Method for cooling battery cells to provide higher crash safety and cooling system

Abstract

A cooling system (10) for cooling a battery cell (12) for use in a motor vehicle includes a cooling device (28, 30, 50) and a battery cell (12). The battery cell includes a cell housing (14) and cell components (22, 24, 26) disposed within the cell housing (14). The cooling device (28, 30, 50) has at least one cooling channel (28) through which a cooling medium can flow. The cooling channel is configured to have channel walls (30, 50, 52, 14), which are at least partially configured to be flexible. Here, at least one cooling channel (28) through which a cooling medium can flow is at least partially disposed within the cell housing (14) and configured such that when the cooling channel (28) is circulated by a cooling medium having a specific cooling medium pressure, at least one flexible region (30, 52) of the channel wall (30, 50, 52, 14) presses against at least a portion of the cell components (22, 24, 26) due to the cooling medium pressure.

Description

Technical Field

[0001] This invention relates to a cooling system for cooling battery cells used in motor vehicles, particularly for providing enhanced crash safety. The cooling system includes a cooling device and battery cells, each battery cell comprising a cell housing and cell components disposed within the cell housing. The cooling device has at least one cooling channel through which a cooling medium can flow, the cooling channel having channel walls that are at least partially flexible. The invention also includes a method for cooling battery cells. Background Technology

[0002] Current cooling systems, for example, consist of aluminum plates with similar wall thicknesses. Multiple flow channels are formed within these plates. These channels all have the same cross-section but different lengths. Consequently, the cooling medium flows through each channel in different ways and is therefore unbalanced. Furthermore, a base plate is fixedly connected to the cooling plate. Consequently, this cooling system cools the cells only from below, limiting the cooling power. Additionally, to connect the cooling structure to the bottom of the cells, a gap filler, i.e., a thermally conductive material, is typically required, which adds to the cost and weight. Moreover, this cooling structure is unsuitable for high-voltage batteries in electric or hybrid vehicles, where higher charging currents (greater than 100 kW) are insufficient for the required cooling power.

[0003] Besides cooling systems using rigid cooling channels, the use of flexible cooling plates is also known from the prior art. For example, patent document DE 10 2017 210 343 A1 describes a cooling plate for a battery having a membrane into which a cooling medium can be introduced. This flexible cooling plate has membrane chambers that fluidically interconnect the system, and wherein a cooling medium inlet or outlet is in flow connection to the membrane chambers. The flexible cooling plate is movable through the membrane chambers and is elastic, and therefore can conform to the shape of the surface to be cooled (on which the cooling plate rests). For example, such a cooling plate can be arranged between battery modules of a battery, wherein the corresponding battery module can have multiple battery cells, especially pouch cells. Such pouch cells, for example, have a cell housing in the form of a pouch membrane, within which an electrode complex with outwardly extending negative electrode contacts is arranged.

[0004] Although cooling channels constructed with partial flexibility can improve cooling efficiency due to their compatibility with the surface to be cooled, further improvements in the efficiency of cooling devices used to cool individual battery cells are still desired.

[0005] Furthermore, another important aspect related to vehicle batteries, especially high-voltage batteries, is crash safety. In the event of a vehicle accident, if a battery cell is damaged, it may experience thermal runaway, which is often accompanied by a battery fire. Accordingly, it is desirable to minimize the risk of damage to battery cells in a collision. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a cooling system and a method that achieves cooling of at least one battery cell as effectively as possible, and further improves safety in relation to accidents.

[0007] This objective is achieved by a cooling system and method having the features described in the respective independent claims. The dependent claims, the specification, and the drawings represent advantageous embodiments of the invention.

[0008] The cooling system for cooling batteries for motor vehicles according to the present invention has a cooling device surrounding a battery cell, the cooling device comprising a cell housing and a cell component disposed within the cell housing, wherein the cooling device has at least one cooling channel through which a cooling medium can flow, the cooling channel having a channel wall, the channel wall being at least partially configured to be flexible. Here, the at least one cooling channel through which the cooling medium can flow is at least partially disposed within the cell housing and configured such that, when the cooling channel is circulated by a cooling medium having a specific cooling medium pressure, at least one flexible region of the channel wall presses against at least a portion of the cell component due to the cooling medium pressure.

[0009] Here, the invention is based on several understandings: on the one hand, heat is generated inside the battery cell during operation, specifically at the end of the cell core / cell wickel located within the cell, which can be, for example, part of the cell component arranged in the cell housing as described above. By integrating cooling channels into the interior of the battery cell, it is advantageously possible to purposefully cool the battery cell at the location of heat generation, i.e., inside the cell. This is achieved for the first time through channel walls that are at least partially flexibly constructed. This is based on the understanding that flexibly constructed channel walls are not only advantageously suited to conform to the geometry of the component to be cooled, but also provide particularly effective cooling in areas with very limited available structural space. Therefore, such cooling channels with flexibly constructed cooling walls can be very easily integrated into the battery cell in a state where no cooling medium flows through them, i.e., within the cell housing, and correspondingly, when the cooling channels are traversed by a cooling medium, they not only match the geometry of the components in their environment, especially the cell component to be cooled, but also optimally match the available free space within the cell. However, another significant advantage of the present invention is that, through this cooling system, collision safety can also be significantly improved in the event of an accident involving a vehicle equipped with such a cooling system. This is based on the understanding that the cooling channels can be actively expanded, for example, during or shortly before a collision, thereby reinforcing the cell housing and the entire cell group or battery module comprising multiple such cells. This reinforcement protects the cells themselves from intrusion. This makes it difficult for other objects to enter the cells, which in turn reduces the risk of cell damage, thereby significantly improving safety in collision situations due to the reduced risk of thermal runaway of the battery cells.

[0010] Accordingly, it is advantageous that the cooling device is configured to be actively controllable. Here, control can be achieved, for example, by a control device and, in particular, by controlling situational parameters, especially the flow of the cooling medium. These situational parameters may indicate, for example, the currently required cooling power or a predicted hazardous situation or impending collision. Thus, it provides particularly good situational matching, both for the required cooling power and for improving collision safety.

