Battery Pack Bus Bar Branch Layout for Balanced Voltage Sensing
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Solution Overview
Problem
Existing battery packs face issues with voltage and temperature imbalances due to uneven voltage distribution across bus bars, leading to potential inefficiencies and instability.
Innovation Solution
The battery pack design incorporates diverged branches in the bus bars, specifically cut at the 2/3 point from one end, to minimize voltage differences and maintain balanced voltage and temperature distribution across the cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If bus bars are used to connect battery cells in series/parallel configurations, then electrical connectivity and power output are improved, but voltage distribution becomes uneven across the bus bar structure leading to measurement inaccuracies
Solution Approach 1:
The bus bar is segmented into multiple measurement points along its length, with voltage sensors positioned at different locations to capture the voltage distribution profile. This segmentation allows the system to measure and identify voltage drops at different segments of the bus bar, enabling accurate determination of the average voltage despite the presence of voltage gradients across the extended bus bar structure.
Solution Approach 2:
A control device acts as an intermediary between the voltage sensors and the battery management system. The control device receives voltage signals from multiple sensors positioned at different locations on the bus bar, processes these signals to calculate the average voltage, and provides this corrected voltage information to the battery management system, thereby compensating for the voltage distribution non-uniformity.
2Device complexity
If voltage sensors are positioned at single locations on bus bars, then device complexity is reduced, but voltage sensing accuracy deteriorates due to voltage drops across the bus bar
Solution Approach 1:
Instead of using a single voltage sensor, the system employs multiple voltage sensors positioned at different locations along the bus bar (e.g., at the first end, middle, and second end). This segmentation of the measurement function allows the system to capture the voltage distribution across the bus bar, enabling accurate calculation of the average voltage while maintaining manageable device complexity through a systematic sensor arrangement.
3Quantity of substance
If battery cells are connected in series/parallel to form high-capacity packs, then energy storage capacity is improved, but temperature distribution becomes non-uniform across the battery pack
Solution Approach 1:
Temperature sensors are positioned at different locations within the battery pack to capture the local temperature conditions of different cell groups. The control device processes these distributed temperature measurements to determine the average temperature of the battery pack, enabling thermal management decisions that account for the non-uniform temperature distribution while maintaining the high energy storage capacity achieved through series/parallel cell connections.
Data Source
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AI summary
A battery pack including a plurality of battery cells; a first case accommodating the plurality of battery cells; a protection circuit module coupled to one side of the plurality of battery cells and electrically connecting the plurality of battery cells; a bus bar electrically connected to the protection circuit module and extending in one direction along the plurality of battery cells; and a second case coupled to the first case and accommodating the plurality of battery cells, the protection circuit module, and the bus bar, wherein the bus bar includes a diverged branch formed by cutting a region of the bus bar in the one direction.