Battery system

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] Battery system

[0002] The invention relates to a battery system, a control unit for a battery system and a control method for a battery system.

[0003] With the progressive expansion of electromobility and battery and accumulator technologies in general, the issues of extending the lifespan of battery packs and their second life are becoming increasingly important. Most battery concepts today are essentially modular and based on individual battery cells that, when interconnected, form a complete storage unit for electrical power. For warranty reasons, particularly in the automotive sector, the entire battery storage unit is often replaced. This usually occurs due to declining overall performance, but regardless of whether individual battery cells are still usable. Many of the battery cells can still be used for various applications if they are in sufficient condition.

[0004] During a second life cycle, or in some cases even during the first use, individual battery cells may experience a decline in performance due to their progressive use, particularly towards the end of their normal service life. In principle, it is possible to replace individual defective battery cells in this case. However, with existing battery systems, this is associated with considerable effort and requires a high level of expertise. Battery cells are often welded to form contacts and can therefore only be separated with considerable effort. This is particularly disadvantageous because it not only makes battery cell replacement difficult, but also complicates their recycling.

[0005] It is an object of the present invention to provide a battery system, a control unit for a battery system, a control unit for a battery system and a control method for a battery system, whereby the replacement of battery cells is facilitated.

[0006] This object is achieved by a battery system according to patent claim 1, a control unit according to patent claim 10, and a control method according to patent claim 12. The battery system mentioned at the outset has a plurality of battery cells and a first circuit board. A number of conductive and preferably ferromagnetic elements are arranged on or in the first circuit board. A magnet is also arranged between a number of battery cells and a ferromagnetic element in such a way that its magnetic force holds the respective battery cell to the first circuit board, in particular to the conductive and preferably ferromagnetic element, at least in a direction towards the first circuit board. In addition, the magnet establishes an electrically conductive connection, in other words in particular a power contact, between a pole of the respective battery cells and the first circuit board.

[0007] In this application, the terms “battery” and “accumulator” are used synonymously, even though in common usage a distinction is sometimes made between non-rechargeable “batteries” and multiply rechargeable “accumulators” or “accumulators”.

[0008] In addition to the plurality of battery cells and the components described below, the battery system can also comprise further components, as described in detail below. The battery cells are, for example, cylindrical battery cells, e.g., type 21700. In principle, however, they can also be prismatic or other battery cells. In particular, they have an anode, a cathode, and an electrolyte, which together enable energy storage and release. In the context of the present application, the term "battery cell" also includes supercapacitors (supercaps) of any shape, which can be used alternatively or in addition to "conventional" rechargeable batteries. For electrical contact, a battery cell has, in particular, at least two poles, namely a + pole and a - pole. In particular, the battery cells are ferromagnetic and are therefore attracted to magnets.

[0009] In the present application, the term "plurality" means that the corresponding element is present more than once. In contrast, the term "number" means that the corresponding element is present one or more times.

[0010] The conductive and preferably ferromagnetic elements are, for example, firmly attached to the first circuit board (hereinafter also referred to as the base circuit board), e.g., soldered or conductively bonded. Further attachment methods are described in more detail below. Alternatively, the conductive and preferably ferromagnetic elements are incorporated directly into the circuit board. This can be done cost-effectively, for example, directly during circuit board production. The circuit board is then preferably designed as a thick-film circuit board in order to be able to handle the currents that occur. A circuit board is generally a printed circuit board (PCB), i.e., a carrier for electronic components that serves for their mechanical attachment and electrical connection.

[0011] A copper track or copper plate shaped as required can easily serve as the conductive element. The conductive elements are preferably also ferromagnetic. The conductive and ferromagnetic elements comprise a material in which the atomic magnetic moments preferentially align in parallel. They therefore have a permanent magnetic field themselves or are preferentially strongly attracted to the pole of an external magnetic field. They can be designed, for example, as iron or steel plates. Furthermore, they can be designed and shaped, for example, to establish electrically conductive contact with one or more magnets connected to the battery cells. Depending on the shape of the ferromagnetic elements, several battery cells can be interconnected.

[0012] The electrically conductive connection between the base circuit board or the conductive and preferably ferromagnetic element arranged on or within it and the battery cell is established via the magnet. The magnet therefore acts primarily as a power contact. The magnet can be a strong permanent magnet, particularly a permanent magnet with a magnetic coercive field strength of >500 A / m, for example, a neodymium-iron-boron magnet (neodymium magnet for short).

[0013] In addition, the magnet exerts a magnetic force that acts on one part of the battery cell, in particular on one pole, and on the other on the ferromagnetic element. As a result, the magnet holds the battery cell to the base circuit board, and in particular to the ferromagnetic element, in a direction toward the base circuit board.

[0014] The magnet thus serves a dual function: firstly, as a magnetic holder for the battery cell, and secondly, as a power contact to the battery cell. The ferromagnetic element also serves a dual function: firstly, as a counterholder for the magnet for mechanical attachment to the base circuit board, and secondly, as an element for interconnecting – particularly for parallel connection – the individual battery cells. This makes it possible to arrange the individual battery cells close to the base circuit board and connect them to it using as few additional components as possible. The overall battery system is therefore advantageously particularly weight-efficient, space-efficient, and, due to the elimination of additional components, also cost-effective.

