Battery charging balance maintenance method for pure electric wide-body dump truck

Abstract

The invention discloses a battery charging balance maintenance method for a pure electric wide-body dumper, and belongs to the technical field of battery charging. And the VCU detects the maximum voltage value of the single battery, the dynamic voltage difference of the battery core and the cycle index, timely adjusts the requested output constant-current charging current value, and reduces the requested output constant-current charging current value and the requested current of the BMS according to the charging current MAP to charge the battery pack. By dynamically adjusting the charging current of the battery pack, when the voltage is small, the original charging current MAP request logic of the battery system is maintained, the battery pack is charged with the constant charging current, the battery is rapidly charged, and when the voltage is high and when the dynamic voltage difference change of the battery core is large and the charging cycle times are large, the charging efficiency is high. The VCU requests to output the constant-current charging current value and the charging current MAP requests that the current is small, stable charging is carried out, energy waste in the charging process is reduced, battery damage in the charging process is reduced, and the maintenance frequency of the battery is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of battery charging, and in particular relates to a battery charging and balancing maintenance method for a pure electric wide-body dump truck. Background Art

[0002] With the increasing attention paid to environmental protection and energy efficiency around the world, the use of new energy equipment is becoming more and more widespread, especially in the field of large-scale mechanical equipment, such as wide-body mining trucks. However, these devices usually require large power and long working hours, and they work at full load for at least 20 hours a day, which brings challenges to the battery power, charging efficiency and maintenance of the power battery system of the equipment. The traditional solution is usually to stack up the battery power to ensure the equipment's operating efficiency and high-power charging and discharging needs, and then use a multi-gun (three or four guns or more) charging device for rapid energy replenishment. Long-term high-current charging and discharging, the battery system does not have enough static maintenance time, resulting in high charging and low discharge of the battery system, accelerating the battery attenuation rate, and even polarization and over-discharge lithium deposition risks for a long time. However, once the equipment is shut down for maintenance, the time is too long, which is easy to affect the equipment's operating efficiency.

[0003] The existing technical solution is to obtain battery parameters at preset time intervals during the battery charging process; when the battery voltage is within a preset voltage range, determine the target charging current according to the battery voltage; output a control signal to control the target charging current to charge the battery; and continuously change the charging current to charge the battery, which can improve the efficiency of battery charging, effectively reduce the generation of internal polarization resistance during battery charging, and reduce battery heating. Therefore, the existing technical solution mainly divides the battery charging process into: constant current charging and constant voltage charging process. At the same time, the battery parameters are obtained at preset time intervals, and the battery parameters can be monitored in real time during the battery charging process to ensure the safety of the battery charging process. Battery maintenance is mainly carried out by periodically discharging the power battery to a SOC below 20%, and resting for more than 2 hours, and then performing full charge calibration through the above-mentioned charging control method.

[0004] Although the above-mentioned charging control method and battery static maintenance can meet the battery system use requirements, in large-tonnage equipment, when the battery system's charging and discharging power is large and the SOC is below 20%, the battery system's discharge performance is weak and cannot meet the requirements of continuous high-power discharge, resulting in the power battery system being in the 20% to 90% operating range for a long time, which is more likely to cause the problem of high charging and low discharge, and thus requires a higher frequency of battery maintenance and static maintenance; secondly, since most electric mining trucks use a multi-gun high-current energy replenishment solution, during the constant-voltage charging process to control the charging current, due to the constant-voltage charging at the end, the current changes in real time and the multi-gun charging current is large, the charging device follows the output target charging current change at an insufficient rate, and the battery system is prone to reporting a charging overcurrent fault. Summary of the invention

[0005] 1. Technical problem to be solved by the invention

[0006] The purpose of the present invention is to solve the problem that the existing charging method cannot meet the needs of long-term operation of large-tonnage and large-capacity equipment, and the problem that the power battery needs to be frequently stationary for maintenance during the use of the equipment.

