DE102022200514A1 - Battery cell assembly for a high-voltage battery system - Google Patents

Abstract

The invention relates to a battery cell assembly, with battery cells (1) stacked one behind the other in a stacking direction (x), which have cathode conductors (3) and anode conductors (5) aligned in the transverse direction (y) of the stack, the cathode conductors (3) and the anode conductors (5) of the battery cells (1) being electrically connected to one another by means of a busbar system (6) according to a predetermined wiring diagram (Vsoll). According to the invention, the battery cell assembly is assigned an external activation device (37) with which switching units (pin) can be activated in the busbar system (6) depending on the wiring scheme (Vsetpoint) to be set, in order to define the wiring scheme (Vsetpoint) in the battery cell assembly.

Description

The invention relates to a battery cell assembly for a high-voltage battery system according to the preamble of claim 1 and a method for producing such a battery cell assembly according to claim 10.

In common practice, a busbar is understood to mean a component that is welded to the arrester of a battery cell. With the help of busbars, the battery cells in a battery cell group are electrically connected to one another in parallel and/or series connection in a specific connection scheme. The busbar is usually designed as a hybrid component consisting of plastic and at least one metal part. Depending on the desired parallel or series connection, the metal part (mainly a nickel-tin alloy) of the busbar is placed on a plastic body. After the metal part has been welded to the respective arrester of the battery cells, the result is a battery cell assembly, such as a battery module, in which the cells are connected in the desired parallel and series circuit.

A generic battery cell assembly consists of battery cells stacked one behind the other in a stacking direction. These have cathode conductors and anode conductors transverse to the stacking direction. The cathode collectors and the anode collectors of the battery cells are electrically connected to one another by means of a busbar system according to a predetermined wiring diagram.

In the prior art, the battery cell stack is not flexible enough to easily adapt to new parallel and series configurations. If, for example, there are twelve pouch or prismatic cells and the module is to be switched from one wiring scheme (e.g. 3P4S) to another wiring scheme (e.g. 2P6S), the extensive changes described below must be made. This is time consuming, expensive and error prone.

The cells are grouped differently for different wiring schemes (e.g. 3P and 2P). In a 3P wiring scheme, for example, three aluminum arresters (positive), then three copper arresters (negative), then three aluminum arresters and then three copper collectors are arranged on one side of the battery cell stack. With a 2P wiring scheme, on the other hand, the order can be as follows: two aluminum arresters - two copper arresters, two aluminum arresters - two copper arresters - two aluminum arresters - two copper arresters. If the cells are not stacked correctly, the module must be scrapped. The above conversion from 3P to 2P requires extensive software intervention, needs to change the visual inspection, and finally needs to adjust the hardware as well. Therefore, a battery cell stack usually consists of a fixed parallel and series combination that cannot be changed. This means that each time a new parallel and series combination is required, a separate line of modules is required. This increases the cost of the module development line immensely.

In addition, the following situation arises in the state: The busbar is connected to the arrester in such a way that the cells are arranged in parallel and in series. The busbars have corresponding grooves in the metal plate of the busbar. This means that a separate busbar is required for each new parallel and series connection. This requires a high level of inventory and the chance of picking the wrong busbars is high. It is also important that the busbars are used correctly, otherwise the module will have to be scrapped. Not only does this mean that you need a high inventory of different busbars for each parallel and series combination, but also that you have to check that the busbars are placed correctly and that the right pair of busbars has been selected.

The metallic part of a busbar known from the prior art also consists of a nickel-tin alloy. This offers good corrosion resistance compared to copper. However, for an aluminum arrester, it would be better to use an aluminum alloy material. Because aluminum can be welded to aluminum sheet. Since the metal part has to connect both the copper and the aluminum conductor, it is not possible to use different metal plates. Current busbar metal plate is not optimal in terms of weldability and corrosion resistance.

From the WO 2019/060047 A1 and from the WO 2016/053415 A1 different busbar systems for a battery cell assembly are known.

The object of the invention is to provide a battery cell assembly for a high-voltage battery system that allows a greater degree of freedom compared to the prior art with regard to the electrical connection of the battery cells.

The object is achieved by the features of claim 1 and claim 10. Preferred developments of the invention are disclosed in the dependent claims.

The battery cell assembly according to the invention consists of a number of battery cells stacked one behind the other in a stacking direction. These have cathode conductors and anode conductors transverse to the stacking direction. The cathode collectors and the anode collectors of the battery cells are electrically connected to one another according to a predefined wiring diagram and connected to a positive cell assembly terminal and a negative cell assembly terminal. In the battery cell assembly, all of the cathode conductors can be grouped on a cathode side of the battery cell assembly, while all of the anode conductors can be grouped on an anode side of the battery cell assembly that is opposite the cathode side across the stacking direction. In this way, a stacking error when assembling the battery cell assembly can be avoided, in which case the alignment of the cathode and anode conductors cannot be brought into line with the wiring diagram in the battery cell assembly due to an incorrectly stacked battery cell. According to the invention, on the other hand, the battery cells are always stacked in the same orientation, regardless of the desired wiring scheme in the battery cell assembly, so that stacking errors due to incorrectly stacked battery cells can be avoided.

