Battery system and electric vehicle comprising the same

Abstract

The present disclosure relates to a battery system and an electric vehicle comprising the battery system. The battery system comprises a plurality of battery cells arranged in a cell stack, a cell stack frame accommodating the cell stack and exerting a pressure on the cell stack, and a cooling structure comprising a plurality of cooling plates. Each cooling plate is arranged between adjacent battery cells and comprises two plate elements with a cooling chamber for coolant flow therebetween and a compression structure arranged inside the cooling chamber. The compression structure is configured such that it plastically deforms in response to a compression force acting on the plate elements of the cooling plate.

Description

Technical Field

[0001] The embodiments of this disclosure relate to battery systems and electric vehicles including such battery systems. Background Technology

[0002] Recently, vehicles using electricity as a power source for transporting goods and people have been developed. Electric vehicles are automobiles propelled by electric motors using energy stored in rechargeable batteries (or secondary batteries) for sustained or temporary propulsion. Electric vehicles can be powered solely by batteries (so-called battery electric vehicles (BEVs)) or can include a combination of an electric motor and, for example, a conventional internal combustion engine (so-called plug-in hybrid electric vehicles (PHEVs)). BEVs and PHEVs use high-capacity rechargeable batteries designed to provide power for propulsion over a sustained period of time.

[0003] Typically, a rechargeable (or secondary) battery cell includes an electrode assembly comprising a positive electrode, a negative electrode, and a separator interposed between the electrodes. A solid or liquid electrolyte allows ions to move during the charging and discharging of the battery cell. The electrode assembly is housed within a casing (or housing), and electrode terminals located outside the casing establish conductive connections with the electrodes. Common battery cell forms include, for example, cylindrical, prismatic, and pouch-shaped cells.

[0004] A battery module is formed by (or includes) multiple battery cells connected in series or parallel. A battery module is formed by interconnecting the electrode terminals of multiple battery cells; the number of battery cells and their connection arrangement depend on the desired power capacity to achieve a relatively high-power rechargeable battery.

[0005] Battery modules can be constructed using either a block design or a modular design. In a block design, each battery cell is integrated into a common current collector structure and a common cell management unit and housed within a casing. In a modular design, multiple battery cells are connected together to form sub-modules, and several sub-modules are connected together to form a battery module. In automotive applications, battery systems may include multiple battery modules connected in series to provide a desired voltage.

[0006] A battery pack is a group of any number (typically identical) battery modules and / or a single (e.g., an individual) battery cell. Battery modules, or correspondingly, battery cells, can be configured in series, parallel, or a combination of both to provide desired voltage, capacity, and / or power density. The components of a battery pack include individual battery modules and interconnects that provide conductivity between the battery modules.

[0007] The mechanical integration of the battery pack is achieved through appropriate mechanical connections between individual components, such as between battery modules and between battery modules and the vehicle's support structure. These connections should remain functional and safe throughout the average lifespan of the battery system. Furthermore, installation space and interchangeability specifications should be met, especially in mobile applications.

[0008] Mechanical integration of the battery module can be achieved by providing a carrier frame and positioning the battery module thereon. Securement of individual battery cells or the battery module can be achieved through mating recesses in the frame or via mechanical interconnects such as bolts or screws. In some cases, the battery module is confined by fastening side panels to the sides of the carrier frame. Additionally, cover plates can be fixed to the top and bottom of the battery module.

[0009] The battery pack's carrier frame is mounted to the vehicle's load-bearing structure. When the battery pack needs to be secured to the bottom of the vehicle, a mechanical connection can be established from the bottom side via bolts, for example, passing through the carrier frame. The frame is typically made of aluminum or aluminum alloy to reduce the overall weight of the structure.

[0010] Traditional battery systems, regardless of their modular structure, typically include a battery casing that acts as an enclosure to seal the battery system relative to the environment and provide structural protection for the system's components. Encapsulated battery systems are usually installed as a whole (e.g., as a single unit) in their application environment, such as electric vehicles. Therefore, replacing a defective system component, such as a defective battery sub-module, requires first disassembling the entire battery system and removing its casing. Even defects in small and / or inexpensive system components may necessitate the disassembly and replacement of the entire battery system and its individual repair. This process is cumbersome because high-capacity battery systems are expensive, large, and heavy, and storing bulky battery systems, for example, in a mechanic's shop is difficult.

[0011] Active or passive thermal management systems can be included to provide thermal control of the battery pack, thereby ensuring the safe use of at least one battery module by effectively dissipating, releasing, and / or dissipating heat generated by its rechargeable cells. Without adequate heat dissipation, release, and / or dissipation, temperature variations can occur between individual battery cells, causing at least one battery module to cease generating the desired (or designed) amount of charge. Furthermore, elevated internal temperatures can lead to abnormal reactions, thus degrading the charging and discharging performance of the rechargeable battery and shortening its lifespan. Therefore, cell cooling for effectively dissipating, releasing, and / or dissipating heat from the battery cells is crucial.

[0012] Exothermic decomposition of a single cell can lead to what is known as thermal runaway. Generally, thermal runaway describes a process accelerated by rising temperatures, releasing energy that further increases the temperature. Thermal runaway occurs when conditions change in a way that leads to a further increase in temperature, often resulting in destructive consequences. In rechargeable battery systems, thermal runaway is associated with a violently exothermic reaction accelerated by rising temperatures. In thermal runaway, the temperature of a single cell rises very rapidly, and the stored energy is released very suddenly. In extreme cases, thermal runaway can cause a single cell to explode and catch fire. In less severe cases, thermal runaway can cause irreparable damage to the single cell.

