Traction battery for a motor vehicle that is at least partially electrically powered, and spare parts.

Abstract

A traction battery (1) with cell stacks (2) and a battery housing (3) with adjacent receiving spaces (5) separated from each other by housing walls (4). Each receiving space (5) can accommodate a cell stack (2). The cell stacks (2) have variable volumes due to operational conditions, such that pulsating forces (22) emanate from the cell stacks (2) and act on the housing walls (4). In at least one receiving space (5), a substitute body (6) is arranged instead of a cell stack (2). The substitute body (6) is suitable and designed to absorb the pulsating forces (22) emanating from a cell stack (2) in an adjacent receiving space (5) and to transmit them to an opposite housing wall (4).

Description

The present invention relates to a traction battery according to the preamble of claim 1 and to a replacement body for use in a traction battery. To reliably absorb the swelling forces in such traction batteries, very robust battery housings with thick walls between the compartments are sometimes used. However, this results in a high weight, which in turn negatively affects the range of electric vehicles. Therefore, it is advantageous if the cell stacks and the receiving chambers are arranged so that the opposing fluctuating forces from adjacent receiving chambers act on the housing walls. This balances the fluctuating forces emanating from adjacent receiving chambers, preventing the housing walls from experiencing uneven stress. From DE 10 2020 207 800 B3, a traction battery is known with battery cells arranged side by side in a housing and at least one degassing channel arranged in the housing. The degassing channel is integrated into a degassing cell, which corresponds to the battery cells in terms of height and width. This allows the degassing cell to be used in the housing, for example, as an alternative to or in addition to a battery cell. In contrast, the object of the present invention is to provide an improved traction battery. In particular, the traction battery should be versatile. For example, different power outputs of the traction battery should be achievable with minimal design and development effort. Preferably, the traction battery should also be weight-optimized. This problem is solved by a traction battery with the features of claim 1. A replacement body according to the invention is the subject of claim 11. Preferred embodiments of the invention are the subject of the dependent claims. Further advantages and features of the present invention will become apparent from the general description and the description of the exemplary embodiment. The traction battery according to the invention is intended for a motor vehicle that is at least partially electrically powered, and in particular for an electric vehicle and / or hybrid vehicle. The traction battery comprises cell stacks, each with an arrangement of battery cells (arranged or stacked in a stacking direction). The traction battery comprises at least one battery housing. The battery housing comprises receiving spaces arranged side by side and separated from one another by housing walls. In particular, the battery housing comprises at least three and preferably at least four or more receiving spaces. At least one (only one) cell stack can be arranged in each of the receiving spaces. In particular, the cell stacks have volumes that vary due to operational conditions, so that pulsating forces emanate from the cell stacks (each) and act on the housing walls. In particular, the cell stacks exhibit an increase in volume due to operational conditions.In this arrangement, at least one replacement body is arranged in at least one receiving space. In particular, the at least one replacement body is arranged in place of at least one cell stack in the at least one receiving space. The replacement body is suitable and designed to absorb the fluctuating forces emanating from a cell stack in an adjacent receiving space (via the housing wall located between them) and to transmit them to an opposite housing wall (of a receiving space equipped with a cell stack). In particular, the replacement body serves as a replacement for at least one cell stack and, in particular, for exactly one cell stack. In particular, the replacement body is designed to be compression-resistant with respect to the fluctuating forces expected during intended operation. The present invention offers many advantages. A significant advantage is the replacement body with its mechanical properties for transmitting the swell forces. This makes it possible, according to the invention, to omit one or more cell stacks and instead arrange one or more replacement bodies in the receiving spaces. This allows the performance or capacity of the traction battery to be adjusted with minimal structural complexity. Thus, the traction battery is particularly flexible and can be used, for example, in different vehicles. With previously known battery concepts, the housing always had to be specifically designed for a particular battery output, or the walls of empty battery compartments had to be correspondingly thick to prevent deformation from swelling forces. In contrast, the invention allows for flexible configuration of the battery compartments while simultaneously optimizing weight. It is preferred and advantageous that the replacement body extends from one housing wall to an opposite housing wall. Preferably, the replacement body can thereby directly transmit a load or fluctuating force acting on one housing wall (in the direction of the replacement body) to the opposite housing wall. In particular, the replacement body is supported against opposite housing walls. Preferably, the replacement body (in the longitudinal direction of the battery housing and / or in the longitudinal direction of the receiving space) can be inserted into a free receiving space and is preferably slid in. In particular, the replacement body can be inserted into the receiving space analogously to a cell stack. In particular, the cell stacks can be inserted into a free receiving space in the longitudinal direction of the battery housing. In a particularly advantageous embodiment, the battery housing comprises at least one extruded profile or is designed as such. Preferably, the housing walls are provided