A control strategy for a dual-battery pack battery system

Abstract

The present invention provides a dual-battery pack system control strategy, which includes a battery system operating mode identification method, a power-on control method, a normal battery pack power-off control method, and a fault power-off control method. The power-on control method includes a single-pack high-voltage control method and a dual-pack high-voltage control method. The normal battery pack power-off control method includes a single-pack normal power-off control method and a dual-pack normal power-off control method. The fault power-off control method includes a single-pack fault power-off control method and a dual-pack fault power-off control method. The two battery packs of the present invention are independently controlled by two battery management systems, respectively. This allows the vehicle to operate with a single battery pack while one battery pack is faulty and requires maintenance, thereby better meeting different usage requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy vehicles, and in particular relates to a control strategy for a dual-battery pack battery system. Background Art

[0002] In the current new energy vehicle sector, particularly for terminal logistics vehicles, different user groups have varying expectations for driving range. Some are driven by cost pressures but are less demanding on range, while others operate in busy environments with continuous driving. Meanwhile, some prefer to keep their vehicles operational while a single battery pack is maintained during maintenance. Therefore, it is necessary to design a control strategy for dual-battery systems to meet the diverse demands of these complex operating conditions.

[0003] In existing dual-pack battery systems, both battery packs are controlled by the same battery management system (BMS). This prevents the vehicle from operating solely with a single battery pack. If one battery pack fails, the entire vehicle becomes inoperable, failing to meet operational needs. Therefore, how to enable a vehicle to operate with a single battery pack while one battery pack requires repair has become a pressing technical challenge for those skilled in the art. Summary of the Invention

[0004] The purpose of the present invention is to provide a dual-battery pack battery system control strategy to solve the above-mentioned technical problems in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A dual-battery pack battery system control strategy includes a battery system operating mode recognition method, the battery system operating mode recognition method comprising the following steps:

[0007] The vehicle controller sends a wake-up signal to the battery management system 1 of the first battery pack and the battery management system 2 of the second battery pack through the chassis wiring harness;

[0008] If the battery management system 1 recognizes the presence of battery pack No. 1, it sends an identification message to the battery management system 2. If the battery management system 2 recognizes the presence of battery pack No. 2, it feeds back an identification message to the battery management system 1. If the battery management system 1 receives the feedback identification message within the first set time, the vehicle controller determines that the vehicle's battery system is in a dual-battery pack working mode, and sets the battery pack No. 1 as the main pack and the battery pack No. 2 as the secondary pack. If the battery management system 2 recognizes that the battery pack No. 2 does not exist, it does not feed back an identification message to the battery management system 1. If the battery management system 1 does not receive the feedback identification message within the first set time, it determines that the vehicle's battery system is in a single-battery pack working mode, and sets the battery pack No. 1 as the main pack.

[0009] If battery management system 1 identifies that battery pack No. 1 does not exist, it will not send an identification message to battery management system 2. If battery management system 2 identifies that battery pack No. 2 exists, and battery management system 2 does not receive the identification message sent by battery management system 1 within the first set time, it will determine that the vehicle's battery system is in single battery pack working mode, and battery pack No. 2 is set as the main pack.

[0010] Preferably, it further includes a power-on control method, which includes:

[0011] First, determine whether the battery system is in a dual-battery pack operating mode or a single-battery pack operating mode according to the above-mentioned battery system operating mode identification method;

[0012] If it is a single battery pack working mode, the single pack high voltage control method is executed; if it is a dual battery pack working mode, the dual pack high voltage control method is executed.

[0013] Preferably, the single package high voltage control method comprises the following steps:

[0014] Close the main negative relay of the main package;

[0015] Close the main package pre-charge relay;

[0016] Close the main positive relay of the main package;

[0017] Disconnect the main package pre-charge relay and complete the high voltage on the single package.

[0018] Preferably, the double-package high-voltage control method includes the following steps:

[0019] Step S1: Determine whether the absolute value of the difference between the main package voltage and the secondary package voltage is not greater than the set value.

[0020] If yes, when the voltage of the main package is greater than the voltage of the secondary package, execute step S2; if the voltage of the main package is not greater than the voltage of the secondary package, execute step S3;

[0021] If not, when the voltage of the main package is greater than the voltage of the secondary package, execute step S4; when the voltage of the main package is not greater than the voltage of the secondary package, execute step S5;

[0022] Step S2 includes:

[0023] Step S21, closing the main negative relay of the main package;

[0024] Step S22: close the main pack pre-charge relay;

[0025] Step S23: Determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, execute step S24; if not, enter the high pressure process of the secondary package and execute step S25.

[0026] Step S24 includes:

[0027] Step S241: close the main positive relay of the main pack and disconnect the pre-charge relay of the secondary pack after a second set time delay;

[0028] Step S242, close the secondary pack main negative relay;

[0029] Step S243, closing the secondary pack pre-charging relay;

[0030] Step S244: Determine whether the total pressure of the slave pack LINK is greater than 90% of the total pressure of its PACK. If so, close the slave pack main positive relay, delay for a second set time to disconnect the slave pack pre-charge relay, and complete the high voltage on the dual packs. If not, disconnect the slave pack main negative relay and pre-charge relay, and complete the high voltage on the single pack of the main pack.

