ARRANGEMENT WITH MULTIFUNCTIONAL CONNECTION FOR ENERGY STORAGE CELLS OR ENERGY CONSUMER

Description

Technical application area

[0001] The present invention relates to an arrangement with a multifunctional connection for energy storage cells or energy consumers, comprising at least one charge equalization device and / or a measuring device for measuring an electrical voltage of the energy storage cells or energy consumers, and an electrical bridging element with an electrical connection via which the bridging element can be activated to establish an electrical connection between two electrically insulated conductors. The invention also relates to a series connection of several energy storage cells or energy consumers, each connected to such an arrangement.

[0002] For the safe and reliable operation of a series connection of energy storage cells, especially lithium-ion battery cells, bridging or bypass devices are required that can electrically bridge individual cells in the series connection in the event of a cell failure. Furthermore, reliable operation also requires monitoring of the cell voltage of the individual cells and, if necessary, a device for balancing the charge states. State of the art

[0003] From DE 37 21 754 A1, a bridging device for securing battery cells is known, which enables the irreversible bridging of high-resistance failures in damaged memory cells. The bridging device consists of two semiconductor components arranged in series in layers, each with a different current / voltage characteristic. In the event of a high-resistance failure in a damaged memory cell, the high charging current flows through the two semiconductor components, which, due to the resulting significant temperature increase, alloy and thus irreversibly short-circuit the memory cell to a low resistance.

[0004] DE 10 2012 005 979 A1 describes an electrical bridging device for bridging defective storage cells in energy storage systems, in which a sequence of layers is formed between two electrical conductors, comprising at least one electrical insulating layer and one or more reactive layer stacks in which an exothermic reaction can be triggered. The reactive layer stacks and the insulating layer are coordinated such that the insulating layer dissolves due to the heat energy released during the exothermic reaction, thereby establishing an electrical connection between the electrical conductors.

[0005] German patent DE 10 2012 205 553 A1 describes a battery cell with a device for disconnecting and / or bridging the battery cell's terminals. For this purpose, the battery cell has a mechanical safety element which, upon triggering or activation, disconnects and / or short-circuits the battery cell's terminals. The mechanical safety element is triggered by an electrical trigger signal based on a measurement detected by a monitoring sensor. Details regarding the construction and wiring of the individual elements are not provided in this document.

[0006] Currently, the safe and reliable operation of a series-connected energy storage or battery cell requires multiple connecting cables to link the bridging device, the measuring device for the battery cell's electrical voltage, and the charge equalization device to the battery cell. However, these connecting cables incur costs during the production and assembly of the battery system, and their numerous connections also reduce the system's reliability. This problem has traditionally been addressed through cost optimization and reliability improvements in wiring harnesses and connectors. However, reducing the number of connections has always resulted in reduced functionality.Designs where the jump-start device operates without external control and triggers automatically require either a significantly increased resistance of the battery cell or an interruption of the contact. Premature triggering, for example to prevent high power losses, is not possible. Therefore, safe and reliable operation of the battery system cannot be guaranteed in every case.

[0007] The object of the present invention is to provide an arrangement with a connection for energy storage cells or energy consumers that enables both the control of a bridging device and the connection of a measuring device for measuring the electrical voltage of the energy storage cells or energy consumers and / or a device for charge balancing with a smaller number of connecting lines. Description of the invention

[0008] The problem is solved by the arrangement with a multifunctional connection according to claim 1. Claim 9 relates to a series connection of several energy storage cells or energy consumers, each of which is connected to such an arrangement. Advantageous embodiments of this arrangement and of the series connection of energy storage cells or energy consumers are the subject of the dependent claims or can be found in the following description and the exemplary embodiments.