[0011] Within the scope of this invention, a battery cell is understood as the smallest structural unit of a battery for a motor vehicle, meaning that a battery cell does not have other individual cells and is not a group of cells. Such a battery, especially a high-voltage battery, may, for example, have multiple battery modules, each of which may further include multiple such battery cells. As described, a battery cell may include, for example, a cell core as a cell component. Furthermore, the cell component may also have two current collectors / absorbers, which are electrically connected to the corresponding cell terminals of the battery cell. Generally, a cell core is understood as an electrode composite structure, which does not necessarily have to be wound. The electrode contacts are guided outward to the cell terminals via the current collectors.

[0012] As a cooling medium, both liquid and gaseous cooling media can be used. Preferably, the cooling medium is a water-ethylene glycol mixture. However, heat transfer oils or other fluids are also conceivable. As a cooling medium, for example, a phase change material (PCM) can also be used. PCM is designed to absorb heat and undergo at least a partial phase transition above a defined phase transition temperature. The cooling medium may, for example, only partially comprise such a PCM. Furthermore, during the phase transition, such a PCM may exhibit, for example, a phase transition from solid to liquid.

[0013] Cooling channels can be guided from the outside of the battery cell to the inside of the battery cell, for example, through an input opening provided in the cell housing. Similarly, cooling channels can spatially pass through the interior of the cell and then be guided outwards from the inside of the battery cell, for example, through an output opening provided in the cell housing. Here, in particular, not only a single cooling channel can be guided through the cell housing, but, for example, multiple cooling channels can be guided through the cell housing. Thus, in this case, multiple input and output openings can be provided for each corresponding cooling channel, all arranged in the cell housing. In principle, it is also conceivable that the input and output connectors for the cooling channels are guided through the same opening in the cell housing. However, it is preferable that the input and output connectors for the respective cooling channels each have their own input and output openings in the cell housing, as this simplifies the sealing of the relevant openings, which will be explained in detail later.

[0014] In a particularly advantageous embodiment of the invention, the cooling system includes a control device designed to control the flow of cooling medium through at least one cooling channel, particularly adjusting the cooling medium flow and / or pressure to a predetermined maximum value upon detection of an impending collision or other detected hazardous situation. This advantageously improves collision safety significantly in the event of an accident, as reinforcement of the individual battery cells and the entire cell assembly can be achieved by purposefully increasing the cooling medium flow or pressure upon detection of an impending collision, as explained above. This is particularly advantageous when at least one area of ​​the channel wall is formed by a portion of the cell housing or pressed against a portion of the cell housing due to the cooling medium pressure. This allows for purposeful external reinforcement of the cell housing. For example, the control device for the cooling system can be in communicative connection with another system in the vehicle designed for detecting impending collisions (e.g., a collision warning system or a collision avoidance system). If an imminent collision with another object is detected, the control device can control the cooling medium flow such that the cooling medium pressure within the cell housing is increased to a predetermined maximum value. This maximizes the rigidity of the battery cells.

[0015] Alternatively or additionally, the control device may be designed to control the flow of cooling medium through at least one cooling channel based on the currently required cooling power and / or battery power and / or battery current and / or battery temperature. Generally, the control device may also be designed to control the flow of cooling medium based on situation parameters. These situation parameters may be related to the currently required cooling power and to the detection of impending hazardous situations, especially collisions.

[0016] In another advantageous embodiment of the invention, the battery cell has at least one cell electrode terminal disposed on a first side of the cell housing, and a cell component disposed within the cell housing has at least one current collector electrically connected to at least one cell electrode terminal. A cooling channel is arranged such that at least one flexible region of the channel wall is pressed against the current collector due to the pressure of the cooling medium. This provides particularly effective cooling because the strongest heat generation of the battery cell typically occurs in the region of the current collector. Here, it is the current collector connected to the positive electrode that typically constitutes a temperature hotspot in the cell. This temperature hotspot can be purposefully cooled by the advantageous embodiment of the invention. Cooling efficiency is thus maximized. Furthermore, it is particularly advantageous that not only one current collector is cooled, but both current collectors disposed within the cell housing are cooled. For example, the cooling channel can be designed to be guided not only through the first current collector but also through the second current collector, so that when the cooling medium flows through the channel, the cooling channel is pressed against not only the first current collector but also the second current collector. For example, the first current collector may be assigned to the positive electrode terminal of the battery cell, and the second current collector may be assigned to the negative electrode terminal of the battery cell. However, it is also conceivable to integrate two separate cooling channels into a single battery cell, that is, within its casing, with one cooling channel allocated to the first current collector and the other to the second current collector. Therefore, when the cooling medium flows through the first cooling channel, it presses against the first current collector, and the second cooling channel correspondingly presses against the second current collector using its channel walls. This allows for targeted cooling of both current collectors, thereby further improving cooling efficiency.

[0017] Furthermore, it is preferable that at least the flexible area of ​​the channel wall is made of an electrically insulating material. This ensures that voltage breakdown or short circuits will not occur. However, it is also conceivable that at least one cooling channel is constructed in the form of an aluminum flexible tube with a thin aluminum wall. Sufficient flexibility to achieve the desired tight fit can also be provided by constructing a very thin metal wall. For example, a cooling channel with a metal wall may also have a corresponding insulating layer on the outside. However, it is preferable that the channel wall is made of an electrically insulating material, especially plastic. This additionally allows the channel wall to be designed at least partially to be elastic, at least in a simplified manner. This partial elasticity of the channel wall allows it to expand or contract, for example, according to the pressure of the cooling medium flowing through the cooling channel, thereby also providing other possibilities for matching the geometry of the component to be cooled (in this case, the individual component, especially the current collector).

