Energy storage device, battery charge state sensor, energy storage converter and energy storage system

Abstract

The embodiment of the invention discloses an energy storage device, a battery state-of-charge sensor, an energy storage converter and an energy storage system, relates to a power electronic technology, and solves the problem of how to accurately calculate the SOC of a battery under the condition that a special platform area exists in the corresponding relation between the end voltage of the battery and the SOC. At least one first output end of the controller is connected with the input end of at least one first driving circuit, the two output ends of each first driving circuit are connected with the two ends of one third coil, and the output ends of the multiple magnetic sensors are connected with the multiple first input ends of the controller. The second output end of the controller is connected with the first controlled end of the energy charging and releasing circuit, the input and output end of the energy charging and releasing circuit is connected with the first end of the second coil, the second end of the second coil is connected with the first end of the energy storage element, and the second end of the energy storage element is used for being connected with the grounding end. And the controller is used for calculating the state of charge of the battery according to the voltage variation of the energy storage element.

Description

Technical Field

[0001] The present application relates to power electronics technology, and particularly to an energy storage device, a state of charge sensor for a battery, an energy storage converter, and an energy storage system. Background Art

[0002] The state of charge (SOC) is used to represent the ratio of the remaining capacity of a battery to the capacity in a fully charged state after the battery has been used for a period of time or left idle for a long time, and is usually expressed as a percentage. The value range of SOC is 0 to 1. When SOC is 0, it means the battery is in a fully discharged state, and when SOC is 1, it means the battery is fully charged. The above battery can be a single battery cell, or can be a battery pack. Among them, the battery pack can include multiple battery cells, and the multiple battery cells can be connected in series, parallel or in a mixed connection manner.

[0003] In most cases, there is a clear correspondence between the terminal voltage of a battery and the SOC. By measuring the terminal voltage of the battery, the SOC of the battery can be calculated.

[0004] However, for some batteries, such as lithium iron phosphate (chemical formula LiFePO4, which can be abbreviated as LFP) batteries, there is a special plateau region in the correspondence between the terminal voltage and the SOC. In this plateau region, the change of the terminal voltage of the battery with the SOC is relatively weak, and the SOC cannot be accurately calculated based on the terminal voltage of the battery. Therefore, in the case where there is a special plateau region in the correspondence between the terminal voltage of the battery and the SOC, how to accurately calculate the SOC of the battery has become a technical problem to be solved urgently. Summary of the Invention

[0005] The embodiments of the present application provide an energy storage device, a state of charge sensor for a battery, an energy storage converter, and an energy storage system, which solve the problem of how to accurately calculate the SOC of a battery in the case where there is a special plateau region in the correspondence between the terminal voltage of the battery and the SOC.

[0006] To achieve the above object, the embodiments of the present application adopt the following technical solutions:

[0007] In the first aspect of the embodiment of the present application, an energy storage device is provided. The energy storage device includes a battery and a state of charge sensor for the battery. The state of charge sensor for the battery includes a controller, a charging and discharging circuit, an energy storage element, a first magnetic core, at least one first driving circuit, and a first coil, a second coil, at least one third coil and a plurality of magnetic sensors coupled to the first magnetic core. There is a linear correspondence between the terminal voltage and the state of charge of the energy storage element. One end of the first coil is connected to the positive electrode of the battery, and the other end of the first coil is used to connect to the positive polarity terminal of the load, or one end of the first coil is connected to the negative electrode of the battery, and the other end of the first coil is used to connect to the negative polarity terminal of the load. At least one first output terminal of the controller is respectively connected to the input terminals of at least one first driving circuit. Two output terminals of each first driving circuit are connected to both ends of a third coil. Output terminals of the plurality of magnetic sensors are respectively connected to a plurality of first input terminals of the controller. A second output terminal of the controller is connected to a first controlled terminal of the charging and discharging circuit. The input and output terminals of the charging and discharging circuit are connected to the first end of the second coil. The second end of the second coil is connected to the first end of the energy storage element. The second end of the energy storage element is used to connect to the ground terminal. The charging and discharging circuit is used to charge or discharge the second coil. The controller is used to calculate the state of charge of the battery according to the voltage change amount of the energy storage element.

[0008] Based on this solution, there is a linear correspondence between the terminal voltage and the state of charge of the energy storage element. In the case where there is a special flat region in the correspondence between the terminal voltage and the state of charge of the battery, through a plurality of magnetic sensors, a first switching tube and a second switching tube, the ampere-turns of the first coil can be accurately made equal to the ampere-turns of the second coil, so as to accurately make the change amount of the electric charge of the battery and the change amount of the electric charge of the energy storage element be in a fixed ratio. Thus, the state of charge of the battery can be accurately and highly precisely calculated by detecting the voltage change amount of the energy storage element within a preset time.

[0009] In combination with the first aspect, in one embodiment, the controller is configured to separately send respective corresponding first AC excitation signals to at least one first drive circuit. The controller is further configured to control the charge and discharge circuit to discharge the second coil when the effective value of the voltage across the magnetic sensor is less than or equal to a first voltage threshold, and the induced current in the magnetic sensor has an unsaturated characteristic at the positive peak of the corresponding first AC excitation signal and a saturated characteristic at the negative peak of the corresponding first AC excitation signal. The controller is further configured to control the charge and discharge circuit to charge the second coil when the effective value of the voltage across the magnetic sensor is less than or equal to a first voltage threshold, and the induced current in the magnetic sensor has a saturated characteristic at the positive peak of the corresponding first AC excitation signal and an unsaturated characteristic at the negative peak of the corresponding first AC excitation signal. The controller is further configured to control the charge and discharge circuit to stop discharging or charging the second coil when the effective value of the voltage across the magnetic sensor is greater than the first voltage threshold after controlling the charge and discharge circuit to discharge the second coil, or after controlling the charge and discharge circuit to charge the second coil. The controller is further configured to detect the voltage change amount of the energy storage element within a preset time and calculate the state of charge of the battery when the effective value of the voltage across each of the multiple magnetic sensors is greater than its respective corresponding first voltage threshold.

[0010] Based on this solution, there is a linear correspondence between the terminal voltage of the energy storage element and the state of charge. When there is a special platform region in the correspondence between the terminal voltage of the battery and the state of charge, the ampere-turns of the first coil can be accurately made equal to the ampere-turns of the second coil through multiple magnetic sensors, the first switch tube, and the second switch tube, so as to accurately make the change amount of the electric charge of the battery and the change amount of the electric charge of the energy storage element be in a fixed ratio. Thus, the state of charge of the battery can be accurately and highly precisely calculated by detecting the voltage change amount of the energy storage element within a preset time.

[0011] In combination with the first aspect, in one embodiment, the charge and discharge circuit includes a first switch tube, a second switch tube, and multiple switches, as well as a first inductor and multiple second inductors connected in series. The third output terminal of the controller is connected to the second controlled terminal of the charge and discharge circuit, the controlled terminal of the first switch tube is connected to the first controlled terminal of the charge and discharge circuit, the controlled terminal of the second switch tube is connected to the second controlled terminal of the charge and discharge circuit, the first terminal of the first switch tube is used to receive a positive reference voltage, the first terminal of the second switch tube is used to receive a negative reference voltage, the second terminal of the first switch tube and the second terminal of the second switch tube are connected, the first inductor and the multiple second inductors are connected between the second terminal of the first switch tube and the input-output terminal of the charge and discharge circuit, and the multiple switches are respectively connected in parallel with the multiple second inductors.

[0012] Based on this solution, by controlling the number of turned-on switches, the charging or discharging speed of the second coil can be controlled, the adjustment speed of the ampere-turns of the second coil can be achieved in multiple gears, and the adaptability and detection efficiency of the battery state of charge sensor can be improved.

[0013] Combined with the first aspect, in an embodiment, the charging and discharging circuit further includes a first operational amplifier. The non-inverting input terminal of the first operational amplifier is connected to the first controlled terminal of the charging and discharging circuit, the inverting input terminal of the first operational amplifier is connected to the second controlled terminal of the charging and discharging circuit, the positive power supply terminal of the first operational amplifier is used to receive a positive reference voltage, the negative power supply terminal of the first operational amplifier is used to receive a negative reference voltage, and the output terminal of the first operational amplifier is connected to the controlled terminals of the first switching tube and the second switching tube. The first switching tube is an NPN transistor, an NMOS, or a NIGBT. The second switching tube is a PNP transistor, a PMOS, or a PIGBT. The controlled terminals of the first switching tube and the second switching tube are both bases or gates, the first ends of the first switching tube and the second switching tube are both collectors or drains, and the second ends of the first switching tube and the second switching tube are both emitters or sources.

[0014] Based on this solution, the first operational amplifier drives the first switching tube and the second switching tube simultaneously, eliminating the need to set up two driving circuits to drive the first switching tube and the second switching tube respectively, thereby reducing the circuit complexity and cost.

[0015] Combined with the first aspect, in an embodiment, the first magnetic core includes multiple sub-magnetic cores, at least one first driving circuit includes multiple first driving circuits, at least one third coil includes multiple third coils, the multiple third coils are respectively wound around the multiple sub-magnetic cores, multiple magnetic sensors are respectively coupled to the multiple sub-magnetic cores, and the first coil and the second coil are both wound around the multiple sub-magnetic cores in sequence. When the multiple sub-magnetic cores are saturated respectively, the absolute value of the difference between the ampere-turns of the first coil and the ampere-turns of the second coil in the multiple sub-magnetic cores increases sequentially.

[0016] Based on this solution, the battery state of charge sensor has multiple ranges, and these multiple ranges have the same measurement accuracy, so it can be used to calculate the state of charge of batteries with different rated capacities, and the measurement accuracy is the same. The battery state of charge sensor has high versatility and reliability.

[0017] In combination with the first aspect, in one embodiment, the first magnetic core includes a first magnetic column and a plurality of second magnetic columns arranged in sequence. At least one first driving circuit includes one first driving circuit, and at least one third coil includes one third coil. The first coil, the second coil, and the third coil are all wound around the first magnetic column, and a plurality of magnetic sensors are respectively coupled to the plurality of second magnetic columns. Along the direction away from the first magnetic column, when the plurality of second magnetic columns are saturated respectively, the absolute value of the difference between the ampere-turns of the corresponding first coil and the ampere-turns of the second coil increases sequentially.

[0018] Based on this solution, the state of charge sensor of the battery has multiple ranges, and these multiple ranges have the same measurement accuracy. Thus, it can be used to calculate the state of charge of batteries with different rated capacities, and the measurement accuracy is the same. The versatility and reliability of this state of charge sensor of the battery are relatively high.

[0019] In combination with the first aspect, in one embodiment, the state of charge sensor of the battery further includes a second driving circuit, a second magnetic core, a fourth coil, and a fifth coil, as well as a capacitor and a resistor connected in series. The second magnetic core is coupled to the first magnetic core, and the material of the second magnetic core is the same as that of the first magnetic core. The fourth coil and the fifth coil are coupled to the second magnetic core. The fourth output terminal of the controller is connected to the input terminal of the second driving circuit. The two output terminals of the second driving circuit are connected to the two ends of the fourth coil. The capacitor and the resistor are connected between the two ends of the fifth coil.

[0020] Based on this solution, the material of the second magnetic core is the same as that of the first magnetic core. Through the temperature drift compensation circuit composed of the second driving circuit, the second magnetic core, the fourth coil, the fifth coil, the capacitor, and the resistor, when the temperature affects the saturation magnetic flux and magnetic permeability of the first magnetic column and the plurality of second magnetic columns in the first magnetic core, the saturation magnetic flux and magnetic permeability of the first magnetic core can be made stable again, thereby improving the detection accuracy of the state of charge of the battery.

