Join us for Part 4 of our Battery Management System (BMS) series! Expanding on our past data platform articles, here we’re exploring how Acculon’s advanced data platform plays a pivotal role in accelerating the development of our proprietary BMS by providing real-time data analytics & predictive insights.
Contact: Betsy Barry
Developing a Battery Management System (BMS) requires the precise calibration of various system components to ensure performance and safety. While Acculon designs its BMS to be adaptable for different low-voltage battery systems, certain parts of the BMS must be fine-tuned to accommodate certain cells and components, depending on the specific application’s needs and requirements. This calibration is a complex process that involves extensive testing and analysis. Acculon’s data platform plays a crucial role in streamlining this process, enabling rapid iteration and optimization of the BMS throughout the development cycle.
The Need for Calibration in BMS Development
Before diving into how the data platform accelerates the process, it’s important to understand the areas that require calibration and why they matter. Let’s explore a few examples of some parameters that are part of the calibration process.
1. Cell Parameters
What needs calibration:
- Internal resistance of cells at various states of charge (SOCs) and temperatures.
- Cell capacity at different temperatures and C-rates (charge/discharge rates).
- Aging properties over time and under different environmental conditions.
Why it matters: These parameters are critical for estimating the battery’s SOC, State of Health (SOH), and calculating current/power limits. Inaccurate estimates can lead to inefficient energy usage or safety risks.
How it’s calibrated: This involves running an extensive testing campaign on the specific battery cells intended for use. Performance and aging tests are conducted, and data is gathered to extract the necessary parameters for the BMS to accurately monitor and manage the battery.
2. Shunt Calibration
What needs calibration:
- The resistance on the shunt at different temperatures.
Why it matters: This resistance is used to calculate the current flowing through the battery, which is crucial for SOC estimation and ensuring the battery stays within safe operational limits.
How it’s calibrated: Tests are conducted at various temperatures and current levels, using a highly calibrated current shunt for accuracy. The data gathered ensures the BMS accurately measures and manages current.
Acculon’s data platform is a critical enabler for efficient BMS development. It simplifies & speeds up the process of calibrating cell parameters, thermal characteristics, & hardware components, providing engineers with the tools they need to quickly iterate & improve their BMS designs.
3. Thermal Characteristics
What needs calibration:
- Cell heat capacity under various conditions.
- Thermal resistance between the top cell temperature and baseplate temperature measurements.
Why it matters: Not every cell in the pack has a direct temperature measurement. Therefore, proper battery temperature estimation is essential for ensuring the battery does not operate outside its allowable temperature window, thus keeping the battery safe and extending its lifespan.
How it’s calibrated: This requires thermal and electrical cycling of a fully assembled battery pack. Direct temperature measurements are taken with multiple thermocouples to gather detailed thermal data, which the BMS uses to accurately estimate battery temperatures.
4. Full System Verification
What needs calibration:
- Connection resistances and heat generation at various C-rates.
- BMS current draw.
- Current and voltage readings.
Why it matters: These factors affect both battery temperature and SOC estimation. For example, any electrical connection inside the pack, including the wire bonds, can be a source of heat generation which needs to be accounted for where direct temperature measurements are not available.,, The BMS gets its power from the battery and while the short-term current draw is low, the capacity drain on the battery can add up over long periods of operation, which ultimately needs to be considered for SOC estimation. The pack utilizes multiple current and voltage readings for both functional and safety-critical redundancy. Therefore, in the event of a failure of one measurement, the relationship between these paired measurements must be well understood if remedial actions are to be taken with confidence.
How it’s calibrated: Special test fixtures are used to measure wire bond resistance, for example, while BMS current draw is measured under various conditions (full load, standby, and sleep). The redundant current and voltage measurements are compared to each other and with the data from highly calibrated lab sensors to ensure accuracy.
The Role of Acculon’s Data Platform in Accelerating BMS Calibration
Given the complexity of BMS calibration, having an efficient and scalable data platform can dramatically accelerate the development process. Acculon’s data platform solves key challenges that often slow down BMS development.
1. Seamless Data Access
One of the biggest bottlenecks in data analysis is accessing the collected data efficiently. Traditional data acquisition systems often store data locally, requiring complex auxiliary processes to transfer it to more powerful systems for processing. Acculon’s data platform addresses this by providing a browser-based upload tool that enables lab technicians to easily and securely upload collected data to the cloud, where it can be accessed instantly.
2. Expandable Computing Capabilities
Battery testing generates large datasets, especially when testing multiple cells, cycles, and environmental conditions. Processing such data requires significant computational power. Acculon’s data platform offers flexible, cloud-based processing environments (e.g., virtual machines or Docker containers hosted on GCP or AWS). These environments can scale to accommodate the size and complexity of the dataset, allowing for rapid data processing and analysis.
3. Integrated Reporting and Analysis
Another common challenge in data processing is the need to generate and update reports as new metrics are calculated. Acculon’s platform seamlessly integrates data processing and reporting, which means as soon as data is processed or new calculations are made, the platform automatically updates the corresponding reports with the latest results. This eliminates the need for manual report updates, saving time and reducing the chance of human error.
4. Efficient and Secure Data Organization
With multiple tests, parameters, and datasets involved in BMS calibration, organizing the data is crucial. Acculon’s platform makes it easy to save, store, access, and protect processed data in the cloud. The structured datasets allow engineers to quickly find the information they need without sifting through disorganized files or drives. Data security is prioritized through controlled access and permissions to individual datasets.
Accelerating the Development Cycle
By providing a streamlined approach to data access, processing, and reporting, Acculon’s data platform accelerates the entire BMS development lifecycle. In a testing environment, the platform can handle the entire process—from lab testing and data collection to processing for calibration and validation testing—in seconds. This rapid turnaround allows engineers to focus more on optimizing the BMS rather than dealing with data management and processing overhead.
Acculon’s data platform is a critical enabler for efficient BMS development. It simplifies and speeds up the process of calibrating cell parameters, thermal characteristics, and hardware components, providing engineers with the tools they need to quickly iterate and improve their BMS designs. The result is a faster, more reliable path to developing robust battery management systems that are tailored to specific applications.
The next post in this series is going to focus on BMS integration, so stay tuned!