Battery Pack Energy Requirements

In Fig. 5.20, the scheme for the configuration of a solar vehicle is reported. The DC-DC converter is required to adapt the voltage generated by the solar system to the voltage range proper of battery pack and electric drive. The converter is mono-directional because no energy flux goes from the battery and motor drive toward the solar panel [3, 4]. 

The simultaneous utilization of FCS and battery within a fuel cell propulsion system can be accomplished by two basic ways (i) the battery pack can be minimized (but not eliminated as in full power) assigning the role of generating most energy required by the load to the FCS (soft hybrid configuration), (ii) the FCS can be sized to provide the base load, i.e. a power value close to the average power of the expectable road mission (hard hybrid configuration), while larger battery pack are necessary to satisfy the dynamic requirements. 

As previously discussed (Sect. 5.5), the battery pack of a fuel cell power train can be either minimized assigning the role of generating most energy required by the load to the fuel cell stack (soft hybrid), or sized in order to provide all dynamic requirements of the vehicle allowing the utilization of a smaller FCS (hard hybrid). 

The MG A energy per analysis requirements may threaten the compactness of a battery-operated unit, even if the ambitious goal of 1 J per analysis is met, because a lithium battery pack capable of 24 h of analyses repeated every 4 s would occupy a volume of 50.7 cm equivalent to a 3.7-cm cube [14], but would still be acceptable for hand-held analyzers. A volumetric reduction by factor of 4—6 may be achievable by the use of metal hydride sources of Hj for fuel cells [15]. 

Figure 5.26 shows a schematic diagram of the power system for a mild hybrid car. In addition to the 12-volt battery that is standard on conventional autos, the hybrid car carries a 42-volt battery pack. The electrical energy from this battery pack is not employed to move the car directly an electrical engine capable of doing that, as in the full hybrids, requires from 150 to 300 volts. In the mild hybrid cars the added electrical source is employed to run various auxiliary devices that would oth-... 

For starting up the fuel cell system, electric heaters inside the cooling media are chosen. The required power during start-up is provided either from an external supply or from the battery pack in the hybrid variant, making the aircraft more autonomous. A total energy of approximately 6 kWh is theoretically required to heat up the system mass from 0 to 130 °C. The installed heating power is limited because the... 

The material cost of a battery pack is strictly dependent on the energy level, electrical load, and battery capacity requirements. Suitable materials are required for fabrication and protection for the active cathode, anode, electrolyte, separator, cell, and pack container or housing. The latest material cost estimates for a typical high-energy rechargeable battery pack with 100 Ah capacity are summarized in Table 4.9 [7]. 

The performance characteristics of the thin prismatic batteries are similar to those of the other sealed units. Their advantage becomes more apparent in the fabrication of battery packs as the minimum of void space required in the pack enhances the energy density. 

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