Solid-state robot batteries cost 4x more than lithium-ion — SK On sets the bar

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SK On says solid-state cells can give industrial robots the 8+ hour runtime of a human shift, but adoption might be another story

While upcoming solid-state batteries boost productivity through longer operating times and lower overall operating costs, they are prohibitively more expensive than some of their lithium-ion peers

Modern Li-on-based batteries are under 2% of a robot's manufacturing cost today, and solid-state would push that share to around 8%, a premium that could come with serious tradeoffs for manufacturers

Modern robotics is a field that continues to grow over time, fueled by a mix of smarter AI, manufacturing efficiencies and at times, better materials that change what is possible on the ground.

The robots currently in use in factories and warehouses however have a key limitation that has yet to be addressed properly: Lithium-ion batteries often can not keep up with the power demand that modern robots have.

This is particularly reflected in how often they require a battery swap or a recharge: most lithium-ion-powered robots typically operate for one to two hours on a charge, a far cry from the industry's ambitions of machines that can work a full eight-hour shift.

A costly solution to a robot's current battery limits

Speaking at the 2nd Battery Foundry Forum in Seoul on July 15 2026, Ko Young-seok, the executive vice president and head of product planning at the Korean battery maker SK On, argued that solid-state cells can deliver meaningful value for industrial robots that need extended runtime.

He also explained that whether manufacturers actually adopt them will come down to total cost of ownership (TCO), weighed against two cheaper rival approaches: battery swapping and ultra-fast charging.

The TCO framing implies that solid-state batteries, the battery industry's most hyped next-generation technology and inherently expensive to boot, might attract industrial buyers simply because the math works in their favor relative to conventional Li-ion setups.

This is because one must factor in the cost of keeping spare battery packs, charging and/or swap times, and potentially additional robots to cover the resulting downtime, which could leave solid-state with a lower TCO than the competition despite the higher sticker price.

The framing may also be unavoidable given how batteries sit in a robot's bill of materials today. A Li-ion battery accounts for under 2% of the total cost of an industrial robot, according to SK On, essentially a rounding error in the grand scheme of things, but switching to a solid-state battery could push that share to around 8%, a significant jump in overall costs.

For context, a widely circulated teardown of Tesla's Optimus Gen 2 puts the battery pack at about $300 in a roughly $55,000 hardware cost structure, around 0.5% of the bill of materials, comfortably under 2%, though units with larger packs or lower overall costs would land higher, and some independent estimates, including McKinsey's, put battery modules at 5–10% of a humanoid's bill of materials.

Solid-state cells, with their higher energy density, are one of the most promising routes to a robot that works a human shift without stopping, but given their comparatively steep cost versus the competition, one can understand why SK On is aiming this pitch at the robotics and industrial players that need the technology and can afford to pay for it.

For applications with short duty cycles, swapping a cheap lithium-ion pack or fast-charging between tasks may simply remain the better economic answer, but for customers willing and able to pay for more sustained power, solid-state seems to be the new play, even as it remains elusive for commercial EVs given its cost.

SK On has skin in this game on a specific timeline. The company completed its all-solid-state pilot plant at its Future Technology Institute in Daejeon last September, built in partnership with US solid-electrolyte firm Solid Power.

It is developing two chemistries: a polymer-oxide composite cell targeted for commercialization in 2028 and a sulfide-based cell in 2029, a timeline it has already accelerated by a year. But it has competition waiting in the wings: rival Samsung SDI, working with the same American partner, is aiming for 2027.

Whether this leads to widespread adoption of tech expected to appear only in the most expensive EVs on the market this decade remains to be seen, but the TCO argument Ko makes might stick more easily with industrial customers than with consumer EV buyers, for whom pricing and budgets are key factors.

Via The ELEC