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COMMENT ON LITHIUM-ION BATTERIES (LIBS)
The Japanese Government and private industry have been methodically analysing the performance of Lithium-ion Batteries (LIBs) intended for use in submarines for more than a decade. LIBs may be the technology area that Japan has the greatest lead over its French (DCNS) and German (TKMS-HDW) competitors.
It appears that recent performance data on LIBs for submarine are kept very confidential by all 3 countries, on commercial and national security grounds. This makes it very difficult to ascertain whether any of the 3 have superior LIBs.
The US may also be developing LIBs that may be useful for submarine use. It is unknown whether the US Government (and US private industry) would exchange more LIB technical information with the US’s Pacific ally, Japan, or its NATO allies, Germany and France.
S’s TRANSLATION OF A JAPANESE DOCUMENT
“FY2006 Policy Evaluation Report (Result of Policy Implementation)” by Department of Finance & Equipment from Oct/2006 to Mar/2007
Project Name: Research on new main batteries for submarine
Policy System: I-4-(2)-2 Research (Development)
Abstract:
We studied high performance main batteries as main batteries for next submarine, which is alternative of current lead acid batteries, and got necessary technological data.
Budget: About 4,6 billion yen
Evaluation
1. Aim of Project
Lead acid batteries have drawbacks such as heavy weight, large volume, cumbersome treatment and long charging time. The aims of this project are to study lithium ion batteries with high energy density as main batteries for next submarine, and to demonstrate their feasibility and effectiveness.
2. Status of Achievement
Effect of Achievement
We established technology base of large lithium ion batteries with high capacitance for main batteries of submarine by achieving following technological terms (a-d). We obtained technological data on performance, safety and life of submarine main batteries, which would contribute to enhancement of stealth ability, motion performance and attack avoidance ability, extension of submerging period, and improvement of maintenance
(a) Energy density
By adopting lithium ion batteries, we realized new batteries with twice higher energy density per unit weight volume than that of lead acid batteries.
(b) Charging efficiency
We confirmed that lithium ion batteries showed more efficient charging and lower reduction in capacity at high efficient discharging than lead acid batteries.
(c) Safety
We confirmed that lithium ion batteries ensured designed safety in overcharging, overdischarging and external short circuit situations.
(e) Repeatable numbers of charge and discharge cycle
We confirmed that lithium ion batteries showed 1.5 times larger repeatable numbers of charge and discharge cycle than lead acid batteries, having excellent life time.
(2) Period of Achievement
We started research trial in 2002, finished laboratory testing by 2005.
(3) Profit
In this research, we have tried realization of lithium ion batteries with high capacity considering implementation and established new technology base in a short period.
["S" in Comments [October 12, 2015 at 5:22 PM] indicated (along the lines) that Japanese research on new main batteries for submarine revealed that the energy density of LIBs was twice that of LABs and lifetime of LIBs was 1.5 times that of LABs.
But, from analysis of “Life Cycle Cost (LCC) Management Reports on 23SS (LABs-Soryu) (see Soryu Table) and 27/28SS(LIBs-Soryu)” and other budget papers, S concludes that the life time of current LIBs will be twice that of LABs [that is higher than "1.5 times"] and that prices of LIBs will be high. When adding 24-years of operational life of 22 Japanese submarines with 30-years operational life of the 8 Australian submarines, more than 300,000 LIB unit cells will be needed. There may be a reduction in the price of LIBs caused by mass production effects.]
EXPRESSIONS OF INTEREST "SEA 1000 JAPANESE GOVERNMENT & INDUSTRY"
"According to NDS Z 2 0 0 3 C ( 2 ) (Standards of Ministry of Defence: Non-destructive inspection of war ship steel and classification of its result), following non-destructive inspections are needed for steel; i) magnetic particle inspection, ii) dye penetrant inspection, iii) ultrasonic testing, and iv) radiographic testing. Qualification from level 3 to level 1 is required for each inspector."
For "3. Building" item "02. Welding" Inspection Service" it does not go down to the level of detail on whether Gas Tungsten Arc Welding (GTAW) of pressure hull naval steel NS110 is required.
Some anonymous advice is "the MOD may release a list of subcontractors which is partially disclosed. Translation and understanding of NDS (MOD Standards) are also very important. There are so many things to do."
IMPROVED SNORKEL
The MOD has highlighted some of its research achievements in its "Technical Research & Development Institute, R&D, Department of Development" website at http://www.mod.go.jp/trdi/en/research/gijutu_senpa_en.html . Highlights include Sonar System for Next-Generation Submarines, Heavy Weight Torpedo G-RX6 and Snorkel System for Next-Generation Submarines.
Snorkel System for Next-Generation Submarines shortened as Improved Snorkel comes with this diagram and description:
"In order for our submarines to cope with the future situation properly, we are also developing and implementing the snorkel power generation system which to be smaller size and higher power to make platform more silent and covert." (Photo and text courtesy Japanese Ministry of Defence) --
The most publicised advantage of the Improved Snorkel system for the future Soryu is its ability to operate in typhoons/major storms, often described as higher sea states.
An equally important, though lesser known innovation, is its higher power allowing snorts to be quicker, thus reducing the near surfaced danger period. The ability of LIBs to be charged more quickly than lead-acid batteries is a major advantage. The smaller size of the snorkel should reduce the chances of it being seen visually or by radar.
In Comments [at October 15, 2015 at 12:42 AM] S advised (along the lines) There is very little information on the Improved Snorkel. S estimated air intake velocity for the big snorkel. The diameter is estimated from a picture of snorkel and the statement from the Japanese Navy the “snorkel of the Soryu is as big as a drum”. When that snorkel it operating to two Soryu standard 12V/25/25SB diesel engines the maximum intake velocity at full power operation is very fast (135km/h). Even in gentle rain, but not substantial wave conditions, kilograms of water will be introduced into the snorkel in an hour at a 135km/h intake velocity. The design of the Improved Snorkel system is a critical factor for quick charging the LIBs."
S added "By the way, acoustic stealth performance is not expected in snorkel operation. MAN diesels show 100-115DB of noise, I do not think that new KHI diesel engine will show drastic reduction in noise. Current 12V/25/25SB generates terrible noise in surface operation. Also huge amount of exhaust bubbles from the snorkel generates easy-to-detect noise.”
Comment
A stealthy snorkel system may disperse diesel exhaust better in the water so it is less easily chemically “sniffed” by manned aircraft, UAVs, surface craft or other sensors. Heat/infra-red signature or water disturbance by snorkel, exhaust or snorkel wake may be less. Snorkels can be better camouflaged for night, day and storm use. Snorkels can be better streamlined allowing a submarine to operate on snorkel more quickly through the water. Perhaps a snorkel can be made taller, allowing “snorting” at a deeper-safer depth for the main sail and main hull of the submarine.
Pete
Izumi Ishii, Vice President of Integrated Defence & Space Systems at Mitsubishi Heavy Industries Ltd. during SEA1000 Industry Briefing at PACIFIC 2015
Japan SEA1000 Industry Briefing at PACIFIC 2015
