KR101201110B1 - Charger of battery pack and charging method thereof - Google Patents

Abstract

The present invention relates to a charging apparatus and a method of a battery pack, and a technical problem to be solved is to lower the charging current according to the deterioration of the secondary battery so that the deterioration of the secondary battery is not accelerated further, and the life thereof is extended.

To this end, the gist of the solution according to the present invention receives a degree of battery degradation from a chargeable and dischargeable battery pack, and controls the controller to change the charge C-rate based on the received battery degradation degree, and control of the controller. By means of a signal, a charging device and method of a battery pack is disclosed, which comprises a charging current supply unit for supplying a charging current to the battery pack at the above-described modified charge seam rate.

Battery Packs, Charge Units, Degradation, Cycle Count, Full Charge Capacity (FCC), C-rate

Description

Charging device for battery pack and method thereof

1 is a graph illustrating charging characteristics of a general secondary battery.

2 is a graph illustrating capacity characteristics of a typical secondary battery according to cycle aging.

3 is a conceptual diagram illustrating a charging device for a battery pack according to the present invention.

4 is a block diagram showing a charging device for a battery pack according to the present invention.

5 is a flowchart illustrating a charging method of a battery pack according to the present invention.

6A and 6B are flowcharts illustrating a method of charging a battery pack according to the present invention.

Description of the Related Art

100; Battery pack 110; Secondary battery

120; AFE protection circuit 130; Micom

140; Current sensor 151; Charge switch

152; Discharge switch 200; Charging device

210; Voltage sensor 220; Current sensor

230; A controller 240; Charge current supply

P +, P-; Charge and discharge line Clock, Data; Communication lines

300; External system 400; AC plug

500; DC adapter

The present invention relates to a charging device and a method of a battery pack, and more particularly, by lowering the charging current according to the degree of deterioration of the secondary battery so that the deterioration of the secondary battery can not be further accelerated and its life can be extended. A charging device for a battery pack and a method thereof.

In general, a charging method of a lithium ion secondary battery or a lithium polymer secondary battery is known to be a constant current / constant voltage (CC-CV) charging method. In this constant current / constant voltage charging method, for example, as shown in FIG. 1, a constant voltage of 4.1 V or 4.2 V is set as a charging voltage, and the battery is charged at a constant current value until the voltage of the secondary battery reaches the set voltage. After reaching the set voltage, the charging current is reduced.

Here, expressions such as 1C, 2C and 0.5C are often used to indicate the current value of charge or discharge. For example, assuming that there is a secondary battery having a capacity of 1000mAh, when the battery is charged (or discharged) with a current of 1000mAh, 1C charging (or discharging, at this time, charging and discharging ends in 1 hour) is said. When charging (or discharging) at a current value of 2000 mAh, 2C charging (or discharging, at this time, charging and discharging ends), and when charging (or discharging) at 500 mAh current value, 0.5C charging (or discharging, 2 hours only) Charging and discharging ends). As described above, when the battery capacity is fully charged or discharged at a predetermined time, it will be described using the concept of C-rate. The c-rate is simply defined as the current capacity ratio per hour.

2, a capacity characteristic according to an increase in the number of charge / discharge cycles of a general secondary battery is illustrated. As shown, the lithium ion secondary battery gradually decreases the battery voltage and capacity as the charge and discharge cycle is repeated. Such a decrease in battery voltage and capacity is known to be caused by various impurities adhering to the battery negative electrode, ie, carbon, and the impedance increases according to the repetition of the charge / discharge cycle. For example, there are various other causes.

On the other hand, when charging a secondary battery in a conventional system (for example, a notebook computer, a mobile phone, other electronic products), regardless of the charge and discharge cycle or capacity degradation of the secondary battery at the initial set value (same C-rate) There is a tendency to charge the same. Most charging devices always have the same charge c-rate regardless of the charge / discharge cycles or capacity degradation of the secondary battery.

However, as described above, the secondary battery is said to decrease in battery capacity due to deterioration of the battery as the number of charge and discharge cycles increases. Thus, as the number of charge / discharge cycles increases, the rechargeable battery has a relatively high charge c-rate compared to the initial cycle.

That is, since the conventional secondary battery feels that the c-rate is relatively high as the number of charge / discharge cycles increases, the secondary battery deteriorates (that is, decreases in capacity). Here, when the c-rate is higher than the capacity of the secondary battery, degradation and capacity reduction of the secondary battery are further accelerated.

