Battery system, motor vehicle with battery system and method for its manufacture

Abstract

Battery system (10), in particular for supplying an electric drive of a motor vehicle with electrical energy, wherein a plurality of modules (12), each containing at least one electrochemical cell and / or power electronics, are received in a receiving structure and a gap filler (20) made of polysulfide-modified epoxy resin is introduced between adjacent modules (12) and / or between modules (12) and the receiving structure, as well as a motor vehicle with such a battery system and a method for its manufacture.

Description

[0001] The invention relates to a battery system, a motor vehicle with such a battery system and a method for producing a battery system or a motor vehicle with such a battery system according to the independent claims.

[0002] Battery systems are known from practice in which a plurality of modules, each containing a battery cell and / or power electronics, are accommodated in a holding structure. The holding structure can be a frame-like structure or a relatively solid, gas-tight housing. The challenge with existing designs is usually to first ensure good mechanical protection of the modules against mechanical damage. This is particularly true when the battery system is part of a motor vehicle. Furthermore, the battery system must be as easy to assemble and, in particular, to disassemble and recycle as possible. This particularly applies to the aspect of recyclability. As a result, such battery systems are often comparatively complex and elaborate, with comparatively solid housings, and are therefore expensive.In addition, the bonding often carried out with adhesives based on thermosets poses a problem with regard to recyclability.

[0003] Battery systems of the type in question are known, for example, from DE 10 2018 219 462 A1. In such a battery, the battery modules are arranged within a battery housing. A non-Newtonian fluid is arranged between the battery modules and the battery housing. This arrangement is intended to ensure that, due to the shear-thickening behavior of the non-Newtonian fluid, it can conform to surfaces subject to tolerances and harden in the event of deformation at a high deformation rate. While this represents an approach to advantageously utilizing the properties of non-Newtonian fluids in battery systems, it does not yet solve the existing challenges regarding easy assembly and disassembly in conjunction with good protection against mechanical damage that arise in practice.

[0004] US 2022 / 0153987 A1 shows the use of a gap filler containing a polysulfide-modified epoxy resin in a battery.

[0005] DE 10 2017 223 438 A1 discloses a battery device for an electrically powered vehicle. The battery device has a free space between a surrounding housing and a battery module, which is filled with a displacement material. The displacement material can be a foam material.

[0006] DE 10 2019 211 088 A1 discloses a battery housing for a battery, in particular for a motor vehicle, whose side wall comprises two side wall elements that form a channel between them. The channel can be designed as a degassing channel.

[0007] The object of the present invention is therefore to provide a battery system, a motor vehicle with such a battery system and a method for producing the same, which combine good protection against mechanical impairments with easy assembly and, in particular, disassembly of the battery system.

[0008] The object is achieved by a battery system, a motor vehicle with such a battery system, and a method for producing such a battery system or such a motor vehicle according to the independent claims. The dependent claims relate to advantageous embodiments.

[0009] The battery system is used in particular to supply an electric drive system of a motor vehicle with electrical energy.

[0010] The battery system comprises a plurality of modules housed in a mounting structure. The mounting structure serves primarily to fix the modules in place. Furthermore, the mounting structure can provide protection against mechanical interference, particularly damage.

[0011] The receiving structure can have a base region forming a floor. The modules can be arranged on the base region, in particular in a regular, geometric grid. The receiving structure has a surrounding region forming a lateral enclosure. Such a surrounding region can extend upwards, in particular in an at least substantially vertical direction, from the base region. The receiving structure can further have a cover to enclose the receiving structure at the top. The spatial directions mentioned explicitly or implicitly above relate in particular to the orientation of the battery system during its intended use, in particular as a component of a motor vehicle.

[0012] The modules each contain at least one electrochemical cell and / or power electronics. The electrochemical cell can be a lithium-ion cell. The power electronics can be, for example, a pulse-controlled inverter.

