A positive electrode slurry, a negative electrode slurry, a positive electrode tab without a current collector, a negative electrode tab without a current collector, and a battery

Abstract

The application provides a positive electrode paste containing metal wires, a negative electrode paste, a positive electrode sheet without a current collector, a negative electrode sheet and a battery. The application increases the toughness of the active material layer by adding a small amount of metal wires into the positive / negative electrode paste, and improves the problem of insufficient electronic conductivity caused by the absence of the current collector; the application coats the positive / negative electrode paste containing metal wires on a diaphragm, further increases the manufacturability of the active material layer, and enables the industrial production and manufacturing of the current collector-free battery; the added metal wires account for 0.02-2% of the total solid content, and the energy density of the overall battery is higher than that of a conventional battery; due to the addition of the metal wires, the membrane sheet resistivity of the positive electrode sheet is reduced from 5-100 ohm*cm to 0.01-3 ohm*cm, the potential difference of the sheet in the thickness direction is smaller in the charging and discharging process of the battery, the thickness of the active material layer can be increased under the same performance, and the battery energy density is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a positive electrode slurry containing metal wires, a negative electrode slurry, a positive electrode sheet without current collectors, a positive electrode sheet and a battery. BACKGROUND

[0002] In recent years, with the development of economy and the progress of society, lithium ion batteries and sodium ion batteries are more and more widely used. Especially in the field of mobile devices, the pursuit of energy density, the current commercial chemical battery is getting closer to the limit of energy density, and the new high specific energy battery is still far from commercial application, which requires improving the energy density of lithium ion batteries and sodium ion batteries from the structure of the battery. Increasing the thickness of the electrode sheet and using a self-supporting electrode sheet without current collectors are the most common methods to improve the energy density of the battery.

[0003] However, increasing the thickness of the electrode sheet will make the electron and ion transmission path longer, and the traditional self-supporting electrode sheet without current collectors will exacerbate the ohmic polarization, and the self-supporting electrode sheet without current collectors is usually brittle and lacks toughness, which has great difficulty in industrialized manufacturing.

[0004] Based on the defects of the current battery without current collectors, it is necessary to improve it. SUMMARY

[0005] The present application provides a positive electrode slurry containing metal wires, a negative electrode slurry, a positive electrode sheet without current collectors, a negative electrode sheet and a battery to solve or at least partially solve the defects in the prior art.

[0006] In a first aspect, the present application provides a positive electrode slurry containing metal wires, comprising a positive electrode slurry and metal wires.

[0007] Preferably, the metal wire comprises at least one of copper wire, aluminum wire, nickel wire, silver wire and gold wire;

[0008] And / or, the diameter of the metal wire is 0.1-200μm, preferably the diameter of the metal wire is 2-20μm;

[0009] And / or, the aspect ratio of the metal wire is 20-5000, preferably the aspect ratio of the metal wire is 200-1000.

[0010] Preferably, the positive electrode slurry comprises positive electrode active material, conductive agent, positive electrode binder and positive electrode solvent, and the mass of the metal wire is 0.02-2% of the total solid mass in the positive electrode slurry containing metal wires;

[0011] Preferably, the mass of the metal wire is 0.1-0.5% of the total solid mass in the positive electrode slurry.

[0012] Preferably, the positive active material comprises at least one of lithium cobaltate, lithium iron phosphate, lithium manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, sodium nickel cobalt manganate, composite sodium iron pyrophosphate phosphate, sodium ferrous sulfate, sodium vanadium phosphate;

[0013] And / or, the conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, graphene and nanometer carbon fiber;

[0014] And / or, the positive electrode binder comprises at least one of PVDF, PTFE, CMC, SBR, PAN, PAA;

[0015] And / or, the positive electrode solvent comprises at least one of NMP, water;

[0016] And / or, the mass ratio of positive active material, conductive agent, positive electrode binder, positive electrode solvent and metal wire in the positive electrode slurry containing metal wire is (90-98.6):(0.01-5):(0.1-5):(40-100):(0.02-2).

[0017] In a second aspect, the present application also provides a negative electrode slurry containing metal wire, characterized in that it comprises a negative electrode slurry and a metal wire.

[0018] Preferably, the metal wire comprises at least one of copper wire, aluminum wire, nickel wire, silver wire, gold wire;

[0019] And / or, the diameter of the metal wire is 0.1-200μm, preferably, the diameter of the metal wire is 2-20μm;

[0020] And / or, the aspect ratio of the metal wire is 20-5000, preferably, the aspect ratio of the metal wire is 200-1000.

[0021] Preferably, the negative electrode slurry comprises negative active material, conductive agent, thickening agent, negative electrode binder and negative electrode solvent, and the mass of the metal wire is 0.02-2% of the total solid material in the negative electrode slurry containing metal wire;

[0022] Preferably, the mass of the metal wire is 0.1-0.5% of the total solid material in the negative electrode slurry.

