Vehicle low-voltage storage battery model selection method

Abstract

The invention discloses a vehicle low-voltage storage battery model selection method, and belongs to the technical field of vehicle low-voltage storage batteries. According to the scheme, the rated capacity of the storage battery is calculated by estimating the vehicle sleep current, the power-on and power-off power consumption, the number of storage days and the false wake-up power consumption in combination with the initial battery capacity percentage of the storage battery, the battery capacity percentage after storage and the unit self-loss rate of the storage battery, and the storage battery meeting the requirement is selected according to the calculated rated capacity. And then performing a cold start test by using the storage battery, and judging whether the cold start current, the cold start stable discharge duration and the cold start output voltage of the storage battery meet the test requirements or not. According to the scheme, storage battery type selection is carried out by comprehensively considering multiple factors, storage battery capacity selection is more accurate, complex working conditions such as cold start can be met, the storage battery type selection precision is improved, and then the safety of the vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle low-voltage battery technology, and in particular to a method for selecting vehicle low-voltage batteries. Background Technology

[0002] like Figure 1 As shown, the low-voltage battery, as an important component of the vehicle's power supply, together with the alternator, forms the vehicle's power system. The common main functions of the low-voltage battery are as follows:

[0003] (1) When the vehicle starts, the low-voltage battery provides a large instantaneous current to the starter motor to ensure that the starter motor can start smoothly within the required range;

[0004] (2) When the vehicle is off, it provides power to the electrical components so that they can work normally, and at the same time ensures that the vehicle can be started smoothly after being left for a period of time.

[0005] (3) When the generator output is less than the vehicle's power demand, it supplies power to the vehicle's electrical equipment together with the generator.

[0006] (4) When the generator output exceeds the vehicle's power demand, the remaining electrical energy of the generator is converted into chemical energy and stored.

[0007] (5) It is equivalent to a large capacitor, which can absorb instantaneous overvoltages in the circuit and maintain the stability of the voltage of the automotive electrical system.

[0008] With the development of the automotive industry, the demands of vehicles for low-voltage batteries are becoming increasingly complex. Different vehicle models and application scenarios also have different requirements for low-voltage batteries. To ensure the normal operation of vehicles under various conditions such as when parked and during cold starts, the selection of batteries is particularly important. However, traditional battery selection methods often only consider the battery's starting current and capacity, and do not take into account special circumstances such as power consumption during power-on / off cycles and accidental wake-ups. This may result in the selection of an undersized battery, leading to severe discharge during operation and affecting the vehicle's ability to start on subsequent runs. Furthermore, traditional battery selection does not consider extreme weather conditions, which may prevent the vehicle from starting in extreme weather conditions. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a method for selecting low-voltage batteries for vehicles, which addresses the above-mentioned deficiencies of the prior art and makes the selection of vehicle batteries more accurate.

[0010] To achieve the above objectives, the present invention provides a method for selecting a low-voltage battery for a vehicle, the method comprising the following steps:

[0011] Step S1: Estimate vehicle sleep current;

[0012] Step S2: Estimate the power consumption when the vehicle is going up or down;

[0013] Step S3: Estimate the number of days the vehicle will be parked;

[0014] Step S4: Estimate the power consumption of the vehicle if it is falsely woken up;

[0015] Step S5: Calculate the battery capacity using the following formula, and select a battery based on the calculated battery capacity:

[0016]

[0017] Where C20 is the 20-hour rated capacity of the battery, C sleep C represents the power consumption when the vehicle is started and stopped. awaken Power consumption due to vehicle false wake-up, I QC The current is the vehicle's sleep current, T is the number of days the vehicle has been idle, and SOC is the state of charge. start SOC (State of Charge) represents the initial battery capacity percentage. park A represents the percentage of battery capacity after placement, and A represents the battery's unit self-loss rate.

[0018] Step S6: Perform a cold start test using the battery selected in step S5. Determine whether the cold start current, cold start stable discharge duration, and cold start output voltage of the battery all meet the test requirements through the cold start test.

[0019] Preferably, in step S1, the method for estimating the vehicle sleep current is as follows: during the pre-research phase, based on the vehicle configuration and functional requirements, the types and quantities of ECU modules involved in the project are determined, the sleep current of each ECU module in the vehicle project is estimated according to the network management strategy, and the total sleep current of each ECU module is calculated.