[0013] When a battery cell is heated above its critical temperature (e.g., above approximately 150°C), it can enter thermal runaway. Temperatures outside the safe zones on the low or high side can typically cause irreversible damage to the battery cell, potentially triggering thermal runaway. Thermal runaway can also occur due to internal or external short circuits within the battery cell or poor battery maintenance. For example, overcharging or fast charging can lead to thermal runaway.

[0014] During thermal runaway, the faulty battery cell can reach temperatures exceeding approximately 700°C. Furthermore, a large amount of hot gas is ejected from the inside of the faulty cell through venting openings in the cell casing into the battery pack. The main components of the emitted gases are H2, CO2, CO, electrolyte vapor, and other hydrocarbons. Therefore, the emitted gases are flammable and potentially toxic. The emitted gases also cause an increase in gas pressure within the battery pack. In the worst-case scenario, the high temperature causes the process to spread to adjacent cells and ignite within the battery pack. At this stage, the fire is very difficult to extinguish.

[0015] The battery cells of a battery pack can be arranged to form a cell stack by stacking the cells on top of each other or by arranging the cells in rows and placing the cell stack within a cell stacking frame. Adjacent cells in such a cell stack can be separated from each other by cell separators (e.g., spaced apart). To ensure optimal operation of the cell cells throughout their lifespan, a reference (or predetermined) pressure can be applied to the cell cells through the cell stacking frame to compensate for possible manufacturing tolerances and expansion of the cell cells.

[0016] Current battery systems typically include a cell stack frame with end plates, which in some cases apply pressure to the cell stack via end separators with either a rigid linear pressure characteristic or a progressively elastic pressure characteristic. This rigid linear or progressively elastic pressure characteristic can be susceptible to length or positioning deviations, as small displacements can cause a sharp increase or decrease in the force applied to the cell stack, which in turn degrades stack performance. To mitigate this, very precise and therefore expensive manufacturing tolerances must be met, or other expensive and complex methods must be implemented to adjust the cell stack preload force during assembly via the positioning of the end plates. Such a cell stack frame may not guarantee that adequate pressure is applied to the cell stack throughout its entire lifespan. Summary of the Invention

[0017] According to an embodiment of this application, a battery system is provided that ensures suitable pressure and temperature conditions for optimal operation of the battery cell throughout its entire lifespan.

[0018] This 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 and their equivalents is intended for illustrative and comparative purposes.

[0019] According to an embodiment of this disclosure, a battery system includes: a plurality of battery cells arranged in a cell stack; a cell stack frame for housing the cell stack and applying pressure to the cell stack; and a cooling structure including a plurality of cooling plates disposed between adjacent battery cells. Each cooling plate includes two plate elements having a cooling chamber for coolant flow therethrough and a compression structure disposed inside the cooling chamber. The compression structure is configured such that it plastically deforms in response to a compressive force acting on the plate elements of the cooling plate.

[0020] According to embodiments of this disclosure, the cooling structure further includes a curved connecting element that extends around (or around) the end side of the battery cell and interconnects adjacent cooling plates in the cooling plate, such that the cooling structure has a meandering form.

[0021] According to an embodiment of this disclosure, the monolithic stack frame includes end plates on which pressure is applied to the monolithic stack.

[0022] According to an embodiment of the present disclosure, the end plate is formed correspondingly to the adjacent side of the outermost cooling plate at its inner side facing the outermost cooling plate.

[0023] According to embodiments of this disclosure, the cooling structure further includes a fluid inlet element disposed at a first end of the monomer stack and a fluid outlet element disposed at a second end of the monomer stack. The cooling structure is configured to allow coolant to flow from the fluid inlet element through a cooling chamber of a cooling plate and out of the fluid outlet element.

[0024] According to an embodiment of this disclosure, the cooling plate is an extruded plate.

[0025] According to an embodiment of this disclosure, the cooling plate is made of aluminum.

[0026] According to embodiments of this disclosure, the compression structure includes a plurality of support frames distributed on the inner surfaces of two plate elements and extending between the two plate elements.

[0027] According to embodiments of the present disclosure, the compression structure includes one or more of the following: a compression element having a rectangular cross-section, a compression element having a bottleneck-shaped cross-section, a compression element having a semi-circular cross-section, a compression element having a tent-shaped cross-section, a compression element having a rhomboid cross-section, and a compression element having a rhomboid cross-section with a circular end.

[0028] Another embodiment of this disclosure provides an electric vehicle including the battery system described above.

[0029] Other aspects, features, and implementations of this disclosure may be learned from the following description. Attached Figure Description

[0030] The aspects and features of this disclosure will become apparent to those skilled in the art from the detailed description of embodiments thereof with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a perspective view of a battery system according to an embodiment.

[0032] Figure 2 yes Figure 1 The battery system shown is shown in top view.

[0033] Figure 3 yes Figure 1 The diagram shows a perspective view of the battery system, with one of the end plates removed.

[0034] Figure 4 It shows Figure 1 The diagram shows the meandering cooling structure of the battery system.

[0035] Figure 5 It is along the three different compression stages according to the implementation method. Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure, taken from line AA.

[0036] Figure 6 According to another embodiment, it is along three different compression stages. Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure, taken from line AA.

[0037] Figure 7 According to another embodiment, it is along three different compression stages. Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure, taken from line AA.

[0038] Figure 8 According to another embodiment, it is along three different compression stages. Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure, taken from line AA.

