I finally found the solution.
When you call renderPartial you must set the 3rd parameter = FALSE and the 4th parameter = TRUE.
$this->renderPartial('ajax_view',array(
'model'=>$model,
'dataProvider'=>$dataProvider,
),false,TRUE);
From the official documentation:
$return boolean whether the rendering result should be returned instead of being displayed to end users $processOutput boolean whether the rendering result should be postprocessed using processOutput.
And the MOST IMPORTANT TWEAK: Inside the view rendered with renderPartial you must add:
Yii::app()->clientscript->scriptMap['jquery.js'] = false;
The page is reloaded simply 'cause jquery was loaded multiple times.