Device and method for controlling battery

Abstract

A device for controlling a battery, according to an embodiment of the present invention, controls a battery pack including a plurality of modules, each module including a plurality of cells connected in series, and may include: a selection circuit unit including one or more switches connected to a positive electrode of each cell and one or more switches connected to a negative electrode of each cell; a resonance circuit unit including one or more inductors and one or more capacitors and having one end connected to a first node and the other end connected to a second node; and a control unit that controls the plurality of switches in the selection circuit unit and one or more switches in the resonance circuit unit to measure the impedance of a selected cell among the plurality of cells or to perform charge equalization between the plurality of cells or charge equalization between the plurality of modules.

Description

Battery control device and method

[0001] This application claims the benefit of Korean Patent Application No. 10-2024-0118296 filed with the Korean Intellectual Property Office on September 2, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery control device and method, and more particularly, to a battery control device and method including a circuit capable of simultaneously performing charge equalization and battery impedance measurement.

[0003] Secondary batteries, which can be recharged and reused after use, are manufactured into battery modules or packs by connecting multiple battery cells in series, depending on the output capacity required by the device. These batteries serve as power sources for various devices. These batteries are used in a wide range of applications, from small, high-tech electronic devices like smartphones to electric bicycles, electric vehicles, and even energy storage systems (ESS).

[0004] A battery pack is a structure composed of multiple battery cells. If any of the cells experience overvoltage, overcurrent, or overheating, this can compromise the safety and operational efficiency of the battery pack. Therefore, a means of detecting these issues is essential. Therefore, battery packs are equipped with a Battery Management System (BMS), which measures the voltage of each battery cell and monitors and controls the voltage status of the cells based on these measurements.

[0005] Meanwhile, the performance of the multiple battery cells that make up a battery pack can vary for various reasons, resulting in voltage imbalances between the cells. If a battery pack is used with a voltage imbalance between cells, its performance becomes dependent on the degraded cells, limiting the overall performance of the pack. In other words, cell imbalance reduces the available capacity / power of the battery.

[0006] In addition, battery cells with degraded performance have the characteristic of further accelerating performance degradation, that is, cell aging, so if degraded battery cells are left unattended, the lifespan of the battery pack will also rapidly decrease.

[0007] To solve this cell imbalance problem, passive balancing was used, which selectively connects resistors to both ends of the battery cell to discharge the battery cell, or active balancing was used, which transfers power from a battery cell with a high voltage to a battery cell with a low voltage through a capacitor.

[0008] Meanwhile, measuring and analyzing battery impedance is a frequently used method for assessing the degree of battery deterioration or abnormality. To measure battery impedance, a circuit is typically added to measure the impedance of each cell, obtaining the necessary measurements and then calculating the impedance using the measurements.

[0009] In this way, equalization and impedance measurement to resolve cell imbalance were previously performed using separate devices or circuits.

[0010] As a related prior art document, there is Korean Patent Publication No. 10-2016-0064089.

[0011] An object of the present invention to solve the above problems is to provide a battery control device including a control circuit capable of simultaneously performing cell-to-cell / module charge equalization and battery impedance measurement.

[0012] Another object of the present invention to solve the above problems is to provide a battery pack including the battery control device.

[0013] According to one embodiment of the present invention for achieving the above object, a battery control device is provided, which controls a battery pack including a plurality of modules, each module including a plurality of cells connected in series, the device including: a selection circuit including at least one switch connected to a positive pole of each cell and at least one switch connected to a negative pole of each cell; a resonance circuit including at least one inductor and at least one capacitor, the resonance circuit having one end connected to a first node and the other end connected to a second node; and a control unit controlling the plurality of switches in the selection circuit and the one or more switches in the resonance circuit to measure impedance for a cell selected from among the plurality of cells or to perform charge equalization among the plurality of cells or charge equalization among the plurality of modules.

[0014] The above resonant circuit may include a first inductor; and a first capacitor connected in series with the first inductor.

[0015] The battery control device may further include a second inductor and an inductor connection switch connected in parallel with the first inductor; and a second capacitor and a capacitor connection switch connected in parallel with the first capacitor.

[0016] Here, the resonant frequency provided by the resonant circuit changes depending on the ON / OFF of the inductor connection switch and the capacitor connection switch.

[0017] In addition, the battery control device may further include a voltage meter for measuring a voltage between the first node and the second node; and a current meter for measuring a current flowing in the resonant circuit.

[0018] At this time, the control unit can turn on a switch connected to the positive pole of the cell to be measured for impedance and a switch connected to the negative pole, and calculate the impedance of the cell based on the voltage obtained from the voltage measuring device and the current obtained from the current measuring device.

[0019] The battery control device may further include a polarity reversal switch having one end connected to the first node and the other end connected to the second node.

