KR102117316B1 - Device for Estimating Usable Capacity of Secondary Battery by Using CC/CV Ratio - Google Patents

Abstract

The present invention is an apparatus for estimating the usable capacity according to the life of the secondary battery, CC which is the ratio of the constant current (CC) maintenance time to the constant voltage (CV) maintenance time according to the number of charge / discharge cycles of the secondary battery A data storage unit storing data of / CV ratio values and available capacity data corresponding to the number of cycles; A measuring unit for measuring a constant voltage holding time and a constant current holding time between charging of the secondary battery to be measured; A first calculating unit for calculating a CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit; The CC / CV ratio value calculated by the first operation unit is compared with data of CC / CV ratio values stored in the data storage unit, and the number of cycles having a corresponding CC / CV ratio value and available capacity corresponding to the cycle number A second calculating unit that identifies data as the number of cycles and available capacity of the secondary battery to be measured; And a display unit that displays the number of cycles of the secondary battery to be measured, or an available capacity corresponding to the number of cycles, or the number of cycles and the available capacity.

Description

Device for Estimating Usable Capacity of Secondary Battery by Using CC / CV Ratio}

The present invention relates to an apparatus for estimating the available capacity of a secondary battery using a CC / CV ratio.

In recent years, the increase in the price of energy sources due to the exhaustion of fossil fuels, interest in environmental pollution is amplified, and the demand for eco-friendly alternative energy sources has become an indispensable factor for future life. Accordingly, research on various power generation technologies such as nuclear power, solar power, wind power, tidal power, and the like, and power storage devices for more efficient use of the produced energy are also attracting great interest.

In particular, as technology development and demand for mobile devices increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, many studies have been conducted on batteries that can meet various needs.

Typically, in the shape of the battery, the demand for a square secondary battery and a pouch-type secondary battery that can be applied to products such as a mobile phone with a small thickness is high, and in terms of material, it has advantages such as high energy density, discharge voltage, and output stability. There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

In addition, the secondary battery is classified according to the structure of the electrode assembly having a structure in which a separator interposed between the positive electrode, the negative electrode, and the positive electrode and the negative electrode is stacked. A jelly-roll type (winding type) electrode assembly with a structure wound in a state in which a separator is interposed, and a stacked (stacked) electrode assembly in which a plurality of positive and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween For example, recently, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, the electrode assembly of the advanced structure, which is a mixed form of the jelly-roll type and the stack type, has a predetermined unit. A stack / folding type electrode assembly having a structure in which the unit cells stacked with the anode and the cathode interposed with a separator positioned on a separation film and sequentially wound is developed.

In addition, according to the shape of the battery case, the secondary battery is a cylindrical battery and a square battery in which the electrode assembly is embedded in a cylindrical or square metal can, and a pouch-type battery in which the electrode assembly is embedded in a pouch-shaped case of an aluminum laminate sheet. Classified.

In particular, recently, a pouch-type battery having a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet has attracted much attention due to low manufacturing cost, small weight, and easy shape deformation. And its usage is gradually increasing.

In general, by measuring voltage and the like, the secondary battery checks the state of charge (SOC) of the secondary battery.

However, as the period of use of the secondary battery increases, in detail, as the number of charge / discharge cycles increases, the available capacity gradually decreases. When the available capacity decreases, the secondary battery has a faster SOC decrease rate. Lose.

Moreover, since the SOC represents only the relative state of charge of the secondary battery, the actual available capacity of the secondary battery, which gradually decreases as the number of charge / discharge cycles increases, cannot be accurately represented.

Therefore, as the period of use of the secondary battery increases, SOC alone cannot accurately predict or estimate the available capacity of the secondary battery, and accordingly, it is impossible to accurately predict a replacement time due to consumption of the secondary battery, and furthermore, the secondary battery Due to the rapid discharge of the device, problems such as suddenly becoming inoperable in a device using it as a power source may occur.

Therefore, there is a high need for a technology that can fundamentally solve these problems.

The present invention aims to solve the problems of the prior art as described above and the technical problems requested from the past.

