Electrical and Magnetic Materials for Automotive Manufacturing

SAMAERC Automotive Engineering
Case study on:
Electrical and Magnetic Materials for
Automotive Manufacturing
By: Dawit Asres

KIOT MSC Automotive Engineering
Electrical and Magnetic materials for Automotive Manufacturing
Table of Contents
Abstract .......................................................................................................................................I
1. Introduction............................................................................................................................ 1
2. Automotive Electrical Parts and Materials ............................................................................. 1
2.1. BATTERY ..................................................................................................................... 1
2.2. ELECTRICAL COMPONENTS................................................................................... 3
2..3. IGNITION SYSTEMS.................................................................................................. 7
2.4. WIRING, LIGHTING AND OTHER INSTRUMENTS AND SENSORS................... 7
3. Magnetic components of an automotive ................................................................................. 8
3.1. Magnetic applications .................................................................................................... 8
3.2. Magnetic materials....................................................................................................... 10
4. The Future ............................................................................................................................ 11
5. Conclusions.......................................................................................................................... 11
6. References ............................................................................................................................ 12

I
Abstract
Automotive electrical system has gradually evolved over the years and today it assimilates
computer control of the automotive mechanics. This paper presents the electrical and magnetic
materials for automotive applications. The major electrical and magnetic components of an
automotive together with the materials that are used to make them are discussed. Special focus is
given to current electrical and magnetic materials used in making charging system components,
generators and alternators, ignition systems, wiring, lighting and other instruments and sensors.

1
1. Introduction
Need for higher fuel efficiency, weight minimization, environmental regulations and policies as
well as customer demand forces the auto maker companies to focus on electrification of car.
Electrification of the automobile was the challenge at the beginning of the 20th century. At the
turn of the century, there were more electric automobiles than gasoline powered automobiles in
the U.S. In 1912 Charles Kettering introduced the first electrical system on a car (about 200W)
making possible electric starting, lighting and ignition, forever changing the usefulness of the
automotives. As we enter the 21st
century, the same challenge resurfaces in light of the need to
reduce emissions and dependency on foreign oil.
Applications of magnetic and electrical materials grow exponentially every few years. This is
certainly true in the automotive sector. The modern automotive market demands an increasing
degree of sophistication in both the control and comfort of its products. Today’s gasoline or
petrol cars have electric motors for door mirror positioning, window lift, seat positioning, and
engine cooling fans. In addition Air Conditioning, ABS and anti-skid, multi speaker radio and
CD systems are today not just encountered in prestige products but are fitted as standard on most
models. The average modern car contains upwards of two hundred magnets covering all these
applications and large number of electrical components.
Electrical and magnetic materials are used in various automotive components such drive by wire,
Electrical steering, Braking systems, Climate control, and Headlight positioning, coupled with
the planned move to adopt higher voltages in automotive electrics. There is a dramatic growth
trend in automotive magnetic and electrical material usage while electrical components
encompass almost all parts that are magnetic and there are plenty of additional components.
The main factors for selecting the electrical and magnetic materials, especially for electrical and
magnetic parts, are numerous and include thermal, chemical or electrical resistance, easy
manufacturing and durability. Affordability is an important issue in vehicle electrical and
magnetic materials manufacturing, which includes factoring in the costs associated with a car’s
complete life–cycle, including manufacturing, operating and disposal costs.
The importance of materials selection in the product development process has been well
recognized since past decades. Various materials are used to make electrical and magnetic parts
of automotives.
2. Automotive Electrical Parts and Materials
2.1. BATTERY
Battery is device made of electrochemical cells that convert stored chemical energy to electrical
energy and electrical energy to chemical energy. Automotive battery is a rechargeable electronic
device that supplies electrical energy to automobiles. Traditionally, batteries are used for starting
engines, powering cranking motors, interior circuits, external appliances and telemetric in
automobiles. These batteries are majorly employed in passenger vehicles, electric vehicles,
commercial vehicles and among others.

