Passive balancing method for a battery in a charged state

Abstract

The application discloses a passive equalization method of a battery in a charging state, and relates to the technical field of software function algorithm of vehicle power battery. The method comprises the following steps: data acquisition, data identification, data judgment and program control. The data acquisition method comprises the following steps: collecting the single battery voltage, the hardware board temperature and the lead-acid battery voltage in real time. Through the data, it can be judged whether the current battery state can be equalized. The data identification method comprises the following steps: obtaining the maximum value, the minimum value, the average value and the pressure difference between the highest single battery and the lowest single battery of the single battery voltage collected in real time. The single battery voltage is looked up from high to low to obtain the equalization SOC value corresponding to each single battery. The application can keep the lithium ion battery single battery voltage or the battery pack voltage deviation in the expected range, thereby ensuring that each single battery maintains the same state in the normal use, and avoiding overcharging and overdischarging.

Description

A passive balancing method for batteries in the charging state Technical Field

[0001] This invention relates to the field of software function algorithm technology for automotive power batteries, and in particular to a passive balancing method for batteries in the charging state. Background Technology

[0002] In recent years, more and more products have adopted lithium-ion batteries as their main power source, mainly because lithium-ion batteries have advantages such as small size, high energy density, no memory effect, long cycle life, and low self-discharge rate. However, lithium-ion batteries also have very high requirements for charging and discharging. When overcharging, over-discharging, overcurrent, or short circuits occur, the pressure and heat of the lithium-ion battery increase significantly, which can easily cause safety problems such as sparks, combustion, or even explosion, affecting the customer's user experience.

[0003] The design of this invention is to keep the voltage deviation of a single lithium-ion battery cell or the battery pack within a expected range, thereby ensuring that each single cell remains in the same state during normal use and avoiding overcharging and over-discharging. Summary of the Invention

[0004] The purpose of this invention is to provide a passive balancing method for batteries in the charging state, which can solve the problem that when lithium-ion batteries are overcharged, over-discharged, over-current, or short-circuited, the pressure and heat of the lithium-ion battery increase significantly, which can easily lead to sparks, combustion, or even explosion.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a passive equalization method for a battery in a charging state, comprising:

[0006] S1, Data Acquisition;

[0007] S2, Data Recognition;

[0008] S3, State transition;

[0009] S4, Program Control.

[0010] Preferably, the data acquisition method includes: real-time acquisition of individual cell voltage, hardware board temperature, and lead-acid battery voltage. These data can be used to determine whether the current battery state can be balanced.

[0011] Preferably, the data identification method includes: obtaining the maximum, minimum, and average values ​​of the real-time collected individual cell voltages, as well as the voltage difference between the highest and lowest individual cells; looking up the individual cell voltages in a table from high to low to obtain the equalization SOC value corresponding to each individual cell; then subtracting the equalization SOC value of the first ten individual cells from the lowest SOC value, and calculating the battery capacity and equalization resistance to determine the time required for equalization.

[0012] Preferably, the state transition method includes: when the lead-acid battery voltage is within the voltage range specified in the battery power supply in the datasheet, and the maximum hardware board temperature is below the upper limit, comparing the average single-cell voltage obtained by real-time processing of the collected single-cell voltage with the equalization average single-cell voltage threshold; when the collected average single-cell voltage is greater than the equalization average single-cell voltage threshold, equalization is activated; when the lead-acid battery voltage is below or above the lower limit, and the maximum board temperature is above the upper limit of the board temperature, equalization fault state is activated; when the fault state is not met and the average single-cell voltage is less than the equalization average voltage threshold, equalization is deactivated.

[0013] Preferably, the program control method includes: when equalization is enabled, the voltage of each cell that is being equalized is subtracted from the lowest cell voltage obtained in real time to obtain the equalization cell voltage difference; when the equalization cell voltage difference is greater than the equalization cell voltage difference threshold, equalization is continuously enabled for that cell; when the equalization cell voltage difference is less than or equal to the equalization cell voltage difference threshold, equalization for that cell is disabled; when the number of cells that are disabled for equalization has not reached the number of cells that are enabled for equalization, the equalization state remains enabled, and adjacent cells cannot be equalized simultaneously; only 10 cells can be equalized at a time.

