Control method and device of relay and battery management system

Abstract

The application provides a control method and device of a relay and a battery management system. The method comprises the following steps: determining a first threshold curve and a second threshold curve according to a current-time working condition curve provided by a whole vehicle and a working current-time curve provided by a preset relay; selecting current values of a plurality of time points corresponding to the first threshold curve and the second threshold curve as protection threshold values respectively, and calculating root mean square current values of each time point in the plurality of time points respectively; if any root mean square current value is greater than or equal to the protection threshold value of the first threshold curve at the same time point, the current is controlled to be reduced, and if any root mean square current value is greater than or equal to the protection threshold value of the second threshold curve at the same time point, the relay is controlled to be disconnected. The application compares the root mean square current value with the protection threshold value to reduce the current or disconnect the relay in time, so as to prevent the relay from overheating.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a relay control method, device and battery management system. Background Technology

[0002] A relay is an electronic control device that plays a crucial role in power batteries, providing automatic adjustment, safety protection, and circuit switching. The relay operates by closing the relay by engaging the moving contact when low voltage is applied, allowing high-voltage current to flow between the moving and stationary contacts. During the relay's operation, the coil and the contact points between the moving and stationary contacts generate Joule heat. This heat generation at the contact points increases exponentially with the power and current during battery charging and discharging.

[0003] Overheating during operation can shorten the lifespan of a relay and potentially cause it to stick together. Therefore, in practical use, monitoring the relay temperature and limiting the output power when it approaches the operating temperature limit is crucial for battery life and safety. Summary of the Invention

[0004] This application provides a relay control method, device, and battery management system to solve the problem of how to control relay overheating.

[0005] In a first aspect, this application provides a method for controlling a relay, the method comprising:

[0006] Based on the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by the preset relay, a first threshold curve and a second threshold curve are determined, wherein at the same time point, the values ​​corresponding to the current-time operating condition curve, the first threshold curve, the second threshold curve and the operating current-time curve are in an increasing relationship.

[0007] The current values ​​at multiple time points are selected from the first threshold curve and the second threshold curve respectively as protection thresholds, and the root mean square current value at each of the multiple time points is calculated respectively.

[0008] If any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, the current is controlled to decrease; and if any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point, the relay is controlled to disconnect.

[0009] In one embodiment of this application, the method further includes:

[0010] Obtain the real-time temperature T of the relay;

[0011] Configured below the upper limit of the relay's operating temperature T a The first protection temperature threshold T1 and the value below the upper limit of the relay's safe temperature T b The second protection temperature threshold T2, where T b >T2>T a >T1.

[0012] In one embodiment of this application,

[0013] If T≥T1, the current is reduced by controlling the battery management system.

[0014] If T ≥ T2, the relay is disconnected by the battery management system.

[0015] In one embodiment of this application, the first threshold curve is a current reduction protection curve, and the second threshold curve is a relay disconnection current protection curve. The step of determining the first threshold curve and the second threshold curve includes:

[0016] Select multiple corresponding time points on the current-time operating condition curve and the operating current-time curve respectively;

[0017] Based on each time point, the first threshold curve is determined at a preset first position of the distance between the current-time operating condition curve and the operating current-time curve, and the second threshold curve is determined at a preset second position of the distance between the current-time operating condition curve and the operating current-time curve.

[0018] At the same time point, the current value at the preset first position is less than the current value at the preset second position.

[0019] In one embodiment of this application, the step of selecting current values ​​at corresponding time points from the first threshold curve and the second threshold curve as protection thresholds includes:

[0020] Select t1, t2, ..., t on the first threshold curve. n The current value at a given time point is denoted as I. a (t1), I a (t2), ...I a (t n ), where n is a positive integer;

[0021] Select t1, t2, ..., t from the second threshold curve that correspond to the first threshold curve. n The time point, and the corresponding current value, represent I. b (t1), I b (t2), ...I b (t n);

[0022] Let Ia(t1), I a (t2), ...I a (t n ) as the protection threshold of the first threshold curve, and I b (t1), I b (t2), ...I b (t n () is used as the protection threshold for the second threshold curve.

