Housing for galvanic element

Abstract

Housing (10) for at least one galvanic element (14), in particular at least one battery cell, comprising a pressure equalization device (22) and a temperature control device (16) for cooling and / or heating the at least one galvanic element (14) in the housing interior (12), wherein a temperature control fluid flows through the temperature control device (16), characterized in that the pressure equalization device (22) comprises at least one inlet valve (26), an outlet opening (36), an opening (32) into the housing interior (12) with a selectively permeable membrane (44) and is in thermal contact with the temperature control device (16).

Description

State of the art

[0001] The present invention relates to a housing for at least one galvanic element, in particular at least one battery cell, comprising a pressure equalization device with a dehumidification device for reducing condensate formation in the interior of the housing.

[0002] In automotive technology, electrical energy storage devices, particularly electrochemical energy storage devices such as high-capacity lithium-ion batteries, are increasingly being used as drive sources in electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid vehicles (PHEVs), and / or fuel cell vehicles. Due to their high specific energy density and low self-discharge, they are suitable as traction batteries. To achieve the required performance and energy data, individual electrochemical energy storage devices, also known as accumulators, are connected in series and / or parallel. With an optimal system design, total voltages (e.g., nominal voltage or maximum voltage) are achieved that are typically in the range of 100 to 1000 V.However, during charging and discharging, significant temperature increases sometimes occur, which significantly impact the aging process and thus the service life of the batteries. To ensure sufficient operational reliability, a service life of more than ten years, and the provision of power from the batteries, a specific temperature range must be maintained during operation, particularly for lithium-ion batteries in the range of -40°C to +60°C, which necessitates air conditioning. Air conditioning, i.e., cooling or heating, is essentially achieved by means of targeted airflow and / or a cooling system, generally based on water / glycol.

[0003] A housing housing at least one galvanic element, in particular at least one battery cell, protects it from environmental influences and ensures electrical insulation. In addition to the battery modules and a cooling system designed as a temperature management system, power electronics and electrical lines for controlling the battery modules are also arranged. Such housings are essentially airtight, with pressure equalization between the interior and the environment being provided. In particular, pressure equalization elements (pressure balancing units, PBUs) are provided, which ensure pressure equalization via pressure equalization openings once a certain differential pressure has been reached between the interior of the housing and the environment.The moisture contained in the incoming air can condense inside the housing, especially at lower internal temperatures than the ambient temperature, and possibly cause damage to the live components.

[0004] DE 10 2009 058 880 A1 relates to an electrical energy storage system arranged in a housing arrangement, which has an air exchange passage with a dehumidification device. The moisture is removed in a cooled air duct through condensation drying, forming condensate, which flows outward due to gravity. The cooling system includes, for example, a heat exchanger, which is a component of a coolant circuit that can also be used to cool other components. A disadvantage of this system is that the condensate formed only flows outward by gravity through an opening, which simultaneously serves as the air inlet and is therefore susceptible to clogging and contamination.

[0005] DE 10 2009 054 921 A1 relates to a method and a device for reducing the humidity of a gas in the interior of a battery housing. The gas enters a space through a first selectively permeable membrane, in which a cooling device is provided, for example, at least one Peltier element or a component of a cooling system arranged in the interior of the battery housing, by means of which the incoming gas - ambient air - is cooled and moisture is removed. The cooled gas, with a reduced water vapor content, enters the interior of the housing through a second selectively permeable membrane, impermeable to liquids. The condensate is released into the environment via a check valve. A disadvantage of this device is that it does not constitute a pressure equalization element for the controlled inflow of gas.

[0006] The state of the art in this regard continues to be the documents EP 2 641 285 B1, DE 10 2010 051 013 A1 and DE 10 2010 022 327 A1.

[0007] The object of the present invention is to dry air flowing into a housing for at least one galvanic element in a simple and reliable manner.

[0008] This object is achieved with a housing having the features of claim 1 and a motor vehicle having the features of claim 10. Disclosure of the invention

[0009] According to the invention, a housing for at least one galvanic element, in particular at least one battery cell, is proposed, comprising a pressure equalization device and an active temperature control device for cooling and / or heating the at least one galvanic element in the housing interior, wherein a temperature control fluid flows through the temperature control device. A housing is understood to be a device that has an interior space suitable for accommodating components and completely separating them from the environment. The housing is preferably designed to be airtight and comprises air-permeable openings provided in the pressure equalization device solely for the purpose of pressure equalization between the housing interior and the environment. The pressure equalization device comprises at least one inlet valve, one outlet opening, and a selectively permeable membrane as an opening into the housing interior.Furthermore, the pressure compensation device is in thermal contact with the temperature control device, wherein a dehumidification device is provided.