[0015] The shape of the base circuit board, the arrangement of the battery cells and their interconnection, in particular by means of the conductive and preferably ferromagnetic elements, are preferably adapted to the respective application in their design.

[0016] The control unit mentioned above serves to control the battery system according to the invention. It monitors the states of the individual battery cells and switches them on accordingly. Alternatively or additionally, it issues a corresponding warning signal.

[0017] To monitor the status of individual battery cells, the control unit can, for example, analyze parameters such as voltage, current, or the like to determine whether they are within specified value ranges. In particular, the temperature of the battery cells is also analyzed, as described in more detail below.

[0018] The battery cells are switched, for example, by means of a further, second circuit board, i.e., a control board, which is preferably arranged on the side of the battery cells opposite the base circuit board. The switching is carried out, for example, by means of a relay or transistor. The battery cells can in principle be switched individually; however, the switching is preferably carried out for a group of battery cells, in which the battery cells are particularly preferably connected in parallel.

[0019] For example, if it is determined that the condition of a battery cell is outside the permissible range, the battery cell or group of battery cells can be isolated or switched off from the power circuit so that harmful consequences in the event of a malfunction of the possibly affected battery cell can be avoided or at least reduced.

[0020] The warning signal can be implemented acoustically, for example, as a warning tone, warning announcement, or the like. Alternatively or additionally, the warning signal can be implemented visually, for example, as a warning light, warning LED, display, or the like. As already described, fundamentally different parameters can be used to analyze the condition of a battery cell. However, the temperature of the battery cell is particularly meaningful in this regard. Accordingly, in the control method mentioned above for a battery system according to the invention, individual battery cells are checked to determine whether their temperature lies within a defined range.

[0021] The defined temperature range can, for example, be a fixed value range. Alternatively, it can also be adjusted to the ambient temperature or defined as a range around an average temperature of a number of battery cells.

[0022] The invention can be implemented in particular in the form of a computer unit with suitable software. For this purpose, the computer unit can, for example, have one or more cooperating microprocessors or the like. In particular, it can be implemented in the form of suitable software program parts in the computer unit. A largely software-based implementation has the advantage that even computer units already in use can be easily retrofitted by a software or firmware update in order to operate in the manner according to the invention. In this respect, the object is also achieved by a corresponding computer program product with a computer program that can be loaded directly into a memory device of a computer unit, with program sections in order to carry out all steps of the method according to the invention when the program is executed in the computer unit.Such a computer program product may, in addition to the computer program, include additional components such as documentation and / or additional components, including hardware components such as hardware keys (dongles, etc.) for using the software.

[0023] A computer-readable medium, for example a memory stick, a hard disk or another portable or permanently installed data storage device, on which the program sections of the computer program that can be read and executed by a computer unit are stored, can be used for transport to the computer unit and / or for storage on or in the computer unit.

[0024] Further, particularly advantageous embodiments and developments of the invention emerge from the dependent claims and the following description, wherein the claims of one claim category can also be developed analogously to the claims and description parts to form another claim category and, in particular, individual features of different embodiments or variants can be combined to form new embodiments or variants.

[0025] The battery system preferably comprises the control unit described above.

[0026] For a plurality of battery cells, a temperature element is preferably arranged on a circuit board, preferably on the base circuit board, and connected to the battery cell via the circuit board for temperature measurement. This is particularly preferably implemented for each of the battery cells.

[0027] The temperature sensor is preferably a thermistor, an electronic component whose resistance changes reproducibly with temperature. The temperature is determined or measured based on the change in resistance. Taking the temperature measurement into account, the condition of the battery cell is then analyzed. If necessary, the battery cell is shut down or deactivated, as described above, and / or a warning is issued.

[0028] Preferably, only one AD converter is used for a plurality of temperature elements. This is preferably implemented with a common AD converter for all temperature elements. Particularly preferably, the AD converter converts temperature signals from the temperature elements separately using multiplexing.

[0029] The temperature signals are digitized using the AD converter and then forwarded to the control unit. Multiplexing is performed, for example, using an FPGA. Multiplexing advantageously eliminates the need for AD converters and reduces the number of signal lines or conductor tracks on the base circuit board or on the circuit boards.

[0030] Preferably, a cell holder holds a plurality of the battery cells in a fixed position relative to one another in at least one lateral direction.

[0031] For this purpose, the cell holder is particularly preferably designed and shaped such that it encloses the battery cells in a substantially form-fitting manner in the lateral direction. This prevents any movement or slippage of the battery cells in this direction. The lateral direction refers to a direction or directions that extend parallel to the plane of the base circuit board, i.e., in the case of cylindrical battery cells, in particular the radial direction.

[0032] The magnets are preferably arranged on the first circuit board in a force-fitting and / or form-fitting manner by means of a fastening means. The fastening means is particularly preferably arranged partially in a through-hole that extends through the magnet, the conductive and preferably ferromagnetic element, and the first circuit board.

[0033] In principle, any suitable fastening means can be used. However, the fastening means is preferably a screw. The magnet particularly preferably has a countersunk recess into which the screw head is countersunk to prevent it from projecting beyond the surface of the magnet. The screw is particularly preferably screwed with a nut on the side of the first circuit board opposite the magnet. This firmly connects the magnet, the conductive and preferably ferromagnetic element, and the first circuit board.

