Battery Pack Auxiliary Charging Device for Cell Abnormality Management
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Solution Overview
Problem
In battery packs with multiple secondary battery cells connected in parallel or series, abnormalities in one cell can lead to reduced power supply to devices, increased burden on normal cells, and inefficient charging/discharging, as existing solutions do not effectively manage load balancing and voltage compensation.
Innovation Solution
A battery pack design that includes a battery assembly with parallel or series-connected secondary battery cell modules and an auxiliary charging/discharging device, which connects in parallel with normal cells during normal operation and in series with abnormal cells, allowing for efficient charging/discharging and balancing of cell voltages without stopping the battery pack's use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection circuit stops the charge/discharge operation of the entire battery pack when an abnormality occurs in one secondary battery cell, then the protective function is realized, but the operations of all power consumption devices are stopped and all secondary battery cells are out of use
Solution Approach 1:
The battery pack is divided into multiple independent secondary battery cell groups, where each group can be independently managed. When an abnormality occurs in one cell, only that specific cell or group is disconnected, while other groups continue to operate, thus maintaining overall system productivity while ensuring safety through localized protection.
2Reliability
If the secondary battery cell at which the abnormality has arisen is disconnected from the battery assembly, then the protective function is realized, but all of the secondary battery cells connected in series are out of use
Solution Approach 1:
The battery assembly is segmented into multiple parallel-connected secondary battery cell groups. When an abnormality is detected in one cell, the system disconnects only that specific cell while maintaining connections for other cells and groups, allowing the battery pack to continue operating at reduced but non-zero capacity.
Solution Approach 2:
Multiple secondary battery cell groups are merged in parallel configuration, where each group can independently contribute to the overall power output. This parallel merging ensures that if one group fails, the others can compensate and maintain system operation.
3Reliability
If the power supplied to the power consumption device is reduced when one secondary battery cell has an abnormality in parallel connection, then the abnormality is isolated, but the burden of the normal secondary battery cell is increased
Solution Approach 1:
The system performs partial action by disconnecting only the abnormal cell while keeping other cells in the parallel configuration active. This approach isolates the abnormality without requiring complete system shutdown, and the remaining cells share the reduced load rather than being overloaded, as the total power demand is adjusted to match the available capacity.
4Reliability
If the means for compensating for voltage in proportion to the disconnected battery is provided, then voltage balance can be maintained, but the device complexity is increased and efficient charging/discharging is not achieved without abnormality
Solution Approach 1:
The charging/discharging system automatically detects voltage imbalances among parallel-connected secondary battery cell groups and self-regulates the charging current distribution without requiring external intervention or complex control circuits. Each group receives appropriate current based on its state of charge, maintaining voltage balance naturally through the charging process.
Data Source
AI summary
Provided is a method for charging/discharging a battery pack having an auxiliary charging/discharging device and a battery assembly in which a plurality of secondary battery cell parallel modules, each of which includes a plurality of fasecondary battery cells connected in parallel, are connected in series, the method including, when there is no abnormality in the secondary battery cells during charging/discharging, connecting the auxiliary charging/discharging device in parallel to any of the secondary battery cell parallel modules, and when there is an abnormality in any of the secondary battery cells during charging/discharging, releasing connection to the secondary battery cell at which the abnormality has arisen in the secondary battery cell parallel module including the secondary battery cell at which the abnormality has arisen, and connecting the auxiliary charging/discharging device in parallel to the secondary battery cell parallel module including the secondary battery cell at which the abnormality has arisen.