Discharge method for link capacitor and vehicle system providing same

Abstract

The present invention relates to a method for discharging a link capacitor and a vehicle system providing same. The vehicle system of the present invention comprises: a battery; a link capacitor connected in parallel to the battery; an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between positive and negative electrodes of the battery; and a battery management system (BMS) for controlling the auxiliary discharge switch to be turned on when the magnitude of a link voltage, which is the voltage across both ends of the link capacitor, is equal to or greater than a reference value after the link capacitor is discharged by a main discharge circuit connected in parallel to the link capacitor.

Description

Method for discharging a link capacitor and an automotive system providing the method

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0104174, filed August 9, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a method for discharging a link capacitor and an automobile system providing the method.

[0004] In a vehicle that runs on battery power, such as an electric vehicle (EV), a battery system that connects a load device and a battery may include a battery, a contactor (or relay), a current sensor, a BMS (Battery Management System) that controls the battery and the contactor, and a link capacitor (DC Link-Cap, X-cap) for smoothing purposes that is connected in parallel with the battery.

[0005] The contactor section may include a precharge contactor, a precharge resistor, and a main contactor. First, when the precharge contactor is turned on, the link capacitor (X-cap) is charged while the surge current is limited by the precharge resistor. Then, when the main contactor is turned on and the precharge contactor is turned off, charging or discharging can be performed between the battery and an external device (motor, charger, etc.).

[0006] During the discharge process of the battery, charge is first accumulated in the link capacitor (X-cap), thereby smoothing the power from the battery, and the smoothed power is supplied to an external device (such as a motor). As a result, the battery system can supply stable power to the load device. In addition, during the charge process of the battery, the link capacitor (X-cap) smoothes the power from an external device (such as a charger), and the smoothed power can be supplied to the battery.

[0007] Meanwhile, if a contactor fails, the electrical connection between the battery and external devices cannot be properly controlled. Examples of physical contactor failures include a stuck-close failure, in which the contactor is welded closed, or a stuck-open failure, in which the contactor is welded open.

[0008] In relation to the diagnosis of a contactor failure, a method has been used in the past of measuring the voltage across the battery and the voltage across the link capacitor (X-cap) when the contactor is turned on, calculating the difference between the voltage across the battery and the voltage across the link capacitor, and comparing the calculated difference with an error value.

[0009] In addition to diagnosing the failure of a precise contactor, in various situations such as a car crash, the charge remaining in the link capacitor (DC Link-Cap) must be discharged by the discharge circuit on the vehicle side.

[0010] If the link capacitor (DC Link-Cap) is not sufficiently discharged, a misdiagnosis problem may occur in contactor failure diagnosis, or various problems may occur during the automobile maintenance process.

[0011] The present invention relates to a battery system that provides a method for discharging a link capacitor and an automobile system that provides the method, which can discharge a link capacitor even in an emergency situation such as when a discharge circuit on the vehicle side malfunctions.

[0012] An automobile system according to one aspect of the present invention includes a battery, a link capacitor connected in parallel with the battery, an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative poles of the battery, and a BMS (Battery Management System) that turns on the auxiliary discharge switch when the link voltage, which is a voltage across the link capacitor, is greater than a reference value after the link capacitor is discharged by a main discharge circuit connected in parallel with the link capacitor.

[0013] The above automotive system may further include a main discharge circuit including a main discharge resistor and a main discharge switch connected in series between the positive and negative electrodes of the battery.

[0014] The above-described automobile system may further include an upper controller that controls turning on the main discharge switch when an emergency event occurs, and instructs the BMS to control turning on the auxiliary discharge switch when the size of the link voltage is greater than or equal to the reference value after the main discharge switch is controlled.

[0015] The above automotive system further includes a main contactor connected between the positive electrode of the battery and one end of the link capacitor, and the BMS can control turning off the main contactor when the emergency event occurs.

[0016] The above-mentioned automotive system may further include a battery system including the battery, the main contactor, the auxiliary discharge circuit, and the BMS.

[0017] The BMS can generate a first fault alarm message including fault status information of the main discharge circuit and a second fault alarm message including fault status information of the auxiliary discharge circuit when the magnitude of the link voltage is greater than or equal to the reference value after the auxiliary discharge switch is turned on.

