Design method and system for relay and fuse in power battery system

Abstract

The invention discloses a design method and system for a relay and a fuse in a power battery system, and the method comprises the steps: firstly, obtaining a current parameter and a correction parameter of the power battery system; secondly, selecting a relay model based on the obtained current parameter, and selecting a fuse model based on the obtained current parameter and the correction parameter; then, matching and fitting are conducted on the selected relay and the fuse, and if matching and fitting of the relay and the fuse succeed, the number of times of service life of the fuse is estimated under the peak current time; and finally, based on the estimated life times of the fuse, determining whether the fuse meets design requirements or not. Through the matching design of the relay and the fuse in the power battery system and the estimation of the service life of the fuse, the reasonability of the design can be ensured, even the safety problem caused by the mismatching of the design and the dissatisfaction of the service life can be avoided, and the reliability and the safety of the power battery system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a design method and system for relays and fuses in a power battery system. Background Art

[0002] As a key component of electric vehicles, the existing power battery system has electrical properties such as power and energy that play a vital role in the power and economy of electric vehicles. Among them, the matching design of the relay and fuse of the power battery system and the fuse life directly affect the performance, life and other safety of the power battery system. In the early stage of the scheme design, the matching design of the relay and fuse of the power battery system and the estimation of the fuse life can not only ensure the rationality of the design, but also avoid safety problems caused by design mismatch and unsatisfactory life.

[0003] Recently, when designing power battery system solutions, there is a situation that only the selection of relays and fuses is verified, and the matching design of power battery system relays and fuses and the fuse life are not estimated. Instead, the safety and reliability test of the whole vehicle is carried out after the power battery system samples are completed, and then the solution is optimized and rectified according to the actual test results, which leads to the problem of too long cycle; in addition, there is also the situation that the selection of relays and fuses is verified based on the personal experience of engineers, and the rationality of relay and fuse design is roughly verified, and the life estimation results are inaccurate. Therefore, in order to design and develop power battery systems more efficiently, it is particularly important to find an accurate, simple and fast design method for power battery system relays and fuses. Summary of the invention

[0004] In view of the above problems, the present invention provides a method and system for designing relays and fuses in a power battery system. The method and system make the design of relays and fuses more accurate, quick and reliable.

[0005] The object of the present invention is to provide a design method for relays and fuses in a power battery system, comprising:

[0006] Obtain current parameters and correction parameters of the power battery system;

[0007] Selecting a relay model based on the acquired current parameter, and selecting a fuse model based on the acquired current parameter and the correction parameter;

[0008] The selected relay and fuse are matched and fitted. If the relay and fuse are matched and fitted successfully, the number of fuse life times is estimated under the peak current time;

[0009] Based on the estimated fuse life times, determine whether the fuse meets the design requirements.

[0010] Furthermore, obtaining the current parameters of the power battery system includes:

[0011] Based on the MAP table of the power battery system, obtain one or more of the following system parameters:

[0012] The total number of cells in series and parallel in the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection parts, the rated power of the power battery system, the open-circuit voltage of the cells at the rated power, the peak power of the power battery system, and the open-circuit voltage of the cells at the peak power;

[0013] Based on the obtained one or more system parameters, the rated current and peak current of the power battery system are calculated.

[0014] Further, based on the acquired one or more system parameters, the rated current and the peak current of the power battery system are calculated, including:

[0015] Determine the voltage U of the power battery system and the total DC internal resistance R of the power battery system 总 And the relationship between the output power P of the power battery system:

[0016] P=UI-I 2 R 总 (1)

[0017] Where P is the output power of the power battery system, U is the voltage of the power battery system, I is the current value of the power battery system, R 总 is the total DC internal resistance of the power battery system, where:

[0018] U=U cell ×n s (2)

[0019] Where U cell is the open circuit voltage of the cell, n s The total number of battery cells in the power battery system;

[0020]

[0021] In the formula, R 电芯总 is the total internal resistance of the cell, R 铝铜排 is the total internal resistance of the copper and aluminum bars of the connector, R 电器件 is the total internal resistance of all electrical components and R 接触电阻 is the total contact resistance of all bolted connection points, R cell is the internal resistance of the cell, n pis the total number of cells in the power battery system, ρ is the resistivity of the copper-aluminum bar of the connecting piece, L is the length of the copper-aluminum bar of the connecting piece, and S is the cross-sectional area of ​​the copper-aluminum bar of the connecting piece.

