AC power output device

Abstract

An AC power output device according to one embodiment of the present invention is a device that outputs AC power from a plurality of batteries connected in series, and includes: a switching unit connected to each of the plurality of batteries and configured to turn on and off the electrical connection between the corresponding battery and other batteries according to the operating state; a filter unit configured to receive the output voltages of the plurality of batteries as input, adjust the polarity of the output voltages of the plurality of batteries according to the operating state, and output a voltage of the adjusted polarity; and a control unit configured to control the operating state of the switching unit and the filter unit so that AC power is output from the plurality of batteries.

Description

Technical Field

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[0001] This application claims priority based on Korean Patent Application No. 10-2023-0102311 filed on August 4, 2023, and all of the content disclosed in the specification and drawings of that application is incorporated into this application.

[0002] The present invention relates to an AC power output device.

Background Art

[0003] Conventionally, in a battery pack composed of battery cells or modules, an inverter is provided to convert direct current (DC) generated by the battery pack into alternating current (AC) in order to output an AC power supply. For example, the inverter can convert the DC voltage of the battery pack into, for example, three-phase AC voltages of U, V, and W using internal power semiconductors. The thus-converted AC voltage is supplied to an electric vehicle or the like and used as a drive source.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention aims to provide an AC power output device that generates and outputs an AC power supply from batteries connected in series through switch control without using an inverter.

Means for Solving the Problems

[0005] An AC power output device according to one aspect of the present invention is a device that outputs AC power from a plurality of batteries connected in series, and includes: a switching unit connected to each of the plurality of batteries and configured to turn on and off the electrical connection between the corresponding battery and other batteries according to the operating state; a filter unit configured to receive the output voltages of the plurality of batteries as input, adjust the polarity of the output voltages of the plurality of batteries according to the operating state, and output a voltage of the adjusted polarity; and a control unit configured to control the operating state of the switching unit and the filter unit so that AC power is output from the plurality of batteries.

[0006] The control unit may be configured to control the operating state of the switching unit at each preset first cycle to change the number of batteries connected in series.

[0007] Furthermore, the AC power output device may further include a measuring unit configured to measure battery information, including at least one of the voltage, current, and temperature of each of the plurality of batteries.

[0008] The control unit may be configured to determine a priority order for a plurality of batteries based on battery information measured by the measurement unit, and to control the operating state of the corresponding switching unit according to the determined priority order.

[0009] The control unit may be configured to estimate the State of Charge (SOC) of each of the multiple batteries based on the battery information, and to set the priority order higher in descending order of the estimated SOCs.

[0010] The control unit may be configured to estimate the SOC and SOH (State of Health) of each of the multiple batteries based on the battery information, and to set the priority higher in order of the estimated SOH and estimated SOC.

[0011] The control unit may be configured to estimate the SOC and SOH of each of the multiple batteries based on the battery information, set the priority higher in order of the estimated SOH in descending order, and, if the estimated SOHs are the same, set the priority higher in order of the estimated SOC in descending order.

[0012] The control unit may be configured to select a corresponding number of batteries from the plurality of batteries in order of priority for each first cycle, and to control the operating state of the switching unit corresponding to the selected batteries to an energized state so that only the selected batteries are connected in series.

[0013] The control unit may be configured to update the priority order for the plurality of batteries in each of the first cycles.

[0014] The control unit may be configured to control the operating state of the filter unit at pre-set second cycles to reverse the polarity of the output voltage of the battery connected in series.

[0015] The switching unit may be configured to include a first contact configured to be connected to one end of each of the plurality of batteries, a second contact configured to be connected to the other end of the battery, and a third contact configured to be electrically connected to the first contact or the second contact when the switching unit is energized.

[0016] The aforementioned AC power supply may consist of a non-sinusoidal AC power supply.

[0017] A battery pack according to another aspect of the present invention includes an AC power output device according to one aspect of the present invention.

[0018] An automobile according to yet another aspect of the present invention includes an AC power output device according to one aspect of the present invention. [Effects of the Invention]

[0019] According to one aspect of the present invention, an AC power supply can be generated and output through switch control without using an inverter.

[0020] Moreover, according to one aspect of the present invention, since an inverter is not required, the circuit configuration of a battery pack including an AC power supply output device is simplified, and the production cost of the battery pack can be reduced.

