DE102019131818A1 - Battery housing for a battery, a battery with a battery housing and a method for producing a battery - Google Patents

Abstract

The invention relates to a battery housing for a battery (10), the battery housing having a multi-shell structure, a first shell of the battery housing as an inner shell (18) at least partially enclosing an interior of the battery housing and a second shell of the battery housing as an inner shell ( 18) is formed on its outer surface facing away from the inner space at least partially comprehensive outer shell (22). The inner shell (18) has a heat-resistant material, and the outer shell (22) is designed to mechanically support the inner shell (18) as an exoskeleton.

Description

The invention relates to a battery housing for a battery, the battery housing having a multi-shell structure. Here, a first shell of the battery housing is designed as an inner shell at least partially enclosing an interior of the battery housing and a second shell of the battery housing is designed as an outer shell at least partially surrounding the inner shell on its outer surface facing away from the interior. The invention also relates to a battery with a battery housing and a method for producing a battery.

As a battery in the sense of the present invention, a so-called high-voltage battery composed of a large number of battery modules is considered in particular. Such a high-voltage battery is generally designed to provide an electrical voltage in the range of more than 60 V, in particular in a range of several 100 V. A preferred area of application for such a high-voltage battery is in the field of electromobility or electrification of the mobility sector. Such high-voltage batteries are preferably used here as electrical energy stores for at least partially electrically driven motor vehicles. The described configuration, in particular the mentioned high electrical voltage ranges, and the preferred area of application in motor vehicles require that a respective battery housing of such a battery must provide a large number of different properties.

For example, battery housings or housings of a known type are generally designed to be able to absorb forces acting on them from the outside. Forces acting from the outside on the battery housing can arise, for example, when a motor vehicle equipped with a battery collides with an obstacle. The battery housing preferably shields the battery from these external forces.

In addition, housings of a known type are generally designed to meet tightness requirements, in particular with respect to gases. The property of gas tightness comes into play in particular when damage occurs to one or more of the battery modules of the battery and / or to individual battery cells of the battery modules. In the event of damage, for example thermal runaway or burnout of a battery cell, depending on the respective cell chemistry of the battery cell, gases can escape from the defective battery cell. The battery housing preferably shields an outside area surrounding the battery from these gases.

Heat can also develop in the defective battery cell in connection with a case of damage described. The heat development can lead to temperatures in the range of more than 1000 ° C. occurring in an interior of the battery housing, from which the exterior area should likewise be protected by the battery housing.

Another requirement that a battery housing of the type described should meet is to shield electromagnetic radiation that occurs when the battery is in operation from the outside area.

In order to meet the aforementioned requirements, battery housings of the known type are made from solid, mostly metallic housing components. Disadvantageously, these housing components have a high weight, the weight being heavily dependent on a respective battery size and / or a respective location of the battery and being between 10 and 100 kg, in particular more than 100 kg. In addition, the housing components often have to be subjected to downstream manufacturing processes (milling, drilling and / or straightening). The result is high production costs and an increased total weight of a respective motor vehicle within which the battery housing is installed.

From the CN 202159712 U a double-walled housing structure for a lithium-ion battery is known. The double-walled design is intended to ensure improved gas tightness with simultaneous air permeability.

The CN 105789514 B describes a battery structure in which individual battery cells are inserted into a plug-in frame, which is then supplemented by an outer shell. The structure described is intended, in particular, to ensure uniform heat radiation from the battery.

The US 2011/0281152 A1 describes a lithium-ion battery with an encapsulating shell.

The invention is based on the object of providing a battery housing for a battery of the type described above, which is designed to at least partially meet the requirements described above and which at the same time has a reduced weight compared to the known battery housings and / or is more cost-effective to produce.

The object is achieved by the subjects of the independent claims. Advantageous developments of the invention are through the dependent claims, the following description and the figures.

The invention is based on the knowledge that the attempt to combine several functional properties in a single component generally leads to this component having an unnecessarily high weight and / or being unnecessarily complex to manufacture.

