KR102124186B1 - Apparatus for balancing battery stack - Google Patents

Abstract

The present invention discloses a technique for balancing a battery stack using a resonant circuit.
Battery stack balancing apparatus according to an embodiment of the present invention, a device for balancing a battery stack including a plurality of battery modules, a cell balancing unit for balancing a plurality of battery cells included in each battery module; A module balancing unit for balancing the plurality of battery modules; And a control unit controlling the cell balancing unit and the module balancing unit. At least one of the cell balancing unit and the module balancing unit may be implemented as a resonance circuit.

Description

Battery stack balancing device {Apparatus for balancing battery stack}

The present invention relates to a technique for balancing a battery, and more particularly, to an apparatus for balancing a battery stack including two or more battery modules using a resonance circuit.

A secondary battery having high applicability according to the product family and having electrical characteristics such as high energy density is commonly used in electric vehicles (EV, Electric Vehicle) or hybrid vehicles (HV, Hybrid Vehicle) driven by electric driving sources as well as portable devices. It is applied.

This secondary battery is attracting attention as a new energy source for eco-friendliness and energy efficiency improvement, in that not only does not generate any by-products due to the use of energy, as well as a primary advantage that can dramatically reduce the use of fossil fuels.

On the other hand, the battery pack applied to an electric vehicle is usually composed of a plurality of battery cells connected in series and / or parallel structure, the battery cell includes a positive electrode current collector, a negative electrode current collector, a separator, an active material, an electrolyte, It is possible to repeatedly charge and discharge by the electrochemical reaction between the components.

In addition, the battery pack is generally measured for electrical characteristics such as power supply control, current, voltage, charge/discharge control, equalization control of voltage, state of charge (SOC) estimation, state of health (SOH) estimation, etc. It comprises a BMS (Battery Management System) to perform the.

On the other hand, the performance of a plurality of battery cells constituting the battery pack may vary due to various reasons. In addition, voltage imbalance between battery cells occurs due to variations in performance of the battery cells.

When the battery pack is used in a state in which such an imbalance occurs, the performance of the battery pack depends on the deteriorated battery cell, resulting in a problem that the performance of the entire battery pack is limited. In addition, the deteriorated battery cell has a characteristic in which the deterioration of the performance is further accelerated, so that if the deteriorated battery cell is left unattended, the life of the battery pack is rapidly reduced.

In order to solve this problem, in the related art, passive balancing is performed to selectively discharge resistors at both ends of the battery cell to discharge the battery cell, or a low voltage is applied to the battery cell with a high voltage through a capacitor. Active balancing has been performed to deliver to the battery cell.

However, the conventional passive balancing technology consumes power by using a resistor to perform balancing, so there is a problem of wasting power, and the conventional active balancing technology using a capacitor is used to generate a voltage difference between a battery cell and a capacitor. There is a problem in that it takes a considerable amount of time to perform balancing, for example, a switching operation must be repeatedly performed.

The present invention was created to solve the problems of the conventional balancing technology, and an object of the present invention is to provide a balancing device that enables power transmission to be performed quickly while balancing without wasting power.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by examples of the present invention. In addition, it will be readily appreciated that the objects and advantages of the present invention can be realized by means and combinations thereof.

Battery stack balancing apparatus according to various embodiments of the present invention for achieving the above object is as follows.

(One). An apparatus for balancing a battery stack including a plurality of battery modules, comprising: a cell balancing unit for balancing a plurality of battery cells included in each battery module; A module balancing unit for balancing the plurality of battery modules; And a control unit that controls the cell balancing unit and the module balancing unit.

(2). The method of claim 1, wherein the module balancing unit comprises: a first series resonant circuit including a first capacitor and a first inductor connected in series with the first capacitor; A first polarity change circuit connected to the first capacitor in parallel, including a second inductor and a first polarity change switch connected to the second inductor in series and selectively turned on or off; One end is electrically connected to a plurality of nodes each formed between a low potential end of the battery stack, a high potential end of the battery stack, and a plurality of battery modules connected in series, and the other end is connected to the first series resonant circuit First transmission lines; And a plurality of first transmission switches respectively installed on the plurality of first transmission lines and selectively turned on or off. The control unit includes the plurality of first transmission switches and the first Battery stack balancing device characterized in that it controls the polarity change switch.

(3). The battery stack balancing device of claim 2, wherein the cell balancing unit includes a plurality of cell balancing units provided for each battery module.

(4). The cell balancing unit of claim 3, wherein the cell balancing unit comprises: a second series resonant circuit including a second capacitor and a third inductor connected in series with the second capacitor; A second polarity changing circuit connected to the second capacitor in parallel, including a fourth inductor and a second polarity changing switch connected to the fourth inductor in series and selectively turned on or off; One end is electrically connected to a plurality of nodes each formed between a low potential end of the battery module, a high potential end of the battery module, and a plurality of battery cells connected in series, and the other end is connected to the second series resonant circuit. Second transmission lines; And a plurality of second transmission switches which are respectively installed on the plurality of second transmission lines and selectively turned on or off. The control unit may include the plurality of second transmission switches and the second. Battery stack balancing device characterized in that it controls the polarity change switch.

(5). The battery stack balancing apparatus according to (4), wherein the other end of each second transmission line constituting the plurality of second transmission lines is alternately connected to one end or the other end of the second series resonant circuit.

(6). The battery stack balancing device according to (5), wherein the control unit controls the plurality of second transfer switches to perform zero current switching or zero voltage switching according to half of the resonant cycle of the second series resonant circuit. .

(7). The method according to (5), wherein the control unit, when the second polarity change switch is turned on, the zero current switching or zero in accordance with half the resonant cycle of the second parallel resonance circuit formed by the second capacitor and the fourth inductor. The battery stack balancing device, characterized in that to control the second polarity change switch so that the voltage switching.

(8). The method according to (5), wherein the controller compares the polarity of the voltage of at least one battery cell to which the second series resonant circuit is to be powered and the polarity of the voltage charged in the second capacitor to switch the second polarity change switch. And controlling the plurality of second transfer switches.

(9). The method according to (8), the control unit, if the voltage polarity of at least one battery cell to which the second series resonant circuit is to be powered and the polarity of the voltage charged in the second capacitor are the same, the second polarity changing switch is turned on. The battery stack balancing device, characterized in that to control to turn on, and turn off all of the plurality of second transfer switch.

(10). The method according to (5), wherein the controller compares the polarity of the voltage of at least one battery cell to which the second series resonant circuit will supply power with the polarity of the voltage charged in the second capacitor, and the second polarity change switch and Battery stack balancing device, characterized in that for controlling the plurality of second transfer switch.

(11). The method according to (10), the control unit, if the voltage polarity of at least one battery cell to which the second series resonant circuit will supply power and the voltage polarity of the voltage charged in the second capacitor are the same, turn the second polarity change switch. Off, turn on the two second transfer switches connected to both ends of the at least one battery cell to which the second series resonant circuit will supply power, and turn on the other second transfer switches except the two second transfer switches Battery stack balancing device characterized in that to control to turn off.

(12). The method according to (10), the control unit, if the voltage polarity of the voltage charged in the second capacitor and the voltage of the at least one battery cell to which the second series resonant circuit supplies power is different, the second polarity change switch is turned on. And controlling to turn off all of the plurality of second transfer switches.

(13). In (3), the cell balancing unit, discharge resistance; And a discharge switch connected in series to the discharge resistor, wherein the control unit controls the discharge switch.

(14). The method according to any one of (2) to (13), characterized in that the other end of each of the first transmission lines constituting the plurality of first transmission lines is alternately connected to one end or the other end of the first series resonance circuit. Battery stack balancing device.

(15). The battery stack balancing device according to claim 14, wherein the controller controls the plurality of first transfer switches to be zero current switching or zero voltage switching according to half of the resonant cycle of the first series resonant circuit. .

(16). The method according to (14), the control unit, when the first polarity change switch is turned on, zero current switching or zero in accordance with half the resonance cycle of the first parallel resonance circuit formed by the first capacitor and the second inductor The battery stack balancing device, characterized in that for controlling the first polarity change switch to be a voltage switch.

(17). The method according to claim 14, wherein the control unit compares the polarity of the voltage of at least one battery module to which the first series resonant circuit is to be powered and the polarity of the voltage charged in the first capacitor to switch the first polarity change switch. And controlling the plurality of first transfer switches.

