DE102022127336A1 - Battery module with a bidirectional multi-stage converter and correspondingly constructed high-voltage battery - Google Patents

Abstract

In various embodiments, a battery module (4) for a high-voltage battery (1) is provided, comprising: a module housing (43) in which a bidirectional multi-stage converter (41) and a number of battery cells (42) are arranged, wherein these are electrically connected to one another by means of a busbar (44); wherein the module housing (43) has a first and a second open groove (47) for receiving a holding rail (80) which also functions as an electrical line. Furthermore, a high-voltage battery is provided which has at least two battery modules (4) according to the invention, wherein these are fastened to one another and electrically connected to one another by means of holding rails (80, 81).

Description

The present invention relates to a battery module with a bidirectional multilevel converter and a high-voltage battery constructed on the basis of such battery modules.

The range of electric vehicles is largely determined by the traction battery installed in them. Modern electric vehicles are now powered by suitably dimensioned high-voltage batteries that are made up of battery cell modules (also known as battery modules), each of which in turn contains a number of battery cells, each of which is the smallest self-contained energy storage cell. For example, the two-layer Performance Battery Plus, which is used in some Porsche Taycan models, comprises 33 cell modules, each of which consists of twelve individual battery cells. The traction battery therefore has a total of 396 battery cells, with lithium-ion batteries being used as battery cells.

The infrastructure of electric drives for road vehicles is characterized by a strong structural separation according to their functionality. For example, the traction battery, which has several battery modules, is often installed in the vehicle floor between the axles in order to keep the vehicle's center of gravity as low as possible. The power electronics are in a "concentrated" form as a separate module, which is usually located near the traction battery.

Modern approaches dissolve this functional separation and focus on merging at least the power electronics and the battery modules. For example, the use of a multi-layer converter as a bidirectional AC-DC converter for modularizing and interconnecting battery cells is known.

This is how printed matter reveals DE 1020 11004248 A1 a circuit arrangement with a multi-stage converter for a high-voltage battery of an electric or hybrid vehicle in order to provide an output alternating voltage. The multi-stage converter comprises several converter stages connected in series, each with one or more battery cells. The publication also suggests connecting several converter stages in parallel.

Printed matter DE 102012212556 A1 discloses a battery with a plurality of battery modules for gradually adjusting a battery voltage using a multilevel converter topology. The battery cells are connected in series for this purpose.

Printed matter EN 10 2013215572 A1 discloses an electric battery with several energy storage modules connected in series, each with several battery cells. An energy storage module has a multi-voltage converter. The disclosed battery allows for easy module replacement of individual modules.

Based on this, the object of the present invention can be seen in providing a battery module by means of which new highly modular battery concepts can be realized in a simple manner.

This object is achieved by means of the subject matter of the independent patent claims. Further preferred embodiments can be found in the dependent patent claims.

According to the invention, a battery module for a high-voltage battery is provided in which energy storage cells and power electronics are arranged. The battery module according to the invention has a module housing in which a bidirectional multilevel converter and a number of battery cells are arranged, these being electrically connected to one another by means of a busbar. The battery cells are electrically connected to one another by means of the busbar in a desired type of circuit, so that the desired alternating voltage can be provided at the connection poles of the battery module by suitably adjusted operation of the multilevel converter.

The module housing of the battery module has a first and a second open groove to accommodate a holding rail, which also functions as an electrical line. To do this, the battery module can be placed on the holding rails, with one holding rail being inserted into each groove. The placement can be done from above, from below or from the side, depending on the design of a holding frame structure to which the holding rails belong.

The grooves can expediently be arranged on the module housing in such a way that a part of the busbar crosses the first groove or is arranged above it in a plan view of the module and another part of the busbar crosses the second groove or is arranged above it in the plan view. The plan view can be from the direction in which the battery module is placed or plugged onto the holding rails. In other words, the busbar can be arranged within the battery module housing, for example, in such a way that at least a part of it runs above or below the two grooves, with this part of the busbar running parallel to the groove. can be arranged or can cross them at any angle. However, it is not intended that the busbar runs through the grooves, i.e. extends between the side walls of the groove and is therefore exposed in it. The parts of the busbar which at least partially overlap the grooves when viewed from above can be regarded as the connection poles of the battery module. The busbars can generally be overmolded with an insulating plastic, except at points which are used to make contact with the holding rails, which function as electrical lines. For this purpose, corresponding areas of the busbars can be left exposed during overmolding (e.g. by covering with a panel) or the insulation can be specifically removed from corresponding areas of the busbars after overmolding.