The invention provides a battery housing for a battery. The battery housing has a multi-shell structure, a first shell of the battery housing being designed as an inner shell at least partially enclosing an interior of the battery housing and a second shell of the battery housing being designed as an outer shell at least partially surrounding the inner shell on its outer surface facing away from the interior. The inner shell is preferably designed to seal the interior of the battery housing in a gas-tight manner. "At least partially enclosing" is to be interpreted in the context described here to the effect that the inner shell is basically designed as a component completely enclosing the interior, but can have at least one opening which is designed, for example, to lead through an electrical connection. The at least one opening is accordingly preferably sealed in such a way that the inner shell seals the interior in a gas-tight manner from a surrounding exterior.

According to the invention, the inner shell has a heat-resistant material or is formed from a heat-resistant material. A material which does not melt in a temperature range between 500 and 1000.degree. C., in particular in a temperature range between 700 and 800.degree. C., can preferably be used as a heat-resistant material. For example, asbestos or a metallic material can be used as the heat-resistant material. In other words, the inner shell provides at least heat resistance as a property of the battery case. In the event that the inner shell is made of a metallic material or has a metallic material, it not only produces heat resistance, but is also designed to shield electromagnetic radiation. In the event that the inner shell is not formed from a metallic material, the property of electromagnetic shielding can be provided, for example, by an additional metallic foil.

According to the invention, the outer shell is designed to mechanically support the inner shell as an exoskeleton. In other words, according to the invention, the outer shell provides mechanical stability or strength or impact resistance as a property of the battery housing. The outer shell thus provides all the necessary mechanical properties to protect the inner shell and thus the internal battery cells from undesired deformation (for example in the event of a crash). The provision of the mechanical stability by the inner shell can therefore be omitted. In other words, various properties of the housing are divided into several shells.

The advantage of the invention is that properties or functionalities of the battery housing can be divided into several shells. This advantageously simplifies the production of the individual shells and allows a weight reduction, in particular by up to 50% compared to known battery housings, in particular while maintaining or improving the mechanical properties compared to known battery housings.

The invention also includes embodiments which result in additional advantages.

One embodiment provides that the outer shell itself also has a multilayer structure, comprising at least one inner layer facing the inner shell and an outer layer spaced apart from the inner layer by a damping layer. The damping layer preferably has structural elements and is designed to cushion an action of force directed onto a surface of the outer layer facing away from the damping layer, with at least partially reversible deformation of the structural elements. In other words, the outer shell itself has several layers. An inner shell of the outer shell can preferably lie directly against the inner shell or touch it. The damping layer can, for example, be filled with damping structural elements or at least partially filled with these. An insulating foam, for example, can be considered as such a damping structural element. Spring elements can also be arranged as damping structural elements in the damping layer. In the manner of a shock-absorbing layer, the damping layer can accordingly cushion or completely compensate for a force acting on a surface of the outer layer facing away from the damping layer. The production of such a material mixture is very difficult or impossible to implement with a conventional single-shell configuration of the battery housing.

A preferred development provides that the structural elements are designed as at least two sets of struts each running essentially parallel to one another, with one respective struts of the first group and a respective strut of the second group meet with the formation of a respective apex angle in a respective apex area and rest against the inner layer or the outer layer in the respective apex area. In this way, a compression force component of the external force can be absorbed by the structural elements in an advantageous manner, in particular resiliently. The respective apex angle is preferably between 60 and 120 °.

According to an advantageous development, the structural elements in the respective apex area are connected to the inner layer or the outer layer, in particular in one piece. In other words, the structural elements are preferably welded or glued or screwed or riveted to the inner layer or the outer layer in the respective apex area. This connection advantageously also enables the structural elements to absorb shear force components of the external force.

A preferred embodiment provides that the inner shell and the outer shell are designed to be fastened to one another or connected to one another. For this purpose, it can specifically be provided that the inner shell has first latching elements and the outer shell has second latching elements configured to correspond to the first latching elements. The latching elements can be designed, for example, in the form of a plug-socket connection. The outer shell can be connected to the inner shell when it is pushed onto the inner shell by means of the first and second latching elements which are designed to correspond to one another in shape. This results in the advantage of a particularly simple assembly.

The outer shell preferably has two half-shells. A respective half-shell is preferably designed to encompass the inner shell proportionally, in particular in half. This embodiment also enables particularly simple assembly.

According to an advantageous development, a respective half-shell is designed to be slipped or pushed or plugged onto the inner shell. The respective half-shell is preferably already attached to the inner shell in a force-locking manner by being slipped or pushed or plugged onto the inner shell. This advantageously has the result that there is no play or no tolerance between the inner and outer shell and thus mechanical stability is guaranteed.

