KR102678943B1 - Battery Management System and Battery Management Method - Google Patents

Abstract

The battery management system of the present invention is a system for managing a battery pack including a plurality of cells, comprising: a cell monitoring IC connected to both ends of each of the plurality of cells to measure a cell voltage of each of the plurality of cells; and a time control unit that counts the wake-up cycle when the relay is turned off. And when the wake-up period elapses, the sleep mode is switched to the wake-up mode, receives the measured cell voltage of each of the plurality of cells, determines whether cell balancing is necessary based on the cell voltage of each of the plurality of cells, and determines whether cell balancing is necessary. When balancing is required, it includes a main control circuit that transfers a cell balancing control signal to the cell monitoring IC and then switches to a sleep mode.

Description

Battery Management System and Battery Management Method

The present invention relates to a battery management system (BMS) and a battery management method that can be used in devices that use electrical energy.

Cars that primarily use fossil fuels such as gasoline have a serious impact on air pollution and other pollutants, so much effort has recently been made in the development of electric vehicles (EVs) or hybrid vehicles (HEVs). .

Electric vehicles (EVs) or hybrid vehicles (HEVs) that use electrical energy use a battery composed of a number of secondary batteries (cells) capable of charging/discharging as one pack as their main power source. Therefore, since the performance of the battery directly affects the performance of the vehicle, the role of the battery management system (BMS), which monitors the battery and manages it in an optimal state, is important.

Meanwhile, voltage differences between battery cells inevitably occur due to structural differences between a plurality of battery cells. Since this deviation acts as a cause of battery deterioration, battery cell balancing operation to maintain equal voltage between battery cells is a very important element of a battery management system (BMS).

If the car engine is turned on and put into driving mode during battery cell balancing, the battery cell balancing operation is stopped while the voltage between battery cells is not equalized. Additionally, if the entire battery management system (BMS) is turned on while cell balancing of the battery is performed, there is a problem of unnecessary battery consumption.

The present invention seeks to provide a battery management system and method for operating an MCU in a sleep mode while battery cell balancing is performed by resetting the maximum time required for battery cell balancing to a wake-up time.

The present invention seeks to provide a battery management system and method that performs battery cell balancing when the engine is turned off and the vehicle is changed to a parked state.

A battery management system according to an aspect of the present invention is a system for managing a battery pack including a plurality of cells, and a cell monitoring system that is connected to both ends of each of the plurality of cells to measure the cell voltage of each of the plurality of cells. IC; and a time control unit that counts the wake-up cycle when the relay is turned off. And when the wake-up period elapses, the sleep mode is switched to the wake-up mode, receives the measured cell voltage of each of the plurality of cells, determines whether cell balancing is necessary based on the cell voltage of each of the plurality of cells, and determines whether cell balancing is necessary. It includes a main control circuit that transfers a cell balancing control signal to the cell monitoring IC when balancing is necessary and then switches to a sleep mode.

The main control circuit may calculate a plurality of cell balancing times for a plurality of cells selected as cell balancing targets and generate a wake-up control signal based on the maximum cell balancing time among the plurality of cell balancing times.

The time control unit may receive the wake-up control signal from the main control circuit and reset the wake-up period based on the maximum cell balancing time.

The main control circuit may switch from sleep mode to wake-up mode when the reset wake-up period elapses.

The main control circuit monitors whether a predetermined minimum time has elapsed when the relay is turned off, and transmits a parking signal to the time control unit when the minimum time has elapsed. The time control unit wakes when receiving the parking signal. Up cycles can be counted.

The main control circuit may disable the wake-up operation of the time controller when there is no cell balancing target.

A battery management method according to another feature of the present invention is a method of managing a battery pack including a plurality of cells, wherein when the relay is turned off and the wake-up period has elapsed, a wake-up signal is received from the time control unit and the battery pack is maintained in sleep mode. Switching to wake-up mode; Requesting and receiving the cell voltage of each of a plurality of cells from a cell monitoring IC, determining whether cell balancing is necessary based on the cell voltage of each of the plurality of cells, and generating a cell balancing control signal if cell balancing is necessary; and transferring the cell balancing control signal to the cell monitoring IC and then switching to a sleep mode.

