Vehicle Jump-Start Relay Control for Battery Protection
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Solution Overview
Problem
Conventional methods for jump-starting vehicles risk damaging auxiliary batteries and relays due to overcurrent or overvoltage from external power supplies, and lack stable control over the electrical system, potentially leading to vehicle shutdowns.
Innovation Solution
A vehicle power control method and system utilizing a low voltage DC/DC converter, relays, and a controller to manage the electrical connections and current limitations, ensuring the auxiliary battery and relay are protected from overcurrent, and maintaining power output to prevent vehicle shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an external power supply is connected to charge a discharged auxiliary battery for jump-start, then the vehicle can be started, but the auxiliary battery may be damaged by overcurrent or overvoltage from the external power supply
Solution Approach 1:
The patent introduces a control system with relays as intermediary components between the external power supply and the auxiliary battery. The first relay controls connection to the auxiliary battery while the second relay controls connection to the jump-start terminal, acting as mediators that prevent direct overcurrent damage. The control unit coordinates these relays to ensure safe charging operations.
Solution Approach 2:
The control unit performs preliminary assessment of the auxiliary battery's state of charge before enabling jump-start operation. The system checks battery voltage and determines appropriate charging parameters in advance, preventing overcurrent damage by establishing safe operating conditions before the external power supply is connected.
2Reliability
If the relay that sets the electrical connection of the auxiliary battery is turned off to protect the battery, then the battery is protected from overcurrent, but the vehicle may not be able to start or may shut down
Solution Approach 1:
The patent segments the electrical connection control into two independent relay systems: the first relay controls the auxiliary battery connection, and the second relay controls the jump-start terminal connection. This segmentation allows the battery to be protected (first relay off) while still enabling jump-start functionality (second relay on), resolving the contradiction between protection and operability.
Solution Approach 2:
The control unit acts as an intermediary that coordinates the two relays, ensuring that when the first relay is turned off to protect the battery, the second relay is turned on to maintain vehicle starting capability through the jump-start terminal. The control unit mediates between protection requirements and operational requirements.
3Reliability
If current is limited to protect the auxiliary battery after jump-start, then overcharge damage is prevented, but the power output may be insufficient for vehicle operation
Solution Approach 1:
The control unit dynamically adjusts the charging current based on real-time monitoring of the auxiliary battery's state of charge. The current limitation is not fixed but adapts during the charging process, allowing higher current when the battery needs charging and reducing current as the battery approaches full charge, thus balancing protection with power availability.
Solution Approach 2:
The system changes the current parameter dynamically during the jump-start and charging process. The control unit monitors battery voltage and adjusts the charging current threshold accordingly, allowing sufficient power output during critical phases while preventing overcharge damage when the battery is nearly full.
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
Prevents damage to auxiliary batteries and relays from overcurrent, ensures stable vehicle operation during jump-start, and prevents overcharge currents, thereby maintaining the vehicle's power supply and preventing shutdowns.
Implementation Method 1
a low voltage DC/DC converter for converting a voltage of a high voltage battery into a low voltage to be output
Implementation Method 2
a first relay, which is connected between an auxiliary battery and an output terminal of a low voltage DC/DC converter and determines an electrical connection state between the auxiliary battery and the output terminal of the low voltage DC/DC converter
Data Source
AI summary
A vehicle power control method for jump-start uses a vehicle control system that includes a low voltage DC/DC converter for converting a voltage of a high voltage battery to a low voltage to be output and a junction box for connecting the low voltage DC/DC converter to an auxiliary battery and load. The vehicle power control method includes a jump-start preparation step in which when the auxiliary battery is in a discharge condition, a first relay, which connects or disconnects the junction box to or from the auxiliary battery, is turned off and a second relay, which connects or disconnects the junction box to or from a jump-start power supply connection terminal, is turned on; and a jump-start completion step in which, after a vehicle starts by a power inputted through the jump-start power supply connection terminal, the second relay is turned off, and the first relay is turned on.