KR101549678B1 - Energy Management System reflecting battery capacity efficiency and method of the same - Google Patents

Abstract

The present invention is to provide a system and a method for more accurate and efficient energy management by calculating the state of charge (SOC) more accurately through digitizing power efficiency of an energy storage apparatus to calculate the SOC more accurately. An energy management system of the present invention incudes: a current measurement part for measuring a current flowing in a battery; a capacity efficiency calculation part which calculates a capacity efficiency value on the basis of the amplitude of inputted/outputted electricity which varies in proportion to the capacity of the battery; an SOC estimation part which estimates the SOC of the battery whose error is compensated by reflecting the current measured in the current measurement part and the capacity efficiency value calculated in the capacity efficiency calculation part; an energy loss calculation part which calculates energy loss by comparing the variation of energy inputted to the battery on the basis of the SOC estimated in the SOC estimation part with the variation of the actual SOC; a power value assignment part which assigns a power value by considering the energy loss calculated in the energy loss calculation part; and a storage part which provides the power value stored during charging/discharging of the battery by storing the power value assigned by the power value assignment part.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy management system and a battery management method,

The present invention relates to an energy management system and method considering charge / discharge efficiency when a plurality of batteries are charged / discharged. More particularly, the present invention relates to an energy management system and a method for accurately calculating a state of charge (SOC) The present invention relates to a system and method for more accurately and efficiently managing energy by calculating SOC more accurately.

As the rapid development of industry and economy has led to the rapid spread of electric appliances and electronic devices, there has been a demand for stable power supply and high quality electric power, so that uninterruptible power supply ; UPS) is increasing rapidly. Decrease in power quality due to instantaneous power failure, instantaneous voltage drop, and harmonics causes great economic loss to industry. In order to solve the problem of power quality, UPS, which is widely used in industry, has secured reliability for stable operation due to rapid development of power electronics technology. However, power quality deterioration due to failure of energy storage battery Often occurs.

Generally, as the battery is repeatedly charged and discharged, the performance is inevitably lowered, the service life is shortened, and the unstable characteristics of the battery cause a risk of accidents, resulting in a reduction in the overall reliability. Accordingly, a technology relating to a battery management system (BMS) for more efficiently using and managing a battery is also increasing in importance. In particular, the BMS must be able to accurately predict the state of health (SOH) of the battery in order to properly adjust the charge or discharge output of the battery and the strategy of using the state of charge (SOC).

However, since the BMS does not have a right to charge / discharge arbitrarily, it is difficult to calculate an accurate SOH.

Therefore, conventionally, the SOH of the battery is estimated using the capacity of the battery, the current of the battery, and the like. However, such a conventional method often includes a measurement error such as a capacity of a battery or a current of a battery. That is, the conventional SOC calculation for charging the battery is a method of accumulating and calculating the input and output power values in relation to the capacity. However, in this case, when the battery is charged / discharged at a high current, the coulombic efficiency is not 100%, so the charging becomes a little less and the discharging becomes a little more. will be.

This results in a reduction in the efficiency of the battery capacity since the reaction is terminated before the rate of the chemical response to transfer the electric power in the battery is slowed down to completion. Thus, the capacity efficiency of the battery becomes poor, and when the amount of energy used for the energy capacity is calculated, the SOC is lowered as much as the theoretical value is used.

Thus, there is a problem that estimation error may also occur in the estimated SOH. In order to solve such a problem, there is a problem that the battery management software needs to separately calculate SOC correction from time to time.

In addition, since hybrid batteries that are supplied to the market are cell-balanced so as to have the same charging / discharging speed, the same principle can be applied when charging. The larger the current of the input power, the faster the reaction speed does not follow the input speed of the power, and the efficiency of the capacity is not good, so that the SOC does not rise much even if the same power is injected.

Patent Document 10-2014-0053585: Apparatus and method for estimating battery remaining life

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to more accurately calculate SOC by calculating the power efficiency of an energy storage device to calculate a state of charge (SOC) And to provide a system and method for efficient energy management.

