Electric Tool Battery Thermal Control via Voltage-Adaptive Thresholds
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Solution Overview
Problem
Conventional electric tools with temperature control mechanisms for battery packs fail to effectively prevent battery cell deterioration due to temperature increases, especially when using high-rated voltage battery packs, as the temperature threshold values are not adequately adjusted for varying rated voltages, leading to potential overheating and accelerated degradation.
Innovation Solution
An electric tool with a controller that monitors battery cell temperature and adjusts the driving unit's output based on rated voltage-specific temperature threshold values, including a mechanism to count consecutive temperature exceedances, ensuring timely limitation of the driving unit's output to prevent overheating, even when the rated voltage information is unclear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature threshold value is set for battery protection, then battery cell deterioration is prevented, but high-rated voltage battery packs experience temperature overshoot and still reach high temperatures
Solution Approach 1:
The patent applies dynamics by making the temperature threshold value changeable based on battery pack characteristics. Specifically, the controller dynamically adjusts the temperature threshold according to the rated voltage of the battery pack - using a lower threshold for high-rated voltage packs (e.g., 18V) compared to standard packs (e.g., 14.4V). This dynamic adjustment prevents temperature overshoot in high-voltage batteries by triggering output limitation earlier in the temperature rise process.
Solution Approach 2:
The patent implements parameter changes by modifying the temperature threshold parameter based on the rated voltage parameter of the battery pack. The system stores multiple temperature threshold values corresponding to different rated voltages and selects the appropriate threshold based on the detected battery pack specifications. This parameter adaptation ensures that high-rated voltage battery packs, which heat up faster, operate with a more conservative temperature limit.
2Temperature
If the temperature threshold value is lowered to prevent overshoot in high-rated voltage battery packs, then temperature control improves, but standard-rated voltage battery packs may experience unnecessary output limitation
Solution Approach 1:
The patent applies local quality by providing different temperature threshold values for different battery pack types rather than using a single universal threshold. The system stores multiple threshold values (e.g., first threshold for 18V packs, second threshold for 14.4V packs) and applies the appropriate threshold based on the specific battery pack's rated voltage. This localized approach ensures each battery type operates with an optimally tailored threshold that prevents both overheating and unnecessary output limitation.
Solution Approach 2:
The system changes the temperature threshold parameter based on the rated voltage parameter of the battery pack. By detecting the battery pack's rated voltage and selecting the corresponding threshold from stored values, the system adapts the temperature control parameter to match the specific battery characteristics, avoiding both overheating in high-voltage packs and false triggering in standard-voltage packs.
3Reliability
If temperature detection and control is implemented, then battery safety is improved, but device complexity increases due to additional sensors and control logic
Solution Approach 1:
The patent applies self-service by having the battery pack itself provide the rated voltage information to the controller through its own internal storage and output units. The battery pack includes a rated voltage storage unit that holds the rated voltage value and a rated voltage information output unit that transmits this information to the controller. This self-identification mechanism eliminates the need for complex external detection circuits, allowing the system to automatically select the appropriate temperature threshold based on information provided by the battery pack itself.
Solution Approach 2:
The controller serves multiple functions: it controls the driving unit output, detects battery temperature, receives rated voltage information from the battery pack, and selects appropriate temperature thresholds based on this information. By integrating these diverse functions into a single controller unit, the system avoids the need for separate dedicated circuits for each function, thereby reducing overall device complexity while maintaining comprehensive battery protection capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents battery pack deterioration by dynamically adjusting temperature threshold values and output limitations based on rated voltage, reducing the risk of overheating and extending battery life, especially in high-rated voltage scenarios.
Implementation Method 1
a battery temperature detection unit for detecting a temperature of the battery cell
Implementation Method 2
when a current flows in the battery cell, the battery cell emits heat. The heat emission from the battery cell occurs during electric discharge as well as during electric charge.
Data Source
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AI summary
This electric tool is provided with: a battery pack (1) that includes a battery cell; and an electric tool main body (3) in which a driving unit (4) is driven by power supplied from the battery pack (1). The electric tool main body (3) is provided with a controller (5) that controls the driving unit (4). The battery pack (1) is provided with: a rated voltage storage unit (12) at which information of a rate voltage of the battery pack is stored; a rated voltage information output unit (13) that outputs the information of the rated voltage stored at the rated voltage storage unit to the controller (5); a battery temperature detection unit (14) that detects the temperature of the battery cell (11); and a detected temperature output unit (15) that outputs the temperature value detected by the battery temperature detection unit (14) to the controller (15). The controller (5) limits the output of the driving unit (4) when the temperature value of the battery cell (11) exceeds a temperature threshold value determined in accordance with the rated voltage.