The inventors of the present application, after repeated studies and various experiments, maintain a constant current (CC) for a constant voltage (CV) retention time according to the number of charge / discharge cycles of the secondary battery, as described later. By configuring to utilize the data of CC / CV ratio values, which are the ratio of time, it is possible to more accurately check the number of cycles or the life of the secondary battery and the available capacity according to the lifetime, thereby estimating an appropriate replacement time of the secondary battery. Since it is possible to effectively prevent problems due to inoperability of a device using the secondary battery as a power source, and to apply data of the CC / CV ratio values to various types of secondary batteries, the secondary battery is based on this. Regardless of the type, it was confirmed that the number of cycles and the available capacity could be more easily estimated and confirmed, and the present invention has been completed.

Apparatus for estimating the available capacity of the secondary battery according to the present invention for achieving the above object,

As a device for estimating the available capacity according to the life of the secondary battery,

Data of CC / CV ratio values that are the ratio of the constant current (CC) to the constant voltage (CV) retention time according to the number of charge / discharge cycles of the secondary battery and available capacity data corresponding to each cycle number A data storage unit storing therein;

A measuring unit for measuring a constant voltage holding time and a constant current holding time between charging of the secondary battery to be measured;

A first calculating unit for calculating a CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit;

The CC / CV ratio value calculated by the first operation unit is compared with data of CC / CV ratio values stored in the data storage unit, and the number of cycles having a corresponding CC / CV ratio value and available capacity corresponding to the cycle number A second calculating unit that identifies data as the number of cycles and available capacity of the secondary battery to be measured; And

A display unit for displaying the number of cycles of the secondary battery to be measured, the available capacity corresponding to the number of cycles, or the number of cycles and the available capacity;

It may be made of a structure comprising a.

Therefore, by utilizing the data of the CC / CV ratio values, it is possible to more accurately check the number of cycles or the life of the secondary battery and the available capacity according to the life, thereby estimating an appropriate replacement time of the secondary battery, It is possible to effectively prevent a problem due to inoperability of a device using the secondary battery as a power source.

In one specific example, as the number of charge / discharge cycles of the secondary battery increases, the constant voltage holding time may increase and the constant current holding time may decrease.

That is, as the number of charge / discharge cycles of the secondary battery increases, the constant voltage holding time and the constant current holding time may change in opposite directions. More specifically, while the constant voltage holding time increases, the constant current holding time decreases. Can be.

Accordingly, the CC / CV ratio value, which is the ratio of the constant current holding time to the constant voltage holding time, decreases as the number of charge / discharge cycles of the secondary battery increases, and based on this series of changes, the CC / CV ratio value If it has a smaller value, it can be more easily confirmed that the number of charge / discharge cycles is relatively large, meaning that the life of the secondary battery is small.

In addition, among the data of the CC / CV ratio values stored in the data storage unit, the second calculation unit is based on the number of cycles and the number of cycles having the CC / CV ratio value closest to the CC / CV ratio value calculated by the first calculation unit. It may be a structure that identifies the corresponding available capacity.

More specifically, the second operation unit may compare the CC / CV ratio value calculated by the first operation unit with data of CC / CV ratio values stored in the data storage unit.

At this time, if there is no CC / CV ratio value equal to the CC / CV ratio value calculated by the first calculation unit among the data of the CC / CV ratio values stored in the data storage unit, the second calculation unit is calculated by the first calculation unit The CC / CV ratio value closest to the CC / CV ratio value can be recognized as the CC / CV ratio value of the secondary battery to be measured, and the number of cycles having the adjacent CC / CV ratio value and the available number corresponding to the cycle number The capacity can be identified by the number of cycles and available capacity of the secondary battery to be measured.

Therefore, the CC / CV ratio value equal to the CC / CV ratio value calculated in the first calculation unit is not stored in the data storage unit, or the CC / CV calculated by factors such as the type of secondary battery to be measured or measurement conditions. Even if the ratio value has a predetermined error, among the data of the CC / CV ratio values stored in the data storage unit, the closest CC / CV ratio value is recognized as the CC / CV ratio value of the secondary battery to be measured, thereby secondary measurement target It is possible to more accurately estimate the number of cycles and the available capacity of the battery, while eliminating or minimizing the error of the estimation.

In one specific example, the data storage unit measures and calculates the CC / CV ratio data and cycles according to the number of charge / discharge cycles from the initial charge / discharge of the secondary battery to the completion of the life of the secondary battery. It may be a structure that stores available capacity data corresponding to the number of times.

