CONTACTING BOARD

Description

[0001] The invention relates to a contact board for an energy storage module, in particular for a lithium-ion battery, comprising a flexible plastic substrate that provides first conductive tracks for an electrical connection between a sensor board and the terminals of the energy storage module, wherein the plastic substrate has a first large side and a second large side aligned parallel to it, one of the two large sides being equipped with a heating element. The invention further relates to an energy storage module, in particular a lithium-ion battery, comprising a plurality of electrically interconnected lithium-ion cells, wherein the energy storage module is equipped with a contact board.

[0002] A cell connector unit and / or cell voltage tap unit is known from the prior art according to DE 10 2015 010 925 A1. This unit has a base body, which can also be called a circuit board and can be made of plastic. This base body is equipped with a temperature control unit, which can be electrically designed, specifically in the form of a heating element. A meandering resistance wire can be used as the heating element.

[0003] Furthermore, a battery module with multiple battery cells is known from the prior art according to US 2020 / 036064 A1, wherein the cell terminals of the battery cells are connected to each other via busbars. These busbars are covered by heating elements, each heating element having a thermally conductive pad. Each pad is in contact with a heat distribution plate, heating elements being attached to the heat distribution plates.

[0004] A contacting board of the aforementioned, i.e. generic type, is known from EP 3 715 171 B1.

[0005] The contact board known from EP 3 715 171 B1 has a flexible plastic substrate. This is designed, for example, in the form of a film.

[0006] The plastic substrate has initial conductive traces which, in the final assembly state, serve to connect a sensor board to the terminals of the energy storage module. For this purpose, the contact board has contact elements that are electrically connected to the terminals of the energy storage module in the final assembly state.

[0007] The first conductive traces on the plastic substrate are electrically connected at one end to the contact elements that interact with the terminals of the energy storage module and at the other end to a sensor board, thus forming an electrically conductive connection between the sensor board and the terminals of the energy storage module. The sensor board can be a separate board or an integral component of the contact board.

[0008] The sensor board has an electronic circuit designed to evaluate voltage measurements.

[0009] The energy storage module comprises multiple electrically interconnected cells. Each cell has two terminals: a negative terminal and a positive terminal. For voltage measurement, the individual cells of the energy storage module are electrically connected to the sensor board, a purpose for which the contact board serves as previously described.

[0010] Voltage values ​​recorded by the sensor board can be evaluated using the electronic circuitry provided by the sensor board. It is also possible to compare the voltage values ​​of individual cells within the energy storage module. This allows, in particular, the determination of the state of charge, not only of the energy storage module as a whole, but also of individual cells.

[0011] In its final assembly state, the contact board is placed on top of the energy storage module, aligning it vertically. The contact board is secured in position by connecting its contact elements to the corresponding terminals of the energy storage module, for example, by soldering or welding. Furthermore, the contact board can also be glued or otherwise bonded to the top of the energy storage module or to the top of its individual cells.

[0012] Although the contact board known from EP 3 715 171 B1 has proven itself in everyday practical use, there is room for improvement, particularly with regard to a broader range of applications. It is therefore the Taskthe invention to constructively further develop a contacting board of the type mentioned above in such a way that an expanded range of applications is achieved while simultaneously increasing performance.

[0013] To Solution The invention proposes a contact board of the generic type to address this problem, characterized in that the plastic substrate is equipped on its side facing away from the energy storage module in the final assembled state with a third conductor track providing a balancing resistor.

[0014] The plastic substrate, which is, for example, a flexible plastic film, has two large sides that are aligned parallel to each other. In the final assembly state, one of these two sides faces the energy storage module. The other side of the plastic substrate, opposite this side, faces away from the storage module in the final assembly state.

[0015] The plastic substrate is designed to have a heating element, with one of its two large sides being equipped with such an element. Preferably, the side of the plastic substrate facing the energy storage module in its fully assembled state should have the heating element.