[0022] Further, based on the acquired one or more system parameters, calculating the rated current of the power battery system also includes:

[0023] Substitute the open circuit voltage of the battery cell at rated power and the total number of battery cells in the power battery system into formula (2) to calculate the voltage of the power battery system at rated power;

[0024] Substitute the total number of series and parallel cells of the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection into formula (3) to calculate R 总 ;

[0025] The rated power of the power battery system, the voltage of the power battery system at the calculated rated power, and R 总 Substitute into formula (1) to calculate the rated current of the power battery system.

[0026] Further, based on the acquired one or more system parameters, calculating the peak current of the power battery system also includes:

[0027] Substitute the open circuit voltage of the battery cell at peak power and the total number of battery cells in the power battery system into formula (2) to calculate the voltage of the power battery system at peak power;

[0028] Substitute the total number of series and parallel cells of the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection into formula (3) to calculate R 总 ;

[0029] The peak power of the power battery system, the calculated power battery system voltage at the peak power, and R 总 Substitute into formula (1) to calculate the peak current of the power battery system.

[0030] Furthermore, obtaining the power battery system correction parameters includes obtaining the following correction coefficients:

[0031] Correction factor K for ambient temperature t , Thermal connection correction factor K e , Air cooling correction factor K v , frequency correction factor K f , fuse system number K b .

[0032] Further, selecting a relay model based on the acquired current parameters of the power battery system includes:

[0033] Select a relay whose rated current and peak current agree with the calculated rated current and peak current.

[0034] Further, selecting a fuse model based on the acquired current parameters and correction parameters includes,

[0035] Determine the relationship between the rated current of the power battery system and the rated current and correction parameters of the fuse:

[0036] I b =I n ×K t ×K e ×K v ×K f ×K b (4)

[0037] Among them, I b is the rated current of the power battery system, I n is the rated current of the fuse, and the correction parameters include K t is the correction factor for ambient temperature, K e is the thermal connection correction factor, K v is the air cooling correction factor, K f is the frequency correction factor, K b is the fuse system number;

[0038] Substitute the various correction factors and rated currents obtained into formula (4) to calculate the rated current I of the fuse n ;

[0039] Select I n A fuse with a current rating greater than or equal to the preset current rating.

[0040] Furthermore, matching and fitting the selected relay and fuse includes:

[0041] Obtain time and current parameter curves of the selected relay and fuse respectively;

[0042] Based on the maximum cut-off current of the relay selected by the power battery system and the time and current parameter curves of the selected relay and fuse, it is determined whether the selected fuse and relay match each other.

[0043] If, after the maximum cut-off current of the selected relay, the time and current parameter curves of the relay and the fuse show that the fuse withstand time is less than the relay withstand time, the selected fuse and relay match fitting is successful;

[0044] Otherwise, the selected fuse and relay fail to match each other, and the fuse must be reselected.

[0045] Furthermore, before matching and fitting the selected relay and fuse, the method further includes collecting time and current parameters of relays of different specifications and time and current parameters of fuses of different specifications.

[0046] Furthermore, if the relay and the fuse are matched and fitted successfully, the estimated fuse life times under the peak current time include,

[0047] Obtain the ratio of the fuse's impulse current resistance under peak current and peak current time;

[0048] Based on the obtained ratio, the fuse life times are obtained from the fuse life times library.

[0049] Further, based on the estimated number of fuse lifespans, determining whether the fuse meets the design requirements includes:

[0050] If the estimated number of fuse life cycles is greater than the preset number, the fuse meets the design requirements;

[0051] Otherwise, the fuse does not meet the design requirements, and the relay and fuse should be reselected.

