Battery module and aircraft with a battery module

A battery module is disclosed, which includes: a multiplicity of battery cells; a printed circuit board with a first series-connector with a first pad area and a second pad area, and a second series-connector with a third pad area and a fourth pad area; a cross-connector, which connects the first series-connector between the first pad area and the second pad area with the second series-connector between the third pad area and the fourth pad area; and a sensor configured to detect a cross-current at the cross-connector. The first contact electrode of a first battery cell is connected with the first pad area. The second contact electrode of a second battery cell is connected with the second pad area. The first contact electrode of a third battery cell is connected with the third pad area. The second contact electrode of a fourth battery cell is connected with the fourth pad area.

The present patent document claims the benefit of European Patent Application No. 19 201 080.9, filed Oct. 2, 2019, which is hereby incorporated by reference.

TECHNICAL FIELD

The disclosure relates to a battery module and an aircraft with a battery module.

BACKGROUND

In aviation, in particular in electrical aviation, battery performance and monitoring thereof is a critical problem which may affect flight safety, system, or battery module performance or lifespan.

Several measures may be needed to provide adequate battery management, which would lead to a certain amount of weight and space, which mostly is not desired in aviation or other mobility applications. Moreover, installing such a high-performance battery management system in an aircraft may not be feasible. From a safety point of view, overtemperature in batteries may cause fire on board or a battery shutdown, even when detected only at one single point. Besides, uneven temperature distribution may result in shorter battery lifespan.

For instance, to realize an electrical connection between a balancing busbar and individual battery cells in a battery module, wire bonding may be used. However, if one or more bond connection fails, a safety issue arises.

In aviation, multiple bonding may be used for increasing reliability. However, monitoring the health of the bonds in case of redundant bonding is an unsolved problem. In case of electric aviation, this is an extremely important issue, because there may be an extremely high power demand for example during takeoff and a partially failed cell connection may lead to a fire on board.

SUMMARY AND DESCRIPTION

The problem to be solved is to provide an effective battery management system for a battery, in particular in an aircraft environment. In particular, the problem to be solved is to detect partially or entirely failed cell connections, in particular in an efficient and in terms of speed quickly detecting way.

The problem of the disclosure is solved by a battery module, which includes a multiplicity of battery cells. Each cell of the multiplicity of battery cells has a first contact electrode and a second contact electrode. The battery module further includes a printed circuit board with a first series-connector with a first pad area and a second pad area, and at least one second series-connector with a respective third pad area and a respective fourth pad area. The battery module further includes at least one cross-connector, which connects the first series-connector between the first pad area and the second pad area with the at least one second series-connector between the third pad area and the fourth pad area. The first contact electrode of a first battery cell of the multiplicity of battery cells is connected with the first pad area by a first wiring component. The second contact electrode of a second battery cell of the multiplicity of battery cells is connected with the second pad area by a second wiring component. The first contact electrode of a third battery cell of the multiplicity of battery cells is connected with the respective third pad area of the at least one second series-connector by a respective third wiring component. The second contact electrode of a fourth battery cell of the multiplicity of battery cells is connected with the respective fourth pad area of the at least one second series-connector by a respective fourth wiring component. The battery module further includes at least one sensor configured to detect at least one cross-current at the at least one cross-connector.

Thus, a lightweight and effective battery monitoring is enabled by the surveillance of the one or more cross-currents between series circuits of battery cells, which are interconnected in parallel by one or more cross-connectors.

In a further development, the sensor includes a hall sensor or a temperature sensor.

Thus, an efficient surveillance of the one or more cross-current is provided, because the electric load of the battery module leads to significantly increased cross-currents, which may be easily detected by the proposed sensors.

In case of a fault of one element of the battery module, a cross-current may flow through one or more cross-connectors, which indicates an asymmetric balance of the currents flowing through the individual cells, e.g., the series-connectors.

The arrangement is similar to a measurement bridge known in the art.

However, the disclosure provides a combined implementation of such a bridge together with a cell interconnection of the battery module.

In a further development, the sensor is embedded into the printed circuit board.

Thus, a simple and effective coupling is provided between the sensors or components thereof and the one or more cross-connectors where the cross-currents flow in case of a fault.

The problem of the disclosure is also solved by an aircraft, (e.g., with an electric propulsion system), including the battery module according to the disclosure, which powers the electric propulsion system.

All combinations of further developments are explicitly suggested to be combined, and further synergistic effect may be achieved.

It is noted that further parts for the operation of the battery module are not depicted, (e.g., mounting parts, power supply, electric load, or electronic control components). For the sake of better understanding, these parts are not illustrated and described.

DETAILED DESCRIPTION

FIG.1depicts a schematic side view of a standard battery cell10with a cylindrical shape. The battery cell10includes a negative electrode11, a cell body12, and a positive electrode13.

The battery cell10is one embodiment of a battery cell for the battery module, as the shape or geometry is not essential for the principle of the disclosure.

