A BMS auxiliary subsystem

Abstract

The utility model discloses a kind of BMS auxiliary subsystem, including auxiliary equipment, BMS and hall current sensor;The auxiliary equipment and BMS are not in common place;The hall current sensor, including isolated sampling side and power supply output side;Its sampling side is connected in the power supply main circuit of auxiliary equipment, its power supply output side is powered by BMS, the signal output end of its power supply output side and the microcontrol unit of BMS are connected, output voltage signal for characterizing the power supply main circuit current of auxiliary equipment, wherein, BMS is battery management system unit.The BMS auxiliary subsystem of the utility model introduces hall current sensor to carry out current detection, realizes the effective detection of floating ground current, with (1) high isolation and high reliability;(2) small, low in cost, high integration;(3) ac-dc compatible detection and so on Characteristics.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology of energy storage systems, and in particular to a BMS auxiliary subsystem. Background Technology

[0002] With the widespread application of energy storage systems, their safety and reliability have become increasingly important concerns. Energy storage systems typically include a main power circuit and multiple auxiliary subsystems, such as battery heating systems, fire suppression systems, water immersion detection systems, and smoke sensor systems. The control system ground and power ground of these auxiliary subsystems are not directly electrically connected. Some modules use DC power, while others use AC power to suppress common-mode interference, improve noise immunity, or meet safety isolation requirements. However, the lack of effective current monitoring methods leads to the inability to identify abnormal conditions in a timely manner.

[0003] Most existing products on the market have auxiliary subsystems that are not grounded, and they do not monitor the current of the floating ground circuit in real time. The control system cannot know whether the heater has actually started, whether the fire pump is working properly, or whether the sensor power supply is connected. The lack of effective current monitoring means that abnormal conditions cannot be identified in time. For example, in the event of a fire, the inability to confirm the operating current of the fire protection system may cause the best rescue opportunity to be missed.

[0004] Disadvantages of traditional testing methods: 1) Some products on the market use traditional current sensing solutions with current transformers in their auxiliary subsystems (such as the CT101 model), which result in large size. The drawback is high cost.

[0005] 2) Some products on the market use traditional current detection chips in their auxiliary subsystems. When the power device is disconnected during overcurrent protection, it will generate a large reverse voltage of 60-100V, and some even higher than 300V, which exceeds the 60V common mode withstand voltage limit of traditional detection chips (such as INA219).

[0006] Voltage stress surge risk: When an energy storage system experiences overcurrent, short circuit, or other faults, the protection circuit will quickly activate, disconnecting the main circuit (e.g., by disconnecting the power MOSFET or contactor). In this instant, some modules that were originally not floating may momentarily become floating due to the topology change, generating extremely high back electromotive force and common-mode voltage. This voltage far exceeds the maximum common-mode voltage tolerance of conventional current sensing chips (such as op-amp-based shunt detection schemes), easily causing damage to precision components in the sensing module (such as operational amplifiers and ADC drivers), resulting in permanent failure.

[0007] Therefore, there is an urgent need for a solution that can safely, accurately, and economically detect the floating ground loop current of the auxiliary subsystems of an energy storage system in order to improve the overall observability and safety of the system. Utility Model Content

[0008] To achieve the above objectives, this utility model provides a solution for a BMS auxiliary subsystem capable of safely, accurately, and economically detecting floating ground loop current. The technical solution is as follows: A BMS auxiliary subsystem includes an auxiliary device, a BMS, and a Hall current sensor; the auxiliary device and the BMS are not grounded; the Hall current sensor includes an isolated sampling side and a power supply output side; its sampling side is connected in series in the main power supply circuit of the auxiliary device, its power supply output side is powered by the BMS, and its signal output terminal is connected to the microcontroller unit of the BMS to output a voltage signal characterizing the current of the main power supply circuit of the auxiliary device.

[0009] Furthermore, the Hall current sensor is a linear Hall current sensor, and its output voltage signal is linearly related to the current flowing through the sampling side.

[0010] Furthermore, the Hall current sensor is integrated on the BMS printed circuit board.

[0011] Furthermore, the auxiliary device is a cell heating film; the cell heating film is connected between the positive electrode of the battery pack and a switching path, the switching path includes a semiconductor switching device and the Hall current sensor connected in series, and is connected to the negative electrode of the BMS; the control terminal of the semiconductor switching device is electrically connected to the microcontroller unit.

[0012] Furthermore, the semiconductor switching device is a MOSFET.

[0013] Furthermore, the auxiliary equipment is an AC power supply device, and the Hall current sensor is connected in series in the AC power supply circuit of the AC power supply device to collect the current on its neutral or live wire.

