Size and Charging Analysis of 18650 Lithium Batteries: From Parameters to Safety - A Comprehensive Guide
I. The Mystery of the Size of 18650 Lithium Batteries: What‘s the difference between it and ordinary batteries?
The "18650" in 18650 lithium batteries is actually its size code - a diameter of 18 millimeters and a length of 65 millimeters. The "0" represents a cylindrical design. This size design makes it a "powerful little cannon" for electronic devices. It is thicker and longer than the common 5-cell batteries (AA type, with a diameter of 14 millimeters and a length of 50 millimeters), and has a higher energy density. For example: The capacity of one 18650 lithium battery is usually 2000-3500mAh, while the capacity of a 5-cell battery is mostly between 800-2000mAh, with a significant difference.
II. Unveiling the Charging Method: How Does 18650 Lithium Battery "Recharge"?
Charging 18650 lithium batteries cannot be done randomly with any charger! It requires a dedicated lithium battery charger. This charger can precisely control the voltage (usually 4.2V) and current (adjusted according to the battery capacity, such as 1A or 2A), avoiding overcharging which can cause the battery to expand or even explode. If using a regular nickel-hydrogen battery charger (with an output voltage of around 1.4V), it will not be able to fully charge; using a high-voltage charger (such as the 5V charger used for charging mobile phones) will directly damage the battery. The three essential elements for safe charging: Choose the right charger, do not mix different types of batteries, and keep away from high-temperature environments during charging.
III. Charging Precautions: These pitfalls must not be stepped on!
The charging of 18650 lithium batteries follows the "three don‘ts principle":
Do not mix charging: Do not charge batteries of different brands or capacities together. Otherwise, the charging speeds will be inconsistent, which may lead to overcharging or undercharging.
No overnight charging: The charging time should be controlled within 3 to 5 hours (depending on the battery capacity and charger current). After it is fully charged, remove the charger promptly to avoid prolonged float charging.
No damage: If there are dents or leakage in the battery casing, do not charge it! Such a battery may have an internal short circuit and may catch fire during charging.
Tip: When charging the battery, place it in a fireproof container (such as a ceramic bowl). In case of any problem, it can help minimize the damage.