[0018] In another advantageous embodiment of the invention, a portion of the channel wall may be provided by the monolithic housing itself. For example, the channel may be defined by a channel wall partially formed from a portion of the monolithic housing wall and partially formed by a flexible, particularly elastic, diaphragm disposed internally at the monolithic housing. This variation is particularly advantageous when, for example, the monolithic housing itself is also made of plastic. In this case, the diaphragm, preferably also made of plastic, can be connected to the monolithic housing, for example, by welding, with particular ease. Thus, a flexibly sized cooling cavity through which the cooling medium can flow is provided by the monolithic housing wall and the diaphragm tensioned between the areas of the monolithic housing wall.

[0019] In a preferred embodiment of the invention, the channel wall is provided by a flexible hose guided through the cell housing. This significantly simplifies the integration of the cooling channel into the cell housing and provides great flexibility in the arrangement of the guided channel. In principle, this hose can be made of metal, but is preferably made of plastic, especially a flexible and preferably equally elastic plastic. This hose can, for example, be guided through the cell housing in a U-shape, and thus guided around the current collector in a particularly simple manner for particularly efficient cooling of the current collector. One half of this hose located in the cell housing can be correspondingly located between the current collector and a first sidewall of the cell housing, and the second half of the hose can be located between the current collector and a second sidewall of the cell housing opposite the first sidewall. Preferably, the sidewall is the sidewall with the largest area of ​​the battery cell, specifically its cell housing. Correspondingly, a second hose providing a second cooling channel can also be arranged in the cell housing, the second hose also arranged in a U-shape around the second current collector. Thus, the first half of the second hose is located between the second current collector and the first sidewall, and the second half of the second hose is arranged between the second current collector and the second sidewall of the cell housing. However, it is also possible to use only a single flexible hose, which is U-shaped and wound around the first current collector, passing through the interior of the battery cell at a horizontal line relative to the determined installation position of the battery cell in the vehicle, and guided to the second current collector, which is also U-shaped. Thus, cooling of both current collectors can be provided through a single hose. Furthermore, it is particularly advantageous that the inlet and outlet openings of this hose are arranged in the upper side of the battery cell, specifically in its cell housing, that is, at the location where the cell terminal connectors are also located. By providing the inlet and outlet openings in this area, it is possible to simply surround the corresponding cell current collectors inside the battery cell with the U-shaped extending hose. At the same time, the upper side of the battery cell provides significantly greater stability due to the significantly thicker cell housing construction there, allowing for the provision of one or more openings on one hand, and on the other hand, for example, connectors and sealing schemes in the opening area. Nevertheless, it is also conceivable to provide the inlet and outlet openings on either side of the battery cell housing.

[0020] Furthermore, it is advantageous that the ends of the hose are arranged sealingly at the openings in the areas of the inlet and outlet openings, and, for example, a connection area is provided for connecting further extending hoses or conduits (e.g., extending to a coolant reservoir). For example, if both the housing and the hose are made of plastic, this sealing connection, particularly preventing coolant from seeping into the interior of the housing, can be simply provided by, for example, by having the edges of the corresponding hose ends welded around or otherwise sealingly connected at the inlet or outlet openings. This also applies, for example, when both the housing and the hose are made of metal. Conversely, if, for example, the hose is made of plastic and the housing is made of metal, other sealing methods, which will be explained in detail below, are preferred.

[0021] In these embodiments, at least one input opening is arranged in the monolithic housing, and the hose has a first end that extends from the monolithic housing through the input opening. In a first embodiment of the invention, the monolithic housing has a fixed region surrounding the input opening, and the cooling system has a fixing element, wherein the first end of the hose has an inner side and an outer side opposite to the inner side, and wherein the end of the hose is fixed between the fixed region and the fixing element such that the outer side abuts against the fixed region and the inner side abuts against the fixing element. In the simplest case, the fixed region provided by the monolithic housing and surrounding the input opening can constitute a region of the monolithic housing in which the input opening is provided, for example, in the form of a hole or aperture guiding from the outside to the inside of the monolithic housing. In other words, in this case, the fixed region simply constitutes a housing region directly connected to the aperture, for example, an annular housing region surrounding the aperture. Here, the fixed region extends substantially perpendicular to the extending direction of the input opening from the outside to the inside. Therefore, the hose, for example, can be guided outward through the input opening using one end, folded outward to a certain right angle onto the fixed region, and fixed by the fixing element. For example, the retaining element can be pressed annularly onto the folded edge of the hose, similar to a gasket. The retaining element can also simultaneously provide a fitting for the conduit. For example, the retaining element can be configured as a sleeve with a flange facing the monocoque housing, in this example, the flange extending substantially perpendicular to the extension direction of the sleeve or connecting pipe. Thus, according to the example, the hose end is advantageously pressed between the retaining element and the retaining area, thereby achieving a seal. Additionally, it can be specified that an O-ring is used to improve the seal, for example, arranged between the retaining area and the outer side of the hose end, or between the inner side of the hose end and the retaining element. With such an O-ring, a higher local pressure can be provided, thereby improving the seal.

[0022] In another preferred sealing variant according to another embodiment of the invention, the cooling system has a fixing element and a flange arranged on the edge region of the inlet opening, surrounding the inlet opening and extending from the monolithic housing at a non-zero angle. This flange has a side facing the inlet opening, providing a fixing region, wherein the end of the hose has an inner side and an outer side opposite to the inner side, wherein the end of the hose is fixed between the fixing region and the fixing element such that the outer side abuts against the fixing region and the inner side abuts against the fixing element. For example, this flange may have a funnel-shaped geometry that narrows towards the inlet opening. The hose can extend from the inlet opening using its end and is placed on the inner side of the funnel using its outer side and pressed against the funnel by the fixing element, which may also be funnel-shaped and abut against the inner side of the hose. A connecting element can also be provided simultaneously, for example, by connecting a tubular region, for example, a connecting sleeve, to the funnel-shaped region of the fixing element, for example. In other words, the fixing element can be constructed as described previously, that is, annularly having a flange connected to the end of the pipe, except that in this case, the flange does not extend vertically from the pipe, but is angled relative to the pipe. The advantage of this implementation variation is that the hose does not need to be folded vertically at its end extending from the inlet, but only at an angle of less than 90 degrees, which is gentler on the hose and improves its service life.

