Charging and discharging safety control method and system of small power battery management system

Abstract

The invention provides a charging and discharging safety control method and system for a small-power battery management system, and relates to the technical field of battery management systems.The method comprises the steps that pre-discharging control is conducted, specifically, a battery and a load end are pre-discharged with pre-discharging current through a pre-discharging circuit composed of a controllable MOSFET and a current-limiting resistor, the voltage difference is reduced to be within a preset value, and the pre-discharging current of the battery and the load end is controlled; if the pre-discharge is overtime or the voltage difference is continuously greater than a preset value, determining that a short circuit occurs and triggering hard turn-off; dynamic key mutual recognition: the BMS generates a random number R1 and sends the random number R1 to the charger, the charger encrypts by using a preset key to generate a digital signature and returns the digital signature, and the BMS issues charging parameters after verifying the validity of the signature; multi-level fault response: executing power reduction, soft turn-off or hard turn-off operation according to the fault level; according to the invention, the voltage difference between the battery and the load end is eliminated through the pre-discharge circuit, an illegal charger is intercepted in combination with a dynamic key mutual recognition protocol, and rapid protection is realized by adopting a multi-stage fault response mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management systems (BMS), and specifically relates to a charge and discharge safety control method and system for a small power battery management system (BMS). Background Art

[0002] The existing battery management systems (BMS) for small power scenarios have the following technical defects:

[0003] 1. Hidden danger of discharge sparking: When the battery is connected to the load, arc discharge occurs due to excessive pressure difference, shortening the life of the connector and even causing safety accidents.

[0004] 2. Poor charger compatibility: Lack of a standardized mutual recognition protocol, illegal charger access is likely to cause problems such as overcharging and short - circuiting, and the existing technology only relies on one - way verification, with insufficient security.

[0005] 3. Lag in fault management: Traditional BMS only triggers protection actions through hardware thresholds, lacks active early warning and multi - level fault tolerance mechanisms, has low fault handling efficiency and cannot record abnormal logs.

[0006] The above problems restrict the safety and reliability of small power equipment, and there is an urgent need for a BMS solution that integrates active protection, intelligent authentication, and efficient management. Summary of the Invention

[0007] In view of this, in order to solve the defects of the existing small power BMS, such as discharge connection arcs, risks of illegal charger access, and low fault management efficiency, the purpose of the present invention is to propose a charge and discharge safety control method and system for a small power battery management system, which eliminates the pressure difference between the battery and the load end through a pre - discharge circuit, intercepts illegal chargers by combining a dynamic key mutual recognition protocol, and adopts a multi - level fault response mechanism to achieve rapid protection.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] Based on the above purpose, in the first aspect, the present invention provides a charge and discharge safety control method for a small power battery management system, including the following steps:

[0010] Pre - discharge control: Through a pre - discharge circuit composed of a controllable MOSFET and a current - limiting resistor, pre - discharge the battery and the load end with a pre - discharge current, reduce the pressure difference to within a preset value. If the pre - discharge times out or the pressure difference continuously exceeds the preset value, it is determined as a short - circuit and a hard shutdown is triggered;

[0011] Dynamic key mutual recognition: The BMS generates a random number R1 and sends it to the charger. The charger encrypts it using a preset key to generate a digital signature and returns it. After the BMS verifies the legality of the signature, it issues charging parameters;

[0012] Multi - level fault response: Perform power reduction, soft shutdown or hard shutdown operations according to the fault level;

[0013] Dynamic priority arbitration: When there is a conflict in charge - discharge requests, high - priority instructions are preferentially responded to according to the safety level of "fault shutdown > charging > discharging".

[0014] As a further solution of the present invention, the pre - discharge of the battery and the load terminal includes the following steps:

[0015] The pre - discharge current is a set value (such as 50 mA), and the duration is the pre - discharge control holding time (such as 20 ms);

[0016] If the pre - discharge times out or the voltage difference continuously exceeds the preset voltage value (such as > 3 V), it is determined as a short - circuit and a hard shutdown is triggered;

[0017] The voltage difference is monitored in real - time through a voltage detection circuit, and after the voltage difference matches successfully, it is switched to the main discharge circuit.

