Panasonic is constantly improving battery-production techniques at the Nevada Gigafactory. (Tesla)

CES 2021: Panasonic races to keep pace with EV battery demand

Lightning-paced development of lithium-ion technology and production techniques is always ongoing, according to two of its top battery engineers.

As part of its series of virtual Tech Talks at the 2021 Consumer Electronics Show (CES), Panasonic hosted two of its key battery engineers to discuss the fast-paced development of the cylindrical lithium-ion cells being produced at Tesla’s Gigafactory in Nevada. Providing insights into battery-production logistics, scale and automation were Panasonic Corporation’s Shawn Watanabe, head of energy technology and manufacturing, and Celina Mikolajczak, VP of battery technology for Panasonic Energy of North America. An edited subset of their discussion:

Q: How long has Panasonic been in the lithium-ion battery game?
Shawn Watanabe (SW): [We] have provided lithium-ion batteries from 1994. We started to do business for Tesla [in] 2012, with the very small 1865 [form factor] lithium-ion battery we provided to Tesla for the Model S. For more than eight years, Panasonic have supplied the battery and its updates for the updated Model S, and currently we’re in [the battery’s] fourth generation, meaning updates to capacity, safety and lower cost.

Q: When you started the Tesla partnership, did you know how fast development would move?
Celina Mikolajczak (CM): I was at Tesla working with Watanabe-san during a lot of that time. And the speed at which we were continuously improving the cells that we were putting in the Model S and then developing for Model 3 was fast by anyone's standard. It even surprised us inside Tesla about how fast we had to go. No sooner had we finished and brought a cell under production and started producing with it, we were already working with Panasonic on the design of the next cell. It's been continuous improvement, continuous technology development. No resting on laurels, just onto the next.

Q: What’s that pace like now for Panasonic, with multiple big competitors working on lithium-ion cells for electric vehicles?
SW: For example, we provided the 1865 small cell for the Model S and X, and we’ve already achieved shipping 3 billion cells to Tesla. And the 2170 cell for the Model 3, [we’ve] also already achieved the 3-billionth cell. So this means [that a] huge supply chain had to be built up. It means we have to collaborate with so many chemical suppliers on materials.

CM: It's kind of like orchestrating a symphony, because you've got so many different organizations within Panasonic having to bring together their expertise. And as Watanabe-san pointed out, we have to worry about our supply chain. If we're going to build at the scale that Tesla needs, or the electric-vehicle industry needs, you are buying not in kilograms, but in tons, or hundreds of tons of material. And that means a lot from the supply chain, it means a lot from logistics. Then you bring it into the factory and you go through a lot of complex processes to make a cell.

And then if we're going to update the technology – we've been introducing a higher energy-density cell at the Gigafactory – it becomes more like orchestrating a fugue. Where we've got one cell model running on some lines, we've got another cell model running on other lines, we are converting lines as we go, we've got new materials coming in. Getting it perfectly right takes the effort of hundreds, if not thousands of people.

Q: What are other challenges trying to manufacture these small cells at scale?
CM: The manufacturing process is moving very, very fast. So if you make a mistake, you have to find it quickly or you're going to make an enormous amount of scrap. The stakes are really high, there's no dawdling. If you think there's a problem with manufacturing, you have to make a decision quickly. And of course, if you stop, you have to move quickly to resolve whatever issue there is, because we look at our output in millions of cells a day. And our customer needs these millions of cells a day to be able to produce the volumes they need to achieve supply to the customers outside.

This is not going to be a uniquely Tesla problem. This is going to be a problem for the EV market in general. Any cell size that you deal with, you’re going to be producing huge volumes of electrode, and that has to be produced very quickly and you still have to make the cells. It’s very fast-paced. It's adrenaline-raising to be in the factory, there is a buzz, a constant hum because everything is happening so fast.

Q: What goes into automating a process like this?
CM: The process is tremendously automated. One of the big challenges to my engineering team is to continuously add automation, add sensors to our equipment. So we continuously look for areas where there might be a manual quality check. Can we automate the quality check? Somewhere where an adjustment needs to be made, can we apply sensors to determine that the adjustment has to be made and make it automatically? To continue to grow and scale, there is no way we can achieve the ambitions we want if we don't automate. Frankly, our parking lot will not hold all the [employee] cars we would need if we didn't really focus on automation.

SW: Fifty or 60% of the equipment in-house is Panasonic production equipment. We designed it for the best forecast on the high energy-density cell. It was challenging and [initially] 300 or 400 Japanese engineers moved to the Reno area. Everyone stayed for a long time in hotels and [worked on how to adapt], and improve [the equipment] and how to introduce and transfer [expertise] to the local staff.

CM: As Watanabe-san pointed out, to start this factory, hundreds of engineers came from Japan to work on this equipment, to tune it, to make sure that it was operating effectively. That group brought the equipment up and started hiring local engineers, local members, and that team has taken over running this equipment. Now we've got about 250 members of the engineering team locally, plus some expats and some folks still coming from Japan, some very good engineers coming to continue to evolve our equipment, evolve the automation. Before we try something on a production line, or before we attempt to run it, we're going to go through multiple trials to make sure that the processes we're trying to automate are actually going to do the things we need them to do.

Q: What role does recycling plays in this process?
CM: First we try to minimize scrap at all cost, because it means you're not producing good material. At the same time, any production process will produce certain amounts of scrap. Obviously, the materials we use are very valuable. We use a lot of copper, we use aluminum. Just from their metals content, they are very valuable and you want to recover them because it took a lot of effort to originally produce these metals from their ores. Our long-term goal with Redwood [Materials] [https://www.redwoodmaterials.com/ ] is that we want to recycle those back into the cell supply chain. If we’ve got cathode material going to them, we want to break that down to your precursors and send that back through the cathode making process.

If we're scrapping copper, we would sure like that to be turned into new copper foil for us. And obviously our own scrap is not going to supply our massive production because it's only a very small fraction of what we produce. So one of the things that's interesting about Redwood is that they're pulling cells and scrap from all over the country. So it's a steady stream of raw materials that could become an appreciable part of our supply chain, at least for certain materials. That's our long-term goal.

Q: Can you talk about progress on making a cobalt-free battery?
SW: It’s really changed from 1994. When Panasonic started manufacturing the lithium-ion battery, at that time, the cobalt content in the cell material was 100%. [Since then], we’ve decreased cobalt about 85%. Cobalt is a key material [that effects] many things [such as] cycle life and safety. How to design this scientific material and how to mass produce it is the real challenge. We are now planning our technology roadmap, [and] two to three years [from now], we can introduce a real cobalt-free, high-energy-density cell.

CM: The manufacturing, if you drop the cobalt content, becomes harder and harder. You have a lot more moisture sensitivity. But it's something that is important societally, and it's also something that helps with cost. Cobalt is expensive. So this is one of those things where reducing cobalt makes it harder for us to manufacture, but ultimately does reduce the negative environmental impact of batteries and reduces the cost.

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