Lithium-carbon fluoride battery electrolyte and lithium-carbon fluoride battery

Abstract

The application discloses a lithium-carbon fluoride battery electrolyte and a lithium-carbon fluoride battery. In order to improve the long-time storage safety performance and power discharge performance of the lithium-carbon fluoride battery in a high-temperature environment and further improve the application prospect of the lithium-carbon fluoride battery, the technical scheme adopted by the application is to provide a lithium-carbon fluoride battery electrolyte which comprises an organic solvent, an electrolyte salt and an additive, wherein the electrolyte is a mixture of any one of lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, lithium bisfluorosulfonylimide, lithium trifluoromethylsulfonate and lithium difluorophosphate, and the additive comprises silane additives, acid anhydride additives and phosphazene additives in a mass ratio of (1-5):(0.5-1):(3-10). The electrolyte system of the application can obviously improve the high-temperature discharge capacity and the low-temperature discharge capacity of the lithium-carbon fluoride battery, the large-current pulse discharge capacity and the high-temperature storage safety performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium carbon fluoride batteries, and particularly relates to a lithium carbon fluoride battery electrolyte and a lithium carbon fluoride battery. BACKGROUND

[0002] The battery of a tire pressure monitoring system has very high requirements on working temperature. The theoretical working temperature range of a conventional CR series heat-resistant wide-temperature button lithium-manganese battery is-20 DEG C to +60 DEG C. If the temperature is lower than or higher than the temperature range, the performance of the battery will be greatly reduced. In some northern cities in China, the use temperature of equipment outdoors will be lower than-20 DEG C, and the ambient temperature when some vehicle-mounted equipment is used will be higher than 85 DEG C.

[0003] The lithium carbon fluoride battery is a lithium / solid positive electrode system with the highest specific energy at present, and the actual specific energy can reach 650 Wh / kg (0.01C discharge). The working voltage is about 2.5 V, the working temperature range is wide, and the battery can work in the range of-40 DEG C to +130 DEG C. The self-discharge is small, and the storage life is more than 10 years. The lithium carbon fluoride battery takes carbon fluoride as the positive electrode, and mostly takes a mixed organic solvent containing lithium tetrafluoroborate or other lithium salts as the electrolyte. The structure of the battery is similar to that of a lithium manganese dioxide battery. In the discharge process of the battery, conductive carbon is generated to increase the conductivity of the battery, thereby improving the discharge platform and efficiency of the battery. In addition to the characteristics of high temperature resistance and low temperature resistance, the lithium carbon fluoride series battery also has stable discharge capacity, and can maintain good electrical properties in a high-temperature and high-humidity environment. The discharge is stable and continuous, and the self-discharge rate is less than 1 % / year. In the production, use and scrap process of the battery, no heavy metal is involved. The physical and chemical stability of the carbon fluoride material makes the lithium carbon fluoride battery relatively safer. The battery still has high safety in the misuse conditions such as short circuit, extrusion, collision, overdischarge and high temperature. Therefore, the lithium carbon fluoride series button battery has become the first choice for a tire pressure monitoring system (TPMS) of a vehicle.

[0004] However, the density of carbon fluoride is low, the conductivity is low, and the hydrophobicity is strong. A large amount of heat will also be generated in the process of continuous large-current discharge, and the volume of the battery will expand obviously. In a long-time high-temperature environment, the risk of battery leakage and even fire and explosion is also high. These defects also limit the application of the battery to some extent. In addition, compared with a lithium secondary battery, a lithium primary battery pursues high specific energy discharge characteristics more, so that the electrolyte formula is adapted to the carbon fluoride positive electrode material, and the energy density of the carbon fluoride can be maximized. This is also the key research direction of the lithium carbon fluoride battery at present. SUMMARY

[0005] The technical problem to be solved by the application is to provide a wide-temperature lithium carbon fluoride battery electrolyte capable of improving the safety performance and power discharge performance under long-time high-temperature storage.

[0006] To achieve the above object, the technical scheme adopted by the present application is:

[0007] A lithium-carbon fluoride battery electrolyte, comprising an organic solvent, an electrolyte salt and an additive, the electrolyte being a mixture of any one of lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, lithium bisfluorosulfonylimide, lithium trifluoromethylsulfonate and lithium difluorophosphate, the additive comprising a silane additive, an acid anhydride additive and a phosphazene additive, the mass ratio of the silane additive, the acid anhydride additive and the phosphazene additive being (1-5):(0.5-1):(3-10).

