A solar photovoltaic module consists of a number of interconnected solar cells packaged into a single, long-lasting, stable unit. A key purpose of encapsulating a set of electrically connected solar cells is to protect the interconnecting wires between them from the often harsh environment.

The most common solar panels have 60 solar cells or 72 solar cells with three bypass diodes. The 60-cell assembly was originally intended for ease of handling in residential applications, while the heavier 72-cell assembly is intended for use in larger public facilities with cranes and hydraulic lifts. However, it is entirely possible to use a 72 battery module in a residential installation as long as the rest of the system is designed to handle the large size.
The module life and warranty period of bulk silicon PV modules exceeds 20 years, which shows that encapsulated PV modules are very robust. A typical warranty will guarantee that the components will produce 90% of their rated output for the first 10 years and 80% of their rated output for 25 years.