[0018] As a further solution of the present invention, the dynamic key mutual recognition includes the following steps:

[0019] The BMS generates a random number R1 and sends it to the charger;

[0020] The charger encrypts and generates a signature Sign = Hash(R1 + key) using the preset key, and the BMS verifies the legality of the signature;

[0021] After the verification passes, the BMS issues charging parameters (such as maximum current, voltage). When the verification fails, the BMS records the information of illegal devices and triggers the blacklist interception mechanism.

[0022] As a further solution of the present invention, the voltage - difference matching time of the pre - discharge is less than or equal to the pre - discharge control holding time (such as ≤ 20 ms).

[0023] As a further solution of the present invention, performing power reduction, soft shutdown or hard shutdown operations according to the fault level includes:

[0024] Discharge fault: When the temperature is greater than the preset temperature (such as > 65 °C) or the current is greater than the preset current (such as > 20 A), a power - reduction mode is triggered (providing SOP not exceeding 50% of the rated power); if the abnormality persists for more than the preset duration (such as 1 second), a hard shutdown is performed;

[0025] Charging fault: When the charger communication is interrupted for more than the preset time (such as 3 seconds) or the single - cell voltage exceeds the preset voltage (such as > 4.25 V), the charging is immediately terminated and the fault log is stored.

[0026] As a further solution of the present invention, the multi - level fault response further includes:

[0027] The fault level is divided according to the severity of the abnormality. The power reduction mode provides the SOP value available to the system within 50% of the rated value, and the hard shutdown directly cuts off the main circuit;

[0028] The fault classification accuracy rate is greater than the preset accuracy threshold (e.g., ≥95%), and the delay from abnormal detection to action execution is less than or equal to the preset duration (e.g., ≤30ms).

[0029] In a second aspect, the present invention also provides a charge and discharge safety control system for a small power battery management system, including the following components:

[0030] Pre-discharge module: It consists of a controllable MOSFET, a current-limiting resistor, and a voltage detection circuit, and is used to eliminate the pressure difference through small-current pre-discharge before the battery is connected to the load;

[0031] Hierarchical shutdown unit, which monitors overcurrent, short circuit, and temperature abnormalities during the discharge process in real time and triggers hierarchical shutdown operations;

[0032] Charge management module, including an encryption mutual recognition protocol unit and a charge fault management unit. The encryption mutual recognition protocol unit verifies the legality of the charger through dynamic key exchange and digital signature, and the charge fault management unit detects charge abnormalities and records fault codes;

[0033] Software control module, which is used to run the main state machine logic to realize charge and discharge mode switching, dynamic priority arbitration, and multi-level fault response.

[0034] As a further solution of the present invention, the working process of the pre-discharge module includes:

[0035] When the load is connected, pre-discharge is carried out with a small current below the set current value (e.g., 50mA) through the current-limiting resistor;

[0036] When it is detected that the pressure difference between the battery and the load terminal is less than or equal to the preset voltage (e.g., ≤3V), switch to the main discharge circuit;

[0037] If the pre-discharge times out or the pressure difference continuously exceeds the threshold, it is determined that the load is short-circuited and hard shutdown is performed.

[0038] As a further solution of the present invention, the encryption mutual recognition protocol unit supports AES-128 dynamic key exchange and charger legality verification.

[0039] As a further solution of the present invention, the working process of the encryption mutual recognition protocol unit includes:

[0040] The BMS generates a random number R1 and sends it to the charger;

[0041] The charger uses the preset key to perform hash encryption on R1 to generate a signature Sign and returns it;

[0042] After the BMS verifies the legality of the signature, it issues the charging parameters, otherwise it intercepts the charging request.

[0043] As a further solution of the present invention, the triggering of the hierarchical shutdown operation by the hierarchical shutdown unit includes three-level responses:

[0044] First-level response: The power reduction mode provides the SOP value available to the system within 50% of the rated value;

[0045] Second-level response: Soft shutdown, cutting off the discharge circuit after a 1-second delay;

[0046] Third-level response: Hard shutdown and lock the system, requiring manual reset.

[0047] As a further solution of the present invention, the software control module runs the main state machine logic, and the strategy for realizing dynamic priority arbitration is:

[0048] The priority of the fault shutdown instruction is higher than that of the charging request, and the priority of the charging request is higher than that of the discharge request.

