Conductive strap for battery pack

Abstract

A conductive strap for a battery pack including a pair of contact tabs and a notched portion. The contact tabs are separated by a separation gap defined in the conductive strap. Each contact tab includes at least one contact recess. The separation gap is contiguous with the notched portion. The notched portion and the separation gap are surrounded by the conductive strap. The notched portion includes an arcuate slot that partially surrounds the contact tabs.

Description

[Technical Field]

[0001] (Reference to Related Application) This application claims priority to the earlier, co-pending U.S. Provisional Patent Application No. 63 / 178,829, filed April 23, 2021, U.S. Provisional Patent Application No. 63 / 183,267, filed May 3, 2021, and U.S. Provisional Patent Application No. 63 / 292,145, filed December 21, 2021, the entire contents of which are incorporated herein by reference.

[0002] (Technical field) The present invention relates to conductive straps, and more particularly to conductive straps for battery packs. [Background technology]

[0003] When forming a conductive strap that electrically connects one or more battery cells to each other or to other components of the battery pack, it is important to provide good electrical conduction. In many applications, it is also beneficial to provide sufficient thermal conduction through the conductive strap so that the conductive strap can act as a heat sink for heat generated by electricity moving to and / or from the battery cells. To provide the best possible heat sinking capability, the conductive strap should be made of as much material as possible to provide a large enough cross-sectional area to effectively draw heat away from the battery cells, particularly along the current-carrying path.

[0004] Also, in forming the conductive strap, it may be beneficial to provide the conductive strap with contact tabs that are at least somewhat flexible relative to the rest of the conductive strap. These contact tabs should be sufficiently flexible to allow a welding head to press each contact tab into engagement with the end of a corresponding battery cell. The contact tabs and the end of the battery cell are then resistance welded together by the welding head. It is generally true with this manufacturing technique that the more flexible the contact tabs are relative to the rest of the conductive strap, the easier and better quality the welding operation will be.

[0005] The present disclosure takes into account and balances these two desirable configurations. Since increased flexibility often means reduced cross section, one or more arrangements and configurations of conductive straps are sought herein to provide optimization of both thermal conductivity and flexibility for manufacturing. Summary of the Invention

[0006] In one aspect, the present invention provides a conductive strap for a battery pack, the conductive strap including a pair of contact tabs and a cutout portion. The contact tabs are separated by a separation gap defined in the conductive strap. Each contact tab includes at least one contact recess. The separation gap is continuous with the cutout portion. The cutout portion and the separation gap are enclosed by the conductive strap. The cutout portion includes an arcuate slot that partially surrounds the contact tabs.

[0007] In another aspect, the present invention provides a conductive strap for a battery pack having a plurality of battery contacts, each battery contact having at least one contact tab, each contact tab having at least one contact recess, a subset of the battery contacts including more than one contact tab, and at least one battery contact including a single contact tab.

[0008] In yet another aspect, the present invention provides a method for mounting a conductive strap onto a battery cell. The method includes aligning a pair of contact tabs of the conductive strap with an edge of the battery cell. The pair of contact tabs is at least partially surrounded by an arcuate slot. A welding header then presses the pair of contact tabs of the conductive strap toward the edge of the battery cell. Next, a connection extension piece corresponding to each contact tab is deflected to independently move the contact tab relative to the remainder of the conductive strap. This action engages the edge of the battery cell with a contact recess in the contact tab. Finally, the pair of contact tabs is resistance welded to the edge of the battery cell at the contact recess. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a plurality of conductive straps for a battery pack according to an embodiment disclosed herein.

[0010] [Figure 2] FIG. 2 is a plan view of the conductive strap of FIG. 1.

[0011] [Figure 3] FIG. 2 is an exploded perspective view of the conductive strap of FIG. 1.

[0012] [Figure 4] 2 is a perspective view of the conductive strap of FIG. 1 disposed within an overmolded body of a battery pack. FIG.

[0013] [Figure 5] 2 is a cross-sectional side view of the conductive strap of FIG. 1 being resistance welded to a respective battery cell of a battery pack.

[0014] [Figure 6] 1 illustrates an assembly process for a conductive strap assembly.

[0015] [Figure 7] 2 is a welded conductive strap assembly of a plurality of conductive straps of FIG. 1.

[0016] [Figure 8] FIG. 1 is a perspective view of a conductive strap for a battery pack according to an embodiment disclosed herein.

[0017] [Figure 9] FIG. 9 is a plan view of the conductive strap of FIG. 8.

[0018] [Figure 10] FIG. 9 is a side view of the conductive strap of FIG. 8.

[0019] [Figure 11] 9 is another perspective view of the conductive strap of FIG. 8.

[0020] [Figure 12] FIG. 10 is a plan view of another conductive strap for a battery pack according to embodiments disclosed herein.

[0021] [Figure 13] FIG. 10 is a plan view of yet another conductive strap for a battery pack according to embodiments disclosed herein.

[0022] [Figure 14] FIG. 10 is a plan view of another conductive strap for a battery pack according to embodiments disclosed herein.

[0023] [Figure 15] FIG. 10 is a plan view of yet another conductive strap for a battery pack according to embodiments disclosed herein.

[0024] [Figure 16] FIG. 10 is a plan view of yet another conductive strap for a battery pack according to embodiments disclosed herein.

[0025] [Figure 17] FIG. 10 is a detailed plan view of another conductive strap for a battery pack according to embodiments disclosed herein.

[0026] [Figure 18] FIG. 18 is another detailed plan view of the conductive strap of FIG. 17.