[0010] The temperature control device comprises sections for controlling the temperature of the elements arranged in the housing, in particular a number of galvanic elements. Galvanic elements are to be understood in particular as electrochemical energy storage devices, such as battery cells, which store energy by means of electrochemical processes and make it available again when needed. In principle, battery cells of any accumulator or battery cell type can be accommodated in the housing according to the invention. For example, these are battery cells of the types lithium-ion cells, lithium polymer cells, lithium metal cells and similar, which are functionally combined as battery cells, battery modules and / or as a battery pack. One or more battery cells or one or more battery modules can be accommodated in the housing according to the invention, wherein the battery modules each have a number of battery cells.Furthermore, the individual battery cells can be electrically connected to one another in such a way that they are arranged to form battery modules or battery packs. Furthermore, components, such as a battery management system for controlling or regulating battery behavior, can be accommodated in the housing. The temperature control of such electrochemical energy storage devices is advantageously implemented within the scope of the invention via a temperature control circuit.

[0011] When there is a corresponding pressure difference between the interior of the housing and the environment, air flows from the environment into the housing via an inlet valve of the pressure equalization device. The incoming air contains a proportion of water vapor depending on its temperature. The incoming air enters the pressure equalization device, or into a space between the inlet valve and an opening in the interior of the housing, which opening is formed by a selectively permeable membrane. In this space, the incoming air comes into thermal contact with the temperature control device, in particular with an inlet area of ​​the temperature control liquid. When the incoming air cools, a proportion of the water vapor in the air condenses, resulting in the formation of condensate. The cooled air, which has a lower humidity, enters the interior of the housing via the opening, or rather the selectively permeable membrane provided therein, and the resulting condensate is drained away beforehand.Such a membrane is preferably a selectively permeable membrane. A selectively permeable membrane arranged in the opening to the interior of the housing, which is permeable to air but impermeable to water, essentially prevents the direct passage of liquid.

[0012] In a preferred embodiment, the opening provided with the selectively permeable membrane is located inside the housing above the outlet of the pressure equalization device. Due to gravity, any condensate that accumulates collects below the opening into the housing interior, for example, in a collecting reservoir, and flows out through the outlet. The opening into the housing interior, positioned above the outlet, ensures that the collected condensate does not reach the interior of the housing.

[0013] The accumulated condensate can be collected in a region of the pressure equalization device designed as a collecting reservoir and drained via a suitably arranged outlet, or drained at intervals. For this purpose, according to the invention, a closable opening is provided on the collecting reservoir, which can be closed, for example, by means of a screw plug or a plug. By opening the screw plug or the plug, for example during servicing, the collected condensate can be drained. In one embodiment, an outlet valve is arranged at the outlet of the pressure equalization device, for example in a lower region of the collecting reservoir. If the pressure in the housing is higher than the ambient pressure, the accumulated and collected condensate can be blown out via the outlet valve, for which a control and / or regulating device is provided.

[0014] The housing according to the invention is designed such that the pressure equalization device is in direct thermal contact with the temperature control device, in particular with an inlet area of ​​the temperature control fluid into the temperature control device. The temperature control fluid is therefore initially used to cool incoming air containing a water vapor content in the event of pressure equalization between a lower pressure inside the housing and a higher ambient pressure. In this case, the cooling causes a condensation of a water vapor content of the air, which is thus dried. Since the temperature of the temperature control fluid is lowest at the inlet area of ​​the temperature control device, the incoming air is effectively cooled and dried. The cooled and dried air enters the housing interior and largely only comes into contact with components inside the housing that have a higher temperature.This prevents condensation from forming on components housed in the housing. Furthermore, it ensures that condensation forms locally in the pressure equalization device or dehumidification device according to the invention and not inside the housing.

[0015] To improve the thermal contact between the incoming air to be dried and the temperature control device in the pressure equalization device, the inlet area of ​​the temperature control device is designed as a heat exchanger. Furthermore, means for increasing the surface area can be provided in the area of ​​the heat exchanger. The most effective drying of the air can be supported by a suitable choice of the material for the temperature control device, which is characterized in particular by good thermal conductivity. Furthermore, an increase in the surface area of ​​the contact surfaces between the air to be cooled and the temperature control device can support effective drying. For example, the inlet area of ​​the temperature control device, in particular, can additionally have ribs, grooves, walls, vanes and / or webs or other surface enlargements.