[0023] To further improve sealing, the flange may be specified to have a free edge not arranged on the monocoque housing, wherein the end of the hose is folded over the edge of the flange. This folding enclosure further makes it more difficult for the cooling medium to leak from the hose in the connection area. Multiple folds at the hose end are also conceivable for further improving sealing.

[0024] The described scheme can be implemented not only in terms of the input opening, but also in a completely similar manner in the second hose end, which extends from the output opening in the monolithic housing.

[0025] In another advantageous embodiment of the invention, at least one input opening is provided in a portion of the cell housing for conveying cooling medium to a cooling medium channel, wherein the battery cell has two cell electrode terminals on the outer side of one side of the cell housing, and wherein at least one input opening is arranged in a first side of the cell housing. As described, it is particularly advantageous that the input opening, and especially the output opening, is similarly arranged in the upper side of the corresponding cell housing, where the cell electrode terminals are also located, because in this region the cell housing wall is significantly thicker than in other regions of the cell housing. Thus, when one of the above-described sealing methods is implemented in the regions of the input and output openings, this ensures significantly higher stability. A single battery cell may, for example, have an upper side (on which two cell terminals are also provided), a lower side opposite to the upper side, a front side, a rear side, and a fifth and a sixth side. The front and rear sides provide the aforementioned first and second sidewalls and are also arranged opposite each other, providing the side with the largest area of ​​the battery cell. The fifth and sixth sides are also arranged opposite each other and are different from the upper, lower, front, and rear sides. The cell housing may have a wall thickness of, for example, 1.2 mm to 1.5 mm on the upper side, while the wall thickness of the cell housing on all the remaining sides is less than 1 mm, for example, 0.8 mm.

[0026] Nevertheless, the input and output openings of the battery cell can also be arranged on any other side of the cell housing, such as the front and rear sides of the cell housing and / or a narrow side different from the upper, lower, front, and rear sides. In this case, it is advantageous to arrange the input and output openings on opposite sides of the cell housing to simplify the guidance of cooling channels through the cell housing, but this is not always necessary.

[0027] Alternatively, a battery bank may be provided, comprising multiple battery cells constructed in the same manner, each having a flow-through cooling channel integrated into its respective cell housing. These cooling channels can be provided via respective flexible hoses. For example, the hoses of multiple battery cells may converge on a common collection line located outside the cell housing. For each battery cell, this means, for example, that the cooling channel extends from the collection line into the cell housing, extends partially within the cell housing, extends from the cell housing, and extends back into the collection line. Here, the channel need not be constructed as a single piece, but may, for example, have a conduit from the collection line to the cell housing, and thus, for example, connect to a hose described in the cell housing, the hose being reconnected via another end to the conduit returning to the collection line. However, in another variation, it may be specified that the cooling channel is simultaneously guided through multiple battery cells. For example, the hose may be guided through one battery cell, extending from its cell housing, and directly into the next cell housing, being guided through that next cell housing, extending from that next cell housing, and into another cell housing, and so on. The hoses or cooling channels guided through multiple individual housings can be constructed as a single piece, meaning they are not individual hose components inserted together. Alternatively, for example, each housing can be assigned its own independent cooling channel, and the respective cooling channels, such as the respective hoses, extend on the front and rear sides and are inserted together or otherwise connected during housing assembly. In both cases, it is advantageous and preferred to provide a seal, such as one of the sealing schemes described above, in the area of ​​the opening in the housing.

[0028] This achieves a particularly effective implementation scheme. Conversely, the advantage of a variant scheme with unit-specific cooling channels, i.e., not guided from unit to unit, is that it enables a particularly modular structure that is simple in terms of assembly technology.

[0029] Furthermore, the present invention also relates to a battery, particularly a high-voltage battery, having a cooling system or design according to the invention. For example, such a high-voltage battery may have multiple battery modules, each of which has multiple battery cells, such as those described in conjunction with the cooling system or embodiments thereof. A central control device may be provided to control the flow of the cooling medium. Here, the flow of the cooling medium can be controlled individually for each cell or uniformly for all battery cells. The uniform control for all cells is particularly advantageous because each individual battery cell is typically subjected to the same load during vehicle operation, thereby significantly simplifying control complexity.

[0030] In addition to maneuvering based on the detected impending collision, the control unit is also designed to control the flow of cooling medium according to current cooling requirements. Here, the control unit can be configured as a closed-loop control system, meaning that the flow of cooling medium can be controlled or adjusted, for example, based on the acquired current individual cell temperature, module temperature, or battery temperature. If the individual cell temperature rises, the cooling power can be increased by increasing the flow of cooling medium. In this way, high cooling power can also be temporarily provided when, for example, a charging current greater than 100 kW is reached. This accelerates the charging process and also increases the maximum output power of the battery.

[0031] Furthermore, the present invention also relates to a motor vehicle having a cooling system according to the invention or one of its design embodiments. Thus, the advantages described for the cooling system and its design embodiments according to the invention are applied in the same manner to the battery according to the invention and the motor vehicle according to the invention.

[0032] The motor vehicle according to the invention is preferably configured as an automobile, especially a passenger car or a truck, or a bus or a motorcycle.

[0033] Furthermore, the present invention also relates to a method for cooling battery cells for use in motor vehicles, wherein the battery cell includes a cell housing and cell components disposed within the cell housing, and wherein at least one cooling channel for cooling the battery cell is traversed by a cooling medium, wherein the cooling channel is designed to have channel walls that are at least partially configured to be flexible. Here, at least one cooling channel is at least partially disposed within the cell housing, wherein when the cooling channel is traversed by a cooling medium having a specific cooling medium pressure, at least one flexible region of the channel wall presses against at least a portion of the cell component due to the cooling medium pressure.

[0034] Hereinafter, the advantages described in the cooling system and its embodiments according to the invention are applied in the same manner to the method according to the invention.

