ADI and Rimac held a virtual discussion focused on topics ranging from how electric vehicles (EVs) are entering the mainstream and helping the auto industry reduce its carbon footprint to how technology from ADI is helping power Rimac’s electric C_Two model hypercar...
Analog Devices (ADI) and Rimac held a virtual discussion focused on topics ranging from how electric vehicles (EVs) are entering the mainstream and helping the auto industry reduce its carbon footprint to how technology from ADI is helping power Rimac’s completely electric C_Two model hypercar launching in 2021.
At the center of the world’s push toward a more sustainable, electrified future are EVs. EVs are fully electric cars that need at least three types of electronic units for energy conversion: DC/DC converters, typically from high voltage to 12-V to power the low-voltage electronics; a DC/AC traction inverter to drive the electric motors, typically three-phase, which supplies the power to the wheels, and AC/DC converters for recharging vehicle batteries both during braking energy recovery and from standard residential or high-power charging stations (for fast charging). According to the World Economic Forum, 215 million electric passenger vehicles will be on the road by 2030. With this rapid adoption of electric vehicles over the next decade, the demand for supporting technologies will continue to increase.
The discussion was moderated by Roger Atkins, EV influencer and founder of Electric Vehicles Outlook. Panelists included Greg Henderson, SVP of automotive, communications, and aerospace & defense at Analog Devices; Patrick Morgan, VP of automotive at Analog Devices; and Matija Gracin, director of components R&D at Rimac.
Henderson opened the panel by highlighting the seismic changes in the EV market over the past few years. They’ve transitioned from a technology novelty with a sustainability benefit to being a true performance leader in the automotive market, as evidenced by the huge investments from both pure EV and traditional OEMs in this space, and leading to shifts carmaker and supplier relationships.
“The pace of change, and the new solutions and innovations that EVs require, has challenged the traditional linear relationship, between OEMs and their technology suppliers,” noted Henderson. “OEMs are now working more directly and in tighter collaboration with technology companies.”
Designer thrusts in electric and hybrid vehicles to improve energy conversion efficiency are oriented toward devices equipped with compact packaging and assembly of high thermal reliability power electronics modules with reduced switching losses. The design parameters are different and involve power level, conversion efficiency, operating temperature in the vehicle powertrain system, thermal energy dissipation capacity, and system package.
The performance keys in the EV design are the battery and the propulsion system. “The real key is to have a battery management system — or BMS — that can accurately monitor the state of charge and transfer energy from the battery to the propulsion system in a very efficient way,” said Henderson.
As Atkins pointed out: power is nothing without control. He added, “All essential parts now, whether connected, autonomous or shared, require a lot of energy with the need to ensure that it all works efficiently and robustly. As far as adoption is concerned, we will certainly see more announcements and discussions about the path to electrification and the phasing out of the production of internal combustion engines. But we need to think about the obstacles that still stand in the way of this accelerated adoption and come up with solutions to overcome these barriers.”
The market is continuing its acceleration toward electrification. Gracin pointed out three aspects to consider as the market inexorably shifts toward EVs. The first is energy storage, which is determined by the density of the battery packs. The second is efficiency, which related not only to the battery packs but in everything about how low and high voltage is converted and managed. And the third is the infrastructure that is critical to mass market customer adoption: charging stations, repairing, and service stations.
There’s no doubt that the pandemic has had a major impact on the automotive industry, as Morgan mentioned. This pandemic has greatly accelerated technology. “An excellent driving experience has become a priority. Not only the way the car drives but also the way you feel inside the vehicle. As a result, features like immersive 3D sound, microphone arrays and voice recognition have become must-haves,” said Morgan.
He added “The cabin of an electric vehicle is so quiet, you notice the road noise a lot more. So we developed a technology that can cancel out that road noise and deliver a really immersive and enjoyable experience for the driver.”
