Patent Description:
A conventional mechanical relay is connected between a battery for an electric vehicle and an external device, to control electrical connection between the battery and the external device. However, since the mechanical relay has a large volume and high power consumption, a technique for replacing the mechanical relay with an electronic switch has been studied.

In the case of a low-voltage battery, since a load applied to an electronic switch is small, the electronic switch may be easily applied instead of a mechanical relay. For example, a plurality of switches are connected in series and in parallel and used in consideration of limits of an allowable current and voltage that can flow through a switch element and ease of controlling heat of the switch element. In this case, there is a problem in that it is impossible to determine whether each of the switches connected in series and parallel has a failure.

A voltage or current sensor must be provided at opposite ends of each switch to determine whether a failure occurs in an on or off state for each switch, which causes problems such as an increase in cost, an increase in circuit complexity, and an increase in printed circuit board (PCB) area.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. <CIT> relates to an electronic control device serially provided with a first switch and a second switch of a relay and an FET between an electronic control part and an auxiliary electric power source that determines that both of the switches do not short when voltage V2 in putting off both of the switches is lower than a specified value. The device also determines that the first switch does not open-fail when V1 and V2 are almost equal when the first switch is put on and the second switch is put off and determines that the second switch does not open-fail when both of the switches are reversely put on and off and V2 and V3 are roughly equal, and consequently, it is possible to almost eliminate the voltage lowering by both of the switches to determine failure of both of the switches.

The present disclosure has been made in an effort to provide an error detecting method of a charging switch unit and a battery system to which the same is applied.

An embodiment of the present invention provides an error detecting method according to claim <NUM>.

The error detecting method of the charging switch unit may further include opening the second charging switch in response to the first charging switch being switched to open and the voltages at the opposite ends of the second charging switches being within the predetermined range.

The error detecting method of the charging switch unit may further include closing the second charging switch in response to the first charging switch being switched to closed, and the voltages at the opposite ends of the first charging switch being within the predetermined range.

The error detecting method of the charging switch unit may further include: switching the second charging according to the switch control command; and in response to the second charging switch being switched to open determining whether the voltages at the opposite ends of the first charging switch are within the predetermined range ; and determining that the second charging switch is normal in response to the voltages at the opposite ends of the first charging switch being within the predetermined range.

The error detecting method of the charging switch unit may further include opening the first charging switch in response to the second charging switch being switched to open, and the voltages at the opposite ends of the first charging switch being within the predetermined range.

The error detecting method of the charging switch unit may further include: switching the second charging according to the switch control command; and in response to the second charging switch being switched to open determining whether the voltages at the opposite ends of the second charging switch are within the predetermined range ; and determining that the second charging switch is normal in response to the voltages at the opposite ends of the second charging switch being within the predetermined range.

The error detecting method of the charging switch unit may further include closing the first charging switch in response to the second charging switch being switched to closed, and the voltages at the opposite ends of the second charging switch being within the predetermined range.

The error detecting method of the charging switch unit may further include determining which of the first charging switch and the second charging switch to switch according to the switch control command based on the switch control command.

Another embodiment of the present invention provides a battery system according to claim <NUM>.

The battery management system may include a main control circuit configured to generate a first charging control signal that controls a switching operation of the first charging switch, and generate a second charging control signal that switches the second charging switch in response to the first charging switch being normal.

The main control circuit may be configured to generate the first charging control signal at a disable level in response to the switch control command indicating to open the first charging switch and generate the second charging control signal at the disable level in response to the voltage of the intermediate location and the voltage of the second terminal being within the predetermined range.

The main control circuit may be configured to generate the first charging control signal at an enable level in response to the switch control command indicating to close the first charging switch and generate the second charging control signal at the enable level in response to the voltage of the intermediate location and the voltage of the first terminal being within the predetermined range.

The battery management system may be configured to in response to a switch control command indicating to open the second charging switch before the first charging switch, determine whether the second charging switch is normal based on the voltage of the intermediate location and a voltage of the first terminal being within the predetermined range; and
in response to the switch control command indicating to close the second charging switch before the first charging switch, determine whether the second switch is normal based on the voltage of the second terminal and the voltage of the intermediate location being within the predetermined range.

The battery management system may include a main control circuit configured to generate a second charging control signal that controls a switching operation of the second charging switch, and to generate a first charging control signal that switches the first charging switch in response to the second charging switch being normal.

