What is the difference between lead-acid and lithium batteries?

 

Lead-acid batteries, the chemical power source with a history of more than 160 years, is currently widely used in various fields such as communication, motive power, electricity, energy storage, emergency, etc. It has mature production technology and high reliability.

 

At the same time, due to its low production cost and strong environmental applicability, it plays an important role in all aspects of economic and social development. However, with the development of science and technology, more and more new batteries have been put into the market, and the performance has been continuously optimized and improved, and the scope of use has continued to expand.

 

The most representative is the lithium-ion battery, which has the advantages of high energy density, high discharge voltage, and long cycle life. Its application field has gradually expanded from the initial portable electronic equipment to power, communication, energy storage, military aerospace, etc., and gradually overlaps the fields with lead-acid batteries., showing a clear competitive relationship.

 

For a while, lead-acid batteries will be replaced by lithium batteries, and the outlook is worrisome. Where should lead-acid batteries break out has become a topic of concern to the industry.

 

 

Advantages and disadvantages of lead-acid batteries：

 

Compared with lithium-ion batteries, lead-acid batteries have the disadvantages that :

 • The energy density battery is low.

 • The cycle life is short.

 • Discharge capacity is only half of that of lithium-ion batteries.

 • It may cause heavy metal lead pollution in the process of production and use.

 But it has certain advantages in production cost, maintainability, recycling efficiency and safety performance.

 

Lithium-ion batteries are superior to lead-acid batteries in performance and cost of use, and it is the general trend to replace them. The energy density of lithium-ion batteries can reach 4 times that of lead-acid batteries, the cycle life is also 3-4 times that of lead-acid batteries, the energy conversion efficiency can reach 97%, and it is more environmentally friendly.

 

At the same time, with the improvement of battery manufacturing technology and production scale, the price of lithium-ion batteries has dropped to twice or even less than lead-acid batteries. At present, the cost of lithium-ion batteries is lower than that of lead-acid batteries in terms of the cost of a single cycle. It is a general trend for lithium-ion batteries to replace lead-acid batteries in all application scenarios.

 

Performance parameters	Lead-acid batteries	Lithium battery (lithium iron phosphate)
Specific energy	30-50Wh/kg	100-150Wh/kg
Cycle life	300-500 times	>2000 times
Environmental impact	Lead pollution	No pollution
Cost of production	About 0.165 USD/Ah	About 0.325 USD/Ah
Maintainability	Dealer direct on-site replacement	Need to return to the factory for repair
Recycling efficiency	More than 90 percent	low recycling value
Safety performance	High security	Need PCM/BMS

 

Analysis of application areas：

 

The downstream of lead-acid batteries is mainly used for low-speed vehicles such as electric bicycles, starting power for automobiles, and other portable devices. At present, light power batteries account for 33%, automotive starting batteries account for 45%, and industrial batteries account for 22%.

In the field of light power such as electric bicycles, lithium batteries have begun to be gradually replaced, and 48V mild hybrids have improved the economical efficiency in terms of starting power for automobiles.

 

1.Starter battery field

 

At present, lead-acid batteries are almost invincible in the field of car starting, and lithium-ion batteries still have a long way to go. This mainly depends on the use environment and requirements of the starter battery, and the main reasons are as follows:

 

a) Regarding the cost requirements, the cost of lead-acid batteries is half lower than that of lithium batteries, and the replacement of lithium batteries requires changes to the charging power system, resulting in higher costs;

 

b) Regarding the low temperature and high current performance requirements, the starting battery is required to be able to start the vehicle normally at -40 ℃, while the low temperature and high current performance of the lithium ion battery (lithium iron phosphate) is very poor, and it is difficult to meet the requirements for use in the northwest and northeast regions;

 

c) Regarding safety requirements, the starting battery is generally located near the engine in the engine room, in a high temperature and closed space. At the same time, the lithium ion battery is flammable and explosive after being hit, and will decompose and volatilize toxic gases, which are not conducive to the application of lithium batteries. 

 

Therefore, the starting field, as an inherent field of lead-acid batteries, currently has unparalleled advantages over lithium-ion batteries.

 

2.Motive Power field

 

 

At present, lead-acid batteries have suffered a certain impact in terms of motive power supply, such as electric bicycles and electric forklifts.

 

According to EVTank data, in 2021, the output of lithium-ion electric two-wheelers will be 13.17 million units, with an overall penetration rate of 24.2%, driving the shipment of lithium-ion batteries for electric two-wheelers to 13.1GWh, a year-on-year increase of 21.7%.

 

Sales of lithium battery forklifts : From 2018 to 2020, lithium battery forklifts continued to develop in China with a sales growth rate of 200%, and they also had a sales growth rate of 100% in 2021. From these two fields, we can see the rapid development trend of lithium battery replacing lead acid in the field of power supply.

 

3.Telecommunication base station field

 

 

The battery for telecommunication base station is the field that lead-acid battery being occupied most by lithium battery. In 2016 , lithium batteries only accounted for the majority of batteries used in communication base stations 20 % but since 2018 , in accordance with the government policy orientation, the telecommunication company began to stop purchasing lead-acid batteries, and switched to purchasing lithium batteries.

 

In particular, in recent years with the construction of 5G base stations, the energy consumption of base stations is 3 times higher than the 4G base stations. In addition, the high-density arrangement of batteries and the limited load-bearing of roofs and other locations also require the support of miniaturized, high-energy-density energy storage systems. Therefore, lithium batteries become the first choice for 5G base station backup power.

 

In order to re-emerge in the base station power supply market for lead-acid batteries, it is necessary to adopt lightweight new materials and new technologies while maintaining the existing advantages, focusing on improving the energy density and service life of the battery.