Secondary Cell State Detector with Dynamic Switching
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Solution Overview
Problem
Existing secondary cell state detectors struggle to accurately measure the state of multiple secondary cells in an assembled battery, as they often include a cell voltage connected to ground, leading to inaccurate measurements.
Innovation Solution
A secondary cell state detector design that includes a first and second condenser, each connected to one-side electrodes of the cells, with switch control units to alternate connections between the condensers and differential amplifier circuits, allowing for accurate detection of internal resistance and state of health across multiple cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one plate of the condenser is connected to ground for detection, then the detection circuit is simplified, but accurate measurement cannot be performed for cells other than the one closest to ground
Solution Approach 1:
The patent applies the dynamics principle by making the ground connection dynamic rather than static. The switch control unit dynamically connects different cells to the ground reference potential at different times during the detection process. This allows the detection circuit to accurately measure voltages across all cells in the series-connected battery by sequentially establishing each cell as the reference, thereby resolving the contradiction between circuit simplicity and measurement accuracy for multiple cells.
2Measurement precision
If multiple condensers are used to hold voltages of multiple cells, then measurement accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent applies the merging principle by combining multiple detection functions into a single condenser and switch control unit. Instead of allocating separate condensers to each cell, the system uses one condenser that is sequentially connected to different cells through the switch control unit. This allows the same hardware components to serve multiple detection purposes, thereby improving measurement accuracy without proportionally increasing device complexity or cost.
Solution Approach 2:
The patent applies the universality principle by designing the single condenser and switch control unit to perform multiple detection functions. The same condenser is used to hold voltages from different cells at different times, and the switch control unit routes signals from multiple cells to this single condenser. This multi-functional design achieves accurate detection of internal resistance across all cells while minimizing the number of required components.
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
Enables precise detection of secondary cell states in assembled batteries, reducing costs by eliminating the need for additional components and hardware, while ensuring accurate measurement and equalization of electrode voltages.
Implementation Method 1
a first condenser Co1 and a second condenser Co2, respectively. One-side plates of the first condenser Co1 and the second condenser Co2 are connected to one-side negative electrodes of the secondary cells Ce1 and Ce2
Implementation Method 2
a differential amplifier circuit 6 that outputs a differential voltage of voltages of the other-side plates of the first condenser Co1 and the second condenser Co2
Data Source
AI summary
One-side plates of first and second condensers are connected to a one-side electrode of one of a plurality of secondary cells. First switches connect the other-side electrode of the secondary cell to the other-side plate of one of the first condenser and the second condenser. An MCU controls the first switches to connect the other-side electrode of the secondary cell to the other-side plate of the first condenser when the plurality of secondary cells is in a first state, and then connect the other-side electrode of the secondary cell to the other-side plate of the second condenser when the plurality of secondary cells is in a second state. A differential amplifier circuit outputs a differential voltage of voltages of the other-side plates of the first condenser and the second condenser. A cell monitoring IC detects states of the secondary cells based on the differential voltage.