Method for determining full charge of rechargeable battery, and charging apparatus

Abstract

A method for determining full charge of a rechargeable battery, and a charging apparatus, relating to the technical field of battery charging apparatuses. The method comprises: acquiring an initial battery voltage of a rechargeable battery at a first initial time in a charging process; after a first preset time interval, acquiring a current battery voltage of the rechargeable battery at a first current time in the charging process; subtracting the initial battery voltage from the current battery voltage to determine a battery voltage difference; updating the current battery voltage to be the initial battery voltage, and continuing to obtain a current battery voltage so as to update the battery voltage difference; and acquiring the number of times of the battery voltage differences being consecutively greater than a preset voltage difference, and, when the number of times is greater than or equal to a preset number of times, determining that the rechargeable battery is full in terms of battery level. The present application uses the battery voltage differences and the number of times of changing to determine whether the battery is fully charged, so as to control the surface temperature of the rechargeable battery, solving the problem of serious heating of rechargeable batteries during large-current charging, thus improving charging safety.

Description

A method for judging fullness of a rechargeable battery and a charging device Technical Field

[0001] The present invention relates to the technical field of battery charging devices, and in particular to a method for determining fullness of a rechargeable battery and a charging device. Background Art

[0002] Currently, the charging management methods used by nickel-metal hydride battery chargers on the market generally fall into the following categories: The first is timed charging, which offers low charging current, long charging time, and low cost, but is only feasible for nickel-metal hydride batteries of a certain capacity. As the number of cycles of a nickel-metal hydride battery increases, its capacity decays, which is equivalent to using the same charging time as a high-capacity battery to charge a low-capacity battery. This leaves the nickel-metal hydride battery in a state of overcharge for extended periods. Furthermore, most timed chargers use a unified multi-slot timing system, meaning that even the last battery added to the charger will be deemed fully charged as soon as the timer expires, leading to significant misjudgments. Therefore, this timed charging method is only marginally applicable to situations where batteries of a fixed capacity are simultaneously placed in the charger for charging. Existing technologies have improved this method, such as single-slot timing, but this only addresses the issue of inconsistent placement of batteries.

[0003] The second method is the currently mainstream 0ΔV or -ΔV fullness detection method. This method is widely considered an intelligent fullness detection algorithm for NiMH batteries and enables high-current charging. Because the batteries are independently charged, they are not differentiated by capacity or the time of placement in the charger. However, when the battery shows 0ΔV or -ΔV, it typically takes a while for the voltage to remain constant or decrease after it is fully charged. This negative voltage is typically 3-5mV, a very small change, which requires significant PCB layout, power supply, and signal processing challenges. Line interference or strong external magnetic or electric fields can easily overwhelm this weak signal, leaving the battery fullness determination based solely on a prolonged period of constant battery voltage. Consequently, the battery can remain overcharged for relatively long periods. Furthermore, due to the relatively high charging current, the battery surface temperature can be very high at the time of fullness detection. Poor hardware and software design can easily lead to undercharging or severe overcharging, resulting in significant overheating and shortened battery cycle life.

[0004] In addition to the currently mainstream 0ΔV and -ΔV fullness detection methods, some methods use the battery's surface temperature to detect fullness, or combine temperature with the 0ΔV and -ΔV methods. However, this method is costly to implement. Many chargers generate considerable heat during operation. If the temperature probe resistor is located at the electrode position (indirectly detecting the battery temperature through contact with the electrode), this method may obscure the battery's own temperature if the circuit board itself is very hot, leading to false detection. A better approach is to install a temperature sensor under the battery slot. This method is costly and complex to assemble. If the battery and the sensor are in good contact, it can accurately detect the battery temperature. However, inconsistent battery sizes often result in poor contact, leading to large detection errors. Technical issues

[0005] The main technical problem solved by the present invention is to provide a more accurate and low-cost method for judging the fullness of a rechargeable battery and a charging device. Technical Solutions

[0006] According to the first aspect, an embodiment provides a method for determining fullness of a rechargeable battery, comprising:

[0007] Obtaining an initial battery voltage of the rechargeable battery at a first initial time during a charging process;

[0008] After a first preset time interval, obtaining a current battery voltage of the rechargeable battery at a first current time during the charging process;

[0009] Subtracting the initial battery voltage from the current battery voltage to determine a battery voltage difference; updating the current battery voltage to the initial battery voltage, and continuing to obtain the current battery voltage to update the battery voltage difference;

[0010] The number of times that the battery voltage difference is continuously greater than a preset voltage difference is obtained. When the number is greater than or equal to the preset number, the rechargeable battery is saturated.