[0035] This invention also includes improvements to the method according to the invention, which have features already described in conjunction with improvements to the cooling system according to the invention. For this reason, corresponding improvements to the method according to the invention will not be described again here. Attached Figure Description

[0036] Figure 1 A schematic perspective view of a cooling system having a battery cell according to a first embodiment of the present invention is shown;

[0037] Figure 2 Shown without components under the monocoque housing Figure 1 A schematic 3D view of the cooling system in the image;

[0038] Figure 3 The front view shows Figure 1 A schematic diagram of the cooling system in the middle;

[0039] Figure 4 A front view is shown without the sub-shell components. Figure 1 A schematic diagram of the cooling system in the middle;

[0040] Figure 5 A schematic perspective view of a cooling system according to a second embodiment of the present invention is shown;

[0041] Figure 6 A schematic diagram of a cooling system according to a third embodiment of the present invention is shown;

[0042] Figure 7 A schematic perspective view of a cooling system according to a fourth embodiment of the present invention is shown without any components under the single-unit housing.

[0043] Figure 8 Shown in front view Figure 7 A schematic diagram of the cooling system in the middle;

[0044] Figure 9 A schematic cross-section of the cooling system under low cooling medium pressure is shown in top view.

[0045] Figure 10 This demonstrates the condition with higher cooling medium pressure. Figure 9 A schematic cross-sectional view of the cooling system;

[0046] Figure 11 A schematic cross-sectional view of a cooling system according to another embodiment of the present invention is shown in top view. The cooling system has cooling channels whose channel walls are partially provided by a single housing.

[0047] Figure 12 A top view is shown to illustrate the different locations of the input and output connectors;

[0048] Figure 13 A schematic cross-sectional view of a portion of the cooling system is shown in a side view to illustrate a first sealing scheme according to an embodiment of the invention;

[0049] Figure 14 A schematic cross-sectional view of a portion of the cooling system is shown in the side view to illustrate a second sealing scheme according to an embodiment of the invention; and

[0050] Figure 15A schematic cross-sectional view of a portion of the cooling system is shown in a side view to illustrate a third sealing scheme according to an embodiment of the invention. Detailed Implementation

[0051] The embodiments described below are preferred embodiments of the present invention. The components of the embodiments described in the embodiments represent individual features of the invention that are considered independent of each other, and these features also independently improve the invention. Therefore, the disclosure should also include combinations of features different from those of the illustrated embodiments. Furthermore, the described embodiments may be supplemented by other features of the invention already described.

[0052] In the figure, the same reference numerals represent elements with the same function.

[0053] Figure 1 A schematic perspective view of a cooling system 10 having a battery cell 12 according to an embodiment of the present invention is shown. Here, the battery cell 12 has a cell housing 14, which includes an upper cell housing component 16 and a lower cell housing component 18. Here, the upper cell housing component 16 provides one side of the battery cell 12 on which the cell terminal 20 of the battery cell 12 is also arranged. The remaining portion of the cell housing 14 is indicated by 18. Figure 2A schematic diagram of the cooling system 10 is shown again without the lower component 18 of the cell housing to illustrate the internal structure of the battery cell 12. Here, the battery cell 12 has a cell component 22 arranged in the cell housing 14. In this example, the cell component includes a cell core 24 and two current collectors 26. Here, the current collectors 26 are electrically connected to the corresponding cell terminal 20 of the battery cell 12. To cool the battery cell 12, the cooling system 10 now advantageously has cooling channels through which a cooling medium can flow, the cooling channels being integrated into the cell housing 14. In this example, the cooling channel 28 is constructed as a flexible, and in particular, elastic, hose 30. In particular, in this example, the cooling system 10 has two such cooling channels 28, which are spatially separated from each other. For each corresponding cooling channel 28, in this example, an inlet opening and an outlet opening 34 in the form of a hole or aperture are provided in the cell housing 14. Furthermore, in this example, an inlet connector 36 and an outlet connector 38 are arranged around the corresponding inlet opening 32 and outlet opening 34. Therefore, an inflow section for the cooling medium is provided through the input connector 36 and the corresponding input opening 32, and a corresponding outflow section for the cooling medium is provided through the associated output connector 38 and the corresponding output opening 34. Furthermore, the corresponding hose 30 is U-shaped and wound around the corresponding current collector 26. Moreover, the hose 30 is configured such that when a cooling medium with a specific cooling medium pressure flows through the hose, the hose presses against at least a portion of the unit component 22 due to the cooling medium pressure, in this example, against the current collector 26. This advantageously provides a dynamically deformable unit core current collector cooling section that actively (i.e., depending on the situation) adheres to the unit core current collector 26 under fluid pressure, that is, under the pressure of the cooling medium. Here, the cooling medium pressure can be controlled as needed. For this purpose, a corresponding control device, not explicitly shown here, can be provided. Here, control can be performed based on cooling power requirements, for example, based on the current operating status of the battery containing the battery cell 12, or based on the current temperature of the battery or battery cell 12.

[0054] However, in a particularly advantageous manner, the cooling system 10 can also be used to significantly improve the collision safety of batteries having such a cooling system 10. This is based on the fact that by actively expanding the cooling hose 30 during or immediately after a collision, for example by increasing the corresponding cooling medium pressure, support can be provided relative to the cell housing wall 18. This, in turn, increases the overall rigidity of the cell 12, thereby protecting the cell 12 itself from foreign object intrusion. For this purpose, when a hazardous situation is detected, such as by vehicle sensors, prior notification can be given. Based on the detection of this hazardous situation, the cooling hose 30 can be further expanded, that is, the cooling medium pressure can be increased accordingly.

[0055] Figure 3 and Figure 4 They were shown again as in Figure 1 and Figure 2 The same cooling system 10 shown in the figure has and does not have a single-unit housing lower component 18, wherein, Figure 3 and Figure 4 The cooling system 10 is shown in a front view of the front side 40 of the battery cell 12. At this time, the front side 40 is in particular the side with the largest area representing the battery cell 12.

