Integrated Voltage Sensor and Charge Equalizer for Battery Modules
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Solution Overview
Problem
Existing battery management systems for series-connected battery strings face challenges in reducing volume and minimizing voltage stress on switch modules as the number of batteries increases, due to separate voltage sensors and charge equalizers, leading to inefficiencies and potential over-charging issues.
Innovation Solution
A battery management system where the switch module is shared between the voltage sensor and charge equalizer in a time-division manner, with a microprocessor controlling the connection of each battery to either the sensor or equalizer, reducing the overall volume and stress on the switch module by integrating the voltage sensor with the charge equalizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate voltage sensors and charge equalizers are used for each battery, then voltage measurement and charge equalization can be performed independently, but the total volume of the battery management system increases
Solution Approach 1:
The patent combines the voltage sensor and charge equalizer into a single integrated circuit module. The voltage sensor includes an operational amplifier that shares common components (resistors, capacitors, power supply) with the charge equalizer function, allowing both voltage measurement and charge equalization to be performed by the same physical hardware rather than requiring separate independent circuits for each battery.
Solution Approach 2:
The integrated circuit module performs multiple functions: it measures battery voltage through the operational amplifier, provides charge equalization current to undercharged batteries, and discharges overcharged batteries. This multi-functional design eliminates the need for separate dedicated sensors and equalizers for each battery, reducing overall system volume while maintaining full functionality.
2Reliability
If multiple charge equalizers are provided for series-connected batteries, then charge equalization can be performed on each battery, but the device complexity increases
Solution Approach 1:
The patent merges the voltage sensing function and charge equalization function into a single operational amplifier-based circuit. The operational amplifier serves dual purposes: it senses battery voltage through its input terminals and simultaneously drives the charge equalization current through its output terminal, eliminating the need for separate sensing circuits and equalizer circuits for each battery.
Solution Approach 2:
The operational amplifier in the integrated module performs multiple functions: voltage sensing, voltage comparison, charge equalization current generation, and battery discharge control. This universal component approach significantly reduces device complexity compared to using separate dedicated components for each function on each battery.
3Ease of operation
If a switch module controls connection to multiple batteries, then voltage sensing and charge equalization can be managed, but voltage stress on the switch module increases
Solution Approach 1:
The patent divides the battery management function into individual battery management units, where each unit handles one battery independently. The switch module only needs to switch between individual batteries rather than managing all batteries simultaneously, reducing the voltage stress on each switch. The operational amplifier in each unit operates at individual battery voltage levels rather than total string voltage.
Solution Approach 2:
The operational amplifier serves as an intermediary between the battery and the control system. It buffers the voltage signal from the battery, providing voltage sensing capability without requiring the switch module to directly handle high-voltage switching for both sensing and equalization. This intermediary function protects the switch module from excessive voltage stress.
Data Source
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AI summary
A battery management system according to the present invention comprises a battery module consisted of a plurality of batteries connected in series; a switch module connected in parallel to the battery module; a voltage sensor measuring a voltage of each battery composing the battery module; a charge equalizer causing each battery composing the battery module to be charged, discharged or charged/discharged; and a microprocessor controlling the switch module to determine whether to charge or discharge each battery composing the battery module according to the voltage values measured by the voltage sensor and; wherein the voltage sensor and the charge equalizer are connected in parallel to each battery composing the battery module by the switch module.