Battery protection device and method for controlling the same

Abstract

The present invention is characterized by including a semiconductor circuit breaker that is arranged between a battery system and a line and has a semiconductor switch that electrically connects or insulates the battery system from the line depending on a voltage applied to a gate terminal, a cut-off switch that physically connects or separates the semiconductor circuit breaker from the line, and a rack battery management system that controls a gate driver that applies the gate voltage depending on a result of detecting a current flowing between the battery system and the line, thereby isolating the battery system from the line and controlling the cut-off switch to physically separate the semiconductor circuit breaker from the line.

Description

[Technical field]

[0001] The present invention relates to a battery protection unit (hereinafter referred to as BPU). [Background technology]

[0002] In general, a battery protection unit (BPU) is a device for protecting a battery system used in an energy storage system (ESS) or the like, and is composed of a battery system formed in a rack or module unit and a rack battery management system (RBMS) for protecting the battery system.

[0003] The rack battery management system manages switching of the charge / discharge mode of the battery system and monitors voltage, current, and temperature to protect the battery system. In addition, by cutting off the current output from the battery system or the current flowing into the battery system according to the result of the monitoring, the load can be protected from a short-circuit current flowing from the battery system when a power conditioning system (PCS) fails, and the battery system can be protected from an accident current such as a short circuit or a ground fault flowing in due to an accident occurring in a line between the power conditioning system (PCS) and the battery system. For this cutting function, the battery protection device includes a molded case circuit breaker (MCCB) that opens the line to cut off the line when an overcurrent is detected, and a fuse that melts down due to heat generated by the overcurrent to insulate the battery system from the line. In addition, the molded case circuit breaker and the fuse are disposed between the line to which a load is connected and the battery system, and prevent an overcurrent generated in the battery system or the line from flowing into the load or the battery system.

[0004] FIG. 1 is a diagram showing the structure of a typical battery protection device 100 in which a molded case circuit breaker and a fuse are disposed between a battery system and a line.

[0005] As shown in Fig. 1, a typical battery protection device 100 is connected to a battery system 110 having a battery rack 111 in which a plurality of batteries or cells are stacked in the form of a rack, and a line (DC link + 190, DC link - 191) to which a load is connected. Here, the positive terminal (+) of the battery rack 111 and the DC link positive terminal 190 are connected via a first fuse 121 and a first MCCB 131, and the negative terminal (-) of the battery system 111 and the DC link negative terminal 191 are connected via a second fuse 122 and a second MCCB 132.

[0006] A precharge relay 150 is provided between the first MCCB 131 and a DC link positive terminal 190. The precharge relay 150 includes a plurality of first main contactors 151, 152 connected in parallel to each other, and one of the first contactors 152 is connected to a resistor 153 of a predetermined size to form a bypass circuit for suppressing an inrush current generated when a load or a battery is initially connected. A second contactor 160 is provided between the second MCCB 132 and a DC link negative terminal 191. The first MCCB 131 and the second MCCB 132 further include an undervoltage trip coil (UVT) 140, and are configured to maintain a tripped state at a voltage equal to or lower than an operating voltage (e.g., a rated voltage).

[0007] Furthermore, an ammeter 180 is provided between the pre-charge relay 150 and the DC link positive end 190. Furthermore, an RBMS 170 is provided that controls the first MCCB 131, the second MCCB 132, the multiple first contactors 151, 152, and the second contactor 160 in response to the current between the battery system 100 and the line (DC link positive end (DC link +) 190) detected by the ammeter 180.

[0008] In the normal battery protection device 100 thus configured, when an overcurrent such as a short circuit current or a fault current occurs, the fuses 121, 122 are melted by heat generated by the inflow of the overcurrent, thereby providing primary protection for the battery system 111 or the load connected to the line. Secondarily, under the control of the RBMS 170, the first MCCB 131 and the second MCCB 132 open the electric circuit, and the line connection between the load and the battery is cut off, thereby providing secondary protection for the battery system 111 or the load.

[0009] However, since the MCCB and the like are mechanical switches, there is a problem that it takes a long time to cut off the line. Also, a fuse has a problem that the line remains connected until it is completely blown. Therefore, in the normal battery protection device 100, if the fuse is not completely blown before the MCCB completely cuts off the line when a short circuit current or an accident current occurs, there is a problem that the short circuit current generated in the battery system 111 may flow into the load through the line, or the accident current generated by the accident on the line may flow into the battery system 111. Also, there is a problem that such a short circuit current or accident current may cause damage to the battery system 111 or the load connected to the line.

[0010] Moreover, the fuse cuts off the connection between the battery system 111 and the line by melting, and if the fuse is melted by a short circuit current or a fault current (hereinafter collectively referred to as a fault current), the connection between the battery system 111 and the line cannot be restored unless it is replaced. Therefore, even if the fault on the line is resolved and the state of the current flowing in from the line is restored, the connection between the battery system 111 and the line is not automatically restored, so there is a problem that the user needs to manually replace the fuse every time the cutoff operation of the battery protection device 100 is performed. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made to solve the above problems and other problems, and aims to provide a battery protection device and a control method for the battery protection device that prevents an accident current caused by a battery short circuit or a line accident from flowing into a load or a battery before a fuse is completely blown.

