What are the components of an electric vehicle battery? 

Electric vehicle batteries have been called the “heart” of EVs due to its vital function of distributing electrical power to the various systems of an electric car. It also has the capability of storing energy for your next drive.

EV batteries are just as complex as the human heart. You cannot just define EV battery components as the physical parts of the battery. Perhaps, even more important are the chemical compositions of these components, the reactions of which generate electrical energy.

What are EV batteries made of?

When discussing EV battery components, the focus is on the chemical composition and physical parts that comprise EV battery cells. These cells are then combined into modules, which are assembled into EV battery packs. We shall be focusing on the components of lithium-ion EV batteries. 

An EV battery has four major components: the positive electrode called the cathode, the negative electrode called the anode, a micro-permeable separator which keeps these two electrodes apart, and an electrolyte (a lithium salt solution called lithium hexafluorophosphate). The cathode is made out of lithium, manganese, nickel, and cobalt. The anode is commonly made out of graphite but, like the cathode, it also contains lithium.

When discharging EV batteries while driving, electrical power is generated by the flow of lithium ions from the cathode to the anode. The reverse happens during battery charging wherein lithium ions flow from the anode to the cathode, so that the electrical energy gets stored.

How long does an EV battery last?

The average EV battery lifespan is between 10 and 20 years, although they can go longer with proper care and usage of both the vehicle and the battery.

Expect degradation of the battery to occur with time and aging, storing your vehicle in extreme temperatures, and frequent use of direct chargers.

How are EV batteries manufactured?

Manufacturing EV batteries is a complex and intensive process that requires intricate assembly and strict testing and quality control. The first to be manufactured are the individual cells of the electric vehicle batteries, in the layout mentioned above. These components are then encased in a metal housing. Tests are conducted on each cell to detect electrolyte leaks and internal moisture seepage.

Depending upon the model of the EV, these batteries are combined in another housing to form modules. The module housing protects the cells from external vibrations and shocks. Finally, these modules are assembled into battery packs, which are then installed into the electric vehicle.

The Nissan Leaf, for example, has 48 modules in its battery pack, with each module containing four cells. Thus, the Nissan Leaf has 192 EV battery cells with a 24 kWh capacity.

What components help improve EV battery performance?

There are some EV battery components that can be added to help improve its performance.

Busbars

A battery busbar helps distribute electric current from the EV battery to different parts of the vehicle. They do this by collecting electricity from incoming feeders and dispatching them to outgoing feeders.

Laminated busbars, meanwhile, have modern designs that are simpler and faster to assemble, save space, more reliable, and more effectively dissipates heat. 

EV busbars also help prevent overheating due to the heat generated in the battery.

Cell Contacting System

Cell contacting system technologies help batteries with different module designs to have evenly distributed current density.

These can come in useful as it supports cylindrical, pouch, and prismatic batteries, as well as varying module sizes and configurations.

How much does an EV battery cost?

After an EV battery has run out its lifespan, they will need to be replaced, the cost of which concerns many vehicle owners. 

EV battery packs used to have an average cost of $5,000, with certain car models having batteries costing as much as $15,000.

Thankfully, a dramatic reduction in EV battery cost has been observed during the past decade. At present, the average price of a kilowatt-hour (kWH) – the standard measure of EV battery price – has dropped from $1,160 per kWh in 2010 to $128 per kWh. It is projected that the price will drop even further, stabilizing at $90 per kWh by 2031.

Are EV batteries sustainable?

Sustainable EV batteries are largely dependent upon their chemical compositions, especially the valuable metals found in the cathode. Lithium is abundant with a global total of around 86 million tonnes.

However, there may be shortages for nickel and cobalt, mined in the Democratic Republic of Congo. There are also concerns about the toxicity of cobalt and the detrimental effects it has on the health of miners, including child workers.

Future EV battery technology hopes to eliminate nickel and cobalt from the cathode. One proposed method is using small amounts of other metals while retaining the lithium cobalt oxide crystal structure of the cathode. 

Another proposed approach is the use of disordered lithium-rich rock salts which allows for the easy flow of ions between the cathode and anode, but requires a more abundant metal (manganese) to stabilize the reaction instead of nickel or cadmium.

Are EV batteries safe?

EV battery design–from a single cell to a battery pack–seeks to ensure safety. While they are relatively safe, there have been reports of batteries catching fire. 

EV batteries may be fire hazards because of the use of electrolytes that are volatile and highly flammable in high temperatures. As such, EV batteries come with an active cooling system to prevent overheating and fire.

Another potential source for fire is damage to the separator. If the separator breaks in an accident, it can cause physical contact between the cathode and anode, resulting in a short circuit. The cathode ends up undergoing rapid discharge which overheats the electrolyte, leading to a fire.

EV battery research is looking into the development of solid-state batteries which eliminates the use of flammable liquid electrolytes and can endure high temperatures. Elimination of cobalt also improves the stability of the battery, so that there is lesser potential for fire. 

Finally, blade batteries are being produced which contain lithium-iron phosphate blocks for the cathodes. These are much cheaper than current lithium-ion varieties and are less prone to overheating.

EV battery components are not only vital for the proper functioning and energy distribution in an electric vehicle. With the right components, safety while driving can be assured.