Battery open circuit protection circuit and its failure warning protection system

Abstract

This solution provides a battery open circuit protection circuit and a failure warning protection system thereof. The battery open circuit protection circuit includes 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 operating normally, the diode is reversely cut off; when the battery is open circuited, 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 conduct through the drive unit to bridge the diode, the energy storage unit stops storing energy and the boost unit stops operating, the drive unit no longer drives the MOS tube, the current flows through the diode again and is stored in the energy storage unit, and a failure warning protection system including the battery open circuit protection circuit is designed.

Description

Technical Field

[0001] The present 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 primarily in series or in combination with series-parallel connections. Their output voltage typically ranges from 1 kV to 10 kV, with capacities exceeding 100 MWh. Their core function is to store and release grid-scale energy, and they are widely used in renewable energy consumption, grid peak regulation, and backup power. However, when a single battery cell experiences an open circuit due to a broken terminal or loose connection, the entire series battery pack is disconnected, causing system power failure. The remaining batteries are forced to withstand the full charging voltage (overvoltage exceeding 0.09%), accelerating material degradation and potentially triggering thermal runaway. Furthermore, during discharge, the load current flowing through the internal resistance of the remaining cells generates kilowatt-level power dissipation, leading to localized temperature rises exceeding 150°C and the risk of arc fires. Furthermore, the voltage surges caused by the open circuit can cause grid frequency fluctuations exceeding 0.1 Hz, threatening regional grid stability.

[0003] Battery jumper modules (also known as battery bypass modules) are a key technical solution for single-cell open circuits in high-voltage energy storage systems. Their core principle is to bypass faulty batteries through the unidirectional conductivity of diodes: when the battery is operating normally, the diode is reverse-biased, blocking the battery. However, when the battery is open-circuited, the voltage across the battery suddenly rises, causing the diode to conduct forward, bypassing the current to other cells and maintaining system operation. However, this diode-based jumper approach suffers from high power consumption and high temperature rise. The resulting lifespan degradation, safety risks, and efficiency losses directly limit the reliability and cost-effectiveness of the entire battery jumper system.

[0004] Therefore, there is an urgent need to develop open-circuit protection technology with low 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 designs 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:

[0007] The freewheeling unit, overcurrent unit and energy storage unit are connected in parallel at both ends of a single battery, wherein the energy storage unit acts on the overcurrent unit through the boost unit and the drive unit, the freewheeling unit is a diode, and the overcurrent unit is a MOS tube;

[0008] When the battery is working normally, the diode is reverse cutoff;

[0009] 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 the set threshold, the boost unit drives the MOS tube to turn on through the drive unit to jumper 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.

[0010] This solution provides a battery failure early warning protection system, which is applied to series-connected battery packs and includes:

[0011] An open circuit protection unit, wherein the open circuit protection unit includes at least one open circuit protection circuit connected in parallel to each battery,

[0012] A battery monitoring unit, wherein the battery monitoring unit includes a current monitoring sensor connected to each battery for collecting battery parameters;

[0013] A battery detection aggregation terminal that communicates with the battery monitoring unit and is used to aggregate battery parameters of multiple batteries;

[0014] The capacity verification host communicates with the battery detection aggregation terminal and is used to verify or predict the battery capacity based on the collected battery parameters.

[0015] Compared with the existing technology, this technical solution has the following characteristics and beneficial effects:

[0016] 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. It can greatly reduce the power consumption of the battery open circuit protection circuit while reducing the temperature rise of the entire circuit. 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.

[0017] The failure warning protection system designed in this solution is combined with a battery protection circuit. It can detect and warn low-capacity batteries in advance. At the same time, it can actively respond and provide open-circuit protection when a battery failure occurs, ensuring that the battery pack can stably supply power to the DC load when the DC power supply fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a module diagram of the battery open circuit protection circuit.

[0019] Figure 2 This is the circuit diagram of the battery open circuit protection circuit.

[0020] Figure 3 It is the open circuit protection logic diagram of the battery open circuit protection circuit.

[0021] Figure 4 This is a usage scenario diagram of the battery open circuit protection circuit.

[0022] Figure 5 It is a framework diagram of a battery failure early warning protection system combined with a battery open circuit protection circuit.

[0023] 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

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0025] It should be understood by those skilled in the art that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "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 accompanying 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.

[0026] Example 1

[0027] like Figure 1 As shown, this solution provides a battery open circuit protection circuit for open circuit protection of a single battery in a series-connected battery pack, including:

[0028] The freewheeling unit, overcurrent unit and energy storage unit are connected in parallel at both ends of a single battery, wherein the energy storage unit acts on the overcurrent unit through the boost unit and the drive unit, the freewheeling unit is a diode, and the overcurrent unit is a MOS tube;

[0029] When the battery is working normally, the diode is reverse cutoff;

[0030] 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 the set threshold, the boost unit drives the MOS tube to turn on through the drive unit to jumper 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.

