TWI795958B - Calculation method of battery capacity and calculation equipment of battery capacity - Google Patents

Abstract

A calculation method of a battery capacity comprises: determining a size relationship among a battery temperature, a first turning point temperature and a second turning point temperature; setting a first temperature variable capacity and the battery temperature as a dependent variable and an independent variable of a first linear function when the battery e temperature is less than the first turning point temperature and greater than or equal to the second turning point temperature; setting the first temperature variable capacity and the battery temperature as a dependent variable and an independent variable of an exponential function when the battery temperature is less than the second turning point temperature; and calculating an actual battery capacity at least based on an ideal battery capacity and the first temperature variable capacity.

Description

Battery capacity calculation method and battery capacity calculation device

The invention relates to a battery capacity calculation method and a battery capacity calculation device, in particular to a battery capacity calculation method and a battery capacity calculation device considering temperature factors.

As people's demand for battery applications continues to increase, more attention is paid to battery capacity. Since the battery capacity is greatly affected by the temperature factor, a battery capacity compensation mechanism must be designed according to the temperature factor. However, the battery capacity compensation mechanism designed for the temperature factor is not common in the market at present. With the current battery capacity compensation mechanism for temperature factors on the market, the battery internal resistance is first calculated according to the battery temperature, and then the capacity difference is calculated by using the battery internal resistance to perform battery capacity compensation.

The technical problem to be solved by the present invention is to provide a battery capacity calculation method and a battery capacity calculation device for the deficiencies of the prior art.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a battery capacity calculation method, including: detecting the battery temperature of the battery; judging the battery temperature, the first temperature turning point of the battery and the second temperature turning point of the battery The size relationship between; when the battery temperature is less than the first temperature turning point and greater than or equal to the second temperature turning point, the first temperature variable and the battery temperature are set to be the dependent variable and the independent variable of the first linear function respectively; when the battery temperature is less than At the second temperature turning point, the first temperature variable and the battery temperature are respectively set as dependent variables and independent variables of the exponential function; and the actual capacity of the battery is calculated at least based on the ideal capacity of the battery and the first temperature variable.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a battery capacity calculation device, which includes a temperature detector and a processor. The temperature detector detects the battery temperature of the battery, and the processor is electrically connected to the temperature detector. The processor is used to execute the battery capacity calculation method, which includes: judging the size relationship between the battery temperature, the first temperature turning point of the battery, and the second temperature turning point of the battery; when the battery temperature is less than the first temperature turning point and greater than or equal to the second temperature At the turning point, set the first temperature variable and the battery temperature as the strain number and the independent variable of the first linear function respectively; a variable and an independent variable; and calculating the actual capacity based on at least the ideal capacity and the first temperature variable.

In order to solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a battery capacity calculation method, including: detecting the battery temperature of the battery; setting the temperature variable and the battery temperature as the dependent variable and the independent variable of the exponential function respectively; And calculate the actual capacity based on the ideal capacity and temperature variation.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a battery capacity calculation device, which includes a temperature detector and a processor. The temperature detector detects the battery temperature of the battery, and the processor is electrically connected to the temperature detector. The processor is used to execute the battery capacity calculation method, which includes: setting the temperature variable and the battery temperature as dependent variables and independent variables of exponential functions; and calculating the actual capacity according to the ideal capacity and the temperature variable.

One of the beneficial effects of the present invention is that, through the battery capacity calculation device and battery capacity calculation method provided by the present invention, no matter what environment the battery is in, the actual capacity of the battery can be quickly and accurately estimated. In this way, the temperature compensation mechanism is designed according to the calculated actual capacity, so that the remaining capacity displayed by the terminal device loaded with the battery matches the actual usable capacity of the battery.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the provided drawings are only for reference and description, and are not intended to limit the present invention.

The following are specific examples to illustrate the implementation of the "battery capacity calculation method and battery capacity calculation device" disclosed in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various modifications and changes can be made to the details in this specification based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple illustration, and are not drawn according to the actual size, which is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention.

It should be understood that although terms such as "first", "second", and "third" may be used herein to describe various elements or signals, these elements or signals should not be limited by these terms. These terms are mainly used to distinguish one element from another element, or one signal from another signal. In addition, the term "or" used herein may include any one or a combination of more of the associated listed items depending on the actual situation.

