Basics & Working Principles of Batteries

7/14/2019 Basics & Working Principles of Batteries

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HBL Power Systems Ltd.Welcomes you all

Since 1977


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We dont forget our batteries after you have paid for them.

Our Service Policy

We achieve this through

National Service Network with dedicated customer centric teams

Well equipped centers even at remote locationsTime bound empathetic complaint disposal.

Reliable and cost effective service solutionsImparting customer training

Since 1977


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Since 1977


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Expertise in Battery Technologies

Nickel Cadmium (1.2 V)

Sintered Plate ---- Vented & Sealed

Pocket Plate ---- Vented &Valve Regulated

Fibre Plate

Silver Zinc (1.5 V)

Primary & secondary Lead Acid (2 V)

Valve Regulated Lead Acid (VRLA)

Valve Regulated Lead Acid GEL

Pure Lead-Tin Monoblock (SMF) Tubular Lead Acid (LMLA)

Tubular Lead Acid GEL

Lithium (3.5 V)

Lithium Thionyl & Chloride

Since 1977


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Battery Basics

What is cell or battery?

Cell is a device that converts the chemicalenergy into electrical energy by means of anelectrochemical reaction.

Battery consists of two or more cells electricallyconnected.

In common usage, the terms "battery" and "cell"are used interchangeably.


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Types of Batteries

Primary(Use and throw)

Alkaline . Acid .

Secondary(Rechargeable)

Battery


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Battery Capacity:

Amount of charge available - ampere-hours (Ah).

Depends on 1. Quantity of active materials

2. Amount of electrolyte

3. Surface area of the plates

Measurement:

Terminal voltage under discharge at standard conditions of 27C


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Rated capacity:

Amount of charge available in ampere-hours(Ah) when battery discharged at specified rate.

Example:

Lead-acid battery rated for 200 Ah (for a10-hour rate) will deliver 20 amperes of currentfor 10 hours under standard temperaturecondit ions before its terminal voltage reaches

specified value.Battery capacity varies with the discharge rate.


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Battery connectionsSeries ConnectionPositive terminal connected to the negative terminal increases the overall

voltage but the overal l capacity remains the same.

Parallel ConnectionLike terminals connected together, the overall voltage remains same but

capacity will be increased


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LEAD ACID BATTERY TECHNOLOGY

HBL POWER SYSTEMS LTD


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Tubular Flat plate

Flooded

Lead Calcium Tin

Gel

Tubular

Pure Lead Tin Lead Calcium

AGM

Lead Calcium Tin

Gel

Flat plate

VRLA

Lead Acid batteries

Classif ications of Secondary Lead Acid Batteries


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Components of Lead Acid Battery / CellSince 1977


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Maintenance Free

--

--

-Sediments Bridge

at the bottom Absorbed Electrolyte inSeparator ( AGM)

Envelope Separators

(No Shedding)

Tubular Positive Plate

Maintenance Required Maintenance Free

(Low Maintenance)

Vented

Small Acid abovethe Plates

Vented

Large Free Acidabove the Plates

Acid Starved

Immobilized AcidSmaller Size

PbO2

PbO2

PbO2

Pb

PbPb

+ - +

+

-

-

Conventional Early M F (LM) Valve Regulated wi thAbsorbed Electrolyte

Evolution of MF-Lead Acid BatterySince 1977


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Different types of Plates

Plante Flat grid Tubular


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Plate/Electrode Active material Stores the charge Grid - Electrical conductor & support for active materialDifferent types of plates

Plante plate : Active material has been electrochemicallyproduced over lead sheet

Flat pasted plate : Active material has been supported by

lead alloy mesh

Poor cyclic life

- Better high rate

Tubular plate : The paste is held in micro-porous, non-conductive tubes (gauntlets)

- Better for heavy cycling


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Since 1977


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Alloys

Battery grid is made from a lead alloy

Alloying elements

Antimony - Lead antimony alloy

Calcium - Lead calcium alloy

Tin - Lead tin alloySelenium - Low antimony alloy reduced water loss

Tin is added to lead-calcium positive grids to improve the

i) cycle life

ii) less corrosionPure lead is very soft


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Antimony Vs Calcium

1. Better deep cyclability with antimony

2. More gassing with antimony more water consumption

3. Low self discharge with calcium low float current

4. Positive plate growth with calcium due to grain boundary

corrosion buckling / container rupture


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Since 1977


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VRLA Design

Absorbed electrolyte

Special alloys - minimizes gassing

Gas Recombination Principle

Valve Regulated

High purity metals

Separato

r

+Ve

Plate

-Ve Plate

Since 1977


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Conceptual View - Oxygen Recombination Process


