Traction battery module

Abstract

The invention relates to a traction battery module (10), comprising: a housing body (20) with a rectangular cross section, the housing body having four side walls (21, 22, 23, 24) and two end walls (25, 26); and a plurality of unit elements (301-306) arranged in the housing body (20) and combined into a unit element stack (30). A retaining frame (40, 40') is respectively arranged at the longitudinal ends of the two end sides of the unit element stack (30), and the longitudinal ends of the unit elements (301-306) are respectively retained on the retaining frame in such a way that the unit element stack (30) is spaced apart from the four side walls (21, 22, 23, 24), and each retaining frame (40, 40') has a spring assembly (50) on its spring side (11) facing the side wall (23), but has no spring assembly on its fixed side (12) opposite to the spring side (11), so that the retaining frame (40, 40') is pressed against the side wall (24) assigned to the fixed side (12) by the spring assembly (50).

Description

Technical Field

[0001] The invention relates to a traction battery module of an electric vehicle, the traction battery module comprising: a housing body with a substantially rectangular cross section, the housing body having four side walls and two end walls; and a plurality of plate-shaped battery cell elements arranged in the housing body, the battery cell elements being combined into a cell element stack. Background Art

[0002] To produce high-voltage (HV) traction battery modules for electric vehicles, for example, a metal extruded profile is used for the housing body, which forms the four side walls and into which the cell stack is pushed from the open end during assembly. In order to achieve a good thermal connection between the cell stack and the housing side walls, which are cooled in the installed state, a heat-conducting mass such as the following is filled in: That is, the heat conductive substance thermally connects, for example, the bottom side of the unit element stack to the adjacent side wall.

[0003] Extruded profiles have relatively large manufacturing tolerances, so the unit element stack must be smaller than the smallest possible inner dimension of the extruded profile by at least this manufacturing tolerance. These circumstances make it necessary to fix the unit element stack in the housing in a tolerance-compensating manner relative to one or more spatial axes, for example by means of elastic spring elements.

[0004] Such traction battery modules are known, for example, from DE 10 2014 108 803 A1, DE 10 2018 2016 32 A1 or DE 10 2018 126 572 A1. However, assembly is in some cases complex and leads to an unclear spatial positioning of the cell stack in the housing during assembly. When the distance between the cooled housing side wall and the cell stack is relatively large in the state installed in the vehicle, this leads to a relatively high demand for heat-conducting mass in order to ensure a sufficient thermal connection of the cell stack to the cooled side wall in terms of process safety. Summary of the invention

[0005] Against this background, it is an object of the present invention to provide a traction battery module which can be produced cost-effectively.

[0006] According to the invention, this object is achieved by a traction battery module having the features described below.

[0007] The traction battery module according to the invention has a housing body with a substantially rectangular cross section, four side walls and two end walls. The four side walls can be formed, for example, by a monolithic profile body, for example a metal profile body produced by an extrusion process, which is closed during the production of the traction battery module by placing the two end walls to form a sealed closed housing. A plurality of plate-shaped battery cell elements are arranged in the housing body, which are arranged parallel to one another and to the two side walls and are electrically and mechanically combined to form a cell element stack. Separate holding frames are provided at the longitudinal ends of the two end sides of the cell element stack, to which the longitudinal ends of the cell elements are respectively mechanically held in such a way that the cell elements are mechanically combined and the cell element stack is at least minimally spaced apart from the corresponding side walls of the housing in all four transverse directions.

[0008] Each holding frame has an elastic spring assembly on its spring side facing the side wall, and no spring assembly on its fixed side opposite to the spring side, so that the holding frame is pressed against the inner side of the housing side wall assigned to the fixed side by the spring assembly. Generally speaking, the side wall forming the fixed side is the side wall of the lower part of the housing body, while the spring side is the side wall of the upper part of the housing body. Therefore, the holding frame mechanically holds all the unit elements of the unit element stack together and ensures at least a minimum spatial distance between the unit element stack and all the side walls and end walls of the housing body. However, on the spring side, the unit element stack is not spaced apart from the corresponding side wall by a rigid spacing element, but by an elastic spring assembly, so that tolerance compensation is carried out on the spring side of the unit element stack in this way. On the fixed side, it is always ensured that the distance between the unit element stack and the assigned side wall is the same.

[0009] In this way, a relatively small distance between the cell stack and the associated side wall can be set on the fastening side in a reliable and process-safe manner. Due to the relatively small distance between the cell stack and the associated side wall (cooled in the state installed in the vehicle), a good heat transfer can be ensured regardless of the type of thermal connection between the cell stack and the assigned cooled side wall.

[0010] The gap between the cell stack and the side wall on the fixed side is preferably filled with a heat-conducting agent. Since the defined distance between the cell stack and the side wall on the fixed side is always the same small, a relatively small amount of heat-conducting material is sufficient to establish a reliable, comprehensive thermal connection between the cell stack and the relevant side wall in terms of process safety.

