Passive Protection - Keysight A Series User Manual

Safety Considerations
Battery Protective Functions
Secondary Overdischarge Current: This prevents the battery from being
discharged if the current out of the battery reaches or exceeds 6A for a time
period of 20 milliseconds or more. This protection can be reset by removing the
load.
Short Circuit Protection: This prevents the battery from being charged or
discharged and protects against damage or lost data if the current ins or out of
the battery reaches or exceeds 33.3A for a time period of 274.5 microseconds
or more. This protection can be reset by removing the load.
Overtemperature Charging: The system microcontroller prevents the battery
from being charged if the cell temperature exceeds 48C. Once the
overtemperature charging protection is tripped, the cell temperature has to
drop to or below 43C to reset the protection and permit charging.
Overtemperature Discharging: The system microcontroller prevents the
battery from being discharged if the cell temperature exceeds 67C. Once the
overtemperature discharging protection is tripped, the battery is automatically
shut off which results in turning off the instrument as well.

Passive Protection

Reverse Charging: A reverse protection diode prevents against damage or lost
data due to a reverse charge polarity applied to the battery terminals.
Primary Overtemperature: The maximum operating temperature of this fuse is
85C. An overtemperature cutout permanently opens at 85C with no recovery.
Secondary Overtemperature: A second PTC polyfuse built into each Li-ion cell
will open up and limit current flow as a function of very high temperatures.
Tertiary Overtemperature: A current interrupt device (CID) within each Li-ion
cell will permanently open up when the temperature reaches 95C. As each cell
fuse is permanently interrupted, overall battery performance will become
severely degraded, up to and including disabling the battery.
Keysight N9927-90020 User's Guide 813