[0008] Further preferably, the mass ratio of the silane additive, the acid anhydride additive and the phosphazene additive is (0.5-5):1:(3-10).

[0009] Preferably, the silane additive is one or more of difluorodiphenylsilane, tetraethenesilane and tetrakis(trimethylsilyl)silane.

[0010] Preferably, the acid anhydride additive is one or more of phthalic anhydride, citraconic anhydride, propylphosphonic anhydride and 2,3-pyridinedicarboxylic anhydride.

[0011] Preferably, the phosphazene additive is ethoxy-pentafluorocyclotriphosphazene and / or hexakis(2,2,2-trifluoroethoxy)cyclotriphosphazene.

[0012] According to some specific embodiments, the additive consists of the silane additive, the acid anhydride additive and the phosphazene additive.

[0013] Preferably, the concentration of the electrolyte salt is 1-2 mol / L, for example 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L.

[0014] Further preferably, the concentration of the lithium difluorophosphate is 0.05-0.2 mol / L, for example 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.11 mol / L, 0.12 mol / L, 0.13 mol / L, 0.14 mol / L, 0.15 mol / L, 0.16 mol / L, 0.17 mol / L, 0.18 mol / L, 0.19 mol / L, 0.2 mol / L.

[0015] Preferably, the silane-based additive is used in an amount of 0.1% to 5% of the total mass of the lithium-carbon-fluoride battery electrolyte, for example 0.1%, 0.5%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%.

[0016] Preferably, the acid anhydride-based additive is used in an amount of 0.1% to 3% of the total mass of the lithium-carbon-fluoride battery electrolyte, for example 0.1%, 0.5%, 0.15%, 0.2%, 0.25%, 0.3%.

[0017] Preferably, the phosphazene-based additive is used in an amount of 2% to 20% of the total mass of the lithium-carbon-fluoride battery electrolyte, for example 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%.

[0018] Further preferably, the silane-based additive is used in an amount of 0.5% to 5% of the total mass of the lithium-carbon-fluoride battery electrolyte, for example 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.

[0019] Further preferably, the acid anhydride-based additive is used in an amount of 0.5% to 1% of the total mass of the lithium-carbon-fluoride battery electrolyte, for example 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%.

[0020] Further preferably, the phosphazene-based additive is used in an amount of 2% to 10% of the total mass of the lithium-carbon-fluoride battery electrolyte, for example 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0021] Preferably, the organic solvent comprises an ester-based solvent, an ether-based solvent, and a sulfone-based solvent.

[0022] The ester-based solvent is a cyclic ester and / or a linear ester.

[0023] The cyclic ester-based solvent is one or more of vinyl carbonate, propylene carbonate, γ-butyrolactone.

[0024] The linear ester-based solvent is one or more of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl butyrate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate.

[0025] The ether-based solvent is one or more of dimethyl ether of ethylene glycol, dimethyl ether of diethylene glycol, dimethyl ether of triethylene glycol, dimethyl ether of tetraethylene glycol, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, tetrahydrofuran.

[0026] The sulfone solvents are one or more of ethylene sulfone, dimethyl sulfoxide, and sulfolane.

[0027] Preferably, the mass ratio of the ester solvent, ether solvent, and sulfone solvent is (1-5) : 1 : (1-3), and further preferably (1.5-3.5) : 1 : (1.5-3).

[0028] The application also provides a lithium-carbon fluoride battery, which has carbon fluoride as a positive electrode material and metal lithium as a negative electrode material, and the electrolyte of the lithium-carbon fluoride battery is the lithium-carbon fluoride battery electrolyte described above.

[0029] Preferably, the lithium-carbon fluoride battery has a shape of a button, a cylinder, a square, or a soft package.

[0030] The application also provides application of the lithium-carbon fluoride battery in a tire pressure detection system.