[0011] In one embodiment, the obtaining of the number of times that the battery voltage difference is continuously greater than a preset voltage difference, and when the number is greater than or equal to the preset number, the rechargeable battery is saturated, includes:

[0012] The last battery voltage difference value among the times is obtained. When the times are greater than or equal to a preset number and the last battery voltage difference value is less than a first preset difference value, the rechargeable battery is saturated.

[0013] In one embodiment, obtaining the initial battery voltage of the rechargeable battery at a first initial time during the charging process includes:

[0014] Obtaining a charging curve of the rechargeable battery;

[0015] The time during which the slope of the charging curve is greater than the preset slope is defined as the first initial time.

[0016] In one embodiment, the method for determining whether a rechargeable battery is full further includes:

[0017] When the number is less than the preset number, the power level of the rechargeable battery is determined according to the battery voltage difference, wherein when the battery voltage difference is less than a second preset difference, the power level of the rechargeable battery is saturated.

[0018] In one embodiment, the method for determining whether a rechargeable battery is full further includes:

[0019] Obtaining an initial battery temperature of the rechargeable battery at a second initial time during the charging process;

[0020] After a second preset time interval, obtaining a current battery temperature of the rechargeable battery at a second current time during the charging process;

[0021] Subtracting the initial battery temperature from the current battery temperature to determine a battery temperature difference; updating the current battery temperature to the initial battery temperature, and continuing to obtain the current battery temperature to update the battery temperature difference;

[0022] The number of times that the battery temperature difference is continuously greater than the preset temperature difference is obtained. When the number of temperature differences is greater than or equal to the preset number of temperature differences, the rechargeable battery is saturated.

[0023] According to a second aspect, an embodiment provides a charging device, comprising:

[0024] A timing module, configured to set a first preset time interval;

[0025] a voltage acquisition module, connected to the timing module, for acquiring an initial battery voltage of the rechargeable battery at a first initial time during the charging process, and acquiring a current battery voltage of the rechargeable battery at a first current time during the charging process after a first preset time interval;

[0026] A data processing module is connected to the timing module and the voltage acquisition module, and is used to subtract the initial battery voltage from the current battery voltage to determine the battery voltage difference; update the current battery voltage to the initial battery voltage, and control the voltage acquisition module to continue to obtain the current battery voltage; the data processing module obtains the number of times the battery voltage difference is continuously greater than a preset voltage difference. When the number is greater than the preset number, the rechargeable battery is saturated.

[0027] In one embodiment, the data processing module obtains the number of times the battery voltage difference is continuously greater than a preset voltage difference, and when the number is greater than the preset number, the rechargeable battery is saturated, including:

[0028] The data processing module obtains the last battery voltage difference among the times. When the times are greater than or equal to a preset number and the last battery voltage difference is less than a first preset difference, the rechargeable battery is saturated.

[0029] In one embodiment, obtaining the initial battery voltage of the rechargeable battery at a first initial time during the charging process includes:

[0030] The data processing module obtains the charging curve of the rechargeable battery;

[0031] The time during which the slope of the charging curve is greater than the preset slope is defined as the first initial time.

[0032] In one embodiment, when the data processing module determines that the number of times is less than a preset number, the data processing module determines the power of the rechargeable battery based on the battery voltage difference, wherein when the battery voltage difference is less than a second preset difference, the power of the rechargeable battery is saturated.