[0031] Step S25 includes:

[0032] Step S251, disconnect the main negative relay and the pre-charge relay of the main pack;

[0033] Step S252, close the secondary pack main negative relay;

[0034] Step S253: close the secondary pack pre-charge relay;

[0035] Step S254: determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of PACK. If so, the high pressure of the secondary package is completed.

[0036] Step S3 includes:

[0037] Step S31, closing the secondary pack main negative relay;

[0038] Step S32, closing the secondary pack pre-charging relay;

[0039] Step S33: Determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, execute step S34; if not, enter the main package single package high pressure process and execute step S35;

[0040] Step S34 includes:

[0041] Step S341, close the secondary pack main positive relay, delay for a second set time and disconnect the secondary pack pre-charge relay;

[0042] Step S342, close the main negative relay of the main package;

[0043] Step S343: close the main pack pre-charge relay;

[0044] Step S344: Determine whether the total LINK pressure of the main pack is greater than 90% of the total PACK pressure. If so, close the main positive relay of the main pack, delay for a second set time to disconnect the pre-charge relay of the secondary pack, and complete the high voltage application of the dual packs. If not, disconnect the main negative relay and pre-charge relay of the main pack, and complete the high voltage application of the single pack of the secondary pack.

[0045] Step S35 includes:

[0046] Step S351, disconnect the secondary pack main negative relay and the pre-charge relay;

[0047] Step S352, close the main negative relay of the main package;

[0048] Step S353: close the main pack pre-charge relay;

[0049] Step S354: determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If so, the high pressure of the main package is completed.

[0050] Step S4 includes:

[0051] Step S41, closing the main negative relay of the main package;

[0052] Step S42: close the main pack pre-charge relay;

[0053] Step S43: Determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, execute step S44; if not, enter the high pressure process of the secondary package and execute step S45.

[0054] Step S44 includes:

[0055] Step S441, close the main positive relay of the main pack, and disconnect the pre-charge relay of the secondary pack after a second set time delay;

[0056] Step S442: Determine whether the following conditions are met: the vehicle is currently in neutral, the absolute value of the voltage difference between the main pack and the auxiliary pack is ≤ the set value, and the bus current is ≤ 3A. If so, execute step S443; if not, make corresponding adjustments to meet the conditions.

[0057] Step S443, close the secondary pack main negative relay;

[0058] Step S444: close the secondary pack pre-charge relay;

[0059] Step S445: Determine whether the total LINK pressure of the secondary pack is greater than 90% of its total PACK pressure. If so, close the secondary pack's main positive relay, delay for a second set time to disconnect the secondary pack's pre-charge relay, and complete the high voltage application of the dual packs. If not, disconnect the secondary pack's main negative relay and pre-charge relay, and complete the high voltage application of the primary pack's single pack.

[0060] Step S45 includes:

[0061] Step S451, disconnect the main negative relay and pre-charge relay of the main pack;

[0062] Step S452, close the secondary pack main negative relay;

[0063] Step S453: close the secondary pack pre-charge relay;

[0064] Step S454: determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, the high pressure of the secondary package is completed;

[0065] Step S5 includes:

[0066] Step S51, closing the secondary pack main negative relay;

[0067] Step S52: close the secondary pack pre-charge relay;

[0068] Step S53: Determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, execute step S54; if not, enter the main package single package high pressure process and execute step S55;

[0069] Step S54 includes:

[0070] Step S541, close the main positive relay of the secondary pack, and open the secondary pack pre-charge relay after a second set time delay;

[0071] Step S542: Determine whether the following conditions are met: the vehicle is currently in neutral, the absolute value of the voltage difference between the main and auxiliary packs is ≤ the set value, and the bus current is ≤ 3A. If so, execute step 543; if not, make corresponding adjustments to meet the conditions.

[0072] Step S543, close the main negative relay of the main package;

[0073] Step S544: close the main pack pre-charge relay;

[0074] Step S545: Determine whether the total LINK pressure of the main pack is greater than 90% of the total PACK pressure. If so, close the main positive relay of the main pack, delay for a second set time to disconnect the pre-charge relay of the secondary pack, and complete the high voltage application of the dual packs. If not, disconnect the main negative relay and pre-charge relay of the main pack, and complete the high voltage application of the single pack of the secondary pack.

[0075] Step S55 includes:

[0076] Step S551, disconnect the secondary pack main negative relay and the pre-charge relay;

[0077] Step S552, close the main negative relay of the main package;

[0078] Step S553: ​​close the main pack pre-charge relay;

[0079] Step S554: determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If so, the high pressure of the main package is completed.