[0020] Meanwhile, the control unit can control the turning on of the positive connection switch and the negative connection switch of the first cell to accumulate energy in the capacitor within the resonant circuit, and then control the turning off of the positive connection switch and the negative connection switch of the first cell and control the turning on of the positive connection switch and the negative connection switch of the second cell, thereby transferring energy from the first cell to the second cell.

[0021] Here, when the first cell and the second cell are, in the order of the serial connection structure of the cells, one is an odd cell and the other is an even cell, before controlling the turning on of the positive connection switch and the negative connection switch of the second cell, the polarity reversal switch is turned on to reverse the polarity of the capacitor in the resonant circuit, and then the positive connection switch and the negative connection switch of the second cell are controlled to be turned on, so that the energy stored in the capacitor can be transferred to the second cell.

[0022] In addition, when the first cell and the second cell are both odd cells or both even cells in the order of the serial connection structure of the cells, the energy stored in the capacitor can be transferred to the second cell, and then the polarity reversal switch can be turned on to reverse the polarity of the capacitor in the resonant circuit.

[0023] At this time, the control unit can control the inductor connection switch and the capacitor connection switch to be turned OFF when performing cell-to-cell charge equalization from the first cell to the second cell.

[0024] Meanwhile, the resonant circuit includes an inductor connected to the first node and a capacitor connected to the second node, and the resonant circuit can be arranged in each module.

[0025] The above battery control device further includes one or more resonant circuit connection switch units that connect resonant circuit units located within each module, wherein each resonant circuit connection switch unit may be configured as a pair of resonant circuit connection switches connected to one end and the other end of a capacitor of the resonant circuit unit within each module.

[0026] The control unit turns on a switch connected to the positive electrode of a first cell among the series-connected cells in the first module and a switch connected to the negative electrode of a last cell among the series-connected cells, turns on one or more resonant circuit connection switch units in the battery pack, accumulates energy in a capacitor in the plurality of resonant circuit units, and then turns off the connection switches of the first module and turns on a switch connected to the positive electrode of a first cell among the series-connected cells in the second module and a switch connected to the negative electrode of a last cell among the series-connected cells in the second module, thereby performing charge equalization between the first module and the second module.

[0027] In addition, the control unit can turn on a switch connected to the positive pole of the cell to be measured for impedance and a switch connected to the negative pole, measure a current flowing through the resonant circuit and a voltage between the first node and the second node, and calculate the impedance of the target cell based on the measured current and voltage.

[0028] At this time, the resonant frequency may vary depending on the ON / OFF state of one or more resonant circuit connection switch units.

[0029]

[0030] According to another embodiment of the present invention, a battery pack includes a plurality of modules, each module including a plurality of cells connected in series; a selection circuit including at least one switch connected to a positive electrode of each cell and at least one switch connected to a negative electrode of each cell; and a resonance circuit including at least one inductor and at least one capacitor, one end of which is connected to the first node and the other end of which is connected to the second node, wherein the battery pack may include a control unit that controls the plurality of switches in the selection circuit and the one or more switches in the resonance circuit to measure impedance for a cell selected from among the plurality of cells or to perform charge equalization among the plurality of cells or charge equalization among the plurality of modules.

[0031] According to the battery control device according to one embodiment of the present invention as described above, cell-to-cell charge equalization and battery impedance measurement are possible simultaneously.

[0032] According to a battery control device according to another embodiment of the present invention, charge equalization between modules and battery impedance measurement are possible simultaneously.

[0033] Additionally, impedance can be measured in various resonant frequency environments, enabling more accurate battery diagnosis.

[0034] Figure 1 shows an example of a battery structure to which the present invention can be applied.

[0035] Figure 2 shows a circuit diagram of a battery control device according to one embodiment of the present invention.

[0036] Figure 3 shows the current flowing in the resonant circuit according to an embodiment of the present invention.

[0037] FIG. 4 is a drawing exemplarily showing a path formed by a selected cell and a resonant circuit when measuring impedance using a battery control device according to an embodiment of the present invention.

[0038] FIG. 5 illustrates a first example of an operation sequence for performing cell-to-cell equalization using a battery control device according to an embodiment of the present invention.

[0039] FIG. 6 illustrates a second example of an operation sequence for performing cell-to-cell equalization using a battery control device according to an embodiment of the present invention.

[0040] Figure 7 shows a circuit diagram of a battery control device according to another embodiment of the present invention.

[0041] FIGS. 8A and 8B illustrate an example of an operation sequence for performing inter-module equalization using a battery control device according to an embodiment of the present invention.

[0042] 100: Battery pack

[0043] 200: BMS

[0044] 210: Control Unit

[0045] 220, 720: Selection circuit

[0046] 230, 730: Resonant circuit

[0047] 770: Resonant circuit connection switch section

[0048] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0049] Terms such as "first," "second," "A," and "B" may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the "second component," and similarly, the second component could also be referred to as the "first component." The term "and / or" includes any combination of multiple related items listed or any one of multiple related items listed.

