Automotive traction battery

Abstract

The invention relates to a motor vehicle traction battery (10) with an inherently rigid battery housing (20) in which a cell stack with several battery cells (30) stacked parallel to one another is arranged between two mutually parallel battery housing walls (21, 22), wherein an elastic intermediate structure (40) is arranged between the battery cells (30) of the cell stack, which spaced the battery cells (30) apart from each other over their entire surface, wherein the intermediate structure (40) is formed by a plurality of prefabricated elastic intermediate structure strips (401, 402, 403, 404) which are oriented parallel to each other in a longitudinal direction (z), wherein at least one intermediate structure strip (402, 403, 404) of the intermediate structure (40) has a non-rectangular cross-sectional shape when viewed in a transverse plane (xy).

Description

[0001] The invention relates to a motor vehicle traction battery with an inherently rigid battery housing in which the battery cells of a cell stack are spaced from one another by elastic intermediate structures and clamped between two battery housing walls.

[0002] EP 3 133 669 A1, US 2022 255 182 A1, CA 2 990 009 A1, and JP 2023 505 971A each disclose a battery with stacked battery cells, each held spaced apart by elastic prefabricated intermediate structures. The spring characteristic of the intermediate structure is usually adjusted by selecting a material with the desired elasticity or the desired material-specific spring characteristic. This is cumbersome and complex in practice.

[0003] From EP 3 993 139 A1, US 2013 / 0 078 491 A1, DE 11 2011 105 605 T5 and WO2020 / 017 458 A1, one-piece elastic intermediate structures are known which have elastic intermediate structure strips on a base plate.

[0004] The object of the invention is to expand the possibilities for adjusting the elasticity of the intermediate structures between the battery cells of a cell stack of a motor vehicle traction battery in a simple manner.

[0005] This object is achieved according to the invention with a motor vehicle traction battery having the features of claim 1

[0006] The automotive traction battery according to the invention has an inherently rigid and largely fluid-tight battery housing in which at least one cell stack with several battery cells stacked parallel to one another is arranged between two parallel battery housing walls. The battery cells can be essentially prismatic in shape, particularly when new.

[0007] The battery housing walls in question can generally be formed by outer walls and / or inner walls of the battery housing. The two battery housing walls are preferably located in a vertical plane.

[0008] An intermediate structure is arranged between each battery cell, completely spacing the two adjacent battery cells from each other. The intermediate structure is inherently elastic in order to be able to compensate for both temporary and permanent changes in battery cell volume, and in particular changes in size in the normal direction to the plate-like intermediate structure and the plate-like battery cells, and to hold the battery cells of a cell stack together in a fixed position. Each battery cell is adjacent to at least one intermediate structure, but can also be directly adjacent on both sides by an intermediate structure.

[0009] The intermediate structure is essentially formed by several prefabricated, inherently elastic intermediate structure strips oriented parallel to one another in a longitudinal direction. The longitudinal direction is not a specific spatial direction in this case, but is parallel to the base plane of the plate-like battery cells or the intermediate structure itself. The intermediate structure strips are prefabricated, meaning that in the case of intermediate structure strips made of plastic, they are already cured and are not first applied as a flowable plastic material to a battery housing wall to cure there. The largest part of the total area of ​​an intermediate structure is formed by the prefabricated intermediate structure strips, but not necessarily the entire area of ​​the intermediate structure.Particularly preferably, at least 70% of the total area of ​​the intermediate structure is formed by parallel, prefabricated, and inherently elastic intermediate structure strips. The intermediate structure strips do not necessarily have to be laid completely linearly over their entire length.

[0010] Between the intermediate structure strips, longitudinal cavities are formed which are filled with a liquid.

[0011] At least one intermediate structure strip of the intermediate structure has a non-rectangular cross-sectional shape, viewed in a transverse plane section, but a cross-sectional shape that deviates significantly from the rectangular cross-sectional shape. The cross-sectional shape within the meaning of the present invention is the shape assumed by the intermediate structure strip in its mechanically relaxed state before the cell stack is installed in the battery housing. A non-rectangular cross-sectional shape is defined here such that the cross-sectional shape of the intermediate structure strip deviates in area by at least 10% from a rectangle enclosing the relevant cross-section, particularly preferably by at least 20%.

[0012] The intermediate structure strips of the intermediate structure have at least two different cross-sectional shapes. Thus, particularly preferably, intermediate structure strips close to the edge can have a different cross-sectional shape than intermediate structure strips further away from the edge and more centrally located, since different and preferably greater spring forces are required in the edge region than in the central region of the intermediate structure.

[0013] The cross-sectional shape of the intermediate structure strip can be selected and dimensioned so that the spring characteristic of the respective intermediate structure strip can be precisely adjusted locally to the desired mechanical behavior. In this way, different spring characteristics can be realized locally across the entire surface of the intermediate structure without having to select different materials for the prefabricated elastic intermediate structure strips.

[0014] In particular, a relatively inelastic material can be chosen as the only material for all intermediate structure strips, so that the total volume of all intermediate structure strips of the intermediate structure is relatively small and the total volume of all cavities of the intermediate structure is relatively large.

[0015] Cooling channels for a flowing cooling fluid, namely a cooling liquid, for example a cooling oil, are formed between the intermediate structure strips.