In order to quickly and accurately estimate the impact of temperature effects on the actual capacity of the battery, the present invention provides a battery capacity calculation method and a battery capacity calculation device for executing the battery capacity calculation method. Firstly, it is judged whether the battery temperature has reached the temperature turning point of the battery. When the battery temperature reaches the temperature turning point, the battery can completely release the stored capacity (also called electricity). Conversely, when the battery temperature is lower than the temperature turning point, the battery cannot fully release the stored capacity. Through the battery capacity calculation method of the present invention, it is possible to accurately and quickly calculate the percentage of capacity that cannot be released by the battery caused by the temperature effect, so as to design a temperature compensation mechanism for the battery. In the embodiment, the discharge process of the battery is taken as an example, so the ideal capacity of the battery mentioned is the ideal capacity that can be released by the battery, and the actual capacity of the battery is the actual capacity that can be released by the battery affected by the temperature effect.

[first embodiment]

FIG. 1 is a functional block diagram of a battery capacity calculation device according to an embodiment of the present invention. As shown in FIG. 1 , the battery capacity calculation device A includes a temperature detector 1 , a processor 2 and a memory 3 . The temperature detector 1 is electrically connected to the battery B and the processor 2 , and the memory 3 is electrically connected to the processor 2 . The temperature detector 1 is used to continuously detect the battery temperature of the battery B. When the battery B is discharging, the temperature detector 1 continuously detects the battery temperature of the battery B. The battery capacity calculation method is stored in the memory 3 . The battery temperature detected by the temperature detector 1 will be stored in the memory 3 and updated at any time. The processor 2 executes the battery capacity calculation method according to the battery temperature detected by the temperature detector 1 to calculate the actual capacity of the battery B. The details of how the battery capacity calculation method is implemented will be described in FIG. 2 .

Figures 2A-2C are flow charts of the battery capacity calculation method in the first embodiment of the present invention, and the battery capacity calculation method in Figure 2A-Figure 2C can be executed by the battery capacity calculation device A in Figure 1, but not limited thereto . In this embodiment, the battery has two temperature turning points as an example. As shown in FIG. 2A , in step S201 , the temperature detector 1 obtains an initial value of the battery temperature of the battery. Regarding step S203, the processor 2 judges the relationship between the initial value of the battery temperature, the first temperature turning point of the battery, and the second temperature turning point of the battery, wherein the first temperature turning point is greater than the second temperature turning point.

When the processor 2 confirms that the initial value of the battery temperature is greater than or equal to the first temperature turning point of the battery, step S205 is executed. When the processor 2 confirms that the initial value of the battery temperature is less than the first temperature turning point and greater than or equal to the second temperature turning point of the battery, step S207 is executed. When the processor 2 confirms that the initial value of the battery temperature is less than the second temperature turning point, step S209 is executed.

Regarding step S205, the processor 2 calculates the actual capacity of the battery according to the ideal capacity of the battery, the reserved capacity of the battery, and the reserved capacity of the battery. In detail, the reserved capacity of the battery depends on the size of the charging voltage of the battery, and the reserved capacity of the battery depends on the voltage point of the undervoltage protection (UVP), the type of product application or the use demand, and the actual capacity of the battery = the battery Ideal Capacity - Reserved Capacity of the Battery - Reserved Capacity of the Battery.

Regarding step S207 , the processor 2 sets the initial value of the battery temperature and the first temperature variable as the independent variable and dependent variable of the first linear function, respectively, and calculates the first temperature variable. For example, f1(t1)=a1*t1+b1 is a linear function, t1 is the initial value of the battery temperature, f(t1) is the first temperature variable, and a1 and b1 are constants and are related to the cell material of the battery .

Regarding step S209 , the processor 2 sets the initial value of the battery temperature and the first temperature variable as the independent variable and dependent variable of the exponential function, respectively, and calculates the first temperature variable. For example, f2 (t)=a2*(exp(b2*t2+c2))+d2 is an exponential function, t2 is the initial value of the battery temperature, f2(t2) is the first temperature variable, and a2, b2, c2 and d2 are constants and are related to the cell material of the battery.

