7 results about "Equivalent circuit" patented technology

The invention belongs to the technical field of batteries, and particularly relates to a method for evaluating performance states of automotive power batteries. Through performing second-order equivalent circuit modeling on automotive power batteries (including lead-acid batteries, nickel-metal hydride batteries, lithium ion batteries, fuel batteries, super batteries and the like), the performance states of the batteries (a state of charge (SOC) and a state of health (SOH)) are transformed to parameters of an equivalent circuit model. An impulse charging-discharging experiment result of each automotive power battery is handled by using a second-order exponential damping fitting method in Origin software, so that the parameters of equivalent resistance and equivalent capacitance in the power batteries are obtained. A database of the power battery model parameters and the battery performance states is established as the basis of evaluating the performance states of the batteries in an operating process of an automobile, so that the power management can be optimized, problems can be found timely, and accidents are avoided.

The invention discloses a battery hysteresis voltage characteristic and rebound voltage characteristic-based extended Kalman filter SOC estimation method. The method comprises the following steps of (1), collecting parameter information such as a voltage, a current, a historical SOC, an accumulated charging / discharging frequency N and the like in a current state; (2), building a three-order RC equivalent circuit model of a battery based on a hysteresis voltage characteristic and a rebound voltage characteristic of the battery; (3), establishing an SOC state equation based on an improved ampere-hour integration method; (4), based on the established state equation and an observation equation, continuously correcting an SOC value at a current moment according to an extended Kalman recursion principle, thereby enabling an estimated value to be gradually close to a real value; and (5), when an SOC error is smaller than 2%, ending an extended Kalman recursion process of the SOC. According to the scheme, the shortcomings that an open circuit voltage method cannot perform online estimation and an ampere-hour integration method has current error accumulation are overcome; the estimation precision of the battery SOC is improved; and online estimation of the battery SOC is realized.

The present invention relates to a method for evaluating the crosslink degree of a vulcanized sample in real time during a vulcanization process or diagnosing the electrical properties of the sample after the completion of the vulcanization process, and then determining an optimal vulcanization time and an optimal content of each constituent gradient of a composition for vulcanization that optimize the properties of the composition according to the vulcanization conditions, for the sake of improving the properties of the vulcanized sample prepared from a polymer by vulcanization at a high temperature.The method for determining an optimal vulcanization time and an optimal content of each constituent gradient of a composition for vulcanization that optimize the properties of the composition according to the vulcanization conditions includes: (a) measuring an impedance spectrum in a specific frequency range in the individual vulcanization condition; (b) approximating the measured impedance spectrum to an equivalent circuit model consisting of resistance and capacitance components; (c) determining a polymer resistance Rp (i.e., a value obtained by subtracting a real part of the impedance measurement at a maximum frequency from a real part of the impedance measurement at a minimum frequency, or the magnitude of a real part of the semicircle in a Nyquist diagram) from the determined parameters; (d) determining, as an optimal end point of vulcanization, a time point at which the increasing rate of the polymer resistance Rp rapidly slows down; and (e) determining the optimal content of each constituent ingredient of the composition for vulcanization when the polymer resistance Rp of the sample completely vulcanized is at its minimum.