Battery with swelling compensation
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-08-13
Smart Images
Figure DE2025101170_13082026_PF_FP_ABST
Abstract
Description
[0001] P241335
[0002] - 1 - Battery with threshold compensation
[0003] The invention relates to a battery with swelling compensation.
[0004] 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 (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 as the battery ages, again particularly pronounced in the stacking direction of the electrodes (irreversible "swelling").
[0005] When designing batteries, swelling properties must be taken into account to prevent damage to surrounding components. Furthermore, volume changes caused by electrode swelling or breathing can lead to mechanical stresses that affect battery performance and lifespan. To counteract these effects, some batteries incorporate swelling compensation elements, which can be designed differently depending on the specific requirements.
[0006] DE 102018204220 A1 describes a battery comprising a fully enclosed frame containing at least one battery cell with a plurality of parallel stacked electrodes and a pressure device by which the electrodes can be pressurized. A medium can be supplied to or discharged from the pressure device via an interface, in particular an elastic pressure medium such as a hose or bladder. P241335
[0007] -2 - DE 11 2010005063 T5 describes a modular high-voltage battery with a housing, with battery cells arranged in it, and with a compression bladder that can be pressurized.
[0008] DE 102020005583 A1 discloses an electrical energy storage device with at least one electrode stack and at least one pressure compensation device in the form of a hose-like air spring. An electronic processing unit is provided for controlling the at least one pressure compensation device, which is designed to exert pressure on the electrode stack depending on its respective thickness.
[0009] 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.
[0010] There is a constant need to improve the swelling compensation of batteries, especially immersion-cooled batteries.
[0011] Based on this situation, the present task is to provide a battery with improved swelling compensation, which is particularly suitable for immersion-cooled batteries.
[0012] The problem is solved according to the invention by a battery cell having the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims and the following description, each of which, individually or in combination, can represent an aspect of the invention. P241335
[0013] - 3 - The problem is therefore solved by a battery comprising a housing and a stacking arrangement arranged in the housing comprising several battery cells stacked in a first direction,
[0014] wherein the battery comprises at least one irreversibly compressible first element for irreversible swelling compensation and at least one reversibly compressible second element for reversible swelling compensation,
[0015] wherein the first element for irreversible swelling compensation comprises at least one first compensation body encompassed by the stacking arrangement, wherein the first compensation body is irreversibly compressible at least in the first direction, and wherein the first compensation body is filled with a first fluid that is not in contact with the interior of the housing,
[0016] wherein the second element for reversible swelling compensation comprises at least one second compensation body encompassed by the stack arrangement, wherein the second compensation body is reversibly compressible at least in the first direction.
[0017] The battery, therefore, comprises within its housing—in particular, an immersion-cooled housing, i.e., one through which cooling fluid flows—a stack of battery cells, as well as the compensation elements of at least two components for swelling compensation. An irreversibly compressible first component is provided to compensate for irreversible swelling (age-related swelling), and a reversibly compressible second component is provided to compensate for reversible swelling (breathing, SoC-dependent swelling). By dividing the swelling compensation into two separate components, it is possible to better adapt the respective components to the swelling being compensated. In particular, the specific design of the two components surprisingly makes it possible to accommodate only a portion of the volume displaced during battery swelling in order to compensate for the necessary volume during subsequent shrinkage.This swelling is absorbed by the reversibly compressible second compensatory body, which displaces and absorbs a corresponding volume. Age-related swelling is compensated for by irreversibly compressing the first compensatory body, which is filled with the first fluid. The separation of the first elements from the second elements allows the displaced volume to be treated differently (P241335).
[0018] - 4 - can be less than the volume displaced during reversible swelling. Surprisingly, it was shown that the volume to be captured can even be less than half the total volume displaced over time, resulting in significant savings potential. This is particularly relevant for immersion-cooled batteries.
[0019] For the purposes of the present invention, a housing can be understood to be a flexible or rigid, as well as closed or open, receptacle for the stacking arrangement. The housing can also be arranged within a further housing, which may, for example, be rigid and / or closed.