[0050] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0051] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0052] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0053]

[0054] Some terms used in this specification are defined as follows:

[0055] A battery cell is the smallest unit that stores electricity, and a module contains multiple cells connected in series.

[0056] A battery pack is an assembly of multiple battery cells electrically connected, and can be configured by connecting multiple modules in series or parallel.

[0057]

[0058] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

[0059]

[0060] Figure 1 shows an example of a battery structure to which the present invention can be applied.

[0061] In FIG. 1, the battery pack (100) may be configured to include a plurality of battery cells. A plurality of battery cells may be connected in series to form a module, and a battery pack may be configured to include a plurality of modules. The most commonly used battery cells are lithium-ion (Li-Ion) battery cells. The battery pack may be connected to a load through positive and negative terminals and may perform charge / discharge operations. Each of these battery packs may be equipped with a battery management system (BMS).

[0062] The pack BMS (200) monitors the current, voltage, and temperature of each battery pack it manages, calculates the SOC (State of Charge) based on the monitoring results, and controls charging and discharging. Here, the SOC is the current charged state of the battery expressed as a percentage [%].

[0063] To perform such operations, the BMS (200) may include various components such as a fuse, a current sensing element, a thermistor, a switch, and a balancer. The BMS (200) mostly includes an MCU (Micro Controller Unit) (201) or a BMIC (Battery Monitoring Integrated Chip) for interfacing with and controlling these. Here, the BMIC may be an IC-type component located inside the BMS and measuring information such as voltage, temperature, and current of a battery cell / module. The BMS (200) may also include a memory (202) that stores at least one command performed by the MCU and various data generated during the BMS operation.

[0064] Additionally, the BMS monitors battery cells, reads cell voltages, and relays these data to other systems connected to the battery. To this end, the BMS may include a communication module (not shown) for communicating with other systems within the device, including the battery system. The BMS's communication module can communicate with other systems within the device using the Controller Area Network (CAN). In this case, components, modules, or systems within the BMS can be interconnected via the CAN bus.

[0065] The battery control device according to the embodiment of the present invention described hereinafter may be included in a pack BMS and implemented as a part of the pack BMS.

[0066]

[0067] Figure 2 shows a circuit diagram of a battery control device according to one embodiment of the present invention.

[0068] The battery control device according to an embodiment of the present invention may be applied to a battery structure in which a plurality of modules are included in a battery pack, and a plurality of cells are electrically connected in series within each module. For example, as illustrated in FIG. 2, the module (110) may have a form in which a plurality of cells are connected in series.

[0069] A battery control device according to an embodiment of the present invention is a device for controlling a battery pack including a plurality of modules, each including a plurality of cells connected in series, and may be largely configured to include a control unit (210), a selection circuit unit (220), and a resonance circuit unit (230). The control unit (210) controls a plurality of switches in the selection circuit unit and one or more switches in the resonance circuit unit to measure impedance of one of the plurality of cells or perform charge equalization between the plurality of cells or charge equalization between the plurality of modules.

[0070] In particular, the embodiment of FIG. 2 describes a battery control device that measures impedance for one of a plurality of cells or performs charge equalization between the plurality of cells.

[0071] More specifically, in FIG. 2, the control unit (210) generates switch control signals for the switches (W1, W2, W3, W4, W5) in the selection circuit unit (220) and the switches (W7, W8) in the resonant circuit unit (230) and transmits them to the corresponding circuits. In addition, the control unit (210) receives the voltage value measured by the voltage meter (280) and the current value measured by the current meter (290) to calculate the impedance value for the selected cell.

[0072] In addition, the selection circuit (220) includes at least one switch connected to the anode of each cell and at least one switch connected to the cathode of each cell. For example, in FIG. 2, the selection circuit (220) includes five switches (W1, W2, W3, W4, W5) connected to the anodes and cathodes of four cells. The anode of the first cell is connected to the first switch, and the cathode of the first cell is connected to the second switch. The second switch is simultaneously connected to the anode of the second cell. The cathode of the second cell is connected to the third switch, and the third switch is simultaneously connected to the anode of the third cell. In summary, the switches connected to the anodes of the plurality of cells connected in series are cross-connected to the first node or the second node. That is, the first switch connected to the positive pole of the first cell, the third switch connected to the positive pole of the third cell, have one end connected to the first node, and the second switch connected to the positive pole of the second cell, and the fourth switch connected to the positive pole of the fourth cell have one end connected to the second node. In other words, the switches connected to the negative poles of multiple cells connected in series can be described as being connected to the second node or the first node in an intersection.

[0073] Meanwhile, the switches (W1, W2, W3, W4, W5) included in the selection circuit unit (220) can be implemented with various switching elements, and according to one embodiment, the switches can be implemented with MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The switches (W1, W2, W3, W4, W5) can be selectively turned on or off according to a control signal of the control unit (210).