[0052] Another object of the present invention is to provide a design system for relays and fuses in a power battery system, comprising:

[0053] An acquisition module, used to acquire current parameters and correction parameters of a power battery system;

[0054] A selection module, for selecting a relay model based on the acquired current parameters, and for selecting a fuse model based on the acquired current parameters and correction parameters;

[0055] A matching module is used to match the selected relay and fuse;

[0056] An estimation module, used for estimating the number of fuse life times under the peak current time if the relay and the fuse are matched and fitted successfully;

[0057] The determination module is used to determine whether the fuse meets the design requirements based on the estimated number of fuse lifespans.

[0058] Another object of the present invention is to provide a design system for relays and fuses in a power battery system, comprising:

[0059] Memory;

[0060] a processor coupled to the memory; and

[0061] A computer program stored in the memory and running on the processor, wherein the running of the computer program leads to the execution of the design method of relays and fuses in the power battery system according to the above-mentioned method.

[0062] The design method of the present invention performs matching verification on relays and fuses and estimates the life of fuses in the early stage of power battery system design. The estimation result is more accurate, direct and quicker than the prior art. It can not only ensure the rationality of the design, but also avoid safety problems caused by mismatch between relay and fuse design and unsatisfactory fuse life, thereby improving the safety and reliability of the power battery system.

[0063] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0065] Figure 1 A schematic diagram of a design method for relays and fuses in a power battery system in an embodiment of the present invention is shown;

[0066] Figure 2 An electrical schematic diagram of a power battery system in an embodiment of the present invention is shown;

[0067] Figure 3 A schematic diagram of the matching and fitting steps of a relay and a fuse in an embodiment of the present invention is shown;

[0068] Figure 4 A schematic diagram of the fitting results of the time-current curves of a relay and a fuse in an embodiment of the present invention is shown;

[0069] Figure 5 A schematic diagram of fuse life estimation results in an embodiment of the present invention is shown;

[0070] Figure 6 A schematic diagram of the design system structure of relays and fuses in a power battery system in an embodiment of the present invention is shown;

[0071] Figure 7A schematic diagram of the design system structure of relays and fuses in another power battery system in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] like Figure 1 As shown, an embodiment of the present invention introduces a design method for relays and fuses in a power battery system, and the design method includes, first, obtaining the current parameters and correction parameters of the power battery system; second, selecting the relay model based on the obtained current parameters, and selecting the fuse model based on the obtained current parameters and correction parameters; then, matching and fitting the selected relay and fuse, if the matching and fitting of the relay and the fuse are successful, the number of fuse life is estimated under the peak current time. Finally, based on the estimated number of fuse life, determine whether the fuse meets the design requirements. In the early stage of the design of the power battery system solution, the relay and fuse are matched and checked, and the fuse life is estimated to realize the design of the relay and fuse. The estimation result is more accurate, direct and quick than the prior art, which can not only ensure the rationality of the design, but also avoid the safety problems caused by the mismatch between the relay and the fuse design and the unsatisfactory fuse life.

