What is lithium?

Lithium is a chemical element (a metal) from which batteries can be made. Lithium is the lightest metal from which batteries can be made. There are different types of lithium batteries:

  • The lithium-ion battery
  • The LiFePO4 battery
  • The Lithium battery
  • Lithium titanate

These batteries are sometimes mixed up but all have different properties. Within these four categories, there are many different types, all with different technologies and properties. They all use lithium as an element to store energy. Lithium is an element with a very high energy density. This makes lithium batteries a lot less heavy than any other metal from which a battery can be made. The different types of lithium batteries differ in energy density, lifespan, charging, currents and price.

The lithium-ion (Li-ion) battery

An Ion is an electrically charged molecule or atom. The Lithium-Ion is characterised by a high energy density. This makes the battery relatively light for how much energy it stores. For this reason, it is widely used in electronic devices such as laptops and in electric cars, for example. Most Rebelcell batteries are also Li-ion batteries. Li-ion batteries can be discharged a lot deeper than lead batteries (more than 95%) but not 100%. So Li-ion batteries usually have a Battery Management System that prevents the battery from being discharged too deeply. The Li-ion battery “family” includes:

  • LMO / LMA: smartphones, laptops and cameras
  • NCA: Tesla electric drives
  • NMC: Electric drives from BMW, Mercedes, Jaguar, Kia, Hyundai and batteries from Rebelcell and Torqeedo.

Advantages of lithium-ion battery:

  • Higher energy density: more power in less space
  • Better performance: deep discharge, constant energy output
  • Easier, faster and intermediate charging
  • Longer service life
  • Improved ease of use

LiFePO4 battery

The LiFePO4 battery has lithium iron phosphate as cathode. This battery is slightly heavier than the regular Li-ion battery but can deliver a high pulse current. The Rebelcell start is a LiFePO4 battery. This battery is only 12Ah but can deliver as much as 470A for 5s (at normal temperature).

Which is better Lithium-ion or LiFePO4 battery

It’s hard to say. They both have different properties, so it depends on the application which technology is best to choose. See the table below for the technical differences:

Voltage per cel 3.2V 3.65V
Energy storage (Watthour per kilogram) 90-120Wh/kg 150-220Wh/kg
Charge (C-Rate) 1C, 3,65V Peak 1C, 4.2V Peak
Discharge (C-Rate) 20C continous 2C continous
Cycles 1500-2000 1000-1500
Self Discharge Hoog Laag
Prestations when cold Weak (-60%) Fair (-20%)

Given the advantage in size and weight, Rebelcell batteries for fishfinders and electric motors use NMC technology. As the Rebelcell start requires a high peak voltage to be delivered, LifePO4 technology was chosen.

The lithium battery

Lithium batteries, unlike other lithium batteries, are not rechargeable. The advantage of Lithium batteries is that they last a very long time. As a result, they are widely used in watches or remote controls, for example.

Lithium titanate

The main advantage of the Lithium titanate battery or battery is that it can be recharged much faster than a Li-ion battery. The disadvantage is that it has a lower energy density and is therefore a lot heavier.