According to the former Commander of the Japanese Navy Submarines
Service, Vice Admiral (retired) Masao Kobayashi, in a lead-acid battery (LABs) submarine,
one hour-ventilation by using a diesel generator (DG) is needed after battery charging to release hydrogen generated
by the charging process.
Based on this information, the indiscretion ratio of the
five following submarine Cases/scenarios have been reviewed and very roughly
estimated for Japanese submarine missions of 70 days. This is where the surveillance
period is 50 days and transiting period is 10 days x 2 = 20 days) and the DG output
(hotel load + propulsion) is 250kW:
The lower the Indiscretion Ratio (IR) (the snorkeling period per 24 hours) the better.
Case I (submarine length 84m, LABs, powered 100MW (or is that 100 kW?) - air independent
propulsion (AIP), 2 x
2MW-generators, model Soryu
MK I, IR =7%;
Case II (length 84m, lithium-ion batteries (LIBs), 2 x 2MW-generators, model Soryu MK II)
see Table below) IR=6%;
Case III (long range Soryu proposed for Australian Future
Submarine (AFS), length 90m, LIBs,
4
x 2MW-gnerators) IR=2.5%;
Case IV (AFS, length
96m, 100MW-AIP, LIBs, 4 x 2MW-gnerators) IR=2%;
Case V (AFS, length
96m, 100MW-AIP, LABs, 4 x 1MW-generators) IR=7%.
Comparison of Cases I and V shows that IR is determined by
slow charge rate of LABs in a LAB-submarine. Comparison of Cases II, III an IV shows
that output of the DG shows critical effects on IR for LIB submarines.
Performance at low speed means IR is Case IV>= Case III
>>Case II >Case V = Case I.
Performance at high speed, which depends on batteries, is
Case III>= Case IV >>Case II >Case V = Case I.
The facts that:
- using up stored liquid oxygen (LOx) ends the usefulness of
the Soryu’s Stirling AIP, and
- LIBs are better than LABs
shows the flexibility of operation of each cases: Case
III>= Case II >Case IV> Case V=Case I.
The superiority of AIP and LIBs, or simple LIBs, depends on a
submarine’s mission. DGs play a critical role in both LIBs-submarines (Cases II
and IV) within certain diesel power output ranges.
Anonymous thinks the future of LABs-submarines (Cases I, III
and V) are limited with or without AIP and recent the tragedy of Argentina’s ARA
San Juan shows LABs
are not automatically safe.
More mathatically IR was very roughly
estimated as follows:
Over 24 hours the balance of energy supplied [Es] to batteries and energy consumed [Ec] form batteries and AIP is described
in equation (1)
(1) Es = Ec
(2) Es = Energy from
diesel generator [Ed] + Energy from AIP [Ea]
(3) Ec = Energy for
propulsion [Ep] + Energy for hotel load [Eh]
The Indiscretion
ratio (IR) which is the snorkeling period [ts]
per day (=24h) is described in eq (4)
(4) IR = ts/24 x 100
(%) = (tg + th)/24 x 100 (%)
(5) ts = snorkeling period for diesel
generation [tg] + snorkeling period for hydrogen release [th]
This is where, th =1h
for LABs with hydrogen generation, and th = 0h for LIBs without
hydrogen
generation.
Charge of batteries (capacity X (MWh)) with Y of C rate, Ed
for ts is described in (6)
(6) Ed = 1000XYtg This where C daily energy from Z (MWh)-AIP for 50 days-opertion is
described in (7)
(7) Ea =1000Z/50
=20Z
(8) is derived from (2), (6) and (7), Es =1000XYtg + 20Z
(9) If 250 kW of
energy is consumed in an hour, then, Ec = 250 x {24-(tg + th)} ---
(10) is derived from (1), (8) and (9), 1000XY tg+ 20Z = 250
x {24-(tg + th)}
(11) is derived from (4) and (10), IR =[1-{(1000XY tg+
20Z)/(250x24)}]x100=(tg + th)/24 x100 .
