Battery module with a housing and integrated swelling compensation

Abstract

The invention relates to a battery module (10) comprising a housing (12), a first battery cell (14) arranged in the housing (12), and a second battery cell (16) arranged in the housing (12), wherein the housing (12) has a first base plate (18) and a second base plate (20) opposite the first base plate (18) in a first direction, wherein the first base plate (18) is arranged substantially parallel to the second base plate (20), wherein the housing (12) has two connecting elements (22) which are opposite one another in a second direction and each connect an edge of the first base plate (18) and an edge of the second base plate (20) to one another, wherein the first battery cell (14) contacts the first base plate (18) and the second battery cell (16) contacts the second base plate (20), wherein the first battery cell (14) contacts a first counter plate (26) arranged between the first and second battery cells (16), and the second battery cell (16) contacts a second counter plate (28) arranged between the first and second battery cells (14), wherein the first and second counter plates (26, 28) are spaced apart from one another, and wherein the first and second counter plates (26, 28) are each secured to the housing (12) in two opposing regions via a spring (30) that can be deflected in the first direction.

Description

[0001] Battery module with housing and integrated swell compensation

[0002] The invention relates to a battery module with housing and integrated swelling compensation.

[0003] Batteries, also called accumulators or secondary batteries, are subject to mechanical changes during charging and discharging cycles and throughout their lifespan. During these cycles, the battery cells change their volume, which is particularly pronounced in the stacking direction of the electrodes and is largely reversible (also called reversible "swelling" or "breathing," which depends on the state of charge, or SoC). Over the lifespan of a battery, the cells also change, with an irreversible increase in volume occurring again, particularly in the stacking direction of the electrodes, as the battery ages (irreversible "swelling").

[0004] When designing batteries, these "swelling" properties must be taken into account to prevent damage to components surrounding the battery. Furthermore, volume changes due to "swelling" or "breathing" of the electrodes can lead to mechanical stresses that affect the battery's performance and lifespan. To compensate for these effects, some batteries incorporate elements for volume or swelling compensation, which can be designed differently depending on the requirements.

[0005] Furthermore, controlling the temperature of the battery cells and, in particular, avoiding hotspots is crucial for battery performance and lifespan. Newer systems incorporate immersion cooling, in which the battery cells are surrounded by a thermally conductive fluid. The use of such systems is particularly relevant for applications with high demands on power density and temperature control, but requires a more complex technical implementation. Simultaneously addressing swelling and breathing is a particular challenge.

[0006] Sponge-shaped inserts, so-called "foam pads," can be used to compress cells and compensate for swelling. However, these are less suitable in combination with immersion temperature control, as the pores of the pads can become saturated and viscoelastic effects can occur. Furthermore, the plastic used in such "foam pads" may be incompatible with the dielectric materials in batteries.

[0007] Another challenge lies in the recycling and repair of batteries. Swelling compensation can be a hindrance in these processes. Furthermore, integrating swelling compensation into a battery can negatively impact energy density, as it often necessitates specific requirements for the battery casing.

[0008] There is a constant need to improve the swelling compensation of batteries, especially immersion-cooled batteries.

[0009] The problem is solved according to the invention by a battery module having the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims and the following description, each of which can individually or in combination represent an aspect of the invention.

[0010] The problem is therefore solved by a battery module comprising a housing, a first battery cell arranged in the housing and a second battery cell arranged in the housing,

[0011] wherein the housing comprises a first base plate and a second base plate opposite the first base plate in a first direction, wherein the first base plate is arranged substantially parallel to the second base plate, wherein the housing has two connecting elements opposite each other in a second direction, each connecting an edge of the first base plate to an edge of the second base plate, wherein the first battery cell contacts the first base plate and the second battery cell contacts the second base plate,

[0012] wherein the first battery cell contacts a first counter plate arranged between the first and second battery cells and the second battery cell contacts a second counter plate arranged between the first and second battery cells, wherein the first and second counter plates are opposed to each other, and wherein the first and second counter plates are each attached to the housing at two opposite areas by means of a spring which can be deflected in the first direction.