[0074] In addition, the resonant circuit (230) has a form in which one or more inductors and one or more capacitors are connected in series through one or more switches, and one end of the resonant circuit (230) is connected to a first node and the other end of the resonant circuit (230) is connected to a second node.

[0075] Here, the resonant circuit may include: a first inductor; a first capacitor connected in series with the first inductor; a second inductor and an inductor connection switch connected in parallel with the first inductor; and a second capacitor and a capacitor connection switch connected in parallel with the first capacitor.

[0076] More specifically, referring to FIG. 2, the resonant circuit section (230) includes an inductance section (L1, L2) and a capacitance section (C1, C2), and the inductance section and the capacitance section are connected in series.

[0077] The inductance section (L1, L2) has a form in which a first inductor (L1) and a second inductor (L2) are connected in parallel. The second inductor (L2) can form part of the inductance section together with the first inductor (L1) by turning on the inductor connection switch (W7). On the other hand, when the inductor connection switch (W7) is turned off, the second inductor (L2) is excluded from the inductance section. In other words, the inductance value of the inductance section can be adjusted according to the on / off control of the inductor connection switch.

[0078] The capacitance section (C1, C2) has a form in which a first capacitor (C1) and a second capacitor (C2) are connected in parallel. The second capacitor (C2) can form part of the capacitance section together with the first capacitor (C1) by turning on the capacitor connection switch (W8). On the other hand, when the capacitor connection switch (W8) is turned off, the second capacitor (C2) is excluded from the capacitance section. In other words, the capacitance value of the capacitance section can be adjusted according to the on / off control of the capacitor connection switch.

[0079] In other words, the resonant frequency provided by the resonant circuit (230) may vary depending on the ON / OFF of the inductor connection switch (W7) and the capacitor connection switch (W8).

[0080] Meanwhile, the battery control device according to the present embodiment may further include a voltage measuring device (280) for measuring the voltage between the first node and the second node, and a current measuring device (290) for measuring the current flowing in the resonant circuit. The control unit may turn on a switch connected to the positive pole of the cell to be impedance measured and a switch connected to the negative pole, and may calculate the impedance of the corresponding cell based on the voltage obtained from the voltage measuring device and the current obtained from the current measuring device.

[0081] In addition, when a battery pack is configured by including a plurality of modules as illustrated in FIG. 2, the control unit (210) according to the embodiment of FIG. 2 may be implemented by being placed in each module. In addition, the battery pack may be implemented in a manner in which only one control unit (210) is placed in the battery pack to control the circuits within each module.

[0082]

[0083] Figure 3 shows the current flowing in the resonant circuit and the cell voltage according to an embodiment of the present invention.

[0084] The graph at the top of Fig. 3 represents the resonant current flowing through the resonant circuit (230) of Fig. 2. The resonant current is an AC (Alternating Current) current flowing through a path connecting the cell selected by the control unit, the first inductor, and the first capacitor. In other words, the resonant current may be a current flowing through the selected cell.

[0085] In addition, the graph at the bottom of Fig. 3 is a graph showing the measured voltage between the first node and the second node in the circuit of Fig. 2. If a cell is selected by the control of the switch in the selection circuit, either the first node or the second node can be connected to the positive pole of the corresponding cell, and the remaining node can be connected to the negative pole of the corresponding cell. Therefore, the voltage between the first node and the second node is equal to the voltage of the corresponding cell.

[0086] Therefore, the control unit can calculate the impedance of the selected cell from the magnitude and phase difference of the AC components of the measured current and voltage.

[0087]

[0088] FIG. 4 is a drawing exemplarily showing a path formed by a selected cell and a resonant circuit when measuring impedance using a battery control device according to an embodiment of the present invention.

[0089] Fig. 4 illustrates the electrical flow formed when the fourth switch (W4) and the fifth switch (W5) are turned on to measure the impedance of the fourth cell among the four cells in the module. If both the inductor connection switch (W7) and the capacitor connection switch (W8) in the resonant circuit are turned off, the current flow is as illustrated in Fig. 4.

[0090] Meanwhile, the resonant frequency provided by the resonant circuit unit (230) changes depending on the ON / OFF of the inductor connection switch (W7) and the capacitor connection switch (W8). The number of cases depending on the ON / OFF of the inductor connection switch (W7) and the capacitor connection switch (W8) is four as shown in FIG. 4. Accordingly, the resonant frequency that can be provided by the resonant circuit unit according to the embodiment of FIG. 4 may be four in total. Accordingly, the control unit can adjust the resonant frequency by changing the connection status of the inductor connection switch (W7) and the capacitor connection switch (W8), and can measure the impedance at different frequencies.

[0091]

[0092] Returning to FIG. 2, the control unit (210) can perform charge equalization between multiple cells by controlling multiple switches within the selection circuit and one or more switches within the resonance circuit. To this end, the battery control device according to the embodiment of the present invention may further include a polarity reversal switch (250) having one end connected to a first node and the other end connected to a second node. Here, the polarity reversal switch (250) is a switch for changing the polarity of the resonance capacitor (C1).

