[001] This disclosure relates generally to batteries, and more particularly to battery packs for an electric vehicles.

BACKGROUND
[002] Electric vehicles have been around for some decades now and have found greater popularity amongst masses lately. Design, manufacturing, and usage of the batteries of the electric vehicles are supposed to adhere to functional safety requirement imposed by various national and international standards, such as ISO 26262. Further, there are ethical considerations with respect to providing safe and effective battery packs. However, there are multiple challenges with respect to adhering to the above standards and the ethical considerations. The battery pack design must comply with safety goals and load demand, as the load determines the configuration of the battery pack. Further, the battery pack designs must take into consideration reducing the heat losses.
[003] At the time of the designing and manufacturing of the battery packs, the efficiency of the battery packs is important. The cells are fundamental constituents of the battery pack, and therefore, parameters like internal resistance, contact resistance at welding, cell sorting, geometry of cell arrangement, safety goals fulfilment, and reliability of the pack at various loading condition must be take into consideration. The cell sorting parameters such as internal resistance of the cells and voltage at the time of welding is critical to the design of the battery pack. Further, the contact resistance when the cells are welded with a bus must be taken into account. The contact resistance should be near to absolute zero for an effective battery pack. The geometry of arrangement of the cells in the battery pack to provide the required design voltage is a key element of the battery pack development. The guiding parameters are the cell dimensions and the gap between two adjacent cells, so that there is minimum heat transfer from one cell to another.

