KR20160091568A - Battery Pack Comprising Control Unit Determining Abnormal State of Battery Units - Google Patents

Battery Pack Comprising Control Unit Determining Abnormal State of Battery Units Download PDF

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KR20160091568A
KR20160091568A KR1020150011836A KR20150011836A KR20160091568A KR 20160091568 A KR20160091568 A KR 20160091568A KR 1020150011836 A KR1020150011836 A KR 1020150011836A KR 20150011836 A KR20150011836 A KR 20150011836A KR 20160091568 A KR20160091568 A KR 20160091568A
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South Korea
Prior art keywords
battery pack
voltage
battery
current
pack according
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KR1020150011836A
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Korean (ko)
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이연옥
김수제
송인이
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주식회사 엘지화학
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Priority to KR1020150011836A priority Critical patent/KR20160091568A/en
Publication of KR20160091568A publication Critical patent/KR20160091568A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/18—Status alarms
    • G08B21/185—Electrical failure alarms
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/18—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for batteries; for accumulators

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Secondary Cells (AREA)

Abstract

The present invention relates to a battery pack including two or more battery units connected in series, the battery pack comprising: at least two voltage detectors that are one-to-one associated with the battery units and repeatedly measure a voltage; And a control unit for outputting a control signal based on the voltage sent from the voltage detecting units, wherein when the battery pack is being discharged, the n-th (n is an integer of 2 or more) (N-1) -th measured voltage of the battery unit is subtracted from the n-th measured voltage when the battery pack is being charged, if the difference in the discharge voltage obtained by subtracting the And when the voltage difference exceeds the reference voltage, it is determined that the battery pack is in an abnormal state.

Description

A battery pack (Battery Pack Comprising Control Unit Determining Abnormal State of Battery Units) that includes a controller that determines an abnormal state of a plurality of battery units,

The present invention relates to a battery pack including a control unit for determining an abnormal state of a plurality of battery units.

Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative energy or clean energy is increasing. As a part of this, the most active field of research is electric power generation and storage.

At present, a typical example of an electrochemical device utilizing such electrochemical energy is a secondary battery, and the use area thereof is gradually increasing.

Particularly, there is an increasing demand for a large-capacity secondary battery used as a power source for mobile devices and medium and large-sized devices. In order to meet such a demand, the use of a battery pack in which a plurality of battery cells are electrically connected is increasing.

Since the battery pack is preferably manufactured with a small size and a weight as much as possible, a prismatic battery, a pouch-type battery, and the like, which can be charged with a high degree of integration and have a small weight to capacity ratio, are mainly used as the battery cells of the middle- or large-sized battery pack. Particularly, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a great deal of attention due to its advantages such as low weight and low manufacturing cost.

On the other hand, lithium secondary batteries have a variety of combustible materials, and they have a disadvantage in terms of safety because of the danger of overheating, overcurrent, other physical external impact, and the like. Therefore, in the case of a battery pack or a battery module including a plurality of such secondary batteries, a control unit or a battery management system (BMS) may be used to manage the battery safely and efficiently.

The controller controls voltage and current of the battery pack, and controls the battery pack to be safely maintained based on the information. In particular, the controller controls the battery pack based on the information of the current and voltage measured during charging and discharging, abnormal state.

However, when a plurality of battery units are included in the battery pack, the configuration of the battery pack becomes complicated due to a sensing line for sensing information on each battery unit, and the control logic becomes complicated.

The accuracy of the determination of the abnormal state is rather lowered due to the complicated control logic, and a problem that the battery pack malfunctions and safety are lowered have occurred.

Therefore, it is necessary to develop a technology that simplifies the control logic of the battery pack, reduces malfunction, and improves safety.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and have found that when the battery pack is discharging, the discharge voltage difference obtained by subtracting the (n-1) And determines that the battery pack is in an abnormal state if the voltage exceeds the reference voltage and determines that the battery pack is in an abnormal state if the difference between the charging voltage obtained by subtracting the nth measured voltage from the (n-1) The present inventors have confirmed that the above-described problems can be solved at the same time and accomplished the present invention.

