Battery Module Pre-Charging Sequence for Stable Parallel Connection
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Solution Overview
Problem
Existing battery systems face instability due to significant variations in current consumption by controllers when pre-charging relays are switched on simultaneously, leading to voltage fluctuations and potential system instability.
Innovation Solution
The battery system performs a pre-charging process sequentially on each battery module, staggering the activation of pre-charging relays to reduce overall current consumption and maintain stability by controlling the connection of battery modules to output terminals through a controller that manages the switching of main and pre-charging relays based on voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pre-charging relays of multiple battery modules are switched on simultaneously, then the pre-charging process is completed faster, but current consumption varies greatly causing voltage fluctuations and system instability
Solution Approach 1:
The patent divides the simultaneous pre-charging operation into segmented sequential operations. Instead of switching on all pre-charging relays at once, the controller activates them one by one in a predetermined sequence. This segmentation of the pre-charging process prevents sudden large current consumption while still achieving pre-charging functionality, thereby resolving the contradiction between speed and stability.
2Loss of time
If pre-charging relays are switched on simultaneously, then the pre-charging process is completed faster, but current consumption variations apply load to power supply causing voltage variations
Solution Approach 1:
The controller performs preliminary sequencing of pre-charging relay activation before actual pre-charging begins. By pre-planning and executing relay switching in a predetermined sequence rather than simultaneously, the system prepares for controlled current distribution in advance. This preliminary action prevents sudden current spikes and maintains stable power supply voltage throughout the pre-charging process.
3Reliability
If sequential pre-charging is performed on battery modules, then current consumption variations are reduced and stability is maintained, but the pre-charging process takes longer
Solution Approach 1:
The patent implements periodic action by activating pre-charging relays at regular intervals in a sequential manner. Rather than simultaneous activation, each pre-charging relay is switched on after a predetermined time interval from the previous one. This periodic sequencing maintains system stability by preventing current surges while completing the pre-charging process efficiently through systematic progression.
Data Source
AI summary
A battery system includes: a pair of output terminals connected to a load; battery modules connected to the output terminals and disposed in parallel to each other; and a controller. Each of the battery modules includes: a battery unit including cells connected in series to each other; a main relay provided on a first side end portion of the battery unit; a unit relay provided on a second side end portion of the battery unit; and a pre-charging unit provided in parallel to the main relay. The controller includes a pre-charging process executor configured or programmed to, when the battery modules are to be connected to the load, exercise control so as to connect the battery modules to the pair of output terminals after having executed a pre-charging process on the battery modules on a one-by-one basis.