Multi-layer flexible battery interconnects and methods of making same

Abstract

The invention provides a multi-layer flexible cell interconnect for interconnecting cells in a battery pack and a method of manufacturing the same. A multi-layer flexible battery interconnect includes two insulating layers and two conductive layers stacked together and located between the insulating layers. One conductive layer is thicker than the other conductive layer. The thinner conductive layer includes a flexible tab for connection to the cell, and in some examples, a voltage sensing trace. The smaller thickness of these flexible webs ensures higher welding quality and allows less energy to be used during the welding process. It is ensured that the battery cell contacts to which the flexible tabs are welded can be significantly thicker. In addition, due to the small thickness, the fuse can be integrated into the flexible connecting piece. Meanwhile, the two conductive layers conduct current jointly in the interconnection piece, and the overall current-carrying capacity is enhanced through the thick layer. The two conductive layers may be soldered together to ensure electrical connection and mechanical support.

Description

[0001] This application is a divisional application of the invention patent application with application number 202280015555.6 and invention name “Multi-layer flexible battery interconnect and manufacturing method thereof”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application 63 / 237,333 (Case Number: CLNKP018P) filed on August 16, 2021 and U.S. Provisional Patent Application 63 / 165,582 (Case Number: CLNKP016P) filed on March 24, 2021 under 35 U.S.C. §119(e), and the entire contents of these U.S. Provisional Patent Applications are incorporated herein by reference for all purposes. Background Art

[0004] Rechargeable battery cells and battery packs assembled from these cells represent a promising technology for providing energy storage for mobile applications (e.g., electric vehicles) and stationary applications (e.g., power grids). In order to increase market penetration, the cost of battery cells and other battery pack components must be reduced. Although cells (e.g., lithium-ion cells and other types of cells) are currently the most expensive components in a battery pack, the cost of cells is expected to decrease in the future with economies of scale, new materials, and design improvements. In addition, the performance and life of battery cells should increase, leading to new high-durability applications. This trend will place greater emphasis on the cost, performance, and reliability of other components in the battery pack, especially battery interconnects. In addition, new and efficient methods for assembling battery packs using these components are also needed.

[0005] Many conventional battery packs are assembled using bulky metal plates with complex designs and functions. These metal plates interconnect the individual battery cells and transmit current between these cells and / or the battery pack terminals. Special fuses and / or connector wires are used to connect these plates to the battery cells, for example, to protect the individual cells from overcurrent and thermal runaway. These fuses can be brittle and can break under stress and vibration conditions, which can be common during operation of the battery pack. In addition, each plate is typically a stand-alone component, and large battery packs typically require multiple plates. This personalized assembly increases the cost and complexity of the battery pack and can adversely affect the safety and robust performance of the battery pack. Summary of the invention

[0006] A multilayer flexible battery interconnect and a method for manufacturing the same are provided for interconnecting batteries in a battery pack. The multilayer flexible battery interconnect includes an insulating layer and two conductive layers stacked together and located between the insulating layers. One conductive layer is thicker than the other conductive layer. The thinner conductive layer includes flexible tabs for connecting to the battery and, in some examples, voltage sensing traces. The smaller thickness of these flexible tabs ensures welding quality and allows less energy to be used during welding. The battery cell contacts on which these flexible tabs are welded can be significantly thicker. In addition, the smaller thickness enables fuses to be integrated into the flexible tabs. At the same time, the two conductive layers conduct current together within the interconnect, and the thicker layer enhances the overall current carrying capacity. The two conductive layers can be welded together to ensure electrical connection and mechanical support. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A is a schematic top view of a cylindrical battery cell illustrating center and edge contacts of the cell, according to some examples.

[0008] Figure 1B Based on some examples Figure 1A Schematic cross-sectional side view of a cylindrical battery cell in FIG.

[0009] Figure 1C is a schematic top view of a battery pack including a plurality of battery cells and interconnects according to some examples.

[0010] Figure 1D and Figure 1E is a schematic top view of a battery pack with additional interconnect examples.

[0011] Figure 2A are schematic perspective and partial cross-sectional views of a multi-layer flexible battery interconnect according to some examples.

[0012] Figure 2B yes Figure 2A Schematic perspective view of a portion of a multi-layer flexible battery interconnect in , focusing on the flexible tabs for connecting to the center contacts of a cell.

[0013] Figure 2C yes Figure 2A Schematic perspective view of a multi-layer flexible battery interconnect in which one insulating layer is removed to illustrate the different conductive layers of the interconnect.

[0014] Figure 2D yes Figure 2C Schematic perspective view of a portion of a multi-layer flexible battery interconnect in , focusing on the flexible tabs for connecting to the center contacts of a cell.

[0015] Figure 2Eis a schematic cross-sectional view of a portion of a multi-layer flexible battery showing a bus bar formed from two conductive layers and sealed between two insulating layers.

[0016] Figure 3 is a schematic top view of a multi-layer flexible battery interconnect identifying distances between different types of flexible tabs according to some examples.

[0017] FIG. 4A to FIG. 4D is a schematic side cross-sectional view of a battery pack according to some examples illustrating four battery cells interconnected by a multi-layer flexible battery interconnect.

[0018] Figure 5A is a schematic side cross-sectional view of a battery cell and a multi-layer flexible battery interconnect prior to making electrical connections to the cell, according to some examples.

[0019] Figure 5B yes Figure 5A Schematic top view of a multi-layer flexible battery interconnect in , showing an example of a center contact flexible tab.

[0020] Figure 5C and Figure 5D is a schematic side cross-sectional view of a battery cell and a multi-layer flexible battery interconnect after making electrical connections to the cell, according to some examples.

[0021] Figure 5E is a schematic top view of a multi-layer flexible battery interconnect showing an example of an edge contact flexible tab.

[0022] FIG. 6A to FIG. 6D is a schematic top view of voltage traces of a multi-layer flexible battery interconnect according to some examples.

[0023] Fig. 6E is a schematic side cross-sectional view of a battery cell and a multi-layer flexible battery interconnect including voltage traces according to some examples.

[0024] Fig. 6F is a schematic side cross-sectional view of a battery cell and a multi-layer flexible battery interconnect including signal traces and sensors connected to the signal traces according to some examples.

[0025] Fig. 7A is a schematic top view of four prismatic monomers illustrating the desired series connection of the monomers.

[0026] Figure 7B yes Fig. 7A Schematic top view of four prismatic cells in , illustrating a first conductive layer of a multi-layer flexible battery interconnect positioned above and interconnecting the cells.

[0027] Figure 7C yes Fig. 7A Schematic top view of four prismatic cells in FIG. 1 , illustrating first and second conductive layers of a multi-layer flexible battery interconnect positioned above and interconnecting the cells.

[0028] Fig.7D yes Fig. 7A Schematic top view of four prismatic monomers in , illustrating the entire interconnect located above them.

[0029] Figure 8 is a process flow diagram corresponding to a method of manufacturing a multi-layer flexible battery interconnect according to some examples.

[0030] Fig. 9 is a process flow diagram corresponding to another method for manufacturing a multi-layer flexible battery interconnect.

[0031] FIG. 10A to FIG. 10F Schematic diagram of the different parts and components used to make multi-layer flexible battery interconnects.

[0032] Fig.11A is a schematic cross-sectional view of a battery pack assembly including a battery and an interconnect circuit having a specially configured connection portion for connection with the battery, according to some examples.

[0033] Fig. 11B yes Fig.11A Schematic enlarged cross-sectional view of a portion of a battery pack assembly in FIG. 1 , illustrating an example of a connecting portion.

[0034] Fig. 11C yes Fig. 11B Schematic top view of a portion of a battery pack assembly.

[0035] Fig. 12A is a schematic top view of a portion of a battery pack assembly illustrating a tab opening in a conductor tab, according to some examples.

[0036] Fig. 12B yes Fig. 12A Schematic cross-sectional view of a portion of a battery pack assembly in FIG. 1 , illustrating a tab opening in a conductor tab according to some examples.

[0037] Fig.13A and Fig. 13B are schematic cross-sectional views of a battery pack assembly before and after electrical connections are made between conductor tabs of an interconnect circuit and a battery, according to some examples.

[0038] Fig. 13C and Fig.13Dis a schematic cross-sectional enlargement of two conductor necks showing different examples of partial openings in the conductor necks that provide flexibility to the conductor necks when making connection to a battery.

[0039] Fig.14A is a schematic top view of a conductor of an interconnect circuit used in a battery pack assembly showing a partial opening in the neck of the conductor that may serve as a fuse.

