Battery Pack Switch Timing to Prevent MOSFET Short Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Battery packs face safety risks due to direct short circuits and electric arcs caused by simultaneous activation of first and second switches, which are typically implemented with multiple MOS transistors in parallel, leading to permanent failures.
Innovation Solution
Implementing a battery system with parallel-connected controllable switching transistors in the first and second switches, ensuring they are turned on at different moments to prevent simultaneous activation, using asynchronous drive signals to manage current flow and automatically turn off transistors under excessive load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple MOS transistors are connected in parallel to increase current bearing capacity, then the current handling capability is improved, but the risk of simultaneous switch activation and direct short circuit increases
Solution Approach 1:
The patent applies preliminary action by detecting the activation state of the first switch before allowing the second switch to turn on. The control method proactively prevents simultaneous activation by checking whether the first switch is already on, and only permits the second switch to activate if the first switch is confirmed to be off. This preemptive control mechanism eliminates the harmful simultaneous activation state while maintaining the parallel MOS transistor configuration for high current capacity.
2Adaptability or versatility
If the first switch and second switch are both turned on to handle fault conditions, then the system's fault tolerance is improved, but direct short circuit and permanent failure occur
Solution Approach 1:
The patent implements feedback control by continuously monitoring the activation state of the first switch and using this information to control the second switch. The control method reads the first switch's state and adjusts the second switch's activation accordingly - preventing the second switch from turning on when the first switch is already active. This feedback mechanism maintains system adaptability for fault handling while preventing the harmful short circuit condition.
3Device complexity
If a single MOS transistor is used for the first and second switches, then the device complexity is reduced, but the current bearing capacity is insufficient
Solution Approach 1:
The patent applies segmentation by dividing each switch (first switch and second switch) into multiple parallel MOS transistors. Instead of using a single MOS transistor that would be insufficient for high current applications, the system segments the current path across multiple parallel devices. This segmentation approach increases the current bearing capacity while maintaining relatively simple control logic through the state detection mechanism.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This application discloses a battery system, a drive system, and an energy storage container. The battery system includes a plurality of battery packs that are connected in series. Each battery pack corresponds to one first switch that is connected in series to the battery pack. Each battery pack corresponds to one second switch that is connected in parallel to the battery pack. Each battery pack is connected in series to the corresponding first switch and then connected in parallel to the second switch. The first switch includes a plurality of controllable switching transistors that are connected in parallel. The second switch includes a plurality of controllable switching transistors that are connected in parallel. The plurality of controllable switching transistors included in the first switch correspond to at least two different turn-on moments. The plurality of controllable switching transistors included in the second switch correspond to at least two different turn-on moments. After the first switch is turned on, a current is large. A batch of controllable switching transistors that are first turned on in the second switch are automatically turned off because of an excessively large current, and therefore the second switch is not successfully turned on. A positive electrode and a negative electrode of the battery pack are not short-circuited together. Therefore, the battery pack is not short-circuited for a long time. This ensures safety of the battery pack.