[0012] Another object of the present invention is to provide a battery protection device and a control method for the battery protection device that prevent fuse burnout caused by accident current generated by a battery short circuit or a line accident, and automatically restores the connection between the battery system and the line when the current state is restored, without the user having to manually replace the fuse. [Means for solving the problem]

[0013] In order to achieve the above or other objects, according to one aspect of the present invention, a battery protection device according to an embodiment of the present invention is characterized in that it includes a semiconductor circuit breaker arranged between a battery system and a line, the semiconductor circuit breaker having a semiconductor switch that electrically connects or isolates the battery system from the line depending on a voltage applied to a gate terminal, a cut-off switch that physically connects or isolates the semiconductor circuit breaker from the line, and a rack battery management system (RBMS) that, when the battery system is connected to the line, controls a gate driver that applies the gate voltage depending on a result of detecting a current flowing between the battery system and the line, isolates the battery system from the line, and controls the cut-off switch to physically isolate the semiconductor circuit breaker from the line.

[0014] In one embodiment, the semiconductor circuit breaker includes a first semiconductor switch having a source terminal and a drain terminal arranged so that a current flow is formed from the battery system to the line, a second semiconductor switch connected in series with the first semiconductor switch and having a source terminal and a drain terminal arranged so that a current flow is formed from the line to the battery system, a first gate driver that applies a gate voltage to a gate terminal of the first semiconductor switch under the control of the rack battery management system, and a second gate driver that applies a gate voltage to a gate terminal of the second semiconductor switch under the control of the rack battery management system, and the rack battery management system is characterized in that when the battery system is physically connected to the line via the semiconductor circuit breaker, the rack battery management system controls at least one of the first and second gate drivers to apply a gate voltage having a predetermined voltage, thereby electrically connecting the battery system to the line.

[0015] In one embodiment, the rack battery management system controls the battery system to operate in either a discharge mode in which current is output from the battery system or a charge mode in which current is supplied to the battery system from the line, and controls either the first or second gate driver to apply a gate voltage less than the predetermined voltage depending on the current detection result, and which gate driver has a gate voltage controlled depending on the current detection result differs depending on the operation mode of the battery system.

[0016] In one embodiment, the rack battery management system controls the first gate driver to apply a gate voltage less than the predetermined voltage when the battery system is in a discharge mode, and controls the second gate driver to apply a gate voltage less than the predetermined voltage when the battery system is in a charge mode.

[0017] In one embodiment, the first and second semiconductor switches are each formed of an N-channel MOSFET element having a source terminal and a drain terminal arranged in an opposite direction to each other, and each includes a diode arranged in an opposite direction to a current flow of the N-channel MOSFET element.

[0018] In one embodiment, the semiconductor circuit breaker includes a current sensor that detects a current flowing between the battery system and a line, and the current sensor is a Giant MagnetoResistance (GMR) sensor that uses a GMR element.

[0019] In one embodiment, the positive terminal (+) and the negative terminal (-) of the battery system are each connected to the semiconductor switch via a fuse.

[0020] In one embodiment, the predetermined voltage is a threshold voltage that causes conduction between the input terminal and the output terminal of the first semiconductor switch or the second semiconductor switch.

[0021] In order to achieve the above or other objects, according to another aspect of the present invention, a control method for a battery protection device including a semiconductor circuit breaker connecting a battery system and a line according to an embodiment of the present invention includes a step in which a rack battery management system of the battery protection device controls a cut-off switch arranged between the semiconductor circuit breaker and the line, thereby physically connecting the battery system and the line; a step in which the rack battery management system controls a semiconductor switch provided in the semiconductor circuit breaker, thereby electrically connecting the battery system and the line; a step in which the rack battery management system detects an overcurrent of a predetermined magnitude or greater from a current flowing between the battery system and the line; a step in which the rack battery management system controls a gate driver that applies a gate voltage to the semiconductor switch according to a result of the detection, thereby isolating the battery system and the line; and a step in which the rack battery management system controls the cut-off switch and physically isolates the semiconductor circuit breaker from the line.

[0022] In one embodiment, the semiconductor circuit breaker includes a first semiconductor switch having a source terminal and a drain terminal arranged so that a current flow is formed from the battery system to the line, a second semiconductor switch connected in series with the first semiconductor switch and having a source terminal and a drain terminal arranged so that a current flow is formed from the line to the battery system, a first gate driver that applies a gate voltage to a gate terminal of the first semiconductor switch under the control of the rack battery management system, and a second gate driver that applies a gate voltage to a gate terminal of the second semiconductor switch under the control of the rack battery management system.

[0023] In one embodiment, the step of electrically connecting the battery system and the line includes the steps of driving the battery system in either a discharge mode or a charge mode, and controlling at least one of the first and second gate drivers to apply a gate voltage equal to or higher than a predetermined threshold voltage according to the operation mode of the battery system.

[0024] In one embodiment, the step of controlling the gate drivers and isolating the battery system from the line is characterized by controlling different gate drivers to apply gate voltages less than a predetermined threshold voltage depending on an operation mode of the battery system.

