Current Interruption Circuit for Electrical Storage Overcharge Protection

The patent divides the control system into two independent parts: a controller that handles high-level control functions and a dedicated current interruption circuit that handles safety-critical overcharge protection. This segmentation ensures that program changes in the controller do not affect the reliability of the overcharge protection function, as it is implemented in dedicated hardware circuitry rather than software.

The current interruption circuit acts as an intermediary safety mechanism between the controller and the electrical storage device. It independently monitors charging current and directly interrupts power supply when overcharge conditions are detected, bypassing the controller's program-based control. This intermediary layer provides fail-safe protection regardless of controller program status.

The control system is segmented into normal control functions (handled by the controller) and emergency safety functions (handled by the current interruption circuit). The current interruption circuit includes dedicated components such as a comparison circuit for monitoring voltage, a latch circuit for maintaining the interrupt state, and a current interruption switch for physically disconnecting power. This segmentation enables independent operation of the safety function without adding excessive complexity to the overall system.

The current interruption circuit is pre-configured with threshold values for overcharge detection and is continuously monitoring the charging state. When overcharge conditions are detected, the circuit automatically triggers the latch mechanism to maintain the relay in the off state, preventing any possibility of energization resumption even if the controller fails or is reset. This preliminary safety action ensures reliability without requiring complex real-time controller intervention.

The patent replaces frequent mechanical relay switching with a more sophisticated control approach. The current interruption circuit uses a comparison circuit to monitor voltage thresholds and a latch circuit to maintain the relay state, reducing the need for frequent mechanical switching. The relay only switches when necessary (normal on/off states), while the latch circuit provides continuous monitoring and automatic maintenance of the safe state, thereby reducing mechanical wear while maintaining precise control.

The latch circuit provides self-service functionality by automatically maintaining the relay in the off state when overcharge conditions are detected, without requiring continuous controller intervention or frequent switching. Once the latch is triggered, it maintains the protective state until manual reset or power cycle, eliminating the need for repeated relay actuation and thereby reducing abrasion degradation while maintaining precise control over the charging process.