CN116231806A

CN116231806A - Short-circuit protection device and short-circuit protection method of battery management system

Info

Publication number: CN116231806A
Application number: CN202310242959.5A
Authority: CN
Inventors: 李明星; 杨冬强; 卢校山; 王文义
Original assignee: Hangzhou Huasu Technology Co ltd
Current assignee: Hangzhou Huasu Technology Co ltd
Priority date: 2023-03-14
Filing date: 2023-03-14
Publication date: 2023-06-06

Abstract

The invention relates to a short-circuit protection device and a short-circuit protection method of a battery management system, wherein the device comprises: the energy storage module, the discharging MOS and the charging MOS are sequentially connected in series; a voltage detection circuit electrically connected to both ends of the load, the voltage detection circuit being configured to detect a voltage of the load; the control module is used for controlling the discharge MOS to be disconnected when the current detection circuit detects that the power supply current is larger than a preset current value under the condition of triggering the discharge MOS to be started, and judging whether the load is short-circuited or not according to the currently detected voltage of the load and the voltage of the load before the discharge MOS is triggered to be started so as to prevent false short-circuit protection. The voltage acquisition operation is carried out on the load twice by controlling the conduction state of the discharge MOS and the voltage detection circuit, so that the accurate short-circuit protection is effectively realized.

Description

Short-circuit protection device and short-circuit protection method of battery management system

Technical Field

The present invention relates to the field of battery management technologies, and in particular, to a short-circuit protection device and a short-circuit protection method for a battery management system.

Background

As the usage amount of lithium batteries in the fields of communication base stations, home energy storage, data centers and the like is increasing, the safety requirement on a Battery Management System (BMS) is also increasing, and the short-circuit protection plays a very important role in the reliability and stability of the whole system in the lithium battery management system, so that it is necessary to provide a short-circuit protection method to ensure the discharge safety of the lithium batteries.

The current short-circuit protection mostly adopts a delay judging method, namely, after an external short-circuit is identified by adopting an MCU or an AFE (Analog front end), judging whether the short-circuit is in a short-circuit state again after a certain time delay, and if so, judging the short-circuit. The method is a test for the MOS tube, because when a real short circuit occurs, the current can be increased sharply in the time of delay, the MOS tube can be excessively lost or directly burst, and meanwhile, under the condition of combining actual use, the high current can last for millisecond level, so that equipment damage and accidents are likely to be caused.

Therefore, it is necessary to provide a short-circuit protection device which accurately determines whether a load end is short-circuited, can timely and effectively realize short-circuit protection and MOS transistor functional safety protection, and is suitable for different load types to solve the above-mentioned technical problems.

Disclosure of Invention

In order to solve the technical problems, the invention provides a short-circuit protection device of a battery management system. The method solves the technical problems that the delay judging short circuit is adopted in the prior art, so that the MOS tube is possibly damaged due to excessive loss effect.

The technical effects of the invention are realized by the following steps:

a short circuit protection device of a battery management system, comprising:

the device comprises an energy storage module, a discharging MOS and a charging MOS, wherein the positive end of the energy storage module is used for being electrically connected with one end of a load, and the negative end of the energy storage module is electrically connected with the other end of the load after being sequentially connected with the discharging MOS and the charging MOS in series;

a voltage detection circuit electrically connected to both ends of the load, the voltage detection circuit being configured to detect a voltage of the load;

the current detection circuit is used for monitoring the power supply current of the energy storage module in real time;

the control module is used for controlling the discharge MOS to be disconnected when the current detection circuit detects that the power supply current is larger than a preset current value under the condition that the discharge MOS is triggered to be started, and judging whether the load is short-circuited or not according to the currently detected voltage of the load and the voltage of the load before the discharge MOS is triggered to be started so as to prevent false short-circuit protection. The voltage at two ends of the load is collected before the load is powered as initial voltage, and then the discharging MOS is controlled to be conducted, so that when the short circuit occurs in the primary judging circuit with overlarge power supply current, the discharging MOS is controlled to be disconnected and the current voltage at two ends of the load is collected, and whether the short circuit actually occurs in the circuit can be accurately judged when the load is a capacitive load or a resistive load by calculating the difference value between the current voltage and the initial voltage, and therefore the circuit is accurately short-circuit protected in the power supply process.

