Battery

Abstract

Provided in the present disclosure is a battery. The battery comprises: an electrolyte, and a battery component in contact with the electrolyte; at least the surface of the battery component in contact with the electrolyte comprises a stainless steel layer, the electrolyte at least comprises a compound represented by formula 1, and the compound represented by formula 1 is: Formula 1.

Description

Battery

[0001] This application claims priority to the Chinese patent application No. 202411291387.0, filed on September 14, 2024, and entitled "Battery", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application belongs to the technical field of batteries, and in particular relates to a battery. BACKGROUND

[0003] Lithium ion batteries are widely used due to their high energy density, long cycle life, and high safety. According to the packaging type, lithium ion batteries can be divided into soft package batteries, square aluminum shell batteries, and cylindrical batteries.

[0004] Taking cylindrical batteries as an example, cylindrical batteries have higher volumetric energy density and mature manufacturing processes, and are preferred for use in passenger car power batteries. However, some welding parts of the battery components will damage the coating of some stainless steel materials due to welding operations, and when the electrolyte contacts these parts, it is easy to cause side reactions at the battery welding points, resulting in a decrease in battery performance.

[0005] SUMMARY

[0006] In a first aspect of the present application, a battery is provided, comprising: an electrolyte, a battery component in contact with the electrolyte; the contact surface of the battery component at least includes a stainless steel layer, and the electrolyte at least includes a compound represented by Formula 1, and the compound represented by Formula 1 is:

[0007] wherein m is an integer from 0 to 3, n is an integer from 0 to 3, m and n are not 0 at the same time, p is an integer from 1 to 5, R0 is a single bond or a methylene group, R1 is hydrogen, halogen, a hydrocarbon group with 1-5 carbon atoms, or a halogenated hydrocarbon group with 1-5 carbon atoms, R2, R3, and R4 are independently

[0008] The compound represented by Formula 1 can form a passivation layer on the surface of the stainless steel layer, which is beneficial to reduce or avoid side reactions between the damaged coating stainless steel layer and the electrolyte, so that the battery has good cycle stability.

[0009] In some embodiments, the compound represented by Formula 1 is at least one selected from the group consisting of:

[0010]

[0011] ​In some embodiments, the mass percentage of the compound of formula 1 in the electrolyte is 0.02% to 10%.

[0012] In some embodiments, the battery includes a shell and / or a cover plate, and further includes a negative current collector, and the battery component includes a portion of the shell and / or the cover plate welded to the negative current collector, and the portion includes a stainless steel layer.

[0013] In some embodiments, the cross-sectional area of the portion of the shell and / or the cover plate welded to the negative current collector is 5mm 2 to 400mm 2 .

[0014] In some embodiments, the battery includes a cylindrical battery.

[0015] In some embodiments, the cylindrical battery has a shell outer diameter of 20mm to 65mm.

[0016] In some embodiments, the electrolyte satisfies at least one of the following (1) to (3):

[0017] (1) The electrolyte contains a solvent, and the solvent includes at least one of a carbonate-based solvent, a carboxylic acid ester-based solvent, an ether-based compound solvent, a phosphorus-containing compound-based solvent, a sulfur-containing compound-based solvent, and an aromatic fluorine-containing compound-based solvent;

[0018] (2) The electrolyte contains an electrically conductive salt, and the electrically conductive salt includes at least one of lithium hexafluorophosphate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethylsulfonylimide, sodium hexafluorophosphate, sodium bisfluorosulfonylimide, and sodium bis-trifluoromethylsulfonylimide;

[0019] (3) The electrolyte contains an additive, and the additive includes at least one of vinylene carbonate, fluoroethylene carbonate, vinyl ethylene carbonate, and succinic anhydride.

[0020] In some embodiments, the battery further includes a positive active material, and the positive active material includes at least one of lithium iron phosphate, lithium cobaltate, ternary material LiNi x Co y MnzO2, lithium iron manganese phosphate material, lithium-rich manganese-based material xLi2MnO3·(1-x)LiMO2, lithium nickel manganese acid, lithium manganate, sodium iron phosphate material, three-dimensional tunnel type Na 0.44 MnO2, P2 layered type NaMO2, NaFePO4, Na4Fe3(PO4)2P2O7, Na3V2(PO4)3, Na3V2(PO4)2F3, Na2Fe(CN)6, Na2MnFe(CN)6.

[0021] In some embodiments, the battery further includes a negative electrode material including at least one of graphite, hard carbon, a silicon-containing compound, and silicon. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0023] FIG. 1 is a schematic view of a cylindrical battery structure according to some embodiments of the present application.