[0074] Exemplarily, in the embodiments of the present invention, Figure 2 The power battery system shown in the figure is described, and the power battery system includes a battery cell, a main fuse (i.e. Figure 2 Main fuse), shunt, pre-charge relay K3, pre-charge resistor, main positive relay K2, main negative relay K1, heating relay K4, fast charge relay K5, heating system (i.e. Figure 2The positive electrode of the battery cell is connected to the first end of the main fuse, the second end of the main fuse is connected to the input end of the main positive relay K2, the output end of the main positive relay K2 is connected to the discharge plug-in of the power battery system and the positive output end of the slow charging plug-in, and the pre-charging relay K3 is connected in parallel with the main positive relay K2 and in series with the pre-charging resistor. The negative pole of the battery cell is connected to the input end of the shunt, the output end of the shunt is connected to the input end of the main negative relay K1, the output end of the main negative relay K1 is connected to the negative output end of the power battery system discharge plug-in and the slow charging plug-in, the input end of the fast charging relay K5 is connected to the output end of the main positive relay K2, the output end of the fast charging relay K5 is connected to the positive output end of the power battery system fast charging plug-in, the negative output end of the fast charging plug-in is connected to the output end of the main negative relay K1, the input end of the heating relay K4 is connected to the output end of the main positive relay K2, the output end of the heating relay K4 is connected to the input end of the heating system (i.e., the heating film in the figure) through a fuse (fuse in the figure), and the output end of the heating system is connected to the output end of the main negative relay K1. The design method in the embodiment of the present invention is adopted, that is, Figure 2 Matching design is performed between the main positive relay, main negative relay and / or fast charging relay and the main fuse.

[0075] like Figure 3 As shown, the design method of relays and fuses in the power battery system includes the matching design of relays and fuses in the power battery system and the estimation of fuse life, which specifically includes three parts, namely: power battery system current calculation, relay and fuse selection, and relay and fuse matching design and fuse life estimation. Specifically, the first part, power battery system current calculation, that is, obtaining the current parameters and correction parameters of the power battery system, includes power battery system rated power collection, rated voltage calculation, system total internal resistance calculation, power battery system peak power collection, peak voltage calculation and system total internal resistance calculation. Specifically, obtaining the current parameters of the power battery system includes, first, based on the MAP (Map of State-variables and Performance: a mathematical model or data table used to describe the steady-state characteristic parameters of the battery) table of the power battery system, obtaining one or more of the following system parameters: the total number of series and total parallel numbers of battery cells in the power battery system, the internal resistance of the battery cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connecting parts, the rated power of the power battery system, the cell OCV voltage (Open Circuit Voltage: open circuit voltage) at the corresponding rated power, the peak power of the power battery system, and the cell OCV voltage at the corresponding peak power; further, the peak power includes the maximum peak power under unlimited power. R 电器件The R of a single electrical component can be obtained from its specification sheet. 接触电阻 It is obtained by accumulating the contact resistance of all connection points in the power battery system, and the single contact resistance value is assigned based on experience.

[0076] Then, based on the acquired one or more system parameters, the rated current and peak current of the power battery system are calculated.

[0077] Specifically, the rated power, peak power, open circuit voltage and internal resistance of the battery cell at two powers of the power battery system are obtained from MAP. The voltage U of the power battery system and the total DC internal resistance R of the power battery system are 总 And the relationship between the output power P of the power battery system satisfies:

[0078] P=UI-I 2 R 总 (1)

[0079] U=U cell ×n s (2)

[0080]

[0081] Where U is the voltage of the power battery system (rated voltage is calculated at rated power, and peak voltage is calculated at peak power), U cell is the cell OCV voltage, n s is the total number of battery strings in the power battery system (i.e. the total number of cells connected in series), and the total DC internal resistance of the power battery system R 总 is the total internal resistance of the battery cell and the total internal resistance of the copper and aluminum busbars of the connecting parts R 铝铜排 、Total internal resistance of all electrical components R 电器件 And the total contact resistance R of all bolted connection points 接触电阻 The sum of the internal resistance of the connection points in the power battery system, R cell is the internal resistance of the cell, n p is the total number of parallel cells in the power battery system (i.e., the total number of cells in parallel), ρ is the resistivity of the connector (i.e., copper-aluminum bar), L is the length of the copper-aluminum bar of the connector, S is the cross-sectional area of ​​the copper-aluminum bar of the connector, P is the output power of the power battery system, UI is the total power of the power battery system, I 2 R 总 is the power consumed by the internal resistance of the power battery system, and I is the current value of the power battery system.

[0082] In the embodiment of the present invention, the above formula is used to calculate the rated current at the rated power, including:

[0083] First, the open circuit voltage of the battery cell at rated power and the total number of battery cells in the power battery system are substituted into formula (2) to calculate the voltage of the power battery system at rated power.