[0020] The following sections explain advantageous aspects and subsequently describe preferred modified embodiments. Explanations, particularly regarding advantages and definitions of features, are essentially descriptive and preferred, but not limiting, examples. If an explanation is limiting, this will be explicitly stated.
[0021] Preferably, the battery may be provided with immersion cooling. For the purposes of the present invention, immersion cooling can be understood to mean, in particular, that the battery cells of the stacked arrangement are at least partially surrounded by a cooling fluid.
[0022] In a preferred embodiment, the battery may have a reservoir for the cooling fluid, the reservoir being designed to collect any cooling fluid displaced during swelling. In an alternative preferred embodiment, the battery may not have a reservoir for the cooling fluid. It has been shown that the proposed battery displaces particularly little cooling fluid during cell swelling because reversible swelling accounts for only a small portion of the volume changes and can be compensated for, if necessary, by a pressure increase within the battery. Furthermore, irreversible, age-related swelling can be compensated for by the first compensating element in such a way that no additional cooling fluid needs to be displaced. This, in particular, eliminates the need for additional reservoirs.
[0023] - 5 - can be saved or kept comparatively small. In addition, this can result in less cooling fluid being required overall.
[0024] Preferably, the first fluid is a gas or a liquid, wherein the first fluid is preferably nitrogen or air, preferably dried nitrogen or dried air, or wherein the liquid is preferably an organic dielectric fluid, preferably an oil. This makes it possible to handle the fluid particularly well.
[0025] Preferably, the first compensating element is a bag filled with the first fluid. This makes it particularly easy to manufacture the first compensating element and allows it to be compressed well in the first direction.
[0026] In a first alternative embodiment, the first compensating body can be fluidically sealed. Preferably, the first compensating body can be designed to undergo irreversible plastic deformation, essentially perpendicular to the first direction, when compressed. This allows the first compensating body to become thinner during swelling in the first direction, compressing the first fluid without it coming into contact with the interior of the housing. This also ensures that swelling results in no or a comparatively smaller pressure increase in the first direction, thereby improving the battery's lifespan. It should be noted that in this embodiment, a corresponding volume can be displaced laterally from the stacked arrangement, and in the case of an immersion-cooled battery, this will consequently displace a corresponding amount of cooling fluid.
[0027] Preferably, in this embodiment, the first fluid can be a gas. This ensures that, during irreversible compression of the first compensating body, the volume of the compensating body is at least partially reduced by compression of the gas. Advantageously, this allows for the possibility that a [missing information], which may be used for immersion cooling, can be [missing information].
[0028] - 6 -th cooling fluid is displaced only in particularly small quantities and must therefore be collected or kept in reserve.
[0029] In a second alternative embodiment, it can be provided that the first compensation body is fluidically connected to a volume outside the housing via a fluid connection in order to permanently drain the first fluid from the first compensation body.
[0030] This advantageously ensures that the first fluid displaced during compression of the first compensating body is controlled and ultimately discharged into an external volume. This can reduce the pressure load within the housing as age-related swelling increases and, particularly in immersion-cooled batteries, prevents the displacement of cooling fluid.
[0031] Preferably, in this embodiment, the first fluid can be a gas such as nitrogen or air. This allows the first fluid to be discharged into the environment via the fluid connection, eliminating the need for a collection container.
[0032] Alternatively, and preferably, in this embodiment the first fluid can be a liquid, such as an organic oil. In this case, a container for collecting the first fluid can be provided outside the housing. This can result in less of the potentially more expensive cooling fluid being required, particularly in immersion-cooled batteries.
[0033] Preferably, the fluid connection may include a valve in the form of a pressure relief valve or an electronically controlled one-way valve.
[0034] This ensures that the first compensatory body is compressed only under controlled conditions. Specifically, it allows the first compensatory body to be compressed only when a certain degree of swelling is exceeded, which is otherwise compensated for by the second compensatory bodies. Thus, compression is only required in the case of irreversible swelling, or swelling that exceeds the reversible compression that occurred during loading.
[0035] - 7 - As the swelling progresses, the first fluid is drained through the fluid connection. This ensures that the battery can be operated under virtually the same pressure conditions during charging and discharging, even after aging, which can significantly extend the battery's lifespan.