[0024] FIG. 2 is a schematic view of a cover plate structure.

[0025] FIG. 3 is a partial cross-sectional view of a cover plate.

[0026] FIG. 4 is a schematic view of a welding spot.

[0027] BRIEF DESCRIPTION OF DRAWINGS DETAILED DESCRIPTION

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application; and various parameters recited in the description herein can be measured using any measuring method conventionally used in the art (e.g., can be tested according to the methods given in the examples of the present application), unless otherwise stated.

[0029] The terms "comprise" and "have" and any variations thereof used in the specification and claims of the present application are open-ended transitional phrases, i.e., include the contents designated in the present application, but do not exclude other contents.

[0030] In the description of the present application, all numbers disclosed herein are approximate. Each numerical value should be construed in light of the ordinary skill in the art and the understanding that a value that is approximately the same when compared to a referenced value can be the desired value.

[0031] The solutions of the present application will be explained below with reference to the examples. Those skilled in the art will understand that the examples below are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. If the specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or according to the product instructions are used. If the reagents or instruments are not specified by the manufacturer, they are all conventional products that can be obtained commercially.

[0032] The first aspect of the embodiments of the present application provides a battery, comprising an electrolyte, a battery component in contact with the electrolyte; at least the contact surface of the battery component with the electrolyte comprises a stainless steel layer, and the electrolyte comprises at least a compound represented by Formula 1:

[0033] wherein m is an integer of 0-3, n is an integer of 0-3, m and n are not 0 at the same time, p is an integer of 1-5, R0 is a single bond or a methylene group, R1 is hydrogen, halogen, a hydrocarbon group with 1-5 carbon atoms or a halogenated hydrocarbon group with 1-5 carbon atoms, R2, R3 and R4 are independently

[0034] Some components (such as the shell and / or the cover plate) of some batteries (such as cylindrical batteries) are made of stainless steel. Generally, the surface layer of these components has a nickel plating layer to protect the stainless steel layer, which can effectively prevent the reaction with the electrolyte. However, when the nickel plating layer on the surface of the stainless steel layer of the battery component in contact with the electrolyte is damaged, the stainless steel layer is directly exposed to the electrolyte, which will cause serious corrosion of the stainless steel layer when the battery is charging and discharging. At the same time, the electrolyte is decomposed in large quantities, resulting in poor cycle stability of the battery.

[0035] The compound represented by Formula 1 in the embodiments of the present application can form a passivation layer on the surface of the stainless steel layer, which can effectively avoid the direct contact of the electrolyte with the stainless steel layer, inhibit the corrosion of the stainless steel layer, and avoid the continuous decomposition of the electrolyte, so that the battery has good cycle stability.

[0036] In the embodiments of the present application, the compound represented by Formula 1 has strong electronegativity, strong binding energy with the stainless steel layer, and is adsorbed on the surface layer of the stainless steel to promote the formation of the passivation layer. The compound represented by Formula 1 can form a network structure passivation layer on the surface of the stainless steel layer, which has high compactness and can effectively avoid the direct contact of other components of the electrolyte with the stainless steel layer, inhibit the corrosion of the stainless steel layer, and avoid the continuous decomposition of the electrolyte, so that the battery provided by the embodiments of the present application has good cycle stability. In addition, the three-dimensional network structure passivation layer formed by the compound represented by Formula 1 has high stability and can be used to protect the continuous interface and the large interface of the stainless steel surface.

[0037] In the embodiments of the present application, the compound shown in formula 1 can be directly added to the electrolyte, and the electrolyte is injected into the battery. In the process of battery formation or battery operation, the stainless steel surface layer, if any, reacts with the compound shown in formula 1 to form a passivation layer as a protective layer. The elements in the passivation layer include sulfur.

[0038] In some embodiments, the compound shown in formula 1 is selected from at least one of:

[0039]

[0040] In some embodiments, the mass fraction of the compound shown in formula 1 in the electrolyte is 0.02% to 10%. In specific examples, the mass fraction of the compound shown in formula 1 is 0.02%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, etc.

[0041] In the embodiments of the present application, the mass fraction of the compound shown in formula 1 in the electrolyte is 0.02% to 10%, which is the content of the compound shown in formula 1 in the initial state of the electrolyte. At this time, it has not yet been used to form a passivation layer. This amount is beneficial on the one hand to form a passivation layer of effective thickness on the surface of the stainless steel, avoiding the decomposition of electrolyte components and thus deteriorating the cycle performance; on the other hand, it is beneficial to ensure that the electrolyte maintains a high electrical conductivity.

