Implementation of an Automatic Checking Machine for Battery Welding Condition

The common automobile battery is composed of series connection of six units of battery chargers, with the tab welded between each battery charger for a purpose of connection. Thus the satisfactory welding point will be closely related to the lifetime of the battery. If the welding point is not solid enough, it will produce high resistance and heat in welding point upon numerous current discharge and charge, thus leading to a breakage of the welding point and causing damage to battery. This essay aims to implement a checking machine for battery welding condition. This machine based on a microprocessor as the core of control by combining a direct current power supply to measure the internal resistance of welding point of the battery so that the condition of the welding point can be judged. Upon the signal of inner resistance goes through an amplifier and then a buffer circuit, this analog signal will be converted into a digital signal and then be conveyed to the microprocessor. Finally, the configuration is displayed by an LED, which also reveals the results of measurement upon the comparison of the signal and a setup value. In the meanwhile the relay contact can be used to notify the PLC of the auto wire to show the condition of the battery, while RS485 or RS232 can be used to link with computer to record the welding condition of the battery.