[0016] The contact board provides two functionalities. Firstly, it features conventional conductive traces that, in accordance with the prior art, serve to electrically connect a sensor board to the terminals of the energy storage module. Secondly, the contact board is equipped with a heating element that allows the energy storage module or its cells to be heated as needed. To ensure the most direct heat transfer possible from the heating element to the energy storage module or its cells, the heating element is preferably located on the side of the plastic substrate that faces the energy storage module in the final assembly. Alternatively, the heating element can also be located on the side of the plastic substrate that faces away from the energy storage module in the final assembly.In this case, the plastic substrate of the contact board does have a disadvantageous thermal insulating effect; however, due to the very thin design of the plastic substrate, for example, as a flexible plastic film, only a slight deterioration in heat transfer occurs under normal operating conditions. An advantage of arranging the heating element on the large side of the plastic substrate facing away from the energy storage module in the final assembly state is that, during assembly and / or maintenance, the correct and intended alignment of the heating element in relation to the individual cells provided by the energy storage module can be directly verified by visual inspection, i.e., without any additional tools.

[0017] Due to technological limitations, not all energy storage modules, especially lithium-ion batteries, can be charged at low temperatures. The contact board addresses this issue by enabling demand-based and selective operation of the heating element provided by the contact board, allowing for a predefined temperature for the individual cells of the energy storage module, thus optimizing cell charging. This eliminates the need for separate heating foils, as is known from prior art. The contact board, which is already part of the system, effectively replaces the heating foils by providing the additional functionality of the heating element.The contact board thus has an expanded range of applications, as it not only serves to electrically connect a sensor board to the terminals of the energy storage module, but also offers the possibility of heating the energy storage module or the cells it provides if necessary.

[0018] Integrating a heating element into a circuit board is particularly cost-effective, as it eliminates the need for a separate heating element, such as a heating film, and also avoids the need for other additional components. Therefore, the final design of an energy storage module using a circuit board proves to be simpler and thus more cost-effective in both manufacturing and assembly compared to the state of the art.

[0019] The arrangement of the heating element on the contact board also offers the advantage that the heating element can be easily connected electrically to the energy storage module, so that in normal operation the heating element is powered by the total voltage of the energy storage module. Alternatively, an external power supply for the heating element can of course be provided. However, the electrical connection of the heating element to the energy storage module is advantageous because it requires no additional components and / or assembly steps during manufacturing.

[0020] Overall, the contact board provides a multifunctional circuit board, ensuring, on the one hand, a proper electrical connection between a sensor board and the connection terminals of the energy storage device in its intended use, and on the other hand, a heating device that, if necessary, allows the energy storage module to be heated to a temperature that supports or ensures an optimized charging process.

[0021] According to the invention, the plastic substrate is equipped on one of its two large sides with a third conductor track providing a balancing resistor. In this embodiment, the contact board has a third conductor track. This provides at least one balancing resistor. Preferably, several such balancing resistors are provided, one resistor per parallel connection. The conductor track is formed on one of the two large sides of the plastic substrate. In this context, it is preferred that the large side of the plastic substrate with the third conductor track faces away from the energy storage module in the final assembly state. Thus, the heating element is provided by a first large side of the plastic substrate, whereas the third conductor track is formed on the other of the two large sides of the plastic substrate.Alternatively, both the third conductor track and the heating element can be provided by one and the same large side of the plastic substrate. However, particularly for reasons of space, it is preferable to use both large sides of the plastic substrate equally for accommodating the individual conductor tracks. Therefore, and also for reasons of simplified manufacturing, it is desirable to place the heating element on one of the two large sides of the plastic substrate and both the first and third conductor tracks on the other.

[0022] Passive balancing ensures that all cells in the energy storage module are charged equally during charging. Passive balancing operates only near the end of the charging process, i.e., when the cells are almost fully charged. For each cell that has already reached the final charging voltage, a balancing resistor is connected in parallel, limiting the voltage to this voltage. Subsequently, this cell is only charged slightly further or even discharged slightly, while the other cells, which have not yet reached the final charging voltage, continue to receive the full charging current. The power rating of the parallel resistor is matched to the charging current, as excess energy is dissipated as heat in the resistor. The main advantages of this balancing method are its cost-effectiveness and ease of implementation.

