How It's Made (2001–…): Season 1, Episode 13 - Bicycle Helmets/Lithium Batteries/Car Brakes/Aluminium - full transcript

Narrator:
TODAY ON "HOW IT'S MADE"...

BICYCLE HELMETS -- LETTING
SAFETY GO TO YOUR HEAD...

ALUMINUM -- PROBABLY THE MOST
VERSATILE METAL AROUND...

CAR BRAKES --
WE BRING YOU BREAKING NEWS

ABOUT HOW
THEY'RE MANUFACTURED...

AND LITHIUM BATTERIES --

YOU'LL GET A CHARGE
OUT OF THIS ONE.

IF YOU'RE SERIOUS
ABOUT BIKE-RIDING,

YOU SHOULD ALSO BE SERIOUS
ABOUT SAFETY,

AND IT ALL STARTS
WITH YOUR HEAD.

TODAY'S BIKE HELMETS MEET ALL
THE REQUIRED SAFETY STANDARDS



AND COME IN A WIDE RANGE
OF COLORS AND STYLES,

WHICH MEANS
YOU CAN PROTECT YOUR HEAD

AND LOOK GREAT DOING IT.

A BICYCLE HELMET IS CONSTRUCTED
OF AN EXTERIOR SHELL

AND AN INTERIOR ONE
OF POLYSTYRENE FOAM

DESIGNED TO ABSORB SHOCKS.

SOME DESIGNS FOR BICYCLE HELMETS
ARE DRAWN BY HAND

AND WITH
COMPUTER-AIDED GRAPHICS.

THE DESIGN
HAS TO TAKE INTO ACCOUNT

THAT IT IS NOT ON
A FLAT SURFACE,

BUT ON A ROUNDED ONE.

THIS CREATES OPTICAL DEFORMITIES
THAT HAVE TO BE CORRECTED.

FABRICATION BEGINS
WITH THE EXTERIOR SHELL.

THIS POLYMER SHEET
IS HEATED IN A HEAT FORMER



AT A TEMPERATURE
OF 65 DEGREES CENTIGRADE.

THE MOLD LIFTS THE SHEET

AND SUCTIONS IT TO FILL
ALL THE CAVITIES OF THE MOLD.

THIS OPERATION LASTS ABOUT
ONE MINUTE

AND PRODUCES FOUR SHELLS.

THEN, WHEN COOLED DOWN
AND HARDENED,

THE FOUR SHELLS
ARE CUT BY HAND.

VENTILATION OPENINGS ARE CUT
WITH A HEATED WIRE APPARATUS.

THESE OPENINGS
HAVE BEEN PREFORMED

DURING MOLDING OF THE SHELL.

THE HEATED WIRE EASILY
AND NEATLY CUTS THE POLYMER.

NEXT UP, TRIMMING THE HELMET
TO ELIMINATE EXCESS POLYMER.

THE CIRCUMFERENCE
IS MANUALLY CUT USING A ROUTER.

THE EDGES ARE THEN SANDED
TO EVEN THEM.

IT IS ALSO POSSIBLE TO CUT
THE CIRCUMFERENCE OF THE SHELL

WITH A HEATED WIRE.

THIS OPERATION
TAKES MORE TIME,

BUT IS MORE PRECISE BECAUSE
OF THE RESULTING CLEANER CUT.

NOW THEY'RE GOING TO FABRICATE
THE FOAM INTERIOR

THAT WILL BE PLACED
INSIDE THE SHELL.

IT'S MADE
OF POLYSTYRENE BEADS

THAT WILL EXPAND
AND BOND TOGETHER.

THIS EXPANDER INCREASES
THE VOLUME OF THE GRANULES

THAT FALL INTO IT.

STEAM AND AN AGITATOR

LET THE POLYSTYRENE BEADS
EXPAND UNIFORMLY.

THE GRANULES ARE NOW READY.

THE CONTENTS OF THIS BIN

WILL BE ABLE TO PRODUCE
ABOUT 20 FOAM PIECES,

WHICH WILL TAKE SHAPE
ON THESE MOLDS.

THE PRESS CLOSES UP FOR
THE SIX MINUTES THAT IT TAKES

TO MOLD FOUR FOAM PIECES.

THE PARTICLES FUSE WITH STEAM
BEFORE BEING COOLED WITH WATER.