[0039] Figure 9 It is according to another embodiment along Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure taken from line AA, as well as a detailed view of the compression structure.

[0040] Figure 10 It is according to another embodiment along Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure taken from line AA, as well as a detailed view of the compression structure.

[0041] Figure 11 It is according to another embodiment along Figure 4 The image shows a cross-sectional view of the cooling plate of the cooling structure taken from line AA, as well as a detailed view of the compression structure.

[0042] Figure 12 This is a top view of a battery system according to another embodiment.

[0043] Figure 13 It is a graph depicting the ratio of force to elongation (displacement) of a battery system according to an embodiment of the present disclosure. Detailed Implementation

[0044] Description of embodiments will now be given in detail, examples of which are illustrated in the accompanying drawings. Aspects and features of the embodiments and methods of implementation thereof will be described with reference to the drawings. However, this disclosure may be implemented in a variety of different forms and should not be construed as limited to the embodiments shown herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete and will fully convey to those skilled in the art the aspects and features of this disclosure.

[0045] Therefore, processes, elements, and techniques not considered essential to a full understanding of the aspects and features of this disclosure by one of ordinary skill in the art may be omitted or only briefly described. In the accompanying drawings, the relative dimensions of elements, layers, and regions may be exaggerated for clarity. The same reference numerals denote the same elements.

[0046] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. When a statement such as “at least one of…” follows a list of elements, it modifies the entire list of elements, not individual elements within that list. Furthermore, when describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” In the following description of embodiments of this disclosure, singular terms may include plural forms unless the context clearly indicates otherwise. For example, the statement “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 a, b, and c, or variations thereof. As used herein, the terms “use,” “using…,” and “being used” may be considered synonymous with the terms “utilize,” “using…,” and “being exploited,” respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms, not terms of degree, and are intended to describe inherent biases in measurements or calculations that would be recognized by one of ordinary skill in the art.

[0047] 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 used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first element may be named a second element, and similarly, a second element may be named a first element.

[0048] It will be further understood that the terms “comprising,” “including,” “including…” and / or “containing…” specify the stated properties, areas, fixed quantities, steps, processes, elements, components, and combinations thereof, but do not exclude other properties, areas, fixed quantities, steps, processes, elements, components, and combinations thereof.

[0049] The term "consistently composed of" means that certain other components may be present, namely those that do not substantially affect the essential properties of the composition.

[0050] It will also be understood that when a membrane, region, or element is referred to as being "above" or "on" another membrane, region, or element, it may be directly on the other membrane, region, or element, or there may be an intermediate membrane, region, or element.

[0051] In this document, the terms "upper" and "lower" are defined according to the z-axis. For example, the upper cover is positioned above the z-axis, while the lower cover is positioned below it. In the accompanying drawings, the dimensions of the components may be exaggerated for clarity. For example, the dimensions or thickness of each component may be arbitrarily shown in the drawings for illustrative purposes, and therefore the embodiments of this disclosure should not be construed as limited thereto.

[0052] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms such as those defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the relevant field and / or the context of this specification, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0053] Those skilled in the art will understand that, in view of the entirety of this disclosure, each suitable feature of the various embodiments of this disclosure may be combined in part or in whole, or combined with one another, and may be technically interlocked and operated in various suitable ways, and each embodiment may be implemented independently or in combination with one another in any suitable manner, unless otherwise stated or implied.

[0054] Furthermore, any numerical range disclosed and / or described herein is intended to include all subranges containing the same numerical precision within said range. For example, the range “1.0 to 10.0” is intended to include all subranges between (and including) said minimum value 1.0 and said maximum value 10.0, i.e., all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly describe any subranges contained within the range expressly described herein.

[0055] According to embodiments of this disclosure, a battery system includes multiple battery cells, such as prismatic or pouch-shaped battery cells. The battery cells are arranged, for example, by stacking the battery cells on top of each other or arranging the battery cells in rows, to form a cell stack. The cell stack can form one or more battery packs. The cell stack is disposed (or arranged) within a cell stack frame. The cell stack frame applies pressure to the cell stack. For example, the cell stack frame may include at least one end plate that applies pressure to the cell stack. The cell stack frame may include two end plates and two sidewalls connecting the end plates. One or both end plates may apply pressure to the cell stack. The cell stack arranged within the cell stack frame may be demarcated from four sides by the end plates and sidewalls. The cell stack frame may also include a top cover and a bottom cover, such that the cell stack can be demarcated on all six sides. At least one end plate may be secured to the sidewalls (and / or the top and bottom covers) for example by riveting or threaded connections. At least one end plate may be rigid, i.e., non-deformable. The cell stack frame may demarcate the cell stack from the outside, for example, from the environment of the cell stack. The at least one end plate can form the outer boundary of the monolithic stacked frame. Furthermore, the other end plate and / or sidewall can form the outer boundary of the monolithic stacked frame. In other words, the monolithic stacked frame (e.g., two end plates and two sidewalls) can demarcate the internal space of the monolithic stacked frame from the external space, and the monoliths are arranged in the internal space.