[0080] Preferably, it also includes a normal power-off control method for the battery pack, and the normal power-off control method for the battery pack includes the following steps:

[0081] After receiving the high voltage command, first determine whether the battery system is in dual battery pack working mode or single battery pack working mode according to the above battery system working mode identification method;

[0082] If it is a single battery pack working mode, the single pack normal power-off control method is executed; if it is a dual battery pack working mode, the dual pack normal power-off control method is executed.

[0083] Preferably, the single-packet normal power-off control method includes the following steps:

[0084] Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relay of the high-voltage battery pack. If not, disconnect the main positive relay of the high-voltage battery pack after a delay of 10s.

[0085] Disconnect the main negative relay of the upper high voltage battery pack to complete the lower high voltage.

[0086] Preferably, the dual-packet normal power-off control method includes the following steps:

[0087] Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relays of all battery packs. If not, disconnect the main positive relays of all battery packs after a delay of 10s.

[0088] Disconnect the main negative relays of all battery packs and complete the high voltage reduction.

[0089] Preferably, it also includes a fault power-off control method, which includes the following steps:

[0090] Determining whether the battery system is in a dual-battery pack operating mode or a single-battery pack operating mode according to the battery system operating mode identification method;

[0091] If it is a single battery pack working mode, the single pack fault power-off control method is executed; if it is a dual battery pack working mode, the dual pack fault power-off control method is executed.

[0092] Preferably, the single-packet fault power-off control method includes the following steps:

[0093] The vehicle controller sends a high-voltage command;

[0094] The battery management system of the high-voltage battery pack receives a low-voltage instruction within a third set time;

[0095] Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relay of the high-voltage battery pack; if not, disconnect the main positive relay of the high-voltage battery pack after a delay of 10s;

[0096] Disconnect the main negative relay of the upper high voltage battery pack to complete the lower high voltage.

[0097] Preferably, the dual-packet fault power-off control method includes the following steps:

[0098] Step B1: Identify whether a single battery pack fails or both battery packs fail. If both battery packs fail, proceed to step B2; if a single battery pack fails, proceed to step B3.

[0099] Step B2 includes:

[0100] Step B21: The vehicle controller sends a high-voltage command;

[0101] Step B22: The two battery management systems receive a high voltage lowering instruction within a third set time;

[0102] Step B23: Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relays of the two battery packs; if not, disconnect the main positive relays of the two battery packs after a delay of 10s.

[0103] Step B24: Disconnect the main negative relays of the two battery packs to complete the high voltage release.

[0104] Step B3 includes:

[0105] Step B31: The vehicle controller does not send a high-voltage command, and the battery management system corresponding to the faulty battery pack controls the relay of the battery pack to disconnect, and the vehicle is adjusted to a single battery pack operation mode;

[0106] Step B32: Disconnect the main positive relay of the faulty battery pack;

[0107] Step B33: Disconnect the main negative relays of all battery packs;

[0108] Step B34: The faulty battery pack is lowered to high voltage.

[0109] The beneficial effects of the present invention are:

[0110] The dual-battery pack battery system control strategy of the present invention has two battery packs independently controlled by two battery management systems, so that when one of the battery packs of the vehicle fails and needs maintenance, the other battery pack can be used to achieve single-pack operation, thereby better meeting different usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0111] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments, and further describe the specific embodiments of the present invention in detail with reference to the drawings.

[0112] Figure 1 A flowchart of a method for identifying a battery system operating mode according to an embodiment of the present invention;

[0113] Figure 2 A flow chart of a dual-package high-voltage control method provided in an embodiment of the present invention;

[0114] Figure 3 Another flow chart of the dual-package high-voltage control method provided by an embodiment of the present invention;

[0115] Figure 4 This is a flowchart of a method for controlling power-off due to a double-packet fault provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0116] In order to enable those skilled in the art to better understand the technical solution of the present invention, the solution will be further described in detail below in conjunction with specific embodiments.

[0117] like Figure 1 As shown, an embodiment of the present invention provides a dual-battery pack battery system control strategy, which includes a battery system operating mode recognition method, and the battery system operating mode recognition method includes the following steps:

[0118] The vehicle controller sends a wake-up signal to the battery management system 1 of the first battery pack and the battery management system 2 of the second battery pack through the chassis wiring harness;

[0119] If the battery management system 1 recognizes the presence of battery pack No. 1, it sends an identification message to the battery management system 2. If the battery management system 2 recognizes the presence of battery pack No. 2, it feeds back an identification message to the battery management system 1. If the battery management system 1 receives the feedback identification message within the first set time, the vehicle controller determines that the vehicle's battery system is in a dual-battery pack working mode, and sets the battery pack No. 1 as the main pack and the battery pack No. 2 as the secondary pack. If the battery management system 2 recognizes that the battery pack No. 2 does not exist, it does not feed back an identification message to the battery management system 1. If the battery management system 1 does not receive the feedback identification message within the first set time, it determines that the vehicle's battery system is in a single-battery pack working mode, and sets the battery pack No. 1 as the main pack.