[0031] 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%.

[0032] The freewheeling unit of this 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 at 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 this solution does not need to obtain electrical energy from the battery, will not cause a load on the battery, and there will be no problem of high battery self-discharge rate.

[0033] In addition, when the battery is open-circuited, since the internal resistance of the freewheeling unit's diode is smaller than the internal resistance of the faulty battery, the current will flow through the freewheeling unit's diode on its own, thereby triggering a subsequent cross-circuit protection cycle. Therefore, the battery open-circuit protection circuit does not need to additionally change the battery to open or non-open circuit, which greatly reduces the number of electronic components, resulting in a small temperature rise in the overall battery open-circuit protection circuit.

[0034] 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 electrical energy flowing through the diode of the freewheeling unit.

[0035] 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 that is conductive with the transistor Q3, and a buck-boost circuit that is conductive with the transistor Q4 and the front-stage boost circuit. When the voltage of the energy storage unit is within a first threshold range, the transistor Q3 is cut off and the transistor Q4 is turned on, and the voltage is input to the buck-boost circuit through the transistor Q4 for boosting. When the voltage of the energy storage unit is within a second threshold range, the transistor Q3 is turned on and the transistor Q4 is cut off, and the voltage is input to the front-stage boost circuit through the transistor Q3 for boosting and then input to the buck-boost circuit for boosting, wherein the minimum value of the first threshold range is equal to the maximum value of the second threshold range.

[0036] In some embodiments, when the boost unit boosts the voltage to 12V, the boost unit drives the MOS tube to be turned on via the driving unit to bridge the diode.

[0037] In some embodiments, the boost unit sets the voltage threshold to 5V through the adjustable resistor RP1, transistor Q1 and transistor Q4. The corresponding first threshold range is 5~35V, and the second threshold range is 0.45~5V. The operating voltage range of the battery open circuit protection circuit of this solution can be within a wide range of 0.48-35V.

[0038] Specifically, the emitters of transistors Q3 and Q4 are both 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 pre-stage boost circuit, and the output end of the pre-stage boost circuit is connected to the buck-boost circuit.

[0039] About the pre-stage boost circuit of this solution:

[0040] The front-stage boost circuit includes a DC boost voltage regulator chip. The first input terminal of the DC boost voltage regulator chip is connected to the collector of the transistor Q3 through a resistor R5, the second input terminal is connected to the collector of the transistor Q3 through an inductor L2, the third input terminal is connected to the positive terminal of the battery through a resistor R1, the 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 the two ends of the resistor R3 are connected in parallel with a capacitor C5. 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.

[0041] In some embodiments, the DC boost voltage regulator chip is GS1662.

[0042] About the buck-boost circuit of this solution:

[0043] The buck-boost circuit includes a step-down voltage regulator chip. The output circuit of pin 1 of the step-down voltage regulator chip is connected to the positive terminal of the battery through capacitor C3. The output circuit of pin 2 is connected to the output circuit of pin 4 through inductor L1, and the output circuit of pin 4 is connected to the positive terminal of the battery through 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 diode D2 is connected to the positive terminal of the battery, and the other end is connected to the output circuit of pin 1 and the drive unit respectively. Transistor Q4 and the pre-stage boost circuit are connected to the output circuit of pin 1.

[0044] In some embodiments, the buck regulator chip is an LM2596 chip.

[0045] The drive 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.

[0046] It should be noted that when the voltage output by the boost unit reaches a set threshold, the transistor Q1 in the drive 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, it can bridge the diode of the freewheeling unit.

[0047] 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.

[0048] In some embodiments, the battery open circuit protection circuit is suitable for application scenarios of battery packs that use photovoltaic cells, lead-acid batteries, and lithium batteries in series, and has the performance of unidirectional conduction and low-loss conduction.

[0049] The working logic diagram of the battery open circuit protection circuit is as follows Figure 3As 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 faulty battery, the current flows through the MOS tube instead of the diode of the freewheeling unit. The corresponding energy storage unit no longer stores energy, the boost unit stops working, and the drive unit no longer triggers 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.

[0050] like Figure 4 As shown, the series-connected battery pack 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 pack directly supplies power to the DC load. At this time, when the batteries in the series-connected battery pack are open-circuited or have insufficient capacity, the battery open-circuit protection circuit of this solution will bypass the faulty battery to ensure that the battery pack can continue to supply power to the DC load; and when the DC power supply is restored, the battery pack can be charged. Since the diode of the freewheeling unit is reversely connected at both ends of the battery, current cannot flow through the battery open-circuit protection circuit, thereby preventing the battery from being charged short-circuited.