[0021] The controller is configured to send a second AC excitation signal to the second drive circuit, and the peak-to-valley value of the second AC excitation signal is less than or equal to the peak-to-valley value threshold. The controller is further configured to, after sending the second AC excitation signal to the second drive circuit, when the total harmonic distortion of the current in the fifth coil based on the frequency of the second AC excitation signal as the fundamental wave is greater than the total harmonic distortion threshold, send a third AC excitation signal to the second drive circuit, where the peak-to-valley value of the third AC excitation signal is equal to the peak-to-valley value of the second AC excitation signal, and the frequency of the third AC excitation signal is equal to the resonant frequency of the capacitor and the fifth coil. The controller is further configured to gradually increase the peak-to-valley value of the third AC excitation signal after sending the third AC excitation signal to the second drive circuit. The controller is further configured to stop increasing the peak-to-valley value of the third AC excitation signal and send a fourth AC excitation signal to the first drive circuit when the effective value of the voltage across the fifth coil is less than or equal to the second voltage threshold, and the peak-to-valley value of the fourth AC excitation signal is equal to the increased peak-to-valley value of the third AC excitation signal.

[0022] Based on this solution, the second magnetic core has the same material as the first magnetic core. Through the temperature drift compensation circuit composed of the second drive circuit, the second magnetic core, the fourth coil, the fifth coil, the capacitor and the resistor, when the temperature affects the saturation magnetic flux and magnetic permeability of the first magnetic column and the plurality of second magnetic columns in the first magnetic core, the saturation magnetic flux and magnetic permeability of the first magnetic core can be stabilized again, thereby improving the detection accuracy of the state of charge of the battery.

[0023] Combined with the first aspect, in an implementation, the controller is further configured to send the second AC excitation signal to the second drive circuit after sending the fourth AC excitation signal to the first drive circuit and after a preset time threshold.

[0024] Based on this solution, compensating the saturation magnetic flux and magnetic permeability of the first magnetic column and the plurality of second magnetic columns in the first magnetic core periodically can ensure the detection accuracy of the state of charge of the battery at different times and different temperatures.

[0025] Combined with the first aspect, in an implementation, the state of charge sensor of the battery further includes a current sensor, one end of the current sensor is connected to the second end of the energy storage element, the other end of the current sensor is used to be connected to the ground terminal, and the output terminal of the current sensor is connected to the second input terminal of the controller.

[0026] Based on this solution, by detecting the current flowing through the second coil and the energy storage element with the current sensor, when the controller calculates the state of charge of the battery, it can correct the calculation result according to this current, which can further improve the accuracy of the state of charge calculation of the battery.

[0027] In combination with the first aspect, in one embodiment, the state of charge sensor of the battery further includes a current sensor and a second operational amplifier. One end of the current sensor is connected to the second end of the second coil, the other end of the current sensor is used to be connected to the ground terminal, the output end of the current sensor is connected to the input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the first end of the energy storage element.

[0028] Based on this solution, the current flowing through the second coil is shunted by the current sensor, and the shunted current charges or discharges the energy storage element after passing through the second operational amplifier. The ratio between the change in the charge amount of the battery and the change in the charge amount of the energy storage element, in addition to the turns ratio of the first coil and the second coil, increases the amplification factor of the second operational amplifier. Thus, the ratio multiple between the change in the charge amount of the battery and the change in the charge amount of the energy storage element is larger, a smaller-capacity energy storage element can be used, the volume of the state of charge sensor of the battery can be reduced, and the cost of the state of charge sensor of the battery can be lowered.

[0029] In the second aspect of the embodiments of the present application, a state of charge sensor of a battery is provided. The state of charge sensor of the battery includes a controller, a charge / discharge circuit, an energy storage element, a first magnetic core, at least one first driving circuit, and a first coil, a second coil, at least one third coil and a plurality of magnetic sensors coupled to the first magnetic core. There is a linear correspondence between the terminal voltage of the energy storage element and the state of charge. The first coil is used to be connected between the positive electrode of the battery and the positive-polarity terminal of the load, or the first coil is used to be connected between the negative electrode of the battery and the negative-polarity terminal of the load. At least one first output end of the controller is respectively connected to the input ends of at least one first driving circuit, two output ends of each first driving circuit are connected to both ends of a third coil, the output ends of the plurality of magnetic sensors are respectively connected to a plurality of first input ends of the controller, a second output end of the controller is connected to a first controlled end of the charge / discharge circuit, the input-output end of the charge / discharge circuit is connected to the first end of the second coil, the second end of the second coil is connected to the first end of the energy storage element, the second end of the energy storage element is used to be connected to the ground terminal, and the charge / discharge circuit is used to charge or discharge the second coil. The controller is used to calculate the state of charge of the battery according to the change amount of the voltage of the energy storage element.

[0030] In combination with the second aspect, in one embodiment, the controller is configured to separately send respective corresponding first AC excitation signals to at least one first drive circuit. The controller is further configured to control the charge and discharge circuit to discharge the second coil when the effective value of the voltage across the magnetic sensor is less than or equal to the first voltage threshold, and the induced current in the magnetic sensor has an unsaturated characteristic at the positive peak value of the corresponding first AC excitation signal and a saturated characteristic at the negative peak value of the corresponding first AC excitation signal. The controller is further configured to control the charge and discharge circuit to charge the second coil when the effective value of the voltage across the magnetic sensor is less than or equal to the first voltage threshold, and the induced current in the magnetic sensor has a saturated characteristic at the positive peak value of the corresponding first AC excitation signal and an unsaturated characteristic at the negative peak value of the corresponding first AC excitation signal. The controller is further configured to control the charge and discharge circuit to stop discharging or charging the second coil when the effective value of the voltage across the magnetic sensor is greater than the first voltage threshold after controlling the charge and discharge circuit to discharge the second coil, or after controlling the charge and discharge circuit to charge the second coil. The controller is further configured to detect the voltage change amount of the energy storage element within a preset time and calculate the state of charge of the battery when the effective value of the voltage across each magnetic sensor in a plurality of magnetic sensors is greater than its respective corresponding first voltage threshold.

[0031] In combination with the second aspect, in one embodiment, the charge and discharge circuit includes a first switching tube, a second switching tube and a plurality of switches, and a first inductor and a plurality of second inductors connected in series. The third output terminal of the controller is connected to the second controlled terminal of the charge and discharge circuit, the controlled terminal of the first switching tube is connected to the first controlled terminal of the charge and discharge circuit, the controlled terminal of the second switching tube is connected to the second controlled terminal of the charge and discharge circuit, the first terminal of the first switching tube is configured to receive a positive reference voltage, the first terminal of the second switching tube is configured to receive a negative reference voltage, the second terminal of the first switching tube and the second terminal of the second switching tube are connected, the first inductor and the plurality of second inductors are connected between the second terminal of the first switching tube and the input / output terminal of the charge and discharge circuit, and the plurality of switches are respectively connected in parallel with the plurality of second inductors.

[0032] In combination with the second aspect, in one embodiment, the first magnetic core includes a plurality of sub-magnetic cores, at least one first drive circuit includes a plurality of first drive circuits, at least one third coil includes a plurality of third coils, the plurality of third coils are respectively wound around the plurality of sub-magnetic cores, the plurality of magnetic sensors are respectively coupled to the plurality of sub-magnetic cores, and the first coil and the second coil are both wound around the plurality of sub-magnetic cores in sequence. When the plurality of sub-magnetic cores are respectively saturated, the absolute value of the difference between the ampere-turns of the first coil and the second coil in the plurality of sub-magnetic cores increases in sequence.

[0033] In combination with the second aspect, in one embodiment, the first magnetic core includes a first magnetic column and a plurality of second magnetic columns arranged in sequence, at least one first driving circuit includes one first driving circuit, and at least one third coil includes one third coil. The first coil, the second coil, and the third coil are all wound around the first magnetic column, and a plurality of magnetic sensors are respectively coupled to the plurality of second magnetic columns. Along the direction away from the first magnetic column, when the plurality of second magnetic columns are respectively saturated, the absolute value of the difference between the ampere-turns of the corresponding first coil and the ampere-turns of the second coil increases sequentially.

[0034] In combination with the second aspect, in one embodiment, the state of charge sensor of the battery further includes a second driving circuit, a second magnetic core, a fourth coil, and a fifth coil, as well as a capacitor and a resistor connected in series. The second magnetic core is coupled to the first magnetic core and has the same material as the first magnetic core. The fourth coil and the fifth coil are coupled to the second magnetic core. The fourth output terminal of the controller is connected to the input terminal of the second driving circuit. Two output terminals of the second driving circuit are connected to both ends of the fourth coil. The capacitor and the resistor are connected between both ends of the fifth coil.

[0035] In combination with the second aspect, in one embodiment, the controller is configured to send a second AC excitation signal to the second driving circuit, and the peak-to-valley value of the second AC excitation signal is less than or equal to the peak-to-valley value threshold. The controller is further configured to, after sending the second AC excitation signal to the second driving circuit, when the total harmonic distortion of the current in the fifth coil based on the frequency of the second AC excitation signal is greater than the total harmonic distortion threshold, send a third AC excitation signal to the second driving circuit. The peak-to-valley value of the third AC excitation signal is equal to the peak-to-valley value of the second AC excitation signal, and the frequency of the third AC excitation signal is equal to the resonance frequency of the capacitor and the fifth coil. The controller is further configured to gradually increase the peak-to-valley value of the third AC excitation signal after sending the third AC excitation signal to the second driving circuit. The controller is further configured to stop increasing the peak-to-valley value of the third AC excitation signal and send a fourth AC excitation signal to the first driving circuit when the effective value of the voltage across the fifth coil is less than or equal to the second voltage threshold. The peak-to-valley value of the fourth AC excitation signal is equal to the peak-to-valley value of the increased third AC excitation signal.

[0036] In combination with the second aspect, in one embodiment, the controller is further configured to send the second AC excitation signal to the second driving circuit after sending the fourth AC excitation signal to the first driving circuit and after a preset time threshold.

[0037] In a third aspect of the embodiments of the present application, a energy storage converter is provided. The energy storage converter includes a power conversion circuit and a state of charge (SOC) sensor of the battery. The AC side of the power conversion circuit is used to connect to the power grid. One end of the SOC sensor of the battery is connected to the positive DC terminal of the power conversion circuit, and the other end of the SOC sensor of the battery is used to connect to the positive electrode of the energy storage device. The negative DC terminal of the power conversion circuit is used to connect to the negative electrode of the energy storage device. Alternatively, one end of the SOC sensor of the battery is connected to the negative DC terminal of the power conversion circuit, and the other end of the SOC sensor of the battery is used to connect to the negative electrode of the energy storage device. The positive DC terminal of the power conversion circuit is used to connect to the positive electrode of the energy storage device. The SOC sensor of the battery is used to calculate the state of charge of the energy storage device, and the SOC sensor of the battery is the SOC sensor as described in the second aspect or any one of the embodiments of the second aspect above.

[0038] In a fourth aspect of the embodiments of the present application, a energy storage system is provided. The energy storage system includes an energy storage device and an energy storage converter connected to the energy storage device. The energy storage converter is used to perform power conversion on the direct current output by the energy storage device. The energy storage device is the energy storage device as described in the first aspect or any one of the embodiments of the first aspect above, or the energy storage converter is the energy storage converter as described in the third aspect or any one of the embodiments of the third aspect above.

