WO2019074220A1 - Battery capacity estimation apparatus and method, and battery management apparatus provided with same and method thereof - Google Patents

Abstract

The present invention provides a battery capacity estimation apparatus and method, and a battery management apparatus provided with the same and a method thereof, the battery capacity estimation apparatus comprising: a battery; a sensing unit connected to the battery so as to measure an OCV of the battery; a SOC estimation unit connected to the sensing unit so as to estimate an initial SOC of the battery by using the OCV measured by the sensing unit; a memory unit which stores data including a SOC and an OCV of the battery and is connected to the SOC estimation unit; and a calculation unit which is connected to the SOC estimation unit and the memory unit, calculates a SOC reduction level according to a range change of a used voltage, and recalculates a changed SOC according to a changed use capacity.

Description

Apparatus and method for estimating the capacity of a battery, and a battery management apparatus and method using the same

The present invention relates to an apparatus and method for estimating a capacity of a battery, and more particularly, to an apparatus and method for estimating a capacity of a battery according to a reduction in a range of voltage used.

2. Description of the Related Art In recent years, demand for portable electronic products such as notebooks, portable phones, and the like has been rapidly increasing, and studies have been actively conducted on high performance secondary batteries (hereinafter referred to as batteries) capable of repeated charging and discharging. Nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries are currently commercially available batteries. Among them, lithium batteries have little memory effect compared with nickel-based batteries, Low energy density and high energy density.

On the other hand, as carbon energy is gradually depleted and environmental concerns are increasing, demand for hybrid cars and electric vehicles is increasing. Since such hybrid vehicles and electric vehicles use the charge / discharge energy of the battery pack to obtain the vehicle driving power, they are more fuel-efficient than the vehicles using only the engine and can not discharge or reduce pollutants. . Therefore, more attention and research are focused on automotive batteries, which are key components of hybrid cars and electric vehicles.

Batteries are time consuming because they are used in portable devices without an external power source such as AC power. However, if the usable time of the battery, that is, the available time, can not be predicted properly, the user may experience a great difficulty. For example, if the battery life of an electric vehicle can not be accurately predicted, the battery may be discharged during operation, causing the vehicle to halt in the middle of the road.

In order to prevent the battery from suddenly discharging during the use of the battery due to the inability to predict the full discharge of the battery, a technology for estimating the residual amount of the battery, that is, the state of charge (SOC) and providing it to the user is widely known. The SOC of the battery is generally expressed as a percentage of the remaining capacity of the battery with respect to the full charge capacity (FCC). As a method of estimating the SOC of the battery, various methods can be used. A representative method is a method of estimating the SOC using the current integration method. In this current integration method, the SOC is obtained by integrating the input / output current of the battery and adding / subtracting it from the initial capacity.

On the other hand, when a battery pack is mounted on an automobile or the like, an automobile manufacturer can change the usable voltage range in consideration of the life and stability of the battery. For example, the available voltage range can be reduced from a minimum of 2.4V to a maximum of 4.0V for a battery capable of operating from a minimum of 2.0V to a maximum of 4.2V. However, as the voltage range decreases, the SOC can not be reflected in the FCC calculation algorithm even though the usable capacity decreases. That is, the initial residual amount estimation is not performed due to the reduction in the use range, which causes a larger error as time passes.

(Prior art document)

Korean Patent Publication No. 2014-0053590

The present invention provides a battery capacity estimating apparatus and method capable of estimating a capacity of a battery according to a change in a voltage range to be used, and a battery management apparatus and method having the same.

The present invention provides a battery capacity estimation apparatus and method capable of estimating a capacity according to a reduced use voltage range using an initial capacity estimation using an OCV table, and a battery management apparatus and method therefor.

A battery capacity estimating apparatus according to a first aspect of the present invention includes: a battery; A sensing unit connected to the battery to measure OCV of the battery; An SOC estimator connected to the sensing unit and estimating the SOC of the battery using the OCV measured from the sensing unit; A memory unit for storing data including SOC and OCV of the battery and connected to the SOC estimating unit; And an operation unit connected to the SOC estimating unit and the memory unit, for calculating the degree of SOC reduction according to the range of the operating voltage, and for outputting the changed SOC according to the changed used capacity.

The memory unit stores and stores a plurality of initial SOCs and a plurality of initial OCVs, and stores a plurality of changed SOCs and a plurality of changed OCVs.

The calculation unit calculates the capacity changed by the following equation (1).

[Equation 1]

Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.

The operation unit calculates the changed SOC using Equation (2) below.

&Quot; (2) "

Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.