Further, the current detection circuit comprises a resistor branch and a comparator, one end of the resistor branch is electrically connected with the negative electrode of the energy storage module, the other end of the resistor branch is electrically connected with the source electrode of the discharge MOS, the other end of the resistor branch is electrically connected with the electrical connection point of the discharge MOS, the positive input end of the comparator is electrically connected with the negative input end of the comparator, the negative input end of the comparator is used for inputting reference voltage, and the output end of the comparator is electrically connected with the control module.

Further, the control module is used for controlling the discharge MOS to be disconnected when the comparator outputs a high level.

In addition, a short-circuit protection method of the battery management system is provided, the method is realized based on the short-circuit protection device of the battery management system, and the method comprises the following steps:

before an energy storage module supplies power to a load, acquiring voltages at two ends of the load to obtain a first voltage;

controlling a discharging MOS to be closed so as to enable the energy storage module to supply power to the load;

when the current detection circuit detects that the power supply current of the energy storage module is larger than a preset current value, the discharge MOS is controlled to be disconnected;

obtaining the voltage at two ends of the load to obtain a second voltage;

judging whether the load is short-circuited according to the first voltage and the second voltage so as to avoid the influence of error short-circuit protection on the normal power supply process of the load.

Further, the control of the discharge MOS turn-off previously includes:

the time is delayed by a first preset time period,

the first preset time is determined according to the charging time of the capacitive load in the load.

Further, obtaining the voltage across the load to obtain the second voltage includes:

the time is delayed for a second preset time period,

so that the second voltage detected by the voltage detection circuit can be maintained in a stable state.

Further, judging whether the load is short-circuited according to the first voltage and the second voltage to avoid the influence of error short-circuit protection on the normal power supply process of the load, including:

obtaining a voltage variation value according to the first voltage and the second voltage;

comparing the voltage variation value with a preset voltage difference;

when the voltage change value is greater than or equal to the preset voltage difference, judging that the load is not short-circuited, controlling the discharge MOS to be closed, and simultaneously stopping responding to a signal sent by the current detection circuit, so as to avoid the influence of error short-circuit protection on the normal power supply process of the load. Through collocation setting up current detection circuit and control module for when supply current is too big in the circuit, can accurately report overcurrent information to control module, make control module can judge whether the overcurrent information that reports is short-circuit protection misinformation through the state combination of control discharge MOS in the load both ends that gathers under corresponding state, so that can guarantee when confirming to be short-circuit protection misinformation that control module does not respond current detection circuit's reporting information, thereby carry out normal power supply process.

Further, when the load is a combination of a capacitive load and a resistive load, the preset voltage difference is set according to the voltage across the resistive load.

Further, comparing the voltage variation value with a preset voltage difference, and then includes:

and when the voltage variation value is smaller than the preset voltage difference, judging that the load is short-circuited.

Further, when the voltage variation value is smaller than the preset voltage difference, determining that the load is shorted, and then includes:

when the load is judged to have a short circuit, the first voltage and the second voltage are circularly acquired;

judging whether the load is short-circuited or not according to the first voltage and the second voltage which correspond to each time;

and when the times of short circuit occurrence of the load exceeds the preset times, finally judging that the load is short-circuited.

As described above, the invention has the following beneficial effects:

1) The voltage at two ends of the load is collected before the load is powered as initial voltage, and then the discharging MOS is controlled to be conducted, so that when the short circuit occurs in the primary judging circuit with overlarge power supply current, the discharging MOS is controlled to be disconnected and the current voltage at two ends of the load is collected, and whether the short circuit actually occurs in the circuit can be accurately judged when the load is a capacitive load or a resistive load by calculating the difference value between the current voltage and the initial voltage, and therefore the circuit is accurately short-circuit protected in the power supply process.

2) Through collocation setting up current detection circuit and control module for when supply current is too big in the circuit, can accurately report overcurrent information to control module, make control module can judge whether the overcurrent information that reports is short-circuit protection misinformation through the state combination of control discharge MOS in the load both ends that gathers under corresponding state, so that can guarantee when confirming to be short-circuit protection misinformation that control module does not respond current detection circuit's reporting information, thereby carry out normal power supply process.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the following description will make a brief introduction to the drawings used in the description of the embodiments or the prior art. It should be apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained from these drawings without inventive effort to those of ordinary skill in the art.