The step of generating the cell balancing control signal includes calculating a plurality of cell balancing times for a plurality of cells selected as cell balancing targets and generating a wakeup control signal based on the maximum cell balancing time among the plurality of cell balancing times. can do.

In the step of switching to the sleep mode, the wake-up period may be reset based on the maximum cell balancing time by transmitting the wake-up control signal to the time controller.

The step of switching to the sleep mode may include switching from the sleep mode to the wake-up mode by receiving a wake-up signal from the time control unit when the reset wake-up period has elapsed.

In the step of switching to the wake-up mode, when the relay is turned off and the wake-up period arrives after a minimum time has elapsed, a wake-up signal can be received from the time control unit to switch from the sleep mode to the wake-up mode.

The step of switching to the sleep mode may disable the wake-up operation of the time controller when there is no cell balancing target.

The present invention has the effect of preventing unnecessary wake-up by resetting the maximum time required for battery cell balancing to the wake-up time and saving energy by operating the MCU in sleep mode while battery cell balancing is performed.

The present invention has the effect of increasing the lifespan of the battery by preventing battery cell balancing from stopping before completion and maintaining the voltage between battery cells uniformly.

1 is a diagram showing a battery system according to an embodiment.
FIG. 2 is a block diagram illustrating the function of the main control circuit of FIG. 1.
FIG. 3 is a diagram illustrating the wake-up operation of the main control circuit of FIG. 1.
FIG. 4 is a diagram illustrating an operation in which the main control circuit wakes up by distinguishing between a temporarily stopped state and a long-term parked state of the vehicle, according to an embodiment.
Figure 5 is a flowchart explaining a battery management method according to an embodiment.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings, but identical or similar components will be assigned the same or similar reference numerals and duplicate descriptions thereof will be omitted. The suffixes “module” and/or “part” for components used in the following description are given or used interchangeably only for the ease of preparing the specification, and do not have distinct meanings or roles in themselves. Additionally, in describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions will be omitted. In addition, the attached drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings, and all changes included in the spirit and technical scope of the present invention are not limited. , should be understood to include equivalents or substitutes.

Terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that it does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

1 is a diagram showing a battery system according to an embodiment.

As shown in FIG. 1, the battery system 1 includes a battery pack 2, a relay 3, and a battery management system (BMS) 4.

The battery pack 2 can supply necessary power by connecting a plurality of battery cells in series/parallel. In Figure 1, the battery pack 2 includes a plurality of battery cells (Cell1-Celln) connected in series, and is connected between the two output terminals (OUT1 and OUT2) of the battery system 1. ) A relay (3) is connected between the anode of ) and the output terminal (OUT1). The configurations shown in FIG. 1 and the connection relationships between the configurations are examples, and the invention is not limited thereto.

The relay (3) controls the electrical connection between the battery system (1) and external devices. When the relay 3 is turned on, the battery system 1 and the external device are electrically connected and charging or discharging is performed, and when the relay 3 is turned off, the battery system 1 and the external device are connected. are electrically separated. The external device can be a load or charger.

The BMS 4 includes a cell balancing circuit 10, a cell monitoring IC 20, a time control unit 30, and a main control circuit 40.

The cell balancing circuit 10 includes a plurality of switches (SW1-SWn) and a plurality of resistors (R1-Rn). Each of the plurality of switches (SW1-SWn) performs a switching operation according to a corresponding switching signal among the plurality of switching signals (SC[1]-SC[n]) supplied from the cell monitoring IC 20. For each of the plurality of cells (Cell1-Celln), the corresponding switch (SWi) and resistor (Ri) are connected in series between the anode and cathode of the corresponding cell (Celli). When the switch SWi is turned on, a discharge path is formed between the corresponding cell (Celli), the switch (SWi), and the resistor (Ri), and the corresponding cell (Celli) discharges. At this time, i is one of the natural numbers from 1 to n.

