KR100322687B1 - Method for estimating capacity of battery loaded in mobile phone - Google Patents

Abstract

The present invention uses a battery to charge and discharge a small amount of current to measure an accurate capacity of the battery and use the measured capacity value as initial value data for indicating the remaining capacity of the battery mounted on the mobile communication terminal. The present invention provides a battery capacity measuring method for displaying an accurate battery remaining amount, comprising: charging a first battery by applying a current for a predetermined period of time; A first step of connecting a voltage measuring device; The first battery capacity is calculated using the voltages measured for each measurement time period after measuring the voltage of the first battery at regular time intervals while flowing the current of the first battery to the load, A second step of creating a table divided into time zones; A third step of charging a second battery of the same type as that of the first battery by applying a current equal to a current applied when the first battery is charged; A fourth step of connecting the load and the voltage measuring device to the second battery and measuring the voltage of the second battery at regular time intervals while flowing the current of the second battery to the load; And a fifth step of determining the capacity of the second battery by finding a battery capacity corresponding to an average voltage value of the voltage value of the second battery measured for each time period in the above table.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for measuring a capacity of a battery mounted on a mobile communication terminal,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a residual capacity of a battery mounted on a mobile communication terminal, and more particularly to a method for accurately measuring a capacity of a battery by charging the battery with a small amount of current for a predetermined period of time, will be.

2. Description of the Related Art Generally, a mobile communication terminal uses a rechargeable battery that stores energy because an individual uses it for portable use. Such a battery is charged in a mobile communication terminal after being used for a certain period of time and then discharged. Accordingly, in order to inform the user of the replacement timing of the battery, the mobile communication terminal displays the remaining amount of the mounted battery through the liquid crystal screen.

Therefore, the mobile communication terminal has a program for calculating the remaining amount of the mounted battery, and calculates the remaining amount of the battery based on the amount of residual current applied from the battery mounted by the program. Then, the mobile communication terminal determines the state of charge and discharge of the battery through the calculated remaining amount of the battery, and displays it on the liquid crystal screen. Here, the mobile communication terminal compares the calculated remaining capacity of the battery with the capacity of the battery to determine the state of charge and discharge of the battery. That is, the mobile communication terminal can accurately determine the state of charge and discharge of the battery only by knowing the capacity of the battery accurately.

In order to check the capacity of the battery, conventionally, the capacity of the battery is measured by checking the time taken until the fully charged battery is completely discharged.

However, in such a conventional battery capacity measuring method, it is almost impossible to measure the battery capacity in a fully charged state and a discharged state of the battery. By measuring the battery capacity in a state substantially close to full charge and full discharge, The communication terminal can not accurately know the capacity of the mounted battery, so that the mobile communication terminal does not display the charging and discharging state of the battery to the user more accurately.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide an apparatus and a method for measuring a battery capacity of a mobile terminal by charging and discharging the battery with a small amount of current, The present invention also provides a battery capacity measuring method for displaying a battery remaining amount to a user of a mobile communication terminal.

1 is a configuration diagram of a battery to which the present invention is applied;

FIG. 2 is a characteristic diagram of changes in current and voltage according to time during battery discharge according to the present invention. FIG.

3 is a flowchart illustrating a method of measuring a capacity of a battery mounted on a mobile communication terminal according to an embodiment of the present invention.

Description of the Related Art [0002]

11: cell 12: protection circuit

13: Amperemeter

According to an aspect of the present invention, there is provided a method of arbitrarily measuring a capacity of a battery mounted on a mobile communication terminal, the method comprising: charging a first battery by applying a current for a predetermined time, And a first voltage measuring device for measuring a voltage at the time of discharging; Calculating the first battery capacities using voltages measured for each measurement time period after measuring a voltage of the first battery at regular time intervals while flowing a current of the first battery to the first load, A second step of preparing a table in which the first battery capacity is classified according to each measurement time period; A third step of charging a second battery of the same type as that of the first battery by applying a current equal to a current applied when the first battery is charged; A fourth step of connecting a second load and a second voltage measuring device to the second battery and measuring a voltage of the second battery at regular time intervals while flowing a current of the second battery to the second load; And determining a capacity of the second battery by finding a battery capacity corresponding to an average value of the voltage values of the second battery measured for each time period in the table.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of a battery to which the present invention is applied. The battery 11 includes a cell 11 for charging and discharging power, a protection circuit 12 for protecting the cell 11, And a current amount counter (13) for counting the amount of current flowing out of the cell (11).

Here, the protection circuit 12 is connected between the cell 11 and the current amount counter 13, and the current amount counter 13 is connected between the protection circuit 12 and the power input / output terminals + and -.

The counter 13 counts the amount of current flowing into or out of the cell 11 through the power input / output terminals (+, -) and delivers the counted current amount to the mobile communication terminal. At this time, the amount of current counted by the counter 13 is not transmitted to the mobile communication terminal through the power input / output terminals (+, -), but is transmitted to the mobile communication terminal through another communication terminal.

Of course, the mobile communication terminal on which the battery is mounted is provided with power terminals (+, -) connected to the power input / output terminals (+, -) of the battery for receiving power, And a battery connection communication terminal for receiving the counted current amount.

