Traction battery of a motor vehicle

Abstract

Traction battery (10) of a motor vehicle, with a plurality of battery cells (12), wherein the battery cells (12) are arranged either in a battery housing (11) of the traction battery (10) or in battery module housings of battery modules of the traction battery (10) which are positioned in the battery housing (11), and wherein the battery cells (12) in the battery housing (11) or in the respective battery module housing are subjected to a clamping force via at least one clamping element (14).The respective clamping element (14) has a first clamping body (14a), a second clamping body (14b) and a swelling material (14c) arranged between the first clamping body (14a) and the second clamping body (14b), wherein the swelling material (14c) of the respective clamping element (14) swells when the swelling material (14c) comes into contact with a swelling agent (15), causes a relative movement between the first clamping body (14a) and the second clamping body (14b) of the respective clamping element (14) and thus applies a clamping force to at least one battery cell (12).

Description

[0001] The invention relates to a traction battery of a motor vehicle.

[0002] The structure of a traction battery in a motor vehicle is well known in practice. A traction battery comprises several battery cells. The battery cells are arranged either directly in a battery housing of the traction battery or indirectly in battery module housings of battery modules of the traction battery, which are positioned within the battery housing. It is known that a coolant flows around the battery cells to cool them.

[0003] DE 10 2021 212 887 A1 discloses a battery module of a traction battery of a motor vehicle with a cell stack composed of multiple battery cells, wherein the cell stack composed of the battery cells is subjected to a mechanical preload force via a clamping system. The clamping system has at least one piston-cylinder unit that generates a preload force acting on the cell stack. The preload force can be kept constant regardless of the operating state of the battery cells.

[0004] DE 10 2014 212 113 A1 discloses a battery module with a plurality of battery cells and a clamping unit. The clamping unit has at least one clamping means arranged between a battery module housing and at least one battery cell. The clamping means has a temperature-dependent geometry.

[0005] DE 10 2011 100 623 A1 discloses a motor vehicle battery with a cell stack consisting of several battery cells arranged in a housing. The cell stack is clamped relative to the housing by clamping devices. The clamping devices are wedges or elastic materials such as rubber elastomers. The clamping devices are designed to swell depending on temperature or humidity and maintain the cell stack under appropriate tension.

[0006] There is a need for a traction battery of a motor vehicle with an improved application of a tension force to the battery cells.

[0007] The object of the invention is to create a novel traction battery for a motor vehicle. This object is achieved by a traction battery according to claim 1. According to the invention, the respective clamping element comprises a first clamping body, a second clamping body, and a swelling material arranged between the first clamping body and the second clamping body. When the swelling material comes into contact with a swelling agent, it swells, causing a relative movement between the first clamping body and the first clamping body of the respective clamping element, and thus applying a clamping force to at least one battery cell.

[0008] The present invention proposes that the at least one clamping element comprises the first clamping body, the second clamping body, and the swelling material arranged between the clamping bodies. When the swelling material comes into contact with the swelling agent, the swelling material preferably swells irreversibly and causes a defined relative movement between the two clamping bodies of the respective clamping element. The clamping bodies enhance the swelling of the swelling material in a defined spatial direction, namely in the spatial direction in which the clamping force is to be applied to the at least one battery cell.

[0009] Preferably, a coolant flows directly around the battery cells, or the coolant flows through the traction battery for cooling, with the coolant serving as a swelling agent. This design of the traction battery is particularly preferred. For assembly, the battery cells can advantageously be installed inside the traction battery. During operation, the coolant flows through the traction battery, acting as a swelling agent. A defined clamping force or preload force is then applied to the respective battery cell.

[0010] Preferably, the first clamping body of the respective clamping element engages the battery housing or battery module housing, wherein the second clamping body of the respective clamping element is displaceable relative to the first clamping body in the direction of the at least one battery cell when the swelling material swells. Alternatively, the first clamping body of the respective clamping element engages at least one battery cell, wherein the second clamping body of the respective clamping element is displaceable relative to the first clamping body in the direction of the battery housing or battery module housing when the swelling material swells. In both ways, a defined clamping force can be applied to the at least one battery cell.

[0011] Preferably, at least the first clamping body of the respective clamping element has openings for the passage of the swelling agent. This is particularly preferred for bringing the swelling agent into contact with the swelling material.

[0012] Preferably, the first clamping body of the respective clamping element is cylindrical, and the second clamping body of the respective clamping element is piston-shaped. Alternatively, the first clamping body of the respective clamping element is funnel-shaped, and the second clamping body of the respective clamping element is conical. If the first clamping body of the respective clamping element is funnel-shaped and the second clamping body of the respective clamping element is conical, not only can the clamping force be advantageously applied to the at least one battery cell in a defined spatial direction, but a defined damping effect can also be provided.

