PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
View Single Post
Old 26th Jan 2013, 08:30
  #148 (permalink)  
saptzae
 
Join Date: Aug 2011
Location: hong kong
Age: 63
Posts: 93
Likes: 0
Received 0 Likes on 0 Posts
Battery and cell monitoring

Temperature would be used to limit fast charge current. Management system will lower max charge current at higher temperature.

Cell voltage change precedes temperature change. Once the temperature rises substantially, it will be too late to manage.

When a cell arcs internally or shorts, the voltage will fluctuate a lot and reduce to near zero.

When a cell electrically opens, voltage across it will revert and the battery shows a high inner resistance.

Important is to keep individual cell voltages in the allowed range at _all_ times, or disconnect the battery.

Thus, per cell temperature monitoring would not be a big benefit to battery management.

Important is that charge current be reduced quickly when any cell's voltage approaches it's limit, and that it never increases the design limit.

When _any_ cell over/under/reverse voltage is detected, the entire battery must be taken off-line (disconnected) within a very short time to prevent secondary damage to it.
saptzae is offline