SLA battery or LFP battery for home power storage system?
In the past, the vast majority of household solar energy storage systems used lead-acid batteries, but in recent years, this situation began to change significantly, more and more household energy storage systems began to use lithium-ion batteries. Today, let's discuss which lithium-ion battery or lead-acid battery is more suitable for energy storage system?
Application of lead-acid battery
Since the 1970s, lead-acid batteries have been used in household solar power systems as energy storage batteries. It is similar to the traditional car battery, but the charge and discharge frequency is higher than the car. Because the cost of lead-acid battery is lower than that of lithium-ion battery, family users are more inclined to choose lead-acid battery.
▲ comparison of cycle life of lead-acid battery and lithium-ion battery in fixed energy storage system
The highest cycle number of lead-acid battery is about 1000, while that of lithium-ion battery is mostly between 1000-4000. Therefore, in the high frequency charge discharge cycle of solar energy storage system, users will have to replace the lead-acid battery frequently.
Lead-acid battery also has the problem of low efficiency of discharge and charge, which will consume extra energy in the use process, and can not be charged and discharged as fast as lithium battery system. Therefore, under the same conditions, lead-acid batteries will need more capacity and space, that is, more volume and weight.
Lead is also a toxic heavy metal, even if it is recyclable, a little mishandling will cause pollution.
Application of lithium-ion battery
In recent years, lithium-ion batteries have developed rapidly and become the first choice of many devices. Mobile power, mobile phone, notebook, car, etc. More and more home solar energy storage systems use lithium-ion batteries. However, lithium-ion batteries also have some limitations, first of all, the cost is in the first place.
The initial cost of Li-ion battery is higher than that of lead-acid battery. Tesla's Powerwall energy storage system will cost $5900 or $6600 in the United States in 2018, including supporting hardware. This is a 14kwh battery system, which can provide up to 7KW of power under peak demand. Its cost does not include installation cost.
With the improvement and optimization of lithium battery industry chain, the cost of lithium-ion battery is decreasing. According to the relevant research data in the report of November 2017, the installation cost of the lead-acid battery energy storage system supporting household solar energy is US $598 to US $635 per kWh. Installation costs for lithium-ion batteries range from $831 to $1089 per kWh. But the low cost of lead-acid batteries hides some additional costs, such as shorter working life and higher operating costs.
Lithium ion batteries and energy storage
The cost of ion battery and lead-acid battery for household energy storage system is very important. They can be used as an independent energy storage system, and can also be used with residential solar power generation facilities to meet the energy needs of some or all domestic users or businesses.
In terms of working life, lithium-ion batteries are expected to last for 8-10 years, and they can charge and discharge to a higher level without significantly reducing capacity. The lithium-ion battery used in the home energy storage system is not light, but compared with the lead-acid battery of the same specification, its volume and weight are reduced by about 30%; it can be charged faster under higher voltage; and its safety performance is greatly improved. Of course, there are many advantages of lithium-ion battery. In a word, lithium-ion battery has more advantages than lead-acid battery in energy storage applications, and with the decrease of cost, it will be more and more widely used in energy storage system.
