Method for determining DC charging current, device, and vehicle

Abstract

The present invention provides a method, apparatus, and vehicle for determining a DC charging current, and relates to the field of vehicle control. The method comprises the steps of: determining a first charging current according to a battery temperature; determining a second charging current according to a battery cell voltage; comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting to form a third charging current; looking up a table of maximum temperature and maximum elevator voltage according to the battery temperature to obtain a fourth charging current; comparing the magnitudes of the third charging current and the fourth charging current, taking the smaller value, and adding it to the current consumption of a high-voltage accessory to obtain a DC charging current required for battery charging. The present invention not only satisfies the requirements for a rapid charging current but also has high practicality because the charging current remains constant without exceeding the upper limit of the charging current based on battery temperature and cell voltage factors, thereby minimizing the impact of current rapid charging on battery life and performance.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims priority to a Chinese patent application filed with the Chinese Patent Office on October 9, 2020, with application number 202011074538.9 and application title “Method, apparatus and vehicle for determining DC charging current”, the entire contents of said application are incorporated by reference into this application.

[0003] The present invention relates to the field of vehicle control, and in particular to a method, apparatus, and vehicle for determining a DC charging current. Background Technology

[0004] With the increasing demand for eco-friendly vehicles, new energy vehicles are becoming more popular, and electric vehicles, in particular, which use batteries as a driving energy source, are gaining popularity among the public. However, along with the popularization of electric vehicles, the associated problems are also increasing, and solving these problems is becoming a severe challenge for current new energy vehicles.

[0005] Among the many problems, insufficient charging capacity and long charging times are particularly significant, and to reduce charging time, rapid charging, or DC charging, is emerging.

[0006] However, compared to AC charging, rapid charging differs significantly in its current setting, and the magnitude of the rapid charging current must be determined by considering various factors. Generally, based on the requirement to reduce charging time, the rapid charging current varies linearly and has a large value; however, since a linearly changing and large current significantly affects battery life and performance, finding a way to minimize the impact on battery life and performance while shortening charging time is an issue that the industry must urgently resolve. The problem to be solved

[0007] The present invention provides a method, apparatus, and vehicle for determining a DC charging current that can satisfy the requirements for a rapid charging current while minimizing the impact on battery life and performance. means of solving the problem

[0008] To solve the above technical problem, a first aspect of an embodiment of the present invention provides a method for determining a direct current charging current, said method,

[0009] A step of determining a first charging current as an upper limit of the allowable charging current at the current battery temperature;

[0010] A step of determining a second charging current as the upper limit of the allowable charging current at the current cell voltage of the battery;

[0011] A step of comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting to form a third charging current;

[0012] A step of obtaining a fourth charging current as an upper limit of the charging current allowed at the battery current temperature queried from the highest elevator voltmeter stored in a table form corresponding to the highest battery temperature; and,

[0013] A step of comparing the magnitudes of the third charging current and the fourth charging current, taking the smaller value, and adding it to the consumption current of the high-voltage accessory to obtain the DC charging current required for battery charging;

[0014] It includes the step of transmitting the above DC charging current to a charging file.

[0015] Alternatively, prior to the step of determining the first charging current according to the battery temperature, the method comprises:

[0016] Step of setting multiple temperature ranges according to the initial battery temperature;

[0017] The method further includes the step of setting a first charging current corresponding to each temperature range; and

[0018] Here, for each temperature interval lower than a preset temperature threshold, when the charging current rises above a preset first current value corresponding to the lowest battery temperature during the charging period, the first charging current is changed to a fifth charging current of the first current value; and when the charging current falls below a preset second current value corresponding to the lowest battery temperature during the charging period, the first charging current is changed to a sixth charging current of the second current value;

[0019] Here, for each temperature interval higher than a preset temperature threshold, when the charging current rises above a preset third current value corresponding to the battery's maximum temperature during the charging period, the first charging current is changed to a seventh charging current of the third current value; and when the charging current falls below a preset fourth current value corresponding to the battery's maximum temperature during the charging period, the first charging current is changed to an eighth charging current of the fourth current value.

[0020] Alternatively, prior to the step of determining a second charging current according to the cell voltage of the battery, the method comprises:

[0021] Step of setting multiple voltage ranges according to the maximum cell voltage of the battery;

[0022] The method further includes the step of setting a second charging current corresponding to each voltage interval;

[0023] Here, if the charging voltage during the charging period is lower than a preset first voltage value corresponding to the battery's highest cell voltage, the second charging current is changed to a ninth charging current of the first voltage value;

[0024] During the charging period, if the charging voltage is higher than the preset first voltage value corresponding to the battery's maximum cell voltage and simultaneously lower than the preset second voltage value, the second charging current is changed to the tenth charging current of the second voltage value.

[0025] Alternatively, prior to the step of comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting to form a third charging current, the method comprises:

[0026] A step of comparing the magnitudes of the first charging current and the second charging current and taking the smaller value;

[0027] When the value of the first charging current is small, the step of forming the third charging current with the difference between the value of the first charging current and the correction value;

[0028] If the value of the second charging current is small, the method includes the step of forming the third charging current with the difference between the value of the second charging current and the correction value.

[0029] Alternatively, the above method is,

[0030] A step of setting an initial temperature range, a special temperature range, and an end temperature range according to the initial battery temperature;

[0031] The method further includes the step of setting a first charging current corresponding to each of the initial temperature range, the special temperature range, and the termination temperature range.

[0032] Herein, within the initial temperature range, if the charging current is higher than a preset fifth current value corresponding to the lowest battery temperature, the first charging current is determined as the eleventh charging current of the fifth current value; if the charging current is lower than a preset fifth current value corresponding to the lowest battery temperature, the first charging current is changed to zero;

[0033] Within the above special temperature range, if the charging current is higher than a preset sixth current value corresponding to the highest temperature of the battery, the first charging current is changed to a 12th charging current of the sixth current value; if the charging current is lower than a preset seventh current value corresponding to the lowest temperature of the battery, the first charging current is changed to a 13th charging current of the seventh current value;

[0034] Within the above termination temperature range, if the charging current is lower than the eighth current value that is preset corresponding to the maximum temperature of the battery, the first charging current is determined as the 14th charging current of the eighth current value; if the charging current is higher than the eighth current value that is preset corresponding to the maximum temperature of the battery, the first charging current is changed to 0.

[0035] Alternatively, the above method is,

[0036] The method further includes the step of changing the second charging current to 0 when the maximum cell voltage of the battery is higher than a preset voltage threshold.

