Provides Good Reliability and Keeps Me Out of Trouble (or) Why All Cells are Not Created Equal

Transcription

1 Selecting a Stationary Battery that Provides Good Reliability and Keeps Me Out of Trouble (or) Why All Cells are Not Created Equal A Short Battery Seminar presented by Chris Searles National Director of Marketing, Sales and Business Development BAE Batteries USA

2 What is a Stationary Battery? Properties A Dose of Physics A Mixture of Chemistry A Bit of Metallurgy And a Whole Lot of Electricity All this resides in a container (or jar) or series of jars All this resides in a container (or jar) or series of jars connected to a power supply of some sort [rectifier or charger] and a load.

3 Functionality Stationary ti Batteries serve two (2) primary functions: 1. Provide Back-Up or Standby Power in case of a primary power failure. 2. Provide Reserve Power [Energy Storage] for on-demand applications.

4 Stationary Battery Types Lead Acid Ni-Cad Possible New Alternativesti Lithium [Several Varieties] NAS [Sodium Sulfate] Flywheels Supercapacitors However today we will focus on the conventional lead-acid battery [used in Utility/Telecom/Critical UPS applications]

5 Let s Take a Quick Look At The Evolution of Grid Types

6 The Types of Grids Used with Lead Acid Batteries Pure Lead Manchex Lead d Antimony Lead Calcium Lead Selenium

7 Let s Examine the Advantages/Disadvantages of each Grid Type

8 Grid Alloys Pure Lead Advantages Long Service Life Disadvantages Low Power Density Handles High Temperature Limited it current throughputs Not affected by Soft metal Overcharges

9 Grid Alloys Lead Antimony Advantages Disadvantages Excellent hardening agent Migration of Antimony + - Better grid density Good current conductivity Resistant to damage from discharge/recharge cycles Thus, excellent cycling [good for deep cycle applications] Increase in float current [can be dramatic near end of life] Increased water consumption Shortened service life, [especially in float applications] Higher float current prohibits use in VRLA s

10 Grid Alloys Lead Calcium Advantages Low float current Disadvantages Low number of cycles Developed by Bell Labs Manufacturing Issues (1935) Difficulty mixing w/ lead Deposits at grain boundaries Good constant load battery Variances with ICV s [vpc] Good choice for VRLA Platinum salt deposits lock after 8 years

11 Grid Alloys Lead Selenium Advantages Combines best of both Calcium and Antimony Characteristics Disadvantages Self discharge rate is faster than calcium Excellent cycling abilities Recharge necessary every 3-4 months if in storage Tight regulation of the ICV s Predictable low-rise of float current over life Good watering cycles

12 What is a Lead Selenium Battery? It is used in VLA cells only It contains 3% antimony The IEC classifies a lead-selenium low-antimony battery as having 3% antimony It also contains a trace of Selenium Until recently, best known in Europe

13 What Is a Lead Selenium Battery? VLA [Vented Lead Acid or Wet Cell] Lead Selenium vs. Lead Antimony Low Antimony [ 3% per IEC ] Medium Level Antimony [>3-6%] High Level Antimony [>6%] Does it Make a Difference? We believe the answer is YES But why?...

14 Lead Selenium Batteries Let s Take a Look at afewofthe Strategic Advantages of the Lead Selenium/Low Antimony Battery

15 Batteries for Back-Up Power Utilities/Telecom/Critical UPS Major Advantages vs. Other Batteries Performance and Unique Attributes rely on these 5 characteristics: 1. Grid Alloy (s) 2. Post and Post Seal Construction 3. Jar to Cover Seal 4. Manufacturing Processes 5. Material Supplier QA Processes All 5 of these contribute to the performance characteristics of a good battery Let s take a look at the Grid Alloy today.

