Flex foil conductor track as compensating resistor

Abstract

A flexible foil conductor track (122) as a compensating resistor for charge or discharge compensation of a battery cell (102), wherein the flexible foil conductor track (122) is arranged between the battery cell (102, 104, 105, 106) and an integrated circuit (112) comprising a conductive material, characterized in that the flexible foil conductor track (122) has a defined conductor track routing (204) and / or the flexible foil conductor track (122) has a defined conductor track width and / or the flexible foil conductor track (122) has a specific conductor track thickness which is dimensioned such that the current required for charge and discharge compensation occurs directly at the flexible foil conductor track (122), and / or the flexible foil conductor track (122) has a conductor track length, wherein the conductor track length is adapted to a spatial arrangement between the battery cell (102, 104, 105, 106) and the integrated circuit.

Description

Technical area

[0001] According to the invention, a flexible foil conductor track is disclosed as a balancing resistor for charge and / or discharge equalization. The invention further relates to a battery management system with the flexible foil conductor track as a balancing resistor and a method for managing the charge and / or discharge equalization of battery cells with the battery management system. State of the art

[0002] Balancing resistors are used in battery storage systems to ensure that all battery cells in the battery system are charged and discharged evenly, especially in systems with multiple battery cells. The primary purpose of this is to minimize voltage differences between the individual cells to ensure the longest possible service life and efficient use of the available energy. Balancing resistors are typically used in the automotive sector as passive balancing resistors, where charged battery cells are discharged via balancing resistors, and the excess energy is converted into heat. These balancing resistors are usually located in a control unit (CSC) or, increasingly, on a flexible film between a cell and the control unit.

[0003] US 2020 059 10 6 A1 relates to a battery management system with configurable batteries. The battery management system generally includes one or more cell control units, each configured to control and / or balance the charge in a plurality of battery cells, and a main controller electrically connected to the cell control unit or units. The cell control unit or units as a whole include one or more switches configured to be electrically connected to a plurality of battery cells, and a resistor, capacitor, or inductor that is or can be electrically connected to a switch. The main controller is configured to open or close each switch.The configurable battery comprises a plurality of battery cells and switches configured to connect or disconnect battery cells in a configurable or predefined manner.

[0004] Typically, balancing resistors used in the state of the art tend to increase the balancing current and thus the power loss and heat generated. This leads to thermal overheating in the resistor itself and / or in the battery / control unit housing or flex foil. Typically, a large number of resistors are used to balance the battery's power. This often results in a power spread when multiple resistors are used and the resistors are spatially distributed. In some cases, a cooling connection is required, which is very expensive and mechanically complex. Disclosure of the invention

[0005] According to the invention, a flexible foil conductor track is disclosed as a compensating resistor for charge or discharge compensation of a battery cell, wherein the flexible foil conductor track is arranged between the battery cell and an integrated circuit with a conductive material.

[0006] The flexible foil conductor track has a defined conductor track routing and / or a defined conductor track width and / or a specific conductor track thickness, which is dimensioned such that the current required for charge and discharge compensation occurs directly at the flexible foil conductor track, and / or the flexible foil conductor track has a conductor track length, wherein the length is adapted to a spatial arrangement of the at least two energy storage devices.

[0007] For the purposes of the invention, a flexible foil conductor track is understood to be a conductor track or a path on a flexible printed circuit board made of a flexible material, at least one flexible foil. For example, the flexible foil conductor track can be arranged between a cell and a control unit, resulting in a specific power resistance that depends on the specific resistance of the conductor material, the cross-section, and the cable length. The flexible foil conductor track according to the invention exploits this effect. The resistance of the conductor track can be adjusted to the desired compensating resistance by means of a suitable, defined conductor track routing, a conductive material, a defined conductor track width that influences the cross-section of the flexible foil conductor track, and a specific conductor track thickness.