(18). The method according to (17), wherein the control unit, if the voltage polarity of at least one battery module to which the first series resonant circuit is to be powered and the voltage polarity of the voltage charged in the first capacitor are the same, turn the first polarity change switch. Turning on, and controlling the battery stack to turn off all of the plurality of first transfer switch, the battery stack balancing device.

(19). The method according to claim 14, wherein the control unit compares the polarity of the voltage of at least one battery module to which the first series resonant circuit will supply power with the polarity of the voltage charged in the first capacitor, and the first polarity changing switch and Battery stack balancing device, characterized in that for controlling the plurality of first transfer switch.

(20). The method according to (19), wherein the control unit, if the voltage polarity of at least one battery module to which the first series resonant circuit will supply power and the voltage polarity of the voltage charged in the first capacitor are the same, turns the first polarity change switch. Off, turn on two first transfer switches connected to both ends of the at least one battery module to which the first series resonant circuit will supply power, and turn on the remaining first transfer switches except for the two first transfer switches Battery stack balancing device characterized in that to control to turn off.

(21). The method according to (19), the control unit, if the voltage polarity of the voltage charged in the first capacitor and the voltage of at least one battery module to which the first series resonant circuit is to supply power to the first polarity change switch is turned on And controlling to turn off all of the plurality of first transfer switches.

(22). A battery pack comprising the battery stack balancing device according to any one of (1) to (21).

(23). An electric vehicle comprising the battery stack balancing device according to any one of (1) to (21).

According to an aspect of the present invention, since the balancing is performed using a series resonant circuit, since zero voltage or zero current switching is performed according to a half cycle of the series resonant circuit, the voltage difference between the battery module or the battery cell and the resonant circuit is maximized. Thus, balancing can be done efficiently and quickly.

In addition, according to another aspect of the present invention, by using a polarity changing circuit connected in parallel to the capacitor provided in the series resonance circuit, it is possible to reduce the number of transmission lines and transmission switches.

In addition, according to another aspect of the present invention, a parallel resonant circuit is formed by turning on a polarity change switch of a polarity changing circuit, and balancing can be more efficiently achieved through resonance of the parallel resonant circuit.

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

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described below, and thus the present invention is described in such drawings. It is not limited to interpretation.
1 is a view showing a state in which the battery stack balancing apparatus according to an embodiment of the present invention is connected to the battery stack.
FIG. 2 is a circuit diagram at time t0, showing a state in which the first transmission switch adjacent to the first battery module is turned on.
3 is a graph showing the voltage of the first capacitor over time.
4 is a circuit diagram at a time when a half period of the first series resonant circuit has elapsed from t0, the first transmission switch adjacent to the first battery module is turned off, and the first transmission switch adjacent to the third battery module is turned on. It is a diagram showing the state.
5 is a graph showing the voltage of the first capacitor over time.
FIG. 6 is a circuit diagram at a time when a half cycle of the first series resonant circuit has elapsed from t0, showing a state in which the first transmission switch adjacent to the first battery module is turned off and the first polarity change switch is turned on. .
7 is a graph showing the voltage of the first capacitor over time.
8 is a circuit diagram at a time when a half period of the first parallel resonant circuit has elapsed from t1, showing a state in which the first polarity change switch is turned off and the first transfer switch adjacent to the second battery module is turned on. .
9 is a graph showing the voltage of the first capacitor over time.
10 is a view showing a state of a circuit diagram before changing the polarity of the voltage of the first capacitor.
11 is a view showing a state of a circuit diagram after changing the polarity of the voltage of the first capacitor.
12 is a graph showing the voltage of the first capacitor over time.
13 is a view showing a state of a circuit diagram before changing the polarity of the voltage of the first capacitor.
14 is a view showing a state of a circuit diagram after changing the polarity of the voltage of the first capacitor.
15 is a graph showing the voltage of the first capacitor over time.
16 is a diagram illustrating a state in which a battery stack balancing device according to another embodiment of the present invention is connected to a battery stack.
17 is a view showing a battery stack balancing apparatus according to another embodiment of the present invention.
18 is a view showing a cell balancing unit according to an embodiment of the present invention.
19 is a view showing a cell balancing unit according to another embodiment of the present invention.
20 is a flowchart illustrating a battery stack balancing method according to an embodiment of the present invention.
21 is a flowchart illustrating a battery stack balancing method according to another embodiment of the present invention.
22 is a flowchart illustrating a battery stack balancing method according to another 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, the terms or words used in the present specification and claims should not be interpreted as being limited to ordinary or dictionary meanings, and the inventor appropriately explains the concept of terms in order to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in this specification is only one of the most preferred embodiments of the present invention and does not represent all of the technical spirit of the present invention, and thus can replace them at the time of application. It should be understood that there may be equivalents and variations.

In addition, in the description of the present invention, when it is determined that detailed descriptions of related known configurations or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

Throughout the specification, when a part “includes” a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise specified. Also, terms such as “control unit” described in the specification mean a unit that processes at least one function or operation, and may be implemented by hardware or software, or a combination of hardware and software.

In addition, throughout the specification, when a part is "connected" to another part, it is not only "directly connected", but also "indirectly connected" with another element in between. Includes.

1 is a view showing a state in which the battery stack balancing device according to an embodiment of the present invention is connected to the battery stack.

Referring to FIG. 1, the battery stack 10 includes a plurality of battery modules 20. The battery stack 10 is an aggregate of a plurality of battery modules 20. Here, the battery modules 20 may be connected in series with each other. In the embodiment of FIG. 1, the number of the battery modules 20 is shown as three, but the number of the battery modules 20 is not limited thereto.

The battery module 20 includes battery cells. The battery module 20 is a unit battery cell 30 or an aggregate of two or more battery cells 30. At this time, the battery cells 30 may be connected to each other in series or in parallel, or may be connected in series and in parallel. In the embodiment of Figure 1, the battery module 20, two battery cells 30 are connected in series, the number and connection relationship of the battery cells 30 is not limited thereto.

Referring to FIG. 1 again, the battery stack balancing device 100 includes a first series resonant circuit 110, a first polarity changing circuit 120, and a plurality of first transmission lines 131, 132, 133, and 134. , A plurality of first transmission switches (141, 142, 143, 144) and a control unit (not shown).

The first series resonant circuit 110 may be formed by connecting a capacitor and an inductor in series. In this specification, the capacitor included in the first series resonant circuit 110 is referred to as a first capacitor 111, and the inductor included in the first series resonant circuit 110 is referred to as a first inductor 112. . The capacitance of the first capacitor 111 and the inductance of the first inductor 112 may be selected to an appropriate value in consideration of power to be charged and a resonance period.

The first polarity changing circuit 120 may be connected in parallel to the first capacitor 111. The first polarity changing circuit 120 includes an inductor and a switch. In this specification, the inductor included in the first polarity changing circuit 120 is referred to as a second inductor 121, and the switch included in the first polarity changing circuit 120 is referred to as a first polarity changing switch 122. do. The first polarity change switch 122 may be selectively turned on or off according to a control signal of a control unit to be described later. The first polarity change switch 122 may be implemented with various switching elements. According to one embodiment, the first polarity change switch 122 may be implemented as a MOSFET. The first polarity change switch 122 may be connected in series with the second inductor 121. When the first polarity change switch 122 is turned on, the second inductor 121 is connected in parallel with the first capacitor 111. That is, when the first polarity change switch 122 is turned on, the second inductor 121 and the first capacitor 111 may form a parallel resonance circuit. Here, the parallel resonant circuit formed by the second inductor 121 and the first capacitor 111 may be referred to as a first parallel resonant circuit. Meanwhile, when the first polarity changing switch 122 is turned off, the parallel connection between the second inductor 121 and the first capacitor 111 is released. In addition, the capacitance of the first capacitor 111 and the inductance of the second inductor 121 may be selected as appropriate values in consideration of a resonance period or the like. Preferably, the inductance of the second inductor 121, the inductance of the first inductor 112 so that the resonant cycle of the first parallel resonant circuit 110 is shorter than the resonant cycle of the first series resonant circuit 110. Can be set to a smaller value.

