Home >> News
In addition to the serious decline in discharge capacity, lithium batteries cannot be charged at low temperatures. During low-temperature charging, the intercalation of lithium ions on the graphite electrode of the battery and the lithium plating reaction coexist and compete with each other. Diffusion of lithium ions in graphite is suppressed under low temperature conditions, and the conductivity of the electrolyte decreases, which results in a decrease in the intercalation rate and makes the lithium plating reaction easier to occur on the graphite surface. The main reasons for the decrease in the life of lithium-ion batteries when they are used at low temperatures are the increase in internal resistance and the loss of capacity due to the precipitation of lithium ions.
At low temperatures, lithium batteries bring about a decrease in the activity of positive and negative electrode materials and a decrease in the conductivity of the electrolyte. In response to the macro, a series of results such as decreased capacity, increased internal resistance, and reduced discharge efficiency occurred. However, the lithium battery has good high temperature performance: the thermal peak value of the lithium iron phosphate battery can reach 350 ~ 500°C, the operating temperature range is wide, and it can still discharge 100% capacity under high temperature conditions.
During the charge-discharge process of lead-acid batteries, there are electrochemical polarization and concentration polarization. Large-current charge and discharge are mainly affected by concentration polarization. For lead-acid batteries, when the operating temperature drops below 0°C, serious negative polarization will occur during the initial charge of the battery, which will limit the battery's ability to accept charges, which will cause the battery's charge and discharge to decrease significantly as the temperature decreases.
When the ambient temperature drops below 0°C, the internal resistance increases by about 15% for every 10°C decrease in temperature. Because the viscosity of the sulfuric acid solution increases, the resistance of the sulfuric acid solution is increased, and the effect of electrode polarization is aggravated. The battery capacity will be significantly reduced.
Compared with lead-acid batteries, Lithium Iron Phosphate Battery's low temperature performance and high current performance are weaker, which is definitely not good for starting power. The discharge performance of lead-acid batteries can cope with more severe environments, and lithium batteries cannot perform in low temperature areas. In addition to the low temperature, in the summer exposure conditions, the high temperature of 60 to 70 degrees in the engine compartment can easily make lithium electronics scrap. In terms of high-current performance, the instantaneous current of the car at startup is mostly above 200A, and the performance of lithium batteries will rapidly decline at high rates.
At low temperatures, the discharge performance of lithium batteries will suddenly decrease, especially now that it is winter. The colder weather in the north has a significant impact on lithium batteries. This was also verified when chatting with a Tesla owner; and The low-temperature performance of the lead-acid battery is very good. According to data from the Internet, when the voltage is discharged at a rate of 10C in an environment of -10 degrees Celsius, a voltage above 10V can be maintained for more than 90 seconds.
LFP Battery System
So how to improve the low temperature performance of lithium iron phosphate battery? LFP Battery System Supplier will come to tell you.
Factors affecting the low-temperature characteristics of lithium iron phosphate batteries: One is the influence of the positive electrode. The lithium iron phosphate positive electrode has poor electronic conductivity, and it is more prone to polarization and reduce capacity. The second negative electrode, the negative electrode, is mainly low temperature. Charging because it affects safety issues; the third is the electrolyte, which may increase the viscosity at low temperatures and the lithium ion migration resistance will increase; the fourth is the binder, which is now a low temperature for the battery The performance impact is also relatively large. At present, some manufacturers have improved the low-temperature performance of lithium iron phosphate batteries by improving the electrolyte system, improving the formula of the positive electrode, improving the performance of materials, and improving the design of the cell structure, but they have not really met the demand.