Wake-up circuit and battery system including same

Abstract

The battery system may include a battery pack including a plurality of battery cells, a battery management system that monitors and manages the battery pack, a power source for supplying a voltage to the battery management system, and a wake-up circuit coupled to a first CAN bus line and a second CAN bus line, the wake-up circuit connecting the power source to the battery management system when a CAN bus voltage difference, which is a voltage difference between a first voltage of the first CAN bus line and a second voltage of the second CAN bus line, is equal to or greater than a predetermined threshold level.

Description

[Technical field]

[0001] Cross-references to related applications (etc.) This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0083198 dated July 6, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present disclosure relates to a wake-up circuit and a battery system including the same. [Background technology]

[0003] To wake up the battery system, the transceiver and main control unit of the battery system and the external system that controls the battery system must operate. In the sleep mode, the battery system does not perform charging or discharging operations, but performs a wake-up operation in a standby state according to a wake-up signal received from an external system. Although the amount of standby power consumed by the battery system in a standby state is small, if the standby time is long, the amount of standby power increases, making it difficult to maintain the battery system in the slip mode for a long period of time. Especially in seasons or areas with low temperatures, it is difficult to manage the battery system in the slip mode for a long period of time. Therefore, it is necessary to reduce the standby power of the battery system in the slip mode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent No. 10-1457986 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a wake-up circuit capable of reducing standby power in a sleep mode and a battery system including the same. [Means for solving the problem]

[0006] According to one aspect of the present invention, a wake-up circuit for controlling a connection between a power source and a battery management system includes an optocoupler including a photodiode connected between a first CAN bus line and a second CAN bus line, and a phototransistor turned on by light emission from the photodiode, a control transistor turned on when the phototransistor is turned on, and a power transistor turned on when the control transistor is turned on and connecting the power source and the battery management system, and the photodiode can be turned on and emit light when a CAN bus voltage difference, which is a voltage difference between a first voltage of the first CAN bus line and a second voltage of the second CAN bus line, is equal to or greater than a predetermined threshold level.

[0007] The wake-up circuit may further include a relay connected between the photodiode and one of the first CAN bus line and the second CAN bus line, the relay being opened under the control of the battery management system after the CAN bus voltage difference is less than the predetermined threshold level.

[0008] The wake-up circuit may further include a low-pass filter connected between the first CAN bus line and the second CAN bus line, and the CAN bus voltage difference may be transferred to the photodiode through the low-pass filter.

[0009] The power source may be connected to one end of the phototransistor, and the other end of the phototransistor may be connected to a control end of the control transistor.

[0010] The wake-up circuit may further include a low-pass filter coupled between the other end of the phototransistor and the control end of the control transistor.

[0011] The wake-up circuit may further include a resistor connected between a control end and one end of the control transistor, the other end of the control transistor being connected to the gate of the power transistor.

[0012] One end of the power transistor may be coupled to the power source, the other end of the power transistor may be coupled to the battery management system, and a gate of the power transistor may be coupled to one end of the control transistor.

[0013] According to another aspect of the invention, a battery system may include a battery pack including a plurality of battery cells, a battery management system that monitors and manages the battery pack, a power source for supplying a voltage to the battery management system, and a wake-up circuit coupled to a first CAN bus line and a second CAN bus line, the wake-up circuit connecting the power source to the battery management system when a CAN bus voltage difference, which is a voltage difference between a first voltage of the first CAN bus line and a second voltage of the second CAN bus line, is equal to or greater than a predetermined threshold level.

[0014] The wake-up circuit may include an optocoupler connected between the first CAN bus line and the second CAN bus line, the optocoupler including a photodiode that is turned on and emits light when the CAN bus voltage difference is equal to or greater than a predetermined threshold level, and a phototransistor that is turned on by the light emitted by the photodiode, a control transistor that is turned on when the phototransistor is turned on, and a power transistor that is turned on when the control transistor is turned on and connects the power source and the battery management system.

[0015] The wake-up circuit may further include a relay connected between the photodiode and one of the first CAN bus line and the second CAN bus line, the relay being opened under the control of the battery management system after the CAN bus voltage difference is less than the predetermined threshold level.

[0016] The wake-up circuit may further include a low-pass filter connected between the first CAN bus line and the second CAN bus line, and the CAN bus voltage difference may be transferred to the photodiode through the low-pass filter.

[0017] The power source may be connected to one end of the phototransistor, and the other end of the phototransistor may be connected to a control end of the control transistor.

[0018] The wake-up circuit may further include a low-pass filter coupled between the other end of the phototransistor and the control end of the control transistor.

