A battery pack active balancing system and method

Abstract

The present invention discloses a battery pack active balancing system and method, which relates to the field of battery technology. The system includes a battery pack, a main control module, and an active balancing module, wherein the main control module is used to monitor the status information of each single cell in the battery pack, calculate the equivalent SOC and the average equivalent SOC of each single cell according to the single cell status information, and generate a balancing instruction according to the equivalent SOC and the average equivalent SOC. The present invention can realize accurate detection of the single cell voltage and current of the battery pack by performing temperature compensation calculation on the detection value when detecting the single cell voltage and current of the battery pack according to the temperature unevenness of the battery pack, and further perform active balancing of the battery pack according to the calculated equivalent SOC and average equivalent SOC, thereby improving the rationality of the selection of the battery pack to be balanced and then improving the balancing efficiency of the battery pack.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery pack active balancing system and method. Background Art

[0002] The battery pack is one of the indispensable components of all kinds of modern electrical appliances. During the production process of single cells, the parameters of each single cell are kept completely consistent due to the limitations of equipment and other conditions. Therefore, after the battery pack is used many times, the voltage of each single cell often deviates. Therefore, in order to improve the efficiency of energy utilization and ensure the safety of battery pack use, the battery pack is often balanced during use.

[0003] Current balancing technologies can be divided into passive balancing and active balancing. For passive balancing, when it is determined that the cell voltages of some cells are significantly higher than those of other cells, the balancing circuit is turned on to discharge them and improve their consistency; for active balancing, when it is determined that the cell voltages of some cells are significantly lower than those of other cells, the balancing circuit is turned on to charge them and improve their consistency. As can be seen from the above, no matter which balancing method is used, most of the cell voltages of the battery are used to determine whether the cell needs to be balanced. Therefore, the accuracy of the cell voltage detection directly affects the accuracy of the balancing start-up. However, the existing technology often ignores the impact of temperature on voltage, resulting in poor balancing effect. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a battery pack active balancing system and method.

[0005] In a first aspect, a battery pack active balancing system includes:

[0006] A battery pack, wherein the battery pack is composed of a plurality of lithium batteries connected in series;

[0007] An active balancing module for performing a balancing operation on a battery pack, wherein the active balancing module is connected to the battery;

[0008] A main control module for monitoring the status information of each single cell in a battery pack, calculating the equivalent SOC and average equivalent SOC of each single cell according to the single cell status information, and generating a balancing instruction according to the equivalent SOC and average equivalent SOC; the main control module is connected to the active balancing module.

[0009] Preferably, the active balancing module comprises a transformer control device, a transformer, and a field effect transistor, and the active control module, the transformer control device, the transformer, the field effect transistor, and the battery pack are connected in sequence.

[0010] Preferably, the main control module includes:

[0011] A first calculation module, used for estimating an average equivalent SOC of the battery pack and an equivalent SOC of each single cell according to the state information of the battery pack;

[0012] The second judgment module is used to judge whether the difference between the equivalent SOC of each single battery and the average equivalent SOC is greater than or equal to a first threshold value,

[0013] The execution generation module generates a balancing instruction according to the judgment result.

[0014] Preferably, the first calculation module further includes:

[0015] A data acquisition unit, used to acquire status information of each single cell in the battery pack, wherein the status information includes current, voltage, and temperature;

[0016] The first judging unit is used to judge whether the temperature of the single battery is greater than a third threshold value.

[0017] The second judging unit is used to judge whether the temperature difference between the single cells is greater than a fourth threshold value.

[0018] The first calculation unit is used to perform a temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery.

[0019] The second calculation unit is used to perform a second type of temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery.

[0020] The third calculation unit is used to calculate the average equivalent SOC and the SOC of each single battery.

[0021] In a second aspect, a battery pack active balancing method comprises the following steps:

[0022] S1: Estimate the average equivalent SOC of the battery pack and the equivalent SOC of each single cell according to the state information of the battery pack;

[0023] S2: Determine whether the difference between the equivalent SOC of each single cell and the average equivalent SOC is greater than or equal to a first threshold value. If so, execute step S3; if not, end the balancing.