According to the characterizing part of claim 1, an external activation device is assigned to the battery cell assembly to define the wiring diagram. With the activation device, switching units in the busbar system can be activated depending on the desired wiring scheme to be set, in order to define the wiring scheme in the battery cell assembly. For example, during a battery cell assembly manufacturing process, the switching units located in the battery cell assembly can remain in their blocked position, that is to say deactivated, so that no wiring diagram has yet been defined. Only at the end of the production process can an activation step take place, in which a target interconnection scheme can be set using the activation device. According to the invention, a busbar system can therefore be provided independently of the wiring scheme, with which the manufacturing process of the battery cell assembly can be made more flexible. After the activation step has been completed, the activation device can be removed from the busbar system of the battery cell assembly.

According to the invention, regardless of the intended parallel and series connection, all cells can be arranged in such a way that all anode current conductors are located one above the other. Likewise, all cathode current collectors are on top of each other. On the other hand, there are no aluminum and copper current collectors that alternate on top of each other. This avoids errors when assembling the cells one on top of the other. This also makes it easier to assemble the cells in the module. A compression pad can follow after every three cells. It is also possible to add a compression pad after each cell. This means that the anode side of the cell stack has only negative current collectors (copper) and the cathode side of the cell stack has only positive current collectors (aluminum).

Furthermore, according to the invention, the anode-side busbar and the cathode-side busbar can be designed identically and have grooves or slots into which the current conductors are welded. Only the slots are metal and embedded in a plastic cover. It is important that each slot is electrically isolated from the others. Therefore, the cathode and anode busbars according to the invention do not have a metal plate as in conventional busbars, but only metal inserts with slots, while the rest of the busbar system is a plastic body. The individual slots are electrically isolated from the other slots.

According to a further aspect of the invention, the busbar system consists of a plastic part with metal inserts in which the slots are provided. The current conductor is welded into these slots. There is a metal connection between the slots, which is also integrated into the plastic matrix. Switching units are integrated between the slots and a transverse busbar (also referred to as copper strips) described later. These switching units can be switched on and off based on signals from a microprocessor of the activation device. The switching units connect the individual slots to each other and to the copper strips in between. In this way, different parallel combinations are possible. The anode busbar, which is connected to the copper current collector (with tab), has metallic inserts made from a nickel-tin alloy. The cathode busbar, onto which the aluminum current collector is welded, has metal inserts made from an aluminum alloy.

In the cathode busbar, the respective metal insert can consist of an aluminum alloy. Because both the aluminum positive current collector and the metallic insert are made of the same material, there will be no stress corrosion. The switching units in the anode and cathode busbar are activated by an activation device. In this case, the activated switching unit can electrically connect the metallic insert to a transverse busbar (also referred to below as a copper strip), so that the current can flow from the current arrester to the copper strip. The switching elements of the switching unit ten can be made of a nickel-tin alloy or brass. Now all parallel combinations are possible. The wiring of the battery cell stack can be easily changed by means of a corresponding microprocessor signal from the activation device.

A core of the invention is that the busbar system not only has a cathode busbar and an anode busbar, but also a central busbar that connects the cathode busbar and the anode busbar to one another. The central busbar also consists of a plastic body. It has horizontal and vertical copper strips (that is, cross current bars) embedded in the plastic. Switching units are located between the horizontal and vertical copper strips. These switching units can be turned on or off based on a microprocessor signal of the activation signal. The switching units that connect copper strips (i.e. cross busbars) result in different series combinations in the battery cell assembly (i.e. in the battery module). The center busbar, the cathode busbar and the anode busbar are preferably not three separate components. Rather, the three busbars are preferably combined into a common, U-shaped component made of plastic material, in which copper strips, switching units and metal inserts (with slots) are embedded.

According to the invention, the positive and negative terminals can be located in the cathode busbar and in the anode busbar, respectively. Alternatively, it is also possible to arrange the two terminals in the cathode busbar. An additional copper strip is needed here so that the negative terminal can be routed to the cathode busbar.

The switching units integrated in the busbar system can be activated by an external activation device that generates a local magnetic field. This magnetic field activates some switching units that are to implement the desired parallel and/or series connection. The activation device can be controlled by a microprocessor. In addition, the device is laid over the busbar system from above. A magnetic field is generated around a specific switch based on the desired parallel and/or series connection. This magnetic field releases a latch retaining spring. The switching units are placed on the spring, which moves upwards. The switching units complete the circuit and connect the cells in the desired parallel or series configuration. This activation of the switching units only takes place after the busbar has been welded to the current arrester. Typically, the current collector (with the tab) is laser welded to the metal slots in the plastic part. As soon as the busbar is welded and the switching unit is activated, the module has the appropriate parallel and series combination.

