LG Energy Solution vs. Samsung SDI: The Battle for Hyundai’s Humanoid ‘Atlas’ Battery Contract — A Cell-Form-Factor Perspective

What is in focus: who will take the first major humanoid battery reference?

LG Energy Solution and Samsung SDI are competing for the battery supply contract for Hyundai Motor Group’s next-generation humanoid robot ‘Atlas’. According to industry reports, a supplier decision was originally expected in the first half of the year, but the timeline has slipped, and a final decision is now expected around year-end. This article reads this contest from the perspective of cell form factor (the external size standard of a cell) and examines how the choice of form factor changes the supplier landscape and the scope of patent review.

Start with the industry context. On its product page, Boston Dynamics gives Atlas’s battery runtime as 4 hours and explains that the robot autonomously navigates to a charging station, swaps out its own battery and returns to work. The same page lists a height of 1.9 m, a weight of 90 kg, 56 degrees of freedom and an operating temperature of -20 to 40°C. According to a February 2026 report, Hyundai plans to deploy Atlas at its US plants starting in 2028.

The source of tension is that views on the cell standard diverge. The original article reported that the industry sees a good chance of a 21700 cylindrical cell (21 mm in diameter, 70 mm tall) being used, but an English-language report in January 2026 cited industry sources as saying Atlas is more likely to use 4680-format cylindrical cells than 21700. This article answers three questions. Why are cylindrical cells advantageous in humanoids? How do the two companies’ strengths change depending on whether 21700 or the 46-series is chosen? And which rights should IP staff check first?

Basic principle: laying bricks or raising pillars

From a cell-design standpoint, the interesting angle is form factor. The industry sees a good chance of cylindrical batteries being used, given their space efficiency, high power and design flexibility. Because humanoid robots often need batteries distributed across each joint or a pack crammed into a tight space, the shape freedom of a cylindrical cell can work in its favor over prismatic or pouch formats.

By analogy, a 21700 is a small brick and a 46-series cell (46 mm in diameter) is a thick pillar. Small bricks are easy to stack into a curved chest or narrow gaps, but because there are many of them, connections and management circuitry increase. Thick pillars are fewer in number, so assembly is simpler, but each one takes up more space, reducing layout freedom. In a January 2026 report, an analyst explained that with the 4680 format about 40 cells could fit in the robot’s chest, whereas older formats would require more than 200.

The conditions required of a humanoid battery can be summarized as follows.

• Continuous operation: 4 hours as stated by Boston Dynamics, with a reported battery capacity of 3.7 kWh
• Self-swapping: because the robot swaps its own battery, the reliability of pack-level removal and attachment matters
• Space constraints: the pack must fit in limited spaces such as the chest, so cell count and layout are design variables
• Environmental conditions: operation at -20 to 40°C and an IP67 dust and water protection rating

Comparison: standards and supplier strengths

The table below summarizes the differences between the two cylindrical standards as confirmed from public sources. Cell counts are values reported as analyst estimates.

Item	21700 cylindrical	46-series cylindrical (4680)
Dimensions (mm)	21 diameter × 70 height	46 diameter × 80 height
Cells in Atlas chest (estimate)	More than 200 (older-format basis)	About 40
Existing robot applications	Samsung SDI supplies Hyundai robots ‘DAL-e’ and ‘MobED’	Reports of LG Energy Solution 46-series cells in the CES 2026 Atlas (not officially disclosed)
Design advantage	Small units suit curved surfaces and gaps	Fewer cells simplify connections and assembly
Design burden	More cells add connection and management burden	Larger individual cells reduce layout freedom

What this table says: The 21700 and 46-series were reported to differ by more than fivefold in the number of cells installed in the chest, more than 200 versus about 40. Which standard is adopted is directly linked to whose existing track record becomes the more direct reference.

Item	Samsung SDI	LG Energy Solution
Relationship with Hyundai Motor Group	MOU with Hyundai Motor and Kia to co-develop high-performance robot batteries (2025)	Reports of supplying the CES 2026 Atlas battery (citing industry sources)
Robot supply record	Supplies 21700 cells for Hyundai service robots	Boston Dynamics ‘Spot’ 1.0 and 2.0, Bear Robotics (exclusive supply since 2024), six or more robot customers
Next-generation card	All-solid-state batteries for robots, targeting mass production in H2 2027	Mass-production capability in small cylindrical cells

What this table says: Samsung SDI’s case rests on co-development with Hyundai Motor Group and its 21700 supply record, while LG Energy Solution’s rests on its record supplying Boston Dynamics products and reports of 46-series use. The axes of their strengths span different standards.

Patent perspective: robot patents have no battery, and cell patents have no robot

No patent directly tied to this contract could be identified from published patent information. However, looking at published patents on both humanoids and cylindrical cells makes it possible to read the shape of the rights landscape.

