Risk of battery fire after logic board spark

I've had this MacBook pro since 2013 and in 2015 juice was spilled on it and it no longer worked. Now, 5 years later I decided to take a look at the laptop and see if I could clean it up and fix it. I took it apart, cleaned it with alcohol, and reassembled it. I powered it on and it worked for a couple of minutes, the batteries charged to 12%, but then it shut down. I tried to power it back on but the backlight kept coming on and off and no boot. I went to disconnect the battery from the logic board but when my screwdriver touched the screw on the connector it sparked. Fearing that the batteries may catch fire I put it outside for now. Does anyone know the likelyhood that the batteries may catch fire. Keeping in mind the batteries have been sitting for about 5 years.