In an exemplary embodiment, the module according to the invention can weigh less than 30 kg, so that installation by one person is possible. With regard to the structure of a corresponding battery, the module according to the invention can be viewed as a basic module which has an AC-DC bidirectional multi-level converter and a number of cell modules which provide a DC voltage.

According to further embodiments of the battery module, the two grooves can be formed parallel to one another. In general, both grooves can be formed in the same way.

According to further embodiments of the battery module, both grooves can be arranged in the same side surface of the module housing. For example, the grooves can be arranged in the bottom surface or in a side surface of the battery module according to the invention, so that the battery module is arranged on or on the holding rails during assembly of a corresponding battery.

According to further embodiments of the battery module, in at least one of the grooves, the part of the busbar crossing or overlapping it in plan view can be exposed in the groove and set back into the interior of the module housing relative to a bottom of the groove. In other words, the part of the busbar is exposed via a recess in the groove, so that there is a distance between the surface of the exposed busbar and the plane of the bottom of the groove.

According to further embodiments of the battery module, at least part of the bottom of the groove can be displaced into the interior of the module housing when force is applied to it. The at least part of the bottom of the groove can be a part of the bottom that rests against the exposed part of the busbar. In other embodiments, the entire bottom of the groove (excluding the area in which the recess is arranged) can be displaced into the interior of the module housing. The mechanical displacement can be achieved in that the displaceable part of the bottom of the groove is elastically suspended or movably mounted, for example by means of a spring or another elastic element. By applying force, the spring (or the at least one elastic element) can be compressed, whereby the corresponding part of the bottom of the groove (or the entire bottom) is displaced into the module housing. The fact that the part of the busbar is not directly exposed in the groove provides protection against contact.

According to further embodiments of the battery module, a through-opening through the housing module can be provided in at least one of the grooves in the overlap area of the busbar with the groove. The through-opening can, for example, have a thread and function as a screw opening so that a screw can be screwed into the module housing through the busbar into the holding rail. In this way, a conductive connection can be formed between the busbar inside the module housing and the holding rail, which also functions as an electrical line. In addition, the through-opening can be arranged in a recess so that the screw head is countersunk relative to the surface of the module housing, thus providing a certain degree of protection against contact. In addition, a non-conductive cap can be placed on the screw head.

According to further embodiments of the battery module, it can have a first connection and a second connection, by means of which an additional module containing battery cells can be coupled to the battery module via a parallel connection. The additional module can be an additional energy module that does not have a multi-stage converter, but is intended to enable an increase in the amount of energy in the high-voltage battery. Furthermore, it can be an additional module with an output voltage of, for example, 60 volts, so that this additional module is not a high-voltage module. Additional energy module: is connected to the base module via a DC parallel connection (increases the energy content of the battery)

According to the invention, a high-voltage battery is also provided which is constructed on the basis of the battery module described herein. The high-voltage battery therefore has at least two bat battery modules according to one of the described embodiments, wherein these are fastened to one another by means of the holding rails and are electrically connected to one another.

In principle, any number of battery modules can be present in the high-voltage battery. Depending on requirements, the modules can be connected in series and/or in parallel. A series connection of the battery modules can facilitate sufficient modeling of the output voltage (sinusoidal AC) for the operation of an electric motor. A parallel connection of the battery modules can generate a sufficiently high output current, since in general the multi-stage converter is typically a limiting factor in the DC-AC conversion of electrical power. Furthermore, a parallel connection of the battery modules within the high-voltage battery enables higher availability, since if a battery module is defective, the high-voltage battery remains operational with limited power and the electric vehicle can continue to drive.

To connect the battery modules to each other, the holder rails are used, which as a whole provide a stable holding frame and form both a stable mechanical structure and at the same time function as an electrical line.

The support rails can comprise first and second support rails. First support rails can be those that run through grooves of the battery modules. These can have a conductive core and lead the connections of the battery modules to the outside. The ends of the first support rails can be connected to second support rails at crossing points. The second support rails serve to mechanically and electrically connect the first support rails to one another. The entirety of the first and second support rails forms the support frame structure.

In order to achieve a specific connection of the battery modules within the high-voltage battery, additional external lines can be provided which provide an electrical connection between adjacently arranged holding rails. In other words, external line sections can be provided if a desired electrical connection of the battery modules cannot be realized using the first and second holding rails alone. In addition, the second holding rails in particular can only be designed to be electrically conductive in sections in order to realize a specific connection.

According to further embodiments of the high-voltage battery, it can also have a control unit that is electrically coupled to each of the battery modules. The control unit can be a central logic unit that, among other things, generates control signals to the multi-stage converters and thus regulates the energy output of the high-voltage battery, in particular the three-phase alternating current control, as well as its energy consumption. The control unit can also have other components, such as a switching matrix for different networks, a power meter, a residual current device (RCD), a device for checking the protective line (PE check) and other (decentralized) security or safety systems.

