KR20070060215A - Method and apparatus of correcting full charge capacity and end of discharge voltage - Google Patents

Abstract

A method and apparatus for correcting charge capacity of a battery and a discharge restricting voltage is provided to stably operate a portable electronic appliance by correcting the charge capacity of the battery by considering deterioration due to different temperature or the number of the charge or discharge in the respective battery cells. A current sensing unit(112) senses a current of a battery. A voltage sensing unit(108) senses a voltage of the battery. A memory unit(104) stores the capacity from a full charge state of the battery to the low charge capacity. In a control unit(102), a residual capacity from a low charge state of a battery to shutdown is measured. A first value obtained by adding the residual capacity to the capacity from a full charge state of the battery to the low charge capacity is corrected as the charge capacity of the battery. The residual capacity is calculated by counting times from the low charge state to the shutdown and multiplying the count time by voltage and current of the battery.

Description

Battery charging capacity and discharge limit voltage correction method and device {METHOD AND APPARATUS OF CORRECTING FULL CHARGE CAPACITY AND END OF DISCHARGE VOLTAGE}

1 is a block diagram of a battery management apparatus according to a preferred embodiment of the present invention.

2 and 3 are a flow chart of a battery charge capacity and discharge limit voltage correction method according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: battery management unit

102: control unit

104: memory section

106: clock generator

108: voltage sensing unit

110: communication unit

112: current sensing unit

114: sensing resistance

The present invention relates to a battery management method and apparatus, and more particularly, to a method and apparatus for correcting the charge capacity and discharge limit voltage of a battery.

Generally, when the remaining capacity of the battery falls below a predetermined value, the portable electronic device enters a power saving mode to protect data in operation through the portable electronic device or to prevent abnormal operation by the battery having a low remaining capacity. Allow the device to operate reliably.

However, the charge capacity of the battery is often incorrectly measured by the number of charges of the battery, a sudden change in temperature, and the like.

In more detail, a battery pack (secondary battery) including a lithium ion battery has its charge capacity determined for each battery pack, but the charge capacity varies depending on the temperature used.

For example, during low temperature use, the internal impedance of the battery cell becomes high, so that the voltage drop increases when the same current value is passed, and the charge capacity of the battery pack decreases.

In addition, the battery pack is characterized in that the charging capacity is reduced even when the number of charge and discharge increases. This is because the battery cell is deteriorated by repeated charge and discharge, and the usable capacity is reduced, which is called cycle deterioration.

As such, the charge capacity of the battery is changed by cycle deterioration due to repeated charge / discharge cycles, and an error occurs between the calculated battery residual capacity and the actual battery residual capacity.

In order to solve this problem, various methods have been proposed.

For example, Korean Patent Office No. 10-2004-0092389 filed under the name of the method for calculating the battery pack and the remaining battery charge, the temperature measuring means for measuring the temperature of the battery cell, and the number of charge and discharge counting the number of charge and discharge Counting means, correction value storage means for changing a predetermined number of charge and discharge cycles, and storing correction values for calculating a battery remaining amount according to the temperature, and storing the correction value based on the measured temperature and the counted charge and discharge counts. Disclosed is a battery pack having a remaining amount calculating means for searching for means to determine the corrected value and calculating a remaining battery amount according to the corrected value. This prior art makes it possible to correct the error of the residual capacity generated according to the number of charge and discharge and temperature.

In addition, Patent No. 10-2001-0029768, filed with the Korean Intellectual Property Office for the method of correcting the remaining capacity of a smart battery, refers to variables such as current, charge / discharge frequency, and temperature when measuring the remaining capacity of a smart battery used in a portable electronic device. Disclosed is a method of correcting a residual capacity of a smart battery, which calculates a voltage of a specific capacity and corrects the residual capacity with the calculated voltage of the specific capacity so that the accuracy of the residual capacity can be improved. This prior art makes it possible to correct the error of the residual capacity generated according to the current, the number of charge and discharge, the temperature variable.

As described above, various methods for correcting the error of the remaining capacity of the battery have been proposed. However, since the characteristics such as the degree of deterioration according to the temperature and the number of charge / discharge cycles are different for each battery cell, the above-described conventional method alone cannot accurately correct the remaining capacity of the battery.

Accordingly, there is an urgent need for the development of a technology capable of accurately detecting the remaining capacity of a battery in consideration of characteristics such as deterioration according to different temperatures and the number of charge and discharge cycles.

