How a lithium-ion battery works
Knowledge of how they work can be beneficial in assessing the dangers posed by lithium energy storage devices. Important to know: There is no “one” lithium battery. Instead, there are many different energy storage systems in which lithium is used in pure or bound form. A fundamental distinction is made between primary (non-rechargeable) and secondary (rechargeable) lithium-ion cells. In common parlance, the latter is usually meant when discussing lithium-ion batteries or accumulators. This article will teach you more about a lithium battery's functionality and chemical properties.
Functionality
A battery pack consists of several cells, depending on the required power. Each lithium-ion cell consists of a positive electrode (anode) and a negative electrode (cathode). Between them is an ion-conducting electrolyte. This ensures the transport of lithium ions between the electrodes during charging and discharging. Lithium-ion batteries are the best-known form of lithium energy storage device in which a liquid electrolyte is used.
Another critical component is the separator. It prevents direct contact between the anode and cathode, thereby preventing a short circuit. During discharge, lithium ions and electrons are released at the anode. Electrons flow through the external circuit and perform electrical work. At the same time, lithium ions migrate through the electrolyte and separator to the cathode.
When charging, this process is reversed. Depending on the system, the structure and materials used may vary across lithium-ion batteries. In a lithium-polymer accumulator, the electrolyte is incorporated into the polymer film's molecular framework. This allows us to dispense with a separate separator. Lithium-polymer energy storage can deliver only low discharge currents. Ensuring a lithium-ion battery safety while charging, such as a lithium-ion cabinet, is crucial for keeping your facility and employees safe.
However, the polymer film enables a flat design, so most energy storage is used in mobile phones and laptops. The thin-film lithium cell is an energy storage device in which an ion-conductive gas replaces the electrolyte. This enables the use of lithium metal and thus an extremely high energy density. This technique is currently an essential part of lithium energy storage research.
Chemical properties
While the German Federal Institute for Occupational Safety and Health (BAuA) regards lithium-ion batteries as products under the REACH regulation, the American Occupational Safety and Health Administration (OSHA) classifies batteries as mixtures. In practice, many companies prepare and make available safety data sheets for lithium batteries even without a legal obligation. These usually provide valuable information on battery storage and handling. However, details of chemical composition can often also be found, which provide information on the hazard. Lithium batteries can be divided into an anode, electrolyte fluid, and cathode.
As a rule, graphite (C) is used as the anode material, which must not be labelled under the CLP Regulation.
Many different materials are used for the cathode. The exact composition of the cathode material significantly determines properties such as lifetime, charging times, and performance. Iron, manganese, cobalt, and nickel are often used in the cathode.
The electrolyte fluid consists of an organic solvent and a conducting salt. While there is a large variety of possible solvents, lithium hexafluorophosphate (LiPF6) is almost exclusively used as the conducting salt.
Electrolyte liquid = organic solvent + conductive salt (LiPF6)
The exact chemical composition of the respective solvent mixture is usually a manufacturer's secret. By viewing various data sheets, however, you can get an overview of the components used. The flash points of the solvent elements range from + 160 ° C to sometimes below 0 ° C. This explains the thermal instability of a lithium battery.
The conductive salt contains fluorine (F), among other things. The released hydrofluoric acid (HF) in non-concentrated form can lead to various hazardous situations in a damaged lithium battery.
Related Content
The information provided on this page has been compiled carefully and to the best of our knowledge. However, DENIOS Ltd cannot guarantee or assume responsibility for the accuracy, completeness, or timeliness of the information, whether under contract, tort, or otherwise. Therefore, the use of the content is at the user's own risk. Always ensure compliance with local and applicable legislation.