[0011] Preferably, the fixed sides of the two holding frames are at the bottom, so that the lower side wall belongs to the fixed side, and the spring sides are at the top, so that the upper side wall belongs to the spring side. In the state installed in the vehicle, the lower side wall of the housing body is cooled, for example, by a liquid cooling device.

[0012] In particular during the production and assembly of the traction battery module and in the state installed in the vehicle, the plate-shaped unit elements are preferably each located in a vertical plane.

[0013] It is particularly preferred that the two spring assemblies of the two end-side holding frames each have an insertion bevel effective in a single longitudinal direction, i.e. the assembly direction, wherein the two insertion bevels have the same longitudinal orientation. When assembling the traction battery module, the cell stack with the two holding frames already mounted thereon is pushed in the longitudinal direction into the profile body which is still open at one or both end sides. During the insertion, the two spring assemblies of the two holding frames are gradually compressed in the transverse direction at the edge of the opening until the relevant spring assembly is respectively completely pushed in. This greatly simplifies the assembly of the cell stack with the holding frames fastened thereto in the housing.

[0014] The spring assembly is preferably formed by a plurality of individual spring elements distributed over the width of the spring side. This ensures a uniform lateral force of the spring elements distributed over the entire width of the spring side on the retaining frame.

[0015] According to a preferred embodiment, the two holding frames are made of plastic and can therefore be manufactured relatively cheaply. The spring assembly or spring elements can in principle consist of a different material from the holding frame itself, but are preferably designed integrally with the plastic holding frame. This reduces the manufacturing costs of the traction battery module.

[0016] Preferably, the unit elements have electrical contact elements at their longitudinal ends held together by the two holding frames. The contact elements of the unit elements adjacent to each other are electrically connected to each other via busbars. These busbars are particularly preferably held directly by the holding frames, i.e., they do not have to be fixed to the holding frames or the housing body via separate fixing elements.

[0017] In general, the present invention discloses the following technical solution 1, and the following 2-11 are preferred technical solutions of the present invention:

[0018] 1. A traction battery module (10), comprising: a housing body (20) having a substantially rectangular cross section, the housing body having four side walls (21, 22, 23, 24) and two end walls (25, 26); and a plurality of plate-shaped battery cell elements (301-306) arranged in the housing body (20), the battery cell elements being arranged parallel to each other and to two of the four side walls (21, 22) and being combined into a cell element stack (30),

[0019] A holding frame (40, 40') is provided at the longitudinal ends (13, 14) of the two end sides of the unit element stack (30), and the longitudinal ends (13, 14) of the unit elements (301-306) are respectively held on the holding frame in such a way that the unit element stack (30) is spaced apart from the four side walls (21, 22, 23, 24) in all four transverse directions, and

[0020] Each holding frame (40, 40') has a spring assembly (50) on its spring side (11) facing the side wall (23), but no spring assembly on its fixed side (12) opposite to the spring side (11), so that the holding frame (40, 40') is pressed against the side wall (24) assigned to the fixed side (12) by the spring assembly (50).

[0021] 2. The traction battery module (10) according to item 1 above, wherein a gap between the unit element stack (30) and the side wall (24) on the fixed side is filled with a thermal conductive agent (60).

[0022] 3. The traction battery module (10) according to any one of the above 1-2, wherein the four side walls (21-24) are formed by an integral profile body (21').

[0023] 4. The traction battery module (10) according to any one of the above 1-3, wherein the fixed side (12) is located at the bottom and the spring side (11) is located at the top.

[0024] 5. The traction battery module (10) according to any one of the above 1-4, wherein the unit elements (301-306) are each located in a vertical plane.

[0025] 6. The traction battery module (10) according to any one of the above 1 to 5, wherein the two spring assemblies (50) of the two retaining frames (40, 40') each have an insertion bevel (54) effective in the longitudinal direction, wherein the two insertion bevels (54) have the same orientation in the longitudinal direction.

[0026] 7. The traction battery module (10) according to any one of the above 1 to 6, wherein the spring assembly (50) is formed by a plurality of spring elements (52) distributed over the width of the spring side.

[0027] 8. The traction battery module (10) according to any one of the above 1 to 7, wherein the two holding frames (40, 40') are each made of plastic.

[0028] 9. The traction battery module (10) according to any one of the above 7 and 8, wherein the spring elements (52) are designed integrally with the holding frame (40, 40').

[0029] 10. The traction battery module (10) according to any one of the above 1 to 9, wherein the unit elements (301-306) have electrical contact elements (34) at their longitudinal ends, wherein the contact elements (34) of mutually adjacent unit elements (301-306) are electrically connected to each other via bus bars (36).