Accordingly, a battery pack according to the present invention is a battery pack including at least two battery units connected in series, the battery pack comprising: at least two voltage detectors for one-to-one correspondence with the battery units to repeatedly measure a voltage; And a control unit for outputting a control signal based on the voltage sent from the voltage detecting units, wherein when the battery pack is being discharged, the n-th (n is an integer of 2 or more) (N-1) -th measured voltage of the battery unit is subtracted from the n-th measured voltage when the battery pack is being charged, if the difference in the discharge voltage obtained by subtracting the And judges the abnormal state if the voltage difference exceeds the reference voltage.

That is, the control unit uses the property that the voltage of the normal battery unit does not rise when the battery pack is discharging, and the voltage of the normal battery unit does not fall when the battery pack is being charged.

If the voltage of the battery unit does not rise or change when the battery pack is discharging, this may be caused by the fact that the electric circuit of the battery unit is disconnected and the voltage does not change, or a balance between the battery unit and another battery unit It can be judged that the voltage slightly increases.

Further, if the voltage of the battery unit does not drop or change when the battery pack is being charged, it can be determined that the internal circuit is disconnected or short-circuited on the principle similar to the case of discharging.

Therefore, the control unit accurately determines the abnormal state of the battery pack only by a simple control logic for comparing the n-th measured voltage measured later with the n-1th voltage measured immediately before, based on the measurement order for each battery unit .

Since the abnormal state is determined by the simple control logic, the risk of malfunction of the control unit is reduced and the safety of the battery pack can be improved.

Further, since the voltage detecting units and the battery units are corresponded one to one so that the voltage of each battery unit can be measured, the sensing line in the battery pack can be simplified.

The control unit determines that the discharge voltage difference or the charge voltage difference is equal to or greater than the reference voltage. The control unit may adjust the reference voltage to improve the reliability of the determination of the abnormal condition or to improve the sensitivity of the abnormal condition determination.

In one specific example, the reference voltage may be in the range of 0% to 5% of the full charge voltage of the battery unit, and more specifically, in the range of 0.01% to 3%.

When the reference voltage is 0% of the full charge voltage, it is possible to determine the abnormal state, except for the case where the discharge voltage difference or the charge voltage difference is negative, so that the sensitivity of the abnormal state determination can be improved. The reliability of the abnormal state judgment can be improved.

Therefore, the safety of the battery pack can be improved by adjusting the reference voltage within this range.

It is important to determine whether the battery pack is being charged or discharged, in order to further ensure the reliability of the abnormality determination of the controller. In one specific example, the battery pack may include a charging current or a discharging current of the battery pack. And may further include a current detection unit for repeatedly measuring.

The control unit may determine whether or not the respective battery units are abnormal when the charging current or the discharging current is equal to or greater than the reference current based on the current sent from the current detecting unit.

Even when the battery pack is in normal operation, a minute current can be detected in the current detection unit due to a change in external conditions such as temperature. In this case, since the battery pack is not being charged or discharged, the control unit needs to determine whether the battery units are abnormal It is possible to prevent unnecessary determination of an abnormal state by setting the reference current to a value within a certain range.

For example, the reference current may be 1 mA to 300 mA, specifically 10 mA to 100 mA, more preferably 10 mA to 100 mA, for example, , More specifically in the range of 20 mA to 80 mA.

On the other hand, when the discharge is suddenly stopped during the discharge, the voltage measured later temporarily rises and the difference of the discharge voltage may exceed the reference voltage.

This phenomenon may occur even during normal operation of the battery pack. To prevent such a phenomenon from being determined as an abnormal state, it is determined that the discharge of the battery pack is stopped when the measured current is decreased, It is determined that the battery pack continues to discharge, and the abnormal state can be determined using the control unit only when the discharge continues.

Therefore, the control unit of the battery pack may be configured to determine an abnormal state when the n-th measurement current is equal to or greater than the (n-1) th measurement current, and the measurement current includes a charge current as well as a discharge current.

With this configuration, it is possible to prevent unnecessary determination of an abnormal state when charging is completed by using a principle similar to that at the time of charging even when charging.

In one specific example, the voltage detecting units and the current detecting unit can periodically measure a voltage or a current and can measure a voltage or a current in an interval of 0.1 to 60 seconds, more specifically, 0.1 to 10 seconds have.

If the time interval is less than 0.1 second, it may be determined that the battery pack is malfunctioning even during an instantaneous abnormal voltage, so that reliability of the determination of the abnormal condition may deteriorate. If the time interval is longer than 60 seconds, The safety of the battery pack may be deteriorated.

The sensitivity and reliability of the abnormal state determination can be controlled by adjusting the time interval. When the time interval and the reference voltage are adjusted in correlation with each other, the accuracy of the abnormal state determination can be further improved.

On the other hand, when the controller determines that the battery pack is in an abnormal state, the control unit outputs a control signal to control the battery pack to stop operation, thereby securing the safety of the battery pack. For example, The battery pack may be controlled so as to be in a protection state in which charging or discharging is temporarily stopped, or in a case where it is determined that the abnormal state of the battery pack is serious, the internal circuit may be disconnected to be in a state of permanent failure.

In one specific example, the control unit may control the battery pack to stop operating by outputting a control signal when it is determined that the battery pack is abnormal in succession over the reference number of times. In this case, Increasing the number of times can improve the reliability of the determination of the abnormal state, and decreasing the reference number can improve the sensitivity and secure the safety.

For example, the reference frequency may be set in a range of 1 to 10 times, more specifically, 2 to 10 times, more specifically, 3 to 6 times.

The control unit may be configured to transmit an abnormality notification signal to the external device when it is determined that the control unit is in an abnormal state, thereby detecting an abnormal state of the battery pack in the external device, It is possible to improve the safety in use.

In one specific example, the battery unit may be a battery cell or a bank in which two or more battery cells are connected in parallel.

The capacity of a required battery pack is different depending on the type of device. Particularly, in view of the recent trend of increasing capacity of battery packs used in mobile devices and mid-sized devices, a large capacity battery pack is generally required. It may be preferable from the viewpoint of capacity to use a series connection of banks in which battery cells are connected in parallel rather than connecting them.

In one specific example, the battery cell may be a lithium secondary battery in which the electrode assembly is sealed inside the battery case together with the electrolyte solution.

The present invention also provides a method of controlling such a battery pack, and a control method of the battery pack according to the present invention

(a) repeatedly measuring a voltage of battery units included in the battery pack using voltage detecting units;

(b) if the discharge voltage difference obtained by subtracting the (n-1) th measured voltage from the nth measured voltage of the battery unit when the battery pack is discharging is greater than the reference voltage, based on the voltage sent from the voltage detectors using the control unit Determining an abnormal state and determining that the charging voltage difference, which is the n-th measured voltage subtracted from the n-1th measured voltage of the battery unit when the battery pack is being charged, is abnormal; And

and (c) outputting a control signal to stop the operation of the battery pack when the controller determines that the battery pack is in an abnormal state.

In one specific example, the battery pack further includes a current detection unit for repeatedly measuring a charging current or a discharging current of the battery pack, wherein, in the step (b) It is possible to judge whether or not the battery units are abnormal.

In one specific example, in the case (c), when the control unit determines that the control unit is in an abnormal state, it may transmit an abnormality notification signal to the external device.

The present invention also provides a device including the battery pack as a power source.

The device can be, for example, a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug-in hybrid electric vehicle, A cart, or a system for power storage, but it is not limited to these.

Since the structure and manufacturing method of such a device are well known in the art, a detailed description thereof will be omitted herein.

Hereinafter, other components of the secondary battery will be described.

The secondary battery may have a structure in which an electrode assembly in which a separation membrane is interposed between an anode and a cathode is sealed inside the battery case together with an electrolyte solution.

The positive electrode may be prepared, for example, by applying a positive electrode mixture mixed with a positive electrode active material, a conductive material and a binder to a positive electrode collector, and if necessary, a filler may further be added to the positive electrode mixture.

The cathode current collector generally has a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel A surface treated with carbon, nickel, titanium, silver or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The cathode active material may be, for example, a layered compound such as lithium cobalt oxide (LiCoO 2 ) or lithium nickel oxide (LiNiO 2 ) or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li 1 + x Mn 2 -x O 4 (where x is 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2 and the like; Lithium copper oxide (Li 2 CuO 2 ); Vanadium oxides such as LiV 3 O 8 , LiV 3 O 4 , V 2 O 5 and Cu 2 V 2 O 7 ; A Ni-site type lithium nickel oxide expressed by the formula LiNi 1-x M x O 2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula LiMn 2-x M x O 2 ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li 2 Mn 3 MO 8 (where, M = Fe, Co, Ni, Cu, or Zn); LiMn 2 O 4 in which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe 2 (MoO 4 ) 3 , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

On the other hand, the negative electrode is manufactured by applying, drying and pressing an anode active material on an anode current collector, and may optionally further include a conductive material, a binder, a filler, and the like as described above.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

The negative electrode active material may include, for example, carbon such as non-graphitized carbon or graphite carbon; Li x Fe 2 O 3 (0≤x≤1 ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x < Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; SnO, SnO 2, PbO, PbO 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi 2 O 5 ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m, and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The structure of the electrode assembly is not particularly limited as long as it is a structure capable of generating a gas trap upon charging and discharging. For example, when a plurality of positive electrodes and negative electrodes cut in a predetermined size unit are sequentially (Stacked type) electrode assembly in which a positive electrode and a negative electrode are laminated in a stacked state with a separator interposed therebetween, or a stacked-folded electrode having a structure in which a bi- Assembly or the like.

The secondary battery may be a prismatic secondary battery in which an electrode assembly is embedded in a square metal can, or a pouch type secondary battery in which an electrode assembly is embedded in a case of a laminate sheet including a resin layer and a metal layer.

The laminate sheet may be an aluminum laminate sheet. Specifically, a resin outer layer having excellent durability is added to one surface (outer surface) of the metal barrier layer, and a thermally fusible resin sealant layer is provided on the other surface Structure.

Since the resin outer layer has excellent resistance from the external environment, it is necessary to have a tensile strength and weather resistance of a predetermined level or higher. In this respect, polyethylene terephthalate (PET) and stretched nylon film can be preferably used as the polymer resin of the resin outer layer.

The metal barrier layer may include aluminum or aluminum alloy so as to exhibit a function of improving the strength of the battery case, in addition to a function of preventing foreign matter such as gas or moisture from leaking or leaking.

As the polymer resin of the resin sealant layer, a polyolefin resin having a low heat absorbing property (heat adhesion property) and low hygroscopicity in order to suppress penetration of an electrolyte solution and not being swollen or eroded by an electrolytic solution is preferably used And more particularly, lead-free polypropylene (CPP) may be used.

In general, a polyolefin resin such as polypropylene has a low adhesive force with a metal. Therefore, as a method for improving the adhesion with the metal barrier layer, more specifically, an adhesive layer is additionally provided between the metal layer and the resin sealant layer, And blocking characteristics can be improved. Examples of the material of the adhesive layer include a urethane-based material, an acryl-based material, a composition containing a thermoplastic elastomer, and the like, but are not limited thereto.

The electrolytic solution contains a lithium salt, and examples of the electrolytic solution include non-aqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, and the like.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer containing an ionic dissociation group and the like may be used.

Examples of the inorganic solid electrolyte include Li 3 N, LiI, Li 5 NI 2 , Li 3 N-LiI-LiOH, LiSiO 4 , LiSiO 4 -LiI-LiOH, Li 2 SiS 3 , Li 4 SiO 4 , Nitrides, halides and sulfates of Li such as Li 4 SiO 4 -LiI-LiOH and Li 3 PO 4 -Li 2 S-SiS 2 can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide.

In some cases, for the purpose of improving the charge-discharge characteristics and flame retardancy of the electrolytic solution, it is possible to use, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride, May be added. In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene Carbonate, PRS (Propene sultone), and the like.

In one specific example, LiPF 6, LiClO 4, LiBF 4, LiN (SO 2 CF 3) 2 , such as a lithium salt, a highly dielectric solvent of DEC, DMC or EMC Fig solvent cyclic carbonate and a low viscosity of the EC or PC of And then adding it to a mixed solvent of linear carbonate to prepare a lithium salt-containing nonaqueous electrolyte.

Such a method of manufacturing a secondary battery is well known in the art, so a detailed description thereof will be omitted herein.

As described above, the battery pack according to the present invention includes a control unit for determining an abnormal state of the battery units, so that the control logic of the battery pack is simple, the malfunction of the control unit is reduced, and the safety of the battery pack is improved There is.

1 is a schematic view showing a battery pack according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 1 schematically shows a battery pack according to an embodiment of the present invention.

Referring to FIG. 1, a battery pack 100 according to the present invention includes three banks 110, 120, and 130, three voltage detectors 210, 220, and 230, a current detector 300, ), And two external input / output terminals 510 and 520.

Specifically, the battery pack 100 supplies power to an external device (not shown) through the external input / output terminals 510 and 520 or receives power from the charger.

The banks 110, 120, and 130 are connected in series with each other. The first bank 110 includes two battery cells 111 and 112. The battery cells 111 and 112 are connected in parallel and the second and third banks 120 and 130 are also connected in parallel. And has a structure similar to that of the first bank 110.

The voltage detectors 210, 220 and 230 are associated one-to-one with the banks 110, 120 and 130 and repeatedly measure the voltages of the banks 110, 120 and 130, do.

The current detector 300 is connected in series with the banks 110, 120 and 130 and repeatedly measures the charging current or the discharging current of the battery pack 100 and transmits it to the controller 400. [

The control unit 400 determines an abnormal state of the banks 110, 120, and 130 based on the voltage and current sent from the voltage detecting units 210, 220, and 230 and the current detecting unit 300, When it is determined that the battery pack 100 is not operating, the controller 100 outputs a control signal to stop the operation of the battery pack 100 and transmit a notification signal to an external device (not shown).

In one example, the full charge voltage of the banks 110, 120 and 130 is 4.2 V, the measurement periods of the voltage detectors 210, 220 and 230 and the current detector 300 are 1 second, the reference voltage is 100 mV (About 2.4% of the full charge voltage), the reference current is 50 mA, and the reference frequency is 4 times.

Since the voltage and current are measured at intervals of 1 second, the voltage and current are measured 30 times each for 30 seconds of discharge.

If the fifth measurement current is 50 mA, the sixth measurement current is 110 mA, and the seventh measurement current is 120 mA, the control unit 400 determines that the measurement current is less than the reference current in the fifth period after the discharge of the battery pack 100, It is determined that the abnormal state is not detected at the sixth, seventh, and so on.

Further, since the seventh measured current is equal to or higher than the sixth measured current, the abnormal state of the banks 110, 120, and 130 is determined based on the fact that the discharge of the battery pack 100 is not interrupted and the discharge progresses normally.

When the sixth measured voltage of the first bank 110 during discharge is 3.5 V, the seventh measured voltage is 3.3 V, and the eighth measured voltage is 3.45 V, the discharge voltage difference obtained by subtracting the sixth measured voltage from the seventh measured voltage The control unit 400 does not judge the abnormal state because it is less than the reference voltage, but the difference in the discharge voltage obtained by subtracting the seventh measured voltage from the eighth measured voltage exceeds the reference voltage by 0.150 mV, State.

In this case, the controller 400 determines the abnormal state of the first bank 110 in chronological order. When the controller 400 determines that the abnormal state of the first bank 110 is abnormal for four or more times, 100, and sends a notification signal to the external device, thereby improving the safety of the battery pack 100. [

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (22)

1. A battery pack comprising at least two battery units connected in series,
Two or more voltage detectors corresponding to the battery units one-to-one and repeatedly measuring a voltage; And
A control unit for outputting a control signal based on the voltage sent from the voltage detecting units;
/ RTI >
If the difference between the discharge voltages obtained by subtracting the (n-1) th measurement voltage from the n-th measurement voltage (where n is an integer of 2 or more) of the battery unit is greater than the reference voltage when the battery pack is discharging, And determines that the battery pack is in an abnormal state if the difference between the charging voltage obtained by subtracting the n-th measured voltage from the (n-1) -th measured voltage of the battery unit exceeds the reference voltage when the battery pack is being charged. The battery pack according to claim 1, wherein the battery unit is a battery cell or a bank in which two or more battery cells are connected in parallel. The battery pack according to claim 1, wherein the reference voltage is within a range of 0% to 5% of a full charge voltage of the battery unit. The battery pack according to claim 3, wherein the reference voltage is within a range of 0.01% to 3% of a full charge voltage of the battery unit. The battery pack according to claim 1, further comprising a current detector for repeatedly measuring a charging current or a discharging current of the battery pack. The battery pack according to claim 5, wherein the control unit of the battery pack determines whether or not each of the battery units is abnormal when the charging current or the discharging current is equal to or greater than the reference current based on the current sent from the current detecting unit pack. The battery pack according to claim 6, wherein the reference current is in a range of 1 mA to 300 mA. The battery pack according to claim 6, wherein the reference current is in a range of 10 mA to 100 mA. The battery pack according to claim 6, wherein the control unit of the battery pack determines an abnormal state when the n-th measurement current is equal to or greater than the (n-1) -th measurement current. The battery pack according to claim 1 or 5, wherein the voltage detecting units and the current detecting unit periodically measure a voltage or a current. The battery pack according to claim 10, wherein the voltage detecting units and the current detecting unit measure a voltage or a current at intervals of 0.1 to 60 seconds. The battery pack according to claim 1, wherein the control unit outputs a control signal to stop the operation of the battery pack when determining that the battery pack is in an abnormal state. The battery pack according to claim 1, wherein the control unit outputs a control signal to stop the operation of the battery pack when the control unit determines that the battery pack is in abnormal state continuously for more than the reference number of times. 14. The battery pack according to claim 13, wherein the reference frequency is set in a range of 1 to 10 times. 14. The battery pack according to claim 13, wherein the reference frequency is set in a range of 3 to 6 times. 2. The battery pack according to claim 1, wherein when the controller determines that the controller is in an abnormal state, the controller transmits an abnormality notification signal to the external device. The battery pack according to claim 2, wherein the battery cell is a lithium secondary battery in which an electrode assembly is sealed inside a battery case together with an electrolyte solution. A control method for a battery pack according to claim 1,
(a) repeatedly measuring a voltage of battery units included in the battery pack using voltage detecting units;
(b) if the discharge voltage difference obtained by subtracting the (n-1) th measured voltage from the nth measured voltage of the battery unit when the battery pack is discharging is greater than the reference voltage, based on the voltage sent from the voltage detectors using the control unit Determining an abnormal state and determining that the charging voltage difference, which is the n-th measured voltage subtracted from the n-1th measured voltage of the battery unit when the battery pack is being charged, is abnormal; And
(c) outputting a control signal to stop the operation of the battery pack when the controller determines that the battery pack is in an abnormal state;
And a control unit for controlling the battery pack. 19. The battery pack according to claim 18, wherein the battery pack further comprises a current detector for repeatedly measuring a charging current or a discharging current of the battery pack,
Wherein, in the step (b), the control unit determines whether or not each of the battery units is abnormal based on the current sent from the current detection unit. 19. The control method of a battery pack according to claim 18, wherein, in the step (c), when the control unit judges an abnormal state, the abnormality notification signal is transmitted to the external device. A device comprising the battery pack according to claim 1 as a power source. 22. The device of claim 21, wherein the device is a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug- , Or a system for power storage.
KR1020150011836A 2015-01-26 2015-01-26 Battery Pack Comprising Control Unit Determining Abnormal State of Battery Units KR20160091568A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101960923B1 (en) * 2018-10-29 2019-03-21 주식회사 거림 Charging/discharging measurement device for battery
WO2020226308A1 (en) * 2019-05-03 2020-11-12 주식회사 엘지화학 Apparatus and method for diagnosing battery cell

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101960923B1 (en) * 2018-10-29 2019-03-21 주식회사 거림 Charging/discharging measurement device for battery
WO2020226308A1 (en) * 2019-05-03 2020-11-12 주식회사 엘지화학 Apparatus and method for diagnosing battery cell
US11796605B2 (en) 2019-05-03 2023-10-24 Lg Energy Solution, Ltd. Battery cell diagnostic device and method

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