Patent Description:
A secondary battery, which has high application easiness according to a product group and an electric characteristic, such as a high energy density, has been universally applied to an electric vehicle (EV) and a hybrid vehicle (HV) driven by an electric driving source, or an energy storage system (ESS), an uninterruptible power supply (UPS) system, or the like using a medium and large battery used for a house or an industry, as well as a portable device.

The secondary battery attracts attention as a new energy source that is environmentally-friendly and has improved energy efficiency in that it is possible to innovatively decrease use of fossil fuel, which is the primary advantage, while not generating a by-product when using energy.

The secondary battery applied to the EV or the energy storage source is typically used in a form, in which a plurality of unit secondary battery cells is combined, to improve adaptiveness to a high capacity environment, which, however, is not essentially applied to a case where the secondary battery is implemented as a battery of a portable terminal and the like.

When the battery, particularly, the plurality of secondary batteries alternately performs charging and discharging, it is necessary to manage the battery to maintain appropriate operation state and performance by efficiently controlling charging/discharging of the secondary batteries.

To this end, a battery management system (BMS) managing a state and performance of the battery is provided. The BMS may include a battery management controller (BMC) which includes a measuring device measuring a voltage, a current, a temperature, and the like of the battery, and a control device controlling operations of the battery and a switching device when it is diagnosed that the battery has a problem based on the measured value, and a battery disconnecting unit (BDU) which may disconnect the battery for protecting a load when it is diagnosed that the battery has a problem based on the measured value of the battery.

In the existing BMC, a measuring device connected to a battery side that is a high voltage part and a control unit controlling the battery based on the measured value are connected through one line, so that there are problems in that it is necessary to use an electronic component in which insulation is secured between the measuring device and the control unit, and insulation resistance between the measuring device and the control unit is decreased by the measuring device due to a high voltage. When the insulation resistance is decreased, interline short-circuit failure may be generated between the measuring device and the control unit, and reliability of the BMS is degraded.

Accordingly, it is necessary to provide a battery management system which stably drives a battery by solving the problem, such as the decrease in insulation resistance caused by the BMC positioned inside the BMS, and has reliability based on the stable driving of the battery.

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A secondary battery, which has high application easiness according to a product group and an electric characteristic, such as a high energy density, has been universally applied to an electric vehicle (EV) and a hybrid vehicle (HV) driven by an electric driving source, or an energy storage system (ESS), an uninterruptible power supply (UPS) system, or the like using a medium and large battery used for household or industry, as well as a portable device.

When the battery, particularly, the plurality of secondary batteries alternately performs charging and discharging, it is necessary to manage the battery to maintain appropriate operation state and performance by efficiently controlling charging/discharging.

A system for managing a battery according to the present invention is described in claim <NUM> and includes: one or more switches which connect a battery and a load; a voltage measuring unit which measures a voltage value of the battery; a control unit which controls the one or more switches based on the measured voltage value; and a communicating unit which transmits the measured voltage value to the control unit, in which the voltage measuring unit, the one or more switches, and the communicating unit are formed as a battery disconnecting unit (BDU), and the control unit is positioned outside the BDU.

The BDU is positioned at the battery side, and the control unit is positioned at the load side.

The system further includes a reference voltage generating unit which is connected with the battery in parallel and generates a reference voltage, in which the reference voltage generating unit generates a first reference voltage based on which overcharging of the battery is determined, and a second reference voltage based on which overdischarging of the battery is determined.

The control unit may include: a switch control unit which controls an operation of the switch; and a diagnosing unit which diagnoses a state of the battery based on the measured voltage value of the battery and the generated reference voltages.

The diagnosing unit may include a comparing unit which compares the voltage of the battery with the first reference voltage and the second reference voltage, and when the voltage of the battery is larger than the first reference voltage or the battery voltage is smaller than the second reference voltage, the diagnosing unit may output a switch control signal controlling the one or more switches.

The communicating unit further includes: : an insulating unit which electrically insulates the measured voltage value; and a transmitting unit which transmits the electrically insulated voltage value to the control unit.

The voltage measuring unit, the communicating unit, and the control unit may be connected to a controller area network (CAN) bus, so that the voltage measuring unit and the control unit may perform CAN communication.

According to one aspect of the present invention, it is possible to provide the battery management system, in which a voltage measuring unit and a control unit are separated in an existing battery management controller and the voltage measuring unit is included in the battery disconnecting unit, thereby preventing insulation resistance between the voltage measuring unit and the control unit from being decreased.

Further, it is possible to provide the battery management system, in which a voltage measured by the voltage measuring unit is electrically insulated and is provided to the control unit, thereby being applicable to a non-insulative low-cost electronic component, and decreasing noise and decreasing an analog measurement error due to the noise.