[0013] Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. Herein: Fig. 1a a highly schematic representation of a traction battery in a first state, Fig. 1b the traction battery in a second state, Fig. 2a a detail of the Fig. 1a, Fig. 2b a detail of the Fig. 1b, Fig. 3a an alternative detail to the detail of the Fig. 2a, Fig. 3b an alternative detail to the detail of the Fig. 2b.

[0014] Fig. 1 shows a highly schematic view of a traction battery 10 of a motor vehicle, wherein battery cells 12 are arranged in a battery housing 11 and thus a stack 12a of battery cells 12 is arranged.

[0015] Housing walls 11a, 11b, 11c and 11d of the battery housing 11 are shown, which together define a receiving space 13 of the battery housing 11 for the battery cells 12. Thus, the housing walls 11a, 11b and the housing walls 11c, 11d are opposite each other. It should be noted that the Fig. The traction battery shown in Figure 1 can also be a battery module. Such a battery module then has a battery module housing in which the battery cells are arranged.

[0016] The battery cells 12 are arranged in the battery housing 11 such that the battery cells 12 are supported on the housing wall 11a, or the stack 12a is supported on the housing wall 11a, and is spaced apart from the housing walls 11c, 11d. In order to arrange the battery cells 12 or the stack 12a in a defined manner within the interior 13 of the battery housing 11 and to hold them in their position within the interior 13 of the battery housing 11, the battery cells 12 or the stack 12a are subjected to a defined clamping force via clamping elements 14.

[0017] Fig. 1a shows the clamping elements 14 in a state in which they do not exert any clamping force on the battery cells 12 or the stack 12a. In Fig. 1b, however, the clamping elements 14 exert a clamping force on the battery cells 12 or the stack 12a.

[0018] The clamping elements 14 have a first clamping body 14a, a second clamping body 14b, and a swelling material 14c arranged between the first clamping body 14a and the second clamping body 14b. When the swelling material 14c of the respective clamping element 14 comes into contact with a swelling agent 15, the swelling material 14c of the respective clamping element 14 swells irreversibly and causes a relative movement between the first clamping body 14a of the respective clamping element 14 and the second clamping body 14b thereof, thus applying a defined clamping force to the at least one battery cell 12 or the stack 12a.

[0019] In Fig. 1b, Fig. 2b and Fig. 3b shows the swelling agent 15, which, upon contact with the swelling material 14c, causes the swelling of the swelling material 14c of the respective clamping element 14. Preferably, the swelling agent 15 is a coolant, which serves to cool the traction battery 10, namely the battery cells 12, and which flows through the traction battery 10 during operation and directly or immediately around the battery cells 12 or the stack 12a of battery cells 12.

[0020] In the example of Fig. 1a, Fig. 1b, the first clamping body 14a of the respective clamping element 14 firmly engages the battery housing 11, namely the housing wall 11b, wherein the second clamping body 14b of the respective clamping element 14 is displaceable perpendicular to the housing wall 11b relative to the first clamping body 14a when the swelling material 14c of the respective clamping element 14 swells, in order to bring the second clamping body 14b into contact with the at least one battery cell 12 or the stack 12a and thus clamp the at least one battery cell 12 or the stack 12a in the battery housing 11. In Fig. 1a, Fig. 1b, the first clamping body 14a of the respective clamping element 14 is fixed to the housing, the second clamping body 14b is displaceable relative to the housing and can be brought into contact with the at least one battery cell 12 or the stack 12a in order to apply the defined clamping force to the at least one battery cell 12 or the stack 12a of battery cells 12.

[0021] As already explained, the second clamping body 14 of the respective clamping element 14 is preferably displaceable relative to the first clamping body 14a in a single defined spatial direction, namely in the spatial direction in which the clamping force is to be applied to the respective battery cell 12. In the other spatial directions, the clamping bodies 14a, 14b of the respective clamping element 14 prevent the swelling of the swelling material 14c. This increases the swelling of the swelling material 14c of the respective clamping element 14 in the desired spatial direction.

[0022] In contrast to the shown embodiment of the Fig. 1a, Fig. 1b, it is also possible for the first clamping body 14a of the respective clamping element 14 to engage a respective battery cell 12 or the stack 12a of battery cells 12 and then, when the swelling material 14c of the respective clamping element 14 swells, the second clamping body 14b of the respective clamping element 14 is displaceable relative to the first clamping body 14a of the respective clamping element 14 in order to bring the same into contact with the housing wall 11b.

[0023] In Fig. 1a, Fig. 1b, Fig. 2a, Fig. 2b, the first clamping body 14a of the respective clamping element 14 is cylindrical and the second clamping body 14b of the respective clamping element 14 is piston-like.