[0021] The effects of the present invention are not limited to the above-described effects, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0022] The drawings attached to this specification serve to facilitate a better understanding of the technical idea of the present invention together with the detailed description of the invention to be described later, and the present invention is not to be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0023] [Figure 1] It is a diagram schematically showing an AC power supply output device according to an embodiment of the present invention. [Figure 2] It is a diagram schematically showing an exemplary configuration of an AC power supply output device according to an embodiment of the present invention. [Figure 3] It is a block diagram showing a hardware configuration for realizing a control unit included in an AC power supply output device according to the present invention. [Figure 4] It is a diagram schematically showing an AC power supply according to an embodiment of the present invention. [Figure 5] It is a diagram schematically showing an embodiment of an AC power supply according to an embodiment of the present invention. [Figure 6] In the embodiment of FIG. 5, it is a diagram schematically showing the priority order and SOC of the battery at each time point. [Figure 7] It is a diagram schematically showing an automobile according to another embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0024] The terms and words used in this specification and in the claims are not to be interpreted in a manner limited to their general and dictionary meanings, but rather in a manner corresponding to the technical idea of ​​the present invention, in accordance with the principle that inventors can appropriately define the concepts of terms in order to best describe their invention.

[0025] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that there are various equivalents and modifications that can be substituted for them at the time of filing this application.

[0026] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function would obscure the gist of the present invention, such detailed description will be omitted.

[0027] Terms that include ordinal numbers, such as "1st," "2nd," etc., are used to distinguish one component from others among a variety of components, and these terms do not limit the components themselves.

[0028] When a part of the specification "includes" a certain component, unless otherwise specified, this does not exclude other components, but rather means that it may include other components.

[0029] Furthermore, when a part of the specification is described as being "connected" to another part, this includes not only "direct connections" but also "indirect connections" mediated by other elements.

[0030] Conventionally, when using secondary batteries that primarily generate DC power, a separate component called an inverter is required to output AC power, which increases the cost and size of the battery pack. For example, if the size of the battery pack increases, the size of the inverter also tends to increase, thus reducing the overall energy density of the battery pack. In addition, there is a problem of reduced output efficiency due to losses during the power switching process in the inverter itself.

[0031] This invention was conceived in view of the above circumstances, and provides an AC power output device that can generate and output AC power through switch control without using an inverter, a battery pack including the device, and an electric vehicle.

[0032] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0033] Figure 1 is a schematic diagram showing an AC power output device 100 according to one embodiment of the present invention, and Figure 2 is a schematic diagram showing an exemplary configuration of the AC power output device 100 according to one embodiment of the present invention.

[0034] An AC power output device 100 according to one embodiment of the present invention may be a device that outputs AC power from a plurality of batteries (first battery B1 to fourth battery B4) connected in series. For example, the AC power output device 100 can convert the DC power generated by the plurality of batteries (first battery B1 to fourth battery B4) into AC power and output it without the need for an inverter or other configuration. On the other hand, in this embodiment, four batteries, the first battery B1, the second battery B2, the third battery B3, and the fourth battery B4, are used, but the invention is not limited to this, and various other numbers of batteries can be used in combination depending on the needs and environment.

[0035] Here, each battery (Battery 1 to Battery 4) refers to a single, independent cell equipped with a negative terminal and a positive terminal, and physically separable. As an example, lithium-ion batteries or lithium polymer batteries can be considered as each battery (Battery 1 to Battery 4). In addition, in the AC power output device 100 according to one embodiment of the present invention, the battery may refer to a battery module in which multiple cells are connected in series and / or parallel. For the sake of explanation, in the following, each battery (Battery 1 to Battery 4) will be described as a single independent cell.

[0036] Referring to Figure 1, the AC power output device 100 may include a switching unit 110, a filter unit 120, a control unit 130, a measuring unit 140, and a storage unit 150.

[0037] The switching unit 110 may be configured to be connected to multiple batteries (first battery B1 to fourth battery B4).

[0038] For example, in the embodiment shown in Figure 2, the multiple switching units (first switching unit 111 to fourth switching unit 114) may each be provided to correspond to multiple batteries (first battery B1 to fourth battery B4). The first switching unit 111 may be connected to the first battery B1, and the second switching unit 112 may be connected to the second battery B2. The third switching unit 113 may be connected to the third battery B3, and the fourth switching unit 114 may be connected to the fourth battery B4.

[0039] The switching unit 110 may be configured to turn the electrical connection between a corresponding battery and other batteries on and off (ON / OFF) depending on the operating state.

[0040] In one embodiment, the operating states of the switching unit 110 may include a first energized state, a second energized state, and a de-energized state.

[0041] The non-powered state is a state in which the switching unit 110 is not energized. When the switching unit 110 is in a non-powered state, it may be in an unloaded state.

[0042] The first energized state is when the switching unit 110 is controlled by the control unit 130 and connected to the corresponding battery. When the switching unit 110 is in the first energized state, the corresponding battery is electrically connected to other adjacent batteries.