A battery management apparatus according to a second aspect of the present invention includes a battery; A sensing unit connected to the battery to measure OCV of the battery; An SOC estimator connected to the sensing unit and estimating the SOC of the battery using the OCV measured from the sensing unit; A memory unit for storing data including SOC and OCV of the battery and connected to the SOC estimating unit; A calculating unit connected to the SOC estimating unit and the memory unit, for calculating a degree of SOC reduction according to a change in the operating voltage range and for outputting a changed SOC according to the changed used capacity; A control unit connected to at least one of the operation unit and the memory unit to control charging and discharging of the battery according to the state of the battery by referring to the SOC; And a switching unit provided between the battery and the load for charging / discharging the battery according to a control signal of the control unit.

The calculation unit calculates the changed capacity by the following equation (1), and calculates the changed SOC using the following equation (2).

[Equation 1]

Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.

&Quot; (2) "

Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.

A method of estimating a capacity of a battery according to a third aspect of the present invention includes: a step of measuring OCV of a battery; Estimating an initial SOC according to the measured OCV; Calculating the SOC reduction degree according to the use voltage range change and calculating the changed SOC; And calculating a changed OCV according to the changed SOC.

And a step of matching and storing a plurality of initial SOCs of the battery and a plurality of initial OCVs corresponding thereto.

The initial SOC is estimated by matching the measured OCV with the initial OCV.

The step of calculating the changed SOC may include calculating a degree of SOC change according to the use voltage range change, calculating a changed capacity by subtracting the SOC from the initial capacity, and calculating the changed SOC do.

The changed capacity is calculated by the following equation (1).

[Equation 1]

Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.

The modified SOC is calculated using the following equation (2).

&Quot; (2) "

Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.

And storing the plurality of data by matching the changed SOC and the changed OCV.

A battery management method according to a fourth aspect of the present invention includes the steps of: measuring OCV of a battery; Estimating an initial SOC according to the measured OCV; Calculating the SOC reduction degree according to the use voltage range change and calculating the changed SOC; Calculating a changed OCV according to the changed SOC; And controlling the charge / discharge of the battery according to the state of the battery with reference to the changed SOC.

The step of calculating the changed SOC may include calculating a degree of SOC change according to the use voltage range change, calculating a changed capacity by subtracting the SOC from the initial capacity, and calculating the changed SOC do.

The modified capacity is calculated by the following equation (1), and the modified SOC is calculated using the following equation (2).

[Equation 1]

Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.

&Quot; (2) "

Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.

The embodiments of the present invention can estimate the SOC and the capacity of the battery pack whose operating voltage range has been changed by using the OCV table according to the needs of the manufacturer mounting the battery in an automobile or the like. For example, the range of the operating voltage may be changed according to the manufacturer's request for the battery pack whose manufacture range of the battery pack is completed and the operating voltage range is set. In this case, the present SOC is calculated with reference to the OCV table, Calculate the degree of SOC reduction by referring to the OCV table for the upper and lower ranges of the use range, calculate the FCC capacity by deducting the SOC reduction amount, and calculate a new SOC according to the reduced use range. By estimating the changed SOC according to the reduction of the voltage range as described above, it is possible to prevent the occurrence of an error, thereby enabling stable use of the battery.

1 is a schematic block diagram of an electric vehicle to which SOC estimation of a battery according to embodiments of the present invention is applied;

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

3 is a diagram illustrating an example of an initial OCV table used in a SOC estimation method of a battery according to an embodiment of the present invention;

4 is a diagram illustrating an OCV table changed according to a voltage range reduced by a SOC estimation method of a battery according to an embodiment of the present invention;

5 is a schematic view for explaining a SOC estimation method of a battery according to an embodiment of the present invention;

6 is a graph comparing data of the initial OCV table and the changed OCV table.

7 and 8 are block diagrams of a battery management apparatus according to an embodiment of the present invention.

FIG. 9 is a schematic view for explaining a SOC estimation method of a battery according to an embodiment of the present invention; FIG.

10 is a flowchart of a SOC estimation method of a battery according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

1 is a schematic block diagram of an electric vehicle in which SOC estimation of a battery according to an embodiment of the present invention is used.

1, an electric vehicle includes a battery 10 that provides electric energy, a BMS 20 that manages the battery 10, an ECU 30 that controls the state of the electric vehicle, An inverter 40 for driving the motor 50 so as to enable the motor 50, and a motor 50 for driving the electric vehicle.

The battery 10 is an electric energy source that drives the electric vehicle 1 by providing a driving force to the motor 50. [ The battery 10 can be charged or discharged by the inverter 40 in accordance with the driving of the motor 50 and / or the internal combustion engine (not shown). Here, the battery 10 may include at least one battery pack, each of the at least one patty pack may include a plurality of battery modules, and the battery module may include a plurality of charge and discharge battery cells . The plurality of battery modules may be connected in series and / or in parallel in various ways to meet specifications of a vehicle, a battery pack, etc., and a plurality of battery cells may also be connected in series and / or in parallel. Here, the type of the battery cell is not particularly limited and may be a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel hydride battery, a nickel zinc battery, or the like.

