Battery module and battery pack comprising same

Abstract

The utility model relates to a battery module and a battery pack comprising the same. The battery module includes a plurality of battery cells stacked in a longitudinal direction and a flexible interconnect configured to provide electrical information of the battery cells to a battery management unit. The flexible interconnect extends in a longitudinal direction and is secured to the plurality of battery cells, and includes a stress relief section that includes a plurality of interconnect traces and extends in the longitudinal direction. The stress relief section has a cutout extending in the longitudinal direction that separates adjacent interconnect traces from each other. The interconnect traces include a first peripheral interconnect trace forming a recessed portion and a second peripheral interconnect trace opposite the first peripheral interconnect trace and forming a protruding portion. A height of the protruding portion in the stress relief section is the same dimension as or less than a width of the flexible interconnect adjacent to the stress relief section.

Description

Technical Field

[0001] Various aspects of the embodiments disclosed herein relate to battery modules. Background Technology

[0002] Recently, vehicles that use electricity as a power source (e.g., vehicles used to transport goods and people) have been developed. Such electric vehicles are automobiles propelled by an electric motor using energy stored in a rechargeable (or secondary) battery. Electric vehicles can be powered solely by batteries, or they can be hybrid vehicles powered by, for example, a gasoline generator (e.g., a vehicle may include a combination of an electric motor and a conventional internal combustion engine). Generally, an electric vehicle battery (EVB) (or traction battery) is a battery used to power the propulsion of a battery electric vehicle (BEV). Electric vehicle batteries differ from starter batteries, lighting batteries, and ignition batteries because they are designed to provide (or output) electricity for a continuous period of time. A rechargeable (or secondary) battery differs from a primary battery in that it is designed to be repeatedly charged and discharged, while the latter provides an irreversible conversion of chemical energy into electrical energy. Low-capacity rechargeable batteries can be used as power sources for small electronic devices such as mobile phones, laptops, and cameras, while high-capacity rechargeable batteries can be used as power sources for hybrid vehicles, etc.

[0003] Generally, a rechargeable battery pack includes an electrode assembly, a casing that receives (or houses) the electrode assembly, and electrode terminals electrically connected to the electrode assembly, which includes a positive electrode, a negative electrode, and a separator inserted between the positive and negative electrodes. An electrolyte solution is injected into the casing to enable the battery to be charged and discharged via an electrochemical reaction between the positive and negative electrodes and the electrolyte solution. The shape of the casing (such as cylindrical or rectangular) can vary depending on the intended use of the battery. Lithium-ion (and similar lithium polymer) batteries (widely known for their use in laptops and consumer electronics) are the most common type of battery used to power the latest electric vehicles under development.

[0004] Rechargeable batteries can be used as part of a battery module comprising (or formed from) multiple individual battery cells, which are connected in series and / or in parallel to provide high energy density, such as for electric motor drives in hybrid vehicles. For example, a battery module can be formed by interconnecting the electrode terminals of multiple individual battery cells (the number of individual battery cells depends on the desired capacity) to achieve a high-power rechargeable battery.

[0005] Battery modules can be constructed using either a block design or a modular design. In a block design, each battery cell is integrated into a common current collector structure and a common battery management system, and the units are arranged within a housing. In a modular design, multiple battery cells are connected to form sub-modules, and several sub-modules are connected to form a battery module. In automotive applications, battery systems typically consist of multiple battery modules connected in series to provide a desired voltage. A battery module may include sub-modules with multiple stacked battery cells, each stack may include parallel-connected cells (XpYs) or series-connected cells (XsYp) connected in parallel in sequence.

[0006] A battery pack is a group of any number (typically identical) battery modules. They can be configured in series, parallel, or a combination of both to provide a desired voltage, capacity, or power density. A battery pack includes individual battery modules and interconnects that provide conductivity between them.

[0007] A battery system may include a battery management system (BMS), which is a suitable electronic system configured to manage rechargeable batteries, battery modules, and battery packs, such as by protecting rechargeable batteries from operation outside their safe operating areas, monitoring their status, calculating secondary data, reporting that data, controlling their environment, validating them, and / or balancing them. For example, a BMS may monitor the status of a rechargeable battery, which is represented by: voltage (e.g., the total voltage of the battery pack or battery module and / or the voltage of individual cells), temperature (e.g., the average temperature of the battery pack or battery module, coolant inlet temperature, coolant outlet temperature, and / or the temperature of individual cells), coolant flow (e.g., flow rate and / or coolant pressure), and current. In addition, the BMS can calculate the following values ​​based on the above parameters, such as minimum and maximum cell voltage, state of charge (SOC) or depth of discharge (DOD) indicating the battery's charge level, state of health (SOH; a measurement of the percentage of the battery's original capacity with various definitions), state of power (SOP; the amount of electricity available within a defined time interval, taking into account current power usage, temperature, and other conditions), state of safety (SOS), maximum charging current as charge current limit (CCL), maximum discharging current as discharge current limit (DCL), and cell internal impedance (e.g., used to determine open-circuit voltage).

[0008] A Battery Management System (BMS) can be centralized, where a single controller is connected to the battery cells via multiple wires. In other cases, the BMS can be distributed, with the BMS board mounted at each cell and only one communication cable between the battery and the controller. Still others, the BMS can have a modular construction comprising several controllers, each handling a certain number of cells (e.g., a group of cells), while communicating with each other. Centralized BMS is the most economical but the least scalable and suffers from the need for multiple wires. Distributed BMS is the most expensive but the simplest to install and offers the cleanest components. Modular BMS offers a trade-off between the characteristics and disadvantages of the other two topologies.

