WO2024022824A1

WO2024022824A1 - High-voltage accumulator for a motor vehicle, and motor vehicle

Info

Publication number: WO2024022824A1
Application number: PCT/EP2023/069350
Authority: WO
Inventors: Raimund KOERVER; Malte Finger; Jose Lopez de Arroyabe
Original assignee: Bayerische Motoren Werke Aktiengesellschaft
Priority date: 2022-07-26
Filing date: 2023-07-12
Publication date: 2024-02-01
Also published as: DE102022118702A1

Abstract

The invention relates to a high-voltage accumulator (1) for a motor vehicle, having a battery element (2) which comprises a number of cell stacks (3) which are connected in series and each of which has a number of solid-state cells (4) which each comprise a cathode (5) of a bipolar electrode (6) and an anode (7) of a further bipolar electrode (6) and a solid-state electrolyte (8) is arranged between these two bipolar electrodes (6) and the solid-state cells (4) of the respective cell stack (3) are interconnected in parallel and at least two of the cell stacks (3) are welded into a pouch foil (9) together, wherein a voltage-tapping element (10) is arranged on the respective cell stack (3), each voltage-tapping element being connected to a controller device (11) arranged inside the pouch foil (9) and forming a battery management system (12) with the controller device, at least one cell voltage of the respective solid-state cell (4) being able to be detected by the battery management system, wherein the voltage-tapping elements (10) are arranged entirely in the pouch foil (9) together with the controller device (11). The invention also relates to a motor vehicle.

Description

High-voltage storage for a motor vehicle and high-voltage storage

The invention relates to a high-voltage storage device for a motor vehicle and a motor vehicle.

Batteries, in particular lithium-ion batteries, can be used to drive an at least partially electrically driven motor vehicle. To achieve the required voltage, individual battery cells are linked together in a combination of multiple parallel connections and a series connection. Cell stacks are formed from individual battery cells, which are connected to form modules in a high-voltage storage system. The individual cells, which are connected to each other by a cell contact system, are monitored by an external battery management system.

Solid-state batteries (all solid-state batteries, ASSB for short) represent a further development of lithium-ion batteries. A porous, liquid-soaked separator is replaced by a solid electrolyte. This solid electrolyte can comprise a ceramic, which can contain sulfides and/or oxides, and/or a solid-like polymer, which can also be in the form of a gel. Furthermore, a solid electrolyte can be integrated into the electrode, in particular to ensure lithium-ion conductivity within the electrodes. The solid electrolyte, as its name implies, has the property that it is not flowable.

Current high-voltage storage devices or batteries have the problem that the cells are individually coated, which leads to a particularly low energy density. Furthermore, a complex design is necessary, which enables low integration. When the cells are connected externally, the cabling takes up additional space in the high-voltage storage device, thus reducing the storage size and thus the range of the vehicle. In addition, modular control of the cell blocks in a battery management system has not yet been solved.

Furthermore, DE 10 2019 131 127 A1 shows a solid-state battery with two or more individual stacks stacked one above the other.

The object of the present invention is to provide a high-voltage storage device and a motor vehicle, in which a battery element of the high-voltage storage device can be designed to have a particularly small installation space in order to achieve a particularly to achieve high energy density, and also to provide advantageous cell monitoring.

This object is achieved according to the invention by the subject matter of the independent patent claims. Advantageous refinements and further developments of the invention are specified in the dependent patent claims as well as in the description and in the drawing.

A first aspect of the invention relates to a high-voltage storage device for a motor vehicle. The high-voltage storage device according to the invention has a battery element which comprises several, i.e. at least two, cell stacks connected in series, in particular serially bipolar, each of which has several, i.e. at least two, solid-state cells, each of which has a cathode or a cathode part of a bipolar electrode and an anode or an anode part of a further bipolar electrode and a solid electrolyte is arranged between the two bipolar electrodes, which separates the two bipolar electrodes, and the solid cells of the respective cell stack are connected in parallel with one another and the cell stacks or at least two of the cell stacks are welded together in a pouch film, whereby on the A voltage tapping element is arranged in each cell stack, which is each connected to a control device arranged within the pouch film and with this forms a battery management, through which at least one cell voltage of the respective cell stack can be detected, the voltage tapping elements being arranged together with the control device, in particular completely in the pouch film .