[0023] Preferably, the negative active material comprises at least one of graphite, soft carbon, hard carbon, silicon-based compounds, titanium-based compounds, phosphorus-based compounds;

[0024] And / or, the conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, graphene and nanometer carbon fiber;

[0025] and / or, the thickening agent comprises CMC;

[0026] and / or, the negative electrode binder comprises one of SBR, PVDF, PAN, PI, PAA;

[0027] and / or, the negative electrode solvent comprises at least one of water, NMP;

[0028] and / or, the mass ratio of the negative electrode active material, the conductive agent, the thickening agent, the negative electrode binder, the negative electrode solvent, and the metal wire in the negative electrode slurry containing metal wire is (90-98.6):(0.01-5):(0.2-3):(0.2-5):(40-130):(0.02-2).

[0029] In a third aspect, the present application further provides a positive electrode tab without current collector, comprising:

[0030] a separator, a surface of the separator being provided with a positive electrode active material layer, wherein the positive electrode active material layer is obtained by drying the positive electrode slurry containing metal wire coated on the surface of the separator;

[0031] a positive electrode tab located at one side of the positive electrode active material layer.

[0032] In a fourth aspect, the present application further provides a negative electrode tab without current collector, comprising:

[0033] a separator, a surface of the separator being provided with a negative electrode active material layer, wherein the negative electrode active material layer is obtained by drying the negative electrode slurry containing metal wire coated on the surface of the separator;

[0034] a negative electrode tab located at one side of the negative electrode active material layer.

[0035] Preferably, the separator comprises at least one of PE separator, PP separator, PP / PE separator, PP / PE / PP separator, PE separator containing heat-resistant coating, PP separator containing heat-resistant coating, PI separator, PA separator, cellulose separator;

[0036] the thickness of the heat-resistant coating is 1-3 μm, and the heat-resistant coating comprises but is not limited to aluminum trioxide coating, boehmite coating;

[0037] the thickness of the separator is 3-20 μm;

[0038] the positive electrode tab comprises at least one of aluminum foil, aluminum sheet, foamed aluminum, and aluminum wire;

[0039] the negative electrode tab comprises at least one of nickel foil, nickel sheet, nickel wire, foamed nickel, copper foil, copper sheet, copper wire, foamed copper, aluminum foil, aluminum sheet, foamed aluminum, and aluminum wire.

[0040] In a fifth aspect, the present application further provides a current collector-free battery, comprising at least one of the current collector-free positive electrode sheet and at least one of the current collector-free negative electrode sheet.

[0041] The current collector-free positive electrode sheet and the current collector-free negative electrode sheet are arranged in an interleaved manner.

[0042] The positive electrode slurry containing metal wires, the negative electrode slurry, the current collector-free positive electrode sheet, the negative electrode sheet and the battery of the present application have the following advantages over the prior art:

[0043] 1. The positive electrode slurry / negative electrode slurry containing metal wires of the present application increases the toughness of the active material layer by adding a small amount of metal wires in the positive electrode slurry / negative electrode slurry, and improves the problem of insufficient electronic conductivity caused by the absence of a current collector; the present application further increases the manufacturability of the active material layer by coating the positive electrode slurry / negative electrode slurry containing metal wires on the separator, so that the current collector-free battery can be produced and manufactured industrially.

[0044] 2. Compared with the traditional current collector-free self-supporting electrode sheet, the current collector-free positive electrode sheet / negative electrode sheet of the present application uses a positive electrode slurry / negative electrode slurry coated on the separator to form a positive / negative separator integrated component, which reduces the components in the winding or stacking process and is more conducive to the control of "Overhang"; at the same time, the positive / negative separator integrated component makes the contact between the separator and the active material more close and less likely to be separated, thereby improving the cycle performance of the battery; the metal wires added in the present application are usually only 0.02-2% of the total solid content, and the metal current collector foil is cancelled; under the same performance, the energy density of the overall battery is higher than that of the battery manufactured by the traditional electrode sheet; and since the active material is attached to the flexible separator, the electrode sheet has good flexibility and can form a continuous winding, which is convenient for batch and continuous production; the thickness of the positive current collector (usually aluminum foil) of the traditional electrode sheet is usually 8-15 μm, and the thickness of the negative current collector is 4.5-10 μm, and the volume of the current collector accounts for 2-10% of the total volume of the electrode sheet; while the metal wires added in the current collector-free positive electrode sheet / negative electrode sheet of the present application are usually only 0.02-2% of the total solid content, and the energy density of the overall battery is higher than that of the battery manufactured by the traditional electrode sheet; due to the addition of metal wires, the resistivity of the positive electrode sheet is reduced from 5-100 Ω·cm to 0.01-3 Ω·cm, and in the charging and discharging process of the battery, the potential difference of the electrode sheet in the thickness direction is smaller, and under the same performance, the thickness of the active material layer can be increased, which is conducive to further improving the energy density of the battery; by directly attaching the positive electrode slurry / negative electrode slurry containing metal wires to the separator, the positive / negative active material and the separator are combined more closely, the internal resistance of the battery is reduced, and the cycle life of the battery is improved. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0046] Figure 1 Structure diagram of the positive electrode plate without current collector of the present application;

[0047] Figure 2 Structure diagram of the negative electrode plate without current collector of the present application;

[0048] Figure 3 Structure diagram of the positive electrode plate without current collector and the negative electrode plate without current collector of the present application being staggered and stacked. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of the present application.

