Housing with battery cells for forming at least part of a traction battery for an electrically driven motor vehicle

Abstract

Housing (10) with battery cells (11), for forming at least part of a traction battery (T) for an electrically driven motor vehicle (K), wherein at least one maintenance opening (15) can be opened on the housing (10), which serves for the maintenance and / or replacement of a component located in the housing (10), wherein the maintenance opening (15) provides access to a maintenance shaft (17) through which a receiving space for at least one battery cell management control device (13) is formed, wherein the maintenance shaft (17) is separated from a receiving space (18) for the battery cells (11), characterized in that the housing (10) has a longitudinal extension (11) and a quadrangular cross-section, with two side walls (101), an upper and a lower wall (104 and 103), wherein the maintenance shaft (17) is formed within a maintenance box (12) of quadrangular outline, from which end walls (121) the side walls (101) of the housing (10),an upper wall (120) touches the upper wall (104) of the housing (10) and a lower wall (122) touches the lower wall (103) of the housing (10).,

Description

The invention relates to a housing with battery cells for forming at least part of a traction battery for an electrically drivable motor vehicle, having the features of the preamble of claim 1.A housing is known from DE 10 2014 217 982 A1. The housing has a lower shell made of metal, which is hermetically screwed to a cover made of plastic. A service screen is located in the top of the cover to enable access to the interior of the housing. In this way, serviceable parts can be serviced or replaced. The serviceable parts may include, for example, a controller, a battery cell, or any other component of a battery assembly. Specifically, the maintenance panel is formed by a tear strip which can be torn open by means of a tab and can thus expose a maintenance opening. After maintenance work has been carried out, the maintenance screen can be sealed off again by a replacement screen.DE 10 2009 043 635 A1 describes a battery housing which has service flaps on a cover and on an outer wall for access to an interior of the battery housing. For greater maintenance work, the lid and the bottom of the battery housing are removable.Finally, EP 1 132 251 A1 describes a hybrid drive system having a battery unit, a fuel unit and an engine. In order to achieve easy assembly or maintenance and high reliability of the system, it is proposed to provide the engine, the battery and the fuel system as modular units. Each unit is provided with a control and monitoring device in order to control and monitor the state of the respective module.Housings with battery cells of the generic type are known in each case from DE 10 2016 214 255 A1, DE 10 2016 103 906 A1, US 2009 / 0 017 368 A1, DE 10 2015 119 156 A1, DE 10 2009 009 701 A1, DE 10 2009 009 700 A1 and post-published DE 10 2017 130 054 A1.From DE 10 2016 115 647 B3 and DE 10 2016 217 935 A1, an electrically drivable motor vehicle with a traction battery is known, in each case, the traction battery being constructed from individual battery modules. The housings of the battery modules are detachably connected to the motor vehicle.The known prior art has the disadvantage that during maintenance work the housing has to be opened in such a way that the battery cells located in the battery housing are at least partially exposed. However, this is not harmless in the case of the voltages in the high-voltage range that are customary in traction batteries, so that high precautions are required during disassembly and maintenance work. Moreover, the exposure of the battery cells during maintenance work can also lead to damage to the battery cells.The object of the present invention is therefore to provide a housing with battery cells according to the features of the preamble of claim 1, in which a battery cell management control device assigned to the battery cells can be easily managed. In particular, maintenance or replacement should be possible without risk, wherein the risk of damage to the battery cells is to be minimized.The present object is achieved with a housing having the features of claim 1.The present invention is also based on the object of providing an electrically drivable motor vehicle which meets the requirements for easy and safe serviceability. This object is achieved by an electrically drivable motor vehicle having the features of patent claim 6.Advantageous embodiments or refinements of the invention can be gathered from the respective dependent claims.The invention therefore initially proceeds from a housing with battery cells for forming at least a part of a traction battery for an electrically drivable motor vehicle. At least one maintenance opening can be exposed on the housing, which serves for the maintenance and / or for the replacement of a component located in the housing. Examples of suitable electrically drivable motor vehicles are hybrid vehicles (HEV=hybrid electric vehicles), plug-in hybrid vehicles (PHEV=plug-in hybrid electric vehicles) or else pure electric vehicles, that is to say battery vehicles (BEV=baery electric vehicles).The invention now proposes that the maintenance opening enables access to a maintenance compartment, by means of which a receiving space for at least one battery cell management control device is formed. The maintenance shaft is separated from a receiving space for the battery cells. The maintenance shaft thus forms a self-contained accommodation space for the battery cell management control