Difference between A grade and B grade cells.

Grade A Cells

Consistency: Capacity, internal resistance, and size strictly match the specifications; batch variation <2%.

Performance: Cycle life 2000-6000 cycles, high capacity retention.

Certifications: Complete UL, CE, and UN38.3 certifications; traceable QR code.

Warranty: Typically 5-10 years.

BMS: JBD, a reputable brand.

Assembly Process: Machine welding for enhanced strength.

Warranty: 3 years.

Grade B Cells

Source: “Defective” products from the production process (capacity deviation, slight size difference) or Grade A downgraded products that have been in stock for more than 3-6 months.

Price: 30-50% cheaper than Grade A.

Performance: Initial capacity may be close to Grade A, but cycle life is 30-40% shorter, and internal resistance is higher.

Appearance: QR codes are often scratched off or covered, making it impossible to trace back to the original manufacturer.

Risks: Large performance fluctuations; bulging and leakage may occur.

BMS: Using unbranded or simplified BMS, lacking balancing function.

Assembly process: small workshop hand-welding, no air tightness testing, prone to leakage, corrosion, and short circuits.

Lifespan is only 60% of Grade A, yet the actual cost per kilowatt-hour is higher.

Warranty: 1 year.

After-sales cost: Grade B batteries may have a failure rate 3-5 times that of Grade A batteries.