The plurality of first transmission lines (131, 132, 133, 134), a plurality of nodes (N1, N2, N3, N4) formed in the battery stack 10 and the first series resonant circuit 110 electrically Connect with. Here, the plurality of nodes (N1, N2, N3, N4) formed in the battery stack 10, two nodes (N1, N4) formed on both ends of the battery stack 10, and the battery modules 20 It means the nodes (N2, N3) formed between each. In other words, the plurality of nodes N1, N2, N3, and N4 formed in the battery stack 10 are formed at the node N1 formed at the low potential end of the battery stack 10 and at the high potential end of the battery stack 10. It means the nodes N2 and N3 respectively formed between the node N4 and two adjacent battery modules 20. One end of the plurality of first transmission lines (131, 132, 133, 134) is electrically connected to the plurality of nodes (N1, N2, N3, N4). Further, the other ends of the plurality of first transmission lines 131, 132, 133, and 134 are electrically connected to the first series resonant circuit 110. In other words, one end of any one of the first transmission lines is connected to any one node formed in the battery stack 10, and the other end of the first transmission line is connected to the first serial resonance circuit 110. .

In this case, the other end of each of the first transmission lines is connected to one end of the first series resonant circuit 110 or is connected to the other end of the first series resonant circuit 110. Accordingly, any one of the battery modules 20 may be electrically connected to the first series resonance circuit 110 by first transmission lines connected to both ends of the one of the battery modules 20. Preferably, the other end of each first transmission line constituting the plurality of first transmission lines 131, 132, 133, and 134 may be alternately connected to one end and the other end of the first series resonant circuit 110. have. That is, as illustrated in FIG. 1, the other end of each first transmission line connected to a plurality of nodes is connected to one end or the other end of the first series resonant circuit 110, but the direction of the low potential node is low or high. The potential node may be alternately connected to one end or the other end of the first series resonant circuit 110 along the direction of the high potential node.

Further, at least one switch may be installed on each of the first transmission lines 131, 132, 133, and 134. In this specification, switches installed on each of the first transmission lines 131, 132, 133, and 134 are referred to as first transmission switches 141, 142, 143, and 144.

That is, the plurality of first transmission switches 141, 142, 143, and 144 may be installed on the plurality of first transmission lines 131, 132, 133, and 134. The first transfer switches 141, 142, 143, and 144 may be implemented with various switching elements, and according to an embodiment, the first transfer switches 141, 142, 143, and 144 may be implemented as MOSFETs. . The first transmission switches 141, 142, 143, and 144 may be selectively turned on or off according to a control signal of a control unit to be described later. The plurality of first transmission switches 141, 142, 143, and 144 are selectively turned on and off to at least one battery module 20 and a first series resonant circuit through at least two first transmission lines Let 110 be electrically connected.

The control unit (not shown) may control the first polarity change switch 122 and the plurality of first transfer switches 141, 142, 143, and 144. The control unit may be in communication with the first polarity change switch 122 and the plurality of first transmission switches 141, 142, 143, and 144 to transmit a control signal to control a switching operation. According to an embodiment, the first polarity change switch 122 and the plurality of first transfer switches 141, 142, 143, and 144 are implemented as MOSFETs, and the controller selectively selects a voltage at the gate terminal of the MOSFET. You can apply to control the switch.

Preferably, the battery stack balancing device may further include a voltage measuring unit for measuring the voltage of the battery cell and/or the battery module, and the voltage measuring unit may be implemented by a voltage sensor or the like.

In addition, preferably, the battery stack balancing device, using the measured battery cell and / or the voltage of the battery module to calculate the voltage that is the target of the balancing, or further includes a calculation unit for performing the calculation required for balancing Can be. The calculation unit may be implemented by a calculation means such as a microprocessor, and the calculation unit may be implemented in an integrated form with a controller.

Hereinafter, a balancing operation between the battery modules will be described using the battery stack balancing apparatus 100 according to an embodiment of the present invention with reference to FIG. 2 and the like.

For convenience of description, the three battery modules 20 will be referred to as a first battery module 21, a second battery module 22, and a third battery module 23, respectively. And, as shown in the figure, the voltages of the three battery modules are indicated by V1, V2 and V3, respectively, and V1, V2 and V3 all have positive values. And, as shown in the figure, the voltage of the first capacitor 111 is represented by Vc. The voltage Vc of the first capacitor 111 may have a negative value unlike V1, V2, and V3. In addition, V1, V2, V3 and Vc are values that change with time.

First, a process of transferring power stored in the first battery module 21 to the first series resonant circuit 110 will be described.

FIG. 2 is a circuit diagram at time t0, showing a state in which the first transfer switch adjacent to the first battery module is turned on, and FIG. 3 is a graph showing the voltage of the first capacitor over time. In other words, FIG. 3 can be said to be a graph showing the voltage of the first capacitor in the circuit formed by the controller at time t0.

First, referring to FIG. 2, the controller (not shown), in order to transfer the power stored in the first battery module 21 to the first series resonant circuit 110, the first battery module 21 at the time t0 The first transmission switches 141 and 142 adjacent to are turned on, the remaining first transmission switches 143 and 144 are turned off, and the first polarity change switch 122 is turned off. In other words, the control unit turns on two first transfer switches 141 and 142 connected to both ends of the first battery module 21, and the remaining first except the two first transfer switches 141 and 142. The transfer switches 143 and 144 are turned off, and the first polarity change switch 122 is turned off.

As a result, the circuit as shown in Figure 2 is configured, the first battery module 21, the first transmission line 132, the first series resonant circuit 110, the closing of the first transmission line 131 A furnace is formed. The power stored in the first battery module 21 is transmitted to the first series resonant circuit 110 by LC series resonance. Assuming that the initial energy is not stored in the capacitor and the inductor at t0, which is an arbitrary time point in which the circuit shown in FIG. 2 is formed, the voltage of the first capacitor 111 after t0 is represented by the graph shown in FIG. 3. That is, in a series resonant circuit in which a capacitor, an inductor and a voltage source are connected in series, the voltage of the capacitor vibrates as shown in FIG. 3 according to the resonance period. At this time, the voltage charged in the first capacitor 111 has a maximum value according to the half cycle of the first series resonant circuit 110. In other words, t0+Ts/2, t0+Ts+Ts/2, t0+2*Ts+Ts/2, t0+3*Ts+Ts/2, ... to the first capacitor 111 at the time The voltage to be charged has a maximum value as a value (2*V1i) that is twice the initial voltage V1i of the first battery module 21 as a voltage source. Meanwhile, the initial voltage V1i of the first battery module 21 may be referred to as V1(t0) which is the voltage of the first battery module 21 at the time t0.

The control unit may include a plurality of first transmission switches 141, 142, 143, 144 and a first polarity change switch to be zero voltage switching or zero current switching in accordance with half of the resonant cycle of the first series resonant circuit 110. 122). Preferably, the control unit may perform zero-voltage switching by controlling the switches to change the switching at a time t0+Ts/2, which is a half-cycle that is the earliest time from the time t0 when charging starts.

Next, a description will be given of a process in which the first series resonant circuit 110 transmits the power received from the first battery module 21 to the third battery module 23.

4 is a circuit diagram at a time when a half period of the first series resonant circuit has elapsed from t0, the first transfer switch adjacent to the first battery module is turned off, and the first transfer switch adjacent to the third battery module is turned on. 5 is a graph showing a state, and FIG. 5 is a graph showing the voltage of the first capacitor over time. In other words, FIG. 4 is a diagram illustrating a state in which the control unit performs zero voltage switching when a half cycle of the first series resonant circuit has elapsed after the circuit diagram of FIG. 2 is formed, and FIG. 5 is according to the switching control of the control unit It can be said that the voltage of the first capacitor 111 in the changed circuit is a graph showing the passage of time.

Referring to FIG. 3 again, at a time when charging is completed (t0+Ts/2), the first capacitor 111 of the first series resonant circuit 110 has a voltage that is twice the voltage of the first battery module 21 (2*V1i) is charged. Meanwhile, the voltage polarity of the third battery module 23 connected to the first series resonant circuit 110 and to be supplied with power is the same as that of the first capacitor 111. More specifically, assuming that the first series resonant circuit 110 is electrically connected to the third battery module 23, the polarity of the voltage of the third battery module 23 is the voltage of the first capacitor 111 It is the same as the polarity. That is, assuming that the first series resonant circuit 110 is electrically connected to the third battery module 23, the high potential of the third battery module 23 and the high potential of the first capacitor 111 are connected to each other The low potential end of the third battery module 23 and the low potential end of the first capacitor 111 are connected to each other (see FIG. 1 and the like).