The BMS 20 estimates the state of the battery 10 and manages the battery 10 using the estimated state information. For example, it estimates and manages the state information of the battery 10 such as the SOC, the State of Health (SOH), the maximum input / output power allowable amount, and the output voltage of the battery 10. Then, the charging or discharging of the battery 10 is controlled using this state information. The BMS 20 according to the present invention includes an SOC estimating device for estimating an SOC of a battery. In addition, the BMS 20 controls cell balancing to balance the state of charge of each battery cell. That is, a battery cell having a relatively high charging state is discharged, and a battery cell having a relatively low charging state can be charged.

An engine controller unit (ECU) 30 is an electronic control unit for controlling the state of an electric vehicle. For example, it determines the degree of torque based on information such as an accelerator, a break, and a speed, and controls the output of the motor 50 to match the torque information. The ECU 30 also allows the battery 10 to be charged or discharged based on status information of the SOC, SOH, etc. of the battery 10 transmitted by the BMS 20. [ For example, when the SOC delivered from the BMS 20 is 55% or less, the switch of the inverter 40 is controlled to output power in the direction of the battery 10 to charge the battery 10, The switch of the inverter 40 is controlled so that electric power is output in the direction of the motor 50 to discharge the battery 10.

The inverter (40) drives the motor (50) so that the electric vehicle can run on the basis of the control signal of the ECU (30).

The motor 50 drives the electric vehicle 1 based on control information (for example, torque information) transmitted from the ECU 30 using the electric energy of the battery 10.

2 is a block diagram illustrating a configuration of an SOC estimating apparatus for a battery according to an embodiment of the present invention. That is, FIG. 2 is a block diagram of an apparatus for estimating an initial SOC of a battery and estimating a changed SOC according to a reduction of a voltage range of a user. 3 and 4 are views showing an example of an OCV table used in an embodiment of the present invention. FIG. 3 is an exemplary view of an initial OCV table. FIG. Lt; RTI ID = 0.0 > OCV < / RTI > 5 is a schematic diagram for explaining a method of estimating SOC of a battery according to an embodiment of the present invention. Meanwhile, FIG. 6 is a graph comparing the initial OCV table and the changed OCV table data.

2, an apparatus for estimating SOC of a battery according to an embodiment of the present invention includes a sensing unit 100 for sensing voltage and current of a battery 10, an SOC estimating unit 200 for estimating SOC of a battery A memory unit 300 for storing data such as the SOC and voltage of the battery 10; a calculation unit 400 for calculating the degree of SOC reduction due to the change of the voltage range for use and for outputting the SOC according to the reduced usage range; . ≪ / RTI >

First, the battery 10 may include a plurality of battery cells 11, 12, 13, ..., 1n that can be charged and discharged. Here, the battery 10 may be connected to an even number of battery cells or to an odd number of battery cells. That is, n may be an even number or an odd number. In addition, a plurality of battery cells may be connected in series. That is, a plurality of battery cells have one terminal and another terminal, and one terminal of one battery cell may be connected to the other terminal of another battery cell. For example, the cathode of the first battery cell 11 may be connected to the anode of the second battery cell 12, and the cathode of the second battery cell 12 may be connected to the anode of the third battery cell 13. [ have. In addition, the plurality of battery cells may have the same capacity, and thus the maximum charging voltage may be the same, for example, the maximum charging voltage may be 4.2V.

1. Sensing unit

The sensing unit 100 is provided for sensing the state of the battery 10 and senses the voltage and current of the battery 10, for example. Here, the sensing unit 100 may sense voltage and current of the battery pack, the battery module, and the battery cell. For this, the sensor unit 100 may include a plurality of sensors, for example, at least one voltage sensor (not shown) and at least one current sensor (not shown). The voltage sensor can measure the voltage of at least one of the battery pack, the battery module or the battery cell. For example, a voltage sensor can be used to measure the voltage of a battery pack, which can measure a stabilized voltage, or OCV, after a predetermined time from the battery pack after the BMS is enabled. The current sensor can measure the current in the battery pack. The current sensor may include a Hall current transformer (Hall CT) that measures current using, for example, a Hall element and outputs a signal corresponding to the measured current. Meanwhile, the sensing unit 110 may further include a battery 10 or a temperature sensor (not shown) for measuring the ambient temperature. The temperature sensor can measure the temperature of one area or a plurality of areas of the battery pack or the battery module, and at least one temperature sensor can be provided for this purpose. 2, the sensing unit 100 may be connected to the battery 10 through a plurality of connection lines to sense voltage, current, temperature, and the like of the battery 10 using the sensing unit 100. [ have. For example, each of the plurality of battery cells 11, 12, 13, 14, ..., 1n may be connected to the sensing unit 100 through a plurality of connection lines. For example, the positive electrode of the first battery cell 11 and the sensing unit 100 are connected through a connection line, and the first battery cell 11 and the second battery cell 12 are connected through a connection line And may be connected to the sensing unit 100. Each of the plurality of battery cells 11, 12, 13, 14, ..., 1n connected in series is connected to the sensing unit 100 through a connection line, ..., 1n can be sensed by the sensing unit 100. [