[0019] The wake-up circuit may further include a resistor connected between a control end and one end of the control transistor, the other end of the control transistor being connected to the gate of the power transistor.

[0020] One end of the power transistor may be coupled to the power source, the other end of the power transistor may be coupled to the battery management system, and a gate of the power transistor may be coupled to one end of the control transistor. Effect of the Invention

[0021] A wake-up circuit capable of reducing standby power consumption in a sleep mode and a battery system including the same are provided. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of a battery system according to one embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a wake-up circuit according to an embodiment. [Diagram 3] FIG. 3 is a diagram illustrating a portion of a wake-up circuit according to an embodiment. [Figure 4] FIG. 4 is a waveform diagram illustrating two CAN bus voltages, a wake-up holding signal, and a relay opening signal according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The suffixes "module" and / or "section" for components used in the following description are given or mixed for the sake of ease of description, and do not have any distinct meaning or role. In addition, the terms "section", "section", "module" and the like described in the specification refer to a unit that processes at least one function or operation, and may be realized by hardware, software, or a combination of hardware and software.

[0024] In addition, when describing the embodiments disclosed herein, if it is determined that a detailed description of related publicly known technology may obscure the gist of the embodiments disclosed herein, the detailed description will be omitted. In addition, the attached drawings are merely for the purpose of making the embodiments disclosed herein easier to understand, and the technical ideas disclosed herein are not limited by the attached drawings, and should be understood to include all modifications, equivalents, or alternatives included in the ideas and technical scope of the present invention.

[0025] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0026] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that it may be directly coupled or connected to the other component, but that there may be other components in between. In contrast, when a component is referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0027] In this application, terms such as "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof set forth in the specification, but should be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] FIG. 1 is a schematic diagram of a battery system according to one embodiment.

[0029] In FIG. 1, the battery system 100 is connected to a power conversion system (PSC) 200. The power conversion system 200 may receive energy from the battery system 100 and supply power to an electrical load, or may convert energy supplied from the outside to charge the battery system 100. A power management system (PMS) 300 may control a power conversion operation by the power conversion system 200. For example, the power conversion operation controlled by the power management system 300 may include a power conversion operation in which the power conversion system 200 converts and outputs energy supplied from the battery system 100, or a power conversion operation in which the power conversion system 200 converts and supplies energy input to the power conversion system 200 to the battery system 100. To this end, the power management system 300 may be connected to both ends P+ and P- of the battery system 100, and may transmit a signal for controlling the power conversion operation in the power conversion system 200. In addition, the power management system 300 may receive feedback information required for controlling the power conversion operation from the power conversion system 200. The battery system 100 may be an ESS (Energy Storage System).

[0030] As shown in FIG. 1, the battery system 100, the power conversion system 200, and the power management system 300 can transmit and receive information required for control through CAN communication. To realize the CAN communication, each system includes a CAN transceiver, and each CAN transceiver is connected to two CAN buses CAN_H and CAN_L. The battery system 100 includes a CAN transceiver 30, and the CAN transceiver 30 can transmit and receive digital data to and from a battery management system (BMS) 20. The power conversion system 200 transmits and receives digital data to and from a CAN transceiver 210, and the power management system 300 transmits and receives digital data to and from a CAN transceiver 310. Each CAN transceiver 30, 210, and 310 can convert digital data received from a connected system into two voltages that are differential signals and transmit the converted data to each of the two CAN buses CAN_H and CAN_L, and can generate digital data based on the difference between the two voltages received from the two CAN buses CAN_H and CAN_L and transmit the generated digital data to a corresponding system. Specifically, each CAN transceiver detects the voltage difference between two CAN buses CAN_H and CAN_L, converts the detected voltage difference into digital data, and identifies the contents of a message using an identifier in the converted digital data to receive corresponding information. Each CAN transceiver can transmit two voltages converted into digital data to the two CAN buses CAN_H and CAN_L in the order of the assigned ID.

[0031] 1, the battery system 100, the power conversion system 200, and the CAN communication between the power conversion system 200 through the CAN network are merely examples for explaining the invention, and the invention is not limited thereto. The present invention can be applied to various CAN communication methods using two CAN buses that transmit two voltages, which are known differential signals.

[0032] The battery system 100 includes a battery pack 10, a battery management system 20, a CAN transceiver 30, a wake-up circuit 40, and a power supply 50.

