Patent Description:
It is known to use phase-change materials (PCM) for thermal management of battery packs. For example, <CIT>), <CIT>) and <CIT>), all issued to Allcell, each disclose a PCM comprising a paraffin wax for use in a pack comprising rechargeable battery cells.

An example of such a PCM material is the Phase Change Composite (PCCTM) thermal management material from AllCell Technologies LLC. <CIT> discloses manufacturing a battery module having a plurality of individual electrochemical cells by embedding cell cups in a metal foam; and inserting cell wraps into the cell cups.

It is an object of the present technology to improve current rechargeable battery packs, in particular for use in vehicles such as motorcycles, all-terrain-vehicles, snowmobiles, personal watercraft and the like.

According to the present invention, there is provided a process for constructing a battery brick according to claim <NUM>.

In some implementations, a plurality of battery modules are connected to one another, each of the plurality of battery modules comprising a plurality of the battery bricks constructed according to the invention.

In some implementations of the present technology, the plurality of battery modules are connected to one another in series.

In some implementations of the present technology, the plurality of battery bricks are connected to one another in parallel.

Some implementations comprise a plurality of bricks, each brick of the plurality of bricks comprising a phase change material block, a side of the phase change material block defining a plurality of channels, and a plurality of battery cells, each battery cell being disposed at least in part in the phase change material block; and at least one connector for electrically connecting a first one of the plurality of bricks to a second one of the plurality of bricks, the at least one connector being disposed at least partially in one of the plurality of channels.

In some implementations of the present technology, the first one of the plurality of bricks is adjacent to the second one of the plurality of bricks.

In some implementations of the present technology, the plurality of bricks are electrically connected to one another in series.

In some implementations of the present technology, the side of the phase change material block is a top side of the phase change material block.

In some implementations of the present technology, the first one of the plurality of bricks further comprises a positive current collector electrically connected to the plurality of battery cells of the first one of the plurality of bricks; the second one of the plurality of bricks further comprises a negative current collector electrically connected to the plurality of battery cells of the second one of the plurality of bricks; and the at least one connector electrically connects the positive current collector of the first one of the plurality of bricks to the negative current collector of the second one of the plurality of bricks.

In some implementations of the present technology, the battery pack further comprises at least one insulator disposed between the positive current collector of the first one of the plurality of bricks and the negative current collector of the second one of the plurality of bricks.

In some implementations of the present technology, the at least one connector is a plurality of connectors, each one of the plurality of connectors being disposed in a corresponding one of the plurality of channels.

In some implementations of the present technology, wherein for each brick of the plurality of bricks, the plurality of battery cells are arranged in an alternating pattern, wherein the plurality of battery cells are arranged in a plurality of columns, and adjacent columns of the plurality of columns are vertically staggered from one another; and at least one of the plurality of battery cells is disposed between two of the plurality of channels.

In some implementations of the present technology, the at least one connector is a metal fastener.

In some implementations, a first module group comprises at least one battery module; a second module group comprises at least one other battery module; and a manually operable interrupter assembly selectively electrically connects the first module group to the second module group in series, the interrupter assembly being adapted for opening and closing a circuit connecting the first and second module groups.

In some implementations of the present technology, a nominal voltage of each of the first and second module groups individually is less than a high voltage limit; and when the circuit is closed by the interrupter assembly, the first and second module groups are connected in series and a nominal voltage of the battery pack is greater than the high voltage limit.

In some implementations of the present technology, the high voltage limit is <NUM> Volts.

In some implementations of the present technology, when the circuit is closed by the interrupter assembly, the nominal voltage of the battery pack is <NUM> Volts; and when the circuit is opened by the interrupter assembly, the nominal voltage of each of the first and second module groups is <NUM> Volts.

In some implementations of the present technology, each module group comprises at least two battery modules connected in series.

In some implementations of the present technology, the first module group is mounted to a first location in the vehicle; the second module group is mounted to a second location in the vehicle; and the first location and the second location are spaced apart.

In some implementations of the present technology, each one of the at least one battery module and the at least one other battery module comprises a plurality of bricks, each brick comprising a phase change material block; and a plurality of battery cells disposed at least in part in the phase change material block.

Implementations of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein.

Additional and/or alternative features, aspects and advantages of implementations of the present technology will become apparent from the following description and the accompanying drawings.