[0049] Compared with the prior art, a charge and discharge safety control method and system for a small power battery management system proposed by the present invention have the following beneficial effects:

[0050] 1. The pre-discharge circuit is adopted to realize the gradient control of "small current pre-charging → voltage matching → main circuit conduction". The pre-discharge success rate is high, which can effectively eliminate the pressure difference between the battery and the load and avoid the generation of electric arcs; the contact life is increased from less than 10,000 times in the traditional solution to more than 100,000 times, greatly reducing the connector maintenance cost; when the discharge is abnormal, the hierarchical shutdown strategy (power reduction → soft shutdown → hard shutdown) reduces the hard shutdown trigger frequency and prolongs the life of key devices.

[0051] 2. Based on the dynamic key exchange protocol encrypted by AES-128, the charger and the BMS perform two-way identity authentication, support the blacklist mechanism to intercept illegal devices, and prevent unauthorized chargers from accessing; the interception rate of illegal chargers is 100%, eliminating the risks of overcharging and short-circuiting caused by charger mismatch; the dynamic key update mechanism effectively resists man-in-the-middle attacks, and the communication security reaches the financial level standard.

[0052] 3. Multilevel fault tolerance mechanism: hierarchical response according to the severity of the abnormality; dynamic priority arbitration strategy: "fault shutdown > charging > discharge" ensures the priority execution of safety instructions. Based on the main logic framework of the state machine, it supports seamless switching of charge and discharge modes, real-time fault log storage and remote upload functions, which are convenient for operation and maintenance diagnosis.

[0053] In summary, through the collaborative innovation of software and hardware, the present invention achieves the safety control objectives of "zero sparking, full compatibility, and fast response" for the BMS in small-power scenarios. Its technical indicators comprehensively exceed the existing technical level, and it has significant industrial application prospects.

[0054] These aspects or other aspects of the present application will be more clearly understood in the following description of the embodiments. It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the related art, the following briefly introduces the accompanying drawings required for the description of the exemplary embodiments or the related art. The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation to the present invention. In the accompanying drawings:

[0056] Figure 1 It is a flowchart of the charge and discharge safety control method for the small-power battery management system according to the embodiment of the present invention.

[0057] Figure 2 It is a flowchart of pre-discharging the battery and the load end in the charge and discharge safety control system of the small-power battery management system according to the embodiment of the present invention.

[0058] Figure 3 It is a flowchart of dynamic key mutual recognition in the charge and discharge safety control system of the small-power battery management system according to the embodiment of the present invention.

[0059] Figure 4 It is a structural block diagram of the charge and discharge safety control system of the small-power battery management system according to the embodiment of the present invention.

[0060] Figure 5 It is a schematic diagram of the main logic framework of the charge and discharge safety control system of the small-power battery management system according to the embodiment of the present invention.

[0061] Figure 6 It is a discharge logic flowchart of the charge and discharge safety control system of the small-power battery management system according to the embodiment of the present invention.

[0062] Figure 7 It is a handshake charging logic block diagram of the charge and discharge safety control system of the small-power battery management system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] Next, in combination with the accompanying drawings and the specific embodiments, the present application will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0064] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further elaborates on the embodiments of the present invention in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0065] It should be noted that all the expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities or non-identical parameters with the same name. It can be seen that "first" and "second" are only for the convenience of expression and should not be construed as a limitation on the embodiments of the present invention. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units inherently includes other steps or units.

[0066] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0067] The flowcharts shown in the accompanying drawings are only illustrative examples, and do not necessarily include all the content and operations / steps, nor do they necessarily need to be executed in the described order. For example, some operations / steps can also be decomposed, combined or partially merged, so the actual execution order may change according to the actual situation.

[0068] The following will elaborate on some embodiments of the present application in conjunction with the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0069] In view of solving the defects of existing small-power BMSs, such as the risk of discharge connection arcs, illegal charger access, and low fault management efficiency, the present invention proposes a charge and discharge safety control method and system for a small-power battery management system, which eliminates the pressure difference between the battery and the load end through a pre-discharge circuit, intercepts illegal chargers in combination with a dynamic key mutual recognition protocol, and adopts a multi-level fault response mechanism to achieve rapid protection.

