Battery Pack Controller for Over-Discharge Protection
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Solution Overview
Problem
Existing battery management systems in portable electric tools fail to accurately detect and prevent states similar to over-discharge, leading to battery deterioration and reduced lifespan due to capacity deviations among battery cells and non-operational states with continued power supply.
Innovation Solution
A device comprising a battery pack with a protection circuit module, an operator, and a controller that includes sensors for current and voltage detection, an operation detector, and a temperature sensor, which determines the state of the battery cell by monitoring power transfer and voltage levels, and performs a protection process after a calculated delay time inversely proportional to temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the battery management system uses a simple voltage threshold detection method, then the device complexity is reduced, but the measurement precision of over-discharge state detection deteriorates
Solution Approach 1:
The patent applies dynamics by making the detection threshold dynamic rather than fixed. The system adjusts the voltage threshold based on the battery's temperature and charge history, allowing the threshold to adapt to different operating conditions. This resolves the contradiction by maintaining simple detection hardware while achieving high measurement precision through dynamic threshold adjustment.
Solution Approach 2:
The system changes detection parameters (voltage threshold, time duration) based on operating conditions such as temperature and load history. By varying these parameters dynamically, the system achieves accurate over-discharge detection without requiring complex hardware, thus resolving the contradiction between simplicity and precision.
2Measurement precision
If the battery management system implements comprehensive monitoring of multiple parameters, then the measurement precision of battery state detection is improved, but the device complexity increases
Solution Approach 1:
The patent segments the monitoring process into distinct functional modules: voltage detection unit, temperature detection unit, timing unit, and control unit. Each module performs a specific function, which simplifies the overall system design while achieving comprehensive monitoring. This modular segmentation resolves the contradiction by making the complex monitoring system manageable and implementable.
Solution Approach 2:
The controller performs multiple functions using a single integrated unit: it detects voltage, detects temperature, determines timing, and controls the discharge protection. This multi-functionality reduces the need for separate dedicated components for each function, thereby improving measurement precision without proportionally increasing device complexity.
3Reliability
If the protection process is triggered immediately upon detecting low voltage, then the reliability of battery protection is improved, but the loss of time for legitimate operation increases
Solution Approach 1:
The system performs preliminary monitoring and evaluation before triggering protection. It detects the low voltage state, checks the duration of the state, considers temperature conditions, and evaluates load history before activating the protection mechanism. This preliminary action ensures reliable protection while avoiding premature interruption of legitimate operations, thus resolving the contradiction between reliability and time loss.
Solution Approach 2:
The system takes preliminary anti-action by preparing protection measures in advance through continuous monitoring of multiple parameters. When conditions indicate potential over-discharge, the system pre-adjusts thresholds and prepares control actions, allowing for smooth transition to protection mode without sudden operational interruptions, thereby balancing reliability with minimal time loss.
4Measurement precision
If the battery management system accounts for temperature effects on voltage, then the measurement precision of state detection is improved, but the device complexity increases
Solution Approach 1:
The patent introduces temperature as an intermediary parameter that mediates between actual battery voltage and the perceived voltage state. By measuring temperature and using it to adjust voltage thresholds, the system compensates for temperature effects without requiring complex direct modeling of the temperature-voltage relationship. This intermediary approach improves measurement precision while keeping the system relatively simple.
Data Source
AI summary
An Electric tool with a controller for a battery pack and a control method thereof. The electric tool includes a battery pack, an operator and a controller The battery pack includes a plurality of battery cells and a protection circuit module detects and controls a state of charge and discharge of a plurality of battery cells. The operator receives power from the battery pack and converts the received power into physical energy. The controller controls the protection circuit module so as to perform a protection process of the battery pack in a state similar to over-discharge caused in the case in which the power is transferred from the battery pack to the operator and at the same time, the operator does not continuously operate.