What is it

While trying to photograph a crystal build up in my Rolls S605 batteries i noticed that some had what looked like a solid grey lead bar inside , it was present in about 5 cells laying diagonally across the plates , in others it was only just visitable as it was running at a 90 degree angle to the plates and touched up inside against the inner compartment wall  . Carefully poked it with the rubber pipe on my hydrometer but it didnt move , just odd that it appears diagonally in a cell in one battery but not always the corresponding cells on another . I haven't ever noticed before however thats not to say they were not there . I thought possibly a electrical connection placed in the cells thats didnt necessary need to be placed in a specific position so its visible on some but not others although manufacturing things on mass normally means uniformity . Could only photograph the diagonally bars as the others were tucked away to far for the camera to get a shot of them .