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-citation with 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 sleep mode, the battery system does not charge or discharge, but wakes up in response to a wake-up signal received from the external system in standby mode. While the amount of standby power consumed by the battery system in standby mode is small, the longer the standby time, the greater the standby power consumption, making it difficult to maintain the battery system in sleep mode for a long period of time. This is especially true in cold seasons or regions. Therefore, it is necessary to reduce the standby power of the battery system in sleep 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] SUMMARY OF THE INVENTION An object of the present invention is to provide a wake-up circuit capable of reducing standby power consumption 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: a photodiode connected between a first CAN bus line and a second CAN bus line; an optocoupler including a phototransistor that is turned on by 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, wherein the photodiode is turned on to 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 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 connected 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 terminal 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 voltage to the battery management system, and a wake-up circuit connected 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 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 connected 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 terminal 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. [Effects 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 explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating a battery system according to one embodiment. [Figure 2] FIG. 2 is a diagram illustrating a wake-up circuit according to an embodiment. [Figure 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 INVENTION

[0023] The suffixes "module" and / or "section" for components used in the following description are given or used interchangeably solely for the convenience of writing the specification, and do not have any distinct meanings or roles. Furthermore, terms such as "section," "section," and "module" used in the specification refer to a unit that processes at least one function or operation, and can be realized by hardware, software, or a combination of hardware and software.

[0024] Furthermore, 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. Furthermore, the attached drawings are intended only to facilitate understanding of the embodiments disclosed herein, and should not be construed as limiting the technical ideas disclosed herein, and should be understood to include all modifications, equivalents, or alternatives within the spirit 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 said to be "coupled" or "connected" to another component, it should be understood that it can be directly coupled or connected to the other component, but that there can be other components in between. Conversely, when a component is said to be "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0027] In this application, the terms "comprise" or "have" and the like are to be understood as specifying the presence of any feature, number, step, operation, component, part, or combination thereof stated in the specification, but without precluding the possible presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] FIG. 1 is a diagram illustrating 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 can receive energy from the battery system 100 and supply power to an electrical load, or can convert externally supplied energy to charge the battery system 100. A power management system (PMS) 300 can control the power conversion operation of 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 can be connected to both terminals P+ and P− of the battery system 100 and can transmit signals to control the power conversion operation of the power conversion system 200. The power management system 300 can also receive feedback information required to control 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 implement CAN communication, each system includes a CAN transceiver, which is connected to two CAN buses CAN_H and CAN_L. The battery system 100 includes a CAN transceiver 30, which can transmit and receive digital data with a battery management system (BMS) 20. The power conversion system 200 transmits and receives digital data with a CAN transceiver 210, and the power management system 300 transmits and receives digital data with a CAN transceiver 310. Each CAN transceiver 30, 210, and 310 can convert digital data received from a connected system into two voltages, which are differential signals, and transmit the converted data to each of the two CAN buses CAN_H and CAN_L. Alternatively, each CAN transceiver 30, 210, and 310 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 the corresponding system. Specifically, each CAN transceiver senses the voltage difference between the two CAN buses CAN_H and CAN_L, converts the sensed voltage difference into digital data, and uses an identifier in the converted digital data to identify the contents of a message and 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 order according to the assigned ID.

[0031] 1, the battery system 100, the power conversion system 200, and the CAN communication between the power conversion systems 200 via a 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 plurality of battery cells 10_1-10_n (n is a natural number equal to or greater than 2) connected in series. While FIG. 1 illustrates the battery pack 10 as including n battery cells 10_1-10_n connected in series, this is merely an example and the invention is not limited thereto. For example, a plurality of battery cells may be connected in series, each consisting of two or more parallel-connected battery cells. Alternatively, a plurality of battery cells may be connected in parallel, each consisting of a plurality of serially-connected battery cells. Both terminals P+ and P- of the battery pack 10 are connected to a power conversion system 200, and energy may be supplied from the battery pack 10 to the power conversion system 200 via both terminals 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 converts digital data received from the battery management system 20 into two voltages, which are differential signals, and transmits the converted data to the two CAN buses CAN_H and CAN_L. The CAN transceiver 30 converts the 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, it can transmit the message to the battery management system 20.

[0036] The power supply 50 can supply power to wake 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 constant level using the voltage of the battery pack 10. Alternatively, the power supply 50 can generate a power supply voltage at a constant level using the voltage from a separate battery that is separate from the battery pack 10.

[0037] The wake-up circuit 40 can connect the battery management system 20 to the power source 50 when a difference between two voltages received from the two CAN buses CAN_H and CAN_L indicates that the battery management system 20 should wake up.

[0038] The wake-up circuit 40 will now be described with reference to FIG.

[0039] FIG. 2 is a diagram illustrating 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 due to 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. A capacitor C1 is connected between the contact N1 and the contact N2, and a 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. A 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. The switch 46 is basically closed and can be opened when a current flows through the inductor 45.