[0033] The battery pack 10 shown in FIG. 1 includes a number of battery cells 10_1-10_n (n is a natural number of 2 or more) connected in series. Although the battery pack 10 is shown in FIG. 1 as including n battery cells 10_1-10_n connected in series, this is an example and the invention is not limited thereto. For example, a number of battery cells may be connected in series in units of two or more parallel-connected battery cells. Alternatively, a number of battery cells may be connected in parallel in units of a number of serially-connected battery cells. Both ends P+ and P- of the battery pack 10 are connected to the power conversion system 200, and energy may be supplied from the battery pack 10 to the power conversion system 200 through both ends P+ and P-, or energy may be supplied from the power conversion system 200 to the battery pack 10.

[0034] The battery management system 20 is connected to the plurality of battery cells 10_1-10_n, and can sense the cell voltages of the plurality of battery cells 10_1-10_4, the battery current, the temperature, etc. of the battery pack 10, control the charge / discharge current of the battery pack 10 based on the sensed information, and control a cell balancing operation for the plurality of battery cells 10_1-10_4. When the battery management system 20 is woken up, it can perform a control operation for connection to the power source 50 through the wake-up circuit 40. For this purpose, the battery management system 20 can generate a wake-up holding signal HS and a relay opening signal RO.

[0035] The CAN transceiver 30 can convert the digital data received from the battery management system 20 into two voltages that are differential signals and transmit them to each of the two CAN buses, CAN_H and CAN_L. The CAN transceiver 30 can convert the voltage difference between the two voltages received from the two CAN buses, CAN_H and CAN_L, into digital data, and if the converted digital data is a message that the battery management system 20 should receive, the message can be transmitted to the battery management system 20.

[0036] The power supply 50 can supply power for waking up the battery management system 20. The power supply 50 is connected to the battery pack 10 and can generate a power supply voltage at a certain level using the voltage of the battery pack 10. Alternatively, the power supply 50 can generate a power supply voltage at a certain level using the voltage from a separate battery that is distinct from the battery pack 10.

[0037] When the voltage difference between the two voltages received from the two CAN buses, CAN_H and CAN_L, indicates waking up the battery management system 20, the wake-up circuit 40 can connect the battery management system 20 to the power supply 50.

[0038] Hereinafter, the wake-up circuit 40 will be described with reference to FIG. 2.

[0039] FIG. 2 is a diagram showing a wake-up circuit according to an embodiment.

[0040] The wake-up circuit 40 includes a control transistor 41, a power transistor 42, and an optocoupler 43. A wake-up signal is transmitted to the control transistor 41 through the optocoupler 43, and the control transistor 41 is turned on by the wake-up signal. When the control transistor 41 is turned on, the power transistor 42 is turned on, and the power supply 50 is connected to the battery management system 20. The battery management system 20 wakes up by the power supply voltage supplied from the power supply 50.

[0041] The optocoupler 43 includes a photodiode PD and a phototransistor PT. The anode of the photodiode PD is connected to the contact N1, and the cathode of the photodiode PD is connected to the contact N2. The capacitor C1 is connected between the contact N1 and the contact N2, and the resistor R1 is connected between the CAN bus CAN_H and the contact N1. One end of the resistor R1 is connected to the CAN bus CAN_H at the contact N_H, and the other end of the resistor R1 is connected to the contact N1. The relay 44 is connected between the contact N2 and the contact N_L. One end of the relay 44 is connected to the CAN bus CAN_L at the contact N_L, and the other end of the relay 44 is connected to the contact N2. The relay 44 includes an inductor 45 and a switch 46, and the switch 46 is basically in a closed state and can be opened when a current flows through the inductor 45.

[0042] The resistor R1 and the capacitor C1 may constitute a low-pass filter, and a voltage difference between the voltages of the CAN buses CAN_H and CAN_L (hereinafter, CAN bus voltage difference) may be transmitted to the photodiode PD through the low-pass filter. The low-pass filter including the resistor R1 and the capacitor C1 is connected in parallel to the photodiode PD. The CAN bus voltage difference may be equal to or greater than a predetermined voltage to wake up the battery management system 20. For example, the power management system 300 may transmit a relatively high predetermined voltage to the CAN bus CAN_H and a relatively low predetermined voltage to the CAN bus CAN_L through the CAN transceiver 310. At this time, the CAN bus voltage difference may be equal to or greater than a level (threshold level) that can turn on the photodiode PD. The photodiode PD is turned on by the CAN bus voltage difference, and a current flows through the photodiode PD, causing the photodiode PD to emit light. When the photodiode PD emits light, the phototransistor PT may be turned on. The phototransistor PT may be maintained in an on state during a period during which the photodiode PD emits light, and the photodiode PD may emit light during a period during which the CAN bus voltage difference is equal to or greater than a threshold level.

