Patent Description:
In a vehicle in a normal state, a battery management system (BMS) of a battery installed in the vehicle receives a relay control instruction from an electronic control unit (ECU) of the vehicle through a CAN communication, analyzes the received relay control instruction, and controls a relay.

When the CAN communication between the higher-level ECU and the BMS has a defect, the higher-level ECU loses a control right to the relay, and in correspondence to this, the BMS forcibly opens the relay regardless of the higher-level ECU, and has the battery system enter a safe state.

This may prevent the battery system from being abnormally controlled, but the vehicle fails to receive power from the battery system. The vehicle may not drive normally or may drive but in a limited way because the power supply from the battery system is blocked. A user of the vehicle may then feel uneasy or fall into risky situations.

The present invention has been made in an effort to provide a BMS and an ECU for providing communication between the ECU and the BMS when there is a CAN communication disruption between the ECU and the BMS, and a communication method therebetween.

The BMS and the ECU for providing communication between the ECU and the BMS even when there is a CAN communication problem between the ECU and the BMS, and a communication method therebetween, are provided.

A communication method according to an exemplary embodiment of the present invention is a single line communication method according to a half-duplex scheme using a pulse signal (hereinafter, a modulated pulse signal) obtained by modulating a frequency and a duty cycle between the BMS and the ECU.

First, the ECU transmits the pulse signal with the modulated frequency and the duty cycle to the BMS so as to instruct a switching operation of a control target relay from among a plurality of relays. The BMS controls the switching operation of the corresponding relay according to the modulating pulse signal received from the ECU. The BMS controls a first voltage change period to a communication line and feeds back to the ECU so as to instruct a switching result of the corresponding relay according to a modulating pulse signal. A state of the relay is one of open and closed, and changing the state of the relay is referred to as a switching operation.

In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

<FIG> shows a block diagram of a configuration of an ECU and a BMS to which a communication method according to an exemplary embodiment is applied.

As shown in <FIG>, the BMS <NUM> includes a micro control unit (MCU) <NUM>, and the ECU <NUM> includes a MCU <NUM>.

The MCU <NUM> includes an input capture unit (ICU) <NUM>, a digital input output (DIO) module <NUM>, and a relay control module <NUM>, and the MCU <NUM> includes a modulating signal generator <NUM> and an ICU <NUM>.

The BMS <NUM> is connected to the ECU <NUM> through a single line <NUM> and a CAN communication line <NUM>. The BMS <NUM> receives a relay control instruction from the ECU <NUM> according to a CAN communication using the CAN communication line <NUM>, and controls the relay according to the relay control instruction. However, in the case of a CAN communication defect because of a problem in the CAN communication line <NUM>, etc., it may receive a relay control signal (hereinafter, a modulating pulse signal) from the ECU <NUM> according to a half-duplex communication using the single line <NUM>.

The modulating pulse signal (MPS) is transmitted to the BMS <NUM> from the ECU <NUM> through the single line <NUM>, and the BMS <NUM> controls the relay according to the modulating pulse signal (MPS) and applies a first voltage level to the single line <NUM> as feedback by a period that corresponds to feedback information. In an exemplary embodiment, the first voltage may be a ground level, but the present invention is not limited thereto, and the ECU <NUM> may be another level for recognizing a change of voltage.

A first end of the single line <NUM> is connected to an external pin P1 of the ICU <NUM>, and a second end of the single line <NUM> is connected to an external pin P2 of the modulating signal generator <NUM> and an external pin P3 of the ICU <NUM>, so a half-duplex communication path between the BMS <NUM> and the ECU <NUM> is formed.

The ICU <NUM> measures a frequency and a duty cycle of the modulating pulse signal (MPS) received through the single line <NUM>. The ICU <NUM> generates information (hereinafter, relay control information) on the frequency and the duty cycle of the measured modulating pulse signal (MPS), and transmits the same to the relay control module <NUM>.

The relay control module <NUM> controls the switching operation of the corresponding relay based on the received relay control information. The relay control module <NUM> may open or close the relay that corresponds to the relay control information from among a plurality of relays according to the relay control information. After completing a relay control operation according to the relay control information, the relay control module <NUM> transmits information (hereinafter, relay control result information) for instructing a relay control result to the DIO module <NUM>. The relay control result information instructs the relay operated according to the relay control information from among a plurality of relays and a voltage change period determined according to a state of the corresponding relay. The relay control module <NUM> may also request transmission of the modulating pulse signal (MPS) to the BMS <NUM> from the ECU <NUM>. For example, the relay control module <NUM> transmits relay control request information for requesting a modulating pulse signal (MPS) to the DIO module <NUM>. The relay control request information may instruct a voltage change period determined according to the relay requiring relay control from among a plurality of relays and a state required of the corresponding relay. An example of the voltage change may be a pull-down.