The switching unit activation device is powered externally. The switching unit activation device generates a local magnetic field. This releases the latch holding the switch unit. The switching unit is pressed by a spring. As soon as the switching unit is pressed down, it touches the copper strip and creates a series and parallel combination. The microprocessor only energizes the switching units that need to be activated. Other switching units do not receive a magnetic field and therefore remain latched and deactivated.

The main differences between the invention and the prior art are as follows: Thus, the cells are arranged in the battery cell stack so that all copper current collectors (negative terminals) are on one side and all aluminum current collectors (positive terminals) are on the other side . The anode busbar has slots in metallic inserts made from a nickel-tin alloy. Copper tabbed conductors are laser welded into these slots. Each slot is isolated from other slots. There is no metal plate like current busbars. The cathode busbar has slots similar to the anode busbar. Here the slots are housed in an aluminum composite insert. Here, an aluminum current arrester is laser-welded to a tab with the slots. Each slot is isolated from the other slots. There are cross busbars (i.e. copper strips) placed between the slots and embedded in the plastic body. The copper strips are in the anode and cathode busbars. The copper strips have gaps. Switching units are positioned in these gaps. When the switching units are activated, current is passed through the copper strips. Otherwise the copper strip will cause an open circuit. Copper strips with switching units in the cathode and anode busbars result in a parallel combination.

The switching units are made of a nickel-tin alloy or brass. There is a center busbar between the cathode and anode busbars. Here, too, copper strips are embedded in the plastic body. In addition, switching units are embedded in the plastic body. When the switching units are activated, the copper strips complete a circuit. Copper strips and switching units in the central busbar form a series connection. The cathode and anode busbars and the center busbar together form a common component. This is made in such a way that a metal insert (with slots), copper strips and switching units are placed in a holder and then plastic is injected over these metal bodies. Metallic insert, switching unit (when engaged) and copper strips are electrically connected and together form a circuit. The plastic used consists of acrylic, silicone or high-temperature-resistant polymers that can absorb the heat of welding. The switching units are switched on and off by a magnetic field. The local magnetic field is generated by a controlled current in the switching unit activation module. This current is controlled by a microprocessor. The switching units are activated after the busbar has been welded to the current arrester.

Once the switching units are activated, they remain permanently in this position for the entire lifetime of the module. The switching unit activation device is part of a module assembly machine and is removed from the busbar system as soon as the switching units are activated. The microprocessor has different programs, so each next module can have a different parallel and series connection. Every second module (or battery cell group in general) can have a different parallel and series connection. The busbar system is the same regardless of the parallel and series connection. Only the activation of the switching units leads to a parallel and series connection for a specific module. This enables flexibility in the mass production of modules. Welding of the current collector (with tab) to the metallic insert in the anode and cathode busbar is usually done by laser welding. Other processes such as soldering, hard soldering, ultrasonic welding and die casting are also possible here. The positive terminal connects to the cathode busbar and the negative terminal connects to the anode busbar. If both the positive terminal and the negative terminal are to be connected to a common busbar, this is also possible. There is an additional copper strip for this, which is routed from the anode busbar to the cathode busbar. This copper strip carries the current from the negative terminal to the anode busbar.

The busbar system according to the invention is a universal busbar system with which any number of parallel and series combinations can be generated. It is no longer flexible once the switching units are activated by the activation device. In this case, the busbar system is set to a wiring scheme. The invention is applicable in particular to pouch cells or to prismatic cells.

Significant aspects of the invention are again highlighted in detail below: The cathode collectors and the anode collectors of the battery cells can be electrically connected to one another by means of a busbar system according to the invention. The busbar system has switching units that can be used to enable or disable different current paths between the battery cells. In this way, the battery cells can be connected to one another in different connection schemes in parallel and/or in series.

In a technical implementation, the busbar system can have transverse busbars. These extend between the cathode side and the anode side of the battery cell assembly. In this case, a transverse busbar is arranged between adjacent battery cells. Each of the transverse busbars can be coupled or decoupled at a cathode switching point by means of switching units with one or with both cathode conductors of the adjacent battery cells. Alternatively and/or additionally, the respective transverse busbar can be coupled or decoupled at an anode switching point by means of switching units with one or both anode conductors of the adjacent battery cells. In addition, the transverse busbar can be divided into busbar segments transversely to the stacking direction. These can be electrically coupled or decoupled with the aid of at least one switching unit. A battery cell arranged on the end face of the battery cell assembly can be connected to the positive cell assembly terminal with its cathode conductor. In contrast, the battery cell arranged on the other end of the battery cell assembly can be connected to the negative cell assembly terminal with its anode conductor.