According to an advantageous development, one of the half-shells has first coupling elements and the other of the half-shells has second coupling elements, the first and second coupling elements having a corresponding shape and being designed to fasten the two half-shells to one another in a position encompassing the inner shell. Fastening can take the form of clipping in or hooking in, for example. A sealing lip is particularly preferably arranged between the half-shells. This has the advantage that the outer shell can be sealed or configured to be gas-tight. In the event of an accident or damage occurring within the battery housing, in particular within the inner shell, the outer shell can thus function as a further barrier to protect an outer space from any gas that may escape. This redundancy ensures particularly safe operation.

According to an advantageous embodiment, at least one temperature control element is arranged between the inner shell and the outer shell and held by the outer shell. The temperature control element can be used, for example, to ensure or set a preferred or predetermined operating temperature of the battery within the battery housing. In a preferred development, the outer shell has recesses, the at least one temperature control element being positively received in a respective recess. This design also allows a particularly simple assembly of the arrangement described here. For example, the outer shell can be equipped with the temperature control element and only then slipped or pushed onto the inner shell.

A fiber-reinforced thermoplastic can be provided as a preferred material for the outer shell. Such a thermoplastic or an organic sheet is a hybrid component that mainly has two components. The first component is usually a fabric mat, which can be formed, for example, from glass fibers and / or carbon fibers and / or aramid fibers. Such a fabric mat has a high mechanical stability or performance. To form an organic sheet, such a mat is usually embedded in a thermoplastic matrix. Corresponding materials are known in principle to the person skilled in the art. The design of the outer shell from a fiber-reinforced thermoplastic offers advantages in particular in terms of production. As is known, organic sheets can be physically formed into three-dimensional parts by heating and subsequent pressing in very short cycle times. In addition, during the reshaping, for example, ribs and / or fastening points and / or other geometries, such as the mentioned latching elements or coupling elements, can be molded on at the same time. At the same time, the material described here offers a clear one Weight savings compared to, for example, metallic materials.

According to a preferred embodiment, a multi-shell battery housing with an inner shell made of asbestos, an outer shell made of a fiber-reinforced thermoplastic and a casing made of a metallic foil can be provided. In this way, the functionalities of heat resistance, mechanical stability and shielding against electromagnetic radiation are implemented and divided into several layers. This division of functionalities into individual layers, each of which has the material property suitable for fulfilling its purpose, advantageously leads to a weight saving overall.

The invention also relates to a battery with a battery housing, battery modules of the battery being arranged in the interior of the battery housing.

The invention also includes further developments of the battery according to the invention which have the features as already described in connection with the further developments of the battery housing according to the invention. For this reason, the corresponding developments of the method according to the invention are not described again here.

The invention also includes a motor vehicle with a battery, the motor vehicle preferably being designed as a motor vehicle, in particular as a passenger vehicle or truck, or as a passenger bus or motorcycle. The invention also includes further developments of the method according to the invention which have features as they have already been described in connection with the further developments of the battery housing according to the invention. For this reason, the corresponding developments of the motor vehicle according to the invention are not described again here.

The invention also relates to a method for producing a battery with a multi-shell battery housing, with battery modules of the battery being arranged in an interior of the battery housing. The method according to the invention comprises a method step which provides for providing a first shell of the battery housing, the first shell being designed as an inner shell which at least partially encloses the interior of the battery housing and has a heat-resistant material. In a further method step, the method according to the invention provides for the arrangement of battery modules of the battery in the interior. In addition, according to the invention, a second shell of the battery housing is provided and plugged onto the inner shell. The second shell here comprises the inner shell on its outer surface facing away from the interior as an outer shell, at least in some areas, and mechanically supports the inner shell as an exoskeleton.

The invention also includes further developments of the method according to the invention which have features as they have already been described in connection with the further developments of the battery housing according to the invention. For this reason, the corresponding developments of the method according to the invention are not described again here.

The invention also includes the combinations of the features of the described embodiments.

• 1 eine schematische Explosionsdarstellung einer Batterie mit einem Batteriegehäuse und Batteriemodulen;
• 2 eine schematische Detaildarstellung eines Abschnitts eines Exoskeletts mit Strukturelementen; und
• 3 eine schematische Darstellung eines Verfahrens zum Herstellen einer Batterie.

