Current detection circuit for energy storage device and energy storage device

Abstract

The present application discloses a current detection circuit for an energy storage device and an energy storage device. The energy storage device includes a battery pack, a battery management module, an inverter and other charge and discharge modules arranged on the power supply circuit of the battery management module, and the current detection circuit includes a first sampling module, a second sampling module, a first operational amplifier unit and a second operational amplifier unit. The first sampling module is arranged in the power supply circuit; one end of the second sampling module is connected to the power supply circuit, and the other end is connected to other charge and discharge modules; the first operational amplifier unit is connected to the first sampling module to collect the first current of the first sampling module; the second operational amplifier unit is connected to the second sampling module to collect the second current of the second sampling module; the third operational amplifier unit of the inverter is connected to the first operational amplifier unit and the second operational amplifier unit to collect the charge and discharge current of the inverter. Indirect detection of the charge and discharge current of the inverter is achieved, thereby eliminating the sampling module of the inverter with higher power, which can reduce the cost and power consumption of the energy storage device.

Description

Technical Field

[0001] The present application belongs to the technical field of current detection of energy storage devices, and in particular relates to a current detection circuit of an energy storage device and an energy storage device. Background Art

[0002] With the development of society and the improvement of people's living standards, mobile energy storage now just meets people's needs for short-distance travel. Mobile energy storage is becoming more and more popular, and the market demand for refined mobile energy storage products is becoming more and more obvious.

[0003] Due to volume limitations, mobile energy storage can generally provide limited power. Therefore, minimizing unnecessary power loss is one of the important means to improve energy storage equipment. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a current detection circuit for an energy storage device and an energy storage device. By combining an operational amplifier unit with a sampling module provided in a battery management module and other charging and discharging modules, the circuit achieves indirect detection of the inverter's charge and discharge current, thereby eliminating the sampling module of the higher-power inverter and reducing the cost and power consumption of the energy storage device.

[0005] In a first aspect, the present application provides a current detection circuit for an energy storage device, the energy storage device comprising a battery pack, a battery management module connected to the battery pack, an inverter and other charging and discharging modules provided on a power supply circuit of the battery management module, the current detection circuit comprising:

[0006] a first sampling module, wherein the first sampling module is arranged in the power supply circuit;

[0007] a second sampling module, one end of which is connected to the power supply circuit, and the other end of which is connected to the other charging and discharging modules;

[0008] a first operational amplifier unit, wherein the first operational amplifier unit is connected to the first sampling module to collect a first current of the first sampling module;

[0009] a second operational amplifier unit, the second operational amplifier unit being connected to the second sampling module to collect a second current of the second sampling module;

[0010] The third operational amplifier unit of the inverter is connected to the first operational amplifier unit and the second operational amplifier unit to collect the charging and discharging current of the inverter.

[0011] In a second aspect, the present application provides an energy storage device, which includes a battery pack, a battery management module connected to the battery pack, an inverter arranged on the power supply circuit of the battery management module, other charging and discharging modules and a current detection circuit of any of the above embodiments.

[0012] The current detection circuit and energy storage device provided in the embodiment of the present application realize the detection of the charge and discharge current of the battery management module by setting a first sampling module and a first operational amplifier unit connected to the first sampling module in the power supply circuit of the battery management module. By setting a second sampling module on the power supply line flowing into each other charge and discharge module, and cooperating with the second operational amplifier unit connected to the second sampling module, the total charge and discharge current of the other charge and discharge modules can be detected. The sum of the charge and discharge current of the inverter and the total charge and discharge current of the other charge and discharge modules is the charge and discharge current of the battery management module. Therefore, by connecting the third operational amplifier unit of the inverter to the first operational amplifier unit and the second operational amplifier unit, the charge and discharge current of the inverter can be detected.

[0013] Compared to the higher power inverter, the sampling module that samples the inverter current also has higher power requirements. The other charging and discharging modules used by the second sampling module for sampling generally have lower power, so the power requirements of the second sampling module are also lower. When the energy storage device is operating, the power consumption of the lower-power second sampling module is also lower. Furthermore, the lower-power sampling module is also less expensive than the higher-power sampling module. Thus, the current detection circuit of the present application can achieve inverter charge and discharge current detection at lower cost and power consumption.

