KR102225896B1 - Low-voltage power supply apparatus and method utilizing battery cell - Google Patents

Abstract

The present invention relates to an apparatus and method for supplying a low voltage power supply using a battery cell, and more particularly, a voltage converter is connected to a first battery cell among a plurality of battery cells included in a battery to preset an output voltage of the first battery cell. Low-voltage power supply device and method using a battery cell that converts to a set low voltage and controls balancing of the second battery cell so that the discharged electricity amount of the second battery cell not connected to the voltage converter is the same as the output electricity amount of the first battery cell It is about.

Description

Low-voltage power supply apparatus and method using a battery cell TECHNICAL FIELD

The present invention relates to a low voltage power supply device and method using a battery cell, and more particularly, to provide a low voltage power by converting an output voltage of a first battery cell among a plurality of battery cells included in the battery into a preset low voltage. It relates to a low voltage power supply device and method using a battery cell.

Recently, due to the depletion of fossil energy and environmental pollution due to the use of fossil energy, interest in electric products that can be driven using secondary battery batteries is increasing. Accordingly, technology development for mobile devices, electric vehicles (EV), hybrid vehicles (HV), energy storage systems (ESS), and uninterruptible power supplies (UPS), etc. As the demand and demand increase, the demand for rechargeable batteries as an energy source is rapidly increasing.

These secondary battery batteries are attracting attention as a new energy source for eco-friendliness and energy efficiency improvement in that they do not generate by-products from the use of energy as well as the primary advantage of being able to drastically reduce the use of fossil energy.

In particular, in response to the demand for eco-friendly products and the demand for improvement in fuel economy, research on a hybrid electric vehicle using a secondary battery battery is being conducted more actively.

Hybrid vehicle refers to driving a vehicle by efficiently combining two or more different types of power sources, and in most cases, driving power is obtained by an engine that uses fuel to obtain driving power and an electric motor that is driven by the power of a secondary battery battery. Refers to the vehicle.

Recently, the capacity of the secondary battery battery is made larger than that of conventional hybrid vehicles, and the secondary battery battery is charged from an external power source. A plug-in hybrid vehicle (PHEV) is being developed that operates in HEV (Hybrid Electric Vehicle) mode, which is an auxiliary mode that uses the rotational power of the motor as the auxiliary power while using the rotational power of the motor as the main power.

These plug-in hybrid vehicles or hybrid vehicles are configured to separate and separate the high-voltage part receiving high-voltage power from the high-voltage part and the low-voltage part receiving low voltage from a low-voltage battery such as a lead acid battery to drive a motor that receives a high voltage from a secondary battery battery. Prevents malfunction of CAN communication line and control unit due to noise.

In this case, when a high voltage secondary battery is used to supply power to a low voltage unit, a linear regulator converting a high voltage to a low voltage is used.

Such a linear regulator serves to convert a high voltage DC voltage from a secondary battery battery into a low voltage DC voltage and provide it to the electric load of the vehicle.

More specifically, the linear regulator cuts down the high voltage of the secondary battery battery and supplies about 5V to the lead acid battery for charging or supplying power to the electric load.

The input voltage of the linear regulator is the output voltage of secondary battery batteries installed in electric vehicles and hybrid vehicles, and the input voltage ranges from about 60V to 450V very different depending on the type of vehicle.

As described above, a linear regulator that converts an output voltage output from all battery cells included in a secondary battery into a low residual voltage has a problem in that the price increases as the input voltage range increases.

In addition, the linear regulator has a problem of accelerating deterioration of peripheral components by generating heat in the process of converting a high voltage from a minimum of about 60V to a maximum of 450V to a low voltage of about 5V.

