A vehicle-mounted low-voltage battery pack short circuit protection method, circuit and device

Abstract

The application relates to a vehicle-mounted low-voltage battery short-circuit protection method, circuit and device. The method detects the current direction, current value and multiple groups of cell voltage values of a vehicle-mounted low-voltage battery pack. When the current value is greater than a first preset current value and the current direction is in a discharging state, timing is started, and an overcurrent duration is obtained. A fuse time threshold is obtained. When the overcurrent duration is greater than the fuse time threshold, a discharge switch of the vehicle-mounted low-voltage battery pack is controlled to be turned off. When the overcurrent duration is less than the fuse time threshold, the discharge switch of the vehicle-mounted low-voltage battery pack is kept on. According to the overcurrent duration, whether the fuse functions is judged. If the fuse does not function, the discharge switch is controlled to be turned off, so that when the short-circuit protection of the battery pack for a single load functions, the discharge switch of the battery pack is still turned off, and the battery pack cannot supply power to other normal loads. The problem that the battery pack cannot supply power to other normal loads when the short-circuit protection is performed is solved.

Description

Technical Field

[0001] This invention relates to the field of vehicle battery safety technology, and in particular to a method, circuit, and device for short-circuit protection of a vehicle-mounted low-voltage battery pack. Background Technology

[0002] The booming development of the new energy vehicle industry has accelerated the popularization of autonomous driving technology. Autonomous driving technology relies on an onboard controller, whose reliable operation is a key factor in ensuring vehicle safety. Reliable controller operation depends on a reliable power supply design. Traditional power supply designs on the market use a 12V lead-acid battery and a 12V battery charger connected in parallel to power the controller. When an external short circuit occurs in the battery pack, if the battery pack cannot promptly identify and disconnect the discharge circuit, it may lead to overheating of the battery cells and thermal runaway. When an internal short circuit occurs in the battery pack, the 12V battery charger may not be able to simultaneously charge the battery and power other electrical appliances on the grid, potentially causing the controller to malfunction due to undervoltage, thus affecting driving safety.

[0003] Currently, 12V battery systems for lithium batteries on the market typically use relays as battery circuit breakers. However, relays often have a delay of tens of milliseconds during the shutdown process and there are inconsistency issues. Furthermore, in the application scenario of vehicle 12V power networks, since there are multiple electrical appliances on this power network, if a short circuit occurs in one of the electrical appliances during vehicle operation, the 12V lithium battery will choose to disconnect the battery circuit breaker as soon as it detects that the discharge current exceeds the set threshold. This can cause the vehicle 12V battery pack to disconnect from the power grid due to a short circuit inside a single electrical appliance, making it unable to supply power to the grid normally. Summary of the Invention

[0004] In view of this, it is necessary to provide a method, circuit and device for short circuit protection of vehicle low-voltage battery packs to solve the technical problem that existing vehicle low-voltage battery packs cannot supply power to other normal loads when performing short circuit protection.

[0005] To address the above problems, this invention provides a short-circuit protection method for a vehicle-mounted low-voltage battery pack, comprising:

[0006] Detects the current direction, current value, and multiple cell voltage values ​​of the vehicle's low-voltage battery pack;

[0007] The overcurrent duration is obtained by starting the timing when the current value is greater than the first preset current value and the current direction is in the direction of discharge.

[0008] Obtain the circuit breaker time threshold;

[0009] When the overcurrent duration exceeds the fuse time threshold, the discharge switch of the vehicle low-voltage battery pack is controlled to open.

[0010] When the overcurrent duration is less than the fuse time threshold, the discharge switch of the vehicle low-voltage battery pack remains closed.

[0011] Optionally, after starting the timer when the current value is greater than a first preset current value and the current direction is in the direction of discharge, and obtaining the overcurrent duration, the process includes:

[0012] The timing stops and the overcurrent duration is reset when the current value is less than the first preset current value or when the current direction is in the charging state.