With reference to <FIG>, a battery pack <NUM> includes four battery modules 12a to 12d arranged vertically, one atop the other. The four modules 12a to 12d of the pack <NUM> are mounted within the frame <NUM> of a vehicle. The modules 12a to 12d are connected in series via cables 16a to 16d, bus bars 18a and 18b, and switch assembly <NUM>, hereinafter referred to as an interrupter assembly <NUM>. The cable 16a connects the vehicle systems to a negative terminal <NUM> of the module 12a, the bus bar 18a connects the positive terminal <NUM> of the module 12a to the negative terminal <NUM> of the module 12b, the cable 16b connects the positive terminal <NUM> of the module 12b to a first terminal <NUM> of the interrupter assembly20, the cable 16c connects a second terminal <NUM> of the interrupter assembly <NUM> to the negative terminal <NUM> of the module 12c, the bus bar 18b connects the positive terminal <NUM> of the module 12c to the negative terminal <NUM> of the module 12d, and the cable 16d connects the positive terminal <NUM> of the module 12d to the vehicle systems. The vehicle systems to which the cables 16a and 16d connect can include, but are not limited to, a motor controller, a charger and a DC/DC converter.

The frame <NUM> of <FIG> is that of a three-wheeled, straddle seat road vehicle, also called a roadster. It is contemplated that the vehicle could be, inter alia, a two- or four-wheeled on-road vehicle, an off-road vehicle such as an all-terrain vehicle, a side-by-side vehicle or a snowmobile, or a waterborne vessel such as a personal watercraft or boat. It is contemplated that the pack <NUM> could include more or less modules than the four modules 12a to 12d illustrated. As will be discussed in more detail herein below, each module has a nominal voltage of 24V and the pack <NUM> has a nominal voltage of 96V. Providing two modules <NUM> in series would provide a pack with a nominal voltage of 48V. It is also contemplated that the modules 12a to 12d could be arranged other than vertically. For example, they could be arranged in two stacks of two modules 12a to 12d. It is contemplated that the modules could be mounted within a vehicle at different locations, i.e. not all adjacent one another.

The interrupter assembly <NUM> is electrically connected between the modules 12b and 12c, thereby enabling the user to manually open or close the circuit between these two modules. During operation of the vehicle, the interrupter assembly <NUM> is closed, thereby completing the circuit between the four modules 12a to 12d. When not in operation, such as during storage or maintenance, the interrupter assembly <NUM> can be opened, thereby dividing the pack <NUM> into two halves, each with a maximum voltage of <NUM> volts. According to the SAE Surface Vehicle Standard J1673 MAR2012, vehicle systems that contain a circuit operating above <NUM> volts (DC) are considered "high voltage" and surpass a high voltage limit. Similar technical standards and/or regulations exist for other regions, such as the European Union's Directive <NUM>/<NUM>/EC which pertains to circuits over <NUM> volts (DC) and the United Nations' UNECE R100 which pertains to circuits over <NUM> volts (DC). As such, a vehicle comprising the battery pack <NUM> can be rendered "low voltage" when not in use. It will be appreciated that this can be advantageous for repairs, maintenance and the like.

<FIG> shows an exploded view of an exemplary module <NUM> (i.e. the modules 12a, 12b, 12c, and 12d have a similar construction). For clarity, the module <NUM> has been inverted, that is to say its bottom side is facing up. The module <NUM> and the components thereof will hereinafter be shown in this orientation and spatial references such as "above" and "below" will, unless otherwise specified, be used in this frame of reference.

The module <NUM> comprises a plurality of battery sub-modules <NUM>, hereinafter referred to as bricks <NUM>, a fuse <NUM>, a current sensor <NUM> and a battery management system (BMS) <NUM>, all housed within a housing <NUM>. The housing <NUM> includes a housing body <NUM> which forms a cavity in which the bricks <NUM> are received. The housing <NUM> further comprises a lid <NUM> which is secured to the housing body <NUM> by a plurality of bolts <NUM>. A gasket <NUM> is positioned between the body <NUM> and the lid <NUM> in order to seal the cavity within the housing <NUM>. A communication terminal <NUM> and the negative and positive terminals <NUM> and <NUM> are provided on the housing <NUM> so as to be accessible from outside the module <NUM>. In one implementation, the body <NUM> and lid <NUM> are made of aluminum, although it is contemplated that other materials are possible.

