Traction battery with plug-in battery modules

Abstract

Traction battery (100) for an electric car or hybrid electric vehicle, comprising a housing and several battery modules (20) arranged in the housing and attached to the housing base (10), wherein the battery modules (20) are attached by means of plug connections, by means of undercut pins (32) arranged on the housing base (10) and locking clips (40) arranged on the undersides of the battery modules (20), which engage the pins (32) in a form-fit and force-fit manner, characterized in that each battery module (20) is attached to the housing base (10) by means of three such plug connections and each plug connection has a translational degree of freedom lying in the mounting plane, wherein for each battery module (20) the degrees of freedom at its plug connections have different directions, such that the battery modules (20) can expand but cannot move.

Description

[0001] According to the preamble of claim 1, the invention relates to a traction battery, comprising a housing and several battery modules arranged in the housing and attached to the bottom of the housing.

[0002] A traction battery within the meaning of the invention is an electrical energy storage device for powering an electric car or hybrid electric vehicle. Such a battery can also be referred to as a traction battery. Various designs are known from the prior art. One common design involves screwing the individual battery or cell modules to the housing, particularly the housing base, at their corners using four screws, as shown in DE 10 2015 217 810 A1 (see there). Fig. 3).

[0003] The closest patent application, DE 10 2015 110 243 A1, describes a battery cell housing with a housing shell. A holding device is arranged on the bottom of the housing shell. A counter-holding device on a support is associated with the holding device. The holding device and the counter-holding device are designed to be positively engaged by an axial relative movement. The holding device and the associated counter-holding device can thus establish a snap-fit ​​connection through an axial relative movement.

[0004] Regarding the state of the art, reference is also made to DE 10 2011 103 990 A1, which describes a battery with a plurality of individual battery cells which are combined to form at least one cell block, and with a battery housing for receiving the at least one cell block, wherein the at least one cell block is statically determinately mounted in the battery housing.

[0005] The invention is based on the objective of providing an improved traction battery of the type mentioned above, which does not have, or at least only has to a lesser extent, at least one disadvantage associated with the nearest prior art.

[0006] This problem is solved by the traction battery according to the invention with the features of claim 1. Further developments and embodiments result from the dependent claims, the following description of the invention and the drawing.

[0007] In the traction battery according to the invention, the battery modules are fastened by means of plug connections, in particular only by means of plug connections, by means of undercut pins arranged on the bottom of the housing and locking or retaining clips arranged on the undersides of the battery modules, which engage the pins in a form-fit and force-fit manner.

[0008] The battery modules can be easily attached to the pins by simply pushing them on, requiring no tools. This significantly simplifies the assembly process and, if necessary, also facilitates the removal of the battery modules. The invention is therefore particularly suitable for series and mass production. Furthermore, the elimination of screw flanges or holes provides more installation space. In addition, the reduction in conventional fasteners leads to cost and weight savings.

[0009] According to the invention, each battery module is attached to the housing base by three plug connections. Each battery module is thus supported at only three mounting or connection points, thereby preventing static overdetermination and enabling statically determinate support, which in particular prevents wobbling or tilting.

[0010] According to the invention, each connector has a translational degree of freedom lying in the mounting plane in order to compensate for thermal expansion of the battery modules and / or so-called module swelling. Furthermore, this allows for the compensation of manufacturing and assembly tolerances. According to the invention, the degrees of freedom at the connectors (i.e., at the mounting or connection points) of each battery module are provided to have different directions, such that the battery modules can expand but cannot shift.

[0011] The battery modules can have groove-like pockets on their undersides in which the locking clips are arranged. These groove-like pockets are formed, in particular, directly on or in the underside of the module housing (bottom of the casing). This saves installation space and avoids interfering contours, thus enabling the battery modules to rest flush against the base of the battery housing. The pockets can also protect the locking clips. Furthermore, the inner surfaces of the pockets can apply counterforces to the locking clips. The locking clips are suitablely secured in the pockets, in particular in such a way that they are replaceable. Preferably, the locking clips are expanded when attached or connected to the pins on the underside and are thereby held in place in the groove-like pockets.

[0012] The locking clips are preferably omega-shaped in cross-section and have two locking arms (or a pair of locking arms) that point inwards (into the omega shape).

[0013] The locking clips are preferably manufactured in one piece from sheet metal, preferably from spring steel sheet. The locking clips can be stamped and bent parts produced, for example, by stamping and bending sheet metal, particularly spring steel sheet. Preferably, all locking clips are identical.

[0014] Preferably, metallic (first) connecting elements are provided, which are suitably attached to the housing base and each have an undercut pin projecting from the housing base, as explained in more detail below. The snap-in clips are complementary second connecting elements.

[0015] The traction battery according to the invention can further comprise at least one control unit or control device or the like, which is attached to the housing in an analogous manner, i.e. by means of undercut pins arranged on the housing, in particular on the housing base, and locking clips arranged on the outer surface, in particular on the underside, of the control unit, which engage or can engage the pins in a form-fit and force-fit manner.

[0016] The traction battery according to the invention is in particular a high-voltage battery (HV battery).

