Heat system for a battery electric vehicle

Abstract

The invention relates to a support housing for a battery compartment of an electrically driven vehicle, by using flat metal sheets as deep-drawn housings that are assembled into each other, whereby at least one double floor is formed, into which a passive and partially integrated thermal management system for cooling and heating is integrated. The invention also relates to the integration of further functional elements, such as sensors for state measurement, which are integrated into the "double floor" and connected with the battery management system.

Description

[0001] The invention relates to a support housing for a battery compartment of an electrically driven vehicle, by using flat metal sheets as deep-drawn casings assembled into each other, whereby at least one double floor is formed, into which a passive and partially integrated thermal system for cooling and heating is integrated. The invention also relates to the integration of further functional elements, such as sensors for state measurement are integrated into the "double floor" and connected with the battery management system.

[0002] Parallel to the development of automobiles with internal combustion engines at the end of the 19th century, researchers also succeeded in developing electrically driven vehicles, such as Werner von Siemens and his electrically driven carriage (1882). Due to the significantly extended range, the availability and price of fossil fuels and the fast refueling process, passenger automobiles with internal combustion engines dominated in the 20th century. With the end of the 20th century and changing framework conditions, such as the increasing and limited availability of fossil fuels, electrically driven vehicles experienced a revival.

[0003] Generally, electrically driven vehicles use electrical drives combined with an integrated energy store as a drive concept. Depending on the respective drive concept, electrically driven vehicles can be divided into pure electric vehicles (BEV) using only electrical power and hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV) or range-extended electric vehicles (REEV) combining an electric motor with an internal combustion engine. In addition, fuel cell vehicles (FCV) or fuel cell hybrid vehicles (FCHV) are another class of electrically driven vehicles, in which chemical stored energy in the form of hydrogen is converted into electrical energy. As energy storage system, high-voltage batteries (accumulators) such as lithium-ion batteries are used as basic battery cells and then interconnected to modules. The various modules are assembled to the final vehicle battery. The vehicle battery is protected by a battery compartment (also called battery housing, battery pack, battery box or battery cover).

[0004] Besides increasing the battery range and how to protect the battery in case of a crash and intrusion, the topic of integrating further functions becomes more and more important, like a thermal management system or sensor technology for measuring the surrounding conditions and the battery status. In the background is the degree of efficiency of temperature-sensitive lithium-ion drive batteries of 95%. The remaining 5% represents lost heat and has to be drawn off, especially at higher ambient temperatures or during high-voltage loads, because at battery temperatures of more than 35°C the charging capacity of the battery is reduced and the aging process is accelerated. In the background is that the degradation of the battery chemistry is accelerated and shortens the component life. There is a direct relationship between temperature and chemical reactions: the higher the temperature, the faster the reaction. It is known from prior art battery electric vehicles that more than 18,000 battery cells are integrated into a battery compartment, which increases the lost heat. Generally, there are two ways of forming a cooling system: a direct cooling system integrated into the battery compartment and having a direct, more effective contact with the battery cells or battery modules, as known from US patent application 8758924B2, in which cooling tubes are inserted between different battery cell rows, thus being in direct contact with them. Another way of providing a cooling system would be an indirect cooling system, which surrounds the battery compartment and thus indirectly cools the entire compartment, so that there is no risk of short circuits in case of a leak. The advantage of the second design is that, for example, during repair cases or to replace components, easier access is given. In addition, there is also no direct contact between the cooling medium, such as water, during a crash case, which means that the systems are separated from each other. Different systems are distributed in the prior art in terms of the cooling medium: air cooling or liquid cooling with different kinds of fluids, such as water, coolant or refrigerant.

[0005] But cooling is not the only requirement regarding temperature: In addition with temperatures below 15°C the charging capacity of the battery is reduced and the battery behavior is sluggish, which means that the chemical reactions are slowed down, so that charging and discharging takes longer. Therefore, a heating system is also necessary. The complete temperature measurement and control system is called thermal management. The ideal temperature of the battery, which the thermal management aims at, can be defined between 15°C and 35°C, more preferably between 20°C and 30°C.

[0006] US patent application publication US2012 / 0141851 discloses a package for an energy storage device, particularly an electrochemical cell. The enclosure is configured to house at least one electrochemical cell at operating temperatures greater than about 100 degrees Celsius, such as between 250 degrees Celsius and 400 degrees Celsius, or between 400 degrees Celsius and 700 degrees Celsius.

