Lithium iron phosphate battery (LiFePO4, LFP)

Lithium-iron-phosphate battery (LiFePO ₄ , LFP) is a type of electric battery that is a type of lithium-ion battery that uses LiFePO ₄ as the cathode.

LiFePO ₄ battery

Specifications

• Energy density: 90–110 W * h / kg (320-390 J / g)
• Volumetric energy density: 220–250 W * h / dm ³ (790 kJ / dm ³ )
• Volume density of a design: 2 kg / dm ³
• The number of charge / discharge cycles to a loss of 20% capacity: 2000-7000 ^[1]
• Shelf life: up to 15 years ^[1]
• Self-discharge at room temperature: 3-5% per month
• Voltage
  • maximum in the element: 3.65 V (fully charged)
  • Midpoint: 3.3 V
  • minimum: 2 V (fully discharged)
  • working: 3.0-3.3 V
  • minimum operating voltage (discharge): 2.8 V
• Specific power:> 6.6 W / g (when discharging current 60C)

Story

For the first time, LiFePO ₄ was discovered in 1996 by Professor John Goudenough of the University of Texas as a cathode for a lithium-ion battery. Notable for this material was that in comparison with traditional LiCoO ₂ , it has a significantly lower cost, is less toxic and more heat resistant. The main disadvantage was that it had a smaller capacity. Until 2003, this technology practically did not develop until A123 Systems took over it. The history of A123 Systems began in the laboratory of Professor Jiang Ye-Ming from the Massachusetts Institute of Technology (MIT) at the end of 2000. At that time, Jiang was working on creating a battery based on self-reproducing the structure of a colloidal solution under certain conditions. However, on this front of the work, serious difficulties arose and when in 2003 the research reached an impasse, the Jiang team took up the study of lithium-iron-phosphate batteries . Such world corporations as Motorola, Qualcomm and Sequoia Capital became investors in the established company.

Advantages and disadvantages

LiFePO4 battery comes from lithium-ion, however, has a number of significant differences:

• LiFePO4 provides a longer service life than other lithium-ion approaches;
• Like nickel batteries (unlike other lithium-ion batteries), LiFePO ₄ batteries have a very constant discharge voltage. The output voltage remains close to 3.2 V during discharge, until the battery is fully depleted. And this can greatly simplify or even eliminate the need for voltage regulation in circuits.
• Due to a constant voltage of 3.2 V at the output, four batteries can be placed in series to obtain a rated output voltage of 12.8 V. This approximates the rated voltage of a six-cell lead-acid battery. And, along with the good safety performance of LFP batteries, this makes them a good potential replacement for lead-acid batteries in many applications, such as automotive and solar applications.
• The use of phosphates avoids the cost of cobalt and environmental problems, in particular, concerns about cobalt released into the environment if disposed of incorrectly.
• LiFePO ₄ has a higher peak current or power than LiCoO ₂ .
• The energy density (energy / volume) of a new LFP battery is about 14% lower than that of new lithium-ion batteries.
• LiFePO ₄ cells have a lower discharge rate than lead-acid or lithium-ion batteries. Since the discharge rate is determined as a percentage of the battery capacity, a higher discharge rate can be achieved in more capacious batteries (more ampere hours). However, LiFePO ₄ cells with a high discharge current (which have a higher discharge rate than lead-acid batteries or LiCoO _{2 of} the same capacity) can be used.
• Due to a slower decrease in energy density, after some time of operation, LiFePO ₄ cells already have a higher energy density than LiCoO ₂ and lithium-ion cells.
• LiFePO ₄ cells lose their capacity more slowly than lithium-ion batteries, such as LiCoO ₂ , cobalt or manganese, LiMn ₂ O ₄ , spinel, lithium-polymer or lithium-ion batteries.
• One of the important advantages compared with other types of lithium-ion batteries is thermal and chemical stability, which significantly increases the safety of the battery.

Manufacturers

At the moment, most of the factories for the production of lithium-iron-phosphate batteries are concentrated in China. However, in Russia, in Novosibirsk, an enterprise is being created with the joint participation of Rosnano OJSC, LIOTECH LLC for the production of these batteries ^{[2] [3] [4] [5]} .

• Coslight Technology International Group Limited
• Benning
• Liotech
• A123Systems.
• BYD Company ^[6] .
• Shandong Hipower New Energy Group.
• China Sun Group.
• Lithium Technology Corporation.
• Tenergy.
• Thunder Sky Group.
• Valence Technology.
• K2 Energy.
• FULLRIVER Battery.
• Zhuhai Yintong Energy.
• Optimum Battery

This type of battery is actively used in electric vehicles.