[0007] 2. Technical solution

[0008] In order to achieve the above object, the technical solution provided by the present invention is:

[0009] A battery charging and balancing maintenance method for a pure electric wide-body dump truck of the present invention,

[0010] S1. During the battery charging process, the vehicle VCU detects the maximum voltage value of the battery cell and determines whether the current maximum voltage value of the cell is within the threshold C or threshold D. When the maximum voltage value of the cell is within the threshold C range, step S2 is executed; when the maximum voltage value of the cell is within the threshold D range, step S3 is executed;

[0011] S2. During the battery charging process, the vehicle VCU detects the dynamic voltage difference of the battery cell and determines whether it is less than the threshold value U1. When the detected dynamic voltage difference of the battery cell is less than the threshold value U1, step S4 is executed; when the detected dynamic voltage difference of the battery cell is not less than the threshold value U1, step S5 is executed;

[0012] S3. During the battery charging process, the vehicle VCU detects the dynamic voltage difference of the battery cell and the number of charging cycles, and determines whether the dynamic voltage difference of the battery cell is greater than the threshold value U2 and whether the number of charging cycles cycle is greater than the threshold value N. When the dynamic voltage difference of the battery cell is greater than the threshold value U2 and the number of charging cycles cycle is greater than the threshold value N, step S6 is executed; when the dynamic voltage difference of the battery cell is not greater than the threshold value U2 or the number of charging cycles cycle is not greater than the threshold value N, step S7 is executed;

[0013] S4, maintaining the original charging current MAP request logic of the battery system, and charging the battery pack with a constant current value I0;

[0014] S5. The vehicle VCU requests the output of a constant current charging current value I1. The BMS requests the current I0 based on the charging current MAP and takes the smaller value of the constant current charging current value I1, and outputs the final requested charging current value (I1, I0)min to charge the battery pack.

[0015] S6, request the output of constant current charging current value I through the vehicle VCU 1i , BMS requests current I according to the charging current MAP 0i With constant current charging current value I1i Take the smaller value and output the final requested charging current value (I 1i , I 0i )min, charge the battery pack;

[0016] S7, BMS requests current I according to charging current MAP 0i , to request current I 0i Charge the battery pack.

[0017] Preferably, during the battery charging process from step S1 to step S7, I 1i and I 0i As the battery cell voltage value changes in real time and outputs the minimum value to charge the battery pack, when the vehicle VCU detects that the voltage rise rate of the charging terminal cell exceeds threshold A or the voltage difference increase rate exceeds threshold B or I 0i When the reduction rate exceeds the threshold E, the vehicle VCU actively intervenes to reduce the constant current charging current value I 1i , BMS requests current I according to the charging current MAP 0i The constant current charging current value I 1i Take the smaller value and output the final requested charging current value (I 1i , I 0i )min, charge the battery pack.

[0018] Preferably, the threshold A is 0.06 mv / s, the threshold B is 250 mv, and the threshold E is 20 A / s.

[0019] Preferably, in step S1, the range of the monomer maximum voltage threshold C is (3.0V, 3.55V), the range of the threshold C is the constant current charging control stage, the range of the threshold D is (3.55V, 3.7V), and the range of the threshold D is the constant voltage charging control stage.

[0020] Preferably, in step S3, the battery cell dynamic voltage difference threshold U1 is 200mv.

[0021] Preferably, in step S4, the battery cell dynamic voltage difference threshold U2 is 250mv, and the cycle number threshold N is 10 times.

[0022] Preferably, the charging equalization maintenance method includes three charging modes:

[0023] (1) Mode 1: Charging control is performed with the original charging current MAP of the battery system BMS, which is divided into a constant current charging control stage and a constant voltage charging control stage. In the constant current charging control stage, the charging current is I0, and in the constant voltage charging control stage, the charging current is I 0i ;

[0024] (2) Mode 2: In the constant voltage charging control stage, the BMS requests the current I according to the charging current MAP. 0i The constant current charging current value I 1i Take the small control to charge the battery pack;

[0025] (3) Mode 3: Full stage, BMS requests current I according to charging current MAP 0i The constant current charging current value I 1i Take a small control and charge the battery pack.

[0026] 3. Beneficial effects

[0027] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0028] A battery charging and balancing maintenance method for a pure electric wide-body dump truck of the present invention is specifically as follows: a VCU detects the maximum voltage value of a battery cell, a dynamic voltage difference of a battery cell, and the number of cycles, timely adjusts the requested output constant current charging current value, and takes the smaller of the requested output constant current charging current value and the requested current according to a charging current MAP of the BMS to charge the battery pack. The present invention dynamically adjusts the charging current of the battery pack. When the voltage is low, the original charging current MAP request logic of the battery system is maintained, and the battery pack is charged with a constant charging current to quickly charge the battery. When the voltage is high and when the dynamic voltage difference of the battery cell changes greatly and the number of charging cycles is large, the VCU requests to output a constant charging current value that is smaller than the charging current MAP request current, so as to perform stable charging, reduce energy waste during charging, reduce battery damage during charging, and reduce the frequency of battery maintenance. At the same time, large-tonnage and large-capacity equipment must be matched with large-capacity power batteries. However, large-capacity batteries often have the problem of charging high and discharging low during use, which affects the service life and charge of the power battery. The charging balancing maintenance method of the present application can improve the service life and duration of large-tonnage and large-capacity equipment to meet the needs of long-term operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of a battery charging and equalization maintenance method for a pure electric wide-body dump truck of the present invention;