After step S207 and step S209, step S211 is executed. In step S211, the processor 2 calculates the actual capacity of the battery according to the ideal capacity of the battery, the reserved capacity of the battery, the reserved capacity of the battery and the first temperature variable, wherein the memory 3 stores the formula for calculating the actual capacity of the battery: FCC1= (Qmax-Precap-Rsvdcap)-(Qmax-Precap-Rsvdcap)*(100%-LTempf1), where FCC1 is the actual capacity of the battery, Qmax is the ideal capacity of the battery, Precap is the reserved capacity of the battery, Rsvdcap is the capacity of the battery reserve capacity, and LTempf1 is the first temperature variable.

As shown in FIG. 2B, after step S211, step S213 is executed. In step S213, the temperature detector 1 detects the battery temperature of the battery. After step S213, step S215 is executed. In step S215, the processor 2 judges the magnitude relationship among the battery temperature, the first temperature turning point, and the second temperature turning point. When the processor 2 confirms that the battery temperature is greater than or equal to the first temperature turning point, step S217 is executed. When the processor 2 confirms that the battery temperature is lower than the first temperature turning point and greater than or equal to the second temperature turning point, step S219 is executed. When the processor 2 confirms that the battery temperature is lower than the second temperature turning point, step S221 is executed.

Regarding step S217, the processor 2 obtains a first time point corresponding to the battery temperature reaching the first temperature turning point and a second time point corresponding to the current battery temperature, and calculates a time difference between the second time point and the first time point.

Regarding step S219 , the processor 2 sets the battery temperature and the first temperature variable as the independent variable and dependent variable of the first linear function, respectively, and calculates the first temperature variable. For example, f1(t1)=a1*t1+b1 is a linear function, t1 is the battery temperature, and f(t1) is the first temperature variable.

Regarding step S221 , the processor 2 sets the battery temperature and the first temperature variable as the independent variable and dependent variable of the exponential function, respectively, and calculates the first temperature variable. For example, f2 (t)=a2*(exp(b2*t2+c2))+d2 is an exponential function, t2 is the battery temperature 2, and f2(t2) is the first temperature variable.

After step S217, step S223 is executed. Regarding step S223, the processor 2 sets the time difference and the second temperature variable as the independent variable and dependent variable of the second linear function, respectively. For example, f3(t3)=a3*t3+b3 is the second linear function, t3 is the time difference, f3(t3) is the second temperature variable, and a3 and b3 are constants related to the cell material of the battery.

After step S223, step S225 is executed. In step S225, the processor 2 calculates the actual capacity of the battery according to the ideal capacity of the battery, the reserved capacity of the battery, the reserved capacity of the battery, the first temperature variable, and the second temperature variable. The memory 3 stores the formula for calculating the actual capacity of the battery: FCC2=(Qmax-Precap-Rsvdcap)-(Qmax-Precap-Rsvdcap)*(100%-LTempf1)-(Qmax-Precap-Rsvdcap)*(100%- LTempf2), wherein FCC2 is the actual capacity of the battery, Qmax is the ideal capacity of the battery, Precap is the reserved capacity of the battery, Rsvdcap is the reserved capacity of the battery, LTempf1 is the first temperature variable, and LTempf2 is the second temperature variable. After step S225, return to step S213.

After step S219 and step S221, step S227 is executed. Regarding step S227, the processor 2 calculates the actual capacity of the battery according to the ideal capacity of the battery, the reserved capacity of the battery, the reserved capacity of the battery and the first temperature variable, wherein the actual capacity of the battery is calculated according to the aforementioned calculation formula: FCC1=( Qmax-Precap-Rsvdcap)-(Qmax-Precap-Rsvdcap)*(100%-LTempf1).

After step S227, return to step S213.

As shown in FIG. 2C, after step S205, step S229 follows. In step S229, the temperature detector 1 detects the battery temperature of the battery, followed by step S231. In step S231, the processor 2 judges the magnitude relationship among the battery temperature, the first temperature turning point, and the second temperature turning point. When the processor 2 confirms that the battery temperature is greater than or equal to the first temperature turning point, return to step S205. When the processor 2 confirms that the battery temperature is lower than the first temperature turning point and greater than or equal to the second temperature turning point, step S233 is executed. When the processor 2 confirms that the battery temperature is lower than the second temperature turning point, step S235 is executed.

