Battery system with improved cover plate and electric vehicle including same

Abstract

A battery system having an improved cover plate and an electric vehicle including the same are provided. A battery system for an electric vehicle includes: a plurality of battery cells, each battery cell having an exhaust side having an exhaust outlet for allowing an exhaust flow to exit the battery cell; a case accommodating the battery cells; a cover plate covering the battery cells on the exhaust side to protect the battery cells from exhaust products in the exhaust gas flow, the cover plate having exhaust openings respectively aligned with the exhaust outlets for allowing the exhaust gas flow to pass through the cover plate; a thermally insulating sealing layer between the cap plate and the exhaust side of the battery cell, the sealing layer extending around the exhaust outlet; and a mounting assembly that secures the cover plate to the housing such that the cover plate exerts a pressure on the sealing layer.

Description

Technical Field

[0001] Aspects of the disclosed embodiments relate to a battery system having an improved cover plate. Background Art

[0002] In recent years, vehicles for the transportation of goods and people using electricity as a power source have been developed. Such electric vehicles are cars driven by electric motors, using energy stored in rechargeable batteries. Electric vehicles can be powered only by batteries, or can be hybrid vehicles that are partially powered by, for example, gasoline generators or hydrogen fuel cells. In addition, hybrid vehicles can include a combination of electric motors and traditional internal combustion engines. 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 batteries, lighting batteries, 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 is designed to be repeatedly charged and discharged, while a primary battery is designed to provide only an irreversible conversion of chemical energy to electrical energy. Low-capacity rechargeable batteries can be used as power sources for small electronic devices such as mobile phones, laptops, and cameras, while high-capacity rechargeable batteries can be used as power sources for electric vehicles and hybrid vehicles, etc.

[0003] In general, a rechargeable battery includes: an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a housing for receiving (or accommodating) the electrode assembly, and an electrode terminal electrically connected to the electrode assembly. An electrolyte solution is injected into the housing to achieve charging and discharging of the battery through an electrochemical reaction between the positive electrode, the negative electrode, and the electrolyte solution. The shape of the housing, such as cylindrical or rectangular, depends on the intended use of the battery. Lithium-ion (and similar lithium polymer) batteries, which are widely known through their use in laptop computers and consumer electronics, dominate the latest developments in electric vehicles.

[0004] The rechargeable battery may be used as (or as part of) a battery module including a plurality of unit battery cells coupled in series and / or in parallel to each other to provide high energy density, particularly for motor drive of hybrid vehicles. For example, a battery module may be formed by interconnecting electrode terminals of a plurality of unit battery cells in an arrangement based on a desired amount of power, and provide a high-power rechargeable battery.

[0005] The battery module can be constructed in a block design or 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 together to form a sub-module, and several sub-modules are connected together to form a battery module. In automotive applications, the battery system typically includes a plurality of battery modules connected in series to provide the desired voltage. Among them, the battery module may include a sub-module having a plurality of stacked battery cells, and each stack includes cells connected in parallel to each other and then in series (XpYs) or cells connected in series to each other and then in parallel (XsYp).

[0006] A battery pack is a group of any number of battery modules. Typically, the battery modules in a battery pack are identical. The battery modules can be configured in series, parallel, or a mixture of the two (e.g., can be connected together in series, parallel, or a mixture of the two) to provide a desired voltage, capacity, and / or power density. The components of a battery pack include individual battery modules and interconnects that provide electrical conductivity between the battery modules.

[0007] In order to provide thermal control for the battery cells within the battery housing, a thermal management system can be used to effectively dissipate, release and / or dissipate the heat generated within the battery housing. If the heat dissipation, release and / or dissipation is not adequately performed, temperature deviations may occur between the individual battery cells, so that the at least one battery module may no longer generate the desired (or designed) amount of power. In addition, an increase in internal temperature can cause abnormal reactions in the battery cells. As a result, the charging and discharging performance of the rechargeable battery deteriorates, and the life of the rechargeable battery is shortened. Therefore, battery cell cooling for effectively dissipating, releasing and / or dissipating heat from the battery cells is important.

