Battery module with a ventilation channel

Abstract

Battery module (1), comprising: a cooling medium inlet (61) and a cooling medium outlet (62), between which a cooling medium (6) flows along a flow path during operation of the battery module (1), thus providing direct cooling of the battery module (1); wherein a stepped region (7) is arranged in the flow path, at which the cooling medium flow undergoes a deflection which is counter to directed towards the gravitational force; a venting channel (9) having an inlet and an outlet, wherein the inlet is arranged in the stepped region (7) and the venting channel (9) forms a venting flow path for a part of the flowing cooling medium (6) during operation of the battery module (1), which therefore does not experience the deflection that occurs at the stepped area (7).

Description

The present invention relates to a battery module having a vent passage around a stepped portion in the cooling medium flow path.Batteries with directly cooled battery cells are sufficiently known from the prior art. For example, document DE 10 2022 102 419 A1 discloses a battery module having a battery housing with a plurality of battery cells arranged within the battery housing and a temperature control channel arrangement through which a temperature control liquid can flow, wherein the temperature control channel arrangement has a plurality of feed channels spaced apart from one another and a plurality of discharge channels spaced apart from one another.Depending on the design of the cooling medium channels in a battery module, which define the flow path of the cooling medium through the battery module, it may occur that the cooling medium meets an offset or a stepped region and has to flow around the latter. During operation, air bubbles located in the cooling medium can now collect at this offset in the upper region and form a dead region from which the cooling medium is displaced. As a result, the cooling effect is greatly reduced or completely absent in the dead zone. The dead zone may develop into an undesirable heat build-up point.Document DE 10 2022 108 833 B3 discloses a battery device for a vehicle, in particular an electric vehicle, having at least two battery cells and a busbar, which are arranged in an interior of a battery housing and can be temperature controlled by a flowable coolant arranged in the interior. The busbar and a deflecting element are arranged in an intermediate space between the battery cells, wherein the deflecting element has at least one passage opening for the coolant, which is arranged in such a way that coolant flowing through the passage opening flows along the busbar.Against this background, the object of the invention can be seen in providing a battery module in which the formation of such dead points can be avoided.This object is achieved by means of the subject matter of the independent claims. Further preferred embodiments are found in the dependent claims.According to the invention, a battery module is provided having a cooling medium inlet and a cooling medium outlet, between which a cooling medium (e.g. a dielectric cooling oil) flows along a flow path during operation of the battery module and thus provides direct cooling of the battery module. The flow path may be defined by clearances between the battery cells disposed within the battery module. In other words, the battery module according to the invention is one with direct cooling.In the flow path provided within the battery module according to the invention, an offset (e.g. a Z offset) or stepped region is arranged, at which the cooling medium flow experiences a deflection which is directed substantially counter to the force of gravity. This deflection direction can be understood to mean a deflection of the cooling medium flow directed downward essentially in the installation position of the battery module in a corresponding battery (which is in turn arranged in the installation position, e.g. in a vehicle). The deflection can be caused in particular by a component arranged in the cooling medium path in the interior of the battery module. When the coolant flows through the battery module, the coolant flows against the stepped region and is pressed / deflected downward. The stepped region can be an offset, the surfaces of which meet at an angle of substantially 90°.The battery module according to the invention has a venting channel in order to vent the fluidic dead region formed at the stepped region. The venting channel has an inlet and an outlet, wherein the inlet is arranged in the stepped region and the venting channel forms a venting flow path for a part of the flowing cooling medium during operation of the battery module, which as a result does not undergo the deflection effected at the stepped region. The venting channel can in particular represent a bypass running parallel to a main flow, which bypass conducts a part of the flowing cooling medium around the stepped region. The main flow can be understood to mean the cooling medium flow before the cooling medium meets the stepped region. The venting channel can, for example, guide a portion of the cooling medium around the stepped region, wherein the cooling medium flowing through the venting channel experiences no loss of height between the inlet and the outlet (with respect to the installation position of the battery module). Viewed in cross section perpendicular to the main flow, the flow path through the venting channel can correspond to a straight continuation of the main flow.The venting channel can be designed such that it can run substantially parallel to the cooling medium flow and during operation of the battery module a continuous flow can be established through it substantially parallel to the main flow. Because the inlet of the venting channel is located in the upper region of the offset, for example at the bending line of the offset, air bubbles accumulating here are conducted through the venting channel and are conducted on again after / after the offset into the main flow of the cooling medium after the offset.From the perspective of the invention, a gradient of the venting channel between inlet and outlet is not problematic for achieving venting of the dead zone and is to be contained within the scope of the wording "substantially" parallel to the main flow. The venting channel can be formed such that there are no edges / creases on its upper wall along the venting flow path, at which edges air bubbles can collect.According to further embodiments of the battery module, the venting flow path can run along a direction which is substantially parallel to the flow direction of the cooling medium before reaching the stepped region.According to further embodiments of the battery module, the inlet of the venting channel can be arranged in a corner