[0050] It should be noted that similar reference numerals and letters indicate similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0051] The following will be described in detail respectively. It should be noted that the sequence of the following embodiments is not limited as the preferred sequence of the embodiments. In addition, in the description of the present application, the term "comprising" means "including but not limited to". Various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is only for the convenience and brevity, and should not be understood as the hard limitation of the scope of the present application; therefore, it should be considered that the described range has been specifically disclosed all possible sub-ranges and single values in the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed the sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the single numbers in the range, such as 1, 2, 3, 4, 5 and 6, which are applicable regardless of the range. In addition, whenever a numerical range is indicated in this text, it means that any cited number (fraction or integer) in the indicated range is included.

[0052] The application provides a positive electrode slurry containing metal wires, comprising the positive electrode slurry and the metal wires.

[0053] In some embodiments, the metal wires in the positive electrode slurry containing metal wires comprise at least one of copper metal wires, aluminum metal wires, nickel metal wires, silver metal wires, and gold metal wires, preferably, the metal wires are aluminum metal wires.

[0054] In some embodiments, the diameter of the metal wires is 0.1-200 μm, preferably, the diameter of the metal wires is 2-20 μm.

[0055] In some embodiments, the aspect ratio of the metal wires is 20-5000, preferably, the aspect ratio of the metal wires is 200-1000, and specifically, the aspect ratio represents the ratio of the length to the diameter of the metal wires.

[0056] In some embodiments, the positive electrode slurry comprises a positive electrode active material, a conductive agent, a positive electrode binder, and a positive electrode solvent, and the mass of the metal wires is 0.02-2% of the total solid material in the positive electrode slurry containing metal wires; preferably, the mass of the metal wires is 0.1-0.5% of the total solid material in the positive electrode slurry. Specifically, the total solid material in the positive electrode slurry containing metal wires comprises materials other than the positive electrode solvent, i.e., the total solid material in the positive electrode slurry containing metal wires comprises the positive electrode active material, the conductive agent, the positive electrode binder, and the metal wires, wherein the mass of the metal wires is 0.02-2% of the total solid material.

[0057] In some embodiments, the material used for the positive electrode active material is not limited, and a common positive electrode active material for lithium ion batteries can be used, for example, the positive electrode active material comprises at least one of lithium cobaltate, lithium iron phosphate, lithium manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, sodium nickel cobalt manganate, composite sodium iron pyrophosphate phosphate, sodium ferrous sulfate, sodium vanadium phosphate, etc., but is not limited thereto.

[0058] In some embodiments, the material used for the conductive agent is not limited, and a common conductive agent for lithium ion batteries can be used, for example, the conductive agent comprises at least one of conductive carbon black, conductive graphite, carbon nanotubes, and nanometer carbon fibers, but is not limited thereto.

[0059] In some embodiments, the material used for the positive electrode binder is not limited, and a common positive electrode binder for lithium ion batteries can be used, for example, the positive electrode binder comprises at least one of PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), CMC (sodium carboxymethyl cellulose), SBR (styrene butadiene rubber emulsion), PAN (polyacrylonitrile), PAA (polyacrylic acid), etc., but is not limited thereto.

[0060] In some embodiments, the positive electrode solvent is not particularly limited, and a positive electrode solvent commonly used in lithium ion batteries can be used, for example, the positive electrode solvent includes, but is not limited to, at least one of NMP (N-methyl pyrrolidone), water, and the like.

[0061] In some embodiments, the mass ratio of the positive electrode active material, the conductive agent, the positive electrode binder, and the positive electrode solvent in the positive electrode slurry containing the metal wire is determined according to actual conditions, for example, the mass ratio of the positive electrode active material, the conductive agent, the positive electrode binder, and the positive electrode solvent is (90-98.6):(0.01-5):(0.1-5):(40-100); the mass of the metal wire is 0.02-2% of the sum of the mass of the positive electrode active material, the conductive agent, the binder, and the metal wire, preferably 0.1-0.5%.

[0062] In some embodiments, the mass ratio of the positive electrode active material, the conductive agent, the positive electrode binder, the positive electrode solvent, and the metal wire in the positive electrode slurry containing the metal wire is (90-98.6):(0.01-5):(0.1-5):(40-100):(0.02-2).

[0063] The preparation method of the positive electrode slurry containing the metal wire is as follows: the positive electrode active material, the conductive agent, the binder, and the positive electrode solvent in the positive electrode slurry are added to a stirrer for stirring and dispersion, and then the metal wire is added, and the stirring and dispersion are continued, to obtain the positive electrode slurry containing the metal wire.

[0064] Based on the same inventive concept, the application further provides a negative electrode slurry containing a metal wire, which includes the negative electrode slurry and the metal wire.

