A physically meaningful equivalent circuit network model of a lithium-ion battery accounting for local electrochemical and thermal behaviour, variable double layer capacitance and degradation

This article provides a comparative analysis of various energy storage devices. A detailed review and analysis of molecular energy storage units is carried out, their main characteristics and parame-ters, as well as their application areas, are determined. The main types of molecular energy storage are determined: electric double layer capacitors, pseudo capacitors, hybrid capacitors. Comparison of the characteristics of various batteries is given. The parameters of various energy storage devices are presented. The analysis of molecular energy storage devices and accumulators is carried out. Ttheir advantages and disadvantages are revealed. It has been shown that molecular energy storage or double layer electrochemical capacitors are ideal energy storage systems due to their high specific energy, fast charging and long life compared to conventional capacitors. The article presents oscillograms of a lithium-ion battery with a voltage of 10.8 V at a pulsed load current of 2A of a laptop with and without a molecular energy storage device, as well as oscil-lograms of a laptop with DVD lithium-ion battery with a voltage of 10.8 V with a parallel shutdown of a molecular energy storage device with a capacity of 7 F and without it. The comparative analysis shows that when the molecular energy storage unit with a 7 F capacity is switched on and off, transient processes are significantly improved and there are no supply voltage dips. The dependenc-es of the operating time of a 3.6 V 600 mAh lithium-ion battery at a load of 2 A for powering mo-bile cellular devices with and without a molecular energy storage are given. It is shown that when the molecular energy storage device is switched on, the battery operation time increases by almost 20%.

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An Adaptive Estimation Scheme for Open-Circuit Voltage of Power Lithium-Ion Battery

Abstract and Applied Analysis ◽

10.1155/2013/481976 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6

Author(s):

Yun Zhang ◽

Chenghui Zhang ◽

Naxin Cui

Keyword(s):

Lithium Ion Battery ◽

Equivalent Circuit ◽

Open Circuit Voltage ◽

Adaptive Estimation ◽

Equivalent Circuit Model ◽

Lithium Ion ◽

Open Circuit ◽

Adaptive Scheme ◽

Power Battery ◽

Estimation Scheme

Open-circuit voltage (OCV) is one of the most important parameters in determining state of charge (SoC) of power battery. The direct measurement of it is costly and time consuming. This paper describes an adaptive scheme that can be used to derive OCV of the power battery. The scheme only uses the measurable input (terminal current) and the measurable output (terminal voltage) signals of the battery system and is simple enough to enable online implement. Firstly an equivalent circuit model is employed to describe the polarization characteristic and the dynamic behavior of the lithium-ion battery; the state-space representation of the electrical performance for the battery is obtained based on the equivalent circuit model. Then the implementation procedure of the adaptive scheme is given; also the asymptotic convergence of the observer error and the boundedness of all the parameter estimates are proven. Finally, experiments are carried out, and the effectiveness of the adaptive estimation scheme is validated by the experimental results.

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