[0034] The term "through-hole" is to be understood here based on the result and independent of the actual manufacturing process used. A through-hole essentially refers to a round hole that extends concentrically through the magnet, the conductive and preferably ferromagnetic element, and the first circuit board. This can be created, for example, during the production of the individual components or subsequently introduced into the respective component by drilling, laser cutting, milling, cutting, or similar methods.

[0035] In particular, if the magnet, the conductive element, and the first circuit board are connected by means of the fastening means, it is not necessary for the conductive element to be ferromagnetic at the same time. In this case, the electrical conductivity of the conductive element can be selected to be higher due to the wider range of materials available. For this purpose, the conductive element can, for example, comprise copper and, in particular, be made of copper.

[0036] The control unit is preferably designed so that a user can identify a damaged battery cell by means of the warning signal.

[0037] This can be achieved, for example, by displaying the location of the affected battery cell on a circuit board, by arranging LEDs adjacent to the battery cells on a circuit board, and by illuminating an LED associated with the affected battery cell, or in a similar manner. This advantageously allows the user to easily locate and replace the affected battery cell.

[0038] On a side of the battery cell opposite the base circuit board, the power contact to the battery cell is preferably established by means of an electrically conductive foil, which is particularly preferably pressed onto the corresponding pole of the battery cell by the magnetic force of another magnet. The electrically conductive foil can, for example, be a copper foil, preferably electroplated – e.g., with nickel, silver, or gold. This allows battery cells to be interconnected in a similar way to the conductive and preferably ferromagnetic elements. In particular, a group of battery cells can be connected in parallel between the conductive and preferably ferromagnetic elements and the conductive foil.

[0039] The conductive foil is also particularly preferably conductively connected to a second circuit board, also referred to below as the control board, by means of a contact element. The contact element is designed, for example, as an electrically conductive spacer bolt, which is preferably screwed to the copper foil and the control board. The spacer bolt also bridges the gap between the copper foil and the control board caused by the magnets.

[0040] This essentially results in the following sequence of layers in the battery system: base circuit board, conductive and preferably ferromagnetic element, magnet, battery cell, conductive foil, magnet, control board, wherein the conductive foil is electrically connected to the control board by means of a contact element.

[0041] On a side of the battery cells opposite the first circuit board, a power contact is made from at least one battery cell to the second circuit board, preferably by means of a magnetic grid with square magnets arranged in the grid. In such a magnetic grid, magnets arranged adjacent to one another at an edge particularly preferably have opposite magnetic polarities. The magnets comprise contact magnets, each of which is arranged adjacent to a battery cell, and optionally spacer magnets arranged between the contact magnets. A grid generally specifies a regular pattern with specific repeat spacing. The individual magnets of the magnetic grid are therefore square in shape with the dimensions of the grid squares. Their edges each border on a magnet with opposite polarity. This results in a quasi-checkerboard pattern of polarities.The adjacent magnets thus attract each other and, once aligned, form a self-retaining geometric shape. The geometric shape of the magnetic grid can be selected as needed during the battery system design, depending on the application, the overall geometry requirements, voltage requirements, and the current requirements to be provided.

[0042] In such a magnetic grid, for example, contact magnets, each arranged adjacent to a battery cell, and optionally spacer magnets, which are not arranged adjacent to the batteries but in the spaces between them, follow one another at the edges. In particular, the contact magnets and spacer magnets have opposite magnetic polarities.

[0043] Alternatively, the magnets can also be larger, for example. In this case, each magnet is arranged adjacent to a battery cell and thus acts as a contact magnet. Consequently, the battery cells are not all contacted with the same magnetic polarity; instead, adjacent magnets have opposite polarities. In this case, the previously described spacer magnets can be omitted.

[0044] In addition to the magnetic grid, an electrically conductive foil is preferably inserted between the magnets of the magnetic grid and the battery cells to improve conductivity, as already described above.

[0045] The magnets of the magnetic grid therefore contact the contacts of the battery cells either directly or are arranged adjacent to them, spaced only by the conductive foil. In particular, the magnets attached to the first circuit board and the opposing magnets of the magnetic grid have opposite polarities, so that a magnetic force of attraction is formed between them. Preferably, a plurality of battery cells are conductively connected to form a switching group by means of the conductive and preferably ferromagnetic elements, the electrically conductive foil and / or the magnetic grid. The individual battery cells are in particular connected in parallel and / or in series as such a switching group. As a result, the voltage provided can be selected as required when designing the battery system.The shape of the conductive and preferably ferromagnetic elements, the electrically conductive foil and / or the magnetic grid are essentially the same.

[0046] The battery system preferably comprises several switching groups of battery cells. At least one grid square of an insulator is arranged between two different switching groups of battery cells on a side opposite the first circuit board.

[0047] The insulator can, for example, be made as a holding frame made of a non-conductive material, such as plastic or the like. This has the advantage of holding the magnetic grids and, if applicable, the electrically conductive foil of the switching groups in a fixed position relative to the battery system. Spacing the individual switching groups in this way ensures that voltage breakdown between the switching groups is avoided.