[0037] A second aspect of an embodiment of the present invention provides a DC charging current determining device, said device, said device

[0038] A first determination module for determining a first charging current as an upper limit of the charging current allowed at the current battery temperature;

[0039] A second determination module for determining a second charging current as an upper limit of the charging current allowed at the current cell voltage of the battery;

[0040] A comparison and correction module for forming a third charging current by comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting;

[0041] A table lookup module for obtaining a fourth charging current as the upper limit of the charging current allowed at the battery current temperature looked up from the highest elevator voltmeter stored in a table form corresponding to the highest battery temperature;

[0042] It includes a charging current determination module for determining the DC charging current required for battery charging by comparing the magnitudes of the third charging current and the fourth charging current, taking the smaller value, and adding it to the consumption current of the high-voltage accessory.

[0043] Alternatively, the above device,

[0044] Temperature range setting module for setting multiple temperature ranges according to the initial battery temperature;

[0045] It further includes a temperature range current setting module for setting a first charging current corresponding to each temperature range, and

[0046] Here, for each temperature interval lower than a preset temperature threshold, when the charging current rises above a preset first current value corresponding to the lowest battery temperature during the charging period, the first charging current is changed to a fifth charging current of the first current value; and when the charging current falls below a preset second current value corresponding to the lowest battery temperature during the charging period, the first charging current is changed to a sixth charging current of the second current value;

[0047] Here, for each temperature interval higher than a preset temperature threshold, when the charging current rises above a preset third current value corresponding to the battery's maximum temperature during the charging period, the first charging current is changed to a seventh charging current of the third current value; and when the charging current falls below a preset fourth current value corresponding to the battery's maximum temperature during the charging period, the first charging current is changed to an eighth charging current of the fourth current value.

[0048] Alternatively, the above device,

[0049] Voltage range setting module for setting multiple voltage ranges according to the maximum cell voltage of the battery;

[0050] It further includes a voltage range current setting module for setting a second charging current corresponding to each voltage range, and

[0051] Here, if the charging voltage during the charging period is lower than a preset first voltage value corresponding to the battery's highest cell voltage, the second charging current is changed to a ninth charging current of the first voltage value;

[0052] During the charging period, if the charging voltage is higher than the preset first voltage value corresponding to the battery's maximum cell voltage and simultaneously lower than the preset second voltage value, the second charging current is changed to the tenth charging current of the second voltage value.

[0053] Alternatively, the above comparison and correction module is,

[0054] A comparison unit for comparing the magnitudes of the first charging current and the second charging current and taking the smaller value;

[0055] When the value of the first charging current is small, the third charging current is formed by the difference between the value of the first charging current and the correction value, and

[0056] Additionally, when the value of the second charging current is small, it includes a correction unit for forming the third charging current with the difference between the value of the second charging current and the correction value.

[0057] Alternatively, the temperature range setting module also sets an initial temperature range, a special temperature range, and an end temperature range according to the battery initial temperature;

[0058] The temperature range current setting module also sets a first charging current corresponding to the initial temperature range, the special temperature range, and the end temperature range, respectively;

[0059] Herein, within the initial temperature range, if the charging current is higher than a preset fifth current value corresponding to the lowest battery temperature, the first charging current is changed to a 11th charging current of the fifth current value; if the charging current is lower than a preset fifth current value corresponding to the lowest battery temperature, the first charging current is changed to 0;

[0060] Within the above special temperature range, if the charging current is higher than a preset sixth current value corresponding to the highest temperature of the battery, the first charging current is changed to a 12th charging current of the sixth current value; if the charging current is lower than a preset seventh current value corresponding to the lowest temperature of the battery, the first charging current is changed to a 13th charging current of the seventh current value;

[0061] In the above end temperature range, if the charging current is lower than the eighth current value that is preset corresponding to the maximum temperature of the battery, the first charging current is determined as the 14th charging current of the eighth current value; if the charging current is higher than the eighth current value that is preset corresponding to the maximum temperature of the battery, the first charging current is changed to 0.

[0062] Alternatively, the voltage interval current setting module also changes the second charging current to 0 when the highest cell voltage of the battery is higher than a preset voltage threshold.

[0063] A third aspect of an embodiment of the present invention provides a vehicle including a vehicle controller;

[0064] The above vehicle controller executes the above arbitrary DC charging current determination method.

[0065] The method for determining a DC charging current provided by the present invention determines a first charging current as an upper limit of the allowable charging current at the current battery temperature and determines a second charging current as an upper limit of the allowable charging current at the current cell voltage of the battery, and then forms a third charging current by comparing the magnitudes of the first charging current and the second charging current, taking the minimum value, and correcting; since the third charging current takes the relatively smaller value between the two considering the battery temperature and cell voltage factors, not only is the charging current magnitude secured, but the charging current does not exceed the upper limit value according to the battery temperature and cell voltage factors.

[0066] Based on the third charging current, the fourth charging current is obtained as the allowable charging current upper limit at the current battery temperature retrieved from the table of maximum elevator voltmeters relative to the previously known maximum temperature, the magnitudes of the third charging current and the fourth charging current are compared, the smaller value is taken and added to the high-voltage accessory consumption current to obtain the DC charging current required for battery charging, and finally, the DC charging current is transmitted to the charging file.

[0067] Since the third charging current already takes into account the factors of battery temperature and cell voltage, it does not exceed the upper limit of the charging current based on these factors. Furthermore, by comparing it with the fourth charging current and taking the smaller value, the magnitude of the rapid charging current is additionally made more precise to satisfy the requirements for rapid charging current. Since it is a constant charging current that no longer changes linearly, it minimizes the impact on battery life and performance, making it highly practical.

[0068] The foregoing description is merely an overview of the technical solution of the present invention. To better understand the technical means of the present invention and to enable a clearer understanding of the invention, and to facilitate a clearer and easier understanding of the above objectives, other objectives, features, and advantages of the present invention, specific implementation methods of the present invention are specified below. Brief explanation of the drawing

[0069] Hereinafter, in order to explain the technical method of the embodiments of the present invention more clearly, the attached drawings described in some embodiments are briefly described, and the attached drawings described below represent some embodiments of the present invention, and a person skilled in the art can obtain other attached drawings based on these attached drawings without undergoing creative labor. FIG. 1 is a flowchart of a method for determining a DC charging current according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the specific temperature range and charging current value set in an embodiment of the present invention. FIG. 3 is a schematic diagram showing the specific voltage range and charging current value set in an embodiment of the present invention. FIG. 4 is a block diagram of a DC charging current determining device according to an embodiment of the present invention. FIG. 5 is a block diagram schematically showing a computer processing device for carrying out the method of the present invention. FIG. 6 is a schematic diagram showing a storage device for holding or transmitting program code for implementing a method according to the present invention. Specific details for implementing the invention

[0070] Hereinafter, the technical solution of the embodiments of the present invention is described clearly and completely in conjunction with the accompanying drawings of the embodiments of the present invention. The embodiments described herein are not all embodiments of the present invention, but merely partial embodiments. All other embodiments obtained by a person skilled in the art without creative labor based on the embodiments of the present invention are all within the scope of protection of the present invention.