Fig. 1 is a schematic diagram of a short-circuit protection device of a battery management system according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a prior art short circuit detection using a precharge mode;

FIG. 3 is a schematic diagram of the connection between a load composed of capacitive loads and a precharge resistor;

fig. 4 is a PWM waveform diagram for implementing precharge control provided in the prior art;

FIG. 5 is a graph of the real-time voltage across a load consisting of a capacitive load during a precharge process;

FIG. 6 is a schematic diagram of a prior art connection between a load and a precharge resistor formed by a combination of a capacitive load and a resistive load;

FIG. 7 is a schematic diagram showing a connection relationship between a load formed by combining a capacitive load and a resistive load and a resistor in a power supply loop according to an embodiment of the present disclosure;

FIG. 8 is a graph of real-time voltage across a load made up of a combination of capacitive and resistive loads according to an embodiment of the present disclosure;

fig. 9 is a flowchart of a short circuit method of a battery management system according to an embodiment of the present disclosure.

Wherein, the reference numerals in the figures correspond to:

the device comprises an energy storage module 1, a discharging MOS2, a charging MOS3, a load 4, a voltage detection circuit 5, a current detection circuit 6, a resistor branch 61 and a control module 7.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Example 1:

as shown in fig. 1, an embodiment of the present disclosure provides a short circuit protection device of a battery management system, including:

the energy storage device comprises an energy storage module 1, a discharging MOS2 and a charging MOS3, wherein the positive end of the energy storage module 1 is used for being electrically connected with one end of a load 4, and the negative end of the energy storage module 1 is electrically connected with the other end of the load 4 after being sequentially connected with the discharging MOS2 and the charging MOS3 in series;

a voltage detection circuit 5, the voltage detection circuit 5 being electrically connected to both ends of the load 4, the voltage detection circuit 5 being configured to detect a voltage of the load 4;

the current detection circuit 6 is used for monitoring the power supply current of the energy storage module 1 in real time;

the control module 7, the voltage detection circuit 5, the current detection circuit 6 and the discharge MOS2 are all electrically connected with the control module 7, and the control module 7 is used for controlling the discharge MOS2 to be disconnected when the current detection circuit 6 detects that the power supply current is larger than a preset current value under the condition that the discharge MOS2 is triggered to be started, and judging whether the load 4 is short-circuited or not according to the currently detected voltage of the load 4 and the voltage of the load 4 before the discharge MOS2 is triggered to be started so as to prevent the false short-circuit protection phenomenon. In this embodiment, the control module 7 is an MCU.

Specifically, the discharging MOS2 and the charging MOS3 are NMOS tubes, the source electrode of the discharging MOS2 is electrically connected with the negative end B-of the energy storage module 1, the drain electrode of the discharging MOS2 is electrically connected with the drain electrode of the charging MOS3, the source electrode of the charging MOS3 is electrically connected with the negative end P-of the load 4, the grid electrode of the discharging MOS2 and the grid electrode of the charging MOS3 are electrically connected with the control module 7, and the positive end P+ of the load 4 is electrically connected with the positive end B+ of the energy storage module 1.

Wherein, the control module 7 continuously outputs a high level to the gate of the charging MOS3 to control the charging MOS3 to maintain the on state.

As shown in fig. 2, in the current short circuit detection method for a load before power supply, it is common to determine by using a pre-charge circuit based on a delay determination method, and charge the load by using the pre-charge circuit to solve the problem of false alarm of a short circuit of a capacitive load, but the method is not applicable to a load with a load type of combination of a capacitive load and a resistive load, for the following reasons:

when the precharge mode is applied to the load type as the capacitive load, the short circuit judgment process is as follows:

as shown in fig. 3, in the case where the energy storage module supplies power to the capacitive load, the capacitive load is the capacitor shown in fig. 3, and the resistor in fig. 3 is the precharge resistor in the precharge circuit.

The power-on mode of the precharge circuit is controlled as shown in fig. 4, i.e., the precharge circuit is controlled to be turned on and off by a PWM wave of a set period. As shown in fig. 5, the capacitor is charged in time periods by periodically controlling the on/off of the pre-charging circuit, so as to achieve the time-period rising of the capacitor voltage, so that the voltages at two ends of the capacitor can be collected at the time point corresponding to a certain state of the capacitor charging or after the charging is completed.