Each brick <NUM> comprises a plurality of battery cells <NUM> surrounded by a PCM block <NUM> made of a PCM material, as will be described in further detail herein below with reference to <FIG>. During assembly, a layer of thermally conductive filler <NUM> is applied between the lid <NUM> and the plurality of bricks <NUM> so as to increase thermal conduction therebetween. In the present implementation, the thermally conductive filler <NUM> is thermal silicone (also called thermal grease) which is applied during assembly in the form of a highly viscous liquid and hardens thereafter, filling any gaps between the bricks <NUM> and the lid <NUM>. It is contemplated that various types of thermal silicone, or other highly viscous thermally conductive filler materials, could be used in the present application. The application of a suitable layer of thermal silicone during assembly can help accommodate for any variations in the dimensions of the bricks <NUM> or the housing <NUM>, thereby allowing for greater tolerances while maximizing thermal conduction between the bricks <NUM> and the housing <NUM>.

Another layer of thermal silicone <NUM> is applied between the bricks <NUM> and the wall of the body <NUM> opposite the lid <NUM>, which is similarly intended to increase thermal conduction between the bricks <NUM> and the housing <NUM>. In use, heat generated within the cells <NUM> of each brick <NUM> can be dissipated through the thermal silicone <NUM> and <NUM>, and through the metallic housing <NUM> to the environment.

It is contemplated that an active heat exchange system, such as liquid cooling or forced air, could be added to the structure illustrated herein in order to further aid in cooling the cells <NUM>. In particular, it is contemplated that the lid <NUM>, or another part of the housing <NUM>, could be provided with a liquid heat-exchanger in order to draw more heat away from the module <NUM>. Alternatively, fans could be provided proximate the lid <NUM>, or another part of the housing <NUM>, to force cooling air across the module <NUM>. The housing <NUM> could also be provided with heat-exchange fins to encourage cooling. It is also contemplated that the lid <NUM>, or other part of the housing <NUM>, could be provided with a heating element for ensuring the cells <NUM> are warm enough when operating in a cold environment.

In order to ease assembly, the cavity formed within the body <NUM> has a tapered shape and four foam wedges 68a to 68d are positioned between the lateral walls of the body <NUM> and the bricks <NUM>. The wedges 68a to 68d can be formed, inter alia, from neoprene, plastic, polystyrene foam or the like, either alone or in combination. Additional layers of thermal silicone or another thermally conductive filler could be used in place of the wedges 68a to 68d.

<FIG> shows an exploded view of an exemplary brick <NUM>. As mentioned above, the bricks <NUM> each comprise a plurality of battery cells <NUM> surrounded by the PCM block <NUM>. More particularly, each brick <NUM> comprises a total of <NUM> cells <NUM>. The cells <NUM> are cylindrical in shape with negative and positive terminals <NUM> and <NUM> at either extremity. It is contemplated that the cells <NUM> are <NUM> or <NUM> cells, although other sizes could also be used. It is contemplated that the cells <NUM> could be other than cylindrically shaped. It is also contemplated that more or less cells <NUM> could be provided per brick <NUM>. In particular, it is contemplated that between <NUM> and <NUM> cells per brick <NUM> could be provided.

The PCM block <NUM> comprises a plurality of slots <NUM>, one for each of the plurality cells <NUM>. Each slot <NUM> is sized to correspond to the length of a corresponding cell <NUM>. The thickness of the PCM block <NUM> equals that of the cells <NUM> and each slot <NUM> extends through the entire thickness of the PCM block <NUM>. When assembled, the negative and positive terminals <NUM> and <NUM> of each cell <NUM> are flush with the faces of the PCM block <NUM> at the extremities of their respective slots <NUM>. It is also contemplated that the thickness of the PCM block <NUM> could be less than the length of the cells <NUM>, such that their negative and positive terminals <NUM> and <NUM> protrude beyond the PCM block <NUM>, or that the thickness of the PCM block <NUM> could be greater than the length of the cells <NUM>.