The main control circuit may be configured to generate the second charging control signal at a disable level in response to the switch control command indicating to open the second charging switch, and generate the first charging control signal at the disable level in response to the voltage of the intermediate location and the voltage of the first terminal being within the predetermined range.

The main control circuit may be configured to generate the second charging control signal at an enable level in response to the switch control command indicating to close the first charging switch, and generate the first charging control signal at the enable level in response to the voltage of the intermediate location and the voltage of the second terminal being within the predetermined range.

The present disclosure provides a method for detecting an error in a charging switch unit without an increase in cost, an increase in circuit complexity, and an increase in PCB area, and a battery system to which the same is applied.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings. In the present specification, the same or similar components will be denoted by the same or similar reference numerals, and a repeated description thereof will be omitted. Terms "module" and/or "unit" for components used in the following description are used only in order to easily describe the specification. Therefore, these terms do not have meanings or roles that distinguish them from each other in and of themselves. In describing embodiments of the present specification, when it is determined that a detailed description of the well-known art associated with the present invention may obscure the gist of the present invention, it will be omitted. The accompanying drawings are provided only in order to allow embodiments disclosed in the present specification to be easily understood and are not to be interpreted as limiting the spirit disclosed in the present specification, and it is to be understood that the present invention is defined by the appended claims.

Terms including ordinal numbers such as first, second, and the like will be used only to describe various components, and are not to be interpreted as limiting these components. The terms are only used to differentiate one component from other components.

It is to be understood that when one component is referred to as being "connected" or "coupled" to another component, it may be connected or coupled directly to the other component or be connected or coupled to the other component with a further component intervening therebetween. On the other hand, it is to be understood that when one component is referred to as being "connected or coupled directly" to another component, it may be connected to or coupled to the other component without another component intervening therebetween.

It will be further understood that terms "comprises/includes" or "have" used in the present specification specify the presence of stated features, numerals, steps, operations, components, parts, or a combination thereof, but do not preclude the presence or addition of one or more other features, numerals, steps, operations, components, parts, or a combination thereof.

<FIG> illustrates a battery system according to an embodiment.

In <FIG>, the battery system <NUM> is connected to a charger <NUM> through a charging line <NUM> and to a load <NUM> through a discharging line <NUM>.

The battery system <NUM> includes a battery module <NUM>, a battery management system (BMS) <NUM>, a charging switch unit <NUM>, and a discharging switch unit <NUM>.

In <FIG>, the battery module <NUM> is illustrated as having n battery cells C1 to Cn connected in series, but the present invention is not limited thereto. A number of battery cells constituting the battery module <NUM> may be set to an appropriate number for supplying power to a load. In addition, the battery module <NUM> may be configured by serially connecting battery packs in which a plurality of battery cells are connected in series, or by connecting battery packs in parallel. That is, the number and connection relationship of each of the battery packs and battery cells constituting the battery module may be appropriately designed to supply necessary power.

The BMS <NUM> senses battery cell information for each of the battery cells C1 to Cn, manages an operation of the battery module <NUM> based on the sensed battery cell information, and controls switching of the charging switch unit <NUM> and the discharging switch unit <NUM>. In addition, the BMS <NUM> may diagnose the charging switch unit <NUM> to determine whether there is an error.

The BMS <NUM> includes a cell monitoring IC <NUM>, a main control circuit <NUM>, and a switch diagnosis unit <NUM>.

The cell monitoring IC <NUM> may be electrically connected to the battery cells C1 to Cn to sense battery cell information for each of the battery cells C1 to Cn, and may transfer the sensed battery cell information to the main control circuit <NUM>. The battery cell information may include a voltage, a temperature, and the like of a battery cell.

The main control circuit <NUM> receives a signal regarding battery cell information of each of the battery cells from the cell monitoring IC <NUM> and signals instructing charging and discharging from an electronic control circuit of a vehicle to which the battery system <NUM> is applied, to manages the battery module <NUM> and control the switching of the charging switch unit <NUM> and the discharging switch unit <NUM> based on the received signals. Management of the battery module <NUM> includes an overvoltage and overcurrent protection operation for the battery module <NUM>, a cell balancing operation for the battery cells C1 to Cn, charging and discharging of the battery module <NUM>, and the like.