[0065] In some embodiments, the metal wire in the negative electrode slurry containing the metal wire includes at least one of a copper metal wire, an aluminum metal wire, a nickel metal wire, a silver metal wire, and a gold metal wire.

[0066] In some embodiments, the diameter of the metal wire is 0.1-200 μm, and preferably, the diameter of the metal wire is 2-20 μm.

[0067] In some embodiments, the aspect ratio of the metal wire is 20-5000, and preferably, the aspect ratio of the metal wire is 200-1000.

[0068] In some embodiments, the negative electrode slurry comprises a negative electrode active material, a conductive agent, a thickening agent, a negative electrode binder, and a negative electrode solvent, the mass of the metal wire is 0.02-2% of the total mass of solid substances in the negative electrode slurry containing the metal wire; preferably, the mass of the metal wire is 0.1-0.5% of the total mass of solid substances in the negative electrode slurry. Specifically, the total mass of solid substances in the negative electrode slurry containing the metal wire includes substances other than the negative electrode solvent, i.e., the total mass of solid substances in the negative electrode slurry containing the metal wire includes the negative electrode active material, the conductive agent, the thickening agent, the negative electrode binder, and the metal wire, wherein the mass of the metal wire is 0.02-2% of the total mass of solid substances.

[0069] In some embodiments, the negative electrode active material is not particularly limited in material, and a commonly used negative electrode active material for lithium ion batteries can be used, for example, the negative electrode active material includes at least one of graphite, soft carbon, hard carbon, silicon-based compounds, titanium-based compounds, phosphorus-based compounds, etc.

[0070] In some embodiments, the conductive agent is not particularly limited in material, and a commonly used conductive agent for lithium ion batteries can be used, for example, the conductive agent includes but is not limited to at least one of conductive carbon black (Super-P), conductive graphite, carbon nanotubes, and nanometer carbon fibers, etc.

[0071] In some embodiments, the thickening agent in the negative electrode slurry is not particularly limited in material, and a commonly used thickening agent for lithium ion batteries can be used, for example, the thickening agent can be CMC, etc.

[0072] In some embodiments, the negative electrode solvent is not particularly limited in material, and a commonly used negative electrode solvent for lithium ion batteries can be used, for example, the negative electrode solvent includes but is not limited to at least one of NMP, water, etc.

[0073] In some embodiments, the negative electrode binder is not particularly limited in material, and a commonly used negative electrode binder for lithium ion batteries can be used, for example, the negative electrode binder includes but is not limited to at least one of SBR, PVDF, PAN, PI (polyimide), PAA, etc.

[0074] In some embodiments, the mass ratio of the negative electrode active material, the conductive agent, the thickening agent, the negative electrode binder, and the negative electrode solvent in the negative electrode slurry containing the metal wire is determined according to actual conditions, for example, the mass ratio of the negative electrode active material, the conductive agent, the thickening agent, the negative electrode binder, and the negative electrode solvent is (90-98.6):(0.01-5):(0.2-3):(0.2-5):(40-130), and the mass of the metal wire is 0.02-2% of the sum of the masses of the negative electrode active material, the conductive agent, the thickening agent, the negative electrode binder, and the metal wire, preferably 0.1-0.5%.

[0075] In some embodiments, the mass ratio of the negative active material, the conductive agent, the thickening agent, the negative electrode binder, the negative electrode solvent, and the metal wire in the negative electrode slurry containing the metal wire is (90-98.6):(0.01-5):(0.2-3):(0.2-5):(40-130):(0.02-2).

[0076] The preparation method of the negative electrode slurry containing the metal wire is as follows: the negative active material, the conductive agent, the thickening agent, and the negative electrode solvent in the negative electrode slurry are added into a blender for stirring and dispersion, and then the metal wire is added, and the stirring and dispersion are continued, so that the negative electrode slurry containing the metal wire is obtained.

[0077] The positive electrode slurry / negative electrode slurry containing the metal wire of the present application increases the toughness of the active material layer by adding a small amount of metal wire into the positive electrode slurry / negative electrode slurry, and improves the problem of insufficient electronic conductivity caused by the absence of the current collector.

[0078] Based on the same inventive concept, the present application further provides a current collector-free positive electrode tab, comprising:

[0079] a separator, the surface of which is provided with a positive active material layer, wherein the positive active material layer is obtained by coating the positive electrode slurry containing the metal wire on the surface of the separator and drying;

[0080] a positive electrode tab located at one side of the positive active material layer.

[0081] Specifically, the preparation method of the current collector-free positive electrode tab is as follows: the positive electrode slurry containing the metal wire is coated on the surface of the separator, and the positive electrode tab is placed at the edge of the slurry, and then the positive electrode slurry is dried in a drying box to volatilize the positive electrode solvent, so that the positive active material layer is obtained.

