Exposure value is just a product of the shutter speed and aperture of your camera and lens combo that captures a fixed measure of light. This is expressed as a number. But the real deal is that by changing the shutter speed and aperture combination you can capture the same quantity of light. That in effect means different combinations of shutter speed and aperture can have the same EV. This happens because shutter speed and aperture has an inverse relationship. When you increase one you have to decrease the other so that you can maintain the same exposure.
Knowledge of this fundamental is also important because you can then alter the depth of field and or incorporate motion blur in your images without fundamentally changing the exposure.