Storage battery open circuit protection circuit and failure early warning protection system thereof

Abstract

The invention provides a storage battery open circuit protection circuit and a failure early warning protection system thereof, the storage battery open circuit protection circuit comprises a follow current unit, an over-current unit and an energy storage unit which are connected in parallel at two ends of a single storage battery, the energy storage unit acts on the over-current unit through a boost unit and a driving unit, the follow current unit is a diode, and the over-current unit is a diode. The over-current unit is an MOS (Metal Oxide Semiconductor) tube; when the storage battery works normally, the diode is reversely cut off; when the storage battery works in an open circuit mode, electric energy is stored by the energy storage unit after current flows through the diode, the boosting unit is driven to boost at the same time, when the boosting unit boosts to a set threshold value, the boosting unit drives the MOS tube to be conducted through the driving unit so as to bridge the diode, the energy storage unit stops storing the electric energy, the boosting unit stops working at the same time, and the driving unit does not drive the MOS tube any more. After the current flows through the diode again, the electric energy is stored by the energy storage unit, and a failure early warning protection system comprising a storage battery open circuit protection circuit is designed.

Description

Technical Field

[0001] The invention relates to the field of battery protection, and in particular to a battery open circuit protection circuit and a failure warning protection system thereof. Background Art

[0002] High-voltage energy storage systems are large-capacity energy storage devices composed of hundreds to thousands of batteries connected in series or in series-parallel. The output voltage is usually 1 kV to 10 kV, and the capacity can reach more than 100 MWh. Its core function is to achieve grid-level energy storage and release, and it is widely used in the fields of new energy consumption, grid peak regulation, and backup power supply. When a single battery is open-circuited due to pole breakage, loose connection, etc., the circuit of the entire series-connected battery group will be interrupted, causing the system power supply to fail; the remaining batteries are forced to withstand the full charging voltage (overvoltage of more than 0.09%), thereby accelerating material aging and possibly triggering thermal runaway; at the same time, when discharging, the load current flows through the internal resistance of the remaining batteries to generate kilowatt-level power consumption, resulting in a local temperature rise of more than 150°C, and there is a risk of arc fire. In addition, the voltage mutation caused by the open circuit may cause the grid frequency to fluctuate by more than 0.1Hz, threatening the stability of the regional power grid.

[0003] The battery jumper module (also known as the battery bypass module) is an important technical means to deal with single-cell open circuit in high-voltage energy storage systems. Its core principle is to bypass the faulty battery through the unidirectional conductivity of the diode: when the battery is working normally, the diode is reversely cut off, and when the battery is open circuit, the voltage at both ends of the battery rises suddenly, and the diode is forward-conducted, bypassing the current to other batteries to maintain system operation. However, this method of using diodes to achieve jumper connection has the problems of large power consumption and high temperature rise, and the resulting life attenuation, safety risks and efficiency losses directly restrict the reliability and economy of the entire battery jumper system.

[0004] Therefore, there is an urgent need to develop open-circuit protection technology with small temperature rise to ensure the safe operation of high-voltage energy storage systems and reduce operation and maintenance costs. Summary of the invention

[0005] The purpose of the present invention is to provide a battery open circuit protection circuit and a failure warning protection system thereof, and to design a battery open circuit protection circuit with small temperature rise and a failure warning protection system using the battery open circuit protection circuit.

[0006] To achieve the above objectives, the present technical solution provides a battery open circuit protection circuit, comprising: A freewheeling unit, an overcurrent unit and an energy storage unit connected in parallel at both ends of a single battery, wherein the energy storage unit acts on the overcurrent unit through a boost unit and a drive unit, the freewheeling unit is a diode, and the overcurrent unit is a MOS tube; When the battery is working normally, the diode is reverse cutoff; When the battery is working in an open circuit, the current flows through the diode and is stored in the energy storage unit, while driving the boost unit to boost the voltage. When the boost unit boosts the voltage to a set threshold, the boost unit drives the MOS tube to turn on through the drive unit to bridge the diode. The energy storage unit stops storing energy and the boost unit stops working. The drive unit no longer drives the MOS tube, and the current flows through the diode again and is stored in the energy storage unit.

