Battery Heating Device Using LC Resonance Current Ripple
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Solution Overview
Problem
Existing battery heating techniques, such as those described in JP 2012-210138 A, have limitations in effectively raising battery temperature due to a constant and limited current ripple amplitude, necessitating an improvement in battery heating devices to enhance temperature elevation.
Innovation Solution
A battery heating device comprising a capacitor and a reactor connected in parallel between a battery and a load, with a controller managing the ON/OFF states of switches to control the reactor current, allowing for increased ripple amplitude through LC resonance, effectively raising the battery temperature by alternating the switching states of the switching elements based on current direction and value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a current ripple generated with a switching operation of a switching element is used to raise battery temperature, then the battery temperature can be increased, but the amplitude of the current ripple is constant and limited, resulting in insufficient heating effect
Solution Approach 1:
The patent applies dynamics by making the switching element's ON/OFF timing variable rather than fixed. The control unit adjusts the ON/OFF timing based on detected reactor current values to maximize current ripple amplitude. This dynamic adjustment allows the system to optimize heating effect at different operating conditions, resolving the contradiction between maintaining constant operation and achieving maximum heating power.
Solution Approach 2:
The patent changes the parameter of switching timing to optimize current ripple characteristics. By varying the ON/OFF timing of the switching element according to detected current values, the system modifies the electrical parameters to achieve maximum ripple amplitude. This parameter change enables the system to overcome the limitation of constant ripple amplitude and achieve effective battery heating.
2Temperature
If the switching element is operated to generate current ripple for heating, then battery temperature rises, but additional heating components are required which increases device complexity
Solution Approach 1:
The patent applies universality by enabling the existing switching element to perform dual functions: voltage conversion and battery heating. The switching element that is already part of the voltage converter circuit is controlled to generate current ripple for heating purposes. This eliminates the need for separate heating components, reducing device complexity while achieving effective battery temperature control.
Solution Approach 2:
The patent implements self-service by using the voltage converter's own switching element to provide heating function. The system utilizes its existing components to serve the heating need, rather than requiring external or additional heating devices. This self-service approach simplifies the overall system structure while maintaining effective heating capability.
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
The solution effectively increases the amplitude of the reactor current, allowing for efficient battery temperature elevation, even at low temperatures, without the need for additional heating components, thereby improving battery performance and readiness for vehicle operation.
Implementation Method 1
A battery heating device according to an exemplary embodiment may increase an amplitude of a ripple current, and effectively raise a temperature of the battery. That is, a structure of a voltage converter may be used for heating, and thus, it is not necessary to provide a heater or the like for raising a battery temperature.
Data Source
AI summary
A battery heating device includes: a capacitor connected in parallel between a battery and a load; a reactor connected to the capacitor; a first switch connected to a terminal on the load side of the reactor, and to one terminal of the capacitor; a second switch connected to a terminal on the load side of the reactor, and to another terminal of the capacitor; a controller configured to control an ON/OFF state of the first switch and the second switch; and a current sensor configured to detect a direction and a current value of a reactor current flowing in the reactor. The controller performs battery heating mode control including a first control of turning OFF the first switch and turning ON the second switch when a current value becomes substantially zero from a state where the reactor current flows from the load side to the battery side.