[0013] Optionally, after the discharge switch of the vehicle low-voltage battery pack is opened when the overcurrent duration is greater than the fuse time threshold, the following steps are taken:

[0014] When the current direction is in the charging state and the current value is greater than a second preset current value, the charging switch of the vehicle low-voltage battery pack is controlled to be turned off.

[0015] Optionally, after detecting the current direction, current value, and cell voltage value of the vehicle-mounted low-voltage battery pack, the process includes:

[0016] When the current value is greater than a third preset current value and the cell voltage value is less than a preset voltage threshold, the charging switch of the vehicle low-voltage battery pack is controlled to be disconnected.

[0017] When the current direction is in the discharge state and the current value is greater than a fourth preset current value, the discharge switch of the vehicle low-voltage battery pack is controlled to open.

[0018] Optionally, when the current value is greater than a third preset current value and the cell voltage value is less than a preset voltage threshold, the charging switch of the vehicle low-voltage battery pack is controlled to be disconnected, including:

[0019] When the current value is greater than the third preset current value and the cell voltage value is less than the preset voltage threshold, an internal short circuit fault alarm is triggered and an internal short circuit fault timer is started.

[0020] When the timeout period for the internal short circuit fault exceeds a preset time threshold, the charging switch of the vehicle low-voltage battery pack is disconnected.

[0021] Optionally, before controlling the charging switch of the vehicle low-voltage battery pack to disconnect when the internal short-circuit fault time exceeds a preset time threshold, the following steps are included:

[0022] When the cell voltage is less than the minimum voltage threshold, the charging switch of the vehicle low-voltage battery pack is turned off.

[0023] Furthermore, the present invention also provides a short-circuit protection circuit for an on-board low-voltage battery pack, used to implement the above-mentioned short-circuit protection method for an on-board low-voltage battery pack. The circuit includes a battery pack, a switching module, a current detection module, and multiple fuses.

[0024] The multiple fuses are connected in parallel, and one fuse is connected in series with one load. The battery pack, the switch module, the module consisting of the multiple fuses and the load, and the current detection module are connected in series in sequence.

[0025] The battery pack is used to provide electrical energy to the load and to receive electrical energy transmitted from an external power source;

[0026] The switching module is used to control the opening and closing of the charging circuit and the discharging circuit;

[0027] The current detection module is used to detect the current direction and current value;

[0028] The fuse is used for overcurrent protection.

[0029] Optionally, the switching module includes a first MOS switch for controlling the discharge circuit and a second MOS switch for controlling the charging circuit;

[0030] The source of the first MOS switch is connected to the source of the second MOS switch, the drain of the first MOS switch is connected to the positive terminal of the battery pack, the drain of the second MOS switch is connected to the plurality of fuses, and the gates of the first MOS switch and the second MOS switch are both connected to the vehicle BMS controller.

[0031] Optionally, the detection module is a splitter.

[0032] Furthermore, the present invention also provides a vehicle-mounted low-voltage battery pack short-circuit protection device, including a BMS system and the above-mentioned vehicle-mounted low-voltage battery pack short-circuit protection circuit.

[0033] The beneficial effects of the above embodiments are as follows: The vehicle-mounted low-voltage battery short-circuit protection method provided by the present invention detects the current direction, current value, and multiple cell voltage values ​​of the vehicle-mounted low-voltage battery pack; when the current value is greater than a first preset current value and the current direction is in the discharge state, timing begins to obtain the overcurrent duration; a fusing time threshold is obtained; when the overcurrent duration is greater than the fusing time threshold, the discharge switch of the vehicle-mounted low-voltage battery pack is controlled to open; when the overcurrent duration is less than the fusing time threshold, the discharge switch of the vehicle-mounted low-voltage battery pack remains closed. The present invention determines whether the battery pack's short-circuit protection is effective based on the overcurrent duration. If it is not effective, the single-point switch is controlled to open, avoiding the situation where the battery pack's discharge switch remains open even when the short-circuit protection for a single load is effective, preventing power supply to other normal loads. This solves the technical problem that existing vehicle-mounted low-voltage battery packs cannot supply power to other normal loads when performing short-circuit protection. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A flowchart illustrating an embodiment of the vehicle-mounted low-voltage battery pack short-circuit protection method provided by the present invention;

[0036] Figure 2 This is a flowchart illustrating an embodiment of the short-circuit protection method for vehicle-mounted low-voltage battery packs provided by the present invention, following step S101.