[0033] In one embodiment, the charging device further includes a temperature acquisition module;

[0034] The temperature acquisition module acquires the initial battery temperature of the rechargeable battery at the second initial time during the charging process. After a second preset time interval set by the timing module, the temperature acquisition module further acquires the current battery temperature of the rechargeable battery at the second current time during the charging process. The data processing module subtracts the initial battery temperature from the current battery temperature to determine a battery temperature difference. The current battery temperature is updated to the initial battery temperature, and the current battery temperature is continuously acquired to update the battery temperature difference. The number of temperature differences during which the battery temperature difference is continuously greater than a preset temperature difference is acquired. When the number of temperature differences is greater than or equal to the preset number of temperature differences, the rechargeable battery is saturated. Beneficial effects

[0035] According to the above embodiment, a method for judging full charge of a rechargeable battery and a charging device, the method includes: obtaining the initial battery voltage of the rechargeable battery, obtaining the current battery voltage of the rechargeable battery after a first preset time interval, and subtracting the initial battery voltage from the current battery voltage to determine the battery voltage difference. At the same time, the current battery voltage is updated to the initial battery voltage, and the current battery voltage is continued to be obtained to update the battery voltage difference. The number of times the battery voltage difference is greater than the preset voltage difference is obtained, and when the number is greater than or equal to the preset number, the rechargeable battery is saturated. The present application uses the battery voltage difference and the number of changes to determine whether the battery is fully charged, thereby controlling the surface temperature of the rechargeable battery and solving the problem of severe heating of the rechargeable battery during high current charging. At the same time, it can also effectively extend the battery cycle life and improve the safety of charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a charging curve of a 2500mAh NiMH battery at 1.0A;

[0037] FIG2 is a flow chart of a method for determining fullness of a rechargeable battery according to an embodiment;

[0038] FIG3 is a second flow chart of a method for determining fullness of a rechargeable battery according to an embodiment;

[0039] FIG4 is a schematic diagram of a charging device according to another embodiment;

[0040] FIG5 is a graph showing the battery temperature, battery voltage, and ambient temperature of a certain brand of 2500mAh battery at a current of 1.0A according to a specific embodiment. Modes for Carrying Out the Invention

[0041] The present invention will be further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions, and for those skilled in the art, it is not necessary to describe these related operations in detail. They will fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0042] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0043] Component numbers used herein, such as "first" and "second," are used solely to distinguish the components being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings).

[0044] Please refer to Figure 1, which shows the charging curve for a 2500mAh NiMH battery at 1.0A. As shown in Figure 1, as charging time increases, the battery voltage changes significantly before the end of charging. From 2.1 hours to 2.6 hours, the difference in battery voltage change is greater than that before 2.1 hours. At 2.65 hours, the battery is fully charged, and the battery surface temperature is relatively low, within an acceptable range. At 2.6 hours, the battery is relatively saturated, and the surface temperature is even lower. After 2.65 hours or 2.7 hours, the energy charged into the battery is converted into heat and dissipated outward from the battery. At this point, the longer the charging time, the higher the battery surface temperature, eventually reaching a stable value. The current 0ΔV, -ΔV full charge judgment method is generated about half an hour after 2.65 hours or 2.7 hours. Therefore, if the charging current is large, such as 1A charging, and the 0ΔV, -ΔV full charge judgment method is used for full charge judgment, the battery surface temperature will be very hot, which will shorten the battery cycle life and burn the battery casing or other objects such as the charger casing. It is also easy to get hot, thus affecting the user experience.

[0045] This application uses the amount and number of battery voltage changes to determine whether the battery is fully charged. If it is determined to be fully charged, charging is stopped, thereby controlling the battery surface temperature and solving the problem of severe battery heating during high-current charging. It can also effectively extend the battery cycle life and improve charging safety. The following is a detailed explanation.

[0046] Referring to FIG. 2 , an embodiment provides a method for determining whether a rechargeable battery is full, including the following steps.

[0047] Step S110: obtaining an initial battery voltage of the rechargeable battery at a first initial time during the charging process.

