DE102012212256A1 - Battery cell comprises cell housing, electrode disposed in inner region of housing, and electrolyte material provided between housing and electrode, where cell housing includes cap assembly having housing cover and two battery contacts - Google Patents

Abstract

The battery cell comprises a cell housing, an electrode disposed in an inner region of the housing, and an electrolyte material provided between the housing and the electrode. The cell housing includes a cap assembly having a housing cover and two battery contacts for electrically contacting the battery cell. The battery contact comprises a current collector arranged in an inner region of the cell housing, and a battery terminal arranged in an outer region of the cell housing. The current collector has a recess, and is electrically coupled to the electrode. The battery cell comprises a cell housing, an electrode disposed in an inner region of the housing, and an electrolyte material provided between the housing and the electrode. The cell housing includes a cap assembly having a housing cover and two battery contacts for electrically contacting the battery cell. The battery contact comprises a current collector arranged in an inner region of the cell housing, and a battery terminal arranged in an outer region of the cell housing. The current collector has a recess, and is electrically coupled to the electrode. A portion of the battery terminal is guided through the recess of the current conductor. A welded joint is formed an inner surface of the recess to connect the battery connector with the current collector. Each of the battery contacts comprises two welds (16). The battery contact comprises a cylindrical or conical section facing the inner region of the cell housing. The battery contact further comprises a first and a second connection part (32, 34) made from different materials. The second connection part is connected to current collector. A gasket is arranged between the battery contact and housing cover. An independent claim is included for a method for manufacturing a lid arrangement for battery cell.

Description

The present invention relates to a battery cell having a cell case, two electrodes forming a cathode and an anode disposed in an inner portion of the cell case, and an electrolyte material disposed in the inner portion of the cell case surrounding the electrodes, the cell case a lid assembly having a housing cover and two battery contacts for electrically contacting the battery cell.

Furthermore, the present invention relates to a method for producing a cover assembly for a cell housing of a battery cell, wherein the battery cell has two electrodes, which are arranged in an inner region of the cell housing, and an electrolyte material, which is arranged in the inner region of the cell housing and surrounding the electrodes ,

State of the art

A battery is an electrochemical energy store and an energy converter. As the battery discharges, stored chemical energy is converted to electrical energy by an electrochemical reaction. The electrical energy can be used by a consumer that is electrically coupled to the battery. In principle, batteries are differentiated between primary and secondary batteries. Primary batteries can only be discharged once and not recharged. In contrast, the secondary batteries are rechargeable. In the following, the term "battery" or "battery cell" is used as a synonym for the secondary battery or secondary cell.

In motor vehicles, a battery is used, among other things, to supply power to the headlights, the on-board electronics and the starter for starting the internal combustion engine. In electric or hybrid vehicles, the battery additionally serves as an energy store for the electric drive of the motor vehicle. It thus determines significantly the performance and range of the vehicle.

The batteries used in motor vehicles (for example lithium-ion batteries) often have a prismatic shape for reasons of volumetric efficiency. Inside the case is a flat-pressed coil, which is rolled out of an aluminum foil, a copper foil, as well as two plastic foils serving as diaphragms. The aluminum foil and the copper foil are coated with reactive cathode and anode materials. The battery housing is filled with a liquid electrolyte after inserting the coil and before the pressure-tight closure.

The cathode and anode foil of the coil are not precisely matched, but slightly offset one above the other to allow electrical contact between the two films. The contacting of the projecting foil strips takes place with welded strip-shaped sheet metal parts made of copper and / or aluminum, the so-called current collectors. When contacting the above-mentioned current collectors in the interior of the battery case and when carrying out the current paths through the housing in an outer area of the battery cell, various aspects must be considered. Thus, the current paths must first be electrically insulated from the metallic housing. Furthermore, the tightness of the current feed through the housing must be ensured. This refers in particular to the discharge of pressurized, liquid electrolyte. In addition, there is the requirement to be able to apply mechanical loads, in particular transverse forces and bending moments, from the outside to the battery contacts.