[0042] Resistor R1 and capacitor C1 may form a low-pass filter, through which a voltage difference between the voltages of the CAN bus CAN_H and the CAN bus CAN_L (hereinafter, the CAN bus voltage difference) may be transmitted to photodiode PD. The low-pass filter including resistor R1 and capacitor C1 is connected in parallel to photodiode PD. The CAN bus voltage difference may be greater than or equal to a predetermined voltage to wake up the battery management system 20. For example, the power management system 300 may transmit a relatively high voltage to the CAN bus CAN_H and a relatively low voltage to the CAN bus CAN_L via the CAN transceiver 310. At this time, the CAN bus voltage difference may be greater than or equal to a threshold level that can turn on the photodiode PD. The photodiode PD is turned on by the CAN bus voltage difference, causing current to flow through the photodiode PD, causing it to emit light. When the photodiode PD emits light, phototransistor PT may be turned on. Phototransistor PT may be maintained in an on state during the period during which the photodiode PD emits light, and photodiode PD may emit light during the period during which the CAN bus voltage difference is greater than or equal to the 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 terminal, of the control transistor 41. The control transistor 41 is implemented as an npn BJT. Resistor R2 is connected between the emitter of the phototransistor PT and the base of the control transistor 41, and capacitor C2 is connected between the base of the control transistor 41 and ground. Resistor R2 and capacitor C2 can form a low-pass filter. The collector of the control transistor 41 is connected to the gate, which is the control terminal, of the power transistor 42, and the emitter of the control transistor 41 is connected to ground. Resistor R3 is connected between the base and emitter of the control transistor 41 to maintain a voltage difference between the base and 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 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, the 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 ground. The switch 47 is turned on when the relay opening signal RO is at an on level, and when the switch 47 is turned on, a current flows through the inductor 45, allowing the switch 46 to be opened.

[0046] The wake-up holding signal HS can be supplied to the base of the control transistor 41. During the period when 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. The relay may also 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] 3, relay 51 is connected between contact N1 and contact N_H. Relay 51 includes switch 52 and inductor 53. Switch 52 is connected between contact N1 and contact N_H, and one end of inductor 53 is supplied with voltage VDC. The other end of inductor 53 is connected to one end of switch 54, and the other end of switch 54 is connected to ground. Switch 54 is turned on at a turn-on level in accordance with relay open signal RO. When switch 47 is turned on, current flows through inductor 53, allowing switch 52 to open.

[0050] The wake-up operation will be described below 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. Voltages V2 and V3 may be the same level. When the CAN bus voltage difference between the first voltage V_H and the second voltage V_L exceeds a threshold level, the photodiode PD emits light and the phototransistor PT turns on. As described above, this turns on the power transistor 42, and the power supply 50 supplies voltage to the battery management system 20. The battery management system 20 wakes up using the voltage supplied from the power supply 50 and can perform necessary operations, such as monitoring the battery pack 10, after waking up. Furthermore, 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 from 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 falls below the threshold level, turning the photodiode PD off and not emitting light. This also turns off the phototransistor PT. Because the wake-up holding signal HS is applied at an ON level to the base of the control transistor 41, the power transistor 42 remains ON. The battery management system 20 can maintain the wake-up holding signal HS at an ON level from the time it wakes up until time T5, when it completes the required operations.

[0054] The battery management system 20 generates a relay open signal RO at an ON level at time T4. The ON level relay open signal RO 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, battery management systems maintained an inactive state in low-power mode and selectively woke up based on lower-level block messages in the protocol. However, the wake-up method according to the present invention can wake up based on the difference between voltages transmitted through two CAN buses without maintaining the low-power mode. Therefore, the battery management system according to the present invention can wait for a long period of time in 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 fall within 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 the first CAN bus line and the second CAN bus line, and a phototransistor turned on by light emitted from 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 connects the power source and the battery management system; The photodiode is and is turned on to 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. 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 of claim 1.

3. further comprising 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 the control end of the control transistor.

2. The wake-up circuit of claim 1.

5. further comprising 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 terminal and one end thereof, 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 connected to the power source, the other end of the power transistor is connected to the battery management system, and a gate of the power transistor is connected to one end of the control transistor.

2. The wake-up circuit of 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 supply for supplying voltage to the battery management system; a wake-up circuit connected to a first CAN bus line and a second CAN bus line, the wake-up circuit connecting the power source and 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; Battery system.

9. The wake-up circuit an optocoupler connected between the first CAN bus line and the second CAN bus line, the optocoupler including a photodiode that is turned on to emit 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; 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 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. The battery system of claim 9.

11. The wake-up circuit further comprising 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 the control end of the control transistor. The battery system of claim 9.

13. The wake-up circuit further comprising a low-pass filter connected between the other end of the phototransistor and the control end of the control transistor. The battery system of claim 12.

14. The wake-up circuit The control transistor further includes a resistor connected between a control terminal and one end thereof, 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 connected to the power source, the other end of the power transistor is connected to the battery management system, and a gate of the power transistor is connected to one end of the control transistor. The battery system of claim 9.

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