In vue.config.js add to pluginOptions: electronBuilder: { externals: ['serialport'] }

module.exports = {
  pluginOptions: {
    quasar: {
      treeShake: true
    },
    electronBuilder: {
      externals: ['serialport']
    }
  },
  transpileDependencies: [
    /[\\\/]node_modules[\\\/]quasar[\\\/]/
  ]
}

Enjoy!