[0040] Fig. 14B yes Fig.14A Schematic cross-sectional view of a conductor in FIG. 1 , showing a partial opening in the conductor neck.

[0041] Fig. 14C yes Fig. 14B An enlarged schematic cross-sectional view of a conductor in FIG. 1 identifying various features of the partial opening in the neck of the conductor. DETAILED DESCRIPTION

[0042] When read in conjunction with the accompanying drawings, the subsequent detailed description of the examples of the present disclosure will be better understood. As used herein, an element or step listed in the singular and beginning with the word "one" should be understood to not exclude a plurality of said elements or steps, unless such exclusion is explicitly stated. In addition, reference to "an example" is not intended to be interpreted as excluding the existence of additional examples that also include the listed features. In addition, unless explicitly stated to the contrary, examples of "including" or "having" one or more elements with a particular characteristic may include additional elements that do not have that characteristic.

[0043] illustrate

[0044] Many modern battery packs include multiple cells that need to be interconnected. For example, a typical battery pack used in an electric vehicle has thousands of battery cells (e.g., cylindrical battery cells), or more specifically 18,650 cells, 21,700 cells, 4,680 cells, etc. The success of many battery applications often depends on robust, reliable, and inexpensive interconnects between battery cells in such a battery pack. As described above, some conventional interconnects use rigid metal plates (which may be referred to as bus bars) to connect to the cell contacts. Although these bus bars can transmit large currents and can provide some mechanical support, these bus bars are expensive to manufacture. For example, bus bar manufacturing requires unique tools (which may be expensive for each battery module. In addition, these bus bars are expensive and difficult to connect to the battery cell terminals. The rigidity of these bus bars may interfere with the relative movement of the battery cells and the plates, and may destroy the electrical connection between these components. Finally, the thickness of these bus bars also limits the thermal performance of the battery pack cooling plate / system, resulting in non-optimal unit energy (e.g., reducing the mileage in electric vehicle applications).

[0045] The multilayer flexible battery interconnect is specially configured to provide a reliable electrical connection, and in many cases, it may be easier to manufacture, connect to the cell terminals, and assemble into the battery pack than the conventional interconnect. The multilayer flexible battery interconnect also provides a current fusing function, which is further described below. Unlike the conventional printed circuit, which is generally limited to low current applications due to the small thickness of the conductive layer, the multilayer flexible battery interconnect can be configured to provide any current carrying capacity without affecting the ability to be welded to the battery contacts. For example, the thickness of the printed conductive element is limited by the mask and etching capabilities, which are generally not suitable for high aspect ratio features and thick conductors. In addition, the long etching required for thicker layers will increase the production cost of the flexible circuit. At the same time, many modern battery cells and battery packs are capable of operating at currents of at least 50A and even greater than 100A, such as during rapid charging or rapid discharge of the battery pack. This in turn requires the use of a thick conductive layer (e.g., a thickness of at least 200 microns and even at least 500 microns) to provide sufficient conductivity.

[0046] It should be noted that thick conductive layers present various challenges. First, thick conductive layers (e.g., having a thickness greater than 200 microns) are difficult to weld to battery cells or to attach to battery cells by other means. Thicker conductive layers require more energy to form welds, which dissipates more heat into the battery cells. At the same time, many monomer components (e.g., diaphragms, electrolytes) are heat sensitive and cannot withstand high temperatures (e.g., temperatures greater than 70°C). In addition, thick conductive layers present various challenges when fuses / fuse fuses are formed from these conductors. The fuse controls the electrical connection to the battery cell and disconnects the electrical connection to the battery cell when the current through the fuse exceeds a specific threshold controlled in part by the size of the fuse fuse. For example, etching thick conductors is difficult to achieve narrow traces with uniform widths. For etching, the minimum width to thickness ratio (referred to herein as "aspect ratio") is typically four or even five to avoid excessive undercutting associated with etching. For example, when etching a 200 micron thick conductor to form a fuse, the resulting width must be at least 700-800 microns, which may be too large for most battery cell fusing applications / types. In addition, since the back side must be protected from the etchant, it is generally not possible to form a fuse by etching that does not contact any other parts. Any physical contact with the fuse (other than with the rest of the conductor) is undesirable and it interferes with the thermal characteristics / overall performance of the fuse.

[0047] The multi-layer flexible battery interconnect described herein solves various defects of the above-mentioned conventional interconnects. In some examples, the multi-layer flexible battery interconnect includes two insulating layers (e.g., a first insulating layer and a second insulating layer) and two conductive layers (e.g., a first conductive layer and a second conductive layer). One conductive layer (e.g., the first conductive layer) is thicker than the other conductive layer (e.g., the second conductive layer). The two conductive layers form a stack that is at least partially insulated by the insulating layer and sealed between the insulating layers. The thinner conductive layer includes a flexible tab extending outside the stack or even outside the insulating layer. Specifically, the thinner second conductive layer has flexible tabs (of the same thickness) that allow electrical connections (e.g., welding) to the battery cell without requiring a lot of energy / heating the battery cell. The thinner conductive layer also ensures the quality of the laser welding. For example, the top cover thickness of a typical cylindrical battery cell is 0.3 mm or 0.4 mm. If the thickness of the conductive layer is the same as or thicker than the cover thickness, the welding performance will be affected. In this way, welding a thinner conductive layer to a thicker battery can provide a higher quality weld.

[0048] In addition, various fuses can be incorporated directly into the flexible tabs. The first conductive layer is thicker, which helps provide additional current carrying capacity through the interconnect. In some examples, the first conductive layer is at least twice as thick as the second conductive layer. In this way, the first conductive layer can be the main current carrier within the multi-layer flexible battery interconnect. The thickness of the first conductive layer can be adjusted to change these current carrying capacities of the multi-layer flexible battery interconnect without changing the thickness of the second conductive layer (and the thickness of the flexible tab).

[0049] For purposes of this disclosure, the term "interconnect" and "interconnect circuit" are used interchangeably, the term "conductive layer" and "conductor" or "conductor layer" are used interchangeably, and the term "insulating layer" and "insulator" are used interchangeably.

[0050] In some examples, a multi-layer flexible battery interconnect can be used to electrically interconnect a group of battery cells with terminals on the same side of the cells. These cells can be Figure 1A and Figure 1B Schematically shown cylindrical monomers (e.g., 18650 monomers, 21700 monomers, 4680 monomers, etc.) or Fig. 7A Specifically, Figure 1A is a schematic top view of a cylindrical battery cell 192 illustrating a first contact 194 (which may also be referred to as a center contact) and a second contact 195 (which may also be referred to as an edge contact), according to some examples. Figure 1B Based on some examples Figure 1A Schematic cross-sectional side view of a cylindrical battery cell 192 in FIG.

[0051] Figure 1C 1 is a schematic top view of a battery pack 190 according to some examples, the battery pack 190 including a plurality of battery cells 192 and a multi-layer flexible battery interconnect 100 forming a connection with each battery cell 192. The multi-layer flexible battery interconnect 100 is shown in the form of a circuit diagram to illustrate one example of connection in the battery pack 190. Specifically, in Figure 1C In this example, the multi-layer flexible battery interconnect 100 includes a first bus 101 and a second bus 102. Each bus is formed by two or more conductive layers described further below. One of the conductive layers (e.g., the thinner one) also forms a flexible tab 142 that is connected to the first contact 194 and the second contact 195 of the battery cell 192. The connection is formed by a contact pad 145 located at the end of the flexible tab 142. In this example, the first / center contact 194 of the left column battery cell 192 is connected to the flexible tab 142 of the first bus 101. The first / center contact 194 of the middle column battery cell 192 is also connected to the flexible tab 142 of the first bus 101. In this way, all cells 192 in the left column and the middle column are connected in parallel. The second / edge contact 195 of the middle column battery cell 192 is connected to the flexible tab 142 of the second bus 102. In this way, the first bus 101 and the second bus 102 are connected in series through the middle column battery cell 192. It should be noted that each flexible tab 142 of the second bus bar 102 is connected to two adjacent cells 192 of the middle column, or more specifically, to the second / edge contacts 195 of two adjacent cells 192 of the middle column. This double edge contact is possible because the second / edge contacts 195 of the two adjacent cells 192 are located adjacent to each other and can be achieved using the same contact pad 145. The connection to the first / center contact 194 is separate because these contacts are surrounded by the second / edge contacts 195 in this example. Finally, the second / edge contacts 195 of the right column of battery cells 192 are also connected to the flexible tab 142 of the second bus bar 102. In this way, all cells 192 of the right column and the center row are connected in parallel.