[0007] Generally, depending on the location of the cooling system and the contact with the battery module, the thermal systems for heating and / or cooling the battery module can be divided into direct systems and passive systems. WO patent application 2012126111A1 describes an active direct cooling system, where the battery module is sandwiched with a system of battery cell coolers. US patent application 2013143093A1 provides a similar principle using a direct cooling system. Another type of direct cooling system is pointed out in WO patent application WO2016056774A1. The main disadvantage of direct cooling systems is the case of a leak occurring during the fluid can be in direct contact with the battery under current, with the potential risk of a short circuit of the battery and a fire. In addition, the accessibility is more challenging, for example during repair situations. Moreover, after a crash or impact situation, the individual compartments enable a faster replacement of individual components without causing an overall damage to the complete system.

[0008] An example of a passive, indirectly working thermal system can be given with WO patent application WO2005080902A1, where an attachment means on the upper surface is designed with an internal tube of a cover plate cooling (but not heating). Another example of a cooling plate is mentioned in WO patent application 2016096329A1, where in this case the cooling plate is intended as a mounting plate. In addition, US patent application 2015244044A1 also describes a type of cooling plate, in this case called a thermal plate manifold. Complementarily, DE patent application 102008059947A1 describes a heat conducting plate in connection with a single battery cell. US patent application 2017047624A1 points out a monolithic body, side walls or fluid channels within the base optionally added with cooling ribs. In addition, the last mentioned patent application can be classified according to the subject of cooling plates. Such plates have the disadvantage of being material intensive, which leads to a large weight of the complete battery system and indirectly reduces the battery range. In addition, there is a high waste of material, since the channels are manufactured from the complete material of the monolith. The overall volume of the cooling channels behind represents waste material.

[0009] Another way of manufacturing such cooling plates is to form them as cast parts, which are constructed with integrated channels. One example can be given with DE patent application 102015217810A1.

[0010] Furthermore, the battery compartment has to be assembled in a certain way: any kind of contaminant (like dust, dirt or other particles, but also gases and moisture) must not be able to penetrate into the compartment and thus damage the battery cells, leading to short circuits causing a fire. US patent application 2010136402A1 proposes a sealed battery package, whereby an impermeable sealing gasket is interposed between two housing members to seal the battery cells inside from the outside environment. In addition, a plurality of bolts fix the system from the outside of the sealing gasket. Another way is described in WO patent application 2018029020A1, where support protrusions are used to solve the problem regarding electromagnetic compatibility in a special viewing angle. In addition, WO patent application 9726782A2 refers to a sealing element with electrically conductive properties and in a coated condition. Such special elements are cost-intensive and difficult to implement into large industrial bulk vehicles.

[0011] To protect the battery cells inside the battery compartment, the manufacturing and assembly of such a compartment also has to be performed by focusing particularly on unwanted particles inside the compartment. The process of heat bonding, like welding or brazing, has the disadvantage of creating welding spatters, powder traces and dirt or unwanted annealing colors for corrosion resistance. In addition, subjects like heat input, thermal stress and thermal distortion have to be considered. To connect a battery tray made of resin with a battery cover, US patent application 2011143179A1 describes the use of fastening members on a flange portion.

[0012] Furthermore, as a main frame condition, for passenger cars, where the electric drive is mostly arranged in the vehicle body bottom area, the limited packaging of the battery compartment has to be considered. Using the state of the art, mostly aluminum extruded or pressed drawn profiles, the natural benefit is to have a complex form. Die cast aluminum is also used to form cast cooling channels into the structure of the battery compartment. One example of the extensive use of extruded aluminum profiles can be given by WO patent application 2018024483A1, where this type of profile, like a hollow chamber element, is used as a heat exchanger to form a temperature device inside the battery compartment. The device uses a fluid and is divided into different tempered battery cells, each case having a heat exchanger surface regarding different battery modules. Also, thus in case of a leak, the thermal system is not separated from the battery cells, and the system is intensive in terms of assembly and space.

[0013] The prior art, there are different solutions how to seal and connect different bin components to protect the internal battery cells with a closed housing. But for further functionality, especially thermal management, a simple, cost-effective system is not available. In addition, no way is provided to use flat metal sheets, which have the benefit of a cost-effective high-volume forming process for automotive mass production. Physical effects of thin metal sheets are also not used for the thermal system of the prior art. These effects can be described with the formula (1) for the heat conduction with Fourier's law, which is well known in the literature:

[0014] Q = l · A · (T1 - T2) / t (1),

[0015] where Q denotes the heat capacity [W], which for the one-dimensional case of a flat sheet is influenced by the thermal conductivity of the sheet material l [W / (m K)], the area A [mm 2 ] of the flat cross-sectional area of the sheet, the temperature difference between the warmer side T1 [K] and the cooler side T2 [K]. Finally, the heat capacity is also influenced by the sheet thickness.