[0016] The present invention also relates to a motor vehicle comprising a battery pack accommodated in a housing according to the invention. The motor vehicle and the battery pack accommodated in the housing according to the invention are in functional contact; for example, the battery pack represents part of a traction battery for an electric drive of a vehicle. Advantages of the invention

[0017] The solution proposed by the invention is characterized in that the housing for at least one galvanic element, in particular a battery cell, is designed in such a way that essentially only air enters the housing via the pressure equalization device for pressure equalization, whereby the volume flow is significantly reduced. At a certain pressure difference between the interior of the housing and the surroundings, the inlet valve of the pressure equalization device can be opened by means of a control or regulating device.

[0018] The air flowing into the pressure equalization device is cooled in a simple and reliable manner such that the air is dried while condensation forms. Advantageously, a temperature control device is used for this purpose, which is already provided in the housing for temperature control of the battery cells. In particular, it is advantageous that the air is cooled by means of the temperature control fluid entering the temperature control device, whereby the temperature control fluid - in the case of cooling - has the lowest temperature of the circuit in the inlet area. This ensures that the air entering the housing interior does not cool further on the components located there, and condensation on components inside the housing is avoided.

[0019] Condensation occurs specifically in the pressure equalization device, particularly in a dehumidification device that is advantageously integrated into the housing. This allows the condensate to be collected in a separate area and drained in a targeted manner. A particularly advantageous feature is the controlled or regulated drainage of the condensate via an outlet valve of the pressure equalization device, so that a battery accommodated in a housing according to the invention can be installed in a motor vehicle even in inaccessible locations. The dehumidification of the air is largely maintenance-free, so that corresponding housings with pressure equalization devices can also be installed in difficult-to-access areas of an electric vehicle, since they are maintenance-free and accessibility is therefore not required. Short description of the drawings

[0020] Further advantages and embodiments of the objects according to the invention are illustrated by the drawings and explained in more detail in the following description.

[0021] They show: Fig. 1 shows a representation of a housing according to the invention; Fig. 2 shows a further embodiment of a housing according to the invention. Versions

[0022] From the representation according to Fig. 1 shows a housing 10 according to the invention for at least one galvanic element, for example a battery cell 14.

[0023] The housing 10 encloses a housing interior 12, in which, in the illustrated embodiment, a number of battery cells 14 are arranged. Furthermore, a temperature control device 16 is provided in the housing interior 12, comprising, for example, a cooling plate through which a temperature control fluid flows. According to the illustration in Fig. 1, an inlet of the temperature control fluid into the temperature control device 16 is designated by reference numeral 18. The temperature control device 16, which is assigned to the battery cells 14, enables a supply of heat to the battery cells 14 and / or a removal of heat from the battery cells 14. In particular, in the Fig. In the embodiment shown in Figure 1, a cooled temperature control fluid flows through the temperature control device 16, although an outlet from the temperature control device 16 is not shown. At the inlet 18 of the temperature control fluid, a region 20 designed as a heat exchanger is formed. The heat exchanger region 20 is in thermal contact with a pressure equalization device 22 integrated in or on the housing 10, which includes a dehumidification device 24. The pressure equalization device 22 comprises an inlet valve 26, which opens in a controllable or adjustable manner when there is a pressure difference between the housing interior 12 and the surroundings, so that ambient air enters the pressure equalization device 22.

[0024] As in Fig. 1, the ambient air with a certain temperature and a water vapor content enters the pressure equalization device 22, in particular into an intermediate space 28, which - as shown - is located within the housing 10. The intermediate space 28 is delimited from the housing interior 12 by walls 30, wherein an opening 32 to the housing interior 12 is provided. The opening 32 comprises a selectively permeable membrane 44, wherein air can pass from the intermediate space 28 into the housing interior 12. Furthermore, it can be seen that in the Fig. 1, the heat exchanger region 20 of the temperature control device 16 is provided in the intermediate space 28, so that the air entering through the inlet valve 26 is in thermal contact with this heat exchanger region 20. The thermal contact of the incoming ambient air extracts heat from it, whereby, as the temperature drops, the saturation limit of water vapor in the air is exceeded and condensation occurs. The air, thus cooled and dried, then passes through the selectively permeable membrane 44 of the opening 32 into the housing interior 12. The fact that the opening 32 comprises the selectively permeable membrane 44, which is permeable to air but impermeable to liquid, ensures that condensate accumulating in the intermediate space 28 cannot enter the housing interior 12. The condensate formed therefore initially remains in the intermediate space 28.In one embodiment, the pressure equalization device 22 comprises a collecting reservoir 34 in which condensate collects.