The present invention will be described below in detail with reference to the accompanying drawings. Herein, repeated descriptions and the detailed description of a publicly known function and configuration that may make the gist of the present invention unnecessarily ambiguous will be omitted. Exemplary embodiments of the present invention are provided so as to more completely explain the present invention to those skilled in the art. Accordingly, the shape, the size, etc., of elements in the figures may be exaggerated for more clear explanation.

Throughout the specification and the claims, unless explicitly described to the contrary, the word "include/comprise" and variations such as "includes/comprises" or "including/comprising" mean further including other constituent elements, not excluding the other constituent elements.

In addition, the term ". unit" described in the specification means a unit for processing at least one function and operation and may be implemented by hardware components or software components and combinations thereof.

<FIG> is a diagram schematically illustrating an electric vehicle to which a battery management system according to an exemplary embodiment of the present invention is applicable.

<FIG> illustrates an example, in which a battery management system <NUM> according to the exemplary embodiment of the present invention is applied to an electric vehicle <NUM>, but the battery management system <NUM> included in the exemplary embodiment of the present invention is applicable to any technical field, such as an energy storage system (ESS) for a house or an industry or an uninterruptible power supply (UPS) system, to which a secondary battery is applicable, in addition to the electric vehicle.

The electric vehicle <NUM> may include a battery <NUM>, a battery management system (BMS) <NUM>, an electronic control unit (ECU) <NUM>, an inverter <NUM>, and a motor <NUM>.

The battery <NUM> is an electric energy source for driving the electric vehicle <NUM> by providing driving force to the motor <NUM>. The battery <NUM> may be charged or discharged by the inverter <NUM> according to the driving of the motor <NUM> and/or an internal combustion engine (not illustrated).

Here, the kind of battery <NUM> is not particularly limited, and for example, the battery <NUM> may include a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel hydrogen battery, and a nickel zinc battery.

Further, the battery <NUM> is formed of a battery module, in which a plurality of battery cells is connected in series and/or in parallel, and a battery pack is formed of the plurality of battery modules. Further, the battery <NUM> may include one or more battery packs.

The BMS <NUM> estimates a state of the battery <NUM>, and manages the battery <NUM> by using information on the estimated state. For example, the BMS <NUM> estimates and manages state information of the battery <NUM>, such as a state of charging (SOC), a state of health (SOH), the amount of maximum input/output allowance power, and an output voltage of the battery. Further, the BMS <NUM> controls charging or discharging of the battery <NUM> by using the state information, and further, a replacement time of the battery <NUM> may be estimated.

The BMS <NUM> may be the battery management system <NUM> according to the exemplary embodiment of the present invention to be described below. Further, the BMS <NUM> may include the battery management system <NUM> according to the exemplary embodiment of the present invention or may be operated while being connected with the battery management system.

Similar to the battery management system <NUM>, in the BMS <NUM>, a measuring device measuring a current, a voltage, a temperature, and the like of the battery is separated from the control unit and the measuring device is included in a battery disconnecting unit including a switching unit so that it is possible to preventing insulation resistance between the measuring device and the control unit from being degraded and decrease an interline short-circuit and noise.

The ECU <NUM> is an electronic control device for controlling a state of the electric vehicle <NUM>. For example, the ECU <NUM> determines a torque level based on information about an accelerator, a brake, a speed, and the like, and controls an output of the motor <NUM> to correspond to torque information.

Further, the ECU <NUM> transmits a control signal to the inverter <NUM> so that the battery <NUM> is charged or discharged by the BMS <NUM>.

The inverter <NUM> makes the battery <NUM> be charged or discharged based on the control signal of the ECU <NUM>.

The motor <NUM> drives the electric vehicle <NUM> based on control information (for example, the torque information) transmitted from the ECU <NUM> by using electric energy of the battery <NUM>.

Hereinafter, the battery management system according to the exemplary embodiment of the present invention will be described with reference to <FIG> and <FIG>.

<FIG> is a diagram schematically illustrating the battery management system according to the exemplary embodiment of the present invention.

Referring to <FIG>, the battery management system according to the exemplary embodiment of the present invention may include a voltage measuring unit <NUM>, a switch <NUM>, a reference voltage generating unit <NUM>, a communicating unit <NUM>, and a control unit <NUM>.

The battery management system <NUM> illustrated in <FIG> is in accordance with the exemplary embodiment, and the constituent elements of the battery management system <NUM> are not limited to the exemplary embodiment illustrated in <FIG>, and the constituent elements may be added, changed, or deleted as necessary.

The voltage measuring unit <NUM> may measure a voltage value of the battery <NUM> module. For example, the voltage measuring unit <NUM> may measure a voltage of the battery <NUM> by measuring voltages applied to both ends of a shunt resistor serially connected with the battery <NUM>.

