Battery pack and driving method thereof

Abstract

The invention provides a battery pack group and a driving method thereof. The battery pack group includes: a first battery pack including a first battery cell group in which a plurality of battery cells are connected in series, a first blocking relay, a first discharging relay, a first charging relay, and a battery management unit; the first blocking relay and the first discharging relay are connected in series to a discharging line of the first battery cell group, the first charging relay is connected to a charging line of the first battery cell group, and the battery management unit measures currents of the discharging line and the charging line. The first control circuit is used for controlling the operation of the first blocking relay, the first discharging relay and the first charging relay; and a second battery pack having the same structure as the first battery pack and connected in parallel with the first battery pack.

Description

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0177435, filed with the Korean Intellectual Property Office on December 8, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure relates to a battery pack and a driving method thereof. Background Art

[0003] Unlike primary batteries that cannot be recharged, secondary batteries are rechargeable and dischargeable. Low-capacity secondary batteries can be used in various portable small electronic devices (such as smartphones, feature phones, laptop computers, digital cameras, or camcorders), and high-capacity secondary batteries are widely used as power sources for motor drives (such as motor drives in hybrid vehicles or electric vehicles). These secondary batteries may include an electrode assembly having a positive electrode and a negative electrode, a case accommodating the electrode assembly, electrode terminals connected to the electrode assembly, and the like.

[0004] The above information disclosed in this background art section is only for enhancing the understanding of the background art of the present disclosure. Summary of the Invention

[0005] An embodiment includes a battery pack, the battery pack including: a first battery pack including a first battery cell group, a first cut-off relay, a first discharge relay, a first charge relay, and a battery management unit, in the first battery cell group, a plurality of battery cells are connected in series, the first cut-off relay and the first discharge relay are connected in series to a discharge line of the first battery cell group, the first charge relay is connected to a charge line of the first battery cell group, and the battery management unit measures currents of the discharge line and the charge line to control operations of the first cut-off relay, the first discharge relay, and the first charge relay; and a second battery pack having the same structure as the first battery pack and connected in parallel with the first battery pack.

[0006] The first battery pack may include a first resistor electrically connected between a negative electrode of the first battery cell group and a negative electrode terminal, and the battery management unit controls the operations of the first cut-off relay, the first discharge relay, and the first charge relay by measuring a current flowing through the first resistor.

[0007] The first battery pack may further include a first fuse electrically connected between a positive electrode of the first battery cell group and the first cut-off relay.

[0008] The first battery pack may further include a first diode, which is electrically connected between the first charging relay and the positive charging terminal and blocks current from flowing from the first charging relay to the positive charging terminal.

[0009] In the first battery pack, the first blocking relay, the first discharging relay, and the first charging relay may be N-type MOSFETs including a first electrode, a second electrode, and a control electrode. The first electrode may be the source electrode, the second electrode may be the drain electrode, and the control electrode may be the gate electrode.

[0010] In the first blocking relay of the first battery pack, the first electrode of the first blocking relay may be electrically connected to the positive electrode of the first battery cell group and the first electrode of the first charging relay. The second electrode of the first blocking relay may be electrically connected to the second electrode of the first discharging relay, and the control electrode of the first blocking relay may be electrically connected to the battery management unit.

[0011] In the first discharging relay of the first battery pack, the first electrode of the first discharging relay may be electrically connected to the positive discharging terminal of the discharging line. The second electrode of the first discharging relay may be electrically connected to the second electrode of the first blocking relay, and the control electrode of the first discharging relay may be electrically connected to the battery management unit.

[0012] In the first charging relay of the first battery pack, the first electrode of the first charging relay may be electrically connected to the positive electrode of the first battery cell group and the first electrode of the first blocking relay. The second electrode of the first charging relay may be electrically connected to the second electrode of the first diode, and the control electrode of the first charging relay may be electrically connected to the battery management unit.

[0013] The embodiment includes a driving method for the battery pack group. The driving method includes: if the first battery pack and the second battery pack are connected in parallel, the first discharging relay of the first battery pack and the second discharging relay of the second battery pack may be turned on, and the first blocking relay, the first charging relay of the first battery pack, and the second blocking relay and the second charging relay of the second battery pack may be turned off.

[0014] If an electronic device is connected to the input terminals and output terminals of the first battery pack and the second battery pack, the blocking relay of the battery pack with the larger charging voltage in the first battery pack and the second battery pack is turned on, so that the discharging current flowing through the discharging line is transmitted to the electronic device.

