Battery with immersion cooling, and method for cooling a battery

Abstract

A battery (1) having a plurality of electrochemical cells (2) is temperature-controlled by immersion cooling. The battery (1) comprises a battery housing (3) having a basic prismatic shape, each of the individual electrochemical cells (2) also being prismatically shaped; flat distributors (4, 5, 6, 7) for supplying and discharging immersion fluid on opposite sides of the battery housing (3); and meandering flow channels (12) which connect the flat distributors (4, 5, 6, 7) to one another and are formed between electrochemical cells (2) and into which rigid spacing and flow-guiding elements (15) are inserted. Component groups formed by a plurality of cells (2) mechanically connected one behind the other and by spacing and flow-guiding elements (15) are loaded, in each case, by the force of a respective pre-tensioning element (16).

Description

[0001] Battery with immersion cooling and method for cooling a battery

[0002] The invention relates to a battery comprising a plurality of electrochemical cells, in particular a secondary battery, with immersion cooling. Furthermore, the invention relates to a method for cooling a battery comprising a plurality of electrochemical cells.

[0003] Immersion cooling refers to a cooling process in which an object or assembly to be cooled, such as a battery cell and / or an electronic component, is directly surrounded by an electrically non-conductive dielectric fluid, i.e., immersed in the fluid. Depending on the requirements, the circulating immersion fluid can also be used to heat the object or assembly.

[0004] A battery that is temperature-controlled by immersion cooling is known, for example, from US Pat. No. 11,626,636 B2. One assembly of the known battery includes a compressible spacer assembly, i.e., a spacer arrangement. The battery according to US Pat. No. 11,626,636 B2 is designed for use in electric vehicles. This assembly is enclosed by an outer shell assembly. The use of a non-flammable dielectric as the immersion fluid is recommended.

[0005] Another temperature control device for individual battery cells assembled into a module is disclosed in US 11,677,107 B2. In this case, the battery cells have a cylindrical shape. The device according to US 11,677,107 B2 comprises sealing elements formed as two identical molded parts that are aligned point-symmetrically to each other.

[0006] WO 2022 / 022759 A1 discloses a heat exchanger arrangement for batteries used in electric vehicles. A heat transfer medium flows through an inner circuit of the arrangement according to WO 2022 / 022759 A1. A volume filled with heat transfer medium, which is assigned to the inner circuit, is delimited, among other things, by parallel surfaces and a molded seal.

[0007] An energy storage device described in US 2013 / 0017428 A1 comprises numerous batteries arranged in a row-column configuration. Air flowing through the energy storage device flows through various interconnected ducts, some of which are aligned orthogonally to each other.

[0008] DE 10 2020 120 746 A1 relates to a module for a high-voltage storage system with immersion cooling. The module comprises several battery cells arranged in a common housing and can, for example, be prismatically shaped or designed as pouch cells. Reversibly deformable spacer elements are arranged between the side surfaces of the battery cells. A coolant, whose thermal conductivity is specified as 0.1 W / m K to 15 W / m K, comes into direct contact with these side surfaces.

[0009] DE 10 2014 223 178 A1 deals with a contact pressure concept for a cooling device of a high-voltage storage system. According to this concept, a spring element is used to press a cooling device flat against an energy storage module of a high-voltage storage system. The spring element forms at least two elastic spring legs to generate a contact pressure. The device according to DE 10 2014 223 178 A1 is intended to be particularly suitable for use in a hybrid or electric vehicle.

[0010] DE 10 2021 210 265 A1 describes a fluid management module for cooling an electrical energy storage device using immersion cooling. A valve unit is arranged between an inlet connection and an outlet connection of the fluid management module, ensuring that fluid flows exclusively in the intended direction through a fluid path. Several cooling paths are routed through a housing of the fluid management module. DE 10 2022 127 418 A1 relates to systems for active thermal management with multipurpose containers for battery assemblies cooled by immersion in liquid. For example, a cuboid-shaped arrangement of battery modules can be supplied with coolant from one side of the cuboid arrangement. The coolant is discharged via the opposite side of the cuboid arrangement.

[0011] The invention is based on the object of providing a battery operating with immersion cooling that is further developed compared to the cited prior art and is characterized by a compact, production-friendly design while simultaneously achieving high achievable cooling performance. Furthermore, an advanced immersion cooling method is to be provided.

[0012] This object is achieved according to the invention by a battery, in particular a secondary battery, having the features of claim 1. The object is also achieved by a method designed according to claim 20 for cooling a battery comprising several electrochemical cells. Where reference is made to "cooling" in this text, the corresponding statements also apply to heating, i.e., generally, to temperature control. The explanations related to the cooling or heating method also apply mutatis mutandis to the device, i.e., the battery, in particular in the form of a secondary battery, and vice versa.

[0013] The battery according to the application, which has a plurality of electrochemical cells and provides for temperature control of the individual cells by immersion cooling, comprises

[0014] - a battery housing with a prismatic basic shape, whereby the individual electrochemical cells are also each prismatically shaped,

[0015] - a plurality of flat distributors for the supply and discharge of immersion fluid on different sides of the battery housing, - meandering flow channels formed between electrochemical cells which connect the flat distributors to one another and into which rigid, i.e. elastically not yielding to a technically relevant extent, spacer and flow guide elements are inserted, wherein component groups which are formed from a plurality of mechanically connected cells and spacer and flow guide elements are each loaded by the force of at least one prestressing element, in particular in the form of a metallic or non-metallic spring element.

