<el-table-column
          :show-overflow-tooltip="true"
        v-for="(column, index) in columns"
        :key="index"
        :type="column.type"
        :prop="column.prop"
        :label="column.label"
        :width="column.width"
        :fixed="column.fixed"
        :sortable="column.sortable"
      >
      </el-table-column>

vue里面廷加省略号

:show-overflow-tooltip="true"