[0014] Compared with the prior art, the beneficial effects of the present invention are: it can keep the voltage deviation of a single lithium-ion battery cell or the voltage of a battery pack within the expected range, thereby ensuring that each single battery cell remains in the same state during normal use, so as to avoid overcharging and over-discharging. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0016] Figure 1 is a schematic diagram of the equilibrium method framework of the present invention;

[0017] Figure 2 is a schematic diagram of data acquisition according to the present invention;

[0018] Figure 3 is a schematic diagram of data judgment according to the present invention;

[0019] Figure 4 is a schematic diagram of the state transition of the present invention;

[0020] Figure 5 is a schematic diagram of the program control of the present invention. Detailed Implementation

[0021] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] In the description of this invention, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0025] Please refer to Figures 1-5. The present invention provides a technical solution: a passive equalization method for a battery in a charging state, including data acquisition, data identification, state transition and program control.

[0026] Data acquisition methods include: real-time collection of individual cell voltage, hardware board temperature, and lead-acid battery voltage. These data can be used to determine whether the current battery state can be balanced.

[0027] The data identification method includes: obtaining the maximum, minimum, and average values ​​of the real-time collected individual cell voltages, as well as the voltage difference between the highest and lowest individual cells; looking up the individual cell voltages in a table from high to low to obtain the corresponding equalization SOC value for each individual cell; then, subtracting the equalization SOC value of the first ten individual cells from the lowest SOC value, and taking the battery capacity and equalization resistance to determine the time required for equalization.

[0028] The state transition method includes: when the lead-acid battery voltage is within the voltage range specified in the datasheet and the maximum hardware board temperature is below the upper limit, the average single-cell voltage obtained by real-time processing of the collected single-cell voltage is compared with the equalization average single-cell voltage threshold. When the collected average single-cell voltage is greater than the equalization average single-cell voltage threshold, equalization is activated. When the lead-acid battery voltage is below or above the lower limit and the maximum board temperature is above the upper limit of the board temperature, equalization fault state is activated. When the fault state is not met and the average single-cell voltage is less than the equalization average voltage threshold, equalization is deactivated.

[0029] The program control method includes: when equalization is turned on, the voltage of each cell that is equalized is subtracted from the lowest cell voltage obtained in real time to obtain the equalization cell voltage difference. When the equalization cell voltage difference is greater than the equalization cell voltage difference threshold, equalization is continuously turned on for that cell. When the equalization cell voltage difference is less than or equal to the equalization cell voltage difference threshold, equalization for that cell is turned off. When the number of cells that are turned off does not reach the number of cells that are turned on for equalization, the equalization state is always on. At the same time, adjacent cells cannot be equalized at the same time, and only 10 cells can be equalized at a time.

[0030] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A passive equalization method for batteries in a charging state, characterized in that, include: S1, Data Acquisition; S2, Data Recognition; S3, State transition; S4, Program Control; The data acquisition method includes: real-time acquisition of individual cell voltage, hardware board temperature, and lead-acid battery voltage; using this data to determine whether the current battery state can be balanced. The data identification method includes: deriving the maximum, minimum, and average values ​​of the real-time acquired individual cell voltages, as well as the voltage difference between the highest and lowest-voltage cells; looking up the individual cell voltages in a table from high to low to obtain the corresponding balanced SOC value for each cell; then subtracting the balanced SOC value of the first ten cells from the lowest SOC value, and calculating the battery capacity and balancing resistance to determine the required balancing time. The state transition method includes: when the lead-acid battery voltage is within the voltage range specified in the datasheet, and the maximum hardware board temperature is below the upper limit, comparing the average individual cell voltage obtained from the real-time acquisition of individual cell voltages with the balanced average individual cell voltage threshold; when the acquired average individual cell voltage... When the voltage exceeds the average cell voltage threshold, balancing is initiated. When the lead-acid battery voltage is below the lower limit or above the upper limit, or the highest plate temperature is above the upper limit plate temperature, a balancing fault state is initiated. When the fault state is not met and the average cell voltage is below the average cell voltage threshold, balancing is deactivated. The program control method includes: when balancing is initiated, the voltage of each cell in balancing is subtracted from the lowest real-time cell voltage to obtain the balancing cell voltage difference. When the balancing cell voltage difference is greater than the balancing cell voltage difference threshold, balancing for that cell continues to be initiated. When the balancing cell voltage difference is less than or equal to the balancing cell voltage difference threshold, balancing for that cell is deactivated. When the number of cells deactivated for balancing does not reach the number of cells in balancing for balancing, the balancing state remains active. Adjacent cells cannot be balanced simultaneously; only balancing of 10 cells can be initiated at a time.

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