[0008] A balancing resistor, within the meaning of the invention, is a component for ensuring voltage equalization between the individual battery cells of a battery unit or battery pack. Balancing resistors are used, for example, in battery systems of electric vehicles or other applications where uneven charging or discharging voltages occur, particularly when the battery cells differ in their characteristics. The solution according to the invention counteracts this by directing the charging current from the more highly charged battery cells to the less highly charged battery cells, or by discharging the more highly charged battery cells to the level of the less highly charged battery cells.This advantageously optimizes both the service life and the performance of batteries, since all battery cells within the battery unit are evenly charged and discharged by the solution according to the invention.

[0009] A battery cell, battery and cell is any electrochemical device with at least one anode, one cathode and one electrolyte that is capable of absorbing, storing and, when needed, releasing electrical energy.

[0010] With the solution according to the invention, the resistance of the flexible foil conductor can be adjusted according to the desired compensating resistance, for example, by specifically varying the defined conductor track length and / or the specific conductor track thickness and / or the conductive material, as well as the defined conductor track routing. For example, by selecting conductive materials such as nickel, tin, brass, or an alloy of these materials, a higher specific resistance can be achieved than with the copper material typically used.

[0011] In the following, the terms “battery cell”, “battery” and “cell” are used synonymously.

[0012] In an advantageous development of the flexible foil conductor track proposed according to the invention, the conductive material is selected from a group comprising nickel, tin or brass.

[0013] By using conductive materials such as tin, nickel, or brass, a higher resistivity than copper can be achieved. Furthermore, the conductive materials according to the invention exhibit higher oxidation resistance and lower costs than the commonly used copper materials.

[0014] In an advantageous development of the flex foil conductor track proposed according to the invention, the conductive material comprises an alloy material, wherein the alloy material is selected from the group comprising nickel, tin or brass.

[0015] The alloy of nickel, tin or brass proposed according to the invention also advantageously makes it possible to achieve a material that is more resistant to the raw materials.

[0016] In a further advantageous development of the flexible foil conductor track proposed according to the invention, the energy storage device is a battery or a battery cell.

[0017] In a further advantageous development of the flexible foil conductor track proposed according to the invention, the conductor track thickness is constant along the entire conductor track length.

[0018] Furthermore, the constant conductor thickness proposed by the invention across the entire conductor length avoids hot spots, compared to a variable conductor thickness across the entire conductor length. According to the invention, constant conductor thicknesses enable a uniform distribution of the electrical current while simultaneously avoiding hot spots. This reduces the likelihood of local overloading of the compensating resistor. A further advantage is improved heat distribution and thus heat dissipation.

[0019] In a further advantageous development of the flexible foil conductor track proposed according to the invention, the conductor track guide has a straight conductor track guide or a meandering conductor track guide with repeating loops and / or bends, such that the meandering conductor track guide serves to increase an electrical resistance compared to the straight conductor track guide.

[0020] For example, in the case of a large number of battery cells arranged closely next to one another and acting as a battery cell unit, an increase in resistance can be achieved by a meandering conductor path or by a longer conductor path, which is achieved by the meandering conductor path, and / or by a thinner conductor path thickness, if a desired resistance value of the compensating resistor is not reached with a straight and thick conductor path.

[0021] In a further advantageous development of the flexible foil conductor track proposed according to the invention, a flexible foil conductor track has a variable resistance, wherein the electrical resistance can be adjusted by selecting a conductive material.

[0022] For example, a desired resistance of the flexible foil conductor track can be achieved by selecting a conductive material according to a specific requirement. This can be influenced, for example, by carefully selecting the conductive material through its conductivity properties. For example, a nickel-tin alloy can achieve lower conductivity than pure tin, with the resistance of the nickel-tin alloy increasing compared to pure tin.

[0023] Furthermore, the invention relates to a battery management system comprising: - a number of battery cells, the battery cells being connected in series, - an integrated circuit, the integrated circuit comprising at least: i. one or more connectors, wherein the one or more connectors comprise a physical connection between the individual battery cells and the integrated circuit, ii. one or more filter elements, wherein the one or more filter elements are designed to minimize noise in the measured voltage values, and iii. one or more control units with integrated circuit chips that can make a decision based on a measured voltage value difference, wherein each battery terminal of the battery cells is connected to the connector via a flexible foil conductor track, wherein the flexible foil conductor track is designed as a balancing resistor for balancing the charge or discharge of a battery cell, wherein the flexible foil conductor track is activated when a voltage difference is identified in the one or more control units between the battery cells that exceeds a predetermined threshold value.

