Battery cell balancing control device and method therefor

Abstract

The present disclosure relates to a battery cell balancing control device and a method therefor, and the technical problem is to be solved by shortening the time required for balancing a battery cell. To this end, the present disclosure provides the battery cell balancing control device and the method therefor, the device comprising: a sensor for measuring voltages of a plurality of battery cells; a balancing circuit unit connected to each of the plurality of battery cells so as to discharge energy of the battery cells; and a processor for calculating individual states of charge (SOCs) of the plurality of battery cells on the basis of the voltages of the plurality of battery cells measured by the sensor, and controlling the balancing of the designated battery cells according to the SOCs and the voltage difference between the plurality of battery cells.

Description

Battery cell balancing control device and method

[0001] The present disclosure relates to a battery cell balancing control device and a method thereof that reduce the balancing time of a battery cell.

[0002] As electric vehicle-related technologies develop, the required battery voltage is increasing, and the number of battery packs is also increasing. Accordingly, the importance of balancing technology, which prevents overcharging and controls deviations between cells, is steadily increasing.

[0003] Battery cell balancing is the process of reducing deviations between battery cells while preventing overcharging of the battery cells. If sufficient time is not secured to perform the balancing operation, the balancing between battery cells will not be completed, and consequently, the battery will repeatedly charge and discharge without the voltage deviation being resolved.

[0004] If this condition persists, the battery may experience thermal runaway. If such thermal runaway occurs, it can not only cause a fire in the electric vehicle but also threaten the driver's life.

[0005] At this time, since balancing the battery cells takes a certain amount of time, there are cases where cell balancing is not completed until the engine is turned off. Accordingly, the balancing operation may continue to be performed even when the electric vehicle is in a parked state.

[0006] In cases where sufficient balancing time is not secured, the battery may continuously experience overcharging, the variation between cells may increase, and consequently, there is a problem of shortened battery cell lifespan.

[0007] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0008] The objective of the present invention is to provide a battery cell balancing control device and a method thereof that reduce the time required for balancing by performing balancing according to the state of charge (SOC) of the battery cell.

[0009] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0010] A battery cell balancing control device according to an embodiment of the present invention for solving the above technical problem comprises: a sensor for measuring the voltage of a plurality of battery cells; a balancing circuit unit connected to each of the plurality of battery cells to discharge the energy of the battery cells; and a processor that calculates an individual state of charge (SOC) for the plurality of battery cells based on the voltage of the plurality of battery cells measured by the sensor, and controls the balancing of a designated battery cell according to the state of charge and the voltage difference between the plurality of battery cells.

[0011] In the present invention, the balancing circuit comprises: a balancing resistor connected to a first battery cell among the plurality of battery cells to discharge the energy of the first battery cell; and a switch that operates according to a control signal of the processor to connect the balancing resistor to the first battery cell so that a balancing operation for the first battery cell is performed.

[0012] In the present invention, the balancing circuit is characterized by including first to n balancing circuits each connected to a first to n battery cell.

[0013] In the present invention, the processor sets a balancing duty according to the charging state and the voltage difference between the plurality of battery cells, and controls the balancing circuit based on the balancing duty to perform balancing for the battery cells.

[0014] In the present invention, the processor is characterized by setting the balancing duty so that the power consumption of the balancing circuit is greater than or equal to a certain value.

[0015] In the present invention, the processor resets the balancing duty for at least one of the cases where the voltage difference of the battery cell decreases and where the charge state changes, and controls the balancing of the battery cell according to the reset balancing duty.

[0016] In the present invention, the processor is characterized by increasing the balancing duty in proportion to the square of the decrease in the voltage difference of the battery cell when the voltage difference of the battery cell decreases.

[0017] In the present invention, the processor is characterized by resetting the balancing duty according to the state of charge (SOC) of a designated section in response to a change in the open circuit voltage according to the state of charge.

[0018] A battery cell balancing control method according to an embodiment of the present invention for solving the above technical problem comprises: a step in which a processor calculates an individual state of charge (SOC) for a plurality of battery cells based on a voltage for a plurality of battery cells measured by a sensor; a step in which the processor calculates a voltage difference between battery cells based on the voltage of the plurality of battery cells; and a step in which the processor performs balancing of a designated battery cell in correspondence with the state of charge and the voltage difference.