Korean Patent Publication No. 10-2014-0106982

An object of the present invention is a second battery that is connected to a first battery cell among a plurality of battery cells included in the battery, a voltage converter converts the output voltage of the first battery cell into a preset low voltage, and is not connected to the voltage converter By controlling the balancing of the second battery cell so that the discharged electricity amount of the cell is the same as the output electricity amount of the first battery cell, a low-voltage power source can be provided by using a voltage converter with low heat generation and component cost. It is to provide a low voltage power supply apparatus and method using battery cells capable of equally controlling the amount of electricity consumed between battery cells.

A low voltage power supply device using a battery cell according to the present invention includes: a voltage converter connected to a first battery cell among a plurality of battery cells included in a battery to convert the output voltage of the first battery cell into a preset low voltage; A calculator configured to calculate an amount of output electricity output from the first battery cell to the voltage converter; And controlling a connection between the second battery cell and a balancing resistor for discharging the second battery cell such that an amount of discharged electricity of a second battery cell not connected to the voltage converter among the plurality of battery cells is the same as the amount of output electricity. It is configured to include;

In an embodiment, a measurement unit that measures an output current value of an output current output from the first battery cell to the voltage converter may be further included.

In an embodiment, the calculation unit may calculate the output electricity quantity using an output current value of the measured output current and an output time at which the output current is output.

In an embodiment, the calculation unit may calculate the output electricity amount by using the following equation.

<Equation>

Here, Qo is the output electricity quantity, Io is the output current value, and to is the output time.

In an embodiment, the estimating unit may further include an estimating unit for estimating a discharge current value of a discharge current flowing through the balancing resistor by using at least one of a charging voltage of the second battery cell and a balancing resistance value of the balancing resistance. have.

In one embodiment, the controller calculates a balancing time at which the second battery cell and the balancing resistor are connected using the discharge current value so that the discharge electricity amount and the output electricity amount are the same, and during the calculated balancing time, the The second battery cell may be discharged by connecting the second battery cell and the balancing resistor.

In an embodiment, the controller may calculate the balancing time using the following equation.

<Equation>

Here, tb is the balancing time, Qb is the discharge electricity amount, Ib is the discharge current value, Qo is the output electricity amount, and Io is the output current value.

The method of supplying low voltage power using a battery cell according to the present invention includes the steps of: a voltage converter connected to a first battery cell among a plurality of battery cells included in a battery to convert the output voltage of the first battery cell into a preset low voltage; Calculating, by a calculation unit, an amount of output electricity output from the first battery cell to the voltage converter; And a balancing resistor for discharging the second battery cell and the second battery cell so that the amount of discharged electricity of a second battery cell not connected to the voltage converter among the plurality of battery cells is equal to the output amount of electricity. It is configured to include; step of controlling.

In one embodiment, the method of supplying low voltage power using the battery cell may further include measuring an output current value of an output current output from the first battery cell to the voltage converter by a measurement unit.,

In an embodiment, the calculating may include calculating, by the calculation unit, the output electricity quantity using an output current value of the measured output current and an output time at which the output current is output.,

In an embodiment, the calculating may further include calculating the output electricity quantity by using the following equation by the calculation unit.,

<Equation>

Here, Qo is the output electricity quantity, Io is the output current value, and to is the output time.

In one embodiment, in the method of supplying low voltage power using the battery cell, the measurement unit calculates the discharge current value of the discharge current flowing through the balancing resistor by using at least one of the charging voltage of the second battery cell and the balancing resistance value of the balancing resistor. Estimating; may further include.,

In one embodiment, in the controlling step, the control unit calculates a balancing time at which the second battery cell and the balancing resistor are connected using the discharge current value so that the discharge electric quantity and the output electric quantity are the same, and the calculation It may include a step of discharging the second battery cell by connecting the second battery cell and the balancing resistor during the defined balancing time.,

In an embodiment, the controlling may further include calculating, by the controller, the balancing time using the following equation.,

<Equation>

Here, tb is the balancing time, Qb is the discharge electricity amount, Ib is the discharge current value, Qo is the output electricity amount, and Io is the output current value.

In the low voltage power supply apparatus and method using a battery cell according to the present invention, the voltage converter is connected to a first battery cell among a plurality of battery cells included in the battery to convert the output voltage of the first battery cell into a preset low voltage, and the voltage By controlling the balancing of the second battery cell so that the discharged electricity amount of the second battery cell not connected to the conversion unit is the same as the output electricity amount of the first battery cell, a low-voltage power supply can be provided using a voltage conversion unit with low heat generation and component cost It has the effect of controlling the amount of electricity consumed between the first battery cell and the second battery cell in the same manner.

1 is a diagram schematically illustrating an electric vehicle to which a low voltage power supply device using a battery cell according to an embodiment of the present invention can be applied.
2 is a block diagram showing the configuration of a low voltage power supply device using a battery cell according to an embodiment of the present invention.
3 is a diagram illustrating an example of a specific configuration of a low voltage power supply device using a battery cell according to an embodiment of the present invention.
4 is a flowchart illustrating a method of supplying low voltage power using a battery cell according to an embodiment of the present invention.

The present invention will be described in detail with reference to the accompanying drawings as follows. Here, repeated descriptions, well-known functions that may unnecessarily obscure the subject matter of the present invention, and detailed descriptions of configurations are omitted. Embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

In addition, the term "... unit" described in the specification means a unit that processes one or more functions or operations, which may be implemented by hardware or software, or a combination of hardware and software.

1 is a diagram schematically illustrating an electric vehicle to which a low voltage power supply device using a battery cell according to an embodiment of the present invention can be applied.

1 shows an example in which a low-voltage power supply device using a battery cell according to an embodiment of the present invention is applied to an electric vehicle, but the low-voltage power supply device using a battery cell according to an embodiment of the present invention is used in addition to the electric vehicle. Any field of technology can be applied as long as a secondary battery battery can be applied, such as a mobile device, an energy storage system, or an uninterruptible power supply.

The electric vehicle 1 may include a battery 10, a battery management system (BMS) 20, an electronic control unit (ECU) 30, an inverter 40, and a motor 50.

The battery 10 is an electric energy source for driving the electric vehicle 1 by providing a driving force to the motor 50. The battery 10 may be charged or discharged by the inverter 40 according to the driving of the motor 50 or an internal combustion engine (not shown).

Here, the type of the battery 10 is not particularly limited, and may include, for example, 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, the state of the battery 10 state information such as state of charging (SOC), remaining life (State Of Health; SOH), maximum input/output power allowance, and output voltage is estimated and managed. In addition, charging or discharging of the battery 10 is controlled using this state information, and further, it is possible to estimate the replacement timing of the battery 10.

In addition, the BMS 20 may include a low voltage power supply device (100 in FIG. 2) using a battery cell to be described later. The low voltage power supply device 100 using such a battery cell is connected to a first battery cell among a plurality of battery cells included in the battery 10 to convert the output voltage of the first battery cell into a preset low voltage, and a voltage converter Low voltage power can be provided from the battery 10 by controlling the balancing of the second battery cell so that the amount of discharged electricity of the second battery cell not connected to is equal to the amount of output of the first battery cell.

A detailed description of how the low voltage power supply device 100 using a battery cell provides low voltage power and performs balancing between the first battery cell and the second battery cell will be described in detail with reference to FIG. 2.

The ECU 30 is an electronic control device that controls the state of the electric vehicle 1. For example, a torque degree is determined based on information such as an accelerator, a brake, and a speed, and the output of the motor 50 is controlled to match the torque information.

In addition, the ECU 30 transmits a control signal to the inverter 40 so that the battery 10 can be charged or discharged based on status information such as SOC and SOH of the battery 10 received by the BMS 20. .

The inverter 40 allows the battery 10 to be charged or discharged based on a control signal from the ECU 30.

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

FIG. 2 is a block diagram showing the configuration of a low voltage power supply device using a battery cell according to an embodiment of the present invention, and FIG. 3 is a specific configuration of a low voltage power supply device using a battery cell according to an embodiment of the present invention. It is a diagram showing an example of.

2 and 3, the low voltage power supply device 100 using a battery cell includes a balancing unit 110, a voltage converting unit 120, a measuring unit 130, a calculating unit 140, and an estimating unit 150. ) And the control unit 160 may be included. The low-voltage power supply device 100 using the battery cells shown in FIGS. 2 and 3 is according to an embodiment, and its components are not limited to the embodiments shown in FIGS. 2 and 3, as necessary. It can be added, changed or deleted.

The low-voltage power supply device 100 using a battery cell includes a battery 10 including battery cells 11a and 11b and battery cells 11a and 11b based on voltage, current, and temperature, respectively. The remaining capacity (State Of Charging; SOC), the remaining life (State Of Health; SOH) and the maximum input/output power allowance are calculated, and the calculated state information (SOC, SOH and maximum input/output power allowance) of the battery cells 11a and 11b are calculated. ) May be included in a battery management system (BMS, 20) that controls charging or discharging of the battery cells 11a and 11b.

Meanwhile, the battery cells 11a and 11b may include a first battery cell 11a and a second battery cell 11b.

More specifically, the first battery cell 11a may be connected to a voltage converter 120 to be described later to output an output voltage to the voltage converter 120, and the second battery cell 11b is a battery cell 11a. Among, 11b), it may be a battery cell that is not connected to the voltage converter 120.

In this case, the battery cells 11a and 11b, that is, the first battery cell 11a and the second battery cell 11b, may be respectively connected to the balancing unit 110 to be charged or discharged.

Meanwhile, in FIG. 2, the low voltage power supply device 100 using a battery cell according to an embodiment of the present invention includes a battery 10 having two first and second battery cells 11a and 11b. Although shown to be connected to, the first battery cell 11a and the first battery cell 11a may be set in response to the maximum charging voltage of one, and the number of each of the second battery cells 11b is not limited. Please note.

The balancing unit 110 may serve to discharge the charging voltages of the first and second battery cells 11a and 11b. To this end, the balancing unit 110 may include a switching element 111 and a balancing resistor 112.

Here, the switching device 111 may be any one of a metal oxide silicon field effect transistor (MOS FET) device, an insulated gate bipolar transistor (IGBT) device, and a bipolar junction transistor (BJT) device.

When the switching device 111 is a MOS FET device, the balancing unit 110 may further include a gate resistor 113 for adjusting a gate voltage of the MOS FET device in addition to the balancing resistor 112.

Hereinafter, the balancing unit 110 in which the switching element 111 is a MOS FET element will be described.

The switching element 111 may include a drain terminal (D), a gate terminal (G), and a source terminal (S), and the drain terminal (D) and the gate terminal (G) have a balancing resistor 112 and a gate resistance, respectively. It can be connected to (113).

When a gate voltage higher than the threshold voltage is applied to the gate terminal (G), the switching element 111 is a balancing resistor connected to the drain terminal (D) by energizing the drain terminal (D) and the source terminal (S). 112) may flow.

That is, the switching element 111 is energized so that the current output from the first battery cell 11a and the second battery cell 11b flows through the balancing resistor 112, so that the first battery cell 11a and the second battery cell (11b) is discharged, and thus, a voltage value of the charging voltage charged in the first battery cell 11a and the second battery cell 11b may be reduced.

Meanwhile, the resistance value of the gate resistor 113 may be changed in order to adjust the gate voltage applied to the gate terminal G in response to the threshold voltage of the switching element 111.

The power converter 120 may be connected to the first battery cell 11a to convert an output voltage output from the first battery cell 11a into a preset low voltage.

Here, the preset low voltage may be set as a voltage of a low voltage power source for driving the electric vehicle 1.

The power converter 120 may be a linear regulator or a low drop out (LDO) regulator that converts a high voltage DC voltage into a low voltage DC voltage.

Through this, the power conversion unit 120 is connected to only some of the first battery cells 11a among the battery cells 11a and 11b, so that the output voltage of the first battery cell 11a is lower than the output voltage of the entire battery 10 By converting the high voltage to a low voltage, heat generated in the process of converting a high voltage of at least 60V or higher to a low voltage can be prevented.

Meanwhile, the low voltage power converted from the power conversion unit 120 may be provided as power for driving the electric vehicle 1.

As described above, when low voltage power is provided by connecting only the power converter 120 and the first battery cell 11a, only the amount of electricity charged in the first battery cell 11a is consumed, so that the first battery cell 11a An imbalance in the amount of charged electricity occurs between the and the second battery cell 11b.

Accordingly, the low-voltage power supply device 100 using a battery cell according to an exemplary embodiment of the present invention provides a second battery so that the discharged electricity amount of the second battery cell 11b is the same as the output electricity amount of the first battery cell 11a. It is possible to control the balancing of the cell 11b.

To this end, the measurement unit 130 may serve to measure an output current value of an output current output from the first battery cell 11a to the voltage converter 120.

At this time, the measurement unit 130 is a voltage for measuring a voltage applied as an output current flows through the measurement resistor 131 and the measurement resistor 131 connected between the voltage converter 120 and the first battery cell 11a. It may include a measurement sensor 132.

Although it has been described that the measurement unit 130 according to an embodiment measures the output current value using the measurement resistance 131 and the voltage measurement sensor 132, the configuration of the measurement unit 130 as long as the output current value is measured. Note that the type of family is not limited.

For example, the measurement unit according to another embodiment may include a Hall sensor that measures current using a magnetic field.

The calculation unit 140 may perform a role of calculating the amount of output electricity output from the first battery cell 11a to the voltage converter 120 by using the output current value measured by the measurement unit 130.

More specifically, the calculation unit 140 may calculate an output electricity amount using the measured output current value and an output time at which the output current is output from the first battery cell 11a to the voltage converter 120.

In this case, the calculation unit 140 may calculate the amount of output electricity by using Equation 1 below.

<Equation 1>

Here, Qo is the output electricity quantity, Io is the output current value, and to is the output time.

Here, the amount of output electricity may be an amount of output electricity output from each battery cell of the first battery cell 11a to the power converter, that is, the amount of electricity consumed.

As described above, when low voltage power is provided by connecting only the power converter 120 and the first battery cell 11a, only the amount of electricity of the first battery cell 11a is consumed, and thus the first battery cell 11a and the first battery cell 11a are used. 2 An imbalance in the amount of charged electricity occurs between the battery cells 11b.

At this time, when the second battery cell 11b is not charged and discharged, an imbalance in the amount of electricity occurs between the first battery cell 11a and the second battery cell 11b as much as the output electricity amount calculated from the calculation unit 140. do.

Hereinafter, a method of preventing an imbalance in the amount of electricity between the first battery cell 11a and the second battery cell 11b will be described.

The estimating unit 150 may perform a role of estimating a discharge current value of a discharge current flowing from the second battery cell 11b to the balancing resistor 112.

More specifically, the estimating unit 150 uses the balancing resistance value of the balancing resistance 112 included in the balancing unit 110 and the current charging voltage of the second battery cell 11b to flow through the balancing resistance 112. The discharge current value of the discharge current can be estimated.

Through this, the estimating unit 150 may estimate the discharge current value of the second battery cell 11b without separately connecting or providing a separate sensor or a measurement resistor, like the measurement unit 130.

Here, the balancing resistance value of the balancing resistor 112 may be stored in advance for each balancing unit 110, and the charging voltage of the second battery cell 11b may be received from the above-described BMS.

Meanwhile, the estimating unit 150 according to an embodiment has been described as estimating using the characteristic values of the elements included in the balancing unit 110 without measuring the discharge current value of the second battery cell 11b. The low voltage power supply device 100 using the battery cell according to the example may measure the discharge current value through the same discharge current value measuring unit as the above-described measuring unit 130 in place of the estimating unit 150.

The control unit 160 connects the second battery cells 11a and 11b and the balancing resistor 112 by controlling the operating state of the switch element 111 connected to the second battery cell 11b to On during the balancing time. As a result, the second battery cell 11b may be discharged.

In other words, the control unit 160 controls the switch element 111 to consume the amount of electricity of the second battery cell 11b as much as the amount of electricity output from the first battery cell 11a to the power conversion unit 120 to control the balancing time. During the period, the second battery cell 11b may be discharged.

Here, the balancing time is connected to the second battery cell 11b so that when the second battery cell 11b is discharged with the discharge current of the discharge current value estimated from the estimating unit 150, the amount of discharged electricity is equal to the amount of output electricity. It may be a time for controlling the operating state of the switch element 111 to be ON.

That is, when the control unit 160 discharges the second battery cell 11b by controlling the operation state of the switch element 111 connected to the second battery cell 11b to On during the balancing time, the amount of discharged electricity and As the output electricity amount becomes the same, the amount of electricity between the first battery cell 11a and the second battery cell 11b may be uniform.

In this case, the controller 160 may calculate the balancing time using Equation 2 below.

<Equation 2>

Here, tb is the balancing time, Qb is the discharge electricity amount, Ib is the discharge current value, Qo is the output electricity amount, and Io is the output current value.

Accordingly, the low-voltage power supply device 100 using a battery cell according to an embodiment of the present invention not only provides low-voltage power using the voltage converter 120, which has low heat generation and a low component price, but also provides a first battery cell ( The amount of electricity consumed between 11a) and the second battery cell 11b may be equally controlled.

4 is a flowchart illustrating a method of supplying low voltage power using a battery cell according to an embodiment of the present invention.

Referring to FIG. 4, the voltage converter is connected to a first battery cell among a plurality of battery cells included in the battery to convert the output voltage of the first battery cell into a preset low voltage (S401). Here, the preset low voltage may be set as a voltage of a low voltage power source for driving the electric vehicle of the electric vehicle.

Meanwhile, when low voltage power is provided by connecting only the power converter and the first battery cell, only the amount of electricity charged in the first battery cell is consumed, resulting in an imbalance in the amount of electricity charged between the first battery cell and the second battery cell. .

Accordingly, the balancing of the second battery cell 11b is controlled so that the amount of discharged electricity of the second battery cell 11b is the same as the amount of outputted electricity of the first battery cell 11a through steps S402 to S406 to be described later.

More specifically, the measurement unit measures the output current value of the output current output from the first battery cell to the voltage converter (S402), and the calculation unit uses the output current value of the measured output current and the output time at which the output current is output. Thus, the output electricity quantity is calculated (S403).

Next, the estimating unit estimates the discharge current value of the discharge current flowing through the balancing resistor by using at least one of the charging voltage of the second battery cell and the balancing resistance value of the balancing resistor (S404).

The control unit calculates the balancing time that the second battery cell and the balancing resistor are connected using the discharge current value so that the discharged electricity amount and the output electricity amount are the same (S405), and connects the second battery cell and the balancing resistor during the calculated balancing time. So that the second battery cell is discharged (S406).

Accordingly, the method of supplying low voltage power using a battery cell according to an embodiment of the present invention not only provides low voltage power by using a voltage converter with low heat generation and component cost, but also is consumed between the first battery cell and the second battery cell. The amount of electricity can be controlled equally.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. You will understand that you can do it.

100: low voltage power supply using a battery cell
110: balancing unit
111: switching element 112: balancing resistor
113: gate resistance
D: drain terminal G: gate terminal
S: source terminal
120: voltage conversion unit 130: measurement unit
140: calculation unit 150: estimation unit
160: control unit
10: battery
11a: first battery cell 11b: second battery cell
20: battery management system

Claims (14)

A voltage converter connected to a first battery cell among a plurality of battery cells included in a battery to convert an output voltage of the first battery cell into a preset low voltage;
A calculator configured to calculate an amount of output electricity output from the first battery cell to the voltage converter; And
A control unit for controlling a connection between the second battery cell and a balancing resistor for discharging the second battery cell such that an amount of discharged electricity of a second battery cell not connected to the voltage converter among the plurality of battery cells is equal to the output amount of electricity Characterized in that it comprises;
Low voltage power supply using battery cells.
The method of claim 1,
A measuring unit for measuring an output current value of an output current output from the first battery cell to the voltage conversion unit; characterized in that it further comprises,
Low voltage power supply using battery cells.
The method of claim 2,
The calculation unit,
Characterized in that the output electricity quantity is calculated using an output current value of the measured output current and an output time at which the output current is output,
Low voltage power supply using battery cells.
The method of claim 3,
The calculation unit,
Characterized in that the output electricity quantity is calculated using the following equation,
Low voltage power supply using battery cells.

<Equation>

Here, Qo is the output electricity quantity, Io is the output current value, and to is the output time.
The method of claim 2,
An estimating unit for estimating a discharge current value of a discharge current flowing through the balancing resistor by using at least one of a charging voltage of the second battery cell and a balancing resistance value of the balancing resistor; characterized in that it further comprises,
Low voltage power supply using battery cells.
The method of claim 5,
The control unit,
The second battery cell and the balancing resistor are calculated so that the amount of discharged electricity and the amount of output electricity are equal to each other using the discharge current value, and the second battery cell and the balancing resistance are calculated during the calculated balancing time. It characterized in that by connecting to discharge the second battery cell,
Low voltage power supply using battery cells.
The method of claim 6,
The control unit,
Characterized in that calculating the balancing time using the following equation,
Low voltage power supply using battery cells.

<Equation>

Here, tb is the balancing time, Qb is the discharge electricity amount, Ib is the discharge current value, Qo is the output electricity amount, and Io is the output current value.
Converting an output voltage of the first battery cell into a preset low voltage by connecting a voltage converter to a first battery cell among a plurality of battery cells included in the battery;
Calculating, by a calculation unit, an amount of output electricity output from the first battery cell to the voltage converter; And
The control unit controls the connection between the second battery cell and the balancing resistor for discharging the second battery cell so that the amount of discharged electricity of the second battery cell not connected to the voltage converter among the plurality of battery cells is the same as the output amount of electricity. Characterized in that it comprises;
Low voltage power supply method using battery cells.
The method of claim 8,
The step of measuring an output current value of an output current output from the first battery cell to the voltage converter by a measuring unit; characterized in that it further comprises,
Low voltage power supply method using battery cells.
The method of claim 9,
The calculating step,
And calculating the output electricity quantity using the output current value of the measured output current and the output time at which the output current is output;
Low voltage power supply method using battery cells.
The method of claim 10,
The calculating step,
The calculation unit further comprising: calculating the output electricity quantity using the following equation,
Low voltage power supply method using battery cells.

<Equation>

Here, Qo is the output electricity quantity, Io is the output current value, and to is the output time.
The method of claim 9,
Estimating a discharge current value of a discharge current flowing through the balancing resistor by using at least one of a charging voltage of the second battery cell and a balancing resistance value of the balancing resistor by a measuring unit;
Low voltage power supply method using battery cells.
The method of claim 12,
The controlling step,
The control unit calculates a balancing time at which the second battery cell and the balancing resistor are connected using the discharge current value to be the same as the discharge electric quantity and the output electric quantity, and the second battery cell and the second battery cell during the calculated balancing time And discharging the second battery cell by connecting the balancing resistor.
Low voltage power supply method using battery cells.
The method of claim 13,
The controlling step,
Comprising, by the control unit, the balancing time using the following equation; characterized in that it further comprises,
Low voltage power supply method using battery cells.

<Equation>

Here, tb is the balancing time, Qb is the discharge electricity amount, Ib is the discharge current value, Qo is the output electricity amount, and Io is the output current value.

Images