The voltage polarity of the third battery module 23 to be supplied with power from the series resonant circuit 110 and the voltage polarity of the first capacitor 111 are the same, and the magnitude of the voltage charged in the first capacitor 111 is third. Since the voltage of the battery module 23 is approximately twice the voltage, even if the first series resonant circuit 110 is connected to the third battery module 23 as it is, the third battery module from the first series resonant circuit 110 ( 23) The power transmission to the can be made naturally.

Therefore, the control unit does not change the voltage polarity charged in the first capacitor 111, and controls the power stored in the first series resonant circuit 110 to be supplied to the third battery module 23. That is, as shown in FIG. 4, the control unit turns on two first transfer switches 143 and 144 connected to both ends of the third battery module 23, and the two first transfer switches 143, The first transfer switches 141 and 142 other than 144) are turned off, and the first polarity change switch 122 is controlled to be turned off.

As a result, power stored in the first series resonant circuit 110 may be transmitted to the third battery module 23. As shown in FIG. 3, the voltage of the first capacitor 111 at the time t0+Ts/2 is twice the initial voltage V1i of the first battery module 21, and is 2*V1i. In addition, 2*Vli is an initial voltage value of the first capacitor 111 in the circuit (FIG. 4) formed at the time t0+Ts/2. Accordingly, the voltage of the first capacitor 111 changes as shown in FIG. 5 in the process of transferring the power stored in the first series resonant circuit 110 to the third battery module 23. During the period from t0+Ts/2 to t0+Ts in FIG. 5, power stored in the first series resonant circuit 110 is transmitted to the third battery module 23.

Separately, a description will be given of a process in which the first series resonant circuit 110 transfers power received from the first battery module 21 to the second battery module 22.

FIG. 6 is a circuit diagram when a half period of the first series resonant circuit has elapsed from t0, showing a state in which the first transmission switch adjacent to the first battery module is turned off and the first polarity change switch is turned on. , FIG. 7 is a graph showing the voltage of the first capacitor 111 over time. In other words, FIG. 6 is a diagram illustrating a state in which the control unit performs zero voltage switching when a half cycle of the first series resonant circuit has elapsed after the circuit diagram of FIG. 2 is formed, and FIG. 7 is according to the switching control of the control unit It can be said that the voltage of the first capacitor in the changed circuit is a graph showing the passage of time.

Referring to FIG. 3 again, at the time when charging is completed (t0+Ts/2), the first capacitor 111 of the first series resonant circuit 110 becomes twice the initial voltage of the first battery module 21. The voltage (2*Vli) is charged. Meanwhile, the voltage polarity of the second battery module 22 connected to the first series resonant circuit 110 and to be supplied with power is different from the voltage polarity of the first capacitor 111. More specifically, assuming that the first series resonant circuit 110 is electrically connected to the second battery module 22, the polarity of the voltage of the second battery module 22 is the voltage of the first capacitor 111 It is different from the polarity. That is, assuming that the first series resonant circuit 110 is electrically connected to the second battery module 22, the high potential of the second battery module 22 is connected to the low potential of the first capacitor 111, , It is connected to the low potential end of the second battery module 22 and the high potential end of the first capacitor 111 (see FIG. 1 and the like). The reason why the voltage polarity of the first capacitor 111 is different from the voltage polarity of the second battery module 22 is that a plurality of first transmission lines 131, 132, 133, and 134 alternately have a first series resonant circuit. It is because it is connected to (110).

Since the voltage polarity of the first battery 111 and the voltage polarity of the second battery module 22 to receive power from the first series resonant circuit 110 are different, the first series resonant circuit 110 is the second battery module In the case of being directly connected to (22), power transmission may be performed from the second battery module 22 to the first series resonant circuit 110, unlike the balancing intention. Therefore, in order to transfer power stored in the first series resonant circuit 110 to the second battery module 22, it is necessary to change the polarity of the voltage charged in the first capacitor 111.

Therefore, instead of directly connecting the first series resonant circuit 110 to the second battery module 22, the control unit controls the polarity of the voltage charged in the first capacitor 111 through the first polarity changing circuit 120. And control the first series resonant circuit 110 and the second battery module 22 to be connected.

That is, as illustrated in FIG. 6, the control unit controls the first polarity change switch 122 to be turned on, and turns off the plurality of first transmission switches 141, 142, 143, and 144. . That is, the control unit turns on the first polarity change switch 122 at the time when charging is finished (t0+Ts/2), and turns all of the plurality of first transfer switches 141, 142, 143, and 144. Turned off to form a resonance circuit by the first capacitor 111 and the second inductor 121 of the first polarity changing circuit 120. As shown in FIG. 3, the voltage of the first capacitor 111 at the time t0+Ts/2 is twice the initial voltage V1i of the first battery module 21, and is 2*V1i. In addition, 2*Vli becomes an initial voltage value of the first capacitor 111 in the circuit (FIG. 6) formed at the time t0+Ts/2. That is, the voltage stored in the first capacitor 111 is 2*Vli at the time when the first parallel resonance circuit formed by the first capacitor 111 and the second inductor 121 is formed, which is illustrated in FIG. 6. .

Meanwhile, the first parallel resonance circuit formed by the first capacitor 111 and the second inductor 121 repeats vibration according to the resonance cycle of the parallel resonance circuit. Since the power source such as a battery module is not connected to the first parallel resonance circuit, the voltage of the first capacitor 111 is changed in polarity with time as shown in FIG. 7. That is, the polarity of the voltage of the first capacitor 111 changes each time a half cycle elapses.

The polarity of the voltage of the first capacitor 111 is compared with the polarity of the voltage of the first capacitor 111 at the time when the first parallel resonance circuit is formed (t1=t0+Ts/2). It has the opposite polarity according to the half cycle. In other words, when t1+Tp/2, t1+Tp+Tp/2, t1+2*Tp+Tp/2, t1+3*Tp+Tp/2, ..., the first capacitor 111 The polarity of the voltage has a polarity opposite to that of the voltage of the first capacitor 111 at the time when the first parallel resonance circuit is formed. Accordingly, the control unit may include a plurality of first transmission switches 141, 142, 143, 144 and a first polarity change switch 122 to perform zero voltage switching or zero current switching according to half of the resonance cycle of the first parallel resonance circuit. ) Is good to control. Preferably, the controller controls the power stored in the first series resonant circuit 110 at a time (t1+Tp/2) at which the half cycle, which is the earliest time from the time (t1) when the first parallel resonant circuit is formed, has elapsed. The zero voltage switching may be performed by controlling the plurality of first transmission switches 141, 142, 143, and 144 and the first polarity change switch 122 so as to be delivered to the battery module 22.

That is, the control unit turns the first polarity change switch 122 as shown in FIG. 8 at a time (t1+Tp/2) when a half period of the parallel resonant cycle has elapsed from the time t1 when the first parallel resonance circuit is formed. Turn off, turn on the two first transfer switches 142, 143 connected to both ends of the second battery module 22, and the first transfer switches other than the two first transfer switches 142, 143 (141, 144) is controlled to turn off so that the first series resonant circuit 110 is connected to the second battery module 22 in a state where the polarity of the first capacitor 111 is changed. Meanwhile, the polarity of the voltage of the first capacitor 111 is changed, so that the voltage of the first capacitor 111 at the time t1+Tp/2 becomes -2*V1i. In addition, -2*Vli is a voltage value charged in the first capacitor 111 when the first series resonant circuit 110 is connected to the second battery module 22.

Meanwhile, since the polarity of the voltage of the first capacitor 111 has been changed, power stored in the first series resonant circuit 110 may be transmitted to the second battery module 22. That is, the first series resonant circuit 110 may charge the second battery module 22. The change in voltage of the first capacitor 111 in the process of transferring the power stored in the first series resonant circuit 110 to the second battery module 22 is illustrated in FIG. 9. More specifically, during the period from t1+Tp/2 to t1+Tp/2+Ts/2 in FIG. 9, power stored in the first series resonant circuit 110 is transmitted to the second battery module 22.

Hereinafter, an operation for solving a problem in which charging of the first capacitor 111 is not efficiently performed by the charge remaining in the first capacitor 111 in the process of balancing is described.