[0027] [Figure 19] 2 is a first gradient map illustrating directional deformation and a second gradient map illustrating current density of the conductive strap of FIG. 1;

[0028] [Figure 20] 14 is a first gradient map showing directional deformation and a second gradient map showing current density of the conductive strap of FIG. 13;

[0029] [Figure 21] FIG. 9 is another plan view of the conductive strap of FIG. 8 with various measurements annotated thereon, the measurements being in millimeters.

[0030] [Figure 22] FIG. 22 is a detailed plan view of area 22 shown in FIG. 21.

[0031] [Figure 23] FIG. 22 is a detailed plan view of area 23 shown in FIG. 21.

[0032] [Figure 24] FIG. 9 is a side view of the conductive strap of FIG. 8 with various measurements annotated thereon, the measurements being in millimeters.

[0033] [Figure 25] FIG. 25 is a detailed side view of area 25 shown in FIG. 24.

[0034] [Figure 26] FIG. 2 is a plan view of a conductive strap for a battery pack according to an embodiment disclosed herein.

[0035] [Figure 27] FIG. 2 is a plan view of a conductive strap for a battery pack according to an embodiment disclosed herein.

[0036] [Figure 28] FIG. 10 is a plan view of another conductive strap for a battery pack according to embodiments disclosed herein.

[0037] [Figure 29] FIG. 10 is a plan view of another conductive strap for a battery pack according to embodiments disclosed herein.

[0038] [Figure 30] FIG. 1 is a perspective view of a conductive strap for a battery pack according to an embodiment disclosed herein.

[0039] [Figure 31] FIG. 31 is a plan view of the conductive strap of FIG. 30.

[0040] [Figure 32] 10 is a gradient map illustrating current density in a conductive strap for a battery pack according to embodiments disclosed herein.

[0041] [Figure 33] 31 is a gradient map showing current density for the conductive strap of FIG. 30.

[0042] [Figure 34] 10 is a gradient map illustrating current density for various conductive straps according to embodiments disclosed herein.

[0043] [Figure 35]1 is a table of flexibility measurements for various conductive straps according to embodiments disclosed herein.

[0044] [Figure 36] FIG. 1 is a perspective view of a battery pack according to one embodiment of the present disclosure.

[0045] [Figure 37] FIG. 37 is an enlarged view of the battery pack of FIG. 36. DETAILED DESCRIPTION OF THE INVENTION

[0046] The configuration and aspects of the present disclosure will become apparent from the following detailed description and the accompanying drawings.

[0047] Before any embodiments of the present disclosure are described in detail, it is to be understood that the disclosure is not limited in its application to the details of the arrangement and construction of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0048] 1-3, one embodiment of a conductive strap assembly 100 for use with a battery pack is shown. Depending on the number of battery cells, the conductive strap assembly 100 may include one or more conductive straps 102. Each conductive strap 102 includes at least one pair of contact tabs 104. Each contact tab 104 includes one or more contact dimples 106 arranged to protrude toward the adjacent edge of the battery cell (discussed further below). Each conductive strap 102 may be manufactured, for example, by stamping a shape from a sheet of metal. The conductive strap 102 may include multiple mounting holes 108 defined therein for fastening the conductive strap 102 to other components of the battery pack. In the illustrated embodiment, some of the mounting holes 108 are defined in mounting tabs 110 that protrude from the remainder of the conductive strap 102.

[0049] As best shown in FIG. 2 , each conductive strap 102 may have a generally planar, sheet-like shape. In the illustrated embodiment, each contact tab 104 is formed in a concave shape, such as a large portion of a recessed or concave semicircle, on the same side of the conductive strap. In the illustrated embodiment, the contact tabs 104 have a truncated semicircular shape. A separation gap 112 is defined in the conductive strap 102 and is disposed between each pair of contact tabs 104. In the illustrated embodiment, the separation gap 112 is continuous with a cutout portion. The cutout portion includes a first cutout portion 116 at one end of the separation gap 112 and a second cutout portion at the other end of the separation gap 112. The second cutout portion is a circular hole 114. The separation gap 112 and the cutout portion 116 are enclosed by the conductive strap 102. The separation gap 112 and the enclosed area around the cutout portion 116 may be circular. The separation gap 112, the circular hole 114, and the cutout portion 116 all cooperate to provide improved flexibility of the contact tabs 104. The contact tabs 104 may be asymmetric. The radial asymmetry provided to each contact tab due to the cutout portion 116 being located away from the current-carrying path allows for an increase in the cross-sectional area of ​​the contact tab around the current-carrying path while maintaining a sufficient amount of flexibility. In that way, improved thermal conductivity is also achieved, even with improved flexibility.

[0050] 4, the conductive strap 102 can be insert molded or overmolded into the battery pack's structural member 118. This manufacturing technique allows for enhanced stability to avoid weld failure due to vibration. Additionally, insert molding the conductive strap 102 helps position the contact tabs 104 for the welding process described below.

[0051] Referring to FIG. 5 , the welding process is shown. The conductive strap 102 is already insert molded into the structural member 118 of the battery pack. The battery cells 120 are inserted into the cavities of the structural member 118. The pairs of contact tabs 104 are aligned with the ends of the battery cells 120. The weld headers 122 press against the outer surfaces of the conductive straps 102. Specifically, the weld headers 122 press against the contact tabs 104. The pressing force applied by the weld headers 122 moves the contact tabs 104 toward the ends of the battery cells 120. The connection extension pieces corresponding to each of the contact tabs 104 are flexed, moving the contact tabs 104 independently relative to the rest of the conductive strap 102, thereby engaging the ends of the battery cells 120 with the contact recesses 106 of the contact tabs 104. Current is then passed through the contact tabs 104 to resistance weld the contact dimples 106 to the edges of the battery cells 120 .

[0052] 6, corner straps 124 are shown bent over and covering conductive straps 102. This two-layer strap design allows for a reduced likelihood of overheating of battery cells 120 adjacent to corner straps 124 compared to a single-layer design.

