Patent Publication Number: US-2012028085-A1

Title: Lithium ion battery for railroad locomotive

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/362,569, filed 8 Jul. 2010. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to starter batteries for railroad locomotives. 
     More particularly, the present invention relates to improved starter batteries for railroad locomotives. 
     BACKGROUND OF THE INVENTION 
     In the present day, lead acid batteries are used for starting locomotives as up until now no other battery technology was available. One major problem with lead acid batteries for use in starting locomotives is the fact that they weigh thousands of pounds and require two 32 volt units tied in series for a common 64 volt battery unit. Another problem is that lead acid batteries do not fare well with deep discharges, which can occur rather frequently. In addition sulfation occurs when the batteries are not kept fully charged. Further, lead acid batteries require substantial amounts of time to recharge. All of this, results in significantly shortened life cycles for lead acid locomotive starter batteries. Also, these batteries require periodic maintenance to maintain water levels. 
     Some attempts have been made to substitute Lithium ion batteries based on cobalt chemistry (LiCoO 2  or LCO) for the lead acid batteries. However, the cobalt type batteries are thermally unstable and are prone to thermal runaway. The thermal runaway is highly unsatisfactory since it can cause fires, explosions, and harm to personnel adjacent thereto. 
     It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art. 
     An object of the present invention is to provide new and improved safe Lithium ion battery starting apparatus for railroad locomotives. 
     Another object of the present invention is to provide Lithium ion battery starting apparatus for railroad locomotives that is smaller and relatively easy to handle. Another object of the present invention is to provide Lithium ion battery starting apparatus for railroad locomotives with three to five times the life cycle of lead acid batteries. 
     Another object of the present invention is to provide Lithium ion battery starting apparatus for railroad locomotives in which the batteries can be quickly recharged and/or changed and easily replaced in a matter of minutes. 
     Another object of the present invention is to provide Lithium ion battery starting apparatus for railroad locomotives that requires no or substantially reduced maintenance. 
     SUMMARY OF THE INVENTION 
     Briefly, to achieve the desired objects of the instant invention in accordance with a preferred embodiment thereof, provided is battery starting apparatus for railroad locomotives that is portable and requires substantially no maintenance. A Lithium Iron Phosphate chemistry Lithium ion battery is carried within a housing. The battery has a positive output lead and a negative output lead accessible from the exterior of the housing. A low voltage and high voltage protection module is positioned within the housing and connected to the positive output lead and the negative output lead. The module is constructed to switch the battery into a “sleeping mode” when the battery voltage reaches a low voltage or a high voltage condition. A pair of output terminals is connected to the positive output lead and the negative output lead. The output terminals are mounted on an exterior surface of the housing in a location available to be connected to a locomotive by interconnecting cables. 
     In another aspect of the present invention, a method of connecting a battery to a railroad locomotive for starting the locomotive includes the step of providing Lithium Iron Phosphate chemistry Lithium ion battery starting apparatus carried within a housing, the battery starting apparatus including a positive output lead and a negative output lead accessible from the exterior of the housing, a low voltage and high voltage protection module positioned within the housing and connected to the positive output lead and the negative output lead, the module being constructed to switch the battery into a “sleeping mode” when the battery voltage reaches either a low or a high voltage condition, and a pair of output terminals connected to the positive output lead and the negative output lead. The method further includes connecting the battery apparatus to a locomotive by interconnecting cables coupled between the locomotive and the pair of output terminals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Specific objects and advantages of the instant invention will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment thereof taken in conjunction with the drawings, in which: 
         FIG. 1  is a perspective view of Lithium ion battery apparatus for railroad locomotives in accordance with the present invention; 
         FIG. 2A  is a wiring diagram of the Lithium ion battery apparatus of  FIG. 1 ; 
         FIG. 2   b  is a more detailed portion of the wiring diagram of  FIG. 2A ; and 
         FIG. 3  is a graphical presentation of the voltage drop versus load of the Lithium ion battery of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is first directed to  FIG. 1  which illustrates Lithium ion battery apparatus  10  for starting railroad locomotives in accordance with the present invention. As can be seen from  FIG. 1 , battery apparatus  10  has much smaller dimensions than prior art lead acid batteries and weighs substantially less. Thus, it can be conveniently moved from a storage or non-working position to a position within a locomotive on a simple cart  12  or the like by a single employee. Also, cables and other equipment can be easily carried and stored on cart  12  for convenience of operation. 
     Battery apparatus  10  is carried in a case or housing  14 , which may include convenient handles  16  for moving battery apparatus  10  from cart  12  or even in moving battery apparatus  10  with cart  12 . Also, housing  14  includes a cover  18  so that the batteries and other circuitry are enclosed and protected. To provide the protection, housing  13  and cover  18  are preferably made of steel. A negative output terminal  20  and a positive output terminal  22  are mounted on cover  18  in a convenient location so they can be easily connected to a locomotive by interconnecting cables (not shown). 
     Turning additionally to  FIG. 2A , a wiring diagram of Lithium ion battery apparatus  10  is illustrated. Battery apparatus  10  includes a single 64 volt Lithium ion battery unit  25  carried within housing  14 . Lithium ion battery unit  25  is based on newly developed Lithium Iron Phosphate chemistry (LiFePO 4  or LEP). The newly developed Lithium iron phosphate technology has the features of safety, excellent cycle life, uncompromising performance, quick charge times, no or virtually no maintenance, and is environmentally friendly (i.e. contains no harmful heavy metals). Lithium ion battery unit  25  weighs approximately 170 pounds and has much smaller dimensions than prior art lead acid battery units. Because of the relatively light weight no heavy equipment is required for battery handling. Also, because of the relatively light weight and ease of handling, Lithium ion battery unit  25  can be sent back to a purveyor for replacement for less than the cost and effort of providing a new unit, which eliminates recycling issues. 
     Lithium ion battery unit  25  is designed for regular deep cycle uses, which are undesirable in lead acid batteries. However, ‘deep discharges’ does not mean that Lithium ion battery unit  25  is drained to zero volts. Illustrated in  FIG. 3  is a graphical presentation of the voltage drop versus load of Lithium ion battery unit  25 . Lithium ion battery unit  25  has a minimum threshold voltage that should not be crossed. If unprotected and Lithium ion battery unit  25  is over discharged (i.e. the minimum threshold voltage is crossed), permanent damage to the cells will occur. This over discharge situation will not however, pose a safety hazard to operating personnel. 
     In the present application, Lithium ion battery unit  25  is protected from over discharge with a special voltage sensing internal circuit board  40 . Circuit board  40  is contained within a voltage protection module (VPM)  30  connected to a positive output lead  32  and a negative output lead  34  to continually sense the output voltage when Lithium ion battery apparatus  10  is connected to a locomotive. Also, a positive output lead  36  is connected from module  30  to positive output terminal  22  of the pair of terminals  20  and negative output lead  34  continues on and is connected to negative output terminal  20 . Circuit board  40  within module  30  essentially removes Lithium ion battery unit  25  from the locomotive circuit, i.e. switches the battery into a “sleeping mode” when the battery reaches a low voltage or a high voltage condition. In this preferred embodiment the pre-programmed low voltage condition is approximately 62 volts and the high voltage is approximately 79 volts. 
     Referring additionally to  FIG. 2B  the internal wiring of module  30  is illustrated in more detail. Circuit board  40  has an input terminal  42  coupled to the negative terminal  20 / 34  of battery  25  and an input terminal  44  coupled to positive output terminal  22  so that the output voltage of module  30  is continuously applied to the input of circuit board  40 . Also, circuit board  40  has an output lead  46  connected to one power terminal of a solenoid type switch  50  and an output lead  48  connected to a second power terminal of solenoid type switch  50 . Switch  50  has a contact  52  that completes a circuit from positive battery terminal  32  to positive output terminal  22  when power is applied to the terminals from leads  46  and  48 . While a solenoid type switch is illustrated for simplicity it will be understood that any type of switch that operates as described can be utilized. 
     Circuit board  40  includes high and low voltage sensors which remove power (switches the battery into a “sleeping mode”) from leads  46  and  48  when a voltage below approximately 62 volts or a voltage above approximately 79 volts is sensed at input terminals  42  and  44 . A reset button  56  is connected between negative output terminal  34  of battery  25  and output line  46  of circuit board  40 . To reactivate Lithium ion battery  25 , the operator simply pushes reset button  56 , generally situated conveniently on the side of housing  14 , for approximately 2 seconds. Reset button  56  temporarily connects lead  46  and the negative terminal of switch  50  to the negative terminal of battery  25 , i.e. applies power to close switch  50 . Once switch  50  closes power from battery  25  is again applied to output terminals  20  and  22 , as well as input terminals  42  and  44  of circuit board  40 . If the power is within the specified limits circuit board  40  maintains switch  50  closed. When voltage protection module  30  switches battery apparatus  10  into the “sleeping mode” the battery voltage will read approximately zero volts at input terminals  42  and  44  until push button  56  is used to reactivate the apparatus. 
     As indicated above, Lithium ion battery unit  25  is based on newly developed Lithium Iron Phosphate chemistry (LiFePO 4  or LEP). Some specifications for the newly developed Lithium iron phosphate technology include:
         Lithium ion battery unit  25  are:   Dimensions—L 22″×W 19″×H 14″   Nominal voltage—64 volts   Capacity—72.8 Amp hours   Battery—4659.2 Watt hours   Cold Cranking Amps—1200 Amps   Peak Amps—2800 Amps for 5 seconds   Recommended Charge Cutoff—72-74 volts   Max steady charge rate—75 Amps   Embedded computer board—Programmed to shut off Battery if voltage drops below 62 volts for 90 consecutive seconds or rises above 79 volts.   Operating temperatures—120 F to −20 F       

