Series and Parallel Cell Configuration
Series and parallel cell configuration describes how battery cells are electrically grouped to reach the required pack voltage, ampere-hour capacity, energy, and current capability.
Series connections
In a series chain, the positive terminal of one cell or parallel group connects to the negative terminal of the next. Their voltages add, while the same current passes through every series position. The number before s in pack notation is the count of series groups.
Parallel connections
Cells in parallel have their positive terminals connected together and their negative terminals connected together. The group retains the voltage of one cell, while its ampere-hour capacities add. Parallel cells can also share current, increasing current capability when cell matching, interconnections, temperature, and operating limits allow it.
Reading the notation
A 108s4p configuration has 108 groups in series, with four cells connected in parallel in each group. It therefore contains 108 × 4 = 432 physical cells. Nominal pack voltage depends on the 108 series groups and nominal cell voltage; ampere-hour capacity depends on the four parallel cells and their individual capacity.
The arrangement does not define battery chemistry or cell format. The Battery Management System (BMS) monitors and protects the resulting electrical groups. For formulas, module layouts, and pack examples, see Battery Pack & Configuration.