Therefore, when the battery is mounted on the mobile communication terminal, the power terminals (+, -) of the battery are correspondingly connected to the power terminals (+, -) of the mobile communication terminal by corresponding polarity terminals, The communication terminal is connected to the battery connection communication terminal of the mobile communication terminal.

When the battery is completely connected to the mobile communication terminal, when the mobile communication terminal is used, the charging current of the cell 11 is discharged and applied to the mobile communication terminal. At this time, the current amount counter 13 counts the amount of current discharged from the cell 11 and transmits the counted amount to the mobile communication terminal. Then, the mobile communication terminal judges the discharge state of the cell 11 through the counted amount of the discharge current, 11 on the liquid crystal screen.

When the cell 11 is charged through the charger while the battery and the mobile communication terminal are connected as described above, the current amount counter 13 counts the amount of charge current applied from the charger to the cell 11 To the mobile communication terminal. Then, the mobile communication terminal determines the state of charge of the cell 11 through the amount of charge current counted by the current amount counter 13, and displays the state of charge on the liquid crystal screen.

The protection circuit 12 prevents the cell 11 from being overcharged by the overcurrent and the overvoltage, and also prevents the cell 11 from being overdischarged.

Hereinafter, the concept for facilitating understanding according to the embodiment of the present invention will be described in more detail as follows.

If accurate data on the cell capacity of the battery is required, it is necessary to directly charge and discharge the battery to find the total capacity, and there is no way to know how much capacity is at any point. For example, when a cell of a battery made by a third party is purchased and its capacity is checked, the method of determining the residual capacity of the cell is impossible without performing a complete discharge.

In order to solve such a problem, the battery is first charged with a small amount of current. However, in this case, it is preferable to charge with a current of 0.4 [A] or less.

When charging is finished, the voltage and current data are acquired while discharging at the same current. That is, when the discharge starts, the amount of change in the voltage and the amount of the discharge current are obtained as data on time. At this time, the amount of current is constant, but the voltage changes with time. The characteristic of the change of the current and the voltage with the passage of time during the battery discharge is as shown in FIG.

The relationship between the capacity of the battery and the voltage is dataized while the user continues to discharge until the desired voltage is reached. At this time, if the total capacity of the battery is denoted by C, the measured time is denoted by T, and the current is denoted by A, the capacity of the battery is obtained as shown in the following Equation (1).

C = A x T = AT [mAH]

Here, if the sampling interval for measuring the voltage is t _s and N samples are used, it can be expressed by the following equations (2) and (3).

T = t _s x N

C = A xt _s x N

The results of Equations (1) and (2) are the same, but the case of Equation (3) can be calculated by substituting the actual measurement result and the data can be digitized according to a constant sample interval.

The C value calculated as in Equations (1) to (3) above is simply the total capacity of the battery, but the value of its complement is required. That is, a formula is required in which the capacity of the battery is C in the fully charged state, and the capacity is set to '0' at the time t.

Therefore, at any time point t _n to be calculated as shown in the following equation (4), the current residual capacity c _n is calculated as shown in the following equation (5). However, n (an integer equal to or greater than '0') is time.

t _n = t _s xn

c _n = C - A xt _n

Using the above equation (5), the residual capacity value according to the time of discharging by the A current can be obtained. At this time, if the voltage change is V _n , the data shown in [Table 1] can be generated. The data in the following [Table 1] is an example in which the voltage until the voltage of the battery reaches 3.2 V is set to 100%.

Time (n) Residual capacity (c _n ) The voltage (V _n ) 0 100 4.2 One 99.8 4.19 2 99.7 4.19 ... ... ... 130 1.0 3.21 131 0.3 3.21 132 0.0 3.2

By taking a plurality of such data and taking an average value, the average capacity-to-voltage data can be obtained.

The residual capacity of an arbitrary battery (however, the battery of the same type) at any time based on the data thus created becomes a capacitance value corresponding to the measured voltage value (V _n ) when the current A (mA) flows .

That is, if the measured voltage is V _n , the capacitance becomes c _n .

The procedure for measuring the relationship between the total capacity of the battery and the voltage and capacity is as follows.

First, the battery is charged with the current A [mA] and the voltage V [mV].

Second, in the case of lithium ion, charging current is reduced, and when it flows below a certain current, charging is stopped.

Third, connect a device capable of measuring voltage and start discharging with current A [mAM].

Fourth, the voltage value [V _n ] is read at a constant time interval t _n and the capacity is calculated as shown in [Table 2] and the data is tabulated.

time Battery capacity Voltage n-1 c _n-1 V _{n + 1} n c _n V _n N + 1 c _{n + 1} V _{n + 1}

In Table 2, C _n-1 , C _n and C _{n + 1} are battery capacity values calculated as shown in the following equations (6), (7) and (8), respectively.

C _n-1 = C - A xt _s x (n-1)

Here, the calculated C _n-1 is the battery capacity when V _n-1 , which is the voltage measured at time 'n-1'.

