Battery system, electric vehicle and cooling plate

Abstract

A battery system, an electric vehicle, and a cooling plate are provided. The battery system includes: a plurality of battery cells stacked along a stacking direction; and at least one cooling plate disposed along the stacking direction between two adjacent battery cells among the plurality of battery cells, wherein the at least one cooling plate includes a chamber for coolant, the chamber having a deformable structure configured to transmit compressive forces along the stacking direction between opposite sides of the at least one cooling plate facing adjacent battery cells, and wherein the deformable structure is configured to equalize the compressive forces caused by length deviations of the plurality of battery cells along the stacking direction by deforming at least a portion of the deformable structure with a substantially constant force within a given displacement.

Description

Technical Field

[0001] This disclosure relates to a battery system, an electric vehicle including the battery system, and a cooling plate for the battery system. Background Technology

[0002] Recently, vehicles for transporting goods and people have been developed that use electricity as a power source. These electric vehicles are propelled continuously or temporarily by electric motors that utilize energy stored in rechargeable batteries. Electric vehicles can be powered solely by batteries (battery electric vehicles, BEVs) or can include a combination of an electric motor and, for example, a conventional internal combustion engine (plug-in hybrid electric vehicles, PHEVs). Both BEVs and PHEVs use high-capacity rechargeable batteries designed to provide propulsion power for a continuous 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 positioned 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 located within a housing, while electrode terminals that establish a conductive connection with the electrodes are located outside the housing. The housing can be, for example, cylindrical or rectangular in shape.

[0004] A battery module is formed by connecting multiple battery cells in series or parallel. In other words, a battery module is formed by interconnecting the electrode terminals of multiple battery cells according to the required power to achieve a 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 battery management system, and its cells are arranged within a housing. 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 vehicle applications, battery systems typically comprise multiple battery modules connected in series to provide a desired voltage.

[0006] A battery pack is any number (e.g., identical) of battery modules or individual battery cells. Battery modules (and corresponding battery cells) can be configured in series, parallel, or a combination of both to produce a 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 a battery pack requires appropriate mechanical connections, such as between the various components of the battery module and between them and the vehicle's supporting structure. These connections must remain functional and safe throughout the average lifespan of the battery system. Furthermore, installation space and interchangeability requirements must 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 the individual battery cells or battery module can be achieved through mating recesses in the frame or through mechanical interconnects such as bolts or screws. In other embodiments, the battery module is confined by fastening side plates to the sides of the carrier frame. Furthermore, 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. Where the battery pack should 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] According to existing battery systems, despite any modular structure, they typically include a battery casing that serves as an enclosure to seal the battery system relative to the environment and provide structural protection for the battery system components. Encapsulated battery systems are usually installed as a whole in their application environment, such as in electric vehicles. Therefore, replacing a defective system component (e.g., a defective battery sub-module) first requires disassembling the entire battery system and removing its casing. Even defects in small and / or inexpensive system components can lead to the disassembly and replacement of the entire battery system and its individual repairs. This procedure proves cumbersome due to the high cost, size, and weight of high-capacity battery systems, and the storage of large-volume battery systems (e.g., in a mechanic's workshop) becomes difficult.

[0011] Conventional battery systems include coolers on top of or below the cells and thermal barriers (so-called cell spacers) between the cells to regulate excess heat generated during charging or discharging. Such an arrangement is expensive but achieves good cooling and heat transfer characteristics. However, the (inevitable) thickness tolerances of the cell spacers and the cells themselves cause drastic variations in prestress on the cell stack, which can lead to poor battery system performance. To address the drawbacks caused by varying prestress in the cell stack, costly space- and / or time-consuming measures are required in mass production for compensating for length deviations in the cell stack.

[0012] Therefore, the purpose of this disclosure is to provide a battery system with good cooling and heat transfer characteristics at low cost. Summary of the Invention

[0013] The embodiment includes a battery system comprising: a plurality of battery cells stacked along a stacking direction; and at least one cooling plate disposed along the stacking direction between two adjacent battery cells of the plurality of battery cells, wherein the at least one cooling plate includes a chamber for coolant, the chamber having a deformable structure configured to transmit compressive forces along the stacking direction between opposite sides of the at least one cooling plate facing adjacent battery cells, and wherein the deformable structure is configured to equalize the compressive forces caused by length deviations of the plurality of battery cells along the stacking direction by deforming at least a portion of the deformable structure with a substantially constant force within a given displacement.

[0014] The deformable structure can be configured to deform at least 2.5% and at most 10% of the length of a single cell along the stacking direction with a substantially constant force within a given displacement.

[0015] The chamber may include multiple chambers, wherein at least one cooling plate may include multiple chambers uniformly distributed between opposite sides of the at least one cooling plate along a first direction perpendicular to the stacking direction.

[0016] The battery system may also include: a coolant collector including a channel extending along the stacking direction for conducting cooling fluid; and an annular groove for receiving an end portion of at least one cooling plate and a channel for connecting a chamber of at least one cooling plate to the coolant collector.

[0017] The battery system also includes at least one coolant collector extending along the stacking direction, the at least one coolant collector being fluidly connected to a chamber of at least one cooling plate.

[0018] At least one coolant collector may include: a channel extending along the stacking direction for conducting cooling fluid; and an annular groove for receiving an end portion of at least one cooling plate and for connecting the chamber of at least one cooling plate to the channel of the coolant collector.

[0019] At least one end portion of a cooling plate may be accommodated in an annular groove of a coolant collector, and the annular groove may be filled with a sealing material for sealing the fluid connection between the chamber of at least one cooling plate and the channel of the coolant collector.

[0020] The stiffness of at least one cooling plate at its end portion may be higher than the stiffness of at least one cooling plate at the portion positioned between adjacent battery cells.