[0082] In some embodiments, the positive electrode slurry is coated on the surface of the separator, and the area density is 0.5-2.5 g / 100 cm 2 . 2 The positive electrode slurry contains 0.5-2.5 g of the positive electrode slurry (calculated by the weight after drying) on the surface of the separator, that is, after the positive electrode slurry is coated on the surface of the separator and the positive electrode tab is placed at the edge of the slurry, the positive electrode slurry is dried in a drying box to volatilize the positive electrode solvent, and the area density of the positive electrode slurry is 0.5-2.5 g / 100 cm 2 .

[0083] Based on the same inventive concept, the present application further provides a current collector-free negative electrode tab, comprising:

[0084] a separator, the surface of which is provided with a negative active material layer, wherein the negative active material layer is obtained by coating the negative electrode slurry containing the metal wire on the surface of the separator and drying;

[0085] a negative electrode tab located at one side of the negative active material layer.

[0086] Specifically, the preparation method of the above-mentioned negative electrode sheet without current collector is as follows: after coating the negative electrode slurry containing metal wires onto the surface of the separator, negative electrode tabs are placed at the edge of the slurry, and then the sheet is placed in a drying oven to dry and allow the positive electrode solvent to evaporate, thereby obtaining the positive electrode active material layer.

[0087] In some embodiments, the negative electrode slurry is coated on the surface of the separator, and the areal density is 0.2–1.5 g / 100 cm³. 2 100cm 2 The separator contains 0.2–1.5 g of negative electrode slurry (based on the weight after drying). This involves coating the separator surface with a negative electrode slurry containing metal wires, placing negative electrode tabs at the edges of the slurry, and then drying it in a drying oven to allow the positive electrode solvent to evaporate. The resulting negative electrode slurry has an areal density of 0.2–1.5 g / 100 cm³. 2 .

[0088] In some embodiments, the specific material used for the separator is not limited, and a separator commonly used in lithium-ion batteries or sodium-ion batteries can be used. For example, the separator includes at least one of the following: PE separator (i.e., polyethylene separator), PP separator (i.e., polypropylene separator), PP / PE separator (i.e., polypropylene / polyethylene double-layer separator), PP / PE / PP separator (i.e., polypropylene / polyethylene / polypropylene triple-layer separator), PE separator with heat-resistant coating, PP separator with heat-resistant coating, PI separator, PA separator, cellulose separator, etc.

[0089] In some embodiments, the thickness of the diaphragm is 3–20 μm.

[0090] In some embodiments, the thickness of the heat-resistant coating is 1 to 3 μm, and the heat-resistant coating includes, but is not limited to, at least one of aluminum oxide coating, boehmite coating, etc.

[0091] In some embodiments, the positive electrode tab includes at least one of aluminum foil, aluminum sheet, aluminum foam, and aluminum wire;

[0092] In some embodiments, the negative electrode tab includes at least one of nickel foil, nickel sheet, nickel wire, nickel foam, copper foil, copper sheet, copper wire, copper foam, aluminum foil, aluminum sheet, aluminum foam, and aluminum wire.

[0093] In some embodiments, such as Figure 1 As shown, it is a schematic diagram of the structure of the current collector-free positive electrode of the present invention. Figure 1 These are top and side views of a positive electrode without a current collector. The positive electrode without a current collector includes a separator 1, a positive active material layer 2, and a positive electrode tab 3.

[0094] In some embodiments, such as Figure 2As shown, it is a structural schematic diagram of the jelly-roll-free negative electrode tab of the application, Figure 2 As shown, it is a structural schematic diagram of the jelly-roll-free negative electrode tab of the application,

[0095] The application further increases the manufacturability of the active material layer by coating the positive electrode slurry / negative electrode slurry containing metal wires on the separator, so that the jelly-roll-free battery can be industrialized.

[0096] Compared with the traditional jelly-roll-free self-supporting tab, the positive electrode slurry / negative electrode slurry of the application is coated on the positive-negative separator integrated component, which reduces the components of the winding or stacking process and is more conducive to the control of "Overhang"; at the same time, the positive-negative separator integrated component makes the contact between the separator and the active material more close and not easy to separate, which improves the cycle performance of the battery; the metal wire added in the application is usually only 0.02-2% of the total solid content, and the metal current collector foil is cancelled, so that the energy density of the overall battery is higher than that of the battery manufactured by the traditional tab under the same performance.

[0097] The active material is attached to the flexible separator, the tab has good flexibility, and continuous winding can be formed, which is convenient for batch and continuous production; the thickness of the positive current collector (usually aluminum foil) of the traditional tab is usually 8-15 μm, and the thickness of the negative current collector is 4.5-10 μm, and the volume of the current collector accounts for 2-10% of the total tab volume; while the metal wire added in the jelly-roll-free positive electrode tab / negative electrode tab of the application is usually only 0.02-2% of the total solid content, and the energy density of the overall battery is higher than that of the battery manufactured by the traditional tab; due to the addition of the metal wire, the film resistivity of the positive electrode tab is reduced from 5-100 Ω·cm to 0.01-3 Ω·cm, and the potential difference in the thickness direction of the tab is smaller during the charging and discharging process of the battery, so that the thickness of the active material layer can be increased under the same performance, which is conducive to further improving the energy density of the battery; the positive electrode / negative electrode active material and the separator are combined more closely by directly attaching the positive electrode slurry / negative electrode slurry containing metal wires to the separator, the internal resistance of the battery is reduced, and the cycle life of the battery is improved.

