Are the chemical reactions that take place when a battery is connected endothermic or exothermic? be specific as you explain your answer.

The question is too broad. Depends of the battery and depends where do you connect it to.

define first a battery reaction and where it is connected to define if the reaction is endo or exothermic.

If a battery reaction is exothermic when it is connected to a circuit may be endothermic when it is charged (reverse reaction). 

some batteries at low temperature tends to work less, that suggest, they may need absorb some energy from the surroundings. 

Ithink is a because if say increased in electronegativity