NXP Introduces Controller Focused on Ensuring Battery Temperature and Safety Standards
NXP's latest battery cell controller spearheads advancements in monitoring and managing batteries within the diverse range of temperatures and voltages experienced by electric vehicles. This piece delves into the intricacies of EV battery management and sheds light on the capabilities of NXP’s sophisticated battery cell controller.
The automotive sector's shift towards electric vehicles (EVs) brings with it formidable obstacles to overcome, especially in the domain of EV batteries. With escalating intricacies, enlarging scales, and increasing cell numbers, the imperative of managing these power sources without compromising on their performance, longevity, and safety grows ever more challenging.
Electric vehicle batteries. Image used courtesy of Kia
In a recent move, NXP Semiconductors unveiled a cutting-edge battery cell controller integrated circuit (IC) aimed at delivering elevated standards of safety and reliability for automotive battery management systems (BMS). This article intends to explore the complexities surrounding the management of EV batteries and delve deeply into the features and benefits of NXP’s newly launched IC.
The advent of electric vehicles (EVs) has transformed the automotive industry, but it also poses significant challenges in battery management. High-performance EV batteries require precise monitoring and control to ensure their safety, efficiency, and longevity. NXP's innovative battery cell controller IC represents a response to these challenges, providing accurate voltage and temperature monitoring across the various cells within a battery pack. Let's take a closer look at the complexities of managing EV batteries and how NXP's breakthrough technology is designed to tackle these issues.
Challenges in Battery Management
Lithium-ion batteries are the backbone of modern electric vehicles, but efficiently managing and monitoring them is extremely difficult.
For instance, a typical high-voltage lithium-ion battery system is composed of hundreds of cells connected in series. One major challenge lies in ensuring the uniformity and balance of these cells throughout the battery's lifespan, which requires precise state-of-charge estimations under various conditions.
The anatomy of an EV battery. Image used courtesy of ResearchGate
As part of this, battery management is needed to accommodate temperature variations, which can significantly impact battery efficiency and lifespan. Fluctuations can lead to significant variances in the battery's efficiency and lifespan, necessitating a battery management system (BMS) that can accurately monitor and adapt to these changes. In the same vein, there is a need for consistent performance over the years-long lifecycle of these batteries, encompassing thousands of charge-discharge cycles under different environmental conditions.
Moreover, safety remains a paramount concern. The BMS must mitigate risks associated with high-voltage lithium-ion batteries, such as thermal runaway and uneven charging, which can lead to reduced battery life or, in extreme cases, safety hazards.
NXP's Battery Management IC
To address these challenges, NXP developed the MC33774 battery management IC.
The MC33774 is an 18-channel battery cell controller IC designed for monitoring lithium-ion batteries in automotive applications. To this end, the chip supports 4 to 18 cells per device and provides ISO 26262 ASIL D support for cell voltage and temperature measurements. NXP states the device can achieve a lifetime qualification for less than 2 mV of voltage measurement error across the full temperature and cell voltage ranges of -40°C to +125°C and -5 V to 5 V, respectively.
MC33774 addresses major challenges in automotive battery management. Image used courtesy of NXP
One of the most notable features of the chip is the high cell measurement accuracy, down to ±0.8 mV. This level of precision is crucial in maximizing the usable capacity of various cell chemistries, including nickel manganese cobalt and lithium iron phosphate.
The device's ability to deliver accurate cell measurement data across a broad temperature range is pivotal in ensuring performance and longevity, facilitating precise range predictions for EVs.
The controller also features onboard passive cell balancing with up to 200 mA average cell balancing, incorporating diagnostics, automatic odd/even balancing sequence, and timer, voltage, temperature, and PWM-controlled balancing.
Better Battery Management Leads to Better EV Batteries
In the pursuit of better EV performance, the focus is often on battery technology. However, it doesn’t matter how good the battery is without proper battery management. That’s why NXP’s MC33774 is an important development: it enables high levels of reliability and accuracy in automotive battery management across a range of operating conditions. With the new IC, the company hopes EV batteries can be safer and offer longer operating lives.
