Nissan LEAF battery capacity loss – last in a series

What does it all mean?

For the last several weeks, Living LEAF has been writing about the loss of battery capacity in the Nissan LEAF. Owners on the My Nissan LEAF (MNL) forum have devoted over 3,000 posts to this topic alone, making it the most discussed topic on the forum. After reading the first thousand posts, we have learned a great deal about the issue, how Nissan owners feel about the issue, and as importantly, we have learned what Nissan North America’s first response to this issue has been. In this last article in the series, we will provide our views on the topic. As this is a dynamic situation, the numbers will continue to change. We have chosen this particular point in time to create a summation of the situation as we see it. We will continue to make our way through the remaining posts, and will periodically provide any updates to our thoughts as needed.

Vehicles affected to date

To date, there have been 68 reported instances of a loss of one battery capacity segment, or 15 percent of battery capacity. Of those, 29 owners have reported the loss of two battery capacity segments (21.25 percent of capacity) and 7 owners have reported the loss of three battery capacity segments (27.5 percent of capacity). These battery capacity segment losses are only those as reported on the MNL forum. There are likely others not reported on the forum, but with almost 6,000 forum members, we feel that this is a good representation of Nissan LEAF owners in the United States along with interested others. These battery capacity loss numbers continue to rise on a weekly basis, but not an escalating one. That is, the problem of battery capacity loss in the United States does not seem to be worsening over time, but continuing at a low sustainable rate. Finally, this issue is primarily although not exclusively focused in areas of the country that experience high ambient temperatures for extended periods of time.

A closer look reveals that of all of the one segment losers, not all of those that reported the earliest losses have gone on to lose another segment. While most have, there appears to be at least two of the earliest losers that have not lost a second segment yet. Also, it is fair to note that some of those that have lost three segments lost their first segment after others did.

Nissan has sold over 13,000 LEAFs in the United States. 68 divided by 13,000 equates to a fraction of one percent. Nissan has sold over 25,000 LEAFs globally. For anyone to claim that this is a widespread issue to date, they are just not studying the same data that we are. Nissan has sold over 400 LEAFs in Arizona. Of the 68 one segment (or more) losers to date, 40 reside in Arizona. While we cannot sort MNL forum members by state, we would have to think that there are more than 40 that live in Arizona. This would indicate that at least some LEAF owners that live in Arizona and are active on the MNL forum have not yet lost one segment. Also, we have reported in our earlier articles about a Northwest LEAF owner with over 35,000 miles and no battery degradation. He has updated his information and states that he is now over 47,000 miles with no full segments of battery capacity loss, though he reports that his range has been reduced by eight to ten percent. Given the accumulation of 47,000 miles in just over 15 months some battery capacity loss is to be expected. There was also a report from a manager at the California Center for Sustainable Energy of a California LEAF owner with 40,000 miles that had just lost a battery capacity segment. We suspect that there are others with significantly more than 25,000 miles with no or minimal reduction in battery capacity.

A quality issue?

Six Sigma is a quality management process. A six sigma process is one in which 99.99966 percent of the products manufactured are statistically expected to be free of defects. If all 25,000 Nissan LEAFs sold to date conformed with Six Sigma 24,999.9 of them would be defect free. While an admirable goal, we don’t know how many manufacturers of any product can produce with such a low level of defects.

At issue here though is not the LEAF in its entirety, but its traction battery. More specifically, the cells that make up that battery. Each LEAF uses 192 Lithium-ion cells housed in 48 modules making up one battery pack. 25,000 LEAFs contain 4,800,000 individual cells. If each of these cells conformed to Six Sigma quality, 4,799,984 of these cells would be defect free. A basic law of statistics states that in a normal distribution, nearly all values lie within three standard deviations of the mean, or 99.73 percent. This means that of 25,000 LEAFs sold, 24,933 would fall within the normal distribution. But let’s apply the normal distribution curve to the manufacture of our LEAF Lithium-ion battery cells. If 99.73 percent of all cells produced are perfect, that means that 12,960 are not – far from Six Sigma near perfection. Sprinkle a few of these cells throughout the production line, have those vehicles end up in high ambient temperature conditions, and it is not too difficult to see how a situation such as what is currently developing could occur. And this is assuming a 99.73 percent rate of perfection of manufacture of the individual battery cells, or just meeting the parameters of normal distribution.

Nissan LEAF owners view

Nissan LEAF owners that have lost one or more battery capacity segments are generally unhappy. This is an understandable point of view. Some have decided that it may be in their best interest to pursue a class action against Nissan, with apparently at least one law firm already seeking potential litigants. Other LEAF owners that have not been directly impacted by the loss of battery capacity are concerned about future battery capacity loss, possible reduction in driving range, and potential reduction in resale value. These owners do have valid concerns, however, we do not see that those considering seeking legal action have a strong position.