The cell monitoring IC 20 may include a Battery Monitoring IC (BMIC). The cell monitoring IC 20 is electrically connected to the anode and cathode of each of the plurality of cells (Cell1-Celln) and measures the cell voltage. The current (hereinafter referred to as battery current) value measured by a current sensor (not shown) may be transmitted to the cell monitoring IC 20. The cell monitoring IC 20 transmits information about the measured cell voltage and battery current to the main control circuit 40.

The cell monitoring IC 20 may discharge cells subject to cell balancing among the plurality of cells (Cell1-Celln) through the cell balancing circuit 10 according to the cell balancing control signal transmitted from the main control circuit 40. For example, the cell monitoring IC 20 may generate a plurality of switching signals (SC[1] to SC[n]) according to the cell balancing control signal of the main control circuit 40. Each of the switching signals (SC[1] to SC[n]) can control the switching operation of the corresponding switch (SWi). When the on-level switching signal (SC[i]) is supplied to the corresponding switch (SWi), the switch (SWi) is turned on and the corresponding cell (Celli) is discharged.

The time control unit 30 may include a Real Time Clock (RTC). The RTC can generate a clock signal of a certain frequency and monitor the passage of time by counting the clock signal.

The time control unit 30 can count the wake-up period when it receives a parking signal including parking status information of the vehicle from the main control circuit 40. When the wake-up period arrives, the time control unit 30 transmits a wake-up signal to the main control circuit 40, and the main control circuit 40 that receives the wake-up signal wakes up. The wake-up period may be a preset period and may be reset by the wake-up control signal of the main control circuit 40. For example, the turn-off of the relay 3 may be in a stopped or parked state where the vehicle ignition is OFF.

The time control unit 30 may receive a wake-up control signal from the main control circuit 40 and reset the wake-up period. The time control unit 30 may count the reset wake-up period and transmit a wake-up signal to the main control circuit 40.

The main control circuit 40 may include a Micro Control Unit (MCU). When the relay 3 is turned off, the operation mode of the main control circuit 40 becomes sleep mode. The operation modes of the main control circuit 40 include drive mode, sleep mode, and wake-up mode. The driving mode is a mode in which the main control circuit 40 controls the battery pack 2 as the relay 3 is turned on, and the sleep mode is a mode in which the main control circuit 40 is idle as the relay 3 is turned off. ) state, and in the wake-up mode, the main control circuit 40 is temporarily activated after the relay 3 is turned off, monitors the battery pack 2, determines whether cell balancing is necessary, and performs cell balancing. This mode generates a control signal for cell balancing when necessary.

For example, when the relay 3 is turned off and a wake-up cycle arrives or a reset wake-up cycle arrives, the main control circuit 40 receives a wake-up control signal from the time controller 30 and enters the sleep mode. switches to wake-up mode.

Hereinafter, with reference to FIGS. 2 to 4, the cell balancing control operation in the wake-up mode of the main control circuit 40 will be described.

FIG. 2 is a block diagram illustrating the function of the main control circuit of FIG. 1.

Referring to FIG. 2, the main control circuit 40 includes a wake-up module 41, an operation module 43, and a control module 45.

The wake-up module 41 switches the operation mode to sleep mode when the relay 3 is turned off. For example, when the relay 3 is turned off, the wake-up module 41 monitors whether a predetermined minimum time has elapsed, distinguishes between a temporarily stopped state and a long-term parked state, and stops the vehicle when the predetermined minimum time has elapsed. If it is determined to be in this parking state, a parking signal including information on the parking state of the vehicle can be transmitted to the time control unit 30. The wake-up module 41 may transfer the parking signal to the time control unit 30 and then change the operation mode to the sleep mode. The minimum time can be set by the user as the minimum time to distinguish between temporary stopping and long-term parking of the vehicle.

When the wake-up module 41 receives a wake-up signal from the time control unit 30, it wakes up and switches the operation mode from sleep mode to wake-up mode. For example, the wake-up module 41 may determine the source of the received wake-up signal and change the operation mode to the wake-up mode if it is determined that it has been transmitted from the time control unit 30.