[0043] The second energized state is a state in which the switching unit 110 is controlled by the control unit 130, but is not connected to the corresponding battery. When the switching unit 110 is in the second energized state, the corresponding battery is not electrically connected to other batteries. For example, when the switching unit 110 is in the second energized state, the corresponding battery is not electrically connected to other adjacent batteries.

[0044] For example, in the embodiment shown in Figure 2, each switching unit (first switching unit 111 to fourth switching unit 114) may include a first contact c1, a second contact c2, and a third contact c3. For example, in the first switching unit 111 of the first battery B1, the first contact c1 may be configured to be connected to one end of the first battery B1, and the second contact c2 to the other end of the first battery B1. Also, the third contact c3 of the first battery B1 may be configured to be connected to the other end of the adjacent second battery B2. With such connections, the third contact c3 of the first battery B1 can be selectively connected to the first contact c1 or the second contact c2 as needed. For example, when the operating state of the first switching unit 111 is the first energized state, the third contact c3 of the first battery B1 is electrically connected to the first contact c1, thereby electrically connecting the first battery B1 to the adjacent second battery B2. Furthermore, the third contact c3 of the first battery B1 may be electrically connected to the second contact c2 when the operating state of the first switching unit 111 is the second energized state, in which case the first battery B1 may be configured to disconnect its electrical connection with the adjacent second battery B2.

[0045] Figure 2 shows an embodiment in which each switching unit (first switching unit 111 to fourth switching unit 114) is located on the negative terminal side of the corresponding battery (first battery B1 to fourth battery B4). However, the connection position of the switching unit 110 is not limited by the embodiment in Figure 2, and each switching unit (first switching unit 111 to fourth switching unit 114) may be located on the positive terminal side of the corresponding battery (first battery B1 to fourth battery B4). In this case, for example, the first contact c1 of each battery may be connected to the positive terminal of the battery, and the second contact c2 may be connected to the negative terminal of the battery. Furthermore, the third contact c3 of each battery may be configured to be selectively electrically connected to the first contact or the second contact when the operating state of the switching unit 110 is energized.

[0046] The filter unit 120 may be configured to receive the output voltage inputs of multiple batteries (first battery B1 to fourth battery B4).

[0047] For example, the filter unit 120 can be connected to the high-current path L of multiple batteries (first battery B1 to fourth battery B4). That is, the DC voltage output from multiple batteries (first battery B1 to fourth battery B4) can be applied to the filter unit 120.

[0048] For example, in the embodiment shown in Figure 2, the filter unit 120 can be connected to the high-current path L of multiple batteries (first battery B1 to fourth battery B4). That is, the DC voltages output from multiple batteries (first battery B1 to fourth battery B4) can be input to the filter unit 120.

[0049] The filter unit 120 may be configured to adjust the polarity of the output voltages of multiple batteries (first battery B1 to fourth battery B4) according to the operating state.

[0050] For example, the filter unit 120 may be configured to reverse the polarity of the output voltages input from multiple batteries B. For example, the filter unit 120 may adjust the polarity of the output voltage to positive (+) or negative (-) depending on the operating state. Alternatively, the filter unit 120 may use separate battery cells for positive voltage and battery cells for negative voltage, or adjust the polarity of the output voltage to positive (+) or negative (-) using a full-bridge or half-bridge system that applies positive and negative voltages in a circuit.

[0051] The control unit 130 may be configured to control the operating states of the switching unit 110 and the filter unit 120 so that AC power is output from multiple batteries (first battery B1 to fourth battery B4).

[0052] The control unit 130 can be connected to a plurality of switching units (first switching unit 111 to fourth switching unit 114) and a filter unit 120 in a manner that enables communication. Furthermore, the control unit 130 can control the operating state of each of the plurality of switching units (first switching unit 111 to fourth switching unit 114) and the operating state of the filter unit 120.

[0053] For example, in the embodiment shown in Figure 2, the control unit 130 can be connected to a plurality of switching units (first switching unit 111 to fourth switching unit 114) and a filter unit 120, respectively.

[0054] In one embodiment, the control unit 130 can control the switching unit 110 to adjust the number of connected batteries among the multiple batteries (first battery B1 to fourth battery B4), and control the filter unit 120 to adjust the polarity of the output voltages of the multiple batteries (first battery B1 to fourth battery B4).

[0055] In one embodiment, the AC power supply may consist of a non-sinusoidal AC power supply. That is, the output voltages of the multiple batteries (first battery B1 to fourth battery B4) are DC voltages, and the polarity of the output voltages is adjusted to AC by the filter unit 120, so the AC power supply output by the AC power supply output device 100 may be a non-sinusoidal AC power supply.