[0056] This allows for the provision of a cooling section integrated into the battery cell 12, particularly a direct cooling section for the cell core 24 or current collector 26, making cooling especially effective as it provides cooling at the points where heat is generated. Furthermore, this results in significant packaging improvements, as a cooling section below the battery cell 12 is no longer necessary. Correspondingly, gap filler can also be eliminated, leading to cost improvements. Moreover, this type of cooling section allows for charging power exceeding 300 kW without any issues.

[0057] Here, the number and location of the inflow and outflow portions for the cooling medium provided by the corresponding input connectors 36 and output connectors 38, and the corresponding input and output openings 32, 34 in the single housing 14, can be varied according to the embodiment. Here, at least one opening 32, 34 exists in the single housing 14. This single opening can simultaneously provide both the inflow and outflow portions. In other words, a common opening for providing both the inflow and outflow portions is theoretically conceivable. However, preferably, at least one input opening 32 and one output opening 34 are provided in the single housing 14. Here, each current collector 26 can have its own inflow and outflow portion. Alternatively, one inflow and one outflow portion can correspond to multiple current collectors 26. In principle, the positions of the input and output openings 32, 34 and the corresponding connectors 36, 38 can also be provided at any location on the single housing 14.

[0058] Here, Figure 5 An example of a cooling system 10 is shown, which is constructed as described above, except that the input and output openings 32, 34 are not arranged in the upper side 16 of the monocoque housing 14, but rather on opposite sides 42, 44. These sides are different not only from the upper side 16, but also from the lower side 46 opposite to the upper side 16, and from the front and rear sides 40, 48. Therefore, the connectors 36, 38 are laterally located on the narrow side of the monocoque housing 14.

[0059] Figure 6 Another variation of the cooling system 10 is shown, in which the cooling system can also be as described above. Figures 1 to 4The configuration is as described, except that the input and output connectors 36 and 38 are now arranged on the front 40 and rear 48 of the cell housing 14, that is, on the side with the largest area of ​​the battery cell 12. Therefore, the connectors 36 and 38 are located on the large surfaces of the cells 12 that are in contact with each other. In other words, in a battery module, multiple such battery cells 12 are typically arranged side-by-side, with their sides 40 and 48 facing each other. Typically, there are also separating elements between the cells to electrically insulate them from each other. In this variant, for example, each cell 12 can be plugged into other cells, that is, the corresponding connectors 36 and 38 are interconnected, and thus the cooling channels 28 of the multiple cells 12 are also interconnected.

[0060] Figure 7 and Figure 8 respectively Figure 7 3D diagrams and Figure 8 The front view shows yet another variation of the cooling system 10, again without showing the lower housing component 18. In this variation, the cooling system 10 has only one inlet connector 36 and only one outlet connector 38. In this example, the hose 30 providing the cooling passage 28 is guided around two current collectors 26. In other words, instead of two separate hoses 30 for the respective current collectors 26, only one hose 30 is provided, which is guided within the unit from one current collector 26 to another through a horizontal section 30a. In other words, in this example, the cooling passage 28 has a transverse passage 30a, and accordingly, the cooling system 10 also includes only one inlet on one side and one outlet on one side. In other respects, the cooling system 10 is constructed as described above for the other examples.

[0061] Figure 9 and Figure 10 Cross-sectional views of the cooling system 10 according to the example described above are shown in top view. Here, Figure 9 The cooling hose 30 is shown when it is not traversed by a cooling medium or when it is traversed by a cooling medium at low pressure. Figure 10 The diagram shows the hose 30 when it is circulated by a cooling medium with higher pressure, causing it to bulge and adhere tightly to the corresponding single-unit current collector 26. Here, the hose 30 also simultaneously supports the single-unit housing 14. This strengthens the single-unit housing 14.

[0062] Figure 11A top view shows another schematic cross-sectional view of a cooling system 10 according to another embodiment of the invention. In this example, the cooling channel 28 is not constructed as a flexible hose, but has a channel wall 50 provided in part by the monocoque housing 14 and in part by a flexible, especially elastic, diaphragm 52. When the respective cooling channel 28 is traversed by a cooling medium having a correspondingly high pressure, the diaphragm 52 is also in close contact with the monocoque housing 24, especially the current collector 26. This variation is particularly advantageous when not only the monocoque housing 14 but also the diaphragm 52 is made of plastic, because in this way the monocoque housing and the diaphragm can be connected particularly easily, for example, they can be welded to each other.

[0063] The cooling channel 28, and especially the described hose 30, can be made of virtually any material, particularly metal or plastic, and can optionally be designed as a composite structure, that is, having multiple layers in, for example, a plastic-metal-plastic layer sequence. Preferably, the cooling hose 30, or generally the cooling channel 28, is configured to be at least electrically insulated from the outside. By actively controlling the flow, the contact between the cooling hose 30, or generally the cooling channel 30 (e.g., the diaphragm 52 also shown herein), and the individual current collector 26 can be changed, thereby altering the cooling effect. This allows for adjustment of the control of the cooling power as needed.

[0064] Figure 12 Schematic diagrams of different variations 10a, 10b, and 10c of the cooling system 10 are shown, differing particularly in the positions of the inlet and outlet portions, or the inlet opening 32 and the outlet opening 34. In the first variation 10a, the inlet opening 32 is located on the rear side 48 of the single-unit housing 14, and the outlet opening is located on the front side 34, especially in relation to... Figure 6 This corresponds to the embodiment described above. In the second variant 10b, the input opening 32 and the output opening 34 are located, in particular, on the upper side 16 of the single-unit housing 14 for each current collector 26. This is especially relevant to the embodiment described above. Figures 1 to 4 The described implementation of the cooling system 10 corresponds to this. The third variant 10c shows an embodiment based on... Figure 7 and Figure 8 The example described includes the input opening 32 and the output opening 34 on the upper side 16. Here, the first variant 10a is not particularly preferred because the upper side 16 of the monolithic housing 14 is more robust than the other sides, as the upper side is typically constructed thicker. Accordingly, the joint on the upper side 16 can provide greater stability. This is particularly advantageous for the sealing scheme described below.