[0048] In one embodiment, when obtaining the initial battery voltage of the rechargeable battery at the first initial time during the charging process, it is necessary to determine the specific value of the first initial time. Based on the rechargeable battery calibrated by engineering practice or experiment and the charging process of charging the rechargeable battery, the charging curve of the rechargeable battery can be obtained. According to the analysis of the charging curve of the rechargeable battery, the slope in the second half of the charging curve will be significantly larger. Therefore, the time point when the slope begins to be greater than the preset slope in the entire charging curve is set as the first initial time, and the initial battery voltage of the rechargeable battery at the first initial time is obtained. In one embodiment, the charging process refers to the entire charging process of the rechargeable battery, but there may be current and no current during the charging process. Therefore, as long as there is current or no current during the entire charging process of the battery, it belongs to the charging process. In one embodiment, the rechargeable battery is a nickel-metal hydride battery.

[0049] Step S120: obtaining the current battery voltage of the rechargeable battery at the first current time during the charging process.

[0050] In one embodiment, the time after the first preset time interval from the first initial time is the first current time, and the current battery voltage of the rechargeable battery at the first current time during the charging process is obtained.

[0051] Step S130: Subtract the initial battery voltage from the current battery voltage to determine a battery voltage difference.

[0052] In one embodiment, when the initial battery voltage and the current battery voltage are obtained in steps S110 and S120, respectively, the initial battery voltage is subtracted from the current battery voltage to determine the battery voltage difference. Simultaneously, the current battery voltage is updated to the initial battery voltage. The current battery voltage after a first preset time interval is then obtained, and the battery voltage difference is recalculated based on the newly obtained current battery voltage and the updated initial battery voltage to update the battery voltage difference. Steps S120 to S130 are repeated to continuously obtain updated battery voltage differences.

[0053] Step S140: Obtain the number of times that the battery voltage difference is continuously greater than a preset voltage difference. When the number is greater than or equal to the preset number, the rechargeable battery is saturated.

[0054] In one embodiment, the obtained battery voltage difference is compared with a preset voltage difference, and the number of times the battery voltage difference is continuously greater than the preset voltage difference is obtained. If the number is greater than or equal to the preset number, it indicates that the rechargeable battery is fully charged and saturated. At this time, according to the actual project situation, the rechargeable battery may be powered off or trickle-charged.

[0055] In one embodiment, when executing step S140, when determining the number of times the battery voltage difference is greater than the preset voltage difference, the last battery voltage difference among the number of times is also obtained. If the number of times is greater than the preset number and the last battery voltage difference is less than the first preset difference, it can also indicate that the rechargeable battery is fully charged and saturated. At this time, according to the actual project situation, the rechargeable battery may be powered off or trickle-charged.

[0056] 3 , a method for determining whether a rechargeable battery is full of charge provided in one embodiment further includes step S150 : when the number of times is less than a preset number, determining the charge level of the rechargeable battery according to the battery voltage difference.

[0057] In one embodiment, if the number of times the battery voltage difference obtained in step S140 is continuously greater than a preset voltage difference is always less than the preset number during the battery charging process, the battery voltage difference is used to determine whether the rechargeable battery is saturated. That is, when the battery voltage difference is less than a second preset difference, the rechargeable battery is saturated. At this time, depending on the actual project situation, the rechargeable battery may be powered off or trickle-charged. It should be noted that the first preset difference and the second preset difference may be the same value or different values ​​according to project practice.

[0058] In one embodiment, the method for judging the fullness of a rechargeable battery provided by the present application can also obtain the initial battery temperature of the rechargeable battery at the second initial time during the charging process, and after a second preset time interval, obtain the current battery temperature of the rechargeable battery at the second current time during the charging process. The initial battery temperature is subtracted from the current battery temperature to determine the battery temperature difference, and the current battery temperature is updated to the initial battery temperature, and the current battery temperature is continued to be obtained to update the battery temperature difference. Finally, the number of temperature differences that are continuously greater than the preset temperature difference is obtained. When the number of temperature differences is greater than or equal to the preset number of temperature differences, it indicates that the rechargeable battery is saturated. It should be noted that when obtaining the initial battery temperature of the rechargeable battery at the second initial time during the charging process, the specific value of the second initial time needs to be determined. Based on rechargeable batteries calibrated in engineering practice or experiments and the charging process of the rechargeable batteries, a charging temperature curve of the rechargeable battery can be obtained. According to analysis of the charging temperature curve of the rechargeable battery, the slope is significantly larger in the second half of the charging temperature curve. Therefore, the time point when the slope of the entire charging temperature curve begins to exceed the preset temperature slope is set as the second initial time, and the initial battery temperature of the rechargeable battery at the second initial time is obtained.