[0042] In some embodiments, the battery includes a shell and / or a cover plate, and further includes a negative current collector. The battery components include a part of the shell and / or the cover plate that is welded to the negative current collector, and the part includes a stainless steel layer.

[0043] In the embodiments of the present application, the shell and / or the cover plate of the battery are made of stainless steel, and the surface of the stainless steel has a nickel plating layer. However, when the shell and / or the cover plate of the battery are welded to the negative current collector by welding, the nickel plating layer on the surface of the stainless steel is destroyed and then integrated with the negative current collector to form a welding point. The welding point is directly in contact with the electrolyte without the protection of the nickel plating layer, which can easily cause the cover plate to be corroded by the electrolyte and consume the electrolyte, resulting in poor cycle stability. In the embodiments of the present application, the compound shown in formula 1 forms a passivation layer at the welding connection part, which can prevent the welding connection part from continuing to contact the electrolyte, prevent the welding part from being corroded by the electrolyte, and avoid the electrolyte from being consumed in large quantities, thereby improving the electrochemical performance of the battery.

[0044] In addition, the part of the shell and / or the cover plate that is welded to the negative current collector has a high current density and a low potential, which can further promote the reduction of the compound shown in formula 1 to form a reticular structure of the passivation plating layer.

[0045] ​In some embodiments, the cross-sectional area of the part of the shell and / or the cover plate where the negative current collector is welded is 5mm 2 ~400mm 2 .

[0046] In specific examples, the cross-sectional area of the part of the shell and / or the cover plate where the negative current collector is welded is 5mm 2 , 10mm 2 , 50mm 2 , 100mm 2 , 150mm 2 , 200mm 2 , 250mm 2 , 300mm 2 , 350mm 2 , or 400mm 2 , etc.

[0047] In the embodiments of the present application, the cross-sectional area of the welded part affects the amount of the compound represented by Formula 1 and the electrochemical performance of the battery. The larger the cross-sectional area of the welded part, the more the compound represented by Formula 1 is needed. In particular, when a passivation layer is formed by adding the compound represented by Formula 1 to the electrolyte, the cross-sectional area of the welded part in the embodiments of the present application is 5mm 2 ~400mm 2 . By adding an appropriate amount of the compound represented by Formula 1 to the electrolyte, a passivation layer can be formed on the full coverage cross-sectional position, and the ionic conductivity of the electrolyte will not be increased, thereby ensuring that the battery has high electrochemical performance.

[0048] Further, the cross-sectional area of the part of the shell and / or the cover plate where the negative current collector is welded is 30mm 2 ~300mm 2 . In specific examples, the cross-sectional area of the part of the shell and / or the cover plate where the negative current collector is welded is 30mm 2 , 60mm 2 , 90mm 2 , 120mm 2 , 160mm 2 , 190mm 2 , 210mm 2 , 240mm 2 , 270mm 2 , or 300mm 2 , etc.

[0049] The embodiments of the present application provide that the cross-sectional area of the part of the shell and / or the cover plate where the negative current collector is welded is 30mm 2 ~300mm 2 , which is conducive to further obtaining a battery with high electrochemical performance.

[0050] Further, the welding method used in the welding connection is laser welding.

[0051] In the embodiments of the present application, the negative current collector is connected to the shell and / or cover plate of the battery by laser welding. This welding method causes greater damage to the nickel plating layer on the surface of the stainless steel layer.

[0052] In some embodiments, the battery includes a cylindrical battery.

[0053] Cylindrical batteries have higher volumetric energy density and mature manufacturing processes, and are therefore preferred for use in passenger vehicle power batteries. However, as people's requirements for battery energy density and charging speed continue to increase, the size of cylindrical batteries continues to increase, and the number of negative current collectors (also referred to as tabs) continues to increase, resulting in an increase in the welding area of the negative current collector and the battery shell portion (such as the negative pole) and the like. When the electrolyte comes into contact with these portions, it is easy to cause corrosion of the battery welding points and continuous consumption and decomposition of the electrolyte, resulting in a decrease in battery performance. Therefore, the cylindrical battery provided in the embodiments of the present application has greater practical application value.

[0054] In some embodiments, the shell of the cylindrical battery has an outer diameter of 20 mm to 65 mm.