After receiving relay control result information or relay control request information, the DIO module <NUM> may control the switching operation of the switch <NUM> according to the received information and generates a switching signal (SC) for changing a voltage at the single line <NUM> for a voltage change period according to relay control result information or relay control request information in the communication line <NUM>. The DIO module <NUM> may transmit a switching signal (SC) to the switch <NUM> through an external pin P4. The switch <NUM> may perform a switching operation according to a level of the switching signal (SC). The switch <NUM> may be realized with a transistor operable in an electronic way according to the switching signal (SC) or a relay operable in a mechanical way.

The modulating signal generator <NUM> generates a modulating pulse signal (MPS) having a frequency and a duty cycle according to a control target relay and an instruction (hereinafter, a relay control instruction) on a state of the control target relay. The modulating signal generator <NUM> may apply a modulating pulse signal (MPS) to the communication line <NUM> through the external pin P2. A relay control instruction may be generated by the ECU <NUM>.

The ICU <NUM> is connected to the single line <NUM> through the external pin P3, and it measures the frequency and the duty cycle of the single line <NUM> so as to detect a voltage change of the single line <NUM>. For example, when the switch <NUM> is turned on and the single line <NUM> is grounded, the single line <NUM> is pulled down. For an On period of the switch <NUM>, the single line <NUM> is in a pull-down state. The ICU <NUM> may measure the frequency and the duty cycle of the single line <NUM> to detect how long the single line <NUM> is in the pull-down state. The ICU <NUM> may generate information on a detection result, and the ECU <NUM> may recognize feedback information on the relay control result based on generated information, and may generate a relay control instruction in response to a relay control request.

<FIG> shows a relay control module and a relay according to an exemplary embodiment.

In <FIG>, a battery device <NUM> includes a BMS <NUM> and a battery cell assembly <NUM>, and a plurality of relays (400_1 to 400_n) for controlling power supply are electrically connected between the battery cell assembly <NUM> and a plurality of electrical loads (500_1 to 500_n).

A plurality of battery cells of the battery cell assembly <NUM> are connected in series/parallel to each other to supply power. The battery cells may be electrically connected to the BMS <NUM> through a plurality of wires.

As shown in <FIG>, the relay control module <NUM> includes a plurality of relay drivers (120_1 to 120_n), and the plurality of relay drivers (120_1 to 120_n) may respectively control the switching operation of the corresponding relay from among a plurality of relays (400_1 to 400_n). The BMS <NUM> may collect and analyze various information on the battery device including information on a plurality of battery cells, and may control charging and discharging of the battery device, balancing of battery cells, and a protection operation.

The relay control module <NUM> controls the operation of the corresponding relay driver from among a plurality of relay drivers (120_1 to 120_n) based on relay control information received from the ICU <NUM>.

For example, when the relay control information instructs that the modulating pulse signal (MPS) has a frequency F1 [Hz] and D1 [%], the relay control module <NUM> recognizes it as a control instruction for opening the first relay 400_1, and controls the relay driver 120_1 to generate an Off-level relay switching signal RLC1 for opening the relay 400_1. The relay driver 120_1 generates an Off-level relay switching signal RLC1, and the relay 400_1 is turned to Off and enters an open state according to the Off-level relay switching signal RLC1.

The relay control module <NUM> controls the corresponding relay according to relay control information, and transmits relay control result information to the DIO module <NUM> so as to transmit a control result to the ECU <NUM> as a feedback. For example, when the relay 400_1 enters an open state, the relay control module <NUM> transmits relay control result information for instructing a period of T1[s] to the DIO module <NUM>, and the DIO module <NUM> turns on the switch <NUM> for the period of T1[s]. The single line <NUM> is pulled down to a ground voltage for the period of T1[s].

In another way, when the relay control information instructs that the modulating pulse signal (MPS) has the frequency of F1[Hz] and D2[%], the relay control module <NUM> recognizes it as a control instruction for closing the first relay 400_1, and controls the relay driver 120_1 to generate an On-level relay switching signal RLC1 for closing the relay 400_1. The relay driver 120_1 generates an On-level relay switching signal RLC1, and the relay 400_1 is turned to On according to the On-level relay switching signal RLC1 and enters a closed state.

When the relay 400_1 enters the closed state, the relay control module <NUM> transmits relay control result information for instructing the period of T2[s] to the DIO module <NUM>, and the DIO module <NUM> turns on the switch <NUM> for the period of T2[s]. The single line <NUM> is pulled down to the ground voltage for the period of T2[s].