To cover these requirements, a plurality of components is used in known battery cells, which produce the electrical contact with the arranged inside the battery cell electrodes. For this purpose, the components are connected to each other by means of a complex combination of rivet, laser welding and friction welding. Usually, the welded connections are arranged on an inner side and an outer side of a housing cover of the cell housing. Changes to the construction of the housing cover are therefore difficult to implement. Due to the large number of components used and the associated rivet, laser welding and Reibschweißverbindungen also has a high sensitivity to errors. Thus, for example, electrolyte material can escape from the battery cell or else the electrical contact with the electrodes can be interrupted. Furthermore, lateral forces can be better absorbed.

Disclosure of the invention

The present invention therefore provides a battery cell having a cell case, two electrodes disposed in an inner portion of the cell case, and an electrolyte material disposed in the inner portion of the cell case surrounding the electrodes, the cell case having a lid assembly with a case lid and two battery contacts for electrically contacting the battery cell, each of the battery contacts having a current collector arranged in the inner region of the cell housing, which has a recess and is electrically coupled to one of the electrodes, and has a battery terminal arranged at least partially in an outer region of the cell housing one each Section of the battery terminal is guided through the recess of the current collector, wherein on an inner surface of the recess in each case a welded connection is formed to connect the battery terminal with the current collector.

Further, the present invention provides a method for manufacturing a lid assembly for a cell case, a battery cell, the battery cell having two electrodes disposed in an inner portion of the cell case and an electrolyte material disposed in the inner portion of the cell case and surrounding the electrodes. wherein initially a housing cover is provided having an outer side and an inner side, wherein a battery terminal for electrically contacting the battery cell is provided, wherein the battery terminal is inserted into an opening of the housing cover from the outside, so that a first end of the battery terminal the outer side protrudes and a second end of the battery terminal protrudes on the inside, wherein a current collector is provided, which has a recess and is electrically coupled to one of the electrodes, wherein the current collector at the second end de s battery terminal is mounted from the inside of the housing cover, so that the recess of the current collector at least partially surrounds the second end of the battery terminal, and wherein the current collector and the battery terminal are connected by means of a welded connection, which is formed on an inner surface of the recess.

Advantages of the invention

In the battery cell according to the invention only a few components for the electrical contacting of the electrodes are needed. Thus, each of the battery contacts according to the invention has only one battery connection and one current collector, which are connected via a welded connection. Due to the lower complexity of the battery contacts, any necessary changes to the design of the battery contacts can be made easier. In addition, the smaller number of components leads to reduced costs and a reduced susceptibility to failure of the battery cell.

In addition, the components of the battery contacts are mounted in known battery cells in a direction from an inner side of the housing cover to an outer side of the housing cover and repeatedly welded together.

In contrast, the machining direction is reversed in the manufacture of the lid assembly according to the invention. According to the inventive method, the components of the battery contacts (battery terminal, current conductor) are mounted in a direction from an outer side of the housing cover to an inner side of the housing cover. Subsequently, the components are welded together from the inside of the housing cover. This reversal of the machining direction is technically feasible since the manufacture of the cover assembly is carried out as an upstream process for the complete assembly of the battery cell. The applied method thus leads to a simple and cost-effective installation of the components of the battery contacts.

In this case, the battery terminal and the current conductor, which are used for contacting the positive electrode, for example made of aluminum. By contrast, the components (battery connection, current conductor) for contacting the negative electrode are made of copper, for example. By using the same materials for the respective battery connection and current collector, the components can be reliably connected to one another in a simple manner.

In a preferred embodiment, each of the battery contacts has a maximum of two welded joints.

Due to the small number of components that are used for the battery contact according to the invention, a maximum of two welded joints are required to make the battery contact. This leads to increased mechanical stability and greater reliability of the battery cell. Furthermore, the battery cell can be made simpler and therefore cheaper.

In a further embodiment, the battery connection has a conical section on its end facing the inner region of the cell housing.

The conical section, which tapers towards the end of the battery connection, allows the current collector to be simply pressed onto the battery connection. This additionally increases the mechanical stability of the connection between the current conductor and the battery connection.

In an alternative embodiment, the battery connection has a cylindrical section at its end facing the inner region of the cell housing.