[0021] The coolant collector may include fastening elements disposed on the lower and / or upper ridges of the coolant collector, the fastening elements being configured to connect to the frame and / or top cover of the battery system.

[0022] The fastening element can be located above and / or below the annular groove of the coolant collector.

[0023] The fastening element may include a hole connected to the annular groove for injecting sealing material into the annular groove.

[0024] The battery system may also include a frame having at least one hollow frame profile, wherein a coolant collector is located inside the at least one hollow frame profile and is connected to at least one cooling plate through an opening in the wall of the at least one hollow frame profile.

[0025] The battery system may also include opposing end plates arranged such that multiple battery cells are surrounded between the end plates along the stacking direction, wherein at least one coolant collector is mechanically attached to the end plate in a load-bearing manner.

[0026] The battery system may also include a plurality of additional battery cells stacked along a stacking direction adjacent to a plurality of battery cells, wherein end plates may surround both the plurality of battery cells and the plurality of additional battery cells along the stacking direction, and wherein the chambers of adjacent cooling plates may be fluidly connected to each other.

[0027] Electric vehicles include this battery system.

[0028] The embodiment includes a cooling plate for a battery system comprising a plurality of battery cells stacked along a stacking direction. The cooling plate includes a chamber for coolant and has a deformable structure configured to transmit compressive forces between opposite sides of the cooling plate. The deformable structure is further configured to equalize the compressive forces caused by length deviations of the stacked battery cells along the stacking direction by deforming at least a portion of the deformable structure with a substantially constant force within a given displacement.

[0029] The disclosure is defined by the appended claims. The following description is not limited thereto. Any disclosure outside the scope of the claims is intended for illustrative and comparative purposes only. Attached Figure Description

[0030] The features will become clear to those skilled in the art by referring to the detailed description of exemplary embodiments in the accompanying drawings, in which: Figure 1 A schematic diagram showing the propulsion force versus displacement characteristics of a stack of battery cells for comparison is shown; Figure 2 A schematic diagram illustrating the thrust versus displacement characteristics of a battery cell stack according to one or more embodiments of the present disclosure is shown. Figure 3 A schematic top view of a battery system according to one or more embodiments of the present disclosure is shown; Figure 4AA cross-sectional view of a cooling plate in an uncompressed state is shown according to one or more embodiments of the present disclosure; Figure 4B It shows Figure 4A A cross-sectional view of the cooling plate under partial compression. Figure 4C It shows Figure 4A A cross-sectional view of the cooling plate under full compression. Figure 5 A perspective view of the coolant collector of the battery system is shown; Figure 6 This illustrates an arrangement within a hollow frame profile according to one or more embodiments of the present disclosure. Figure 5 A perspective view of the coolant collector; and Figure 7 A schematic top view of a battery system according to one or more other embodiments of the present disclosure is shown. Detailed Implementation

[0031] Exemplary embodiments will now be described more fully below with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary practices to those skilled in the art.

[0032] In the accompanying drawings, the dimensions of layers and regions may be exaggerated for clarity. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, the layer or element may be directly on said other layer or substrate, or there may be intervening layers. Furthermore, it will be understood that when a layer is referred to as being "below" another layer, the layer may be directly below said other layer, or there may be one or more intervening layers. Additionally, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or there may be one or more intervening layers. The same reference numerals always refer to the same elements.

[0033] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. 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.

[0034] 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. 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 without modifying any individual element in the list.

[0035] It will also be understood that the terms “comprising,” “including,” or variations thereof indicate the presence of the stated attributes, areas, fixed quantities, steps, processes, elements, components, and combinations thereof, but do not exclude other attributes, areas, fixed quantities, steps, processes, elements, components, and combinations thereof.

[0036] 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, the membrane, region, or element may be directly on the other membrane, region, or element, or an intermediary membrane, intermediary region, or intermediary element may be present.

[0037] In this document, the terms "upper" and "lower" are defined according to the z-axis. For example, the upper cover is located at the upper part of the z-axis, while the lower cover is located at the lower part of the z-axis. In the accompanying drawings, the dimensions of the components may be exaggerated for clarity. For example, in the accompanying drawings, the dimensions or thickness of each component may be arbitrarily shown for illustrative purposes, and therefore the embodiments of this disclosure should not be construed as limited thereto.

[0038] 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 also be understood that, unless so explicitly defined herein, terms (such as those defined in a general dictionary) shall be interpreted as having the same meaning as they have in the relevant field and / or in the context of this specification, and not in an idealized or overly formal sense.

[0039] According to one or more embodiments of this disclosure, a battery system is provided. The battery system includes a plurality of battery cells stacked along a stacking direction and at least one cooling plate disposed between two adjacent battery cells arranged along the stacking direction. The cooling plate includes a chamber for coolant, the chamber having a deformable structure configured to transmit compressive forces along the stacking direction between opposite sides of the cooling plate facing adjacent battery cells. The deformable structure is configured to equalize the compressive forces caused by length deviations of the plurality of stacked battery cells along the stacking direction by deforming at least a portion of the deformable structure with a substantially constant force within a given displacement.

[0040] A conventional battery cell stack consists of battery cells and cell spacers characterized by a propulsion-to-displacement ratio due to material and conventional design properties. A drawback of this propulsion characteristic is its sensitivity to length or positional deviations, as small displacements can cause a sharp increase or decrease in the force applied to the cell stack, which can in turn significantly degrade the stack's performance. To mitigate these drawbacks, very tight and expensive manufacturing tolerances must be met, or other expensive and complex methods must be implemented during production to adjust the pre-tensioning and positioning of the cell stack.

[0041] Therefore, the overall idea of ​​this disclosure relies on the concept that an ideal stack of battery cells should have deformation characteristics that induce very similar compressive forces, regardless of length deviations in the stack of cells, such as those caused by manufacturing tolerances and / or expansion of the individual cells. In other words, it is desirable to deform with a substantially linear force-to-displacement ratio to maintain the high performance of the battery system.