[0084] Then, the total number of series and parallel cells of the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection parts are substituted into formula (3) to calculate R 总 ;

[0085] Finally, the rated power of the power battery system, the calculated voltage of the power battery system at the rated power, and R 总 Substitute into formula (1) to calculate the rated current of the power battery system.

[0086] Using the above formula, the rated current at peak power is calculated to include,

[0087] First, the open circuit voltage of the battery cell at peak power and the total number of battery cells in the power battery system are substituted into formula (2) to calculate the voltage of the power battery system at peak power.

[0088] Then, the total number of series and parallel cells of the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection parts are substituted into formula (3) to calculate R 总 ;

[0089] Finally, the peak power of the power battery system, the calculated power battery system voltage at the peak power, and R 总 Substitute into formula (1) to calculate the peak current of the power battery system.

[0090] For example, in the embodiment of the present invention, the power battery system single cell adopts lithium iron phosphate square shell battery, the power battery system is composed of 1 parallel and 114 series, its rated power is 62kW, the open circuit voltage of the cell at rated power is 3.21V (volts), and the internal resistance of the cell is 1.08mΩ (milliohms); the peak power of 10S (i.e., the peak current time) is 181kW (kilowatts), the open circuit voltage of the cell at peak power is 3.325V, and the internal resistance of the cell is 0.8mΩ. Therefore, substituting the above information into the above formula, the rated current of the power battery system is 176A, and the peak current of 10S is 550A.

[0091] The second part, relay and fuse selection, includes relay selection and fuse selection. Specifically, selecting a relay model based on the current parameters of the power battery system includes selecting a relay according to the rated current and peak current of the power battery system. Among them, continuing to use the above-calculated rated current of the power battery system of 176A and 10S peak current of 550A as an example, the rated current is 176A and the 10S peak current is 550A. The Hongfa HFE82V-200B / 750-12-HC5 relay ( Figure 4 The rated current and peak current of the HFE82V-200B / 750-12-HC5 relay are consistent with the calculated parameters, that is, a relay whose rated current and peak current are consistent with the calculated rated current and peak current is selected.

[0092] Select the fuse model based on the obtained current parameters and correction parameters, including obtaining the power battery system correction parameters, including obtaining the following correction factors: the correction factor K of the ambient temperature t , Thermal connection correction factor K e , Air cooling correction factor K v , frequency correction factor K f , fuse system number K b Furthermore, the multiple correction coefficients are correction coefficients for abnormal use conditions. The fuse is selected according to the correction coefficient for abnormal use conditions, wherein the relationship between the rated current of the power battery system and the rated current of the fuse and the correction coefficient for abnormal use conditions satisfies:

[0093] I b =I n ×K t ×K e ×K v ×K f ×K b

[0094] Among them, I b is the rated current in the power battery system, I n is the rated current of the fuse, and the correction factor for abnormal use conditions includes K t is the correction factor for ambient temperature, K e is the thermal connection correction factor, K v is the air cooling correction factor, K f is the frequency correction factor, K b is the fuse tube system parameter. Furthermore, when the fuse tube body is a ceramic fuse tube body, K b The value can be 1.0. When the fuse body is a fiber fuse, K b The value may be 0.8, but is not limited thereto, and other values ​​are also applicable to the present invention.

[0095] Then, the various correction factors and rated currents obtained are substituted into formula (4) to calculate the rated current I of the fuse. n ;Select I n A fuse with a current value greater than or equal to a preset rated current value. Continuing with the above-calculated power battery system rated current of 176A and 10S peak current of 550A, I b is 176A, and I is calculated based on the above-mentioned relevant correction coefficients. n ≥ preset rated current value, the preset rated current value may be 325A, but is not limited thereto, and may also be other preset values, for example, I n ≥325A, the initial choice is Zhongrong RS309-MD-EV400A.

