KR101852664B1 - Apparatus and method for measuring state of battery health - Google Patents

Abstract

The present invention relates to an apparatus and method for estimating the remaining battery life of a battery, and more particularly, A case setting unit for setting one or more cases by combining the sections; A determination unit for estimating an error value for each set case and designating a feature case for updating a state of health (SOH) of the battery; And an SOH estimating unit for estimating an SOH of the battery based on the specified characteristic case.

Description

[0001] Apparatus and method for measuring battery life [

The present invention relates to an apparatus and a method for estimating the remaining life of a battery (State Of Health: SOH), and more specifically, A case is set by combining the intervals, a case having the smallest error value is estimated by estimating the error value for each case set based on the measured battery data and the formula, ) Case, it is possible to reduce the possibility of errors in battery initial and final SOC estimation values according to variables such as the operating environment of the battery and the number of times of charging and discharging when calculating the amount of change in the state of charge (SOC) And more particularly, to an apparatus and method for estimating the remaining battery life of a battery that can accurately estimate the SOH of the battery.

Batteries having high electrical properties such as high energy density and high ease of application according to the product group are also referred to as accumulators or secondary batteries. In addition to the primary advantage of reducing the use of fossil fuels, there are no by- It is attracting attention as a new energy source for enhancing environmental friendliness and energy efficiency.

Therefore, the battery has been widely applied to an electric vehicle (EV) or an energy storage system (ESS) driven by an electric driving source as well as a portable device, and a battery management system Battery management system (BMS), battery balancing circuit, and relay circuit.

In particular, the BMS can manage the state of charge (SOC) of the battery, the state of health (SOH), the maximum input / output power allowable amount, and the output voltage using the state information of the battery, The technique of estimating the replacement time by predicting the lifetime of the battery is becoming a key technology in a more stable system operation.

Meanwhile, in the prior art for predicting the battery life, the SOH of the battery is estimated by using the ratio of current integration and SOC variation of the battery. When calculating the SOC change amount of the battery, there is a possibility that an error occurs in the battery initial and final SOC estimation values depending on the operating environment of the battery and the number of charge / discharge cycles.

Korean Patent Publication No. 10-2011-0084633

It is an object of the present invention to provide a battery charging method and a battery charging method in which one or more battery data is measured for each interval by designating a predetermined number of periods for charging and discharging the battery, And the case having the smallest error value is designated and utilized as a feature case for updating the state of health (SOH) of the battery, so that the remaining capacity Charging (SOC) In calculating the amount of change, it is possible to reduce the possibility of errors in the battery initial and final SOC estimation values according to variables such as the operating environment of the battery and the number of charging / discharging times, And to provide a life estimation apparatus and method.

The apparatus for estimating battery remaining life according to an embodiment of the present invention includes: a section designating unit for designating a time for charging and discharging a battery to a predetermined number of sections; A case setting unit for setting one or more cases by combining the sections; A determination unit for estimating an error value for each set case and designating a feature case for updating a state of health (SOH) of the battery; And an SOH estimating unit for estimating an SOH of the battery based on the specified characteristic case.

In one embodiment, the battery remaining life estimating apparatus further comprises a data collecting unit for measuring and storing one or more battery data for each of the designated intervals, Can be estimated.

In one embodiment, the one or more battery data may include a battery initial state of charge (SOC), a battery final SOC, an open circuit voltage (OCV) measurement method, or a Kalman filter The amount of change in SOC during battery charging or discharging, the amount of accumulated current during battery charging or discharging, the dormant period of the battery, and the temperature of the battery.

In one embodiment, the determining unit may substitute one or more battery data measured and stored in the data collecting unit into the following equation to estimate an error value for each case.

Here, SOH _previous = the remaining life of the battery measured _previously

dSOH = Remaining battery life with error value

segmentL = First section of the section included in the case to be assigned L

segmentM = the last section of the section included in the assignment case M

I = charge or discharge current of battery

SOC _initial = initial remaining capacity of battery in the first section of the section included in the substituted case

SOC _final = final remaining capacity of the battery in the final section of the section included in the assigned case

DELTA SOC = variation in the remaining capacity of the battery during charging or discharging

In one embodiment, the determination unit may designate a case having the smallest error value among the estimated case-by-case error values as a characteristic case for SOH update of the battery.