[0024] S3: Determine whether the equivalent SOC of the single battery is greater than a second threshold value, if so, execute step S4, if not, execute step S5;

[0025] S4: Generate an equalization instruction with equivalent SOC as the target equalization variable;

[0026] S5: Generate a balancing instruction with the equivalent voltage as the target balancing variable.

[0027] Preferably, the method for estimating the average equivalent SOC of the battery pack and the equivalent SOC of each single cell according to the state information of the battery pack comprises the following steps:

[0028] S101: Acquire status information of each single cell in a battery pack, wherein the status information includes current, voltage, and temperature;

[0029] S102: Determine whether the temperature of the single cell is greater than a third threshold value. If so, execute step S103; if not, take the current and voltage in step S101 as equivalent current and equivalent voltage, and execute step S106;

[0030] S103: Determine whether the temperature difference between the single cells is greater than a fourth threshold value, if so, execute step S104, if not, execute step S105;

[0031] S104: performing a temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery, and executing step S106;

[0032] S105: performing a second type of temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery, and executing step S106;

[0033] S106: Estimate the average equivalent SOC and the SOC of each single cell based on the equivalent voltage and the equivalent current.

[0034] The beneficial effects of the present invention are embodied in: BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0036] Figure 1 is a system block diagram of Embodiment 1 of the present invention;

[0037] Figure 2 This is a flow chart of Embodiment 2 of the present invention;

[0038] Figure 3 This is a specific flow chart of step S1 of embodiment 2 of the present invention.

[0039] Figure 4 This is a schematic diagram of the structure of the third embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0041] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0042] Embodiment 1

[0043] like Figure 1 As shown, an embodiment of the present invention provides a battery pack active balancing system, comprising:

[0044] A battery pack, wherein the battery pack is composed of a plurality of lithium batteries connected in series;

[0045] An active balancing module for performing a balancing operation on a battery pack, wherein the active balancing module is connected to the battery;

[0046] A main control module for monitoring the status information of each single cell in a battery pack, calculating the equivalent SOC and average equivalent SOC of each single cell according to the single cell status information, and generating a balancing instruction according to the equivalent SOC and average equivalent SOC; the main control module is connected to the active balancing module.

[0047] In this embodiment, the active balancing module includes a transformer control device, a transformer, and a field effect transistor, and the active control module, the transformer control device, the transformer, the field effect transistor, and the battery pack are connected in sequence. Specifically, the field effect transistor array is model IRF510S, which ensures that it can work stably during the battery charging and discharging process.

[0048] In this embodiment, the main control module includes:

[0049] A first calculation module, used for estimating an average equivalent SOC of the battery pack and an equivalent SOC of each single cell according to the state information of the battery pack;

[0050] The second judgment module is used to judge whether the difference between the equivalent SOC of each single battery and the average equivalent SOC is greater than or equal to a first threshold value,

[0051] The execution generation module generates a balancing instruction according to the judgment result.

[0052] Wherein, the first calculation module further includes:

[0053] A data acquisition unit, used to acquire status information of each single cell in the battery pack, wherein the status information includes current, voltage, and temperature;

[0054] The first judging unit is used to judge whether the temperature of the single battery is greater than a third threshold value.

[0055] The second judging unit is used to judge whether the temperature difference between the single cells is greater than a fourth threshold value.

[0056] The first calculation unit is used to perform a temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery.

[0057] The second calculation unit is used to perform a second type of temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery.

[0058] The third calculation unit is used to calculate the average equivalent SOC and the SOC of each single battery.

[0059] The specific working principle and its working process are as follows: the main control module monitors the status of each elevator battery in the battery pack, including temperature, voltage, and current at any time, determines whether to perform temperature compensation based on the temperature, and calculates the equivalent SOC and the average equivalent SOC based on the temperature compensation result, and generates a balancing strategy based on the equivalent SOC and the average equivalent SOC, so that the active balancing module can start the balancing operation according to the balancing strategy.