[0096] The third part is to match the selected relay and fuse, including matching and fitting based on the time and current parameters of the selected relay and fuse. Specifically, first, the time and current parameter curve of the relay and the time and current parameter curve of the fuse are obtained respectively; then, the obtained time and current parameter curve of the relay is matched and fitted with the time and current parameter curve of the fuse, wherein, if after the maximum cut-off current of the selected relay, the trend of the time and current parameter curve of the relay and the fuse shows that the fuse tolerance time is less than the relay tolerance time, then the matching and fitting of the selected fuse and relay is successful. For example, as Figure 4 As shown, the maximum cut-off current of the selected relay is 1100A (ampere), but it is not limited to this. Depending on the model, application system and scenario, the maximum cut-off current may also be 900A, etc. After 1100A, the time-current curve of the fuse is always below the time-current curve of the relay, that is, the fuse tolerance time is less than the relay tolerance time, so the relay and fuse selected above match. If after the maximum cut-off current of the selected relay, the trend of the time and current parameter curves of the relay and the fuse shows that the fuse tolerance time is not less than the relay tolerance time, then the matching fitting of the selected fuse and relay fails, and the fuse is reselected, and then the matching fitting steps are performed. The design purpose of the fuse protection relay is achieved through matching design in the case of large current short circuit, which ensures the safety and reliability of the operation of the power battery system.

[0097] In an embodiment of the present invention, the design method further includes recording time and current parameters of relays of different specifications and time and current parameters of fuses of different specifications before matching and fitting the selected relays and fuses, which can be manually entered.

[0098] Further, the fuse life estimation, that is, if the selected relay and the time and current parameters of the fuse are matched and fitted successfully, the fuse life times under the peak current time are estimated, first, the ratio of the peak current and the peak current time of the fuse impulse current is obtained; then, the obtained ratio is compared with the preset value in the fuse life times library to obtain the fuse life times. Figure 5 As shown, it includes the current ratio and the fuse life times library. Under the peak current time of 10S (S represents the time parameter), 1400A is the current value that the selected fuse can withstand, that is, the impact current (also called withstand current). The corresponding peak current of RS309-MD-EV400A is 550A, 550 / 1400=0.40. According to the ratio result, the corresponding fuse peak current life library is queried. Figure 5 In the figure, 0.4 corresponds to 50,000 times, which means that the model of fuse can withstand the impact of peak current overload for about 50,000 times. Then, based on the estimated number of fuse life times, determining whether the fuse meets the design requirements includes: if the estimated number of fuse life times is greater than the preset number of times, the fuse meets the design requirements; otherwise, the fuse does not meet the design requirements, and the relay and the fuse are reselected. The above 50,000 times is greater than the preset number of 10,000 times, which meets the project requirements. The preset number is not limited to 10,000 times, and the preset number of 20,000 times according to project requirements is also applicable to the present invention.

[0099] By matching the relays and fuses in the power battery system and estimating the fuse life, not only can the rationality of the design be guaranteed, but safety problems caused by design mismatch and unsatisfactory life can also be avoided, thereby improving the reliability and safety of the power battery system.

[0100] like Figure 6 As shown, in an embodiment of the present invention, a design system for relays and fuses in a power battery system capable of executing the above-mentioned design method is introduced, and the system includes an acquisition module, a selection module, a matching module, and an estimation module, wherein the acquisition module is used to acquire the current parameters and correction parameters of the power battery system; the selection module is used to select the relay model based on the acquired current parameters of the power battery system, and the fuse model based on the acquired current parameters and correction parameters; the matching module is used to match and fit the selected relay and fuse; the estimation module is used to estimate the number of fuse life under the peak current time if the matching and fitting of the relay and the fuse are successful; the determination module is used to determine whether the fuse meets the design requirements based on the estimated number of fuse life. The above-mentioned system matches the relay and fuse of the power battery system and estimates the fuse life in the early stage of the power battery system design, which ensures the rationality of the design and the accuracy of the estimation, and the estimation method is simple and fast, which improves the reliability and safety of the power battery system.