[0009] The proposed arrangement with a multifunctional connection for energy storage cells or energy consumers comprises at least one charge equalization device and / or a measuring device for measuring the electrical voltage of the energy storage cells or energy consumers, and an electrical bridging element with an electrical connection. This electrical connection allows the bridging element to be triggered or activated to establish an electrical connection between two electrically insulated conductors. The electrical connection is electrically connected to one of the two conductors via the bridging element. One of the two conductors is electrically connected, or connectable, to a first pole of the energy storage source or energy consumer, and the other conductor is electrically connected, or connectable, to a second pole of the energy storage source or energy consumer.The charge equalization device and / or the measuring device are connected to the electrical terminal of the bridging element and thus to one of the two electrical conductors. Furthermore, the arrangement includes a trigger circuit for triggering or activating the electrical bridging element, which is connected in parallel to the charge equalization device and / or the measuring device and to the electrical terminal of the bridging element. The terms "trigger" and "activate" are used synonymously in this patent application and therefore refer to the same process.

[0010] The proposed arrangement with a multifunctional connection thus enables external control of the bridging element, connection of the charge control device to the energy storage cell, and measurement of the energy storage cell's voltage via a single connection to the bridging element's electrical terminal. This significantly reduces the number of connection lines compared to the state of the art while maintaining the same functionality. As a result, in addition to cost savings, a corresponding series connection of energy storage cells can be operated with greater safety and reliability. A similar problem arises with series connections of energy consumers such as lights or heating elements. The proposed arrangement can therefore also be used with such energy consumers.The following section explains different configurations of the arrangement in conjunction with energy storage cells. However, these configurations can also be implemented in the same way in conjunction with energy consumers.

[0011] The bridging element is triggered by the trigger circuit. This circuit is connected to the bridging element via its electrical connection. The bridging element is designed and arranged such that the electrical connection for triggering the bridging element is electrically conductive via the bridging element to one of the two electrical conductors, and thus to one of the two poles or power terminals of the energy storage or battery cell. The bridging element can be triggered, for example, by switching on a trigger current via the trigger circuit. Due to the conductive connection of the electrical terminal to one of the two poles of the energy storage cell, this electrical terminal, hereinafter also referred to as the multifunctional terminal, can be used to measure the voltages of the series-connected storage cells.Simultaneously, the electrical connection can also be used to connect a charge equalization device, also known as a balancing circuit, to the energy storage cell. This also applies to energy storage cells in a series connection of identical energy storage cells.

[0012] In an advantageous embodiment, the bridging element between the two electrical conductors comprises a sequence of layers with at least one electrical insulating layer that electrically isolates the two electrical conductors from each other, and an electrically conductive reactive layer in which an exothermic reaction can be triggered via the electrical connection. This reaction causes the insulating layer to dissolve at least partially, thereby establishing an electrical connection between the electrical conductors. The bridging element can be configured as described in DE 10 2012 005 979 A1. One of the two electrical conductors is preferably electrically connected to the reactive layer from which the electrical connection of the bridging element originates.Since the reactive layer is electrically conductive, it also establishes the electrical connection of the electrical terminal to this conductor and thus to one pole of the storage cell. The individual layers of the bridging element do not necessarily have to be bonded together; they can simply lie on top of each other. The proposed arrangement exploits the fact that initiating the exothermic reaction in a reactive layer requires a current flow of a specific characteristic, such as a strong current gradient, which does not occur when measuring the cell voltage with a suitable measuring device or when using a charge equalization device. Therefore, these devices cannot trigger the reactive layer, allowing the electrical connection of the bridging element to be used by them as well.The bridging device can also be designed such that the triggering of the exothermic reactions of the reactive layer occurs through a sufficiently high current flow with a specific characteristic, e.g., via local heat generation at a contact resistance or a heating resistor. In this case as well, the required current flows are not achieved by either the cell voltage measuring device or the charge equalization device.

[0013] The trigger circuit is therefore preferably designed to generate a corresponding current flow or current gradient across the electrical connection at the reactive layer. Preferably, the trigger circuit is connected to a suitable reference potential, so that the current flows between the reference potential and the electrical connection at the junction element. In a series connection of energy storage cells, the highest or lowest potential of this series connection can be used as the reference potential. A specifically chosen potential within the series connection can also be used for this purpose.