[0014] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] Figure 1 This is a schematic diagram of an application scenario of an energy storage device provided in certain embodiments of the present application;

[0017] Figure 2 is a schematic structural diagram of an energy storage device provided in certain embodiments of the present application; and

[0018] Figure 3 This is a schematic diagram of the circuit structure of the current detection circuit in the energy storage device provided in certain embodiments of the present application. DETAILED DESCRIPTION

[0019] The following further describes the embodiments of the present application in conjunction with the accompanying drawings. The same or similar reference numerals in the accompanying drawings represent the same or similar elements or elements with the same or similar functions.

[0020] In addition, the embodiments of the present application described below in conjunction with the accompanying drawings are exemplary and are only used to explain the embodiments of the present application and should not be understood as limiting the present application.

[0021] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0022] See also Figure 1 , the application scenario provided in this application includes an energy storage device 100, a terminal 200 and a cloud 300.

[0023] The terminal 200 can directly establish a communication connection with the energy storage device 100, or access the cloud 300 through the network, and then indirectly achieve a wireless connection with the energy storage device 100 connected to the cloud 300 through the cloud 300. The cloud 300 and the energy storage device 100 can communicate through the MQTT protocol (Message Queuing Telemetry Transport). MQTT is a lightweight communication protocol based on the publish / subscribe model, which is particularly suitable for use in devices with limited resources and under low bandwidth, high latency or unreliable network conditions.

[0024] Optionally, the terminal 200 also directly establishes a communication connection with the energy storage device 100 by wireless communication or wired communication, and the wireless connection includes Bluetooth communication, ZigBee communication or infrared communication.

[0025] Bluetooth and ZigBee require a connection to be established before communication can proceed. Infrared communication only requires the terminal 200 to be equipped with an infrared transmitter and the energy storage device 100 to be equipped with an infrared receiver. The terminal 200 transmits modulated infrared light, which the energy storage device 100 then demodulates to receive the control instructions sent by the terminal 200. This allows the operation of the energy storage device 100 to be controlled without establishing a communication connection.

[0026] The terminal 200 may include but is not limited to: smart phones (such as Android phones, IOS phones, etc.), tablet computers, laptops, desktop computers, smart speakers, smart watches, portable personal computers, mobile Internet devices (Mobile Internet Devices, referred to as MID), intelligent voice interaction devices, smart home appliances, vehicle terminals, aircraft, wearable devices, etc., and the embodiments of the present application do not limit this.

[0027] The energy storage device 100 is a device that can store power. It is generally provided with a rechargeable battery. The battery in the energy storage device stores a large amount of power. When needed, the energy storage device outputs the power stored in the battery for use.

[0028] The energy storage device 100 may include multiple battery packs, such as a main pack (ie, a main battery pack) and a booster pack. The booster pack may be connected to the energy storage device 100 to increase the power of the energy storage device 100.

[0029] The cloud 300 can communicate with the energy storage device 100 to implement functions such as software upgrade, control, and information storage of the energy storage device 100.

[0030] The cloud 300 may be a server. The server may be an independent physical server, or a server cluster or distributed system composed of multiple physical servers. The server may also be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms, but the embodiments of the present application do not limit this.

[0031] See also Figure 2 and Figure 3 Based on the introduction of the above-mentioned related scenarios, an embodiment of the present application provides a current detection circuit 10 of an energy storage device 100.

[0032] The energy storage device 100 includes a battery pack 20 , a battery management module 30 connected to the battery pack 20 , an inverter 40 provided on a power supply circuit of the battery management module 30 , and other charging and discharging modules 50 .

[0033] The current detection circuit 10 includes a first sampling module 11, a second sampling module 12, a first operational amplifier unit 13, and a second operational amplifier unit 14. The first sampling module 11 is arranged in the power supply circuit; one end of the second sampling module 12 is connected to the power supply circuit, and the other end is connected to the other charging and discharging module 50; the first operational amplifier unit 13 is connected to the first sampling module 11 to collect the first current of the first sampling module 11; the second operational amplifier unit 14 is connected to the second sampling module 12 to collect the second current of the second sampling module 12; and the third operational amplifier unit 41 of the inverter 40 is connected to the first operational amplifier unit 13 and the second operational amplifier unit 14 to collect the charging and discharging current of the inverter 40.

