Battery OCV-SOC curve calibration method and system and electric equipment

Abstract

The invention provides a battery OCV-SOC curve calibration method and system and electric equipment, and the method comprises the steps: enabling a user to operate an instrument to trigger an OCV-SOC curve calibration mode when the electric quantity of a battery is used up, enabling the instrument to prompt the user to be in a full electric quantity state, and recording the voltage of the full electric quantity state; in the use process of the battery, an ampere-hour integral method is used for calculating the collected voltage and the current accumulated discharge capacity in the process from the full electric quantity state to the electric quantity exhaustion; after the electric quantity of the battery is used up, constructing a voltage-capacity mapping relation according to the collected voltage and the current accumulated discharge quantity, obtaining the real-time residual capacity corresponding to each voltage, and converting the real-time residual capacity into a real-time SOC (State of Charge); and fitting the obtained discrete voltage and the real-time SOC to generate a new OCV-SOC curve. According to the scheme, a user does not need professional equipment or factory-returning maintenance, and self-calibration can be completed only through one-time complete charging and discharging riding.

Description

Technical Field

[0001] The present invention relates to the field of battery control technology, and in particular to a battery OCV-SOC curve calibration method, system and electric device. Background Art

[0002] When the current electric bicycle system does not communicate with the BMS (Battery Management System), the controller relies on a preset open circuit voltage (OCV) and state of charge (SOC, which is the percentage of the battery's remaining capacity to its full capacity) mapping curve to estimate the remaining battery capacity.

[0003] When users replace batteries with different types (ternary lithium, lithium iron phosphate, etc.) or with different full-capacity batteries, or when batteries age due to long-term use, or when the full-charge capacity of a battery changes due to seasonal temperature fluctuations, the preset curve deviates significantly from the actual battery curve, resulting in a large error in the SOC calculation. SOC is one of the most important parameters in an e-bike system, affecting the user's judgment of the remaining battery charge and the calculation of parameters such as the remaining range of the e-bike.

[0004] Existing technologies lack a user-defined calibration mechanism, requiring factory calibration with specialized equipment. This is costly and incapable of real-time adaptation to new batteries. Furthermore, relying solely on the ampere-hour integration method to calculate battery discharge can lead to cumulative errors due to inaccurate initial SOC benchmarks, further reducing the reliability of power estimation. Summary of the Invention

[0005] In view of the defects in the prior art, the purpose of the present invention is to provide a battery OCV-SOC curve calibration method, system and electric device.

[0006] A battery OCV-SOC curve calibration method provided by the present invention includes:

[0007] Calibration triggering steps: When the battery is exhausted, the user operates the meter to trigger the OCV-SOC curve calibration mode. The meter prompts the user to charge to full power and records the voltage at full power.

[0008] The steps for calculating the power benchmark are as follows: During the battery usage, the voltage and the current cumulative discharge capacity are calculated from the full charge state to the exhausted state using the ampere-hour integration method;

[0009] Real-time SOC conversion steps: After the battery is exhausted, a voltage-capacity mapping relationship is constructed based on the collected voltage and the current cumulative discharge amount to obtain the real-time remaining capacity corresponding to each voltage and convert it into real-time SOC;

[0010] Fitting step: The discrete voltage and real-time SOC are fitted to generate a new OCV-SOC curve.

[0011] Furthermore, in the calibration triggering step, the full charge state is determined by detecting that the voltage fluctuation amplitude is continuously less than a preset value within a preset time, and the battery is determined to be fully charged, and the full charge state voltage V is recorded. max , corresponding to SOC of 100%.

[0012] Furthermore, in the power reference calculation step, the current cumulative discharge capacity Where I is the current and Δt is the current discharge time.

[0013] Furthermore, in the power reference calculation step, when the battery voltage drops to the minimum voltage and lasts for a preset time, the battery is considered to be exhausted, and the battery exhaustion voltage V at this time is recorded. min , corresponding to SOC is 0%, the cumulative discharge amount C at this time real is the actual full charge capacity C act .

[0014] Furthermore, in the real-time SOC conversion step, the voltage-capacity mapping relationship includes:

[0015] Each voltage V i Corresponding to the actual remaining capacity C i , actual remaining capacity C i Equal to the actual full charge capacity C act Subtract the current accumulated discharge amount C real ,

[0016] Each voltage V i The corresponding real-time SOC is

[0017] A battery OCV-SOC curve calibration system provided by the present invention includes:

[0018] Calibration trigger module: When the battery is exhausted, the user operates the meter to trigger the OCV-SOC curve calibration mode. The meter prompts the user to charge to full power and records the voltage at full power.