2. SOC estimation section

The SOC estimating unit 200 estimates the SOC of the battery 10. There are various ways to estimate the SOC. The SOC of the battery 10 can be estimated using the capacity of the battery 10 estimated from the SOH estimation unit (not shown) and the current of the battery 10 measured from the sensing unit 100, for example. That is, the SOC estimating unit 200 estimates the SOC of the battery 10 by integrating the current value measured for the predetermined time from the sensing unit 100 and dividing the current value by the estimated battery capacity (Capacity) from the SOH estimating unit . Also, the SOC estimating unit 200 can estimate the SOC using the OCV (Open Circuit Voltage) of the battery 10. [ That is, the SOC can be estimated by referring to the initial OCV table stored in the memory unit 300, and extracting the SOC matched to the OCV measured by the sensing unit 100. For example, if the OCV measured from the sensing unit 100 is 3560 mV, it can be estimated that the SOC is 40% by referring to the OCV table of FIG. The SOC estimating unit 200 can estimate the SOC by various methods such as measuring the impedance of the battery 10 and estimating the SOC. The embodiment of the present invention estimates the SOC by matching the OCV measured from the sensing unit 100 with the OCV table stored in the memory unit 300.

3. Memory section

The memory unit 300 may store various data for operating the battery 10. In particular, the memory unit 300 may store the SOC and the OCV. At this time, the SOC and the OCV can be matched and stored. That is, various experimentally measured SOCs and corresponding OCVs may be stored in the memory unit 300. For example, as shown in FIG. 3, SOCs ranging from 0% to 100% and OCVs according to respective SOCs can be measured, and they can be matched and stored. The SOC and OCV stored in the memory unit 300 can be measured and stored in various ways. For example, the battery cell of the same specification as the battery cell used as the battery 10 of the present invention is charged from 0.5 V to 4.2 V, for example, from 3 V to 50 mA cutoff, , And measures the voltage of the battery cell periodically during discharging. This process is repeated a plurality of times, for example, 7 to 8 times, so that the SOC and OCV averages are calculated to provide the SOC and OCV tables. Alternatively, the charge OCV is periodically measured while the battery cell is charged to 0.001C (i.e., charged for 1000 hours), and the discharge COV is periodically measured while discharging to 0.001C (i.e., discharging for 1000 hours) And the discharge OCV are calculated, and the SOC and the OCV table can be prepared by calculating the SOC at this time. Alternatively, the cylindrical battery cell is fully secured using a mechanical fixture and the screw is used to contact the + and - terminals of the charger and loader and the + and - terminals of the cylindrical battery cell. A plurality of structures in which the battery cell is in contact with the charger and the loader are manufactured and placed in a thermo-hygrostat chamber to extract SOC and OCV at a constant temperature. On the other hand, COV and SOC are matched and stored, and the temperature and internal resistance at this time can also be stored. That is, the memory unit 300 may be previously stored by separately obtaining a capacity decrease coefficient depending on the ambient temperature of the battery, the internal resistance, or the temperature. In addition, the memory unit 300 may store the newly corrected OCV and SOC according to the change in the range of the voltage used. For example, as shown in FIG. 4, the newly estimated SOC and the corresponding OCV may be matched and stored according to the reduction of the operating voltage range. At this time, the newly corrected OCV table may be stored by updating the initial OCV table or may be stored separately from the initial OCV table. That is, newly calculated SOC and OCV data may be overwritten and stored in the initial OCV table, or a new OCV table may be stored as data separate from the initial OCV table. Meanwhile, the memory unit 300 may be provided in the BMS 20, and may be separately provided in addition to the BMS 20. The memory unit 300 may be a hard disk drive, a flash memory, an electrically erasable programmable read-only memory (EEPROM), a static random access memory (SRAM), a ferro-electric random access memory (FRAM), a phase change random access memory (PRAM) ) And the like can be used.

4. Operation unit

The operation unit 400 calculates the degree of SOC reduction according to the range of the use voltage and re-calculates the SOC according to the calculated degree of decrease. To this end, the operation unit 400 calculates the degree of SOC reduction using the upper and lower ranges of the operating voltage range according to the range of the operating voltage range. That is, the operation unit 400 detects the upper and lower ranges of the operating voltage range by referring to the initial OCV table of the memory unit 300, and calculates the degree of SOC reduction according to the detected OCV table. For example, when the operating voltage range is from 4.0V to 2.4V, the OCV table of FIG. 3 is referenced to detect the SOC according to the voltage, that is, 90% and 5% %. In addition, the operation unit 400 calculates the changed capacity by subtracting the FCC capacity from the initial capacity by the degree of SOC reduction, and calculates a new SOC according to the reduced usage range. Here, the operation unit 400 calculates the changed capacity by using Equation (1), and calculates the changed SOC using Equation (2).