[0034] The first sampling module 11, in conjunction with the first operational amplifier unit 13, detects the charge and discharge currents of the battery management module 30. The second sampling module 12, in conjunction with the second operational amplifier unit 14, detects the charge and discharge currents of the other charge and discharge modules 50. Based on the relationship that the sum of the charge and discharge currents of the inverter 40 and the charge and discharge currents of the other charge and discharge modules 50 equals the charge and discharge current of the battery management module 30, the charge and discharge currents of the inverter 40 are detected by the third operational amplifier unit 41 of the inverter 40.

[0035] The current detection circuit 10 of the energy storage device 100 provided in the embodiment of the present application realizes the detection of the charge and discharge current of the battery management module 30 by setting a first sampling module 11 and a first operational amplifier unit 13 connected to the first sampling module 11 in the power supply circuit of the battery management module 30. By setting a second sampling module 12 on the power supply line flowing into each other charge and discharge module, and cooperating with a second operational amplifier unit 14 connected to the second sampling module 12, the total charge and discharge current of the other charge and discharge modules 50 can be detected. The charge and discharge current of the inverter 40 and the total charge and discharge current of the other charge and discharge modules 50 are added together to form the charge and discharge current of the battery management module 30. Therefore, by connecting the third operational amplifier unit 41 of the inverter 40 to the first operational amplifier unit 13 and the second operational amplifier unit 14, the charge and discharge current of the inverter 40 can be detected.

[0036] Compared to the higher power of the inverter 40 and the higher power requirements of the sampling module for sampling the current of the inverter 40, the other charging and discharging modules 50 used by the second sampling module 12 for sampling generally have lower power. Therefore, the power requirements of the second sampling module 12 are also lower. When the energy storage device 100 is operating, the power consumption caused by the lower-power second sampling module 12 is also lower. Moreover, the cost of the lower-power sampling module is also lower than that of the higher-power sampling module. In this way, the current detection circuit 10 of the present application can realize the charge and discharge current detection of the inverter 40 at a lower cost and power consumption.

[0037] Please continue reading Figure 2 and Figure 3, the energy storage device 100 of the present application is explained in detail below:

[0038] The energy storage device 100 includes a battery pack 20 , a battery management module 30 connected to the battery pack 20 , an inverter 40 arranged on a power supply circuit of the battery management module 30 , other charging and discharging modules 50 and a current detection circuit 10 .

[0039] The battery pack 20 is a device that provides electrical energy. The battery pack 20 may include one or more battery cells. The positive and negative electrodes of the battery pack 20 are connected to the battery management module 30 to provide power to the battery management module 30.

[0040] Optionally, the plurality of battery cells in the battery pack 20 may be connected together in series, in parallel, or in a combination of series and parallel.

[0041] The battery management module 30 is a module that manages the power supply of the battery pack 20. For example, the battery management module 30 may be a component equipped with a battery management system (BMS).

[0042] The battery management system (BMM) is used to monitor and control the performance of the battery pack 20, ensuring safe and efficient operation of the batteries. The BMM is generally responsible for various monitoring and control tasks within the battery pack 20 to ensure the reliability and service life of the battery pack 20.

[0043] A BMS typically has functions such as voltage monitoring and current monitoring. Voltage monitoring: This monitors the voltage of each cell in the battery pack 20 to ensure that all cells operate within a safe voltage range. Current monitoring: This measures the charge and discharge current of the battery pack 20 to prevent overcurrent and ensure that the current does not exceed the battery's safe range.

[0044] Therefore, BMS generally needs to set up corresponding sampling modules to realize the collection of electrical parameters (such as voltage and current).