[0030] 11. The traction battery module (10) according to item 10 above, wherein the busbar (36) is directly held by the holding frame (40, 40'). BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following is a detailed explanation of the embodiments of the present invention with reference to the accompanying drawings. In the accompanying drawings:

[0032] Figure 1 shows a preassembled unit element stack before it is pushed into the profile body, comprising a retaining frame arranged at the longitudinal ends and a housing profile body forming four side walls,

[0033] Figure 2 shows a longitudinal section through an assembled traction battery module, in which the cell stack has been pushed into the housing body, a heat conducting agent has been filled in the region of the lower housing side wall, and two end walls have been installed, and

[0034] Figure 3 The front view shows the end wall with the end wall open. Figure 2 Traction battery module. DETAILED DESCRIPTION

[0035] exist Figure 2 and Figure 3Schematically shows an assembled traction battery module 10 for an electric vehicle, which has a square metal housing body 20 and a unit element stack 30 supported in the metal housing body in an airtight manner. The housing body 20 is composed of two vertical side walls 21, 22, two horizontal side walls 23, 24 and two vertical end walls 25, 26 perpendicular to the side walls 21-24. The side walls 21-24 are composed of Figure 1 The illustrated embodiment is formed of a one-piece profile body 21 ′ which is produced by an extrusion process.

[0036] The unit cell stack 30 is composed of a plurality of plate-shaped electrochemical unit cells 301 - 306 , which are arranged parallel to each other and in a vertical plane.

[0037] Plastic holding frames 40, 40' are respectively provided at the two longitudinal ends of the cell element stack 30, which surround the longitudinal ends 13, 14 of the cell elements 301-306 in a form-fitting manner and combine them into a square battery cell stack 30. Figure 2 and Figure 3 As can be seen in FIG. 1 , the unit elements 301-306 are held and packaged by two holding frames 40, 40' in such a way that the unit element stack 30 is Figure 3 In all four lateral directions shown, the spring assemblies 50 are spaced apart from the corresponding associated side walls 21-24. Each holding frame 40, 40' has a spring assembly 50 on its spring side 11 facing the upper side wall 23. No spring assembly is provided on the other three lateral sides facing the side walls 21, 22, 24. The two spring assemblies 50, 50' are respectively composed of Figure 2 The spring assembly 50 or the spring elements 52 are formed in one piece with the plastic holding frame 40, 40'.

[0038] The insertion inclined portions 54 of the spring elements 52 of the spring assemblies 50, 50' of the two retaining frames 40, 40' have the same longitudinal orientation, so that when the unit element stack 30 is pushed into the profile body 21', the spring elements 52 are compressed proximally in the vertical direction, so that the unit element stack 30 is vertically tensioned with its two longitudinal ends inside the four side walls 21-24.

[0039] The unit elements 301-306 have electrical contact elements 34 in the form of contact strips at their longitudinal ends, which are electrically connected to one another via conductive metal busbars 36, so that the unit elements 301-306 are electrically connected to one another in series. The busbars 36 are held in place by plastic retaining tongues 80, 81, which are designed integrally with the plastic body of the respective retaining frame 40, 40'.

Claims

1. A traction battery module (10), comprising: a housing body (20) having a substantially rectangular cross section, the housing body having four side walls (21, 22, 23, 24) and two end walls (25, 26); and a plurality of plate-shaped battery cell elements (301-306) arranged in the housing body (20), the battery cell elements being arranged parallel to each other and to two of the four side walls (21, 22) and being combined into a cell element stack (30), A holding frame (40, 40') is respectively arranged at the longitudinal ends (13, 14) of the two end sides of the unit element stack (30), and the holding frame (40, 40') surrounds the longitudinal ends (13, 14) of the end sides of the unit elements (301-306) in a form-fitting manner, so that the unit element stack (30) is spaced apart from the four side walls (21, 22, 23, 24) in all four transverse directions, and Each holding frame (40, 40') has a spring assembly (50) on its spring side (11) facing the side wall (23), and no spring assembly on its fixing side (12) opposite the spring side (11), so that the holding frame (40, 40') is pressed against the side wall (24) assigned to the fixing side (12) by the spring assembly (50), wherein the fixing side (12) is located at the bottom and the spring side (11) is located at the top, wherein the spring assembly (50) is designed integrally with the holding frame (40, 40').

2. The traction battery module (10) according to claim 1, wherein a gap between the unit element stack (30) and the side wall (24) of the fixed side is filled with a thermal conductive agent (60).

3. The traction battery module (10) according to claim 1 or 2, wherein the four side walls (21-24) are formed by a one-piece profile body (21').

4. The traction battery module (10) according to claim 1 or 2, wherein the cell elements (301-306) are each located in a vertical plane.

5. The traction battery module (10) according to claim 1 or 2, wherein the two spring assemblies (50) of the two holding frames (40, 40') each have an insertion bevel (54) effective in the longitudinal direction, wherein the two insertion bevels (54) have the same orientation in the longitudinal direction.

6. The traction battery module (10) according to claim 1 or 2, wherein the spring assembly (50) is formed by a plurality of spring elements (52) distributed over the width of the spring side.

7. The traction battery module (10) according to claim 1 or 2, wherein the two holding frames (40, 40') are each made of plastic.

8. The traction battery module (10) according to claim 1 or 2, wherein the cell elements (301-306) have electrical contact elements (34) at their longitudinal ends, wherein the contact elements (34) of mutually adjacent cell elements (301-306) are respectively electrically connected to one another via busbars (36).

9. The traction battery module (10) according to claim 8, wherein the busbars (36) are held directly by the holding frame (40, 40').

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