A method for matching protection of vehicle battery system overload fuse

Abstract

The application provides a kind of vehicle battery system overload fuse matching protection method, belongs to the field of automobile safety technology.Firstly, the corresponding tolerance curve of single battery, battery module and related parts is determined;Then determine the rated current interval of the fuse;Then obtain the tolerance curve of different models of fuses under the rated current interval, determine the fuse model that can effectively protect the battery system;Finally, the temperature rise test of the fuse is carried out, the battery charge and discharge characteristics are determined, and whether the obtained battery charge and discharge characteristics meet the vehicle power performance requirements is judged;When the requirements are met, the fuse of this type is used as the fuse for protecting the battery system overload;When the requirements are not met, the fuse model is matched again until the vehicle power performance requirements are met.The application realizes the accurate matching of the fuse with the vehicle battery, battery system and parts, improves the safety performance of the vehicle, and solves the problem of protection blind area in the existing fuse selection method.

Description

Technical Field

[0001] This invention relates to a method for matching and protecting overload fuses in a vehicle battery system, belonging to the field of automotive safety technology. Background Technology

[0002] With the continuous development of new energy technologies, the safety of battery systems has become a focus of attention in the industry. Battery system safety protection relies not only on improving the safety performance of individual cells but also on enhancing the safety performance at the battery system level. Currently, vehicle short-circuit protection mainly uses fuses. The selection of fuses is primarily based on theoretical calculations of the parameters of the protected battery system, resulting in low compatibility with the system. If the short-circuit protection device is too large, it cannot effectively protect against small current overloads; if it is too small, there is a risk of false tripping during long-term continuous operation and impact resistance, raising reliability issues, especially regarding insufficient tolerance to short-term impacts of over 1000 amperes during vehicle start-up. There are also methods for correcting fuse and wire matching based on the heating and heat transfer mechanisms of fuses and wires. For example, in patent application CN201310033051.X entitled "Precise Matching Method for Automobile Fuses and Connecting Wires," a mathematical model of the rated operating current of the connecting wires is established, followed by a basic database of vehicle voltage wires and fuses. Finally, based on the basic database of low-voltage wires and fuses, the theoretical matching results of the fuses and their connecting wires in the mathematical model of the rated operating current of the connecting wires are corrected to obtain the final precise matching relationship between the fuses and connecting wires. Although the above methods can achieve short-circuit protection for electric vehicles to a certain extent, they mainly rely on theoretical calculations or matching protection with connecting wires alone. There are still blind spots in the protection of the entire vehicle, and no system-level matching verification is performed, resulting in limited matching accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide a method for matching and protecting overload fuses in a vehicle battery system, in order to solve the problem that the matching between fuses and battery systems and related components in the prior art is low, making it difficult to achieve effective protection for the whole vehicle.

[0004] This invention proposes a method for overload fuse matching protection in a vehicle battery system, the method comprising the following steps:

[0005] 1) Conduct endurance time tests on individual cells, battery modules, and related components of the battery system to obtain the corresponding endurance curves for individual cells, battery modules, and related components;

[0006] 2) Determine the continuous operating current of the battery system load and the derating factor of the fuse, and determine the rated current range of the fuse based on the determined continuous operating current and derating factor;

[0007] 3) Based on the rated current range of the fuse, obtain the withstand curves of different fuse models within the rated current range; based on the withstand curves of individual cells, battery modules and related components, determine the fuse models that can effectively protect individual cells, battery modules and related components.

[0008] 4) Perform temperature rise tests on the selected fuse models to determine the battery charge and discharge characteristics and judge whether the obtained battery charge and discharge characteristics meet the vehicle power performance requirements; when the battery charge and discharge characteristics meet the vehicle power performance requirements, use the fuse model as the overload protection fuse for the battery system; when the battery charge and discharge characteristics do not meet the vehicle power performance requirements, rematch the fuse model until the battery charge and discharge performance meets the vehicle power performance requirements.