2
There are different types of batteries as Lead Acid Battery, Nickel – Cadmium Battery, Nickel
Metal hydride, Hybrid Battery, Sodium Sulfur Battery and Aluminum Air Battery
The key constituents of LIBs are lithium (Li), cobalt (Co), nickel (Ni) and manganese (Mn)
which are used for the battery cathodes (Figure 1), and graphite used in the anodes. Various
classes of LIBs are currently used, the most important for EV being lithium nickel manganese
cobalt oxide (NMC) type. Within the NMC class there are many commercially available
compositions which vary considerably in the relative proportions of Ni, Mn and Co used.
Changes to the chemistry of the electrolyte and of the anode materials used in LIBs may also be
implemented within a few years.
Fig. 1 Major components of the starting system
Lead Acid Battery
 Lead acid batteries are made of dilute sulfuric acid, sponge lead, and lead oxide plates
situated within a plastic casing.
Nickel Cadmium
 Nickel Cadmium: is rechargeable type battery using nickel hydroxide and metallic
sponge cadmium as electrodes and potassium hydroxide within a plastic casing.
Nickel Metallic Hydride
 Nickel Metallic Hydride is a type of rechargeable battery similar to a nickel-cadmium
(NiCd) battery but using a hydrogen-absorbing alloy for the negative electrode instead of
cadmium.
Nickel (Fe): nickel-iron battery
 Nickel (Fe): nickel-iron battery is a storage battery having a nickel(III) oxide-hydroxide
cathode and an iron as anode with an electrolyte of potassium hydroxide. The active
materials are held in nickel-plated steel tubes or perforated pockets.

3
Sodium Sulfur
Sodium Sulfur: is type of battery constructed from molten sodium (Na) and sulfur (S) enclosed
in molybdenum and chromium.
Lithium Polymer
Evolved from lithium-ion batteries where the lithium-salt electrolyte is held in a solid
polymer composite such as polyethylene oxide or polyacrylonitrile.
Lithium Iron Disulfide
The lithium-iron disulfide cell is a sandwich of a lithium anode, a separator, and iron
disulfide cathode with an aluminum cathode collector.
Metal-Air and zinc-air fuel cells
Are electro-chemical batteries powered by the oxidation of zinc with oxygen from the air.
2.2. ELECTRICAL COMPONENTS
 Starter Motor
The starting motor converts electrical energy from the battery into mechanical or rotating energy
to crank the engine. The main difference between an electric starting motor and an electric
generator is that in a generator, rotation of the armature in a magnetic field produces voltage. In a
motor, current is sent through the armature and the field; the attraction and repulsion between the
magnetic poles of the field and armature coil alternately push and pull the armature around. This
rotation (mechanical energy), when properly connected to the flywheel of an engine, causes the
engine crankshaft to turn. Parts can be seen below in generators.
Fig.2 Starter motor
Materials that are commonly used in manufacture of stator motor are steel, iron core, copper, die-
cast aluminum and magnesium, silicon steel, lead, cast iron , plastics and zinc.

4
Starter Switches and Solenoids
A solenoid is simply a specially designed electromagnet. A solenoid usually consists of a
cylindrical coil wound with one or more layers of insulated wire and a movable iron core called
the armature. When current flows through a wire, a magnetic field is set up around the wire. If
we make a coil of many turns of wire, this magnetic field becomes many times stronger, flowing
around the coil and through its center in a doughnut shape. The length of the solenoid is much
larger in comparison with its diameter. When the coil of the solenoid is energized with current,
the core moves to increase the flux linkage by closing the air gap between the cores. The
movable core is usually spring-loaded to allow the core to retract when the current is switched
off. The force generated is approximately proportional to the square of the current and inversely
proportional to the square of the length of the air gap.
Materials commonly used in making solenoid and starter switches are: Insulating housing, poly
carbonate, glass, Aluminum, pvc, Brass, copper, Synthetic resin, zinc, stainless steel and
fluorocarbon as seal are the most common material that are used in manufacture of Starter
Switches and Solenoids.
2.2.2.Charging system components
For many applications, the charging circuit is one of the simplest on the vehicle. The main output
is connected to the battery via a suitably sized cable (or in some cases two cables to increase
reliability and flexibility), and the warning light is connected to an ignition supply on one side
and to the alternator terminal at the other.
It consists of many parts including alternator, regulator (which is usually mounted inside the
alternator) and the interconnecting wiring.
Fig. 3 Components of the charging system