THE FOAM IS REMOVED
FROM THE MOLD.

FORMS ARE PRODUCED
FOR DIFFERENT HELMETS.

FUSING OF THE PARTICLES

HAS WELDED THE GRANULES
TO ONE ANOTHER.

DEPENDING ON THE HELMET MODEL,

OPENINGS HAVE TO BE MADE
WITH THIS HEAT IRON

TO ALLOW FOR INSTALLATION
OF AN AIR-VENT ACCESSORY.

ALL THAT REMAINS IS TO MAKE
THE ADJUSTMENT PADS,

CUT WITH
THIS PRESS-POWERED STAMPER.

THE ADJUSTMENT PADS
ARE HELD IN WITH VELCRO

TO ALLOW EASY ADJUSTMENT
OF THE HELMET.

THIS ALLOWS THE CYCLIST
TO CHANGE THE FOAM PADS

FOR GREATER COMFORT.

INSERTING THE STRAPS CALLS
FOR GOOD MANUAL DEXTERITY

AND TAKES ONLY A MINUTE.

THE SHELL AND THE POLYSTYRENE
FOAM LINER HAVE TO BE JOINED.

THEY'RE ADJUSTED
ONE INSIDE THE OTHER,

THEN SOLIDLY SECURED
WITH ADHESIVE TAPE.

THE HELMET IS NOW COMPLETED.

AND NOW IT'S READY
FOR PACKAGING.

THE SAFETY HELMETS
HAVE TO BE CERTIFIED,

GUARANTEEING THEIR SAFETY,
AND CONFORMITY TESTS ARE DONE.

AT LEAST ONE HELMET IN 500 WILL
UNDERGO THIS DESTRUCTIVE TEST.

HERE, IT DROPS VERTICALLY
ONTO A PIECE OF STEEL.

THIS FACILITY CAN PRODUCE
UP TO 4,000 HELMETS DAILY

IN HUNDREDS OF MODELS
AND OVER 500 VARIATIONS.

Narrator: TAKE A LOOK AROUND,

AND YOU'LL FIND
THIS WONDER METAL EVERYWHERE,

IN EVERYTHING FROM SCREEN DOORS
TO JET PLANES.

ALUMINUM
HAS SO MANY APPLICATIONS

BECAUSE IT'S LIGHT AND STRONG,

AND IT'S CORROSION-
AND CRACK-RESISTANT.

PRODUCING ALUMINUM IS COSTLY,
BUT IT SAVES MONEY OVER TIME.

ALUMINUM --
SO WIDELY USED TODAY,

AND THE WORLD'S
MOST ABUNDANT METALLIC ELEMENT,

DOES NOT OCCUR
IN A NATURAL STATE.

THE MOST AVAILABLE SOURCE
OF ALUMINUM IS ACTUALLY BAUXITE.

BAUXITE IS MAINLY MINED
IN TROPICAL COUNTRIES.

THE ALUMINUM ATOM IN BAUXITE
IS BONDED TO OXYGEN MOLECULES.

THESE BONDS HAVE TO BE BROKEN
BY ELECTROLYSIS

TO PRODUCE PURE ALUMINUM.

BAUXITE IS CARRIED BY RAIL
TO THE PLANT,

WHERE IT WILL BE CRUSHED.

THEN, THROUGH
A CHEMICAL TRANSFORMATION

CALLED THE BAYER PROCESS,
ALUMINA IS EXTRACTED.

THIS IS THEN ROASTED
IN CALCINERS

TO ELIMINATE ALL MOISTURE.

THIS IS
THE REDUCTION FACILITY.

THIS PLANT HAS 432 POTS

THROUGH WHICH A POWERFUL
ELECTRIC CURRENT WILL BE PASSED

TO PRODUCE ELECTROLYSIS.

AN OVERHEAD CRANE
DUMPS ALUMINA INTO THE POTS.

THEN THE ELECTRIC CURRENT
FROM THE ANODE

PASSES THROUGH THE ALUMINA

THAT WE SEE HERE
AT THE BOTTOM OF THE POT.

VIA THE PROCESS OF ALUMINA
REDUCTION AT 1,742 DEGREES,

THE ANODES LOSE VOLUME
AND WILL HAVE TO BE REPLACED.

IT'S A CONTINUOUS OPERATION.

EACH ANODE HAS A LIFE-SPAN
OF ABOUT 20 DAYS.

