pythonマルチスレッド方式は複数のbatコードを実行します。

import threading
from win32api import *

class MyThread(threading.Thread):
  def __init__(self, bat_path, **kwargs):
    threading.Thread.__init__(self, **kwargs)
    self.bat_path = bat_path
    
  def run(self):
    ShellExecute(0, None, self.bat_path, None, "c:", True)
  
for i in range(1,4):
  t = MyThread("c: est" + str(i) + ".bat")
  t.start()