Wikipedia
The name of Karna's wife is not mentioned in Mahabharat. But it can be safely concluded that he had only one wife (unknown name). The name Vrishali makes sense as the name of Karna's wife because original name of Karna was Vrisha or Brisha as per original epic, hence his wife would be called as Vrishali also called as Brishali or Vrushali.
Very little is known about Vrushali, except that she was a pious woman hailing from the charioteer caste and chosen by Karna's adoptive father Adhiratha, also of the same caste. According to the Udyoga Parva Bhagavatayana, in shloka #1011, where Karna declines Lord Krishna's offer to defect from Duryodhana's camp, the warrior states :
Naama vai vasusheneti kaarayaamaasa maadhava I
Bhaaryaashchoda mama praapte yauvane tatparichhaat II