[0053] 3 and 7, an embodiment including two corner straps 124, 126 is shown. Each of the corner straps 124, 126 in the illustrated embodiment also has a single pair of contact tabs 104. The longer corner strap 124, which is positioned over the outside of the shorter corner strap 126, includes a window opening 128 therein. In this manner, the weld header 122 can still reach the contact tab 104 of the shorter corner strap 126 to resistance weld the contact dimple 106 to the edge of the battery cell 120. In this illustrated configuration, the contact tab 104 of the shorter corner strap 126 is positioned between the battery cell 120 and the portion of the longer corner strap 124 that defines the window opening 128. As shown in FIG. 7, the two corner straps 124, 126 are welded together using, for example, laser welding, to enable increased heat transfer between the two layers provided by the two corner straps 124, 126. Additionally, the two layers provided by the two corner straps 124, 126 provide additional strap material that reduces the likelihood of adjacent battery cells 120 overheating. The additional material provided by the two-layer design provides better heat transfer capabilities than a single layer while still allowing the contact tabs 104 to flex sufficiently for welding to the battery cells 120. This two-layer structure also provides improved current carrying capabilities compared to a single layer. In some embodiments, each of the two corner straps 124, 126 is 0.25 millimeters thick. When laser welded together, the corner straps 124, 126 form a single section having a thickness of 0.5 millimeters.

[0054] FIG. 19 shows the directional deformation of a set of conductive straps 102 after the set is welded to the ends of the battery cells 120 and illustrates the current density of the set of conductive straps 102 during operation. During welding, the weld header 122 contacts the set of conductive straps 102 at four different locations (e.g., on each pair of contact tabs 204), and a welding force ranging from 31 Newtons to 58.1 Newtons can be used to deform the set of conductive straps 102. The maximum negative deformation of the conductive straps 102 (i.e., deformation toward the battery cells 120) occurs at the contact tabs 104. The maximum positive deformation of the conductive straps 102 (i.e., deformation away from the battery cells 120) occurs at the attachment tabs 110. In some embodiments, the deformation can range from -0.51 millimeters to 0.12 millimeters. The current density of the conductive strap 102 was a baseline current of 30,000 mA (milliamperes), an average voltage of 1.82 mV (millivolts), and a current density of 6.1×10 (-5) The current density was measured using a resistance of Ω (ohms). In some embodiments, the current density was 0 mA / mm 2 ~31382 / mm 2 and in some embodiments, the current density is in the range of 0 mA / mm 2 ~17435 / mm 2 The highest current density in the conductive strap 102 may occur around the depression 106 and the circular hole 114.

[0055] 8, another embodiment of conductive strap 202 is shown. Many features of conductive strap 202 are similar to those discussed above with respect to the first embodiment of conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 100 higher than the corresponding features discussed above.

[0056] As best shown in FIG. 9 , the conductive strap 202 provides greater flexibility for the contact tabs 204. This flexibility is due to the arcuate slots 230 defined within the conductive strap 202. The arcuate slots 230 at least partially surround each contact tab 204. The arcuate slots 230, the first cutout portions 216, and the separation gaps 212 are continuous. Furthermore, the cutout portions 216 are no longer surrounded by additional strap material. Instead, each cutout portion 216 forms a portion of the overall circumference of the conductive strap 202, thereby reducing material in the portions of the conductive strap 202 that are not disposed in the current-carrying path. In the illustrated embodiment, the width W1 of the conductive strap 202 at the current-carrying location is between 5 millimeters and 10 millimeters. Some embodiments include a width W1 between 7 millimeters and 8 millimeters. Some embodiments include a width W1 that is 7.83 millimeters.

[0057] As shown in FIG. 10 , the conductive strap 202 further includes a contact tab 204 that is recessed relative to the remainder of the conductive strap 202. An angled extension connects the contact tab 204 to the remainder of the conductive strap 202. The conductive strap defines a conductive strap plane P1, while the contact tab 204 defines a contact tab plane P2 that is parallel to and offset from the conductive strap plane P1. The angled extension spans between the conductive strap plane P1 and the contact tab plane P2. The contact tab plane P2 may be offset from the conductive strap plane P1 by a distance ranging from 0.5 millimeters to 2.0 millimeters.

[0058] Because the positive ends of some battery cells 120 protrude longitudinally farther than the negative ends of the cells, the illustrated embodiment has contact tabs 204 recessed to different depths to correspond to the ends of each battery cell 120. Thus, the illustrated embodiment includes a recess depth D1 for the contact tab 204 corresponding to the positive end of the battery cell 120 that is shorter than a recess depth D2 for the contact tab 204 corresponding to the negative end of the battery cell 120. In some embodiments, the shorter recess depth D1 is between 0.5 millimeters and 1.5 millimeters, and the longer recess depth D2 is between 1.5 millimeters and 2.5 millimeters. In some embodiments, the shorter recess depth D1 is between 0.75 millimeters and 1.25 millimeters, and the longer recess depth D2 is between 1.5 millimeters and 2.0 millimeters. In some embodiments, the shorter recess depth D1 is 1 millimeter, and the longer recess depth D2 is 1.55 millimeters. These unequal recess depths D1, D2 allow for improved welding between the contact tab 204 and each end of the battery cell 120. Of course, other embodiments may include equal recess depths D1, D2 to accommodate battery cells 120 that do not protrude farther at the positive end than at the negative end. As seen in FIG. 24 , in some embodiments, the mounting holes 208 may extend beyond the conductive strap 202 by a height H1 ranging from 1.00 millimeters to 0.10 millimeters. In some embodiments, the height H1 may range from 0.50 millimeters to 0.30 millimeters. In a preferred embodiment, the height H1 is 0.37 millimeters. Additionally, as seen in FIG. 25 , the recess 206 may extend beyond the recess depths D1, D2 of the contact tab 204. In some embodiments, this additional depth D6 may range from 1.0 millimeters to 0.1 millimeters. In some embodiments, the additional depth D6 may range from 0.6 millimeters to 0.2 millimeters. In a preferred embodiment, the depth D6 is 0.3 millimeters.