The diameter of each slot <NUM> is sized to correspond with the diameter of the cells <NUM>. In the implementation illustrated herein, the slots <NUM> are sized so as to ensure as much contact between the cells <NUM> along their lateral sides as possible in order to maximize the transmission of heat therebetween, although other arrangements are possible. The cells <NUM> are oriented such that all of the negative terminals <NUM> are on one side of the PCM block <NUM> and all the positive terminals <NUM> are on the other. Referring to the frame of reference of <FIG>, the negative terminals <NUM> face rearward and the positive terminals <NUM> face forward.

Each brick <NUM> comprises first, second and third electrical insulators <NUM>, <NUM> and <NUM> which surround the PCM block <NUM>. When assembled, the outwardly-facing surfaces of the PCM block <NUM>, i.e. those which are not facing and/or in contact with the lateral sides of the cells <NUM>, are covered by a combination of the first, second and third electrical insulators <NUM>, <NUM> and <NUM>.

The first electrical insulator <NUM> covers the rearward-facing side of the PCM block <NUM> and comprises openings <NUM> for each negative terminal <NUM>. The first electrical insulator <NUM> also extends halfway across the top, bottom, left and right sides of the PCM block <NUM>, from the rearward-facing side towards the forward-facing side.

The second electrical insulator <NUM> is a mirror image of the first electrical insulator <NUM>. It covers the forward-facing side of the PCM block <NUM> and comprises openings <NUM> for each positive terminal <NUM>. The second electrical insulator <NUM> also extends halfway across the top, bottom, left and right sides of the PCM block <NUM>, from the forward-facing side towards the rearward-facing side. When assembled, the first and second electrical insulators each cover half of the outwardly-facing surfaces of the PCM block <NUM>.

The third electrical insulator <NUM> extends around the top, bottom, left and right faces of the PCM block <NUM>. The third electrical insulator <NUM> covers the seam between the first and second electrical insulators <NUM> and <NUM>. With the first, second and third electrical insulators in position around the PCM block <NUM> and the cells <NUM>, only the negative and positive terminals <NUM> and <NUM> are uncovered.

Each brick <NUM> further comprises a negative current collector <NUM> which is positioned adjacent and across the first electrical insulator <NUM>. The first electrical insulator <NUM> separates the negative current collector <NUM> from the rearward-facing side of the PCM block <NUM>, but the openings <NUM> allow contact between the negative current collector <NUM> and the negative terminals <NUM> of each cell <NUM>. To ensure a conductive connection, the negative current collector <NUM> and the negative terminal <NUM> of each cell <NUM> are ultrasonically welded to each other, although it is contemplated that other means of ensuring a conductive connection could be used, such as laser welding or friction welding.

Each brick <NUM> further comprises a positive current collector <NUM> which is positioned adjacent and across the second electrical insulator <NUM>. The second electrical insulator <NUM> separates the positive current collector <NUM> from the forward-facing side of the PCM block <NUM>, but the openings <NUM> allow contact between the positive current collector <NUM> and the positive terminals <NUM> of each cell <NUM>. To ensure a conductive connection, the positive current collector <NUM> and the positive terminals <NUM> of each cell are friction welded to each other, although it is contemplated that other means of ensuring a conductive connection could be used.

The negative and positive current collectors <NUM> and <NUM> are formed from sheets of conductive material, such as nickel, copper or the like, either alone or in combination. The negative and positive current collectors <NUM> and <NUM> of the current implementation each comprise a sheet of nickel welded to a sheet of copper. Both sheets are <NUM> thousandths of an inch (. <NUM>) thick, giving a total thickness of <NUM> thousandths of an inch (. The negative current collector <NUM> comprises a plurality of contact portions <NUM>, one for every opening <NUM>. When assembled, each contact portion <NUM> is positioned opposite a respective opening and a respective negative terminal <NUM>. The contact portions <NUM> each have a forked shape with two branches that are friction welded to the corresponding negative terminal <NUM> and a thinner base that connects the welded branches to the remainder of the negative current collector <NUM>.

The positive current collector <NUM> comprises a plurality of contact portions <NUM>, one for every opening <NUM>. When assembled, each contact portion <NUM> is positioned opposite a respective positive terminal <NUM>. The contact portions <NUM> each comprise two tabs formed by H-shaped cutouts in the positive current collector <NUM>. The two tabs are each friction welded to the corresponding positive terminal <NUM>.

