Production of a battery comprising a housing

Abstract

The invention relates to a method for producing a battery, having a battery element assembly, which comprises at least one battery element, and a housing, which surrounds the battery element assembly. The housing comprises a base housing (8) that delimits a housing interior (11) for at least partly receiving the battery element assembly and has a housing opening (20), through which the battery element assembly is introduced into the housing interior (11), wherein the housing opening (20) is then closed by a cover of the housing. The invention is characterized in that the base housing (8) is produced by cutting through a blank, the shape of which is designed to comprise the shapes of two base housings (8).

Description

[0001] DESCRIPTION

[0002] Manufacturing a battery with a housing

[0003] The invention relates to a method for producing a battery.

[0004] A battery is an electrochemical storage device for electrical energy. During discharge, the stored chemical energy is converted into electrical energy through an electrochemical redox reaction. In the context of the invention, batteries are understood to include both so-called primary batteries, which are designed for a single discharge and not for recharging, and so-called secondary batteries or accumulators, which are designed and constructed for multiple charging. Charging a secondary battery represents the electrolytic reversal of the electrochemical redox reaction occurring during discharge, which is realized by applying an electrical voltage.

[0005] A battery comprises one or, usually, several battery elements arranged within an enclosure, usually in the form of a foil enclosure often referred to as a "pouch" or a housing. The battery elements each comprise two electrodes, a separator arranged between the electrodes for electrically separating the electrodes, and an electrolyte serving as an ion conductor. The two electrodes of a battery element differ in the active material they contain, whereby one of the electrodes is anodic and the other cathodic (in each case with respect to discharging the battery cell). Furthermore, a battery usually comprises two battery terminals that are integrated into the enclosure and are electrically connected to the electrodes on the inside of the enclosure via so-called current conductors.All anodic electrodes are connected to one of the battery poles and the cathodic electrodes are connected to the other of the battery poles.

[0006] A battery design with a housing can offer the advantage of higher structural strength compared to batteries with a foil coating. A battery housing is often made of a metal, particularly aluminum, to achieve sufficiently high structural strength and thus resilience while simultaneously ensuring good and cost-effective manufacturability and a relatively low weight.

[0007] Typically, during the manufacture of a battery with a housing, a composite comprising the battery element(s) is inserted into a base housing (so-called housing cup), which also has at least one housing opening, which is then closed by a housing cover. In a metal housing, the at least one cover is usually welded to the base housing. This method of battery production involves considerable effort. This is particularly true for inserting the battery element composite into the housing cup, which must be done with great precision and care to avoid damaging the sensitive components of the battery element composite.

[0008] DE 102016 121 089 A1 discloses a method for producing a cuboid-shaped battery cell container open on one side by extrusion.

[0009] DE 102013 021 398 A1 describes a battery with a housing consisting of two identically shaped housing halves.

[0010] GB 748 719 A describes a housing for a battery comprising a cup-shaped first housing part, open on one side, and a lid as the second housing part. The lid is held in the first housing part in a form-fitting manner by a circumferential projection of the lid being snapped into a corresponding recess in the first housing part.

[0011] The invention is based on the object of simplifying the production of a battery with a housing.

[0012] This object is achieved by a method according to patent claim 1. Preferred embodiments of the method according to the invention are the subject matter of the further patent claims and emerge from the following description of the invention.

[0013] According to the invention, a method is provided for producing (at least) one battery, in particular a lithium-ion battery and / or a battery intended as a traction battery of a motor vehicle and / or a solid-state battery. The battery to be produced comprises at least one battery element assembly with one battery element or, preferably, several battery elements, and a housing (completely) surrounding the battery element assembly. The housing comprises a base housing which delimits a housing interior for at least partially, preferably completely, accommodating the battery element assembly and which has a housing opening through which the battery element assembly is introduced into the housing interior, wherein the housing opening is subsequently closed with a housing cover.According to the invention, the base housing is produced by severing a blank whose shape is designed such that it encompasses the shapes of at least one or, preferably, exactly two of the base housings, which are preferably integrally connected or made of the same material. The severing can be carried out, for example, by cutting, in this case in particular by laser cutting, or by machining (e.g. by sawing). In this case, it can be provided that essentially no material waste or material loss occurs, so that the shape of the blank can then essentially correspond to the shape of the two base housings. Alternatively, it can also be provided that the blank comprises additional material or at least one additional section which is not part of the shapes of the two base housings.Particularly preferably, it can be provided that post-processing of the base housing after cutting through the blank is not required or is only required at the cutting points.