[0018] The BMS can generate a first fault alarm message including fault status information of the main discharge circuit when the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch is turned on.

[0019] The above BMS can diagnose a fusion failure of the main contactor if the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch is turned on.

[0020] The BMS can calculate the difference between the battery voltage, which is the voltage at both ends of the battery, and the link voltage, and compare the difference with a predetermined error value to diagnose a fusion failure of the main contactor.

[0021] According to another feature of the present invention, a method for discharging a link capacitor according to a feature of the present invention is provided in an automobile system including a main discharge circuit including a main discharge resistor and a main discharge switch connected in series between a positive electrode and a negative electrode of a battery, and an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive electrode and the negative electrode of the battery, a method for discharging a link capacitor connected in parallel with the battery, the method comprising: a step of a BMS (Battery Management System) turning off a main contactor connected between the positive electrode of the battery and one end of the link capacitor under the instruction of a higher controller when an emergency event occurs; a step of the upper controller controlling the main discharge switch to turn on; a step of the upper controller determining whether the link voltage is less than a reference value after the main discharge switch is controlled; a step of the BMS controlling the auxiliary discharge switch to turn on if the link voltage is greater than or equal to the reference value; a step of the BMS determining whether the link voltage is less than the reference value after the auxiliary discharge switch is controlled; and a step of the BMS controlling the main contactor if the link voltage is less than the reference value if the link voltage is less than the reference value. It includes a step of diagnosing a fusion failure.

[0022] The method for discharging the link capacitor may further include, after the step of determining whether the size of the link voltage is less than the reference value after the auxiliary discharge switch is controlled, a step of generating, by the BMS, a first failure alarm message including failure status information of the main discharge circuit and a second failure alarm message including failure status information of the auxiliary discharge circuit if the size of the link voltage is greater than the reference value as a result of the determination.

[0023] The method for discharging the link capacitor may further include, prior to the step of diagnosing a fusion failure of the main contactor, a step of generating a first failure alarm message including failure status information of the main discharge circuit by the BMS when the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch is controlled.

[0024] The step of diagnosing a fusion failure of the main contactor may include the BMS calculating a difference value between the size of the battery voltage, which is the voltage at both ends of the battery, and the size of the link voltage, and comparing the difference value with a predetermined error value to diagnose a fusion failure of the main contactor.

[0025] The present invention can sufficiently discharge a link capacitor (DC Link-Cap, X-cap) by using an auxiliary discharge circuit on the battery system side even when the main discharge circuit on the vehicle side cannot perform its original function.

[0026] The present invention can reduce the cost of replacing a normal contactor due to a misdiagnosis by precisely diagnosing a stuck open fault of a contactor, and can quickly detect the cause of a defect when a defect occurs in a battery system.

[0027] The present invention ensures the safety of workers servicing automobiles by sufficiently discharging a link capacitor (DC Link-Cap, X-cap) in an emergency situation such as a vehicle collision, and can promptly provide workers with the cause of a problem in the automobile during automobile maintenance.

[0028] FIG. 1 is a block diagram illustrating an automotive system according to one embodiment.

[0029] Figure 2 is a circuit diagram explaining Figure 1 in detail.

[0030] FIG. 3 is a drawing illustrating the functions of a main discharge circuit and an auxiliary discharge circuit according to one embodiment.

[0031] Fig. 4 is a flowchart illustrating a method for discharging a link capacitor according to one embodiment.

[0032] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the attached drawings. The same or similar components will be given the same or similar drawing reference numerals, and redundant descriptions thereof will be omitted. The suffixes "module" and / or "part" used for components in the following description are given or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[0033] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0034] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0035] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0036]

[0037] FIG. 1 is a block diagram illustrating an automotive system according to one embodiment, FIG. 2 is a circuit diagram illustrating FIG. 1 in detail, and FIG. 3 is a diagram illustrating the functions of a main discharge circuit and an auxiliary discharge circuit according to one embodiment.

[0038] Referring to FIG. 1, the automobile system (10) includes a battery system (100), a load device (200), and an upper controller (300).

[0039] Referring to FIGS. 1 and 2, the battery system (100) includes a battery (110), a BMS (Battery Management System) (120), an auxiliary discharge circuit (130), and a positive main contactor (POS_Rely). Depending on the embodiment, the battery system (100) may further include a negative main contactor (NEG_Rely), a precharge contactor (Pre_Rely), and a precharge resistor (Pre_Res).