Each brick <NUM> further comprises fourth and fifth electrical insulators <NUM> and <NUM> which form its rearward-most and forward-most layers respectively. The fourth and fifth electrical insulators <NUM> and <NUM> each cover a substantial portion of the rearward-and forward-facing faces of the negative and positive current collectors <NUM> and <NUM>, respectively. The first, second, third, fourth and fifth electrical insulators <NUM>, <NUM>, <NUM>, <NUM> and <NUM> of the present implementation are formed from sheets of electrical insulation paper, such as ThermaVolt™ manufactured by <NUM>™, which is held in place by an adhesive backing.

The cells <NUM> are arranged within the PCM block <NUM> in an alternating pattern that forms a plurality of channels <NUM> across the top of the PCM block <NUM>. The first, second, third, fourth and fifth electrical insulators <NUM>, <NUM>, <NUM>, <NUM> and <NUM> comprise corresponding shapes along their upper sides/edges. The present implementation of the PCM block <NUM> and the <NUM> slots <NUM> that receive the <NUM> cells <NUM> are shown in more detail in <FIG>. The slots <NUM> are aligned in nine columns 98a to 98i of five slots <NUM> each, i.e. the longitudinal axis 100a of a given slot <NUM> will be aligned with the longitudinal axes 100b and 100c of the slots <NUM> above and below it. Each column 98a to 98i is offset vertically from the adjacent column(s) to the left and/or to the right of it, i.e. the longitudinal axis 100a of the slot <NUM> will not be aligned with longitudinal axes 100e to <NUM> of the slots <NUM> to the left and to the right of it. As such, a given cell <NUM> will have another cell <NUM> immediately above and/or below it at the same horizontal position across the width of the PCM block <NUM> (thereby forming the columns 98a to 98i), but the cells <NUM> to the left and/or right of it will not be at the same vertical position across the height of the PCM block <NUM>. In the present implementation, the longitudinal axes 100e to <NUM> are vertically offset from the longitudinal axis 100a (either upwards or downwards) by half the distance between the longitudinal axes 100a and the longitudinal axes 100b and 100c above and below it. This alternating pattern permits a tighter packing of the cells <NUM> within the PCM block <NUM> and a reduction in the width of the PCM block <NUM>. Staggering the cells <NUM> in this way also allows the formation of channels 96a to 96e along the top side of the PCM block <NUM> beside and between the second, fourth, sixth and eighth columns 98b, 98d, 98f and <NUM>.

It is contemplated that channels similar to those shown in <FIG> could be provided along the bottom side of the PCM block <NUM> either in addition to or in place of the channels 96a to 96e. While the present implementation comprises an alternating pattern of columns, it is contemplated that the cells <NUM> and slots <NUM> could similarly be arranged in an alternating pattern of rows that form channels along the left and/or right sides of the PCM block <NUM>.

The modules <NUM> shown in the present implementation each comprise seven bricks <NUM>, although it is contemplated that more or less bricks <NUM> could be provided per module <NUM>. It is contemplated that between six and <NUM> bricks <NUM> could be provided. The cells <NUM> of the brick <NUM> are connected in parallel via the negative and positive current collectors <NUM> and <NUM> which connect the negative and positive terminals <NUM> and <NUM>, respectively, of each cell. The seven bricks <NUM> of each module <NUM> are connected in series, that is to say the negative current collector <NUM> of one brick <NUM> is connected to the positive current collector <NUM> of an adjacent brick <NUM> such that the voltage of the module <NUM> is the sum of the voltages of the bricks <NUM> therein. As discussed above, the four modules <NUM> are also connected in series.

With reference to <FIG>, two exemplary bricks 40a and 40b are shown in a partially exploded state to illustrate the connection therebetween. For clarity, the elements of the left brick 40a (with respect to the frame of reference of <FIG>) are labeled with the suffix "a" while, similarly, the elements of the adjacent right brick 40b are labeled with the suffix "b". When assembled, the fifth electrical insulator 94a of the left brick 40a is adjacent the fourth electrical insulator 92b of the right brick 40b. The presence of the electrical insulators 94a and 92b separate the negative and positive current collectors 88a and 84b, except along their upper edges where they will be connected as described below. The electrical insulators 94a and 92b prevent the contact portions 90a of the positive current collector 88a from coming into contact with the contact portions 86b of the negative current collector 84b.