[0031] Compared with other processes, the application has the following advantages due to the above technical solutions:

[0032] The electrolyte prepared by optimizing and matching the electrolyte lithium salt, functional additive, and organic solvent can meet the requirements of normal-temperature discharge, high-rate discharge, high-low-temperature discharge performance, and safety performance at high temperature after being injected into the lithium-carbon fluoride battery. The adjusted electrolyte salt has high ionic conductivity, and the addition of lithium difluorophosphate can reduce the battery impedance and further improve the power performance. The addition of the three additives can help the electrolyte form a film on the surface of the positive and negative electrode materials, improve the stability of the electrolyte at high and low temperatures and the ionic conductivity at low temperatures, widen the temperature range of the battery, and inhibit the flammability of the electrolyte, greatly improving the safety performance of the battery at high temperatures. The electrolyte of the application has a wide application prospect in future lithium-carbon fluoride batteries for tire pressure. DETAILED DESCRIPTION

[0033] Although some models of the existing commercially available wide-temperature lithium-carbon fluoride batteries show a working temperature of -40℃ to +85℃ or -20℃ to +150℃, the high-temperature and low-temperature performance tests show that at -20℃ to -40℃, the batteries cannot normally discharge or can only discharge 0-15% of the discharge capacity at the same rate with poor rate performance, and the safety performance is poor after long-time high-temperature storage (many commercially available lithium-carbon fluoride batteries all have a certain degree of liquid leakage or explosion phenomenon in the 125℃ storage test for 100h).

[0034] Therefore, in order to improve the long-time storage safety performance and power discharge performance of the lithium carbon fluoride battery in a high-temperature environment, and further improve the application prospect of the lithium carbon fluoride battery, the inventors have carried out long-term research and a large number of experimental verification on the electrolyte system of the lithium carbon fluoride battery, and have adjusted the organic solvent, the additive and the lithium salt and the like. Through the optimization of the formula of the electrolyte system, the lithium carbon fluoride battery will not leak or explode when it is left for a long time in a high-temperature environment (125℃, 100h), and the safety performance is obviously improved. At the same time, the low-temperature discharge capacity at -40℃, the high-temperature discharge capacity at 85℃ and the 3A large-current pulse discharge capacity of the lithium carbon fluoride battery are all obviously improved, and the discharge performance is more excellent.

[0035] The technical solutions of the present application and the implementation process thereof will be further explained and described below in combination with examples and comparative examples. However, the present application is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the implementation conditions not mentioned are the conventional conditions in the industry. The technical features involved in each embodiment of the present application can be combined with each other as long as there is no conflict between them.

[0036] Each component of the electrolyte in the following examples and comparative examples can be obtained by market purchase.

[0037] The electrolyte in the following examples and comparative examples is used to prepare a lithium carbon fluoride button CR2450 type battery, and then the performance test is carried out. The positive electrode of the BR2450 type battery is carbon fluoride (specifically, fluorinated graphene), the negative electrode is metal lithium, the nominal voltage is 3V, the nominal capacity is 650mAH, and the size is Φ24x50mm. The battery preparation adopts the conventional technical means in the art.

[0038] The electrolyte formula of examples 1-12 and comparative examples 1-12 is as follows:

[0039] Example 1

[0040] The present embodiment provides a lithium carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (the mass ratio of the three is 30:20:50); the electrolyte lithium salt is lithium tetrafluoroborate and lithium difluorophosphate, wherein the concentration of lithium tetrafluoroborate in the electrolyte is 1mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.05mol / L; the additive is difluorodiphenylsilane, phthalic anhydride and ethoxy pentafluorocyclotriphosphazene, wherein the amount of difluorodiphenylsilane is 1% of the total mass of the electrolyte, the amount of phthalic anhydride is 0.5% of the total mass of the electrolyte, and the amount of ethoxy pentafluorocyclotriphosphazene is 5% of the total mass of the electrolyte.

[0041] Example 2

[0042] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the three is 50:20:30); the electrolyte lithium salt is lithium bis(trifluoromethyl sulfonyl) imide and lithium difluorophosphate, wherein the concentration of lithium bis(trifluoromethyl sulfonyl) imide in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.05 mol / L; and the additive is tetraethenesilane, citraconic anhydride and ethoxy pentafluoro cyclo-triphosphazene, wherein the amount of tetraethenesilane is 1% of the total mass of the electrolyte, the amount of citraconic anhydride is 1% of the total mass of the electrolyte, and the amount of ethoxy pentafluoro cyclo-triphosphazene is 5% of the total mass of the electrolyte.