The high-voltage battery may also have any required components, such as EMI filters and galvanic isolation between the battery cell side and the connections of the high-voltage battery.

It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 zeigt eine beispielhafte Hochvoltbatterie auf Basis des erfindungsgemäßen Batteriemoduls.
• 2 zeigt eine Ausführungsform des Batteriemoduls mit Zusatzmodul.
• 3 veranschaulicht die elektrische und mechanische Verbindung zwischen den Batteriemodulen.
• 4A und 4B zeigen beispielhafte Verbindungen zwischen den Halteschienen und den erfindungsgemäßen Batteriemodulen.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

• 1 shows an exemplary high-voltage battery based on the battery module according to the invention.
• 2 shows an embodiment of the battery module with additional module.
• 3 illustrates the electrical and mechanical connection between the battery modules.
• 4A and 4B show exemplary connections between the holding rails and the battery modules according to the invention.

In 1 an exemplary high-voltage battery 1 based on the battery module 4 according to the invention is shown. A total of six battery modules 4 are shown, with two battery modules 1 each connected in parallel and a total of three such parallel circuits connected in series. The electrical connections between the battery modules 1 are indicated by lines 7. A first battery connection 10 represents a phase, a second battery connection 11 represents the connection for the neutral conductor. The 1 The circuit shown represents the voltage supply for one phase. In a three-phase electric motor, an equivalent traction battery would require the same Circuit provided for each of the two further phases.

Each of the battery modules 4 according to the invention has a multi-stage converter 41 and an arrangement of battery cells 52. When charging the battery 1, the multi-stage converter 41 converts the applied alternating voltage into a direct voltage (individually for each battery module 4). During operation of an electric vehicle, the multi-stage converter 41 converts the direct voltage of the battery 1 into a required pulsed voltage. In this respect, the multi-stage converter 41 can be considered a power electronics component for the respective battery module 1.

In the 1 The battery 1 shown also has a control unit 5, which is connected to each of the battery modules 4. For this purpose, each battery module 4 has a control connection 6. As already described, the control unit 5 regulates the operation of the high-voltage battery 1.

In the 1 The battery modules 4 shown are shown in their basic form. In order to increase the energy content of the battery 1, the battery modules 4 can be extended by an additional module 40. This embodiment is shown in 2 shown. As shown, the additional module 40 has only one arrangement of battery cells 42. The additional module 40 can be electrically connected to the battery module 4 via a direct electrical DC connection via corresponding connections.

3 illustrates the electrical and mechanical connection between the battery modules 4. For simplicity, only two battery modules 4 are shown, which are connected to one another in a series circuit. The holding rails 8 form a stable mechanical structure, which in the example shown has a ladder structure.

The holding rails running horizontally in the figure correspond to first holding rails 80 and run through grooves 47, which in the example shown are each arranged on one side - here the underside - of the battery modules 4. The horizontal holding rails 80 are connected at connection points to the vertically running holding rails, which correspond to the second holding rails. As a whole, the first holding rails 80 and second holding rails 81 form a kind of shelf-like holding frame. The connection structure shown is exemplary and can be expanded by providing further connection points, for example by a battery module 4 connected in parallel to each of the battery modules 4. The first holding rails 80 can have a shape in the area of the battery modules 4 that can be inserted into the grooves 47 to fit, so that there is a positive connection between them. If necessary, the battery modules 4 can be fastened to the holding rails 80 by additional means, for example by means of screw connections or plates which are screwed onto the battery modules 4 placed on the first holding rails 80, so that the first holding rails 80 are enclosed in the grooves 47.

The electrical connection structure actually formed by the first and second support rails 80, 81 is illustrated by the dashed lines 7. As already indicated, additional electrical connection pieces (in 3 not explicitly shown) can be used to implement the desired interconnection of the battery modules. In the example shown, for example, an electrical connection can be implemented in accordance with the electrical connection between the lower and upper battery modules 4 indicated by the dashed line 7. For this purpose, for example, an additional electrical line can be provided between the connection point of the lower right first holding rail 80 and the front right second holding rail 81 and between the connection point of the lower left first holding rail 80 and the front left second holding rail 81. In this way, opposing poles of the two battery modules 4 can be electrically connected to one another. This additional electrical line can generally be designed like the first and second holding rails 80, 81, but is usually shorter, and thus contributes to the mechanical stability of the holding frame structure. Alternatively, this additional electrical connection can be provided between the front left and the front right holding rail 81 in the middle between the connection points just described, in which case the second holding rails 81 can then have appropriately dimensioned electrically conductive sections. These required electrically conductive sections can be implemented, for example, by means of an electrically conductive core inside the second holding rails 81, which extends over a suitable length. For this purpose, the second holding rails 81 can be preconfigured with correspondingly conductive sections when designing the holding frame. The first and second holding rails 80, 81 can, for example, have an electically insulating plastic overmolding, so that the electrically insulating plastic overmolding can be removed at a suitable location for electrical contact with a conductive section of a second holding rail 81.