by profile walls integrally connected to one another. Preferably, the receiving spaces are provided by profile cavities. In particular, the extruded profile comprises profile walls that are integrally connected to one another and at least partially enclose the receiving spaces. In particular, the housing walls enclose the receiving spaces at least on their longitudinally extending sides. For example, the extruded profile is an extruded profile or a continuously cast profile. In a battery housing designed as an extruded profile, changes to the number of cavities are particularly complex and can generally only be achieved through the development of new tooling for manufacturing the profile. This makes modifications, for example to adjust the power output or capacity, usually very expensive. Omitting cell stacks in the cavities leads to uneven stresses on the profile walls, which must be compensated for with complex changes to the wall thickness. Crossbeams in the cavities are also difficult or impossible to implement in extruded profiles. Therefore, the present invention offers numerous advantages when used in combination with such battery housings. In particular, the extruded profile completely encloses the receiving spaces. In particular, the extruded profile is closed in the circumferential direction. In particular, the profile walls run parallel to the longitudinal direction of the extruded profile. In particular, the extruded profile is open at its longitudinal ends (due to the manufacturing process). In particular, the end faces of the extruded profile are open. The end faces are located, in particular, at the axial ends of the extruded profile. Preferably, the battery housing comprises end walls that serve to close the end faces of the extruded profile. In particular, one or both end faces are closed after the cell stacks and the replacement body have been inserted. Specifically, the cell stacks or the replacement body can be inserted into the profile cavities of the extruded profile from at least one open end face. The profile walls of the extruded profile are manufactured in a single primary forming process. The extruded profile is formed in one piece. The end faces can be closed by means of (separately manufactured) end walls. The profile walls form the partitions, the outer walls, and preferably also the base and the lid of the battery housing. The partitions, outer walls, and base / lid are joined together in one piece. In an advantageous embodiment, the traction battery comprises at least one cooling device. In particular, the cooling device is suitable and designed to cool the cell stacks or their battery cells directly by means of a liquid coolant flowing through the receiving chambers (so-called direct cooling). Preferably, the replacement body is designed with respect to the displacement of the coolant corresponding to the cell stack that the replacement body is intended to replace. This allows one or more cell stacks to be omitted without requiring any modifications to the cooling system. For example, despite the omitted cell stacks, no additional coolant is needed, and the cooling performance is even improved. The present invention can be used particularly advantageously in traction batteries with so-called direct cooling. Cooling, in this context, refers specifically to temperature control, so that targeted heating of the cell stacks via the coolant is also possible. In particular, the replacement body has a displacement that is equal to the displacement of the cell stack under a defined operating condition of the traction battery or under a defined volume state of the cell stack. Specifically, the battery cells, the replacement body, and especially the housing walls are directly exposed to the liquid coolant. Preferably, the replacement body is designed to be coolant-tight. In particular, the replacement body does not absorb the coolant. Specifically, the replacement body is made of a material that does not absorb the coolant. In particular, the battery housing is sealed to be coolant-tight. It is preferred and advantageous that the replacement body is lighter than the cell stack it is intended to replace. This allows not only the performance or capacity of the traction battery to be adjusted by omitting the cell stack, but also its weight to be optimized. In particular, the replacement body is lighter than the coolant (for the same volume). Preferably, the replacement body is formed in one piece. This allows for particularly easy handling and manufacturing. A one-piece replacement body can be used particularly advantageously with the previously described extruded profile. The replacement body can also be formed in multiple parts. In this way, the individual parts can be inserted into a receiving space. In particular, the individual parts are formed as one-piece blocks or segments. The replacement body is preferably made of a particularly compression-resistant plastic material. Preferably, the replacement body comprises expanded polypropylene or polyethylene, or a rigid polyurethane foam, or is made of such a material. Other compression-resistant plastic materials are also possible. The plastic material may contain reinforcing fibers. In particular, the housing walls run parallel to each other, at least between the receiving spaces, and preferably transversely to the stacking direction of the battery cells in the cell stacks. This preferably results in opposing fluctuating forces from adjacent receiving spaces acting on the housing walls. In particular, the replacement body can absorb and transmit these opposing fluctuating forces. Specifically, the housing walls run transversely to the fluctuating forces acting in the stacking direction. Such a design is particularly advantageous because the greatest fluctuating forces generally occur in the stacking direction. The replacement body according to the invention is intended for use in a traction battery as described herein. The replacement body also solves the problem of the invention particularly advantageously. The right to claim the use of a replacement body with a traction battery according to the invention is reserved. The traction battery is, in particular, a high-voltage battery. The battery housing is, in particular, a modular housing. Specifically, the traction battery comprises several battery modules, each of which