[0043] The collector of the phototransistor PT is connected to the power supply 50, and the emitter of the phototransistor PT is connected to the base, which is the control end, of the control transistor 41. The control transistor 41 is realized as an npn BJT. The resistor R2 is connected between the emitter of the phototransistor PT and the base of the control transistor 41, and the capacitor C2 is connected between the base of the control transistor 41 and ground. The resistor R2 and the capacitor C2 can form a low-pass filter. The collector of the control transistor 41 is connected to the gate, which is the control end, of the power transistor 42, and the emitter of the control transistor 41 is connected to ground. The resistor R3 is connected between the base and emitter of the control transistor 41, and can maintain a voltage difference between the base and the emitter. The source of the power transistor 42 is connected to the power supply 50, and the drain of the power transistor 42 is connected to the battery management system 20.

[0044] During the on-period of the phototransistor PT, the control transistor 41 is turned on, and the gate of the power transistor 42 is connected to the ground through the control transistor 41 in the on-state, thereby turning on the power transistor 42. When the power transistor 42 is turned on, the voltage of the power source 50 can be supplied to the battery management system 20.

[0045] The relay 44 is opened when the switch 47 is turned on. Specifically, the switch 46 is connected between the contact N2 and the contact N_L, a voltage VDC is supplied to one end of the inductor 45, the other end of the inductor 45 is connected to one end of the switch 47, and the other end of the switch 47 is connected to the ground. The switch 47 is turned on by the on level of the relay opening signal RO, and when the switch 47 is turned on, a current flows through the inductor 45, and the switch 46 can be opened.

[0046] The wake-up holding signal HS can be supplied to the base of the control transistor 41. During the period in which the wake-up holding signal HS is at an on level, the control transistor 41 can be maintained in an on state.

[0047] 2, relay 44 is shown coupled between contacts N2 and N_L, but the invention is not so limited, and the relay may be coupled between contacts N1 and N_H.

[0048] FIG. 3 is a diagram illustrating a portion of a wake-up circuit according to an embodiment.

[0049] As shown in Fig. 3, the relay 51 is connected between the contact N1 and the contact N_H. The relay 51 includes a switch 52 and an inductor 53. The switch 52 is connected between the contact N1 and the contact N_H, and one end of the inductor 53 is supplied with a voltage VDC and the other end of the inductor 53 is connected to one end of a switch 54, the other end of which is connected to ground. The switch 54 is turned on at a turn-on level in accordance with a relay opening signal RO. When the switch 47 is turned on, a current flows through the inductor 53, and the switch 52 can be opened.

[0050] The wake-up operation will now be described with reference to FIG.

[0051] FIG. 4 is a waveform diagram illustrating two CAN bus voltages, a wake-up holding signal, and a relay opening signal according to one embodiment.

[0052] As shown in FIG. 4, at time T1, the first voltage V_H of the CAN bus CAN_H rises and the second voltage V_L of the CAN bus CAN_L falls. For example, the first voltage V_H rises from voltage V3 to voltage V4, and the second voltage V_L falls from voltage V2 to voltage V1. The voltages V2 and V3 may be at the same level. When the CAN bus voltage difference between the first voltage V_H and the second voltage V_L is equal to or greater than the threshold level, the photodiode PD emits light and the phototransistor PT is turned on. Then, as described above, the power transistor 42 is turned on and the power source 50 supplies a voltage to the battery management system 20. The battery management system 20 is woken up by the voltage supplied from the power source 50, and after waking up, it can perform necessary operations such as monitoring the battery pack 10. In addition, the battery management system 20 generates a wake-up holding signal HS at an on level at time T2. The time point T2 shown in FIG. 4 may be any time point during the period after the battery management system 20 is woken up until time point T3.

[0053] At time T3, the first voltage V_H drops and the second voltage V_L rises. For example, the first voltage V_H drops from voltage V4 to voltage V3, and the second voltage V_L rises from voltage V1 to voltage V2. Then, the CAN bus voltage difference between the first voltage V_H and the second voltage V_L becomes less than the threshold level, and the photodiode PD is turned off and does not emit light. This also turns off the phototransistor PT. Since the wake-up holding signal HS is applied to the base of the control transistor 41 at an ON level, the power transistor 42 is maintained in an ON state. The battery management system 20 can maintain the wake-up holding signal HS at an ON level from when it is woken up until time T5 when it completes a required operation.

[0054] The battery management system 20 generates a relay open signal RO at an ON level at time T4. The relay open signal RO at an ON level opens the relay 44. Therefore, after time T4, the wake-up circuit 40 does not affect the voltage transmitted through the CAN bus CAN_H and the CAN bus CAN_L. Time T4 may be any time after time T3.