[0009] This invention also proposes a method for overload fuse matching protection of a vehicle battery system, the method comprising the following steps:

[0010] 1) Conduct endurance time tests on individual cells, battery modules, and related components of the battery system to obtain the corresponding endurance curves for individual cells, battery modules, and related components;

[0011] 2) Determine the continuous operating current of the battery system load and the derating factor of the fuse, and determine the rated current range of the fuse based on the determined continuous operating current and derating factor;

[0012] 3) Based on the rated current range of the fuse, obtain the withstand curves of different fuse models within the rated current range; based on the withstand curves of individual cells, battery modules and related components, determine the fuse models that can effectively protect individual cells, battery modules and related components.

[0013] 4) Perform temperature rise tests on the selected fuse models to determine the battery charge-discharge characteristics and assess whether the obtained battery charge-discharge characteristics meet the vehicle's power performance requirements. If the battery charge-discharge characteristics meet the vehicle's power performance requirements, use this fuse model for battery system overload protection. If the battery charge-discharge characteristics do not meet the vehicle's power performance requirements, adjust the battery MAP table. Based on the adjusted battery MAP table, determine whether it meets the temperature rise test requirements. If it meets the temperature rise test requirements, determine whether the battery charge-discharge characteristics obtained after adjusting the battery MAP table meet the vehicle's power performance requirements. If it meets the vehicle's power performance requirements, use this fuse model for battery system overload protection. If it does not meet the vehicle's power performance requirements, continue adjusting the battery MAP table within the set number of adjustments until the battery charge-discharge characteristics obtained after adjusting the battery MAP table meet the vehicle's power performance requirements. If, after reaching the set number of adjustments, the battery charge-discharge characteristics obtained after adjusting the battery MAP table still do not meet the vehicle's power performance requirements, re-match the fuse model until the vehicle's power performance requirements are met.

[0014] This invention selects fuse models capable of effectively protecting the battery system based on the withstand curves of individual cells, battery modules, and related components, as well as the fuse withstand curves within the rated current range. This allows the selected fuses to provide overload protection for the entire vehicle. Temperature rise tests are then conducted on the selected fuses to determine the battery's charge and discharge characteristics and whether they meet the vehicle's power performance requirements, ensuring precise matching between the vehicle's battery system and the fuse protection. This invention matches fuses capable of providing overload protection for the entire vehicle, improving the compatibility between fuses and battery systems in existing fuse selection methods. Furthermore, temperature rise tests are performed on the matched fuses to ensure they provide effective protection while also meeting the vehicle's power performance requirements. This achieves precise matching between the fuse and the vehicle battery, battery system, and components, improving overall vehicle safety and resolving the protection blind spots inherent in relying solely on theoretical calculations or matching protection only with wires.

[0015] Furthermore, to avoid over-protection of the battery system by the fuse, when the vehicle's power performance requirements are met, a matching retest of the fuse and battery system is performed to find the minimum current value corresponding to the fuse blowing before the battery system fails. If the minimum current value is less than or equal to the set effective protection threshold and greater than or equal to the set over-protection threshold, then the fuse of that model is used as the fuse for battery system overload protection. If the minimum current value is greater than the set effective protection threshold or less than the set over-protection threshold, then the battery MAP table data is adjusted or a new fuse model is selected.

[0016] Furthermore, in order to improve the efficiency of the matching retest of the fuse and battery system, the matching retest method of the fuse and battery system is the screening point method. Based on the determined withstand curve of the fuse and the withstand time of the battery under different currents, an intermediate current value is first selected for testing. When the test result at this current shows that the fuse achieves effective protection, the current value is reduced and the test continues. When the test result at this current value shows that the fuse cannot achieve effective protection, the current value is increased and the test continues until the minimum current value at which the fuse achieves effective protection is found.

[0017] Furthermore, the relevant components in step 1) include connecting wires between the cells, connecting wires of the battery system, contactors, and high-voltage cables.