[0016] As for the aforementioned flat distributors, there are at least two pairs of distributors. Each of these distributor pairs consists of two flat distributors connected in series for the supply or discharge of immersion fluid, so that in total there are at least four flat distributors. The distributors belonging to one and the same distributor pair are arranged on two adjacent sides of the battery housing, each forming a finite angle (i.e., angle other than zero). Each distributor belonging to a first distributor pair is opposite a distributor belonging to another distributor pair.

[0017] The invention is based on the idea that immersion cooling is fundamentally a highly efficient cooling method. When cooling electrochemical cells, it must be considered that the cells are subject to dimensional changes over the lifespan of the battery constructed from them, particularly due to charging and discharging processes. To accommodate such geometric changes in the cells, older approaches offer flexible spacers that also serve a flow-guiding function.

[0018] The solution according to the application deliberately departs from such approaches by separating the flow-guiding function performed by the spacer and flow-guiding elements from the geometric balancing function performed by the at least one spring element positioned in a row with the consecutively arranged cells. This enables the spacer and flow-guiding elements to remain permanently in flat contact with the cells over the entire service life of the battery.

[0019] The spacer and flow-guiding elements, which are not elastically flexible to a technically relevant extent and are generally also referred to as intermediate elements, are located in various embodiments on the largest surfaces of the cuboid-shaped cells of the battery. Of the respective surfaces, which have a square or other rectangular shape, for example, the spacer and flow-guiding element covers a partial area corresponding, for example, to less than half, in particular less than a quarter, of the aforementioned cell surface.

[0020] In this way, the cells, geometrically arranged in a row, are almost completely immersed in immersion fluid. This applies regardless of the electrical connection of the cells, i.e., the conventional parallel connections and / or series connections. The flow of the fluid, i.e., the flow of electrically non-conductive immersion fluid, is guided close to the cell walls, which can result in high flow velocities and highly pronounced turbulence. This promotes high heat dissipation and at least approximately uniform operating conditions for the cells throughout the battery housing.

[0021] The areas surrounded by the immersion fluid are not necessarily separated from other areas within the battery housing by seals. Even without such hermetic seals, flow-guiding structures can be formed within the battery housing or directly through the battery housing, in addition to the spacer and flow-guiding elements, which are inserted as rigid spacers between the individual electrochemical cells. These structures ensure a targeted distribution of the fluid flow.

[0022] For example, such flow-guiding structures are present as a perforated plate in at least one distributor for supplying or discharging immersion fluid to or from the cells. The individual openings in the perforated plate can have a cell-specific diameter. Furthermore, it is possible to separate the flow spaces on the cell side of the perforated plate from cell to cell by bringing the intermediate elements, i.e., spacer and flow-guiding elements, up to the perforated plate. This prevents any pressure differences that may exist between subvolumes bordering different cells from leading to undesirable compensating flows, which would result in uneven cooling of the cells.

[0023] The complete flow paths, fluidically connected in parallel, through which the immersion fluid can flow through the battery, can be designed such that all paths are at least approximately the same length. Embodiments can also be realized in which different flow paths have different lengths. This is possible, for example, when components in the battery housing, including the electrochemical cells arranged in a matrix, differ from one another in terms of their heat generation.

[0024] The battery housing either encloses a single interior space containing all electrochemical cells, or is modularly divided into several subspaces, each for a plurality of cells arranged in a matrix. Conversely, the battery housing, including its internal components and the cells, can represent only one module of a larger assembly of an electrochemical system, particularly a battery system. This allows for various design options for a "cell-to-pack" design. Various components of a hierarchically structured control system can be located inside or outside the battery housing.

[0025] Regardless of the number and arrangement of the components inside and / or outside the battery housing that are intended to operate the battery system, in addition to the cells, each spring element that holds a row of cells under mechanical preload has the task of compensating for tolerances in exactly one dimension. In a direction orthogonal to this, the battery cells can also be arranged in rows, with the cells lined up with their narrow sides in this direction. With regard to the flow of the immersion fluid, the narrow sides of the cells are of secondary importance.Between the narrow sides, i.e. the small side surfaces of the cells, a gap can exist which forms a flow channel which is parallel to the channels formed by the spacer and flow guide elements and also contributes to the heat exchange, whereby due to the fact that the narrow sides are small compared to the surfaces against which the spacer and flow guide elements rest, a specially shaped flow channel on the small side surfaces can be dispensed with.

[0026] In a modified version, flow-guiding elements are also used on the small side surfaces of the cells. It is also possible to completely or partially close the gaps on the small side surfaces with spacers, which can increase mechanical load capacity and optimize cell attachment.

[0027] Overall, the design according to the application achieves both a stable attachment of the cells in the battery housing and a constant geometry of the flow chambers, which is relevant for immersion cooling. At the same time, the spring element, which preloads a complete row of cells as well as the spacer and flow guide elements inserted between the cells, occupies only a small installation space in relation to the cells and the entire volume in which the spacer and flow guide elements are located.

