How to Identify Whether a Battery Is NMC or LFP Without a Label?

Identifying a lithium battery without a label can be challenging, but you can quickly determine whether it’s an NMC (Ternary Lithium) or LFP (Lithium Iron Phosphate) battery using three key methods: checking the voltage, examining physical characteristics, and testing performance.

1. Check the Voltage – The Most Direct “ID Card”

Nominal Voltage Measurement

• NMC Battery:Nominal voltage is typically 6V-3.7V per cell (fully charged at 4.2V).
• LFP Battery:Nominal voltage is 2V per cell (fully charged at 3.6V-3.65V).

How to test: Use a multimeter to measure the resting voltage of the battery.

• If the cell voltage is around 3.2V, it is most likely an LFP battery.

How to identify a multi-cell battery pack:

• A 48V battery packcould be composed of either:
  • 13-14 NMC cells in series(13 × 3.7V = 48.1V)
  • 15 LFP cells in series(15 × 3.2V = 48V)

2. Examine Physical Characteristics – Weight, Colour & Structure

1. Weight Comparison

• LFP batteriesare heavier than NMC batteries of the same capacity.
• For example, a 50Ah LFP cellis about 30% heavier than a comparable NMC cell.
• Tip:Pick up the battery—if it feels significantly heavier for its size, it is likely an LFP battery.

2. Outer Casing & Appearance

• LFP Batteries:
  • Typically have a dark grey casing.
  • Some manufacturers print “LFP”on the casing.
  • Prismatic cellsare common in energy storage applications.
• NMC Batteries:
  • Generally have a lighter grey, silver, or white
  • Cylindrical cells (18650, 21700)are widely used in consumer electronics.
  • Pouch cellsare common in high-end EVs.

Note: Colour may vary by manufacturer, so always use additional methods for verification.

3. Test Performance – Charging, Discharge & Temperature Resistance

1. Charging Speed & High-Temperature Resistance

• NMC Batteries:
  • Charge faster(support quick charging).
  • More prone to overheatingin hot weather.
• LFP Batteries:
  • Charge slower, but are more heat-resistant.
  • Can withstand temperatures over 800°Cwithout thermal runaway, making them ideal for high-temperature environments.

Experimental method (use with caution):

• Charge both battery types under the same currentin a controlled environment.
• If the battery heats up significantly, it is likely an NMC battery.

2. Cycle Life Comparison

• LFP batteriestypically last over 2,000 cycles.
• NMC batterieshave a shorter lifespan, around 800-1,200 cycles.
• If the battery has been used for many years and still retains a high capacity, it is likely an LFP battery.

4. How to Rule Out Other Battery Types?

Lead-Acid Batteries:

• Extremely heavy(3x the weight of lithium batteries).
• Nominal voltage is 2V per cell.
• Often housed in plastic casings, prone to aging.

Lithium Titanate (LTO) Batteries:

Nominal voltage of 2.4V per cell.

Very expensive, used in special vehicles or extreme environments.

Nickel-Metal Hydride (NiMH) Batteries:

• Nominal voltage 2V per cell.
• Common in AA and AAA rechargeable batteries.

Safety Warnings!

• Do not disassemble batteries violently—puncturing or short-circuiting can cause fire or explosions.
• If unsure, consult a professional or send the battery for testing.
• Never mix different types of batteries—this may cause overcharging, over-discharging, and severe safety risks.

Summary: How to Identify an Unlabeled Battery?

Use the “Voltage, Appearance, and Performance” method to verify battery type.
For electric vehicle users:

• NMC batteriesare best for higher range.
• LFP batteriesare ideal for durability and safety.

By following these guidelines, you can quickly and safely identify whether a battery is NMC or LFP, even without a label!