[0052] Figure 1D is a schematic top view of a battery pack 190 in which battery cells 192 are interconnected by another example of a multi-layer flexible battery interconnect 100. Figure 1C The difference lies in the position of the flexible tab 142 that forms the double edge contact. Figure 1C , forming the flexible tabs 142 that contact the double edges of the battery cells 192 of the left and right columns are aligned relative to each other along the X-axis. Now referring to Figure 1D, the flexible tabs 142 that form contact with the double edges of the battery cells 192 in the left and right columns are moved along the Y axis by one battery pitch. For the purpose of this disclosure, the term "battery pitch" is defined as the distance between the centers of two adjacent batteries in the same column. For cylindrical battery cells, the battery pitch is equal to the cell diameter plus the gap between two cells in the same column.

[0053] Figure 1E 1 is a schematic top view of a battery pack 190 in which battery cells 192 are interconnected by yet another example of a multi-layer flexible battery interconnect 100. Similarly, the connection scheme is similar to Figure 1C However, Figure 1E The multi-layer flexible battery interconnect 100 in FIG. 1 has more flexible tabs 142 to provide redundant edge contacts. Specifically, each battery cell 192 has two different flexible tabs 142 connected to its second / edge contact 195. This redundancy helps ensure that all cells remain connected without significant weight and cost disadvantages.

[0054] Examples of interconnect circuits and battery packs

[0055] Figure 2A is a schematic perspective view of a multi-layer flexible battery interconnect 100 for interconnecting battery cells 192 in a battery pack 190 according to some examples. Figure 2A , the multi-layer flexible battery interconnect 100 includes a first insulating layer 110, a second insulating layer 120, a first conductive layer 130, and a second conductive layer 140. The first conductive layer 130 is disposed between the first insulating layer 110 and the second insulating layer 120 and directly interfaces with the first insulating layer 110. The second conductive layer 140 is disposed between the first conductive layer 130 and the second insulating layer 120 and directly interfaces with each of the first conductive layer 130 and the second insulating layer 120. In addition, the first conductive layer 130 is thicker than the second conductive layer 140, i.e., T FCL >T SCL The first insulating layer 110, the first conductive layer 130 and most of the second conductive layer 140 are Figure 2A Not visible in the stereogram.

[0056] Reference Figure 2A In the perspective view in FIG. 1 , the second conductive layer 140 includes a flexible contact 142. The flexible contact 142 is used to electrically connect with the battery cell 192, for example, Figure 2B For example, Figure 2BTwo flexible tabs 142 are shown. The top tab is configured to connect to an edge contact of a battery cell 192 (schematically shown with dashed lines) and may be referred to as an edge contact flexible tab 149. The bottom tab is configured to connect to a center contact of a battery cell 192 and may be referred to as a center contact flexible tab 148. It should be noted that the two flexible tabs 142 (center contact flexible tab 148 and edge contact flexible tab 149) are part of different busses (and different parts of the second conductive layer 140).

[0057] The first conductive layer 130 is electrically connected to the second conductive layer 140, for example, by direct contact and / or welding. More specifically, the first conductive layer 130 and the second conductive layer 140 form a stack (eg, Figure 2A ), which may be referred to as a conductive stack. The second conductive layer 140 or more specifically the flexible tabs 142 of the second conductive layer 140 is responsible for connecting to the battery cell 192 and conducting current between the battery cell 192 and the conductive stack. However, within the conductive stack, the current is mainly carried by the thicker first conductive layer 130. In fact, the current carrying capacity is determined by the relative cross-sections of the first conductive layer 130 and the second conductive layer 140, and these cross-sections are proportional to the layer thickness.

[0058] In some examples, the first conductive layer 130 is at least twice as thick as the second conductive layer 140, or more specifically at least three times as thick. In the same or other examples, the thickness of the first conductive layer 130 is at least 300 microns or even at least 350 microns, while the thickness of the second conductive layer 140 is less than 200 microns or even less than 150 microns. For example, the thickness of the first conductive layer 130 is 400 microns, while the thickness of the second conductive layer 140 is 125 microns. As described above, the large thickness of the first conductive layer 130 allows a larger current, such as at least 50A and even greater than 100A, to be conducted through the multi-layer flexible battery interconnect 100. In addition, the large thickness of the first conductive layer 130 allows the use of less conductive materials, such as aluminum (compared to copper, copper is twice as conductive, but the price is significantly higher and the specific gravity is much higher). At the same time, the smaller thickness of the second conductive layer 140 allows the flexible tab 142 to be welded to the battery cell 192 without using a lot of energy (and therefore, without heating the battery cell 192).

[0059] In some examples, the first conductive layer 130 has a uniform thickness across the entire boundary of the first conductive layer 130. For example, the first conductive layer 130 can be formed from the same metal sheet. Different (unconnected) portions of the first conductive layer 130 (forming different busses of the same multi-layer flexible battery interconnect 100) can be formed from the same metal sheet. In the same or other examples, the second conductive layer 140 has a uniform thickness across the entire boundary of the second conductive layer 140.

[0060] In some examples, the first conductive layer 130 and the second conductive layer 140 are formed of the same material (e.g., aluminum). Since aluminum has a higher resistivity and a lower melting temperature relative to copper, using aluminum instead of copper may also help reduce the minimum achievable fusing current rating. In this way, forming a fuse in an aluminum conductive layer can allow more precise control of fusible parameters. Alternatively, the first conductive layer 130 and the second conductive layer 140 are formed of different materials. For example, the first conductive layer 130 is formed of aluminum, and the second conductive layer 140 is formed of copper. In general, the first conductive layer 130 and the second conductive layer 140 can be formed of any conductive material with sufficient conductivity (e.g., conductivity greater than 10^6 S / m or even greater than 10^7 S / m) to allow current to flow through the foil with low power loss.

[0061] In some examples, the first conductive layer 130 and the second conductive layer 140 may include a surface sublayer or coating for providing low electrical contact resistance and / or improving corrosion resistance. The surface sublayer may use techniques / materials including but not limited to brazing, laser welding, resistance welding, ultrasonic welding, bonding with a conductive adhesive, or mechanical pressure to help form electrical interconnects. The surface sublayer that can provide a suitable surface for these connection methods includes but is not limited to tin, lead, zinc, nickel, silver, palladium, platinum, gold, indium, tungsten, molybdenum, chromium, copper, their alloys, organic solderability preservatives (OSP) or other conductive materials. In addition, the surface sublayer may be sputtered, electroplated, cold welded or applied by other means. In some examples, the thickness of the surface sublayer may be in the range of 0.05 microns to 10 microns, or more specifically, in the range of 0.1 microns to 2.5 microns.

[0062] In addition, in some examples, adding an OSP coating on top of the surface sublayer can help prevent the surface sublayer itself from oxidizing over time. The surface sublayer can be used when the base sublayer of the first conductive layer 130 and the second conductive layer 140 includes aluminum or its alloy. If there is no protection, the exposed aluminum surface tends to form a natural oxide, which has insulating properties. Oxides are easily formed in the presence of oxygen or moisture. In order to provide a long-term stable surface in this case, the surface sublayer can resist the inward diffusion of oxygen and / or moisture. For example, zinc, silver, tin, copper, nickel, chromium or gold plating can be used as a surface layer on an aluminum-containing base layer.

[0063] Reference Figure 2A and Figure 2BIn some examples, the first conductive layer 130 and the second conductive layer 140 are welded together at a plurality of weld locations 109 that are separated from one another. For example, the weld locations 109 are formed by laser welding, but other forms of welding are also within the scope (e.g., ultrasonic welding, resistance welding). These weld locations 109 help conduct current between the first conductive layer 130 and the second conductive layer 140. In addition, these weld locations 109 help maintain the orientation of the first conductive layer 130 and the second conductive layer 140 and support the layers relative to each other. Additional support for the first conductive layer 130 and the second conductive layer 140 can be provided by the first insulating layer 110 and the second insulating layer 120, for example, the first insulating layer 110 and the second insulating layer 120 extend beyond the conductive stack and are directly laminated to each other, thereby forming a surrounding Figure 2E The encapsulated structure of the conductive stack shown and described below with reference to this figure.

