Tesla’s Flex Circuit Tech Explained

Tesla Model 3


Tesla Model 3

Tesla Model 3

As if Tesla hasn’t already shaken up the automotive industry enough, the electric automaker’s new strides in flex circuit tech could change how EVs are built and potentially impact suppliers.

Suppliers of wiring and electrical components like Lear Corporation are seeing increased business opportunities as more EVs hit the market. Electric cars use an immense amount of wiring to connect all of the electrical components. The Tesla Model S and X both require about three kilometers of total wire.


A significant amount of wiring is used to connect the Tesla motor/inverter (above) with the battery pack, but this is quickly changing.

Tesla is moving forward with new flex circuit technology, which will allow for less wiring in its vehicles. The Tesla Model 3 already uses half as much wiring as the Model S and X, and CEO Elon Musk has shared that the Model Y will have 95 percent less wiring than the Model 3, at only 100 meters.

In 2013, Tesla patented certain flex circuit tech for connecting its batteries to other components. This is an example of Tesla’s push to separate itself from other automakers, and make every attempt to keep everything “in-house”. The flex circuits can reduce the amount of wires needed because each circuit can be adapted into different shapes and configurations. The company’s goal is to add more and more flex circuits throughout each vehicle’s build.

As Tesla adds more of this flex circuitry to its vehicles, the need for wires and other electrical components will obviously diminish exponentially. However, Lear Corporation doesn’t seem to be too concerned. In response to Chris McNally’s (Evercore ISI analyst) question about flex circuits’ potential to impact the company’s business, Frank Orsini from Lear responded (via Teslarati):

“The flex circuits and different types of applications in the vehicle is nothing new to Lear even. We’ve actually used flex circuits in the past. We have the technology in our product portfolio. It is more expensive technology than traditional applications of wire. What we do well in the industry is we optimize the architecture … We don’t see the usage of wire shrinking. Wires are very secured way of connecting the signaling and data communication in the vehicle.”

Regardless of analysts’ forecasts, and the assumptions of suppliers, time will tell if flex circuits are the answer, and how it impacts the EV segment as a whole. If the tech works well and is affordable, other companies will likely follow suit. However, there is surely future potential for companies like Lear to be involved in making flex circuits available for other automakers, aside from Tesla.

This is just another way that Tesla is building an advantage in the market. It’s really no different than the current situation surrounding EV batteries. Tesla makes its own battery packs in partnership with Panasonic, while other automakers need to outsource, and are facing a possible shortage.

Source: Teslarati

Categories: Tesla


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17 Comments on "Tesla’s Flex Circuit Tech Explained"

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Considering the title is “Tesla’s Flex Circuit Tech Explained” there is surprisingly litte explaining of Tesla’s Flex Circuit Tech going on.

I was thinking the exact same thing.
Perhaps the title should be “Tesla is doing something new, suppliers say meh.”

This story doesn’t make a lot of sense and almost reads like a Tesla ad. The picture makes it sound like Tesla is going to reduce the amount of cable between the inverter and battery. A flexible circuit isn’t going to help with that. That’s very high current carrying cable.

Flex circuits have been around forever. My ’87 944 uses a flex circuit on the back of the instrument cluster to connect the gages to the wiring harness. I am pretty sure they have been used similarly since the sixties (Mustangs?).

The down side to flex circuits is that they can be more fragile and if you get a short, the entire flex circuit must be replaced. They are essentially a flexible circuit board. Ironically, a traditional wiring harness is actually more flexible (pardon the pun) in that it can be reconfigured more easily.

They are lighter and cheaper.

I don’t know about costs today, but back when I used to work with them, they were more expensive than the same circuit on a typical substrate. They are susceptible to damage and protecting them adds weight and cost.

All that you saying is correct, John. Neither Flexible Printed Circuit (FPC) nor Flexible Flat Cable (FFC) is a good candidate for replacing conventional wiring. In late 90s through mid 2000s we have supplied a number of door and headliner harnesses in FPC technology. The benefit failed to outweigh the cost, so after one or two model years, OEM went back to round cable. However, the company I work for now supplies over a half a billion (yes with “B”) Flex ciruits and Flex circuit assemblies to Automotive OEMs and Tier 1s. All of them are value add and beneficial. I think Tesla will figure it out eventually, like Daimler and GM did…

Stating that a vehicle will have less wire because it is replaced with flex circuits is a bit dubious.

I still have no idea why flex circuits can remove 95% of the wires…

I agree with all the comments that say there is no explanation here, is it that each piece of wire will have switching on both ends so it can multi-task? So far it has just made me afraid of owning a car with some new complexity that 99% of mechanics/electricians/owners can’t repair.

Well I suppose since the article is erroneously named, perhaps wiki can help.


I think it means the circuit board is on a flexible substrate and is stretched from source to destination. So wire may be reduced by 95%, but circuit parts will be increased to compensate.

Looks like it’s for interconnecting cells inside the battery pack.

There’s a lot more details in the patent filing https://www.google.com/patents/US20140212695

Here’s the summary:
A system and method for improving on conventional techniques for connecting energy storage elements of a high-voltage battery pack. A tuned flexible printed circuit individually coupled to each electrode of each cell of a matrix of cells of the battery pack provides improved manufacturability and reliability.

Flex circuits have been around forever. If flex circuits made sense then companies would have been using them for interconnect before Tesla even was founded. And for all I know they did.

They would never be used to do something like connect the inverter shown because flexes have a problem, they are 2D. Sure, you can make them out of 4oz copper or such to get more thickness, but there is a limit to the thickness because it reduces their flexibility and will risk cracking as it bends.

Those wires to the inverter in those orange bundles have sufficient cross section that a flex to replace them would be awkwardly or impractically wide.

What I’m saying is that don’t let your imagination run too wild here. Flexes are not some kind of Tesla competitive advantage. They don’t have a patent on them (not one which excludes others using them). Every company out there is already considering flexes where appropriate and so if you haven’t seen them rolled out in any particular application it’s probably because they aren’t good for that particular application.

The volt has minimal wiring between its inverter and drive motor. Looks to be superior to the Tesla 3 since the orange wires visible on the ‘3’ aren’t visible on the gen 2 volt.

Bolt may not be as good but It isn’t something that is worth complaining about – which is why I don’t see the point in this advertisement. Not a big sellable feature with me.

The big appeal of the ‘3’ to me, is the 80 1/2 kwh battery or whatever it is.

Musk appeared on AutomotiveNews earlier…. THe S has 10,000 feet of wire, ‘3’ 5,000 and the forthcoming model “Y” 326.

So the press release is for a future vehicle

This is an evolutionary step.

Car makers already do this with CANBuss technology. GM reduced their large cables for EV by integrating the inverter.

What Tesla does is bring everything back to design more often than other companies. Most manufacturers are squeezing the cost out by reuse and long life cycles. With AI-assisted design and printable parts these long life cycles may no longer work.

Tesla probably needs to reduce model to model differences more. GM used the same dang V-8 distributor cap from ‘55 until ‘75. No idea how long they used HEI.