[0036] Preferably, the second compensation body may be filled with a second fluid that is not in contact with the interior of the housing, wherein the second compensation body is fluidically sealed.
[0037] It is preferable that the second compensating body expands elastically, essentially perpendicular to the first direction, when compressed. This allows the second compensating body to become thinner during swelling in the first direction, enabling the second fluid to be forced out of the stacked assembly without coming into contact with the interior of the housing. In particular, this also prevents or significantly reduces the pressure increase in the first direction during swelling, thereby improving the battery's lifespan. It should be noted that in this embodiment, a corresponding volume of the second compensating body is displaced into a space to the side of the stacked assembly, and in the case of an immersion-cooled battery, this displaces the corresponding cooling fluid.
[0038] Preferably, in this embodiment, the second fluid can be a gas. This ensures that comparatively less fluid is forced out of the stacked arrangement when the second compensating body is compressed, because the volume of the second compensating body is at least partially reduced by the compression of the second fluid in gaseous form. Advantageously, this means that any cooling fluid used for immersion cooling is displaced only in very small quantities and therefore needs to be collected or stored accordingly. Alternatively, in this embodiment, the second fluid can be a liquid, for example, an oil. P241335
[0039] - 8 - Preferably, the second compensating body may include a foam pad. The second compensating body is, in particular, elastically deformable, so that it can be reversibly deformed during swelling or breathing.
[0040] This allows the restoring force for the second compensating element to be set depending on the degree of compression of the compensating element. This ensures that the battery's performance during swelling and breathing is particularly reproducible and controllable.
[0041] Preferably, the second compensating body is a bag filled with the second fluid. It is also preferably possible for the second compensating body to be a bag filled with the foam poster and the second fluid. It has been shown that this is particularly effective in compensating for reversible swelling, especially in immersion-cooled batteries.
[0042] Preferably, the first element for irreversible swelling compensation comprises several first compensation bodies encompassed by the stacking arrangement and / or the second element for reversible swelling compensation comprises several second compensation bodies encompassed by the stacking arrangement.
[0043] Preferably, the first element for irreversible swelling compensation comprises one or more first compensation bodies encompassed by the stack arrangement, wherein the number of first compensation bodies is preferably greater than or equal to 1, but less than or equal to the number of battery cells in the stack arrangement. With a small number of first compensation bodies, it is possible to design them particularly simply and to achieve a high fluid volume relative to their total volume. With a larger number of first compensation bodies, it is possible to minimize the displacement of the battery cells within the housing during irreversible swelling, thereby keeping mechanical stresses within the stack particularly low. P241335
[0044] - 9 - Preferably, the multiple first compensating elements are at least partially fluidically connected to one another in parallel or in series and are optionally fluidically connected to the volume outside the housing via the fluid connection. This can be understood to mean that multiple first compensating elements are fluidically connected to one another, such that compression of one of the first compensating elements also affects the other first compression elements connected to it. Optionally, the connected first compensating elements can then be fluidically connected to the volume outside the housing. This can, for example, make it possible to require only one one-way valve and, if necessary, a collection container for the first fluid.
[0045] Preferably, the second element for reversible swelling compensation comprises one or more second compensation bodies enclosed by the stack arrangement, wherein the number of second compensation bodies is preferably greater than or equal to 1, but less than or equal to the number of battery cells in the stack arrangement. With a small number of second compensation bodies, a particularly simple design can be achieved. With a larger number of second compensation bodies, the position of the battery cells in the housing shifts as little as possible during reversible swelling, thereby keeping mechanical stresses within the stack particularly low.