[0064] It should be noted that the flexible tab 142 extends beyond the boundary of the conductive stack, or more specifically, beyond the boundary of the first conductive layer 130. The flexible tab 142 also extends beyond the boundary of the first insulating layer 110 and the second insulating layer 120 to form an electrical connection with the battery cell 192. More specifically, various openings are formed in the first insulating layer 110 and the second insulating layer 120 to allow the flexible tab 142 to pass through. These openings are aligned with the contacts of the battery cell 192, allowing the flexible tab 142 to protrude into the openings. More specifically, when connected to the battery cell 192, the flexible tab 142 protrudes into the opening formed in the first insulating layer 110 (facing the battery cell 192). When an electrical connection is formed between the flexible tab 142 and the battery cell 192, the opening in the second insulating layer 120 is used to pass the flexible tab 142.

[0065] In some examples, the openings in the first insulating layer 110 and the second insulating layer 120 are formed before laminating the insulating layers to the corresponding conductive layers, which is further described below. The openings can be formed using techniques including, but not limited to, punching, flat die cutting, matched metal die cutting, convex / concave die cutting, rotary die cutting, laser cutting, laser ablation, water jet cutting, machining, or etching.

[0066] The thickness of one or both of the first insulating layer 110 and the second insulating layer 120 can be between 1 micron and 500 microns, or more specifically, between 10 microns and 125 microns. In some examples, each of the first insulating layer 110 and the second insulating layer 120 includes an adhesive sublayer disposed on at least one surface facing the corresponding conductive layer, for example, for lamination to the conductive layer and to each other. These adhesive sublayers can also be used to directly laminate the first insulating layer 110 and the second insulating layer 120 (beyond the conductive layer boundary), as described below with reference to Figure 2EIn some examples, the surface of the first insulating layer 110 facing the battery cells 192 includes an adhesive sublayer for bonding to the battery cells 192 .

[0067] The first insulating layer 110 and the second insulating layer 120 provide electrical isolation and mechanical support to the first conductive layer 130 and the second conductive layer 140. In some examples, the first insulating layer 110 and the second insulating layer 120 may be initially processed in the form of a sheet or a roll, and then laminated to the conductive layer using, for example, an adhesive material. The first insulating layer 110 and the second insulating layer 120 may include (or be formed of) the following materials: polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), ethyl vinyl acetate (EVA), polyethylene (PE), polyvinyl fluoride (PVF), polyamide (PA), or polyvinyl butyral (PVB).

[0068] Reference Figure 2A and Figure 2B In some examples, the second insulating layer 120 includes welding openings 122. Each of the plurality of welding locations 109 is located within one welding opening 122. The welding openings 122 allow welding to be performed after the first conductive layer 130 and the second conductive layer 140 have been laminated between the first insulating layer 110 and the second insulating layer 120.

[0069] Reference Figure 2C and Figure 3 In some examples, the flexible tabs 142 include a first tab group 143 extending in a first direction (along the X-axis) and a second tab group 144 extending in a second direction opposite to the first direction. The first tab group 143 is used to form an electrical connection with the battery cells 192 located in one column, and the second tab group 144 is used to form an electrical connection with the battery cells 192 located in an adjacent column. It should be noted that the first tab group 143 and the second tab group 144 can be formed by any type of flexible tab 142. For example, Figure 2C The first and second contact groups 143, 144 for the center contact flexible contact 148 are identified, and Figure 3 Identified are a first contact group 143 and a second contact group 144 for edge contact flexible contacts 149. The first contact group 143 and the second contact group 144 are used to simply distinguish the locations of contacts on the same bus.

[0070] Figure 3 Different types of tabs and their relative positions within the multi-layer flexible battery interconnect 100 are shown. It should be noted that this tab arrangement corresponds to Figure 1C, and as described above. Specifically, the multi-layer flexible battery interconnect 100 includes a first bus 101 and a second bus 102. Each of the first bus 101 and the second bus 102 includes a first conductive layer 130 and a second conductive layer 140 (or is formed by the first conductive layer 130 and the second conductive layer 140), and the second conductive layer 140 includes a flexible tab 142. It should be noted that the conductive components of the first bus 101 and the second bus 102 are not directly connected to each other. However, these conductive components can be interconnected through the battery cell 192. The first bus 101 and the second bus 102 share a first insulating layer 110 and a second insulating layer 120, and the first insulating layer 110 and the second insulating layer 120 can be used for mechanical support of the first bus 101 and the second bus 102 relative to each other.

[0071] Reference Figure 3 , the first bus bar 101 and the second bus bar 102 have different types of flexible tabs 142. Specifically, the flexible tabs 142 of the second conductive layer 140 forming the first bus bar 101 are configured to connect to the first / center contact 194 of the battery cell 192 and are referred to as center contact flexible tabs 148. On the other hand, the flexible tabs 142 of the second conductive layer 140 forming the second bus bar 102 are configured to connect to the second / edge contact 195 of the battery cell 192 and are referred to as edge contact flexible tabs 149. In some examples, each edge contact flexible tab 149 is configured to connect to the edge contacts 195 of two adjacent battery cells 192.

[0072] like Figure 3 As shown, one edge contact flexible tab 149 and one center contact flexible tab 148 are connected to each battery cell 192. Figure 1D In some examples described, two edge contact flexible tabs 149 and one center contact flexible tab 148 are connected to each battery cell 192. In either case, the edge contact flexible tabs 149 and the center contact flexible tabs 148 extend over the same column of battery cells 192 to form an interdigitated assembly. It should be noted that the edge contact flexible tabs 149 and the center contact flexible tabs 148 both have a first tab group 143 and a second tab group 144 extending in different directions.

[0073] Figure 3 1 and 2 show various spacings between flexible tabs 142 (in the same or different groups and / or in the same or different buses). In some examples, the first tab group 143 is offset relative to the second tab group 144 by half of the cell pitch of the battery pack 190. This offset applies to the center contact flexible tab 148 and the edge contact flexible tab 149.

[0074] Reference Figure 3In some examples, any two adjacent tabs in the first tab group 143 are spaced apart by the cell pitch of the battery pack 190. Any two adjacent tabs in the second tab group 144 are also spaced apart by the cell pitch of the battery pack 190.

[0075] Reference Figure 3 In some examples, any two adjacent edge-contacting flexible tabs 149 are spaced apart by the cell pitch of the battery pack 190 or twice the cell pitch. More specifically, any two adjacent tabs in the first tab group 143 are spaced apart by the cell pitch of the battery pack 190 or twice the cell pitch. Similarly, any two adjacent tabs in the second tab group 144 are spaced apart by the cell pitch of the battery pack 190 or twice the cell pitch.

[0076] Figure 2B A center contact flexible tab 148 is shown, which includes a contact pad 145 and a fuse 146, which connects the contact pad 145 and supports the contact pad 145 relative to the rest of the second conductive layer 140. The contact pad 145 is configured to connect to the center contact 195 of one battery 192. In addition, the second insulating layer 120 includes a contact opening 123, so that the fuse 146 and at least a majority of the contact pad 145 protrude into the contact opening 123. Therefore, the fuse 146 is not affected by the thermal mass of the second insulating layer 120 (although the fuse 146 can be at least partially supported by the first insulating layer 110). In addition, when the contact pad 145 is welded to the first / center contact 194 of the battery cell 192, the contact opening 123 provides a path for the contact pad 145.

[0077] Reference Figure 2B as well as Figure 5A , Figure 5B and Figure 5E In some examples, the second insulating layer 120 includes a support tab 124 that at least partially defines the contact opening 123. A portion of the contact pad 145 is adhered to the support tab 124. The support tab 124 supports the contact pad 145 at least before the electrical connection with the battery cell 192 is formed. In some examples, the contact pad 145 is separated from the support tab 124 when the electrical connection is formed. Alternatively, the contact pad 145 remains adhered to the support tab 124 even after the electrical connection is formed, for example, Figure 5C In another example, the support tab 124 is separated from the rest of the second insulating layer 120 while forming the electrical connection, for example, Figure 5D As shown schematically in FIG.

[0078] Reference Figure 2B as well as Figure 5A , Figure 5B and Figure 5E In some examples, the second insulating layer 120 includes a flexible slit 125 extending along an interface between the support tab 124 and the remainder of the second insulating layer 120. For example, when the contact pad 145 faces a battery cell and forms an electrical connection with the cell, the flexible slit 125 facilitates out-of-plane bending (XY plane) of the support tab 124.

[0079] Reference Figure 5A and Figure 5B In some examples, at least a portion of the fuse 146 is adhered to the first insulating layer 110. For example, the first insulating layer 110 includes a fuse support tab 114 extending beyond the edge formed by the first insulating layer 110 and the second insulating layer 120. It should be noted that although one surface of the fuse 146 is adhered to the first insulating layer 110, the other surface of the fuse 146 is exposed, thereby reducing the influence of the insulating layer on the performance of the fuse 146.