[0040] In FIGS. 1 to 3, a battery (110) is connected between two output terminals (OUT1, OUT2) of a battery system (100), a positive main contactor (POS_Rely) is connected between the positive pole of the battery (110) and the first output terminal (OUT1), and a negative main contactor (NEG_Rely) is connected between the negative pole of the battery (110) and the second output terminal (OUT2). The configurations and connection relationships between the configurations illustrated in FIG. 1 are merely examples, and the invention is not limited thereto.

[0041] The battery (110) may include a plurality of battery cells electrically connected in series and parallel. In some embodiments, the battery cells may be rechargeable secondary batteries. For example, in charging mode, the battery (110) may supply power to the load device (200).

[0042] The BMS (120) can control the overall battery system (100). According to an embodiment, when an emergency event occurs, the BMS (120) can control the auxiliary discharge circuit (130) to discharge the link capacitor (DC Link-Cap, X-cap).

[0043] The auxiliary discharge circuit (130) may include an auxiliary discharge resistor (Dis_Res2) and an auxiliary discharge switch (Dis_SW2).

[0044] Referring to Fig. 2, an auxiliary discharge resistor (Dis_Res2) and an auxiliary discharge switch (Dis_SW2) can be connected in series between the positive and negative poles of the battery (110). For example, the size of the auxiliary discharge resistor (Dis_Res2) can be set to various values ​​depending on the experiment.

[0045] When the positive main contactor (POS_Rely) and the negative main contactor (NEG_Rely) are turned on, the battery system (100) and the load device (200) are electrically connected. Then, power from the battery (110) is supplied to the load device (200), so that the automobile system (10) can perform a preset operation. Hereinafter, the main contactor may be indicated to include a positive main contactor (POS_Rely) and a negative main contactor (NEG_Rely).

[0046] The precharge resistor (Pre_Res) and the precharge contactor (Pre_Rely) may be connected in series between the positive electrode of the battery (110) and the first output terminal (OUT1). The precharge resistor (Pre_Res) and the precharge contactor (Pre_Rely) may be connected in series between one end and the other end of the positive main contactor (POS_Rely).

[0047] The pre-charge contactor (Pre_Rely) can reduce the surge current that occurs when the positive main contactor (POS_Rely) is connected to the load device (200), thereby preventing damage to the positive main contactor (POS_Rely) and the battery (110).

[0048] The precharge contactor (Pre_Rely) can perform pre-charge. Specifically, when the precharge contactor (Pre_Rely) is turned on, the link capacitor (X-cap) can slowly accumulate charge by receiving a microcurrent reduced by the precharge resistor (Pre_Res). Thereafter, the positive main contactor (POS_Rely) is turned on, and after a predetermined time has elapsed while the precharge contactor (Pre_Rely) and the positive main contactor (POS_Rely) are in the on state, the precharge contactor (Pre_Rely) can be turned off. Then, when the positive main contactor (POS_Rely) is connected to the load device (200), the surge current can be reduced.

[0049] The positive main contactor (POS_Rely) may be connected between the positive terminal of the battery (110) and the load device (200). Referring to FIG. 1, the positive main contactor (POS_Rely) may be connected in parallel with the precharge resistor (Pre_Res) and the precharge contactor (Pre_Rely). When the positive main contactor (POS_Rely) is turned on, the battery (110) and the load device (200) are electrically connected, so that charging or discharging of the battery (110) may be performed.

[0050] The load device (200) may be a device that receives power from the battery system (100) and drives the automobile system (10).

[0051] Referring to FIG. 2, the load device (200) includes a motor (210), an inverter (220), and a main discharge circuit (230). According to an embodiment, the load device (200) may further include a link capacitor (X-cap), a plurality of Y-capacitors (Y-cap_1, Y-cap_2), and a plurality of load resistors (Y-Res_1, Y-Res_2). In FIGS. 2 and 3, the link capacitor (X-cap) is illustrated as being included in the load device (200), but is not limited thereto, and the link capacitor (X-cap) may also be included in the battery system (100).