[0059] As seen in FIGS. 21-23 , in some embodiments, the diameter of the mounting hole 208 ranges from 2.5 millimeters to 4.5 millimeters. In some embodiments, the diameter of the mounting hole 208 ranges from 3.0 to 4.0 millimeters, and in some embodiments, the diameter ranges from 3.4 to 3.6 millimeters. In some embodiments, the length L1 between the mounting hole 208 and the separation gap 212 can range from 11.0 millimeters to 9.00 millimeters. In some embodiments, the length L1 can range from 10.00 millimeters to 9.5 millimeters. In some embodiments, the length L1 can be 9.85 millimeters. Additionally, in some embodiments, the length L2 between the first mounting hole 208a and the second mounting hole 208a can range from 22 mm to 18 mm. In some embodiments, the length L2 can range from 21 to 20 millimeters. In some embodiments, the length L2 can be 20.20 millimeters. In some embodiments, a width W4 between the first mounting hole 208a and the third mounting hole 208c can range from 25 millimeters to 22 millimeters. In some embodiments, the width W4 can range from 24 millimeters to 23 millimeters. In some embodiments, the width W4 can be 23.9 millimeters. A center point 234 is located between the recesses 206. The center point 234 can be aligned with the center point of the edge of the battery cell 120. In some embodiments, a length L3 between the recess 206 and the separation gap 212 can range from 1.00 millimeters to 3.00 millimeters. In some embodiments, the length L3 can be approximately 1.55 millimeters. In some embodiments, the length L3 can be approximately 2.29 millimeters. In some embodiments, a width W5 between the center point 234 and the recess 206 can range from 2.00 millimeters to 0.5 millimeters. In some embodiments, the width W5 can be approximately 1.44 millimeters. In some embodiments, the width W5 may be about 0.85 millimeters.The contact tab 204 (FIG. 23) with the indentations 206 closer together may correspond to the positive end of the battery cell 120, while the contact tab 204 (FIG. 22) with the indentations 206 further apart may correspond to the negative end of the battery cell 120. Length L4 is between the indentations 206 and the farthest edge of the contact tab 204. In some embodiments, length L4 may range from 1.0 to 3.0 millimeters. In some embodiments, length L4 may range from 2.0 to 3.0 millimeters. In some implementations, length L4 is 2.28 millimeters. In some embodiments, separation gap 212 may have a thickness ranging from 2.00 millimeters to 0.5 millimeters. In some embodiments, separation gap 212 may have a thickness ranging from 1.5 millimeters to 0.75 millimeters. In some embodiments, separation gap 212 may have a thickness of 1 mm. In some embodiments, circular hole 214 may have a diameter ranging from 2.00 millimeters to 4.00 millimeters. In some embodiments, circular hole 214 may have a diameter ranging from 3.00 millimeters to 4.00 millimeters. In some embodiments, circular hole 214 has a diameter of 3.00 millimeters. An angle A3 is formed between centerline 238 of center point 234 and the end of arcuate slot 230. In some embodiments, angle A3 may range from 20 degrees to 10 degrees. In some embodiments, angle A3 may range from 17 degrees to 15 degrees. In some embodiments, angle A3 may be 16 degrees. In some embodiments, the distance between mounting hole 208 and circular hole 214 may range from 15.00 millimeters to 12.00 millimeters, while in some embodiments, this distance may range from 13.00 millimeters to 12.00 millimeters. In some embodiments, the distance between mounting hole 208 and circular hole 214 is 13.5 millimeters. In some embodiments, the distance between center point 234 and the circular hole can range from 4.00 to 6.00 millimeters. In some embodiments, the distance between center point 234 and the circular hole can range from 5.00 to 5.50 millimeters, while in some embodiments, the distance is 5.17.

[0060] 12, yet another embodiment of conductive strap 302 is shown. Many features of conductive strap 302 are similar to those discussed above with respect to the first embodiment of conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 200 higher than the corresponding features discussed above.

[0061] 8-11, except that the arcuate slots 330 are at least partially surrounded by extended sections 332. These extended sections 332 increase the amount of material in the conductive strap 302. Because the extended sections 332 are separated from the contact tabs 304 by the arcuate slots 330, the improved flexibility of the contact tabs 304 is maintained, while the additional material provided by the extended sections 332 provides additional material for dissipating heat.

[0062] 13, yet another embodiment of a conductive strap 402 is shown. Many features of the conductive strap 402 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 300 higher than the corresponding features discussed above.

[0063] 8-11, except that conductive strap 402 does not have an arcuate slot. This embodiment may be easier and / or cheaper to manufacture than conductive strap 202, while maintaining satisfactory performance in terms of both thermal conductivity and flexibility of contact tabs 404 for the current path.

[0064] FIG. 20 illustrates the directional deformation of the conductive straps 402 after the set of conductive straps 402 has been welded to the set of battery cells 420, showing the current density of the set of conductive straps 402 during operation. During welding, the weld header 122 contacts the set of conductive straps 402 at six different locations (e.g., at each pair of contact tabs 404) and uses a welding force ranging from 7.9 Newtons to 43.2 Newtons. The maximum negative deformation of the conductive straps 402 (i.e., deformation toward the battery cells 120) occurs at the attachment tabs 410. The maximum positive deformation of the conductive straps 402 (i.e., deformation away from the battery cells 120) occurs on the contact tabs 402. In some embodiments, the deformation can range from -0.02 millimeters to 0.39 millimeters. The current density of the conductive straps 402 is measured with a baseline current of 30,000 milliamperes (mA), an average voltage of 0.97 millivolts (mV), and a mean voltage of 3.23×10 -5 The current density was measured using a resistance of Ω (ohms). In some embodiments, the current density was 0 mA / mm 2 ~18953 / mm 2 and in some embodiments, the current density is in the range of 0 mA / mm 2 ~8423.7 / mm 2 The maximum current density in the conductive strap 402 may occur around the circular hole 414.

