Battery cell arrangement

Abstract

The invention relates to a battery cell arrangement (1). This comprises a housing (2) which surrounds a housing interior (3) through which a temperature control fluid can flow. In the housing interior (3), several battery cells (20) are arranged such that a temperature control fluid guided through the housing interior (3) can absorb heat generated by this battery cell (20) through direct contact with at least one battery cell (20) and discharge it from the housing interior (3). The housing (2) comprises at least one housing wall (4) by means of which the housing interior (3) is fluidically separated from at least one channel (5, 6) for introducing or discharging the temperature control fluid into or from the housing interior (3). The at least one channel (5) is arranged on an outer side (10) of the housing wall (4) facing away from the housing interior.Formed in the housing wall (4) are a plurality of spaced-apart through-openings (7), by means of which the at least one channel (5, 6) and / or the channel (5, 6) communicate fluidically with the housing interior (3). Furthermore, at least one overpressure relief element (8) is provided in the housing wall (4), which opens when pressure is applied above a predetermined threshold, so that after opening, the housing interior (3) communicates fluidically with the at least one channel (5) or the channel (5, 6) via the overpressure relief element (8) - i.e., in addition to the through-openings (7).

Description

[0001] The invention relates to a battery cell arrangement.

[0002] An arrangement of multiple electric battery cells for supplying a motor vehicle, particularly an electric vehicle, with electrical energy is often cooled using so-called immersion cooling. In this process, a temperature control fluid—typically a dielectric liquid—is introduced into a fluid-tight housing in which the battery cells are arranged. Within the housing, the temperature control fluid comes into direct contact with the battery cells to be cooled. This allows the temperature control fluid to absorb the heat generated by the battery cells and, after absorbing the heat, to be discharged from the housing again.

[0003] Distributing the temperature control fluid to be introduced into the housing interior in such a way that the individual battery cells experience the most uniform cooling possible often proves problematic. Designing the housing accordingly is generally relatively complex and therefore expensive, as the housing must incorporate appropriate channel structures to direct the temperature control fluid to the individual battery cells in such a way that all battery cells are provided with the same cooling capacity—at least on average over time.

[0004] Irrespective of this, for safety reasons, a protective function against uncontrolled bursting in the event of thermal runaway (TR) must be implemented in the housing, which also complicates the development of simple technical solutions for the desired uniform distribution of the temperature control fluid.

[0005] It is therefore an object of the present invention to demonstrate new approaches in the development of the battery cell arrangement described above. In particular, a solution is to be found in which effective, yet technically comparatively simple, and thus cost-effective immersion cooling is implemented in compliance with safety requirements regarding a possible thermal runaway of one or more of the battery cells.

[0006] This object is solved by the subject matter of independent patent claim 1. Preferred embodiments are the subject matter of the dependent patent claims.

[0007] The basic idea of ​​the invention is therefore to equip a housing of a battery cell arrangement presented above for accommodating the battery cells with a housing wall in which both several openings and several overpressure relief devices are provided. A temperature control fluid – typically a dielectric liquid – for immersion cooling of the battery cells can be introduced into the housing via said openings and, after absorbing heat from the battery cells, can be discharged from the housing again. The overpressure relief devices serve to prevent excessive pressure in the housing in the event of thermal runaway of one or more battery cells.For this purpose, the overpressure relief devices are designed such that they open when pressurized beyond a predetermined pressure threshold, i.e., they transition from a closed, fluid-impermeable state to an open, fluid-permeable state, allowing the gas generated by the thermal runaway and causing said pressurization to escape from the housing in a controlled manner. Two different functions are thus implemented in said housing wall: firstly, the uniform introduction and discharge of a temperature control fluid required for improved immersion cooling, and secondly, a protective function against uncontrolled bursting in the event of thermal runaway. Both functions are implemented in a simple and therefore cost-effective manner in the battery cell arrangement proposed here.

