Self Heating Battery System for Cold Ambient Backup
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Solution Overview
Problem
Conventional power management systems for back-up batteries struggle to maintain full capacity and deliver peak current to critical loads, such as data buses, during cold ambient temperatures due to high internal resistance and aging issues, leading to insufficient heating by battery chargers, resulting in prolonged downtime of critical loads.
Innovation Solution
A power management system that utilizes both low and high power heaters, with the battery charger powering the low power heater during maintenance mode and both heaters during boost mode, supplemented by residual battery power to rapidly reach the desired operating temperature, ensuring the batteries can supply required capacity and current to critical loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the battery charger powers the heater during cold ambient temperatures, then the battery temperature increases to enable full capacity delivery, but the heating time becomes excessively long due to insufficient charger capacity
Solution Approach 1:
The system dynamically switches between two operating modes: a first mode where the battery charger alone powers the heater, and a second mode where both the battery charger and the battery simultaneously power the heater. This dynamic adaptation allows the system to provide sufficient heating power during critical cold temperature conditions, dramatically reducing heating time while maintaining battery temperature within operational ranges.
Solution Approach 2:
The control circuit monitors battery temperature and charging state, then adjusts the heating power parameters accordingly. When the battery temperature drops below a threshold or during high-current discharge modes, the system increases heating power by engaging the battery itself as a power source, thereby changing the operational parameters to achieve faster heating without compromising battery safety.
2Speed
If the battery provides residual power to boost heater capacity, then the heating speed increases to reach operating temperature quickly, but the battery charge depletes faster
Solution Approach 1:
The system maintains continuous heating action by coordinating the battery charger and battery power sources. The heater remains actively powered during charging phases to prevent temperature drop, and during discharge phases to enable fast heating when needed. This continuous useful action ensures the battery stays within operational temperature ranges while minimizing unnecessary energy depletion.
Solution Approach 2:
The control circuit continuously monitors battery temperature, charge state, and discharge current, then provides feedback to adjust heating power accordingly. When the battery is in a high state of charge and temperature is adequate, heating power is reduced or suspended. When temperature drops or high current discharge is detected, heating power is increased by engaging the battery as a power source, creating a closed-loop control system that optimizes energy usage.
3Reliability
If the battery is heated to full operating temperature before power loss, then the battery can deliver full capacity during backup, but the internal resistance remains high during cold ambient conditions preventing full capacity delivery
Solution Approach 1:
The system applies preliminary heating action through the dedicated heater element before the battery is required to deliver full capacity. By actively heating the battery during charging phases and when ambient conditions are cold, the system counteracts the natural tendency of internal resistance to increase at low temperatures, ensuring the battery maintains low internal resistance and full capacity delivery capability when needed.
Solution Approach 2:
The battery charger is configured to simultaneously charge the battery and power the heater during cold ambient conditions, performing preliminary heating action in advance of any potential power loss event. This preliminary action ensures the battery reaches optimal operating temperature and maintains low internal resistance, preparing the battery to deliver full capacity immediately upon power loss without waiting for gradual warming.
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 enables back-up batteries to quickly reach operating temperature and maintain capacity, minimizing downtime of critical loads by leveraging residual battery power to accelerate heating, thus ensuring reliable power supply during primary power loss and restoration.
Implementation Method 1
the battery charger selectively activates the heater to heat the battery
Data Source
AI summary
The invention relates to a power management system for supplying backup DC power to peak and/or high current demand battery applications, such as motor starting or an uninterruptible power supply (UPS) used to power a critical load, such as, a data bus or other critical load, after an event, such as loss of primary AC or DC input, during relatively cold ambient temperatures. Two or more heaters can be provided; for example, a low power heater and a high-power heater. In a maintenance mode, the low power heater is used to maintain batteries at a predetermined temperature. In this mode, a battery charger is used to power the low power heater. In a boost mode, after the primary AC or DC input is restored, and battery temperature is too low to back up the critical load, the battery charger supplies power to one or both of the heaters. Since capacity of the battery charger is normally insufficient to heat the batteries to an acceptable operating temperature in a relatively short period of time, a portion of residual power from the batteries is used to boost power to the heaters in order to speed up the time to get each battery of said batteries to its rated operating temperature.