[0070] See Figures 1 to 7 As shown, the embodiments of the present invention provide a charge and discharge safety control method for a small-power battery management system, including the following steps:

[0071] Step S10, Pre-discharge control: Through a pre-discharge circuit composed of a controllable MOSFET and a current-limiting resistor, pre-discharge the battery and the load terminal with a current of 50 mA, and reduce the voltage difference to within 3 V within 20 ms. If the pre-discharge times out or the voltage difference continuously > 3 V, it is determined as a short circuit and a hard shutdown is triggered.

[0072] In this step, refer to Figure 2 As shown, the pre-discharge of the battery and the load terminal includes the following steps:

[0073] Step S101, The pre-discharge current is 50 mA and the duration is 20 ms;

[0074] Step S102, If the pre-discharge times out or the voltage difference continuously > 3 V, it is determined as a short circuit and a hard shutdown is triggered;

[0075] Step S103, Real-time monitor the voltage difference through a voltage detection circuit, and switch to the main discharge circuit after the voltage difference matching is successful.

[0076] Step S20, Dynamic key mutual recognition: The BMS generates a random number R1 and sends it to the charger. The charger encrypts it using a preset key to generate a digital signature and returns it. After the BMS verifies the legality of the signature, it issues charging parameters.

[0077] In this step, refer to Figure 3 As shown, the dynamic key mutual recognition includes the following steps:

[0078] Step S201, The BMS generates a random number R1 and sends it to the charger;

[0079] Step S202, The charger encrypts it using a preset key to generate a signature Sign = Hash(R1 + key), and the BMS verifies the legality of the signature;

[0080] Step S203, After the verification passes, the BMS issues charging parameters (such as maximum current, voltage). When the verification fails, the BMS records the information of illegal devices and triggers the blacklist interception mechanism.

[0081] Among them, the voltage difference matching time for the pre-discharge ≤ 20 ms.

[0082] Step S30, Multi-level fault response: Perform power reduction, soft shutdown or hard shutdown operations according to the fault level.

[0083] In this step, performing power reduction, soft shutdown or hard shutdown operations according to the fault level includes:

[0084] Discharge fault: When the temperature > 65 °C or the current > 20 A, trigger the power reduction mode (provide SOP not exceeding 50% of the rated power); If the abnormality persists for more than 1 second, perform a hard shutdown;

[0085] Charging fault: When the charger communication is interrupted for more than 3 seconds or the single - cell voltage > 4.25V, charging is immediately terminated and the fault log is stored.

[0086] In this embodiment, the multi - level fault response further includes:

[0087] The fault level is divided according to the severity of the abnormality. The power - down mode provides the SOP value available to the system within 50% of the rated value, and the hard - off directly cuts off the main circuit.

[0088] The fault classification accuracy rate ≥ 95%, and the delay from abnormal detection to action execution ≤ 30ms.

[0089] The multi - level fault - tolerant mechanism adopted by the present invention responds in levels according to the severity of the abnormality; the dynamic priority arbitration strategy: "fault shutdown > charging > discharging" ensures that safety instructions are preferentially executed. The main logic framework based on the state machine supports seamless switching between charge and discharge modes, and has the functions of real - time fault log storage and remote upload, which is convenient for operation and maintenance diagnosis.

[0090] Step S40, dynamic priority arbitration: When there is a conflict between charge and discharge requests, the high - priority instruction is preferentially responded according to the safety level of "fault shutdown > charging > discharging".

[0091] The present invention uses a pre - discharge circuit to achieve gradient control of "small - current pre - charge → voltage matching → main - circuit conduction". The pre - discharge success rate is high, which can effectively eliminate the pressure difference between the battery and the load and avoid the generation of electric arcs; the contact life is increased from less than 10,000 times in the traditional scheme to more than 100,000 times, greatly reducing the maintenance cost of the connector; the hierarchical shutdown strategy (power - down → soft - off → hard - off) during discharge abnormality reduces the hard - off trigger frequency and extends the life of key devices.

[0092] See Figures 4 to 7 As shown, the embodiment of the present invention also provides a charge - discharge safety control system for a small - power battery management system, including the following components:

[0093] Pre - discharge module: Composed of a controllable MOSFET, a current - limiting resistor and a voltage detection circuit, it is used to eliminate the pressure difference through small - current pre - discharge before the battery is connected to the load.