[0008] In detail, a battery cell arrangement according to the invention comprises a housing which surrounds a housing interior through which a temperature control fluid can flow. A plurality of battery cells are arranged in the housing interior, such that a temperature control fluid guided through the housing interior can absorb waste heat generated by at least one battery cell through direct contact with this battery cell and dissipate it from the housing interior. The housing comprises at least one housing wall, by means of which the housing interior is fluidically separated from a channel for introducing the temperature control fluid into the housing interior or for discharging the temperature control fluid from the housing interior. The at least one channel is arranged in the region of an outer side of the housing wall facing away from the housing interior.Formed in the housing wall are a plurality of spaced-apart through-openings, through which the at least one channel fluidically communicates with the housing interior. Furthermore, at least one overpressure relief device is provided in the housing wall, which opens when pressure is applied above a predetermined threshold, so that after the respective overpressure relief device opens, the housing interior fluidically communicates with the at least one channel via this overpressure relief device, i.e., in addition to the through-openings.

[0009] In a preferred embodiment, at least one overpressure relief device can be a predetermined breaking point formed in the housing wall.

[0010] In order to ensure the desired uniform distribution of the temperature control fluid on the battery cells to be temperature controlled, in a preferred embodiment at least two, particularly preferably several, through openings can have different opening cross sections.

[0011] Particularly usefully, the overpressure relief device or the predetermined breaking point can be formed by a wall zone of the housing wall with a reduced wall thickness. The wall thickness of the housing wall is thus smaller in the area of ​​the overpressure relief devices or predetermined breaking points than in areas of the housing wall that complement the overpressure relief devices or predetermined breaking points. Such a technical implementation of the overpressure relief devices or predetermined breaking points is simple to manufacture and therefore extremely cost-effective.

[0012] According to an advantageous development, the supply channel and—alternatively or additionally—the discharge channel can extend along a direction of extension. In this development, at least two, preferably all, through-openings are arranged in the housing wall at a distance from one another, preferably equidistant, along the direction of extension. This measure can also support an even distribution of the temperature control fluid among the individual battery cells to be temperature-controlled.

[0013] According to a further advantageous development, an opening cross-section of at least two of the through openings can increase or decrease along the direction of extension.

[0014] According to another advantageous development, at least two overpressure relief devices are formed in the housing wall. Of these at least two overpressure relief devices, at least one fluidically connects the housing interior to a first channel when open, and at least one fluidly connects the housing interior to a second channel when open. In this way, both channels can be used to discharge the TR gas from the housing interior in the event of a thermal runaway. This greatly increases the protective effect against housing bursting.

[0015] According to an advantageous development, several overpressure relief devices are arranged along the direction of extension, preferably equidistant from one another, in the housing wall. This measure also improves the protection achieved against bursting in the event of a thermal runaway.

[0016] In a preferred embodiment, a separating element can protrude from the outside of the housing wall, fluidically separating the first channel from the second channel. This embodiment requires particularly little space for the supply and discharge of the temperature control fluid into and from the housing interior.

[0017] According to an advantageous development, the separating element can be designed as a web protruding from the housing wall. This web can preferably be formed integrally on the housing wall. This development is technically particularly simple to implement and therefore associated with cost advantages during production.

[0018] According to another advantageous development, the supply channel and the discharge channel can be delimited by the housing wall, in particular by said separating element, and by a housing cover of the housing. This development can also be implemented in a particularly simple technical manner and is therefore cost-effective.

[0019] Particularly preferably, at least one battery cell is arranged at a distance from the housing wall in the housing interior. This preferably applies to several, particularly preferably all, battery cells. This allows the temperature control fluid to flow through the resulting space between the respective battery cells, which increases the efficiency of the immersion cooling.

[0020] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

[0021] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0022] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0023] They show, schematically: Fig. 1 an example of a battery cell arrangement according to the invention in perspective view, Fig. 2 the housing of the arrangement of Fig. 1 in a detailed view and without battery cells arranged inside the housing, Fig. 3 the housing of the Fig. 2 in a sectional view, Fig. 4 the housing wall of the housing of the invention Fig. 1 and Fig. 2 in a separate perspective view.