[0023] In one embodiment of this application, the step of calculating the root mean square current value at each of the plurality of time points includes:

[0024] Based on each interval Δt after the battery has been operating, each interval Δt is for each time point (t1, t2, ..., t... n Perform a root mean square current calculation, specifically including:

[0025] Within a time interval Δt, for a time point t n At that time point t n If a current value is acquired at every time interval n′ during the reverse time, then N current values ​​are obtained, where N = t n / n′;

[0026] Calculate time point t using the following root mean square formula. n The root mean square current value:

[0027]

[0028] And so on, calculate t1, t2, ..., t n-1 The root mean square current values ​​corresponding to the time points are I(t1), I(t2), ..., I(t) in sequence. n-1 ).

[0029] In one embodiment of this application, the step of controlling the reduction of current if any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point includes:

[0030] If I(t1)≥I a (t1), or I(t2)≥I a (t2), or..., or I(t) n )≥I a (t n If the current is reduced, the battery management system will control the reduction of the current.

[0031] In one embodiment of this application, the step of controlling the relay to disconnect if any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point includes:

[0032] I(t1)≥I b (t1), or I(t2)≥I b (t2), or..., or I(t) n )≥I b (t n If the battery management system controls the relay to disconnect, then the relay will disconnect.

[0033] Secondly, this application also provides a control device for a relay, the device comprising:

[0034] The threshold curve determination module is used to determine a first threshold curve and a second threshold curve based on the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by the preset relay. At the same time point, the values ​​corresponding to the current-time operating condition curve, the operating current-time curve, the first threshold curve and the second threshold curve are in an increasing relationship.

[0035] The root mean square current calculation module is used to select the current values ​​at multiple time points from the first threshold curve and the second threshold curve as protection thresholds, and to calculate the root mean square current value at each of the multiple time points.

[0036] The control module is used to control the current to decrease when any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, and to control the relay to disconnect when any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point.

[0037] Thirdly, this application also provides a battery management system connected to a relay, wherein the battery management system executes a program to implement the steps of the relay control method as described in any of the first aspects.

[0038] The relay control method, device, and battery management system provided in this application determine a first threshold curve and a second threshold curve based on the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by the preset relay. The method selects the current values ​​at multiple time points from the first threshold curve and the second threshold curve as protection thresholds, and then calculates the root mean square current value at each of the multiple time points.

[0039] If the root mean square (RMS) current value at any given time point is greater than or equal to the protection threshold of the first threshold curve at that time point, the current is reduced. If the RMS current value at any given time point is greater than or equal to the protection threshold of the second threshold curve at that time point, the relay is disconnected. This application achieves timely current reduction or relay disconnection by comparing the RMS current value with the protection threshold to prevent relay overheating. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart illustrating the control method for the relay provided in this application;

[0042] Figure 2 This is a schematic diagram illustrating the selection of the protection threshold provided in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram of the relay and battery management system provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the structure of the relay control device provided in this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0047] To address the problem of relay overheating, this application provides a relay control method, device, and battery management system. The method determines a first threshold curve and a second threshold curve based on the vehicle's current-time operating condition curve and a preset relay operating current-time curve. It then selects current values ​​at multiple time points from the first and second threshold curves as protection thresholds and calculates the root mean square (RMS) current value at each of these time points. If the RMS current value at any time point is greater than or equal to the protection threshold of the first threshold curve at that time point, the current is reduced. If the RMS current value at any time point is greater than or equal to the protection threshold of the second threshold curve at that time point, the relay is disconnected. This application achieves timely current reduction or relay disconnection by comparing the RMS current value with the protection threshold, thereby preventing relay overheating.

[0048] The following is combined Figures 1-4 This application describes the relay control method, apparatus, and battery management system.

[0049] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating the relay control method provided in this application. A relay control method, the method comprising:

[0050] Step 101: Based on the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by the preset relay, determine the first threshold curve and the second threshold curve, wherein at the same time point, the values ​​corresponding to the current-time operating condition curve, the first threshold curve, the second threshold curve and the operating current-time curve are in an increasing relationship.

[0051] Step 102: Select the current values ​​of multiple time points corresponding to the first threshold curve and the second threshold curve as protection thresholds, and calculate the root mean square current value of each time point among the multiple time points.