[0025] In one embodiment, the step of controlling different gate drivers according to an operation mode of the battery system is characterized in that, when the battery system operates in a discharge mode, the step of controlling the first gate driver to apply a gate voltage less than the threshold voltage, and when the battery system operates in a charge mode, the step of controlling the second gate driver to apply a gate voltage less than the threshold voltage.

[0026] In one embodiment, the step of controlling the gate driver to isolate the battery system from the line is characterized by controlling both the first gate driver and the second gate driver to apply a gate voltage less than a predetermined threshold voltage.

[0027] In one embodiment, the semiconductor circuit breaker includes a Giant MagnetoResistance (GMR) sensor as a current sensor, and the step of detecting the overcurrent is a step of detecting the overcurrent from a current flowing between the battery system and a line by the GMR sensor. Effect of the Invention

[0028] The effects of the battery protection device and the control method for the battery protection device according to the present invention will be described below.

[0029] According to at least one of the embodiments of the present invention, the battery system and the line are connected by a semiconductor switch, so that the time during which the line connection is cut off after the fault current is detected can be significantly shortened. Therefore, the present invention has an effect of preventing damage to the load or the battery due to the inflow of the fault current.

[0030] According to at least one of the embodiments of the present invention, the battery system and the line are connected by a semiconductor switch, so that the battery system and the line can be isolated from each other before the fuse is blown when a fault current occurs. Therefore, when the current state is restored, the connection between the battery system and the line is automatically restored without the need to replace the fuse. [Brief description of the drawings]

[0031] [Figure 1] 1 is a circuit diagram showing the structure of a typical battery protection device. [Diagram 2] 1 is a circuit diagram showing a structure of a battery protection device in which a battery system and a line are connected by a semiconductor switch in an embodiment of the present invention. [Diagram 3] 3 is a circuit diagram showing a structure of a semiconductor switch that connects a battery system and a line in the battery protection device of FIG. 2. [Figure 4] 4 is a graph showing the overcurrent detection performance of a GMR sensor provided in a battery protection device according to an embodiment of the present invention. [Diagram 5] 4 is a flowchart showing an operation process of an RBMS provided in a battery protection device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The technical terms used in this specification are merely used to describe a specific embodiment and do not limit the present invention. In addition, singular expressions used in this specification include plural expressions unless otherwise specified. The suffixes "module" and "part" for components used in the following description are given or mixed to facilitate the creation of the specification and do not have any significance or usefulness in themselves.

[0033] In this specification, the words "comprise", "include", etc. should not be construed as necessarily including all of the various components or steps in this specification, but rather as including none of the various components or steps, and may include additional components or steps.

[0034] Furthermore, when describing the technology disclosed in this specification, if it is determined that a specific description of related publicly known technology would obscure the gist of the technology disclosed in this specification, such a detailed description will be omitted.

[0035] Furthermore, the attached drawings are merely for the purpose of making the embodiments disclosed in this specification easily understandable, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include any modifications, equivalents, or alternatives within the spirit and technical scope of the present invention. Furthermore, it goes without saying that not only the embodiments described below, but also combinations thereof are included in the spirit and technical scope of the present invention as modifications, equivalents, or alternatives within the spirit and technical scope of the present invention.

[0036] First, in order to help a complete understanding of the present invention, the basic principle of the present invention will be described. Instead of a conventional molded circuit breaker that requires a relatively long time to break a circuit, the present invention uses a solid state circuit breaker (SSCB) that includes a semiconductor switch made of a power semiconductor having a high switching frequency and is capable of breaking a circuit at high speed to connect the battery system 110 to the lines (DC link +(190), DC link -(191)). In the event of an accident in the battery system 111 or the lines, the connection between the battery system 110 and the lines (DC link +(190), DC link -(191)) is broken in a shorter time. This makes it possible to prevent the load connected to the battery system 110 or the lines from being burned due to an accident current, and since the circuit is broken before the fuse connected to the battery system 110 is blown, it is possible to prevent the fuse from being blown.

[0037] FIG. 2 is a circuit diagram showing the structure of a battery protection device 200 in which a battery system and a line are connected by a semiconductor switch in this embodiment of the present invention.

[0038] As shown in FIG. 2, a battery protection device 200 according to an embodiment of the present invention includes a battery system 110 having a battery rack 111 in which a plurality of batteries or cells are stacked in the form of a rack, and a line (DC link + 190, DC link - 191) to which a load is connected is connected via a circuit breaker including a semiconductor switch, i.e., a solid-state circuit breaker (SSCB) 220.

[0039] Here, the positive terminal (+) and the negative terminal (-) of the battery system 110 are each connected to a semiconductor circuit breaker 220, the positive terminal (+) of the battery system 110 and the semiconductor circuit breaker 220 are connected via a first fuse 121, and the negative terminal (-) of the battery system 110 and the semiconductor circuit breaker 220 are connected via a second fuse 122.

[0040] The first fuse 121 and the second fuse 122 protect the battery system 110 by melting when an overcurrent flows in, and protect the battery system 111 in exceptional circumstances such as a failure or abnormal operation of the semiconductor circuit breaker 220.

