Patent ID: 12230824

DETAILED DESCRIPTION

Referring toFIGS.1through8, in an exemplary embodiment, a first battery pack10includes a housing12. The housing12includes an upper housing/portion14and a lower housing/portion16. The upper housing14includes a mechanical interface18for mating and coupling with a power tool200having a corresponding mechanical interface202. The battery pack mechanical interface18includes a pair of rails20and a pair of grooves22. The grooves22receive a corresponding pair of rails204of the power tool200. The battery pack mechanical interface18also includes a plurality of slots24. The plurality of slots24are configured to receive a corresponding plurality (set) of power tool terminals206that mechanically and electrically mate with a corresponding plurality (set) of battery pack terminals26, The plurality slots24define a plurality of parallel planes. The battery pack10is inserted into the power tool200in a direction parallel with the plurality of slots24and the plurality of parallel planes the insertion direction. The insertion direction is denoted by arrow A.

The first battery pack10has a width Y in a dimension perpendicular to the planes defined by the slots.

In order to connect a plurality of battery cells in a battery pack, a plurality of battery straps are applied to a cell holder. Applying these straps manually is a time consuming process and may lead to straps being applied to the wrong locations. This can be a safety concern. Referring toFIGS.9through11, an exemplary embodiment is illustrated in which a plurality (set) of battery cell straps30are insert molded in a cell holder32, This eliminates the risk of incorrect straps being place in incorrect locations, saves time in assembly and provides a product with fewer contaminants. As illustrated inFIG.11, the cell holder32may include two subassemblies34,36(A and B). To generate each subassembly34,36, the set of battery straps30are placed in a mold. Plastic (or other suitable material) is injection molded into the mold around the set of battery straps30. The two cell holder subassemblies34,36are then assembled with a plurality of battery cells38resulting in a cell holder/cell subassembly32. The straps30may then be welded to the battery cells38.

Referring toFIGS.12,13,14A,14B,14C, and140, there is illustrated an exemplary battery terminal26. As illustrated, contact points of the battery terminals26are beads40that are formed by a punch instead of a bend. The tool blade (terminal)206is perpendicular to spring arms42of the battery terminal26. The springs arms42are completely independent to one another. The battery terminals26are mounted directly to a PCB44and then soldered. As such, no terminal block is needed. This configuration provides a large cross section that allows the battery terminal26to run cooler at higher current draw.

As illustrated inFIGS.14A through140, the first part of the battery terminal26that makes contact with the tool terminal206is the bead40of the battery terminal26.

FIGS.15and16illustrate a first exemplary embodiment of a core pack50of the first battery pack10, In this embodiment, the core pack50—and therefore the battery pack10includes fifteen battery cells38. The battery cells38are configured in three sets of five cells—an A set52a, a B set52band a C set52c. The five cells38in each set52a,52b,52care connected in series and the three sets52a,52b,52care connected in series—when coupled to a power tool200. Each set52a,52b,52cis referred to as 5S1P-five cells in series.

The sets of cells52a,52b,52care configured to minimize the amount of space required. Specifically, each the cells38of each set52a,52b,52care positioned relative to each other the same way but the B set52bis rotated about an axis in the center of the set that is parallel to a longitudinal axis of the battery cells38. Furthermore, the A set52aand the C set52chave the same orientation. As such, the B set52bis sandwiched between the A set52aand the C set52cto minimize the space the cells38require in a direction perpendicular to the longitudinal axis of the battery cells and in a direction parallel to the insertion direction.

In other words, each set of cells52a,52b,52cincludes three cells30adjacent to each other and aligned with their longitudinal axes in a first plane and two cells30adjacent to each other and aligned with their longitudinal axes in a second plane that is parallel to the first plane. Furthermore, adjacent sets of cells52a,52b,52care arranged such that the first plane of the first set52ais in the same plane as the second plane of the second set52band the second plane of the first set52ais in the same plane as the first plane of the second set52b.

Specifically, the first plane of the A set52ais in the same plane as the second plane of the B set52band the second plane of the A set52ais in the same plane as the first plane of the B set52b. The same is true of the B set52band the C set52c. This provides a particularly compact core pack50—and battery pack10—in the insertion direction.

Referring toFIGS.18and19, another exemplary embodiment of a core pack60is illustrated. In this embodiment, there are still three sets of battery cells62a,62b,62cand the three sets62a,62b,62care connected in series, however each set62a,62b,62cincludes ten battery cells30, In this embodiment, in each set of battery cells62a,62b,62cthere are five subsets of two battery cells30wherein the two battery cells30of each subset are connected in parallel and the five subsets are connected in series. This results in the same voltage as the previous embodiment but with twice the capacity assuming the same battery cells in each embodiment. In this embodiment, each set62a,62b,62cis referred to as 5S2P five subsets in series with each subset having two battery cells30in parallel.