[0052] Step 103: If any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, control to reduce the current; and if any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point, control to disconnect the relay.

[0053] The following is a detailed description of steps 101 to 103 above.

[0054] In some embodiments of this application, in step 101 above, the first threshold curve is a current reduction protection curve, and the second threshold curve is a relay disconnection current protection curve. The step of determining the first threshold curve and the second threshold curve includes:

[0055] Step 1011: Select multiple corresponding time points from the current-time operating condition curve and the operating current-time curve respectively.

[0056] The current-time operating condition curve is a curve developed and provided during the design or testing of a vehicle. This curve describes how the current changes over time under specific operating conditions. During vehicle development, various experiments and tests are conducted to obtain current data for the vehicle under different usage scenarios, and the current-time operating condition curve is derived through data analysis and processing. The current-time operating condition curve provided by the vehicle manufacturer can be used to evaluate the vehicle's performance, reliability, and the operating status of its various components.

[0057] The operating current-time curve is determined based on the specifications of each relay, showing the maximum operating current the relay can withstand at different times. For example, relay specifications may include technical parameters such as rated voltage, rated current, and power.

[0058] The current-time operating condition curve reflects the change of the vehicle's current over time, while the operating current-time curve reflects the relay's operating current capability at different times. Multiple time points are selected for both the current-time operating condition curve and the operating current-time curve. For example, t1, t2, ..., t... are selected on the vehicle's current-time operating condition curve L1. n Multiple time points are selected on the relay's operating current-time curve L2, corresponding to the current-time operating condition curve L1, i.e., t1, t2, ..., t n , where n is a positive integer.

[0059] Step 1012: Based on each time point, determine a first threshold curve at a preset first position of the distance between the current-time operating condition curve and the operating current-time curve, and determine a second threshold curve at a preset second position of the distance between the current-time operating condition curve and the operating current-time curve.

[0060] At the same time point, the current value at the preset first position is less than the current value at the preset second position.

[0061] For example, please refer to Figure 2 Based on each time point t1~t n The first threshold curve L is determined at a preset first position between the current-time operating condition curve L1 and the operating current-time curve L2. a The second threshold curve L is determined at a preset second position between the current-time operating condition curve L1 and the operating current-time curve L2. b The first preset position can be one-third of the distance, and the second preset position can be two-thirds of the distance.

[0062] It is understandable that the preset first position and preset second position can be set according to the actual scenario, and are not limited to the one-third and two-thirds positions in the example.

[0063] Steps 1011 to 1012 above involve comparing and analyzing the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by the preset relay to determine the first threshold curve and the second threshold curve, so as to establish a corresponding protection mechanism and ensure the safe operation of the relay.

[0064] Specifically, multiple current values ​​corresponding to specific time points are selected as protection thresholds. These thresholds can be used to determine whether the current exceeds the safe range. Furthermore, the first and second threshold curves reflect the minimum requirements and permissible operating range of the relay.

[0065] For example Figure 2 As shown, the curves from left to right are the current-time operating condition curve L1 and the first threshold curve L2, respectively. a Second threshold curve L b And the operating current-time curve L2, at the same time point, their corresponding values ​​show an increasing relationship. For example, at time point t1, the current value of the current-time operating condition curve L1 is less than that of the first threshold curve L. a The current value, the first threshold curve L a The current value is less than the second threshold curve L b The current value, the second threshold curve L b The current value is less than the current value of the working current-time curve L2.

[0066] In some instances of this application, step 102 above, which involves selecting current values ​​at multiple time points from the first threshold curve and the second threshold curve as protection thresholds, includes:

[0067] Step 1021: Select t1, t2, ..., t on the first threshold curve. n The current value at a given time point is denoted as I. a (t1), I a (t2), ...I a (t n ), where n is a positive integer.

[0068] Step 1022: Select t1, t2, ..., t2 corresponding to the first threshold curve on the second threshold curve. n The time point, and the corresponding current value, represent I. b (t1), I b (t2), ...I b (tn ), where n is a positive integer.

[0069] For example, n can be 10 to 15, that is, in the first threshold curve L a Second threshold curve L b Take 10 to 15 time points from each.