[0014] By cutting through the blank, an advantageously designed basic housing and, in particular, two identical basic housings can be obtained in a relatively simple manner, whereby an advantageous and, in particular, cost-effective manufacturability of at least one battery can be realized.

[0015] Since two identical base housings can be obtained by cutting the blank, it can advantageously be provided within the scope of a method according to the invention that the two base housings are each used to manufacture a battery according to a method according to the invention. Consequently, the manufacturing effort for the base housings can be almost halved, relative to the individual batteries.

[0016] The housing is preferably designed to be dimensionally stable. A housing is considered "dimensionally stable" if its three-dimensional shape does not collapse due to its own weight without external loading. Such a housing can preferably be designed to be dimensionally stable in such a way that it does not collapse when subjected to external forces that occur during normal battery use, and, more preferably, is not deformed to any significant extent either.

[0017] The housing can preferably be designed in such a way that it is finally sealed gas-tight, which can have a positive effect on the performance and operational reliability of the battery.

[0018] The at least one battery element of the battery element assembly of a battery to be produced according to the invention comprises (each) two electrodes, a separator arranged between the electrodes for electrically separating the electrodes, and an electrolyte serving as an ion conductor between the electrodes. This electrolyte can be liquid or solid and, particularly in a solid configuration, can also function as a separator. A battery to be produced according to the invention can further comprise a first battery terminal and a second battery terminal, wherein the battery terminals are provided for electrically connecting the battery to an external circuit.For this purpose, the battery terminals can be integrated into the housing in such a way that a first section thereof is arranged outside the housing and is thus accessible for connection to the external circuit, while a second section, located within the casing, serves for an electrical connection to the battery element or battery elements. A first electrode of (each) battery element(s) is electrically connected to the first battery terminal, and a second electrode of (each) battery element(s) is electrically connected to the second battery terminal. The battery element assembly of a battery to be produced according to the invention preferably does not itself comprise a casing and, in particular, does not comprise a (dimensionally stable) housing.

[0019] Preferably, the housing can be partially or entirely formed from at least, and preferably exactly, one metal, for example, aluminum. This allows a relatively high-strength housing to be obtained at a relatively low cost.

[0020] Preferably, it can be provided that the base housing is produced on the outside and / or inside with a cuboid shape, because a blank whose shape comprises the shapes of two cuboid base housings is comparatively easy to produce. Furthermore, a base housing and thus also a housing with a cuboid shape can advantageously be combined with a battery element assembly that also has a cuboid shape. Such a cuboid shape of the battery element assembly can result in particular from the components of the battery elements (electrodes and separators) themselves being cuboid-shaped (in particular with a relatively small thickness) and being stacked across their large sides. Furthermore, a cuboid shape of the housing enables advantageous use of the battery with regard to the required space.

[0021] A cuboid, and thus also a cuboid-shaped housing, has a length, width and height, wherein according to the invention the length is the largest, the width is the middle and the height is the smallest of the (edge) dimensions (provided that corresponding differences exist). A cuboid, and thus also a cuboid-shaped housing, then comprises two large sides spanned by the length and the width, two long sides spanned by the length and the height, and two end sides spanned by the width and height. Battery terminals of the battery can preferably be integrated into only one or both of the end sides. Advantageously, it can be provided that the housing opening is formed at least in one large side of the cuboid-shaped basic housing, wherein the housing opening particularly preferably extends substantially (i.e. with the exception of the wall thicknesses forming the long sides and end sides) over the entire large side.This allows for relatively simple insertion of the battery element assembly into the base housing. This is particularly true because it enables a relatively high pressure to be exerted on the battery element assembly only when the housing opening is closed. Such a relatively high pressure (e.g., at least 3.5 bar) can be necessary or advantageous for the functionality of the battery, particularly when the battery element or battery elements are designed with a solid electrolyte (and thus the battery is a so-called solid-state battery). When the components of the battery element or battery elements are arranged in a stack, the pressure should act in the stacking direction.

