Flexible film lead as balancing resistor

Abstract

A flexible film conductor (122) as a balancing resistor for charge or discharge balancing of the cells (102), the flexible film conductor (122) being arranged between the cells (102, 104, 105, 106) and the integrated switching circuit (112), comprising an electrically conductive material, characterized in that the flexible film conductor (122) has a predetermined conductor guide (204) and / or the flexible film conductor (122) has a predetermined conductor width, and the flexible film conductor (122) has a predetermined conductor guide (204) and / or a predetermined conductor width, and the flexible film conductor (122) is arranged between the cells (102, 104, 105, 106) and the integrated switching circuit (112). The flexible film conductor (122) has a specific conductor thickness, which is measured in such a way that the current required for the balance of charge and discharge is generated directly at the flexible film conductor (122), and / or the flexible film conductor (122) has a conductor length, which is adapted to the spatial arrangement between the cells (102, 104, 105, 106) and the integrated switching circuit (102, 104, 105, 106), and / or the flexible film conductor (122) has a specific conductor thickness, which is measured in such a way that the current required for the balance of charge and discharge is generated directly at the flexible film conductor (122) and / or the flexible film conductor (122) has a conductor length.

Description

Technical Field

[0001] The present invention discloses a flexible thin-film conductor as a balancing resistor for charge and / or discharge balancing. The invention also relates to a battery management system having the flexible thin-film conductor as a balancing resistor and a method for managing charge and / or discharge balancing of battery cells using the battery management system. Background Art

[0002] Balancing resistors are used in battery storage systems to ensure that all cells in the battery system are charged and discharged evenly, particularly in systems with multiple cells. This requires minimizing 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 cells are discharged through the balancing resistors and excess energy is converted into heat. These balancing resistors are usually located in the control unit (CSC) or, increasingly, on a flexible film between the cells and the controller.

[0003] US2020059106 A1 relates to a battery management system with a configurable battery. The battery management system generally includes one or more single-cell control units and a main control unit, wherein each single-cell control unit is configured so that it controls and / or balances the charge in multiple battery cells, and the main control unit is electrically connected to one or more single-cell control units. A single-cell control unit or multiple single-cell control units as a whole include one or more switches and a resistor, capacitor or induction coil electrically connected or capable of being electrically connected to the switch, and the switch is configured so that it is electrically connected to multiple battery cells. The main control unit is configured to open or close each switch. The configurable battery includes multiple battery cells and a switch designed to connect or disconnect the battery cells in a configurable or predetermined manner.

[0004] Typically, balancing resistors used in accordance with the prior art tend to increase the balancing current and, therefore, the resulting power loss and heat. This results in overheating of the power loss / heat in the resistors themselves and / or in the battery / controller housing or the flexible film. Multiple resistors are typically used to balance the power of the batteries. Therefore, if multiple resistors are used and spatially distributed, this often results in power dispersion. In some cases, this requires very expensive and mechanically complex cooling connections. Summary of the Invention

[0005] According to the present invention, a flexible film conductor is disclosed as a balancing resistor for balancing the charge or discharge of a battery cell. The flexible film conductor is arranged between the battery cell and an integrated switching circuit and comprises a conductive material.

[0006] The flexible film conductor has a predetermined conductor guide and / or a predetermined conductor width and / or a specific conductor thickness, which is designed such that the current required for charge and discharge balancing is generated directly at the flexible film conductor, and / or the flexible film conductor has a conductor length, wherein the length is adapted to the spatial arrangement of the at least two energy stores.

[0007] For the purposes of the present invention, a "flexible film conductor" is understood to mean a conductor or path on a flexible printed circuit board made of a flexible material, i.e., at least one flexible film. The flexible film conductor can be arranged, for example, between a cell and a controller, where it generates a specific power resistance that depends on the resistivity of the conductor material, its cross-section, and the line length. The flexible film conductor according to the present invention exploits this effect. The resistance of the conductor can be set to the desired equilibrium resistance by suitably predefined conductor guides, conductive materials, a predefined conductor width that influences the cross-section of the flexible film conductor, and a specific conductor thickness.