[0014] Furthermore, the AC power supply equipment includes an air conditioning module, a fire protection module, and a water immersion module.

[0015] Furthermore, the AC power supply equipment is connected to the BMS via RS485 communication.

[0016] Compared with the prior art, the significant features of this utility model are: The BMS auxiliary subsystem of this utility model introduces a Hall current sensor for current detection, realizing the effective detection of floating ground current. It has the characteristics of (1) high isolation and high reliability; (2) small size, low cost and high integration; and (3) AC / DC compatible detection. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the current detection circuit of the battery cell heating film of this utility model. Figure 2 This is a simplified diagram of the current detection circuit of the battery cell heating film of this utility model; Figure 3 This is a schematic diagram of the current detection circuit for the battery cell heating film of this utility model; Figure 4 This is a simplified diagram of the current detection circuit of the air conditioning module of this utility model; Figure 5 This is a simplified diagram of the current detection circuit of the fire protection module of this utility model; Figure 6 This is a simplified diagram of the current detection circuit of the water immersion module of this utility model. Detailed Implementation

[0018] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0019] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0020] like Figures 1-3 As shown, this utility model discloses a BMS auxiliary subsystem – a cell heating system. In this cell heating system, a Hall current sensor is integrated on the BMS PCB. The cell heating film and the BMS share a common positive terminal (one end of the cell heating film and the BMS's positive power supply P+ are connected to the positive terminal B+ of the battery pack). The other end of the cell heating film is connected to the negative terminal P- of the BMS via a heating MOSFET and the Hall current sensor. The signal output terminal of the Hall current sensor is connected to the BMS's microcontroller unit (MCU), sending a current sampling signal to the MCU. The MCU is connected to the gate of the heating MOSFET via an I / O pin, controlling the heating circuit's on / off state through the heating MOSFET.

[0021] In this embodiment, a high-precision Hall current sensor is used, such as the ACS712 series, ACS758 series, and CC6902 series. These devices integrate current sensing, signal conditioning, and isolation functions, and their output voltage signal is linearly related to the current flowing through the sampling side. The Hall current sensor includes an electrically isolated current acquisition side and a power output side. The current acquisition side includes a positive current acquisition terminal IP+ and a negative current acquisition terminal IP-. The power supply is connected to the negative terminal P- of the BMS via a heated MOSFET, a cell heating film, the positive current acquisition terminal IP+, and the negative current acquisition terminal IP-.

[0022] like Figure 3 In the circuit shown, the power supply output side of the Hall current sensor U1 and the BMS are on the same power supply network. VCC is the operating voltage of the BMS MCU, which is usually 3.3V or 5V. In this way, the output signal of the Hall current sensor U1 can be directly read by the MCU's ADC without the need for an additional level conversion circuit.

[0023] In this circuit, the current acquisition side integrates a magnetoresistor, eliminating the need for an external sampling resistor.

[0024] The CC6902 is manufactured using advanced BiCMOS process technology and includes a high-sensitivity Hall sensor, Hall signal preamplifier, high-precision Hall temperature compensation unit, oscillator, dynamic offset cancellation circuit, and amplifier output module. In the absence of a magnetic field, the static output is 50% VCC. With a 5V supply voltage, OUT can linearly change with a magnetic field between 0.2 and 4.8V, achieving a linearity of 0.4%. The integrated dynamic offset cancellation circuitry within the CC6902 ensures that the IC's sensitivity is unaffected by external pressure and IC package stress.

[0025] The specific model of the Hall current sensor is not limited; it can be selected based on the magnitude of the floating ground current parameter of the auxiliary system.

[0026] During normal operation, the heating film and BMS share a common ground (i.e., the negative terminal B- of the battery pack and the negative terminal P- of the BMS are connected). When the energy storage system experiences faults such as overcurrent or short circuit, the protection circuit will quickly activate and disconnect the main circuit (e.g., by disconnecting the power MOSFET or contactor). At this instant, the heating film current detection module, which was originally a non-floating ground module, becomes floating ground due to the instantaneous turn-off of the discharge MOSFET, generating an extremely high common-mode voltage and back electromotive force. This voltage far exceeds the common-mode withstand voltage of conventional detection chips.