[0019] In the present invention, the step of performing balancing of the battery cell comprises: a step in which the processor sets a balancing duty according to the charge state and the voltage difference between the plurality of battery cells; a step in which the processor controls a balancing circuit connected to the battery cell based on the balancing duty; and a step in which the balancing circuit operates according to a control signal of the processor to discharge the energy of the battery cell.

[0020] In the present invention, the step of performing balancing of the battery cell further comprises: a step in which the processor resets the balancing duty for at least one of the case where the voltage difference of the battery cell decreases and the case where the charge state changes; and a step in which the processor controls the balancing of the battery cell according to the reset balancing duty.

[0021] In the step of performing balancing of the battery cell in the present invention, the processor is characterized by setting the balancing duty such that the power consumption of the balancing circuit is greater than or equal to a certain value.

[0022] In the step of resetting the balancing duty in the present invention, the processor is characterized by increasing the balancing duty in proportion to the square of the decrease in the voltage difference of the battery cell when the voltage difference of the battery cell decreases.

[0023] In the step of resetting the balancing duty in the present invention, the processor is characterized by resetting the balancing duty according to the state of charge (SOC) of a designated section in response to a change in the open circuit voltage according to the state of charge.

[0024] The step of performing balancing of the battery cell in the present invention comprises: a step in which the processor applies a control signal to a switch provided in the balancing circuit; and a step in which the switch conducts due to the control signal, thereby applying energy of the battery cell to a balancing resistor included in the balancing circuit so that the battery cell is discharged.

[0025] According to the present invention, the time required for balancing battery cells can be reduced by adjusting the duty cycle based on the voltage difference between battery cells based on the state of charge (SOC) of the battery cells.

[0026] In addition, according to the present invention, the heat generation of the battery cell can be minimized, and the duty cycle can be continuously changed according to the state of the battery cell to significantly improve balancing efficiency.

[0027] In addition, according to the present invention, the life of the battery can be increased.

[0028] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0030] FIG. 1 is a diagram showing the configuration of a battery pack according to an embodiment of the present invention.

[0031] FIG. 2 is a diagram briefly illustrating the configuration of a balancing circuit section for balancing a battery cell according to an embodiment of the present invention.

[0032] FIG. 3 is a block diagram briefly illustrating the control configuration of a balancing control device according to an embodiment of the present invention.

[0033] FIG. 4 is a figure showing the open circuit voltage according to the charge state of a battery cell according to an embodiment of the present invention.

[0034] FIG. 5 is a flowchart illustrating a battery cell balancing control method according to an embodiment of the present invention.

[0035] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor may appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; thus, various equivalents and modifications that can replace them may exist at the time of filing this application. Furthermore, as used in this specification, "comprise" or "include" and / or "comprising" or "including" specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups. In addition, when describing embodiments of the present invention, "can" and "can" may include "one or more embodiments of the present invention."

[0036] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0037] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0038] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0039] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0040] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0041] Furthermore, where it is stated that one component is "connected," "coupled," or "connected" to another component, it should be understood that while said components may be directly connected or connected to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "connected" through another component. Additionally, when it is stated that a part is electrically coupled with another part, this includes not only cases where they are directly connected but also cases where they are connected with another component in between.

[0042] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise. That is, "and / or" includes any combination or any combination of the enumerated items. "C to D" means C or more and D or less, unless specifically stated otherwise.

[0043] FIG. 1 is a diagram showing the configuration of a battery pack according to an embodiment of the present invention.

[0044] Referring to FIG. 1, a balancing control device according to an embodiment of the present invention may include a battery management device (BMS, Battery Management System) (100) that is provided in a battery pack including a plurality of battery cells (190) and controls a balancing operation for the battery cells.

[0045] A battery management device (BMS) (100) may include a balancing circuit section (150) including a balancing resistor that performs a balancing operation for a battery cell (190), an AFE IC (Analog Front End IC) (160), and a processor (110).

[0046] The balancing circuit (150) can adjust the voltage and state of charge (SOC) of the battery cells by adjusting the energy balance of the plurality of battery cells (190) during the balancing process. The balancing circuit (150) may be provided in multiple units and connected to each of the plurality of battery cells (190). The balancing circuit (150) may be connected to each end of the battery cell (190) to discharge the battery cell (190) and eliminate the voltage difference between the battery cells (190).