[0007] This solution provides a battery failure early warning protection system, which is applied to a series of battery packs and includes: An open circuit protection unit, wherein the open circuit protection unit includes at least one open circuit protection circuit connected in parallel to each storage battery, A battery monitoring unit, wherein the battery monitoring unit includes a current monitoring sensor connected to each battery for collecting battery parameters of the battery; A battery detection collection terminal communicating with a battery monitoring unit, used to collect battery parameters of multiple batteries; The capacity verification host that communicates with the battery detection collection terminal is used to verify or predict the battery capacity based on the collected battery parameters.

[0008] Compared with the prior art, this technical solution has the following characteristics and beneficial effects: The energy storage unit of the battery open circuit protection circuit designed in this scheme does not need to draw power from the battery for energy storage, and does not require additional software programs to judge and compare whether the battery is open or not, which can greatly reduce the power consumption of the battery open circuit protection circuit while reducing the temperature rise of the entire circuit; and the operating voltage range of the battery open circuit protection circuit is wide, and the operating current of a single module is as high as 50A and can support multiple parallel connections. In addition, the battery open circuit protection circuit adopts pure hardware circuit control, and there is no risk of software miscontrol.

[0009] The failure warning protection system designed in this scheme is combined with a battery protection circuit, which can detect and warn low-capacity batteries in advance. At the same time, it can also actively respond to open-circuit protection when a battery fails, to ensure that the battery pack can stably supply power to the DC load when the DC power supply fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a module schematic diagram of the battery open circuit protection circuit.

[0011] Figure 2 It is the circuit diagram of the battery open circuit protection circuit.

[0012] Figure 3 It is the open circuit protection logic diagram of the battery open circuit protection circuit.

[0013] Figure 4 This is a usage scenario diagram of the battery open circuit protection circuit.

[0014] Figure 5 It is a framework diagram of a battery failure early warning protection system combined with a battery open circuit protection circuit.

[0015] In the figure: ①-battery open circuit protection circuit; ②-positive terminal; ③-negative terminal; ④-energy storage unit; ⑤-boost unit; ⑥-drive unit; ⑦-overcurrent unit; ⑧-freewheeling unit. DETAILED DESCRIPTION

[0016] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0017] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0018] Embodiment 1 like Figure 1 As shown, the present solution provides a battery open circuit protection circuit for performing open circuit protection on a single battery in a series-connected battery pack, comprising: A freewheeling unit, an overcurrent unit and an energy storage unit connected in parallel at both ends of a single battery, wherein the energy storage unit acts on the overcurrent unit through a boost unit and a drive unit, the freewheeling unit is a diode, and the overcurrent unit is a MOS tube; When the battery is working normally, the diode is reverse cutoff; When the battery is working in an open circuit, the current flows through the diode and is stored in the energy storage unit, while driving the boost unit to boost the voltage. When the boost unit boosts the voltage to a set threshold, the boost unit drives the MOS tube to turn on through the drive unit to bridge the diode. The energy storage unit stops storing energy and the boost unit stops working. The drive unit no longer drives the MOS tube, and the current flows through the diode again and is stored in the energy storage unit.

[0019] It should be noted that when the battery is open-circuited, the battery open-circuit protection circuit enters a cyclic cross-circuit protection period. In each cross-circuit protection period, when current flows through the diode of the freewheeling unit, it is defined as the freewheeling unit working, and when current flows through the MOS tube of the overcurrent unit, it is defined as the overcurrent unit working. In each cross-circuit protection period, the freewheeling unit working accounts for 10% and the overcurrent unit working accounts for 90%.

[0020] The freewheeling unit of the present solution is connected to both ends of the positive terminal and the negative terminal of the battery, and the energy storage unit is connected in parallel to both ends of the battery to store electrical energy when current flows through the diode. The advantage of this is that the energy storage unit of the present solution does not need to obtain electrical energy from the battery, will not cause a load on the battery, and there is no problem of high self-discharge rate of the battery.

