🔋 Battery Cell Formats
Lithium-ion (Li-ion) batteries are manufactured in various cell formats, each designed to optimize energy density, mechanical stability, and thermal performance for specific applications. The three most common formats are Cylindrical, Prismatic, and Pouch cells, as illustrated below:
Figure: Common Lithium-ion Battery Cell Formats
📊 Cell Format Comparison Table
| Cell Type | Structure | Advantages | Disadvantages | Applications |
|---|---|---|---|---|
| Cylindrical | Metal casing, rolled electrodes | Durable, good thermal stability | Lower energy density | Laptops, Tesla EVs |
| Prismatic | Rigid rectangular housing | Space-efficient, compact | Higher cost, thermal gradients | EVs, Power Tools |
| Pouch | Flexible polymer shell | Lightweight, high energy density | Less mechanical stability, swelling risk | Smartphones, EVs |
🔵 Cylindrical Cells
- Structure: Rolled layers of anode, cathode, and separator enclosed in a metal casing (e.g., 18650 and 21700 formats).
- Advantages:
- Highly durable and mechanically stable.
- Good thermal management with even heat distribution.
- Cost-effective and widely available.
- Disadvantages:
- Lower energy density.
- Inefficient space utilization due to cylindrical shape.
- Applications:
- Electric Vehicles (Tesla)
- Laptops, power tools, medical devices
🟩 Prismatic Cells
- Structure: Rectangular aluminum or steel casing with stacked or wound electrode layers.
- Advantages:
- Higher energy density.
- Modular and compact packaging.
- Disadvantages:
- Higher production cost.
- Potential thermal gradients requiring active cooling.
- Applications:
- EVs (BMW, Volkswagen, Nissan)
- Energy storage systems
🟨 Pouch Cells
- Structure: Thin flexible polymer laminate enclosure, lightweight and compact.
- Advantages:
- Highest energy density among formats.
- Lightweight and space-efficient.
- Disadvantages:
- Requires external mechanical support.
- Risk of swelling over time.
- Applications:
- Smartphones, tablets, laptops
- EVs (Chevrolet Bolt, Hyundai Kona EV)
🧾 Summary
- Cylindrical: Rugged and cost-effective; used in tools and Tesla EVs.
- Prismatic: Compact and efficient for automotive use, though costlier.
- Pouch: Highest energy density, ideal for lightweight applications but needs reinforcement.