[0070] It should be noted that the first threshold curve L a Second threshold curve L b The corresponding time values ​​are the same, for example, the first threshold curve L. a Time point t1 and the second threshold curve L b The time t1 is the same. In addition, in order to save storage space on the battery management system for calculating the root mean square current value IRMS, the selected time points can be multiples of each other, such as 1s, 5s, 10s, 20s, 40s, etc.

[0071] Step 1023, I a (t1), I a (t2), ...I a (t n ) as the protection threshold of the first threshold curve, and I b (t1), I b (t2), ...I b (t n This serves as the protection threshold for the second threshold curve.

[0072] Steps 1021 to 1023 above are obtained by analyzing the first threshold curve L. a Second threshold curve L b The current value at the corresponding time point is selected as the protection threshold. Appropriate current thresholds can be set for different time points to determine whether the current exceeds the safety limit.

[0073] In some instances of this application, step 102 above, which involves calculating the root mean square current value at each of the plurality of time points, includes:

[0074] Step 1024, based on each interval Δt after the battery has been working, each interval Δt is for each time point (t1, t2, ..., t... n Perform a root mean square current calculation, specifically including:

[0075] Step 10241, within a time interval Δt, for a time point t n At that time point t n If a current value is acquired at every time interval n′ during the reverse time, then N current values ​​are obtained, where N = t n / n′;

[0076] Step 10242: Calculate time point t according to the following root mean square formula. n The root mean square current value:

[0077]

[0078] And so on, calculate t1, t2, ..., t n-1 The root mean square current values ​​corresponding to the time points are I(t1), I(t2), ..., I(t) in sequence. n-1 ).

[0079] In step 1024 above, after selecting the protection threshold, the root mean square (RMS) current value is calculated for each time point. The RMS current value is an effective indicator for measuring current fluctuations; it comprehensively reflects the average value and the magnitude of current variation, helping to assess current stability.

[0080] The root mean square current value calculated at each time point in steps 10241 to 10242 can be compared with the corresponding protection threshold to determine and trigger corresponding protection measures, so as to ensure that the relay operates within a safe and stable range.

[0081] The following example illustrates this further.

[0082] For example, in the first threshold curve L a Second threshold curve L b Ten time points were selected from each of the above. Among them, the first threshold curve L a The 10 time points are as follows:

[0083] (500A, 2s), (450A, 5s), (380A, 10s), (320A, 20s), (310A, 40s), (300A, 80s), (250A, 120s), (200A, 200s), (170A, 400s), (150A, 800s);

[0084] Second threshold curve L b The 10 time points are as follows:

[0085] (700A, 2s), (630A, 5s), (580A, 10s), (500A, 20s), (450A, 40s), (380A, 80s), (330A, 120s), (240A, 200s), (200A, 400s), (180A, 800s).

[0086] If the root mean square (RMS) current is calculated by taking a value at every time interval Δt, then the Battery Management System (BMS) needs to calculate the RMS current value (IRMS) 2s, 5s, 10s, 20s, 40s, 80s, 120s, 200s, 400s, and 800s backwards from the same time point. This calculation is performed every time interval Δt. For example, at the 1000th second after the battery starts operating, assuming n′ = 1s, meaning a current value is obtained every 1s, the RMS current value for the 10 backward time intervals from the current time point is calculated as follows:

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098] Among them, IRMS 2 (40S) 20S This represents the root mean square current value within 20 seconds of the current time point 40 seconds prior.

[0099] It should be noted that the RMS current calculation for a long time period can be equivalently calculated by using the RMS current of an equally allocated time period, thereby reducing the data storage of the battery management system.

[0100] In some embodiments of this application, step 103 above, the step of controlling the reduction of current if any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, includes:

[0101] If I(t1)≥I a (t1), or I(t2)≥I a(t2), or..., or I(t) n )≥I a (t n If the current is reduced, the battery management system will control the reduction of the current.

[0102] Specifically, when controlling current in a battery management system, the current can be reduced to below the relay's rated current. For example, the current can be controlled at 50% of the rated current. If the relay's rated current is 250A, the current can be controlled at 125A or lower. By controlling the current below the relay's rated current, it ensures that the relay operates normally without exceeding its capacity range. For example, controlling the current at 50% of the rated current provides the relay with a certain capacity margin to ensure its reliability and lifespan; on the other hand, it reduces load and power consumption, improving the system's energy efficiency and stability.