[0071] The inventors have discovered that when setting the current rapid charging current, various factors must be considered and based on the requirements for reducing charging time. Generally, the rapid charging current changes linearly and has a large current value; a charging current that changes linearly and has a large current value may exceed the allowable upper limit of the charging current based on the current battery temperature and may exceed the allowable upper limit of the charging current based on the current battery cell voltage. Furthermore, the linear change of the charging current is unstable, so the current value may not continuously increase or decrease but may exhibit a change of repeatedly increasing or decreasing.

[0072] Therefore, all of the above situations have a serious impact on the battery's lifespan and performance, shortening its lifespan and degrading its performance, which indirectly degrades the user's driving experience. Furthermore, users may need to repair or replace the battery after a short period, indirectly increasing usage costs and reducing the user's sense of use.

[0073] In light of the above-mentioned problems, the inventors have creatively devised the method for determining the DC charging current of the present invention by conducting extensive research, calculations, simulations, and field tests. The technical solution of the present invention will be described in detail below.

[0074] FIG. 1 is a flowchart of a method for determining a DC charging current according to an embodiment of the present invention. The method comprises the following steps:

[0075] Step 101: Determine the first charging current based on the battery temperature.

[0076] In an embodiment of the present invention, before charging the electric vehicle, that is, before connecting the electric vehicle to a DC charging pile, a first charging current is first determined according to the battery temperature. The first charging current is the upper limit of the allowable charging current according to the current temperature of the battery.

[0077] In an embodiment of the present invention, in order to more accurately determine the upper limit of the allowable charging current according to the current temperature of the battery, the inventor creatively proposed the following concept:

[0078] After establishing multiple temperature ranges based on the initial battery temperature, a first charging current corresponding to each temperature range is established. In other words, multiple temperature ranges are established according to the current temperature at which the battery is to be charged. Due to the specific characteristics of the battery, temperature is a critical and sensitive factor. Generally, considering various factors such as battery operating efficiency, lifespan, and performance, electric vehicles are equipped with air conditioners and other equipment to heat and dissipate heat from the battery in order to maintain its temperature. However, in reality, battery temperatures inevitably vary depending on factors such as ambient temperature and operating conditions. Accordingly, the inventor established multiple temperature ranges based on the battery's current temperature, i.e., the initial temperature, and classified each temperature range in a more detailed and customized manner by considering various factors of the charging process. A detailed technical solution is described below, but a detailed explanation is omitted here.

[0079] Step 102: Determine the second charging current according to the battery cell voltage.

[0080] In an embodiment of the present invention, likewise, before charging the electric vehicle, that is, before connecting the electric vehicle to a DC charging pile, a second charging current must be determined according to the cell voltage of the battery. The second charging current is the upper limit of the allowable charging current according to the current cell voltage of the battery.

[0081] In an embodiment of the present invention, in order to more accurately determine the upper limit of the allowable charging current based on the current cell voltage factor of the battery, the inventor creatively proposed the following concept:

[0082] After setting multiple temperature ranges based on the battery's maximum cell voltage, a corresponding second charging current is set for each temperature range. In other words, multiple temperature ranges are set according to the current maximum cell voltage at which the battery is to be charged. Due to the specific characteristics of the battery, the maximum cell voltage is also a critical and sensitive factor. Generally, electric vehicles use battery modules, which contain multiple single cells; the cell voltage of each battery can vary depending on various factors such as operating efficiency, lifespan, performance, and manufacturing processes. However, in reality, due to factors such as manufacturing processes and operating conditions, the cell voltage of each battery inevitably changes as usage time increases, and the difference between voltage values ​​can become significant. Furthermore, since the voltage is the upper limit allowed when the battery is fully charged, the battery voltage naturally drops after use for a certain period. Similarly, the battery voltage is relatively low before charging and gradually rises as charging progresses, resulting in different cell voltage values ​​for each battery. Therefore, the inventor established multiple temperature ranges based on the battery's current maximum cell voltage and classified each temperature range in a more detailed and customized manner by considering various factors, such as voltage rise during the charging process. The detailed technical solution is described below, but a detailed explanation is omitted here.

[0083] Step 103: Compare the magnitudes of the first charging current and the second charging current, take the smaller value, and correct it to form the third charging current.

[0084] In an embodiment of the present invention, after determining the first and second charging currents, the magnitudes of the first and second charging currents are compared, the smaller value between them is taken, and a correction is applied to form a third charging current. The correction involves taking the smaller value between the first and second charging currents and subtracting the correction value to further lower the charging current, and the corrected smaller value is the third charging current. The reason for the correction is that the battery temperature value is an estimate and is inaccurate, and while the maximum cell voltage value is actually measured, an error exists. The correction value is proposed to resolve the problem of high charging current values ​​caused by inaccurate estimation and measurement errors. The correction value is a representative value obtained through extensive calculations, simulations, and actual measurements; it not only resolves the problem of high charging current values ​​caused by inaccurate estimation and measurement errors but also satisfies the charging current requirements for rapid charging. Therefore, the magnitudes of the first and second charging currents are compared, the smaller value is taken, and the correction is applied again to form the third charging current.

[0085] Of course, after comparing the first charging current and the second charging current, if the value of the first charging current is smaller, the third charging current is formed by the difference between the value of the first charging current and the correction value; and after comparing the first charging current and the second charging current, if the value of the second charging current is smaller, the third charging current is formed by the difference between the value of the second charging current and the correction value.

[0086] Step 104: Obtain the fourth charging current by consulting the maximum temperature and maximum elevator voltage table according to the battery temperature.

[0087] In an embodiment of the present invention, after determining the third charging current, the fourth charging current is obtained by querying the maximum temperature and maximum elevator voltage table according to the current battery temperature. The maximum temperature and maximum elevator voltage table is a table of charging currents corresponding to the current known battery temperature, and the charging current obtained based on said table is an upper limit value allowed at the current temperature, and is also a value that changes linearly. Through said table, the upper limit value of the charging current according to the current battery temperature can be obtained.

[0088] Step 105: Compare the magnitudes of the third charging current and the fourth charging current, take the smaller value, and add it to the current consumed by the high-voltage accessory to obtain the DC charging current required for battery charging.

[0089] In an embodiment of the present invention, after determining the third charging current and the fourth charging current, the magnitudes of the third charging current and the fourth charging current are compared again, the smaller value between the two is taken, and the high-voltage accessory consumption current is added again to finally obtain the DC charging current required for battery charging.