[0022] According to a preferred embodiment of a method according to the invention, it can be provided that the blank is produced with an opening or is not completely closed, whereby a relatively simple production of the blank as a hollow body can be realized. Furthermore, it can then also preferably be provided that the opening is formed on an end face of the blank having a cuboid shape, which can have an advantageous effect with regard to the manufacturability of the blank with a shape that comprises the shapes of two base housings that are connected to one another in one piece. The opening of the blank can then further preferably represent the housing opening or a section of the housing opening of the base housing or of each of the two base housings. This housing opening or the section thereof can preferably be arranged in an end face of the base housing.

[0023] According to a preferred embodiment of a method according to the invention, it can be provided that a first section of the housing opening of the base housing is first closed with a first cover part and then a second section of the housing opening is closed with a second cover part. The first section of the housing opening can particularly preferably be arranged in an end face of the base housing in a cuboid-shaped design, while the second section of the housing opening is arranged in a large side of the cuboid-shaped housing. In this case, the first cover part can preferably comprise one or more, particularly preferably all, of the battery poles of the battery, which makes it possible to electrically connect the battery poles to the battery element assembly by means of the second cover part even before the housing opening is completely closed.For this purpose, it may be provided to mechanically connect, for example, by welding, the current conductors of the battery element assembly to the battery pole or poles.

[0024] According to a preferred embodiment of a method according to the invention, the housing opening can be closed with a single, preferably one-piece cover. This can keep the manufacturing costs for the battery relatively low.

[0025] The blank used in a method according to the invention can advantageously be produced by extrusion (according to DIN 8583), in particular cold extrusion. This enables the blank to be produced in a relatively cost-effective manner using a mold that encompasses the shapes of two basic housings.

[0026] According to one embodiment of a method according to the invention, it can be provided that a deformation element is introduced into the housing interior before the housing opening is closed such that it is arranged conclusively between the battery element assembly and the housing, in particular one of the large sides of the cuboid-shaped housing. A deformation element is understood to be a component that is (primarily or exclusively) intended to compensate for different expansions of the battery element assembly on the one hand and the housing on the other hand through deformation. This makes it possible to always position the electrodes and separators within the housing without play and, at the same time, to allow a relatively large expansion of these components compared to the housing.

[0027] According to a preferred embodiment of a method according to the invention, the base housing can be manufactured with at least one contact surface for the cover to engage. This enables advantageous positioning of the cover, particularly during subsequent sealing of the cover to the base housing, which can be achieved in particular by means of a material bond, particularly preferably by welding, in particular by laser welding.

[0028] In principle, a connection of the base housing to the cover can be provided, whereby this can also be done exclusively or additionally by form-fitting and / or force-fitting.

[0029] The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. The drawings show, partly in simplified form: Fig. 1: a blank used for the production of a battery according to the invention;

[0030] Fig. 2: a section of the blank in an enlarged view;

[0031] Fig. 3: two basic housings for batteries to be produced according to the invention, which were created by cutting through the blank;

[0032] Fig. 4: one of the basic housings and a first cover part, which is used in the context of

[0033] Carrying out a method according to the invention was connected to the base housing;

[0034] Fig. 5: closing a section of a housing opening of the basic housing with a second cover part in the context of carrying out the method according to the invention;

[0035] Fig. 6: connecting a base housing with a cover in the context of

[0036] Carrying out a method according to the invention according to an alternative embodiment;

[0037] Fig. 7: connecting a base housing with a cover in the context of

[0038] Carrying out a method according to the invention according to a further alternative embodiment;

[0039] Fig. 8: one of the batteries manufactured according to the invention;

[0040] Fig. 9: a section of a blank intended for use in the manufacture of a battery according to the invention according to an alternative embodiment;

[0041] Fig. 10: a section of a basic housing for a device to be manufactured according to the invention

[0042] Battery obtained by cutting the blank according to Fig. 9;

[0043] Fig. 11: a first cover part intended for use in the manufacture of a battery according to the invention according to an alternative embodiment in a plan view;

[0044] Fig. 12: the cover part according to Fig. 11 in a side view; and Fig. 13: a battery element assembly intended for use in the manufacture of one of the batteries according to the invention.