[0103] In summary, this application uses threshold curves and root-mean-square (RMS) current values ​​to determine and trigger protection measures based on preset operating conditions and relay characteristics. Once the RMS current value exceeds the protection threshold corresponding to the threshold curve, the system's safe operation is protected by reducing the current or disconnecting the relay.

[0104] In addition to the current root mean square strategy provided above, in some other embodiments of this application, another strategy is also provided, namely, a relay temperature detection strategy. Please refer to [link / reference]. Figure 3 , Figure 3 This is a schematic diagram of a relay and battery management system provided in an embodiment of this application. A relay control method further includes:

[0105] Step 301: Obtain the real-time temperature T of the relay.

[0106] Specifically, a temperature sensor can be installed on the relay and connected to the battery management system so that the battery management system can detect the temperature T of the relay.

[0107] By installing a temperature sensor and connecting it to the battery management system (BMS), the relay's temperature information can be obtained in real time. The BMS can then use this temperature data to monitor the relay's operating temperature. Monitoring the relay's temperature is crucial for the BMS because relays typically generate heat during operation. Overheating can affect the relay's performance and lifespan, and may even lead to malfunction or damage. By connecting a temperature sensor and detecting the relay's temperature, the BMS can take timely protective measures based on temperature changes, ensuring the relay's safe operation and extending its lifespan.

[0108] Step 302, configure the temperature to be lower than the upper limit T of the relay's operating temperature. aThe first protection temperature threshold T1 and the value below the upper limit of the relay's safe temperature T b The second protection temperature threshold T2, where T b >T2>T a >T1.

[0109] If T≥T1, the current is reduced by controlling the battery management system.

[0110] If T ≥ T2, the relay is disconnected by the battery management system.

[0111] In other words, when the relay temperature T exceeds the set first protection temperature threshold T1, the battery management system will take measures to reduce the current flowing through the relay to prevent overheating and performance degradation. When the relay temperature T exceeds the set second protection temperature threshold T2, the battery management system will trigger a protection mechanism, causing the relay to disconnect to prevent overheating.

[0112] Therefore, the relay temperature detection strategy provided in this application allows the battery management system to take corresponding control measures based on the relay temperature by setting different protection temperature thresholds, so as to ensure that the relay operates within a safe operating temperature range.

[0113] It should be noted that the relay temperature detection strategy is based on the relay's own temperature change. A temperature sensor is installed on the relay to monitor its temperature, and a corresponding protection temperature threshold is set. When the relay temperature reaches or exceeds the set threshold, the battery management system will execute corresponding protection measures, such as reducing the current or disconnecting the relay, to prevent overheating or damage. The root-mean-square (RMS) thermal model strategy protects the relay based on the circuit's current conditions. Specifically, a protection threshold curve is determined based on the vehicle's current-time operating condition curve and the relay's operating current-time curve. Multiple time points are then selected on this curve as strategy threshold protection points. Subsequently, the RMS current is calculated using the battery management system's RMS current calculation model and compared with the set protection threshold. When the RMS current reaches or exceeds the set threshold, the battery management system will execute corresponding protection measures, such as reducing the current or disconnecting the relay.

[0114] The battery management system described in this application can simultaneously use a relay temperature detection strategy and a current root mean square thermal model strategy to comprehensively protect the safe operation of the relay and circuit system.

[0115] The control device for the relay provided in this application is described below. The control device for the relay described below can be referred to in correspondence with the control method for the relay described above.

[0116] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of the relay control device provided in this application. The relay control device 400 includes a threshold curve determination module 401, a root mean square current calculation module 402, and a control module 403.

[0117] For example, the threshold curve determination module 401 is used to:

[0118] Based on the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by the preset relay, a first threshold curve and a second threshold curve are determined, wherein at the same time point, the values ​​corresponding to the current-time operating condition curve, the operating current-time curve, the first threshold curve and the second threshold curve are in an increasing relationship.

