April 26, 2017

Figure 5 Relationship between output of DE and IR for a LIB-submarine on patrol.

Anonymous has kindly provided the following figure and description. This is in the context of Anonymous's previous article Submarine electricity discharge & generation using combinations of Diesels, LIBs, LABs & AIP of April 20, 2017.

Figure 5 Relationship between output of a Diesel generator (DE) and Indiscretion Ratio (IR) during a LIB submarine’s patrol.

The Vertical axis (above) is output of the is in kW.

The Horizontal axis is Indiscretion Ratio (IR) expressed as:

time for snorting /time for snorking + time for operating AIP or batteries) x 100

Power required (PT) is: Propulsion Load (PL= 60kW) and Hotel Load (HL)

Blue, PT=250kW (HL=190kW) based on current submarine; red, PT=300kW(HL=240kW); green, PT=350kW (HL=290kW); violet, PL=400kW(HL=350kW). IR=indiscretion ratio.

With the combat system requiring large amounts of electricity, Lead-acid Batteries (LABs) frequently cannot satisfy the electrical requirement because of its poor capacity. As a result, the capability of  the sonar system of a LAB submarine is inferior to that of an SSN.

In contrast, Lithium-ion Batteries (LIBs) can meet the high electical requirements. Utilising higher kW DEs, LIBs can supply more electricity for the HL, remembering that the PL also requires large amounts of electricity in a large conventional submarine.

If the output of DE is 6000kW within the framework of snorting ability, there is an excellent Indiscretion Ration of 6.25% where expected PL  is 400kW and HL is 350kW..

A well-developed LIB-submarine has the following advantages:
i)        a reduction in indiscretion ratio,
ii)      improvement of high speed performance, and
iii)    enhancement of sensors and processing systems.



MHalblaub said...

Dear Pete,

Power close to 10,000 kW for a Diesel submarine is rather ambitious.

Soryu-class has official 2,900 kW with two Kawasaki 12V 25/25. I'm not sure if 4 Sterling engines at 75 kW are within the 2,900 kW but 4 Sterlings could be a hint for required power for Soryu-class (300 kW or red line in figure 5).

Type 212A or 214 seem to have a requirement of about 240 kW (2 fuel cells at 120 kW - blue line).
Type 212A has one Diesel at 1,050 kW (according to German Wiki and 2,150 to English Wiki). According to this video https://youtu.be/036fCZab13E?t=1m30s I would guess 16 V and therefor 1,850 kW electrical power output (or even less due to venting problems on a submarine).
(Check out this engine MTU 20V 4000 M53B and ratio of bhp to kW)

So with same two generators 3,700 kW electrical output for Type 214.

Collins-class seems to have 3 times 1,400 kW. 4,200 kW electrical power in sum (I assumed it as electrical power output and not as pure diesel power). Violet line?

Drag is proportional related to the frontal surface S.
Beam Type 212/214: 6.8 m / 6.3 m (S = 72.5 m² / 65.5 m²)
Beam Collins-class: 7.8 m (S = 95.5 m²)
Beam Soryu-class: 9.1 m (S = 130 m²)
Beam Suffren-class: 8.8 m ( S = 121.5 m²)
Beam Type 216: 8.1 m (S = 103 m²)

Collins class has about 30 % more frontal surface than Type 212A or 45 % compared to Type 214. Frontal surface is directly related to propulsion load. Therefore adding bigger and more powerful engines can also lead to higher propulsion loads.

It is rather interesting where a Type 214 with less than 250 kW required and 3,700 kW already is: Indiscretion ratio of less than 7 % according to Figure 5.

With a C-rate of 0.2 the battery capacity has to be 3,700 kW x 5 hours or 18.5 MWh. A lead acid battery can store about 30 Wh/kg. A 620 t LAB would be required.
With a C-rate of 0.5 the battery capacity has to be 3,700 kW x 2 hours or 7.4 MWh. A lithium ion battery can store about 125 Wh/kg. A 60 t LIB would be required.

Therefor a Type 214 with LIBs would make sense today.

I missed to implement the efficiency of energy storage due to different type of batteries. LAB are about 70 % and LIB around 90 %.


Anonymous said...

Hi Pete

Rated output of Stirling generator for Soryu is 60 kW, and output of 75W is impossible.

As high C-rate charge/discharge shortens life of LAB, usual output of diesel genetors may be 50% of maximum output.
Aso, depth of discharge (DOD) affects lives of LAB which are more than1000cycles and 400–500 cycles at DOD of 30% and 50%, respecively.

Once a certain years, all LABs in J-submarine are exchanged. The exchange is expensive (1.5 billion yen) and reduces operation efficiency of submarine. Exchange cycle of LIB is expected longer than that of LAB, but, exchange is 6-7 times more expensive (10 billion yen!) than LAB. So charge/discharge frequency of LIBs is smaller than LABs.

In the case of ITO-LIB, exchange cycle is better than 1/30years.


MHalblaub said...

Dear Anonymous,

It is always hard to guess what information is given: bhp for Diesel engine or power output for generator. So the 75 W for the SAAB-Kockums Sterling engine may be bhp while the 60 W are the electrical power output. That is quite interesting.

So two Sterling engines are required to replace one Siemens FCM 120 fuel cell.
FCM 120 dimensions:
H = 50 cm
W = 53 cm
L = 176 cm
Volume: 0.47 m³
Weight (without module electronics): 900 kg

According on this picture http://saab.com/naval/Submarines-and-Warships/technologies/The-Stirling-Engine/
two Sterling engines need at least 4 times more space.
Weight is hard to estimate.

