Energy Density
Energy density is a crucial indicator for measuring the energy storage capacity of a battery, determining how much electrical energy a battery can store under the same volume or weight. Lithium batteries are renowned for their high energy density, typically ranging from 120 to 180 Wh/kg, with some high-performance lithium batteries even reaching 460 to 600 Wh/kg, which is 6 to 7 times that of lead-acid batteries. In contrast, lead-acid batteries have a lower energy density, generally between 40 and 70 Wh/kg. This means that under the same weight, lithium batteries can store more electrical energy, providing longer (range, referring to the distance a vehicle can travel on a single charge) capabilities. For example, for a 48V battery system, the weight of a lithium battery pack is often only about half that of a lead-acid battery, but the range can be significantly increased. This makes lithium batteries undoubtedly the better choice for electric vehicles and high-end electronic devices that prioritize lightweight design and long range.
Charging and Discharging Efficiency
Charging and discharging efficiency reflects the energy conversion efficiency of a battery during the charging and discharging processes. Lithium batteries generally have higher charging and discharging efficiency compared to lead-acid batteries. They charge relatively quickly, taking 3 to 6 hours to fully charge, with some high-performance lithium batteries capable of completing the charging process in 1 to 2 hours. On the other hand, lead-acid batteries require a longer charging time, usually 8 to 10 hours or even longer. During the discharging process, lithium batteries can release electrical energy more fully, reducing energy loss, while lead-acid batteries experience significant energy loss during charging and discharging. This limits the application of lead-acid batteries in scenarios that require fast charging and high-efficiency energy conversion, such as the rapid refueling needs of electric vehicles, where lithium batteries can better meet the requirements. 
Service Life
Cycle life refers to the ability of a battery to maintain a certain capacity or performance after a certain number of charge-discharge cycles. Lithium batteries typically have a cycle life of thousands of times, generally over 1000 times under normal use conditions, with high-quality lithium batteries even reaching around 2000 times, and a calendar life of 5 to 10 years. In contrast, the cycle life of lead-acid batteries is relatively short, usually around 300 to 500 times, with a calendar life of 3 to 5 years. The actual service life is also influenced by various factors such as the usage environment and charge-discharge methods, but overall, lithium batteries have a clear advantage in cycle life. For example, in the case of electric vehicles, vehicles using lithium batteries have a lower frequency of battery replacement in long-term use, saving users the cost and time of replacing batteries.
Safety Performance
Safety is an important aspect of battery technology that cannot be overlooked. Lead-acid battery technology is relatively mature, with a stable chemical nature, and generally does not encounter safety issues such as overheating, combustion, or explosion during normal use. In contrast, lithium batteries are prone to thermal runaway and even cause fire or explosion accidents under the influence of adverse conditions such as overcharging, over-discharging, short circuits, or high temperatures. However, with the continuous advancement of technology, the safety of lithium batteries is gradually improving. For example, by adopting advanced Battery Management Systems (BMS), the state of the battery can be monitored in real time, and measures can be taken in a timely manner to prevent abnormal situations such as overcharging and over-discharging. In addition, for application scenarios such as electric vehicles, heat insulation materials and cooling designs can be used to further enhance the thermal safety of lithium batteries. Nevertheless, even so, lead-acid batteries still have certain advantages in terms of safety.
Cost and Price
Cost and price are important factors influencing battery selection. Due to the complex production process of lithium batteries and the use of some expensive materials (such as cobalt and lithium), their manufacturing costs are relatively high. In contrast, the manufacturing costs of lead-acid batteries are relatively low, and their production processes are more mature. Therefore, in terms of product prices, lithium batteries are usually much more expensive than lead-acid batteries. For example, a set of 48V 20Ah lead-acid batteries may cost between 300 and 500 yuan, while the price of the same specification of lithium batteries may range from 1000 to 2000 yuan or even higher. However, in the long run, although the initial purchase cost of lithium batteries is higher, their longer service life and lower replacement frequency make their total cost in long-term use potentially lower. For cost-sensitive users, such as consumers with limited budgets, lead-acid batteries are a more cost-effective choice; while for users with high performance requirements and sufficient budgets, lithium batteries are more attractive.