SPENT ANODES ARE RECOVERED FROM
THE POT WITH THIS OVERHEAD CRANE

AND CARRIED OFF TO BE RECYCLED.

THEY CLEAN THE ALUMINUM RODS,
WHICH WILL THEN BE REUSED.

HERE WE SEE THE CRUST FORMED
ATOP THE ANODE.

WHEN THE ANODES ARE REPLACED,

THE ACCUMULATED IMPURITIES
HAVE TO BE RECOVERED

FROM THE TOP OF THE POTS.

THIS IS ACCOMPLISHED
WITH THESE PINCERS.

THEN A NEW ANODE IS INSERTED
INTO THE ALUMINA,

AND ELECTROLYSIS CONTINUES.

THE ELECTRIC CURRENT
BREAKS THE MOLECULAR BONDS.

THE HEAVIER ALUMINUM COLLECTS
AT THE BOTTOM OF THE POT,

WHILE THE OXYGEN BOUND TO
FLUORINE IS RELEASED AS A GAS,

WHICH IS DRAWN OFF
AND TREATED.

THE LIQUEFIED ALUMINUM REMAINS
AT THE BOTTOM OF THE POT.

IT HAS TO BE RECOVERED IN THIS
HUGE CRUCIBLE WITH A TUBE.

THE TUBE IS DIPPED
INTO THE BOTTOM OF THE POT,

AND A VACUUM SYSTEM
DRAWS THE MOLTEN ALUMINUM

FROM THE CRUCIBLE.

THE ALUMINUM IS RECOVERED
IN A SHORT TIME.

AIR IS VACUUMED
FROM THE CRUCIBLE

BY A FLEXIBLE PIPE
HELD BY AN OPERATOR.

THE TUBE
IS FINALLY WITHDRAWN,

AND THE OVERHEAD CRANE DUMPS
ANOTHER QUANTITY OF ALUMINA

INTO THE POT.

THUS, THE ALUMINUM-FABRICATION
PROCESS CONTINUES UNINTERRUPTED.

THE CRUCIBLES FILLED
WITH MOLTEN ALUMINUM

ARE TRANSPORTED
TO THE CASTING HOUSE.

THEIR CONTENTS ARE POURED
INTO HOLDING FURNACES,

THAT HAVE A CAPACITY
OF 60 TONS.

IN THESE VERY HOT FURNACES,

THE MOLTEN ALUMINUM
IS STORED TO AWAIT CASTING.

FINALLY, CASTING BEGINS.

THE ALUMINUM CAN BE
SEMICONTINUOUSLY

VERTICALLY CAST, PRODUCING
INGOTS, SHEETS, OR BILLETS,

OR IT CAN BE DIRECTLY CAST
INTO SEMIFINISHED PRODUCTS.

THE COOLING OF ALUMINUM PIECES
IS ACCELERATED BY WATER SPRAYS.

THE LARGE, RECTANGULAR INGOTS,
WHICH CAN WEIGH UP TO 25 TONS,

WILL HEAD FOR HOT-ROLLING,

AND EVENTUALLY
WILL BE FABRICATED INTO PRODUCTS

LIKE ALUMINUM FOIL.

FROM FOUR TO FIVE TONS
OF BAUXITE

HAVE PRODUCED TWO TONS
OF ALUMINA,

WHICH IN TURN PRODUCES
ONE TON OF ALUMINUM.

THIS PARTICULAR PLANT PRODUCES

200,000 TONS
OF ALUMINUM ANNUALLY.

SOME OTHER FACILITIES
CAN TURN OUT AS MUCH

AS 400,000 TONS.

Narrator: IF YOU'VE EVER
HAD TO STOP SUDDENLY

WHILE DRIVING AT HIGH SPEED,

YOU KNOW THAT
ONCE YOU HIT THE BRAKES,

THEY CAN EASILY LOCK UP,
MAKING YOU SKID.

BUT WITH THE SOPHISTICATED
COMPUTER TECHNOLOGY

BEHIND TODAY'S ANTILOCK BRAKES,

SKIDDING IS BECOMING
A THING OF THE PAST.

BRAKES ARE ABSOLUTELY
ESSENTIAL EQUIPMENT

FOR EVERY VEHICLE
TO SLOW DOWN AND STOP.