[0024] The Fig. 1 shows a perspective view of an example of a battery cell arrangement 1 according to the invention, which will also be referred to below as "arrangement" for the sake of simplicity. The arrangement 1 comprises a housing 2, which surrounds a housing interior 3 through which a temperature control fluid (not shown) can flow. A plurality of battery cells 20 are arranged in the housing interior 3, so that a temperature control fluid guided through the housing interior 3 can absorb waste heat generated by one of the battery cells 20 through direct contact with this battery cell 20 and dissipate it from the housing interior 3. The individual battery cells 20 can be arranged side by side in the housing interior 3, as shown, and stacked on top of one another along a stacking direction SR. In the example scenario, the battery cells 20 together form a battery module 21.

[0025] The Fig. 2 is a partial view of the housing 2 of the Fig. 2 with the housing interior 3 without battery cells 20 arranged therein. The Fig. 3 shows the housing 2 of the Fig. 2 in a sectional view and with the battery module 21 arranged in the housing interior 3.

[0026] As in Fig. 3, the housing 2 comprises a housing wall 4, by means of which the housing interior 3 is formed as in Fig. 3 is fluidically separated from a supply channel, the first channel 5 for discharging the temperature control fluid from the housing interior 3, and from a second channel 6, also for discharging the temperature control fluid from the housing interior 3. The two channels 5 and 6 are arranged in the region of an outer side 10 of the housing wall 4 facing away from the housing interior 3, and are partially delimited by the housing wall 4. In the example scenario, a separating element 11 protrudes from the outer side 10 of the housing wall 4, which separates the first channel 5 fluidically from the second channel 6. The separating element 11 is preferably designed as a web 12 protruding from the housing wall 4, which web can be formed integrally on the housing wall 4. The separating element 11 or the web 12 and the housing wall 4 can therefore be formed in one piece and from the same material.

[0027] The Fig. 3 shows a cross section of the housing 2 perpendicular to the stacking direction SR of the battery cells 20, which corresponds to an extension direction ER along which the two channels 5 and 6 extend.

[0028] As the representation of the Fig. 3, the two channels 5 and 6 are delimited by the housing wall 4, by the separating element 11 in the form of the web 12 and by a housing wall 15 in the form of a housing cover 13 of the housing 2 as well as by a further housing wall 16 in the form of a housing trough 14 of the housing 2.

[0029] The Fig. The battery module 21 with the battery cells 20, which can be seen in Figure 1, can be arranged at a distance from the housing wall 4 in the housing interior 3, so that the temperature control fluid can be introduced into the housing interior 3 via a supply channel not shown in the figures and can flow into a space formed between the battery cells 20 and the housing wall 4. In this way, the battery cells 20 or the battery module 21 can come into direct contact with the temperature control fluid for immersion cooling.

[0030] The Fig. 4 shows the housing wall 4 in a separate view. Accordingly, several spaced-apart through-openings 7 are formed in the housing wall 4, through which the first and second channels 5, 6 fluidically communicate with the housing interior 3.

[0031] According to the Fig. 2 and Fig. 4, the through-openings 7 are arranged at a distance from one another—equidistantly in the example scenario—in the housing wall 4 along the extension direction ER. Individual, several, or all of the through-openings 7 can have different opening cross-sections (not shown). In particular, an opening cross-section of selected or all of the first through-openings 7 can increase or decrease along the extension direction ER. A section-by-section increase in combination with a section-by-section decrease in the opening cross-sections of individual through-openings 7 is also conceivable.

[0032] Furthermore, in the housing wall 4 there are several Fig. 2 and Fig. 4, recognizable overpressure relief devices 8 are provided, which each open when pressurized above a predetermined threshold value, so that after such an opening, the housing interior 3 communicates fluidically with the first channel 5 via the overpressure relief device 8 - i.e., in addition to the through openings 7. The overpressure relief devices 8 are each realized by a predetermined breaking point 9 formed in the housing wall 4 (cf. Fig. 4). The predetermined breaking points 9, in turn, can each be formed by a wall zone 19 of the housing wall 4 with a reduced wall thickness. In the example scenario, no overpressure relief devices 8 are provided in the second channel 6, which, in an open state, cause the housing interior 3 to communicate fluidically with the second channel 6 via the overpressure relief device 8—that is, in addition to the through-openings 7.