[0119] For example, the root mean square current calculation module 402 is used for:

[0120] The current values ​​at multiple time points are selected from the first threshold curve and the second threshold curve respectively as protection thresholds, and the root mean square current value at each of the multiple time points is calculated respectively.

[0121] For example, the control module 403 is used to:

[0122] When any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, the current is reduced; and when any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point, the relay is disconnected.

[0123] Exemplarily, the device further includes a relay temperature control module, the relay temperature control module being used for:

[0124] Obtain the real-time temperature T of the relay;

[0125] Configured below the upper limit of the relay's operating temperature T a The first protection temperature threshold T1 and the value below the upper limit of the relay's safe temperature T b The second protection temperature threshold T2, where T b >T2>T a >T1;

[0126] If T≥T1, the current is reduced by controlling the battery management system.

[0127] If T ≥ T2, then the relay is disconnected by the battery management system.

[0128] For example, the threshold curve determination module 401 is also used for:

[0129] Select multiple corresponding time points on the current-time operating condition curve and the operating current-time curve respectively;

[0130] Based on each time point, the first threshold curve is determined at a preset first position of the distance between the current-time operating condition curve and the operating current-time curve, and the second threshold curve is determined at a preset second position of the distance between the current-time operating condition curve and the operating current-time curve.

[0131] At the same time point, the current value at the preset first position is less than the current value at the preset second position.

[0132] For example, the root mean square current calculation module 402 is also used for:

[0133] Select t1, t2, ..., t on the first threshold curve. n The current value at a given time point is denoted as I. a (t1), I a (t2), ...I a (t n ), where n is a positive integer;

[0134] Select t1, t2, ..., t from the second threshold curve that correspond to the first threshold curve. n The time points and their corresponding current values ​​are represented as Ib(t1) and I... b (t2), ...I b (t n );

[0135] Will I a (t1), I a (t2), ...I a (t n ) as the protection threshold of the first threshold curve, and I b (t1), Ib(t2), ...I b (t n () is used as the protection threshold for the second threshold curve.

[0136] For example, the root mean square current calculation module 402 is also used for:

[0137] Based on each interval Δt after the battery has been operating, each interval Δt is for each time point (t1, t2, ..., t... n Perform a root mean square current calculation, specifically including:

[0138] Within a time interval Δt, for a time point t n At that time point t nIf a current value is acquired at every time interval n′ during the reverse time, then N current values ​​are obtained, where N = t n / n′;

[0139] Calculate the root mean square current value at time point tn using the following root mean square formula:

[0140]

[0141] And so on, calculate t1, t2, ..., t n-1 The root mean square current values ​​corresponding to the time points are I(t1), I(t2), ..., I(t) in sequence. n-1 ).

[0142] For example, the control module 403 is also used to:

[0143] If I(t1)≥I a (t1), or I(t2)≥I a (t2), or..., or I(t) n )≥I a (t n If the current is reduced, the battery management system will control the reduction of the current.

[0144] For example, the control module 403 is also used to:

[0145] I(t1)≥I b (t1), or I(t2)≥I b (t2), or..., or I(t) n )≥I b (t n If the battery management system controls the relay to disconnect, then the relay will disconnect.

[0146] It should be noted that the control device for the relay provided in this application embodiment can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0147] In some embodiments of this application, this application also provides a battery management system, which is connected to a relay, and the battery management system executes a program to implement the steps of the relay control method described above.

[0148] The battery management system provided in this application embodiment can implement all the method steps implemented in the above method embodiment and achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0149] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for controlling a relay, characterized in that, The method includes: Based on the current-time operating condition curve provided by the vehicle and the operating current-time curve provided by a preset relay, multiple corresponding time points are selected on the current-time operating condition curve and the operating current-time curve, respectively. Based on each time point, a first threshold curve is determined at a preset first position of the distance between the current-time operating condition curve and the operating current-time curve, and a second threshold curve is determined at a preset second position of the distance between the current-time operating condition curve and the operating current-time curve. The first threshold curve is a current reduction protection curve, and the second threshold curve is a relay disconnection current protection curve. At the same time point, the values ​​of the current-time operating condition curve, the first threshold curve, the second threshold curve, and the operating current-time curve are in an increasing relationship. The current values ​​at multiple time points are selected from the first threshold curve and the second threshold curve respectively as protection thresholds, and the root mean square current value at each of the multiple time points is calculated respectively. If any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, the current is controlled to decrease; and if any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point, the relay is controlled to disconnect.