SUMMARY
[004] In one embodiment, a battery pack is disclosed. The battery pack may include a cell casing that may defined a plurality of cell holders. The battery pack may further include a plurality of cells positioned within the cell casing. Each cell may be positioned within a respective cell holder of the plurality of cell holders. Further, each cell may be configured with a predetermined voltage and charge rating. The plurality of cell holders may be configured to create a predetermined gap between any two adjacent cells. A plurality of cell sets of the plurality of cells may be electrically inter-coupled in series, to create a plurality of series-connected cell sets. The plurality of series-connected cell sets may be electrically inter-coupled in parallel.
[005] In another embodiment, a method of assembling a battery pack is disclosed. The method may include providing a cell casing. The cell casing may define a plurality of cell holders. The method may further include positioning, within each of the plurality of cell holders, a cell of a plurality of cells. Each cell may be configured with a predetermined voltage and charge rating. The plurality of cell holders may be configured to create a predetermined gap between any two adjacent cells. The method may further include electrically inter-coupling, in series, a plurality of cell sets, to create a plurality of series-connected cell sets. The method may further include electrically inter-coupling, in parallel, the plurality of series-connected cell sets.
[006] In yet another embodiment, another method of assembling a battery pack is disclosed. The method may include providing a cell casing that may define a plurality of cell holders. The method may further include positioning, within each of the plurality of cell holders, a cell of a plurality of cells. Each cell may be configured with a predetermined voltage and charge rating. The positioning may include positioning the plurality of cells within the cell casing along a first row, a second row, a third row, a fourth row, and fifth row. Each of the first row, the second row, the third row, and the fourth row may include three series-connected cell sets. Further, the fifth row may include four series-connected cell sets. Each of the series-connected cell sets may include three cells. The method may further include electrically inter-coupling, in series, a plurality of cell sets of the plurality of cells, to create a plurality of series-connected cell sets. The method may further include electrically inter-coupling, in parallel, the plurality of series-connected cell sets.
[007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS
[008] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, explain the disclosed principles.
[009] FIGs. 1A-1C illustrate an isometric view, a first top view, and a second top view, respectively of a battery pack battery pack, in accordance with some embodiments of the present disclosure.
[010] FIG. 1D illustrates an isometric view of a cell casing, in accordance with some embodiments.
[011] FIGs. 1E-1G illustrate a top view, a front view, and a side view, respectively, of a cell, in accordance with some embodiments.
[012] FIGs. 2A-2E illustrate a perspective view, a front view, a side view, a top view, and a sectional view (along A-A of FIG. 2B) of a L-shaped bus are illustrated, in accordance with some embodiments of the present disclosure.
[013] FIGs. 3A-3C illustrate a perspective view, a top view, and a side view of an Omega-shaped bus, in accordance with some embodiments.
[014] FIGs. 4A-4B illustrate a perspective view, a front view, and a side view of an electric connector, in accordance with some embodiments of the present disclosure.
[015] FIG. 5 illustrates a welding region, in accordance with some embodiments.
[016] FIG. 6 is a flowchart of a method of assembling the battery pack, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION
[017] Exemplary embodiments are described with reference to the accompanying drawings. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the spirit and scope of the disclosed embodiments. It is intended that the following detailed description be considered as exemplary only, with the true scope and spirit being indicated by the following claims. Additional illustrative embodiments are listed below.
[018] The present disclosure provides a battery pack that includes a plurality of cells arranged in multiple rows. For example, the battery pack my include 48 prismatic cells, each having a cell capacity of 23 Ampere hour (Ah) and 2.7 Volts (V) cell voltage rating. The cells are inserted in cell holders of a cell casing, that is made of polypropylene with a temperature resistance of 150 °C. The cell holders maintain a gap of 2 millimeters (mm) in between the adjacent cells. The air between the cells works as a layer of thermal insulation resisting the heat transfer while the battery operates. The lithium titanate cells have a maximum temperature raise of 10 °C while charging at 3 °C and around 2 °C while discharging. The cells are welded onto a combination of different types of buses that may be L-shaped buses or Omega-shaped buses. The buses are made of 1100 grade Aluminium coated in Zinc. Further, the 1.6 mm thick L-shaped bus or the Omega-shaped bus acts as a bridge between the adjacent of cells arranged in series. The cells are arranged in a configuration of 3 parallel and 16 series.
[019] Further, the cells in the cell casing may experience vibration. The vibration is overcome by providing inserts between cells, that hinder the movement or misalignment of the cells. For the ease of manufacturing the cells are welded a very specific configuration. For example, 9 cells are welded together in one configuration and 12 cells are welded in another configuration. In a battery pack consisting of 48 cells, four 9 cell configurations and one 12 cell configuration is used. Electric connectors, such as brass plates, are used to connect the cells in series using fasteners, to form the battery pack. Therefore, in the battery pack comprising 48 cells, 96 weld spots are formed for welding the cell terminals with the electric buses.
[020] The penetration of the weld plays an important part to the configuration. A laser power of 1100 Watts with a wobble amplitude of 0.5 mm at a frequency of 600Hz and weld speed of 30mm/sec may be applied. Weld depths (L1 and L2) of 1.8 mm and 1.7 mm, respectively, are used. Further, weld thickness (L4 and L3) of 1.5 mm and 1.3 mm, respectively, is used.