Another aspect to consider is the range of an EV, i.e. the distance the EV can travel per charge. Morgan pointed out that this is achieved not only with the battery itself, but with the electronics that control the battery. He added, “these electronics — controlled by the BMS, have to be very accurate so that first the battery is fully charged, and then every last bit of charge is efficiently extracted out of it, reducing overall energy consumption. This is really good for the consumer, and it is good for the grid.”
One issue that Atkins has questioned is the sustainability of an EV. Battery is clearly one of the main differences between the two categories of cars (electric and the classic we know of) as it relates to the battery and what happens to it after it is past its. Whereas the traditional vehicle powered by an internal combustion engine uses heat to propel itself as well as to power the on-board services, EVs use a high voltage and capacity battery pack. When comparing the environmental impact of the two types of vehicles, one needs to take into consideration carbon dioxide emissions, a function of energy consumption in each of the phases of their respective life cycles: raw material procurement, production, use, disposal and recycling.
Gracin pointed out that there are a number of regulations that need to be complied with, both in the design and throughout the product life cycle. He also highlighted the trend of battery recycling and reuse.
“Battery packs have a second life. Once they stop meeting the performance requirements for use in a car, they can be reused for many other applications. When you take the car battery apart, there are modules and cells inside that can still be used for energy storage. We see some of the big OEMs like Renault Nissan moving in that direction,” said Gracin.
The battery management system is a critical factor in e-mobility. The addition of wireless makes it very attractive but requires a lot of care. The BMS is an electronic system for the complete control of all diagnostic and safety functions for the management of high voltage on board the vehicle and the balancing of the electric charge.
ADI recently launched a wireless BMS solution for production electric vehicles. It can eliminate the traditional wired harness, improving design flexibility and manufacturability, without compromising range and accuracy over the life of the battery.
“This technology is aimed directly at sustainability, not only because of the fact that it eliminates the wire harness all together, but all the manufacturing and complexity associated with it. It also enables the battery pack to be designed in a modular, scalable way, so that when you move into second life, you’re able to take those packs, match them for a specific application, and then reconfigure them in a way that makes sense for its second life. In addition to the weight and flexibility benefits, wBMS also enables a different way to architect a battery pack. The data captured through continuous state-of-health calculations at the battery cell and module level can be used to more accurately determine the residual value of the battery pack as it moves into its second-life phase,” said Morgan.
Batteries are at the heart of any EV, and factors such as cost and weight are the core of each challenge. What about the importance of batteries and battery-related technology?
Gracin pointed out how a sort of limit has been reached with current batteries. New challenges for batteries will have the goal to achieve better results and support green energy challenges.
“Looking back over the last 10 years or so that I’ve been in this business, not a lot of things have changed, and the discussion about lithium ion and solid state batteries is about the same today as it was a decade ago.. We are really squeezing everything out of this battery and struggling to get two millimeters inside of the packaging just to put one additional cell in there. Since the focus is on performance, we really need to put as many cells in there to extract as much power as possible, but we are reaching the limits with the current design. So a lot of innovation will need to happen to ensure an electrified future,” said Gracin.
Morgan spoke about new battery chemistries are being developed, including lithium iron phosphate (LFP) which is completely free of cobalt, a toxic and scarce mineral. EVs need a certain type of battery and high energy density. It is important that the technology can support a wide range of batteries. The second topic to consider is the cost of every EV that is battery-dominated. Over the next 2-3 years, the cost of EVs will be comparable to those with internal combustion engines.
The automotive supply chain is undergoing significant changes, both in terms of electronics and mechanicals. Software is becoming increasingly significant: the typical high-end vehicle today has around 100 million lines of software code. The BMS is playing a larger role since the battery is a fundamental pivotal feature of EVs and ensuring efficient charge management is a fundamental element for the correct operation of an EV.
Today’s batteries must have a very high energy storage density, a self-loss current close to zero, and the ability to charge in minutes instead of hours. A substantial growth in the adoption of EVs is expected in the next few years, and this will be accelerated by a reduction in market prices, the possibilities offered by different charging systems (such as fast charging, which takes a few tens of minutes to fully or almost fully recharge), and the increasing availability of charging stations in the area.