In step S233 , the processor 2 sets the battery temperature and the first temperature variable as the independent variable and the dependent variable of the first linear function, respectively, and calculates the first temperature variable. In step S235 , the processor 2 sets the battery temperature and the first temperature variable as the independent variable and dependent variable of the exponential function, respectively, and calculates the first temperature variable. After step S233 and step S235, step S237 follows. In step S237, the processor 2 calculates the actual capacity of the battery according to the ideal capacity of the battery, the reserved capacity of the battery, the reserved capacity of the battery and the first temperature variable. After step S237, return to step S229.

For the battery capacity calculation method proposed in FIGS. 2A-2C , for example, when the terminal device loaded with the battery is affected by the ambient temperature, the stored capacity cannot be fully released. Through the battery capacity calculation method proposed in FIGS. 2A-2C , the capacity that the battery cannot normally release due to environmental factors can be quickly estimated. When calculating the capacity that the battery cannot normally discharge, the first discharge stage when the battery temperature is still lower than the temperature turning point and the second discharge stage when the battery temperature has reached the temperature turning point temperature must be taken into consideration at the same time.

In the first discharge stage, if the battery temperature is between the first temperature turning point and the second temperature turning point, the actual capacity of the battery conforms to a linear function. If the battery temperature is lower than the second turning point temperature, the actual capacity of the battery conforms to an exponential function. The actual capacity of the battery in the first discharge stage is the first temperature variable mentioned in FIGS. 2A-2C .

After entering the second discharge stage after the first discharge stage, the battery temperature has reached the first temperature turning point at this time, but the cell material of the battery has not fully recovered at this time, resulting in the battery still not being able to release the stored capacity normally. In the second discharge stage, the actual capacity of the battery conforms to a linear function, and the actual capacity of the battery in the second discharge stage is the second temperature variable mentioned in FIGS. 2A-2C .

FIG. 3 is a graph showing the relationship between the battery temperature and the battery capacity of the first battery. As shown in FIG. 3 , the first battery has only one temperature turning point, which is about 17 degrees Celsius. When the battery temperature of the first battery is greater than or equal to 17 degrees Celsius, the actual capacity of the first battery is about 100%, which means that the first battery can completely release the stored capacity. When the battery temperature of the first battery is less than 17 degrees Celsius, the actual capacity of the battery conforms to an exponential function.

FIG. 4 is a graph showing the relationship between the battery temperature and the battery capacity of the second battery. As shown in Figure 4, the cell material of the second battery in Figure 4 is different from that of the first battery in Figure 3, so the second battery has two temperature turning points, which are about 17 degrees Celsius and minus 8 degrees respectively . When the battery temperature of the second battery is greater than or equal to 17 degrees Celsius, the actual capacity of the second battery is about 100%, which means that the second battery can completely release the stored capacity. When the battery temperature of the second battery is less than 17 degrees Celsius and greater than or equal to minus 8 degrees, the actual capacity of the second battery conforms to a linear function. When the battery temperature of the second battery is less than minus 8 degrees, the actual capacity of the second battery follows an exponential function.

Taking the first battery in FIG. 3 as an example, the accuracy of the battery capacity calculation method in FIGS. 2A-2C is verified below.

As shown in FIG. 3 , the temperature inflection point of the first battery is about 17 degrees Celsius, and the following Table 1 is the experimental data table of the first battery in FIG. 3 . For example, when C-Rate=0.5 and the initial discharge temperature is 12 degrees Celsius, about 6.5% of the capacity cannot be discharged. Discharge rate (C-Rate) Discharge initial temperature (Celsius) Discharge final temperature (Celsius) Discharge time (seconds) Total Discharge Capacity (Amp-Hours) Actual capacity 0.2 11.9 degrees 16.8 degrees 18124 211.09 94.7% 0.5 12 degrees 24.7 degrees 7152 208.41 93.5% 0.2 1.8 degrees 7.6 degrees 15604 181.29 81.3% (Table 1)

Since the discharge initial temperature of the first battery is lower than the temperature turning point of the first battery, the first temperature variable conforms to an exponential function: f2(t2)=-exp(-0.1*t2-2)+1. When t2=12, f2(12) is about 0.96, which means that the first temperature variable (LTempf1) is about 96%.

