TI has the answers to the eight challenges of automotive electrification

Across the globe, we need to work together to reimagine the automotive industry and reduce emissions, whether helping automakers offload internal combustion engines or transitioning to all-electric vehicles. Electrification has proven to be the best tool to reduce emissions, but as the voltage in the vehicle increases, as shown in Figure 1, monitoring and maintenance subsystems become even more important.

Figure 1: Roadmap from hybrid to electric vehicles 

It is based on the continuous innovation and development of monitoring and maintenance subsystems that the time to market of hybrid/electric vehicles ( HEV /EV) is accelerating, while maximizing driving time and ensuring passenger safety. However, at the same time, there are still some technical difficulties in monitoring and maintenance in battery management systems and traction inverter systems. The following are the eight most common problems and  TI  's suggestions.

1. How to increase energy density and system efficiency to improve the driving range of hybrid/electric vehicles?

Doubling the power output of the same size can save a lot of money and also help fast charging. This can be achieved by operating the power converter (PFC stage and DCDC in OBC or fast DC charger) at a high switching frequency, reducing the size of the magnetic components, which helps to achieve high power density. For a given application, higher system efficiency can lead to lower losses and smaller heat sink solutions. It also reduces thermal stress on the device and helps to extend the service life. 

2. How can hybrid/electric vehicles provide the same user experience as gasoline vehicles?

The driving experience can be improved by increasing the usable range per charge while reducing charging time. To achieve these goals, advanced battery management systems and efficient power electronics are required on both the vehicle and grid infrastructure (charging station) sides. 

3. How to improve the reliability of HEV/EV battery management system?

The BQ79606A-Q1 is designed to improve reliability through the following features:

• Voltage supervisors, temperature monitors and communication functions meet the Automotive Safety Integrity ASIL-D level.

• An optional daisy-chain ring architecture ensures stack communication even when the communication cable is disconnected (limp-home mode).

• Designed to achieve robust hot-swap performance without the need for an external Zener diode. 

4. How to solve the poor discharge performance of lithium-ion battery packs when used in low temperature environments?

Battery packs for hybrid/electric vehicles operate within a controlled temperature range to optimize charge and discharge performance at low temperatures and to ensure that the battery remains within a safe operating region at high temperatures. To apply appropriate thermal management strategies, accurate voltage and temperature sensing at the cell/battery pack is necessary (as shown in the BQ79606A-Q1). These may need to be preheated during cold-crank conditions and cooled at higher temperatures. 

5. How to monitor the BMS system?

The scalable automotive  HEV /EV 6s to 96s Li-ion battery monitoring demonstrator reference design in a daisy-chain configuration implements the BQ79606A-Q1 to create a highly accurate and reliable system design for 3 to 300 series, 12V to 1.2 kV Li-ion battery packs. The design is scalable between 6 to 96 series battery monitoring circuits and communicates battery voltage and temperature to help meet ASIL-D requirements. 

6. What are the advantages of using silicon carbide (SiC) or gallium nitride (GaN) onboard devices in traction inverters?

New advances in SiC power circuits help designers develop more efficient, lighter and smarter EV powertrains such as traction inverters, onboard chargers and fast DC charging stations. Devices such as the new UCC21710-Q1 and UCC21732-Q1 are  TI's  first isolated gate drivers that integrate insulated gate bipolar transistor (IGBT) and SiC field-effect transistor sensing, improving system reliability and providing fast detection time to prevent overcurrent events while ensuring safe system shutdown.

7. How to prevent the traction inverter from overheating?

The TMP235-Q1 helps traction inverter systems react to temperature fluctuations and apply proper thermal management techniques with low power consumption, small package, and high accuracy. Learn more about temperature monitoring when designing traction inverters in the eBook "Temperature Monitoring and Maintenance." 

8. Why are temperature sensors needed to ensure reliability of traction inverter systems?

Temperature sensing is a critical parameter for EV performance and passenger safety, and automotive OEMs are prioritizing temperature sensing to reassure consumers that these novel modes of transportation are safer than internal combustion engines.