[0046] Preferably, the first compensating elements together comprise a first volume, and the second compensating elements together comprise a second volume, wherein the ratio of the first volume to the second volume is in a range of greater than or equal to 1:1 to less than or equal to 3:1, preferably in a range of greater than or less than 1.5:1 to less than or equal to 2.5:1, for example, 2:1. This preferably allows the first compensating elements to be used exclusively for compensating irreversible swelling, and the second compensating elements exclusively for compensating reversible swelling. In particular, the volume ratio in these ranges can be especially well adapted and optimized for the specific battery in question. P241335
[0047] - 10 -
[0048] 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:
[0049] Fig. 1a schematically shows an embodiment of a battery according to the invention, Fig. 1b schematically shows the embodiment from Fig. 1a with fluid connection to the outside,
[0050] Fig. 2a schematically shows another embodiment with several parallel connected first compensation bodies,
[0051] Fig. 2b schematically shows the embodiment from Fig. 2a with fluid connection to the outside,
[0052] Fig. 3a schematically shows an embodiment with several first compensation bodies connected in a series,
[0053] Fig. 3b schematically shows the first embodiment from Fig. 3a with fluid connection to the outside,
[0054] Fig. 4a schematically shows an embodiment with several second compensation bodies,
[0055] Fig. 4b schematically shows the embodiment from Fig. 4a with fluid connection to the outside,
[0056] Fig. 5a schematically shows an embodiment with several second compensation bodies and several first first compensation bodies connected in parallel,
[0057] Fig. 5b schematically shows the embodiment from Fig. 5a with fluid connection to the outside,
[0058] Fig. 6a schematically shows an arrangement of a first compensation body with fluid connection and a second compensation body with a foam pad in an initial state, and
[0059] Fig. 6b schematically shows the arrangement from Fig. 6a, where the arrangement has been compressed by reversible swelling. P241335
[0060] - 11 - The described embodiment is merely an example that can be modified and / or supplemented in various ways within the scope of the claims. Identical reference numerals in the figures denote identical components.
[0061] Fig. 1a schematically shows an embodiment of a battery 10 according to the invention, comprising a housing 12 and a stacked arrangement therein, comprising several battery cells 14 stacked in a first direction. The battery includes a first compensating body 16 as part of a first element for irreversible swelling compensation and a second compensating body 18 as part of a second element for reversible swelling compensation. The first compensating body 16 is irreversibly compressible at least in the first direction, which here runs in the direction of the arrow through the planes formed by the battery cells 14, and is filled with a first fluid that is not in contact with the interior of the housing 12. The irreversible compression is achieved by irreversible plastic deformation of the first compensating body 16, whereby the pressure in the first fluid located in the first compensating body 16 increases.The second compensation body 18 is elastically compressible in the first direction and returns to its original shape when the pressure decreases again.
[0062] Fig. 1b schematically shows the battery 10 from Fig. 1a, wherein the first compensating body 16 is fluidically connected via a fluid connection 20 to a volume 22 outside the housing 12. A valve 24 in the form of a pressure relief valve prevents the first fluid from flowing back into the first compensating body 16 once it has been forced out by irreversible compression. The volume 22 can be a collection container if the first fluid is a liquid, or simply the ambient atmosphere if the first fluid is a gas, such as air or nitrogen.
[0063] Fig. 2a schematically shows another embodiment of the battery 10 according to the invention, wherein several first compensation bodies 16 are fluidically connected to one another in parallel. The first compensation bodies 16 are arranged between the battery cells 14. P241335
[0064] - 12 - Fig. 2b schematically shows the battery 10 from Fig. 2a, wherein the first compensation bodies 16, which are fluidically connected in parallel to each other, are fluidically connected via a fluid connection 20 and a valve 24 in the form of a one-way valve with a volume 22 outside the housing 12.
[0065] Fig. 3a schematically shows an embodiment of the battery 10 according to the invention, wherein several first compensation bodies 16 are fluidically connected to one another in series. The arrangement of the first compensation bodies 16 is as shown in Fig. 2a between the battery cells 14.
[0066] Fig. 3b schematically shows the battery 10 from Fig. 3a, wherein the first compensation bodies 16, which are fluidically connected in series, are fluidically connected via a fluid connection 20 and a valve 24 in the form of a one-way valve with a volume 22 outside the housing 12.
[0067] Fig. 4a schematically shows an embodiment of the battery 10 according to the invention with several second compensation bodies 18. The second compensation bodies 18 are arranged between the battery cells 14.
[0068] Fig. 4b schematically shows the battery 10 from Fig. 4a, wherein the second compensation bodies 18 are fluidically connected via a fluid connection 20 and a valve 24 in the form of a one-way valve with a volume 22 outside the housing 12.