[0037] Figure 3 This is a flowchart illustrating an embodiment of the short-circuit protection method for vehicle-mounted low-voltage battery packs provided by the present invention, following step S201.

[0038] Figure 4 This is a schematic diagram of an embodiment of the vehicle-mounted low-voltage battery pack short-circuit protection circuit provided by the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] It should be understood that the illustrative drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the invention. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or performed simultaneously. Furthermore, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] This invention provides a method, circuit, and device for short-circuit protection of a vehicle-mounted low-voltage battery pack, which will be described below.

[0043] Figure 1 This is a flowchart illustrating an embodiment of the vehicle-mounted low-voltage battery pack short-circuit protection method provided by the present invention, as shown below. Figure 1 As shown, it includes:

[0044] S101. Detect the current direction, current value, and multiple cell voltage values ​​of the vehicle's low-voltage battery pack.

[0045] S102, When the current value is greater than the first preset current value and the current direction is in the direction of discharge, start timing to obtain the overcurrent duration;

[0046] S103. Obtain the circuit breaker time threshold;

[0047] S104. When the overcurrent duration is greater than the fuse time threshold, control the discharge switch of the vehicle low-voltage battery pack to be disconnected.

[0048] S105. When the overcurrent duration is less than the fuse time threshold, keep the discharge switch of the vehicle low-voltage battery pack closed.

[0049] It should be noted that, in this embodiment of the invention, the short-circuit protection circuit can be implemented using an on-board BMS system. A current sensor detects the total input and output current value (i.e., current direction) of the on-board low-voltage battery pack, and a voltage sensor detects the voltage value of each individual cell in the battery pack. Based on the current direction, it can be determined whether the battery pack is in a charging or discharging state. When the battery pack is in a discharging state and the detected current value is greater than a first preset current value (i.e., the maximum allowable discharge current value corresponding to the battery pack), it indicates a short circuit in the load. At this time, it is determined whether the overcurrent duration is greater than the fuse blowing time threshold (i.e., the maximum allowable blowing time of the fuse). If it is greater than the fuse blowing time threshold, it indicates that the fuse has not blown normally for short-circuit protection. Therefore, the on-board BMS system needs to control the battery pack's discharge switch to open for short-circuit protection. If it is less than the fuse blowing time threshold, it indicates that the fuse corresponding to the load has blown normally, providing targeted short-circuit protection for the load. The discharge switch remains closed, without cutting off all discharge circuits of the battery pack, ensuring that the battery pack will not be unable to supply power to other normal loads due to a short circuit in one load under normal circumstances.

[0050] Compared with existing technologies, the short-circuit protection method for vehicle-mounted low-voltage battery packs provided by this invention detects the current direction, current value, and multiple cell voltage values ​​of the vehicle-mounted low-voltage battery pack; starts timing when the current value is greater than a first preset current value and the current direction is in the discharge state, obtaining the overcurrent duration; acquires a fusing time threshold; controls the battery pack's discharge switch to open when the overcurrent duration is greater than the fusing time threshold; and keeps the battery pack's discharge switch closed when the overcurrent duration is less than the fusing time threshold. This invention determines whether the battery pack's short-circuit protection is effective based on the overcurrent duration; if it is ineffective, it controls the single-point switch to open, avoiding the situation where the battery pack's discharge switch remains open even when the short-circuit protection for a single load is effective, preventing power supply to other normal loads. This solves the technical problem of existing vehicle-mounted low-voltage battery packs being unable to supply power to other normal loads during short-circuit protection.

[0051] In some embodiments of the present invention, after step S102, the following is included:

[0052] The timing stops and the overcurrent duration is reset when the current value is less than the first preset current value or when the current direction is in the charging state.