[0013] The object is achieved in particular by inserting a gap filler made of polysulfide-modified epoxy resin between modules and the receiving structure, in particular between adjacent modules and between modules and the receiving structure.

[0014] Gap fillers of the type in question are also referred to as gap fillers. The gap filler is used, in particular, to bond adjacent modules and / or the modules and the supporting structure. Polysulfide-modified epoxy resin has the special property of allowing cracks in the gap filler to heal through the reorganization of sulfur bonds. This property allows the gap filler to accommodate the modules in the supporting structure, whereby, in particular, the special crack healing properties ensure ideal embedding of the modules in the supporting structure.

[0015] At the same time, the gap fillers made of polysulfide-modified epoxy resin offer good recycling properties. Individual modules can generally be removed from the mounting using such gap fillers relatively easily, which is not the case with the thermoset adhesives commonly used as gap fillers, for example. In addition, the gap filler itself has better recycling properties than other gap fillers, especially those made from thermoset adhesives.

[0016] Furthermore, the polysulfide-modified epoxy resin can be processed into geometrically defined semi-finished products, such as films. Due to their crack-healing properties, these semi-finished products can essentially "fuse" together after processing, thus creating an ideal embedding of the modules.

[0017] The polysulfide-modified epoxy resin could, for example, be Thioplast® EPS 25 from Akzo Nobel. This is commercially available and has proven suitable for the present application.

[0018] The gap filler can contain an additive that increases its thermal conductivity. For example, particles that increase its thermal conductivity can be distributed throughout the gap filler. Due to its crack-healing properties, a gap filler made of polysulfide-modified epoxy resin is particularly well-suited for embedding particles. Such particles can then increase the thermal conductivity of the gap filler, allowing the gap filler to achieve a good thermal connection between components.

[0019] The additive is contained primarily in the gap filler located between the modules and the base area of ​​the support structure. The base area is particularly well-suited for dissipating heat from the battery system. Therefore, increasing the thermal conductivity of the gap filler located between the modules and the base area is particularly useful.

[0020] The gap filler comprises a propellant as a component. The propellant can be, for example, expandable microspheres. Expandable microspheres are, in particular, gas-filled polymer structures, for example, gas-filled polymer spheres. Such microspheres are commercially available, for example, under the name Expancel® 031DU40. When heated, the gas expands and the polymer structures expand, while in particular the polymer shell is retained. This increase in volume allows the microspheres to act as a propellant. Alternatively and / or additionally, the gap filler can also comprise another propellant, for example, a gas-releasing propellant. The propellant can be contained in the gap filler, in particular, in the form of particles distributed therein.

[0021] The propellant is contained in particular in the gap filler arranged between adjacent battery cells and / or the surrounding area forming a lateral enclosure. If the battery system heats up during operation, the expansion caused by the propellant can displace the gap filler into any remaining cavities in the battery system, thus achieving optimal embedding of the modules. In addition, due in particular to the crack-healing properties, any cracks in the gap filler that arise during the expansion and displacement can heal again. Furthermore, by displacing the gap filler into appropriately designed cavities, undercuts can be formed, which lead to even better fixation of the modules in the battery system.

[0022] The floor area and the enclosure area can be detachably connected. Such a detachable connection between the floor area and the enclosure area offers the advantage that the battery system can be disassembled and reassembled. This allows parts of the battery system to be replaced if they become damaged.

[0023] The base area and the surrounding area can be detachably connected to one another, in particular by means of snap-on fasteners. Snap-on fasteners offer easy assembly and disassembly while simultaneously providing secure fixation with respect to forces oriented in directions perpendicular to the direction in which the connecting partners of the snap-on fasteners are brought into engagement with one another. If the battery system is used in a motor vehicle, for example, forces in horizontal directions, such as those primarily acting on the battery system when the vehicle is moving, can be easily absorbed by the fasteners. At the same time, the fasteners can be easily detached from one another by applying a tensile force in a vertical direction.

