Battery Module Current Sensing with Busbar Cross-Validation
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Solution Overview
Problem
Existing energy storage systems face challenges in accurately measuring and diagnosing system current to ensure safety and reliability, particularly due to inconsistencies in voltage and resistance across busbars and the impact of static electricity and interference.
Innovation Solution
The system incorporates a shunt resistor connected to a controller, with first cell monitoring units collecting busbar status information, RC filters for data accuracy, inductors for interference reduction, capacitors for static protection, and analog-to-digital converters for precise current detection, along with a two-way communication system for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shunt resistor is used to measure system current, then current measurement is achieved, but measurement precision is insufficient due to voltage and resistance inconsistencies across busbars
Solution Approach 1:
The patent segments the current measurement function into multiple independent measurement paths: one through the shunt resistor for system current and another through the busbar status information for module current. Each path operates independently and can be cross-validated, improving both precision and reliability by eliminating single-point failure and reducing the impact of voltage/resistance inconsistencies in any single measurement path.
2Reliability
If basic current collection is implemented, then system operation is enabled, but safety and reliability are compromised due to static electricity and interference
Solution Approach 1:
The patent implements protective measures beforehand by introducing RC filter circuits and inductors in the signal collection paths. These components are designed to cushion against static electricity and electromagnetic interference before they can corrupt the measurement signals, ensuring that the data collected from both the shunt resistor and busbar status information remains clean and reliable for safety-critical current diagnosis.
3Measurement precision
If data collection from busbar status information is added, then current diagnosis accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing busbar status information collection circuit serve multiple functions: it continues to monitor busbar health while simultaneously providing an alternative current measurement path. This multi-functionality allows the system to extract current information from busbar voltage drops without adding dedicated hardware, thereby improving diagnosis accuracy while minimizing the increase in device complexity.
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
Enhances the accuracy of current measurement and diagnosis, improving safety and reliability by stabilizing voltage levels, reducing false alarms, and ensuring precise current detection through enhanced data collection and communication.
Implementation Method 1
A shunt resistor is disposed on a main circuit of the energy storage system. The shunt resistor is connected to a controller. The current of the energy storage system is collected by the shunt resistor.
Implementation Method 2
The battery monitoring circuit board includes a first resistor, a second resistor, and a first capacitor. The first resistor is electrically connected between the first terminal and the first pin. The second resistor is electrically connected between the second terminal and the second pin. A first end of the first capacitor is electrically connected to the first pin. A second end of the first capacitor is electrically connected to the second pin.
Implementation Method 3
The battery monitoring circuit board includes a first inductor and a second inductor. The first inductor is electrically connected between the first resistor and the first terminal. The second inductor is electrically connected between the second resistor and the second terminal.
Implementation Method 4
A first end of the first capacitor is electrically connected to the first pin. A second end of the first capacitor is electrically connected to the second pin.
Implementation Method 5
analog-to-digital converters for precise current detection
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An energy storage system includes: a plurality of battery modules connected in series, where each battery module includes at least two cell modules and a first cell monitoring unit, and, in each battery module, adjacent cell modules are electrically connected by a busbar, and the busbar is electrically connected to one first cell monitoring unit; a controller, communicatively connected to the first cell monitoring unit; and a shunt resistor, disposed on a main circuit of the energy storage system. The shunt resistor is electrically connected to the controller.