[0018] Furthermore, in order to meet the temperature rise requirements of the fuse, the temperature rise test process in step 4) is as follows: test the temperature rise of the fuse according to the charging and discharging current in the existing battery MAP table, and adjust the battery MAP table data according to the test results until the temperature rise requirements of the fuse are met.

[0019] Furthermore, the effective protection of the battery means that under different currents, the battery's withstand time is greater than the fuse's melting time under that current, or the battery's withstand time is less than the fuse's melting time under that current, but the battery will not fail when it is discharged from a fully charged state to the lowest voltage state before the fuse melts under that current.

[0020] Furthermore, in order to quickly determine the continuous operating current of the fuse load, the continuous operating current in step 2) is determined based on the continuous operating current of the vehicle drive system, the short-time inrush current of the drive system load switch, and the overload current and duration when an overload condition exists.

[0021] Furthermore, in order to quickly determine the derating factor of the fuse, the derating factor in step 2) is determined based on the fuse's operating temperature, the heating of the connector, the operating altitude, and the service life.

[0022] Furthermore, in order to obtain a reasonable test point current and reduce unnecessary tests to improve test efficiency, the test point current in step 1) of the endurance time test is selected based on the rate characteristics of the battery, and the upper limit of the selected test point current is the battery's limiting short-circuit current. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the vehicle system overload fuse matching protection method in Embodiment 1 of the present invention.

[0024] Figure 2 This is a flowchart illustrating the vehicle system overload fuse matching protection method in Embodiment 2 of the present invention.

[0025] Figure 3 This is a tolerance curve diagram of the single battery cell, battery module, fuse and related components of the present invention;

[0026] Figure 4 This is a schematic diagram illustrating the method of determining the minimum current value using the screening point method of this invention. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0028] Example 1

[0029] This invention proposes a method for overload fuse matching protection in vehicle battery systems, the specific process of which is as follows: Figure 1 As shown, the process begins with endurance time tests on individual cells, battery modules, and related components of the battery system to obtain their respective endurance curves. Next, the continuous operating current of the battery system load and the derating factor of the fuses are determined. Based on these factors, the rated current range of the fuses is then determined. Next, the endurance curves of different fuse models within the rated current range are obtained to identify the fuse models that effectively protect the individual cells, battery modules, and related components. Finally, temperature rise tests are performed on the selected fuse models to determine the battery charge-discharge characteristics and assess whether these characteristics meet the vehicle's power performance requirements. When the battery charge-discharge characteristics meet the vehicle's power performance requirements, this fuse model is used for overload protection of the battery system. When the battery charge-discharge characteristics do not meet the vehicle's power performance requirements, the fuse model is re-matched until the battery charge-discharge performance meets the vehicle's power performance requirements. This invention improves the matching between fuses and battery systems in existing fuse selection methods. At the same time, it conducts temperature rise tests on the matched fuses to ensure that the fuses can meet the power performance requirements of the vehicle while providing effective protection. This achieves precise matching between the fuses and the vehicle battery, battery system and components, improves the safety performance of the vehicle, and solves the protection blind spot problem that exists when relying solely on theoretical calculations or matching protection only with wires.

[0030] Step 1. Generate battery system tolerance curves

[0031] This invention first conducts endurance time tests on individual cells, battery modules, and related components of the battery system. The test results are then used to perform curve fitting to generate endurance curves for each individual cell, battery module, and related component. Specifically, the endurance time of each individual cell, battery module, and related component is fitted based on the characteristic time determined by the tests to generate the corresponding endurance curve. Related components include connecting wires between individual cells, connecting wires of the battery system, contactors, and high-voltage cables.

