Battery Heating Element for Cold Weather Talk Time
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Solution Overview
Problem
Battery performance and talk time are significantly reduced at low temperatures, making it challenging for network access devices in vehicles to maintain communication in cold conditions without increasing battery size or cost.
Innovation Solution
Incorporating a heating element, such as an etched trace on a flexible substrate, to maintain battery temperature above a minimum operating threshold, which also serves as a diagnostic load to measure output impedance, and using a secondary power source like the vehicle's alternator to power the heating element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the battery size and capacity are increased to maintain talk time at low temperatures, then the battery performance is improved, but the package size and cost increase
Solution Approach 1:
The patent changes the temperature parameter of the battery by introducing a heating element. By elevating the battery temperature 20-30°C above ambient (maintaining it between 0°C and 45°C), the battery's output impedance is reduced and its capacity is increased, allowing standard-size batteries to achieve the required talk time performance in cold environments without increasing package size
Solution Approach 2:
The heating element serves multiple functions: it heats the battery to maintain optimal temperature for performance, and it also functions as the discharge load for measuring output impedance to determine battery end-of-life. This multi-functionality eliminates the need for separate heating and diagnostic components, reducing overall package size
2Duration of action of moving object
If the battery size and capacity are increased to maintain talk time at low temperatures, then the battery performance is improved, but the cost increases
Solution Approach 1:
By changing the temperature parameter through the heating element, standard-size batteries can achieve enhanced performance in cold environments. This avoids the need for expensive large-capacity batteries designed specifically for cold-weather operation, thereby reducing cost while maintaining talk time requirements
Solution Approach 2:
The heating element doubles as the diagnostic load for measuring output impedance, eliminating the need for separate heating components and reducing overall system cost. The etched trace on flexible substrate provides a cost-effective heating solution that can be contoured to match cell geometry
3Temperature
If the heating element is powered from the backup battery, then the battery temperature is maintained, but the battery capacity is reduced due to self-discharge
Solution Approach 1:
The heating element serves dual purposes: maintaining battery temperature and acting as the discharge load for output impedance measurement. When powered from the secondary power source, it prevents backup battery self-discharge while still providing necessary heating, thus preserving battery capacity
Solution Approach 2:
The secondary power source (vehicle battery or alternator) acts as an intermediary, providing power to the heating element during vehicle operation. This prevents the backup battery from discharging to power the heater, preserving its capacity for emergency communication while still maintaining optimal temperature through the vehicle's power system
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
This solution ensures extended talk time and improved battery performance by maintaining optimal temperature and utilizing secondary power sources to minimize battery discharge, addressing the limitations of existing battery technologies in cold environments.
Implementation Method 1
Elevating the temperature of the battery pack by 20° C. to 30° C. above ambient can be accomplished by placing a heating element in close proximity to the case of the cell
Implementation Method 2
Battery packs can incorporate some type of temperature sensor which is mounted in close proximity of the battery cell and may even be thermally coupled to the battery cell
Implementation Method 3
One technique used to measure the output impedance is to measure the change in voltage with the battery unloaded and also when a load is connected. By measuring the open circuit voltage as well as the voltage under load and knowing the load impedance, the output impedance of the battery can be calculated
Data Source
AI summary
A system and method for controlling battery conditions. The system includes a network access device battery. The network access device battery powers a network access device. A heating element may be connected to the network access device battery. The heating element may be a resistive load for determining a status of the network access device battery or the heating element may be activated based on a heating schedule.