[0015] The battery management unit of the battery pack with the higher charging voltage among the first battery pack and the second battery pack may perform the following operations: when the measured discharge current flowing through the resistor remains higher than the reference current value for a reference time, turn on the corresponding blocking relay, so as to drive the electronic device through the voltage discharged from the battery pack.

[0016] If the charging voltages of the first battery pack and the second battery pack become the same, both the first battery pack and the second battery pack may be discharged.

[0017] If an electronic device is connected to the input terminals and output terminals of the first battery pack and the second battery pack, and the charging voltages of the first battery pack and the second battery pack are the same, both the first battery pack and the second battery pack may be discharged.

[0018] If a charger is connected to the input terminals and output terminals of the first battery pack and the second battery pack, the first discharge relay and the second discharge relay may be cut off, and the charging relay of the battery pack with the lower charging voltage among the first battery pack and the second battery pack may be turned on and charged through the charging current flowing through the charging line.

[0019] The battery management unit of the battery pack with the lower charging voltage among the first battery pack and the second battery pack may perform the following operations: if the measured charging current flowing through the resistor remains higher than the reference current value for a reference time, the charging relay may be turned on, so that the battery pack may be charged through the voltage applied from the charger.

[0020] If the charging voltages of the first battery pack and the second battery pack become the same, both the first battery pack and the second battery pack may be charged.

[0021] If an electronic device is connected to the input terminals and output terminals of the first battery pack and the second battery pack, and the charging voltages of the first battery pack and the second battery pack are the same, both the first battery pack and the second battery pack may be charged through the charger. Description of the Drawings

[0022] By referring to the accompanying drawings and describing the exemplary embodiments in detail, the features will become easy to understand for those of ordinary skill in the art. In the drawings:

[0023] Figure 1 is a structural diagram showing a battery pack group according to one or more embodiments of the present disclosure.

[0024] Figure 2 is a diagram showing in accordance with one or more embodiments Figure 1Structural diagram of current flow during the discharge operation after the first battery pack and the second battery pack shown are connected in parallel.

[0025] Figure 3A and Figure 3B is a graph showing the discharge current over time depending on the charging voltages of the first battery pack and the second battery pack according to one or more embodiments.

[0026] Figure 4 is a graph showing the charging current over time depending on the charging voltages of the first battery pack and the second battery pack according to one or more embodiments. Figure 1 Structural diagram of current flow during the charging operation after the first battery pack and the second battery pack shown are connected in parallel.

[0027] Figure 5 is a graph showing the charging current over time depending on the charging voltages of the first battery pack and the second battery pack according to one or more embodiments. Detailed Description

[0028] Example embodiments will be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in 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 exemplary embodiments to those skilled in the art.

[0029] In the drawings, the dimensions of layers and regions may be exaggerated for clarity. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being "under" another layer, it can be directly under, or one or more intervening layers may also be present. Additionally, it will be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals always refer to like elements.

[0030] Before presenting the following detailed description of the present disclosure, it should be noted that the terms and words used in the specification and claims should not be construed as limited to ordinary meanings or dictionary definitions, but should be interpreted in a sense and concept consistent with the technical concept of the present disclosure based on the inventor's ability to appropriately define the concept of the terms in order to describe the present disclosure in the best feasible manner. Therefore, the embodiments described in the specification and the configurations described in the drawings are only the most preferred embodiments of the present disclosure and do not represent all the technical concepts of the present disclosure. It will be understood that various equivalent alternatives and modifications may exist in place of them.

[0031] In addition, as used herein, the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0032] The identity of two objects cited in a comparison may mean that they are substantially the same. Thus, the phrase "substantially the same" may include cases where identity is considered low level in the relevant art, e.g., within a 5% deviation. In addition, when any parameter is said to be uniform in a given region, this may mean that the parameter is uniform from an average perspective.

[0033] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, unless otherwise defined, a first element, first component, first region, first layer, or first section described below may be referred to as a second element, second component, second region, second layer, or second section without departing from the spirit and scope of the present disclosure.

[0034] Throughout the specification, unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms.

[0035] The arrangement of any component "above (or below)" or "on top of (or under)" a component means that any component is placed in contact with the upper (or lower) surface of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

[0036] In addition, it will be understood that when an element is said to be "on", "connected to", or "coupled to" another element, these elements may be directly connected or coupled to each other, or there may be another intermediate element therebetween, or the corresponding elements may be connected, coupled, or linked to each other through another element.