[0069] Fig. 5a schematically shows an embodiment of the battery 10 according to the invention with several second compensation bodies 18 and several first compensation bodies 16 connected to each other in parallel fluidically. The first compensation bodies 16 and second compensation bodies 18 are arranged between the battery cells 14.
[0070] Fig. 5b schematically shows the battery 10 from Fig. 5a, wherein the first compensating elements 16 are fluidically connected via a fluid connection 20 and a valve 24 in the form of a pressure relief valve with a volume 22 outside the housing 12.
[0071] - 13 - Fig. 6a shows schematically an arrangement of a first compensation body 16 with fluid connection 20 and a second compensation body 18 with a foam pad 26 in an initial state.
[0072] Fig. 6b schematically shows the arrangement from Fig. 6a, where the arrangement has been compressed by reversible swelling. The second compensating body 18 was compressed in the first direction and expanded perpendicular to the first direction, which is schematically represented by the lateral protrusions. P241335
[0073] - 14 - List of reference symbols
[0074] 10 batteries
[0075] 12 cases
[0076] 14 battery cells
[0077] 16 first compensation body
[0078] 18 second compensation body
[0079] 20 Fluid connection
[0080] 22 Volume outside the case
[0081] 24 valve
[0082] 26 foam pads
Claims
P241335 - 15 - Patent claims 1. Battery (10) comprising a housing (12) and a stacking arrangement arranged in the housing (12) comprising several battery cells (14) stacked in a first direction, wherein the battery (10) comprises at least one irreversibly compressible first element for irreversible swelling compensation and at least one reversibly compressible second element for reversible swelling compensation, wherein the first element for irreversible swelling compensation comprises at least one first compensation body (16) encompassed by the stack arrangement, wherein the first compensation body (16) is irreversibly compressible at least in the first direction, wherein the first compensation body (16) is filled with a first fluid which is not in contact with the interior of the housing (12), wherein the second element for reversible swelling compensation comprises at least one second compensation body (18) encompassed by the stack arrangement, wherein the second compensation body (18) is reversibly compressible at least in the first direction.
2. Battery according to claim 1, wherein the first fluid is a gas or a liquid, preferably wherein the first fluid is nitrogen or air, preferably dried nitrogen or dried air, or wherein the liquid is an organic dielectric liquid, preferably an oil.
3. Battery according to claim 1 or 2, wherein the first compensation body (16) is fluidically connected via a fluid connection (20) to a volume (22) outside the housing (12) in order to permanently drain the first fluid from the first compensation body (16).
4. Battery according to claim 3, wherein the fluid connection (20) comprises a valve (24) in the form of a pressure relief valve or an electronically controlled one-way valve. P241335 - 16 - 5. Battery according to one of claims 1 to 4, wherein the second compensation body (18) is filled with a second fluid which is not in contact with the interior of the housing (12), wherein the second compensation body (18) is fluidically sealed.
6. Battery according to one of claims 1 to 5, wherein the second compensation body (18) includes a reversibly compressible foam pad (26).
7. Battery according to any one of claims 1 to 6, wherein the first element for irreversible swelling compensation comprises several first compensation bodies (16) encompassed by the stacking arrangement.
8. Battery according to claim 7, wherein the several first compensation bodies (16) are at least partially fluidically connected in parallel or in series to each other and are fluidically connected to the volume (22) outside the housing (12) via the fluid connection (20).
9. Battery according to any one of claims 1 to 8, wherein the second element for reversible swelling compensation comprises several second compensation bodies (18) encompassed by the stack arrangement.
10. Battery according to any one of claims 1 to 9, wherein the first compensation bodies (16) together have a first volume and the second compensation bodies (18) together have a second volume, wherein the ratio of first volume to second volume is in a range of greater than or equal to 1:1 to less than or equal to 3:1, preferably in a range of greater than or less than 1.5:1 to less than or equal to 2.5:1, for example 2:
1.
11. Battery according to one of claims 1 to 10, wherein it is an immersion-cooled battery, the battery cells (14) of which are at least partially surrounded by a cooling fluid in the stack arrangement.