[0016] It is therefore the object of the present invention to eliminate some of the disadvantages of the prior art and to achieve a supporting housing for a battery bin of an electrically driven vehicle by using flat metal sheets as at least two deep-drawn shells that are fitted into each other, whereby at least one double floor is formed, into which a passive and partially integrated thermal system for cooling and heating is integrated. As a preferred embodiment of the invention, the deep-drawn shells are manufactured with a protruding flange. The invention also relates to the integration of further functional elements, such as sensors for state measurement, which are integrated into the "double floor" and connected to the battery management system.

[0017] As a preferred embodiment of the method of the invention, the contact surfaces of one shell to the innermost shell are formed by deep-drawing, so that a defined positioning and a defined area within the double floor system are given with respect to each other. Figure 2 The contact surfaces of the shells surround the floor space of the innermost shell, in which the battery modules are located, and have the same width as the radius of the innermost shell, preferably between 5.0 mm < r < 9.0 mm. This space is tight enough on one side to achieve a high space efficiency by a large number of integrated battery modules. On the other side, with regard to the contact surfaces, there is a defined distance between the battery modules and the lateral walls of the innermost shell as a further crash safety (possible way of maximum intrusion) and a further cooling space through air.

[0018] At least two isolation valves, which work as inlet and outlet valves, are installed at the outer housing in connection with the surrounding cooling circuit elements to enable a continuous fluid flow as a closed cooling system. The flowing fluid is used and can be water, ideally with a defrosting additive, coolant or refrigerant.

[0019] As a preferred embodiment of the invention, the inlet valve is embodied as a long rod, which can be referred to as a first rod here, wherein the inlet nozzle is on the total width of the outermost housing, excluding two radii, to enable the incoming fluid to spread evenly and thus achieve an effective cooling performance. To further achieve a high cooling efficiency, the rod must be located above the resistive heating element in height. On the opposite side of the outermost housing, the outlet valve is embodied by a discharge rod, which can be referred to as a second rod here, to enable the fluid to escape. The radii of the housing, which are preferably between 5.0 mm ≤ r ≤ 8.0 mm, serve as a safety distance between the battery module and the housing, so that no actively enabled fluid flow is required in this area. To integrate the rods into the outermost housing, openings can be cut after deep-drawing the housing, for example by laser beam cutting. Thereafter, the rods can be inserted into the openings and, if necessary, can be bonded or welded from the outside with filler metal as a lap joint.

[0020] To form the heating system, different embodiments can be integrated into the double-layer floor system. A technical knit or technical fabric made of metal wire can be installed inside the formed / structured sheet and uses the physical operating principle of resistive heating. As an advantageous design, the used knit is made of a copper alloy in order to be used with good thermal conductivity, Joule's law, observation formula (2)

[0021] (Q = I 2 * R * t) (2),

[0022] where I denotes the current [A], R denotes the sum of all contact resistances and material resistances [Ω], and t denotes the time [s].

[0023] For the knit within the double-layer floor system, the typical temperature should not exceed 60 °C, more preferably not exceed 45 °C. An important design criterion for good durability of the system is to separate the knit of copper alloy from the stainless steel housing to avoid bimetallic corrosion. Bimetallic corrosion can be defined as a special form of galvanic corrosion according to DIN EN ISO 8044, or in a more colloquial expression as a contact corrosion between two metals. Without a defined separation, the cooling fluid within the thermal system would act as a conductive liquid film, a so-called electrolyte. The more noble stainless steel housing would work like a cathode, whereby the knit of copper alloy as a non-noble metal would act as an anode. In terms of the invention, the area ratio i EL is disadvantageous and enables bimetallic corrosion to occur. The area ratio can be defined with formula (3) as:

[0024] i EL = F K / F A (3),

[0025] where F K is the area of the cathode and F A is the area of the anode. Thus, in the method of the present invention, the knitted fabric of copper alloy is isolated from the stainless steel housing by a separation material, for example, by an insulating foil of plastic or polyamide, more preferably by a Teflon coating or foil.