[0008] A balancing resistor, within the meaning of the present invention, is a component used to ensure voltage balance between the cells of individual battery cells or battery packs. Balancing resistors are used, for example, in battery systems for electric vehicles or other applications where uneven charging or discharging voltages can occur, particularly if the cells have different properties. The solution according to the present invention counteracts this by directing the charging current from more highly charged cells to less highly charged cells or discharging more highly charged cells to the level of less highly charged cells. Because all cells within a battery cell are charged and discharged uniformly by the solution according to the present invention, this advantageously optimizes both the battery life and the available power.

[0009] Battery cells, batteries, and cells are any electrochemical device comprising at least one anode, a cathode, and an electrolyte, which can be used to receive, store, and, when required, release electrical energy.

[0010] In the solution according to the invention, the resistance of a flexible foil conductor, for example, can be adjusted by selectively varying a predetermined conductor length and / or a specific conductor thickness and / or a conductive material, as well as predetermined conductor routing, depending on the desired equilibrium resistance. By selecting a conductive material such as nickel, tin, brass, or alloys thereof, for example, a higher resistivity can be achieved than with copper, which is typically used, as opposed to these materials.

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

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

[0013] By using a conductor material such as tin, nickel or brass according to the invention, a higher resistivity can be achieved than with copper. Furthermore, the conductive material according to the invention has a higher oxidation stability and is less expensive than the commonly used copper material.

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

[0015] Furthermore, the alloy proposed according to the invention of nickel, tin or brass advantageously enables the realization of a material with a higher resistance than the starting material.

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

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

[0018] Furthermore, compared to a variable conductor thickness over the entire conductor length, the present invention's constant conductor thickness over the entire conductor length avoids hot spots. According to the present invention, the constant conductor thickness enables uniform current distribution while simultaneously avoiding hot spots. This reduces the probability of local overloading of the balancing resistor. A further advantage is improved heat distribution and, therefore, heat dissipation.

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

[0020] In the case of multiple battery cells that are arranged sealed to one another and function as a cell unit, if the desired resistance value of the balancing resistor would be lower in the case of straight and thicker wire guides, an increase in resistance can be achieved, for example, by a meandering wire guide or by a longer wire guide achieved with the aid of a meandering wire guide and / or by a thinner wire thickness.

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

[0022] Depending on specific requirements, the desired resistance of the flexible foil conductor can be achieved by selecting the conductive material, for example. The conductive properties of the material can be influenced, for example, by targeted selection of the conductive material. For example, a lower electrical conductivity can be achieved with an alloy of nickel and tin than with pure tin, with the resistance of the nickel-tin alloy increasing compared to pure tin.

[0023] Furthermore, the present invention relates to a battery management system comprising:

[0024] - a plurality of battery cells, wherein the battery cells are connected in series,

[0025] - the integrated switching circuit, wherein the integrated switching circuit comprises at least:

[0026] i. One or more plug connectors, wherein the one or more plug connectors comprise a physical connection between the individual cells and the integrated switching circuit,

[0027] ii. one or more filters, wherein the one or more filters are configured so as to minimize noise in the measured voltage value, and

[0028] iii. One or more controllers with integrated switch chips that can make decisions based on the measured voltage value differences,

[0029] In this case, each battery terminal of a cell is connected to a plug connector via a flexible film conductor, wherein the flexible film conductor is designed as a balancing resistor for charging or discharging balancing of the cell, wherein the flexible film conductor is activated if a voltage difference between the cells that exceeds a predetermined threshold value is detected in one or more controllers.

[0030] Furthermore, the present invention relates to a method for managing charge and / or discharge balance of battery cells using a battery management system, the method comprising the following steps:

[0031] a. Monitor the voltage of each cell through the integrated switching circuit,

[0032] b. Based on the measured voltage values ​​for each battery cell, a switch chip in the controller is used to determine whether to activate one or more flexible thin film conductors, which serve as balancing resistors for charging and / or discharging balance of the battery cells.

