Does it really help to store batteries in the refrigerator?

Yes, but only if they can be kept dry as well. The higher the temperature, the more the free flow of ions or self-discharge from the battery. Storing primary batteries (D's, C's, AA's, AAA's, 9 volt, etc.) in a cooler environment slows down this rate of discharge that all batteries experience even when not in use, hence a longer shelf life. However, if this is done, it is important that the batteries be kept as dry as possible by keeping them in an airtight container in the driest part of the refrigerator, the door side for example. Long time exposure to moisture inside the refrigerator can cause internal corrosion to the battery. When removing batteries from the refrigerator, allow them to warm up to room temperature before using them in your device.