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Nickel-cadmium block battery

Technical manual

Summary of Contents for SBL

Page 1: ...Nickel cadmium block battery Technical manual...

Page 2: ...lly safe 4 2 13 Low life cycle cost 4 3 Electrochemistry of nickel cadmium batteries 5 4 Construction features of the block battery 6 4 1 Plate assembly 7 4 2 Separation 8 4 3 Electrolyte 8 4 4 Termin...

Page 3: ...technical manuals are available which address the particular characteristics of these ranges 6 7 Cycling 14 6 8 Effect of temperature on lifetime 14 6 9 Water consumption and gas evolution 16 7 Batter...

Page 4: ...nd operating characteristics of the Saft Nife pocket plate block battery to enable a successful battery system to be achieved A battery which while retaining all the advantages arising from nearly 100...

Page 5: ...see section 9 2 Mechanical abuse 2 8 High resistance to electrical abuse The block battery will survive abuse which would destroy a lead acid battery for example overcharging deep discharging and high...

Page 6: ...in the electrochemistry of the process and are naturally corroded during the life of the battery The charge discharge reaction is as follows During discharge the trivalent nickel hydroxide is reduced...

Page 7: ...blocks of 1 10 cells depending on the cell size Plate group bus Connects the plate tabs with the terminal post Plate tabs and terminal post are projection welded to the plate group bus Separating grid...

Page 8: ...ssembly The nickel cadmium cell consists of two groups of plates the positive containing nickel hydroxide and the negative containing cadmium hydroxide The active materials of the Saft Nife pocket pla...

Page 9: ...n the cell plates irrespective of the charge level In most applications the electrolyte will retain its effectiveness for the life of the battery and will never need replacing However under certain co...

Page 10: ...d 4 They can be recognized from the block dimensions as follows Block width mm Block height mm Plate module 123 194 1 123 264 2 195 349 3 195 405 4 Table 1 Correlation between block dimensions and pla...

Page 11: ...e different discharge types The choice is related to the discharge time and the end of discharge voltage There are of course many applications where there are multiple discharges and so the optimum ra...

Page 12: ...cations 5 3 Type H The SBH is designed for applications where there is a demand for a relatively high current over short periods usually less than 30 minutes in duration The applications can have freq...

Page 13: ...sistance of a block battery cell depends on the performance type and at normal temperature has the values given in Table 3 in milliohms per Ah of capacity To obtain the internal resistance of a cell i...

Page 14: ...e for operating temperatures from 30 C to 50 C Figure 1 a Temperature derating factors for H type plate 1 2 1 0 8 0 6 0 4 0 2 40 20 0 20 40 Derating factor special electrolyte required for continuous...

Page 15: ...ncountered in stationary applications This can vary from low depth of discharges to discharges of up to 100 and the number of cycles that the product will be able to provide will depend on the depth o...

Page 16: ...s reduced to less than 1 year if used at 50 C 15 Figure 2 Capacity loss on open circuit stand 100 90 80 70 60 50 0 50 100 150 200 250 300 350 400 Percentage of initial capacity 40 C Open circuit perio...

Page 17: ...f discharge of the electrodes The overcharge current is a function of both voltage and temperature so both have an influence on the consumption of water Figure 5 gives typical water consumption values...

Page 18: ...previous discharge The factors used for this will depend on the depth of discharge the rate of discharge and the charge voltage and current A requirement for a high state of charge does not justify a...

Page 19: ...and so the minimum voltage for the single level and the two level charge voltage is the normally recommended value This also helps within a voltage window to obtain the lowest and most effective end o...

Page 20: ...w than the two rate charger The two rate charger has an initial high voltage stage to charge the battery followed by a lower voltage maintenance charge This allows the battery to be charged quickly an...

Page 21: ...tage 1 50 volts per cell Charge Time hours Charging Voltage 1 40 volts per cell Charging Voltage 1 45 volts per cell Charging Voltage 1 55 volts per cell Current Limit 0 2 C5A Temperature 20 25 C H ty...

Page 22: ...harge times from a fully discharged state for the L block 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0 5 10 15 20 25 30 35 Available Capacity of rated capacity Charging Voltage 1 50 volts per cell C...

Page 23: ...A constant current first charge is preferable and this should be such as to supply 300 of the rated capacity of the cell Thus a 250 Ah cell will require 750 ampere hours input e g 50 amperes for 15 h...

Page 24: ...cid batteries this will lead to failure of the battery and is unacceptable The block battery is designed to make recovery from this situation possible Overcharge In the case of the block battery with...

Page 25: ...0 45 liters of hydrogen 10 Installation and storage 10 1 Batteries on arrival On receiving the battery open the cases and check for any indication of damage in transit Remove the cells and any access...

Page 26: ...0 45 liters of hydrogen 10 Installation and storage 10 1 Batteries on arrival On receiving the battery open the cases and check for any indication of damage in transit Remove the cells and any access...

Page 27: ...of 2 for example the air in the room will need changing 3 2 1 5 times per hour In practice a typical figure for natural room ventilation is about 2 5 air changes per hour and so in this case it would...

Page 28: ...of 2 for example the air in the room will need changing 3 2 1 5 times per hour In practice a typical figure for natural room ventilation is about 2 5 air changes per hour and so in this case it would...

Page 29: ...tery operations the electrolyte will retain its effectiveness for the life of the battery Thus normally it is not necessary to change the electrolyte However under certain battery operating conditions...

Page 30: ...Saft Argentina SA Buenos Aires Tel 54 11 4 686 1994 Fax 54 11 4 686 1925 AUSTRALIA Saft Pty Ltd Seven Hills Tel 61 2 9674 0700 Fax 61 2 9620 9990 BELGIUM NV Safta SA Brussels Tel 32 2 556 44 00 Fax 3...

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