Many people are confused with Anode, Cathode, Positive and Nagative.

Let's check the definitions firstly.

Anode is the electrode where oxidation reaction occurs.

Cathode is the electrode where reduction reaction occurs.

Positive is the electrode which potential is higher than another. Its symbol is "+".

Negative is the electrode which potential is lower than another. Its symbol is "-".

Voltage is the potential difference between positive and negative electrodes.

We can find the positive and negative electrodes are not changeable whenever electrochemical cell or electrolytic cell.

For the primary batteries and rechargeable batteries when discharging, positive is cathode and negative is anode.

For the electrolytic cell and rechargeable batteries when charged, positive is anode and negative is cathode.

Batteries are the energy sources for many devices. There are various of types, shapes, chemical systems and costs of batteries in the market.

How to choose the right battery for your application?

We need consider these factions to choose the battery, rechargeable or not, operation mode (voltage and current), life span, operation environment (humidity and temperature)， battery box size and shape, cost, and so on.

Rechargeable batteries are used for the applications where the energy will be consumed fast or recharged easily, such as cellular phones, laptops, vehicles, etc. The rechargeable batteries can be recharged hundreds of times, but with high self-discharge rate. Lithium ion, Lead Acid, Nickel-based batteries are rechargeable. Primary batteries are used where light drain or recharged inconveniently, such as remote controls, smoke alarms, smart meters, etc. The primary batteries will be used only one time, but with very long shelf life. Zinc-Carbon, alkaline and Lithium metal batteries are primary.

The different chemical system os batteries with different nominal voltage. Lithium ion batteries with 3.7V or 3.2V, Lithium metal batteries with 3.6V, 3V or 1.5V, Lead Acid batteries with 2V, Zinc-Carbon and alkaline batteries with 1.5V, Nickel-based(Ni-MH/Ni-Cd) batteries with 1.2V. If higher voltage is required, you can pack it in series.

The battery shapes include cylindrical, prismatic, pouch, button/coin, pin, etc. Usually, cylindrical and button batteries with standard size, such as AA, AAA, C, D, 2032, 18650, and prismatic and pouch batteries with customized size.

The different chemical systems of batteries with different energy and power density. For the same chemical battery, larger energy or power can be got by batteries packed in parallel.

Please feel free to contact us once any question to choose suitable batteries.