When the collected voltages at the two ends of the capacitor exceed the preset voltage value, the current load can be directly judged to be a capacitive load and no short circuit phenomenon occurs, and when the load is short-circuited, the voltage at the two ends of the capacitor is detected to be zero or the voltage value is very low, so that the current load can be directly judged to be short-circuited. And the problem of capacitive load false alarm can be solved on the basis of combining a delay judgment method.

When the precharge mode is applied to the combination of the load type of capacitive load and resistive load, the short circuit judgment process is as follows:

as shown in fig. 6, in the scenario that the energy storage module supplies the load of the sum of the capacitive load and the resistive load, the capacitive load is the capacitance shown in fig. 6, and the resistance connected in parallel with the capacitive load in fig. 6 is the resistive load in the current load; the resistance in series with the current load in fig. 6 is the precharge resistance in the precharge circuit.

The power-on mode of the precharge circuit is controlled as shown in fig. 4, i.e., the precharge circuit is controlled to be turned on and off by a PWM wave of a set period. Because the capacitive load in the load is connected with the resistive load in parallel, the voltage at two ends of the energy storage module can be divided by the resistive load and the pre-charging resistor under the action of the resistive load. The resistance of the pre-charging resistor is generally hundreds of ohms and is far greater than that of the resistive load, so that the voltage at two ends of the resistive load in the load after voltage division is too small.

In the opening and disconnection control process of the pre-charging circuit, after the capacitor is charged to a corresponding time point of a certain state or the charging is finished, the voltages at two ends of the collected load are too small, and likewise, when the load is short, the voltages at two ends of the load are too small, so that whether the current load is short-circuited cannot be directly judged according to the collected voltages at two ends of the load, the pre-charging mode of the pre-charging circuit can be invalid due to the resistive load in the load, and therefore, even on the basis of a combined delay judgment method, whether the current load is a capacitive load and short-circuited is not judged when the short-circuited is reported, or the current load type is the combination of the capacitive load and the resistive load is not judged.

Therefore, the method adopts a mode of controlling the switching of the discharging MOS and the voltage detection circuit to carry out voltage acquisition on the load twice to carry out short circuit judgment on the load with the load type of combination of capacitive load and resistive load. The method comprises the steps of collecting voltages at two ends of a load before supplying power to the load as initial voltages, controlling the discharge MOS to be conducted, triggering the MCU to control the discharge MOS to be disconnected when detecting that a short circuit occurs in a primary judging circuit with overlarge power supply current, collecting the current voltages at two ends of the load, and further comparing the current voltages with the initial voltages to accurately judge whether the current load is truly short-circuited or not, so that short-circuit protection is accurately performed on the circuit in the power supply process.

Preferably, the current detection circuit 6 includes a resistor branch 61 and a comparator, one end of the resistor branch 61 is electrically connected with the negative electrode of the energy storage module 1, the other end is electrically connected with the source electrode of the discharging MOS2, the other end is electrically connected with the electrical connection point of the discharging MOS2 and the positive input end of the comparator, the negative input end of the comparator is used for inputting a reference voltage, and the output end is electrically connected with the control module 7.

Preferably, the control module 7 is configured to control the discharge MOS2 to be turned off when the comparator outputs a high level.

Specifically, the positive input end of the comparator is electrically connected with the electrical connection point of the resistor branch 61 and the discharging MOS2, so that a voltage drop is generated at two ends of the resistor branch 61 when a current flows in the circuit, when the voltage drop exceeds a reference voltage, a high level is output to the MCU, and the MCU determines that the current in the circuit exceeds a preset current at the moment and a short circuit occurs to a circuit load. However, since the load type of the load 4 is not determined, the overcurrent phenomenon in the circuit cannot be guaranteed due to the fact that the short circuit condition actually occurs, and accurate confirmation is needed.

Therefore, the present application collects the voltage across the load 4 as the initial voltage before supplying power to the load 4, and then outputs a high level to the discharge MOS2 through the control module 7 to turn on the discharge MOS2, and at this time, the energy storage module 1 supplies power to the load 4. The short supply at this time is for realizing the short circuit detection function.

In general, when the voltage drop of the supply current in the circuit on the resistor branch 61 does not exceed the reference voltage, the comparator continuously outputs a low level to the MCU, and no short-circuit information is reported to the MCU.

When the voltage drop generated by the supply current in the circuit on the resistor branch 61 exceeds the reference voltage, the comparator outputs a high level to the MCU, and the MCU judges that the current loop is short-circuited. The short circuit information reported by the comparator may be caused by the load which is a combination of capacitive load and resistive load.

