To Generate release apk in cordova firstly create release-signing.properties in cordova/platform/android location of your project. (this is for latest Cordova apps)
with below content :
storeFile=yourapp.keystore storeType=jks keyAlias=alieaskey
If your app is created bit older cordova version and above not working, then create ant.properties in cordova/platform/android location of your project.
Content of ant.properties should be something like:
Command to build android release apk :
cordova build android –release