Solid batteries, which use a solid material instead of a liquid to conduct electricity, are still not widely available, but some companies are offering a type called "semi-solid." These are not fully solid but represent a step toward the technology. True solid-state batteries, which are safer and more energy-dense, are still in development. However, recent progress suggests that the goal may finally be within reach. In traditional lithium-ion batteries, a flammable liquid electrolyte allows ions to move between the electrodes, limiting both safety and performance. Solid-state batteries replace this liquid with a solid material, potentially offering higher energy storage and greater safety. ProLogium, a Taiwanese company, now claims it can produce solid-state batteries at scale, not just in the lab. Its latest battery cell has a capacity of 381 Wh/kg—significantly higher than the 250 to 300 Wh/kg of the best lithium-ion batteries available today. These results have been verified by independent organizations, including TÜV in Germany, and the company has also met a new Chinese standard that distinguishes solid-state batteries from semi-solid ones. While the performance in the lab is impressive, the real challenge will be whether these results can be consistently achieved when producing thousands, and eventually millions, of cells at scale. ProLogium has been working on its solid-state battery technology since 2012, and it has already produced cells in small quantities since 2013, initially for consumer electronics before expanding into the automotive sector. The company is now on its fourth generation of battery design and third generation of production line, having delivered over 2.4 million cells. ProLogium emphasizes a strategy of continuous improvement, making only minor adjustments to its production lines with each new battery generation. According to the company, the next generation, Gen 4, would require only 10% modifications to existing lines. ProLogium has secured partnerships with several companies, including an American supplier of audio systems that is equipping cars for a major Japanese manufacturer. The company has also received financial support from Mercedes and has previously worked with Chinese automakers like Nio and Aiways. However, the current production capacity at ProLogium’s Taiwanese plant is relatively small—only about 0.5 GWh per year, enough to power just over 6,000 electric vehicles with medium-sized batteries. This highlights the gap between current production levels and the massive demand from the automotive industry. The true test for ProLogium’s solid-state batteries will come in France, where a potential factory in Dunkirk is being considered. The plan is to reach a production capacity of 4 GWh by 2030, with a long-term goal of up to 44 GWh—nearly 100 times the current capacity of the Taiwanese plant. A North American site is also under consideration, with a phased approach that would initially involve shipping key cell components to local partners for assembly, before moving toward full-scale production if demand grows.