Therefore, after the MCU receives the short-circuit information reported by the comparator, the MCU outputs a low level to the discharge MOS2 after a period of time delay to control the discharge MOS2 to be turned off, and the voltage detection circuit 5 is used to collect the voltages at two ends of the load 4 for the second time, when the voltage difference between the obtained voltage and the initial voltage is greater than the preset voltage difference, the load type of the load 4 is determined to be the combination type of the capacitive load and the resistive load, and no short circuit occurs in the current loop, the short-circuit information reported by the comparator is a short-circuit false report, at this time, the MCU will not respond to the signal sent by the comparator any more, and meanwhile, control the discharge MOS2 to be continuously turned on, so as to continuously supply power to the load 4 to enter the normal power supply process.

The delay time before the voltage detection circuit 5 collects the voltages across the load 4, i.e. the first preset time, can be set by a person skilled in the art. The first preset time is generally set to 0 to 300ms.

The first preset time may also be determined according to the load type of the load 4 and related technical parameters in the load 4.

As shown in fig. 1, 7 and 8, when the load 4 is a combination of a capacitive load and a resistive load, that is, includes a capacitive load and a resistive load connected in parallel, the voltage of the energy storage module 1 is calculated by using a voltage dividing principle according to the resistance value in the power supply loop and the resistance value of the resistive load connected in parallel with the capacitive load, so as to obtain the voltage division of the resistive load.

And determining the time from the filling of the capacitive load to the partial pressure in the load 4, and setting the acquisition time point of the voltage at the two ends of the load 4 for the second time by combining the time point of the initial voltage acquisition, namely setting the time delay between the two acquisition time points to be larger than the time from the filling to the partial pressure.

For example, as shown in fig. 7 and 8, r1=5Ω, r2=50Ω, and Vbat is 60V, where R1 is a resistive load in the load 4, the equivalent resistance in the R2 power supply loop, vbat is the voltage across the energy storage module 1, V1 is the first voltage in the present application, V2 is the second voltage in the present application, and the first preset time is t2-t1. The equivalent resistance is the sum of three resistance values of the resistance branch 61 in the current detection circuit 6, and the internal resistances of the discharging MOS2 and the charging MOS 3.

V2= (vbat×r1)/(r1+r2) =5.5V, the preset voltage difference is V2-V1, since the default V1 is generally close to 0V, and thus the preset voltage difference V2-V1 is close to V2, i.e., approximately equal to 5.5V. Thus, the preset voltage difference may be set to 5.5V, or slightly less than 5.5V, on the basis that the first preset time satisfies the time from the capacitive load filling up to said partial pressure in the load 4.

Specifically, in this embodiment, after the MCU controls the discharge MOS2 to be turned off, a delay time, that is, a second preset time, may be set to enable the voltages at two ends of the load 4 to be kept within a stable interval, so that the voltage acquisition performed on the load 4 for the second time is more accurate. Wherein, the second preset time is t3-t2 in fig. 8.

The delay time of the MCU control discharge MOS2 is smaller than the delay time of the MCU control discharge MOS2 before the disconnection.

As shown in fig. 9, the embodiment of the present specification provides a short-circuit protection method of a battery management system, which is implemented based on the short-circuit protection device of the battery management system in embodiment 1, including:

s100: before the energy storage module 1 supplies power to the load 4, acquiring voltages at two ends of the load 4 to obtain a first voltage;

s200: controlling a discharging MOS2 to be closed so that the energy storage module 1 supplies power to the load 4;

s300: when the current detection circuit 6 detects that the power supply current of the energy storage module 1 is larger than a preset current value, the discharge MOS2 is controlled to be disconnected;

s400: obtaining the voltage at two ends of the load 4 to obtain a second voltage;

s500: judging whether the load 4 is short-circuited according to the first voltage and the second voltage so as to avoid the influence of error short-circuit protection on the normal power supply process of the load 4.

The first voltage is an initial voltage obtained by collecting voltages at two ends of the load 4 before supplying power to the load 4; the second voltage is a voltage value acquired for the current voltage at the two ends of the load 4 after the MCU is triggered to control the discharge MOS2 to be disconnected.

In a specific embodiment, the control discharge MOS2 is turned off, before comprising:

the time is delayed by a first preset time period,

wherein the first preset time is determined according to the charging time of the capacitive load in the load 4.