[0043] Embodiment 3

[0044] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the three is 50:20:30); the electrolyte lithium salt is lithium bis(trifluoromethyl sulfonyl) imide and lithium difluorophosphate, wherein the concentration of lithium bis(trifluoromethyl sulfonyl) imide in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.05 mol / L; and the additive is tetraethenesilane, citraconic anhydride and ethoxy pentafluoro cyclo-triphosphazene, wherein the amount of tetraethenesilane is 1% of the total mass of the electrolyte, the amount of citraconic anhydride is 1% of the total mass of the electrolyte, and the amount of ethoxy pentafluoro cyclo-triphosphazene is 5% of the total mass of the electrolyte.

[0045] Embodiment 4

[0046] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the three is 50:20:30); the electrolyte lithium salt is lithium bis(trifluoromethyl sulfonyl) imide and lithium difluorophosphate, wherein the concentration of lithium bis(trifluoromethyl sulfonyl) imide in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.05 mol / L; and the additive is tetraethenesilane, citraconic anhydride and ethoxy pentafluoro cyclo-triphosphazene, wherein the amount of tetraethenesilane is 1% of the total mass of the electrolyte, the amount of citraconic anhydride is 1% of the total mass of the electrolyte, and the amount of ethoxy pentafluoro cyclo-triphosphazene is 5% of the total mass of the electrolyte.

[0047] Embodiment 5

[0048] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of ethylene carbonate, propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the four is 8:42:15:35); the electrolyte lithium salt is lithium trifluoromethanesulfonate and lithium difluorophosphate, wherein the concentration of lithium trifluoromethanesulfonate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; the additive is tetra (trimethylsilyl) silane, 2,3-pyridinedioic anhydride and hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene, wherein the amount of tetra (trimethylsilyl) silane is 1% of the total mass of the electrolyte, the amount of 2,3-pyridinedioic anhydride is 0.5% of the total mass of the electrolyte, and the amount of hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene is 5% of the total mass of the electrolyte.

[0049] Embodiment 6

[0050] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of ethylene carbonate, propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the four is 8:42:15:35); the electrolyte lithium salt is lithium trifluoromethanesulfonate and lithium difluorophosphate, wherein the concentration of lithium trifluoromethanesulfonate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; the additive is tetra (trimethylsilyl) silane, 2,3-pyridinedioic anhydride and hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene, wherein the amount of tetra (trimethylsilyl) silane is 1% of the total mass of the electrolyte, the amount of 2,3-pyridinedioic anhydride is 0.5% of the total mass of the electrolyte, and the amount of hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene is 5% of the total mass of the electrolyte.

[0051] Embodiment 7

[0052] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of ethylene carbonate, propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the four is 8:42:15:35); the electrolyte lithium salt is lithium trifluoromethanesulfonate and lithium difluorophosphate, wherein the concentration of lithium trifluoromethanesulfonate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; the additive is tetra (trimethylsilyl) silane, 2,3-pyridinedioic anhydride and hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene, wherein the amount of tetra (trimethylsilyl) silane is 1% of the total mass of the electrolyte, the amount of 2,3-pyridinedioic anhydride is 0.5% of the total mass of the electrolyte, and the amount of hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene is 5% of the total mass of the electrolyte.

[0053] Embodiment 8

[0054] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of vinyl carbonate, propylene carbonate, ethylene glycol dimethyl ether and sulfolane (the mass ratio of the four is 8:42:15:35); the electrolyte lithium salt is lithium bisfluorosulfonylimide and lithium difluorophosphate, wherein the concentration of lithium bisfluorosulfonylimide in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; and the additive is tetra (trimethylsilyl) silane, 2,3-pyridine dianhydride and hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene, wherein the amount of tetra (trimethylsilyl) silane is 1% of the total mass of the electrolyte, the amount of 2,3-pyridine dianhydride is 1% of the total mass of the electrolyte, and the amount of hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene is 10% of the total mass of the electrolyte.

