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Alternative Fuels for Transportation
10.3.2.5 Lithium-Based Batteries
Lithium is the lightest of all metals and presents very interesting characteristics from an electrochemical point of view. It allows very high thermodynamic voltage that results in high specific energy and specific power.
The two major types of lithium-based batteries are lithium-polymer and
lithium-ion.
10.3.2.5.1 Lithium-Polymer Battery
These batteries use lithium metal as the negative electrode and transition
metal intercalation oxide as the positive electrode. A thin solid polymer is
used as an electrolyte that offers improved safety and design flexibility. On
discharge, lithium ions formed as the negative electrode migrates through
the solid polymer electrolyte and are inserted into the crystal structure at the
positive electrode. On charging, the process is reversed. The major advantage of these batteries is the very low self-discharge rate and the drawback
is the relatively weak low-temperature performance due to the temperature
dependence of ionic conductivity.
10.3.2.5.2 Lithium-Ion Battery
Lithium-ion batteries use a lithiated intercalation material for the negative
electrode instead of metallic lithium, a lithiated transition metal intercalation oxide for the positive electrode, and a liquid organic solution or a solid
polymer as the electrolyte. On discharge lithium ions are released from the
negative electrode, migrate via the electrolyte and are taken up by the positive electrode. On charging the process is reversed. Lithium-ion batteries are
considered to be the most promising rechargeable batteries of the future.
Though this technology is at the developmental stage, it has gained wide
applications in EVs.
10.3.3 Motor Controllers
For the efficient operation of the EV it is necessary to control the vehicle
system components effectively so that energy is available all the time for
all the elements of the engine at the required level. In older vehicles, electric motor speed and torque were controlled by the variation of field and
rotor resistance of the DC motor. However, in recent days, to meet the tag of
zero emission vehicles, it is necessary to utilize the full advantages of EVs
by employing suitable control systems. To achieve that, every part of the
vehicle needs to be controlled by sophisticated electronics/computer control
systems.
Motor controller is a device or group of devices that serves in some predetermined manner the performance of an electric motor in an EV. It includes
manual or automatic means for starting and stopping the motor, selecting
forward or reverse rotation, selecting and regulating the speed, regulating
Alternative Fuels for Transportation
10.3.2.5 Lithium-Based Batteries
Lithium is the lightest of all metals and presents very interesting characteristics from an electrochemical point of view. It allows very high thermodynamic voltage that results in high specific energy and specific power.
The two major types of lithium-based batteries are lithium-polymer and
lithium-ion.
10.3.2.5.1 Lithium-Polymer Battery
These batteries use lithium metal as the negative electrode and transition
metal intercalation oxide as the positive electrode. A thin solid polymer is
used as an electrolyte that offers improved safety and design flexibility. On
discharge, lithium ions formed as the negative electrode migrates through
the solid polymer electrolyte and are inserted into the crystal structure at the
positive electrode. On charging, the process is reversed. The major advantage of these batteries is the very low self-discharge rate and the drawback
is the relatively weak low-temperature performance due to the temperature
dependence of ionic conductivity.
10.3.2.5.2 Lithium-Ion Battery
Lithium-ion batteries use a lithiated intercalation material for the negative
electrode instead of metallic lithium, a lithiated transition metal intercalation oxide for the positive electrode, and a liquid organic solution or a solid
polymer as the electrolyte. On discharge lithium ions are released from the
negative electrode, migrate via the electrolyte and are taken up by the positive electrode. On charging the process is reversed. Lithium-ion batteries are
considered to be the most promising rechargeable batteries of the future.
Though this technology is at the developmental stage, it has gained wide
applications in EVs.
10.3.3 Motor Controllers
For the efficient operation of the EV it is necessary to control the vehicle
system components effectively so that energy is available all the time for
all the elements of the engine at the required level. In older vehicles, electric motor speed and torque were controlled by the variation of field and
rotor resistance of the DC motor. However, in recent days, to meet the tag of
zero emission vehicles, it is necessary to utilize the full advantages of EVs
by employing suitable control systems. To achieve that, every part of the
vehicle needs to be controlled by sophisticated electronics/computer control
systems.
Motor controller is a device or group of devices that serves in some predetermined manner the performance of an electric motor in an EV. It includes
manual or automatic means for starting and stopping the motor, selecting
forward or reverse rotation, selecting and regulating the speed, regulating