Page 336 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

Batteries and Ultracapacitors for Electric Power Systems with Renewable Energy Sources 323

This chapter is organized in eight sections. The main types and characteristics of batteries and
ultracapacitors along with their models are discussed in Sections 13.2 and 13.3. Energy storage
management systems (ESMSs) are covered in Section 13.4. In Section 13.5, interface systems for
ESSs are presented. Utility-level storage systems are discussed in Section 13.6 and the last section
of the chapter before the final summary includes simulation examples.

13.2 BATTERY ENERGY STORAGE SYSTEM: TYPES,
CHARACTERISTICS, AND MODELING

13.2.1 Lead-Acid
The oldest rechargeable battery technology, which was invented some 150 years ago, is based on the
use of lead-acid. The modern version of the technology is able to deliver relatively large power for
relatively low cost, making such batteries strong candidates for applications in which a surge power
support with low depth of discharge (DOD) is required, including backup power supply like UPS,
emergency power, and power quality management.
A short life cycle and very low energy density are two main disadvantages [5]. Deep cycling and
high discharging rate have a serious impact on the life span of the battery. The latest developments,
including advanced materials, resulted in lead-acid batteries to have better performance and longer
life cycle and include low-maintenance versions, such as GEL cells and Absorbed Glass Mat col-
lectively known as valve-regulated lead-acid batteries [6].

13.2.2 Lithium-Ion
One of the most popular types of batteries commercially available is based on Li-ion, which
provides comparatively very good performance, with high power density and satisfactory energy
density. A long life cycle without memory effect, together with high columbic efficiency and low
self-discharge characteristics, makes this type of battery the preferred energy storage choice for
a wide variety of applications, spanning from customer electronic devices and mobile products,
all the way to the latest generation of plug-in HEV and systems for frequency regulation at the
utility level [7].
The electrode material greatly influences the battery specifications in terms of power and energy
density, voltage characteristics, lifetime, and safety. A typical cathode, that is the positive active
electrode, is made of a lithium metal oxide and common materials such as cobalt (LiCoO or LCO)
2
and manganese (LiMn O or LMO). Combined chemistries including nickel, cobalt, aluminum
4
2
(NCA); nickel, manganese, cobalt (NMC); and iron phosphate (LFP) are also employed for the
cathode. Graphite and lithium titanate (Li Ti O or LTO) are the typical choices for the anode, that
4
5
12
is the negative active electrode.
A comparison of the battery chemistries, clearly illustrating the advantage of different battery
types, is presented in Table 13.3.
13.2.3 Sodium Sulfur
Sodium sulfur (NaS) rechargeable batteries are mostly developed for large-scale applications,
as they operate at a high operating temperature of 300 °C–350 °C. Such batteries are made with
inexpensive materials, are known as high-power and energy storage devices with high columbic
efficiency up to 90%, good thermal behavior, and are made with long life cycle. The primary
applications are large-scale power and energy support, such as load leveling, renewable energy
integration, and UPS systems. The battery contains hazardous materials like sodium, which can
burn spontaneously in contact with air and moisture or sodium polysulfide that is highly cor-
rosive [8].