The present invention is to overcome the above-mentioned conventional problems, and to provide a battery charge capacity correction method and apparatus for correcting the charge capacity of the battery in consideration of characteristics such as deterioration degree according to different temperatures and the number of charge and discharge for each battery cell For the purpose of

In addition, another object of the present invention is a battery discharge limit voltage correction method for correcting the discharge limit voltage of the battery to correspond to the battery's charge capacity detected in consideration of characteristics such as temperature and the number of deterioration according to the number of charge and discharge of each battery cell and To provide a device.

The battery charge capacity correction method according to the present invention for achieving the above object and to solve the problems of the prior art is to measure the remaining capacity from the low charge state of the battery to the shutdown, and the full charge state of the battery And correcting the first value obtained by adding the remaining capacity to the capacity until reaching a low charge state with the charge capacity of the battery.

The battery discharge limit voltage correction method according to the present invention includes the steps of measuring a remaining capacity from a low charge state of a battery to a shutdown, and a discharge limit voltage of the battery with a discharge limit voltage previously stored corresponding to the remaining capacity. It characterized in that it comprises a step of correcting.

The present invention corrects the charge capacity (FCC) of the battery based on the actual remaining capacity (shut-SOC) from the low charge state to the shutdown state to determine the entry into the power saving mode, according to the temperature and the number of charge and discharge cycles It is possible to accurately calculate the charging capacity even if the characteristics such as deterioration degree are different.

In addition, by correcting the discharge limit voltage (C-EDV) according to the charge capacity (FCC), it is possible to protect the battery and to operate the device that is powered from the battery normally.

The configuration of the battery management apparatus according to the preferred embodiment of the present invention will be described with reference to FIG. 1.

The battery management apparatus 100 is a MCU usually referred to by the name of a fuel gauging IC. The controller 102 of the battery management apparatus 100 controls the battery management apparatus 100 as a whole, and in particular, charges the battery V based on the actual remaining capacity (shut-SOC) according to the preferred embodiment of the present invention. Correct the capacitance (FCC) and discharge limit voltage (C-EDV).

The memory unit 104 stores a variety of information including a processing program of the control unit 102, and particularly includes a discharge limit voltage correction table according to a preferred embodiment of the present invention. The discharge limit voltage correction table stores a discharge limit voltage C-EDV corresponding to each of a plurality of actual remaining shut-SOCs, and is actually stored at predetermined level intervals in consideration of the load of the memory unit 104. It stores the discharge limit voltage (C-EDV) for each residual capacity (shut-SOC), and obtains the discharge limit voltage (C-EDV) by interpolating the actual residual capacity (shut-SOC) between the level intervals. do.

In addition, the memory unit 104 may have a discharge limit voltage (C-EDV), a residual capacity (FCC) of a battery V, a shutdown voltage, and a discharge capacity from a fully charged state to a low charge state according to a preferred embodiment of the present invention. (DCR), a value before updating the charging capacity (FCC) (FCC_BEFORE), and the like, and a correction flag is provided. Here, the correction flag is a flag indicating whether discharge has continued in the power saving mode and shutdown has been reached.

The clock generator 106 generates a clock for the operation of the battery management apparatus 100 and provides the clock to each unit.

The voltage sensing unit 108 senses the voltages V +, V−, VH, and VL of the battery V, and provides the result to the controller 100.

The communication unit 110 is responsible for communication between the portable electronic device provided with the battery V and the control unit 102, and is provided with a clock and data terminal for communication with the portable electronic device.

The current sensing unit 112 senses the current of the battery V through the sensing resistor 114, and provides the result to the controller 100.

The sensing resistor 114 is connected in series to the power output path of the battery V.

Now, a battery charging capacity and a discharge limit voltage correction method according to a preferred embodiment of the present invention applicable to the battery management apparatus will be described in detail with reference to FIGS. 2 and 3.

The controller 102 checks whether the portable electronic device with the battery V enters the power saving mode (step 200).

When the voltage of the battery V corresponds to the discharge limit voltage C-EDV stored in the memory 104, the controller 102 transmits a power saving mode entry command to the portable electronic device. The portable electronic device having received the power saving mode entry command enters the power saving mode according to the power saving mode entry command, thereby protecting the portable electronic device and the battery V.

When the battery V enters the power saving mode as the voltage of the battery V corresponds to the discharge limit voltage C-EDV, the controller 102 counts the shutdown time (step 202). In this case, the shutdown time is for calculating the actual remaining shut-SOC of the battery V, and the shutdown refers to power off.

In more detail, the present invention counts the shutdown time from entering the power saving mode, that is, from the low charge state until the battery V is shut down, and the shutdown time and the current sensing value and voltage provided by the current sensing unit 122. The actual residual capacity (shut-SOC) of the battery V is calculated by multiplying the voltage sensing value provided by the sensing unit 108.