16 Batteries for Back-Up Power Utilities/Telecom/Critical l /C iti l UPS The Lead Selenium/Low Antimony Advantage. Advantages: Lead Selenium/Low Antimony vs. Lead Calcium <3.0% Antimony still acts as a good hardening agent for lead. (BAE cells contain 1.6% of antimony) It supplies good grid density, conductivity and tensile strength Ugly antimony poisoning [migration] eliminated or reduced Selenium acts as a grain refiner to inhibit positive grid and post corrosion

17 Batteries for Back-Up Power Utilities/Telecom/UPS The Lead Selenium/Low Antimony Advantage. Advantages: Lead Selenium/Low Antimony vs. Lead Calcium Stability under float charge with predictable float current Consistent cell voltages Predictable float current Superior cycling and deep discharge performance Order of Magnitude difference in cycling capability ( cycles vs ) Consistent performance and long-term life at full capacity

18 Float Currents - OPzS [Tubular] & OGi [Flat] Plates 100 Ah IN ma/100a OPzS 2000 FLOA AT CURRENT AT 2,23V I 50 0 FLAT PLATE VLA LEAD SELENIUM TUBULAR PLATE VLA LEAD SELENIUM OPzS 490 OPzS 200 OGi 1520 OGi 800 OGi 480 OPERATIONAL LIFE AT 25 C

19 Uniform & Consistent Individual Cell Voltages [ICV s] expressed as VPC Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Note: this is a representation. Actual individual cell voltages will be within the +/- tolerance as noted in the manufacturer s technical documentation.

20 C10 OPzS IEC CYCLE TEST (Test Data for a BAE OPzS) IEC OPzS 490 Ah Discharge 3h with 84A (app. 75% DOD C4) Recharge 21h with 2.40V, initially 84A OPzS >1500 cycles J i 1999 Dec 1994 Cycles Jun 1999

21 EQUIVALENT LIFE TIMES AT VARIOUS TEMPERATURES Based on the ARRHENIUS Equation Method (Again, based on Accelerated Life Testing for BAE Models) /27.5 yrs (BAE) OPzS life tim me / year rs /22.5 yrs 33.0/21.3 yrs (BAE) OGi (BAE) OPzV years at 20 C years at 25 C years at 30 C years at 35 C related to an activation energy of IEEE float charge at 62,8 C / days

22 Batteries for Back-Up Power Utilities/Telecom/Critical UPS The Lead Selenium/Low Antimony Advantage. Summary: Lead Selenium/Low Antimony vs. Lead Antimony or Lead Calcium Stability under float charge Consistent cell voltages Predictable float current Superior cycling and deep discharge performance Order of Magnitude difference in cycling capability ( cycles vs ) Consistent performance and long-term life at full capacity One Caution: Batteries in storage should be recharged every 3 4 months

23 Batteries for Back-Up Power Utilities/Telecom/Critical UPS Why Are Different Manufacturers providing OPzS or OGi cells? OPzS = Tubular Plate OGi = Flat Plate Originally per German DIN Standards Now rolled into IEC Body

24 A Careful Look at the Tubular Plate Cell Wh t Gi th T b l Pl t C ll It What Gives the Tubular Plate Cell Its Unique Advantages

25 THE MAKEUP OF THE TUBULAR PLATE Expansion of the positive active mass is restricted by the tubes. The tubes consist of woven polyester with high burst strength.

26 VOLUME INCREASE DURING DISCHARGE density mole weight mole volume Pb kg/l g 18.3 cm³ β -PbO kg/l g 25.7 cm³ PbSO kg/l g 48.2 cm³ 48.2 / 25.7 = / 18.3 = 2.63 PbO 2 PbSO 4 Pb

27 CONSEQUENCES OF VOLUME INCREASE OF THE POSITIVE PLATE Expansion of the active material 1. Reduces the connection between grid and pos. mass (PCL1) Critical connection between lead and lead dioxide: A Pb O barrier has to be avoided. 2. Reduces the connection between pos. mass particles (PCL 2) PCL. Premature capacity loss

28 Two Processes for Filling Tubular Plates 1. Wet Filling 2. Dry Filling is the better method Let s see why!

29 Advantages of Dry Filling 1. When a manufacturer uses a Red Lead Oxide Powder which is >98% pure virgin i lead all imperfections are absent. [We use recycled lead for motive and automotive batteries] 2. Wet filling does not usually use this high percent grade of Lead Oxide; therefore, in most cases, a higher specific gravity is used to compensate for capacity which contributes to a shorter battery life. 3. When a manufacturer uses a dry-filled, controlled vibration process, this ensures that each tube is filled completely, uniformly and packed evenly. Wet filling uses a pressure system that packs the Lead Oxide tight with an increased likelihood of forming cracks in the gauntlet. 4. When a manufacturer uses a polyester woven gauntlet for their stationary batteries these gauntlets will have a much higher burst resistance than fiber gauntlets. UNIQUE ADVANTAGE RESTATED: During the expansion/contraction of the lead during discharge/recharge, the gauntlet holds the active material tight against the lead less or no shedding; maintains full capacity over service life.

