Current detection circuit of energy storage equipment and energy storage equipment

Abstract

The invention discloses a current detection circuit of energy storage equipment and the energy storage equipment. The energy storage device comprises a battery pack, a battery management module, an inverter arranged on a power supply loop of the battery management module and other charging and discharging modules. The current detection circuit comprises 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 a power supply loop; one end of the second sampling module is connected with the power supply loop, and the other end is connected with other charge-discharge modules; the first operational amplifier unit is connected with the first sampling module so as to collect a first current of the first sampling module; the second operational amplifier unit is connected with the second sampling module to collect a second current of the second sampling module; and a third operational amplifier unit of the inverter is connected with the first operational amplifier unit and the second operational amplifier unit so as to collect the charging and discharging current of the inverter. Indirect detection of charging and discharging current of the inverter is realized, so that a sampling module of the inverter with relatively high power is omitted, and the cost and the power consumption of energy storage equipment can be reduced.

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 detailed mobile energy storage products is becoming more and more obvious.

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

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a current detection circuit and an energy storage device, which realizes indirect detection of the charging and discharging current of the inverter by combining an operational amplifier unit with a sampling module set in a battery management module and other charging and discharging modules, thereby eliminating the sampling module of the inverter with higher power, 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 of an energy storage device, wherein 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 a power supply circuit of the battery management module, and the current detection circuit includes:

[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, wherein the second operational amplifier unit is 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 a power supply circuit of the battery management module, other charging and discharging modules, and a current detection circuit of any of the above-mentioned 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 charge and discharge current of the inverter and the total charge and discharge current of the other charge and discharge modules are added together to form 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 detection of the charge and discharge current of the inverter can be realized.

[0013] Compared with the inverter power being higher, the power requirement of the sampling module for current sampling of the inverter is also higher. The other charging and discharging modules used for sampling by the second sampling module are generally lower in power, so the power requirement of the second sampling module is also lower. When the energy storage device is running, the power consumption brought by the lower-power second sampling module is also lower. Moreover, the cost of the sampling module with lower power is also lower than that of the sampling module with higher power. In this way, the current detection circuit of the present application can realize the charging and discharging current detection of the inverter at a 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 apparent from the description below, or will be learned through the 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 It is a schematic diagram of an application scenario of an energy storage device provided in some embodiments of the present application;

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

[0018] Figure 3 It is a schematic diagram of the circuit structure of the current detection circuit in the energy storage device provided in some 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 drawings are exemplary and are only used to explain the embodiments of the present application and should not be construed as limiting the present application.

[0021] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature 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. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in 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, near field communication protocol (zigbee) communication or infrared communication.

[0025] Among them, Bluetooth connection communication (bluetooth) and near field communication protocol (zigbee) need to establish a communication connection before communication. Infrared communication only requires the terminal 200 to set up an infrared transmitter and the energy storage device 100 to set up an infrared receiver. The terminal 200 transmits modulated infrared light, and then the energy storage device 100 demodulates the infrared light to obtain the control instructions sent by the terminal 200, so that the operation control of the energy storage device 100 can be achieved without establishing a communication connection.

[0026] 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-mounted terminals, aircraft, wearable devices, etc., and the embodiments of the present application are not limited to this.

[0027] The energy storage device 100 refers to a device capable of storing power, and is generally provided with a rechargeable battery. The battery in the energy storage power supply stores a large amount of power, and when needed, the energy storage power supply outputs the electric energy stored in the battery for use.

[0028] The energy storage device 100 may include a plurality of battery packs, such as a main pack (ie, a main battery pack) and a power-up pack, which 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, or 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, etc., which is not limited in the embodiments of the present application.

[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 and other charging and discharging modules 50 arranged on a power supply circuit of the battery management module 30 .

[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 set 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 other charging and discharging modules 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; 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 is combined with the first operational amplifier unit 13 to detect the charge and discharge current of the battery management module 30. The second sampling module 12 is combined with the second operational amplifier unit 14 to detect the charge and discharge current of other charge and discharge modules 50. Then, based on the relationship that the sum of the charge and discharge current of the inverter 40 and the charge and discharge current of other charge and discharge modules 50 is equal to the charge and discharge current of the battery management module 30, the charge and discharge current of the inverter 40 is 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 detection of the total charge and discharge current of the other charge and discharge modules 50 is realized. 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 detection of the charge and discharge current of the inverter 40 can be realized.