[0080] Reference Figure 2B and Figure 5E In some examples, the edge contact flexible tab 149 includes a contact pad 145 and a flexible neck 147. The flexible neck 147 connects the contact pads 145 and supports the contact pads 145 relative to the rest of the edge contact flexible tab 149. Unlike the fuse 146, the flexible neck 147 is much wider and does not provide a current control function. However, when the contact pads 145 of the edge contact flexible tab 149 are connected to their corresponding edge contacts 195, the flexible neck 147 is able to support current from two battery cells 192. In general, in some examples, the contact pads 145 are configured to simultaneously connect to the edge contacts 195 of two adjacent batteries in the battery 192. These connections are in Figure 5E The welding area is schematically shown in FIG.

[0081] Reference Figure 5E In some examples, the second insulating layer 120 includes a contact opening 123. The flexible neck 147 and a majority of the contact pad 145 protrude into the contact opening 123. The contact opening 123 allows for out-of-plane bending (XY plane) of the contact pad 145 when the edge contact flexible tab 149 forms a connection with the battery cell 192. In addition, the contact opening 123 allows access to the contact pad 145 while forming these connections.

[0082] Reference Figure 2EIn some examples, the first insulating layer 110 and the second insulating layer 120 are directly adhered to each other, forming a boundary around a portion of the first conductive layer 130 and a portion of the second conductive layer 140. This feature helps maintain the orientation of the first conductive layer 130 and the second conductive layer 140 before they are welded together. In addition, this feature isolates the conductive layer portions from the environment, for example, to prevent electrical shorts and / or corrosion.

[0083] In some examples, the thicker conductive layer is located between the battery cell and the thinner conductive layer, thereby providing access to the thinner conductive layer (ie, from the opposite side of the battery cell). Figure 4A and Figure 4B , the first conductive layer 130 is thicker than the second conductive layer 140. The second conductive layer 140 can be accessed through the welding opening 122 in the second insulating layer 120, for example, to weld the second conductive layer 140 to the first conductive layer 130 and form the welding location 109. In some examples, the welding is performed at the same time as the flexible tab 142 is welded to the battery cell 192. Specifically, Figure 4A Edge contact flexible tabs 149 are shown, each edge contact flexible tab 149 being connected to two adjacent battery cells 192 . Figure 4B Center contact flexible tabs 148 are shown, each connected to one or more battery cells 192 .

[0084] In some examples, the thinner conductive layer is positioned between the battery cell and the thicker conductive layer, thereby positioning the flexible tab (which is part of the thinner conductive layer) closer to the battery cell. In other words, the flexible tab needs to have less out-of-plane bending to reach the battery cell. Figure 4C and Figure 4D , the first conductive layer 130 is thinner than the second conductive layer 140. In this example, the flexible tab 142 is a part of the first conductive layer 130. Figure 4C Edge contact flexible tabs 149 are shown, each of which connects two adjacent battery cells 192 . Figure 4D Center contact flexible tabs 148 are shown, each of which is connected to one or more battery cells 192 .

[0085] As described above, the flexible tab 142 is positioned in a plane with the rest of the conductive layer prior to making electrical connections to the battery cells. Figure 5A is a schematic side cross-sectional view of a battery cell 192 and multi-layer flexible battery interconnect 100 prior to making an electrical connection to the battery cell 192. In this example, a connection to the center contact 195 of the battery cell 192 is to be made. Figure 5B yes Figure 5ASchematic top view of a multi-layer flexible battery interconnect 100 in FIG. A flexible tab 142 (which in this example may be referred to as a center contact flexible tab 148) is supported by a support tab 124. More specifically, a portion of a contact pad 145 of the flexible tab 142 is adhered to the support tab 124.

[0086] Figure 5C and Figure 5D 1 is a schematic side cross-sectional view of a battery cell 192 and a multi-layer flexible battery interconnect 100 after an electrical connection is made to a battery cell 192. Specifically, the contact pad 145 is bent out of plane and protrudes into an opening in the first insulating layer 110. During this operation, another opening in the second insulating layer 120 provides access for the contact pad 145. The contact pad 145 is in direct contact with the center contact 195 of the battery cell 192 and is welded to the center contact 195 at this location. The support tab 124 may remain attached to the contact pad 145. In some examples, such as Figure 5D As shown, the support tab 124 is separated from the rest of the second insulating layer 120 .

[0087] Voltage Trace Example

[0088] FIG. 6A to FIG. 6D 1 is a schematic top view of a voltage trace 150 of a multi-layer flexible battery interconnect 100 according to some examples. For example, the voltage trace 150 can be used to monitor the voltage at each bus bar of the multi-layer flexible battery interconnect 100. In other words, each voltage trace 150 is connected to a different bus bar and is used to monitor the voltage at the bus bar. Specifically, Fig. 6A The voltage traces 150 are illustrated as being part of the second conductive layer 140. More specifically, each voltage trace 150 is integral with a corresponding portion of the second conductive layer 140 to form the same bus bar.

[0089] In some examples, the voltage trace 150 (or other components of the second conductive layer 140) are formed of a material that may not be suitable for some applications (e.g., forming a connection with a connector terminal). For example, the voltage trace 150 is formed of aluminum that is not easily brazed. In these examples, the multi-layer flexible battery interconnect 100 includes a transition trace 152, such as FIG. 6B to FIG. 6D As shown. The transition trace 152 can be formed of a different material (e.g., copper) than the voltage trace 150 (e.g., aluminum). Each voltage trace 150 can have a corresponding transition trace 152. However, the number of voltage traces 150 and transition traces 152 can be different in some examples (e.g., unused traces, multiple transition traces 152 connected to one voltage trace 150, etc.). The transition trace 152 can overlap with the voltage trace 150 and can be welded to the voltage trace 150 (e.g., in the same manner as the second conductive layer 140 is welded to the first conductive layer 130). The connection portion 151 is FIG. 6B to FIG. 6D The transition trace 152 may then be connected to a terminal 155 of a connector 154 .

[0090] Reference Figure 6C and Fig.6D In some examples, a variety of options for interconnecting the transition traces 152 and the voltage traces 150 are available. For example, the insulating layer 156 is located between the transition traces 152 and the voltage traces 150. In some examples, the insulating layer 156 can be one of the first insulating layer 110 or the second insulating layer 120. In addition, the transition traces 152 and the voltage traces 150 can overlap to form a many-to-many grid, such as Figure 6C and Fig.6D In other words, each transition trace 152 overlaps with a plurality of voltage traces 150. Moreover, each voltage trace 150 overlaps with a plurality of transition traces 152. For example, Figure 6C and Fig.6D The transition traces 152 and the voltage traces 150 are illustrated extending at right angles relative to each other such that each transition trace 152 overlaps all of the voltage traces 150 .

[0091] This insulation, overlap, and orientation of transition traces 152 and voltage traces 150 allows for different connection options. Figure 6C , the left transition trace 152 is connected to the top voltage trace 150, the middle transition trace 152 is connected to the middle voltage trace 150, and the right transition trace 152 is connected to the bottom voltage trace 150. Fig.6D , the left transition trace 152 is connected to the bottom voltage trace 150, the middle transition trace 152 is connected to the top voltage trace 150, and the right transition trace 152 is connected to the middle voltage trace 150. It should be noted that one transition trace 152 can be connected to multiple voltage traces 150. Similarly, multiple transition traces 152 can be connected to the same voltage trace 150. One of ordinary skill in the art will recognize the various overlap and connection options.

[0092] Fig. 6E 1 is a schematic side cross-sectional view of a battery cell 192 and a multi-layer flexible battery interconnect 100 including a voltage trace 150 according to some examples. Here, the voltage trace 150 is positioned as a separate layer (separate from other conductive layers) in the multi-layer flexible battery interconnect 100, such as stacked with other components. For example, the second insulating layer 120 is located between at least a portion of the voltage trace 150 and the second conductive layer 140. The second insulating layer 120 includes an opening through which the voltage trace 150 can be connected to one of the bus bars formed by the conductive layer. Fig. 6EAlso illustrated is a third insulating layer 160 which isolates the voltage trace 150 from the environment and also supports the voltage trace 150 relative to the second insulating layer 120 .