[0047] The AFE IC (Analog Front End IC) (160) processes at least one analog signal among voltage, current, and temperature for the battery cell (190) and can convert the analog signal into a digital signal.

[0048] The AFE IC (160) is connected to the balancing circuit (150) and can convert an analog signal input from the balancing circuit (150) into a digital signal and input it to the processor.

[0049] The processor (110) can process input / output data, monitor the state of the battery, and control balancing operations for the battery cells. Additionally, the processor (110) can diagnose defects in the battery cells (190) and control the transmission and reception of data. In some cases, the processor (110) may include an AFE IC (160).

[0050] FIG. 2 is a diagram briefly illustrating the configuration of a balancing circuit section for balancing a battery cell according to an embodiment of the present invention.

[0051] Referring to FIG. 2, the balancing circuit (150) may be connected to both ends of the battery cell (190), including a resistor (151) and a switch (152). The balancing circuit (150) may be connected to each battery cell among a plurality of battery cells (190).

[0052] The balancing circuit section (150) may be provided in the same number as the number of battery cells. For example, the first battery cell (191) may be connected to the first balancing circuit section. Additionally, the second battery cell may be connected to the second balancing circuit section, and the nth battery cell may be connected to the nth balancing circuit section.

[0053] At this time, the first balancing circuit may include a first balancing resistor (151) and a first switch (152) connected to the first battery cell (191).

[0054] The first balancing resistor (151) can discharge the first battery cell (191) by applying current from the first battery cell (191) depending on whether the switch (152) conducts. One end of the first balancing resistor (151) may be connected to one end of the first battery cell (191), and the other end may be connected to the switch (152).

[0055] The first switch (152) is connected to the first balancing resistor (151) and the other end is connected to the first battery cell (191), and operates according to a control signal from the processor (110).

[0056] The first switch (152) conducts according to a control signal of the processor (110) applied to the gate, and accordingly, the first battery cell (191) and the first balancing resistor (151) are connected. At this time, the current of the first battery cell (191) is applied to the first balancing resistor (151), thereby discharging the first battery cell (191).

[0057] The processor (110) can reduce the voltage difference with adjacent battery cells by controlling the first switch (152) to discharge the first battery cell (191) through the first balancing resistor (151). At this time, the processor (110) can reduce the voltage difference between battery cells by using a passive balancing method to consume the energy of the overcharged battery cell using the balancing resistor. In the case of passive balancing, the processor (110) can regulate the voltage of multiple battery cells by cutting off the charging current to the battery cell or changing the current flow to discharge it, while maintaining the supply of charging current to the uncharged battery cell.

[0058] The processor (110) can perform balancing for a plurality of battery cells (190) by controlling a balancing circuit connected to each of the plurality of battery cells (190). The processor (110) can calculate a voltage difference based on the voltage of the plurality of battery cells (190), select a balancing target among the plurality of battery cells (190) according to the voltage difference, and discharge the battery cell by applying a control signal to a switch connected to the battery cell.

[0059] FIG. 3 is a block diagram briefly illustrating the control configuration of a balancing control device according to an embodiment of the present invention.

[0060] Referring to FIG. 3, the balancing control device (100) may include a memory (120), a communication unit (130), a sensor (140), and a processor (110). Additionally, the balancing control device (100) may include a balancing circuit unit (150) and an AFE IC (160). At this time, the balancing control device (100) may be a battery management device (BMS) (100) or may include a battery management device (BMS).

[0061] The memory (120) can store sensor data regarding at least one of the voltage, current, temperature, and pressure of a battery cell input from a sensor (140), data regarding a plurality of cells (190), charging status data of a plurality of cells (190), and fault diagnosis data.

[0062] Additionally, the memory (120) may store data for at least one of a data analysis algorithm, a voltage difference calculation algorithm, a balancing control algorithm, a control signal generation algorithm, a battery cell monitoring algorithm, and a fault diagnosis algorithm for a plurality of battery cells (190). The memory (120) may include storage means such as non-volatile memory, flash memory, etc., such as RAM (Random Access Memory), ROM (ROM), EEPROM (Electrically Erased Programmable ROM).