[0094] Hierarchical shutdown unit, which monitors over - current, short - circuit and temperature abnormalities during the discharge process in real - time and triggers hierarchical shutdown operations.

[0095] Charging management module, including an encryption mutual - recognition protocol unit and a charging - fault management unit. The encryption mutual - recognition protocol unit verifies the legality of the charger through dynamic key exchange and digital signature, and the charging - fault management unit detects charging abnormalities and records fault codes.

[0096] The software control module is used to run the main state machine logic, implement charge and discharge mode switching, dynamic priority arbitration, and multi-level fault response.

[0097] In this embodiment, the working process of the pre-discharge module includes:

[0098] When the load is connected, pre-discharge is carried out with a small current of less than 50 mA through a current-limiting resistor;

[0099] When the voltage difference between the battery and the load terminal is detected to be ≤ 3 V, switch to the main discharge circuit;

[0100] If the pre-discharge times out or the voltage difference continuously exceeds the threshold, it is determined that the load is short-circuited and hard-shut off.

[0101] In this embodiment, the encryption mutual recognition protocol unit supports AES-128 dynamic key exchange and charger legality verification.

[0102] The present invention is based on the AES-128 encryption dynamic key exchange protocol, with two-way authentication between the charger and the BMS, supports the blacklist mechanism to intercept illegal devices, and prevents unauthorized chargers from accessing; the interception rate of illegal chargers is 100%, eliminating the risks of overcharging and short-circuit caused by charger mismatch; the dynamic key update mechanism effectively resists man-in-the-middle attacks, and the communication security reaches the financial level standard.

[0103] In this embodiment, the working process of the encryption mutual recognition protocol unit includes:

[0104] The BMS generates a random number R1 and sends it to the charger;

[0105] The charger uses the pre-set key to perform hash encryption on R1 to generate a signature Sign and returns it;

[0106] After the BMS verifies the legality of Sign, it issues charging parameters, otherwise it intercepts the charging request.

[0107] Among them, the hierarchical shutdown unit triggers the hierarchical shutdown operation including three-level responses:

[0108] First-level response: The power reduction mode provides the SOP value available to the system within 50% of the rated value;

[0109] Second-level response: Soft shutdown, cutting off the discharge circuit after a 1-second delay;

[0110] Third-level response: Hard shutdown and lock the system, requiring manual reset.

[0111] In this embodiment, the strategy for the software control module to run the main state machine logic and implement dynamic priority arbitration is:

[0112] The priority of the fault shutdown instruction is higher than that of the charging request, and the priority of the charging request is higher than that of the discharging request.

[0113] In summary, through the collaborative innovation of software and hardware, the present invention realizes the safety control objectives of "zero sparking, full compatibility, and fast response" of the BMS in small power scenarios. The technical indicators comprehensively exceed the existing technical level and have significant industrial application prospects.

[0114] The above are exemplary embodiments disclosed by the present invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments disclosed by the present invention as defined by the claims. The functions, steps, and / or actions of the method claims according to the disclosed embodiments herein do not need to be performed in any specific order. In addition, although the elements disclosed by the embodiments of the present invention can be described or claimed in an individual form, they can also be understood as plural unless explicitly limited to the singular.

[0115] It should be understood that, as used herein, unless the context clearly supports an exception, the singular form "a" is also intended to include the plural form. It should also be understood that the "and / or" used herein refers to any and all possible combinations of one or more of the associated listed items. The serial numbers of the disclosed embodiments of the present invention above are only for description and do not represent the advantages or disadvantages of the embodiments.

[0116] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the embodiments disclosed by the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of the present invention as above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. A charge and discharge safety control method for a small power battery management system, characterized in that, It includes the following steps: Pre-discharge control: A pre-discharge circuit composed of a controllable MOSFET and a current-limiting resistor is used to pre-discharge the battery and the load terminal with a pre-discharge current, reducing the voltage difference to within a preset value. If the pre-discharge times out or the voltage difference continuously exceeds the preset value, it is determined as a short circuit and hard shutdown is triggered; Dynamic key mutual recognition: The BMS generates a random number R1 and sends it to the charger. The charger encrypts and generates a digital signature using a preset key and returns it. After the BMS verifies the legality of the signature, charging parameters are issued; Multi-level fault response: Perform power reduction, soft shutdown, or hard shutdown operations according to the fault level; Dynamic priority arbitration: When there is a conflict between charge and discharge requests, high-priority instructions are preferentially responded to according to the safety level of "fault shutdown > charging > discharging".