[0009] A Battery Management System (BMS) can protect a battery pack from operating outside its safe operating zone. Operating outside the safe operating zone can be indicated by overcurrent, overvoltage (e.g., during charging), overtemperature, undertemperature, overpressure, and ground fault or leakage current detection. A BMS can prevent operation outside the battery's safe operating zone by: including internal switches (e.g., relays or solid-state devices) that open if the battery operates outside its safe operating zone; requiring devices connected to the battery to reduce or even terminate their use of the battery; and / or actively controlling the environment, such as through heaters, fans, air conditioning, or liquid cooling.

[0010] Static control of battery power output and charging may be insufficient to meet the dynamic power demands of various electrical devices connected to the battery system. Therefore, a stable information exchange can be employed between the controllers of the battery system and the electrical devices. This information can include the battery system's actual state of charge (SoC), potential electrical performance, charging capacity, and internal resistance, as well as the actual or predicted power demand or remaining capacity of the electrical devices. Thus, the battery system can include a battery management system (BMS) for acquiring and processing this information at the system level, and may also include multiple battery module managers (BMMs) that are part of the battery modules of the system and acquire and process relevant information at the module level. The BMS measures system voltage, system current, local temperatures at different locations within the system housing, and insulation resistance between live components and the system housing, while the BMMs can measure the individual cell voltages and temperatures of the battery cells within the battery modules.

[0011] BMS / BMM (also known as Battery Management Unit (BMU)) manages the battery pack by protecting the battery from operating outside its safe operating area (or safe operating parameters), monitoring its status, calculating secondary data, reporting that data, controlling its environment, validating it, and / or balancing it.

[0012] To manage or control the individual cells in a battery module or battery pack, several types of interconnections are used. The first type of interconnection is called a busbar, which connects two or more terminals of a battery cell to provide a parallel or series configuration of the cells. Due to their nature of supplying current to / from cells, busbars are solid and suitable for conducting high currents. Busbars can have a strip shape with a large surface area. A large surface area can carry a large amount of current. In most applications, busbars are passive components and can be fitted even in very small and confined installation spaces, but in some cases, they can be active components.

[0013] The second type of interconnect involves signal lines or conductors used to transmit electrical information from a single cell or sub-module to the BMS / BMU. Due to their signal-carrying nature, these lines can be flexible (e.g., they can be implemented as flexible interconnects, such as flexible printed circuits (FPCs)). Flexible interconnects are used inside battery modules to connect the battery cell terminals to the battery management unit. Flexible interconnects can extend over busbars, and in this case, the busbars should have very smooth edges and surfaces, which is difficult to achieve and inspect. Flexible interconnects can be formed as a stack of an insulating (or insulating) substrate material, a copper layer (from which multiple conductive traces or signal lines can be formed), and an insulating capping layer. The substrate and capping materials can have relatively good isolation properties, adequately isolating the signal lines while being relatively thin, such as in the tens of micrometers range. This insulating capping layer can be a thin layer of a mechanically durable insulating material (such as polyimide (PI)). Although the insulating material is mechanically durable, due to its small thickness, it needs to be protected from hazards such as sharp edges, rough surfaces, stress, etc. In other words, this durability is limited by the layer thickness; that is, a very thin layer with a thickness of a few micrometers is fragile. Because it is desirable to monitor individual terminals and typically a large number of individual terminals, flexible interconnects can have a relatively large number of conductive traces, with each trace connecting to either an individual terminal or a busbar. In some cases, individual terminals can be connected to busbars, which gives all connected individual terminals the same potential. In this sense, flexible interconnects can be connected to busbars to obtain the potential of the individual terminals. If all potentials of all individual terminals are known, then the voltage of each individual terminal is also known.

[0014] When flexible interconnects are used to measure / balance cell voltage, they mechanically interconnect battery cells or busbars. Over time, primarily due to aging, cells may expand; therefore, cells should be able to increase in size. This dimensional change can be accounted for when designing flexible interconnects, allowing them to appropriately compensate for variations in distance between two fixed points. In other words, the volume of a battery cell's package may increase, leading to movement of the individual cell relative to another adjacent cell. Furthermore, depending on the battery module's usage, such as in vehicles, movement between cells may be caused by vibration. Therefore, since flexible interconnects are typically arranged on top of busbars, the possibility of cell expansion can be considered when designing them.

[0015] This can be achieved using different methods. One approach to compensate for length variations involves using an additional length and forming a waveform in the z-direction (e.g., the vertical direction), but this leads to assembly difficulties. Another approach involves creating a 2D shape for each individual interface, but this results in more waste and cannot precisely position the interconnects. In examples of related technologies, flexibility is achieved by using an Ω shape in the z-direction of the flexible interconnect; one example is... Figure 2 As shown in the image. For example, Figure 2 A typical implementation of a flexible interconnect according to related technologies is shown, with its top surface shown in a perspective view. For example, the vertical protrusions are easily identifiable, having the aforementioned Ω shape in the z-direction. Pad mounting portions for pads or tabs can be provided to extend longitudinally in the middle of the flexible interconnect. This design is difficult to manufacture, and positioning the tabs for connecting the flexible interconnect to the busbar with good precision in a dedicated area is challenging. The waveform or Ω shape relaxes after the flexible interconnect is manufactured and is typically shipped to the packassembly in a completely flat state. Therefore, a second manual placement is the only possible solution, but this carries the risk of damaging the flexible interconnect due to compression and scratching of the sharp edges of the busbar. Additional plastic parts have been designed and manufactured for the assembly process. The flexible interconnect is always under stress after the solder joints are fixed. While it is desirable to allow automated assembly of the flexible interconnect by using, for example, robotic arms, such automated assembly is incompatible with the Ω-shaped flexible interconnect.

