The Faraday Institution launched the Battery Parameter eXchange (BPX), an open standard for physics-based lithium-ion battery models. The standard defines the battery parameters, the equations that use the parameters, and the reporting of experimental measurements used to validate the reported parameters.
The BPX standard additionally supports inclusion of experimental data used to justify the reported parameter values. Within the standard, parameters are stored in a human-readable, extensible, and easily-shared JSON file format. To enable easy adoption, tools to parse and validate BPX formatted files are provided in the BPX GitHub repository.
Two cells, currently available on the open market and which have been professionally parameterized, have been made available by About: Energy as examples and are included with the standard download. The examples are:
NMC_Pouch_cell: Li-ion battery with lithium nickel manganese cobalt (NMC) cathode in equal proportions (NMC-111). This type of cell is widely used in the battery market with high energy density and this particular cell is a pouch configuration.
LFP_18650_cell: Li-ion battery with lithium iron phosphate (LFP) cathode in a cylindrical cell 18650 format. This type of cell is becoming much more widely used trading energy density for longer life and greater thermal stability than NMC.
Physics-based battery models can deliver accuracy and insight into long-term performance in a wide range of scenarios. However, the complexity of physics-based models and lack of a common definition has limited their use to specialist teams within large companies, each creating their own modeling schemes that are difficult to compare with those of other companies.
The purpose of BPX is to reduce costs and time-to-market through a common definition of physics-based battery models that can be used widely across industry. BPX will make it easier for manufacturers and developers of all sizes to leverage the accuracy of physics-based models in a broad range of scenarios, which will reduce costs and stimulate innovation.
To meet the growing speed of change and demand from industry and society, improvements need to be made to battery performance, longevity, sustainability and safety. Years of advanced model development, a five-year investment in our Multi-scale Modeling Project, and the spin out of About:Energy sit behind the BPX standard. Its introduction will both speed up design and development cycles and reduce the need for expensive physical prototyping.—Professor Pam Thomas, CEO, Faraday Institution
Industry standards require maintenance and a clear technical, commercially informed roadmap. To this end the Faraday Institution is exploring the development of a Faraday Standards Forum, an industry/research partnership that could be launched in 2023 and that could own the roadmap for the maintenance and development of BPX.