[0023] According to the current state of the art, balancing resistors for passive balancing are housed on a dedicated circuit board within a battery management system. A disadvantage of this known arrangement is that thermal management limits balancing currents to low levels. Furthermore, differing voltage levels of the cell chemistries NMC (lithium nickel manganese cobalt), LFP (lithium iron phosphate), and LTO (lithium titanium oxide) pose a significant drawback when selecting resistors for a modular battery management system.

[0024] The now-provided placement of the balancing resistors on a flexible contact board, rather than on a battery management system board, overcomes these disadvantages. The high heat capacity of the energy storage module cells ensures good heat dissipation, which allows for significantly higher balancing currents. Furthermore, the arrangement of the balancing resistors on the flexible contact board enables the resistor values ​​to be tailored to the voltage levels of the cells. This results in a significant performance increase for passive balancing.

[0025] According to a further feature of the invention, the third conductor track is electrically connected to the first conductor tracks. This provides a direct electrical coupling between the first conductor tracks and the third conductor track, which provides a balancing resistor. As a result, the contact board has a simple design, which also makes it possible to easily apply all conductor tracks by printing them onto the flexible plastic substrate of the contact board.

[0026] As already explained above, according to a further feature of the invention, it is preferred that the side of the plastic substrate facing away from the energy storage module in the final assembly state is equipped with the third conductor track and / or the first conductor tracks. Accordingly, the heating device or the second conductor track provided by the heating device is arranged on the side of the plastic substrate facing the energy storage module in the final assembly state.

[0027] According to a further feature of the invention, the heating device comprises a second conductor track made of copper, preferably printed on the plastic substrate.

[0028] The heating element is designed as a quasi-heating coil formed by a conductive track applied to the plastic substrate. The conductive track is preferably made of copper and is, for example, printed onto the plastic substrate. The result is a contact board with a plastic substrate as a carrier material, equipped with conductive tracks on one side and with conductive tracks on the other. The conductive tracks serve, as previously described, for the electrical connection of a sensor board to the terminals of the energy storage module, while the conductive tracks form the heating element according to the invention. The design of the heating element proves to be particularly simple and cost-effective.In particular, this embodiment makes it possible to form a contact board in one step, which also provides the functionality of the heating device.

[0029] According to a further feature of the invention, the second conductor track is designed to have a meandering shape, at least in sections. This results in compact heating resistors which, thanks to their arrangement on the plastic substrate of the contact board, are positioned securely directly above a corresponding cell of the energy storage module in the final assembly state. This creates an overall compact heating device which, moreover, advantageously enables precise positioning of the individual cells of the energy storage module.

[0030] In this context, according to a further feature of the invention, it is proposed that the plastic substrate has a geometric configuration that corresponds to the cell arrangement within the energy storage module. For example, a ladder-shaped configuration of the plastic substrate can be provided, wherein the plastic substrate has strip sections that, in the final assembly state, lie directly above a cell of the energy storage module. These strip sections have, on their underside facing the respective cell, the meandering second conductor tracks of the heating device according to the invention. This ensures a direct and precise positioning between the second conductor tracks of the heating device and the respective cell of the energy storage module.

[0031] According to a further feature of the invention, the second conductor track is designed to be electrically connectable to the energy storage module. This advantageously allows the heating element to be powered from the total voltage of the energy storage module. Constructively, this can be implemented, for example, by having the second conductor track terminate in contacts which, in turn, are electrically connected to terminals of the energy storage module in the intended use.