[0059] In one embodiment, the first initial time and the second initial time can be set to the same value or different values ​​according to different engineering practices. The first preset time interval and the second preset time interval are similar and can be set to the same value or different values.

[0060] It should be noted that the method for judging whether a rechargeable battery is fully charged provided in the present application includes two methods for judging whether a rechargeable battery is fully charged by using the battery voltage difference and the battery temperature difference. The two methods can be used alone or in combination, and both methods can realize the judgment of whether a rechargeable battery is fully charged.

[0061] 4 , another embodiment provides a charging device 200 , including a timing module 210 , a voltage acquisition module 220 , a data processing module 230 , and a temperature acquisition module 240 , which will be described in detail below.

[0062] In one embodiment, the timing module 210 is configured to set a preset first time interval.

[0063] In one embodiment, the voltage acquisition module 220 is connected to the timing module to obtain the initial battery voltage of the rechargeable battery at the first initial time during the charging process, and at the same time, after a first preset time interval set by the timing module 210, obtain the current battery voltage of the rechargeable battery at the first current time during the charging process.

[0064] In one embodiment, when obtaining the initial battery voltage of the rechargeable battery at the first initial time during the charging process, it is necessary to determine the specific value of the first initial time. Based on the rechargeable battery calibrated by engineering practice or experiment and the charging process of charging the rechargeable battery, the charging curve of the rechargeable battery can be obtained. According to the analysis of the charging curve of the rechargeable battery, the slope in the second half of the charging curve will be significantly larger. Therefore, the time point when the slope begins to be greater than the preset value in the entire charging curve is set as the first initial time, and the initial battery voltage of the rechargeable battery at the first initial time is obtained. In one embodiment, the charging process refers to the entire charging process of the rechargeable battery, but there may be current and no current during the charging process. Therefore, as long as there is current or no current during the entire charging process of the battery, it belongs to the charging process. In one embodiment, the rechargeable battery is a nickel-hydrogen battery.

[0065] In one embodiment, the data processing module 230 is connected to the timing module 210 and the voltage acquisition module 220. The data processing module 230 subtracts the initial battery voltage from the current battery voltage to determine the battery voltage difference. At the same time, the data processing module 230 updates the current battery voltage to the initial battery voltage and controls the voltage acquisition module 220 to continue acquiring the current battery voltage. That is, based on the acquired initial battery voltage and the current battery voltage, the initial battery voltage is subtracted from the current battery voltage to determine the battery voltage difference. At the same time, the current battery voltage is updated to the initial battery voltage, and the current battery voltage after the first preset time interval is continuously acquired. The battery voltage difference is recalculated based on the reacquired current battery voltage and the updated initial voltage difference to update the battery voltage difference. The above process is repeated to continuously acquire updated battery voltage differences.

[0066] In one embodiment, the data processing module 230 further obtains the number of times the battery voltage difference is continuously greater than a preset voltage difference. When the number is greater than the preset number, the rechargeable battery is saturated. At this time, the charging device 200 needs to cut off the power to the rechargeable battery or trickle charge the rechargeable battery.

[0067] In one embodiment, when the data processing module 230 determines the number of times the battery voltage difference is greater than the preset voltage difference, it also obtains the last battery voltage difference among the number of times. If the number of times is greater than the preset number and the last battery voltage difference is less than the first preset difference, it can also indicate that the rechargeable battery is fully charged and saturated. At this time, according to the actual project situation, the rechargeable battery may be powered off or trickle-charged.

