Lithium battery pack consists of five major systems

Lithium-ion battery packs include the following main components: Lithium-ion cells – The basic electrochemical unit providing electrical storage capacity. Multiple cells are combined to achieve the desired voltage and capacity. Battery Management System (BMS) – The “brain” monitoring cell conditions and controlling safety and performance.

Lithium-ion battery cells come in three main formats: cylindrical, prismatic, and pouch cells. Cylindrical battery cells were the first lithium-ion batteries to achieve mass production. They're made by winding the cathode, anode, and separator in a specific order into a cylinder shape and then housing it in a metal casing.

The voltage of a lithium-ion battery cell is typically around 3.7 volts. The voltage of a lithium-ion cell is a crucial parameter as it influences the overall voltage of a battery pack when multiple cells are connected in series.

A lithium-ion battery module is a group of interconnected battery cells that work together to provide a higher level of voltage and capacity. Modules are designed to facilitate efficient cooling and thermal management, ensuring that the temperature within the battery remains within safe operating limits.

In the case of lithium-ion cells, lithium ions move between the positive (cathode) and negative (anode) electrodes during charge and discharge cycles. Different combinations of materials result in batteries with varying energy density, voltage, cycle life, and safety features. The voltage of a lithium-ion battery cell is typically around 3.7 volts.

There are also significant differences in cost structure. In the total battery pack cost, battery cells account for the largest portion at around 50%, with cathode materials being the main cost component of the battery cells. At the battery module level, costs increase due to structural components and connectors.