According to a further embodiment, the battery connection has a first and a second connection part, which are made of different materials, wherein the second connection part is connected by means of the welded connection to the current conductor, and wherein the first and the second connection part are connected by means of a second welded connection.

By way of example, the first connection part can be made of aluminum and the second connection part can be made of copper. This embodiment of the battery contacts is used, for example, for contacting the negative electrode. Since the current arrester coupled to the negative electrode is usually made of copper, the welded connection between the current conductor and the second terminal part of the battery terminal can be carried out on identical materials. This leads to a reliable welded connection between these components.

In a further embodiment, the current conductor is a bent sheet metal part.

Bending allows the current arrester to be easily manufactured.

According to a further embodiment, a sealing ring is arranged between the battery connection and the housing cover.

The sealing ring ensures that even a pressurized electrolyte material can not escape from the cell housing. In addition, the sealing ring assumes an insulation function. The sealing ring thus isolates the current-carrying battery connection against the cell housing. In addition, the sealing ring is used for the absorption of transverse forces, which are exerted on the battery contacts from the outside.

According to a preferred embodiment of the method according to the invention, the battery terminal and the current conductor are manufactured in such a way that a press fit is formed when the current conductor is attached to the battery terminal.

Due to the interference fit, the current conductor is fixed to the battery connection. Subsequently, the interference fit is additionally secured by the welded joint. This results in a very stable connection between the current conductor and the battery connection. This reduces the sensitivity of the battery contacts to mechanical loads or forces. This leads to a high reliability of the battery cell produced according to the invention.

According to a further embodiment of the method, the current conductor and the battery terminal are connected by laser welding.

The laser welding process creates a reliable and durable connection between the current collector and the battery connector. The laser welding process is carried out at a very high speed and high power in order not to damage a sealing element / a sealing ring, which is arranged for example between the battery connection and the housing cover, by an excessive thermal load. In this case, using the laser welding preferably components with the same material materials are connected to each other (for example, aluminum-aluminum, copper-copper). However, it is also possible to connect components made of different materials (for example, aluminum-copper) by laser welding.

In a further embodiment of the method, the battery connection is produced by extrusion.

In extrusion molding, by simply changing the extrusion die, different terminal geometries of the battery terminal can be made (eg, thread, tenon, quadrilateral). This allows the use of different technologies for contacting the battery cells with each other or for connecting a consumer to the battery cell (for example, screws, welding, clamps).

According to a further embodiment of the method, the provision of the battery connection comprises the provision of a first and second connection part and a connection of the first connection part and the second connection part by means of a second welded connection.

By dividing the battery connection into a first and second connection part different materials for the two connection parts can be used. In particular, it can thus be ensured that the same materials are connected to one another in the laser welding process between the battery terminal and the current conductor. If, for example, the current conductor is designed to make contact with the negative electrode in copper, then the second terminal part of the battery terminal can also be made in copper in order to enable a similar laser welding connection. For the first connection part of the battery connection, for example aluminum can be selected in this embodiment. This measure therefore leads to increased flexibility in the choice of material for the battery connection.

In a further embodiment of the method, the first connection part and the second connection part are connected by friction welding.

By friction welding, for example, the first connection part in aluminum and the second connector part are made in copper. Thus, the subsequent laser welding connection can be performed on similar materials. By means of the friction-welded connection, a reliable connection is made between the first and the second connection part. This leads to a high mechanical stability of the battery contact according to the invention.

Alternatively, ultrasonic welding can also be used.

It is understood that the features, properties and advantages of the device according to the invention also apply or can be applied correspondingly to the method according to the invention.

Brief description of the drawings

1 shows in schematic form an embodiment of a cover assembly according to the invention for a cell housing of a battery cell;

2 shows several embodiments of a battery terminal according to the invention for contacting a positive electrode of the battery cell;

3 shows several embodiments of a battery terminal according to the invention for contacting a negative electrode of the battery cell; and

4 shows a diagram for explaining an embodiment of a method according to the invention.