device.In this way, easy and safe maintenance or easy replacement of the battery cell management control device is possible. By separating the receiving space of the battery cell management control device from the receiving space for the battery cells, the receiving space for the battery cells therefore does not have to be exposed in the case of maintenance. In this way, the risk of damage to the battery cells is avoided and maintenance is possible without risk.The housing has a longitudinal extension and a square, preferably rectangular, cross section. The housing has two side walls, an upper and a lower wall. The maintenance shaft is formed within a maintenance box which is square in contour, preferably rectangular. Of this service box, end walls contact the side walls of a housing, an upper wall contacts the upper wall of the housing, and a lower wall contacts the lower wall of the housing.Thus, the maintenance box with the maintenance shaft can simultaneously support the structure of the housing. The maintenance box is therefore a component of the housing structure. In this way, in the region of the maintenance box, stiffening of the structure of the housing takes place. The housing can thus absorb forces in the X direction (longitudinal direction) and / or Z direction (vertical direction) in the region of the maintenance box with a corresponding installation position transversely to a longitudinal extent of the motor vehicle.In one embodiment, the maintenance box is arranged in the middle of a longitudinal extent of the housing. In this way, the preconditions are created for the fact that, in the case of a traction battery formed from a plurality of housings, a central load path acting in the longitudinal direction of the motor vehicle can be generated.In order to be able to absorb forces in the longitudinal direction of the housing and thus in the assembled state in the Y direction (transverse direction) of the motor vehicle, the housing is made of metal, preferably of light metal such as aluminum. At least the side walls, the upper and the lower wall of the housing each have a wall thickness of about 4 to 6 millimeters, preferably of about 5 millimeters.As is known, battery cell management control devices (so-called CMCs=cell management controllers) are used to monitor the state of the battery cells of an associated cell stack. Each battery cell management control device thus has to take care that the battery cells assigned to it "feel well" and the battery cell stack assigned to it is operating properly. Each battery cell management control device must in turn be connected by signal technology to a higher-order battery management control device. The battery management controller then coordinates the battery management controllers for the "need" of the traction battery formed by the housings. This generally necessitates complex cabling among the said control devices.According to a very advantageous embodiment of the inventive concept, it is therefore proposed that means are provided for wirelessly communicating the battery cell management control device with other battery cell management control devices and / or with a higher-order battery management control device.This allows an even simpler, almost closed design of the housing.The means for wireless communication can expediently be designed to be optical, radio or inductive. Optical means which may be used are, for example, light guides connected to phototransistors. As radio-technology designs, for example, near-field radio networks are conceivable.As mentioned initially, the invention is also intended to protect an electrically drivable motor vehicle. According to the invention, the electrically drivable motor vehicle has a plurality of housings according to the invention, wherein the housings form a traction battery of the motor vehicle. Each of the housings is detachably connected to the motor vehicle.The individual housings thus form quasi individual battery modules, wherein tappable individual voltages of the individual housings are interconnected to form a tappable total voltage of the traction battery.Such a modular construction offers the enormous advantage that, in the event of damage or malfunctions of individual battery cells, it is not necessary as usual to remove the entire traction battery with a housing, but rather only the battery module concerned Furthermore, this leads to a clearly easier handlability in the event of a necessary replacement. It is thus conceivable, for example, to equip each battery module with a touch voltage of significantly below 100 volts, preferably below 60 volts. Maintenance work on such a battery module is therefore substantially more uncomplicated in terms of voltage than maintenance work on a conventional traction battery with a contact voltage of several hundred volts. The same applies to the individual weight of the battery modules, which is many times lower than the total weight of previously customary traction batteries.An embodiment of the motor vehicle proposes that the maintenance openings of the housings point downward, i.e. in the direction of a roadway. As a result, the serviceability, in particular of the battery cell management control devices on the motor vehicle, can be optimized.According to another development of the proposed motor vehicle, the housings are oriented with their longitudinal extent transversely, in particular at right angles to a longitudinal extent of the motor vehicle. The housings touch each other with their mutually facing side walls. In this way, a mutual support and thus a load path in the X direction (longitudinal direction) of the motor