centers of the two end faces of the core is used as the central axis, and the positive electrode tab 11 and the negative electrode tab 23 are located on both sides of the central axis, thereby avoiding the positive electrode tab 11 and the negative electrode tab 23 from easily coming into contact with their corresponding negative and positive electrodes when the core undergoes large deformation, thus making it less likely for the core to catch fire or explode, and improving the safety of mass application of the core.

[0068] As shown in Figure 3, the projection of the positive electrode 1 onto the separator 3 is located inside the projection of the negative electrode 2 onto the separator 3.

[0069] In some embodiments, the positive electrode 1 includes a positive current collector and a positive electrode material layer coated on the surface of the positive current collector. The positive electrode material layer includes a positive electrode active material. There are no particular limitations on the positive electrode active material, and any positive electrode active material in the art can be used. For example, it may include at least one of lithium nickel cobalt manganese oxide (811, 622, 523, 111), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide, lithium manganese oxide, lithium manganese iron phosphate, or lithium titanate.

[0070] In some embodiments, the positive electrode material layer further includes a positive electrode conductive agent. The type of positive electrode conductive agent is not particularly limited, as long as it achieves the purpose of this application. Examples of positive electrode conductive agents may include, but are not limited to, at least one of conductive carbon black (SuperP), carbon nanotubes (CNTs), carbon nanofibers, flake graphite, acetylene black, carbon black, Ketjen black, carbon dots, or graphene; the above-mentioned positive electrode conductive agents may be used alone or in any combination.

[0071] In some embodiments, the positive electrode material layer further includes a positive electrode binder. There are no particular limitations on the type of positive electrode binder, as long as it is a material that can be dissolved or dispersed in the liquid medium used during electrode manufacturing. Examples of positive electrode adhesives may include, but are not limited to, one or more of the following: resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, and nitrocellulose; rubber-like polymers such as styrene-butadiene rubber, nitrile rubber, fluororubber, isoprene rubber, polybutadiene rubber, and ethylene-propylene rubber; thermoplastic elastomer-like polymers such as styrene-butadiene-styrene block copolymers or their hydrides, ethylene-propylene-diene terpolymers, styrene-ethylene-butadiene-ethylene copolymers, and styrene-isoprene-styrene block copolymers or their hydrides; soft resin-like polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymers, and propylene-α-olefin copolymers; fluorinated polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene-ethylene copolymers; and polymer compositions with ion conductivity of alkali metal ions (especially lithium ions). The above-mentioned positive electrode adhesive can be used alone or in any combination.

[0072] In some embodiments, the type of solvent used to form the positive electrode slurry is not limited, as long as it is a solvent capable of dissolving or dispersing the positive electrode material, conductive agent, positive electrode binder, and thickener used as needed. Examples of solvents used to form the positive electrode slurry may include any of aqueous solvents and organic solvents. Examples of aqueous media may include, but are not limited to, water and mixtures of alcohol and water. Examples of organic media may include, but are not limited to, aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N,N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide, and tetrahydrofuran; amides such as N-methylpyrrolidone, dimethylformamide, and dimethylacetamide; and aprotic polar solvents such as hexamethylphosphoramide and dimethyl sulfoxide.

[0073] In some embodiments, the positive electrode material layer further includes a thickener. Thickeners are typically used to adjust the viscosity of the slurry. In the case of using an aqueous medium, a thickener and styrene-butadiene rubber latex can be used for slurry preparation. There are no particular limitations on the type of thickener; examples may include, but are not limited to, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and their salts. The above-mentioned thickeners can be used alone or in any combination.

[0074] In some embodiments, the type of positive current collector is not particularly limited, and it can be any material known to be suitable for use as a positive current collector. Examples of positive current collectors may include, but are not limited to, aluminum.

[0075] In some embodiments, the negative electrode active material layer 22 further includes an additive.

[0076] In some embodiments, the additives include a negative electrode conductive agent, which may also be selected from any kind of conductive agent known to those skilled in the art. It may be one or more combinations of branched conductive agents, one-dimensional chain conductive agents, two-dimensional sheet conductive agents, polymer conductive agents, carbon black conductive agents and graphite conductive agents. More preferably, it may be selected from one or more of superconducting carbon black, acetylene black, Ketjen black, carbon nanotubes, carbon fibers, sheet graphite, graphene, polyacetylene, polythiophene, polypyrrole and polyaniline.

