Battery Self-Warming via Variable Current Discharge
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in being charged at low temperatures, as existing methods either require material changes or dedicated heaters, which are costly and inefficient, and existing technologies either reduce battery capacitance or fail to maintain a chargeable state below freezing temperatures.
Innovation Solution
A battery device with a temperature detector and controller that performs variable current discharge, increasing discharge current as temperature rises, allowing the battery to reach a chargeable state without material changes or dedicated heaters by using self-discharge and heater resistors for balance correction and warming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If material changes or dedicated heaters are used to enable charging at low temperature, then charging capability at low temperature is improved, but device complexity and cost increase
Solution Approach 1:
The battery device uses its own internal resistance to generate heat through discharge, warming itself to a chargeable temperature without requiring external heaters or material changes. The control unit manages this self-warming process by controlling discharge current based on detected temperature, enabling the battery to service its own heating needs.
Solution Approach 2:
The control unit changes the discharge current parameter dynamically based on temperature detection. When temperature is below the chargeable threshold, the control unit increases discharge current to generate sufficient heat; when temperature reaches the threshold, discharge current is reduced or stopped. This parameter adjustment enables adaptive temperature management.
2Loss of energy
If variable current discharge is performed to warm the battery, then warming efficiency is improved, but discharge time increases
Solution Approach 1:
The discharge current is made dynamic rather than constant. The control unit continuously monitors temperature and adjusts discharge current in real-time, increasing current when heating is needed and decreasing or stopping it when the chargeable temperature is reached. This dynamic control optimizes both heating efficiency and time management.
Solution Approach 2:
The system implements feedback control where the control unit detects battery temperature and uses this information to regulate discharge current. The detected temperature feeds back to the control unit, which adjusts discharge parameters accordingly, creating a closed-loop control system that prevents overheating and optimizes warming time.
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
Enables efficient warming of the battery to a chargeable state at low temperatures, reducing discharge time and capacitance loss, and eliminating the need for material changes or dedicated heaters, thus enhancing charging capabilities in cold environments.
Implementation Method 1
perform variable current discharge on the battery when the temperature detector detects a constant temperature range immediately before a start of charge
Implementation Method 2
a second balance correction circuit having a second switch configured to perform balance correction and connected to each of the secondary batteries of the assembled battery and a plurality of heater resistors to which a current flowing through the second switch is supplied
Data Source
AI summary
A battery device is provided. The battery includes a temperature detector configured to detect a temperature of a battery and a controller configured to perform variable current discharge on the battery when the temperature detector detects a constant temperature range immediately before a start of charge.