For easy handling, for example installation of the busbar system, it is preferred if the transverse busbars and the switching units are embedded in a one-piece U-shaped plastic component. The U-shaped plastic component can enclose the battery cell assembly from above. In addition, the U-shaped plastic component can be formed from a cathode busbar arranged on the cathode side of the battery cell assembly, from an anode busbar arranged on the anode side of the battery cell assembly, and from a middle busbar, which comprises the cathode busbar and the anode busbar connect with each other. The middle busbar preferably extends on the upper side of the battery cell assembly.

Metal insert parts (that is to say metal inserts) which are electrically isolated from one another can be embedded in the cathode busbar. Each of the metal insert parts can have a receiving slot into which a cathode conductor of the battery cell len can be plugged in and is thus electrically connected. In the same way, metal insert parts (that is to say metal inserts) which are electrically isolated from one another can be embedded in the anode busbar. These can each have a receiving slot into which an anode conductor of the battery cells can be inserted and can be electrically connected to it.

In the busbar system according to the invention, the metal inserts that are in contact with the anode conductors are made of a copper-nickel-tin alloy. The metal inserts in contact with the cathode arresters are made of aluminum alloy. In contrast, the busbar metal insert known from the prior art is made of a copper-nickel-tin alloy. The switching elements are also made of copper-nickel-tin or brass.

A transverse busbar can be positioned in each case between adjacent insert parts of the cathode busbar and the anode busbar in the stacking direction. In this case, the insert parts can form electrical contacts, which can be electrically coupled to the arranged transverse busbar via the switching units.

The switching units can each have a switching element that can be stroke-adjusted in a switching housing. After completion of the battery cell assembly, the switching units can be in a decoupling position, in which electrical decoupling is produced in the busbar system. In the decoupling position, the switching element of the respective switching unit can be supported by means of spring pretension against a latch that is in the locking position. When the bolt is adjusted from its locking position to its release position, the switch element that can be adjusted in stroke can be brought into its coupling position by means of the spring preload. In the coupled position, the switching element can produce an electrical coupling in the busbar system.

The busbar system can have a large number of switching units which, depending on a desired wiring scheme, either remain in the decoupled position or have to be moved into the coupled position. Against this background, a process-technically simple control of the switching units of the busbar system is of great importance. In a preferred embodiment, the bolt of the respective switching unit can be moved from its locking position to its release position by means of magnetic force. With the help of the preferably external activation device, local magnetic fields can be generated on the busbar system as a function of a target interconnection scheme to be set. The bolts of the selected switching units can thus be moved into the release position via magnetic force in order to bring their switching elements into the coupled position.

An exemplary embodiment of the invention is described below with reference to the accompanying figures.

• 1 bis 3 jeweils Ansichten eines Batteriezellverbands mit zugeordnetem Busbarsystem;
• 4 das Busbarsystem mit weggelassenem Batteriezellverband;
• 5 bis 8 jeweils Ansichten, anhand derer der Aufbau und die Funktionsweise von Schalteinheiten veranschaulicht ist;
• 9 eine Schaltmatrix zur Einstellung unterschiedlicher Verschaltungsschemata im Batteriezellverband;
• 10a in einer Ansicht entsprechend der 3 den Stromweg bei einem ersten Verschaltungsschema;
• 10b ein vereinfachtes Schaltbild, das sich für das erste Verschaltungsschema ergibt;
• 11a und 11b jeweils Ansichten entsprechend der 10a und 10b, die ein zweites Verschaltungsschema betreffen; und
• 12 bis 22 Ansichten weiterer Ausführungsbeispiele.

Show it:

• 1 until 3 each view of a battery cell assembly with associated busbar system;
• 4 the busbar system with the battery cell assembly omitted;
• 5 until 8th each views, based on which the structure and operation of switching units is illustrated;
• 9 a switching matrix for setting different wiring schemes in the battery cell assembly;
• 10a in a view according to the 3 the current path in a first interconnection scheme;
• 10b a simplified circuit diagram that results for the first wiring scheme;
• 11a and 11b each views according to the 10a and 10b , which relate to a second wiring scheme; and
• 12 until 22 Views of further exemplary embodiments.

In the 1 until 3 a battery cell assembly is shown, which consists of battery cells 1 stacked one behind the other in the stacking direction x. The battery cells 1 can be pouch cells, for example, which have cathode conductors 3 and anode conductors 5 on both sides in the transverse direction y of the stack. According to the invention 1 until 3 all cathode conductors 3 on the (in the 1 until 3 right) cathode side of the battery cell assembly grouped, while all anode arresters 5 on the (in the 1 until 3 left) anode side of the battery cell assembly are grouped, which is opposite the cathode side in the stack transverse direction y.