[0048] In addition to any other components, the previously described control unit is preferably also arranged on the control board. The control unit is thus preferably encompassed by the control board and particularly preferably integrated on or into it. The control of the switchable power connection and, additionally or alternatively, the power connection for the entire battery system can preferably be arranged on the control board.

[0049] In the control method, the status of each battery cell is preferably determined. This is particularly preferably done using its temperature. Furthermore, the status of a number of battery cells is output or displayed in a color-coded representation of the battery system.

[0050] Color coding is preferably based on condition and particularly preferably using predefined temperature ranges. For example, a battery cell in poor condition is shown in red and characterized by temperatures above 80°C. A battery cell in average condition is shown in yellow and characterized by temperatures above 40°C and below 80°C. A battery cell in good condition is shown in green and characterized by temperatures below 40°C.

[0051] The output is provided, for example, via a suitable output interface of the control unit. The output interface is preferably wireless, e.g., as a WLAN interface or a Bluetooth interface. The output is forwarded via the output interface to a terminal device, in particular a mobile device such as a smartphone and / or tablet. There, a display shows, for example, a schematic model of the battery system with its battery cells, which are color-coded as described above.

[0052] The invention is explained in more detail below with reference to the accompanying figures using exemplary embodiments. In the various figures, identical components are provided with identical reference numerals. Where relative directions such as "above" or "below" are used below, these directions are to be understood as meaning that the base board or the first layer arrangement is arranged "below" and, relative to it, the control board or the second layer arrangement is arranged "above." The figures are generally not to scale. They show:

[0053] Figure 1 is a perspective view of an embodiment of a battery system according to the invention,

[0054] Figure 2 is a perspective view of the battery system from Figure 1 but without the control board,

[0055] Figure 3 is a perspective exploded view of a second layer arrangement of the battery system from Figure 1,

[0056] Figure 4 is a perspective view of a first layer arrangement of the battery system of Figure 1,

[0057] Figure 5 is a perspective exploded view of the first layer arrangement from Figure 4, Figure 6 is a plan view of a base board of the first layer arrangement from Figure 4 with applied conductive and preferably ferromagnetic elements,

[0058] Figure 7 is a flowchart of an embodiment of a control method according to the invention for a battery system according to the invention,

[0059] Figure 8 is a perspective view and partially exploded view of the side facing the battery cells of an alternative first layer arrangement of a further embodiment of a battery system according to the invention,

[0060] Figure 9 is a perspective view and partially exploded view of an alternative second layer arrangement with a magnetic grid of a further embodiment of a battery system according to the invention,

[0061] Figure 10 is a perspective detailed view of the contact between the second layer arrangement of Figure 10 and a second printed circuit board and

[0062] Figure 11 is a schematic plan view of a magnetic grid of the second layer arrangement from Figure 10.

[0063] Figures 1 to 6 show roughly schematically different views of an embodiment of a battery system 10 according to the invention. Figure 1 shows an overall view in perspective.

[0064] The battery system 10 comprises a first layer arrangement 50 and a second layer arrangement 60. The layer arrangements 50, 60 are spaced apart by spacer elements and are each screwed to them for fastening by means of a plurality of retaining screws 24. A plurality of battery cells 11 are arranged between the layer arrangements 50, 60. The battery cells 11 are, for example, cylindrical battery cells of the type 21700. The contacting of the battery cells 11 and the structure of the two layer arrangements 50, 60 will be described in more detail with reference to Figures 2 to 6.

[0065] The layers of the layer arrangements 50, 60 extend essentially in an x-y plane which is characterized by a first lateral direction RX and a second lateral direction RY. The first layer arrangement 50 comprises a first cell holder 25 and the second layer arrangement comprises a second cell holder 40. The cell holders 25, 40 each enclose the individual battery cells 11 around the circumference and thus essentially create a positive connection in the radial direction of the respective battery cell. This prevents movement of the battery cells 11 in the radial direction, i.e. also in the two lateral directions RX, RY. For this purpose, the cell holders 25, 40 are essentially designed as a perforated grid with circular cutouts or holes. The battery cells 11 are thus held in a fixed position relative to one another in the lateral direction RX, RY.However, the cell holders 25, 40 by themselves do not restrict movements of the battery cells 11 in a z-direction perpendicular to the lateral directions RX, RY.

[0066] The second layer arrangement 60 comprises a control board 31, which is also commonly referred to as a battery management system. The control board is a printed circuit board (PCB), i.e., a carrier for electronic components that serves for their mechanical attachment and electrical connection. Accordingly, numerous electronic components are installed on the control board 31, some of which will only be discussed in detail, since battery management systems are generally familiar to those skilled in the art.

[0067] Among other things, the control board 31 includes a main switch 37 for switching the battery system 10 on and off. It also includes a charging interface 39, which is designed, for example, as a D-Sub 9 connector. The charging interface 39 serves as a charging port for charging the battery system 10 and preferably also for communication with a connected external charger (not shown), e.g., via CAN bus.

