Introduction to the Battery University (1/5)

Before we take a closer look at lithium batteries, let’s show one more interesting thing here: lead batteries still power electric boats on the Brno dam. Their disadvantage in the form of heavyweight becomes an advantage here: The heavy batteries at the bottom of the ship also serve as a ballast stabilizing the ship so that it does not overturn.

Different types of batteries - different properties

The lithium battery area itself contains many types that differ in their properties, life and price. Today, there is no universal type that would allow the use of a light, small and cheap battery with a high amount of energy, high performance and longevity, and therefore a different type of lithium battery is suitable for each application.

At Battery School, we will look at each application to understand which batteries are best for them. The graph below shows the specific battery energy in Wh / kg for an initial idea.

When choosing a battery system for a vehicle, it is then necessary to specify several basic criteria that will help with the selection of a suitable type of traction battery. Especially for public transport vehicles with no standard series production, there is a lot of room for adapting the vehicle to the requirements of a particular carrier.

The first determinant of the type of traction battery is the type of vehicle and its operation.

The battery, which serves as a range extender for partial trolleybuses, will not be suitable for a vehicle with a long range requirement, such as a long-distance electric bus, but may instead be ideal for a fast-charged electric bus at stops, end stations, etc.

On the other hand, a battery that would be used, for example, in an electric garbage truck, will not be entirely suitable for these applications, because it must travel the entire shift without the possibility of recharging.

An important aspect for choosing a suitable technology is also the service life, which results in later costs for battery replacement. Some lithium batteries, such as lithium titanate (LTO), have a large number of cycles and a calendar life and, when properly designed, will allow the same life to be achieved as the planned life of the entire vehicle. Additional batteries will allow all-day operation without recharging and the batteries will be charged when the vehicle is not moving, similar to personal electric cars.

Last but not least safety must also be taken into account. Even in this, the types of lithium batteries differ, so it is necessary to take into account the complexity of the design of the entire battery system.

An afterlife

A separate topic, which we will also address, is the disposal of batteries after they can no longer be used in their original application – the vehicle. Battery disposal and recycling is a burning issue today that is still open. The recycling and recovery of chemical compounds from batteries is still the subject of research by many scientists around the world. Research is not facilitated by the fact that lithium batteries differ in their chemical composition. The research is then based on the possibility of extracting the rare elements that lithium batteries contain, and it must be difficult to mine mostly in developing countries around the world.

Even after the battery has reached the end of its life in the vehicle, because it no longer has sufficient capacity, it can serve as a stationary source of energy. Compared to lead batteries, the degradation of lithium batteries is gradual – simply put, it is linear with respect to style of use and age, on the contrary, lead batteries have a clear calendar life, after which their capacity drops rapidly to zero, and their further use is no longer possible. On the contrary, the recycling of lead-acid batteries is well managed by their manufacturers, and almost all discarded lead-acid batteries can be recycled and thus reused.

 The secondary use of discarded lithium batteries, so-called second life, is a new worldwide topic. There are several pilot projects in the world where discarded batteries are used. In our country, for example, nano power uses discarded LTO batteries, which originally operated in AGVs (automatic handling robots), as an energy storage device in its stationary energy storage, which it uses to measure the capacity of new batteries. Here, energy is transferred from one battery to another, making it possible to use old batteries that could no longer be used in the original application and to save costs by significantly reducing the energy consumption required to charge the batteries before capacity measurement.