[0020] Preferably, in step S2, the method for estimating the vehicle's power consumption during power-off is as follows: based on the sleep strategy of all ECUs in the vehicle, a schematic diagram of the vehicle's current change curve after the engine is turned off is plotted; based on the schematic diagram, the time from engine shutdown to complete vehicle sleep and the average current during power-off are estimated; and the vehicle's power consumption during power-off is calculated according to the following formula:

[0021]

[0022] Among them, t a Indicates the time from when the vehicle is turned off until it is completely idle, in seconds. a This represents the average current during the power-off period.

[0023] Preferably, in step S2, the method for estimating the power consumption of the vehicle when it is powered on is to use the estimated power consumption of the vehicle when it is powered off as the estimated power consumption of the vehicle when it is powered on.

[0024] Preferably, in step S3, the method for estimating the number of days the vehicle will be placed is: to estimate the number of days the vehicle will be placed based on the vehicle configuration and cost budget.

[0025] Preferably, in step S4, the method for estimating the power consumption of the vehicle during false wake-ups is as follows: based on the vehicle configuration, the estimated frequency of false wake-ups, the average duration of false wake-ups, and the processor operating current after each wake-up, the power consumption during false wake-ups is calculated according to the following formula:

[0026]

[0027] Where N represents the number of times the device is falsely awakened in a day, and t b Indicates the average duration of false wake-ups, in seconds. b The current represents the processor's operating current after wake-up, and T represents the estimated number of days the vehicle will be parked in step S3, in days.

[0028] Preferably, in step S6, the cold start test is conducted in a real vehicle environment.

[0029] Preferably, in step S6, the cold start test is performed based on a simulation environment.

[0030] Preferably, in step S6, the cold start stable discharge duration is greater than 30 seconds, and the cold start output voltage of the battery is not less than 7.2V.

[0031] Preferably, the method further includes:

[0032] Step S7: Select the battery manufacturing process based on the vehicle model.

[0033] This invention offers the following advantages: By estimating vehicle sleep current, power consumption during startup and shutdown, storage days, and power consumption during false wake-ups, and combining this with the initial battery capacity percentage, the battery capacity percentage after storage, and the battery's unit self-loss rate, the invention calculates the rated capacity of the battery. Based on the calculated rated capacity, a battery that meets the requirements is selected. Then, a cold start test is performed using this battery to determine whether the cold start current, cold start stable discharge duration, and cold start output voltage all meet the test requirements. This invention comprehensively considers multiple factors in battery selection, resulting in more accurate battery capacity selection and the ability to meet complex operating conditions such as cold starts. This improves the accuracy of battery selection and, consequently, enhances vehicle safety. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0035] Figure 1 This is a schematic diagram of the vehicle's power system.

[0036] Figure 2 This is a schematic diagram illustrating the steps of a vehicle low-voltage battery selection method provided in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the vehicle current change curve during the power consumption process after vehicle power-off, provided as an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The general idea of ​​this invention is to comprehensively consider the power consumption of vehicle power-on and power-off, power consumption of vehicle false wake-up, power consumption during sleep, and battery self-consumption to calculate the capacity of the vehicle's low-voltage battery, and then verify whether the selected battery meets the cold start requirements through a cold start test.

[0040] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. It should be understood that the embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0041] Selecting a low-voltage battery for a vehicle is a complex process that requires consideration of multiple factors, including sleep current, initial battery capacity, battery capacity after storage, daily self-discharge of the battery, and the number of days the vehicle is stored. It is necessary to comprehensively analyze the vehicle's operating status under various scenarios and establish a more comprehensive method for selecting low-voltage batteries for vehicles. This will help find a low-voltage battery model that meets performance requirements while having lower weight, size, and cost, thus providing strong support for the safe, reliable, and efficient operation of the vehicle.

[0042] like Figure 2 As shown in the figure, this embodiment of the invention provides a method for selecting a low-voltage battery for a vehicle, the method comprising the following steps:

[0043] Step S1: Estimate the vehicle's sleep current.

[0044] Sleep current is the current consumed by the vehicle controller in sleep mode. Although the current is relatively small, it still causes the battery to lose charge while the vehicle is idle. To ensure that the vehicle can still start normally after a long period of inactivity, the low-voltage battery charge should generally not be lower than 60% after 40 to 50 days of inactivity. This requires precise control and management of the sleep current.

[0045] Common ECU (Electronic Control Unit) network management strategies include: CAN (Controller Area Network) bus direct network management, CAN bus indirect network management, and LIN (Local Interconnect Network) bus network management. Different network management strategies correspond to different ECU sleep strategies, and the sleep current of the ECU varies under different ECU sleep strategies.