Specifically, the first preset time is the charging time of the capacitive load in the load 4 or the product of the charging time and a preset percentage.

In a specific embodiment, step S400 includes obtaining the voltage across the load 4 to obtain the second voltage, which includes:

the time is delayed for a second preset time period,

so that the second voltage detected by the voltage detection circuit 5 can be maintained in a stable state.

In a specific embodiment, step S500 judges whether the load 4 is shorted according to the first voltage and the second voltage, so as to avoid performing error short protection to affect a normal power supply process to the load 4, including:

comparing the voltage variation value with a preset voltage difference;

when the voltage variation value is greater than or equal to the preset voltage difference, it is determined that the load 4 is not shorted and the discharging MOS2 is controlled to be closed, and signals sent by the current detection circuit 6 are stopped, so that the influence of error short-circuit protection on the normal power supply process of the load 4 is avoided.

When the load 4 is a combination of a capacitive load and a resistive load, the preset voltage difference is set according to the voltages at two ends of the resistive load.

Specifically, the first voltage is an initial voltage of the load 4 when the energy storage module 1 does not supply the load 4, that is, a voltage generated by the load 4 in the self device, and may be obtained through estimation or measurement.

In this embodiment, the preset voltage difference is set according to the stable voltage value of the two ends of the load 4 after the capacitive load in the load 4 is charged, under the condition of considering the initial voltage, and the sum of the initial voltage and the preset voltage difference is ensured to be smaller than the stable voltage value.

In general, when the load 4 is a capacitive load and a resistive load connected in parallel, the default initial voltage is 0V, and after the capacitive load is fully charged, a second voltage with a stable voltage value is obtained after a second preset time delay, and at this time, the collected second voltage is a voltage that is close to or equal to the voltage division of the resistive load on the energy storage module 1, so that the preset voltage difference is set to be the voltage value of the resistive load voltage division or slightly less than the voltage value of the resistive load voltage division, and it can be determined that the load 4 has no short circuit when the difference between the second voltage and the first voltage is greater than or equal to the preset voltage difference.

The voltage division of the resistive load is determined according to the proportional relation between the resistance of the resistive load and the resistance in the power supply loop and the voltage of the energy storage module 1, and the resistance in the power supply loop comprises the sum of the three resistances of the resistance of the resistor branch 61, the internal resistances of the discharging MOS2 and the charging MOS3 in the current detection circuit 6.

Therefore, no matter under the condition that the load type is a combination of a capacitive load and a resistive load, the second voltage with a larger difference from the first voltage can be acquired after delaying for the first preset time, so that whether the load 4 is short-circuited or not can be accurately judged.

It should be noted that, in general, when the short circuit detection is performed on the load 4, the load type of the load 4 is uncertain, and the preset voltage difference is set to be a resistive load partial voltage or a voltage value slightly smaller than the resistive load partial voltage, which can be applied to the short circuit detection process of the capacitive load or the combination of the capacitive load and the resistive load.

In a specific embodiment, comparing the voltage variation value with a preset voltage difference includes:

and when the voltage variation value is smaller than the preset voltage difference, judging that the load 4 is short-circuited.

In a specific embodiment, when the voltage variation value is smaller than the preset voltage difference, determining that the load 4 is shorted, then includes:

when it is determined that the load 4 is short-circuited, the first voltage and the second voltage are cyclically acquired;

judging whether the load 4 is short-circuited or not according to the first voltage and the second voltage corresponding to each time;

when the number of times of short circuit occurrence of the load 4 is determined to exceed the preset number of times, the load 4 is finally determined to be short-circuited.

While the invention has been described in terms of preferred embodiments, the invention is not limited to the embodiments described herein, but encompasses various changes and modifications that may be made without departing from the scope of the invention.

The embodiments and features of the embodiments described herein can be combined with each other without conflict.

The above disclosure is only a preferred embodiment of the present invention, and it is needless to say that the scope of the invention is not limited thereto, and therefore, the equivalent changes according to the claims of the present invention still fall within the scope of the present invention.

