Nyobolt, a UK battery company founded in 2020, develops lithium ion batteries with ultrafast charging, high power density and long life cycle. The battery uses innovative niobium-containing metal oxide anode materials.
Challenges: fast charging lithium battery
Lithium ion batteries are typically designed for optimal performance between 15 and 40 ºC. The materials used for the positive and negative electrodes and the lithium ion-containing electrolyte are the primary limiting factors for this operation. Under such optimal conditions, battery performance properties such as specific energy, specific power, cycle life, shelf life, and safety are maximized.
When such battery powered devices are used in high power regimes, such as rapid acceleration in an electrical vehicle (EV) or fast charging mobile phone batteries (charging the battery completely in less than one hour or partial charging greater than 80% of the battery capacity in 30 minutes or less), the temperature rises rapidly due to the heat generation from high currents (ohmic losses), thereby limiting the batteries ability to deliver sustained power or accept more charge.
Overheating the battery results in catastrophic failures due to thermal runaways, fires, and explosions. To prevent rapid changes in temperature, battery management systems that control the charging and discharging of lithium ion batteries shutdown the device operation.
To overcome this limitation, bulky thermal management systems are used to keep the operation temperature of the batteries within the optimal temperature. The weight of these systems typically reduces the range of EVs by 40-50%.
In addition, temperatures of 45 ºC or higher have an effect of reducing the cycle life of the cell due to the degradation of the interfacial layer between the electrode material and the electrolyte, called the solid electrolyte interface (SEI). This SEI layer, which is formed on the anode material surface, is responsible for the stable operation of a lithium ion battery, and the upper limit of 45 ºC exists because, at higher temperatures, the SEI layer tends to decompose, resulting in a drastic fade in cell capacity.
A similar reduction in the range of an EV also occurs in a low temperature environment, such as 10 ºC or below. In particular, use of EVs in freezing conditions causes a serious reduction in range. At low temperatures, chemical reactions within the battery proceed more slowly, and in freezing temperatures, lithium plating can occur on the surface of graphite anode.
In summary, EVs require lithium-ion batteries that can operate at high rates and wide temperature windows to improve performance, driving range, faster charging, and safety. Developing batteries that can meet these requirements is essential for the widespread adoption of EVs and the transition to a more sustainable transportation system.
Nyobolt Technology
Nyobolt develops lithium ion battery technologies that achieve record-breaking ultrafast charging, high power density, and wide range of operation temperatures based on the innovative niobium-containing metal oxide anode materials.
Nyobolt battery
The diagram below depicts the structure of a Nyobolt’s lithium ion battery cell.
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