[0026] Considering a well-balanced system with unobstructed fluid flow on one side for cooling efficiency and fast heating time of the system on the other side, the ratio r f of the height r e of the free flow area to the height r h of the resistive heating element can be defined with equation (4):

[0027] r h = r f / r e (4),

[0028] where the ratio should be r h ≥ 1.0, more preferably 1.0 ≤ r h ≤ 2.0.

[0029] In case of an up-heating, both isolation valves are closed to stop the fluid flow. Then the resistive heating starts and thus heats the stagnant fluid within the double-layered floor system. This full-area heating mechanism allows to heat all battery modules quickly and efficiently with short heating rates without the danger of overheating and necessary high energy input. For later cooling, the two isolation valves are opened again and the resistive heating is stopped, which enables a continuous fluid flow resulting in a cooling effect. If needed, also a local heating can be achieved with the method of the present invention by applying the resistive heating element only locally. Further required hardware of the complete thermal system like pumps, pressure compensation valves, further drain valves, connecting lines, fluid reservoirs like tanks or coolers like heat sinks, refrigerators or condensers can be applied from state-of-the-art solutions. For the required software like control units the same procedures can be determined. The battery cells themselves are used as power source for the thermal system.

[0030] The expected thermal management with predictive regulation is sought as a preferred embodiment of the invention to achieve high efficiency ratio and high durability of the battery cells and higher range. In this case, the control unit can be connected and linked with the navigation system to know the upcoming gradient, road type (urban traffic, plateau road or motorway) or expected range. In addition, general data such as time of the year, expected and actual external temperature and location can be queried to determine a meaningful thermal strategy with timely cooling or heating. But also during stationary situations like battery charging, the thermal system must be active to ensure loading efficiency. This is particularly necessary during fast charging which generates more heat. With the method of the invention, such a possibility comes from the hardware side without feasible constraints and is advantageous.

[0031] It is state of the art for battery electric vehicles to connect the cooling circuit of the battery with the air conditioning system by interconnection with the refrigeration circuit. With the method of the invention, it is also possible to realize this interconnection, but this is not the focus.

[0032] To achieve a temperature equalization with the desired temperature range between 15°C and 35°C with the above-mentioned method, the mechanism of heat convection between the flowing fluid directed to the battery module and the inner housing is used. Before heat transfer between the inner housing and the battery module takes place, heat conduction occurs within the sheet material, optionally through a heat transfer compound (like a thermally conductive paste) traveling in between.

[0033] As a preferred material selection, stainless steel is used to realize the method of the invention due to its corrosion resistance, heat resistance and acid resistance, generally due to its high formability, its high recyclability and its availability worldwide as a flat sheet, together with the high experience as a deep-drawing material (for example, as a kitchen sink) for decades. Thereby, the thickness of the flat metal sheet is t < 3.0 mm, more preferably t < 1.0 mm to realize a tight but lightweight and cost-effective housing construction. For the present invention, preferably for the outermost housing under the condition of being thicker than the innermost housing, a more corrosion-resistant austenitic stainless steel alloyed with chromium and nickel, optionally with molybdenum, is used. Due to this microstructure, which is associated with a significantly lower thermal conductivity relative to the ferritic microstructure, plus the case of a thicker sheet, the austenitic outermost housing works like an insulator to the outside. This makes the system more efficient and independent of the outside temperature. At the same time, the innermost housing should be executed by a ferritic stainless steel, which is thinner than the austenitic outermost housing, and has the function of a good heat conductor due to the significantly higher thermal conductivity. Thus, the at least two housings are different in their microstructure and, therefore, work like a heat conductor for the battery module and at the same time like an insulator for the surrounding area. The thermal conductivity of the innermost housing can be increased by having r λa thermal conductivity ratio of < 0.6 to create an ideal material setup. In addition, this effect can be supported by a difference in thickness of the different shells. This difference can be defined as a thickness ratio r t :

[0034] r t = r O / r i (5),

[0035] where r O is the thickness of the outermost shell in contact with the surrounding area and r i is the thickness of the innermost shell in contact with the battery module. As an ideal implementation, this ratio is r t ≥ 2.0, more preferably 2.5 < r t ≤ 3.5.

[0036] For the outermost shell, another ideal implementation of the present invention is to use a strain-hardened austenitic stainless steel, which is characterized by a yield strength R P0.2 ≥ 400 MPa, more preferably R P0.2 ≥ 800 to work like a barrier against impacts. Furthermore, a constant microstructure is sufficient to provide non-magnetic properties even in the component state to perform better electromagnetic shielding, even after forming or welding. Such grades can be characterized by a TWIP hardening effect (twin-induced plasticity) and a stacking fault energy between 20-30 mJ / m 2 .