[0056] Figure 3 is a block diagram showing the hardware configuration for realizing the control unit 130 included in the AC power output device 100 according to the present invention.

[0057] In one embodiment, the control unit 130 may include an MCU 132, a memory 134, a communication interface 136, and an input / output interface 138. The MCU 132 is a microcontroller unit, which is a processor that executes various programs stored in the memory 134, processes various data used in such programs, and executes the functions of the control unit 130.

[0058] Memory 134 can store operational data for various programs related to the operation of the lithium secondary battery system for the operation of the control unit 130. Multiple such memories 134 may be provided as needed. Memory 134 may be volatile memory or non-volatile memory. As volatile memory, memory 134 may be RAM (Random Access Memory), DRAM (Dynamic RAM), SRAM (Static RAM), etc. As non-volatile memory, memory 134 may be ROM (Read Only Memory), PROM (Programmable ROM), EAROM (Electrically Alterable ROM), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), flash memory, etc. The above examples of memory 134 are merely illustrative and are not limited to these.

[0059] The communication interface 136 is configured to send and receive various types of data with the server and can be various devices capable of supporting wired or wireless communication. For example, through the communication interface 136, programs for the operation of the control unit 130 and various types of data can be sent and received via wired or wireless connection from an external server separately provided. The input / output interface 138 can provide an interface that connects input devices (not shown), such as a keyboard, mouse, or touch panel, and output devices (not shown), such as a display, with the MCU 132, enabling data transmission and reception.

[0060] Figure 4 is a schematic diagram showing an AC power supply according to one embodiment of the present invention. For example, the embodiment in Figure 4 is a schematic diagram showing the AC power supply output from the battery pack 10 in Figure 2.

[0061] In the embodiment shown in Figure 4, voltages v1, v2, v3, and v4 are the voltages output from one, two, three, and four batteries, respectively. Positive voltages have positive polarity, and negative voltages have negative polarity. Referring to Figures 2 and 4, a non-sinusoidal AC power supply can be output from time t1 using multiple batteries (first battery B1 to fourth battery B4).

[0062] An AC power output device 100 according to one embodiment of the present invention does not have an inverter and can generate and output AC power from multiple batteries (first battery B1 to fourth battery B4). An AC power output device 100 according to one embodiment of the present invention has the advantage of a relatively simple circuit configuration because it does not require an inverter.

[0063] The control unit 130 may be configured to control the operating state of the switching unit 110 at each preset first cycle T1 to change the number of batteries connected in series.

[0064] For example, the control unit 130 can control the operating state of the switching unit 110 for each first cycle T1. Therefore, the number of batteries connected in series can be changed for each first cycle T1.

[0065] In the embodiment shown in Figure 4, assuming that an AC power supply is output from time t1, the number of batteries connected in series can be changed every T1 cycle from time t1. At time t1, one battery may be connected to the filter unit 120. Therefore, a voltage of v1 can be output at time t1. Subsequently, the number of connected batteries can be changed by one each time T1 cycle. For example, at time t2, two batteries are connected and a voltage of v2 is output; at time t3, three batteries are connected and a voltage of v3 is output; at time t4, four batteries are connected and a voltage of v4 is output. Also, at time t5, three batteries are connected again and a voltage of v3 is output; at time t6, two batteries are connected and a voltage of v2 is output; and at time t7, one battery is connected and a voltage of v1 is output.

[0066] The control unit 130 may be configured to control the operating state of the filter unit 120 at pre-set second cycles T2 to reverse the polarity of the output voltage of the batteries connected in series.

[0067] For example, the control unit 130 can control the operating state of the filter unit 120 every second cycle T2. Therefore, the polarity of the battery output voltage can be reversed every second cycle T2.

[0068] In the embodiment shown in Figure 4, the polarity of the output voltage can be reversed every T2 cycles starting from time t1. That is, a positive polarity voltage is output at time t1, and the polarity of the output voltage can be reversed every T2 cycles. For example, at time t8, one battery is connected and a voltage of -v1 is output; at time t9, two batteries are connected and a voltage of -v2 is output; at time t10, three batteries are connected and a voltage of -v3 is output; and at time t11, four batteries are connected and a voltage of -v4 is output. Also, at time t12, three batteries are connected again and a voltage of -v3 is output; at time t13, two batteries are connected and a voltage of -v2 is output; and at time t14, one battery is connected and a voltage of -v1 is output.

