Post-Volt: E-REV Batteries

I was thinking about what a post-Volt landscape would look like. When the clock ticks over into 2021 and the first Volt’s off the line have the battery warranties expire, where will people go from there. Do you pull out the existing Volt battery pack and replace it with a newer, lighter, cheaper replacement battery pack? Will it be worth it for those future battery packs? What kind of other choices will you have?

Based on a study by an independent Japanese administrative group called NEDO, or New Energy and Industrial Technology Development Organization, by 2020 the target for Lithium-ion batteries for vehicles is 250Wh/kg and 1500W/kg for about $250/kWh. This sounds pretty ideal – if it becomes reality, a 12kWh Volt replacement pack built on this technology would only cost about $3,000, compared to the estimated $8,000-10,000 at the time the Volt enters manufacturing. Not only that, but the estimated weight of the pack would be slimmed down from 400lbs to 150lbs, a reduction of 62% which would help out the vehicles performance characteristics.

There are a few other battery characteristics to figure in, the depth of discharge, cycle counts, thermal stability and pack sturdiness (for crash tests). Batteries that can stand up to the roughly 3,500 cycles required to fulfill the warranty obligations are not too far away – Lithium Titanate (LTO) batteries offer the high cycle count even at higher charge and discharge rates, but they lag in kWh/kg and W/kg.

In the short term, they estimated that today’s battery packs cost about $2,000 for 100Wh/kg and 400W/kg. However, they figure that the price will be cut in half by this time next year, and the price will only sink from there, with performance increasing.

GM corroborates this viewpoint – they recently refuted a CMU study that indicated the Volt’s $1,000/kWh battery pack would be far too expensive for GM to swallow. GM said that their estimate was “many hundreds of dollars” per kWh above what GM’s actual battery pack costs are, with a goal of $250/kWh. If we guess that “many” is at least 2 and at most 4, then the battery pack would cost between $9,600 and $12,800. GM touts their cost savings for future Volt generations, although the generation 2 and 3 E-REVs wont hit until about 2014 and 2017, respectively. If Gen 2 and Gen 3 have pack prices of $500 and $350Wh/kg, along with better cycle life and depth of discharge, reducing the size of the pack from 16kWh to 12kWh, unit prices of the Volt could drop down from $40,000 closer to $30,000 and $25,000. This is low enough to allow GM and other companies to come in and offer full-sized sedans and mid-sized SUVs.

Sometimes I wonder if the Volt is a lot like the new Boeing 787. Granted, GM seems to have a smoother development cycle that Boeing has had (the plane is 2 years late), but they’re both groundbreaking in their field, designed to be more efficient. Boeing is using carbon fiber to replace aluminum, and GM is switching to run primarily on electricity. I have high hopes for both projects, they are both critical to the green future.