AND BRAKES HAVE REMAINED
PRACTICALLY UNCHANGED

FOR THE PAST 40 YEARS.

CONVENTIONAL DISK BRAKES
HAVE PADS

THAT PRESS AGAINST THE BRAKE
DISK ATTACHED TO THE WHEEL.

THESE PADS GRIP THE DISK

ON ONLY 15 TO 30 DEGREES
OF ITS CIRCUMFERENCE.

THIS DEVELOPS HIGH HEAT,
WHEEL SKIDDING,

AND RESULTS IN PREMATURE WEAR.

THE NEW FLOATING DISK BRAKES

HAVE TWO PADS
OF FRICTION MATERIAL

ON 360 DEGREES OF THE DISK.

WHEN THE BRAKE IS APPLIED,

HYDRAULIC PRESSURE
ACTIVATES THE DIAPHRAGM,

WHICH APPLIES PRESSURE
ON THE INBOARD PAD,

WHICH IS THEN PRESSED
AGAINST THE DISK.

IN THIS ANIMATION, THE DIAPHRAGM
MOVEMENT IS EXAGGERATED.

HOWEVER SIMPLE,
THE DESIGN OF THIS BRAKE

CALLS FOR SOME
COMPLEX DEVELOPMENT STEPS.

IT ALL STARTS
ON THE MONITOR SCREEN

WITH COMPUTER-AIDED DESIGN.

THIS POWERFUL SOFTWARE CREATES
OBJECTS IN THREE DIMENSIONS,

WHICH CAN BE
VIRTUALLY MANIPULATED.

THEY THEN PROCEED
TO DIGITAL ANALYSIS.

HERE, DIGITAL MODELS ARE
SUBMITTED TO REPEATED BRAKING

TO VERIFY THAT THE PARTS
CONFORM TO DESIGN OBJECTIVES.

THE SOFTWARE VERIFIES CHANGES
IN HEAT,

THE EFFECTS OF VIBRATION,
AND RESISTANCE TO BREAKAGE.

THE RIGHT CHOICE OF MATERIALS
IS CRITICAL.

THE ELECTRICAL COMPONENTS
ALSO HAVE TO BE CREATED.

HERE, WE SEE THE DELICATE
CONSTRUCTION OF TINY SENSORS,

THAT MEASURE THE FORCE EXERTED
BY THE BRAKING SYSTEM.

THE SENSOR IS THE MAIN COMPONENT

OF THE INTELLIGENT
A.B.S. BRAKING SYSTEM,

WHICH FUNCTIONS
MORE EFFICIENTLY

THAN TRADITIONAL
ANTISKID SYSTEMS

AND REDUCES BRAKING DISTANCE.

NEXT, IT'S THE FABRICATION STAGE
OF PROTOTYPE PARTS,

WHICH WILL BE TESTED.

THE MACHINING OF THESE PARTS
MUST TAKE INTO ACCOUNT

THE REQUIREMENTS
OF MASS PRODUCTION.

THIS HIGH-PRECISION,
ROBOTIZED MACHINING

IS DONE BY COMPUTER-CONTROLLED
DIGITAL MACHINES.

A LIQUID SPRINKLED
ON THE MACHINE PART

COOLS IT DURING THE PROCESS.

THE FINISHED PARTS
ARE PRECISELY MEASURED,

THEN FITTED AND ASSEMBLED TO
FORM THE TOTAL BRAKING SYSTEM,

WHICH WILL BE FIRST TESTED
IN THE LABORATORY.

BRAKES IN FULL CONTACT
HAVE A FRICTION SURFACE

SIX TIMES SUPERIOR
TO TRADITIONAL BRAKES.

THE USE OF ALUMINUM
AND COMPOSITE MATERIALS

ALLOW FOR A WEIGHT SAVINGS
OF 5.5 POUNDS PER WHEEL.

THIS AFFECTS ROADHOLDING
AND REDUCES FUEL CONSUMPTION

BY .05 GALLONS
PER 100 MILES.

THEY PROCEED TO POWER
AND ENDURANCE TESTS

ON THIS DYNAMOMETER, IN WHICH
A BRAKE AND WHEEL ASSEMBLY

ACT AGAINST
A LARGE ROTATING DRUM.

THESE LAB TESTS ARE CRITICAL,

SINCE THEY CAN DETECT ANY DEFECT
IN A BRAKING SYSTEM

BEFORE IT'S INSTALLED
ON AN ACTUAL VEHICLE.