The positive and negative current collectors 88a and 84b of the adjacent bricks 40a and 40b are electrically connected by a plurality of connectors <NUM> which are embodied herein by bolts <NUM>, nuts <NUM> and washers <NUM>. Each bolt <NUM> passes through a hole 112a in the positive current collector 88a and a corresponding hole 114b in the negative current collector 84b. The washers <NUM> sandwich the portion of the negative and positive current collectors 88a and 84b around the holes 112a and 114b, ensuring a contact therebetween. In addition, the bolts <NUM>, nuts <NUM> and washers <NUM> are metallic and can conduct current between the bricks 40a and 40b. The holes 112a and 114b are located along the top edge of the positive and negative current collectors 88a and 84b, respectively, such that the bolts <NUM>, the nuts <NUM> and the washers <NUM> are located in the channels <NUM>. In the present implementation, there are four pairs of holes 112a and 114b, each within a channel <NUM>. It will be appreciated that various alternative ways of connecting negative and positive current collectors 88a and 84b, such as welding, rivets, clamps, clips and the like. It is also contemplated that adjacent current collectors 88a and 84b could be formed from a single conductive sheet folded in half with one or both of the electrical insulators 94a and 92b therebetween.

<FIG> and <FIG> show seven bricks 40a to <NUM> connected in series between the positive and negative terminals <NUM> and <NUM>. The charge path (indicated in with arrows and representing a positive current direction as seen by the BMS <NUM>) begins at the positive terminal <NUM> which his connected to the first brick 40a via a first bus bar <NUM>. The first bus bar <NUM> is connected to the positive current collector <NUM> of the first brick 40a via connectors <NUM> which engage the holes <NUM> of the first brick 40a and a corresponding set of holes (not shown) in the bus bar <NUM> in a manner similar to that described above. The negative current collector <NUM> of the first brick 40a is connected to the positive current collector <NUM> of the second brick 40b, the negative current collector <NUM> of the second brick 40b is connected to the positive current collector <NUM> of the third brick 40c, and the negative current collector <NUM> of the third brick 40c is connected to a second bus bar <NUM>. These connections are all made via connectors <NUM> which engage holes <NUM> and/or <NUM>.

The charge path continues through the second bus bar <NUM> to the positive current collector <NUM> of the fourth brick 40d. The negative current collector <NUM> of the fourth brick 40d is connected to the positive current collector <NUM> of the fifth brick 40e, the negative current collector <NUM> of the fifth brick 40e is connected to the positive current collector <NUM> of the sixth brick 40f, the negative current collector <NUM> of the sixth brick 40f is connected to the positive current collector <NUM> of the seventh brick <NUM>, and the negative current collector <NUM> of the seventh brick <NUM> is connected to a third bus bar <NUM>. Again, these connections are all made via connectors <NUM> which engage holes <NUM> and/or <NUM>.

The charge path continues from the third bus bar <NUM> to the fuse <NUM>, the current sensor <NUM> and ends at the negative terminal <NUM>. The internal components of the negative and positive terminals <NUM> and <NUM>, the bus bar <NUM>, the current sensor <NUM>, the fuse <NUM> and the BMS <NUM> (not shown in <FIG> and <FIG>) occupy a space roughly the size of a brick <NUM>. The present architecture of seven bricks <NUM> and the accompanying electrical and electronic components form a substantially U-shaped package within the module <NUM>. It is contemplated that the bricks <NUM> could be arranged and connected in other formations, such as in a single line, in an S shape or and M shape.

The BMS <NUM> of each module <NUM> monitors and logs the temperature and voltage of each brick <NUM>, and the current through the module <NUM> (via the sensor <NUM>) to ensure these parameters stay within their operational limits. The BMS <NUM> can register fault and/or error codes when those limits are exceeded. The BMS <NUM> also calculates the state of charge and state of health of the module <NUM> and bricks <NUM>. Each BMS <NUM> outputs this information via the communication terminal <NUM> to the vehicle's CAN-bus network to a vehicle control module (not shown) that also communicates with the vehicle's motor controller(s).

