Transcript Chapter 6 — Batteries

PowerPoint® Presentation
Photovoltaic Systems
Batteries
Battery Principles • Battery Types •
Battery Systems
Arizona Solar Power Society
www.meetup.com/arizona-solar-power-society/
Chapter 6 — Batteries
Batteries are collections
of cells that produce
electricity through
electrochemical
reactions. Cells can be
configured into batteries
of many different shapes
and sizes.
Chapter 6 — Batteries
Many components are
common to various
battery types.
Chapter 6 — Batteries
Higher temperatures and
slower discharge rates
result in increased
battery capacity.
Chapter 6 — Batteries
Electrochemical
reactions within a cell
produce a flow of
electrons from the
negative terminal to the
positive terminal.
Chapter 6 — Batteries
Slower discharge rates
remove more energy
from a battery than faster
discharge rates.
Chapter 6 — Batteries
The state of charge and
depth of discharge of a
battery always add up to
equal 100%.
Chapter 6 — Batteries
When arrays are used to
charge batteries,
seasonal insolation
variations affect depth of
discharge values.
Chapter 6 — Batteries
Batteries exhibit high
self-discharge rates at
higher temperatures.
Chapter 6 — Batteries
The charging reaction
within a cell is the
reverse of the discharge
reaction.
Chapter 6 — Batteries
Bulk, absorption, and float charging control battery
voltage with the charging current during a multiplestage charging cycle.
Chapter 6 — Batteries
The freezing point of
sulfuric acid electrolyte
changes at various states
of charge because of
changes in specific
gravity.
Chapter 6 — Batteries
Sulfation reduces the
capacity of a lead-acid
cell by locking away
active material as
crystals.
Chapter 6 — Batteries
Stratification results
when the specific gravity
of the electrolyte is
higher at the bottom of a
cell than at the top.
Chapter 6 — Batteries
Batteries are divided into
classes based on
discharge and cycle
characteristics.
Chapter 6 — Batteries
Catalytic recombination
caps recombine oxygen
and hydrogen into water,
which then drains back
into the battery.
Chapter 6 — Batteries
Captive-electrolyte
batteries are sealed and
contain electrolyte that is
immobilized.
Chapter 6 — Batteries
The characteristics of lead-acid batteries vary
between different designs.
Chapter 6 — Batteries
Two types of nickel-cadmium batteries have different
performance characteristics.
Chapter 6 — Batteries
System requirements
and characteristics of
battery types must be
considered when
choosing a battery.
Chapter 6 — Batteries
Connecting batteries in
series increases system
voltage.
Chapter 6 — Batteries
Connecting batteries in
parallel increases
system capacity.
Chapter 6 — Batteries
Series and parallel
connections can be
combined to produce a
desired system voltage
level and capacity.