1. A vehicle-mounted lithium battery charging method is characterized by comprising the following steps:

obtaining the current maximum charging current of the vehicle-mounted lithium battery according to the current electric quantity and the temperature of the vehicle-mounted lithium battery;

obtaining the maximum allowable charging current of the vehicle-mounted lithium battery according to the comparison result of the current maximum charging current and the output current of the charger;

and obtaining the target output current of the charger according to the voltage and the current of the vehicle-mounted lithium battery and the maximum allowable charging current, and controlling the charger to charge the vehicle-mounted lithium battery according to the target output current.

2. The method for charging the vehicle-mounted lithium battery as claimed in claim 1, wherein the current maximum charging current of the vehicle-mounted lithium battery is obtained by a SOP two-dimensional table look-up method according to the current electric quantity and the temperature of the vehicle-mounted lithium battery.

3. The method as claimed in claim 1, wherein the current maximum charging current is compared with the output current of the charger, and the smaller value is taken as the maximum allowable charging current of the vehicle lithium battery.

4. The method for charging the vehicle-mounted lithium battery as claimed in claim 1, wherein the vehicle-mounted lithium battery is charged in a current-limiting, constant voltage-current-limiting manner while the charger is controlled to charge the vehicle-mounted lithium battery according to the target output current.

5. The charging method of claim 4, wherein in the current-limiting-constant voltage-current-limiting mode, the current-limiting process of the first stage is to determine whether the highest voltage of the on-vehicle lithium battery reaches a constant current voltage, and if not, the charger is controlled to output a target output current; if the constant current voltage is reached, the constant voltage process of the first stage is started.

6. The method for charging a vehicle-mounted lithium battery as claimed in claim 4, wherein in the current-limiting-constant voltage-current-limiting mode, the constant voltage process of the first stage is to stabilize the maximum voltage of the vehicle-mounted lithium battery at a constant voltage by controlling the output current of the charger, and when the charging current drops to a set threshold, the current-limiting process of the third stage is entered.

7. The method as claimed in claim 4, wherein in the current-limiting-constant voltage-current-limiting mode, the current-limiting process in the third stage is to control the charger to keep the output current at the target output current until the vehicle-mounted lithium battery obtains the highest voltage setting value, thereby completing the charging.

8. A vehicle-mounted lithium battery charging system, comprising:

the maximum charging current determining module is configured to obtain the current maximum charging current of the vehicle-mounted lithium battery according to the current electric quantity and the temperature of the vehicle-mounted lithium battery;

the maximum allowable charging current determining module is configured to obtain the maximum allowable charging current of the vehicle-mounted lithium battery according to a comparison result of the current maximum charging current and the output current of the charger;

and the target output current determining module is configured to obtain a target output current of the charger according to the voltage and the current of the vehicle-mounted lithium battery and the maximum allowable charging current, and control the charger to charge the vehicle-mounted lithium battery according to the target output current.

9. An electronic device comprising a memory and a processor and computer instructions stored on the memory and executed on the processor, the computer instructions when executed by the processor performing the method of any of claims 1-7.

10. A computer-readable storage medium storing computer instructions which, when executed by a processor, perform the method of any one of claims 1 to 7.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

With the popularization of electric vehicles, the waste of public resources caused by the charging of the electric vehicles becomes an important factor for hindering the popularization of the electric vehicles, and based on the current situations of batteries and charging equipment of the electric vehicles, the charging speed is improved and the charging service life is shortened by optimizing a charging control method, so that the electric vehicle has important social value and economic value.

At present, two methods are mainly used for charging a vehicle-mounted lithium battery: firstly, multi-section current-limiting charging; the charging mode is simple to control, the requirement on the control precision of a charger is low, but the charging efficiency of the charging mode is low, and longer charging time is needed under the same charging capacity.

Secondly, the current-limiting charging is carried out at the front section, and the constant-voltage charging is carried out at the rear section; the mode can realize the maximization of the charging speed theoretically, but in the constant voltage stage, the problems that on one hand, the output current of a charger is unstable when the current is small, on the other hand, the response of the current change on the voltage level is increased due to the weakening of the receiving capacity of a battery in the last charging stage, the control in the last charging stage is unstable, and the charging time in the last charging stage is increased on the contrary; at the final stage of charging, due to the problem of control accuracy of a charger, charging current fluctuates, at the moment, the voltage of a battery exceeds the constant voltage requirement, a controller protectively stops charging, waits for the voltage to be lower than the constant voltage value, and then starts charging again, so that the charging is repeated, and the waste of charging time is caused.

Disclosure of Invention

In order to solve the problems, the invention provides a vehicle-mounted lithium battery charging method and a vehicle-mounted lithium battery charging system, wherein the charging current output to a vehicle-mounted lithium battery by a charger is controlled according to parameter information such as voltage, temperature, current, electric quantity and the like of the vehicle-mounted lithium battery, so that a current-limiting, constant-voltage-limiting charging mode is realized.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a vehicle-mounted lithium battery charging method, including:

obtaining the current maximum charging current of the vehicle-mounted lithium battery according to the current electric quantity and the temperature of the vehicle-mounted lithium battery;

obtaining the maximum allowable charging current of the vehicle-mounted lithium battery according to the comparison result of the current maximum charging current and the output current of the charger;

and obtaining the target output current of the charger according to the voltage and the current of the vehicle-mounted lithium battery and the maximum allowable charging current, and controlling the charger to charge the vehicle-mounted lithium battery according to the target output current.