Embodiments of the invention

In 1 is in schematic form an embodiment of a lid assembly according to the invention 10 for a cell housing 12 one in 1 unspecified battery cell shown. The cell case 12 has an in 1 only hinted housing container 14 in which, for example, a positive electrode, a negative electrode and an electrolyte material are arranged. In a mounted state of the battery cell is the lid assembly 10 by means of welds 16 with the housing container 14 connected. The cell case 12 is thus closed.

The lid arrangement 10 has a housing cover 18 and two battery contacts 20 for electrically contacting the battery cell. Here is the battery contact 20a in a mounted state of the battery cell with the positive electrode and the battery contact 20b electrically coupled to the negative electrode of the battery cell.

The cell case 12 is at the bushings of the battery contacts 20 through the housing cover 18 using sealing elements / sealing rings 22 sealed. Thus, for example, prevents electrolyte material from the cell housing 12 exit. In addition, the battery contacts 20 using the sealing rings 22 opposite the housing cover 18 electrically isolated. Furthermore, the sealing rings serve 22 for receiving mechanical loads, for example, from an outside of the cell housing 12 on the battery contacts 20 be exercised.

Each of the battery contacts 20 has one in an interior of the cell housing 12 arranged current conductor 24 and at least partially in the exterior of the cell housing 12 arranged battery connection 26 on. The current collector 24a is electrically coupled to the positive electrode in a mounted state of the battery cell. Analogous is the current conductor 24b electrically coupled to the negative electrode of the battery cell. The current collector 24 are preferably designed as sheet metal parts. Here is the current conductor 24a for example, aluminum and the current conductor 24b made of copper.

The current collector 24 each have a recess 28 into which the associated battery connection 26 is introduced. On an inner surface of the recess 28 is in each case a laser welding connection 30 formed around the battery connector 26 with the current collector 24 connect to.

In this embodiment, assume that the battery terminal 26a made of aluminum. As is the current collector 24a Made of aluminum, the laser weld joint 30a between two components (current conductor 24a , Battery connection 26a ), which have the same materials are executed. A laser welding connection for dissimilar materials is possible, but the laser welding process is preferably used for the connection of similar materials. For example, if an external contact of the battery terminal 26b be made in aluminum, so there is the possibility of the battery connection 26b form as a two-part battery connection. This indicates the battery connection 26b a first connection part 32 and a second connection part 34 on. The first connection part 32 is then for example made of aluminum and the second connection part 34 made of copper. The first connection part 32 is by means of a friction-welded connection 36 with the second connection part 34 connected. Due to this construction of the battery connection 26b can the laser welding connection 30b that the current conductor 24b and the second connection part 34 connecting with each other, be carried out for similar materials.

From the above-described construction of the lid assembly 10 It can be seen that only very few components for contacting the electrodes of the battery cell are necessary. As a result, the battery contact 20a For example, only one laser welding connection 30a on. Also the battery contact 20b only has the laser welding connection 30b and the friction-welded connection 36 on. Due to the maximum of two welded joints, for each of the battery contacts 20 are needed, a high mechanical stability of the battery contacts 20 reached. The reliability of the battery cell is increased.

By the inventive arrangement of the welds 30 . 36 becomes a very simple assembly of the lid assembly 10 allows. This can reduce the cost of manufacturing the battery cell. Because the welds 30 . 36 on an inside of the lid assembly 10 can be arranged, design changes for the lid assembly 10 be implemented more easily. This increases the flexibility in the design of the lid assembly 10 ,

2 shows several embodiments of the battery connector 26a for contacting the positive electrode of the battery cell. The battery connection 26a is preferably produced by extrusion. This can be realized by changing the extrusion tool different connection geometries. For example, the battery connector 26a provided with a thread or a pin or in square shape. This allows the use of different technologies for contacting the battery cells with each other or for contacting a consumer. For example, it is possible to make contact via screwing, welding or clamping.

In addition, the battery connection 26a and the current collector 24a preferably made so that when plugging the Stromableiters 24a on the battery connection 26a forms a press fit. This is indicated by the battery connection 26a advantageously a conical section 38a on. This can be achieved by simply pressing on the current conductor 24a on the battery connection 26a a good fixation or pre-fixation between these two components can be achieved.