[0090] In an embodiment of the present invention, since the third charging current already takes into account the factors of the battery's current temperature and the current maximum cell voltage, it does not exceed the upper limit of the charging current according to the battery temperature and cell voltage. Therefore, by additionally eliminating all other possible factors that cause the problem of the charging current being determined to be high when comparing it again with the fourth charging current and taking the smaller value, the magnitude of the rapid charging current value is accurately determined and the rapid charging current requirements are satisfied. Furthermore, since the charging current is a constant charging current, there is no problem of exceeding the allowable upper limit of the charging current according to the battery's current temperature or the allowable upper limit of the charging current according to the battery's current cell voltage, there is no problem of the charging current value repeatedly increasing or decreasing, and the current rapid charging minimizes the impact on battery life and performance.

[0091] Finally, after obtaining the DC charging current required for battery charging, the value of the DC charging current must be transmitted to a charging device, such as a charging file, so that the electric vehicle can start charging. During the charging process, the charging current can be automatically determined again through the technical solution of steps 101 to 105 according to changes in battery temperature and cell voltage. During the charging process, since the battery temperature and cell voltage change slowly rather than rapidly, if the current battery temperature and current maximum cell voltage are within the current range, the charging current maintains a constant value and basically does not change; the charging current changes to a different value only when the current battery temperature or current maximum cell voltage changes to a different range, and after changing to a different value, it does not increase or decrease before changing to another range, and is always charged at the said value.

[0092] In the following, technical solutions for setting multiple temperature ranges according to the initial temperature of the battery and technical solutions for setting multiple voltage ranges according to the maximum cell voltage of the battery are described in detail, respectively, in embodiments of the present invention.

[0093] Regarding the initial battery temperature, due to the characteristics of the battery, an initial temperature range, a special temperature range, a termination temperature range, and a normal temperature range must be set.

[0094] The initial temperature range refers to a condition where the battery charges only when its current minimum temperature is higher than a specific value, and does not charge when it is lower than that value; this is intended to protect the battery. For example, as is currently known, charging is not possible if the initial minimum temperature is -20°C or lower, otherwise, it severely affects battery life and performance. Therefore, an initial temperature range must be set.

[0095] The special temperature range must consider that within the said temperature range, the charging current changes when the battery's maximum temperature rises above a specific value, and when the battery's minimum temperature falls below a specific value. For example, as is currently known, 15°C is a relatively special value; when the battery's maximum temperature is 15°C or higher, the charging current must be considered according to the battery's maximum temperature, and when it is 15°C or lower, the charging current must be considered according to the battery's minimum temperature. The said value is also a preset temperature threshold.

[0096] The termination temperature range means that the battery does not charge if its current maximum temperature is higher than a specific temperature value, and charges only when the current maximum temperature is lower than the said value; this is intended to protect the battery. For example, as is currently known, if the battery's initial minimum temperature is 55°C or higher, charging is not possible, otherwise it has a serious impact on battery life and performance. Therefore, a termination temperature range must be set.

[0097] The normal temperature range refers to a temperature range other than the initial temperature range, special temperature range, and end temperature range mentioned above. For each temperature range lower than a preset temperature threshold, if the battery temperature rises during the charging period, and the charging current rises above a preset first current value corresponding to the lowest temperature, the first charging current is changed to a fifth charging current of the first current value; and if the battery temperature rises during the charging period, and the charging current falls below a preset second current value corresponding to the lowest temperature, the first charging current is changed to a sixth charging current of the second current value.

[0098] For each temperature interval higher than a preset temperature threshold, if the battery temperature rises during the charging period, and the charging current rises above a preset third current value corresponding to the maximum temperature, the first charging current is changed to a seventh charging current of the third current value; if the battery temperature falls during the charging period, and the charging current falls below a preset fourth current value corresponding to the maximum temperature, the first charging current is changed to an eighth charging current of the fourth current value.

[0099] In an embodiment of the present invention, for an initial temperature range, if the charging current is greater than or equal to a preset fifth current value corresponding to the lowest temperature of the battery, the first charging current is changed to a 11th charging current of the fifth current value; if the charging current is lower than a preset fifth current value corresponding to the lowest temperature of the battery, the first charging current is changed to 0; for a special temperature range, if the charging current is greater than or equal to a preset sixth current value corresponding to the highest temperature of the battery, the first charging current is changed to a 12th charging current of the sixth current value; if the charging current is less than or equal to a preset seventh current value corresponding to the lowest temperature of the battery, the first charging current is changed to a 13th charging current of the seventh current value; for a termination temperature range, if the charging current is less than or equal to a preset eighth current value corresponding to the highest temperature of the battery, the first charging current is changed to a 14th charging current of the eighth current value; if the charging current is greater than or equal to a preset eighth current value corresponding to the highest temperature of the battery, the first charging current is changed to 0.

[0100] Regarding the setting of multiple temperature ranges and charging currents for each temperature range for the initial battery temperature above, we intend to explain this in more detail with reference to FIG. 2, which is a schematic diagram showing the setting of specific temperature ranges and charging current values ​​in an embodiment of the present invention.

[0101] 1) When the initial lowest battery temperature is -20℃ (Tmin ≤ -20℃ in Fig. 2), the charging current for the above temperature range is set to 0A (DC charger current = 0A in Fig. 2), that is, charging the battery is not allowed; later, when the battery temperature rises, if the lowest current battery temperature is -15℃ (Tmin ≥ -15℃ in Fig. 2) or higher, the charging current is changed to 7.8A * SOH (DC charger current = 7.8A * SOH in Fig. 2). SOH is an abbreviation for state of health, which means health status in Chinese.

[0102] 2) When the initial battery temperature is [-19℃, -6℃] (-19℃≤Tmin≤-6℃ in FIG. 2), the charging current for the above temperature range is changed to 7.8A*SOH (DC charger current=7.8A*SOH in FIG. 2); later, when the battery temperature rises, if the lowest current battery temperature is -3℃ (Tmin≥-3℃ in FIG. 2) or lower, the charging current is changed to 15.6A*SOH (DC charger current=15.6A*SOH in FIG. 2); similarly, when the battery temperature falls, if the lowest current battery temperature is -20℃ (Tmin≤-20℃ in FIG. 2) or lower, the charging current is changed to 0 (DC charger current=0A in FIG. 2).