[0014] An example of a reactive layer is a reactive nanofilm, such as a reactive Ni / Al film, as described in WO 01 / 83182 A1. Such nanofilms consist of a large number of nanolayers, for example, with layer thicknesses ranging from 1 nm to 500 nm. Typically, layers of two different materials alternate, reacting exothermically with each other upon appropriate energy input. Other reactive layers can also be used in the proposed bridging element, such as layers of nanothermite or other exothermically reacting materials.

[0015] The bridging element can also use a different mechanism to electrically connect the two electrical conductors. This mechanism must be chosen so that the bridging element is triggered by a current flow of a specific characteristic, which does not occur through the operation of the charge equalization device and / or the measuring device via the electrical connection.

[0016] Preferably, the charge balancing device (balancing circuit) is designed such that charge equalization occurs by discharging the respective storage cell through a resistor (passive balancing). Alternatively, the trigger circuit can be designed to extend a passive balancing circuit by adding a low-resistance bypass for the discharge resistor, for example, using a MOSFET in parallel with the discharge resistor. Furthermore, in a series connection of energy storage cells, the balancing circuit can be designed to achieve charge equalization by redistributing the charge to other storage cells via a suitable interconnect network (active balancing). In this case, the trigger circuit must also be designed to extend the active balancing circuit by providing a current limiting cutoff.

[0017] The energy storage cells can also include a current interrupt device (CID). The bridging elements of these arrangements can then bridge one or more interruptions in a series connection of energy storage cells, such as those caused by one or more CIDs.

[0018] The trigger circuit of the proposed arrangement can also be configured in a series connection of energy storage cells such that it draws the energy required to trigger the bridging element, e.g., to ignite the reactive layer of a correspondingly constructed bridging element, from at least one other energy storage cell in the series connection. This can be achieved, for example, by means of a so-called flying capacitor, switched capacitor, or bootstrap circuit.

[0019] The multifunctional connection of the proposed arrangement can be used to trigger a bridging element, simultaneously as a contact for cell voltage measurement, and as a connection for a balancing circuit. Only one connecting line to the energy storage cell is required for this purpose. This significantly reduces the number of connecting lines or connections required for the safe and reliable operation of a series-connected energy storage cell compared to the prior art. This increases the reliability of the overall system, as connections, plugs, and cables are a known weak point, particularly in mobile applications (due to vibrations). Furthermore, the reduced number of connections lowers the manufacturing and assembly costs of the respective battery system.The proposed arrangement can be used for all application areas of corresponding electrical bridging elements where at least one cell voltage, e.g. in batteries or fuel cells, must also be measured. Brief description of the drawings

[0020] The proposed arrangement with a multifunctional connection is explained in more detail below using exemplary embodiments in conjunction with the drawings. These show: Fig. 1 a schematic representation of a battery storage cell with the bridging element used in the present invention; Fig. 2 a more detailed representation of an exemplary embodiment of the bridging element according to the present invention; Fig. 3 an example of an embodiment of the proposed arrangement with a multifunctional connection to a battery cell; Fig. 3a an example of an embodiment of the charge equalization device; Fig. 3b an example of a trigger circuit for low-resistance bridging of the discharge resistance of the device. Fig. 3a Fig. 4 shows an example of connecting several of the proposed arrangements in a series connection of battery cells; Fig. 5 shows an example of the Figure 4with a more detailed representation of the bridging elements used as examples; Fig. 6 various schematic representations of the current paths when the bridging element is triggered in the event of a defective battery cell in a series connection of battery cells; Fig. 7 a schematic representation of the current paths when two bridging elements are triggered in a series connection of battery cells; and Fig. 8 an exemplary connection of the bridging elements of the uppermost and lowermost cell of a series connection of battery cells. Ways to implement the invention

[0021] In the proposed arrangement with a multifunctional connection, a bridging element is used to electrically bridge a defective battery cell, which can be triggered via an electrical connection connected to the bridging element in order to bridge the battery cell. Figure 1Figure 1 shows a schematic representation of an energy storage cell 100 with its two cell terminals or poles 101 and 102. The bridging element 105 has two electrical conductors 103 and 104, which are connected to the two poles 101 and 102 of the battery cell 100. The bridging element 105 is triggered via the electrical terminal 109. When the bridging element 105 is triggered, an electrical connection is established between the two electrical conductors 103 and 104 of the bridging element, thereby short-circuiting the two poles 101 and 102 of the battery cell 100.