In other words, a battery element for a high-voltage storage device is proposed which has solid cells in a bipolar arrangement, with several of the solid cells being connected in a parallel arrangement to form a stack. At least two of the cell stacks, in particular all of the cell stacks present, are then connected in series in a bipolar manner. With a cell voltage of around 2 volts, for example, one possibility would be to connect 100 cells in parallel and to connect 12 cell stacks in series or serially bipolar in order to obtain a voltage below 60 volts, for example. The voltage taps are brought together at the cell stack level and connected within the pouch film to a microchip - a cell battery management system.

The high-voltage storage device according to the invention results in several advantages. On the one hand, the battery element can be made particularly compact and at the same time A highly integrative design can be realized. Furthermore, a simplification of the high-voltage battery and a wiring harness can be achieved. In addition, due to the savings in installation space, an increased energy density of the high-voltage storage device can be achieved. Due to the use of the solid cells, it is possible, for example, to form particularly thick cells, so that further peripherals, for example additional voltage tapping elements, can be saved. A further advantage is that a particularly flexible cell design is made possible, whereby, for example, the thickness of the layers in the structure of the battery element can be freely selected. Furthermore, the cell assembly, i.e. the battery element, which is essentially completely embedded in the pouch film except for contact elements or pole connections, can be designed as an “intelligent component” because it has a control device which forms at least a simple battery management system. This results in a certain modularity, so that the high-voltage storage device can, for example, be flexibly formed from several battery elements. Due to a saving in material, in particular copper and/or aluminum, and/or a reduction in production costs, the high-voltage storage device can also be provided at a particularly reduced cost. Another advantage is a reduction in heat losses, as simplified cell contact and material reduction reduce heat losses.

Below, among other things, three spatial arrangements of the voltage tapping elements and thus advantageous embodiments of the battery element are presented.

In an advantageous embodiment of the invention, the respective voltage tapping element leads from the respective cell stack to a surface of an external cell stack on which the pouch film rests and which is different from an exit surface, i.e. a side of the battery element on which a contact element or a pole is designed, and there meets a junction or is connected to it, which connects the voltage tapping elements to the control device, which is also arranged between the surface and the pouch film, the voltage tapping elements being arranged essentially transversely to the longitudinal direction of the battery element. The combination is, for example, a type of cabling or cable harness. “Substantially transverse to the longitudinal direction” means that a deviation from the longitudinal direction, for example by up to 30 degrees and in particular up to 10 degrees, is made possible. In other words, voltage taps are transverse to the Longitudinal extension direction, for example upwards, is guided, connected there and connected, for example by means of a thin flexible circuit board, to the control device, which is designed in particular as a chip. This results in the advantage that a geometric requirement of the battery element or the high-voltage storage can be responded to in a particularly advantageous manner by appropriately guiding the voltage taps.

In a further advantageous embodiment of the invention, the respective voltage tapping element is guided by the respective cell stack on an edge side of the respective cell stack and there meets a further junction which connects the voltage tapping elements with the control device, which is arranged on a head side or the exit surface of the battery element. The edge side is, for example, one of the surfaces of the respective cell stack, which lies transversely to its longitudinal direction and, furthermore, in particular on a short side and therefore does not correspond to the previously presented surface. In other words, the voltage tapping elements are brought together at one edge of the battery element. This assembly, which is designed in particular as a cable harness or electrical contact for connection to the control device, is oriented along the longitudinal direction towards the head side, the side of the battery element on which a pole emerges from the pouch film. The control device is arranged on this head side. This results in the advantage that geometric or installation space-related requirements of the high-voltage storage device can be responded to in a particularly advantageous manner.

