Does Tesla Have A Brand-New World-Beating Battery?
Sept. 16, 2019
A research paper and two patent applications point to a potential Tesla advantage, but as usual this development is being hyped beyond reason.
With Tesla's battery research partner publishing a paper about an exciting new long-life cell theoretically capable of a million miles in an electric vehicle, it isn't surprising that some pro-Tesla blogs are running wild with the news.
According to Electrek , whose editor and chief writer Fred Lambert is a Tesla investor, Jeff Dahn of Dalhousie University has "released test results for an impressive new battery cell that is going to be Tesla’s new million-mile battery, according to a source familiar with the matter." "Read the paper and weep or even better, read the paper, sell your short position and get excited about the future," Lambert tweeted after posting his story on the new Dahn paper.
Anyone familiar with Lambert and Electrek's long history of overhyping Tesla has come to expect this kind of hyperbole, but Lambert's reporting leaves out some incredibly important information about the cells that Dahn describes in his recent paper. It's not just that the path from research to industrial-scale manufacturing is long and fraught: Lambert fails to mention that the cells Dahn describes aren't Tesla's unique intellectual property or that Tesla would need to completely re-engineer its entire battery pack architecture to use them. It doesn't take a battery expert to understand these realities and their implications, leaving the reader to wonder why Lambert might have left these details out of his reporting.
Indeed, these facts are apparent to a decided non-expert (yours truly) on the first read of Dahn's paper, which describes "single crystal" NMC352 pouch cells obtained from a company called Li FUN Technology, of ZhuZhou City, Hunan Province, China that use artificial graphite electrodes, also sourced from China. Li FUN's cathode isn't new, nor are the materials used in the electrolytes that Dahn's researchers filled the supplied pouches with. Rather than developing a completely new cathode or electrode chemistry or manufacturing technique, which might give Tesla a wholly novel and unique battery type, Dahn's work is clearly tweaking and optimizing established experimental battery types.
A pair of subsequent patent application s does point to what seems to be the only defensible intellectual property to come out of this research so far: the ability to achieve long life battery performance using just two electrolyte additives. These are the first patents from Dahn specifically covering a novel battery chemistry to be assigned to Tesla as part of the partnership between the researcher and the EV maker (and only the second and third Dahn-Tesla patents overall).
According to these applications, Dahn and Tesla have identified two-additive electrolyte systems that offer the improved lifecycle described in Dahn's research paper using two electrolyte additives (combining vinylene carbonate with 2-furanone or 1,2,6-oxodithiane-2,2,6,6-tetraoxide) rather than three or more. These patents state that "researchers typically do not understand the interaction between different additives that allow them to work together synergistically with the electrolyte and specific positive and negative electrodes," and that "the identity of certain systems is often based on trial and error and cannot be predicted beforehand."
The patent applications' language makes it clear that the key benefit to this breakthrough is the potential for cost and complexity reduction on the manufacturing side, which is of course could result a significant commercial advantage. One of the applications specifically covers "the fabrication of rechargeable battery cells, and more specifically, to the post-assembly formation, and testing process of rechargeable battery cells." This taps into the narrative that Tesla may someday no longer need its faltering Panasonic partnership, but for this new intellectual property to come to market Tesla still needs other partners to source critical components like the NMC352 cathode and artificial graphite electrode from Li FUN or other manufacturers.
Though Tesla may have patented advantages on the electrolyte side, the Canadian cathode manufacturing firm NanoONE points out in an informational email that "single crystal NMC materials can be expensive to manufacture." According to NanoONE, "the results [of Dahn's research" demonstrates what NMC pouch cells are truly capable of regarding stability and durability." Because Dahn's paper is "short on details," it's not at all clear that the cost benefits of two-additive electrolytes isn't outweighed by the additional cost of moving to single-crystal NMC cathodes which depends on the supplier [Ed: NanoONE has patented a single-step single-crystal NMC cathode manufacturing process].
Another critical factor in any eventual commercialization of this battery technology evolution involves form factor: Dahn's research took place using small prismatic cells, slightly larger than a Canadian $2 "toonie" coin, and not the 18650 or 2170 cylindrical cells Tesla uses. Bringing these cells to market would require entirely new manufacturing techniques on the cathode, electrode and cell level as well as an entire re-architecting of Tesla's battery pack design and accompanying manufacturing changes. Though hardly impossible, these requirements would be incredibly capital-intensive for Tesla to do alone and would require a fundamental shift away from Tesla's unique cylindrical cell-centric knowledge base. That is, unless the demonstrated levels of performance can be replicated in cylindrical cells that have very different specific energy, energy density and surface area characteristics.
Ever since Tesla started building its first vehicle, it has been expecting breakthrough developments in available battery chemistries. This is why it uses cylindrical cells, like the 18650 and 2170 form factors: these are usually where new chemistries are first available at scale, and Tesla hoped that by using them it would be able to plug new chemistries into its existing battery pack architectures ahead of the competition. Instead, what has happened is that relatively minor tweaks to existing chemistries and cathode/electrode/electrolyte makeup and manufacturing tweaks have made steady improvements rather than the hoped-for quantum leaps.
The new breakthroughs from Dahn's lab, at least the ones that have resulted in defensible intellectual property for Tesla, appear to be more of this evolutionary progress. Though the performance benchmark demonstrated is extremely impressive, it more strongly suggests that Tesla's current cylindrical NCA cells are a dead-end than it demonstrates a completely novel class of batteries or even a tweak that can be readily deployed to Tesla's vehicles in the near term.
Dahn's research has rightly generated considerable excitement in the battery and EV communities, and should be celebrated. But if the auto industry has a single lesson to teach, it's that the path from invention to true innovation in this complex and dangerous product class is long and that the devil is in the details. As difficult as it is for observers to understand the breakthrough he has made, we have far more to learn about what will be required to bring Dahn's developments to mass-produced vehicles on the public road.
Casting light on that path from lab breakthrough to viable product, not hyping the hypothetical best-case scenario is the proper place of the media here. Hopefully, Tesla and Dahn will help contribute to that process rather than shrouding this work in mystery in order to maximize hype. In the meantime, anyone hoping to separate reality from hype will continue to have to read primary research and patent applications extremely closely.
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