Bidirectional DC-DC Converter Battery Self-Heating Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing temperature control methods for electricity storage devices, such as lithium-ion batteries, face challenges in efficiently increasing battery temperature at low temperatures, leading to reduced charging and discharging capacities, and consume unnecessary electricity when trying to warm up the battery.
Innovation Solution
A temperature control apparatus and method using a bidirectional DC-DC converter to manage charging and discharging between multiple electricity storage devices, allowing for precise temperature control by calculating and adjusting the conduction ratio based on internal resistance and state of charge, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a refrigerant circuit is used to warm up the battery neighborhood, then the battery temperature can be maintained at preset temperature, but the response time is slow and power consumption increases
Solution Approach 1:
The battery warms itself up by performing forced charging or discharging operations. The internal resistance of the battery generates heat through its own electrical operations, eliminating the need for external heating systems like refrigerant circuits. This self-heating mechanism provides rapid temperature increase while the controller manages the charging/discharging cycles to achieve the desired temperature.
2Temperature
If forced charging or discharging is performed to warm up the battery, then the battery temperature increases rapidly, but electricity is consumed in vain when load is applied
Solution Approach 1:
The controller continuously monitors the battery temperature and adjusts the charging/discharging operations accordingly. When the battery temperature reaches the preset value, the controller stops the forced charging/discharging operations, preventing unnecessary power consumption. This feedback control mechanism ensures that heating operations are performed only when needed and stopped when the target temperature is achieved.
3Temperature
If forced charging or discharging is performed to warm up the battery, then the battery temperature increases rapidly, but electricity stored in the battery is consumed
Solution Approach 1:
The controller performs periodic charging and discharging operations to generate heat through internal resistance. By alternating between charging and discharging cycles, the system can warm the battery without depleting its overall energy storage, as the energy is cycled through the battery to generate heat rather than being consumed for external work.
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 approach enables rapid and efficient temperature increase of electricity storage devices without consuming excess electricity, significantly reducing power consumption compared to prior methods.
Implementation Method 1
a bidirectional DC-DC converter, so that the first electricity storage device is connected in parallel to the second electricity storage device through the bidirectional DC-DC converter and a DC link
Implementation Method 2
heat generating as a result of the charging or discharging is used to control a temperature of the battery so as to become a preset temperature. When a temperature of the battery is lower than the preset temperature, charging or discharging is forcibly performed to feed current to the battery, and this leads to generation of heat from the internal resistance of the battery
Data Source
AI summary
In a power storage system, a bidirectional DC-DC converter is set into mode for charging a secondary battery with electricity when a first state of charge (SOC) of the secondary battery is larger than a minimum value of the first SOC, and a second SOC of the capacitor is smaller than a maximum value of the second SOC, and the converter is set into mode for discharging electricity from the secondary battery when the first SOC is smaller than a maximum value of the first SOC, and the second SOC is larger than a minimum value of the second SOC. Based on an internal resistance of the secondary battery, the second SOC, a voltage of a direct current link in case of no load connected to DC link, and an error in a current on a direct current link side, a conduction ratio (D) of the converter is calculated.