Motor vehicle battery

Abstract

Motor vehicle battery (10), in particular traction battery for the electric drive of a motor vehicle, with a battery base (12) for heat dissipation, a battery frame (18) connected to the battery base (12), at least one battery module (20) placed on the battery base (12) and inserted into the battery frame (18), wherein the battery module (20) has a plurality of battery cells, wherein the battery frame (18) is designed for fastening a battery cover or a retaining projection (22) for captively retaining the battery module (20) in the battery frame (18), and a thermal contact device (24) for thermally contacting both a lateral end face of the battery module (20) and a lateral longitudinal side of the battery module (20) with the battery frame (18), wherein the contact device (24) has individual contact elements (26) whose size corresponds to the respective associated side surface of the battery module (20).

Description

[0001] The invention relates to a motor vehicle battery with the aid of which a motor vehicle can be electrified and, in particular, a hybrid or battery-electric motor vehicle can be electrically driven.

[0002] DE 10 2011 015 152 A1 discloses a motor vehicle battery composed of several flat pocket battery cells. The individual pocket battery cells are connected to one another on their flat sides via a shock-absorbing damping element, which can be made of a plastic with thermally conductive filler materials.

[0003] From DE 10 2012 222 689 A1 it is known to insert battery cells of a motor vehicle battery into a cell holder that surrounds the battery cell at the bottom and partially at the sides, wherein the cell holder is placed on a cooling plate.

[0004] From DE 10 2010 013 012 A1, an energy storage device with several battery cells is known, in which the spaces between the battery cells are filled with a heat-conducting material.

[0005] There is a constant need to cool a motor vehicle battery.

[0006] The object of the invention is to show measures that enable good cooling of a motor vehicle battery.

[0007] The object is achieved according to the invention by a motor vehicle battery having the features of claim 1. Preferred embodiments of the invention are specified in the subclaims and the following description, which may each individually or in combination represent an aspect of the invention.

[0008] According to the invention, a motor vehicle battery, in particular a traction battery for the electric drive of a motor vehicle, is provided with a battery base for heat dissipation, a battery frame connected to the battery base, at least one battery module placed on the battery base and inserted into the battery frame, wherein the battery module has a plurality of battery cells, wherein the battery frame is designed for fastening a battery cover or a retaining projection for captively retaining the battery module in the battery frame, and a thermal contact device for thermally contacting both a lateral end face of the battery module and a lateral longitudinal side of the battery module with the battery frame, wherein the contact device has individual contact elements whose size corresponds to the respective associated side surface of the battery module.

[0009] The contact device enables heat generated in the battery module by the charging and discharging of battery cells to be dissipated via the side walls of the battery module to the battery frame. This utilizes the knowledge that the battery frame itself, which is made in particular from a metallic material, is also a good heat conductor and, with the help of the contact device, can be used at least as a passive cooler for the battery module. The battery module can therefore be cooled not only via the bottom with the help of the battery base but also via the side surfaces with the help of the contact device and the battery frame. If necessary, the battery module can be covered with an actively and / or passively cooled battery cover, so that the battery module can also be cooled via the top with the help of the battery cover.The contact device eliminates the need for a thermally insulating air gap between the battery module and the battery frame, allowing for improved heat dissipation via the battery frame. The contact device also allows the battery module to be cooled via its side surfaces, thus enabling a vehicle battery with effective cooling.

[0010] The battery module has a plurality of battery cells, which are configured in particular as flat pocket battery cells. The battery module is preferably substantially cuboid-shaped. Preferably, a plurality of pocket battery cells are arranged one behind the other, such that the plurality of smaller narrow sides of the pocket battery cells positioned next to one another correspond to a lateral longitudinal side of the substantially cuboid-shaped battery module, and the larger end sides arranged one behind the other correspond to a lateral narrow end side of the substantially cuboid-shaped battery module.With the help of the contact device, thermal contact can be achieved between the narrow sides of the pocket battery cells via the long side of the battery module, so that inner pocket battery cells can also be cooled more directly without the inner pocket battery cells having to conduct their heat to the ends of the pocket battery cells stacked one behind the other. This makes it possible to even out the temperature distribution within the battery module, thus avoiding temperature peaks that could impair efficiency. Preferably, the contact device is in thermal contact with all side surfaces of the battery module. For example, the contact device can encompass the battery module in a frame-like manner, thereby thermally contacting both end faces and both long sides of the battery module.The contact elements can be thermally coupled to one another via the battery frame, allowing local temperature differences to be compensated. Preferably, the contact elements are thermally coupled directly to one another. Contact elements that thermally connect different side surfaces of the battery module are particularly preferably designed as a single piece. The contact device can, for example, have angled contact elements.