Where, tg = (250 x24-20Z-250 th)/(1000XY+250) IR is from eq (11)
10MWh-LAB, non-AIP, 0.2 C rate, 2MW-diesel: X=10, Y=0.2,
Z=0, th =1, IR=14.8%
10MWh-LAB, 100MWh-AIP, 0.2 C rate, 2MW-diesel: X=10, Y=0.2,
Z=100, th =1, IR=11.1%
20MWh-LIB, non-AIP, 0.2 C rate, 4MW-diesel: X=20, Y=0.2,
Z=0, th =0, IR=5.8%
20MWh-LIB, non-AIP, 0.4 C rate, 8MW-diesel: X=20, Y=0.4, Z=0,
th =0, IR=3.0%
20MWh-LIB, 100MWh-AIP, 0.2 C rate, 4MW-diesel: X=20, Y=0.2,
Z=100, th =0, IR=3.9%
20MWh-LIB, 100MWh-AIP, 0.4 C rate, 8MW-diesel: X=20, Y=0.4,
Z=100, th =0, IR=2.0%
ANONYMOS’s CONCLUSION
(LIBs Over LABs)
Though the estimates are based on many assumptions and are rough,
the results clearly show the superiority of LIBs over LABs. Anonymous believes
LIBs are indispensable to maintain the regional superiority of a conventional
submarine.
SS
No.
|
Build No
Name
|
Pennant
No.
|
MoF approved amount ¥
Billions FY |
LABs, LIBs, AIP
|
Laid Down
|
Laun
-ched
|
Commi
ssioned |
Built
By
|
5SS Oyashio
|
8105 Oyashio
|
SS-590/ TS3608
|
¥52.2B FY1993
|
LABs only
|
Jan 1994
|
Oct 1996
|
Mar 1998
|
KHI
|
6SS-15SS
Oyashios
10 subs
|
8106
-8115
various
|
SS-591-600
|
¥52.2B per sub
FY1994-FY2003
|
LABs only
|
15SS Feb
2004
|
15SS
Nov
2006
|
15SS
Mar 2008
|
MHI
&
KHI
|
16SS
Soryu Mk 1
|
8116
Sōryū
|
SS-501
|
¥60B FY2004
|
LABs + AIP
|
Mar 2005
|
Dec 2007
|
Mar
2009
|
MHI
|
17SS
|
8117
Unryū
|
SS-502
|
¥58.7B FY2005
|
LABs + AIP
|
Mar 2006
|
Oct 2008
|
Mar
2010
|
KHI
|
18SS
|
8118
Hakuryū
|
SS-503
|
¥56.2 FY2006
|
LABs + AIP
|
Feb 2007
|
Oct 2009
|
Mar
2011
|
MHI
|
19SS
|
8119
Kenryū
|
SS-504
|
¥53B FY2007
|
LABs + AIP
|
Mar 2008
|
Nov 2010
|
Mar
2012
|
KHI
|
20SS
|
8120
Zuiryū
|
SS-505
|
¥51B FY2008
|
LABs + AIP
|
Mar 2009
|
Oct 2011
|
Mar
2013
|
MHI
|
No 21SS
|
No 21SS built
| |||||||
22SS
|
8121
Kokuryū
|
SS-506
|
¥52.8B FY2010
|
LABs + AIP
|
Jan 2011
|
Oct 2013
|
Mar
2015
|
KHI
|
23SS
|
8122
Jinryu
|
SS-507
|
¥54.6B FY2011
|
LABs + AIP
|
Feb 2012
|
Oct 2014
|
7 Mar 2016
|
MHI
|
24SS
|
8123
Sekiryū
|
SS-508
|
¥54.7B FY2012
|
LABs + AIP
|
KHI
| |||
25SS
|
8124
|
SS-509
|
¥53.1B FY2013
|
LABs + AIP
|
22 Oct 2013
|
12 Oct 2016
|
Mar? 2018
|
MHI
|
26SS
|
8125
Shoryu |
SS-510
|
LABs + AIP
|
2014
|
6 Nov 2017
|
Mar 2019?
|
KHI
| |
27SS First
Soryu Mk 2
|
8126
|
SS-511
|
LIBs only
|
2015
|
2018?
|
Mar
2020
|
MHI
| |
28SS Second
Soryu Mark 2
|
8127
|
SS-512
|
¥63.6B FY2016
|
LIBs only
|
2016?
|
2018?
|
Mar 2021?
|
KHI
|
29SS First Soryu Mk 3
(1) (3)
|
8128
|
?
|
¥76B FY2017
|
LIBs only
|
?
|
?
|
2023?
|
MHI?
|
30SS Second Soryu Mk 3 (2)
|
8029?
|
?
|
¥71.5B FY2018
|
LIBs only
|
?
|
?
|
2024?
|
KHI?
|
Table from information exclusively provided to Submarine Matters. LABs = lead-acid batteries, AIP = air independent propulsion, LIBs = lithium-ion batteries. ¥***B = Billion Yen. MHI = Mitsubishi Heavy Industries, KHI = Kawasaki Shipbuilding Corporation of Kawasaki Heavy Industries.
---
By Anonymous
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