[0013] The battery module comprises a housing and two battery cells arranged within the housing. The housing has a first base plate and a second base plate, the first being essentially parallel to the second and opposite to the second in a first direction. Furthermore, the housing includes two connecting elements opposite each other in a second direction, each connecting an edge of the first base plate to an edge of the second base plate. The base plates are thus connected at one edge via the first connecting element and at opposite edges via the second connecting element. In other words, the housing forms a casing consisting of opposing base plates and connecting elements.

[0014] The first battery cell contacts the first base plate, and the second battery cell contacts the second base plate. The battery cells are thus positioned against the two base plates inside the housing. Between the first and second battery cells is a first counter plate, which is contacted by the first battery cell, and a second counter plate, which is contacted by the second battery cell. The first and second counter plates are spaced apart from each other. The first base plate therefore contacts the first battery cell, which in turn contacts the first counter plate. At a distance from the first counter plate is the second counter plate, which in turn contacts the second battery cell, which in turn contacts the second base plate. Both counter plates are attached to the housing at two opposite points by a spring that can deflect in the first direction.Thus, during "swelling", the battery cells can push the respective counter plates away from the respective base plate along the first direction, reducing the distance between the counter plates and deflecting the springs accordingly.

[0015] The battery module according to the invention enables the internal compensation of volume increases or swelling of the battery cells, thereby improving their lifespan. In particular, this internal compensation allows for a significantly thinner housing material, as only minimal external forces act upon the swelling of the battery cells. This results in weight savings and / or increased energy density. Simultaneously, the internal compensation ensures that the external dimensions remain constant during swelling, thus facilitating module replacement. Furthermore, the battery module according to the invention exhibits improved compatibility with immersion cooling, as it eliminates the need for absorbent materials that could react with the cooling medium.Furthermore, the housing does not need to be completely fluid-tight, which allows for further material savings without compromising the structural integrity or thermal performance of the module.

[0016] For the purposes of the present invention, a battery cell can be understood as a unit for electrochemical energy storage comprising a stacked arrangement of electrodes (anode / cathode) and separator(s), as well as an electrolyte, a casing and electrical connection contacts.

[0017] Preferably, the battery cells comprise electrodes that are stacked substantially in the direction of the first direction. This allows the battery cells to swell substantially in the first direction, and the resulting swelling can be particularly well compensated by the battery module without generating additional mechanical stresses in other directions. It is further preferably possible for the battery cells to have electrical connection contacts that protrude from the housing substantially perpendicular to the first and second directions. This allows for particularly simple and space-saving contacting of the battery cells, simplifying the electrical connection, reducing assembly effort, and enabling a compact design of the battery module.Preferably, the battery cells have a substantially prismatic shape, wherein the length of the battery cells perpendicular to the first and second directions is preferably greater than the length of the battery cells in the first and / or second direction. It is also preferably possible for the length of the battery cells perpendicular to the first and second directions to be greater than the length of the battery cells in the first and second directions. It is also preferably possible for the length of the battery cells in the second direction to be greater than or equal to the length of the battery cell in the first direction, particularly wherein the length of the battery cells in the second direction is greater than or equal to the length of the battery cell in the first direction.It is particularly advantageous to provide that the length of the battery cells perpendicular to the first and second directions is greater than the length of the battery cells in the first and second directions, and that the length of the battery cells in the second direction is greater than or equal to the length of the battery cell in the first direction. These dimensions make it possible, in particular, to limit the swelling of the battery cells in the first direction and to compensate for it particularly efficiently by the counter plates and springs, while simultaneously enabling improved heat dissipation via the sides of the battery cells opposite the second direction.

[0018] Preferably, the battery cells are selected from prismatic cells and pouch cells, with pouch cells being particularly preferred. This allows the battery module to have a high energy density while maintaining a low weight. Pouch cells are particularly advantageous because they allow for greater swelling, which increases the cell lifetime and enables more effective swelling compensation within the housing. The battery modules according to the invention can therefore be particularly efficient with pouch cells.

[0019] Preferably, the first and / or second battery cell each consists of several battery cells, in particular several battery cells stacked on top of each other in the first direction. It is especially preferred that the first and / or second battery cell each consists of several pouch cells, which are stacked on top of each other, particularly in the first direction. It is understood that if the first and / or second battery cell each consists of several battery cells stacked on top of each other in the first direction, one of the battery cells contacts the base plate and another of the battery cells contacts the counter plate. By using several battery cells, the dimensions of the first and second battery cells can be adjusted to the desired dimensions particularly easily.