[0055] Embodiment 9

[0056] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (the mass ratio of the three is 50:20:30); the electrolyte lithium salt is lithium bis (trifluoromethyl sulfonyl) imide and lithium difluorophosphate, wherein the concentration of lithium bis (trifluoromethyl sulfonyl) imide in the electrolyte is 1.1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; and the additive is tetra (trimethylsilyl) silane, citraconic anhydride and ethoxy pentafluoro cyclotriphosphazene, wherein the amount of tetra (trimethylsilyl) silane is 1% of the total mass of the electrolyte, the amount of citraconic anhydride is 1.5% of the total mass of the electrolyte, and the amount of ethoxy pentafluoro cyclotriphosphazene is 10% of the total mass of the electrolyte.

[0057] Embodiment 10

[0058] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of vinyl carbonate, propylene carbonate, ethylene glycol dimethyl ether and sulfolane (the mass ratio of the four is 8:32:15:45); the electrolyte lithium salt is lithium tetrafluoroborate and lithium difluorophosphate, wherein the concentration of lithium tetrafluoroborate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; and the additive is tetra (trimethylsilyl) silane, 2,3-pyridine dianhydride and hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene, wherein the amount of tetra (trimethylsilyl) silane is 1% of the total mass of the electrolyte, the amount of 2,3-pyridine dianhydride is 0.5% of the total mass of the electrolyte, and the amount of hexakis (2,2,2-trifluoroethoxy) cyclotriphosphazene is 5% of the total mass of the electrolyte.

[0059] Embodiment 11

[0060] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the three is 30:20:50); the electrolyte lithium salt is lithium tetrafluoroborate and lithium difluorophosphate, wherein the concentration of lithium tetrafluoroborate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; and the additive is difluorodiphenylsilane, phthalic anhydride and ethoxy pentafluorocyclotriphosphazene, wherein the amount of difluorodiphenylsilane is 2% of the total mass of the electrolyte, the amount of phthalic anhydride is 0.5% of the total mass of the electrolyte, and the amount of ethoxy pentafluorocyclotriphosphazene is 5% of the total mass of the electrolyte.

[0061] Example 12

[0062] The embodiment provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the three is 30:20:50); the electrolyte lithium salt is lithium tetrafluoroborate and lithium difluorophosphate, wherein the concentration of lithium tetrafluoroborate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.1 mol / L; and the additive is difluorodiphenylsilane, phthalic anhydride and ethoxy pentafluorocyclotriphosphazene, wherein the amount of difluorodiphenylsilane is 2% of the total mass of the electrolyte, the amount of phthalic anhydride is 0.5% of the total mass of the electrolyte, and the amount of ethoxy pentafluorocyclotriphosphazene is 5% of the total mass of the electrolyte.

[0063] Comparative Example 1

[0064] The comparative example provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent and an electrolyte lithium salt, and no other additive is added. The organic solvent is a mixture of propylene carbonate and ethylene glycol dimethyl ether (mass ratio of the two is 30:70); and the electrolyte lithium salt is lithium tetrafluoroborate, and the concentration of lithium tetrafluoroborate in the electrolyte is 1 mol / L.

[0065] Comparative Example 2

[0066] The comparative example provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent and an electrolyte lithium salt, and no other additive is added. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of the three is 20:30:50); and the electrolyte lithium salt is lithium trifluoromethylsulfonate, and the concentration of lithium trifluoromethylsulfonate in the electrolyte is 1 mol / L.

[0067] Comparative Example 3

[0068] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of organic solvent and electrolyte lithium salt without adding other additives. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 40:20:40); the electrolyte lithium salt is lithium bis(trifluoromethylsulfonyl)imide, and the concentration of the electrolyte lithium salt in the electrolyte is 0.8 mol / L.

[0069] Comparative example 4

[0070] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of organic solvent and electrolyte lithium salt without adding other additives. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 40:20:40); the electrolyte lithium salt is lithium bis(trifluoromethylsulfonyl)imide, and the concentration of the electrolyte lithium salt in the electrolyte is 0.8 mol / L.

[0071] Comparative example 5

[0072] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of organic solvent and electrolyte lithium salt without adding other additives. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 40:20:40); the electrolyte lithium salt is lithium bis(trifluoromethylsulfonyl)imide, and the concentration of the electrolyte lithium salt in the electrolyte is 0.8 mol / L.