[0055] In specific examples, the shell of the cylindrical battery has an outer diameter of 20 mm, 25 mm, 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, 42 mm, 44 mm, 46 mm, 48 mm, 50 mm, 55 mm, 60 mm, or 65 mm, etc.

[0056] The cylindrical battery provided in the embodiments of the present application has a shell outer diameter of 30 mm to 55 mm, which can ensure a high energy density while keeping the discharge temperature rise of the battery low, and does not increase the difficulty of the PACK (Package) of the battery.

[0057] In some embodiments, the battery further includes a winding core, and the winding core includes a positive electrode sheet, a negative electrode sheet, and a separator.

[0058] The cylindrical battery has a structure known in the art, and as an example, a structure diagram of the cylindrical battery is provided as shown in FIG. 1, and a cover plate structure diagram is provided as shown in FIGS. 2-4. The cylindrical battery 1 includes a shell 300 and a roll core 500 contained in the shell 300, and a negative electrode current collector 6 and a cover plate 100 are mounted on the shell 300 at the negative electrode side of the cylindrical battery. The cover plate 100 includes a cover plate base body 10, a first hole 111, a second hole 113 and a third hole 115 are sequentially arranged coaxially in the center position of the cover plate base body 10, and the first hole 111, the second hole 113 and the third hole 115 form a liquid injection hole 11. The cover plate base body 10 is also provided with an anti-explosion groove 70, which is coaxially arranged with the liquid injection hole 11. The cover plate base body 10 is also provided with a plurality of grooves 50, all of which are uniformly arranged in a circular array with the liquid injection hole 11 as the center; a abutting portion 30 is also provided downwardly at the bottom of the groove 50, which is welded and connected with the negative electrode current collector 6. As shown in FIG. 4, the abutting portion 30 and the negative electrode current collector 6 are welded and connected by a plurality of welding points 700. Since the cover plate 100 is made of stainless steel, the surface of the stainless steel has a nickel plating layer. When the cover plate 100 and the negative electrode current collector 6 of the cylindrical battery 1 are welded and connected by welding, the nickel plating layer on the surface of the stainless steel will be damaged and then integrated with the negative electrode current collector 6 to form the welding points 700. The position of the welding points 700 is directly in contact with the electrolyte without the protection of the nickel plating layer, which is easy to cause the cover plate 100 to be corroded by the electrolyte and consume the electrolyte, resulting in poor cycle stability. The compound shown in formula 1 is used to form a passivation layer at the welding connection position in the embodiment of the application, which can prevent the welding connection position from continuing to contact with the electrolyte, prevent the welding position from being corroded by the electrolyte, avoid the electrolyte from being consumed in large amount, and is beneficial to improve the electrochemical performance of the battery.

[0059] Further, the negative electrode sheet includes a negative electrode active material layer and a negative electrode current collector, and the negative electrode active material layer covers one side or both sides of the negative electrode current collector.

[0060] Further, the negative electrode active material layer includes a negative electrode active material, a negative electrode binder and a negative electrode conductive agent.

[0061] Further, the mass ratio content of each component in the negative electrode active material layer is: 90%-99% of the negative electrode active material, 0-5% of the negative electrode conductive agent and 1%-10% of the negative electrode binder.

[0062] Further, the negative electrode active material includes at least one of graphite, hard carbon, a silicon-containing compound and silicon.

[0063] Further, the negative electrode binder includes at least one of sodium carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), polyvinyl chloride, carboxylated polyvinyl chloride, polyfluorinated ethylene, an oxirane-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyvinyl alcohol, and sodium polyacrylate.

[0064] Further, the negative electrode conductive agent includes at least one of natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, and graphene.

[0065] Further, the negative electrode current collector includes at least one of a copper foil, a composite copper foil, a foamed nickel, a foamed copper, and an aluminum foil.

[0066] Further, the positive electrode sheet includes a positive electrode active material layer and a positive electrode current collector, and the positive electrode active material layer covers one side or both sides of the surface of the positive electrode current collector.

[0067] Further, the positive electrode active material layer includes a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent.

[0068] Further, the mass ratio content of each component in the positive electrode active material layer is 90% to 99.5% of the positive electrode active material, 0.25% to 5% of the positive electrode conductive agent, and 0.25% to 5% of the positive electrode binder.