[0033] In variants of the example, however, it is possible to provide overpressure relief device 8 with such a function or with such a fluidic connection.

[0034] In the example scenario, both the first channel 5 and the second channel 6 can be a discharge channel for discharging the temperature control fluid from the housing interior 3. In this case, the temperature control fluid is introduced via at least one further channel, not shown in the figures, which thus serves as a supply channel for introducing the temperature control fluid into the housing interior 3. Alternatively, it is also conceivable that in a first variant of the example, the first channel 5 is a supply channel and the second channel 6 is a discharge channel. In a further, second variant of the example, the first channel 5 can be a discharge channel and the second channel 6 a supply channel.

[0035] In the example, the through openings 7 are arranged in a grid-like manner in two grid rows RZ1, RZ2 along the extension direction ER, wherein the overpressure relief elements 8 of both grid rows RZ1, RZ2 are each arranged at a distance from one another, preferably equidistantly, in the housing wall 4.

Claims

[1] Battery cell arrangement (1), - with a housing (2) which surrounds a housing interior (3) through which a temperature control fluid can flow, in which a plurality of battery cells (20) are arranged, so that temperature control fluid guided through the housing interior (3) can absorb waste heat generated by at least one battery cell (20) through direct contact with this battery cell (20) and can dissipate it from the housing interior (3), - wherein the housing (2) comprises a housing wall (4) by means of which the housing interior (3) is fluidically separated from at least one channel (5, 6) for introducing or discharging the temperature control fluid into or from the housing interior (3), - wherein the at least one channel (5, 6) is arranged on an outer side (10) of the housing wall (4) facing away from the housing interior (3), - wherein a plurality of through-openings (7) arranged at a distance from one another are formed in the housing wall (4), by means of which the at least one channel (5, 6) communicates fluidically with the housing interior (3), - wherein at least one overpressure relief element (8) is provided in the housing wall (4), which opens when pressure is applied above a predetermined threshold value and fluidically connects the housing interior (3) to at least one channel (5, 6) in addition to the through openings (7). [2] Battery cell arrangement according to claim 1, characterized by that at least one overpressure relief device (8) is a predetermined breaking point (9) formed in the housing wall (4). [3] Battery cell arrangement according to claim 1 or 2, characterized by that the overpressure relief device (8) or the predetermined breaking point is formed by a wall zone (19) of the housing wall (4) with reduced wall thickness. [4] Battery cell arrangement according to one of claims 1 to 3, characterized by , that - the at least one channel (5, 6) extends along an extension direction (ER), - at least two through openings (7) are arranged along the direction of extension (ER), preferably equidistantly, at a distance from one another, in the housing wall (4). [5] Battery cell arrangement according to one of the preceding claims, characterized by that at least two overpressure relief elements (8) are formed in the housing wall (4), of which at least one connects the housing interior (3) to the first channel (5) and at least one connects the housing interior (3) to the second channel (6). [6] Battery cell arrangement according to one of the preceding claims, characterized by that several overpressure relief devices (8) are arranged along the direction of extension (ER), preferably equidistantly, at a distance from one another, in the housing wall (4). [7] Battery cell arrangement according to one of the preceding claims, characterized by that a separating element (11) protrudes from the outer side (10) of the housing wall (4), which fluidically separates a first channel (5) from a second channel (6). [8] Battery cell arrangement according to claim 7, characterized by that the separating element (11) is designed as a web (12) projecting from the housing wall (4), which is preferably formed integrally on the housing wall (4). [9] Battery cell arrangement according to one of the preceding claims, characterized by that the first channel (5) and the second channel (6) are delimited by the housing wall (4), the separating element (11) and at least one further housing wall (14, 16) of the housing (2). [10] Battery cell arrangement according to one of the preceding claims, characterized by that the battery cells (20) are arranged at a distance from the housing wall (4) in the housing interior (3).

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