The Bottom-Up Cost Model for Lithium Batteries

Lithium batteries power our daily lives, from cordless vacuum cleaners to electric cars. They also store solar energy and provide instant backup power for critical devices during a power outage.

A lithium battery contains a non-aqueous electrolyte composed of alkyl carbonate solvents such as ethylene carbonate and propylene carbonate. This electrolyte is flammable and there is ongoing research to replace it with safer materials.

Benefits

Lithium batteries are lightweight and have a higher energy density which means they can fit into smaller spaces than lead acid. They also have a lower self-discharge rate and require less maintenance than other battery types. This makes them an excellent choice for material handling applications where space is at a premium.

In addition, lithium batteries are very stable as compared to other chemistries and do not suffer from memory effect. They are also highly recyclable and emit significantly fewer greenhouse gases than other batteries when they are discarded.

Unlike other battery chemistries, lithium batteries do not require a vented compartment and can be stored in any orientation or position. They also do not degrade over time when they are not being used and can be kept in service for up to 10 years.

A lithium-ion battery contains a special electrolyte solution that contains lithium ions in a liquid crystal structure that separates the positive and negative electrodes. The ions travel through the electrolyte to the positive electrode during charging and then back to the negative electrode during discharge. The BMS (Battery Management System) in the battery monitors a number of key aspects including the peak voltage of each cell during charge and prevents the battery from overcharging. It also monitors the cell voltage during discharge and when it drops below a pre-determined level it triggers an internal circuit that disconnects the battery.

Degradation Rate

The degradation rate of lithium-ion batteries varies depending on the operating conditions. The degradation rate of ion lithium battery a battery is influenced by several factors, including the temperature, charge and discharge cycles, and the use of high current rates. The degradation rate of a battery also depends on the age of the battery and the number of cycles it has been cycled.

The lumped particle diffusion model is a useful tool to characterize the performance degradation state of lithium-ion batteries. This method uses the partial differential equation to solve for a local particle state-of-charge variable SOC and a dimensionless spatial variable X ranging from 0 to 1. Using this, ohmic internal resistance, activation, and concentration losses can be characterized. Moreover, the performance degradation trends of these parameters can be correlated and analyzed.

A battery’s degradation rate is affected by the chemistry and structure of its electrodes. For example, the insertion and extraction of lithium ions into or out of the electrodes leads to capacity loss and a decrease in the coulombic efficiency of the cell. This degradation process is accelerated by high charging and discharging currents.

In this study, the results show that accurate OCV reconstruction and capacity estimation based on partial C/30 CC charging curves can be achieved for the investigated cell type, provided that SOC=20% is available. In addition, the accuracy of the estimated cathode capacity can be improved by using a larger SOC window.

Safety

Lithium batteries store a large amount of energy and can burn or explode if they are damaged or used incorrectly. They power many of the devices we use daily including laptops, cell phones, e-scooters, bicycles, toys, smoke detectors and even cars. These batteries can cause fires if they overheat, so it’s important to check for signs of overheating such as swelling, leaking or venting gas. Store lithium-ion batteries in a cool, dry place and always keep them away from heat sources like open flames.

Li-ion batteries also have a high risk of internal failure if they are exposed to excessive vibration, heat or freezing temperatures. The internal failure can occur when microscopic metallic particles come into contact with other parts of the battery, resulting in an electrical short circuit.

Most major lithium-ion battery manufacturers x-ray each individual cell during production as part of their quality control process. This helps to prevent internal failures caused by a variety of issues, such as bent tabs, crushed jelly rolls and uneven separators.

The best way to avoid a lithium-ion battery fire is to only purchase products and batteries with the UL mark. Always check that the charger is suitable for the product and that it is plugged in correctly. Never leave a charged lithium-ion battery unattended and always remove the battery from any device when it is not in use. If a battery does catch fire, use water to extinguish it.

Cost

The invention of lithium-ion batteries may have had one of the most significant impacts on human history, along with electric motors and nuclear power. They have enabled the e-mobility revolution as well as grid-scale energy storage. But they require more cost reductions to become fully competitive with ICE vehicles, especially for mass-market applications. To understand the determinants of the price trajectory of Li-ion batteries, BNEF has developed a high-resolution bottom-up model. The model takes into Portable lithium-ion battery account prospective developments in manufacturing technology and battery cell design, material prices estimates as well as expansions in the production capacity of LiB plants. It can also be used to investigate historical cost trajectories and their contributions.

The cathode of a lithium ion battery is the most expensive component, making up 40% of the total cell cost. Its formation and aging steps are the most energy-demanding of the battery’s manufacturing process. They are typically carried out at a slow charging rate to ensure dense and stable solid electrolyte interphase (SEI) on the anode surface.

The other components of the cell are less expensive, with the exception of the separator which is highly precision-manufactured to reduce losses. The anode and cathode are deposited on the separator in a very thin layer, allowing for the maximum amount of energy to be delivered per square inch of the cell.