[0008] Exothermic decomposition of a cell assembly may lead to so-called thermal runaway. Thermal runaway is a self-accelerating chemical reaction inside a battery cell that generates a large amount of heat and exhaust gases until almost all available materials are exhausted. Exhausted materials (that is, exhaust products) may include hot and toxic exhaust gases and potentially conductive solid materials such as graphite powder and metal fragments. In rechargeable battery systems, thermal runaway is associated with strong exothermic reactions, which are accelerated by increased temperatures. These exothermic reactions include the combustion of combustible gas components within the battery pack housing. For example, when a battery cell is heated above a critical temperature (usually above about 150°C), the battery cell will turn into thermal runaway. The initial heating may be caused by a local fault (such as a battery cell with an internal short circuit, heating caused by a defective electrical contact, and / or a short circuit with an adjacent battery cell). During thermal runaway, a faulty battery cell (that is, a battery cell with a local fault) may reach a temperature of more than about 700°C. In addition, a large amount of hot gas is ejected from the inside of the faulty battery cell into the battery pack through the exhaust outlet in the cell housing. The main components of the exhaust gas are H2, CO2, CO, electrolyte vapor and other hydrocarbons. In addition, the exhaust gas is flammable and potentially toxic. The exhaust gas may also cause the gas pressure inside the battery pack to increase.

[0009] The venting concept of the related art of the battery is to allow the exhaust gas flow (including hot exhaust gas and particles exiting the battery cell) to expand into the battery housing and escape to the outside (e.g., to the environment of the battery housing) through the housing exhaust valve. The exhaust gas flow heats the battery housing and components inside the battery housing, and particles may be deposited on the battery cells. In order to protect the battery cells from this, a cover element can be provided to cover the battery cells on the exhaust side of the battery cells.

[0010] The cover element may include, for example, a non-conductive polymer or mineral plate. However, such materials may not be able to withstand the high temperatures and pressures during thermal runaway and may mechanically decompose. In this case, the exhaust gas flow may reach other battery cells and transfer a large amount of heat energy to the battery cells in contact with them, thereby damaging the cells and possibly promoting the thermal propagation of the runaway event to the remaining cells. In addition, particles of the exhaust gas flow may contaminate the internal components of the battery pack, resulting in conductive paths between metal parts with different electrical potentials (e.g., the housing and electrical connection components such as bus bars). This can lead to the formation of an arc, which further accelerates the thermal propagation of the thermal runaway event to the remaining cells. Summary of the invention

[0011] Embodiments of the present disclosure overcome or mitigate at least some of the disadvantages of the prior art and provide a battery system that more safely handles thermal runaway of one or more of its cells without damaging components of the battery system.

[0012] The present disclosure is defined by the appended claims and their equivalents. The following description is subject to this limitation. Any disclosure outside the scope of the claims is intended for illustration and comparison purposes.

[0013] According to an embodiment of the present disclosure, a battery system for an electric vehicle includes: a plurality of battery cells, each battery cell having an exhaust side, the exhaust side having an exhaust outlet for allowing an exhaust gas flow to exit the battery cell; a housing that accommodates the battery cells; a cover plate that covers the battery cells on the exhaust side to protect the battery cells from exhaust products in the exhaust gas flow, the cover plate having exhaust openings that are respectively aligned with the exhaust outlets for allowing the exhaust gas flow to pass through the cover plate; a thermally insulating sealing layer between the cover plate and the exhaust side of the battery cell, the sealing layer extending around the exhaust outlet; and a mounting assembly that secures the cover plate to the housing so that the cover plate applies pressure to the sealing layer.

[0014] According to an embodiment of the present disclosure, the cover plate may include metal.

[0015] According to an embodiment of the present disclosure, the cover plate may include steel.

[0016] According to an embodiment of the present disclosure, the cap plate may have a bent portion bent toward the battery cell.

[0017] According to an embodiment of the present disclosure, the bent portion may have a trapezoidal shape.

[0018] According to an embodiment of the present disclosure, the cap plate may completely cover the exhaust side of the battery cell.

[0019] According to an embodiment of the present disclosure, battery cells can be interconnected with each other via electrical connection assemblies that contact electrode terminals of the battery cells, and the cover plate can cover the electrode terminals and the electrical connection assemblies so that in the event of thermal runaway, the electrode terminals and the electrical connection assemblies are protected from exhaust products exiting the exhaust outlet of one or more of the battery cells.

[0020] According to an embodiment of the present disclosure, the battery system may further include an insulating layer between the cap plate and the electrical connection assembly.

[0021] According to an embodiment of the present disclosure, the insulating layer may include a ceramic felt layer.

[0022] According to an embodiment of the present disclosure, the sealing layer may include a ceramic fiberboard.

[0023] According to an embodiment of the present disclosure, the cover plate may include an indentation extending around the exhaust opening.

[0024] According to an embodiment of the present disclosure, the exhaust opening in the cover plate may be sealed with a temperature-resistant membrane.

[0025] According to an embodiment of the present disclosure, the cover plate may have a spherical recess that is indented toward the sealing layer, and the spherical recess may extend around at least one of the exhaust openings.