[0069] Further, the positive electrode active material includes at least one of lithium iron phosphate (LiFePO4), lithium cobalt oxide (LiCoO2), a ternary material (LiNi x Co y Mn z O2(x+y+z=1)), a lithium manganese iron phosphate material, a lithium-rich manganese-based material (xLi2MnO3·(1-x)LiMO2), lithium nickel manganese phosphate (LiNi 0.5 Mn 1.5 O4), lithium manganate (LiMn2O4), a sodium iron phosphate material, a three-dimensional tunnel-type Na 0.44 MnO2, a P2 layered-type NaMO2 (M is one, two, or three of Ni, Mn, and Fe), NaFePO4, Na4Fe3(PO4)2P2O7, Na3V2(PO4)3, Na3V2(PO4)2F3, Na2Fe(CN)6, and Na2MnFe(CN)6.

[0070] Further, the positive electrode binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride (PVDF), polyfluorinated ethylene, polyethylene, polypropylene, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, an oxirane-containing polymer, polyvinylpyrrolidone, and polyurethane.

[0071] Further, the positive electrode conductive agent includes at least one of carbon black, acetylene black, graphene, ketjen black, and carbon fiber.

[0072] Further, the positive electrode current collector includes at least one of aluminum foil, composite aluminum foil, and nickel foil.

[0073] Further, the material of the separator is not limited, and can be selected by those skilled in the art according to actual needs. Further, in the embodiments of the present application, the material of the separator includes at least one of coated or uncoated polypropylene (PP) separator, polyethylene (PE) separator, and polyvinylidene fluoride separator.

[0074] In some embodiments, the electrolyte satisfies at least one of the following (1)-(3):

[0075] (1) the electrolyte contains a solvent, and the solvent includes at least one of a carbonate solvent, a carboxylic acid ester solvent, an ether compound solvent, a phosphorus compound-containing solvent, a sulfur compound-containing solvent, and an aromatic fluorine-containing compound solvent;

[0076] (2) the electrolyte contains a conductive salt, and the conductive salt includes at least one of lithium hexafluorophosphate (LiPF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethylsulfonylimide, sodium hexafluorophosphate (NaPF6), sodium bisfluorosulfonylimide (NaFSI), and sodium bis-trifluoromethylsulfonylimide;

[0077] (3) the electrolyte contains an additive, and the additive includes at least one of vinylene carbonate (VC), fluoroethylene carbonate (FEC), vinyl ethylene carbonate (VEC), and succinic anhydride (SA).

[0078] In some embodiments, the solvent in the electrolyte includes at least one of ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), methyl ethyl carbonate (EMC), fluoroethylene carbonate (FEC), propyl butyrate (PB), ethyl butyrate (EB), propyl propionate (PP), ethyl propionate (EP), methyl propionate (MP), propyl acetate (PA), fluorobenzene (FB), ethyl acetate (EA), methyl acetate (MA), propyl formate (PF), ethyl formate (EF), methyl formate (MF), and γ-butyrolactone.

[0079] In some embodiments, the conductive salt in the electrolyte accounts for 10%-20% of the total mass of the electrolyte.

[0080] In the embodiments of the present application, the conductive salt in the electrolyte accounts for 10%-20% of the total mass of the electrolyte, which is beneficial to further improve the electrochemical performance of the battery, so as to achieve higher electrical conductivity and chemical stability.

[0081] The second aspect of the application provides a method for manufacturing the above-mentioned battery, comprising: adding the compound shown in Formula 1 to the electrolyte; and after the electrolyte contacts the surface layer of the stainless steel, the compound shown in Formula 1 forms a passivation layer on the surface layer of the stainless steel.

[0082] In the embodiments of the application, the compound shown in Formula 1 is directly added to the electrolyte, which is beneficial to simplifying the manufacturing process of the battery, reducing the operation difficulty, and saving the cost.

[0083] In some embodiments, the mass percentage of the compound shown in Formula 1 in the electrolyte is 0.02% to 10%. In specific examples, the mass percentage of the compound shown in Formula 1 is 0.02%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, etc.

[0084] In the embodiments of the application, the mass percentage of the compound shown in Formula 1 in the electrolyte is 0.02% to 10%, which is the content of the compound shown in Formula 1 in the initial state of the electrolyte, and the compound has not been used to form the passivation layer at this time. The addition amount is beneficial to forming the passivation layer with an effective thickness on the surface layer of the stainless steel, avoiding the decomposition of the electrolyte components and thus deteriorating the cycle performance, and is also beneficial to ensuring that the electrolyte maintains a relatively high conductivity.

[0085] In some embodiments, the conditions for the compound shown in Formula 1 to form the passivation layer include that the temperature is the required temperature for the formation of the battery. The specific temperature can be selected based on the actual situation. In specific examples, the conditions for the compound shown in Formula 1 to polymerize to form the passivation layer include that the temperature is 20°C to 60°C; more specifically, the temperature is 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, etc.