[0065] In particular, the sealing scheme should now be described with reference to the cooling channel 28 configured as a flexible hose 30. Here, this flexible hose 30 extends from the inlet opening and the outlet opening at its respective ends, and must be sealed at these locations so that the cooling medium cannot flow out of the hose and into the unit 12 in this connection area. This is described here with reference to the single end 30b of this flexible hose, taking the inlet opening 32 as an example, but this can also be similarly achieved at the other end of the flexible hose 30 (which similarly extends from the outlet opening 34).

[0066] Figure 13 A first example of a sealing scheme is shown. Here, a portion of the cooling system 10 is shown in cross-section through the hose 30. Here, 30b represents the hose end, and 30c represents the edge of the hose end 30b. Thus, the hose end 30b extends from the input opening 32 (which can be simply represented, for example, as a hole in the housing 14) and bends at a right angle in this example. The area of ​​the housing 14 surrounding the opening 32 is referred to as the fixing region 14a. This region can, for example, be annular around the opening 32. Furthermore, in this example, the cooling system 10 also includes a fixing element 54. The fixing element can also be configured annularly and arranged to surround the opening 32. Now, the hose end 30b is clamped or pressed between the fixing region 14a and the fixing element 54. For example, an input connector 36 can also be connected to the fixing element 54, and the input connector can be configured, for example, as a sleeve. In other words, the fixing element 54 can be represented as a flange on the underside of the sleeve 36.

[0067] To further improve the sealing performance, an O-ring 56, i.e., an annular sealing element, can also be provided. The O-ring can also be arranged between the fixing region 14a and the fixing element 54. This O-ring 56 locally increases the pressure acting on the hose end 30b, thus improving the sealing performance. Therefore, in this example, the hose end 30b is folded or folded over the outside of the housing 14 in the fixing region 14a and secured on the upper side by the fixing element 54. The fixing element 54 can also continue to extend radially relative to the opening 32 and, for example, be connected to the housing 14 on the outside, such as by welding or pressing together, or otherwise fixed to the housing 14. In this example, the hose wall at the hose end 30b is folded at a right angle. Figure 13 In this context, the angle is always represented by β. Figure 14 The diagram shows a slightly simpler variation of hose 30.

[0068] Here, Figure 14Also shown is a schematic cross-sectional view of a portion of the cooling system 10 in the area of ​​the inlet opening 32 in the housing 14, with the hose end 30b again guided through the inlet opening and sealed according to the second sealing scheme. In this example, at the inlet opening 32 in the monolithic housing 14, particularly at the edge of the limiting inlet opening 32 of the monolithic housing 14, a funnel-shaped surrounding flange 14b is arranged. That is, the flange 14b tapers towards the opening 32. Furthermore, a retaining element 54 is also provided here again; now, the retaining element is not like... Figure 13 Instead of being constructed in a disc shape, it is also funnel-shaped. The hose end 30b is again clamped between the fixing element 54 and the flange 14b. The edge 30c of the hose end 30b can extend completely from the intermediate region between the fixing element 54 and the flange 14b. In this case, two sealing regions are obtained. One is created by applying a force perpendicularly downward from the funnel-shaped edge outside the fixing element 54 toward the monocoque housing 14 to the hose end 30b in the region of the flange edge. The other sealing region is provided by applying a force perpendicular to the contact surface to the hose end 30b in the intermediate region of the surface shape between the fixing element 54 and the flange 14b.

[0069] In this example, flange 14b is inclined at an angle α relative to the monocoque housing 14. Thus, the inclination angle β of the hose wall is obtained in the region of hose end 30b compared to the hose wall within opening 32. Here, this angle β is greater than 90 degrees, which is more gradual for the hose end.

[0070] Generally, this angle β can have virtually any value, for example, between 0 degrees and 355 degrees. This can be achieved by constructing the edge region of the monolithic housing 14 with a corresponding geometry around the opening 32. Thus, the hose end 30b can be folded outwards at any angle until, for example, the outer sides of the hose end 30b are again parallel and aligned with each other. The hose end 30b can also be folded inwards so that the corresponding inner surfaces of the hose end 30b are oriented towards each other and substantially parallel to each other.

[0071] Generally, the inner side or hose wall of hose 30 is defined as the side of hose 30 that comes into contact with the cooling medium during operation. Correspondingly, the outer side is the side of hose wall of hose 30 opposite to the inner side.

[0072] To further improve the sealing performance, the hose end 30b, especially the hose edge 30c, is... Figure 14 The end of the hose 30b can be folded again around the flange 14b, for example, around its outer edge. This repeated folding at the hose end further improves the seal. Figure 15Another variation of this multiple-folding scheme is shown in the figure. Figure 15 A schematic cross-sectional view of a portion of the cooling system 10 with a third sealing scheme is also shown again. (Compared to...) Figure 14 Similarly, this cooling system 10 also again has a funnel-shaped flange 14b, which is arranged in the edge region surrounding the opening 32 at the monolithic housing 14, and has a corresponding funnel-shaped fixing element 54. However, now the hose end 30b does not extend outward from the opening 32 between the fixing element 54 and the flange 14b, but is completely within the fixing element 54 and then folded around the outer edge of the fixing element 54 by its edge 30c, and then spatially fixed between the fixing element 54 and the flange 14b or clamped between the two elements by the edge 30c. In order to further improve the sealing of this arrangement, another second fixing element 58, such as a re-annular fixing element 58, may optionally be used. Figure 13 The fixing element 54 is similarly fitted or pressed onto the arrangement structure from above. Subsequently, the sleeve 36 for providing the input connector 36 is again connected to the second fixing element 58.