3 shows several embodiments of the battery terminal according to the invention 26b for contacting the negative electrode of the battery cell. Analogous to the battery connection 26a also becomes the battery connection 26b preferably produced by extrusion, in order to realize different connection geometries. Unlike the battery connection 26a is the battery connection 26b either in one piece or in two parts (first connection part 32 , second connection part 34 ).

In the two-part embodiment, the first connection part 32 and the second connection part 34 by means of friction welding connection 36 connected. The two-part embodiment allows flexible adaptation of the materials of the first connection part 32 and the second connector 34 to the respective requirements. For example, the material and the connection geometry of the first connection part 32 be selected depending on the desired connection technology for contacting an external consumer. By contrast, the material selection is based on the second connection part 34 on the type of connection to the current conductor 24b , In one embodiment, the second connector part 34 made of copper. Is the current conductor 24b also made of copper, so the laser welding connection 30b be carried out between similar materials. As material for the first connection part 32 For example, aluminum can be chosen.

Analogous to the battery connection 26a also indicates the battery connection 26b a conical section 38b on to when pressing the current conductor 24b on the battery connection 26b To obtain a good mechanical fixation between these two components.

In 4 is a diagram for explaining an embodiment of a method according to the invention 40 shown. The procedure 40 serves for producing the lid assembly 10 that form part of the cell housing 12 forms the battery cell. The manufacture of the lid assembly 10 is preferably carried out as a pre-process to the final assembly of the battery cell, wherein the lid assembly 10 over the welds 16 with the housing container 14 is connected.

In a first step 42 First, the housing cover 18 and the battery connections 26 provided. In this embodiment, the battery terminal is 26a in one piece and the battery connection 26b executed in two parts. For making the battery connection 26b first becomes the first connection part 32 and the second connection part 34 provided. Subsequently, the first connection part 32 and the second connection part 34 by means of friction welding connection 36 connected. This will be the battery connection 26a and the first connection part 32 made of aluminum and the second connection part 34 made of copper.

In addition, in the first step 42 of the procedure 40 the current conductors 24 provided. The current collector 24a For example, it is made of aluminum and the current conductor 24b made of copper. Preferably, the battery connections 26 produced by extrusion.

In one step 44 become the battery connections 26 including the sealing rings 22 from an outside into corresponding openings of the housing cover 18 introduced. In each case, a first end of the battery connections protrudes 26 on the outside and a second end of the battery connections 26 on an inside of the housing cover 18 out.

In a further step 46 become the current conductors 24 from the inside of the housing cover 18 on the conical section 38 the respective battery connections 26 pressed. This surrounds the recesses 28 the current conductor 24 the second end of the respective associated battery terminals 26 ,

In one step 48 become the current conductors 24 and the battery connections 26 by means of laser welding connections 30 connected to create a reliable and durable connection between these components. The laser welding process is carried out at a high speed and high power around the inner sealing rings 22 thermally harmless.

In the production method according to the invention 40 becomes the mounting order / machining direction in the assembly of the lid assembly 10 vice versa compared to known methods. Thus, in known methods, the individual components are mounted from an inner side of a housing cover to an outer side of the housing cover and welded together.

According to the method of the invention 40 become the components of the battery contacts 20 from the outside of the housing cover 18 to the inside of the housing cover 18 assembled. Subsequently, the current conductors 24 and the battery connections 26 welded from the inside. This is technically feasible, since the assembly of the lid assembly 10 is executed as a pre-process.

Using the method according to the invention 40 may be the number of components and the associated complexity of the lid assembly 10 be reduced. This eventually leads to a low error sensitivity of the battery cell.

Although thus a preferred embodiment of the manufacturing method according to the invention 40 and a cover assembly thus produced 10 It has been shown that various modifications and changes can be made without departing from the scope of the invention.

For example, both battery connections 26 be made in one piece or two parts.

In addition, for the battery connections 26 Any other materials are used.