[0086] In some embodiments, the conditions for the compound shown in Formula 1 to polymerize to form the passivation layer include that the temperature is 20°C to 45°C; in specific examples, the temperature is 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 44°C, or 45°C, etc.

[0087] In the embodiments of the application, the conditions for the compound shown in Formula 1 to polymerize to form the passivation layer satisfy the above-mentioned temperature conditions, the viscosity of the electrolyte is relatively small, which is beneficial to the rapid polymerization of the compound and the formation of the passivation layer with a relatively high compactness; at the same time, the temperature conditions satisfy the above-mentioned temperature conditions, which avoids the thermal shrinkage of the separator of the battery cell and affects the performance of the battery.

[0088] In some embodiments, the compound shown in Formula 1 polymerizes to form the passivation layer when the battery is charged for the first time, or the compound forms the passivation layer during the operation of the battery.

[0089] The third aspect of the embodiments of the present application provides a power consuming device comprising the battery or the battery manufactured by the manufacturing method.

[0090] The battery provided by the embodiments of the present application forms a passivation layer on the surface of the stainless steel layer of the battery component in contact with the electrolyte, prevents the battery component from being corroded by the electrolyte, avoids large consumption of the electrolyte, and is beneficial to obtain a battery with high electrochemical performance.

[0091] In specific examples, the power consuming device includes 3C digital, household appliances, passenger cars, unmanned aerial vehicles or electric aircraft, etc.

[0092] The fourth aspect of the embodiments of the present application provides a new use of the compound shown in formula 1 for forming a passivation layer on the surface of the stainless steel layer to prevent the battery component in contact with the electrolyte from reacting with the electrolyte; the contact surface of the battery component in contact with the electrolyte at least includes the stainless steel layer; the compound shown in formula 1 is:

[0093] wherein m is an integer of 0-3, n is an integer of 0-3, m and n are not 0 at the same time, p is an integer of 1-5, R0 is a single bond or a methylene group, R1 is hydrogen, halogen, a hydrocarbon group with 1-5 carbon atoms or a halogenated hydrocarbon group with 1-5 carbon atoms, R2, R3 and R4 are independently

[0094] Some components of the battery (as an example, which can be a shell, can also be a cover plate, and can also be a shell and a cover plate) are made of stainless steel material, usually, the surface layer of these components has a nickel plating layer to protect the stainless steel layer, which can effectively prevent the reaction with the electrolyte in contact. However, when the nickel plating layer on the surface of the stainless steel layer of the battery component in contact with the electrolyte is damaged, the stainless steel layer is directly exposed to the electrolyte, and when the battery is in the charging and discharging process, the electrolyte will corrode the stainless steel layer and cause serious corrosion. At the same time, the electrolyte is decomposed in large quantities, resulting in poor cycle stability of the battery.

[0095] The embodiments of the present application use the compound shown in formula 1 to form a passivation layer on the surface of the stainless steel layer, which can avoid direct contact of the electrolyte with the stainless steel layer, inhibit corrosion of the stainless steel layer, and avoid continuous decomposition of the electrolyte, so that the battery has good cycle stability.

[0096] In the embodiments of the present application, the compound represented by formula 1 has strong electronegativity, has strong binding energy with the stainless steel layer, is adsorbed on the surface of the stainless steel layer, and promotes the formation of the passivation layer; the compound represented by formula 1 can form a reticular structure passivation layer on the surface of the stainless steel layer, the passivation layer has high compactness, can effectively avoid direct contact of other components of the electrolyte with the stainless steel layer, is beneficial to inhibiting corrosion of the stainless steel layer, and at the same time avoids continuous decomposition of the electrolyte, so that the battery provided in the embodiments of the present application has good cycle stability; in addition, the passivation layer formed by the compound represented by formula 1 has high stability, and can be applied to the protection of the continuous interface and the large interface of the stainless steel surface.

[0097] In some embodiments, the compound represented by formula 1 is selected from at least one of:

[0098]

[0099] The compound represented by formula 1-1 to formula 1-10 provided in the embodiments of the present application is beneficial to forming a passivation layer on the stainless steel surface of the battery component, protecting the battery component, avoiding a large amount of electrolyte from being consumed, and improving the electrochemical performance of the battery.

[0100] The scheme of the present application is described below through specific embodiments. It should be noted that the following embodiments are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the embodiments, the technology or condition is performed according to the technology or condition described in the literature in the art or according to the product instruction. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by market purchase.