[0039] The descriptions of the second aspect to the fourth aspect in the present application can refer to the detailed description of the first aspect; and, the beneficial effects of the second aspect to the fourth aspect can refer to the analysis of the beneficial effects of the first aspect, which will not be elaborated here. Description of the Drawings

[0040] Figure 1 It is a schematic curve diagram of the corresponding relationship between the terminal voltage and the SOC of a battery provided by the embodiments of the present application;

[0041] Figure 2 It is a schematic diagram of an application scenario of a state of charge (SOC) sensor of a battery provided by the embodiments of the present application;

[0042] Figure 3 It is a schematic diagram of another application scenario of a state of charge (SOC) sensor of a battery provided by the embodiments of the present application;

[0043] Figure 4 It is a schematic diagram of yet another application scenario of a state of charge (SOC) sensor of a battery provided by the embodiments of the present application;

[0044] Figure 5 It is a schematic diagram of still another application scenario of a state of charge (SOC) sensor of a battery provided by the embodiments of the present application;

[0045] Figure 6 It is a schematic circuit topology diagram of a state of charge (SOC) sensor of a battery provided by the embodiments of the present application;

[0046] Figure 7 Waveform schematic diagram of an alternating current excitation signal and an induced current provided by an embodiment of the present application;

[0047] Figure 8 Another circuit topology schematic diagram of a battery state of charge sensor provided by an embodiment of the present application;

[0048] Figure 9 Structural schematic diagram of a coil and a magnetic core coupling provided by an embodiment of the present application;

[0049] Figure 10 Equivalent magnetic circuit schematic diagram of a coil and a magnetic core coupling provided by an embodiment of the present application;

[0050] Figure 11 Another structural schematic diagram of a coil and a magnetic core coupling provided by an embodiment of the present application;

[0051] Figure 12 Another equivalent magnetic circuit schematic diagram of a coil and a magnetic core coupling provided by an embodiment of the present application;

[0052] Figure 13 Another circuit topology schematic diagram of a battery state of charge sensor provided by an embodiment of the present application;

[0053] Figure 14 Another structural schematic diagram of a coil and a magnetic core coupling provided by an embodiment of the present application;

[0054] Figure 15 Another equivalent magnetic circuit schematic diagram of a coil and a magnetic core coupling provided by an embodiment of the present application;

[0055] Figure 16 Another circuit topology schematic diagram of a battery state of charge sensor provided by an embodiment of the present application;

[0056] Figure 17 Another circuit topology schematic diagram of a battery state of charge sensor provided by an embodiment of the present application;

[0057] Figure 18 Another circuit topology schematic diagram of a battery state of charge sensor provided by an embodiment of the present application;

[0058] Figure 19 Another circuit topology schematic diagram of a battery state of charge sensor provided by an embodiment of the present application. Detailed implementation manners

[0059] The fabrication and use of the embodiments will be discussed in detail below. It should be understood, however, that many applicable inventive concepts provided by this application can be implemented in a variety of specific environments. The specific embodiments discussed are merely illustrative of specific ways of implementing and using this description and this technology, and do not limit the scope of this application.

[0060] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0061] Each circuit or other component may be described as or referred to as "configured to" perform one or more tasks. In this case, "configured to" is used to imply structure by indicating that the circuit / component includes the structure (e.g., circuitry) that performs one or more tasks during operation. Thus, even when the specified circuit / component is not currently operable (e.g., not turned on), the circuit / component can still be referred to as configured to perform the task. A circuit / component used in conjunction with the phrase "configured to" includes hardware, such as circuitry that performs the operations, etc.

[0062] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings in the embodiments of this application. In this application, "at least one" means one or more, and "a plurality" means two or more. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. Additionally, in the embodiments of this application, terms such as "first" and "second" do not limit the quantity and order.

[0063] In this application, words such as "exemplary" or "for example" are used to denote examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in this application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0064] Before introducing the embodiments of this application, the background technology related to this application will be introduced first.

[0065] As Figure 1 shown is a schematic curve diagram of the correspondence between the terminal voltage and the SOC of a battery provided by an embodiment of this application. As Figure 1 shown in (a) therein, when there is a special platform region in the correspondence between the terminal voltage and the SOC of the battery, the cell monomer sampling algorithm, the battery current ampere-hour integration method, or the series heterogeneous material battery method can be used to calculate the SOC of the battery.

[0066] The above-mentioned cell sampling algorithm refers to: by sampling the voltage and current of the cell, the SOC of the cell is calculated using the Kalman filtering method. However, for a battery pack including multiple cells, when calculating the SOC of the battery pack using the cell sampling algorithm, a large number of voltage sampling circuits and current sampling circuits need to be set up to sample the voltage and current of each cell, and a large amount of voltage and current data obtained by sampling needs to be processed. The large amount of data processing will result in a high cost for calculating the SOC of the battery pack.

[0067] The above-mentioned battery current ampere-hour integration method refers to: first, sampling the current of the battery, then performing analog-to-digital (A / D) conversion on the sampled current, and secondly performing time integration operation on the current after analog-to-digital conversion to determine the change in the charge amount of the battery. Finally, the SOC of the battery is calculated based on the change in the charge amount of the battery. However, the error will accumulate over time during the process of sampling the current of the battery using a current sensor, which will result in a large error in calculating the SOC. At the same time, generally, the measurement error of a current sensor is proportional to the measurement range, and it cannot maintain the same measurement accuracy under different measurement ranges. The larger the measurement range of the current sensor, the lower the measurement accuracy and the larger the measurement error. In order to reduce the error in calculating the SOC, a current sensor with higher accuracy needs to be used, such as a Hall current sensor or a fluxgate sensor. If the current sensor uses a Hall current sensor, due to the zero offset (zero-point offset) of the Hall sensor, it will also result in a large error in calculating the SOC. If the current sensor uses a fluxgate sensor, in order to reduce the error in calculating the SOC, a high requirement is imposed on the magnetic core material of the fluxgate sensor, which will result in a high cost. Among them, the zero offset of the Hall sensor means that in the ideal case without current, the Hall sensor should output a zero signal, but the Hall sensor outputs a non-zero signal. The zero offset of the Hall sensor is an offset error.

[0068] The above-mentioned series heterogeneous material battery method refers to: first, after the battery for which the SOC is to be calculated, a battery is connected in series in which there is an obvious linear correspondence between the terminal voltage and the SOC as shown in (b) of Figure 1 . For example, after a lithium iron phosphate battery for which the SOC is to be calculated, a lithium manganese oxide battery is connected in series. In the following embodiments, the battery for which the SOC is to be calculated is a lithium iron phosphate battery, and the series-connected battery is a lithium manganese oxide battery as an example for illustrative description. Then, according to the terminal voltage of the lithium manganese oxide battery at the current moment and the terminal voltage - SOC correspondence of the lithium manganese oxide battery, the SOC of the lithium manganese oxide battery at the current moment is determined. Secondly, according to the initial SOC of the lithium manganese oxide battery and the rated capacity of the lithium manganese oxide battery, the change in the charge amount Q 锰 of the lithium manganese oxide battery is calculated, so as to determine the change in the charge amount Q 铁 (Q 锰 = Q 铁)。Finally, according to the change in the charge amount Q of the lithium iron phosphate battery 铁 and SOC = SOC0 - Q 铁 / C, the SOC of the lithium iron phosphate at the current moment is calculated, where SOC0 is the initial value of the SOC of the lithium iron phosphate battery, and C is the rated capacity of the lithium iron phosphate battery. However, generally, the lithium iron phosphate battery is the main battery and the lithium manganese oxide battery is the auxiliary battery. The rated current of the lithium iron phosphate battery is greater than that of the lithium manganese oxide battery. In the process of calculating the SOC of the lithium iron phosphate battery by using the characteristics that the current of the series-connected batteries is the same and the change amount of the flowing charge amount is the same, the rated current of the lithium manganese oxide battery limits the current of the lithium iron phosphate, which will cause the power of the lithium iron phosphate battery to be limited. When this solution is applied to an energy storage system, the power density of the energy storage system will be reduced.

[0069] In summary, when calculating the SOC of a battery by using the above method, there are problems such as high cost, large error, inability to maintain the same measurement accuracy in different ranges, and reduction of the power density of the energy storage system. Based on this, the embodiments of the present application provide a battery charge sensor, which can accurately calculate the SOC of a battery when there is a special platform area in the corresponding relationship between the terminal voltage and the SOC of the battery, and at the same time has low cost, small error, can maintain the same measurement accuracy in different ranges, and when the battery state of charge sensor is applied to an energy storage system, it can avoid reducing the power density of the energy storage system.

[0070] As Figure 2 shown, it is a schematic diagram of an application scenario of a battery state of charge sensor 100 provided by the embodiments of the present application. The battery state of charge sensor 100 provided by the embodiments of the present application can be used as an independent device. Referring to Figure 2 , one end of the battery state of charge sensor 100 is used to connect to the positive electrode of the battery 200, and the other end of the battery state of charge sensor 100 is used to connect to the positive polarity end of the load 300, and the negative electrode of the battery 200 is connected to the negative polarity end of the load 300. Alternatively, one end of the battery state of charge sensor 100 is used to connect to the negative electrode of the battery 200, and the other end of the battery state of charge sensor 100 is used to connect to the negative polarity end of the load 300, and the positive electrode of the battery 200 is connected to the positive polarity end of the load 300. The embodiments of the present application do not limit the specific connection position of the battery state of charge sensor 100.

[0071] The above battery 200 can be a single battery cell, or can be a battery pack. Wherein, the battery pack can include multiple battery cells, and the multiple battery cells can be connected in series, parallel or in a hybrid connection manner. The embodiments of the present application do not limit the specific type of the battery 200.

[0072] As Figure 3As shown in the figure, it is a schematic diagram of another application scenario of the state of charge sensor 100 provided by the embodiment of the present application. The state of charge sensor 100 provided by the embodiment of the present application can be applied to the energy storage device 400. Refer to Figure 3 , the energy storage device 400 further includes a battery 200. One end of the state of charge sensor 100 is connected to the positive electrode of the battery 200, and the other end of the state of charge sensor 100 is used to be connected to the positive terminal of the load 300, and the negative electrode of the battery 200 is used to be connected to the negative terminal of the load 300. Alternatively, one end of the state of charge sensor 100 is connected to the negative electrode of the battery 200, and the other end of the state of charge sensor 100 is used to be connected to the negative terminal of the load 300, and the positive electrode of the battery 200 is used to be connected to the positive terminal of the load 300. The embodiment of the present application does not limit the specific connection position of the state of charge sensor 100 in the energy storage device 400.

[0073] In one implementation manner, refer to Figure 3 , the above-mentioned battery 200 is an electric core, and the above-mentioned energy storage device 400 is a battery pack.

[0074] As Figure 4 shown in the figure, it is a schematic diagram of yet another application scenario of the state of charge sensor 100 provided by the embodiment of the present application. The state of charge sensor 100 provided by the embodiment of the present application can also be applied to the energy storage converter (power conversion system, PCS) 500. The energy storage converter 500 further includes a power conversion circuit 510, and the AC side of the power conversion circuit 510 is used to be connected to the power grid 600. Refer to Figure 4 , one end of the state of charge sensor 100 is connected to the positive DC terminal of the power conversion circuit 510, the other end of the state of charge sensor 100 is used to be connected to the positive electrode of the energy storage device 400, and the negative DC terminal of the power conversion circuit 510 is used to be connected to the negative electrode of the energy storage device 400. Alternatively, one end of the state of charge sensor 100 is connected to the negative DC terminal of the power conversion circuit 510, the other end of the state of charge sensor 100 is used to be connected to the negative electrode of the energy storage device 400, and the positive DC terminal of the power conversion circuit 510 is used to be connected to the positive electrode of the energy storage device 400. The embodiment of the present application does not limit the specific connection position of the state of charge sensor 100 in the energy storage converter 500.

[0075] As Figure 5As shown in the figure, it is a schematic diagram of an application scenario of another state-of-charge sensor 100 provided by an embodiment of the present application. After the state-of-charge sensor 100 provided by the embodiment of the present application is applied to the energy storage device 400 and the energy storage converter 500, the energy storage device 400 or the energy storage converter 500 can be applied to the energy storage system 700. In this embodiment of the present application, it is taken as an example for illustrative purposes that both the energy storage device 400 and the energy storage converter 500 are applied to the energy storage system 700. The electrodes of the energy storage device 400 are connected to the DC terminal of the energy storage converter 500, and the AC terminal of the energy storage converter 500 is used to connect to the power grid 600.

[0076] As Figure 6 shown in the figure, it is a schematic diagram of the circuit topology of a state-of-charge sensor 100 provided by an embodiment of the present application. The state-of-charge sensor 100 includes a controller 111, a charging and discharging energy circuit 112, an energy storage element 120, a first magnetic core 130, at least one first driving circuit 140, and a first coil 150, a second coil 160, at least one third coil 170 and a plurality of magnetic sensors (181, 182,..., 18n) coupled to the first magnetic core 130. There is a linear correspondence between the terminal voltage and the state of charge of the energy storage element 120. At least one first driving circuit 140 includes a first driving circuit 141, and at least one third coil 170 includes a third coil 171. In this embodiment of the present application, the specific numbers of the first driving circuit, the third coil and the magnetic sensors included in the state-of-charge sensor 100 are not limited.

[0077] Among them, the linear correspondence between the terminal voltage and the state of charge of the energy storage element 120 means that: referring to Figure 1 as shown in (b) therein, the correspondence between the terminal voltage and the state of charge of the energy storage element 120 has good linearity, the terminal voltage and the state of charge of the energy storage element 120 are completely linearly corresponding, or the terminal voltage and the state of charge of the energy storage element 120 are almost linearly corresponding.