[0019] Energy benchmark calculation module: During battery use, the ampere-hour integration method is used to calculate the collected voltage and current cumulative discharge capacity from the full power state to the exhausted power state;

[0020] Real-time SOC conversion module: After the battery is exhausted, a voltage-capacity mapping relationship is constructed based on the collected voltage and the current cumulative discharge amount to obtain the real-time remaining capacity corresponding to each voltage and convert it into real-time SOC;

[0021] Fitting module: The discrete voltage and real-time SOC are fitted to generate a new OCV-SOC curve.

[0022] Furthermore, in the calibration trigger module, the full charge state is determined by detecting that the voltage fluctuation amplitude is continuously less than a preset value within a preset time, and the battery is determined to be fully charged, and the full charge state voltage V is recorded. max , corresponding to SOC of 100%.

[0023] Furthermore, in the power reference calculation module, the current cumulative discharge capacity Where I is the current and Δt is the current discharge time;

[0024] When the battery voltage drops to the minimum voltage and lasts for a preset time, it is considered that the battery is exhausted, and the battery exhaustion voltage V is recorded at this time. min , corresponding to SOC is 0%, the cumulative discharge amount C at this time real is the actual full charge capacity C act .

[0025] Furthermore, in the real-time SOC conversion module, the voltage-capacity mapping relationship includes:

[0026] Each voltage V i Corresponding to the actual remaining capacity C i , actual remaining capacity C i Equal to the actual full charge capacity C act Subtract the current accumulated discharge amount C real ,

[0027] Each voltage V i The corresponding real-time SOC is

[0028] An electric device provided according to the present invention includes the battery OCV-SOC curve calibration system.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The solution in this invention eliminates the need for specialized equipment or factory repairs; a single full charge and discharge allows for self-calibration, seamlessly adapting to any third-party battery. The calibration process automatically updates the actual full-charge capacity, generating a new OCV-SOC curve. Simply monitoring voltage changes yields a more accurate SOC, enabling users to more accurately assess the remaining battery charge and calculate parameters such as the remaining range and remaining operating time of their electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0032] Figure 1 It is a working principle diagram of the present invention;

[0033] Figure 2 Schematic diagram of the battery OCV-SOC curve generated by the present invention. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0035] like Figure 1 As shown, the present invention provides a battery OCV-SOC curve calibration method, comprising:

[0036] Calibration triggering steps: When the battery is exhausted, the user operates the meter to trigger the OCV-SOC curve calibration mode. The meter prompts the user to charge to full power and records the full power state voltage.

[0037] The steps for calculating the power benchmark are as follows: During battery use, the ampere-hour integration method is used to calculate the voltage and current cumulative discharge capacity from the full power state to the exhausted power state.

[0038] Real-time SOC conversion steps: After the battery is exhausted, a voltage-capacity mapping relationship is constructed based on the collected voltage and the current cumulative discharge amount to obtain the real-time remaining capacity corresponding to each voltage and convert it into real-time SOC.

[0039] Fitting step: The discrete voltage and real-time SOC are fitted to generate a new OCV-SOC curve.

[0040] The present invention further provides a battery OCV-SOC curve calibration system, which can be implemented by executing the process steps of the battery OCV-SOC curve calibration method. That is, those skilled in the art can understand the battery OCV-SOC curve calibration method as a preferred embodiment of the battery OCV-SOC curve calibration system, and the system includes:

[0041] Calibration trigger module: When the battery is exhausted, the user operates the meter to trigger the OCV-SOC curve calibration mode. The meter prompts the user to charge to full capacity and records the voltage at full capacity.

[0042] Power benchmark calculation module: During battery use, the ampere-hour integration method is used to calculate the collected voltage and current cumulative discharge capacity from the full power state to the exhausted power state.

[0043] Real-time SOC conversion module: After the battery is exhausted, a voltage-capacity mapping relationship is constructed based on the collected voltage and the current cumulative discharge amount to obtain the real-time remaining capacity corresponding to each voltage and convert it into real-time SOC.

[0044] Fitting module: The discrete voltage and real-time SOC are fitted to generate a new OCV-SOC curve.

[0045] In one embodiment, the battery OCV-SOC curve calibration method is used to calibrate the OCV-SOC curve of an electric-assisted bicycle battery.

[0046] First, the user triggers the battery OCV-SOC curve calibration mode through the meter function in the electric bicycle system when the battery is completely exhausted (the vehicle cannot start). The user then charges the battery to full charge. After the controller detects that the voltage fluctuation is continuously less than 0.1V for 3 minutes, it records the full charge voltage V max (corresponding to SOC=100%, corresponding to the actual full charge capacity C act ).