[0045] 1 and 2 show a blank 1 which is used in the context of a method according to the invention for producing a battery. The blank has a cuboid shape with two large sides 2, two long sides 3 and two end faces 4. An opening 5 is formed in one of the end faces, which opening extends essentially over the entire end face 4, i.e. with the exception of the wall thicknesses of the walls which form the large sides 2 and the long sides 3 of the blank. On the inside, the blank 1 is provided with structures which form contact surfaces 6 against which a cover 7 can rest when the blank 1 has been severed according to the invention in the middle along the two long sides 3 and the closed end face 4 in order to form two basic housings 8, each of which is intended to be part of a housing of a battery (cf. Fig. 3).The contours are provided, on the one hand, in the form of two groove-shaped recesses 9, which run centrally in the inner walls of the longitudinal sides 3 in the longitudinal direction of the blank 1, and, on the other hand, in the form of two shoulders 10, each of which is U-shaped in the end face 4 of the blank 1, which encompasses the opening 5. The recesses 9 in the longitudinal sides 3 of the blank 1 also form shoulders 10 in the walls of the longitudinal sides 3 of the base housing 8 after cutting.

[0046] Each of the base housings 8 or a housing interior 11 formed thereby serves to accommodate a battery element assembly 12. For this purpose, the battery element assembly 12 is introduced into the housing interior 11 via a housing opening 20 of the base housing 8.

[0047] The battery element assembly 12 can comprise a plurality of battery elements according to Fig. 13. Electrodes 13 and separators 14 of the battery elements can be stacked. In this case, the battery element assembly 12 comprises, in an alternating arrangement, a plurality of first (13a) electrodes 13, which function as anodes when the battery is discharged, and a plurality of second (13b) electrodes 13, which function as cathodes when the battery is discharged. As a result of the alternating arrangement of the electrodes 13, a first electrode 13a is arranged between two second electrodes 13b and a second electrode 13b is arranged between two first electrodes 13a. Adjacent electrodes 13 are each spatially separated by one of the separators 14 and are thus also electrically insulated from one another. A first electrode 13a and a second electrode 13b, as well as a separator 14 arranged between them, form a battery element.As a result of the stacking, each of the electrodes 13, with the exception of the two outermost electrodes 13 in the stack, is functionally a component of two battery elements.

[0048] The battery elements can further comprise an electrolyte. The separators 14 can be impregnated with the liquid electrolyte. Alternatively, the separators themselves can act as a (solid) electrolyte. The electrolyte enables ions to be conducted between adjacent electrodes 13 via the separator 14 located between them.

[0049] Each of the electrodes 13 comprises a flat, foil-like substrate 15, which can be made, for example, of copper for the first electrodes 13a provided as anodes and of aluminum for the second electrodes 13b provided as cathodes. In a rectangular section thereof, the two large surfaces of each of the electrodes 13 located in the stacking direction of the battery element assembly 12 are provided with a coating of an active material 16 to enable the various electrodes 13a, 13b to function as anodes or cathodes during use of the battery. In the region of these rectangular sections of the substrates 15 and thus of the electrodes 13, these and the correspondingly rectangular-shaped separators 14 are stacked, resulting in the cuboid shape of the battery element assembly 12.

[0050] On one transverse side of the rectangular section of each electrode 13, a region of the substrate 15 is provided in which the substrate 15 is not coated with the respective active material 16. This region of the electrodes 13 serves as a current collector 17, via which the individual electrodes 13 are electrically connected to a respective associated battery terminal 18 of the battery. The current collectors 17a of all first electrodes 14a, combined as a current collector stack, are connected to a first (18a) of the battery terminals 18, and the current collectors 17b of all second electrodes 13b, also combined as a current collector stack, are connected to a second (18b) of the battery terminals 18 (see Fig. 6).