[0078] Referring to Figure 6 , the first coil 150 is used to be connected between the positive electrode of the battery 200 and the positive polarity terminal of the load 300. Or, the first coil 150 is used to be connected between the negative electrode of the battery 200 and the negative polarity terminal of the load 300. The first coil 150 can also be called a primary coil. In this embodiment of the present application, the specific connection position of the first coil 150 is not limited.

[0079] In one embodiment, the battery 200 may be a battery in which there is a special plateau region in the corresponding relationship between the terminal voltage and the state of charge, or the battery 200 may be a battery in which the terminal voltage and the state of charge are linearly corresponding. The embodiments of the present application do not limit this. The embodiments of the present application take the battery 200 in which there is a special plateau region in the corresponding relationship between the terminal voltage and the state of charge as an example for illustrative description.

[0080] Continuing to refer to Figure 6 , at least one first output terminal of the controller 111 is respectively connected to the input terminals of at least one first driving circuit 140, and the two output terminals of each first driving circuit are connected to both ends of a third coil. The output terminals of multiple magnetic sensors (181, 182,..., 18n) are respectively connected to multiple first input terminals of the controller 111, the second output terminal of the controller 111 is connected to the first controlled terminal of the energy charging and discharging circuit 112, the input-output terminal of the energy charging and discharging circuit 112 is connected to the first end of the second coil 160, and the second end of the second coil 160 is connected to the first end of the energy storage element 120. The second end of the energy storage element 120 is used to be connected to the ground terminal (ground, GND).

[0081] At least one driving circuit 140 is used to perform processing such as amplification and conversion on the AC excitation signal sent by the controller 111, so as to meet the power and form requirements for the operation of at least one third coil 170. Each third coil in the at least one third coil 170 can be called an excitation coil, and each third coil is used to generate an alternating magnetic field around it under the drive of the corresponding driving circuit.

[0082] The energy charging and discharging circuit 112 is used to charge the second coil 160 to increase the current flowing through the second coil 160, or discharge the second coil 160 to reduce the current flowing through the second coil 160.

[0083] The controller 111 is used to calculate the state of charge of the battery 200 according to the voltage change amount of the energy storage element 120.

[0084] In one embodiment, the type of each magnetic sensor in the above multiple magnetic sensors (181, 182,..., 18n) includes a coil, a Hall sensor, a fluxgate sensor, or a tunnel magneto-resistance (TMR) sensor. The embodiments of the present application do not limit the specific type of the magnetic sensor. In the following embodiments of the present application, each magnetic sensor is taken as a coil for illustrative description.

[0085] In one embodiment, the type of the energy storage element 120 includes a battery or a capacitor. The present application does not limit the specific type of the energy storage element 120. In the following embodiments of the present application, the energy storage element 120 is taken as a capacitor as an example for illustrative purposes.

[0086] In one embodiment, referring to Figure 6 , the controller 111 is configured to respectively send respective corresponding first AC excitation signals to at least one first drive circuit 140, so that at least one first drive circuit 140 can drive at least one third coil 170, so that the first magnetic core 130 is magnetized periodically.

[0087] In one embodiment, the above-mentioned first AC excitation signal and the types of other AC excitation signals in the following embodiments include positive and negative symmetric sine waves, triangular waves, trapezoidal waves, square waves or flat-topped waves. The present application does not limit the specific type of the AC excitation signal.

[0088] For each of the plurality of magnetic sensors (181, 182,..., 18n):

[0089] The controller 111 is further configured to determine the number of ampere-turns N of the first coil 150 when the effective value of the voltage across the magnetic sensor is less than or equal to the first voltage threshold, and the induced current in the magnetic sensor has an unsaturated characteristic at the positive peak of the corresponding first AC excitation signal and a saturated characteristic at the negative peak of the corresponding first AC excitation signal. p I p is less than the number of ampere-turns N of the second coil 160 k I k In this case, the charge and discharge energy circuit 112 is controlled to discharge energy to the second coil 160, so as to reduce the current flowing through the second coil 160 and reduce the number of ampere-turns N of the second coil 160 k I k .

[0090] Wherein, the effective value of the above voltage means that if an AC voltage and a DC voltage respectively pass through resistors with the same resistance value and generate equal heat in the same time, then the value of this DC voltage is called the effective value of the AC voltage.

[0091] The first voltage threshold is related to the material of the first magnetic core 130, and the first voltage threshold can be set according to needs. The present application does not limit the specific value of the first voltage threshold.

[0092] Such as Figure 7The figure shows a waveform schematic diagram of an AC excitation signal and an induced current provided by an embodiment of the present application. The fact that the induced current in the magnetic sensor has an unsaturated characteristic at the positive peak value of the corresponding first AC excitation signal means that the waveform of the induced current at the positive peak value of the corresponding first AC excitation signal is as shown in Figure 7 (b) in, and the waveform of the induced current is similar to the waveform of the AC excitation signal as shown in Figure 7 (a) in. The fact that the induced current in the magnetic sensor has a saturation characteristic at the negative peak value of the corresponding first AC excitation signal means that the waveform of the induced current at the negative peak value of the corresponding first AC excitation signal is as shown in Figure 7 (c) or (d) in, the waveform of the induced current is distorted, and the waveform of the induced current is not similar to the waveform of the AC excitation signal as shown in Figure 7 (a) in.

[0093] N p is the number of turns of the first coil 150 wound around the first magnetic core 130, I p is the current value of the current in the first coil 150, N k is the number of turns of the second coil 160 wound around the first magnetic core 130, I k is the current value of the current in the second coil 160. The embodiments of the present application do not limit the specific values of N p and N k .

[0094] The controller 111 is further configured to determine that the ampere-turns N p I p of the first coil 150 are greater than the ampere-turns N k I k of the second coil 160 when the effective value of the voltage across the magnetic sensor is less than or equal to the first voltage threshold, and the induced current in the magnetic sensor has a saturation characteristic at the positive peak value of the corresponding first AC excitation signal and an unsaturated characteristic at the negative peak value of the corresponding first AC excitation signal, and then control the charge and discharge circuit 112 to charge the second coil 160, thereby increasing the current flowing through the second coil 160 and increasing the ampere-turns N k I k of the second coil 160.

[0095] The controller 111 is further configured to, after controlling the charge and discharge circuit 112 to discharge the second coil 160 to reduce the ampere-turns N k I k of the second coil 160, or control the charge and discharge circuit 112 to charge the second coil 160 to increase the ampere-turns N k I kAfter that, when the effective value of the voltage across the magnetic sensor is greater than the above-mentioned first voltage threshold, the ampere-turns N of the first coil 150 are determined. p I p equals the ampere-turns N of the second coil 160. k I k In this case, the energy charging and discharging circuit 112 is controlled to stop discharging or charging the second coil 160 to maintain the ampere-turns N of the second coil 160. k I k stable and unchanged.

[0096] The controller 111 is further configured to determine the ampere-turns N of the first coil 150 when the effective value of the voltage across each of the multiple magnetic sensors (181, 182,..., 18n) is greater than its respective corresponding first voltage threshold. p I p equals the ampere-turns N of the second coil 160. k I k (N p I p = N k I k ), so that the current I in the first coil 150 p and the current I in the second coil 160 k are in a fixed ratio N k / N p (I p / I k = N k / N p ). The change amount of the charge quantity of the battery 200 and the change amount of the charge quantity of the energy storage element 120 are in a fixed ratio N k / N p . In this case, the voltage change amount of the energy storage element 120 is detected within a preset time, and the state of charge of the battery 200 is calculated. The specific value of the preset time in the embodiments of the present application is not limited.

[0097] In one implementation manner, the ampere-turns N of the first coil 150 p I p equals the ampere-turns N of the second coil 160. k I k means that: the ampere-turns N of the first coil 150 p I p and the ampere-turns N of the second coil 160 k I k are exactly equal, or the ampere-turns N of the first coil 150 p I p and the ampere-turns N of the second coil 160 k I kThe absolute value of the difference is less than or equal to the threshold of the difference in ampere-turns, and the threshold of the difference in ampere-turns can be a value close to 0. The specific value of the threshold of the difference in ampere-turns is not limited in the embodiments of the present application.

[0098] In one implementation, taking the energy storage element 120 as a capacitor as an example, the state of charge of the battery 200 satisfies the following formula:

[0099]

[0100] where SOC is the state of charge of the battery 200 at time t, SOC(t0) is the initial state of charge of the battery 200 at time t0, N p is the number of turns of the first coil 150 wound around the first magnetic core 130, N k is the number of turns of the second coil 160 wound around the first magnetic core 130, C is the capacitance of the energy storage element 120, Q is the rated capacity of the battery 200, U(t) is the terminal voltage of the energy storage element 120 at time t, and U(t0) is the initial terminal voltage of the energy storage element 120 at time t0.

[0101] Referring to Figure 6 , it can be understood that the current flowing through the first coil 150 is the same as the current flowing through the battery 200. Therefore, the change in the amount of charge flowing through the first coil 150 is the same as the change in the amount of charge of the battery 200, and both are the integral of the current I p in the first coil 150 with respect to time. The current flowing through the second coil 160 is the same as the current flowing through the energy storage element 120. Therefore, the change in the amount of charge flowing through the second coil 160 is the same as the change in the amount of charge of the energy storage element 120, and both are the integral of the current I k in the second coil 160 with respect to time. By mirroring the current I p in the first coil 150 proportionally to the current I k in the second coil 160, the change in the amount of charge of the energy storage element 120 is also proportional to the change in the amount of charge of the battery 200. Secondly, there is a linear correspondence between the terminal voltage and the state of charge of the energy storage element 120. The terminal voltage of the energy storage element 120 at the current moment can be used to determine the state of charge of the energy storage element 120 at the current moment, so as to determine the change in the amount of charge of the energy storage element 120. Further, according to the proportional relationship between the change in the amount of charge of the energy storage element 120 and the change in the amount of charge of the battery 200, the change in the amount of charge of the battery 200 can be determined. Therefore, finally, the state of charge of the battery 200 can be calculated according to the change in the amount of charge of the battery 200. And, according to the above formula for calculating the state of charge of the battery 200, there is a linear correspondence between the terminal voltage of the energy storage element 120 and the state of charge of the battery 200, and the terminal voltage of the energy storage element 120 can also be directly used to indicate the state of charge of the battery 200.

[0102] In one embodiment, taking the energy storage element 120 as a capacitor as an example, the capacitance C of the energy storage element 120 satisfies the following formula:

[0103]

[0104] Taking the rated capacity Q of the battery 200 as 314 ampere-hours (Ah), the initial state of charge SOC(t0) of the battery 200 at time t0 is 1, the initial terminal voltage U(t0) of the energy storage element 120 is 3.5V, the state of charge SOC of the battery 200 at time t is 0, the terminal voltage U(t) of the energy storage element 120 is 2.8V, and the turns ratio of the second coil 160 to the first coil 150 is 1000 (N k / N p = 1000) as an example, as shown below:

[0105]

[0106] The capacitance C of the energy storage element 120 can be 1615F. It can be understood that since there is a proportional relationship between the change amount of the charge quantity of the energy storage element 120 and the change amount of the charge quantity of the battery 200, the capacity of the energy storage element 120 can be reduced, thereby reducing the volume of the state of charge sensor 100 of the battery and lowering the cost of the state of charge sensor 100 of the battery.

[0107] In one embodiment, as Figure 8 shown is another circuit topology schematic diagram of the state of charge sensor 100 of the battery provided by the embodiment of the present application. The above charging and discharging energy circuit 112 includes a first switching tube Q1 and a second switching tube Q2. The third output terminal of the controller 111 is connected to the second controlled terminal of the charging and discharging energy circuit 112. The controlled terminal of the first switching tube Q1 is connected to the first controlled terminal of the charging and discharging energy circuit 112. The controlled terminal of the second switching tube Q2 is connected to the second controlled terminal of the charging and discharging energy circuit 112. The first terminal of the first switching tube Q1 is used to receive a positive reference voltage Vref+, such as a reference voltage of +15V. The first terminal of the second switching tube Q2 is used to receive a negative reference voltage Vref-, such as a reference voltage of -15V. The second terminal of the first switching tube Q1 and the second terminal of the second switching tube Q2 are connected. The second terminal of the first switching tube Q1 is connected to the input-output terminal of the charging and discharging energy circuit 112.