[0056] The battery system also includes a cooling structure. The cooling structure comprises multiple cooling plates and is configured to cool individual battery cells via the cooling plates. One of the cooling plates is arranged between each pair of battery cells. For example, the cooling plates and battery cells are arranged alternately. The cooling plates form cell spacers that separate adjacent battery cells from each other. The cooling plates can be considered as forming part of a cell stack and are compressed together with the battery cells by a cell stack frame. In other words, the cell stack frame applies pressure not only to the battery cells but also to the cooling plates disposed between the battery cells. Each cooling plate comprises two plate elements. A first plate element of the two plate elements may face and contact a first battery cell of the plurality of battery cells, and a second plate element of the two plate elements may face and contact a second battery cell of the plurality of battery cells. Each cooling plate has a cooling chamber through which a coolant (such as a cooling fluid) may pass, for example, pumped through the cooling chamber, to cool the cooling plate and thereby cool adjacent battery cells during normal operation of the battery system. The cooling structure ensures that the battery cells are maintained within the required or expected temperature range for normal operation.

[0057] Furthermore, according to embodiments of this disclosure, each cooling plate includes a compression structure disposed within a cooling chamber. The compression structure is configured to deform based on external pressure or force acting on the two plate elements. Therefore, the cooling plate is deformable. The compression structure may include, for example, a support frame or partition wall between the two plate elements, which can interconnect the two plate elements. The support frame between the two sides of the cooling plate can, on the one hand, prevent the formation of a direct load path, and on the other hand, provide a substantially uniform pressure distribution across the entire cooling plate. The compression structure disposed within the cooling chamber is configured such that the flow of coolant through the cooling chamber is substantially unimpeded. The compression structure can form cooling channels within the cooling chamber.

[0058] According to embodiments of this disclosure, the compression structure is designed to plastically deform in response to compressive forces acting on the plate elements of the cooling plate. For example, the compression structure—and therefore the cooling plate—is plastically deformable or configured to plastically deform. The compression structure is plastically deformable at least within the operating pressure range of the battery cells. In other words, the cooling plate has plastic deformation characteristics due to the compression structure, e.g., constant or substantially constant plastic deformation characteristics. In other words, the compression structure is designed such that when the cell stack is exposed to increased compressive forces, for example, due to expansion associated with the aging of the battery cells, the cooling plate will plastically deform at least within a predetermined operating pressure range of the battery cells. That is, the battery cells of the cell stack receive preload through the cell stack frame (e.g., by end plates of the cell stack frame pressing against the cell stack), as described above. Preload refers to the precompression applied to the cell stack. Therefore, the battery cells are under operating pressure that should be maintained within a predetermined range depending on, for example, the type, size, and geometry of the battery cells, to ensure the intended operation of the battery cells. However, during their lifespan, individual cells may expand due to aging effects, which—in known battery system designs—can increase the pressure inside (or on) the cell stack.

[0059] However, in the battery system according to embodiments of this disclosure, this expansion of the battery cell is at least partially compensated for by a compressive structure capable of plastic deformation. For example, as the battery cell expands and thus increases in thickness, the cooling plate is compressed and thus decreases in thickness by, for example, the same or nearly the same amount as the increase in thickness of the battery cell. During this compression, the cooling plate does not exert increased pressure on the battery cell (unlike in the case of known cell separators with progressive deformation characteristics), but rather exerts substantially the same pressure throughout the compression range. For example, the compressive structure is shaped or designed such that direct load transfer between plate elements is not permitted within the designed compression / plastic deformation range. In other words, although the battery cell can expand, the pressure within the cell stack frame can remain substantially constant. This results in a constant or only slightly linearly increasing force acting on the battery cell over a large range of compression distance / thickness reduction of the cooling plate and therefore over a large range of aging-related changes in the stack length of the cell stack. Therefore, the cell stack can be safely maintained within the ideal cell stack preload range throughout its lifespan. In other words, the plastically deformable compression structure provides the battery system with deformable characteristics, resulting in very similar compressive forces, independent of variations in the stacked cell length caused by manufacturing tolerances and / or expansion of the individual cells. In other words, due to the deformable cooling plate, the cell stacking frame can apply constant compressive forces to the cell stack within the relevant preload range of prismatic or pouch-shaped cells. The unavoidable tolerances of both the elements of the cell stack and the elements of the cell stacking frame can be compensated for by the inherent deformability of the cooling plate. This eliminates the need for additional filler or other adjustment work during cell stacking. Furthermore, any expansion of the individual cells in the cell stack (which could be due to, for example, aging) can be compensated for. Moreover, because the compression structure is integrated into the cooling plate, installation space is used efficiently, as the cooling plate performs the dual function of cooling the individual cells and acting as a separator for the plastically deformable cells.

[0060] According to one embodiment, the cooling structure further includes a curved connecting element that extends around (or around) the end face of the battery cell and interconnects adjacent cooling plates among a plurality of cooling plates, giving the cooling structure a meandering form. In other words, the cooling plates of the cooling structure, together with the connecting element, can form a continuous passage or channel for coolant to flow through the battery system. The coolant can flow from an inlet through the cooling plates and connecting element to an outlet. As described above, the cooling plates and battery cells are arranged alternately. Two adjacent cooling plates, together with their interconnecting connecting element, can form a meandering section, within which one of the plurality of battery cells can be arranged. The compression structure can extend only through the cooling plates or it can extend through the connecting element. This meandering cooling structure provides a simple construction, effective cooling, and the desired deformation characteristics due to the compression structure.