It is another object of the present invention to provide an energy management system and method for efficiently allocating power by applying a method of calculating an SOC indicating a state of energy charging of a battery.

In addition, other objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided an energy management system including a current measuring unit for measuring a current flowing in a battery, an input / output unit for changing input / output power proportional to a capacity of the battery, A capacity efficiency deriving unit for deriving a capacity efficiency value based on the size of the battery and a capacity efficiency value derived from the current measured by the current measuring unit and the capacity efficiency deriving unit, an energy loss calculation unit for calculating an energy loss by comparing a variation amount of energy put into the battery based on the SCO estimated by the SOC estimation unit with a change amount of the actual SOC, A power value assigning unit for assigning a power value in consideration of the energy loss calculated by the energy loss calculating unit; Save to save the power provided by the value stored in the battery during charging and discharging the power value may consists including parts.

Preferably, the current measuring unit is connected in series with the battery so as to periodically or non-periodically measure a charging / discharging current of the battery.

Preferably, the capacity efficiency deriving unit is a constant having a constant (K (P)) that reflects the battery capacity efficiency, a positive constant smaller than 1 in the case of discharging, and a constant greater than 1 in case of charging.

를 통해 용량 효율값(K(P))이 반영된 SOC를 추정하며, 이때, 상기 SOC(t)는 초기 SOC를 나타내며, 상기

는 시간당 배터리의 용량을 나타내는 에너지를 나타내며, 상기 K(P)는 용량 효율값을 나타내는 것을 특징으로 한다.Preferably, the SOC estimating unit calculates

(S (t)) represents an initial SOC in which the capacity efficiency value K (P) is reflected through the SOC

And K (P) represents a capacity efficiency value.

Preferably, the energy loss calculation unit compares the energy input to the battery with the estimated actual SOC to calculate an energy loss by a quadratic quadratic function.

Preferably, the power value assigning unit applies the energy loss calculated in the energy loss calculating unit to the required energy amount in the battery, allocates the required amount of power and sets the energy loss as an objective function, Scenario. ≪ / RTI >

According to an aspect of the present invention, there is provided an energy management method reflecting the charge / discharge efficiency of a battery according to the present invention includes the steps of: (A) periodically or non-periodically measuring a charging / discharging current of a battery flowing in a battery through a current measuring unit (B) calculating a capacity efficiency value based on a magnitude of input / output power that is changed in proportion to a capacity of the battery through a capacity efficiency deriving unit; and (C) Estimating a state of charge (SOC) of a battery whose error is compensated by reflecting the capacity efficiency value of the battery; (D) calculating a change amount of the energy input to the battery based on the SCO estimated through the energy loss calculating unit; Calculating an energy loss by comparing the amount of change in SOC with the amount of change in SOC; (E) (F) storing the allocated power value and charging / discharging through the stored power value at the time of charge / discharge of the battery And a step of performing the steps of:

Preferably, in the step (D), the energy loss is expressed by a quadratic quadratic function by calculating a formula (amount of energy input) - (amount of energy in which actual SOC is increased) = (energy loss).

Preferably, the power value allocated in the step (E) is set as the remaining time until the charging in consideration of the insufficient energy amount.

As described above, the energy management system and method reflecting the charge / discharge efficiency of the battery according to the present invention have the following effects.

First, by calculating the SOC in consideration of the chemical reaction characteristics and energy loss of the battery, the SOC error can be reduced, the correction value can be reduced, and the energy can be managed more accurately and efficiently.

Second, the conventional method of estimating the SOC through the simple accumulation of the current can measure the power and calculate the capacity efficiency in real time, which can contribute to the improvement of the life of the battery and the energy management of the battery, so that the system can be used more efficiently.