[0030] Figure 2 The present invention is a schematic diagram of a charging mode of a battery charging and balancing maintenance method for a pure electric wide-body dump truck. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] In this application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "center", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0034] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0035] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] Example 1

[0038] See attached Figure 1-2 , a battery charging and balancing maintenance method for a pure electric wide-body dump truck of this embodiment is specifically as follows:

[0039] S1. During the battery charging process, the vehicle VCU detects the maximum voltage value of the battery cell and determines whether the current maximum voltage value of the cell is within the threshold C or threshold D range. When the maximum voltage value of the cell is within the threshold C range, step S2 is executed. When the maximum voltage value of the cell is within the threshold D range, step S3 is executed. The vehicle VCU detects the maximum voltage value of the battery cell and determines the range. The vehicle VCU charges the battery pack according to different charging logics to improve charging efficiency.

[0040] S2. During the battery charging process, the vehicle VCU detects the dynamic pressure difference of the battery cell and determines whether it is less than the threshold value U1. When the detected dynamic pressure difference of the battery cell is less than the threshold value U1, step S4 is executed; when the detected dynamic pressure difference of the battery cell is not less than the threshold value U1, step S5 is executed. The vehicle VCU detects the dynamic pressure difference of the battery cell and determines the change of the dynamic pressure difference of the battery cell, and selects the appropriate charging logic to charge the battery pack;

[0041] S3. During the battery charging process, the vehicle VCU detects the dynamic pressure difference of the battery cell and the number of charging cycles, and determines whether the dynamic pressure difference of the battery cell is greater than the threshold value U2 and whether the number of charging cycles cycle is greater than the threshold value N. When the dynamic pressure difference of the battery cell is greater than the threshold value U2 and the number of charging cycles cycle is greater than the threshold value N, step S6 is executed; when the dynamic pressure difference of the battery cell is not greater than the threshold value U2 or the number of charging cycles cycle is not greater than the threshold value N, step S7 is executed, the vehicle VCU detects the dynamic pressure difference of the battery cell and the number of charging cycles, and selects the appropriate charging logic to charge the battery pack;

[0042] S4, maintaining the original charging current MAP request logic of the battery system, and charging the battery pack with a constant current value I0;

[0043] S5. The vehicle VCU requests to output a constant-current charging current value I1. The BMS requests the current I0 and the constant-current charging current value I1 according to the charging current MAP, and outputs the final requested charging current value (I1, I0)min to charge the battery pack. The BMS requests the current I0 and the constant-current charging current value I1 according to the charging current MAP, and specifically, when I0>I1, the battery pack is charged with the constant-current charging current value I1 requested by the vehicle VCU; when I0<I1, the battery pack is charged with the current I0 requested by the BMS according to the charging current MAP;

[0044] S6, request the output of constant current charging current value I through the vehicle VCU 1i , BMS requests current I according to the charging current MAP 0i With constant current charging current value I 1i Take the smaller value and output the final requested charging current value (I 1i , I 0i )min, charge the battery pack. When I 1i Less than I 0i When the vehicle VCU requests a constant current charging current value I 1i Charge the battery pack; when I 1i Greater than I 0i When BMS requests current I according to charging current MAP 0i Charging the battery pack;

[0045] S7, BMS requests current I according to charging current MAP 0i , to request current I 0i Charge the battery pack.

[0046] In the step S1, the range of the monomer maximum voltage threshold C is (3.0V, 3.55V), the range of the threshold C is the constant current charging control stage, the range of the threshold D is (3.55V, 3.7V), and the range of the threshold D is the constant voltage charging control stage.

[0047] In the step S3, the cell dynamic voltage difference threshold U1 is 200mv.