[0032] In the endurance time test, the test point current is selected based on the battery's rate capability. For example, test points are selected for three segments: 500A-1500A, 1500A-3000A, and above 3000A. For 500A-1000A, points can be selected every 200A; for 1500A-3000A, every 500A; and for above 3000A, every 2000A. To reduce unnecessary testing and improve efficiency, the upper limit of the selected test point current is the battery's maximum short-circuit current. Furthermore, for low-temperature and low-SOC states, supplementary tests are required, and the selection of the test point current can be appropriately relaxed in these cases. Alternatively, the selection of the test point current can be determined based on the actual condition of the battery. Battery endurance time refers to the maximum time a battery can withstand at any given current. Exceeding this time will result in battery failures such as leakage, electrode melting, internal thermal runaway, and safety valve opening.

[0033] In this embodiment, endurance time tests are performed on the individual cells, battery modules, and related components of the battery system. Multiple current test points are selected to test the endurance time of the individual cells, battery modules, and related components under different current values. Curve fitting is performed on the generated feature points, and the results are as follows. Figure 3 As shown, it can be seen that the withstand time of different components decreases as the current value increases.

[0034] Step 2. Determine the rated current range of the fuse.

[0035] To find the fuse with the best match for the vehicle battery system among various fuse models, the continuous operating current of the battery system load and the derating factor of the fuse are first determined, and then the rated current range of the fuse is determined based on the determined continuous operating current and derating factor.

[0036] When determining the rated current range of a fuse, the impact of surge current during load switching, the assessment of overload current values ​​and durations for loads under overload conditions, and the influence of factors such as whether the load current is continuous or pulsed and the duration of operation should be considered. The rated current of the fuse should not be less than the maximum continuous operating current value in the high-voltage circuit where the fuse is located. The specific calculation process is as follows:

[0037] a) Determine the continuous operating current I of the battery system load. RMS It is determined by the continuous operating current of the vehicle drive system, the short-term impact current of the drive system load, and the overload current and duration under overload conditions; it can be obtained by dividing the rated power by the nominal voltage.

[0038] b) Determine the technical requirements for the fuse's operating temperature, the heating of connecting components, operating altitude, and service life, and obtain various parameters including thermal connection (K). e ), air-cooled (K) v ), ambient temperature (K) t ), frequency (K f Altitude coefficient (K) a The current periodicity parameter (A2) and load start-stop cycle (A3) are obtained, and the derating factor is determined by multiplying these parameters. Furthermore, for applications involving high altitudes, high temperatures, and frequent current surges in the operating circuit, the derating factor needs to be increased.

[0039] c) Determine the rated current of the fuse

[0040]

[0041] Based on the calculated rated current range of the fuse, the rated current selection of the fuse needs to be checked for devices with capacitors, inductors, and transformers in the circuit, or for equipment such as motor loads that are subject to starting current surges and overload conditions, to ensure that it can withstand such surge currents and operate normally throughout its entire lifespan.

[0042] Step 3. Match the fuse model

[0043] Based on the rated current range of the fuse determined in step 2, fuse models are screened, selecting those with rated currents within the rated current range. The withstand curves of each screened fuse model are obtained. Based on the withstand curves of individual batteries, battery modules, and related components, the fuse model that effectively protects these components is determined. Specifically, when the fuse's withstand curve is entirely below the withstand curves of individual batteries, battery modules, and related components (i.e., the fuse's withstand time at the same current is less than that of individual batteries, battery modules, and related components), it is determined that the fuse can effectively protect these components. However, the selected fuse curve should not be too low to avoid overprotection or a significant decrease in the overall vehicle performance of the battery system. Therefore, a fuse with a withstand curve that is entirely below other withstand curves, yet not too far from them, needs to be selected.

[0044] Effective battery protection means that, under different currents, the battery's withstand time is greater than the fuse's melting time at that current, or the battery's withstand time is less than the fuse's melting time at that current, but the battery does not experience leakage, tab melting, internal thermal runaway, or safety valve opening when discharged from a fully charged state to its lowest voltage state before the fuse blows at that current. If the battery's withstand time is less than the fuse's melting time at that current, and the battery experiences leakage, tab melting, internal thermal runaway, or safety valve opening before the fuse blows at that current, then the protection fails.