The present invention is to overcome the above-mentioned conventional problems, the object of the present invention is to lower the charging current according to the degree of deterioration of the secondary battery so that the deterioration of the secondary battery is not accelerated further, and the life can be extended A charging device for a battery pack and a method thereof are provided.

In order to achieve the above object, the battery pack charging device according to the present invention receives a degree of battery degradation from a chargeable / dischargeable battery pack, and changes the charge C-rate based on the received degree of battery degradation. And a charging current supply unit configured to supply a charging current to the battery pack at the changed charging sea rate by the control signal of the controller.

Here, the battery deterioration degree may be the number of charge and discharge cycles of the battery pack.

In addition, the controller may output a control signal to the charging current supply unit so that the charge seam rate decreases as the number of charge and discharge cycles increases.

In addition, the battery deterioration degree may be a full charge capacity (FCC) of the battery pack.

The control unit may output a control signal to the charging current supply unit such that the charge seam rate decreases as the full charge capacity (FCC) decreases.

In addition, the battery pack is connected to the charging current supply unit and the charging and discharging line, the secondary battery is charged to a predetermined capacity, and is connected to the secondary battery, detects the voltage of the secondary battery and converts it into digital data and outputs An analog front end (AFE) protection circuit and a microcomputer to obtain voltage information from the AFE protection circuit, to obtain current information through the charge and discharge line, calculate the degree of battery degradation and transmit to the controller.

In addition, the degree of battery degradation may be at least one of the number of charge and discharge cycles or a full charge capacity (FCC).

The battery pack may further include a charge / discharge switch installed in a charge / discharge line between the secondary battery and the charge current supply unit to block the charge / discharge path during overcharging or overdischarging of the secondary battery. When the secondary battery is overcharged or overdischarged, a charge / discharge stop signal is output to the protection circuit, so that the protection circuit can turn off the charge / discharge switch.

In addition, the control unit may be connected in parallel to the battery pack is connected to a voltage sensor for sensing the charging voltage of the battery pack, the current sensor is connected in series to the battery pack to detect the charging current of the battery pack may be further connected. have.

In addition, the method of charging the battery pack according to the present invention in order to achieve the above object is a step of receiving a deterioration of the battery from the battery pack, and the charge C-rate (C-rate) according to the deterioration degree of the received battery And a step of charging the battery pack with the changed charge C-rate.

Here, the degree of deterioration in the deterioration degree receiving step is the number of charge and discharge cycles of the battery, and in the step of changing the charge seam rate, the value is gradually changed to be lower than the initial charge seam rate as the number of charge and discharge cycles increases. Can be.

In addition, the degree of deterioration in the deterioration degree receiving step is a full charge capacity (FCC) of the battery, and in the step of changing the charge c-rate, the charge may be changed to be lower than the initial charge c-rate as the FCC decreases. have.

As described above, the battery pack charging device and method thereof according to the present invention prevent the battery from further deteriorating by lowering the charge seam rate as the battery pack progresses.

In other words, the present invention obtains the number of charge / discharge cycles or full charge capacity (FCC) of a battery pack, and charges the battery by lowering the charge seam rate as the number of cycles increases or the FCC decreases, thereby reducing the rate of degradation of the battery. Does not accelerate further. Of course, as the deterioration rate of the battery is reduced in this way, the life of the battery is further increased.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art may easily implement the present invention.

3 is a conceptual diagram illustrating a charging device for a battery pack according to the present invention.

As shown in FIG. 3, the present invention includes a battery pack 100 that can be charged and discharged, and a charging device 200 that charges the battery pack 100. Of course, the battery pack 100 and the charging device 200 are interconnected by charge and discharge lines (P +, P-), and are also interconnected by two communication lines (Clock, Data).

On the other hand, the charging device 200 may be installed as one component of the external system 300 normally. For example, it may be configured to charge the battery pack 100 by being provided with a charging device 200 therein while receiving a predetermined power from an external power source such as a notebook computer. Of course, the external system 300 includes an AC power plug 400 and a DC adapter 500 connected to the AC power plug 400 to supply DC power to the charging device 200 and a load (not shown). ) May be included.

4 is a block diagram showing a charging device for a battery pack according to the present invention.

As shown in FIG. 4, the charging device 200 according to the present invention includes a voltage sensor 210, a current sensor 220, a control unit 230, and a charging current supply unit 240.

The voltage sensor 210 is connected in parallel to the charge / discharge lines P + and P- of the battery pack 100 to detect the charging voltage of the battery pack 100, and the voltage information thus detected is controlled by the controller. Output to 230.