The humanoid side: Figure AI Inc’s US20250269518A1 (“Humanoid robot”, priority date February 26, 2024, published August 28, 2025) claims in claim 1 a torso, an arm, a wrist rotation axis, the degrees of freedom of the fingers and thumb, and the change in angle during wrist motion. The battery is mentioned only in the description, to the effect that reducing the degrees of freedom in the central torso allows a larger battery pack to be included. In other words, the scope of robot patents is concentrated on kinematics, and the battery appears only as ‘space’.

The cell side: Tesla’s US11749842B2 (“Cell with a tabless electrode”, priority date November 5, 2018, granted September 5, 2023) is Active according to Google Patents, with an anticipated expiration of November 4, 2039. Claim 1 claims a configuration in a cylindrical cell in which multiple spaced conductive portions are formed at the end of the electrode substrate and, after winding, are bent to contact the cap in a concentric circular pattern.

Insight: the choice of form factor sets the scope of FTO. The 21700 is a standard format that has been mass-produced for a long time, but if a tabless structure is adopted in a larger-diameter cylindrical cell such as the 46-series, electrode-structure patents such as US11749842B2 come into the scope of review. Because robot patents do not claim cell structure and cell patents do not claim robot use, FTO (freedom-to-operate) review for humanoid batteries is likely to be decided not on the robot side but by the internal-structure patents of the chosen cell standard. The standard decision effectively sets both the supplier selection and the scope of patent review at the same time.

Design-around points: Claim 1 of US11749842B2 requires ‘multiple spaced conductive portions’ that ‘contact the cap in a concentric circular pattern while bent’. A design that forms the conductive portion as one continuous strip, or connects through a separate current-collector plate rather than the cap, may keep a literal distance from this element.

Design-around scenario (counterargument): However, even when going through a separate current-collector plate, if a method that bends the entire electrode edge to contact over a wide surface produces substantially the same function and effect, it could become subject to a doctrine-of-equivalents analysis. In addition, cell makers may each hold their own tabless patents, so the actual likelihood of disputes may depend on whether cross-licenses exist. Ultimately, it can only be judged by comparing the electrode connection structure of the adopted cell with the claims one to one.

Limits and outlook

Beyond the revenue itself, this contract is being viewed as a key reference for establishing an early lead in the humanoid-robot battery market, which is expected to grow. The optimistic outlook is that the first supplier secures the standard cell format at the mass-production stage and carries it through to subsequent robot models.

There is also a contrary scenario. The maker and product name of the battery installed in the CES 2026 Atlas were not officially disclosed, and estimates differ from report to report. Views on the standard itself are also split between 21700 and the 46-series. And since Samsung SDI has set a target of mass-producing all-solid-state batteries for robots in the second half of 2027, if the cell chemistry or standard changes by the time of mass production, the reference value of the first contract may turn out smaller than expected.

The strategic alternative is to prepare designs and rights on the premise of dual-sourcing by standard (for example, separating the cell standard for initial volumes from that for next-generation volumes), even if a single supplier is confirmed. From the robot maker’s standpoint, separating the pack-level self-swap interface from the cell standard allows the mechanical design to be kept even if the cell supplier or standard changes.

Practical action: IP staff planning robot batteries should first check the electrode connection structure for each candidate cell standard (21700 and 46-series), and if a tabless structure is included, prepare a table comparing it with the ‘spaced conductive portions and concentric cap contact’ elements of claim 1 of US11749842B2.

Items requiring verification

• The primary source of reports that supplier selection slipped from the first half to year-end, and Hyundai Motor Group’s official position
• The cell standard (21700 or 46-series) to be adopted for production Atlas units, and the actual battery supplier for the CES 2026 demonstration unit
• The exact signing date of the Samsung SDI-Hyundai Motor-Kia robot battery co-development MOU
• Whether Boston Dynamics has filed patents on the battery self-swap structure
• Whether US20250269518A1 has been granted, and its patent number

Sources

1. Boston Dynamics, Atlas product page
2. The Investor, Behind Hyundai’s Atlas, battery race is taking shape (2026-01-21)
3. Korea JoongAng Daily, Atlas robot powered by LG Energy Solution battery, industry sources say (2026-02-12)
4. Korea Financial Times, report on the robot battery market (2026-02-09)
5. The Korea Economic Daily, Samsung and Hyundai Motor team up to develop batteries dedicated to robots and humanoids (2025-03-31)
6. THE ELEC, Three battery makers compete on robot batteries at InterBattery 2026
7. LG Energy Solution technology blog, 21700: the dark horse of cylindrical batteries (2022-06-09)
8. Google Patents, US11749842B2 – Cell with a tabless electrode (Tesla Inc)
9. Google Patents, US20250269518A1 – Humanoid robot (Figure AI Inc)

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