[0052] The motor (210) may be a device that converts electrical energy into rotational kinetic energy. The inverter (220) may convert the direct current supplied by the battery (110) into alternating current and supply it to the motor (210). Since the motor (210), inverter (220), etc. are conventionally well-known components, a detailed description thereof will be omitted.

[0053] The main discharge circuit (230) may include a main discharge resistor (Dis_Res1) and a main discharge switch (Dis_SW1). Referring to FIG. 2, the main discharge resistor (Dis_Res1) and the main discharge switch (Dis_SW1) may be connected in series between both ends of the inverter (220). The main discharge resistor (Dis_Res1) and the main discharge switch (Dis_SW1) may be connected in series between the first output terminal (OUT1) and the second output terminal (OUT2) of the battery system (100).

[0054] According to an embodiment, when an emergency event occurs during operation of the vehicle system (10), the BMS (12) controls the main contactor (POS_Rely, NEG_Rely) to be turned off. For example, the emergency event may include an event such as the vehicle system (10) colliding with an external vehicle system. In an emergency event situation, in order to prevent secondary accidents such as a battery (110) ignition, the upper controller (300) may transmit the occurrence of the emergency event to the BMS (12), and the BMS (12) may control the main contactor (POS_Rely, NEG_Rely) to be turned off.

[0055] Next, when an emergency event occurs, a safety diagnosis of the entire automotive system (10) and / or the entire battery system (100) may be required. For this purpose, it is important to preemptively discharge the link capacitor (X-cap) as quickly as possible.

[0056] For example, in the event of a physical failure, such as a stuck-close failure in which the main contactor (POS_Rely, NEG_Rely) is welded in a closed state (close) or a stuck-open failure in which the main contactor (POS_Rely, NEG_Rely) is welded in an open state (open), the main contactor (POS_Rely, NEG_Rely) may not be turned off switched under the control of the BMS (12). In some embodiments, when an emergency event occurs, a safety diagnosis may be performed on whether the main contactor (POS_Rely, NEG_Rely) is turned off switched normally. At this time, if a failure diagnosis of the main contactor (POS_Rely, NEG_Rely) is performed in a state in which all charges stored in the link capacitor (X-cap) are not discharged, a problem of misdiagnosis may occur. Below, a method for discharging a link capacitor (DC Link-Cap, X-cap) when an emergency event occurs in FIG. 6 is described in detail.

[0057] The link capacitor (DC Link-Cap, X-cap) may be a smoothing capacitor (DC_Link Capacitor). For example, the link capacitor (X-cap) may function as a buffer between the battery (110) and the inverter (220), thereby preventing a large voltage difference from occurring between the battery (110) and the inverter (220).

[0058] The plurality of Y-capacitors (Y-cap_1, Y-cap_2) may include a first Y-capacitor (Y-cap_1) and a second Y-capacitor (Y-cap_1). The first Y-capacitor (Y-cap_1) and the second Y-capacitor (Y-cap_1) may be connected in series between the (+) terminal and the (-) terminal of the load-side link. A node between the first Y-capacitor (Y-cap_1) and the second Y-capacitor (Y-cap_1) may be connected to ground. The plurality of load resistors (Y-Res_1, Y-Res_2) may include a first load resistor (Y-Res_1) and a second load resistor (Y-Res_2). The first load resistor (Y-Res_1) and the second load resistor (Y-Res_2) can be connected in series between the (+) terminal and the (-) terminal of the load-side link. The node between the first load resistor (Y-Res_1) and the second load resistor (Y-Res_2) can be connected to the ground. The multiple Y-capacitors (Y-cap_1, Y-cap_2) and the multiple load resistors (Y-Res_1, Y-Res_2) are components widely installed in existing automobile systems, and a detailed description thereof is omitted.

[0059] The upper controller (300) can control the overall automotive system (10). The upper controller (300) can communicate with the BMS (120) and monitor the status of the battery system (100). The upper controller (300) can control the battery system (100) through the BMS (120).

[0060] According to an embodiment, when an emergency event occurs, the upper controller (300) can control the main contactor (POS_Rely, NEG_Rely) to turn off through the BMS (120). In addition, the upper controller (300) can directly control the main discharge switch (Dis_SW1) of the main discharge circuit (230) to turn on, thereby discharging the link capacitor (X-cap). In addition, the upper controller (300) can control the BMS (120) to turn on the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit (130).

