Distributed BMS Clock Synchronization for Impedance Measurement
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Solution Overview
Problem
Existing battery management systems face challenges in achieving synchronization across scattered BMS ICs due to the lack of a common clock distribution via daisy chain or wireless protocols, hindering accurate electrochemical impedance measurements.
Innovation Solution
A battery management system with a synchronization element and measurement devices that utilize a reference clock signal to synchronize local oscillators through a communication network, adjusting individual clock signals based on time reference signals to ensure synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If BMS ICs are scattered over the battery pack and connected via daisy chain communication bus or wireless protocol, then device distribution and flexibility are improved, but synchronization precision deteriorates due to inability to distribute common clock
Solution Approach 1:
The patent introduces a synchronization message as an intermediary carrier that transports timing information through the existing daisy-chain communication bus. This mediator enables synchronization without requiring a separate common clock distribution infrastructure, thus resolving the contradiction between distributed architecture and synchronization precision.
Solution Approach 2:
The daisy-chain communication bus is made multi-functional by using it both for data communication and for distributing synchronization timing information. This universal usage eliminates the need for separate clock distribution channels while maintaining synchronization accuracy across distributed BMS ICs.
2Measurement precision
If a common clock distribution system is implemented, then synchronization precision is improved, but device complexity and system cost increase
Solution Approach 1:
Each BMS IC generates and transmits its own synchronization messages based on its local clock, and other ICs adjust their timing based on received messages from their neighbors. This self-service approach eliminates the need for a centralized clock distribution system while achieving synchronization through distributed autonomous adjustment.
Solution Approach 2:
The synchronization function is merged with the existing communication bus infrastructure rather than being implemented as a separate system. By combining timing distribution with data communication in the same physical medium, the patent avoids the complexity and cost of dual infrastructure while achieving precise synchronization.
3Ease of manufacture
If daisy chain communication bus is used for connecting BMS ICs, then ease of manufacture and installation are improved, but synchronization capability deteriorates due to lack of common clock distribution
Solution Approach 1:
The synchronization system dynamically adapts to the daisy-chain topology by having each node synchronize with its predecessor and propagate timing information forward. This dynamic distributed synchronization mechanism maintains reliability while preserving the simple daisy-chain physical layout that enables easy manufacture and installation.
Data Source
AI summary
A battery management system comprising: a synchronisation element comprising an oscillator wherein the synchronisation element is configured to generate a reference clock signal based on an output of the oscillator; and a plurality of measurement devices wherein each measurement device is configured to measure an electrical property of one or more battery cells and comprises a local oscillator configured to generate an individual clock signal; and wherein the plurality of measurement devices are connected in a communication network with the synchronisation element, and wherein: the synchronisation element is configured to send, by the communication network, time reference signals to the plurality of measurement devices based on the reference clock signal; each measurement device is configured to compare each time reference signal to its individual clock signal and, based on any detected difference, adjust its local oscillator to synchronize the individual clock signal with the reference clock signal.