A schematic diagram for calculating the changed capacity X 'and the changed SOC (I') is shown in FIG. As shown in FIG. 5, the maximum voltage and the minimum voltage are denoted by Vfc and Ve, respectively, and the maximum and minimum SOC are 100% and 0%, respectively. Also, the upper and lower capacity reduction rates are denoted by A% and B%, respectively, and the initial and changed SOC are denoted by I and I ', respectively. The changed maximum voltage and minimum voltage are denoted by V'fc and V'e, respectively. The modified capacity X 'can be calculated by multiplying the initial capacity X by a value obtained by subtracting 1 from the sum of the upper capacity reduction ratio A% and the lower capacity reduction ratio B% as shown in the following equation (1) have. The modified SOC (I ') is a value obtained by subtracting the lower capacity reduction ratio (B%) from the initial SOC (I) as the upper capacity reduction ratio (A%) and the lower capacity reduction ratio B%) divided by the value minus 100%. For example, assume that the maximum and minimum voltages are 4.2 V and 2.0 V, respectively, and the initial SOC is 40%, and the high capacity reduction ratio A% and the low capacity reduction ratio B% are 10% and 5% , The changed capacity is calculated as 1275 mAh by Equation (1), and the changed SOC is calculated as 41% by Equation (2). Table 1 shows examples of the modified capacity and SOC calculated by Equations (1) and (2) according to initial capacity and initial SOC and upper and lower capacity subtraction rates.

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7
Initial capacity (mAh)	1500	3000	2800	2200	3000	2400	2400
High Capacity Deduction Rate (%)	10%	15%	7%	0%	2%	10%	10%
Sub-capacity deduction rate (%)	5%	3%	0%	7%	8%	3%	3%
Initial SOC (%)	40%	60%	55%	64%	60%	95%	2%
Modified Capacity (mAh)	1275	2460	2604	2046	2700	2088	2088
Changed SOC (%)	41%	70%	59%	61%	58%	106%	-One%

However, when the changed SOC exceeds the reduced range, it is calculated as over SOC or under SOC. That is, as shown in Example 6, the changed SOC is 11% larger than the initial SOC and exceeds 10%, which is the reduced range. Therefore, the changed SOC is 3% smaller than the initial SOC as shown in Example 7, The calculation unit 400 calculates the SOC according to the usage voltage thus calculated, that is, the OCV according to the usage voltage reduction, and stores the calculated SOC and the OCV in the memory unit 300. That is, the OCV table newly calculated in the existing OCV table is updated and stored. At this time, the new data may be stored in an overwrite form on the existing data or may be stored as data separate from the existing data. In the new OCV table, the maximum voltage 4V set by the user is set to SOC 100%, the minimum voltage 2.4V is set to SOC 0%, and the SOC due to OCV therebetween can be calculated and stored in Equation (1). An example of this new OCV table is shown in FIG. 4, and a graph comparing the initial OCV table with the changed OCV table data is shown in FIG.

As described above, the apparatus for estimating SOC of a battery according to an embodiment of the present invention includes a sensing unit 100, an SOC estimating unit 200, a memory unit 300, and an operation unit 400, The capacity of the battery whose operating voltage range has been changed according to the manufacturer's needs can be estimated using the initial SOC of the OCV table. For example, the use voltage range may be changed according to the manufacturer's request for a battery whose manufacture voltage is set to be the range of the battery, and the present voltage SOC is calculated with reference to the OCV table. Calculate the SOC reduction by referring to the OCV table for the upper and lower voltage use ranges, subtract the FCC capacity by the reduction amount, and recalculate the new SOC for the reduced use range. Therefore, by estimating the changed SOC according to the reduction of the voltage range of the user, it is possible to prevent the occurrence of an error, thereby enabling the stable use of the battery.

Meanwhile, as described above, the capacity of the battery 10 whose operating voltage range is changed is estimated using the SOC estimating apparatus of the present invention, and the battery 10 whose operating voltage range is changed by using the battery management apparatus is charged and discharged . 7 and 8 show a battery management apparatus including the SOC estimating apparatus of the present invention. FIG. 7 is a block diagram of a battery management apparatus according to an embodiment of the present invention, and FIG. 8 is a block diagram of a battery management apparatus for explaining a configuration of a switching unit of the battery management apparatus.

7, a battery management apparatus according to an embodiment of the present invention includes a battery 10 including a plurality of battery cells 11, 12, 13, 14, ..., 1n, A SOC estimating unit 200 for estimating the SOC of the battery, a memory unit 300 for storing data such as SOC and voltage of the battery 10, And a controller (not shown) for controlling the charging and discharging of the battery 10 according to the state of the battery 10 by referring to the re-calculated SOC And a switching unit 600 for controlling connection between the battery 10 and the load according to a control signal of the control unit 500. [ That is, the battery management apparatus of the present invention may include a control unit 500 and a switching unit 600 in the SOC estimating apparatus including the sensing unit 100, the SOC estimating unit 200, and the calculating unit 400 have. Since the SOC estimating device has already been described, the control unit 500 and the switching unit 600 of the battery management apparatus of the present invention will be described in detail as follows.