[0047] Then, the user continues or intermittently rides until the battery can no longer discharge. During the ride, the controller monitors the discharge current in real time. At this time, the discharge current varies with the user's pedaling strength or speed. When the current is lower than 1A (the battery polarization effect can be ignored at this time, and the sampled voltage is the open circuit voltage), the open circuit voltage and the current cumulative discharge capacity C are synchronously collected. real (Calculated by the ampere-hour integration method, that is, the integral value of the current I over the current discharge time Δt, as shown in the formula ). When the battery voltage drops to the lowest voltage and lasts for 3 minutes, the discharge phase ends and the voltage V at this time is recorded. min (corresponding to SOC=0%), at this time the battery cumulative discharge capacity C real That is the actual full charge capacity C act , and use this as the battery power benchmark.

[0048] When the battery is fully discharged, the controller constructs a voltage-capacity mapping table based on all the collected data points, as shown in Table 1. i Corresponding real-time remaining capacity C i (ie actual full charge capacity C act Subtract the cumulative discharge capacity C at that moment real , as shown in the formula ), and then converted to real-time SOC i (i.e. remaining capacity C i / Actual full charge capacity C act ×100%, as shown in the formula ).

[0049]

[0050]

[0051] Table 1 Battery voltage-capacity mapping table

[0052] Finally, these discrete voltage and battery capacity data points are fitted to generate a new OCV-SOC curve, such as Figure 2 The controller has a preset curve. After calibration, the controller only needs to detect voltage changes to obtain a more accurate battery SOC.

[0053] In one embodiment, the battery OCV-SOC curve calibration system is used for calibrating the OCV-SOC curve of an electric-assisted bicycle battery.

[0054] Electric bicycle battery OCV-SOC curve calibration system, such as Figure 1 This system mainly consists of an electric bicycle instrument and controller, including the instrument and human-computer interaction unit. The controller part of the system is divided into a battery status detection module and a data calculation and storage module. The battery status detection module includes a voltage and current sampling unit and a battery status judgment unit. The data calculation and storage module includes a data storage unit, a battery capacity calculation unit, and a curve reconstruction unit.

[0055] First, when the battery is completely exhausted (the vehicle cannot start), the user triggers the battery OCV-SOC curve calibration mode through the instrument function (i.e., the human-computer interaction unit) in the electric bicycle system. The user then charges the battery to a full charge state. During this process, the controller voltage sampling unit samples the voltage in real time. When the controller battery status judgment unit detects that the battery voltage fluctuation is continuously less than 0.1V for 3 minutes, it determines that the battery is fully charged and records the full charge voltage V max (corresponding to SOC=100%, corresponding to the actual full charge capacity C act ) and stored in the data storage unit.

[0056] Then, the user rides continuously or intermittently until the battery can no longer discharge. During the riding process, the controller battery status monitoring module monitors the discharge current in real time. At this time, the discharge current varies with the user's pedaling strength or speed. The current sampling unit samples the discharge current in real time and stores it in the data storage unit. When the battery discharge current sampled by the current sampling unit is lower than 1A, the battery status judgment unit judges that the battery voltage sampled by the voltage sampling unit at this time is the open circuit voltage (the battery polarization effect can be ignored at this time, and the sampled voltage is the open circuit voltage). This voltage data is stored in the data storage unit. While obtaining the open circuit voltage, the battery capacity calculation unit can calculate the current cumulative discharge capacity C based on the real-time data of the battery discharge current stored in the above data storage unit. real (Calculated by the ampere-hour integration method, that is, the integral value of the current I over the current discharge time Δt, as shown in the formula ) and stores it in the data storage unit in a one-to-one correspondence with the open circuit voltage. When the battery voltage drops to the lowest voltage and lasts for 3 minutes, the battery status judgment unit determines that the battery discharge stage is terminated, and the voltage V is recorded at this time. min (corresponding to SOC = 0%) and stored in the data storage unit. At this time, the battery cumulative discharge capacity C real That is the actual full charge capacity C act , and stored in the data storage unit, the controller battery capacity calculation unit will be the actual full charge capacity C act Used as a battery charge benchmark for battery capacity calculations.

[0057] When the battery is fully discharged, the controller battery capacity calculation unit calculates the current accumulated discharge capacity C according to the open circuit voltage data points stored in the data storage unit. real The data points construct a voltage-capacity mapping table, as shown in Table 1. Each open circuit voltage V i Corresponding real-time remaining capacity C i (ie actual full charge capacity C act Subtract the cumulative discharge capacity C at that moment real , as shown in the formula ), and then converted to real-time SOC i (i.e. remaining capacity C i / Actual full charge capacity C act ×100%, as shown in the formula ).

