Battery Balancing Apparatus Using Common Resistor and Switching Module
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Solution Overview
Problem
Existing battery packs face challenges in balancing battery cells connected in series due to inevitable state of charge imbalances, leading to reduced reversible capacity and accelerated degradation, and require a large number of resistor elements for balancing, which increases the pack size and can cause overheating.
Innovation Solution
An apparatus with a monitoring unit, a balancing unit featuring a common resistor element and a switching module, and a control unit that selectively connects battery cells to the resistor element based on voltage differences, allowing for balancing with a smaller number of resistor elements and reducing overheating by limiting simultaneous balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a balancing circuit including the same number of resistor elements as the battery cells is used to forcibly discharge battery cells having higher state of charge, then the state of charge imbalance between battery cells is equalized, but the entire size of the battery pack increases
Solution Approach 1:
The patent merges multiple resistor elements into a single common resistor element that is shared across multiple battery cells. Instead of having separate resistor elements for each battery cell, the invention uses one common resistor element with switching elements that connect different battery cells to it, thereby reducing the total number of resistor elements from N (where N is the number of battery cells) to just one.
Solution Approach 2:
The common resistor element serves multiple functions by being shared among multiple battery cells. Through the switching module, the same resistor element can be connected to different battery cells that require balancing, making it a universal component that performs the balancing function for multiple cells rather than having dedicated resistor elements for each cell.
2Productivity
If multiple battery cells are simultaneously balanced using a balancing circuit, then the balancing process is accelerated, but drastic heat emission occurs requiring additional heat dissipation structures
Solution Approach 1:
The patent implements periodic or sequential action by using switching elements that enable balancing of multiple battery cells in a controlled sequence rather than all at once. The switching module can connect battery cells to the common resistor element one at a time or in controlled groups, allowing the heat generation to be distributed over time and preventing drastic simultaneous heat emission while still achieving relatively fast balancing through rapid switching between cells.
3Volume of stationary object
If the number of resistor elements is reduced to decrease battery pack size, then the overall dimensions are minimized, but the ability to balance multiple battery cells simultaneously is limited
Solution Approach 1:
The patent introduces dynamic switching capability through switching elements (such as MOSFETs or relays) that allow the single common resistor element to be dynamically connected to different battery cells. This dynamic reconfiguration enables the system to balance multiple cells sequentially or in controlled groups, maintaining high balancing capacity despite using minimal resistor elements. The switching module dynamically changes the circuit topology to adapt to different balancing needs.
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 enables selective discharge of one or more battery cells using fewer resistor elements, reducing the overall size of the battery pack and preventing overheating without the need for additional heat dissipation structures.
Implementation Method 1
a voltage detection circuit configured to detect a voltage of each of the plurality of battery cells
Implementation Method 2
a first common resistor element connected between a first common node and a second common node... selectively connect a positive electrode terminal of each battery cell to the first common node... selectively connect a negative electrode terminal of each battery cell to the second common node
Data Source
AI summary
An apparatus including a monitoring unit including a voltage detection circuit which detects a voltage of the plurality of battery cells, a balancing unit including a first common resistor element and a switching module, the first common resistor element connected between a first common node and a second common node, and a control unit operably coupled to the monitoring unit and the switching module, the control unit determining a balancing target including at least one of the plurality of battery cells based on the voltage of each of the plurality of battery cells, controlling the switching module to form a current channel between the first common resistor element and the balancing target and determining a maximum number of battery cells that can be included in the balancing target based on resistance of the first common resistor element and the voltage of each of the plurality of battery cells.