Charging Control System and Method between Battery Packs

Abstract

The present invention relates to a system and method for controlling charging between battery packs in series, and relates to a system and method for controlling charging between battery packs in series that is configured so that, when the battery packs are connected to and stored in a system and there is a large voltage difference between the two battery packs, the higher-voltage battery pack can charge the lower-voltage battery pack to reduce the voltage difference between the battery packs.

Description

[Technical field]

[0001] The present invention relates to a system and method for controlling charging between battery packs, and more particularly to a system and method for controlling charging between battery packs in series, capable of reducing a difference in state of charge (SOC) between battery packs in series connected to an external system. [Background technology]

[0002] Batteries are used in a wide range of fields, including not only portable electronic devices such as smartphones, laptops, and tablet PCs, but also electric scooters, electric cars, energy storage devices, etc. In fields such as electrically powered vehicles or smart grid systems, large capacity is often required, so multiple battery packs are connected in series to increase output.

[0003] Normally, light electric vehicles (LEVs) such as electric bicycles and electric scooters use two battery packs in series. In this case, if the SOC of the two battery packs is not the same, discharging will end when the SOC of the battery pack with the lower SOC reaches 0% while driving, and the driving will end at that point.

[0004] Therefore, since the driving range is calculated and the system is controlled based on the battery pack with the lower SOC, when two battery packs with a large SOC difference are used, the system is controlled based on the battery pack with the lower SOC, which causes an unexpectedly short driving range, causing inconvenience and anxiety to the user.

[0005] In this regard, Japanese Patent Publication No. 2013-240219 discloses a technical idea of ​​performing parallel stabilization before the batteries are used to equalize the capacity of two battery blocks connected in series, but does not disclose any technology for switching between series / parallel depending on the battery usage status.

[0006] The following documents are cited as examples of conventional techniques. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-240219 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been devised to solve the above-mentioned problems, and has an object to provide a system and method for controlling charging between battery packs, which is configured such that when the battery packs are connected to a system and there is a large difference in state of charge (SOC) between the two battery packs in a standby state, the battery pack with a higher SOC can charge the battery pack with a lower SOC, thereby reducing the SOC difference between the battery packs. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention provides a charging control system between series battery packs, comprising a first battery pack, a second battery pack, and a battery connection unit, wherein the battery connection unit connects the first and second battery packs in parallel and cuts off output to the external system when an external system is in a standby state, and connects the first and second battery packs in series and outputs the series connection output to the external system when the external system is in an active state.

[0010] In this case, the battery connection unit may include an input unit that receives the outputs of the first and second battery packs, an output unit that outputs or cuts off the outputs of the first and second battery packs input to the input unit to an external system, and a path connection unit that forms a connection between the first and second battery packs between the input unit and the output unit.

[0011] The input unit includes a first (+) connection part connected to the (+) terminal of the first battery pack, a second (+) connection part connected to the (+) terminal of the second battery pack, a first (-) connection part connected to the (-) terminal of the first battery pack, and a second (-) connection part connected to the (-) terminal of the second battery pack, and the path connection part includes a first (-) connection part and a second (-) connection part connected to the (-) terminal of the second battery pack. the first (+) connection portion and the second (+) connection portion; a third path connecting the second (+) connection portion and the (+) output terminal; a fourth path connecting the first (+) connection portion and the second (-) connection portion; a fifth path connecting the first (-) connection portion and the (-) output terminal; and first to fifth switches opening and closing the first to fifth paths, respectively.