[021] Referring to FIGs. 1A-1C, an isometric view, a first top view, and a second top view, respectively of a battery pack battery pack 100 are illustrated, in accordance with some embodiments of the present disclosure. The battery pack 100 may include a cell casing 102. The cell casing 102 may be manufactured from a material selected from a metal, a polymer, a plastic, or a composite material. In one example implementation, the cell casing 102 may be manufactured from a polypropylene material. As can be seen in FIGs. 1A, the cell casing 102 may have an open top. Further, the cell casing 102 may have a base, and multiple walls defining the periphery of the cell casing 102. In some embodiment, as can be seen in FIGs. 1A-1B, the cell casing 102 may include a plurality of cell holders. In one example, the cell holders may be projections on the base of the cell casing 102. In another example, the cell holders may be in form of walls (same length as the walls of cell casing 102 defining the periphery of the cell casing 102). In such examples, the cell holders may divide the cell casing 102 in a plurality of sections. An isometric view of the cell casing 102 is illustrated in FIG. 1D.
[022] The battery pack 100 may further include a plurality of cells 104. The plurality of cells 104 may be configured to be positioned within the cell casing, such that each cell is positioned within a respective cell holder of the plurality of cell holders. In one example, as shown in FIGs. 1A-1C, the battery pack 100 may include forty eight cells – 104-1, 104B-2, 104-3, … and so on (as such, the plurality of cells, collectively may have been referred to as cells 104, or individually as cell 104).
[023] As will be appreciated, when the battery pack 100 is implemented in an electric vehicle, during the operation of the electric vehicle, the cells 104 in the cell casing 102 may experience vibration. In order to overcome the vibration, inserts may be provided between adjacent cells 104, that hinder the movement or misalignment of the cells.
[024] By way of an example, each of the plurality of cells 104 may be a prismatic cell. Each cell 104 may be configured with a predetermined voltage and charge rating. Further, by way of an example, each of the plurality of cells 104 may be configured with 2.7 Volts rating and 23 Ampere hour charge rating.
[025] In some embodiments, each of the cells 104 may be a lithium titanate cell. In order to assemble the battery pack 100, the cells 104 may be positioned within the respective cell holders of the battery pack 100. Once assembled, during operation, the cells 104 may undergo a (maximum) temperature raise of around 10? C while charging, and around 2? C while discharging. To this end, the plurality of cell holders may be configured to create a predetermined gap between any two adjacent cells. For example, this predetermined gap between any two adjacent cells may be 2 millimeters (mm). As a result of the gap, air between the cells 104 may work as a layer of thermal insulation resisting the heat transfer while the battery operates.
[026] In some embodiments, a plurality of cell sets may be electrically inter-coupled in series, to create a plurality of series-connected cell sets 106. As shown in FIG. 1B, the plurality of cells 104 may be divided into the plurality of cell sets 106. In the example embodiment shown in FIG. 1B, the plurality of cell sets 106 may include sixteen cell sets, i.e. cell sets 106-1, a set 106-2, … 106-16 (as such, the plurality of cell sets, collectively may have been referred to as cell sets 106, or individually as cell set 106). The sixteen cell sets are electrically inter-coupled in series in series. Further, in the above example embodiment, each cell set of the plurality of cell sets 106 may include three cells 104. For example, as shown in FIG. 1B, the cell set 106-1 includes three cells 104-1, 104-2, 104-3. Configuration of the cell 104 is shown in FIGs. 1D-1F
[027] Referring now to FIGs. 1E-1G, a top view, a front view, and a side view of the cell 104 is illustrated, in accordance with some embodiments. As shown, the cell 104 includes a positive terminal and a negative terminal (upon which a weld spot may be formed to electrically couple the cell 104 with other cells). By way of an example, the cell 104 may be prismatic having a width of 115.5 mm, a thickness of 22 mm, and a height of 105.5 mm.
[028] It should be noted that the cells 104 within each cell set 106 may be electrically intercoupled in parallel. For example, as shown in FIG. 1B, the cells 104-1, 104-2, 104-3 of the cells set 106-1 are electrically intercoupled in parallel. As will be appreciated by those skilled in the art, each cell 104 may include a positive terminal and a negative terminal. Therefore, for the cell set 106-1, the positive terminals of the cells 104-1, 104-2, 104-3 may be electrically intercoupled, and in the same way, the negative terminals of the cells 104-1, 104-2, 104-3 may be electrically intercoupled. In some embodiments, as shown in FIG. 1C, the positive terminals of the cells 104-1, 104-2, 104-3 may be electrically intercoupled using a first electric bus 108. The first electric bus may be a metallic component that when connected with the cells in a desired configuration, the design voltage of operation is achieved. Further, in such embodiments, the first electric bus 108 may be a L-shaped bus 108, as can be seen in FIGs. 1A. The L-shaped bus 108 is further explained in conjunction with FIGs. 2A-2E.
[029] Referring now to FIGs. 2A-2E, a perspective view, a front view, a side view, a top view, and a sectional view (along A-A of FIG. 2B) of the L-shaped bus 108 are illustrated, in accordance with some embodiments of the present disclosure. The L-shaped bus 108 includes a first face 108A and a second face 108B. The first face 108A and the second face 108B may be inclined at an angle of 90 degrees (with a tolerance of +0.2 to -0.2 degrees) to each other. Further, a length of the L-shaped bus 10 may be 61 millimeters (mm). A height of the first face 108A may be 30 mm, and a height of the second face 108B may be 25 mm.