[0068] In one embodiment, if during the battery charging process, the data processing module 230 determines that the acquired battery voltage difference is continuously greater than the preset voltage difference for less than a preset number of times, the data processing module 230 determines whether the rechargeable battery is saturated based on the battery voltage difference. That is, when the battery voltage difference is less than a second preset difference, the rechargeable battery is saturated. At this time, depending on the actual project situation, the rechargeable battery may be powered off or trickle-charged. It should be noted that the first preset difference and the second preset difference may be the same value or different values ​​depending on project practice.

[0069] In one embodiment, the temperature acquisition module 240 obtains the initial battery temperature of the rechargeable battery at the second initial time during the charging process, and after the second preset time interval set by the timing module, the temperature acquisition module 240 also obtains the current battery temperature of the rechargeable battery at the second current time during the charging process. The data processing module 230 subtracts the initial battery temperature from the current battery temperature to determine the battery temperature difference, and simultaneously updates the current battery temperature to the initial battery temperature, and continues to obtain the current battery temperature to update the battery temperature difference. The data processing module 230 obtains the number of temperature differences that are continuously greater than the preset temperature difference. When the number of temperature differences is greater than or equal to the preset number of temperature differences, it indicates that the rechargeable battery is saturated. It should be noted that when obtaining the initial battery temperature of the rechargeable battery at the second initial time during the charging process, it is necessary to determine the specific value of the second initial time. Based on the experimentally calibrated rechargeable battery and the charging process of the rechargeable battery, a charging temperature curve of the rechargeable battery can be obtained. Analysis of the charging temperature curve of the rechargeable battery shows that the slope is significantly larger in the second half of the charging temperature curve. Therefore, the time point at which the slope of the entire charging temperature curve begins to exceed the preset temperature slope is set as the second initial time, and the initial battery temperature of the rechargeable battery at the second initial time is obtained.

[0070] In one embodiment, the first initial time and the second initial time can be set to the same value or different values ​​according to different engineering practices. The first preset time interval and the second preset time interval are similar and can be set to the same value or different values.

[0071] This application provides a specific embodiment to illustrate the advantages of this technical solution:

[0072] Please refer to Figure 5, which shows the battery temperature, battery voltage, and ambient temperature curves for a certain brand of 2500mAh battery at a current of 1.0A. Analysis of Figure 5 shows that the battery voltage generated a -ΔV after 2.7 hours. The existing -ΔV fullness determination method determines the battery's fullness between 2.9 and 3.0 hours, at which point the battery temperature is already above 45°C, shortening the battery's cycle life. The first initial time in the fullness determination method provided by this application is 1.8 hours. That is, starting at 1.8 hours, the initial battery voltage and current battery voltage are obtained to determine the battery voltage difference, and the number of times the battery voltage difference is continuously greater than a preset voltage difference is obtained. When this number is greater than the preset number, the rechargeable battery is saturated. Using the method provided by this application, the battery fullness determination can be completed between 2.6 and 2.7 hours, at which point the battery temperature is only 37.5°C. In addition to a short charging time, this application also ensures that the battery is fully charged but not overcharged, extending the battery's cycle life.

[0073] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above embodiments can be implemented by hardware or by computer program. When all or part of the functions in the above embodiments are implemented by computer program, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above functions can be implemented. In addition, when all or part of the functions in the above embodiments are implemented by computer program, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and saved in the memory of the local device by downloading or copying, or the system of the local device is updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be implemented.

[0074] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A method for determining fullness of a rechargeable battery, characterized in that: include: Obtaining an initial battery voltage of the rechargeable battery at a first initial time during a charging process; After a first preset time interval, obtaining a current battery voltage of the rechargeable battery at a first current time during the charging process; Subtracting the initial battery voltage from the current battery voltage to determine the battery voltage difference; updating the current battery voltage to the initial battery voltage, and continuing to obtain the current battery voltage to update the battery voltage difference; The number of times that the battery voltage difference is continuously greater than a preset voltage difference is obtained. When the number is greater than or equal to the preset number, the rechargeable battery is saturated.