5. Control section

The control unit 500 generates a control signal according to the voltage of each of the plurality of battery cells measured by the sensing unit 100 to control the switching unit 600 between the battery 10 and the load, . Therefore, overcharge or overdischarge of the battery cell can be prevented. For example, the control unit 500 compares the first set voltage for stopping the charging operation and the second set voltage for performing the charging operation with the voltages of the plurality of battery cells measured by the sensing unit 100 Generates a control signal for stopping the charging operation of the battery cell when the voltage is higher than or equal to the first set voltage, and generates a control signal for charging operation of the battery cell when the measured voltage is lower than or equal to the second set voltage . Here, when the maximum charging voltage of each of the plurality of battery cells is 4.0 V, the first set voltage may be set to, for example, 3.8 V to prevent overcharging, and the second set voltage may be set to, for example, It may be set to 2.4V, for example. Also, the control unit 500 can control the charge / discharge of the battery cell by changing the set voltage of the battery cell according to the changed capacity of the battery cell. For example, when the maximum charge voltage is changed from 4.0 V to 3.8 V and the minimum voltage is changed to 2.5 V, the control unit 500 may use the operation result of the operation unit 400 or the data updated and stored in the memory unit 300 So that the first and second set voltages can be changed and compared with the data of the memory cell. For example, when the first set voltage is changed to 3.8 V and the minimum charge voltage is changed to 2.5 V, the first set voltage is changed to 3.6 V and the minimum charge voltage is changed to 2.6 V, have. Therefore, it is possible to control the charging and discharging of the battery cell according to the change of the maximum charging voltage and the minimum charging voltage of the battery cell, thereby preventing overcharging and overdischarge of the changed battery cell.

6. Switching section

The switching unit 600 is provided between a current path between the battery 10 and the load, and controls the charging and discharging of the battery 10 by the control unit 500. The switching unit 600 may include a first switch 610 and a second switch 620 as shown in FIG. That is, the switching unit 600 is provided between the battery 10 and the load. The first switch 610 may be provided on the battery 10 side and the second switch 620 may be provided on the load side. The first and second switches 610 and 620 are driven according to the control signal generated by the controller 500 and can be driven simultaneously when charging and discharging the battery 10 and either one of them may be driven. For example, the first switch 610 may be driven when the battery 10 is charged, and the second switch 620 may be driven when the battery 10 is discharged. Here, the load may include an external power source for charging the battery 10, and an electronic device to which the battery 10 driven according to the discharge voltage of the battery 10 is mounted. That is, when the battery 10 is charged, the battery 10 is connected to an external power source, and when the battery 10 is discharged, the battery 10 can be connected to the electronic device.

The first switch 610 may include a first FET 610a and a first parasitic diode 610b. The first FET 610a has a source terminal and a drain terminal provided between the battery 10 and the first node Q1 and a gate terminal connected to the control unit 500. [ Accordingly, the first FET 610a is driven in accordance with a control signal output from the controller 500, and functions to apply a current to the battery 10 during charging. The first parasitic diode 610b is connected in parallel to the first FET 610a. That is, the first parasitic diode 610b is connected in a forward direction between the battery 10 and the first node Q1. This first parasitic diode 610b sets the discharge path of the battery 10 when the first FET 610a is turned off. That is, the battery 10 is charged through the first FET 610a, and the battery 10 can be discharged through the first parasitic diode 610b.

The second switch 620 may include a second FET 620a and a second parasitic diode 620b. A source terminal and a drain terminal of the second FET 620a are provided between the first node Q1 and the load, and a gate terminal is connected to the control unit 500. [ Accordingly, the second FET 620a is driven in accordance with a control signal output from the controller 500, and serves to apply the discharge current of the battery 10 to the electronic device connected to the second FET 620a. The second parasitic diode 620b is connected in parallel to the second FET 620a. That is, the second parasitic diode 620b is connected in the reverse direction between the first node Q1 and the load. The second parasitic diode 620b sets the path of the charging current when the battery 10 is charged. That is, the battery 10 is discharged through the second FET 620a, and the battery 10 can be charged through the second parasitic diode 620b.

The switching unit 600 is connected to the gate terminal of the first FET 610a and the gate terminal of the second FET 620a and the control unit 500 is connected to the first and second FETs 620a and 620b in response to a control signal output from the control unit 500. [ FETs 610a and 620a are driven, respectively. The control unit 500 turns on the first FET 610a and turns off the second FET 620b when the battery 10 is charged. Therefore, the battery 10 is charged from the load, i.e., the external power supply, through the second parasitic diode 620b and the first FET 610a. In addition, the controller 500 turns on the second FET 620a and turns on the second FET 610a when the battery 10 is discharged. Thus, the battery 10 is discharged from the battery 10 through the first FET 610a and the second parasitic diode 620b. At this time, the control signal for turning on the first and second FETs 610a and 620a, respectively, may be a logic high signal, and the control signal for turning off the first and second FETs 610a and 620a, respectively, may be a logic low signal .