[0073] Many other sealing schemes are also conceivable. Here, this is merely one option used to illustrate the basic sealing principle, whereby the hose end is clamped between the housing component 14a or the component 14b on the housing 14 and the individual fixing element 54. Furthermore, in Figure 14 and Figure 15 The variant shown in the diagram for improving sealing performance can also be as follows: Figure 13 An O-ring 56 is additionally used as shown. Thus, the O-ring can also be arranged between the flange 14b and the fixing element 54.

[0074] In general, the examples illustrate how the present invention provides actively controllable cell cooling, wherein, according to the invention, at least one cooling channel is integrated into the cell housing and thereby provides an actively deformable cell core current collector cooling section, which is actively, i.e., in close contact with the cell core current collector under fluid pressure, i.e., as appropriate. This allows for direct cooling of the cell core at locations where heat is also generated. Improved packaging is achieved because an additional cooling section below the cell is no longer required. Correspondingly, cost improvements are provided because thermal bonding via gap filler is also unnecessary in this case. Furthermore, significantly higher charging power for charging the battery cell, especially above 300 kW, can be advantageously provided without problems through better cooling.

Claims

1. A cooling system (10) for cooling a battery cell (12) for use in a motor vehicle, wherein, The cooling system (10) includes cooling devices (28, 30, 50) and battery cells (12). Each battery cell includes a cell housing (14) and cell components (22, 24, 26) arranged within the cell housing (14). The cooling devices (28, 30, 50) have at least one cooling channel (28) through which a cooling medium can flow. This cooling channel is constructed with channel walls (30, 50, 52, 14), which are at least partially flexible. The at least one cooling channel (28) through which the cooling medium can flow is at least partially arranged within the single housing (14) and configured such that when the cooling channel (28) is flowed by a cooling medium having a specific cooling medium pressure, at least one flexible region (30, 52) of the channel wall (30, 50, 52, 14) presses against at least a portion of the single component (22, 24, 26) due to the cooling medium pressure, wherein the cooling system (10) has a control device designed to control the flow of cooling medium through the at least one cooling channel (28) based on the detection of an impending collision, and to adjust the flow of cooling medium and / or the cooling medium pressure to a predetermined maximum value in the event of an impending collision.

2. The cooling system (10) according to claim 1, characterized in that, The battery cell (12) has at least one cell electrode connector (20) arranged on the outside of the cell housing (14) on a first side (16), and the cell components (22, 24, 26) arranged in the cell housing (14) have at least one current collector (26) electrically connected to at least one cell electrode connector (20), wherein the cooling channel (28) is arranged such that at least one flexible region (30, 52) of the channel wall (30, 50, 52, 14) presses against the current collector (26) due to the pressure of the cooling medium.

3. The cooling system (10) according to claim 1 or 2, characterized in that, At least the flexible regions (30, 52) of the channel walls (30, 50, 52, 14) are made of electrically insulating material and / or constructed to be elastic.

4. The cooling system (10) according to claim 1 or 2, characterized in that, The channel walls (30, 50, 52, 14) are provided by hoses that are guided through the monolithic housing (14).

5. The cooling system (10) according to claim 4, characterized in that, An input opening (32) is arranged in a single housing (14), wherein a hose has a first end (30b) extending from the single housing (14) through the input opening (32), wherein the cooling system (10) has a fixing element (54) and a flange (14b) arranged on the edge region of the input opening (32), surrounding the input opening (32) and extending from the single housing (14) at a non-zero angle (α), the flange having a side (16) facing the input opening (32), the side providing a fixing region, wherein the first end (30b) of the hose has an inner side and an outer side opposite to the inner side, wherein the end (30b) of the hose is fixed between the fixing region of the flange (14b) and the fixing element (54) such that the outer side abuts against the fixing region and the inner side abuts against the fixing element (54).

6. The cooling system (10) according to claim 5, characterized in that, The flange (14b) has a free edge not arranged on the monolithic housing (14), wherein the end (30b) of the hose is folded over the edge of the flange (14b).

7. The cooling system (10) according to claim 4, characterized in that, An input opening (32) is arranged in a single housing (14), wherein a hose has a first end (30b) extending from the single housing (14) through the input opening (32), wherein the single housing (14) has a fixed region (14a) surrounding the input opening (32), and the cooling system (10) has a fixing element (54), wherein the first end (30b) of the hose has an inner side and an outer side opposite to the inner side, wherein the end (30b) of the hose is fixed between the fixed region (14a) and the fixing element (54) such that the outer side abuts against the fixed region (14a) and the inner side abuts against the fixing element (54).

8. The cooling system (10) according to claim 4, characterized in that, At least one input opening (32) is arranged in a portion of the single-cell housing (14) for conveying cooling medium to a cooling medium channel (28), wherein the battery cell (12) has two cell terminal connectors (20) on the outer side of a first side (16) of the single-cell housing (14), wherein the at least one input opening (32) is arranged in the first side (16) of the single-cell housing (14), or in the front or rear side (40, 48) of the side (40, 48) that is different from the first side (16) and constitutes the single-cell housing (14) with the largest area, or in a side (42, 44) of the single-cell housing (14) that is different from the front, rear, upper and lower sides (40, 48, 16, 46).

9. A method for cooling a battery cell (12) for use in a motor vehicle, wherein, The battery cell (12) includes a cell housing (14) and cell components (22, 24, 26) arranged in the cell housing (14), wherein at least one cooling channel (28) for cooling the battery cell (12) is traversed by a cooling medium, wherein the cooling channel (28) is configured to have channel walls (30, 50, 52, 14), which are at least partially configured to be flexible, characterized in that the at least one cooling channel (28) is at least partially arranged within the cell housing (14), wherein when the cooling channel (28) is traversed by a cooling medium, When a cooling medium of a specific cooling medium pressure flows through, at least one flexible region (30, 52) of the channel wall (30, 50, 52, 14) presses against at least a portion of the individual components (22, 24, 26) due to the cooling medium pressure, wherein the cooling system (10) has a control device designed to control the flow of cooling medium through at least one cooling channel (28) based on the detection of an impending collision, and to adjust the flow of cooling medium and / or the cooling medium pressure to a predetermined maximum value in the event of an impending collision.

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