[0016] The inter-structure cavities serve to actively cool the adjacent battery cells by a cooling fluid flowing through the cavities, so that the thermal properties are improved by using a relatively hard and elastic material for the consequently relatively small-volume inter-structure strips.

[0017] All intermediate structure strips of the intermediate structure are made of the same material and consist of an elastomer body made of a silicone solid elastomer or a polyurethane elastomer.

[0018] Preferably, at least one non-rectangular intermediate structure strip has a substantially convex-convex, concave-concave, or concave-convex cross-sectional shape. The type of cross-sectional shape can, in particular, define the change or non-change in the spring constant depending on the spring travel.

[0019] An embodiment of the invention is explained in more detail below with reference to the drawings. They show: Fig. 1 a schematic sectional view of a motor vehicle traction battery according to the invention with several stacked battery cells which are spaced from each other by an elastic intermediate structure formed by mutually parallel intermediate structure strips, Fig. 2 shows four different intermediate structure strips with different cross-sectional shapes, and Fig. 3 the spring characteristics of the four different intermediate structure strips of the Fig. 2.

[0020] In the Fig. Figure 1 schematically shows a section through a horizontal xy plane of a vehicle traction battery 10. The vehicle traction battery 10 is a high-voltage traction battery with a system voltage of, for example, 400 V or 800 V.

[0021] The motor vehicle traction battery 10 has an inherently rigid prismatic or cuboid-shaped battery housing 20 with two battery housing walls 21, 22 that are parallel to one another and each extend in a vertical plane yz. Between the battery housing walls 21, 22, a cell stack with a plurality of parallel, stacked prismatic battery cells 30 is arranged. In their new state, the battery cells 30 are essentially prismatic and plate-like.

[0022] An elastic intermediate structure 40 is arranged between each two adjacent battery cells 30, which completely fills the gap-like space between two adjacent battery cells 30 and completely separates the two adjacent battery cells 30 from each other. Each battery cell 30 has a large-area first vertical side wall 36 and a second side wall 37 parallel thereto. On its two relatively small-area vertical end faces 34, 35, each battery cell 30 has an electrical connection body 38, via which the respective battery cell 30 is electrically connected to other battery cells 30 (not shown).

[0023] The intermediate structure 40 is formed in this case by a plurality of essentially parallel and elastic intermediate structure strips 401, 403, which are arranged parallel to one another and, in this case, oriented in a single longitudinal direction z. The intermediate structure strips 401, 403 each consist of an elastomer body 40', for example, a solid silicone elastomer or a polyurethane elastomer. The intermediate structure strips 401, 403 are prefabricated products that are bonded, for example, in a cured state, to the respective side wall 36, 37 during assembly of the traction battery.

[0024] Between the intermediate structure strips 401, 403, a cooling channel 60 is formed for a flowing cooling fluid 62, which in this case is a cooling liquid, for example, a cooling oil. In this way, the battery cells 30 can be directly liquid-cooled or heated.

[0025] As in the Fig. 1, the edge-side intermediate structure strips 401 have a rectangular cross-sectional shape, whereas the non-edge-side intermediate structure strips 403 have a concave-concave cross-sectional shape in the present embodiment.

[0026] In the Fig. 2 shows two further examples of suitable non-rectangular cross-sectional shapes for the intermediate structure strips, namely an intermediate structure strip 402 with a convex-convex cross-sectional shape and an intermediate structure strip 404 with a concave-convex cross-sectional shape. Fig. 3 are among the four different in the Fig. The corresponding spring characteristics are qualitatively shown for the cross-sectional shapes of the intermediate structure strips 401, 402, 403, 404 shown in Figure 2.

Claims

[1] Motor vehicle traction battery (10) with an inherently rigid battery housing (20) in which a cell stack with several battery cells (30) stacked parallel to one another is arranged between two mutually parallel battery housing walls (21, 22), wherein an elastic intermediate structure (40) is arranged between the battery cells (30) of the cell stack, which spaced the battery cells (30) apart from each other over their entire surface, wherein the intermediate structure (40) is formed by a plurality of prefabricated elastic intermediate structure strips (401, 403) which are oriented parallel to one another in a longitudinal direction (z), and wherein at least one intermediate structure strip (402, 403, 404) of the intermediate structure (40) has a non-rectangular cross-sectional shape when viewed in a transverse plane (xy), wherein the intermediate structure strips (401,403) are individually prefabricated and cured products which are glued to a respective side wall (36,37) of the battery cell (30), wherein the intermediate structure strips (401, 402, 403, 404) of the intermediate structure (40) have at least two different cross-sectional shapes. wherein the edge-side intermediate structure strips (401) have a different cross-sectional shape than the non-edge-side intermediate structure strips (403), wherein cooling channels (60) for a flowing liquid cooling fluid (62) are formed between the intermediate structure strips (401, 402, 403, 404), and wherein the intermediate structure strips (401, 402, 403, 404) are formed by an elastomer body (40'). [2] Automotive traction battery (10) according to claim 1, wherein the at least one non-rectangular intermediate structure strip (402, 403, 404) has a substantially convex-convex, concave-concave or concave-convex cross-sectional shape. [3] Automotive traction battery (10) according to claim 1 or 2, wherein the elastomer body (40') consists of a silicone solid elastomer or a polyurethane elastomer.

Images