Energy-based estimation method for health state of lithium battery

Abstract

The invention relates to an energy-based estimation method for the health state of a lithium battery. The method comprises the following steps: S1, defining SOH based on energy; s2, performing a full-interval SOC charge-discharge cycle test on the battery sample; s3, according to the energy released each time, obtaining a relation curve of the available energy along with the cycle index, calculating accumulated residual energy, and calculating SOH as a reference value by definition; s4, replacing ENK' in the linear curve with an original real curve actual value ENK, and finding a relational expression of energy and SOH in combination with a similar triangle principle; s5, on the basis of an original linear curve, improving the original linear curve to find a new curve capable of enabling the error of (E-E ') to reach a local minimum value, determining N values of different available energies through an interpolation method under the condition that part of data is known, and obtaining the new curve through upward translation of the linear curve according to the original energy ENK corresponding to the N values, and S6, substituting the adjusted curve into an energy and SOH relational expression to obtain SOH.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to an energy-based method for estimating the state of health of lithium batteries. Background technique [0002] With the rapid development of the economy, it has caused huge energy consumption in the society. In order to solve the social crisis of energy shortage and environmental pollution, it is urgent to develop new energy sources, and the research on new energy vehicles is also developing day by day. Vigorously developing new energy vehicles and building a safe, efficient, clean, economical and stable energy consumption structure are important measures to achieve sustainable social development. Lithium-ion batteries are widely used in the field of battery energy storage due to their significant advantages such as low self-discharge rate, high energy density, long cycle life, and no memory effect, and have become one of the key technologies for new ener...

AI Technical Summary

Problems solved by technology

So far, there are no strict regulations on the definition of SOH. At present, there are many ways to study battery SOH from various angles, and use its different characteristic parameters to characterize the health status of the battery, such as: capacity angle, internal resistance angle and power angle, etc., but these parameters cannot directly reflect the driving range of electric vehicles, so the present invention proposes a new method for estimating the state of health of the battery, which is mainly based on the energy parameters to characterize the state of health of the battery and then estimate the SOH. High feasibility and superiority

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