VW’s Newest Battery Pack Facility Is Production-Line Adjacent

Designed for just-in-time delivery for Volkswagen’s first U.S.-produced EV, Chattanooga’s new battery pack assembly is highly automated.

The new and heavily automated VOA Battery Plant in Chattanooga, Tennessee, will assemble battery packs for the site-adjacent ID.4 EV assembly line. Completed packs weigh close to 500 kg/1,100 lb. (SAE)

The Volkswagen ID.4 electric vehicle (EV) is set begin localized production in the United States in early 2022. The MEB-platform, 2-row SUV will share an assembly line with the MQB-based 3-row Atlas SUV, both rolling off the line at Volkswagen of America’s (VOA) Chattanooga, Tennessee facility. Being an EV and using a different architecture, the ID.4 will require a battery-assembly plant and its own body shop, both of which VW is currently completing on the VOA Tennessee site.

Jacob Hilmes (right) is the VOA Chattanooga Battey Plant planning coordination specialist. Tim Lovvorn will serve as the facility’s production manager. (SAE)

During the recent media launch of the all-wheel-drive ID.4, Volkswagen provided an opportunity to tour the nascent battery plant and a chance to sit down with two of the engineers responsible for bringing the facility online. The battery plant will assemble and deliver complete and charged packs to the adjacent assembly line shared with Atlas. SAE Media spoke with Jacob Hilmes, who is helping create the space whole-cloth as the planning coordination specialist, and Tim Lovvorn, who will serve as its production manager, overseeing production, maintenance, and engineering. The duo has spent the better part of the last few years directing the facility’s creation from a greenfield site. An edited and condensed version of that conversation follows.

What’s been your role in the creation of this new battery pack assembly facility?

Hilmes: I've been part of the battery plant since the beginning, involved with the equipment budget, writing the specifications for the equipment and now, of course, the installation and hopefully, soon, the buy-offs to Mr. Lovvorn here.

Lovvorn: Basically, they want to hand it all over to me.

Hilmes [with laughter]: Yeah, as soon as possible.

Lovvorn: His goal is for me to sign off. “Hey, I got it. Get out of my house,” if you will.

How long a timetable for you on the project?

Hilmes: I've been on this project three years now. It started with benchmarking the other battery plants inside Volkswagen. We went around and saw different technologies and decided what makes the most sense for Chattanooga. Long story short, we decided to go with a line builder that's internal to Volkswagen out of Braunschweig [Germany], who did the first MEB battery line. This allowed us to copy and paste as much as we could, get all the lessons learned because they were through a ramp-up while we were still designing.

Of course, it's not exactly copy/paste, because Braunschweig is a component plant and Chattanooga is a car-assembly plant. We have different standards, so we adapted the Braunschweig concepts to the car-plant standards, called VASS [Volkswagen, Audi, Seat, Skoda], and it was our main benchmark. We officially awarded the project in November 2019, so we've been busy. Between the construction team and the planning team, we're at almost 30 engineers. Basically, the best way to describe it is we're all project managers, bringing in the suppliers and helping them put it together how we want it.

Would you consider the main tasks to be logistical?

Hilmes: It's coordination. The planning department is making sure that Tim will be happy with it when he gets it, that we didn't put a bunch of random technology inside it. Another big thing for us, Braunschweig uses Kuka [brand] robots. At Chattanooga, we use Fanuc. Making the Braunschweig concept fit Chattanooga is where all the real work was. The battery leaves our factory and goes directly to the car body. We'll be ready for production next year.

What have been the biggest challenges, from an engineer's perspective?

Hilmes: The COVID problem is a big challenge. We planned to use a lot of German programmers, but once they shut down travel, we were limited to what we could get, so manpower has been a big issue with the actual technical side of it. We're a German plant, and we're using German or Siemens PLCs [Programmable Logic Controllers]. It's not easy to find people that know how to program those in the U.S. Every time we fell behind, it's, “Get more people.” But there's no more people to get. It's an ongoing conversation.

What defines a good day for you as an engineer on this project?

Hilmes: Just seeing the batteries coming off the end of the line, that we're making what we wanted to make. Seeing it get put into the car body, that was the main target. It's [currently] not an everyday thing that we see batteries off the end of the line, but that's the ultimate best feeling is that we're delivering.

With a new brand of robots, is programming the main obstacle?

Hilmes: The robot picks up and places, but you're starting fresh when you change technology. You can't copy the program from Braunschweig and put it in Chattanooga, so it takes more time. When you have what we call a greenfield, an empty building, it's wide open. You can say how much space you need and you can put the equipment in as you want without hitting many constraints. But there's benefits to existing plants as well, like what they're doing in the car assembly. There's more of a push to get it done quicker. We're not stopping the Atlas from going out the door today.

When the plant handover is complete, what happens then?

Lovvorn: Actually, they start the development and we come in the middle of it. The production team has to get in place new people, new processes – how my team member puts the part in the batteries. Another IE group digs into how much time it takes and they develop step by step how many people you need, then we'll hire them in. We have to train them, and the challenge for this plant was its high voltage. You're talking 400-plus volts, so they've got to wear suits, you've got to be aware. It's a very high safety risk. We had to get our people in place to work with these guys to get the equipment running. We're learning the equipment with them and giving them open points, if you will. “This button doesn't work right. I can't see the screen. I can't reach it, it hurts my back.” That's the kind of stuff we're wearing him out with.

