According to foreign media reports, in the past, most residential solar energy users who deployed battery energy storage systems used lead-acid batteries, especially batteries completely disconnected from the grid. However, in the past few years, this situation has begun to change as more and more residential energy storage systems use lithium batteries. So, which is more suitable for energy storage systems, lithium-ion batteries or lead-acid batteries? The following is an overview of the pros and cons of both.
Since the 1970s, lead-acid batteries have been used as backup power sources for residential solar power facilities. Although they are similar to traditional car batteries, batteries used in residential energy storage systems are called deep cycle batteries because they discharge and charge more frequently than most car batteries.
Traditionally, lead-acid batteries have a lower cost than lithium-ion batteries, making them more attractive to residential users. However, their working life is much shorter than that of lithium-ion batteries.
Comparison of cycle life between lead-acid batteries and lithium-ion batteries in fixed energy storage systems
The working life of lead-acid batteries is lower than that of lithium-ion batteries. Although some lead-acid batteries can charge and discharge up to 1000 times, lithium-ion batteries can charge and discharge between 1000 and 4000 times.
The service life of most lead-acid batteries is approximately 5 years and there is a corresponding warranty period. Therefore, residential users will have to replace lead-acid batteries multiple times during the overall service life of solar power generation facilities.
The energy storage efficiency of lead-acid batteries is lower than that of other energy storage technologies such as lithium-ion batteries. Due to their low efficiency, they cannot charge or discharge quickly like lithium battery energy storage systems.
The discharge capacity of lead-acid batteries is relatively low, which means that consuming too much energy can quickly deteriorate their ability to store energy. A study by the National Renewable Energy Laboratory (NREL) in the United States found that releasing 50% of energy in lead-acid batteries can enable them to complete 1800 charge and discharge cycles before the energy storage capacity significantly decreases. If discharged to 80% of its capacity, it can only withstand 600 charges and discharges, and then its capacity will significantly decrease.
Due to the relatively low energy storage efficiency of lead-acid batteries and their inability to fully discharge, lead-acid batteries require more energy storage capacity and space than lithium-ion batteries. Lead acid batteries are also much heavier than lithium-ion batteries. Placing lead-acid batteries requires a more sturdy bracket and more space than lithium-ion battery packs.