Claims (14)

Battery cell, comprising: - a cell housing ( 12 ), Two electrodes located in an inner area of the cell housing ( 12 ) are arranged, and - an electrolyte material, which in the interior of the cell housing ( 12 ) and surrounds the electrodes, wherein the cell housing ( 12 ) a lid assembly ( 10 ) with a housing cover ( 18 ) and two battery contacts ( 20 ) for electrically contacting the battery cell, each of the battery contacts ( 20 ) one in the interior of the cell housing ( 12 ) arranged current conductor ( 24 ), which has a recess ( 28 ) and is electrically coupled to one of the electrodes, and at least partially in an outer region of the cell housing ( 12 ) arranged battery connection ( 26 ), wherein in each case a portion of the battery terminal ( 26 ) through the recess ( 28 ) of the current conductor ( 24 ) is guided, wherein on an inner surface of the recess ( 28 ) each have a welded connection ( 30 ) is formed around the battery connector ( 26 ) with the current conductor ( 24 ) connect to. A battery cell according to claim 1, wherein each of the battery contacts ( 20 ) a maximum of two welded joints ( 30 . 36 ) having. Battery cell according to claim 1 or 2, wherein the battery connection ( 26 ) at its inner area of the cell housing ( 12 ) facing end has a cylindrical portion. Battery cell according to claim 1 or 2, wherein the battery connection ( 26 ) at its inner area of the cell housing ( 12 ) end facing a conical section ( 38 ) having. Battery cell according to one of claims 1 to 4, wherein the battery connection ( 26 ) a first and a second connector part ( 32 . 34 ), which are made of different materials, wherein the second connecting part ( 34 ) by means of the welded connection ( 30 ) with the current conductor ( 24 ), and wherein the first and the second Connection part ( 32 . 34 )) by means of a second welded joint ( 36 ) are connected. Battery cell according to one of claims 1 to 5, wherein the current conductor ( 24 ) is a bent sheet metal part. Battery cell according to one of claims 1 to 6, wherein between the battery terminal ( 26 ) and the housing cover ( 18 ) a sealing ring ( 22 ) is arranged. Procedure ( 40 ) for producing a cover assembly ( 10 ) for a cell housing ( 12 ) of a battery cell, wherein the battery cell has two electrodes which are located in an inner region of the cell housing ( 12 ) are arranged, and an electrolyte material, which in the interior of the cell housing ( 12 ) and surrounding the electrodes, wherein the method ( 40 ) comprises the steps: - providing a housing cover ( 18 ) having an outer side and an inner side, - providing a battery connection ( 26 ) for electrical contacting of the battery cell, - insertion of the battery connection ( 26 ) in an opening of the housing cover ( 18 ) from the outside so that a first end of the battery connector ( 26 ) protrudes on the outside and that a second end of the battery connector ( 26 ) protrudes on the inside, - providing a current conductor ( 24 ), which has a recess ( 28 ) and can be electrically coupled to one of the electrodes, - attaching the current conductor ( 24 ) at the second end of the battery connector ( 26 ) from the inside of the housing cover ( 18 ), so that the recess ( 28 ) of the current conductor ( 24 ) the second end of the battery connector ( 26 ) at least partially surrounds, and - connecting the Stromableiters ( 24 ) and the battery connection ( 26 ) by means of a welded connection ( 30 ), which on an inner surface of the recess ( 28 ) is formed. Method according to claim 8, wherein the battery connection ( 26 ) and the current conductor ( 24 ) are manufactured so that when attaching the current conductor ( 24 ) on the battery connector ( 26 ) forms a press fit. Method according to claim 8 or 9, wherein the current conductor ( 24 ) and the battery connector ( 26 ) are connected by laser welding. Method according to one of claims 8 to 10, wherein the battery connection ( 26 ) is produced by extrusion. Method according to one of claims 8 to 11, wherein the provision of the battery connection ( 26 ) comprises the following steps: - providing a first and second connection part ( 32 . 34 )), and - connecting the first connection part ( 32 ) and the second connection part ( 34 ) by means of a second welded connection ( 36 ). Method according to claim 12, wherein the first connection part ( 32 ) and the second connection part ( 34 ) are connected by friction welding. Method according to claim 12, wherein the first connection part ( 32 ) and the second connection part ( 34 ) are connected by ultrasonic welding.

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