[0101] like Figure 7 As shown, the embodiment of the present invention also introduces a design system for relays and fuses in a power battery system that can execute the above-mentioned design method, the system includes a memory and a processor coupled to the memory; and a computer program stored in the memory and running on the processor, the running of the computer program leads to the execution of the above-mentioned design method for relays and fuses in a power battery system. In the early stage of the scheme design, the present invention can match the design of relays and fuses of the power battery system and estimate the fuse life in the early stage of the scheme design of the power battery system, while ensuring the rationality of the design and the accuracy of the estimation, and the estimation method is simple and fast.

[0102] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0103] This application is a process of referring to the method, device (system), and computer program product according to the embodiments of the present application

[0104] The flowchart and / or block diagram are described in detail. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0105] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0106] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A box or steps to the function specified in the box.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not deviate from the spirit and scope of the present invention should be included in the protection scope of the claims of the present invention. The above content is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

[0108] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for relays and fuses in a power battery system, characterized in that: include, Obtain current parameters and correction parameters of the power battery system; Selecting a relay model based on the acquired current parameter, and selecting a fuse model based on the acquired current parameter and the correction parameter; The selected relay and fuse are matched and fitted. If the relay and fuse are matched and fitted successfully, the number of fuse life times is estimated under the peak current time; Based on the estimated fuse life times, determine whether the fuse meets the design requirements.

2. The design method of relays and fuses in a power battery system according to claim 1, characterized in that: Obtaining the current parameters of the power battery system includes: Based on the MAP table of the power battery system, obtain one or more of the following system parameters: The total number of cells in series and parallel in the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection parts, the rated power of the power battery system, the open-circuit voltage of the cells at the rated power, the peak power of the power battery system, and the open-circuit voltage of the cells at the peak power; Based on the obtained one or more system parameters, the rated current and peak current of the power battery system are calculated.

3. The design method of relays and fuses in a power battery system according to claim 2, characterized in that: Based on the obtained one or more system parameters, the rated current and peak current of the power battery system are calculated, including: Determine the voltage U of the power battery system and the total DC internal resistance R of the power battery system 总 And the relationship between the output power P of the power battery system: P=UI-I 2 R 总 (1) Where P is the output power of the power battery system, U is the voltage of the power battery system, I is the current value of the power battery system, R 总 is the total DC internal resistance of the power battery system, where: U=U cell ×n S (2) Where U cell is the open circuit voltage of the cell, n s The total number of battery cells in the power battery system; In the formula, R 电芯总 is the total internal resistance of the cell, R 铝铜排 is the total internal resistance of the copper and aluminum bars of the connector, R 电器件 is the total internal resistance of all electrical components and R 接触电阻 is the total contact resistance of all bolted connection points, R cell is the internal resistance of the cell, n p is the total number of cells in the power battery system, ρ is the resistivity of the copper-aluminum bar of the connecting piece, L is the length of the copper-aluminum bar of the connecting piece, and S is the cross-sectional area of ​​the copper-aluminum bar of the connecting piece.

4. The design method of relays and fuses in a power battery system according to claim 3, characterized in that: Based on the obtained one or more system parameters, the rated current of the power battery system is calculated, and further includes: Substitute the open circuit voltage of the battery cell at rated power and the total number of battery cells in the power battery system into formula (2) to calculate the voltage of the power battery system at rated power; Substitute the total number of series and parallel cells of the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection into formula (3) to calculate R 总 ; The rated power of the power battery system, the voltage of the power battery system at the calculated rated power, and R 总 Substitute into formula (1) to calculate the rated current of the power battery system.