[0028] The battery housing has, in particular, a cuboidal, rather than cubic, basic shape, with first-order distributors arranged on opposite narrow sides and second-order distributors, which are connected to the first-order distributors, arranged on the top and bottom of the battery housing, and with the electrochemical cells arranged in a matrix between the top and bottom of the battery housing. According to various possible designs, the two first-order distributors each largely fill a narrow side, and the two second-order distributors each largely fill a top or bottom of the battery housing, i.e., more than 50%, in particular more than 80%.

[0029] The planar second-order distributors do not necessarily have an internal structure. For example, the second-order distributors can be designed as planar distribution chambers located in planes parallel to the stacking direction of the electrochemical cells.

[0030] Optionally, at least one pressure relief device, which can be designed as a rupture disc or a pressure relief valve, is located in the upper area of ​​the battery housing. Furthermore, vent valves can be installed, particularly at the corners of the battery housing.

[0031] The pressure relief device serves, in particular, to discharge substances that escape from the electrochemical cells due to deviations from the intended operating parameters. The individual electrochemical cells can have predetermined breaking points for this purpose. It is also possible for the predetermined breaking points of the electrochemical cells to be located in the lower area of ​​the battery housing. In such cases, for example, the predetermined breaking points can be aligned with separate openings in a housing base of the battery housing. Alternatively, the predetermined breaking points can be connected to channels formed in a tray of the battery housing.

[0032] The spring element, i.e. the preload element, which applies a preload force to a row of cells in the battery, is designed, for example, as a leaf spring, a disc spring, or an arrangement of several springs. Adjustment options can be provided by a separate, inherently rigid element, for example in the form of a disc, on which the spring element is supported. Instead of a preload element designed as a spring, a flat element, for example in the form of an intermediate layer made of an elastic, optionally foamed material, can also be used to mechanically preload the battery cells. Regardless of the material and geometry of the elements against which the cells rest when exerting a compressive force, screws can be provided for adjusting the preload.

[0033] One possible design of a preloading device consisting of several preloading elements provides for individually adjustable plate elements to load a row of electrochemical cells. The plate elements can be adjustable using screws.

[0034] At one point in the immersion fluid circuit, for example, between the battery housing and a pump provided for conveying the dielectric immersion fluid, a filling device can be arranged, which includes a compensation tank for the immersion fluid. Venting devices, apart from the filling device, can be arranged, in particular, at the corners of the cuboid-shaped or otherwise prismatic battery housing.

[0035] To raise the battery cells to a higher temperature level when needed, a heating device can be integrated into the immersion fluid circuit. Such a heating device is powered, for example, electrically or by waste heat from another device, in particular an internal combustion engine.

[0036] Any number of electrical, electronic, or electromechanical components, for example at least one sensor, in particular a temperature sensor and / or a voltage sensor, can be integrated into the immersion fluid circuit. Such components can generally be arranged inside or outside the battery housing. In various possible embodiments of the battery, several busbars, which connect electrochemical cells to one another, are accommodated in a cover of the battery housing. The busbars can, for example, be injection-molded into the cover. It is also possible for the busbars to be held in the cover by integrated elements, for example locking lugs, or separate elements, for example fixing clips. The cover can generally be made of electrically non-conductive material, in particular plastic, or of electrically conductive material.In the latter case, the busbars can be provided with an electrically insulating sheath on several sides.

[0037] Regardless of the material or materials from which the cover is made, a template placed over the battery cells already in the battery housing can determine the positions of the busbars during battery production. Depending on the manufacturing process, the template can either remain in the battery or be removed from the battery before production is completed.

[0038] The method according to the application for cooling a battery comprising several electrochemical cells provides for an immersion fluid to be passed through meandering channels that are at least partially connected in parallel in terms of flow. These channels are formed between the electrochemical cells and are kept open by means of rigid spacer and flow guide elements. Spacer and flow guide elements, which are placed in several channels that are connected in parallel in terms of flow, are held under mechanical tension by the force of a spring element. The immersion fluid is passed via first-order distributors and subsequent second-order distributors to the meandering channels defined by the spacer and flow guide elements, or is discharged from these channels.The first-order distributors are located in planes parallel to the spacing and flow-guiding elements, while the second-order distributors, to which the aforementioned parallel channels are directly connected, are located in planes orthogonal to these. In particular, the immersion fluid flows within the battery housing, in which the electrochemical cells, electrically interconnected in any desired manner, along surfaces of electrically conductive busbars, for example, plate-shaped or cuboid-shaped busbars, which connect individual electrochemical cells to one another and are integrated into a cover of the battery housing in one of the ways already described.

[0039] The battery according to the application, which can be temperature-controlled by the method according to claim 20, is particularly suitable for regular rapid charging due to the optimized heat transfer between the cells and the immersion fluid, especially when the battery is designed as a traction battery for a vehicle. Use of the battery in a stationary system is also conceivable.