[0022] Such a bridging element can be implemented particularly advantageously in a design as shown in the upper part of the illustration. Figure 2The bridging element is shown in cross-section. It has two electrical terminals or conductors 103 and 104, between which a sequence of layers is formed, consisting of a solderable layer 108, a reactive layer 107, an electrical insulating layer 106, and another solderable layer 108. The reactive layer 107 is formed from one or more reactive layer stacks, preferably in the form of one or more reactive nanofilms, in which an exothermic reaction can be initiated. The insulating layer 106 serves to provide high-resistance insulation for the two electrical conductors 103 and 104, and thus also for the two poles 101 and 102 of the battery cell 100.

[0023] The activation of the reactive layer 107, and thus of the bridging element, occurs via the electrical connection 109 attached to the reactive layer. This connection is linked to a triggering device not shown in the figure. This device can be, for example, a current or voltage source (e.g., a pre-charged capacitor). Activation is triggered by a current or voltage pulse, or by a current of sufficient magnitude to initiate the exothermic reaction in the reactive layer 107. This reaction results in a significant heat generation. This heat at least partially dissolves the insulating layer 106. Due to the high heat generation, the two solder layers 108 also melt. The insulating residue dissolves in the solder, creating an electrical contact between the two electrical conductors 103 and 104, and thus electrically bridging the battery cell 100.

[0024] As from the Figure 2 As can be seen, the electrical connection 109 is also in electrical contact with a terminal 101 of the battery cell via the electrically conductive reactive layer 107 and the solder layer 108. This is utilized in the present invention to connect other devices to this terminal of the battery cell via this electrical connection 109.

[0025] In the lower part of the illustration Figure 2Figure 100 is a schematic top view of battery cell 100 with its two terminals 101 and 102. This figure also shows a corresponding electrical connection 109a, which corresponds to electrical connection 109 in the upper part of the figure. Additionally, another electrical connection 109b is shown, which is optional and also corresponds to electrical connection 109 in the upper part of the figure. Connection 109b is electrically connected to connection 109a and simplifies the connection when battery cells are connected in series and terminals 101 and 102 are alternately connected to the adjacent cells (building a battery module). Connections 109a and 109b ensure that, when multiple battery cells are connected in series, the multifunctional connection 109 is always located on the same side of the module.

[0026] By electrically connecting the electrical terminal 109, used to trigger the bridging element 105, to a terminal of the battery cell 100, this terminal can also be used for other devices that need to be connected to this terminal of the battery source. This is illustrated by example and partially schematically in Figure 3 The figure shown illustrates an example of the proposed arrangement. A measuring device 112 for voltage measurement, a balancing circuit 113 for charge equalization, and the tripping circuit 114 for tripping the bridging element are connected to the multifunctional electrical connection 109 in a monitoring and control circuit 111. The tripping circuit 114 is connected via a busbar 110 (see figure). Fig. 4 / 5) is connected to a reference potential. This reference potential is preferably used for all tripping circuits 114 of a series connection of corresponding battery cells 100. The measuring device 112 and the balancing circuit 113 are in turn connected to a different potential, in this case via the electrical connection 109 of the next bridging element to the corresponding terminal 101 of the adjacent battery cell 100. This is in Figure 4The diagram schematically illustrates the three battery cells 100 connected in series with the corresponding arrangements, i.e., bridging elements 105 and monitoring or control circuits 111. The reference potential for the trigger circuits 114 can be taken, for example, from the uppermost cell of a series connection (highest voltage) or alternatively from the lowermost cell of a series connection, as indicated by the two differently dashed sections of the upper connecting line in the figure, of which only one can be implemented as a connection at any given time.