[0120] If battery management system 1 identifies that battery pack No. 1 does not exist, it will not send an identification message to battery management system 2. If battery management system 2 identifies that battery pack No. 2 exists, and battery management system 2 does not receive the identification message sent by battery management system 1 within the first set time, it will determine that the vehicle's battery system is in single battery pack working mode, and battery pack No. 2 is set as the main pack.

[0121] The dual-battery pack battery system control strategy provided by the embodiment of the present invention has a No. 1 battery pack and a No. 2 battery pack arranged in parallel, and the two battery packs are independently controlled by two battery management systems. Therefore, when one of the battery packs of the vehicle fails and requires maintenance, the other battery pack can be used to achieve single-pack operation, thereby better meeting different usage requirements.

[0122] Specifically, the first set time is 1.3 seconds to 1.7 seconds, and may be preferably 1.5 seconds.

[0123] Furthermore, the dual-battery pack battery system control strategy also includes a power-on control method, which includes:

[0124] First, determine whether the battery system is in a dual-battery pack operating mode or a single-battery pack operating mode according to the above-mentioned battery system operating mode identification method;

[0125] If it is a single battery pack working mode, the single pack high voltage control method is executed; if it is a dual battery pack working mode, the dual pack high voltage control method is executed.

[0126] Specifically, the single package high voltage control method includes the following steps:

[0127] Close the main negative relay of the main package;

[0128] Close the main package pre-charge relay;

[0129] Close the main positive relay of the main package;

[0130] Disconnect the main package pre-charge relay and complete the high voltage on the single package.

[0131] like Figure 2 and Figure 3 As shown, the double-package high-voltage control method includes the following steps:

[0132] Step S1, determining whether the absolute value of the difference between the main package voltage and the secondary package voltage is not greater than a set value, that is, whether it is less than or equal to the set value;

[0133] If yes, when the voltage of the main package is greater than the voltage of the secondary package, execute step S2; if the voltage of the main package is not greater than the voltage of the secondary package, execute step S3;

[0134] If not, when the voltage of the main package is greater than the voltage of the secondary package, execute step S4; when the voltage of the main package is not greater than the voltage of the secondary package, execute step S5;

[0135] Step S2 includes:

[0136] Step S21, closing the main negative relay of the main package;

[0137] Step S22: close the main pack pre-charge relay;

[0138] Step S23: Determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, execute step S24; if not, enter the high pressure process of the secondary package and execute step S25.

[0139] Step S24 includes:

[0140] Step S241: close the main positive relay of the main pack and disconnect the pre-charge relay of the secondary pack after a second set time delay;

[0141] Step S242, close the secondary pack main negative relay;

[0142] Step S243, closing the secondary pack pre-charging relay;

[0143] Step S244: Determine whether the total pressure of the slave pack LINK is greater than 90% of the total pressure of its PACK. If so, close the slave pack main positive relay, delay for a second set time to disconnect the slave pack pre-charge relay, and complete the high voltage on the dual packs. If not, disconnect the slave pack main negative relay and pre-charge relay, and complete the high voltage on the single pack of the main pack.

[0144] Step S25 includes:

[0145] Step S251, disconnect the main negative relay and the pre-charge relay of the main pack;

[0146] Step S252, close the secondary pack main negative relay;

[0147] Step S253: close the secondary pack pre-charge relay;

[0148] Step S254: determine whether the total pressure of the sub-pack LINK is greater than 90% of the total pressure of the PACK. If so, the high pressure of the sub-pack is completed; if not, the high pressure of the entire vehicle fails.

[0149] Step S3 includes:

[0150] Step S31, closing the secondary pack main negative relay;

[0151] Step S32, closing the secondary pack pre-charging relay;

[0152] Step S33: Determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, execute step S34; if not, enter the main package single package high pressure process and execute step S35;

[0153] Step S34 includes:

[0154] Step S341, close the secondary pack main positive relay, delay for a second set time and disconnect the secondary pack pre-charge relay;

[0155] Step S342, close the main negative relay of the main package;

[0156] Step S343: close the main pack pre-charge relay;

[0157] Step S344: Determine whether the total LINK pressure of the main pack is greater than 90% of the total PACK pressure. If so, close the main positive relay of the main pack, delay for a second set time to disconnect the pre-charge relay of the secondary pack, and complete the high voltage application of the dual packs. If not, disconnect the main negative relay and pre-charge relay of the main pack, and complete the high voltage application of the single pack of the secondary pack.

[0158] Step S35 includes:

[0159] Step S351, disconnect the secondary pack main negative relay and the pre-charge relay;

[0160] Step S352, close the main negative relay of the main package;

[0161] Step S353: close the main pack pre-charge relay;

[0162] Step S354: determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, the high pressure of the main package is completed; if not, the high pressure of the whole vehicle fails.

[0163] Step S4 includes:

[0164] Step S41, closing the main negative relay of the main package;

[0165] Step S42: close the main pack pre-charge relay;

[0166] Step S43: Determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, execute step S44; if not, enter the high pressure process of the secondary package and execute step S45.