[0045] The battery management module 30 includes a positive pole and a negative pole, and the loop between the positive pole and the negative pole forms a power supply loop. The battery pack 20 supplies power to the outside through the battery management module 30, which not only improves the power supply safety of the battery pack 20, but also the battery management module 30 can adjust the power supply voltage, current, etc. according to the needs of the power load, thereby achieving more flexible power supply control.

[0046] Inverter 40 is a power electronic device used to convert direct current (DC) into alternating current (AC). Inverter 40 has a wide range of applications, including renewable energy systems, uninterruptible power supplies (UPS), electric vehicle charging stations, and household appliances.

[0047] The inverter 40 is provided on the power supply circuit of the battery management module 30 , and the battery management module 30 supplies power to the inverter 40 .

[0048] Optionally, the inverter 40 includes a unidirectional inverter 40 that converts the DC power of the battery pack 20 into AC power for output. The inverter 40 also includes a bidirectional inverter 40 that, in addition to converting the DC power of the battery pack 20 into AC power for output, can also convert external AC power into DC power to charge the battery pack 20.

[0049] The core component of the inverter 40 is the switching element, which is usually a semiconductor device such as a transistor or a field effect transistor (MOSFET). These switching elements perform high-speed switching operations according to a preset control signal, thereby converting direct current into alternating current.

[0050] High-speed switching operations based on preset control signals mainly include the following methods:

[0051] (1) Pulse Width Modulation (PWM): One of the most commonly used control methods, it controls the amplitude of the output voltage by adjusting the on-time of the switching element.

[0052] (2) Sine wave modulation: used to generate high-quality sinusoidal wave output, usually using complex modulation technology.

[0053] When the inverter 40 implements AC / DC conversion, it adjusts the duty cycle of the control signal based on the input current and the current to be output. Therefore, the inverter 40 needs to detect its input current.

[0054] In conventional solutions, a sampling module is generally set directly on the input line of the inverter 40 to collect the input current. However, since the power of the inverter 40 is generally large, in the energy storage device 100, the charging and discharging current of the inverter 40 even accounts for 65% to 85% of the charging and discharging current of the battery management module 30. This means that in order to realize the current detection of the inverter 40, the power requirement of the set sampling module is also large. The greater the power of the sampling module, the greater the power consumption and the greater the cost. However, this part of the power consumption does not directly affect the user's power load and is unnecessary power consumption, thereby reducing the available power of the energy storage device 100.

[0055] Therefore, how to avoid setting up a sampling module in the inverter 40 and implement current sampling of the inverter 40 becomes a technical solution required to reduce the cost and power consumption of the energy storage device 100.

[0056] Other charging and discharging modules 50 refer to other devices used for charging or discharging in the energy storage device 100 .

[0057] For example, the other charging and discharging modules 50 may include photovoltaic panels that are connected to the power supply circuit of the battery management module 30 to charge the battery pack 20. For another example, the other charging and discharging modules 50 include functional components such as the display screen and indicator lights of the energy storage device 100, as well as the charging and discharging interfaces of the battery management module 30 (such as a USB output interface, a DC charging interface, a car charger interface, etc.).

[0058] The other charge and discharge modules 50 generally have lower power, and the total charge and discharge current of the other charge and discharge modules 50 plus the charge and discharge current of the inverter 40 equals the charge and discharge current of the battery management module 30. Therefore, to avoid directly detecting the charge and discharge current of the inverter 40, the charge and discharge current of the inverter 40 can be indirectly detected by separately detecting the charge and discharge current of the battery management module 30 and the total charge and discharge current of the other charge and discharge modules 50.

[0059] The sampling module of the battery management module 30 must be set up. Therefore, it is only necessary to set up the sampling module on the input line of other charging and discharging modules 50, so that the low-power sampling module set on the input line of other charging and discharging modules 50 can be used to replace the high-power sampling module on the input line of the inverter 40. While realizing indirect sampling of the charging and discharging current of the inverter 40, the cost and power consumption of current sampling are reduced.

[0060] The current detection circuit 10 for indirectly sampling the charging and discharging current of the inverter 40 is described in detail below:

[0061] See also Figure 3 The current detection circuit 10 includes a first sampling module 11 (such as Figure 3 R1 in), the second sampling module 12 (such as Figure 3 R2 in), the first operational amplifier unit 13 (such as Figure 3 OP1 in) and the second operational amplifier unit 14 (such as Figure 3 OP2 in the ).