[0016] An alternative to the Ω shape in the z-direction is a flat double S-shape, such as in, for example... Figure 3 As shown in the image. Figure 3 This is a top view of flexible interconnects based on related technologies. (Instead of...) Figure 2The Ω shape shown in the z-direction has a stress-relief section that is flat and does not extend in the z-direction, but rather forms a double S-shape within the plane of the flexible interconnect. However, the S-shape requires increasing (e.g., doubling) the width of the flexible interconnect, which would require twice the space in the battery module or battery pack and result in more material being cut away (e.g., wasted) during production. This increased material waste refers to the fact that flexible interconnects are typically formed from a single piece of material, and if the final shape of the flexible interconnect has a certain width, the raw material must have at least the same width. Therefore, a large portion of the raw material will be cut away as scrap.

[0017] Another related technical design includes a battery module with busbars, a circuit board, and connectors connecting the circuit board to the busbars. In this design, all connectors are individually mounted on a circuit board located in the middle of the upper side of the battery module. For example, the connectors have buffer sections with weight-reducing holes (which reduce bending, compressive, and tensile strength), allowing deformation and providing good cushioning. S-shaped, Ω-shaped, and Z-shaped buffer sections can be used. However, all of these shapes significantly increase the width of the structure, leading to the aforementioned problems such as increased space requirements and more material cut-off (e.g., more waste). Utility Model Content

[0018] The embodiments of this disclosure provide a more reliable and compact cell contact structure. Furthermore, automated assembly is possible, reducing waste and thus lowering costs. This is achieved by providing flexible interconnects with flat stress-relief sections. Moreover, the width of the flexible interconnects is normal, i.e., not significantly increased. Furthermore, cost-effective material use is achieved by reducing material cut-off.

[0019] This disclosure is defined by the appended claims and their equivalents. The following description is subject to this limitation. Any disclosure outside the scope of the claims and their equivalents is intended for illustrative and comparative purposes.

[0020] According to an embodiment of this disclosure, a battery module includes: a plurality of battery cells stacked along a longitudinal direction; and a flexible interconnect configured to provide electrical information of the plurality of battery cells to a battery management unit. The flexible interconnect extends in the longitudinal direction and is fixed to the plurality of battery cells. The flexible interconnect includes stress-relief sections comprising a plurality of interconnect traces extending in the longitudinal direction. The stress-relief sections have cutouts extending in the longitudinal direction and separating adjacent interconnect traces among the plurality of interconnect traces. The plurality of interconnect traces includes a first peripheral interconnect trace forming a recessed portion and a second peripheral interconnect trace opposite to the first peripheral interconnect trace forming a protruding portion. The height of the protruding portion in the stress-relief section is the same as or smaller than the width of the flexible interconnect adjacent to the stress-relief section.

[0021] The stress relief zone can be flat.

[0022] The cut can be non-linear.

[0023] The height of the protrusion in the stress relief section can be the same as or less than the width of one of the interconnecting traces.

[0024] The width of the flexible interconnect adjacent to the stress relief section can be equal to the width of the flexible interconnect in the stress relief section.

[0025] The flexible interconnect may also include a pad mounting portion for mounting pads that are connected to one of the cell units. The pad mounting portion may be located outside the stress-relief section at the edge of the flexible interconnect extending in the longitudinal direction.

[0026] The stress relief zone can be symmetrical about an axis perpendicular to the longitudinal direction and passing through the center of the stress relief zone.

[0027] At least two of the multiple interconnect traces can have the same width.

[0028] The cut can include multiple non-linear cuts, each with the same width.

[0029] Each nonlinear cut can have a tortuous shape, a wavy shape, an Ω-shaped shape, a V-shaped shape, or a W-shaped shape.

[0030] Flexible interconnects can also include conductor lines.

[0031] The stress relief section may also include conductor lines.

[0032] Each interconnecting trace may also include conductor lines.

[0033] Flexible interconnects can be flexible printed circuits.

[0034] According to embodiments of this disclosure, a battery pack includes a plurality of battery modules described herein.

[0035] Additional aspects and features of this disclosure may be understood from the dependent claims or the following description. Attached Figure Description

[0036] The aspects and features of this disclosure will become apparent to those skilled in the art from the detailed description of embodiments thereof with reference to the accompanying drawings, in which:

[0037] Figure 1 A schematic partial perspective view of a battery module according to related technologies is shown.

[0038] Figure 2 A schematic partial perspective view showing a flexible interconnect according to related technologies.

[0039] Figure 3 A top view of another flexible interconnect based on related technologies is shown.

[0040] Figure 4 A top view of a flexible interconnect according to an embodiment of the present disclosure is shown.

[0041] Figure 5 Show Figure 4 The top view of the flexible interconnect shown illustrates the stress relief section.

[0042] Figure 6 A top view of a stress relief section according to another embodiment of the present disclosure is shown.

[0043] Figure 7 A top view of a stress relief section according to another embodiment of the present disclosure is shown. Detailed Implementation

[0044] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. Aspects and features of the embodiments and methods of implementation thereof will be described with reference to the drawings. However, this disclosure may be implemented in a variety of different forms and should not be construed as being limited to the embodiments shown herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete and will fully convey the aspects and features of this disclosure to those skilled in the art.