[0037] As used herein, the term "and / or" includes any combination or all combinations of one or more of the associated listed items. In addition, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure". Expressions such as "at least one of..." modify the entire series of elements following the series of elements, rather than modifying individual elements within the series of elements.

[0038] Throughout the specification, unless otherwise defined, the expression "A and / or B" means A, B, or both A and B, and unless otherwise defined, the expression "C to D" means greater than or equal to C and less than or equal to D.

[0039] When the phrase "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group consisting of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the phrase can refer to any suitable combination or all suitable combinations.

[0040] As used herein, the term "use" may be considered synonymous with the term "utilize". As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not terms of degree, and are intended to account for the inherent deviations of measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0041] In the drawings, for clarity, the relative dimensions of elements, layers, and regions may be exaggerated. For ease of explanation, spatial relative terms (such as, "beneath", "below", "lower", "under", "above", "upper", etc.) may be used herein to describe the relationship of one element or feature to another element or feature as shown in the drawings. It will be understood that, in addition to the orientation shown in the drawings, spatial relative terms are intended to encompass different orientations of the device during use or operation. For example, if the device in the drawing is flipped, an element described as "beneath", "below", or "under" other elements or features will be oriented "above" the other elements or features.

[0042] Figure 1 is a structural diagram showing a battery pack group according to one or more embodiments of the present disclosure.

[0043] Figure 1 The battery pack group 100 of may include a first battery pack Pack1 and a second battery pack Pack2 connected in parallel with the first battery pack Pack1. Here, the first battery pack Pack1 and the second battery pack Pack2 may be discrete battery packs designed with the same structure and circuit. The battery pack group 100 can be used to increase the capacity of the battery pack by installing an additional battery pack in, for example, a vacuum cleaner or an electric bicycle equipped with one battery pack, but the application of the battery pack can vary.

[0044] The first battery pack Pack1 may include a first battery cell group Cell1 having a plurality of battery cells connected in series, a first discharge relay DFET1 and a first blocking relay BFET1 connected in series to a discharge line, and a first charging relay CFET1 and a first diode D1 connected in series to a charging line.

[0045] The first battery pack Pack1 may further include a first battery management unit C1 that controls the operations of the first discharge relay DFET1, the first blocking relay BFET1, and the first charging relay CFET1. The first battery cell group Cell1 may further include a first resistor Rs1 that detects the current flowing in the charge / discharge line, and a first fuse F1 connected in series to the first battery cell group Cell1.

[0046] The first battery pack Pack1 can supply current to the electronic device through input and output terminals that are the positive discharge terminal D+, the positive charging terminal C+, and the negative electrode terminals D- and C-, or can be charged by receiving current via a charger.

[0047] If the first battery pack Pack1 is discharged, current can flow between the positive discharge terminal D+ as the discharge line and the negative electrode terminals D- and C-. In addition, when the first battery pack Pack1 is charged, current can flow between the positive charging terminal C+ as the charging line and the negative electrode terminals D- and C-. The discharge line may have the negative electrode terminals D- and C-, the first resistor Rs1, the first battery cell group Cell1, the first fuse F1, the first blocking relay BFET1, the first discharge relay DFET1, and the positive discharge terminal D+ located in sequence therein. The charging line may have the positive charging terminal C+, the first diode D1, the first charging relay CFET1, the first fuse F1, the first battery cell group Cell1, the first resistor Rs1, and the negative electrode terminals D- and C- located in sequence therein. The sequential positions may be positions in the same direction as the current flow direction.

[0048] For example, if a charger is connected between the input and output terminals of the first battery pack Pack1, the first battery pack Pack1 can be charged through the charging line. When the electronic device connected to the input / output terminals is driven, the first battery pack Pack1 can supply voltage to the electronic device through discharge. If the first battery pack Pack1 is connected in parallel with the second battery pack Pack2, the positive discharge terminal D+, the positive charging terminal C+, and the negative electrode terminals D- and C- of the first battery pack Pack1 can be electrically connected to the second battery pack Pack2 respectively.

[0049] The driving method after the first battery pack Pack1 and the second battery pack Pack2 are connected in parallel will be described in detail.