[0077] In some embodiments, the additive may further include a negative electrode binder. The negative electrode binder improves the bonding between negative electrode material particles and the bonding between the negative electrode material and the current collector. There are no particular limitations on the type of negative electrode binder, as long as it is a material stable to the electrolyte or the solvent used in electrode manufacturing. In some embodiments, the negative electrode binder includes a resin binder. Examples of resin binders include, but are not limited to, fluoropolymers, polyacrylonitrile (PAN), polyimide resins, acrylic resins, polyolefin resins, etc. When preparing the negative electrode slurry using an aqueous solvent, the negative electrode binder includes, but is not limited to, carboxymethyl cellulose (CMC) or its salts, styrene-butadiene rubber (SBR), polyacrylic acid (PAA) or its salts, polyvinyl alcohol, etc.

[0078] In some embodiments, the negative current collector 21 used as the negative electrode material can be any known current collector. Examples of the negative current collector 21 include, but are not limited to, copper.

[0079] In some embodiments, there are no particular limitations on the material and shape of the diaphragm 3, as long as it does not significantly impair the effectiveness of this application. The diaphragm 3 may be a resin, glass fiber, inorganic material, etc., formed from a material that is stable to the electrolyte of this application. In some embodiments, the diaphragm 3 includes a porous sheet or non-woven fabric-like material with excellent liquid retention properties. Examples of materials for the resin or glass fiber diaphragm 3 may include, but are not limited to, polyolefins, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, etc. In some embodiments, the polyolefin is polyethylene or polypropylene. In some embodiments, the polyolefin is polypropylene. The above-described materials for the diaphragm 3 may be used alone or in any combination.

[0080] As shown in Figures 5-7, in one embodiment, the positive electrode tab 11 is welded to the first end of the positive electrode sheet 1 in the width direction.

[0081] Specifically, along the length of the positive electrode 1, the positive electrode tab 11 is welded to the beginning, end, or any position in between of the positive electrode 1.

[0082] As shown in Figure 3, in one embodiment, the negative electrode tab 23 is welded to the end of the negative electrode sheet 2 that is away from the positive electrode tab 11 in the width direction.

[0083] Specifically, along the length of the negative electrode 2, the negative electrode tab 23 is welded to the beginning, end, or any position in between of the negative electrode 2.

[0084] As shown in Figure 3, in one embodiment, the area where the positive electrode tab 11 is welded to the positive electrode plate 1 is called the positive electrode tab welding area. The length of the positive electrode tab welding area is L1 mm, and the width of the positive electrode plate 1 is W mm. L1 and W satisfy the relationship: L1 < 1 / 2W.

[0085] As shown in Figure 3, in one embodiment, the area where the negative electrode tab 23 is welded to the negative electrode plate 2 is the negative electrode tab welding area. The length of the negative electrode tab welding area projected onto the positive electrode plate 1 is L2mm, and the width of the positive electrode plate 1 is W. L2 and W satisfy the relationship: L2 < 1 / 2W.

[0086] Specifically, when L1 < 1 / 2W and L2 < 1 / 2W, the projections of the welding ends of the positive electrode tab 11 and the negative electrode tab 23 along the length of the core do not coincide. When a large external force (e.g., ≥13KN) is applied to the surface of the core, the core will undergo a large deformation. The positive electrode tab 11 and the negative electrode tab 23 are not easy to contact with their corresponding negative electrode 2 and positive electrode 1, thus making it less likely for the core to catch fire or explode, thereby improving the safety of the core in mass application.

[0087] As shown in Figure 3, in one embodiment, L1, L2, and W satisfy the relationship: L1 + L2 < W - 2.

[0088] Specifically, when L1+L2<W-2, along the direction perpendicular to the length of the core, the projections of the welding ends of the positive electrode tab 11 and the negative electrode tab 23 in the direction of the core length do not coincide. When a large external force (such as ≥13KN) is applied to the surface of the core, the core will undergo a large deformation. The positive electrode tab 11 and the negative electrode tab 23 and their corresponding negative electrode plates 2 and positive electrode plates 1 are not easy to come into contact, thus making it less likely for the core to catch fire or explode, thereby improving the safety of the core in mass application.

[0089] Another aspect of the present invention provides an electrical device comprising a pouch-type cylindrical battery as described above.

[0090] In another embodiment, the electrical device includes the pouch-cell cylindrical battery provided in this application. The pouch-cell cylindrical battery can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0091] As an electrical device, the number of pouch cylindrical batteries can be selected according to its usage requirements.