According to an aspect of the present invention, a battery is charged and discharged in a predetermined number of intervals, one or more battery data is measured for each interval, a case is set by combining intervals, A case having the smallest error value is estimated and utilized as a feature case for updating the SOH of the battery by estimating the error value for each case set based on the mathematical expression, and the state of charge (SOC) A battery remaining life estimating apparatus and method capable of estimating SOH of a battery with less possibility of error in battery initial and final SOC estimation values according to parameters such as battery operating environment and charge / can do.

1 is a schematic view of an electric vehicle to which an apparatus and method for estimating the remaining battery life according to an embodiment of the present invention can be applied.
FIG. 2 is a schematic view of a battery remaining life estimating apparatus according to an embodiment of the present invention. Referring to FIG.
FIG. 3 is a schematic diagram for explaining an interval designation and case setting method of the battery remaining life estimation apparatus according to an embodiment of the present invention.
4 is a flowchart illustrating a method of estimating battery remaining life according to an embodiment of the present invention.

The present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, a repeated description, a known function that may obscure the gist of the present invention, and a detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Further, the term "part" in the description means a unit for processing one or more functions or operations, which may be implemented by hardware, software, or a combination of hardware and software.

An electric vehicle described below refers to a vehicle that includes one or more electric motors as driving force. The energy used to propel the electric vehicle includes an electrical source such as a rechargeable battery and / or a fuel cell.

1 is a schematic view of an electric vehicle to which an apparatus and method for estimating the remaining battery life according to an embodiment of the present invention can be applied.

It should be noted that the device and method for estimating the remaining battery life according to an embodiment of the present invention can be applied to any technical field as long as the battery can be applied in addition to the electric vehicle 1. [

1, an electric vehicle 1 may include a battery 10, a battery management system (BMS) 20, an ECU (Electronic Control Unit) 30, an inverter 40 and a motor 50 have.

The battery 10 is an electric energy source that supplies a driving force to the motor 50 to drive the electric vehicle 1 and is driven by the inverter 40 in accordance with driving of the motor 50 and / May be charged or discharged.

Here, the type of the battery 10 is not particularly limited and may be a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel hydride battery, a nickel zinc battery, or the like.

The BMS 20 can manage the battery 10 by estimating the state of the battery 10. For example, the BMS 20 includes a battery remaining life estimating apparatus 100 (see FIG. 2) to calculate a change amount of state of charge (SOC) of the battery 10, , And estimates the remaining lifetime (SOH) of the battery 10 with higher reliability.

The ECU 30 is an electronic control device for controlling the state of the electric vehicle 1. For example, the ECU 30 can send a control signal to the inverter 40 based on state information such as SOH and SOC of the battery 10 delivered by the BMS 20. [

The inverter 40 can cause the battery 10 to be charged or discharged based on the control signal of the ECU 30. [

The motor 50 can drive the electric vehicle 1 based on control information (for example, torque information) transmitted from the ECU 30 using the electric energy of the battery 10. [

Since the above-described electric vehicle 1 is driven by using the battery 10, it is important to estimate the SOH of the battery 10 to efficiently operate the system.

Therefore, an apparatus and method for estimating the remaining battery life according to the present invention will be described with reference to FIGS. 2 to 4. FIG.

FIG. 2 is a schematic view of an apparatus 100 for estimating the remaining battery life according to an embodiment of the present invention.

2, an apparatus 100 for estimating the remaining battery life according to an exemplary embodiment of the present invention includes a section designating unit 110, a data collecting unit 120, a case setting unit 130, a determining unit 140, And an SOH estimation unit 150 as shown in FIG.

However, the battery remaining life estimation apparatus 100 shown in FIG. 2 is according to one embodiment, and the components thereof are not limited to the embodiment shown in FIG. 3, and some components may be added, changed Or deleted.

The interval designation unit 110 may designate a predetermined number of periods for charging and discharging the battery. The role of the section designator 110 and the process of designating the section will be described in more detail with reference to FIG.

FIG. 3 is a schematic diagram for explaining an interval designation and case setting method of the battery remaining life estimation apparatus according to an embodiment of the present invention.