The current sensor 220 is connected in series to any one of the charge and discharge line (P +) of the battery pack 100, detects the charging current of the battery pack 100, and the current information detected in the control unit ( 230).

The controller 230 basically serves to control the charging current supply unit 240. In addition, the controller 230 is connected to the battery pack 100 by a communication line (Clock, Data). Therefore, the controller 230 receives predetermined information from the battery pack 100. Here, the predetermined information means the degree of deterioration (ie, the number of charge / discharge cycles, full charge capacity (FCC)), temperature, voltage, and current of the battery pack 100 to be described below. In addition, the control unit 230 receives the degradation level of the battery from the battery pack 100 to the communication line (Clock, Data) in order to achieve the object of the present invention, based on the received degradation degree of the battery To determine and change the new fill C-rate. Of course, the controller 230 outputs a predetermined control signal to the charging current supply unit 240 to charge the battery pack 100 with the newly changed charging sea-rate as described above. In addition, the control unit 230 may control the charging current supply unit 240 so that the battery pack 100 is constant current / constant voltage charging using the voltage sensor 210 and the current sensor 220 as in the related art.

The charging current supplying unit 240 serves to supply a predetermined charging current to the battery pack 100 at a predetermined charging seed rate according to a control signal of the controller 230. Of course, the charging current supply unit 240 may be connected to a DC adapter 500 for converting and supplying AC power to DC power.

The battery pack 100 includes a secondary battery 110, an analog front end (AFE) protection circuit 120, a microcomputer 130, a current sensor 140, and a charge / discharge switch 151, 152. It can be made, including).

The secondary battery 110 is a battery that can be charged and discharged at a predetermined capacity by being connected to the charging current supply unit 240 and the charge / discharge lines P + and P-. For example, the secondary battery 110 may be any one selected from a lithium ion secondary battery, a lithium polymer secondary battery, or an equivalent thereof, but is not limited thereto.

The AFE protection circuit 120 is connected to the secondary battery 110 in parallel, and serves to detect the voltage of the secondary battery 110, convert it into digital data, and output the digital data to the microcomputer 130. In addition, the AFE protection circuit 120 may turn on or off the charge / discharge switches 151 and 152 by receiving a predetermined control signal from the microcomputer 130.

The microcomputer 130 obtains voltage information of the secondary battery 110 from the AFE protection circuit 120 and calculates a degree of deterioration of the secondary battery 110 by obtaining current information from the current sensor 140. That is, the charge / discharge voltage and the charge / discharge current of the secondary battery 110 are obtained, and the number of charge / discharge cycles and the full charge capacity (FCC) of the secondary battery 110 are calculated by using the same. Of course, the degree of degradation calculated as described above is transmitted to the controller 230 of the charging device 200 through the communication line (Clock, Data). In addition, the microcomputer 130 uses the voltage information of the secondary battery 110 obtained from the AFE protection circuit 120 and current information obtained from the current sensor 140 to determine whether the secondary battery 110 is currently in an overcharged state or an overdischarge state. It is determined whether the state, and outputs a predetermined control signal to the AFE protection circuit 120. That is, the microcomputer 130 stops charging and discharging to stop charging and discharging of the secondary battery 110 through the charge / discharge lines P + and P- when the secondary battery 110 is determined to be in an overcharge or overdischarge state. The signal is output to the AFE protection circuit 120.

The current sensor 140 outputs voltage information applied to the microcomputer 130 to allow the microcomputer 130 to calculate the charge / discharge current flowing through the charge / discharge line P−.

The charge / discharge switches 151 and 152 may be formed of the charge switch 151 and the discharge switch 152 again. The charge switch 151 is turned off by the AFE protection circuit 120 when the secondary battery 110 is in an overcharge state. In addition, the discharge switch 152 is turned off by the AFE protection circuit 120 when the secondary battery 110 is in an over discharge state or an over discharge current state. The charge switch 151 and the discharge switch 152 may basically be a power MOSFET having a parasitic diode, but the type of the device is not limited thereto.

Meanwhile, the degree of deterioration of the secondary battery 110, that is, the number of charge / discharge cycles or the FCC may be calculated in various ways.

For example, when the number of charge and discharge cycles is charged to 90% or more of the initial capacity or discharged to 90% or less, a method of increasing cycle 1 may be used. In addition, since the user does not repeatedly use the secondary battery 110 in a fully charged and a fully discharged state and randomly charges and discharges the user, the total accumulated charge amount or the total accumulated discharge amount reaches an initial capacity or 90% thereof. If so, a method of increasing cycle 1 may be used. In addition, the FCC accumulates the charge capacity until fully charged, or accumulates and calculates the discharge capacity until fully discharged the fully charged battery, thereby calculating the previous full charge capacity with the calculated full charge capacity. The method of correction can be used. Regardless of which calculation method is used, the method for calculating the number of charge / discharge cycles or the FCC is already well known to those skilled in the art of the smart battery industry, and thus the detailed description thereof will be omitted.

