Button cells, also called coin batteries, may be tiny in size, but they power a surprisingly large range of everyday devices. From watches and car keys to medical devices and small electronics, these compact energy sources quietly support modern life. Although they often look similar from the outside, button cells come in different chemistries, voltages, and performance characteristics. Understanding these differences helps users choose batteries more wisely and use them more safely.
What Are Button Cells?
Button cells are small, round, flat batteries designed to fit into compact devices where space is limited. Their “coin-like” shape gives them their common name. Most button batteries are primary batteries, meaning they are intended for single use and cannot be recharged. However, rechargeable button cells do exist for certain applications.
They are typically named with short alphanumeric codes, such as CR2032, LR44, SR626SW, and so on. Each code contains useful information about battery chemistry, size, and sometimes specific application type.
How Do Button Cells Work?
Like all batteries, button cells generate electricity through electrochemical reactions. Inside the cell, a chemical reaction between the anode (negative electrode) and the cathode (positive electrode) produces electrons. When the battery is installed in a device and a circuit is completed, electrons flow through the external circuit, providing power.
The electrolyte inside the battery allows ions to move, balancing the reaction. The specific chemical materials used determine the battery’s voltage, capacity, discharge characteristics, and stability.
Common Types of Button Cells
Different button cells are designed for different performance needs. Below are the most widely used types.
1. Alkaline Button Cells
Typical Code: LR44, LR41, LR1130 etc.
Nominal Voltage: About 1.5V
Features:
Widely available and affordable
Suitable for low to medium power devices
Capacity decreases relatively faster compared with silver oxide batteries
Voltage may drop gradually during use
Common Uses: Toys, LED gadgets, simple electronic devices, calculators
Alkaline button cells are often chosen because of their low cost and decent performance for general household applications.
2. Silver Oxide Button Cells
Typical Code: SR626SW, SR44, SR521, etc.
Nominal Voltage: About 1.55V
Features:
More stable voltage output than alkaline cells
Higher energy density
Better performance in precision and long-term applications
Slightly more expensive
Common Uses: Watches, hearing aids, precision instruments, medical measuring equipment
Because of their stable voltage and longer lifespan, silver oxide batteries are widely trusted in devices requiring reliable and consistent power.
3. Lithium Button Cells
Typical Code: CR2032, CR2016, CR2450, CR1220, etc.
Nominal Voltage: Typically 3.0V
Features:
Higher voltage and longer shelf life
Excellent energy density
Performs well across a wide temperature range
Low self-discharge rate
Common Uses: Remote controls, car key fobs, fitness trackers, blood glucose meters, calculators, backup memory power
Lithium button cells are among the most popular choices today because they combine high capacity and reliability with compact size.
4. Zinc-Air Button Cells
Typical Code: PR41, PR44, etc.
Nominal Voltage: About 1.4V
Features:
Uses oxygen from the air as part of the reaction
Provides high energy capacity relative to size
Begins to discharge once the air holes are opened
Short shelf life after activation
Common Uses: Hearing aids and certain medical devices
Zinc-air batteries are especially valued in hearing aids due to their high energy density and lightweight structure.
How to Read Button Cell Codes
Although model numbers may look confusing, they usually follow standard logic.
For example:
CR2032
C = Lithium manganese dioxide chemistry
R = Round (cylindrical/button shape)
20 = Diameter 20 mm
32 = Thickness 3.2 mm
LR44
L = Alkaline chemistry
R = Round battery
44 = Size code
Understanding these codes helps users find replacements more accurately.
Performance Characteristics to Consider
When choosing a button cell, it’s not just about size. Other important aspects include:
Voltage stability: Some chemistries hold voltage more consistently.
Capacity: Determines how long the battery lasts.
Temperature tolerance: Important for outdoor or special devices.
Self-discharge rate: Affects shelf life.
Application requirements: Precision devices often require more stable chemistry.
Safety and Usage Tips
Because button cells are small, they require careful handling.
Keep away from children. Button cells can be dangerous if swallowed.
Do not mix new and used batteries. This may cause leakage or damage.
Avoid mixing different types or brands in the same device.
Store in a cool, dry place. Extreme heat may cause leakage.
Dispose properly. Button batteries contain chemicals and should be recycled through proper channels when possible.
Many countries emphasize safe battery recycling to reduce environmental impact.
Final Thoughts
Button cells may look insignificant compared with larger batteries, but they are vital to many essential everyday and professional devices. Whether powering a wristwatch, medical instrument, remote control, or wearable device, these compact batteries combine precise engineering with convenience.
By understanding different types of button cells, how they work, and where each type performs best, users can make better choices, enjoy more reliable device performance, and handle these tiny power sources more responsibly.
