Battery BMS’s Hardware Design Challenges

At the moment of rapid development of battery technology, battery management system (BMS) is a key component to ensure the safe and efficient operation of batteries, and its hardware design faces many challenges. Here are some of the main challenges and industry trends in BMS hardware design.

1. Accuracy Challenge

• BMS requires accurate measurement of the battery's voltage, current and temperature parameters to accurately estimate the battery's state of charge (SOC), state of health (SOH) and state of power (SOP). The chemical characteristics of batteries are complex and are affected by various factors such as temperature and aging. Different batteries have different charging and discharging characteristics. For example, lithium iron phosphate batteries (LFP) have low energy density but low cost, long cycle life and stable, while nickel-cobalt-manganese (NMC) lithium batteries have high energy density but high cost.
• Accurate measurement of battery voltage is one of the key challenges, which is affected by factors such as self-discharge and load changes of the battery. Temperature changes will also significantly affect the performance of the battery and the accuracy of measurement. For example, high temperatures will accelerate the aging of the battery and reduce the capacity and performance of the battery.

2. Security Challenges

• One of the core tasks of BMS is to ensure that the battery operates within a safe range and prevent abnormal situations such as overcharge, overdischarge, overcurrent and overtemperature. For example, overcharging will cause the chemical reactions inside the battery to lose balance, produce gas, increase the pressure inside the battery, and even cause dangerous situations such as bulging, fire or explosion; overdischarge may cause irreversible chemical changes in the electrode materials inside the battery, reducing the performance and life of the battery.  
• Thermal management of batteries is also an important safety issue in BMS hardware design. Lithium batteries usually use flammable electrolytes. If the battery is pierced or overcharged, the electrolyte will decompose and release heat, which may cause heat to run out of control. Even if the thermal runaway is not reached, high operating temperatures can accelerate the aging of the battery.

3. Thermal management challenges

• BMS requires accurate measurement of the battery's voltage, current and temperature parameters to accurately estimate the battery's state of charge (SOC), state of health (SOH) and state of power (SOP). The chemical characteristics of batteries are complex and are affected by various factors such as temperature and aging. Different batteries have different charging and discharging characteristics. For example, lithium iron phosphate batteries (LFP) have low energy density but low cost, long cycle life and stable, while nickel-cobalt-manganese (NMC) lithium batteries have high energy density but high cost PDF.  
•  Accurate measurement of battery voltage is one of the key challenges, which is affected by factors such as self-discharge and load changes of the battery. Temperature changes will also significantly affect the performance of the battery and the accuracy of measurement. For example, high temperatures will accelerate the aging of the battery and reduce the capacity and performance of the battery.

4. Cost Challenge

• BMS hardware design needs to strike a balance between cost and performance. High-performance BMSs often require the use of advanced electronic components and complex circuits, which increases the cost of the system. For example, the use of high-precision sensors and analog-to-digital converters can improve measurement accuracy, but also means higher costs.
•  For large-scale battery systems such as electric vehicles and energy storage systems, the cost of BMS accounts for a considerable proportion of the overall system cost, which may hinder its widespread use in some cost-sensitive applications. Therefore, how to reduce costs while ensuring BMS functions and performance is an important challenge facing hardware design.

5. Scalability challenges

• Designing a BMS architecture that can adapt to different battery sizes, chemistry and configurations is a challenge. With the continuous advancement of battery technology, BMS must be able to adapt to future needs flexibly without large-scale modifications or replacements.
• For example, in electric vehicles, the capacity and configuration of the battery pack may vary depending on the model, and the BMS needs to be able to be easily expanded and adjusted to meet the needs of different models. At the same time, for the secondary utilization of batteries retired from electric vehicles, BMS is also required to have good scalability to meet the performance and safety needs of these aged batteries.

6. Reliability Challenge

• BMS hardware must operate stably under various operating conditions and environments to ensure the reliability and safety of the battery system. However, hardware components may fail or performance degraded due to factors such as electromagnetic interference, vibration, and humidity.  
• For example, during an electric vehicle, the BMS is subject to electromagnetic interference caused by engines and other electronic devices, which may affect the normal communication and data transmission of the BMS. In addition, the battery pack will be subjected to vibration and shock during the vehicle's driving, which may also cause damage to the hardware components of the BMS.

7. Certification compliance challenges

• BMS design must comply with various safety and performance standards, such as ISO 26262 for automotive applications and UL 1973 for fixed batteries. Meeting these certification requirements increases design and development complexity.  
• The certification requirements for BMS vary in different application fields and regions. BMS designers need to fully consider these requirements at every stage of design, from component selection to quality assurance testing and manufacturing preparation to ensure that the product can pass the certification and be put on the market successfully.

8. Communication Challenge

• In large battery systems, monitoring and control electronics are often distributed over multiple printed circuit board components rather than a single centralized BMS computer. Therefore, critical measurement data, safety data and battery health data must be continuously synchronized between multiple microcontroller nodes. Communication failures between any nodes can paralyze the BMS, preventing the correct evaluation of the battery cell voltage and triggering a protection response when an out-of-range condition occurs. 
• For example, in electric vehicles, efficient and reliable communication is required between the BMS and other systems such as on-board chargers, inverters, etc. to achieve precise management and control of the battery. Communication failures can lead to poor battery management, affecting vehicle performance and safety.

9. Future trends

• Integrated Internet of Things (IoT): Integrate BMS with the Internet of Things to enable remote monitoring and control and improve operational efficiency. Through real-time data transmission and analysis, BMS can identify potential battery problems in advance and warn them to ensure the stable operation of the system.  
• Solid-state battery technology: Solid-state batteries have attracted much attention due to their high energy density and good safety, but their characteristics require accurate management and control by BMS. BMS needs to be optimized for the characteristics of solid-state batteries to fully utilize their advantages and meet new challenges.  
• Secondary utilization application: The use of retired electric vehicle batteries in secondary utilization scenarios such as energy storage systems puts higher requirements for BMS. BMS requires managing aging batteries, accurately assessing their performance and health status, and ensuring safety and efficiency.