The cells <NUM> are lithium-ion rechargeable cells. More particularly, they are lithium-nickel-manganese-cobalt cells (NMC), although other types of cells are contemplated. For example, it is contemplated that the cells <NUM> could be lithium-nickel-cobalt-aluminum (NCA), lithium-manganese-spinel (LMO), lithium-titanate (LTO), lithium-iron-phosphate (LFP) cells or lithium sulfur (Li-S). The nominal voltage of each NMC cell <NUM> is <NUM>. Accordingly, the voltage of each brick <NUM> is <NUM>. 65V, the voltage of each module <NUM> comprising seven bricks <NUM> is <NUM>. 55V and the voltage of each pack <NUM> comprising four modules <NUM> is <NUM>. Such a module is said to have a nominal voltage of 24V and such a pack <NUM> is considered to have a nominal voltage of 96V. In the present implementation, each module <NUM> has <NUM>. 5kwh at 24V resulting in 10kwh at 96V with 30kW continuous power and 55kW peak power for the pack <NUM>. It will be appreciated that NCA cells have an equivalent voltage to NMC cells and as such the resultant voltages of the bricks <NUM>, modules <NUM> and packs <NUM> comprising NCA cells would be equivalent to those of the NMC cells <NUM>. It is contemplated that a 120V pack <NUM> comprising Li-S cells having a nominal voltage of <NUM>. 2V could also be provided.

The PCM block <NUM> acts as a heat sink during discharge of the cells <NUM>. Preventing the cells <NUM> from getting too hot during discharge is important to both prevent thermal runaway and protect the cells from damage which could reduce their performance and lifespan, as is maintaining an even temperature across all the cells <NUM> of a given brick <NUM>. It is contemplated that the PCM block <NUM> could be formed from a wax and graphite matrix PCM material, such as the Phase Change Composite (PCC™) material manufactured by Allcell. During discharge, as the cells <NUM> heat up, the PCM block <NUM> thermally conducts that heat to spread it out evenly across the brick <NUM>. As the temperature of the brick <NUM>, or any parts thereof, approaches the melting point of the PCM block <NUM> (Tmelt), heat energy begins to be absorbed by the melting (i.e. phase change) process. The proportion of the PCM block <NUM> that has melted at a given moment is referred to as the liquid fraction. When the liquid fraction has reached <NUM>%, every part of the brick <NUM> will have reached Tmelt and the PCM material can absorb no further heat. Once discharge has stopped, the PCM block <NUM> will release the heat absorbed during discharge to the surrounding environment and the liquid fraction will eventually return to <NUM>%.

Different PCM materials will have different Tmelt, for example PCM materials are available that have <NUM>, <NUM> or <NUM>. The PCM block <NUM> is selected so that the Tmelt is below a maximum desired operating temperature during discharge (Tmax-discharge) in order to help prevent thermal runaway and damage to the cells <NUM> and above the maximum ambient temperature of operation of the battery pack <NUM>. For example, in the present implementation the Tmax-discharge of the cells <NUM> is <NUM>. The PCM block <NUM> is therefore selected to have a Tmelt lower than <NUM>. It is common to select PCM material that has the highest Tmelt lower than the Tmax-discharge.

However, the cells <NUM> also have a maximum temperature at which they can be charged (Tmax-charge). Tmax-charge is typically less than Tmax-discharge. For example, the cells <NUM> of the present implementation have a Tmax-charge of <NUM>. Cells <NUM> that have reached a temperature above Tmax-charge during operation (i.e. discharge) cannot be charged until the pack <NUM> has cooled to below Tmax-charge. A conventional battery pack with cells having a Tmax-discharge of <NUM> and a PCM material having a Tmelt of <NUM> that undergoes heavy usage and discharge of the cells that necessitates absorption by the PCM material will not be able to be recharged immediately after usage since the battery pack must cool to <NUM> (Tmax-charge). The PCM block <NUM> of the present implementation therefore comprises a PCM material with a Tmelt lower than the Tmax-charge in order to ensure that the cells <NUM> will be ready to be recharged immediately after they are discharged. This can be especially advantageous in implementations where quick recharging is desirable.