[0037] For the inner shell, a ferritic stainless steel, in particular with titanium and / or niobium stabilized grades, can achieve the necessary deep drawability together with sufficient corrosion resistance.

[0038] To protect the system from the escape of hot fluids, the double bottom plate system must be sealed. As a preferred implementation of the present invention, the shells are deep-drawn with indentations on the protruding flanges. During deep drawing, only the punch direction can be punched, not the opposite direction. Therefore, for different shells, the indentation type must be determined differently. For the outer shell, only one indentation is required. But to form a defined counter part on the flange of the shell that is fitted into another shell, another form and number of indentations are required to form a defined sealing area at the end. Figure 6A possible combination of indentations for forming the sealing area is indicated. The sealing itself can be performed with well-known sealing compounds, such as gap fillers, adhesives (especially windshield adhesives), solid gaskets, visco-elastic silicones, hot butyl, gluing, PVC joint sealing or body cavity sealing. These sealing compounds are used as prior art in different automotive components today and can be adapted to the support housing of the present invention. In general, a cost-effective system with a fast curing process and without the need for further heat input (as required for example for single-component heat-curing adhesives) should be preferred.

[0039] Deep drawing can be performed by different stamping steps, but with as few cost-effective manufacturing processes as possible. Optionally, the trimming of the deep-drawn parts can be integrated.

[0040] One big advantage of the deep-drawn shell construction of the thermal system and the battery housing is that thermal joining processes (such as welding or brazing) can be avoided and thus the risks due to thermal distortion or contamination with welding spatters or powder traces are avoided. In addition, internal thermal stresses and also leakage problems can be avoided due to welding cracks or incomplete fusion. Therefore, a preferred joining method for the method of the present invention is a mechanical joining process on the protruding flange of the shell, such as riveting or screwing. This leads to a higher availability, a simple repair concept and reclosing. In order to follow a fast and low-step battery housing manufacturing way, a flow-drilled joining method is preferably used. In this case, the threading is performed directly by the flow-drilled screw. In addition, the protruding flange of the shell can be used for the connection with the underbody or the spacer element of the underbody and the mechanical joining element. With the present invention, it is also possible to implement the battery compartment as an interchangeable system (so-called interchangeable battery).

[0041] Various shells can also be assembled into each other. This will be of interest in the case where it is also necessary to integrate the battery management system (BMS) and its electrical components into the closed, sealed area of the battery housing. By assembling two or more shells into each other, a further protected double floor system is formed for other functionalities of the battery electric vehicle.

[0042] According to the method of applying thin flat steel sheets instead of extruded profiles, additive manufacturing or thick plates as a bending structure, thin austenitic stainless steel can also be used as a body bottom impact protection in a shaped and stacked design under the outermost shell. The result is a hollow structured area which can work like an energy absorbing element and thus protect the shell. The austenitic strain hardening grade has the potential to cold harden during deformation (like an impact) and thus works like a compression spring with a progressive characteristic line in a stacked design. At the same time, the high ductility enables a high energy absorption potential. Some examples of shaped sheets can be corrugated sheets, honeycomb structures, flexible rolled sheets, perforated sheets, bump and spherical protrusion sheets, trapezoidal sheets, arched sheets, projected sheets, edge sheets or pyramid structured sheets. As a further embodiment of the invention, crossbeams can be applied from the outside of the outermost shell to stiffen the construction in the shell floor area and further work like a load path.

[0043] In addition, the support shell ensures physical protection according to the UN R94 and R95 standards to prevent personnel from accessing the fully covered high-voltage components (IPXXB protection). In addition, no high-voltage components can be separated from the electric vehicle.

[0044] The functionality of the battery compartment of the present invention is independent of the installation location within the electric vehicle. Preferably, the battery compartment is located over the entire body bottom to ensure maximum battery range, low center of gravity and balanced driving dynamics. But partial constructions like one-sided compartments, front or rear positioning will also work. In these cases, the deep-drawn shell structure enables an adjustment to different forms or required packaging solutions.

[0045] The present invention works independently of the type of accumulator used inside (like nickel-cadmium, nickel-metal hybrid, lithium-ion or lithium-air batteries).

