with reference to fig1 and 2 , an embodiment of an ultracapacitor energy storage cell pack 10 will now be described . fig1 illustrates an exploded view of an embodiment of a half module 15 of the ultracapacitor energy storage cell pack 10 . fig2 illustrates an embodiment of an assembled ultracapacitor energy storage cell pack module 10 , which includes two half modules 15 fastened together . although each half module 15 is shown as having seventy - two ultracapacitors 20 , each half module may have other numbers of ultracapacitors 20 . further , the ultracapacitor pack 10 may have other numbers of modules 15 besides a pair ( e . g ., 1 , 3 , 4 , etc .). the ultracapacitor pack 10 is shown in exploded view in fig1 to illustrate the different levels in the half module 15 that are added during assembly of the half module 15 . each of these levels will now be described in turn below followed by a description of the assembly process . an aluminum base plate 25 forms a bottom or inner - most level of the half module 15 . the base plate 25 includes a welded frame 30 around edges of the base plate 25 . a polycarbonate crate plate 35 is seated inside the frame 30 and includes cutouts or holes 40 with a shape that matches the cross - section of the ultracapacitors 20 . the base plate 25 and crate cutouts 40 form an x , y , and z location and mounting support for the ultracapacitors 20 . the cutouts 40 also prevent the ultracapacitors 20 from rotating during use , e . g ., mobile vehicle use . in the embodiment shown , the individual ultracapacitors 20 have a general square - can shape ( i . e ., rectangular parallelpiped ). the cross - section of the ultracapacitors 20 is 2 . 38 in . by 2 . 38 in . and the length is about 6 in . on an upper - most or outer - most end of the ultracapacitor 20 , two threaded lug terminals 45 and a dielectric paste fill port 50 protrude from an insulated cover 55 of the ultracapacitor 20 . the cover 55 of the ultracapacitor may include a well encircled by a protruding rim . shrink plastic that normally surrounds sides or exterior capacitor casing 60 of the ultracapacitor 20 is removed to better expose the exterior casing 60 to circulated cooling air . the shrink plastic may be left on the bottom of the ultracapacitor 20 . a box frame 65 ties together the base plate 25 and frame 30 with circuit boards 70 , and a top polycarbonate cover 75 . the box frame 65 has elongated lateral cutouts 80 on two opposing sides to provide for cross - flow air cooling . bottom flanges 85 provide a mounting surface to tie two of these box frames 65 , and , hence , two half modules 15 , together to form the single ultracapacitor pack module 10 shown in fig2 . the box frame 65 includes a large upper rectangular opening and a large lower rectangular opening . the next layer is a first ¼ - in . foam rubber insulating and sealing sheet 90 that covers the ultracapacitors 20 . the first sheet 90 has cutouts for the ultracapacitor terminals 45 and fill port 50 so that the sheet 90 can seal tightly against the cover 55 of the ultracapacitor 20 . a second ⅛ - in . foam rubber insulating and sealing sheet 95 may be placed on top of the previous first sheet 90 . the second sheet 95 includes rectangular cutouts or holes 100 . the cutouts 100 receive copper bar electrical interconnections 105 . the cutouts 100 in the sheet 95 simplify the assembly and proper placement of the copper bar electrical interconnections 105 . the sheet 95 also seals the copper bar electrical interconnections 105 . the copper bar electrical interconnections 105 include holes that the ultracapacitor terminals 45 protrude through . two identical main circuit boards 70 ( e . g ., 40 - ultracapacitor main circuit boards ) may lay on top of the foam rubber sheets 90 , 95 . each main circuit board 70 may include holes that the ultracapacitor terminals 45 protrude through . each circuit board 70 may have mounting holes for 40 ( 8 by 5 ) ultracapacitors less two corner positions required for frame structure mounting . instead of two circuit boards 70 , a single circuit board 70 may be used . thus , as used herein , the word “ circuit board ” means one or more circuit boards . fasteners such as lug nuts fasten the individual ultracapacitor terminals 45 and copper bars 105 to the circuit boards 70 and compress the foam rubber sheets 90 , 95 in between the cover 55 of the ultracapacitor 20 and the circuit boards 70 . thus , the circuit board 70 forms the location and mechanical support as well as the electrical connections for the ultracapacitors 20 . the foam sheets 90 , 95 seal around the rim of the ultracapacitor terminals 45 . a processor and display circuit board mounts on top of the main circuit board 70 . although the ultracapacitor pack 10 and the half modules 15 are shown as being generally rectangular in shape , either or both may have shapes other