Study On The Influence Of Electrolyte Additives On The Low Temperature Performance Of Lead-acid Batteries

Lead-acid batteries are one of the most important secondary batteries and are widely used in various industries.Low temperature will cause the discharge capacity of lead-acid batteries to decrease,and it will be difficult to charge,which will affect the service life of lead-acid batteries.Poor low-temperature performance limits the application of lead-acid batteries in winter,especially in northern regions.Adding additives to lead-acid batteries is a common and effective method to improve their performance.At present,there are few studies on improving the low-temperature performance and additives of lead-acid batteries.Exploring the low-temperature performance of lead-acid batteries and finding additives that can effectively improve the low-temperature performance of lead-acid batteries have important application values.In this thesis,six substances including bismuth oxide,stannous sulfate,sodium sulfate,disodium EDTA,L-cysteine,and sodium citrate were added to the sulfuric acid solution as electrolyte additives for lead-acid batteries.Perform low-temperature discharge capacity test,low-temperature cycling capability test,and low-temperature charge acceptance test on the battery,explore the effects of these six additives on the low-temperature performance of the battery,and find suitable electrolyte additives;use XRD,SEM,CV to explore mechanism of cysteine affecting the low-temperature performance of lead-acid batteries.This paper also studies the effect of silica content on the low-temperature performance of colloidal batteries and compares the difference in low-temperature performance between colloidal batteries and batteries using sulfuric acid solutions.The main research results are as follows:1?The low-temperature discharge capacity of lead-acid batteries is lower than normal temperature.At 0 °C,-10 °C,and-20 °C,the 0.5C discharge capacity of lead-acid batteries is about 80%,70%,and 50% of the discharge capacity at room temperature;Bismuth oxide,stannous sulfate,cysteine,and sodium citrate can improve the low-temperature discharge capacity of lead-acid batteries.Among them,cysteine and sodium citrate increase the low-temperature discharge capacity of the battery more;as the temperature decreases,the effect of bismuth oxide on the low-temperature discharge capacity of the battery gradually weakens.Bismuth oxide,stannous sulfate,cysteine,and sodium citrate as electrolyte additives can improve the low-temperature cycle discharge capacity of batteries.When batteries with stannous sulfate and sodium citrate are used as additives,the cycle stability of the battery is not good.Cyclic discharge capacity decays rapidly;bismuth oxide-added batteries have better cycle stability.As the ambient temperature decreases,the increase in low-temperature cycle discharge capacity of the battery is reduced with the addition of bismuth oxide.Adding bismuth oxide and cysteine can increase the low-temperature charging current of the battery and improve the low-temperature charge acceptance of the battery.The battery with the addition of bismuth oxide has a larger charging current and a better low-temperature charge acceptance.2?Lead-acid batteries with L-cysteine added to the electrolyte have the best low-temperature performance XRD,SEM,CV have found that cysteine can change the appearance of lead sulfate crystals on the negative electrode surface It can reduce the crystallinity of lead sulfate crystals,make the shape of lead sulfate crystals more irregular,and inhibit the generation of large lead sulfate crystals.These lead sulfate crystals are more easily reduced to lead during the charging process,which improves the battery's charge acceptance.The reversibility with the redox reaction suppresses the sulfation of the negative electrode,enables more lead to participate in the discharge reaction,and improves the low temperature performance of the battery.3?The content of silica will affect the physical properties of the colloidal electrolyte.With the increase of the content of silica,the gel time of the colloidal electrolyte is shortened,the viscosity is increased,and the stability is increased;the discharge capacity of the colloidal battery is lower than that of the battery using sulfuric acid solution And with the increase of silicon dioxide content,the discharge capacity of colloidal batteries is getting lower and lower;colloidal electrolytes with silicon dioxide content of 4% wt and 6% wt can slow down the decline of battery discharge capacity due to lower ambient temperature.It can also improve the low-temperature cycle discharge capacity,cycle stability,and low-temperature charge acceptance of lead-acid batteries.