The main control circuit <NUM> may measure a voltage of the battery module <NUM> during charging or a voltage of the battery module <NUM> during discharging through the charging line <NUM> or the discharging line <NUM>. In addition, information related to a sensed current may be received from a current sensor (not illustrated) that senses a current flowing through the battery module <NUM>.

The main control circuit <NUM> may generate battery cell information, a state of charge (SOC), a health state, etc. of each of the battery cells, and may construct the generated information as battery state signals to transmit them to an electronic control circuit of a vehicle through CAN communication.

The switch diagnosis unit <NUM> may measure a voltage of each of an input terminal N1, an intermediate terminal N3, and an output terminal N2 of the charging switch unit <NUM>, and may diagnose the charging switch unit <NUM> based on a measurement result thereof to determine whether there is an error. The input terminal N1 is a node to which the charger <NUM> and the charging switch unit <NUM> are connected, the intermediate terminal N3 is a node to which a first charging switch <NUM> and a second charging switch <NUM> are connected, and the output terminal N2 is a node to which the charging switch unit <NUM> and the battery module <NUM> are connected. The switch diagnosis unit <NUM>, the charging switch unit <NUM>, and the discharging switch unit <NUM> will be described later with reference to <FIG> together with <FIG>.

The load <NUM> may be an electric load of the vehicle to which the battery system <NUM> is applied. The content shown in <FIG> is an example for describing the present invention, and the present invention is not limited thereto. When the discharging switch unit <NUM> is turned on, the battery module <NUM> and the load <NUM> are connected, and power is supplied from the battery module <NUM> to the load <NUM>.

The charger <NUM> may be implemented as a DC-DC converter, and converts input power to generate output power of a voltage that is suitable for charging the battery module <NUM>. When the charging switch unit <NUM> is turned on, the charger <NUM> may be connected to the battery module <NUM> through the charging line <NUM>, and power may be supplied to the battery module <NUM> from the charger <NUM>.

The charging switch unit <NUM> may be electrically connected to each of the charger <NUM> and the battery module <NUM> through the charging line <NUM>. The charging switch unit <NUM> includes a first charging switch <NUM>, a second charging switch <NUM>, and two gate drivers <NUM> and <NUM>. The gate driver <NUM> and the gate driver <NUM> respectively generate gate voltages VG1 and VG2 that control switching of the first charging switch <NUM> and the second charging switch <NUM> depending on a first charging control signal CHS1 and a second charging control signal CHS2 transmitted from the BMS <NUM>.

The discharging switch unit <NUM> is electrically connected to each of the battery module <NUM> and the load <NUM> through a discharging line <NUM>. The discharging switch unit <NUM> includes a discharging switch <NUM> and a gate driver <NUM>. The gate driver <NUM> generates a gate voltage VG3 that controls switching of the discharging switch <NUM> depending on a discharging control signal DCHS transmitted from the BMS <NUM>.

<FIG> illustrates a circuit diagram specifically showing a charging switch unit and a discharging switch unit according to an embodiment.

As illustrated in <FIG>, the charging switch unit <NUM> includes a first charging switch <NUM> and a second charging switch <NUM> connected in series and gate drivers <NUM> and <NUM>, the first charging switch <NUM> includes three switches <NUM> to <NUM> connected in parallel, and the second charging switch <NUM> includes three switches <NUM> to <NUM> connected in parallel. A number of switches constituting the first charging switch <NUM> and the second charging switch <NUM> may be determined depending on a magnitude of the current flowing in the charging line <NUM>, and three switches are illustrated in <FIG> as an example for describing an embodiment, and the present invention is not limited thereto.

In addition, although the switches <NUM> to <NUM> and <NUM> to <NUM> are illustrated as n-channel MOSFETs in <FIG>, a channel type of the transistor and a type of the transistor are not limited thereto. Hereinafter, in the description of <FIG>, each of opposite ends of the MOSFET is divided into a first end or a second end instead of a source and a drain.

The three switches <NUM> to <NUM> are connected between the input terminal N1 and the intermediate terminal N3, a first end of each of the three switches <NUM> to <NUM> is connected to the input terminal N1, and a second end is connected to the intermediate terminal N3. A gate voltage VG1 outputted from the gate driver <NUM> is applied to gates of the three switches <NUM> to <NUM>.

