Strict adherence to safety standards is necessary when developing electrified applications to ensure reliability and a user-friendly experience. After all, no one wants to encounter a thermal runaway event that could cause smoke or even fire while driving an electric vehicle (EV) or operating mobile devices on a jet at 30000 feet. For product designers of electric vehicle batteries and energy storage systems, this is why very precise and reliable sensors are used to ensure safe operation without affecting performance.

Lithium ion (Li ion) batteries are highly favored for their high energy density and efficiency, which are crucial for electric vehicles and a range of other electronic applications. However, as pointed out by the National Fire Protection Association, "when a battery is damaged or improperly used, charged, or stored, it increases the likelihood of overheating, fire, or even explosion

Considering that there are millions of electric vehicles on the world's roads and billions of mobile devices powered by lithium-ion batteries in use, although thermal runaway incidents are relatively rare, they are not insignificant - according to the Federal Aviation Administration (FAA), there are about two such incidents on US flights per week. With the development of more and more electrification applications, the number of such accidents is bound to increase, and any one of them may have a negative impact on the sales of suppliers.

In addition, according to the International Energy Agency (IEA), over 90% of the current demand for lithium-ion batteries comes from the energy sector, thanks to higher energy density, longer lifespan, and significantly reduced costs since 2010, surpassing other alternatives in power storage applications. With the efforts of various countries, regions, and enterprises to achieve net zero emissions targets, utility scale battery energy storage systems (BESS) are accelerating their application.

Design safety first electrification applications
The demand for lithium-ion batteries is growing in various industries, so product designers must adopt a safety first approach when using lithium-ion batteries in applications.

When the temperature of the battery rises and generates heat, which may lead to fire or even explosion, a thermal runaway event occurs. These events may be caused by overcharging, physical damage that can affect the internal structure, and short circuits resulting from manufacturing defects.

Lithium ion batteries may experience performance degradation due to excessive discharge, external short circuits, extreme environmental high temperatures, and other factors.

Honeywell Sensing and Productivity Solutions provides current and battery safety sensors that application designers can use to improve safety, efficiency, and performance. These sensors can monitor and manage the current and battery health status. Sensors can be used in battery management systems for electric vehicles and battery energy storage systems, providing early problem detection, precise measurement, and customization functions, and can also be integrated into various other applications.

The CSHV series open-loop current sensor (Figure 1) of the company adopts Hall effect and Honeywell proprietary technology, which has excellent performance and reliability in current detection applications, and can measure direct current (DC) in the range of ± 100 ADC to ± 1500 ADC. This series provides analog voltage output proportional to current, making it easy to integrate into various electric vehicle applications, such as current detection in battery management systems (BMS), battery disconnect units (BDUs), power distribution units (PDUs), fault detection, and isolation.

Figure 1: Honeywell's CSHC series sensors use open-loop Hall effect technology. (Image source: Honeywell)

Honeywell's CSNV series current sensors use closed-loop Hall effect technology to achieve high accuracy and stability over a wide temperature range. This series of sensors is used to measure current in battery management systems, electric vehicles, energy storage systems, and other applications that require high precision and reliability. This series can be used to detect sensor and host system faults, as well as power supply voltages that are out of range and out of range. This series is divided into three models:

The CSNV500 device can measure currents up to ± 500 A with an overall accuracy of less than ± 0.5%
The CSNV700 device (Figure 2) can measure currents up to ± 700 A with an overall accuracy of less than ± 0.5%
CSNV1500 can measure currents up to ± 1500 A with an overall accuracy of less than ± 1%