With that big a crack, the cell is probably shattered. If creative, you can short the bypass diode for that section and use it at a lower voltage and pair it with a small boost converter. I have a pair of 12V 75W Photowatt panels that went bad. I used the good 6V section of each panel and put two in series. Then they went bad. So much for 25 year warranties. Even BP isn't around anymore. I figure to sell the pair of panels for $15 to someone who needs a frame and low iron glass. I assume these panels are just a gooey mess to pull apart.