[0061] According to one embodiment, the cooling structure further includes a fluid inlet element disposed at a first end of the cell stack and a fluid outlet element disposed at a second end of the cell stack. The cooling structure can be configured to allow coolant to flow from the fluid inlet element through a cooling chamber of the cooling plate and out of the fluid outlet element. This embodiment can be adapted to the meandering cooling structure described above, wherein the cooling structure can be configured to allow coolant to flow from the fluid inlet element through a cooling chamber of the cooling plate, through a connecting element, and out of the fluid outlet element. Therefore, the coolant can flow continuously through the cooling plates. In other words, a single coolant flow is achieved across the entire cell stack. In another embodiment, the cooling structure may include a distribution channel extending along the stacking direction on the end face of the cell and connected to each cooling plate, allowing coolant to flow parallel across the cooling plates. The outermost cooling plate among the plurality of cooling plates may include a fluid inlet and / or a fluid outlet. For example, a first outermost cooling plate at the first end of the cell stack may form a fluid inlet element and / or a second outermost cooling plate at the second end of the cell stack may form a fluid outlet element. This design of the cooling structure provides a simple design as well as effective cooling and deformation performance.

[0062] As described above, the monolithic stack frame may include end plates that apply pressure to the monolithic stack. According to one embodiment, the end plate is shaped correspondingly to the adjacent side of the outermost cooling plate at its inner side facing the outermost cooling plate. For example, the end plate may be shaped correspondingly to the adjacent side of a cooling plate that includes a fluid inlet or outlet. "Correspondingly" can mean that the inner side of the end plate has a shape corresponding to the shape of the outer surface of the outermost cooling plate, allowing full surface contact between the end plate and the outermost cooling plate. The end plate may include through-holes configured to receive a fluid inlet or outlet, such that the fluid inlet or outlet can extend through the end plate. The end plate, shaped correspondingly to the cooling plate, allows for the efficient transfer of compressive force or pressure from the end plate to the outermost cooling plate and thus to the monolithic stack.

[0063] According to the embodiment, the cooling plate is an extruded plate. That is, the cooling plate including the compression structure can be formed by an extrusion process. The entire cooling structure can be formed by an extrusion process. The cooling plate including the compression structure or the entire cooling structure can be made of aluminum. For example, when the cooling plate is formed by an extrusion process, the cooling plate or the entire cooling structure can be formed by extruding aluminum. It is particularly simple and efficient to manufacture the cooling plate or the entire cooling structure including the cooling plate and connecting elements (if present) as an extruded profile. Elements of the compression structure, such as cooling elements that form cooling channels in the cooling chamber, can be formed in a structurally simple manner by extrusion. Moreover, such an extruded profile provides a stable structure while requiring a relatively small amount of material. Furthermore, the cooling plate and the compression structure therein can be formed in a single production step.

[0064] According to an embodiment, the compression structure includes a plurality of support frames distributed on the inner surfaces of two plate elements and extending between the two plate elements. The support frames or partition walls can separate the interior of the cooling plate, thereby forming cooling channels within the cooling chamber. The support frames extend from a first plate element of the two plate elements of the cooling plate to a second plate element of the two plate elements of the cooling plate. Therefore, the support frames transmit compressive force between the plate elements or through the cooling plate. The support frames can form cooling elements, i.e., smaller entities within the compression structure, which can be uniformly distributed across the entire cooling plate. The support frames or cooling elements can be deformable. That is, the support frames or cooling elements can have a shape or form that provides the aforementioned plastic deformability of the compression structure and thus the aforementioned plastic deformability of the cooling plate in a simple and effective manner. Various designs of the support frames or cooling elements are possible.

[0065] For example, according to an embodiment, the compression structure includes one or more of the following: a compression element with a rectangular cross-section, a compression element with a bottleneck-shaped cross-section, a compression element with a semi-circular cross-section, a compression element with a tent-shaped cross-section, a compression element with a rhomboid cross-section, and a compression element with a rhomboid cross-section having rounded ends. The support frame can be arranged such that compression elements of these shapes are formed. Compression elements with such cross-sections can allow the desired plastic deformation of the compression structure in a simple manner.

[0066] This disclosure also provides an electric vehicle that includes a battery system according to an embodiment of this disclosure, such as the battery system described above.

[0067] Figures 1 to 3 A battery system 100 according to an embodiment of the present disclosure is shown. The battery system 100 includes a plurality of prismatic battery cells 12 stacked along a stacking direction S to form a cell stack 10. In other embodiments, the battery cells 12 may be, for example, pouch-type battery cells. Each battery cell 12 may have cell terminals 14 for electrical interconnection on its top side (or top) and venting openings 13 for allowing gas and particles to exit the respective battery cell 12 during thermal runaway.

[0068] The battery system 100 also includes a cell stacking frame 20 for accommodating a cell stack 10. The cell stacking frame 20 includes sidewall elements 22 disposed parallel to the stacking direction S, a first end plate 24a disposed at a first end of the cell stack 10, and a second end plate 24b disposed at a second end of the cell stack 10. The end plates 24a and 24b apply pressure to the cell stack 10 along the axis of the stacking direction S to compress the cell stack 10.

[0069] Furthermore, the battery system 100 includes a cooling structure 40, which comprises a plurality of cooling plates 42 respectively arranged between adjacent battery cells 12. For example, the battery cells 12 and the cooling plates 42 are arranged alternately. The cooling structure 40 also includes a curved connecting element 44 that extends around (or around) the lateral end of the battery cell 12 and interconnects adjacent cooling plates 42, such that the cooling structure 40 has a meandering form. In other words, the cooling structure 40 includes a plurality of meanders, each of which is formed by two cooling plates 42 and a connecting element 44 connecting the two cooling plates 42 together. One of the battery cells 12 is located inside each meander of the cooling structure 40.

