Study on closed loop charging strategy of battery based on Maas's law
In the process of battery charging, the influence of different charging methods on battery life is different. Traditional charging methods such as constant voltage charging, constant current charge, two phase charge, or three phase charge, these methods to a certain extent accelerate the aging of the battery. In this paper, based on the theory of Maas best charge curve and closed-loop control, a charging strategy is designed. The experimental results show that the designed charging strategy has a substantial improvement in the aspect of extending battery life and safety protection.
Study of Parameters Identification Method of Li-Ion Battery Model for EV Power Profile Based on Transient Characteristics Data
Power simulation of lithium ion battery through battery model is of great significance for dynamic response simulation, heat generation calculation and charge-discharge strategy development. The accuracy and applicability of the model become crucial. In order to demonstrate the battery transient characteristics more effectively, a novel identification method for parameters of the 2nd order RC equivalent circuit model was proposed. Based on the derived evolution law of battery transient characteristics under the continuous pulse excitation, four feature points are extracted for parameter identification in each cycle. The proposed method reduced the time cost of identification from 11796.88s to 0.06s while ensuring that the error of voltage doesn’t exceed 2.2mV. In order to verify the power profiles applicability of the proposed method, applicability analysis of power profile for different identification methods was carried out including the methods using different amount of data (4N points, 200 points, 6000 points) under unidirectional current pulse excitation (UCPE), bidirectional current pulse excitation (BCPE) and unidirectional voltage pulse excitation (UVPE). It was illustrated that the identification process using data of multiple cycles could significantly reduce errors, including maximum error and average error. What’s more, the proposed method under UCPE had the lowest maximum error of 0.420% in voltage simulation and −0.421% in the current simulation of power profiles. Compared with the conventional method (using 200 points of single pulse data for parameter identification), the proposed method can reduce the average voltage error and the maximum error by 62.5% and 11.8% respectively under the DST power profile.
New records of Grania (Clitellata, Enchytraeidae) in the Northeast Atlantic (from Tromsø to the Canary Islands), with descriptions of seven new species
Previous northeast Atlantic records of Grania have been mainly from Germany, southern Scandinavia, and the Atlantic shores of France, Spain and Ireland. They were referred to eight species, with one, G. atlantica, reported from the continental slope. We have examined various unpublished collections from sources spanning from the Canary Islands to the Norwegian Arctic. Apart from new information on morphology, taxonomy, and distribution of known species, we describe seven new taxa (G. canaria, G. fortunata, G. mauretanica, G. aquitana, G. vikinga, G. torosa, and G. papillinasus). The collection of G. papillinasus from 2630-2885 m represents a new depth record for Enchytraeidae. Twenty-five of the now 57 Grania species occur in the North Atlantic. The North Atlantic drift moderates sea temperatures along the northeast Atlantic coasts, probably facilitating the wide latitudinal range of some taxa, as well as actual dispersal within the region. A "chaetal index" (chaetal length : chaetal foot length) is proposed to differentiate L-shaped chaetae at the species level. Complex relationships within the "type 6 group" of Grania suggest that groupings established using certain combinations of penial, chaetal and spermathecal patterns may not be monophyletic. For a better phylogenetic resolution, additional morphological details of these and other characters are needed.