Accordingly, the apparatus for estimating available capacity can more accurately estimate the number of cycles and available capacity of the secondary battery to be measured.

In another specific example, the data storage unit stores data and CC / CV ratio values according to the number of charging / discharging cycles having a predetermined interval from the time of the initial charging and discharging of the secondary battery to the completion of the life of the secondary battery. It may be a structure that stores available capacity data corresponding to the number of times.

More specifically, when the data storage unit stores data of CC / CV ratio values measured and calculated according to the number of charge / discharge cycles of the secondary battery and available capacity data corresponding thereto, the size of the data becomes excessively large. The cost required to configure the data storage unit may increase due to this, and the CC / CV ratio values stored in the data storage unit in the second calculation unit and the CC / CV ratio values calculated in the first calculation unit may be increased. By comparing the, there is a problem that it may take too much time to identify the number of cycles and the available capacity of the secondary battery to be measured.

Accordingly, the data storage unit stores data of CC / CV ratio values according to the number of charging / discharging cycles having a predetermined interval from the first charging / discharging of the secondary battery to the completion of the life of the secondary battery, and available capacity data corresponding thereto. By storing the bay, it is possible to effectively save the cost and time that may occur as the size of the data increases.

In this case, the available capacity estimation device,

Among the data of the CC / CV ratio values stored in the data storage unit, the second calculation unit selects the closest CC / CV ratio values with the CC / CV ratio value calculated in the first calculation unit therebetween, and selects the selected CC / CV ratio. Identify two cycle times each having values and two available capacities corresponding to the cycle times,

Further comprising a third operation unit for calculating the number of cycles corresponding to the CC / CV ratio value calculated by the first operation unit and the available capacity, based on the number of cycles and available capacity identified in the second operation unit And

The display unit may have a structure that displays the number of cycles calculated by the third calculation unit and the available capacity corresponding to the number of cycles as the number of cycles and the available capacity of the secondary battery to be measured.

In other words, among the data of the CC / CV ratio values stored in the data storage unit, the second calculation unit has 2 adjacent CC / CV ratio values calculated by the first calculation unit, respectively. By identifying the number of cycles and available capacity, and comparing the values with the CC / CV ratio value calculated in the first calculation unit through the third calculation unit, the number of cycles and the available capacity of the secondary battery to be measured are displayed on the display unit. Can be represented.

Therefore, while reducing the size of data stored in the data storage unit, it is possible to more accurately estimate the number of cycles and available capacity of the secondary battery to be measured.

Meanwhile, the CC / CV ratio value according to the number of charge / discharge cycles of the secondary battery may have an error range within ± 10% depending on the type of the secondary battery.

More specifically, the secondary battery may have different characteristics such as overall output, capacity, and energy density due to various factors such as the type and content of the active material used for the positive electrode and the negative electrode, or the size of the positive electrode and the negative electrode.

In this case, the various types of secondary batteries exhibit different behavior during charging and discharging, and more specifically, the constant voltage holding time and the constant current holding time according to the number of charge / discharge cycles of the secondary battery may be different.

However, in one secondary battery, the constant voltage holding time and the constant current holding time are changed relative to each other, and accordingly, the CC / CV ratio value which is the ratio of the constant current holding time to the constant voltage holding time according to the number of charge / discharge cycles of the secondary battery Silver may have the same or similar values regardless of the type of the secondary battery. More specifically, the CC / CV ratio value according to the number of charge / discharge cycles of the secondary battery is within ± 10% depending on the type of the secondary battery. It may have an error range of.

Therefore, the apparatus for estimating the available capacity of the secondary battery according to the present invention does not need to separately classify the available capacity data according to the life of each secondary battery according to the type of the secondary battery, and thus only the constant voltage holding time or constant current holding time Compared to the case of configuring data on the basis, the size of the data can be significantly reduced, and only the data stored in the data storage unit can be easily applied to the measurement of various secondary batteries, regardless of the type of the secondary battery.

In addition, the available capacity estimating device further includes a charge remaining amount calculation unit for calculating the remaining charge amount of the secondary battery to be measured based on the available capacity of the secondary battery to be measured,

The display unit may have a structure that further displays the calculated remaining amount of charge.