[0040] Several embodiments of the invention are explained in more detail below with reference to a drawing. In the drawings:

[0041] Fig. 1 a battery tempered by immersion cooling in perspective view,

[0042] Fig. 2 shows an exploded view of a battery constructed largely in accordance with the battery shown in Figure 1,

[0043] Fig. 3 the battery according to Fig. 1 in plan view,

[0044] Fig. 4 and 5 show the battery according to Figures 1 and 3 in sectional views,

[0045] Fig. 6 shows a side surface of the battery according to Fig. 1 including structures for supplying immersion fluid, Fig. 7 shows a side view of a modified possibility of supplying immersion fluid to cells of a battery compared to the design according to Fig. 1,

[0046] Fig. 8 in a representation analogous to Fig. 6 a side surface of the battery according to Fig. 1 including structures for the return of immersion fluid,

[0047] Fig. 9 the bottom of the battery according to Fig. 1 ,

[0048] Fig. 10 Components inside the housing of the battery according to Fig. 1 in plan view,

[0049] Fig. 11 and 12 sectional views of the arrangement according to Fig. 10,

[0050] Fig. 13 a detail from Fig. 12 including a spring element,

[0051] Fig. 14 shows an alternative embodiment of a spring element of a battery in a representation analogous to Fig. 13,

[0052] Fig. 15 a spacing and flow guide element of a battery,

[0053] Fig. 16 a detail of a battery including several spacing and flow guiding elements in plan view,

[0054] Fig. 17 shows a clamping frame of a battery in perspective view, Fig. 18 shows a section of the clamping frame and battery components located therein,

[0055] Fig. 19 shows a section of a battery with an elastic intermediate layer for mechanical prestressing of battery cells,

[0056] Fig. 20 the arrangement according to Fig. 19 in plan view,

[0057] Fig. 21 shows a section of a side view of a battery with separately adjustable plate elements, which are provided for applying a preload force to a row of battery cells,

[0058] Fig. 22 shows a sectional view of a detail of the arrangement according to Fig. 21,

[0059] Fig. 23 the top of a battery cover,

[0060] Fig. 24 the underside of the lid according to Fig. 23,

[0061] Fig. 25 a section AA through the cover according to Fig. 23 and 24,

[0062] Fig. 26 a section BB through a battery including a cover and several safety valves,

[0063] Fig. 27 the underside of the cover of the battery according to Fig. 26,

[0064] Fig. 28 shows another cover of a battery, Fig. 29, 30 the cover according to Fig. 28 in different stages of production,

[0065] Fig. 31 a battery cover! with modified fixing of busbars compared to the variant according to Fig. 29 and 30,

[0066] Fig. 32 another battery cover with busbars held in it,

[0067] Fig. 33 a template that can be used in the manufacture of a battery cover,

[0068] Fig. 34, 35 different variants of busbars for batteries,

[0069] Fig. 36, 37 Sections of the busbar according to Fig. 35,

[0070] Fig. 38, 39 further variants of busbars for batteries,

[0071] Fig. 40 a battery in a sectional view,

[0072] Fig. 41 a bottom of a battery,

[0073] Fig. 42 in a representation analogous to Fig. 40 the battery having the base according to Fig. 41,

[0074] Fig. 43 Structures of a bottom of another battery,

[0075] Fig. 44 shows the battery having the base according to Fig. 43, Fig. 45 shows a battery system intended for use in a vehicle including the battery according to Fig. 1.

[0076] Unless otherwise stated, the following explanations refer to all embodiments. Corresponding or essentially equivalent parts are identified by the same reference numerals in all figures.

[0077] A battery system, designated overall by reference numeral 10, comprises a rechargeable battery 1 whose battery housing 3 has a cuboidal basic shape. The battery housing 3 has a housing width GB, a housing height GH, and a housing depth GT, where GH < GT < GB.

[0078] A plurality of electrochemical cells 2, i.e., battery cells, are temperature-controlled by immersion cooling. A dielectric fluid is used as the immersion fluid. To supply the immersion fluid to the battery cells 2, an inlet manifold 4, referred to as a first-order flat manifold, is located on a first narrow side of the battery housing 3. The width of the first-order flat manifold 4, specified as V4B, corresponds at least approximately to the housing width GB. Specifically, V4B > 0.8 GB. The maximum width V4B of the inlet manifold 4 corresponds to the housing width GB. The height of the inlet manifold 4 is specified as V4H and is 80% to 100% of the housing height GH. The inlet manifold 4 thus covers more than 50% of the area of ​​the narrow side of the battery housing 3, against which the inlet manifold 4 rests.The stacking direction indicated by SR, in which the battery cells 2 are stacked within the battery housing 3, is aligned normal to the plane in which the inlet manifold 4 is located.

[0079] On the side of the battery housing 3 opposite the distributor 4 is a collector 5, which generally also represents a first-order planar distributor. The collector 5 is arranged parallel to the distributor 4 and has corresponding dimensions V4B, V4H. From the inlet distributor 4, the immersion fluid is passed on to a second-order planar distributor 6, which is located on the top side of the battery housing 3. In a similar manner, a second-order planar distributor 7, which is located on the bottom side of the battery housing 3, is connected to the collector 5. The terms "top side" and "bottom side" refer to the arrangement shown in Figures 1 and 2 and do not imply any statement about the actual orientation of the battery 1 in space.

[0080] Within the flat second-order distributor 6, in the exemplary embodiment according to Fig. 1, a plurality of mutually parallel upper inlet transverse channels 8 are formed, which taper in the flow direction of the immersion fluid, i.e. with increasing distance from the inlet distributor 4. Each upper inlet channel 8 is assigned to a row 23 of battery cells 2. Channel sections 9 extend from the upper inlet transverse channel 8 and guide the immersion fluid between the individual battery cells 2 of a row 23. In contrast to the design according to Fig. 1, in the exemplary embodiment according to Fig. 2, the second-order distributors 6, 7 are in the form of distributor spaces 6, 7 without internal structuring. The flat distributor spaces 6, 7, which are located above and below the battery cells 2, respectively, have a width V6B and a depth V6T. As can be seen from Fig.As can be seen from Fig. 2, the extent of the distribution spaces 6, 7 corresponds almost entirely to the dimensions of the top and bottom of the battery housing 3. This means that all battery cells 2 are arranged between the two mutually parallel distribution spaces 6, 7. As can also be seen from Fig. 2, in the upper region of the first-order distributor 4 there are several outflow slots from which the immersion fluid enters the distribution space 6. In an analogous manner, the immersion fluid is guided from the lower distribution space 7 into the collector 5.