Claims

1. A short circuit protection device of a battery management system, comprising:

the energy storage device comprises an energy storage module (1), a discharging MOS (2) and a charging MOS (3), wherein the positive end of the energy storage module (1) is used for being electrically connected with one end of a load (4), and the negative end of the energy storage module (1) is electrically connected with the other end of the load (4) after being sequentially connected with the discharging MOS (2) and the charging MOS (3) in series;

a voltage detection circuit (5), wherein the voltage detection circuit (5) is electrically connected to two ends of the load (4), and the voltage detection circuit (5) is used for detecting the voltage of the load (4);

the current detection circuit (6) is used for monitoring the power supply current of the energy storage module (1) in real time;

the control module (7), voltage detection circuit (5), current detection circuit (6) with discharge MOS (2) all with control module (7) electricity is connected, control module (7) are used for when trigger under the condition that discharge MOS (2) are opened current detection circuit (6) detects when power supply current is greater than preset current value control discharge MOS (2) disconnection just according to the voltage of load (4) that detects at present and trigger discharge MOS (2) before opening the voltage of load (4) judges whether load (4) appears the short circuit.

2. The short-circuit protection device of a battery management system according to claim 1, wherein the current detection circuit (6) comprises a resistor branch (61) and a comparator, one end of the resistor branch (61) is electrically connected with the negative electrode of the energy storage module (1), the other end of the resistor branch is electrically connected with the source electrode of the discharging MOS (2), the other end of the resistor branch is electrically connected with the electrical connection point of the discharging MOS (2) and the positive input end of the comparator, the negative input end of the comparator is used for inputting a reference voltage, and the output end of the comparator is electrically connected with the control module (7).

3. The short-circuit protection device of a battery management system according to claim 2, characterized in that the control module (7) is adapted to control the discharge MOS (2) to be turned off when the comparator outputs a high level.

4. A short-circuit protection method of a battery management system, the method being implemented based on the short-circuit protection device of a battery management system according to any one of claims 1 to 3, comprising:

before an energy storage module (1) supplies power to a load (4), acquiring voltages at two ends of the load (4) to obtain a first voltage;

controlling a discharge MOS (2) to close so that the energy storage module (1) supplies the load (4);

when the current detection circuit (6) detects that the power supply current of the energy storage module (1) is larger than a preset current value, the discharge MOS (2) is controlled to be disconnected;

obtaining the voltage at two ends of the load (4) to obtain a second voltage;

judging whether the load (4) is short-circuited according to the first voltage and the second voltage so as to avoid the influence of error short-circuit protection on the normal power supply process of the load (4).

5. The short-circuit protection method of a battery management system according to claim 4, characterized in that the control of the discharge MOS (2) to be turned off previously comprises:

the time is delayed by a first preset time period,

wherein the first preset time is determined according to a charging time of a capacitive load in the load (4).

6. The short-circuit protection method of a battery management system according to claim 5, characterized in that the obtaining of the voltage across the load (4) to obtain the second voltage, previously comprises:

the time is delayed for a second preset time period,

so that the second voltage detected by the voltage detection circuit (5) can be maintained in a stable state.

7. The short-circuit protection method of a battery management system according to claim 6, wherein determining whether the load (4) is shorted according to the first voltage and the second voltage to avoid performing a false short-circuit protection to affect a normal power supply process to the load (4) comprises:

comparing the voltage variation value with a preset voltage difference;

when the voltage change value is larger than or equal to the preset voltage difference, judging that the load (4) is not short-circuited, controlling the discharge MOS (2) to be closed, and simultaneously stopping responding to a signal sent by the current detection circuit (6), so as to avoid the influence of error short-circuit protection on the normal power supply process of the load (4).

8. The short-circuit protection method of a battery management system according to claim 7, characterized in that when the load (4) is a combination of a capacitive load and a resistive load, the preset voltage difference is set according to the voltage across the resistive load.

9. The short circuit protection method of a battery management system according to claim 8, wherein comparing the voltage variation value with a preset voltage difference, after which comprises:

and when the voltage variation value is smaller than the preset voltage difference, judging that the load (4) is short-circuited.

10. The short-circuit protection method of a battery management system according to claim 9, wherein when the voltage variation value is smaller than the preset voltage difference, it is determined that the load (4) is short-circuited, and then comprising:

when it is determined that the load (4) has a short circuit, cyclically acquiring the first voltage and the second voltage;

judging whether the load (4) is short-circuited or not according to the first voltage and the second voltage which correspond to each time;

and when the times of short circuit of the load (4) exceeds the preset times, finally judging that the load (4) is short-circuited.