[0070] The cooling structure 40 also includes a fluid inlet element (e.g., a fluid inlet) 46 disposed at a first end of the monomer stack 10 and a fluid outlet element (e.g., a fluid outlet) 47 disposed at a second end of the monomer stack 10. Figure 3 A battery system 100 without the first end plate 24a is shown to illustrate a fluid inlet element 46. As shown, the fluid inlet element 46 is plate-shaped and includes a spacer portion (e.g., a protrusion) 46a that fills the gap between the outermost battery cell 12 and the first end plate 24a. The fluid outlet element 47 may also include a corresponding spacer portion 47a. The first end plate 24a is shaped on its inner side facing the fluid inlet element 46 corresponding to the adjacent side of the fluid inlet element 46, which can be understood as forming the outermost cooling plate. That is, the first end plate 24a flatly abuts the fluid inlet element 46 to provide full contact over the entire surface area of ​​the fluid inlet element 46, which improves the transmission of compressive force / pressure to the fluid inlet element 46. The first end plate 24a includes a through-hole 25 through which the inlet 46b of the fluid inlet element 46 extends. Similarly, the second end plate 24b may include a through-hole through which the outlet of the fluid outlet element 47 extends.

[0071] Each of the cooling plates 42 includes two plate elements 42a and 42b, through which a cooling chamber 48 for coolant flow is formed (see example). Figure 5The cooling structure 40 is configured to allow coolant to flow from a fluid inlet element 46 through a cooling chamber 48 formed within the cooling plate 42 and through a connecting element 44, and out through a fluid outlet element 47. The coolant flow can be reversed; that is, the fluid inlet element 46 can instead be a fluid outlet element, and the fluid outlet element 47 can instead be a fluid inlet element. Therefore, during normal operation of the battery system 100, coolant can flow through the meandering cooling structure 40, thereby cooling the battery cells 12 as they transfer heat to the cooling plate 42. Thus, the cooling plate 42 can be in substantially full-surface contact with adjacent battery cells 12, thereby facilitating heat transfer.

[0072] According to embodiments of this disclosure, each cooling plate 42 further includes a compression structure 50 disposed within the cooling chamber 48. (See also...) Figure 5 It shows along Figure 4 The compression structure 50, with a cross-section taken by line AA passing through one of the cooling plates 42, includes a plurality of support frames 52 distributed on the inner surfaces of the two plate elements 42a, 42b and extending between the two plate elements 42a, 42b. Figure 5 As can be seen, the support frame 52 is arranged in a repeating pattern along the cooling plate 42, wherein the elements of the pattern are referred to herein as compression elements 54. For example, the cooling structure 50 includes a plurality of compression elements 54 made of the support frame 52.

[0073] exist Figure 5 In the illustrated embodiment, the compression element 54 includes two support frames 52 extending vertically from plate element 42a and one support frame 52 extending vertically from plate element 42b. The three support frames 52 are interconnected by another support frame 52 extending parallel to plate elements 42a and 42b. The support frames 52 form cooling channels through which coolant can flow through the cooling chamber 48. That is, the compression structure 50 does not impede the flow of coolant through the cooling chamber 48.

[0074] The compression structure 50 is designed to plastically deform in response to compressive forces acting on the plate elements 42a, 42b of the cooling plate 42. For example, the compression element 54, due to its support frame 52, is deformable under compressive or compressive forces. Figure 5 (b) and Figure 5 (c) is indicated by a dashed arrow. Figure 5 In (a), the cooling plate 42 is shown in an uncompressed state. It can be seen that the support frame 52 forms a channel with a rectangular cross-section in the uncompressed state. Figure 5In (b), the cooling plate 42 is shown in a state where a first compressive force acts on the cooling plate 42, compressing the cooling plate 42, as indicated by the dashed arrow, which causes deformation of the compression element 54. For example, in a non-compressed state extending parallel to the plate elements 42a, 42b (see, for example) Figure 5 (a) The support frame 52 deforms and presses against the plate element 42a. Therefore, the thickness t of the cooling plate 42 decreases. Figure 5 In (c), the cooling plate 42 is shown in a state where a second compressive force acts on the cooling plate 42, which is higher than the first compressive force. Therefore, the cooling plate 42 is further compressed, such that in the uncompressed state (see example...), Figure 5 (a) The support frame 52, extending parallel to the plate elements 42a and 42b, deforms so that it contacts the inner surface of the plate element 42a. As a result, the thickness t of the cooling plate 42 further decreases. The support frame 52 can be plastically deformed up to this degree of compression.

[0075] Figure 5 The compression structure 50 shown is merely one embodiment, and this disclosure is not limited thereto. Figures 6 to 8 Another implementation is shown in the figure.

[0076] exist Figure 6 In the middle, the compression element 654 is formed as similar to Figure 5 The compression element 54 is shown, but not interconnected. For example, in the uncompressed state (see example...) Figure 6 (a) The support frame 652 extending parallel to the plate elements 42a and 42b does not form a single support frame for all compression elements 654. The deformation of the compression element 654 is similar to... Figure 5 The deformation of the compression element 54 shown is as follows: Figure 6 (a) to Figure 6 As shown in (c). Figure 6 (a) shows the cooling plate 42 in an uncompressed state. Figure 6 (b) shows the cooling plate 42 in a first compressed state. Figure 6 (c) shows the cooling plate 42 in a second, further compressed state. As shown, the thickness t of the cooling plate 42 decreases as the cooling plate 42 is compressed. The support frame 652 can be plastically deformed up to this degree of compression.