[030] By way of one example, the positive terminals of the cells 104-1, 104-2, 104-3 may be electrically intercoupled (in parallel) via the first face 108A of the L-shaped bus 108, as shown in FIG. 1A and 1C. As such, the second face 108B of the L-shaped bus 108 may be oriented vertically. In order to electrically intercouple the positive terminals of the cells 104-1, 104-2, 104-3 via the first face 108A of the L-shaped bus 108, the first face 108A of the L-shaped bus 108 may include weld slots 204. As shown in FIGs. 2A-2B, the first face 108A of the L-shaped bus 108 may include three weld slots 204. It should be noted that the first face 108A of the L-shaped bus 108 may be welded to the three cells 104 of each cell set 106 via the three weld slots 204. In other words, each cell 104 of the cell set 106 may be welded to the first face 108A of the L-shaped bus 108 through a respective weld slot of the three weld slots 204.
[031] By way of an example, as shown in FIG. 2A, each of the weld slots 204 may include a depression 204A and a hole 204B. The hole 204B and the depression 204A may allow for an easy and an effective weld spot to form between the second face 108B and the cells of the cell sets. In particular, the hole 204B and the depression 204A may allow for a right amount of welding material to be deposited and to a sufficient depth to provide a strong and stable
[032] In some embodiments, as shown in FIGs. 2A-2E, the diameter of the depression 204A of each weld slot 204 may be 8 mm, and the diameter of the hole 204B of each weld slot 204 may be 3.5 mm. A distance between two adjacent weld slots 204 may be 24 mm. As shown in FIG. 2E, a thickness of the depression region of the weld slot 204 may be 0.5 mm.
[033] As shown in FIG. 2D, the second face 108B may include one or more fastening holes 202. For example, the second face 108B may include two fastening holes 202. The diameter of each of the two fastening holes 202 may be 8.2 mm, and a distance between the two fastening holes 202 may be 25 mm.
[034] In some embodiments, the welding may be performed at a laser power of 1100 Watts, with a wobble amplitude of 0.5 mm, at a frequency of Hertz (600Hz). Further, the welding may be performed at a welding speed of 30 mm/second. The weld slots and the process of welding is further explained later in conjunction with FIG. 5
[035] Referring back to FIGs. 1A-1C, the plurality of cell sets 106 may be electrically inter-coupled in series, to create a plurality of series-connected cell sets. In reference with FIG. 1C, the cells of the cell set 106-1 may be electrically inter-coupled in series with the cells of the cell set 106-2. In other words, the three cells of the cell set 106-1 and the three cells of the cell set 106-2 may be electrically inter-coupled. In some embodiments, as shown in FIG. 1B, the three cells of the cell set 106-1 and the three cells of the cell set 106-2 may electrically inter-coupled using a second electrical bus 110. The second electric bus may be one an Omega-shaped bus 110. The material of this second electric bus 110 (i.e. the Omega-shaped bus 110) may be 1100 grade Aluminium coated with Zinc, and its thickness may be 1.6 mm. As will be appreciated, by way of the shape of the Omega-shaped bus 110, the Omega-shaped bus 110 is able to electrically inter-couple the three cells of the cell set 106-1 and the three cells of the cell set 106-2. As such, the cells of the cell set 106-1 and the cells of the cell set 106-2 are electrically inter-coupled in series. In this way, the cells of all the sixteen cells sets 106 are electrically inter-coupled in series, for example, using eight L-shaped buses 108 and eleven Omega-shaped buses 110, to create sixteen series-connected cell sets 106. The Omega-shaped bus 110 is further explained in conjunction with FIGs. 3A-3C.
[036] Referring now to FIGs. 3A-3C, a perspective view, a top view, and a side view of the Omega-shaped bus 110 are illustrated, in accordance with some embodiments. As can be seen in FIG. 3A, the Omega-shaped bus 110 includes a first face 110A and a second face 110B. Further, the Omega-shaped bus 110 includes a bump between the first face 110A and the second face 110B. It should be noted that the first face 110A and the second face 110B may be electrically attached to the (three) cells of the one of the cells sets another cell set positioned next to it. The Omega-shaped bus 110 further includes three weld slots 302 (similar to the weld slots 204) on each of the first face 110A and the second face 110B. The first face 110A and the second face 110B may be electrically attached to the (three) cells of the respective cell sets be welding them through these weld slots 302. It should be noted that each of the weld slots 302, as shown in FIG. 3A, may provide a hole 302B and a depression 302A. The hole 302B and a depression 302A may allow for an easy and an effective weld spot to form between the first face 110A or the second face 110B and the cells of the cell sets. In particular, the hole 302B and the depression 302A may allow for a right amount of welding material to be deposited and to a sufficient depth to provide a strong and stable
[037] As shown in FIGs. 3B-3C, in some embodiments, the length of the Omega-shaped bus 110 may be 61 mm, and length of each of the first face 110A and the second face 110B may be 19.35 mm. the length of the bump may be 18 mm. a distance between any adjacent two weld slots 302 may be 24 mm. Further, the diameter of the depression 302A of each weld slot 302 may be 8 mm, and the diameter of the hole 302B of each weld slot 302 may be 3.5 mm. A thickness of the depression region of the weld slot 302 may be 0.5 mm.
[038] Referring back to FIG. 1C, the sixteen cells sets 106 are arranged in five rows, such that each of a first row, a second row, a third row, and fourth row (adjacent rows) include three cell sets each, and a fifth row includes 4 cell sets. As such, each of the first, second, third, and fourth row constitutes a 9 cell configuration, and the fifth row constitutes a 12 cell configuration.
[039] The three cell sets of each of the first row, the second row, the third row, and the fourth row are electrically inter-coupled using two Omega-shaped buses 110.