[0046] During the preliminary research phase, based on vehicle configuration and functional requirements, the types and quantities of ECU modules involved in the project are determined. The sleep current of each ECU module in the vehicle project is estimated according to the network management strategy, and the total sleep current of each ECU module is calculated.

[0047] Step S2: Estimate the power consumption when the vehicle goes up and down.

[0048] The method for estimating the vehicle's power consumption during power-off is as follows: Based on the sleep strategy of all ECUs in the vehicle, a schematic diagram of the vehicle's current change after the engine is turned off is plotted. Based on the schematic diagram, the time from engine shutdown to complete vehicle sleep and the average current during the power-off period are estimated. The vehicle's power consumption during power-off is then calculated using the following formula:

[0049]

[0050] Among them, t a Indicates the time from when the vehicle is turned off until it is completely idle, in seconds. a This represents the average current during the power-off period.

[0051] like Figure 3 The figure shows the vehicle current change curve after the engine is turned off, according to an embodiment of the present invention. It is assumed that the driver leaves the vehicle and locks it 90 seconds after the engine is turned off. The current t is estimated from the figure. a =300 seconds, I a =4A, Csleep=300s×4A / 3600=0.33Ah.

[0052] The method for estimating the power consumption of a vehicle when it is powered on is as follows: the estimated power consumption of the vehicle when it is powered off is used as the estimated power consumption when it is powered on.

[0053] Step S3: Estimate the number of days the vehicle will be parked.

[0054] The method for estimating the number of days a vehicle will be placed is as follows: the number of days a vehicle will be placed is estimated based on the vehicle configuration and cost budget.

[0055] Vehicle storage days refers to the estimated number of days a vehicle will be left unused. In practice, the estimated storage days are determined based on the specific vehicle configuration and cost budget. The longer the vehicle is to be stored, the larger the required low-voltage battery capacity and the higher the cost.

[0056] Step S4: Estimate the power consumption of the vehicle if it is falsely woken up.

[0057] The power consumption due to false wake-up of the vehicle refers to the total power consumed by the vehicle due to false wake-up within the estimated number of days the vehicle is parked.

[0058] Environmental factors and external interference can cause false wake-ups of certain components. For example, considering the requirements of digital key functionality, the PEPS (Passive Entry Passive Start) controller is primarily responsible for receiving signals from the digital key and communicating with the vehicle to enable keyless entry and start. However, when interference signals of the same frequency as the PEPS system exist in the environment, these signals may interfere with the normal operation of the PEPS controller, causing it to misjudge the signal source and trigger a false wake-up.

[0059] Accidental wake-up can cause unnecessary power consumption of the vehicle's low-voltage battery, and the power consumption during this process should also be taken into account when selecting a low-voltage battery.

[0060] The method for estimating the power consumption of vehicle false wake-ups is as follows: based on the vehicle configuration, the estimated frequency of false wake-ups, the average duration of false wake-ups, and the processor operating current after each wake-up, the power consumption of false wake-ups is calculated according to the following formula:

[0061]

[0062] Where N represents the number of times the device is falsely awakened in a day, and t b Indicates the average duration of false wake-ups, in seconds. b The current represents the processor's operating current after wake-up, and T represents the estimated number of days the vehicle will be parked in step S3, in days.

[0063] The types and number of components that may be accidentally woken up may vary depending on the vehicle configuration. It is necessary to analyze the cause, frequency, duration, and current consumption of accidental wake-up based on the vehicle configuration.

[0064] For example, assuming an average of one false wake-up per hour, with each wake-up requiring a controller current of 150mA and a return to sleep after 8 seconds, the total power consumption of the vehicle after being idle for T days would be:

[0065] Cawaken=150mA×8×24×T / 3600mAh.

[0066] Step S5: Calculate the battery capacity using the following formula, and select a battery based on the calculated battery capacity:

[0067]

[0068] Wherein, C20 is the 20-hour rated capacity of the battery, C sleep C represents the power consumption when the vehicle is started and stopped. awaken Power consumption due to vehicle false wake-up, I QC The current is the vehicle's sleep current, T is the number of days the vehicle has been idle, and SOC is the state of charge. start SOC (State of Charge) represents the initial battery capacity percentage. park A represents the percentage of battery capacity after placement, and A is the battery's unit self-loss rate, i.e., the battery's daily self-loss rate.

