问为什么批量标准化会降低我的模型训练精度？

EN

model = Sequential()
    model.add(Conv2D(32, (3, 3), input_shape=input_shape))
    model.add(Activation('relu'))
    model.add(BatchNormalization())
    model.add(MaxPooling2D(pool_size=(2, 2)))
    
    #first hidden layer 
    model.add(Conv2D(32, (3, 3)))
    model.add(Activation('relu'))
    model.add(BatchNormalization())
    model.add(MaxPooling2D(pool_size=(2, 2)))
    
    #output layer
    model.add(Flatten())
    model.add(Dense(64))
    model.add(Activation('relu'))
    model.add(Dropout(0.5))
    model.add(Dense(1))
    model.add(Activation('sigmoid'))
    model.summary()
    
    model_checkpoint = ModelCheckpoint( "model.hdf5", verbose=1, save_best_only=True)
    model.compile(loss='binary_crossentropy',
                  optimizer= 'adam',
                  metrics=['accuracy'])