[0024] Furthermore, the invention relates to a method for managing the charge and / or discharge balance of battery cells with the battery management system, comprising the following steps: a. Monitoring the voltage of individual battery cells via the integrated circuit, b. Decide on the activation of one or more flexible foil conductor tracks as a balancing resistor for the charge and / or discharge compensation of the battery cells by switching chips in the control unit, based on the measured voltage values ​​for the individual battery cells, c. Activating the charge and / or discharge equalization of the one or more battery cells when the measured voltage difference of the one or more battery cells exceeds a predefined threshold, d. Monitoring the charge and / or discharge balance for each battery cell and e. Deactivating charge and / or discharge equalization for each battery cell when the voltage difference is within a predefined threshold.

[0025] Furthermore, the invention relates to the use of the battery management system to enable adaptive control of the flex foil conductor track and uniform load distribution, thereby extending battery life. Advantages of the invention

[0026] The flexible foil conductor track according to the invention can be advantageously used as a compensating resistor due to the high degree of freedom in designing the conductor track, such as specific conductor track thickness, defined conductor track width, and defined conductor track length. The flexible foil conductor track according to the invention as a compensating resistor ensures a uniform charge distribution such that the one or more battery cells with an increased energy content in a battery system or in a battery unit composed of a plurality of battery cells are loaded. The optimization of the charge distribution achieved by the cell connector according to the invention makes it possible to improve the overall performance of the battery system. This is particularly true in applications where a reliable and constant energy supply is required, such as in electric vehicles.

[0027] The flexible foil conductor track used as a balancing resistor according to the invention achieves exceptionally good heat distribution within the battery across the entire length of the supply line. This ensures that excessive heat generation, so-called hotspots, due to balancing occurs neither locally (in the resistor) nor regionally (for example, in the control unit or at the location of a resistor).

[0028] Advantageously, the flexible foil conductor track according to the invention can be used as a trimming resistor, eliminating the need for separate resistors, thus saving component and assembly costs. Furthermore, a significant space saving effect can be achieved, for example, on a circuit board (integrated resistors), or assembly of the flexible foil can be avoided entirely.

[0029] In addition, a lower risk of failure is achieved through avoidable hotspots and by reducing the number of components, for example in a battery management system that includes a flex foil conductor track as a compensating resistor, which in turn leads to efficient cost savings through increased longevity and lower maintenance and repair costs.

[0030] The inventive solution of the flexible foil conductor track further ensures that any heat generated is advantageously distributed through the flexible foil conductor track, whereby the heat generated is used to preheat the battery. Short description of the drawings

[0031] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

[0032] They show: Fig. 1 a schematic representation of the battery management system, Fig. 2 a graphic representation of a section of the battery management system, Fig. 2.1 a graphic representation of a meandering flex foil conductor track, Fig. 2.2 a graphic representation of a straight flex foil conductor track and Fig. 3 a schematic representation of the method for managing the charge and / or discharge balance of battery cells. Embodiments of the invention

[0033] In the following description of the embodiments of the invention, identical or similar elements are designated by the same reference numerals, whereby a repeated description of these elements is omitted in individual cases. The figures only schematically illustrate the subject matter of the invention.