[0069] SOCstart indicates the percentage of battery capacity at the time of manufacture relative to the battery's rated capacity, typically between 85% and 95%. SOCpark indicates the percentage of battery capacity relative to the rated capacity after a designed number of storage days. After storage, the battery capacity should meet cold start requirements, typically requiring no less than 60% in the industry. A represents the battery's unit self-loss rate, based on the loss during the required number of storage days, reflecting the utilization rate of the battery's SOC during the storage period.

[0070] The formula for calculating the rated capacity of low-voltage batteries in Chinese patent document CN109747438B is as follows:

[0071]

[0072] Compared to Formula 3, it does not consider power consumption during power-on / off cycles and false wake-ups. In addition, the calculation of the unit self-loss rate of the battery is different, treating the unit self-loss rate of the battery as the self-loss rate over the battery's lifespan.

[0073] The solution of this invention takes into account power consumption during power-on and power-off cycles, false wake-up, and battery self-consumption when calculating the rated capacity of the low-voltage battery.

[0074] The following is a comparison of data for several options:

[0075] Option 1: Based on the solution of this invention, without considering power consumption during power-on / off or false wake-up, the calculation is performed according to the following formula.

[0076]

[0077] Solution 2: The solution of the present invention, namely Formula 3.

[0078] Scheme 3: The calculation scheme in Chinese patent document CN109747438B, i.e., the scheme of formula 4.

[0079] Assuming the vehicle is parked for 40 days (T), the battery's unit self-loss rate is 1‰, the initial battery capacity percentage (SOCstart) is 90%, the battery capacity percentage (SOCpark) after parking is 60%, the power consumption for powering on and off is 0.33Ah, and the power consumption for false wake-up is 150mA × 8 × 24 × T / 3600mAh = 0.32Ah. The rated battery capacity calculated for the three scenarios with sleep currents of 10mA, 20mA, and 30mA is shown in Table 1 below.

[0080] Table 1. Comparison of Rated Capacity Data of Low-Voltage Batteries Calculated for Different Sleep Currents

[0081]

[0082] As shown in Table 1, the solution of this invention, by considering power consumption during power-on / off and power consumption during false wake-up, calculates a more accurate rated battery capacity compared to solution 1. Solution 3, due to differences in its method for calculating battery self-discharge utilization, results in an overestimation of the rated battery capacity. Selecting a battery using the method of solution 3 would lead to an over-selection of capacity, resulting in wasted costs.

[0083] Assuming the vehicle's sleep current is 20mA, the battery's unit self-loss rate is 1‰, the initial battery capacity percentage SOCstart is 90%, the battery capacity percentage SOCpark after storage is 60%, the power consumption for powering on and off is 0.33Ah, and the power consumption for false wake-up is 150mA × 8 × 24 × T / 3600mAh = 0.32Ah. The rated battery capacity calculated for the three scenarios (T) when the vehicle is stored for 40 days, 45 days, and 50 days respectively is shown in Table 2 below.

[0084] Table 2 Comparison of Rated Capacity Data of Low-Voltage Batteries Calculated for Different Placement Days Table 2 Comparison of Rated Capacity Data of Low-Voltage Batteries for Different Schemes

[0085]

[0086] As shown in Table 2, the selection error of Scheme 3 increases with the number of days the device is left idle, leading to unnecessary cost waste. Scheme 2, on the other hand, takes into account scenarios such as accidental wake-up and power-off hibernation, and provides a more accurate rated capacity result.

[0087] Step S6: Perform a cold start test using the battery selected in step S5. Determine whether the cold start current, cold start stable discharge duration, and cold start output voltage of the battery all meet the test requirements through the cold start test.

[0088] Through steps S1-S5, the rated capacitance of the low-voltage battery is calculated, and the battery is selected based on the calculated rated capacity. However, in addition to the rated capacity, it is also necessary to consider whether the low-voltage battery can meet the vehicle's starting requirements. Vehicle starting is divided into cold start and normal temperature start, depending on the temperature at the time of starting. Cold start refers to starting under extreme low temperature conditions. If the low-voltage battery can meet the cold start requirements, it will certainly meet the normal temperature start requirements. Therefore, the present invention, after selecting a low-voltage battery that meets the rated capacity, uses a cold start test to determine whether the low-voltage battery meets the starting requirements.

[0089] The cold start test is conducted in either a real vehicle environment or a simulation environment. In practical applications, either a real vehicle test environment or a simulation test environment can be set up for the cold start test depending on the test conditions.