[0048] In step S4, the dynamic voltage difference threshold U2 of the battery cell is 250mv, and the cycle number threshold N is 10 times.

[0049] During the battery charging process, the vehicle VCU detects the maximum voltage value of the battery cell, the dynamic voltage difference of the battery cell and the number of charging cycles. When the maximum voltage value of the battery cell is low, the original charging current MAP request logic of the battery system is maintained, and the battery pack is charged with a constant charging current to quickly charge the battery. When the maximum voltage value of the battery cell rises to a higher range during the fast charging process and when the dynamic voltage difference of the battery cell changes greatly and the number of charging cycles is large, the vehicle VCU requests the output of a constant charging current value that is smaller than the charging current MAP request current to charge the battery stably, reduce energy waste during charging, reduce battery damage during charging, and reduce the frequency of battery maintenance.

[0050] During the battery charging process from step S1 to step S7, I 1i and I 0iAs the battery cell voltage value changes in real time and outputs the minimum value to charge the battery pack, when the vehicle VCU detects that the voltage rise rate of the charging terminal cell exceeds threshold A or the voltage difference increase rate exceeds threshold B or I 0i The reduction rate exceeds the threshold E, where the threshold A is 0.06mv / s, the threshold B is 250mv, and the threshold E is 20A / s. The vehicle VCU actively intervenes to reduce the constant current charging current value I 1i , BMS requests current I according to the charging current MAP 0i The constant current charging current value I 1i Take the smaller value and output the final requested charging current value (I 1i , I 0i )min, charge the battery pack. When I 1i Less than I 0i When the vehicle VCU requests a constant current charging current value I 1i Charge the battery pack; when I 1i Greater than I 0i When BMS requests current I according to charging current MAP 0i Charge the battery pack.

[0051] When the vehicle VCU detects that the voltage rise rate of the battery cell at the charging end exceeds 0.06mv / s or the voltage difference increase rate exceeds 250mv or I 0i When the reduction rate exceeds 20A / s, the vehicle VCU actively intervenes to reduce the constant current charging current. The BMS charges the battery pack based on the smaller current requested by the charging current MAP and the constant current charging current value of the vehicle VCU, thereby achieving balanced maintenance of the battery charging end, improving the consistency of the battery cells, and increasing the service life of the power battery in long-cycle and multi-frequency charging and discharging scenarios.

[0052] The charging equalization maintenance method includes three charging modes, specifically:

[0053] (1) Mode 1: Charging control is performed based on the original charging current MAP of the battery system BMS, which is divided into a constant current charging control stage and a constant voltage charging control stage. The constant current charging control stage corresponds to Figure 2 In the A-B stage, the charging current is I0, and the constant voltage charging control stage corresponds to Figure 2 In the B-C stage, the charging current is I 0i , I 0i Corresponding to "Current 1 curve";

[0054] (2) Mode 2: In the constant voltage charging control stage, the BMS requests the current I according to the charging current MAP. 0i The constant current charging current value I 1i Take small control to charge the battery pack, and the constant voltage charging control stage corresponds to Figure 2 Upper B-C stage, the charging current corresponds to the "Current 2 curve";

[0055] (3) Mode 3: Full stage, BMS requests current I according to charging current MAP 0i The constant current charging current value I 1i Take small control to charge the battery pack, and the whole stage corresponds to Figure 2 In the A-B-C stage, the charging current corresponds to the "Current 3 Curve".

[0056] The vehicle VCU monitors the health status and consistency of the battery system cells in real time, switches the charging mode in real time, and optimizes the charging stage I 1i Without changing the original charging current MAP of the battery management system BMS, the charging maintenance balance of the battery health status is performed, and the charging time is extended to less than 20 minutes by reducing the terminal trickle charging current value. However, the charging mode used in the above charging method triggers the maintenance frequency estimated to be twice a week. Although this charging method reduces the charging rate of the power battery, it greatly saves the risk and cost of manual battery maintenance, and also improves the charging safety and service life of the battery. At the same time, in large-tonnage and large-capacity equipment, large-capacity power batteries must be matched, but large-capacity batteries often have the problem of high charging and low discharge during use, which affects the service life and charge of the power battery. Through the charging balance maintenance method of this application, the service life and duration of large-tonnage and large-capacity equipment are improved to meet the needs of long-term operation of the equipment.