vehicle is made possible.According to a further embodiment of the inventive concept, it is further proposed that a receiving space for receiving the housings is held in the region of longitudinal members of the motor vehicle, wherein exactly one housing can be received or is received between two longitudinal members as viewed in the transverse direction of the motor vehicle. Viewed in the longitudinal direction of the motor vehicle, exactly an integral multiple of the housings can be stacked or stacked on one another.By means of such a development, optimum use of space of the space available can be achieved.Due to different customer requirements, it is conceivable that some customers do not wish to have made available the theoretically maximum possible range of the electrically drivable motor vehicle. To adapt to different customer requirements, it is therefore very advantageous if, in addition to at least one housing according to the invention, at least one empty housing is inserted in the stack. The empty housing therefore has neither battery cells nor control devices.In this way, the range of the traction battery of the electrically drivable motor vehicle can be adapted as required, wherein at the same time the load path in the X direction can be maintained for a possible crash situation.In order to enable good cooling of the traction battery and nevertheless not to make it difficult to exchange the housings and / or the battery cell management control devices, it is furthermore proposed that the housings are connected to refrigerant-carrying cooling ducts in a heat-conducting manner on the side of their upper wall. As the refrigerant, CO 2 may be used, for example.In order to reduce the dimensions in the Z direction (vehicle vertical direction), the housings or the traction battery is additionally covered on their underside by an underride guard made of fiber composite plastic.Preferred exemplary embodiments of the invention are illustrated in the figures and are explained in more detail in the following description with reference to the figures. This also makes further advantages of the invention clear. Identical reference numerals, also in different figures, relate to identical, comparable or functionally identical components. Corresponding or comparable properties and advantages are achieved in this case, even if a repeated description or reference thereto is not made. The figures are not, or at least not always, true to scale. In some figures, proportions or distances may be exaggerated to more clearly emphasize features of an embodiment.They show, in each case schematically FIG. 1 is a top view of a housing having battery cells and battery cell management controllers, FIG. 2 shows a view of the housing from the bottom side, FIG. 3 is a perspective view of the housing, FIG. 4 shows a representation of the housing according to sectional view IV from FIG. 3, FIG. 5 shows an electrically drivable motor vehicle with a plurality of mounted housings, partially as an exploded illustration, and FIG. 6 is another exploded view of the motor vehicle.FIG. 1 shows a housing 10 in which a plurality of battery cells 11 are accommodated. The housing 10 is of rectangular cuboid configuration and, in the view shown from above, has a rectangular contour with side walls 101 and end walls 102. The housing 10 has a longitudinal extent l1 and a width b. As can be seen, the longitudinal extent l1 of the housing is many times greater than its width b.Approximately in the middle of the longitudinal extension l 1, a maintenance box 12 is arranged in a central plane ME.Viewed in the longitudinal direction l 1, a receiving space 18 for the battery cells 11 is formed in the housing 10 on both sides of the maintenance box 12. The battery cells 11 in each receiving space 18 are oriented with their longitudinal extent parallel to the longitudinal extent l 1 of the housing 10 and fill the receiving space 18 substantially in each case. Necessary insulating measures for insulating the battery cells 11 from the walls of the housing 10 are not shown.The housing 10 is substantially closed and is thus formed to be water-tight. The battery cells 11 accommodated in the housing 10 and the maintenance box 12 are indicated by dashed lines for the sake of clarity.Furthermore, high-voltage (HV) plug terminals 14 are illustrated. These HV plug terminals 14 can be connected by means of suitable plug connectors (not shown) and thus connected to further housings 10 by voltage technology to form a larger unit.Each of the HV plug terminals 14 is sealed separately and has a contact protection (not shown in more detail).The maintenance box 12 serves in particular for receiving two battery cell management control devices 13, which can be plugged into suitable plug connections (not shown) within the maintenance box 12. Each of the battery cell management controllers 13 is responsible for managing a cell stack 11' associated therewith.Reference numeral 19 denotes a wireless communication interface which is used for communicating or exchanging data between the battery cell management control devices 13 and other battery cell management control devices 13 of other housings 10 or with a superordinate battery management control device (not illustrated). The communication interface 19 can be designed, for example, optically, wirelessly or also inductively.FIG. 2 shows the housing 10 from a lower wall 103. The battery cells 11 are no longer shown.The maintenance box 12 forms two maintenance shafts 17, each of which can be accessed via a maintenance opening 15 from the lower wall 103.Each maintenance opening 15 can be closed by a releasable