[0027] like Figure 3As shown, the floating ground current detection circuit in this embodiment is used to monitor the current of the battery cell heating film in the PACK, and the detected current is DC. The heating film is powered by DC 12V and has a rated operating current of approximately 10A. When the battery cell temperature is normal, the charging MOS (C-MOS) and discharging MOS (D-MOS) are in the open state, and P- and GND are common ground. At this time, the heating film and the BMS MCU are common ground, and the heating film does not heat. When the discharge overcurrent protection, short circuit protection, or other protection turns off the discharge MOS, the ground of the heating film and the BMS MCU are no longer common ground, but are relatively floating ground. At the moment the overcurrent protection discharge MOS is turned off, a momentary high voltage will be generated at the floating ground terminal. The nominal voltage of a single PACK product is 12.8V, which generally generates a momentary voltage spike of 60-90V. The momentary voltage spike generated by the rapid turn-off of the discharge MOS during protection is proportional to the current when the PACK triggers the discharge current protection, and is also proportional to the number of series and parallel connections of the PACK.

[0028] Hall effect current sensors can also be used for floating ground current detection in auxiliary subsystems such as air conditioning, fire protection, water immersion, and smoke detection, collecting the current on the neutral or live wire of these AC power supply devices, such as... Figures 4-6 As shown.

[0029] The BMS auxiliary subsystem described in the above embodiment introduces a Hall current sensor for floating ground current detection, which has the following advantages: Effective monitoring of floating ground current has been achieved: A systematic solution for direct and real-time monitoring of the current in key floating ground loops (such as heating, fire protection, water immersion, and smoke detection) in energy storage systems has been proposed, filling a market gap. By monitoring the current, the operating status of external modules can be accurately determined, greatly improving the visibility and safety of system operation and avoiding the risks caused by undetected system failures.

[0030] High isolation and high reliability: The use of an isolated Hall current sensor chip (isolation voltage up to 5000V) achieves complete electrical isolation between the current sensing side and the power supply and signal output sides. When some modules that were originally grounded become floating ground due to system failure, generating instantaneous high voltage at the floating ground terminal, this high isolation barrier can effectively protect the downstream MCU, ADC, and power supply from common-mode voltage surges, completely solving the problem of easy device damage in traditional current sensing chip detection solutions.

[0031] Small size, low cost, and high integration: Compared to bulky and expensive current transformer solutions, the integrated sensor chips used are small in size (such as SOIC-8 / CB-2-3 packages), low in cost, and easy to lay out on the PCB, making them very suitable for energy storage system products with strict requirements on space and cost.

[0032] AC / DC Compatible Detection: The selected isolated current sensor chip can respond to both DC and AC currents, has a wide range of applications, and eliminates the need to design different detection circuits for different types of loads, thus simplifying system design.

[0033] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims, and all such changes shall be within the scope of protection of the present invention.

Claims

1. A BMS auxiliary subsystem, characterized in that: It includes auxiliary equipment, a BMS, and a Hall current sensor; the auxiliary equipment and the BMS are not grounded; the Hall current sensor includes an isolated sampling side and a power supply output side; Its sampling side is connected in series in the main power supply circuit of the auxiliary equipment, and its power supply output side is powered by the BMS. The signal output terminal of its power supply output side is connected to the microcontroller unit of the BMS and outputs a voltage signal to characterize the current of the main power supply circuit of the auxiliary equipment.

2. The BMS auxiliary subsystem as described in claim 1, characterized in that: The Hall current sensor is a linear Hall current sensor, and its output voltage signal is linearly related to the current flowing through the sampling side.

3. The BMS auxiliary subsystem as described in claim 1, characterized in that: The Hall current sensor is integrated on the BMS printed circuit board.

4. The BMS auxiliary subsystem as described in claim 3, characterized in that: The operating voltage of the power supply output side of the Hall current sensor is compatible with the operating voltage of the microcontroller unit of the BMS.

5. The BMS auxiliary subsystem as described in claim 1, characterized in that: The auxiliary device is a cell heating film; the cell heating film is connected between the positive terminal of the battery pack and a switching path, the switching path includes a semiconductor switching device and the Hall current sensor connected in series, and is connected to the negative terminal of the BMS; the control terminal of the semiconductor switching device is electrically connected to the microcontroller unit.

6. The BMS auxiliary subsystem as described in claim 5, characterized in that: The semiconductor switching device is a MOSFET.

7. The BMS auxiliary subsystem as described in claim 1, characterized in that: The auxiliary equipment is an AC power supply device, and the Hall current sensor is connected in series in the AC power supply circuit of the AC power supply device to collect the current on its neutral or live wire.

8. The BMS auxiliary subsystem as described in claim 7, characterized in that: The AC power supply equipment is an air conditioning module, a fire protection module, or a water immersion module.

9. The BMS auxiliary subsystem as described in claim 7, characterized in that: The AC power supply equipment is connected to the BMS via RS485 communication.

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