[0062] In some embodiments, the first sampling module 11 can be placed in the power supply circuit and needs to be placed close to the battery management module 30. In other words, the supply current of the battery management module 30 first passes through the first sampling module 11 before entering other modules of the energy storage device 100; the charging current enters the battery management module 30 after passing through the first sampling module 11.

[0063] In this way, it can be ensured that the first sampling module 11 can accurately detect the charge and discharge current (ie, the first current) of the battery management module 30 .

[0064] Optionally, the first sampling module 11 may include one or more first sampling resistors (Sampling Resistor), and the one or more sampling resistors are connected together to meet the power requirement of the current sampling of the battery management module 30.

[0065] Sampling resistors are a common technique for measuring current. They indirectly measure the current flowing through a known resistor by placing it in a circuit and measuring the voltage drop across it. This technique is widely used in various applications, such as current sensing, power monitoring, and overcurrent protection.

[0066] In some embodiments, one end of the second sampling module 12 is connected to the power supply circuit, and the other end is connected to the other charging and discharging modules 50. In other words, the current from the power supply circuit must first pass through the second sampling module 12 before entering the other charging and discharging modules 50. The charging currents from the other charging and discharging modules 50 are then combined and passed through the second sampling module 12.

[0067] In this way, it is ensured that the second sampling module 12 can accurately detect the total charge and discharge current (ie, the second current) of the other charge and discharge modules 50 .

[0068] Optionally, the second sampling module 12 may include one or more second sampling resistors (Sampling Resistor), and the one or more sampling resistors are connected together to meet the power requirement of current sampling of other charging and discharging modules 50.

[0069] In some embodiments, the first operational amplifier unit 13 is connected to the first sampling module 11 to collect the first current of the first sampling module 11. Specifically, the two input terminals of the first operational amplifier unit 13 are respectively connected to the two ends of the first sampling module 11, so that the first current is determined by sampling the voltages at the two ends of the first sampling module 11 in combination with the resistance of the first sampling module 11.

[0070] Optionally, the first operational amplifier unit 13 includes a subtractor. After the voltages collected by the two input terminals of the first operational amplifier unit 13 pass through the subtractor, the voltage difference between the two terminals of the first sampling module 11 can be obtained, and the first current can be calculated through the voltage difference and the resistance of the first sampling module 11.

[0071] Optionally, the first operational amplifier unit 13 may further include an amplifier. It is understood that, in order to reduce the heat generated by the sampling resistor, the resistance of the sampling resistor is generally small, which results in a generally small voltage difference across the sampling resistor. However, due to sampling accuracy limitations of the analog-to-digital converter, the voltage difference between the two sampled voltages may be too small (e.g., 0), thereby failing to detect the first current.

[0072] Therefore, after the two input terminals of the first operational amplifier unit 13 sample and obtain two voltages, they will first be amplified by the amplifier and then passed through the subtractor to obtain the voltage difference between the two ends of the first sampling module 11, which can meet the sampling accuracy requirements and accurately obtain the first current.

[0073] In some embodiments, the second operational amplifier unit 14 is connected to the second sampling module 12 to collect the second current of the second sampling module 12. Specifically, the two input terminals of the second operational amplifier unit 14 are respectively connected to the two ends of the second sampling module 12, so that the second current is determined by sampling the voltage at the two ends of the second sampling module 12 in combination with the resistance of the first sampling module 11.

[0074] Optionally, the second operational amplifier unit 14 includes a subtractor. After the voltages collected by the two input terminals of the second operational amplifier unit 14 pass through the subtractor, the voltage difference between the two terminals of the second sampling module 12 can be obtained, and the second current can be calculated through the voltage difference and the resistance of the second sampling module 12.

[0075] Optionally, the second operational amplifier unit 14 may further include an amplifier. It is understood that, in order to reduce the heat generated by the sampling resistor, the resistance of the sampling resistor is generally small, which results in a small voltage difference across the sampling resistor. However, due to sampling accuracy limitations, the voltage difference between the two sampled voltages may be too small (e.g., 0), making it impossible to detect the second current.

