What is the specific function of the battery?

- Power Quality Lithium-ion batteries are very versatile and are getting bigger, so they are getting more and more functions. Here are some of their features:
Reversible - Dispatch and store energy in batches (sounds trivial, but this is very useful for the grid as most of its assets can only be generated and not stored)
Fast - dispatches and stores power in seconds and milliseconds (making it ideal for emergency services)
Efficient – ​​returns nearly all the energy you store in it (90-95% round-trip efficiency higher than any other competing technology(1))
Flexible - Match power supply and demand on timescales ranging from milliseconds to seconds to minutes to hours (covers most standard grid needs)
Affordable - become cheap and large enough to be deployed in "scheduled" grid operations (i.e. not just "reactive" ancillary services)
Integrating intermittent renewable energy sources into smart grids presents challenges due to the inconsistent nature of energy sources. While solar energy can provide a clean alternative to fossil fuels, the energy produced is difficult to store and utilize during off-peak hours, including cloud cover and at night. Difficulties with load balancing, backup power, grid regulation and line efficiency have created a need for enhanced energy storage systems. The ability to store energy during periods of peak demand and have it ready to return to the grid has inspired the development of lead-acid and lithium-ion batteries to meet the growing demand for energy storage. Just as smaller, longer-lasting lithium batteries became the standard energy storage format used in laptops and cell phones,
Energy storage system format
Solar integrators are adopting a number of different battery technologies, including: lead-acid, lithium-ion, supercapacitors, sodium-sulfur, vanadium redox, flywheels, compressed air, fuel cells, and pumped hydro. With so many options, system designers and integrators need to consider the following:
• Installation, installation, maintenance and mobility issues that affect weight
• Footprint/Location - reduce bulk where space is important
• Modularity/Scalability/Mobility - Ease of system expansion and relocation
• Cycle Life - Evaluate length of life and capacity, eg high C rate
• Service/Maintenance - life expectancy at specified operating temperature
• Charge time - will vary for different battery chemistries
• Capacity loss at high discharge rates - evaluation and comparison