To reduce an indirect communication cost, and to easily and effectively monitor a battery by including an up-link communication stream for converting a processor signal into a rating logical level of respective plural modules and a down-link communication stream for convering a module signal into a rating logical level of the respective plural modules.

Respective modules 5 include a VLTI receiver 7, a transmitter 6 and a remote control measurement and safety microcontroller 501 besides a cell 51. The receiver 7 receives information and a command from HC and C. The microcontroller 501 monitors an up-link via the receiver 7 on information transmitted from the HC and C to the receiver of the modules 5. The transmitter 6 forms a down-link data channel, and data response sent out on this channel advances to the lower order module from the module for sending the data response before being finally received by the HC and C.