[0026] According to an embodiment of the present disclosure, one or more of the exhaust openings in the cover plate may be surrounded by an inclined outer surface of the cover plate in a plan view, and the inclined outer surface may be inclined toward the one or more of the exhaust openings.

[0027] According to another embodiment of the present disclosure, an electric vehicle may include the battery system as defined above.

[0028] Further aspects and features of the present disclosure will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Aspects and features of the present disclosure will become apparent to those skilled in the art by describing the embodiments in detail with reference to the accompanying drawings, in which:

[0030] Figure 1 is a schematic perspective view of a battery system according to an embodiment.

[0031] Figure 2 yes Figure 1 Schematic cross-sectional view of the battery system shown.

[0032] Figure 3A and Figure 3B According to various embodiments, Figure 1 Vent opening of a cover plate of a battery system shown in FIG.

[0033] Some reference signs

[0034] 12 Battery Cells

[0035] 13 Exhaust side

[0036] 14 Exhaust outlet

[0037] 15 Insulation layer

[0038] 15a Extension of the insulating layer

[0039] 16 Electrode terminal

[0040] 18 Electrical connection components

[0041] 20 Cover

[0042] 22 Exhaust opening

[0043] 22' exhaust opening

[0044] 22'' exhaust opening

[0045] 23'' Spherical recess including exhaust opening

[0046] 24 Curved part of cover

[0047] 24a Bend of the legs

[0048] 24b Base of curved portion

[0049] 25 Protrusion

[0050] 26 Diaphragm

[0051] 30 Sealing layer

[0052] 40 Installing Components

[0053] 42 Mounting Points

[0054] 100 Battery System

[0055] V Exhaust direction DETAILED DESCRIPTION

[0056] Reference will now be made in detail to embodiments, examples of which are shown in the accompanying drawings. Aspects and features of the embodiments and methods of implementing the same will be described with reference to the accompanying drawings. However, the present disclosure may be implemented in a variety of different forms and should not be construed as being limited to the illustrated embodiments. Rather, these embodiments are provided as examples so that the present disclosure will be thorough and complete, and will fully convey the aspects and features of the present disclosure to those skilled in the art.

[0057] Therefore, processes, elements, and techniques that are not considered necessary for a full understanding of the aspects and features of the present disclosure by a person of ordinary skill in the art may not be described. In the accompanying drawings, the relative sizes of elements, layers, and regions may be exaggerated for clarity. For example, in the accompanying drawings, the size or thickness of each element may be arbitrarily shown for illustrative purposes, and therefore the embodiments of the present disclosure should not be construed as being limited thereto.

[0058] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure." In the following description of embodiments of the present disclosure, terms in the singular may include plural forms unless the context clearly indicates otherwise.

[0059] 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. When after a column of elements, expressions such as "at least one of ... " modify the entire column of elements without modifying the individual elements in the column. For example, the expression "at least one of a, b or c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all or their variants of a, b and c. As used herein, the terms "use", "use ... " and "used" can be considered to be synonymous with the terms "utilize", "utilize ... " and "utilized" respectively.

[0060] As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation, not 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 conjunction with a feature that can be expressed using a numerical value, the term "substantially" means a range of + / - 5% of the value centered around that value.

[0061] It will also be understood that the terms “comprises,” “includes,” “including,” or “comprising” indicate attributes, regions, fixed numbers, steps, processes, elements, components, and combinations thereof, but do not exclude other attributes, regions, fixed numbers, steps, processes, elements, components, and combinations thereof.

[0062] It will also be understood that when a film, region or element is referred to as being “on” or “over” another film, region or element, it can be directly on the other film, region or element or intervening films, regions or elements may also be present.

[0063] Here, the terms "upper" or "top" and "lower" or "bottom" are defined according to the z-axis. These terms may refer in particular to the intended installation of the battery system inside an electric vehicle.

[0064] 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.

[0065] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. It will be further 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.

[0066] According to an embodiment of the present disclosure, a battery system is provided. The battery system includes a housing that accommodates a plurality of battery cells, forming a battery housing. The battery cells may be interconnected by electrical connection components (e.g., bus bars) that contact the corresponding electrode terminals of the battery cells to form one or more battery modules / battery packs. The battery cells are arranged to form one or more battery packs in which the battery cells are electrically interconnected (e.g., in series and / or in parallel), as described above. A plurality of battery packs may form a battery module. Two or more battery packs may be stacked to form a single cell stack.

[0067] The battery cells may be, for example, prismatic or cylindrical cells. Each battery cell has an exhaust outlet at an exhaust side of the battery cell, which may be a terminal side of the battery cell. The exhaust outlet allows exhaust gas flow to escape (or exit) the battery cell during thermal runaway. An exhaust valve may be provided at (or in) the exhaust outlet.