Referring back to FIGS. 5 and 9, the voltage of the first capacitor 111 is not 0 at the time t0+Ts of FIG. 5, and the first capacitor 111 at the time t1+Tp/2+Ts/2 of FIG. 9 It can be seen that the voltage of) is also not zero. This is because a part of charge remains in the first capacitor 111 in the process of transferring power from the first series resonant circuit 110 to the battery module. As described above, when charge remains in the first capacitor 111, a charging voltage is present in the first capacitor 111, so power transmission from the battery module to the first capacitor 111 may not be smoothly performed.

First, it will be described after the time t0 + Ts of FIG. 5.

At the time t0+Ts, the voltage of the first capacitor 111 is Va. As can be seen from FIG. 5, Va is a value greater than zero. In this state, when the first series resonant circuit 110 needs to be connected to the first battery module 21 or the third battery module 23 in order to perform balancing, the electric charge remaining in the first capacitor 111 Due to the power transmission may not be made smoothly. This is because the polarity of the voltage of the first battery module 21 or the third battery module 23 and the voltage of the first capacitor 111 are the same. More specifically, assuming that the first series resonant circuit 110 is electrically connected to the first battery module 21 or the third battery module 23, the first battery module 21 or the third battery module Since the polarity of the voltage of (23) and the polarity of the voltage of the first capacitor 111 are the same, power transfer from the first battery module 21 or the third battery module 23 to the first series resonant circuit 110 This may not be performed smoothly. In other words, the voltage charged in the first capacitor 111 may interfere with power transmission from the battery module having the same polarity as the first capacitor 111. In this case, the control unit controls the switches so that the polarity of the voltage of the first capacitor 111 is changed so that power transmission from the battery module to the first series resonant circuit 110 can be performed smoothly.

Fig. 10 is a diagram showing the state of the circuit diagram before changing the polarity of the voltage of the first capacitor, and Fig. 11 is a diagram showing the state of the circuit diagram after changing the polarity of the voltage of the first capacitor. It is a graph showing the voltage of the first capacitor over time.

The control unit controls to turn on the first polarity change switch 122 and turn off all of the plurality of first transfer switches 141, 142, 143, and 144, at a time t0+Ts, as shown in FIG. do. Since the voltage of the first capacitor 111 at time T0+Ts is Va, as shown in FIG. 10, the controller maintains this switching state until time t0+Ts+Tp/2, and t0+Ts+Tp/2 The voltage of the first capacitor 111 is controlled to be -Va at the time. That is, the control unit changes the polarity of the voltage of the first capacitor 111 so that the voltage of the first capacitor 111 is from Va to -Va. Then, the control unit, t0 + Ts + Tp / 2 at the time of the first series resonant circuit 110 and the first battery module 21 or the third battery module 23 is connected to the first polarity change switch 122 and Control the first transfer switch. For example, in order to transfer the power stored in the third battery module 23 to the first series resonant circuit 110, the control unit, as shown in FIG. 11, at t0+Ts+Tp/2 time point, the third battery module Turn on the two first transfer switches (143, 144) connected to both ends of (23), and turn the remaining first transfer switches (141, 142) except for the two first transfer switches (143, 144) It is controlled to turn off and turn off the first polarity change switch 122. As illustrated in FIG. 11, at a time t0+Tp+Tp/2, the voltage of the first capacitor 111 is -Va and the polarity is changed, so that after t0+Tp+Tp/2, the first series resonant circuit Power transfer from 110 to the third battery module 23 may be performed. The change in voltage of the first capacitor 111 during this process, that is, the process of changing the polarity of the first capacitor 111 and the process of receiving power from the third battery module 23 is t0+ of FIG. 12. It appears in the section after Ts.

On the other hand, when the first series resonant circuit 110 needs to be connected to the second battery module 22 in order to perform balancing, even if electric charges remain in the first capacitor 111, the second battery module 22 Power transmission can be made smoothly. This is because the polarity of the voltage of the second battery module 22 is different from the polarity of the voltage of the first capacitor 111. More specifically, assuming that the first series resonant circuit 110 is electrically connected to the second battery module 22, the polarity of the voltage of the second battery module 22 and the voltage of the first capacitor 111 Since the polarities of are different, power transfer from the second battery module 22 to the first series resonant circuit 110 can be smoothly performed. In other words, when the polarity of the voltage of the first capacitor 111 and the voltage of the voltage of the battery module to transfer power to the first capacitor 111 are different, the voltage charged in the first capacitor 111 is the battery module It does not interfere with the power transmission from. In this case, the control unit does not change the polarity of the first capacitor 111, and controls the switches so that the first series resonant circuit 110 and the second battery module 22 are directly connected.

Next, it will be described after the time t0 + Tp / 2 + Ts / 2 of FIG. 9.

At the time t0+Tp/2+Ts/2, the voltage of the first capacitor 111 is -Vb. As can be seen from FIG. 5, -Vb is a value less than zero. In this state, when the first series resonant circuit 110 needs to be connected to the second battery module 22 in order to perform balancing, power transfer is smoothly performed by the electric charge remaining in the first capacitor 111. You may not lose. This is because the polarity of the voltage of the second battery module 22 and the voltage of the first capacitor 111 are the same. More specifically, assuming that the first series resonant circuit 110 is electrically connected to the second battery module 22, the polarity of the voltage of the second battery module 22 and the voltage of the first capacitor 111 Because of the same polarity, power transmission from the second battery module 22 to the first series resonant circuit 110 may not be performed smoothly. In this case, the control unit controls the switches so that the polarity of the voltage of the first capacitor 111 is changed so that power transmission from the battery module to the first series resonant circuit 110 can be performed smoothly.

13 is a diagram showing the state of the circuit diagram before changing the polarity of the voltage of the first capacitor, and FIG. 14 is a diagram showing the state of the circuit diagram after changing the polarity of the voltage of the first capacitor. It is a graph showing the voltage of the first capacitor over time.

At a time t0+Tp/2+Ts/2, the control unit turns on the first polarity change switch 122 and turns on the plurality of first transfer switches 141, 142, 143, and 144, as shown in FIG. Control to turn them all off. The voltage of the first capacitor 111 at the time t0+Tp/2+Ts/2 is -Vb, as shown in FIG. 13, so that the controller controls t0+Tp/2+Ts/2+Tp/2(= This switching state is maintained until the time t0+Tp+Ts/2) so that the voltage of the first capacitor 111 becomes Vb at the time t0+Tp+Ts/2. That is, the controller changes the polarity of the voltage of the first capacitor 111 so that the voltage of the first capacitor 111 is from -Vb to Vb. Then, the control unit controls the first polarity change switch 122 and the first transfer switch so that the first series resonant circuit 110 and the second battery module 22 are connected at a time t0+Tp+Ts/2. That is, as shown in FIG. 14, at t0+Tp+Ts/2, the control unit turns on the two first transfer switches 142, 143 connected to both ends of the second battery module 22, and the two The first transfer switches 141 and 144 other than the first transfer switches 142 and 143 are turned off, and the first polarity change switch 122 is controlled to be turned off. As illustrated in FIG. 14, since the polarity of the voltage of the first capacitor 111 is changed to Vb at the time t0+Tp+Ts/2, the first series resonant circuit after t0+Tp+Tp/2 ( Power transmission from 110) to the second battery module 22 may be performed. In this process, that is, the process of changing the polarity of the first capacitor 111 and the process of receiving power from the second battery module 22, the change in the voltage of the first capacitor 111 is t0+ in FIG. 15. Tp/2+Ts/2.

Meanwhile, when the first series resonant circuit 110 needs to be connected to the first battery module 21 or the third battery module 23 in order to perform balancing, the first capacitor 111 may be charged even if charge remains. The power transfer with the one battery module 21 or the third battery module 23 can be smoothly performed. This is because the polarities of the voltages of the first battery module 21 and the third battery module 23 are different from the polarities of the voltages of the first capacitor 111. More specifically, assuming that the first series resonant circuit 110 is electrically connected to the first battery module 21 or the third battery module 23, respectively, the polarity of the voltage of the first battery module 21 And the polarity of the voltage of the first capacitor 111 is different, and the polarity of the voltage of the third battery module 23 and the voltage of the first capacitor are different, so the polarity of the first capacitor 111 is not changed. If not, the power transfer from the first battery module 21 or the third battery module 23 to the first series resonant circuit 110 can be performed smoothly. In this case, the control unit does not change the polarity of the first capacitor 111, and controls the switches so that the first series resonant circuit 110 and the first battery module 21 or the third battery module 23 are directly connected. .