As an alternative embodiment, the current maximum charging current of the vehicle-mounted lithium battery is obtained through an SOP two-dimensional table lookup method according to the current electric quantity and temperature of the vehicle-mounted lithium battery.

As an alternative embodiment, after comparing the current maximum charging current with the output current of the charger, the smaller value of the current maximum charging current and the output current of the charger is taken as the maximum allowable charging current of the vehicle-mounted lithium battery.

As an alternative embodiment, the vehicle-mounted lithium battery is charged in a current-limiting-constant voltage-current-limiting mode in the process of controlling the charger to charge the vehicle-mounted lithium battery according to the target output current.

As an alternative embodiment, in the current-limiting-constant voltage-current-limiting mode, the current-limiting process at the first stage is to judge whether the highest voltage of the vehicle-mounted lithium battery reaches the constant current voltage, and if the highest voltage of the vehicle-mounted lithium battery does not reach the constant current voltage, the charger is controlled to output a target output current; if the constant current voltage is reached, the constant voltage process of the first stage is started.

As an alternative embodiment, in the current-limiting-constant voltage-current-limiting mode, the constant voltage process in the first stage is to stabilize the maximum voltage of the on-vehicle lithium battery at a constant voltage by controlling the output current of the charger, and when the charging current drops to a set threshold, the current-limiting process in the third stage is entered.

As an alternative embodiment, in the current-limiting-constant voltage-current-limiting mode, the current-limiting process in the third stage is to control the charger to keep the output current as the target output current until the vehicle-mounted lithium battery obtains the highest voltage set value, and then the charging is completed.

In a second aspect, the present invention provides a vehicle-mounted lithium battery charging system, including:

the maximum charging current determining module is configured to obtain the current maximum charging current of the vehicle-mounted lithium battery according to the current electric quantity and the temperature of the vehicle-mounted lithium battery;

the maximum allowable charging current determining module is configured to obtain the maximum allowable charging current of the vehicle-mounted lithium battery according to a comparison result of the current maximum charging current and the output current of the charger;

and the target output current determining module is configured to obtain a target output current of the charger according to the voltage and the current of the vehicle-mounted lithium battery and the maximum allowable charging current, and control the charger to charge the vehicle-mounted lithium battery according to the target output current.

In a third aspect, the present invention provides an electronic device comprising a memory and a processor, and computer instructions stored on the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method of the first aspect is performed.

In a fourth aspect, the present invention provides a computer readable storage medium for storing computer instructions which, when executed by a processor, perform the method of the first aspect.

Compared with the prior art, the invention has the beneficial effects that:

the invention collects the parameter information of the vehicle-mounted lithium battery such as voltage, temperature, current, electric quantity and the like, and communicates with the charger through a communication line to control the output current of the charger and obtain the maximum power which can be output by the charger so as to control the charging current output by the charger to the vehicle-mounted lithium battery. The vehicle-mounted lithium battery is charged in a current-limiting, constant-voltage and current-limiting mode, and the optimal charging speed and the stability in the final charging stage at the initial charging stage and the middle charging stage are ensured.

Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a schematic diagram of a conventional multi-stage current-limiting charging method;

FIG. 2 is a schematic diagram of a conventional front-end current-limiting charging method and a rear-end constant-voltage charging method;

FIG. 3 is a schematic diagram of a conventional front-end current-limiting charging method and a rear-end constant-voltage charging method;

fig. 4 is a flowchart of a charging method for a vehicle-mounted lithium battery according to embodiment 1 of the present invention;

fig. 5 is a schematic diagram of three charging phases provided in embodiment 1 of the present invention;

fig. 6 is a schematic diagram of charging control in three charging phases provided in embodiment 1 of the present invention;

fig. 7 is a schematic diagram of a charging control process at stage T2 according to embodiment 1 of the present invention;

fig. 8 is a schematic view of a vehicle-mounted lithium battery charging system according to embodiment 1 of the present invention.

The specific implementation mode is as follows:

the invention is further described with reference to the following figures and examples.

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should be understood that the terms "comprises" and "comprising", and any variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

Example 1

As shown in fig. 1, a conventional multi-stage current-limiting charging method, such as the front-stage current-limiting charging method and the back-stage constant-voltage charging method shown in fig. 2, is prone to cause instability of control at the end of charging, and thus causes an increase in charging time at the end of charging, as shown in fig. 3.