[0093] Fig. 6F 1 is a schematic side cross-sectional view of a battery cell 192 and a multi-layer flexible battery interconnect 100 including a signal trace 158 and a sensor 159 connected to the signal trace 158 according to some examples. Various examples of sensor 159 are within the scope, such as thermocouples, humidity sensors, pressure sensors, etc. In some examples, sensor 159 is connected to a conductive layer (e.g., such as Fig. 6F The second conductive layer 140 is shown directly connected to the substrate.

[0094] Example of interconnected prismatic monomers

[0095] Although the above examples of multi-layer flexible battery interconnect 100 are described in the context of cylindrical battery cells, many of the features described are also applicable to prismatic battery cells. Fig. 7A 1 is a schematic top view of four prismatic battery cells 192, illustrating the desired series connection of these cells. Specifically, each battery cell 192 includes a first contact 194 and a second contact 195. Although Fig. 7A Alternating flipped positions of prismatic battery cells 192 and series connection of these cells are illustrated, but various other orientations and connections are within the scope.

[0096] Figure 7B yes Fig. 7A 192, illustrating a second conductive layer 140 of the multi-layer flexible battery interconnect 100 positioned above and interconnecting the cells 192. The second conductive layer 140 is shown separately to illustrate various features of the layer. One of ordinary skill in the art will recognize that the second conductive layer 140 is part of the multi-layer flexible battery interconnect 100, which includes other components, such as the first conductive layer 130, the first insulating layer 110, and the second insulating layer 120. The second insulating layer 120 is not shown. One of ordinary skill in the art will also recognize that the second insulating layer 120 is located between the prismatic battery cells 192 and the second conductive layer 140, and includes openings aligned with the first contact 194 and the second contact 195 of each cell.

[0097] Figure 7C yes Fig. 7ASchematic top view of four prismatic cells 192 in the multi-layer flexible battery interconnect 100, illustrating that the first conductive layer 130 and the second conductive layer 140 are positioned above the cells and interconnect the cells. The first conductive layer 130 is thicker than the second conductive layer 140. In this way, only the second conductive layer 140 is directly welded to the first contact 194 and the second contact 195 of the cell. In addition, the occupied area of ​​the first conductive layer 130 is smaller than the occupied area of ​​the second conductive layer 140. The second conductive layer 140 extends beyond the first conductive layer 130, especially above the battery contacts. This feature allows the second conductive layer 140 to be welded to these battery contacts without interference from the first conductive layer 130. The second conductive layer 140 is a thinner layer and requires less welding energy, thereby avoiding excessive temperatures at the battery contacts. At the same time, the first conductive layer 130 provides additional conductivity between the battery contacts without being directly connected to these contacts.

[0098] Fig.7D yes Fig. 7A Schematic top view of four prismatic cells 192 in FIG. 1 , which illustrates the entire multi-layer flexible battery interconnect 100 located above the battery cells. Specifically, Fig.7D Various openings in the first insulating layer 110 are shown. These openings are used to form various connections. Internal welding openings 118 are located above both the first conductive layer 130 and the second conductive layer 140 and are used to weld the two conductive layers together. External welding openings 119 are located above the second conductive layer 140 (but not above the first conductive layer 130) and are used to weld the second conductive layer 140 to the battery contacts.

[0099] Example of making multi-layer flexible battery interconnects

[0100] Figure 8 is a process flow diagram corresponding to a method 800 of manufacturing a multi-layer flexible battery interconnect 100 according to some examples. Various examples of a multi-layer flexible battery interconnect 100 are described above.

[0101] In some examples, the method 800 includes patterning the first insulating layer 110 (block 810). An example of the first insulating layer 110 is Fig. 10A For example, various openings 117 may be formed in a continuous base film to create a first insulating layer 110. These openings 117 provide access for flexible tabs 142 within the multi-layer flexible battery interconnect 100.

[0102] Return to Figure 8 In some examples, the method 800 includes patterning the first conductive layer 130 (block 812). An example of the first conductive layer 130 is Fig. 10BFor example, individual portions of the first conductive layer 130 may be formed from a continuous base metal foil, thereby producing the first conductive layer 130. Each of these portions represents a different bus (e.g., Fig. 10B Three different portions are shown). In some examples, at least before first conductive layer 130 is laminated to first insulating layer 110, first conductive layer 130 is supported on a temporary substrate (e.g., also used for patterning of first conductive layer 130). Once first conductive layer 130 is first insulating layer 110, first insulating layer 110 provides support for unconnected portions of first conductive layer 130.

[0103] Return to Figure 8 In some examples, method 800 includes laminating (block 814) first conductive layer 130 to first insulating layer 110. For example, first insulating layer 110 may include an adhesive surface to which first conductive layer 130 is adhered. An example of a subassembly including first conductive layer 130 and first insulating layer 110 is shown in FIG. Fig. 10C As described above, the first insulating layer 110 provides support for the unconnected portion of the first conductive layer 130 .

[0104] Return to Figure 8 In some examples, the method 800 includes patterning the second insulating layer 120 (block 820). An example of the second insulating layer 120 is Fig. 10D For example, various openings may be formed in a continuous base film to create a second insulating layer 120. Some openings 127 provide access to flexible tabs 142 within the multi-layer flexible battery interconnect 100. Other openings are welding openings 122 and are used to weld the first conductive layer 130 to the second conductive layer 140, as described above.

[0105] Return to Figure 8 In some examples, the method 800 includes patterning the second conductive layer 140 (block 822). An example of the second conductive layer 140 is Fig. 10E . For example, separate portions of the second conductive layer 140 can be formed from a continuous base metal foil, thereby producing the second conductive layer 140. Each of these portions represents a different bus of the multi-layer flexible battery interconnect 100. In addition, each portion includes a flexible tab 142 for making electrical connections to a battery cell. In some examples, at least before the second conductive layer 140 is laminated to the second insulating layer 120, the second conductive layer 140 is supported on a temporary substrate (e.g., also used for patterning).

[0106] Return to Figure 8In some examples, the method 800 includes laminating (block 824) the second conductive layer 140 to the second insulating layer 120. For example, the second insulating layer 120 may include an adhesive surface to which the second conductive layer 140 is adhered. An example of a subassembly including the second conductive layer 140 and the second insulating layer 120 is shown in FIG. Fig.10F After this lamination operation, the second conductive layer 140 supports the unconnected portion of the second conductive layer 140 .

[0107] return Figure 8 In some examples, method 800 includes laminating (block 830) a stack including first conductive layer 130 and second conductive layer 140. First conductive layer 130 may be pre-laminated to first insulating layer 110, and second conductive layer 140 may be pre-laminated to second insulating layer 120. Thus, first insulating layer 110 and second insulating layer 120 are also part of the laminated stack. For example, portions of first insulating layer 110 and second insulating layer 120 that extend beyond first conductive layer 130 and second conductive layer 140 may be adhered together during this operation, such as Figure 2E The combination of the first insulating layer 110, the first conductive layer 130, the second conductive layer 140, and the second insulating layer 120 may be referred to as a main stack.

[0108] Return to Figure 8 In some examples, method 800 includes welding (block 832) the first conductive layer 130 and the second conductive layer 140. As described above with reference to Figure 2A and Figure 2B As described, the second insulating layer 120 includes a plurality of welding openings 122 for accessing the second conductive layer 140 and welding the second conductive layer 140 to the first conductive layer 130, thereby forming welding locations 109. For example, laser welding may be used for this purpose.

[0109] When the multi-layer flexible battery interconnect 100 includes voltage traces or signal traces provided as separate layers, such as Fig. 6E and Fig. 6F As schematically shown in FIG. 8 , the method 800 may include patterning the third insulating layer 160 (block 840), patterning the voltage trace 150 (block 842), and laminating the voltage trace 150 (block 844) to the third insulating layer 160 to form an additional stack. The method 800 then continues by laminating the additional stack to the main stack (block 850), and in some examples, soldering the voltage trace 150 to a conductive layer, such as the second conductive layer 140, which may be thinner and may be located on top of the first conductive layer 130 and closer to the voltage trace 150.