[0046] For the present invention, the battery management system (BMS) for charge and discharge control (load management), temperature monitoring, distance evaluation and diagnostic devices can be integrated into the battery compartment or can not be integrated into the battery compartment. The same applies to the temperature management system with its cooling fluid and cooling channels. High-voltage cables can be integrated inside the inner bottom on the inside to protect the occupants or other persons from short circuits or electrification of the vehicle or its components.

[0047] Furthermore, sensors for vibration, stress, position or movement measurement can be integrated inside the double-layer floor system as condition monitoring and collect data about the working behavior of the internal spring system.

[0048] Generally, the method of the present invention is suitable for all mobile or transport systems using battery modules. By scaling and adapting, the present invention is also suitable for other types of electric passenger or freight transport systems, like electric buses, electric commercial vehicles, electric taxis or vehicles for parcel delivery. For one vehicle, it is suitable to use one battery compartment together with the support housing of the present invention. But especially for long distance transport, like freight transport by truck as an example, various battery compartments can be integrated into the vehicle to increase the range. In this case, a support housing should be employed to implement a sufficient thermal system for each compartment with the complete surrounding hardware and in each case as an independent system with its own fluid circuit. Software and a control unit can be used to handle all compartments and thermal systems. Another reason for forming different compartments with different support housings can be the limitation of available coil and sheet width or the limitation of the maximum size of the tooling for the housing.

[0049] Further embodiments of the present invention are described below. In one embodiment, a thermal management support housing for a battery compartment of an electrically driven vehicle is provided. In this embodiment, at least two deep-drawn housings (1, 2) are fitted into each other, thereby forming at least one double floor 3, into which a passive and partially integrated thermal management system for cooling and heating is integrated to achieve a constant temperature range between 15°C and 35°C indirectly for the battery modules 5, which are separated from the thermal management system by the double floor design. Maintaining a constant temperature range between 15°C and 35°C is important for the optimal operation of the battery modules 5.

[0050] In one embodiment, at least two different flat metal sheets are used for the different housings (1, 2), which have different microstructures, thereby working like thermal conductors for the battery modules 5 and at the same time like isolators for the area surrounding the thermal management support housing by having a thermal conductivity ratio of r λ <0.6.

[0051] In one embodiment, there is a thickness ratio defining the ratio of the thickness of the outer housing and the thickness of the inner housing. The thickness ratio of the thickness of the outer housing in contact with the surrounding area and the thickness of the innermost housing 2 in contact with the battery modules 5 is r t ≥ 2.0, more preferably 2.5 ≤ r t ≤ 3.5.

[0052] In another embodiment, ferritic stainless steel is used for the innermost housing 2 in contact with the battery modules 5 and austenitic stainless steel is used for the outer housing.

[0053] In a particular embodiment, the outer housing is made of a ferritic stainless steel having a yield strength R P0.2 ≥ 400 MPa, more preferably RP0.2 The non-magnetic material with ≥ 800 MPa is made as a barrier against impacts.

[0054] In one embodiment, the heating within the innermost double floor is achieved by closing two isolation valves (e.g. 13, 14) to stop the fluid flow and by electric resistance heating with physical effect, which uses a technical knit made of copper alloy wire, which is isolated from the stainless steel housing by an isolation foil made of polyamide or plastic, more preferably Teflon.

[0055] In one embodiment, the cooling within the innermost double floor is achieved by open isolation valves (e.g. 13, 14) and a flowing liquid (such as water, coolant or refrigerant, more preferably a liquid with anti-frosting added).

[0056] In another embodiment, the support housing has a ratio (R h ) of the height of the free-flowing area to the height of the electric resistance heating element. Preferably, the ratio is r h ≥ 1.0, more preferably 1.0 ≤ r h ≤ 2.0.

[0057] In a preferred embodiment, a housing with a contact surface 8 of the innermost housing 2 surrounds the floor space in which the battery module 5 is located and has the same width as the radius of the innermost housing, preferably between 5.0 mm ≤ r ≤ 9.0 mm.

[0058] In a suitable embodiment, indentations are deep-drawn into the flange of at least one housing to create defined locations for the sealing layer.

[0059] In a particular embodiment, additional functions are integrated into the battery housing by implementing the measuring elements as double floor-like sensors for measuring ambient conditions such as temperature, deformation or system status.

[0060] In one embodiment, a hollow structured additional profiled sheet is connected to the outer housing as an additional barrier against impacts on the underbody of the vehicle.

[0061] In one embodiment, mechanical joining processes such as screw connections or mechanical joints are combined with thermal energy such as flow drilling for joining the different housings (1, 2) to each other and the locking plate 6 to the mechanical joining element 7.