[0069] Referring to Figures 2 and 4, an AC power output device 100 according to one embodiment of the present invention can output an AC power supply with a maximum voltage of "v4[V]", a minimum voltage of "-v4[V]", and a period of "2×T2". Thus, the AC power output device 100 according to one embodiment of the present invention can output an AC power supply with the required specifications without the need for an inverter, by adjusting the battery voltage from the stage of generating voltage with the batteries by appropriately adjusting, for example, the number of connected batteries and the period. Furthermore, by selectively connecting batteries used at different times, for example, battery cells used only during peak conditions will have a lower usage frequency, allowing all battery cells to be used uniformly, thus effectively managing the battery life.

[0070] The following describes an embodiment in which the control unit 130 controls the switching unit 110 to determine which of the multiple batteries (first battery B1 to fourth battery B4) are connected in series.

[0071] Referring further to Figure 1, the AC power output device 100 may further include a measuring unit 140.

[0072] The measuring unit 140 may be configured to measure battery information including at least one of the voltage, current, and temperature of each of the multiple batteries (first battery B1 to fourth battery B4).

[0073] For example, the measuring unit 140 can be connected to each of the multiple batteries (first battery B1 to fourth battery B4). The measuring unit 140 can also be configured to measure the voltage and / or temperature of each of the multiple batteries (first battery B1 to fourth battery B4). Furthermore, the measuring unit 140 can be connected to the current path of each of the multiple batteries (first battery B1 to fourth battery B4) to measure the current of each of the multiple batteries (first battery B1 to fourth battery B4).

[0074] In the embodiment shown in Figure 2, the measuring unit 140 can measure the voltages of the first battery B1, the second battery B2, the third battery B3, and the fourth battery B4, respectively.

[0075] The measurement unit 140 can be connected to the control unit 130 via wired and / or wireless communication. The measurement unit 140 can then transmit the measured battery information to the control unit 130.

[0076] The control unit 130 may be configured to estimate the State of Charge (SOC) of each of the multiple batteries (first battery B1 to fourth battery B4) based on the battery information measured by the measurement unit 140.

[0077] For example, the control unit 130 can estimate the SOC based on the voltage information received from the measurement unit 140, based on a profile that is pre-set to show the correspondence between voltage and SOC.

[0078] As another example, the control unit 130 can estimate the SOC based on the voltage and temperature information received from the measurement unit 140, based on a pre-configured profile that shows the correspondence between voltage, temperature, and SOC. That is, the control unit 130 can estimate the SOC of multiple batteries (first battery B1 to fourth battery B4) using a profile in which the SOC corresponding to voltage and temperature is set.

[0079] The control unit 130 may be configured to determine the priority of multiple batteries (first battery B1 to fourth battery B4) based on the estimated SOC.

[0080] In one embodiment, the control unit 130 may be configured to set priorities in order of the estimated SOC, with higher priority given to those with larger SOCs.

[0081] Furthermore, the control unit 130 may be configured to control the operating state of the corresponding switching unit 110 according to the determined priority.

[0082] For example, the control unit 130 preferentially discharges batteries with a larger State of Charge (SOC), and can therefore control the operating state of the corresponding switching unit 110 according to the priority determined for each battery. This allows multiple batteries (first battery B1 to fourth battery B4) to be used uniformly during the process of outputting AC power.

[0083] In other words, with the AC power output device 100, the batteries are discharged according to the priority based on the State of Charge (SOC), so for example, multiple batteries (first battery B1 to fourth battery B4) deteriorate evenly. That is, since there is no deterioration imbalance among the multiple batteries (first battery B1 to fourth battery B4), the expected lifespan of the multiple batteries (first battery B1 to fourth battery B4) can be improved.

[0084] Therefore, the AC power output device 100 according to one embodiment of the present invention can prevent degradation imbalances among multiple batteries B and further prevent capacity loss to multiple batteries B by controlling the switching unit 110 according to the priority based on the State of Charge.

[0085] Figure 5 is a schematic diagram showing one embodiment of an AC power supply according to one embodiment of the present invention.

[0086] Figure 5 shows an embodiment in which AC power is output from time t1 in the battery pack 10 according to the embodiment in Figure 2. For ease of explanation, the negative polarity output voltage is not shown.

[0087] The control unit 130 may be configured to select a corresponding number of batteries from among a plurality of batteries B in order of priority for each first cycle T1.