[0041] On the other hand, the DC Link positive terminal (+) 190 and the DC Link negative terminal (-) 191 are each connected to a semiconductor circuit breaker 220. The DC Link positive terminal (+) 190 is connected to the positive terminal (+) of the battery system 110 via the semiconductor circuit breaker 220. Also, the DC Link negative terminal (-) 191 is connected to the negative terminal (-) of the battery system 110 via the semiconductor circuit breaker 220. The DC Link positive terminal (+) 190 and the semiconductor circuit breaker 220 are connected by a first shutoff switch 231, and the DC Link negative terminal (-) 191 and the semiconductor circuit breaker 220 are connected by a second shutoff switch 232.

[0042] The first cutoff switch 231 and the second cutoff switch 232 are switches that physically cut off the connection between the lines (DC link positive terminal (+) 190, DC link negative terminal (−) 191) and the semiconductor circuit breaker 220.

[0043] The first cut-off switch 231 and the second cut-off switch 232 are mechanical switches that require a relatively long time to cut off the circuit, but they physically cut off the connection between the line and the battery system 110.When an accident current is detected, a semiconductor switch section of the semiconductor circuit breaker 220, which has a high switching speed, primarily cuts off the electrical connection between the line and the battery system 110, and then secondarily cuts off the physical connection, thereby more safely protecting the battery system 110 and the load from burning.

[0044] Meanwhile, a rack battery management system (hereinafter referred to as RBMS) 210, which serves as a control unit of the battery protection device 200, manages switching between charge / discharge modes of the battery system 110 and performs voltage, current, temperature monitoring, etc. to protect the battery system 110.

[0045] Also, depending on the monitoring result, the RBMS 210 controls the semiconductor circuit breaker 220 to cut off the current output from the battery system 110 and the current flowing into the battery system 110. That is, the RBMS 210 controls the semiconductor circuit breaker 220 to detect the current flowing into the battery system 110 from the lines (DC link positive terminal (+) 190, DC link negative terminal (-) 191) and the current output from the battery system 110 to the lines, and determines whether or not a fault current has occurred based on the current detection result.

[0046] In addition, depending on the result of the determination, the semiconductor switch unit of the semiconductor circuit breaker 220 is controlled to cut off the electrical connection between the line and the battery system 110, and then the first cut-off switch 231 and the second cut-off switch 232 are controlled to physically isolate the battery system 110 from the line.

[0047] In addition, the RBMS 210 controls a fan switch 290 that turns on / off the operation of a BPU fan 292 for cooling the inside of the battery protection device 200 and a module fan 291 for cooling the battery system 110, and after the BPU fan 292 and the module fan 291 are driven, controls the rotation speed (e.g., RPM (Rotates Per Minute)) of the BPU fan 292 and the module fan 291.

[0048] In order to drive the RBMS 210, the battery protection device 200 according to an embodiment of the present invention is configured to receive power (e.g., SSCB / RBMS POWER 24V) for driving the RBMS 210 and the semiconductor circuit breaker 220 from an external power source, and to receive driving power (e.g., FAN POWER 24V) for driving the BPU fan 292 and the module fan 291 from the external power source.

[0049] Meanwhile, as described above, the RBMS 210 controls the overall operation of the semiconductor circuit breaker 220. Therefore, the RBMS 210 may be a controller of the semiconductor circuit breaker 220. In this case, the controller of the battery protection device 200 according to the embodiment of the present invention also functions as the controller of the semiconductor circuit breaker 220.

[0050] Hereinafter, with reference to FIG. 3, a structure of the battery protection device 200 according to an embodiment of the present invention in which the control unit of the battery protection device 200 functions as the control unit of the semiconductor circuit breaker 220 will be described.

[0051] As shown in FIG. 3, the semiconductor circuit breaker 220 according to an embodiment of the present invention is provided between the battery system 110 and the lines (DC link positive terminal (+) 190, DC link negative terminal (-) 191) that allows for turn on / turn off, and includes a semiconductor switch unit 310 having a first semiconductor switch 311 and a second semiconductor switch 312 connected in series with each other, a first shutoff switch 231 and a second shutoff switch 232, a first gate driver 341 and a second gate driver 342, an overvoltage suppression unit 330, a current sensor 350, and an RBMS 210.

[0052] Normally, when the battery is discharged, a current flows from the battery system 110 to the line. On the other hand, when the battery is charged, a current flows from the line to the battery system 110. Therefore, the semiconductor circuit breaker 220 is formed so as to be able to interrupt not only the current flow from the battery system 110 to the line, but also the current flow from the line to the battery system 110.

[0053] For such bidirectional blocking, the first semiconductor switch 311 and the second semiconductor switch 312 are arranged with their sources and drains in the opposite directions as shown in Fig. 3. Here, the first semiconductor switch 311 and the second semiconductor switch 312 are semiconductor switches formed of N-channel MOSFET elements.

[0054] The first semiconductor switch 311 and the second semiconductor switch 312 further include a first diode 321 and a second diode 322 arranged in the opposite direction to the current flow in order to prevent damage to the MOSFET elements due to a reverse voltage when a circuit is interrupted due to a fault current. In this case, the anode and cathode of the first diode 321 and the second diode 322 are connected to the source terminal and the drain terminal of the MOSFET elements 311 and 312, respectively.