[0053] It is understood that in this embodiment of the invention, the vehicle BMS system will start timing every time the current value is greater than the first preset current value. When the current value drops to below the first preset current value (indicating that the battery short circuit problem has been resolved and the battery pack discharge circuit has returned to normal operation), the overcurrent duration obtained by timing needs to be cleared to avoid repeated timing causing the discharge switch to malfunction.

[0054] In some embodiments of the present invention, after step S104, the following is included:

[0055] When the current direction is in the charging state and the current value is greater than a second preset current value, the charging switch of the battery pack is controlled to be turned off.

[0056] It is understood that, in this embodiment of the invention, since the discharge switch and the charging switch can be implemented using MOSFETs, disconnecting the discharge switch only cuts off the discharge circuit of the battery pack, while the charging circuit of the battery pack remains open, thus allowing the battery pack to be charged. However, the charging current is limited by the body diode of the discharge switch, meaning the charging current cannot exceed the maximum current that the body diode can carry. When the charging current exceeds the current limit (i.e., the second preset current), the charging switch is disconnected by the BMS system to stop charging, thereby protecting the body diode of the discharge switch.

[0057] In some embodiments of the present invention, reference is made to... Figure 2 , Figure 2 This is a flowchart illustrating an embodiment of the vehicle-mounted low-voltage battery pack short-circuit protection method provided by the present invention after step S101. After step S101, the method includes:

[0058] S201. When the current value is greater than the third preset current value and the cell voltage value is less than the preset voltage threshold, control the charging switch of the battery pack to be turned off.

[0059] S202. When the current direction is in the discharge state and the current value is greater than the fourth preset current value, the discharge switch of the battery pack is controlled to be turned off.

[0060] It is understood that, in this embodiment of the invention, the voltage value of each individual cell in the battery pack can also be detected by a voltage sensor. If the voltage value of a cell in the battery pack is less than a preset voltage threshold, which can be set to a voltage value that is 500mV lower than the average individual cell voltage value of the entire pack, and the current value is greater than a third preset current value (the current threshold can be set according to the actual internal short circuit situation), it indicates that an internal short circuit has occurred in the battery pack. At this time, the charging switch of the battery pack should be disconnected by controlling the BMS system.

[0061] It should be noted that, in this embodiment of the invention, since both the charging switch and the discharging switch are MOSFET switches, the body diode of the charging switch can still serve as a channel for the battery pack to discharge after the charging switch is turned off. However, the current value that the body diode can withstand is not high. Therefore, it is necessary to limit the current and control the discharging switch to turn off when the current value is greater than the fourth preset current value (i.e., the maximum current value that the body diode can pass through), so as to notify the battery pack to discharge and protect the body diode of the charging switch.

[0062] Reference Figure 2 , Figure 3 This is a flowchart illustrating an embodiment of the vehicle-mounted low-voltage battery pack short-circuit protection method provided by the present invention after step S201. Step S201 includes:

[0063] S301. When the current value is greater than the third preset current value and the cell voltage value is less than the preset voltage threshold, an internal short circuit fault alarm is triggered and an internal short circuit fault timer is started.

[0064] S302. When the timeout period for the internal short circuit fault exceeds a preset time threshold, the charging switch of the vehicle low-voltage battery pack is turned off.

[0065] It is understood that in this embodiment of the invention, when the detected current value is greater than the third preset current value and the cell voltage value is less than the preset voltage threshold, an alarm is first issued to the user to indicate that the battery pack may have a fault. If the alarm is not automatically cleared within a preset time (preset time threshold) (i.e., the time for the internal short circuit fault is greater than the preset time threshold), the charging switch of the vehicle low-voltage battery pack is then controlled to be disconnected. Since there may be voltage fluctuations in the cells inside the battery pack, this can prevent the charging switch from being accidentally disconnected.

[0066] In some embodiments of the present invention, before step S302, the following is included:

[0067] When the cell voltage is less than the minimum voltage threshold, the charging switch of the vehicle low-voltage battery pack is turned off.

