Sunday, January 31, 2010

Standard-sized batteries in electric cars, "battery-pumps", etc.

UPDATE [APR'12]: I'm surprised to see this Jan'11 story on Technology Review about the plans of Better Place to do something identical to what I've written in this post.

While I was reading an article on electric cars - focusing on Reva Electric Car Co. - in Emirates' Portfolio magazine (Issue 49, January 2010), I came across the following paragraph:

"Companies like GM and Nissan are already spending billions to develop electric cars. Carlos Ghosn, chief executive of Nissan and Renault, said recently that electric vehicles would make up 10 percent of all cars sold by 2020.

But before that can happen, both electric cars and their batteries have to become more efficient and cheaper, a whole battery-charging station infrastructure has to be created, and consumers have to want the cars, which cost considerably more than petrol-powered vehicles."

It's the text in bold that intrigued me. A thought immediately flashed - should all electric car manufacturers agree on a standardized battery specification (size, shape, electrical-characteristics, etc.), so that the consumers don't ever "own" a battery? Instead, like we have "petrol-pumps" today, we might have "battery-pumps" in the future, where a car-owner can drive in and quickly swap the nearly-drained battery (or batteries, if there is more than one) inside his car with a fully-charged pack, in perhaps <2 minutes.

As I thought more about it, I got increasingly convinced that such a system would not only eliminate (or at least mitigate) some of the key barriers to mass-adoption of electric cars, it would also behave in a manner similar to the current system of "petrol pumps", to the users, thus reducing their learning curve.

Following non-exhaustive list of factors shall drive competition among the "battery pumps":
  1. The number of battery-packs that a pump owns (its inventory)
  2. The ability of a pump to keep its inventory fully charged
  3. The price charged by a pump for a fully/partially charged pack
  4. The pricing model of a pump
  5. The quality of battery-packs available at a pump
Note on (3): Pricing might be decided on the basis of the number of kilojoules that a pump claims to deliver in a battery-pack. Alternatively, pricing might be decided on the basis of the actual distance (or energy) that a user is able to extract from the battery (measured by measurement devices inside the vehicle).

Note on (4): Could these "battery pumps" also offer prepaid subscription models analogous to those currently offered by the telcos - subscribe to a particular pump (or its chain), and they offer you either a discounted rate (since you've already paid the upcoming month's subscription-cost to them, encouraging you to buy from them), or unlimited battery replacements, or a capped number of units (e.g., first 500 minutes free, and charged after that).

A user may be allowed to charge the battery-pack(s) inside his vehicle by himself, by plugging his vehicle into a standard power socket at his home (or at a restaurant which offers complementary charging to customers). This option will allow users to self-charge their vehicles, and will further mitigate the issue of availability of charging facilities.

In summary, the model outlined above appears more effective to me than a model where each electric car manufacturer uses a proprietary type of battery (and possibly charging mechanism), leading to the same type of incompatibility and its associated perils that exist in the world of printers (ink cartridges), laptop-computers (batteries), and cell phones (chargers and batteries). We need a system akin to the CD-ROM drive, where all machines use a component with fixed specifications.

Note: Googling portions of the article revealed that it's a reproduction of this NYT story.


  1. Happy to see that my 3+ year old idea above is the way Tesla has been thinking too.

    Tesla hints at battery swap that's faster than filling gas tank, Jun'13

  2. Piaggio, KTM, Honda and Yamaha to create swappable batteries consortium