[0081] In general, flow channels, regardless of their location in the immersion fluid circuit (designated 20) are designated by 11. Flow channels 11 include meandering flow channels 12, whose meandering shape is determined by spacer and flow guide elements 15, which will be discussed in more detail below. Mounting contours 13 are visible on the outside of the battery housing 3. Connection or connecting elements 14, some of which are referred to as busbars, are arranged partly inside and partly outside the battery housing 3.

[0082] In the embodiment shown in Fig. 1, the immersion fluid flows from bottom to top in the inlet manifold 4, as also shown in Fig. 6. An alternative embodiment, in which the immersion fluid flows from top to bottom in the inlet manifold 4, is illustrated in Fig. 7.

[0083] Regarding the recirculation of the immersion fluid in the collector 5, various design options also exist. Fig. 8 shows the design according to Fig. 1, in which the immersion fluid flows from bottom to top in the collector 5. In an alternative design not shown, a flow in the collector 5 from top to bottom is also possible. Such a design would be compatible with the variant of the inlet distributor 4 shown in Fig. 7.

[0084] As regards the simplified embodiment already explained with reference to Fig. 2, in which the flat distributors 6, 7 of the second order are designed as flat distributor spaces without internal structuring, it has been shown that, despite the lack of inlet or collecting channels connected in parallel to one another in terms of fluid technology in the distributor spaces 6, 7, a uniform fluid distribution to the battery cells 2 and thus also a uniform temperature control is achieved with a good approximation.

[0085] If the immersion fluid flows from the upper flat distributor 6, optionally via the upper inlet transverse channels 8, between the battery cells 2, longitudinal webs 30 and transverse webs 31, which are provided by each spacing and flow-guiding element 15 and abut the adjacent battery cells 2, ensure the meandering shape of the flow channels 12. Two meandering flow channels 12 of equal length are formed through each of the flat spacing and flow-guiding elements 15. The arrangement of a row 23 of battery cells 2 and associated spacing and flow-guiding elements 15, which are each inserted between two battery cells 2, is prestressed by a spring element 16, generally referred to as a tensioning element or prestressing element, which is located within the battery housing 3.Forces generated, among other things, by the spring element 16, i.e., the tensioning element, are absorbed by tension elements 27, which are assigned to the battery housing 3. Tension screws, which are screwed into the tension elements 27, are designated 26. In both the embodiment according to Fig. 13 and the embodiment according to Fig. 14, the tensioning element 16 comprises several disc springs 17. In the variant according to Fig. 14, a compensating element 18 in the form of a disc is additionally present. The compensating element 18 enables tolerance compensation through so-called shimming and is accordingly also referred to as a shim disc.

[0086] Further details are shown, among others, in Figures 10 and 11. These show the rows 23 of battery cells 2 that are electrically connected to one another by connecting elements 24. The immersion fluid is supplied and discharged via inlet-side flow cross-sections 28 and outlet-side flow cross-sections 29, which are located above and below the cells 2, respectively. The cover of the battery housing 3, located above the battery cells 2, is designated 61.

[0087] The flow cross-sections 28, 29 are fluidically connected to the first-order flat distributors 4, 5 via the second-order flat distributors 6, 7. The flat distributor 4 forms, among other things, a lateral inlet channel 19. Within the flat distributor 5, there is, among other things, a lateral return channel 25. The latter return channel 25 is connected to a return cross channel 21 located in the flat distributor 7, as well as channel sections 22 that connect to the lower return cross channel 21 and are also located in the second-order flat distributor 7.

[0088] Fig. 17 shows a clamping frame 53 associated with the battery housing 3, which is provided for accommodating the rows 23 of battery cells 2. The clamping frame 53 comprises side parts 54, 55 and intermediate walls 56 and is particularly suitable for use in a battery 1 according to Fig. 18, in which, among other things, several prestressing elements 15 can be seen. In contrast to the variant according to Fig. 15, the prestressing elements 15 according to Fig. 18 are elastic, so that the need for separate elastic elements is not given in this case.

[0089] Another possibility for applying a preload force to a row 23 of battery cells 2 is illustrated in Figures 19 and 20. Here, the function of the preload elements 16 is taken over by elastic intermediate layers 57, which are located within the clamping frame 53.

[0090] In the embodiment shown in Figures 21 and 22, there are several adjacent plate elements 58, each associated with a row 23 of battery cells 2. Adjusting screws 59 allow the plate elements 58 to be individually adjusted, thus varying the compressive force acting on the associated row 23 of battery cells 2. Screws 60 are screwed into the intermediate walls 56 of the clamping frame 53.