[0063] The communication unit (130) can transmit and receive data according to the control command of the processor (110). The communication unit (130) can receive sensor data from the sensor (140) and transmit data to another device. For example, the communication unit (130) can communicate with the ECU of a vehicle equipped with a battery.

[0064] The communication unit (130) includes a plurality of communication modules and can transmit and receive data using at least one communication method among short-range communication such as Ethernet, Wi-Fi, and Bluetooth, mobile communication, CAN communication, LIN communication, and serial communication.

[0065] The sensor (140) may include at least one of a current sensor, a voltage sensor, a temperature sensor, and a pressure sensor.

[0066] For example, a current sensor can measure the charging current applied to a plurality of battery cells (190) and the discharge current of the plurality of battery cells (190). A voltage sensor can measure the voltage for each of the plurality of battery cells (190). A temperature sensor can measure the internal temperature of a battery pack containing a plurality of battery cells (190) depending on the location where it is installed, and can also be installed in each battery cell to measure the temperature of the battery cell. A pressure sensor can measure the internal pressure of a battery pack containing a plurality of battery cells (190).

[0067] The sensor (140) can input the measured sensor data to the processor (110). At this time, the AFE IC (160) can convert the analog data measured from the sensor (140) into digital data and input it to the processor (110).

[0068] The processor (110) may include at least one microprocessor and may operate based on data stored in memory (120). The processor (110) may be an MCU of a battery management device (BMS).

[0069] The processor (110) can calculate the voltage difference between battery cells based on the voltage of a plurality of battery cells (190) measured by the sensor (140), and control the balancing of the battery cells based on the voltage difference.

[0070] The processor (110) can calculate the State of Charge (SOC) for a plurality of battery cells (190) and store it in memory (120). The processor (110) can represent the State of Charge (SOC) as a percentage by dividing the remaining capacity of the battery cells by the total capacity of the battery cells.

[0071] For example, the processor (110) can calculate the current state of charge (SOC) based on the voltage of the battery cell and compared with the discharge curve for the battery cell. The processor (110) can calculate the state of charge (SOC) by measuring the voltage of the battery cell based on the open-circuit voltage in a stable state where no load is connected and calculating the remaining capacity of the battery cell.

[0072] Additionally, the processor (110) can calculate the current state of charge (SOC) by measuring the current of the battery cell using a Coulomb counting method (current integration method) and integrating it over time. At this time, the processor (110) can calculate the state of charge (SOC) at time t by dividing each current by the rated capacity of the battery cell and integrating it for time 0 to t, and subtracting the value accumulated from the initial SOC.

[0073] In some cases, the processor (110) may measure the state of charge (SOC) using the individual internal pressure of the battery cell.

[0074] For a plurality of battery cells (190), the processor (110) can calculate the charge state of each individual battery cell and the voltage difference between battery cells, and then set a balancing duty for the battery cells according to the charge state and the voltage difference. At this time, the processor (110) can set a balancing target based on the voltage difference of the battery cells.

[0075] The processor (110) can set the balancing duty differently for each battery cell (190) according to the state of charge (SOC) and voltage difference of each battery cell, thereby allowing the charging or discharging of each battery cell to be performed differently. Accordingly, the processor (1109) can reduce the time required for balancing compared to when balancing is performed with the same balancing duty and can improve the efficiency of balancing.

[0076] At this time, the processor (110) can control the balancing of the battery cells by applying a control signal to each switch according to the balancing duty to charge or discharge each battery cell.

[0077] The processor (110) can calculate the power consumption of the balancing resistor in correspondence with the balancing duty set differently for each battery cell. At this time, since the charged capacity of each battery cell is different, the state of charge (SOC) also appears differently.

[0078] When multiple battery cells (190) are charged or discharged simultaneously, the balancing duty is set differently for each battery cell's SOC, so a difference in cell voltage may occur during balancing.

[0079] At this time, the balancing resistor (R) is designed to operate at maximum balancing power. Accordingly, the power consumption of the balancing resistor (R) described above can be calculated by dividing the square of the voltage of the battery cell connected to the balancing resistor (R) by the size of the balancing resistor and then multiplying by the balancing duty. That is, the power consumption of the balancing resistor (R) can be proportional to the square of the voltage of the battery cell.