[0093] More specifically, the control unit controls the turning on of the positive connection switch and the negative connection switch of the first cell to accumulate energy in the capacitor within the resonant circuit, and then controls the turning off of the positive connection switch and the negative connection switch of the first cell and controls the turning on of the positive connection switch and the negative connection switch of the second cell, thereby performing charge equalization between the first cell and the second cell.

[0094] According to one embodiment, when the first cell and the second cell are, in the order of the serial connection structure of the cells, one is an odd cell and the other is an even cell, before controlling the turning on of the positive connection switch and the negative connection switch of the second cell, the polarity reversal switch is turned on to reverse the polarity of the capacitor in the resonant circuit, and then the positive connection switch and the negative connection switch of the second cell are controlled to be turned on, so that energy stored in the capacitor can be transferred to the second cell.

[0095] According to another embodiment, when the first cell and the second cell are both odd cells or both even cells in the order of the cell connection structure, the energy stored in the capacitor can be transferred to the second cell, and then the polarity reversal switch can be turned on to reverse the polarity of the capacitor in the resonant circuit.

[0096]

[0097] FIG. 5 illustrates a first example of an operation sequence for performing cell-to-cell equalization using a battery control device according to an embodiment of the present invention.

[0098] The example in Fig. 5 shows the sequence of cell-to-cell equalization operations when energy is transferred from the first cell to the fourth cell.

[0099] More specifically, the control unit turns on the positive connection switch and the negative connection switch of the first cell to accumulate energy in the capacitor (C1) within the resonant circuit (step 1 of FIG. 5), then turns off the positive connection switch and the negative connection switch of the first cell and turns on the positive connection switch and the negative connection switch of the fourth cell (step 3 of FIG. 5), thereby performing inter-cell charge equalization from the first cell to the fourth cell.

[0100] At this time, since the first cell is an odd cell and the fourth cell is an even cell in the order of the serial connection structure of the cells, before controlling the turning on of the positive connection switch and the negative connection switch of the fourth cell, the polarity inversion switch (W6) is turned on to invert the polarity of the capacitor (C1) in the resonant circuit (step 2 of FIG. 5), and then the positive connection switch and the negative connection switch of the fourth cell are controlled to be turned on, so that the energy stored in the capacitor is transferred to the fourth cell (step 3 of FIG. 5). Here, when energy is accumulated in the capacitor (C1) in the resonant circuit, the voltage of the first node becomes higher than that of the second node, and in order to transfer energy to the fourth cell, the voltage of the second node must be higher than that of the first node. Therefore, before transferring energy to the fourth cell, the polarity of the resonant capacitor is inverted through the polarity inversion switch.

[0101] Thereafter, the control unit can repeatedly perform steps 1 to 3 described above, and the number of repetitions can be determined by considering the voltage difference between cells requiring energy transfer, the accumulable capacity of the resonant capacitor, etc.

[0102] Meanwhile, while the inter-cell charge equalization is performed, the control unit can control the inductor connection switch (W7) and the capacitor connection switch (W8) in the resonant circuit to be turned ON or OFF. The impedance of the resonant circuit can be changed according to the ON / OFF states of the inductor connection switch (W7) and the capacitor connection switch (W8), thereby controlling the equalization current. Although there is an advantage in that equalization is performed faster as the equalization current increases, there is a disadvantage in that the energy consumed in the circuit increases, so that the impedance can be appropriately adjusted and used by controlling the inductor connection switch and the capacitor connection switch depending on the situation.

[0103]

[0104] FIG. 6 illustrates a second example of an operation sequence for performing cell-to-cell equalization using a battery control device according to an embodiment of the present invention.

[0105] The example in Fig. 6 shows the sequence of cell-to-cell equalization operations when energy is transferred from the second cell to the fourth cell.

[0106] More specifically, the control unit turns on the positive connection switch and the negative connection switch of the second cell to accumulate energy in the capacitor within the resonant circuit (step 1 of FIG. 6), then turns off the positive connection switch and the negative connection switch of the second cell and turns on the positive connection switch and the negative connection switch of the fourth cell (step 2 of FIG. 6), thereby performing charge equalization between the second cell and the fourth cell.

[0107] In addition, since the second cell and the fourth cell are both even cells in the order of the serial connection structure of the cells, after the energy stored in the capacitor (C1) is transferred to the fourth cell, the polarity reversal switch (W6) is turned on (step 3 of FIG. 6) to reverse the polarity of the capacitor (C1) in the resonant circuit. In this embodiment, the procedure for reversing the polarity of the resonant capacitor through the polarity reversal switch is to more efficiently transfer energy through polarity reversal of the resonant capacitor that accumulates energy. More specifically, the size of the resonant current is proportional to the difference between the cell voltage and the initial voltage of the resonant capacitor, and if charging and discharging are repeated in the same direction, the voltage of the resonant capacitor converges to the same level as the cell voltage, which causes a problem in that the size of the resonant current continues to decrease. In this embodiment, this problem can be solved by turning on the polarity reversal switch to reverse the polarity of the resonant capacitor.