[0101] Embodiment 1

[0102] The present embodiment provides a cylindrical lithium battery, and the specific preparation method is as follows:

[0103] (1) Preparation of electrolyte: under an inert atmosphere (moisture <0.1 ppm, oxygen <1 ppm), ethylene carbonate (EC), methyl ethyl carbonate (EMC) and ethyl acetate (EA) are mixed in a mass ratio of EC: EMC: EA = 30:60:10, and after uniform mixing, lithium bisfluorosulfonylimide salt (LiFSI) and lithium hexafluorophosphate (LiPF6) are added, the mass ratio of LiFSI in the electrolyte is 5wt%, and the mass ratio of LiPF6 in the electrolyte is 9wt%. Then, the compound represented by formula 1-1 is added, and the mass ratio of the compound represented by formula 1-1 in the electrolyte is 0.5wt%, and finally the electrolyte is obtained.

[0104] ​(2) Preparation of positive electrode sheet: lithium iron phosphate positive active material, conductive agent acetylene black and binder polyvinylidene fluoride (PVDF) were dispersed in N-methyl pyrrolidone (NMP) solvent at a mass ratio of 96:2:2, and fully stirred and mixed to form a uniform positive electrode slurry; the positive electrode slurry was uniformly coated on the positive electrode current collector aluminum foil, and then dried, rolled and cut to obtain the positive electrode sheet.

[0105] (3) Preparation of negative electrode sheet: negative active material graphite, conductive agent acetylene black, binder sodium carboxymethyl cellulose (CMC) and butadiene rubber (SBR) were dispersed in deionized water at a mass ratio of 95:2:2:1, and fully stirred and mixed to form a uniform negative electrode slurry; the negative electrode slurry was uniformly coated on the negative electrode current collector copper foil, and then dried, rolled and cut to obtain the negative electrode sheet.

[0106] (4) Preparation of separator: 16 μm thick base material PE separator.

[0107] (5) Preparation of battery: the positive electrode sheet, the separator and the negative electrode sheet were wound to obtain a roll core, wherein the separator was between the positive electrode sheet and the negative electrode sheet to play a role of isolation, and the roll core was placed in a shell (material: nickel-plated stainless steel), and the negative electrode current collector and the cover plate were welded together by laser welding. The cross-sectional area of all welding sites (i.e. all welding points) was 144 mm 2 , and the outer diameter of the shell was 46 mm. After drying, electrolyte was injected. After standing, the battery was prepared by charging the core to 3.6 V at 0.1 C under the condition of 45°C to complete formation (formation of passivation layer), and then the battery was prepared by the process of capacity distribution.

[0108] Examples 2-33

[0109] Examples 2-33 were prepared by the method of Example 1, and the specific differences are shown in Table 1.

[0110] Comparative Example 1

[0111] This comparative example provides a cylindrical lithium battery, and the specific preparation method is shown in Example 1, and the difference is that no compound shown as formula 1 is added to the electrolyte.

[0112] Comparative Example 2

[0113] This comparative example provides a cylindrical lithium battery, and the specific preparation method is shown in Example 1, and the difference is that 2.5% film-forming additive VC (Vinylene Carbonate, vinylene carbonate) is added to the electrolyte.

[0114] Comparative Example 3

[0115] The comparative example provides a cylindrical lithium battery, and the specific preparation method is shown in Example 1, and the difference is that 2.5% film-forming additive FEC (Fluoroethylene carbonate) is added to the electrolyte.

[0116] Comparative Example 4

[0117] The comparative example provides a cylindrical lithium battery, and the specific preparation method is shown in Example 1, and the difference is that 2.5% film-forming additive VEC (4-Vinyl-1,3-dioxolan-2-one) is added to the electrolyte.

[0118] The parameters described in Examples 1-33 and Comparative Examples 1-4, such as the type of compound of Formula 1, the amount of compound of Formula 1 added, and the preparation parameter conditions, are shown in Table 1.

[0119] Table 1

[0120] Performance test:

[0121] I. Test method:

[0122] 1. High temperature cycle test: Place the battery at 45°C, use 1.5C current for charge and discharge cycle, record the first three maximum discharge capacity as Q, cycle to 1000 weeks capacity as Q2, calculate the capacity retention rate of the battery after high temperature cycle by the following formula: Capacity retention rate (%) = Q2 / Q x 100.