As described above, the battery control apparatus according to an embodiment of the present invention can control the charging / discharging of the battery 10 after sensing the state of the battery 10. [ Also, the battery control device can control the charging / discharging of the battery 10 according to the capacity of the battery 10 changed after the capacity and SOC of the battery 10 are changed by the SOC estimating device. When the capacity of the battery 10 is reduced, the charge / discharge of the battery can be controlled by lowering the set voltage according to the reduced capacity.

FIG. 9 is a flowchart illustrating an SOC estimation method according to an embodiment of the present invention, and FIG. 10 is a detailed flowchart of a process.

9 and 10, an SOC estimation method according to an embodiment of the present invention includes a step S100 of measuring the OCV and current of the battery 10, (S200) of matching an OCV with an initial SOC and extracting an initial SOC according to the OCV, calculating a reduction degree of the SOC according to the range of the voltage to be used and restoring the SOC according to the reduced use range (S300) And calculating and storing the calculated SOC and the corresponding OCV (S400). (S310) of calculating the degree of SOC reduction using the upper and lower ranges of the operating voltage range according to the operating voltage range change (S310) (S320) of calculating the changed capacity by subtracting the new capacity (S320), and calculating a new SOC according to the reduced usage range (S330). The SOC estimation method according to an embodiment of the present invention will be described in detail as follows.

S100: The voltage of the battery 10 is measured using the sensing unit 100. That is, the voltage is stabilized after a predetermined time from the battery pack after the BMS is enabled by using the voltage sensor, that is, the OCV is measured. Also, the sensing unit 100 may measure the current of the battery pack using a current sensor.

S200: The SOC estimating unit 200 matches the measurement OCV with the initial OCV stored in the memory unit 300 and estimates the initial SOC according to the initial OCV. Various data for operating the battery 10 may be stored in the memory unit 300. In particular, various experimentally measured initial SOCs and corresponding initial OCVs may be matched and stored. For example, the SOC from 0% to 100% and the OCV according to each SOC can be measured and stored as matching as shown in FIG. Therefore, the OCV measured from the sensing unit 100 can be compared with the initial OCV stored in the memory unit 300, and the initial SOC can be extracted accordingly.

S300: The calculation unit 400 calculates the degree of SOC reduction according to the range of the use voltage and recalculates the SOC according to the reduced usage range. The SOC re-calculation process according to the change in the operating voltage range is as shown in FIG. 7 as follows.

S310: The calculation unit 400 calculates the degree of SOC reduction using the upper and lower ranges of the voltage range for use according to the range of the voltage to be used. That is, the operation unit 400 calculates the degree of SOC reduction by referring to the initial OCV table of the memory unit 300, the upper and lower ranges of the operating voltage range. For example, when the operating voltage range is from 4.0V to 2.4V, the OCV table of FIG. 3 is referenced to detect the SOC according to the voltage, that is, 90% and 5% %.

S320 and S330: The operation unit 400 calculates the changed capacity by subtracting the FCC capacity from the initial capacity by the degree of SOC reduction, and calculates a new SOC according to the reduced usage range. Here, the operation unit 400 calculates the changed capacity by using Equation (1), and calculates the changed SOC using Equation (2). That is, as shown in [Equation 1], the changed capacity X 'is obtained by multiplying the initial capacity X by a value obtained by subtracting 1 from the sum of the upper capacity reduction ratio A% and the lower capacity reduction ratio B% Can be calculated. The modified SOC (I ') is a value obtained by subtracting the lower capacity reduction ratio (B%) from the initial SOC (I) as the upper capacity reduction ratio (A%) and the lower capacity reduction ratio B%) divided by the value minus 100%. For example, assume that the maximum and minimum voltages are 4.2 V and 2.0 V, respectively, and the initial SOC is 40%, and the high capacity reduction ratio A% and the low capacity reduction ratio B% are 10% and 5% , The changed capacity is calculated as 1275 mAh by Equation (1), and the changed SOC is calculated as 41% by Equation (2).

S400: The operation unit 400 calculates the SOC and the OCV according to the calculated use voltage reduction, and stores the calculated SOC and the OCV in the memory unit 300. FIG. That is, the OCV table newly calculated in the existing OCV table is updated and stored. At this time, the new data may be stored in an overwrite form on the existing data or may be stored as data separate from the existing data. In the new OCV table, the maximum voltage 4V set by the user is set to SOC 100%, the minimum voltage 2.4V is set to SOC 0%, and the SOC due to OCV therebetween can be calculated and stored in Equation (1). An example of this new OCV table is shown in FIG.