Environmental Performance
Environmental performance is an important indicator for measuring the sustainability of battery technology. Lead-acid batteries contain harmful substances such as heavy metal lead and sulfuric acid, which, if not handled properly during production, use, and waste disposal, can cause serious pollution to the environment. Therefore, strict environmental protection measures and regulatory mechanisms are required for the recycling and treatment of lead-acid batteries. In contrast, lithium batteries perform better in terms of environmental performance, as they do not contain toxic heavy metals, and the toxicity of their electrolytes is relatively low. However, the recycling and treatment of lithium batteries still face certain challenges. On the one hand, the recycling technology of lithium batteries is not yet perfect, and the recycling cost is high; on the other hand, if the electrolytes in lithium batteries are not handled properly, they can also have an impact on the environment. Currently, the recycling system for lead-acid batteries is relatively complete, and the recycling technology is also more mature, with most of the lead and sulfuric acid being effectively recycled and utilized. In contrast, the recycling of lithium batteries is still in the development stage, and the recycling technology needs to be further improved.
Application Choices in Different Scenarios
Electric Vehicle Field
In the electric vehicle field, there are high requirements for battery energy density, range, and cycle life. The high energy density of lithium batteries can provide electric vehicles with longer ranges, reducing users' range anxiety; the longer cycle life means that the battery does not need to be replaced frequently during the vehicle's service life, lowering the use cost. Therefore, most electric vehicles currently use lithium batteries as their power source. For example, high-end electric vehicle brands such as Tesla have achieved high ranges and good performance by adopting advanced lithium battery technology. However, with the continuous expansion of the electric vehicle market, the demand for lithium batteries is also increasing, which has led to fluctuations in the prices of lithium battery raw materials and supply shortages.
Electric Bicycle Field
Electric bicycles are sensitive to battery weight and cost. Lithium batteries are lightweight, which can reduce the overall weight of electric bicycles, improving vehicle portability and maneuverability; at the same time, although the initial purchase cost of lithium batteries is high, their longer service life and lower maintenance costs make them economically viable in the long run. However, for consumers who are more price-sensitive or users with low usage frequency and low range requirements, lead-acid batteries are a more suitable choice. Lead-acid batteries are inexpensive and can meet basic travel needs.
Energy Storage Field
In the energy storage field, such as home energy storage and grid energy storage, there are high requirements for battery safety, cost, and cycle life. Lead-acid batteries have mature technology, high safety, low cost, and a complete recycling system, so they are widely used in some energy storage projects with high requirements for cost and safety. However, with the continuous development of energy storage technology, the requirements for battery energy density and cycle life are also increasing. Lithium batteries, with their advantages of high energy density and long cycle life, are gradually emerging in some large-scale energy storage projects. For example, some photovoltaic power generation energy storage projects use lithium batteries as energy storage devices to improve energy utilization efficiency and stability.
Conclusion
Lithium batteries and lead-acid batteries each have their own advantages and disadvantages, and the choice of which battery to use depends on specific application scenarios and needs. If energy density, charging and discharging efficiency, and service life are prioritized, and the budget is sufficient, lithium batteries are a better choice, suitable for electronic products and electric vehicles with high range requirements. If cost sensitivity is high, energy density requirements are low, and the usage environment is relatively fixed, lead-acid batteries are more suitable, commonly found in low-speed electric vehicles, emergency lighting equipment, etc. In practical applications, users should comprehensively consider the performance characteristics of batteries based on their own needs and budgets to make reasonable choices. At the same time, with the continuous advancement of technology, battery technology is also constantly developing, and it is expected that more advanced, cost-effective, and environmentally friendly battery products will emerge in the future, bringing more convenience to people's lives and production.