IN ORDER TO EVALUATE THE POWER
AND ENDURANCE OF THE BRAKES

IN FULL APPLICATION
UNDER EXTREME CONDITIONS,

THEY WERE INSTALLED
ON THIS PORSCHE 911 TURBO

ENTERED IN THE MOTOROLA CUP.

THEY PROVED
COMPLETELY SATISFACTORY,

AND THE PORSCHE WENT ON
TO RECORD MANY WINS.

ONCE ALL VALIDATION TESTS
ARE DONE,

WE MOVE ON
TO THE NEXT STEP.

BRAKES ARE INSTALLED ON
A PRODUCTION-MODEL VEHICLE.

WITH DATA SYSTEMS,

ENGINEERS CAN OBSERVE
THE PERFORMANCE OF BRAKES

UNDER ALL CONDITIONS
THOUSANDS OF TIMES A SECOND.

FINALLY, ENGINEERS PROCEED
WITH ACTUAL BRAKING TRIALS

WITH TEST VEHICLES.

ALL THAT REMAINS IS TO PRODUCE
BRAKES ON A LARGE SCALE

TO SUPPLY AUTO MANUFACTURERS'
PRODUCTION LINES.

AND THAT'S
THE STORY OF BRAKES,

FROM ORIGINAL IDEA
TO FINAL PRODUCT.

Narrator:
THERE'S NOTHING LIKE THE SOUND
OF A CAR ENGINE STARTING,

ESPECIALLY WHEN IT'S 15 BELOW
ON A WINTER MORNING.

TODAY'S AUTOMOTIVE BATTERIES
ARE SMALLER, MORE POWERFUL,

AND MORE EFFICIENT,
EVEN AT EXTREME TEMPERATURES.

IT'S ALL THANKS TO THE POWER
OF LITHIUM-ION-CELL TECHNOLOGY.

WHILE DISSECTING A FROG
IN 1786,

THE ITALIAN RESEARCHER GALVANI

NOTED THAT WHEN HIS SCALPEL
TOUCHED A LEG MUSCLE,

IT CONTRACTED FROM
AN ELECTRIC CURRENT PRODUCED.

LATER, VOLTA BELIEVED
THE CURRENT WAS PRODUCED

BY THE METAL INSTRUMENTS,

THE ANIMAL BEING
ONLY A CONDUCTOR.

TO PROVE IT, HE STACKED DISKS
OF ZINC AND COPPER

CONNECTED BY CONDUCTORS

AND FABRIC IMPREGNATED
WITH AN ACID SOLUTION.

AND SO, IN 1800,
THE ELECTRIC BATTERY WAS BORN.

BATTERIES POWER ALL KINDS
OF ELECTRIC MOTORS.

A NEW LITHIUM-METAL-POLYMER
BATTERY PACK SUCH AS THIS ONE

COULD SOON POWER
AN ELECTRIC AUTOMOBILE,

AS WELL
AS A HYBRID VEHICLE.

THIS BATTERY WILL BE MADE UP
OF FOUR COMPONENTS.

IT ALL STARTS
WITH THIS LITHIUM INGOT,

WHICH WEIGHS ABOUT 11 POUNDS.

IT'S TRANSFORMED INTO
A THIN SHEET

BY THIS EXTRUSION PRESS THAT
APPLIES 440 TONS OF PRESSURE.

THE PRESS CREATES A SHEET

THAT'S ONLY ABOUT
1/100 OF AN INCH THICK.

THE WHOLE EXTRUSION SEQUENCE
IS CLOSELY COMPUTER-CONTROLLED.

EXTRUSION IS NOW COMPLETED.

THE METALLIC LITHIUM SHEET

IS THE REQUIRED 1/100 INCH
IN THICKNESS,

OR 1/4 OF A MILLIMETER.

THE SHEET HAS TO BE
FURTHER THINNED.

PLACED ON A ROLLER,
IT IS CARRIED TO THE LAMINATOR.

AT ROOM TEMPERATURE,
IT'S THINNED ONCE AGAIN.

IN JUST 20 MINUTES,
THE 11-POUND INGOT

WILL HAVE BEEN TRANSFORMED INTO
A THIN SHEET .01 INCHES WIDE

AND SOME 655 FEET IN LENGTH.