2. The method for determining fullness of a rechargeable battery as claimed in claim 1, wherein: The acquiring the number of times that the battery voltage difference is continuously greater than the preset voltage difference, and when the number is greater than or equal to the preset number, the rechargeable battery is saturated, includes: The last battery voltage difference value among the times is obtained. When the times are greater than or equal to a preset number of times and the last battery voltage difference value is less than a first preset difference value, the rechargeable battery is saturated.

3. The method for determining fullness of a rechargeable battery as claimed in claim 1, wherein: The step of obtaining an initial battery voltage of the rechargeable battery at a first initial time during the charging process includes: Obtaining a charging curve of the rechargeable battery; The time when the slope of the charging curve is greater than the preset slope is defined as the first initial time.

4. The method for determining fullness of a rechargeable battery as claimed in claim 1, wherein: The method for judging fullness of the rechargeable battery also includes: When the number is less than a preset number, the power of the rechargeable battery is determined according to the battery voltage difference, wherein when the battery voltage difference is less than a second preset difference, the power of the rechargeable battery is saturated.

5. The method for determining fullness of a rechargeable battery as claimed in claim 1, wherein: The method for judging fullness of the rechargeable battery also includes: Obtaining an initial battery temperature of the rechargeable battery at a second initial time during the charging process; After a second preset time interval, obtaining a current battery temperature of the rechargeable battery at a second current time during the charging process; Subtracting the initial battery temperature from the current battery temperature to determine a battery temperature difference; updating the current battery temperature to the initial battery temperature, and continuing to obtain the current battery temperature to update the battery temperature difference; The number of times that the battery temperature difference is continuously greater than the preset temperature difference is obtained. When the number of temperature differences is greater than or equal to the preset number of temperature differences, the rechargeable battery is saturated.

6. A charging device, characterized in that: include: A timing module, used for setting a first preset time interval; a voltage acquisition module, connected to the timing module, for acquiring an initial battery voltage of the rechargeable battery at a first initial time during the charging process, and acquiring a current battery voltage of the rechargeable battery at a first current time during the charging process after a first preset time interval; The data processing module is connected to the timing module and the voltage acquisition module, and is used to subtract the initial battery voltage from the current battery voltage to determine the battery voltage difference; update the current battery voltage to the initial battery voltage, and control the voltage acquisition module to continue to obtain the current battery voltage; the data processing module obtains the number of times the battery voltage difference is continuously greater than the preset voltage difference, and when the number is greater than the preset number, the rechargeable battery is saturated.

7. The charging device according to claim 6, characterized in that: The data processing module acquires the number of times that the battery voltage difference is continuously greater than the preset voltage difference, and when the number is greater than the preset number, the rechargeable battery is saturated, including: The data processing module obtains the last battery voltage difference value among the times. When the times are greater than or equal to a preset number of times and the last battery voltage difference value is less than a first preset difference value, the rechargeable battery is saturated.

8. The charging device according to claim 6, characterized in that: The step of obtaining an initial battery voltage of the rechargeable battery at a first initial time during the charging process includes: The data processing module obtains the charging curve of the rechargeable battery; The time when the slope of the charging curve is greater than the preset slope is defined as the first initial time.

9. The charging device according to claim 6, characterized in that: When the data processing module determines that the number is less than the preset number, the data processing module determines the power of the rechargeable battery according to the battery voltage difference, wherein when the battery voltage difference is less than a second preset difference, the power of the rechargeable battery is saturated.

10. The charging device according to claim 6, characterized in that The charging device also includes a temperature acquisition module; The temperature acquisition module acquires an initial battery temperature of the rechargeable battery at a second initial time during the charging process, and after a second preset time interval set by the timing module, the temperature acquisition module further acquires a current battery temperature of the rechargeable battery at a second current time during the charging process; The data processing module subtracts the initial battery temperature from the current battery temperature to determine the battery temperature difference; updates the current battery temperature to the initial battery temperature, and continues to obtain the current battery temperature to update the battery temperature difference; The number of times that the battery temperature difference is continuously greater than the preset temperature difference is obtained. When the number of temperature differences is greater than or equal to the preset number of temperature differences, the rechargeable battery is saturated.

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