contains a module housing. The capacity or power of the traction battery is, in particular, adjustable by the number of compartments containing cell stacks. The increase in volume due to operation is, in particular, caused by the state of charge, age, and / or cell breathing. A housing wall, in particular, runs between two adjacent recording spaces. The housing walls, in particular, each have at least one wall or are double-walled or multi-walled. The housing walls include, in particular, partition walls and outer walls. The partition walls are, in particular, the housing walls that run between the adjacent recording spaces. The partition walls can be identical or partially different. The outer walls are, in particular, the housing walls that enclose the outer recording spaces. In particular, the battery housing comprises at least one base and / or at least one cover, between which the housing walls extend. In particular, the battery housing comprises transverse walls, which are arranged transversely to the housing walls and, in particular, extend in the stacking direction. The transverse walls can also be referred to as end walls. The replacement body is designed separately from the battery housing. The replacement body can be inserted as a separate component into a (free) receiving space. The replacement body is a structurally effective component. The replacement body is necessary to maintain the structural integrity of the battery housing. Specifically, the receiving body must be inserted into a receiving space to maintain structural integrity if no cell stack is present. The replacement body has, in particular, a basic geometry that corresponds to a basic geometry of the cell stack. Specifically, the width, length, and / or height of the replacement body are modeled on the basic geometry of the cell stack. The replacement body also has, in particular, a cross-sectional profile that corresponds to a cross-sectional profile of the cell stack. These specifications refer specifically to the cell stack that the replacement body is intended to replace. Preferably, the basic geometry and / or the cross-sectional profile of the replacement body also corresponds to an internal geometry and / or a cross-sectional profile of the receiving space in which the replacement body can be inserted. Further advantages and features of the present invention will become apparent from the exemplary embodiments, which are explained below with reference to the accompanying figures. Figure 1 shows a purely schematic representation of a traction battery according to the invention in a cross-sectional view. Fig. 1 shows a traction battery 1 according to the invention for supplying energy to an electric drive system of an electric vehicle or a hybrid vehicle. The traction battery 1 comprises a battery housing 3 with several adjacent receiving compartments 5 for enclosing cell stacks 2. Housing walls 4, designed as partitions 14, extend between the receiving compartments 5. The outer receiving chambers 5 are closed off on their longitudinal sides by housing walls 4, which are designed as outer walls 24. In addition to the housing walls 4, the battery housing 3 also includes a base 44 and a cover 34. The axial ends or end faces can be closed by end walls not shown here. The cell stacks 2 each comprise an arrangement of battery cells 12, which are lined up side by side along a stacking direction 32. For clarity, only some of the battery cells 12 are indicated here by dashed lines. The traction battery 1 includes a cooling unit 8, which is designed as a so-called direct cooling system. A liquid coolant flows directly through the receiving chambers 5, so that the cell stacks 2 contained therein, or rather their battery cells 12, are directly surrounded by the coolant. The cooling unit 8 also includes other components not shown here, such as a coolant pump. During operation of the traction battery 1, the cell stacks 2 can undergo a change in volume. This causes the battery cells 12 to swell, resulting in swelling forces 22 that act on the battery housing 3. The greatest swelling forces 22 occur in the stacking direction 32 of the battery cells 12. These swelling forces 22 are indicated here by a double arrow. When all receiving compartments 5 are filled with cell stacks 2, the swelling forces 22 balance each other out, so that there is no one-sided loading of the partitions 14. To enable simple and weight-optimized performance adjustment of the traction battery 1 when needed, the traction battery 1 includes one or more replacement bodies 6. This makes it possible to omit one or more cell stacks 2 if required. The resulting freed-up mounting spaces 5 are then each fitted with a replacement body 6. In the example shown here, one such replacement body 6 is located in one of the mounting spaces 5. The replacement body 6 can absorb the fluctuating forces 22 acting on one housing wall 4 and transfer them directly to the opposite housing wall 4. This load transfer 16 is indicated here by a hatched double arrow. The replacement body 6 has a basic geometry that corresponds to the basic geometry of the cell stack 2, for which the replacement body 5 is intended. Furthermore, the replacement body 6 displaces the same amount of coolant 18 as the omitted cell stack 2. Therefore, no additional coolant 18 is required. In addition, the replacement body 6 is lighter than both the coolant 18 and the omitted cell stack 2. In an advantageous embodiment, the battery housing 3 is designed as an extruded profile 7, for example, as an extruded profile or a continuously cast profile. The housing walls 4, as well as the base 44 and the cover 34, are then provided by profile walls 17 of the extruded profile 7. The profile walls 17 are integrally connected to one another. Due to the manufacturing process, the end faces of the extruded profile 7 are open and can be closed by end walls (not shown here). Profile cavities 27 are formed within the extruded profile 7, into which the cell stacks 2 or the replacement body 6 can be inserted longitudinally. Reference symbol list: 1 Traction battery 2 Cell stack 3 Battery housing 4 Housing wall 5 Receptacle 6 Spare body 7 Extruded profile 8 Cooling unit 12 Battery cell 14 Partition 16 Load transfer 17 Profile wall 18 Coolant 22 Swell force 24 Outer wall 27 Profile cavity 32 Stacking direction 34 Cover 44 Base