As described above, since the SOC of the secondary battery shows only a relatively charged state, the actual usable capacity of the secondary battery, which gradually decreases as the number of charge / discharge cycles increases, cannot be accurately represented. Accordingly, based on the available capacity, SOC It is not possible to accurately estimate the residual amount of charge of the secondary battery, which can be judged through.

On the other hand, the apparatus for estimating the available capacity of the secondary battery according to the present invention can more accurately estimate the actual usable capacity of the secondary battery based on the data stored in the data storage unit, and based on the available capacity, the secondary battery to be measured By further comprising a charge remaining amount calculation unit for calculating the charge remaining amount of, it is possible to more accurately and easily calculate or estimate the actual remaining charge amount of the secondary battery.

Therefore, since the actual charge remaining amount of the secondary battery that cannot be confirmed by conventional SOC alone can be easily estimated, the use plan or replacement time of the secondary battery can be more easily predicted.

In one specific example, the available capacity estimating device may be a structure built in the secondary battery charging and discharging device.

Therefore, in the process of charging and discharging the secondary battery by the charging and discharging device, the available capacity estimating device built in the charging and discharging device of the secondary battery estimates and displays the number of cycles of the secondary battery and the available capacity for the number of cycles. Since it is possible to do this, without a separate device, the life and available capacity of the secondary battery can be more easily confirmed in a routine charging and discharging process, and accordingly, an appropriate replacement time according to the life of the secondary battery can be more easily predicted. Therefore, it is possible to effectively prevent the sudden discharge of the secondary battery and the sudden inoperative state of the device.

However, if the available capacity estimating device is capable of more easily estimating the available capacity of the secondary battery, its configuration is not greatly limited, and in detail, conditions such as overall size can be applied to various secondary batteries. , It may be configured as a separate device, or considering the simplification of the configuration, the secondary battery itself may have a structure.

On the other hand, the present invention provides a method for estimating the available capacity according to the life of the secondary battery, the method comprising:

a) While charging and discharging the secondary battery to the maximum from the initial charge and discharge to the completion of the life of the secondary battery, the constant voltage holding time and constant current holding time according to the number of charge / discharge cycles are measured, and the calculated CC / Storing data of CV ratio values and available capacity data measured according to the number of cycles;

b) measuring the constant voltage holding time and constant current holding time of the secondary battery to be measured while performing charging of the secondary battery to be measured;

c) calculating the CC / CV ratio value using the measured constant voltage holding time and constant current holding time; And

d) Compare the calculated CC / CV ratio value with data of stored CC / CV ratio values, and measure the number of cycles having a corresponding CC / CV ratio value and available capacity data corresponding to the number of cycles to be measured. Identifying the number of cycles and the available capacity of the;

It may include.

In other words, the method for estimating available capacity of a secondary battery according to the present invention preferentially stores data of CC / CV ratio values according to the number of charge / discharge cycles of the secondary battery and available capacity data measured according to the number of cycles, and Based on the data, the CC / CV ratio value measured and calculated in the charging process of the secondary battery to be measured is compared with the data to identify and estimate the number of cycles of the secondary battery to be measured and available capacity data corresponding to the number of cycles can do.

Therefore, compared to the case of configuring data based only on the constant voltage holding time or the constant current holding time, the size of the data can be significantly reduced, and only the data stored in the data storage unit, regardless of the type of the secondary battery, various secondary It can be easily applied to the measurement of batteries.

In this case, the data of the CC / CV ratio values and available capacity data are measured and calculated according to the number of charge / discharge cycles from the initial charge / discharge of the secondary battery to the completion of the life of the secondary battery. It may be data of ratio values and available capacity data corresponding to the number of cycles.

Therefore, the number of cycles of the secondary battery to be measured and available capacity data corresponding thereto can be more accurately estimated.

In addition, the data of the CC / CV ratio values and the available capacity data, at a predetermined interval, from the initial charging and discharging of the secondary battery until the life of the secondary battery is completed, to minimize the overall size of the data. Of course, it may be data of CC / CV ratio values according to the number of charge / discharge cycles and available capacity data corresponding to the number of cycles.

