TECHNICAL FIELD

THIS APPLICATION claims priority to and the benefit of Korean Patent Application No. 10-2017-0044680 filed in the Korean Intellectual Property Office on Apr. 6, 2017, the entire contents of which are incorporated herein by reference.

The present invention relates to a system and a method of diagnosing a state of a low-voltage battery, and more particularly, to a system and a method of diagnosing a state of a low-voltage battery, in which, in order to diagnose a state of a low-voltage battery (12V aux battery) provided at a low-voltage side, a daisy chain circuit unit receives a voltage from the low-voltage battery and outputs one or more result signals, and an isolator unit, which electrically insulates a high-voltage side and the low-voltage side, converts the one or more result signals output from the daisy chain circuit unit and provides the converted signals to a control unit, thereby diagnosing a state of the low-voltage battery at the low-voltage side by using the control unit provided at the high-voltage side without additionally providing a control unit at the low-voltage side.

BACKGROUND ART

In general, a battery management system (BMS) developed and produced for managing a battery measures a voltage of a high-voltage battery provided at a high-voltage side and diagnoses and manages a voltage state of the battery based on the measured voltage through a control unit, such as a micro controller unit (MCU). However, since the control unit, such as the MCU, is not provided at a low-voltage side, there is a problem in that it is impossible to diagnose a voltage state of a low-voltage battery (12 V aux battery) provided at the low-voltage side.

In order to solve the problem, in order to diagnose a voltage state of a low-voltage battery, a BMS in the related art uses a scheme of distributing a voltage of a low-voltage battery by resistance distribution, applying the distributed voltage to an MCU located at a low-voltage side, and diagnosing a voltage state of the low-voltage battery.

In the meantime, in the scheme of diagnosing a state of a low-voltage battery in the related art, a constituent element serving as an additional control unit needs to be provided at the low-voltage side, in addition to the control unit provided at the high-voltage side, so that there is a problem in that manufacturing cost and volume of an entire system are increased to degrade entire efficiency of the BMS.

In this respect, in order to solve the problems of a system and a method of diagnosing a state of a low-voltage battery in the related art, the present inventors invented a system and a method of diagnosing a state of a low-voltage battery, in which, in order to diagnose a state of a low-voltage battery provided at a low-voltage side, a daisy chain circuit unit receives a voltage from the low-voltage battery and outputs one or more result signals, and an isolator unit, which electrically insulates a high-voltage side and the low-voltage side, converts the one or more result signals output from the daisy chain circuit unit and provides the converted signals to a control unit, thereby diagnosing a state of the low-voltage battery at the low-voltage side by using the control unit provided at the high-voltage side without additionally providing a control unit at the low-voltage side.

DETAILED DESCRIPTION OF THE INVENTION

Technical Problem

The present invention is conceived to solve the problems, and provides a system and a method of diagnosing a state of a low-voltage battery, in which, in order to diagnose a state of a low-voltage battery (12V aux battery) provided at a low-voltage side, a daisy chain circuit unit receives a voltage from the low-voltage battery and outputs one or more result signals, and an isolator unit, which electrically insulates a high-voltage side and the low-voltage side, converts the one or more result signals output from the daisy chain circuit unit and provides the converted signals to a control unit, thereby diagnosing a state of the low-voltage battery at the low-voltage side by using the control unit provided at the high-voltage side without additionally providing a control unit at the low-voltage side.

Technical Solution

An exemplary embodiment of the present invention provides a system for diagnosing a state of a low-voltage battery, the system including: a daisy chain circuit unit configured to receive a voltage from a low-voltage battery, and output one or more result signals based on the received voltage and a first reference voltage; an isolator unit configured to receive the one or more output result signals, and convert the one or more received result signals; and a control unit configured to receive the one or more converted result signals and diagnose the state of the low-voltage battery, in which the daisy chain circuit unit is provided at a low-voltage side including the low-voltage battery, and the control unit is provided at a high-voltage side including a high-voltage battery.

In the exemplary embodiment, the isolator unit may be located between the daisy chain circuit unit and the control unit, and insulates and electrically isolate the daisy chain circuit unit and the control unit.

In the exemplary embodiment, the daisy chain circuit unit may include a reference voltage setting unit configured to set the first reference voltage, and adjust a size of the first reference voltage based on one or more of a size and kind of signal input to the daisy chain circuit unit.

