Distributions　of　current　density　and　potential　on　the　automotive　negative　plate　during　its　formation　and　discharge　processes　have　been　studied　by　an　in　situ　electrochemical　scan　technique.　It　is　found　that　the　current　and　potential　distributions　are　uneven　at　the　beginning　of　the　formation.　However,　these　distributions　are　much　more　uniform　than　those　of　the　positive　plate　and　the　resistance　is　much　smaller　because　of　the　lead　skeleton　formed　on　the　negative　plate.　At　the　end　of　the　formation　the　distributions　are　relatively　uniform,　and　the　current　density　in　the　upper　part　of　the　plate　is　a　little　higher　than　that　in　the　lower　part.　The　resistance　and　the　polarization　increase　obviously　at　the　bottom　and　on　the　top　of　the　negative　plate.　During　its　discharge,　the　polarization　is　also　high　and　the　utilization　of　the　negative　active　mass　becomes　low　in　these　regions.　Therefore,　the　formation　of　the　negative　plate　greatly　affects　the　current　and　potential　distributions　and　the　battery　performance　in　its　discharge.　©　2006　The　Electrochemical　Society.　All　rights　reserved.