[0021] In addition, when the battery is working in an open circuit, since the internal resistance of the diode of the freewheeling unit is smaller than the internal resistance of the faulty battery, the current will flow through the diode of the freewheeling unit by itself, thereby triggering a subsequent cross-circuit protection cycle. Therefore, the battery open circuit protection circuit does not need to additionally change the battery to an open circuit or a non-open circuit, which greatly reduces the number of electronic components and results in a small temperature rise of the overall battery open circuit protection circuit.

[0022] Furthermore, the specific circuit diagram of the battery open circuit protection circuit is as follows: Figure 2 As shown, the energy storage unit is an electrolytic capacitor and the positive electrode of the electrolytic capacitor is connected to the negative terminal of the battery, which is used to store the electric energy flowing through the diode of the freewheeling unit.

[0023] The boost unit includes an adjustable resistor RP1 connected in parallel with the energy storage unit, a transistor Q4 whose base is connected in series with the adjustable circuit RP1, a transistor Q3 whose base is connected in series with the collector of the transistor Q4, a front-stage boost circuit turned on with the transistor Q3, and a buck-boost circuit turned on with the transistor Q4 and the front-stage boost circuit. When the voltage of the energy storage unit is in the first threshold interval, the transistor Q3 is turned off and the transistor Q4 is turned on, and the voltage is input to the buck-boost circuit through the transistor Q4 to be boosted; when the voltage of the energy storage unit is in the second threshold interval, the transistor Q3 is turned on and the transistor Q4 is turned off, and the voltage is input to the front-stage boost circuit through the transistor Q3, then boosted, and then input to the buck-boost circuit to be boosted, wherein the minimum value of the first threshold interval is equal to the maximum value of the second threshold interval.

[0024] In some embodiments, when the boost unit boosts the voltage to 12V, the boost unit drives the MOS tube to be turned on through the driving unit to bridge the diode.

[0025] In some embodiments, the boost unit sets the voltage threshold to 5V through the adjustable resistor RP1, the transistor Q1 and the transistor Q4, the corresponding first threshold interval is 5~35V, and the second threshold interval is 0.45~5V. The operating voltage range of the battery open circuit protection circuit of this scheme can be within a wide range of 0.48-35V.

[0026] Specifically, the emitters of transistors Q3 and Q4 are connected to the negative terminal of the battery through resistor R7, the collector of transistor Q4 is connected to the buck-boost circuit, the collector of transistor Q3 is connected to the previous stage boost circuit, and the output end of the previous stage boost circuit is connected to the buck-boost circuit.

[0027] About the pre-stage boost circuit of this solution: The front-stage boost circuit includes a DC boost voltage regulator chip, a first input terminal of the DC boost voltage regulator chip is connected to the collector of the transistor Q3 through a resistor R5, a second input terminal is connected to the collector of the transistor Q3 through an inductor L2, a third input terminal is connected to the positive terminal of the battery through a resistor R1, a fourth input terminal is directly connected to the positive terminal of the battery, and the resistor R5 is connected to the positive terminal of the battery through a parallel diode D3 and a capacitor C2, the output terminal of the DC boost voltage regulator chip is connected to the buck-boost circuit through a resistor R3 and a diode D4, and capacitor C5 is connected in parallel at both ends of the resistor R3, and the output terminal of the DC boost voltage regulator chip is further connected to the second input terminal of the DC boost voltage regulator chip through a resistor R6 and a diode D7.

[0028] In some embodiments, the DC boost voltage regulator chip is GS1662.