In the exemplary embodiment, the isolator unit may include: a coupler unit configured to convert the one or more received result signals; and a Schmitt trigger circuit unit configured to compare the one or more converted result signals with a second reference voltage and output one or more comparison result signals.

In the exemplary embodiment, the Schmitt trigger circuit unit may further be configured to adjust a size of the second reference voltage according to a size and a kind of signal input to the Schmitt trigger circuit unit.

In the exemplary embodiment, the daisy chain circuit unit may further be configured to output the one or more result signals based on a voltage signal of the low-voltage battery, and output one or more of an input voltage signal of the daisy chain circuit unit and a feedback signal of an output voltage of the daisy chain circuit unit.

In the exemplary embodiment, the daisy chain circuit unit may be connected with one or more cell module controllers (CMCs), each CMC being connected with a respective battery module, the one or more CMCs are connected to the control unit by a daisy chain connection scheme, and the daisy chain circuit unit may check disconnection between the one or more CMCs, the control unit, and the daisy chain circuit unit based on the one or more result signals.

Another exemplary embodiment of the present invention provides a method of diagnosing a state of a low-voltage battery, the method including: providing a daisy chain circuit unit at a low-voltage side including the low-voltage battery; providing a control unit at a high-voltage side including a high-voltage battery; receiving, by the daisy chain circuit unit, a voltage from the low-voltage battery, and outputting one or more result signals based on the received voltage and a first reference voltage; receiving, by an isolator unit, the one or more output result signals, and converting the one or more received result signals; and receiving, by the control unit, the one or more converted result signals and diagnosing a state of the low-voltage battery.

In the exemplary embodiment, the converting of the one or more result signals may include insulating and electrically isolating, by the isolator unit, the low-voltage battery, the daisy chain circuit unit, and the control unit, the isolator unit being located between the low-voltage battery and control unit, and between the daisy chain circuit, unit and the control unit.

In the exemplary embodiment, the outputting of the one or more result signals may include setting, by a reference voltage setting unit, the first reference voltage, and the setting of the first reference voltage may include adjusting a size of the first reference voltage based on one or more of a size and a kind of signal input to the daisy chain circuit unit.

In the exemplary embodiment, the outputting of the one or more result signals may include: converting, by a coupler unit, the one or more received result signals; and comparing, by a Schmitt trigger circuit unit, the one or more converted result signals with a second reference voltage and outputting one or more comparison result signals.

In the exemplary embodiment, the outputting of the one or more comparison result signals may include adjusting a size of the second reference voltage according to a size and a kind of signal input to the Schmitt trigger circuit unit.

In the exemplary embodiment, the outputting of the one or more result signals may include outputting the one or more result signals based on a voltage signal of the low-voltage battery, and one or more of an input voltage signal of the daisy chain circuit unit and a feedback signal of an output voltage of the daisy chain circuit unit.

In the exemplary embodiment, the method may further include connecting the daisy chain circuit unit with one or more cell module controllers (CMCs), each CMC being connected with a respective battery module, the one or more CMCs are connected to the control unit by a daisy chain connection scheme, in which the outputting of the one or more result signals may include checking disconnection between the one or more CMCs, the control unit, and the daisy chain circuit unit based on the one or more result signals.

Advantageous Effect

According to the present invention, in order to diagnose a state of a low-voltage battery (12V aux battery) provided at a low-voltage side, a daisy chain circuit unit receives a voltage from the low-voltage battery and outputs one or more result signals, and an isolator unit, which electrically insulates a high-voltage side and the low-voltage side, converts the one or more result signals output from the daisy chain circuit unit and provides the converted signals to a control unit, so that it is possible to diagnose a state of the low-voltage battery at the low-voltage side by using the control unit provided at the high-voltage side without additionally providing a control unit at the low-voltage side, and there is no need for a control unit for diagnosing a state of the low-voltage battery at the low-voltage side, thereby decreasing cost and a volume of the system.

Further, the present invention receives feedback signals of an input voltage and an output voltage of the daisy chain circuit unit and sets a reference voltage based on the kind and a size of the received signal, so that it is possible to diagnose an input/output state of the daisy chain circuit unit provided at the low-voltage side, as well as a voltage of the low-voltage battery, and even when the input signal is changed, it is possible to receive various signals and diagnose a state of the low-voltage battery because a unique characteristic of the present invention is not changed.