[0090] Battery cold-start capability refers to the battery's ability to start the engine in low-temperature environments. In cold climates, the battery needs to provide sufficient power to the vehicle's starting, ignition, and electronic fuel injection systems to ensure the engine can start smoothly. The quality of cold-start capability primarily depends on the battery's CCA (Cold Cranking Amps) value, i.e., the cold-start current. A higher CCA value indicates a stronger starting capability at low temperatures.

[0091] Under extreme low-temperature conditions, the performance of low-voltage batteries is significantly affected, and their discharge capacity decreases markedly. This is mainly because low temperatures slow down the chemical reaction rate inside the battery, reduce the fluidity of the electrolyte, and increase the internal resistance of the battery. Therefore, the following factors need to be considered when selecting low-voltage batteries:

[0092] (1) Discharge current of the battery at -35℃:

[0093] Under extreme low temperatures, battery performance is affected, and its discharge capacity decreases. Therefore, to ensure a vehicle can start normally at -35°C, the battery's discharge current must be greater than the starting current required by the starter motor. This typically requires the battery to have excellent low-temperature starting performance, meaning the cold start current should be large enough to ensure the engine can start quickly.

[0094] (2) Duration of battery discharge current:

[0095] Starting a vehicle in low temperatures can take longer, so the battery discharge current must last longer than the vehicle's cold-start time. Typically, this starting time is set at 30 seconds, meaning the battery needs to provide a stable current during this period to ensure the engine starts successfully.

[0096] By conducting a cold start test on the battery and analyzing the starting time, starting voltage, and starting current data, it can be determined whether the battery meets the cold start requirements. This ensures the vehicle's normal starting performance in low-temperature environments, improving the overall reliability and safety of the vehicle. If the starting time is too long or the starting current is too low, further inspection of the battery's performance may be necessary, or battery replacement may be considered.

[0097] The following explanation uses a cold start test as an example. First, based on the characteristic curve of a certain vehicle's starter motor at -35℃, the low-temperature starting current is determined to be no less than 350A. In addition, for safety reasons, the starting duration should be greater than 30 seconds, and the battery output voltage should not be lower than 7.2V during the cold start. The experimental data for the cold start test are shown in Table 3.

[0098] Table 3 Cold Start Test Data

[0099]

[0100] Among them, "battery driving voltage" corresponds to the battery output voltage, "battery driving current" corresponds to the battery starting current, and "driving time" corresponds to the starting time. In the three sets of starting data in Table 3, the actual starting time is less than 30 seconds, the battery output voltage is higher than 7.2V, and the starting current is higher than 350A, indicating that the selected low-voltage battery meets the cold start requirements.

[0101] The requirement that the cold start stable discharge duration be greater than 30 seconds and the cold start output voltage of the battery be no less than 7.2V are universal cold start test requirements for all vehicle models. The cold start current needs to be adapted according to the -35℃ characteristic curve of the starter motor of each vehicle model.

[0102] The vehicle low-voltage battery selection method provided in this embodiment of the invention further includes:

[0103] Step S7: Select the battery manufacturing process based on the vehicle model.

[0104] Currently, there are various types of batteries on the market made using different technologies, including AGM (Absorbent Glass Mat) batteries, EFB (Enhanced Flooded Battery) batteries, and ordinary lead-acid batteries. Batteries manufactured using different technologies have different characteristics. The main feature of AGM batteries is their use of special glass fiber separators. These separators have excellent liquid absorption and retention capabilities, uniformly absorbing and locking the electrolyte within the separator, unlike traditional lead-acid batteries where the electrolyte flows freely. EFB batteries are an improved version of lead-acid batteries, designed for use in modern automotive start-stop systems and other applications requiring frequent charge-discharge cycles. AGM batteries are suitable for high-end and luxury vehicles with frequent start-stop cycles, EFB batteries are suitable for hybrid vehicles and vehicles requiring frequent start-stop cycles, while ordinary lead-acid batteries are suitable for cost-sensitive vehicles and applications with lower performance requirements.

[0105] Therefore, it is also necessary to select the battery technology based on the vehicle model and cost to achieve the best matching effect. For example, for intelligent start-stop models, AGM batteries or EFB batteries that support frequent start-stop should be selected.

[0106] In addition, factors such as the size and weight of the low-voltage battery are also very important factors in the selection of the vehicle's low-voltage battery. When other parameters are similar, the size and weight parameters of the low-voltage battery can be combined to select a more suitable low-voltage battery product.