[0011] The battery frame is designed so that a battery cover or a retaining projection for captively retaining the battery module in the battery frame can be preferably releasably attached to the battery frame, for example, by screwing. For this purpose, the battery frame can have a correspondingly large wall thickness, whereby the battery frame can simultaneously absorb a correspondingly large amount of heat and the cooling of the battery module is improved.

[0012] In particular, the contact device is made of a thermally conductive plastic material. The plastic material is, in particular, electrically non-conductive, so that an electrical short circuit between the individual battery cells via the contact device can be avoided. At the same time, the plastic material can have increased thermal conductivity, which allows the heat from the battery cells of the battery module to be dissipated. The thermal conductivity is, in particular, higher than that of air. Suitable materials and material properties of the plastic material are described in particular in paragraph 0020 of DE 10 2011 015 152 A1, the content of which is hereby incorporated by reference as part of the invention.

[0013] The plastic material preferably comprises thermally conductive and electrically non-conductive fillers, in particular hexagonal boron nitride. Additionally or alternatively, single- and / or multi-walled carbon nanotubes or similar fillers can be used as fillers, which can have a thermal conductivity of approximately 3000 W / mK and theoretically up to approximately 6600 W / mK. Such fillers can significantly increase the thermal conductivity, preferably without rendering the contact device electrically conductive.

[0014] Particularly preferably, the plastic material is configured as expanded foam. The plastic material can thus be easily compressed and allows for a flat contact with the battery module and / or the battery frame, which enables good heat transfer due to the flat contact. In particular, it is possible to first insert the battery module into the frame and place it on the battery base, and only then to fill the gap between the battery module and the battery frame with the plastic material.

[0015] In particular, a support structure, in particular a metal one, is incorporated into the plastic material to shape the contact device, wherein the support structure is in particular completely encased in the plastic material. The support structure can give the plastic material additional dimensional stability, which can, for example, prevent the contact device from accidentally buckling during assembly of the battery module. In addition, the support structure can easily distribute the absorbed heat over the entire extent of the contact device due to its own thermal conductivity, thereby promoting heat dissipation. The support structure is designed in particular as a grid, for example with struts running vertically and horizontally and intersecting each other in a contacting manner. In particular, the support structure is overmolded and / or foamed with the plastic material.

[0016] The contact device preferably has fastening pieces, in particular metallic ones, that engage in the battery frame for precise positioning within the battery frame. The fastening pieces can be designed, for example, as protruding projections that can be inserted into corresponding grooves in the battery frame. The fastening pieces can, in particular, partially protrude into a plastic material of the contact device and can be overmolded and / or foam-coated with the protruding part, preferably in a captive manner.

[0017] Particularly preferably, the contact device has a base piece for thermally connecting the battery module to the battery base. The contact device can thus be thermally coupled not only to the battery frame but also to the, preferably actively cooled, battery base. For example, the contact device can rest flat against the battery base with a bottom side facing vertically downwards. Cooling of the battery module is thereby improved.

[0018] In particular, the contact device is pressed between the battery module and the battery frame. The contact device is preferably elastically deformable, for example, in the form of foam. An air gap between the battery module and the battery frame can, in particular, form a press fit for the contact device. The pressed-in receptacle for the contact device allows for good thermal contact with low thermal transfer resistance.

[0019] Preferably, the battery frame is thermally coupled to the battery base for heat dissipation. This allows the heat component of the heat flow transferred from the contact device to the battery frame to be passed on to the battery base, which is in particular actively cooled. The battery frame and the contact device can thus be cooled via the battery base, which can increase the cooling performance.

[0020] Particularly preferably, the battery base has a cooling channel for cooling the battery module, wherein the cooling channel in particular has an inlet for supplying coolant and an outlet for discharging the coolant. The battery base can thus be actively tempered, in particular cooled, for example, with cooling water or cooling oil. The battery module can thus be tempered to a temperature range close to the optimal operating temperature.

[0021] The invention will be explained below by way of example with reference to the accompanying drawings using preferred embodiments, wherein the features presented below can represent an aspect of the invention both individually and in combination. They show: Fig. 1: a schematic sectional view of a first embodiment of a motor vehicle battery, Fig. 2: a schematic sectional view of a second embodiment of a motor vehicle battery and Fig. 3: a schematic sectional view of a third embodiment of a motor vehicle battery.

[0022] The Fig. The motor vehicle battery 10 shown in Figure 1, which is in particular a traction battery of a hybrid or battery-electric motor vehicle, has a battery base 12 with a cooling channel 14 through which a cooling liquid can be passed in order to control the temperature of the battery base 12, in particular to actively cool it.

[0023] The battery base 12 can be provided on its underside with a solid underbody protection 16, which can serve as impact protection, so that the battery base 12 can also serve as the underbody of the motor vehicle.