[0020] Preferably, the first and second base plates have essentially the same shape, with the shape being particularly preferably essentially rectangular. This results in a housing with a symmetrical and stable structure, which simplifies manufacturing, increases mechanical strength, and enables efficient use of space within the battery module.

[0021] Preferably, the first and second base plates each have fastening elements on edges opposite them, perpendicular to the first and second directions, designed to positively engage a housing cover. For example, the first and second base plates each have one or more hooks or one or more eyelets for positively engaging a housing cover. This allows the housing cover to be securely and stably attached without the need for additional fasteners, simplifying assembly, increasing structural integrity, and enabling easy disassembly for maintenance, repair, or recycling.

[0022] Preferably, the first and second base plates are made of a single sheet of metal. This allows the base plates to have high mechanical stability while maintaining a low material thickness, thus reducing the weight of the battery module. Furthermore, this improves heat dissipation and enables cost-effective manufacturing.

[0023] Preferably, the opposing connecting elements have essentially the same shape, with the shape being particularly preferably essentially rectangular. It is also preferred that the opposing connecting elements consist of a metal sheet. This also results in a housing with a symmetrical and stable structure, increases its mechanical strength, and enables simple and cost-effective manufacturing without compromising structural integrity.

[0024] Preferably, at least one of the opposing connecting elements may be integrally formed with at least one of the base plates.

[0025] This ensures a particularly stable connection between the base plate and the connecting element. Furthermore, it simplifies the manufacturing of the housing. Preferably, the first and second base plates are integrally formed with the two opposing connecting elements.

[0026] Preferably, the counter plates have essentially the same shape, with the shape being particularly preferably essentially rectangular. Preferably, the counter plates are made of a metal sheet. This ensures that the counter plates provide a uniform force distribution on the battery cells, enabling efficient swelling compensation, while the use of metal sheets offers high mechanical stability with low material thickness and simplifies manufacturing.

[0027] Preferably, the first and second counter plates are attached to the housing at opposite points in the second direction by means of a spring that can deflect in the first direction, particularly at the opposing connecting elements. This allows the counter plates to react flexibly to the swelling of the battery cells, thereby reducing mechanical stresses, extending the service life of the cells, and enabling uniform compensation, while simultaneously fixing the spring within the housing.

[0028] Preferably, the opposing areas where the first and second counter plates are attached to the housing via the spring that can be deflected in the first direction are opposite edges of the first and second counter plates. It is also preferably possible for the spring to extend substantially along the entire edge of the first and second counter plates, respectively.

[0029] Preferably, the spring is a metal sheet extending along an edge of the first and / or second counter plate and aligned parallel to the opposing connecting elements. It is also preferred that the metal sheet of the spring has several recesses designed to allow it to deflect along the first direction. In particular, the metal sheet of the spring may have several elongated recesses, each extending obliquely in its longitudinal direction relative to the first direction. This allows the spring to be integrated into the housing in a space-saving manner. Furthermore, this configuration enables the spring to have a uniform and defined spring constant along the entire edge of the counter plates, while the recesses allow for precise adjustment of the spring constant.Furthermore, this makes it possible to produce springs that are particularly easy to manufacture and save material.

[0030] Preferably, the springs are integrally designed with the first and / or second counter plate. This reduces the number of components, simplifying manufacturing, decreasing assembly effort and weight, and ensuring a particularly stable and durable connection between the counter plates and the springs.

[0031] Preferably, the springs are bonded to the housing by a material connection, for example, via a weld. This allows for a particularly strong and durable fixation. Alternatively, and preferably, the springs are bonded to the housing by a positive-locking connection in the first direction. This allows the springs and counter plates to be reused, and the battery module is particularly easy to assemble and disassemble.

[0032] Preferably, the housing may have two cover elements positioned perpendicular to each other in the first and second directions. The cover element may preferably be designed to be positively connected to the rest of the housing. It is particularly preferred that the cover element has a fastening element corresponding to the fastening element of the base plates, for example, a hook or an eyelet. This makes assembly of the battery module particularly easy. In particular, it allows the battery cells and counter plates to be easily inserted into the housing formed by the base plates and the connecting elements using springs, and then the cover elements to be attached, with the battery cells and counter plates being secured by springs.