[0024] The convex, snap-fastener-like connecting elements can be created on the base area, for example, using additive processes such as cold metal transfer welding or laser powder deposition welding. Corresponding complementary concave structures can be molded into the surrounding area. This can be achieved, for example, by integrating connecting elements, such as socket-like snap-fastener counterparts, into the surrounding areas using an injection molding process. Alternatively and / or additionally, corresponding connecting elements can be connected to the base area and / or the surrounding area, for example, by bonding or gluing them on.

[0025] Through the interaction of the gap filler with such a detachable fixing area at the floor area, in particular by means of detachable connecting elements, a mechanically robust yet demountable battery system can be created.

[0026] The enclosure may be a plastic structure. The plastic structure may, in particular, be a fiber-reinforced plastic structure, for example, a glass-fiber-reinforced plastic structure. Such an enclosure can be manufactured cost-effectively and yet offers the possibility of providing a battery system that is well protected against mechanical damage, particularly in conjunction with the other features of the battery system described here.

[0027] The lateral enclosure of the support structure is double-walled, at least in some areas. The enclosure has an inner wall and an outer wall. This double-walled design of the enclosure improves the protection of the modules against mechanical damage.

[0028] The inner wall of the enclosure is designed to be permeable to the gap filler. For this purpose, the inner wall can, for example, have openings through which the gap filler can pass. This allows the gap filler, particularly due to the propellant, to be pushed through the inner wall into a cavity formed between the inner and outer walls. This allows undercuts to be formed, which contribute to better securing the modules in the battery system.

[0029] The cavity formed between the inner and outer walls can be filled with a dilatant material. A dilatant, or shear-thickening, material has a viscosity that depends on the shear rate. This allows the shear-thickening material to be displaced relatively easily by the slow-moving gap filler as it enters the cavity through the inner wall. At the same time, however, it will offer comparatively high resistance to high-speed deformation of the battery system. The dilatant material can be a polymer, for example, the shock-absorbing polymer commercially available under the name D30®.

[0030] The cavity can initially be only partially filled with the dilatant material. This allows the gap filler to penetrate the cavity and displace dilatant material into an upper, still unfilled area of ​​the cavity. In particular, the dilatant material can be displaced by the gap filler in such a way that the cavity is completely filled.

[0031] The motor vehicle has an electric drive system to drive and / or assist the vehicle's movement. Such drives are characterized by comparatively high power output. Accordingly, they require a powerful energy supply that can also provide a sufficiently large amount of energy to enable the vehicle to travel a sufficiently long range.

[0032] Furthermore, the battery system in motor vehicles is constantly exposed to mechanical forces due to the movement during regular operation and there is also the risk of mechanical impairment in the event of an accident.

[0033] For these reasons, the battery system described above is particularly well suited for use in motor vehicles, since the battery system, due to its design, provides the necessary protection against mechanical damage and, due to the possibility of safely accommodating a large number of modules in the battery system, the required capacities and performance can also be provided.

[0034] The motor vehicle accordingly has a battery system as described above for supplying the drive system with electrical energy. The floor area of ​​the battery system can be a body area of ​​the motor vehicle.

[0035] The body area is primarily made of a metallic material. Such metallic materials offer good thermal conductivity. At the same time, body areas are typically mechanically resilient and can be designed accordingly. Therefore, a body area is advantageously suited to serve as the base area of ​​the battery system. On the one hand, the mechanical forces acting on the battery system can be well absorbed by the body area as a base area. On the other hand, heat generated in the battery system can be easily dissipated via the body area.

[0036] The method for manufacturing a battery system or a motor vehicle described above provides for the gap filler to be introduced into the battery system in the form of geometrically defined semi-finished products. In the form of geometrically defined semi-finished products, the gap filler is easy to handle and process. The properties of the polysulfide-modified epoxy resin enable the individual semi-finished products to "melt" together after insertion, thus ensuring optimal embedding of the modules.

