BMS testing in battery pack assembly: why it matters and how to get it right

What is BMS testing and why it’s critical in battery pack manufacturing

A Battery Management System (BMS) is the brain behind every battery pack. It monitors critical parameters like voltage, temperature and current, balances the cells, protects the system from unsafe conditions, and ensures proper communication with external devices. BMS testing in battery assembly ensures that all these functionalities are operating correctly before the battery leaves the production line.

Typical tests include:

• Communication validation (e.g. CAN, LIN protocols)

• Overvoltage and undervoltage protection

• Temperature monitoring

• Charge and discharge cycles

These tests are critical for the safety, reliability, and performance of the final product.

Where BMS testing fits in the battery assembly process

BMS testing is typically integrated towards the end of the battery pack assembly line, after all cells and electronic components have been installed. At this stage, the BMS is connected to the pack and ready to be activated and tested.

Depending on the type of product and production strategy, manufacturers can take different approaches:

In some cases, the BMS is tested as part of an end-of-line (EOL) station, where the entire battery pack undergoes a final round of functional and safety checks. This is common in automotive applications, where full traceability and performance validation are essential before shipping.

In smaller-scale or modular systems (for example, in micromobility or industrial storage) BMS testing may be performed earlier in the process, on individual modules rather than the full pack.

Some manufacturers use standalone BMS test stations, especially during development or pilot phases. Others integrate testing directly into an automated sequence, where the BMS is validated in parallel with other systems like cooling or final sealing.

The choice depends on factors like production volume, product complexity, level of automation, and regulatory requirements.

Key challenges when integrating BMS testing into a production line

Integrating BMS testing in a high-throughput environment involves several challenges: 

Protocol variability

Different customers use different communication standards (CAN, LIN, UART, etc.), and the system must be able to switch and interpret accordingly. 

Electrical and isolation requirements

Proper high-voltage isolation and grounding must be considered for safety and accuracy. 

Cycle time vs. test duration

Functional testing can take longer than standard assembly steps. The line must be designed to handle this without creating bottlenecks. 

MES integration and traceability

BMS test results must be linked to the serial number of each battery pack and stored for quality control and compliance. 

To address these challenges, Mondragon Assembly designs and integrates automated test solutions that adapt to each project’s specifications. From multi-protocol communication to full traceability and safe electrical configurations, our systems are engineered to keep performance and reliability at the core of the process. 

How automation improves BMS testing reliability and efficiency

Automating BMS testing enables capabilities that would be nearly impossible to achieve manually.

For example, in high-density battery packs where access to terminals is limited, automated stations can use programmable fixtures that adapt dynamically to the pack geometry, ensuring precise connections under safe conditions. During testing, the system communicates with the BMS via CAN or LIN protocols and validates response times down to milliseconds,  a level of granularity that’s critical for advanced EV or energy storage applications.

What to look for in BMS testing station provider

If you are a battery pack manufacturer, an integrator in the mobility sector, or a company entering the energy storage market, integrating BMS testing it’s a strategic decision. It will define how reliable, scalable, and compliant your production line is from day one.

The ideal partner must go beyond delivering a machine. Look for someone who:

• Understands battery systems: Including electrochemical behavior, thermal dynamics, and cell variability.

• Masters automation: Capable of designing and seamlessly integrating custom test stations into your line — without disrupting your flow.

• Offers long-term collaboration: With service, upgrades, and flexibility to grow with your production roadmap.

Mondragon Assembly works with companies like yours — whether you’re scaling up a line, launching a new pack, or transitioning from pilot to full production. Our team combines industrial automation know-how with deep battery expertise to help you make every pack count.