[0033] c. activating charge and / or discharge balancing of one or more cells if the measured voltage difference of one or more cells exceeds a predetermined threshold value,

[0034] d. Monitor charge and / or discharge balance for each cell, and

[0035] e. If the voltage difference is within a predefined threshold value, the charge and / or discharge balancing is deactivated for each cell.

[0036] Furthermore, the present invention relates to the use of a battery management system in order to enable adaptive control of the flexible thin-film conductors and uniform load distribution, thereby extending the battery life.

[0037] Advantages of the present invention.

[0038] Due to the wide range of freedom in conductor design, such as a specific conductor thickness, predetermined conductor width, and predetermined conductor length, the flexible film conductor according to the present invention can be advantageously used as a balancing resistor. The flexible film conductor according to the present invention, acting as a balancing resistor, ensures uniform charge distribution, allowing one or more cells in a battery system or battery cell composed of multiple cells to be charged with an increased energy content. The optimization of the charge distribution achieved by the cell connector according to the present invention can improve the overall performance of the battery system. This improvement is particularly achieved in applications requiring a reliable and constant energy supply, such as electric vehicles.

[0039] The flexible film conductor according to the present invention, used as a balancing resistor, achieves very good heat distribution over the entire length of the supply line within the battery. This ensures that balancing does not cause excessive heat, so-called hot spots, to form locally, either in the resistors or locally, such as in the controller or at the locations where the resistors are installed.

[0040] Advantageously, the flexible film conductor according to the present invention can be used as a balancing resistor in such a way that a separate resistor is not required, thereby saving component and assembly costs. Furthermore, it is advantageously possible to achieve significant space savings, for example on a printed circuit board (with the integrated resistor), or to completely avoid the need for flexible film assembly.

[0041] Furthermore, due to avoidable hot spots and by reducing components in the battery management system, for example including flexible thin-film conductors as balancing resistors, a lower risk of failure is achieved, which in turn leads to significant cost savings due to increased durability, lower maintenance costs and repair costs.

[0042] Furthermore, the solution according to the invention of the flexible film conductor makes it possible to advantageously distribute the generated heat via the flexible film conductor, wherein the generated heat is used for preheating the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Embodiments of the present invention are explained in more detail with reference to the drawings and the following description.

[0044] in:

[0045] Figure 1 shows a schematic diagram of a battery management system,

[0046] Figure 2 shows a schematic diagram of a cutout portion of a battery management system,

[0047] Figure 2.1 A schematic diagram showing a meandering flexible thin film conductor,

[0048] Figure 2.2 shows a schematic diagram of a straight flexible thin film conductor, and

[0049] Figure 3 A schematic diagram showing a method for managing charge and / or discharge balance of battery cells. DETAILED DESCRIPTION

[0050] In the following description of embodiments of the present invention, identical or similar elements are denoted by the same reference numerals, wherein a repeated description of these elements is omitted in individual cases. The figures merely schematically illustrate the subject matter of the present invention.

[0051] Figure 1 A schematic diagram of a battery management system 100 is shown. Battery management system 100 includes four battery cells 102, 104, 106, 108, which are connected to a plug connector 110. This connection has five flexible film conductors 122, with each battery cell 102, 104, 106, 108 having a flexible film conductor 122 associated with each battery terminal. Plug connector 110 establishes a physical connection between battery cells 102, 104, 106, 108 and an integrated switching circuit 112. Integrated switching circuit 112 monitors and, if necessary, regulates the voltage of each battery cell 102, 104, 106, 108 so that the voltage of each battery cell 102, 104, 106, 108 is 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. Figure 1 The integrated switching circuit 112 shown in FIG has a filter 114 and a controller 116, wherein the voltage difference of the respective battery cells 102, 104, 106, 108 is checked by the controller 116. The controller 116 has 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. In addition, Figure 1108 , a through current 124 is shown in the form of an arrow, wherein the through current 124 is realized when a voltage difference is detected by the controller 116 at one or more battery cells 102 , 104 , 106 , 108 . When a voltage difference is detected between the battery cells 102 , 104 , 106 , 108 , the controller 116 performs charge and / or discharge balancing by causing a switch 120 in the switch chip 118 to switch the through current 124 flowing through the flexible thin film conductor 122 , thereby performing charge and / or discharge balancing at the one or more battery cells 102 , 104 , 106 , 108 .