region of the stepped region. In other words, the inlet of the venting channel can be arranged at the bending line in an upper boundary surface of the flow path of the cooling medium, which boundary surface forms the step or the offset.According to further embodiments of the battery module, the inlet of the venting channel can adjoin a surface which delimits the flow path of the cooling medium in the upward direction in the stepped region. In this case, the surface delimiting the flow path upward (e.g. inner wall of the housing of the battery module) can transition without buckling / offset into a surface delimiting the venting duct flow path upward.According to further embodiments of the battery module, the stepped region can be formed by a busbar arranged in the flow path of the cooling medium or a connector which connects a battery cell arranged in the battery module to a terminal of the battery module. This region is surrounded by the cooling medium. The stepped region disturbing the fluid flow can result from the flow around this region intended for cooling purposes and from the arrangement of the surrounding components (e.g. busbars, housings, flow bodies, HV connections, etc.).According to further embodiments of the battery module, the outlet of the venting channel can be arranged behind the busbar or the connector. Consequently, the venting channel can function as a bypass, which conducts a part of the cooling medium substantially "level-maintaining" around the stepped region or the offset with respect to the coolant flow.According to further embodiments of the battery module, the stepped region can be arranged in a corner region of a housing of the battery module.According to the invention, a battery module arrangement is also provided which has at least two battery modules described above. During operation of the battery, the flow path of the cooling medium can extend through the at least two battery modules, wherein the cooling medium flows into the second battery module after leaving the first battery module. The battery module arrangement may be arranged in particular in a housing of a battery, e.g. of a traction battery of an electric vehicle.According to a further embodiment of the battery, the outlet of the venting channel of one of the battery modules can be arranged in the other battery module, so that the venting channel forms a flow path for the cooling medium between the two battery modules.It is understood that the features mentioned above and those still to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings. FIG. 1 shows an exemplary battery module according to the present invention. FIG. 2 shows an exemplary battery module arrangement according to the present invention.In FIG. 1, an exemplary battery module 1 according to the present invention is shown in a cross-sectional view. In an elongate battery module housing 2, two battery cells 31, 32 are arranged one behind the other (along the Y direction). Arranged centrally in the battery module housing 2 are HV connectors 5, at which the voltage can be tapped from the outside. In this region, the busbars / connectors 4 are located in the interior of the battery module 1, which connect the HV dockers 5 to the battery cells 31, 32. In the example shown, the battery cell 32 arranged on the left side is connected to one of the HV connectors 5 of the battery module 1 by means of an electrical connector 4.The battery module 1 is a directly cooled battery module 1, in which during operation of the battery module according to the invention a coolant 6 flows through the interior of the battery module 1 and thus cools the battery cells 31, 32. The coolant inlet 61 is located on the one side wall of the battery module housing 2 and the coolant outlet 62 is located on the opposite side wall of the battery module housing 2.The region in which the busbars and / or connectors 4 are arranged is also surrounded by the cooling medium 6 for cooling purposes. Due to the flow around and the arrangement of components (busbars, housings, flow bodies, HV connections, etc.), the cooling medium must flow around a stepped region 7.The stepped region 7 is formed by the upper inner wall of the battery module housing 2 and the HV plug 5 and is distinguished by a substantially perpendicular bending of the upper delimiting surface for the flow path of the cooling medium. At the bending edge within the stepped region, a dead region 8 or an air bubble collecting region is formed. Here, the air bubbles present in the cooling medium 6 may accumulate, so that a displacement effect of the cooling medium 6 may occur in this dead zone 8.In order to prevent the accumulation of air bubbles and thereby prevent the formation of the dead zone 8, a venting channel 9 is provided in the battery module 1, which venting channel has an inlet and an outlet, wherein the inlet is arranged in the stepped region or, in other words, in the inflow region of the stepped region 7. During operation of the battery module 1, the venting channel 9 provides a venting flow path for a part of the flowing cooling medium 6, which does not undergo the deflection effected at the stepped region 7. The predominant portion of the cooling medium 6 is thus deflected downward in the stepped region 7, while a small portion of the cooling medium 6 is directed around the stepped region 7. At the outlet of the venting channel 9, which is arranged in the outflow region behind the stepped region, this smaller portion of the cooling medium 6, which due to the buoyancy force of air bubbles is very likely to carry it with it, is introduced back into the main flow of the cooling medium 6.FIG. 2 shows an exemplary battery module arrangement according to the present invention in a cross-sectional view, which has two battery modules 1. Basically, except for a different arrangement of the stepped region 7, each of the battery modules 1 can be the battery module 1 illustrated in FIG. 1. Therefore, the same components are given the same reference numerals and will not be described in detail again. The view of a battery module 1 shown in FIG. 2 corresponds to a view rotated through 90° into the plane of the sheet compared to the view in FIG. 1.As shown in FIG. 2, the venting channel 9 can be inserted within a battery module arrangement present in an HV battery, wherein venting takes place between battery modules 1. In this case, the outlet of the venting duct 9 of the left of the two battery modules 1 is arranged in the other, here right battery module 1, such that the venting duct 9 forms a flow path for the cooling medium 6 between the two battery modules 1. The stepped region 7 is located in a corner of the battery module housing 1 The venting channel 9 can be formed as a corresponding line which connects the two battery modules 1 to one another.

