In the e-bike, e-scooter, and energy-storage industries, two cylindrical lithium-ion cell types appear most frequently: 18650 and 21700.
Many B-side buyers often ask:

“Why do batteries use different cell models? What is the difference between 18650 and 21700?”

This article explains everything clearly—
why these two standards exist, what their structural differences are, how they perform, and how B2B customers should choose.

1. What Do the Model Numbers Mean? (18650 vs 21700)

The cell model name describes the physical dimensions:

21700 cells are larger, with more active material, and therefore offer higher capacity.

2. Key Differences Between 18650 and 21700 (Clear Summary for B2B Clients)

In simple terms:
   21700 = higher capacity, higher output, higher energy density — but also slightly higher cost.
  18650 = stable, cost-effective, widely used for standard battery packs.

3. Why More Manufacturers Are Moving Toward 21700

1) Higher capacity per cell → easier to build high-capacity battery packs

For example, a 48V 20Ah battery pack:

• 18650 cells → 65–70 pcs

• 21700 cells → 40–50 pcs

Fewer cells =
✔ fewer weld points
✔ lower failure rate
✔ higher consistency
✔ longer lifespan

2) Higher energy density → longer range, same battery size

Same battery case volume, but:

• 21700 version can extend riding range by 15–25%.

3) Lower internal resistance → better power output

Very suitable for:

• Mountain e-bikes

• 500W–1500W high-power motors

• Delivery bikes & heavy-duty usage

4. Then Why Do Many Manufacturers Still Use 18650?

This is a common misunderstanding among buyers:
21700 is not always the best choice. It depends on the application.

Advantages of 18650:

✔ Lower cost
✔ Highly mature supply chain
✔ Stable quality
✔ Compatible with mainstream battery cases
(Hailong, Silverfish, Rear Rack, Bottle Type, etc.)

Recommended for buyers who:

• Are price-sensitive

• Sell standard 250W–500W e-bikes

• Need 10Ah–15Ah battery packs

 18650 remains the best value-for-money option.

5. How Should B2B Clients Choose? (The Most Important Section)

1) For long-range or high-end e-bikes → Choose 21700

Best for brands, premium models, and European markets.

Popular configurations: 48V 17.5Ah / 20Ah / 22Ah

2) For cost-efficient, standard models → Choose 18650

Best for wholesalers, e-commerce sellers, entry-level bikes.

Popular configurations: 48V 10Ah–15Ah (Hailong, Silverfish, etc.)

3) For maximum safety & consistency → Choose premium cell brands

Recommended brands: Samsung, LG, Panasonic, BAK, Lishen, EVE.

6. Conclusion: 18650 vs 21700 — Not Which Is Best, but Which Fits Your Product

• For mass-market, cost-sensitive models → choose 18650

• For long-range, high-power, high-end models → choose 21700

• For international markets requiring premium quality → 21700 is the trend