[0091] Fig. 23 shows a possible design of the cover 61 of the battery 1, viewed from the top of the battery housing 3. Stiffening structures of the cover 61 are designated by 62. Bayonet closures 63 can also be seen, into which safety valves 42 (not shown here) can be inserted. By way of example, sensor lines 72 are shown in Fig. 24, which connect busbars 14 to an interface 84. Furthermore, a seal 64 is located on the underside of the cover 61 of the battery housing 3, shown in Fig. 24, as can also be seen from the section according to Fig. 25. Fastening holes in the cover 61 are designated by 67. In the design according to Figs. 23 to 26, the individual busbars 14 have lateral recesses 65, rectangular in the present case, in which recesses 65, within the finished cover 61, material from which the cover 61 is made is located.In principle, the cover 61 can be made of metallic or non-metallic material, in particular plastic, wherein the design of the busbars 14 is adapted to the electrical properties of the cover 61. The structure of a complete battery 1 including cover 61 and safety valves 42 is shown in Fig. 26. Fig. 27 shows the cover 61 of the battery housing 3 of the battery 1 according to Fig. 26 from below. In this case, unlike in the exemplary embodiment according to Fig. 23, the safety valves 42 are to be screwed into screw-in openings 66 which are located in the cover 61. For this purpose, there are threaded holes in the cover 61. Alternatively, connections between the cover 61 and the safety valves 42 can be established via adapters (not shown).

[0092] Various steps for producing a cover 61 of a battery housing 3 are shown in Figures 28 to 30. First, there are through-openings 68 accessible from the top of the cover 61. At this stage of production (Figures 28, 29), it is assumed that the busbars 14 are already firmly embedded in the cover 61 by plastic injection molding. After the busbars 14 located in the cover 61 have been welded to the electrochemical cells 2, the through-openings 68 are filled, as shown in Figure 30, to form filling regions 69.

[0093] A modified method of securing the busbars 14 in the cover 61 is outlined in Fig. 31. In this case, securing clips 70 are provided to hold the busbars 14 in the cover 61. In the variant according to Fig. 32, each busbar 14 has locking lugs 71 with which it hooks into the cover 61.

[0094] Another variant for assembling the busbars 14 and the cover 61, as shown in Fig. 33, provides for the use of a template 73. Sensor lines 72, which are to be connected to the busbars 14, are integrated into the template 73. The busbars 14 are inserted into the template 73 and secured therein, whereby, among other things, methods already explained in connection with the cover 61 can be used for securing them. After the position of the electrochemical cells 2 has been detected, for example visually, the template 73 together with the busbars 14 is placed on the assembly of cells 2, and the busbars 14 are welded to the corresponding electrodes of the battery cells 2. The cover 61 is then placed on the battery housing 3 and screwed in place. The template 73 remains in the battery housing 3.

[0095] In a modified variant, the template 73 is removed after the busbars 14 have been welded. For this purpose, predetermined forces are applied to the template 73, causing the template 73 to tear off at defined locations near the busbars 14. In this case, the sensor lines 72 are not integrated into the template 73 and must be mounted separately after the template 73 has been removed.

[0096] Figures 34, 35, 38, and 39 illustrate various busbars 14 that can be combined with previously explained variants of covers 61. Figures 36 and 37 show sections of the busbar 14 according to Fig. 35. According to Fig. 34, the busbar 14 is designed as a monolithic metal block with lateral recesses 65. During plastic injection molding, i.e., during the manufacture of the cover 61, plastic flows into these recesses 65, which are located on four sides of the busbar 14, so that a positive, non-destructively detachable connection is created between the cover 61 and the busbars 14. At the same time, sensor lines 72 and interfaces connected to these lines can be integrated into the cover 61. In order to enable the various components of the lid 61 to be recycled separately according to materials, the lid 61 has mechanically weakened areas at defined locations, which may in particular be in the form of the filling areas 69 mentioned above.Examples of possible materials for the production of the busbars 14 are alloys based on light metal or copper.

[0097] In the variant according to Figures 35 to 37, the busbar 14 has a metallic core 74 and an electrically insulating sheath 75 made of plastic. In this design, the busbar 14 is also suitable for use in a cover 61 made of metal. As can be seen from Figure 35, unlike in the design according to Figure 34, there are no recesses on the side surfaces of the busbar 14, but rather locking lugs 71, as already mentioned in connection with Figure 32. The underside of the busbar 14 according to Figure 35 is free of any insulating coating. In the variants according to Figures 38 and 39, the busbar 14 is constructed from one or two superimposed sheet metal strips 77, 78. In the center of the at least one sheet metal strip 77, 78, as can be seen from both figures, a curved section referred to as an S-section 76 is formed.The S-section 76, which has the shape of a wave, serves to compensate for tolerances and to absorb loads occurring during operation of the battery 1, which may result from relative movements between cells 2.

[0098] Figures 40 to 44 refer to different variants of batteries 1 with the possibility of media discharge from the battery housing 3. In all variants, the individual cells 2 have predetermined breaking points 79, which are located either on the top side (Fig. 40) or on the bottom side (Fig. 41 to 44) of each electrochemical cell 2.

[0099] In the variant according to Fig. 40, the housing base of the battery housing 3, designated 80, is closed. Should a predetermined breaking point 79 of a cell 2 open, flowable material escapes, as illustrated by arrows in Fig. 40, through at least one of the screw-in openings 66—alternatively: through at least one bayonet lock 63—and at least one of the safety valves 42 (not shown here).