The three switches <NUM> to <NUM> are connected between the output N2 and the intermediate terminal N3, a first end of each of the three switches <NUM> to <NUM> is connected to the output N2, and a second end is connected to the intermediate terminal N3. A gate voltage VG2 outputted from the gate driver <NUM> is applied to gates of the three switches <NUM> to <NUM>.

The gate driver <NUM> generates the gate voltage VG1 depending on the first charging control signal CHS1 transmitted from the main control circuit <NUM>. For example, the gate driver <NUM> may generate the gate voltage VG1 of an on level depending on the first charging control signal CHS1 of a level (enable level) instructing turn-on of the first charging switch <NUM>. The gate driver <NUM> may generate the gate voltage VG1 of an off level depending on the first charging control signal CHS1 of a level (disable level) instructing turn-off of the first charging switch <NUM>. Since the three switches <NUM> to <NUM> constituting the first charging switch <NUM> are of an n-channel type, the on level may be a high level and the off level may be a low level.

The gate driver <NUM> generates the gate voltage VG2 depending on the second charging control signal CHS2 transmitted from the main control circuit <NUM>. For example, the gate driver <NUM> may generate the gate voltage VG2 of an on level depending on the second charging control signal CHS2 of a level (enable level) instructing turn-on of the second charging switch <NUM>. The gate driver <NUM> may generate the gate voltage VG2 of an off level depending on the second charging control signal CHS2 of a level (disable level) instructing turn-off of the second charging switch <NUM>. Since the three switches <NUM> to <NUM> constituting the second charging switch <NUM> are of an n-channel type, the on level may be a high level and the off level may be a low level.

For charging, when the charging switch unit <NUM> is turned on, the first charging control signal CHS1 and the second charging control signal CHS2 may be synchronized to the enable level at a same time point. During diagnosis for detecting an error in the charging switch unit <NUM>, a time difference may exist between time points at which the first charging control signal CHS1 and the second charging control signal CHS2 are respectively enabled. This will be described with reference to <FIG>.

As illustrated in <FIG>, the discharging switch unit <NUM> includes a discharging switch <NUM> and a gate driver <NUM>, and the discharging switch <NUM> includes two discharging switches <NUM> and <NUM> connected in parallel. A number of switches constituting the discharging switch <NUM> may be determined depending on a magnitude of the current flowing in the discharging line <NUM>, and two switches are illustrated in <FIG> as an example for describing an embodiment, and the present invention is not limited thereto.

In addition, although the switches <NUM> and <NUM> are illustrated as n-channel MOSFETs in <FIG>, a channel type of the transistor and a type of the transistor are not limited thereto.

The two switches <NUM> and <NUM> are connected between the output N2 and the load <NUM>, a first end of each of the two switches <NUM> and <NUM> is connected to the output N2, and a second end is connected to the load N3. A gate voltage VG3 outputted from the gate driver <NUM> is applied to gates of the two switches <NUM> and <NUM>.

The gate driver <NUM> generates the gate voltage VG3 depending on the discharging control signal DCHS transmitted from the main control circuit <NUM>. For example, the gate driver <NUM> may generate the gate voltage VG3 of an on level depending on the discharging control signal DCHS of a level (enable level) instructing turn-on of the discharging switch <NUM>. The gate driver <NUM> may generate the gate voltage VG3 of an off level depending on the discharging control signal DCHS of a level (disable level) instructing turn-off of the discharging switch <NUM>. Since the two switches <NUM> and <NUM> constituting the discharging switch <NUM> are of an n-channel type, the on level may be a high level and the off level may be a low level.

<FIG> illustrates voltages of an input terminal, an intermediate terminal, and an output terminal of a charging switch unit depending on states of a first charging switch and a second charging switch in a normal state.

As illustrated in <FIG>, when the first charging switch <NUM> is opened and the second charging switch <NUM> is closed, a voltage VN1 of the input terminal N1 is a voltage VS of a power supplied from the charger <NUM>, and a voltage VN3 and a voltage VN2 of the intermediate terminal N3 and the output terminal N2 are similar. It is said to be similar when a difference between the two voltages VN3 and VN2 is within a predetermined range, and the predetermined range may be a voltage obtained by adding a predetermined margin to a voltage at opposite ends when the second charging switch <NUM> is closed.