Again, the sets of battery cells62a,62b,62care arranged to minimize the space in the dimension in the insertion direction, similar to the previous embodiment.

Referring toFIGS.20through22, there is illustrated an exemplary embodiment for distributing and removing water that gets into the battery pack housing12, As illustrated inFIGS.20and21, a plurality of battery terminals26are attached to a printed circuit board44, The printed circuit board44includes a hole66located within a footprint of the terminal26. This would allow any trapped water to pass through the PCB44down onto the cell holder68,FIG.22illustrates a path—indicated by the arrows—the water would take after it passes through the PCB44. The battery pack10would include a cell holder68having a top or cap70having slanted surfaces72. After the water passes through the PCB44it would run down the slanted surfaces72of the cell holder cap70. The water would then flow down to interior sides of the pack housing12and then out of drain holes74in a bottom wall76of the battery pack housing12.

Referring toFIGS.23through28, an exemplary embodiment of a second battery pack110is illustrated. The second battery pack110includes a mechanical interface118virtually identical to the mechanical interface18of the first battery pack10. As such, the second battery pack110will be able to mate with the same power tools200as the first battery pack10—unless the manufacture desires to prevent the second battery pack10from mating with tools200that the first battery pack10is intended to mate (or vice versa) in which case the mechanical interface18/118of one or the other of the battery packs10/110may include some type of lockout. As noted above, the second battery pack100includes a plurality of slots124to receive the power tool terminals206. These slots124define a plurality of parallel planes. The second battery pack110has a width Z in a dimension perpendicular to the planes defined by the slots124. This width Z is greater than the width Y of the first battery pack10. Yet due to both battery packs10/110having the same mechanical interface18/118, both battery packs10/110are capable of mating and operating with the same power tools200.

As such, there may be a power tool system including at least one power tool200having a plurality of terminals206, a first battery pack10having a mechanical interface18for mating with the at least one power tool200, the mechanical interface18of the first battery pack10including a plurality of slots24for receiving the plurality of power tool terminals206, the plurality of slots24of the first battery pack10defining a plurality of parallel planes, the first battery pack10having a housing12, the first battery pack housing12having a width dimension in a direction perpendicular to the planes defined by the plurality of slots24, and a second battery pack110having a mechanical interface118for mating with the at least one power tool200, the mechanical interface118of the second battery pack110including a plurality of slots124for receiving the plurality of power tool terminals206, the plurality of slots124of the second battery pack110defining a plurality of parallel planes, the second battery pack110having a housing112, the second battery pack housing112having a width dimension Z in a direction perpendicular to the planes defined by the plurality of slots124, wherein the width dimension Z of the second battery pack100is greater than the width dimension Y of the first battery pack100. In one embodiment, the width dimension Z of the second battery pack100is at least 1.5 times the width dimension Y of the first battery pack10.

FIGS.29,30and31illustrate a third exemplary battery pack300having a modular core pack360. In this exemplary embodiment, the third battery pack300includes a plurality of core pack modules360a,360b,360c. Each module360a,360b,360cincludes a plurality of battery cells30held in relative position to each other by a cell holder332.

In an exemplary embodiment, the second battery pack300is a 60-volt rated battery pack having a relatively high capacity (Amp-hour rating). To achieve this voltage and capacity, the battery pack300includes forty-five battery cells30.

When using so many battery cells in a battery pack300is not unheard of to have one or more of the battery cells30fail or become unfit during the manufacture and assembly of the cells30and/or the pack300. In this instance, if all forty-five cells were assembled into a single core pack and if a single cell of that single core pack were to be found unusable the entire core pack of forty-five cells would need to be thrown away—resulting in a significant waste of materials.

In order reduce waste associated with placing so many cells30into a battery pack300, a modular approach has been taken. In this approach, in this exemplary embodiment, each module360a,360b,360cincludes fifteen four-volt cells30. Each module360a,360b,360cincludes five sets of three four-volt cells30wherein the three four-volt cells30are connected in parallel and the five sets are connected in series. As such, each set of cells is rated at four volts and each module is rated at twenty (20) volts. The three modules360a,360b,360care connected in series through connections to and through the printed circuit board344resulting in a sixty (60) volt rated battery pack.

In this approach, if a cell30of a particular module360a,360b,360cis found to be unfit, then the single module can be removed wasting only fifteen cells—instead of wasting the entire forty-five cells.

As illustrated inFIG.29, the modular cores360a,360b,360care assembled in a first step. The battery cells30of the module are tested. If any of the battery cells30are found to be unfit in a particular module that particular module is thrown away. Three of the modules360a,360b,360care placed in a lower housing/portion316of the battery pack housing312. A printed circuit board344is assembled with the plurality of modules360a,360b,360cto electrically connect the modules360a,360b,360cto the battery pack terminals326. The upper housing/portion314of the battery pack housing312may then be coupled to the lower housing/portion316of the battery pack housing312to complete the battery pack300.