Hilmes: You're putting in the machines and handing it off to Tim, who has the team that has to use the equipment.

Lovvorn: Once we accept it, they're still around, but we ‘own’ it now. At that point, our maintenance team should be able to run it, maintain it and even improve it some with programming. These robots, they'll get it working, but we'll continually try to optimize it. My maintenance team will say, “Okay, that seems like a wasted motion. I can make it go faster or save some energy. It's blowing too much air off, there's too much pneumatics used.” We'll optimize that.

With a new plant, quality checks must be constant?

Lovvorn: Monitoring constantly, everybody giving us feedback. If we start seeing the dimensionality of the housing seems to be going off, we need to react to it. My team will have to go out there and analyze it and then do some action to get it back into specification. It's a constant because you're chasing single parts. You're chasing environment. They're pretty heavy [completed packs are nearly 500 kg/1100 lb.]. Just for an example, each individual module is like 40 pounds [18 kg], but one battery can have 10 of them.

With such large masses involved with battery packs, these robots must be highly specialized?

Lovvorn: Fanuc has different-sized robots. We got the second biggest one they make. In five locations in the plant, they pick the battery up, and they have to reach far with it. We call it T-Rex. They're much larger than what we're used to seeing here at the plant.

Hilmes: Six-meter reach and 1,200 kilograms. I think at the time we purchased them, they were the strongest robots in the world. Now I think they've come up with another one that might do a little bit more, but they can lift a lot. Braunschweig actually used a gantry, but because we had so much heavy handling, to not have several designs of gantries, we said, “Just use one robot. One robot, one gripper.”

Even given the difference in plant types, having a benchmark in Braunschweig must have helped with a greenfield project?

Hilmes: We've implemented quite a few lessons learned from them already. Ninety-five percent of the engineering team is actually from Germany, some are from the Braunschweig plant. They come in, and they have the contacts with Braunschweig. That way, we're constantly getting that feed of, “Hey, this gripper is not consistent enough. We changed this drawing a little bit here, and now it looks better.”

Lovvorn: Our maintenance guys, they're [visiting] Braunschweig right now. Our glue pumps are different and they have to rebuild them a lot. We know this from lessons learned. They're over there now for two weeks working with their maintenance, rebuilding these pumps just so they know what to do, what we have to look out for.

Volkswagen and its vendors are completing the final stages of bringing the new Battery Plant online in Chattanooga, Tennessee, which began as a greenfield site in November 2019 and is expected to begin serving the adjacent production facility in early 2022. (SAE)
The completed battery pack will leave the battery plant by automated delivery vehicle, to be mated with ID.4 bodies (above) at the adjacent assembly facility. (SAE)

There are multiple fastening technologies assembling battery packs?

Lovvorn: We're welding, gluing. You have special securing fasteners. We have an oven, we heat it up. A lot of test systems. Several in-line tests for leakage, voltage, lots of special checks. Cameras on the line while it's running, doing infrared checks of the battery to make sure it's not going to have a thermal event. When I first went to the plant, I thought [of the battery pack], “It's just a box. That's no big deal. I'm a production guy.” Then you start seeing all of these robots, thinking, “Well, they overdid this for show and tell...”

Once you dig into it, you realize that you've got all these parts that go together, it's a meter and a half long and can’t have half a millimeter of deviation. You start realizing that it's so tight in tolerance, each weld has to be a certain thickness. All of these little screws go around the edge, so it's got to be perfect for the top to fit on it, for it to fit in the car body. We're chasing tight tolerances with heat, weld, robots moving, all the weights. For example, if you put the battery in too early, it may break the glue loose, so now we heat it. This is all these lessons learned from Braunschweig, that we can wait two days, or we can do it in three hours because of the oven.

What's the biggest challenge of the production ramp up?

Lovvorn: We might go weeks without building something. That's the challenge of ramping up. You can only mock so much, so it's a challenge to try to keep [the team] engaged in a way that they understand why they're doing it. Right now, the teams embrace it really well. Most of the team members are willing to do anything we ask. From the production-worker perspective, you just ask them – most of them came over because they wanted something new, exciting, something different.

Once you get more and more of the battery vehicles out there and they start seeing more of it in the community, then they can always look back and say, “You know, I was part of that. We ramped that up. I didn't realize how important it was.” Some of them are very eager to do it because of the future. We’ve got to push that direction and just make sure the team members buy in. If the team members don't buy in, I lose. That's always the hardest challenge for me, trying to get them to drink the Kool-Aid with me. Because knowledge is power, we really try to communicate as much as possible.

Sharing the production line with Atlas must present challenges?

Lovvorn: We've got to make sure our part leaves to the request, fits the [ID.4] body, doesn't stop them over there, because our battery could not fit the car if we were off. I don't think that would ever happen from our checks and balances, but it's got to fit, or we'll stop them. Or they plug it in, and it doesn't work, then they've got to take this battery out for six, seven hours, or whatever. We’ve got to make sure that our part is to the right level for those guys, or we'll stop [Atlas] production. It's not just the electric car, because right now, that's a very low part of our output. I’ve got to make sure I don't hinder the other money train.