Battery Pack Internal Heating for Cold-Weather Charging
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Solution Overview
Problem
Battery packs struggle to charge in cold weather due to temperature limitations, leading to potential damage and reduced functionality, as existing solutions either prevent charging below a certain threshold or require lengthy external heating methods that may not effectively raise the battery cell temperature.
Innovation Solution
Incorporating a heating element and temperature sensing device within the battery pack, controlled by an electronic processor to maintain or exceed the charging threshold temperature, allowing for safe and efficient charging in cold conditions, and implementing a method to discharge battery cells through resistors in case of failure conditions to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external heating methods are used to warm the battery pack, then the battery pack can be charged in cold temperatures, but the heating time is excessively long and thermal transfer is insufficient
Solution Approach 1:
The heating function is extracted from the external charger and integrated directly into the battery pack as an internal heating element. This allows the heating element to be positioned in direct contact with the battery cell, enabling rapid temperature increase from below freezing to above 0°C within minutes, compared to the excessively long heating time required by external methods.
Solution Approach 2:
A thermal interface material is introduced as an intermediary between the heating element and the battery cell to ensure efficient thermal transfer. This mediator maximizes the thermal contact and heat transfer efficiency, allowing the heating element to rapidly warm the battery cell to the charging threshold temperature.
2Reliability
If the battery pack prevents charging below the temperature threshold, then battery cell damage is avoided, but charging cannot be performed in cold weather
Solution Approach 1:
The heating element is activated before charging begins to pre-warm the battery cell to the minimum threshold temperature. The control circuitry monitors the temperature and only enables charging once the battery cell reaches the safe operating temperature, thus preventing cell damage while enabling cold-weather charging capability.
Solution Approach 2:
The control circuitry continuously monitors the battery cell temperature and uses this feedback to control the heating element and charging process. The system adjusts the heating power and charging current based on real-time temperature readings, ensuring the battery cell remains within the safe operating range while enabling charging in cold environments.
3Adaptability or versatility
If low charging current is used in cold temperatures, then charging can proceed, but charging time increases up to three times
Solution Approach 1:
The heating element is activated in advance to warm the battery cell to the optimal temperature range before charging begins. This preliminary heating action enables the use of higher charging currents during the charging process, maintaining fast charging speeds even in cold environmental conditions without risking cell damage.
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 battery packs to charge efficiently in cold temperatures by maintaining the necessary temperature for charging and preventing damage through controlled heating, while also addressing failure conditions by discharging cells to prevent further damage.
Implementation Method 1
one or more heating elements supported in the housing and operable to heat the battery cell
Implementation Method 2
one or more resistors supported in the housing and operable to discharge the battery cell through the one or more heating elements
Data Source
AI summary
A battery pack, a method of heating a battery cell and an electrical combination. The battery pack may include a housing; a battery cell; a heating element operable to provide heat to the battery cell; a temperature sensing device operable to sense a temperature of an interior of the battery pack; a heating switch operable to control whether power is provided to the heating element; and an electronic processor configured to receive a signal from the temperature sensing device, the signal indicating the temperature of the interior of the battery pack, determine that the temperature of the interior of the battery pack is less than a predetermined temperature threshold, and in response to determining that the temperature of the interior of the battery pack is less than the predetermined temperature threshold, close the heating switch to provide power to the heating element.