[0080] The processor (110) can calculate the power consumption of the balancing resistor connected to the battery cell as shown in the following mathematical formula 1.

[0081]

[0082] At this time, V is the voltage of the battery cell, R is the size of the balancing resistor connected to the battery cell, and Duty is the balancing duty that is set differently depending on the state of charge (SOC) of the battery cell.

[0083] Since the state of charge (SOC) of the battery cell decreases by the amount of power consumed by the balancing resistor, the processor (110) can reset the balancing duty by taking into account the decrease in the voltage difference between the battery cells. At this time, since the power consumption also decreases as the voltage difference between the battery cells decreases, the processor (110) can increase the balancing duty in proportion to the square of the decrease in the voltage difference.

[0084] The processor (110) can variably control the balancing duty according to the state of charge (SOC) in a certain section where the balancing efficiency is low, based on the characteristic curve of the state of charge and open circuit voltage.

[0085] The processor (110) can reduce the time required for balancing the battery cells by continuously changing the balancing duty, taking into account the decrease in the voltage difference between the battery cells during the balancing process. When the processor (110) performs balancing for the battery cells with the same balancing duty, the power consumed by the balancing resistor also decreases as the voltage difference decreases, so the discharge amount per hour decreases. Accordingly, the processor (110) can perform balancing faster than with a fixed balancing duty by increasing the balancing duty, taking into account the decrease in the voltage difference caused by balancing the battery cells.

[0086] FIG. 4 is a figure showing the open circuit voltage according to the charge state of a battery cell according to an embodiment of the present invention.

[0087] Referring to FIG. 4, the open circuit voltage (OCV) according to the charge state of the battery cell may vary depending on the charge state of the battery cell. At this time, the first line (L1) and the third line (L3) represent the change in open circuit voltage (OCV) according to the charge state (SOC) of the battery cell during charging, and the second line (L2) and the fourth line (L4) represent the change in open circuit voltage (OCV) according to the charge state (SOC) of the battery cell during discharging.

[0088] As illustrated in the drawing, the open circuit voltage (OCV) according to the state of charge (SOC) of the battery cell is not linear with respect to the state of charge (SOC).

[0089] The voltage difference between battery cells to be balanced varies depending on the state of charge and is not linear, and the heat generated by the balancing resistor varies depending on the state of charge (SOC), so inefficient sections may occur during balancing.

[0090] When the state of charge (SOC) of the battery cell is in the first section (A), that is, when the state of charge (SOC) is below a set value, even if the state of charge (SOC) changes significantly, the open circuit voltage does not change significantly and the magnitude of the open circuit voltage can be measured as small. Accordingly, the power consumption of the balancing resistor can be calculated as a low value below a certain value.

[0091] When the state of charge (SOC) of the battery cell is in the second section (B), that is, when the state of charge (SOC) is greater than the set value, the magnitude of the open circuit voltage (OCV) can be measured as large depending on the change in the state of charge (SOC) of the battery cell. Therefore, the power consumption of the balancing resistor can be calculated as a high value.

[0092] In other words, as the value of the state of charge (SOC) of the battery cell decreases, the magnitude of the open-circuit voltage decreases, and thus the power consumption of the balancing resistor also decreases; and as the value of the state of charge of the battery cell increases, the magnitude of the open-circuit voltage increases, and thus the power consumption of the balancing resistor also increases.

[0093] Since the power consumption of the balancing resistor is proportional to the square of the voltage as in Equation 1 explained above, the power consumption of the balancing resistor decreases as the charge state decreases, so the processor (110) needs to increase the balancing duty.

[0094] Accordingly, the processor (110) can set the balancing duty according to the state of charge (SOC) of the battery cells as well as the voltage difference between the battery cells. In addition, the processor (110) can control the balancing of the battery cells by continuously changing the balancing duty in consideration of changes in the state of charge of the battery cells or a decrease in the voltage difference between the battery cells. At this time, the processor (110) can change the balancing duty in the same way as in the case of discharge as well as charging.

[0095] The processor (110) can control balancing by continuously changing the balancing duty according to the charge state of the battery cell, so that the balancing operation for the battery cell is performed quickly as the power consumption of the balancing resistor is maintained above a certain value.