[0027] The triggering circuit 114 can be implemented, for example, by a voltage source or a current source such as a charged capacitor, which discharges into the reactive layer of the bridging element upon triggering in order to activate it. It can also be a transistor, such as a MOSFET or a thyristor, which triggers the activation current for the reactive layer.

[0028] Figure 3a Figure 113 shows an example of a balancing circuit in which charge equalization is achieved by discharging the respective storage cell via a discharge resistor 121. Charge equalization is activated by a discharge switch 122. The trigger circuit 114 can be designed to bypass the discharge resistor 121 of the balancing circuit with a low-impedance switching device 123 to activate the bypass device. A corresponding trigger circuit is shown in Figure 113. Figure 3b This is an example.

[0029] Figure 5 This design is shown again in more detail, in which the reactive layer 107 and the electrical conductors 103, 104 of the bridging element 105 can be seen.

[0030] Figure 6 The figure illustrates, in a highly schematic representation, the current paths in various fault conditions using a series connection of three battery cells 100 with the corresponding bridging elements 105. In the figure, the bridging element 105 is only indicated at the battery cell where bridging is required. The tripping circuit 114 is also only indicated in the figures by a switch. Each battery cell 100 has the two electrical leads or poles through which the battery cells are connected to each other in series.

[0031] Figure 6a) shows a case where the topmost battery cell in the series circuit is to be bypassed, with the potential of the bottommost battery cell used as the reference potential for the tripping circuit. The current path 116 for tripping the bypass element 105 of the topmost cell is indicated by the dashed line with arrows. Figure 6b) shows an exemplary current path for tripping the bypass element 105 of the bottommost cell, where the potential of the topmost cell is used as the reference potential for the tripping circuit.

[0032] The bridging element can also be used to bridge an open circuit in a battery cell, for example, an open CID 115, as illustrated in the following partial figures. Part 6c) shows one way to trigger the bridging element of the middle cell in the event of an open circuit as depicted in the figure. In this case, the voltage of the uppermost battery cell is used as the reference potential for the triggering circuit. In this and the following partial figures, the current path 116 used for triggering is again indicated by the dashed lines with arrows. In part 6d), the open circuit is located at the other terminal of the middle battery cell. Here, too, the triggering circuit is connected to the potential of the uppermost cell as the reference potential.Figures 6e) and 6f) show comparable cases, but the potential of the lowest cell is used as the reference potential.

[0033] If more than two battery cells in a series circuit fail, the individual jump-start devices must be triggered sequentially. This is illustrated by the example of... Figure 7This figure shows a series connection of four battery cells 100, where the two middle battery cells fail simultaneously and must be bypassed. Both tripping circuits are connected to the potential of the uppermost cell as a reference potential. To trip both bypass elements, the bypass element of the cell closer to the reference potential is triggered first. The corresponding current path 116 is again shown in the figure. Subsequently, the bypass element located further down in the series connection can be triggered, with the resulting current path 116 also shown in the figure. This tripping principle is applied analogously for more than two defective battery cells in a series connection.

[0034] Faults can occur that cannot be resolved by simply connecting the multifunctional terminal of all battery cells to the highest or lowest potential of the series circuit to trigger the jump-start devices. This applies to faults in the uppermost or lowest battery cell. This problem can be avoided by not connecting the electrical terminal of the jump-start device to the terminal with the highest potential in the uppermost cell and not to the terminal with the lowest potential in the lowermost cell, as described in the... Figure 8 This is shown schematically. Alternatively, the trigger circuit can of course be designed in a different form (e.g. by means of a pre-charged capacitor, as is the case in a so-called flying capacitor, switched capacitor or bootstrap circuit). Reference symbol list

[0035] 100 Battery cell 101 Cell terminal or pole 102 Cell terminal or pole 103 Electrical conductor 104 Electrical conductor 105 Bridging element 106 Insulation layer 107 Reactive layer 108 Solder layer / Solder deposit 109 Electrical connection 109a Electrical connection 109b Electrical connection 110 Connecting element 111 Monitoring / control circuit 112 Voltage measuring device 113 Balancing circuit 114 Release circuit 115 CID 116 Current path 121 Discharge resistor 122 Discharge switch 123 Switching device