[0110] Fig. 9is a process flow diagram corresponding to another method 900 for manufacturing a multi-layer flexible battery interconnect 100. Some operations of method 900 may be similar to corresponding operations of method 800 described above. In some examples, method 900 includes patterning first insulating layer 110 (block 910), which is similar to the operations described above represented by block 810. Method 900 includes patterning first conductive layer 130 (block 912), which is similar to the operations described above represented by block 812. Method 900 continues by laminating (block 914) first insulating layer 110 to first conductive layer 130, which is similar to the operations described above represented by block 814. In addition, method 900 continues by patterning second conductive layer 140 (block 920), which is similar to the operations described above represented by block 822. Method 900 then continues by laminating (block 923) a stack including first insulating layer 110, first conductive layer 130, and second conductive layer 140. It should be noted that the second insulating layer 120 is not part of the stack. The second insulating layer 120 is subsequently added. When the second conductive layer 140 can be supported relative to the first insulating layer 110 and the first conductive layer 130 using a portion of the second conductive layer 140 that extends beyond the boundary of the first conductive layer 130 and adheres to the first insulating layer 110 (e.g., a portion of the flexible tab 142 that overlaps the first insulating layer 110). The method 900 includes patterning the second insulating layer 120 (block 930) (similar to the operations described above represented by block 820), then laminating the second insulating layer 120 (block 934) to the stack including the first insulating layer 110, the first conductive layer 130, and the second conductive layer 140, and welding (block 940) the first conductive layer 130 and the second conductive layer 140.

[0111] Example of battery pack connection

[0112] Fig.11A is a schematic diagram of a battery pack assembly 1100 according to some examples. The battery pack assembly 1100 includes an interconnect circuit 1110 and a battery 1150. Although Fig.11AOnly one battery 1150 is illustrated, but one of ordinary skill in the art will appreciate that the same interconnect circuit 1110 can be used to connect multiple batteries, for example, to interconnect the batteries and / or to other components of the battery pack assembly 1100 (e.g., an inverter). The interconnect circuit 1110 includes a conductor 1120 and a first insulating layer 1111. The conductor 1120 may also be referred to as a conductive element. In some examples, the first insulating layer 1111 provides support for the conductor 1120. For example, the interconnect circuit 1110 may include multiple conductors, and the first insulating layer 1111 supports the conductors relative to each other (e.g., to prevent short circuits and guide the conductors to a desired location). The first insulating layer 1111 may also be used to insulate the conductor 1120 from other components (e.g., the battery 1150). In some examples, the interconnect circuit 1110 includes a second insulating layer 1112, such that at least a portion of the conductor 1120 is located between the first insulating layer 1111 and the second insulating layer 1112. The insulating layer may also be referred to as a dielectric layer or simply a dielectric body. Various examples of dielectric bodies and conductive elements are described above.

[0113] In some examples, the first insulating layer 1111 includes a first insulating layer opening 1113, which is used to allow a portion of the conductor 1120 to protrude, for example, when connected to the battery 1150. Similarly, the second insulating layer 1112 can include a second insulating layer opening 1114, which is used to allow, for example, the conductor 1120 to pass through. For example, the second insulating layer opening 1114 can be used to allow a portion of the conductor 1120 to pass through and force the portion through the first insulating layer opening 1113, for example, to form an electrical contact with the battery 1150.

[0114] In some examples, the conductor 1120 includes a conductor trace 1128, a conductor neck 1126, and a conductor tab 1122, such that the conductor neck 1126 is located between and connects the conductor trace 1128 and the conductor tab 1122. The conductor trace 1128 extends away from the first insulating layer opening 1113 and is used to form other electrical connections with the conductor 1120. The conductor tab 1122 is mechanically and electrically connected (e.g., welded) to the battery 1150, as further described below. The conductor neck 1126 provides flexibility to the conductor tab 1122, for example, allowing the conductor tab 1122 to be positioned out of plane relative to the conductor trace 1128. For example, Fig.11A The conductor tab 1122 is illustrated extending beyond the opposite side of the first insulating layer 1111 relative to the conductor trace 1128. In this example, the conductor neck 1126 protrudes through the first insulating layer opening 1113. In addition, in some examples, the conductor neck 1126 allows the battery 1150 to move relative to the rest of the interconnect circuit 1110 (e.g., to a certain extent) without disrupting the connection between the conductor tab 1122 and the battery 1150.

[0115] In some examples, the battery 1150 includes a battery housing 1154, a battery cap 1152, and a battery cap insulator 1156. A person of ordinary skill in the art will appreciate that the battery 1150 includes Fig.11A 1154 and the like. The battery cap insulator 1156 supports the battery cap 1152 relative to the battery housing 1154 and also insulates the battery cap 1152 from the battery housing 1154. In some examples, the battery housing 1154 can operate as one terminal of the battery 1150, while the battery cap 1152 can operate as the other terminal. Although Fig.11A The conductor 1120 is illustrated as being connected to the battery cap 1152, but one of ordinary skill in the art will appreciate that in other examples, the conductor 1120 may be connected to the battery housing 1154, such as a shoulder of the battery housing 1154 that surrounds the battery cap 1152 and extends above the battery cap insulator 1156.

[0116] In some examples, the conductor contact 1122 includes a connecting portion 1124, and the thickness of the connecting portion 1124 is less than the thickness of the remaining portion of the conductor contact 1122, such as Fig.11A and Fig. 11B In other examples, the conductor tab 1122 includes one or more tab openings 1130, such as Fig. 12A and Fig. 12B The conductor tab 1122 is welded to the battery 1150 at the connection portion 1124 or around one or more tab openings 1130. Each of these examples will now be described in more detail.

[0117] As mentioned above, Fig.11A and Fig. 11BAn example of a battery pack assembly 1100 is illustrated in which a conductor tab 1122 includes a connecting portion 1124 having a thickness that is less than the thickness of the remainder of the conductor tab 1122. For example, the conductor 1120 is formed from the same metal sheet, in which case all components of the conductor 1120 (e.g., the conductor trace 1128, the conductor neck 1126, and the conductor tab 1122) have the same thickness. As such, the thickness of the conductor tab 1122 may be selected for reasons associated with other components of the conductor 1120 (e.g., the current carrying properties of the conductor trace 1128). In some examples, the primary thickness of the conductor 1120 is at least 100 microns or even at least 200 microns. Welding such a thick sheet to the battery 1150 requires significant heating of the conductor 1120 and the battery 1150, which may be undesirable, at least from the battery's perspective. For example, the battery 1150 includes various components (e.g., insulators, separators, electrolytes) that may be sensitive to high temperatures. Using a much smaller thickness of the connecting portion 1124 to form an electrical connection with the battery 1150 allows for significantly reduced high temperature exposure when welding the connecting portion 1124 to the battery 1150 .

[0118] In some examples, the thickness of the connecting portion 1124 is at least one-half, one-third, or even one-quarter of the thickness of the rest of the conductor tab 1122. In some examples, the connecting portion 1124 is circular, for example, Fig. 11C As shown. For example, the shape (and size) of the connecting portion 1124 can be the same as the battery component to which the connecting portion 1124 is welded. For example, the connecting portion 1124 welded to the battery cap 1152 may have a circular footprint. In some examples, the connecting portion 1124 is smaller than the area of ​​the battery component to which the connecting portion 1124 is welded. More specifically, the size of the connecting portion 1124 can be determined by the welding requirements (e.g., the weld nugget size). In the same or other examples, the remainder of the conductor tab 1122 forms an edge shoulder 1123 surrounding the connecting portion 1124. It should be noted that the thickness of the edge shoulder 1123 is the same as the main thickness of the conductor 1120 and is greater than the thickness of the connecting portion 1124.

[0119] As mentioned above, Fig. 12A and Fig. 12B An example of a battery pack assembly 1100 is illustrated in which a conductor tab 1122 includes one or more tab openings 1130. Similar to the connection portion 1124 described above, the tab openings 1130 allow for a reduction in the power required to weld the conductor tab 1122 to the battery 1150. For example, the tab openings 1130 include sidewalls that increase the surface area of ​​the conductor tab 1122 for welding.

[0120] In some examples, each of the one or more tab openings 1130 has an elongated shape, such as Fig. 12A More specifically, the elongated shape extends perpendicular to the conductor neck 1126 or more specifically perpendicular to the central axis of the conductor neck 1126. Fig. 12A As shown, the conductor neck 1126 extends along the X-axis, while the elongated shape of the tab opening 1130 extends along the Y-axis.

[0121] Reference Fig. 12B In some examples, the conductor tab 1122 also includes a weld nugget 1134 disposed within each of the one or more tab openings 1130 and directly interfacing with the battery 1150. The weld nugget 1134 increases the interface area between the conductor tab 1122 and the battery 1150 by utilizing more of the sidewalls 1133 of the tab opening 1130. In some examples, the conductor tab 1122 is welded to the battery 1150 using a resistance welder, a laser welder, and / or an ultrasonic welder. However, other forms of attachment (e.g., conductive adhesives) are also within the scope.

