Trickle current isn't the same as charging current!
Trickle is the maximum current you should allow AFTER the charging is completed, in other words how much it is safe to pass through the cell when it is fully charged without causing 'over charge' problems.
The minimum component count would be one resistor and one Zener diode, but it wouldn't be the most efficient was of doing it. You place a Zener diode (say 8.2V across the cell) then use the 600 Ohm resistor suggested by Easyrider83. If the cell voltage is below the Zener voltage, all the current flows into the cell, as it approaches Zener voltage, the current starts to divert through the diode instead. The problem with this simple method is it draws current from the source all the time, regardless of the cell condition so it is wasteful of power althoug this may not be a problem in your situation. The other drawback is getting exactly the right Zener voltage to ensure the cell reaches full voltage before the current diverts. A better design would have a sharp and adjustable cut-off voltage, you may have to rely on the particular Zener voltage being close enough or building it up from a lower Zener voltage Zener diode and one or more normal diodes in series.
Brian.