[0062] In another embodiment, a two-halves housing system is used as a battery compartment for the battery module 5, whereby at least one half housing side is fitted into the other deep-drawn housing to form at least one thermal system area within the double floor 3 surrounding the battery compartment.

[0063] In one embodiment, the first rod with inlet nozzle (e.g. 19) and the second rod as discharge rod are integrated into the outermost housing 1, preferably over the total width of the housing excluding the two radii, to achieve the effective cooling concept by flowing fluid.

[0064] The application is explained in more detail with reference to the following drawings, in which

[0065] Figure 1 A preferred embodiment of the application is shown schematically by a side view.

[0066] Figure 2 Another preferred embodiment of the application is shown schematically by a side view as a cross-section of a double floor.

[0067] Figure 3 Another preferred embodiment of the application is shown schematically by a side view.

[0068] Figure 4 Another preferred embodiment of the application is shown schematically by a side view.

[0069] Figure 5 Another preferred embodiment of the application is shown schematically by a side view as a cross-section of a fluid flow.

[0070] Figure 6 Another preferred embodiment of the application is shown schematically by a side view as a cross-section of a sealing layer.

[0071] Figure 7 Another preferred embodiment of the application is shown schematically by a side view.

[0072] Figure 8 A preferred embodiment of a valve system is shown schematically by a top view (left) and a cross-sectional side view (right).

[0073] Figure 9 A typical circuit is shown as a schematic circuit diagram.

[0074] Figure 1A first deep-drawn housing (1) is shown, into which a second deep-drawn housing (2) is assembled to form a region within a double floor system (3), into which region an electric resistance heating element (4) is placed before closure. A battery module (5) is separated from the thermal management system by its location in the innermost housing (here (2)) and outside the double floor system. A locking plate (6) closes the housing (2) with the battery module (5) inside. The connection between the housings (1) and (2) and between the innermost housing (2) and the locking plate (6) is achieved by mechanical joining elements (7).

[0075] Figure 2 A preferred embodiment of the housing arrangement is shown, whereby the first housing (1) into which the inner housing (2) is assembled is designed with a support contact surface (8) so that a defined positioning relative to one another and a defined region within the double floor system is given.

[0076] Figure 3 The connection of the battery housing to the vehicle underbody (9) is shown by using a spacer element (10) which is connected to the battery housing by mechanical joining elements (7). In this figure, the arrangement is changed so that another preferred embodiment of the invention is formed, so that in a first step the double floor system (3) with the electric resistance heating element (4) is connected to the vehicle underbody. During a second assembly step, the locking plate (6) with the applied battery module (5) is connected from below to the innermost housing (2) by mechanical joining elements (7).

[0077] Figure 4 A further sheet in shaped form (11) is shown, which forms a hollow structured region (12) and is connected to the outermost housing (1) as a further barrier layer against impacts on the vehicle underbody.

[0078] Figure 5 A cross-sectional view of the thermal management system is shown. During cooling, both isolation valves, called inlet valve (13) and outlet valve (14), are opened and enable cooling with a continuous fluid flow. If heating is required, both isolation valves are closed and the electric resistance heating element (4) is activated and thus heats the stagnant fluid within the double floor system (3).

[0079] Figure 6A sealing layer (15) of a first deep-drawn housing (1) and a second deep-drawn housing (2) is shown in a cross-sectional view, which is fitted into the first deep-drawn housing (1). In order to seal off the inner double floor system (3) from the outside environment and to avoid any type of contamination (such as dust, dirt, other particles or moisture) from the outside, but also to avoid liquid discharge from the double floor system, a sealing layer is covered into the deep-drawn indentations (16) at the housing flanges. The mechanical joining elements (7) have to be arranged outside the indentations (16) and the sealing layer (15).

[0080] Figure 7 Another preferred embodiment of the invention is shown, which uses another deep-drawn housing (17) instead of the locking plate (6) to form a two half housing system for a battery module. In an advantageous manner, the additional deep-drawn housing (17) is identical to the innermost housing (2), so that only one deep-drawn tool is required for both housings. At least one half housing side is fitted into the first deep-drawn housing (1) to form a thermal system area within the double floor system (3). Also here, mechanical joining elements (7) can be used to connect the housings.