<FIG> shows a waveform diagram of a voltage change in a single line according to an exemplary embodiment.

As shown in <FIG>, the modulating pulse signal (MPS) with the frequency of F1[Hz] and D1[%] is applied to the single line <NUM> in a MPS section PT1. A high level of the modulating pulse signal (MPS) is a power supply voltage level VCC for driving the MCU <NUM>, and a low level is illustrated to be the ground, but the present invention is not limited, and the high level and the low level may be appropriately set depending on designs.

For a predetermined period PT2, the input capture unit (ICU) <NUM> measures the frequency and the duty cycle of the modulating pulse signal (MPS) received in the MPS section PT1, generates relay control information, and transmits the same to the relay control module <NUM>, and the relay control module <NUM> controls the relay 400_1 to be in the open state, and transmits relay control result information for instructing T1[s] to the DIO module <NUM>.

For a BMS response period PT3, the DIO module <NUM> turns on the switch <NUM> for T1[s] to pull down the voltage at the single line <NUM> to the ground (GND).

For the period PT2 and the BMS response period PT3 after the MPS section PT1 ends, the ICU <NUM> measures the frequency and the duty cycle of the single line <NUM> to detect a pull-down period of the single line <NUM> and recognize a relay control result.

Table <NUM> shows relay control information that corresponds to the frequency and the duty cycle of the modulating pulse signal received from the ECU <NUM>, relay control information on states of the relays, and responses of the corresponding BMS <NUM>.

In Table <NUM>, a reciprocal number of a minimum frequency from among frequencies F1 to Fn must be smaller than the minimum value of the pull-down periods T1 to Tk. This is to distinguish information transmitted/received through the single line <NUM>.

As can be known from Table <NUM>, specific frequencies are allocated to a plurality of relays, the duty cycle when the state of each relay is open is D1 %, the duty cycle when it is closed is D2 %, and the period (e.g., T1[s]) for instructing a time when a relay control result that is a BMS response is open may be different from the period (e.g., T2[s]) for instructing a time when it is closed.

Table <NUM> shows an exemplary embodiment, the present invention is not limited thereto, and it is modifiable according to designs in a range of the frequency bandwidth and the duty cycle recognizable by the BMS <NUM> and the ECU <NUM>.

The relay control module <NUM> may generate relay control request information, and the DIO module <NUM> may control the switch <NUM> according to relay control request information and may pull down the single line <NUM>.

For example, the relay control module <NUM> transmits relay control request information for instructing Tm[s] to the DIO module <NUM>, and the DIO module <NUM> turns on the switch <NUM> for Tm[s] according to relay control request information. The ICU <NUM> measures the frequency and the duty cycle of the single line <NUM> to detect the pull-down period Tm[s] of the single line <NUM>, and outputs a detection result to the ECU <NUM>. The ECU <NUM> may generate a relay control instruction for opening the relay 400_1 according to a detection result, and may transmit the same to the modulating signal generator <NUM>.

When the relay control module <NUM> requests relay control, it may transmit trigger information for notifying it to the DIO module <NUM> before relay control request information. The DIO module <NUM> may control the switching operation of the switch <NUM> according to trigger information to control the voltage waveform of the single line <NUM> to have a specific frequency and duty cycle. The ICU <NUM> may recognize that relay control request information will be transmitted when measuring the specific frequency and the duty cycle through the single line <NUM>. The frequency and the duty cycle of the single line <NUM> measured after recognition correspond to relay control request information, and the ICU <NUM> detects Tm[s] that corresponds to relay control request information, and outputs a detection result that corresponds to relay control request information to the ECU <NUM>. The ECU <NUM> may generate a relay control instruction according to a detection result and may transmit the same to the ICU <NUM>.

Claim 1:
A Battery Manager System (<NUM>), BMS, connected to an Electronic Control Unit (<NUM>), ECU, by Controller Area Network, CAN, communication (<NUM>) and half-duplex communication through a single line (<NUM>), the BMS comprising:
an Input Capture Unit (<NUM>), ICU, for, when the CAN communication has a defect, measuring a frequency and a duty cycle of a modulating pulse signal through the single line, and generating relay control information;
a relay control module (<NUM>) for generating a relay control signal for controlling a switching operation of a corresponding relay from among a plurality of relays (400_1 to 400_n) based on the relay control information, and generating relay control result information for instructing a control result of the corresponding relay; and
a Digital Input Output (<NUM>), DIO, module for changing a voltage at the single line so as to transmit relay control result information to the ECU for a period based on the relay control result information,
wherein the plurality of relays are electrically connected between a battery device including the BMS and an electrical load (500_1 to 500_n).