Third, if it is applied in simulations to implement a system using a battery or a battery management system, it can be usefully used in a system requiring a short-term energy storage device such as new and renewable energy. Thus, It can also be cost-effective for renewable energy users.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating the configuration of an energy management system that reflects charge / discharge efficiency of a battery according to an embodiment of the present invention; FIG.
2 is a flowchart for explaining an energy management method that reflects the charging / discharging efficiency of a battery according to an embodiment of the present invention.
3 is a graph showing an available energy amount graph according to the power consumption of the battery.
FIG. 4 is a graph showing the capacity efficiency of each vehicle based on the existing battery test report
5 (a) and 5 (b) are graphs showing the estimated SOC when the energy loss is not applied and when the energy loss is applied

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

A preferred embodiment of an energy management system and method reflecting the charging and discharging efficiency of the battery according to the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to let you know. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a configuration of an energy management system that reflects charge / discharge efficiency of a battery according to an embodiment of the present invention; FIG.

1, a current measuring unit 10 for measuring a current flowing in a battery, and a capacity efficiency deriving unit for deriving a capacity efficiency value based on the magnitude of input / output power that is changed in proportion to the capacity of the battery. A state of charge (SOC) of a battery whose error is compensated by reflecting a current measured by the current measuring unit 10 and a capacitance efficiency value derived from the capacitance efficiency deriving unit 20, And an energy loss calculation unit for calculating an energy loss by comparing the amount of change in energy input to the battery based on the SCO estimated by the SOC estimation unit 30 with the actual amount of change in SOC A power value allocator 50 for allocating a power value in consideration of an energy loss calculated by the energy loss calculator 40; and a power value allocator 50 for storing the power value allocated by the power value allocator 50 The stored power It consists of the storage unit 60 to provide a.

At this time, the current measuring unit 10 periodically or non-periodically measures the charging / discharging current of the battery. Generally, the current measuring unit 10 measures the current flowing in the battery and is connected in series with the battery. The current measuring unit 10 may be implemented in various forms. For example, the current measuring unit 110 can measure the current by sensing a voltage applied to a resistance provided on a current path. Also, the current measuring unit 10 may be implemented as a sensor installed to measure a current in a conventional battery cell pack. It will be apparent to those skilled in the art that various other current measuring instruments known in the art may be employed.

As shown in FIG. 3, the capacity efficiency deriving unit 20 is configured to reduce the calculation error of the estimated SOC since the efficiency of the capacity is varied according to the magnitude of the power. FIG. 3 is a graph showing the available energy amount according to the power consumption of the battery, and the battery is a graph of Volkswagen Jetta Hybrid SE having a capacity of 220V-5.0Ah 1100Wh. As shown in FIG. 3, the larger the power, the lower the available energy.

FIG. 4 is a graph showing the capacity efficiency of each vehicle based on the existing battery test report. As shown in FIG. 4, when charging / discharging with a small power, the constant converges to 1 and does not affect the calculation of the SOC. However, if the discharge power is large, the available capacity is decreased and more discharge is generated, and when the charge power is large, the capacity is increased and the charge is less.

Accordingly, the capacity efficiency deriving unit 20 expresses a constant (K (P)) reflecting the battery capacity efficiency by a cubic equation as shown in the following Equation (1). That is, a positive constant smaller than 1 in order to exhibit an effect that discharge is reduced due to a smaller capacity in the case of a discharge, and a constant greater than 1 is used so as to exhibit an effect of reducing the charging capacity by increasing the capacity in case of charging .

 Next, the SOC estimating unit 30 reflects the capacity efficiency value K (P) derived from the capacity efficiency deriving unit 20 to the existing SOC estimation formula to calculate the state of charge : SOC).

More specifically, as shown in the following Equation (2), the existing SOC estimation determines the SOC by accumulating the input / output power in proportion to the capacity of the battery.

는 시간당 배터리의 용량을 나타내는 에너지를 나타낸다.At this time, the SOC (t) represents the initial SOC,

Represents the energy representing the capacity of the battery per hour.

3, the capacity efficiency value K (P) derived from the capacity efficiency deriving unit 20 is expressed by Equation (2), as shown in the following Equation 3, since the capacity efficiency depends on the magnitude of the power, ), It is possible to reduce the calculation error of the SOC.