When the counting of the shutdown time starts, the controller 102 checks whether the voltage of the battery V is a predetermined shutdown voltage. If the voltage of the battery V is a shutdown voltage, the controller 102 checks whether it is in a power saving mode. That is, the controller 102 checks whether charging is not started and the power saving mode is maintained until the shutdown voltage is reached (steps 206 and 208).

If the power saving mode is maintained until the shutdown voltage is reached, the control unit 102 sets the correction flag to 1, stores the counted shutdown time, and then executes shutdown (step 210).

Unlike the above, when charging is performed in the power saving mode, the controller 102 resets the correction flag to 0 (step 212).

As described above, the control unit 102 counts the shutdown time for calculating the actual remaining shut-SOC whenever the voltage of the battery V reaches the discharge limit voltage C-EDV and enters the power saving mode. The correction flag is reset or set depending on whether charging is performed in the power saving mode or shutdown is performed.

A method of correcting the battery charge capacity and the discharge limit voltage using the shutdown time and the correction flag will now be described with reference to FIG. 3.

The controller 102 checks whether charging starts as the external power is input (step 300). When the charging is started, the control unit 102 calculates the actual remaining capacity (shut-SOC) from the low charge state to the shutdown state (step 302). The actual remaining capacity (shut-SOC) is calculated by multiplying the shutdown time by the current sensing value provided by the current sensing unit 122 and the voltage sensing value provided by the voltage sensing unit 108.

When the actual remaining capacity (shut-SOC) is calculated, the controller 102 checks whether the correction flag is set (step 304). In other words, it checks whether the shutdown has been performed in the power saving mode. If the correction flag is reset, the control unit 102 calculates the first and second charge amounts FCC1 and 2 according to the following equations (1) and (2).

Equation 1 is for calculating the first charge amount FCC1 without considering the actual residual capacity (Shut-SOC) according to the characteristics of the battery V, wherein the DCR is charged from a fully charged state to a low charge state. BATTERY LOW% represents the charge capacity discharged from the low charge state to the shutdown state to the charge capacity (FCC), and FCC_BEFORE represents the value before updating the charge capacity (FCC).

The above Equation 1 is a formula for calculating a general charging capacity without considering the actual remaining capacity (shut-SOC) according to the characteristics of the battery V, and the discharged capacity from the fully charged state to the low charged state ( The first charge amount FCC1 is calculated by adding the charge capacity BATTERY LOW% * FCC_BEFORE discharged from the low charge state to the shutdown state to DCR).

Equation (2) calculates the second charge capacity (FCC2) by adding the actual capacity (Shut-SOC) discharged from the low charge state to the shutdown state to the discharged capacity (DCR) from the full charge state to the low charge state. This is the value to which the actual residual capacity (shut-SOC) is applied according to the characteristics of the battery (V).

When the first and second charge amounts FCC1 and 2 are calculated, the control unit 102 checks whether the second charge amount FCC2 is greater than the first charge amount FCC1. If the second charge amount FCC2 is not greater than the first charge amount FCC1, it is determined that the charge capacity of the battery V does not need to be corrected according to the actual remaining capacity SOFT. The battery charge capacity (FCC) is corrected according to the charge capacity (FCC1).

After the correction of the charging capacity FCC, the control unit 102 extracts a discharge limit voltage corresponding to the actual remaining capacity (shut-SOC) with reference to the discharge limit voltage correction table, and applies the extracted discharge limit voltage to the extracted discharge limit voltage. Correct the discharge limit voltage accordingly.

Unlike the above, when the second charge amount FCC2 is greater than the first charge amount FCC1, it is determined that the charge capacity of the battery V needs to be corrected according to the actual remaining capacity SOFT. The charging capacity FCC of the battery is corrected according to the second charging capacity FCC2.

After the correction of the charging capacity FCC, the control unit 102 extracts a discharge limit voltage corresponding to the actual remaining capacity (shut-SOC) with reference to the discharge limit voltage correction table, and applies the extracted discharge limit voltage to the extracted discharge limit voltage. Correct the discharge limit voltage accordingly.

On the other hand, if the correction flag is set in step 304, the control unit 102 calculates the second charge amount (FCC2) according to equation (2) (step 312). When the second charge amount FCC 2 is calculated, the controller 102 corrects the charge capacity FCC of the battery according to the second charge amount FCC 2.