[0108] Thereafter, the control unit can repeatedly perform steps 1 to 3 described above, and the number of repetitions can be determined by considering the voltage difference between cells requiring energy transfer, the accumulable capacity of the resonant capacitor, etc.

[0109] Meanwhile, while the inter-cell charge equalization is performed, the control unit can control the inductor connection switch (W7) and the capacitor connection switch (W8) in the resonant circuit to be turned ON or OFF. The impedance of the resonant circuit can be changed according to the ON / OFF states of the inductor connection switch (W7) and the capacitor connection switch (W8), thereby controlling the equalization current. Although there is an advantage in that equalization is performed faster as the equalization current increases, there is a disadvantage in that the energy consumed in the circuit increases, so that the impedance can be appropriately adjusted and used by controlling the inductor connection switch and the capacitor connection switch depending on the situation.

[0110]

[0111] Figure 7 shows a circuit diagram of a battery control device according to another embodiment of the present invention.

[0112] A battery control device according to an embodiment of the present invention may be applied to a battery structure in which a plurality of modules are included in a battery pack, and a plurality of cells are electrically connected in series within a single module. Here, the plurality of modules (module 1, module 2, module 3) within the same pack may be implemented in a series-connected form, as illustrated in FIG. 7.

[0113] A battery control device according to an embodiment of the present invention is a device for controlling a battery pack including a module (110) including a plurality of cells connected in series, and may be largely configured to include a control unit (not shown), a selection circuit unit (720), and a resonance circuit unit (730). The control unit controls a plurality of switches in the selection circuit unit and one or more switches in the resonance circuit unit to measure impedance of one of the plurality of cells or perform charge equalization between the plurality of cells or charge equalization between the plurality of modules.

[0114] In particular, the embodiment of FIG. 7 describes a battery control device that measures impedance for one of a plurality of cells or performs charge equalization between a plurality of modules.

[0115] In the example of Fig. 7, the battery pack includes a plurality of modules, each module having five cells connected in series.

[0116] More specifically, the selection circuit (720) includes at least one switch connected to the positive pole of each cell and at least one switch connected to the negative pole of each cell. For example, the selection circuit (720) of module 1 in FIG. 7 includes six switches (W9, W10, W11, W12, W13, W33) connected to the positive poles and negative poles of five cells. The selection circuit (720) according to the embodiment of FIG. 7, similarly to the embodiment of FIG. 2, the switches connected to the positive poles of each cell are cross-connected to the first node or the second node. That is, the switch connected to the positive pole of the first cell, the switch connected to the positive pole of the third cell, and the switch connected to the positive pole of the fifth cell have their other ends connected to the second node, and the switch connected to the positive pole of the second cell and the switch connected to the positive pole of the fourth cell have their other ends connected to the first node.

[0117] Meanwhile, the switches (W9, W10, W11, W12, W13, W33) included in the selection circuit unit (720) can be implemented with various switching elements, and according to one embodiment, the switches can be implemented with MOSFETs. The switches (W9, W10, W11, W12, W13, W33) can be selectively turned on or off according to a control signal of a control unit (not shown).

[0118] In addition, resonant circuit parts (730-1, 730-2, 730-3) are arranged for each module, and in this embodiment, the resonant circuit parts may include an inductor connected to the first node and a capacitor connected to the second node. The battery control device may further include polarity reversal switches (W14, W21, W31) located between the contact point of the first node and the inductor and the contact point of the second node and the capacitor. At this time, the resonant circuit parts (730-1, 730-2, 730-3) and the polarity reversal switches may perform the same role as the role of the resonant circuit parts and the polarity reversal switches included in the embodiment illustrated in FIG. 2. In this embodiment, the polarity reversal switch is for more efficiently transferring energy through polarity reversal of a resonant capacitor that accumulates energy. More specifically, the magnitude of the resonant current is proportional to the difference between the cell voltage and the initial voltage of the resonant capacitor. However, if charging and discharging are repeated in the same direction, the voltage of the resonant capacitor converges to the same level as the cell voltage, resulting in a problem in which the magnitude of the resonant current continues to decrease. In the present embodiment, this problem can be solved by turning on the polarity reversal switch to reverse the polarity of the resonant capacitor.

[0119] Meanwhile, the battery control device may further include one or more resonant circuit connection switch units (770-1, 770-2) that connect the resonant circuit unit of the module to the resonant circuit unit of another neighboring module. Each resonant circuit connection switch unit may be composed of a pair of resonant circuit connection switches (W15 and W30; W23 and W24) connected to one end and the other end of the capacitor of the resonant circuit unit in each module. The number of resonant circuit connection switch units may be set to (the number of modules included in the battery pack - 1).