[0060] In summary, the active balancing method for battery packs provided by the present invention can realize accurate detection of the single cell voltage and current of the battery pack by performing temperature compensation calculation on the detection values ​​when detecting the single cell voltage and current of the battery pack according to the uneven temperature characteristics of the battery pack, and further actively balance the battery pack according to the calculated equivalent SOC and average equivalent SOC, thereby improving the rationality of the selection of the battery pack to be balanced and then improving the balancing efficiency of the battery pack, greatly reducing the balancing time of the battery pack, and also greatly reducing the heat caused by the balancing of the battery pack, extending the use time of the battery pack for one cycle, improving the consistency of the battery cells, and thus extending the service life of the battery pack.

[0061] Embodiment 2

[0062] like Figure 2 , 3 As shown, an embodiment of the present invention provides a battery pack active balancing method, comprising the following steps:

[0063] S1: Estimate the average equivalent SOC of the battery pack and the equivalent SOC of each single cell according to the state information of the battery pack;

[0064] S2: Determine whether the difference between the equivalent SOC of each single cell and the average equivalent SOC is greater than or equal to a first threshold value. If so, execute step S3; if not, end the balancing.

[0065] S3: Determine whether the equivalent SOC of the single battery is greater than a second threshold value, if so, execute step S4, if not, execute step S5;

[0066] S4: Generate an equalization instruction with equivalent SOC as the target equalization variable;

[0067] S5: Generate a balancing instruction with the equivalent voltage as the target balancing variable.

[0068] In this embodiment, the method for estimating the average equivalent SOC of the battery pack and the equivalent SOC of each single cell according to the state information of the battery pack includes the following steps:

[0069] S101: Acquire status information of each single cell in a battery pack, wherein the status information includes current, voltage, and temperature;

[0070] S102: Determine whether the temperature of the single cell is greater than a third threshold value. If so, execute step S103; if not, take the current and voltage in step S101 as equivalent current and equivalent voltage, and execute step S106;

[0071] S103: Determine whether the temperature difference between the single cells is greater than a fourth threshold value, if so, execute step S104, if not, execute step S105;

[0072] S104: performing a temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery, and executing step S106;

[0073] S105: performing a second type of temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery, and executing step S106;

[0074] S106: Estimate the average equivalent SOC and the SOC of each single cell based on the equivalent voltage and the equivalent current.

[0075] A battery pack active balancing method provided in an embodiment of the present invention and a battery pack active balancing system provided in the aforementioned embodiment are based on the same inventive concept. Therefore, regarding each step in this embodiment and the working process in this embodiment, reference can be made to the corresponding contents disclosed in the aforementioned embodiment, and no further details will be given here.

[0076] Embodiment 3

[0077] like Figure 3As shown, an embodiment of the present invention further provides a structural schematic diagram of an electronic device, which includes a processor, an input device, an output device and a memory, wherein the processor, input device, output device and memory are interconnected, the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the method described in the above second embodiment.

[0078] It should be understood that in the embodiments of the present invention, the processor referred to 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), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0079] Input devices may include a touchpad, a fingerprint sensor (for collecting the user's fingerprint information and fingerprint direction information), a microphone, etc., and output devices may include a display (LCD, etc.), a speaker, etc.

[0080] The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0081] In a specific implementation, the processor, input device, and output device described in the embodiments of the present invention may execute the implementation described in the method embodiment provided in the embodiments of the present invention, or may execute the implementation described in the system embodiment described in the embodiments of the present invention, which will not be described in detail here.

[0082] Embodiment 4

[0083] An embodiment of the present invention provides an embodiment of a computer-readable storage medium, wherein the computer storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the processor executes the method described in the above embodiment.