Meanwhile, as described above, the capacity of the battery 10 whose use voltage range is changed is estimated by using the SOC estimating device of the present invention. By using the battery management apparatus shown in FIGS. 7 and 8, (10) can be charged and discharged. That is, the control unit 500 can control the charge / discharge of the battery cell by changing the set voltage of the battery cell according to the changed capacity of the battery cell. For example, when the maximum charge voltage is changed from 4.0 V to 3.8 V and the minimum voltage is changed to 2.5 V, the control unit 500 may use the operation result of the operation unit 400 or the data updated and stored in the memory unit 300 The first and second set voltages are changed to be compared with the data of the memory cell, and then the charging and discharging of the battery cell can be controlled. That is, the charging and discharging of the battery cell can be controlled in accordance with the change of the maximum charging voltage and the minimum charging voltage of the battery cell, thereby preventing overcharge and overdischarge of the changed battery cell.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

Claims (16)

1. battery;

   A sensing unit connected to the battery to measure OCV of the battery;

   An SOC estimator connected to the sensing unit and estimating the SOC of the battery using the OCV measured from the sensing unit;

   A memory unit for storing data including SOC and OCV of the battery and connected to the SOC estimating unit; And

   And an arithmetic unit connected to the SOC estimating unit and the memory unit, for calculating a degree of SOC reduction according to the range of the voltage to be used, and for outputting the changed SOC according to the changed used capacity.
2. The apparatus of claim 1, wherein the memory unit stores a plurality of initial SOCs and a plurality of initial OCVs by matching and storing a plurality of changed SOCs and a plurality of changed OCVs.
3. The battery capacity estimating apparatus according to claim 1, wherein the calculating unit calculates the capacity changed by the following equation (1).

   [Equation 1]

   

   Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.
4. 4. The battery capacity estimating apparatus according to claim 3, wherein the calculating unit calculates the changed SOC using Equation (2).

   &Quot; (2) "

   

   Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.
5. battery;

   A sensing unit connected to the battery to measure OCV of the battery;

   An SOC estimator connected to the sensing unit and estimating the SOC of the battery using the OCV measured from the sensing unit;

   A memory unit for storing data including SOC and OCV of the battery and connected to the SOC estimating unit;

   A calculating unit connected to the SOC estimating unit and the memory unit, for calculating a degree of SOC reduction according to a change in the operating voltage range and for outputting a changed SOC according to the changed used capacity;

   A control unit connected to at least one of the operation unit and the memory unit to control charging and discharging of the battery according to the state of the battery by referring to the SOC; And

   And a switching unit provided between the battery and the load for charging / discharging the battery according to a control signal of the control unit.
6. The battery capacity estimating apparatus according to claim 5, wherein the calculating unit calculates the capacity changed by the following equation (1) and calculates the changed SOC using the following equation (2).

   [Equation 1]

   

   Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.

   &Quot; (2) "

   

   Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.
7. The process of measuring the OCV of the battery;

   Estimating an initial SOC according to the measured OCV;

   Calculating the SOC reduction degree according to the use voltage range change and calculating the changed SOC; And

   And calculating a changed OCV according to the changed SOC.
8. 8. The method of claim 7, further comprising the step of matching and storing a plurality of initial SOCs of the battery and a plurality of initial OCVs corresponding thereto.
9. 9. The method of claim 8, wherein the initial SOC is estimated by matching the measured OCV with the initial OCV.
10. The method as claimed in claim 7, wherein the step of calculating the changed SOC comprises:

    Calculating a changed capacity by subtracting from the initial capacity by the degree of SOC change;

    And calculating the changed SOC.
11. 11. The method of claim 10, wherein the modified capacity is calculated by: < EMI ID = 1.0 >

    [Equation 1]

    

    Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.
12. 11. The method of claim 10, wherein the modified SOC is calculated using Equation (2).

    &Quot; (2) "

    

    Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.
13. 8. The method of claim 7, further comprising storing a plurality of data by matching the changed SOC and the changed OCV.
14. The process of measuring the OCV of the battery;

    Estimating an initial SOC according to the measured OCV;

    Calculating the SOC reduction degree according to the use voltage range change and calculating the changed SOC;

    Calculating a changed OCV according to the changed SOC; And

    And controlling charging and discharging of the battery according to the state of the battery with reference to the changed SOC.
15. The method of claim 14, wherein calculating the modified SOC comprises: calculating a degree of SOC change according to a change in the operating voltage range;

    Calculating a changed capacity by subtracting from the initial capacity by the degree of SOC change;

    And calculating the changed SOC.
16. 16. The method of claim 15, wherein the modified capacity is calculated using Equation (1) and the modified SOC is calculated using Equation (2).

    [Equation 1]

    

    Where X 'is the changed capacity, X is the initial capacity, A and B are the high and low capacity subtraction rates.

    &Quot; (2) "

    

    Where I 'is the changed SOC, I is the initial SOC, A and B are the high and low capacity subtraction rates.

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