[0096] FIG. 5 is a flowchart illustrating a battery cell balancing control method according to an embodiment of the present invention.

[0097] Referring to FIG. 5, the processor (110) measures the voltage of the battery cell (190) through the sensor (140) (S310). The processor (110) calculates the voltage difference between the battery cells based on the voltages of the multiple battery cells (190) being measured (S320).

[0098] At this time, the processor (110) may set a battery in which the voltage difference between battery cells is greater than or equal to a set value as a balancing target. Additionally, the processor (110) may set all of a plurality of battery cells as balancing targets.

[0099] The processor (110) calculates the individual state of charge (SOC) for each battery cell based on the voltage or current of the battery cell. For example, the processor (110) can calculate the state of charge (SOC) according to voltage using a discharge curve or calculate the state of charge (SOC) of the battery cell using a current calculation method.

[0100] The processor (110) can set a balancing duty based on the voltage difference between battery cells and the state of charge (SOC) (S330). The processor (110) can set a balancing duty such that the power consumption of the balancing resistor in the balancing circuit that discharges the energy of the battery cells is greater than or equal to a certain value. When the state of charge (SOC) of the battery cells is lower than the set value, the magnitude of the corresponding open circuit voltage also becomes smaller than the set voltage, so the power consumption required for balancing is reduced. When the state of charge (SOC) of the battery cells is lower than the set value or when the voltage is lower than the set voltage, the processor (110) can increase the balancing duty to increase power consumption, thereby shortening the time required for balancing.

[0101] The processor (110) performs balancing on the battery cells according to the set balancing duty (S340). The processor (110) applies a control signal to the switch of the balancing circuit unit (150) so that the energy of the battery cells is discharged by the balancing resistor. In addition, the processor (110) may charge the battery cells by applying a charging current to the battery cells that require charging.

[0102] The processor (110) measures the voltage of the battery cell from the sensor (140) during balancing and calculates the state of charge (SOC) of the battery cell to determine whether the voltage difference between the battery cells decreases (S350). For example, the processor (110) may determine whether the amount of decrease in the voltage difference exceeds a voltage decrease setting value, or whether the amount of change in the state of charge of the battery cell exceeds a state of charge setting value.

[0103] The processor (110) maintains balancing for the battery cells with the current balancing duty when the voltage difference does not decrease (S340).

[0104] Meanwhile, the processor (110) determines whether balancing is complete when the voltage difference is reduced (S360). At this time, the processor (110) may determine that the voltage difference has been reduced in either case where the amount of reduction in the voltage difference exceeds the voltage reduction setting value, or where the amount of change in the charge state exceeds the charge state setting value.

[0105] The processor (110) resets the balancing duty according to the reduced voltage difference and the charge state of the battery cell when the voltage difference is reduced and when the balancing of the battery cell is not completed. The processor (110) can change the balancing duty whenever the voltage difference is reduced while performing balancing for the battery cell.

[0106] When the voltage difference decreases, the processor (110) can increase the balancing duty to maintain or increase the power consumption of the balancing resistor, as the power consumption in the balancing resistor decreases in proportion to the square of the change in the magnitude of the voltage. Accordingly, the processor (110) can complete the balancing of the battery cell more quickly.

[0107] The processor (110) performs balancing for the battery cells based on the changed balancing duty (S340).

[0108] The processor (110) terminates balancing for the battery cell when the voltage difference decreases and balancing is completed (S370).

[0109] As such, according to the present invention, the time required for balancing battery cells can be shortened by adjusting the balancing duty based on the voltage difference between battery cells based on the state of charge (SOC) of the battery cells.

[0110] In addition, according to the present invention, heat generation of the battery cell can be minimized, and the balancing duty can be continuously changed according to the state of the battery cell to significantly improve balancing efficiency.

[0111] In addition, according to the present invention, the lifespan of the battery can be increased by improving the balancing efficiency.

[0112] The implementations described herein may be implemented, for example, as methods or processes, devices, software programs, data streams, or signals. Even if discussed only in the context of a single form of implementation (e.g., discussed only as a method), the implementation of the discussed features may also be implemented in other forms (e.g., devices or programs). Devices may be implemented in appropriate hardware, software, and firmware, etc. Methods may be implemented in devices such as processors, which generally refer to processing devices including, for example, computers, microprocessors, integrated circuits, or programmable logic devices. Processors also include communication devices such as computers, cell phones, portable / personal digital assistants ("PDAs"), and other devices that facilitate the communication of information between end-users.