[040] In some embodiments, in order to electrically inter-couple the three cell sets of each of the first row, the second row, the third row, the fourth row, and the fifth row, electric connectors 112 may be used. For example, the electric connectors 112 may be brass plate. For example, two adjacent lying cell sets associated with the first row and the second row are electrically inter-coupled via respective L-shaped buses 108 and an electric connector 112-1. Similarly, two adjacent lying cell sets associated with the second row and the third row are electrically inter-coupled via respective L-shaped buses 108 using an electric connector 112-2. Further, two adjacent lying cell sets associated with the third row and the fourth row are electrically inter-coupled using via respective L-shaped buses 108, using an electric connector 112-3. Further, two adjacent lying cell sets associated with the fourth row and the fifth row are electrically inter-coupled using via respective L-shaped buses 108, using a electric connector 112-4. The electric connector 112 (hereinafter, collectively or individually referred using the reference numeral 112) is further explained in conjunction with FIGs. 4A-4C.
[041] Referring now to FIGs. 4A-4B, a perspective view, a front view, and a side view of the electric connector 112 is illustrated, in accordance with some embodiments of the present disclosure. The electric connector 112 includes a flat plate and one or more fastening holes 402. The fastening holes 402 may be used to fasten the electric connector 112 with two adjacent L-shaped buses 108 to electrically inter-couple the cell sets in adjacent rows, as explained above. In some embodiments, the electric connector 112 may be fastened with the two adjacent L-shaped buses 108 using fasteners (e.g. fastener in the direction F as shown in FIGs. 1A and 4A) such as nut-bolts, screws, rivets, etc. Further, upon fastening, the fasteners may be welded to the electric connector 112 and the each of the two adjacent L-shaped buses 108 to secure the connection. For example, the electric connector 112 may include four fastening holes 402. Two of these four fastening holes 402 may be used to fasten the electric connector 112 with a first L-shaped bus 108 and the rest two of the four fastening holes 402 may be used to fasten the electric connector 112 with a second L-shaped bus 108.
[042] By way of an example, the material of the electric connector 112 may be brass. A length of the electric connector 112, as shown in FIG. 4C, may be 114 mm. a distance between two adjacent holes fastening holes 402 may be 25 mm. A diameter of each of the four fastening holes 402 may be 8 mm.
[043] Referring now to FIG. 5, a welding region 500 corresponding to the weld slots 204 and 302 is illustrated, in accordance with some embodiments. As mentioned above, the welding may be performed to electrically couple the cells 104 with the L-shaped bus 108 or the Omega-shaped bus 110, via the weld slots 204 or 302, respectively. The welding may be performed at a welding speed of 30 mm/second. As shown in FIG. 5, the welding may be performed at a first depth (L1) of 1.8 mm and second depth (L2) of 1.7 mm. Further, the welding thickness may be a first thickness (L3) of 1.5 mm or a second thickness (L4) of 1.3 mm.
[044] Referring now to FIG. 6, a flowchart of a method 600 of assembling the battery pack 100 is illustrated, in accordance with some embodiments of the present disclosure. As step 602, the cell casing 102 may be provided. The cell casing 102 may defined the plurality of cell holders. At step 604, within each of the plurality of cell holders, a cell of a plurality of cells 104 may be positioned. Each cell may be configured with a predetermined voltage and charge rating, for example, 2.7 Volts rating and 23 Ampere hour charge rating. It should be noted that the plurality of cell holders may be configured to create a predetermined gap between any two adjacent cells.
[045] At step 606, the plurality of cell sets 106 may be electrically inter-coupled, in series, to create a plurality of series-connected cell sets. At step 608, the plurality of series-connected cell sets may be electrically inter-coupled, in parallel. The plurality of cell sets may be electrically inter-coupled in series, by welding, using at least one electric bus, for example, the L-shaped bus 108 or the Omega-shaped bus 110. The plurality of series-connected cell sets may be electrically inter-coupled in parallel, by welding, using at least one electric connector 112. For example, the electric connector 112 may be a brass plate. The welding may be performed at a laser power of 1100 Watts, with a wobble amplitude of 0.5 mm, at a frequency of Hertz (600Hz). Further, the welding may be performed at a welding speed of 30 mm/second.
[046] Further, a method 700 of assembling the battery pack 100 is disclosed. As step 702, the cell casing 102 may be provided. The cell casing 102 may define the plurality of cell holders. At step 704, a cell of a plurality of cells may be positioned, within each of the plurality of cell holders. Each cell may be configured with a predetermined voltage and charge rating. The positioning may include positioning the plurality of cells 104 within the cell casing 102 along a first row, a second row, a third row, a fourth row, and fifth row. Each of the first row, the second row, the third row, and the fourth row may include three series-connected cell sets. Further, the fifth row may include four series-connected cell sets. Each of the series-connected cell sets may include three cells.
[047] At step 706, the plurality of cell sets may be electrically inter-coupling, in series, to create the plurality of series-connected cell sets. At step 708, the plurality of series-connected cell sets may be electrically inter-coupled, in parallel.
[048] The above disclosure provides for an improved battery pack and methods of assembling battery packs. For example, the battery pack includes three series and sixteen parallel configuration of cells in the battery pack. The geometry of the said configuration provides for a compact yet highly improvised configuration of cells of the battery pack. Further, by using Omega-shaped buses, L-shaped buses, and electric connectors (brass plates), the required configuration and electrical connections are obtained. This further provides for using easy and effective assembling of the batter pack. Moreover, by using Laser-based welding, as per the above welding parameters, of the prismatic cells, strong and stable electrical connections can be obtained.
[049] It is intended that the disclosure and examples be considered as exemplary only, with a true scope and spirit of disclosed embodiments being indicated by the following claims.