[0033] Preferably, the cover elements may have electrical contacts for the battery cells on the inside of the housing. This allows the battery cells to be contacted directly and securely within the housing, reducing wiring effort, simplifying assembly, and ensuring a reliable electrical connection. Preferably, the contacts may be arranged in slots in the cover elements. This provides additional fixation for the battery cells within the battery module. Furthermore, it is preferable for the contacts to be interconnected within the cover element.This allows for a compact and integrated electrical circuit within the housing, reducing wiring effort, simplifying assembly, and enabling more reliable and mechanically robust electrical connections. In particular, it allows multiple battery cells to be easily connected in series or parallel without the need for complex internal wiring.

[0034] Preferably, the cover elements may have electrical contacts on the outside of the housing. This allows the battery module to be easily integrated into a battery assembly and makes contact particularly simple. Furthermore, it enables a simple and standardized external connection of the battery module, thereby reducing installation effort, improving compatibility with various systems, and ensuring a reliable external electrical connection. Preferably, the cover element may also include electrical control and diagnostic elements. For example, a computer chip may be integrated into the cover element. This enables precise condition diagnostics, optimized battery management, and improved safety.

[0035] In a first alternative embodiment, it is preferably provided that the battery module is designed for use with a base cooling plate. It can be provided that at least one connecting element and / or at least one base plate is contactable with a base cooling plate, in particular a connecting element. This allows for particularly easy temperature control of the battery module. By contacting the base cooling plate with a connecting element or a base plate, the plate is cooled. The temperature is then transferred to the battery cells accordingly via the thermal conductivity of the housing components used. It is particularly preferable that a thermally conductive paste is arranged between the base cooling plate and the contacted housing component. This improves the heat transfer from the plate to the battery module.

[0036] In a second alternative embodiment, it is preferable that the battery module is designed for use with immersion cooling. In this embodiment, the housing may be designed to allow a cooling fluid to flow through it, with the battery cells being at least partially surrounded by the cooling fluid. It is particularly preferable that the battery module be immersed in a cooling fluid. This achieves particularly efficient heat dissipation, thereby minimizing temperature differences within the battery module, improving thermal stability, and extending the service life of the battery cells, while the complete or partial flow of the cooling fluid ensures uniform temperature distribution and prevents hotspots.

[0037] Preferably, the battery module may have a gap between the battery cells and the connecting element and / or the deflectable spring. This allows cooling fluid to flow past the sides of the battery cells, resulting in particularly good temperature control.

[0038] Preferably, the cover element may have fluid passages. This allows cooling fluid to be directed into and out of the battery module. In particular, the fluid passages may be designed to open into the space between the battery cells and the connecting element and / or deflectable spring. This advantageously allows the cooling fluid to be directed precisely past the battery cells, resulting in optimal temperature control of the battery module.

[0039] Preferably, cooling fluid is arranged between the first and second counter plates. The cooling fluid between the counter plates is designed so that it does not significantly bypass the battery cells. Essentially, the cooling fluid between the counter plates is not exchanged by the cooling fluid flow. This ensures that the cooling fluid is only directed to the battery cells at the points with the best heat exchange. As a result, temperature control can be particularly efficient, requiring a very low cooling fluid flow rate. Despite this efficiency, the space between the counter plates can be filled with cooling fluid, eliminating the need for special sealing. This allows for a simpler battery module design.

[0040] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention, either individually or in combination. The drawings show:

[0041] Fig. 1 schematically shows a housing part of an embodiment of a battery module according to the invention.

[0042] Fig. 2 schematically shows a counter plate with spring of an embodiment of a battery module according to the invention.

[0043] Fig. 3 schematically shows a partial section of an embodiment of a battery module according to the invention in a perspective view; Fig. 4 schematically shows a cross-section of a first alternative embodiment of a battery module according to the invention with a bottom cooling plate.

[0044] Fig. 5 schematically shows a cross-section of a second alternative embodiment of a battery module according to the invention with immersion cooling, and

[0045] Fig. 6 schematically shows another cross-section of the second alternative embodiment of the battery module according to the invention with immersion cooling.

