Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (6): 2326-2333.doi: 10.19799/j.cnki.2095-4239.2021.0099

• Energy Storage Test: Methods and Evaluation • Previous Articles     Next Articles

Health state estimation of lithium-ion batteries based on attention augmented BiGRU

Fan WANG(), Yongsheng SHI(), Boqin LIU, Yujie ZUO, Zheng FU, Jamsher ALI   

  1. School of Electrical and Control Engineering, Shaanxi University of Science&Technology, Xi'an 710021, Shaanxi, China
  • Received:2021-03-15 Revised:2021-05-13 Online:2021-11-05 Published:2021-11-03

Abstract:

Lithium-ion batteries' state of health (SOH) is the central concern of a battery management system. An accurate evaluation of SOH can ensure that batteries operate safely and reliably. However, in practice, it is difficult to measure capacity, which makes SOH estimation difficult directly. To obtain accurate SOH, this paper proposes an attentional improved bidirectional gated recurrent unit (BiGRU)-based SOH estimation method for lithium-ion batteries. Firstly, parameters such as voltage, current, and impedance are extracted from the charge-discharge curve of the battery, and the auto encoder reduces the dimensions to extract the features and reduce the redundancy between the data. Secondly, an attention mechanism is introduced to assign weight to input variables and highlight the characteristic quantities that play a key role in SOH estimation. Finally, the BiGRU is used to learn the mapping relationship between input variables and capacity and capture long-term dependence under capacity decay. The results of the University of Maryland battery datasets with different charging rates show that the proposed method can estimate SOH with high precision for different types of batteries, with a root mean square error of less than 1.1%.

Key words: lithium-ion battery, state of health(SOH), attention mechanism, auto encoder, bidirectional gated recurrent unit

CLC Number: