KR20190071455A - Apparatus and method for cell balancing - Google Patents

Abstract

Disclosed by the present invention are a cell balancing device and a method thereof which equalize the charge of at least one secondary battery by using a thermoelectric device. According to an embodiment of the present invention, the cell balancing device, which is a device of equalizing the charge of at least one secondary battery in a battery module having a plurality of secondary batteries, includes: a first balancing circuit which receives power from the secondary battery by being connected with each of both ends of the secondary battery, and is formed to convert the supplied power into thermal energy and emit the energy; a thermoelectric module which has at least one thermoelectric element and is formed to generate power by using the thermal energy emitted by the first balancing circuit; a second balancing circuit which is formed to supply the power generated by the thermoelectric module to at least one secondary battery; a low voltage charging line which connects the both ends of the thermoelectric module with the second balancing circuit and supplies the power generated by the thermoelectric module to the second balancing circuit; and a control unit which calculates the charging state of the plurality of secondary batteries, determines a secondary battery to be discharged and a secondary battery to be charged based on the calculated charging state, controls the first balancing circuit connected with the secondary battery to be discharged and the second balancing circuit connected with the secondary battery to be charged, and performs a balancing between the secondary battery to be discharged and the secondary battery to be charged.

Description

[0001] Apparatus and method for cell balancing [0002]

The present invention relates to a cell balancing apparatus and method, and more particularly, to a cell balancing apparatus and method for equalizing charge of at least one secondary battery using a thermoelectric element.

In recent years, demand for portable electronic products such as notebook computers, video cameras, and portable telephones has been rapidly increased, and development of batteries, robots, and satellites for energy storage has been accelerated. Thus, a high performance rechargeable battery Researches are being actively conducted.

The lithium secondary battery is free from charge / discharge because it has almost no memory effect compared with a nickel-based secondary battery. In addition, The self-discharge rate is very low and the energy density is high.

Batteries are used in a variety of applications, such as electric powered vehicles or smart grid systems, where battery-intensive applications often require large capacities. In order to increase the capacity of the battery pack, there may be a method of increasing the capacity of the secondary battery, that is, the battery cell itself. However, in this case, there is a disadvantage that the capacity increase effect is not large and the size of the secondary battery is physically limited, Respectively. Therefore, a battery pack in which a plurality of battery modules are connected in series and in parallel is widely used.

A difference in capacity performance between secondary batteries arises due to intrinsic characteristics, differences in manufacturing environment, multiplicity of application of the system, etc., due to elapsed use time of the battery modules constituting the battery pack, The difference in terminal voltage of the corresponding module or the state of charge (SOC) difference due to the difference in the voltage of the corresponding module is generated.

Secondary batteries constituting the battery module may not have the same electrochemical characteristics. Also, as the number of charging / discharging cycles of the battery module increases, the degradation degree of each secondary battery varies, so that the performance deviation of the secondary batteries may become larger. Thus, while the battery module is charged and discharged, the charging states of the respective secondary batteries can be raised or lowered at different speeds.

When a plurality of secondary batteries having such a performance difference are driven as one battery module, the charging or discharging ability of the entire battery module is limited by the specific secondary battery whose performance is degraded, the battery module is aged, Problems may arise.

BACKGROUND ART [0002] Conventionally, in order to solve a charging state deviation between secondary batteries, a BUCK balancing which forcibly discharges a secondary battery having a relatively high charging state has been mainly used. Buck balancing, however, has wasted energy in the balancing process. Also, if the buck balancing is performed, the charging can not be performed during the buck balancing, and the charging time required until the battery module is fully charged has become long.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a cell balancing apparatus and method capable of efficiently performing secondary electrical balancing using a thermoelectric element.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It is also to be understood that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations thereof.

According to another aspect of the present invention, there is provided an apparatus for balancing charge of at least one secondary battery in a battery module including a plurality of secondary batteries, A first balancing circuit configured to receive power from the secondary battery and convert the supplied power into heat energy and discharge the heat energy; A thermoelectric module having at least one thermoelectric element, the thermoelectric module being configured to generate power using the thermal energy emitted by the first balancing circuit; A second balancing circuit configured to supply power generated by the thermoelectric module to at least one secondary battery; A low voltage charging line coupled between both ends of the thermoelectric module and the second balancing circuit, the low voltage charging line configured to supply power generated by the thermoelectric module to the second balancing circuit; And a controller configured to calculate a charging state of the plurality of secondary batteries, determine a discharge target secondary battery and a charging target secondary battery based on the calculated charging state, And a control unit controlling the second balancing circuit connected to the battery to perform balancing of the discharge target secondary battery and the charging target secondary battery.

In addition, the cell balancing apparatus according to the present invention may further include a cooling module that maintains the temperatures of the plurality of secondary batteries at a constant level.

The first balancing circuit may include a heating resistor connected to both ends of the secondary battery to convert the power supplied from the secondary battery into heat energy and discharge the heat energy, and a second balancing circuit connected in series with the heating resistor to supply power to the heating resistor. And a discharge switch configured to discharge the discharge gas.

The second balancing circuit may include a plurality of charging paths, one end of which is connected to the low-voltage charging line and the other end of which is connected to both ends of the secondary battery and are connected in parallel to each other. And at least one charging switch for opening and closing can be provided.

The thermoelectric module may also have a high temperature plate of the thermoelectric device facing the first balancing circuit and a low temperature plate of the thermoelectric device facing the cooling module.

The thermoelectric device is characterized in that the high temperature plate is in contact with the heating resistor and the low temperature plate is in contact with the cooling module and one end is connected to the positive terminal of the low voltage charging line and the other end is connected to the negative terminal of the low voltage charging line Can be configured to be connected.

The control unit may selectively open and close the discharge switch connected to the discharge target secondary battery and the charge switch connected to the charge target secondary battery.

The control unit may turn on the charging switch connected to the discharging switch connected to the discharge target secondary battery and the charging target secondary battery so that electric energy discharged from the discharging target secondary battery is supplied to the charging target secondary battery have.

According to another aspect of the present invention, there is provided a battery pack comprising a cell balancing device according to the present invention.

According to another aspect of the present invention, there is provided a method of balancing charge of at least one secondary battery in a battery module having a plurality of secondary batteries, Calculating a charged state of the battery, and determining a discharge target secondary battery and a charging target secondary battery based on the calculated state of charge; Receiving electric power from the secondary battery to be discharged, converting the supplied electric power into thermal energy and discharging the converted thermal energy; Generating power using thermal energy emitted by the thermal energy emitting step; And supplying the power generated by the power generating step to the rechargeable battery.

According to the present invention, there is an advantage in that a secondary battery having a high charging state and a secondary battery having a low charging state can be selectively discharged and charged in a configuration for selecting a secondary battery requiring discharging and charging for charge equalization between secondary batteries have.

Particularly, according to this aspect of the present invention, there is an advantage that discharge and charge can proceed simultaneously to the discharge target secondary battery and the charging target secondary battery.

According to an aspect of the present invention, there is an advantage that energy is not wasted in the cell balancing process and the speed of charge equalization between secondary cells is increased.

In addition, the present invention can have various other effects, and other effects of the present invention can be understood by the following description, and can be more clearly understood by the embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention, And should not be construed as limiting.
1 is a view schematically showing a configuration of a cell balancing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of a balancing circuit included in a cell balancing apparatus according to an embodiment of the present invention. Referring to FIG.
3 is a view schematically showing a connection structure between a thermoelectric element and some components of a cell balancing apparatus according to an embodiment of the present invention.
FIG. 4 is a view schematically illustrating a process of charging a battery module by a part of a cell balancing device according to an embodiment of the present invention.
5 is a flow chart schematically illustrating a cell balancing method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings, and the inventor should appropriately interpret the concept of the term appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

The cell balancing apparatus according to the present invention is an apparatus for equalizing the charge of the battery module (B). Here, the battery module B may include a plurality of secondary batteries 10. The cell balancing apparatus according to the present invention can equalize the charge of at least one secondary battery 10 in the battery module B having a plurality of secondary batteries 10. [ In particular, the cell balancing apparatus according to the present invention can be applied to a battery module B including a plurality of secondary batteries 10 connected in series and / or in parallel.

1 is a view schematically showing a configuration of a cell balancing apparatus according to an embodiment of the present invention.

1, a cell balancing apparatus according to the present invention includes a first balancing circuit 100, a thermoelectric module 300, a second balancing circuit 200, a low-voltage charging line L, and a control unit 400 can do.

The first balancing circuit 100 may be connected to both ends of the secondary battery 10, respectively. That is, the first balancing circuit 100 may be connected to the positive terminal and the negative terminal of each secondary battery 10, respectively. For example, as shown in FIG. 1, when the plurality of secondary batteries 10 are provided in the battery module B, the first balancing circuit 100 may be provided between both ends of each secondary battery 10, Respectively.

The first balancing circuit 100 may receive power from the secondary battery 10. In particular, the first balancing circuit 100 may receive power discharged from the at least one secondary battery 10. Here, the first balancing circuit 100 can receive power from each secondary battery 10 through a path connected to both ends of each secondary battery 10.

The first balancing circuit 100 may be configured to convert the power supplied from the secondary battery 10 into heat energy and discharge the heat energy. Particularly, the first balancing circuit 100 can convert the electric power discharged from the at least one secondary battery 10, that is, the electric energy, into heat energy, and emit the converted heat energy. For example, the first balancing circuit 100 can heat air by releasing thermal energy into the air. Alternatively, the first balancing circuit 100 may deliver thermal energy to other components of the cell balancing device according to the present invention.

The thermoelectric module 300 may include one or more thermoelectric elements. Here, the thermoelectric element can be realized as a kind of semiconductor element that uses a Seebeck effect in which an electromotive force is generated by the temperature difference between the opposed portions.

The thermoelectric module 300 may be configured to generate power using the thermal energy emitted by the first balancing circuit 100. In particular, the thermoelectric module 300 may be configured to generate a temperature difference between the two surfaces of the thermoelectric element by using thermal energy supplied from the first balancing circuit 100. Accordingly, the thermoelectric module 300 can generate an electromotive force through the thermoelectric element using the temperature difference.

The second balancing circuit 200 may be configured to supply the power generated by the thermoelectric module 300 to at least one secondary battery 10. Particularly, the second balancing circuit 200 can receive power through the electromotive force generated by the thermoelectric element. That is, the second balancing circuit 200 can be connected to both ends of the thermoelectric element to receive power from the thermoelectric element.

In addition, the second balancing circuit 200 may be connected to both ends of each secondary battery 10 to supply power to each secondary battery 10. That is, the second balancing circuit 200 may be connected to the positive terminal and the negative terminal of each secondary battery 10, respectively. For example, as shown in the configuration of FIG. 1, when a plurality of secondary batteries 10 are provided in the battery module B, the second balancing circuit 200 may be configured such that both ends of each secondary battery 10 Respectively. With this configuration, the second balancing circuit 200 can transmit the electric power supplied from the thermoelectric element to at least one secondary battery 10.

The low-voltage charging line (L) may connect both ends of the thermoelectric module (300) and the second balancing circuit (200). 1, the low-voltage charging line L may electrically connect between the positive terminal of the thermoelectric module 300 and the positive terminal of the second balancing circuit 200. For example, as shown in FIG. The low-voltage charging line L may electrically connect the negative terminal of the thermoelectric module 300 and the negative terminal of the second balancing circuit 200. With such a configuration, the low-voltage charging line L can supply the power generated by the thermoelectric module 300 to the second balancing circuit 200. That is, the low voltage charging line L can transmit the power applied to both ends of the thermoelectric module 300 to both ends of the second balancing circuit 200.

Preferably, the low-voltage charging line L may include a transformer 800, as shown in the configuration of FIG.

The transformer 800 may be located between the second balancing circuit 200 and the thermoelectric module 300. Here, the transformer 800 can reduce the power supplied from the thermoelectric module 300 to a level at which the at least one secondary battery 10 can be charged. Here, the power conversion ratio of the transformer 800 may be determined according to the number of the secondary batteries 10 to be charged through the low-voltage charging line L. [ For example, the transformer 800 may be implemented using variable transformer elements commonly used in the art. For example, the transformer 800 can adjust the power conversion ratio by controlling the number of coils wound around the conductor according to the control signal of the controller 400. [

The controller 400 may calculate the state of charge of the plurality of secondary batteries 10. For this, the cell balancing apparatus according to the present invention may include a voltage measuring unit 710, a current measuring unit 730, and a temperature measuring unit 750, as shown in the configuration of FIG.

The voltage measuring unit 710 may be electrically connected to the controller 400 so as to exchange electric signals. The voltage measuring unit 710 measures the voltage between both ends of the battery module B with a time interval under the control of the controller 400 and outputs a signal indicating the measured voltage level to the controller 400 . At this time, the control unit 400 can determine the voltage of each battery module B from the signal output from the voltage measuring unit 710. [ For example, the voltage measuring unit 710 may be implemented using a voltage measuring circuit commonly used in the art. The circuit configuration of the voltage measuring unit 710 for measuring the voltage of each battery module B will be obvious to those skilled in the art and will not be described in detail.

The current measuring unit 730 may be electrically connected to the controller 400 so as to exchange electric signals. The current measuring unit 730 repeatedly measures the magnitude of the charging current or the discharging current of each battery module B with a time interval under the control of the controller 400 and outputs a signal indicating the magnitude of the measured current to the controller 400). At this time, the controller 400 can determine the magnitude of the current from the signal output from the current measuring unit 730. For example, the current measuring unit 730 may be implemented using a hall sensor or a sense resistor commonly used in the art. The Hall sensor or sense resistor may be installed in the line through which the current flows. The circuit configuration of the current measuring unit 730 for measuring the charging current or the discharging current of each battery module B will be apparent to those skilled in the art and will not be described in detail.

The temperature measuring unit 750 may be electrically connected to the controller 400 so as to exchange electric signals. The temperature measuring unit 750 repeatedly measures the temperature of each battery module B at intervals of time and outputs a signal indicating the measured temperature to the controller 400. At this time, the control unit 400 can determine the temperature of each battery module B from the signal output from the temperature measuring unit 750. For example, the temperature measuring unit 750 may be implemented using a thermocouple commonly used in the art. The circuit configuration of the temperature measuring unit 750 for measuring the temperature of each battery module B will be apparent to those skilled in the art and will not be described in detail.

The control unit 400 controls the voltage measurement value, the current measurement value, and the temperature measurement value for at least one secondary battery 10 received from the voltage measurement unit 710, the current measurement unit 730 and the temperature measurement unit 750, The charging state of each secondary battery 10 can be calculated and monitored. That is, the control unit 400 may calculate and monitor the respective state of charge (SOC) during charging or discharging of at least one secondary battery 10. [

In one embodiment of the present invention, the control unit 400 can estimate the state of charge of each secondary battery 10 by integrating the charging current and the discharging current of each secondary battery 10. Here, the initial value of the charged state when charging or discharging of each secondary battery 10 is started can be determined by using the OCV of each secondary battery 10 measured before the charging or discharging starts. For this, the controller 400 may include an open-voltage-charge state look-up table that defines a charge state for each open-circuit voltage, and may map a charge state corresponding to an open-circuit voltage of each secondary battery 10 from a lookup table.

In another embodiment of the present invention, the controller 400 may calculate the state of charge of each secondary battery 10 using the extended Kalman filter. The extended Kalman filter refers to a mathematical algorithm for adaptively estimating the state of charge of the secondary battery 10 using the voltage, current, and temperature of the secondary battery 10. Herein, estimation of the state of charge using the extended Kalman filter can be performed, for example, by Gregory L. Plett, "Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs Parts 1, 2 and 3" (Journal of Power Source 134, 2004, p. 252-261).

The state of charge of each secondary battery 10 may be determined by other known methods capable of estimating the state of charge by selectively utilizing voltage, current, and temperature of each secondary battery 10 in addition to the current integration method or the extended Kalman filter described above .

More preferably, the control unit 400 can determine the SOC usage area of each secondary battery 10. [ In particular, the control unit 400 can determine the SOC lower limit value and the SOC upper limit value for each secondary battery 10 based on the state of each secondary battery 10, and determine the use area of each secondary battery 10. [ For example, the control unit 400 can determine the use area of each secondary battery 10 based on the voltage, current, and temperature of each secondary battery 10. For example, when three secondary batteries 10 are provided in the battery module B, the control unit 400 can determine the SOC usage area of the first secondary battery to be 20% to 80%. Further, the SOC use area of the second secondary battery can be determined to be 35% to 75%. In addition, the SOC usage area of the third secondary battery can be determined to be 40% to 90%.

The control unit 400 can calculate the charging state of each secondary battery 10 and determine the discharge target secondary battery and the charging target secondary battery based on the calculated charging state. That is, the discharge target secondary battery may be a secondary battery 10 in which the charging state of the secondary battery 10 is larger than a preset upper limit value. The charging target secondary battery may be a secondary battery 10 in which the charging state of the secondary battery 10 is smaller than a preset lower limit value. For example, when the predetermined upper limit value is 80% and the preset lower limit value is 20%, the controller 400 determines that the secondary battery 10 whose charging state is greater than 80% is the secondary battery to be discharged, The secondary battery 10 smaller than 20% can be determined as the secondary battery to be charged.

The control unit 400 may control the secondary battery 10 to discharge the secondary battery 10 if the secondary battery 10 is in a state of charge equal to or higher than the upper limit of the SOC based on the SOC usage area of the secondary battery 10, It can be determined by the target secondary battery. If the state of charge of the secondary battery 10 is equal to or lower than the SOC lower limit value, the control unit 400 can determine the secondary battery 10 to be a rechargeable object secondary battery. For example, as in the above-described example, the SOC usage area of the first secondary battery is 20% to 80%, the SOC usage area of the second secondary battery is 35% to 75% The control unit 400 can determine the first secondary battery to be the discharge target secondary battery when the state of charge of the first secondary battery is 80%. Also, the controller 400 can determine the second secondary battery as the charging target secondary battery when the charging state of the second secondary battery is 30%. In addition, the control unit 400 can determine the third secondary battery to be the charging target secondary battery when the charging state of the third secondary battery is 40%.

The controller 400 may control the first balancing circuit 100 connected to the discharge target secondary battery and the second balancing circuit 200 connected to the rechargeable battery. Accordingly, the control unit 400 can perform balancing of the discharge target secondary battery and the charging target secondary battery. This will be described later in more detail with reference to Figs. 2 to 5.

Preferably, the cell balancing apparatus according to the present invention may further include a cooling module 500, as shown in the configuration of FIG.

The cooling module 500 may be configured to maintain the temperatures of the plurality of secondary batteries 10 constant. That is, the cooling module 500 can keep the temperatures of the plurality of secondary batteries 10 constant. For example, the cooling module 500 may have a water-cooled or air-cooled structure to maintain a constant temperature of a plurality of secondary batteries 10 provided in the battery module B. Here, the cooling module 500 may be located at one side of the thermoelectric module 300. That is, the thermoelectric module 300 may be positioned between the first balancing circuit 100 and the cooling module 500. With this configuration, the thermoelectric module 300 can generate electromotive force by using the temperature difference between the cooling module 500 on one side and the first balancing circuit 100 on the other side.

With such a configuration, the cell balancing device according to the present invention generates a higher electromotive force by further increasing the temperature difference between the high-temperature plate and the low-temperature plate of the thermoelectric module by locating the cooling module on one side of the thermoelectric module, There is an advantage to be able to do.

More preferably, the cell balancing device according to the present invention may further include a storage module 600, as shown in the configuration of FIG.

The storage module 600 may be configured to store electrical energy. In particular, the storage module 600 may include an energy storage device to store electrical energy generated from the thermoelectric module 300. For example, the storage module 600 may include at least one capacitor. Here, the storage module 600 may be connected to both ends of the thermoelectric module 300. For example, the positive terminal of the storage module 600 may be electrically connected to the positive terminal of the thermoelectric module 300, as shown in FIG. In addition, the negative terminal of the storage module 600 may be electrically connected to the negative terminal of the thermoelectric module 300.

According to an embodiment of the present invention, in the aspect of the present invention, when there is no secondary battery to be discharged and only the secondary battery is to be charged, the cell balancing device according to the embodiment of the present invention charges the electric energy stored in the storage module 600 Can be supplied to the target secondary battery.

In addition, in the cell balancing apparatus according to another embodiment of the present invention, when there is no secondary battery to be charged and only the secondary battery to be discharged exists, energy to be supplied from the secondary battery to be discharged may be stored in the storage module 600.

When the electromotive force generated by the thermoelectric module 300 is greater than the energy required by the secondary battery to be discharged, the cell balancing apparatus according to another embodiment of the present invention may be configured such that the energy to be supplied to the secondary battery May be stored in the storage module 600.

When the electromotive force generated by the thermoelectric module 300 is smaller than the energy required by the secondary battery to be discharged, the cell balancing device according to another embodiment of the present invention may be configured to reduce the electromotive force generated in the thermoelectric module 300 and / The energy stored in the storage module 600 can be supplied to the discharge target secondary battery.

Accordingly, the cell balancing apparatus according to the present invention is advantageous in that energy can be efficiently distributed by using the storage module 600 to enhance energy efficiency.

Further, preferably, the low-voltage charging line L may include a plurality of control switches SW, as shown in the configuration of Fig.

The plurality of control switches SW may include a control first switch SW1, a control second switch SW2, and a control third switch SW3.

The control first switch SW1 is connected to a node N to which one end of the thermoelectric module 300, one end of the second balancing circuit 200 and one end of the storage module 600 are connected in common, It can be located between once. 1, the control first switch SW1 is connected to the positive terminal of the thermoelectric module 300, the positive terminal of the second balancing circuit 200, and the positive terminal of the storage module 600, And may be located between the node N to which the terminals are commonly connected and the positive terminal of the thermoelectric module 300. [

The control second switch SW2 may be located between one end of the second balancing circuit 200 and the node N. [ For example, as shown in the configuration of Fig. 1, the control second switch SW2 may be located between the anode terminal of the second balancing circuit 200 and the node N. [

The control third switch SW3 may be located between one end of the storage module 600 and the node N. [ For example, as shown in the configuration of Fig. 1, the control third switch SW3 may be located between the anode terminal of the storage module 600 and the node N. [

The control unit 400 can selectively control the opening and closing of the control first switch SW1, the control second switch SW2 and the control third switch SW3. That is, the control unit 400 can selectively transmit a turn-on or turn-off command to the control first switch SW1, the control second switch SW2, and the control third switch SW3, respectively.

FIG. 2 is a schematic diagram of a balancing circuit included in a cell balancing apparatus according to an embodiment of the present invention. Referring to FIG.

2, a first balancing circuit 100 according to the present invention includes a plurality of discharge paths D1, D2, D3, and D4 connected to a plurality of secondary cells 11, 12, 13, can do.

Preferably, the plurality of discharge paths D1, D2, D3, and D4 may include a heating resistor 130 and a discharge switch 110, respectively, as shown in the configuration of FIG.

The heating resistor 130 may be connected to both ends of the secondary battery 10 to convert the power supplied from the secondary battery 10 into heat energy and discharge the heat energy. The discharging switch 110 may be connected in series with the heating resistor 130 to supply power to the heating resistor 130.

2, the discharge first path D1 is connected to both ends of the first secondary battery 11 and is connected to both the discharge first switch 111 and the heat generating first resistor 131, . ≪ / RTI > Here, the discharging first switch 111 and the exothermic first resistor 131 may be connected in series. Similarly, the discharging second path D2 may be connected to both ends of the second secondary battery 12 to include the discharging second switch 112 and the discharging second resistance 132. [ Here, the discharging second switch 112 and the exothermic second resistor 132 may be connected in series. Similarly, the discharge third path D3 and the discharge fourth path D4 are connected to both ends of the third secondary battery 13 and the fourth secondary battery 14, respectively, and are connected to the discharge third switch 113, And a discharging fourth switch 114, a heating third resistor 133, and a heating fourth resistor 134, respectively. Here, the discharge third switch 113 and the exothermic third resistor 133 may be connected in series. Further, the fourth switch 114 and the fourth resistor 134 may be connected in series. Although not shown in FIG. 2, when the N secondary batteries 10 are connected in series, the discharge fifth path to the discharge N path may have a similar configuration.

The control unit 400 may output a signal capable of individually controlling the turn-on or turn-off of the discharge switch 110 provided in the plurality of discharge paths D1, D2, D3, and D4 . Accordingly, the control unit 400 can discharge at least one secondary battery 10 of the plurality of secondary batteries 11, 12, 13, and 14 individually.

The second balancing circuit 200 according to the present invention may include a plurality of charging paths C1, C2, C3, C4 connected to the plurality of secondary cells 11, 12, 13, 2, the second balancing circuit 200 is provided between the low-voltage charging line L and the plurality of secondary batteries 11, 12, 13, And the other side may be connected to the plurality of secondary cells 11, 12, 13,

Here, the plurality of charging paths (C) include a plurality of secondary batteries (10, 12, 13, 14) so as to selectively connect the at least one secondary battery (10) And may be connected to the batteries 11, 12, 13, and 14, respectively. At this time, the charging path C may be connected at one end to the low-voltage charging line L and at the other end to both ends of the secondary battery 10.

2, the second balancing circuit 200 includes a charging first path C1, a charging second path C2, a charging third path C3, and a charging fourth And a path C4. Here, the charging first path C1 may connect both ends of the low voltage charging line L and both ends of the first secondary battery 11. Similarly, the charging second path C2 can connect both ends of the low voltage charging line L and both ends of the second secondary battery 12. [ The charging third path C3 and the charging fourth path C4 can connect between both ends of the low voltage charging line L and both ends of the third and fourth secondary batteries 13 and 14. [ Although not shown in FIG. 2, when the N secondary batteries 10 are connected in series, the charging fifth path to the charging N path may have a similar configuration.

Further, the plurality of charge paths (C1, C2, C3, C4) may be connected in parallel with each other. 2, the charging first path C1, the charging second path C2, the charging third path C3 and the charging fourth path C4 are connected to the low-voltage charging line (for example, L in parallel with each other.

Preferably, the plurality of charging paths C1, C2, C3, and C4 may each include a charging switch 210, as shown in the configuration of FIG. The charging switch 210 may be configured to selectively open and close the current path. Particularly, the charging path C may include a charging switch 210 connected to the positive terminal of the secondary battery 10. For example, as shown in the configuration of FIG. 2, the charging first path C1 may include a charging first switch 211 connected to the positive terminal of the first secondary battery 11. Similarly, the charging second path C2 may include a charging second switch 212 connected to the positive terminal of the second secondary battery 12. [ Likewise, the charging third path C3 and the charging fourth path C4 may include the charging third switch 213 and the charging fourth switch 214, respectively. Although not shown in FIG. 2, when the N secondary batteries 10 are connected in series, the charging fifth path to the charging N path may have a similar configuration.

Preferably, the control unit 400 further includes a signal capable of individually controlling the turn-on or turn-off of the plurality of charge switches 210 provided in the plurality of charge paths C1, C2, C3, and C4 Can be output. Accordingly, the control unit 400 can individually connect the at least one secondary battery 10 and the low-voltage charging line L through at least one charging path C.

More preferably, the controller 400 selectively opens and closes the discharging switch 110 connected to the discharge target secondary battery and the charging switch 210 connected to the charging target secondary battery. For example, in the embodiment of Fig. 2, the first secondary battery 11 and the second secondary battery 12 of the plurality of secondary batteries 11, 12, 13, and 14 are determined as the secondary battery to be discharged, When the first secondary battery 13 and the fourth secondary battery 14 are determined to be the secondary batteries to be charged, the controller 400 controls the first secondary battery 11 and the second secondary battery 12, The switch 111 and the discharging second switch 112 may be turned on and the charging first switch 211 and the charging second switch 212 may be turned off. The control unit 400 turns on the third charging switch 213 and the charging fourth switch 214 connected to the third secondary battery 13 and the fourth secondary battery 14 and turns on the discharging third switch 213 113 and the discharge fourth switch 114 can be turned off.

With this configuration of the present invention, there is an advantage that the secondary battery 10 having a high charging state is selectively discharged and the secondary battery 10 having a low charging state can be selectively charged. Therefore, according to this aspect of the present invention, there is an advantage that the charging state of the entire battery module B can be uniformly maintained.

In addition, the cell balancing apparatus according to an embodiment of the present invention can simultaneously perform discharging of at least one secondary battery 10 and charging of at least one secondary battery 10. That is, the cell balancing apparatus can simultaneously discharge and charge the discharge target secondary battery and the charging target secondary battery by using the charging path C and the discharging path D shown in the embodiment of FIG. Therefore, according to this aspect of the present invention, there is an advantage that the charge equalization speed of the battery module B is increased.

3 is a view schematically showing a connection structure between a thermoelectric element and some components of a cell balancing apparatus according to an embodiment of the present invention. Here, portions that are different from the above-described embodiment will be mainly described, and detailed description about portions that can be applied to the same or similar descriptions of the foregoing embodiments will be omitted.

Referring to FIG. 3, the thermoelectric module 300 according to the present invention may include one or more thermoelectric elements 310. 3, the thermoelectric element 310 may include the high temperature plates 311_1 and 312_1 on one side and the low temperature plates 311_2 and 312_2 on the other side.

Preferably, the thermoelectric device 310 according to the present invention may include an electrically conductive plate, a P-type semiconductor, and an N-type semiconductor between the high temperature plates 311_1 and 312_1 and the low temperature plates 311_2 and 312_2. The configuration of the thermoelectric element 310 that generates the electromotive force by using the temperature difference between the high temperature plates 311_1 and 312_1 and the low temperature plates 311_2 and 312_2 is obvious to those skilled in the art and thus a detailed description thereof will be omitted.

The high-temperature plates 311_1 and 312_1 and the low-temperature plates 311_2 and 312_2 may be formed of a ceramic plate, which is an electrically insulating material. Thereby, the high-temperature plates 311_1 and 312_1 and the low-temperature plates 311_2 and 312_2 can electrically insulate the heating resistor 130, the thermoelectric element 310, and the cooling module 500 from each other.

The thermoelectric element 310 is connected to the first balancing circuit 100 and the low temperature plate 314 so that the high temperature plates 311_1 and 312_1 are directed toward the first balancing circuit 100 and the low temperature plates 311_2 and 312_2 are directed toward the cooling module 500. [ May be located between the plates 311_2 and 312_2. Particularly, the thermoelectric element 310 is connected to the first balancing circuit 100 so that the high-temperature plates 311_1 and 312_1 are in contact with the heating resistor 130 and the low-temperature plates 311_2 and 312_2 are in contact with the cooling module 500 Temperature plates 311_2 and 312_2.

The thermoelectric element 310 may be configured such that one end is connected to the positive terminal of the low voltage charging line L and the other end is connected to the negative terminal of the low voltage charging line L. [ For example, as shown in the configuration of FIG. 3, a plurality of thermoelectric elements 311 and 312 may be connected in series to the thermoelectric element 310. The positive terminal of the thermoelectric element 310 may be connected to the positive terminal of the low voltage charging line L and the negative terminal of the thermoelectric element 310 may be connected to the negative terminal of the low voltage charging line L. [

Preferably, the cooling module 500 according to the present invention may be configured such that, as shown in the configuration of FIG. 3, a flow path is provided therein, and cooling water or air flows through the flow path.

With such a configuration, the cell balancing apparatus according to the present invention has an advantage that the temperature difference between the high-temperature plate and the low-temperature plate of the thermoelectric device 310 is further increased, thereby increasing the charging efficiency of the secondary battery 10.

FIG. 4 is a view schematically illustrating a process of charging a battery module by a part of a cell balancing device according to an embodiment of the present invention. Here, portions that are different from the above-described embodiment will be mainly described, and detailed description about portions that can be applied to the same or similar descriptions of the foregoing embodiments will be omitted.

Referring to FIG. 4, a controller 400 according to the present invention can determine a rechargeable battery among a plurality of rechargeable batteries 10 provided in the battery module B. In addition, the control unit 400 can supply the power supplied from the thermoelectric module 300 to the rechargeable battery via the second balancing circuit 200 connected to both ends of the rechargeable rechargeable battery.

To this end, the control unit 400 can selectively open and close the plurality of control switches SW provided in the low-voltage charging line L. [

For example, in the embodiment of Fig. 4, the first secondary battery 11 and the second secondary battery 12 are determined as the charging target secondary battery, and the third secondary battery 13 is determined as the discharge target secondary battery The controller 400 according to an embodiment of the present invention can supply the power generated from the thermoelectric module 300 to the second balancing circuit 200 through the low voltage charging line L. [ Specifically, the control unit 400 can turn the control first switch SW1 and the control second switch SW2 on and turn off the control third switch SW3. The control unit 400 may connect both ends of the thermoelectric module 300 and both ends of the second balancing circuit 200 to supply the power generated by the thermoelectric module 300 to the second balancing circuit 200 have. 2, the controller 400 selectively opens and closes the charge switch 210 provided in the second balancing circuit 200 to selectively connect the first secondary battery 11 and the second secondary battery 12 And the both ends of the thermoelectric module 300 can be electrically connected to each other.

The control unit 400 also turns on the discharge switch 110 connected to the discharge target secondary battery and the charge switch 210 connected to the charging target secondary battery so that the electric energy discharged from the discharge target secondary battery is supplied to the charging target secondary battery Can be turned on. 2 and 4, the controller 400 turns on the third switch 113 connected to the third secondary battery 13 to discharge the third secondary battery 13 So that the electric energy can be supplied to the exothermic third resistor 133. At this time, the exothermic third resistor 133 can discharge the electric energy supplied from the third secondary battery 13 as thermal energy. Thermal energy emitted by the third exothermic resistor 133 can then be converted into electrical energy through the thermoelectric module 300. [ The control unit 400 turns on the charging first switch 211 and the charging second switch 212 connected to the first secondary battery 11 and the second secondary battery 12 to turn on the first secondary battery 11 11 and the second secondary battery 12 and both ends of the thermoelectric module 300 can be electrically connected to each other.

With this configuration, the cell balancing apparatus according to the present invention is advantageous in that it can increase the energy efficiency by recycling the energy consumed in the conventional cell balancing process.

The controller 400 according to another embodiment of the present invention may supply the power stored in the storage module 600 to the second balancing circuit 200 through the low voltage charging line L. [ Specifically, the control unit 400 can turn the control first switch SW1 and the control third switch SW3 on and turn off the control second switch SW2. The control unit 400 may connect both ends of the storage module 600 and both ends of the second balancing circuit 200 to supply the power stored in the storage module 600 to the second balancing circuit 200. For this purpose, the control unit 400 may charge the storage module 600 in advance. For example, the control unit 400 may pre-charge the storage module 600 by turning the control first switch SW1 and the control third switch SW3 on and turning off the control second switch SW2 .

With this configuration, the cell balancing apparatus according to the present invention has an advantage that the energy consumed in the conventional cell balancing process can be stored and reused even when the rechargeable battery is not present. That is, the cell balancing apparatus according to the present invention can store energy in the storage module 600 without consuming energy even if the rechargeable rechargeable battery is not present in the discharge, and if there is only the rechargeable rechargeable battery without the rechargeable rechargeable battery There is an advantage that the charging target secondary battery can be charged using the energy stored in the storage module 600. [

In addition, the controller 400 according to another embodiment of the present invention can supply power from the thermoelectric module 300 and the storage module 600 to the second balancing circuit 200. Specifically, the control unit 400 can turn on both the control first switch SW1, the control second switch SW2, and the control third switch SW3. The control unit 400 may connect both ends of the thermoelectric module 300 and both ends of the storage module 600 to both ends of the second balancing circuit 200. That is, the control unit 400 connects the both ends of the thermoelectric module 300 and both ends of the storage module 600 in parallel, so that the electric power generated by the thermoelectric module 300 and the electric power stored in the storage module 600 2 balancing circuit 200 as shown in FIG.

With this configuration, the cell balancing apparatus according to the present invention has an advantage that the power that can be supplied to the secondary battery 10 can be increased as compared with the case where only the thermoelectric element is used.

In order to perform the operations as described above, the control unit 400 may include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, and / As shown in FIG.

Preferably, the control unit 400 may include at least one memory. That is, the control unit 400 may include at least one memory. The memory may store programs and data associated with various operations performed by the cell balancing device in advance.

The cell balancing apparatus according to the present invention may be provided in the battery pack itself. That is, the battery pack according to the present invention may include the cell balancing apparatus according to the present invention described above. Here, the battery pack may include a plurality of secondary batteries 10, a cell balancing device, electrical equipment (BMS, relays, fuses, etc.), and a case. In this configuration, at least a part of each component of the cell balancing apparatus according to the present invention can be implemented by supplementing or adding the function of the configuration included in the conventional battery pack. For example, the control unit 400 of the cell balancing apparatus according to the present invention may be implemented by a BMS (Battery Management System) provided in the battery pack.

5 is a flow chart schematically illustrating a cell balancing method according to an embodiment of the present invention. In FIG. 5, the execution subject of each step may be each component of the cell balancing apparatus according to the present invention described above.

5, the cell balancing method according to the present invention includes a charging / discharging secondary cell determination step S100, a thermal energy discharging step S110, a power generation step S120, and a charging step S130 .

First, in the charge / discharge target secondary battery determination step S100, the charge states of a plurality of secondary batteries are calculated, and the discharge target secondary battery and the charge target secondary battery are determined based on the calculated charge state. Subsequently, in the thermal energy discharge step (S110), the discharge target secondary battery is discharged, and the electric power supplied from the discharge target secondary battery is converted into heat energy and discharged. Subsequently, in the power generation step (S120), electric power is generated by using the thermal energy emitted by the thermal energy emission step. Subsequently, in the charging step (S130), the electric power generated by the electric power generating step is supplied to the charging target secondary battery, and the charging target secondary battery is charged.

Preferably, the cell balancing method according to the present invention may include a storing step prior to the charging step (S130). In the storing step, the power generated in the power generating step (S120) may be stored. Subsequently, in the charging step (S130), the power stored in the storing step may be supplied to the rechargeable battery.

In addition, in the thermal energy discharging step S110 and the charging step S130, a discharging switch connected to the discharge target secondary battery and a charging switch connected to the charging target secondary battery can be selectively opened and closed.

Further, in the thermal energy discharging step (S110) and the charging step (S130), the discharging switch connected to the discharging target secondary battery and the charging target secondary battery are connected so that the electric energy discharged from the discharging target secondary battery is supplied to the charging target secondary battery The charging switch can be turned on.

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 understood that various modifications and changes may be made without departing from the scope of the appended claims.

In the present specification, the terms 'unit' and 'module' are used, such as 'control unit', 'measuring unit', and 'thermoelectric module', but they are logical constitutional units, It should be apparent to those skilled in the art that this does not represent a component that must be physically separated.

10: Secondary battery
100: first balancing circuit
110: Discharge switch
130: Heating resistance
200: second balancing circuit
210: Charging switch
300: thermoelectric module
310: thermoelectric element
311_1, 312_1: High temperature plate
311_2, 312_2: low temperature plate
400:
500: cooling module
600: storage module
710: voltage measuring unit
730: Current measuring unit
750: Temperature measuring unit
800: Transformer
B: Battery module
C: Charging path
D: Discharge path
L: Low-voltage charging line

Claims (10)

1. A cell balancing device for equalizing charge of at least one secondary battery in a battery module having a plurality of secondary batteries,
A first balancing circuit connected to both ends of the secondary battery to receive power from the secondary battery, convert the supplied power into heat energy, and discharge the heat energy;
A thermoelectric module having at least one thermoelectric element, the thermoelectric module being configured to generate power using the thermal energy emitted by the first balancing circuit;
A second balancing circuit configured to supply power generated by the thermoelectric module to at least one secondary battery;
A low voltage charging line coupled between both ends of the thermoelectric module and the second balancing circuit, the low voltage charging line configured to supply power generated by the thermoelectric module to the second balancing circuit; And
Calculating a charging state of the plurality of secondary cells, determining a secondary battery to be discharged and a secondary battery to be charged on the basis of the calculated state of charge, and controlling the first balancing circuit and the secondary battery, And a control unit for controlling the second balancing circuit connected to the charging target secondary battery and the charging target secondary battery,
The cell balancing device comprising:
The method according to claim 1,
Further comprising a cooling module configured to maintain a constant temperature of the plurality of secondary batteries.
3. The method of claim 2,
The first balancing circuit may include a heating resistor connected to both ends of the secondary battery to convert the power supplied from the secondary battery into heat energy and discharge the heat energy and to supply power to the heating resistor in series with the heating resistor. And a discharge switch.
The method of claim 3,
The second balancing circuit includes a plurality of charging paths, one end of which is connected to the low voltage charging line and the other end of which is connected to both ends of the secondary battery and are connected in parallel with each other. Wherein at least one charging switch is provided.
5. The method of claim 4,
Wherein the thermoelectric module is such that a hot plate of the thermoelectric element faces the first balancing circuit and a cold plate of the thermoelectric element faces the cooling module.
6. The method of claim 5,
The thermoelectric element is arranged such that the high temperature plate contacts the heating resistor and the low temperature plate contacts the cooling module and has one end connected to the positive terminal of the low voltage charging line and the other end connected to the negative terminal of the low voltage charging line The cell balancing device comprising:
The method according to claim 6,
Wherein the control unit selectively opens and closes the discharge switch connected to the discharge target secondary cell and the charge switch connected to the charge target secondary battery.
8. The method of claim 7,
The control unit turns on the charging switch connected to the discharging switch and the charging target secondary battery connected to the discharging target secondary battery so that electric energy discharged from the discharging target secondary cell is supplied to the charging target secondary battery Cell balancing device.
A battery pack comprising the cell balancing device according to any one of claims 1 to 8.
A cell balancing method for equalizing charge of at least one secondary battery in a battery module having a plurality of secondary batteries,
Calculating charge states of the plurality of secondary cells and determining a discharge target secondary battery and a charging target secondary battery based on the calculated state of charge;
Receiving electric power from the secondary battery to be discharged, converting the supplied electric power into thermal energy and discharging the converted thermal energy;
Generating power using thermal energy emitted by the thermal energy emitting step; And
Supplying power generated by the power generating step to the rechargeable battery;
The cell balancing method comprising:

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