Scientists must often ask themselves, compared to what? How do we compare the results we generate in the laboratory with those obtained by others? How do our theoretical calculations compare with experimental data?
Answering these questions is especially crucial for researchers and developers of lithium-ion batteries. Invented four decades ago, lithium-ion batteries now work with most portable electronic devices, such as laptops and power tools. They are also being developed to meet the high demands of energy storage to power electric vehicles and power grids. New designs with different electrode and electrolyte compositions, the two key components of the battery, are constantly online.
To badess whether an innovation in electrodes or electrolytes is actually an improvement requires comparing it with other test results. However, there is no "one size fits all" standard for battery tests. The methods for testing batteries can vary widely.
Argonne battery researcher Ira Bloom notes: "Industrial engineers and researchers from academic and government laboratories often design their own procedures to characterize lithium-ion batteries based on the application of battery technology. Comparing any technological innovation is extremely complicated. "
A team from the Argonne National Laboratory of the Department of Energy of the United States (DOE), the University of Warwick, OVO Energy, the National Institute of Energy of Hawaii and Jaguar Land Rover has reviewed the literature on the various methods used around the world to characterize the performance of lithium. ion batteries to provide information on best practices.
Normally, battery researchers use three parameters to define electrochemical performance: capacity, open circuit voltage and resistance. The capacity is a measure of the total charge stored in a battery. Open circuit voltage is the available voltage of a battery without current flow. Represents the maximum voltage of the battery. Resistance is the degree to which the component materials impede the flow of electrical current, resulting in a voltage drop.
The problem is that, depending on the application of the battery, researchers can measure these parameters under different test conditions (temperature, discharge speed, state of charge, etc.) and, therefore, obtain a different useful life. Battery. The resistance of the battery, for example, can be measured with direct or alternating current.
"It's complicated," observes Anup Barai, principal investigator and principal investigator at the University of Warwick. "The suitability of a test depends on what the researcher is studying, and our review provides guidance on the most appropriate test method for a given situation." To that end, the team has produced an easy-to-use table that compares eight test methods, including the necessary main equipment, the information generated, and the advantages and disadvantages of each.
"Our hope," adds Bloom, "is that our results may one day lead to more reliable comparable methods for testing lithium-ion batteries adapted to different applications."
The study, entitled "A comparison of methodologies for the non-invasive characterization of commercial Li-ion cells", appeared recently in the online version of the journal. Advances in energy and combustion science.
Modeling based on data and estimation of the properties of the lithium-ion battery
Anup Barai et al, a comparison of methodologies for the non-invasive characterization of commercial lithium ion cells, Advances in energy and combustion science (2019). DOI: 10.1016 / j.pecs.2019.01.001
Battery performance evaluation: Compared to what? (2019, May 9)
recovered on May 9, 2019
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