Battery Power Management for Heterogeneous Second-Use EV Packs
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Solution Overview
Problem
Renewable energy sources like solar and wind power lack flexibility in meeting changing energy demands, necessitating energy storage systems to store and release electricity as needed, but existing battery management systems are inadequate in monitoring and controlling heterogeneous battery packs efficiently.
Innovation Solution
A battery power management unit (BPMU) is introduced, comprising a microcontroller, processors, and a system controller that reads data from internal battery management units, calculates state of charge and health, and transmits updated data to control charging/discharging, allowing for real-time monitoring and control of battery packs, including second-use EV batteries connected in parallel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing battery management systems are used to monitor heterogeneous battery packs, then system complexity is reduced, but monitoring precision and control reliability are insufficient
Solution Approach 1:
The system divides heterogeneous battery packs into multiple groups based on similar characteristics (capacity, voltage, current, temperature). Each group is monitored independently with tailored management strategies, allowing precise monitoring of each subset while managing overall system complexity through modular group-based control rather than individual cell management.
Solution Approach 2:
The BPMU implements a universal monitoring framework that handles multiple battery types (new batteries, second-use EV batteries) and multiple parameters (voltage, current, temperature, capacity) through a single integrated system. The system provides multi-functional capabilities including monitoring, control, and optimization across diverse battery configurations without requiring separate management systems for each battery type.
2Ease of manufacture
If second-use EV batteries are directly utilized without pre-selection or dismantling, then ease of manufacture and deployment are improved, but battery performance consistency and reliability deteriorate
Solution Approach 1:
The system performs preliminary classification and grouping of second-use EV batteries based on their electrical characteristics (capacity, voltage, current, temperature) before integration into the energy storage system. This preliminary action organizes batteries into homogeneous groups, ensuring performance consistency while maintaining the ease of direct deployment without physical dismantling or extensive pre-selection processes.
Solution Approach 2:
The system dynamically adjusts operational parameters (charging rates, discharging rates, temperature thresholds) for each battery group based on their specific characteristics. By changing control parameters rather than physical battery configurations, the system maintains reliability and performance consistency across heterogeneous second-use EV batteries while preserving deployment simplicity.
3Productivity
If real-time monitoring and control of heterogeneous battery packs is implemented, then energy storage flexibility and efficiency are improved, but device complexity and computational requirements increase
Solution Approach 1:
The system segments real-time monitoring and control operations into group-level operations rather than individual battery operations. By monitoring and controlling batteries in homogeneous groups with similar characteristics, the system achieves real-time efficiency for heterogeneous packs while reducing computational complexity through aggregated group management instead of individual cell management.
Solution Approach 2:
The system implements real-time monitoring and control at the group level rather than exhaustive individual cell-level control. This partial action approach focuses computational resources on critical group-level parameters (total capacity, average temperature, overall charge state) while maintaining energy storage efficiency, avoiding the excessive complexity of complete individual cell monitoring.
Data Source
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AI summary
A battery power management unit, BPMU (31), an electrical energy storage system (102) comprising one or more such BPMUs, and method of using the same are provided. The BPMU is configured to perform steps of: reading data from the internal battery management unit, BMU (25), of a respective battery pack (20) to establish capacity, an energy baseline, state of health (SOH), and an initial value of state of charge (SOC) of the respective battery pack, checking voltage and current at a time interval, calculating power of the respective battery pack, determining and updating battery date such as SOH and SOC, and transmitting updated battery data to a system controller (60) for controlling discharging power from or charging power to the respective battery pack. The battery pack (20) may be part of a grid-connected battery energy storage system (BESS) using second-use electric vehicle (EV) batteries.