On the other hand, in the above description, it has been described as an example using three battery modules, the battery stack balancing apparatus 100 according to an embodiment of the present invention is not limited by the number of battery modules. That is, even if the number of battery modules increases, the above description can be applied as it is. Those skilled in the art will be able to easily implement the battery stack balancing device 100 based on the contents disclosed herein even when the number of battery modules increases.

In addition, in the above description, the power transmission between the first series resonant circuit 110 and the battery module has been described as an example using one battery module, but the battery stack balancing apparatus 100 according to an embodiment of the present invention ) Is not limited to this. That is, in the above-described example, power transmission from the first series resonant circuit 110 or power from the first series resonant circuit 110 by electrical connection between the adjacent odd number of battery modules and the first series resonant circuit 110. It goes without saying that delivery may be performed. For example, assuming that the battery stack 10 includes seven battery modules composed of the first battery module to the seventh battery module, the control unit may include a first battery module, a second battery module, and a third battery module And the first series resonant circuit 110 to be electrically connected to transmit power stored in the first battery module, the second battery module, and the third battery module to the first series resonant circuit 110. In addition, the control unit controls the fourth battery module, the fifth battery module and the sixth battery module and the first series resonant circuit 110 to be electrically connected to the fourth battery module, the fifth battery module, and the sixth battery module. The power stored in the first series resonant circuit 110 may be transmitted. Alternatively, the control unit controls the fifth battery module, the sixth battery module, and the seventh battery module and the first series resonant circuit 110 to be electrically connected to the fifth battery module, the sixth battery module, and the seventh battery module As a result, the power stored in the first series resonant circuit 110 may be transmitted, and the first series resonant circuit 110 may also transmit power to three other adjacent battery modules. In addition, the controller changes the polarity of the voltage of the first capacitor 111 by using the first polarity changing circuit 120 as necessary during the power transfer process between the battery modules and the first series resonant circuit 110. Can be.

16 is a view showing a battery stack balancing device connected to a battery stack according to another embodiment of the present invention.

Referring to FIG. 16, the battery stack balancing device 100 according to another embodiment of the present invention, when compared to the battery stack balancing device 100 shown in FIG. 1 and the like, a consumption circuit connected in parallel to the first capacitor 111 There is only a difference in that it further includes 160. Therefore, the above descriptions can be applied as it is to describe the battery stack balancing apparatus 100 according to another embodiment of the present invention in a range that is not contradictory. Therefore, repeated descriptions of the same components will be omitted.

The consumption circuit 160 includes a resistor and a switch connected in series to the resistor. In this specification, the resistor 161 is referred to as a consumption resistor 161, and a switch 162 connected in series to the resistor is referred to as a consumption switch 162. The consumption switch 162 may be turned on or off according to a control signal from a control unit (not shown), and may be implemented with various switching elements. The consumption circuit 160 is one of other means for solving the problem that charging of the first capacitor 111 is not efficiently performed by the charge remaining in the first capacitor 111 during the balancing process. .

Referring back to FIGS. 5 and 9, the voltage of the first capacitor 111 is not 0 at the time t0+Ts of FIG. 5, and the first capacitor 111 at the time t1+Tp/2+Ts/2 of FIG. 9 It can be seen that the voltage of) is also not zero. This is because some charges remain in the first capacitor 111 in the process of transferring power from the first series resonant circuit 110 to the battery module. As described above, when electric charges remain in the first capacitor 111, a voltage difference exists in the first capacitor 111, so power transmission from the battery module to the first capacitor 111 may not be smoothly performed. Therefore, the battery stack balancing apparatus 100 according to another embodiment of the present invention may consume all of the remaining charge in the first capacitor 111 using the consumption circuit 160. Specifically, before transferring power from the battery module to the first series resonant circuit 110, the controller turns on the consuming switch 162 and turns on the first transfer switches 141, 142, 143, and 144. Turning them all off consumes all the remaining charge in the first capacitor 111. At this time, the first polarity change switch 122 may be turned on or off, but preferably, the first polarity change switch 122 is preferably turned off. Then, the control unit maintains a state in which the consumption switch 162 is turned on until the reference time elapses, and all of the first transmission switches 141, 142, 143, and 144 are turned off. In this case, the reference time may be set to a time that it can be seen that all the charge remaining in the first capacitor 111 is consumed.

17 is a view showing a battery stack balancing apparatus according to another embodiment of the present invention.

Referring to FIG. 17, a battery stack balancing device according to another embodiment of the present invention includes a cell balancing unit 300, a module balancing unit 200, and a control unit (not shown). The cell balancing unit 300 balances a plurality of battery cells included in each battery module, the module balancing unit 200 balances the plurality of battery modules, and the control unit is a cell balancing unit 300 And the module balancing unit 200 to control the battery stack to be balanced.

That is, the battery stack balancing apparatus according to another embodiment of the present invention may perform not only balancing between battery modules, but also balancing between battery cells. Further, at least one of battery module balancing and battery cell balancing may be performed by the above-described method (a method using a resonance circuit). In other words, balancing using a resonant circuit may be applied to perform balancing between battery modules and may also be applied to perform balancing between battery cells.

According to one aspect, the module balancing unit 200, a first series resonant circuit; A first polarity changing circuit; A plurality of first transmission lines; And a plurality of first transfer switches. Here, as for the configuration and operation of the first series resonant circuit, the first polarity changing circuit, the plurality of first transmission lines, and the plurality of first transmission switches, the contents described with reference to FIGS. 1 to 16 may be applied as they are. , Repetitive explanation will be omitted.

According to another aspect, the cell balancing unit 300 may include a plurality of cell balancing units 400 to perform balancing between battery cells in each battery module.

18 is a view showing a cell balancing unit according to an embodiment of the present invention. Referring to FIG. 18, the cell balancing unit 400 includes a second series resonant circuit 410; A second polarity changing circuit 420; A plurality of second transmission lines 431, 432, 433, 434; And a plurality of second transfer switches 441, 442, 443, and 444.

The second series resonant circuit 410 may be formed by connecting a capacitor and an inductor in series. In this specification, the capacitor included in the second series resonant circuit 410 is referred to as a second capacitor 411, and the inductor included in the second series resonant circuit 410 is referred to as a third inductor 412. . The capacitance of the second capacitor 411 and the inductance of the third inductor 412 may be selected as appropriate values in consideration of power to be charged and resonance period.

The second polarity changing circuit 420 may be connected in parallel to the second capacitor 411. The second polarity changing circuit 420 includes an inductor and a switch. In this specification, the inductor included in the second polarity changing circuit 420 is referred to as a fourth inductor 421, and the switch included in the second polarity changing circuit 420 is referred to as a second polarity changing switch 422. do. The second polarity change switch 422 may be selectively turned on or off according to the control signal of the aforementioned control unit. The second polarity change switch 422 may be implemented with various switching elements. The second polarity change switch 422 may be connected in series with the fourth inductor 421. When the second polarity change switch 422 is turned on, the fourth inductor 421 is connected in parallel with the second capacitor 411. That is, when the second polarity change switch 422 is turned on, the fourth inductor 421 and the second capacitor 411 may form a parallel resonance circuit. Here, the parallel resonant circuit formed by the fourth inductor 421 and the second capacitor 411 may be referred to as a second parallel resonant circuit. Meanwhile, when the second polarity change switch 422 is turned off, the parallel connection between the fourth inductor 421 and the second capacitor 411 is released. In addition, the capacitance of the second capacitor 411 and the inductance of the fourth inductor 421 may be selected as appropriate values in consideration of a resonance period or the like. Preferably, the inductance of the fourth inductor 421 is such that the resonant cycle of the second parallel resonant circuit 410 can be shorter than the resonant cycle of the second series resonant circuit 410. Can be set to a smaller value.

The plurality of second transmission lines 431, 432, 433, and 434 electrically connect the plurality of nodes M1, M2, M3, and M4 formed in the battery module and the second series resonant circuit 410. . Here, the plurality of nodes (M1, M2, M3, M4) formed in the battery module, two nodes (M1, M4) respectively formed on both ends of the battery module, and the nodes (M2, M3) respectively formed between the battery cells ). In other words, the plurality of nodes M1, M2, M3, and M4 formed in the battery module includes a node M1 formed at the low potential end of the battery module, a node M4 formed at the high potential end of the battery module, and two adjacent batteries. It means the nodes M2 and M3 respectively formed between cells. One end of the plurality of second transmission lines 431, 432, 433, and 434 is electrically connected to the plurality of nodes M1, M2, M3, and M4. Further, the other ends of the plurality of second transmission lines 431, 432, 433, and 434 are electrically connected to the second series resonant circuit 410. In other words, one end of the second transmission line is connected to any one node formed in the battery module, and the other end of the second transmission line is connected to the second serial resonance circuit 410.