THIS LAMINATOR COMPLETES
THE THINNING OF THE SHEET.

THE RESULTING
1 1/4 MILE-LONG SHEET

WILL ALLOW FOR THE FABRICATION
OF 210 BATTERY UNITS.

LITHIUM IS
A SOFT, STICKY METAL.

FOR THIS REASON,
A POLYPROPYLENE FILM

HAS TO BE FIXED
ONTO THE LITHIUM SHEET.

WITHOUT THIS PROTECTION,

THE SHEET WOULD ADHERE TO ITSELF
AND BECOME UNUSABLE.

THE SHEET WILL BE USED TO MAKE
INDIVIDUAL BATTERY CELLS.

THEN THESE CELLS
WILL BE ASSEMBLED,

IN SERIES AND IN PARALLEL,

AND INSERTED INTO MODULES
OF DIFFERENT SHAPES.

TO MAKE AN INDIVIDUAL
BATTERY CELL,

THE SHEET
HAS TO BE ROLLED UP.

THIS AUTOMATED SPOOLING MACHINE

WINDS UP THE LITHIUM FILM
IN 26 REVOLUTIONS.

THE WOUND-UP SHEET
IS PUT INTO A VACUUM OVEN,

WHERE THE VARIOUS LAYERS
ADHERE FIRMLY TO ONE ANOTHER.

THIS STEP LASTS
FOR ABOUT 90 MINUTES

AT 176 DEGREES.

HERE, A TEST IS MADE.

USING A VOLTMETER,
THE BATTERY IS CHECKED TO SEE

THAT IT PRODUCES
THE REQUIRED 3.56 VOLTS.

ANY PROBLEM CAN BE DETECTED HERE
AND CORRECTED.

A FINAL QUALITY CHECK
IS MADE WITH THIS CALIPER.

IT PRECISELY MEASURES THE
THICKNESS OF THE BATTERY CELL.

THE BATTERY CELLS
ARE THEN STORED.

METALLIC PLATES
ARE PLACED BETWEEN THEM

FOR THE ENTIRE STORAGE PERIOD.

ONE MORE STEP REMAINS,

AND THAT'S THE METALLIZING
OF THE CONTACTS.

THE BATTERY CELLS ARE SENT OFF
TO A FABRICATION FACILITY

IN THIS CONTAINER.

THE CONTAINER
IS ROBOTICALLY HANDLED.

FIRST, IT'S PUT INTO
A PROTECTIVE TANK.

THEN THE METALLIZING
OF THE CONTACTS IS DONE

BY SPRAYING ON MOLTEN METAL.

THIS TAKES
JUST A FEW SECONDS,

SINCE THE METAL COOLS
VERY QUICKLY.

THE BATTERY IS NOW FINISHED.

IT COMPRISES FOUR ELEMENTS --

LITHIUM,
WHICH ACTS AS THE ANODE,

A METALLIC OXIDE CATHODE,

A DRY
SOLID POLYMER ELECTROLYTE,

AND A METALLIC
CURRENT COLLECTOR.

ALL THAT REMAINS TO BE DONE

IS THE ASSEMBLING OF
THE INDIVIDUAL BATTERY CELLS

INTO A MODULE.

IT BEGINS WITH THE PLACING
OF INDIVIDUAL CELLS

ONTO ONE ANOTHER
AND ISOLATING THEM WITH FOAM

SO THAT THEY DO NOT TOUCH
EACH OTHER.

THESE RED SHEETS
ARE ACTUALLY HEATING ELEMENTS,

SINCE THE LITHIUM-METAL-POLYMER
CELLS FUNCTION

AT TEMPERATURES OF BETWEEN
104 AND 176 DEGREES.

HERE, WE SEE THESE MODULES
OF A BATTERY PACK

FOR A HYBRID VEHICLE,

AN AUTOMOBILE THAT WORKS
WITH A GASOLINE-POWERED MOTOR

AND AN ELECTRIC MOTOR.

THIS PROTOTYPE BATTERY

WAS CREATED FOR
A TOTALLY ELECTRIC VEHICLE.

IT SURPASSES HEAVY
TRADITIONAL LEAD-ACID BATTERIES

THAT CAN'T DEVELOP THE SAME
AMOUNT OF ELECTRICAL ENERGY

AND HAVE MUCH SHORTER
LIFE-SPANS.

CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS, INC.

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