[0167] Step S44 includes:

[0168] Step S441, close the main positive relay of the main pack, and disconnect the pre-charge relay of the secondary pack after a second set time delay;

[0169] Step S442: Determine whether the following conditions are met: the vehicle is currently in neutral, the absolute value of the difference between the main package voltage and the auxiliary package voltage is ≤ the set value, and the bus current is ≤ 3A. If so, execute step S443; if not, make corresponding adjustments to meet the conditions.

[0170] Step S443, close the secondary pack main negative relay;

[0171] Step S444: close the secondary pack pre-charge relay;

[0172] Step S445: Determine whether the total LINK pressure of the secondary pack is greater than 90% of its total PACK pressure. If so, close the secondary pack's main positive relay, delay for a second set time to disconnect the secondary pack's pre-charge relay, and complete the high voltage application of the dual packs. If not, disconnect the secondary pack's main negative relay and pre-charge relay, and complete the high voltage application of the primary pack's single pack.

[0173] Step S45 includes:

[0174] Step S451, disconnect the main negative relay and pre-charge relay of the main pack;

[0175] Step S452, close the secondary pack main negative relay;

[0176] Step S453: close the secondary pack pre-charge relay;

[0177] Step S454: determine whether the total pressure of the sub-pack LINK is greater than 90% of the total pressure of its PACK. If so, the high pressure of the sub-pack is completed; if not, the high pressure of the entire vehicle fails.

[0178] Step S5 includes:

[0179] Step S51, closing the secondary pack main negative relay;

[0180] Step S52: close the secondary pack pre-charge relay;

[0181] Step S53: Determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, execute step S54; if not, enter the main package single package high pressure process and execute step S55;

[0182] Step S54 includes:

[0183] Step S541, close the main positive relay of the secondary pack, and open the secondary pack pre-charge relay after a second set time delay;

[0184] Step S542: Determine whether the following conditions are met: the vehicle is currently in neutral, the absolute value of the voltage difference between the main and auxiliary packs is ≤ the set value, and the bus current is ≤ 3A. If so, execute step 543; if not, make corresponding adjustments to meet the conditions.

[0185] Step S543, close the main negative relay of the main package;

[0186] Step S544: close the main pack pre-charge relay;

[0187] Step S545: Determine whether the total LINK pressure of the main pack is greater than 90% of the total PACK pressure. If so, close the main positive relay of the main pack, delay for a second set time to disconnect the pre-charge relay of the secondary pack, and complete the high voltage application of the dual packs. If not, disconnect the main negative relay and pre-charge relay of the main pack, and complete the high voltage application of the single pack of the secondary pack.

[0188] Step S55 includes:

[0189] Step S551, disconnect the secondary pack main negative relay and the pre-charge relay;

[0190] Step S552, close the main negative relay of the main package;

[0191] Step S553: ​​close the main pack pre-charge relay;

[0192] Step S554: determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, the high pressure application of the main package is completed; if not, the high pressure application of the entire vehicle fails.

[0193] Specifically, the second set time may be 150 milliseconds to 250 milliseconds, and may preferably be 200 milliseconds; the set value may be 1.5V to 2.5V, and may preferably be 2V.

[0194] It can be understood that the above-mentioned LINK total pressure refers to the LINK total voltage, and the PACK total pressure refers to the PACK total voltage.

[0195] The power-on control method of the present invention first determines whether it is a dual-battery pack working mode or a single-battery pack working mode. If it is a single-battery pack working mode, the single-pack high-voltage control method is executed; if it is a dual-battery pack working mode, the dual-pack high-voltage control method is executed. At this time, it is necessary to judge the total voltage of the two battery packs to avoid the phenomenon of cross-current between the two battery packs, so the battery pack with low voltage is first put on high voltage, and then it is confirmed based on a series of judgment conditions whether the dual-pack high-voltage can be completed. If not, see whether the single-pack high-voltage can be completed. This control method can give priority to ensuring that the entire vehicle can be put on high voltage and drive normally, but if the entire vehicle does fail, it will also cause the entire vehicle to fail to put on high voltage. At the same time, if only one battery pack has a high-voltage failure, the single pack can be successfully put on high voltage at this time, but the instrument will remind the driver that there is a battery pack failure and needs to go to the service station for repair as soon as possible. Do not put on high voltage for a long time to prevent irreversible damage to the battery pack.

[0196] Furthermore, the dual-battery pack battery system control strategy also includes a battery pack normal power-off control method, and the battery pack normal power-off control method includes the following steps:

[0197] After receiving the high voltage command, first determine whether the battery system is in dual battery pack working mode or single battery pack working mode according to the above battery system working mode identification method;

[0198] If it is a single battery pack working mode, the single pack normal power-off control method is executed; if it is a dual battery pack working mode, the dual pack normal power-off control method is executed.

[0199] Specifically, the single-packet normal power-off control method includes the following steps:

[0200] Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relay of the high-voltage battery pack. If not, disconnect the main positive relay of the high-voltage battery pack after a delay of 10s.

