vue3 elementui的el-date-picker的v-model赋值日期字符串数组无反应,怎么回事?

      <el-date-picker
          v-model="date_picker_value"
          type="daterange"
          start-placeholder="开始日期"
          end-placeholder="结束日期"
          value-format="YYYY-MM-DD"
          @change="dateChange"
          unlink-panels
          range-separator="至"
      />

let date_picker_value = reactive(['',''])

  date_picker_value[0] = '2021-11-24'
  date_picker_value[1] = '2022-2-22'