B787 batteries

Copyright © 2013 Boeing. All rights reserved. 1

787 Program | Electrical System and Batteries Mike Sinnett Vice President & Chief Project Engineer 787 ProgramFebruary 2013

Copyright © 2013 Boeing. All rights reserved.

Airplane electrical systems

787 Dreamliner electrical system

Batteries

787 batteries

Questions and answers

Welcome


The system that makes, controls and distributes power to run airplane systems: Flight deck displays

Hydraulic system

Lighting

In-flight entertainment

Many others

Redundant systems and backups provide layers of safety.

For Your InformationOn the ground, the airplane also can run on electricity from ground carts.

What Is an Airplane Electrical System?


Electricity powers more on the 787 than on other Boeingairplanes:

Engine start

Environmental control system

Wing ice protection

High-capacity hydraulic pumps

Brakes

What Does More Electric Mean?

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More efficient energy creation, distribution, useBetter power controlAutomatic monitoring for

better airplane availability—Airplane Health ManagementMore fuel efficient Fewer maintenance tasks Lower maintenance costsBetter reliability Less drag Less noise

More Electric Brings More Benefits

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Electrical System ComparisonTraditional Airplane 787 Dreamliner


Two per engine (four total) Act as motors to turn the engine

shaft and start the engine Primary sources of electrical

power when engines are running Simplest, most efficient method

to generate powerConnect directly to the gearbox

Generate power in proportion to engine speed

235 volts alternating current (VAC)

250 kilovolt amps (kVA)

Generating PowerVariable-Frequency Starter Generators


Two per airplane Secondary sources of

electrical power when APU is running 235 VAC

225 kVA

Act as motors to start the auxiliary power unit, a small, turbine engine in the airplane’s tail

For Your InformationBoeing flew a 787 test flight for 5.5 hours with one engine and five of six generators turned off, demonstrating the robust capabilities of the system.

Generating PowerAPU Starter Generators


On the ground: Three external power

receptacles (115 VAC)

Auxiliary power unit

Main battery

APU battery

In flight:Backup power includes Main battery

APU battery

Ram air turbine

Other Power Sources


Most systems are fed byThe aft electrical equipment bay.

Power distribution units around the airplane.

Distribution unitsAre solid-state power controllers.

Weigh less than power feeders on other models.

Eliminate some wiring, thereby saving weight.

Distributing Power


Monitoring and Fault Protection Multifunction display System status available through

electrical and status pages

Notification, procedures for non-normal conditions, as with any other airplane

Generator control units Six total (one per VFSG; one per ASG)

Regulate voltage and provide fault current limiting

Bus power control unit Serve as communication gateway

between electrical and other systems

Control standby systems

Manage electrical, horsepower loads


Specific model needs

Lessons from in-service experience

Boeing design philosophy

No single failure can cause an accident

Redundant systems

Systems separation: physical and functional

Standby systems

Protective systems

U.S. Federal Aviation Regulations

Safety Is Designed InSystems Design Requirements

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Performance in Service

Months After Entry Into Service

Reliability(percentage)

Schedule Reliability from Entry into ServiceThrough December 2012


Provide power (discharge). Store energy.

For Your Information:Energy vs. Power Energy is an expression of

the quantity of work that can be performed. Power describes the rate

of use of energy. It is similar to the difference between

distance and speed.

What Do Batteries Do?

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A battery is essentially a container of chemicals that releases electrons.

Batteries have two terminals –positive and negative.

When the negative and positive terminals are connected, a chemical reaction occurs that results in the flow of electrons.

The flow of electrons is called current and is measured in amps.

As more current flows through the item being powered, the battery is delivering more power.

How Do Batteries Work?

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Where Are the 787 Batteries?

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Auxiliary Power Unit Battery Aft electronics equipment bay;

lower fuselage; near the back of the airplane.

Main Battery Forward electronics equipment

bay; lower fuselage near the front of the airplane.


What Do the 787 Batteries Do?

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Auxiliary Power Unit BatteryAPU start

APU provides ground power and serves as backup power in flight.

Main Battery Ground maintenance

operations: Refueling.

Brake power while towing.

Navigation lights while towing.

Backup power.


Parts of the 787 Battery

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Insulation

Cell (1 of 8)

Negative Terminal (copper)

Positive Terminal (aluminum)

Insulation

Current Sensor

Frame

Spacer

Contactor

Battery Monitoring

Unit

Connector

Top Frame

Wire Harness


Aerospace Applications of NiCd

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747

MD-11

777


High power capability. Lower weight. Improved charging

characteristics. No memory effect. Improved storage life.

For Your Information: Lithium is an alkali metal with characteristics

similar to sodium and potassium. It is the third element on the periodic table. Lithium is the lightest metallic element.

Why Select a Lithium-Ion Battery?

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Aerospace Applications of Li-Ion

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Mars Rover

702 Commercial Communication Satellite

Image Credit: NASA/JPL-Caltech


Comparison of the 787 and 777 Batteries

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Chemistry Feature Lithium-Ion(Lithium Cobalt Oxide)

Nickel Cadmium(Fibrous)

Hermetically sealed No Yes

Voltage (nominal) 32V (8 cells) 24.0 V (20 cells)

Maximum weight 63 lb (28.6 kg) 107 lb (48.5 kg)

Current provided for airplane power-up 150 amps 16 amps


Airplane-level Design to preclude failure and

assume failure will occur. Design protections.

Ensure that no single failure will cause danger to the airplane.

Battery system Provide circuit protection against

overcharging and deep discharging. Provide mechanical protection to

withstand failures and protect other systems and structure.

Design Philosophies

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Laboratory testing of battery system +5,000 hours – demonstrated normal operations and simulated

failures including baking the battery to induce overheating, crush testing and puncturing a cell with nail to induce short circuit

Laboratory testing of integrated power system +25,000 hours – demonstrated interaction of various system

elements in normal operations and simulated failures in two laboratories

Airplane testing of integrated electrical system +10,000 hours – normal operations and simulated failure

conditions including extreme weather conditions, long duration and short duration operations, low- and high-elevation operations

Rigorous and Robust Testing

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787 In-Service Battery History

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January 2013 APU battery fault – under investigation by the NTSB Main battery fault – under investigation by the JTSB

Prior to January 2013 2.2 million cell-hours in operations (includes Boeing and airline

ground and flight hours, eight cells per battery) 50,000 hours flying No battery incident events on an airplane Standard battery issues, comparable to other airplanes


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B787 batteries