[0103] 3) When the initial battery temperature is [-5℃, 4℃], the charging current for the above temperature range is set to 15.6A*SOH (DC charger current in Fig. 2 = 15.6A*SOH); later, when the battery temperature rises, if the lowest current battery temperature is 7℃ (Tmin ≥ 7℃ in Fig. 2), the charging current is changed to 31.2A*SOH (DC charger current in Fig. 2 = 31.2A*SOH); similarly, when the battery temperature falls, if the lowest current battery temperature is -8℃ (Tmin ≤ -8℃ in Fig. 2), the charging current is changed to 7.8A*SOH (DC charger current in Fig. 2 = 7.8A*SOH).

[0104] 4) When the initial battery temperature is [5℃, 14℃], the charging current for the above temperature range is set to 31.2A*SOH (DC charger current in Fig. 2 = 31.2A*SOH); later, when the battery temperature rises, if the maximum current battery temperature is 15℃ (Tmax ≥ 15℃ in Fig. 2) or higher, the charging current is changed to 78A*SOH (DC charger current in Fig. 2 = 78A*SOH); similarly, when the battery temperature falls, if the minimum current battery temperature is 3℃ (Tmin ≤ 3℃ in Fig. 2) or lower, the charging current is changed to 15.6A*SOH (DC charger current in Fig. 2 = 15.6A*SOH).

[0105] 5) When the initial battery temperature is [15℃, 19℃], the charging current for the above temperature range is set to 78A*SOH (DC charger current = 78A*SOH in Fig. 2); later, when the battery temperature rises, if the maximum current temperature of the battery is 22℃ (Tmax ≥ 22℃ in Fig. 2) or higher, the charging current is changed to 156A*SOH (DC charger current = 156A*SOH in Fig. 2); similarly, when the battery temperature falls, if the maximum current temperature of the battery is 13℃ (Tmax ≤ 13℃ in Fig. 2) or lower, the charging current is changed to 31.2A*SOH (DC charger current = 31.2A*SOH in Fig. 2).

[0106] 6) When the initial battery temperature is [20℃, 40℃], the charging current for the above temperature range is set to 156A*SOH (DC charger current = 156A*SOH in FIG. 2); later, when the battery temperature rises, if the maximum current temperature of the battery is 43℃ ​​(Tmax ≥ 43℃ in FIG. 2) or higher, the charging current is changed to 51A*SOH (DC charger current = 51A*SOH in FIG. 2); similarly, when the battery temperature falls, if the maximum current temperature of the battery is 17℃ (Tmax ≤ 17℃ in FIG. 2) or lower, the charging current is changed to 78A*SOH (DC charger current = 78A*SOH in FIG. 2).

[0107] 7) When the initial battery temperature is [41℃, 52℃], the charging current for the above temperature range is set to 51A*SOH (DC charger current = 51A*SOH in Fig. 2); later, when the battery temperature rises, if the maximum current temperature of the battery is 53℃ (Tmax ≥ 53℃ in Fig. 2) or higher, the charging current is changed to 15.6A*SOH (DC charger current = 15.6A*SOH in Fig. 2); similarly, when the battery temperature falls, if the maximum current temperature of the battery is 38℃ (Tmax ≤ 38℃ in Fig. 2) or lower, the charging current is changed to 156A*SOH (DC charger current = 156A*SOH in Fig. 2).

[0108] 8) When the initial battery temperature is [53℃, 54℃], the charging current for the above temperature range is set to 15.6A*SOH (DC charger current in Fig. 2 = 15.6A*SOH); later, when the battery temperature rises, if the maximum current temperature of the battery is 55℃ (Tmax ≥ 55℃ in Fig. 2) or higher, the charging current is changed to 0A (DC charger current in Fig. 2 = 0A); similarly, when the battery temperature falls, if the maximum current temperature of the battery is 50℃ (Tmax ≤ 50℃ in Fig. 2) or lower, the charging current is changed to 51A*SOH (DC charger current in Fig. 2 = 51A*SOH).

[0109] 9) When the initial maximum temperature of the battery is 55℃ (Tmax=55℃ in Fig. 2), the charging current in the above temperature range is set to 0 (DC charger current=0A in Fig. 2), that is, charging is not allowed and the battery must be cooled. When the battery temperature decreases, if the maximum current temperature of the battery is 54℃ (Tmax≤54℃ in Fig. 2) or lower, the charging current is changed to 15.6A*SOH (DC charger current=15.6A*SOH in Fig. 2).

[0110] Among the above 9 temperature ranges, the temperature range where the initial minimum battery temperature is -20℃ or lower is the initial temperature range, the temperature range where the initial battery temperature is [5℃, 14℃] is the special temperature range, the temperature range where the initial maximum battery temperature is 55℃ or higher is the termination temperature range, and the rest are normal temperature ranges.

[0111] Generally, the battery temperature naturally rises slowly during the charging process; however, if the external ambient temperature is poor, the battery may charge but the temperature may drop. Of course, if various conditions and factors permit, the battery can be heated using a heating function to improve the temperature and ensure it charges in an optimal state.

[0112] In the case of the battery cell voltage, since the battery cell voltage increases with charging due to the battery characteristics, multiple voltage ranges are set according to the maximum cell voltage of the battery, and a second charging current corresponding to each voltage range is set;

[0113] Here, if the charging voltage during the charging period is lower than a preset first voltage value corresponding to the maximum cell voltage of the battery, the second charging current is changed to a ninth charging current of the first voltage value; and if the charging voltage during the charging period is higher than a preset first voltage value corresponding to the maximum cell voltage of the battery and simultaneously lower than a preset second voltage value, the second charging current is changed to a tenth charging current of the second voltage value. In another special situation, if the charging voltage is higher than a voltage threshold corresponding to the maximum cell voltage of the battery, the second charging current is changed to 0. For example, if the preset voltage threshold of the battery is 4.2V, the battery can no longer be charged when the maximum cell voltage of the battery reaches 4.2V.

[0114] Regarding the setting of multiple voltage ranges and charging currents for each voltage range for the maximum cell voltage of the battery above, we intend to explain this in more detail with reference to FIG. 3, which is a schematic diagram showing the setting of specific voltage ranges and charging current values ​​in an embodiment of the present invention.

[0115] Seven voltage ranges are set according to the maximum cell voltage of the battery, including a voltage range where the maximum cell voltage is lower than V1 (Maximum cell voltage < V1 in Fig. 3), a voltage range where the maximum cell voltage is greater than V1 and lower than V2 (V1 ≤ Maximum cell voltage < V2 in Fig. 3), a voltage range where the maximum cell voltage is greater than V2 and lower than V3 (V2 ≤ Maximum cell voltage < V3 in Fig. 3), a voltage range where the maximum cell voltage is greater than V3 and lower than V4 (V3 ≤ Maximum cell voltage < V4 in Fig. 3), a voltage range where the maximum cell voltage is greater than V4 and lower than V5 (V4 ≤ Maximum cell voltage < V5 in Fig. 3), a voltage range where the maximum cell voltage is greater than V5 and lower than V6 (V5 ≤ Maximum cell voltage < V6 in Fig. 3), and a voltage range where the maximum cell voltage is greater than 4.2 (Maximum cell voltage ≥ 4.2 in Fig. 3).