[0068] The battery system may further include a cover plate covering at least part of the exhaust side of the battery cell. The cover plate may cover a plurality of battery cells on the exhaust side of the battery cell. The cover plate may be configured to cover all battery cells of the battery pack. In addition, the cover plate may be configured to cover a plurality of battery cells stacked with a plurality of cells, so that a one-piece solution for covering the battery cell may be provided. The cover plate covers the exhaust side around the exhaust outlet. The cover plate has an exhaust opening in the form of a through hole, each of the exhaust openings being aligned with a corresponding one of the exhaust outlets of the battery cell, so that the exhaust gas flow exiting one of the battery cells through the exhaust outlet of the battery cell can pass through the corresponding exhaust opening. The cover plate is mechanically rigid. For example, the cover plate is rigid, at least with respect to the force typically experienced during thermal runaway of one or more battery cells in the battery cell. For example, the cover plate is mechanically rigid so that it can withstand the force typically experienced during thermal runaway of one or more battery cells in the battery cell without substantially bending, breaking, and / or allowing the cover plate to remain structurally integral with the housing to which it is fixed. Such rigidity can be achieved by appropriate selection of material (e.g., steel), thickness of the material, and / or shape of the cover plate, as will be described in further detail below. The cover plate covers a plurality of battery cells at the exhaust side of the battery cells, whereby the cover plate protects the covered battery cells from deposition of exhaust products of the exhaust gas stream. The cover plate is configured to withstand temperatures typically occurring during thermal runaway, such as temperatures of at least about 700° C. to at least about 1000° C.

[0069] A thermally insulating sealing layer is disposed between the cover plate and the exhaust side of the battery cell. The sealing layer provides a seal between the battery cell and the cover plate to prevent exhaust airflow from flowing between the battery cell and the cover plate and to prevent heat transfer from the cover plate to the battery cell. The sealing layer surrounds the exhaust outlet of the battery cell (e.g., extending around the periphery of the exhaust outlet). The sealing layer may also surround the exhaust opening of the cover plate, with the exhaust opening being arranged on the other side of the sealing layer. The sealing layer includes a high temperature resistant sealing material, such as a ceramic fiberboard. The sealing layer is configured to withstand temperatures typically occurring during thermal runaway, that is, temperatures of at least about 700°C to at least about 1000°C.

[0070] According to one or more embodiments of the present disclosure, the cover plate applies pressure (or compression force) to the sealing layer. For example, the cover plate is configured to apply or apply pressure to the sealing layer. The pressure compresses the sealing layer at least to some extent. For example, the sealing layer can be compressed to a certain extent so that sufficient sealing is achieved by applying pressure to the sealing layer by the cover plate. To this end, the battery system may include a mounting assembly that fixes the cover plate to the housing of the battery system. The housing acts as a counter bearing assembly for the mounting assembly / cover plate. The mounting assembly can clamp or press the cover plate against the sealing layer using a corresponding reaction force provided by the housing (that is, a structural portion of the housing to which the mounting assembly is attached). Pressure can also be considered as a clamping force. The pressure applied by the cover plate is high enough to maintain the seal provided by the sealing layer throughout the duration of thermal runaway of one or more battery cells in the battery cell. For example, the minimum pressure sufficient to seal the cover plate to the battery cell is maintained throughout the duration of thermal runaway. Because the cover plate is mechanically rigid, it is suitable for and configured to apply pressure to the sealing layer, that is, to transfer pressure from the mounting assembly to the sealing layer. For example, the cover plate can be configured to apply pressure to the entire area of ​​the sealing layer, rather than just to the area near the mounting point where the mounting assembly contacts the cover plate. For example, a mechanically rigid cover plate is configured to transfer the force applied to the cover plate by the mounting assembly to the entire sealing layer.

[0071] Therefore, the cover plate and the seal provided by the sealing layer can withstand the temperature and pressure that may be generated (e.g., may occur) during thermal runaway of one or more battery cells in the battery cell. Because the cover plate is mechanically rigid and is pressed against and / or clamped on the sealing layer, the opposing force that usually occurs during thermal runaway does not exceed the pressure. More precisely, even during thermal runaway, at least the minimum force applied to the sealing layer from the cover plate still exists. Therefore, the cover plate, the sealing layer, and therefore the seal will not mechanically decompose during thermal runaway. Therefore, the exhaust airflow is prevented from reaching other battery cells, thereby hindering the heat propagation of the runaway event to the remaining cells. In addition, the particles of the exhaust airflow are deposited on the outer surface of the cover plate, so that the battery cells and the sealing layer are protected from its influence. Although this deposit heats the cover plate, the thermally insulating sealing layer prevents or at least reduces the heat transfer from the cover plate to the battery cell, thereby protecting the battery cell.