At this time, K (P) represents a capacity efficiency value.

The energy loss calculating unit 40 compares the energy input to the battery with the estimated actual SOC to calculate an energy loss. For example, when the battery is charged (amount of energy input) - (amount of energy in which the actual SOC is increased) = (energy loss) is set. In other words, the energy loss calculation unit 40 can express the energy loss as shown in Equation (4) through the calculation of Equations (2) and (3), and can be expressed as a quadratic quadratic function as shown in Equation (5) .

The power value allocator 50 applies the energy loss calculated by the energy loss calculator 40 to the charge / discharge scenario to the required energy amount in the battery.

More specifically, the power value to be allocated in real time to the charging power amount to be allocated to the battery is set to the remaining time until the charging in contrast to the insufficient amount of energy as shown in Equation (6).

At this time, in order to apply to the charging scenario, it is necessary to perform the charging in the direction of minimizing the allocation of the required amount of power and the energy loss as an objective function as shown in Equation (7).

The operation of the energy management system reflecting the charging and discharging efficiency of the battery according to the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals as those in Fig. 1 designate the same members performing the same function.

2 is a flowchart illustrating an energy management method that reflects a charge / discharge efficiency of a battery according to an embodiment of the present invention. In addition, the overlapping descriptions of the techniques described above are omitted.

Referring to FIG. 2, first, the charging / discharging current of the battery flowing through the battery is periodically or non-periodically measured through the current measuring unit 10 (S10).

The capacity efficiency value is calculated based on the magnitude of input / output power that is changed in proportion to the capacity of the battery through the capacity efficiency deriving unit 20 (S20). At this time, the capacity efficiency value K (P) can be expressed in cubic form as shown in Equation (1). That is, a positive constant smaller than 1 in order to exhibit an effect that discharge is reduced due to a reduced capacity in the case of a discharge, and a constant greater than 1 in order to exhibit an effect of reducing the charge and increasing the capacity in the case of charging.

Then, the state of charge (SOC) of the battery whose error is compensated is estimated by reflecting the measured current and the calculated capacity efficiency value through the SOC estimating unit 30 at step S30. In other words, the SOC of the battery whose error is compensated is estimated as Equation (3) by reflecting the derived capacity efficiency value K (P) to the existing SOC estimation equation shown in Equation (2).

Then, the energy loss is calculated by comparing the amount of change of the energy input to the battery based on the SCO estimated through the energy loss calculation unit 40 with the actual amount of change in the SOC (S40). In other words, the energy loss calculation unit 40 can express the energy loss as shown in Equation (4) through the calculation of Equations (2) and (3), and can be expressed as a quadratic quadratic function as shown in Equation (5) .

Then, the power value allocator 50 applies the energy loss calculated by the energy loss calculator 40 to the charge / discharge scenario to the required energy amount in the battery, thereby assigning the power value considering the calculated energy loss (S50). At this time, the power value to be allocated is set as the remaining time until the charging in contrast to the insufficient energy amount as shown in the following Equation (6). In order to apply to the charging scenario, as shown in Equation (7), charging is performed in the direction of minimizing the allocation of the required amount of power and the energy loss to the objective function.

Then, the power value assigned by the power value assigning unit 50 is stored in the storage unit 60, and then charged / discharged through the stored power value at step S60.

FIG. 5 (a) is a graph showing an estimated SOC when energy loss is not applied, and FIG. 5 (b) is a graph showing an estimated SOC when energy loss is applied.

As shown in FIG. 5 (a), the SOC increases more slowly when the same amount of power is allocated in the case of a conventional sonata having a large battery capacity, and only 77% can be charged while the other battery is charged up to 95% Respectively. It also applies all of the power to the charge, which consumes less time than is necessary.

On the other hand, as shown in FIG. 5 (b), in the present invention, when the optimization according to the set objective function is performed, two batteries are charged in the input time (within 30 minutes) It can be seen that the energy loss is less.