[0098] Based on the same inventive concept, the application also provides a jelly-roll-free battery comprising at least one jelly-roll-free positive electrode tab and at least one jelly-roll-free negative electrode tab,

[0099] The positive electrode tab without current collector and the negative electrode tab without current collector are arranged in an interlaced manner.

[0100] Specifically, referring to Figure 3 As shown in the figure, the positive electrode tab without current collector and the negative electrode tab without current collector are arranged in an interlaced manner. If the positive electrode tab without current collector is denoted as A and the negative electrode tab without current collector is denoted as B, the positive electrode tab without current collector and the negative electrode tab without current collector are arranged in an ABABABAB manner.

[0101] In some embodiments, the battery without current collector further comprises an electrolyte. Specifically, the electrolyte is a conventional lithium battery electrolyte. For example, the electrolyte comprises, by mass percentage, 10-15% of electrolyte salt, 0-15% of additive, and 75-90% of organic solvent. The organic solvent is mainly used as a carrier for lithium ions. Commonly used organic solvents include carbonate solvents such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC). The electrolyte salt, i.e., lithium salt, is used as a provider of lithium ions. Commonly used lithium salts include lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), and lithium bisfluorosulfonylimide (LiFSI). The additive is a substance with specific functions, such as a film-forming additive, a high / low temperature additive, an overcharge protection additive, a flame retardant additive, and a rate additive. Commonly used additives include vinylene carbonate (VC), fluoroethylene carbonate (FEC), PS, and DTD.

[0102] In some embodiments, the battery without current collector of the present application comprises a bare cell composed of the positive electrode tab without current collector and the negative electrode tab without current collector arranged in an interlaced manner. After the bare cell is placed in a shell and subjected to drying, electrolyte injection, formation, and capacity grading, a battery without current collector is obtained.

[0103] Specifically, in some embodiments, the positive electrode tab without current collector and the negative electrode tab without current collector are arranged in an interlaced manner in a one positive one negative manner. All positive electrode tabs are welded together, all negative electrode tabs are welded together, and the positive and negative electrode tabs are respectively welded to external tabs to obtain a bare cell.

[0104] The positive electrode slurry, the negative electrode slurry, the positive electrode tab without current collector, the positive electrode tab, and the battery of the present application are further described in the following specific embodiments. This part further describes the content of the present application in combination with specific embodiments, but should not be understood as a limitation of the present application. Unless otherwise specified, the technical means used in the embodiments are conventional means known to those skilled in the art. Unless otherwise specified, the reagents, methods, and devices used in the present application are conventional reagents, methods, and devices in the art.

[0105] Embodiment 1

[0106] The embodiment of the present application provides a positive electrode paste containing metal wires, which comprises a positive electrode active material, a conductive agent, a positive electrode binder, a positive electrode solvent and metal wires;

[0107] The positive electrode active material is lithium cobaltate; the conductive agent is a carbon nanotube; the positive electrode binder is PVDF; the positive electrode solvent is NMP; the metal wire is an aluminum metal wire, the diameter of the metal wire is 5 mu m, and the aspect ratio of the metal wire is 500.

[0108] The mass ratio of the positive electrode active material, the conductive agent, the positive electrode binder, the positive electrode solvent and the metal wire is 98.2:0.6:1.0:60:0.2.

[0109] The preparation method of the positive electrode paste containing metal wires comprises the following steps:

[0110] The positive electrode active material, the conductive agent and the positive electrode binder are added into the positive electrode solvent and mixed in a planetary mixer, and then the metal wire is added and uniformly stirred to obtain the positive electrode paste containing metal wires.

[0111] The embodiment of the present application further provides a positive electrode tab without a current collector, and a preparation method thereof comprises the following steps:

[0112] The positive electrode paste containing metal wires prepared in the embodiment 1 is coated on the surface of a separator, and the area density is controlled to be 1.74 g / 100 cm 2 An aluminum foil with a thickness of 10 mu m is placed at the edge of the positive electrode paste as a positive electrode tab, the aluminum foil and the positive electrode paste overlap by 2 mm (that is Figure 1 The separator overlaps by 2 m in the length direction (that is, the left-right direction), and is dried in a drying box to form a positive electrode active material layer, and the area density of the positive electrode paste after drying is 1.74 g / 100 cm 2 A positive electrode tab without a current collector is obtained.

[0113] The separator is a PE separator containing an aluminum trioxide coating (that is, the PE separator is coated with an aluminum trioxide coating, purchased from Yunnan Enxin New Material Co., Ltd., and the positive electrode paste is coated on the surface of the aluminum trioxide coating), the thickness of the PE separator is 5 mu m, and the thickness of the aluminum trioxide coating is 2 mu m.