[0072] According to some embodiments, the cover plate is made of metal. For example, the cover plate can be made of steel, can be a metal plate, or can be a steel plate. The metal (e.g., steel) is suitable for providing hardness to the cover plate, thereby providing a mechanically rigid cover plate. The material thickness and / or shape of the cover plate can be selected based on the material, so that the cover plate has sufficient mechanical rigidity to withstand the forces described above during thermal runaway. According to some embodiments, the cover plate can be a bimetallic plate, such as a steel alloy.

[0073] According to some embodiments, the cover plate has a curved portion that is curved toward the battery cell, that is, toward the exhaust side of the battery cell. The curved portion is curved toward the battery cell to maintain a uniform pressure applied to the sealing layer over the entire area of ​​the sealing layer. The curved portion extends farther toward the exhaust side of the battery cell than the adjacent portion of the adjacent curved portion of the cover plate. The curved portion may form an indentation or groove in the cover plate, the base of which contacts the sealing layer. The curved portion is formed in the cover plate during the manufacture of the cover plate, and can therefore be considered as a pre-bent portion. The curved portion may be arranged at an area of ​​the cover plate between the mounting points where the mounting assembly contacts the cover plate (e.g., in the middle between two mounting assemblies). Therefore, the curved portion of the cover plate is bent toward the battery cell between the mounting positions of the first and second mounting assemblies. The curved portion ensures uniform compression of the sealing layer over the entire area of ​​the sealing layer. For example, the curved portion allows the cover plate to apply or transfer pressure to the sealing layer over the entire length and / or area of ​​the sealing layer. In the absence of such a curved portion, the cover plate may only apply sufficient pressure to the battery cell or the portion of the battery cell close to the mounting assembly. Thus, the outer battery cells or only the outer edges of the sealing layer in the lateral direction will have sufficient sealing.With the cover plate having a curved portion, sufficient sealing during thermal runaway is maintained over the entire extension of the sealing layer.

[0074] According to some embodiments, the bent portion has a trapezoidal shape. For example, the bent portion forms a trapezoidal depression toward the battery cell, the base of which contacts the sealing layer. The trapezoidal shape of the bent portion has a base and two legs interconnected by the base. The legs are oppositely inclined and form an undercut with respect to an adjacent portion of the cover plate relative to a vertical axis. For example, the width of the depression or groove formed by the bent portion is larger the closer to the battery cell and smaller the farther away from the battery cell. The bent portion having such a trapezoidal shape ensures that pressure is applied to the sealing layer evenly over the entire area of ​​the sealing layer.

[0075] According to some embodiments, the cover plate completely covers the exhaust side of the battery cell. For example, the cover plate extends along the entire / entire exhaust side of the battery cell. The cover plate may completely (or entirely) cover the battery cell on the upper or lower side of the battery cell. For example, except for the exhaust opening, the cover plate completely covers the exhaust side of the battery cell side, so that the exhaust airflow leaving one or more of the battery cells through their respective exhaust outlets can still pass through the cover plate. The cover plate that completely covers the battery cell shields (e.g., protects) the battery cell from the exhaust airflow and prevents the exhaust products (such as particles) from being deposited on the battery cell. The cover plate may also cover the electrical connection components that interconnect the battery cells.

[0076] According to some embodiments, the battery cells are interconnected by electrical connection assemblies that contact the electrode terminals of the battery cells. In the event of thermal runaway, when the exhaust products are deposited on the cover plate, the cover plate protects the electrode terminals and the electrical connection assemblies from the exhaust products exiting the exhaust outlet of one or more battery cells in the battery cells. As described above, the electrical connection assembly can be, for example, a bus bar connecting the electrode terminals of the battery cells. According to some embodiments, the cover plate also protects the electrode terminals and the electrical connection assemblies, protecting them from the exhaust gas flow, particularly from the exhaust products that would otherwise be deposited on the electrode terminals and the electrical connection assemblies in the event of thermal runaway. This prevents damage to the electrode terminals and the electrical connection assemblies. In addition, this prevents short circuits or arc discharges between the electrical connection assemblies that would otherwise cause further damage.