[0076] Therefore, after the two input terminals of the second operational amplifier unit 14 sample and obtain two voltages, they will first be amplified by the amplifier and then passed through the subtractor to obtain the voltage difference between the two ends of the second sampling module 12, which can meet the sampling accuracy requirements and accurately obtain the first current.

[0077] In some embodiments, the inverter 40 is provided with a device for current sampling, specifically a third operational amplifier unit 41 (eg Figure 3 The third operational amplifier unit 41 is connected to the output end of the first operational amplifier unit 13 and the second operational amplifier unit 14 to sample and obtain the charge and discharge current of the inverter 40 based on the outputs of the first operational amplifier unit 13 and the second operational amplifier unit 14.

[0078] Optionally, two input terminals of the third operational amplifier unit 41 are connected to the output terminal of the first operational amplifier unit 13 and the output terminal of the second operational amplifier unit 14 respectively.

[0079] Optionally, the third operational amplifier unit 41 includes a subtractor. The first operational amplifier unit 13 and the second operational amplifier unit 14 respectively output the first voltage difference of the first sampling module 11 of the battery management module 30 and the second voltage difference of the second sampling module 12 of the other charge and discharge module 50. The third operational amplifier unit 41 can determine the charge and discharge current of the inverter 40 based on the difference between the first and second voltage differences.

[0080] Optionally, the voltage difference corresponding to the inverter 40 can be determined by the difference between the first voltage difference and the second voltage difference. Then, based on the equivalent resistance corresponding to the inverter 40, the charge and discharge current of the inverter 40 can be calculated.

[0081] Optionally, in order to ensure that the first sampling module 11, the second sampling module 12, and the inverter 40 have the same equivalent resistance, the amplification factor of the first operational amplifier unit 13 and the amplification factor of the second operational amplifier unit 14 need to be set to match the amplification gains of the first operational amplifier unit 13 and the second operational amplifier unit 14. In other words, the voltage difference output by the first operational amplifier unit 13 and the second operational amplifier unit 14 is obtained based on the same equivalent resistance.

[0082] For example, the resistances of the first sampling module 11 and the second sampling module 12 are 30 milliohms (mR) and 5 mR, respectively. If 5 mR is used as the equivalent resistance, the amplification factor of the second operational amplifier unit 14 needs to be 6 times that of the first operational amplifier unit 13 so that the resistances corresponding to the voltage difference between the two are the same.

[0083] In this way, after the third operational amplifier unit 41 obtains the difference between the first voltage difference and the second voltage difference, the analog-to-digital conversion module of the inverter 40 can quickly calculate the charge and discharge current of the inverter 40 based on the difference and the equivalent resistance.

[0084] An analog-to-digital converter (ADC) module is an electronic device or circuit module used to convert analog signals into digital signals. ADCs play a crucial role in modern electronic systems, especially when processing data from analog signal sources such as sensors and microphones.

[0085] The analog-to-digital conversion module is connected to the output end of the third operational amplifier unit 41 to collect the first analog signal (i.e., the difference between the first pressure difference and the second pressure difference (also a voltage signal)) at the output end of the third operational amplifier unit 41, and converts the first analog signal into a first digital signal (i.e., a voltage value). The charge and discharge current of the inverter 40 can be quickly calculated based on the voltage value and the equivalent resistance.

[0086] Optionally, the third op amp unit 41 may further include an amplifier. It is understood that, generally, to reduce the heat generated by the sampling resistor, the resistance of the sampling resistor is generally small, which results in a generally small voltage difference across the sampling resistor. However, due to the sampling accuracy limitations of the analog-to-digital converter, the voltage difference between the two sampled voltages may be too small (e.g., 0). If the first op amp unit 13 and the second op amp unit 14 are amplified by the amplifier, or if the first and second voltage differences after amplification are still small, the voltage signal received by the input of the third op amp unit 41 will still be small and may not meet the sampling accuracy requirements. Therefore, the third op amp unit 41 may also be provided with an amplifier as needed to ensure that the voltage signal before entering the subtractor meets the sampling accuracy requirements.