[0024] When the swelling material 14c of the respective clamping element 14 swells, the second, piston-like clamping body 14b of the respective clamping element 14 is moved out of the first, cylindrical clamping body 14a. To facilitate the contact of the swelling agent 15 with the swelling material 14c of the respective clamping element 14, openings 16 for the passage of the swelling agent 15 are provided at least in the first clamping body 14a. Fig. 2a, the second clamping body 14b also has such openings 16.

[0025] As already explained, coolant is preferably used as the swelling agent 15. The swelling material 14c can be an EPDM material or a silicone material.

[0026] Fig. 3a, Fig. 3b show an alternative embodiment of a clamping element 14, namely Fig. 3a in a non-swollen state of the source material 14c and Fig. 3b in a swollen state of the source material 14c. In Fig. 3a, Fig. 3b, the first clamping body 14a of the respective clamping element 14 is funnel-shaped and the second clamping body 14b of the respective clamping element 14 is conical or truncated conical. The first clamping body 14a, in turn, has the openings 16 for the passage of the swelling agent 15 and thus for bringing the swelling agent 15 into contact with the swelling material 14c of the respective clamping element 14. The clamping element 14 of the Fig. 3a, Fig. 3b causes, upon swelling of the swelling material 14c, a defined displacement of the second clamping body 14b relative to the first clamping body 14a in a defined spatial direction and thus the application of a clamping force to the respective battery cell 12 in this defined spatial direction, additionally the provision of a damping force perpendicular to the clamping force.

[0027] Accordingly, a traction battery 10 is proposed that has a plurality of battery cells 12. The battery cells 12 are clamped in the battery housing 11 or in battery module housings of battery modules by means of clamping elements 14, wherein each clamping element 14 has two clamping bodies 14a, 14b that can be displaced relative to one another, the relative movement of which is provided by the swelling of a swelling material 14c of the respective clamping element 14 when it is brought into contact with a swelling agent 15. The swelling agent 15 is a cooling medium, which serves to cool the battery cells 12 and, for this purpose, flows through the traction battery 10.

[0028] In particular, the first clamping body 14a of the respective clamping element 14 ensures that the swelling material 14c of the respective clamping element 14 swells in a single defined spatial direction and thus displaces the second clamping body 14b of the respective clamping element 14 in this defined spatial direction in order to apply the clamping force to the respective battery cell 12 in this spatial direction. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 212 887 A1

[0003] DE 10 2014 212 113 A1

[0004] DE 10 2011 100 623 A1

[0005]

Claims

A traction battery (10) of a motor vehicle, comprising a plurality of battery cells (12), wherein the battery cells (12) are arranged either in a battery housing (11) of the traction battery (10) or in battery module housings of battery modules of the traction battery (10) positioned in the battery housing (11), wherein the battery cells (12) in the battery housing (11) or in the respective battery module housing are subjected to a clamping force via at least one clamping element (14), characterized in that the respective clamping element (14) each has a first clamping body (14a), a second clamping body (14b), and a swelling material (14c) arranged between the first clamping body (14a) and the second clamping body (14b), the swelling material (14c) of the respective clamping element (14) swells when the swelling material (14c) comes into contact with a swelling agent (15),causes a relative movement between the first clamping body (14a) and the second clamping body (14b) of the respective clamping element (14) and thus applies a clamping force to at least one battery cell (12). Traction battery according to claim 1, characterized in that the battery cells (12) are surrounded by a coolant for cooling, and the coolant serves as a swelling agent (15). Traction battery according to claim 1 or 2, characterized in that the first clamping body (14a) of the respective clamping element (14) engages the battery housing (11) or battery module housing, the second clamping body (14b) of the respective clamping element (14) is displaceable relative to the first clamping body (14a) in the direction of the at least one battery cell (12) when the swelling material (14c) swells. Traction battery according to claim 1 or 2, characterized in that the first clamping body (14a) of the respective clamping element (14) engages at least one battery cell (12), the second clamping body (14b) of the respective clamping element (14) is displaceable relative to the first clamping body (14a) in the direction of the battery housing (11) or battery module housing when the swelling material (14c) swells. Traction battery according to one of claims 1 to 4, characterized in that the first clamping body (14a) of the respective clamping element (14) is cylindrical and the second clamping body (14b) of the respective clamping element (14) is piston-shaped. Traction battery according to one of claims 1 to 4, characterized in that the first clamping body (14a) of the respective clamping element (14) is funnel-shaped and the second clamping body (14b) of the respective clamping element (14) is conical. Traction battery according to one of claims 1 to 6, characterized in that at least the first clamping body (14a) of the respective clamping element (14) has openings (16) for the passage of the swelling agent (15). Traction battery according to one of claims 1 to 7, characterized in that the swelling material (14c) of the respective clamping element (14) is an EPDM material. Traction battery according to one of claims 1 to 7, characterized in that the swelling material (14c) of the respective clamping element (14) is a silicone material.

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