Why Couldn’t Tesla Motors Inc (TSLA) Just Swap Batteries?

Recently, I wrote an article about the advances in battery and other green technology that could be a risk factor for Tesla Motors Inc (NASDAQ:TSLA). A question that was raised was why Tesla couldn’t just switch to another battery technology. That’s a very good question. Here’s why it’s not as easy as it sounds, and how it could affect Tesla Motors Inc (NASDAQ:TSLA)’s stock.

Photo: Oleg Alexandrov, via Wikimedia Commons.

Is it easy to switch between batteries?
In a Congressional Research Service for Congress, Bill Canis wrote regarding the development of lithium-ion batteries, “the automaker’s decision as to which battery to procure will be in effect for a prolonged period, perhaps the life of the vehicle model, as a battery designed for one vehicle may not function optimally in another.”

He also points out that even when an automaker enters into an agreement with a battery manufacturer — as Tesla Motors Inc (NASDAQ:TSLA), Nissan Motor Co., Ltd. (ADR) (OTCBB:NSANY) and Toyota Motor Corporation (ADR) (NYSE:TM) have done with Panasonic Corporation (ADR) (OTCMKTS:PCRFY)

— the automaker is “integrally involved” in the design and production of the battery.

The reason is straightforward: Each automaker has proprietary technology that reacts in a specific way with the battery’s output and overall vehicle operations. As General Motors Company (NYSE:GM) put it, “The Volt’s battery pack design is directly coupled with the vehicle design to assure complete integration between the battery pack and the vehicle.”

Tesla Motors Inc (NASDAQ:TSLA)

In other words, each battery is designed specifically for the car it’s going to be used in — a battery made for a Tesla Model S is optimally designed for that car; a battery made for a Nissan Motor Co., Ltd. (ADR) (OTCBB:NSANY) Leaf is optimally designed for i car. More pointedly, the battery itself influences the car’s design.

Swap shop
So is Tesla Motors Inc (NASDAQ:TSLA) tied to its current battery? Absolutely not. Tesla uses a modular battery design, and as technology advances in li-ion batteries, it can swap out the cells. But that’s swapping li-ion for li-ion. As technology changes, Tesla could switch to a different battery type, but it’s not as simple as swapping one battery for another; the battery itself has to be specifically designed to integrate with Tesla Motors Inc (NASDAQ:TSLA)’s vehicles.

Consider: When Tesla designed its battery pack and electric powertrain system, it did so to meet the requirements of a li-ion battery. Tesla states: “Designing an electric powertrain and a vehicle to exploit [li-ion battery] energy efficiency has required extensive safety testing and innovation in battery packs, motors, powertrain systems and vehicle engineering. Our proprietary technology includes cooling systems, safety systems, charge balancing systems, battery engineering for vibration and environmental durability, customized motor design, and the software and electronics management systems necessary to manage battery and vehicle performance under demanding real-life driving conditions.”

Different types of batteries behave differently. More importantly, li-air batteries are still being developed, so things like specific energy, energy density, specific power, charge/discharge efficiency, self-discharge rate, and cycle durability are all theoretical. However, two known differences are size and weight — li-air batteries are smaller and lighter. Consequently, you can’t simply exchange a li-ion battery for a li-air battery.

So what does this mean for Tesla?
There are a number of ways Tesla Motors Inc (NASDAQ:TSLA) could incorporate new technology:

1. It could completely redesign its vehicles around the specifications of new battery technology — the most expensive option, and unlikely.

2. It could combine its li-ion battery with a new type of battery, as is believed to be the case with its patent for metal-air batteries — unfortunately, this still uses expensive li-ion technology.