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The reactions involved in the cell:

At the negative electrode

DischargePb + H2SO4 PbSO4 +2H+ + 2e- E = 0.356V

Charge

At the positive electrode

Discharge

PbO2 + 2H+ + H2SO4 +2e

- PbSO4 + 2 H2O E = 1.685V

Charge

Overall Reaction:

DischargePbO2 + Pb + 2 H2SO4 PbSO4 (+ve Plate) + PbSO4 (-ve Plate) + 2 H2O

Charge

E = 2.041V


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Acid Specific Gravity

Specific gravity of acid is the measure of its concentration

Indicates the state of charge of flooded cell but not the capacity

Cell open circuit voltage = specific gravity + 0.845

The specific gravity of battery is decided on

Battery technology

Battery application - operating temperatureBattery life.

Sp. Gravity varies with temperature


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Higher gravity Lower gravity

More capacity Less capacityShorter life Longer life

Less space More space

Better cranking Poor cranking

How Specific gravity of Acid Influence on Battery?


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Typical specific gravities for certain applications are

1.30 VRLA (in general)

1.28 Heavily cycled batteries -traction

1.26 Automotive (SLI)

1.25 UPS/Solar photovoltaic (SPV)

1.22 Train lightings

1.20 General applications such as power utility


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The benefits

No water top up Long life on float service

Excellent shelf life

No corrosive fumes Ready to use

Stackable with horizontal orientation

Low weight and volume

Safe to use

Faster installation

Since 1977


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Performance Characteristics

Ampere hour efficiency : >95 %

Watt hour efficiency : >85%

Self discharge : less than 3% per month Oxygen recombination : >98%

efficiency

Since 1977

Eff f Di h R d T B


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Effects of Discharge Rate and Temperature on Battery

Less the rate of discharge more the capacityBattery of 100Ah @ 10Hr rate give around 50Ah @ 1 Hr. rate

Less the operating temperature less the capacity more the life

More the depth of discharge less the life

BATTERY APPLICATIONS


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Starting, Lighting, and Ignition (SLI)

Momentary high rate

Partial float

Low capacity

Pasted plate design.

TractionMotive power for electric or hybrid vehicles

High capacity to weight and volume rat io

Deep cycling

Typical applications - Fork l if ts, Electric cartsTubular plate design

BATTERY APPLICATIONS


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Stationary

Standby battery (UPS and Telecom Equipment)

Work Generally in Float Mode

Medium to low rate discharge

Long backup

Solar Photovoltaic (SPV)

Generally stand-alone

Re-charged by the solar energy

Deep cyclic & PSOC operation


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DISCHARGE CHARACTERISTIC CURVES AT 27oC

Voltage

Discharge Time

C IS THE RATED CAPACITY OF THE BATTERY. THE AVAILABLE

CAPACITY DEPENDS ON STATE OF CHARGE AND ON TEMPERATURE

1 2 4 6 8 10 20 40 60 2 4 6 8 10

2.10

2.00

1.90

1.80

1.70

1.60

1.503 CA 2 CA

1 CA0.7 CA

0.28 CA0.1 CA

Since 1977

C i i i i


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Capacity Variation w ith Temperature

0

10

20

30

40

50

60

70

80

90

100

110

120

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60

Temperature in C

RatedCapacityin

%

Capacity Variation with TemperatureSince 1977


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A. Constant Voltage ChargingCharging the battery at Constant Voltage

Current wil l come down as the Battery gets Charged

No chance of High Current charging

Dual Mode with FC-BC facili ty

B. Constant Current ChargingCharging battery at same current

Better charging fast charging

High gassing more water loss

Appropriate for cyclic operation

Not suitable for VRLA (in general)

Split-rate charger more safe as it pumps high initial current to the cell

and then switches to a low rate based on time of charge, voltage or both.

Battery charging Methods


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c. Boost chargingFast charging at higher voltage when battery discharges to

higher depth Generally Float cum Boost chargers are usedin VRLA battery charging in site

D. Trickle ChargingContinuous constant-current charge at off lineE. Equalizing ChargeEqualize the cell voltage in Battery bank to avoid

over/under charge of cells

Documents

Basics & Working Principles of Batteries