[0068] It is understood that in this embodiment of the invention, a minimum voltage threshold can be set. When the cell voltage is lower than this minimum voltage threshold, it indicates that the battery pack is in a relatively dangerous state. At this time, there is no need to wait for the timer to be completed. The charging switch can be directly controlled to disconnect through the BMS system to protect the battery pack.

[0069] On the other hand, the present invention also provides a short-circuit protection circuit for an on-board low-voltage battery pack, used to implement the above-mentioned short-circuit protection method for an on-board low-voltage battery pack, as described above. Figure 4 , Figure 4 This is a schematic diagram of an embodiment of the vehicle-mounted low-voltage battery pack short-circuit protection circuit provided by the present invention. The circuit includes a battery pack 41, a switch module 42, a current detection module 43, and multiple fuses 44.

[0070] Among them, multiple fuses 44 are connected in parallel, one fuse F is connected in series with one load L, and the battery pack 41 and the switch module 42, the module composed of multiple fuses 44 and the load L and the current detection module 43 are connected in series in sequence.

[0071] The battery pack 41 is used to provide electrical energy to the load L and to receive electrical energy transmitted from the external power source G;

[0072] The switch module 42 is used to control the opening and closing of the charging circuit and the discharging circuit;

[0073] The current detection module 43 is used to detect the current direction and current value;

[0074] Fuse F is used for overcurrent protection.

[0075] Compared with the prior art, the embodiments of the present invention provide the first layer of protection against short circuits of external loads L through fuse F. This allows targeted short circuit protection to be provided by blowing the corresponding fuse F when a single external load L is short-circuited, without needing to disconnect the discharge switch. This allows the battery pack 41 to continue supplying power to other loads L. The current detection module 43 detects the current value and direction to determine whether the fuse F has successfully blown. If it has not successfully blown, the discharge switch is disconnected by the switch module 42 to cut off the discharge circuit, but the charging circuit is retained, allowing the battery pack 41 to continue charging. The embodiments of the present invention maximize the on-grid capability of the battery pack 41 while providing short-circuit protection.

[0076] In some embodiments of the present invention, the switching module 42 includes a first MOS switch S1 for controlling the discharge circuit and a second MOS switch S2 for controlling the charging circuit;

[0077] The source of the first MOS switch S1 is connected to the source of the second MOS switch S2, the drain of the first MOS switch S1 is connected to the positive terminal of the battery pack, the drain of the second MOS switch S2 is connected to multiple fuses 44, and the gates of the first MOS switch S1 and the second MOS switch S2 are both connected to the vehicle BMS controller.

[0078] It is understood that in this embodiment of the invention, two MOS switches are used as discharge switches and charging switches. By utilizing the characteristics of the body diode of the MOS switch, when the charging switch is open, discharge can be carried out through the body diode of the charging switch, and when the discharge switch is open, charging can be carried out through the body diode of the discharge switch. The BMS controller controls the conduction and closing of the charging switch and the discharge switch, thereby realizing the function of non-interference of charging and discharging short circuit protection, which greatly improves the on-grid capability of the battery pack.

[0079] In some embodiments of the present invention, the detection module is a splitter R.

[0080] It is understood that the embodiments of the present invention use a shunt R to detect the current value and direction of the battery pack.

[0081] It should be understood that a charger can be connected in parallel across the two ends of the battery pack to charge the battery pack or to supply power to a load.

[0082] On the other hand, the present invention also proposes a vehicle-mounted low-voltage battery pack short-circuit protection device, which includes a BMS system and the above-mentioned vehicle-mounted low-voltage battery pack short-circuit protection circuit.

[0083] It should be noted that the embodiments or specific implementations of the vehicle-mounted low-voltage battery pack short-circuit protection device of the present invention can refer to the embodiments of the low-voltage battery pack short-circuit protection circuit described above, and will not be repeated here.