After the correction of the charging capacity FCC, the control unit 102 extracts the discharge limit voltage corresponding to the actual remaining capacity (shut-SOC) with reference to the discharge limit voltage correction table, and extracts the extracted discharge limit voltage. Correct the discharge limit voltage accordingly.

In the above-described preferred embodiment of the present invention, only the determination of the discharge limit voltage corresponding to the actual remaining capacity from the low charge state to the shutdown state using the discharge limit voltage correction table is illustrated. The discharge limit voltage corresponding to the actual residual capacity may be calculated using a function according to the correspondence relationship between voltages.

Embodiments of the present invention described above include a computer readable medium including program instructions for performing various computer-implemented operations. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Such computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and floppy disks. Magneto-optical media, and ROM, RAM, flash memory, and the like may be employed, and may include hardware devices specifically configured to store and execute program instructions. The medium may also be a transmission medium such as an optical or metal wire, a waveguide, or the like including a carrier wave for transmitting a signal specifying a program command, a data structure, or the like. The program instructions include not only machine code generated by a compiler, but also high-level language code executable by a computer using an interpreter or the like.

As described above, the present invention corrects the charging capacity of a battery in consideration of characteristics such as temperature and the number of deterioration according to the number of charge and discharge cycles, thereby stably operating the battery and the portable electronic device including the battery. There is an advantage to this.

In addition, the present invention is a portable type having the battery and the battery by correcting the discharge limit voltage of the battery to correspond to the charge capacity of the detected battery in consideration of characteristics such as temperature and the number of deterioration according to the number of times of charge and discharge for each battery cell There is an advantage that the electronic device can operate stably.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible.

Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

Claims (10)

In the battery charging capacity correction method, Measuring the remaining capacity from the low charge state of the battery to the shutdown; And Correcting the first value of the battery from the full charge state to the low charge state to the charge capacity of the battery; Battery charging capacity correction method comprising a. The method of claim 1, The remaining capacity is, Counting the time from the low charge state of the battery to the shutdown; And calculating the battery capacity by multiplying the counted time by the voltage and current of the battery. The method of claim 1, When the battery starts charging without reaching a shutdown in the low charge state, the remaining capacity ratio from the low charge state to the shutdown multiplied by the previous battery charge capacity is reached from the full charge state to the low charge state. The method of claim 1, further comprising the step of correcting the second value plus the capacity of the battery to the charge capacity of the battery. The method of claim 3, And when the first value is greater than the second value, correcting the charging capacity of the battery according to the first value. In the battery charge correction device, A current sensing unit sensing a current of the battery; A voltage sensing unit sensing a voltage of the battery; A memory unit for storing a capacity from the fully charged state of the battery to the low charged state; Counting the time from the low charge state of the battery to the shutdown, multiplying the counted time by the current and voltage sensed by the current and voltage sensing unit to calculate the remaining capacity, A controller configured to correct the first value of the battery from the full charge state of the battery to the low charge state to the charge capacity of the battery; Battery charge capacity correction device comprising a. The method of claim 5, The control unit, When the battery starts charging without reaching a shutdown in the low charge state, the remaining capacity ratio from the low charge state to the shutdown multiplied by the previous battery charge capacity is reached from the full charge state to the low charge state. The battery charge capacity correction device, characterized in that for correcting the second value plus the capacity of the charge capacity of the battery. The method of claim 6, The control unit, And when the first value is greater than the second value, correcting the charging capacity of the battery according to the first value. In the battery discharge limit voltage correction method, Measuring the remaining capacity from the low charge state of the battery to the shutdown; And Correcting the discharge limit voltage of the battery with a discharge limit voltage stored in advance corresponding to the remaining capacity; Battery discharge limit voltage correction method comprising a. In the battery discharge limit voltage correction device, A current sensing unit sensing a current of the battery; A voltage sensing unit sensing a voltage of the battery; A memory unit configured to store a discharge limit voltage correction table corresponding to discharge capacity voltages corresponding to the capacity from the full charge state of the battery to the low charge state and a plurality of remaining capacity; Count the time from the low charge state of the battery to the shutdown, multiply the counted time and the current and voltage sensed by the current and voltage sensing unit to calculate the remaining capacity, and in the discharge limit voltage correction table A control unit that reads the discharge limit voltage corresponding to the calculated remaining capacity, and corrects the discharge limit voltage of the battery with the discharge limit voltage Battery discharge limit voltage correction device comprising a. The method of claim 9, The control unit, And if the remaining capacity does not exist in the discharge limit voltage correction table, obtaining a discharge limit voltage corresponding to the remaining capacity by interpolating the discharge limit voltage correcting device.

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