A lithium battery

Abstract

A lithium battery is disclosed. The lithium battery comprises a cathode sheet, an anode sheet, a separating membrane, an electrolyte and an outer package. The cathode sheet comprises a cathode current collector and a cathode material with which the cathode current collector is coated, and the anode sheet comprises an anode current collector and an anode material with which the anode current collector is coated. The cathode material comprises a cathode active compound, a cathode conductive agent and a cathode adhesive. The anode material comprises an anode active compound, an anode conductive agent, a thickening agent and an anode adhesive. The lithium battery has a high specific capacity and high stability. The energy density of a battery core assembled by the cathode having a high specific capacity and the lithium titanate anode in match can be 90 Wh / kg, and is obviously higher than the energy density of lithium titanate batteries at present. High-temperature resistance of the electrolyte is improved. A gas generating amount is reduced. Cyclic properties are good. The service lifetime is prolonged. High and low temperature properties and flame retardance of the electrolyte are improved. Wettability and pouring performance of the electrolyte are improved through adding 1,3-propanesultone.

Description

technical field [0001] The invention relates to a battery, in particular to a lithium battery. Background technique [0002] At present, the anode materials of commercialized lithium-ion batteries are basically graphite-like carbon materials. Carbon materials have the advantages of high thermal stability, good electrical conductivity, fast intercalation and extraction of lithium ions, and high reversibility. Compared with lithium titanate, lithium titanate has obvious advantages: 1) It is a near-zero-volume deintercalation lithium insertion material, which does not change its structure during charging and discharging, and has good cycle performance; 2) It has a good charging and discharging platform; 3 ) The theoretical specific capacity is 175mAh / g, the actual specific capacity can reach 160mAh / g, and it is concentrated in the platform area; 4) It does not react with the electrolyte; 5) The raw material is cheap and easy to prepare; 6) It has the characteristics of fast ch...

AI Technical Summary

Problems solved by technology

Carbon materials have the advantages of high thermal stability, good electrical conductivity, fast intercalation and extraction of lithium ions, and high reversibility. Compared with lithium titanate, lithium titanate has obvious advantages: 1) It is a near-zero-volume deintercalation lithium insertion material, which does not change its structure during charging and discharging, and has good cycle performance; 2) It has a good charging and discharging platform; 3 ) The theoretical specific capacity is 175mAh / g, the actual specific capacity can reach 160mAh / g, and it is concentrated in the platform area; 4) It does not react with the electrolyte; 5) The raw material is cheap and easy to prepare; 6) It has the characteristics of fast charging and discharging (an order of magnitude higher than the carbon diffusion system); it has the possibility of long life and high safety, so whether it is in the field of plug-in hybrid electric vehicles or large-scale energy storage, its application prospects are unanimously optimistic. Become a research hotspot around the world

[0003] However, lithium titanate batteries have not entered the market at this stage. One of the main reasons is that the energy density of lithium-ion batteries assembled by lithium titanate and common cathode materials lithium iron phosphate, lithium manganate, and ternary materials is low. 50Wh / kg–75Wh / kg, the main reason is that the lithium ion insertion and extraction potential platform of the lithium titanate negative electrode is relatively high, which is much higher than the lithium ion insertion and extraction potential platform of the graphite negative electrode, resulting in the output voltage of the full battery being generally only 1.7V -2.5V or so, far lower than the 3.2-4.2V of graphite negative lithium-ion batteries

In addition, the gram capacity of the above-mentioned positive electrode materials lithium iron phosphate, lithium manganate, and ternary materials is generally lower than 160mAh / g, so the problems of low battery capacity, low voltage platform, and low energy density are unresolved.

[0004] In addition, it has been found in practical applications that batteries with lithium titanate as the negative electrode tend to swell at high temperatures. This phenomenon is especially obvious for flexible packaging batteries, and the high and low temperature performance is poor.