Batteries
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leads to imbalances in the pack and can cause warranty issues (Pesaran,
et. al, 2003). To combat these issues, complete battery systems include a
battery thermal management system (BTMS). Generic BTMSs are comprised
of cooling, heating, and insulation elements that are adjusted to regulate each
specific battery. They are used not only to enhance the life span of the battery,
but also to keep the battery operating safely (Khan et. al, 2017). A simple way
in which EV owners can mitigate these temperature imbalance issues is to
park an EV in a location that helps to keep the battery cooler. For example, a
garage or other sheltered spot will help to prevent heating from the ambient
temperature on hot days. A more advanced option is to work towards the
further building of solar- powered charging stations (SPCSs), which help
keep the battery temperature down on a hot day by providing shade (i.e. the
solar panels) while also charging the battery.
The charging of a battery impacts its life span. An electrolyte between the
two electrodes conducts current, and conduction occurs when ions of the
electrodes are exchanged through the electrolyte. The exchange of the ions
occurs at the solid electrolyte interface (SEI) and forms an SEI layer. Material
builds up at this layer, creating internal resistance until the resistance is so
strong that ions can no longer be transferred, and the battery has reached
the end of its calendar life (Arcus, 2016). At high temperatures and at high
voltage, this process happens faster. Charging can occur at three levels: Level
1, level 2, and level 3, or DC fast charging. As the level increases, so does the
voltage, and the amount of time it takes to charge the vehicle decreases. The
faster the charge, the faster the charging will degrade the battery; therefore,
level 1 charging is healthiest for the battery and level 3 is the least healthy.
A test done on four BEVs, where two were charged using DC fast charging
and the other two were charged using level 2, showed a small but noticeable
difference, with greater battery capacity lost through DC charging (Shirk and
Wishart, 2015).
Batteries are equipped with a battery management system (BMS) that
ensures the battery is running safely and helps to protect it. Each charge
and discharge has an impact on battery life span. When a battery cell is
fully charged, it is at 100% state of charge (SoC). When a battery is fully
discharged, it is said to be at 100% depth of discharge (DoD) (Arcus, 2016).
Consistently taking a battery to 100% SoC or DoD is not good for the
health of the battery, so a BMS prevents the battery from reaching those
points. The BMS also “ensures that the energy of the battery is optimized
to power the product” and “that the risk of damaging the battery is minimal” (Hu, 2012).
Lastly, it should be remembered that maintenance costs on EVs are lower
because the battery and motor have fewer “wear- and- tear” parts, compared
to a conventional, internal combustion engine. Electric vehicles lack many
of the periodic maintenance items associated with conventional engines,
such as spark plugs, valves, belts, hoses, and catalytic converters (Gorzelany,
2019). In fact, there are entire systems – the carburetor/ fuel injection system,
63
63
leads to imbalances in the pack and can cause warranty issues (Pesaran,
et. al, 2003). To combat these issues, complete battery systems include a
battery thermal management system (BTMS). Generic BTMSs are comprised
of cooling, heating, and insulation elements that are adjusted to regulate each
specific battery. They are used not only to enhance the life span of the battery,
but also to keep the battery operating safely (Khan et. al, 2017). A simple way
in which EV owners can mitigate these temperature imbalance issues is to
park an EV in a location that helps to keep the battery cooler. For example, a
garage or other sheltered spot will help to prevent heating from the ambient
temperature on hot days. A more advanced option is to work towards the
further building of solar- powered charging stations (SPCSs), which help
keep the battery temperature down on a hot day by providing shade (i.e. the
solar panels) while also charging the battery.
The charging of a battery impacts its life span. An electrolyte between the
two electrodes conducts current, and conduction occurs when ions of the
electrodes are exchanged through the electrolyte. The exchange of the ions
occurs at the solid electrolyte interface (SEI) and forms an SEI layer. Material
builds up at this layer, creating internal resistance until the resistance is so
strong that ions can no longer be transferred, and the battery has reached
the end of its calendar life (Arcus, 2016). At high temperatures and at high
voltage, this process happens faster. Charging can occur at three levels: Level
1, level 2, and level 3, or DC fast charging. As the level increases, so does the
voltage, and the amount of time it takes to charge the vehicle decreases. The
faster the charge, the faster the charging will degrade the battery; therefore,
level 1 charging is healthiest for the battery and level 3 is the least healthy.
A test done on four BEVs, where two were charged using DC fast charging
and the other two were charged using level 2, showed a small but noticeable
difference, with greater battery capacity lost through DC charging (Shirk and
Wishart, 2015).
Batteries are equipped with a battery management system (BMS) that
ensures the battery is running safely and helps to protect it. Each charge
and discharge has an impact on battery life span. When a battery cell is
fully charged, it is at 100% state of charge (SoC). When a battery is fully
discharged, it is said to be at 100% depth of discharge (DoD) (Arcus, 2016).
Consistently taking a battery to 100% SoC or DoD is not good for the
health of the battery, so a BMS prevents the battery from reaching those
points. The BMS also “ensures that the energy of the battery is optimized
to power the product” and “that the risk of damaging the battery is minimal” (Hu, 2012).
Lastly, it should be remembered that maintenance costs on EVs are lower
because the battery and motor have fewer “wear- and- tear” parts, compared
to a conventional, internal combustion engine. Electric vehicles lack many
of the periodic maintenance items associated with conventional engines,
such as spark plugs, valves, belts, hoses, and catalytic converters (Gorzelany,
2019). In fact, there are entire systems – the carburetor/ fuel injection system,