FIGS.32and33illustrate an exemplary power tool200that may be powered by either of the first exemplary battery pack10, the second exemplary battery pack100or the third exemplary battery pack300. In this instance, the exemplary power tool200is a lawn mower. However, other power tools may also be configured to utilize the battery packs10/100/300, for example, chain saws. The lawn mower200includes a receptacle210for receiving the battery packs10/100/300— referred to as a battery pack receptacle210.

As illustrated in detail inFIGS.34and35, the battery pack receptacle210includes a housing212defining a cavity/volume214for receiving the battery packs10/100, The battery pack receptacle210includes a mechanical interface218for mating with the battery pack mechanical interface18/118. The battery pack receptacle interface218(also referred to as a tool mechanical interface) includes a set of rails (tool rails)204that are received in the battery pack grooves22/122. The battery pack receptacle mechanical interface218also includes a slot220in a wall222of the housing212opposed to the tool rails204. The slot220has a dimension (width) X. In a preferred embodiment the slot220includes angled side walls224. The dimension X of the slot220is equal to a dimension of a bottom wall28of the housing12of the first battery pack10ofFIGS.1through8. As illustrated inFIG.7, the bottom wall28of the housing12(opposed to the portion of the housing12including the battery pack mechanical interface18) may also include angled walls45to correspond with the angled walls224of the slot220of the battery pack receptacle210. As illustrated inFIG.36, when the first battery pack10is inserted into the battery pack receptacle210and mated with the power tool200, the bottom wall28of the first battery pack10is received in the slot220. As such, the slot220assists in holding the first battery pack10in place relative to the battery pack receptacle housing210.

The second battery pack100illustrated inFIGS.23through28also includes a projected portion129of a bottom wall128of the battery pack housing112. The projected portion129has a dimension X (as illustrated inFIGS.25and26). The projected portion129may also include angled walls145to correspond with the angled wall224of the slot220of the battery pack receptacle210. As illustrated inFIG.37, when the second battery pack100is inserted into the battery pack receptacle210and mated with the power tool200, the projected portion129of the bottom wall126of the second battery pack100is received in the slot220. As such, the slot220assists in holding the second battery pack100in place relative to the battery pack receptacle housing212.

Referring toFIGS.38through42, in another exemplary embodiment, the first and second battery packs10/100may include features to address the increased weight resulting from larger and more powerful battery pack systems. To ensure that large battery packs with weights up to and over ten pounds and their mechanical interfaces18/118— particularly the rails20/120— are not susceptible to cracking, the strength of rail system is significantly increased by adding a second sloped wall46/146at the mating face of the mechanical interface18/118, In order to assist in removing the battery pack10/100from the power tool200, a spring226may be included in the power tool200to force the battery pack10/100out of the battery pack receptacle210when a latch228on the power tool200is released.

However, with the presence of the sloped wall46/146, in order for the springs226to properly operate, the springs226require a flat engagement or contact surface47/147as well as a spring receptacle48/148to trap the spring226so it stays in line with the flat engagement surface47/147. The spring receptacle48/148is preferably of a size and shape to be concentric with the spring226, Providing small circular flat surfaces on the sloped front face keeps most of the sloped front wall46/146to ensure strength while the flat portion47/147of the spring receptacle48/148provides a contact surface for the springs226. The material remaining around the spring receptacle48148serves as a guide and trap for the spring226.

As illustrated inFIG.38, in one embod8iment the battery pack10/100includes a pair of sloped walls46/146at the mating end. Each sloped wall46/146may include a spring receptacle48/148for receiving a spring226of the power tool200. The spring receptacle48/148may have a semi-cylindrical shape that is dimensioned to be concentric with the power tool spring226. The spring receptacle48/148may include a spring engagement surface47/147perpendicular to the mating direction. The spring engagement surface47/147will engage with the spring226when the battery pack10/100mates with the power tool200.

As illustrated inFIG.39, the power tool200may include a pair of springs226(only one is shown inFIG.39). Prior to engaging with the battery pack10/100the spring226is in its uncompressed state. As the battery pack10/100is inserted to the power tool200and the power tool rails204are received in the battery pack grooves22/122, the spring226will be aligned with the spring receptacle48/148.

As illustrated inFIGS.40,41, and42, when the battery pack10/100is fully mated with the power tool200the spring226will be fully compressed. The latch228on the power tool200will be received in a catch49/149of the battery pack10/100to hold the battery pack10/100fully engaged/mated with the power tool200. When the latch228is operated by a user to release the battery pack10/100, the springs226will force the battery pack10/100(at least partially) out of the battery pack receptacle210.

Numerous modifications may be made to the exemplary implementations described above. These and other implementations are within the scope of this application.