[0058] Finally, the curve reconstruction unit fits these discrete voltage and battery capacity data points to generate a new OCV-SOC curve as shown in Figure 2 The controller stores the new OCV-SOC curve data in the data storage unit, overwriting the original preset curve for the controller to call. After calibration, the controller still only needs to detect voltage changes to obtain a more accurate battery SOC.

[0059] The present invention also provides an electric device, comprising the above-mentioned battery OCV-SOC curve calibration system, and the electric device may be an electric-assisted bicycle, an electric tool, etc.

[0060] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0061] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A battery OCV-SOC curve calibration method, characterized in that: include: Calibration triggering steps: When the battery is exhausted, the user operates the meter to trigger the OCV-SOC curve calibration mode. The meter prompts the user to charge to full power and records the voltage at full power. The steps for calculating the power benchmark are as follows: During the battery usage, the voltage and the current cumulative discharge capacity are calculated from the full charge state to the exhausted state using the ampere-hour integration method; Real-time SOC conversion steps: After the battery is exhausted, a voltage-capacity mapping relationship is constructed based on the collected voltage and the current cumulative discharge amount to obtain the real-time remaining capacity corresponding to each voltage and convert it into real-time SOC; Fitting step: The discrete voltage and real-time SOC are fitted to generate a new OCV-SOC curve.

2. The battery OCV-SOC curve calibration method according to claim 1, characterized in that: In the calibration triggering step, the full charge state is determined by detecting that the voltage fluctuation amplitude is continuously less than the preset value within the preset time, then the battery is determined to be fully charged, and the full charge state voltage V is recorded. max , corresponding to SOC of 100%.

3. The battery OCV-SOC curve calibration method according to claim 1, characterized in that: In the power reference calculation step, the current cumulative discharge capacity Where I is the current and Δt is the current discharge time.

4. The battery OCV-SOC curve calibration method according to claim 1, characterized in that: In the power reference calculation step, when the battery voltage drops to the minimum voltage and lasts for a preset time, the battery is considered to be exhausted, and the battery exhaustion voltage V at this time is recorded. min , corresponding to SOC is 0%, the cumulative discharge amount C at this time rcal is the actual full charge capacity C act .

5. The battery OCV-SOC curve calibration method according to claim 1, characterized in that: In the real-time SOC conversion step, the voltage-capacity mapping relationship includes: Each voltage V i Corresponding to the actual remaining capacity C i , actual remaining capacity C i Equal to the actual full charge capacity C act Subtract the current accumulated discharge amount C real , Each voltage V i The corresponding real-time SOC is 6. A battery OCV-SOC curve calibration system, characterized in that: include: Calibration trigger module: When the battery is exhausted, the user operates the meter to trigger the OCV-SOC curve calibration mode. The meter prompts the user to charge to full power and records the voltage at full power. Energy benchmark calculation module: During battery use, the ampere-hour integration method is used to calculate the collected voltage and current cumulative discharge capacity from the full power state to the exhausted power state; Real-time SOC conversion module: After the battery is exhausted, a voltage-capacity mapping relationship is constructed based on the collected voltage and the current cumulative discharge amount to obtain the real-time remaining capacity corresponding to each voltage and convert it into real-time SOC; Fitting module: The discrete voltage and real-time SOC are fitted to generate a new OCV-SOC curve.

7. The battery OCV-SOC curve calibration system according to claim 6, characterized in that: In the calibration trigger module, the full charge state is determined by detecting that the voltage fluctuation amplitude is continuously less than the preset value within the preset time, then the battery is determined to be fully charged, and the full charge state voltage V is recorded. max , corresponding to SOC of 100%.

8. The battery OCV-SOC curve calibration system according to claim 6, characterized in that: In the power reference calculation module, the current cumulative discharge capacity Where I is the current and Δt is the current discharge time; When the battery voltage drops to the minimum voltage and lasts for a preset time, it is considered that the battery is exhausted, and the battery exhaustion voltage V is recorded at this time. min , corresponding to SOC is 0%, the cumulative discharge amount C at this time real is the actual full charge capacity C act .

9. The battery OCV-SOC curve calibration system according to claim 6, characterized in that: In the real-time SOC conversion module, the voltage-capacity mapping relationship includes: Each voltage V i Corresponding to the actual remaining capacity C i , actual remaining capacity C i Equal to the actual full charge capacity C act Subtract the current accumulated discharge amount C real , Each voltage V i The corresponding real-time SOC is 10. An electric device, characterized in that: A battery OCV-SOC curve calibration system comprising the battery OCV-SOC curve calibration system according to any one of claims 6 to 9.

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