In this way, when the energy loss is considered, it is confirmed that the charging is completed within the time limit with less energy loss than the case without consideration. Also, even if the battery is charged within the same time, the battery can be prevented from leaning and charging can be performed in consideration of the life and stability of the battery, thereby increasing the life of the battery and saving energy.

This can constitute an electric vehicle battery charging scenario that is more efficient than normal power allocation through energy loss.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (11)

A current measuring unit for measuring a current flowing in the battery,
A capacity efficiency deriving unit for deriving a capacity efficiency value based on a magnitude of input / output power that is changed in proportion to a capacity of a battery;
An SOC estimator for estimating a state of charge (SOC) of a battery whose error is compensated by reflecting the current measured by the current measuring unit and the capacitance efficiency value derived from the capacitance efficiency deriving unit;
An energy loss calculation unit for calculating an energy loss by comparing a change amount of energy put into the battery based on the SCO estimated by the SOC estimation unit with a change amount of the actual SOC,
A power value allocator for allocating a power value in consideration of an energy loss calculated by the energy loss calculator;
And a storage unit for storing the power value allocated by the power value assigning unit and providing the stored power value when the battery is charged and discharged,
At this time, the power value allocator allocates the required energy amount of the battery to the required energy amount by applying the energy loss calculated by the energy loss calculating unit, and uses the charge / discharge Wherein the charge / discharge efficiency of the battery is reflected in the energy management system. The method according to claim 1,
Wherein the current measuring unit is connected in series with the battery to periodically or non-periodically measure a charging / discharging current of the battery. The method according to claim 1,
Wherein the capacity efficiency deriving unit is applied with a constant (K (P)) reflecting the battery capacity efficiency as a positive constant smaller than 1 in case of discharging and as a constant larger than 1 in case of charging. Reflected energy management system. The method according to claim 1,
The SOC estimation unit may calculate

And estimates the SOC reflecting the capacity efficiency value K (P)
At this time, the SOC (t) represents the initial SOC,

(P) represents an energy representing a capacity of a battery per hour, and K (P) represents a capacity efficiency value. The method according to claim 1,
Wherein the energy loss calculation unit compares the energy input to the battery with the estimated actual SOC to calculate an energy loss with a capacity efficiency loss proportional to a magnitude of power input and output from the battery. system. delete (A) measuring the charging / discharging current of the battery flowing in the battery through the current measuring unit periodically or non-periodically;
(B) calculating a capacity efficiency value based on a magnitude of input / output power that is changed in proportion to a capacity of the battery through a capacity efficiency deriving unit;
(C) estimating a state of charge (SOC) of a battery whose error is compensated by reflecting the measured current and the calculated capacity efficiency value through an SOC estimating unit;
(D) calculating an energy loss by comparing an amount of change in energy input to the battery based on the SCO estimated through the energy loss calculating unit with a change amount of the actual SOC,
(E) allocating a power value in consideration of an energy loss calculated by applying the calculated energy loss to a required energy amount in a battery through a charge / discharge scenario,
(F) storing the allocated power value, and advancing charge / discharge through a stored power value at the time of charge / discharge of the battery,
In the charging scenario application of the step (E), charging is performed in a direction that minimizes the allocation and the energy loss of the required amount of electric power as an objective function, and reflects the charging / discharging efficiency of the battery. 8. The method of claim 7,
Wherein the step (B) is a positive constant smaller than 1 in case of discharging and a constant larger than 1 in case of charging. Way. 8. The method of claim 7,
In the step (D), the energy loss is calculated by a formula (amount of energy input) - (amount of energy in which the actual SOC is increased) = (energy loss) and is expressed as a capacity efficiency loss proportional to the amount of power input / Wherein the charging / discharging efficiency of the battery is calculated based on the charging / discharging efficiency of the battery. 8. The method of claim 7,
Wherein the power value allocated in the step (E) is set to the remaining time until the charging in relation to the insufficient amount of energy. delete

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