cover 16, only one of which is shown. Each cover 16 seals off the maintenance shaft 17 in a sealing manner and is preferably connected to the lower wall 103 by a screw connection. In this way, the housing 10 is formed as a whole in a water-tight manner.When a battery cell management control device 13 is required to be serviced, it is merely necessary to remove the cover 16, as a result of which access to the maintenance compartment 17 and thus to the battery cell management control device 13 is enabled. This can then be simply pulled out of the maintenance shaft 17 and optionally replaced by a new one.As an alternative to the exemplary embodiment, it is also conceivable for the maintenance shafts 17 to be closed by covers which are a fixed component of the lower wall 103. However, these are then surrounded by predetermined breaking points and can be broken out during maintenance. After maintenance has taken place, the openings 15 can be closed again in a sealed manner by a suitable cover which is then screwed, for example, to the wall 103 (not shown).In FIG. 3, the housing 10 is shown in perspective. In the installed state of the housing 10, X represents a vehicle front-rear direction, Y represents a vehicle width direction, and Z represents a vehicle height direction.In this illustration, one of the side walls 101, one of the end walls 102 and also an upper wall 104 of the housing 10 are easily visible.The maintenance box 12 arranged in the middle of the housing 10 and a battery cell management control device 13 (only one of two is shown) accommodated therein are shown in dashed lines. The cell stacks 11' accommodated in the housing 10 are likewise indicated.The side walls 101, the upper wall 104 and also the lower wall 103 have a wall thickness d (compare also FIG. 4 ) which is approximately 4 to 6 millimeters, preferably approximately 5 millimeters. In this way, forces Fyin the vehicle transverse direction can be absorbed well by these walls.It is clear from FIG. 4 that the maintenance box 12 has a rectangular, in particular rectangular, shape in its outline. In this case, it fills the similarly rectangular cross section of the housing 10 from the inside and bears with an upper wall 120 against the upper wall 104 of the housing 10, with a lower wall 122 against the lower wall 103 of the housing 10 and with end walls 121 against the side walls 101 of the housing 10. The maintenance box 12 is preferably held firmly in the housing 10 via an adhesive connection or via a press fit. In the figure, for the sake of better illustration only, a small distance is left between the maintenance box 12 and the walls of the housing 10.Due to the mutually contacting wall thicknesses of the housing 10 on the one hand and the wall thicknesses of the maintenance box 12 on the other hand, a particularly high stability arises in the region of the maintenance box 12, which enables a transmission of high forces Fx in the vehicle longitudinal direction and / or of forces Fz in the vehicle vertical direction.FIG. 5 shows an electrically drivable motor vehicle K (only body shell), which has a longitudinal extent l2. In particular, a receiving space A formed between longitudinal members 20 (sills) is formed in such a way that exactly one housing 10 fits between the longitudinal members 20 in a vehicle transverse direction and the receiving space A can receive exactly six housings 10 in the longitudinal extension l 2 of the motor vehicle K.The figure is partially shown in exploded view. Thus, in addition to five housings 10, an empty housing 10' is shown exposed, in which neither battery cells 11 nor battery cell management control devices 13 are located. As a result, the range of the motor vehicle K can be adapted to a customer's wish, if necessary. For this purpose, the empty housing 10' has exactly the same dimensions as the housings 10. Therefore, it is also conceivable to replace further ones of the housings 10 by an empty housing 10' or to integrate no empty housing 10' at all. Furthermore, a connector strip 21 is shown exposed as a central connection element, which enables the total voltage interconnected by the individual housings 10 to be tapped off and supplies a non-illustrated electric motor with voltage.It can also be seen that all the maintenance openings 15 or covers 16 are accessible from the underside of the motor vehicle K.After removal of an underrun protection 22, either individual battery cell management control devices 13 can thus be removed and replaced in a targeted manner or selected housings 10 and 10'can easily be removed. Each of the housings 10 or 10' can be screwed to the longitudinal beams 20 via recesses 28 of connecting flanges 29 present on the end face (compare FIG. 3 ).Finally, FIG. 6 shows a somewhat different exploded view of the motor vehicle K, wherein cooling channels 23 arranged above the housings 10 are visible. In the final assembled state of the motor vehicle K, the cooling channels 23 are in a thermally conductive connection with the upper wall 104 of the housings 10. The housings 10, each of which constitutes a battery module, form a traction battery T of the motor vehicle K.The modular construction described greatly facilitates flexibility and handling during maintenance. In addition, the battery cell management control devices 13 assigned to each housing 10 and easily replaceable make very simple maintenance possible.Furthermore, in this way, the use of a housing 10 as a full-value voltage source with its own energy management can also take place in technical fields other than automotive engineering, for example as a stand-alone solution.Reference numeral 