How to config webpack-4 to generate multiple chunks for code splitting?

Question

I already set multiple different webpackChunkName in react-loadable, I set 10 different chunks, but only got 5 chunks. Some chunks were combined, I want to get 10 different chunks. how to config it? THX

export const AsyncAAA = Loadable({
  loader: () => import(
    /* webpackPrefetch: true, webpackChunkName: "AAA" */ 
     "containers/AAA"
  )
});

export const AsyncBBB = Loadable({
  loader: () => import(
    /* webpackPrefetch: true, webpackChunkName: "BBB" */ 
     "containers/BBB"
  )
});

export const AsyncCCC = Loadable({
  loader: () => import(
    /* webpackPrefetch: true, webpackChunkName: "CCC" */ 
     "containers/CCC"
  )
});