The new battery is the correct model and voltage as shown at Parts-People here. That is a 6 cell battery. The 4 cell was 14.8V (or 14.5 in your case possibly). You can use it and it will work properly, don't have any worries about it. And the model number of your system is an Inspiron 14R 5421.
Hello, If I bought a new battery to a Dell inspiron 15 33308 notebook, origianlly it had MR90Y, 5421 Model: BC04  14.5V === 26000mAh/38Wh, and the new one is: MR90Y, 5421, 11.1V ===4400mAh/49Wh, the voltage is different and they look the same (I just have photos of them),  can I replace the old one with the newer ??  
battery Replacment for inspiron 15 33308