[0050] Depending on the battery type, each battery cell included in the first battery cell group Cell1 can be a cylindrical battery cell, a prismatic battery cell, or a pouch battery cell. In the first battery cell group Cell1, the negative electrode can be electrically connected to the first electrode 1 of the first resistor Rs1, and the positive electrode can be electrically connected to the first electrode 1 of the first fuse F1. If current is supplied through the charging line, the first battery cell group Cell1 can be charged, and when current flows through the discharging line, the first battery cell group Cell1 can be discharged by supplying voltage to the electronic device.

[0051] The first electrode 1 of the first resistor Rs1 can be electrically connected to the negative electrode of the first battery cell group Cell1 and the first battery management unit C1, and the second electrode 2 can be connected to the negative electrode terminals D- and C- and the first battery management unit C1. The first battery management unit C1 can check whether current flows through the charging line and the discharging line through the first resistor Rs1.

[0052] In addition to including the first resistor Rs1 that detects the current flowing in the charging / discharging line, the first battery pack Pack1 can also include a detection device for detecting the state (voltage, current, temperature, etc.) of the first battery pack Pack1. The detection device can detect the state of each battery cell included in the first battery cell group Cell1 that constitutes the first battery pack Pack1. The first resistor Rs1 and the detection device can be electrically connected to the first battery management unit C1 and can transmit the state of the first battery pack Pack1 measured by the first resistor Rs1 and the detection device.

[0053] The first battery management unit C1 can control the operation of the first battery pack Pack1 by receiving the state of the first battery pack Pack1 sent from the first resistor Rs1 and the detection device. Based on the state information of the first battery pack Pack1 received from the first resistor Rs1 and the detection device, the first battery management unit C1 can monitor and calculate the state (voltage, current, temperature, state of charge (SOC), state of health (SOH), etc.) of the first battery cell group Cell1. In addition, the first battery management unit (C1) can perform control functions (such as temperature control, balance control, charge / discharge control, etc.) and protection functions (such as preventing over-discharge, over-charge, or over-current, short-circuit protection, fire extinguishing function, etc.).

[0054] The first battery management unit C1 can be electrically connected to the control electrodes of the first discharge relay DFET1, the first blocking relay BFET1, and the first charging relay CFET1 to control their operations. The first discharge relay DFET1, the first blocking relay BFET1, and the first charging relay CFET1 can be semiconductor switches, such as metal oxide semiconductor field effect transistors (MOSFETs). In some embodiments, the first discharge relay DFET1, the first blocking relay BFET1, and the first charging relay CFET1 can be N-type MOSFETs. In the following description, in each of the first discharge relay DFET1, the first blocking relay BFET1, and the first charging relay CFET1, the first electrode 1 can be the source electrode, the second electrode 2 can be the drain electrode, and the control electrode can be the gate electrode.

[0055] The first electrode 1 of the first discharge relay DFET1 can be electrically connected to the positive discharge terminal D+, the second electrode 2 of the first discharge relay DFET1 can be electrically connected to the second electrode 2 of the first blocking relay BFET1, and the control electrode of the first discharge relay DFET1 can be electrically connected to the first battery management unit C1. The first discharge relay DFET1 can be turned on or off under the control of the first battery management unit C1.

[0056] The first electrode 1 of the first blocking relay BFET1 can be electrically connected to the second electrode 2 of the first fuse F1 and the first electrode 1 of the first charging relay CFET1, the second electrode 2 of the first blocking relay BFET1 can be electrically connected to the second electrode 2 of the first discharge relay DFET1, and the control electrode of the first blocking relay BFET1 can be electrically connected to the first battery management unit C1. The first blocking relay BFET1 can be turned on or off under the control of the first battery management unit C1. The first blocking relay BFET1 and the first discharge relay DFET1 can connect or block the current flowing through the discharge line.

[0057] The first electrode 1 of the first charging relay CFET1 can be electrically connected to the second electrode 2 of the first fuse F1 and the first electrode 1 of the first blocking relay BFET1, the second electrode 2 of the first charging relay CFET1 can be electrically connected to the second electrode 2 of the first diode D1, and the control electrode of the first charging relay CFET1 can be electrically connected to the first battery management unit C1. The first charging relay CFET1 can be turned on or off under the control of the first battery management unit C1. The first charging relay CFET1 can connect or block the current flowing through the charging line.

[0058] The first electrode 1 of the first fuse F1 can be electrically connected to the positive electrode of the first battery cell group Cell1, and the second electrode 2 of the first fuse F1 can be connected to the first electrode 1 of the first charging relay CFET1 and the first electrode 1 of the first blocking relay BFET1. If an event occurs inside the first battery pack Pack1, the first fuse F1 can melt when an overcurrent flows and prevent current from flowing through the charging line and the discharging line.

[0059] The first electrode 1 of the first diode D1 can be electrically connected to the positive charging terminal C+, and the second electrode 2 of the first diode D1 can be electrically connected to the second electrode 2 of the first charging relay CFET1. The first electrode 1 of the first diode D1 can be an anode, and the second electrode 2 of the first diode D1 can be a cathode. The first diode D1 can prevent current from flowing from the first battery pack Pack1 to the positive charging terminal C+. That is, if the voltage of the first battery pack Pack1 is higher than the voltage of the second battery pack Pack2 and the first diode D1 is connected in parallel with the second battery pack Pack2, the first diode D1 can be set to block the inrush current from flowing to the second battery pack Pack2.

[0060] The first battery pack Pack1 can discharge by being combined with an electronic device as a single battery pack. The second battery pack Pack2 can be a separate battery pack designed with the same structure and circuit as that of the first battery pack Pack1. The second battery pack Pack2 can be an auxiliary battery pack for the electronic device and can be additionally installed in the electronic device combined with the first battery pack Pack1 and be electrically connected in parallel with the first battery pack Pack1. Of course, the reverse situation is also feasible. The electronic device can operate by receiving voltage from the first battery pack Pack1 or the second battery pack Pack2. That is, the first battery pack Pack1 and the second battery pack Pack2 can be used separately or in parallel to increase the capacity.

[0061] The first battery pack Pack1 and the second battery pack Pack2 can be electrically connected or disconnected, and if electrically connected, the charging voltage levels of the first battery pack Pack1 and the second battery pack Pack2 can be different. Of course, the charging voltage levels of the first battery pack Pack1 and the second battery pack Pack2 can alternatively be the same.

[0062] A charging or discharging driving method after the first battery pack Pack1 and the second battery pack Pack2 are connected in parallel in this way will be described in detail.

[0063] Figure 2 is a structural diagram showing the current flow during the discharging operation after Figure 1 the first battery pack Pack1 and the second battery pack Pack2 shown are connected in parallel according to one or more embodiments.Figure 3A is a graph showing the current values in the discharge lines of the first battery pack Pack1 and the second battery pack Pack2 over time when the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 are different from each other. More specifically, Figure 3A is a graph showing the change in the current values in the discharge lines of the first battery pack Pack1 and the second battery pack Pack2 over time when the charging voltage of the first battery pack Pack1 is greater than the charging voltage of the second battery pack Pack2. Figure 3B is a graph showing the current values in the discharge lines of the first battery pack Pack1 and the second battery pack Pack2 over time according to one or more embodiments when the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 are the same. Here, the charging voltage may be the state of charge (SOC) and / or open circuit voltage (OCV) of the battery pack.

[0064] When the first battery pack Pack1 and the second battery pack Pack2 are connected in parallel, the first battery pack Pack1 can turn on (connect) the first discharge relay DFET1 through the first battery management unit C1, and can turn off (disconnect) the first blocking relay BFET1 and the first charging relay CFET1. The second battery pack Pack2 can also turn on (connect) the second discharge relay DFET2 through the second battery management unit C2, and can turn off (disconnect) the second blocking relay BFET2 and the second charging relay CFET2.

[0065] The electronic device can be connected to the input terminals and output terminals of the first battery pack Pack1 and the second battery pack Pack2, and when the electronic device is driven, it can supply voltage to the electronic device by discharging the first battery pack Pack1 and / or the second battery pack Pack2.

[0066] After the first battery pack Pack1 and the second battery pack Pack2 are connected in parallel, in order to prevent inrush current from occurring in the initial stage due to the difference in charging voltage, only the discharge relay can be turned on in the state where the blocking relay and the charging relay are turned off. In addition, since the discharge relay is turned off, the voltage can only be supplied to the electronic device from the battery pack with the larger charging voltage among the first battery pack Pack1 and the second battery pack Pack2 or from both of these battery packs.

[0067] Referring to Figure 2 and Figure 3A , the case where the charging voltage of the first battery pack Pack1 can be greater than the charging voltage of the second battery pack Pack2 will be described.

[0068] To drive and supply voltage to an electronic device, at a first discharge starting point Td1 where the first battery pack Pack1 and / or the second battery pack Pack2 need to discharge, a first discharge current Id1 may flow through the discharge line of the first battery pack Pack1. In addition, a second discharge current Id2 may not flow through the discharge line of the second battery pack Pack2, and the second battery pack Pack2 has a charging voltage smaller than the charging voltage of the first battery pack Pack1.

[0069] The first discharge current Id1 can be measured by a first resistor Rs1 of the first battery pack Pack1 and sent to the first battery management unit C1. That is, the first battery management unit C1 can confirm that the first discharge current Id1 flows through the first resistor Rs1. If the first discharge current Id1 remains higher than the reference current value for a reference time, the first battery management unit C1 can turn on the first blocking relay BFET1 to allow the electronic device to be driven by the voltage discharged from the first battery pack Pack1. For example, the reference current value can be 200 mA, and the reference time can be 250 ms, but the reference current value and the reference time can vary in various ways according to the battery pack. That is, at the first discharge starting point Td1, only the first battery pack Pack1 with the larger charging voltage among the first battery pack Pack1 and the second battery pack Pack2 can be discharged.

[0070] In addition, if the charging voltage of the first battery pack Pack1 is greater than the charging voltage of the second battery pack Pack2, the electronic device can be driven by the first discharge current Id1 of the first battery pack Pack1 after the first discharge starting point Td1.

[0071] The first discharge current Id1 in the first battery pack Pack1 can sequentially flow through the negative electrode terminals D- and C-, the first resistor Rs1, the first battery cell group Cell1, the first fuse F1, the first blocking relay BFET1, the first discharge relay DFET1, and the positive discharge terminal D+.

[0072] As the charging voltage of the first battery pack Pack1 decreases due to discharge, and at a second discharge starting point Td2 where the charging voltage of the first battery pack Pack1 and the charging voltage of the second battery pack Pack2 become equal, a second discharge current Id2 may flow through the discharge line of the second battery pack Pack2. That is, at the second discharge starting point Td2, the first discharge current Id1 may flow through the discharge line of the first battery pack Pack1, and the second discharge current Id2 may flow through the discharge line of the second battery pack Pack2. The voltage from the first battery pack Pack1 and the second battery pack Pack2 can be supplied to the electronic device.

[0073] The driving method for allowing the second discharge current Id2 to flow through the discharge line of the second battery pack Pack2 can be similar to the driving method for allowing the first discharge current Id1 to flow through the discharge line of the first battery pack Pack1.

[0074] In this way, after the first battery pack Pack1 with a larger charging voltage in the first battery pack Pack1 and the second battery pack Pack2 discharges, when the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 become equal, the first battery pack Pack1 and the second battery pack Pack2 can discharge simultaneously. Of course, when the charging voltage of the second battery pack Pack2 is greater than the charging voltage of the first battery pack Pack1, the second battery pack Pack2 can discharge first. Then, when the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 become equal, the first battery pack Pack1 and the second battery pack Pack2 can discharge simultaneously.

[0075] Referring to Figure 2 and Figure 3B , the case where the charging voltage of the first battery pack Pack1 is the same as the charging voltage of the second battery pack Pack2 will be described.

[0076] In order to drive the electronic device and supply voltage, at the first discharge starting point Td1 where the first battery pack Pack1 and / or the second battery pack Pack2 needs to discharge, the first discharge current Id1 can flow through the discharge line of the first battery pack Pack1, and the second discharge current Id2 can flow through the discharge line of the second battery pack Pack2.

[0077] The driving method for allowing the first discharge current Id1 to flow through the discharge line of the first battery pack Pack1 and the driving method for allowing the second discharge current Id2 to flow through the discharge line of the second battery pack Pack2 can be similar to Figure 3A the driving method for allowing the first discharge current Id1 to flow through the discharge line of the first battery pack Pack1 described in the description of

[0078] That is to say, if the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 are equal, the electronic device can be driven by the first discharge current Id1 of the first battery pack Pack1 and the second discharge current Id2 of the second battery pack Pack2 after the first discharge starting point Td1.

[0079] Figure 4 is a structural diagram showing the current flow during the charging operation after the first battery pack Pack1 and the second battery pack Pack2 shown in Figure 1 are connected in parallel according to one or more embodiments. Figure 5is a graph showing the current value over time depending on the charging voltage in the charging lines of the first battery pack Pack1 and the second battery pack Pack2 when the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 are different from each other. More specifically, Figure 5 is a graph showing the current value over time depending on the charging voltage in the charging lines of the first battery pack Pack1 and the second battery pack Pack2 when the charging voltage of the first battery pack Pack1 is less than the charging voltage of the second battery pack Pack2.

[0080] If the first battery pack Pack1 and the second battery pack Pack2 are connected in parallel, the first battery pack Pack1 can turn on (connect) the first discharge relay DFET1 through the first battery management unit C1, and can turn off (disconnect) the first blocking relay BFET1 and the first charging relay CFET1. In addition, the second battery pack Pack2 can also turn on (connect) the second discharge relay DFET2 through the second battery management unit C2, and can turn off (disconnect) the second blocking relay BFET2 and the second charging relay CFET2.

[0081] The electronic device can be connected to the input terminals and output terminals of the first battery pack Pack1 and the second battery pack Pack2, and can supply voltage to the first battery pack Pack1 and the second battery pack Pack2 through a charger. If the charger is connected to the input terminals and output terminals of the first battery pack Pack1 and the second battery pack Pack2, the first discharge relay DFET1 and the second discharge relay DFET2 can be turned off.

[0082] When the charger is connected to the input terminals and output terminals, the first charging current Ic1 can flow through the charging line of the first battery pack Pack1 at the first charging start point Tc1 where it is necessary to charge the first battery pack Pack1 and / or the second battery pack Pack2. In some embodiments, the second charging current Ic2 may not flow through the charging line of the second battery pack Pack2, which has a charging voltage greater than the charging voltage of the first battery pack Pack1. In this case, the second diode D2 of the second battery pack Pack2 can prevent the reverse current with a larger charging voltage of the second battery pack Pack2 from being applied through the charging line of the first battery pack Pack1 connected in parallel.

[0083] In the first battery pack Pack1, the first charging current Ic1 can sequentially flow through the positive charging terminal C+, the first diode D1, the first charging relay CFET1, the first fuse F1, the first battery cell group Cell1, the first resistor Rs1, and the negative electrode terminals D- and C-.

[0084] The first charging current Ic1 can be measured through the first resistor Rs1 of the first battery pack Pack1 and sent to the first battery management unit C1. That is, the first battery management unit C1 can confirm that the first charging current Ic1 flows through the first resistor Rs1. If the first charging current Ic1 remains higher than the reference current value for the reference time, the first battery management unit C1 can turn on the first charging relay CFET1 to allow the voltage supplied from the charger to be sent to the first battery pack Pack1, so that the first battery pack Pack1 can be charged. In the exemplary embodiment, the reference current value can be 200 mA, and the reference time can be 250 ms. However, the reference current value and the reference time can vary in various ways according to the battery pack. That is, at the first charging start point Tc1, only the first battery pack Pack1 with the smaller charging voltage among the first battery pack Pack1 and the second battery pack Pack2 can be charged by the current supplied from the charger.

[0085] As the charging voltage of the first battery pack Pack1 increases due to charging, and at the second charging start point Tc2 where the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 become equal, the second charging current Ic2 can flow through the charging line of the second battery pack Pack2. That is, at the second charging start point Tc2, the first charging current Ic1 can flow through the charging line of the first battery pack Pack1, and the second charging current Ic2 can flow through the charging line of the second battery pack Pack2. When the charging voltages of the first battery pack Pack1 and the second battery pack Pack2 are equal, the first battery pack Pack1 and the second battery pack Pack2 can be charged simultaneously by the charger.

[0086] The present disclosure relates to a battery pack group and a driving method thereof, in which two battery packs can be used by parallel connection to increase the capacity, and even if the charging voltages of the two battery packs are different, charging and discharging can be simultaneously achieved by allowing the two battery packs to have the same charging voltage through sequential discharging or charging.

[0087] Exemplary embodiments have been disclosed herein, and although specific terms have been employed, they are used and interpreted in a general and descriptive sense only and not for purposes of limitation. In some cases, as will be readily understood by those of ordinary skill in the art, unless specifically stated otherwise, features, characteristics, and / or elements described in connection with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Accordingly, those skilled in the art will understand that various changes may be made in form and detail without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. A battery pack, comprising: A first battery pack, comprising a first battery cell group, a first blocking relay and a first discharging relay, a first charging relay and a battery management unit, wherein a plurality of battery cells are connected in series in the first battery cell group, the first blocking relay and the first discharging relay are connected in series to a discharging line of the first battery cell group, the first charging relay is connected to a charging line of the first battery cell group, and the battery management unit measures currents of the discharging line and the charging line to control operations of the first blocking relay, the first discharging relay and the first charging relay; as well as The second battery pack has the same structure as the first battery pack and is connected in parallel with the first battery pack.

2. The battery pack according to claim 1, wherein: The first battery pack includes a first resistor electrically connected between a negative electrode and a negative electrode terminal of the first battery cell group, and the battery management unit controls the operations of the first blocking relay, the first discharging relay, and the first charging relay by measuring a current flowing through the first resistor.

3. The battery pack according to claim 1, wherein: The first battery pack further includes a first fuse electrically connected between a positive electrode of the first battery cell group and the first blocking relay.

4. The battery pack according to claim 1, wherein: The first battery pack also includes a first diode that is electrically connected between the first charging relay and a positive charging terminal and blocks current from flowing from the first charging relay to the positive charging terminal.

5. The battery pack according to claim 4, wherein: In the first battery pack, the first blocking relay, the first discharging relay and the first charging relay are N-type MOSFETs including a first electrode, a second electrode and a control electrode, and the first electrode is a source electrode, the second electrode is a drain electrode, and the control electrode is a gate electrode.

6. The battery pack according to claim 5, wherein: In the first blocking relay of the first battery pack, a first electrode of the first blocking relay is electrically connected to a positive electrode of the first battery cell group and a first electrode of the first charging relay, a second electrode of the first blocking relay is electrically connected to a second electrode of the first discharging relay, and the control electrode of the first blocking relay is electrically connected to the battery management unit.

7. The battery pack according to claim 6, wherein: In the first discharge relay of the first battery pack, a first electrode of the first discharge relay is electrically connected to a positive discharge terminal of the discharge line, a second electrode of the first discharge relay is electrically connected to a second electrode of the first blocking relay, and the control electrode of the first discharge relay is electrically connected to the battery management unit.

8. The battery pack according to claim 5, wherein: In the first charging relay of the first battery pack, a first electrode of the first charging relay is electrically connected to a positive electrode of the first battery cell group and a first electrode of the first blocking relay, a second electrode of the first charging relay is electrically connected to a second electrode of the first diode, and a control electrode of the first charging relay is electrically connected to the battery management unit.

9. A driving method of a battery pack according to claim 1, the driving method comprising: When the first battery pack and the second battery pack are connected in parallel, the first discharging relay of the first battery pack and the second discharging relay of the second battery pack are turned on, and the first blocking relay and the first charging relay of the first battery pack and the second blocking relay and the second charging relay of the second battery pack are turned off.

10. The driving method according to claim 9, wherein: When an electronic device is connected to the input terminals and output terminals of the first and second battery packs, a blocking relay of the battery pack having a larger charging voltage among the first and second battery packs is turned on, so that a discharge current flowing through a discharge line is transmitted to the electronic device.

11. The driving method according to claim 10, wherein: The battery management unit of the battery pack having a larger charging voltage among the first and second battery packs performs the following operations: when the measured discharge current flowing through the resistor remains higher than a reference current value for a reference time, the blocking relay is turned on, thereby driving the electronic device by the voltage discharged from the battery pack.

12. The driving method according to claim 10, wherein: If the charging voltages of the first battery pack and the second battery pack become the same, both the first battery pack and the second battery pack are discharged.

13. The driving method according to claim 9, wherein: If an electronic device is connected to the input terminal and the output terminal of the first battery pack and the second battery pack, and the charging voltages of the first battery pack and the second battery pack are the same, both the first battery pack and the second battery pack are discharged.

14. The driving method according to claim 9, wherein: If a charger is connected to input terminals and output terminals of the first and second battery packs, the first and second discharge relays are turned off, and the charging relay of the battery pack having a smaller charging voltage among the first and second battery packs is turned on and charged by the charging current flowing through the charging line.

15. The driving method according to claim 14, wherein: The battery management unit of the battery pack having a smaller charging voltage among the first and second battery packs performs the following operations: when the measured charging current flowing through the resistor remains higher than a reference current value for a reference time, the charging relay is turned on, thereby charging the battery pack by the voltage applied from the charger.

16. The driving method according to claim 14, wherein: If the charging voltages of the first battery pack and the second battery pack become the same, both the first battery pack and the second battery pack are charged.

17. The driving method according to claim 14, wherein: If an electronic device is connected to the input terminal and the output terminal of the first battery pack and the second battery pack, and the charging voltages of the first battery pack and the second battery pack are the same, both the first battery pack and the second battery pack are charged by the charger.

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