[0051] After the battery element assembly 12 and optionally also a deformation element 19 have been introduced (see Figs. 5 and 6), the housing opening 20 of the base housing 8, which extends essentially completely over a large side 2 and an end face 4 of the base housing 8, is closed by means of the cover 7. In the embodiment according to Figs. 4 and 5, this cover 7 comprises two separate, completely planar or flat-shaped cover parts 7a, 7b, whereas in the embodiment according to Figs. 6 to 8, a one-piece, angled cover 7 with an L-shaped cut contour in longitudinal section is used. In the embodiment according to Figs. 4 and 5, a first cover part 7a, which covers the section of the housing opening 20 located in the end face 4 of the base housing 8, is first positioned and fixed against the contact surfaces 6 of the base housing 8 there.The first cover part 7a can be temporarily or finally bonded to the base housing 8. According to Fig. 4, the first housing part 7a can be attached to the base housing 8 even before the battery element assembly 12 has been inserted into the housing interior 11 of the base housing 8. Alternatively, the battery element assembly 12 can be inserted into the housing interior 11 first, and only then can the first cover part 7a be connected to the base housing 8.

[0052] The battery element assembly 12 can advantageously be inserted into the housing interior 11 via, or perpendicular to, the section of the housing opening 20 located in one of the large sides 2 of the base housing 8, thereby requiring only a relatively short relative movement between these components. This allows for a relatively simple insertion of the battery element assembly 12 into the housing interior 11, while also minimizing the risk of damage to the components of the battery element assembly 12.

[0053] Another significant advantage of inserting the battery element assembly 12 via the section of the housing opening 20 formed in one large side 2 of the base housing 8, which simplifies the assembly of the battery, is that a relatively high pressure is exerted on the battery element assembly 12 (in the stacking direction of the components of the battery element assembly 12) only upon subsequent application of the cover 7 or the second cover part 7b. Such a relatively high pressure can be advantageous or necessary for operation, particularly when the battery element assembly 12 is configured with a solid electrolyte.

[0054] The first cover part 7a in the battery to be manufactured according to Figs. 4 and 5 or the corresponding section of the cover 7 in the batteries to be manufactured according to Figs. 6 and 7 comprises the two battery poles 18 of the respective battery, which are integrated into the cover (part) 7, 7a in such a way that a connection section thereof is accessible on both sides of the cover (part) 7, 7a in order to connect the battery poles 18, on the one hand, to the current collectors 17 and thus to the electrodes 13 of the battery element assembly 12, and on the other hand, to be able to contact the battery 1 externally. At least one of the battery poles 18 is electrically insulated from the housing. The connection of the battery poles 18 to the current collectors 17 can, in principle, be made in any desired manner, i.e.For example, before or after the battery element assembly 12 has been introduced into the base housing 8 and the cover (part) 7, 7a has been attached thereto, or after the battery element assembly 12 has been introduced into the base housing 8, but the cover (part) 7, 7a has not yet been attached. Furthermore, the connection of the battery poles 18 to the current conductors 17 in the battery to be manufactured according to Figs. 4 and 5 can take place after the first cover part 7a has been attached to the base housing 8, but the battery element assembly 12 has not yet been inserted into the base housing 8.

[0055] The housing opening 20 of the base housing 8 is then completely closed with the cover 7 of the housing. In the battery to be manufactured according to Figs. 4 and 5, the second cover part 7b is attached to the base housing 8 for this purpose, wherein said second cover part 7b rests against the corresponding contact surfaces 6 which extend in the longitudinal direction of the base housing 8. In the battery to be manufactured according to Fig. 6, in contrast, the entire cover 7 is pivoted (exclusively) around the free edge of the front section of the cover 7 until the cover 7 rests completely against the contact surfaces 6 of the base housing 8. In the battery to be manufactured according to Fig. 7, in contrast, the cover 7 is attached in an exclusively translational movement relative to the base housing 8. A combination of rotational and translational movement of the cover 7 is also possible and may be advantageous.