At this time, the available capacity estimation method,

Among the data of the stored CC / CV ratio values, two cycles each having the selected CC / CV ratio values by selecting the closest CC / CV ratio values with the CC / CV ratio value of the secondary battery to be measured interposed therebetween. Identifying two available capacities corresponding to the number of times and the number of cycles; And

Based on the identified cycle times and available capacity, the number of cycles corresponding to the calculated CC / CV ratio value of the secondary battery to be measured and the available capacity corresponding thereto are calculated to calculate the cycle number and available capacity of the secondary battery to be measured. The process of identifying;

It may contain more.

Therefore, it is possible to effectively reduce the cost required as the size of the data increases.

In addition, the present invention provides a secondary battery system for estimating the available capacity according to the life of the secondary battery, wherein the secondary battery system,

A secondary battery capable of charging and discharging; And

A secondary battery management system for controlling charging and discharging of the secondary battery;

Including,

The secondary battery management system includes an available capacity estimation system that estimates usable capacity according to the life of the secondary battery by using charge / discharge characteristics of the secondary battery,

The available capacity estimation system stores data of CC / CV ratio values, which are the ratio of the constant current holding time to the constant voltage holding time according to the number of charge / discharge cycles of the secondary battery, and data that stores the available capacity data corresponding to each cycle number. Storage unit;

A measuring unit for measuring a constant voltage holding time and a constant current holding time between charging of the secondary battery to be measured;

A first calculating unit for calculating a CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit;

The CC / CV ratio value calculated by the first operation unit is compared with data of CC / CV ratio values stored in the data storage unit, and the number of cycles having a corresponding CC / CV ratio value and available capacity corresponding to the cycle number A second calculating unit that identifies data as the number of cycles and available capacity of the secondary battery to be measured; And

A display unit for displaying the number of cycles of the secondary battery to be measured, the available capacity corresponding to the number of cycles, or the number of cycles and the available capacity;

It may be a structure containing a.

That is, the secondary battery system itself includes an available capacity estimation system for estimating the available capacity according to the life of the secondary battery, so there is no need for a separate device for estimating the available capacity, and accordingly the cycle of the secondary battery The frequency and available capacity can be estimated more easily.

Since the specific configuration or structure of the secondary battery is known in the art, detailed description thereof will be omitted.

As described above, the apparatus for estimating the available capacity of a secondary battery according to the present invention is the ratio of the constant current (CC) retention time to the constant voltage (CV) retention time according to the number of charge / discharge cycles of the secondary battery By being configured to utilize data of the phosphorus CC / CV ratio values, it is possible to more accurately check the number of cycles or the life of the secondary battery and the available capacity according to the life, thereby estimating an appropriate replacement time of the secondary battery, It is possible to effectively prevent problems due to inoperability of a device using the secondary battery as a power source, and since data of the CC / CV ratio values can be applied to various kinds of secondary batteries, based on this, the type of the secondary battery is Regardless, it is possible to more easily estimate and confirm the number of cycles and available capacity.

1 is a schematic diagram schematically showing a configuration of an apparatus for estimating available capacity of a secondary battery according to an embodiment of the present invention;
2 is a schematic diagram schematically showing a configuration of an apparatus for estimating usable capacity of a secondary battery according to another embodiment of the present invention;
3 is a graph schematically showing a state of charge according to the number of charge / discharge cycles of a secondary battery measured to calculate data of CC / CV ratio values stored in the data storage unit of FIG. 2.

Hereinafter, the present invention is further described with reference to the drawings according to embodiments of the present invention, but the scope of the present invention is not limited thereto.

1 is a schematic diagram schematically showing a configuration of an apparatus for estimating a usable capacity of a secondary battery according to an embodiment of the present invention.

Referring to FIG. 1, the apparatus 100 for estimating available capacity of a secondary battery includes a measuring unit 110, a first calculating unit 120, a second calculating unit 130, a data storage unit 140, and a display unit 150. It contains.

The measuring unit 110 is electrically connected to the secondary battery 101 to be measured, and measures voltage and current according to the time between charging of the secondary battery 101 to be measured, thereby measuring constant voltage holding time and constant current holding time, respectively. do.

The first operation unit 120 is connected to the measurement unit 110 and calculates the CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit 110.

The second operation unit 130 is connected to the first operation unit 120 and the data storage unit 140.