5
 Alternator
The alternator generates electrical power to run accessories and to recharge the batteries. It is
normally driven by a belt located off the crankshaft. Mechanical energy from the crankshaft is
converted by the alternator into electrical energy for the batteries and accessories.
The alternator contains three main components:
 Stator (attached to alternator housing, remains stationary),
 Rotor (spins inside the stator),
 Rectifier,
Slip ring and brushes make an electrical connection to the spinning rotor.
b) Voltage regulator
The voltage regulator acts as an electrical traffic cop to control alternator output. It senses when
the batteries need recharging, or when the vehicles electrical needs increase, and adjusts the
alternators output accordingly. i.e., it controls the alternator’s output current to prevent over
charging and under charging of the battery. It does this by regulating the current flowing from
the battery to the rotor’s field coil.
Materials commonly used in making charging system components are: tin, lead, zinc,
copper, steel, copper, aluminum, magnesium, cast iron and different alloys.
2.2.3.Generators and Alternators
DC Generator: consists of four parts mainly,
a) Field System
The object of the field system is to create a uniform magnetic field within with the armature
rotates. Electromagnets are preferred on the account of their magnetic effects and field strength
regulation which can be achieved by controlling the magnetizing current.
b) Armature
It is a rotating part of a DC machine and is built up in a cylindrical or drum shape. The purpose
of armature is to rotate the conductors in the uniform magnetic field. It consists of coils of
insulated wires wound around an iron and so arranged that electric currents are induced in these
wires when the armature is rotated in a magnetic field.
c) Commutator
It is a form of rotating switch. They are placed between armature and external circuit. The
commutator will reverse the connections to the external circuit at the instant aech reversal of
circuit in the armature coil.
d) Brushes & Bearings
Brushes are made of carbon or graphite. It collects current from the commutator and conveys it
to external load resistance. It is rectangular in shape. Brushes are housed in brush holders and
mounted over brush holder studs. Ball bearings are used as they are reliable for light machines.
For heavy machines roller bearings are used.

6
Working principle
According to Faraday's law of electromagnetic induction, when a conductor moves in a magnetic
field (thereby cutting the magnetic flux lines), a dynamically induced emf is produced in the
conductor. The magnitude of generated emf can be given by emf equation of DC generator. If a
closed path is provided to the moving conductor then generated emf causes a current to flow in
the circuit.
Thus in DC generators, as we have studied earlier, when armature is rotated with the help of a
prime mover and field windings are excited (there may be permanent field magnets also), emf is
induced in armature conductors. This induced emf is taken out via commutator-brush
arrangement.
The main components of Generators and Alternators are made up of copper, aluminum,
magnesium, lead, steel, stainless steel, cast iron, iron core and zinc.
e) Voltage and Current Regulation
Silicon, germanium, cuprous oxide, selenium, ziner are the common materials used for making
regulators.
f) Relays
Relays are used throughout the automobile. Relays which come in assorted sizes, rating, and
applications, are used as remote control switches which can be controlled by another switch such
as horn switch or computer as in power train control module. A typical vehicle can have 20
relays or more.
Fig. 4 Relay
Materials commonly used in making relays are: Cupper, Soft iron, silver cadmium oxide, tin
oxide, silver nickel, silver cadmium oxide and silver tin oxide.
g) Charging circuits for D.C. Generator
Materials commonly used in making Charging circuits for D.C. Generator are: steel,
copper, aluminum and magnesium, cast iron.
h) A.C. Single Phase and Three Phase Alternators
Materials commonly used in making A.C. Single Phase and Three Phase Alternators are Iron
core, copper, aluminum, magnesium, lead, cast iron, stainless steel and zinc are the materials
that are most commonly used in alternators

7
2.3. IGNITION SYSTEMS
2.3.1. Battery Coil
The ignition coil is step up transformer to increase the voltage form 12 volt or 6 volt to 20000-
30000 volts. It consists of a primary winding and a secondary winding wound on a laminated
soft iron core. Primary winding contains about 300 turns made of thick wire. Secondary consists
of about 20000 turns of thin wire.
Materials commonly used in making Battery coil are copper and iron core
2.3.2. Circuits
Material that is commonly used in making circuits is copper.
2.3.3. Spark Plug
The function of the spark plug is to produce spark between its electrodes. This spark is used to
ignite the fuel-air mixture in the spark ignition (SI) engines.
The material chosen for the spark plug electrode must exhibit the following properties:
 High thermal conductivity.
 High corrosion resistance.
 High resistance to burn-off.
For normal applications, alloys of nickel are used for the electrode material. Chromium,
manganese, silicon and magnesium are examples of the alloying constituents. These alloys
exhibit excellent properties with respect to corrosion and burn-off resistance and other materials
such as Iridium, platinum, copper, Nickel and Ceramics are used in manufacturing of spark plug.
2.4. WIRING, LIGHTING AND OTHER INSTRUMENTS AND
SENSORS
2.4.1 Automotive Wiring
Electrical power and control signals must be delivered to electrical devices reliably and safely so
that the electrical system functions are not impaired or converted to hazards. To fulfill power
distribution one and two wire circuits, wiring harnesses, and terminal connections are used.
Materials that are commonly used in making automotive wiring are Copper, aluminum, tin, silver
and nickel.
2.4.2. Head Lamp and Indicator Lamp
The lighting system consists of all of the lights used on the vehicle. This includes Headlights, front and
rear park lights, front and rear turn signals, side marker lights, daytime running lights, cornering lights,
brake lights, back-up lights, instrument cluster backlighting, and interior lighting.
Materials commonly used in making Head Lamp and Indicator Lamp are : glass ,soda lime
silicate ,Borosilicate glass, alumina silicate glass ,Quartz, sodium resistance glass, ceramics,
porcelain, statite, tungsten, molybdenum, nickel, aluminum, steel, stainless steel, copper, non
ferrous alloys and solder getter are materials most commonly used in lamps.