30 TUBULAR PLATE CELLS (Cont d) Corrosion- Resistant Lead Selenium Grid and Woven Polyester Gauntlet Filled Tubes with Grid, and Unfilled Tubes

31 TUBULAR PLATE CELLS (Cont d) Filling station of tubular plate manufacturing Tubes are filled and capped, then, each plate is weighed

32 Now A Careful Look at the Flat Plate Cell What About the Flat-Plate Cell Does It Provide Any Unique Advantages

33 TANK Formation of Positive and Negative Plates A very few manufacturers tank form their plates vs. jar formation of individual cells. Note: TANK FORMING ensures consistent quality of all plates [versus jar forming where each jar is cured unto itself].

34 BAE FLAT PLATE GRID DESIGN from Dr. Rusch paper [see catalog]

35 This Poses a Question when it Comes to Lead- Selenium Batteries Which is better to use in my Application

36 Batteries for Back-Up Power Utility/Telecom/UPS Tubular [OPzS] vs. Flat Plate [OGi] Tubular (OPzS) [excellent for telecom & power generation] While it s Long Duration Battery rates are excellent, it s 1-min rates compare favorably w/ General Purpose Lead-Calcium cells [Excellent for Float Applications w/ >1hr -100 hr duration] Web Sock aids compression Flat Plate (OGi) [excellent for UPS & Switchgear] Very Good General Purpose Battery [High 1-min, 15-min &1-hour rates] Good Long Duration Rates in the lower Ah sizes [C8/C10 rates are good as well]

37 Batteries for Back-Up Power Utility/Telecom/UPS Discharge Rate Comparison [200Ah to 1.75 vpc] Min 1Hr 3 Hr 8Hr 12hr Model B OPzS Model B OGi Model E Calcium Model C Calcium Amps Time Model B OPzS Model B OGi Model E Calcium Model C Calcium

38 Batteries for Back-Up Power Utility/Telecom/UPS Discharge Rate Comparison [to 1.75 vpc] Amps Hr Min Hr Hr Hr Model B OPzS Model B OGi Model G (1220) Model L (1200) Model B OPzS 1200 Model B OGi 1200 Model G (1220) Model L (1200) Time

39 A Quick Word About Post and Post-Seal Construction Aren t Leaking Cells and Cracked Jar Covers a Fairly Common Problem

40 BAE POST/BUSHING Panzer Type Pole Rugged construction Rubber rings allow sliding [100% acid tight] Special Manufacturing Process Machined lead pole with brass insert Injection molded ABS plastic Red primer for good adhesion Notches act as barrier dams to limit acid creep

41 Some Cautionary Notes Does Receiving and Installation Procedures really have an Impact on Service Life

42 A Word About Installation t 1. Biggest problem occurs w/ shipping 1) Check for damage at receiving 2) Must report concealed damage w/i 48 hrs for FOB Destination shipments 3) Unfortunately, it is the users cost after that point 2. Checklist against manufacturer s instructions 1) Recommend voltage, S. G. and temperature recording 2) Check torque settings w/ calibrated torque wrench 3) Baseline ohmic measurement testingti

43 A Word About Maintenance 1. We recommend following IEEE 450 Guidelines and the manufacturer s operations and maintenance manual as priority. 2. With NERC requirements now entering the picture (for electric utilities), the issue is consistency, true reliability and ensuring compliance. 3. The only way to determine true capacity is thru capacity testing ti IEEE 450 1) Performance testing 2) Service testing (based on actual duty cycle) 3) Modified performance testing 4. A brief word about Battery Monitoring

44 In Summary... ALL CELLS ARE NOT CREATED EQUAL!

45 All Cells are Not Created Equal Thank You Very Much for your Time and Attention Chris Searles BAE Batteries USA