The data storage unit 140 stores data of CC / CV ratio values according to the number of charge / discharge cycles of the secondary battery 101 to be measured and available capacity data corresponding to each cycle number.

The second operation unit 130 compares the CC / CV ratio value calculated by the first operation unit 120 with data of the CC / CV ratio values stored in the data storage unit 140 and compares the CC / CV ratio value corresponding thereto. The number of cycles and the available capacity data corresponding to the number of cycles are identified as the number of cycles and the available capacity of the secondary battery 101 to be measured.

At this time, the second calculation unit 130, among the data of the CC / CV ratio values stored in the data storage unit, the number of cycles having the CC / CV ratio value closest to the CC / CV ratio value calculated by the first calculation unit 120 and The available capacity corresponding to the number of cycles is identified by the number of cycles and the available capacity of the secondary battery to be measured.

The display unit 150 is connected to the second calculation unit 130, and the number of cycles of the secondary battery 101 to be measured identified by the second calculation unit 130 and the available capacity corresponding to the number of cycles are visually identified. Mark it as possible.

Accordingly, the user can easily check the life and usable capacity of the secondary battery 101 to be measured, based on the number of cycles and available capacity of the secondary battery 101 to be measured displayed on the display 150. It is possible to more accurately predict whether or not the secondary battery 101 to be measured is abnormal, or when to replace it, so that problems caused by rapid discharge of the secondary battery 101 to be measured can be effectively prevented.

2 is a schematic diagram schematically showing a configuration of an apparatus for estimating usable capacity of a secondary battery according to another embodiment of the present invention.

Referring to FIG. 2, the available capacity estimation apparatus 200 further includes a third calculation unit 260 and a charge residual amount calculation unit 270, compared to the available capacity estimation apparatus (100 in FIG. 1) of FIG. 1. .

First, the measurement unit 210 is electrically connected to the secondary battery 201 to be measured, and measures voltage and current according to the time between charging of the secondary battery 201 to be measured, thereby measuring the secondary battery 201 to be measured. Constant voltage holding time and constant current holding time are measured respectively.

The first operation unit 220 is connected to the measurement unit 210 and calculates the CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit 210.

The data storage unit 240 includes data of CC / CV ratio values according to the number of charge / discharge cycles having a predetermined interval and the number of cycles from the initial charge / discharge of the secondary battery 201 to be measured to the end of its life. Corresponding usable capacity data is stored.

The second calculation unit 230 is connected to the first calculation unit 220 and the data storage unit 240 and is calculated by the first calculation unit 220 among data of CC / CV ratio values stored in the data storage unit 240. Selecting the closest CC / CV ratio values with the CC / CV ratio values in between, identifying two cycle times each having the selected CC / CV ratio values and two available capacities corresponding to the cycle times do.

The third operation unit 260 is connected to the first operation unit 220 and the second operation unit 230, and based on the number of cycles and available capacities identified in the second operation unit 230, the first operation unit 220 The number of cycles corresponding to the calculated CC / CV ratio value and the available capacity corresponding thereto are calculated.

The charge residual amount calculation unit 270 is connected to the measurement unit 210 and the third calculation unit 260, and the voltage and current according to the time between charging of the secondary battery 201 to be measured measured by the measurement unit 210 The SOC representing the relative charging state is identified based on the same time, and the actual charge remaining amount is calculated through the SOC representing the relative charging state based on the available capacity calculated by the third calculator 260.

The display unit 250 is connected to the third calculation unit 260 and the charge residual amount calculation unit 270, and the secondary battery for measuring the number of cycles calculated by the third calculation unit 260 and the available capacity corresponding to the number of cycles The number of cycles in 201 and the available capacity are displayed, and the actual remaining amount of charge calculated by the remaining amount of charge calculation unit 270 is displayed so as to be visually identifiable.

3 is a graph schematically showing a state of charge according to the number of charge / discharge cycles of a secondary battery measured to calculate data of CC / CV ratio values stored in the data storage unit of FIG. 2.

Referring to FIG. 3 together with FIG. 2, the secondary battery is charged to a maximum charging voltage of about 4.35 V as the time between charges increases, and it is confirmed that the constant voltage holding time indicated by the flat straight section gradually increases as the number of cycles is accumulated. You can.