[0036] Compared with the inverter 40, which has a higher power and a higher power requirement for the sampling module for current sampling of the inverter 40, the other charging and discharging modules 50 for sampling by the second sampling module 12 are generally lower in power, so the power requirement of the second sampling module 12 is also lower. When the energy storage device 100 is running, the power consumption brought by the lower-power second sampling module 12 is also lower. Moreover, the cost of the sampling module with lower power is also lower than that of the sampling module with higher power. 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 for providing electric 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 supply power to the battery management module 30.

[0040] Optionally, a 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 is used to monitor and control the performance of the battery pack 20 to ensure that the battery works safely and efficiently. The BMM is usually responsible for various monitoring and control tasks within the battery pack 20 to ensure the reliability of the battery pack 20 and extend its service life.

[0043] BMS generally has functions such as voltage monitoring and current monitoring: Voltage detection: monitors the voltage of each single cell in the battery pack 20 to ensure that all batteries operate within a safe voltage range. Current monitoring: measures the charge and discharge current of the battery pack 20 to prevent overcurrent and ensure that the current does not exceed the safety range of the battery.

[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 electrode and a negative electrode. The circuit between the positive electrode and the negative electrode forms a power supply circuit. 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 realizing more flexible power supply control.

[0046] The inverter 40 is a power electronic device for converting direct current (DC) into alternating current (AC). The inverter 40 is widely used in many fields, including renewable energy systems, uninterruptible power supplies (UPS), electric vehicle charging stations, home appliances, etc.

[0047] The inverter 40 is arranged 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, which converts the DC power of the battery pack 20 into AC power output. The inverter 40 also includes a bidirectional inverter 40, which can convert the DC power of the battery pack 20 into AC power output and can also convert the external input AC power into DC power to charge the battery pack 20.

[0049] The core component of the inverter 40 is a 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] The high-speed switching operation according to the preset control signal mainly includes the following methods:

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

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

[0053] When the inverter 40 realizes 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 schemes, 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 results in 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. 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 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 a photovoltaic panel, which is 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 a display screen and an indicator light of the energy storage device 100, and a charging and discharging interface (such as a USB output interface, a DC charging interface, a car charging interface, etc.) of the battery management module 30.

[0058] The other charge and discharge modules 50 generally have a relatively small 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 is equal to the charge and discharge current of the battery management module 30. Therefore, in order 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 respectively 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 the sampling module on the input line of other charging and discharging modules 50, so as to use the low-power sampling module set on the input line of other charging and discharging modules 50 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 implementing indirect sampling of 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 above).

[0062] In some embodiments, the first sampling module 11 can be set in the power supply circuit, and the first sampling module 11 needs to be set close to the battery management module 30. In other words, the power supply current of the battery management module 30 first passes through the first sampling module 11, and then enters 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 charging and discharging 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 current sampling of the battery management module 30.

[0065] Among them, sampling resistance is a technical means commonly used to measure current. It indirectly measures the current flowing through the resistor by placing a resistor of known resistance in the circuit and measuring the voltage drop across the resistor. This technology is widely used in many occasions, such as current detection, power monitoring, overcurrent protection, etc.

[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 other charging and discharging modules 50. That is to say, before the current of the power supply circuit enters other charging and discharging modules 50, it needs to pass through the second sampling module 12, and the charging current of other charging and discharging modules 50 will also pass through the second sampling module 12 after being converged.

[0067] In this way, it can be ensured that the second sampling module 12 can accurately detect the total charge and discharge current (ie, the second current) of 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 as to determine the first current by sampling the voltage at the two ends of the first sampling module 11 and combining 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, so that 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 makes the voltage difference across the sampling resistor generally small. However, due to the sampling accuracy limitation of the analog-to-digital converter, the voltage difference between the two voltages obtained by sampling may be too small (such as 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 to 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 and combining 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 ends of the second sampling module 12 can be obtained, so that 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 makes the voltage difference across the sampling resistor generally small. However, due to the sampling accuracy limitation, the voltage difference between the two voltages obtained by sampling may be too small (such as 0), thereby failing 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 to 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 (such as 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, so as to sample and obtain the charge and discharge current of the inverter 40 based on the output 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 respectively connected to the output terminal of the first operational amplifier unit 13 and the output terminal of the second operational amplifier unit 14 .