[0046] Fig. 1 schematically shows a housing part of an embodiment of a battery module 10 according to the invention, wherein the housing 12 comprises a first base plate 18 and a second base plate 20 opposite the first base plate 18 in a first direction. The first base plate 18 is substantially parallel to the second base plate 20. The housing 12 has two connecting elements 22 opposite each other in a second direction, each connecting an edge of the first base plate 18 to an edge of the second base plate 20. The connecting elements 22 and the first and second base plates 18 / 20 are integrally manufactured from a single sheet of metal. The connecting elements 22 and the first and second base plates 18 / 20 each have a substantially rectangular shape.Furthermore, the first and second base plates 18 / 20 each have fastening elements 24 on edges opposite them perpendicular to the first and second directions, which are designed to secure a housing cover in a form-fitting manner.

[0047] Fig. 2 schematically shows a counter plate 26 / 28 with spring 30 of an embodiment of a battery module 10 according to the invention. The counter plate 26 / 28 can be used as the first counter plate 26 and as the second counter plate 28. The counter plate is made of a metal sheet and has a substantially rectangular shape. The counter plate 26 / 28 has a spring 30, which is deflectable in the first direction, at two opposite points. The spring 30 is integrally connected to the counter plate and is made of a metal sheet with several elongated recesses 32, each of which extends obliquely in its longitudinal direction relative to the first direction.

[0048] Fig. 3 schematically shows a partial section of an embodiment of a battery module 10 according to the invention in a perspective view. The battery module 10 comprises the housing part from Fig. 1 and two counter plates 26 / 28 from Fig. 2. The battery module 10 has a first battery cell 14 arranged in the housing 12, which in this case consists of three individual pouch cells. Furthermore, the battery module has a second battery cell 16 arranged in the housing 12, which also consists of three individual pouch cells. The first battery cell 14 contacts the first base plate 18 and the second battery cell 16 contacts the second base plate 20. Two of the counter plates 26 / 28 shown in Fig. 2 are arranged in the housing between the first and second battery cells 14 / 16 such that the first battery cell 14 contacts the first counter plate 26 and the second battery cell 16 contacts the second counter plate 28.The first and second counter plates 26 / 28 are spaced apart from each other and attached to the housing via springs 30. Additionally, the battery module 10 has a cover element 34, of which only the rear cover element 34 is shown.

[0049] Fig. 4 schematically shows a cross-section of a first alternative embodiment of a battery module 10 according to the invention with a base cooling plate 36. The cross-section extends through the battery module 10 along the first and second directions. The battery module 10 again comprises a housing 12, a first battery cell 14 arranged in the housing 12, and a second battery cell 16 arranged in the housing 12. In this case, the first and second battery cells 14 / 16 each consist of two individual pouch cells. The housing 12 has a first base plate 18 and a second base plate 20 opposite the first base plate 18 in a first direction, wherein the first base plate 18 is arranged substantially parallel to the second base plate 20, and wherein the housing 12 has two connecting elements 22 opposite each other in a second direction, each connecting an edge of the first base plate 18 to an edge of the second base plate 20.The first battery cell 14 contacts the first base plate 18, and the second battery cell 16 contacts the second base plate 20. The first battery cell 14 contacts a first counter plate 26 arranged between the first and second battery cells 16, and the second battery cell 16 contacts a second counter plate 28 arranged between the first and second battery cells 14. The first and second counter plates 26 / 28 are separated from each other and are each attached to the housing 12 at two opposite points by a spring 30 that can be deflected in the first direction. The battery module 10 is designed such that it can be contacted with a base cooling plate 36. In this configuration, a connecting element 22 is connected to the base cooling plate 36. A thermally conductive paste 38 is arranged between the base cooling plate 36 and the connecting element 22.

[0050] Fig. 5 schematically shows a cross-section of a second alternative embodiment of a battery module 10 according to the invention with immersion cooling. The cross-section runs along the first and second directions through the battery module 10 and is analogous to the view in Fig. 4, wherein the first and second battery cells 14 / 16 each consist of three individual pouch cells in this case. In particular, the battery module 10 has a gap 40 between the battery cells and the connecting element 22 and the deflectable spring 30. When the battery module 10 is immersed in a cooling fluid, these gaps 40, as well as the gap between the first and second counter plates 26 / 28, are filled with cooling fluid. The cooling fluid can then be guided past the battery cells 14 / 16 through the gaps 40. The cooling fluid between the counter plates 26 / 28 is not substantially exchanged, which allows the volume flow of the cooling fluid to be kept particularly low.