5. The design method of relays and fuses in a power battery system according to claim 4, characterized in that: Based on the obtained one or more system parameters, calculating the peak current of the power battery system also includes: Substitute the open circuit voltage of the battery cell at peak power and the total number of battery cells in the power battery system into formula (2) to calculate the voltage of the power battery system at peak power; Substitute the total number of series and parallel cells of the power battery system, the internal resistance of the cells, the resistance of one or more electrical components, the contact resistance of one or more bolt connection points, the resistivity, length and cross-sectional area of ​​the copper and aluminum bars of the connection into formula (3) to calculate R 总 ; The peak power of the power battery system, the calculated power battery system voltage at the peak power, and R 总 Substitute into formula (1) to calculate the peak current of the power battery system.

6. The design method of relays and fuses in a power battery system according to any one of claims 2 to 5, characterized in that: Obtaining the power battery system correction parameters includes obtaining the following correction coefficients: Correction factor K for ambient temperature t , Thermal connection correction factor K e , Air cooling correction factor K v , frequency correction factor K f , fuse system number K b .

7. The design method of relays and fuses in a power battery system according to claim 5, characterized in that: The relay models selected based on the current parameters of the power battery system include: Select a relay whose rated current and peak current agree with the calculated rated current and peak current.

8. The design method of relays and fuses in a power battery system according to claim 7, characterized in that: The fuse model selection based on the obtained current parameters and correction parameters includes: Determine the relationship between the rated current of the power battery system and the rated current and correction parameters of the fuse: I b =I n ×K t ×K e ×K v ×K f ×K b (4) Among them, I b is the rated current of the power battery system, I n is the rated current of the fuse, and the correction parameters include K t is the correction factor for ambient temperature, K e is the thermal connection correction factor, K v is the air cooling correction factor, K f is the frequency correction factor, K b is the fuse system number; Substitute the various correction factors and rated currents obtained into formula (4) to calculate the rated current I of the fuse. n ; Select I n A fuse with a current rating greater than or equal to the preset current rating.

9. The design method of relays and fuses in a power battery system according to claim 8, characterized in that: Matching the selected relays and fuses includes: Obtain time and current parameter curves of the selected relay and fuse respectively; Based on the maximum cut-off current of the relay selected by the power battery system and the time and current parameter curves of the selected relay and fuse, it is determined whether the selected fuse and relay match each other. If, after the maximum cut-off current of the selected relay, the time and current parameter curves of the relay and the fuse show that the fuse withstand time is less than the relay withstand time, the selected fuse and relay match fitting is successful; Otherwise, the selected fuse and relay fail to match each other, and the fuse must be reselected.

10. The design method of relays and fuses in a power battery system according to claim 9, characterized in that: Before matching and fitting the selected relays and fuses, the time and current parameters of relays of different specifications and the time and current parameters of fuses of different specifications are also collected.

11. The design method of relays and fuses in a power battery system according to claim 9, characterized in that: If the relay and fuse are matched successfully, the estimated fuse life times under peak current time include: Obtain the ratio of the fuse's impulse current resistance under peak current and peak current time; Based on the obtained ratio, the fuse life times are obtained from the fuse life times library.

12. The design method of relays and fuses in a power battery system according to claim 11, characterized in that: Based on the estimated fuse life times, determine whether the fuse meets the design requirements including, If the estimated number of fuse life cycles is greater than the preset number, the fuse meets the design requirements; Otherwise, the fuse does not meet the design requirements, and the relay and fuse should be reselected.

13. A design system for relays and fuses in a power battery system, characterized in that: include, An acquisition module, used to acquire current parameters and correction parameters of a power battery system; A selection module, for selecting a relay model based on the acquired current parameters, and for selecting a fuse model based on the acquired current parameters and correction parameters; A matching module is used to match the selected relay and fuse; An estimation module, used for estimating the number of fuse life times under the peak current time if the relay and the fuse are matched and fitted successfully; The determination module is used to determine whether the fuse meets the design requirements based on the estimated number of fuse lifespans.

14. A design system for relays and fuses in a power battery system, characterized in that: include, Memory; a processor coupled to the memory; as well as A computer program stored in the memory and running on the processor, wherein the running of the computer program results in the execution of the method for designing relays and fuses in a power battery system according to any one of claims 1 to 12.

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