FIG.2depicts an embodiment with a battery module1, installed at an aircraft6with an electric propulsion3. The battery module1includes a multiplicity of battery cells and powers, (e.g., drives), the electric propulsion7.

FIG.3andFIG.4depict an embodiment of the battery module1.

The battery module1includes a multiplicity of battery cells10,20,30,40,50,60,70,80, wherein each cell has a first contact electrode11,31,51,71and a second contact electrode13,23,43,63,83, similar to the negative electrode11and positive electrode13inFIG.1.

The battery module1further includes a printed circuit board2.

The printed circuit board2includes a first series-connector101with a first pad area102and a second pad area103.

The printed circuit board2includes three second series-connectors111,121,131with a respective third pad area112,122,132and a respective fourth pad area113,123,133.

The printed circuit board2includes further three cross-connectors201-203, which connect the first series-connector101with each of the second series-connectors111,121,131.

The first series-connector101is connected with the respective cross-connectors201-203between the first pad area102and the second pad area103.

The respective second series-connectors111,121,131are connected with the respective cross-connectors201-203between the third pad area112,122,132and the fourth pad area113,123,133.

The first contact electrode11of a first battery cell10of the multiplicity of battery cells10,20,30,40,50,60,70,80is connected with the first pad area102by a first wiring component311,312.

The second contact electrode23of a second battery cell20of the multiplicity of battery cells10,20,30,40,50,60,70,80is connected with the second pad area103by a second wiring component321,322.

The first contact electrode31,51,71of a third battery cell30,50,70of the multiplicity of battery cells10,20,30,40,50,60,70,80is connected with the respective third pad area112,122,132of the at least one second series-connector111,121,131by a respective third wiring component331,332,351,352,371,372.

The second contact electrode43,63,83of a fourth battery cell40,60,80of the multiplicity of battery cells10,20,30,40,50,60,70,80is connected with the respective fourth pad area113,123,133of the at least one second series-connector111,121,131by a respective fourth wiring component341,342,361,362,381,382.

The wiring component311,312,321,322,331,332,341,342,351,352,361,362,371,372,381,382may be one or more bond wires, which are soldered, welded, or glued to the pad areas102,103,112,113,122,123,132,133and the battery electrodes11,31,51,71,23,43,63,83, respectively.

The one or more bond wires, (e.g., two bond wires), may have a circular or a rectangular cross section and may be made of copper, aluminum, or gold.

The battery module1further includes sensors3-5configured to detect cross-currents211-213,221-223at the cross-connectors201-203.

The missing bonding wire341may have several reasons, for instance, a broken wire or a lost connection at the welding point of the wire at the battery cell40. A damaged conductor at the printed circuit board2may also be a reason for the malfunction of the battery module1.

InFIG.3, a battery module1in regular operation is shown, where each interconnection between the printed circuit board2and the respective battery cell includes two wiring components311,312,321,322,331,332,341,342,351,352,361,362,371,372,381,382in form of bonding wires.

Series-currents105,115,125,135at the series-connectors101,111,121,131are symmetrically balanced at regular operation and thus, cross-currents211-213are minimal or zero.

In case of a fault of the battery module at one element of the battery module1, as indicated inFIG.4by the missing bonding wire341, cross-currents221-223may flow through the cross-connectors201-203, which indicates an asymmetric balance of the series-currents106,116,126,136flowing through the individual cells, e.g., the series-connectors101,111,121,131. In other words, cross-currents221-223are not zero.

The asymmetric balance of the series-currents106,116,126,136may be detected by the bridge arrangement, which enables a combined implementation of such a bridge to monitor the cross-currents211-213and221-223together with a cell interconnection structure100of the battery module1.

The missing bonding wire341inFIG.4leads to a higher connection resistance between bonding pad area113and the battery cell40, because the overall cross section of the resulting bonding component includes only wire342.

Each bonding component may have sufficient dimensions that it may support the respective cell current without further bonding components to the same cell.

The sensors3-5may include a hall sensor to detect a magnetic field caused by the cross-currents211-213,221-223.

The sensors3-5may alternatively or additionally include a temperature sensor to detect a temperature or a temperature gradient caused by the cross-currents211-213,221-223.

The sensors3-5may be embedded, e.g., in a multi-layer board, into the printed circuit board2to achieve a tough coupling between a sensor component, like a loop, and the respective cross-connector201-203.

The cross-connectors201-203itself may be embedded, for instance, to allow to provide a surface mounted temperature sensor element, e.g., a PT100 resistor.

In certain examples, the battery module may include a high number of battery cells and a high number of the interconnection structures100as described before.

Moreover, further measurement components are necessary to perform the current measurement with the bridge configuration as described above.

Although the disclosure has been illustrated and described in greater detail by the exemplary embodiments, the disclosure is not restricted by these exemplary embodiments. Other variations may be derived herefrom by the person skilled in the art, without departing from the scope of protection of the disclosure. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.