[0042] A key aspect of this behavior lies in the internal structure of the cooling plate. The deformable structure may include a partition wall between two opposite sides of the cooling plate, which does not provide a direct load path for transmitting compressive forces. Instead, the partition wall of the deformable structure includes at least one deflection portion; that is, in the deflection portion, at least a portion of the partition wall of the deformable structure is deflected due to compressive forces acting along the stacking direction. In other words, a portion of the compressive force is used for the deflection of the deformable structure, thereby mitigating and / or compensating for the impact of propulsive forces on displacement performance. In other words, when compressive forces caused by length deviations along the stacking direction of multiple stacked battery cells act on the cooling plate, the deflection allows for a movement or displacement path of the cooling plate along the stacking direction.

[0043] In other words, if the cooling plate of this disclosure is compressed along the stacking direction within the operating pressure range of the battery cell, the compressive pressure remains constant or increases only slightly due to the plastic deformation of the deformable structure. Therefore, the deformable structure is configured to absorb the compressive force caused by the length deviations of the multiple stacked battery cells.

[0044] Advantageously, tolerances can be compensated for due to the plastic deformation of the cooling plate that compensates for the thickness of the battery cells, thereby enabling simplicity in production. Therefore, no (or at least minimal) length adjustments and / or pressure adjustments are required along the stacking direction, and the battery cell stack can be compressed and fixed to standard dimensions that will automatically induce the desired pressure range.

[0045] In other words, due to the plastic deformation of the cooling plate, the tolerances associated with variations in the net cell stack length (i.e., the length without the cooling plate) between cell stacks can be compensated to achieve the same total cell stack length (i.e., including the length of the cooling plate) for all cell stacks (or modules) of the battery pack under the same pressure. Although cell stacks may include different lengths along the stacking direction (e.g., due to manufacturing tolerances of the electrochemical active materials inside the cell casing), the plastic deformation characteristics of the cooling plate enable a balance of combined length and pressure.

[0046] Although a battery system with only one cooling plate has been described, a battery system may also include multiple cooling plates as described herein. For example, cooling plates may be arranged between every two adjacent cells in a stack of battery cells. However, cooling plates may be arranged only between some of the adjacent cells in a stack of battery cells.

[0047] According to one embodiment, the deformation structure can be configured to deform at least 2.5% and at most 10% of the length of a battery cell along the stacking direction with a substantially constant force within a given displacement. The deformation structure can be configured to deform at least 3.3% and / or at most 7.5% of the length of a battery cell along the stacking direction with a substantially constant force within a given displacement. The deformation structure can be configured to deform approximately 5% of the length of a battery cell along the stacking direction with a substantially constant force within a given displacement. Length deviation can refer to, for example, manufacturing tolerances and / or expansion of multiple stacked battery cells due to charging and discharging of the battery cells. The length of a battery cell can refer to the expected manufacturing length of the battery cell, i.e., without manufacturing tolerance. For example, the expected manufacturing length of a battery cell could be 30 mm, and the (corresponding) manufacturing tolerance could be ±0.5 mm. The deformation path of the deformation structure according to this example between 2.5% and 10% could therefore correspond to 0.75 mm to 3 mm.

[0048] Therefore, the deflection portion of the deformable structure can be configured to deflect 0.75 mm to 3 mm relative to the stacking direction. The length of a single battery cell can refer to the length of a single battery cell (e.g., the battery cell adjacent to the cooling plate within a battery cell stack). However, the length can also refer to the combined length of battery cells (i.e., the combined length of more than one battery cell), for example, two battery cells adjacent to the cooling plate in a battery cell stack, or any number of battery cells (e.g., each of the battery cells in a battery cell stack). In other words, the deformable structure can be configured to deform relative to two or more battery cells within the stated range along the stacking direction. In this case, the number of cooling plates can be reduced, thereby reducing the manufacturing and assembly costs of the battery system.

[0049] According to one or more other embodiments, the cooling plate may include (as described herein) a plurality of chambers for coolant, the chambers being uniformly distributed between opposite sides of the cooling plate along a first direction perpendicular to the stacking direction. For example, the first direction refers to the height direction of the battery cells. In other words, the chambers may be uniformly distributed along the height direction of the battery cells. In this case, the compressive pressure along the stacking direction can be distributed substantially uniformly between the battery cells, thereby preventing deformation of the battery cells and a corresponding reduction in their performance.

[0050] According to another embodiment, the battery system may further include at least one coolant collector extending along the stacking direction. The coolant collector may be fluidly connected to a chamber of a cooling plate. The coolant collector may be arranged adjacent to the battery cell stack, for example, in a direction perpendicular to both the height and stacking directions. In some embodiments, the battery system may include two coolant collectors extending along the stacking direction and fluidly connected to a chamber of a cooling plate. The coolant collectors may be arranged on opposite sides relative to a direction perpendicular to both the height and stacking directions. In other words, the coolant collectors may surround the battery cell stack along the stacking direction. The coolant collectors may be fluidly connected to the chambers of the cooling plate via opposite end portions of the cooling plate. For example, when using multiple cooling plates and / or cooling plates having multiple chambers, each of the chambers may be readily fluidly connected to the coolant collector(s). The coolant collector may be manufactured as a single piece and / or may be made of or composed of high-strength synthetic materials (such as fiber-reinforced plastics). The coolant collector may be formed by injection molding or a series of molding and joining operations (such as welding or gluing).