[0061] Referring to FIG. 3, first, when the main discharge switch (Dis_SW1) of the main discharge circuit (230) is turned on under the control of the upper controller (300), the charge stored in the link capacitor (X-cap) can be consumed through the main discharge resistor (Dis_Res1) (direction ①). If the link capacitor (X-cap) is not sufficiently discharged by the main discharge circuit (230), the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit (130) can be turned on under the control of the BMS (120). Then, the charge stored in the link capacitor (X-cap) can be consumed through the auxiliary discharge resistor (Dis_Res2) (direction ②).

[0062] According to an embodiment, by sufficiently discharging the link capacitor (X-cap) to a desired target through the main discharge circuit (230) and the auxiliary discharge circuit (130), it is possible to prevent misdiagnosis problems when performing various safety diagnoses.

[0063]

[0064] Fig. 4 is a flowchart illustrating a method for discharging a link capacitor according to one embodiment.

[0065] Referring to Fig. 4, when an emergency event occurs, the BMS (12) turns off the main contactor (POS_Rely, NEG_Rely) (S110, S120).

[0066] An emergency event may include an emergency situation that threatens the safety of the vehicle system (10), such as a collision with an external object of the vehicle system (10), a failure of the vehicle system (10), etc. For example, an emergency event may include various events that require the main contactor (POS_Rely, NEG_Rely) to be turned off.

[0067] The upper controller (300) determines the occurrence of an emergency event corresponding to a preset situation, and when an emergency event occurs, it can transmit the occurrence of the emergency event to the BMS (12). Then, the BMS (12) can control the turn-off of the main contactor (POS_Rely, NEG_Rely).

[0068] In a normal state, the main contactor (POS_Rely, NEG_Rely) can perform normal turn-off switching operation under the control of the BMS (12). However, in a state where a physical failure such as stuck-close and stuck-open occurs, the main contactor (POS_Rely, NEG_Rely) may not be able to perform physical turn-off switching even if it receives a turn-off control signal from the BMS (12). That is, when an emergency event occurs, the main contactor (POS_Rely, NEG_Rely) should be turned off, but a problem occurs in which it is not turned off. Therefore, after transmitting the turn-off control signal, a process is required to diagnose whether the actual main contactor (POS_Rely, NEG_Rely) has been turned off and to check the status of the main contactor (POS_Rely, NEG_Rely).

[0069] Next, the upper controller (300) turns on the main discharge switch (Dis_SW1) of the main discharge circuit (230) mounted on the load device (200) (S130).

[0070] The diagnosis of a fusion failure of the main contactor (POS_Rely, NEG_Rely) can be performed by calculating the difference between the size of the battery voltage, which is the voltage across the battery (110), and the size of the link voltage, which is the voltage across the link capacitor (X-cap), and comparing the difference with a predetermined error value. Therefore, if the link capacitor (X-cap) is not sufficiently discharged, the diagnosis of a fusion failure of the main contactor (POS_Rely, NEG_Rely) may have low accuracy. According to an embodiment, the upper controller (300) turns on the main discharge switch (Dis_SW1) of the main discharge circuit (230). Then, the charge stored in the link capacitor (X-cap) can be consumed through the main discharge resistor (Dis_Res1).

[0071] Next, the upper controller (300) determines whether the size of the link voltage, which is the voltage across the two terminals of the link capacitor (X-cap), is less than a reference value (S140).

[0072] The upper controller (300) can receive the size of the link voltage from a voltage device (not shown) that measures the voltage across the link capacitor (X-cap).

[0073] For example, the reference value may correspond to a voltage value including a predetermined error value with respect to the ground level. If the link capacitor (X-cap) is sufficiently discharged, the magnitude of the link voltage may correspond to the ground level. If the magnitude of the link voltage is greater than or equal to the reference value, it may indicate a state in which the link capacitor (X-cap) is not sufficiently discharged by the main discharge circuit (230). Therefore, if the magnitude of the link voltage is greater than or equal to the reference value, it may indicate a failure state of the main discharge circuit (230).

[0074] Next, if the link voltage is less than the reference value (S140, YES), the BMS (12) diagnoses a fusion failure of the main contactor (POS_Rely, NEG_Rely) (S150).