[0092] This is an example of an electrical device. The device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the secondary battery for this device, a battery pack or battery module can be used.

[0093] Another example device could be an electronic cigarette, mobile phone, tablet, laptop, etc. These devices typically require a slim and lightweight design and can use a rechargeable battery as their power source.

[0094] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention is further described in detail below with reference to embodiments. However, it should be understood that the embodiments of this invention are merely for illustrative purposes and not for limiting the invention, and the embodiments are not limited to those given in the specification. Materials not specified in the embodiments were prepared under conventional conditions or according to the conditions recommended by the material supplier.

[0095] Furthermore, it should be understood that the one or more method steps mentioned in this invention do not preclude the existence of other method steps before or after the combination steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combination connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combination of devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0096] In the following embodiments, the reagents, materials and instruments used, unless otherwise specified, are commercially available or can be obtained through synthesis methods known in the art.

[0097] Example 1:

[0098] Cathode preparation:

[0099] 1.2% PVDF binder was thoroughly mixed in an appropriate amount of NMP to form a PVDF adhesive solution. Then, 2.8% conductive agent was added to the PVDF adhesive solution for dispersion, followed by 96% lithium cobalt oxide as the active material. Finally, the viscosity was adjusted to form a uniform positive electrode slurry. This slurry was then uniformly coated onto the positive electrode current collector aluminum foil, with a coating surface density of 13.2 mg / cm². 2 After drying in the coating machine oven, the material is rolled into a positive electrode strip with a compacted density of 3.77 g / cm³. 3 Then cut it into positive electrode sheets that are 734mm long and 28mm wide.

[0100] Anode preparation:

[0101] 0.8% CMC was added to deionized water and stirred, followed by the addition of sheet-like conductive carbon powder, then 2% polyacrylic binder, then 96% pure silicon, and finally 1.2% single-walled conductive carbon nanotubes for dispersion. The viscosity was then adjusted to form a uniform negative electrode slurry. This slurry was then uniformly coated onto an 8μm thick copper foil negative electrode current collector, with a coating surface density of 1.6 mg / cm³. 2 After drying in the coating machine oven, it is rolled into a negative electrode belt with a compacted density of 1.2 g / cm³. 3 Then it is cut into negative electrode sheets with a length of 780mm and a width of 29mm, and the thickness of the negative electrode sheets is 20μm.

[0102] Electrode welding:

[0103] Along the length of the positive electrode sheet, the positive electrode tab is welded to the head of the positive electrode sheet 1a region; the length of the positive electrode tab in the welding area of ​​the positive electrode sheet is L1, and the width of the positive electrode sheet 1 is W. L1 and W satisfy the relationship: L1 < 1 / 2W.

[0104] Along the length of the negative electrode sheet, the negative electrode tab is welded to the head of region 1b of the negative electrode sheet. The area where the negative electrode tab is welded to the negative electrode sheet is called the negative electrode tab welding area. The length of the negative electrode tab welding area projected onto the positive electrode sheet is L2, and the width of the positive electrode sheet is W. L2 and W satisfy the relationship: L2 < 1 / 2W;

[0105] Electrolyte preparation:

[0106] Lithium salt LiPF6 is dissolved in a solvent, which is a mixture of EC / PC / DEC / EMC solvent, with additives such as VC, FEC, and PS added. Strict control of ambient humidity is required during the fabrication process to prevent moisture introduction.

[0107] Fabrication of pouch-type cylindrical batteries:

[0108] The welded positive electrode sheet, separator, and welded negative electrode sheet are stacked in sequence, with the separator positioned between the positive and negative electrodes for isolation. Then, along the length of the electrode sheet, starting from the first end of the positive electrode sheet, it is wound into a bare cell. The bare cell is placed in a pouch cell, and then the tab adhesive and the pouch cell (aluminum-plastic film) are heat-sealed together. Electrolyte injection, high-temperature aging, formation, and sealing processes are then performed to produce a pouch cylindrical battery.

[0109] In the prepared battery cell, along the axial direction of the core, the projections of the positive electrode tab on the second end face of the core and the projections of the negative electrode tab on the second end face of the core are located on both sides of the core's central axis and are nearly symmetrical about the core's central axis (with a deviation of less than 0.5 mm).