[0051] According to another embodiment, the battery system may further include two opposing end plates arranged such that a plurality of battery cells are surrounded between the two end plates along the stacking direction. A coolant collector may be mechanically coupled to the end plates in a load-bearing manner. In other words, the end plates and the coolant collector(s) may set a specified or predetermined length of the battery cell stack along the stacking direction, thereby causing compressive forces along the stacking direction due to length variations of the battery cells. For example, the coolant collector may serve as part of the housing or frame of the battery system. The coolant collector may include a latch with a locking element arranged at the end of the coolant collector for mechanical connection to the end plate. The locking element may be adapted to interlock with the end plate and / or maintain the position of the coolant collector(s) relative to the end plate. The end plates may be configured to provide a substantially uniform pressure distribution along the end surfaces of the battery cell stack along the stacking direction. The lateral end surfaces of the battery cell stack may be end surfaces arranged parallel to the opposite sides of the cooling plate facing adjacent battery cells. For example, end plates can be configured to provide a substantially uniform pressure distribution through a convex external shape relative to the stacking direction and a substantially flat internal shape that contacts the outermost battery cell of the battery cell stack. In other words, the middle portion of the end plate can extend further in the stacking direction and further away from the battery cell stack than the end portion of the end plate. Each of the end plates can be manufactured as a single piece and / or can be made of or composed of high-strength synthetic materials such as fiber-reinforced plastics.

[0052] According to another embodiment, the coolant collector(s) may include channels for conducting cooling fluid. The channels may extend along a stacking direction. The coolant collector may also include annular grooves for receiving end portions of cooling plates and for connecting the chambers of the cooling plates to the channels of the coolant collector. The annular grooves may be configured to receive end portions of cooling plates and / or connect the chambers of the cooling plates to the channels of the coolant collector. The annular grooves may extend along the height direction of the battery cell. In embodiments where multiple cooling plates are used, the coolant collector may include multiple annular grooves. For example, the coolant collector may include an annular groove for each cooling plate, corresponding respectively to the position of the cooling plates in the assembled state of the battery system. Thus, the end portion of each cooling plate may be received, and each chamber of the cooling plate may be fluidly connected to the channels of the coolant collector. The channels of the coolant collector may open to the outside of the coolant collector, for example, to a reservoir for coolant connected to the outside of the coolant collector.

[0053] According to another embodiment, the end portion of the cooling plate can be accommodated in an annular groove of the coolant collector, and the annular groove can be filled with a sealing material for sealing the fluid connection between the chamber of the cooling plate and the channel of the coolant collector. The sealing material may also have adhesive properties, thereby achieving long-term coolant sealing and mechanical cohesion of the battery system.

[0054] According to another embodiment, the stiffness of the cooling plate at its end portions can be higher than the stiffness at the portions positioned between adjacent battery cells. This increased stiffness prevents damage to the end portions of the cooling plate due to the sealing pressure of the sealing material. For example, the cooling plate may include inserts at the end portions configured to reinforce the cooling plate against the sealing pressure of the sealing material. Alternatively, the end portions of the cooling plate may be flattened to increase stiffness, or may be made of a harder material (e.g., a metal such as steel) compared to aluminum in the cooling plate. In other words, the cooling plate may have deformable intermediate portions for tolerance and expansion compensation of the battery cells, as well as rigid end portions, to provide the counter-pressure required for reliable long-term sealing.

[0055] According to another embodiment, the coolant collector may further include (a plurality of) fastening elements disposed at the lower and / or upper ridges of the coolant collector. The (a plurality of) fastening elements may be configured to connect to the frame and / or top cover of the battery system. Thus, mechanical loads from individual battery cells can be transferred to the battery pack frame and / or top cover via the (a plurality of) fastening elements of the coolant collector.

[0056] According to another embodiment, the fastening elements can be arranged above and / or below the recesses of the coolant collector. For example, the fastening elements can be arranged above and / or below each of the recesses in the coolant collector. The fastening elements can be arranged directly above and / or below the recesses of the coolant collector. Since the mechanical load from the battery cell is transferred to the coolant collector where the cooling plate meets the coolant collector, it is advantageous to minimize the distance between the force input (the cooling plate housed in the recess) and the force output (the fastening elements).

[0057] According to another embodiment, the fastening elements disposed above and / or below the recess of the coolant collector may include holes connected to the recess for injecting sealing material into the recess. The sealing material can then be easily disposed into the recess via the holes. For example, when both fastening elements disposed above and below the recess include holes, the sealing material can be applied from below into the hole of the lower fastening element, then rises to the top of the recess, covers all end portions of the cooling plate and the coolant collector along the recess, and excess sealing material exits the recess via the hole in the upper fastening element. Using holes in one or more fastening elements to introduce sealing material into the recess facilitates the application of the sealing material to ensure long-term coolant sealing and mechanical cohesion of the battery system.

[0058] According to another embodiment, the battery system further includes a frame having at least one hollow frame profile. A coolant collector may be disposed inside the hollow frame profile and connected to a cooling plate through an opening in the wall of the hollow frame profile. In the case of multiple cooling plates, an opening corresponding to each cooling plate may be included in the wall of the hollow frame profile. The housing of the coolant collector within the hollow frame profile can allow for clearer space in the battery system, thereby reducing its size and / or increasing the energy density of the battery system. In an embodiment, two hollow frame profiles are used to house two of the aforementioned coolant collectors.

[0059] According to another embodiment, the battery system further includes a plurality of additional battery cells (i.e., a second plurality of battery cells having substantially the same characteristics) stacked along the stacking direction and positioned adjacent to the plurality of battery cells. End plates can be configured to surround the plurality of battery cells along the stacking direction. In other words, the plurality of parallel battery cell stacks of the battery system can be compressed together along the stacking direction between a pair of common end plates, thereby compressing all battery cell stacks to the same length along the stacking direction with the same pressure. Differences caused by tolerances of the battery cells can be compensated for via cooling plates. Therefore, no performance degradation of the battery system due to deviations in battery cell length occurs. The chambers of adjacent cooling plates can be fluidly connected to each other to form a common fluid channel through the chambers of the cooling plates of adjacent battery cell stacks. The common fluid channel can be connected to coolant collectors(s).