FIG. 5 is a graph showing the relationship between battery capacity and time after the battery temperature of the first battery in FIG. 3 reaches a temperature turning point. When the battery temperature of the first battery is greater than or equal to the temperature turning point, the actual capacity of the first battery conforms to a linear function. At time T0, although the battery temperature of the first battery has reached the temperature turning point, the first battery can release about 69.3% of its capacity because the cell material of the first battery has not fully recovered. At time T1, the first battery can discharge about 86.7% of its capacity. According to the actual battery capacity corresponding to time T0 and time T1, it can be deduced that the actual capacity of the first battery at this stage conforms to the second linear function: f3(t3)=0.0000412*t3+0.693, where t3 is the current battery temperature The time difference between the time point and time T0, f3(t3) is the actual capacity at this stage, and is also the second temperature variable. At time T2, the battery stops discharging, and the time difference between time T2 and time T0 is substituted into t3, and the second temperature variable is calculated to be about 97.2%.

Finally, substitute the first temperature variable and the second temperature variable into the calculation formula: FCC2=(Qmax-Precap-Rsvdcap)-(Qmax-Precap-Rsvdcap)*(100%-LTempf1)-(Qmax-Precap-Rsvdcap)*( 100%-LTempf2), calculate the percentage of the battery capacity that cannot be released normally due to the temperature effect = (100%-96%)+(100%-97.2%)=6.8%. Compared with the 6.5% shown in Table 1 above, the error between the two is about 0.3%. In this way, it shows that the accuracy of the battery capacity calculation method shown in FIGS. 2A-2C meets actual usage requirements.

Table 2 below is the experimental data table of the third battery. Discharge rate (C-Rate) Battery temperature (Celsius) Total Discharge Capacity (Amp-Hours) Actual capacity 0.2 0 166.73 75.6% 0.5 0.1 174.39 79.0% 0.2 5.6 197.84 89.3% 0.5 4.7 188.96 85.4% 0.2 10 209.92 94.7% 0.5 10 203.95 92.0% 0.2 15 212.57 95.9% 0.5 14.9 212.24 95.7% 0.2 24.8 217.85 98.2% 0.5 25 213.87 96.4% 0.2 40 220.43 99.3% 0.5 40 219.60 99.0% (Table 2)

From the data in Table 2, it can be deduced that the battery temperature and the actual capacity of the third battery conform to an exponential function. Therefore, the present invention proposes the battery capacity calculation method of the second embodiment.

[Second embodiment]

FIG. 6 is a flowchart of a battery capacity calculation method according to a second embodiment of the present invention, and the battery capacity calculation method in FIG. 6 can be executed by the battery capacity calculation device A in FIG. 1 , but not limited thereto. As shown in FIG. 6 , regarding step S601 , the battery temperature of the battery is detected through the temperature detector 1 . Regarding step S603 , through the processor 2 , the temperature variable and the battery temperature are respectively set as dependent variables and independent variables of the exponential function and the temperature variable is calculated. For example, an exponential function: f (t)=a*exp(b*t)+c, t is the battery temperature, f(t) is a temperature variable, and a, b, and c are constants and are related to the cell material of the battery relevant.

Regarding step S605, the processor 2 calculates the actual capacity of the battery according to the ideal capacity, the reserved capacity of the battery, the reserved capacity of the battery and temperature variables, and the formula for calculating the actual capacity FCC2 of the battery is stored in the memory 3: FCC2= Qmax*Tempf-Precap-RsvdCap. FCC2 is the actual capacity of the battery, Qmax is the ideal capacity of the battery, LTempf is the temperature variable, Precap is the reserved capacity of the battery, and Rsvdcap is the reserved capacity of the battery. Since the ideal capacity, the reserved capacity of the battery, and the reserved capacity of the battery are all preset values, the calculated temperature variable is substituted into the above calculation formula to calculate the actual capacity of the battery.