[0077] According to some embodiments, the battery system further includes an insulating layer arranged between the cover plate and the electrical connection assembly. The insulating layer may be an insulating layer of electrical insulation and / or thermal insulation. For example, one or more such insulating layers may be provided for each electrical connection assembly. For example, two electrical connection assemblies connected to the two electrode terminals may be provided with such an insulating layer. In some embodiments, the cover plate covers the electrode terminal and the electrical connection assembly, and the insulating layer is provided between them. The insulating layer may extend along one or more sides of the electrical connection assembly. In addition, the insulating layer may extend along the side of the electrode terminal. The insulating layer may extend from the electrical connection assembly and the electrode terminal to the exhaust side (that is, toward the exhaust side of the battery cell and contact the exhaust side). The insulating layer may include one or more of a ceramic felt layer, a ceramic fiber wool, a needle felt or an expanded polymer material. These are suitable for electrical / thermal insulation of the electrode terminal and the electrical connection assembly. According to some embodiments, the insulating layer protects the electrode terminal and the electrical connection assembly from heat transfer or electrical conduction from the cover plate that may otherwise occur due to the deposition of the exhaust product on the cover plate. Furthermore, when extended to the exhaust side, such an insulating layer can prevent the electrode terminals and electrical connection components from being contaminated by exhaust gases that would otherwise leak through the compressed sealing layer. A cover plate secured to the housing of the battery system via a mounting assembly can also apply pressure to the insulating layer, thereby maintaining insulation of the electrode terminals and electrical connection components, particularly during thermal runaway.

[0078] According to some embodiments, the sealing layer includes a ceramic fiberboard, wherein ceramic fibers may be embedded in a matrix such as a resin. The ceramic fiberboard is suitable for thermal insulation and for withstanding the high temperatures that occur during thermal runaway. In addition, the ceramic fiberboard is compressible enough to achieve the above-mentioned sealing and can withstand the pressure and temperature of thermal runaway.

[0079] According to some embodiments, the cover plate comprises an impression around the exhaust outlet, such as an edge-shaped impression. Such an impression can increase the pressure on the sealing layer.

[0080] According to some embodiments, the exhaust outlet of the cover plate is sealed with a temperature-resistant membrane. The membrane can be, for example, a mica sheet, that is, a mica silicate mineral sheet. Such a membrane seals the exhaust opening and thus prevents any external contamination, such as moisture or other particles, from entering the battery cell through its exhaust outlet during normal operation. The membrane is configured to rupture (e.g., burst) during a thermal runaway event. For example, the exhaust gas flow leaving the exhaust outlet of one or more of the battery cells will rupture the membrane, thereby allowing the exhaust gas flow to pass through the exhaust opening and thus through the cover plate.

[0081] According to some embodiments, one or more of the exhaust openings of the cover plate are respectively surrounded by an inclined outer surface of the cover plate (e.g., surrounded in a plan view), and the inclined outer surface may be inclined toward the exhaust outlet. That is, the outer surface of the cover plate surrounding the exhaust opening may be tapered toward the exhaust opening or may be funnel-shaped toward the exhaust opening. Therefore, when viewed along the exhaust direction, the cross-section of the exhaust opening may be widened. This may allow for improved exhaust of the exhaust airflow exiting through the exhaust opening, because the exhaust airflow may quickly expand to all sides due to the widened cross-section.

[0082] According to some embodiments, the cover plate includes at least one spherical depression that is indented toward the sealing layer. The spherical depression has at least one of the exhaust openings. For example, one or more of the exhaust openings of the cover plate can be arranged at the bottom of the corresponding spherical depression in the cover plate. That is, the spherical depression can form a recessed portion of the cover plate and can have an exhaust opening. For each exhaust opening, one such spherical depression can be provided. The spherical depression indented toward the sealing layer locally increases the contact pressure on the sealing layer around the exhaust outlet of the battery cell, thereby further improving the seal.

[0083] The embodiments of the present disclosure are also applicable to an electric vehicle including the above-mentioned battery system.

[0084] Figure 1 and Figure 2 A battery system 100 according to an embodiment of the present disclosure is schematically illustrated. The battery system 100 comprises a battery housing accommodating a plurality of battery cells 12. For illustrative purposes, only four battery cells 12 are shown, of which only two are provided with reference numerals.

[0085] Each battery cell 12 includes two electrode terminals 16 connected to each other via an electrical connection assembly 18 such as a bus bar (see, e.g., Figure 2 )) are interconnected with electrode terminals 16 of adjacent battery cells 12. The battery cells 12 are thus arranged to form one or more battery packs. Each battery cell 12 has an exhaust side 13 with an exhaust outlet 14 for allowing exhaust gas flow to exit the battery cell 12 in the event of thermal runaway inside the corresponding battery cell 12.

