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745-680-B10-001 Rev. A

12

1.0 

Introduction, continued 

1.1 Theory of Operation, continued 

Special seperation system

The oxygen created at the positive plate is absorbed by a special felt seperator and 

prevented to escape from the distance between the plates. Displacement of electrolyte 

by oxygen boubles occur within the seperator and reach the surface of the negative plate 

causing the following reaction: 

Chemically:

2Cd + O2+ 2H2O → 2Cd(OH)2

This reaction chemically discharges a certain amount of cadmium to cadmium 

hydroxide. The current going through the battery recharges this material. 

Electrochemically:

O2+ 2H2O+ 4e → 4OH

This reaction consumes the current directly; that is, hydrogen evolution at the 

negative plate is prevented since the preferred reaction is oxygen recombination.

Special venting system

 

The battery cells are equipped with a low pressure flame arresting vent which operates as 

a one way valve and allows to escape hydrogen and non-recombined oxygen and fixes the 

internal pressure at 0.2 bar.

Porous disc

Pressure rubber

Plastic particles

Sealing ring

Fig. 3, Battery Vent

Fig. 4, Exploded view, Battery vent

Summary of Contents for Lomain

Page 1: ...Alpha Lomain Ni Cd Pocket Plate Battery Technical Manual Effective July 2009 Alpha Technologies ...

Page 2: ...Power Alpha Technologies ...

Page 3: ...r any damage or injury involving its enclosures power supplies generators batteries or other hardware if used or operated in any manner or subject to any condition not consistent with its intended purpose or is installed or operated in an unapproved manner or improperly maintained Photographs contained in this manual are for illustrative purposes only These photographs may not match your installat...

Page 4: ...atteries 16 4 0 Operating Features 17 4 1 Capacity 17 4 2 Cell voltage 17 4 3 Internal resistance 17 4 4 Impact of temperature on cell performance and available capacity 18 4 5 Impact of temperature on lifetime 19 4 6 Short circuit values 19 4 7 Open circuit loss 19 4 8 Cycling 20 4 9 Topping up interval 21 5 0 Sizing the batteries for standby applications 22 5 1 Voltage window 22 5 2 Load profile...

Page 5: ...aller Capacity Batteries 13 Fig 6 Larger Capacity Batteries 13 Fig 7 Terminal cross section 14 Fig 8 Electrode Strip 14 Fig 9 Strips connected 15 Fig 10 NiCd vs Lead Acid performance as a function of temperature 18 Fig 11 Discharge curve of 45A x 4 KGL225P post 2224h Float Charge 50 C 18 Fig 12 Battery life at higher temperatures as percentage of 25 C lifetime 19 Fig 13 Cycle life vs depth of disc...

Page 6: ...ation of this product the following symbols have been placed throughout this manual Where these symbols appear use extra care and attention The use of ATTENTION indicates specific regulatory code requirements that may affect the placement of equipment and or installation procedures ATTENTION A NOTE provide additional information to help complete a specific task or procedure NOTE The use of CAUTION...

Page 7: ... which provides backup power contains dangerous voltages Only qualified personnel should inspect service or replace batteries If batteries are being stored prior to installation charge at least once every six 6 months to ensure optimum performance and maximum battery service life Reduce the chance of spark and wear on the connectors always switch the inverter s battery circuit breaker off before c...

Page 8: ...NiCd batteries Do not place electrically conductive objects e g tools on the battery as this is a short circuit and fire hazard Do not wear rings metal bracelets watches or jewelry when working with the batteries and battery systems Provide sufficient ventilation e g open the doors of the battery cabinet during charging so any accumulated gases can escape The charging gases from batteries are expl...

Page 9: ...the Alpha Lomain Ni Cd pocket plate battery include the following Very good high power rating Low internal resistance Reduced loss of capacity at deep temperature No ice formation at temperatures below 0 C Long lifetime at high temperatures Resistant to the affects of repeated deep discharges Long shelf life No electrolyte stratification Robust construction makes the battery well suited for use in...

Page 10: ...nimizes carbonate formation 3 Electrode Edge connected to pole bolt via hardware for high mechanical stability 4 Horizontal pockets formed by perforated steel strips containing the active material 5 Electrode frame Comprised of electrode edge and side bars Seals the plates and serves as a current collector 6 Fiber mat separator special separator insulates the plates and improves the internal recom...

Page 11: ... charging a Ni Cd battery oxygen evolution occurs just before the positive plate reaches its fully state of charge and reaches its peak if it becomes fully charged Since the negative plate provides a much better charge acceptance than the positive plate hydrogen is not evolved until it has reached its fully charged state In order to reduce the water consumption Alpha Lomain concept has been develo...

Page 12: ...lly discharges a certain amount of cadmium to cadmium hydroxide The current going through the battery recharges this material Electrochemically O2 2H2O 4e 4OH This reaction consumes the current directly that is hydrogen evolution at the negative plate is prevented since the preferred reaction is oxygen recombination Special venting system The battery cells are equipped with a low pressure flame ar...

Page 13: ...tic to prevent leakage of the cell casing and the seams welded or glued of the cell cases and the lids are above the electrolyte level The single cell design completely eliminates the risk of faulty welded seams on the sides and on the bottom of the cell cases This design enhances system economy as it enables the service personnel to replace only the defective cell s 3 Fig 5 Smaller Capacity Batte...