[0045] It will be understood that when an element or layer is referred to as being "on," "connected to," or "bonded to" another element or layer, it can be directly on, directly connected to, or directly bonded to the other element or layer, or there may be one or more intermediary elements or layers. When an element or layer is referred to as being "directly on," "directly connected to," or "directly bonded to" another element or layer, there are no intermediary elements or layers. For example, when a first element is described as being "bonded" or "connected" to a second element, the first element can be directly bonded to or connected to the second element, or the first element can be indirectly bonded to or connected to the second element via one or more intermediary elements.

[0046] In the accompanying drawings, the dimensions of various elements, layers, etc., may be exaggerated for clarity of illustration. The same reference numerals refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, when describing embodiments of this disclosure, the use of "may" refers to "one or more embodiments of this disclosure." Expressions such as "at least one of..." and "any one of..." modify the entire list of elements when following a list, but not individual elements in the list. For example, the expression "at least one of a, b, or c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. As used herein, the terms "use," "using," and "used" can be considered synonymous with the terms "utilize," "utilizing," and "utilized," respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms rather than terms of degree, and are intended to take into account the inherent variations in the measured or calculated values ​​that will be recognized by one of ordinary skill in the art.

[0047] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or segment from another element, component, region, layer, or segment. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment.

[0048] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature as shown in the accompanying drawings and another element or feature (or other elements or features). It will be understood that, in addition to the orientations depicted in the drawings, the spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as “below” or “under” other elements or features will be oriented “above” or “above” other elements or features. Therefore, the term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly.

[0049] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit this disclosure. As used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly indicates otherwise. It will also be understood that, when used in this specification, the terms “include,” “including,” “comprise,” and / or “comprising” indicate the presence of the stated feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0050] The electrical connections or interconnections described herein may be provided by conductive elements, such as those on a PCB or another circuit carrier. Conductive elements may include metallizations (such as surface metallizations) and / or leads, and / or may include conductive polymers or ceramics.

[0051] According to embodiments of this disclosure, a battery module includes a plurality of battery cells and a flexible interconnect for providing electrical information of the plurality of battery cells to a battery management unit (BMU). The flexible interconnect has an elongated shape in the longitudinal direction of the battery module, defining the longitudinal direction of the flexible interconnect. As used herein, "elongated" means having a width and a length, wherein the length is greater than the width, for example, the length is twice the width, ten times the width, or 20 times the width, etc. The flexible interconnect is fixed to at least one battery cell. Furthermore, the flexible interconnect includes at least one flat stress-relief section extending along the longitudinal direction of the battery module. The at least one flat stress-relief section includes at least one non-linear (e.g., curved) cut extending along the longitudinal direction of the flexible interconnect. At least one cut refers to, for example, a longitudinal opening or hole that begins at the top side and ends at the bottom side (e.g., extends completely through the thickness of the flexible interconnect). For example, at least one cut may be a through-hole. Non-linearity, for example, means that two points "A" and "B" are not connected by a straight line, but are connected in an indirect manner. This connection may be curved or may include an edge. These points can be connected by two intersecting (e.g., converging) lines. Multiple interconnecting traces are separated from each other by at least one non-linear cut. Two interconnecting traces are formed immediately adjacent to each cut.

[0052] Embodiments of this disclosure relate to a novel relaxed scalable element formed between solid flexible interconnects by using (or including) cutouts or slots. This can be achieved by forming several parallel double S-shapes (having a width smaller than the normal (e.g., average) width of the flexible interconnect) to simultaneously allow for relative longitudinal extension and a flat design between the solid portions of the flexible interconnect.

[0053] Therefore, a particularly compact design for flexible interconnects is provided, which is slender (e.g., narrow in width) and flexible in the longitudinal direction. Flexibility refers to the ability to be compressed and stretched. Compression can also be referred to as compressive stress. Tension or expansion can also be referred to as tensile stress. Compression and tension can occur repeatedly.

[0054] The embodiments shown in the accompanying drawings will be described in detail below.

[0055] Figure 1 A battery module 1 according to related technology is shown. Figure 1This is a partial perspective view of the upper surface of the battery module 1, in which multiple battery cells 2 are arranged parallel to each other along the longitudinal direction of the battery module 1. The multiple battery cells 2 are connected to each other via busbars 30. The busbars 30 connect to the terminals 3 of the battery cells 2. For example, two adjacent battery cells 2 are connected via busbars 30. A first portion of the busbar 30 extends along the longitudinal direction of the battery cells 2, on top of the battery cells 2 and parallel to the battery cells 2, and two of the first portions are connected to one busbar 30. For example, the busbar 30 extends in the stacking direction of the battery cells. Therefore, in... Figure 1 In the accompanying drawings, reference numeral 30 denotes the first two busbars. Busbar 30 may have a flat structure. On the top of the busbar 30, pads 40 are arranged to connect to the flexible interconnect 10. The flexible interconnect 10 extends longitudinally along the battery module 1. For example, each of the six busbars 30 has one pad 40, and they are all connected to the same flexible interconnect 10. Therefore, the flexible interconnect 10 has at least six signal lines. The number of signal lines formed on the flexible interconnect 10 is equal to the number of busbars 30 connected to the flexible interconnect 10.