In the 3 the battery cell assembly is shown in an exploded view, in which a cathode busbar 7 arranged on the right cathode side and an anode busbar 9 arranged on the left anode side are shown detached from the battery cell stack and pivoted by 90° so that their Inner sides can be seen, which face the battery cell stack in the assembled state. The cathode busbar 7 and the anode busbar 9 are in the 2 via a central bus bar 11 with each other bound, which extends over the top of the battery cell assembly. The cathode busbar 7, the anode busbar 9 and the central busbar 11 are components of a busbar system 6 according to the invention ( 2 ), which has switching units Pin described later, with the help of which different current paths I ( 10a or 11a) between the battery cells 1 can be released or blocked, so that the battery cells 1 can be connected to one another in any connection scheme in parallel and/or in series. In the 2 the busbar system 6 according to the invention is implemented as a U-shaped plastic component which encompasses the battery cell assembly from above.

How from the 4a shows, the cathode busbar 7 has metal insert parts 13 that are electrically insulated from one another and have receiving slots 15 (in Fig 3 shown) on. A corresponding cathode conductor 3 of the battery cells 1 can be inserted into the receiving slots 15 of the insert parts 13 and can be welded thereto, ie electrically connected thereto. In the same way, insert parts 17 ( 4 ) with receiving slots 15 ( 3 ) Embedded, in which the anode conductor 5 of the battery cells 1 can be inserted and welded in order to establish an electrical connection.

In the 4a the busbar system 6 is shown with the battery cell stack omitted. The cathode busbar 7, the central busbar 11 and the anode busbar 9 are in the 4a are not shown aligned in a U-shape with one another, but rather are all shown in a common drawing plane. Accordingly, the busbar system 6 has transverse busbars 19 which extend in the transverse direction y of the stack between the cathode side and the anode side of the battery cell assembly. In each case one of the transverse busbars 19 is arranged between adjacent battery cells 1 . Viewed in the stacking direction x, the transverse busbars 19 are each positioned between adjacent insert parts 13 , 17 in the anode busbar 9 and in the cathode busbar 7 . The transverse busbars 19 extend in the transverse direction y of the stack beyond the middle busbar 11 into the cathode busbar 7 and into the anode busbar 9.

The insert parts 13, 17 form electrical contacts which can be electrically coupled to the respective transverse busbar 19 via the switching units Pin. The switching units are in the pin 4a indicated only roughly schematically by circular areas. How from the 4a As can further be seen, the cathode busbar 7 has a positive cell assembly terminal 21 , while the anode busbar 9 has a negative cell assembly terminal 23 . The two terminals 21, 23 are each electrically connected to a cathode conductor 3 or anode conductor 5 of a respective battery cell 1 on the end face.

How from the 4a As can further be seen, each of the transverse busbars 19 is divided into four individual busbar segments in the stack transverse direction y, which can be electrically coupled or decoupled at a total of three central switching points using switching units Pin.

Alternatively to 4a is in the 4b a busbar system 6 is shown, which is largely identical to that in FIG 4a shown busbar system 6 is. In contrast to 4a are in the 4b the positive and negative terminals 21, 23 are arranged in the cathode busbar 7. For this purpose, an additional transverse busbar 19 is installed in the busbar system 6 , which connects the anode arrester 5 of the upper end-side battery cell 1 to the negative terminal 23 .

The following are based on the 5 until 8th the structure and function of the pin switching units are described. That's the one in the 5 Switching unit Pin shown also embedded in the busbar system 6, in particular in the plastic material of the U-shaped plastic component. The switching unit Pin has a switching housing 25 in which a stroke-adjustable switching element 27 is guided. According to the 4 until 6 the switching element 27 is prestressed in the switching housing 25 by means of a spring 29 . In addition, a bolt 31 is mounted in the switch housing 25 so that it can be adjusted transversely to the switching element 27 . The bolt 31 is in the 5 pressed by a compression spring 33 in its locking position. In the locked position ( 5 ) the switching element 27 is supported against the bolt 31, as a result of which an electrical decoupling is produced between the contact points K1, K2 in the busbar system 6. The bolt 31 has according to the 4 until 7 a ferromagnetic component 35 on. By applying a local magnetic field to the switching unit Pin, the latch 31 can therefore move into a release position ( 6 ) can be adjusted. In this release position ( 6 ) the switching element 27 can be brought into its coupling position by means of the spring preload, in which the switching element 27 produces an electrical coupling between the two contact points K1, K2 in the busbar system 6.

Immediately after completion of the battery cell assembly, all switching units Pin of the busbar system 6 are in their decoupling position ( 5 ). In order to provide the battery cell assembly with a target wiring diagram V _is ( 8th ) an activation device 37 ( 8th ) to be provided. With the help of the activation device 37, in Local magnetic fields _{are to} be generated on the busbar system 6 as a function of the target wiring diagram V to be set. With their help, the latches 31 of selected switching elements Pin can be moved to the release position so that their switching elements Pin are in the coupled position ( 6 and 7 ) toggle. After the local magnetic fields have been eliminated, the bolt 31 is returned to its locking position by means of the compression spring 33 ( 7 ). In this case, the bolt 31 engages in a form-fitting manner in a corresponding recess 39 which is formed on the switching element 27 . In this way, an unintentional shift back of the switching element 27 into its decoupling position ( 5 ) prevented.