[0120] In the embodiment of FIG. 7, for example, the resonant circuit unit (730-1) of module 1 and the resonant circuit unit (730-2) of module 2 can be connected by turning on the first resonant circuit connection switch unit (770-1). In addition, the resonant circuit unit (730-1) of module 1 and the resonant circuit unit (730-2) of module 3 can be connected by turning on the first resonant circuit connection switch unit (770-1) and the second resonant circuit connection switch unit (770-2).

[0121] The control unit of the battery control device can turn on a switch connected to the positive pole of a cell to be impedance measured and a switch connected to the negative pole, measure a current flowing through a resonant circuit and a voltage between the first node and the second node, and calculate the impedance of the target cell based on the measured current and voltage. At this time, the control unit can set the resonant frequency differently by controlling the ON / OFF of one or more resonant circuit connection switch units. Accordingly, the impedance for various resonant frequencies can be measured.

[0122] Meanwhile, the battery control device according to the present embodiment may further include a voltage meter (not shown) for measuring the voltage between the first node and the second node, and a current meter (not shown) for measuring the current flowing through the resonant circuit. At this time, the positions of the voltage meter and the current meter may be set to the same positions as in the embodiment illustrated in FIG. 2.

[0123] Accordingly, the control unit can turn on a switch connected to the positive pole and a switch connected to the negative pole of the cell to be impedance measured, and calculate the impedance of the cell based on the voltage obtained from the voltage meter and the current obtained from the current meter.

[0124] Additionally, the battery control device can perform charge equalization between the first module and the second module using a circuit as illustrated in FIG. 7.

[0125] More specifically, the battery control device turns on a switch connected to the positive pole of a first cell among the series-connected cells in the first module and a switch connected to the negative pole of a last cell among the series-connected cells, and turns on one or more resonant circuit connection switch units within the battery pack, thereby accumulating energy in capacitors within a plurality of resonant circuit units.

[0126] The battery control device can then transfer energy from the first module to the second module by controlling the connection switches of the first module to be turned off and the switch connected to the positive pole of the first cell among the series-connected cells in the second module to be turned on and the switch connected to the negative pole of the last cell among the series-connected cells.

[0127] Meanwhile, as illustrated in FIG. 7, when a battery pack is configured by including a plurality of modules, one control unit (not shown) may be placed within the battery pack to control the circuit within each module.

[0128] In this case, the battery pack may include a plurality of modules, each module including a plurality of cells connected in series; a selection circuit including at least one switch connected to the positive pole of each cell and at least one switch connected to the negative pole of each cell; and a resonant circuit including at least one inductor and at least one capacitor, one end of which is connected to the first node and the other end of which is connected to the second node.

[0129] At this time, the battery pack may include a control unit that controls a plurality of switches in the selection circuit unit and one or more switches in the resonance circuit unit to measure impedance for a cell selected from among the plurality of cells or perform charge equalization between the plurality of cells or charge equalization between the plurality of modules.

[0130]

[0131] FIGS. 8A and 8B illustrate an example of an operation sequence for performing inter-module equalization using a battery control device according to an embodiment of the present invention.

[0132] Figures 8a and 8b illustrate the flow of current step by step when energy is to be transferred from module 1 to module 3, i.e., in the charge equalization operation between modules 1 and 3.

[0133] In Fig. 8a, the flow of current is illustrated in a state in which energy is being stored in a plurality of resonant capacitors (C3, C4, C5) in a plurality of modules by turning on the switch 33 and the switch 13 of module 1 and controlling the turning on of a plurality of switches (W15, W30, W23, W24) in the first resonant circuit connection switch section and the second resonant circuit connection switch section in the battery pack. In Fig. 8b, it can be confirmed that the energy stored in the plurality of resonant capacitors (C3, C4, C5) is transferred to module 3 by controlling the turning off of the switch 33 and the switch 13 and turning on the switch 32 and the switch 29 of module 3.

[0134] Meanwhile, in a case different from the case illustrated in FIGS. 8a and 8b, even when energy is to be transferred from module 1 to module 2, the first resonant circuit connection switch unit (W15, W30) and the second resonant circuit connection switch unit (W23, W24) can both be turned on to store energy in three resonant capacitors (C3, C4, C5), and then the switches (W20, W22) of module 2 can be turned on to transfer the accumulated energy to module 2. Through this method, rapid equalization can be expected by setting the resonant capacitance as large as possible to increase the resonant current.

[0135]

[0136] The operations of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes any type of recording device that stores data readable by a computer system. Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable program or code to be stored and executed in a distributed manner.

[0137] Additionally, the computer-readable recording medium may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0138] While some aspects of the present invention have been described in the context of a device, they may also represent a description of a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described as a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most significant method steps may be performed by such a device.