[0056] Figure 2 This is a perspective view of the upper surface of the flexible interconnection of the battery cell contact structure according to related technologies. For example, Figure 2 A flexible interconnect 10 and an FPC 12 according to related technologies are shown. The flexible interconnect 10 has mounting holes 17 on its sides, providing allowance for adjustment when the flexible interconnect 10 is installed. A pad mounting portion 19 may be provided in the middle of the flexible interconnect 10. For example, the flexible interconnect 10 is connected to the busbar 30 via pads or tabs at the pad mounting portion 19 (e.g., see...). Figure 1 ) or single terminal 3 (for example, see Figure 1 The signal lines used to transmit electrical information from the battery cell 2 to the battery management system are located on the bottom of the flexible interconnect 10. For example, the stress relief section 20 is formed to extend in the vertical direction, such that the flexible interconnect 10 is not flat. At least one stress relief section 20 may be located between two pad mounting portions 19.

[0057] Figure 3This is a partial top view of a stress-relief section 20 on the upper surface of a flexible interconnect 10 designed for flatness, according to related art. The flexible interconnect 10 has a width 'a' at its leftmost and rightmost points, and within the stress-relief section 20, a protruding portion 26 with a protrusion height 'b' and a recessed portion 25 on the edge of the flexible interconnect 10 opposite to the protrusion 26. Throughout this disclosure, the height 'b' is defined and / or measured from the outer edge of the flexible interconnect 10 (which is parallel to the longitudinal direction in which the flexible interconnect 10 extends and is located on one side of the flexible interconnect 10 in the same direction as the protrusion of the protrusion 26) to a tangent tangent to and away from the outer edge of the protrusion 26 and parallel to the outer edge of the flexible interconnect 10. According to related art, the height 'b' of the protrusion is significant, indicating that the value of the height 'b' of the protrusion is at least close to, or much greater than, the width 'a' of the flexible interconnect 10. Therefore, the depth 'c' of the recessed portion 25 significantly exceeds the width 'a' of the flexible interconnect 10. For example, the distance from the inflection point of the recessed portion 25 to the inner edge of the flexible interconnect 10 (which is parallel to the longitudinal direction of the flexible interconnect 10 and located on the side of the flexible interconnect 10 opposite to the protrusion direction of the protrusion 26) exceeds the width a of the flexible interconnect. This results in an increase in the total width of the flexible interconnect 10, which is width a plus height b. Therefore, according to Figure 3 The production of this flexible interconnect 10 requires cutting off a large amount of material on the left and right sides of the stress relief section 20, because the flexible interconnect 10 is usually formed monolithically.

[0058] about Figures 4 to 7 The reference numerals used in the accompanying drawings can indicate the relationship between the figures and the figures related to the figures. Figures 1 to 3 The same reference numerals in the attached figures refer to different structures. Figure 4 and Figure 5 This is a top view showing the top side of a flexible interconnect 10 (e.g., FPC 12) according to some embodiments of this disclosure. (Refer to...) Figure 4 and Figure 5 According to some embodiments of this disclosure, the flexible interconnect 10 may be linear and may include stress-relief sections 20, which may be referred to as stress-regulating sections. The stress-relief section 20 may include a structure configured to absorb stress. This structure may include nonlinear cutouts 23 and interconnect traces 24, which will be described in detail below. Main sections 21 of the flexible interconnect 10 may be defined at both ends (e.g., opposite ends) of the stress-relief section 20. The main sections 21 have a width a. i Furthermore, in some embodiments, the flexible interconnect 10 extends in the longitudinal direction. The width a of the flexible interconnect 10 in the stress relief section 20 is... s The width a of the flexible interconnect 10 in the main segment 21 is less than or equal to the width a. i The width a of the stress relief section 20s Excluding the void or depth c formed by the recessed portion 25. The stress relief section 20 is terminated by external interconnect traces 24a and 24b (e.g., at least two external interconnect traces 24a and 24b, which will be described later). The longitudinal direction of the flexible interconnect 10 may be the same as, but is not limited to, the stacking direction of the battery cells 2. Width a i and / or a s It can be in the range of approximately 2mm to approximately 20mm, approximately 4mm to approximately 15mm, or approximately 6mm to approximately 10mm. For example, width a i and / or a s The width can depend on the number of battery cells 2 (or can be determined based on the number of battery cells 2), for example, based on the number of busbars 30 that must be connected by flexible interconnects 10. A width of approximately 2mm may be sufficient for small battery modules. A width of approximately 20mm may be sufficient for large applications. Although... Figure 4 The main segment 21 of the flexible interconnect 10 shown is relatively short, but this disclosure is not limited thereto. In other embodiments, the main segment 21 may span a distance longer than the stress relief segment 20 and / or a multiple thereof. A pad mounting segment 22 may be adjacent to the main segment 21, where pads 40 may be mounted to the flexible interconnect 10 at pad mounting portions 19 for connecting the flexible interconnect 10 to the busbar 30 via the pads 40. For example, the pad mounting segment 22 may have a greater width than the main segment 21. The pad mounting segment 22 may have the same or substantially the same width as the main segment 21 or the same or substantially the same width as the stress relief segment 20. For example, in an embodiment where the pad mounting segment 22 is directly attached to the stress relief segment 20, the main segment 21 may also be a portion of the flexible interconnect 10 on the side of the pad mounting segment opposite to the stress relief segment 20. For example, a "main segment" can refer to a segment of the flexible interconnect 10 that extends longitudinally and has its main width without any recesses or protrusions. The flexible interconnect 10 may have a rectangular shape in the main segment 21. The main width refers to the width of the flexible interconnect 10 in a segment that is different from the pad mounting segment 22 and different from the stress relief segment 20. For example, more than about 80% of the flexible interconnect 10 has this main width.

