Vehicle Battery Pack Selection Using Voltage Reversal Timing
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Solution Overview
Problem
In vehicles with parallel-connected battery packs, voltage fluctuations lead to incomplete utilization of battery capacity due to missed timing in controlling contactors, restricting cruising distance.
Innovation Solution
A vehicle control device that acquires and compares voltage values of battery packs, selecting active and standby packs based on voltage differences to ensure simultaneous usage and optimal power distribution, allowing all packs to be utilized during travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery pack with the highest voltage is used first and contactors are closed when voltage difference becomes less than a prescribed value, then the voltage fluctuation between battery packs is managed, but the contactors cannot be controlled during discharge period when voltage magnitude relationship reverses, causing some battery packs to remain unused and restricting cruising distance
Solution Approach 1:
The patent implements dynamic switching of battery pack selection based on real-time voltage comparisons. The control unit continuously monitors voltage values and dynamically changes which battery pack is selected as the drive battery pack. When voltage difference exceeds the threshold during discharge, the system dynamically switches to use the standby battery pack, ensuring continuous utilization of all battery packs and extending cruising distance.
Solution Approach 2:
The control unit continuously acquires voltage values from all battery packs and uses this feedback information to make real-time decisions about contactor control and battery pack selection. The system compares current voltage values with previously stored values and adjusts contactor states accordingly, ensuring that voltage fluctuations are managed while maximizing the use of all battery packs throughout the discharge period.
2Stability of the object's composition
If contactor control is restricted to maintain voltage difference within prescribed value, then voltage stability is ensured, but the timing to control closing of contactor may be missed during discharge, leaving battery packs unused
Solution Approach 1:
The control unit stores the voltage value of the battery pack that was previously selected as the drive battery pack. By having this preliminary stored value ready for comparison, the system can quickly determine when voltage difference exceeds the threshold and immediately switch to the standby battery pack, preventing missed control timing and ensuring continuous utilization of all battery packs.
Solution Approach 2:
The system continuously monitors voltage values and compares them with stored reference values, providing real-time feedback for contactor control decisions. This feedback mechanism ensures that voltage stability is maintained while promptly responding to voltage changes that would trigger battery pack switching, thereby maximizing productivity and battery pack utilization.
Data Source
AI summary
A vehicle control device includes a voltage information acquisition unit that acquires respective voltage values of a plurality of battery packs, a voltage value comparison unit that compares, when a state of an accelerator pedal of a vehicle is switched from an ON state to an OFF state, a voltage value of an active battery pack that is being used to drive the vehicle with a voltage value of a standby battery pack having a highest voltage value among the battery packs that are not being used to drive the vehicle on a basis of the voltage values acquired by the voltage information acquisition unit, and a selection unit that selects a drive battery pack allowed to perform discharge to drive the vehicle from among the plurality of battery packs on a basis of the comparison by the voltage value comparison unit.