[0057] The above-described embodiments only express a certain implementation mode of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A battery charging and equalization maintenance method for a pure electric wide-body dump truck, characterized in that: S1. During the battery charging process, the vehicle VCU detects the maximum voltage value of the battery cell and determines whether the current maximum voltage value of the cell is within the threshold C or threshold D. When the maximum voltage value of the cell is within the threshold C range, step S2 is executed; when the maximum voltage value of the cell is within the threshold D range, step S3 is executed; S2. During the battery charging process, the vehicle VCU detects the dynamic voltage difference of the battery cell and determines whether it is less than the threshold value U1. When the detected dynamic voltage difference of the battery cell is less than the threshold value U1, step S4 is executed; when the detected dynamic voltage difference of the battery cell is not less than the threshold value U1, step S5 is executed; S3. During the battery charging process, the vehicle VCU detects the dynamic voltage difference of the battery cell and the number of charging cycles, and determines whether the dynamic voltage difference of the battery cell is greater than the threshold value U2 and whether the number of charging cycles cycle is greater than the threshold value N. When the dynamic voltage difference of the battery cell is greater than the threshold value U2 and the number of charging cycles cycle is greater than the threshold value N, step S6 is executed; when the dynamic voltage difference of the battery cell is not greater than the threshold value U2 or the number of charging cycles cycle is not greater than the threshold value N, step S7 is executed; S4, maintaining the original charging current MAP request logic of the battery system, and charging the battery pack with a constant current value I0; S5. The vehicle VCU requests the output of a constant current charging current value I1. The BMS requests the current I0 based on the charging current MAP and takes the smaller value of the constant current charging current value I1, and outputs the final requested charging current value (I1, I0)min to charge the battery pack. S6, request the output of constant current charging current value I through the vehicle VCU 1i , BMS requests current I according to the charging current MAP 0i With constant current charging current value I 1i Take the smaller value and output the final requested charging current value (I 1i , I 0i )min, charge the battery pack; S7, BMS requests current I according to charging current MAP 0i , to request current I 0i Charge the battery pack.

2. A battery charge equalization maintenance method for a pure electric wide-body dump truck according to claim 1, characterized in that: During the battery charging process from step S1 to step S7, I 1i and I 0i As the battery cell voltage value changes in real time and outputs the minimum value to charge the battery pack, when the vehicle VCU detects that the voltage rise rate of the charging terminal cell exceeds threshold A or the voltage difference increase rate exceeds threshold B or I 0i When the reduction rate exceeds the threshold E, the vehicle VCU actively intervenes to reduce the constant current charging current value I 1i , BMS requests current I according to the charging current MAP 0i The constant current charging current value I 1i Take the smaller value and output the final requested charging current value (I 1i , I 0i )min, charge the battery pack.

3. A battery charge equalization maintenance method for a pure electric wide-body dump truck according to claim 2, characterized in that: The threshold A is 0.06 mv / s, the threshold B is 250 mv, and the threshold E is 20 A / s.

4. A battery charge equalization maintenance method for a pure electric wide-body dump truck according to claim 2, characterized in that: In the step S1, the range of the monomer maximum voltage threshold C is (3.0V, 3.55V), the range of the threshold C is the constant current charging control stage, the range of the threshold D is (3.55V, 3.7V), and the range of the threshold D is the constant voltage charging control stage.

5. A battery charge equalization maintenance method for a pure electric wide-body dump truck according to claim 2, characterized in that: In the step S3, the cell dynamic voltage difference threshold U1 is 200mv.

6. A battery charge equalization maintenance method for a pure electric wide-body dump truck according to claim 2, characterized in that: In the step S4, the battery cell dynamic voltage difference threshold U2 is 250mv, and the cycle number threshold N is 10 times.

7. A battery charge equalization maintenance method for a pure electric wide-body dump truck according to any one of claims 1 to 6, characterized in that: The charging equalization maintenance method includes three charging modes: (1) Mode 1: Charging control is performed with the original charging current MAP of the battery system BMS, which is divided into a constant current charging control stage and a constant voltage charging control stage. In the constant current charging control stage, the charging current is I0, and in the constant voltage charging control stage, the charging current is I 0i ; (2) Mode 2: In the constant voltage charging control stage, the BMS requests the current I according to the charging current MAP. 0i The constant current charging current value I 1i Take the small control to charge the battery pack; (3) Mode 3: Full stage, BMS requests current I according to charging current MAP 0i The constant current charging current value I 1i Take a small control and charge the battery pack.

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