[0059] In another embodiment, the stress-relief section 20 may be displaced relative to adjacent sections (e.g., main section 21 and / or pad mounting section 22). Displacement refers to movement or arrangement relative to the longitudinal direction of the flexible interconnect 10, and the stress-relief section 20 may move away from the original longitudinal direction in the same plane as the flexible interconnect 10. For example, the stress-relief section 20 may move perpendicular to the longitudinal direction of the flexible interconnect 10. However, the flexible interconnect 10 remains continuous.

[0060] Figure 5 The stress relief section 20 is shown in more detail. In some embodiments, the stress relief section 20 may include two nonlinear cuts 23 extending along the longitudinal direction of the flexible interconnect 10. The longitudinal extension of the nonlinear cuts 23 may be nonlinear. Nonlinearity means that the two points are not connected by a straight line. In other words, they are connected in a roundabout way. The nonlinear cuts 23 may be curved and may have a meandering shape, or may include two or more straight lines with intersections between them. Meandering riverbeds are common in nature and form well-known shapes. The shape of the stress relief section 20 may also be Ω-shaped, where the legs of the Ω are partially stretched. Although the Ω shape is almost circular, the circular shape flattens out when the lower straight portion is stretched, and can form Figure 4 and Figure 5The shape is shown in the figure. The nonlinear cut 23 has a width e. The stress-relief section 20 may have at least two nonlinear cuts 23. In some embodiments, the width e of each nonlinear cut 23 is the same. In another embodiment, the width e of at least two nonlinear cuts 23 is the same. The width e may be constant over the entire length of the nonlinear cut 23, or it may vary. A nonlinear cut 23 divides the flexible interconnect 10 into at least two interconnect traces 24. For example, the stress-relief section 20 may have two outer interconnect traces 24a and 24b on its edge. The outer contour of the first outer interconnect trace 24a may form a recessed portion 25. The outer contour of the second outer interconnect trace 24b, opposite to the first outer interconnect trace 24a, may form a protruding portion 26. In the illustrated embodiment, three interconnect traces 24 are formed by two nonlinear cuts 23. In other words, n nonlinear cuts 23 form n+1 interconnect traces 24. The interconnect traces 24 may have a width d. For example, at least two of the interconnect traces 24 have the same width d. All interconnect traces 24 may have the same or substantially the same width d, or may have different widths or varying widths. For example, the outer (or peripheral) interconnect traces 24a and 24b may have the largest width, and each inner interconnect trace 24c may have a smaller width. For example, the outer interconnect traces 24a and 24b may have a smaller width than each inner interconnect trace 24c. This will create flexibility toward the interconnect traces 24 with smaller widths. The width d may range from about 1 mm to about 10 mm, about 2 mm to about 8 mm, or about 3 mm to about 5 mm. A width of about 1 mm provides sufficient strength and is the most flexible. At the other end of this range, a width of about 10 mm provides very good strength while still being sufficiently flexible. The axis of symmetry S extends through the middle of the stress-relief section 20. The flexible interconnect 10 may be symmetrical about the axis of symmetry S. The axis of symmetry S may be an axis perpendicular to the longitudinal direction and may pass through the center (or center point) of the stress-relief section 20. The nonlinear cut 23 can be S-shaped. Since the S-shape extends in two opposite directions on either side of the axis of symmetry S, this shape cut can be called a double S-shaped cut. For example, both the nonlinear cut 23 and the interconnecting trace 24 can be double S-shaped. For example, the shapes of the nonlinear cut 23 and / or the interconnecting trace 24 can extend parallel to each other. Even if they can extend parallel to each other, they can have different dimensions and / or lengths, such as... Figure 5 As shown, the first external nonlinear cut 23a is shorter than the second external nonlinear cut 23b in the longitudinal direction of the flexible interconnect 10. In other embodiments, the nonlinear cuts 23 may have all or part of the same or substantially the same length. Furthermore, as... Figure 4 and Figure 5As shown, the second external nonlinear cut 23b may have a longer linear portion near the axis of symmetry S than the linear portion of the first external nonlinear cut 23a.