[0108] Refer to Figure 8, when the above-mentioned controller 111 controls the energy release circuit 112 to release energy to the second coil 160, it means that the controller 111 controls the second switch tube Q2 to conduct, so that the second coil 160 receives the negative reference voltage Vref- through the second switch tube Q2 to release energy. When the above-mentioned controller 111 controls the energy storage and release circuit 112 to charge the second coil 160, it means that the controller 111 controls the first switch tube Q1 to conduct, so that the second coil 160 receives the positive reference voltage Vref+ through the first switch tube Q1 to charge. When the above-mentioned controller 111 controls the energy storage and release circuit 112 to stop releasing or charging the second coil 160, it means that the controller 111 controls the first switch tube Q1 and the second switch tube Q2 to conduct alternately for the same time.

[0109] In one embodiment, the type of the above-mentioned first switch tube Q1 or second switch tube Q2 includes a metal-oxide-semiconductor field-effect transistor (MOSFET), which can also be simply referred to as MOS, an insulated-gate bipolar transistor (IGBT) or a triode. The embodiments of the present application do not limit the specific type of the first switch tube Q1 or the second switch tube Q2.

[0110] In one embodiment, as Figure 9 shown is a schematic structural diagram of the coupling between a coil and a magnetic core provided by an embodiment of the present application. The above-mentioned first magnetic core 130 may include a plurality of sub-magnetic cores (131, 132,..., 13n), at least one first driving circuit 140 may include a plurality of first driving circuits, at least one third coil 170 may include a plurality of third coils (171, 172,..., 17n), the plurality of third coils (171, 172,..., 17n) are respectively wound around the plurality of sub-magnetic cores (131, 132,..., 13n), and the plurality of magnetic sensors (181, 182,..., 18n) are respectively coupled to the plurality of sub-magnetic cores (131, 132,..., 13n). The first coil 150 and the second coil 160 are both wound around the plurality of sub-magnetic cores (131, 132,..., 13n) in sequence, where n is a positive integer, and the embodiments of the present application do not limit the specific value of n.

[0111] On the basis of Figure 9 , as Figure 10 shown is an equivalent magnetic circuit schematic diagram of the coupling between a coil and a magnetic core provided by an embodiment of the present application. Referring to Figure 9 and Figure 10 :

[0112] The current in the first coil 150 is I p, the number of turns of the first coil 150 wound around the sub-core 131 is N p1 , N p1 I p is the ampere-turns of the first coil 150 in the sub-core 131. The number of turns of the first coil 150 wound around the sub-core 13n is N pn , N pn I p is the ampere-turns of the first coil 150 in the sub-core 13n.

[0113] The current in the second coil 160 is I k , the number of turns of the second coil 160 wound around the sub-core 131 is N k1 , N k1 I k is the ampere-turns of the second coil 160 in the sub-core 131. The number of turns of the second coil 160 wound around the sub-core 13n is N kn , N kn I k is the ampere-turns of the second coil 160 in the sub-core 13n.

[0114] In the sub-core 131, the current flowing through the third coil 171 is I e1 , the number of turns of the third coil 171 wound around the sub-core 131 is N e1 , N e1 I e1 is the ampere-turns of the third coil 171 in the sub-core 131. In the sub-core 13n, the current flowing through the third coil 17n is I en , the number of turns of the third coil 17n wound around the sub-core 13n is N en , N en I en is the ampere-turns of the third coil 17n in the sub-core 13n.

[0115] In the sub-core 131, the current flowing through the magnetic sensor 181 is I s1 , the number of turns of the magnetic sensor 181 wound around the sub-core 131 is N s1 , N s1 I s1 is the ampere-turns of the magnetic sensor 181 in the sub-core 131. In the sub-core 13n, the current flowing through the magnetic sensor 18n is I sn , the number of turns of the magnetic sensor 18n wound around the sub-core 13n is N sn , N sn I sn is the ampere-turns of the magnetic sensor 18n in the sub-core 13n.

[0116] In the sub-core 131, the magnetic resistance in the magnetic circuit is equivalent to R1. In the sub-core 13n, the magnetic resistance of the magnetic circuit is equivalent to Rn.

[0117] When multiple sub-cores (131, 132, …, 13n) are saturated respectively, the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the multiple sub-cores (131, 132, …, 13n) increases successively. For example, when the sub-core 131 is saturated, the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the sub-core 131, |N p1 I p -N k1 I k |, is less than the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the sub-core 132 when the sub-core 132 is saturated, |N p2 I p -N k2 I k |.

[0118] The measurement range of the state of charge sensor 100 of the battery is related to the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the sub-core 13n when the sub-core 13n is saturated, |N pn I p -N kn I k |. The larger this |N pn I p -N kn I k | is, the wider the magnetic field strength range that the sub-core 13n can respond to and measure, and the larger the measurement range of the state of charge sensor 100 of the battery. The smaller this |N pn I p -N kn I k | is, the narrower the magnetic field strength range that the sub-core 13n can respond to and measure, and the smaller the measurement range of the state of charge sensor 100 of the battery.

[0119] The measurement accuracy of the state of charge sensor 100 of the battery is related to the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the sub-core 13n when the sub-core 13n is saturated, |N p1 I p -N k1 I k |. The larger this |N p1 I p -N k1 I k | is, the lower the accuracy of the state of charge sensor 100 of the battery. The larger this |N p1 I p -N k1 I k | is, the higher the accuracy of the state of charge sensor 100 of the battery.

[0120] Understandably, the state of charge sensor 100 provided by the embodiments of the present application has n ranges, and the measurement accuracies of the n ranges are all related to the absolute value |N p1 I p -N k1 I k | of the difference between the ampere-turns of the first coil 150 and the ampere-turns of the second coil 160 in the sub-core 131 when the sub-core 131 is saturated. The n ranges have the same measurement accuracy, so they can be used to calculate the state of charge of batteries 200 with different rated capacities, and the measurement accuracies are the same. The versatility and reliability of the state of charge sensor 100 are relatively high.

[0121] In one embodiment, when each sub-core is saturated, the absolute value of the difference between the ampere-turns of the first coil 150 and the ampere-turns of the second coil 160 is related to the shape and material of the sub-core, the number of turns of the coil wound around the sub-core, and the length of the air gap in the sub-core. The air gap in the sub-core refers to the slot in the sub-core. Specifically, the larger the volume of the sub-core, the larger the absolute value of the difference in ampere-turns; the fewer the number of turns of the coil wound around the sub-core, the larger the absolute value of the difference in ampere-turns; the longer the air gap in the sub-core, the larger the absolute value of the difference in ampere-turns. The range or measurement accuracy of the state of charge sensor 100 can be adjusted by changing the shape and material of each sub-core, the number of turns of the coil wound around the sub-core, or the length of the air gap in the sub-core.

[0122] In one embodiment, the types of multiple sub-cores (131, 132,..., 13n) include toroidal cores, E-shaped cores, I-shaped cores, or I-shaped cores, etc. The embodiments of the present application do not limit the specific types of the multiple sub-cores (131, 132,..., 13n). Refer to Figure 9 In the embodiments of the present application, taking the multiple sub-cores (131, 132,..., 13n) as toroidal magnets as an example, an exemplary description is given.

[0123] In one embodiment, the materials of the multiple sub-cores (131, 132,..., 13n) and the other cores in the embodiments of the present application include ferrite, iron powder core, or nano amorphous material. The embodiments of the present application do not limit the specific materials of the cores.

[0124] In one embodiment, as Figure 11The figure shows another structural schematic diagram of the coupling between a coil and a magnetic core provided by an embodiment of the present application. The first magnetic core 130 includes a first magnetic column B1 and a plurality of second magnetic columns (C1, C2,..., Cn) arranged in sequence. At least one first driving circuit 140 includes a first driving circuit 141, and at least one third coil 170 includes a third coil 171. The first driving circuit 141 is used to drive the third coil 171. The first coil 150, the second coil 160, and the third coil 171 are all wound around the first magnetic column B1, and a plurality of magnetic sensors (181, 182,..., 18n) are respectively coupled to the plurality of second magnetic columns (C1, C2,..., Cn).

[0125] Based on Figure 11 , as shown in Figure 12 , the figure shows another equivalent magnetic circuit schematic diagram of the coupling between a coil and a magnetic core provided by an embodiment of the present application. Referring to Figure 11 and Figure 12 :

[0126] The current in the first coil 150 is I p , and the number of turns of the first coil 150 wound around the first magnetic column B1 is N p , and N p I p is the ampere-turns of the first coil 150.

[0127] The current in the second coil 160 is I k , and the number of turns of the second coil 160 wound around the first magnetic column B1 is N k , and N k I k is the ampere-turns of the second coil 160.

[0128] The current in the third coil 171 is I e , and the number of turns of the third coil 171 wound around the first magnetic column B1 is N e , and N e I e is the ampere-turns of the third coil 171.

[0129] In the second magnetic column C1, the current flowing through the magnetic sensor 181 is I s1 , and the number of turns of the magnetic sensor 181 wound around the second magnetic column C1 is N s1 , and N s1 I s1 is the ampere-turns of the magnetic sensor 181 in the second magnetic column C1. In the second magnetic column Cn, the current flowing through the magnetic sensor 18n is I sn , and the number of turns of the magnetic sensor 18n wound around the second magnetic column Cn is N sn , and N sn I sn is the ampere-turns of the magnetic sensor 18n in the second magnetic column Cn.

[0130] The magnetic resistance of the magnetic circuit in the first magnetic column B1 is equivalently R em , and the magnetic resistances of the magnetic circuits in the multiple second magnetic columns (C1, C2,..., Cn) are equivalently (R1, R2,..., Rn) respectively, and the magnetic resistances of the magnetic circuits between the multiple second magnetic columns (C1, C2,..., Cn) are equivalently (Rx1, Rx2,..., Rx(n - 1)) respectively.

[0131] Along the direction away from the first magnetic column B1, when the multiple second magnetic columns (C1, C2,..., Cn) are saturated respectively, the absolute value of the difference between the ampere-turns of the corresponding first coil 150 and the second coil 160 increases in sequence. For example, when the second magnetic column C1 is saturated, the absolute value of the difference between the ampere-turns of the corresponding first coil 150 and the second coil 160 |N p I p -N k I k |1 is less than the absolute value of the difference between the ampere-turns of the corresponding first coil 150 and the second coil 160 |N p I p -N k I k |2 when the second magnetic column C2 is saturated.

[0132] The range of the state of charge sensor 100 of the battery is related to the absolute value of the difference between the ampere-turns of the corresponding first coil 150 and the second coil 160 |N p I p -N k I k | n . The larger this |N p I p -N k I k | n , the wider the range of the magnetic field intensity that the second magnetic column Cn can respond to and measure, the larger the range of the state of charge sensor 100 of the battery. The smaller this |N p I p -N k I k | n , the narrower the range of the magnetic field intensity that the second magnetic column Cn can respond to and measure, and the smaller the range of the state of charge sensor 100 of the battery.

[0133] The measurement accuracy of the state of charge sensor 100 of the battery is related to the absolute value of the difference between the ampere-turns of the corresponding first coil 150 and the second coil 160 |N p I p -N k I k|1 is related to the following, the|N p I p -N k I k |1 The larger it is, the lower the accuracy of the state - of - charge sensor 100 of the battery, and the|N p I p -N k I k |1 The smaller it is, the higher the accuracy of the state - of - charge sensor 100 of the battery.

[0134] It can be understood that the state - of - charge sensor 100 provided by the embodiments of the present application has n ranges, and the measurement accuracies of these n ranges are all related to the absolute value of the difference between the ampere - turns of the first coil 150 and the ampere - turns of the second coil 160 corresponding to when the second magnetic column C1 is saturated, and the|N p I p -N k I k |1 is related. These n ranges have the same measurement accuracy, so they can be used to calculate the state of charge of batteries 200 with different rated capacities, and the measurement accuracies are the same. The versatility and reliability of the state - of - charge sensor 100 are relatively high.