than generally rectangular such as , but not by way of limitation , circular , oval , other curvilinear shapes , other rectilinear shapes , and other polygonal shapes . a top aluminum frame 110 and the transparent polycarbonate cover 75 may attach to the frame structure to complete the half module 15 . the transparent cover 75 allows observation of a light emitting diode ( led ) failure detection display that indicates the active / inactive status of the ultracapacitors 20 . together , the bottom base plate 25 , crate plate 35 , box frame 65 , sealing sheets 90 , 95 , and circuit board ( s ) 70 , and ultracapacitor terminal fasteners form an ultracapacitor mounting assembly 112 for the ultracapacitors 20 . the ultracapacitor mounting assembly 112 provides a mounting surface for the copper bar interconnects 105 , maintains the position and spacing of the ultracapacitors 20 in the x , y , and z directions , does not allow the ultracapacitors to rotate when connected , and the main circuit board ( s ) 70 provides a mounting platform for the cell equalization , failure detection , processor , and led display systems . attaching the ultracapacitors 20 to the mounting assembly 112 by the terminals 45 instead of the exterior ultracapacitor casing 60 allows the ultracapacitors 20 to be more effectively cooled because the majority of the surface area of the ultracapacitors 20 is in the cooling air stream supplied by the cross - flow air cooling assembly 115 . sealing along the cover 55 and around the terminals 45 protects the terminals 45 from water , dust , and other contaminants . an exemplary method of assembling the ultracapacitor half module 15 will now be described . the ultracapacitors 20 are first placed onto the bottom base plate 25 , with the bottoms of the ultracapacitors 20 extending through the square cutouts 40 of the crate plate 35 . the box frame 65 is applied over the ultracapacitors 20 , so that the ultracapacitors extend through the large lower and upper rectangular openings of the box frame 65 . the ¼ - in . foam rubber insulating and sealing sheet 90 is placed on top of the ultracapacitors 20 , with the ultracapacitor terminals 45 and fill port 50 protruding through cutouts in the sheet 90 . the ⅛ - in . foam rubber insulating and sealing sheet 95 is placed on top of the previous sheet 90 and the copper bar electrical interconnections 105 are placed into the rectangular cutouts 100 of the sheet 95 . the ultracapacitor terminals 45 also protrude through holes in the copper bar electrical interconnections 105 . the main circuit boards 70 are layered on top of the foam rubber sheets 90 , 95 so that the threaded ultracapacitor terminals 45 protrude through the corresponding holes in the circuit boards 70 . lug nuts are screwed onto the threaded terminals 45 , compressing the foam rubber sheets 90 , 95 in between the cover 55 of the ultracapacitor 20 and the circuit boards 70 , and securing the ultracapacitors 20 and copper bars 105 in position . the processor and display circuit board is mounted on top of the main circuit board 70 . the top aluminum frame 110 and the transparent polycarbonate cover 75 are placed over the circuit boards and attached to the frame structure to complete the half module 15 . a pair of half modules 15 may be positioned back to back ( i . e ., facing opposite directions with the bottoms of the aluminum base plates 25 touching ) and a cross - flow air cooling assembly 115 may be attached to the frame structure , adjacent the elongated lateral cutouts 80 on one side of the box frames 65 . the half modules 15 may be bolted or otherwise fastened together at the respective bottom flanges 85 to complete the ultracapacitor pack module 10 . to determine if one or more ultracapacitors 20 in the pack 10 need to be replaced , a user observes the light emitting diode ( led ) failure detection display through the transparent cover 75 . the led failure detection display includes an array of leds that correspond to the array of ultracapacitors 20 , each led indicating the status of a corresponding ultracapacitor 20 . each unlit led indicates a corresponding failed led . an ultracapacitor 20 in the pack 10 can quickly and easily be replaced by simply unfastening the frame and unbolting only the failed ultracapacitor 20 that had been previously identified by the led display . the replacement ultracapacitor is put into position and the procedure reversed . with reference to fig3 – 8 , and initially , fig3 and 4 , an ultracapacitor energy storage cell pack ( hereinafter “ ultracapacitor pack ii ”) 200 constructed in accordance with another embodiment of the invention will now be described . the ultracapacitor pack 200 includes a ultracapacitor cell and winerack support assembly ( hereinafter “ ultracapacitor assembly ”) 210 , an ultracapacitor pack box enclosure ( hereinafter “ box enclosure ”) 220 , a metal lid 230 , an air filter bracket 240 ( w / air filter ), cooling fans 250 , fan finger guards 260 , an optional higher - power precharge resistor 270 , programmable logic controller ( plc ) module 280 , high power relays ( kilovac contactors ) 290 , electrical connectors 300 , 310 , 320 and other discrete components mounted within the box enclosure 220 . the ultracapacitor assembly 210 includes one - hundred and forty - four ( 144 ) ultracapacitors 330 connected in series to provide a nominal 360 volts dc , 325 watt - hours energy storage . the value of each ultracapacitor 330 is 2600 farads . in alternative embodiments , the ultracapacitor assembly 210 may have other numbers of ultracapacitors , different types and sizes of ultracapacitors , and / or an overall different amount of voltage and / or power . each ultracapacitor 330 is connected with a parallel drain resistor 340 ( fig5 ). the ultracapacitor assembly 210 includes a first wine rack middle support plate 350 , a similar second wine rack middle support plate 360 , and a wine rack end support plate 370 for supporting the ultracapacitors 330 . the box enclosure 220 is preferably made of metal and includes square end cutouts 380 in rear wall 382 to accommodate air flow therethrough and circular cutouts 390 in front wall 392 to accommodate the cooling fans 250 . the front wall 392 and rear wall 382 are joined by opposite parallel side walls 394 . the filter ( s ) of the air filter bracket 240 is externally serviceable and fits over the square cutouts 380 of the rear wall 382 . the interior of the box enclosure 220 and underside of the lid 230 is coated with a thick material that provides electrical insulation and corrosion protection as an additional level of safety for the box enclosure 220 . the inner bottom of the box enclosure 220 includes support plate guides for mounting the wine rack middle support plates 350 , 360 and end support plate 370 . fig4 shows an exploded view of the ultracapacitor assembly 210 . the ultracapacitors 330 are cylindrical canisters with aluminum female threaded connections . the female threads are not shown , but each end of the capacitor canister has female threads that receive male threaded aluminum interconnection studs 400 and male threaded mounting bolts 402 . the shown adjacent shaft is the connecting stud 400 for connecting the ultracapacitors 330 in series . aluminum bus bars 410 are also used to interconnect the ultracapacitors 330 in series at the ends of the rows . interconnection washers are placed inside the bolts that fasten the buss bars 410 to the ends of the canister rows to provide a surface for the bolts to push against bigger than the hole and the head of the bolt . providing electrical connections made of aluminum metal prevents any corrosive galvanic effects from dissimilar metals . additionally , the threaded connections are covered with a silicon dielectric grease to prohibit environmentally caused corrosion . the wine rack middle support plates 350 , 360 and end support plate 370 are made of nonconductive plastic material to prevent any high - voltage arcing or other high - voltage leakage effects that could occur over time due to vibration , shock , and debris buildup . the wine rack middle support plates 350 , 360 and end support plate 370 are different in construction to allow ease of assembly and replacement of any canister row . with reference to fig6 , the wine rack middle support plates 350 , 360 include a pattern of generally circular cutouts 430 for receiving the ultracapacitors 330 . the cutouts 430 include an additional semi - circular recess 440 to accommodate and support the drain resistors 340 . the drain resistors 340 are preformed with ring terminals 442 ( fig5 ) attached to leads of the drain resistors 340 for simplicity of mounting and electrical connection . additional semi - circular recesses 450 along a top edge 460 and bottom edge 470 of the wine rack middle support plates 350 , 360 provide clearance for the attaching rivets of support guides on a bottom of box enclosure 220 and the lid 230 . the wine rack middle support plates 350 , 360 are made of 3 / 16 ″ thick polycarbonate plastic for strength and electrical insulation . with reference to fig7 , the wine rack end support plate 370 includes a pattern of circular holes 480 for receiving threaded bolt fasteners for mounting the ultracapacitors 330 . additional semi - circular recesses 490 along a top edge 500 and a bottom edge 510 of the wine rack end support plate 370 provide clearance for the attaching rivets of support guides on a bottom of the box enclosure 220 and the lid 230 . the wine rack end support plate 370 is made of 3 / 16 ′ thick grade g - 10 / fr4 garolite glass fabric laminate with an epoxy resin that absorbs virtually no water and holds its shape well . inside - mounted aluminum bus bars 410 