Battery Cell Equalization via Grouped Discharge
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Solution Overview
Problem
Existing battery equalization methods generate excessive heat due to simultaneous discharge of multiple battery cells, leading to potential overheating and reduced battery lifespan.
Innovation Solution
Divide battery cells into groups and selectively discharge cells within each group at different timings, reducing the number of cells discharged simultaneously and distributing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple battery cells are discharged simultaneously during equalization, then equalization efficiency is improved, but heat generation increases excessively
Solution Approach 1:
The patent divides battery cells into multiple groups (first group, second group, etc.) and performs equalization discharge on different groups at different timings. Instead of discharging all cells simultaneously, the controller sequentially selects groups for discharge based on their charge states, thereby segmenting the overall equalization process into multiple smaller discharge events that occur at different times, reducing peak heat generation while maintaining equalization effectiveness.
2Loss of time
If all battery cells are discharged at the same time, then equalization processing is completed faster, but local temperature increase occurs
Solution Approach 1:
The controller implements periodic equalization processing by sequentially selecting different groups of battery cells for discharge at different time periods. The system monitors charge states and periodically switches between groups, creating a time-based periodic action pattern where each group undergoes equalization at appropriate intervals rather than all at once, thus distributing thermal load while completing the overall equalization task.
Solution Approach 2:
By segmenting battery cells into multiple groups and processing them sequentially rather than simultaneously, the patent reduces the concentration of thermal energy in any single location. Each group's discharge occurs in a distributed time pattern, preventing localized overheating while collectively achieving the equalization objective across the entire battery system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively equalizes battery cells while minimizing heat generation, enhancing reliability and extending battery life by preventing local temperature increases.
Implementation Method 1
This increases heat generation by the bypass resistors
Data Source
AI summary
A battery ECU acquires open circuit voltages of a plurality of battery cells that are divided into a plurality of groups A, B, C using a plurality of detecting units, and calculates SOCs of the battery cells based on the open circuit voltages. Then, the battery ECU selects the group to which the battery cell having the largest SOC among the SOCs of the plurality of battery cells belongs, and selects the battery cell to be discharged in the selected group. A series circuit composed of a resistor and a switching element is connected in parallel with each battery cell. The battery ECU turns on the switching element corresponding to the selected battery cell. At this time, the battery cell is connected to the resistor, thus being discharged.