[0100] The variant according to Figures 41 and 42 differs from the variant according to Figure 40 in that there are openings 81 in the housing base 80, whereas the housing cover 61 is closed. Each opening 81 is assigned to a predetermined breaking point 79.

[0101] A variant shown in Figures 43 and 44, which is further developed compared to the variant according to Figures 41 and 42, is characterized in that a tray 82 is formed on the housing base 80. Numerous channels 83 connected to the predetermined breaking points 79 of the individual cells 2 are formed in this tray, which enables central fluid drainage through a drainage opening 85 in the lower region of the battery 1.

[0102] Figure 45 shows the connection of the immersion fluid circuit 20 to a cooling water circuit 32 in a motor vehicle. The cooling water circuit 32 comprises a cooler 33, a fan 34, a pump 35, and a control module 36, which is linked to other vehicle components. A valve within the cooling water circuit 32 is designated 37. A heat exchanger 38 represents both a component of the cooling water circuit 32 and a component of the immersion fluid circuit 20.

[0103] Instead of the cooling water circuit 32, a refrigerant circuit can also be used to transfer heat between the circuit in question and the immersion fluid. In the case of a refrigerant circuit, the pump 35 is replaced by a refrigerant compressor and the valve 37 by an expansion valve.

[0104] Within the immersion fluid circuit 20, immersion fluid lines are generally designated 52. The immersion fluid lines 52 are hermetically separated from the cooling water lines designated 51. A variable distribution of the immersion fluid flow between the heat exchanger 38 and a heating device 40 is possible by means of a control valve 39.

[0105] Immersion fluid is refilled as needed via a filling device designated overall by 44. The filling device 44 comprises a filling module 45 inserted into the immersion fluid circuit 20 and a compensation tank 46 containing a membrane 47. 48 denotes a valve associated with the filling device 44.

[0106] The immersion fluid circuit 20 further comprises a pump 49 and a filter 50. As can also be seen from Fig. 45, there are vent valves 41 located at corners in the upper region of the battery housing 3. A sensor 43 detects conditions within the battery housing 3. A safety valve 42, the only one in the configuration according to Fig. 45, is positioned such that in the event of an inadmissible pressure load, the smallest possible amount of immersion fluid escapes from the housing 3, thus maintaining the possibility of cooling the battery 1 as far as possible.

[0107] List of reference symbols

[0108] Battery electrochemical cell, battery cell

[0109] Battery housing flat first-order distributor on a first narrow side of the battery housing, inlet distributor flat first-order distributor on a second narrow side of the battery housing, collector flat second-order distributor on the top side of the battery housing, distribution chamber flat second-order distributor on the bottom side of the battery housing,