[0055] Therefore, the first diode 321 is connected in parallel to the MOSFET element of the first semiconductor switch 311, and is arranged in the opposite direction to the current flowing from the positive terminal (+) of the battery system 110 to the DC link positive terminal (+) 190. In addition, the second diode 322 is connected in parallel to the MOSFET element of the second semiconductor switch 312, and is arranged in the opposite direction to the current flowing from the DC link positive terminal (+) 190 to the positive terminal (+) of the battery system 110.

[0056] As described above, the semiconductor circuit breaker 220 according to the embodiment of the present invention includes the first semiconductor switch 311 and the second semiconductor switch 312 configured in a complementary symmetrical form, and is configured to be able to interrupt all fault currents flowing in both directions.

[0057] Meanwhile, the overvoltage suppression unit 330 prevents an overvoltage from being generated across the semiconductor switch unit 310 due to a residual current when the semiconductor circuit breaker 220 breaks the circuit due to a fault current.

[0058] The overvoltage suppression unit 330 may include a snubber circuit or an element for suppressing an overvoltage, such as a TVS (Transient Voltage Suppressor) element. Alternatively, the overvoltage suppression unit 330 may include a free wheeling circuit formed of at least one diode and a resistor and connected to both ends of the semiconductor switch unit 310, respectively.

[0059] The current sensor 350 detects the magnitude of the current flowing into the semiconductor circuit breaker 220 or the current output through the semiconductor circuit breaker 220. When an overcurrent exceeding a predetermined magnitude is detected as a result of detecting the magnitude of the current, the current sensor 350 transmits a signal to the RBMS 210, which serves as a control unit of the semiconductor circuit breaker 220, to notify the occurrence of an overcurrent.

[0060] Meanwhile, the current sensor 350 may be disposed between the semiconductor switch unit 310 and the DC link positive terminal (+) 190 and may measure the magnitude of the output current of the battery system 110 output from the semiconductor switch unit 310 to a load through a line. Alternatively, the current sensor 350 may measure the magnitude of the input current flowing in from the DC link positive terminal (+) 190 for charging the battery system 110.

[0061] In addition, the current sensor 350 may be disposed not only between the semiconductor switch unit 310 and the DC link positive terminal (+) 190, but also between the negative terminal (-) of the battery system 110 (or the second fuse 122 connected to the negative terminal (-) of the battery system 110) and the DC link negative terminal (-) 191 in order to measure the magnitude of the output current and the input current.

[0062] Furthermore, the first gate driver 341 and the second gate driver 342 apply gate voltages to the gate terminals of the first semiconductor switch 311 and the second semiconductor switch 312 constituting the semiconductor switch unit 310 under the control of the RBMS 210. In this case, when a gate voltage exceeding the respective threshold voltages of the first semiconductor switch 311 and the second semiconductor switch 312 is applied, the resistance of the output end of the first semiconductor switch 311 and the second semiconductor switch 312 becomes smaller than the input end, so that the input end and the output end of the first semiconductor switch 311 and the second semiconductor switch 312 are conducted, and the positive end (+) of the battery system 110 and the DC link positive end (+) 190 are electrically connected.

[0063] In contrast, when the first gate driver 341 and the second gate driver 342 apply a gate voltage lower than a predetermined threshold voltage to the gate terminals of the first semiconductor switch 311 and the second semiconductor switch 312, or apply no gate voltage, the resistance of the output end of the first semiconductor switch 311 and the second semiconductor switch 312 is equal to or greater than the resistance of the input end.

[0064] As a result, the input terminals and output terminals of the first semiconductor switch 311 and the second semiconductor switch 312 are not conductive, and the positive terminal (+) of the battery system 110 and the DC link positive terminal (+) 190 are electrically separated (insulated) and the connection is cut off.

[0065] Meanwhile, the RBMS 210 controls the overall operation of the battery protection device 200 according to an embodiment of the present invention. For example, the RBMS 210 manages switching between charge / discharge modes of the battery system 110, controls the semiconductor circuit breaker 220, and electrically and physically connects the battery system 110 to a line.

[0066] More specifically, the RBMS 210 first controls the first cutoff switch 231 and the second cutoff switch 232 to physically connect the battery system 110 to the line (DC Link positive terminal (+) 190). Next, the RBMS 210 controls each of the gate drivers 341 and 342 to apply a voltage higher than a predetermined threshold voltage to the gate terminal of each of the semiconductor switches 311 and 312.

[0067] Then, the applied gate voltage reduces the resistance of the output terminal of each semiconductor switch 311, 312, so that the battery system 110 and the line (DC Link positive terminal (+) 190) are electrically connected by at least one of the semiconductor switches 311, 312.

[0068] When the battery system 110 and the line are thus physically and electrically connected, the RBMS 210 monitors the current using the current sensor 350 to protect the battery system 110.

[0069] Furthermore, if the monitoring result indicates that a fault current is output from the battery system 110 or that a fault current is flowing in from the line, the RBMS 210 controls each gate driver 341, 342 to apply a voltage lower than a predetermined threshold voltage to the gate terminal of each semiconductor switch 311, 312, or to not apply any gate voltage.

[0070] Then, the resistance of the output terminal of each of the semiconductor switches 311, 312 becomes greater than the resistance of the input terminal, and the battery system 110 and the line (DC Link positive terminal (+) 190) are electrically disconnected.