[0107] This invention offers the following advantages: By estimating vehicle sleep current, power consumption during startup and shutdown, storage days, and power consumption during false wake-ups, and combining this with the initial battery capacity percentage, the battery capacity percentage after storage, and the battery's unit self-loss rate, the invention calculates the rated capacity of the battery. Based on the calculated rated capacity, a battery that meets the requirements is selected. Then, a cold start test is performed using this battery to determine whether the cold start current, cold start stable discharge duration, and cold start output voltage all meet the test requirements. This invention comprehensively considers multiple factors in battery selection, resulting in more accurate battery capacity selection and the ability to meet complex operating conditions such as cold starts. This improves the accuracy of battery selection and, consequently, enhances vehicle safety.

[0108] The above are merely specific embodiments of the present invention and should not be construed as limiting the scope of the present invention. Equivalent variations made by those skilled in the art based on this invention, as well as changes well-known to those skilled in the art, should still fall within the scope of the present invention.

Claims

1. A method of selecting a low-voltage storage battery for a vehicle, characterized by, The method includes the following steps: Step S1: Estimate vehicle sleep current; Step S2: Estimate the power consumption when the vehicle is going up or down; Step S3: Estimate the number of days the vehicle will be parked; Step S4: Estimate the power consumption of the vehicle if it is falsely woken up; Step S5: Calculate the battery capacity using the following formula, and select a battery based on the calculated battery capacity: where C20 is the battery 20-hour rated capacity, C sleep is the vehicle up and down power consumption, C awaken is the vehicle false wake-up power consumption, I QC is the vehicle sleep current, T is the number of days the vehicle is placed, SOC start is the initial battery capacity percentage, SOC park is the battery capacity percentage after placement, A is the unit self-loss rate of the battery; Step S6: Perform a cold start test using the battery selected in step S5. Determine whether the cold start current, cold start stable discharge duration, and cold start output voltage of the battery all meet the test requirements through the cold start test.

2. The vehicle low-voltage battery selection method according to claim 1, characterized by, In step S1, the method for estimating the vehicle sleep current is as follows: during the pre-research phase, based on the vehicle configuration and functional requirements, the types and quantities of ECU modules involved in the project are determined, the sleep current of each ECU module in the vehicle project is estimated according to the network management strategy, and the total sleep current of each ECU module is calculated.

3. The vehicle low-voltage battery selection method according to claim 1, characterized by, In step S2, the method for estimating the vehicle's power consumption during power-off is as follows: Based on the sleep strategy of all ECUs in the vehicle, a schematic diagram of the vehicle's current change curve after the engine is turned off is plotted. Based on the schematic diagram, the time from engine shutdown to complete vehicle sleep and the average current during power-off are estimated. The vehicle's power consumption during power-off is then calculated using the following formula: where t a represents the time from the vehicle being turned off to the vehicle being completely asleep, in seconds, I a represents the average value of the current during the power down period.

4. The vehicle low-voltage battery selection method according to claim 3, characterized by, In step S2, the method for estimating the power consumption of the vehicle when it is powered on is as follows: the estimated power consumption of the vehicle when it is powered off is used as the estimated power consumption of the vehicle when it is powered on.

5. The vehicle low-voltage battery selection method according to claim 1, characterized by, In step S3, the method for estimating the number of days the vehicle will be placed is as follows: estimate the number of days the vehicle will be placed based on the vehicle configuration and cost budget.

6. The vehicle low-voltage battery selection method according to claim 1, characterized by, In step S4, the method for estimating the power consumption of the vehicle during false wake-ups is as follows: based on the vehicle configuration, the estimated frequency of false wake-ups, the average duration of false wake-ups, and the processor operating current after each wake-up, the power consumption during false wake-ups is calculated according to the following formula: where N represents the number of times of being falsely woken up in a day, t b represents the average length of false wake-up, in seconds, I b represents the processor working current after wake-up, and T represents the estimated vehicle placement days in step S3, in days.

7. The vehicle low-voltage battery selection method according to claim 1, characterized by, In step S6, the cold start test is conducted in a real vehicle environment.

8. The method for selecting a low-voltage battery for a vehicle according to claim 1, characterized in that, In step S6, the cold start test is performed based on a simulation environment.

9. The method for selecting a low-voltage battery for a vehicle according to claim 1, characterized in that, In step S6, the duration of the cold start stable discharge is greater than 30 seconds, and the cold start output voltage of the battery is not lower than 7.2V.

10. The method for selecting a low-voltage battery for a vehicle according to claim 1, characterized in that, The method further includes: Step S7: Select the battery manufacturing process based on the vehicle model.

Images