Herein, when the plurality of battery <NUM> modules is used in series or in parallel, one or more voltage measuring units may be included so as to measure one or more battery <NUM> modules, respectively, and one voltage measuring unit <NUM> may measure the plurality of battery modules <NUM> or the entire battery <NUM> modules.

The switch <NUM> may connect the battery <NUM> and a load, and when the control unit <NUM> to be described below diagnoses that the battery <NUM> module is in an abnormal state based on the voltage value measured by the voltage measuring unit <NUM>, the switch <NUM> may disconnect the battery <NUM> and the load by switching off the switch <NUM>.

One or more switches <NUM> may be provided in order to improve stability of the connection and the disconnection of the battery <NUM> module and the load, and the kind and the number of switches <NUM> may be determined according to a demand of a user, a required stability, and the like. For example, the switch <NUM> may be formed with one or more switching devices, such as a relay, a contactor, a transistor, and a thyristor.

The reference voltage generating unit <NUM> is connected with the battery <NUM> module in parallel and generate a reference voltage for diagnosing a state of the battery <NUM> module.

The reference voltage generating unit <NUM> generates a first reference voltage for diagnosing overcharging of the battery <NUM> module and a second reference voltage for diagnosing overdischarging of the battery <NUM> module, and the control unit <NUM> to be described below diagnoses a state of the battery <NUM> module based on the first reference voltage, the second reference voltage, and the voltage value of the battery <NUM> module measured by the voltage measuring unit <NUM>.

The communicating unit <NUM> may transmit the voltage value measured by the voltage measuring unit <NUM> to the control unit <NUM> to be described below, and to this end, the communicating unit <NUM> may include an insulating unit <NUM> and a transmitting unit <NUM>.

The insulating unit <NUM> electrically insulates the voltage measured by the voltage measuring unit <NUM> from the first and second reference voltages generated by the reference voltage generating unit <NUM>. For example, the insulating unit <NUM> may include a plurality of encoders and decoders. The voltage measured by the voltage measuring unit <NUM> and the first and second reference voltages may be encoded through the encoders and may be decoded through the decoders to be electrically insulated. The electrically insulated voltage value is transceived, thereby decreasing noise and decreasing an analog measurement error by the noise through the decrease in the noise.

The transmitting unit <NUM> may transmit the voltage value electrically insulated by the insulating unit <NUM> to the control unit <NUM> to be described below.

The control unit <NUM> may diagnose a state of the battery <NUM> module based on the insulated voltage value transmitted from the transmitting unit <NUM> and the first and second reference voltages generated by the reference voltage generating unit <NUM>. Further, the control unit <NUM> may control an on or off operation of one or more switches <NUM> according to a result of the diagnosis, and to this end, the control unit <NUM> may include a diagnosing unit <NUM> and a switch control unit <NUM>.

The diagnosing unit <NUM> may compare the voltage value of the battery <NUM> module measured by the voltage measuring unit <NUM> with the first and second reference voltages and diagnose a state of the battery <NUM> module. To this end, the diagnosing unit <NUM> may include a comparing unit (not illustrated) which compares the voltage of the battery <NUM> module with the first reference voltage and the second reference voltage.

The diagnosing unit <NUM> may compare the voltage of the battery <NUM> module with the first and second reference voltages through the comparing unit, and diagnose a state of the battery based on a result of the comparison. For example, when the measured voltage value of the battery <NUM> module is equal to or larger than the first reference voltage, the diagnosing unit <NUM> may diagnose that the battery <NUM> module is in an overcharging state, and when the measured voltage value of the battery <NUM> module is equal to or smaller than the second reference voltage, the diagnosing unit <NUM> may diagnose that the battery <NUM> module is in an overdischarging state. As described above, when the diagnosing unit <NUM> diagnoses that the battery is in the overcharging or overdischarging state, the diagnosing unit <NUM> may output a switch control signal operating the switch control unit <NUM> to be described below.

Herein, the switch control signal may be a signal switching on or off each of one or more switches or the plurality of switches.

When the switch control signal is output from the diagnosing unit <NUM>, the switch control unit <NUM> switches off one or more switches <NUM>, thereby disconnecting a load from the battery <NUM> module that is in the abnormal state and protecting the load.

<FIG> is a diagram schematically illustrating a configuration of the battery disconnecting unit in the battery management system according to the exemplary embodiment of the present invention.