[0034] Fig. Figure 1 shows a schematic representation of a battery management system 100. The battery management system 100 comprises four battery cells 102, 104, 106, 108 connected by a connector 110. This connection has five flexible foil conductor tracks 122, with each battery cell 102, 104, 106, 108 being assigned a flexible foil conductor track 122 at each battery terminal. The connector 110 establishes a physical connection between the battery cells 102, 104, 106, 108 and the integrated circuit 112, wherein the integrated circuit 112 monitors the voltage of the individual battery cells 102, 104, 106, 108 and, if necessary, regulates it such that the voltages of the individual battery cells 102, 104, 106, 108 are within a predetermined threshold value. This is achieved, for example, by discharging and / or charging one or more battery cells 102, 104, 106, 108 that deviate from the threshold value. Fig. The integrated circuit 112 shown in Figure 1 comprises a filter element 114 and a control unit 116, wherein the control unit 116 checks the voltage differences of the respective battery cells 102, 104, 106, 108. The control unit 116 comprises a switching chip 118 with a switch 120. Each battery cell 102, 104, 106, 108 is assigned its own switching chip 118, which is not shown here. Furthermore, Fig. 1, a current flow 124 is shown in the form of arrows, wherein the current flow 124 occurs when a voltage deviation of one or more battery cells 102, 104, 106, 108 is identified by the control unit 116. If a voltage difference between the battery cells 102, 104, 106, 108 is detected, the control unit 116 carries out a charge and / or discharge equalization by the switch 120 located in the switching chip 118 switching the current flow 124 via the flexible foil conductor track 122, whereby a charge and / or discharge equalization occurs at one or more battery cells 102, 104, 106, 108.

[0035] Fig. 2 shows a graphic representation of a section 202 of the battery management system 100, wherein a battery cell 102 and the connection formed by two flexible foil conductor tracks 122 with the connector 110 are shown.

[0036] Fig. 2.1 and Fig. 2.2 each show two different flexible foil conductor tracks as examples. Fig. 2.1 is a meandering conductor path, namely an exemplary defined conductor path 204.1, with a first conductor path width, namely an exemplary defined conductor path width 206.1, a first conductor path length 210.1 and a first conductor path thickness 212.1. Fig. Figure 2.2 shows a straight conductor path, namely an exemplary defined conductor path 204.2, with a second conductor path width, namely an exemplary defined conductor path width 206.2, a second conductor path length 210.2, and a second conductor path thickness 212.2. For example, by repeatedly grinding and / or bending the meandering conductor path 204.1, the electrical resistance can be increased compared to the straight conductor path 204.2. Furthermore, the resistance of the flexible foil conductor path can be adjusted according to the desired resistance by alternative specific adaptations to the design of the flexible foil conductor path by varying the conductor path length, the conductor path thickness, the conductor path width, the conductor path, and the conductor path material.

[0037] As from Fig. 3, the illustrated embodiment of a method 300 according to the invention for managing the charge and / or discharge balance of battery cells 102, 104, 106, 108 comprises Fig.3, the illustrated embodiment of a method 300 according to the invention for controlling the charge and / or discharge equalization of battery cells 102, 104, 106, 108 comprises. In a first step, a voltage of the individual battery cells 102, 104, 106, 108 is monitored 302 via the integrated circuit 112. In a second step, a decision 304 is made about activating one or more flexible foil conductor tracks 122 as a compensation resistor for the charge and / or discharge equalization of the battery cells 102, 104, 106, 108 by switching chips 118 in the control unit 116 based on the measured voltage values ​​for the individual battery cells 102, 104, 106, 108. In the third step, the charge and / or discharge equalization of the individual Battery cell(s) 102, 104, 106, 108, if the measured voltage difference of the individual battery cell(s) 102, 104, 106, 108 exceeds a predetermined threshold value.In the fourth step, the charge and / or discharge balancing is monitored 308 for each battery cell 102, 104, 106, 108. Subsequently, the fourth step is performed, which includes monitoring 308 the charge and / or discharge balancing for each battery cell 102, 104, 106, 108. The final fifth step includes deactivating 310 the charge and / or discharge balancing for each battery cell 102, 104, 106, 108 if the voltage difference of the battery cell(s) is within predetermined threshold values.

[0038] For example, the activation 306 of the charge and / or discharge equalization of one or more battery cells 102, 104, 106, 108 can be carried out by a switching chip 118 located in the control unit 116. A switching chip 118 can, for example, have a switch 120, wherein, for example, when a battery voltage exceeds or falls below a threshold value, the switching chip 118 is controlled by activating the switch 120 such that the one or more battery cells 102, 104, 106, 108 are discharged and / or charged to the appropriate threshold range. In the event that all battery cells 102, 104, 106, 108 have a suitable voltage within the permissible threshold, all switches 120 of the switching chips 118 of the control unit 116 are in the open position, whereby no charge and / or discharge equalization takes place.

