Page 35 - PEN eBook July 2023

Smart Energy

Producing EV powertrain batteries has proven to be environmentally costly, but unfortunately,
only a few automakers are taking the problem seriously. The raw materials used in making these
batteries are lithium and its variants. These variants include cobalt nickel, manganese and several

other materials. The material dominating the market is cobalt manganese, which many electric
auto companies use. But on the other hand, Tesla uses a combination of lithium cobalt and
manganese. A few automakers are working on a new powertrain that will be cobalt-free; however,
cobalt still represents an essential mineral without which EV powertrains will be difficult to make.

Lithium-ion batteries are widely used in portable consumer electronics like smartphones and
laptops. They are also employed in EVs due to their higher energy density than lead-acid or nickel-
metal hydride batteries. This advantage enables automotive manufacturers to develop smaller
batteries without sacrificing storage capacity. Li-ion batteries also exhibit a high power-to-weight

ratio, high energy efficiency, high-temperature performance and low self-discharge. Additionally,
the various parts of Li-ion batteries can be recycled, making them an environmentally friendly
choice. The next section explores the workings of a basic Li-ion battery.

HOW DOES A Li-ION BATTERY WORK?

Li-ion batteries operate on the principle of electrochemical reactions, whereby the transfer of
electrons occurs between two electrodes, one of which is negatively charged while the other

is positively charged. The electrodes are immersed in a conductive electrolyte, facilitating the
movement of charged ions between them.

Li-ion battery charging
Li-ion cells have intercalation compounds characterized by a crystalline structure with layers
that allow the migration or deposition of lithium ions. When charging a Li-ion battery, the ions
travel from the positive to the negative electrode as they intercalate and await the next discharge
cycle.

The latest generation of batteries exhibits enhanced ion mobility, enabling faster charging without
the associated risk of overheating. In response, chipmakers have developed an array of integrated
solutions for Li-ion battery management that simplify the design of chargers. These companies
now offer silicon that enables engineers to design products capable of taking advantage of the
accelerated charging rates during the constant-current phase.

Li-ion battery discharging

During discharging, ions move from the negative electrode to the positive electrode via a liquid
electrolyte, while electrons flow from the negative electrode to the positive electrode through an
external circuit that delivers power to electronic devices. The combination of ions and electrons
at the positive electrode results in lithium deposition. Once all the ions have returned to the
positive electrode, the battery is fully discharged and requires recharging.

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