[0065] 14, yet another embodiment of a conductive strap 502 is shown. Many features of the conductive strap 502 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 400 higher than the corresponding features discussed above.

[0066] The conductive strap 502 is similar to the conductive strap 102 shown in FIGS. 1-3, except that the conductive strap 502 does not have a circular hole. Instead, the conductive strap 502 includes two cutout portions 516 defined therein on opposite sides of the contact tab 504. The cutout portions 516 also communicate with the separation gap 512 such that the contact tabs 504 are rectangular in shape. In some embodiments, each of the rectangular contact tabs 504 has a width W2 between 7 millimeters and 12 millimeters. In some embodiments, the width W2 is between 8 millimeters and 11 millimeters. In some embodiments, the width W2 is between 9 millimeters and 10 millimeters. In some embodiments, the width W2 is 9.52 mm. In some embodiments, the diameter D3 of the arc formed by the outermost edges of the cutout portions 516 (e.g., the generally circular enclosed area including the separation gap 512 and the cutout portions 516) is between 12 mm and 17 mm. In some embodiments, diameter D3 is between 13 millimeters and 15 millimeters. In some embodiments, diameter D3 is 14 mm. In some embodiments, diameter D3 is 14.026 mm.

[0067] 15, another embodiment of a conductive strap 602 is shown. Many features of the conductive strap 602 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 500 higher than the corresponding features discussed above.

[0068] Conductive strap 602 is similar to conductive strap 102 shown in FIGS. 1-3, except that conductive strap 602 includes a differently shaped cutout portion 616. Cutout portion 616 is shaped so that the ends of each contact tab of contact tab 604 meet at a point. Contact tab 604 is generally triangular in shape, with the electrical path running through the wide base of the triangle. In some embodiments, angled contact tab 604 meets at a point having an angle A1 between 45 and 65 degrees. Some embodiments include an angle A1 between 50 and 60 degrees. Some embodiments include an angle A1 of 55 degrees. In some embodiments, a diameter D4 of the arc formed by the outermost edge of cutout portion 616 is between 12 and 17 mm. In some embodiments, diameter D4 is between 13 and 15 mm. In some embodiments, diameter D4 is 14 mm. In some embodiments, diameter D4 is 14.036 mm.

[0069] 16, another embodiment of conductive strap 702 is shown. Many features of conductive strap 702 are similar to those discussed above with respect to the first embodiment of conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 600 higher than the corresponding features discussed above.

[0070] Conductive strap 702 is similar to conductive strap 102 shown in FIGS. 1-3, except that conductive strap 702 includes a differently shaped cutout portion 716. The cutout portion 716 is arcuately shaped to provide a rounded end to each contact tab of contact tabs 704. Contact tabs 704 are generally semicircular in shape, and the current carrying path is through a connecting extension that intersects with the semicircular portion of contact tab 704. In some embodiments, angle A2 of the base of the pair of contact tabs 704 (e.g., the angle between the connecting extension and each contact tab) is between 70 and 90 degrees. Some embodiments include angle A2 between 75 and 85 degrees. Some embodiments include angle A2 of 78 degrees. Separation gap 712 and circular hole 714 are included within angle A2. In some embodiments, diameter D5 of the arc formed by the outermost edge of cutout portion 716 is between 12 and 17 millimeters. In some embodiments, diameter D5 is between 13 millimeters and 15 millimeters. In some embodiments, diameter D5 is 14 mm. In some embodiments, diameter D5 is 14.045 mm.

[0071] 17 and 18 illustrate detailed perspective views of another conductive strap 802. Many features of the conductive strap 802 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 700 higher than the corresponding features discussed above.

[0072] The conductive strap 802 includes a different layout of the contact dimples 806 for the positive end of the battery cell 120 compared to the contact dimples 806 for the negative end of the battery cell 120. That is, one set of contact dimples 806 is farther away from the circular holes 814 than another set of contact dimples 806 is from each other's respective circular holes 814. In some embodiments, the longer distance provides a route R1 from a first contact dimple 806 on a first contact tab, around the circular holes 814, to a second contact dimple 806 on a second adjacent contact tab 804 separated from the first contact tab 804 by a separation gap 812. This route R1 is between 17.5 millimeters and 20 millimeters. In some embodiments, this route R1 is between 18 millimeters and 19 millimeters. In some embodiments, this route R1 is 18.11 millimeters. In some embodiments, the shorter distance provides a route R2 from one contact indentation 806 around the circular hole 814 to another contact indentation 806 on an adjacent contact tab 804 separated by a common separation gap 812. This route R2 is between 16.5 millimeters and 18 millimeters. In some embodiments, the route R2 is between 17 millimeters and 18 millimeters. In some embodiments, the route R2 is 17.14 millimeters.

[0073] As shown in FIG. 18 , the conductive strap 802 also includes a width W3 of the conductive strap 802 along which the current-carrying path travels. The width W3 may be defined as the width between the edge of the conductive strap 802 and the outermost edge of the notched portion 816. In some embodiments, the width W3 is between 4 millimeters and 6 millimeters. In some embodiments, the width W3 is between 4.5 millimeters and 5.5 millimeters. In some embodiments, the width W3 is 5 millimeters. In some embodiments, the width W3 is 5.0166 mm. In some embodiments, the width W3 may be greater than 6 millimeters. Some embodiments include a width W3 between 6.5 millimeters and 10.5 millimeters. Some embodiments include a width W3 between 7.5 millimeters and 9.5 millimeters. Some embodiments include a width W3 of 8.35 millimeters.