[0052] Figure 2 A schematic diagram of a detail 202 of a battery management system 100 is shown, wherein a battery cell 102 and a connection to a plug connector 110 formed by two flexible film conductors 122 are shown.

[0053] Figure 2.1 and Figure 2.2 Two different flexible film conductors are shown as examples. Figure 2.1 This is a meandering conductor guide, ie, exemplarily predetermined conductor guide 204 . 1 , which has a first conductor width, ie, exemplarily predetermined conductor width 206 . 1 , a first conductor length 210 . 1 , and a first conductor thickness 212 . 1 . Figure 2.2 A straight conductor guide, i.e., a predetermined conductor guide 204.2, is shown, which has a second conductor width, i.e., a predetermined conductor width 206.2, a second conductor length 210.2, and a second conductor thickness 212.2. The repeated loops and / or bends of the meandering conductor guide 204.1 can, for example, increase the electrical resistance compared to the straight conductor guide 204.2. Furthermore, the electrical resistance of the flexible film conductor can be adjusted according to the desired electrical resistance by specifically adapting the alternative embodiments of the flexible film conductor by varying the conductor length, conductor thickness, conductor width, conductor guide, and conductor material.

[0054] as from Figure 3 It is apparent that the illustrated embodiment of the method 300 according to the present invention for managing the charge and / or discharge balance of the battery cells 102, 104, 106, 108. Figure 3The illustrated embodiment of a method 300 according to the present invention for controlling charge and / or discharge balancing of battery cells 102, 104, 106, 108 is readily apparent. In a first step, the voltage of each battery cell 102, 104, 106, 108 is monitored 302 by integrated switching circuit 112. In a second step, based on the measured voltage values ​​for each battery cell 102, 104, 106, 108, a decision is made 304 by switching chip 118 in controller 116 to activate one or more flexible thin-film conductors 122, which serve as balancing resistors for charge and / or discharge balancing of battery cells 102, 104, 106, 108. In a third step, charge and / or discharge balancing of each battery cell 102, 104, 106, 108 is activated 306 if the measured voltage difference of each battery cell 102, 104, 106, 108 exceeds a predetermined threshold value. In a fourth step, charge and / or discharge balancing is monitored 308 for each cell 102, 104, 106, 108. A fourth step is then performed, which includes monitoring 308 charge and / or discharge balancing for each cell 102, 104, 106, 108. Finally, a fifth step includes deactivating 310 charge and / or discharge balancing for each cell 102, 104, 106, 108 if the voltage difference of one or more cells is within a predetermined threshold.

[0055] For example, a charge and / or discharge balancing of one or more battery cells 102, 104, 106, 108 can be activated 306 by a switching chip 118 located in the controller 116. In this case, the switching chip 118 can include, for example, switches 120. For example, when a battery voltage threshold is exceeded or undershot, the switching chip 118 is actuated by activating the switches 120 so that the one or more battery cells 102, 104, 106, 108 are discharged and / or charged to a suitable threshold range. If all battery cells 102, 104, 106, 108 have a suitable voltage within the permitted threshold, all switches 120 of the switching chip 118 of the controller 116 are in the open position, so that no charge and / or discharge balancing is performed.

[0056] The invention is not limited to the embodiments described here and the aspects emphasized therein. Rather, numerous variations are possible within the scope of practice of a person skilled in the art within the scope defined by the claims.