Claims

Traction battery (1) for a motor vehicle that is at least partially electrically powered, comprising cell stacks (2) each with an arrangement of battery cells (12) and at least one battery housing (3) with receiving spaces (5) arranged side by side and separated from each other by housing walls (4), wherein at least one cell stack (2) can be arranged in each of the receiving spaces (5) and wherein the cell stacks (2) have volumes that vary depending on operation, such that pulsating forces (22) emanate from the cell stacks (2) which act on the housing walls (4), characterized in that at least one substitute body (6) is arranged in at least one receiving space (5) instead of a cell stack (2) and that the substitute body (6) is suitable and designed to absorb the pulsating forces (22) emanating from a cell stack (2) in an adjacent receiving space (5) and to transmit them to an opposite housing wall (4). Traction battery (1) according to the preceding claim, wherein the replacement body (6) extends from one housing wall (4) to an opposite housing wall (4), so that the replacement body (6) can transfer a load acting on one housing wall (4) directly to the opposite housing wall (4). Traction battery (1) according to one of the preceding claims, wherein the replacement body (6) can be inserted into a free receiving space (5). Traction battery (1) according to one of the preceding claims, wherein the battery housing (3) comprises at least one extruded profile (7) and wherein the housing walls (4) are provided by integrally connected profile walls (17) and the receiving spaces (5) are provided by profile cavities (27). Traction battery (1) according to one of the preceding claims, comprising a cooling device (8) in which the battery cells (12) are cooled directly by a liquid coolant (18) flowing through the receiving spaces (5), wherein the replacement body (6) is designed in terms of the displacement of the coolant (18) corresponding to the cell stack (2) which it is intended to replace. Traction battery (1) according to one of the preceding claims, wherein the replacement body (6) is designed to be coolant-tight. Traction battery (1) according to one of the preceding claims, wherein the replacement body (6) is lighter than the cell stack (2) which it is intended to replace. Traction battery (1) according to one of the preceding claims, wherein the replacement body (6) is formed in one piece. Traction battery (1) according to one of the preceding claims, wherein the replacement body (6) is made of a particularly pressure-resistant plastic material and preferably comprises expanded polypropylene or polyethylene or a rigid polyurethane-based foam. Traction battery (1) according to one of the preceding claims, wherein the housing walls (4) extend parallel to each other and transversely to the stacking direction (32) of the battery cells (12) in the cell stacks (2) at least between the receiving spaces (5), such that opposing pulsating forces (22) from adjacent receiving spaces (5) act on the housing walls (4). Replacement body (6) for use in a traction battery (1) according to one of the preceding claims.

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