[0060] Another embodiment of this disclosure relates to an electric vehicle including a battery system as disclosed herein. The features and advantages described with reference to the battery system above can be similarly applied to electric vehicles.

[0061] Another embodiment of this disclosure relates to a cooling plate for a battery system comprising a plurality of battery cells stacked along a stacking direction. The cooling plate may correspond to the cooling plate of the reference battery system described above. The cooling plate includes a chamber for coolant, the chamber having a deformable structure configured to transmit compressive forces between opposite sides of the cooling plate. The deformable structure is configured to equalize the compressive forces caused by length deviations of the stacked battery cells along the stacking direction by deforming at least a portion of the deformable structure with a substantially constant force within a given displacement. The features and advantages described with reference to the cooling plate of the above-described battery system can be similarly applied to a cooling plate for a battery system.

[0062] Figure 1 This is a schematic diagram illustrating the propulsion force versus displacement characteristics of a battery cell stack for comparison. A conventional battery cell stack comprises battery cells and cell spacers characterized by a propulsion force versus displacement ratio due to material and conventional design features. Because small displacements result in relatively abrupt increases or decreases in the force applied to the battery cell stack, this gradual characteristic is susceptible to length or positional deviations, which in turn significantly degrades the stack's performance. For example, the stiffness of a conventional battery cell stack is too high within the desired force range, making it impossible to maintain within that range using conventional methods and tolerances given existing technology. Figure 1 As exemplified in the example, compared to the stack length between "nominal" and "maximum", the stack length between "minimum" and "nominal" results in a relatively small increase in the force applied to the battery cell stack (see "minimum advance" to "nominal advance"), while the stack length between "nominal" and "maximum" results in a twofold increase in the force applied to the battery cell stack (see "nominal advance" to "maximum advance"). To mitigate these drawbacks, very tight and expensive manufacturing tolerances must be met, or other expensive and complex methods must be implemented during production to adjust the pre-tensioning positioning of the battery cell stack.

[0063] Figure 2 This is a schematic diagram illustrating the linear plastic (constant) force versus displacement characteristics of a battery cell stack within a favorable pressure range across the entire tolerance range of the cell stack, according to one or more embodiments. The battery cell stack includes deformation characteristics that result in very similar compressive forces, independent of variations in the cell stack length caused by manufacturing tolerances and / or bulging. Figure 2As shown, linear elasticity to displacement performance can be anticipated in the first segment with a relatively low stack length. Then, in the second segment where there may be stack length deviations in the battery cell stack, the pretension of the battery cell stack is maintained within the desired range (indicated by the rectangle). In other words, a linear plastic deformation curve is achieved that keeps the force at a level independent of possible length deviations in the battery cell stack caused by manufacturing tolerances and / or expansion. Since the linear plastic deformation curve is constant, the compressive force remains substantially the same, so that the pretension of the battery cell stack remains constant, independent of the length deviations in the battery cell stack. It should be noted that this disclosure is not limited to the strictly constant behavior of the linear plastic deformation curve. The linear plastic deformation curve can also be formed with a slightly increased or decreased slope, such that the pretension of the battery cell stack is maintained substantially within the desired range (indicated by the rectangle). A slight increase or decrease can refer to a range in which the maximum force is at most 2.5 times the minimum force. In the embodiment, the maximum force is at most twice the minimum force. Figure 2 As further shown, in the third section with a relatively high stack length, propulsion and deflection behavior take over to prevent complete folding of the coolant chambers in the cooler of the battery cell stack (e.g., Figure 4C (as shown in the image).

[0064] Figure 3 A top view shows a battery system 100 without a top cover. The battery system 100 includes a plurality of battery cells 10 stacked along a stacking direction S (i.e., relative to...). Figure 3 The image plane is horizontally oriented for the battery cell 10. The battery cell 10 is exemplarily shown as a prismatic battery cell 10. However, the battery cell 10 can also be of another type, such as a pouch type. Each of the plurality of battery cells 10 includes an exhaust valve 22 disposed between two electrode terminals 24 on the terminal side. The terminal side of the battery cell 10 is arranged orthogonally to the stacking direction S (e.g., the terminal side of the battery cell 10 faces the top direction (i.e., the height direction) of the battery system 100). Each of the exhaust valves 22 and the electrode terminals 24 are aligned with each other to form one row of exhaust valves 22 and two rows of electrode terminals 24 along the stacking direction S. The electrode terminals 24 are respectively disposed at opposite ends of the terminal side of the battery cell 10 relative to the lateral direction orthogonal to the stacking direction S and the height direction.

[0065] The battery system 100 also includes at least one cooling plate 12, which is arranged between two adjacent battery cells 10 along the stacking direction S of the plurality of battery cells 10. Figure 3As shown, except for the outermost battery cell 10, a cooling plate 12 is arranged next to every two battery cells 10. However, the cooling plate 12 can be arranged between each pair of adjacent battery cells 10. For example, the cooling plate 12 can be arranged at each second battery cell 10, each third battery cell 10, or each fourth battery cell 10. In one embodiment, the battery system 100 may include only one cooling plate 12 for multiple battery cells 10.

[0066] Each of the cooling plates 12 includes a chamber 14 for coolant (see...) Figure 4A The chamber 14 has a deformable structure 16 configured to transmit compressive forces along the stacking direction S between the opposing sides of the cooling plate 12 facing adjacent battery cells 10. However, at least one or more of the cooling plates 12 may include such a chamber 14. (See below for further details.) Figures 4A to 4C The internal structure of the cooling plate 12 and the deformable structure 16 are described in detail.

