Chinese military submarines may soon get lithium-ion batteries – Business Insider | CarTailz

  • Chinese researchers say lithium-ion batteries could improve submarine survivability and combat capabilities.
  • Solutions to battery problems have been found by working in the booming electric car market, the study says.

China’s large fleet of conventional submarines could soon be powered by lithium-ion batteries due to advances in the country’s world-leading electric car industry, according to a study by the Chinese Navy.

A lithium power source — instead of lead-acid batteries — could more than double the time a submarine can spend underwater, give it Tesla-style acceleration and free up space for weapons, Naval Submarine researchers said Academy in Qingdao, Shandong Province.

The changes could significantly improve a submarine’s survivability and combat capabilities, according to an article published Oct. 15 in China’s peer-reviewed journal Marine Electric and Electronic Engineering.

The Navy had concerns about replacing batteries in the submarine fleet with lithium batteries, particularly that they could catch fire or explode. However, according to the study, technical solutions have been found through extensive development and testing in the Chinese electric car market – and lithium batteries have proven safe in difficult situations.

“After solving these problems, the replacement of lead-acid batteries with lithium batteries in conventional submarines is just around the corner,” said the team led by Wang Feng, a submarine designer at the academy.

With an estimated 60 to 70 ships, China has the largest conventional submarine fleet in the world.

A Chinese submarine takes part in an offshore blockade exercise

A Chinese submarine.

Zha Chunming/Xinhua/Associated Press



Conventional submarines use diesel engines on the surface, but when submerged the propulsion system and other equipment draw power from a battery. On battery power, they make less noise than a nuclear submarine, which must use large, powerful pumps to cool the reactor.

All US Navy submarines are nuclear-powered, and there have reportedly been instances where modern conventional submarines have gone undetected until they came dangerously close.

The main purpose of China’s conventional submarine fleet is to protect its coastal areas and strategic waters, including the Taiwan Strait and the South China Sea.

But the lead-acid batteries in those submarines, which have changed little since World War II, were problematic, according to the paper, which cited low energy storage capacity, slow charging, poor power output, short lifespan and toxic gas leaks.

The Chinese military has been planning to replace lead-acid batteries with lithium technology in its conventional submarine fleet for more than a decade.

In theory, lithium can store five times or more electricity than lead and charges or discharges much faster. But accidents – including exploding smartphone batteries – have raised concerns about the safety of the technology.

Lithium Ion Batteries

Lithium Ion Batteries.

Regis Duvignau/Reuters



These accidents were caused in part by nickel and cobalt, elements added to increase battery performance, and in recent years some Chinese battery manufacturers have replaced them with iron and phosphate.

Inexpensive and widely available, iron and phosphate can form highly stable structures that greatly improve the safety of lithium batteries without causing a large drop in performance. In the Chinese market, the number of new electric cars with iron phosphate technology has now surpassed those with nickel and cobalt, according to industry data.

China is heavily dependent on other countries for supplies of nickel and cobalt, so submarines with lithium batteries would most likely use the iron phosphate approach, according to Wang’s team, who could not be reached for comment.

They said other new and proven technologies – including hard carbon and a ceramic coating for battery cell packaging – would also be used on the subs to improve safety.

China produces three quarters of the world’s electric car batteries. “Large-capacity lithium-ion batteries for electric cars have been successfully developed and their performance is world-leading,” the researchers said in the paper.

Japanese Navy JMSDF submarine Oryu Soryu

The Japanese submarine Oryu at its launch in October 2018.


JMSDF/Twitter



The booming market for electric cars has also brought about changes in the defense industry.

“Lithium-ion batteries are widely used in aerospace and defense applications, including individual soldier systems, Army combat vehicles, military communications equipment, the Navy’s mini-submarines and underwater vehicles, and the Air Force’s unmanned reconnaissance aircraft,” he said Wang in the newspaper.

China isn’t the only country looking to equip its submarines with lithium batteries. The Japanese Navy was the first to do so in 2018, adding the metal manganese to the submarine’s lithium battery to improve safety, but at the expense of performance.

South Korea launched its first lithium-powered submarine using nickel and cobalt in 2021. The battery was technically the same as that used in smartphones, but the South Korean military said it built in more protections to ensure safe operation at sea.

Germany and France have also developed prototype lithium batteries for submarine use with plans for military service in the near future.

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