[0077] exist Figure 7 In the middle, the compression element 754 has a bottleneck-shaped cross-section formed by the support frame 752. Figure 7 (a) shows the cooling plate 42 in an uncompressed state. Figure 7 (b) shows the cooling plate 42 in a first compressed state. Figure 7(c) shows the cooling plate 42 in a second, further compressed state. As shown, the thickness t of the cooling plate 42 decreases as the cooling plate 42 is compressed. The support frame 752 can be plastically deformed up to this degree of compression.

[0078] exist Figure 8 In the middle, the compression element 854 has a semi-circular cross-section formed by the support frame 852. Figure 8 (a) shows the cooling plate 42 in an uncompressed state. Figure 8 (b) shows the cooling plate 42 in a first compressed state. Figure 8 (c) shows the cooling plate 42 in a second, further compressed state. As shown, the thickness t of the cooling plate 42 decreases as the cooling plate 42 is compressed. The support frame 852 can be plastically deformed up to this degree of compression.

[0079] exist Figure 9 In the middle, the compression element 954 has a tent-shaped cross-section formed by the support frame 952. Figure 9 The cooling plate 42 in an uncompressed state is shown. Similar to the embodiment described above, the thickness t of the cooling plate 42 decreases as it is compressed. Figure 9 In the embodiment shown, the support frame 952 is plastically deformed until the intermediate support frame 952a extending from the plate element 42a contacts the opposing plate element 42b, and the side support frame 952b extending from the plate element 42b contacts the opposing plate element 42a.

[0080] exist Figure 10 In the middle, the compression element 1054 has a rhomboid cross-section formed by the support frame 1052. Figure 10 The cooling plate 42 in an uncompressed state is shown. Similar to the embodiment described above, the thickness t of the cooling plate 42 decreases as the cooling plate 42 is compressed. The support frame 1052 undergoes plastic deformation until the intermediate support frames 1052a extending from each of the plate elements 42a, 42b contact each other and / or until the side support frames 1052b contact the corresponding plate elements 42a, 42b closest to them.

[0081] exist Figure 11 In the middle, the compression element 1154 has a rhomboid cross-section with a circular end 1152c formed by the support frame 1152. Figure 11 The cooling plate 42 in an uncompressed state is shown. Similar to the embodiment described above, the thickness t of the cooling plate 42 decreases as the cooling plate 42 is compressed. The support frame 1152 plastically deforms until the intermediate support frame 1152a extending from each plate element 42a, 42b contacts each other and / or until the side support frames 1152b contact the nearest corresponding plate elements 42a, 42b and / or until the rounded end 1152c contacts the plate elements 42a, 42b.

[0082] In each of the above embodiments, the compression structure 50 is designed such that it plastically deforms when receiving compressive forces acting on the plate elements 42a, 42b of the cooling plate 42. That is, the compression structure 50—and therefore the cooling plate 42—is plastically deformable, at least within the operating pressure range of the battery cell. For example, the cooling plate has plastic deformation characteristics due to the compression structure, such as constant or substantially constant plastic deformation characteristics. This is in Figure 13 As shown in the figure. The cooling structure 40, including the cooling plate 42, connecting element 44, and the compression structure inside the cooling plate 42, can be formed by extrusion and can be, for example, an aluminum extrusion profile. Within the designed range of compression / plastic deformation, the compression structure 50 does not allow direct load transfer between the plate elements 42a, 42b until the support frame contacts the corresponding opposing plate elements 42a, 42b.

[0083] Typically, as described above, the battery cells 12 of the cell stack 10 receive preload through end plates 24a, 24b. Therefore, the battery cells 12 are under operating pressure, which should be kept within a predetermined range depending on, for example, the type, size, and geometry of the battery cells 12, to ensure the intended operation of the battery cells 12. However, during their lifespan, the battery cells 12 may expand due to aging effects, which in conventional battery system designs can increase the pressure within the cell stack. However, using the battery system 100 according to an embodiment of this disclosure, this expansion of the battery cells 12 is at least partially compensated for by a plastically deformable compression structure 50. That is, as the battery cells 12 expand and thus increase in thickness, the cooling plate 42 is compressed and thus decreases in thickness.

[0084] During this compression, the cooling plate 42 does not apply increased pressure to the battery cells (unlike conventional cell separators with progressive deformation characteristics), but rather applies essentially the same pressure throughout the compression range, such as... Figure 13 As shown. In other words, the compression structure 50 is configured to avoid direct load transfer between plate elements 42a and 42b within the designed compression / plastic deformation range.

[0085] Figure 13This is a graph showing the ratio of force F to elongation (e.g., displacement) s of the cooling plate 42, including the compression structure 50. As shown, the applied force F increases linearly with the elongation s of the battery cell 12 (and therefore the stack length L) in the first section at a lower force (e.g., elastic deformation), and remains substantially constant or increases only slightly linearly with a higher force in the second section (e.g., plastic deformation). Even when the battery cell 12 expands due to aging, the compressive force (and therefore the pressure) remains within the window or range of ideal pre-compression of the cell stack. Furthermore, the applied force F gradually increases with even greater elongation s. That is, while the compression structure 50 may not allow direct load transfer between the plate elements 42a, 42b within the designed compression / plastic deformation range, when the cooling structure 40 is compressed beyond its expected deformation (e.g., most or all of the supports 52, 752, 852 begin to directly contact or abut the two cooling plates 42), the load path of the compressive force is drastically altered. Then, the compressive force F can travel almost straight from one side to the other, that is, from one plate element 42a to another plate element 42b, which causes the compression structure 50 to stiffen and prevents the cooling channels inside the cooling structure 40 from completely collapsing even if a larger expansion force / displacement than designed or expected occurs.