[0074] 30-31, yet another embodiment of a conductive strap 902 is shown. Many features of the conductive strap 902 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 800 higher than the corresponding features of the conductive strap 102 discussed above.

[0075] The conductive strap 902 differs from the conductive strap 202 shown in FIGS. 8-11 in that the conductive strap 902 has an end piece 936 that is positioned differently from the remainder of the strap 902. The conductive strap 902 has multiple battery cell contact portions, including at least one contact tab 904. Each contact tab 904 has at least one indentation 906. The end piece 936 may be attached to a corner battery cell 920. The conductive strap 202 may have more than one end piece 936. On the end piece 936, there is only a single contact tab 904 that covers half of the battery cell 920, while the remainder of the strap has a pair of contact tabs 904 that cover most of the end of each remaining battery cell 920, as shown in FIG. 30 . In other words, a subset of the battery contact portions includes more than one contact tab 904, while at least one battery contact portion (e.g., end piece 936) includes a single contact tab 904. The subset of battery contact portions may include all battery contact portions except one battery contact portion (e.g., end piece 936). Compared to the remainder of the strap 902, the end piece 936 has a different arrangement. For example, the end piece 936 may have half the number of contact dimples 906 compared to the remainder of the strap 902. Furthermore, the remainder of the strap 902 has separation gaps 912 between the contact tabs 904 and the notched portions 916 defined in the conductive strap 902. As shown in FIGS. 32-33 , the current flow path and overall resistance of the conductive strap 902 are similar to the current flow path and overall resistance of the conductive strap 202. During manufacturing, the weld header 122 contacts both the cell head 920 and the conductive strap 902 when welding the end piece 936. This welding technique allows the weld header 122 to use lower forces compared to welding the rest of the conductive strap 902. This embodiment may be cheaper to manufacture than the conductive strap 202 because the amount of material is reduced.FIG. 30 shows conductive strap 902 having contact tabs 904 with a geometric shape similar to the rectangular shape of contact tab 204, although other geometric shapes of contact tabs (e.g., the triangular geometric shape of contact tab 604 or the semicircular geometric shape of contact tab 704) may be used.

[0076] 26, another embodiment of a conductive strap 1002 is shown. Many features of the conductive strap 1002 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 900 higher than the corresponding features of the conductive strap 102 discussed above.

[0077] 1-3 in that the conductive strap 1002 has a larger current path. The current path is increased by increasing the length L1 between the mounting holes 1008 and the separation gap 1012. This increases the amount of material on the conductive strap 1002 between each pair of contact tabs 1004 and between the battery cells 120. The larger current path allows the conductive strap 1002 to have less resistance losses and less heat losses during operation.

[0078] 27 shows another embodiment of a conductive strap 1102. Many features of the conductive strap 1102 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. As such, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 1000 higher than the corresponding features of the conductive strap 102 discussed above.

[0079] The conductive strap 1102 differs from the conductive strap 202 shown in FIGS. 8-11 in that the conductive strap 1102 has larger contact tabs 1104. The larger contact tabs 1104 allow the conductive strap 1102 to have more contact with the edges of the battery cells 120. This design also allows a larger current path to be formed on the conductive strap 1102. The larger current path allows the conductive strap 1102 to have less resistive losses and less thermal losses during operation. The larger contact tabs 1104 also allow the conductive strap 1102 to be used with larger battery cells 120. FIG. 34 shows a heat map of the current density of the conductive strap 1102 during operation. The current density of the conductive strap 1102 was measured at a baseline current of 30,000 mA (milliamps), an average voltage of 1.08 mV (millivolts), and a dc voltage of 3.59x10 -5 The highest current density may occur near the circular holes 1114 and near the arc-shaped slots 1130, as measured using a resistance in Ω (ohms).

[0080] 28 illustrates another embodiment of a conductive strap 1202. Many features of the conductive strap 1202 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. Accordingly, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 1100 higher than the corresponding features of the conductive strap 102 discussed above.

[0081] The conductive strap 1202 differs from the conductive strap 102 shown in FIGS. 1-3 in that the conductive strap 1202 has an elongated rectangular contact tab 1104. The elongated rectangular contact tab 1104 allows for more flexibility within the conductive strap 1202. In addition, the conductive strap 1202 has a larger cutout portion 1216. The larger cutout portion 1216 and the elongated rectangular tab 104 allow for less material to be used in the conductive strap 1202. FIG. 34 shows a heat map of the current density of the conductive strap 1202. The current density of the conductive strap 1202 was 30,000 milliamperes (mA), an average voltage of 2.08 millivolts (mV), and a 6.96x10 -5 The highest current density may occur near the circular hole 1214 and near the connection extension where the conductive tab 1204 connects with the rest of the conductive strap 102.

[0082] 29 illustrates another embodiment of a conductive strap 1302. Many features of the conductive strap 1302 are similar to those discussed above with respect to the first embodiment of the conductive strap 102. Accordingly, many of these features will not be discussed again below. Features similar to those discussed above are marked with reference numerals that are 1200 higher than the corresponding features of the conductive strap 102 discussed above.

[0083] 29 in that the conductive strap 1302 does not have a cutout portion surrounding the contact tab 1302. Additionally, the conductive strap 1302 has a generally more rectangular design. The slot 1330 is a straight slot instead of an arc-shaped slot. The rectangular design increases the current carrying path, allowing for less resistive loss and less heat loss when the conductive strap 1302 is in use.