As already mentioned 3 As can be seen, a defective battery module 4 can be replaced very easily by removing it from the first retaining rails 80.

Examples of how the connection between a battery module 4 and the first support rails 80 can be designed are shown in 4A and 4B Here, a front view of a battery module 4 is shown, approximately diagonally from bottom to top right on the 3 shown structure, whereby only the right half of the module housing 43 is shown here and only one groove 47 is considered. Furthermore, in each of the battery housings 43, the internal busbar 44 is shown, by means of which the battery cells 42 within the battery modules 4 are electrically coupled to one another in a desired configuration.

In 4A a part of the base 45 within the groove 47 is flexible in such a way that it can be displaced into the module housing 43 when pressure is applied to it, for example by the first holding rail 80. For this purpose, the parts of the base 45 are mounted on springs 46, which are pressed together when pressure is applied, for example when the cell module 4 is attached to the first holding rail 80. This exposes the busbar 44 and can be brought into contact with the first holding rail 80. The parts of the base 45 of the groove 47 that can be displaced into the interior of the battery module 4 represent contact protection, since the busbar 44 is only exposed from its recess when pressure is applied to the base of the groove 47.

In 4B another possibility is shown in which the bottom of the groove 47 is fixed. In this embodiment, the electrical contact between the busbar 44 and the first retaining plate 80 is made by a screw 9 which is screwed into the module housing 43. For this purpose, through-openings which have an internal thread can be provided in the module housing 43.

Using the battery modules 4 according to the invention, high-voltage batteries can be constructed which can be optimized as required through scalability and modularity. For example, the structure can be adapted to different voltage levels and power classes. For example, the ratio of peak power to continuous power can be adjusted.

In addition, the battery modules with the integrated multi-stage converter ensure that there is no voltage at the voltage poles when switched off. This in turn results in improved maintainability, as the battery modules can be replaced very easily (in principle like light bulbs in a household). This results in improved service options and a reduction in warranty and goodwill costs can be achieved.

Furthermore, the intuitively simple design, including contact protection on the battery modules, enables the installation or replacement of the battery modules without an electrician, so that electrically trained persons can carry out installation or maintenance work.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 102011004248 A1 [0005]
• DE 102012212556 A1 [0006]
• DE 102013215572 A1 [0007]

Claims (10)

Battery module (4) for a high-voltage battery (1), comprising: a module housing (43) in which a bidirectional multi-stage converter (41) and a number of battery cells (42) are arranged, wherein these are electrically connected to one another by means of a busbar (44); wherein the module housing (43) has a first and a second open groove (47) for receiving a holding rail (80) which also functions as an electrical line. Battery module (4) according to Claim 1 , wherein a part of the busbar (44) crosses the first groove (47) or is arranged above it in a plan view of the battery module (4) and a further part of the busbar (44) crosses the second groove (8) or is arranged above it in the plan view. Battery module (4) according to Claim 2 , wherein the two grooves (47) are formed parallel to each other. Battery module (4) according to one of the Claims 1 until 3 , wherein both grooves (47) are arranged in the same side surface of the module housing (43). Battery module (4) according to one of the Claims 1 until 4 , wherein in at least one of the grooves (47) the part of the busbar (44) which crosses or overlaps this in plan view is exposed in the groove (47) and is set back into the interior of the module housing (43) relative to a bottom (45) of the groove (47). Battery module (4) according to Claim 5 , wherein at least a part of the bottom (45) of the groove (47) can be displaced into the interior of the module housing (43) when force is applied thereto. Battery module (4) according to Claim 5 , wherein in at least one of the grooves (47) in the overlap region of the busbar (44) with the groove (47) a through opening through the housing module (43) is provided. Battery module (4) according to one of the Claims 1 until 7 , further comprising: a first connection and a second connection, by means of which an additional module (40) containing battery cells (42) can be coupled to the battery module (4). High-voltage battery (1), comprising: at least two battery modules (4) according to one of the preceding claims, wherein these are fastened to one another by means of holding rails (80, 81) and electrically connected to one another. High-voltage battery (1) according to Claim 9 , wherein the high-voltage battery (1) further comprises a control unit (5) which is electrically coupled to each of the battery modules (4).

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