[0068] The control board 31 further comprises a control unit 30, which is designed, for example, as a single-board computer or system-on-chip (SoC), in particular as a Raspberry Pi® Pico or RP2040. By means of the control unit 31, essential functions of the battery system 10 can be monitored and the battery system 10 can be controlled accordingly. The control unit 30 has a user interface 38, which is designed as an interface to suitable input means and / or display means, e.g., as a USB interface. By means of the user interface 38, basic functionalities and / or firmware can be loaded onto programmable components such as EEPROM, FPGA, and the like using a bootloader. In addition, relevant data of the battery system 10 can be output via this interface and / or external control signals for the battery system 10 can be received. A method for controlling the battery system is described in more detail with reference to Figure 7.

[0069] The control board 31 also comprises a second connecting plug 43, which points to a first connecting plug 26 of the first layer arrangement 50 and is arranged in alignment with the latter. The connecting plugs 26, 43 serve, on the one hand, for signal transmission between a base circuit board 12 of the first layer arrangement 50 and the control board 31, i.e., measurement signals and / or control signals are exchanged between the circuit boards 12, 31 via the individual lines of the connection using suitable cables. On the other hand, they also serve for balancing, i.e., for equalizing charge differences between individual cell groups. For this purpose, a cable, preferably a flexible ribbon cable (not shown here), which is designed to transmit both the signals and the balancing power, is inserted between the connecting plugs 26, 43.

[0070] For power transmission between the circuit boards 12, 31, power connectors 36 are arranged on both sides next to the connecting plugs 26, 43. The

[0071] Power connectors 36 of corresponding poles are arranged one above the other and connected in pairs by means of a cable (not shown here). The cable can, for example, be connected to the respective power connectors 36 on both sides with a material connection. Alternatively, it can be plugged onto a plug-in terminal by means of a flat receptacle, which is attached to the respective power connector 36, or it can be attached by means of a clamp, or the like.

[0072] Figure 1 also shows a number of contact screws 34, each of which establishes a power contact with the battery cells 11 at a contact point. From the respective contact point, the current provided by the battery cells is distributed via appropriately dimensioned conductor tracks on the control board 31 or routed to the power connectors 36. Additionally, a cell voltage measuring unit and / or a balancing device for charge equalization between cell groups can be connected via the conductor tracks.

[0073] To form the power or measuring contact, the control board 31 is screwed between the contact screw 34 and a contact element 33 (see Figure 2), which here is designed as an electrically conductive spacer bolt 33. On the side of the spacer bolt 33 opposite the control board, an electrically conductive foil 32 (see Figure 3) is inserted and screwed between the spacer bolt 33 and a counter element (not shown), such as a threaded bushing. The electrically conductive foil 32 is designed here as a copper foil 32. The copper foil 32 can be shaped as required, i.e. depending on the number and arrangement of the battery cells 11 to be contacted. For this purpose, it can be cut to size, for example, using laser cutting.

[0074] Figure 3 shows an exploded view of the second layer arrangement 60, in which a magnet 15 is arranged above a circular recess in the second cell holder 40 and above the respective copper foil 32. During normal operation, the magnet 15 presses the copper foil 32 onto a pole of the corresponding battery cell 11 arranged in a circular recess in the second cell holder 40. This is because the pole of the battery cell 11 comprises a ferromagnetic material, so that the pole of the battery cell 11 and the magnet 15 are magnetically attracted to each other. By means of the copper foil 32, the contact screw 34 and the contact element 33, an electrical power contact is thus established with the control board 31. Depending on the design or shape of the copper foil 32, a group of battery cells 11 can be connected in parallel. The shape of the copper foil can be adapted accordingly when designing the system, i.e.depending on the shape of the battery system 10 as a whole and depending on the required voltage and the like.

[0075] To hold the magnets 15 in their position in the lateral directions RX, RY, the second layer arrangement 60 further comprises a second magnet holder 41. Analogous to the cell holder 25, 40, the second magnet holder 41 is essentially designed as a perforated grid with circular recesses or holes. The size and position of the holes in the second magnet holder correspond to the size and positions of the magnets 15 in the second layer arrangement 60. The magnets 15 are generally arranged so as to be movable in the z-direction in the second magnet holder 41 so that they can bring the copper foil 32 into contact with the pole of the respective battery cell 11. The second layer arrangement 60 further comprises a damping or insulating layer 42 to dampen any movements of the magnets 15 in the second magnet holder 41.

[0076] Figure 4 shows a perspective view of the first layer arrangement 50. The first cell holder 25 of the first layer arrangement 50 is designed essentially analogously to the second cell holder 40 and is not shown for illustrative reasons. The basic shape of the first layer arrangement 50 essentially corresponds to the shape of the second layer arrangement 60. The first layer arrangement 50 comprises a first printed circuit board 12, which is also referred to as the base circuit board 12. Ferromagnetic elements 14 are materially bonded to the base circuit board 12. The ferromagnetic elements 14 are formed here, for example, from galvanized 1.0330 (D1) steel and soldered to the base circuit board 12 using a reflow soldering process. The ferromagnetic elements 14 are each shaped to match the corresponding copper foil 32 of the second layer arrangement 60.