[0055] 4, the hatched portions of the first voltage V_H and the second voltage V_L indicate that the voltage levels transmitted through the CAN buses CAN_H and CAN_L after wake-up are not limited. The first voltage V_H and the second voltage V_L after wake-up may vary depending on the voltages transmitted by any CAN transceiver to the CAN buses CAN_H and CAN_L.

[0056] In the past, a battery management system performed selective wake-up based on a lower block message on a protocol while maintaining an inactive state in a low power mode. However, the wake-up method according to the present invention can wake up based on the difference between the voltages transmitted through two CAN buses without having to maintain a low power mode. Therefore, the battery management system according to the present invention can wait for a long time in a sleep mode.

[0057] 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 those skilled in the art using the basic concept of the present invention defined in the following claims also belong to the scope of the present invention.

Claims

1. A wake-up circuit for controlling a connection between a power source and a battery management system, an optocoupler including a photodiode connected between a first CAN bus line and a second CAN bus line, and a phototransistor turned on by light emission of the photodiode; a control transistor that is turned on when the phototransistor is turned on; a power transistor that is turned on when the control transistor is turned on and connects the power source and the battery management system; The photodiode is and turning on and emitting light when a CAN bus voltage difference, which is a voltage difference between a first voltage of the first CAN bus line and a second voltage of the second CAN bus line, is equal to or greater than a predetermined threshold level. Wake-up circuit.

2. a relay connected between the photodiode and one of the first CAN bus line and the second CAN bus line, the relay being opened under the control of the battery management system after the CAN bus voltage difference is less than the predetermined threshold level.

2. The wake-up circuit according to claim 1.

3. a low pass filter connected between the first CAN bus line and the second CAN bus line, the CAN bus voltage difference is transmitted to the photodiode through the low pass filter; 3. The wake-up circuit according to claim 2.

4. The power source is connected to one end of the phototransistor, and the other end of the phototransistor is connected to a control end of the control transistor.

2. The wake-up circuit according to claim 1.

5. and a low-pass filter connected between the other end of the phototransistor and the control end of the control transistor.

5. The wake-up circuit according to claim 4.

6. The control transistor further includes a resistor connected between a control end and one end of the control transistor, The other end of the control transistor is coupled to the gate of the power transistor.

6. The wake-up circuit according to claim 5.

7. one end of the power transistor is coupled to the power source, the other end of the power transistor is coupled to the battery management system, and a gate of the power transistor is coupled to one end of the control transistor; 2. The wake-up circuit according to claim 1.

8. a battery pack including a plurality of battery cells; a battery management system that monitors and manages the battery pack; a power source for supplying a voltage to the battery management system; a wake-up circuit coupled to a first CAN bus line and a second CAN bus line, the wake-up circuit coupling the power source and the battery management system when a CAN bus voltage difference, the voltage difference between a first voltage of the first CAN bus line and a second voltage of the second CAN bus line, is equal to or greater than a predetermined threshold level. Battery system.

9. The wake-up circuit includes: an optocoupler including a photodiode connected between the first CAN bus line and the second CAN bus line, the photodiode being turned on and emitting light when the CAN bus voltage difference is equal to or greater than a predetermined threshold level, and a phototransistor being turned on by the light emitted by the photodiode; a control transistor that is turned on when the phototransistor is turned on; a power transistor that is turned on when the control transistor is turned on and that couples the power source and the battery management system; The battery system of claim 8.

10. The wake-up circuit includes: a relay connected between the photodiode and one of the first CAN bus line and the second CAN bus line, the relay being opened under the control of the battery management system after the CAN bus voltage difference is less than the predetermined threshold level.

10. The battery system of claim 9.

11. The wake-up circuit includes: a low pass filter connected between the first CAN bus line and the second CAN bus line, the CAN bus voltage difference is transmitted to the photodiode through the low pass filter; The battery system of claim 10.

12. The power source is connected to one end of the phototransistor, and the other end of the phototransistor is connected to a control end of the control transistor.

10. The battery system of claim 9.

13. The wake-up circuit includes: and a low-pass filter connected between the other end of the phototransistor and the control end of the control transistor.

13. The battery system of claim 12.

14. The wake-up circuit includes: The control transistor further includes a resistor connected between a control end and one end of the control transistor, The other end of the control transistor is coupled to the gate of the power transistor.

14. The battery system of claim 13.

15. one end of the power transistor is coupled to the power source, the other end of the power transistor is coupled to the battery management system, and a gate of the power transistor is coupled to one end of the control transistor; 10. The battery system of claim 9.

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