Almost a year into his new research partnership with Tesla, battery researcher Jeff Dahn has been hitting the talk circuit presenting some of his team’s recent progress. We reported last week on his talk at the International Battery Seminar from March and now we have a talk from him at MIT this week.
He went into details about why Tesla decided to work with his team and hire one of his graduate students, but he also announced that they have developed cells that can double the lifetime of the batteries in Tesla’s products – 4 years ahead of schedule.
Update: Dahn reached out to clarify that the cells in question were tested in the lab and they are not in Tesla’s products yet.
During the talk titled “Why would Tesla Motors partner with some Canadian?” – embedded below, Dahn explained how they invented a way to test battery cells in order to accurately monitor them during charging and discharging to identify causes for degradation.
Like he admitted in his talk at the International Battery Seminar in March, Dahn doesn’t claim that he understands perfectly the chemistry behind the degradation, but the machines that they developed enabled them to test new chemistries more accurately and much faster – resulting in significant discoveries for the longevity of the cells.
One of his students working on the project went on to work for Tesla’s in-house battery cell research group and another started a company to commercialize the battery cell testing machines that they developed. Their client list includes Tesla, but also Apple, GM, 24M, and plenty of other large battery manufacturers and consumers.
In the second half of the talk, he explained how their new testing methods led them to discover that a certain aluminum coating outperformed any other material. The cells tested showed barely any degradation under high numbers of cycles at moderate temperature and only little degradation even in difficult conditions.
When it was time to talk about how those discoveries are impacting Tesla’s products, Dahn asked to stop recording the talk in order to go into the details.
While we couldn’t get that valuable information, when they started recording again, it was for a Q&A session and the first question was about his team’s ultimate goal for the lifetime of li-ion batteries.
He hesitated to answer, but then he said:
“In the description of the [Tesla] project that we sent to NSERC (Natural Sciences and Engineering Research Council of Canada) to get matching funds from the government for the project, I wrote down the goal of doubling the lifetime of the cells used in the Tesla products at the same upper cutoff voltage. We exceeded that in round one. OK? So that was the goal of the project and it has already been exceeded. We are not going to stop – obviously – we have another four years to go. We are going to go as far as we can.”
This is impressive, especially since their research partnership started only in June 2016 and in February 2017, Dahn said that his team’s research is already “going into the company’s products“ – just a month after Tesla and Panasonic started production of their new ‘2170’ battery cell at Gigafactory 1 in Nevada.
It’s not necessarily related, but the timing is certainly interesting. It can take some time for products successfully tested in the lab to make it to production products.
It’s also important to note that Dahn’s research was focusing on Nickel Manganese Cobalt Oxide (NMC) battery cells, which Tesla uses for its stationary storage products (Powerwall and Powerpack), and the first cell production at Gigafactory 1 was for those products.
Dahn explained that by increasing the lifetime of those batteries, Tesla is reducing the cost of delivered kWh for its residential and utility-scale projects. He gave examples of the costs at $0.23 per kWh for residential solar with storage and $0.139 per kWh for utility-scale, based on Tesla’s current projects:
For the batteries in its vehicles, Tesla uses Nickel Cobalt Aluminum Oxide (NCA) and Dahn said that they are also working on this chemistry. Tesla and Panasonic are planning to start production of battery cells for vehicles, starting with the Model 3, at Gigafactory 1 by June 2017.
He added that considering Tesla’s use of aluminum in its chassis, there’s no reason why both the cars and the batteries couldn’t last 20 years.
Here’s the talk in full (update: MIT made the video private after we published our article):
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