[0087] In some embodiments, the analog-to-digital conversion module is connected to the output end of at least one of the first operational amplifier unit 13 and the second operational amplifier unit 14 to collect the second analog signal of the output end of at least one of the first operational amplifier unit 13 and the second operational amplifier unit 14, and convert the second analog signal into a second digital signal. The charge and discharge current of the battery management module 30 is determined based on the second digital signal corresponding to the first operational amplifier unit 13, and the charge and discharge current of other charge and discharge modules 50 is determined based on the second digital signal corresponding to the second operational amplifier unit 14.

[0088] That is to say, in addition to realizing the output sampling of the third operational amplifier unit 41, the analog-to-digital conversion module of the inverter 40 can also realize the output sampling of the first operational amplifier unit 13 corresponding to the battery management module 30, thereby obtaining the charging and discharging current of the battery management module 30 based on the equivalent resistance.

[0089] Similarly, the analog-to-digital conversion module of the inverter 40 can also implement output sampling of the second operational amplifier units 14 corresponding to other charge and discharge modules 50 , thereby obtaining the total charge and discharge current of other charge and discharge modules 50 based on the equivalent resistance.

[0090] In this way, even the analog-to-digital conversion module may not be set in the battery management module 30, but the analog-to-digital conversion module of the inverter 40 may be shared. Then, by communicating with the inverter 40, the charging and discharging current of the battery management module 30 can be obtained, thereby further reducing the cost of the energy storage device 100.

[0091] In some embodiments, when the inverter 40 is not powered on, the control current detection circuit 10 stops working (for example, by disconnecting the connection between the first operational amplifier unit 13 and the first sampling module 11, and the connection between the second operational amplifier unit 14 and the second sampling module 12 through a switch); when the inverter 40 is powered on, the control current detection circuit 10 starts working.

[0092] In this way, the current detection circuit 10 works as needed, thereby avoiding unnecessary power consumption.

[0093] In order to better illustrate the effect of this application, a specific example is given below:

[0094] In one example, the power of the energy storage device 100 is 2000 watts (W), with specific specifications of a battery voltage of 48V (ie, the output voltage of the battery pack 20), an inverter 40 input power of 2400W, and an input power of 480W for other charge and discharge modules 50.

[0095] It can be obtained that the maximum output current of the battery management module 30 is: (2400W+480W) / 48V=60A, the maximum input current of the inverter 40 is: 2400W / 48V=50A, and the input current of other charging and discharging circuits is: 480W / 48V=10A.

[0096] If the detection of the charging and discharging current of the inverter 40 is implemented using a conventional solution, the configuration is as follows:

[0097] For the battery management module 30 , to implement current sampling, six sampling resistors with a power of 3W and a resistance of 5 milliohms (mR) need to be set, and the full-load working power is about 3W.

[0098] For the inverter 40 , five sampling resistors with a power of 3 W and a resistance of 5 milliohms (mR) need to be provided, and the full-load operating power is about 2.5 W.

[0099] A total of 11 sampling resistors are used, with a total power consumption of 5.5W.

[0100] If the charging and discharging current detection of the inverter 40 is implemented using the solution of the present application, the configuration is as follows:

[0101] Among them, for the battery management module 30, to implement current sampling, the first sampling module 11 needs to set 6 sampling resistors with a power of 3W and a resistance of 5 milliohms (mR). The full-load working power is about 3W, which remains unchanged.

[0102] For other charge-discharge modules 50 , the second sampling module 12 only needs to be equipped with a sampling resistor with a power of 3W and a resistance of 5 milliohms (mR), and the full-load working power is about 0.5W.

[0103] A total of 7 sampling resistors are used, with a total power consumption of 3.5W.

[0104] By comparison, it can be seen that the solution of the present application significantly reduces the number of sampling resistors, and the power consumption of the first operational amplifier unit 13 and the second operational amplifier unit 14 of the present application is essentially negligible. Therefore, when the solution of the present application implements the charge and discharge current detection of the inverter 40, the power consumption and required cost are significantly reduced. Moreover, the greater the power of the energy storage device 100, the greater the cost and power consumption reduction of the solution of the present application, which has a greater advantage.