Claims

1. A flexible thin film conductor (122) serving as a balancing resistor for charging or discharging balance of battery cells (102, 104, 106, 108), wherein: The flexible thin film conductor (122) is arranged between the battery cells (102, 104, 106, 108) and the integrated switch circuit (112), and the flexible thin film conductor comprises a conductive material, and is characterized in that: - the flexible film conductor (122) has a predetermined conductor guide (204.1, 204.2), and / or - the flexible film conductor (122) has a predetermined conductor width (206.1, 206.2), and / or - the flexible film conductor (122) has a specific conductor thickness (212.1, 212.2), which is designed so that the current required for the charge and discharge balance is generated directly at the flexible film conductor (122), and / or The flexible film conductor (122) has a conductor length (210.1, 210.2), wherein the conductor length (210.1, 210.2) is adapted to the spatial layout between the battery cells (102, 104, 106, 108) and the integrated switching circuit (112).

2. The flexible film conductor (122) according to claim 1, wherein The conductive material is selected from the group consisting of nickel, tin or brass.

3. The flexible film conductor (122) according to claim 1, wherein The conductive material comprises an alloy material, wherein the alloy material is selected from the group consisting of nickel, tin or brass.

4. The flexible film conductor (122) according to any one of the preceding claims, wherein The wire thickness (212) is constant along the entire wire length (210).

5. The flexible film conductor (122) according to any one of the preceding claims, wherein The wire guide (204) has a straight wire guide (204.2) or a meandering wire guide (204.1) with repeated loops and / or bends, wherein the meandering wire guide (204.1) is used to increase the electrical resistance compared to the straight wire guide (204.2).

6. The flexible film conductor (122) according to any one of the preceding claims, wherein The flexible film conductor (122) has a variable resistance, wherein the resistance can be set by selecting the conductive material.

7. A battery management system (100), comprising: - a plurality of battery cells (102, 104, 106, 108), wherein the battery cells (102, 104, 106, 108) are connected in series, - an integrated switching circuit (112), wherein the integrated switching circuit (112) comprises at least: i. one or more plug connectors (110), wherein the one or more plug connectors (110) comprise a physical connection between each battery cell (102, 104, 106, 108) and the integrated switching circuit (112), ii. one or more filters (114), wherein the one or more filters (114) are configured to minimize noise in the measured voltage value, and iii. One or more controllers (116) with integrated switch chips (118) that make decisions based on the measured voltage value differences, - wherein each battery terminal of the battery cells (102, 104, 106, 108) is connected to the plug connector (110) via a flexible film conductor (122), wherein the flexible film conductor (122) is designed as a balancing resistor for charging or discharging balancing of the battery cells (102, 104, 106, 108), wherein the flexible film conductor (122) is activated if a voltage difference exceeding a predetermined threshold value is detected between the battery cells (102, 104, 106, 108) in the one or more controllers (116).

8. A method (300) for managing charge and / or discharge balance of battery cells (102, 104, 106, 108) using the battery management system (100) according to claim 7, the method comprising the following steps: a. monitoring (302) the voltage of each cell (102, 104, 106, 108) by means of the integrated switching circuit (112), b. Based on the measured voltage values ​​of the respective battery cells (102, 104, 106, 108), a decision (304) is made via a switch chip (118) in the controller (116) on activation of the one or more flexible thin film conductors (122), the flexible thin film conductors serving as balancing resistors for charge and / or discharge balancing of the battery cells (102, 104, 106, 108); c. activating (306) charge and / or discharge balancing of the one or more battery cells (102, 104, 106, 108) if the measured voltage difference of the one or more battery cells (102, 104, 106, 108) exceeds a predetermined threshold, and d. monitoring (308) the charge and / or discharge balance for each cell (102, 104, 106, 108), and e. If the voltage difference is within a predetermined threshold value, deactivating ( 310 ) the charge and / or discharge balancing for each cell ( 102 , 104 , 106 , 108 ) is performed.

9. Use of the battery management system (100) according to claim 7, so as to achieve adaptive control and uniform load distribution of the flexible thin film conductor (122), thereby extending battery life.

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