According to media reports, the Japanese conventional submarine Akira Long was launched recently, which is the first submarine to use lithium batteries. The analysis points out that the submarine will greatly enhance the underwater combat effectiveness of Japan Maritime Self-Defense Force after its future service. More importantly, after the use of lithium batteries, the submarine's underwater diving time will be greatly enhanced. We know that conventional submarines use fuel cells, while Phoenix uses lithium batteries. According to the introduction, the biggest difference between fuel cells and storage batteries is that fuel cells can not store electricity, and the required energy is directly obtained from the fuel, just like a "power plant". Unlike lithium batteries, it is like a "reserve electric power", which can store electricity directly. Lithium batteries are more environmentally friendly than fuel cells.
Although lithium battery has more advantages than fuel cell, its manufacturing technology is very difficult to make. Fuel cells do not require much restriction and cost is very low. Lithium batteries, however, are absorbed by electricity and released by electric redox reactions between metals. And the chemical activity of lithium metal is very strong, and it is easy to react with the surrounding metal. Therefore, its preservation and use require too much for the surrounding environment and use too much. The consequent cost will be higher. At present, only a small number of electronic devices will use lithium batteries. So Japan's use of lithium batteries in submarines is not a big deal, but a new technology, but it also brings risks.