[0075] For example, if the link voltage is less than the reference value, the upper controller (300) can instruct the BMS (12) to diagnose a fusion failure of the main contactor (POS_Rely, NEG_Rely).

[0076] The BMS (12) can receive the magnitude of the battery voltage from a voltage device (not shown) that measures the voltage across the battery (110). The BMS (12) can receive the magnitude of the link voltage from a voltage device (not shown) that measures the voltage across the link capacitor (X-cap). For example, when the link capacitor (X-cap) is mounted on the battery system (100), the BMS (12) can receive the magnitude of the link voltage directly from the voltage device. For another example, when the link capacitor (X-cap) is mounted on the load device (200), the BMS (12) can receive the magnitude of the link voltage through the upper controller (300).

[0077] The BMS (12) calculates the difference between the battery voltage and the link voltage. For example, if the difference is greater than a predetermined error value, the BMS (12) can diagnose that the main contactor (POS_Rely, NEG_Rely) has normally turned off according to the turn-off control signal. For another example, if the difference is less than a predetermined error value, the BMS (12) can diagnose that the main contactor (POS_Rely, NEG_Rely) is in a stuck-closed fault state in which it is welded in a closed state.

[0078] Next, if the link voltage is greater than or equal to the reference value (S140, YES), the BMS (12) turns on the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit (130) mounted on the battery system (100) (S160).

[0079] For example, the upper controller (300) may instruct the BMS (12) to turn on the auxiliary discharge switch (Dis_SW2) of the auxiliary discharge circuit (130). Then, the charge stored in the link capacitor (X-cap) may be consumed through the auxiliary discharge resistor (Dis_Res2). In an embodiment, when the link capacitor (X-cap) is not sufficiently discharged by the main discharge circuit (230), the link capacitor (X-cap) may be additionally discharged by the auxiliary discharge circuit (130).

[0080] Next, BMS (12) determines whether the size of the link voltage, which is the voltage at both ends of the link capacitor (X-cap), is less than the reference value (S170).

[0081] The BMS (12) can receive the magnitude of the link voltage from a voltage device (not shown) that measures the voltage across the link capacitor (X-cap). For example, when the link capacitor (X-cap) is mounted on the battery system (100), the BMS (12) can receive the magnitude of the link voltage directly from the voltage device. For another example, when the link capacitor (X-cap) is mounted on the load device (200), the BMS (12) can receive the magnitude of the link voltage through the upper controller (300).

[0082] Next, if the size of the link voltage is less than the reference value (S170, YES), the BMS (12) generates a failure notification message of the main discharge circuit (230) and diagnoses a fusion failure of the main contactor (POS_Rely, NEG_Rely) (S150, S180).

[0083] Step S180, which generates a first failure notification message including information on a failure state of the main discharge circuit (230), is not limited to being performed after step S170. According to another embodiment, step S180 may be performed after step S140. In addition, the step of diagnosing a fusion failure of the main contactor (POS_Rely, NEG_Rely) performed after step S180 may be the same step as the step of diagnosing a fusion failure of the main contactor (POS_Rely, NEG_Rely) performed after step S140. Therefore, a detailed description thereof is omitted.

[0084] For example, when the BMS (12) transmits information about a state in which the link voltage is less than a reference value to the upper controller (300), the upper controller (300) can generate a first failure notification message and display it to the user.

[0085] For another example, when the BMS (12) generates a first failure notification message including information on a failure state of the main discharge circuit (230) and transmits it to the upper controller (300), the upper controller (300) can display the first failure notification message to the user.

[0086] Next, if the size of the link voltage is greater than or equal to the reference value (S170, YES), the BMS (12) generates a first failure notification message including information on a failure state of the main discharge circuit (230) and a second failure notification message including information on a failure state of the auxiliary discharge circuit (130) (S190).

[0087] Step S190, which generates a first failure notification message including information on a failure state of the main discharge circuit (230), is not limited to being performed after step S180. According to another embodiment, the step of generating the first failure notification message in step S190 may be performed after step S140. At this time, in step S190, the BMS (12) may generate only the second failure notification message and transmit the second failure notification message to the upper controller (300).

[0088] The upper controller (300) can display a first failure notification message and a second failure notification message to the user. In addition, since the link capacitor (X-cap) is not sufficiently discharged, the BMS (12) may not diagnose a fusion failure of the main contactor (POS_Rely, NEG_Rely).