[0114] Embodiment 2

[0115] The embodiment of the present application provides a negative electrode paste containing metal wires, which comprises a negative electrode active material, a conductive agent, a thickening agent, a negative electrode binder, a negative electrode solvent and metal wires;

[0116] The negative active material is artificial graphite; the conductive agent is conductive carbon black; the thickening agent is CMC; the negative electrode binder is SBR; the negative electrode solvent is water; the metal wire is a copper metal wire, the diameter of the metal wire is 3 mu m, and the length-diameter ratio is 1000;

[0117] The mass ratio of the negative active material, the conductive agent, the thickening agent, the negative electrode binder, the negative electrode solvent, and the metal wire is 97.2:0.3:1.1:1.3:75:0.1.

[0118] The preparation method of the above-mentioned negative electrode slurry containing metal wires includes the following steps:

[0119] The negative active material, the conductive agent, and the thickening agent are added to the negative electrode solvent and mixed in a planetary mixer, and then the negative electrode binder and the metal wire are added and uniformly stirred to obtain the negative electrode slurry containing metal wires.

[0120] The application also provides a negative electrode tab without a current collector, and the preparation method thereof includes the following steps:

[0121] The negative electrode slurry containing metal wires prepared in the above-mentioned embodiment 2 is coated on the surface of the separator, a copper foil with a thickness of 5 mu m is placed as a negative electrode tab at the edge of the positive electrode slurry, the copper foil and the negative electrode slurry overlap by 2 mm (i.e. Figure 2 The separator overlaps by 2 m in the length direction (i.e. left and right directions), and is dried in a drying box to form a negative active material layer. The surface density of the negative electrode slurry after drying is 0.995 g / 100 cm 2 A negative electrode tab without a current collector is obtained.

[0122] The separator is a PE separator containing an aluminum trioxide coating (i.e. the PE separator is coated with an aluminum trioxide coating, purchased from Yunnan Enxin New Material Co., Ltd., and the negative electrode slurry is coated on the surface of the aluminum trioxide coating), the thickness of the PE separator is 5 mu m, and the thickness of the aluminum trioxide coating is 2 mu m.

[0123] Embodiment 3

[0124] The application provides a battery without a current collector, and the preparation method thereof is as follows:

[0125] S1, the positive electrode tab without a current collector in embodiment 1 and the negative electrode tab without a current collector in embodiment 2 are rolled, and then 17 layers are stacked in turn, all the positive electrode tabs are welded together, all the negative electrode tabs are welded together, and are respectively welded to the external tabs to form a bare battery cell;

[0126] S2, the bare battery cell is placed in an aluminum plastic film and top side sealed to form a dry battery cell;

[0127] S3, the dry battery cell is injected with electrolyte after drying and passing moisture qualification, then is formed into a finished battery cell after formation and capacity grading, to obtain a battery without a current collector;

[0128] The electrolyte comprises 15% of electrolyte salt and 85% of organic solvent by mass fraction, the electrolyte salt is LiPF6, and the organic solvent comprises a mixed solvent of EC and DEC, and the volume ratio of EC to DEC is 1:1.

[0129] Comparative Example 1

[0130] The comparative example provides a positive electrode slurry comprising a positive electrode active material, a conductive agent, a binder, and a positive electrode solvent;

[0131] The positive electrode active material is lithium cobaltate, the conductive agent is carbon nanotube, the binder is PVDF, and the positive electrode solvent is NMP.

[0132] The mass ratio of the positive electrode active material, the conductive agent, the binder, and the positive electrode solvent is 98.2:0.8:1.0:60.

[0133] The preparation method of the positive electrode slurry comprises the following steps:

[0134] The positive electrode active material, the conductive agent, and the binder are added to the positive electrode solvent and mixed in a planetary mixer to obtain the positive electrode slurry.

[0135] The comparative example also provides a positive electrode tab, and the preparation method thereof comprises the following steps:

[0136] The positive electrode slurry prepared in Comparative Example 1 is coated on an aluminum foil (as a positive electrode current collector) with a thickness of 10 μm, and dried in a drying box to form a positive electrode active material layer, and the positive electrode slurry surface density after drying is 1.74 g / 100 cm 2 The positive electrode tab is obtained, and the aluminum foil part without the active material layer is cut into a foil tab by laser.

[0137] The comparative example also provides a negative electrode slurry comprising a negative electrode active material, a conductive agent, a thickening agent, a binder, and a negative electrode solvent;

[0138] The negative electrode active material is artificial graphite, the conductive agent is conductive carbon black, the thickening agent is CMC, the binder is SBR, and the negative electrode solvent is water.

[0139] The mass ratio of the negative electrode active material, the conductive agent, the thickening agent, the binder, and the negative electrode solvent is 97.2:0.4:1.1:1.3:75.

[0140] The preparation method of the negative electrode slurry comprises the following steps:

[0141] The negative active material, the conductive agent, and the thickening agent are added into the negative solvent, and mixed in a planetary mixer, and then the binder is added, and the mixing is continued to obtain a negative slurry.