[0012] In this case, the external system periodically acquires SOC values ​​from the first and second battery packs, calculates and compares a pack SOC difference using the SOC values, and when the pack SOC difference exceeds a predetermined reference pack SOC difference, outputs a parallel switching signal to connect the first and second battery packs in parallel, thereby making it possible to match the SOC of the two battery packs. When the pack SOC difference falls within a predetermined reference pack SOC difference, the parallel connection of the first and second battery packs is switched to a series connection. Effect of the Invention

[0013] According to an embodiment of the present invention, when the difference in state of charge (SOC) between two battery packs exceeds a reference difference while the batteries are connected to the system and stored, the battery pack with a higher SOC can charge the battery pack with a lower SOC to reduce the SOC difference between the two battery packs, thereby increasing the actual driving distance of the system and improving user convenience. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing an overall configuration of a system according to an embodiment of the present invention. [Diagram 2] 4 is a diagram illustrating an operation in which a high-voltage battery pack charges a low-voltage battery pack according to an embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram showing a detailed configuration of a control unit according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating a method for controlling charging between series battery packs according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that a person having ordinary skill in the art to which the present invention pertains can easily carry out the present invention. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, in order to clearly explain the present invention, parts that are not related to the description are omitted, and similar parts are denoted by similar reference numerals throughout the specification.

[0016] The present invention will now be described in detail with reference to the accompanying drawings.

[0017] 1. CHARGE CONTROL SYSTEM BETWEEN SERIES BATTERY PACKS ACCORDING TO THE PRESENT PRESENT EMBODIMENT

[0018] FIG. 1 is a diagram illustrating an overall configuration of a system for controlling charging between series-connected battery packs according to an embodiment of the present invention.

[0019] Referring to FIG. 1, a system according to an embodiment of the present invention includes the following components:

[0020] 1.1.2 or higher battery pack

[0021] The system of the present invention comprises two or more battery packs 100, 200 connected in series with each other.

[0022] 1.1.1. First Battery Pack 100

[0023] As shown in FIG. 1, the first battery pack 100 includes a first battery cell module 110 and a first discharge circuit unit 120.

[0024] A. First battery cell module 110

[0025] The first battery cell module 110 includes one or more battery cells (not shown), a first cell module (+) terminal and a first battery cell module (-) terminal.

[0026] A. First discharge circuit unit 120

[0027] The first discharge circuit unit 120 (121, 122, 123, 124) refers to a current path configured between the first battery cell module 110 and a battery connection unit 400 described later. More specifically, it is formed in a path connecting the first cell module (+) terminal of the first battery cell module 110 and the first battery pack (+) terminal.

[0028] 1) First discharge field effect transistor (FET) (D-FET) 121

[0029] The first discharge FET (D-FET) 121 is disposed in series between the first cell module (+) terminal and the first discharge resistor 122 .

[0030] The first discharge FET (D-FET) 121 is turned on by a switching control unit 318 of the control unit 310 described later when the external system 300 connected to the first and second battery packs 100, 200, in which the SOC of the second battery pack 200 is higher than that of the first battery pack 100, is in a standby state, i.e., when the user is not using the external system 300.

[0031] 2) First discharge resistor 122

[0032] The first discharge resistor 122 is arranged in series between the first discharge FET (D-FET) 121 and the first discharge pre-charge FET (pre-FET) 123. The first discharge resistor 122 arranged in this manner functions to limit the amount of charging current flowing from the first battery pack 100 to the second battery pack 200 when the voltage of the first battery pack 100 is higher than the voltage of the second battery pack 200.

[0033] 3) First discharge pre-charge FET (P-FET) 123

[0034] A first discharging pre-charge FET (P-FET) 123 is arranged in series with the first discharging resistor 122 and the first cell module (+) terminal.

[0035] 4) First charge FET (C-FET) 124

[0036] The first discharge D-FET 124 is arranged in series between the output of the first discharge FET (D-FET) 121 and the first cell module (+) terminal, and is arranged in parallel with the series connection of the first discharge resistor 122 and the first discharge pre-charge FET (P-FET) 123.

[0037] 1.1.2. Second Battery Pack 200

[0038] As shown in FIG. 1, the second battery pack 200 includes a second battery cell module 210 and a second discharge circuit unit 220.

[0039] A. Second battery cell module 210

[0040] The second battery cell module 210 includes one or more battery cells (not shown) and a second cell module (+) terminal and a second battery cell module (-) terminal.

[0041] A. Second discharge circuit section 220

[0042] The second discharge circuit unit 220 (221, 222, 223, 224) refers to a current path configured between the second battery cell module 210 and a battery connection unit 400 described later. More specifically, it is formed in a path connecting the second cell module (+) terminal of the second battery cell module 210 and the second battery pack (+) terminal.