Different wiring schemes can be implemented in the battery cell group 9 are listed and on the top line all switching elements Pin are applied. “1” symbolizes a coupled position of the respective switching element Pin, while “0” symbolizes a decoupled position of the respective switching element. On the right-hand side of the switching matrix, two columns are labeled "P" and "S", which relate to the wiring scheme that is set in each case, with "P" reflecting the number of parallel connections in the battery cell array, while "S" reflects the number of series connections in the battery cell array.

An example is in the 10a and 10b the current path I shown, which results from the first wiring diagram 1 P6S. Alternatively, in the 11a and 11b the current path I shown, which results in a second wiring scheme 2P3S. The other interconnection schemes 3P2S, 2P2S, 4P1S and 6P1S can also be formed in the same way.

The following is based on the 12 until 22 further embodiments of the invention described. Accordingly, the switching units Pin are implemented as connecting elements, for example as connecting pins. The pins Pin are arranged on the activation device 37 before the activation step is carried out. The release of the pins Pin is activated by an external power supply that creates a local magnetic field. This magnetic field is created by energizing the area near the switch that is intended to be actuated. The activation device 37 is in turn controlled by a microprocessor. Each pin is surrounded by switches that control the flow of current near the pin. This device is fitted around the busbar system 6 . Depending on which switch is actuated, a magnetic field is created around certain pins. This magnetic field releases the pins and brings them into a current-conducting coupled position. The activated pins Pin therefore complete the circuit and connect the cells 1 in the desired parallel or series combination. This activation step only takes place after the busbar system 6 has been welded to the cathode and anode conductors 3, 5. Normally, the arrester 3, 5 is welded to the metal slots 15 in the busbar system 6 by means of laser welding. As soon as the busbar system 6 has been welded to the cathode and anode conductors 3, 5 of the battery cells 1 and the activation step has then taken place, the battery cell assembly has the corresponding parallel and series combination. Each additional busbar system 6 can have a different parallel and series combination. The activation device 37 is removed from the battery cell assembly after the activation step has been completed. The activation step is followed by a fastening step in which the connecting pins Pin are permanently fixed in the busbar system 6 .

In the activation step above, the microprocessor of the activation device 37 only sends power to the areas near the pins Pin that need to be activated. Other pins Pin that do not receive a magnetic field are not pressed and remain inoperative. It should be emphasized that the activation of the connecting pins Pin by means of magnetic force is only one way of bringing the pins Pin into the coupled position. The activation device 37 releases the pin Pin by locally triggering a magnetic field, so that the pin Pin can be inserted into a pin receptacle 40 ( 13 ) between metal inserts 41 and into the space between the two contacts K1 and K2. However, the invention is not limited to this variant. Rather, the connecting pins Pin can also be brought into the coupling position in any other way.

In the illustrated embodiment, the connecting pin Pin is made of solid material, such as copper or bronze.

How from the 13 and 14 shows, the connecting pin Pin in the pin receptacle 40 of the busbar system 6 is pushed into its coupling position ( 14 ) retracted. In the mating position, the connector pin head bears laterally against metal inserts 41, the upper half 43 of which is formed of aluminum and the lower half 45 of bronze or copper. In the coupled position shown ( 14 ) the connecting pin connects the two contacts K1 and K2 in the busbar system 6.

This is followed by a laser welding step ( 15 and 16 ). Laser welding is used to permanently connect the pin to the metal inserts 41 . As already mentioned, there is the upper half 43 of the metal inserts 41 in aluminum and the lower half 45 in a copper alloy (e.g. bronze). In the laser welding step only the upper metal insert half 43 made of aluminum (melting temperature in the range of 660°C) is melted (see melt pool 46 in Fig 16 ), while the lower metal insert half 45 of copper (melting temperature in the range of 1084°C) remains in the solid state. Aluminum is therefore a welding process, while copper is a soldering process. By controlling the heat input during the process, the seam width of the intermetallic compounds can be reduced, resulting in a more homogeneous interface with good mechanical, corrosive and electrical properties. The laser soldering process is based on the principle of laser keyhole welding. The beam is emitted from the laser welding device 50 ( 16 or 18 ) is focused onto the material surface with an energy density of at least 1 MW/cm ² , thereby melting and evaporating the aluminum material of the metal inserts 41 . The vaporized metal forms a hole in which the laser reflects multiple times, increasing the energy absorption of the metal. This high energy input allows for a fast process and selective melting of the upper aluminum while leaving the lower copper in the solid state, which is why the process is called the brazing process. The realized melt layer thickness between Al and Cu can be reduced to less than 5 µm. The formation of an intermetallic compound between aluminum and copper is minimized, resulting in a ductile metal compound with reduced electrical resistance. Argon helps protect the weld from contamination from the atmosphere.