[0051] Fig. 6 schematically shows a different cross-section of the second alternative embodiment of the battery module 10 with immersion cooling according to the invention from Fig. 5. The cross-section runs parallel to the connecting elements (not shown) and perpendicular to the second direction. Compared to Fig. 5, the cover elements 34, which are positively connected to the remaining housing 12, are particularly visible. It can also be seen that the counter plates 26 / 28 are positively connected to the housing 12 at the cover elements 34 in the direction of the first direction. The cover elements 34 have fluid passages 42 through which cooling fluid can be introduced into and out of the battery module 10 in such a way that it can be guided past the battery cells 14 / 16 through the gap between the battery cells 14 / 16 and the connecting element (not shown).

[0052] Battery module

[0053] Housing

[0054] first battery cell

[0055] second battery cell

[0056] first base plate

[0057] second base plate

[0058] Connecting element

[0059] Fastener

[0060] first counter plate

[0061] second counter plate

[0062] Feather

[0063] cutouts

[0064] Cover element

[0065] Base cooling plate

[0066] thermally conductive paste

[0067] Distance

[0068] Fluid passages

[0069] Electrical contacts

Claims

Patent claims 1. Battery module (10) comprising a housing (12), a first battery cell (14) arranged in the housing (12) and a second battery cell (16) arranged in the housing (12), wherein the housing (12) comprises a first base plate (18) and a second base plate (20) opposite the first base plate (18) in a first direction, wherein the first base plate (18) is substantially parallel to the second base plate (20), wherein the housing (12) has two connecting elements (22) opposite each other in a second direction, each connecting an edge of the first base plate (18) with an edge of the second base plate (20), wherein the first battery cell (14) contacts the first base plate (18) and the second battery cell (16) contacts the second base plate (20), wherein the first battery cell (14) contacts a first counter plate (26) arranged between the first and second battery cells (16) and the second battery cell (16) contacts a second counter plate (28) arranged between the first and second battery cells (14), wherein the first and second counter plates (26, 28) are spaced apart from each other, and wherein the first and second counter plates (26, 28) are each attached to the housing (12) at two opposite areas via a spring (30) which can be deflected in the first direction.

2. Battery module (10) according to claim 1, wherein the battery cells (14, 16) are selected from prismatic cells and pouch cells, wherein the battery cells (14, 16) are particularly preferably pouch cells.

3. Battery module (10) according to claim 1 or 2, wherein at least one of the opposing connecting elements (22) is integrally formed with at least one of the base plates (18, 20).

4. Battery module (10) according to any one of claims 1 to 3, wherein the spring (30) is a metal sheet extending along an edge of the first and / or second counter plate (26, 28) and is configured parallel to the opposing connecting elements (22).

5. Battery module (10) according to claim 4, wherein the metal sheet of the spring (30) has several elongated recesses (32) which extend obliquely in their longitudinal direction to the first direction.

6. Battery module (10) according to one of claims 1 to 5, wherein the springs (30) are each integrally designed with the first and / or second counter plate (26, 28).

7. Battery module (10) according to one of claims 1 to 6, wherein the housing (12) has two cover elements (34) opposite each other perpendicular to the first and second directions.

8. Battery module (10) according to one of claims 1 to 7, wherein the battery module (10) is designed for use with a base cooling plate (36), wherein preferably at least one connecting element (22) and / or at least one base plate (18, 20) is contactable with a cooling plate (36), in particular a connecting element (22).

9. Battery module (10) according to one of claims 1 to 7, wherein the battery module (10) is designed for use with immersion cooling, wherein the housing (12) is designed to be permeated by a cooling fluid, wherein the battery cells (14, 16) are at least partially surrounded by the cooling fluid.

10. Battery module (10) according to one of claims 1 to 9, wherein the battery module (10) has a distance (40) between the battery cells (14, 16) and the connecting element (22) and / or the deflectable spring (30).

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