When the first charging switch <NUM> is closed and the second charging switch <NUM> is opened, the voltage VN2 of the output terminal N2 is the voltage VB of the battery module <NUM> and is the voltage of the power supplied from the charger <NUM>, and the voltage VN3 of the intermediate terminal N3 and the voltage VN1 of the input terminal N1 are similar. It is said to be similar when a difference between the two voltages VN3 and VN1 is within a predetermined range, and the predetermined range may be a voltage obtained by adding a predetermined margin to a voltage at opposite ends when the first charging switch <NUM> is closed.

When the first charging switch is closed and the second charging switch is closed, the voltage VN1, the voltage VN2, and the voltage VN3 of the input terminal N1, the intermediate terminal N3, and the output terminal N2 are all within a predetermined range and are similar to each other.

Even when the first charging switch <NUM> is opened and the second charging switch <NUM> is opened, the voltage VN1, the voltage VN2, and the voltage VN3 of the input terminal N1, the intermediate terminal N3, and the output terminal N2 are within a predetermined range and are similar to each other.

The switch diagnosis unit <NUM> according to an embodiment may sense an error in the charging switch unit <NUM> by using relationships between the voltages VN1, VN3, and VN2 of the input terminal N1, the intermediate terminal N3, and the output terminal N2 illustrated in <FIG>.

<FIG> illustrates a flowchart showing a diagnosis method for detecting an error in a charging switch unit according to an embodiment.

The diagnostic method illustrated in <FIG> may be performed whenever a switching operation occurs.

First, a switch control command for instructing a switching operation of the charging switch unit <NUM> is generated (S1). The BMS <NUM> may receive a switch control command from an electronic control circuit of an external device to which the battery system <NUM> is applied. Alternatively, the BMS <NUM> may generate a switch control command for battery management. Specifically, a configuration for receiving or generating a switch control command may be the main control circuit <NUM>.

The main control circuit <NUM> determines whether the switch control command is opened or closed (S2). When the switch control command indicates open, it is a command to cut off the connection between the charger <NUM> and the battery module <NUM>, and the charging switch unit <NUM> is turned off. When the switch control command indicates closed, it is a command for connecting the charger <NUM> and the battery module <NUM>, and the charging switch unit <NUM> is turned on.

As a result of the determination of step S2, when the switch control command indicates open, the main control circuit <NUM> generates the first charging control signal CHS1 at a disable level to transmit it to the gate driver <NUM>, and the gate driver <NUM> turns off the switches <NUM> to <NUM> by generating the gate voltage VG1 of an off level. Then, the first charging switch <NUM> is opened (S3).

When a predetermined time (e.g., <NUM>) has elapsed after step S3, the switch diagnosis unit <NUM> compares the voltage VN3 of the intermediate terminal N3 with the voltage VN2 of the output terminal N2 to determine whether the two voltages are similar (S4). When a difference between the voltage VN3 and the voltage VN2 is smaller than a predetermined threshold voltage, it may be determined that the two voltages are similar, and the threshold voltage may be set by adding a predetermined margin to a voltage at opposite ends in an on state of the second charging switch <NUM>.

When it is determined in step S4 that the voltage VN2 and the voltage VN3 are similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as a normal state. Subsequently, the main control circuit <NUM> controls the second charging switch <NUM> to open the second charging switch <NUM> (S5). Specifically, the switch diagnosis unit <NUM> transmits the determination result, that is, the determination result that the voltage VN2 and the voltage VN3 are similar to the main control circuit <NUM>, the main control circuit <NUM> generates the second charging control signal CHS2 at a disable level and transmits it to the gate driver <NUM>, and the gate driver <NUM> turns off the switches <NUM> to <NUM> by generating the gate voltage VG2 of an off level. Then, the second charging switch <NUM> is opened.

When it is determined in step S4 that the voltage VN2 and the voltage VN3 are not similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as an abnormal state, and depending on a diagnosis result thereof, the main control circuit <NUM> senses an error of the charging switch unit <NUM> (S6). When an error occurs in the first charging switch <NUM>, it is not normally opened, and thus the voltage VN3 may be affected by the voltage VN1 of the input terminal N1, so that the voltage VN3 and the voltage VN2 may not be similar. Upon sensing an error, the main control circuit <NUM> may initiate a protection operation to prevent damage to the battery system <NUM>. In a following description, the protection operation may include an operation of notifying a user of an error, an operation of controlling the charging switch to an open state until the charging switch is restored to a normal state, and the like.