[0039] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of one skilled in the art. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2020 059 10 6 A1

[0003]

Claims

[1] Flexible foil conductor track (122) as a compensating resistor for charge or discharge compensation of a battery cell (102, 104, 106, 108), wherein the flexible foil conductor track (122) is arranged between the battery cell (102, 104, 106, 108) and an integrated circuit (112), comprising a conductive material, characterized by , that - the flexible foil conductor track (122) has a defined conductor track routing (204.1, 204.2) and / or - the flexible foil conductor track (122) has a defined conductor track width (206.1, 206.2) and / or - the flexible foil conductor track (122) has a specific conductor track thickness (212.1, 212.2) which is dimensioned such that a current required for charge and discharge compensation occurs directly at the flexible foil conductor track (122), and / or - the flexible foil conductor track (122) has a conductor track length (210.1, 210.2), wherein the conductor track length (210.1, 210.2) is adapted to a spatial arrangement between the battery cell (102, 104, 106, 108) and the integrated circuit (112). [2] The flex foil conductor track (122) of claim 1, wherein the conductive material is selected from a group comprising nickel, tin, or brass. [3] The flex foil conductor track (122) of claim 1, wherein the conductive material comprises an alloy material, wherein the alloy material is selected from the group comprising nickel, tin, or brass. [4] Flexible foil conductor track (122) according to one of the preceding claims, wherein the conductor track thickness (212) is constant along the entire conductor track length (210). [5] Flexible foil conductor track (122) according to one of the preceding claims, wherein the conductor track guide (204) has a straight conductor track guide (204.2) or a meandering conductor track guide (204.1) with repeating loops and / or bends, characterized by that the meandering conductor track (204.1) serves to increase an electrical resistance compared to the straight conductor track (204.2). [6] Flexible foil conductor track (122) according to one of the preceding claims, wherein a flexible foil conductor track (122) has a variable resistance, wherein the electrical resistance is adjustable by a selection of a conductive material. [7] Battery management system (100), comprising: - a number of battery cells (102, 104, 106, 108), wherein the battery cells (102, 104, 106, 108) are connected in series, - an integrated circuit (112), wherein the integrated circuit (112) comprises at least: i. one or more connectors (110), wherein the one or more connectors (110) comprise a physical connection between the individual battery cells (102, 104, 106, 108) and the integrated circuit (112), ii. one or more filter elements (114), wherein the one or more filter elements (114) are configured to minimize noise in the measured voltage values, and iii. one or more control devices (116) with integrated circuit chips (118) which make a decision on the basis of a measured voltage value difference, - wherein each battery terminal of the battery cells (102, 104, 106, 108) is connected to the plug connector (110) via a flexible foil conductor track (122), wherein the flexible foil conductor track (122) is designed as a compensating resistor for charging or discharging a battery cell (102, 104, 106, 108), wherein the flexible foil conductor track (122) is activated when a voltage difference is identified in the one or more control devices (116) between the battery cells (102, 104, 106, 108) that exceeds a predetermined threshold value. [8] Method (300) for managing the charge and / or discharge balance of battery cells (102, 104, 106, 108) with the battery management system (100) according to claim 7, comprising the following steps: a. monitoring (302) a voltage of the individual battery cells (102, 104, 106, 108) via the integrated circuit (112), b. deciding (304) on the activation of the one or more flexible foil conductor tracks (122) as a compensating resistor for the charge and / or discharge compensation of the battery cells (102, 104, 106, 108) by switching chips (118) in the control unit (116), based on the measured voltage values ​​for the individual battery cells (102, 104, 106, 108), c. activating (306) the charge and / or discharge compensation of the one or more battery cells (102, 104, 106, 108) when the measured voltage difference of the one or more battery cells (102, 104, 106, 108) exceeds a predefined threshold value and d. monitoring (308) the charge and / or discharge balance for each battery cell (102, 104, 106, 108) and e. Deactivating (310) the charge and / or discharge compensation for each battery cell (102, 104, 106, 108) if the voltage difference is within a predetermined threshold. [9] Use of the battery management system (100) according to claim 7 to enable adaptive control of the flex foil conductor track (122) and uniform load distribution, thereby extending battery life.

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