[0122] Reference Fig.13A In some examples, the interconnect circuit 1110 is provided as a substantially planar structure positioned above the battery 1150. More specifically, before forming a connection with the battery 1150, the conductor tab 1122 of each conductor 1120 is substantially coplanar with other components of the conductor 1120 such as the conductor trace 1128 and the conductor neck 1126 (and other conductors). To form a connection with the battery 1150, each conductor neck 1126 is bent so that the conductor tab 1122 protrudes through the first insulating layer 1111 and reaches the battery 1150. For example, as Fig.13A The pressure clamp shown can be used for this purpose. It should be noted that this conductor neck bending operation can be performed on dozens or even hundreds of such conductor necks simultaneously, for example, using the same interconnect circuit 1110 to connect to multiple cells in the same battery pack. In addition, the thickness of the conductor neck 1126 (e.g., greater than 100 microns or even greater than 200 microns) can be an important factor in determining the force required to simultaneously bend such multiple conductor necks to form a connection with the battery. Finally, the material used for conductor 1120 (e.g., aluminum) can have a significant flexural modulus, resulting in a high resistance to bending. All of these factors indicate that significant force is required to bend the conductor neck 1126 when forming a connection with the battery 1150, which can be a problem in the battery pack. Fig. 13B The large forces require heavy equipment and may damage certain parts of the overall assembly (eg, especially if there is some misalignment).

[0123] For example, Fig. 13BThe conductor neck 1126 is shown extending beyond the edge of the first insulating layer 1111 and protruding through the first insulating layer opening 1113. The conductor neck 1126 includes a first bend 1131 near the conductor trace 1128 and a second bend 1132 near the conductor tab 1122. These bends are Fig. 13C and Fig.13D In some examples, the conductor neck 1126 includes one or more first partial openings 1141 at the first bend 1131 and / or one or more second partial openings 1142 at the second bend 1132. Specifically, Fig. 13C The figure shows an example in which five first partial openings 1141 are located on the inner radius of the first curved portion 1131 . Fig.13D Another example is illustrated in which seven first partial openings 1141 are located on the outer radius of the first bend 1131. In some examples, the first partial openings 1141 can be located on both sides of the first bend 1131. Similarly, the second partial openings 1142 can be located on the inner radius of the second bend 1132, on the outer radius of the second bend 1132, or on both. In addition, any number of partial openings are within this range (e.g., one, two, three, four, etc.). Increasing the number of partial openings can help improve the flexibility of the conductor neck 1126 while keeping the cross-section of each partial opening relatively small. It should be noted that increasing the cross-section of the partial openings will increase the resistance of the conductor neck 1126 and reduce the mechanical strength of the conductor neck 1126. In some examples, the first partial opening 1141 includes one or more slits extending across the conductor neck 1126 (between opposite edges). In more specific examples, the depth of the plurality of slits is between approximately 10% and 40% of the total thickness of the conductor neck 1126 , or more specifically between 15% and 35% or even between 20% and 30%.

[0124] In some examples, the conductor neck 1126 can be used as a fuse, such as FIG. 14A to FIG. 14C Specifically, the conductor neck 1126 includes one or more partial openings 1160 located away from the conductor trace 1128 and the conductor tab 1122. For example, the partial opening 1160 is located on a portion of the conductor neck 1126 having a constant width (W1), such as Fig.14AAs shown. Each of the one or more partial openings 1160 has a controlled depth and a controlled width so that the conductor neck 1126 can be used as a fuse. The combination of the depth (D) and width (W2) of each opening 1160 and the width (W1) of the conductor neck 1126, the thickness (T) of the conductor neck 1126, and the material of the conductor neck 1126 defines the resistance and the current rating of the fuse. In other words, each opening 1160 corresponds to the minimum cross-section of the conductor neck 1126. The area and length of the cross section are controlled by the various parameters listed above, for example, the cross-sectional area = W1*(T–D), and the length of the cross section is the same as the width (W2) of the opening 1160. In some examples, each of the one or more partial openings 1160 extends across the conductor neck 1126.

[0125] in conclusion

[0126] The methods and apparatus described herein may be extended to the interconnection of general electronic devices, including but not limited to integrated circuits, resistors, capacitors, inductors, photovoltaic cells, and other electronic components and / or power supplies.

[0127] It should be understood that the above description is intended to be illustrative, rather than restrictive. For example, the above examples (and / or aspects thereof) can be used in combination with each other. In addition, many modifications that adapt specific situations or materials to the teachings proposed herein can be made. The size, material type, orientation, and quantity and position of the various components described herein are intended to define the parameters of some examples, and are by no means restrictive and are merely examples. After reading the above description, it will be clear to those skilled in the art that many examples and modifications within the spirit and scope of the claims.

Claims

1. A multi-layer flexible interconnect, comprising: a first insulating layer; a second insulating layer; A first conductive layer, which is disposed between the first insulating layer and the second insulating layer and directly contacts the first insulating layer; as well as A second conductive layer is disposed between the first conductive layer and the second insulating layer and directly interfaces with each of the first conductive layer and the second insulating layer, wherein: The first conductive layer has a thickness of at least 300 microns, and The first insulating layer and the second insulating layer are directly adhered to each other, forming a boundary around a portion of the first conductive layer and a portion of the second conductive layer, thereby maintaining the orientation of the first conductive layer and the second conductive layer relative to each other. 2 . The multi-layer flexible interconnect of claim 1 , wherein the first conductive layer and the second conductive layer are welded together at a plurality of welding locations separated from each other.

3. The multi-layer flexible interconnect according to claim 2, wherein: The second insulating layer includes a welding opening; and Each of the plurality of welding locations is located within a welding opening.

4. The multi-layer flexible interconnect of claim 1, wherein: The first conductive layer has a uniform thickness across the entire boundary of the first conductive layer; and The second conductive layer has a uniform thickness across an entire boundary of the second conductive layer.

5. The multilayer flexible interconnect of claim 1 , wherein at least one of the first conductive layer and the second conductive layer comprises a flexible tab, each flexible tab comprising a contact pad for connecting to the first conductive layer and the second conductive layer and protruding beyond a boundary of the first insulating layer and the second insulating layer.

6. The multi-layer flexible interconnect of claim 1, wherein at least one of the first insulating layer and the second insulating layer comprises polyethylene.

7. The multi-layer flexible interconnect of claim 1, wherein the first insulating layer and the second insulating layer both comprise polyethylene.

8. The multi-layer flexible interconnect according to claim 7, wherein: The polyethylene of the first insulating layer forms a first adhesive sublayer facing the second insulating layer, The polyethylene of the second insulating layer forms a second adhesive sub-layer facing the first insulating layer and directly adhered to the first insulating layer, thereby forming a border around a portion of the first conductive layer and a portion of the second conductive layer.

9. The multi-layer flexible interconnect of claim 8, wherein: The first adhesive sublayer is further adhered to the first conductive layer, and The second adhesive sub-layer is further adhered to the second conductive layer.

10. The multi-layer flexible interconnect of claim 1, wherein the first insulating layer comprises a solder opening exposing a portion of the first conductive layer.

11. The multi-layer flexible interconnect of claim 1 , further comprising: a third conductive layer; as well as A third insulating layer, wherein the third conductive layer is located between the second insulating layer and the third insulating layer, such that the third insulating layer isolates the third conductive layer from the environment and supports the third conductive layer relative to the second insulating layer.

12. The multi-layer flexible interconnect of claim 11, wherein the third conductive layer comprises aluminum.

13. The multi-layer flexible interconnect of claim 1, wherein the first conductive layer has a thickness of at least 350 microns.

14. The multi-layer flexible interconnect of claim 1, wherein the first conductive layer and the second conductive layer have the same thickness.

15. The multi-layer flexible interconnect of claim 1, wherein the first conductive layer and the second conductive layer have different thicknesses.

16. The multi-layer flexible interconnect of claim 1, further comprising a connector having terminals connected to the first conductive layer and the second conductive layer.

17. The multilayer flexible interconnect of claim 16, wherein the terminals of the connector are connected to the first and second conductive layers using transition traces having a different composition than the first and second conductive layers.

18. The multi-layer flexible interconnect of claim 1, wherein at least one of the first conductive layer and the second conductive layer is formed of aluminum.

19. The multi-layer flexible interconnect of claim 1, wherein the first conductive layer and the second conductive layer are both formed of aluminum.

20. The multi-layer flexible interconnect of claim 1, wherein the multi-layer flexible interconnect is configured for currents greater than 100A.

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