The operation module 43 generates a cell balancing control signal. First, the operation module 43 requests the cell monitoring IC 20 to measure the cell voltages of a plurality of cells (Cell1-Celln). When receiving a plurality of cell voltages from the cell monitoring IC 20, the operation module 43 determines whether cell balancing is necessary based on the cell voltage of each of the plurality of cells (Cell1-Celln), and if cell balancing is necessary, the cell Generates control signals for balancing.

For example, when a cell voltage that is outside the reference voltage range is detected among a plurality of cell voltages, the calculation module 43 selects the corresponding cell as a cell balancing target and generates a cell balancing control signal according to the selection result. The reference voltage range may be set based on a plurality of cell voltages. Specifically, considering the voltage distribution of a plurality of cells, the reference voltage range may be set to an appropriate voltage range capable of detecting cells that are overvoltage or undervoltage compared to other cells. If the cell balancing method is a passive method that only performs discharge, the operation module 43 may decide to perform cell balancing on cells with a cell voltage higher than the reference voltage, and at this time, the reference voltage range is the plurality of cell voltage distributions. Considering, it can be set to a voltage range that can detect cells that are overvoltage compared to other cells.

The operation module 43 generates a wake-up control signal. The calculation module 43 calculates a plurality of cell balancing times for a plurality of cells (Cell1-Celln) selected as cell balancing targets. The calculation module 43 extracts the maximum cell balancing time among the plurality of cell balancing times and generates a wake-up control signal based on the maximum cell balancing time.

The control module 45 transmits a cell balancing control signal to the cell monitoring IC 20 to activate cell balancing. When the control module 45 transmits the wake-up control signal to the time control unit 30, the time control unit 30 resets the wake-up period based on the received wake-up control signal. Afterwards, the time control unit 30 counts the reset wake-up period and transmits a wake-up signal to the wake-up module 41.

The control module 45 switches the operation mode of the main control circuit 40 from the wake-up mode to the sleep mode during the period during which cell balancing is performed, for example, the maximum cell balancing time. If there is no cell balancing target as a result of the operation of the operation module 43, the control module 45 may disable the wake-up operation of the time controller 30.

FIG. 3 is a diagram illustrating the operation of waking up the main control circuit of FIG. 1, and FIG. 4 illustrates the operation of waking up the main control circuit by distinguishing between a temporary stopped state and a long-term parking state of the vehicle according to an embodiment. This is a drawing.

Referring to FIG. 3, at time T _a , the main control circuit 40 is synchronized with the turn-off of the relay 3 and monitors whether a predetermined minimum time has elapsed without switching to the sleep mode to determine the vehicle's temporary stop status and long-term stop status. Parking status can be distinguished.

At time T _b , if the main control circuit 40 determines that the vehicle is in a parked state after a predetermined minimum time has elapsed, it may transmit a parking signal including information on the parking state of the vehicle to the time control unit 30. The main control circuit 40 may transfer the parking signal to the time control unit 30 and then change the operation mode to sleep mode. The time control unit 30 can count the wake-up period when receiving a parking signal from the main control circuit 40.

At time T _c , the time control unit 30 transmits a wake-up signal to the main control circuit 40 when the wake-up period arrives, and the main control circuit 40 that receives the wake-up signal wakes up and enters the wake-up mode. is converted to

The main control circuit 40 receives the plurality of cell voltages by requesting the cell monitoring IC 20 to measure the cell voltages of the plurality of cells (Cell1-Celln). The main control circuit 40 determines whether cell balancing is necessary based on the cell voltage of each of the plurality of cells (Cell1-Celln), and generates a control signal for cell balancing if cell balancing is necessary. The main control circuit 40 calculates a plurality of cell balancing times for a plurality of cells (Cell1-Celln) selected as cell balancing targets, extracts the maximum cell balancing time among the plurality of cell balancing times, and calculates the maximum cell balancing time. Generates a wake-up control signal based on time.

At time T _d , the main control circuit 40 transmits a cell balancing control signal to the cell monitoring IC 20 to activate cell balancing and transmits a wake-up control signal to the time controller 30. The time control unit 30 resets the wake-up period based on the received wake-up control signal. For example, if cell balancing starts at T _d , the maximum cell balancing time is from time T _d to T _e , and the operation mode of the main control circuit 40 during that period is sleep mode.