In a further advantageous embodiment of the invention, the respective voltage tapping element leads from the respective cell stack to a surface of an external cell stack, on which the pouch film rests and which is different from the exit surface or the head side, and there meets a junction or is connected to it, which in particular electrically connects the voltage tapping elements to the control device, which is arranged on the head side, wherein the voltage tapping elements are arranged essentially along the longitudinal direction of the battery element. In other words, the voltage taps are brought together at the edge and from there guided to the control device at the head of the battery by means of the thin junction. “Substantially along the longitudinal direction” means that a deviation of up to 30 degrees is possible, and in particular a deviation of up to 10 degrees can be realized. Through the presented orientation The voltage tapping elements and the control device also have the advantage that the installation space of the battery element can be adapted in a particularly advantageous manner.

In a further advantageous embodiment of the invention, at least one of the voltage tapping elements and/or the control device and/or the assembly are at least partially formed by a flexible circuit board. In other words, an electrically usable material is used whose shape can at least be bent. For example, there are PCBs that are printed on an elastic material, such as a plastic film, and can be deformed at least in certain areas. If the voltage tapping elements and/or at least one of the voltage tapping elements, the control device and/or the combination are formed wirelessly in this way, the advantage is that the installation space of the battery element can be made particularly compact. In this way, a particularly flexible adaptation to geometric requirements and/or a particularly high energy density can be achieved.

In a further advantageous embodiment, the control device has a communication device which can be operated in a wired and/or wireless manner, in particular by means of radio. In other words, the control device has a communication port, which represents an interface for data exchange, for example with a control device of the motor vehicle. The data exchange can take place via cable using at least one line. Additionally or alternatively, the data exchange can take place wirelessly and/or wirelessly via radio, for example using WLAN, Bluetooth, RFID or the like. This has the advantage that particularly advantageous monitoring of the high-voltage storage unit is made possible.

In a further advantageous embodiment of the invention, the respective solid cell is cuboid and/or prismatic. In other words, the respective solid cell has the shape of a cuboid or a prism. This results in the advantage that a design of the battery element with little installation space is made possible in a particularly advantageous manner.

In a further advantageous embodiment of the invention, the exit surface or the respective head side, on which a connection element or a pole emerges from the pouch film, is arranged on a weld seam of the pouch film. In other words, the connection elements or Contacts are formed in particular directly on the weld seam, so that, for example, when welding two film halves, they are placed between them and thus form the exit from the pouch film. This therefore has the advantage that, for example, no extra opening has to be provided in the pouch film, whereby the battery element can be designed to be particularly robust, for example.

In a further advantageous embodiment of the invention, at least one of the solid cells is designed to be double-sided. The further cathode or anode can in particular form a part of a further adjacent solid cell. This is possible, for example, due to the design of the respective electrode as a bipolar electrode. In this way, the parallel connection of several solid-state cells is made possible in a particularly advantageous manner, in particular without the need for a separate casing for the respective solid-state cell, due to the properties of the bipolar electrode in combination with the solid-state electrolyte. Additionally or alternatively, the respective bipolar electrode can have both an anode and a cathode for series connection, for example, so that series connection can be implemented particularly advantageously. This results in the advantage that the battery can be designed to take up particularly little space.

A second aspect of the invention relates to a motor vehicle. The motor vehicle according to the invention comprises a high-voltage storage device according to the first aspect of the invention.

Advantageous refinements and developments of the first aspect of the invention are to be viewed as advantageous refinements and developments of the second aspect of the invention and vice versa.

Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and/or shown in the figures alone can be used not only in the combination specified in each case, but also in other combinations or on their own.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawings. It shows: Fig. 1 schematic view of a cell stack of a battery element

High-voltage storage for a motor vehicle;

2 shows a schematic view of a further embodiment of the cell stack;

Fig. 3 schematic view of an embodiment of the battery element

High-voltage storage with a battery management system;

Fig. 4 schematic view of a second embodiment of the

Battery element of the high-voltage storage unit with the battery management system; and

Fig. 5 schematic view of a third embodiment of the

Battery element of the high-voltage storage unit with the battery management system.

High-voltage storage devices are used to drive an at least partially electrically powered motor vehicle. Lithium-ion batteries in particular are used. A further development of a lithium-ion battery is a so-called solid-state battery, in which solid electrolytes can be combined with bipolar electrodes, for example. This enables the possibility of a so-called bipolar connection, whereby individual cell units can be connected in series and must be housed separately in them.