[0067] The battery system 100 also includes two coolant collectors 18 extending along the stacking direction S. The coolant collectors 18 are arranged relative to the lateral direction on opposite sides of the plurality of battery cells 10 and adjacent to the plurality of battery cells 10. In the assembled state of the battery system 100, the coolant collectors 18 are fluidly connected to the chamber 14 of each cooling plate 12. For reasons of understanding, the coolant collectors 18 are... Figure 3 The coolant collector 18 is shown as being spaced apart from multiple battery cells 10. The length of the coolant collector 18 exceeds the combined length of the multiple battery cells 10. In other words, the coolant collector 18 surrounds the multiple battery cells 10 along the stacking direction S. Figure 3 As shown, the cooling plate 12 extends further in the lateral direction than the plurality of battery cells 10. During assembly, the coolant collector 18 can be moved toward the plurality of battery cells 10 to accommodate the protruding end portions of the cooling plate 12. In the assembled state, the coolant collector 18 is fluidly connected to a chamber 14 of each of the cooling plates 12 via the protruding opposite end portions of the cooling plates 12. Each coolant collector 18 may include a channel 26 for conducting cooling fluid.

[0068] Channels 26 extend along the stacking direction S. Channels 26 are respectively connected to chambers 14 of the cooling plate 12. Each of the channels 26 leads to the exterior of a corresponding coolant collector 18, for example, to a reservoir for coolant connected to the exterior of the coolant collector 18. The coolant collectors 18 may all be made as a single piece and / or may all be made of or composed of high-strength synthetic materials (such as fiber-reinforced plastics). The coolant collectors 18 may all be formed by injection molding or a series of molding and joining operations (such as welding or gluing). However, the battery system 100 may include only one or more of the described coolant collectors 18.

[0069] like Figure 3 As further shown, the battery system 100 also includes two opposing end plates 20, arranged such that a plurality of battery cells 10 are surrounded between the two end plates 20 along the stacking direction S. In the assembled state, a coolant collector 18 is mechanically attached to the end plates 20 in a load-bearing manner. In other words, the end plates 20 and the coolant collector 18 can be set to a specified or predetermined length of the plurality of battery cells 10 along the stacking direction S, thereby causing compressive forces along the stacking direction S due to length deviations of the battery cells 10. For example, the coolant collector 18 can be used as part of the housing or frame of the battery system 100. The end plates 20 can be configured to provide a substantially uniform pressure distribution along the end faces of the plurality of battery cells 10 along the stacking direction S. For example, the end plates 20 can be configured to provide a substantially uniform pressure distribution through a profile convex relative to the stacking direction S and a substantially flat internal shape that contacts the outermost battery cell 10 of the plurality of battery cells 10. In other words, the middle portion of the end plates 20 can extend further away from the battery cells 10 along the stacking direction S than the end portions of the end plates 20. Each of the end plates may be made as a single piece and / or may be made of or composed of high-strength synthetic materials such as fiber-reinforced plastics.

[0070] To prevent performance loss due to compressive forces caused by length deviations of the battery cells 10, the deformation structure 16 of the cooling plate 12 is configured to withstand a substantially constant force (e.g., within a given displacement) through compression. Figure 2 As shown, at least a portion of the deformable structure 16 is deformed to equalize the compressive forces caused by length deviations of the multiple stacked battery cells 10 along the stacking direction S. Figures 4A to 4C The present disclosure shows a combination of, as shown in, Figure 2 The battery system 100 with the cooling plate 12 shown in the diagram is a possible embodiment. Figures 4A to 4C The diagram shows different compression conditions that result in different positions of the partition wall of the cooling plate 12.

[0071] Figure 4A This is a cross-sectional view of the cooling plate 12 in an uncompressed state according to an embodiment of the battery system 100. Figure 4B and Figure 4C The middle section shows the following: Figure 4A Cross-sectional views of the cooling plate 12 in partially compressed and fully compressed states.

[0072] like Figure 4A As shown, the cooling plate 12 includes a plurality of chambers 14 for coolant, the chambers 14 being arranged between opposite (main) sides of the cooling plate 12. The plurality of chambers 14 are uniformly distributed along the height direction of the battery cell 10. In this case, the compressive pressure along the stacking direction S can be substantially uniformly distributed between the regions of adjacent battery cells 10 in contact with the cooling plate 12, thereby reducing or preventing deformation of the battery cells 10, and thus preventing a corresponding decrease in the performance of the battery system 100.

[0073] The deformable structure 16 includes a plurality of partition walls between two opposite sides of the cooling plate 12 that do not provide a direct load path for transmitting compressive force. Instead, each partition wall of the deformable structure 16 includes at least one deflection portion, i.e., in which at least a portion of the partition wall of the deformable structure 16 is deflected due to the compressive force acting along the stacking direction S. In other words, a portion of the compressive force is used for the deflection of the deformable structure 16, thereby mitigating and / or compensating for the impact of propulsion on displacement performance. In other words, when the compressive force caused by the length deviation of the plurality of battery cells 10 along the stacking direction S acts on the cooling plate 12, the deflection allows the cooling plate 12 to have a movement path or displacement path along the stacking direction S.

[0074] like Figure 4A As shown, each chamber 14 is shaped as a cuboid, for example, extending along the cooling plate 12 between opposite end portions in the transverse direction of the cooling plate 12. The length of the chamber 14 in the stacking direction S is approximately half the length of the cooling plate 12 in the stacking direction S. The middle portion of each chamber 14 in the height direction is connected to one side of the opposite side of the cooling plate 12 via a connecting portion. The connecting portion provides a direct load path between the opposite side of the cooling plate 12 and the middle portion of the chamber 14.