Page 14: ...l is composed of the positive plates containing nickel hydroxide and the negative plates containing cadmium hydroxide Individual pockets are formed from a nickel plated and perforated steel tape pocket tape and house strips of the active material 1 0 Introduction continued 1 2 Safety terminal Tha Alpha Lomain battery features a specially developed terminal design with a redundant leak protection t...

Page 15: ...rial as well as the risk of structural damage Also this design allows for the control of soft short circuits 1 5 Electrolyte The electrolyte used in the Ni Cd batteries is a solution of potassium hydroxide and lithium hydroxide that is optimized to give the best combination of performance energy efficiency and a wide temperature range of use It is an important property of the battery and indeed al...

Page 16: ...n cell type is used for low rates of discharge over long periods where the current is relatively low in comparison with the total stored energy The discharges can generally be infrequent and the recommend discharge time for the KGL P range is 1 hour to 100 hours LOMAIN KGM P The KGM P type battery is designed for mixed loads that include a mixture of high and low rates of discharge It is used for ...

Page 17: ...als of the Nickel and the Cadmium active materials in the Potassium hydroxide electrolyte Therefore the nominal voltage for this electrochemical couple is 1 2 V From the electrochemistry of the reaction given above the free voltage of 1 3 V is given for the Ni Cd cell This voltage is also observed directly after charging of the cell 4 3 Internal resistance The internal resistance of a Ni Cd cell i...

Page 18: ...normal temperatures Lomain next generation batteries offer improved values especially at high temperature applications The effects of low temperature operation increase with higher rates of discharge The values which have to be taken into account can be found in the following graph Lomain next generation batteries passed a long term temperature test at constant 50 C surrounding temperature followe...

Page 19: ...ry for high temperature applications 4 6 Short circuit values The short circuit values of a Alpha Lomain Ni Cd pocket plate battery are unique to each cell range Contact your dealer for specific information 4 7 Open circuit loss The state of charge of a cell on open circuit slowly decreases due to its self discharge This decrease is quite rapid during the first two weeks and then stabilizes at abo...

Page 20: ...s the depth of discharge A battery that is less deeply discharged will provide more charge discharge cycles until it reaches the point at which it can no longer provide the minimum design limit Conversely a battery that has been more deeply discharged will have a shorter charge discharge cycle life The graph below illustrates typical values for the effect of depth of discharge on the available cha...

Page 21: ...recharged on a regular basis In theory the quantity of water used can be found by Faraday s equation that each ampere hour of overcharge breaks down 0 336 cm3 of water Depending upon the operating temperature of the battery and the charging conditions the Alpha Lomain battery has a recombination rate of 90 Calculation of topping up interval for KGL 1390 A cell KGL 1390P is floated at 1 41 V cell T...

Page 22: ...rical performance required by the system from the battery for the particular application It can be expressed in terms of amperes for certain duration or in watts for certain duration The requirements might vary for example from just one discharge to multiple discharge of a complex nature In order to calculate the appropriated battery size please take into consideration point 5 1 voltage window 5 3...

Page 23: ...cing the performance and autonomy of the battery Therefore it is necessary to take this effect into consideration when sizing a Lomain Ni Cd battery The calculation program allows this factor to be included into the customers calculation The floating effect is a reversible effect and can only be eliminated by a full discharge charge cycle Please note that it cannot be prevented by just a boost cha...

Page 24: ... that is able to provide a constant voltage charge and a lower floating voltage or single rate floating voltage The two level charger has an high voltage stage to charge the battery properly after a discharge followed by a lower voltage float level charge This results in a quick charge of the battery and in relatively low water consumption due to the low level float charge Two level charge Boost c...

Page 25: ...ity of 5 x KGL 665P after 15 room hours charging at 1 43 V pc at 30 C room temperature temperature Fig 14 Available 5 hour capacity of 5 x KGM 140P after 15 hours charging at 1 43 V pc at 30 C Fig 15 Total Discharge time 4 43h 94 of nominal capacity Fig 17 Total Discharge time 4 15h 85 of nominal capacity Fig 16 Available 5 hour capacity of 5 x KGL 665P after 15 hours charging at 1 43 V pc at 30 C...

Page 26: ...f water and reducing the current could lead to an insufficient charging For standby application it is normally not necessary to compensate the charging voltage with the temperature In order to reduce the water consumption it is recommended to compensate it at elevated temperature as for example from 35 C on by use of the negative temperature coefficient of 3mV K and cell For operation at low tempe...

Page 27: ...ction 5 3 Ambient temperature Lomain cells stored more than 6 months and up to 1 year A commissioning charge of 15 hours at 0 1 It A is necessary During the charge the temperature should be observed see Section 5 3 Ambient temperature 7 2 Commissioning with constant voltage If the charger s maximum voltage setting is to low to supply constant current charging divide the battery into two parts to b...

Page 28: ...n grease Do not coat any plastic part of the battery e g the cell cases Check the charging voltage If a battery is parallel connected it is important that the recommended charging voltage remains unchanged The charging current in the strings should also be checked to ensure it is equal These checks has to be carried out once a year High water consumption of the battery is usually caused by imprope...

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