[0071] Furthermore, when the electrical connection between the battery system 110 and the line is cut off, the RBMS 210 controls the first cutoff switch 231 and the second cutoff switch 232 so that the battery system 110 and the line (DC Link positive terminal (+) 190) are physically separated. Therefore, when a fault current is detected as a result of the current monitoring, the battery system 110 and the line are electrically and physically cut off.

[0072] Meanwhile, the electrical disconnection is performed by adjusting the gate voltage applied to the gate terminals of the semiconductor switches 311 and 312. Therefore, when a fault current occurs, the connection between the battery system 110 and the line is disconnected in a very short time.

[0073] By doing this, the connection between the battery system 110 and the line is cut off before the fuses (first fuse 121, second fuse 122) located between the semiconductor circuit breaker 220 and the positive terminal (+) of the battery system 110, and between the semiconductor circuit breaker 220 and the negative terminal (-) of the battery system 110 are blown by the fault current.

[0074] Therefore, the first fuse 121 and the second fuse 122 are protected, and even if the connection between the battery system 110 and the line is cut off due to an accident current, the connection between the semiconductor circuit breaker 220 and the positive terminal (+) of the battery system 110, and the connection between the semiconductor circuit breaker 220 and the negative terminal (-) of the battery system 110 are maintained.

[0075] Therefore, when the accident in the line or battery system 110 is resolved and the current flowing between the battery system 110 and the line is restored, the RBMS 210 controls the gate drivers 341, 342, the first cut-off switch 231 and the second cut-off switch 232 of the semiconductor circuit breaker 220 to reconnect the battery system 111 to the line, thereby automatically restoring the connection between the battery system 111 and the line (DC Link positive terminal (+) 190, DC Link negative terminal (-) 191).

[0076] Meanwhile, the current sensor 350 is a giant magnetoresistance (GMR) sensor that uses a GMR element. The GMR sensor uses a phenomenon in which a magnetic resistance change of several tens of percent (about 70%) occurs in a multi-layered thin film structure composed of a ferromagnetic thin film and a non-magnetic metal thin film, and is smaller in size than a Hall sensor and can detect the magnitude of a current without contact, just like the Hall sensor.

[0077] On the other hand, the GMR sensor has a large magnetoresistance change rate, and therefore has the advantage of being able to significantly reduce the time required to detect an overcurrent. Figure 4 is a graph showing the overcurrent detection performance of the GMR sensor.

[0078] As shown in Figure 4, the time required for the GMR sensor to detect an overcurrent is 1.5, which is very short. As such, the GMR sensor has a much shorter time to detect an overcurrent, and therefore has better current detection performance than the Hall sensor. In addition, like the Hall sensor, the GMR sensor can measure current without contact, which has the advantage of reducing the effect of noise from the line.

[0079] Meanwhile, as described above, the battery protection device 200 according to the embodiment of the present invention can control the circuit connection between the battery system 110 and the line by using the semiconductor circuit breaker 220 including a power semiconductor such as a MOSFET instead of a conventional mechanical molded case circuit breaker such as an MCCB. Therefore, the control unit of the battery protection device 200 according to the embodiment of the present invention, i.e., the RBMS 210, can perform the function of controlling the semiconductor circuit breaker 220.

[0080] FIG. 5 is a flowchart showing an operation process in which the RBMS 210 provided in the battery protection device according to an embodiment of the present invention controls the semiconductor circuit breaker 220. As shown in FIG.

[0081] As shown in FIG. 5, the RBMS 210 according to the embodiment of the present invention drives the battery system 110 in a discharge mode or a charge mode by driving a power conversion system (PCS) or the like.

[0082] Then, the RBMS 210 first controls the first cutoff switch 231 and the second cutoff switch 232 to physically connect the battery system 110 to the lines (DC link positive terminal (+) 190, DC link negative terminal (-) 191) (S500).

[0083] Next, at least one of the first gate driver 341 and the second gate driver 342 is controlled so that a gate voltage equal to or higher than a predetermined threshold voltage is applied to the gate terminal of at least one of the first semiconductor switch 311 and the second semiconductor switch 312 (S502).

[0084] In this way, the battery system 110 and the lines (DC link positive terminal (+) 190, DC link negative terminal (-) 191) are connected not only physically but also electrically, so that the current output from the battery system 110 is supplied to a load via the lines (when operating in discharge mode), or the current flowing in via the lines is input to the battery system 110, thereby charging the batteries that form the battery rack 111 (when operating in charge mode).

[0085] Meanwhile, when the battery system 110 and the line are connected in steps S500 and S502, the RBMS 210 detects via the current sensor 350 whether an overcurrent exceeding a predetermined rated current magnitude is output from the battery system 110, or whether an overcurrent exceeding the rated current magnitude is input from the line.

[0086] That is, the RBMS 210 detects, by the current sensor 350, whether or not the current flowing between the currently connected battery system 110 and the line is an overcurrent (S504).

[0087] If no overcurrent is detected as a result of the detection, the RBMS 210 maintains the current state in which the battery system 110 and the line are connected, and maintains the state in which an overcurrent is detected.