[0110] Example 2

[0111] Example 2 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps in Example 1, but differs in that:

[0112] Electrode welding:

[0113] Along the length of the positive electrode sheet, the positive electrode tab is welded to the middle of region 2a of the positive electrode sheet;

[0114] Along the length of the negative electrode sheet, the negative electrode tab is welded to the middle of region 2b of the negative electrode sheet.

[0115] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core and the negative electrode tab are located on both sides of the central axis of the winding core and are arranged approximately symmetrically about the central axis of the winding core (with a deviation of less than 0.5 mm).

[0116] Example 3

[0117] Example 3 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps in Example 1, but differs in that:

[0118] Electrode welding:

[0119] Along the length of the positive electrode sheet, the positive electrode tab is welded to the tail end of region 3a of the positive electrode sheet;

[0120] Along the length of the negative electrode sheet, the negative electrode tab is welded to the tail end of region 3b of the negative electrode sheet.

[0121] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core and the negative electrode tab are located on both sides of the central axis of the winding core and are arranged approximately symmetrically about the central axis of the winding core (with a deviation of less than 0.5 mm).

[0122] Example 4

[0123] Example 4 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps in Example 1, but differs in that:

[0124] Electrode welding:

[0125] Along the length of the positive electrode sheet, the positive electrode tab is welded to the head of the positive electrode sheet region 1a;

[0126] Along the length of the negative electrode sheet, the negative electrode tab is welded to the head of the negative electrode sheet region 2b.

[0127] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core and the negative electrode tab are located on both sides of the central axis of the winding core and are arranged in parallel.

[0128] Example 5

[0129] Example 5 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps in Example 1, but differs in that:

[0130] Electrode welding:

[0131] Along the length of the positive electrode sheet, the positive electrode tab is welded to the head of the positive electrode sheet region 1a;

[0132] Along the length of the negative electrode sheet, the negative electrode tab is welded to the head of the negative electrode sheet region 2a.

[0133] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core is on the same side of the central axis as the negative electrode tab and does not intersect.

[0134] Comparative Example 1

[0135] Comparative Example 1 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps in Example 1, but differs in that:

[0136] Electrode welding:

[0137] Along the length of the positive electrode sheet, the positive electrode tab is welded to the head of the positive electrode sheet region 1a;

[0138] Along the length of the negative electrode sheet, the negative electrode tab is welded to the head of the negative electrode sheet 1a region.

[0139] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core is almost coincident with that of the negative electrode tab (the deviation is less than 0.5 mm).

[0140] Comparative Example 2

[0141] Comparative Example 2 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps in Example 1, but differs in that:

[0142] Electrode welding:

[0143] Along the length of the positive electrode sheet, the positive electrode tab is welded to the middle of region 2a of the positive electrode sheet;

[0144] Along the length of the negative electrode sheet, the negative electrode tab is welded to the middle of the negative electrode sheet region 2a.

[0145] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core is almost coincident with that of the negative electrode tab (the deviation is less than 0.5 mm).

[0146] Comparative Example 3

[0147] Comparative Example 3 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps of Example 1, but differs in that:

[0148] Electrode welding:

[0149] Along the length of the positive electrode sheet, the positive electrode tab is welded to the tail end of region 3a of the positive electrode sheet;

[0150] Along the length of the negative electrode sheet, the negative electrode tab is welded to the tail end of region 3a of the negative electrode sheet.

[0151] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core is almost coincident with that of the negative electrode tab (the deviation is less than 0.5 mm).

[0152] Comparative Example 4

[0153] Comparative Example 4 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps of Example 1, but differs in that:

[0154] The length of the positive electrode tab in the welding area of ​​the positive electrode plate is L1, and the width of the positive electrode plate 1 is W. L1 and W satisfy the relationship: L1 > 1 / 2W.

[0155] The area where the negative electrode tab is welded to the negative electrode sheet is called the negative electrode tab welding area. The length of the negative electrode tab welding area projected onto the positive electrode sheet is L2, and the width of the positive electrode sheet is W. L2 and W satisfy the relationship: L2 > 1 / 2W.

[0156] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core and the negative electrode tab are located on both sides of the central axis of the winding core and are symmetrically arranged about the central axis of the winding core.

[0157] Along the axis perpendicular to the core, the projection of the positive electrode tab onto the core in the axial direction partially overlaps with the projection of the negative electrode tab onto the core in the axial direction.