[0139] Although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A device for controlling a battery pack including a plurality of modules, each module including a plurality of cells connected in series, A selection circuit comprising at least one switch connected to the positive pole of each cell and at least one switch connected to the negative pole of each cell; A resonant circuit comprising one or more inductors and one or more capacitors, one end of which is connected to a first node and the other end of which is connected to a second node; and A battery control device comprising a control unit that controls a plurality of switches in the selection circuit unit and one or more switches in the resonance circuit unit to measure impedance for a selected cell among the plurality of cells or to perform charge equalization between the plurality of cells or charge equalization between the plurality of modules.

2. In claim 1, The above resonant circuit part, first inductor; and A battery control device comprising a first capacitor connected in series with the first inductor.

3. In claim 2, A second inductor and an inductor connection switch connected in parallel with the first inductor; and A battery control device further comprising a second capacitor and a capacitor connection switch connected in parallel with the first capacitor.

4. In claim 3, A battery control device in which the resonant frequency provided by the resonant circuit changes depending on the ON / OFF of the inductor connection switch and the capacitor connection switch.

5. In claim 1, a voltage meter measuring the voltage between the first node and the second node; and A battery control device further comprising a current measuring device for measuring the current flowing in the resonant circuit.

6. In claim 5, The above control unit, A battery control device that turns on a switch connected to the positive pole of a cell to be measured for impedance and a switch connected to the negative pole, and calculates the impedance of the cell based on the voltage obtained from the voltage meter and the current obtained from the current meter.

7. In claim 1, A battery control device further comprising a polarity reversal switch having one end connected to the first node and the other end connected to the second node.

8. In claim 7, The above control unit, By controlling the turning on of the positive connection switch and the negative connection switch of the first cell, energy is accumulated in the capacitor within the resonant circuit section, By controlling the positive connection switch and the negative connection switch of the first cell to be turned off and controlling the positive connection switch and the negative connection switch of the second cell to be turned on, A battery control device that transfers energy from the first cell to the second cell.

9. In claim 8, If the first cell and the second cell are, in the order of the serial connection structure of the cells, one is an odd cell and the other is an even cell, A battery control device that turns on the polarity reversal switch to reverse the polarity of the capacitor in the resonant circuit before controlling the turning on of the positive connection switch and the negative connection switch of the second cell, and then controls the turning on of the positive connection switch and the negative connection switch of the second cell to transfer energy stored in the capacitor to the second cell.

10. In claim 8, If the first cell and the second cell are both odd cells or both even cells in the order of the serial connection structure of the cells, After transferring the energy stored in the capacitor to the second cell, A battery control device that reverses the polarity of a capacitor in the resonant circuit by turning on the polarity reversal switch.

11. In claim 3, The above control unit, When performing cell-to-cell charge equalization from the first cell to the second cell, A battery control device that controls the above inductor connection switch and the above capacitor connection switch to be turned OFF.

12. In claim 1, The above resonant circuit part, an inductor connected to the first node; and including a capacitor connected to the second node, The above resonant circuit unit is a battery control device arranged in each module.

13. In claim 12, Further comprising one or more resonant circuit connection switch sections connecting the resonant circuit sections located within each module, A battery control device, wherein each resonant circuit connection switch section is composed of a pair of resonant circuit connection switches connected to one end and the other end of a capacitor of the resonant circuit section within each module.

14. In claim 13, The above control unit, A switch connected to the positive pole of the first cell among the series-connected cells in the first module and a switch connected to the negative pole of the last cell among the series-connected cells are turned on, and at least one resonant circuit connection switch section in the battery pack is turned on to store energy in a capacitor in the plurality of resonant circuit sections. Controlling the turn-off of the connection switches of the above first module, By controlling the turning on of a switch connected to the positive pole of the first cell among the series-connected cells in the second module and a switch connected to the negative pole of the last cell among the series-connected cells in the second module, A battery control device that performs charge equalization between the first module and the second module.

15. In claim 13, The above control unit, A battery control device that turns on a switch connected to the positive pole of a cell to be measured for impedance and a switch connected to the negative pole, measures a current flowing through the resonant circuit and a voltage between the first node and the second node, and calculates the impedance of the target cell based on the measured current and voltage.

16. In claim 15, A battery control device whose resonant frequency changes depending on the ON / OFF state of one or more resonant circuit connection switch units.

17. A battery pack comprising a plurality of modules, Each module, Multiple cells connected in series; a selection circuit comprising at least one switch connected to the positive pole of each cell and at least one switch connected to the negative pole of each cell; and A resonant circuit comprising one or more inductors and one or more capacitors, one end of which is connected to a first node and the other end of which is connected to a second node, The above battery pack, A battery pack comprising a control unit that controls a plurality of switches in the selection circuit unit and one or more switches in the resonance circuit unit to measure impedance for a selected cell among the plurality of cells or to perform charge equalization between the plurality of cells or charge equalization between the plurality of modules.

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