A high-voltage storage device 1, which can be used to drive the motor vehicle, will be presented below using the figures. This comprises a battery element 2, which comprises several, i.e. at least two, cell stacks 3 connected in series in a bipolar manner. 1 shows a schematic view of a first embodiment of such a cell stack 3. The cell stack 3 has several or at least two solid cells 4, each of which has a cathode 5 of a bipolar electrode 6 and an anode 7 of a further bipolar electrode 6, which is provided by a Solid electrolyte 8 is separated from the bipolar electrode 6, wherein the solid cells 4 of the respective cell stack 3 are connected in parallel. At least two of the cell stacks 3 are welded together in a pouch film 9, with a voltage tapping element 10 being arranged on the respective cell stack 3, which is each connected to a control device 11 arranged within the pouch film 9 and with this forms a battery management system 12, through which at least one cell voltage of the respective cell stack 3 can be detected, the voltage elements 10 being arranged completely in the pouch film 9 together with the control device 11.

The solid electrolyte 8, for example, itself forms a separator or is at least partially arranged in a separator. The respective bipolar electrode 6 can have an arrester 19, which is arranged between the two anodes 7 or cathodes 5 or between an anode 7 and cathode 5 in an alternative embodiment.

1 thus shows a possible embodiment of a respective cell stack 3.

The embodiment of FIG. 1 shows a possible embodiment of a cell stack 3, which in the exemplary embodiment is composed of two solid cells 4, for example. The embodiment of the cell stack 3 according to FIG. 1 is used for the two exemplary embodiments according to FIGS. 3 and 4.

FIG. 2 shows an analogous structure of a cell stack 3, but in an alternative geometric arrangement, which is used for the design of the exemplary embodiment according to FIG. 5.

By using the bipolar electrode 6, the respective cathode 5 and/or the anode 7 of a respective solid cell 4 can be designed to be double-sided.

The respective battery element 2 of FIGS. 3 to 5 each comprises two connection elements 13, one of which forms the positive pole and the other the negative pole of the cell stacks 3 connected in series, in particular serially bipolar, the connection being indicated by the connecting lines between the cell stacks 3 . The connecting elements 13 in particular leave the pouch film 9 in opposite directions, which applies to the exemplary embodiments according to FIGS. 3 to 5. The respective area at which the connection elements 13 leave the cell can be designed as an exit surface 14.

The first exemplary embodiment shown in FIG. 3 is designed in such a way that the respective voltage tapping element 10 extends from the respective cell stack 3 to a surface 15 of an external cell stack 3, against which the pouch film 9 rests and which is different from the exit surface 14. led and there on one Merger 16 meets, which connects the voltage tapping elements 10 with the control device 11, which is also arranged between the surface 15 and the pouch film 9, the voltage tapping elements 10 being arranged essentially transversely to the longitudinal direction of the battery element 2.

4 shows a schematic view of the second exemplary embodiment of the battery element 2, in which the respective voltage tapping element 10 is guided by the respective cell stack 3 on an edge side of the respective cell stack 3 and meets a further junction 16, which connects the voltage tapping elements 10 with the Control device 11 connects, the control device 11 being arranged on a head side, the positive pole, of the battery element 2.

Alternatively, Fig. 5 shows the third exemplary embodiment, whereby a cell stack according to Fig. 2 is used, with the respective voltage tapping element 10 from the respective cell stack 3 to a surface of an external cell stack 3, on which the pouch film 9 rests and which from the exit surface 14 is different, leads, and there meets a junction 16, which connects the voltage tapping elements 10 with the control device 11, which is arranged on the head side, the voltage tapping elements 10 being arranged essentially along the longitudinal direction of the battery element 2. The longitudinal extension direction is the direction in which the battery element 2 has the longest extension, in particular in the case of a substantially cuboid design, with length, width and height, the length coinciding with the longitudinal extension direction.