[0051] Example 2

[0052] 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-connected battery pack to achieve failure warning protection, including:

[0053] an open circuit protection unit, wherein the open circuit protection unit comprises at least one open circuit protection circuit connected in parallel to each battery;

[0054] A battery monitoring unit, wherein the battery monitoring unit includes a current monitoring sensor connected to each battery for collecting battery parameters;

[0055] A battery detection aggregation terminal that communicates with the battery monitoring unit and is used to aggregate battery parameters of multiple batteries;

[0056] The capacity verification host communicates with the battery detection aggregation terminal and is used to verify or predict the battery capacity based on the collected battery parameters.

[0057] The introduction of the open circuit protection circuit in the open circuit protection unit is shown in the first embodiment.

[0058] In some embodiments, 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.

[0059] In some embodiments, the battery is any one of a photovoltaic cell, a lead-acid battery, and a lithium battery.

[0060] 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.

[0061] In some embodiments, the current monitoring sensors of different batteries communicate with each other, and ultimately one current monitoring sensor sends the 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.

[0062] In some embodiments, the capacity checking host performs battery capacity checking based on the collected battery parameters.

[0063] In addition, in some embodiments, the core capacity host is equipped with a built-in 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.

[0064] The battery parameter set collected during training and testing of the battery capacity prediction model includes battery voltage, internal resistance, temperature, and battery complex impedance at nine frequencies, as well as discharge rate and depth. The nine frequencies include 1495 Hz, 484 Hz, 158 Hz, 51 Hz, 17 Hz, 5 Hz, 1.9 Hz, 0.48 Hz, and 0.06 Hz. These complex impedances at different frequencies enable the model to better adapt to different operating conditions and battery states. The impact of impedance at different frequencies on battery capacity may change with battery use and aging. The model can learn more complex relationships from impedance data at multiple frequencies, thereby improving prediction accuracy and generalization.

[0065] The specific method for training the battery capacity prediction model is as follows: a neural network model is trained using the collected battery parameter set and the corresponding battery capacity, and the weights and biases of the neural network model are optimized using a backpropagation algorithm to obtain a battery capacity prediction model that can predict battery capacity based on the battery parameter set. In some embodiments, the collected battery parameter set is cleaned and sorted to remove outliers and missing values and normalized to make the data in the collected battery parameter set more evenly distributed, facilitating subsequent neural network model learning.

[0066] It should be noted that in some embodiments, when the core capacity host detects or predicts that a battery in the battery pack has insufficient capacity, it issues a warning signal to remind staff to promptly replace the current battery, thereby providing an early warning of failure. Furthermore, if the core capacity host fails to issue a warning signal but a battery in the battery pack has an open circuit or insufficient capacity, an open circuit protection unit is implemented to ensure that the battery pack can still provide normal power.

[0067] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. In order 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.

[0068] The above embodiments merely illustrate several embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A battery open circuit protection circuit, characterized in that: include: A freewheeling unit, an overcurrent unit, and an energy storage unit are connected in parallel at both ends of a single battery. 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 transistor. The internal resistance of the diode is smaller than the internal resistance of the open-circuit battery, and the internal resistance of the MOS transistor is smaller than the internal resistance of the diode. When the battery is working normally, the diode is reverse cutoff; When the battery is open-circuited, the internal resistance of the diode of the freewheeling unit is less than the internal resistance of the faulty battery, and the current will flow through the diode of the freewheeling unit by itself. After the current flows through the diode, the energy storage unit stores the electric energy, and at the same time drives 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, and the energy storage unit stops storing electric 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. 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, and a collector of the transistor Q4. A transistor Q3 is connected in series, a front-stage boost circuit is turned on with the transistor Q3, and a buck-boost circuit is turned on with the transistor Q4 and the front-stage boost circuit. When the voltage of the energy storage unit is within a first threshold range, 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 for boosting. When the voltage of the energy storage unit is within a second threshold range, 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 for boosting and then input to the buck-boost circuit for boosting, wherein the minimum value of the first threshold range is equal to the maximum value of the second threshold range.

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 drive 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.

4. 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.

5. A battery failure 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 4 connected in parallel to each battery, A battery monitoring unit, wherein the battery monitoring unit includes a current monitoring sensor connected to each battery for collecting battery parameters; A battery detection aggregation terminal that communicates with the battery monitoring unit and is used to aggregate battery parameters of multiple batteries; The capacity verification host communicates with the battery detection aggregation terminal and is used to verify or predict the battery capacity based on the collected battery parameters.

6. The battery failure warning protection system according to claim 5, 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.

7. The battery failure warning protection system according to claim 6, 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. 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 9 frequencies, wherein the battery complex impedance at 9 frequencies includes battery complex impedance at 1495HZ, 484HZ, 158HZ, 51HZ, 17HZ, 5HZ, 1.9HZ, 0.48HZ and 0.06HZ.

8. The battery failure warning protection system according to claim 6, 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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