[0116] Here, the values ​​of V1, V2, V3, V4, V5, and V6 are as shown in the following table. That is:

[0117]

[0118] If the current maximum cell voltage of the battery is located in a voltage range lower than V1 (Maximum cell voltage < V1 in FIG. 3), the charging current for said voltage range is set to 15.6 A (15.6 A * SOH in FIG. 3); if the current maximum cell voltage of the battery is located in a voltage range greater than V1 and lower than V2 (V1 ≤ Maximum cell voltage < V2 in FIG. 3), or if the current maximum cell voltage of the battery rises to a voltage range greater than V1 and lower than V2 (V1 ≤ Maximum cell voltage < V2 in FIG. 3) along with charging, the charging current for said voltage range is changed to 156 A (156 A * SOH in FIG. 3); When the current maximum cell voltage of the battery is in a voltage range higher than V2 and lower than V3 (V2≤Maximum cell voltage<V3 in FIG. 3), or when the current maximum cell voltage of the battery rises to a voltage range higher than V2 and lower than V3 (V2≤Maximum cell voltage<V3 in FIG. 3) along with charging, the charging current of the voltage range is changed to 109.2 A (109.2 A*SOH in FIG. 3).

[0119] When the current maximum cell voltage of the battery is in a voltage range higher than V3 and lower than V4 (V3≤Maximum cell voltage<V4 in FIG. 3), or when the current maximum cell voltage of the battery rises to a voltage range higher than V3 and lower than V4 (V3≤Maximum cell voltage<V4 in FIG. 3) along with charging, the charging current of the voltage range is changed to 78 A (78A*SOH in FIG. 3); when the current maximum cell voltage of the battery is in a voltage range higher than V4 and lower than V5 (V4≤Maximum cell voltage<V5 in FIG. 3), or when the current maximum cell voltage of the battery rises to a voltage range higher than V4 and lower than V5 (V4≤Maximum cell voltage<V5 in FIG. 3) along with charging, the charging current of the voltage range is changed to 51.5 A (51.5A*SOH in FIG. 3).

[0120] When the current maximum cell voltage of the battery is in a voltage range higher than V5 and lower than V6 (V5≤Maximum cell voltage<V6 in FIG. 3), or when the current maximum cell voltage of the battery rises to a voltage range higher than V5 and lower than V6 (V5≤Maximum cell voltage<V6 in FIG. 3) along with charging, the charging current of the voltage range is changed to 15.6 A (15.6A*SOH in FIG. 3); when the current maximum cell voltage of the battery is in a voltage range higher than 4.2V (Maximum cell voltage≥4.2 in FIG. 3), or when the current maximum cell voltage of the battery rises to a voltage range higher than 4.2V (Maximum cell voltage≥4.2 in FIG. 3) along with charging, the charging current of the voltage range is changed to 0 A (0 A in FIG. 3).

[0121] In conjunction with the above example, a simple example of the method for determining the DC charging current of an embodiment of the present invention will be explained. That is: assuming the initial battery temperature is 26℃ and the maximum cell voltage is 3.98V, based on the initial temperature of 26℃, it falls within the [20℃, 40℃] temperature range and the set charging current is 156A*SOH, but based on the maximum cell voltage of 3.98V, it falls within the voltage range greater than 3.875V and lower than 4.13V and the set charging current is 109.2A*SOH. Next, when comparing the magnitudes of the two charging currents and taking the smaller value, the charging current is 109.2 A*SOH. The above value must be corrected again. Assuming the correction value is 1.2, the corrected charging current is 108 A*SOH. Then, when querying the maximum temperature and maximum elevator voltage table according to the battery temperature of 26℃, the corresponding charging current is 156 A*SOH. When comparing the two and taking the smaller value, the charging current is 108 A*SOH. Then, it is added again with the high-voltage accessory consumption current. Assuming the high-voltage accessory consumption current is 10 A*SOH, finally, the DC charging current required for battery charging is 118 A*SOH, and the above value is transmitted to the charging file. After that, when the battery temperature rises above the maximum temperature of 43℃, the corresponding charging current is 51 A*SOH. The corresponding charging current is determined again according to the current maximum cell voltage, and the above steps are repeated to obtain the DC charging current required for battery charging, and the above new value is transmitted to the charging file.

[0122] An embodiment of the present invention also provides a DC charging current determining device, FIG. 4 is a block diagram of a DC charging current determining device according to an embodiment of the present invention, and the device is,

[0123] A first determination module (410) for determining a first charging current according to the battery temperature;

[0124] A second determination module (420) for determining a second charging current according to the cell voltage of the battery;

[0125] A comparison and correction module (430) for forming a third charging current by comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting;

[0126] A table lookup module (440) for obtaining a fourth charging current by looking up a table of maximum temperature and maximum elevator voltage according to the battery temperature;

[0127] It includes a charging current determination module (450) for determining the DC charging current required for battery charging by comparing the magnitudes of the third charging current and the fourth charging current, taking the smaller value, and adding it to the consumption current of the high-voltage accessory.

[0128] Alternatively, the above device,

[0129] Temperature range setting module for setting multiple temperature ranges according to the initial battery temperature;

[0130] It further includes a temperature range current setting module for setting a first charging current corresponding to each temperature range, and

[0131] Herein, for each temperature interval lower than a preset temperature threshold, when the charging current rises above a preset first current value corresponding to the lowest temperature of the battery during the charging period, the first charging current is changed to a fifth charging current of the first current value; and when the charging current falls below a preset second current value corresponding to the lowest temperature of the battery during the charging period, the first charging current is changed to a sixth charging current of the second current value;

[0132] Here, for each temperature interval higher than a preset temperature threshold, when the charging current rises above a preset third current value corresponding to the maximum temperature of the battery during the charging period, the first charging current is changed to a seventh charging current of the third current value; and when the charging current falls below a preset fourth current value corresponding to the maximum temperature of the battery during the charging period, the first charging current is changed to an eighth charging current of the fourth current value.

[0133] Alternatively, the above device,

[0134] Voltage range setting module for setting multiple voltage ranges according to the maximum cell voltage of the battery;

[0135] It further includes a voltage range current setting module for setting a second charging current corresponding to each voltage range, and

[0136] Here, if the charging voltage during the charging period is lower than a preset first voltage value corresponding to the highest cell voltage of the battery, the second charging current is changed to a ninth charging current of the first voltage value;

[0137] During the charging period, if the charging voltage is greater than a preset first voltage value corresponding to the maximum cell voltage of the battery and simultaneously lower than a preset second voltage value, the second charging current is changed to a 10th charging current of the second voltage value.