In the 17 and 18 an alternative laser welding step is shown. Thus, the metal inserts 41 are formed entirely of one type of material, namely copper or a copper alloy such as bronze. Laser welding is carried out without additional material. This means that the copper alloy pin Pin and the metal insert 41 (copper alloy) melt at the interface and permanently bond the pin Pin to the metal insert. The shape of the pin is the same as in laser soldering, as already explained, but no additional material is required here.

In the 17 and 18 laser welding occurs at the interface between the pin and the metal insert 41 (which is also made of a copper alloy). Here the interface is melted under an argon atmosphere and then solidifies into a thin weld seam. In this way the pin Pin is permanently connected to the metal insert 41 . The heat is applied locally at the interface between the metal insert 41 and the pin, so that the surrounding plastic body 47 of the busbar system 6 is not affected by this heat. Since copper is a strong heat reflector, it is advisable to use a green laser.

It should be emphasized that the invention is not limited to a welded connection of the connecting pins Pin in the busbar system 6 . Rather, the connecting pins Pin can also be permanently fastened in the busbar system 6 in any other manner. Example takes place in the 19 until 22 the permanent attachment of the connecting pins Pin in the busbar system 6 by means of a screw connection. According to the 19 the connecting pin Pin is brought into the vicinity of the space between the contacts K1 and K2 in the busbar system 6 by means of the activation device 37 . The connecting pin Pin is connected to that of the activation device 37 by magnetic force. The activation device 37 releases the connection pin Pin by a local triggering of a magnetic field. As a result, the connecting pin Pin is pressed into the pin-receiving space of the busbar system 6 and between the contacts K1, K2. In contrast to the previous embodiment, metal inserts 41 are not required.

The connecting pin Pin has a screw hole 49 in the 21 is interspersed with a screw 48. Alternatively, the connecting pin according to the Pin 22 are also screwed to the plastic body 47 of the busbar system 6 by means of several screws 48 .

During the assembly process, the connecting pin Pin is moved downwards until it comes into contact with the lower plastic body 47 of the busbar system 6 . A screw 48 is then passed through the center of the connecting pin Pin and then screwed into the plastic body 47 . The connecting pin Pin is permanently connected to the busbar system 6 in this way. The connecting pin connects the two contacts K1, K2 of the busbar system 6.

In addition, an insulating plate 53 ( 22 ) made of flexible plastic (e.g. polyurethane) can be placed on top of the connecting pin Pin. The connecting pin Pin is then screwed to the insulating plate 53 and the upper plastic body 47 .

The insulating plate 53 prevents current from flowing to the outer body via the connection pin Pin. Here the connection pin Pin does not have to be connected to the lower plastic body 47 . In this case, the connecting pin Pin is normally connected to the insulating plate 53 before it is inserted into the busbar system 6 . The insulating plate 53 can be fixed with a central screw 48, the complete assembly of the connecting pin Pin with the insulating plate 53 being carried out by the activation device 37 by vacuum. It is also possible to use an insulating plate 53 for all connecting pins Pin.

Reference List

1

battery cells

3

Cathode Arrester

5

anode arrester

6

busbar system

7

cathode busbar

9

anode busbar

11

Central bus bar

13

cathode-side insert parts

15

receiving slots

17

anode-side insert parts

19

cross busbars

21

positive cell cluster terminal

23

negative cell cluster terminal

25

switch housing

27

switching element

29

switching element spring

31

bars

33

latch compression spring

35

ferromagnetic component

37

activation device

39

recess

40

pin receptacle

41

metal inserts

43

upper metal insert half

45

lower metal insert half

46

melt pool

47

plastic body

48

screws

49

screw hole

50

laser welding device

53

insulating panel

K1, K2

contact points

Pin code

switching units

x

stacking direction

y

cross-stack direction

e.g

vertical direction

I

current path

vs

target interconnection scheme

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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

• WO 2019/060047 A1 [0008]
• WO 2016/053415 A1 [0008]

Claims (10)