are affixed in place to the wine rack end support plate 370 with silicon rtv , a common jelly like paste that cures to a rubbery substance used in various applications as a sealer and / or adhesive . the bus bars 410 are pre - positioned to avoid confusion that could cause assembly mistakes . fig8 is a general block diagram of the ultracapacitor pack 200 . as indicated above , each ultracapacitor 330 is connected in parallel with the drain resistor 340 . one - hundred and forty - four ( 144 ) of these parallel connections are connected in series to provide a nominal 360 volts dc , 325 watt - hours energy storage . the value of each ultracapacitor 330 is 2600 farads and the value and power of the drain resistor 340 is selected to completely discharge the ultracapacitor 330 over a number of hours during an inactive period of the ultracapacitor pack 200 . the energy drain action is slow enough so as not to interfere with the normal operation of the ultracapacitor pack 200 . the discharge is also slow enough so as not to cause any significant temperature increase from the drain resistors 340 within the ultracapacitor pack 200 . the chemical composition of the ultracapacitor 330 allows charge to build up across the ultracapacitor 330 over a period of time after the ultracapacitor 330 is shorted and left open . the drain resistors 340 allow a safe discharge of the high voltage of the ultracapacitor pack 200 to eliminate any shock danger from the ultracapacitor “ memory ” to personnel servicing the ultracapacitor pack 200 . because the ultracapacitors 330 can accept hundreds of amperes of electrical current during charging , a connection to an energy source would appear as a short circuit to the energy source . if an external current limiting circuit is not used , then to accommodate this problem , an optional high - power pre - charge resistor 270 with its own heat sink is mounted inside the box enclosure 220 and used to limit the initial charging current . based on input to a pack voltage sensor 520 , a programmable logic controller ( plc ) 530 controls a pre - charge contactor relay 540 to engage the pre - charge resistor 270 until the ultracapacitors 330 reach a minimum safe voltage level . the plc 530 is the control center for additional features . through a control area network ( can ) bus interface ( e . g ., sae standard j1939 ), the plc 530 offers remote on / off control and status reporting of : the control relay positions for on / off relay 550 and precharge relay 540 , pack voltage sensor 520 , ground fault interrupt ( gfi ) sensor 560 , cooling fans 250 , box temperature sensor 570 , over temperature sensor 580 , optional fire sensor 590 , and optional fire suppression system 600 . the plc 530 also uses input from the box temperature sensor 570 to turn on and off the cooling fans 250 . during normal operation of the ultracapacitor pack , the on / off relay 550 is activated . the on / off relay 550 is deactivated by the plc 530 when the gfi sensor 560 detects a ground fault interrupt condition , when the over temperature sensor 580 detects an over - temperature condition , or the pack voltage sensor 520 detects an over - voltage condition . the fire suppression system 600 is activated by the plc 530 in the event a fire condition is detected by the fire sensor 590 to extinguish any fire in the ultracapacitor pack 200 . the 360 vdc + stud feed thru 610 is the external power cable attachment for the positive side of the energy storage pack . the 360 vdc — stud feed thru 620 is the external power cable attachment for the negative side of the energy storage pack . the 24 vdc +, 24 vdc − power connector 630 is the positive and negative dc power connections for the plc 530 . the digital data interface connector 640 provides for connecting the wires to the pack that connect to the can buss network . this is also the port by which the plc 530 is programmed . the ultracapacitor pack 200 includes structural support , environmental protection , automatic cooling , electrical interconnection of the ultracapacitors , remote on / off switching , a safety pre - charge circuit , a safety and automatic equalizing discharge circuit , a programmable logic controller , a digital interface to a control area data network for control and status reporting , and an optional fire sensing and suppression system . the pack is ideal for high - voltage , high - power applications of electric and hybrid - electric vehicle propulsion systems , fixed site high - power load averaging , and high - power impulse requirements . while embodiments and applications of this invention have been shown and described , it would be apparent to those in the field that many more modifications are possible without departing from the inventive concepts herein . the invention , therefore , is not to be restricted except in the spirit of the appended claims .