[0061] Because the nonlinear cut 23 extends nonlinearly, the recessed portion 25 and the protruding portion 26 are formed in the flexible interconnect 10. When the force F is along the width direction of the flexible interconnect 10 (see example...), Figure 4 When the longitudinal arrow (in the diagram) acts on the outer end of the stress-relief section 20 or the outer end of the flexible interconnect 10, this tension can cause deformation of the stress-relief section 20. This means that the force F can cause intentional (or anticipated) deformation of the stress-relief section 20. For example, stress can be concentrated in the stress-relief section 20 and can prevent or significantly reduce uncontrolled deformation of other parts of the flexible interconnect 10. For example, in the case of compressive stress that may be caused by movement m1 at both ends of the stress-relief section 20, one or more interconnect traces 24 may deform, for example, by reactive movement rm1, and the longitudinal ends of the stress-relief section 20 may move toward each other in the longitudinal direction of the flexible interconnect 10. Thus, the stress-relief section 20 is compressed, and the height b of the protrusion 26 can increase. For example, in the case of tensile stress that may be caused by movement m2, the interconnect traces 24 may deform, for example, by reactive movement rm2, and the longitudinal ends of the stress-relief section 20 move away from each other. Therefore, the stress-relief section 20 becomes flat, meaning the height b of the protrusion 26 can be reduced. In the previous example, all deformation occurred in the same plane as the plane in which the flexible interconnect 10 extends. Therefore, the deformation of the flexible interconnect 10 in the vertical direction (e.g., the direction perpendicular to the longitudinal direction of the flexible interconnect 10 and perpendicular to the width of the flexible interconnect 10) is minimal or zero. Figure 5 In the embodiment shown, the recessed portion 25 may be formed immediately adjacent to the first external interconnect trace 24a. In some embodiments, the recessed portion 25 may have a rounded shape, such as a circle or an ellipse. The recessed portion 25 has a depth c. The depth c may be less than the width a of the flexible interconnect. i For example, width c can be found from approximately a. i / 2 to the width d of the interconnect trace 24. The protrusion 26 may be formed on the opposite side of the recess 25 (e.g., on the opposite side in a direction perpendicular to the extension direction of the flexible interconnect 10). The protrusion 26 has a height b. In one embodiment, the height b and depth c may be the same or substantially the same. The recess 25 and the protrusion 26 refer to portions of the flexible interconnect 10 and define the external shape of the flexible interconnect 10. According to some embodiments of this disclosure, the height b of the protrusion 26 is equal to or less than the width a of the flexible interconnect 10 adjacent to the stress relief section 20. iAccording to some embodiments of this disclosure, the width a of the flexible interconnect 10 in the stress relief section 20 is... S The width a of the flexible interconnect 10 in the main segment 21 may be no greater than or equal to the width a. i The width a of the flexible interconnect 10 in the stress relief section 20 S The measurement can be taken from the tangent of the nonlinear outer edge of the first external interconnect trace 24a (which is parallel to the longitudinal direction of the flexible interconnect 10 and away from the nonlinear cut 23) to the tangent of the opposite outer edge of the second external interconnect trace 24b (which is parallel to the longitudinal direction of the flexible interconnect 10 and away from the nonlinear cut 23). In the stress relief section 20, when the outer edge of the flexible interconnect 10 on the recessed portion 25 side is taken as the baseline, the total width of the flexible interconnect 10 in the stress relief section 20 is width a. i Add the height b, where the width a i The width (also called the main width) of the flexible interconnect 10 in the main segment 21 is referred to as a, and the height b refers to the width of the protruding portion 26 (which extends beyond the flexible interconnect 10 in the main segment 21). In other words, the total width of the flexible interconnect 10 is width a. i Including the height b. In some embodiments, the height b of the protrusion 26 can be equal to the width d of the interconnect trace 24. In some embodiments, the height b of the protrusion 26 can be less than the width d of the interconnect trace 24. For example, the height b of the protrusion 26 in the stress relief section 20 can be no greater than the width d of an interconnect trace 24. The smaller the height b of the protrusion 26, the more compact the flexible interconnect 10 will be. For example, the smaller the height b of the protrusion 26, the less material needs to be cut off. On the other hand, the recess 25 does not directly affect the height b of the protrusion 26, but only defines the depth c. Therefore, in some embodiments, if the height b of the protrusion 26 is less than the depth c, the width a of the flexible interconnect 10 in the stress relief section 20 will be less than the depth c. s It can be less than the width a of the flexible interconnect 10 i For example, if the width a of the stress relief section 20 is... s If the width a of the stress relief section 20 is sufficient to accommodate all signal lines, then... S It can be less than the width a of the flexible interconnect 10 i .

[0062] Figure 6 Another flexible interconnect 10 according to some embodiments of this disclosure is shown. For example, Figure 6 This is a top view of stress relief section 20, similar to... Figure 5As shown in the diagram. In this embodiment, the stress relief section 20 has a V-shape. The V-shape may have a corner 28 on the axis of symmetry S. For example, the nonlinear notch 23 and the interconnect trace 24 may have corners 28. The corner 28 may be sharp or rounded, etc. The corner 28 in the recessed portion 25 may be referred to as the inner corner 28a. Similarly, the corner 28 in the protruding portion 26 may be referred to as the outer corner 28b. Furthermore, the definitions of the stress relief section 20, the main section 21, and the pad mounting section 22 in the above embodiment apply. For example, the definition of the height b of the protruding portion 26 applies accordingly. Although in Figure 6 In the embodiment shown, the second external interconnect trace 24b forming the protrusion 26 has a sharp tip 27 or corner 28, but this tip 27 or corner 28 can be cut off or rounded. Therefore, the height b of the protrusion 26 can be reduced.

[0063] Figure 7 This is a public and Figure 6 The following is a top view of another embodiment similar to the one described above. In this embodiment, the stress relief section 20 has a W-shape. As described above, the W-shape can be formed by two V-shapes. In such an embodiment, the axis of symmetry S extends along the middle of the W-shape. The W-shape may have two protrusions 26 on the lower side of the W-shape. In some embodiments, the W-shape may have an additional protrusion 26 on the upper middle side of the W-shape. In such an embodiment, there may be a total of three protrusions 26. In some embodiments, the nonlinear cut 23 may not be continuous throughout the stress relief section 20, but may be discontinuous. In some embodiments, the nonlinear cut 23 may be continuous, or even a longer shape, for example, continuous throughout the entire W-shape.

[0064] Note that, for readability, some of the features indicated by the above-described markings have been omitted in other parts of the figures. However, it will be apparent to those skilled in the art that the cut-out corners can be applied to all other corners of this disclosure. Furthermore, it should be remembered that many other shapes can be used. For example, the stress-relieving section 20 is not limited to the... Figures 5 to 7 The shape described. For example, other shapes with an axis of symmetry, or even shapes without an axis of symmetry, can be used. For example, any concatenation of simple basic shapes or shapes disclosed herein is appropriate.