[0086] Therefore, due to the cooling plate 42 with its internal compression structure 50, the end plates 24a, 24b can apply a constant or substantially constant compressive force to the cell stack 10. This effectively compensates for manufacturing tolerances of the cell 12 and expansion forces / displacements during the lifespan of the battery system 100 without increasing pressure. The compression structure 50 is designed such that the minimum-maximum cell stack tolerance remains in a flat plateau region of the force / deflection curve, such as... Figure 13 As shown. This flat platform can be provided by the plastic deformation of the compression structure 50 of the cooling plate 42. Therefore, the monolithic stack 10 can be maintained within the optimal pressure range to achieve peak performance, thereby ensuring reliable and safe operation throughout its entire lifespan until the end of its service life.

[0087] Figure 12A battery system 100' according to another embodiment of the present disclosure is shown. In the battery system 100', the cooling structure 40' does not have a meandering form. That is, the cooling structure 40' does not include connecting elements for interconnecting the cooling plates 42', but can supply coolant to the cooling plates 42' in different ways. For example, a separate coolant supply line may be provided, extending through one of the sidewall elements 22' and connecting to the cooling plate 42', and / or a separate coolant discharge line may be provided, extending through the other sidewall element 22' and connecting to the cooling plate 42'. In another embodiment, a common supply line may be provided, extending parallel to the stacking direction S along the end side of the battery cell 12' and connecting to all cooling plates 42' at a first end of the cooling plate 42', and / or a common discharge line may be provided, extending parallel to the stacking direction S along the other end side of the battery cell 12' and connecting to all cooling plates 42' at a second end of the cooling plate 42'.

[0088] Some figure labels

[0089] 10 Single-unit stack

[0090] 12 battery cells

[0091] 13 Exhaust opening

[0092] 14 Individual Terminals

[0093] 20 Single-unit stacked frames

[0094] 22 Sidewall Components

[0095] 24a First end plate

[0096] 24b Second end plate

[0097] 25 through hole

[0098] 40 Cooling Structure

[0099] 42 Cooling plate

[0100] 42a Board Components

[0101] 42b board components

[0102] 44 Connecting elements

[0103] 46 Fluid inlet element

[0104] 46a Interval section

[0105] 46b entrance

[0106] 47 Fluid outlet element

[0107] 47a Interval section

[0108] 48 Cooling Chamber

[0109] 50 Compression Structure

[0110] 52 Support frame

[0111] 54 Compression element

[0112] 100 Battery System

[0113] 652 Support Frame

[0114] 654 Compression Element

[0115] 752 support frame

[0116] 754 Compression Element

[0117] 852 support frame

[0118] 854 Compression Element

[0119] 952 support frame

[0120] 952a support frame

[0121] 952b support frame

[0122] 954 Compression Element

[0123] 1052 Support Frame

[0124] 1052a support frame

[0125] 1052b support frame

[0126] 1054 Compression Element

[0127] 1152 Support Frame

[0128] 1152a Support Frame

[0129] 1152b support frame

[0130] 1152c Round end

[0131] 1154 Compression element

[0132] S stacking direction

Claims

1. A battery system, comprising: Multiple battery cells are arranged in a stack; A single-unit stack frame that accommodates the single-unit stack and applies pressure to the single-unit stack; as well as A cooling structure includes multiple cooling plates, each of which is arranged between adjacent battery cells in the battery cell, and each cooling plate includes: Two plate elements with a cooling chamber between them for coolant to flow through; as well as A compression structure disposed inside the cooling chamber is configured such that it plastically deforms in response to a compressive force acting on the plate element of the cooling plate.

2. The battery system according to claim 1, wherein, The cooling structure also includes a curved connecting element that extends around the end side of the battery cell and interconnects adjacent cooling plates among the plurality of cooling plates, giving the cooling structure a meandering form.

3. The battery system according to claim 1, wherein, The monolithic stack frame includes end plates that apply pressure to the monolithic stack.

4. The battery system according to claim 3, wherein, The end plate is formed on its inner side facing the outermost cooling plate, corresponding to the adjacent side of the outermost cooling plate.

5. The battery system according to claim 1, wherein, The cooling structure further includes a fluid inlet element disposed at a first end of the monomer stack and a fluid outlet element disposed at a second end of the monomer stack, and The cooling structure is configured to allow the coolant to flow from the fluid inlet element through the cooling chamber of the cooling plate and out of the fluid outlet element.

6. The battery system according to claim 1, wherein, The cooling plate is an extruded plate.

7. The battery system according to claim 1, wherein, The cooling plate is made of aluminum.

8. The battery system according to claim 1, wherein, The compression structure includes a plurality of support frames distributed on the inner surfaces of the two plate elements and extending between the two plate elements.

9. The battery system according to claim 1, wherein, The compression structure includes a compression element.

10. The battery system according to claim 9, wherein, The compression element has a rectangular cross-section.

11. The battery system according to claim 9, wherein, The compression element has a bottleneck-shaped cross-section.

12. The battery system according to claim 9, wherein, The compression element has a semi-circular cross-section.

13. The battery system according to claim 9, wherein, The compression element has a tent-shaped cross-section.

14. The battery system according to claim 9, wherein, The compression element has a rhomboid cross-section.

15. The battery system according to claim 9, wherein, The compression element has a rhomboid cross-section with a circular end.

16. An electric vehicle comprising a battery system according to any one of claims 1 to 15.

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