[0025] In particular, the selectively permeable membrane 44 of the opening 32 is located above the collecting reservoir 34 and above an outlet opening 36, through which the collected condensate can be discharged. In particular, the outlet opening 36 can be designed as an outlet valve 38, so that the discharge of the condensate is controlled or regulated. A corresponding control and / or regulating unit is not shown.

[0026] From the presentation of the Fig. 2 shows a further embodiment of the housing 10 according to the invention, wherein in particular the area of ​​the pressure compensation device 22 is shown.

[0027] The temperature control fluid enters the heat exchanger region 20 of the temperature control device 16 via the inlet 18, wherein, in particular, an area provided as a heat exchange surface is enlarged. In particular, the heat exchanger region 20 is provided with fins, although walls, vanes, webs, or other surface-enlarging geometries 40 are also conceivable.

[0028] A lower portion of the pressure equalization device 22 is designed as a collecting reservoir 34 in which condensate is collected. Fig. In the embodiment shown in Figure 2, the outlet opening 36 of the pressure compensation device 22 is designed as an opening which is closed by a screw plug 42.

[0029] By the embodiments proposed according to the invention according to the Fig. 1 and Fig.2 - as described above - the inflow of larger quantities of moisture contained in the ambient air into the housing interior 12 of the housing 10, in which at least one galvanic element, preferably a number of electrically interconnected galvanic elements 14 are accommodated, can be effectively prevented. This contributes to increased safety during operation of a partially electrically powered vehicle. With the solution proposed according to the invention, incoming air is dried, i.e. its humidity is reduced. This is achieved according to the solution proposed according to the invention by the structural separation of a small area, i.e. the intermediate space 28, in which the collecting reservoir 34 and the heat exchanger area 20 are accommodated, from the housing interior 12 of the housing 10, in which the number of galvanic elements 14 in the form of battery cells are accommodated.In the pressure equalization device 22 separated from the housing 10, in the section of the temperature control device 16 designed as a heat exchanger area 20, surface enlargements 40 in the form of ribs, webs, corrugations, or the like are arranged. These enlargements are thus connected to the same cooling circuit as the temperature control device 16. Due to the cooling of the incoming air volume and the condensation of the water vapor contained in the incoming air volume, the moisture storage capacity of the air is significantly reduced. Condensate drips downward into the collecting reservoir 34, which forms in the bottom of the intermediate space 28 separated from the housing interior 12 and collects there. As soon as the dried air expands within the housing 10 due to heating of the galvanic elements 14, for example, battery cells, the condensate is forced outward through the outlet valve 38 and leaves the intermediate space 28.

Claims

[1] Housing (10) for at least one galvanic element (14), in particular at least one battery cell, comprising a pressure equalization device (22) and a temperature control device (16) for cooling and / or heating the at least one galvanic element (14) in the housing interior (12), wherein the temperature control device (16) is flowed through by a temperature control fluid, characterized by that the pressure compensation device (22) comprises at least one inlet valve (26), an outlet opening (36), an opening (32) into the housing interior (12) with a selectively permeable membrane (44) and is in thermal contact with the temperature control device (16). [2] Housing (10) according to claim 1, characterized by that the opening (32) of the pressure compensation device (22) into the housing interior (12) is arranged above the outlet opening (36) of the pressure compensation device (22). [3] Housing (10) according to one of claims 1 or 2, characterized bythat the pressure compensation device (22) is in thermal contact with an inlet area (18) of the tempering fluid into the tempering device (16). [4] Housing (10) according to one of claims 1 to 3, characterized by that the pressure compensation device (22) is in thermal contact with the temperature control device (16) via an inlet region (18) designed as a heat exchanger region (20). [5] Housing (10) according to claim 4, characterized by that the inlet region (18) of the temperature control device (16), designed as a heat exchanger region (20), has a surface enlargement (40), in particular designed as ribs, grooves, wings, walls and / or webs. [6] Housing (10) according to one of claims 1 to 5, characterized by that the pressure compensation device (22) comprises a collecting reservoir (34) for collecting condensate, which is separated from the housing interior (12). [7] Housing (10) according to claim 6, characterized bythat the collecting reservoir (34) comprises a closable outlet opening (36) for draining the condensate. [8] Housing (10) according to claim 6, characterized by that the collecting reservoir (34) comprises an outlet valve (38) through which the condensate is pushed outwards. [9] Housing (10) according to one of claims 1 to 8, characterized by that a control and regulating unit is included, wherein the inlet valve (26) and / or the outlet valve (38) can be controlled and / or regulated in accordance with a pressure difference between the housing interior (12) and the environment. [10] Motor vehicle comprising a housing (10) according to one of claims 1 to 9.

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