C _n = C - A xt _s xn

Here, the calculated C _n is the battery capacity when V _n , which is the voltage measured at time n.

C _{n + 1} = C - A x t _s x (n + 1)

Here, the calculated C _{n + 1} is the battery capacity when V _{n + 1} , which is the voltage measured at time 'n + 1'.

On the other hand, in Table 2, the actual capacity of the battery is C _{n, which} is the battery capacity when the voltage is V _n .

When the data as shown in [Table 2] is completed, the capacity for an arbitrary battery is measured according to the procedure shown in FIG. However, it is necessary to connect the equipment that can discharge the battery with the constant current A [mA] and the equipment that can measure the voltage precisely. The load is connected in series to the battery, and the voltage measuring equipment is connected in parallel.

FIG. 3 is a flowchart illustrating a method of measuring a capacity of a battery mounted on a mobile communication terminal according to an embodiment of the present invention. Referring to FIG. 3, a process of measuring a capacity of a battery at an arbitrary point in time will be described in detail as follows.

First, a small amount of current of 0.4 [A] or less is applied to charge the first battery for a predetermined period of time (301), and it is determined (302) whether the charging current is smaller than the current at the time of first charging. And then the first battery is charged.

If it is determined in step 302 that the charging current has decreased to a predetermined value or less, the charging of the first battery is stopped and a voltage measuring device for measuring the load and discharging voltage for discharging current in the first battery (303).

In this way, while the load and the voltage measuring device are connected, the voltage V _n of the first battery is measured (304) at a constant time interval t _s while flowing the current of the first battery to the load. However, the magnitude of the current discharged to the load is equal to the magnitude of the current applied to the first battery during charging.

When the voltages V _n-1 , V _n , and V _{n + 1} are measured for each time (n-1, n, n + 1) After calculating the battery capacities C _n-1 , C _n and C _{n + 1} , a table as shown in Table 2 is prepared (305). The table thus prepared is used as measurement data of battery capacity of the same type as that of the first battery.

Next, a process of measuring the second battery capacity of the same type as that of the first battery using the table of the battery capacity for the first battery will be described.

(306) after charging the second battery by applying the same current as a small amount of current applied during charging of the first battery, after connecting a load to the second battery, (307). However, the magnitude of the current discharged to the load is the same as the magnitude of the current applied to the second battery during charging.

In this manner, the voltage measuring device is connected to the second battery while the current of the battery flows to the load, and the voltage V _n of the second battery is measured at a predetermined time interval t _s (308).

Next, the table created in the table creating process 305 is analyzed to find the battery capacity corresponding to the voltage V _n for the second battery, and determines the capacity at this time as the capacity of the second battery 309 ).

It is to be noted that the technical idea of the present invention has been specifically described in accordance with the above preferred embodiment, but the above-mentioned embodiments are intended to be illustrative and not restrictive. In addition, it will be understood by those of ordinary skill in the art that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the present invention accurately measures the capacity of batteries of the same type and uses the measured capacity value as initial value data for displaying the battery remaining amount mounted on the mobile communication terminal, thereby displaying a more accurate battery remaining amount to the user So that the reliability and competitiveness of the product can be remarkably enhanced.

Claims (6)

A method for arbitrarily measuring a capacity of a battery mounted on a mobile communication terminal, A first step of charging the first battery with a current for a predetermined time and then connecting a first load for current discharge to the first battery and a second voltage measuring device for measuring a voltage during discharging; Calculating the first battery capacities using voltages measured for each measurement time period after measuring a voltage of the first battery at regular time intervals while flowing a current of the first battery to the first load, A second step of preparing a table in which the first battery capacity is classified according to each measurement time period; A third step of applying current to a second battery of the same type as that of the first battery to charge the second battery; A fourth step of connecting a second load and a second voltage measuring device to the second battery and measuring a voltage of the second battery at regular time intervals while flowing a current of the second battery to the second load; And A fifth step of determining a capacity of the second battery by finding a battery capacity corresponding to an average voltage value of the voltage values of the second battery measured for each time zone, And measuring the battery capacity. The method according to claim 1, In the first step, A first step of charging the first battery for a predetermined time by applying a small amount of current substantially equal to or less than 0.4 [A]; A first step of determining whether a charging current of the first battery is less than a current of the first battery; If the current is not decreased as a result of the determination, And If the current is decreased as a result of the determination, connecting the load and the voltage measuring device to the first battery, And measuring the battery capacity. The method according to claim 1, The second step comprises: A second step of measuring the voltage of the first battery using the second voltage measuring device at regular time intervals while flowing the current of the first battery to the second load; And Calculating the first battery capacities using the voltages measured for each measurement time period, and creating the table in which the calculated first battery capacities are classified according to each measurement time period; And measuring the battery capacity. The method of claim 3, Wherein the magnitude of the current discharged to the first load is equal to the magnitude of the current applied to the first battery during charging. The method according to claim 1, Wherein the magnitude of the current discharged to the second load in the fifth step is equal to the magnitude of the current applied to the second battery during charging. 6. The method according to any one of claims 1 to 5, Wherein when the second battery is charged, a current equal to the current applied to the first battery is applied.