Battery cell assembly, with battery cells (1) stacked one behind the other in a stacking direction (x) and having cathode conductors (3) and anode conductors (5) aligned in the transverse direction (y) of the stack, the cathode conductors (3) and the anode conductors Arresters (5) of the battery cells (1) are electrically connected to one another by means of a busbar system (6) according to a predetermined wiring diagram (V _set ), characterized in that the battery cell assembly is assigned an activation device (37) with which, depending on a wiring diagram to be set (V _target ) switching units (pin) can be activated in the busbar system (6) in order to define the wiring scheme (V _target ) in the battery cell assembly. battery cell group claim 1 , characterized in that during the manufacturing process of the battery cell assembly, the switching units (pin) are in their decoupling position, i.e. deactivated, so that no wiring diagram has yet been defined, and that at the end of the manufacturing process there is an activation step in which the activation device (37) predetermined switching units (pin) can be brought into their coupling position, i.e. can be activated, so that the wiring diagram (V _set ) is fixed in the battery cell assembly, and that, in particular, after the activation step has taken place, the activation device (37) can be removed from the busbar system (6) of the battery cell assembly. battery cell group claim 1 or 2 , characterized in that different current paths (I) between the battery cells (1) can be enabled or blocked by means of the switching units (pin) located in the busbar system (6), so that the battery cells (1) can be connected in parallel and/or in series in different connection schemes can be connected to one another and/or that in the battery cell assembly all the cathode arresters (3) are arranged on a cathode side of the battery cell assembly and all anode arresters (5) are arranged on an anode side of the battery cell assembly, which is perpendicular to the cathode side Stacking direction (x) opposite. battery cell group claim 3 , characterized in that the busbar system (6) has transverse busbars (19) which extend between the cathode side and the anode side of the battery cell assembly, and that viewed in the stacking direction (x) between adjacent battery cells (1) in each case a transverse busbar ( 19) is arranged, and that the transverse busbar (19) can be coupled or decoupled to one or both cathode conductors (3) of the two adjacent battery cells (1) by means of switching units (pin), and/or that the transverse busbar ( 19) can be coupled or decoupled to one or both anode conductors (5) of the two adjacent battery cells (1) by means of switching units (pin). battery cell group claim 4 , characterized in that the transverse conductor rail (19) is divided transversely to the stacking direction (x) into rail segments, which can be electrically coupled or decoupled with the aid of at least one switching unit (pin), and/or that a battery cell arranged on the end face of the battery cell assembly (1) is connected with its cathode arrester (3) to a positive cell assembly terminal (21), and that the battery cell (1) arranged on the other end of the battery cell assembly has its anode arrester (5) connected to a negative cell assembly terminal Terminal (23) is connected. Battery cell assembly according to one of Claims 4 or 5 , characterized in that the transverse busbars (19) and the switching units (pin) are embedded in a U-shaped plastic component which encompasses the battery cell assembly from above, and in that in particular the U-shaped plastic component consists of a cathode busbar (7) , an anode busbar (9) and a central busbar (11) connecting the cathode busbar (7) and the anode busbar (9) to one another, and that in particular the cathode busbar (7) has insert parts that are electrically insulated from one another (13), each of which can be electrically connected to a corresponding cathode conductor (3), and/or that the anode busbar (9) has insert parts (17) that are insulated from one another and each have a corresponding anode conductor (5) are electrically connectable, and that a transverse busbar (19) is arranged between adjacent insert parts (13) of the anode busbar (9) and between adjacent insert parts (17) of the cathode busbar (7), in particular in the stacking direction (x), and that in particular the insert parts (13, 17) form electrical contacts which can be electrically coupled to the transverse busbar (19) via the switching units (pin). Battery cell assembly according to one of the preceding claims, characterized in that each of the switching units (pin) has a switching housing (25) with a stroke-adjustable switching element (27), and that in a deactivated state the switching units (pin) are in the decoupling position, and that in particular the switching element (27) of the respective switching unit (pin) is supported in the decoupling position by means of spring pretension against a bolt (31) in the locking position, and that when the bolt (31) is adjusted into its release position the switching element (27) by means of the spring pretension in his coupling position can be brought in the the switching element (27) creates an electrical coupling in the busbar system (6), and that in particular the bolt (31) can be moved from its locking position to its release position by means of magnetic force, and that in particular by means of the activation device (37) depending on the wiring scheme to be set (V _{is intended} ) local magnetic fields can be generated, with the help of which the bolt (31) of predetermined switching units (pin) can be moved into the release position in order to bring their switching elements (27) into the electrically conductive coupling position. Battery cell assembly according to one of the preceding claims, characterized in that the respective switching unit (pin) is designed as a connecting pin, and that the connecting pin (pin) is held on the activation device (37) before an activation step is carried out, and in that in the activation step the connecting pin (pin ) can be released by the activation device (37) and brought into a current-conducting coupling position, in which electrical contacts (K1, K2) in the busbar system (6) are electrically closed. battery cell group claim 8 , characterized in that the activation step is followed by a fastening step in which the activated connecting pins (pin) can be permanently fixed in their coupled position, for example by a welded connection or by a screw connection. Method for producing a battery cell assembly according to one of the preceding claims, wherein during the manufacturing process the switching units (pin) located in the battery cell assembly are in their decoupled position, i.e. deactivated, so that no wiring diagram is yet defined in the battery cell assembly, and wherein an activation step is carried out at the end of the manufacturing process takes place, in which an external activation device (37) is used to set a wiring diagram (V _set ) that is to be set in the battery cell assembly.

Images