Lithium ion battery internal health feature extraction method based on impedance spectrum

A lithium-ion battery and feature extraction technology, applied in the field of new energy research, can solve the problems of long EIS measurement time, inability to achieve online measurement, etc., and achieve the effect of short measurement time

Active Publication Date: 2018-01-19
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The present invention aims to solve the problem that in the existing method of estimating SOH through EIS analysis, the EIS measurement time is relatively long and online measurement cannot be realized

Method used

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  • Lithium ion battery internal health feature extraction method based on impedance spectrum
  • Lithium ion battery internal health feature extraction method based on impedance spectrum
  • Lithium ion battery internal health feature extraction method based on impedance spectrum

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specific Embodiment approach 1

[0019] Specific implementation mode one: refer to figure 1 and image 3 Specifically explain this embodiment, a method for extracting internal health features of lithium-ion batteries based on impedance spectroscopy described in this embodiment, the method includes the following steps:

[0020] Step 1, establishing a lithium-ion battery electrochemical impedance spectroscopy mathematical model;

[0021] Step 2, obtain the electrochemical impedance spectrum of the lithium ion battery by fast measurement of the electrochemical impedance spectrum of the lithium ion battery;

[0022] Step 3. Under the high, medium and low frequency bands, use the mathematical model of the electrochemical impedance spectrum of the lithium-ion battery established in the first step to identify the parameters of the electrochemical impedance spectrum of the lithium-ion battery in the second step, and obtain the lithium-ion battery’s electrochemical impedance spectrum. model parameters;

[0023] Ste...

specific Embodiment approach 2

[0028] Specific embodiment two: this embodiment is a further description of a lithium-ion battery internal health feature extraction method based on impedance spectroscopy described in specific embodiment one. In this embodiment, in step one, the electrochemical impedance of lithium-ion batteries Spectral mathematical models include single particle impedance model without considering SEI film, single particle impedance model considering SEI film, condensate impedance model and porous electrode impedance model,

[0029] Single particle impedance model without considering SEI film for:

[0030]

[0031] In the formula, R ct is the load transfer resistance, R ct =RT / (i 0 F), R is the gas constant, T is the temperature, i 0 is the positive exchange current density, F is the Faraday constant, κ is 1, j is an imaginary number, ω is the frequency, is the partial conductance of potential to concentration, C dl is the electric double layer capacitance; transfer function ...

specific Embodiment approach 3

[0041] Specific implementation mode three: refer to figure 2 Describe this embodiment in detail. This embodiment is a further description of the method for extracting internal health features of lithium-ion batteries based on impedance spectroscopy described in the first embodiment. In this embodiment, in step 2, the lithium-ion battery The specific process of obtaining the electrochemical impedance spectrum of the lithium-ion battery is as follows:

[0042] Input a transient voltage signal to the lithium-ion battery, measure the current transient response curve of the lithium-ion battery, obtain the analytical function according to the measured transient response curve, and perform Laplace transformation on the analytical function, according to the transformed s-domain The input signal above and the output signal of the transient response curve are used to obtain the electrochemical impedance spectrum of the lithium-ion battery.

[0043] In this embodiment, during the aging...

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Abstract

A lithium ion battery internal health feature extraction method based on an impedance spectrum, and relates to the new energy research field; an existing method uses an EIS to analyze and estimate a SOH, wherein the EIS is long in measuring time, and cannot realize online measurements; the lithium ion battery internal health feature extraction method comprises the following steps: building a lithium ion battery electrochemistry impedance spectrum mathematics model; fast measuring a lithium ion battery electrochemistry impedance spectrum, and obtaining the lithium ion battery electrochemistry impedance spectrum; using the lithium ion battery electrochemistry impedance spectrum mathematics model to identify the lithium ion battery electrochemistry impedance spectrum parameters respectively under high, medium and low frequency stages, thus obtaining the lithium ion battery model parameters; periodically measuring the electrochemistry impedance spectrum of the aged lithium ion battery, using the lithium ion battery electrochemistry impedance spectrum mathematics model to identify the lithium ion battery electrochemistry impedance spectrum parameters of the aged lithium ion battery, thus obtaining the model parameter changing rules in the lithium ion battery aging process, and serving as the features that evaluate the battery health states. The lithium ion battery internal health feature extraction method is used for evaluating the battery health states.

Description

technical field [0001] The invention relates to a health feature extraction method of a lithium ion battery, belonging to the field of new energy research. Background technique [0002] Lithium-ion batteries have outstanding advantages such as high voltage, high energy density, good cycle performance and no memory effect, and have been widely used. In the research of lithium-ion batteries, Electrochemical Impedance Spectroscopy (EIS) technology is widely used. Electrochemical Impedance Spectroscopy is also called AC Impedance Spectroscopy. The interface reaction, charge transfer, diffusion and other processes are effectively decoupled, and its measurement and analysis techniques are widely used in the description of battery characteristics, which can then analyze the battery state and improve battery preparation. EIS technology provides a basis for judging battery health status assessment, but currently it is mostly used to qualitatively analyze the speed of internal batter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/36
Inventor 吕超刘海洋丛巍张滔
Owner HARBIN INST OF TECH
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