2. The relay control method according to claim 1, characterized in that, The method further includes: Obtain the real-time temperature T of the relay; Configure a first protection temperature threshold T1 that is lower than the upper limit of the relay's operating temperature Ta and a second protection temperature threshold T2 that is lower than the upper limit of the relay's safe temperature Tb, wherein Tb>T2>Ta>T1.

3. The relay control method according to claim 2, characterized in that, If T T1, on the other hand, controls the reduction of current through the battery management system; If T T2 then controls the relay to disconnect via the battery management system.

4. The relay control method according to claim 1, characterized in that, At the same time point, the current value at the preset first position is less than the current value at the preset second position.

5. The relay control method according to claim 1 or 4, characterized in that, The step of selecting current values ​​at multiple time points from the first threshold curve and the second threshold curve as protection thresholds includes: Select time points t1, t2, ..., tn on the first threshold curve, and the corresponding current values ​​are represented as Ia(t1), Ia(t2), ..., Ia(tn), where n is a positive integer; Select time points t1, t2, ..., tn corresponding to the first threshold curve in the second threshold curve, and the corresponding current values ​​are represented as Ib(t1), Ib(t2), ..., Ib(tn), where n is a positive integer; Ia(t1), Ia(t2), ..., Ia(tn) are used as the protection thresholds of the first threshold curve, and Ib(t1), Ib(t2), ..., Ib(tn) are used as the protection thresholds of the second threshold curve.

6. The relay control method according to claim 5, characterized in that, The step of calculating the root mean square current value at each of the plurality of time points includes: Based on each interval Δt after the battery has been operating, the root mean square current value is calculated once for each time point (t1, t2, ..., tn) at each interval Δt, specifically including: Within a time interval Δt, for a time point tn, within the backward time interval from that time point tn, each time interval... If one current value is obtained, then N current values ​​are obtained, among which... ; Calculate the root mean square current value at time point tn using the following root mean square formula: ； Similarly, the root mean square current values ​​corresponding to time points t1, t2, ..., tn-1 are calculated as I(t1), I(t2), ..., I(tn-1).

7. The relay control method according to claim 6, characterized in that, If any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, the step of controlling the reduction of current includes: If I(t1) Ia(t1), or I(t2) Ia(t2), or..., or I(tn). Ia(tn) is then controlled by the battery management system to reduce the current.

8. The relay control method according to claim 6, characterized in that, The step of controlling the relay to disconnect if any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point includes: I(t1) Ib(t1), or I(t2) Ib(t2), or..., or I(tn). Ib(tn) then controls the relay to disconnect via the battery management system.

9. A control device for a relay, characterized in that, The device includes: The threshold curve determination module is used to select multiple corresponding time points on the current-time operating condition curve and the operating current-time curve based on the current-time operating condition curve provided by the vehicle and the operating current-time curve based on a preset relay; based on each time point, a first threshold curve is determined at a preset first position of the distance between the current-time operating condition curve and the operating current-time curve, and a second threshold curve is determined at a preset second position of the distance between the current-time operating condition curve and the operating current-time curve, wherein the first threshold curve is a current reduction protection curve, the second threshold curve is a relay disconnection current protection curve, and at the same time point, the values ​​corresponding to the current-time operating condition curve, the operating current-time curve, the first threshold curve, and the second threshold curve are in an increasing relationship; The root mean square current calculation module is used to select the current values ​​at multiple time points from the first threshold curve and the second threshold curve as protection thresholds, and to calculate the root mean square current value at each of the multiple time points. The control module is used to control the current to decrease when any root mean square current value is greater than or equal to the protection threshold of the first threshold curve at the same time point, and to control the relay to disconnect when any root mean square current value is greater than or equal to the protection threshold of the second threshold curve at the same time point.

10. A battery management system, characterized in that, The battery management system is connected to a relay, and when the battery management system executes a program, it implements the steps of the relay control method as described in any one of claims 1 to 8.

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