[0158] Comparative Example 5

[0159] Comparative Example 5 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps of Example 1, but differs in that:

[0160] Electrode welding:

[0161] Along the length of the positive electrode sheet, the positive electrode tab is welded to the head of the positive electrode sheet 1a region; the length of the positive electrode tab in the welding area of ​​the positive electrode sheet is L1, and the width of the positive electrode sheet 1 is W. L1 and W satisfy the relationship: L1 > 1 / 2W.

[0162] Along the length of the negative electrode sheet, the negative electrode tab is welded at the head of region 2b of the negative electrode sheet; the area where the negative electrode tab is welded to the negative electrode sheet is called the negative electrode tab welding area, the length of the negative electrode tab welding area projected onto the positive electrode sheet is L2, and the width of the positive electrode sheet is W. L2 and W satisfy the relationship: L2 > 1 / 2W.

[0163] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core and the negative electrode tab are located on both sides of the central axis of the winding core and are arranged in parallel.

[0164] Along the axis perpendicular to the core, the projection of the positive electrode tab onto the core in the axial direction partially overlaps with the projection of the negative electrode tab onto the core in the axial direction.

[0165] Comparative Example 6

[0166] Comparative Example 6 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps of Example 1, but differs in that:

[0167] Electrode welding:

[0168] Along the length of the positive electrode sheet, the positive electrode tab is welded to the head of the positive electrode sheet 1a region; the length of the positive electrode tab in the welding area of ​​the positive electrode sheet is L1, and the width of the positive electrode sheet 1 is W. L1 and W satisfy the relationship: L1 > 1 / 2W.

[0169] Along the length of the negative electrode sheet, the negative electrode tab is welded at the head of region 2a of the negative electrode sheet; the region where the negative electrode tab is welded to the negative electrode sheet is called the negative electrode tab welding area, the length of the negative electrode tab welding area projected onto the positive electrode sheet is L2, and the width of the positive electrode sheet is W. L2 and W satisfy the relationship: L2 > 1 / 2W.

[0170] In the prepared battery cell, along the axial direction of the winding core, the projection of the positive electrode tab on the second end face of the winding core does not intersect with the negative electrode tab;

[0171] Along the axis perpendicular to the core, the projection of the positive electrode tab onto the core in the axial direction partially overlaps with the projection of the negative electrode tab onto the core in the axial direction.

[0172] Comparative Example 7

[0173] Comparative Example 7 illustrates a pouch-pack cylindrical battery, a pouch-pack cylindrical battery, and an electrical device disclosed in this invention. It includes most of the operating steps of Example 1, but differs in that:

[0174] Electrode welding:

[0175] The length of the positive electrode tab in the welding area of ​​the positive electrode plate is L1, and the width of the positive electrode plate 1 is W. L1 and W satisfy the relationship: L1 = 1 / 2W;

[0176] The area where the negative electrode tab is welded to the negative electrode sheet is called the negative electrode tab welding area. The length of the negative electrode tab welding area projected onto the positive electrode sheet is L2, and the width of the positive electrode sheet is W. L2 and W satisfy the relationship: L2 = 1 / 2W.

[0177] In the prepared battery cell, along the axial direction of the core, the projection of the positive electrode tab on the second end face of the core and the negative electrode tab are located on both sides of the central axis of the core and are symmetrically arranged about the central axis of the core; along the axial direction perpendicular to the core, the projection of the positive electrode tab on the axial direction of the core and the projection of the negative electrode tab on the axial direction of the core abut against each other.

[0178] Performance testing:

[0179] Compression test:

[0180] Test method: 15 soft-pack lithium-ion batteries prepared in Examples 1-5 and Comparative Examples 1-7 were prepared and subjected to extrusion test on a 13KN press.

[0181] The test results are shown in Table 1:

[0182] Table 1. Extrusion test results of Examples 1-5 and Comparative Examples 1-6 of the present invention.

[0183] As can be seen from Table 1, the soft-pack cylindrical batteries prepared in Examples 1-5 of the present invention can still maintain the positive and negative electrodes without internal short circuits during the extrusion process under a pressure of 13KN, and pass the extrusion test 100%;

[0184] Comparative Examples 1-3 use the existing soft-pack cylindrical battery structure. Under the pressure of 13KN, the positive and negative electrodes will experience excessive local stress, causing the electrode sheets to break, which in turn damages the separator and causes an internal short circuit in the cell. In severe cases, the cell may catch fire and explode.