As a result of the determination of step S2, when the switch control command indicates closed, the main control circuit <NUM> generates the first charging control signal CHS1 at an enable level to transmit it to the gate driver <NUM>, and the gate driver <NUM> turns on the switches <NUM> to <NUM> by generating the gate voltage VG1 of an on level. Then, the first charging switch <NUM> is closed (S7).

When a predetermined time (e.g., <NUM>) has elapsed after step S7, the switch diagnosis unit <NUM> compares the voltage VN3 of the intermediate terminal N3 with the voltage VN1 of the input terminal N1 to determine whether the two voltages are similar (S8). When a difference between the voltage VN3 and the voltage VN1 is smaller than a predetermined threshold voltage, it may be determined that the two voltages are similar, and the threshold voltage may be set by adding a predetermined margin to a voltage at opposite ends in an on state of the first charging switch <NUM>.

When it is determined in step S8 that the voltage VN1 and the voltage VN3 are similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as a normal state. Subsequently, the main control circuit <NUM> controls the second charging switch <NUM> to close the second charging switch <NUM> (S9). Specifically, the switch diagnosis unit <NUM> transmits the determination result, that is, the determination result that the voltage VN1 and the voltage VN3 are similar to the main control circuit <NUM>, the main control circuit <NUM> generates the second charging control signal CHS2 at an enable level and transmits it to the gate driver <NUM>, and the gate driver <NUM> turns on the switches <NUM> to <NUM> by generating the gate voltage VG2 of an on level. Then, the second charging switch <NUM> is closed.

When it is determined in step S8 that the voltage VN1 and the voltage VN3 are not similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as an abnormal state, and depending on a diagnosis result thereof, the main control circuit <NUM> senses an error of the charging switch unit <NUM> (S6). When an error occurs in the first charging switch <NUM>, the voltage VN3 and the voltage VN1 may not be similar to each other because the first charging switch <NUM> is not normally closed. Upon sensing an error, the main control circuit <NUM> may initiate a protection operation to prevent damage to the battery system <NUM>.

In <FIG>, it is illustrated that the first charging switch <NUM> in a configuration of the charging switch unit <NUM> is controlled before the second charging switch <NUM> depending on a switch control command, but the invention is not limited thereto.

The first charging switch <NUM> and the second charging switch <NUM> may be first alternately controlled depending on the switch control command.

<FIG> illustrates a flowchart showing a diagnosis method for sensing an error in a charging switch unit when a switch control command is to open according to an embodiment.

First, a switch control command indicating "open" is generated (S10).

The main control circuit <NUM> determines whether the remainder obtained by dividing a variable i by <NUM> is <NUM> (S11). The variable i is a variable that is set to first alternately control the first charging switch <NUM> and the second charging switch <NUM>. It is assumed that an initial value is <NUM>.

Since the determination result of step S11 is not <NUM>, the second charging switch <NUM> is opened under the control of the main control circuit <NUM> (S17). Specifically, the main control circuit <NUM> generates the second charging control signal CHS2 at a disable level to transmit it to the gate driver <NUM>, and the gate driver <NUM> turns off the switches <NUM> to <NUM> by generating the gate voltage VG2 of an off level. Then, the second charging switch <NUM> is opened.

Then, the variable i is increased by <NUM> (S18). For example, i becomes <NUM>.

When a predetermined time elapses after the second charging switch <NUM> is opened, the switch diagnosis unit <NUM> determines whether the voltage VN3 and the voltage VN1 are similar (S19).

When it is determined in step S19 that the voltage VN1 and the voltage VN3 are similar, the switch diagnosis unit <NUM> diagnoses the second charging switch <NUM> as a normal state. Subsequently, the main control circuit <NUM> controls the first charging switch <NUM> to open the first charging switch <NUM> (S20). Specifically, the switch diagnosis unit <NUM> transmits the determination result, that is, the determination result that the voltage VN1 and the voltage VN3 are similar to the main control circuit <NUM>, the main control circuit <NUM> generates the first charging control signal CHS1 at a disable level and transmits it to the gate driver <NUM>, and the gate driver <NUM> turns off the switches <NUM> to <NUM> by generating the gate voltage VG1 of an off level. Then, the first charging switch <NUM> is opened.