At time T _e , the time controller 30 counts the reset wake-up period and transmits a wake-up signal to the main control circuit 40. When the main control circuit 40 receives a wake-up signal from the time control unit 30, it switches the operation mode to the wake-up mode.

Referring to FIG. 4, the relay 3 is turned off at time T ₁ but is turned on again at time T ₂ before the minimum time has elapsed, so the main control circuit 40 determines that the vehicle is in a stopped state and sends a parking signal. is not transmitted to the time control unit 30. For example, cell balancing cannot be performed if the vehicle stops temporarily and then starts again.

At time T ₃ , the relay 3 is turned off again. For example, at time T ₄ when the minimum time has elapsed, the main control circuit 40 determines that the vehicle is in a parked state and sends a parking signal to the time control unit 30. ) can be passed on. The time control unit 30 can count the wake-up period when receiving a parking signal from the main control circuit 40.

At time T ₅ , the time control unit 30 transmits a wake-up signal to the main control circuit 40, and the main control circuit 40 wakes up. For example, a vehicle may enter a long-term parking state and perform cell balancing.

Figure 5 is a flowchart explaining a battery management method according to an embodiment.

First, the main control circuit 40 wakes up when it receives a wake-up signal from the time control unit 30 and switches the operation mode from sleep mode to wake-up mode. For example, the main control circuit 40 may determine the source of the received wake-up signal and, if it is determined that it has been transmitted from the time control unit 30, switch the operation mode to the wake-up mode (S10).

The turn-off of the relay 3 may be in a stopped or parked state where the vehicle ignition is changed to the ON state. The main control circuit 40 determines that the vehicle is temporarily stopped when the relay 3 is turned off and the relay 3 is turned on again before the minimum time has elapsed, and does not transmit a parking signal to the time control unit 30. It may not be possible. If the turn-off state of the relay 3 does not change even after the minimum time has elapsed, the main control circuit 40 determines that the vehicle has been parked for a long period of time and transmits a parking signal to the time control unit 30. The main control circuit 40 may transfer the parking signal to the time control unit 30 and then change the operation mode to sleep mode.

The time control unit 30 can count the wake-up period when it receives a parking signal including parking status information of the vehicle from the main control circuit 40. The time control unit 30 may transmit a wake-up signal to the main control circuit 40 when the wake-up period arrives. The wake-up period may be a preset period and may be reset by the wake-up control signal of the main control circuit 40.

Next, the main control circuit 40 generates a control signal to perform cell balancing. The main control circuit 40 generates a cell balancing control signal for a plurality of cells (Cell1-Celln) and a wakeup control signal for resetting the wakeup period (S30).

The main control circuit 40 generates a cell balancing control signal. First, the main control circuit 40 requests the cell monitoring IC 20 to measure the cell voltages of a plurality of cells (Cell1-Celln). When receiving a plurality of cell voltages from the cell monitoring IC 20, the main control circuit 40 determines whether cell balancing is necessary based on the cell voltages of each of the plurality of cells (Cell1-Celln), and when cell balancing is necessary, the main control circuit 40 determines whether cell balancing is necessary. Generates control signals for cell balancing.

For example, when the main control circuit 40 detects a cell voltage that is outside the reference voltage range among a plurality of cell voltages, it selects the corresponding cell as a cell balancing target and generates a cell balancing control signal according to the selection result. The reference voltage range may be set based on a plurality of cell voltages. Specifically, considering the voltage distribution of a plurality of cells, the reference voltage range may be set to an appropriate voltage range capable of detecting cells that are overvoltage or undervoltage compared to other cells. If the cell balancing method is a passive method that only performs discharge, the operation module 43 may decide to perform cell balancing on cells with a cell voltage higher than the reference voltage, and at this time, the reference voltage range is the plurality of cell voltage distributions. Considering, it can be set to a voltage range that can detect cells that are overvoltage compared to other cells.

