Modular Battery Pack Current Protection for Parallel Capacity Expansion
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Solution Overview
Problem
Existing battery packs have limited battery capacity and require replacement when performance deteriorates, leading to inconvenience and inefficiency.
Innovation Solution
A battery pack system with an extended battery module and a battery management system (BMS) that determines current protection levels and stabilizes the extended capacity by integrating additional battery modules in parallel, using AFE circuits for sensing and communication via CAN protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery cells are fixed in the battery pack, then the battery pack structure is simple and reliable, but the battery capacity is limited and cannot be extended
Solution Approach 1:
The battery pack is divided into a main battery module and an extended battery module that can be independently connected or disconnected. The extended battery module includes its own battery cells arranged in series/parallel configurations, allowing capacity extension without redesigning the entire battery pack structure.
Solution Approach 2:
The battery pack is designed with universal connection terminals and control circuits that can accommodate both the main battery module and the extended battery module. The same connection terminals and control logic are used whether the extended module is connected or disconnected, providing multi-functional capability.
2Duration of action of moving object
If the battery capacity is extended by adding more battery cells, then the battery use time increases, but the battery pack becomes more complex and harder to control
Solution Approach 1:
The control circuits of the main battery module and the extended battery module are merged into a single integrated control system. The same BMS controller manages both modules, using unified control logic for charging, discharging, and protection, thereby extending battery use time without proportionally increasing control system complexity.
Solution Approach 2:
The BMS implements feedback control by continuously monitoring the state of charge, voltage, and current of both the main and extended battery modules. Based on this feedback, the controller dynamically adjusts the operating parameters to optimize battery use time while maintaining safe operation.
3Quantity of substance
If the extended battery module is connected in parallel, then the battery capacity increases, but the current management becomes more difficult and protection becomes more complex
Solution Approach 1:
The BMS implements dynamic current management by continuously adjusting the current distribution between the main and extended battery modules based on their real-time state. The controller can dynamically switch between modules or adjust current ratios to optimize capacity utilization while maintaining reliable protection.
Solution Approach 2:
The system changes operational parameters such as current thresholds, voltage limits, and protection levels based on the connection state of the extended battery module. When the extended module is connected, the BMS adjusts the current protection parameters to account for the increased total capacity and different discharge characteristics.
4Ease of operation
If fixed battery cells are used in the battery pack, then the manufacturing process is simple, but replacing the battery pack when performance deteriorates is inconvenient
Solution Approach 1:
The battery system is segmented into a permanent main battery module and a replaceable extended battery module. When performance deteriorates, only the extended module needs to be replaced rather than the entire battery pack, improving replacement convenience while keeping the manufacturing process relatively simple.
Solution Approach 2:
The extended battery module is designed as a consumable component that can be discarded when depleted and replaced with a fresh module. The main battery module and connection infrastructure are recovered and retained, reducing waste and simplifying the replacement process.
Data Source
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AI summary
A battery pack includes: a pair of external terminals; a pair of first connection terminals; a first battery comprising a plurality of first battery strings connected in parallel between the pair of first connection terminals, each of the plurality of first battery strings comprising a plurality of first battery cells connected in series; an extended battery module comprising a pair of second connection terminals detachably connected to the pair of first connection terminals, and a second battery comprising a plurality of second battery strings connected in parallel between the pair of second connection terminals; and a battery management system (BMS) configured to determine a current protection level based on a total number of the plurality of first battery strings and the plurality of second battery strings, in response to the extended battery module being connected to the pair of first connection terminals.