[0110] Distribution room upper inlet cross channel

[0111] Canal section, adjacent to the upper inlet cross canal

[0112] Battery system

[0113] Flow channel, general

[0114] meandering flow channel

[0115] Mounting contour

[0116] Connection or connecting element, busbar

[0117] Distance and flow guide element

[0118] Spring element, preload element

[0119] Disc spring

[0120] Compensation element, disc side inlet channel

[0121] Immersion fluid circuit lower return cross channel

[0122] Channel section, connected to the lower return cross channel

[0123] Series of battery cells

[0124] Connecting element side return channel

[0125] Tension screw tension element

[0126] Flow cross-section, inlet side

[0127] Flow cross-section, outlet side

[0128] Longitudinal web

[0129] crossbar

[0130] Cooling water circuit

[0131] cooler

[0132] fan

[0133] Pump in the cooling water circuit

[0134] Control module

[0135] Valve in the cooling water circuit

[0136] heat exchanger

[0137] control valve

[0138] Heating device

[0139] Vent valve on the battery housing

[0140] safety valve

[0141] sensor

[0142] Filling device

[0143] Filling module

[0144] Expansion tank

[0145] membrane

[0146] Valve in the filling device

[0147] Pump in the immersion fluid circuit

[0148] filter

[0149] Cooling water line

[0150] Immersion fluid line

[0151] Tension frame

[0152] side panel

[0153] side panel

[0154] Partition wall elastic intermediate layer movable plate element

[0155] Adjusting screw

[0156] Screw 61 cover

[0157] 62 Stiffening structure

[0158] 63 bayonet lock

[0159] 64 Seal

[0160] 65 recess

[0161] 66 screw opening

[0162] 67 Mounting hole

[0163] 68 passage opening

[0164] 69 Backfill area

[0165] 70 fixing clip

[0166] 71 locking lug

[0167] 72 Sensor cable

[0168] 73 Stencil

[0169] 74 Metallic core

[0170] 75 Sheath, insulating

[0171] 76 S-section

[0172] 77 metal strips

[0173] 78 metal strips

[0174] 79 Predetermined breaking point

[0175] 80 Case back

[0176] 81 Opening

[0177] 82 tub

[0178] 83 Channel

[0179] 84 Interface

[0180] 85 discharge opening

[0181] GB Case width

[0182] GH case height

[0183] GT case depth

[0184] SR stacking direction

[0185] V4B Width of the first-order distributor

[0186] V4H Height of the first order distributor

[0187] V6B Width of the second-order distributor

[0188] V6T Depth of the second order distributor

Claims

Patent claims 1 . Battery (1) comprising electrochemical cells (2), wherein a temperature control of the electrochemical cells (2) is provided by means of immersion cooling, comprising - a battery housing (3) with a prismatic basic shape, wherein the individual electrochemical cells (2) are also each prismatically shaped, - at least two pairs of flat, fluidically connected distributors (4, 5, 6, 7) for supplying and discharging immersion fluid, wherein distributors (4, 5, 6, 7) belonging to one and the same pair are arranged on two adjacent sides of the battery housing (3) which enclose a finite angle with each other, and each distributor (4, 5, 6, 7) belonging to a first pair of distributors (4, 5, 6, 7) is opposite a distributor (4, 5, 6, 7) of a further pair of distributors (4, 5, 6, 7), - meandering flow channels (12) which are formed between electrochemical cells (2) and which connect the flat distributors (4, 5, 6, 7) to one another and into which spacing and flow-guiding elements (15) which are not elastically flexible to a technically relevant extent are inserted, wherein component groups which are formed from a plurality of cells (2) and spacing and flow-guiding elements (15) which are mechanically connected in series are each loaded by the force of at least one prestressing element (16).

2. Battery (1) according to claim 1, characterized in that the battery housing (3) has a cuboid-like, not cube-shaped basic shape, with first-order distributors (4, 5) on opposite narrow sides and second-order distributors (6, 7), which are connected to the first-order distributors (4, 5), on the top and bottom of the battery housing (3), with the electrochemical cells (2) being placed in matrix form between the top and bottom of the battery housing (3).

3. Battery (1) according to claim 2, characterized in that the two distributors (4, 5) of the first order each have a narrow side and the two distributors (6, 7) second order each fill a top or bottom side of the battery housing (3) to a large extent, i.e. more than 50%.

4. Battery (1) according to claim 2 or 3, characterized in that the second-order distributors (6, 7) are designed as flat distributor spaces having no internal structuring and lying in planes parallel to the stacking direction (SR) of the electrochemical cells (2).

5. Battery (1) according to one of claims 1 to 4, characterized by at least one pressure relief device (42), namely a bursting disc or a pressure relief valve, in the upper region of the battery housing (3).

6. Battery (1) according to one of claims 1 to 5, characterized by numerous predetermined breaking points (79) in the lower region of the battery housing (3), each associated with an electrochemical cell (2).

7. Battery (1) according to claim 6, characterized in that the predetermined breaking points (79) are aligned with separate openings (81) in a housing base (80) of the battery housing (3).

8. Battery (1) according to claim 6, characterized in that channels (83) in a trough (82) of the battery housing (3) are connected to the predetermined breaking points (79).

9. Battery (1) according to one of claims 1 to 8, characterized by at least one mechanical compensating element (18) on which the prestressing element (16) is supported.

10. Battery (1) according to one of claims 1 to 9, characterized by a filling device (44) arranged between the battery housing (3) and a pump (49) provided for conveying immersion fluid, to which a compensation tank (46) for immersion fluid is to be attributed.

11. Battery (1) according to one of claims 1 to 10, characterized in that vent valves (41) are located in corners of the battery housing (3).

12. Battery (1) according to one of claims 1 to 11, characterized in that prestressing elements (16) are in the form of individually adjustable plate elements (58), each of which loads a row (23) of electrochemical cells (2).

13. Battery (1) according to one of claims 1 to 12, characterized by a heating device (40) integrated into the immersion fluid circuit (20).

14. Battery (1) according to one of claims 1 to 13, characterized in that at least one electrical component, including at least one sensor (43), is integrated into the immersion fluid circuit (20) within the battery housing (3).

15. Battery (1) according to one of claims 1 to 13, characterized in that busbars (14) which connect electrochemical cells (2) to one another are accommodated in a cover (61) of the battery housing (3).

16. Battery (1) according to claim 15, characterized in that the busbars (14) are injection-molded into the cover (61).

17. Battery (1) according to claim 15, characterized in that the busbars (14) are held by integrated or separate elements (71, 70) in the cover (61).

18. Battery (1) according to claim 17, characterized in that the busbars (14) are provided on several sides with an electrically insulating sheath (75).

19. Battery (1) according to one of claims 15 to 18, characterized by a template (73) inserted into the battery housing (3) below the cover (61) and defining the positions of the busbars (14).

20. A method for cooling a battery (1) comprising a plurality of electrochemical cells (2), wherein an immersion fluid is conducted through meandering channels (12) which are at least partially connected in parallel in terms of flow technology, which are formed between the electrochemical cells (2) and are kept open by means of flat, rigid spacing and flow guiding elements (15), wherein spacing and flow guiding elements (15) which are placed in a plurality of channels (12) connected in parallel to one another are held under mechanical tension by the force of at least one prestressing element (16), and wherein the immersion fluid is conducted via first-order distributors (4, 5) and second-order distributors (6, 7) to the meandering channels (12) delimited by the spacing and flow guiding elements (15) or is discharged from these channels (12), wherein the distributors (4,5) first order in planes parallel to the spacing and flow guiding elements (15) and the second order distributors (6, 7), to which the said channels (12) are directly connected, lie in planes orthogonal thereto.

21. Method according to claim 20, characterized in that the immersion fluid flows within a battery housing (3) in which the electrochemical cells (2) are located, inter alia on surfaces of busbars (14) which connect individual electrochemical cells (2) to one another and are integrated into a cover (61) of the battery housing (3).

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