[0086] The battery system 100 further includes a mechanically rigid cover plate 20 that completely (or fully) covers the plurality of battery cells 12 at the exhaust side 13 of the plurality of battery cells 12, that is, the cover plate 20 extends substantially along the x-axis and along the y-axis (e.g., see Figure 1 ), so that it completely covers the plurality of battery cells 12. The cap plate 20 has a protruding portion 25 that extends over and covers the electrode terminal 16 and the electrical connection assembly 18, respectively (see, for example, Figure 2 ). The cover plate 20 has exhaust openings 22 that are respectively aligned with the exhaust outlets 14 to allow exhaust airflow to pass through the cover plate 20. Therefore, the cover plate 20 completely covers the battery cell 12 at the exhaust side 13 of the battery cell 12, except for the exhaust outlets 14, because the exhaust outlets 14 are aligned with the exhaust openings 22 in the cover plate 20. Therefore, during thermal runaway, the exhaust airflow that leaves one or more of the battery cells 12 through its exhaust outlet 14 can pass through the corresponding exhaust openings 22 to the outside of the cover plate 20.

[0087] In addition, the cover plate 20 has a curved portion 24 having a trapezoidal shape. The curved portion 24 has two legs 24a interconnected by a base 24b. Below the base 24b, a thermally insulating sealing layer 30 is arranged on top of the battery cell 12, and thus between the cover plate 20 and the exhaust side 13 of the battery cell 12. The sealing layer 30 surrounds the exhaust outlet 14 (e.g., extends around the periphery of the exhaust outlet 14). That is, the sealing layer 30 has an opening 30a through which the exhaust gas flow leaving the exhaust outlet 14 can pass.

[0088] The mounting assembly 40 is attached to the cover plate 20 at mounting points 42 at opposite ends of the cover plate 20. The mounting assembly 40 is formed by pressing or clamping the cover plate 20 against the housing so that the cover plate 20 applies a pressure F (at Figure 2 The cover plate 20 is fixed to the housing of the battery system 100 by applying a force (indicated by a dotted arrow) to the sealing layer 30. For example, the housing acts as a counter-support component for the mounting component 40, so that the mounting component can apply a force to the cover plate 20, and the cover plate 20 can in turn apply pressure to the sealing layer 30. Therefore, the cover plate 20 compresses the sealing layer 30, which can be, for example, a ceramic fiberboard.

[0089] This improves the seal, preventing exhaust gas flow from entering between the cover plate 20 and the exhaust side 13 of the battery cell 12. In addition, the sealing layer 30 thermally insulates the battery cell 12 from the cover plate 20, thereby preventing or reducing heat transfer from the cover plate 20 to the exhaust side 13. Therefore, the battery cell 12 is protected from any exhaust products deposited on the cover plate 20, and no heat is transferred from the cover plate 20 heated by the exhaust products. Because the cover plate 20 is mechanically rigid and is pressed against (or clamped) the sealing layer 30 by the mounting assembly 40, even the reverse force that occurs during thermal runaway does not exceed the pressure. The curved portion 24 allows the cover plate 20 to apply uniform pressure to the entire area of ​​the sealing layer 30, not just near the mounting assembly 40. For example, due to the shape of the cover plate 20, the cover plate 20 can effectively and uniformly transfer the force received via the mounting assembly 40 to the sealing layer 30.

[0090] As a result, the cover plate 20 and the seal provided by the sealing layer 30 can withstand the temperatures and pressures that may be generated during thermal runaway of one or more of the battery cells 12. Therefore, the cover plate 20, the sealing layer 30, and the seal will withstand thermal runaway. Therefore, the exhaust gas flow is prevented from reaching other battery cells 12, and the heat propagation of the runaway event is prevented from reaching or affecting the remaining battery cells. In addition, particles from the exhaust gas flow are deposited on the outer surface of the cover plate 20, protecting the battery cells 12 and the sealing layer 30 from their influence. Although such deposits heat the cover plate 20, the thermally insulating sealing layer 30 prevents or at least reduces the heat transfer from the cover plate 20 to the battery cells 12, thereby protecting the battery cells 12.

[0091] The battery system 100 further includes an insulating layer 15 disposed between the cover plate 20 at the protruding portion 25 thereof and the electrical connection assembly 18. The insulating layer 15 is an insulating layer that is electrically and thermally insulating. Figure 2 As shown, the insulating layer 15 extends onto the exhaust side 13 along the inner side of the electrical connection assembly 18 and the electrode terminal 16 through the extension portion 15a. The insulating layer 15 protects the electrode terminal 16 and the electrical connection assembly 18 from heat transfer and electrical conduction from the cap plate 20. In addition, because the extension portion 15a extends onto the exhaust side 13, the insulating layer 15 prevents the electrode terminal 16 and the electrical connection assembly 18 from being contaminated by exhaust gas, which would otherwise leak through the compressed sealing layer 30.