[0088] On the other hand, when an overcurrent is detected, the RBMS 210 controls at least one of the first gate driver 341 and the second gate driver 342 to apply a gate voltage less than a predetermined threshold voltage to at least one gate terminal of the first semiconductor switch 311 and the second semiconductor switch 312, or to apply no gate voltage (S506).

[0089] Here, the RBMS 210 may control both the first gate driver 341 and the second gate driver 342 to apply a gate voltage less than the threshold voltage, or to apply no gate voltage.

[0090] Alternatively, the RBMS 210 may control only one of the first gate driver 341 and the second gate driver 342 to apply a gate voltage lower than the threshold voltage or to not apply any gate voltage depending on the current driving mode of the battery protection device 200.

[0091] For example, when the battery protection device 200 is currently operating in the discharge mode, the RBMS 210 controls only the first gate driver 341. Here, a gate voltage equal to or higher than the threshold voltage is still applied to the gate terminal of the second semiconductor switch 312, so that the input terminal and the output terminal of the second semiconductor switch 312 are maintained in an electrically conductive state.

[0092] In contrast, a gate voltage less than the threshold voltage or no gate voltage is applied to the gate terminal of the first semiconductor switch 311, so that the input end and the output end of the first semiconductor switch 311 are electrically insulated.

[0093] On the other hand, a first diode 321 is arranged between the source terminal and drain terminal of the first semiconductor switch 311 in the direction opposite to the current flow from the positive terminal (+) of the battery system 110 to the DC Link positive terminal (+) 190.

[0094] This prevents current from flowing from the drain terminal to the source terminal of the first semiconductor switch 311 when the circuit is interrupted. This electrically insulates the positive terminal (+) of the battery system 110 and the DC Link positive terminal (+) 190.

[0095] Meanwhile, when the battery protection device 200 is currently operating in the charging mode, the RBMS 210 controls only the second gate driver 342. Here, a gate voltage equal to or higher than the threshold voltage is still applied to the gate terminal of the first semiconductor switch 311, so that the input terminal and the output terminal of the first semiconductor switch 311 are maintained in an electrically conductive state.

[0096] In contrast, a gate voltage less than the threshold voltage or no gate voltage is applied to the gate terminal of the second semiconductor switch 312, so that the input end and the output end of the second semiconductor switch 312 are electrically insulated.

[0097] On the other hand, a second diode 322 is arranged between the source terminal and drain terminal of the second semiconductor switch 312 in the direction opposite to the current flow from the DC Link positive terminal (+) 190 to the positive terminal (+) of the battery system 110.

[0098] This prevents current from flowing from the drain terminal to the source terminal of the second semiconductor switch 312 when the circuit is interrupted. This electrically insulates the DC Link positive terminal (+) 190 and the positive terminal (+) of the battery system 110.

[0099] On the other hand, when at least one gate driver is controlled in step S506 and the battery system 110 and the line are electrically isolated, the RBMS 210 controls the first cutoff switch 231 and the second cutoff switch 232 to physically isolate the positive terminal (+) of the battery system 110 from the DC link positive terminal (+) 190, and the negative terminal (-) of the battery system 110 from the DC link negative terminal (-) 191 (S508).

[0100] In this way, even if an overcurrent, i.e., a fault current, occurs from the battery system 110 or the line, the semiconductor circuit breaker 220 can electrically and physically disconnect the battery system 110 from the line under the control of the RBMS 210.

[0101] The present invention described above can be realized as a computer readable code on a program recording medium. The computer readable medium includes any kind of storage device on which data readable by a computer system is recorded. The computer readable medium includes a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and also includes those realized in the form of a carrier wave (e.g., transmission over the Internet).

[0102] Therefore, the above detailed description should not be construed as limiting in any respect, but should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the claims, and all modifications within the scope of the equivalents of the present invention are included in the present invention.

Claims

1. In the Battery Protection Unit (BPU) that connects the battery system to the line, A semiconductor circuit breaker is disposed between the battery system and a line, and has a semiconductor switch that electrically connects or isolates the battery system and the line in response to a gate voltage applied to a gate terminal. A cutoff switch that physically connects or disconnects the semiconductor circuit breaker and a line; a rack battery management system (RBMS) that, when the battery system is connected to the line, controls a gate driver that applies the gate voltage in response to a result of detecting a current flowing between the battery system and the line, thereby isolating the battery system from the line, and also controls the cutoff switch to physically separate the semiconductor circuit breaker from the line; The semiconductor circuit breaker comprises: A plurality of semiconductor switches connected in series, A resistor is connected to both ends of the plurality of semiconductor switches connected in series, an overvoltage suppression unit that prevents an overvoltage generated across the plurality of semiconductor switches when the line and the battery system are insulated by at least one of the plurality of semiconductor switches; The battery protection device, wherein the overvoltage suppression unit includes a TVS (Transient Voltage Suppressor) element.