[0201] Disconnect the main negative relay of the upper high voltage battery pack to complete the lower high voltage.

[0202] Specifically, the dual-packet normal power-off control method includes the following steps:

[0203] Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relays of all battery packs. If not, disconnect the main positive relays of all battery packs after a delay of 10s.

[0204] Disconnect the main negative relays of all battery packs and complete the high voltage reduction.

[0205] Furthermore, the dual battery pack battery system control strategy also includes a fault power-off control method,

[0206] The fault power-off control method comprises the following steps:

[0207] After identifying a level 3 fault in the battery pack, the vehicle controller will send a signal to the instrument, which will then sound an alarm through the indicator light on the instrument.

[0208] Determining whether the battery system is in a dual-battery pack operating mode or a single-battery pack operating mode according to the battery system operating mode identification method;

[0209] If it is a single battery pack working mode, the single pack fault power-off control method is executed; if it is a dual battery pack working mode, the dual pack fault power-off control method is executed.

[0210] Specifically, the single-packet fault power-off control method includes the following steps:

[0211] The vehicle controller sends a high-voltage command;

[0212] The battery management system of the high-voltage battery pack receives a high-voltage reduction instruction within a third set time; if the battery management system does not receive a high-voltage reduction instruction within the third set time, it will be forced to enter the vehicle high-voltage reduction process;

[0213] Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relay of the high-voltage battery pack; if not, disconnect the main positive relay of the high-voltage battery pack after a delay of 10s;

[0214] Disconnect the main negative relay of the upper high voltage battery pack to complete the lower high voltage.

[0215] like Figure 4 As shown, the dual-packet fault power-off control method includes the following steps:

[0216] Step B1: Identify whether a single battery pack or both battery packs are faulty and provide feedback to the vehicle controller. The vehicle controller re-evaluates and decides whether to send a high-voltage command.

[0217] If both battery packs fail, proceed to step B2; if only one battery pack fails, proceed to step B3;

[0218] Step B2 includes:

[0219] Step B21: The vehicle controller sends a high-voltage command;

[0220] Step B22: The two battery management systems receive a high-voltage reduction instruction within a third set time. If the battery management system does not receive a high-voltage reduction instruction within the third set time, the vehicle will be forced to enter the high-voltage reduction process.

[0221] Step B23: Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relays of the two battery packs; if not, disconnect the main positive relays of the two battery packs after a delay of 10s.

[0222] Step B24: Disconnect the main negative relays of the two battery packs to complete the high voltage release.

[0223] Step B3 includes:

[0224] Step B31: The vehicle controller does not send a high-voltage command, and the battery management system corresponding to the faulty battery pack controls the relay of the battery pack to disconnect, and the vehicle is adjusted to a single battery pack operation mode;

[0225] Step B32: Disconnect the main positive relay of the faulty battery pack;

[0226] Step B33: Disconnect the main negative relays of all battery packs;

[0227] Step B34: The faulty battery pack is lowered to high voltage.

[0228] Specifically, the third set time is 3 seconds to 7 seconds, and may be preferably 5 seconds.

[0229] If the present invention is powered off normally or due to a fault (a fault occurs in the single battery pack working mode, and both battery packs fail in the dual battery pack working mode), all relays will be disconnected at this time, and the instrument will light up the indicator light to alarm; if it is in the dual battery pack working mode, but only one battery pack fails, the vehicle controller will not send a high-voltage command at this time, and the battery management system will automatically control the relay of the corresponding faulty battery pack to disconnect. At the same time, the whole vehicle enters the single battery pack working mode, and the instrument will remind the driver that there is a battery pack fault and he needs to go to the service station for repair as soon as possible, and he should not use high voltage for a long time.

[0230] The present invention utilizes two battery packs connected in parallel, allowing for the selection of an appropriate power level through vehicle-matching design. Each battery pack also incorporates its own complete battery management system for control. By automatically identifying the battery system's operating mode, the present invention effectively addresses the current issue of dual battery packs requiring serial installation and inability to interchange, significantly improving after-sales serviceability. Furthermore, through power-on and power-off control, the present invention effectively ensures that if only one battery pack fails or is unable to provide high voltage, the other can remain operational.

