2015 Chevy Spark EV gets battery overhaul after only a year on the market

Since its launch as a 2014 model year, the Chevy Spark EV has for the most part drawn rave reviews. The heart of the 2014 Spark is its 140-hp motor that makes an incredible 402 ft-lb of torque; the miniature powerplant rockets the little EV to 60 mph in just 7.5 seconds.

Update: The 2015 edition gets a reduction in torque to 327 ft-lb.

Unfortunately, the diminutive EV has only been built as a compliance car in small numbers. With the recent announcement of changes for the 2015 model, however, the possibility arises that production volumes could be increased.

The most significant change for the one-year anniversary of the Spark EV is a major upgrade to the battery. It will be reduced from 21 kWh to 19 kWh while shedding 86 pounds, bringing the pack weight to a more reasonable 474 pounds. The new smaller pack is comprised of 192 individual lithium ion cells. Most interesting is that MSRP of $27,495 and EPA-estimated range of 82 miles at 119 MPGe are expected to remain unchanged.

These upgrades were largely made possible by a transition from A123 battery cells to those made by LG Chem, which also supplies the Volt and ELR. The new battery pack will now be assembled at GM’s Brownstone Battery Assembly Plant alongside Volt and ELR packs.

GM has clearly put some effort into redesigning the battery system to reduce its size and cost without sacrificing range. Evidently the new LG Chem cells are superior to the outgoing A123 cells, but no doubt much of the improvements come from an increased depth of discharge window that utilizes more of the battery’s capacity. Another notable change, an increased final drive ratio, also could have helped maintain rated range.

The 2015 refresh of the Spark EV increases the final drive ratio from 3.17 to 3.87 (via Inside EVs). It remains an unusually low final drive ratio for a battery electric, as competitors like the Nissan LEAF and Fiat 500e have ratios of 7.94:1 and 9.59:1, respectively. The low ratio on the Spark EV greatly reduces driveline inertia and gives the vehicle the feel of a higher “gear” than that of an EV with a significantly higher ratio.

This increase in final drive ratio should result in improved acceleration at the expense of top speed, though both are subject to electronic limitations. It also has the effect of marginally increasing city range at lower speeds, as GM found when they were initially testing both final drive ratios for the first iteration of the Spark EV. This is likely due to the greater ratio bringing city cycle operating points closer to the motor’s peak efficiency.

It is clear that the updates for the 2015 model year will help GM reduce production costs by leveraging economies of scale and bringing all of their battery production under one roof while using smaller batteries in the cars themselves.

Will these changes allow GM to boost production of the acclaimed Spark EV, and is that the company’s aim? It was recently announced that sales of the Spark EV would be expanded to Oregon as well as California, though for the time being it remains only a compliance car. It is without a doubt unusual to see changes of this nature made to a model after just one year on the market, so we will be paying close attention to GM’s long-term plans.