[0084] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A short-circuit protection method for an on-board low-voltage battery pack, applied to an on-board low-voltage battery pack short-circuit protection circuit, the circuit comprising a battery pack, a switching module, a current detection module, and multiple fuses; wherein, The plurality of fuses are connected in parallel, with one fuse corresponding to one load in series. The battery pack, the switch module, the module consisting of the plurality of fuses and the load, and the current detection module are sequentially connected in series. The method is characterized by comprising: Detects the current direction, current value, and multiple cell voltage values ​​of the vehicle's low-voltage battery pack; The overcurrent duration is obtained by starting the timing when the current value is greater than the first preset current value and the current direction is in the direction of discharge. Obtain the fusing time threshold, wherein the fusing time threshold is the maximum allowable fusing time of the fuse; When the overcurrent duration exceeds the fuse time threshold, the discharge switch of the vehicle low-voltage battery pack is controlled to open. When the overcurrent duration is less than the fuse time threshold, the discharge switch of the vehicle low-voltage battery pack remains closed; Timing begins when the current value is greater than a first preset current value and the current direction is in the discharge state. After obtaining the overcurrent duration, the process includes: The timing stops and the overcurrent duration is reset when the current value is less than the first preset current value or when the current direction is in the charging state. When the overcurrent duration exceeds the fuse time threshold, after controlling the discharge switch of the vehicle low-voltage battery pack to open, the following steps are taken: When the current direction is in the charging state and the current value is greater than the second preset current value, the charging switch of the vehicle low-voltage battery pack is controlled to be turned off. After detecting the current direction, current value, and cell voltage value of the vehicle-mounted low-voltage battery pack, the process includes: When the current value is greater than a third preset current value and the cell voltage value is less than a preset voltage threshold, the charging switch of the vehicle low-voltage battery pack is controlled to be disconnected. When the current direction is in the discharge state and the current value is greater than the fourth preset current value, the discharge switch of the vehicle low-voltage battery pack is controlled to be disconnected. When the current value is greater than a third preset current value and the cell voltage value is less than a preset voltage threshold, the charging switch of the vehicle low-voltage battery pack is controlled to be disconnected, including: When the current value is greater than the third preset current value and the cell voltage value is less than the preset voltage threshold, an internal short circuit fault alarm is triggered and an internal short circuit fault timer is started. When the timeout period for the internal short circuit fault exceeds a preset time threshold, the charging switch of the vehicle low-voltage battery pack is disconnected.

2. The short-circuit protection method for vehicle-mounted low-voltage battery packs according to claim 1, characterized in that, Before the charging switch of the vehicle low-voltage battery pack is turned off when the internal short-circuit fault time exceeds a preset time threshold, the following steps are included: When the cell voltage is less than the minimum voltage threshold, the charging switch of the vehicle low-voltage battery pack is turned off.

3. A short-circuit protection circuit for a vehicle-mounted low-voltage battery pack, used to implement the short-circuit protection method for a vehicle-mounted low-voltage battery pack as described in any one of claims 1-2, characterized in that, The circuit includes a battery pack, a switching module, a current detection module, and multiple fuses; The multiple fuses are connected in parallel, and one fuse is connected in series with one load. The battery pack, the switch module, the module consisting of the multiple fuses and the load, and the current detection module are connected in series in sequence. The battery pack is used to provide electrical energy to the load and to receive electrical energy transmitted from an external power source; The switching module is used to control the opening and closing of the charging circuit and the discharging circuit; The current detection module is used to detect the current direction and current value; The fuse is used for overcurrent protection.

4. The vehicle-mounted low-voltage battery pack short-circuit protection circuit according to claim 3, characterized in that, The switching module includes a first MOS switch for controlling the discharge circuit and a second MOS switch for controlling the charging circuit; The source of the first MOS switch is connected to the source of the second MOS switch, the drain of the first MOS switch is connected to the positive terminal of the battery pack, the drain of the second MOS switch is connected to the plurality of fuses, and the gates of the first MOS switch and the second MOS switch are both connected to the vehicle BMS controller.

5. The on-board low-voltage battery pack short-circuit protection circuit according to claim 4, characterized in that, The current detection module is a shunt.

6. A short-circuit protection device for a vehicle-mounted low-voltage battery pack, characterized in that, This includes a BMS system and a vehicle-mounted low-voltage battery pack short-circuit protection circuit as described in any one of claims 3-5.

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