We Claim:

1. A battery pack comprising:
a cell casing defining:
a plurality of cell holders; and
a plurality of cells positioned within the cell casing, each cell positioned within a respective cell holder of the plurality of cell holders, and each cell being configured with a predetermined voltage and charge rating,
wherein the plurality of cell holders is configured to create a predetermined gap between any two adjacent cells,
wherein a plurality of cell sets of the plurality of cells is electrically inter-coupled in series, to create a plurality of series-connected cell sets,
wherein the plurality of series-connected cell sets is electrically inter-coupled in parallel.

2. The battery pack as claimed in claim 1,
wherein the plurality of cell sets is electrically inter-coupled in series, by welding, using at least one electric bus, and
wherein the plurality of series-connected cell sets is electrically inter-coupled in parallel, by welding, using at least one electric connector,
wherein the welding is performed at a laser power of 1100 Watts, with a wobble amplitude of 0.5 mm, at a frequency of Hertz (600Hz), and
wherein the welding is performed at a welding speed of 30 mm/second.

3. The battery pack as claimed in claim 2,
wherein the at least one electric bus is one of a L-shaped bus and an Omega-shaped bus, and
wherein a material of the at least one electric bus is 1100 grade Aluminium coated with Zinc, and
wherein a thickness of the at least one electric bus is 1.6 mm.