[0032] According to a further feature of the invention, the contact board is provided with temperature sensors. These are coupled to the sensor board by means of corresponding conductor tracks, so that the electronic circuitry of the sensor board can be used to evaluate the cell temperature measurements provided by the temperature sensors under normal operating conditions. An evaluation of the recorded cell temperatures can serve not only to monitor the cell temperature but also to control the heating device. In particular, the recorded temperature values ​​can be used to determine at the beginning of a charging process whether the heating device should be switched on for optimized charging. Furthermore, automated deactivation of the heating device is also possible when the cell temperature required for optimized charging is reached.

[0033] According to a further feature of the invention, contact elements are provided that interact with the terminals of the energy storage device and are spaced apart from the plastic substrate. The contact elements are therefore not provided by the flexible plastic substrate of the contact board. In contrast to the prior art, this results in a much less delicate structure of the contact board, which is particularly advantageous with regard to the assembly of the contact board, especially because automated arrangement of the contact board on an energy storage module is much easier to implement.

[0034] The contact elements – also called cell taps – are preferably formed in a single manufacturing step along with the associated conductor tracks. Of course, a separate design of the contact elements from the conductor tracks is also conceivable. The crucial point, however, is that the contact elements are not supported by the plastic substrate of the contact board. Rather, the contact elements are positioned at a distance from the plastic substrate, meaning they are adjacent to it in the final assembled state. Connecting sections are used for the electrical contact between the contact elements and the corresponding conductor tracks of the plastic substrate, as will be explained in more detail below.

[0035] According to the prior art as described in EP 3 715 171 B1 cited above, the flexible plastic substrate of the contact board provides a main branch on the one hand and strip-shaped secondary branches on the other. The strip-shaped secondary branches, with their end regions opposite the main branch, each provide contact areas that each carry the contact elements interacting with the terminals of the energy storage device. In contrast to this design, the embodiment according to the invention omits strip-shaped secondary branches. Instead, the contact elements are spaced apart from the plastic substrate, i.e., formed outside of it, and are electrically connected directly to the first conductor track of the contact board via a corresponding electrical connection.The ladder-shaped design of the plastic substrate, which is preferred due to the heating device provided according to the invention, can therefore advantageously remain unchanged.

[0036] According to a further feature of the invention, a first conductor track terminates in a connection path to which a contact element is electrically connected. The connection path thus serves as an electrical bridge between the first conductor track and the contact element. Preferably, more than one contact element can be connected to a single connection path. The connection path therefore offers the advantage of being able to easily connect one or more contact elements electrically to a first conductor track. The use of two contact elements connected in parallel offers the particular advantage of increased reliability for cell voltage measurement. Furthermore, the design of the connection path eliminates the need for a welded connection, which simplifies manufacturing.In the case of assembly, it is then only necessary to electrically connect the contact elements to the cell poles, which is preferably done by welding.

[0037] According to a further feature of the invention, a preferably S-shaped connecting section is provided for the electrical connection of a contacting element to a connection path. A contacting element is thus electrically connected to a connection path via a connecting section. This connecting section advantageously allows the interacting contacting element to be positioned relative to the plastic substrate. This facilitates precise alignment of the contacting elements for electrical connection to a corresponding terminal of the energy storage module. To increase positional flexibility, the connecting section is preferably S-shaped. This allows for both elongation and angulation relative to the plastic substrate.Any inaccuracies in the fit between the position of the contact board on the electrical storage module and the position of the terminals of the energy storage module can thus be advantageously compensated for. This also makes it possible to compensate for any manufacturing tolerances.

[0038] According to a further feature of the invention, the connecting section and the associated contacting element are preferably formed in one piece from nickel and soldered to the connection path. In this embodiment, the contacting element is formed by a so-called nickel pad, which can be soldered directly to the associated connection path of the contact board via the integrally formed connecting section. This further facilitates simple and cost-effective manufacturing.

[0039] Further features and advantages of the invention will become apparent from the following description with reference to the figures. These show Figure 1 shows a schematic top view of the side of a contact board according to the invention facing an energy storage module in the final assembly state; Figure 2 shows a schematic detail view of a heating device provided by the side of the contact board facing the energy storage module; and Figure 3 shows a schematic detail view of the side of the contact board facing away from the energy storage module in the final assembly state, which is equipped with first and third conductor tracks.

