Introduction to Battery Modules

This page will overview the components and their purpose when building a battery module in a very generalized manner.

What’s a Module?

In simple terms, a module is a collection of individual cells electrically connected together. In layman’s terms, a module is a very simple concept, though in order to create a safe a functional module there are some other required components (as we’ll talk about in the next section).

What goes into a Module?

To create a module, we’ll need the following:

The individual batteries that create a module.

Cells, highlighted in blue, within a module (note this module is not complete and is missing some components)

Plates that hold the cell in place and restrict movement. They contain openings to allow for electrical connections to be made between the cells on the top and bottom sides.

Top and Bottom Plate highlighted in blue (note this module is not complete and is missing some components)

The main current-carrying conductors in the module. They create connections between the cells and usually take the form of nickel strips or metal sheets that are spot-welded to the modules.

Balance taps measure the voltage of the cells within a module. They measure voltage to see how balanced a module is. If a module is not balanced (meaning the cells inside are at different voltages), the cells inside the module are at risk of cell degradation and even an explosion. Keeping tabs on the voltage of the cells in the module is important to flag any potential risks and safety hazards.

The balance taps are typically a wire attached to the busbars (via soldering or crimps) that travel to the AFE board, so the board can measure the voltage and charge the cell accordingly if need be.

AFE - Analog Front End

An AFE board is an ‘Analog Front End board’ that can read various information from the real world such as temperature, voltage, etc.

BMS - Battery Management System

As the name suggests, the BMS board is the ‘Battery Management System board’ that takes information from the AFE inputs and reacts accordingly. For example, if the AFE reads that the voltage in a module is low, the BMS board can charge the cell to balance the module.

Both work together to keep a module healthy, safe and functional.

Reference Materials

All the referenced links below are taken from MSXIV’s battery module design process. There is extensive documentation and research and is highly recommended to sift through it to gain a better understanding of how modules work:

Battery Modules MSXIV

The Battery Module Concept series is a great reference to see all the different components of a module and what the design process for a module can look like (Goes to Rev 7):

https://uwmidsun.atlassian.net/l/cp/0Ex0qPVQ

Though there is not much visual aspect, this page is useful to see the assembly steps for creating a module:

https://uwmidsun.atlassian.net/l/cp/cUufm4wL