Exemplary embodiments of the invention are described below. This shows:

• 1 a schematic exploded view of a battery with a battery housing and battery modules;
• 2 a schematic detailed representation of a section of an exoskeleton with structural elements; and
• 3rd a schematic representation of a method for producing a battery.

The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention which are to be considered independently of one another and which also further develop the invention in each case independently of one another. Therefore, the disclosure is also intended to include combinations of the features of the embodiments other than those illustrated. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

In the figures, the same reference symbols denote functionally identical elements.

1 shows a schematic exploded view of a battery 10 with battery modules 12th . In the schematic exploded view of the 1 are exemplary eight battery modules 12th the battery 10 shown. Above the battery modules 12th are in the 1 other components 14th the battery 10 shown, which are not described in more detail below. This can be, for example, power electronics or a battery management system for the battery 10 act. The 1 shows above and below the eight Battery modules 12th first a respective half-shell 16 as part of an inner shell 18th a battery case of the battery 10 . Above or below a respective half-shell 16 shows the exploded view of the 1 a respective further half-shell 20th as part of an outer shell 22nd . In the lower half of the 1 are between the inner shell 18th and the outer shell 22nd Temperature control elements 24 shown.

2 shows a schematic representation of a section of a respective half-shell 20th the outer shell 22nd . The half-shell 20th the outer shell 22nd has a multilayer structure. The structure includes according to the schematic representation of 2 an inner layer 26th and an outer layer 28 . The inner layer 26th and the outer layer 28 are through one between the two layers 26th , 28 arranged damping layer 30th spaced from each other. Inside the cushioning layer 30th can structural elements 32 be arranged. The structural elements 32 the 2 are as at least two sets of struts each running essentially parallel to one another 34 formed, with only two struts being provided with reference numerals for the sake of clarity. The striving 34 meet with the formation of a vertex angle 36 together. The meeting takes place in a respective apex area 38 .

3rd shows with reference to the in connection with the 1 and 2 designated and described components schematically a method for producing a battery 10 with a multi-shell battery housing, with battery modules 12th the battery 10 are arranged in an interior of the battery housing. In one process step S1 a first shell of the battery housing is provided, the first shell being an inner shell which at least partially encloses the interior of the battery housing and has a heat-resistant material 18th is trained. In one process step S2 become battery modules 12th the battery 10 arranged in the interior. In one process step S3 a second shell of the battery housing is provided. In one process step S4 becomes the second shell on top of the inner shell 18th attached, the second shell being the inner shell 18th on its outer surface facing away from the interior as an outer shell 22nd at least partially includes and the inner shell 18th mechanically supported as an exoskeleton.

Current lithium-ion high-voltage batteries in electrified vehicles are currently built in a metallic housing or battery housing. The metallic housing can either be designed as a deep-drawn part, welded assembly or as a cast part. The housing takes on all mechanical and structural tasks that affect the battery system from the vehicle.

The housing of a lithium-ion battery must meet a wide variety of requirements. The battery housing must be able to absorb the forces that occur and meet tightness requirements in the event of an internal accident or damage. Furthermore, these components or parts of the housing are subject to a very high downstream machining process (e.g. milling, drilling, straightening). As a result, the housing must meet a high degree of dimensional accuracy in production, and thus entails high production costs. Due to the massive housing components, weight and costs are passed on to the vehicle.

The present invention comprises a housing for a battery (traction battery or auxiliary consumer battery). This battery can be designed as a conventional lead or lithium-ion technology. The battery can also be designed in a low or high voltage technology.

The housing of the battery is designed as a simple and structurally weak tub construction made of two shells (see esp. 1 ). The mechanical structure is restored via an external cage ("exoskeleton"). The exoskeleton is preferably made of "organic sheet". The organic sheet is a hybrid component that mainly contains two components. The first component is preferably a fabric mat which can consist of the following materials: glass, carbon, aramid or mixed fibers, which ensures high mechanical performance. These mats are embedded in a thermoplastic matrix. Organic sheets are physically formed into three-dimensional parts by heating and subsequent pressing in very short cycle times. During the forming process, for example ribs, fastening points or other geometries can be molded on at the same time.

The two shells are then preferably mounted around the battery housing, and thus restore the full or major strength of the overall system.

