Angular JS Form Validation

It sounds like you want empty rows to be valid, but empty input fields in a non-empty row to be invalid.

To achieve this, you can add conditional requirements to each field using ng-required, so that it is only required if there is at least some text elsewhere in the row.

From your plunkr, you can replace required with ng-required on each input:

<li ng-repeat="cell in cells">
    <input type="text" name="dest" ng-model="cell.dest" placeholder="Destination Link" ng-required="cell.src || cell.name"/>
    <input type="text" name="src" ng-model="cell.src" placeholder="Image Link" ng-required="cell.dest || cell.name"/>
    <input type="text" name="cellName" ng-model="cell.name" placeholder="Name" ng-required="cell.src || cell.dest"/>
</li>

To improve scalability, you could also define a method on the cell objects or the controller to evaluate whether a cell object is blank:

function cellCtrl($scope) {
    ...
    $scope.isBlankCell = function(cell) {
        ...
    }
}

and call that method from the template:

<li ng-repeat="cell in cells">
    <input type="text" name="dest" ng-model="cell.dest" placeholder="Destination Link" ng-required="isBlankCell(cell)"/>
    <input type="text" name="src" ng-model="cell.src" placeholder="Image Link" ng-required="isBlankCell(cell)"/>
    <input type="text" name="cellName" ng-model="cell.name" placeholder="Name" ng-required="isBlankCell(cell)"/>
</li>