[0185] In the soft-pack cylindrical batteries prepared in Comparative Examples 4-7, although the projection of the positive electrode tab on the second end face of the core does not intersect with the negative electrode tab along the axial direction of the core, the projection of the positive electrode tab on the axial direction of the core and the projection of the negative electrode tab on the axial direction of the core abut against each other along the direction perpendicular to the axial direction of the core. Under a pressure of 13KN, they will also deform. This is because the lead-out of the negative electrode tab makes the force on the core more uniform in the tab width direction or in the direction of compression at an acute angle to the tab width direction. This reduces the maximum external force on the tab locally during the compression process, and also reduces the rate of increase of the reaction force perpendicular to the tab width direction. This prevents the electrode from being subjected to excessive pressure or faster impact locally during the compression process, which could lead to electrode breakage, puncture of the separator, and short circuit failure within the core. Ultimately, this gives the core good compression resistance.

[0186] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pouch cylindrical battery, characterized by: The soft package battery includes a soft package shell and a roll core arranged in the soft package shell, the roll core includes a positive electrode sheet, a separator and a negative electrode sheet; The negative electrode sheet includes a negative electrode current collector and negative electrode active material layers arranged on both sides of the negative electrode current collector, the thickness of the negative electrode active material layers is 12-20 μm; The negative electrode active material layer includes a negative electrode silicon-based active material, the negative electrode silicon-based active material includes pure silicon particles, the mass percentage of the pure silicon particles in the negative electrode silicon-based active material is 65-100%; The positive electrode sheet, the separator and the negative electrode sheet are laminated and wound to form the roll core, the positive electrode sheet and the negative electrode sheet are separated by the separator in the roll core; a positive electrode tab is arranged on the positive electrode sheet, the positive electrode tab is located at a first end of the roll core, a negative electrode tab is arranged on the negative electrode sheet, the negative electrode tab is located at a second end of the roll core, the projection of the positive electrode tab on the second end face of the roll core along the axial direction of the roll core does not intersect with the projection of the negative electrode tab on the second end face of the roll core along the axial direction of the roll core.

2. The pouch cylinder battery of claim 1, wherein: The thickness of the negative electrode sheet is 18-28 μm.

3. The pouch cylinder battery of claim 1, wherein: The double-sided area density of the negative electrode sheet is 1.6-2.4 mg / cm 2 ; the compaction density of the negative electrode sheet is 1.1-1.3 g / cm 3 .

4. The pouch cylindrical battery according to any one of claims 1 to 3, characterized by: The projection of the positive electrode tab on the second end face of the roll core along the axial direction of the roll core and the projection of the negative electrode tab on the second end face of the roll core along the axial direction of the roll core are respectively located on both sides of the central axis of the roll core, and the positive electrode tab and the negative electrode tab are arranged in parallel.

5. The pouch cylinder battery of claim 4, wherein: The projection of the positive electrode tab on the second end face of the roll core along the axial direction of the roll core and the projection of the negative electrode tab on the second end face of the roll core along the axial direction of the roll core are symmetrically arranged about the central axis of the roll core.

6. The pouch cylinder battery of claim 1, wherein: The projection of the positive electrode sheet on the separator is located inside the projection of the negative electrode sheet on the separator.

7. The pouch cylinder battery of claim 1, wherein: The positive electrode tab is welded at one end in the width direction of the positive electrode sheet.

8. The pouch cylinder battery of claim 7, wherein: The negative electrode tab is welded at one end away from the positive electrode tab in the width direction of the negative electrode sheet.

9. The pouch cylinder battery of claim 8, wherein: The area of the positive electrode tab welded to the positive electrode sheet is a positive electrode tab welding area, the length of the positive electrode tab welding area is L1 mm, the width of the positive electrode sheet is W mm, and the L1 and W satisfy the relationship L1 < 1 / 2 W.

10. The pouch cylinder battery of claim 9, wherein: The area of the negative electrode tab welded to the negative electrode sheet is a negative electrode tab welding area, the length of the negative electrode tab welding area projected on the positive electrode sheet is L2 mm, and the L2 and W satisfy the relationship L2 < 1 / 2 W.

11. The pouch cylinder battery of claim 10, wherein: The L1, L2 and W satisfy the relationship L1 + L2 < W - 2.

12. An electrical device, characterized by: The electric device includes the soft package cylindrical battery according to any one of claims 1-11.

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