[0077] A number of magnets 15 are arranged and positioned on the ferromagnetic elements 14, corresponding to the battery cells 11 to be contacted. The magnets 15 exert a magnetic force on the respective ferromagnetic pole of the associated battery cell 11 and thereby hold the battery cell 11 in position, particularly in the z-direction, i.e., in the direction perpendicular to the surface of the base circuit board 12, on the base circuit board or on the ferromagnetic element 14 directly connected to it. The magnets 15 can preferably be firmly attached to the ferromagnetic elements 14. This can be achieved, for example, by suitable bonding, provided that the electrical contact between the magnet 15 and the ferromagnetic element 14 is maintained.

[0078] The magnets 15, i.e. preferably all of the magnets, are designed here as nickel-plated neodymium magnets. Neodymium magnets are particularly advantageous due to their strong magnetic field. By means of the electrically conductive nickel layer, in particular a nickel-copper-nickel layer (Ni-Cu-Ni), the magnets 15 can act as electrical power contacts. This means that during operation, electrical current flows through them and conducts this from the respective battery cell 11 via the ferromagnetic element 14 to the base circuit board 12. From the respective contact point of the ferromagnetic element 14 with the base circuit board 12, the current provided by the battery cells 11 is distributed by means of suitably dimensioned conductor tracks and / or conducting surfaces on the base circuit board 12 or is conducted to the first connecting plug 26 and from there transmitted to the control board 31.

[0079] MOSFETs 18 for power control are also arranged on the base circuit board 12. The first layer arrangement 50 further comprises a spacer 27, which supports the positive connection between the cell holder 25 and the base circuit board 12. Figure 5 shows the first layer arrangement 50 in an exploded view. In addition, two converter boards 20 of the first layer arrangement 50 are shown here. The converter boards 20 each have a number of plug-in elements 23, which are inserted through positionally corresponding through-holes 19 (see Figure 6) of the base circuit board 12 and soldered there. An AD converter 21 and an integrated circuit 22 or an FPGA 22 are each arranged on the converter boards 20. The AD converter is designed to digitize analog measurement signals. The measurement signals originate from thermistors 17, i.e.temperature-sensitive resistors arranged on the base circuit board 12 and each spatially assigned to the magnet 15 of a battery cell 11. This is particularly evident in Figure 6 and is exemplified by a ferromagnetic element 14. The temperature of the respective battery cell 11 can thus be determined via the thermistors 17.

[0080] In this case, one AD converter is shared by several thermistors 17, with the integrated circuit 22 or FPGA 22 transmitting the incoming signals from the thermistors 17 in a sequential, time-resolved manner to the AD converter 21 and forwarding these time-resolved signals via the base circuit board 12 to the control board 31. Thus, a temporal multiplexing of the temperature signals occurs. This temperature measurement is preferably performed for each battery cell 11. This allows the control board 31 to determine the state of each battery cell 11 using the respective temperature.

[0081] The first layer arrangement 50 has a discharge terminal 35 (see Figure 1), which is arranged on the side of the base circuit board 12 opposite the battery cells 11. The discharge terminal 35 has a positive pole and a negative pole and can be designed, for example, as a connector (not shown here), in particular as an XT90 plug or socket. The power provided by the battery system 10 is transmitted to a load connected to it via the discharge terminal 35.

[0082] Figure 7 schematically illustrates an exemplary embodiment of the sequence of a control method according to the invention for a battery system according to the invention as a block diagram. In a first step I, the battery system 10 is put into operation.

[0083] In a further step 11a, a temperature is determined for each battery cell 11 as previously described. Furthermore, in a step 11b, a voltage is determined for each cell group, and in a step 11c, the charging and / or discharging currents of the entire battery system are determined.

[0084] In a further step III, the determined values ​​are transmitted to the control unit 30 of the control board 31 and analyzed together. The temperature, current, and voltage can vary for each battery cell 11 depending on the power drawn and the condition of the respective battery cell.

[0085] If the analysis reveals that the condition of a battery cell 11 is outside a predefined permissible range, the next steps IVa or IVb are performed for the battery cell 11. This is particularly the case if a permissible maximum temperature, for example, 80°C for Molicel P28A, is exceeded.

[0086] In step IVa, the respective battery cell 11 or the associated group of parallel-connected battery cells 11 is switched off in order to avoid further impairment and any resulting hazards.

[0087] In step IVb, a warning is issued by the control unit 30. This can be an acoustic signal, e.g., a warning tone or an announcement of the battery position. Alternatively or additionally, a visual warning can be issued, e.g., by means of a warning light or a corresponding indicator on a display. In addition, the user is preferably informed, e.g., by means of a display or an LED light locally assigned to the battery cell 11, which battery cell 11 is affected, so that they can locate and replace it as easily as possible.

[0088] Figure 8 shows a perspective view in a partially exploded view of the side facing the battery cells 11 of a further embodiment of the first layer arrangement 50', which is similar to the first layer arrangement 50 described with reference to Figures 4 to 6.

[0089] In contrast to the exemplary embodiment of Figures 4 to 6, however, in the first layer arrangement 50' shown here, the magnets 15' are screwed together with the conductive elements 14' and the first circuit board 12' or the base circuit board 12' in a form-fitting or force-fitting manner by means of a fastening screw 71 as the fastening means 71. For this purpose, the magnets 15', the conductive elements 14', and the base circuit board 12' have through-holes for the respective fastening screw 71. Therefore, it is no longer necessary for the conductive elements 14' to be applied to the base board 12' in a material-fitting manner. Nor do they need to have ferromagnetic properties, since the magnets 15' are also arranged in a fixed position on them by means of the fastening screw 71.