This results in at least the following advantages: Reduction in complexity, reduction in weight and / or production costs while the mechanical performance or stability of the battery remains the same.

For technical implementation, the assemblies can be housed (either as an assembly (ZSB) welded group made of extruded aluminum or is designed as machined cast aluminum) and the housing cover (mostly aluminum deep-drawn part) can be replaced by a sequence of exoskeleton above, deep-drawn tub above, exoskeleton below, deep-drawn tub below (see 1 ).

Overall, the examples show how a structure of a battery, in particular a high-voltage battery, with an external protective structure or an exoskeleton, in particular made of organic sheet, can be provided by the invention.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• CN 202159712 U [0008]
• CN 105789514 B [0009]
• US 2011/0281152 A1 [0010]

Claims (14)

Battery housing for a battery (10), the battery housing having a multi-shell structure, with a first shell of the battery housing as an inner shell (18) at least partially enclosing an interior of the battery housing and a second shell of the battery housing as an inner shell (18) on it The outer surface facing away from the interior is formed at least partially encompassing outer shell (22), characterized in that the inner shell (18) has a heat-resistant material, and the outer shell (22) is designed to mechanically support the inner shell (18) as an exoskeleton. Battery case after Claim 1 , wherein the outer shell (22) has a multilayer structure, comprising at least one inner layer (26) facing the inner shell (18) and an outer layer (28) spaced apart from the inner layer (26) by a damping layer (30), the damping layer (30 ) Has structural elements (32) and is designed to cushion, with at least partially reversible deformation of the structural elements (32), a force acting on a surface of the outer layer (28) facing away from the damping layer (32). Battery case after Claim 2 , wherein the structural elements (32) are designed as at least two sets of struts (34) running essentially parallel to one another, a respective strut (34) of the first set and a respective strut (34) of the second set forming a respective apex angle (36) meet in a respective apex area (38) and bear against the inner layer (26) or the outer layer (28) in the respective apex area (38). Battery case after Claim 3 , wherein the respective vertex angle (36) is between 60 and 120 degrees. Battery case according to one of the Claims 3 or 4th wherein the structural elements (32) in the respective apex area (38) are connected to the inner layer (26) or the outer layer (28), in particular in one piece. Battery housing according to one of the preceding claims, wherein the inner shell (18) has first latching elements and the outer shell (22) has second latching elements configured to correspond to the first latching elements, the outer shell (22) being designed to snap onto the inner shell (18) to be attached and to be connected to the inner shell (18) by engaging the respective locking elements. Battery housing according to one of the preceding claims, wherein the outer shell (22) has two half-shells (16, 20), a respective half-shell (16, 20) being designed to partially, in particular half, surround the inner shell (18). Battery case after Claim 7 , wherein a respective half-shell (16, 20) is designed to be slipped or pushed or plugged onto the inner shell (18). Battery case according to one of the Claims 7 or 8th , wherein one of the half-shells (16, 20) has first coupling elements and the other of the half-shells (16, 20) has second coupling elements, the first and the second coupling elements being designed to correspond in shape and designed to the two half-shells (16, 20 ) to be fastened to one another in a position surrounding the inner shell (18). Battery housing according to one of the preceding claims, wherein at least one temperature control element (24) is arranged between the inner shell (18) and the outer shell (22) and is held by the outer shell (22). Battery case after Claim 10 wherein the outer shell (22) has recesses, the at least one temperature control element (24) being positively received in a respective recess. Battery housing according to one of the preceding claims, wherein the outer shell (22) has a fiber-reinforced thermoplastic component. Battery (10) with a battery housing according to one of the preceding claims, wherein battery modules (12) of the battery (10) are arranged in the interior of the battery housing. A method for producing a battery (10) with a multi-shell battery housing, wherein battery modules (12) of the battery (10) are arranged in an interior of the battery housing, comprising the steps of providing a first shell of the battery housing, the first shell being one of the interior the battery housing at least partially enclosing, a heat-resistant material having inner shell (18) is formed, - arranging battery modules (12) of the battery (10) in the interior, - providing a second shell of the battery housing, - Attaching the second shell to the inner shell (18), the second shell at least partially encompassing the inner shell (18) on its outer surface facing away from the interior as an outer shell (22) and mechanically supporting the inner shell (18) as an exoskeleton.

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