[0029] About the buck-boost circuit of this solution: The buck-boost circuit includes a step-down voltage regulator chip, wherein the output circuit of pin 1 of the step-down voltage regulator chip is connected to the positive terminal of the battery through a capacitor C3, the output circuit of pin 2 is connected to the output circuit of pin 4 through an inductor L1, and the output circuit of pin 4 is connected to the positive terminal of the battery through a capacitor C1, the output circuit of pin 5 is connected to the output circuit of pin 3 and to the positive terminal of the battery, one end of a diode D2 is connected to the positive terminal of the battery, and the other end is respectively connected to the output circuit of pin 1 and a driving unit, and a transistor Q4 and a pre-stage boost circuit are connected to the output circuit of pin 1.

[0030] In some embodiments, the buck regulator chip is a LM2596 chip.

[0031] The driving unit includes a transistor Q1, a resistor R2 and a diode D6 forming a loop, wherein the collector of the transistor Q1 is connected to the positive terminal of the battery, the emitter of the transistor Q1 is connected to the resistor R2, the cathode of the diode D6 is connected to the resistor R2 and the anode is connected to the base of the transistor Q1, the connection circuit of the circuit R2 and the diode D6 is connected to the overcurrent unit, and the connection circuit of the transistor Q1 and the diode D6 is connected to the boost unit through the resistor R4.

[0032] It should be noted that when the voltage output by the boost unit reaches a set threshold, the transistor Q1 in the driving unit is triggered to drive the MOS tube of the overcurrent unit to turn on. When the MOS tube of the overcurrent unit is turned on, the diode of the freewheeling unit can be connected across it.

[0033] In addition, the battery open circuit protection circuit provided by this solution is driven by the hardware structure, the operating current of a single battery open circuit protection circuit is 50A and one or more battery open circuit protection circuits can be connected in parallel to the same battery.

[0034] In some embodiments, the battery open circuit protection circuit is suitable for application scenarios of battery packs that are used in series with photovoltaic cells, lead-acid batteries, and lithium batteries, and has the performance of unidirectional conduction and low-loss conduction.

[0035] The working logic diagram of the battery open circuit protection circuit is as follows Figure 3 As shown, when the battery is working normally, the battery open circuit protection circuit does not work; when the battery is open-circuited, since the internal resistance of the diode of the freewheeling unit is smaller than the internal resistance of the open-circuited battery, the current flows through the diode of the freewheeling unit and the electric energy is stored in the energy storage unit. At the same time, when the boost unit continuously boosts the voltage to the set threshold, the drive unit is triggered to drive the MOS tube of the overcurrent unit to turn on. At this time, since the internal resistance of the MOS tube is much smaller than the diode of the freewheeling unit and the internal resistance of the failed battery, the current flows through the MOS tube instead of the diode of the freewheeling unit, and the corresponding energy storage unit no longer stores energy. The boost unit stops working, which causes the drive unit to no longer trigger the MOS tube of the overcurrent unit to turn on. After the MOS tube is cut off, the current continues to flow through the diode.

[0036] like Figure 4As shown, the series-connected battery group protected by the battery open-circuit protection circuit is connected in parallel to the DC power supply and the DC load. When the AC voltage is lost or the DC power supply fails, the series-connected battery group directly supplies power to the DC load. At this time, when the batteries of the series-connected battery group are open-circuited or have insufficient capacity, the battery open-circuit protection circuit of this scheme will bypass the failed battery to ensure that the battery group can continue to supply power to the DC load; and when the DC power supply is restored, the battery group can be charged. Since the diode of the freewheeling unit is reversely connected at both ends of the battery, the current cannot flow through the battery open-circuit protection circuit, and thus will not cause a charging short circuit of the battery.

[0037] Embodiment 2 like Figure 5 As shown, this solution provides a battery failure warning protection system combined with a battery open circuit protection circuit, which is applied to a series of battery packs to achieve failure warning protection, including: An open circuit protection unit, wherein the open circuit protection unit includes at least one open circuit protection circuit connected in parallel to each storage battery; A battery monitoring unit, wherein the battery monitoring unit includes a current monitoring sensor connected to each battery for collecting battery parameters of the battery; A battery detection collection terminal communicating with a battery monitoring unit, used to collect battery parameters of multiple batteries; The capacity verification host that communicates with the battery detection collection terminal is used to verify or predict the battery capacity based on the collected battery parameters.