[Advantageous Effects of Embodiment]

One of the beneficial effects of the present invention is that, through the battery capacity calculation device and battery capacity calculation method provided by the present invention, the actual capacity of the battery can be quickly and accurately estimated regardless of the environment the battery is in. In this way, a temperature compensation mechanism can be designed for the battery according to the calculated actual capacity, so that the remaining capacity displayed by the terminal device loaded with the battery matches the actual usable capacity.

The content disclosed above is only a preferred feasible embodiment of the present invention, and does not therefore limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. within the scope of the patent.

A: Battery capacity calculation device 1: Temperature detector 2: Processor 3: Memory B: battery Step S201~Step S237 Step S601~Step S605

FIG. 1 is a functional block diagram of a battery capacity calculating device according to a first embodiment of the present invention.

2A-2C are flowcharts of the battery capacity calculation method according to the first embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the battery temperature and the battery capacity of the first battery.

FIG. 4 is a graph showing the relationship between the battery temperature and the battery capacity of the second battery.

FIG. 5 is a graph showing the relationship between the battery capacity and the battery discharge time after the battery temperature of the first battery in FIG. 3 reaches a first temperature turning point.

FIG. 6 is a flowchart of a battery capacity calculation method according to a second embodiment of the present invention.

Step S601~Step S605

Claims (8)

A battery capacity calculation method, comprising: detecting a battery temperature of a battery; judging the relationship between the battery temperature, a first temperature turning point of the battery, and a second temperature turning point of the battery; when the battery temperature is less than When the first temperature turning point is greater than or equal to the second temperature turning point, set a first temperature variable and the battery temperature as a variable and an independent variable of a first linear function; when the battery temperature is lower than the first 2. At the turning point of temperature, set the first temperature variable and the battery temperature as a dependent variable and an independent variable of an exponential function respectively; and calculate an actual capacity of the battery based on at least an ideal capacity of the battery and the first temperature variable capacity. The battery capacity calculation method as described in Claim 1 further includes: after setting the first temperature variable, judging whether the battery temperature is greater than or equal to the first temperature turning point, when it is confirmed that the battery temperature is greater than or equal to the first temperature When turning point, set a second temperature variable and a time difference as a dependent variable and an independent variable of a second linear function; and calculate the actual capacity according to the ideal capacity, the first temperature variable and the second temperature variable. The battery capacity calculation method as described in claim 2, wherein the actual capacity is calculated according to a formula: FCC=(Qmax-Precap-Rsvdcap)-(Qmax-Precap-Rsvdcap)*(100%-LTempf1)-(Qmax-Precap -Rsvscap)*(100%-LTempf2), wherein FCC is the actual capacity, Qmax is the ideal capacity, Precap is a reserved capacity of the battery, Rsvdcap is a reserved capacity of the battery, LTempf1 is the first temperature variable , and LTempf2 is the second temperature variable. The battery capacity calculation method as described in Claim 1, wherein the first linear function is f(t)=a*t+b, wherein f(t) is the first temperature variable, t is the battery temperature, and a and b are constants. The battery capacity calculation method as described in Claim 1, wherein the exponential function is f(t)=a*exp(b*t+c)+d, wherein f(t) is the first temperature variable, and t is the battery temperature, and a, b, c and d are constants. The battery capacity calculation method as described in Claim 2, wherein the second linear function is f(t)=a*t+b, wherein f(t) is the second temperature variable, t is the time difference, and a and b is a constant. The battery capacity calculation method according to claim 2, wherein the time difference is a difference between a first time point corresponding to the battery temperature and a second time point corresponding to the battery temperature reaching the first temperature turning point. A battery capacity calculation device, comprising: a temperature detector for detecting a battery temperature of a battery; and a processor electrically connected to the temperature detector to obtain the battery temperature; wherein the processor is used for Execute a battery capacity calculation method, and the battery capacity calculation method includes: judging the size relationship between the battery temperature, a first temperature turning point of the battery, and a second temperature turning point of the battery; when the battery temperature is lower than the first temperature turning point When a temperature turning point is greater than or equal to the second temperature turning point, set a first temperature variable and the battery temperature as a variable and an independent variable of a first linear function; when the battery temperature is lower than the second temperature At the turning point, set the first temperature variable and the battery temperature as a dependent variable and an independent variable of an exponential function, respectively; and An actual capacity of the battery is calculated at least according to an ideal capacity of the battery and the first temperature variable.

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