A cell cannot contain 20 different names unless the cell contains another cell, or a character array (which means all the names are the same length).
Your "Names" variable can be a 1x20 cell array - that is, an array of cells . Each cell (of the 20 cells in the array) may contain one string, or one of anything else, such as another cell, a double matrix, a structure, a table, etc. Please read the FAQ for an explanation of what cells are and how they work. http://matlab.wikia.com/wiki/FAQ#What_is_a_cell_array.3F
Not sure why you're asking about cells at all. If you have 20 named variables like VarName1 VarName2, and so on, you can rename them and retain their data/values like this:
newVar1 = VarName1; % Copy to new variable with new and different name.
clear('VarName1'); % Delete old variable with old name.
newVar2 = VarName2;
clear('VarName2');
newVar3 = VarName3;
clear('VarName3');
and so on down to 20.
If you want those 20 separately named variables in a new cell array , with one variable in each cell, you can do this:
ca{1} = VarName1; % Copy to new variable with new and different name.
clear('VarName1'); % Delete old variable with old name.
ca{2} = VarName2;
clear('VarName2');
ca{3} = VarName3;
clear('VarName3');