When it is determined in step S19 that the voltage VN1 and the voltage VN3 are not similar, the switch diagnosis unit <NUM> diagnoses the second charging switch <NUM> as an abnormal state, and depending on a diagnosis result thereof, the main control circuit <NUM> senses an error of the charging switch unit <NUM> (S16). When an error occurs in the second charging switch <NUM>, it is not normally opened, and thus the voltage VN3 may be affected by the voltage VN2 of the output terminal N2, so that the voltage VN3 and the voltage VN1 may not be similar. Upon sensing an error, the main control circuit <NUM> may initiate a protection operation to prevent damage to the battery system <NUM>.

Next, the switch control command "open" occurs, the main control circuit <NUM> determines whether the remainder obtained by dividing the variable i by <NUM> is <NUM> (S11). This switch control command "open" may be a switch control command generated after a switch control command "closed" occurs.

Since the variable i became <NUM> in the diagnosis depending on the previous switch control command "open", the determination result in step S11 is <NUM>. Accordingly, the first charging switch <NUM> is opened under the control of the main control circuit <NUM> (S12). Specifically, the main control circuit <NUM> generates the first charging control signal CHS1 at a disable level to transmit it to the gate driver <NUM>, and the gate driver <NUM> turns off the switches <NUM> to <NUM> by generating the gate voltage VG1 of an off level. Then, the first charging switch <NUM> is opened.

Then, the variable i is increased by <NUM> (S13). For example, the variable i becomes <NUM>.

When a predetermined time elapses after the first charging switch <NUM> is opened, the switch diagnosis unit <NUM> determines whether the voltage VN3 and the voltage VN2 are similar (S14).

When it is determined in step S14 that the voltage VN2 and the voltage VN3 are similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as a normal state. Subsequently, the main control circuit <NUM> controls the second charging switch <NUM> to open the second charging switch <NUM> (S15). Specifically, the switch diagnosis unit <NUM> transmits the determination result, that is, the determination result that the voltage VN2 and the voltage VN3 are similar to the main control circuit <NUM>, the main control circuit <NUM> generates the second charging control signal CHS2 at a disable level and transmits it to the gate driver <NUM>, and the gate driver <NUM> turns off the switches <NUM> to <NUM> by generating the gate voltage VG2 of an off level. Then, the second charging switch <NUM> is opened.

When it is determined in step S14 that the voltage VN2 and the voltage VN3 are not similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as an abnormal state, and depending on a diagnosis result thereof, the main control circuit <NUM> senses an error of the charging switch unit <NUM> (S16). When an error occurs in the first charging switch <NUM>, it is not normally opened, and thus the voltage VN3 may be affected by the voltage VN1 of the input terminal N1, so that the voltage VN3 and the voltage VN2 may not be similar. Upon sensing an error, the main control circuit <NUM> may initiate a protection operation to prevent damage to the battery system <NUM>.

<FIG> illustrates a flowchart showing a diagnosis method for sensing an error in a charging switch unit when a switch control command is closed according to an embodiment.

First, a switch control command indicating "closed" is generated (S21).

The main control circuit <NUM> determines whether the remainder obtained by dividing a variable j by <NUM> is <NUM> (S22). The variable j is a variable that is set to first alternately control the first charging switch <NUM> and the second charging switch <NUM>. It is assumed that an initial value is <NUM>.

Since the determination result of step S22 is not <NUM>, the second charging switch <NUM> is closed under the control of the main control circuit <NUM> (S28). Specifically, the main control circuit <NUM> generates the second charging control signal CHS2 at an enable level to transmit it to the gate driver <NUM>, and the gate driver <NUM> turns on the switches <NUM> to <NUM> by generating the gate voltage VG2 of an on level. Then, the second charging switch <NUM> is closed.

Then, the variable j is increased by <NUM> (S29). For example, j becomes <NUM>.

When a predetermined time elapses after the second charging switch <NUM> is closed, the switch diagnosis unit <NUM> determines whether the voltage VN3 and the voltage VN2 are similar (S30).