I know that a Sterling engine does not need Hydrogen or Methanol but that is stored outside and not within the pressure hull.


MHalblaub said...

Dear Anoymous,
your comment about the Type 212A just having one battery section might be wrong.

Here a picture of Type 214, Type 212A and Type 209 together:
On top the two battery sections of a Type 214 and the two sections for Typ 209 at the bottom are clearly visible but for Type 212A the batteries are hard to see.

A better resolution for Type 212A:
A battery compartment could be slightly visible right above the "4" but there is also space beneath the engine compartment not as good visible.

The follwing two pictures show that there is space for a battery section in front beneath torpedo storage but also below engine section:

The height of these compartment is visible in the following video sequences.

https://youtu.be/nThnmbim3Xg?t=04m44s (bow section)
https://youtu.be/nThnmbim3Xg?t=08m17s (side view bow section)
https://youtu.be/nThnmbim3Xg?t=32m43s (bow section)
https://youtu.be/nThnmbim3Xg?t=36m43s (man holes in stern section)
https://youtu.be/brHf9jex-mo?t=11m40s (another view of stern section)
https://youtu.be/nThnmbim3Xg?t=45m42s (old Diesel inside a tug boat)
https://youtu.be/nThnmbim3Xg?t=48m15s (loading torpedoes wrapped inside a container)
https://youtu.be/nThnmbim3Xg?t=51m02s (ejection speed of torpedo by water ram is mentioned: 30 km/h)
https://youtu.be/nThnmbim3Xg?t=1h5m11s (smiling bow sonar)

Type 212A may even need batteries beneath the engine compartment to keep the center of gravity at the right place. On the other side the hydrogen and oxygen tanks could be heavy enough.

Finally the 3.5 MWh battery capacity seems to be reasonable due to an engine providing 1.85 MW and a C-rate of 0.5 for fast recharge. This could be sufficient in case required power for an operational Type 212A is maybe well below 100 kW.


Anonymous said...

Hi Pete and MHalblaub

I cancel my comment (28/4/17 8:44 AM), because discussion was insufficient. I am sorry.


Peter Coates said...

Hi Anonymous [29/4/17 8:37 AM]

Thats OK.

It is a complicated subject with only limited information available.



Anonymous said...

Hi Pete

LABs made by Exide Technologies are adopted for many western submarines except Japanese submarines [1, 2]. “Fleet Submarine” provides interesting information on submarine batteries [3]

[1] http://www.naval-technology.com/contractors/electrical/exide-technologies-naval/ (Home Page of Exide Technologies)
Since the 1920s, Exide Technologies Industrial Energy has gained experiences in the development, manufacturing and marketing of their highly reliable submarine batteries. These submarine batteries have been sold worldwide under different brand names (CEAC, Hagen, Sonnak, Tudor), and found application in various classes of submarine, including 205, 206, 209, 212; Dolphin, Scorpene, Walrus, Kobben, Näcken, Västergötland, Gotland, UIa, TR 1700, Agosta, Daphne, Redoutable, Rubis and Triomphant.

[2] https://en.wikipedia.org/wiki/Exide

[3] http://www.fleetsubmarine.com/battery.html (Fleet Submarine, Home / Submarine Technology / Submarine Batteries)


Peter Coates said...

Hi Anonymous [at 11/5/17 9:12 AM]

Its quite remarkable how non-SSK USA is still associated with LABs for submarines.

Looking at https://en.wikipedia.org/wiki/Exide the "Electric Storage Battery Company" (the old name for Exide) has been supplying LABs for subs 119 years ago since USS Holland (SS-1) from 1898.

I wonder if Exide or other US originated company's will start building LIBs for large scale marine applications?

Interesting discussion of backup diesels + battaries + snorkels on US nuclear subs here http://rickcampbellauthor.com/styled/index.html



Anonymous said...

Hi Pete

Large Capacity Lithium Ion Batteries by Exide are ONYX™ [1]. Capacity, dimensions and weight of ONYX™are listed in [2].
Energy densits of ONYX™ are estimated in [3]. Types of lithium ion batteries for ONYX™ are unknown, but there are two types of capacity (ca.120Wh/kg and ca.130kg) [3]. If ONYX™ is successful loaded in J-subamine, energy desnsity of 30-40MWh which is 3-4 fold higher than that of LABs may be achieved. It is not bad for current technology level for LIBs.

Deep insight into and accumated experience are required for development of LIBs for submarine batteries, and Exide well satisfys these conditions.

[1] http://www2.exide.com/my/en/product-solutions/network-power/product/onyx-lithium-power.aspx
[2] http://telcommkt.com/wp-content/uploads/2010/10/Onyx-Lithium.pdf
[3] Calculation of energy density for ONYX™, where Energy density = Voltage x Capacity / Weight.
M70X24V068P (122Wh/kg), M70X48V010P (120Wh/kg), M70X48V024P (131Wh/kg), M70X48V034P (132Wh/kg), M70X48V010N (120Wh/kg), M70X48V024N (131Wh/kg), M70X48V034N (132Wh/kg)
[4] Possibel loading numbers of ONYX™ (M70X48V034N) in Soryu MKI which equips with 480 LAB modules are estimated as follows. Assuming LIB module consists of 10 battery packs where each pack consists of three M70X48V034N, energy density are 38MWh for 4 sets of 20-colunm by 12-raw of 960 LIB-modules.