[0038] The introduction of the open circuit protection circuit in the open circuit protection unit is shown in the first embodiment.

[0039] In some embodiments, the battery pack is connected in parallel to the DC power source and the DC load. When the DC power source fails, the battery pack supplies power to the DC load.

[0040] In some embodiments, the storage battery is any one of a photovoltaic cell, a lead-acid battery, and a lithium battery.

[0041] In some embodiments, the current monitoring sensor is used to collect battery parameters including the battery's internal resistance, voltage, temperature, and battery complex impedance at a specified frequency. It should be noted that the battery's voltage and temperature are collected in real time, while other battery parameters are collected periodically and after remote control testing.

[0042] In some embodiments, current monitoring sensors of different batteries communicate with each other, and eventually one current monitoring sensor sends battery parameters of all batteries to the battery detection aggregation terminal; alternatively, each current monitoring sensor sends the battery parameters of its own battery to the battery detection aggregation terminal.

[0043] In some embodiments, the capacity checking host performs battery capacity checking based on the collected battery parameters.

[0044] In addition, in some embodiments, the core capacity host is loaded with a battery capacity prediction model, wherein the capacitance prediction model is obtained by training a neural network model with a battery parameter group and a corresponding battery capacity, such as inputting the collected battery parameter group into the battery capacity prediction model to obtain the predicted battery capacity of the battery.

[0045] The battery parameter groups collected during the training and testing of the battery capacity prediction model include battery voltage, internal resistance, temperature, battery complex impedance at 10 frequencies, discharge rate and depth. The battery complex impedance at 10 frequencies includes battery complex impedance at 1495HZ, 484HZ, 158HZ, 51HZ, 17HZ, 5HZ, 1.9HZ, 0.48HZ, and 0.06HZ. The battery complex impedance at these different frequencies can make the model better adapt to different working conditions and battery states. The degree of influence of impedance at different frequencies on battery capacity may change with the use and aging of the battery. The model can learn more complex relationships from impedance data at multiple frequencies, thereby improving the accuracy and generalization of predictions.

[0046] Regarding the training of the battery capacity prediction model, the specific method is: using the collected battery parameter group and the corresponding battery capacity to train the neural network model, and optimizing the weight and bias of the neural network model through the back propagation algorithm to obtain a battery capacity prediction model that can predict the battery capacity based on the battery parameter group. In some embodiments, the collected battery parameter group is cleaned and sorted to remove abnormal values ​​and missing values ​​and normalized to make the data in the collected battery parameter group more evenly distributed, so as to facilitate the subsequent neural network model learning.

[0047] It should be noted that in some embodiments, when the core capacity host detects that the battery capacity of a battery in the battery pack is insufficient or predicts that the battery capacity of a battery is insufficient, a reminder signal is issued to remind the staff to replace the current battery in time, which can serve as an early warning of failure. Furthermore, when the core capacity host fails to issue a reminder signal but the battery in the battery pack is open-circuited or the battery capacity is insufficient, an open-circuit protection unit is used to ensure that the battery pack can still supply power normally.

[0048] Those skilled in the art should understand that the technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A battery open circuit protection circuit, characterized in that: include: A freewheeling unit, an overcurrent unit and an energy storage unit connected in parallel at both ends of a single battery, wherein the energy storage unit acts on the overcurrent unit through a boost unit and a drive unit, the freewheeling unit is a diode, and the overcurrent unit is a MOS tube; When the battery is working normally, the diode is reverse cutoff; When the battery is working in an open circuit, the current flows through the diode and is stored in the energy storage unit, while driving the boost unit to boost the voltage. When the boost unit boosts the voltage to a set threshold, the boost unit drives the MOS tube to turn on through the drive unit to bridge the diode. The energy storage unit stops storing energy and the boost unit stops working. The drive unit no longer drives the MOS tube, and the current flows through the diode again and is stored in the energy storage unit.