[0073] Comparative example 6

[0074] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of organic solvent and electrolyte lithium salt without adding other additives. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 40:20:40); the electrolyte lithium salt is lithium bis(trifluoromethylsulfonyl)imide, and the concentration of the electrolyte lithium salt in the electrolyte is 0.8 mol / L.

[0075] Comparative example 7

[0076] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of organic solvent and electrolyte lithium salt without adding other additives. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 40:20:40); the electrolyte lithium salt is lithium bis(trifluoromethylsulfonyl)imide, and the concentration of the electrolyte lithium salt in the electrolyte is 0.8 mol / L.

[0077] Comparative example 8

[0078] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and 1,3-dioxolane (mass ratio of 30:20:50); the electrolyte lithium salt is lithium trifluoromethanesulfonate, and the concentration of the lithium trifluoromethanesulfonate in the electrolyte is 1 mol / L; the additive is citraconic anhydride, and the amount of the citraconic anhydride is 1% of the total mass of the electrolyte.

[0079] Comparative example 9

[0080] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and 1,3-dioxolane (mass ratio of 30:20:50); the electrolyte lithium salt is lithium trifluoromethanesulfonate, and the concentration of the lithium trifluoromethanesulfonate in the electrolyte is 1 mol / L; the additive is citraconic anhydride, and the amount of the citraconic anhydride is 1% of the total mass of the electrolyte.

[0081] Comparative example 10

[0082] The comparative example 1 provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and 1,3-dioxolane (mass ratio of 30:20:50); the electrolyte lithium salt is lithium trifluoromethanesulfonate, and the concentration of the lithium trifluoromethanesulfonate in the electrolyte is 1 mol / L; the additive is citraconic anhydride, and the amount of the citraconic anhydride is 1% of the total mass of the electrolyte.

[0083] Comparative example 11

[0084] The comparative example provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 30:20:50); the electrolyte lithium salt is lithium tetrafluoroborate and lithium difluorophosphate, wherein the concentration of lithium tetrafluoroborate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.05 mol / L; the additive is difluorodiphenylsilane, phthalic anhydride and ethoxy pentafluoro cyclo-triphosphazene, wherein the amount of difluorodiphenylsilane is 1% of the total mass of the electrolyte, the amount of phthalic anhydride is 0.5% of the total mass of the electrolyte, and the amount of ethoxy pentafluoro cyclo-triphosphazene is 1% of the total mass of the electrolyte.

[0085] Comparative Example 12

[0086] The comparative example provides a lithium-carbon fluoride battery electrolyte for tire pressure, which is composed of an organic solvent, an electrolyte lithium salt and an additive. The organic solvent is a mixture of propylene carbonate, ethylene glycol dimethyl ether and sulfolane (mass ratio of 30:20:50); the electrolyte lithium salt is lithium tetrafluoroborate and lithium difluorophosphate, wherein the concentration of lithium tetrafluoroborate in the electrolyte is 1 mol / L, and the concentration of lithium difluorophosphate in the electrolyte is 0.05 mol / L; the additive is difluorodiphenylsilane, phthalic anhydride and ethoxy pentafluoro cyclo-triphosphazene, wherein the amount of difluorodiphenylsilane is 1% of the total mass of the electrolyte, the amount of phthalic anhydride is 0.5% of the total mass of the electrolyte, and the amount of ethoxy pentafluoro cyclo-triphosphazene is 1% of the total mass of the electrolyte.

[0087] Performance test:

[0088] The discharge performance of the battery is tested by using a Shenzhen Xinwei battery tester (5V 10mA).

[0089] Twelve comparative examples and twelve examples are prepared into electrolytes according to the formula, and are injected into BR2450 type button lithium-carbon fluoride batteries, and are respectively tested by 85℃ high-temperature discharge, 125℃ high-temperature storage, large-current pulse discharge and-40℃ low-temperature discharge.

[0090] The 85℃ discharge test condition is: 80℃, 24H storage, constant current 20mA, cut-off voltage 2.0V.

[0091] The 125℃ high-temperature storage thickness test method is: 125℃ oven storage for 100h, and observation of battery leakage and explosion.

[0092] The test method of large-current pulse discharge is: 3A constant current discharge for 3s, 27s storage, and cycle until the voltage stops at 1.8v.