[0089] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by a person having ordinary skill in the art to which the present invention pertains also fall within the scope of the present invention.

Claims

1. Battery, A link capacitor connected in parallel with the above battery, An auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative poles of the battery, and An automobile system including a BMS (Battery Management System) that turns on the auxiliary discharge switch when the link voltage, which is the voltage across the link capacitor, is greater than a reference value after the link capacitor is discharged by a main discharge circuit connected in parallel with the link capacitor.

2. In paragraph 1, An automotive system further comprising a main discharge circuit including a main discharge resistor and a main discharge switch connected in series between the positive and negative electrodes of the battery.

3. In paragraph 2, When an emergency event occurs, the upper controller controls the turn-on of the main discharge switch, and if the size of the link voltage is greater than the reference value after the main discharge switch is controlled, instructs the BMS to control the turn-on of the auxiliary discharge switch. An automotive system further comprising:

4. In paragraph 3, Further comprising a main contactor connected between the positive electrode of the battery and one end of the link capacitor, The above BMS is, An automotive system that controls turning off the main contactor when the above emergency event occurs.

5. In paragraph 4, An automobile system further comprising a battery system including the battery, the main contactor, the auxiliary discharge circuit, and the BMS.

6. In paragraph 4, The above BMS is, An automobile system characterized in that, when the magnitude of the link voltage is greater than or equal to the reference value after the auxiliary discharge switch is turned on, a first failure alarm message including failure status information of the main discharge circuit and a second failure alarm message including failure status information of the auxiliary discharge circuit are generated.

7. In paragraph 4, The above BMS is, An automobile system characterized in that, when the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch is turned on, a first failure alarm message including failure status information of the main discharge circuit is generated.

8. In paragraph 4, The above BMS is, An automobile system that diagnoses a fusion failure of the main contactor when the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch is turned on.

9. In paragraph 8, The above BMS is, An automobile system that calculates the difference between the size of the battery voltage, which is the voltage at both ends of the battery, and the size of the link voltage, and compares the difference with a predetermined error value to diagnose a fusion failure of the main contactor.

10. A method for discharging a link capacitor connected in parallel with the battery in an automobile system comprising a main discharge circuit including a main discharge resistor and a main discharge switch connected in series between the positive and negative poles of the battery, and an auxiliary discharge circuit including an auxiliary discharge resistor and an auxiliary discharge switch connected in series between the positive and negative poles of the battery, When an emergency event occurs, a step for the BMS (Battery Management System) to turn off the main contactor connected between the positive electrode of the battery and one end of the link capacitor under the instruction of the upper controller; A step in which the upper controller turns on the main discharge switch, A step in which the upper controller determines whether the size of the link voltage is less than a reference value after the main discharge switch is controlled; If the size of the link voltage is greater than or equal to the reference value as a result of the above judgment, the step of the BMS controlling the auxiliary discharge switch to turn on; The step of the BMS determining whether the size of the link voltage is less than the reference value after the auxiliary discharge switch is controlled; A method for discharging a link capacitor, including a step of the BMS diagnosing a fusion failure of the main contactor when the size of the link voltage is less than the reference value as a result of the above judgment.

11. In paragraph 10, After the step of determining whether the size of the link voltage is less than the reference value after the auxiliary discharge switch is controlled, A method for discharging a link capacitor, further comprising the step of generating, by the BMS, a first failure alarm message including failure status information of the main discharge circuit and a second failure alarm message including failure status information of the auxiliary discharge circuit, if the size of the link voltage is greater than or equal to the reference value as a result of the determination.

12. In paragraph 10, Before the step of diagnosing the fusion failure of the above main contactor, A method for discharging a link capacitor, further comprising the step of: when the magnitude of the link voltage is less than the reference value after the auxiliary discharge switch is controlled, the BMS generates a first failure alarm message including failure status information of the main discharge circuit.

13. In paragraph 10, The steps for diagnosing the fusion failure of the above main contactor are: A method for discharging a link capacitor, characterized in that the BMS calculates a difference between the size of the battery voltage, which is the voltage at both ends of the battery, and the size of the link voltage, and compares the difference with a predetermined error value to diagnose a fusion failure of the main contactor.

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