[0043] 1) Second Discharge FET (D-FET) 221

[0044] The second discharge FET (D-FET) 221 is disposed in series between the (+) terminal of the first cell module and the second discharge resistor 222 .

[0045] The second discharge FET (D-FET) 221 is turned on by a switching control unit 318 of the control unit 310 described later when the external system 300 connected to the first and second battery packs 100, 200, in which the SOC of the first battery pack 100 is higher than that of the second battery pack 200, is in a standby state, i.e., when the user is not using the external system 300.

[0046] 2) Second discharge resistor 222

[0047] The second discharge resistor 222 is arranged in series between the second discharge FET (D-FET) 221 and the second discharge pre-charge FET (p-FET) 223. The second discharge resistor 222 arranged in this manner functions to limit the amount of charging current flowing from the second battery pack 200 to the first battery pack 100 when the voltage of the second battery pack 200 is higher than the voltage of the first battery pack 200.

[0048] 3) A second discharge pre-charge FET (P-FET) 223

[0049] A second discharge P-FET 223 is disposed in series with the second discharge resistor 222 and the second cell module (+) terminal.

[0050] 4) Second Charge FET (C-FET) 224

[0051] The second charge FET (C-FET) 224 is arranged in series between the output of the second discharge FET 221 and the second cell module (+) terminal, and is arranged in parallel with the series connection of the second discharge resistor 222 and the second discharge P-FET 223.

[0052] FIG. 3 is a diagram showing a detailed configuration of a control unit according to an embodiment of the present invention.

[0053] Control Unit 310

[0054] The control unit 310 is a component that performs charging control between the first and second battery packs 100, 200 based on the SOC difference between the first and second battery packs 100, 200 in a standby state of the external system 300 connected to the first and second battery packs 100, 200.

[0055] A.Pac SOC Acquisition Department 312

[0056] The pack SOC acquisition unit 312 is a component that periodically acquires the SOC value from each of the first and second battery packs 100, 200. A known SOC calculation method is used to acquire or calculate the SOC.

[0057] A. System state recognition unit 314

[0058] The system state recognition unit 314 is a component that recognizes whether the external system 300 is in a standby state or an active state while connected to the first and second battery packs 100 and 200.

[0059] Here, the standby state refers to a state in which the first and second battery packs 100, 200 and the external system 300 are connected to each other and the user does not use the external system 300.

[0060] Meanwhile, the active state refers to a state in which the first and second battery packs 100 and 200 are connected to the external system 300 and a user is using the external system 300.

[0061] When a wait state is recognized, for example, a wait state signal can be output.

[0062] When it is recognized that it is in an active state, for example, an active state signal can be output.

[0063] C. Connection switching determination unit 316

[0064] The connection switching determination unit 316 is a component that determines whether or not the connection state between the first and second battery packs 100, 200 is switched based on the SOC difference between the first and second battery packs 100, 200 when a wait state signal is output from the system state recognition unit 314.

[0065] Such a connection switching determination unit 316 may include the following detailed components.

[0066] 1) Pack SOC difference calculation unit 3162

[0067] The pack SOC difference calculation unit 3162 calculates a pack SOC difference, which is the value of the SOC difference between the first and second battery packs 100, 200, using the SOC values ​​of each of the first and second battery packs 100, 200 acquired by the pack SOC acquisition unit 312.

[0068] 2) Comparison judgment section 3164

[0069] The comparison and determination unit 3164 compares whether the calculated pack SOC difference exceeds a predetermined reference pack SOC difference, and when the calculated pack SOC difference exceeds the predetermined reference pack SOC difference, determines to switch the connection state of the first and second battery packs 100, 200 to a parallel connection. When it is determined to switch the connection state of the first and second battery packs 100, 200 to a parallel connection, a signal indicating this, for example, a parallel switching signal, may be output.

