Pack small cylindrical battery

Cylindrical batteries are small in size and are very suitable for battery packs with irregular spaces, making full use of the corner space. Cylindrical cells made of ternary materials have an energy density of 210~250Wh/kg. Large-scale standardized batteries make cylindrical battery packs also have the premise of automated production.

Cylindrical battery packs, such as the 18650 battery pack, are designed to fix multiple cylindrical batteries at designated positions to ensure that excessive displacement does not occur under reasonable vibration and shock conditions. The position of the cell is determined by the cell bracket. In extreme cases, the cell bracket may be deformed.

Battery packs are constructed from two or more individual cells or batteries. They come in two basic types: primary and secondary or rechargeable. Primary batteries are disposable, non-rechargeable devices that must be replaced once their energy supply is depleted.

To connect cylindrical cells to a battery pack, spot welding, laser welding, and wire bonding are common interconnection methods. Among these, ultrasonic wire bonding is considered the most favorable due to its flexibility and high connection quality.

Enclosures made from injection molded plastics are most commonly used for battery packs. For these enclosed pack designs, two or more plastic parts are molded and then assembled with the pack and accompanied circuitry. They can be sealed using glue, mechanical fasteners (Screws) or ultrasonic welding.

Hence they are often regarded as a safer cell format. Cylindrical cell sidewall rupture is a significant issue in most module designs as it nearly always results in thermal propagation to neighbouring cells. The layers of the cell are wound in a spiral. Normally these cells have the lower case as -ve terminal and top centre as the +ve terminal.