[0081] Figure 8 A preferred embodiment of the valve system is shown, whereby a rod (18) with an inlet nozzle (19) is integrated as an inlet valve (from Figure 4 13) to enable the fluid to enter. On the opposite side of the outermost housing, a second rod (20) as an outlet valve (from Figure 4 14) is integrated as a discharge element for the fluid. As a preferred embodiment of the fluid flow, both rods are located on the total width of the housing, except for two radii (21). Thus, as can be seen from the cross-sectional side view on the right side, Figure 8 the rods are located above the resistive heating element (4) in height.

[0082] Figure 9 A typical circuit is shown as a schematic circuit diagram with different components and possible interconnections. The order and use of the individual components can vary.

Claims

1. A thermal management support housing for a battery compartment of an electric vehicle, comprising at least two housings assembled into one another to form at least one double floor, wherein a thermal management system for cooling and heating is integrated into the double floor to indirectly achieve a constant temperature range of between 15°C and 35°C for the battery modules, wherein the thermal management system is passive and partially integrated, and the battery modules are separated from the thermal management system by the design of the double floor. It is characterized by: The two shells are deep drawn, and ferritic stainless steel is used for the innermost shell in contact with the battery module and austenitic stainless steel is used for the outer underbody skin, and The thickness ratio of the outer shell in contact with the surrounding area and the innermost shell in contact with the battery module is r t ≥2.

0.

2. The thermal management support housing according to claim 1, wherein: 2.5≤r t ≤3.5。 3. The thermal management support housing according to claim 1, wherein: At least two different flat metal sheets are used for different housings, with different microstructures, so that by having r λ A thermal conductivity ratio of ≤0.6 acts as a heat conductor for the battery module and simultaneously as an insulator for the surrounding area.

4. The thermal management support housing according to any one of claims 1 to 3, characterized in that: The outer shell has a yield strength R P0.2 Made of non-magnetic material with a strength of ≥400MPa, it serves as a barrier layer against impact.

5. The thermal management support housing according to claim 4, wherein: R P0.2 ≥800MPa。 6. The thermal management support housing according to claim 1, wherein: Heating within the innermost double bottom plate is achieved by closing two isolation valves to stop the fluid flow and by resistive heating with a physical effect, which uses a technical knit made of copper alloy wires, which is isolated from the stainless steel shell by an isolation foil made of polyamide or plastic.

7. The thermal management support housing according to claim 6, wherein: The separator foil is made of Teflon.

8. The thermal management support housing according to claim 1, wherein: Cooling within the innermost double bottom plate is achieved by open isolation valves and flowing liquid.

9. The thermal management support housing according to claim 8, wherein: The flowing liquid includes water, coolant, refrigerant, and liquid with anti-frost added.

10. The thermal management support enclosure of claim 1 , having a ratio of the height of the free flow area to the height of the resistive heating element (r h ), characterized in that The ratio r h ≥1.

0.

11. The thermal management support enclosure according to claim 10, wherein: 1.0≤r h ≤2.0。 12. The thermal management support enclosure according to claim 1, wherein: A contact surface of one case with the innermost case surrounds a floor space where the battery module is located and has the same width as a radius of the innermost case.

13. The thermal management support enclosure according to claim 12, wherein: The width is 5.0 mm ≤ r ≤ 9.0 mm.

14. The thermal management support enclosure according to claim 1, wherein: Indentations are deep-drawn into the flange of at least one housing to form defined locations for the sealing layer.

15. The thermal management support enclosure according to claim 1, wherein: Further functions are integrated into the battery housing by implementing the measuring element as a double-bottomed plate-like sensor for measuring ambient conditions, including temperature, deformation or system status.

16. The thermal management support enclosure according to claim 1, wherein: A further profiled sheet of hollow structure is connected to the outer shell as an additional barrier against underbody impacts.

17. The thermal management support enclosure of claim 1, wherein: A mechanical bonding process or a combination of mechanical bonding and thermal energy is used to bond the different housings to each other and to bond the locking plate to the mechanical bonding element.

18. The thermal management support enclosure of claim 1, wherein: A two-shell system is used as a battery compartment for the battery module, whereby at least one half-shell side is assembled into another deep-drawn shell to form at least one thermal system region within a double floor system surrounding the battery compartment.

19. The thermal management support enclosure of claim 1, wherein: A first rod having an inlet nozzle and a second rod serving as a discharge rod are integrated into the outermost housing to achieve effective cooling performance using flowing fluid.

20. The thermal management support enclosure of claim 19, wherein: The first rod and the second rod are integrated over the total width of the housing excluding two radii.

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