This is a customizable storage box for 9V batteries. The uploaded .stl file is for a 4 x 3 which stores 12 batteries.

The tolerance is a buffer around each battery in both X and Y because there is a slight variation in the size of batteries. I measured several ones and chose the largest as the default.

The uploaded .stil was created with the following parameters:
battery_width = 17;
battery_length = 26;
battery_height = 48.75;
number_of_batteries_wide = 4;
number_of_batteries_long = 3;
inner_wall_thickness = 1.32; // 3 (lines) 0.44 (line width)
outer_wall_thickness = 2.64; // 6 (lines) 0.44 (line width)
bottom_thickness = 2.64; // 12 (lines) * 0.22 (line height)
height_percentage = 50;

// Distance around battery. Increase if too tight. Decrease if too loose.
tolerance = 0.5;