[0135] In one implementation, when each second magnetic column is saturated, the absolute value of the difference between the ampere - turns of the first coil 150 and the ampere - turns of the second coil 160 corresponding to it is related to the cross - sectional area, magnetic permeability or magnetic path length of the second magnetic column, etc. The range or measurement accuracy of the state - of - charge sensor 100 can be adjusted by adjusting the cross - sectional area, magnetic permeability or magnetic path length of the second magnetic column.

[0136] In one implementation, the type of the first magnetic core 130 includes a snap - type magnetic core, or other magnetic cores with multiple magnetic columns. The embodiments of the present application do not limit the specific type of the first magnetic core 130. Refer to Figure 11 The embodiments of the present application take the first magnetic core 130 as a snap - type magnetic core as an example for illustrative purposes.

[0137] In one implementation, the type of the controller 111 includes an analog - to - digital hybrid circuit such as a micro control unit (MCU), a digital signal processor (DSP), or a field programmable gate array (FPGA). The embodiments of the present application do not limit the specific type of the controller 111.

[0138] The state-of-charge sensor 100 provided by the embodiment of the present application has a linear correspondence between the terminal voltage of the energy storage element 120 and the state of charge. When there is a special plateau region in the correspondence between the terminal voltage of the battery 200 and the state of charge, multiple magnetic sensors (181, 182,..., 18n), the first switching transistor Q1, and the second switching transistor Q2 can be used to accurately make the ampere-turns N p I p of the first coil 150 equal to the ampere-turns N k I k of the second coil 160, so as to accurately make the change amount of the electric charge of the battery 200 and the change amount of the electric charge of the energy storage element 120 have a fixed ratio N k / N p . Thus, the state of charge of the battery 200 can be accurately and highly precisely calculated by detecting the change amount of the voltage of the energy storage element 120 within a preset time. Compared with the above-mentioned cell sampling algorithm, it is not necessary to sample the voltage and current of each cell in the battery 200 and process a large amount of voltage and current data obtained by sampling, so the cost is lower. Compared with the above-mentioned battery current ampere-hour integration method, in the state-of-charge sensor 100 of the present application, the state of charge of the battery 200 is calculated according to the change amount of the voltage of the energy storage element 120, which can avoid the accumulation of errors over time during the sampling of the current by the current sensor, and can improve the detection accuracy. Secondly, the same measurement accuracy can be achieved under different ranges through multiple magnetic sensors (181, 182,..., 18n), and the versatility and reliability are relatively high. Finally, during the process of calculating the state of charge of the battery 200, it is not necessary to use a Hall sensor to sample the current, which can avoid the zero bias of the Hall sensor and improve the detection accuracy. It is not necessary to use a fluxgate sensor with relatively high material requirements, so the cost is lower. Compared with the above-mentioned series heterogeneous battery method, the current of the energy storage element 120 will not limit the current of the battery 200, and the power limitation of the battery 200 can be avoided. When the state-of-charge sensor 1000 provided by the embodiment of the present application is applied to the energy storage system 700, the power density of the muck system can be avoided from being reduced.

[0139] In one implementation, referring to Figure 11 , since temperature will affect the saturation magnetic flux and magnetic permeability of the first magnetic column B1 and multiple second magnetic columns (C1, C2,..., Cn) in the first magnetic core 130. For example, an increase in temperature will reduce the saturation magnetic flux of the first magnetic core 130 and reduce the detection accuracy of the state of charge of the battery 200. On Figure 8 's basis, as Figure 13The following is a schematic circuit topology diagram of another state of charge sensor 100 provided by an embodiment of the present application. The state of charge sensor 100 further includes a second drive circuit 190, a second magnetic core 1100, a fourth coil 1110, and a fifth coil 1120, as well as a capacitor C and a resistor R connected in series. The second magnetic core 1100 is coupled to the first magnetic core 130.

[0140] Among them, the second magnetic core 1100 and the first magnetic core 130 are made of the same material. Therefore, when the temperature changes, the saturation magnetic flux and magnetic permeability of the second magnetic core 1100 and the first magnetic core 130 change in the same way. The fourth coil 1110 can be referred to as an excitation coil, and the fifth coil 1120 can be referred to as a detection coil. The circuit composed of the second drive circuit 190, the second magnetic core 1100, the fourth coil 1110, the fifth coil 1120, the capacitor C, and the resistor R can be referred to as a temperature drift compensation circuit. The temperature drift compensation circuit is used for dynamic compensation of the saturation magnetic flux and magnetic permeability of the first magnetic core 130. The principle is based on zero phase angle (ZPA) frequency amplitude tracking of coupled coils to dynamically detect the mutual inductance and self-inductance changes of the fifth coil 1120, thereby dynamically compensating the saturation magnetic flux and magnetic permeability of the first magnetic core 130.

[0141] Refer to Figure 13 , the fourth coil 1110 and the fifth coil 1120 are coupled to the second magnetic core 1100. The fourth output terminal of the controller 111 is connected to the input terminal of the second drive circuit 190. The two output terminals of the second drive circuit 190 are connected to both ends of the fourth coil 1110. The capacitor C and the resistor R are connected between both ends of the fifth coil 1120.

[0142] In Figure 13 On the basis of, as Figure 14 shown is a schematic diagram of another structure of the coupling between a coil and a magnetic core provided by an embodiment of the present application. The second magnetic core 1100 includes a third magnetic post 1101 and a fourth magnetic post 1102. The fourth coil 1110 is wound around the third magnetic post 1101, and the fifth coil 1120 is wound around the fourth magnetic post 1102.

[0143] In Figure 14 On the basis of, as Figure 15 shown is an equivalent magnetic circuit diagram of another coupling between a coil and a magnetic core provided by an embodiment of the present application.

[0144] Refer to Figure 14 and Figure 15 :

[0145] The current flowing through the fourth coil 1110 is i et , the number of turns of the fourth coil 1110 wound around the third magnetic post 1101 is N et , N et i etis the ampere-turns of the fourth coil 1110.

[0146] The current flowing through the fifth coil 1120 is Isignt, and the number of turns of the fifth coil 1120 wound around the fourth magnetic column 1102 is Nsignt, where NsigntIsignt is the ampere-turns of the fifth coil.

[0147] The magnetic resistance of the magnetic circuit in the third magnetic column 1101 is equivalent to Ret, and the magnetic resistance of the magnetic circuit in the fourth magnetic column 1102 is equivalent to Rsignt.

[0148] Reference Figure 13 The controller 111 is used to send a second AC excitation signal to the second driving circuit 190, and the peak-to-valley value of the second AC excitation signal is less than or equal to the peak-to-valley value threshold.

[0149] In one embodiment, the second drive circuit 190 receives the second AC excitation signal and drives the fourth coil 1110 to generate a magnetic flux that is much smaller than the saturation magnetic flux of the second magnetic core 1100. The peak-to-valley threshold is related to the saturation magnetic flux of the second magnetic core 1100. The embodiment of the present application does not limit the specific value of the peak-to-valley threshold.

[0150] The controller 111 is further configured to, after sending the second AC excitation signal to the second drive circuit 190, cause the current in the fifth coil 1120 to be at a frequency f of the second AC excitation signal. t When the total harmonic distortion (THD) of the fundamental wave is greater than the total harmonic distortion threshold, a third AC excitation signal is sent to the second driving circuit 190, the peak-to-valley value of the third AC excitation signal is equal to the peak-to-valley value of the second AC excitation signal, and the frequency of the third AC excitation signal is equal to the resonant frequency f of the capacitor C and the fifth coil 1120. rt The embodiment of the present application does not limit the specific value of the total harmonic distortion threshold.

[0151] The controller 111 is further configured to gradually increase the peak-to-valley value of the third AC excitation signal after sending the third AC excitation signal to the second drive circuit 190 .

[0152] Since the saturation magnetic flux and magnetic permeability of the second magnetic core 1100 are related to the mutual inductance value of the fifth coil 1120, the mutual inductance value of the fifth coil 1120 satisfies the following formula:

[0153] M=V signt1 / (2πf rt i et )

[0154] Wherein, M is the mutual inductance of the fifth coil 1120, V signt1 is the effective value of the voltage across the resistor R, Vsignt1 can be used to indicate the effective value V of the voltage across the fifth coil 1120 signt2 , where π is the ratio of a circle's circumference to its diameter, and f rt is the resonance frequency of the capacitor C and the fifth coil 1120, and i et is the amplitude of the third excitation signal. Therefore, the effective value V of the voltage across the fifth coil 1120 signt2 can be used to indicate the mutual inductance value of the fifth coil 1120, and can also be used to indicate the saturation magnetic flux and magnetic permeability of the second magnetic core 1100 or the first magnetic core 130.

[0155] The controller 111 is also used to detect the effective value V of the voltage across the fifth coil 1120 signt2 , and when the effective value V of the voltage across the fifth coil 1120 signt2 is less than or equal to the second voltage threshold, it stops increasing the peak-to-valley value of the third AC excitation signal and sends a fourth AC excitation signal to the first drive circuit 141. The peak-to-valley value of the fourth AC excitation signal is equal to the increased peak-to-valley value of the third AC excitation signal, so that both the second magnetic core 1100 and the first magnetic core 130 reach the saturation state again, and the saturation magnetic flux and magnetic permeability of the first magnetic column B1 and the plurality of second magnetic columns (C1, C2,..., Cn) in the first magnetic core 130 are stabilized again, thereby improving the detection accuracy of the state of charge of the battery 200. The embodiments of the present application do not limit the specific value of the second voltage threshold.

[0156] In one embodiment, referring to Figure 13 , after the controller 111 sends the fourth AC excitation signal to the first drive circuit 141 and after a preset time threshold, it sends the above-mentioned second AC excitation signal to the second drive circuit 190 and repeats the above steps. Thus, the saturation magnetic flux and magnetic permeability of the first magnetic column B1 and the plurality of second magnetic columns (C1, C2,..., Cn) in the first magnetic core 130 can be compensated periodically, ensuring the detection accuracy of the state of charge of the battery 200 at different times and different temperatures. The above preset time threshold is related to the compensation period, and the embodiments of the present application do not limit the specific value of the preset time threshold.

[0157] In one embodiment, the type of the second magnetic core 1100 includes snap-on magnetic cores, toroidal magnetic cores, E-shaped magnetic cores, I-shaped magnetic cores, or I-shaped magnetic cores, etc. The embodiments of the present application do not limit the specific type of the second magnetic core 1100. Referring to Figure 14 The embodiments of the present application take the second magnetic core 1100 as a snap-on magnetic core as an example for illustrative description.

[0158] The state of charge sensor 100 provided by the embodiment of the present application. The second magnetic core 1100 is made of the same material as the first magnetic core 130. Through the temperature drift compensation circuit composed of the second drive circuit 190, the second magnetic core 1100, the fourth coil 1110, the fifth coil 1120, the capacitor C and the resistor R, when the temperature affects the saturation magnetic flux and magnetic permeability of the first magnetic column B1 and the plurality of second magnetic columns (C1, C2,..., Cn) in the first magnetic core 130, the saturation magnetic flux and magnetic permeability of the first magnetic core 130 can be made stable again, so that the detection accuracy of the state of charge of the battery 200 can be improved.

[0159] In one embodiment, on the basis of Figure 8 as Figure 16 shown is a circuit topology schematic diagram of another state of charge sensor 100 provided by the embodiment of the present application. The state of charge sensor 100 further includes a plurality of switches (K1, K2,..., Kn), and a first inductor L1 and a plurality of second inductors (L21, L22, L2n) connected in series. The first inductor L1 and the plurality of second inductors (L21, L22, L2n) are connected between the second end of the first switching tube Q1 and the input and output ends of the energy charging and discharging circuit 112. The plurality of switches (K1, K2,..., Kn) are respectively connected in parallel with the plurality of second inductors (L21, L22, L2n).

[0160] In one embodiment, the types of the above-mentioned plurality of switches (K1, K2,..., Kn) include relays, MOS or IGBT, and the embodiment of the present application does not limit the specific types of the plurality of switches (K1, K2,..., Kn).