[0084] Referring to FIG. 34 , the weld header 122 pressing force required to install the conductive straps 1202 and 1102 is shown from the perspective of the conductive strap 402. During installation, the conductive straps 1202 and 1102 may require less force from the weld header 122 than the conductive strap 402. The conductive strap 1202 can be installed using between 59% and 16.9% of the pressing force of the conductive strap 402. The weld header 122 can use a pressing force to install the conductive strap 1202 in the range of 25.4 Newtons to 1.34 Newtons. The conductive strap 1102 can be installed using between 40% and 17% of the pressing force of the conductive strap 402. The weld header 122 can use a pressing force to install the conductive strap 1102 in the range of 7.76 Newtons to 1.34 Newtons. This means that the conductive straps 1202 and 1102 are more flexible than the conductive strap 402.

[0085] FIG. 35 shows the flexibility of conductive straps 102, 1202, 1302, and 1102. Flexibility is measured in terms of negative and positive ranges. Conductive strap 102 has a negative range of approximately -0.27 to 0.73 millimeters and a positive range of -1.21 to 0.13 millimeters. Conductive strap 102 has a negative range of approximately -0.840 to 0.36 millimeters and a positive range of -1.26 to 0.64 millimeters. Conductive strap 1302 has a negative range of approximately -0.96 to 0.22 millimeters and a positive range of -1.38 to 0.5 millimeters. Finally, conductive strap 1102 has a negative range of approximately -0.62 to -0.02 millimeters and a positive range of -1.01 to 0.33 millimeters.

[0086] At least some of the embodiments disclosed herein maximize the amount of conductive strap material around the edge of each respective battery cell, maximizing the width of the current-carrying path. Insert molding the conductive strap into a structural member (such as a cell frame) of the battery pack may also enhance the ability to transfer heat away from the battery cell. With at least some of the embodiments disclosed herein, the contact tab provides a weld area on a majority of the positive end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​more than 75% of the positive end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​more than 85% of the positive end of the battery cell. In some embodiments, the contact tab provides a weld area between 85% and 90% of the positive end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​88.6% of the positive end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​more than 25% of the negative end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​more than 35% of the negative end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​35% to 45% of the negative end of the battery cell. In some embodiments, the contact tab provides a weld area of ​​39.5% of the negative end of the battery cell. At least some of the embodiments disclosed herein have a strap thickness of between 0.2 millimeters and 0.5 millimeters. In some embodiments, the strap thickness is between 0.2 millimeters and 0.3 millimeters. In some embodiments, the strap thickness is 0.25 millimeters. In some embodiments, the cross-sectional area of ​​the current-carrying path is between 1 square millimeter and 2 square millimeters. In some embodiments, the cross-sectional area of ​​the current-carrying path is between 1 square millimeter and 1.5 square millimeters. In some embodiments, the cross-sectional area of ​​the current-carrying path is 1.254 square millimeters.

[0087] 36 and 37 illustrate a battery pack 2000 according to some embodiments of the present disclosure. The battery pack 2000 includes battery pack electronics 2002, which includes a printed circuit board (PCB) 2100 and a conductive strap assembly 100 having one or more of the conductive straps 102 and corner straps 124, 126. The PCB 2100 may be connected to a circuit having one or more electrical components (e.g., a CPU, a transformer, an FET, etc.) that may be electrically connected to one or more battery cells 120. For example, the PCB 2100 may be coupled to a circuit configured to monitor battery characteristics, provide voltage detection, store battery characteristics, display battery characteristics, notify a user of certain battery characteristics, terminate current flow within the battery pack, detect temperature of the battery pack, battery cells, etc., transfer heat from and / or within the battery pack, and provide a method for balancing when an imbalance is detected within one or more battery cells. In some embodiments, the circuit may include a voltage detection circuit, a boost circuit, a charge status indicator, etc. The PCB 2100 may be fixably coupled to the housing or frame of the battery pack 2000 (eg, by welding) and may be supported by the housing or frame of the battery pack 2000.

[0088] In the illustrated embodiment of the battery pack 2000, the corner straps 124, 126 may include PCB contacts 125 ( FIGS. 1-3 ) fixably coupled to and extending from one end of the straps 124. In some embodiments, the PCB contacts 125 are integrally formed with the corner straps 124. The PCB contacts 125 are configured to couple to a PCB connector 2110. The PCB connector 2110 is supported on the battery pack 2000 and electrically connects with the PCB 2100. For example, the PCB connector 2110 may be fixably coupled to and extend from the PCB 2100 on one side of the PCB 2100 (e.g., by welding). An end of the PCB connector 2110 is positioned adjacent to the PCB contacts 125. Specifically, the illustrated PCB connector 2110 includes first and second weld plates 2114, 2118 ( FIG. 31 ) for electrically coupling the connector 2110 to the PCB contacts 125, and a raised portion 2122 positioned between the weld plates 2114, 2118 and extending along a parting line 2126 that extends above the contact surfaces of the PCB contacts 125. To facilitate electrical connection between the weld plates 2114, 2118 and the PCB contacts 125, each of the weld plates 2114, 2118 has a respective weld 2130, where each of the plates 2114, 2118 can be laser welded to the PCB contacts 125. After one of the plates 2114, 2118 is welded to the PCB contact 125, the current from the battery cell 120 is carried to the flexible circuit 2134, which electrically couples the PCB connector 2110 to the PCB 2100 so that, for example, the voltage and / or current status of the battery cell 120 can be monitored.

