Rechargeable Energy Storage Systems for Plug-in Hybrid Electric Vehicles—Assessment of Electrical Characteristics

Abstract

Abstract:In this paper, the performances of various lithium-ion chemistries for use in plug-in hybrid electric vehicles have been investigated and compared to several other rechargeable energy storage systems technologies such as lead-acid, nickel-metal hydride and electrical-double layer capacitors. The analysis has shown the beneficial properties of lithium-ion in the terms of energy density, power density and rate capabilities. Particularly, the nickel manganese cobalt oxide cathode stands out with the high energy density up to 160 Wh/kg, compared to 70-110, 90 and 71 Wh/kg for lithium iron phosphate cathode, lithium nickel cobalt aluminum cathode and, lithium titanate oxide anode battery cells, respectively. These values are considerably higher than the lead-acid (23-28 Wh/kg) and nickel-metal hydride (44-53 Wh/kg) battery technologies. The dynamic discharge performance test shows that the energy efficiency of the lithium-ion batteries is significantly higher than the lead-acid and nickel-metal hydride technologies. The efficiency varies between 86% and 98%, with the best values obtained by pouch battery cells, ahead of cylindrical and prismatic battery design concepts. Also the power capacity of lithium-ion technology is superior compared to other technologies. The power density is in the range of 300-2400 W/kg against 200-400 and 90-120 W/kg for lead-acid and nickel-metal hydride, respectively. However, considering the influence of energy efficiency, the power density is in the range of 100-1150 W/kg. Lithium-ion batteries optimized for high energy are at the OPEN ACCESSEnergies 2012, 5 2953 lower end of this range and are challenged to meet the United States Advanced Battery Consortium, SuperLIB and Massachusetts Institute of Technology goals. Their association with electric-double layer capacitors, which have low energy density (4-6 Wh/kg) but outstanding power capabilities, could be very interesting. The study of the rate capability of the lithium-ion batteries has allowed for a new state of charge estimation, encompassing all essential performance parameters. The rate capabilities tests are reflected by Peukert constants, which are significantly lower for lithium-ion batteries than for nickel-metal hydride and lead-acid. Furthermore, rate capabilities during charging have been investigated. Lithium-ion batteries are able to store about 80% of the capacity at current rate 2I t , with high power cells accepting over 90%. At higher charging rates of 5I t or more, the internal resistance impedes charge acceptance by high energy cells. The lithium titanate anode, due to its high surface area (100 m 2 /g compared to 3 m 2 /g for the graphite based anode) performs much better in this respect. The behavior of lithium-ion batteries has been investigated at different conditions. The analysis has leaded us to a new lithium ion battery model. This model will be compared to existing battery models in future research contributions.

Comparative Study of Surface Temperature Behavior of Commercial Li-Ion Pouch Cells of Different Chemistries and Capacities by Infrared Thermography

“…Titanate based anode has a higher electrical conductivity and a bigger surface area, thus, it shows lower impedance compared to graphite anode (see Figure 2 and Table 1). One of the reasons behind this variation is the distinction of solid-electrolyte interface (SEI) layer formation and the thickness characteristics between graphite and tianate anodes [3,26]. Thus, the net heat generation in the LTO cells is much lower, which makes the LTO cell a potential candidate for a cell with higher thermal safety, even during very fast charging (within less than 30 min).…”

“…A growing number of electric vehicles (EV) and hybrid electric vehicles (HEV) in the present market depicts the rapid growing demand [1][2][3]. Being of superior performance in terms of high power and energy density, EV and HEV manufacturers largely depends on lithium-ion batteries as the rechargeable energy source nowadays.…”

Design and use of multisine signals for Li-ion battery equivalent circuit modelling. Part 2: Model estimation

“…The ECM parameters should therefore also be a function of current magnitude or C-rate and as well as temperature. In [13] an ECM is estimated whereby the circuit parameters for each of the PPC pulses are included in a 3D look-up table for interpolation and simulation.…”

Design and use of multisine signals for Li-ion battery equivalent circuit modelling. Part 1: Signal design

“…In practice however, an ECM based on a single charge and discharge pulse is used to represent the battery dynamics at that particular SoC and battery temperature [2,3,4]. In contrast, the work in [5] presents a current dependent ECM whereby the model estimated for all the pulses is included, and therefore the ECM parameters are a function of current, SoC and battery temperature.…”