2. The semiconductor circuit breaker comprises: a first semiconductor switch having a source terminal and a drain terminal arranged to allow a current flow from the battery system to the rail; a second semiconductor switch connected in series with the first semiconductor switch, the second semiconductor switch having a source terminal and a drain terminal arranged to form a current flow from the line to the battery system; a first gate driver that applies a gate voltage to a gate terminal of the first semiconductor switch under control of the rack battery management system; a second gate driver that applies a gate voltage to a gate terminal of the second semiconductor switch under control of the rack battery management system; The rack battery management system includes:

2. The battery protection device according to claim 1, wherein when the battery system is physically connected to the line via the semiconductor circuit breaker, at least one of the first and second gate drivers is controlled to apply a gate voltage having a predetermined voltage, thereby electrically connecting the battery system to the line.

3. The rack battery management system includes: Controlling the battery system to operate in either a discharge mode in which a current is output from the battery system or a charge mode in which a current is supplied from the line to the battery system; controlling either the first or second gate driver in response to the current detection result so as to apply a gate voltage less than the predetermined voltage; Any one of the gate drivers whose gate voltage is controlled in response to the current detection result, 3. The battery protection device according to claim 2, wherein the protection voltage varies depending on an operation mode of the battery system.

4. The rack battery management system includes: If the battery system is in a discharging mode, controlling the first gate driver to apply a gate voltage less than the predetermined voltage; 4. The battery protection device according to claim 3, wherein the second gate driver is controlled to apply a gate voltage less than the predetermined voltage when the battery system is in a charging mode.

5. The first and second semiconductor switches are The device is an N-channel MOSFET in which the source terminal and the drain terminal are arranged in opposite directions to each other, 3. The battery protection device according to claim 2, further comprising a diode arranged in a direction opposite to the current flow of the N-channel MOSFET devices.

6. The semiconductor circuit breaker comprises: a current sensor that detects a current flowing between the battery system and a line; The current sensor is 2. The battery protection device according to claim 1, wherein the sensor is a giant magnetoresistance (GMR) sensor.

7. 2. The battery protection device according to claim 1, wherein a positive terminal (+) and a negative terminal (-) of the battery system are connected to the semiconductor switch via fuses, respectively.

8. The predetermined voltage is 3. The battery protection device according to claim 2, wherein the threshold voltage is a threshold voltage that connects the input terminal and the output terminal of the first semiconductor switch or the second semiconductor switch.

9. A method for controlling a battery protection unit (BPU) including a semiconductor circuit breaker that connects a battery system and a line, comprising: A rack battery management system (RBMS) of the battery protection device controls a cutoff switch disposed between the semiconductor circuit breaker and a line, and physically connects the battery system and the line; The rack battery management system controls at least one of a plurality of semiconductor switches included in the semiconductor circuit breaker to electrically connect the battery system and the line; The rack battery management system detects an overcurrent of a predetermined magnitude or more from a current flowing between the battery system and a line; The rack battery management system controls a gate driver that applies a gate voltage to at least one of the plurality of semiconductor switches according to a result of the detection, thereby isolating the battery system from a line; the rack battery management system controls the disconnect switch to physically isolate the solid-state circuit breaker from the line; The semiconductor circuit breaker comprises: an overvoltage suppression unit connected to both ends of the plurality of semiconductor switches; The step of insulating the battery system from the line includes: When the line and the battery system are insulated from each other, the overvoltage suppression unit prevents an overvoltage generated across the semiconductor switches due to the insulation, The control method for a battery protection device, wherein the overvoltage suppression unit includes a TVS (Transient Voltage Suppressor) element.

10. The semiconductor circuit breaker comprises: a first semiconductor switch having a source terminal and a drain terminal arranged to allow a current flow from the battery system to the rail; a second semiconductor switch connected in series with the first semiconductor switch, the second semiconductor switch having a source terminal and a drain terminal arranged to form a current flow from the line to the battery system; a first gate driver that applies a gate voltage to a gate terminal of the first semiconductor switch under control of the rack battery management system; The method for controlling a battery protection device according to claim 9, further comprising: a second gate driver for applying a gate voltage to a gate terminal of the second semiconductor switch under the control of the rack battery management system.

11. The step of electrically connecting the battery system and the line includes: operating the battery system in either a discharging mode or a charging mode; 11. The method of claim 10, further comprising: controlling at least one of the first and second gate drivers to apply a gate voltage equal to or higher than a predetermined threshold voltage according to an operation mode of the battery system.

12. The step of controlling the gate driver and isolating the battery system from the line includes:

12. The method of claim 11, further comprising the step of controlling different gate drivers to apply gate voltages less than a predetermined threshold voltage according to an operation mode of the battery system.

13. The step of controlling different gate drivers according to an operation mode of the battery system includes: controlling the first gate driver to apply a gate voltage less than the threshold voltage when the battery system operates in a discharge mode; 13. The method of claim 12, further comprising controlling the second gate driver to apply a gate voltage less than the threshold voltage when the battery system is operated in a charging mode.

14. The step of controlling the gate driver and isolating the battery system from the line includes:

11. The method of claim 10, further comprising the step of controlling both the first gate driver and the second gate driver to apply a gate voltage less than a predetermined threshold voltage.

15. The semiconductor circuit breaker comprises: The current sensor includes a Giant MagnetoResistance (GMR) sensor, The step of detecting an overcurrent includes:

10. The method for controlling a battery protection device according to claim 9, further comprising the step of detecting the overcurrent from a current flowing between the battery system and a line by the GMR sensor.

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