[0161] In one embodiment, referring to Figure 9 and Figure 16 , when the plurality of sub-magnetic cores (131, 132,..., 13n) are saturated respectively, the larger the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the plurality of sub-magnetic cores (131, 132,..., 13n), the more switches (K1, K2,..., Kn) can be controlled to conduct, so as to increase the ampere-turns N k I k of the second coil 160. For example, when the sub-magnetic core 131 is saturated, the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the sub-magnetic core 131 |N p1 I p -N k1 I k | is small, and fewer switches (K1, K2,..., Kn) can be controlled to conduct. When the sub-magnetic core 13n is saturated, the absolute value of the difference between the ampere-turns of the first coil 150 and the second coil 160 in the sub-magnetic core 13n |Npn I p -N kn I k is relatively large, and more switches (K1, K2, …, Kn) can be controlled to conduct. The embodiments of the present application do not limit the specific number of switches (K1, K2, …, Kn) controlled to conduct.

[0162] The state of charge sensor 100 provided by the embodiments of the present application can control the charging or discharging speed of the second coil 160 by controlling the number of switches (K1, K2, …, Kn) that conduct, and can achieve multi-gear control of the ampere-turns N of the second coil 160 k I k adjustment speed, which can improve the adaptability and detection efficiency of the state of charge sensor 100.

[0163] In one implementation manner, on the basis of Figure 13 as shown in (a) of Figure 17 , or, on the basis of Figure 16 as shown in (b) of Figure 17 , is a circuit topology schematic diagram of another state of charge sensor 100 provided by the embodiments of the present application. The state of charge sensor 100 further includes a first operational amplifier A1. The second output terminal of the controller 111 is connected to the non-inverting input terminal of the first operational amplifier A1, the third output terminal of the controller 111 is connected to the inverting input terminal of the first operational amplifier A1, the positive power supply terminal of the first operational amplifier A1 is used to receive the positive reference voltage Vref+, the negative power supply terminal of the first operational amplifier A1 is used to receive the negative reference voltage Vref-, and the output terminal of the first operational amplifier A1 is connected to the controlled terminals of the first switching transistor Q1 and the second switching transistor Q2.

[0164] Among them, the first switching transistor Q1 is an NPN-type triode, NMOS or NIGBT. The second switching transistor Q2 is a PNP-type triode, PMOS or PIGBT. The controlled terminals of the first switching transistor Q1 and the second switching transistor Q2 are both bases or gates, the first ends of the first switching transistor Q1 and the second switching transistor Q2 are both collectors or drains, and the second ends of the first switching transistor Q1 and the second switching transistor Q2 are both emitters or sources. The embodiments of the present application do not limit the specific types of the first switching transistor Q1 and the second switching transistor Q2. Referring to Figure 17 in (a) of Figure 17 in (b), the embodiments of the present application take the first switching transistor Q1 as an NPN-type triode and the second switching transistor Q2 as a PNP-type triode as an example for illustrative description.

[0165] In one implementation manner, as shown in (a) of Figure 17 orFigure 17 As shown in (b) of , the charge and discharge circuit 112 further includes a first diode D1 and a second diode D2. The anode of the first diode D1 and the cathode of the second diode D2 are connected to the second end of the first switching transistor Q1. The cathode of the first diode D1 is connected to the first end of the first switching transistor Q1. The anode of the second diode D2 is connected to the first end of the second switching transistor Q2. The first diode D1 and the second diode D2 are used to provide a freewheeling path to protect the first switching transistor Q1 and the second switching transistor Q2, thereby improving the reliability of the state of charge sensor 100 of the battery.

[0166] For the state of charge sensor 100 of the battery provided by the embodiments of the present application, the first operational amplifier A1 is used to drive the first switching transistor Q1 and the second switching transistor Q2 simultaneously, eliminating the need to set up two driving circuits to drive the first switching transistor Q1 and the second switching transistor Q2 respectively, thus reducing the circuit complexity and cost.

[0167] In one embodiment, on the basis of Figure 17 in (b), as Figure 18 shown, it is a schematic circuit topology diagram of another state of charge sensor 100 of the battery provided by the embodiments of the present application. The state of charge sensor 100 of the battery further includes a current sensor 1130. One end of the current sensor 1130 is connected to the second end of the energy storage element 120. The other end of the current sensor 1130 is used to be connected to the ground terminal. The output terminal of the current sensor 1130 is connected to the second input terminal of the controller 111.

[0168] In one embodiment, the type of the current sensor 1130 includes a Hall sensor, a fluxgate sensor or a tunneling magnetoresistance sensor. The embodiments of the present application do not limit the specific type of the current sensor 1130.

[0169] For the state of charge sensor 100 of the battery provided by the embodiments of the present application, the current sensor 1130 is used to detect the current flowing through the second coil 160 and the energy storage element 120. When calculating the state of charge of the battery 200, the controller 111 can correct the calculation result according to this current, further improving the accuracy of the state of charge calculation of the battery 200.

[0170] In one embodiment, on the basis of Figure 17 in (b), as Figure 19The following is a schematic circuit topology diagram of another state-of-charge sensor 100 provided by an embodiment of the present application. The state-of-charge sensor 100 further includes a current sensor 1130 and a second operational amplifier A2. One end of the current sensor 1130 is connected to the second end of the second coil 160, and the other end of the current sensor 1130 is used to be connected to the ground terminal. The output end of the current sensor 1130 is connected to the input end of the second operational amplifier A2, and the output end of the second operational amplifier A2 is connected to the first end of the energy storage element 120.

[0171] For the state-of-charge sensor 100 provided by the embodiment of the present application, the current sensor 1130 shunts the current flowing through the second coil 160, and the shunted current charges or discharges the energy storage element 120 after passing through the second operational amplifier A2. The ratio between the change amount of the charge quantity of the battery 200 and the change amount of the charge quantity of the energy storage element 120, in addition to the turn ratio of the first coil 150 and the second coil 160, increases the amplification factor of the second operational amplifier A2. Thus, the ratio multiple between the change amount of the charge quantity of the battery 200 and the change amount of the charge quantity of the energy storage element 120 is larger, a smaller-capacity energy storage element 120 can be adopted, the volume of the state-of-charge sensor 100 can be reduced, and the cost of the state-of-charge sensor 100 can be lowered.

[0172] Based on this, referring to Figure 3 , the embodiment of the present application further provides an energy storage device 400. The energy storage device 400 includes a battery 200 and a state-of-charge sensor 100. The state-of-charge sensor 100 is used to calculate the state of charge of the battery 200. One end of the state-of-charge sensor 100 is connected to the positive electrode of the battery 200, and the other end of the state-of-charge sensor 100 is used to be connected to the positive-polarity terminal of the load 300. The negative electrode of the battery 200 is used to be connected to the negative-polarity terminal of the load 300. Alternatively, one end of the state-of-charge sensor 100 is connected to the negative electrode of the battery 200, and the other end of the state-of-charge sensor 100 is used to be connected to the negative-polarity terminal of the load 300. The positive electrode of the battery 200 is used to be connected to the positive-polarity terminal of the load 300. The circuit topology of the state-of-charge sensor 100 is the circuit topology of the state-of-charge sensor 100 shown in any one of the following Figure 6 , Figure 8 , Figure 13 , Figures 16 to 19 figures.

[0173] Referring to Figure 4, embodiments of the present application further provide an energy storage converter 500. The energy storage converter 500 includes a power conversion circuit 510 and a state of charge sensor 100 for the battery. The AC terminal of the power conversion circuit 510 is used to connect to the power grid 600. One end of the state of charge sensor 100 for the battery is connected to the positive DC terminal of the power conversion circuit 510, and the other end of the state of charge sensor 100 for the battery is used to connect to the positive electrode of the energy storage device 400. The negative DC terminal of the power conversion circuit 510 is used to connect to the negative electrode of the energy storage device 400. Alternatively, one end of the state of charge sensor 100 for the battery is connected to the negative DC terminal of the power conversion circuit 510, and the other end of the state of charge sensor 100 for the battery is used to connect to the negative electrode of the energy storage device 400. The positive DC terminal of the power conversion circuit 510 is used to connect to the positive electrode of the energy storage device 400. The state of charge sensor 100 for the battery is used to calculate the state of charge of the energy storage device 400, and the circuit topology of the state of charge sensor 100 for the battery is the circuit topology of the state of charge sensor 100 for the battery shown in any one of the following Figure 6 , Figure 8 , Figure 13 , Figures 16 to 19 figures.

[0174] Referring to Figure 5 , embodiments of the present application further provide an energy storage system 700. The energy storage system 700 includes an energy storage device 400 and an energy storage converter 500 connected to the energy storage device 400. The energy storage converter 500 is used to perform power conversion on the direct current output by the energy storage device 400. In embodiments of the present application, the circuit topology of the energy storage device 400 is the circuit topology of the energy storage device 400 shown in Figure 3 , and the circuit topology of the energy storage converter 500 is the circuit topology of the energy storage converter 500 shown in Figure 4 as an example for illustrative description.

[0175] The above detailed description of the state of charge sensor 100 for the battery and the analysis of beneficial effects can all be correspondingly cited in the energy storage device 400, the energy storage converter 500, and the energy storage system 700. Embodiments of the present application will not repeat them here.

[0176] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An energy storage device, characterized in that, The energy storage device includes a battery and a state of charge sensor for the battery. The state of charge sensor for the battery includes a controller, a charge and discharge circuit, an energy storage element, a first magnetic core, at least one first drive circuit, and a first coil, a second coil, at least one third coil, and a plurality of magnetic sensors coupled to the first magnetic core. There is a linear correspondence between the terminal voltage and the state of charge of the energy storage element; One end of the first coil is connected to the positive electrode of the battery, and the other end of the first coil is used to connect to the positive polarity terminal of the load. Alternatively, one end of the first coil is connected to the negative electrode of the battery, and the other end of the first coil is used to connect to the negative polarity terminal of the load; At least one first output terminal of the controller is respectively connected to the input terminals of the at least one first drive circuit. Two output terminals of each first drive circuit are connected to both ends of one of the third coils. The output terminals of the plurality of magnetic sensors are respectively connected to a plurality of first input terminals of the controller. A second output terminal of the controller is connected to a first controlled terminal of the charge and discharge circuit. The input and output terminals of the charge and discharge circuit are connected to the first end of the second coil. The second end of the second coil is connected to the first end of the energy storage element. The second end of the energy storage element is used to connect to a ground terminal. The charge and discharge circuit is used to charge or discharge the second coil; The controller is configured to calculate the state of charge of the battery according to the voltage change amount of the energy storage element.

2. The energy storage device according to claim 1, wherein The controller is configured to respectively send respective corresponding first AC excitation signals to the at least one first drive circuit; The controller is further configured to, when the effective value of the voltage across the magnetic sensor is less than or equal to a first voltage threshold, and the induced current in the magnetic sensor has an unsaturated characteristic at the positive peak value of the corresponding first AC excitation signal and a saturated characteristic at the negative peak value of the corresponding first AC excitation signal, control the charge and discharge circuit to discharge the second coil; The controller is further configured to, when the effective value of the voltage across the magnetic sensor is less than or equal to the first voltage threshold, and the induced current in the magnetic sensor has a saturated characteristic at the positive peak value of the corresponding first AC excitation signal and an unsaturated characteristic at the negative peak value of the corresponding first AC excitation signal, control the charge and discharge circuit to charge the second coil; The controller is further configured to, after controlling the charge and discharge circuit to discharge the second coil, or after controlling the charge and discharge circuit to charge the second coil, when the effective value of the voltage across the magnetic sensor is greater than the first voltage threshold, control the charge and discharge circuit to stop discharging or charging the second coil; The controller is further configured to, when the effective value of the voltage across each of the plurality of magnetic sensors is greater than its respective corresponding first voltage threshold, detect the voltage change amount of the energy storage element within a preset time and calculate the state of charge of the battery.