[0105] Throughout this specification, reference to the terms "certain embodiments," "one embodiment," "some examples," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0106] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include at least one feature. In the description of this application, "plurality" means at least two, for example, two or three, unless otherwise specifically defined.

[0107] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A current detection circuit for an energy storage device, characterized in that: The energy storage device includes a battery pack, a battery management module connected to the battery pack, an inverter and other charging and discharging modules arranged on the power supply circuit of the battery management module, and the current detection circuit includes: a first sampling module, the first sampling module being arranged in the power supply circuit, and the current of the battery pack passing through the first sampling module; a second sampling module, one end of which is connected to the power supply circuit, and the other end of which is connected to the other charging and discharging modules; a first operational amplifier unit, wherein the first operational amplifier unit is connected to the first sampling module to collect a first current of the first sampling module; a second operational amplifier unit, the second operational amplifier unit being connected to the second sampling module to collect a second current of the second sampling module; a third operational amplifier unit connected to the first operational amplifier unit and the second operational amplifier unit to collect the charge and discharge current of the inverter; the first operational amplifier unit, the second operational amplifier unit, and the third operational amplifier unit all include a subtractor; the third operational amplifier unit includes two input terminals; the output terminals of the first operational amplifier unit and the second operational amplifier unit are respectively connected to the two input terminals of the third operational amplifier unit; the first operational amplifier unit outputs the first pressure difference of the battery management module collected by the first sampling module; the first operational amplifier unit outputs the second pressure difference of the other charge and discharge modules collected by the second sampling module; the third operational amplifier unit determines the charge and discharge current of the inverter based on the difference between the first and second pressure differences inputted.

2. The current detection circuit according to claim 1, wherein: The first sampling module includes a first sampling resistor, and the second sampling module includes a second sampling resistor.

3. The current detection circuit according to claim 1 or 2, characterized in that: The first operational amplifier unit and the second operational amplifier unit each include two input terminals. The two input terminals of the first operational amplifier unit are respectively connected to the two ends of the first sampling module, and the two input terminals of the second operational amplifier unit are respectively connected to the two ends of the second sampling module.

4. The current detection circuit according to claim 1, wherein: The first operational amplifier unit and the second operational amplifier unit both include amplifiers; or, the first operational amplifier unit, the second operational amplifier unit and the third operational amplifier unit both include amplifiers.

5. The current detection circuit according to claim 4, characterized in that: The amplification gains of the amplifiers of the first operational amplifier unit and the second operational amplifier unit are matched so that the outputs of the first operational amplifier unit and the second operational amplifier unit correspond to the same equivalent resistance.

6. An energy storage device, characterized in that: The energy storage device comprises: A battery pack, a battery management module connected to the battery pack, an inverter arranged on the power supply circuit of the battery management module, other charging and discharging modules and the current detection circuit according to any one of claims 1 to 5.

7. The energy storage device according to claim 6, characterized in that The battery management module, the inverter and the current detection circuit are all arranged on the same circuit board.

8. The energy storage device according to claim 6, characterized in that: The inverter also includes an analog-to-digital conversion module, which is connected to the output end of the third operational amplifier unit to collect a first analog signal from the output end of the third operational amplifier unit and convert the first analog signal into a first digital signal. The charge and discharge current of the inverter is determined based on the digital signal.

9. The energy storage device according to claim 8, characterized in that The analog-to-digital conversion module is connected to the output end of at least one of the first operational amplifier unit and the second operational amplifier unit to collect a second analog signal from the output end of at least one of the first operational amplifier unit and the second operational amplifier unit, and convert the second analog signal into a second digital signal. The charge and discharge current of the battery management module is determined based on the second digital signal corresponding to the first operational amplifier unit, and the charge and discharge current of the other charge and discharge modules is determined based on the second digital signal corresponding to the second operational amplifier unit.

10. The energy storage device according to any one of claims 6 to 9, characterized in that: When the inverter is not powered on, the current detection circuit is controlled to stop working; when the inverter is powered on, the current detection circuit is controlled to start working.

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