When it is determined in step S30 that the voltage VN2 and the voltage VN3 are similar, the switch diagnosis unit <NUM> diagnoses the second charging switch <NUM> as a normal state. Subsequently, the main control circuit <NUM> controls the first charging switch <NUM> to close the first charging switch <NUM> (S31). Specifically, the switch diagnosis unit <NUM> transmits the determination result, that is, the determination result that the voltage VN2 and the voltage VN3 are similar to the main control circuit <NUM>, the main control circuit <NUM> generates the first charging control signal CHS1 at an enable level and transmits it to the gate driver <NUM>, and the gate driver <NUM> turns on the switches <NUM> to <NUM> by generating the gate voltage VG1 of an on level. Then, the first charging switch <NUM> is closed.

When it is determined in step S30 that the voltage VN2 and the voltage VN3 are not similar, the switch diagnosis unit <NUM> diagnoses the second charging switch <NUM> as an abnormal state, and depending on a diagnosis result thereof, the main control circuit <NUM> senses an error of the charging switch unit <NUM> (S27). When an error occurs in the second charging switch <NUM>, the voltage VN3 and the voltage VN2 may not be similar to each other because the first charging switch <NUM> is not normally closed. Upon sensing an error, the main control circuit <NUM> may initiate a protection operation to prevent damage to the battery system <NUM>.

Next, the switch control command "closed" occurs, the main control circuit <NUM> determines whether the remainder obtained by dividing the variable j by <NUM> is <NUM> (S11). This switch control command "closed" may be a switch control command generated after a switch control command "open" occurs.

Since the variable j became <NUM> in the diagnosis depending on the previous switch control command "closed", the determination result in step S22 is <NUM>. Accordingly, the first charging switch <NUM> is closed under the control of the main control circuit <NUM> (S23). Specifically, the main control circuit <NUM> generates the first charging control signal CHS1 at an enable level to transmit it to the gate driver <NUM>, and the gate driver <NUM> turns on the switches <NUM> to <NUM> by generating the gate voltage VG1 of an on level. Then, the first charging switch <NUM> is closed.

Then, the variable j is increased by <NUM> (S13). For example, the variable j becomes <NUM>.

When a predetermined time elapses after the first charging switch <NUM> is closed, the switch diagnosis unit <NUM> determines whether the voltage VN3 and the voltage VN1 are similar (S14).

When it is determined in step S25 that the voltage VN1 and the voltage VN3 are similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as a normal state. Subsequently, the main control circuit <NUM> controls the second charging switch <NUM> to close the second charging switch <NUM> (S26). Specifically, the switch diagnosis unit <NUM> transmits the determination result, that is, the determination result that the voltage VN1 and the voltage VN3 are similar to the main control circuit <NUM>, the main control circuit <NUM> generates the second charging control signal CHS2 at an enable level and transmits it to the gate driver <NUM>, and the gate driver <NUM> turns on the switches <NUM> to <NUM> by generating the gate voltage VG2 of an on level. Then, the second charging switch <NUM> is closed.

When it is determined in step S25 that the voltage VN1 and the voltage VN3 are not similar, the switch diagnosis unit <NUM> diagnoses the first charging switch <NUM> as an abnormal state, and depending on a diagnosis result thereof, the main control circuit <NUM> senses an error of the charging switch unit <NUM> (S27). When an error occurs in the first charging switch <NUM>, the voltage VN3 and the voltage VN1 may not be similar to each other because the first charging switch <NUM> is not normally closed. Upon sensing an error, the main control circuit <NUM> may initiate a protection operation to prevent damage to the battery system <NUM>.

Claim 1:
An error detecting method of a charging switch unit including a first charging switch (<NUM>) and a second charging switch (<NUM>) connected to a charging line of a battery (<NUM>), the method comprising:
switching the first charging switch (<NUM>) according to a switch control command;
in response to the first charging switch (<NUM>) being switched to open and the second charging switch (<NUM>) being closed:
determining whether the difference between voltages at opposite ends of the second charging switch (<NUM>) are within a predetermined range; and
determining that the first charging switch (<NUM>) is normal in response to the voltages at the opposite ends of the second charging switch (<NUM>) being within the predetermined range;
in response to the first charging switch (<NUM>) being switched to closed and the second charging switch (<NUM>) being open:
determining whether the difference between voltages at the opposite ends of the first charging switch (<NUM>) are within the predetermined range; and
determining that the first charging switch (<NUM>) is normal in response to the voltages at the opposite ends of the first charging switch (<NUM>) being within the predetermined range.