[0075] When the cooling plate 12 of this disclosure is compressed along the stacking direction S within the operating pressure range of the battery cell 10, the compression pressure remains constant or increases linearly due to the plastic deformation of the deformable structure 16. Figure 4B As shown, the middle portion of chamber 14 is partially pressed into chamber 14 via a connecting portion. The corresponding partition wall of chamber 14 deflects, such that the deformable structure 16 is configured to absorb compressive forces caused by length deviations of the multiple battery cells 10. In the fully compressed state (see...), Figure 4CThe deflected partition wall of chamber 14 is compressed by the connecting portion, thereby contacting the other side of the opposite side of the cooling plate 12. In other words, the deflected partition wall contacts the side of the cooling plate 12 opposite to the connecting portion under full compression.

[0076] Advantageously, due to the plastic deformation of the deformable structure 16 of the cooling plate 12, the length tolerance of the battery cell 10 along the stacking direction S can be compensated, thereby achieving simplicity in production. Therefore, no (or at least less) length adjustment and / or pressure adjustment along the stacking direction S is required, and multiple battery cells 10 can be compressed and fixed in a standard size that will automatically generate the desired pressure (i.e., the desired pre-tension).

[0077] Reference Figure 5 and Figure 6 The structure of the coolant collector 18 will now be described in detail.

[0078] Figure 5 This is a perspective view of the coolant collector 18 of the battery system 100. (See image.) Figure 5 The illustrations in the figure best illustrate, with an enlarged view showing the end portion of the coolant collector 18, which includes a plurality of annular grooves 28. Each of the annular grooves 28 is configured to receive the end portion of a cooling plate 12 and connect the chamber 14 of the cooling plate 12 to the channel 26 of the coolant collector 18. In other words, the coolant collector 18 includes one annular groove 28 for each cooling plate 12 of the battery system 100. The annular grooves 28 are arranged to correspond to the position of the cooling plate 12 in the assembled state of the battery system 100. The annular grooves 28 extend along the height direction of the battery cell 10. Thus, the end portion of each cooling plate 12 can be received, and each of the chambers 14 of the cooling plate 12 can be fluidly connected to the channel 26 of the coolant collector 18.

[0079] like Figure 5 As further shown, at least one fastening element 30 is arranged above each of the annular grooves 28 of the coolant collector 18, and at least one fastening element 30 is arranged below each of the annular grooves 28 of the coolant collector 18. The fastening elements 30 are configured to mechanically connect the coolant collector 18 to the frame and / or top or top cover of the battery system 100. More specifically, the fastening elements 30 are arranged directly above and directly below the annular grooves 28 of the coolant collector 18. Since the mechanical load from the battery cell 10 is transferred to the coolant collector 18 where the cooling plate 12 meets the coolant collector 18, it is advantageous to minimize the distance between the force input (the cooling plate 12 housed in the annular groove 28) and the force output (the fastening element 30). However, other arrangements of the fastening elements 30 are possible.

[0080] Each of the fastening elements 30 includes a hole 32 connected to an annular groove 28 for injecting sealing material into the annular groove 28. The sealing material is readily arranged into the annular groove 28 via the hole 32. The sealing material can be applied from below into the hole 32 of the lower fastening element 30. The sealing material then rises to the top of the annular groove 28, covers the entire end portion of the cooling plate 12 and the coolant collector 18 along the annular groove 28, and excess sealing material exits the annular groove 28 via the hole 32 in the upper fastening element 30. Therefore, introducing the sealing material into the annular groove 28 via the hole 32 facilitates the application of the sealing material to ensure long-term coolant sealing and mechanical cohesion of the battery system 100.

[0081] Furthermore, the coolant collector 18 includes a latch 38 disposed at opposite ends of the coolant collector 18 relative to the stacking direction S, so that the coolant collector 18 is mechanically connected to the end plate 20. The latch 38 is adapted to interlock with the end plate 20 and maintain the position of the coolant collector 18 relative to the end plate 20.

[0082] Reference Figure 6 Another embodiment in which the battery system 100 also includes a frame having at least one hollow frame profile 34 is described. The hollow frame profile 34 is shown in perspective view as being located within the hollow frame profile 34. Figure 5 The coolant collector 18, located inside the hollow frame profile 34, can be connected to the cooling plate 12 through openings 36 in the wall of the hollow frame profile 34 facing the multiple battery cells 10. Figure 6 As shown, an opening 36 for each cooling plate 12 is included in the wall of the hollow frame profile 34. Each of the openings 36 can be shaped as a slit corresponding to the shape of the end portion of the cooling plate 12. For example, each of the coolant collectors 18 can be housed in a separate hollow frame profile 34. The housing of the coolant collectors 18 within the hollow frame profile 34 allows for clearer space in the battery system 100, enabling a reduction in its size and / or an increase in the energy density of the battery system 100. In an embodiment, two hollow frame profiles 34 are used to house... Figure 3 The battery system 100 has two coolant collectors 18. Therefore, the hollow frame profile 34 is arranged on opposite sides of the plurality of battery cells 10 in the lateral direction.

[0083] Figure 7 A schematic top view of a battery system 100 according to another embodiment is shown. In the following, descriptions of the features already described are omitted, and only the different features of this embodiment are explained in detail.

[0084] According to this embodiment, the battery system 100 also includes a plurality of battery cells 10' along the stacking direction S. The plurality of battery cells 10, as described with reference to the foregoing figures, can be considered as a first plurality of battery cells 10. Then, for example, the battery system 100 according to this embodiment may further include a second to a fourth plurality of battery cells 10' having substantially the same characteristics as the first plurality of battery cells 10. The first to fourth plurality of battery cells 10' can be considered as being arranged as a first to fourth stack of battery cells adjacent to each other in the lateral direction. The end plate 20 can be configured to surround each of the first to fourth plurality of battery cells 10' along the stacking direction S. In other words, the plurality of parallel battery cell stacks of the battery system 100 can be compressed together along the stacking direction S between a pair of common end plates 20 to compress all the battery cell stacks to the same length along the stacking direction S with the same pressure (simultaneously). Differences caused by tolerances of the battery cells 10, 10' can be compensated for via the cooling plate 12. Therefore, no performance degradation of the battery system 100 due to deviations in battery cell length occurs. The chambers 14 of adjacent cooling plates 12 can be fluidly connected to each other to form a common fluid channel through the chambers 14 of adjacent battery cell stacks. This common fluid channel can be connected to a coolant collector 18. In an embodiment, the coolant collector 18 can also be housed in a... Figure 6 The hollow frame profile shown.