[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 charging and discharging module 50. The third operational amplifier unit 41 can determine the charging and discharging current of the inverter 40 based on the difference between the input first voltage difference and the second voltage difference.

[0080] Optionally, the voltage difference corresponding to the inverter 40 may 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 may be calculated.

[0081] Optionally, in order to make the first sampling module 11, the second sampling module 12 and the inverter 40 have the same equivalent resistance, it is necessary to set the amplification factor of the first operational amplifier unit 13 and the amplification factor of the second operational amplifier unit 14 to match the amplification gains of the amplifiers 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 taken as the equivalent resistance, the amplification factor of the second operational amplifier unit 14 needs to be 6 times the amplification factor 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] Among them, the analog-to-digital converter module (ADC module) is an electronic device or circuit module used to convert analog signals into digital signals. ADC plays a vital role in modern electronic systems, especially when it is necessary to process 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 charging and discharging current of the inverter 40 can be quickly calculated based on the voltage value and the equivalent resistance.

[0086] Optionally, the third operational amplifier unit 41 may also 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 makes the voltage difference across the sampling resistor generally small. However, due to the sampling accuracy limitation of the analog-to-digital converter, the voltage difference between the two voltages obtained by sampling may be too small (such as 0). If the first operational amplifier unit 13 and the second operational amplifier unit 14 are amplified by the amplifier, or the first voltage difference and the second voltage difference after amplification are still small, the voltage signal received by the input end of the third operational amplifier unit 41 is still small and may not meet the sampling accuracy requirements. Therefore, the third operational amplifier 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 a second analog signal from 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 implementing the output sampling of the third operational amplifier unit 41, the analog-to-digital conversion module of the inverter 40 can also implement 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 charging and discharging modules 50 , thereby obtaining the total charging and discharging current of other charging and discharging 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, and then the charging and discharging current of the battery management module 30 can be acquired by communicating with the inverter 40, 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 (such as 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 required, 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), and the specific specifications are 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 in a conventional scheme, the configuration is as follows:

[0097] Among them, for the battery management module 30, to realize current sampling, it is necessary to set 6 sampling resistors with a power of 3W and a resistance of 5 milliohms (mR), 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 set, and the full-load working 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 by 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 and discharge modules 50 , the second sampling module 12 only needs to be provided 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 basically negligible. Therefore, when the solution of the present application realizes the charge and discharge current detection of the inverter 40, the power consumption and the required cost are significantly reduced. Moreover, the greater the power of the energy storage device 100, the greater the cost and power consumption reduced by the solution of the present application, which has a greater advantage.

[0105] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some examples", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0106] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one feature. In the description of this application, the meaning of "plurality" is at least two, such as two, three, unless otherwise clearly and 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 exemplary 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 a power supply circuit of the battery management module, and the current detection circuit includes: A first sampling module, wherein the first sampling module is arranged in the power supply circuit, and the current of the battery pack passes 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, wherein the second operational amplifier unit is connected to the second sampling module to collect a second current of the second sampling module; The third operational amplifier unit is connected to the first operational amplifier unit and the second operational amplifier unit to collect the charging and discharging current of the inverter.

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

4. The current detection circuit according to claim 1, characterized in that: The first operational amplifier unit, the second operational amplifier unit and the third operational amplifier unit all include a subtractor.

5. The current detection circuit according to claim 1 or 4, characterized in that: 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 all include amplifiers.

6. The current detection circuit according to claim 5, 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.

7. The current detection circuit according to claim 4, characterized in that: The third operational amplifier unit includes two input terminals, and 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.

8. 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 7.

9. The energy storage device according to claim 8, characterized in that: The battery management module, the inverter and the current detection circuit are all arranged on the same circuit board.

10. The energy storage device according to claim 8, 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 at the output end of the third operational amplifier unit and convert the first analog signal into a first digital signal. The charging and discharging current of the inverter is determined based on the digital signal.

11. The energy storage device according to claim 10, 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.

12. The energy storage device according to any one of claims 8 to 11, 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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