WO2022186524A1 - Energy storage type charger/discharger for secondary battery, and method for charging/discharging secondary battery by using same - Google Patents

Abstract

The present invention relates to an energy storage type charger/discharger for a secondary battery, and a method for charging/discharging a secondary battery by using same. Since the discharge energy of a secondary battery is stored through an energy storage part and is used as charging energy, energy efficiency can be improved, and application to a secondary battery formation process and the like is possible.

Description

Energy storage type secondary battery charging/discharging device and secondary battery charging/discharging method using the same

This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0027487 dated March 2, 2021, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.

The present invention relates to an energy storage type secondary battery charging/discharging device and a secondary battery charging/discharging method using the same.

As the demand for portable electronic products such as laptops and mobile phones is rapidly increasing and the development of electric vehicles, energy storage batteries, robots, satellites, etc. is in full swing, research on high-performance secondary batteries that can be repeatedly charged and discharged is actively conducted. is becoming

The secondary battery may be used in the form of a single secondary battery or in the form of a module or pack in which a plurality of secondary batteries are electrically connected, depending on the type of external device in which it is used. For example, while a small device such as a mobile phone can operate for a predetermined time with a relatively low level of output and capacity, a power source such as an electric vehicle or a hybrid electric vehicle or a medium or large device such as a large-capacity energy storage device requires a high level of output and capacity.

In general, in the process of manufacturing the secondary battery, an activation process for the secondary battery is performed. In the activation process, a charging/discharging process for the secondary battery is required. Alternatively, in the evaluation process of the manufactured secondary battery, repeated charging and discharging processes are required. In the charging/discharging process, there is a problem in that a large amount of energy is consumed in this process.

Specifically, FIG. 1 is a schematic diagram exemplarily showing a conventional charger/discharger. Referring to FIG. 1 , the conventional charger/discharger 10 receives power from an external power source 20 to charge a secondary battery 30 , and the charged secondary battery 30 is discharged through a coil resistor 15 . will perform Specifically, when the AC power of the external power source 20 is supplied through the power supply unit 11 to the charger/discharger 10 , the converter 12 converts it into DC power. The converted DC power is supplied to the secondary battery 30 to be charged and discharged through the control unit 13 . At this time, the charger/discharger terminal portions 14(a) and 14(b) and the secondary battery terminal portions 31 and 32 are electrically connected to each other. When the secondary battery 30 is discharged, the electric energy charged in the secondary battery 30 is supplied to the coil resistor 15 , and the electric energy supplied from the coil resistor 15 is consumed.

Therefore, there is a high need for a technology capable of minimizing the energy consumed in the charging/discharging process of the secondary battery and recycling it.

In order to solve the problems of the prior art as described above, the present invention is to provide an energy storage unit built-in charger/discharger that stores the discharge energy of a secondary battery and utilizes it as charging energy, and a secondary battery charging/discharging method using the same.

In order to solve the above problems, the present invention provides an energy storage unit built-in charger/discharger. In one example, the charger and discharger according to the present invention, a power supply for supplying electrical energy from the outside; a terminal part electrically connected to the power supply part and in electrical contact with a secondary battery to be charged/discharged; an energy storage unit electrically connected to the terminal unit and storing electrical energy; and a control unit electrically connected to the power supply unit, the terminal unit, and the energy storage unit, respectively, to control charging and discharging modes thereof. In addition, the charger/discharger (i) charges the secondary battery using at least one of the power supply unit and the energy storage unit as a power source in the charging mode, and (ii) charges the energy storage unit using the charged secondary battery as a power source in the discharging mode do.

In another example, the power supply unit supplies AC power and is located between the power supply unit and the terminal unit, and includes a converter for converting AC power supplied from the power supply unit into DC power.

In a specific example, in the charging mode, the controller primarily charges the secondary battery through the energy storage unit and secondary charges the energy storage unit through the power supply unit.

In another specific example, in the charging mode, the control unit charges the secondary battery by SOC a% through the energy storage unit, and charges the secondary battery by SOC b% through the power supply unit, but the ratio of a to b (a/ b) ranges from 2 to 50, and the sum of a and b ranges up to 100.

In a specific example, in the discharge mode, the efficiency of energy stored in the energy storage unit compared to the discharge amount of the secondary battery of the charger/discharger is 80% or more.

In one specific example, the energy storage unit is a battery energy storage system (BESS).

In addition, the present invention provides a secondary battery charging/discharging method using the above-described energy storage built-in charging/discharging device.