[0045] In this embodiment, according to Figure 3 The tolerance curves of individual cells, battery modules, and related components in the battery system are used to identify the tolerance curves of fuses that can effectively protect the battery system. Figure 2 The withstand curve of the high-voltage DC fuse in the figure is shown. Figure 3 It can be seen that the withstand curve of the fuse is generally lower than that of other withstand curves, except when the current value is between 700A and 800A, the withstand curve of the fuse is above the withstand curves of the connecting wires between cells, the connecting wires inside the box, and the contactor. However, this does not mean that the fuse cannot effectively protect the battery system. Because when the current value is low, if the battery is discharged from a fully charged state to the lowest voltage state without failure, and the selected fuse also blows at this current, then over-protection will occur, causing a decline in the performance of the battery system and the whole vehicle.

[0046] Step 4. Fuse Temperature Rise Test

[0047] Based on the selected fuse model, a temperature rise test is performed on the fuse to determine the battery charge and discharge characteristics, and to determine whether the obtained battery charge and discharge characteristics meet the vehicle's power performance requirements. When the battery charge and discharge characteristics meet the vehicle's power performance requirements, the fuse model is used as the overload protection fuse for the battery system. When the battery charge and discharge characteristics do not meet the vehicle's power performance requirements, the fuse model is rematched until the battery charge and discharge performance meets the vehicle's power performance requirements.

[0048] The temperature rise test process for the fuse is as follows: The temperature rise of the fuse is tested based on the charging and discharging current in the existing battery MAP (Magnetic Assurance Table). The battery MAP data is adjusted according to the test results. If the fuse temperature rise exceeds the test standard, the charging and discharging current in the MAP is reduced by 10%, and the test is repeated until the temperature rise requirement of the fuse is met. In actual testing, the charging and discharging current derating factor in the MAP can be determined based on experience for retesting. Alternatively, the operating current of the actual vehicle can be collected, and the temperature rise of the fuse can be tested according to the operating current. As another implementation method, if the temperature rise test does not meet the temperature rise requirement, the fuse can be directly rematched.

[0049] Step 5. Perform a matching retest on the battery system and fuses.

[0050] After the temperature rise test, the model of the fuse capable of effectively protecting the battery system has been determined. To avoid over-protection or failure protection of the battery system by the fuse, a matching retest of the battery system and the fuse is performed. A screening point method is used to determine the minimum current value corresponding to the fuse blowing before the battery system fails. This value is compared with the set effective protection threshold and the set over-protection threshold, where the over-protection threshold is less than the effective protection threshold. When the minimum current value is less than or equal to the effective protection threshold and greater than the over-protection threshold, it indicates that the fuse can achieve overload protection of the battery system without causing over-protection. When the minimum current value is greater than the effective protection threshold or greater than the over-protection threshold, the battery MAP data is adjusted or a new fuse model is selected. As another implementation method, the threshold settings can be determined according to the specific actual situation of different vehicle battery systems, based on the principle of effectively protecting the battery without causing over-protection. For example, if the found minimum current value is 800A, the effective protection threshold is set to 1000A, and the over-protection threshold is set to 600A, it indicates that the fuse can achieve overload protection of the battery system without causing over-protection. However, if the minimum current value is 500A, it is necessary to adjust the MAP data or select a different fuse model. Although this type of fuse can effectively protect the battery system, the battery system will not fail at a current of 500A. If this type of fuse is still used, the high-voltage circuit of the battery system will be interrupted without any risk, affecting the normal operation of the system. Such overprotection is meaningless.