24 designates a sill reinforcement made of fiber composite plastic. This leads to additional safety against lateral crash loads acting on the traction battery T.Plug contacts 25 are shown, which can be inserted into the HV plug terminals 14 (cf. FIG. 3 ) and by means of which the individual voltages of each housing 10 can thus be tapped and finally combined with the aid of the already mentioned plug strip 21. The plug contacts 25 can be connected to one another via a connecting strip 26.Finally, further supply lines 27 are shown, which are likewise routed along the top side of the traction battery T or of the housings 10 and the position of which therefore also contributes to easy serviceability of the traction battery T.LIST OF REFERENCE CHARACTERS10 Housing 10' Empty housing 11 Battery cells 11' Cell stack 12 Maintenance box 13 Battery cell management control devices 14 HV plug terminals (sealed) 15 Maintenance opening 16 Cover 17 Maintenance shaft 18 Receiving space 19 Wireless communication interface, Wireless communication means 20 longitudinal member 21 plug strip 22 underride protection 23 cooling channels 24 sill reinforcement made of fiber composite plastic 25 plug contacts 26 connecting strip 27 supply lines 28 recesses 29 connecting flange 101 side walls 102 end walls 103 lower wall 104 upper wall 120 upper wall 121 end walls 122 lower wall A receiving space b width d wall thickness Fx force Fy force Fz force K electrically drivable motor vehicle l 1 longitudinal extension of the housing l 2 longitudinal extension of the motor vehicle ME median plane T traction battery X vehicle longitudinal direction Y vehicle transverse direction Z vehicle vertical direction

Claims

Housing (10) with battery cells (11), for forming at least part of a traction battery (T) for an electrically drivable motor vehicle (K), wherein at least one maintenance opening (15) can be opened on the housing (10), said maintenance opening serving for the maintenance and / or for the replacement of a component located in the housing (10), wherein the maintenance opening (15) enables access to a maintenance shaft (17), by means of which a receiving space for at least one battery cell management control device (13) is formed, wherein the maintenance shaft (17) is separated from a receiving space (18) for the battery cells (11), characterized in that the housing (10) has a longitudinal extent (l1) and a square cross section, having two side walls (101), an upper and a lower wall (104 and 103), wherein the maintenance shaft (17) is formed within a maintenance box (12) which is square in outline, of which end walls (121) contact the side walls (101) of the housing (10), an upper wall (120) contact the upper wall (104) of the housing (10) and a lower wall (122) contact the lower wall (103) of the housing (10).Housing (10) according to Claim 1, characterized in that the maintenance box (12) is arranged in the middle of the longitudinal extent (l1) of the housing (10).Housing (10) according to one of the preceding claims, characterized in that it is made of metal and at least the side walls, the upper and the lower walls (101, 104 and 103) of the housing (10) each have a wall thickness (d) of between 4-6 mm.Housing (10) according to one of the preceding claims, characterized in that means (19) for wireless communication of the battery cell management control device (13) with other battery cell management control devices (13) and / or with a higher-order battery management control device are present.Housing (10) according to Claim 4, characterized in that the means (19) for wireless communication of the battery cell management control device (13) are designed to be optical, radio or inductive.Electrically drivable motor vehicle (K), characterized byseveral housings (10) according to one of Claims 1 to 5, wherein the housings (10) form a traction battery (T) and each of the housings (10) is detachably connected to the motor vehicle (K).Electrically drivable motor vehicle (K) according to Claim 6, characterized in that the maintenance openings (15) of the housings (10) point downwards.Electrically drivable motor vehicle (K) according to Claim 6 or 7, characterized in that the housings (10) are oriented with their longitudinal extent (l1) transversely with respect to a longitudinal extent (l2) of the motor vehicle (K) and the housings (10) touch one another with their mutually facing side walls (101).Electrically drivable motor vehicle (K) according to Claim 8, characterized in that a receiving space (A) for receiving the housings (10) is held in the region of longitudinal members (20) of the motor vehicle (K), wherein, as seen in the transverse direction of the motor vehicle (K), exactly one housing (10) can be received or is received between two longitudinal members (20) and, as seen in the longitudinal direction (l2) of the motor vehicle (K), exactly an integer multiple of the housings (10) can be stacked or is stacked on one another.Electrically drivable motor vehicle (K) according to Claim 9, characterized in that, in addition to at least one housing (10), at least one empty housing (10') is inserted in the stack.Electrically drivable motor vehicle (K) according to one of Claims 6 to 10, characterized in that the housings (10) are connected on the side of their upper wall (104) in a heat-conducting manner to cooling ducts (23) which carry refrigerant.Electrically drivable motor vehicle (K) according to one of Claims 6 to 11, characterized in that the housings (10) are covered on their underside by an underride guard (22) made of fibre composite plastic.

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