[0084] The computer-readable storage medium may be an internal storage unit of the terminal described in the foregoing embodiments, such as a hard disk or memory of the terminal. The computer-readable storage medium may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the terminal. Further, the computer-readable storage medium may also include both an internal storage unit of the terminal and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal. The computer-readable storage medium may also be used to temporarily store data that has been output or is to be output.

[0085] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0086] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the terminals and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here.

[0087] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A battery pack active balancing method, characterized in that: The following steps are involved: S1: Estimate the average equivalent SOC of the battery pack and the equivalent SOC of each single cell according to the state information of the battery pack; S2: Determine whether the difference between the equivalent SOC of each single cell and the average equivalent SOC is greater than or equal to a first threshold value. If so, execute step S3; if not, end the balancing. S3: Determine whether the equivalent SOC of the single battery is greater than a second threshold value, if so, execute step S4, if not, execute step S5; S4: Generate an equalization instruction with equivalent SOC as the target equalization variable; S5: Generate a balancing instruction with the equivalent voltage as the target balancing variable; In step S1, the method for estimating the average equivalent SOC of the battery pack and the equivalent SOC of each single cell according to the state information of the battery pack includes the following steps: S101: Acquire status information of each single cell in a battery pack, wherein the status information includes current, voltage, and temperature; S102: Determine whether the temperature of the single cell is greater than a third threshold value. If so, execute step S103; if not, take the current and voltage in step S101 as equivalent current and equivalent voltage, and execute step S106; S103: Determine whether the temperature difference between the single cells is greater than a fourth threshold value, if so, execute step S104, if not, execute step S105; S104: performing a temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery, and executing step S106; S105: performing a second type of temperature compensation calculation based on the voltage, current and temperature to calculate the equivalent current and equivalent voltage of each single battery, and executing step S106; S106: Estimate the average equivalent SOC and the SOC of each single cell based on the equivalent voltage and the equivalent current.

2. A battery pack active balancing system, characterized in that: Includes the following: A battery pack, wherein the battery pack is composed of a plurality of lithium batteries connected in series; An active balancing module for performing a balancing operation on a battery pack, wherein the active balancing module is connected to the battery; A main control module for monitoring the status information of each single cell in the battery pack, calculating the equivalent SOC and the average equivalent SOC of each single cell according to the single cell status information, and generating a balancing instruction according to the equivalent SOC and the average equivalent SOC; The main control module is connected to the active balancing module; The main control module comprises: A first calculation module, used for estimating an average equivalent SOC of the battery pack and an equivalent SOC of each single cell according to the state information of the battery pack; The second judgment module is used to judge whether the difference between the equivalent SOC of each single battery and the average equivalent SOC is greater than or equal to a first threshold value, The execution generation module generates a balancing instruction according to the judgment result; The first calculation module also includes: A data acquisition unit, used to acquire status information of each single cell in the battery pack, wherein the status information includes current, voltage, and temperature; A first judging unit, used to judge whether the temperature of the single battery is greater than a third threshold; A second judging unit, used to judge whether the temperature difference between the single cells is greater than a fourth threshold; A first calculation unit, configured to perform a temperature compensation calculation based on the voltage, current and temperature to calculate an equivalent current and an equivalent voltage of each single battery; A second calculation unit, configured to perform a second type of temperature compensation calculation based on the voltage, current and temperature to calculate an equivalent current and an equivalent voltage of each single cell; A third calculation unit is used to calculate the average equivalent SOC and the SOC of each single battery; Determining whether to perform temperature compensation according to the temperature, calculating an equivalent SOC and an average equivalent SOC according to the temperature compensation result, and generating a balancing strategy according to the equivalent SOC and the average equivalent SOC; The main control module executes the battery pack active balancing method as claimed in claim 1.

3. The active equalization system for a battery pack according to claim 2, characterized in that: The active balancing module comprises a transformer control device, a transformer, and a field effect transistor. The main control module, the transformer control device, the transformer, the field effect transistor, and the battery pack are connected in sequence.

Images