     If Lithium ion battery apparatus  10  is colder than −20 F it may not “turn-over or start” the engine on the first attempt. The operator should try starting as normal and, if the engine doesn&#39;t start, wait 20-30 seconds and try again. Often times the load on the battery will generate enough internal battery heat to warm the battery to &gt;−20 F and allow the battery to function normally. It should be noted that it does not harm the battery to store it at a temperature &lt;−20 F. At temperatures colder than −20 F the battery charge and discharge performance will be inefficient but will not harm the battery. 
     Thus new and improved Lithium ion battery apparatus for starting railroad locomotives is disclosed. The Lithium ion battery apparatus for starting railroad locomotives is smaller than prior art batteries and is relatively easy to handle. Also, the Lithium ion battery apparatus for starting railroad locomotives has three to five times the life cycle of lead acid batteries and can be quickly recharged and/or changed and easily replaced in a matter of minutes. Further, the Lithium ion battery apparatus has the features of safety, excellent cycle life, uncompromising performance, quick charge times, no or virtually no maintenance, and is environmentally friendly (i.e. contains no harmful heavy metals). 
     Various changes and modifications to the embodiments herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof which is assessed only by a fair interpretation of the following claims. 
     Having fully described the invention in such clear and concise terms as to enable those skilled in the art to understand and practice the same, the invention claimed is: