Method for detecting dielectric breakdown in battery module, battery system and vehicle comprising such battery system

Abstract

The present disclosure relates to a method for detecting the occurrence of dielectric breakdown in a battery module. The present disclosure also relates to a method for disconnecting a battery module from a load upon detection of a dielectric breakdown in the battery module. Furthermore, the present disclosure relates to a battery system having a battery module configured to perform the disclosed method for detecting the occurrence of a dielectric breakdown in a battery module and / or configured to perform the disclosed method for disconnecting a battery module from a load upon detection of a dielectric breakdown in a battery module. Furthermore, the present disclosure relates to a vehicle comprising at least one battery system according to the present disclosure.

Description

Technical Field

[0001] The present disclosure relates to a battery system and method for detecting dielectric breakdown in a battery module and for disconnecting the battery module from a load thereon, and to a vehicle including the battery system. Background Art

[0002] In recent years, vehicles for transporting goods and people have been developed that use electricity as a power source. Such electric vehicles are cars that are propelled by an electric motor using energy stored in a rechargeable battery. Electric vehicles may be powered solely by batteries, or may be in the form of hybrid vehicles powered by, for example, a gasoline generator or a hydrogen fuel cell. Furthermore, the vehicle may include a combination of an electric motor and a conventional internal combustion engine.

[0003] Typically, an electric vehicle battery (EVB) or traction battery is a battery used to power the propulsion of a battery electric vehicle (BEV). Electric vehicle batteries differ from starting, lighting, and ignition batteries in that they are designed to provide power for a sustained period of time. A rechargeable or secondary battery differs from a primary battery in that it can be repeatedly charged and discharged, whereas the latter only provides an irreversible conversion of chemical energy to electrical energy. Low-capacity rechargeable batteries can be used as a power source for small electronic devices such as cellular phones, notebook computers, and video cameras, while high-capacity rechargeable batteries can be used as a power source for electric vehicles and hybrid vehicles, among others.

[0004] Typically, a rechargeable battery includes an electrode assembly, a housing for accommodating the electrode assembly, and an electrode terminal electrically connected to the electrode assembly, wherein the electrode assembly includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. An electrolyte solution is injected into the housing to enable the battery to be charged and discharged via an electrochemical reaction of the positive electrode, the negative electrode, and the electrolyte solution. The shape of the housing (e.g., cylindrical or rectangular) may depend on the intended purpose of the battery. Lithium-ion (and similar lithium polymer) batteries are well known for their use in laptop computers and consumer electronics, and dominate the latest developed electric vehicles.

[0005] A rechargeable battery can be used as a battery module formed by combining a plurality of unit battery cells in series and / or in parallel to provide high energy content, for example, for motor driving of a hybrid vehicle. That is, a battery module is formed by interconnecting electrode terminals of a plurality of unit battery cells according to an appropriate amount of power, and a high-power rechargeable battery is realized.

[0006] The battery module can be constructed in a block design or in a modular design. In the block design, each battery is coupled to a common current collector structure and a common battery management system, and its units are arranged in a housing. In the modular design, multiple battery cells are connected to form a sub-module, and several sub-modules are connected to form a battery module. In automotive applications, the battery system is typically composed of multiple battery modules connected in series to provide the desired voltage. The battery module may include a sub-module having a plurality of stacked battery cells, and each stack includes parallel-connected cells (XpYs) connected in series or series-connected cells (XsYp) connected in parallel.

[0007] A battery pack is a group of any number of (usually identical) battery modules. The battery modules can be configured in series, parallel, or a mixture of series and parallel to provide the desired voltage, capacity, or power density. The components of a battery pack include the individual battery modules and interconnects that provide electrical conductivity between the battery modules.

[0008] The battery system also includes a battery management system (BMS), which is any electronic system that manages rechargeable batteries, battery modules, and battery packs, such as by protecting the battery from operating outside its safe operating range, monitoring the battery status, calculating secondary data, reporting the data, controlling the battery's environment, authenticating the battery, and / or balancing the battery. For example, the BMS can monitor the battery status represented by voltage (such as the total voltage of the battery pack or battery module, the voltage of each cell), temperature (such as the average temperature of the battery pack or battery module, the coolant input temperature, the coolant output temperature, or the temperature of each cell), coolant flow (such as flow rate, coolant pressure), and current.

[0009] Based on the above items, the BMS can calculate values ​​such as minimum and maximum cell voltages, state of charge (SOC) or depth of discharge (DOD) to indicate the battery's charge level, state of health (SOH; various definitions measure the percentage of a battery's remaining capacity relative to its original capacity), state of power (SOP; the amount of power available over a defined time interval given current power usage, temperature, and other conditions), state of safety (SOS), maximum charge current as charge current limit (CCL), maximum discharge current as discharge current limit (DCL), and the internal impedance of the cell (used to determine the open circuit voltage).

[0010] The BMS can be centralized, with a single controller connected to the battery cells through a large number of wires. The BMS can also be distributed with a BMS board installed at each cell and only a single communication cable between the battery and the controller. Or the BMS can be a modular construction including several controllers, each handling a corresponding number of cells, with communication between the controllers. Centralized BMS are usually the most economical, the least scalable, and suffer from a large number of wires. Distributed BMS are usually the most expensive, the simplest to install, and provide the cleanest components. Modular BMS provides a compromise between the features and problems of the other two topologies.

[0011] The BMS can protect the battery pack from operating outside its safe operating range. Operation outside the safe operating range can be indicated if there is overcurrent, overvoltage (overvoltage during charging), overtemperature, undertemperature, overvoltage, and ground fault or leakage current detection. The BMS can disable operation outside the safe operating range of the battery by including an internal switch (such as a relay or solid-state device) that disconnects if the battery operates outside its safe operating range, by requesting the device to which the battery is connected to reduce or even terminate the use of the battery, and by actively controlling the environment (such as by a heater, fan, air conditioning, or liquid cooling).

[0012] In order to meet the dynamic power usage of various electrical consumers connected to the battery system, static control of battery power output and charging is not enough. Therefore, a stable information exchange between the battery system and the controller of the electrical consumer is appropriate. The information includes the actual state of charge (SOC), potential electrical performance, charging capacity and / or internal resistance of the battery system and the actual or predicted power usage or surplus of the electrical consumer. The battery system may include a battery management system (BMS) for obtaining and processing such information at the system level, and also includes a plurality of battery module managers (BMMs) that are part of the battery module of the system and obtain and process relevant information at the module level. For example, the BMS typically measures the system voltage, the system current, the local temperature at different locations within the system housing, and the insulation resistance between the charged components and the system housing. The BMM can measure the individual cell voltages and cell temperatures of the battery cells in the battery module.

[0013] Therefore, a BMS / BMM is provided for managing a battery pack, such as by protecting the battery from operating outside a safe operating range, monitoring the status of the battery, calculating secondary data, reporting secondary data, controlling the environment of the battery, authenticating the battery and / or balancing the battery.

[0014] If an abnormal operating state exists, the battery pack can be disconnected from the load connected to the terminals of the battery pack. The battery system also includes a battery disconnect unit (BDU) electrically connected between the battery module and the battery system terminals. Therefore, the BDU is the main interface between the battery pack and the electrical system of the vehicle. The BDU includes an electromechanical switch that opens or closes the high current path between the battery pack and the electrical system. The BDU provides feedback such as voltage and current measurements to a battery control unit (BCU) accompanying the battery module. The BCU controls switches in the BDU using a low current path based on feedback received from the BDU. The main functions of the BDU may include controlling the current flow between the battery pack and the electrical system and current sensing. The BDU may also manage additional functions such as external charging and pre-charging.

[0015] A secondary battery cell, such as a lithium-ion battery cell, comprises two electrodes in an electrolyte solution. The electrodes are separated from each other by a separator made of an electrically insulating material (the so-called "dielectric"), which is however not very sensitive to the flow of ions (e.g., Li in a lithium-ion battery). + ions) to allow these ions to move freely between these electrodes. However, if there is damage to the diaphragm (for example, damage caused by mechanical damage from mechanical impact to the battery cell or damage caused by overloading of the battery cell), the material of the diaphragm may become ionized. Typically, after a corresponding period of time in the diaphragm, a channel is formed through the diaphragm after the conductive plasma is generated from the insulator material by heating and ionization. This situation is called "dielectric breakdown". In some cases, the dielectric breakdown may then continue to burn as an arc, resulting in an arc fault of the affected battery cell.

[0016] Typically, automotive battery systems include voltage sources with hazardous voltage levels. Due to the nature of the application, dielectric breakdown caused by misuse or accident may occur, which may lead to fire or explosion inside the battery system. For example, dielectric breakdown or ionization inside the battery system may cause a short circuit or arc discharge. However, arc discharge may take several seconds to take effect before it causes damage.

[0017] A method and a battery system are needed that allow for rapid detection of arc discharge within a battery module. In addition, a method and a battery system are needed that allow for disconnecting a battery module from a load after arc discharge within the battery module is detected. In addition, a vehicle equipped with one of the above battery systems is needed to improve safety in use.

[0018] One aspect of the present disclosure provides a method and a battery system that allow rapid detection of the occurrence of arc discharge in a battery module. In addition, one aspect of the present disclosure proposes a method and a battery system that allow disconnecting a battery module from a load after detecting an arc discharge in a battery module. In addition, one aspect of the present disclosure provides a vehicle equipped with one of the above battery systems to improve safety of use. Summary of the invention

[0019] The present disclosure is limited by the appended claims. The following description is subject to such limitations. Any disclosure outside the scope of the claims is intended for illustration and comparison purposes only.

[0020] The present disclosure describes a method and battery system that allows for the detection of arc discharge potentials within a battery module before any dangerous conditions occur. The detection can be accomplished by using existing measurements with additional signal conditioning circuitry configured to analyze the spectrum of these measurements or, for example, a signal generated based on these measurements.

[0021] Further aspects of the disclosure can be derived from the dependent claims or the following description.

[0022] One aspect of the methods and battery systems presented in the present disclosure is the ability to quickly detect undesirable developing ionization within a battery prior to a catastrophic short circuit or arc discharge. For example, ionization occurring within a battery module (e.g., in at least one of the battery cells of the battery module) has been identified during its initial stages, allowing the load to be electrically disconnected from the affected battery module before the battery module itself and / or a connected load is damaged by further ongoing ionization processes within the battery module. Ionization and increased conductive paths can be detected by implementing a signal conditioning circuit that analyzes the frequency spectrum of a suitable operating state of the battery module (such as current, voltage, or both).

[0023] According to one or more embodiments, a method for detecting dielectric breakdown in a battery module is provided, the method comprising the following steps: measuring at least one operating state of the battery module; generating at least one operating signal corresponding to the at least one operating state; checking whether the at least one operating signal includes a pattern indicating a possible arc fault within the battery module; and generating a warning signal when it is detected that the at least one operating signal includes the pattern.

[0024] At least one operating state may include a current generated by or occurring in the battery module, wherein the step of generating at least one operating signal includes generating a current signal based on at least one operating state including the current, and wherein the step of checking whether at least one operating signal includes a pattern includes checking whether the current signal includes a pattern.

[0025] At least one operating state may include a voltage generated by the battery module or a potential difference within the battery module, wherein the step of generating at least one operating signal includes generating a voltage signal based on at least one operating state including the voltage or the potential difference, wherein the step of checking whether at least one operating signal includes a pattern includes checking whether the voltage signal includes a pattern.

[0026] The step of checking whether the at least one operation signal includes a pattern may include the steps of: generating a spectrum for the at least one operation signal including a current signal and / or a voltage signal; and comparing the spectrum with a reference spectrum.

[0027] The step of comparing the spectrum with a reference spectrum may include: for at least one frequency value in the reference spectrum, detecting whether the amplitude of the spectrum exceeds the amplitude of the reference spectrum, wherein the step of generating a warning signal is based on detecting that the amplitude of the spectrum exceeds the amplitude of the reference spectrum at at least one frequency value.

[0028] The step of generating a frequency spectrum may comprise performing a Fourier transform on at least a portion of the current signal and / or the voltage signal.

[0029] The method may further include the steps of: storing the amplitude of at least one operating signal for sample time points within the time window; and performing a fast Fourier transform based on the stored amplitude for the sample time points.

[0030] The step of checking whether at least one operating signal includes a pattern may include the following steps: inputting at least one operating signal into at least one bandpass filter; measuring the amplitude of the signal output from the bandpass filter; and comparing the amplitude of the signal output from the bandpass filter with a reference value, and wherein the warning signal is based on detecting that the amplitude exceeds the reference value.

[0031] The method also includes disconnecting the battery module from the load in response to the warning signal.

[0032] According to one or more embodiments, a battery system is provided, which includes: a battery module including at least one battery cell; a measuring device configured to measure at least one operating state of the battery module and generate at least one operating signal corresponding to the at least one operating state; and a control unit configured to receive at least one operating signal from the measuring device, check whether the at least one operating signal includes a pattern indicating that an arc fault has occurred in the battery module, and generate a warning signal when it is detected that the at least one operating signal includes the pattern.

[0033] At least one operating state may include a current generated by or occurring in the battery module, wherein the measuring device includes a current sensor, the current sensor is configured to measure the current and is configured to generate a current signal corresponding to the current corresponding to at least one operating signal, and wherein the control unit is configured to check whether the current signal includes a pattern.

[0034] At least one operating state may include a voltage generated by the battery module or a potential difference inside the battery module, wherein the measuring device includes a voltage sensor, the voltage sensor is configured to measure the voltage and is configured to generate a voltage signal corresponding to the voltage corresponding to the at least one operating signal, and wherein the control unit is configured to check whether the voltage signal includes a pattern.

[0035] The control unit may be configured to generate a frequency spectrum of at least one operation signal corresponding to the current signal or the voltage signal, and compare the frequency spectrum with a reference frequency spectrum.

[0036] The battery system may also include: a first terminal, connected to at least one battery cell via a first electrical circuit; a second terminal, connected to at least one battery cell via a second electrical circuit; a first switch, configured to interrupt the first electrical circuit upon receiving a first interrupt signal; and a second switch, configured to interrupt the second electrical circuit upon receiving a second interrupt signal, wherein the control unit is configured to send the first interrupt signal and / or send the second interrupt signal based on the warning signal.

[0037] According to one or more embodiments, a vehicle including the battery system is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various aspects will become apparent to those skilled in the art by describing the embodiments in detail with reference to the accompanying drawings.

[0039] Figure 1 It is a schematic three-dimensional diagram of a battery module.

[0040] Figure 2 is a block diagram schematically illustrating aspects of the operation of one or more embodiments of the method.

[0041] Figure 3 Current measurements during normal operation and during arcing are schematically shown.

[0042] Figure 4 Schematic diagram showing the extraction of the amplitude value of the current during arc discharge in the time domain (A) and the frequency domain (B).

[0043] Figure 5A , Figure 5B and Figure 5CSeveral different embodiments of a battery system according to the present disclosure are schematically illustrated.

[0044] Figure 6 Schematically illustrates spectral analysis of an input signal using an analog circuit. DETAILED DESCRIPTION

[0045] Reference will now be made in detail to embodiments, examples of which are shown in the accompanying drawings. Aspects of the embodiments and methods for implementing the same will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same elements, and redundant descriptions are omitted. However, the present disclosure may be implemented in various different forms and should not be construed as being limited to the embodiments shown herein. On the contrary, these embodiments are provided as examples so that the present disclosure will be thorough and complete, and will fully convey aspects of the present disclosure to those skilled in the art.

[0046] Therefore, processes, elements, and techniques that are not considered necessary for one of ordinary skill in the art to fully understand aspects of the present disclosure may not be described.In the drawings, relative sizes of elements, layers, and regions may be exaggerated for clarity.

[0047] As used herein, the term "and / or" includes any and all combinations of one or more of the relevant listed items. In addition, when describing the embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure." In the following description of the embodiments of the present disclosure, unless the context clearly indicates otherwise, a term in the singular form may include a plural form.

[0048] It will be understood that, although the terms "first" and "second" are used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, the first element can be named as the second element, and similarly, the second element can be named as the first element. As used herein, the term "and / or" includes any combination and all combinations of one or more of the relevant listed items. Expressions such as "at least one (kind / person) of..." modify the entire column of elements when following a column of elements, without modifying the individual elements in the column.

[0049] As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than as terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that one of ordinary skill in the art would recognize. In addition, if the term "substantially" is used in combination with a feature that can be expressed using a numerical value, the term "substantially" means a range of + / - 5% of a value centered on that value.

[0050] It will also be understood that the terms "comprises," "comprising" or variations thereof refer to properties, regions, fixed numbers, steps, processes, elements, components and combinations thereof, but do not exclude other properties, regions, fixed numbers, steps, processes, elements, components and combinations thereof.

[0051] Here, the terms "upper" and "lower" are defined according to the Z axis. For example, the upper cover is positioned at the upper part of the Z axis, and the lower cover is positioned at the lower part of the Z axis. In the accompanying drawings, the size of the elements may be exaggerated for clarity. For example, in the accompanying drawings, the size or thickness of each element may be arbitrarily shown for the purpose of illustration, and thus the embodiments of the present disclosure should not be construed as being limited thereto.

[0052] In the following description of the embodiments of the present disclosure, terms in the singular form may include plural forms unless the context clearly indicates otherwise.

[0053] The electronic or electrical devices and / or any other related devices or components according to the embodiments of the present disclosure described herein can be implemented using any suitable hardware, firmware (e.g., application specific integrated circuits), software, or a combination of software, firmware, and hardware. In addition, the various components of these devices can be implemented on flexible printed circuit films, tape carrier packages (TCPs), printed circuit boards (PCBs), or formed on a substrate. The electrical connections or interconnections described herein can be implemented by wires or conductive elements on, for example, PCBs or another circuit carrier. The conductive elements can be metallized (e.g., surface metallization) and / or include pins, and / or can include conductive polymers or conductive ceramics. Additional electrical energy can be transmitted via a wireless connection (e.g., using electromagnetic radiation and / or light).

[0054] In addition, the various components of these devices can be processes or threads running on one or more processors in one or more computing devices, which execute computer program instructions and interact with other system components for performing the various functions described herein. Computer program instructions are stored in a memory that can be implemented in a computing device using a standard memory device (such as a random access memory (RAM) as an example). Computer program instructions can also be stored in other non-transitory computer-readable media (such as a CD-ROM, a flash drive, etc. as an example).

[0055] Furthermore, those skilled in the art will recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of the embodiments of the present disclosure.

[0056] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an idealized or overly formal sense, unless explicitly defined as such herein.

[0057] Figure 1 is a schematic three-dimensional diagram of a battery module. Figure 1 One or more embodiments of the conventional battery module 100 include a direction (e.g., referring to Figure 1 A plurality of battery cells 110 are arranged in the X direction of the battery module 100. A heat exchange member 170 may also be provided adjacent to the bottom surface of the plurality of battery cells 110. In addition, a pair of end plates 118 are provided to face the wide surface of the battery cells 110 at the outside of the battery cells 110, and a connecting plate 119 is configured to connect the pair of end plates 118 to each other, thereby also fixing the plurality of battery cells 110 together. The fastening portions 118a on both sides of the battery module 100 are fastened to the support plate 131 by bolts 140. The support plate 131 is a part of the housing 130.

[0058] In one or more embodiments, each battery cell 110 is a roughly prismatic or roughly cubic monomer, and the wide flat surfaces of the monomers are stacked together to form a battery module. In addition, each battery cell 110 includes a battery case configured to accommodate an electrode assembly and an electrolyte. The battery case is hermetically sealed by a cap assembly 114. The cap assembly 114 is provided with a positive electrode terminal 111 and a negative electrode terminal 112 having different polarities and a vent 113.

[0059] The positive electrode T1 of the first battery cell (the first battery cell when viewed along the X-axis) forms the positive terminal of the battery cell stack. Correspondingly, the negative electrode T2 of the last battery cell (the last battery cell when viewed along the X-axis) forms the negative terminal of the battery cell stack. Since the illustrated battery module 100 includes only a single battery cell stack, the terminal T1 simultaneously forms the positive electrode of the entire battery module 100, and the terminal T2 simultaneously forms the negative electrode of the entire battery module 100.

[0060] The exhaust port 113 is a safety device of the battery cell 110, and the exhaust port 113 serves as a passage through which the gas generated in the battery cell 110 is discharged to the outside of the battery cell 110. The positive electrode terminal 111 and the negative electrode terminal 112 of the adjacent battery cells 110 are electrically connected by the bus bar 115, and the bus bar 115 may be fixed by a nut 116 or the like. In one or more embodiments, the battery module 100 may be used as a power supply unit by electrically connecting a plurality of battery cells 110 as a bundle.

[0061] The battery cell 110 generates a large amount of heat while charging / discharging. The generated heat accumulates in the battery cell 110, thereby accelerating the degradation of the battery cell 110. In one or more embodiments, the battery module 100 further includes a heat exchange member 170, which is disposed adjacent to the bottom surface of the battery cell 110 to cool the battery cell 110. In one or more embodiments, an elastic member 120 made of rubber or other elastic material may be disposed between the support plate 131 and the heat exchange member 170.

[0062] Figure 2 1 is a block diagram schematically illustrating operational aspects of one or more embodiments of a method for detecting the occurrence of dielectric breakdown in a battery module according to the present disclosure and a corresponding battery system. For example, the figure shows a battery system 1 including a battery module 10 and a control unit 20 according to the present disclosure. The battery module 10 includes a plurality of battery cells. The battery cells may be arranged into at least one battery cell stack. For example, the battery module 10 may correspond to Figure 1 However, it is understood that other internal arrangements (eg, configurations) of battery cells may also be used within the interior of a battery module 10 that includes a plurality of battery cell stacks.

[0063] In with Figure 2 In one or more embodiments of the corresponding battery system 1, the battery system 1 is configured to monitor two different operating conditions of the battery module 10, such as the current generated by the battery module 10 and the voltage generated by the battery module 10. In one or more embodiments, a measuring device with corresponding sensors can be implemented as the battery system 1, each sensor being configured to measure one of the operating conditions to be measured. Because the current and voltage generated by the battery module 10 are to be measured, the measuring device of the battery system 1 includes a current sensor 41 and a voltage sensor 42 (for example, see Figure 5A , Figure 5B and Figure 5C ). For example, if the battery module 10 corresponds to Figure 1 The battery module 100 shown in FIG. 1 , the current sensor 41 can be connected to Figure 11 and 10. The battery cell stack depicted in FIG. 1 is arranged in series (e.g., electrically connected to the first terminal T1 of the battery cell stack depicted or electrically connected to the second terminal T2 of the battery cell stack depicted). In addition, the voltage sensor 42 can be arranged in parallel with the battery cell stack depicted (e.g., electrically connected to both the first terminal T1 and the second terminal T2). However, for example, if the battery module 10 is internally connected to Figure 1 If the battery module 100 is assembled differently, the current sensor 41 and / or the voltage sensor 42 may be arranged in the battery module 10 in other ways. This will be described below with reference to Figure 5A , Figure 5B and Figure 5C Explain in more detail.

[0064] Each of the sensors generates a signal (operation signal) corresponding to the operating state of the battery module 10 measured by the sensor. Figure 2 In the example of, the current sensor 41 generates an operation signal corresponding to the measured current (the operation signal is referred to as the current signal hereinafter), and the voltage sensor 42 generates an operation signal corresponding to the measured voltage (the latter operation signal is referred to as the voltage signal hereinafter). In addition, the control unit 20 is configured to receive each of the operation signals generated by the sensors of the measuring device. In one or more embodiments, the control unit 20 is configured to receive the current signal S1 from the current sensor 41 and the voltage signal S2 from the voltage sensor 42.

[0065] Furthermore, the control unit 20 is configured to evaluate the received operating signals, for example, to detect whether at least one of the operating signals exhibits a pattern indicating the occurrence of an arc fault within the battery module 10 (for example, in at least one of the battery cells included in the battery module 10). Figure 3 and Figure 4 The above-described evaluation of the received operating signals and detection of patterns indicative of a possible arc fault is described in more detail.

[0066] An automotive battery system typically supplies or receives a continuously varying current. However, since the electrically connected systems (loads) each have a corresponding inductance, the current usage and / or current supply typically does not change abruptly (e.g., in a discontinuous manner with respect to time), but typically only changes within a corresponding window. The change in current intensity (amperage) with respect to time typically does not exceed a defined derivative level, or equivalently, using the formula, when the current intensity is expressed as a function of time t I(t), it maintains |dI(t) / dt|≤c, where c>0 and is a known constant.

[0067] This is Figure 3 As schematically shown in (A), Figure 3(A) shows a curve of the current intensity (the ordinate of the graph) provided by the battery module as a function of time t (the abscissa of the graph). As indicated in the figure, the current can be measured in amperes (A) and the time can be given in seconds (s), noting that the figure is only illustrative. For example, the value of the current intensity at time point t0 is I0. At time point t0, the use of current suitable for the load connected to the battery module can be increased. The current provided by the battery module increases until it is at time point t max The maximum value I max , where I max It can correspond to the current supply suitable for the load.

[0068] However, it can be seen from the figure that the current supplied by the battery module does not increase continuously (for example, the function I(t) is s Instead, starting at t0, the current first increases only slightly, then the increase occurs more rapidly until the increase in current is at time t s reaches its maximum value. At time t s After that, the current increases at t max Before reaching its maximum value at time t max After that, the current intensity remains approximately constant (see the area around time point t1). Figure 3 As can be seen from (A), the change (absolute value) of the current intensity I(t) |dI(t) / dt| (ie, the slope of the curve depicted in the figure) does not exceed the time point t s The slope value at .

[0069] Although Figure 3 (A) shows a curve of current with respect to time when the battery module is in a normal operating state, but when an arc fault occurs in at least one battery cell of the battery module, the curve of the current will be Figure 3 The curve shown in (A) is significantly different. Figure 3 As schematically shown in (B), Figure 3 (B) shows the Figure 3 (A) is roughly the same as (B), but the difference is that an arc fault event occurs in the battery module. If there is an arc discharge, the current intensity changes very quickly in a short period of time. This is Figure 3 In (B) (at time point t in With t fin The behavior of the graph shown in the region ARC between φ(t) and φ(t) is schematically shown, where the function I(t) changes very quickly between various quite different values ​​of the current intensity (as in the example Figure 3In the case of arc discharge, the derivative of the current intensity with respect to time far exceeds the maximum value of the derivative that can be achieved if the battery module is in normal operation as explained above. In one or more embodiments, for the corresponding time t, during the arc discharge, an absolute derivative value |dI(t) / dt|>c (where c>0) will appear, which becomes the maximum limit of the absolute value of the derivative of the current intensity with respect to time explained above.

[0070] However, as mentioned above Figure 3 As indicated by the region ARC in (B), if arcing is present, not only a single sudden change in current intensity is experienced, but also very rapid changes between higher and lower values ​​of current intensity. In one or more embodiments, the arcing current is uncontrolled and occurs without (approximately) linear increments. Therefore, when observing the spectral representation of the current intensity as a function of time, as Figure 3 As shown in (B), there will be frequencies with significant amplitudes that correspond to rapid changes in current caused by arc discharge as described above. For example, frequencies indicative of arc discharge may occur in corresponding frequencies around 100kHz. In one or more embodiments, in the event of an arc fault in the battery module, the frequency representation of the current intensity will exhibit very high amplitudes for frequencies caused by or associated with arc discharge. In one or more embodiments, arc discharge events can be detected by filtering noise, adding a data window-based search, and observing corresponding patterns in the spectrum.

[0071] Figure 4 (A) is related to Figure 3 (B) is a similar diagram. For example, the current intensity supplied by the battery module (the ordinate of the diagram) is schematically shown as a function of time (the abscissa of the diagram). The actual current of the load connected to the battery module is given by Figure 4 The straight horizontal lines of the curves depicted in (A) (corresponding current intensities of I1 and I2, respectively) indicate that at the starting time point t0, the load of the battery module may be caused by a corresponding device electrically connected to the battery, wherein the device is supplied with a constant current.

[0072] Then, at time t s At this point in time, another device can be switched on so that the load usage is s becomes relatively fast at time t. s The step of the depicted curve at , although the step can show a flat shape with a maximum derivative not exceeding the corresponding boundary value, as previously shown in Figure 3 At time point t sThereafter, high frequency changes in the curve of the current intensity are experienced (indicated in the figure by the area ARCT), which may indicate the occurrence of an arc fault event in the battery module.

[0073] Figure 4 (B) schematically shows the Figure 4 Spectral representation of the current intensity shown in (A). Figure 4 The function in (B) can be obtained by Figure 4 The Fourier transform (fast Fourier transform) of the function shown in (A) is obtained. Figure 4 (A) is expressed as a function of I(t) with time t (i.e., with the "time domain"), but the current intensity is Figure 4 (B) as a function of frequency f (e.g., in the “frequency domain”) Because in Figure 4 (B) shows only the amplitude (absolute value) of the frequency f. therefore Figure 4 (B) may not be completely equivalent to Figure 4 (A), because in Figure 4 The phase is omitted in (B). Figure 4 (A) and Figure 4 (B) is merely illustrative, and for example, Figure 4 The function shown in (B) It may not be Figure 4 The exact spectrum representation of the function I(t) of (A).

[0074] based on Figure 4 The information provided in (A) generates Figure 4 The spectrum analysis of (B) may have been performed using t win With t wfin The time window between (including time point t s ) is executed. Since at time point t s The current intensity at the point shows a sudden step-like increase in the time domain (see Figure 4 (A)), the spectrum shows the minimum amplitude corresponding to all frequencies f in the frequency range shown. For example, as described above, with a flat step of current intensity in the time domain, this "background" may not be constant throughout the frequency domain, but may decrease slightly as the frequency f increases.

[0075] Furthermore, the spectrum shown represents the amplitude as a function of frequency f Other shapes are possible. However, during normal operation of the battery module, the amplitude The maximum value corresponding to each Define, the maximum value can be frequency-dependent (e.g., can be given as a function of frequency f). Figure 4 In the example of (B), it can be set to However, in general, the limit of the maximum value of the amplitude during normal operation of the battery module may depend on the frequency f (for example, there may be a limit function Such that for all frequencies or at least for each frequency f within the relevant frequency range, ) was established.

[0076] However, as can be seen from FIG. 4(B), for Figure 4 This is not the case for the function shown in (B) of in With f fin The frequency spectrum shown as a function of frequency f in the frequency range between Amplitude shows very intensive and drastic changes (see the region indicated as ARCF in FIG. 4(B) ), which can be considered similar to the behavior of the current intensity I(t) in the region ARCT when viewed in the time domain (see Figure 4 For example, in the region ARCF, there are amplitudes much larger than the "background" amplitude in this example. The frequency of This no longer holds true in the example shown, since there is an amplitude In one or more embodiments, it is checked by means of a frequency spectrum representation relative to the current intensity whether at least some of the frequency values ​​f caused by or associated with the arc discharge violate the relation Or equivalently, does the relation hold for at least some frequency values ​​f caused by or associated with the arc discharge? Can be easily detected Figure 4 Noise in the ARCT region of (A) (showing current intensity relative to time domain).

[0077] However, due to the natural or usual variations in frequency that may occur in the absence of an arc fault event, the relationship To detect arc faults, the detection may be an overly sensitive check, resulting in an increased likelihood of false positive detections of arc faults and / or false alarms. In one or more other embodiments, to avoid oversensitivity, a threshold amplitude (e.g., a predetermined threshold amplitude) may also be frequency-dependent (e.g., may be given as a function of frequency f). To check the relationship is violated, where, for all frequencies f within the relevant frequency range, At the same time, is selected to be less than a peak value (e.g., a typical or expected peak value) in the amplitude of a spectral representation of the current intensity during an arc fault event. Figure 4 (B) Example of a (constant) threshold amplitude Schematically shown, where in, Indicates the current intensity if an arc fault event occurs The spectrum represents the peak amplitudes.

[0078] In one or more embodiments, one of the above checks may be implemented in an embodiment of a method for detecting the occurrence of dielectric breakdown in a battery module (e.g., using the symbols defined above, checking the relationship Whether it has been violated, or check the relationship In such an embodiment, at least one of the measured operating states of the battery module is a current measured by a current sensor 41 within the battery module, and the operating signal is a current signal generated by the current sensor 41, or at least a signal equivalent to the current signal (e.g., the original current signal multiplied by a corresponding constant factor for scaling, etc.).

[0079] In one or more embodiments, other operating states of the battery module may also be measured and checked in a similar manner in one or more other embodiments of the method according to the present disclosure. For example, in one or more other embodiments of the present disclosure, a measured voltage may be used instead of a measured current. In one or more embodiments, voltage and current are measured in the battery module, and two operating states of the battery module (e.g., measured voltage and measured current) are monitored and checked during operation of the battery module.

[0080] The monitoring of the operating state may be performed permanently (e.g., continuously for each time t in the time domain). In one or more other embodiments, the check is repeatedly performed only for discrete points in the time domain. It may be appropriate to measure the monitored operating state (such as current and / or voltage) of the battery module for a corresponding time window of length (e.g., a predetermined length) to convert the measurement into a spectral representation.

[0081] In order to be able to perform the above-mentioned check on the operating signal (e.g., the current and / or voltage measured in the battery module), the control unit can be configured so that a transformation of the time-dependent input signal based on the measured operating state into a spectral representation can be performed. In an embodiment, this can be done digitally (e.g., by storing the value of the input operating signal (such as the current signal and / or the voltage signal) for a duration (e.g., a predefined duration) ΔT) and can be done by subsequently using the stored value as an input to a Fourier transform performed by a CPU or microcontroller. In one or more other embodiments, as will be referred to below Figure 6 As described in more detail, the spectral representation of the input signal may be performed by analog techniques such as filter banks.

[0082] Figure 5A , Figure 5B and Figure 5C Several different embodiments of the battery system according to the present disclosure are schematically shown. For example, Figure 5A The battery system 1a is shown to include a battery module 10a having three battery cell stacks 31, 32, 33. Each of the battery cell stacks 31, 32, 33 includes a plurality of battery cells 110. Figure 5A In the example of , three battery cell stacks 31, 32, 33 are electrically connected in parallel. The current sensor 41 is connected in series to the battery module 10a (e.g., connected in series to the entirety of the three battery cell stacks 31, 32, 33 connected in parallel). In addition, the voltage sensor 42 is connected in parallel to the battery module 10a. In one or more embodiments, if at least one of the battery cells 110 included in the battery module 10a (e.g., in one of the battery cell stacks 31, 32, 33) undergoes developing ionization in combination with an arc discharge, the effects of the above-mentioned high-frequency changes in current and voltage are superimposed on the current and voltage generated by the complete assembly of the three battery cell stacks 31, 32, 33, which can then be measured by both the current sensor 41 and the voltage sensor 42.

[0083] As a result of these measurements, an operating signal is then transmitted to the control unit CU of the battery system 1a. For example, a current signal is transmitted to the control unit CU via the first signal line 41a, and a voltage signal is transmitted to the control unit CU via the second signal line 42a. The control unit CU then performs the above-mentioned Figure 3 and Figure 4The described method evaluates these operating signals. For example, the control unit CU checks the incoming operating signals for patterns that may indicate arc discharge inside the battery module 10a. When such a pattern is detected, the control unit CU generates a warning signal, which, in the example shown, is used to operate the switch 50 to disconnect the battery module 10a from the load, which may be connected to the battery module 10a via the terminals T1 and T2. For example, the warning signal may be transmitted to the switch 50 via the warning signal line 50a. In one or more other embodiments, another switch may be provided between the battery module 10a and the first terminal T1, and the other switch is operated by the control unit CU similarly to the switch 50 shown. Then, when an arc fault inside the battery module 10a is detected, the two terminals T1 and T2 of the battery module 10a will be disconnected.

[0084] The battery system 1b according to one or more other embodiments of the present disclosure corresponds to Figure 5B As in Figure 5A In the example of FIG. 1 , the battery system 1 b includes a battery module 10 b equipped with three battery cell stacks 31 , 32 , 33 connected in parallel to each other. However, in one or more embodiments, Figure 5A Compared to the example of FIG. 1 , the operating state for checking the arc fault occurring inside the battery module 10 b is measured differently. For example, in the example shown, the current intensity and the voltage are measured separately for each of the battery cell stacks 31, 32, 33. For example, the first current sensor 411 is connected in series with the first battery cell stack 31, and correspondingly, the second current sensor 412 and the third current sensor 413 are connected in series with the second battery cell stack 32 and the third battery cell stack 33, respectively. In addition, the voltage sensor 42 is installed in parallel with the entire battery cell stack 31, 32, 33, which is different from FIG. Figure 5A The arrangement of the voltage sensor 42 in the example of FIG.

[0085] In one or more embodiments, Figure 5B In the example, the current generated by each of the battery cell stacks 31, 32, 33 can be measured individually so that if an arc fault occurs inside the battery module 10a, it can be detected which of the battery cell stacks 31, 32, 33 contains the battery cell affected by the arc fault.

[0086] Each of the current sensors 411, 412, 413 and the voltage sensor 42 is connected to the control unit via a corresponding signal line. Figure 5B The control unit and the signal lines are not shown. Again, the control unit is configured as described above. Figure 3 and Figure 4The method described herein evaluates the operating signal and generates a warning signal, which in the example shown is used to operate the switch 50 to disconnect the battery module 10b from a load that can be connected to the battery module 10b via the terminals T1 and T2. Again, in an embodiment, a second switch that operates in a similar manner to the switch 50 shown can be implemented to disconnect the battery module 10b from the first terminal T1.

[0087] also, Figure 5C Another possibility of arranging the operating sensor inside the battery module is schematically shown. For example, one or more other embodiments of the battery system 1c include a battery module 10c having only a single battery cell stack. For example, the battery module 10c may correspond to Figure 1 The battery module 100 shown in FIG. 1 is a battery module 100 shown in FIG. 1 . In the example, the current sensor 41 is not connected in series with the battery module 10c, but is arranged inside the battery cell stack of the battery module 10c between two adjacent battery cells 110a, 110b. The signal generated by the current sensor 41 is transmitted to the control unit CU, which is configured to operate the switch 50 to disconnect the battery module 10c from the load that can be connected to the battery module 10c via the terminals T1, T2 when an arc fault inside the battery module 10c is detected.

[0088] Figure 6 Schematic showing how to use analog circuits to perform input signal S in Spectrum analysis of the input signal S in It may be one of the operating signals generated by the measuring device / measuring sensor according to the embodiment of the battery system of the present disclosure. Here, the input signal S in is input to a filter bank FB including a plurality of bandpass filters BP1, BP2, ..., BPn. In the depicted embodiment of the analog circuit, the bandpass ranges of the bandpass filters BP1, BP2, ..., BPn may be separated in pairs. However, in an embodiment, the bandpass ranges of the bandpass filters BP1, BP2, ..., BPn may partially overlap. Then, the first bandpass filter BP1 passes frequencies within a corresponding range near a first frequency, the second bandpass filter BP2 passes frequencies within a corresponding range near a second frequency different from the first frequency, and so on. Subsequently, the amplitude of the signal that has passed through the bandpass filters BP1, BP2, ..., BPn is measured by the respective current sensors 411, 412, ..., 41n. In this way, the incoming input signal S in The spectrum of Figure 6 The circuit depicted in is generated. Figure 6 The circuit may be used in embodiments of a battery system according to the present disclosure to generate a spectral representation of an operating signal.

[0089] Description of some reference symbols

[0090] 1: Battery system 1a, 1b, 1c: Battery system

[0091] 10: Battery module 10a, 10b, 10c: Battery module

[0092] 20: Control unit 31, 32, 33: Battery cell stack

[0093] 41: Current sensor 42: Voltage sensor

[0094] 50: switch 100: battery module

[0095] 110: Battery cell 111: Positive electrode

[0096] 112: Negative electrode 113: Exhaust port

[0097] 114: Cover assembly 115: Bus bar

[0098] 116: Nut 118: End plate

[0099] 118a: Fastening part 130: Housing

[0100] 131: Support plate 140: Bolt 170: heat exchange member 411, 412, 413, 41n: current sensor ARC, ARCT: Area of ​​current intensity as a function of time domain

[0101] ARCF: Area of ​​current intensity as a function of frequency domain

[0102] BP1, BP2, BPn: Bandpass filter CU: Control unit

[0103] f: frequency f in ,ff in : Frequency value

[0104] FB: Filter Bank

[0105] I(t): current intensity as a function of time domain

[0106] I0, I1, I2, I max : The value of the current intensity

[0107] The amplitude of the current intensity as a function of the frequency domain (in spectral representation)

[0108] Amplitude of current intensity

[0109] S1: current signal S2: voltage signal

[0110] S in : Input signal t: time

[0111] t0、t s , t1: time point t win ,t wfin : Time point

[0112] T1, T2: Terminals X, Y, Z: Axes of the Cartesian coordinate system.

Claims

1. A method for detecting dielectric breakdown in a battery module, the method comprising the following steps: measuring at least one operating state of the battery module; generating at least one operation signal corresponding to the at least one operation state respectively; checking whether the at least one operating signal includes a pattern indicative of a possible arc fault within the battery module; as well as A warning signal is generated upon detecting that the at least one operation signal includes the pattern.

2. The method according to claim 1, wherein: The at least one operating state includes a current flow generated by or occurring in the battery module, wherein the step of generating the at least one operating signal comprises generating a current signal based on the at least one operating state including the current, and The step of checking whether the at least one operating signal includes the pattern includes checking whether the current signal includes the pattern.

3. The method according to claim 1, wherein: The at least one operating state includes a voltage generated by the battery module or a potential difference within the battery module, wherein the step of generating the at least one operating signal comprises generating a voltage signal based on the at least one operating state comprising the voltage or the potential difference, and The step of checking whether the at least one operating signal includes the pattern includes checking whether the voltage signal includes the pattern.

4. The method according to claim 3, wherein: The step of checking whether the at least one operating signal comprises the pattern comprises the following steps: generating a frequency spectrum for said at least one operating signal comprising a current signal and / or said voltage signal; and The spectrum is compared to a reference spectrum.

5. The method according to claim 4, wherein: The step of comparing the spectrum with the reference spectrum comprises: for at least one frequency value in the reference spectrum, detecting whether the amplitude of the spectrum exceeds the amplitude of the reference spectrum, and Therein, the step of generating the warning signal is based on detecting that the amplitude of the spectrum exceeds the amplitude of the reference spectrum at the at least one frequency value.

6. The method according to claim 4, wherein: The step of generating the frequency spectrum comprises performing a Fourier transform on at least a portion of the current signal and / or the voltage signal.

7. The method according to claim 6, further comprising the steps of: storing the amplitude of the at least one operating signal for sample time points within the time window; as well as A Fast Fourier Transform is performed based on the stored amplitudes for the sample time points.

8. The method according to claim 2, wherein: The step of checking whether the at least one operating signal comprises the pattern comprises the following steps: inputting the at least one operating signal to at least one bandpass filter; measuring the amplitude of a signal output from the bandpass filter; and comparing the amplitude of the signal output from the bandpass filter with a reference value, and The warning signal is based on detecting that the amplitude exceeds the reference value.

9. The method of claim 1, further comprising disconnecting the battery module from a load in response to the warning signal.

10. A battery system, comprising: A battery module, comprising at least one battery cell; a measuring device configured to measure at least one operating state of the battery module and generate at least one operating signal corresponding to the at least one operating state; as well as A control unit is configured to receive the at least one operation signal from the measuring device, check whether the at least one operation signal includes a pattern indicating that an arc fault has occurred in the battery module, and generate a warning signal when detecting that the at least one operation signal includes the pattern.

11. The battery system according to claim 10, wherein: The at least one operating state includes a current flow generated by or occurring in the battery module, wherein the measuring device comprises a current sensor configured to measure the current and to generate a current signal corresponding to the current corresponding to the at least one operation signal, and Wherein, the control unit is configured to check whether the current signal includes the pattern.

12. The battery system according to claim 10, wherein: The at least one operating state includes a voltage generated by the battery module or a potential difference within the battery module, wherein the measuring device comprises a voltage sensor configured to measure the voltage and to generate a voltage signal corresponding to the voltage corresponding to the at least one operating signal, and Wherein, the control unit is configured to check whether the voltage signal includes the pattern.

13. The battery system according to claim 12, wherein: The control unit is configured to generate a frequency spectrum of the at least one operation signal corresponding to the current signal or the voltage signal, and compare the frequency spectrum with a reference frequency spectrum.

14. The battery system according to claim 10, further comprising: a first terminal connected to the at least one battery cell via a first electrical line; a second terminal connected to the at least one battery cell via a second electrical line; a first switch configured to interrupt the first electrical circuit upon receiving a first interrupt signal; as well as a second switch configured to interrupt the second electrical line upon receiving a second interrupt signal, The control unit is configured to send the first interrupt signal and / or send the second interrupt signal based on the warning signal.

15. A vehicle comprising a battery system according to any one of claims 10 to 14.

Images