[0040] A contact board 1 according to the invention is shown schematically in Figure 1 depicted.

[0041] The contact board 1 has a flexible plastic substrate 2, which is, for example, designed as a flexible plastic film. In the illustrated embodiment, the plastic substrate 2 is conductor-like and has longitudinal sections 15 on one side and transverse sections 16 on the other.

[0042] Fig. 1 The side 4 of the contact board 1 facing an energy storage module in its fully assembled state is visible. According to the invention, this side 4 of the plastic board 1, facing the energy storage module in its fully assembled state, is equipped with a heating element 5. The heating element 5 has a conductive track 6 applied, preferably printed, to the plastic substrate. This connection is particularly evident from the detailed view shown in [reference to detailed view]. Figure 2 .

[0043] The conductor track 6 of the heating device 5 is designed to have a meandering shape, at least in sections, as can also be seen in particular from the illustration according to Fig. 2 results.

[0044] The meandering course of the conductor tracks 6 creates quasi heating resistances which, when current is applied, heat the interacting cells of the energy storage module.

[0045] As can be seen from the presentation according to Fig. 1 As a result, the conductor track 6 in the area of ​​the transverse sections 16 of the plastic substrate 2 is designed to run in a meandering shape. In the fully assembled state of the contact board 1, these transverse sections 16 are located directly above the respective cells of the energy storage module. This ensures direct heat transfer from the heating element 15 to the corresponding cells of the energy storage module.

[0046] As can be seen from a synthesis of the Figure 1 and 2Furthermore, the contact board 1 also has temperature sensors 13. In the fully assembled state of the contact board, these sensors interact with the corresponding cells of the energy storage module and enable cell temperature measurement. The heating device 5 is preferably switched on or off by means of an electronic circuit depending on the cell temperatures detected by the temperature sensors 13.

[0047] The heating element 5 is preferably supplied from the total voltage of the energy storage module, for which purpose the conductor track 6 of the heating element 5 terminates in corresponding contacts. In the intended use, an electrical connection between the heating element 5 and the energy storage module is established via these contacts.

[0048] The flexible plastic substrate 2 also provides initial conductor tracks 3 for an electrical connection between a sensor board and the terminals of the energy storage module. These initial conductor tracks 3 are formed on the side 8 of the plastic substrate 2 facing away from the energy storage module in the final assembly state, as shown in the detailed illustration according to [reference to figure]. Fig. 3 This can be seen. For electrical contacting of the first conductor tracks 3 with one or more sensor boards not specifically shown in the figures, corresponding contacts 7 are provided, as can be seen in particular from the illustration according to Fig. 1 results.

[0049] On the terminal side, the contact board 1 provides contact elements 10. These are electrically connected to a first conductor track 3. For this purpose, a connection path 11 is provided by the plastic substrate 2, into which the first conductor track 3 electrically connects. An S-shaped connecting section 12 is provided for the electrical connection of a contact element 10 to the connecting path 11. The contact element 10 and the associated connecting section 11 are preferably formed in one piece. Nickel is the preferred material for the contact element 10 and the connecting section 12. Soldering is preferably used to connect a connecting section 12 to a connecting path 11.

[0050] The preferably S-shaped design of the connecting section 12 offers the advantage that the contacting element 10, which is not supported by the plastic substrate 2, can be adjusted in its position relative to the plastic substrate 2. This allows any manufacturing or positioning tolerances to be compensated for, ensuring proper contact between the contacting element 10 and a terminal of the energy storage module in every case. Furthermore, the S-shaped design of the connecting section 12 serves to compensate for relative movements between the contacting board 1 and the energy storage module under dynamic load.

[0051] As can be seen from the presentation according to Fig. 3Furthermore, it is shown that the plastic substrate 2 is equipped on its side 8 facing away from the energy storage module in the fully assembled state with a third conductor track 9, which provides a balancing resistor 14. The third conductor track 9 is electrically connected to the first conductor track 3 and thus also to the contact elements 10.