3. The energy storage device according to claim 2, wherein The charging and discharging energy circuit includes a first switching tube, a second switching tube and a plurality of switches, as well as a first inductor and a plurality of second inductors connected in series; The third output terminal of the controller is connected to the second controlled terminal of the charging and discharging energy circuit, the controlled terminal of the first switching tube is connected to the first controlled terminal of the charging and discharging energy circuit, the controlled terminal of the second switching tube is connected to the second controlled terminal of the charging and discharging energy circuit, the first end of the first switching tube is used to receive a positive reference voltage, the first end of the second switching tube is used to receive a negative reference voltage, the second end of the first switching tube and the second end of the second switching tube are connected, and the first inductor and the plurality of second inductors are connected between the second end of the first switching tube and the input / output terminal of the charging and discharging energy circuit, and the plurality of switches are respectively connected in parallel with the plurality of second inductors.

4. The energy storage device according to any one of claims 1-3, characterized in that The first magnetic core includes a plurality of sub-magnetic cores, the at least one first driving circuit includes a plurality of first driving circuits, the at least one third coil includes a plurality of third coils, the plurality of third coils are respectively wound around the plurality of sub-magnetic cores, the plurality of magnetic sensors are respectively coupled to the plurality of sub-magnetic cores, and the first coil and the second coil are both wound around the plurality of sub-magnetic cores in sequence; In the case where the plurality of sub-magnetic cores are respectively saturated, the absolute value of the difference between the ampere-turns of the first coil and the ampere-turns of the second coil in the plurality of sub-magnetic cores increases in sequence.

5. The energy storage device according to any one of claims 1-3, characterized in that, The first magnetic core includes a first magnetic column and a plurality of second magnetic columns arranged in sequence, the at least one first driving circuit includes one first driving circuit, and the at least one third coil includes one third coil; The first coil, the second coil and the third coil are all wound around the first magnetic column, and the plurality of magnetic sensors are respectively coupled to the plurality of second magnetic columns; Along the direction away from the first magnetic column, in the case where the plurality of second magnetic columns are respectively saturated, the absolute value of the difference between the ampere-turns of the corresponding first coil and the ampere-turns of the second coil increases in sequence.

6. The energy storage device according to claim 5, wherein The state of charge sensor of the battery further includes a second driving circuit, a second magnetic core, a fourth coil and a fifth coil, as well as a capacitor and a resistor connected in series, the second magnetic core is coupled to the first magnetic core, and the second magnetic core has the same material as the first magnetic core, the fourth coil and the fifth coil are coupled to the second magnetic core, the fourth output terminal of the controller is connected to the input terminal of the second driving circuit, two output terminals of the second driving circuit are connected to the two ends of the fourth coil, and the capacitor and the resistor are connected between the two ends of the fifth coil.

7. The energy storage device according to claim 6, wherein The controller is configured to send a second AC excitation signal to the second driving circuit, and the peak-to-valley value of the second AC excitation signal is less than or equal to the peak-to-valley value threshold; The controller is further configured to, after sending the second AC excitation signal to the second drive circuit, when the total harmonic distortion of the current in the fifth coil based on the frequency of the second AC excitation signal is greater than a total harmonic distortion threshold, send a third AC excitation signal to the second drive circuit, where the peak-to-valley value of the third AC excitation signal is equal to the peak-to-valley value of the second AC excitation signal, and the frequency of the third AC excitation signal is equal to the resonance frequency of the capacitor and the fifth coil; The controller is further configured to gradually increase the peak-to-valley value of the third AC excitation signal after sending the third AC excitation signal to the second drive circuit; The controller is further configured to stop increasing the peak-to-valley value of the third AC excitation signal and send a fourth AC excitation signal to the first drive circuit when the effective value of the voltage across the fifth coil is less than or equal to a second voltage threshold, where the peak-to-valley value of the fourth AC excitation signal is equal to the increased peak-to-valley value of the third AC excitation signal.

8. The energy storage device according to claim 7, wherein The controller is further configured to send the second AC excitation signal to the second drive circuit after sending the fourth AC excitation signal to the first drive circuit and after a preset time threshold has elapsed.

9. The energy storage device according to any one of claims 1-8, characterized in that The state of charge sensor of the battery further includes a current sensor, one end of the current sensor is connected to the second end of the energy storage element, the other end of the current sensor is configured to be connected to the ground terminal, and the output end of the current sensor is connected to the second input terminal of the controller.

10. The energy storage device according to any one of claims 1-8, characterized in that, The state of charge sensor of the battery further includes a current sensor and a second operational amplifier, one end of the current sensor is connected to the second end of the second coil, the other end of the current sensor is configured to be connected to the ground terminal, the output end of the current sensor is connected to the input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the first end of the energy storage element.

11. A state of charge sensor for a battery, characterized in that, The state of charge sensor of the battery includes a controller, an energy charging and discharging circuit, an energy storage element, a first magnetic core, at least one first drive circuit, and a first coil, a second coil, at least one third coil, and a plurality of magnetic sensors coupled to the first magnetic core, where there is a linear correspondence between the terminal voltage and the state of charge of the energy storage element; The first coil is configured to be connected between the positive electrode of the battery and the positive-polarity terminal of the load, or the first coil is configured to be connected between the negative electrode of the battery and the negative-polarity terminal of the load; At least one first output terminal of the controller is respectively connected to the input terminals of the at least one first driving circuit. Two output terminals of each first driving circuit are connected to both ends of one of the third coils. Output terminals of the plurality of magnetic sensors are respectively connected to a plurality of first input terminals of the controller. A second output terminal of the controller is connected to a first controlled terminal of the charge and discharge circuit. An input-output terminal of the charge and discharge circuit is connected to a first end of the second coil. A second end of the second coil is connected to a first end of the energy storage element. A second end of the energy storage element is used to be connected to a ground terminal. The charge and discharge circuit is configured to charge or discharge the second coil; The controller is configured to calculate a state of charge of the battery according to a voltage change amount of the energy storage element.

12. The state of charge sensor of the battery according to claim 11, wherein The controller is configured to respectively send respective corresponding first AC excitation signals to the at least one first driving circuit; The controller is further configured to control the charge and discharge circuit to discharge the second coil when an effective value of a voltage across the magnetic sensor is less than or equal to a first voltage threshold, and an induced current in the magnetic sensor has an unsaturated characteristic at a positive peak of the corresponding first AC excitation signal and a saturated characteristic at a negative peak of the corresponding first AC excitation signal; The controller is further configured to control the charge and discharge circuit to charge the second coil when an effective value of a voltage across the magnetic sensor is less than or equal to the first voltage threshold, and the induced current in the magnetic sensor has a saturated characteristic at a positive peak of the corresponding first AC excitation signal and an unsaturated characteristic at a negative peak of the corresponding first AC excitation signal; The controller is further configured to control the charge and discharge circuit to stop discharging or charging the second coil when, after controlling the charge and discharge circuit to discharge the second coil, or after controlling the charge and discharge circuit to charge the second coil, the effective value of the voltage across the magnetic sensor is greater than the first voltage threshold; The controller is further configured to detect a voltage change amount of the energy storage element within a preset time and calculate the state of charge of the battery when the effective value of the voltage across each of the plurality of magnetic sensors is greater than its respective corresponding first voltage threshold; 13. The state-of-charge sensor of the battery according to claim 11 or 12, characterized in that, The charge and discharge circuit includes a first switching tube, a second switching tube and a plurality of switches, and a first inductor and a plurality of second inductors connected in series; The third output terminal of the controller is connected to the second controlled terminal of the energy charging and discharging circuit. The controlled terminal of the first switching tube is connected to the first controlled terminal of the energy charging and discharging circuit. The controlled terminal of the second switching tube is connected to the second controlled terminal of the energy charging and discharging circuit. The first end of the first switching tube is used to receive a positive reference voltage. The first end of the second switching tube is used to receive a negative reference voltage. The second ends of the first switching tube and the second switching tube are connected. The first inductor and the plurality of second inductors are connected between the second end of the first switching tube and the input / output terminal of the energy charging and discharging circuit. The plurality of switches are respectively connected in parallel with the plurality of second inductors.

14. The state-of-charge sensor for a battery according to any one of claims 11-13, characterized in that, The first magnetic core includes a plurality of sub-magnetic cores. The at least one first driving circuit includes a plurality of first driving circuits. The at least one third coil includes a plurality of third coils. The plurality of third coils are respectively wound around the plurality of sub-magnetic cores. The plurality of magnetic sensors are respectively coupled to the plurality of sub-magnetic cores. The first coil and the second coil are both wound around the plurality of sub-magnetic cores in sequence; In the case where the plurality of sub-magnetic cores are respectively saturated, the absolute value of the difference between the ampere-turns of the first coil and the ampere-turns of the second coil in the plurality of sub-magnetic cores increases sequentially.

15. The state-of-charge sensor of the battery according to any one of claims 11-13, characterized in that The first magnetic core includes a first magnetic column and a plurality of second magnetic columns arranged in sequence. The at least one first driving circuit includes one first driving circuit. The at least one third coil includes one third coil; The first coil, the second coil, and the third coil are all wound around the first magnetic column. The plurality of magnetic sensors are respectively coupled to the plurality of second magnetic columns; Along the direction away from the first magnetic column, in the case where the plurality of second magnetic columns are respectively saturated, the absolute value of the difference between the ampere-turns of the corresponding first coil and the ampere-turns of the second coil increases sequentially.

16. The state-of-charge sensor for a battery according to claim 15, wherein The state of charge sensor of the battery further includes a second driving circuit, a second magnetic core, a fourth coil, and a fifth coil, as well as a capacitor and a resistor connected in series. The second magnetic core is coupled to the first magnetic core, and the second magnetic core has the same material as the first magnetic core. The fourth coil and the fifth coil are coupled to the second magnetic core. The fourth output terminal of the controller is connected to the input terminal of the second driving circuit. The two output terminals of the second driving circuit are connected to the two ends of the fourth coil. The capacitor and the resistor are connected between the two ends of the fifth coil.

17. The state of charge sensor of the battery according to claim 16, wherein The controller is configured to send a second AC excitation signal to the second driving circuit, and the peak-to-valley value of the second AC excitation signal is less than or equal to the peak-to-valley value threshold; The controller is further configured to, after sending the second AC excitation signal to the second drive circuit, when the total harmonic distortion of the current in the fifth coil with the frequency of the second AC excitation signal as the fundamental wave is greater than a total harmonic distortion threshold, send a third AC excitation signal to the second drive circuit, where the peak-to-valley value of the third AC excitation signal is equal to the peak-to-valley value of the second AC excitation signal, and the frequency of the third AC excitation signal is equal to the resonance frequency of the capacitor and the fifth coil; The controller is further configured to, after sending the third AC excitation signal to the second drive circuit, gradually increase the peak-to-valley value of the third AC excitation signal; The controller is further configured to, when the effective value of the voltage across the fifth coil is less than or equal to a second voltage threshold, stop increasing the peak-to-valley value of the third AC excitation signal and send a fourth AC excitation signal to the first drive circuit, where the peak-to-valley value of the fourth AC excitation signal is equal to the increased peak-to-valley value of the third AC excitation signal.

18. The state of charge sensor of the battery according to claim 17, wherein The controller is further configured to, after sending the fourth AC excitation signal to the first drive circuit and after a preset time threshold, send the second AC excitation signal to the second drive circuit.

19. A energy storage converter, characterized in that, The energy storage converter includes a power conversion circuit and a state of charge sensor of the battery, and the AC side of the power conversion circuit is used to connect to the power grid; One end of the state of charge sensor of the battery is connected to the positive DC terminal of the power conversion circuit, the other end of the state of charge sensor of the battery is used to connect to the positive electrode of the energy storage device, and the negative DC terminal of the power conversion circuit is used to connect to the negative electrode of the energy storage device; or One end of the state of charge sensor of the battery is connected to the negative DC terminal of the power conversion circuit, the other end of the state of charge sensor of the battery is used to connect to the negative electrode of the energy storage device, and the positive DC terminal of the power conversion circuit is used to connect to the positive electrode of the energy storage device; The state of charge sensor of the battery is used to calculate the state of charge of the energy storage device, and the state of charge sensor of the battery is the state of charge sensor of the battery according to any one of claims 11-18.

20. A energy storage system, characterized in that, The energy storage system includes an energy storage device and an energy storage converter connected to the energy storage device. The energy storage converter is used to perform power conversion on the direct current output by the energy storage device. The energy storage device is the energy storage device according to any one of claims 1-10, or the energy storage converter is the energy storage converter according to claim 19.

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