[0090] The fastening screws 71 are each screwed to the opposite side of the base plate 12' using fastening nuts 72. The magnets 15' each have a countersunk recess so that the heads of the fastening screws 71 do not protrude above the surface of the magnets 15' and a good power contact with the respective battery cell (not shown here) can be established. Additionally, cover disks 70, preferably ferromagnetic or magnetic, are arranged on the side of the magnets 15' facing the battery cells 11 to establish an even better power contact with the battery cell 11.

[0091] Since the battery cells are essentially ferromagnetic, their atomic magnetic moments always align in the direction of the magnetic field generated by the magnets 15, 15', so that an attraction occurs between the battery cell and the adjacent magnet 15, 15' or the adjacent magnets 15, 15'.

[0092] Figures 9 to 11 show perspective views (see Figures 9 and 10) and a schematic plan view (see Figure 11) of a further embodiment of the second layer arrangement 60', which is similar to the second layer arrangement 60 described with reference to Figures 2 and 3.

[0093] In contrast to the embodiment of Figures 2 and 3, however, in the second layer arrangement 60' shown here, no individual round magnets 15 are applied to the conductive foil 32 or copper foil 32, but rather a magnetic grid 73.

[0094] The magnets 74, 75 of the magnetic grid are square-shaped, with the dimensions of the grid squares. Their edges each border a magnet with opposite polarity, resulting in a checkerboard pattern of polarities (see Figure 11). The grid magnets 74, 75 comprise contact magnets 74, which are arranged adjacent to the battery cells 11, i.e., spaced apart by the copper foil 32, and spacer magnets 75, which bridge the distance between the battery cells 11. The contact magnets 74 thus each exert a magnetic force—also through the copper foil 32—on the adjacent battery cell 11, thus ensuring electrically conductive contact between the battery cell 11 and the copper foil 32 or the magnetic grid 73.

[0095] The adjacent contact magnets 74 and spacer magnets 75 thus attract each other and, once arranged next to each other, form a self-retaining geometric shape. The geometric shape of the magnetic grid 73 can be selected as needed depending on the application when designing the battery system 10', depending on the overall geometry requirements, voltage requirements, and the current requirements to be provided.

[0096] Several battery cells 11 are conductively connected to form a switching group 77 (see Figure 9) by means of the conductive elements 14', the copper foil 32, and / or the magnetic grid 73. The individual battery cells 11 are connected in parallel, in particular, as a switching group 73. This allows the provided voltage to be selected as needed when designing the battery system 50'. The shape or configuration of the conductive elements 14', the copper foil 32, and / or the magnetic grid 73 are essentially geometrically identical.

[0097] The battery system 50' here comprises nine switching groups 77 of battery cells 11. At least one grid square of an insulator 76, which is designed here as a plastic holder frame 76, is arranged between the switching groups 77 of battery cells 11 in the second layer arrangement 60'. It holds the magnetic grids 73 and, if applicable, the electrically conductive foil 32 of the switching groups 77 in a fixed position relative to the battery system 10'. The spacing of the individual switching groups 77 ensures that voltage breakdown between the switching groups 77 is avoided.

[0098] Figure 10 shows the contact between the magnetic grid 73 and the control board 31. The magnetic grid 73 is brought into electrically conductive contact by means of a round magnet 15', which, due to its polarity, holds onto the underlying contact magnet 74 of the magnetic grid 73. The magnet 15', like the magnets 15' on the base circuit board 12', is designed with a countersunk recess (not visible here) and is similarly fastened to the control board 31 by means of a fastening screw 71 and a fastening nut 72 that locks the screw. Due to the flexibility of the geometric adaptation of the conductive and preferably ferromagnetic elements as well as the magnetic grid, the described battery system according to the invention can advantageously be designed for each application as required with low redesign effort compared to known solutions.

[0099] Finally, it should be noted once again that the invention described in detail above merely represents exemplary embodiments which can be modified in a variety of ways by a person skilled in the art without departing from the scope of the invention. For example, a first layer arrangement was described with reference to Figure 8, in which the conductive elements are arranged on the circuit board. However, it is equally possible - particularly during production of the circuit board - to introduce the conductive elements directly into the circuit board. Furthermore, with reference to Figure 11 in particular, only a magnetic grid was described in which contact magnets and spacer magnets of different polarity alternate. However, it is equally possible to dimension the magnets of the magnetic grid such that each magnet in the grid contacts a battery cell, with the polarity of adjacent magnets continuing to alternate.Furthermore, the use of the indefinite articles "ein" and "eine" does not preclude the possibility that the relevant characteristics may be present multiple times. Likewise, terms such as "Einheit" do not preclude the relevant components from consisting of several interacting subcomponents, which may also be spatially distributed. Regardless of the grammatical gender of a particular term, this includes persons with male, female, or other gender identities.

