Construction And Characteristics Of Nickel Hydrogen Batteries - Yamaha JW-II Service Manual

Battery
+ positive electrode
terminal (built into gas
discharge valve)
Sealing plate
Gasket
Positive
electrode
collector tab
Canister
- negative
electrode
terminal
Spring
Restraining plate
Valve post
Positive electrode insulating washer
Separator
Negative
electrode
plate
Positive electrode plate
Construction and Characteristics of
Nickel Hydrogen Batteries
Nickel hydrogen batteries are handled very dif-
ferently from ordinary automotive batteries
(lead batteries).
The construction of the nickel hydrogen
battery
Nickel hydrogen batteries are constructed with
nickel oxide on the positive electrode, a hydro-
gen-absorbing alloy on the negative electrode,
a separator, alkali electrolytic fluid, a metal can-
ister, and a sealing plate with a gas discharge
valve, as well as other components.
Charging
When a nickel hydrogen battery becomes hot,
it is more difficult to charge, and it becomes im-
possible to charge it fully.
Repeatedly charging the nickel hydrogen bat-
tery at high and low temperatures shortens the
service life of the battery.
A temperature sensor built into the battery con-
stantly monitors the battery temperature.
NOTE:
•
Charging a warm battery in a warm location may
take longer than the normal charging time. The
customer should be advised to charge the bat-
tery at an ambient temperature of 30°C or less.
•
The battery can be charged as long as the
surface temperature is between 0°C and 40°C.
Outside this temperature range, the charger
goes into temperature standby mode. (The
charging LED flashes.) If the battery is too
warm, or has been stored in a cold place, it
may not be possible to charge it right away.
•
If the temperature varies from the range noted
above while the battery is being charged, the
charger goes into the temperature standby
mode, even though charging is still in progress.
Full charging
Excessive charging causes nickel hydrogen
batteries to deteriorate, resulting in a de-
creased battery capacity.
The XA4 battery control unit is designed to pre-
vent battery deterioration caused by excessive
charging. To do this, it judges whether the bat-
tery is fully charged, and if so, it sends a signal
to the charger while the battery is still con-
nected to the charger, indicating that no further
charging is needed.
When the charger receives this signal, it termi-
nates output of the charging current, but the
display continues to indicate that charging is in
progress for about 10 minutes.
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