In one example, a secondary battery charging/discharging method according to the present invention includes the steps of charging a secondary battery to be charged and discharged; and discharging the charged secondary battery. Specifically, in the step of charging the secondary battery, the secondary battery is charged by using at least one of a power supply unit and an energy storage unit as a power source, and in the step of discharging the secondary battery, energy using the charged secondary battery as a power source Charge the storage unit.

In a specific example, in the charging of the secondary battery, the secondary battery is charged by SOC a% using the energy storage unit as a power source, and the secondary battery is charged by SOC b% by using the power supply unit as a power source, but a The ratio (a/b) ranges from 2 to 50.

In a more specific example, in the step of charging the secondary battery, the power supply supplies AC power, and through a converter, further comprising a conversion step of converting AC power supplied from the power supply to DC power through a converter, The storage unit supplies DC power and charges the secondary battery without a separate conversion step.

In another example, the secondary battery charging/discharging method according to the present invention is performed in any one or more processes of a secondary battery activation process and a charging/discharging test for a secondary battery.

In addition, the present invention provides another type of charging/discharging method of a secondary battery through the above-described energy storage built-in charger and discharger.

In one example, the secondary battery charging/discharging method according to the present invention determines a charging or discharging mode for a secondary battery to be charged/discharged through a control unit, (a) in the charging mode, the charge amount SOC of the preset energy storage unit Based on x%, when the charge amount of the energy storage unit is SOC x% or more, the secondary battery is charged using the energy storage unit as a power source. The secondary battery is charged using only the supply unit as a power source, where x is in the range of 0 to 50, and (b) in the discharging mode, energy discharged from the secondary battery is stored in the energy storage unit.

In one example, in the secondary battery charging/discharging method according to the present invention, in the discharging mode, the energy discharged from the secondary battery is stored in the energy storage unit, and the charge capacity of the energy storage unit is 90% of the discharge capacity of the secondary battery or its More than that.

In a specific example, the secondary battery charging/discharging method is performed in any one or more processes of a secondary battery activation process and a secondary battery charging/discharging test.

The charging/discharging device and the secondary battery charging/discharging method using the same according to the present invention can increase energy efficiency by storing the discharge energy of the secondary battery and using it as the charging energy, and can be used in the activation process of the secondary battery.

1 is a schematic diagram showing a conventional charger/discharger.

2 is a schematic diagram showing a charger/discharger according to an embodiment of the present invention.

3 and 4 are schematic diagrams showing a charging mode or a discharging mode of the charger/discharger according to an embodiment of the present invention, respectively.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present invention, terms such as "comprises" or "have" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

The present invention provides an energy storage type charger/discharger, which has a structure including or incorporating an energy storage unit. In one embodiment, the charger and discharger according to the present invention, a power supply for supplying electrical energy from the outside; a terminal part electrically connected to the power supply part and in electrical contact with a secondary battery to be charged/discharged; an energy storage unit electrically connected to the terminal unit and storing electrical energy; and a control unit electrically connected to the power supply unit, the terminal unit, and the energy storage unit, respectively, to control charging and discharging modes thereof. The control unit switches and controls the charger/discharger to a charging mode or a discharging mode. Specifically, in the charger and charger according to the present invention, (i) in the charging mode, any one or more of the power supply unit and the energy storage unit is used as a power to charge the secondary battery, and (ii) in the discharging mode, the charged secondary battery is used as a power source to charge the energy storage unit.

In the charging mode, the energy storage unit alone powers, or the power supply unit and the energy storage unit use public power. When the power supply unit and the energy storage unit are public power sources, the energy storage unit serves as the primary power source and the power supply unit serves as the secondary power source. Alternatively, when energy is not stored in the energy storage unit, the power supply unit may be used as the power source.

When the secondary battery is manufactured, an activation process including a process of charging and discharging the secondary battery is performed. Conventionally, when discharging a secondary battery, discharge energy is consumed by using a resistance coil.

For example, when a 100 Ah battery cell is charged and discharged once, about 420 W is consumed as shown in Equation (1) below.

4.2 V x 100 Ah = 420 W ...Equation (1)

Typically, in the case of activating (formation) a battery cell, charging and discharging are performed three times, and in this case, 1.26 kW of power is consumed.

Furthermore, when the 42 V and 50 Ah modules are activated, about 6 kW of power is consumed, and in the case of a 1 GWh electric vehicle battery, about 3 GWh of power is consumed during the activation process.

In the present invention, by storing and utilizing the power lost during discharging the secondary battery in the energy storage device, it is possible to prevent power wastage. When power is stored in an energy storage device when the secondary battery is discharged, energy efficiency of about 95% is shown, and this can be used again when charging the secondary battery. Accordingly, the present invention can prevent a huge amount of power consumed in the secondary battery activation process and significantly increase energy efficiency.