8
2.4.3. Electrical and Electronic Fuel Lift Pumps
The pump creates positive pressure in the fuel lines, pushing the gasoline to the engine. The
higher gasoline pressure raises the boiling point.
Cars with electronic fuel injection have an electronic control unit (ECU) and this may be
programmed with safety logic that will shut the electric fuel pump off, even if the engine is
running. In the event of a collision this will prevent fuel leaking from any ruptured fuel line.
Additionally, cars may have inertia switch (usually located underneath the front passenger seat)
that is "tripped" in the event of an impact, or a roll-over valve that will shut off the fuel pump in
case the car rolls over.
Materials commonly used in electrical and electronic fuel lift pumps are: Copper, stainless steel,
brass, cast iron, bronze, plastics, carbon steel, nickel copper alloy
2.4.4. Dash Board Instruments and their Sensors
a) Dashboard is an electronic device that stores and processes data and is capable of
operating other devices.
b) Horn is a device that produces an audible warning signal. Automotive electrical horns
operate on an electromagnetic principle that vibrates a diaphragm to produce a warning
signal.
c) Windshield wipers are mechanical arms that sweep back and forth across the
windshield to remove water, snow, or dirt. The operation of the wiper arms is through the
use of a wiper motor.
d) Power mirrors are outside mirrors that are electrically positioned from the inside of the
driver compartment. The electrically controlled mirror allows the driver to position the
outside mirrors by use of a switch. The mirror assembly will use built-in, dual drive,
reversible permanent magnet (PM) motors.
Materials commonly used in making Dash Board Instruments are: semiconductor materials,
ceramics, metallic materials, organic materials, piezoelectric materials, two dimensional
materials, nano materials, biomaterials, soft materials, metal organic materials, frameworks, soft
materials, meta materials, and chromogenic materials.
3. Magnetic components of an automotive
3.1. Magnetic applications
Magnetic applications fall into five broad categories: - Motor Applications, Sensing Applications,
Actuators, Instrumentation and Loudspeakers.

9
3.1.1.Motor Applications
Typical common applications include
 Power steering motors
 Starter motors
 Alternators
 Engine Cooling fans
 Windscreen Wipers
 Washer pumps
 Fuel pumps
 Antenna lift
 Window actuation
 Heat and Air conditioning motors
 Seating position motors
 Sunroof motors
 ABS pumps
 Engine water pumps
 Headlight positioning – Must be used to control the beam height of Gas Discharge
Headlamps but could be linked to steering to point in the chosen direction.
3.1.2.Sensing Applications
Typical common applications include :
 ABS and anti skid systems
 Headlight position
 Steering
 Road Speed
 Inertia sensing (Crash/Airbag)
 Throttle
 Engine speed (Crankshaft)
 Remote locking/unlocking
 Tyre pressure sensing
 Alarm and security
3.1.3.Actuators
Typical common applications include:
 Anti skid
 Suspension (both active and self leveling)
 Throttle
 Airbag
3.1.4.Instrumentation
 Dashboard instruments - including speed, engine speed, temperature, oil pressure etc.