[0142] The present comparative example also provides a negative electrode sheet, and a preparation method thereof includes the following steps:

[0143] The negative slurry prepared in the above Comparative Example 1 is coated on a copper foil (as a negative current collector) with a thickness of 5 μm, and dried in a drying oven to form a negative active material layer, i.e., a negative electrode sheet. The areal density of the negative slurry after drying is 0.995 g / 100 cm 2 The foil tabs are cut out from the copper foil by laser cutting.

[0144] The present comparative example also provides a battery, and a preparation method thereof includes the following steps:

[0145] S1, the positive electrode sheet and the negative electrode sheet in Comparative Example 1 are stacked in the order of positive electrode sheet, separator, negative electrode sheet, and separator, and the number of layers is 17. All the positive electrode tabs are welded together, and all the negative electrode tabs are welded together and welded to the external tabs, respectively, to form a bare cell;

[0146] S2, the bare cell is placed in an aluminum-plastic film, and then top side sealing is performed to form a dry cell;

[0147] S3, the dry cell is dried, and then electrolyte is injected after the moisture content is qualified. Then, the cell is formed, and a finished cell is obtained to form a battery;

[0148] The electrolyte includes 15% of electrolyte salt and 85% of organic solvent by mass fraction. The electrolyte salt is LiPF6, and the organic solvent includes a mixed solvent of EC and DEC, and the volume ratio of EC to DEC is 1:1.

[0149] The batteries without current collector in Example 3 and the batteries in Comparative Example 1 are tested for performance, and the results are shown in Table 1.

[0150] Table 1-Performance of the batteries in Example 3 and Comparative Example 1

[0151] Comparative Example 1 Example 3 Positive electrode surface density (g / 100 cm 2 )]]> 1.74 1.74 Positive electrode layer number 17 17 Average thickness of battery (mm) 4.55 4.26 Positive electrode sheet resistivity (Ω·cm) 37.3 2.9 Volume energy density (Wh / L) 738 767 Weight energy density (Wh / kg) 301 340 3C / 1C rate 97.32％ 96.88％ -20℃ low temperature discharge retention rate 65.89％ 66.23％ Room temperature 1C cycle 600 times capacity retention rate 91.28％ 91.37％

[0152] As can be seen from Table 1, the positive electrode sheet resistivity of the battery without current collector in Example 3 is reduced from 37.3 Ω·cm to 2.9 Ω·cm compared with the battery in Comparative Example 1. The volume energy density and the mass energy density of the battery without current collector in Example 3 are greatly improved compared with the battery in Comparative Example 1, and the rate performance, the low-temperature discharge performance, and the cycle performance are equivalent.

[0153] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A current-free battery, comprising at least one current-free positive electrode and at least one current-free negative electrode; The positive electrode without current collector and the negative electrode without current collector are stacked alternately. The positive electrode without current collector includes: A separator, wherein a positive electrode active material layer is provided on the surface of the separator, wherein the positive electrode active material layer is obtained by coating a positive electrode slurry containing metal wires onto the surface of the separator and drying it; The positive electrode tab is located on one side of the positive electrode active material layer; The positive electrode slurry containing metal wires includes positive electrode active material, conductive agent, positive electrode binder, positive electrode solvent and metal wires; The positive electrode active material is lithium cobalt oxide; the conductive agent is carbon nanotubes; the positive electrode binder is PVDF; the positive electrode solvent is NMP; the metal wire is aluminum metal wire with a diameter of 5μm and an aspect ratio of 500. The mass ratio of the positive electrode active material, conductive agent, positive electrode binder, positive electrode solvent, and metal wire is 98.2:0.6:1.0:60:0.2; Negative electrode plates without current collectors include: A separator, wherein a negative electrode active material layer is provided on the surface of the separator, wherein the negative electrode active material layer is obtained by coating a negative electrode slurry containing metal wires onto the surface of the separator and drying it; The negative electrode tab is located on one side of the negative electrode active material layer; The negative electrode slurry containing metal wires includes negative electrode active material, conductive agent, thickener, negative electrode binder, negative electrode solvent, and metal wires. The negative electrode active material is artificial graphite; the conductive agent is conductive carbon black; the thickener is CMC; the negative electrode binder is SBR; the negative electrode solvent is water; the metal wire is copper metal wire with a diameter of 3μm and an aspect ratio of 1000. The mass ratio of negative electrode active material, conductive agent, thickener, negative electrode binder, negative electrode solvent, and metal wire is 97.2:0.3:1.1:1.3:75:0.1; The diaphragm is a PE diaphragm with an aluminum oxide coating. The thickness of the PE diaphragm is 5μm, and the thickness of the aluminum oxide coating is 2μm.

2. The current collector-free battery as claimed in claim 1, characterized in that, The positive electrode tab includes at least one of aluminum foil, aluminum sheet, aluminum foam, and aluminum wire; The negative electrode tab includes at least one of nickel foil, nickel sheet, nickel wire, nickel foam, copper foil, copper sheet, copper wire, copper foam, aluminum foil, aluminum sheet, aluminum foam, and aluminum wire.

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