[0088] In the embodiment shown in Figure 5, the first battery B1 is selected from time t1 to time t2, and the second battery B2 and the third battery B3 may be selected from time t2 to time t3. From time t3 to time t4, the first battery B1, the second battery B2 and the fourth battery B4 are selected, and from time t4 to time t5, the first battery B1, the second battery B2, the third battery B3 and the fourth battery B4 may be selected. From time t5 to time t6, the first battery B1, the third battery B3 and the fourth battery B4 are selected, and from time t6 to time t7, the second battery B2 and the third battery B3 may be selected. From time t7 to time t8, the fourth battery B4 may be selected.

[0089] Furthermore, the control unit 130 may be configured to control the operating state of the switching unit 110 corresponding to the selected battery to a first energized state so that only the selected battery is connected in series.

[0090] For example, in the embodiment shown in Figure 5, the first battery B1 can be discharged from time t1 to time t2. Therefore, the control unit 130 can control the first switching unit 111 to a first energized state from time t1 to time t2, and control the second switching unit 112, the third switching unit 113, and the fourth switching unit 114 to a second energized state.

[0091] From time t2 to time t3, the second battery B2 and the third battery B3 are connected in series and can be discharged. Therefore, the control unit 130 can control the second switching unit 112 and the third switching unit 113 to the first energized state and the first switching unit 111 and the fourth switching unit 114 to the second energized state from time t2 to time t3.

[0092] From time t3 to time t4, the first battery B1, the second battery B2, and the fourth battery B4 can be connected in series and discharged. Therefore, the control unit 130 can control the first switching unit 111, the second switching unit 112, and the fourth switching unit 114 to the first energized state and the third switching unit 113 to the second energized state from time t3 to time t4.

[0093] From time t4 to time t5, the first battery B1, the second battery B2, the third battery B3, and the fourth battery B4 can be connected in series and discharged. Therefore, the control unit 130 can control the first switching unit 111, the second switching unit 112, the third switching unit 113, and the fourth switching unit 114 to the first energized state from time t4 to time t5.

[0094] From time t5 to time t6, the first battery B1, the third battery B3, and the fourth battery B4 can be connected in series and discharged. Therefore, the control unit 130 can control the first switching unit 111, the third switching unit 113, and the fourth switching unit 114 to the first energized state and the second switching unit 112 to the second energized state from time t5 to time t6.

[0095] From time t6 to time t7, the second battery B2 and the third battery B3 are connected in series and can be discharged. Therefore, the control unit 130 can control the second switching unit 112 and the third switching unit 113 to the first energized state and the first switching unit 111 and the fourth switching unit 114 to the second energized state from time t6 to time t7.

[0096] From time t7 to time t8, the fourth battery B4 may be discharged. Therefore, the control unit 130 may control the fourth switching unit 114 to the first energized state from time t7 to time t8, and control the first switching unit 111, the second switching unit 112, and the third switching unit 113 to the second energized state.

[0097] On the other hand, the control unit 130 may be configured to update the priority order for multiple batteries B at each first cycle T1.

[0098] For example, if the priority order for multiple batteries (first battery B1 to fourth battery B4) is not updated, there is a risk of degradation imbalance among the multiple batteries (first battery B1 to fourth battery B4). Therefore, the control unit 130 may update the priority order at each first cycle T1 in order to prevent degradation imbalance among the multiple batteries (first battery B1 to fourth battery B4). Here, the control unit 130 may estimate the State of Charge (SOC) of the multiple batteries (first battery B1 to fourth battery B4) at each first cycle T1 and update the priority order of the multiple batteries (first battery B1 to fourth battery B4) based on the estimated SOC.

[0099] Figure 6 is a schematic diagram showing the battery priority and SOC at each time point in the embodiment of Figure 5. In the embodiment of Figure 6, it is assumed that the initial SOCs of the first battery B1, second battery B2, third battery B3, and fourth battery B4 are equal to 100%, and that the SOC of the battery being discharged decreases by 10% with each cycle T1. For the sake of explanation, it is assumed that if the SOCs of two or more batteries are equal, the battery with the lower reference number will be given a higher priority.

[0100] Referring to Figure 6, the control unit 130 can adjust the number of batteries connected in series for each first cycle T1 to output AC power. In this process, differences may occur in the state of charge (SOC) of the multiple batteries (first battery B1 to fourth battery B4), so the control unit 130 can update the priority order based on the SOC of the multiple batteries (first battery B1 to fourth battery B4) for each first cycle T1. Then, the control unit 130 can select the batteries to be connected in series for the next cycle according to the updated priority order. In one embodiment, the control unit 130 can select the batteries to be connected in series for the next cycle in order of the highest updated priority order.