5 is a flowchart illustrating a charging method of a battery pack according to the present invention.

In the following description, the operation of the control unit 230 of the charging device 200 will be described.

As shown in FIG. 5, the charging method of the battery pack according to the present invention includes receiving a degree of degradation of the battery pack from the battery pack (S51), and determining and changing the charge seam rate according to the degree of degradation of the battery. (S52), and the step (S53) for charging the secondary battery with the modified charge sea-rate.

The degree of deterioration may be the number of charge / discharge cycles of the secondary battery 110 or the FCC of the secondary battery 110. In addition, the charge C-rate may be a function set to have a smaller value as the number of charge and discharge cycles increases, and may be a function set to have a smaller value as the FCC becomes smaller.

6A and 6B are flowcharts illustrating in more detail a method of charging a battery pack according to the present invention.

First, as shown in FIG. 6A, the present invention includes the steps of receiving the number of cycles from the battery pack (S61_a), determining and changing the charge seed rate according to the number of cycles of the battery (S62_a), and the changed charging. The secondary battery may be charged with c-rate (S63_a).

As described above, the number of cycles of the battery is calculated by the microcomputer 130 of the battery pack 100 obtaining the charge / discharge voltage information from the AFE protection circuit 120 and the charge / discharge current information from the current sensor 140. . For example, the number of charge and discharge cycles may be a value that increases once when the battery capacity is charged at 90% or more relative to the initial capacity, or discharged below 90%. Of course, the user may use the battery pack 100 after being fully charged and then fully discharged, or may have a pattern of repeatedly using the charging and discharging at random. However, in any pattern, if the total cumulative discharge amount discharged from the secondary battery 110 is less than 90% of the initial capacity, the charge and discharge cycle information is always accurately calculated by calculating it as one cycle increase.

The charge and discharge cycle information calculated in this way is received from the microcomputer 130 of the battery pack 100 through the communication line (Clock, Data) to the control unit 230 of the charging device 200 (S61_a).

Subsequently, the controller 230 of the charging device 200 determines and changes the charging sea-rate according to the number of cycles (S62_a).

The charge C-rate is a value set to a value that decreases as the number of charge and discharge cycles increases as described above. Of course, the number of charge-discharge cycles versus the number of charge-discharge cycles is tabled and stored in the internal memory of the controller 230. Therefore, the controller 230 changes the existing charge seam rate by reading the charge seam rate corresponding to the number of charge / discharge cycles.

Finally, the controller 230 charges the secondary battery 110 with the changed charge seam rate (S63_a). That is, the controller 230 outputs a predetermined control signal to the charge current supply unit 240. In addition, the charging current supplying unit 240 supplies the charging current having the changed charge seam rate to the secondary battery 110 of the battery pack 100 as described above.

In this manner, the present invention reduces the battery capacity as the number of charge / discharge cycles of the secondary battery 110 increases, thereby appropriately reducing the charge c-rate so that the deterioration of the battery is not accelerated. Therefore, in the charging method according to the present invention, the battery is charged with a charge C-rate appropriate to the battery capacity, so that battery deterioration is not accelerated, and accordingly, the life of the battery is increased.

Next, as shown in FIG. 6B, the present invention includes receiving the FCC from the battery pack (S61_b), determining and changing the charge seam rate according to the FCC of the battery (S62_b), and the modified charging. The secondary battery may be charged with the c-rate (S63_b).

Here, as described above, the FCC of the battery allows the microcomputer 130 of the battery pack 100 to obtain charge and discharge voltage information from the AFE protection circuit 120 and to obtain and calculate charge and discharge current information from the current sensor 140. do. The FCC can be calculated in a number of ways, for example by calculating the charge capacity until fully charged or by calculating the total discharge capacity until the battery is fully discharged. We revise last full charge capacity with full charge capacity that became. Of course, by this calculation, the FCC gradually decreases.

The FCC information calculated as described above is received from the microcomputer 130 of the battery pack 100 through the communication line (Clock, Data) to the controller 230 of the charging device 200 (S61_b).

Subsequently, the controller 230 of the charging device 200 determines and changes the charging sea-rate according to the FCC (S62_b).