For example, assuming that the charging and discharging time of the battery progresses eight times as shown in the graph shown in FIG. 3, the section designating unit 110 generates the discharging period 1 (111) to the discharging period 3 (113) The charging interval 3 116 and the discharging interval 4 117 through the discharging interval 5 118 can be designated in the same manner as described above. When the charging and discharging states of the battery are changed as described above, Can be reset and specified.

At this time, the initial SOC of the battery can be measured at the start point of each section, and the final SOC of the battery can be measured at the end point. For example, at the start point 111-1 of the discharge section 1 111, the start point 112-1 of the discharge section 2 112, the start point 114-1 of the charge section 1 114, The end point 111-2 of the discharge section 1 111 and the end point 112-2 of the discharge section 2 112 and the end point 114-2 of the charge section 1 114, Can be measured.

It should be noted that this section designation method is only an embodiment of the present invention, and the present invention is not limited thereto.

Referring back to FIG. 2, the data collecting unit 120 may measure and store one or more battery data for each designated interval.

At this time, the battery data to be measured and stored may include battery initial SOC, battery final SOC, open circuit voltage (OCV) measurement method or Kalman filter estimation method, A change amount of SOC during discharging, an accumulated amount of current during charging or discharging of the battery, a rest period of the battery, and a temperature of the battery.

For example, the current of the battery can be measured through a resistance measuring device, the SOC of the battery can be estimated by multiplying the charge and discharge current of the battery and multiplying the efficiency by the efficiency, And a method of contacting or directly connecting the sensor to the battery may be applied. It may also be desirable to measure the OCV after stabilization of the system for at least 30 minutes with the system in a stopped state, and the estimation through the Kalman filter may include an algorithm that minimizes the error covariance. However, the present invention is not limited thereto, and one or more battery data may be measured in various ways other than the above-described method.

The case setting unit 130 may perform a role of setting one or more cases by combining the sections designated by the section designating unit 110. [

Referring to FIG. 3 again, a case including a discharge interval 1 (111) includes a discharge interval 1 (111), a discharge interval 1 (111) to a discharge interval 2 (112), a discharge interval 1 111 to the discharge section 3 113, the discharge section 1 111 to the charge section 1 114, the discharge section 1 111 to the charge section 2 115, and the like. The case can be combined. The charging section 3 116, the charging section 3 through the discharging section 4 117, and the charging section 3 through the discharging section 5 118 may be combined with each other. have. As such, it is possible to combine the cases in which the eight assumed intervals are sequentially included on the basis of the respective intervals, and as a result, 36 cases can be set as a result. This case setting method is also according to one embodiment of the present invention, and the case can be set in various ways other than the above-described manner.

Referring back to FIG. 2, the determination unit 140 may assign the case set in the case setting unit 130 to the following equation to designate a feature case for SOH update of the battery .

&Quot; (1) "

Here, SOH _previous = the remaining life of the battery measured _previously

dSOH = Remaining battery life with error value

segmentL = First section of the section included in the case to be assigned L

segmentM = the last section of the section included in the assignment case M

I = charge or discharge current of battery

SOC _initial = initial remaining capacity of battery in the first section of the section included in the substituted case

SOC _final = final remaining capacity of the battery in the final section of the section included in the assigned case

DELTA SOC = variation in the remaining capacity of the battery during charging or discharging

At this time, each value to be substituted into the above equation is based on one or more battery data measured by the data collecting unit 120, and a different value can be assigned according to the interval included in each case to be substituted.

Accordingly, the determination unit 140 can estimate the error value for each case by calculating the equation, and designate the case having the smallest error value as the characteristic case for updating the SOH of the battery.

The SOH estimator 150 may perform a function of updating the previously measured SOH value of the battery based on the characteristic case designated by the determination unit 140. [

At this time, the previously measured SOH value of the battery may be a previously updated value by utilizing the characteristic case of the battery remaining life estimation apparatus according to an embodiment of the present invention, or may be a value before the characteristic case is designated by the determination unit 140 Lt; RTI ID = 0.0 > SOC < / RTI >

In the case of the first SOH estimated using the ratio of the current integration and the SOC change amount, the error amount accumulates as the SOC change amount is calculated, and the estimation accuracy deteriorates rapidly over time. It is possible to estimate the SOH of the battery with higher accuracy by updating the battery's previous SOH using the characteristic case designated in FIG. On the other hand, even if the previously measured SOH value of the battery is updated using the characteristic case, the SOH of the battery can be estimated more accurately through continuous updating.