[0089] In some cases, if the PCB 2100 is deemed faulty, the user needs to disconnect the PCB 2100 from the battery pack 2000 via the PCB connector 2110. Typically, this requires the user to discard the entire PCB 2100 and PCB connector 2110 assembly because the PCB connector 2110 is typically solidly welded to the PCB contacts 125 in a single location and cannot be easily removed without potentially damaging the battery pack 2000. To address this issue, when the PCB 2100 is initially attached to the battery pack 2000, the first weld plate 2114 of the PCB connector 2110 is laser welded to the PCB contacts 125, while the second weld plate 2118 remains unlaser welded to the PCB contacts 125, relying on the raised portion 2122 to electrically couple the first weld plate 2114 to the PCB connector 2110 and subsequently to the PCB 2100. Thus, if the PCB 2100 is deemed faulty, the user can simply cut the raised portion 2122 along the parting line 2126 to easily remove the faulty PCB 2100. Then, when the user is ready to install a new PCB 2100, the user can simply laser weld the second weld plate 2118 to the PCB contacts 125 to re-establish the electrical connection between the PCB connector 2100 and the battery pack 2000 without having to sacrifice any valuable components. This is advantageous because it saves both time and money on expensive components.

[0090] In other embodiments of battery pack 2000, battery pack 2000 includes any of the embodiments of conductive straps 202, 302, 402, 502, 602, 702, 802, 902, 1002, 1102, 1202, 1302 to facilitate electrical connection to PCB connector 2110. In other embodiments, battery pack 2000 can be a 12V, 18V, or 80V system, or any other common battery pack voltage system commonly known and used by those skilled in the art.

[0091] Various configurations of the present disclosure are set forth in the following claims.

Claims

1. 1. A conductive strap for a battery pack, comprising: The conductive strap defines a conductive strap plane, the conductive strap having: a pair of contact tabs separated by a separation gap defined in the conductive strap, each contact tab including at least one contact recess, the pair of contact tabs defining a contact tab plane, the contact tab plane being offset from the conductive strap plane; a pair of angled extensions, each angled extension connecting a respective contact tab to its respective conductive strap, the angled extensions spanning between the plane of the conductive strap and the plane of the contact tab, the angled extensions being arcuate and separated by the separation gap; a notched portion defined in the conductive strap and continuous with the separation gap; the cutout portion and the separation gap are surrounded by the conductive strap; the cutout portion includes an arcuate slot at least partially surrounding the contact tab. Conductive strap.

2. the cutout portion includes a first cutout portion and a second cutout portion; the first cutout portion, the separation gap, and the second cutout portion are continuous. The conductive strap of claim 1 .

3. The conductive strap of claim 1 , wherein each contact tab is asymmetric.

4. The conductive strap of claim 1 , wherein each contact tab is shaped as a truncated semicircle.

5. The conductive strap of claim 1 , wherein the enclosed area is generally circular and the diameter of the enclosed area is in the range of 12 millimeters to 17 millimeters.

6. Each contact tab is connected to its corresponding conductive strap by a connecting extension; the angle between the connection extensions of each contact tab ranges between 70 degrees and 90 degrees; The conductive strap of claim 2 .

7. The conductive strap of claim 6 , wherein the separation gap and the second notched portion are included in an angle measurement.

8. the conductive strap plane is parallel to the contact tab plane, and the contact tab plane is offset from the conductive strap by a distance in the range of 0.5 millimeters to 2.0 millimeters; The conductive strap of claim 1 .

9. The conductive strap of claim 2 , wherein the arcuate slot, the first cutout portion, and the second cutout portion are continuous.

10. a route from one contact depression on the first contact tab, around the second cutout portion, to one contact depression on the second contact tab; The root distance is in the range of 16.5 mm to 20 mm. The conductive strap of claim 2 .

11. The conductive strap of claim 2 , wherein the width between the edge of the conductive strap and the outermost edge of the first cutout portion ranges from 4 millimeters to 10.5 millimeters.

12. 1. A conductive strap for a battery pack, comprising: The conductive strap defines a conductive strap plane, the conductive strap having: a plurality of battery contacts; a plurality of angled extensions; each battery contact portion has at least one contact tab, each contact tab including at least one contact recess, each pair of contact tabs defining a contact tab plane, said contact tab plane being offset from said conductive strap plane; each angled extension connects a respective contact tab to the conductive strap, each angled extension straddling a plane of the conductive strap and a plane of the contact tab, each angled extension being arcuate; the subset of battery contacts includes more than one contact tab; At least one battery contact portion includes a single contact tab; Conductive strap.

13. 13. The conductive strap of claim 12, wherein the battery contact portions having a single contact tab have a different arrangement than the subset of battery contact portions having more than one contact tab.

14. The conductive strap of claim 13 , wherein the subset of the battery contact portions includes all but one of the battery contact portions.

15. 13. The conductive strap of claim 12, wherein the subset of the battery contact portions having more than one contact tab further includes a separation gap defined in the conductive strap between the respective contact tabs of each pair of the contact tabs, the more than one contact tabs being separated from adjacent contact tabs by the separation gap.

16. The conductive strap of claim 15 , further comprising a notched portion defined in the conductive strap and contiguous with the separation gap.

17. The conductive strap of claim 12 , wherein each contact tab is shaped as a truncated semicircle.

18. 1. A method for installing a conductive strap onto a battery cell, comprising: aligning a pair of contact tabs of the conductive strap with an edge of the battery cell, the pair of contact tabs being offset from the conductive strap and at least partially surrounded by an arcuate slot; pressing a weld header against the pair of contact tabs of the conductive strap toward the end of the battery cell; moving the contact tabs independently relative to the remainder of the conductive strap, thereby deflecting a connection extension piece corresponding to each contact tab so as to engage the end of the battery cell with a contact recess of the contact tab, the connection extension piece being arc-shaped and separated from adjacent connection extension pieces; and resistance welding the pair of contact tabs to the ends of the battery cells at the contact recesses. method.

Images