Hybrid energy storage systems

Some experimenters have combined battery storage and hydrogen storage to see if there are any advantages to such a hybrid storage method. 

For instance, where BSPMs are set up for normal battery charging duty, a diversion shunt is added so that when the batteries are fully charged, the electricity from the solar panel is diverted to the electrolyzer to produce hydrogen. Simple types of shunt devices that are not particularly energy efficient when solely used for charging in a regular BSPM system are, in this system, quite efficient. 

A BSPM system can incorporate hydrogen production in a number of different configurations. A basic hybrid energy storage system requires several 12 / panels with an approximate 10 amp output. These panels are connected in parallel with a diversion controller. To operate with the higher voltage and to use it efficiently, the system would include a bank of three electrolyzers connected in series (bipolar connection) that will use four volts each. This will be discussed in more detail at the end of the Electrolyzers chapter. 

With a battery and gas storage system, you can have the advantages that each technology provides, and have a base for making the transition to a battery-free hydrogen system in the future. 

The basic energy producing unit of a photovoltaic power generating system is the photovoltaic or solar cell. Solar cells can be made from a variety of different materials, however the silicon solar cell is the most common, well developed, and readily available, so it is what we will discuss here. 

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S. R. Vosen and J. O. Keller, Hybrid energy storage systems for stand-alone electric power systems optimization of system performance and cost through control strategies, Int. J. of Hydrogen Energy, 24 1139-1156 (1999). 

Maday, J.D., Brouwer, )., and Samudsen, G.S. (2007) Dynamic modeling of hybrid energy storage systems coupled to photovoltaic generation in residential applications. /. Power Sources, 163, 916-925. 

Zhou K Lu W. Self-sustainable off-grid wind power generation systems with hybrid energy storage. In 37th Annual Conference on IEEE Industrial Electronics Society (IECON 2011) 7-10 November 2011 Melbourne, VIC IEEE pp. 3198-3202. DOL10. 1109/IECON. 2011. 6119822. 

The DLCs provide a higher power density than the other electrochemical energy storage systems. They are often used in hybrid systems, in parallel with batteries or fuel cells, to improve the power performance and efficiency. 

Raiser S. General Motors Corporation. Hybrid fuel cell system with battery capacitor energy storage system. WO patent/2006/065364. 

The main issues of hybrid propulsion systems are discussed in this chapter, drawing attention to basic characteristics of power train components and aspects of energy management within each hybrid configuration. The main characteristics of electric drives are described in Sect. 5.2, different types of electric energy storage systems are analyzed in Sect. 5.3 and Sect. 5.4, while different configurations of hybrid electric vehicles are discussed in Sect. 5.5, with particular reference to fuel cell propulsion systems (Sect. 5.5.4). 

The experimental results discussed in this case study are obtained on a fuel ceU power train installed on a laboratory test bench. It is constituted by a 3.5 kW electric drive connected in hybrid configuration to a 2 kW PEM fuel cell system (FCS) and an electrical energy storage system (lead batteries). The main technical specifications of the FCS are reported in Table 6.1, whereas its scheme is shown in Fig. 6.1 [1, 2]. 

The general theme of electric vehicles is covered in Chap. 5, with particular reference to hybrid vehicles that adopt both fuel cells and batteries/supercapacitors as power sources. The analysis of possible hybrid configurations is presented together with a review of different types of electric energy storage systems. 

Battery pack development for electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) includes many of the same considerations involved in the development of battery packs for hybrid electric vehicles (HEVs). Typical Li-ion battery packs, also called rechargeable energy storage systems (RESS), generally include four main components (1) lithium-ion battery cells, (2) mechanical structure and/or modules, (3) battery management system (BMS) and electronics, and (4) thermal management system. 

FreedomCAR Electrical Energy Storage System Abuse Test Manual for Electric and Hybrid Electric Vehicle Applications... 

SAE J2464, Electric and Hybrid Electric Vehicle Rechargeable Energy Storage System (RESS) Safety and Battery Abuse Testing... 

Determination of the Maximum Available Power from a Rechargeable Energy Storage System on a Hybrid Electric Vehicle (SAE J2758)... 

See www.hrbridrive.com/hybrid-transit-bus.asp and www.hybridrive.com/lithium-ion-energy-storage-system.asp. 

N. Omar, Assessment of Rechargeable Energy Storage Systems for Plug-in Hybrid Electric Vehicles. PhD thesis, Brussels, September 2013. 

When the power demand of a fuel-ceU hybrid system is very high, the peak power will be supplied by the energy storage system. The fuel cell will be operated on average power, which is lower than the peak power. In comparison with a pure fuel-cell system, the size of the fuel cell could be reduced, thus reducing costs [10]. 

Normally, a fuel cell needs some time to reach the operating temperature after start-up. During this heating procedure, the power output of the fuel cell is limited. To cover the power consumption of the auxiliary components, and also the power demand of the load, the fuel cell has to be hybridized with an energy storage system [11]. 

It was shown that in a series fuel-cell hybrid, the fuel cell and the energy storage system are coimected via a DC bus. This coimection can be done actively or passively... 

The main characteristics of a passive fuel-cell hybrid and an active fuel-cell hybrid are shown in Table 36.2. Especially the voltage level of the fuel cell is very important, since a too low fuel cell voltage causes catalyst corrosion [19]. If the fuel cell and the energy storage system are coupled directly in the case of the passive hybrid, voltage limitation for degradation protection is not possible. 

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