While we are not lawyers, we do have the capacity to think for ourselves. If less than one percent of a class has a complaint, we find it hard to believe that any court, Federal or State, would view it as a valid complaint. We also find it difficult to present any scenario where the class would consist of every Nissan LEAF, as it has already been shown that over 99 percent have not presented with this complaint. We suppose that the class could consist of Nissan LEAFs sold in Arizona but would any reputable law firm wish to take on a multi-billion dollar corporation for the sake of 400 individuals? With what at stake? There are no punitive damages. There is no loss of income. There are no injuries or medical claims. Ultimately, your car will not drive you as far as you thought it would. Should it come to this, we see a law firm collecting potentially millions to settle a claim, while Nissan LEAF class members get a coupon for ten percent off of their next Nissan purchase.

So where does that leave us? Looking to other solutions – primarily working with Nissan North America directly.

Nissan’s record in dealing with previous manufacturing quality defects

The manufacturer does not exist that builds defect free, or we would even wager to say Six Sigma level defect free, products. It is reasonable to expect that a new technology product may see greater challenges than an established product. As diligently as Nissan has tried to present a high quality product – and they have, in part based on the extremely slow ramp-up of initial LEAF production in Oppama, Japan – it is unreasonable to expect the product to be perfect in all situations and in every instance. Should Nissan have seen this coming? Absolutely. That they did not see this coming tells us that the level of testing performed did not mimic real-world use.

The first article in our series detailed the care and feeding of the Nissan LEAF battery. It is likely that hot weather testing at Nissan’s Arizona Test Center (ATC) conformed to these recommendations as much as possible. In the real world most owners of any automobile don’t even open the Owner’s Manual, much less read any recommendations to be found inside. We recently wrote that if we were part of the decision making process at Nissan we would have a small fleet of LEAFs circling the five mile ATC oval at top speed only stopping to change drivers and quick charge the battery. Driving 16 hours per day and charging the other 8 each of these cars would accumulate over 45,000 miles in 30 days. Do this with just five cars and Nissan would be provided with a wealth of real-world torture test information that could then be applied to their continuing decision making process. Just over two months of this would provide 500,000 miles of real world, high ambient temperature, torture test results. Would all of the cars make it? We don’t know. That’s the point of the test. This test regimen should have been started as soon as Nissan learned of the extent of the problem in hot climate areas. If management looks at the cost of the testing program and decides that it is too expensive, the next question is obvious – what is the cost of not doing it?

Nissan, as do all auto makers, has had to deal with manufacturing problems of various sorts over the years. One particularly visible issue related to Nissan’s continuously variable transmission (CVT). Nissan introduced the CVT to United States car buyers in 2003 in the then new Nissan Murano. The Murano is a mid-sized crossover vehicle with Nissan’s V6 engine. It was provided with a CVT as the only transmission choice to provide two things – good fuel economy and a smooth driving experience. The CVT was introduced in the sedans in the Nissan line-up in 2007 and is currently offered in several Nissan vehicles. Globally, Nissan had been using the CVT design since the early ’90s for its efficiency versus a conventional automatic transmission. Nissan’s application of the CVT in the Murano and Maxima, with their high torque V6 engines, put more strain on the transmission design than Nissan had anticipated. Over time, CVT failure was seen in a small percentage of these vehicles, some of which failed beyond the original five year or 60,000 mile powertrain warranty. There was never any safety recall issued in connection with these failures. Nissan elected to double the original warranty on the CVT to ten years or 120,000 miles. The CVT extended warranty included all Nissan vehicles provided with a CVT for model years from 2003 through 2010. There is no additional cost for this coverage, and it is transferable to all future owners. Which means that if you are the owner of a 2003 Murano with less than 120,000 miles your Murano CVT is only just now approaching the end of this extended warranty period, even if you are not the original owner. Others will obtain the benefit of this program for years to come. Nissan also reduced the price of replacement CVTs if needed beyond the extended warranty. It took time for Nissan to realize the extent to which CVT failures were making themselves known, just as now it is taking time for LEAF battery capacity loss issues to make themselves known.

In sum, we expect that after reviewing the situation, gathering data, and analyzing the results of what we hope is ongoing testing, Nissan will come up with a reasonable solution. They have proven before they are capable of doing so in the face of an unfortunate situation. This particular situation is unfortunate for those impacted directly by the loss of battery capacity. It is unfortunate for Nissan, as this has already likely influenced consumer behavior as this news has moved slowly into the mainstream press. And, perhaps most of all, it is unfortunate for the nascent EV community as a whole. We do however, hold out the hope that the resolution, when finally reached, will move the state of the EV movement forward rather than backward. This situation mirrors our question mark at the top of the page – it is rough, unfinished, and has many incomplete areas. We believe that Nissan is working hard to finish the question mark properly. And that it will show that sometimes being bold, and being the first to leap into the water, while risky, can lead to greater accomplishments earned through greater trials.