[0051] The specific process for determining the minimum current value using the screening point method is as follows: Based on the established withstand curve of the fuse and the battery's withstand time at different currents, an intermediate current value is first selected for testing. If the test results at this current value show that the fuse can provide effective protection, the current value is reduced and testing continues. If the test results at this current value show that the fuse cannot provide effective protection, the current value is increased and testing continues until the minimum current value at which the fuse provides effective protection is found. For example, ... Figure 4 As shown, the selected intermediate current value is 1400A. If the test result of 1400A current shows that the fuse blows before the battery system fails, then continue to select 1000A for testing. If the test result of 1000A current shows that the fuse blows before the battery fails, then continue to select 800A for testing. If the test result of 1400A current shows that the fuse blows after the battery fails, then continue to select 2000A for testing, and so on, until the minimum current value at which the fuse can effectively protect the battery system is found.

[0052] Example 2

[0053] This invention also proposes a method for overload fuse matching protection of a vehicle battery system, the specific process of which is as follows: Figure 2 As shown, firstly, endurance time tests are conducted on individual cells, battery modules, and related components of the battery system to obtain the corresponding endurance curves. Next, the rated current range of the fuse is determined. Then, the endurance curves of different fuse models within the rated current range are obtained to determine the fuse model that effectively protects the individual cells, battery modules, and related components. Finally, temperature rise tests are conducted on the selected fuse models to determine the battery charge-discharge characteristics and whether these characteristics meet the vehicle's power performance requirements. When the battery charge-discharge characteristics meet the vehicle's power performance requirements, this fuse model is used as the overload protection fuse for the battery system. When the battery charge-discharge characteristics do not meet the vehicle's power performance requirements, the battery MAP table is adjusted, and the model of the overload protection fuse for the battery system is determined using the adjusted battery MAP table.

[0054] This method is consistent with the specific implementation of the vehicle battery system overload fuse matching protection method in Example 1. The difference is that when the battery charging and discharging characteristics do not meet the vehicle's power performance requirements, this method adjusts the battery MAP (Magnetic Mapping) table. Based on the adjusted battery MAP table, it is determined whether the temperature rise test requirements are met. If the temperature rise test requirements are met, it is determined whether the battery charging and discharging characteristics obtained after adjusting the battery MAP table meet the vehicle's power performance requirements. If the vehicle's power performance requirements are met, the fuse of that model is used as the fuse for battery system overload protection. If the vehicle's power performance requirements are not met, the battery MAP table is adjusted again within a set number of adjustments until the battery charging and discharging characteristics obtained after adjusting the battery MAP table meet the vehicle's power performance requirements. If, after reaching the set number of adjustments, the battery charging and discharging characteristics obtained after adjusting the battery MAP table still do not meet the vehicle's power performance requirements, the fuse model is rematched until the vehicle's power performance requirements are met.

[0055] This invention uses the two methods described above to select fuses that can effectively protect the vehicle battery system, achieving precise matching between the fuses and the vehicle battery, battery system, and components, thereby improving the overall vehicle safety performance.

Claims

1. A method for overload fuse matching protection in a vehicle battery system, characterized in that, The method includes the following steps: 1) Conduct endurance time tests on individual cells, battery modules, and related components of the battery system to obtain the corresponding endurance curves for individual cells, battery modules, and related components; 2) Determine the continuous operating current of the battery system load and the derating factor of the fuse, and determine the rated current range of the fuse based on the determined continuous operating current and derating factor; 3) Based on the rated current range of the fuse, obtain the withstand curves of different fuse models within the rated current range; based on the withstand curves of individual cells, battery modules and related components, determine the fuse models that can effectively protect individual cells, battery modules and related components; 4) Perform temperature rise tests on the selected fuse models to determine the battery charge-discharge characteristics and assess whether the obtained battery charge-discharge characteristics meet the vehicle's power performance requirements. When the battery charge-discharge characteristics meet the vehicle's power performance requirements, retest the matching of the fuse and the battery system to find the minimum current value corresponding to the fuse melting before the battery system fails. If this minimum current value is less than or equal to the set effective protection threshold and greater than or equal to the set over-protection threshold, then use this fuse model as the overload protection fuse for the battery system. If this minimum current value is greater than the set effective protection threshold or less than the set over-protection threshold, then adjust the battery MAP table data or reselect the fuse model. When the battery charge-discharge characteristics do not meet the vehicle's power performance requirements, rematch the fuse model until the battery charge-discharge performance meets the vehicle's power performance requirements.

2. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, In step 1), when conducting endurance time tests on individual cells and battery modules of the battery system, the endurance time refers to the maximum time that an individual cell or battery module can withstand under any current.

3. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, The matching retest method for the fuse and battery system is the screening point method. Based on the determined withstand curve of the fuse and the withstand time of the battery system under different currents, an intermediate current value is first selected for testing. When the test result at this current shows that the fuse achieves effective protection, the current value is reduced and the test continues. When the test result at this current value shows that the fuse cannot achieve effective protection, the current value is increased and the test continues until the minimum current value at which the fuse achieves effective protection is found.

4. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, The relevant components in step 1) include the connecting wires between the cells, the connecting wires of the battery system, the contactor, and the high-voltage cable.

5. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, The temperature rise test process in step 4) is as follows: test the temperature rise of the fuse according to the charging and discharging current in the existing battery MAP table, and adjust the battery MAP table data according to the test results until the temperature rise of the fuse meets the requirements.

6. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, Effective protection of the battery means that, under different currents, the battery's withstand time is greater than the fuse's melting time under that current, or the battery's withstand time is less than the fuse's melting time under that current, but the battery will not fail when it is discharged from a fully charged state to the lowest voltage state before the fuse melts under that current.

7. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, The continuous operating current in step 2) is determined based on the continuous operating current of the vehicle drive system, the short-term impact current of the drive system load, and the overload current and duration when overload conditions exist.

8. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, The derating factor in step 2) is determined based on the fuse's operating temperature, the heating of the connector, the operating altitude, and the service life.

9. The overload fuse matching protection method for a vehicle battery system according to claim 1, characterized in that, In step 1), the test point current in the endurance time test is selected based on the rate characteristics of the battery, and the upper limit of the selected test point current is the battery's ultimate short-circuit current.

10. A method for matching and protecting a vehicle battery system overload fuse, characterized in that, The method includes the following steps: 1) Conduct endurance time tests on individual cells, battery modules, and related components of the battery system to obtain the corresponding endurance curves for individual cells, battery modules, and related components; 2) Determine the continuous operating current of the battery system load and the derating factor of the fuse, and determine the rated current range of the fuse based on the determined continuous operating current and derating factor; 3) Based on the rated current range of the fuse, obtain the withstand curves of different fuse models within the rated current range; based on the withstand curves of individual cells, battery modules and related components, determine the fuse models that can effectively protect individual cells, battery modules and related components; 4) Perform temperature rise tests on the selected fuse models to determine the battery charge-discharge characteristics and assess whether the obtained battery charge-discharge characteristics meet the vehicle's power performance requirements. If the battery charge-discharge characteristics meet the vehicle's power performance requirements, use this fuse model for battery system overload protection. If the battery charge-discharge characteristics do not meet the vehicle's power performance requirements, adjust the battery MAP table. Based on the adjusted battery MAP table, determine whether it meets the temperature rise test requirements. If it meets the temperature rise test requirements, determine whether the battery charge-discharge characteristics obtained after adjusting the battery MAP table meet the vehicle's power performance requirements. If it meets the vehicle's power performance requirements, use this fuse model for battery system overload protection. If it does not meet the vehicle's power performance requirements, continue adjusting the battery MAP table within the set number of adjustments until the battery charge-discharge characteristics obtained after adjusting the battery MAP table meet the vehicle's power performance requirements. If, after reaching the set number of adjustments, the battery charge-discharge characteristics obtained after adjusting the battery MAP table still do not meet the vehicle's power performance requirements, re-match the fuse model until the vehicle's power performance requirements are met.

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