[0113] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. A sensor for measuring the voltage of multiple battery cells; A balancing circuit unit connected to each of the plurality of battery cells to discharge the energy of the battery cells; and A battery cell balancing control device characterized by comprising: a processor that calculates an individual state of charge (SOC) for a plurality of battery cells based on the voltage for the plurality of battery cells measured by the sensor, and controls the balancing of a designated battery cell according to the state of charge and the voltage difference between the plurality of battery cells.

2. In Paragraph 1, The balancing circuit comprises: a balancing resistor connected to a first battery cell among the plurality of battery cells to discharge the energy of the first battery cell; and A battery cell balancing control device characterized by including: a switch that operates according to a control signal of the above processor to connect the balancing resistor to the first battery cell so that a balancing operation for the first battery cell is performed.

3. In Paragraph 1, A battery cell balancing control device characterized in that the balancing circuit section comprises a first to n balancing circuit section connected to each of the first to n battery cells.

4. In Paragraph 1, A battery cell balancing control device characterized by the processor setting a balancing duty based on the charge state and the voltage difference between the plurality of battery cells, and controlling the balancing circuit based on the balancing duty to perform balancing for the battery cells.

5. In Paragraph 4, A battery cell balancing control device characterized by the processor setting the balancing duty such that the power consumption of the balancing circuit is greater than or equal to a certain value.

6. In Paragraph 4, A battery cell balancing control device characterized by the processor resetting the balancing duty for at least one of the cases where the voltage difference of the battery cell decreases and where the charge state changes, and controlling the balancing of the battery cell according to the reset balancing duty.

7. In Paragraph 6, A battery cell balancing control device characterized by the processor increasing the balancing duty in proportion to the square of the decrease in the voltage difference of the battery cell when the voltage difference of the battery cell decreases.

8. In Paragraph 7, A battery cell balancing control device characterized by the processor resetting the balancing duty according to the state of charge (SOC) of a designated section in response to a change in the open circuit voltage according to the state of charge.

9. A step in which a processor calculates an individual state of charge (SOC) for a plurality of battery cells based on the voltage for the plurality of battery cells measured by a sensor; The above processor calculates a voltage difference between battery cells according to the voltage of the plurality of battery cells; and A battery cell balancing control method characterized by including the step of the processor performing balancing of a designated battery cell in response to the charge state and the voltage difference.

10. In Paragraph 9, The step of performing balancing of the above battery cells is, A step in which the processor sets a balancing duty according to the charge state and the voltage difference between the plurality of battery cells; The step of the processor controlling a balancing circuit connected to the battery cell based on the balancing duty; and A battery cell balancing control method characterized by including the step of the balancing circuit operating according to a control signal of the processor to discharge the energy of the battery cell.

11. In Paragraph 10, The step of performing balancing of the above battery cells is, For at least one of the case where the voltage difference of the battery cell decreases and the case where the charge state changes, the processor resets the balancing duty; and A battery cell balancing control method characterized by further including the step of the processor controlling balancing for the battery cell according to the reset balancing duty.

12. In Paragraph 11, In the step of performing balancing of the above battery cells, A battery cell balancing control method characterized by the processor setting the balancing duty such that the power consumption of the balancing circuit is greater than or equal to a certain value.

13. In Paragraph 11, In the step of resetting the balancing duty mentioned above, A battery cell balancing control method characterized by the processor increasing the balancing duty in proportion to the square of the decrease in the voltage difference of the battery cell when the voltage difference of the battery cell decreases.

14. In Paragraph 11, In the step of resetting the balancing duty mentioned above, A battery cell balancing control method characterized by the processor resetting the balancing duty according to the state of charge (SOC) of a designated section in response to a change in the open circuit voltage according to the state of charge.

15. In Paragraph 11, The step of performing balancing of the above battery cells is, The step of the processor applying a control signal to a switch provided in the balancing circuit; and A battery cell balancing control method characterized by including the step of: the switch conducting by the above control signal, so that the energy of the battery cell is applied to the balancing resistor included in the balancing circuit, thereby discharging the battery cell.

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