Ultralow-temperature explosion-proof lithium iron phosphate battery

Abstract

The invention provides an ultralow-temperature explosion-proof lithium iron phosphate battery which comprises a lithium iron phosphate battery monomer, wherein the lithium iron phosphate battery monomer comprises a positive plate, a negative plate, a diaphragm plate and an electrolyte; the positive plate comprises a positive current collector and more than two modified nanoscale lithium iron phosphate positive active materials with + 2 valence elements; the negative plate comprises a negative current collector and a negative active material, the negative active material comprises conductive carbon and a binder, and the particle size D50 of the conductive carbon is 2-9 [mu] m; the electrolyte is a low-temperature electrolyte, the solute is lithium hexafluorophosphate (LiPF6) and an electrolyte additive, and the crystallization temperature critical point of the electrolyte is about-55 DEG C; the diaphragm plate is positioned between the positive plate and the negative plate; the positiveplate, the diaphragm plate, the negative plate and the electrolyte are hot-pressed and packaged through an aluminum-plastic film. Based on the characteristic nanoscale lithium iron phosphate cathodeactive material electrode material and the ultralow-temperature crystallization electrolyte, direct charging and discharging at the temperature of-55 DEG C to-45 DEG C can be realized without a preheating plate, and ultralow-temperature safe use of the battery is met.

Description

technical field [0001] The invention belongs to the field of battery technology. Specifically relates to an ultra-low temperature explosion-proof lithium iron phosphate battery. Background technique [0002] When lithium-ion batteries are used in military equipment, the most important thing is safety. Due to various factors such as impact, short circuit, and ultra-low temperature in the use environment of the equipment, the anti-knock problem of lithium-ion batteries has become the core issue used in equipment; and At present, many batteries use aluminum-plastic film cell technology. Under the influence of the external environment, deformation will occur when the internal pressure increases. When the pressure is greater than 0.5-1.0㎏ / c㎡, deformation and self-leakage will occur, so the internal pressure is always maintained. Only when the pressure is less than 0.5kg can the existence of pressure explosiveness be eliminated. [0003] At present, the charging protection circu...

AI Technical Summary

Problems solved by technology

[0006] At present, the commonly used lithium iron phosphate battery has the problems of low discharge capacity in ultra-low temperature environment, unable to charge, and rapid capacity decay under ultra-high temperature conditions, which affects its normal use in some special fields (such as space, military, smart grid, and power vehicles). , hindering the rapid development of lithium iron phosphate batteries

Moreover, when communication devices such as mobile phones and automobiles using lithium-ion batteries operate in winter or in a cold environment, if the power supply cannot provide sufficient energy output, these devices cannot operate normally.

The low-temperature charge and discharge performance of lithium iron phosphate batteries still has a technical bottleneck, which affects the application under low temperature conditions

Since the electrical conductivity of the lithium iron phosphate battery itself is lower than that of other positive electrode materials, although the electrical conductivity of the material is improved after the implementation of carbon coating and nano-refined particles, the charge and discharge performance of the battery drops sharply when the temperature drops to -20°C. Big limit on battery usage

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