Claims

1. An arrangement having a multifunctional connection for energy storage cells or energy consumers, said arrangement comprising at least - a device for charge equalisation (113) of energy storage cells and / or a measuring device (112) for measuring an electrical voltage of the energy storage cells or energy consumers, - an electrical bridging element (105) having an electrical connection (109) via which the bridging element (105) can be activated to establish an electrical connection between two electrical conductors (103, 104) which are insulated from one another and which is connected in an electrically conductive manner to one of the two electrical conductors (103, 104) via the bridging element (105), and - a trigger circuit (114) which is connected to the electrical connection (109), for triggering the bridging element (105), wherein a first of the electrical conductors (103) is connected in an electrically conductive manner to a first pole (101), and a second of the electrical conductors (104) is connected in an electrically conductive manner to a second pole (102) of an energy storage cell (100) or energy consumer, and the device for charge equalisation (113) and / or the measuring device (112) is connected to the electrical connection (109) of the bridging element (105), so that the electrical connection (109) forms the multifunctional connection.

2. The arrangement according to Claim 1, characterised in that the bridging element (105) has between the two electrical conductors (103, 104) a layer sequence having at least one electrical insulation layer (106), which insulates the two electrical conductors (103, 104) from each other, and an electrically conductive reactive layer (107), in which an exothermic reaction can be triggered via the electrical connection (109), by means of which reaction the insulation layer (106) at least partially melts, and the electrically conductive connection between the electrical conductors (103, 104) is produced.

3. The arrangement according to Claim 2, characterised in that one of the two electrical conductors (103, 104) is connected in an electrically conductive manner to the reactive layer (107), and the electrical connection (109) is formed at the reactive layer (107).

4. The arrangement according to Claim 2 or 3, characterised in that the layer sequence also has one or more electrically conductive solder layers (108), which melt as a result of the exothermic reaction in the reactive layer (107) and produce a solder connection between the two electrical conductors (103, 104).

5. The arrangement according to any one of Claims 1 to 4, characterised in that the bridging element (105) is designed such that it can be activated via the electrical connection (109) by a current flow of a certain characteristic.

6. The arrangement according to Claim 5, characterised in that the characteristic is selected such that a current flow having this characteristic is not generated via the electrical connection (109) by the operation of the device for charge equalisation (113) and / or the measuring device (112).

7. The arrangement according to any one of Claims 1 to 6, characterised in that the device for charge equalisation (113) is designed such that the charge equalisation takes place by discharging the energy storage cell (100) via a discharge resistor (121).

8. The arrangement according to Claim 7, characterised in that the trigger circuit (114) is formed by a switching device (123) for low-resistance bridging of the discharge resistor of the device for charge equalisation (113).

9. A series circuit of multiple energy storage cells or energy consumers which are each connected to an arrangement according to any one of Claims 1 to 8.

10. The series circuit according to Claim 9, in which the trigger circuit (114) of each arrangement is connected to a reference potential which is derived from one of the energy storage cells (100) or energy consumers of the series circuit.

11. The series circuit according to Claim 10, in which the reference potential is the highest or the lowest potential of the series circuit.

12. The series circuit according to any one of Claims 9 to 11, in which the device for charge equalisation (113) is in the form of an active charge equalisation circuit.

13. The series circuit according to Claim 12, in which the trigger circuit (114) is formed by a switching device for low-resistance bridging of a component or sub-circuit for current limitation which is used in the charge equalisation circuit.

14. The series circuit according to any one of Claims 9 to 13, in which the trigger circuit (114) is designed and interconnected such that it draws energy required for triggering the bridging element (105) from at least one of the other energy storage cells (100) of the series circuit.

15. The series circuit according to any one of Claims 9 to 14, in which the electrical connection (109) of the bridging element (105) is designed as a part of an electrical connection element (busbar) which connects poles of different energy storage cells or energy consumers of the series circuit to one another.