As mentioned above, the BMS <NUM> monitors the voltage of each brick <NUM>. With reference to <FIG> and <FIG>, a module <NUM> is shown with a voltage monitoring assembly <NUM> which links the BMS <NUM> to each of the bricks 40a to <NUM>. The voltage monitoring assembly <NUM> comprises a wire harness <NUM> comprising eight wires 126a to <NUM> which connect the BMS <NUM> to points before and after each brick 40a to <NUM>. A first extremity of the first wire 126a is connected to the positive current collector <NUM> of the first brick 40a. A first extremity of the second wire 126b is connected to the negative current collector <NUM> of the first brick 40a and the positive current collector <NUM> of the second brick 40b. A first extremity of the third wire 126c is connected to the negative current collector <NUM> of the second brick 40b and the positive current collector <NUM> of the third brick 40c. A first extremity of the fourth wire 126d is connected to the positive current collector <NUM> of the fourth brick 40d and the second bus bar <NUM>. A first extremity of the fifth wire 126e is connected to the negative current collector <NUM> of the fourth brick 40d and the positive current collector <NUM> of the fifth brick 40e. A first extremity of the sixth wire 126f is connected to the negative current collector <NUM> of the fifth brick 40e and the positive current collector <NUM> of the sixth brick 40f. A first extremity of the seventh wire <NUM> is connected to the negative current collector <NUM> of the sixth brick 40f and the positive current collector <NUM> of the seventh brick <NUM>. A first extremity of the eighth wire <NUM> is connected to the negative current collector <NUM> of the seventh brick <NUM> and the third bus bar <NUM>.

The first extremities of each wire 126a to <NUM> are electrically connected to respective positive and negative current collectors <NUM> and <NUM> via connectors <NUM> in the manner described above. The harness <NUM> extends along a central channel <NUM> formed along the center of the module by the innermost channels <NUM> of the bricks 40a to <NUM>. The connections between the first extremities of the wires 126a to <NUM> and the bricks 40a to <NUM> are made within the central channel <NUM>.

Each wire 126a to <NUM> comprises a second extremity opposite its respective first extremity that is connected to a voltage monitoring assembly connector <NUM> that plugs into the BMS <NUM>. The BMS <NUM> is therefore provided with the voltage before and after each brick 46a to <NUM>, thereby enabling monitoring of the voltage of each brick 46a to <NUM>.

The harness <NUM> further comprises a first power wire 132a having a first extremity connected to a BMS power connector <NUM> and a second extremity connected to the positive current collector <NUM> of the first brick 40a. The voltage monitoring assembly <NUM> further comprises a second power wire 132b having a first extremity connected to the BMS power connector <NUM> and a second extremity connected to the negative current collector <NUM> of the seventh brick <NUM> and the third bus bar <NUM>. The first and second power wires 132a and 132b provide the 24V of the module <NUM> to power the BMS <NUM>.

As mentioned above, the BMS <NUM> also monitors the temperature of each brick 40a to <NUM>. With reference to <FIG> and <FIG>, a module <NUM> is shown with a temperature monitoring assembly <NUM>. The assembly <NUM> comprises a wire harness <NUM> comprising eight wires 140a to <NUM> which connect the BMS <NUM> to points across the module <NUM>. The first extremity of each wire 140a to <NUM> is connected to a thermistor <NUM>. The second extremity of each wire 140a to <NUM> is connected to a temperature monitoring assembly connector <NUM> that plugs into the BMS <NUM>.

The thermistor <NUM> of the first wire 140a is connected, via a connector <NUM>, to the first bus bar <NUM>. The thermistors of the wires 140b to <NUM> are each in contact with a respective one of the PCM blocks <NUM> of the bricks 40a to <NUM>. Specifically, these thermistors <NUM> are passed through an opening in respective electrical insulators <NUM>, <NUM> and/or <NUM> so as to contact respective PCM blocks <NUM> directly. The thermistors <NUM> can be glued or otherwise fixed in position. Like the wire harness <NUM> of the voltage monitoring assembly <NUM>, the wires 140a to <NUM> of the wire harness <NUM> extend from the connector <NUM> through the channel <NUM> formed by the innermost channels <NUM> of the bricks 40a to <NUM>.

Claim 1:
A process for constructing a battery brick (<NUM>) for a vehicle, the process comprising:
selecting a plurality of battery cells (<NUM>) having a maximum charge temperature and having a maximum discharge temperature greater than the maximum charge temperature;
selecting a phase change material having a melting temperature lower than the maximum charge temperature of the plurality of cells; and
disposing each battery cell of the plurality of battery cells at least in part in the phase change material, the phase change material being selected for dissipating at least a portion of heat generated upon activation of at least a portion of the plurality of battery cells.