[0092] Furthermore, the cap plate 20 applies pressure to the insulating layer 15 via the protruding portion 25 thereof, thereby maintaining insulation of the electrode terminal 16 and the electrical connection assembly 18 even during thermal runaway.

[0093] The exhaust openings 22 in the cover plate 20 are each sealed by a temperature-resistant membrane 26, preventing any external contaminants such as moisture or other particles from entering the battery cell 12 through its exhaust outlet 14 during normal operation. The membrane 26 is configured to rupture during a thermal runaway event. In other words, the exhaust gas flow leaving the exhaust outlet 14 of one or more of the battery cells 12 will rupture the membrane 26 and thus pass through the exhaust opening 22, and thus through the cover plate 20.

[0094] Figure 3A and Figure 3B Exhaust openings 22' and 22" in the cover plate 20 are shown according to various embodiments. Figure 3A and Figure 3B In FIG. 2 , the cover plate 20 is partially shown, so that only one exhaust opening 22 ′ or 22 ″ is visible.

[0095] exist Figure 3AIn the illustrated embodiment, an outer surface of the cover plate 20 surrounding the exhaust opening 22' (e.g., extending around the periphery of the exhaust opening 22') is inclined toward the exhaust opening 22'. For example, the outer surface of the cover plate 20 surrounding the exhaust opening 22' is tapered or funnel-shaped toward the exhaust opening 22'. As a result, the cross section of the exhaust opening 22' widens when viewed along the exhaust direction V. This may allow for improved exhaust of the exhaust airflow exiting through the exhaust opening 22', since the exhaust airflow may quickly expand to all sides due to the widened cross section.

[0096] exist Figure 3B In the illustrated embodiment, the cover plate 20 has a spherical depression 23" that is indented toward the sealing layer 30, and the spherical depression 23" has a vent opening 22". For example, the vent opening 22" in the cover plate 20 is arranged at the bottom of the spherical depression 23". That is, the spherical depression 23" forms a recessed portion of the cover plate 20 and has the vent opening 22". Since the spherical depression 23" is indented toward the sealing layer 30, this embodiment locally increases the contact pressure on the sealing layer 30 around the vent outlet 14 of the battery cell 12, thereby further improving the seal.

Claims

1. A battery system for an electric vehicle, the battery system comprising: a plurality of battery cells, each of the battery cells having an exhaust side with an exhaust outlet for allowing exhaust gas flow to exit the battery cell; A housing for accommodating the battery cell; a cover plate covering the battery cell at the exhaust side to protect the battery cell from exhaust products in the exhaust gas flow, the cover plate having exhaust openings respectively aligned with the exhaust outlets for allowing the exhaust gas flow to pass through the cover plate; a thermally insulating sealing layer between the cover plate and the exhaust side of the battery cell, the sealing layer extending around the exhaust outlet; as well as An assembly is mounted to secure the cover plate to the housing so that the cover plate applies pressure to the sealing layer. The battery system according to claim 1 , wherein the cover plate comprises metal. The battery system of claim 2 , wherein the cover plate comprises steel. 4 . The battery system according to claim 1 , wherein the cap plate has a bent portion bent toward the battery cell. The battery system according to claim 4 , wherein the bent portion has a trapezoidal shape. The battery system according to claim 1 , wherein the cover plate completely covers the exhaust side of the battery cell.

7. The battery system according to claim 1, wherein the battery cells are interconnected with each other via electrical connection components contacting electrode terminals of the battery cells, and The cap plate covers the electrode terminals and the electrical connection assembly so that in the event of thermal runaway, the electrode terminals and the electrical connection assembly are protected from exhaust products exiting the exhaust outlet of one or more of the battery cells. 8 . The battery system according to claim 7 , further comprising an insulating layer between the cap plate and the electrical connection assembly.

9. The battery system of claim 8, wherein the insulating layer comprises a ceramic felt layer.

10. The battery system of claim 1, wherein the sealing layer comprises a ceramic fiberboard.

11. The battery system of claim 1, wherein the cover plate includes an indentation extending around the vent opening.

12. The battery system according to claim 1, wherein the vent opening in the cover plate is sealed with a temperature-resistant membrane.

13. The battery system according to claim 1, wherein the cover plate has a spherical depression indented toward the sealing layer, and Wherein the spherical recess extends around at least one of the exhaust openings.

14. The battery system according to claim 1, wherein one or more of the exhaust openings in the cover plate are surrounded by an inclined outer surface of the cover plate in plan view, and Wherein the inclined outer surface is inclined towards the one or more of the exhaust openings.

15. An electric vehicle comprising the battery system according to claim 1.

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