Fast charging

02Mar 2021

At a market capitalization exceeding $700 billion, Tesla enjoys a unique financial position among all auto manufacturers to expand its investments in electric vehicles and infrastructure. Special Purpose Acquisition Companies (SPAC) have taken Fisker, Lordstown Motors, Nikola, Proterra public with many other EV car companies rumored to be in the pipeline. 

These pure EV manufacturers are leveraging their access to capital to expand their market share at the fastest possible pace — they are limited by operational and supply chain challenges, not access to capital. Investors continue to applaud Tesla’s expansion strategy and pace, yet Wall Street remains shy about extending similar enthusiasm to incumbent car makers, for example General Motors and Volkswagen who have announced ambitious plans in electric vehicles. The result is an accelerating race to deliver electric vehicles with increasing performance, affordability, and choice. We are in the midst of deep disruption to the auto industry.

The entire supply chain feels the pressure to adapt to electrification. In particular traditional incumbent system suppliers (Tier-1) and component suppliers (Tier-2) are positioning themselves for the new reality. Electric vehicles contain fewer components than internal combustion engine (ICE) vehicles, and are relatively easier to assemble. Consequently, the automotive supply chain will change materially as the sales of electric vehicles (EV) dominate over the coming decade. As market forecasts show accelerating adoption of EVs, they also show rapidly declining sales of ICE vehicles putting further strain on the automotive supply chain. Expect that several companies in the automotive ecosystem may cease to exist as independent entities in this decade.

The battery itself remains the most expensive item in an electrical vehicle. The battery includes individual energy storage elements called cells that get assembled into a pack. A handful of cell manufacturers dominate the making of cells: LG Energy Solutions (formerly part of LG Chem), Samsung SDI, cATL, SK Innovation, Panasonic, BYD are the most prominent names. Most cells makers also provide the pack assembly, though some auto manufacturers, namely Tesla and the German auto makers, favor building their own packs. This points to the first tension in the supply chain: should the auto manufacturers allow the cell makers to also build the pack? There is a split opinion among auto manufacturers. 

But electric vehicles also require significant electronics and electrical systems making them a very attractive market to the supply chain. These include motors, transmissions, inverters, DC converters, on-board chargers, thermal management systems and, naturally, battery management systems (BMS). Historically, volumes were sufficiently small that the auto makers controlled or manufactured many such systems in house. For example, Tesla, GM, VW control or manufacture their electric motors and transmission systems. Traditional global Tier-1 system suppliers largely sat by the sideline. 

Historically, EV manufacturers recognized the importance of the BMS to the vehicle’s performance and safety leading them to keep significant portions of the BMS in house. But volumes were historically small; competition was virtually limited; software and system intelligence were rudimentary. Some auto makers commissioned the hardware to their suppliers (e.g., Hella built the BMS hardware for Mercedes, and LG built the BMS for GM) but kept control over the software. Once again, the traditional automotive supply chain sat by the sideline.

We now see evidence that the supply chain is changing rapidly. With the accelerating pace of EV adoption, auto makers are beginning to reach out to their traditional supply chain for help. GM was the first to outsource its BMS design and manufacture to Visteon. More Tier-1 suppliers are showing active interest in building more portions of the electric powertrain. Expect more disruption in the coming years as auto makers and Tier-1 suppliers assert their respective roles in building electric vehicles.

The fast pace of innovation is further driving disruption. In awarding the BMS to Visteon, GM saw an innovative wireless BMS solution that could shed significant battery weight by eliminating portions of the wiring harness. Rising vehicle specifications place significant emphasis on innovation in the BMS: longer range (400+ miles), very fast charging (20 minutes or less), long warranties (200,000+ miles) are only examples of this new frontier. Fleet operators, such as electric taxis, are asking for bold battery targets, for example, extended warranties reaching 500,000 miles, raising the bar even higher.

Then comes battery safety! In the fall of 2020, Hyundai recalled 82,000 Kona electric vehicles over risk of battery fires. It will cost Hyundai nearly a billion dollars to replace the batteries in these vehicles. LG Chem supplied the battery cells. Hyundai Mobis, Hyundai’s internal Tier-1 supplier, provided the BMS. LG Chem blamed the BMS. Hyundai blamed LG Chem. Battery safety in electric vehicles was now headline news, and the BMS central to the safety story. This is disruption at its best!