[0101] In the embodiment shown in Figure 6, the priority is updated every first cycle T1, so that the State of Charge (SOC) of the first battery B1, second battery B2, third battery B3, and fourth battery B4 at time t8 becomes equal to 60%. Therefore, unbalanced degradation of multiple batteries (first battery B1 to fourth battery B4) can be prevented through the updating of the priority. Subsequently, from time t8 onwards, the polarity of the output voltage is reversed by the filter unit 120, and a negative polarity AC power supply is output.

[0102] On the other hand, the control unit 130 can estimate the State of Charge (SOC) and State of Health (SOH) of each of the multiple batteries (first battery B1 to fourth battery B4) based on the battery information.

[0103] For example, the control unit 130 can estimate the State of Charge (SOC) and State of Health (SOH) of each of the multiple batteries (first battery B1 to fourth battery B4) based on the battery information received from the measurement unit 140. Here, the method by which the control unit 130 estimates the SOH of the multiple batteries (first battery B1 to fourth battery B4) based on the battery information received from the measurement unit 140 may be, for example, a conventional SOH estimation method.

[0104] The control unit 130 can set the priority order for each of the multiple batteries (first battery B1 to fourth battery B4) by considering the State of Charge (SOC) and State of Health (SOH) of each battery. For example, the control unit 130 can set the priority order higher in order of the estimated SOH and estimated SOC.

[0105] On the other hand, the control unit 130 can set the priority of the batteries in order of the estimated SOH to the largest. Among the multiple batteries (first battery B1 to fourth battery B4), batteries with the same estimated SOH can be given higher priority in order of the estimated SOC.

[0106] In other words, the control unit 130 estimates the State of Charge (SOC) and State of Health (SOH) of each of the multiple batteries (first battery B1 to fourth battery B4) based on the battery information, and can set a higher priority for each battery in descending order of its estimated SOH. Furthermore, if the estimated SOH is the same for some of the multiple batteries (first battery B1 to fourth battery B4), the control unit 130 can set a higher priority for each battery in descending order of its estimated SOC.

[0107] For example, the control unit 130 may set the priority order of multiple batteries (first battery B1 to fourth battery B4) by considering the first estimated SOH and the second estimated SOC. Depending on one embodiment, among the multiple batteries (first battery B1 to fourth battery B4), batteries with the same estimated SOH and estimated SOC may be given a higher priority order with the battery having the lower reference number. The control unit 130 may then be configured to control the operating state of the corresponding switching unit 110 according to the determined priority order.

[0108] Furthermore, the control unit 130 may be configured to update the priority order based on the SOC and SOH of the multiple batteries (first battery B1 to fourth battery B4) for each first cycle T1. Similar to the embodiment described above, in order to prevent the multiple batteries (first battery B1 to fourth battery B4) from degrading unevenly, the control unit 130 may estimate the SOC and SOH of the multiple batteries (first battery B1 to fourth battery B4) for each first cycle T1. Then, based on the estimated SOC and estimated SOH, the control unit 130 may update the priority order of the multiple batteries (first battery B1 to fourth battery B4) for each first cycle T1.

[0109] The AC power output device 100 can prevent the multiple batteries (first battery B1 to fourth battery B4) from degrading unevenly during the process of outputting AC power by updating the priority order while considering the SOC and SOH of the multiple batteries (first battery B1 to fourth battery B4).

[0110] Furthermore, the AC power output device 100 may further include a storage unit 150. The storage unit 150 may store data or programs necessary for each component of the AC power output device 100 to operate and function, or data generated during the process of operation and functioning. The type of storage unit 150 is not particularly limited, as long as it is a known information recording means known to be able to record, erase, update, and read data. For example, information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. The storage unit 150 may also store program code that defines the processes that can be executed by the control unit 130.

[0111] For example, the memory unit 150 may store the voltages of multiple batteries (first battery B1 to fourth battery B4) measured by the measurement unit 140. The memory unit 150 may also store the State of Charge (SOC) of multiple batteries (first battery B1 to fourth battery B4) estimated by the control unit 130. Furthermore, the memory unit 150 may store the State of Health (SOH) of multiple batteries (first battery B1 to fourth battery B4) estimated by the control unit 130. Finally, the memory unit 150 may store the priority order for multiple batteries (first battery B1 to fourth battery B4) determined by the control unit 130.

[0112] The AC power output device 100 according to the present invention can be applied to a battery management system (BMS). That is, the BMS according to the present invention may include the AC power output device 100 described above. In such a configuration, at least some of the components of the AC power output device 100 can be realized by complementing or adding to the functions of components included in a conventional BMS. For example, the switching unit 110, filter unit 120, control unit 130, measurement unit 140, and storage unit 150 of the AC power output device 100 can be realized as components of a BMS.

