Lithium ion battery SOH online estimation method
A lithium-ion battery and battery technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve the problems that the online estimation application cannot be realized, and the dynamic change characteristics of electric vehicles cannot be fully considered.
Pending Publication Date: 2020-11-20
XIAN UNIV OF TECH +1
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[0006]
The purpose of the present invention is to provide a lithium-ion battery SOH online estimation method, which solves the problem that the existing electric vehicle battery SOH estimation method uses capacity or internal resistance as the health index, cannot realize online estimation application, and the acquisition of filtering method parameters requires a fixed charging method. The discharge mode cannot fully consider the dynamic changing characteristics of the electric vehicle in the actual working process
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[0089] The data set used in the present invention comes from the lithium-ion battery test bed built by the NASA PCoE Research Center. The battery is a commercially available 18650Li-ion battery with a rated capacity of 2Ah. Lithium-ion cells (B0005, B0006 and B0007) were tested at room temperature through 3 different operating characteristics (charge, discharge and impedance). Charge in 1.5A constant current (CC) mode until the battery voltage reaches 4.2V, then charge in constant voltage (CV) mode until the charge current drops to 20mA.
[0090] The constant voltage charging voltage, current and time, and Li-ion battery capacity are extracted from the data. Such as Figure 7 Shown is the health indicator HI and the capacity comparison chart. It can be seen that there will be errors in the actual extraction process and measurement, and the error points need to be corrected. Therefore, this paper uses the Raida criterion method to correct the data. After the correction, it is...
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The invention discloses a lithium ion battery SOH online estimation method. The method specifically comprises the following steps: step 1, collecting voltage, current and time in a constant-voltage charging process of an electric vehicle battery and current, time and capacity in a constant-current discharging process in an offline manner; step 2, extracting the constant-voltage charging time adopted in the step 1 as a health index; step 3, preprocessing the health index data by adopting a Layda criterion; step 4, establishing a mapping relationship between the health indexes and the capacity by adopting a BP neural network algorithm; and step 5, carrying out online signal acquisition, extracting health indexes, c arrying out capacity estimation by using a BP neural network algorithm, and calculating a battery SOH value. According to the method, the problems that an existing electric vehicle battery SOH estimation method takes capacity or internal resistance as a health index, online estimation application cannot be realized, a fixed charging and discharging mode is needed for parameter acquisition of a filtering method, and dynamic change characteristics of the electric vehicle inthe actual working process cannot be fully considered are solved.
Description
technical field [0001] The invention belongs to the technical field of lithium batteries and relates to an online SOH estimation method for lithium ion batteries. Background technique [0002] Due to its high specific energy, high working voltage, wide temperature range, low self-discharge rate, long cycle life and good safety, lithium-ion batteries are widely used in electric vehicles and various fields, and gradually become the key and key to many important fields in the future. support. However, the performance degradation of lithium-ion batteries during use will affect the normal use of equipment and even cause serious failures. Usually, the state of health (SOH) of lithium-ion batteries refers to the ratio of the measured capacity to the rated capacity. Lithium-ion batteries SOH estimation can optimize the battery usage strategy and prolong the battery performance attenuation cycle; in addition, it can replace the bad battery in time, reduce the battery usage cost, and...
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Login to View More IPC IPC(8): G01R31/392G01R31/367
CPCG01R31/392G01R31/367Y02T10/70
Inventor 李宁何复兴马文涛李贺彭佩佩于若英
Owner XIAN UNIV OF TECH