Advantageously, the at least one voltage tapping element 10 and/or the control device 11 and/or the junction 16 is at least partially formed by a flexible circuit board. Furthermore, it is advantageous if the respective solid cell 4 is cuboid and/or prismatic. The respective control device 11 advantageously has a communication device or is designed with this for wired and/or wireless exchange, for example communication ports 17 are provided.

For a particularly stable design, the head side and/or the exit surface 14, on which the connection elements 13 emerge from the pouch film 9, the connection elements 13 are arranged on a weld seam 18 of the pouch film 9. Furthermore, a motor vehicle is presented which includes a high-voltage storage device 1 according to one of the embodiments shown.

The high-voltage storage device 1 presented results in numerous advantages: For example, a particularly space-saving design can be implemented. Furthermore, a highly integrative design results. This results in higher energy densities and the battery element 2 or the high-voltage storage device 1 can be particularly advantageously adapted to the required geometric properties. In addition, the battery element 2 can be operated in particular as an intelligent component, which results in a certain modularity. A particularly advantageous bipolar ASSB pouch cell is presented here.

Reference symbol list

High-voltage storage battery element cell stack solid cell cathode

Bipolar electrode anode

Solid electrolyte pouch film

Voltage tapping element Control device Battery management system Connection element Exit surface Surface

Merging communication port weld seam arrester

Claims

Claims High-voltage storage (1) for a motor vehicle, with a battery element (2), which comprises several series-connected cell stacks (3), each of which has several solid cells (4), each of which has a cathode (5) of a bipolar electrode (6) and a Anode (7) of a further bipolar electrode (6) and between these two bipolar electrodes (6) a solid electrolyte (8) is arranged, which separates the two bipolar electrodes (6), and the solid cells (4) of the respective cell stack (3) parallel to one another are connected and at least two of the cell stacks (3) are welded together in a pouch film (9), a voltage tapping element (10) being arranged on the respective cell stack (3), each with a control device (11) arranged within the pouch film (9). ) is connected and with this forms a battery management system (12), through which at least one cell voltage of the respective cell stack (3) can be detected, the voltage tapping elements (10) being arranged together with the control device (11) completely in the pouch film (9). High-voltage storage device according to claim 1, characterized in that the respective voltage tapping element (10) from the respective cell stack (3) to a surface (15) of an external cell stack (3), against which the pouch film (9) rests and which from an exit surface (14 ) is different, leads and is connected there to a junction (16), which connects the voltage tapping elements (10) to the controller device (11), which is arranged between the surface (15) and the pouch film (9), the voltage tapping elements ( 10) are arranged essentially transversely to the longitudinal direction of the battery element (2). High-voltage storage (1) according to claim 1 or 2, characterized in that the respective voltage tapping element (10) is guided to an edge side of the respective cell stack (3) and meets a further junction (16) there, which connects the voltage tapping elements (10) to the controller device (11), which is arranged on a head side of the battery element (2). High-voltage storage (1) according to one of the preceding claims, characterized in that the respective voltage tapping element (10) from the respective cell stack (3) to a surface of an external cell stack (3) on which the pouch film (9) rests and which from an exit surface (14) is different, leads and is connected there to a junction (16), which connects the voltage tapping elements (10) to the controller device (11), which is arranged on the head side, the voltage tapping elements (10) essentially along the longitudinal direction of the battery element (2) are arranged. High-voltage storage (1) according to one of the preceding claims, characterized in that at least one of the voltage tapping elements (10) and/or the controller device (11) and/or the junction (16) are at least partially formed by a flexible circuit board. High-voltage storage device (1) according to one of the preceding claims, characterized in that the controller device (11) has a communication device which can be operated in a wired and/or wireless manner. High-voltage storage (1) according to one of the preceding claims, characterized in that the respective solid cell (4) is cuboid and/or prismatic. High-voltage storage device (1) according to one of the preceding claims, characterized in that the head side and/or the exit surface (14), on which a connecting element (13) emerges from the pouch film (9), is arranged on a weld seam of the pouch film (9). . High-voltage storage (1) according to one of the preceding claims, characterized in that the cathode (5) and/or anode (7) of at least one of the solid cells (4) is designed on both sides. Motor vehicle which has a high-voltage storage device (1) according to one of the preceding claims.