[0065] In Figures 5 to 7 When comparing the embodiments shown, the following differences become apparent. Figure 5 In the embodiment shown, the stress relief section 20, including the nonlinear notch 23 and / or interconnecting traces 24, has a rounded shape, while Figure 6 and Figure 7In the embodiment shown, the stress relief section 20 has a straight (or edged) shape. A rounded shape can distribute longitudinal stress in a more dispersed manner. Figure 7 and Figure 6 The straight (or edged) shape in the illustrated embodiment has linear portions and corner portions, which makes it easier to manufacture. (Comparison) Figure 6 and Figure 7 In the embodiment shown, the V-shape is more compact. On the other hand, the W-shape has the ability to allow the protruding portion 26 to move vertically in the middle. Therefore, the deformation characteristics of the stress relief section 20 can be adjusted. Furthermore, in all embodiments, the length of the nonlinear cut can be varied.

[0066] For all embodiments of this disclosure (including those described above), the conductor line may pass through the flexible interconnect 10 in the longitudinal direction. For example, the flexible interconnect 10 may include at least one conductor line. One conductor line connects a pad 40 (see example...) Figure 4 The flexible interconnect 10 is connected to the other end (where the BMU / BMS can be located). When the flexible interconnect 10 includes multiple conductor lines, the conductor lines can be distributed among the interconnect traces 24. For example, in each stress relief section 20, each interconnect trace 24 may include at least one conductor line. For example, one interconnect trace 24 may include multiple conductor lines. In such an embodiment, the distance between the conductor lines is taken into account when defining the width d of each interconnect trace 24. Similarly, when defining the width e of the nonlinear cutout 23, the degree of deformation of the interconnect traces 24 in the stress relief section 20 should be taken into account so that the interconnect traces 24 do not contact each other. In some embodiments, the interconnect traces 24 may contact each other, but the flexible interconnect 10 may be designed so that the conductor lines are not too close together, for example, do not contact each other. Furthermore, it will be clear to those skilled in the art that all measurements involved in this disclosure are taken in a relaxed state (i.e., a state without stress).

[0067] Some figure labels

[0068] 1 Battery Module

[0069] 2. Battery cell

[0070] 3 terminals

[0071] 10 Flexible Interconnection

[0072] 12 Flexible Printed Circuits

[0073] 17 mounting holes

[0074] 19 Pad Mounting Section

[0075] 20 Stress Relief Section

[0076] 21 Main Section

[0077] 22 Pad Mounting Section

[0078] 23 Non-linear cut

[0079] 24 Interconnection traces

[0080] 25. Depressed portion

[0081] 26. Protruding part

[0082] 27 Tips

[0083] 28. Corner

[0084] 28a Outer corner

[0085] 28b Inner corner

[0086] 30 busbars

[0087] 40 pads

Claims

1. A battery module, characterized by, Comprising: a plurality of battery cells stacked along a longitudinal direction; and a flexible interconnect configured to provide electrical information of the plurality of battery cells to a battery management unit, the flexible interconnect extending in the longitudinal direction and being fixed to the plurality of battery cells, the flexible interconnect comprising: a stress relief section extending in the longitudinal direction and comprising a plurality of interconnect traces, wherein the stress relief section has a cut-out extending along the longitudinal direction, the cut-out separating adjacent ones of the plurality of interconnect traces from each other, wherein the plurality of interconnect traces comprises a first peripheral interconnect trace forming a recessed portion and a second peripheral interconnect trace opposite to the first peripheral interconnect trace and forming a protruding portion, and wherein a height of the protruding portion in the stress relief section is equal to or smaller than a width of the flexible interconnect adjacent to the stress relief section. The stress relief section is flat.

2. The battery module of claim 1, wherein, The cut-out is non-linear.

3. The battery module of claim 2, wherein, The height of the protruding portion in the stress relief section is equal to or smaller than a width of one of the plurality of interconnect traces.

4. The battery module of claim 3, wherein, The width of the flexible interconnect adjacent to the stress relief section is equal to a width of the flexible interconnect in the stress relief section.

5. The battery module of claim 1, wherein, The flexible interconnect further comprises a pad mounting portion for mounting a pad, the pad being connected to one of the battery cells, 6. The battery module of claim 2, wherein, wherein the pad mounting portion is outside the stress relief section at an edge of the flexible interconnect extending in the longitudinal direction. The stress relief section is symmetrical about an axis perpendicular to the longitudinal direction and passing through a center of the stress relief section.

7. The battery module of claim 1, wherein, At least two of the plurality of interconnect traces have the same width.

8. The battery module of claim 1, wherein, The cut-out comprises a plurality of non-linear cut-outs, each of the non-linear cut-outs having the same width.

9. The battery module of claim 1, wherein, Each of the non-linear cut-outs has a meander shape, a wave shape, an omega shape, a V shape, or a w shape.

10. The battery module of claim 9, wherein, The flexible interconnect further comprises a conductor track.

11. The battery module of claim 1, wherein, The stress relief section further comprises a conductor track.

12. The battery module of claim 1, wherein, Each of the interconnect traces further comprises a conductor track.

13. The battery module of claim 1, wherein, The flexible interconnect is a flexible printed circuit.

14. The battery module of claim 1, wherein, A plurality of battery modules according to any one of claims 1 to 14.

15. A battery pack, characterized by A battery module according to any one of claims 1 to 14.

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