What You Need to Know About Lithium-Ion Battery Degradation
Lithium-ion batteries (LIB) are an advanced, rechargeable battery that have long supported portable consumer electronics like phones, laptops and tablets. Their high power-to-weight ratio and energy efficiency make them ideal for wireless devices, and now this same technology is now being applied in mainstream transport.
LIB technology has been revolutionary in the world of electric vehicles as it has the highest energy density of any available battery and requires relatively low maintenance. Additionally, different compounds of lithium-ion batteries have different characteristics, meaning that batteries with higher capacity and voltage will likely contain different active materials than those with less. The higher amount of lithium in a battery means the larger capacity it will have, which is useful for machines like EVs that require higher power levels to run.
Luckily for both consumers and OEMs, the increasing demand for LIBs is quickly driving down their cost. However, the degradation and ultimate lifecycle of these batteries is a primary concern when it comes down to lifecycle costs and measuring carbon footprint.
Why is lithium-ion technology used for electric vehicle batteries?
Li-ion batteries are made up of three essential components: the positive and negative electrodes, cathode and anode, and the chemical layer known as the electrolyte. The cathode, typically lithium cobalt oxide, acts as the source of lithium ions and determines the battery’s capacity and voltage.
While charging, lithium ions are separated from the cathode and move to the graphite anode where they are temporarily stored, resulting in a charged battery. As the discharge cycle commences, however, this process reverses. Lithium ions in the anode lose their electrons, causing a current to run through the phone’s circuit and keep it powered. At the same time, the electron-less ions move through the electrolyte, returning to their place in the cathode, and resulting in a dead battery.
A major benefit to using LIBs over other rechargeable batteries, like nickel-cadmium or nickel-metal-hydride, is their ability to store a high level of energy in a relatively small amount of mass. This makes them ideal for applications greater than just portable consumer electronics, especially those where weight is an important consideration, like airplanes. Additionally, lithium-ion batteries don’t suffer from a memory effect like Nickel-Cadmium and Nickel-Metal-Hydride batteries do. This can be extremely detrimental to nickel-based batteries as it causes them to function at lower capacity when they are only partially discharged.
This is not to say that lithium-ion batteries are without fault. Unfortunately, lithium-ion batteries have their weaker points as well. Their lifecycles are contingent on external stress factors, such as storing conditions and operating temperature. These factors can quickly deplete the battery’s performance, capacity and power, resulting in a shorter working life. Along with battery degradation, inability to control these higher temperatures can lead to thermal runaway and combustion, posing a grave safety concern for users. For these reasons, a good thermal management system is essential for the optimal operation of lithium-ion technology. By keeping working temperatures between the range of 208 to 288 Kelvin, battery life can be prolonged and the effects of degradation can be reduced.
Are EV batteries a sustainable alternative for ICE vehicles?
While it is largely indisputable that EVs are more environmentally friendly than traditional ICE vehicles, this doesn’t mean they have no environmental impact at all. Electric vehicles leave a significant carbon footprint, namely in their manufacturing and charging. Throughout a lifecycle, EVs emit 33 percent less greenhouse gases and 93 percent less carbon monoxide than ICEVs, however, electric vehicles emit 273 percent more sulfur oxides into the atmosphere due largely to electricity generation.
The fact of the matter is, until electric grids go green across the board, electric vehicles cannot truly be a zero-emissions solution. An EV charged and driven in the United States today, where 60 percent of electricity is sourced from fossil fuels, will have a much harsher effect on the environment than an EV driven in Costa Rica, where 95 percent of energy produced is renewable.
Despite this, EVs are still a leading alternative to ICE vehicles. As the average grid in the United States consists of both fossil fuels and renewable energy sources, charging EVs with electricity will always be favorable to filling ICEs with nonrenewable fuel. This outlook is even more promising going forward, as more coal plants around the country are closing due to a greater push toward natural gas and renewable energy plants.
Another major challenge is the collection of raw materials for EV batteries. Lithium-ion batteries require elements like lithium (of course), cobalt and graphite for their production, and the extraction methods for these elements can be far from eco-friendly. Cobalt mining happens primarily in the Democratic Republic of Congo, where inadequate waste management leads to toxic mineral tailings and slags leaching into surrounding ecosystems and putting the population at risk – whereas lithium extraction is done mostly from saline groundwater in Chilean salt flats. Dissolved lithium is found naturally in these reservoirs, and is removed by pumping the brine to the surface using large amounts of water. This is a major contributor to the 56 percent more water resources used in an average EV lifetime compared to ICEVs.
Decomposition or recycling – which is the better solution?
After cycling through the stages of manufacturing and years of operation, comes an ultimate end-of-life for all EVs. Lithium-ion batteries cannot be disposed with regular waste, as they can cause a lot of damage to the environment if they end up in a landfill. When broken down, the cobalt inside LIBs can be very harmful even in very small quantities. If batteries are broken down in a landfill, these toxic metals will inevitably leak out posing the risks of contamination and fire.
The good news is that 50 percent of materials in lithium ion batteries can be recycled and reused. Valuable materials like nickel, cobalt and lithium can be recovered from spent batteries and used in new ones, leading to a drop in price and carbon intensity of battery production overall.
Despite the promising potential, however, the practice of lithium-ion battery recycling is not where it could be. On average, less than 5 percent of LIBs end up being recycled. Recycling plants are very costly to build and often lack the technology to undergo the complex process of breaking down the batteries. As lithium is a highly reactive element, these batteries must be handled properly to avoid short-circuiting or immediate combustion.
The thing is – now that the electric vehicle industry is really taking off, large-scale recycling solutions will need to quickly catch up. While individual consumers can easily look to online directories for their nearest recycling plant that welcomes lithium-ion batteries, immediate progress needs to be made to match the influx of EVs being purchased that will ultimately meet their end-of-life.
The bottom line
There are many factors to consider when it comes to making EVs more sustainable at every life stage. When broken down from raw material extraction to vehicle disposal, is clear to see that EV’s zero-emissions claim is really only true in operation.
Nonetheless, the amount of fossil fuels spared in comparison with ICE vehicles is not to be understated. Electric vehicles remain the leading solution for combatting climate change within the transport sector, and will continue to get even greener as research and funding into LIB recycling improves.
If you’re interested in learning more about how the integration of electric vehicles could impact the day-to-day operations of your fleet, schedule a demo with a member of our analytics team.