[0138] Alternatively, the comparison and correction module (430) above is,

[0139] A comparison unit for comparing the magnitudes of the first charging current and the second charging current and taking the smaller value;

[0140] When the value of the first charging current is small, the third charging current is formed by the difference between the value of the first charging current and the correction value, and

[0141] Additionally, when the value of the second charging current is small, it includes a correction unit for forming the third charging current with the difference between the value of the second charging current and the correction value.

[0142] Alternatively, the temperature range setting module also sets an initial temperature range, a special temperature range, and an end temperature range according to the battery initial temperature;

[0143] The temperature range current setting module also sets a first charging current corresponding to the initial temperature range, the special temperature range, and the end temperature range, respectively;

[0144] Herein, within the initial temperature range, if the charging current is higher than a preset fifth current value corresponding to the lowest temperature of the battery, the first charging current is changed to a 11th charging current of the fifth current value; if the charging current is lower than a preset fifth current value corresponding to the lowest temperature of the battery, the first charging current is changed to 0;

[0145] Within the above special temperature range, if the charging current is higher than a preset sixth current value corresponding to the maximum temperature of the battery, the first charging current is changed to a 12th charging current of the sixth current value; if the charging current is lower than a preset seventh current value corresponding to the minimum temperature of the battery, the first charging current is changed to a 13th charging current of the seventh current value;

[0146] In the above end temperature range, if the charging current is lower than the eighth current value that is preset corresponding to the maximum temperature of the battery, the first charging current is changed to the 14th charging current of the eighth current value; if the charging current is higher than the eighth current value that is preset corresponding to the maximum temperature of the battery, the first charging current is changed to 0.

[0147] Alternatively, the voltage interval current setting module also changes the second charging current to 0 when the highest cell voltage of the battery is higher than a preset voltage threshold.

[0148] An embodiment of the present invention also provides a vehicle comprising a vehicle controller, wherein the vehicle controller executes the method for determining a DC charging current of any one of steps 101 to 105.

[0149] According to the above embodiment, since the DC charging current determination method of the embodiment of the present invention integrally considers battery temperature and cell voltage factors, it does not exceed the upper limit of the charging current based on battery temperature and cell voltage factors, and takes the smaller value by comparing it with the charging current obtained by querying a table, thereby making the magnitude of the charging current value even more accurate and satisfying the rapid charging current requirements. Furthermore, it does not exceed the upper limit of the charging current based on battery temperature and cell voltage factors, there is no problem of exceeding the allowable upper limit of the charging current based on the current battery temperature or the current cell voltage, there is no problem of the charging current value repeatedly increasing or decreasing, and the current rapid charging minimizes the impact on battery life and performance.

[0150] The aforementioned device embodiments are merely examples, and the units described herein as separate parts may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Depending on actual needs, some or all modules may be selected to realize the purpose of the technical solution of the present embodiment. Those skilled in the art can understand and practice the present invention without requiring creative labor.

[0151] Embodiments of each component of the present invention may be implemented by hardware or by software modules running on one or more processors, or by a combination thereof. Those skilled in the art will understand that in actual use, a microprocessor or a digital signal processor (DSP) may be used to implement some or all functions of some or all components of a server according to an embodiment of the present invention. The present invention may also be implemented as a device or a program of a device (e.g., a computer program and a computer program product) for performing some or all of the methods described herein. Such a program for implementing the present invention may be stored on a computer-readable medium or may have one or more signal forms. Such signals may be downloaded from an internet website or provided as carrier signals or in other forms.

[0152] For example, FIG. 5 illustrates a computing processing device for implementing a method according to the present invention. The computing processing device generally includes a computer program product or a computer-readable medium in the form of a processor (1010) and memory (1020). The memory (1020) may be an electronic memory such as flash memory, Electrically Erasable Programmable Read Only Memory (EEPROM), EPROM, hard disk, or ROM. The memory (1020) has a storage space (1030) for storing program code (1031) for performing any method step of the method. For example, the storage space (1030) for storing program code may contain respective program codes (1031) for implementing various steps of the method. Such program code may be read or written from one or more computer program products. Such computer program products include a medium capable of storing program code, such as a hard disk, CD, memory card, or floppy disk. Such computer program products are generally portable or fixed storage units as illustrated in FIG. 6. The above storage unit may have a storage section, storage space, etc. arranged similarly to the memory (1020) of the computing processing device of FIG. 5. Program code may be compressed into an appropriate format. Generally, the storage unit may include computer-readable code (1031'), such as code that can be read by an electronic device such as a processor (1010), and such code is executed by the computing processing device so that the electronic device performs various steps of the method.

[0153] In this specification, “include,” “contain,” or other variations refer to non-exclusive inclusion, and a process, method, article, or device comprising a series of elements comprises not only those elements but also other elements not explicitly listed, or elements unique to such process, method, article, or device. Unless otherwise limited, an element defined as “includes” does not exclude the presence of other identical elements in a process, method, article, or device comprising said element.

[0154] As described above, although embodiments of the present invention have been explained in conjunction with the attached drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments are merely illustrative and not restrictive. Those skilled in the art may make various modifications based on the present invention without departing from the scope of protection according to the claims and the purpose of the present invention, and all such modifications fall within the scope of protection of the present invention.