In one embodiment, the power supply supplies AC power. In the present invention, it is located between the power supply unit and the terminal unit, includes a converter for converting AC power supplied from the power supply unit into DC power.

In another embodiment, in the charging mode, the controller primarily charges the secondary battery through the energy storage unit, and secondary charges the energy storage unit through the power supply unit. In the present invention, by setting the energy storage unit as the primary power source, the stored power is consumed first, and the shortage is covered by the external power source.

In one embodiment, the control unit charges a secondary battery by SOC a% through the energy storage unit and charges the secondary battery by SOC b% through the power supply in the charging mode, but the ratio of a to b (a/b) is in the range of 2 to 50, and the sum of a and b is in the range of 100 or less. For example, in the charging mode, the secondary battery may be fully charged by SOC by 85% through the energy storage unit and by SOC by 15% by charging the secondary battery by SOC through the power supply unit. For another example, in the charging mode, it is possible to charge the secondary battery by SOC of 65% through the energy storage unit and charge the secondary battery by SOC by 5% through the power supply, thereby charging the secondary battery by SOC of 70%.

As another example, in the charging mode, it is also possible to charge the secondary battery to SOC 70% by charging the secondary battery to SOC 70% through the energy storage unit. In this case, charging of the secondary battery through the power supply is not performed.

In one embodiment, in the discharging mode, the energy efficiency stored in the energy storage unit relative to the discharge amount of the secondary battery is 80% or more. When the secondary battery is discharged, since it can be stored in the energy storage unit without a separate conversion process, high energy efficiency can be realized. Specifically, the energy efficiency is greater than 85%, greater than 90%, or in the range of 83 to 98%. The energy efficiency may vary depending on the type of secondary battery to be charged and discharged. For example, in the case of a lithium secondary battery, energy efficiency of 90% or more, or 93 to 96% level may be realized. For another example, in the case of a lead-acid battery, energy efficiency of 80% or more, or 83 to 90% level can be implemented.

In one embodiment, the energy storage unit is an all-terrain energy storage system (BESS).

The present invention provides a method for charging and discharging a secondary battery using the above-described energy storage type charge/discharger. In one embodiment, a secondary battery charging/discharging method according to the present invention comprises the steps of charging a secondary battery to be charged and discharged; and discharging the charged secondary battery. Specifically, in the step of charging the secondary battery, the secondary battery is charged by using at least one of a power supply unit and an energy storage unit as a power source, and in the step of discharging the secondary battery, energy using the charged secondary battery as a power source Charge the storage unit.

The present invention is characterized in that the energy is stored in the energy storage unit when the secondary battery is discharged, and the stored energy is used when the secondary battery is charged. In one example, in the step of charging the secondary battery, the secondary battery is charged by SOC a% using the energy storage unit as a power source, and the secondary battery is charged by SOC b% by using the power supply unit as a power source, but the ratio of a to b (a/b) ranges from 2 to 50. For example, the secondary battery may be charged by SOC 95% by using the energy storage unit as the power source, and the secondary battery may be charged by SOC 5% by using the power supply unit as the power supply.

In another example, in the charging of the secondary battery, it is also possible to charge the secondary battery to a preset reference value using the energy storage unit as a power source. In this case, charging through the power supply is not separately performed.

In one specific example, in the charging of the secondary battery, the power supply unit supplies AC power, and the method further includes a conversion step of converting AC power supplied from the power supply unit into DC power through a converter. In addition, the energy storage unit supplies DC power and charges the secondary battery without a separate conversion step. Charging the secondary battery through the energy storage unit does not require a separate conversion step, so high energy efficiency can be achieved.

In one embodiment, the secondary battery charging/discharging method may be performed in any one or more processes of a secondary battery activation process and a secondary battery charging/discharging test.

In addition, the present invention provides another type of secondary battery charging/discharging method through the above-described energy storage type charging/discharging device. In one embodiment, the secondary battery charging/discharging method according to the present invention determines a charging or discharging mode for a secondary battery to be charged/discharged through a control unit.

Specifically, (a) in the charging mode, based on the preset charge amount SOC x% of the energy storage unit, when the charge amount of the energy storage unit is SOC x% or more, the secondary battery is charged using the energy storage unit as a power source, and the charge amount of the energy storage unit is When this SOC is less than x%, the secondary battery is charged using either the energy storage unit and the power supply unit as a power source or only the power supply unit as a power source, and x is in the range of 0 to 50 or 0.01 to 50. For example, (a) in the charging mode, based on the preset charge amount SOC of 30% of the energy storage unit, when the charge amount of the energy storage unit is SOC 30% or more, the secondary battery is charged using the energy storage unit as a power source, and the energy storage unit is charged. If the charge amount is less than 30% SOC, the secondary battery is charged by using the energy storage unit and the power supply unit together or using only the power supply unit as the power source.

In addition, (b) in the discharging mode, the energy discharged from the secondary battery is stored in the energy storage unit.

In another embodiment, in the discharging mode, the energy discharged from the secondary battery is stored in the energy storage unit, but the charge capacity of the energy storage unit is 90% or more of the discharge capacity of the secondary battery. For example, the charge capacity of the energy storage unit is twice the discharge capacity of the secondary battery. Through this, power discharged from the secondary battery can be effectively stored in the energy storage unit. Since the charging capacity of the energy storage unit may be variously applied, the discharge capacity of the secondary battery may vary depending on the type or shape of the battery.

In another embodiment, the charging capacity of the energy storage unit may be in the range of 10% to 90% of the discharge capacity of the secondary battery. In addition, it is possible to form a resistance coil connected in parallel with the energy storage unit, and through this, power not stored in the energy storage unit may be consumed through the resistance coil.

In a specific embodiment, the secondary battery charging/discharging method may be performed in any one or more of a secondary battery activation process and a secondary battery charge/discharge test.

The preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various modifications, changes, and additions are possible within the spirit and scope of the present invention by those skilled in the art having ordinary knowledge of the present invention. and additions shall be deemed to fall within the scope of the following claims.

Hereinafter, the present invention will be described in more detail with reference to drawings and the like, but the scope of the present invention is not limited thereto.

2 is a schematic diagram illustrating an energy storage type charger/discharger according to an embodiment of the present invention. Referring to FIG. 2 , the charger/discharger 100 according to the present invention includes a converter 120 for converting AC power supplied from the outside into DC power, and a controller 130 for controlling the operation or mode of the charger/discharger 100 . and an energy storage unit 150 for storing discharge energy of the secondary battery 300 . In addition, the charger/discharger 100 includes a power supply unit 110 electrically connected to an external power source 200 to receive AC power, and terminal units 141 and 142 in electrical contact with the secondary battery 300 . include

The secondary battery 300 is a secondary battery, and may be in the form of a battery cell, or may be in the form of a battery module or battery pack. For example, the secondary battery 300 is a battery pack in which pouch-type battery cells are assembled. The secondary battery 300 includes secondary battery terminal parts 311 and 312 that are electrically connected to or in contact with the outside.

The control unit 130 controls the operation or mode of the charger/discharger 100 . Specifically, the charging mode or the driving mode for the secondary battery 300 is controlled and switched.

The energy storage unit 150 stores the discharge energy of the secondary battery 300 . The electric energy stored in the energy storage unit 150 may be utilized when charging the secondary battery 300 . The energy storage unit 150 is in the form of an Energy Storage System (ESS) or a Battery Energy Storage System (BESS).

3 and 4 are schematic diagrams showing a charging mode or a discharging mode of the charger/discharger according to an embodiment of the present invention, respectively.

First, referring to FIG. 3 , a charging mode of the charger/discharger is shown. In the charging mode, the secondary battery 300 is charged by using at least one of the power supply unit 110 and the energy storage unit 150 as a power source. In this case, the controller 130 controls the energy storage unit 150 as the primary power source and the power supply unit 110 as the secondary power source.

For example, by charging the secondary battery 300 by SOC 95% through the energy storage unit 150 and charging the secondary battery 300 by SOC 5% through the power supply unit 120, the secondary battery 300 is It is possible to buffer for

Referring to FIG. 4 , a discharge mode of the charger/discharger is shown. In the discharge mode, the discharge energy of the secondary battery 300 is stored in the energy storage unit 150, and the efficiency is about 95%. Energy stored in the energy storage unit 150 is used to charge the secondary battery 300 .

In addition, energy efficiency according to the type of the secondary battery 300 to be charged and discharged is shown in Table 1 below. In Table 1, the energy storage unit 150 is calculated based on the case of a lithium secondary battery.

Secondary battery capacity Energy efficiency (%) by type of secondary battery lithium secondary battery lead acid battery More than 100 kW ~ 250 kW or less 95 85 More than 250 kW to less than 500 kW More than 500 kW to less than 1000 kW 94 More than 1000 kW ~ 2500 kW or less

Referring to Table 1, it was confirmed that the lithium secondary battery showed an energy efficiency of 94% or 95%, the lead-acid battery showed an energy efficiency of 85%, and the redox flow battery showed an energy efficiency of about 70%.

In another embodiment, although not shown in FIG. 4 , a structure in which a coil resistor is connected in parallel with the energy storage unit 150 is also possible. Through this, the discharge energy exceeding the capacity of the energy storage unit 150 can be consumed through the coil resistance.

Although the present invention has been described with reference to the above drawings, this is for technical description, and the scope of the present invention is not limited thereto.

[Explanation of code]

10, 100: Charger/discharger

11, 110: external power supply line

12, 120: conversion unit

13, 130: control unit

14(a), 14(b), 141, 142: charger/discharger terminal unit

15: coil resistance

150: energy storage unit

20, 200: power supply

30, 300: secondary battery

31, 32, 310, 320: secondary battery terminal part

Claims (13)

a power supply for supplying electrical energy from the outside; a terminal part electrically connected to the power supply part and in electrical contact with a secondary battery to be charged/discharged; an energy storage unit electrically connected to the terminal unit and storing electrical energy; and a control unit electrically connected to the power supply unit, the terminal unit and the energy storage unit, respectively, to control the charging and discharging modes thereof; (i) in the charging mode, the secondary battery is charged by using any one or more of the power supply unit and the energy storage unit as a power source, (ii) in the discharging mode, an energy storage type charger/discharger, characterized in that the energy storage unit is charged by using the charged secondary battery as a power source. The method of claim 1, The power supply supplies AC power, Located between the power supply unit and the terminal unit, the energy storage type charger/discharger further comprising a converter for converting AC power supplied from the power supply unit to DC power. The method of claim 1, The controller is an energy storage type charger/discharger, characterized in that in the charging mode, the secondary battery is primarily charged through the energy storage unit, and the energy storage unit is secondaryly charged through the power supply unit. The method of claim 1, In the charging mode, the control unit charges the secondary battery by SOC a% through the energy storage unit, and charges the secondary battery by SOC b% through the power supply, but the ratio of a to b (a/b) is in the range of 2 to 50, and The sum of a and b is in the range of 100 or less. The method of claim 1, In the discharging mode, the energy stored in the energy storage unit compared to the discharge amount of the secondary battery is 80% or more energy storage type charge/discharger. The method of claim 1, The energy storage unit is an energy storage type energy storage device (BESS), characterized in that the charge/discharger. charging a secondary battery to be charged/discharged; and Including any one or more of the steps of discharging the charged secondary battery, In the charging of the secondary battery, the secondary battery is charged by using at least one of a power supply unit and an energy storage unit as a power source, In the step of discharging the secondary battery, a secondary battery charging/discharging method for charging the energy storage unit using the charged secondary battery as a power source. 8. The method of claim 7, In the step of charging the secondary battery, The secondary battery is charged by SOC a% using the energy storage unit as the power source, and the secondary battery is charged by SOC b% using the power supply unit as the power supply, but the secondary battery charging with a ratio of a to b (a/b) in the range of 2 to 50 discharge method. 8. The method of claim 7, In the step of charging the secondary battery, The power supply supplies AC power, Through the converter, further comprising a conversion step of converting the AC power supplied from the power supply to DC power, The energy storage unit supplies DC power and charges the secondary battery without a separate conversion step. 8. The method of claim 7, The secondary battery charging/discharging method is a secondary battery charging/discharging method, characterized in that it is performed in any one or more of a secondary battery activation process and a charging/discharging test for the secondary battery. In the method for charging and discharging a secondary battery through the energy storage type charge/discharger according to claim 1, Determine the charging or discharging mode for the secondary battery to be charged and discharged through the control unit, (a) In the charging mode, based on the preset charge amount SOC x% of the energy storage unit, if the charge amount of the energy storage unit is SOC x% or more, the secondary battery is charged using the energy storage unit as a power source, and the charge amount of the energy storage unit is SOC x %, the secondary battery is charged by using the energy storage unit and the power supply unit together or only the power supply unit as a power source, and x is in the range of 0 to 50, (b) a secondary battery charging/discharging method in which, in the discharging mode, energy discharged from the secondary battery is stored in the energy storage unit. 12. The method of claim 11, In the discharge mode, the energy discharged from the secondary battery is stored in the energy storage unit, The charging capacity of the energy storage unit is a secondary battery charging and discharging method, characterized in that 90% or more of the secondary battery discharge capacity. 12. The method of claim 11, The secondary battery charging/discharging method is a secondary battery charging/discharging method, characterized in that it is performed in any one or more of a secondary battery activation process and a charging/discharging test for the secondary battery.

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