I'm trying to export an image using a FeatureCollection as region. My code is as follow:

params = {
    'description': 'ndviChange_to_gtiff',
    'scale': 30,
    'region': AOI
  }
ee.batch.Export.image.toDrive(ndviChange, **params)

the AOI is a FeatureCollection defined earlier in my code:

AOI = ee.FeatureCollection("users/..../AOI")

I'm getting this error:

TypeError: Object of type FeatureCollection is not JSON serializable

Note that I'm running the code in QGIS GEE plugin.