10
3.1.5.Loudspeakers
 Sound systems
 Navigation and information systems
 Anti noise system – currently being used in commercial aviation but could make the
transition to Automotive usage in the near future
 Car Alarm Sounders.
3.2. Magnetic materials
The two magnetic materials historically used in automotive applications are Alnico & Sintered
Ferrite. Alnico (alloys of Al-aluminum, Ni-nickel and Co-cobalt) was traditionally used in sensing
and instrument applications, but escalating costs of Cobalt mean that other materials are more
commonly used today.
Sintered Ferrite arcs are used in DC motors and are therefore probably the commonest material
currently in use in automotive applications. Specific motor grades are available which are able to
offer high resistance to highly demagnetizing forces at start up, thus retaining maximum magnetic
strength.
Higher strength materials such as Samarium Cobalt alloys have been available for many years, but
their high price has precluded their use in all but the most extreme applications. The major
development in the past few years has been the availability of cheaper Neodymium Iron Boron
magnetic material (NdFeB) both in sintered and bonded types.
Although in the last few years of a patent licence, NdFeB can offer competitive pricing. NdFeB can
offer up to ten times the magnetic performance of Sintered Ferrite, therefore allowing
miniaturization of components with higher efficiencies. The two drawbacks of NdFeB of
temperature stability and corrosion have now been successfully dealt with. The alloying of trace
quantities of additional metals to the NdFeB mix has allowed the production of materials able to
handle 200°C and at the same time offering increased resistance to corrosion.
Plating or coating after production offers maximum corrosion resistance in the most extreme of
applications. Over the past few years there has been much development in Injection or compression
molded magnetic materials offering easy manufacturing of complex shapes and magnetic pole
configurations to net shape, without additional machining. In the past, injected Ferrite was
successfully developed and today is in common usage. However it is the manufacture of bonded
NdFeB that offers the exciting mix of higher performance coupled with lower weight that is
expected to be commonly adopted by the automotive industry in the future.
Today bonded and injected NdFeB grades are available with high resistance to start up
demagnetization forces, allowing the material to easily replace Sintered Ferrite Arc segments in
motors. This is probably the largest application sector in the Automotive market, and bonded NdFeB
could offer both significant weight saving (and/or miniaturization), coupled to higher performance.

11
4. The Future
The Magnetic material industry will continue to develop new grades and materials to specifically suit
the automotive industry. This will allow the industry to meet the increasing pressure from
manufacturers to design more efficient, lower weight high performance components. As we enter the
21st century we can expect the total number of magnets per car to at least double if not treble in the
next few years.
5. Conclusions
Material selection in the automobile industry is an artful balance between markets, societal, and
corporate demands. The competition in the market of electrical and magnetic materials for
automotive applications is substantial. This is due to the size and value of the market. In the more
recent years the environmental concern has opened the need for lighter vehicle for lower fuel
consumption and also for the need of recycling. These recent pressures have opened the door for
introduction of new materials to the automotive market such as alternative metals. However there are
yet significant barriers in large scale use of these materials mainly due to the cost of the raw
materials or the large capital investment need for transformation of the forming processes. Therefore
the need for further research for suitable processes, properties and lower cost materials in this
lucrative industry is at its peak.

12
6. References
[1] Systematic approach on materials selection in the automotive industry for making vehicles
lighter, safer and more fuel–efficient, Mihai-Paul Todor, Imre Kiss University Politehnica
Timisoara, Faculty of Engineering Hunedoara, Romania. (Date Retrieved: April 29, 2018).
[2] Materials in Automotive Application, State of the Art and Prospects, A research gate
publication by Elaheh Ghassemieh University of Sunderland. (Date Retrieved: April 29, 2018).
[3] Materials used in automobile manufacture – current state and perspectives M. Wilhelm (Date
Retrieved: May 17, 2018).
[4] Material selection and design, Moonsub Shib 2007, 2008. (Date Retrieved: May 17, 2018).
[5] Recent development in aluminium alloys for the automotive industry, W.S. Miller A, L.
Zhuang a, J. Bottema a, A.J. Wittebrood a, P. De Smet b, A. Haszler c, A. Vieregge. (Date
[6] Magnesium and its alloys applications in automotive industry Mustafa Kemal Kulekci. (Date
[7] https://mech.utah.edu/composites_cars/ (Date Retrieved: May 21, 2018).
[8] Applications of composite materials in the automobile industry by praveengouda patil,
2009/10. (Date Retrieved: May 21, 2018).
[9] Michael F. Ashby, Materials selection in mechanical design fourth edition, butterworth
heinemann publication, October 2010. (Date Retrieved: May 22, 2018).

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