The charge c-rate is a value set to a value that decreases as the FCC decreases as described above. Of course, the charge c-rate compared to the FCC is stored in the internal memory of the controller 230 is a table. Therefore, the controller 230 changes the existing charge c-rate value by reading the charge c-rate value corresponding to the FCC.

Finally, the controller 230 charges the secondary battery 110 with the changed charge seam rate (S63_b). That is, the controller 230 outputs a predetermined control signal to the charge current supply unit 240. In addition, the charging current supplying unit 240 supplies the charging current having the changed charge seam rate to the secondary battery 110 of the battery pack 100 as described above.

As such, the present invention reduces the battery capacity as the FCC decreases, thereby reducing the charge seam rate so that the degradation of the battery is not accelerated. Therefore, in the charging method according to the present invention, the battery is charged with a charge C-rate appropriate to the battery capacity, so that battery deterioration is not accelerated, and accordingly, the life of the battery is increased.

As described above, the battery pack charging device and method thereof according to the present invention has an effect of preventing the phenomenon of further deterioration of the battery by lowering the charge seam rate as the battery pack progresses.

In other words, the present invention obtains the number of charge / discharge cycles or full charge capacity (FCC) of a battery pack, and charges the battery by lowering the charge seam rate as the number of cycles increases or the FCC decreases, thereby reducing the rate of degradation of the battery. Is effective to prevent further acceleration. Of course, as the deterioration rate of the battery is reduced in this way, the life of the battery is further increased.

What has been described above is only one embodiment for carrying out the charging apparatus and method of the battery pack according to the present invention, the present invention is not limited to the above-described embodiment, as claimed in the following claims Without departing from the gist of the present invention, anyone of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (12)

A control unit which receives a degree of battery degradation from the battery pack prior to charging the chargeable / dischargeable battery pack and changes a charge C-rate based on the received battery degree of degradation; A battery pack comprising a charging current supply unit configured to supply a charging current to the battery pack at the changed charging sea rate by the control signal of the controller after the charging seam rate is changed by the control unit Charging device. The battery pack charging device according to claim 1, wherein the battery deterioration degree is a number of charge and discharge cycles of the battery pack. The charging apparatus of claim 2, wherein the controller outputs a control signal to the charging current supply unit so that the charge seam rate decreases as the number of charge and discharge cycles increases. The battery pack charging device according to claim 1, wherein the battery deterioration degree is a full charge capacity (FCC) of the battery pack. 5. The apparatus of claim 4, wherein the controller is configured to output a control signal to the charge current supply unit such that the charge seam rate decreases as the full charge capacity (FCC) decreases. 6. The method of claim 1, wherein the battery pack A secondary battery charged with a predetermined capacity by being connected through the charging current supply unit and a charge / discharge line; An analog front end (AFE) protection circuit connected to the secondary battery for sensing a voltage of the secondary battery, converting the secondary battery into digital data, and outputting the digital data; And a microcomputer that obtains voltage information from the AFE protection circuit, obtains current information through the charge / discharge line, calculates a degree of battery deterioration, and transmits it to the controller. The apparatus of claim 6, wherein the battery deterioration degree is at least one of a number of charge and discharge cycles or a full charge capacity (FCC). The method of claim 6, wherein the battery pack A charge / discharge switch installed on a charge / discharge line between the secondary battery and the charge current supply unit and blocking the charge / discharge path during overcharge or overdischarge of the secondary battery, And the micom outputs a charge / discharge stop signal to the protection circuit when the secondary battery is overcharged or overdischarged, so that the protection circuit turns off the charge / discharge switch. The method of claim 1, wherein the control unit A battery sensor connected in parallel with the battery pack to detect a charging voltage of the battery pack, and a battery sensor further connected to the battery pack in series to detect a charging current of the battery pack Charging device. Receiving a degree of deterioration of the battery from the battery pack prior to charging the battery pack, Changing the charge C-rate according to the degree of deterioration of the received battery; Charging the battery pack with the changed charge c-rate after the charge c-rate is changed. The method of claim 10, wherein the degree of deterioration in the deterioration degree receiving step is a number of charge and discharge cycles of the battery, and in the step of changing the charge seam rate, it is gradually lower than the initial charge seam rate as the number of charge and discharge cycles increases. Charging method of a battery pack, characterized in that changed to a value. 11. The method of claim 10, wherein the degree of deterioration in the degree of deterioration is a full charge capacity (FCC) of the battery, and in the step of changing the charge c-rate, a value gradually lower than the initial charge c-rate as the FCC decreases. Charging method of a battery pack, characterized in that changed to be.

Images