At this time, the other end of each second transmission line is connected to one end of the second series resonant circuit 410 or is connected to the other end of the second series resonant circuit 410. Accordingly, any one of the battery cells may be electrically connected to the second series resonant circuit 410 by a second transmission line connected to both ends of the one of the battery cells. Preferably, the other end of each second transmission line constituting the plurality of second transmission lines 431, 432, 433, and 434 may be alternately connected to one end and the other end of the second series resonant circuit 410. have. That is, as shown in FIG. 18, the other end of each second transmission line connected to the plurality of nodes is connected to one end or the other end of the second series resonant circuit 410, but the direction of the low potential node or the low potential node in the high potential node. The potential node may be alternately connected to one end or the other end of the second series resonant circuit 410 along the direction of the high potential node.

Further, at least one switch may be installed on each of the second transmission lines 431, 432, 433, and 434. In this specification, switches installed on each second transmission line 431, 432, 433, 434 are referred to as second transmission switches 441, 442, 443, 444.

That is, the plurality of second transmission switches 441, 442, 443, and 444 may be installed on the plurality of second transmission lines 431, 432, 433, and 434. The second transfer switches 441, 442, 443, and 444 may be implemented with various switching elements. The second transmission switches 441, 442, 443, and 444 may be selectively turned on or off according to the control signal of the aforementioned control unit. The plurality of second transfer switches 441, 442, 443, and 444 are selectively turned on and off to at least one battery cell and a second series resonant circuit 410 through at least two second transfer lines. Is electrically connected.

The control unit (not shown) may control the second polarity change switch 422 and the plurality of second transfer switches 441, 442, 443, and 444. The control unit may be in communication with the second polarity change switch 422 and the plurality of second transfer switches 441, 442, 443, and 444 to transmit a control signal to control a switching operation. According to one embodiment, the second polarity change switch 422 and the plurality of second transfer switches 441, 442, 443, and 444 are implemented as a MOSFET, and the control unit selectively selects a voltage at the gate terminal of the MOSFET. You can apply to control the switch.

As described above, the second series resonant circuit 410, the second polarity changing circuit 420, the second transmission lines 431, 432, 433, 434 and the second transmission switches 441, 442, 443, 444) can be said to be substantially the same components as the first series resonant circuit, the first polarity changing circuit, the first transmission lines, and the first transmission switches, respectively. That is, in the battery stack balancing apparatus according to another embodiment of the present invention, the module balancing unit 200 and the cell balancing unit 400 differ only in whether the modules are balanced or the cells are balanced. There is no difference.

Therefore, the contents described with reference to FIGS. 2 to 16 and the like may be inferred to the cell balancing unit 400, and thus repeated description will be omitted.

The battery stack balancing apparatus according to another embodiment of the present invention described above may be divided into the following three methods according to whether the resonant circuit is used. That is, the battery stack balancing apparatus according to another embodiment of the present invention can be divided into three methods according to whether the module balancing unit 200 and the cell balancing unit 300 are implemented as a resonant circuit.

Balancing between battery modules Balancing between battery cells Method 1 use unused Method 2 unused use Method 3 use use

In the first method of Table 1, a resonant circuit is used for balancing between battery modules, but a resonant circuit is not used for balancing between battery cells. In the second method of Table 1, a resonance circuit is used for balancing between battery cells, but a resonance circuit is not used for balancing between battery modules. The balancing between the battery cells in the first method and the balancing between the battery modules in the second method may be performed by other known methods, for example, a passive balancing method.

19 is a view showing a cell balancing unit according to another embodiment of the present invention.

Referring to FIG. 19, the cell balancing unit 400 according to another embodiment of the present invention may be implemented as a discharge circuit 500. The cell balancing unit 300 includes a plurality of discharge circuits 500, and the discharge circuit 500 may be connected to each battery cell. The discharge circuit 500 may include a discharge resistor 501 and a discharge switch 502 connected in series to the discharge resistor 501. The control unit may control the discharge switch 502 to discharge the battery cells connected to the discharge circuit 500 to perform balancing among the battery cells included in the battery module.

Hereinafter, a method of balancing a battery stack through balancing between battery modules and balancing between battery cells using the above-described battery stack balancing apparatus will be described.

20 is a flowchart illustrating a battery stack balancing method according to an embodiment of the present invention. The battery stack balancing method according to an embodiment of the present invention is a method of performing balancing between battery cells and then performing balancing between battery modules.

Referring to FIG. 20, a battery stack balancing method according to an embodiment of the present invention may be performed through the following process.

First, the method prepares a battery stack balancing device including a module balancing unit 200, a cell balancing unit 300, and a control unit (S10).

Subsequently, the method measures the voltage of the battery cells included in the battery stack (S11).

Next, the method calculates the equalization voltage of the battery cells for each battery module using the measured voltage of the battery cells. That is, the method calculates a target voltage for each battery cell to equalize between the battery cells included in the battery module for each battery module (S12).

Next, the method performs the balancing between the battery cells of each battery module using the cell balancing unit 300 (S13).

Optionally, the method may measure the voltage of the battery cells included in the battery stack again (S14).

Next, the method calculates the equalization voltage of the battery module using the measured voltage of the battery cells. That is, the method calculates the target voltage for each battery module to equalize between the battery modules included in the battery stack (S15).

Next, the method performs the balancing between the battery modules using the module balancing unit 200 (S16).

Optionally, the method, after step S16, measuring the voltage of the battery cells included in the battery stack again (S17), and after the step S17, the target voltage for each battery cell included in the battery module for each battery module again The calculating step (S18), and after the step S18, using the cell balancing unit 300 may further include the step of performing the balancing between the battery cells of each battery module (S19).

21 is a flowchart illustrating a battery stack balancing method according to another embodiment of the present invention. The battery stack balancing method according to another embodiment of the present invention is a method of performing balancing between battery modules and then performing balancing between battery cells.

Referring to FIG. 21, a battery stack balancing method according to another embodiment of the present invention may be performed through the following process.

First, in the above method, a battery stack balancing device including a module balancing unit 200, a cell balancing unit 300 and a control unit is prepared (S20 ).

Subsequently, the method measures the voltage of the battery cells included in the battery stack (S21).

Next, the method calculates the equalization voltage of the battery module using the measured voltage of the battery cells. That is, the method calculates the target voltage for each battery module to equalize between the battery modules included in the battery stack (S22).

Next, the method performs the balancing between the battery modules using the module balancing unit 200 (S23).

Optionally, the method may re-measure the voltage of the battery cells included in the battery stack (S24).

Next, the method calculates the equalization voltage of the battery cells for each battery module using the measured voltage of the battery cells. That is, the method calculates a target voltage for each battery cell to equalize between the battery cells included in the battery module for each battery module (S25).

Next, the method performs the balancing between the battery cells of each battery module using the cell balancing unit 300 (S26).

22 is a flowchart illustrating a battery stack balancing method according to another embodiment of the present invention. The battery stack balancing method according to another embodiment of the present invention is a method for simultaneously performing balancing between battery modules and balancing between battery cells.

Referring to FIG. 22, a battery stack balancing method according to another embodiment of the present invention may be performed through the following process.

First, in the above method, a battery stack balancing device including a module balancing unit 200, a cell balancing unit 300 and a control unit is prepared (S30 ).

Subsequently, the method measures the voltage of the battery cells included in the battery stack (S31).

Next, the method calculates an equalizing voltage of the battery module and the battery cell using the measured voltage of the battery cells. That is, the method calculates a target voltage for each battery cell such that equalization between battery modules included in the battery stack and equalization between battery cells included in the battery module are simultaneously performed (S32).

Next, the method performs the balancing between the battery module and the battery cells using the module balancing unit 200 and the cell balancing unit 300 (S33).

According to another aspect of the present invention, the above-described battery stack balancing device 100 may be included in the battery pack. That is, the battery pack according to another aspect of the present invention may include the above-described battery stack balancing device 100. For example, the battery pack may include a battery management device, and the battery management device may include the battery stack balancing device 100 as one component.