[0070] Furthermore, after the parallel switching signal is output, if the pack SOC difference calculated by the pack SOC difference calculation unit 3162 falls within a predetermined reference SOC difference, it is determined that the connection state of the first and second battery packs 100, 200 is switched to series connection. In this case, a signal indicating this, for example, a series switching signal, may be output.

[0071] D. Switching control unit 318

[0072] The switching control section 318 is a component that controls opening and closing of first to fifth switches SW1 to SW5 that are configured in the battery connection section 400, which will be described later.

[0073] Specifically, when a parallel switching signal is output from the connection switching determination unit 316, the third, fourth, and fifth switches SW3, SW4, SW5 are turned off to open the third, fourth, and fifth paths L3, L4, L5, and the first and second switches SW1, SW2 are turned on to close the first and second paths L1, L2, thereby connecting the first and second battery packs 100, 200 in parallel with each other.

[0074] This allows the output to the external system 300 to be cut off, and the battery pack with the higher SOC of the first and second battery packs 100, 200 to charge the battery pack with the lower SOC.

[0075] On the other hand, when a series switching signal is output from the connection switching determination unit 316, or when an activation signal is output from the system state recognition unit 314, the third, fourth, and fifth switches SW3, SW4, SW5 are turned on to close the third, fourth, and fifth paths L3, L4, L5, and the first and second switches SW1, SW2 are turned off to open the first and second paths L1, L2, thereby connecting the first and second battery packs 100, 200 in series with each other. As a result, the series connection output of the first and second battery packs 100, 200 is supplied to the external system 300.

[0076] FIG. 2 is a diagram illustrating an operation in which a battery pack with a high SOC charges a battery pack with a low SOC according to an embodiment of the present invention.

[0077] Referring to FIG. 2, for example, when the SOC difference between the first and second battery packs 100, 200 exceeds a predetermined reference SOC difference and the SOC of the second battery pack 200 is higher than the SOC of the first battery pack 100, the third, fourth, and fifth switches SW3, SW4, SW5 are turned off to open the third, fourth, and fifth paths L3, L4, L5, and the first and second switches SW1, SW2 are turned on to close the first and second paths L1, L2, thereby connecting the first and second battery packs 100, 200 in parallel with each other.

[0078] In addition, the second charge FET (C-FET) 224 is turned off, the second discharge FET (D-FET) 221 and the second discharge P-FET 223 are turned on, and the first charge FET 124 is turned on so that the current of the second battery cell module 210 flows to the first battery cell module 110 to charge it, thereby eliminating the SOC difference between the battery packs 100, 200.

[0079] Conversely, when the SOC of the second battery pack 200 is lower than the SOC of the first battery pack 100, the first and second battery packs can be connected in parallel in the same manner as described above, the first discharge FET 121 and the first discharge P-FET 123 of the first battery pack can be turned on, and the second charge FET 224 of the second battery pack can be turned on so that the current of the first battery cell module 110 flows to the second battery cell module 210 for charging, thereby eliminating the SOC difference between the battery packs 100, 200.

[0080] Such a control unit 310 can be implemented within the external system 300 and can transmit control signals to a battery management system (BMS) (not shown) of the first and second battery packs to control the opening and closing of the transistors 121, 123, 124, 221, 223, and 224.

[0081] Here, the external system 300 refers to a light electric vehicle (LEV), which includes, for example, an electric bicycle, an electric scooter, and the like.

[0082] 1.3. Battery Connection 400

[0083] When the external system 300 connected to the first and second battery packs 100, 200 is in a standby state, the battery connection unit 400 connects the first and second battery packs 100, 200 in parallel and cuts off the output of the external system 300 based on a control signal from the control unit 310.

[0084] On the other hand, when the external system 300 connected to the first and second battery packs 100, 200 is in an active state, the first and second battery packs 100, 200 are connected in series based on a control signal from the control unit 310, and the series connection output is output to the external system 300.

[0085] Such a battery connector 400, as shown in FIG. 1, includes the following detailed components:

[0086] A. Input unit 410

[0087] The input unit is a component that receives the outputs of the first and second battery packs 100, 200.

[0088] 1) First (+) connection 412

[0089] The first (+) connection is connected to the (+) terminal of the first battery pack 100.

[0090] 2) Second (+) connection 414

[0091] The second (+) connection is connected to the (+) terminal of the second battery pack 200.

[0092] 3) First (-) connection part 416

[0093] The first (-) connection is connected to the (-) terminal of the first battery pack 100.

[0094] 4) Second (-) connection part 418

[0095] The second (-) connection is connected to the (-) terminal of the second battery pack 200.

[0096] A. Output unit 420

[0097] The output unit is a component that outputs or cuts off the output of the first and second battery packs 100 and 200 input to the input unit to the external system 300.

[0098] 1) (+) output terminal 422

[0099] The (+) output terminal connects the (+) outputs of the first and second battery packs 100 , 200 in series to the external system 300 .

[0100] 2) (-) Output terminal 424

[0101] The (-) output terminal connects the (-) outputs of the first and second battery packs 100 and 200 in series to the external system 300.

[0102] C. Route connection section 400

[0103] The path connection unit 400 constitutes a connection between the first and second battery packs 100, 200 between the input and output units, and includes the following detailed components.

[0104] 1) First route L1

[0105] The first path L1 is a path that connects the first (-) connecting portion 416 and the second (-) connecting portion 418, and is opened and closed by the first switch SW1.

[0106] 2) Second route L2

[0107] The second path L2 is a path that connects the first (+) connecting portion 412 and the second (+) connecting portion 414, and is opened and closed by the second switch SW2.

[0108] 3) The third pathway, L3

[0109] The third path L3 is a path that connects the second (+) connection portion 414 and the (+) output terminal 422, and is opened and closed by the third switch SW3.

[0110] 4) The fourth pathway L4

[0111] The fourth path L4 is a path that connects the first (+) connecting portion 412 and the second (-) connecting portion 418, and is opened and closed by a fourth switch SW4.

[0112] 5) Fifth Route L5

[0113] The fifth path L5 is a path that connects the first (-) connection portion 416 and the (-) output terminal 424, and is opened and closed by a fifth switch SW5.

[0114] 6) First switch SW1

[0115] A first switch SW1 is disposed on the first path L1 and is turned on / off under the control of a switching control unit 318 of the control unit 310 to open / close the first path L1.

[0116] 7) Second switch SW2

[0117] A second switch SW2 is arranged on the second path L2 and is turned on / off under the control of a switching control unit 318 of the control unit 310 to open / close the second path L2.

[0118] 8) Third switch SW3

[0119] A third switch SW3 is disposed on the third path L3 and is turned on / off under the control of a switching control unit 318 of the control unit 310 to open / close the third path L3.

[0120] 9) Fourth switch SW4

[0121] A fourth switch SW4 is disposed on the fourth path L4 and is turned on / off under the control of the switching control unit 318 of the control unit 310 to open / close the fourth path L4.

[0122] 10) Fifth switch SW5

[0123] A fifth switch SW5 is arranged on the fifth path L5 and is turned on / off under the control of the switching control unit 318 of the control unit 310 to open / close the fifth path L5.

[0124] 2. Method for controlling charging between series battery packs according to the present invention

[0125] FIG. 4 is a diagram illustrating a method for controlling charging between series-connected battery packs according to an embodiment of the present invention.

[0126] 4, in a method according to an embodiment of the present invention, when two or more battery packs connected in series to each other are connected and / or mounted on an external system (e.g., an electric bicycle, an electric scooter, etc.), the SOC difference between the battery packs is eliminated by switching between series / parallel connections depending on the state of the SOC difference between the battery packs and whether or not the external system is in a standby state. The method includes the following steps.

[0127] 2.1. Pack SOC Acquisition Step (S100)

[0128] The pack SOC acquisition step (S100) is a step in which control unit 310 acquires the SOC value of each of series battery packs 100, 200 at regular intervals.

[0129] More specifically, in the configuration of a control unit 310 implemented in an external system 300 connected to series battery packs 100, 200, by establishing a communication connection with the battery packs 100, 200, the SOC values ​​of each can be obtained at regular intervals.

[0130] 2.2. System Waiting State Recognition Step (S200)

[0131] The system standby state recognition step (S200) is a step for recognizing whether or not external system 300 is in a standby state while connected to series battery packs 100, 200.

[0132] Specifically, when the series battery packs 100, 200 and the external system 300 are connected, the components of the control unit 310 implemented in the external system 300 can recognize whether the external system 300 is in a standby state.

[0133] Here, the standby state refers to a state in which the first and second battery packs 100, 200 and the external system 300 are connected to each other and the external system 300 does not use the serial outputs of the battery packs 100, 200.

[0134] On the other hand, when it is not in the standby state, it refers to a state in which the first and second battery packs 100, 200 are connected to the external system 300 and the external system 300 is driven by the serial output of the battery packs 100, 200.

[0135] 2.3. Step of switching to parallel connection (S300)

[0136] The step of switching to parallel connection (S300) is a step of switching the connection state between the first and second battery packs 100, 200 based on the SOC difference between the first and second battery packs 100, 200 when it is recognized in the system standby state recognition step (S200) that the external system 300 is in a standby state.

[0137] A. First pack SOC difference calculation step

[0138] The first pack SOC difference calculation step is a step of calculating the SOC difference between the first and second battery packs 100, 200 using the respective SOC values ​​of the battery packs 100, 200 acquired in the pack SOC acquisition step (S100) when the external system 300 is recognized to be in a standby state in the system standby state recognition step (S200).

[0139] A. First comparison and judgment step

[0140] The first comparison and judgment step is a step of comparing whether the SOC difference between the first and second battery packs 100, 200 calculated in the first pack SOC difference calculation step exceeds a predetermined reference pack SOC difference, and determining whether to switch the series connection of the battery packs 100, 200 to a parallel connection based on the comparison result.

[0141] More specifically, if the comparison result indicates that the SOC difference between the first and second battery packs 100, 200 exceeds a predetermined reference pack SOC difference, it is determined that the series connection of the battery packs 100, 200 should be switched to a parallel connection, and the parallel connection is switched.

[0142] That is, if a decision is made in the first comparison and decision step to switch to parallel connection, switching to parallel connection is performed.

[0143] Referring to FIG. 1, this can be achieved by turning off the third, fourth, and fifth switches SW3, SW4, SW5 of the battery connection unit 400 configured between the first and second battery packs 100, 200 and the external system 300 to open the third, fourth, and fifth paths L3, L4, L5, and turning on the first and second switches SW1, SW2 to close the first and second paths L1, L2, thereby connecting them in parallel with each other.

[0144] Using these steps, the first and second battery packs 100, 200 are connected in parallel, and as shown in FIG. 2, a current flows from the battery pack with a higher SOC to the battery pack with a lower SOC among the first and second battery packs 100, 200, thereby performing charging, thereby eliminating the SOC difference between the battery packs.

[0145] 2.4. Connection switching determination step (S400)

[0146] The connection switching determination step (S400) is a step of determining whether or not to switch the parallel connection of the first and second battery packs 100, 200 to a series connection depending on whether or not the SOC difference between the first and second battery packs 100, 200 is within a predetermined reference pack SOC difference after switching to the parallel connection in the parallel connection switching step (S300).

[0147] A. Second pack SOC difference calculation step

[0148] The second pack SOC difference calculation step is a step of calculating the SOC difference between the battery packs 100, 200 using the respective SOC values ​​of the first and second battery packs 100, 200 acquired in the pack SOC acquisition step (S100) after the first and second battery packs 100, 200 are connected in parallel in the parallel connection switching step (S300).

[0149] A. The second comparative judgment step

[0150] The second comparison judgment step is a step of comparing whether the SOC difference between the first and second battery packs 100, 200 calculated in the second pack SOC difference calculation step is within a predetermined reference pack SOC difference, and if it is within the predetermined reference pack SOC difference, determining to switch the parallel connection of the first and second battery packs 100, 200 to a series connection.

[0151] 2.5. Step of switching to series connection (S500)

[0152] The step of switching to a series connection (SS00) is a step of switching the first and second battery packs 100, 200 to a series connection when it is determined in the step of determining whether or not to switch the parallel connection of the first and second battery packs 100, 200 to a series connection (S400).

[0153] Referring to FIG. 1, this can be achieved by turning on the third, fourth, and fifth switches SW3, SW4, SW5 of the battery connection unit 400 configured between the first and second battery packs 100, 200 and the external system 300 to close the third, fourth, and fifth paths L3, L4, L5, and turning off the first and second switches SW1, SW2 to open the first and second paths L1, L2, thereby connecting the first and second battery packs 100, 200 in series with each other.

[0154] In this manner, when the series battery packs 100, 200 are stored in connection with the external system 300, if there is a large difference in SOC between the battery packs, the battery packs can be connected in parallel to each other by controlling a switch configured between the battery packs and the external system 300, and the battery pack with a higher SOC can charge the battery pack with a lower SOC, thereby eliminating the difference in SOC between the battery packs. Therefore, the time during which the first and second battery packs 100, 200 can be output in series can be maximized, thereby improving the usability and efficiency of the external system 300.

[0155] Meanwhile, although the technical idea of ​​the present invention has been specifically described based on the above embodiment, it should be noted that the above embodiment is for the purpose of explanation and not for the purpose of limiting the present invention. It should be understood by those skilled in the art that various embodiments are possible within the scope of the technical idea of ​​the present invention.

[0156] The names of the reference numerals in the drawings used in the present invention are as follows: [Explanation of symbols]

[0157] 100, 200 First and second battery packs 120, 220 First and second discharge circuit sections 121, 221 First and second discharge FETs 122, 222 First and second discharge resistors 123, 223 First and second discharge P-FETs 124, 224 First and second charge FETs 300 External Systems 310 Control section 312 Pack SOC Acquisition Department 314 System Status Recognition Unit 316 Connection switching presence / absence determination unit 3162 Pack SOC Difference Calculation Unit 3164 Comparison Judgment Department 318 Switching control section 400 Battery connection

Claims

1. A battery pack charging control system including a first battery pack, a second battery pack, and a battery connection unit, The battery connection portion is When the external system is in a standby state, the first and second battery packs are connected in parallel and an output to the external system is cut off; a charging control system between battery packs, which connects the first and second battery packs in series and outputs an output of the series connection to the external system when the external system is in an active state;

2. The battery connection portion is an input unit to which outputs of the first and second battery packs are input; an output unit that outputs or cuts off the outputs of the first and second battery packs input to the input unit to an external system; a path connection portion that configures a connection between the first and second battery packs between the input portion and the output portion; The charging control system between battery packs according to claim 1 , comprising:

3. The input unit is a first (+) connection portion connected to a (+) terminal of the first battery pack; a second (+) connection portion connected to a (+) terminal of the second battery pack; a first (-) connection portion connected to a (-) terminal of the first battery pack; a second (-) connection portion connected to a (-) terminal of the second battery pack; Equipped with The path connection unit is a first path connecting the first (-) connection part and the second (-) connection part; a second path connecting the first (+) connection portion and the second (+) connection portion; a third path connecting the second (+) connection portion and the (+) output end; a fourth path connecting the first (+) connection portion and the second (-) connection portion; a fifth path connecting the first (−) connection portion and the (−) output end; first to fifth switches for opening and closing the first to fifth paths, respectively; The charging control system between battery packs according to claim 2 , comprising:

4. The first and second battery packs include a first discharge circuit unit and a second discharge circuit unit are provided in paths connecting the (+) end of the cell module and the (+) terminal of the pack, The first and second discharge circuit units include a discharge FET (field effect transistor), a discharge resistor and a discharge pre-charge FET connected in series to the discharge FET; a charge FET connected in parallel with the series connected resistor and discharge pre-charge FET; The charging control system between battery packs according to claim 3 , comprising:

5. The external system includes a control unit. The control unit is a pack SOC acquisition unit that acquires an SOC (remaining capacity) value from each of the first and second battery packs at regular intervals; a system state recognition unit that recognizes whether the external system is in a wait state and outputs a wait state signal when the external system is in a wait state; a connection switching determination unit that determines whether a connection state between the first and second battery packs is switched based on an SOC difference between the first and second battery packs when a standby state signal is output from the system state recognition unit; a switching control unit that controls opening and closing of the first to fifth switches; The charging control system between battery packs according to claim 4 , comprising:

6. The connection switching determination unit is a pack SOC difference calculation unit that calculates a pack SOC difference by using the SOC values ​​of the first and second battery packs acquired by the pack SOC acquisition unit when the wait state signal is output; a comparison and determination unit that compares whether the calculated pack SOC difference exceeds a predetermined reference pack SOC difference, and determines to switch the first and second battery packs to a parallel connection when the calculated pack SOC difference exceeds the predetermined reference pack SOC difference; Equipped with 6. The charging control system for battery packs according to claim 5, further comprising a parallel switching signal outputted when the comparison and judgment unit judges that the parallel connection should be switched to.

7. The switching control unit is 7. The charging control system according to claim 6, wherein, when the parallel switching signal is output, the third, fourth, and fifth switches are turned off to open the third, fourth, and fifth paths, and the first and second switches are turned on to close the first and second paths, thereby connecting the first and second battery packs in parallel.

8. The comparison and determination unit is After the parallel switching signal is output, if the pack SOC difference calculated by the pack SOC difference calculation unit becomes within a predetermined reference pack SOC difference, it is determined that the first and second battery packs are to be switched to a series connection, and a series switching signal is output; The switching control unit is 8. The charging control system according to claim 7, wherein, when the series switching signal is output, the third, fourth, and fifth switches are turned on to close the third, fourth, and fifth paths, and the first and second switches are turned off to open the first and second paths, thereby connecting the first and second battery packs in series.

9. In a method for controlling charging between battery packs, a pack SOC acquisition step of acquiring SOC values ​​of the first and second battery packs at regular intervals in the external system; a system wait state recognition step of recognizing whether the external system is in a wait state; When it is recognized that the external system is in a standby state, switching to a parallel connection in which the first and second battery packs are connected in parallel based on an SOC difference between the first and second battery packs; Including, The step of switching to the parallel connection includes: a first pack SOC difference calculation step of calculating a pack SOC difference by using the SOC values ​​of the first and second battery packs acquired in the pack SOC acquisition step when it is recognized that the external system is in a standby state; a first comparison and determination step of comparing whether the calculated pack SOC difference exceeds a predetermined reference pack SOC difference, and determining to switch the first and second battery packs to a parallel connection if the calculated pack SOC difference exceeds the predetermined reference pack SOC difference; A method for controlling charging between battery packs, comprising:

10. The step of switching to the parallel connection includes:

10. The method for controlling charging between battery packs according to claim 9, further comprising turning off third, fourth, and fifth switches of a battery connection section configured between the first and second battery packs and an external system to open the third, fourth, and fifth paths, and turning on the first and second switches to close the first and second paths, thereby connecting the first and second battery packs in parallel.

11. a connection switching determination step of determining whether or not to switch the parallel connection of the first and second battery packs to a series connection depending on whether or not an SOC difference between the first and second battery packs is within a predetermined reference pack SOC difference after the switching to parallel connection step; a step of switching to a series connection in which the first and second battery packs are connected in series when it is determined in the step of determining whether or not to switch the connection to a series connection, Further comprising: The connection switching determination step includes: a second pack SOC difference calculation step of calculating a pack SOC difference by using the SOC values ​​of the first and second battery packs acquired in the pack SOC acquisition step after the parallel connection; a second comparison and determination step of determining to switch the parallel connection of the first and second battery packs to a series connection when the calculated pack SOC difference is within a predetermined reference SOC difference; The method for controlling charging between battery packs according to claim 9 , comprising:

12. The step of switching to the series connection includes:

12. The method for controlling charging between battery packs according to claim 11, further comprising turning on third, fourth, and fifth switches of a battery connection section configured between the first and second battery packs and an external system to close the third, fourth, and fifth paths, and turning off the first and second switches to open the first and second paths, thereby connecting the first and second battery packs in series.