Claims

A battery module (1) comprising: a cooling medium inlet (61) and a cooling medium outlet (62), between which a cooling medium (6) flows along a flow path during operation of the battery module (1) and thus provides direct cooling of the battery module (1); wherein a stepped region (7) is arranged in the flow path, at which the cooling medium flow experiences a deflection directed counter to the force of gravity; a venting channel (9), which has an inlet and an outlet, wherein the inlet is arranged in the stepped region (7) and the venting channel (9) forms a venting flow path for a part of the flowing cooling medium (6) during operation of the battery module (1), which as a result does not experience the deflection effected at the stepped region (7).The battery module (1) according to claim 1, wherein the venting flow path extends along a direction parallel to the flow direction of the cooling medium (6) before the stepped portion (7).Battery module (1) according to claim 1 or 2, wherein the inlet of the venting channel (9) is arranged in a corner region of the stepped region (7).Battery module (1) according to one of Claims 1 to 3, wherein the inlet of the venting duct (9) adjoins a surface which delimits the flow path of the cooling medium (6) in the stepped region (7) in the upward direction.The battery module (1) according to any one of claims 1 to 4, wherein the stepped portion (7) is formed by a bus bar disposed in the flow path of the cooling medium (6) or a connector (4) connecting a battery cell (32) disposed in the battery module (1) to a terminal (5) of the battery module (1).The battery module (1) according to claim 5, wherein the outlet of the venting channel (9) is arranged behind the busbar or the connector (5).The battery module (1) according to any one of claims 1 to 4, wherein the stepped portion (7) is disposed in a corner portion of a case (2) of the battery module (1).A battery module arrangement, comprising: at least two battery modules (1) according to any one of claims 1 to 7.The battery module arrangement according to claim 8, wherein the outlet of the venting channel (9) of one of the battery modules (1) is arranged in the other battery module (1) such that the venting channel (9) forms a flow path for the cooling medium (6) between the two battery modules (1).

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