The physics of weight creates a brutal trade-off: add a larger battery and the robot gets heavier, which means it needs more energy just to move itself. This trade-off makes it difficult to extend running time without fundamentally changing how batteries are made.
For now, the batteries we have today show us what a robot is capable of doing. But it’s the batteries of the future that will determine whether they can truly operate as practical everyday assistants for humans.
The limits of today's battery technology
Like those used in smartphones, electric cars, and even submarines, lithium-ion batteries are used in most robots nowadays. They are reliable and cheap, but they have a limit. They can’t store enough energy for a long day of work without becoming too heavy to move efficiently.
While reliable and cost-effective, lithium-ion technology improves only gradually. Energy density has risen over the past decade, but the gains have been incremental rather than transformative. Even incremental improvements, such as silicon-enhanced lithium-ion batteries, now appearing in consumer electronics, offer only modest gains in energy density and do not fundamentally change the limits facing robotics.
More importantly for households, battery longevity is the hidden Achilles’ heel. Like people, batteries age over time, and every charge cycle adds a little more wear. Fast charging can accelerate the aging process further. Eventually, it can no longer complete its assigned tasks without recharging. Many people have felt this pain firsthand: replacing a small smartphone battery is already expensive. Now scale that up to a home robot with a much larger battery pack, and the cost compounds quickly, turning battery replacement into a substantial, and often overlooked, expense.
While researchers are exploring alternatives such as solid-state or sodium-ion batteries, these technologies are not yet ready for mass production. Battery makers are increasingly presenting semi-solid and solid-state designs as the next step in battery development. For robots, however, these technologies are still at an early stage of commercialisation. For the foreseeable future, the useful life of a robot will remain limited by the battery hardware currently available.
As battery technologies evolve, much of the serious momentum is now in East Asia. South Korean firms such as Samsung SDI, Japanese manufacturers such as Toyota and Panasonic, and Chinese battery giants such as CATL are all trying to push beyond the limits of today’s lithium-ion cells.
The most closely watched is solid-state design, which replaces the liquid electrolyte with a solid material. In principle, that can improve safety, raise energy density, and cut charging times.
Samsung SDI, for example, has said its solid-state prototypes have reached 900 watt-hours per litre (Wh/L), around 40% higher energy density than its current cells in mass production. Toyota has said its first solid-state batteries could offer around 20% more range with charging times of 10 minutes or less. China is also pushing alternatives such as sodium-ion chemistry – CATL has reported its first-generation sodium-ion cells can charge to 80% in 15 minutes.
But this is exactly where the gap between headlines and households appears. These technologies are promising, but they are still expensive and difficult to manufacture consistently at scale, and in some cases still struggle with durability over repeated charge cycles. So, the breakthrough is real, but so is the bottleneck. For now, the robot in your home is still limited less by what its software can imagine than by what its battery can deliver.
Story: Dr James Kang – Senior Lecturer in Computer Science & Dr Byron Mason – Senior Lecturer in Robotics and Mechatronics Engineering, RMIT University Vietnam
Thumbnail image: Olena - stock.adobe.com | Masthead image: YanaIskayeva - stock.adobe.com
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A version of this article was first published by Tia Sáng - VnExpress. Read the original article here.