[0024] A battery frame 18 is placed on the battery base 12, into which a battery module 20 can be inserted and placed on the battery base 12. Retaining lugs 22 and / or a battery cover can be screwed to the battery frame 18 in order to securely retain the battery module 20 between the battery base 12 and the retaining lugs 22 in the battery frame 18.

[0025] The essentially cuboid-shaped battery module 20 is inserted into a contact device 24, which, in the illustrated embodiment, has a plurality of elastically compressible contact elements 26, largely made of a plastic material with good thermal conductivity. The contact elements 26 of the contact device 24 can each lie flat against the long and short side surfaces of the essentially cuboid-shaped battery module and the respective opposite part of the battery frame. In addition, one contact element 26 of the contact device 24 lies flat against an underside of the battery module and the battery base 12.The contact elements 26 of the contact device 26 can be pressed as side pieces between the battery module and the battery frame or as a base piece between the battery module 20 and the battery base with a press fit, so that good heat dissipation from the battery module 20 to the battery frame 18 and the battery base 12 can result via the contact device 24. The battery frame 18, which rests flat on the battery base 12, can also be cooled by the actively cooled battery base 12. In the illustrated embodiment, the contact elements 26 of the contact device 24 are spaced apart from one another and thermally coupled to one another only indirectly via the battery frame 18 and / or the battery base 12.

[0026] At the Fig. The embodiment of the motor vehicle battery 10 shown in Figure 2 is compared to the embodiment shown in Fig. In the embodiment of the motor vehicle battery 10 shown in Figure 1, the contact device 24 is designed as a single piece. The contact device 24 can form a receiving shell corresponding to the outer contour of the battery module 20, into which the battery module 20 can be inserted from above in the direction of gravity. Additionally, metallic, elongated fastening pieces 28 protrude slightly into the, for example, foamed plastic material of the contact device 24. These fastening pieces protrude outwardly from the battery module 20 and can engage in a corresponding groove in the battery frame 18. This allows the contact device 24 to be anchored precisely in the battery frame 18 and prevent it from accidentally bending when the battery module 20 is inserted into the contact device 24.

[0027] At the Fig. The embodiment of the motor vehicle battery 10 shown in Figure 3 is compared to the embodiment shown in Fig.In the embodiment of the motor vehicle battery 10 shown in Figure 2, a grid-shaped support structure 30 is overmolded with the plastic material of the contact device 24. This improves the mechanical stability of the contact device 24. At the same time, the heat within the contact device 24 can be better distributed thanks to the support structure 30, which is particularly made of metal.

Claims

[1] Motor vehicle battery (10), in particular traction battery for the electric drive of a motor vehicle, with a battery base (12) for heat dissipation, a battery frame (18) connected to the battery base (12), at least one battery module (20) placed on the battery base (12) and inserted into the battery frame (18), wherein the battery module (20) has a plurality of battery cells, wherein the battery frame (18) is designed for fastening a battery cover or a retaining projection (22) for captively retaining the battery module (20) in the battery frame (18), and a thermal contact device (24) for thermally contacting both a lateral end face of the battery module (20) and a lateral longitudinal side of the battery module (20) with the battery frame (18), wherein the contact device (24) has individual contact elements (26) whose size corresponds to the respective associated side surface of the battery module (20). [2] Motor vehicle battery (10) according to claim 1 characterized by that the contact device (24) is made of a thermally conductive plastic material. [3] Motor vehicle battery (10) according to claim 2 characterized by that the plastic material contains thermally conductive and electrically non-conductive fillers, in particular hexagonal boron nitride. [4] Motor vehicle battery (10) according to claim 2 or 3 characterized by that the plastic material is designed as expanded foam. [5] Motor vehicle battery (10) according to one of claims 2 to 4 characterized by that a, in particular metallic, support structure (30) for shaping the contact device (24) is introduced into the plastic material, wherein in particular the support structure (30) is completely enveloped by the plastic material. [6] Motor vehicle battery (10) according to one of claims 1 to 5 characterized by that the contact device (24) has fastening pieces (28) engaging in the battery frame (18), in particular metallic, for precise positioning in the battery frame (18). [7] Motor vehicle battery (10) according to one of claims 1 to 6 characterized by that the contact device (24) has a base piece for thermally contacting the battery module (20) with the battery base (12). [8] Motor vehicle battery (10) according to one of claims 1 to 7 characterized by that the contact device (24) is pressed between the battery module (20) and the battery frame (18). [9] Motor vehicle battery (10) according to one of claims 1 to 8 characterized by that the battery frame (18) is thermally coupled to the battery base (12) for heat dissipation. [10] Motor vehicle battery (10) according to one of claims 1 to 8 characterized by that the battery base (12) has a cooling channel (14) for cooling the battery module (20), wherein in particular the cooling channel (14) has an inlet for supplying coolant and an outlet for discharging the coolant.

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