4 is a flowchart illustrating a method of estimating battery remaining life according to an embodiment of the present invention.

Referring to FIG. 4, when starting the battery remaining life estimation method according to an embodiment of the present invention, the battery charging and discharging time is designated as a predetermined number of intervals (S410), and one or more battery data is measured (S420), and sets a case by combining the designated sections (S430). Subsequently, each case is substituted into a predetermined mathematical expression to measure a case-specific error value (S440), a case having the smallest error value is designated as a characteristic case (S450), and SOH (S460), thereby ending the battery remaining life estimation method according to an embodiment of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken as limitations. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: Battery remaining life estimating device
110:
120: Data collection unit
130: Case setting unit
140:
150: SOH estimation unit

Claims (10)

A section designating unit for designating a time for charging and discharging the battery to a predetermined number of sections;
A case setting unit for setting one or more cases by combining the intervals;
A determination unit for estimating an error value for each case and designating a feature case for updating the state of health of the battery;
An SOH estimator for estimating an SOH of the battery based on the specified characteristic case; And
And a data collection unit for measuring and storing one or more battery data for each of the designated intervals,
Estimating an error value for each case in the determination unit based on the data measured for each interval,
Wherein,
And one or more battery data measured and stored in the data collecting unit is substituted into the following equation to estimate an error value for each case:
Battery remaining life estimating device.
≪ Equation &

Here, SOH _previous = the remaining life of the battery measured _previously
dSOH = Remaining battery life with error value
segmentL = First section of the section included in the case to be assigned L
segmentM = the last section of the section included in the assignment case M
I = charge or discharge current of battery
SOC _initial = initial remaining capacity of battery in the first section of the section included in the substituted case
SOC _final = final remaining capacity of the battery in the final section of the section included in the assigned case
DELTA SOC = variation in the remaining capacity of the battery during charging or discharging delete The method according to claim 1,
Wherein the at least one battery data comprises:
(SOC), a battery final SOC, an open circuit voltage (OCV) measurement method or a Kalman filter estimation method for each of the designated sections, battery charging or charging, An amount of change of the SOC during discharging, an accumulated amount of the current during charging or discharging of the battery, a dormancy period of the battery, and a temperature of the battery.
Battery remaining life estimating device. delete The method according to claim 1,
Wherein,
And the case having the smallest error value among the estimated case-by-case error values is designated as the characteristic case for updating the SOH of the battery
Battery remaining life estimating device. Designating a time for charging and discharging the battery to a predetermined number of intervals;
Combining the intervals to set one or more cases;
Estimating an error value for each case and designating a characteristic case for SOH update of the battery;
Estimating an SOH of the battery based on the specified characteristic case; And
And measuring and storing one or more battery data for each of the designated intervals,
Estimating a case-specific error value in the step of designating a characteristic case for updating the SOH of the battery based on the measured data for each section,
Wherein the step of specifying a characteristic case for SOH update of the battery comprises:
And one or more battery data measured and stored in the data collecting unit is substituted into the following equation to estimate an error value for each case:
A method for estimating battery remaining life.
≪ Equation &

Here, SOH _previous = the remaining life of the battery measured _previously
dSOH = Remaining battery life with error value
segmentL = First section of the section included in the case to be assigned L
segmentM = the last section of the section included in the assignment case M
I = charge or discharge current of battery
SOC _initial = initial remaining capacity of battery in the first section of the section included in the substituted case
SOC _final = final remaining capacity of the battery in the final section of the section included in the assigned case
DELTA SOC = variation in the remaining capacity of the battery during charging or discharging delete The method according to claim 6,
Wherein the at least one battery data comprises:
A battery initial SOC, a battery final SOC, an OCV measurement method, or a Kalman filter estimation method, a change amount of SOC during battery charging or discharging, a cumulative amount of current during battery charging or discharging, And the temperature of the battery.
A method for estimating battery remaining life. delete The method according to claim 6,
Wherein the step of specifying a characteristic case for SOH update of the battery comprises:
And the case having the smallest error value among the estimated case-by-case error values is designated as the characteristic case for updating the SOH of the battery
A method for estimating battery remaining life.

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