4. The battery pack as claimed in claim 2,
wherein each cell set of the plurality of cell sets comprises three cells, and
wherein the plurality of series-connected cell sets is sixteen series-connected cell sets.

5. The battery pack as claimed in claim 1,
wherein each of the plurality of cells is a prismatic cell, and
wherein each of the plurality of cells is configured with 2.7 Volts rating and 23 Ampere hour charge rating.

6. The battery pack as claimed in claim 1,
wherein the cell casing and the plurality of cell holders are made of a polypropylene material and
wherein the predetermined gap between any two adjacent cells is 2 milli-meters (mm).

7. The battery pack as claimed in claim 1,
wherein the cell casing is L-shaped,
wherein the plurality of cells is positioned within the cell casing along a first row, a second row, a third row, and a fourth row,
wherein each of the first row, the second row, and the third row comprises three series-connected cell sets,
wherein the fourth row comprises four series-connected cell sets, and
and wherein each of the series-connected cell sets comprises three cells.

8. A method of assembling a battery pack, the method comprising:
providing a cell casing, the cell casing defining:
a plurality of cell holders;
positioning, within each of the plurality of cell holders, a cell of a plurality of cells, wherein each cell is configured with a predetermined voltage and charge rating,
wherein the plurality of cell holders is configured to create a predetermined gap between any two adjacent cells,
electrically inter-coupling, in series, a plurality of cell sets, to create a plurality of series-connected cell sets; and
electrically inter-coupling, in parallel, the plurality of series-connected cell sets.

9. The method as claimed in claim 8,
wherein the plurality of cell sets of the plurality of cells is electrically inter-coupled in series, by welding, using at least one electric bus, and
wherein the plurality of series-connected cell sets is electrically inter-coupled in parallel, by welding, using at least one electric connector,
wherein the welding is performed at a laser power of 1100 Watts, with a wobble amplitude of 0.5 mm, at a frequency of Hertz (600Hz), and
wherein the welding is performed at a welding speed of 30 mm/second.

10. A method of assembling a battery pack, the method comprising:
providing a cell casing, the cell casing defining:
a plurality of cell holders;
positioning, within each of the plurality of cell holders, a cell of a plurality of cells, wherein each cell is configured with a predetermined voltage and charge rating, wherein the positioning comprises:
positioning the plurality of cells within the cell casing along a first row, a second row, a third row, a fourth row, and fifth row,
wherein each of the first row, the second row, the third row, and the fourth row comprises three series-connected cell sets,
wherein the fifth row comprises four series-connected cell sets, and
and wherein each of the series-connected cell sets comprises three cells;
electrically inter-coupling, in series, a plurality of cell sets of the plurality of cells, to create a plurality of series-connected cell sets; and
electrically inter-coupling, in parallel, the plurality of series-connected cell sets.