[0052] The contact board according to the invention provides a multifunctional contact board 1. This is because the contact board 1 according to the invention not only houses first conductor tracks for the electrical connection of a sensor board to the terminals of the energy storage module, but also integrates balancing resistors 14 and a heating element 5. The heating element 15 is located on one side of the plastic substrate 2, namely on side 4 facing the energy storage module in the final assembly state. The other conductor tracks, i.e., the first conductor tracks 3 and the third conductor tracks 9, are arranged on the other side of the plastic substrate 2, namely on side 8 facing away from the energy storage module in the final assembly state. Reference sign

[0053] 1 Contact board 2 Plastic substrate 3 First conductor track 4 Energy storage module facing side 5 Heating element 6 Second conductor track 7 Contacts 8 Energy storage module facing away side 9 Third conductor track 10 Contact elements 11 Connection path 12 Connection section 13 Temperature sensors 14 Balancing resistors 15 Longitudinal section 16 Transverse section 17 First large side 18 Second large side

Claims

1. Contacting board for an energy storage module, in particular a lithium-ion accumulator, comprising a flexible plastic substrate (2) that provides first conductor tracks (3) for an electrical connection of a sensor board to connection poles of the energy storage module, wherein the plastic substrate (2) has a first large side (17) and, aligned parallel thereto, a second large side (18), wherein one of the two large sides (17, 18) is equipped with a heating device (5), characterized in that the plastic substrate (2) is equipped, on its side (8) facing away from the energy storage module in the final assembled state, with a third conductor track (9) that provides a balancing resistor (14).

2. Contacting board according to claim 1, characterized in that the heating device (5) comprises a second conductor track (6) from copper applied to the plastic substrate (2), preferably printed thereon.

3. Contacting board according to claim 2, characterized in that the second conductor track (6) is designed to run in a meandering pattern, at least in sections.

4. Contacting board according to claim 2 or 3, characterized in that the second conductor track (6) is designed to be electrically connectible to the energy storage module.

5. Contacting board according to any one of the preceding claims, characterized in that the third conductor track (9) is electrically connected to the first conductor track (3).

6. Contacting board according to any one of the preceding claims, characterised in that the first (17) of the two large sides (17, 18) is equipped with the heating device (5) and the second (18) of the two large sides (17, 18) is equipped with the third conductor track (9) and, preferably, also with the first conductor tracks (3).

7. Contacting board according to any one of the preceding claims, characterized in that the large side (17) aligned with the heating device (5) is the side (4) of the plastic substrate (2) facing the energy storage module in the final assembled state.

8. Contacting board according to any one of the preceding claims, characterized in that the large side (18) equipped with the third conductor track (9) and / or the first conductor tracks (3) is the side (8) of the plastic substrate (2) facing away from the energy storage module in the final assembled state.

9. Contacting board according to any one of the preceding claims, characterized by contacting elements (10) cooperating with the connection poles of the energy storage module, which contacting elements are designed to be spaced apart from the plastic substrate (2).

10. Contacting board according to claim 9, characterized in that a first conductor track (3) leads into a connection path (11) to which a contacting element (10) is electrically connected.

11. Contacting board according to claim 9 or 10, characterized by a preferably s-shaped connecting section (12) under the interposition of which a contacting element (10) is electrically connected to a connection path (11).

12. Contacting board according to claim 11, characterized in that the connecting section (12) and the contacting element (10) are integrally formed preferably from nickel and are soldered to the connection path (11).

13. Energy storage module, in particular lithium-ion accumulator, comprising a plurality of electrically interconnected lithium-ion cells, characterized by a contacting board according to any one of the preceding claims 1 to 12.

14. Energy storage module according to claim 13, characterized in that the contacting board is electrically connected to pole connections provided by the energy storage module, wherein the large side (17) of the plastic substrate (2) facing the energy storage module has the heating device (5).