Based on the problems in the prior art, the present embodiment provides a method for charging a vehicle-mounted lithium battery, as shown in fig. 4, including:

s1: obtaining the current maximum charging current of the vehicle-mounted lithium battery according to the current electric quantity and the temperature of the vehicle-mounted lithium battery;

s2: obtaining the maximum allowable charging current of the vehicle-mounted lithium battery according to the comparison result of the current maximum charging current and the output current of the charger;

s3: and obtaining the target output current of the charger according to the voltage and the current of the vehicle-mounted lithium battery and the maximum allowable charging current, and controlling the charger to charge the vehicle-mounted lithium battery according to the target output current.

In step S1, according to the current electric quantity and temperature of the on-vehicle lithium battery, the current maximum charging current I that the on-vehicle lithium battery can bear is obtained through the SOP two-dimensional table lookup method_bMAX；

Preferably, the SOP two-dimensional table is determined experimentally by the battery supplier, and a margin is retained.

In step S2, the present maximum charging current I of the on-vehicle lithium battery is set_bMAXAnd the maximum output current I of the charger_cMAXAfter comparison, a small value is taken to obtain the maximum allowable charging current I of the vehicle-mounted lithium battery_MAX；

Preferably, the maximum allowable charging current I_MAXThe maximum current value allowed by the battery and the charger is not more than the current value required by the charger in each stage in the charging process.

In step S3, a target output current I of the present charger is obtained according to the voltage, current and maximum allowable charging current of the on-vehicle lithium battery_cIn the embodiment, the vehicle-mounted lithium battery is charged in a current-limiting, constant-voltage and current-limiting mode, so that the optimal charging speed and charging in the initial charging stage and the intermediate charging stage are ensuredStability at the end stage, as shown in fig. 5, the charging process is divided into three stages, and the charging control process is shown in fig. 6;

at stage T1: detecting whether the highest voltage of the vehicle-mounted lithium battery reaches a constant current voltage V1, and if the highest voltage of the vehicle-mounted lithium battery does not reach the constant current voltage V1, controlling a charger to output the maximum chargeable current, namely the target output current I_c(ii) a If the constant current voltage V1 is reached, entering a stage T2;

in the period T1, the target output current of the charger is I_MAX。

At stage T2: the maximum voltage of the vehicle-mounted lithium battery is stabilized near constant current voltage V1 by controlling the output current of the charger, the charged electric quantity is gradually increased, the charging current is gradually reduced, and when the charging current is reduced to I₂When the program is executed, entering a T3 stage;

the T2 stage is a voltage closed-loop control stage, firstly, a target voltage difference value is obtained according to the current voltage and the target voltage of the vehicle-mounted lithium battery, PID adjustment is carried out according to the target voltage difference value and the current, and then the target voltage difference value and the current are subjected to the PID adjustment and the maximum allowable charging current I_MAXAnd comparing, taking the smaller value as the required current, and controlling the charger to output the current, as shown in fig. 7.

At stage T3: controlling the charger to keep the current as the maximum chargeable current I_cAnd finishing charging until the maximum voltage of the vehicle-mounted lithium battery reaches V3.

Example 2

As shown in fig. 8, the present embodiment provides an on-vehicle lithium battery charging system, including:

the maximum charging current determining module is configured to obtain the current maximum charging current of the vehicle-mounted lithium battery according to the current electric quantity and the temperature of the vehicle-mounted lithium battery;

the maximum allowable charging current determining module is configured to obtain the maximum allowable charging current of the vehicle-mounted lithium battery according to a comparison result of the current maximum charging current and the output current of the charger;

and the target output current determining module is configured to obtain a target output current of the charger according to the voltage and the current of the vehicle-mounted lithium battery and the maximum allowable charging current, and control the charger to charge the vehicle-mounted lithium battery according to the target output current.

In this embodiment, parameter information such as voltage, temperature, current, and electric quantity of the vehicle-mounted lithium battery is collected, and the parameter information is communicated with the charger through a communication line to control the output current of the charger, and obtain the maximum power that the charger can output, so as to control the charging current that the charger outputs to the vehicle-mounted lithium battery.

It should be noted that the modules correspond to the steps described in embodiment 1, and the modules are the same as the corresponding steps in the implementation examples and application scenarios, but are not limited to the disclosure in embodiment 1. It should be noted that the modules described above as part of a system may be implemented in a computer system such as a set of computer-executable instructions.

In further embodiments, there is also provided:

an electronic device comprising a memory and a processor and computer instructions stored on the memory and executed on the processor, the computer instructions when executed by the processor performing the method of embodiment 1. For brevity, no further description is provided herein.

It should be understood that in this embodiment, the processor may be a central processing unit CPU, and the processor may also be other general purpose processors, digital signal processors DSP, application specific integrated circuits ASIC, off-the-shelf programmable gate arrays FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and so on. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory may include both read-only memory and random access memory, and may provide instructions and data to the processor, and a portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information.

A computer readable storage medium storing computer instructions which, when executed by a processor, perform the method described in embodiment 1.

The method in embodiment 1 may be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor. The software modules may be located in ram, flash, rom, prom, or eprom, registers, among other storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor. To avoid repetition, it is not described in detail here.

Those of ordinary skill in the art will appreciate that the various illustrative elements, i.e., algorithm steps, described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.