The inclined section of the graph represents the constant current holding section, and the flat straight section represents the constant voltage holding section.

The data of the CC / CV ratio values of the secondary battery and the available capacity data are data according to the number of cycles having a predetermined interval from the initial charging and discharging of the secondary battery until the life of the secondary battery is completed. It is indicated by specific values in 1.

division Constant current holding time (min) Constant current holding time (min) CC / CV ratio value Usable capacity (%) 1 cycle 105 49 2.13 100 300 cycles 88 64 1.38 90 500 cycles 73 75 0.97 81 600 cycles 8 93 0.08 29

As shown in Table 1 and FIG. 3, as the number of charge / discharge cycles increases in the secondary battery, the constant voltage holding time increases, the constant current holding time decreases, and accordingly, the ratio of the constant current holding time to the constant voltage holding time is CC / It can be seen that the CV ratio value gradually decreases.

In addition, it can be seen that as the number of charge / discharge cycles increases, the usable capacity also gradually decreases, and the decrease in the CC / CV ratio value and the decrease in available capacity are higher as the number of charge / discharge cycles of the secondary battery increases. It can be seen that it is rapidly increasing.

If, based on the constant voltage holding time and constant current holding time of the measurement target secondary battery 201 measured through the measurement unit 210, CC / CV of the measurement target secondary battery 201 calculated by the first operation unit 220 When the ratio value is' 118 ', the second operation unit is the number of two cycles having the CC / CV ratio values of the nearest' 138 'and' 97 'with' 118 'interposed therebetween,' 300 cycles' and ' The number of cycles of '500 cycles' is identified, and the corresponding available capacity of '90% 'and '81%' is identified.

Subsequently, the third calculation unit 260 includes the CC / CV ratio value '118' of the secondary battery 201 to be measured and the two CC / CV ratio values identified by the second calculation unit 230 '138' and ' Using the interval between 97 ', the number of cycles of the secondary battery 201 to be measured is approximately' 400 cycles ', which is an intermediate point, and it is proportionally calculated that the corresponding available capacity is approximately '86%'.

In addition, the charging residual amount calculation unit is the SOC representing the relative charging state based on the voltage and current according to the time between charging of the secondary battery 201 to be measured measured by the measuring unit 210 is identified as about '50% ' , Based on the available capacity '86% 'calculated by the third calculation unit 260, the actual charge remaining amount is calculated as about '43%' through the SOC representing the relative charging state.

Therefore, the available capacity estimating apparatus 200 is based on data of CC / CV ratio values according to the number of charge / discharge cycles having a predetermined interval and available capacity data corresponding to the number of cycles until the life of the secondary battery is completed. As a result, it is possible to easily estimate the number of cycles and available capacity of the secondary battery 201 to be measured, and more accurately calculate and estimate the actual remaining charge of the secondary battery 201 to be measured based on this.

Those of ordinary skill in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above.

Claims (14)

