Lithium batteries

Lithium (Li-ion) batteries are the technology that is revolutionizing energy storage systems, especially in solar photovoltaic installations, being the ideal alternative to conventional lead batteries.

The two main advantages of lithium batteries in renewable energy systems, especially in systems with solar panels are:

• Maximum efficiency: Unlike lead-acid batteries, where the energy losses suffered during charging and discharging reach 25% to 30%, lithium batteries, the losses from charging and discharging are only 9%, which is up to 21% more energy usable from solar panels or another renewable source of energy.
• Healthy: Lithium batteries do not emit any kind of gas, not even residual, unlike the rest of batteries, even the AGM hermetic give off a little toxic steam. The Li-ion batteries are not, so they are ideal for installations with solar panels in houses.

Information about lithium batteries

The general operating principle is the same as with lead acid batteries, requiring an anode and cathode to perform the electrochemical reaction, except that in li ion batteries the main element is lithium salts, a rare mineral.

The first lithium accumulators began to be commercialized in 1990, but we did not begin to follow up until 1997, but its high price made it unviable for our market. It was in 2005 when we began to be able to propose its use at a commercial level, but it cost 1000€/kwh, nothing to do with the 300€/kwh to which we sell them today.

Features and benefits of lithium batteries:

Another interesting feature of lithium batteries are the discharge cycles, which determines their useful life. We have lithium batteries ranging from 3500 cycles as the Pylontech, to 10,000 cycles as the LG Chem RESU.

When we compare lithium batteries with the equivalent batteries in lead acid, the OPzS, from the point of view of useful energy throughout their life, we see that lithium batteries are not more expensive. €/cycle.

• Lifetime: More than 3500 cycles, up to 10,000 cycles in LG Chem RESU batteries.
• Discharge Depth: Can be discharged up to 90% and still have more discharge cycles than 50% DoD lead acid.
• Self-discharge: The self-discharge in lithium batteries is very low, all batteries self-discharge, but Li-ion batteries self-discharge only 6% per month, while Ni-MH is more than 20% per month.
• Almost no memory effect: Forget about full cycles, use what you need.
• Lightweight: Weigh less, and occupy less space than any other similar technology, Ni-MH, Ni-Cd or leado
• High voltage: Each lithium cell has 3.7 volts, thanks to this we can have high voltage batteries, 100VDC and 400VDC in very small dimensions, making solar photovoltaic installations super efficient systems in terms of savings in the section of wiring and energy losses involved. (Ni-MH or Ni-Cd cells are 1,2V)
• High performance:
• Higher energy density: Li-ion batteries have a much higher amount of energy per unit of weight and volume than the rest.
• LiFePO4: The technology of lithium ferro phosphate 4 is the safest of all, and recommended for homes, although with lower energy density than those used in electric vehicles. Both BYD and LG Chem use this technology..
• Stable voltage: Lithium batteries keep the voltage stable until the end of their useful load, giving voltage stability to the inverters that allow them to work at maximum efficiency.

Combinations of lithium batteries with inverters:

• SolaX Inverters:
  • SolaX Triple Power: (2.5kWh peak)
    • X1-Hybrid 3 and 3-7: Minimum 1 battery
    • X1-Hybrid 5: Minimum 2 batteries
    • X3-Hybrid 5: Minimum 2 batteries
    • X1-Hybrid 6: Minimum 3 batteries
    • X1-Hybrid 8 and 10: Minimum 4 batteries
  • BYD B-Box H: The use of BYD with SolaX voids the warranties, but it works.
    • X1-Hybrid 3 and 3-7: Minimum 2 batteries
    • X1-Hybrid 5: Minimum 4 batteries
    • X3-Hybrid 5: Minimum 4 batteries
    • X1-Hybrid 6: Minimum 5 batteries
    • X1-Hybrid 8 and 10: Minimum 8 batteries
  • Pylontech HV X1 and Force H1:X1-Hybrid 3 and 3-7: Minimum 1 battery
    • X1-Hybrid 5: Minimum 2 batteries
    • X3-Hybrid 5: Minimum 2 batteries
    • X3-Hybrid 6: Minimum 3 batteries
    • X3-Hybrid 8 and 10: Minimum 4 batteries
    • X1-Hybrid 3 and 3,7: Minimum 2 batteries
• Victron Energy Multiplus and Quattro inverters:
  • BYD B-Box Pro: Minimum two B-Box L batteries (Pro)
  • LG Chem RESU: 1 battery, regardless of size.
  • Pylontech 48V: Minimum 1 battery for the 3kw, 2 for the 5kw 8 for the 10kw Quattro and 12 for the 15kW Quattro.
• Ingeteam Sun Storage Inverters:
  • BYD B-Box H: Minimum 3 batteries for Sun Storage 3kw and 5 batteries for Sun Storage 1 Play 6kW
• Inverters Kostal Plenticore and Piko MP Plus:
  • BYD B-Box H: 1 battery, regardless of capacity.
• Voltronic Axpert King and VMIII inverters:
  • Pylontech 48V: US2000B or US3000B models, minimum 2 batteries.

Maintenance and care of lithium batteries:

• A full charge per month is recommended.
• If the batteries are to be stored for a long time, it is advisable to do so at 40% of the charge, never at full charge.
• Heat is one of the greatest enemies of lithium batteries, the ideal temperature is 15 º C, keep out of direct sunlight.
• Lithium batteries have to be charged with specific chargers that allow to charge this technology.

Where to buy lithium batteries:

You can buy the lithium batteries that we distribute in Europe through your local solar installer or through our customers’ online stores.

• Our installers, you can buy through our online catalog
• Our distributors can buy through the Webportal B2B

History of lithium batteries:

If you want more technical information, you can go to our educational section edu.technosun.com