The battery stack balancing device 100 may be included in a vehicle. That is, a vehicle according to another aspect of the present invention may include the battery stack balancing device 100 described above. For example, the vehicle may include a battery pack, and the battery stack balancing device 100 may be provided in the battery pack. As another example, the vehicle may include a vehicle control device, but the vehicle control device may be provided with a battery stack balancing device 100. On the other hand, here, the vehicle includes not only an electric vehicle or a hybrid vehicle as a transportation means using electric energy as a power source, but also a vehicle equipped with electrical equipment that is supplied with electric power.

Although the present invention has been described above by way of limited examples and drawings, the present invention is not limited by this and will be described below and the technical idea of the present invention by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the equal scope of the claims.

Features described in individual embodiments herein may be implemented in combination in a single embodiment. Conversely, various features that are described in this specification in a single embodiment may be implemented in various embodiments individually or in appropriate subcombinations.

10: battery stack
20, 21, 22, 23: battery module
30, 31, 32, 33: battery cell
100: battery stack balancing device
110: first series resonant circuit 111: first capacitor
112: first inductor 120: first polarity changing circuit
121: second inductor 122: first polarity change switch
131, 132, 133, 134: 1st transmission line
141, 142, 143, 144: first transmission switch
160: consumption circuit 161: consumption resistance 162: consumption switch
200: module balancing unit 300: cell balancing unit
400: cell balancing unit 410: second series resonant circuit
411: second capacitor 412: third inductor
420: second polarity changing circuit 421: fourth inductor
422: second polarity change switch
431, 432, 433, 434: 2nd transmission line
441, 442, 443, 444: second delivery switch
500: discharge circuit 501: discharge resistance 502: discharge switch

Claims (22)

In the apparatus for balancing the battery stack including a plurality of battery modules,
A module balancing unit for balancing the plurality of battery modules; And
Includes; a control unit for controlling the module balancing unit,
The module balancing unit,
A first series resonant circuit including a first capacitor and a first inductor connected in series with the first capacitor;
A first polarity change circuit connected to the first capacitor in parallel, including a second inductor and a first polarity change switch connected to the second inductor in series and selectively turned on or off;
One end is electrically connected to a plurality of nodes each formed between a low potential end of the battery stack, a high potential end of the battery stack, and a plurality of battery modules connected in series, and the other end is connected to the first series resonant circuit First transmission lines; And
It includes; a plurality of first transmission switches which are respectively installed on the plurality of first transmission lines and selectively turned on or off;
The other end of each first transmission line constituting the plurality of first transmission lines is alternately connected to one end or the other end of the first series resonance circuit,
The controller compares the polarity of the voltage of at least one battery module to which the first series resonant circuit is to be powered and the polarity of the voltage charged in the first capacitor, and the plurality of first transfer switches and the first. Battery stack balancing device characterized in that it controls the polarity change switch.
According to claim 1,
Further comprising a cell balancing unit for balancing a plurality of battery cells included in each battery module;
The cell balancing unit, a battery stack balancing device comprising a plurality of cell balancing unit provided for each battery module.
According to claim 2,
The cell balancing unit,
A second series resonant circuit including a second capacitor and a third inductor connected in series with the second capacitor;
A second polarity changing circuit connected to the second capacitor in parallel, including a fourth inductor and a second polarity changing switch connected to the fourth inductor in series and selectively turned on or off;
One end is electrically connected to a plurality of nodes each formed between a low potential end of the battery module, a high potential end of the battery module, and a plurality of battery cells connected in series, and the other end is connected to the second series resonant circuit. Second transmission lines; And
It includes; a plurality of second transmission switches which are respectively installed on the plurality of second transmission lines and selectively turned on or off;
The control unit, the battery stack balancing device, characterized in that for controlling the plurality of second transfer switch and the second polarity change switch.
According to claim 3,
The battery stack balancing device, characterized in that the other end of each second transmission line constituting the plurality of second transmission lines is alternately connected to one end or the other end of the second series resonance circuit.
The method of claim 4,
The control unit, the battery stack balancing device, characterized in that for controlling the plurality of second transfer switches to be zero current switching or zero voltage switching in accordance with the half of the resonant cycle of the second series resonant circuit.
The method of claim 4,
When the second polarity change switch is turned on, the control unit is configured to perform zero current switching or zero voltage switching in accordance with half of the resonant cycle of the second parallel resonance circuit formed by the second capacitor and the fourth inductor. Battery stack balancing device characterized in that it controls the polarity change switch.
The method of claim 4,
The control unit compares the polarity of the voltage of at least one battery cell to which the second series resonant circuit is to be powered with the polarity of the voltage charged in the second capacitor, and the second polarity change switch and the plurality of second. Battery stack balancing device characterized in that it controls the transfer switch.
The method of claim 7,
The control unit turns on the second polarity change switch when the voltage polarity of at least one battery cell to which the second series resonant circuit is to be powered is the same as the voltage polarity of the voltage charged in the second capacitor. Battery stack balancing device, characterized in that to control to turn off all of the second transfer switch.
The method of claim 4,
The control unit compares the polarity of the voltage of at least one battery cell to which the second series resonant circuit will supply power with the polarity of the voltage charged in the second capacitor, and changes the second polarity change switch and the plurality of second transmissions. Battery stack balancing device characterized in that it controls the switch.
The method of claim 9,
The control unit turns off the second polarity change switch when the voltage polarity of at least one battery cell to which the second series resonant circuit supplies power is equal to the polarity of the voltage charged in the second capacitor, and the second polarity change switch is turned off. Controlling the serial resonant circuit to turn on the two second transfer switches connected to both ends of the at least one battery cell to supply power, and turn off the second transfer switches excluding the two second transfer switches. Battery stack balancing device characterized by.
The method of claim 9,
The control unit turns on the second polarity change switch when the voltage polarity of at least one battery cell to which the second series resonant circuit supplies power is different from the polarity of the voltage charged in the second capacitor, and turns on the second polarity change switch. Battery stack balancing device characterized in that the control to turn off all of the two transfer switches.
According to claim 2,
The cell balancing unit, discharge resistance; And a discharge switch connected in series to the discharge resistor.
The control unit, the battery stack balancing device, characterized in that for controlling the discharge switch.
delete According to claim 1,
The control unit, the battery stack balancing device, characterized in that for controlling the plurality of first transmission switches to be zero-current switching or zero-voltage switching in accordance with the half of the resonant cycle of the first series resonant circuit.
According to claim 1,
The control unit is configured to perform zero current switching or zero voltage switching in accordance with half of the resonance cycle of the first parallel resonance circuit formed by the first capacitor and the second inductor when the first polarity change switch is turned on. 1 Battery stack balancing device characterized in that it controls the polarity change switch.
delete According to claim 1,
The control unit turns on the first polarity change switch when the voltage polarity of at least one battery module to which the first series resonant circuit is to receive power and the voltage polarity of the voltage charged in the first capacitor are the same, and the plurality of Battery stack balancing device, characterized in that for controlling to turn off all of the first transmission switch.
According to claim 1,
The controller compares the polarity of the voltage of at least one battery module to which the first series resonant circuit will supply power with the polarity of the voltage charged in the first capacitor, and the first polarity change switch and the plurality of first transmissions. Battery stack balancing device characterized in that it controls the switch.
The method of claim 18,
The control unit turns off the first polarity changing switch when the voltage polarity of at least one battery module to which the first series resonant circuit supplies power is the same as the polarity of the voltage charged in the first capacitor, and the first polarity changing switch is turned off. Controlling the serial resonant circuit to turn on two first transfer switches connected to both ends of the at least one battery module to supply power, and turn off the first transfer switches other than the two first transfer switches. Battery stack balancing device characterized by.
The method of claim 18,
The control unit turns on the first polarity change switch when the voltage polarity of at least one battery module to which the first series resonant circuit supplies power is different from the polarity of the voltage charged in the first capacitor, and turns on the plurality of first Battery stack balancing device, characterized in that the control to turn off all of the transfer switch.
A battery pack comprising the battery stack balancing device according to any one of claims 1 to 12, 14, 15 and 17 to 20.
An electric vehicle comprising the battery stack balancing device according to any one of claims 1 to 12, 14, 15 and 17 to 20.

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