2. The battery open circuit protection circuit according to claim 1, characterized in that: The energy storage unit is an electrolytic capacitor and the positive electrode of the electrolytic capacitor is connected to the negative terminal of the battery.

3. The battery open circuit protection circuit according to claim 1, characterized in that: The boost unit includes an adjustable resistor RP1 connected in parallel with the energy storage unit, a transistor Q4 whose base is connected in series with the adjustable circuit RP1, a transistor Q3 whose base is connected in series with the collector of the transistor Q4, a front-stage boost circuit turned on with the transistor Q3, and a buck-boost circuit turned on with the transistor Q4 and the front-stage boost circuit. When the voltage of the energy storage unit is in the first threshold interval, the transistor Q3 is turned off and the transistor Q4 is turned on, and the voltage is input to the buck-boost circuit through the transistor Q4 to be boosted; when the voltage of the energy storage unit is in the second threshold interval, the transistor Q3 is turned on and the transistor Q4 is turned off, and the voltage is input to the front-stage boost circuit through the transistor Q3, then boosted, and then input to the buck-boost circuit to be boosted, wherein the minimum value of the first threshold interval is equal to the maximum value of the second threshold interval.

4. The battery open circuit protection circuit according to claim 1, characterized in that: The driving unit includes a transistor Q1, a resistor R2 and a diode D6 forming a loop, wherein the collector of the transistor Q1 is connected to the positive terminal of the battery, the emitter of the transistor Q1 is connected to the resistor R2, the cathode of the diode D6 is connected to the resistor R2 and the anode is connected to the base of the transistor Q1, the connection circuit of the circuit R2 and the diode D6 is connected to the overcurrent unit, and the connection circuit of the transistor Q1 and the diode D6 is connected to the boost unit through the resistor R4.

5. The battery open circuit protection circuit according to claim 1, characterized in that: One or more battery open circuit protection circuits are connected in parallel to the same battery.

6. The battery open circuit protection circuit according to claim 1, characterized in that: The internal resistance of a diode is smaller than the internal resistance of an open-circuit battery, and the internal resistance of a MOS tube is smaller than the internal resistance of a diode.

7. A battery failure early warning protection system, applied to a battery pack connected in series, characterized in that: include: An open circuit protection unit, wherein the open circuit protection unit comprises at least one open circuit protection circuit according to any one of claims 1 to 6 connected in parallel to each storage battery, A battery monitoring unit, wherein the battery monitoring unit includes a current monitoring sensor connected to each battery for collecting battery parameters of the battery; A battery detection collection terminal communicating with a battery monitoring unit, used to collect battery parameters of multiple batteries; The capacity verification host that communicates with the battery detection collection terminal is used to verify or predict the battery capacity based on the collected battery parameters.

8. The battery failure early warning protection system according to claim 7, characterized in that: The battery pack is connected in parallel to the DC power supply and the DC load. When the DC power supply fails, the battery pack supplies power to the DC load.

9. The battery failure early warning protection system according to claim 7, characterized in that: The core capacity host is equipped with a battery capacity prediction model, wherein the capacitance prediction model is obtained by training a neural network model through a battery parameter group and a corresponding battery capacity, and the collected battery parameter group is input into the battery capacity prediction model to obtain the predicted battery capacity of the battery, wherein the battery parameter group includes battery voltage, internal resistance, temperature, and battery complex impedance, discharge rate and depth at 10 frequencies, wherein the battery complex impedance at 10 frequencies includes battery complex impedance at 1495HZ, 484HZ, 158HZ, 51HZ, 17HZ, 5HZ, 1.9HZ, 0.48HZ, and 0.06HZ.

10. The battery failure early warning protection system according to claim 7, characterized in that: When the capacity checking host detects that the battery capacity of a battery in the battery pack is insufficient or predicts that the battery capacity of a battery is insufficient, a reminder signal is sent to remind the staff to replace the current battery in time.

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