[0093] The test method of low-temperature discharge is as follows: 24 h storage at-40℃, constant current 20 mA, cut-off voltage 2.0 V.

[0094] The test results of all the comparative examples and examples are shown in Table 1.

[0095] Table 1

[0096]

[0097]

[0098] Table 1 shows that by optimizing the organic solvent, using the double lithium salt (which must contain lithium difluorophosphate), simultaneously using the silane additive (difluorodiphenylsilane, tetraethylenylsilane or tetrakis(trimethylsilyl)silane), the acid anhydride additive (phthalic anhydride, citraconic anhydride, propyl phosphonic anhydride or 2,3-pyridinedicarboxylic anhydride) and the phosphazene additive (ethoxy pentafluorocyclotriphosphazene or hexa(2,2,2-trifluoroethoxy)cyclotriphosphazene), and controlling the compounding ratio and the amount of the three types of additives, the conductivity of the electrolyte can be improved, a stable SEI film can be formed, the power characteristics of the battery can be improved, and the battery still has good discharge performance at a wide temperature range, which can meet the use requirements of the lithium fluorocarbon battery for tire pressure in special fields. At the same time, the compounding use of the three types of additives greatly inhibits the risk of fire and explosion of the battery, and greatly improves the safety of the battery under long-time high-temperature storage.

[0099] The above has described the present application in detail, which is intended to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A lithium fluoride carbon battery electrolyte, comprising an organic solvent, an electrolyte salt, and additives, characterized in that, The electrolyte is a mixture of lithium tetrafluoroborate, lithium di(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium trifluoromethanesulfonate, and lithium difluorophosphate. The additives include silane additives, acid anhydride additives, and phosphazene additives, and the mass ratio of the silane additives, acid anhydride additives, and phosphazene additives is (1~5):(0.5~1):(3~10). The silane additive is one or more of difluorodiphenylsilane, tetraethylenesilane, and tetra(trimethylsilyl)silane; The acid anhydride additives are one or more of phthalic anhydride, citrate anhydride, propylphosphohydrin, and 2,3-pyridinedi anhydride; The phosphazene additives are ethoxypentafluorocyclotriphosphazene and / or hexa(2,2,2-trifluoroethoxy)cyclotriphosphazene. The amount of the silane additive is 0.1% to 5% of the total mass of the lithium fluoride carbon battery electrolyte; The amount of the acid anhydride additive is 0.1% to 3% of the total mass of the lithium fluoride carbon battery electrolyte; The amount of the phosphazene additive is 2% to 20% of the total mass of the lithium fluoride carbon battery electrolyte.

2. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The additives consist of silane additives, acid anhydride additives, and phosphazene additives.

3. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The concentration of the electrolyte salt is 1~2 mol / L.

4. The lithium fluoride carbon battery electrolyte according to claim 1 or 3, characterized in that, The concentration of lithium difluorophosphate is 0.05~0.2 mol / L.

5. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The amount of the silane additive is 0.5% to 5% of the total mass of the lithium fluoride carbon battery electrolyte; The amount of the acid anhydride additive is 0.5% to 1% of the total mass of the lithium fluoride carbon battery electrolyte; The amount of the phosphazene additive is 2% to 10% of the total mass of the lithium fluoride carbon battery electrolyte.

6. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The organic solvents include ester solvents, ether solvents, and sulfone solvents. The ester solvent is one or more of the following: ethylene carbonate, propylene carbonate, γ-butyrolactone, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl butyrate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate. The ether solvent is one or more of the following: ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, 1,4-dioxane, 1,3-dioxane, and tetrahydrofuran; The sulfone solvent is one or more of vinyl sulfone, dimethyl sulfoxide, and sulfolane.

7. The lithium fluoride carbon battery electrolyte according to claim 6, characterized in that, The mass ratio of the ester solvent, ether solvent and sulfone solvent is (1~5):1:(1~3).

8. A lithium fluoride carbon battery, wherein the positive electrode material is fluoride carbon and the negative electrode material is metallic lithium, characterized in that, The electrolyte of the lithium fluoride carbon battery is the lithium fluoride carbon battery electrolyte according to any one of claims 1 to 7.

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