[0123] 2. Solder corrosion: After 10 times of charge and discharge cycle at room temperature, the battery is disassembled and the solder corrosion is observed.

[0124] 3. Passivation layer element detection method: The formed battery is disassembled, the part of electrolyte in contact with stainless steel layer is cut and element detection is performed using scanning electron microscope energy dispersive spectrometer (EDS).

[0125] II. Test results

[0126] The test results are shown in Table 2.

[0127] Table 2

[0128] The test results are shown in Table 2 above. From the results listed in the table, it can be seen that, compared with the comparative examples, the EDS test results found that there was sulfur element at the contact site of the electrolyte and the stainless steel layer, indicating that there was a passivation layer on the stainless steel layer and the passivation layer was formed by the reaction of the compound represented by formula 1. The examples have a significant anticorrosion effect. In addition, the capacity retention rate after high-temperature cycling is significantly improved. At the same time, only the battery including the compound represented by formula 1 in the electrolyte can prevent the corrosion of the stainless steel, while conventional additives such as VC, FEC, etc. do not have an effect. These results show that the battery proposed in the present application has outstanding advantages.

[0129] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect as the technical idea within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the gist of the present application, various modifications that can be thought of by those skilled in the art, other modes constructed by combining part of the elements of the embodiments are also included in the scope of the present application.

Claims

1. A battery, wherein, The battery includes: an electrolyte, and a battery component in contact with the electrolyte; a contact surface of the battery component in contact with the electrolyte includes a stainless steel layer; The electrolyte comprises a compound represented by Formula 1, the compound represented by Formula 1 is: wherein m is an integer of 0 to 3, n is an integer of 0 to 3, and m and n are not 0 at the same time, p is an integer of 1 to 5, R0is a single bond or a methylene group, R1is hydrogen, a halogen, a hydrocarbon group having 1 to 5 carbon atoms, or a halogenated hydrocarbon group having 1 to 5 carbon atoms, R2, R3, R4are each independently 2. The battery of claim 1, wherein, The compound of Formula 1 is selected from: at least one of 3. The battery according to claim 1 or 2, wherein a mass percentage of the compound represented by Formula 1 in the electrolyte is 0.02% to 10%.

4. The battery of any one of claims 1-3, wherein, The battery includes a shell and / or a cover plate, and further includes a negative current collector, and the battery component includes a portion of the shell and / or the cover plate that is welded to the negative current collector, and the portion includes the stainless steel layer.

5. The battery of claim 4, wherein, The cross-sectional area of the part of the housing and / or cover plate to which the negative current collector is welded is 5mm 2 ~400mm 2 .

6. The battery of any one of claims 1-5, wherein, The battery includes a cylindrical battery.

7. The battery of claim 6, wherein, The shell of the cylindrical battery has an outer diameter of 20 mm to 65 mm.

8. The battery of any one of claims 1-7, wherein, The electrolyte satisfies at least one of the following (1) to (3): (1) the electrolyte contains a solvent, and the solvent includes at least one of a carbonate-based solvent, a carboxylic acid ester-based solvent, an ether-based compound solvent, a phosphorus-containing compound-based solvent, a sulfur-containing compound-based solvent, and an aromatic fluorine-containing compound-based solvent; (2) the electrolyte contains an electrically conductive salt, and the electrically conductive salt includes at least one of lithium hexafluorophosphate, lithium bisfluorosulfonimide, lithium bis-trifluoromethylsulfonimide, sodium hexafluorophosphate, sodium bisfluorosulfonimide, and sodium bis-trifluoromethylsulfonimide; (3) the electrolyte contains an additive, and the additive includes at least one of vinylene carbonate, fluoroethylene carbonate, vinyl ethylene carbonate, and succinic anhydride.

9. The battery of any one of claims 1-8, wherein, The battery further includes a positive active material including lithium iron phosphate, lithium cobaltate, a ternary material LiNi x Co y Mnz02, lithium manganese iron phosphate material, lithium-rich manganese-based material xLi2Mn03-(1-x)LiM02, lithium nickel manganese acid, lithium manganese acid, sodium iron phosphate material, three-dimensional tunnel type Na 0.44 Mn02, P2layer type NaM02, NaFeP04, Na4Fe3(P04)2P207, Na3V2(P04)3, Na3V2(P04)2F3, Na2Fe(CN)6, Na2MnFe(CN)6.

10. The battery of any one of claims 1-9, wherein, The battery further includes a negative electrode material, and the negative electrode material includes at least one of graphite, hard carbon, a silicon-containing compound, and silicon.

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