[0037] Semi-finished products can, in particular, be films. Films are well suited for filling the gaps between modules and / or modules and the supporting structure and can be easily applied to flat surface areas.

[0038] The semi-finished products can contain the additive that increases the thermal conductivity of the gap filler and / or the propellant. This allows the additive and / or the propellant to be introduced particularly easily into the desired areas of the battery system by selecting appropriate semi-finished products for each area. For example, semi-finished products containing the additive that increases the thermal conductivity of the gap filler can be introduced between the modules and the base area, while semi-finished products containing the propellant can be introduced between the adjacent modules and / or between the modules and the surrounding area.

[0039] Further practical embodiments of the invention are described below in conjunction with the drawings. They show: Fig. 1 a schematic sectional view of an exemplary battery system immediately after assembly, Fig. 2 a schematic sectional view of the exemplary battery system from Fig. 1 after a certain period of operation.

[0040] The Fig. 1 and Fig. The battery system 10 shown as an example in Figure 2 can be used to supply an electric drive of a motor vehicle and in this context can be a component of the motor vehicle.

[0041] The battery system comprises a plurality of modules 12. The modules can each contain at least one electrochemical cell and / or power electronics. The modules are accommodated in a receiving structure.

[0042] As in the example shown, the receiving structure may comprise a base region 14 that forms a base of the battery system 10. The base region 14 may be a region of a motor vehicle body.

[0043] As in the example shown, the receiving structure further comprises a surrounding area 16 which forms a lateral enclosure of the battery system 10.

[0044] As shown by way of example, the receiving structure may further comprise a cover 18 which closes the battery system 10 at the top.

[0045] As in the example shown, a gap filler 20 is inserted between modules 12 and the surrounding area 16, in particular between adjacent modules 12 and / or between modules 12 and the floor area 14 and / or. The gap filler 20 embeds and / or bonds the modules 12, in particular, in the surrounding structure. The gap filler 20 is a polysulfide-modified epoxy resin.

[0046] As in the example shown, the gap filler 20, which is arranged between modules 12 and the floor area 14, can comprise an additive 22 that increases the thermal conductivity of the gap filler 20. The additive 22 can be an additive 22 in the form of particles, as schematically illustrated by way of example.

[0047] As in the example shown, the gap filler 20 arranged between modules 12 and the surrounding area 16, and in particular the gap filler 20 arranged between adjacent modules, contains a propellant 24. The propellant 24 can be expandable microspheres, as schematically illustrated by way of example.

[0048] As in the example shown, the floor area 14 and the surrounding area 16 can be connected by means of Fig. 1 and Fig. 2 by connecting elements 26 which are only schematically indicated. The connecting elements 26 can be as shown schematically in the Fig. 1 and Fig. 2 are indicated as push-button-like connecting elements.

[0049] As in the example shown, the surrounding area 16 is double-walled, at least in some areas. An inner wall 28 of the surrounding area 16 can have openings 30 through which the gap filler 20 can penetrate into a cavity 34 formed between the inner wall 28 and an outer wall 32 of the surrounding area 16.

[0050] A dilatant material 36 can be arranged in the cavity 34. In this case, the cavity 34 can be filled immediately after the assembly of the battery system 10, as shown in Fig. 1, only partially filled with the material 36.

[0051] The assembly of the Fig. 1 can be carried out, for example, by first providing the base region 14 with the connecting elements 26. Furthermore, the base region 14 can be provided with the gap filler 20. This can be done easily if the gap filler 20 is introduced as a geometrically defined semi-finished product. For example, the gap filler 20 can be applied to the base region 14 as a film, which in particular already contains the additive 22 that increases the thermal conductivity of the gap filler 20.