[0100] List of reference symbols

[0101] 10, 10' battery system

[0102] 11 battery cells

[0103] 12 first circuit board, base circuit board

[0104] 14, 14' ferromagnetic element

[0105] 15, 15' magnet

[0106] 16 spacer element

[0107] 17 temperature element, thermistor

[0108] 18 MOSFET

[0109] 19 through holes

[0110] 20 converter board

[0111] 21 AD converters

[0112] 22 integrated circuits, FPGA

[0113] 23 plug-in element

[0114] 24 mounting screw

[0115] 25 first cell holder

[0116] 26 first connector

[0117] 27 spacers

[0118] 30 Control unit

[0119] 31 second circuit board, control board

[0120] 32 copper foil

[0121] 33 Contact element

[0122] 34 Contact screw

[0123] 35 Discharge connection

[0124] 36 power connectors

[0125] 37 Main switch

[0126] 38 User interface

[0127] 39 Charging interface

[0128] 40 second cell holder

[0129] 41 second magnet holder

[0130] 42 Insulation layer

[0131] 43 second connector

[0132] 50, 50' first layer arrangement

[0133] 60, 60' second layer arrangement 70 cover plate

[0134] 71 Fastening element, fastening screw

[0135] 72 fastening nut

[0136] 73 magnetic grid 74 contact magnet

[0137] 75 Distance magnet

[0138] 76 Insulator, holding frame

[0139] 77 Switch group RX first lateral direction

[0140] RY second lateral direction

Claims

Patent claims 1. Battery system with a plurality of battery cells (11) and a first circuit board (12), wherein a number of conductive and preferably ferromagnetic elements (14) are arranged on or in the first circuit board (12), and a magnet (15) is arranged between a number of battery cells (11) and a conductive and preferably ferromagnetic element (14) such that its magnetic force (15) holds the respective battery cell (11) to the first circuit board (12) at least in a direction towards the first circuit board (12), and that the magnet (15) creates an electrically conductive connection between a pole of the respective battery cells (11) and the first circuit board (12).

2. Battery system (10) according to claim 1, wherein for a plurality of the battery cells (11), preferably for each of the battery cells (11), a temperature element (17) is arranged on a circuit board (12, 31) and is connected to the battery cell (11) by means of the circuit board (12, 31) for temperature measurement (17).

3. Battery system (10) according to claim 2, wherein only one AD converter (21) is used for a plurality of the temperature elements (17), preferably all temperature elements (17), and wherein the AD converter (21) preferably converts temperature signals of the temperature elements (17) separately by means of multiplexing.

4. Battery system (10) according to one of the preceding claims, wherein a cell holder (25) holds a plurality of the battery cells (11) in a fixed position relative to one another in at least one lateral direction.

5. Battery system (10) according to one of the preceding claims, wherein the magnets (15') are arranged on the first circuit board (12') in a force-fitting and / or form-fitting manner by means of a fastening means (71), wherein the fastening means (71) is preferably arranged partly in a through-bore which extends through the magnet (15'), the conductive and preferably ferromagnetic element (14') and the first circuit board (12').

6. Battery system (10) according to one of the preceding claims, wherein on a side of the battery cells (11) opposite the first circuit board (12), a power contact to the respective battery cell (11) is produced by means of an electrically conductive film (32), which is preferably pressed onto a corresponding pole of the battery cell (11) by means of the magnetic force of a further magnet (15), wherein the electrically conductive film (32) is particularly preferably conductively connected to a second circuit board (31) by means of a contact element (33).

7. Battery system (10) according to one of the preceding claims, wherein on a side of the battery cells (11) opposite the first circuit board (12), a power contact from at least one battery cell (11) to the second circuit board is made by means of a magnetic grid (73) with square magnets (74, 75) arranged in the grid, in which magnets (74, 75) arranged edge-to-edge adjacently preferably have opposite magnetic polarities, and the magnets (74, 75) comprise contact magnets (74), which are each arranged adjacent to a battery cell (11), and optionally spacer magnets (75).

8. Battery system (10) according to one of the preceding claims, wherein a plurality of battery cells (11) are conductively connected to form a switching group by means of the conductive and preferably ferromagnetic elements (14), the electrically conductive foil (32) and / or the magnetic grid.

9. Battery system (10) according to claim 8, which comprises a plurality of switching groups of battery cells (11), and wherein at least one grid square of an insulator is arranged between two different switching groups of battery cells (11) on a side opposite the first circuit board (12).

10. Control unit (30) for a battery system (10) according to one of the preceding claims, which controls states of the individual battery cells (11) and switches the battery cells (11) accordingly and / or issues a warning signal.

11. Control unit (30) for a battery system (10) according to claim 10, wherein a degraded battery cell (11) can be identified by a user by means of the warning signal.

12. A control method for a battery system (10) according to one of claims 1 to 9, wherein for individual battery cells (11), it is checked whether their temperature lies within a defined range.

13. A control method for a battery system (10) according to claim 12, wherein, preferably using their temperature, a state of the respective battery cell (11) is determined and output for a number of battery cells (11) in a color-coded representation of the battery system (10).

14. A computer program product comprising a computer program that can be loaded directly into a control unit (30) of a battery system (10), with program sections for executing all steps of a method according to claim 12 or 13 when the computer program is executed in the control unit (30).Computer-readable medium on which program sections are stored that can be read and executed by a computer unit in order to carry out all steps of a method according to claim 12 or 13 when the program sections are executed by the computer unit.