[0231] The above are only preferred embodiments of the present invention. It should be pointed out that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, after reading the contents of the present invention, relevant technical personnel in this field can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A dual battery pack battery system control strategy, characterized in that: The method includes a battery system operating mode recognition method, which includes the following steps: The vehicle controller sends a wake-up signal to the battery management system 1 of the first battery pack and the battery management system 2 of the second battery pack through the chassis wiring harness; If the battery management system 1 recognizes the presence of battery pack No. 1, it sends an identification message to the battery management system 2. If the battery management system 2 recognizes the presence of battery pack No. 2, it feeds back an identification message to the battery management system 1. If the battery management system 1 receives the feedback identification message within the first set time, the vehicle controller determines that the vehicle's battery system is in a dual-battery pack working mode, and sets the battery pack No. 1 as the main pack and the battery pack No. 2 as the secondary pack. If the battery management system 2 recognizes that the battery pack No. 2 does not exist, it does not feed back an identification message to the battery management system 1. If the battery management system 1 does not receive the feedback identification message within the first set time, it determines that the vehicle's battery system is in a single-battery pack working mode, and sets the battery pack No. 1 as the main pack. If the battery management system 1 recognizes that the No. 1 battery pack does not exist, it does not send an identification message to the battery management system 2. If the battery management system 2 recognizes that the No. 2 battery pack exists, and the battery management system 2 does not receive the identification message sent by the battery management system 1 within the first set time, it determines that the vehicle's battery system is in a single battery pack operating mode and sets the No. 2 battery pack as the main pack; The invention also includes a normal power-off control method for the battery pack, which includes the following steps: After receiving the high voltage command, first determine whether the battery system is in dual battery pack working mode or single battery pack working mode according to the above battery system working mode identification method; If it is a single battery pack working mode, the single pack normal power-off control method is executed; if it is a dual battery pack working mode, the dual pack normal power-off control method is executed; The normal power-off control method for a single packet includes the following steps: Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relay of the high-voltage battery pack. If not, disconnect the main positive relay of the high-voltage battery pack after a delay of 10s. Disconnect the main negative relay of the battery pack with high voltage, and the high voltage is completed; The dual-packet normal power-off control method includes the following steps: Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relays of all battery packs. If not, disconnect the main positive relays of all battery packs after a delay of 10s. Disconnect the main negative relays of all battery packs and complete the high voltage reduction.

2. The dual battery pack battery system control strategy according to claim 1, characterized in that: It also includes a power-on control method, which includes: First, determine whether the battery system is in a dual-battery pack operating mode or a single-battery pack operating mode according to the above-mentioned battery system operating mode identification method; If it is a single battery pack working mode, the single pack high voltage control method is executed; if it is a dual battery pack working mode, the dual pack high voltage control method is executed.

3. The dual battery pack battery system control strategy according to claim 2, characterized in that: The single package high voltage control method comprises the following steps: Close the main negative relay of the main package; Close the main package pre-charge relay; Close the main positive relay of the main package; Disconnect the main package pre-charge relay and complete the high voltage on the single package.