[0113] Furthermore, the AC power output device 100 according to the present invention may be provided in the battery pack 10. That is, the battery pack 10 according to the present invention may include the above-described AC power output device 100 and one or more batteries. The battery pack 10 may further include electrical components (relays, fuses, etc.) and a case, etc.

[0114] Referring to Figure 2, a battery pack 10 according to one embodiment of the present invention may include a plurality of batteries (first battery B1 to fourth battery B4) and an AC power output device 100. The battery pack 10 can output AC power through the AC power output device 100 without the need for a separate inverter.

[0115] Figure 7 is a schematic diagram showing an automobile 700 according to another embodiment of the present invention.

[0116] An AC power output device 100 according to one embodiment of the present invention can be installed in an automobile 700 such as an electric vehicle (EV) or a hybrid vehicle (HV).

[0117] For example, in the embodiment shown in Figure 7, the automobile 700 may include a battery pack 710 and an AC power output device 100. Depending on one embodiment, the AC power output device 100 may be included in the battery pack 710. The AC power output through the AC power output device 100 can be applied to the motor of the automobile 700.

[0118] In other words, by applying AC power to the motor of the automobile 700 through the AC power output device 100, the automobile 700 can be driven.

[0119] As described above, the present invention has been explained with limited embodiments and drawings, but it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical idea and claims of the present invention by persons with ordinary skill in the art to which the present invention pertains.

[0120] Furthermore, the present invention described above can be substituted, modified, and altered in various ways by a person with ordinary skill in the art to which the present invention pertains, without departing from the technical spirit of the invention, and is not limited by the embodiments described above and the accompanying drawings. For diverse modifications, all or part of each embodiment can be selectively combined to form the present invention. [Explanation of Symbols]

[0121] 10: Battery Pack 100: AC power output device 110: Switching section 120: Filter section 130: Control Unit 140: Measuring part 150: Storage section

Claims

1. An AC power output device that outputs AC power from multiple batteries connected in series, A switching unit connected to each of the multiple batteries and configured to turn on and off the electrical connection between the corresponding battery and other batteries according to the operating state, A filter unit configured to receive the output voltages of multiple batteries, adjust the polarity of the output voltages of the multiple batteries according to their operating state, and output a voltage with the adjusted polarity, AC power output device including a control unit configured to control the operating state of the switching unit and the filter unit so that AC power is output from multiple batteries.

2. The control unit, The AC power output device according to claim 1, configured to change the number of batteries connected in series by controlling the operating state of the switching unit at each preset first cycle.

3. The system further includes a measuring unit configured to measure battery information, including at least one of the voltage, current, and temperature of each of the multiple batteries, The control unit, The AC power output device according to claim 2, configured to determine a priority order for a plurality of batteries based on battery information measured by the measurement unit, and to control the operating state of the corresponding switching unit according to the determined priority order.

4. The control unit, The AC power output device according to claim 3, which is configured to estimate the state of charge (SOC) of each of the multiple batteries based on the battery information, and to set the priority order higher in order of the estimated SOC.

5. The control unit, The AC power output device according to claim 3, which is configured to estimate the SOC and SOH (health status) of each of the multiple batteries based on the battery information, and to set the priority order higher in order of the estimated SOH and estimated SOC.

6. The control unit, Based on the aforementioned battery information, the SOC and SOH of each of the multiple batteries are estimated, and the priority is set higher in order of the estimated SOH, The AC power output device according to claim 3, wherein, if the estimated SOHs are equal, the priority is set higher in order of the estimated SOC in descending order.

7. The control unit, The AC power output device according to claim 3, configured to select a corresponding number of batteries from a plurality of batteries in order of priority for each first cycle, and to control the operating state of the switching unit corresponding to the selected batteries to an energized state so that only the selected batteries are connected in series.

8. The control unit, The AC power output device according to claim 3, configured to update the priority order for a plurality of batteries each first cycle.

9. The control unit, The AC power output device according to claim 2, configured to control the operating state of the filter unit at pre-set second cycles to reverse the polarity of the output voltage of the battery connected in series.

10. The switching unit is A first contact configured to be connected to one end of the battery, A second contact configured to be connected to the other end of the aforementioned battery, The AC power output device according to claim 1, further comprising a third contact configured to be electrically connected to the first contact or the second contact when the operating state of the switching unit is energized.

11. The AC power output device according to claim 1, wherein the AC power supply is composed of a non-sinusoidal AC power supply.

12. A battery pack including an AC power output device according to any one of claims 1 to 11.

13. An automobile comprising an AC power output device according to any one of claims 1 to 11.

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