Battery Controller Sync Pulse for Multi-Cell Sampling
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Solution Overview
Problem
Synchronizing measurements across multiple battery cells in electric vehicles is challenging due to high-voltage levels and the need for accurate, simultaneous data collection, especially when using multiple monitoring ICs, which can result in delays and missed measurements.
Innovation Solution
A primary controller generates a sync pulse at fixed intervals, and a secondary controller receives this pulse to start a pulse generator operating at a predetermined multiple of the primary frequency, allowing it to schedule a secondary sampling moment accurately, ensuring synchronization and advance preparation for measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an externally generated timing pulse is distributed to each BPSM to trigger simultaneous sampling, then synchronization of measurements is improved, but the system cannot provide advance notification to allow preparatory steps in IC and may miss measurements if timing signal fails
Solution Approach 1:
The patent applies preliminary action by allowing the BPSM to internally generate the sampling moment trigger before the actual sampling occurs. The BPSM receives a multiplex message from the BECM and uses its internal time reference to prepare for sampling in advance, ensuring that preparatory steps can be taken in the IC before measurements are taken. This resolves the contradiction by enabling both synchronization (through coordinated triggering) and reliability (through advance preparation and internal verification).
2Reliability
If a BECM generates sampling moment internally and sends multiplex message to BPSM, then advance notification is provided for preparatory steps, but inherent delays in message arbitration and transmission create undesirable delays between primary and secondary sampling moments
Solution Approach 1:
The BPSM performs preliminary actions by internally generating the sampling trigger based on its own time reference after receiving the multiplex message. This allows the BPSM to prepare for sampling without waiting for the actual sampling moment from the BECM, thereby reducing the time delay while still maintaining coordinated sampling across multiple BPSMs.
Solution Approach 2:
The patent transitions from a centralized timing approach (BECM generates all triggers) to a distributed timing approach (each BPSM generates its own trigger based on internal reference). This dimensional change in control architecture eliminates the transmission and arbitration delays inherent in the centralized approach while maintaining synchronization through the coordinated multiplex message protocol.
3Quantity of substance
If multiple monitoring ICs are used to monitor over one hundred cells, then the monitoring capability is improved, but coordinating signals between separate BPSMs becomes necessary and complex
Solution Approach 1:
The patent applies segmentation by dividing the battery monitoring system into multiple independent BPSM units, each capable of autonomously managing a subset of battery cells. Each BPSM contains its own time reference and can independently generate sampling triggers, reducing the coordination complexity between units while enabling monitoring of a large number of cells through the modular architecture.
Solution Approach 2:
Each BPSM is designed as a universal module that can monitor multiple battery cells and independently generate synchronized sampling triggers. This multi-functionality allows the system to scale to monitor over one hundred cells using multiple identical BPSM units, each performing the same functions, thereby reducing coordination complexity through standardization.
Data Source
AI summary
A multi-cell battery pack in an electric vehicle is monitored by multiple sensing modules. A primary controller is coupled to a first plurality of cells to measure a predetermined parameter of each cell. The primary controller determines a sampling moment recurring at a fixed frequency for sampling the predetermined parameter of each of the first plurality of cells. The primary controller generates a sync pulse at each sample moment. A secondary controller is coupled to a second plurality of cells to measure the predetermined parameter of each cell. The secondary controller receives the sync pulse to start a pulse generator operating at a frequency which is a predetermined multiple of the primary controller fixed frequency. The secondary controller counts pulses generated by the pulse generator and schedules a synchronized secondary sampling moment according to a predetermined pulse count.