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04Dec 2020

When it comes to electric vehicles, there is an understanding that the battery is a fundamental component to the vehicle’s utility. Yet, there is also a false expectation that the battery can deliver all what drivers expect from an EV.  Often underestimated is the role of battery management systems (BMS) in delivering critical performance and safety, in particular, extended driving range, very fast charging, long warranties and utmost safety. I will explore this topic in more detail in a series of blogs. 

In this first part, let’s define what battery management is and does. BMS historically included the electronics (hardware) that measure voltage, current and temperature, protect the battery from current or voltage spikes, and distribute charge evenly across different cells (called cell balancing). There is a basic layer of software that computes how much charge is stored in the battery.

Generally, these are electrical systems with very little intelligence related to the chemical operation of the lithium-ion battery. There are many suppliers of such basic BMS systems, spanning smaller companies to incumbent automotive Tier-1 and Tier-2 suppliers, and some of the battery manufacturers. Most electric vehicles on the road, whether you own a Tesla, a Nissan Leaf, a BMW i3, have one of these basic BMS on board.

Future EVs demand far more performance than what present BMS are providing. Specifically:

  1. Very fast charging: Newer EVs must be able to fully charge the battery in under 20 minutes without degrading the battery. This is strictly the role of more intelligent BMS.  If you try to fast charge your EV today at a DC-fast-charging-station, you likely will not do much better than 35 minutes. The vehicle’s manufacturer will also throttle your charge if you try to DC-fast-charge too many times in a row — in order to preserve the battery’s health. An intelligent BMS should be able to lift such restrictions!
  1. Maximum driving range: Car manufacturers reduce the available charge from the battery (and the driving range) in order to guarantee the battery’s longevity. It is one of the key tradeoffs between available charge capacity, fast charging, and battery longevity (hence warranty). This, again, is the role of a more intelligent BMS.
  1. Extended battery warranty: EVs have traditionally offered 100,000 miles of warranty. But, if you look closely, the fine print warrants that only 70% of the original driving range remains after 100,000 miles. So if your EV has a nominal driving range of 300 miles, the warranty covers you only if the driving range drops below 210 miles after 100,000 miles. Not ok! Yes, you guessed it, it’s the BMS function.

Fast charging, maximum driving range, and battery warranty form a triangle of tradeoffs. An EV maker must balance these three conflicting parameters. If they add more fast charging, then they must sacrifice warranty or driving range….and vice versa. This game of whack-a-mole makes today’s EVs fall short of market expectations. Next-generation of EVs must include intelligent BMS that are able to break this limitation. The technology exists.

The intelligent BMS diagnoses the battery in real time, assesses the likely degradation mechanisms and the battery’s health at that moment in time, then dynamically makes the necessary adjustments to optimize the operation of the battery. It is “computation” meets “chemistry.” 

In part 2, I will cover the changing landscape of the supply chain.

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12Aug 2020

Three factors contribute to the mass penetration of electric vehicles:

  • Driving range that eliminates range anxiety;
  • Lower cost batteries for affordable vehicles;
  • Availability of fast charging.

A common denominator is the battery’s energy density: it is the amount of electrical energy per unit volume (or per unit weight) that a rechargeable battery can store. Energy is measured in units of kWh. Hence energy density is in units of Wh per liter (Wh/l), or Wh per kg (Wh/kg). State-of-the-art energy density figures for lithium-ion batteries stand today near 700 Wh/l and 300 Wh/kg.

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31Mar 2020

While the current situation has put us all in unfamiliar territory, one bright spot has been the willingness of so many people and organizations to offer advice and assistance. With hundreds of millions of us isolated in our homes, making especially intensive and important use of our phones and computers, it seems like an opportune moment to share four battery-specific recommendations that can help ensure your personal safety and extend the lifespans of all our devices as we adjust to this period of uncertainty, and WFH normalcy.

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09Mar 2020

Is it true that electric vehicles (EV) need 800-V battery packs for ultrafast charging? Is it true that the Porsche Taycan uses 800-V packs to enable ultrafast charging? Why did GM announce that its new battery platform will support 800 V? Let’s find out.

Let’s start with two essential ingredients required for ultrafast charging:

1. A charging station that is capable of providing a lot of electric power;

2. The ability for the battery to accept the extra charging power without being damaged or degraded.

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