The main control circuit 40 generates a wake-up control signal. The main control circuit 40 calculates a plurality of cell balancing times for a plurality of cells (Cell1-Celln) selected as cell balancing targets. The main control circuit 40 extracts the maximum cell balancing time among the plurality of cell balancing times and generates a wake-up control signal based on the maximum cell balancing time.

Next, the main control circuit 40 controls peripheral devices for cell balancing and switches to sleep mode. The main control circuit 40 may disable the wake-up operation of the time control unit 30 when there is no cell balancing target (S50).

The main control circuit 40 transmits a cell balancing control signal to the cell monitoring IC 20 to activate cell balancing. The main control circuit 40 transmits a wake-up control signal to the time control unit 30 and resets the wake-up period based on the wake-up control signal received by the time control unit 30. Afterwards, the time control unit 30 counts the reset wake-up period and transmits a wake-up signal to the main control circuit 40.

The main control circuit 40 switches the operation mode to a sleep mode during the period during which cell balancing is performed, for example, the maximum cell balancing time.

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 in the field to which the present invention pertains are also within the rights of the present invention. belongs to the range

1: Battery system
2: Battery pack
3: relay
4:BMS
10: Cell balancing circuit
20: Cell monitoring IC
30: time control unit
40: main control circuit

Claims (12)

In a system for managing a battery pack including a plurality of cells,
a cell monitoring IC connected to both ends of each of the plurality of cells to measure a cell voltage of each of the plurality of cells; and
a time control unit that counts the wake-up cycle when the relay is turned off; and
When the wake-up period elapses, the sleep mode is switched to the wake-up mode, the measured cell voltage of each of the plurality of cells is received, and based on the cell voltage of each of the plurality of cells, it is determined whether cell balancing is necessary, and cell balancing is performed. When necessary, it includes a main control circuit that transfers a cell balancing control signal to the cell monitoring IC and then switches to a sleep mode,
The main control circuit is,
Calculate a plurality of cell balancing times for a plurality of cells selected for cell balancing and generate a wake-up control signal based on the maximum cell balancing time among the plurality of cell balancing times,
The time control unit,
Receiving the wakeup control signal from the main control circuit and resetting the wakeup period based on the maximum cell balancing time,
The main control circuit is,
A battery management system that switches from sleep mode to wake-up mode when the reset wake-up cycle elapses. delete delete delete According to paragraph 1,
The main control circuit is,
When the relay is turned off, it monitors whether a predetermined minimum time has elapsed and transmits a parking signal to the time control unit when the minimum time has elapsed,
The time control unit,
A battery management system that counts the wake-up cycle when the parking signal is received. According to paragraph 1,
The main control circuit is,
A battery management system that disables the wake-up operation of the time control unit when there is no cell balancing target. In a method of managing a battery pack including a plurality of cells,
When the relay is turned off and the wake-up period elapses, receiving a wake-up signal from the time control unit and switching from the sleep mode to the wake-up mode;
Requesting and receiving the cell voltage of each of a plurality of cells from a cell monitoring IC, determining whether cell balancing is necessary based on the cell voltage of each of the plurality of cells, and generating a cell balancing control signal if cell balancing is necessary; and
Contains transferring the cell balancing control signal to the cell monitoring IC and then switching to a sleep mode,
The step of generating the cell balancing control signal is:
Calculate a plurality of cell balancing times for a plurality of cells selected for cell balancing and generate a wake-up control signal based on the maximum cell balancing time among the plurality of cell balancing times,
The step of switching to the sleep mode is,
The wake-up period is reset based on the maximum cell balancing time by transmitting the wake-up control signal to the time controller,
The step of switching to the sleep mode is,
A battery management method in which, when the reset wake-up period elapses, a wake-up signal is received from the time controller and the sleep mode is converted to a wake-up mode. delete delete delete In clause 7,
The step of switching to the wake-up mode is,
A battery management method in which, when the relay is turned off and the wake-up period arrives after a minimum time has elapsed, a wake-up signal is received from the time control unit and the sleep mode is converted to a wake-up mode. In clause 7,
The step of switching to the sleep mode is,
A battery management method that disables the wake-up operation of the time control unit when there is no cell balancing target.