Referring to <FIG>, the voltage measuring unit <NUM>, the one or more switches <NUM>, and the communicating unit <NUM> may be formed as one battery disconnecting unit <NUM>, and may be positioned at the battery <NUM> module side to which a high voltage is applied. Further, the control unit <NUM> may be positioned outside the battery disconnecting unit <NUM>, and may be positioned at a load side to which a low voltage is applied. Herein, the high voltage may be a direct-current voltage of <NUM> V and an alternating-current voltage of <NUM> V, and a voltage which is relatively lower than the high voltage may be referred to as a low voltage.

When the voltage measuring unit <NUM> is separated from the control unit <NUM>, and mutual information is exchanged through the communicating unit <NUM>, noise may be generated by various reasons, such as a distance among the voltage measuring unit <NUM>, the communicating unit <NUM>, and the control unit <NUM>, and the number of peripheral constituent elements, and a material of a peripheral constituent element, and the noise negatively influences an accurate analog measurement. In order to complement the problem, the voltage measuring unit <NUM>, the communicating unit <NUM>, and the control unit <NUM> may be connected through a controller area network (CAN) bus, and may exchange information through CAN communication through the connected CAN bus.

In the CAN communication, communication is performed so as to have an electric difference by using two lines, so that the CAN communication has advantages in being highly resistant to noise and being capable of performing communication up to a maximum of <NUM>,<NUM> with <NUM> kbps. Accordingly, the voltage measuring unit <NUM> and the control unit <NUM> may exchange information through the CAN communication, thereby decreasing an analog measurement error by noise and more accurately calculating a result value.

Hereinafter, a method of managing a battery through the battery management system according to an exemplary embodiment of the present invention will be described with reference to <FIG>.

<FIG> is a flowchart illustrating a method of managing a battery through the battery management system according to an exemplary embodiment of the present invention.

Referring to <FIG>, when a battery management method S100 by using the battery management system <NUM> starts, the voltage measuring unit measures a voltage of a battery module (S110), and the reference voltage generating unit generates first and second reference voltages (S120). Herein, the battery may be a battery cell, a battery module, or a battery pack according to various elements, such as a demand of a user and a use environment, and the first and second reference voltages may be adjusted according to the various elements.

The voltage value measured in operation S110 and the voltage values generated in operation S120 are electrically insulated through the insulating unit (S130), and the voltage value electrically insulated in operation S130 is transmitted to the control unit through the transmitting unit (S140). Operation S130 and operation S140 may be CAN communication, and the electrically insulated voltage value may be transmitted to the control unit through the CAN bus.

The diagnosing unit diagnoses a state of the battery based on the voltage value transmitted in operation S140 (S150). When the voltage value measured by the voltage measuring unit is equal to or larger than the first reference voltage or equal to or lower than the second reference value (S160), the diagnosing unit outputs a switch control signal for disconnecting the battery and a load (S170). When the diagnosing unit outputs the switch control signal, the switch is switched off to disconnect the battery and the load (S180), and when the diagnosing unit does not output the switch control signal, a normal operation is performed (S190).

The foregoing battery management method S100 by using the battery management system <NUM> has been described with reference to the flowchart presented in the drawing. For the simple description, the method is illustrated in a series of blocks and described, but it is not limited to the sequence of the blocks, and some blocks may be performed in a different order or at the same time as that of other blocks illustrated and described in the present specification, and other various branches, flow paths, and block sequences achieving the same or similar result may be carried out. Further, all of the blocks illustrated for carrying out the method described in the present specification may not be required.

Claim 1:
A system (<NUM>) for managing a battery, the system comprising:
one or more switches (<NUM>) configured to connect a battery (<NUM>) and a load (<NUM>);
a voltage measuring unit (<NUM>) configured to measure a voltage value of the battery;
a control unit (<NUM>) configured to control the one or more switches based on the measured voltage value; and
a communicating unit (<NUM>) configured to transmit the measured voltage value to the control unit;
a reference voltage generating unit (<NUM>) which is configured to be connected with the battery in parallel and is configured to generate a reference voltage,
wherein the voltage measuring unit, the one or more switches, and the communicating unit are formed as a battery disconnecting unit (<NUM>), BDU, and the control unit is positioned outside the BDU,
wherein the BDU is configured to be positioned at the battery side, and the control unit is configured to be positioned at the load side,
wherein the reference voltage generating unit is configured to generate a first reference voltage for diagnosing overcharging of the battery module and a second reference voltage for diagnosing overdischarging of the battery module;
wherein the control unit is configured to diagnose a state of the battery module based on the first reference voltage, the second reference voltage, and the voltage value of the battery module measured by the voltage measuring unit;
wherein the communicating unit further includes:
an insulating unit (<NUM>) configured to electrically insulate the measured voltage value from the first and second reference voltages generated by the reference voltage generating unit; and
a transmitting unit (<NUM>) configured to transmit the electrically insulated voltage value to the control unit.