As a device for estimating the available capacity according to the life of the secondary battery,
Maintaining a constant current (CC) for a constant voltage (CV) retention time according to the number of charge / discharge cycles having a predetermined time interval from the time of the initial charging and discharging of the secondary battery to the completion of the life of the secondary battery A data storage unit that stores data of CC / CV ratio values which are a ratio of time and available capacity data corresponding to the number of cycles;
A measuring unit for measuring a constant voltage holding time and a constant current holding time between charging of the secondary battery to be measured;
A first calculating unit for calculating a CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit;
Among the data of the CC / CV ratio values stored in the data storage unit, selecting the closest CC / CV ratio values with the CC / CV ratio value calculated in the first operation unit therebetween, and selecting the selected CC / CV ratio values. A second operation unit for identifying two cycle times each having and two available capacity data corresponding to the cycle times;
Based on the number of cycles and the available capacity data identified in the second calculation unit, the interval between the two selected CC / CV ratio values is used to correspond to the number of cycles and the number of cycles of the secondary battery to be measured. A third calculation unit to calculate available capacity;
Based on the voltage and current according to the time between charges of the secondary battery to be measured measured by the measuring unit, the SOC indicating a relative charging state is identified, and the identified SOC is based on the available capacity calculated by the third calculating unit. A charge remaining amount calculation unit for calculating a substantial remaining charge amount of the secondary battery to be measured through; And
A display unit that displays the number of cycles of the secondary battery to be measured and the available capacity corresponding to the number of cycles calculated by the third calculation unit, and displays a substantial amount of charge remaining of the secondary battery to be measured calculated by the charging residual amount calculation unit ;
Apparatus for estimating usable capacity of a secondary battery comprising a. The apparatus for estimating usable capacity of a secondary battery according to claim 1, wherein as the number of charge / discharge cycles of the secondary battery increases, a constant voltage holding time increases and a constant current holding time decreases. delete delete delete delete The apparatus for estimating available capacity of a secondary battery according to claim 1, wherein the CC / CV ratio value according to the number of charge / discharge cycles of the secondary battery has an error range within ± 10%, depending on the type of the secondary battery. delete The apparatus for estimating the available capacity of a secondary battery according to claim 1, wherein the apparatus for estimating the available capacity is incorporated in a charging / discharging device of the secondary battery. As a method for estimating the available capacity according to the life of the secondary battery,
a) While charging and discharging the secondary battery from the first charging and discharging to the end of the life of the secondary battery, the constant voltage holding time and constant current holding time according to the number of charging and discharging cycles having a predetermined time interval are measured, and A process of storing data of CC / CV ratio values calculated using and available capacity data measured according to the number of cycles;
b) measuring the constant voltage holding time and constant current holding time of the secondary battery to be measured while performing charging of the secondary battery to be measured;
c) calculating the CC / CV ratio value using the measured constant voltage holding time and constant current holding time;
d) Among the data of the stored CC / CV ratio values, the number of two cycles each having the selected CC / CV ratio values is selected by selecting the closest CC / CV ratio values with the calculated CC / CV ratio value interposed therebetween. Identifying two available capacity data corresponding to fields and the number of cycles;
e) Based on the identified two cycle times and available capacity data, using the interval between the selected two CC / CV ratio values, the cycle number of the secondary battery to be measured and the available cycle number corresponding to the cycle number The process of calculating the capacity;
f) The SOC representing the relative state of charge is identified based on the voltage and current according to the time between charging of the measured secondary battery, and the identified SOC is based on the calculated available capacity of the secondary battery to be measured. Calculating a substantial remaining charge of the secondary battery to be measured through;
Method for estimating usable capacity of a secondary battery comprising a. delete delete delete A secondary battery capable of charging and discharging; And
A secondary battery management system for controlling charging and discharging of the secondary battery;
Including,
The secondary battery management system includes an available capacity estimation system that estimates usable capacity according to the life of the secondary battery by using charge / discharge characteristics of the secondary battery,
The usable capacity estimation system is the ratio of the constant current holding time to the constant voltage holding time according to the number of charging / discharging cycles having a predetermined time interval from the time of the initial charging and discharging of the secondary battery to the completion of the life of the secondary battery. A data storage unit storing data of / CV ratio values and available capacity data corresponding to the number of cycles;
A measuring unit for measuring a constant voltage holding time and a constant current holding time between charging of the secondary battery to be measured;
A first calculating unit for calculating a CC / CV ratio value using the constant voltage holding time and constant current holding time measured by the measuring unit;
Among the data of the CC / CV ratio values stored in the data storage unit, selecting the closest CC / CV ratio values with the CC / CV ratio value calculated in the first operation unit therebetween, and selecting the selected CC / CV ratio values. A second operation unit for identifying two cycle times each having and two available capacity data corresponding to the cycle times;
Based on the number of cycles and the available capacity data identified in the second calculation unit, the interval between the two selected CC / CV ratio values is used to correspond to the number of cycles and the number of cycles of the secondary battery to be measured. A third calculation unit to calculate available capacity;
Based on the voltage and current according to the time between charges of the secondary battery to be measured measured by the measuring unit, the SOC indicating a relative charging state is identified, and the identified SOC is based on the available capacity calculated by the third calculating unit. A charge remaining amount calculation unit for calculating a substantial remaining charge amount of the secondary battery to be measured through; And
A display unit that displays the number of cycles of the secondary battery to be measured and the available capacity corresponding to the number of cycles calculated by the third calculation unit, and displays a substantial amount of charge remaining of the secondary battery to be measured calculated by the charging residual amount calculation unit ;
Secondary battery system comprising a.

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