4. The dual battery pack battery system control strategy according to claim 2, characterized in that: The double-package upper high voltage control method comprises the following steps: Step S1: Determine whether the absolute value of the difference between the main package voltage and the secondary package voltage is not greater than the set value. If yes, when the voltage of the main package is greater than the voltage of the secondary package, execute step S2; if the voltage of the main package is not greater than the voltage of the secondary package, execute step S3; If not, when the voltage of the main package is greater than the voltage of the secondary package, execute step S4; when the voltage of the main package is not greater than the voltage of the secondary package, execute step S5; Step S2 includes: Step S21, closing the main negative relay of the main package; Step S22: close the main pack pre-charge relay; Step S23: Determine whether the total pressure of the main package LINK is greater than 90% of its total pressure of the PACK. If so, execute step S24; if not, enter the high-pressure process of the secondary package and execute step S25. Step S24 includes: Step S241: close the main positive relay of the main pack and disconnect the pre-charge relay of the secondary pack after a second set time delay; Step S242, close the secondary pack main negative relay; Step S243, closing the secondary pack pre-charging relay; Step S244: Determine whether the total pressure of the slave pack LINK is greater than 90% of the total pressure of its PACK. If so, close the slave pack's main positive relay, delay for a second set time to disconnect the slave pack's pre-charge relay, and complete the high voltage application of the dual packs. If not, disconnect the slave pack's main negative relay and pre-charge relay, and complete the high voltage application of the single pack of the main pack. Step S25 includes: Step S251, disconnect the main negative relay and the pre-charge relay of the main pack; Step S252, close the secondary pack main negative relay; Step S253: close the secondary pack pre-charge relay; Step S254: determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of PACK. If so, the high pressure of the secondary package is completed. Step S3 includes: Step S31, closing the secondary pack main negative relay; Step S32, closing the secondary pack pre-charging relay; Step S33: Determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, execute step S34; if not, enter the main package single package high pressure process and execute step S35; Step S34 includes: Step S341, close the secondary pack main positive relay, delay for a second set time and disconnect the secondary pack pre-charge relay; Step S342, close the main negative relay of the main package; Step S343: close the main pack pre-charge relay; Step S344: Determine whether the total LINK pressure of the main pack is greater than 90% of the total PACK pressure. If so, close the main positive relay of the main pack, delay for a second set time to disconnect the pre-charge relay of the secondary pack, and complete the high voltage on the dual packs. If not, disconnect the main negative relay and pre-charge relay of the main pack, and complete the high voltage on the single pack of the secondary pack. Step S35 includes: Step S351, disconnect the secondary pack main negative relay and the pre-charge relay; Step S352, close the main negative relay of the main package; Step S353: close the main pack pre-charge relay; Step S354: determine whether the total pressure of the main package LINK is greater than 90% of its total pressure of the PACK. If so, the high pressure of the main package is completed. Step S4 includes: Step S41, closing the main negative relay of the main package; Step S42: close the main pack pre-charge relay; Step S43: Determine whether the total pressure of the main package LINK is greater than 90% of the total pressure of its PACK. If yes, execute step S44; if not, enter the high pressure process of the secondary package and execute step S45. Step S44 includes: Step S441: Close the main positive relay of the main package, and disconnect the auxiliary package pre-charge relay after a second set time. electrical appliances; Step S442: determine whether the following conditions are met: the vehicle is currently in neutral, the main bag and the auxiliary bag are The absolute value of the voltage difference is less than or equal to the set value, and the bus current is less than or equal to 3A. If so, execute step S443; if not, make corresponding adjustments to meet the conditions. Step S443, close the secondary pack main negative relay; Step S444: close the secondary pack pre-charge relay; Step S445: Determine whether the total LINK pressure of the secondary pack is greater than 90% of its total PACK pressure. If so, close the secondary pack's main positive relay, delay for a second set time to disconnect the secondary pack's pre-charge relay, and complete the high voltage application of the dual packs. If not, disconnect the secondary pack's main negative relay and pre-charge relay, and complete the high voltage application of the primary pack's single pack. Step S45 includes: Step S451, disconnect the main negative relay and pre-charge relay of the main pack; Step S452, close the secondary pack main negative relay; Step S453: close the secondary pack pre-charge relay; Step S454: determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, the high pressure of the secondary package is completed; Step S5 includes: Step S51, closing the secondary pack main negative relay; Step S52: close the secondary pack pre-charge relay; Step S53: Determine whether the total pressure of the secondary package LINK is greater than 90% of the total pressure of its PACK. If so, execute step S54; if not, enter the main package single package high pressure process and execute step S55; Step S54 includes: Step S541, close the main positive relay of the secondary pack, and open the secondary pack pre-charge relay after a second set time delay; Step S542: Determine whether the following conditions are met: the vehicle is currently in neutral, the absolute value of the voltage difference between the main and auxiliary packs is ≤ the set value, and the bus current is ≤ 3A. If so, execute step 543; if not, make corresponding adjustments to meet the conditions. Step S543, close the main negative relay of the main package; Step S544: close the main pack pre-charge relay; Step S545: Determine whether the total LINK pressure of the main pack is greater than 90% of the total PACK pressure. If so, close the main positive relay of the main pack, delay for a second set time to disconnect the pre-charge relay of the secondary pack, and complete the high voltage on the dual packs. If not, disconnect the main negative relay and pre-charge relay of the main pack, and complete the high voltage on the single pack of the secondary pack. Step S55 includes: Step S551, disconnect the secondary pack main negative relay and the pre-charge relay; Step S552, close the main negative relay of the main package; Step S553: ​​close the main pack pre-charge relay; Step S554: determine whether the total pressure of the main package LINK is greater than 90% of its total pressure of the PACK. If so, the high pressure of the main package single package is completed.

5. The dual battery pack battery system control strategy according to claim 1, characterized in that: The method further includes a fault power-off control method, which includes the following steps: According to the above battery system working mode identification method, it is determined whether the battery system is in dual battery pack working mode. Mode, or single battery pack working mode; If the working mode is single battery pack, the single pack fault power-off control method is executed; if the working mode is dual battery pack, the If the double-packet working mode is used, the double-packet fault power-off control method is executed.

6. The dual battery pack battery system control strategy according to claim 5, characterized in that: The single-packet fault power-off control method includes the following steps: The vehicle controller sends a high-voltage command; The battery management system of the high-voltage battery pack receives a low-voltage instruction within a third set time; Determine whether the main circuit current is less than 10A. If so, disconnect the main positive relay of the high-voltage battery pack; if not, disconnect the main positive relay of the high-voltage battery pack after a delay of 10s; Disconnect the main negative relay of the upper high voltage battery pack to complete the lower high voltage.

7. The dual battery pack battery system control strategy according to claim 5, characterized in that: The dual packet fault power-off control method includes the following steps: Step B1: Identify whether a single battery pack fails or both battery packs fail. If both battery packs fail, proceed to step B2; if only one battery pack fails, proceed to step B3; Step B2 includes: Step B21: The vehicle controller sends a high-voltage command; Step B22: The two battery management systems receive a high voltage lowering instruction within a third set time; Step B23: Determine whether the main circuit current is less than 10A. If so, disconnect the two batteries. If not, the main positive relays of the two battery packs will be disconnected after a delay of 10s; Step B24: Disconnect the main negative relays of the two battery packs to complete the high voltage release. Step B3 includes: Step B31: The vehicle controller does not send a high voltage command, which corresponds to the faulty battery pack. The battery management system controls the relay of the battery pack to disconnect, and the vehicle is adjusted to single battery pack operation mode; Step B32: Disconnect the main positive relay of the faulty battery pack; Step B33: Disconnect the main negative relays of all battery packs; Step B34: The faulty battery pack is lowered to high voltage.

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