[0085] Example embodiments have been disclosed herein, and although specific terminology has been used, they are used and interpreted in a general and descriptive sense only and not for limiting purposes. In some instances, as will be apparent to those skilled in the art upon filing this application, unless expressly indicated otherwise, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

[0086] Figure Labels 10, 10' battery cells 12 Cooling plates 14 chambers 16 Deformable Structures 18 Coolant Collector 20 end plate 22. Exhaust valve 24 Electrode Terminals 26 channels 28 Annular groove 30 Fastening elements 32 holes 34 Hollow Frame Profiles 36 Opening 38. Latch 100 Battery System S indicates the stacking direction.

Claims

1. A battery system, the battery system comprising: a plurality of battery cells stacked along a stacking direction; and at least one cooling plate arranged between two adjacent battery cells of the plurality of battery cells along the stacking direction, wherein the at least one cooling plate comprises a chamber for a cooling liquid, the chamber having a deformation structure configured to transfer a compression force along the stacking direction between opposite sides of the at least one cooling plate facing the adjacent battery cells, and wherein the deformation structure is configured to equalize a compression force caused by a length deviation of the plurality of battery cells along the stacking direction by deforming at least a portion of the deformation structure with a constant force within a given displacement. the deformation structure is configured to deform a length of a battery cell along the stacking direction by at least 2.5% and at most 10% with a constant force within a given displacement.

2. The battery system of claim 1, wherein, the chamber comprises a plurality of chambers, wherein the at least one cooling plate comprises the plurality of chambers uniformly distributed along a first direction perpendicular to the stacking direction between opposite sides of the at least one cooling plate.

3. The battery system of claim 1, wherein, 4. The battery system of claim 1, further comprising: a coolant collector comprising a channel for conducting a cooling fluid extending along the stacking direction, and an annular groove for accommodating an end portion of the at least one cooling plate and for connecting the chamber of the at least one cooling plate to the channel of the coolant collector. the chamber comprises a plurality of chambers, wherein the at least one cooling plate comprises the plurality of chambers uniformly distributed along a first direction perpendicular to the stacking direction between opposite sides of the at least one cooling plate.

5. The battery system of claim 4, wherein, 6. The battery system of claim 1, further comprising at least one coolant collector extending along the stacking direction, the at least one coolant collector being fluidically connected to the chamber of the at least one cooling plate. the at least one coolant collector comprises:

7. The battery system of claim 6, wherein, a channel extending along the stacking direction for conducting a cooling fluid; and an annular groove for accommodating an end portion of the at least one cooling plate and for connecting the chamber of the at least one cooling plate to the channel of the coolant collector. an end portion of the at least one cooling plate is accommodated in the annular groove of the coolant collector and the annular groove is filled with a sealing material for sealing a fluidic connection between the chamber of the at least one cooling plate and the channel of the coolant collector.

8. The battery system of claim 7, wherein, a stiffness of the at least one cooling plate at the end portion is higher than a stiffness of the at least one cooling plate at a portion of the at least one cooling plate placed between the adjacent battery cells.

9. The battery system of claim 8, wherein, the coolant collector comprises a snap-in element arranged at a lower ridge and / or an upper ridge of the coolant collector, the snap-in element being configured to be connectable to a frame and / or a top cover of the battery system.

10. The battery system of claim 4, wherein, ​ 11. The battery system of claim 7, wherein, The at least one coolant collector comprises a snap-in element at a lower ridge and / or an upper ridge of the coolant collector, the snap-in element being configured to be connectable to a frame and / or a top cover of the battery system.

12. The battery system of claim 11, wherein, The snap-in element is above and / or below the annular groove of the coolant collector.

13. The battery system of claim 12, wherein, The snap-in element comprises an aperture connected to the annular groove for injecting a sealing material into the annular groove.

14. The battery system of claim 4, further comprising a frame having at least one hollow frame profile, wherein, The coolant collector is connected to the at least one cooling plate inside the at least one hollow frame profile and through an opening in a wall of the at least one hollow frame profile.

15. The battery system of claim 6, further comprising a frame having at least one hollow frame profile, wherein, The coolant collector is connected to the at least one cooling plate inside the at least one hollow frame profile and through an opening in a wall of the at least one hollow frame profile.

16. The battery system of claim 6, further comprising opposing end plates arranged such that the plurality of battery cells are enclosed between the end plates along the stacking direction, wherein, The at least one coolant collector is mechanically bonded to the end plate in a load-bearing manner.

17. The battery system of claim 16, further comprising another plurality of battery cells stacked along the stacking direction immediately adjacent to the plurality of battery cells, wherein, The end plate encloses both the plurality of battery cells and the further plurality of battery cells along the stacking direction, and wherein the chambers of adjacent cooling plates are fluidly connected to each other.

18. An electric vehicle comprising the battery system according to any one of claims 1 to 17.

19. A cooling plate for a battery system comprising a plurality of battery cells stacked along a stacking direction, the cooling plate comprising: a chamber for a cooling liquid, the chamber having a deformation structure configured to transfer a compression force between opposite sides of the cooling plate, wherein the deformation structure is further configured to equalize a compression force caused by a length deviation of the stacked battery cells along the stacking direction by deforming at least a portion of the deformation structure with a constant force within a given displacement.

Images