2. The charging and discharging safety control method of the small power battery management system according to claim 1, characterized in that The pre-discharge of the battery and the load terminal includes the following steps: The pre-discharge current is a set value, and the duration is the pre-discharge control holding time; If the pre-discharge times out or the voltage difference continuously exceeds the preset voltage value, it is determined as a short circuit and hard shutdown is triggered; The voltage difference is monitored in real time through a voltage detection circuit, and after the voltage difference matches successfully, it switches to the main discharge circuit.

3. The charging and discharging safety control method of the small power battery management system according to claim 2, characterized in that, The dynamic key mutual recognition includes the following steps: The BMS generates a random number R1 and sends it to the charger; The charger encrypts and generates a signature Sign = Hash(R1 + key) using a preset key, and the BMS verifies the legality of the signature; After successful verification, the BMS issues charging parameters. When the verification fails, the BMS records illegal device information and triggers the blacklist interception mechanism.

4. The charging and discharging safety control method of the small power battery management system according to claim 3, characterized in that, The voltage difference matching time of the pre-discharge is less than or equal to the pre-discharge control holding time.

5. The charge and discharge safety control method of the small power battery management system according to claim 1, characterized in that, Performing power reduction, soft shutdown, or hard shutdown operations according to the fault level includes: Discharge fault: When the temperature is greater than the preset temperature or the current is greater than the preset current, a power reduction mode is triggered; if the abnormality persists for more than the preset duration, hard shutdown is performed; Charging fault: When the charger communication is interrupted for more than the preset time or the single-cell voltage exceeds the preset voltage, charging is immediately terminated and the fault log is stored.

6. The charging and discharging safety control method of the small power battery management system according to claim 5, characterized in that, The multi-level fault response further includes: The fault level is divided according to the severity of the abnormality. The power reduction mode provides the SOP value available to the system within 50% of the rated value, and the hard shutdown directly cuts off the main circuit; The fault classification accuracy rate is greater than the preset accuracy threshold, and the delay from anomaly detection to action execution is less than or equal to the preset duration.

7. A charge and discharge safety control system for a small power battery management system, characterized in that, A charge and discharge safety control method for a small power battery management system as described in any one of claims 1-6, and the system includes the following components: Pre-discharge module: Composed of a controllable MOSFET, a current-limiting resistor, and a voltage detection circuit, used to eliminate the voltage difference through small-current pre-discharge before the battery is connected to the load; Hierarchical shutdown unit, which monitors overcurrent, short circuit, and temperature anomalies during the discharge process in real time and triggers hierarchical shutdown operations; Charging management module, including an encryption mutual recognition protocol unit and a charging fault management unit. The encryption mutual recognition protocol unit verifies the legality of the charger through dynamic key exchange and digital signature. The charging fault management unit detects charging anomalies and records fault codes; Software control module, used to run the main state machine logic to realize charge and discharge mode switching, dynamic priority arbitration, and multi-level fault response.

8. The charge and discharge safety control system of the small power battery management system according to claim 7, characterized in that, The working process of the pre-discharge module includes: When the load is connected, pre-discharge is performed with a small current below the set current value through a current-limiting resistor; When it is detected that the voltage difference between the battery and the load terminal is less than or equal to the preset voltage, switch to the main discharge circuit; If the pre-discharge times out or the voltage difference continuously exceeds the threshold, it is determined that the load is short-circuited and hard-shut off.

9. The charge and discharge safety control system of the small power battery management system according to claim 8, characterized in that, The encryption mutual authentication protocol unit supports AES-128 dynamic key exchange and charger legality verification.

10. The charge and discharge safety control system of the small power battery management system according to claim 9, characterized in that, The working process of the encryption mutual authentication protocol unit includes: The BMS generates a random number R1 and sends it to the charger; The charger uses the preset key to perform hash encryption on R1 to generate a signature Sign and returns it; After the BMS verifies the legality of Sign, it issues charging parameters, otherwise intercepts the charging request.

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