The role of Battery Management Systems in Autonomous Drive
Battery management in automotive goes far beyond just managing the battery cells and keeping the pack healthy, it involves ensuring the safe operation of the pack, interfacing to the load and keeping the battery working under ideal conditions right across its State of Charge (SoC) range..
As batteries for automobiles get lighter and stronger, they become not only more powerful but also more dangerous. The search for battery materials that mix power and longevity must also be a search for safety, with measures taken to decrease flammability and explosiveness.
The reactions taking place within batteries, chemical interactions that produce heat and transfer energy, had for years been a destructive force on the battery itself, with deterioration levels varying from slow to nearly instantaneous. Purging excess heat is only one challenge to battery management. In autonomous vehicles (AVs) increased sensors that operating at differing voltages and speeds, add not only heat but also a wide and varying workload onto the battery as its vehicle maneuvers without a driver.
Newer batteries, still in research and development, which will use materials and perform chemical reactions, will need even stronger and more precise battery management technology; according to an article that also notes the vast differences in power and efficiency between batteries and fossil fuels. The author said that regulations cannot solely be relied upon to enforce safety rules for battery management, which must become more accurate and reliable as batteries become more powerful. Even the most well-made battery units have an unpredictable life expectancy and an unknown speed for decline in performance.
Autonomous vehicles present additional opportunities and challenges for designers: batteries must also be protected from errors and cyber attacks via wireless networks, this creates a need for increased and more powerful security systems within networks.
All-electric, ready to take off?
The auto industry is poised to dramatically increase the production of all-electric vehicles. Production over next several years will naturally depend on advances within battery technology.
Since the aim of car companies remains the manufacturing of affordable, manned passenger and freight vehicles; responding to safety concerns for autonomous vehicles remains difficult.
It is generally accepted that over the next few years, we will see a variety of tests in the transport of people from one place to another, over targeted routes.
The routes which will include a multitude or starts and stops will impact acceleration and influence the pace in which fast voltage changes can be made, with varied load demands on the battery.
This reality remains a great challenge in battery-operated self-driving vehicles (SDV). Learn here more.
Multi-powered vehicles and sensors
In any controlled condition, drive functions can be more acutely monitored; the tighter the route, the more often external monitors can be used to track systems. Not every SDV route-driven vehicles will be all-electric. A combination of fuel types will run vehicles for many years to come. Below we will look at the battery/fossil fuel management systems for autonomous vehicles that run mostly enclosed routes.
A recent article lists, in a nutshell, the necessary components for next generation controlling sensors for batteries. Developed for current and future lithium-ion battery packs, the sensor system uses asynchronous network technology to capture battery voltage information and is particularly efficient in high electrical noise environment. Read here more about the safety features.
A complex and confounding power issue
The complexity of the battery power/safety dichotomy and management of constantly changing voltage is shown in a patent application for “Battery management systems for autonomous vehicles,” a United States patent pending since 2015 through Qualcomm, Inc.
This patent, while mainly addressing systems for unmanned flight drones and other UAVs, addresses most of the concerns designers have about high-voltage management.
The patent addresses problems with extreme power use like takeoffs in aircraft, very similar to acceleration in ground vehicles. The various discharges and recharging modes affect batteries in different ways; li-ion batteries now in use all vary in the ratio of energy storage and power production.
Whether airborne or ground based, the battery management of transportation batteries must include controlling two or more batteries of different voltages and output. Since battery technology today consists of many interrelated cells, any of which can cause a problem for the system, management is a multifaceted set of controllers, constant power for those controllers and reset/troubleshooting devices, the patent said.
Power conversion and control is the key, “A power control element for managing a high energy density battery and a high-power density battery, during a plurality of operational modes in an autonomous vehicle according to various embodiments, may include a power converter element coupled to a first battery, a second battery, and an autonomous vehicle.”
A complex and confounding power issue
Are you involved in this topic and do you want to learn more? The 5th International Conference Automotive Battery Management Systems, produced by IQPC GmbH, will be held in Frankfurt, Germany between 18 – 20 September 2018.
The conference will focus on the advancements of BMS for EV/HEV with case studies from senior practitioners working on the latest innovation for autonomous cars, fast charging technologies and optimization of lithium-ion batteries for passenger and commercial cars.
Meet experts from Volvo Bus Corp., Jaguar Land Rover, Mitsubishi, Solaris Bus & Coach, Audi, Infineon, Manga Powertrain, Tesla and many more. The conference offers 2 full days with insights from global leading experts, 4 interactive workshops, and in-depth networking opportunities to ensure participants gain lifetime value from the event.
DO NOT MISS THE CHANCE OF:
- Discussing how to deal with system requirements influence on battery hardware and software
- Getting a deeper understanding of your battery: Monitoring, testing and simulation tools
- Learning how to implement functional safety for batteries
- Networking with traditional and innovative OEMs, as well as leading Tier 1 companies
For more information click here.
Source: iStock / sanjeri