[0056] In a final process step, the cover 7 is integrally joined to the base housing 8, if not already done. This can advantageously be done by laser welding. The battery to be manufactured according to Figs. 4 and 5 has the advantage that the two weld seams to be made to connect the two cover parts 7a, 7b are each located in a single plane, so that the laser only needs to be moved two-dimensionally for welding. For the batteries to be manufactured according to Figs. 6 and 7, however, a three-dimensional movement of the laser may be necessary, which results from the angled shape of the respective cover 7.

[0057] Fig. 9 shows an alternative embodiment of a blank 1 for use in the production of a battery according to the invention. This blank 1 differs from the one according to Figs. 1 and 2 in that the recesses 9, which run centrally on the inside in the walls of the long sides 3 in the longitudinal direction of the blank 1, are supplemented by a further recess 9, which is formed centrally on the inside in the wall of the closed end face 4 of the blank 1 and which merges into the long side recesses 9. As a result, each of the two base housings 8, which are obtained by severing the blank 1, has an additional contact surface 6, which is formed as a shoulder in the end wall there (cf. Fig. 10).

[0058] Figs. 11 and 12 show an alternative embodiment of a first cover part 7a which can be used in the manufacture of a battery according to Figs. 4 and 5.

[0059] Compared to the first cover part 7a, as shown in Figs. 4 and 5, the first cover part 7a according to Figs. 11 and 12 has a shoulder 10, which in turn forms a contact surface 6 against which the second cover part 7b rests after attachment.

[0060] LIST OF REFERENCE SYMBOLS

[0061] blank

[0062] Large side of a cuboid Long side of a cuboid End face of a cuboid Opening of the blank Contact surface Lid a first lid part b second lid part

[0063] Basic housing

[0064] Recess 0 Paragraph 1 Housing interior 2 Battery element assembly 3 Electrode 3a First electrode 3b Second electrode 4 Separator 5 Electrode substrate 6 Active material of the electrode 7 Current collector 7a First current collector 7b Second current collector 8 Battery terminal 8a First battery terminal 8b Second battery terminal 9 Deformation element 0 Housing opening

Claims

PATENT CLAIMS Method for producing a battery which has a battery element assembly (12) with at least one battery element and a housing surrounding the battery element assembly (12), wherein the housing comprises a base housing (8) which delimits a housing interior (11) for at least partially receiving the battery element assembly (12) and which has a housing opening (20) through which the battery element assembly (12) is introduced into the housing interior (11), wherein the housing opening (20) is subsequently closed with a cover (7) of the housing, characterized in that the base housing (8) is produced by severing a blank (1), the shape of which is designed such that it comprises the shapes of two of the base housings (8). Method according to claim 1, characterized in that the base housing (8) is produced on the outside and / or inside with a cuboid shape.Method according to claim 2, characterized in that the housing opening (20) is formed at least also in one large side of the cuboid-shaped base housing (8). Method according to one of the preceding claims, characterized in that the blank (1) is produced with an opening (5). Method according to claim 4, characterized in that the opening (5) is arranged on an end face of the cuboid-shaped blank (1). Method according to one of the preceding claims, characterized in that the blank (1) is produced by extrusion. Method according to one of the preceding claims, characterized in that a first section of the housing opening (20) is first closed with a first cover part (7a) and then a second section of the housing opening (20) is closed with a second cover part (7b).Method according to claim 7, characterized in that the first cover part (7a) comprises at least one battery terminal (18). Method according to one of claims 1 to 6, characterized in that the housing opening (20) is closed with a single cover (7). Method according to one of the preceding claims, characterized in that a deformation element (19) is introduced into the housing interior (11) before the housing opening (20) is closed in such a way that it is subsequently arranged between the battery element assembly (12) and the housing. Method according to one of the preceding claims, characterized in that the base housing (8) is produced with at least one contact surface (6) for the contact of the cover (7). Method according to one of the preceding claims, characterized in that the base housing (8) and the cover (7) are connected to one another by a material fit. Method according to one of the preceding claims for producing two batteries, characterized in that by severing the blank (1), two base housings (8) are obtained, each of which is used to produce a battery.

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