[0052] The enclosure area 16 can be connected to the base area 14 by means of the connecting elements 26. The modules 12 can be inserted into the enclosure area, and the gap filler 20, in particular also as a geometrically defined semi-finished product, for example as a film, can be introduced between the adjacent modules 12 and between modules 12 and the lateral enclosure area 16. The gap filler 20 used for this purpose can already contain the propellant 24 as a semi-finished product.

[0053] After inserting the modules 12, the cover 18 can be attached.

[0054] The cavities 34 can then be partially filled with the dilatant material in order to Fig. 1 to achieve the state shown schematically.

[0055] When the battery system 10 heats up during operation, the propellant 24 can cause the gap filler 20 to expand, with the result that the gap filler 20 penetrates through the openings 30 in the inner wall 28 into the cavity 34. There, the gap filler 21 emerging through the openings 30 can displace the dilatant material 36, for example, until the cavity 34 is completely filled with the dilatant material 36. This can be achieved, for example, by appropriately dimensioning the amount of propellant. In the area of ​​the inner wall 28, undercuts of the gap filler 20 with the surrounding area 16 are thus created, which further increase the stability of the battery system 10. The state of the battery system 10 that thus arises during operation is shown in Fig. 2 is shown schematically.

[0056] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. List of reference symbols 10 Battery system 12 Module 14 Floor area 16 Enclosure area 18 Cover 20 gap fillers 21 protruding gap filler 22 Additive 24 propellants 26 Connecting element 28 inner wall 30 openings 32 outer wall 34 cavity 36 dilatant material

Claims

[1] Battery system (10), in particular for supplying an electric drive of a motor vehicle with electrical energy, wherein a plurality of modules (12), each containing at least one electrochemical cell and / or power electronics, is accommodated in a receiving structure, wherein a gap filler (20) made of polysulfide-modified epoxy resin is introduced between modules (12) and the receiving structure, wherein the gap filler (20) has a blowing agent (24) as a component, wherein a surrounding area (16) of the receiving structure forming a lateral enclosure is at least partially double-walled with an inner wall (28) and an outer wall (32), so that a cavity (34) is formed between the inner wall (28) and the outer wall (32), characterized by , that the inner wall (28) is designed to be permeable to the gap filler (20). [2] Battery system (10) according to claim 1, characterized by that the gap filler (20) contains an additive (22) which increases the thermal conductivity of the gap filler (20). [3] Battery system (10) according to claim 1 or 2, characterized by that the gap filler (20) comprises expandable microspheres as a component. [4] Battery system (10) according to one of the preceding claims, characterized by that a base region (14) of the receiving structure forming a base and the surrounding region (16) are detachably connected to one another, in particular by means of push-button-like connecting elements (20). [5] Battery system (10) according to one of the preceding claims, characterized by that the cavity (34) is at least partially filled with a dilatant material (36). [6] Battery system (10) according to one of the preceding claims, characterized bythat the inner wall (28) is designed to be permeable to the gap filler (20) by having openings (30) through which the gap filler (20) can pass. [7] Battery system (10) according to claim 5 or 6, characterized by that the dilatant material (36) can be displaced by gap filler (20) penetrating through the inner wall (28) into the cavity (34), in particular in such a way that the displacement of the dilatant material (36) by the gap filler (20) brings about complete filling of the cavity (34). [8] Motor vehicle with an electric drive for effecting and / or assisting the travel movement of the motor vehicle and a battery system (10) according to one of the preceding claims for supplying the drive with electrical energy. [9] Motor vehicle according to claim 8, characterized bythat a floor area (14) of the receiving structure forming a floor is a body area of the motor vehicle. [10] Method for producing a battery system (10) according to one of claims 1 to 7 or a motor vehicle according to one of claims 8 or 9, characterized by that the gap filler (20) is provided in the form of geometrically determined semi-finished products and is introduced into the battery system (10) during assembly of the battery system, in particular wherein the semi-finished products contain the additive (22) and / or the propellant (24) which increases the thermal conductivity of the gap filler (20).

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