[0017] The invention is explained in more detail below with reference to the drawing. Fig. Figure 1 shows the attachment of a battery module to the bottom of a battery housing. Fig. Figure 2 shows in two views the connecting elements of a plug connection for attaching the battery module. Fig. 1. Fig. Figure 3 shows the underside of the attached battery module. Fig. 1.

[0018] Fig. Figure 1 shows two battery modules 20 in a traction battery 100, one of which is already attached to the base 10 of a housing (not shown below) and the other is being attached by vertical insertion (in the z-direction). The battery modules 20 are attached by means of plug connections, for which connecting elements 30 with undercut pins 32 are provided on the base 10 of the housing, and locking clips 40 are arranged in groove-like pockets 21 on the undersides of the battery modules 20, which engage the pins 32 in a form-fitting and force-fit manner. Preferably, all battery modules 20 of the traction battery 100 are attached in this way.

[0019] Each of the battery modules 20 is attached to the housing base 10 by three plug connections, wherein the battery modules 20 are attached at one of their narrow lower edges by two plug connections arranged in the corners and at the opposite lower edge by a plug connection arranged centrally. Each plug connection is designed to allow one translational degree of freedom of movement lying in the mounting plane, as shown in Fig. 2b and Fig. Figure 3 is illustrated by the double arrows, where the degrees of freedom of movement allowed at the opposite lower edges or narrow sides are perpendicular to each other (two locking clips 40 are aligned or at least parallel in the x-direction, and the third locking clip 40 is aligned perpendicular to them in the y-direction). This allows for thermal expansion and age-related swelling of the battery modules 20 while ensuring optimal hold (displacement is impossible due to mutual locking).

[0020] Fig. Figure 2 shows the connecting elements 30 and 40, which form a plug connection. The first connecting element 30 is essentially rotationally symmetrical and has a joining section 31, which can be threaded (e.g., an M4 or M6 thread) for screwing into the housing base 10. Alternatively, the connecting element 30 can be riveted, crimped, welded, or bonded to the housing base 10 and is designed accordingly. The fastening can be made directly to the housing base 10 or indirectly, e.g., to rails, supports, or the like. The connecting element 30 also has an undercut pin 32, which is designed like a ball stud or at least approximately like a ball stud.Between the joining section 31 and the pin 32 is a section 33, which serves to apply screw-in forces, forms a screw-in stop, and has a plate-like support surface 34 for the second connecting element, designed as a spring element 40. The sections 33 can optionally be countersunk in the housing base 10. The connecting element 30 shown is manufactured in one piece from metal. The connecting element 30 can also be designed as non-rotationally symmetrical.

[0021] The spring element 40 (second connecting element) is formed from a formed spring steel sheet and has an approximately omega shape in cross-section (see Fig. 2a), so that the undercut pin 32 of the first connecting element 30 can be engaged. The omega shape allows for extension in the z-direction. The spring element 40 has two paired locking arms 42 that point inwards and are pressed and tensioned outwards during connection until they can finally engage behind the undercut pin 32. The spring element 40 is thereby tensioned, with the tension being transferred to the entire spring geometry, and is then supported on one side by its base 41 against the support surface 34 and on the other side by the locking arms 42 against the rear surface of the pin 32. The spring element 40 is thus fixed in the z-direction (loosening is made difficult by the inner surfaces of the pockets 21), but can still move or shift in the transverse direction (x- or y-direction), as shown in Fig. 2b illustrated with the double arrow (see also Fig.3) The locking arms 42 act as guide elements. In the z-direction, the fastening effect is essentially determined by the force-fit between the connecting elements 30 and 40, and transversely to this, i.e., in the x- and y-directions, essentially by the positive fit.

Claims

[1] Traction battery (100) for an electric car or hybrid electric vehicle, comprising a housing and several battery modules (20) arranged in the housing and attached to the housing base (10), wherein the battery modules (20) are attached by means of plug connections, by means of undercut pins (32) arranged on the housing base (10) and locking clips (40) arranged on the undersides of the battery modules (20), which engage the pins (32) in a form-fit and force-fit manner, characterized by , that each battery module (20) is attached to the housing base (10) by three such plug connections and each plug connection has a translational degree of freedom lying in the mounting plane, wherein for each battery module (20) the degrees of freedom at its plug connections have different directions, such that the battery modules (20) can expand but cannot move. [2] Traction battery (100) according to claim 1, characterized by , that the battery modules (20) are attached at one of their lower edges by two plug connections arranged in the corners and at the opposite lower edge by a plug connection arranged in the middle. [3] Traction battery (100) according to any one of the preceding claims, characterized by , that the battery modules (20) have groove-like pockets (21) on their undersides in which the locking clips (40) are arranged. [4] Traction battery (100) according to any one of the preceding claims, characterized by that the locking clips (40) have an omega-shaped cross-section and two locking arms (42). [5] Traction battery (100) according to any one of the preceding claims, characterized by , that the locking clips (40) are made from sheet metal in one piece. [6] Traction battery (100) according to any one of the preceding claims, characterized by, that connecting elements (30) are provided which are attached to the housing base (10) and each have an undercut pin (32) which projects from the housing base (10). [7] Traction battery (100) according to one of the preceding claims, further comprising a control unit which is attached to the housing in an analogous manner.

Images