Claims

Claim 1 A method for determining a DC charging current, comprising: a step of determining a first charging current as an upper limit of the charging current allowed at the current battery temperature; a step of determining a second charging current as an upper limit of the charging current allowed at the current cell voltage of the battery; a step of comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and then correcting with a preset correction value to form a third charging current lower than the first charging current and the second charging current, thereby compensating for the measurement error of each of the current battery temperature and the current cell voltage of the battery; a step of obtaining a fourth charging current as an upper limit of the charging current allowed at the current battery temperature retrieved from a maximum elevator voltmeter stored in a table form corresponding to the maximum battery temperature; and a step of comparing the magnitudes of the third charging current and the fourth charging current, taking the smaller value, and adding it to the consumption current of a high-voltage accessory to obtain a DC charging current required for battery charging; wherein the magnitude of the charging current is maintained constant when the current battery temperature and the current cell voltage of the battery fluctuate. Claim 2 In claim 1, prior to the step of determining the first charging current, the method further comprises: a step of setting a plurality of temperature ranges according to the initial temperature of the battery; and a step of setting a first charging current corresponding to each temperature range; wherein, for each temperature range where the current temperature of the battery is lower than a preset temperature threshold, when the charging current rises above a preset first current value corresponding to the lowest temperature of the battery during the charging period, the first charging current is changed to a fifth charging current of the first current value; when the charging current falls below a preset second current value corresponding to the lowest temperature of the battery during the charging period, the first charging current is changed to a sixth charging current of the second current value; and wherein, for each temperature range where the current is higher than a preset temperature threshold, when the charging current rises above a preset third current value corresponding to the highest temperature of the battery during the charging period, the first charging current is changed to a seventh charging current of the third current value. A method for determining a DC charging current characterized by changing the first charging current to the eighth charging current of the fourth current value when the charging current drops below a preset fourth current value corresponding to the maximum temperature of the battery during the charging period. Claim 3 A method for determining a DC charging current according to claim 1, further comprising, prior to the step of determining a second charging current according to the cell voltage of the battery, a step of setting multiple voltage intervals according to the maximum cell voltage of the battery; and a step of setting a second charging current corresponding to each voltage interval; wherein, if the charging voltage during the charging period is lower than a preset first voltage value corresponding to the maximum cell voltage of the battery, the second charging current is changed to a ninth charging current of the first voltage value; and if the charging voltage during the charging period is greater than a preset first voltage value corresponding to the maximum cell voltage of the battery and simultaneously lower than a preset second voltage value, the second charging current is changed to a tenth charging current of the second voltage value. Claim 4 A method for determining a DC charging current according to claim 1, wherein the step of comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting to form a third charging current comprises: a step of comparing the magnitudes of the first charging current and the second charging current and taking the smaller value; a step of forming the third charging current by the difference between the value of the first charging current and the corrected value when the value of the first charging current is small; and a step of forming the third charging current by the difference between the value of the second charging current and the corrected value when the value of the second charging current is small. Claim 5 In claim 1, the method further comprises the steps of: setting an initial temperature range, a special temperature range, and a termination temperature range according to the initial temperature of the battery; and setting a first charging current corresponding to each of the initial temperature range, the special temperature range, and the termination temperature range, wherein, within the initial temperature range, if the charging current is higher than a preset fifth current value corresponding to the lowest temperature of the battery, the first charging current is changed to a first charging current of the fifth current value; if the charging current is lower than a preset fifth current value corresponding to the lowest temperature of the battery, the first charging current is changed to zero; and within the special temperature range, if the charging current is higher than a preset sixth current value corresponding to the highest temperature of the battery, the first charging current is changed to a second charging current of the sixth current value. A method for determining a DC charging current, characterized by: changing the first charging current to a 13th charging current of the 7th current value when the charging current is lower than a preset 7th current value corresponding to the lowest temperature of the battery; changing the first charging current to a 14th charging current of the 8th current value when the charging current is lower than a preset 8th current value corresponding to the highest temperature of the battery within the end temperature range; and changing the first charging current to 0 when the charging current is higher than a preset 8th current value corresponding to the highest temperature of the battery. Claim 6 A method for determining a DC charging current according to claim 1, further comprising the step of changing the second charging current to 0 when the maximum cell voltage of the battery is higher than a preset voltage threshold. Claim 7 A DC charging current determining device comprising: a first determination module for determining a first charging current as an upper limit of the charging current allowed at the current battery temperature; a second determination module for determining a second charging current as an upper limit of the charging current allowed at the current cell voltage of the battery; a comparison and correction module for compensating for measurement errors of the current battery temperature and the current cell voltage of the battery by forming a third charging current lower than the first charging current and the second charging current by comparing the magnitudes of the first charging current and the second charging current, taking the smaller value, and correcting with a preset correction value; a table inquiry module for obtaining a fourth charging current as an upper limit of the charging current allowed at the current battery temperature, which is queried from a maximum elevator voltmeter stored in a table form corresponding to the maximum battery temperature; and a charging current determining module for determining a DC charging current required for battery charging by comparing the magnitudes of the third charging current and the fourth charging current, taking the smaller value, and adding it to the consumption current of a high-voltage accessory. The DC charging current determining device is characterized by being configured such that the magnitude of the charging current is maintained constant when the current battery temperature and the current cell voltage of the battery fluctuate. Claim 8 In claim 7, the device further comprises: a temperature range setting module for setting multiple temperature ranges according to the initial temperature of the battery; and a temperature range current setting module for setting a first charging current corresponding to each temperature range; wherein for each temperature range where the current temperature of the battery is lower than a preset temperature threshold, when the charging current rises above a preset first current value corresponding to the lowest temperature of the battery during the charging period, the first charging current is changed to a fifth charging current of the first current value; and when the charging current falls below a preset second current value corresponding to the lowest temperature of the battery during the charging period, the first charging current is changed to a sixth charging current of the second current value; and wherein, for each temperature range where the current is higher than a preset temperature threshold, when the charging current rises above a preset third current value corresponding to the highest temperature of the battery during the charging period, the first charging current is changed to a seventh charging current of the third current value; A DC charging current determining device characterized by changing the first charging current to the eighth charging current of the fourth current value when the charging current drops below a preset fourth current value corresponding to the maximum temperature of the battery during the charging period. Claim 9 A DC charging current determining device according to claim 7, wherein the device further comprises: a voltage range setting module for setting multiple voltage ranges according to the maximum cell voltage of the battery; and a voltage range current setting module for setting a second charging current corresponding to each voltage range, wherein, if the charging voltage during the charging period is lower than a preset first voltage value corresponding to the maximum cell voltage of the battery, the second charging current is changed to a ninth charging current of the first voltage value; and if the charging voltage during the charging period is greater than a preset first voltage value corresponding to the maximum cell voltage of the battery and simultaneously lower than a preset second voltage value, the second charging current is changed to a tenth charging current of the second voltage value. Claim 10 A DC charging current determining device according to claim 7, wherein the comparison and correction module comprises: a comparison unit for taking the smaller value by comparing the magnitudes of the first charging current and the second charging current; and a correction unit for forming the third charging current by the difference between the value of the first charging current and the correction value when the value of the first charging current is small, and also forming the third charging current by the difference between the value of the second charging current and the correction value when the value of the second charging current is small. Claim 11 A vehicle characterized by including a vehicle controller for executing a method for determining a DC charging current according to any one of claims 1 to 6. Claim 12 A computing processing device comprising: a memory in which computer-readable code is stored; and one or more processors; wherein the method for determining a DC charging current of any one of claims 1 to 6 is performed by the computing processing device by executing the computer-readable code by one or more processors. Claim 13 A computer program stored in a computer-readable recording medium, characterized in that the computer-readable code is executed by a computing processing device, thereby enabling the computing processing device to perform a method for determining a direct current charging current according to any one of claims 1 to 6. Claim 14 A computer-readable medium characterized by having the computer program of claim 13 stored thereon.

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